Source file src/cmd/compile/internal/ssagen/ssa.go

     1  // Copyright 2015 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package ssagen
     6  
     7  import (
     8  	"bufio"
     9  	"bytes"
    10  	"cmp"
    11  	"fmt"
    12  	"go/constant"
    13  	"html"
    14  	"internal/buildcfg"
    15  	"internal/goexperiment"
    16  	"internal/runtime/gc"
    17  	"os"
    18  	"path/filepath"
    19  	"slices"
    20  	"strings"
    21  
    22  	"cmd/compile/internal/abi"
    23  	"cmd/compile/internal/base"
    24  	"cmd/compile/internal/ir"
    25  	"cmd/compile/internal/liveness"
    26  	"cmd/compile/internal/objw"
    27  	"cmd/compile/internal/reflectdata"
    28  	"cmd/compile/internal/rttype"
    29  	"cmd/compile/internal/ssa"
    30  	"cmd/compile/internal/staticdata"
    31  	"cmd/compile/internal/typecheck"
    32  	"cmd/compile/internal/types"
    33  	"cmd/internal/obj"
    34  	"cmd/internal/objabi"
    35  	"cmd/internal/src"
    36  	"cmd/internal/sys"
    37  
    38  	rtabi "internal/abi"
    39  )
    40  
    41  var ssaConfig *ssa.Config
    42  var ssaCaches []ssa.Cache
    43  
    44  var ssaDump string     // early copy of $GOSSAFUNC; the func name to dump output for
    45  var ssaDir string      // optional destination for ssa dump file
    46  var ssaDumpStdout bool // whether to dump to stdout
    47  var ssaDumpCFG string  // generate CFGs for these phases
    48  const ssaDumpFile = "ssa.html"
    49  
    50  // ssaDumpInlined holds all inlined functions when ssaDump contains a function name.
    51  var ssaDumpInlined []*ir.Func
    52  
    53  // Maximum size we will aggregate heap allocations of scalar locals.
    54  // Almost certainly can't hurt to be as big as the tiny allocator.
    55  // Might help to be a bit bigger.
    56  const maxAggregatedHeapAllocation = 16
    57  
    58  func DumpInline(fn *ir.Func) {
    59  	if ssaDump != "" && ssaDump == ir.FuncName(fn) {
    60  		ssaDumpInlined = append(ssaDumpInlined, fn)
    61  	}
    62  }
    63  
    64  func InitEnv() {
    65  	ssaDump = os.Getenv("GOSSAFUNC")
    66  	ssaDir = os.Getenv("GOSSADIR")
    67  	if ssaDump != "" {
    68  		if strings.HasSuffix(ssaDump, "+") {
    69  			ssaDump = ssaDump[:len(ssaDump)-1]
    70  			ssaDumpStdout = true
    71  		}
    72  		spl := strings.Split(ssaDump, ":")
    73  		if len(spl) > 1 {
    74  			ssaDump = spl[0]
    75  			ssaDumpCFG = spl[1]
    76  		}
    77  	}
    78  }
    79  
    80  func InitConfig() {
    81  	types_ := ssa.NewTypes()
    82  
    83  	if Arch.SoftFloat {
    84  		softfloatInit()
    85  	}
    86  
    87  	// Generate a few pointer types that are uncommon in the frontend but common in the backend.
    88  	// Caching is disabled in the backend, so generating these here avoids allocations.
    89  	_ = types.NewPtr(types.Types[types.TINTER])                             // *interface{}
    90  	_ = types.NewPtr(types.NewPtr(types.Types[types.TSTRING]))              // **string
    91  	_ = types.NewPtr(types.NewSlice(types.Types[types.TINTER]))             // *[]interface{}
    92  	_ = types.NewPtr(types.NewPtr(types.ByteType))                          // **byte
    93  	_ = types.NewPtr(types.NewSlice(types.ByteType))                        // *[]byte
    94  	_ = types.NewPtr(types.NewSlice(types.Types[types.TSTRING]))            // *[]string
    95  	_ = types.NewPtr(types.NewPtr(types.NewPtr(types.Types[types.TUINT8]))) // ***uint8
    96  	_ = types.NewPtr(types.Types[types.TINT16])                             // *int16
    97  	_ = types.NewPtr(types.Types[types.TINT64])                             // *int64
    98  	_ = types.NewPtr(types.ErrorType)                                       // *error
    99  	_ = types.NewPtr(reflectdata.MapType())                                 // *internal/runtime/maps.Map
   100  	_ = types.NewPtr(deferstruct())                                         // *runtime._defer
   101  	types.NewPtrCacheEnabled = false
   102  	ssaConfig = ssa.NewConfig(base.Ctxt.Arch.Name, *types_, base.Ctxt, base.Flag.N == 0, Arch.SoftFloat)
   103  	ssaConfig.Race = base.Flag.Race
   104  	ssaCaches = make([]ssa.Cache, base.Flag.LowerC)
   105  
   106  	// Set up some runtime functions we'll need to call.
   107  	ir.Syms.AssertE2I = typecheck.LookupRuntimeFunc("assertE2I")
   108  	ir.Syms.AssertE2I2 = typecheck.LookupRuntimeFunc("assertE2I2")
   109  	ir.Syms.CgoCheckMemmove = typecheck.LookupRuntimeFunc("cgoCheckMemmove")
   110  	ir.Syms.CgoCheckPtrWrite = typecheck.LookupRuntimeFunc("cgoCheckPtrWrite")
   111  	ir.Syms.CheckPtrAlignment = typecheck.LookupRuntimeFunc("checkptrAlignment")
   112  	ir.Syms.Deferproc = typecheck.LookupRuntimeFunc("deferproc")
   113  	ir.Syms.Deferprocat = typecheck.LookupRuntimeFunc("deferprocat")
   114  	ir.Syms.DeferprocStack = typecheck.LookupRuntimeFunc("deferprocStack")
   115  	ir.Syms.Deferreturn = typecheck.LookupRuntimeFunc("deferreturn")
   116  	ir.Syms.Duffcopy = typecheck.LookupRuntimeFunc("duffcopy")
   117  	ir.Syms.Duffzero = typecheck.LookupRuntimeFunc("duffzero")
   118  	ir.Syms.GCWriteBarrier[0] = typecheck.LookupRuntimeFunc("gcWriteBarrier1")
   119  	ir.Syms.GCWriteBarrier[1] = typecheck.LookupRuntimeFunc("gcWriteBarrier2")
   120  	ir.Syms.GCWriteBarrier[2] = typecheck.LookupRuntimeFunc("gcWriteBarrier3")
   121  	ir.Syms.GCWriteBarrier[3] = typecheck.LookupRuntimeFunc("gcWriteBarrier4")
   122  	ir.Syms.GCWriteBarrier[4] = typecheck.LookupRuntimeFunc("gcWriteBarrier5")
   123  	ir.Syms.GCWriteBarrier[5] = typecheck.LookupRuntimeFunc("gcWriteBarrier6")
   124  	ir.Syms.GCWriteBarrier[6] = typecheck.LookupRuntimeFunc("gcWriteBarrier7")
   125  	ir.Syms.GCWriteBarrier[7] = typecheck.LookupRuntimeFunc("gcWriteBarrier8")
   126  	ir.Syms.Goschedguarded = typecheck.LookupRuntimeFunc("goschedguarded")
   127  	ir.Syms.Growslice = typecheck.LookupRuntimeFunc("growslice")
   128  	ir.Syms.GrowsliceBuf = typecheck.LookupRuntimeFunc("growsliceBuf")
   129  	ir.Syms.GrowsliceBufNoAlias = typecheck.LookupRuntimeFunc("growsliceBufNoAlias")
   130  	ir.Syms.GrowsliceNoAlias = typecheck.LookupRuntimeFunc("growsliceNoAlias")
   131  	ir.Syms.MoveSlice = typecheck.LookupRuntimeFunc("moveSlice")
   132  	ir.Syms.MoveSliceNoScan = typecheck.LookupRuntimeFunc("moveSliceNoScan")
   133  	ir.Syms.MoveSliceNoCap = typecheck.LookupRuntimeFunc("moveSliceNoCap")
   134  	ir.Syms.MoveSliceNoCapNoScan = typecheck.LookupRuntimeFunc("moveSliceNoCapNoScan")
   135  	ir.Syms.InterfaceSwitch = typecheck.LookupRuntimeFunc("interfaceSwitch")
   136  	for i := 1; i < len(ir.Syms.MallocGCSmallNoScan); i++ {
   137  		ir.Syms.MallocGCSmallNoScan[i] = typecheck.LookupRuntimeFunc(fmt.Sprintf("mallocgcSmallNoScanSC%d", i))
   138  	}
   139  	for i := 1; i < len(ir.Syms.MallocGCSmallScanNoHeader); i++ {
   140  		ir.Syms.MallocGCSmallScanNoHeader[i] = typecheck.LookupRuntimeFunc(fmt.Sprintf("mallocgcSmallScanNoHeaderSC%d", i))
   141  	}
   142  	for i := 1; i < len(ir.Syms.MallocGCTiny); i++ {
   143  		ir.Syms.MallocGCTiny[i] = typecheck.LookupRuntimeFunc(fmt.Sprintf("mallocgcTinySize%d", i))
   144  	}
   145  	ir.Syms.MallocGC = typecheck.LookupRuntimeFunc("mallocgc")
   146  	ir.Syms.Memmove = typecheck.LookupRuntimeFunc("memmove")
   147  	ir.Syms.Memequal = typecheck.LookupRuntimeFunc("memequal")
   148  	ir.Syms.Msanread = typecheck.LookupRuntimeFunc("msanread")
   149  	ir.Syms.Msanwrite = typecheck.LookupRuntimeFunc("msanwrite")
   150  	ir.Syms.Msanmove = typecheck.LookupRuntimeFunc("msanmove")
   151  	ir.Syms.Asanread = typecheck.LookupRuntimeFunc("asanread")
   152  	ir.Syms.Asanwrite = typecheck.LookupRuntimeFunc("asanwrite")
   153  	ir.Syms.Newobject = typecheck.LookupRuntimeFunc("newobject")
   154  	ir.Syms.Newproc = typecheck.LookupRuntimeFunc("newproc")
   155  	ir.Syms.PanicBounds = typecheck.LookupRuntimeFunc("panicBounds")
   156  	ir.Syms.PanicExtend = typecheck.LookupRuntimeFunc("panicExtend")
   157  	ir.Syms.Panicdivide = typecheck.LookupRuntimeFunc("panicdivide")
   158  	ir.Syms.PanicdottypeE = typecheck.LookupRuntimeFunc("panicdottypeE")
   159  	ir.Syms.PanicdottypeI = typecheck.LookupRuntimeFunc("panicdottypeI")
   160  	ir.Syms.Panicnildottype = typecheck.LookupRuntimeFunc("panicnildottype")
   161  	ir.Syms.Panicoverflow = typecheck.LookupRuntimeFunc("panicoverflow")
   162  	ir.Syms.Panicshift = typecheck.LookupRuntimeFunc("panicshift")
   163  	ir.Syms.PanicSimdImm = typecheck.LookupRuntimeFunc("panicSimdImm")
   164  	ir.Syms.Racefuncenter = typecheck.LookupRuntimeFunc("racefuncenter")
   165  	ir.Syms.Racefuncexit = typecheck.LookupRuntimeFunc("racefuncexit")
   166  	ir.Syms.Raceread = typecheck.LookupRuntimeFunc("raceread")
   167  	ir.Syms.Racereadrange = typecheck.LookupRuntimeFunc("racereadrange")
   168  	ir.Syms.Racewrite = typecheck.LookupRuntimeFunc("racewrite")
   169  	ir.Syms.Racewriterange = typecheck.LookupRuntimeFunc("racewriterange")
   170  	ir.Syms.TypeAssert = typecheck.LookupRuntimeFunc("typeAssert")
   171  	ir.Syms.WBZero = typecheck.LookupRuntimeFunc("wbZero")
   172  	ir.Syms.WBMove = typecheck.LookupRuntimeFunc("wbMove")
   173  	ir.Syms.X86HasAVX = typecheck.LookupRuntimeVar("x86HasAVX")               // bool
   174  	ir.Syms.X86HasFMA = typecheck.LookupRuntimeVar("x86HasFMA")               // bool
   175  	ir.Syms.X86HasPOPCNT = typecheck.LookupRuntimeVar("x86HasPOPCNT")         // bool
   176  	ir.Syms.X86HasSSE41 = typecheck.LookupRuntimeVar("x86HasSSE41")           // bool
   177  	ir.Syms.ARMHasVFPv4 = typecheck.LookupRuntimeVar("armHasVFPv4")           // bool
   178  	ir.Syms.ARM64HasATOMICS = typecheck.LookupRuntimeVar("arm64HasATOMICS")   // bool
   179  	ir.Syms.Loong64HasLAMCAS = typecheck.LookupRuntimeVar("loong64HasLAMCAS") // bool
   180  	ir.Syms.Loong64HasLAM_BH = typecheck.LookupRuntimeVar("loong64HasLAM_BH") // bool
   181  	ir.Syms.Loong64HasLSX = typecheck.LookupRuntimeVar("loong64HasLSX")       // bool
   182  	ir.Syms.RISCV64HasZbb = typecheck.LookupRuntimeVar("riscv64HasZbb")       // bool
   183  	ir.Syms.Staticuint64s = typecheck.LookupRuntimeVar("staticuint64s")
   184  	ir.Syms.Typedmemmove = typecheck.LookupRuntimeFunc("typedmemmove")
   185  	ir.Syms.Udiv = typecheck.LookupRuntimeVar("udiv")                 // asm func with special ABI
   186  	ir.Syms.WriteBarrier = typecheck.LookupRuntimeVar("writeBarrier") // struct { bool; ... }
   187  	ir.Syms.Zerobase = typecheck.LookupRuntimeVar("zerobase")
   188  	ir.Syms.ZeroVal = typecheck.LookupRuntimeVar("zeroVal")
   189  
   190  	if Arch.LinkArch.Family == sys.Wasm {
   191  		BoundsCheckFunc[ssa.BoundsIndex] = typecheck.LookupRuntimeFunc("goPanicIndex")
   192  		BoundsCheckFunc[ssa.BoundsIndexU] = typecheck.LookupRuntimeFunc("goPanicIndexU")
   193  		BoundsCheckFunc[ssa.BoundsSliceAlen] = typecheck.LookupRuntimeFunc("goPanicSliceAlen")
   194  		BoundsCheckFunc[ssa.BoundsSliceAlenU] = typecheck.LookupRuntimeFunc("goPanicSliceAlenU")
   195  		BoundsCheckFunc[ssa.BoundsSliceAcap] = typecheck.LookupRuntimeFunc("goPanicSliceAcap")
   196  		BoundsCheckFunc[ssa.BoundsSliceAcapU] = typecheck.LookupRuntimeFunc("goPanicSliceAcapU")
   197  		BoundsCheckFunc[ssa.BoundsSliceB] = typecheck.LookupRuntimeFunc("goPanicSliceB")
   198  		BoundsCheckFunc[ssa.BoundsSliceBU] = typecheck.LookupRuntimeFunc("goPanicSliceBU")
   199  		BoundsCheckFunc[ssa.BoundsSlice3Alen] = typecheck.LookupRuntimeFunc("goPanicSlice3Alen")
   200  		BoundsCheckFunc[ssa.BoundsSlice3AlenU] = typecheck.LookupRuntimeFunc("goPanicSlice3AlenU")
   201  		BoundsCheckFunc[ssa.BoundsSlice3Acap] = typecheck.LookupRuntimeFunc("goPanicSlice3Acap")
   202  		BoundsCheckFunc[ssa.BoundsSlice3AcapU] = typecheck.LookupRuntimeFunc("goPanicSlice3AcapU")
   203  		BoundsCheckFunc[ssa.BoundsSlice3B] = typecheck.LookupRuntimeFunc("goPanicSlice3B")
   204  		BoundsCheckFunc[ssa.BoundsSlice3BU] = typecheck.LookupRuntimeFunc("goPanicSlice3BU")
   205  		BoundsCheckFunc[ssa.BoundsSlice3C] = typecheck.LookupRuntimeFunc("goPanicSlice3C")
   206  		BoundsCheckFunc[ssa.BoundsSlice3CU] = typecheck.LookupRuntimeFunc("goPanicSlice3CU")
   207  		BoundsCheckFunc[ssa.BoundsConvert] = typecheck.LookupRuntimeFunc("goPanicSliceConvert")
   208  	}
   209  
   210  	// Wasm (all asm funcs with special ABIs)
   211  	ir.Syms.WasmDiv = typecheck.LookupRuntimeVar("wasmDiv")
   212  	ir.Syms.WasmTruncS = typecheck.LookupRuntimeVar("wasmTruncS")
   213  	ir.Syms.WasmTruncU = typecheck.LookupRuntimeVar("wasmTruncU")
   214  	ir.Syms.SigPanic = typecheck.LookupRuntimeFunc("sigpanic")
   215  }
   216  
   217  func InitTables() {
   218  	initIntrinsics(nil)
   219  }
   220  
   221  // AbiForBodylessFuncStackMap returns the ABI for a bodyless function's stack map.
   222  // This is not necessarily the ABI used to call it.
   223  // Currently (1.17 dev) such a stack map is always ABI0;
   224  // any ABI wrapper that is present is nosplit, hence a precise
   225  // stack map is not needed there (the parameters survive only long
   226  // enough to call the wrapped assembly function).
   227  // This always returns a freshly copied ABI.
   228  func AbiForBodylessFuncStackMap(fn *ir.Func) *abi.ABIConfig {
   229  	return ssaConfig.ABI0.Copy() // No idea what races will result, be safe
   230  }
   231  
   232  // abiForFunc implements ABI policy for a function, but does not return a copy of the ABI.
   233  // Passing a nil function returns the default ABI based on experiment configuration.
   234  func abiForFunc(fn *ir.Func, abi0, abi1 *abi.ABIConfig) *abi.ABIConfig {
   235  	if buildcfg.Experiment.RegabiArgs {
   236  		// Select the ABI based on the function's defining ABI.
   237  		if fn == nil {
   238  			return abi1
   239  		}
   240  		switch fn.ABI {
   241  		case obj.ABI0:
   242  			return abi0
   243  		case obj.ABIInternal:
   244  			// TODO(austin): Clean up the nomenclature here.
   245  			// It's not clear that "abi1" is ABIInternal.
   246  			return abi1
   247  		}
   248  		base.Fatalf("function %v has unknown ABI %v", fn, fn.ABI)
   249  		panic("not reachable")
   250  	}
   251  
   252  	a := abi0
   253  	if fn != nil {
   254  		if fn.Pragma&ir.RegisterParams != 0 { // TODO(register args) remove after register abi is working
   255  			a = abi1
   256  		}
   257  	}
   258  	return a
   259  }
   260  
   261  // emitOpenDeferInfo emits FUNCDATA information about the defers in a function
   262  // that is using open-coded defers.  This funcdata is used to determine the active
   263  // defers in a function and execute those defers during panic processing.
   264  //
   265  // The funcdata is all encoded in varints (since values will almost always be less than
   266  // 128, but stack offsets could potentially be up to 2Gbyte). All "locations" (offsets)
   267  // for stack variables are specified as the number of bytes below varp (pointer to the
   268  // top of the local variables) for their starting address. The format is:
   269  //
   270  //   - Offset of the deferBits variable
   271  //   - Offset of the first closure slot (the rest are laid out consecutively).
   272  func (s *state) emitOpenDeferInfo() {
   273  	firstOffset := s.openDefers[0].closureNode.FrameOffset()
   274  
   275  	// Verify that cmpstackvarlt laid out the slots in order.
   276  	for i, r := range s.openDefers {
   277  		have := r.closureNode.FrameOffset()
   278  		want := firstOffset + int64(i)*int64(types.PtrSize)
   279  		if have != want {
   280  			base.FatalfAt(s.curfn.Pos(), "unexpected frame offset for open-coded defer slot #%v: have %v, want %v", i, have, want)
   281  		}
   282  	}
   283  
   284  	x := base.Ctxt.Lookup(s.curfn.LSym.Name + ".opendefer")
   285  	x.Set(obj.AttrContentAddressable, true)
   286  	x.Align = 1
   287  	s.curfn.LSym.Func().OpenCodedDeferInfo = x
   288  
   289  	off := 0
   290  	off = objw.Uvarint(x, off, uint64(-s.deferBitsTemp.FrameOffset()))
   291  	off = objw.Uvarint(x, off, uint64(-firstOffset))
   292  }
   293  
   294  // buildssa builds an SSA function for fn.
   295  // worker indicates which of the backend workers is doing the processing.
   296  func buildssa(fn *ir.Func, worker int, isPgoHot bool) *ssa.Func {
   297  	name := ir.FuncName(fn)
   298  
   299  	abiSelf := abiForFunc(fn, ssaConfig.ABI0, ssaConfig.ABI1)
   300  
   301  	printssa := false
   302  	// match either a simple name e.g. "(*Reader).Reset", package.name e.g. "compress/gzip.(*Reader).Reset", or subpackage name "gzip.(*Reader).Reset"
   303  	// optionally allows an ABI suffix specification in the GOSSAHASH, e.g. "(*Reader).Reset<0>" etc
   304  	if strings.Contains(ssaDump, name) { // in all the cases the function name is entirely contained within the GOSSAFUNC string.
   305  		nameOptABI := name
   306  		if l := len(ssaDump); l > 1 && ssaDump[l-2] == ',' { // ABI specification
   307  			nameOptABI = ssa.FuncNameABI(name, abiSelf.Which())
   308  		} else if strings.HasSuffix(ssaDump, ">") { // if they use the linker syntax instead....
   309  			l := len(ssaDump)
   310  			if l >= 3 && ssaDump[l-3] == '<' {
   311  				nameOptABI = ssa.FuncNameABI(name, abiSelf.Which())
   312  				ssaDump = ssaDump[:l-3] + "," + ssaDump[l-2:l-1]
   313  			}
   314  		}
   315  		pkgDotName := base.Ctxt.Pkgpath + "." + nameOptABI
   316  		printssa = nameOptABI == ssaDump || // "(*Reader).Reset"
   317  			pkgDotName == ssaDump || // "compress/gzip.(*Reader).Reset"
   318  			strings.HasSuffix(pkgDotName, ssaDump) && strings.HasSuffix(pkgDotName, "/"+ssaDump) // "gzip.(*Reader).Reset"
   319  	}
   320  
   321  	var astBuf *bytes.Buffer
   322  	if printssa {
   323  		astBuf = &bytes.Buffer{}
   324  		ir.FDumpList(astBuf, "buildssa-body", fn.Body)
   325  		if ssaDumpStdout {
   326  			fmt.Println("generating SSA for", name)
   327  			fmt.Print(astBuf.String())
   328  		}
   329  	}
   330  
   331  	var s state
   332  	s.pushLine(fn.Pos())
   333  	defer s.popLine()
   334  
   335  	s.hasdefer = fn.HasDefer()
   336  	if fn.Pragma&ir.CgoUnsafeArgs != 0 {
   337  		s.cgoUnsafeArgs = true
   338  	}
   339  	s.checkPtrEnabled = ir.ShouldCheckPtr(fn, 1)
   340  
   341  	if base.Flag.Cfg.Instrumenting && fn.Pragma&ir.Norace == 0 && !fn.Linksym().ABIWrapper() {
   342  		if !base.Flag.Race || !objabi.LookupPkgSpecial(fn.Sym().Pkg.Path).NoRaceFunc {
   343  			s.instrumentMemory = true
   344  			if base.Flag.Race {
   345  				s.instrumentEnterExit = true
   346  			}
   347  		}
   348  	}
   349  
   350  	fe := ssafn{
   351  		curfn: fn,
   352  		log:   printssa && ssaDumpStdout,
   353  	}
   354  	s.curfn = fn
   355  
   356  	cache := &ssaCaches[worker]
   357  	cache.Reset()
   358  
   359  	s.f = ssaConfig.NewFunc(&fe, cache)
   360  	s.config = ssaConfig
   361  	s.f.Type = fn.Type()
   362  	s.f.Name = name
   363  	s.f.PrintOrHtmlSSA = printssa
   364  	if fn.Pragma&ir.Nosplit != 0 {
   365  		s.f.NoSplit = true
   366  	}
   367  	s.f.ABI0 = ssaConfig.ABI0
   368  	s.f.ABI1 = ssaConfig.ABI1
   369  	s.f.ABIDefault = abiForFunc(nil, ssaConfig.ABI0, ssaConfig.ABI1)
   370  	s.f.ABISelf = abiSelf
   371  
   372  	s.panics = map[funcLine]*ssa.Block{}
   373  	s.softFloat = s.config.SoftFloat
   374  
   375  	// Allocate starting block
   376  	s.f.Entry = s.f.NewBlock(ssa.BlockPlain)
   377  	s.f.Entry.Pos = fn.Pos()
   378  	s.f.IsPgoHot = isPgoHot
   379  
   380  	if printssa {
   381  		ssaDF := ssaDumpFile
   382  		if ssaDir != "" {
   383  			ssaDF = filepath.Join(ssaDir, base.Ctxt.Pkgpath+"."+s.f.NameABI()+".html")
   384  			ssaD := filepath.Dir(ssaDF)
   385  			os.MkdirAll(ssaD, 0755)
   386  		}
   387  		s.f.HTMLWriter = ssa.NewHTMLWriter(ssaDF, s.f, ssaDumpCFG)
   388  		// TODO: generate and print a mapping from nodes to values and blocks
   389  		dumpSourcesColumn(s.f.HTMLWriter, fn)
   390  		s.f.HTMLWriter.WriteAST("AST", astBuf)
   391  	}
   392  
   393  	// Allocate starting values
   394  	s.labels = map[string]*ssaLabel{}
   395  	s.fwdVars = map[ir.Node]*ssa.Value{}
   396  	s.startmem = s.entryNewValue0(ssa.OpInitMem, types.TypeMem)
   397  
   398  	s.hasOpenDefers = base.Flag.N == 0 && s.hasdefer && !s.curfn.OpenCodedDeferDisallowed()
   399  	switch {
   400  	case base.Debug.NoOpenDefer != 0:
   401  		s.hasOpenDefers = false
   402  	case s.hasOpenDefers && (base.Ctxt.Flag_shared || base.Ctxt.Flag_dynlink) && base.Ctxt.Arch.Name == "386":
   403  		// Don't support open-coded defers for 386 ONLY when using shared
   404  		// libraries, because there is extra code (added by rewriteToUseGot())
   405  		// preceding the deferreturn/ret code that we don't track correctly.
   406  		//
   407  		// TODO this restriction can be removed given adjusted offset in computeDeferReturn in cmd/link/internal/ld/pcln.go
   408  		s.hasOpenDefers = false
   409  	}
   410  	if s.hasOpenDefers && s.instrumentEnterExit {
   411  		// Skip doing open defers if we need to instrument function
   412  		// returns for the race detector, since we will not generate that
   413  		// code in the case of the extra deferreturn/ret segment.
   414  		s.hasOpenDefers = false
   415  	}
   416  	if s.hasOpenDefers {
   417  		// Similarly, skip if there are any heap-allocated result
   418  		// parameters that need to be copied back to their stack slots.
   419  		for _, f := range s.curfn.Type().Results() {
   420  			if !f.Nname.(*ir.Name).OnStack() {
   421  				s.hasOpenDefers = false
   422  				break
   423  			}
   424  		}
   425  	}
   426  	if s.hasOpenDefers &&
   427  		s.curfn.NumReturns*s.curfn.NumDefers > 15 {
   428  		// Since we are generating defer calls at every exit for
   429  		// open-coded defers, skip doing open-coded defers if there are
   430  		// too many returns (especially if there are multiple defers).
   431  		// Open-coded defers are most important for improving performance
   432  		// for smaller functions (which don't have many returns).
   433  		s.hasOpenDefers = false
   434  	}
   435  
   436  	s.sp = s.entryNewValue0(ssa.OpSP, types.Types[types.TUINTPTR]) // TODO: use generic pointer type (unsafe.Pointer?) instead
   437  	s.sb = s.entryNewValue0(ssa.OpSB, types.Types[types.TUINTPTR])
   438  
   439  	s.startBlock(s.f.Entry)
   440  	s.vars[memVar] = s.startmem
   441  	if s.hasOpenDefers {
   442  		// Create the deferBits variable and stack slot.  deferBits is a
   443  		// bitmask showing which of the open-coded defers in this function
   444  		// have been activated.
   445  		deferBitsTemp := typecheck.TempAt(src.NoXPos, s.curfn, types.Types[types.TUINT8])
   446  		deferBitsTemp.SetAddrtaken(true)
   447  		s.deferBitsTemp = deferBitsTemp
   448  		// For this value, AuxInt is initialized to zero by default
   449  		startDeferBits := s.entryNewValue0(ssa.OpConst8, types.Types[types.TUINT8])
   450  		s.vars[deferBitsVar] = startDeferBits
   451  		s.deferBitsAddr = s.addr(deferBitsTemp)
   452  		s.store(types.Types[types.TUINT8], s.deferBitsAddr, startDeferBits)
   453  		// Make sure that the deferBits stack slot is kept alive (for use
   454  		// by panics) and stores to deferBits are not eliminated, even if
   455  		// all checking code on deferBits in the function exit can be
   456  		// eliminated, because the defer statements were all
   457  		// unconditional.
   458  		s.vars[memVar] = s.newValue1Apos(ssa.OpVarLive, types.TypeMem, deferBitsTemp, s.mem(), false)
   459  	}
   460  
   461  	var params *abi.ABIParamResultInfo
   462  	params = s.f.ABISelf.ABIAnalyze(fn.Type(), true)
   463  
   464  	// The backend's stackframe pass prunes away entries from the fn's
   465  	// Dcl list, including PARAMOUT nodes that correspond to output
   466  	// params passed in registers. Walk the Dcl list and capture these
   467  	// nodes to a side list, so that we'll have them available during
   468  	// DWARF-gen later on. See issue 48573 for more details.
   469  	var debugInfo ssa.FuncDebug
   470  	for _, n := range fn.Dcl {
   471  		if n.Class == ir.PPARAMOUT && n.IsOutputParamInRegisters() {
   472  			debugInfo.RegOutputParams = append(debugInfo.RegOutputParams, n)
   473  		}
   474  	}
   475  	fn.DebugInfo = &debugInfo
   476  
   477  	// Generate addresses of local declarations
   478  	s.decladdrs = map[*ir.Name]*ssa.Value{}
   479  	for _, n := range fn.Dcl {
   480  		switch n.Class {
   481  		case ir.PPARAM:
   482  			// Be aware that blank and unnamed input parameters will not appear here, but do appear in the type
   483  			s.decladdrs[n] = s.entryNewValue2A(ssa.OpLocalAddr, types.NewPtr(n.Type()), n, s.sp, s.startmem)
   484  		case ir.PPARAMOUT:
   485  			s.decladdrs[n] = s.entryNewValue2A(ssa.OpLocalAddr, types.NewPtr(n.Type()), n, s.sp, s.startmem)
   486  		case ir.PAUTO:
   487  			// processed at each use, to prevent Addr coming
   488  			// before the decl.
   489  		default:
   490  			s.Fatalf("local variable with class %v unimplemented", n.Class)
   491  		}
   492  	}
   493  
   494  	s.f.OwnAux = ssa.OwnAuxCall(fn.LSym, params)
   495  
   496  	// Populate SSAable arguments.
   497  	for _, n := range fn.Dcl {
   498  		if n.Class == ir.PPARAM {
   499  			if s.canSSA(n) {
   500  				v := s.newValue0A(ssa.OpArg, n.Type(), n)
   501  				s.vars[n] = v
   502  				s.addNamedValue(n, v) // This helps with debugging information, not needed for compilation itself.
   503  			} else { // address was taken AND/OR too large for SSA
   504  				paramAssignment := ssa.ParamAssignmentForArgName(s.f, n)
   505  				if len(paramAssignment.Registers) > 0 {
   506  					if ssa.CanSSA(n.Type()) { // SSA-able type, so address was taken -- receive value in OpArg, DO NOT bind to var, store immediately to memory.
   507  						v := s.newValue0A(ssa.OpArg, n.Type(), n)
   508  						s.store(n.Type(), s.decladdrs[n], v)
   509  					} else { // Too big for SSA.
   510  						// Brute force, and early, do a bunch of stores from registers
   511  						// Note that expand calls knows about this and doesn't trouble itself with larger-than-SSA-able Args in registers.
   512  						s.storeParameterRegsToStack(s.f.ABISelf, paramAssignment, n, s.decladdrs[n], false)
   513  					}
   514  				}
   515  			}
   516  		}
   517  	}
   518  
   519  	// Populate closure variables.
   520  	if fn.Needctxt() {
   521  		clo := s.entryNewValue0(ssa.OpGetClosurePtr, s.f.Config.Types.BytePtr)
   522  		if fn.RangeParent != nil && base.Flag.N != 0 {
   523  			// For a range body closure, keep its closure pointer live on the
   524  			// stack with a special name, so the debugger can look for it and
   525  			// find the parent frame.
   526  			sym := &types.Sym{Name: ".closureptr", Pkg: types.LocalPkg}
   527  			cloSlot := s.curfn.NewLocal(src.NoXPos, sym, s.f.Config.Types.BytePtr)
   528  			cloSlot.SetUsed(true)
   529  			cloSlot.SetEsc(ir.EscNever)
   530  			cloSlot.SetAddrtaken(true)
   531  			s.f.CloSlot = cloSlot
   532  			s.vars[memVar] = s.newValue1Apos(ssa.OpVarDef, types.TypeMem, cloSlot, s.mem(), false)
   533  			addr := s.addr(cloSlot)
   534  			s.store(s.f.Config.Types.BytePtr, addr, clo)
   535  			// Keep it from being dead-store eliminated.
   536  			s.vars[memVar] = s.newValue1Apos(ssa.OpVarLive, types.TypeMem, cloSlot, s.mem(), false)
   537  		}
   538  		csiter := typecheck.NewClosureStructIter(fn.ClosureVars)
   539  		for {
   540  			n, typ, offset := csiter.Next()
   541  			if n == nil {
   542  				break
   543  			}
   544  
   545  			ptr := s.newValue1I(ssa.OpOffPtr, types.NewPtr(typ), offset, clo)
   546  
   547  			// If n is a small variable captured by value, promote
   548  			// it to PAUTO so it can be converted to SSA.
   549  			//
   550  			// Note: While we never capture a variable by value if
   551  			// the user took its address, we may have generated
   552  			// runtime calls that did (#43701). Since we don't
   553  			// convert Addrtaken variables to SSA anyway, no point
   554  			// in promoting them either.
   555  			if n.Byval() && !n.Addrtaken() && ssa.CanSSA(n.Type()) {
   556  				n.Class = ir.PAUTO
   557  				fn.Dcl = append(fn.Dcl, n)
   558  				s.assign(n, s.load(n.Type(), ptr), false, 0)
   559  				continue
   560  			}
   561  
   562  			if !n.Byval() {
   563  				ptr = s.load(typ, ptr)
   564  			}
   565  			s.setHeapaddr(fn.Pos(), n, ptr)
   566  		}
   567  	}
   568  
   569  	// Convert the AST-based IR to the SSA-based IR
   570  	if s.instrumentEnterExit {
   571  		s.rtcall(ir.Syms.Racefuncenter, true, nil, s.newValue0(ssa.OpGetCallerPC, types.Types[types.TUINTPTR]))
   572  	}
   573  	s.zeroResults()
   574  	s.paramsToHeap()
   575  	s.stmtList(fn.Body)
   576  
   577  	// fallthrough to exit
   578  	if s.curBlock != nil {
   579  		s.pushLine(fn.Endlineno)
   580  		s.exit()
   581  		s.popLine()
   582  	}
   583  
   584  	for _, b := range s.f.Blocks {
   585  		if b.Pos != src.NoXPos {
   586  			s.updateUnsetPredPos(b)
   587  		}
   588  	}
   589  
   590  	s.f.HTMLWriter.WritePhase("before insert phis", "before insert phis")
   591  
   592  	s.insertPhis()
   593  
   594  	// Main call to ssa package to compile function
   595  	ssa.Compile(s.f)
   596  
   597  	fe.AllocFrame(s.f)
   598  
   599  	if len(s.openDefers) != 0 {
   600  		s.emitOpenDeferInfo()
   601  	}
   602  
   603  	// Record incoming parameter spill information for morestack calls emitted in the assembler.
   604  	// This is done here, using all the parameters (used, partially used, and unused) because
   605  	// it mimics the behavior of the former ABI (everything stored) and because it's not 100%
   606  	// clear if naming conventions are respected in autogenerated code.
   607  	// TODO figure out exactly what's unused, don't spill it. Make liveness fine-grained, also.
   608  	for _, p := range params.InParams() {
   609  		typs, offs := p.RegisterTypesAndOffsets()
   610  		if len(offs) < len(typs) {
   611  			s.Fatalf("len(offs)=%d < len(typs)=%d, params=\n%s", len(offs), len(typs), params)
   612  		}
   613  		for i, t := range typs {
   614  			o := offs[i]                // offset within parameter
   615  			fo := p.FrameOffset(params) // offset of parameter in frame
   616  			reg := ssa.ObjRegForAbiReg(p.Registers[i], s.f.Config)
   617  			s.f.RegArgs = append(s.f.RegArgs, ssa.Spill{Reg: reg, Offset: fo + o, Type: t})
   618  		}
   619  	}
   620  
   621  	return s.f
   622  }
   623  
   624  func (s *state) storeParameterRegsToStack(abi *abi.ABIConfig, paramAssignment *abi.ABIParamAssignment, n *ir.Name, addr *ssa.Value, pointersOnly bool) {
   625  	typs, offs := paramAssignment.RegisterTypesAndOffsets()
   626  	for i, t := range typs {
   627  		if pointersOnly && !t.IsPtrShaped() {
   628  			continue
   629  		}
   630  		r := paramAssignment.Registers[i]
   631  		o := offs[i]
   632  		op, reg := ssa.ArgOpAndRegisterFor(r, abi)
   633  		aux := &ssa.AuxNameOffset{Name: n, Offset: o}
   634  		v := s.newValue0I(op, t, reg)
   635  		v.Aux = aux
   636  		p := s.newValue1I(ssa.OpOffPtr, types.NewPtr(t), o, addr)
   637  		s.store(t, p, v)
   638  	}
   639  }
   640  
   641  // zeroResults zeros the return values at the start of the function.
   642  // We need to do this very early in the function.  Defer might stop a
   643  // panic and show the return values as they exist at the time of
   644  // panic.  For precise stacks, the garbage collector assumes results
   645  // are always live, so we need to zero them before any allocations,
   646  // even allocations to move params/results to the heap.
   647  func (s *state) zeroResults() {
   648  	for _, f := range s.curfn.Type().Results() {
   649  		n := f.Nname.(*ir.Name)
   650  		if !n.OnStack() {
   651  			// The local which points to the return value is the
   652  			// thing that needs zeroing. This is already handled
   653  			// by a Needzero annotation in plive.go:(*liveness).epilogue.
   654  			continue
   655  		}
   656  		// Zero the stack location containing f.
   657  		if typ := n.Type(); ssa.CanSSA(typ) {
   658  			s.assign(n, s.zeroVal(typ), false, 0)
   659  		} else {
   660  			if typ.HasPointers() || ssa.IsMergeCandidate(n) {
   661  				s.vars[memVar] = s.newValue1A(ssa.OpVarDef, types.TypeMem, n, s.mem())
   662  			}
   663  			s.zero(n.Type(), s.decladdrs[n])
   664  		}
   665  	}
   666  }
   667  
   668  // paramsToHeap produces code to allocate memory for heap-escaped parameters
   669  // and to copy non-result parameters' values from the stack.
   670  func (s *state) paramsToHeap() {
   671  	do := func(params []*types.Field) {
   672  		for _, f := range params {
   673  			if f.Nname == nil {
   674  				continue // anonymous or blank parameter
   675  			}
   676  			n := f.Nname.(*ir.Name)
   677  			if ir.IsBlank(n) || n.OnStack() {
   678  				continue
   679  			}
   680  			s.newHeapaddr(n)
   681  			if n.Class == ir.PPARAM {
   682  				s.move(n.Type(), s.expr(n.Heapaddr), s.decladdrs[n])
   683  			}
   684  		}
   685  	}
   686  
   687  	typ := s.curfn.Type()
   688  	do(typ.Recvs())
   689  	do(typ.Params())
   690  	do(typ.Results())
   691  }
   692  
   693  // allocSizeAndAlign returns the size and alignment of t.
   694  // Normally just t.Size() and t.Alignment(), but there
   695  // is a special case to handle 64-bit atomics on 32-bit systems.
   696  func allocSizeAndAlign(t *types.Type) (int64, int64) {
   697  	size, align := t.Size(), t.Alignment()
   698  	if types.PtrSize == 4 && align == 4 && size >= 8 {
   699  		// For 64-bit atomics on 32-bit systems.
   700  		size = types.RoundUp(size, 8)
   701  		align = 8
   702  	}
   703  	return size, align
   704  }
   705  func allocSize(t *types.Type) int64 {
   706  	size, _ := allocSizeAndAlign(t)
   707  	return size
   708  }
   709  func allocAlign(t *types.Type) int64 {
   710  	_, align := allocSizeAndAlign(t)
   711  	return align
   712  }
   713  
   714  // newHeapaddr allocates heap memory for n and sets its heap address.
   715  func (s *state) newHeapaddr(n *ir.Name) {
   716  	size := allocSize(n.Type())
   717  	if n.Type().HasPointers() || size >= maxAggregatedHeapAllocation || size == 0 {
   718  		s.setHeapaddr(n.Pos(), n, s.newObject(n.Type()))
   719  		return
   720  	}
   721  
   722  	// Do we have room together with our pending allocations?
   723  	// If not, flush all the current ones.
   724  	var used int64
   725  	for _, v := range s.pendingHeapAllocations {
   726  		used += allocSize(v.Type.Elem())
   727  	}
   728  	if used+size > maxAggregatedHeapAllocation {
   729  		s.flushPendingHeapAllocations()
   730  	}
   731  
   732  	var allocCall *ssa.Value // (SelectN [0] (call of runtime.newobject))
   733  	if len(s.pendingHeapAllocations) == 0 {
   734  		// Make an allocation, but the type being allocated is just
   735  		// the first pending object. We will come back and update it
   736  		// later if needed.
   737  		allocCall = s.newObjectNonSpecialized(n.Type(), nil)
   738  	} else {
   739  		allocCall = s.pendingHeapAllocations[0].Args[0]
   740  	}
   741  	// v is an offset to the shared allocation. Offsets are dummy 0s for now.
   742  	v := s.newValue1I(ssa.OpOffPtr, n.Type().PtrTo(), 0, allocCall)
   743  
   744  	// Add to list of pending allocations.
   745  	s.pendingHeapAllocations = append(s.pendingHeapAllocations, v)
   746  
   747  	// Finally, record for posterity.
   748  	s.setHeapaddr(n.Pos(), n, v)
   749  }
   750  
   751  func (s *state) flushPendingHeapAllocations() {
   752  	pending := s.pendingHeapAllocations
   753  	if len(pending) == 0 {
   754  		return // nothing to do
   755  	}
   756  	s.pendingHeapAllocations = nil // reset state
   757  	ptr := pending[0].Args[0]      // The SelectN [0] op
   758  	call := ptr.Args[0]            // The runtime.newobject call
   759  
   760  	if len(pending) == 1 {
   761  		// Just a single object, do a standard allocation.
   762  		v := pending[0]
   763  		v.Op = ssa.OpCopy // instead of OffPtr [0]
   764  		return
   765  	}
   766  
   767  	// Sort in decreasing alignment.
   768  	// This way we never have to worry about padding.
   769  	// (Stable not required; just cleaner to keep program order among equal alignments.)
   770  	slices.SortStableFunc(pending, func(x, y *ssa.Value) int {
   771  		return cmp.Compare(allocAlign(y.Type.Elem()), allocAlign(x.Type.Elem()))
   772  	})
   773  
   774  	// Figure out how much data we need allocate.
   775  	var size int64
   776  	for _, v := range pending {
   777  		v.AuxInt = size // Adjust OffPtr to the right value while we are here.
   778  		size += allocSize(v.Type.Elem())
   779  	}
   780  	align := allocAlign(pending[0].Type.Elem())
   781  	size = types.RoundUp(size, align)
   782  
   783  	// Convert newObject call to a mallocgc call.
   784  	args := []*ssa.Value{
   785  		s.constInt(types.Types[types.TUINTPTR], size),
   786  		s.constNil(call.Args[0].Type), // a nil *runtime._type
   787  		s.constBool(true),             // needZero TODO: false is ok?
   788  		call.Args[1],                  // memory
   789  	}
   790  	mallocSym := ir.Syms.MallocGC
   791  	if specialMallocSym := s.specializedMallocSym(size, false); specialMallocSym != nil {
   792  		mallocSym = specialMallocSym
   793  	}
   794  	call.Aux = ssa.StaticAuxCall(mallocSym, s.f.ABIDefault.ABIAnalyzeTypes(
   795  		[]*types.Type{args[0].Type, args[1].Type, args[2].Type},
   796  		[]*types.Type{types.Types[types.TUNSAFEPTR]},
   797  	))
   798  	call.AuxInt = 4 * s.config.PtrSize // arg+results size, uintptr/ptr/bool/ptr
   799  	call.SetArgs4(args[0], args[1], args[2], args[3])
   800  	// TODO: figure out how to pass alignment to runtime
   801  
   802  	call.Type = types.NewTuple(types.Types[types.TUNSAFEPTR], types.TypeMem)
   803  	ptr.Type = types.Types[types.TUNSAFEPTR]
   804  }
   805  
   806  func (s *state) specializedMallocSym(size int64, hasPointers bool) *obj.LSym {
   807  	if !s.sizeSpecializedMallocEnabled() {
   808  		return nil
   809  	}
   810  	ptrSize := s.config.PtrSize
   811  	ptrBits := ptrSize * 8
   812  	minSizeForMallocHeader := ptrSize * ptrBits
   813  	heapBitsInSpan := size <= minSizeForMallocHeader
   814  	if !heapBitsInSpan {
   815  		return nil
   816  	}
   817  	divRoundUp := func(n, a uintptr) uintptr { return (n + a - 1) / a }
   818  	sizeClass := gc.SizeToSizeClass8[divRoundUp(uintptr(size), gc.SmallSizeDiv)]
   819  	if hasPointers {
   820  		return ir.Syms.MallocGCSmallScanNoHeader[sizeClass]
   821  	}
   822  	if size < gc.TinySize {
   823  		return ir.Syms.MallocGCTiny[size]
   824  	}
   825  	return ir.Syms.MallocGCSmallNoScan[sizeClass]
   826  }
   827  
   828  func (s *state) sizeSpecializedMallocEnabled() bool {
   829  	if base.Flag.CompilingRuntime {
   830  		// The compiler forces the values of the asan, msan, and race flags to false if
   831  		// we're compiling the runtime, so we lose the information about whether we're
   832  		// building in asan, msan, or race mode. Because the specialized functions don't
   833  		// work in that mode, just turn if off in that case.
   834  		// TODO(matloob): Save the information about whether the flags were passed in
   835  		// originally so we can turn off size specialized malloc in that case instead
   836  		// using Instrumenting below. Then we can remove this condition.
   837  		return false
   838  	}
   839  
   840  	return buildcfg.Experiment.SizeSpecializedMalloc && !base.Flag.Cfg.Instrumenting
   841  }
   842  
   843  // setHeapaddr allocates a new PAUTO variable to store ptr (which must be non-nil)
   844  // and then sets it as n's heap address.
   845  func (s *state) setHeapaddr(pos src.XPos, n *ir.Name, ptr *ssa.Value) {
   846  	if !ptr.Type.IsPtr() || !types.Identical(n.Type(), ptr.Type.Elem()) {
   847  		base.FatalfAt(n.Pos(), "setHeapaddr %L with type %v", n, ptr.Type)
   848  	}
   849  
   850  	// Declare variable to hold address.
   851  	sym := &types.Sym{Name: "&" + n.Sym().Name, Pkg: types.LocalPkg}
   852  	addr := s.curfn.NewLocal(pos, sym, types.NewPtr(n.Type()))
   853  	addr.SetUsed(true)
   854  	types.CalcSize(addr.Type())
   855  
   856  	if n.Class == ir.PPARAMOUT {
   857  		addr.SetIsOutputParamHeapAddr(true)
   858  	}
   859  
   860  	n.Heapaddr = addr
   861  	s.assign(addr, ptr, false, 0)
   862  }
   863  
   864  // newObject returns an SSA value denoting new(typ).
   865  func (s *state) newObject(typ *types.Type) *ssa.Value {
   866  	if typ.Size() == 0 {
   867  		return s.newValue1A(ssa.OpAddr, types.NewPtr(typ), ir.Syms.Zerobase, s.sb)
   868  	}
   869  	rtype := s.reflectType(typ)
   870  	if specialMallocSym := s.specializedMallocSym(typ.Size(), typ.HasPointers()); specialMallocSym != nil {
   871  		return s.rtcall(specialMallocSym, true, []*types.Type{types.NewPtr(typ)},
   872  			s.constInt(types.Types[types.TUINTPTR], typ.Size()),
   873  			rtype,
   874  			s.constBool(true),
   875  		)[0]
   876  	}
   877  	return s.rtcall(ir.Syms.Newobject, true, []*types.Type{types.NewPtr(typ)}, rtype)[0]
   878  }
   879  
   880  // newObjectNonSpecialized returns an SSA value denoting new(typ). It does
   881  // not produce size-specialized malloc functions.
   882  func (s *state) newObjectNonSpecialized(typ *types.Type, rtype *ssa.Value) *ssa.Value {
   883  	if typ.Size() == 0 {
   884  		return s.newValue1A(ssa.OpAddr, types.NewPtr(typ), ir.Syms.Zerobase, s.sb)
   885  	}
   886  	if rtype == nil {
   887  		rtype = s.reflectType(typ)
   888  	}
   889  	return s.rtcall(ir.Syms.Newobject, true, []*types.Type{types.NewPtr(typ)}, rtype)[0]
   890  }
   891  
   892  func (s *state) checkPtrAlignment(n *ir.ConvExpr, v *ssa.Value, count *ssa.Value) {
   893  	if !n.Type().IsPtr() {
   894  		s.Fatalf("expected pointer type: %v", n.Type())
   895  	}
   896  	elem, rtypeExpr := n.Type().Elem(), n.ElemRType
   897  	if count != nil {
   898  		if !elem.IsArray() {
   899  			s.Fatalf("expected array type: %v", elem)
   900  		}
   901  		elem, rtypeExpr = elem.Elem(), n.ElemElemRType
   902  	}
   903  	size := elem.Size()
   904  	// Casting from larger type to smaller one is ok, so for smallest type, do nothing.
   905  	if elem.Alignment() == 1 && (size == 0 || size == 1 || count == nil) {
   906  		return
   907  	}
   908  	if count == nil {
   909  		count = s.constInt(types.Types[types.TUINTPTR], 1)
   910  	}
   911  	if count.Type.Size() != s.config.PtrSize {
   912  		s.Fatalf("expected count fit to a uintptr size, have: %d, want: %d", count.Type.Size(), s.config.PtrSize)
   913  	}
   914  	var rtype *ssa.Value
   915  	if rtypeExpr != nil {
   916  		rtype = s.expr(rtypeExpr)
   917  	} else {
   918  		rtype = s.reflectType(elem)
   919  	}
   920  	s.rtcall(ir.Syms.CheckPtrAlignment, true, nil, v, rtype, count)
   921  }
   922  
   923  // reflectType returns an SSA value representing a pointer to typ's
   924  // reflection type descriptor.
   925  func (s *state) reflectType(typ *types.Type) *ssa.Value {
   926  	// TODO(mdempsky): Make this Fatalf under Unified IR; frontend needs
   927  	// to supply RType expressions.
   928  	lsym := reflectdata.TypeLinksym(typ)
   929  	return s.entryNewValue1A(ssa.OpAddr, types.NewPtr(types.Types[types.TUINT8]), lsym, s.sb)
   930  }
   931  
   932  func dumpSourcesColumn(writer *ssa.HTMLWriter, fn *ir.Func) {
   933  	// Read sources of target function fn.
   934  	fname := base.Ctxt.PosTable.Pos(fn.Pos()).Filename()
   935  	targetFn, err := readFuncLines(fname, fn.Pos().Line(), fn.Endlineno.Line())
   936  	if err != nil {
   937  		writer.Logf("cannot read sources for function %v: %v", fn, err)
   938  	}
   939  
   940  	// Read sources of inlined functions.
   941  	var inlFns []*ssa.FuncLines
   942  	for _, fi := range ssaDumpInlined {
   943  		elno := fi.Endlineno
   944  		fname := base.Ctxt.PosTable.Pos(fi.Pos()).Filename()
   945  		fnLines, err := readFuncLines(fname, fi.Pos().Line(), elno.Line())
   946  		if err != nil {
   947  			writer.Logf("cannot read sources for inlined function %v: %v", fi, err)
   948  			continue
   949  		}
   950  		inlFns = append(inlFns, fnLines)
   951  	}
   952  
   953  	slices.SortFunc(inlFns, ssa.ByTopoCmp)
   954  	if targetFn != nil {
   955  		inlFns = append([]*ssa.FuncLines{targetFn}, inlFns...)
   956  	}
   957  
   958  	writer.WriteSources("sources", inlFns)
   959  }
   960  
   961  func readFuncLines(file string, start, end uint) (*ssa.FuncLines, error) {
   962  	f, err := os.Open(os.ExpandEnv(file))
   963  	if err != nil {
   964  		return nil, err
   965  	}
   966  	defer f.Close()
   967  	var lines []string
   968  	ln := uint(1)
   969  	scanner := bufio.NewScanner(f)
   970  	for scanner.Scan() && ln <= end {
   971  		if ln >= start {
   972  			lines = append(lines, scanner.Text())
   973  		}
   974  		ln++
   975  	}
   976  	return &ssa.FuncLines{Filename: file, StartLineno: start, Lines: lines}, nil
   977  }
   978  
   979  // updateUnsetPredPos propagates the earliest-value position information for b
   980  // towards all of b's predecessors that need a position, and recurs on that
   981  // predecessor if its position is updated. B should have a non-empty position.
   982  func (s *state) updateUnsetPredPos(b *ssa.Block) {
   983  	if b.Pos == src.NoXPos {
   984  		s.Fatalf("Block %s should have a position", b)
   985  	}
   986  	bestPos := src.NoXPos
   987  	for _, e := range b.Preds {
   988  		p := e.Block()
   989  		if !p.LackingPos() {
   990  			continue
   991  		}
   992  		if bestPos == src.NoXPos {
   993  			bestPos = b.Pos
   994  			for _, v := range b.Values {
   995  				if v.LackingPos() {
   996  					continue
   997  				}
   998  				if v.Pos != src.NoXPos {
   999  					// Assume values are still in roughly textual order;
  1000  					// TODO: could also seek minimum position?
  1001  					bestPos = v.Pos
  1002  					break
  1003  				}
  1004  			}
  1005  		}
  1006  		p.Pos = bestPos
  1007  		s.updateUnsetPredPos(p) // We do not expect long chains of these, thus recursion is okay.
  1008  	}
  1009  }
  1010  
  1011  // Information about each open-coded defer.
  1012  type openDeferInfo struct {
  1013  	// The node representing the call of the defer
  1014  	n *ir.CallExpr
  1015  	// If defer call is closure call, the address of the argtmp where the
  1016  	// closure is stored.
  1017  	closure *ssa.Value
  1018  	// The node representing the argtmp where the closure is stored - used for
  1019  	// function, method, or interface call, to store a closure that panic
  1020  	// processing can use for this defer.
  1021  	closureNode *ir.Name
  1022  }
  1023  
  1024  type state struct {
  1025  	// configuration (arch) information
  1026  	config *ssa.Config
  1027  
  1028  	// function we're building
  1029  	f *ssa.Func
  1030  
  1031  	// Node for function
  1032  	curfn *ir.Func
  1033  
  1034  	// labels in f
  1035  	labels map[string]*ssaLabel
  1036  
  1037  	// unlabeled break and continue statement tracking
  1038  	breakTo    *ssa.Block // current target for plain break statement
  1039  	continueTo *ssa.Block // current target for plain continue statement
  1040  
  1041  	// current location where we're interpreting the AST
  1042  	curBlock *ssa.Block
  1043  
  1044  	// variable assignments in the current block (map from variable symbol to ssa value)
  1045  	// *Node is the unique identifier (an ONAME Node) for the variable.
  1046  	// TODO: keep a single varnum map, then make all of these maps slices instead?
  1047  	vars map[ir.Node]*ssa.Value
  1048  
  1049  	// fwdVars are variables that are used before they are defined in the current block.
  1050  	// This map exists just to coalesce multiple references into a single FwdRef op.
  1051  	// *Node is the unique identifier (an ONAME Node) for the variable.
  1052  	fwdVars map[ir.Node]*ssa.Value
  1053  
  1054  	// all defined variables at the end of each block. Indexed by block ID.
  1055  	defvars []map[ir.Node]*ssa.Value
  1056  
  1057  	// addresses of PPARAM and PPARAMOUT variables on the stack.
  1058  	decladdrs map[*ir.Name]*ssa.Value
  1059  
  1060  	// starting values. Memory, stack pointer, and globals pointer
  1061  	startmem *ssa.Value
  1062  	sp       *ssa.Value
  1063  	sb       *ssa.Value
  1064  	// value representing address of where deferBits autotmp is stored
  1065  	deferBitsAddr *ssa.Value
  1066  	deferBitsTemp *ir.Name
  1067  
  1068  	// line number stack. The current line number is top of stack
  1069  	line []src.XPos
  1070  	// the last line number processed; it may have been popped
  1071  	lastPos src.XPos
  1072  
  1073  	// list of panic calls by function name and line number.
  1074  	// Used to deduplicate panic calls.
  1075  	panics map[funcLine]*ssa.Block
  1076  
  1077  	cgoUnsafeArgs       bool
  1078  	hasdefer            bool // whether the function contains a defer statement
  1079  	softFloat           bool
  1080  	hasOpenDefers       bool // whether we are doing open-coded defers
  1081  	checkPtrEnabled     bool // whether to insert checkptr instrumentation
  1082  	instrumentEnterExit bool // whether to instrument function enter/exit
  1083  	instrumentMemory    bool // whether to instrument memory operations
  1084  
  1085  	// If doing open-coded defers, list of info about the defer calls in
  1086  	// scanning order. Hence, at exit we should run these defers in reverse
  1087  	// order of this list
  1088  	openDefers []*openDeferInfo
  1089  	// For open-coded defers, this is the beginning and end blocks of the last
  1090  	// defer exit code that we have generated so far. We use these to share
  1091  	// code between exits if the shareDeferExits option (disabled by default)
  1092  	// is on.
  1093  	lastDeferExit       *ssa.Block // Entry block of last defer exit code we generated
  1094  	lastDeferFinalBlock *ssa.Block // Final block of last defer exit code we generated
  1095  	lastDeferCount      int        // Number of defers encountered at that point
  1096  
  1097  	prevCall *ssa.Value // the previous call; use this to tie results to the call op.
  1098  
  1099  	// List of allocations in the current block that are still pending.
  1100  	// They are all (OffPtr (Select0 (runtime call))) and have the correct types,
  1101  	// but the offsets are not set yet, and the type of the runtime call is also not final.
  1102  	pendingHeapAllocations []*ssa.Value
  1103  
  1104  	// First argument of append calls that could be stack allocated.
  1105  	appendTargets map[ir.Node]bool
  1106  
  1107  	// Block starting position, indexed by block id.
  1108  	blockStarts []src.XPos
  1109  
  1110  	// Information for stack allocation. Indexed by the first argument
  1111  	// to an append call. Normally a slice-typed variable, but not always.
  1112  	backingStores map[ir.Node]*backingStoreInfo
  1113  }
  1114  
  1115  type backingStoreInfo struct {
  1116  	// Size of backing store array (in elements)
  1117  	K int64
  1118  	// Stack-allocated backing store variable.
  1119  	store *ir.Name
  1120  	// Dynamic boolean variable marking the fact that we used this backing store.
  1121  	used *ir.Name
  1122  	// Have we used this variable statically yet? This is just a hint
  1123  	// to avoid checking the dynamic variable if the answer is obvious.
  1124  	// (usedStatic == true implies used == true)
  1125  	usedStatic bool
  1126  }
  1127  
  1128  type funcLine struct {
  1129  	f    *obj.LSym
  1130  	base *src.PosBase
  1131  	line uint
  1132  }
  1133  
  1134  type ssaLabel struct {
  1135  	target         *ssa.Block // block identified by this label
  1136  	breakTarget    *ssa.Block // block to break to in control flow node identified by this label
  1137  	continueTarget *ssa.Block // block to continue to in control flow node identified by this label
  1138  }
  1139  
  1140  // label returns the label associated with sym, creating it if necessary.
  1141  func (s *state) label(sym *types.Sym) *ssaLabel {
  1142  	lab := s.labels[sym.Name]
  1143  	if lab == nil {
  1144  		lab = new(ssaLabel)
  1145  		s.labels[sym.Name] = lab
  1146  	}
  1147  	return lab
  1148  }
  1149  
  1150  func (s *state) Logf(msg string, args ...any) { s.f.Logf(msg, args...) }
  1151  func (s *state) Log() bool                    { return s.f.Log() }
  1152  func (s *state) Fatalf(msg string, args ...any) {
  1153  	s.f.Frontend().Fatalf(s.peekPos(), msg, args...)
  1154  }
  1155  func (s *state) Warnl(pos src.XPos, msg string, args ...any) { s.f.Warnl(pos, msg, args...) }
  1156  func (s *state) Debug_checknil() bool                        { return s.f.Frontend().Debug_checknil() }
  1157  
  1158  func ssaMarker(name string) *ir.Name {
  1159  	return ir.NewNameAt(base.Pos, &types.Sym{Name: name}, nil)
  1160  }
  1161  
  1162  var (
  1163  	// marker node for the memory variable
  1164  	memVar = ssaMarker("mem")
  1165  
  1166  	// marker nodes for temporary variables
  1167  	ptrVar       = ssaMarker("ptr")
  1168  	lenVar       = ssaMarker("len")
  1169  	capVar       = ssaMarker("cap")
  1170  	typVar       = ssaMarker("typ")
  1171  	okVar        = ssaMarker("ok")
  1172  	deferBitsVar = ssaMarker("deferBits")
  1173  	hashVar      = ssaMarker("hash")
  1174  )
  1175  
  1176  // startBlock sets the current block we're generating code in to b.
  1177  func (s *state) startBlock(b *ssa.Block) {
  1178  	if s.curBlock != nil {
  1179  		s.Fatalf("starting block %v when block %v has not ended", b, s.curBlock)
  1180  	}
  1181  	s.curBlock = b
  1182  	s.vars = map[ir.Node]*ssa.Value{}
  1183  	clear(s.fwdVars)
  1184  	for len(s.blockStarts) <= int(b.ID) {
  1185  		s.blockStarts = append(s.blockStarts, src.NoXPos)
  1186  	}
  1187  }
  1188  
  1189  // endBlock marks the end of generating code for the current block.
  1190  // Returns the (former) current block. Returns nil if there is no current
  1191  // block, i.e. if no code flows to the current execution point.
  1192  func (s *state) endBlock() *ssa.Block {
  1193  	b := s.curBlock
  1194  	if b == nil {
  1195  		return nil
  1196  	}
  1197  
  1198  	s.flushPendingHeapAllocations()
  1199  
  1200  	for len(s.defvars) <= int(b.ID) {
  1201  		s.defvars = append(s.defvars, nil)
  1202  	}
  1203  	s.defvars[b.ID] = s.vars
  1204  	s.curBlock = nil
  1205  	s.vars = nil
  1206  	if b.LackingPos() {
  1207  		// Empty plain blocks get the line of their successor (handled after all blocks created),
  1208  		// except for increment blocks in For statements (handled in ssa conversion of OFOR),
  1209  		// and for blocks ending in GOTO/BREAK/CONTINUE.
  1210  		b.Pos = src.NoXPos
  1211  	} else {
  1212  		b.Pos = s.lastPos
  1213  		if s.blockStarts[b.ID] == src.NoXPos {
  1214  			s.blockStarts[b.ID] = s.lastPos
  1215  		}
  1216  	}
  1217  	return b
  1218  }
  1219  
  1220  // pushLine pushes a line number on the line number stack.
  1221  func (s *state) pushLine(line src.XPos) {
  1222  	if !line.IsKnown() {
  1223  		// the frontend may emit node with line number missing,
  1224  		// use the parent line number in this case.
  1225  		line = s.peekPos()
  1226  		if base.Flag.K != 0 {
  1227  			base.Warn("buildssa: unknown position (line 0)")
  1228  		}
  1229  	} else {
  1230  		s.lastPos = line
  1231  	}
  1232  	// The first position we see for a new block is its starting position
  1233  	// (the line number for its phis, if any).
  1234  	if b := s.curBlock; b != nil && s.blockStarts[b.ID] == src.NoXPos {
  1235  		s.blockStarts[b.ID] = line
  1236  	}
  1237  
  1238  	s.line = append(s.line, line)
  1239  }
  1240  
  1241  // popLine pops the top of the line number stack.
  1242  func (s *state) popLine() {
  1243  	s.line = s.line[:len(s.line)-1]
  1244  }
  1245  
  1246  // peekPos peeks the top of the line number stack.
  1247  func (s *state) peekPos() src.XPos {
  1248  	return s.line[len(s.line)-1]
  1249  }
  1250  
  1251  // newValue0 adds a new value with no arguments to the current block.
  1252  func (s *state) newValue0(op ssa.Op, t *types.Type) *ssa.Value {
  1253  	return s.curBlock.NewValue0(s.peekPos(), op, t)
  1254  }
  1255  
  1256  // newValue0A adds a new value with no arguments and an aux value to the current block.
  1257  func (s *state) newValue0A(op ssa.Op, t *types.Type, aux ssa.Aux) *ssa.Value {
  1258  	return s.curBlock.NewValue0A(s.peekPos(), op, t, aux)
  1259  }
  1260  
  1261  // newValue0I adds a new value with no arguments and an auxint value to the current block.
  1262  func (s *state) newValue0I(op ssa.Op, t *types.Type, auxint int64) *ssa.Value {
  1263  	return s.curBlock.NewValue0I(s.peekPos(), op, t, auxint)
  1264  }
  1265  
  1266  // newValue1 adds a new value with one argument to the current block.
  1267  func (s *state) newValue1(op ssa.Op, t *types.Type, arg *ssa.Value) *ssa.Value {
  1268  	return s.curBlock.NewValue1(s.peekPos(), op, t, arg)
  1269  }
  1270  
  1271  // newValue1A adds a new value with one argument and an aux value to the current block.
  1272  func (s *state) newValue1A(op ssa.Op, t *types.Type, aux ssa.Aux, arg *ssa.Value) *ssa.Value {
  1273  	return s.curBlock.NewValue1A(s.peekPos(), op, t, aux, arg)
  1274  }
  1275  
  1276  // newValue1Apos adds a new value with one argument and an aux value to the current block.
  1277  // isStmt determines whether the created values may be a statement or not
  1278  // (i.e., false means never, yes means maybe).
  1279  func (s *state) newValue1Apos(op ssa.Op, t *types.Type, aux ssa.Aux, arg *ssa.Value, isStmt bool) *ssa.Value {
  1280  	if isStmt {
  1281  		return s.curBlock.NewValue1A(s.peekPos(), op, t, aux, arg)
  1282  	}
  1283  	return s.curBlock.NewValue1A(s.peekPos().WithNotStmt(), op, t, aux, arg)
  1284  }
  1285  
  1286  // newValue1I adds a new value with one argument and an auxint value to the current block.
  1287  func (s *state) newValue1I(op ssa.Op, t *types.Type, aux int64, arg *ssa.Value) *ssa.Value {
  1288  	return s.curBlock.NewValue1I(s.peekPos(), op, t, aux, arg)
  1289  }
  1290  
  1291  // newValue2 adds a new value with two arguments to the current block.
  1292  func (s *state) newValue2(op ssa.Op, t *types.Type, arg0, arg1 *ssa.Value) *ssa.Value {
  1293  	return s.curBlock.NewValue2(s.peekPos(), op, t, arg0, arg1)
  1294  }
  1295  
  1296  // newValue2A adds a new value with two arguments and an aux value to the current block.
  1297  func (s *state) newValue2A(op ssa.Op, t *types.Type, aux ssa.Aux, arg0, arg1 *ssa.Value) *ssa.Value {
  1298  	return s.curBlock.NewValue2A(s.peekPos(), op, t, aux, arg0, arg1)
  1299  }
  1300  
  1301  // newValue2Apos adds a new value with two arguments and an aux value to the current block.
  1302  // isStmt determines whether the created values may be a statement or not
  1303  // (i.e., false means never, yes means maybe).
  1304  func (s *state) newValue2Apos(op ssa.Op, t *types.Type, aux ssa.Aux, arg0, arg1 *ssa.Value, isStmt bool) *ssa.Value {
  1305  	if isStmt {
  1306  		return s.curBlock.NewValue2A(s.peekPos(), op, t, aux, arg0, arg1)
  1307  	}
  1308  	return s.curBlock.NewValue2A(s.peekPos().WithNotStmt(), op, t, aux, arg0, arg1)
  1309  }
  1310  
  1311  // newValue2I adds a new value with two arguments and an auxint value to the current block.
  1312  func (s *state) newValue2I(op ssa.Op, t *types.Type, aux int64, arg0, arg1 *ssa.Value) *ssa.Value {
  1313  	return s.curBlock.NewValue2I(s.peekPos(), op, t, aux, arg0, arg1)
  1314  }
  1315  
  1316  // newValue3 adds a new value with three arguments to the current block.
  1317  func (s *state) newValue3(op ssa.Op, t *types.Type, arg0, arg1, arg2 *ssa.Value) *ssa.Value {
  1318  	return s.curBlock.NewValue3(s.peekPos(), op, t, arg0, arg1, arg2)
  1319  }
  1320  
  1321  // newValue3I adds a new value with three arguments and an auxint value to the current block.
  1322  func (s *state) newValue3I(op ssa.Op, t *types.Type, aux int64, arg0, arg1, arg2 *ssa.Value) *ssa.Value {
  1323  	return s.curBlock.NewValue3I(s.peekPos(), op, t, aux, arg0, arg1, arg2)
  1324  }
  1325  
  1326  // newValue3A adds a new value with three arguments and an aux value to the current block.
  1327  func (s *state) newValue3A(op ssa.Op, t *types.Type, aux ssa.Aux, arg0, arg1, arg2 *ssa.Value) *ssa.Value {
  1328  	return s.curBlock.NewValue3A(s.peekPos(), op, t, aux, arg0, arg1, arg2)
  1329  }
  1330  
  1331  // newValue3Apos adds a new value with three arguments and an aux value to the current block.
  1332  // isStmt determines whether the created values may be a statement or not
  1333  // (i.e., false means never, yes means maybe).
  1334  func (s *state) newValue3Apos(op ssa.Op, t *types.Type, aux ssa.Aux, arg0, arg1, arg2 *ssa.Value, isStmt bool) *ssa.Value {
  1335  	if isStmt {
  1336  		return s.curBlock.NewValue3A(s.peekPos(), op, t, aux, arg0, arg1, arg2)
  1337  	}
  1338  	return s.curBlock.NewValue3A(s.peekPos().WithNotStmt(), op, t, aux, arg0, arg1, arg2)
  1339  }
  1340  
  1341  // newValue4 adds a new value with four arguments to the current block.
  1342  func (s *state) newValue4(op ssa.Op, t *types.Type, arg0, arg1, arg2, arg3 *ssa.Value) *ssa.Value {
  1343  	return s.curBlock.NewValue4(s.peekPos(), op, t, arg0, arg1, arg2, arg3)
  1344  }
  1345  
  1346  // newValue4A adds a new value with four arguments and an aux value to the current block.
  1347  func (s *state) newValue4A(op ssa.Op, t *types.Type, aux ssa.Aux, arg0, arg1, arg2, arg3 *ssa.Value) *ssa.Value {
  1348  	return s.curBlock.NewValue4A(s.peekPos(), op, t, aux, arg0, arg1, arg2, arg3)
  1349  }
  1350  
  1351  // newValue4I adds a new value with four arguments and an auxint value to the current block.
  1352  func (s *state) newValue4I(op ssa.Op, t *types.Type, aux int64, arg0, arg1, arg2, arg3 *ssa.Value) *ssa.Value {
  1353  	return s.curBlock.NewValue4I(s.peekPos(), op, t, aux, arg0, arg1, arg2, arg3)
  1354  }
  1355  
  1356  func (s *state) entryBlock() *ssa.Block {
  1357  	b := s.f.Entry
  1358  	if base.Flag.N > 0 && s.curBlock != nil {
  1359  		// If optimizations are off, allocate in current block instead. Since with -N
  1360  		// we're not doing the CSE or tighten passes, putting lots of stuff in the
  1361  		// entry block leads to O(n^2) entries in the live value map during regalloc.
  1362  		// See issue 45897.
  1363  		b = s.curBlock
  1364  	}
  1365  	return b
  1366  }
  1367  
  1368  // entryNewValue0 adds a new value with no arguments to the entry block.
  1369  func (s *state) entryNewValue0(op ssa.Op, t *types.Type) *ssa.Value {
  1370  	return s.entryBlock().NewValue0(src.NoXPos, op, t)
  1371  }
  1372  
  1373  // entryNewValue0A adds a new value with no arguments and an aux value to the entry block.
  1374  func (s *state) entryNewValue0A(op ssa.Op, t *types.Type, aux ssa.Aux) *ssa.Value {
  1375  	return s.entryBlock().NewValue0A(src.NoXPos, op, t, aux)
  1376  }
  1377  
  1378  // entryNewValue1 adds a new value with one argument to the entry block.
  1379  func (s *state) entryNewValue1(op ssa.Op, t *types.Type, arg *ssa.Value) *ssa.Value {
  1380  	return s.entryBlock().NewValue1(src.NoXPos, op, t, arg)
  1381  }
  1382  
  1383  // entryNewValue1I adds a new value with one argument and an auxint value to the entry block.
  1384  func (s *state) entryNewValue1I(op ssa.Op, t *types.Type, auxint int64, arg *ssa.Value) *ssa.Value {
  1385  	return s.entryBlock().NewValue1I(src.NoXPos, op, t, auxint, arg)
  1386  }
  1387  
  1388  // entryNewValue1A adds a new value with one argument and an aux value to the entry block.
  1389  func (s *state) entryNewValue1A(op ssa.Op, t *types.Type, aux ssa.Aux, arg *ssa.Value) *ssa.Value {
  1390  	return s.entryBlock().NewValue1A(src.NoXPos, op, t, aux, arg)
  1391  }
  1392  
  1393  // entryNewValue2 adds a new value with two arguments to the entry block.
  1394  func (s *state) entryNewValue2(op ssa.Op, t *types.Type, arg0, arg1 *ssa.Value) *ssa.Value {
  1395  	return s.entryBlock().NewValue2(src.NoXPos, op, t, arg0, arg1)
  1396  }
  1397  
  1398  // entryNewValue2A adds a new value with two arguments and an aux value to the entry block.
  1399  func (s *state) entryNewValue2A(op ssa.Op, t *types.Type, aux ssa.Aux, arg0, arg1 *ssa.Value) *ssa.Value {
  1400  	return s.entryBlock().NewValue2A(src.NoXPos, op, t, aux, arg0, arg1)
  1401  }
  1402  
  1403  // const* routines add a new const value to the entry block.
  1404  func (s *state) constSlice(t *types.Type) *ssa.Value {
  1405  	return s.f.ConstSlice(t)
  1406  }
  1407  func (s *state) constInterface(t *types.Type) *ssa.Value {
  1408  	return s.f.ConstInterface(t)
  1409  }
  1410  func (s *state) constNil(t *types.Type) *ssa.Value { return s.f.ConstNil(t) }
  1411  func (s *state) constEmptyString(t *types.Type) *ssa.Value {
  1412  	return s.f.ConstEmptyString(t)
  1413  }
  1414  func (s *state) constBool(c bool) *ssa.Value {
  1415  	return s.f.ConstBool(types.Types[types.TBOOL], c)
  1416  }
  1417  func (s *state) constInt8(t *types.Type, c int8) *ssa.Value {
  1418  	return s.f.ConstInt8(t, c)
  1419  }
  1420  func (s *state) constInt16(t *types.Type, c int16) *ssa.Value {
  1421  	return s.f.ConstInt16(t, c)
  1422  }
  1423  func (s *state) constInt32(t *types.Type, c int32) *ssa.Value {
  1424  	return s.f.ConstInt32(t, c)
  1425  }
  1426  func (s *state) constInt64(t *types.Type, c int64) *ssa.Value {
  1427  	return s.f.ConstInt64(t, c)
  1428  }
  1429  func (s *state) constFloat32(t *types.Type, c float64) *ssa.Value {
  1430  	return s.f.ConstFloat32(t, c)
  1431  }
  1432  func (s *state) constFloat64(t *types.Type, c float64) *ssa.Value {
  1433  	return s.f.ConstFloat64(t, c)
  1434  }
  1435  func (s *state) constInt(t *types.Type, c int64) *ssa.Value {
  1436  	if s.config.PtrSize == 8 {
  1437  		return s.constInt64(t, c)
  1438  	}
  1439  	if int64(int32(c)) != c {
  1440  		s.Fatalf("integer constant too big %d", c)
  1441  	}
  1442  	return s.constInt32(t, int32(c))
  1443  }
  1444  
  1445  // newValueOrSfCall* are wrappers around newValue*, which may create a call to a
  1446  // soft-float runtime function instead (when emitting soft-float code).
  1447  func (s *state) newValueOrSfCall1(op ssa.Op, t *types.Type, arg *ssa.Value) *ssa.Value {
  1448  	if s.softFloat {
  1449  		if c, ok := s.sfcall(op, arg); ok {
  1450  			return c
  1451  		}
  1452  	}
  1453  	return s.newValue1(op, t, arg)
  1454  }
  1455  func (s *state) newValueOrSfCall2(op ssa.Op, t *types.Type, arg0, arg1 *ssa.Value) *ssa.Value {
  1456  	if s.softFloat {
  1457  		if c, ok := s.sfcall(op, arg0, arg1); ok {
  1458  			return c
  1459  		}
  1460  	}
  1461  	return s.newValue2(op, t, arg0, arg1)
  1462  }
  1463  
  1464  type instrumentKind uint8
  1465  
  1466  const (
  1467  	instrumentRead = iota
  1468  	instrumentWrite
  1469  	instrumentMove
  1470  )
  1471  
  1472  func (s *state) instrument(t *types.Type, addr *ssa.Value, kind instrumentKind) {
  1473  	s.instrument2(t, addr, nil, kind)
  1474  }
  1475  
  1476  // instrumentFields instruments a read/write operation on addr.
  1477  // If it is instrumenting for MSAN or ASAN and t is a struct type, it instruments
  1478  // operation for each field, instead of for the whole struct.
  1479  func (s *state) instrumentFields(t *types.Type, addr *ssa.Value, kind instrumentKind) {
  1480  	if !(base.Flag.MSan || base.Flag.ASan) || !isStructNotSIMD(t) {
  1481  		s.instrument(t, addr, kind)
  1482  		return
  1483  	}
  1484  	for _, f := range t.Fields() {
  1485  		if f.Sym.IsBlank() {
  1486  			continue
  1487  		}
  1488  		offptr := s.newValue1I(ssa.OpOffPtr, types.NewPtr(f.Type), f.Offset, addr)
  1489  		s.instrumentFields(f.Type, offptr, kind)
  1490  	}
  1491  }
  1492  
  1493  func (s *state) instrumentMove(t *types.Type, dst, src *ssa.Value) {
  1494  	if base.Flag.MSan {
  1495  		s.instrument2(t, dst, src, instrumentMove)
  1496  	} else {
  1497  		s.instrument(t, src, instrumentRead)
  1498  		s.instrument(t, dst, instrumentWrite)
  1499  	}
  1500  }
  1501  
  1502  func (s *state) instrument2(t *types.Type, addr, addr2 *ssa.Value, kind instrumentKind) {
  1503  	if !s.instrumentMemory {
  1504  		return
  1505  	}
  1506  
  1507  	w := t.Size()
  1508  	if w == 0 {
  1509  		return // can't race on zero-sized things
  1510  	}
  1511  
  1512  	if ssa.IsSanitizerSafeAddr(addr) {
  1513  		return
  1514  	}
  1515  
  1516  	var fn *obj.LSym
  1517  	needWidth := false
  1518  
  1519  	if addr2 != nil && kind != instrumentMove {
  1520  		panic("instrument2: non-nil addr2 for non-move instrumentation")
  1521  	}
  1522  
  1523  	if base.Flag.MSan {
  1524  		switch kind {
  1525  		case instrumentRead:
  1526  			fn = ir.Syms.Msanread
  1527  		case instrumentWrite:
  1528  			fn = ir.Syms.Msanwrite
  1529  		case instrumentMove:
  1530  			fn = ir.Syms.Msanmove
  1531  		default:
  1532  			panic("unreachable")
  1533  		}
  1534  		needWidth = true
  1535  	} else if base.Flag.Race && t.NumComponents(types.CountBlankFields) > 1 {
  1536  		// for composite objects we have to write every address
  1537  		// because a write might happen to any subobject.
  1538  		// composites with only one element don't have subobjects, though.
  1539  		switch kind {
  1540  		case instrumentRead:
  1541  			fn = ir.Syms.Racereadrange
  1542  		case instrumentWrite:
  1543  			fn = ir.Syms.Racewriterange
  1544  		default:
  1545  			panic("unreachable")
  1546  		}
  1547  		needWidth = true
  1548  	} else if base.Flag.Race {
  1549  		// for non-composite objects we can write just the start
  1550  		// address, as any write must write the first byte.
  1551  		switch kind {
  1552  		case instrumentRead:
  1553  			fn = ir.Syms.Raceread
  1554  		case instrumentWrite:
  1555  			fn = ir.Syms.Racewrite
  1556  		default:
  1557  			panic("unreachable")
  1558  		}
  1559  	} else if base.Flag.ASan {
  1560  		switch kind {
  1561  		case instrumentRead:
  1562  			fn = ir.Syms.Asanread
  1563  		case instrumentWrite:
  1564  			fn = ir.Syms.Asanwrite
  1565  		default:
  1566  			panic("unreachable")
  1567  		}
  1568  		needWidth = true
  1569  	} else {
  1570  		panic("unreachable")
  1571  	}
  1572  
  1573  	args := []*ssa.Value{addr}
  1574  	if addr2 != nil {
  1575  		args = append(args, addr2)
  1576  	}
  1577  	if needWidth {
  1578  		args = append(args, s.constInt(types.Types[types.TUINTPTR], w))
  1579  	}
  1580  	s.rtcall(fn, true, nil, args...)
  1581  }
  1582  
  1583  func (s *state) load(t *types.Type, src *ssa.Value) *ssa.Value {
  1584  	s.instrumentFields(t, src, instrumentRead)
  1585  	return s.rawLoad(t, src)
  1586  }
  1587  
  1588  func (s *state) rawLoad(t *types.Type, src *ssa.Value) *ssa.Value {
  1589  	return s.newValue2(ssa.OpLoad, t, src, s.mem())
  1590  }
  1591  
  1592  func (s *state) store(t *types.Type, dst, val *ssa.Value) {
  1593  	s.vars[memVar] = s.newValue3A(ssa.OpStore, types.TypeMem, t, dst, val, s.mem())
  1594  }
  1595  
  1596  func (s *state) zero(t *types.Type, dst *ssa.Value) {
  1597  	s.instrument(t, dst, instrumentWrite)
  1598  	store := s.newValue2I(ssa.OpZero, types.TypeMem, t.Size(), dst, s.mem())
  1599  	store.Aux = t
  1600  	s.vars[memVar] = store
  1601  }
  1602  
  1603  func (s *state) move(t *types.Type, dst, src *ssa.Value) {
  1604  	s.moveWhichMayOverlap(t, dst, src, false)
  1605  }
  1606  func (s *state) moveWhichMayOverlap(t *types.Type, dst, src *ssa.Value, mayOverlap bool) {
  1607  	s.instrumentMove(t, dst, src)
  1608  	if mayOverlap && t.IsArray() && t.NumElem() > 1 && !ssa.IsInlinableMemmove(dst, src, t.Size(), s.f.Config) {
  1609  		// Normally, when moving Go values of type T from one location to another,
  1610  		// we don't need to worry about partial overlaps. The two Ts must either be
  1611  		// in disjoint (nonoverlapping) memory or in exactly the same location.
  1612  		// There are 2 cases where this isn't true:
  1613  		//  1) Using unsafe you can arrange partial overlaps.
  1614  		//  2) Since Go 1.17, you can use a cast from a slice to a ptr-to-array.
  1615  		//     https://go.dev/ref/spec#Conversions_from_slice_to_array_pointer
  1616  		//     This feature can be used to construct partial overlaps of array types.
  1617  		//       var a [3]int
  1618  		//       p := (*[2]int)(a[:])
  1619  		//       q := (*[2]int)(a[1:])
  1620  		//       *p = *q
  1621  		// We don't care about solving 1. Or at least, we haven't historically
  1622  		// and no one has complained.
  1623  		// For 2, we need to ensure that if there might be partial overlap,
  1624  		// then we can't use OpMove; we must use memmove instead.
  1625  		// (memmove handles partial overlap by copying in the correct
  1626  		// direction. OpMove does not.)
  1627  		//
  1628  		// Note that we have to be careful here not to introduce a call when
  1629  		// we're marshaling arguments to a call or unmarshaling results from a call.
  1630  		// Cases where this is happening must pass mayOverlap to false.
  1631  		// (Currently this only happens when unmarshaling results of a call.)
  1632  		if t.HasPointers() {
  1633  			s.rtcall(ir.Syms.Typedmemmove, true, nil, s.reflectType(t), dst, src)
  1634  			// We would have otherwise implemented this move with straightline code,
  1635  			// including a write barrier. Pretend we issue a write barrier here,
  1636  			// so that the write barrier tests work. (Otherwise they'd need to know
  1637  			// the details of IsInlineableMemmove.)
  1638  			s.curfn.SetWBPos(s.peekPos())
  1639  		} else {
  1640  			s.rtcall(ir.Syms.Memmove, true, nil, dst, src, s.constInt(types.Types[types.TUINTPTR], t.Size()))
  1641  		}
  1642  		ssa.LogLargeCopy(s.f.Name, s.peekPos(), t.Size())
  1643  		return
  1644  	}
  1645  	store := s.newValue3I(ssa.OpMove, types.TypeMem, t.Size(), dst, src, s.mem())
  1646  	store.Aux = t
  1647  	s.vars[memVar] = store
  1648  }
  1649  
  1650  // stmtList converts the statement list n to SSA and adds it to s.
  1651  func (s *state) stmtList(l ir.Nodes) {
  1652  	for _, n := range l {
  1653  		s.stmt(n)
  1654  	}
  1655  }
  1656  
  1657  func peelConvNop(n ir.Node) ir.Node {
  1658  	if n == nil {
  1659  		return n
  1660  	}
  1661  	for n.Op() == ir.OCONVNOP {
  1662  		n = n.(*ir.ConvExpr).X
  1663  	}
  1664  	return n
  1665  }
  1666  
  1667  // stmt converts the statement n to SSA and adds it to s.
  1668  func (s *state) stmt(n ir.Node) {
  1669  	s.pushLine(n.Pos())
  1670  	defer s.popLine()
  1671  
  1672  	// If s.curBlock is nil, and n isn't a label (which might have an associated goto somewhere),
  1673  	// then this code is dead. Stop here.
  1674  	if s.curBlock == nil && n.Op() != ir.OLABEL {
  1675  		return
  1676  	}
  1677  
  1678  	s.stmtList(n.Init())
  1679  	switch n.Op() {
  1680  
  1681  	case ir.OBLOCK:
  1682  		n := n.(*ir.BlockStmt)
  1683  		s.stmtList(n.List)
  1684  
  1685  	case ir.OFALL: // no-op
  1686  
  1687  	// Expression statements
  1688  	case ir.OCALLFUNC:
  1689  		n := n.(*ir.CallExpr)
  1690  		if ir.IsIntrinsicCall(n) {
  1691  			s.intrinsicCall(n)
  1692  			return
  1693  		}
  1694  		fallthrough
  1695  
  1696  	case ir.OCALLINTER:
  1697  		n := n.(*ir.CallExpr)
  1698  		s.callResult(n, callNormal)
  1699  		if n.Op() == ir.OCALLFUNC && n.Fun.Op() == ir.ONAME && n.Fun.(*ir.Name).Class == ir.PFUNC {
  1700  			if fn := n.Fun.Sym().Name; base.Flag.CompilingRuntime && fn == "throw" ||
  1701  				n.Fun.Sym().Pkg == ir.Pkgs.Runtime &&
  1702  					(fn == "throwinit" || fn == "gopanic" || fn == "panicwrap" || fn == "block" ||
  1703  						fn == "panicmakeslicelen" || fn == "panicmakeslicecap" || fn == "panicunsafeslicelen" ||
  1704  						fn == "panicunsafeslicenilptr" || fn == "panicunsafestringlen" || fn == "panicunsafestringnilptr" ||
  1705  						fn == "panicrangestate") {
  1706  				m := s.mem()
  1707  				b := s.endBlock()
  1708  				b.Kind = ssa.BlockExit
  1709  				b.SetControl(m)
  1710  				// TODO: never rewrite OPANIC to OCALLFUNC in the
  1711  				// first place. Need to wait until all backends
  1712  				// go through SSA.
  1713  			}
  1714  		}
  1715  	case ir.ODEFER:
  1716  		n := n.(*ir.GoDeferStmt)
  1717  		if base.Debug.Defer > 0 {
  1718  			var defertype string
  1719  			if s.hasOpenDefers {
  1720  				defertype = "open-coded"
  1721  			} else if n.Esc() == ir.EscNever {
  1722  				defertype = "stack-allocated"
  1723  			} else {
  1724  				defertype = "heap-allocated"
  1725  			}
  1726  			base.WarnfAt(n.Pos(), "%s defer", defertype)
  1727  		}
  1728  		if s.hasOpenDefers {
  1729  			s.openDeferRecord(n.Call.(*ir.CallExpr))
  1730  		} else {
  1731  			d := callDefer
  1732  			if n.Esc() == ir.EscNever && n.DeferAt == nil {
  1733  				d = callDeferStack
  1734  			}
  1735  			s.call(n.Call.(*ir.CallExpr), d, false, n.DeferAt)
  1736  		}
  1737  	case ir.OGO:
  1738  		n := n.(*ir.GoDeferStmt)
  1739  		s.callResult(n.Call.(*ir.CallExpr), callGo)
  1740  
  1741  	case ir.OAS2DOTTYPE:
  1742  		n := n.(*ir.AssignListStmt)
  1743  		var res, resok *ssa.Value
  1744  		if n.Rhs[0].Op() == ir.ODOTTYPE2 {
  1745  			res, resok = s.dottype(n.Rhs[0].(*ir.TypeAssertExpr), true)
  1746  		} else {
  1747  			res, resok = s.dynamicDottype(n.Rhs[0].(*ir.DynamicTypeAssertExpr), true)
  1748  		}
  1749  		deref := false
  1750  		if !ssa.CanSSA(n.Rhs[0].Type()) {
  1751  			if res.Op != ssa.OpLoad {
  1752  				s.Fatalf("dottype of non-load")
  1753  			}
  1754  			mem := s.mem()
  1755  			if res.Args[1] != mem {
  1756  				s.Fatalf("memory no longer live from 2-result dottype load")
  1757  			}
  1758  			deref = true
  1759  			res = res.Args[0]
  1760  		}
  1761  		s.assign(n.Lhs[0], res, deref, 0)
  1762  		s.assign(n.Lhs[1], resok, false, 0)
  1763  		return
  1764  
  1765  	case ir.OAS2FUNC:
  1766  		// We come here only when it is an intrinsic call returning two values.
  1767  		n := n.(*ir.AssignListStmt)
  1768  		call := n.Rhs[0].(*ir.CallExpr)
  1769  		if !ir.IsIntrinsicCall(call) {
  1770  			s.Fatalf("non-intrinsic AS2FUNC not expanded %v", call)
  1771  		}
  1772  		v := s.intrinsicCall(call)
  1773  		v1 := s.newValue1(ssa.OpSelect0, n.Lhs[0].Type(), v)
  1774  		v2 := s.newValue1(ssa.OpSelect1, n.Lhs[1].Type(), v)
  1775  		s.assign(n.Lhs[0], v1, false, 0)
  1776  		s.assign(n.Lhs[1], v2, false, 0)
  1777  		return
  1778  
  1779  	case ir.ODCL:
  1780  		n := n.(*ir.Decl)
  1781  		if v := n.X; v.Esc() == ir.EscHeap {
  1782  			s.newHeapaddr(v)
  1783  		}
  1784  
  1785  	case ir.OLABEL:
  1786  		n := n.(*ir.LabelStmt)
  1787  		sym := n.Label
  1788  		if sym.IsBlank() {
  1789  			// Nothing to do because the label isn't targetable. See issue 52278.
  1790  			break
  1791  		}
  1792  		lab := s.label(sym)
  1793  
  1794  		// The label might already have a target block via a goto.
  1795  		if lab.target == nil {
  1796  			lab.target = s.f.NewBlock(ssa.BlockPlain)
  1797  		}
  1798  
  1799  		// Go to that label.
  1800  		// (We pretend "label:" is preceded by "goto label", unless the predecessor is unreachable.)
  1801  		if s.curBlock != nil {
  1802  			b := s.endBlock()
  1803  			b.AddEdgeTo(lab.target)
  1804  		}
  1805  		s.startBlock(lab.target)
  1806  
  1807  	case ir.OGOTO:
  1808  		n := n.(*ir.BranchStmt)
  1809  		sym := n.Label
  1810  
  1811  		lab := s.label(sym)
  1812  		if lab.target == nil {
  1813  			lab.target = s.f.NewBlock(ssa.BlockPlain)
  1814  		}
  1815  
  1816  		b := s.endBlock()
  1817  		b.Pos = s.lastPos.WithIsStmt() // Do this even if b is an empty block.
  1818  		b.AddEdgeTo(lab.target)
  1819  
  1820  	case ir.OAS:
  1821  		n := n.(*ir.AssignStmt)
  1822  		if n.X == n.Y && n.X.Op() == ir.ONAME {
  1823  			// An x=x assignment. No point in doing anything
  1824  			// here. In addition, skipping this assignment
  1825  			// prevents generating:
  1826  			//   VARDEF x
  1827  			//   COPY x -> x
  1828  			// which is bad because x is incorrectly considered
  1829  			// dead before the vardef. See issue #14904.
  1830  			return
  1831  		}
  1832  
  1833  		// mayOverlap keeps track of whether the LHS and RHS might
  1834  		// refer to partially overlapping memory. Partial overlapping can
  1835  		// only happen for arrays, see the comment in moveWhichMayOverlap.
  1836  		//
  1837  		// If both sides of the assignment are not dereferences, then partial
  1838  		// overlap can't happen. Partial overlap can only occur only when the
  1839  		// arrays referenced are strictly smaller parts of the same base array.
  1840  		// If one side of the assignment is a full array, then partial overlap
  1841  		// can't happen. (The arrays are either disjoint or identical.)
  1842  		ny := peelConvNop(n.Y)
  1843  		mayOverlap := n.X.Op() == ir.ODEREF && (n.Y != nil && ny.Op() == ir.ODEREF)
  1844  		if ny != nil && ny.Op() == ir.ODEREF {
  1845  			p := peelConvNop(ny.(*ir.StarExpr).X)
  1846  			if p.Op() == ir.OSPTR && p.(*ir.UnaryExpr).X.Type().IsString() {
  1847  				// Pointer fields of strings point to unmodifiable memory.
  1848  				// That memory can't overlap with the memory being written.
  1849  				mayOverlap = false
  1850  			}
  1851  		}
  1852  
  1853  		// Evaluate RHS.
  1854  		rhs := n.Y
  1855  		if rhs != nil {
  1856  			switch rhs.Op() {
  1857  			case ir.OSTRUCTLIT, ir.OARRAYLIT, ir.OSLICELIT:
  1858  				// All literals with nonzero fields have already been
  1859  				// rewritten during walk. Any that remain are just T{}
  1860  				// or equivalents. Use the zero value.
  1861  				if !ir.IsZero(rhs) {
  1862  					s.Fatalf("literal with nonzero value in SSA: %v", rhs)
  1863  				}
  1864  				rhs = nil
  1865  			case ir.OAPPEND:
  1866  				rhs := rhs.(*ir.CallExpr)
  1867  				// Check whether we're writing the result of an append back to the same slice.
  1868  				// If so, we handle it specially to avoid write barriers on the fast
  1869  				// (non-growth) path.
  1870  				if !ir.SameSafeExpr(n.X, rhs.Args[0]) || base.Flag.N != 0 {
  1871  					break
  1872  				}
  1873  				// If the slice can be SSA'd, it'll be on the stack,
  1874  				// so there will be no write barriers,
  1875  				// so there's no need to attempt to prevent them.
  1876  				if s.canSSA(n.X) {
  1877  					if base.Debug.Append > 0 { // replicating old diagnostic message
  1878  						base.WarnfAt(n.Pos(), "append: len-only update (in local slice)")
  1879  					}
  1880  					break
  1881  				}
  1882  				if base.Debug.Append > 0 {
  1883  					base.WarnfAt(n.Pos(), "append: len-only update")
  1884  				}
  1885  				s.append(rhs, true)
  1886  				return
  1887  			}
  1888  		}
  1889  
  1890  		if ir.IsBlank(n.X) {
  1891  			// _ = rhs
  1892  			// Just evaluate rhs for side-effects.
  1893  			if rhs != nil {
  1894  				s.expr(rhs)
  1895  			}
  1896  			return
  1897  		}
  1898  
  1899  		var t *types.Type
  1900  		if n.Y != nil {
  1901  			t = n.Y.Type()
  1902  		} else {
  1903  			t = n.X.Type()
  1904  		}
  1905  
  1906  		var r *ssa.Value
  1907  		deref := !ssa.CanSSA(t)
  1908  		if deref {
  1909  			if rhs == nil {
  1910  				r = nil // Signal assign to use OpZero.
  1911  			} else {
  1912  				r = s.addr(rhs)
  1913  			}
  1914  		} else {
  1915  			if rhs == nil {
  1916  				r = s.zeroVal(t)
  1917  			} else {
  1918  				r = s.expr(rhs)
  1919  			}
  1920  		}
  1921  
  1922  		var skip skipMask
  1923  		if rhs != nil && (rhs.Op() == ir.OSLICE || rhs.Op() == ir.OSLICE3 || rhs.Op() == ir.OSLICESTR) && ir.SameSafeExpr(rhs.(*ir.SliceExpr).X, n.X) {
  1924  			// We're assigning a slicing operation back to its source.
  1925  			// Don't write back fields we aren't changing. See issue #14855.
  1926  			rhs := rhs.(*ir.SliceExpr)
  1927  			i, j, k := rhs.Low, rhs.High, rhs.Max
  1928  			if i != nil && (i.Op() == ir.OLITERAL && i.Val().Kind() == constant.Int && ir.Int64Val(i) == 0) {
  1929  				// [0:...] is the same as [:...]
  1930  				i = nil
  1931  			}
  1932  			// TODO: detect defaults for len/cap also.
  1933  			// Currently doesn't really work because (*p)[:len(*p)] appears here as:
  1934  			//    tmp = len(*p)
  1935  			//    (*p)[:tmp]
  1936  			// if j != nil && (j.Op == OLEN && SameSafeExpr(j.Left, n.Left)) {
  1937  			//      j = nil
  1938  			// }
  1939  			// if k != nil && (k.Op == OCAP && SameSafeExpr(k.Left, n.Left)) {
  1940  			//      k = nil
  1941  			// }
  1942  			if i == nil {
  1943  				skip |= skipPtr
  1944  				if j == nil {
  1945  					skip |= skipLen
  1946  				}
  1947  				if k == nil {
  1948  					skip |= skipCap
  1949  				}
  1950  			}
  1951  		}
  1952  
  1953  		s.assignWhichMayOverlap(n.X, r, deref, skip, mayOverlap)
  1954  
  1955  	case ir.OIF:
  1956  		n := n.(*ir.IfStmt)
  1957  		if ir.IsConst(n.Cond, constant.Bool) {
  1958  			s.stmtList(n.Cond.Init())
  1959  			if ir.BoolVal(n.Cond) {
  1960  				s.stmtList(n.Body)
  1961  			} else {
  1962  				s.stmtList(n.Else)
  1963  			}
  1964  			break
  1965  		}
  1966  
  1967  		bEnd := s.f.NewBlock(ssa.BlockPlain)
  1968  		var likely int8
  1969  		if n.Likely {
  1970  			likely = 1
  1971  		}
  1972  		var bThen *ssa.Block
  1973  		if len(n.Body) != 0 {
  1974  			bThen = s.f.NewBlock(ssa.BlockPlain)
  1975  		} else {
  1976  			bThen = bEnd
  1977  		}
  1978  		var bElse *ssa.Block
  1979  		if len(n.Else) != 0 {
  1980  			bElse = s.f.NewBlock(ssa.BlockPlain)
  1981  		} else {
  1982  			bElse = bEnd
  1983  		}
  1984  		s.condBranch(n.Cond, bThen, bElse, likely)
  1985  
  1986  		if len(n.Body) != 0 {
  1987  			s.startBlock(bThen)
  1988  			s.stmtList(n.Body)
  1989  			if b := s.endBlock(); b != nil {
  1990  				b.AddEdgeTo(bEnd)
  1991  			}
  1992  		}
  1993  		if len(n.Else) != 0 {
  1994  			s.startBlock(bElse)
  1995  			s.stmtList(n.Else)
  1996  			if b := s.endBlock(); b != nil {
  1997  				b.AddEdgeTo(bEnd)
  1998  			}
  1999  		}
  2000  		s.startBlock(bEnd)
  2001  
  2002  	case ir.ORETURN:
  2003  		n := n.(*ir.ReturnStmt)
  2004  		s.stmtList(n.Results)
  2005  		b := s.exit()
  2006  		b.Pos = s.lastPos.WithIsStmt()
  2007  
  2008  	case ir.OTAILCALL:
  2009  		n := n.(*ir.TailCallStmt)
  2010  		s.callResult(n.Call, callTail)
  2011  		call := s.mem()
  2012  		b := s.endBlock()
  2013  		b.Kind = ssa.BlockRetJmp // could use BlockExit. BlockRetJmp is mostly for clarity.
  2014  		b.SetControl(call)
  2015  
  2016  	case ir.OCONTINUE, ir.OBREAK:
  2017  		n := n.(*ir.BranchStmt)
  2018  		var to *ssa.Block
  2019  		if n.Label == nil {
  2020  			// plain break/continue
  2021  			switch n.Op() {
  2022  			case ir.OCONTINUE:
  2023  				to = s.continueTo
  2024  			case ir.OBREAK:
  2025  				to = s.breakTo
  2026  			}
  2027  		} else {
  2028  			// labeled break/continue; look up the target
  2029  			sym := n.Label
  2030  			lab := s.label(sym)
  2031  			switch n.Op() {
  2032  			case ir.OCONTINUE:
  2033  				to = lab.continueTarget
  2034  			case ir.OBREAK:
  2035  				to = lab.breakTarget
  2036  			}
  2037  		}
  2038  
  2039  		b := s.endBlock()
  2040  		b.Pos = s.lastPos.WithIsStmt() // Do this even if b is an empty block.
  2041  		b.AddEdgeTo(to)
  2042  
  2043  	case ir.OFOR:
  2044  		// OFOR: for Ninit; Left; Right { Nbody }
  2045  		// cond (Left); body (Nbody); incr (Right)
  2046  		n := n.(*ir.ForStmt)
  2047  		base.Assert(!n.DistinctVars) // Should all be rewritten before escape analysis
  2048  		bCond := s.f.NewBlock(ssa.BlockPlain)
  2049  		bBody := s.f.NewBlock(ssa.BlockPlain)
  2050  		bIncr := s.f.NewBlock(ssa.BlockPlain)
  2051  		bEnd := s.f.NewBlock(ssa.BlockPlain)
  2052  
  2053  		// ensure empty for loops have correct position; issue #30167
  2054  		bBody.Pos = n.Pos()
  2055  
  2056  		// first, jump to condition test
  2057  		b := s.endBlock()
  2058  		b.AddEdgeTo(bCond)
  2059  
  2060  		// generate code to test condition
  2061  		s.startBlock(bCond)
  2062  		if n.Cond != nil {
  2063  			s.condBranch(n.Cond, bBody, bEnd, 1)
  2064  		} else {
  2065  			b := s.endBlock()
  2066  			b.Kind = ssa.BlockPlain
  2067  			b.AddEdgeTo(bBody)
  2068  		}
  2069  
  2070  		// set up for continue/break in body
  2071  		prevContinue := s.continueTo
  2072  		prevBreak := s.breakTo
  2073  		s.continueTo = bIncr
  2074  		s.breakTo = bEnd
  2075  		var lab *ssaLabel
  2076  		if sym := n.Label; sym != nil {
  2077  			// labeled for loop
  2078  			lab = s.label(sym)
  2079  			lab.continueTarget = bIncr
  2080  			lab.breakTarget = bEnd
  2081  		}
  2082  
  2083  		// generate body
  2084  		s.startBlock(bBody)
  2085  		s.stmtList(n.Body)
  2086  
  2087  		// tear down continue/break
  2088  		s.continueTo = prevContinue
  2089  		s.breakTo = prevBreak
  2090  		if lab != nil {
  2091  			lab.continueTarget = nil
  2092  			lab.breakTarget = nil
  2093  		}
  2094  
  2095  		// done with body, goto incr
  2096  		if b := s.endBlock(); b != nil {
  2097  			b.AddEdgeTo(bIncr)
  2098  		}
  2099  
  2100  		// generate incr
  2101  		s.startBlock(bIncr)
  2102  		if n.Post != nil {
  2103  			s.stmt(n.Post)
  2104  		}
  2105  		if b := s.endBlock(); b != nil {
  2106  			b.AddEdgeTo(bCond)
  2107  			// It can happen that bIncr ends in a block containing only VARKILL,
  2108  			// and that muddles the debugging experience.
  2109  			if b.Pos == src.NoXPos {
  2110  				b.Pos = bCond.Pos
  2111  			}
  2112  		}
  2113  
  2114  		s.startBlock(bEnd)
  2115  
  2116  	case ir.OSWITCH, ir.OSELECT:
  2117  		// These have been mostly rewritten by the front end into their Nbody fields.
  2118  		// Our main task is to correctly hook up any break statements.
  2119  		bEnd := s.f.NewBlock(ssa.BlockPlain)
  2120  
  2121  		prevBreak := s.breakTo
  2122  		s.breakTo = bEnd
  2123  		var sym *types.Sym
  2124  		var body ir.Nodes
  2125  		if n.Op() == ir.OSWITCH {
  2126  			n := n.(*ir.SwitchStmt)
  2127  			sym = n.Label
  2128  			body = n.Compiled
  2129  		} else {
  2130  			n := n.(*ir.SelectStmt)
  2131  			sym = n.Label
  2132  			body = n.Compiled
  2133  		}
  2134  
  2135  		var lab *ssaLabel
  2136  		if sym != nil {
  2137  			// labeled
  2138  			lab = s.label(sym)
  2139  			lab.breakTarget = bEnd
  2140  		}
  2141  
  2142  		// generate body code
  2143  		s.stmtList(body)
  2144  
  2145  		s.breakTo = prevBreak
  2146  		if lab != nil {
  2147  			lab.breakTarget = nil
  2148  		}
  2149  
  2150  		// walk adds explicit OBREAK nodes to the end of all reachable code paths.
  2151  		// If we still have a current block here, then mark it unreachable.
  2152  		if s.curBlock != nil {
  2153  			m := s.mem()
  2154  			b := s.endBlock()
  2155  			b.Kind = ssa.BlockExit
  2156  			b.SetControl(m)
  2157  		}
  2158  		s.startBlock(bEnd)
  2159  
  2160  	case ir.OJUMPTABLE:
  2161  		n := n.(*ir.JumpTableStmt)
  2162  
  2163  		// Make blocks we'll need.
  2164  		jt := s.f.NewBlock(ssa.BlockJumpTable)
  2165  		bEnd := s.f.NewBlock(ssa.BlockPlain)
  2166  
  2167  		// The only thing that needs evaluating is the index we're looking up.
  2168  		idx := s.expr(n.Idx)
  2169  		unsigned := idx.Type.IsUnsigned()
  2170  
  2171  		// Extend so we can do everything in uintptr arithmetic.
  2172  		t := types.Types[types.TUINTPTR]
  2173  		idx = s.conv(nil, idx, idx.Type, t)
  2174  
  2175  		// The ending condition for the current block decides whether we'll use
  2176  		// the jump table at all.
  2177  		// We check that min <= idx <= max and jump around the jump table
  2178  		// if that test fails.
  2179  		// We implement min <= idx <= max with 0 <= idx-min <= max-min, because
  2180  		// we'll need idx-min anyway as the control value for the jump table.
  2181  		var min, max uint64
  2182  		if unsigned {
  2183  			min, _ = constant.Uint64Val(n.Cases[0])
  2184  			max, _ = constant.Uint64Val(n.Cases[len(n.Cases)-1])
  2185  		} else {
  2186  			mn, _ := constant.Int64Val(n.Cases[0])
  2187  			mx, _ := constant.Int64Val(n.Cases[len(n.Cases)-1])
  2188  			min = uint64(mn)
  2189  			max = uint64(mx)
  2190  		}
  2191  		// Compare idx-min with max-min, to see if we can use the jump table.
  2192  		idx = s.newValue2(s.ssaOp(ir.OSUB, t), t, idx, s.uintptrConstant(min))
  2193  		width := s.uintptrConstant(max - min)
  2194  		cmp := s.newValue2(s.ssaOp(ir.OLE, t), types.Types[types.TBOOL], idx, width)
  2195  		b := s.endBlock()
  2196  		b.Kind = ssa.BlockIf
  2197  		b.SetControl(cmp)
  2198  		b.AddEdgeTo(jt)             // in range - use jump table
  2199  		b.AddEdgeTo(bEnd)           // out of range - no case in the jump table will trigger
  2200  		b.Likely = ssa.BranchLikely // TODO: assumes missing the table entirely is unlikely. True?
  2201  
  2202  		// Build jump table block.
  2203  		s.startBlock(jt)
  2204  		jt.Pos = n.Pos()
  2205  		if base.Flag.Cfg.SpectreIndex {
  2206  			idx = s.newValue2(ssa.OpSpectreSliceIndex, t, idx, width)
  2207  		}
  2208  		jt.SetControl(idx)
  2209  
  2210  		// Figure out where we should go for each index in the table.
  2211  		table := make([]*ssa.Block, max-min+1)
  2212  		for i := range table {
  2213  			table[i] = bEnd // default target
  2214  		}
  2215  		for i := range n.Targets {
  2216  			c := n.Cases[i]
  2217  			lab := s.label(n.Targets[i])
  2218  			if lab.target == nil {
  2219  				lab.target = s.f.NewBlock(ssa.BlockPlain)
  2220  			}
  2221  			var val uint64
  2222  			if unsigned {
  2223  				val, _ = constant.Uint64Val(c)
  2224  			} else {
  2225  				vl, _ := constant.Int64Val(c)
  2226  				val = uint64(vl)
  2227  			}
  2228  			// Overwrite the default target.
  2229  			table[val-min] = lab.target
  2230  		}
  2231  		for _, t := range table {
  2232  			jt.AddEdgeTo(t)
  2233  		}
  2234  		s.endBlock()
  2235  
  2236  		s.startBlock(bEnd)
  2237  
  2238  	case ir.OINTERFACESWITCH:
  2239  		n := n.(*ir.InterfaceSwitchStmt)
  2240  		typs := s.f.Config.Types
  2241  
  2242  		t := s.expr(n.RuntimeType)
  2243  		h := s.expr(n.Hash)
  2244  		d := s.newValue1A(ssa.OpAddr, typs.BytePtr, n.Descriptor, s.sb)
  2245  
  2246  		// Check the cache first.
  2247  		var merge *ssa.Block
  2248  		if base.Flag.N == 0 && rtabi.UseInterfaceSwitchCache(Arch.LinkArch.Family) {
  2249  			// Note: we can only use the cache if we have the right atomic load instruction.
  2250  			// Double-check that here.
  2251  			if intrinsics.lookup(Arch.LinkArch.Arch, "internal/runtime/atomic", "Loadp") == nil {
  2252  				s.Fatalf("atomic load not available")
  2253  			}
  2254  			merge = s.f.NewBlock(ssa.BlockPlain)
  2255  			cacheHit := s.f.NewBlock(ssa.BlockPlain)
  2256  			cacheMiss := s.f.NewBlock(ssa.BlockPlain)
  2257  			loopHead := s.f.NewBlock(ssa.BlockPlain)
  2258  			loopBody := s.f.NewBlock(ssa.BlockPlain)
  2259  
  2260  			// Pick right size ops.
  2261  			var mul, and, add, zext ssa.Op
  2262  			if s.config.PtrSize == 4 {
  2263  				mul = ssa.OpMul32
  2264  				and = ssa.OpAnd32
  2265  				add = ssa.OpAdd32
  2266  				zext = ssa.OpCopy
  2267  			} else {
  2268  				mul = ssa.OpMul64
  2269  				and = ssa.OpAnd64
  2270  				add = ssa.OpAdd64
  2271  				zext = ssa.OpZeroExt32to64
  2272  			}
  2273  
  2274  			// Load cache pointer out of descriptor, with an atomic load so
  2275  			// we ensure that we see a fully written cache.
  2276  			atomicLoad := s.newValue2(ssa.OpAtomicLoadPtr, types.NewTuple(typs.BytePtr, types.TypeMem), d, s.mem())
  2277  			cache := s.newValue1(ssa.OpSelect0, typs.BytePtr, atomicLoad)
  2278  			s.vars[memVar] = s.newValue1(ssa.OpSelect1, types.TypeMem, atomicLoad)
  2279  
  2280  			// Initialize hash variable.
  2281  			s.vars[hashVar] = s.newValue1(zext, typs.Uintptr, h)
  2282  
  2283  			// Load mask from cache.
  2284  			mask := s.newValue2(ssa.OpLoad, typs.Uintptr, cache, s.mem())
  2285  			// Jump to loop head.
  2286  			b := s.endBlock()
  2287  			b.AddEdgeTo(loopHead)
  2288  
  2289  			// At loop head, get pointer to the cache entry.
  2290  			//   e := &cache.Entries[hash&mask]
  2291  			s.startBlock(loopHead)
  2292  			entries := s.newValue2(ssa.OpAddPtr, typs.UintptrPtr, cache, s.uintptrConstant(uint64(s.config.PtrSize)))
  2293  			idx := s.newValue2(and, typs.Uintptr, s.variable(hashVar, typs.Uintptr), mask)
  2294  			idx = s.newValue2(mul, typs.Uintptr, idx, s.uintptrConstant(uint64(3*s.config.PtrSize)))
  2295  			e := s.newValue2(ssa.OpAddPtr, typs.UintptrPtr, entries, idx)
  2296  			//   hash++
  2297  			s.vars[hashVar] = s.newValue2(add, typs.Uintptr, s.variable(hashVar, typs.Uintptr), s.uintptrConstant(1))
  2298  
  2299  			// Look for a cache hit.
  2300  			//   if e.Typ == t { goto hit }
  2301  			eTyp := s.newValue2(ssa.OpLoad, typs.Uintptr, e, s.mem())
  2302  			cmp1 := s.newValue2(ssa.OpEqPtr, typs.Bool, t, eTyp)
  2303  			b = s.endBlock()
  2304  			b.Kind = ssa.BlockIf
  2305  			b.SetControl(cmp1)
  2306  			b.AddEdgeTo(cacheHit)
  2307  			b.AddEdgeTo(loopBody)
  2308  
  2309  			// Look for an empty entry, the tombstone for this hash table.
  2310  			//   if e.Typ == nil { goto miss }
  2311  			s.startBlock(loopBody)
  2312  			cmp2 := s.newValue2(ssa.OpEqPtr, typs.Bool, eTyp, s.constNil(typs.BytePtr))
  2313  			b = s.endBlock()
  2314  			b.Kind = ssa.BlockIf
  2315  			b.SetControl(cmp2)
  2316  			b.AddEdgeTo(cacheMiss)
  2317  			b.AddEdgeTo(loopHead)
  2318  
  2319  			// On a hit, load the data fields of the cache entry.
  2320  			//   Case = e.Case
  2321  			//   Itab = e.Itab
  2322  			s.startBlock(cacheHit)
  2323  			eCase := s.newValue2(ssa.OpLoad, typs.Int, s.newValue1I(ssa.OpOffPtr, typs.IntPtr, s.config.PtrSize, e), s.mem())
  2324  			eItab := s.newValue2(ssa.OpLoad, typs.BytePtr, s.newValue1I(ssa.OpOffPtr, typs.BytePtrPtr, 2*s.config.PtrSize, e), s.mem())
  2325  			s.assign(n.Case, eCase, false, 0)
  2326  			s.assign(n.Itab, eItab, false, 0)
  2327  			b = s.endBlock()
  2328  			b.AddEdgeTo(merge)
  2329  
  2330  			// On a miss, call into the runtime to get the answer.
  2331  			s.startBlock(cacheMiss)
  2332  		}
  2333  
  2334  		r := s.rtcall(ir.Syms.InterfaceSwitch, true, []*types.Type{typs.Int, typs.BytePtr}, d, t)
  2335  		s.assign(n.Case, r[0], false, 0)
  2336  		s.assign(n.Itab, r[1], false, 0)
  2337  
  2338  		if merge != nil {
  2339  			// Cache hits merge in here.
  2340  			b := s.endBlock()
  2341  			b.Kind = ssa.BlockPlain
  2342  			b.AddEdgeTo(merge)
  2343  			s.startBlock(merge)
  2344  		}
  2345  
  2346  	case ir.OCHECKNIL:
  2347  		n := n.(*ir.UnaryExpr)
  2348  		p := s.expr(n.X)
  2349  		_ = s.nilCheck(p)
  2350  		// TODO: check that throwing away the nilcheck result is ok.
  2351  
  2352  	case ir.OINLMARK:
  2353  		n := n.(*ir.InlineMarkStmt)
  2354  		s.newValue1I(ssa.OpInlMark, types.TypeVoid, n.Index, s.mem())
  2355  
  2356  	default:
  2357  		s.Fatalf("unhandled stmt %v", n.Op())
  2358  	}
  2359  }
  2360  
  2361  // If true, share as many open-coded defer exits as possible (with the downside of
  2362  // worse line-number information)
  2363  const shareDeferExits = false
  2364  
  2365  // exit processes any code that needs to be generated just before returning.
  2366  // It returns a BlockRet block that ends the control flow. Its control value
  2367  // will be set to the final memory state.
  2368  func (s *state) exit() *ssa.Block {
  2369  	if s.hasdefer {
  2370  		if s.hasOpenDefers {
  2371  			if shareDeferExits && s.lastDeferExit != nil && len(s.openDefers) == s.lastDeferCount {
  2372  				if s.curBlock.Kind != ssa.BlockPlain {
  2373  					panic("Block for an exit should be BlockPlain")
  2374  				}
  2375  				s.curBlock.AddEdgeTo(s.lastDeferExit)
  2376  				s.endBlock()
  2377  				return s.lastDeferFinalBlock
  2378  			}
  2379  			s.openDeferExit()
  2380  		} else {
  2381  			// Shared deferreturn is assigned the "last" position in the function.
  2382  			// The linker picks the first deferreturn call it sees, so this is
  2383  			// the only sensible "shared" place.
  2384  			// To not-share deferreturn, the protocol would need to be changed
  2385  			// so that the call to deferproc-etc would receive the PC offset from
  2386  			// the return PC, and the runtime would need to use that instead of
  2387  			// the deferreturn retrieved from the pcln information.
  2388  			// opendefers would remain a problem, however.
  2389  			s.pushLine(s.curfn.Endlineno)
  2390  			s.rtcall(ir.Syms.Deferreturn, true, nil)
  2391  			s.popLine()
  2392  		}
  2393  	}
  2394  
  2395  	// Do actual return.
  2396  	// These currently turn into self-copies (in many cases).
  2397  	resultFields := s.curfn.Type().Results()
  2398  	results := make([]*ssa.Value, len(resultFields)+1, len(resultFields)+1)
  2399  	// Store SSAable and heap-escaped PPARAMOUT variables back to stack locations.
  2400  	for i, f := range resultFields {
  2401  		n := f.Nname.(*ir.Name)
  2402  		if s.canSSA(n) { // result is in some SSA variable
  2403  			if !n.IsOutputParamInRegisters() && n.Type().HasPointers() {
  2404  				// We are about to store to the result slot.
  2405  				s.vars[memVar] = s.newValue1A(ssa.OpVarDef, types.TypeMem, n, s.mem())
  2406  			}
  2407  			results[i] = s.variable(n, n.Type())
  2408  		} else if !n.OnStack() { // result is actually heap allocated
  2409  			// We are about to copy the in-heap result to the result slot.
  2410  			if n.Type().HasPointers() {
  2411  				s.vars[memVar] = s.newValue1A(ssa.OpVarDef, types.TypeMem, n, s.mem())
  2412  			}
  2413  			ha := s.expr(n.Heapaddr)
  2414  			s.instrumentFields(n.Type(), ha, instrumentRead)
  2415  			results[i] = s.newValue2(ssa.OpDereference, n.Type(), ha, s.mem())
  2416  		} else { // result is not SSA-able; not escaped, so not on heap, but too large for SSA.
  2417  			// Before register ABI this ought to be a self-move, home=dest,
  2418  			// With register ABI, it's still a self-move if parameter is on stack (i.e., too big or overflowed)
  2419  			// No VarDef, as the result slot is already holding live value.
  2420  			results[i] = s.newValue2(ssa.OpDereference, n.Type(), s.addr(n), s.mem())
  2421  		}
  2422  	}
  2423  
  2424  	// In -race mode, we need to call racefuncexit.
  2425  	// Note: This has to happen after we load any heap-allocated results,
  2426  	// otherwise races will be attributed to the caller instead.
  2427  	if s.instrumentEnterExit {
  2428  		s.rtcall(ir.Syms.Racefuncexit, true, nil)
  2429  	}
  2430  
  2431  	results[len(results)-1] = s.mem()
  2432  	m := s.newValue0(ssa.OpMakeResult, s.f.OwnAux.LateExpansionResultType())
  2433  	m.AddArgs(results...)
  2434  
  2435  	b := s.endBlock()
  2436  	b.Kind = ssa.BlockRet
  2437  	b.SetControl(m)
  2438  	if s.hasdefer && s.hasOpenDefers {
  2439  		s.lastDeferFinalBlock = b
  2440  	}
  2441  	return b
  2442  }
  2443  
  2444  type opAndType struct {
  2445  	op    ir.Op
  2446  	etype types.Kind
  2447  }
  2448  
  2449  var opToSSA = map[opAndType]ssa.Op{
  2450  	{ir.OADD, types.TINT8}:    ssa.OpAdd8,
  2451  	{ir.OADD, types.TUINT8}:   ssa.OpAdd8,
  2452  	{ir.OADD, types.TINT16}:   ssa.OpAdd16,
  2453  	{ir.OADD, types.TUINT16}:  ssa.OpAdd16,
  2454  	{ir.OADD, types.TINT32}:   ssa.OpAdd32,
  2455  	{ir.OADD, types.TUINT32}:  ssa.OpAdd32,
  2456  	{ir.OADD, types.TINT64}:   ssa.OpAdd64,
  2457  	{ir.OADD, types.TUINT64}:  ssa.OpAdd64,
  2458  	{ir.OADD, types.TFLOAT32}: ssa.OpAdd32F,
  2459  	{ir.OADD, types.TFLOAT64}: ssa.OpAdd64F,
  2460  
  2461  	{ir.OSUB, types.TINT8}:    ssa.OpSub8,
  2462  	{ir.OSUB, types.TUINT8}:   ssa.OpSub8,
  2463  	{ir.OSUB, types.TINT16}:   ssa.OpSub16,
  2464  	{ir.OSUB, types.TUINT16}:  ssa.OpSub16,
  2465  	{ir.OSUB, types.TINT32}:   ssa.OpSub32,
  2466  	{ir.OSUB, types.TUINT32}:  ssa.OpSub32,
  2467  	{ir.OSUB, types.TINT64}:   ssa.OpSub64,
  2468  	{ir.OSUB, types.TUINT64}:  ssa.OpSub64,
  2469  	{ir.OSUB, types.TFLOAT32}: ssa.OpSub32F,
  2470  	{ir.OSUB, types.TFLOAT64}: ssa.OpSub64F,
  2471  
  2472  	{ir.ONOT, types.TBOOL}: ssa.OpNot,
  2473  
  2474  	{ir.ONEG, types.TINT8}:    ssa.OpNeg8,
  2475  	{ir.ONEG, types.TUINT8}:   ssa.OpNeg8,
  2476  	{ir.ONEG, types.TINT16}:   ssa.OpNeg16,
  2477  	{ir.ONEG, types.TUINT16}:  ssa.OpNeg16,
  2478  	{ir.ONEG, types.TINT32}:   ssa.OpNeg32,
  2479  	{ir.ONEG, types.TUINT32}:  ssa.OpNeg32,
  2480  	{ir.ONEG, types.TINT64}:   ssa.OpNeg64,
  2481  	{ir.ONEG, types.TUINT64}:  ssa.OpNeg64,
  2482  	{ir.ONEG, types.TFLOAT32}: ssa.OpNeg32F,
  2483  	{ir.ONEG, types.TFLOAT64}: ssa.OpNeg64F,
  2484  
  2485  	{ir.OBITNOT, types.TINT8}:   ssa.OpCom8,
  2486  	{ir.OBITNOT, types.TUINT8}:  ssa.OpCom8,
  2487  	{ir.OBITNOT, types.TINT16}:  ssa.OpCom16,
  2488  	{ir.OBITNOT, types.TUINT16}: ssa.OpCom16,
  2489  	{ir.OBITNOT, types.TINT32}:  ssa.OpCom32,
  2490  	{ir.OBITNOT, types.TUINT32}: ssa.OpCom32,
  2491  	{ir.OBITNOT, types.TINT64}:  ssa.OpCom64,
  2492  	{ir.OBITNOT, types.TUINT64}: ssa.OpCom64,
  2493  
  2494  	{ir.OIMAG, types.TCOMPLEX64}:  ssa.OpComplexImag,
  2495  	{ir.OIMAG, types.TCOMPLEX128}: ssa.OpComplexImag,
  2496  	{ir.OREAL, types.TCOMPLEX64}:  ssa.OpComplexReal,
  2497  	{ir.OREAL, types.TCOMPLEX128}: ssa.OpComplexReal,
  2498  
  2499  	{ir.OMUL, types.TINT8}:    ssa.OpMul8,
  2500  	{ir.OMUL, types.TUINT8}:   ssa.OpMul8,
  2501  	{ir.OMUL, types.TINT16}:   ssa.OpMul16,
  2502  	{ir.OMUL, types.TUINT16}:  ssa.OpMul16,
  2503  	{ir.OMUL, types.TINT32}:   ssa.OpMul32,
  2504  	{ir.OMUL, types.TUINT32}:  ssa.OpMul32,
  2505  	{ir.OMUL, types.TINT64}:   ssa.OpMul64,
  2506  	{ir.OMUL, types.TUINT64}:  ssa.OpMul64,
  2507  	{ir.OMUL, types.TFLOAT32}: ssa.OpMul32F,
  2508  	{ir.OMUL, types.TFLOAT64}: ssa.OpMul64F,
  2509  
  2510  	{ir.ODIV, types.TFLOAT32}: ssa.OpDiv32F,
  2511  	{ir.ODIV, types.TFLOAT64}: ssa.OpDiv64F,
  2512  
  2513  	{ir.ODIV, types.TINT8}:   ssa.OpDiv8,
  2514  	{ir.ODIV, types.TUINT8}:  ssa.OpDiv8u,
  2515  	{ir.ODIV, types.TINT16}:  ssa.OpDiv16,
  2516  	{ir.ODIV, types.TUINT16}: ssa.OpDiv16u,
  2517  	{ir.ODIV, types.TINT32}:  ssa.OpDiv32,
  2518  	{ir.ODIV, types.TUINT32}: ssa.OpDiv32u,
  2519  	{ir.ODIV, types.TINT64}:  ssa.OpDiv64,
  2520  	{ir.ODIV, types.TUINT64}: ssa.OpDiv64u,
  2521  
  2522  	{ir.OMOD, types.TINT8}:   ssa.OpMod8,
  2523  	{ir.OMOD, types.TUINT8}:  ssa.OpMod8u,
  2524  	{ir.OMOD, types.TINT16}:  ssa.OpMod16,
  2525  	{ir.OMOD, types.TUINT16}: ssa.OpMod16u,
  2526  	{ir.OMOD, types.TINT32}:  ssa.OpMod32,
  2527  	{ir.OMOD, types.TUINT32}: ssa.OpMod32u,
  2528  	{ir.OMOD, types.TINT64}:  ssa.OpMod64,
  2529  	{ir.OMOD, types.TUINT64}: ssa.OpMod64u,
  2530  
  2531  	{ir.OAND, types.TINT8}:   ssa.OpAnd8,
  2532  	{ir.OAND, types.TUINT8}:  ssa.OpAnd8,
  2533  	{ir.OAND, types.TINT16}:  ssa.OpAnd16,
  2534  	{ir.OAND, types.TUINT16}: ssa.OpAnd16,
  2535  	{ir.OAND, types.TINT32}:  ssa.OpAnd32,
  2536  	{ir.OAND, types.TUINT32}: ssa.OpAnd32,
  2537  	{ir.OAND, types.TINT64}:  ssa.OpAnd64,
  2538  	{ir.OAND, types.TUINT64}: ssa.OpAnd64,
  2539  
  2540  	{ir.OOR, types.TINT8}:   ssa.OpOr8,
  2541  	{ir.OOR, types.TUINT8}:  ssa.OpOr8,
  2542  	{ir.OOR, types.TINT16}:  ssa.OpOr16,
  2543  	{ir.OOR, types.TUINT16}: ssa.OpOr16,
  2544  	{ir.OOR, types.TINT32}:  ssa.OpOr32,
  2545  	{ir.OOR, types.TUINT32}: ssa.OpOr32,
  2546  	{ir.OOR, types.TINT64}:  ssa.OpOr64,
  2547  	{ir.OOR, types.TUINT64}: ssa.OpOr64,
  2548  
  2549  	{ir.OXOR, types.TINT8}:   ssa.OpXor8,
  2550  	{ir.OXOR, types.TUINT8}:  ssa.OpXor8,
  2551  	{ir.OXOR, types.TINT16}:  ssa.OpXor16,
  2552  	{ir.OXOR, types.TUINT16}: ssa.OpXor16,
  2553  	{ir.OXOR, types.TINT32}:  ssa.OpXor32,
  2554  	{ir.OXOR, types.TUINT32}: ssa.OpXor32,
  2555  	{ir.OXOR, types.TINT64}:  ssa.OpXor64,
  2556  	{ir.OXOR, types.TUINT64}: ssa.OpXor64,
  2557  
  2558  	{ir.OEQ, types.TBOOL}:      ssa.OpEqB,
  2559  	{ir.OEQ, types.TINT8}:      ssa.OpEq8,
  2560  	{ir.OEQ, types.TUINT8}:     ssa.OpEq8,
  2561  	{ir.OEQ, types.TINT16}:     ssa.OpEq16,
  2562  	{ir.OEQ, types.TUINT16}:    ssa.OpEq16,
  2563  	{ir.OEQ, types.TINT32}:     ssa.OpEq32,
  2564  	{ir.OEQ, types.TUINT32}:    ssa.OpEq32,
  2565  	{ir.OEQ, types.TINT64}:     ssa.OpEq64,
  2566  	{ir.OEQ, types.TUINT64}:    ssa.OpEq64,
  2567  	{ir.OEQ, types.TINTER}:     ssa.OpEqInter,
  2568  	{ir.OEQ, types.TSLICE}:     ssa.OpEqSlice,
  2569  	{ir.OEQ, types.TFUNC}:      ssa.OpEqPtr,
  2570  	{ir.OEQ, types.TMAP}:       ssa.OpEqPtr,
  2571  	{ir.OEQ, types.TCHAN}:      ssa.OpEqPtr,
  2572  	{ir.OEQ, types.TPTR}:       ssa.OpEqPtr,
  2573  	{ir.OEQ, types.TUINTPTR}:   ssa.OpEqPtr,
  2574  	{ir.OEQ, types.TUNSAFEPTR}: ssa.OpEqPtr,
  2575  	{ir.OEQ, types.TFLOAT64}:   ssa.OpEq64F,
  2576  	{ir.OEQ, types.TFLOAT32}:   ssa.OpEq32F,
  2577  
  2578  	{ir.ONE, types.TBOOL}:      ssa.OpNeqB,
  2579  	{ir.ONE, types.TINT8}:      ssa.OpNeq8,
  2580  	{ir.ONE, types.TUINT8}:     ssa.OpNeq8,
  2581  	{ir.ONE, types.TINT16}:     ssa.OpNeq16,
  2582  	{ir.ONE, types.TUINT16}:    ssa.OpNeq16,
  2583  	{ir.ONE, types.TINT32}:     ssa.OpNeq32,
  2584  	{ir.ONE, types.TUINT32}:    ssa.OpNeq32,
  2585  	{ir.ONE, types.TINT64}:     ssa.OpNeq64,
  2586  	{ir.ONE, types.TUINT64}:    ssa.OpNeq64,
  2587  	{ir.ONE, types.TINTER}:     ssa.OpNeqInter,
  2588  	{ir.ONE, types.TSLICE}:     ssa.OpNeqSlice,
  2589  	{ir.ONE, types.TFUNC}:      ssa.OpNeqPtr,
  2590  	{ir.ONE, types.TMAP}:       ssa.OpNeqPtr,
  2591  	{ir.ONE, types.TCHAN}:      ssa.OpNeqPtr,
  2592  	{ir.ONE, types.TPTR}:       ssa.OpNeqPtr,
  2593  	{ir.ONE, types.TUINTPTR}:   ssa.OpNeqPtr,
  2594  	{ir.ONE, types.TUNSAFEPTR}: ssa.OpNeqPtr,
  2595  	{ir.ONE, types.TFLOAT64}:   ssa.OpNeq64F,
  2596  	{ir.ONE, types.TFLOAT32}:   ssa.OpNeq32F,
  2597  
  2598  	{ir.OLT, types.TINT8}:    ssa.OpLess8,
  2599  	{ir.OLT, types.TUINT8}:   ssa.OpLess8U,
  2600  	{ir.OLT, types.TINT16}:   ssa.OpLess16,
  2601  	{ir.OLT, types.TUINT16}:  ssa.OpLess16U,
  2602  	{ir.OLT, types.TINT32}:   ssa.OpLess32,
  2603  	{ir.OLT, types.TUINT32}:  ssa.OpLess32U,
  2604  	{ir.OLT, types.TINT64}:   ssa.OpLess64,
  2605  	{ir.OLT, types.TUINT64}:  ssa.OpLess64U,
  2606  	{ir.OLT, types.TFLOAT64}: ssa.OpLess64F,
  2607  	{ir.OLT, types.TFLOAT32}: ssa.OpLess32F,
  2608  
  2609  	{ir.OLE, types.TINT8}:    ssa.OpLeq8,
  2610  	{ir.OLE, types.TUINT8}:   ssa.OpLeq8U,
  2611  	{ir.OLE, types.TINT16}:   ssa.OpLeq16,
  2612  	{ir.OLE, types.TUINT16}:  ssa.OpLeq16U,
  2613  	{ir.OLE, types.TINT32}:   ssa.OpLeq32,
  2614  	{ir.OLE, types.TUINT32}:  ssa.OpLeq32U,
  2615  	{ir.OLE, types.TINT64}:   ssa.OpLeq64,
  2616  	{ir.OLE, types.TUINT64}:  ssa.OpLeq64U,
  2617  	{ir.OLE, types.TFLOAT64}: ssa.OpLeq64F,
  2618  	{ir.OLE, types.TFLOAT32}: ssa.OpLeq32F,
  2619  }
  2620  
  2621  func (s *state) concreteEtype(t *types.Type) types.Kind {
  2622  	e := t.Kind()
  2623  	switch e {
  2624  	default:
  2625  		return e
  2626  	case types.TINT:
  2627  		if s.config.PtrSize == 8 {
  2628  			return types.TINT64
  2629  		}
  2630  		return types.TINT32
  2631  	case types.TUINT:
  2632  		if s.config.PtrSize == 8 {
  2633  			return types.TUINT64
  2634  		}
  2635  		return types.TUINT32
  2636  	case types.TUINTPTR:
  2637  		if s.config.PtrSize == 8 {
  2638  			return types.TUINT64
  2639  		}
  2640  		return types.TUINT32
  2641  	}
  2642  }
  2643  
  2644  func (s *state) ssaOp(op ir.Op, t *types.Type) ssa.Op {
  2645  	etype := s.concreteEtype(t)
  2646  	x, ok := opToSSA[opAndType{op, etype}]
  2647  	if !ok {
  2648  		s.Fatalf("unhandled binary op %v %s", op, etype)
  2649  	}
  2650  	return x
  2651  }
  2652  
  2653  type opAndTwoTypes struct {
  2654  	op     ir.Op
  2655  	etype1 types.Kind
  2656  	etype2 types.Kind
  2657  }
  2658  
  2659  type twoTypes struct {
  2660  	etype1 types.Kind
  2661  	etype2 types.Kind
  2662  }
  2663  
  2664  type twoOpsAndType struct {
  2665  	op1              ssa.Op
  2666  	op2              ssa.Op
  2667  	intermediateType types.Kind
  2668  }
  2669  
  2670  var fpConvOpToSSA = map[twoTypes]twoOpsAndType{
  2671  
  2672  	{types.TINT8, types.TFLOAT32}:  {ssa.OpSignExt8to32, ssa.OpCvt32to32F, types.TINT32},
  2673  	{types.TINT16, types.TFLOAT32}: {ssa.OpSignExt16to32, ssa.OpCvt32to32F, types.TINT32},
  2674  	{types.TINT32, types.TFLOAT32}: {ssa.OpCopy, ssa.OpCvt32to32F, types.TINT32},
  2675  	{types.TINT64, types.TFLOAT32}: {ssa.OpCopy, ssa.OpCvt64to32F, types.TINT64},
  2676  
  2677  	{types.TINT8, types.TFLOAT64}:  {ssa.OpSignExt8to32, ssa.OpCvt32to64F, types.TINT32},
  2678  	{types.TINT16, types.TFLOAT64}: {ssa.OpSignExt16to32, ssa.OpCvt32to64F, types.TINT32},
  2679  	{types.TINT32, types.TFLOAT64}: {ssa.OpCopy, ssa.OpCvt32to64F, types.TINT32},
  2680  	{types.TINT64, types.TFLOAT64}: {ssa.OpCopy, ssa.OpCvt64to64F, types.TINT64},
  2681  
  2682  	{types.TFLOAT32, types.TINT8}:  {ssa.OpCvt32Fto32, ssa.OpTrunc32to8, types.TINT32},
  2683  	{types.TFLOAT32, types.TINT16}: {ssa.OpCvt32Fto32, ssa.OpTrunc32to16, types.TINT32},
  2684  	{types.TFLOAT32, types.TINT32}: {ssa.OpCvt32Fto32, ssa.OpCopy, types.TINT32},
  2685  	{types.TFLOAT32, types.TINT64}: {ssa.OpCvt32Fto64, ssa.OpCopy, types.TINT64},
  2686  
  2687  	{types.TFLOAT64, types.TINT8}:  {ssa.OpCvt64Fto32, ssa.OpTrunc32to8, types.TINT32},
  2688  	{types.TFLOAT64, types.TINT16}: {ssa.OpCvt64Fto32, ssa.OpTrunc32to16, types.TINT32},
  2689  	{types.TFLOAT64, types.TINT32}: {ssa.OpCvt64Fto32, ssa.OpCopy, types.TINT32},
  2690  	{types.TFLOAT64, types.TINT64}: {ssa.OpCvt64Fto64, ssa.OpCopy, types.TINT64},
  2691  	// unsigned
  2692  	{types.TUINT8, types.TFLOAT32}:  {ssa.OpZeroExt8to32, ssa.OpCvt32to32F, types.TINT32},
  2693  	{types.TUINT16, types.TFLOAT32}: {ssa.OpZeroExt16to32, ssa.OpCvt32to32F, types.TINT32},
  2694  	{types.TUINT32, types.TFLOAT32}: {ssa.OpZeroExt32to64, ssa.OpCvt64to32F, types.TINT64}, // go wide to dodge unsigned
  2695  	{types.TUINT64, types.TFLOAT32}: {ssa.OpCopy, ssa.OpInvalid, types.TUINT64},            // Cvt64Uto32F, branchy code expansion instead
  2696  
  2697  	{types.TUINT8, types.TFLOAT64}:  {ssa.OpZeroExt8to32, ssa.OpCvt32to64F, types.TINT32},
  2698  	{types.TUINT16, types.TFLOAT64}: {ssa.OpZeroExt16to32, ssa.OpCvt32to64F, types.TINT32},
  2699  	{types.TUINT32, types.TFLOAT64}: {ssa.OpZeroExt32to64, ssa.OpCvt64to64F, types.TINT64}, // go wide to dodge unsigned
  2700  	{types.TUINT64, types.TFLOAT64}: {ssa.OpCopy, ssa.OpInvalid, types.TUINT64},            // Cvt64Uto64F, branchy code expansion instead
  2701  
  2702  	{types.TFLOAT32, types.TUINT8}:  {ssa.OpCvt32Fto32, ssa.OpTrunc32to8, types.TINT32},
  2703  	{types.TFLOAT32, types.TUINT16}: {ssa.OpCvt32Fto32, ssa.OpTrunc32to16, types.TINT32},
  2704  	{types.TFLOAT32, types.TUINT32}: {ssa.OpInvalid, ssa.OpCopy, types.TINT64},  // Cvt64Fto32U, branchy code expansion instead
  2705  	{types.TFLOAT32, types.TUINT64}: {ssa.OpInvalid, ssa.OpCopy, types.TUINT64}, // Cvt32Fto64U, branchy code expansion instead
  2706  
  2707  	{types.TFLOAT64, types.TUINT8}:  {ssa.OpCvt64Fto32, ssa.OpTrunc32to8, types.TINT32},
  2708  	{types.TFLOAT64, types.TUINT16}: {ssa.OpCvt64Fto32, ssa.OpTrunc32to16, types.TINT32},
  2709  	{types.TFLOAT64, types.TUINT32}: {ssa.OpInvalid, ssa.OpCopy, types.TINT64},  // Cvt64Fto32U, branchy code expansion instead
  2710  	{types.TFLOAT64, types.TUINT64}: {ssa.OpInvalid, ssa.OpCopy, types.TUINT64}, // Cvt64Fto64U, branchy code expansion instead
  2711  
  2712  	// float
  2713  	{types.TFLOAT64, types.TFLOAT32}: {ssa.OpCvt64Fto32F, ssa.OpCopy, types.TFLOAT32},
  2714  	{types.TFLOAT64, types.TFLOAT64}: {ssa.OpRound64F, ssa.OpCopy, types.TFLOAT64},
  2715  	{types.TFLOAT32, types.TFLOAT32}: {ssa.OpRound32F, ssa.OpCopy, types.TFLOAT32},
  2716  	{types.TFLOAT32, types.TFLOAT64}: {ssa.OpCvt32Fto64F, ssa.OpCopy, types.TFLOAT64},
  2717  }
  2718  
  2719  // this map is used only for 32-bit arch, and only includes the difference
  2720  // on 32-bit arch, don't use int64<->float conversion for uint32
  2721  var fpConvOpToSSA32 = map[twoTypes]twoOpsAndType{
  2722  	{types.TUINT32, types.TFLOAT32}: {ssa.OpCopy, ssa.OpCvt32Uto32F, types.TUINT32},
  2723  	{types.TUINT32, types.TFLOAT64}: {ssa.OpCopy, ssa.OpCvt32Uto64F, types.TUINT32},
  2724  	{types.TFLOAT32, types.TUINT32}: {ssa.OpCvt32Fto32U, ssa.OpCopy, types.TUINT32},
  2725  	{types.TFLOAT64, types.TUINT32}: {ssa.OpCvt64Fto32U, ssa.OpCopy, types.TUINT32},
  2726  }
  2727  
  2728  // uint64<->float conversions, only on machines that have instructions for that
  2729  var uint64fpConvOpToSSA = map[twoTypes]twoOpsAndType{
  2730  	{types.TUINT64, types.TFLOAT32}: {ssa.OpCopy, ssa.OpCvt64Uto32F, types.TUINT64},
  2731  	{types.TUINT64, types.TFLOAT64}: {ssa.OpCopy, ssa.OpCvt64Uto64F, types.TUINT64},
  2732  	{types.TFLOAT32, types.TUINT64}: {ssa.OpCvt32Fto64U, ssa.OpCopy, types.TUINT64},
  2733  	{types.TFLOAT64, types.TUINT64}: {ssa.OpCvt64Fto64U, ssa.OpCopy, types.TUINT64},
  2734  }
  2735  
  2736  var shiftOpToSSA = map[opAndTwoTypes]ssa.Op{
  2737  	{ir.OLSH, types.TINT8, types.TUINT8}:   ssa.OpLsh8x8,
  2738  	{ir.OLSH, types.TUINT8, types.TUINT8}:  ssa.OpLsh8x8,
  2739  	{ir.OLSH, types.TINT8, types.TUINT16}:  ssa.OpLsh8x16,
  2740  	{ir.OLSH, types.TUINT8, types.TUINT16}: ssa.OpLsh8x16,
  2741  	{ir.OLSH, types.TINT8, types.TUINT32}:  ssa.OpLsh8x32,
  2742  	{ir.OLSH, types.TUINT8, types.TUINT32}: ssa.OpLsh8x32,
  2743  	{ir.OLSH, types.TINT8, types.TUINT64}:  ssa.OpLsh8x64,
  2744  	{ir.OLSH, types.TUINT8, types.TUINT64}: ssa.OpLsh8x64,
  2745  
  2746  	{ir.OLSH, types.TINT16, types.TUINT8}:   ssa.OpLsh16x8,
  2747  	{ir.OLSH, types.TUINT16, types.TUINT8}:  ssa.OpLsh16x8,
  2748  	{ir.OLSH, types.TINT16, types.TUINT16}:  ssa.OpLsh16x16,
  2749  	{ir.OLSH, types.TUINT16, types.TUINT16}: ssa.OpLsh16x16,
  2750  	{ir.OLSH, types.TINT16, types.TUINT32}:  ssa.OpLsh16x32,
  2751  	{ir.OLSH, types.TUINT16, types.TUINT32}: ssa.OpLsh16x32,
  2752  	{ir.OLSH, types.TINT16, types.TUINT64}:  ssa.OpLsh16x64,
  2753  	{ir.OLSH, types.TUINT16, types.TUINT64}: ssa.OpLsh16x64,
  2754  
  2755  	{ir.OLSH, types.TINT32, types.TUINT8}:   ssa.OpLsh32x8,
  2756  	{ir.OLSH, types.TUINT32, types.TUINT8}:  ssa.OpLsh32x8,
  2757  	{ir.OLSH, types.TINT32, types.TUINT16}:  ssa.OpLsh32x16,
  2758  	{ir.OLSH, types.TUINT32, types.TUINT16}: ssa.OpLsh32x16,
  2759  	{ir.OLSH, types.TINT32, types.TUINT32}:  ssa.OpLsh32x32,
  2760  	{ir.OLSH, types.TUINT32, types.TUINT32}: ssa.OpLsh32x32,
  2761  	{ir.OLSH, types.TINT32, types.TUINT64}:  ssa.OpLsh32x64,
  2762  	{ir.OLSH, types.TUINT32, types.TUINT64}: ssa.OpLsh32x64,
  2763  
  2764  	{ir.OLSH, types.TINT64, types.TUINT8}:   ssa.OpLsh64x8,
  2765  	{ir.OLSH, types.TUINT64, types.TUINT8}:  ssa.OpLsh64x8,
  2766  	{ir.OLSH, types.TINT64, types.TUINT16}:  ssa.OpLsh64x16,
  2767  	{ir.OLSH, types.TUINT64, types.TUINT16}: ssa.OpLsh64x16,
  2768  	{ir.OLSH, types.TINT64, types.TUINT32}:  ssa.OpLsh64x32,
  2769  	{ir.OLSH, types.TUINT64, types.TUINT32}: ssa.OpLsh64x32,
  2770  	{ir.OLSH, types.TINT64, types.TUINT64}:  ssa.OpLsh64x64,
  2771  	{ir.OLSH, types.TUINT64, types.TUINT64}: ssa.OpLsh64x64,
  2772  
  2773  	{ir.ORSH, types.TINT8, types.TUINT8}:   ssa.OpRsh8x8,
  2774  	{ir.ORSH, types.TUINT8, types.TUINT8}:  ssa.OpRsh8Ux8,
  2775  	{ir.ORSH, types.TINT8, types.TUINT16}:  ssa.OpRsh8x16,
  2776  	{ir.ORSH, types.TUINT8, types.TUINT16}: ssa.OpRsh8Ux16,
  2777  	{ir.ORSH, types.TINT8, types.TUINT32}:  ssa.OpRsh8x32,
  2778  	{ir.ORSH, types.TUINT8, types.TUINT32}: ssa.OpRsh8Ux32,
  2779  	{ir.ORSH, types.TINT8, types.TUINT64}:  ssa.OpRsh8x64,
  2780  	{ir.ORSH, types.TUINT8, types.TUINT64}: ssa.OpRsh8Ux64,
  2781  
  2782  	{ir.ORSH, types.TINT16, types.TUINT8}:   ssa.OpRsh16x8,
  2783  	{ir.ORSH, types.TUINT16, types.TUINT8}:  ssa.OpRsh16Ux8,
  2784  	{ir.ORSH, types.TINT16, types.TUINT16}:  ssa.OpRsh16x16,
  2785  	{ir.ORSH, types.TUINT16, types.TUINT16}: ssa.OpRsh16Ux16,
  2786  	{ir.ORSH, types.TINT16, types.TUINT32}:  ssa.OpRsh16x32,
  2787  	{ir.ORSH, types.TUINT16, types.TUINT32}: ssa.OpRsh16Ux32,
  2788  	{ir.ORSH, types.TINT16, types.TUINT64}:  ssa.OpRsh16x64,
  2789  	{ir.ORSH, types.TUINT16, types.TUINT64}: ssa.OpRsh16Ux64,
  2790  
  2791  	{ir.ORSH, types.TINT32, types.TUINT8}:   ssa.OpRsh32x8,
  2792  	{ir.ORSH, types.TUINT32, types.TUINT8}:  ssa.OpRsh32Ux8,
  2793  	{ir.ORSH, types.TINT32, types.TUINT16}:  ssa.OpRsh32x16,
  2794  	{ir.ORSH, types.TUINT32, types.TUINT16}: ssa.OpRsh32Ux16,
  2795  	{ir.ORSH, types.TINT32, types.TUINT32}:  ssa.OpRsh32x32,
  2796  	{ir.ORSH, types.TUINT32, types.TUINT32}: ssa.OpRsh32Ux32,
  2797  	{ir.ORSH, types.TINT32, types.TUINT64}:  ssa.OpRsh32x64,
  2798  	{ir.ORSH, types.TUINT32, types.TUINT64}: ssa.OpRsh32Ux64,
  2799  
  2800  	{ir.ORSH, types.TINT64, types.TUINT8}:   ssa.OpRsh64x8,
  2801  	{ir.ORSH, types.TUINT64, types.TUINT8}:  ssa.OpRsh64Ux8,
  2802  	{ir.ORSH, types.TINT64, types.TUINT16}:  ssa.OpRsh64x16,
  2803  	{ir.ORSH, types.TUINT64, types.TUINT16}: ssa.OpRsh64Ux16,
  2804  	{ir.ORSH, types.TINT64, types.TUINT32}:  ssa.OpRsh64x32,
  2805  	{ir.ORSH, types.TUINT64, types.TUINT32}: ssa.OpRsh64Ux32,
  2806  	{ir.ORSH, types.TINT64, types.TUINT64}:  ssa.OpRsh64x64,
  2807  	{ir.ORSH, types.TUINT64, types.TUINT64}: ssa.OpRsh64Ux64,
  2808  }
  2809  
  2810  func (s *state) ssaShiftOp(op ir.Op, t *types.Type, u *types.Type) ssa.Op {
  2811  	etype1 := s.concreteEtype(t)
  2812  	etype2 := s.concreteEtype(u)
  2813  	x, ok := shiftOpToSSA[opAndTwoTypes{op, etype1, etype2}]
  2814  	if !ok {
  2815  		s.Fatalf("unhandled shift op %v etype=%s/%s", op, etype1, etype2)
  2816  	}
  2817  	return x
  2818  }
  2819  
  2820  func (s *state) uintptrConstant(v uint64) *ssa.Value {
  2821  	if s.config.PtrSize == 4 {
  2822  		return s.newValue0I(ssa.OpConst32, types.Types[types.TUINTPTR], int64(v))
  2823  	}
  2824  	return s.newValue0I(ssa.OpConst64, types.Types[types.TUINTPTR], int64(v))
  2825  }
  2826  
  2827  func (s *state) conv(n ir.Node, v *ssa.Value, ft, tt *types.Type) *ssa.Value {
  2828  	if ft.IsBoolean() && tt.IsKind(types.TUINT8) {
  2829  		// Bool -> uint8 is generated internally when indexing into runtime.staticbyte.
  2830  		return s.newValue1(ssa.OpCvtBoolToUint8, tt, v)
  2831  	}
  2832  	if ft.IsInteger() && tt.IsInteger() {
  2833  		var op ssa.Op
  2834  		if tt.Size() == ft.Size() {
  2835  			op = ssa.OpCopy
  2836  		} else if tt.Size() < ft.Size() {
  2837  			// truncation
  2838  			switch 10*ft.Size() + tt.Size() {
  2839  			case 21:
  2840  				op = ssa.OpTrunc16to8
  2841  			case 41:
  2842  				op = ssa.OpTrunc32to8
  2843  			case 42:
  2844  				op = ssa.OpTrunc32to16
  2845  			case 81:
  2846  				op = ssa.OpTrunc64to8
  2847  			case 82:
  2848  				op = ssa.OpTrunc64to16
  2849  			case 84:
  2850  				op = ssa.OpTrunc64to32
  2851  			default:
  2852  				s.Fatalf("weird integer truncation %v -> %v", ft, tt)
  2853  			}
  2854  		} else if ft.IsSigned() {
  2855  			// sign extension
  2856  			switch 10*ft.Size() + tt.Size() {
  2857  			case 12:
  2858  				op = ssa.OpSignExt8to16
  2859  			case 14:
  2860  				op = ssa.OpSignExt8to32
  2861  			case 18:
  2862  				op = ssa.OpSignExt8to64
  2863  			case 24:
  2864  				op = ssa.OpSignExt16to32
  2865  			case 28:
  2866  				op = ssa.OpSignExt16to64
  2867  			case 48:
  2868  				op = ssa.OpSignExt32to64
  2869  			default:
  2870  				s.Fatalf("bad integer sign extension %v -> %v", ft, tt)
  2871  			}
  2872  		} else {
  2873  			// zero extension
  2874  			switch 10*ft.Size() + tt.Size() {
  2875  			case 12:
  2876  				op = ssa.OpZeroExt8to16
  2877  			case 14:
  2878  				op = ssa.OpZeroExt8to32
  2879  			case 18:
  2880  				op = ssa.OpZeroExt8to64
  2881  			case 24:
  2882  				op = ssa.OpZeroExt16to32
  2883  			case 28:
  2884  				op = ssa.OpZeroExt16to64
  2885  			case 48:
  2886  				op = ssa.OpZeroExt32to64
  2887  			default:
  2888  				s.Fatalf("weird integer sign extension %v -> %v", ft, tt)
  2889  			}
  2890  		}
  2891  		return s.newValue1(op, tt, v)
  2892  	}
  2893  
  2894  	if ft.IsComplex() && tt.IsComplex() {
  2895  		var op ssa.Op
  2896  		if ft.Size() == tt.Size() {
  2897  			switch ft.Size() {
  2898  			case 8:
  2899  				op = ssa.OpRound32F
  2900  			case 16:
  2901  				op = ssa.OpRound64F
  2902  			default:
  2903  				s.Fatalf("weird complex conversion %v -> %v", ft, tt)
  2904  			}
  2905  		} else if ft.Size() == 8 && tt.Size() == 16 {
  2906  			op = ssa.OpCvt32Fto64F
  2907  		} else if ft.Size() == 16 && tt.Size() == 8 {
  2908  			op = ssa.OpCvt64Fto32F
  2909  		} else {
  2910  			s.Fatalf("weird complex conversion %v -> %v", ft, tt)
  2911  		}
  2912  		ftp := types.FloatForComplex(ft)
  2913  		ttp := types.FloatForComplex(tt)
  2914  		return s.newValue2(ssa.OpComplexMake, tt,
  2915  			s.newValueOrSfCall1(op, ttp, s.newValue1(ssa.OpComplexReal, ftp, v)),
  2916  			s.newValueOrSfCall1(op, ttp, s.newValue1(ssa.OpComplexImag, ftp, v)))
  2917  	}
  2918  
  2919  	if tt.IsComplex() { // and ft is not complex
  2920  		// Needed for generics support - can't happen in normal Go code.
  2921  		et := types.FloatForComplex(tt)
  2922  		v = s.conv(n, v, ft, et)
  2923  		return s.newValue2(ssa.OpComplexMake, tt, v, s.zeroVal(et))
  2924  	}
  2925  
  2926  	if ft.IsFloat() || tt.IsFloat() {
  2927  		cft, ctt := s.concreteEtype(ft), s.concreteEtype(tt)
  2928  		conv, ok := fpConvOpToSSA[twoTypes{cft, ctt}]
  2929  		// there's a change to a conversion-op table, this restores the old behavior if ConvertHash is false.
  2930  		// use salted hash to distinguish unsigned convert at a Pos from signed convert at a Pos
  2931  		if ctt == types.TUINT32 && ft.IsFloat() && !base.ConvertHash.MatchPosWithInfo(n.Pos(), "U", nil) {
  2932  			// revert to old behavior
  2933  			conv.op1 = ssa.OpCvt64Fto64
  2934  			if cft == types.TFLOAT32 {
  2935  				conv.op1 = ssa.OpCvt32Fto64
  2936  			}
  2937  			conv.op2 = ssa.OpTrunc64to32
  2938  
  2939  		}
  2940  		if s.config.RegSize == 4 && Arch.LinkArch.Family != sys.MIPS && !s.softFloat {
  2941  			if conv1, ok1 := fpConvOpToSSA32[twoTypes{s.concreteEtype(ft), s.concreteEtype(tt)}]; ok1 {
  2942  				conv = conv1
  2943  			}
  2944  		}
  2945  		if Arch.LinkArch.Family == sys.ARM64 || Arch.LinkArch.Family == sys.Wasm || Arch.LinkArch.Family == sys.S390X || s.softFloat {
  2946  			if conv1, ok1 := uint64fpConvOpToSSA[twoTypes{s.concreteEtype(ft), s.concreteEtype(tt)}]; ok1 {
  2947  				conv = conv1
  2948  			}
  2949  		}
  2950  
  2951  		if Arch.LinkArch.Family == sys.MIPS && !s.softFloat {
  2952  			if ft.Size() == 4 && ft.IsInteger() && !ft.IsSigned() {
  2953  				// tt is float32 or float64, and ft is also unsigned
  2954  				if tt.Size() == 4 {
  2955  					return s.uint32Tofloat32(n, v, ft, tt)
  2956  				}
  2957  				if tt.Size() == 8 {
  2958  					return s.uint32Tofloat64(n, v, ft, tt)
  2959  				}
  2960  			} else if tt.Size() == 4 && tt.IsInteger() && !tt.IsSigned() {
  2961  				// ft is float32 or float64, and tt is unsigned integer
  2962  				if ft.Size() == 4 {
  2963  					return s.float32ToUint32(n, v, ft, tt)
  2964  				}
  2965  				if ft.Size() == 8 {
  2966  					return s.float64ToUint32(n, v, ft, tt)
  2967  				}
  2968  			}
  2969  		}
  2970  
  2971  		if !ok {
  2972  			s.Fatalf("weird float conversion %v -> %v", ft, tt)
  2973  		}
  2974  		op1, op2, it := conv.op1, conv.op2, conv.intermediateType
  2975  
  2976  		if op1 != ssa.OpInvalid && op2 != ssa.OpInvalid {
  2977  			// normal case, not tripping over unsigned 64
  2978  			if op1 == ssa.OpCopy {
  2979  				if op2 == ssa.OpCopy {
  2980  					return v
  2981  				}
  2982  				return s.newValueOrSfCall1(op2, tt, v)
  2983  			}
  2984  			if op2 == ssa.OpCopy {
  2985  				return s.newValueOrSfCall1(op1, tt, v)
  2986  			}
  2987  			return s.newValueOrSfCall1(op2, tt, s.newValueOrSfCall1(op1, types.Types[it], v))
  2988  		}
  2989  		// Tricky 64-bit unsigned cases.
  2990  		if ft.IsInteger() {
  2991  			// tt is float32 or float64, and ft is also unsigned
  2992  			if tt.Size() == 4 {
  2993  				return s.uint64Tofloat32(n, v, ft, tt)
  2994  			}
  2995  			if tt.Size() == 8 {
  2996  				return s.uint64Tofloat64(n, v, ft, tt)
  2997  			}
  2998  			s.Fatalf("weird unsigned integer to float conversion %v -> %v", ft, tt)
  2999  		}
  3000  		// ft is float32 or float64, and tt is unsigned integer
  3001  		if ft.Size() == 4 {
  3002  			switch tt.Size() {
  3003  			case 8:
  3004  				return s.float32ToUint64(n, v, ft, tt)
  3005  			case 4, 2, 1:
  3006  				// TODO should 2 and 1 saturate or truncate?
  3007  				return s.float32ToUint32(n, v, ft, tt)
  3008  			}
  3009  		}
  3010  		if ft.Size() == 8 {
  3011  			switch tt.Size() {
  3012  			case 8:
  3013  				return s.float64ToUint64(n, v, ft, tt)
  3014  			case 4, 2, 1:
  3015  				// TODO should 2 and 1 saturate or truncate?
  3016  				return s.float64ToUint32(n, v, ft, tt)
  3017  			}
  3018  
  3019  		}
  3020  		s.Fatalf("weird float to unsigned integer conversion %v -> %v", ft, tt)
  3021  		return nil
  3022  	}
  3023  
  3024  	s.Fatalf("unhandled OCONV %s -> %s", ft.Kind(), tt.Kind())
  3025  	return nil
  3026  }
  3027  
  3028  // expr converts the expression n to ssa, adds it to s and returns the ssa result.
  3029  func (s *state) expr(n ir.Node) *ssa.Value {
  3030  	return s.exprCheckPtr(n, true)
  3031  }
  3032  
  3033  func (s *state) exprCheckPtr(n ir.Node, checkPtrOK bool) *ssa.Value {
  3034  	if ir.HasUniquePos(n) {
  3035  		// ONAMEs and named OLITERALs have the line number
  3036  		// of the decl, not the use. See issue 14742.
  3037  		s.pushLine(n.Pos())
  3038  		defer s.popLine()
  3039  	}
  3040  
  3041  	s.stmtList(n.Init())
  3042  	switch n.Op() {
  3043  	case ir.OBYTES2STRTMP:
  3044  		n := n.(*ir.ConvExpr)
  3045  		slice := s.expr(n.X)
  3046  		ptr := s.newValue1(ssa.OpSlicePtr, s.f.Config.Types.BytePtr, slice)
  3047  		len := s.newValue1(ssa.OpSliceLen, types.Types[types.TINT], slice)
  3048  		return s.newValue2(ssa.OpStringMake, n.Type(), ptr, len)
  3049  	case ir.OSTR2BYTESTMP:
  3050  		n := n.(*ir.ConvExpr)
  3051  		str := s.expr(n.X)
  3052  		ptr := s.newValue1(ssa.OpStringPtr, s.f.Config.Types.BytePtr, str)
  3053  		if !n.NonNil() {
  3054  			// We need to ensure []byte("") evaluates to []byte{}, and not []byte(nil).
  3055  			//
  3056  			// TODO(mdempsky): Investigate using "len != 0" instead of "ptr != nil".
  3057  			cond := s.newValue2(ssa.OpNeqPtr, types.Types[types.TBOOL], ptr, s.constNil(ptr.Type))
  3058  			zerobase := s.newValue1A(ssa.OpAddr, ptr.Type, ir.Syms.Zerobase, s.sb)
  3059  			ptr = s.ternary(cond, ptr, zerobase)
  3060  		}
  3061  		len := s.newValue1(ssa.OpStringLen, types.Types[types.TINT], str)
  3062  		return s.newValue3(ssa.OpSliceMake, n.Type(), ptr, len, len)
  3063  	case ir.OCFUNC:
  3064  		n := n.(*ir.UnaryExpr)
  3065  		aux := n.X.(*ir.Name).Linksym()
  3066  		// OCFUNC is used to build function values, which must
  3067  		// always reference ABIInternal entry points.
  3068  		if aux.ABI() != obj.ABIInternal {
  3069  			s.Fatalf("expected ABIInternal: %v", aux.ABI())
  3070  		}
  3071  		return s.entryNewValue1A(ssa.OpAddr, n.Type(), aux, s.sb)
  3072  	case ir.ONAME:
  3073  		n := n.(*ir.Name)
  3074  		if n.Class == ir.PFUNC {
  3075  			// "value" of a function is the address of the function's closure
  3076  			sym := staticdata.FuncLinksym(n)
  3077  			return s.entryNewValue1A(ssa.OpAddr, types.NewPtr(n.Type()), sym, s.sb)
  3078  		}
  3079  		if s.canSSA(n) {
  3080  			return s.variable(n, n.Type())
  3081  		}
  3082  		return s.load(n.Type(), s.addr(n))
  3083  	case ir.OLINKSYMOFFSET:
  3084  		n := n.(*ir.LinksymOffsetExpr)
  3085  		return s.load(n.Type(), s.addr(n))
  3086  	case ir.ONIL:
  3087  		n := n.(*ir.NilExpr)
  3088  		t := n.Type()
  3089  		switch {
  3090  		case t.IsSlice():
  3091  			return s.constSlice(t)
  3092  		case t.IsInterface():
  3093  			return s.constInterface(t)
  3094  		default:
  3095  			return s.constNil(t)
  3096  		}
  3097  	case ir.OLITERAL:
  3098  		switch u := n.Val(); u.Kind() {
  3099  		case constant.Int:
  3100  			i := ir.IntVal(n.Type(), u)
  3101  			switch n.Type().Size() {
  3102  			case 1:
  3103  				return s.constInt8(n.Type(), int8(i))
  3104  			case 2:
  3105  				return s.constInt16(n.Type(), int16(i))
  3106  			case 4:
  3107  				return s.constInt32(n.Type(), int32(i))
  3108  			case 8:
  3109  				return s.constInt64(n.Type(), i)
  3110  			default:
  3111  				s.Fatalf("bad integer size %d", n.Type().Size())
  3112  				return nil
  3113  			}
  3114  		case constant.String:
  3115  			i := constant.StringVal(u)
  3116  			if i == "" {
  3117  				return s.constEmptyString(n.Type())
  3118  			}
  3119  			return s.entryNewValue0A(ssa.OpConstString, n.Type(), ssa.StringToAux(i))
  3120  		case constant.Bool:
  3121  			return s.constBool(constant.BoolVal(u))
  3122  		case constant.Float:
  3123  			f, _ := constant.Float64Val(u)
  3124  			switch n.Type().Size() {
  3125  			case 4:
  3126  				return s.constFloat32(n.Type(), f)
  3127  			case 8:
  3128  				return s.constFloat64(n.Type(), f)
  3129  			default:
  3130  				s.Fatalf("bad float size %d", n.Type().Size())
  3131  				return nil
  3132  			}
  3133  		case constant.Complex:
  3134  			re, _ := constant.Float64Val(constant.Real(u))
  3135  			im, _ := constant.Float64Val(constant.Imag(u))
  3136  			switch n.Type().Size() {
  3137  			case 8:
  3138  				pt := types.Types[types.TFLOAT32]
  3139  				return s.newValue2(ssa.OpComplexMake, n.Type(),
  3140  					s.constFloat32(pt, re),
  3141  					s.constFloat32(pt, im))
  3142  			case 16:
  3143  				pt := types.Types[types.TFLOAT64]
  3144  				return s.newValue2(ssa.OpComplexMake, n.Type(),
  3145  					s.constFloat64(pt, re),
  3146  					s.constFloat64(pt, im))
  3147  			default:
  3148  				s.Fatalf("bad complex size %d", n.Type().Size())
  3149  				return nil
  3150  			}
  3151  		default:
  3152  			s.Fatalf("unhandled OLITERAL %v", u.Kind())
  3153  			return nil
  3154  		}
  3155  	case ir.OCONVNOP:
  3156  		n := n.(*ir.ConvExpr)
  3157  		to := n.Type()
  3158  		from := n.X.Type()
  3159  
  3160  		// Assume everything will work out, so set up our return value.
  3161  		// Anything interesting that happens from here is a fatal.
  3162  		x := s.expr(n.X)
  3163  		if to == from {
  3164  			return x
  3165  		}
  3166  
  3167  		// Special case for not confusing GC and liveness.
  3168  		// We don't want pointers accidentally classified
  3169  		// as not-pointers or vice-versa because of copy
  3170  		// elision.
  3171  		if to.IsPtrShaped() != from.IsPtrShaped() {
  3172  			return s.newValue2(ssa.OpConvert, to, x, s.mem())
  3173  		}
  3174  
  3175  		v := s.newValue1(ssa.OpCopy, to, x) // ensure that v has the right type
  3176  
  3177  		// CONVNOP closure
  3178  		if to.Kind() == types.TFUNC && from.IsPtrShaped() {
  3179  			return v
  3180  		}
  3181  
  3182  		// named <--> unnamed type or typed <--> untyped const
  3183  		if from.Kind() == to.Kind() {
  3184  			return v
  3185  		}
  3186  
  3187  		// unsafe.Pointer <--> *T
  3188  		if to.IsUnsafePtr() && from.IsPtrShaped() || from.IsUnsafePtr() && to.IsPtrShaped() {
  3189  			if s.checkPtrEnabled && checkPtrOK && to.IsPtr() && from.IsUnsafePtr() {
  3190  				s.checkPtrAlignment(n, v, nil)
  3191  			}
  3192  			return v
  3193  		}
  3194  
  3195  		// map <--> *internal/runtime/maps.Map
  3196  		mt := types.NewPtr(reflectdata.MapType())
  3197  		if to.Kind() == types.TMAP && from == mt {
  3198  			return v
  3199  		}
  3200  
  3201  		types.CalcSize(from)
  3202  		types.CalcSize(to)
  3203  		if from.Size() != to.Size() {
  3204  			s.Fatalf("CONVNOP width mismatch %v (%d) -> %v (%d)\n", from, from.Size(), to, to.Size())
  3205  			return nil
  3206  		}
  3207  		if etypesign(from.Kind()) != etypesign(to.Kind()) {
  3208  			s.Fatalf("CONVNOP sign mismatch %v (%s) -> %v (%s)\n", from, from.Kind(), to, to.Kind())
  3209  			return nil
  3210  		}
  3211  
  3212  		if base.Flag.Cfg.Instrumenting {
  3213  			// These appear to be fine, but they fail the
  3214  			// integer constraint below, so okay them here.
  3215  			// Sample non-integer conversion: map[string]string -> *uint8
  3216  			return v
  3217  		}
  3218  
  3219  		if etypesign(from.Kind()) == 0 {
  3220  			s.Fatalf("CONVNOP unrecognized non-integer %v -> %v\n", from, to)
  3221  			return nil
  3222  		}
  3223  
  3224  		// integer, same width, same sign
  3225  		return v
  3226  
  3227  	case ir.OCONV:
  3228  		n := n.(*ir.ConvExpr)
  3229  		x := s.expr(n.X)
  3230  		return s.conv(n, x, n.X.Type(), n.Type())
  3231  
  3232  	case ir.ODOTTYPE:
  3233  		n := n.(*ir.TypeAssertExpr)
  3234  		res, _ := s.dottype(n, false)
  3235  		return res
  3236  
  3237  	case ir.ODYNAMICDOTTYPE:
  3238  		n := n.(*ir.DynamicTypeAssertExpr)
  3239  		res, _ := s.dynamicDottype(n, false)
  3240  		return res
  3241  
  3242  	// binary ops
  3243  	case ir.OLT, ir.OEQ, ir.ONE, ir.OLE, ir.OGE, ir.OGT:
  3244  		n := n.(*ir.BinaryExpr)
  3245  		a := s.expr(n.X)
  3246  		b := s.expr(n.Y)
  3247  		if n.X.Type().IsComplex() {
  3248  			pt := types.FloatForComplex(n.X.Type())
  3249  			op := s.ssaOp(ir.OEQ, pt)
  3250  			r := s.newValueOrSfCall2(op, types.Types[types.TBOOL], s.newValue1(ssa.OpComplexReal, pt, a), s.newValue1(ssa.OpComplexReal, pt, b))
  3251  			i := s.newValueOrSfCall2(op, types.Types[types.TBOOL], s.newValue1(ssa.OpComplexImag, pt, a), s.newValue1(ssa.OpComplexImag, pt, b))
  3252  			c := s.newValue2(ssa.OpAndB, types.Types[types.TBOOL], r, i)
  3253  			switch n.Op() {
  3254  			case ir.OEQ:
  3255  				return c
  3256  			case ir.ONE:
  3257  				return s.newValue1(ssa.OpNot, types.Types[types.TBOOL], c)
  3258  			default:
  3259  				s.Fatalf("ordered complex compare %v", n.Op())
  3260  			}
  3261  		}
  3262  
  3263  		// Convert OGE and OGT into OLE and OLT.
  3264  		op := n.Op()
  3265  		switch op {
  3266  		case ir.OGE:
  3267  			op, a, b = ir.OLE, b, a
  3268  		case ir.OGT:
  3269  			op, a, b = ir.OLT, b, a
  3270  		}
  3271  		if n.X.Type().IsFloat() {
  3272  			// float comparison
  3273  			return s.newValueOrSfCall2(s.ssaOp(op, n.X.Type()), types.Types[types.TBOOL], a, b)
  3274  		}
  3275  		// integer comparison
  3276  		return s.newValue2(s.ssaOp(op, n.X.Type()), types.Types[types.TBOOL], a, b)
  3277  	case ir.OMUL:
  3278  		n := n.(*ir.BinaryExpr)
  3279  		a := s.expr(n.X)
  3280  		b := s.expr(n.Y)
  3281  		if n.Type().IsComplex() {
  3282  			mulop := ssa.OpMul64F
  3283  			addop := ssa.OpAdd64F
  3284  			subop := ssa.OpSub64F
  3285  			pt := types.FloatForComplex(n.Type()) // Could be Float32 or Float64
  3286  			wt := types.Types[types.TFLOAT64]     // Compute in Float64 to minimize cancellation error
  3287  
  3288  			areal := s.newValue1(ssa.OpComplexReal, pt, a)
  3289  			breal := s.newValue1(ssa.OpComplexReal, pt, b)
  3290  			aimag := s.newValue1(ssa.OpComplexImag, pt, a)
  3291  			bimag := s.newValue1(ssa.OpComplexImag, pt, b)
  3292  
  3293  			if pt != wt { // Widen for calculation
  3294  				areal = s.newValueOrSfCall1(ssa.OpCvt32Fto64F, wt, areal)
  3295  				breal = s.newValueOrSfCall1(ssa.OpCvt32Fto64F, wt, breal)
  3296  				aimag = s.newValueOrSfCall1(ssa.OpCvt32Fto64F, wt, aimag)
  3297  				bimag = s.newValueOrSfCall1(ssa.OpCvt32Fto64F, wt, bimag)
  3298  			}
  3299  
  3300  			xreal := s.newValueOrSfCall2(subop, wt, s.newValueOrSfCall2(mulop, wt, areal, breal), s.newValueOrSfCall2(mulop, wt, aimag, bimag))
  3301  			ximag := s.newValueOrSfCall2(addop, wt, s.newValueOrSfCall2(mulop, wt, areal, bimag), s.newValueOrSfCall2(mulop, wt, aimag, breal))
  3302  
  3303  			if pt != wt { // Narrow to store back
  3304  				xreal = s.newValueOrSfCall1(ssa.OpCvt64Fto32F, pt, xreal)
  3305  				ximag = s.newValueOrSfCall1(ssa.OpCvt64Fto32F, pt, ximag)
  3306  			}
  3307  
  3308  			return s.newValue2(ssa.OpComplexMake, n.Type(), xreal, ximag)
  3309  		}
  3310  
  3311  		if n.Type().IsFloat() {
  3312  			return s.newValueOrSfCall2(s.ssaOp(n.Op(), n.Type()), a.Type, a, b)
  3313  		}
  3314  
  3315  		return s.newValue2(s.ssaOp(n.Op(), n.Type()), a.Type, a, b)
  3316  
  3317  	case ir.ODIV:
  3318  		n := n.(*ir.BinaryExpr)
  3319  		a := s.expr(n.X)
  3320  		b := s.expr(n.Y)
  3321  		if n.Type().IsComplex() {
  3322  			// TODO this is not executed because the front-end substitutes a runtime call.
  3323  			// That probably ought to change; with modest optimization the widen/narrow
  3324  			// conversions could all be elided in larger expression trees.
  3325  			mulop := ssa.OpMul64F
  3326  			addop := ssa.OpAdd64F
  3327  			subop := ssa.OpSub64F
  3328  			divop := ssa.OpDiv64F
  3329  			pt := types.FloatForComplex(n.Type()) // Could be Float32 or Float64
  3330  			wt := types.Types[types.TFLOAT64]     // Compute in Float64 to minimize cancellation error
  3331  
  3332  			areal := s.newValue1(ssa.OpComplexReal, pt, a)
  3333  			breal := s.newValue1(ssa.OpComplexReal, pt, b)
  3334  			aimag := s.newValue1(ssa.OpComplexImag, pt, a)
  3335  			bimag := s.newValue1(ssa.OpComplexImag, pt, b)
  3336  
  3337  			if pt != wt { // Widen for calculation
  3338  				areal = s.newValueOrSfCall1(ssa.OpCvt32Fto64F, wt, areal)
  3339  				breal = s.newValueOrSfCall1(ssa.OpCvt32Fto64F, wt, breal)
  3340  				aimag = s.newValueOrSfCall1(ssa.OpCvt32Fto64F, wt, aimag)
  3341  				bimag = s.newValueOrSfCall1(ssa.OpCvt32Fto64F, wt, bimag)
  3342  			}
  3343  
  3344  			denom := s.newValueOrSfCall2(addop, wt, s.newValueOrSfCall2(mulop, wt, breal, breal), s.newValueOrSfCall2(mulop, wt, bimag, bimag))
  3345  			xreal := s.newValueOrSfCall2(addop, wt, s.newValueOrSfCall2(mulop, wt, areal, breal), s.newValueOrSfCall2(mulop, wt, aimag, bimag))
  3346  			ximag := s.newValueOrSfCall2(subop, wt, s.newValueOrSfCall2(mulop, wt, aimag, breal), s.newValueOrSfCall2(mulop, wt, areal, bimag))
  3347  
  3348  			// TODO not sure if this is best done in wide precision or narrow
  3349  			// Double-rounding might be an issue.
  3350  			// Note that the pre-SSA implementation does the entire calculation
  3351  			// in wide format, so wide is compatible.
  3352  			xreal = s.newValueOrSfCall2(divop, wt, xreal, denom)
  3353  			ximag = s.newValueOrSfCall2(divop, wt, ximag, denom)
  3354  
  3355  			if pt != wt { // Narrow to store back
  3356  				xreal = s.newValueOrSfCall1(ssa.OpCvt64Fto32F, pt, xreal)
  3357  				ximag = s.newValueOrSfCall1(ssa.OpCvt64Fto32F, pt, ximag)
  3358  			}
  3359  			return s.newValue2(ssa.OpComplexMake, n.Type(), xreal, ximag)
  3360  		}
  3361  		if n.Type().IsFloat() {
  3362  			return s.newValueOrSfCall2(s.ssaOp(n.Op(), n.Type()), a.Type, a, b)
  3363  		}
  3364  		return s.intDivide(n, a, b)
  3365  	case ir.OMOD:
  3366  		n := n.(*ir.BinaryExpr)
  3367  		a := s.expr(n.X)
  3368  		b := s.expr(n.Y)
  3369  		return s.intDivide(n, a, b)
  3370  	case ir.OADD, ir.OSUB:
  3371  		n := n.(*ir.BinaryExpr)
  3372  		a := s.expr(n.X)
  3373  		b := s.expr(n.Y)
  3374  		if n.Type().IsComplex() {
  3375  			pt := types.FloatForComplex(n.Type())
  3376  			op := s.ssaOp(n.Op(), pt)
  3377  			return s.newValue2(ssa.OpComplexMake, n.Type(),
  3378  				s.newValueOrSfCall2(op, pt, s.newValue1(ssa.OpComplexReal, pt, a), s.newValue1(ssa.OpComplexReal, pt, b)),
  3379  				s.newValueOrSfCall2(op, pt, s.newValue1(ssa.OpComplexImag, pt, a), s.newValue1(ssa.OpComplexImag, pt, b)))
  3380  		}
  3381  		if n.Type().IsFloat() {
  3382  			return s.newValueOrSfCall2(s.ssaOp(n.Op(), n.Type()), a.Type, a, b)
  3383  		}
  3384  		return s.newValue2(s.ssaOp(n.Op(), n.Type()), a.Type, a, b)
  3385  	case ir.OAND, ir.OOR, ir.OXOR:
  3386  		n := n.(*ir.BinaryExpr)
  3387  		a := s.expr(n.X)
  3388  		b := s.expr(n.Y)
  3389  		return s.newValue2(s.ssaOp(n.Op(), n.Type()), a.Type, a, b)
  3390  	case ir.OANDNOT:
  3391  		n := n.(*ir.BinaryExpr)
  3392  		a := s.expr(n.X)
  3393  		b := s.expr(n.Y)
  3394  		b = s.newValue1(s.ssaOp(ir.OBITNOT, b.Type), b.Type, b)
  3395  		return s.newValue2(s.ssaOp(ir.OAND, n.Type()), a.Type, a, b)
  3396  	case ir.OLSH, ir.ORSH:
  3397  		n := n.(*ir.BinaryExpr)
  3398  		a := s.expr(n.X)
  3399  		b := s.expr(n.Y)
  3400  		bt := b.Type
  3401  		if bt.IsSigned() {
  3402  			cmp := s.newValue2(s.ssaOp(ir.OLE, bt), types.Types[types.TBOOL], s.zeroVal(bt), b)
  3403  			s.check(cmp, ir.Syms.Panicshift)
  3404  			bt = bt.ToUnsigned()
  3405  		}
  3406  		return s.newValue2(s.ssaShiftOp(n.Op(), n.Type(), bt), a.Type, a, b)
  3407  	case ir.OANDAND, ir.OOROR:
  3408  		// To implement OANDAND (and OOROR), we introduce a
  3409  		// new temporary variable to hold the result. The
  3410  		// variable is associated with the OANDAND node in the
  3411  		// s.vars table (normally variables are only
  3412  		// associated with ONAME nodes). We convert
  3413  		//     A && B
  3414  		// to
  3415  		//     var = A
  3416  		//     if var {
  3417  		//         var = B
  3418  		//     }
  3419  		// Using var in the subsequent block introduces the
  3420  		// necessary phi variable.
  3421  		n := n.(*ir.LogicalExpr)
  3422  		el := s.expr(n.X)
  3423  		s.vars[n] = el
  3424  
  3425  		b := s.endBlock()
  3426  		b.Kind = ssa.BlockIf
  3427  		b.SetControl(el)
  3428  		// In theory, we should set b.Likely here based on context.
  3429  		// However, gc only gives us likeliness hints
  3430  		// in a single place, for plain OIF statements,
  3431  		// and passing around context is finicky, so don't bother for now.
  3432  
  3433  		bRight := s.f.NewBlock(ssa.BlockPlain)
  3434  		bResult := s.f.NewBlock(ssa.BlockPlain)
  3435  		if n.Op() == ir.OANDAND {
  3436  			b.AddEdgeTo(bRight)
  3437  			b.AddEdgeTo(bResult)
  3438  		} else if n.Op() == ir.OOROR {
  3439  			b.AddEdgeTo(bResult)
  3440  			b.AddEdgeTo(bRight)
  3441  		}
  3442  
  3443  		s.startBlock(bRight)
  3444  		er := s.expr(n.Y)
  3445  		s.vars[n] = er
  3446  
  3447  		b = s.endBlock()
  3448  		b.AddEdgeTo(bResult)
  3449  
  3450  		s.startBlock(bResult)
  3451  		return s.variable(n, types.Types[types.TBOOL])
  3452  	case ir.OCOMPLEX:
  3453  		n := n.(*ir.BinaryExpr)
  3454  		r := s.expr(n.X)
  3455  		i := s.expr(n.Y)
  3456  		return s.newValue2(ssa.OpComplexMake, n.Type(), r, i)
  3457  
  3458  	// unary ops
  3459  	case ir.ONEG:
  3460  		n := n.(*ir.UnaryExpr)
  3461  		a := s.expr(n.X)
  3462  		if n.Type().IsComplex() {
  3463  			tp := types.FloatForComplex(n.Type())
  3464  			negop := s.ssaOp(n.Op(), tp)
  3465  			return s.newValue2(ssa.OpComplexMake, n.Type(),
  3466  				s.newValue1(negop, tp, s.newValue1(ssa.OpComplexReal, tp, a)),
  3467  				s.newValue1(negop, tp, s.newValue1(ssa.OpComplexImag, tp, a)))
  3468  		}
  3469  		return s.newValue1(s.ssaOp(n.Op(), n.Type()), a.Type, a)
  3470  	case ir.ONOT, ir.OBITNOT:
  3471  		n := n.(*ir.UnaryExpr)
  3472  		a := s.expr(n.X)
  3473  		return s.newValue1(s.ssaOp(n.Op(), n.Type()), a.Type, a)
  3474  	case ir.OIMAG, ir.OREAL:
  3475  		n := n.(*ir.UnaryExpr)
  3476  		a := s.expr(n.X)
  3477  		return s.newValue1(s.ssaOp(n.Op(), n.X.Type()), n.Type(), a)
  3478  	case ir.OPLUS:
  3479  		n := n.(*ir.UnaryExpr)
  3480  		return s.expr(n.X)
  3481  
  3482  	case ir.OADDR:
  3483  		n := n.(*ir.AddrExpr)
  3484  		return s.addr(n.X)
  3485  
  3486  	case ir.ORESULT:
  3487  		n := n.(*ir.ResultExpr)
  3488  		if s.prevCall == nil || s.prevCall.Op != ssa.OpStaticLECall && s.prevCall.Op != ssa.OpInterLECall && s.prevCall.Op != ssa.OpClosureLECall {
  3489  			panic("Expected to see a previous call")
  3490  		}
  3491  		which := n.Index
  3492  		if which == -1 {
  3493  			panic(fmt.Errorf("ORESULT %v does not match call %s", n, s.prevCall))
  3494  		}
  3495  		return s.resultOfCall(s.prevCall, which, n.Type())
  3496  
  3497  	case ir.ODEREF:
  3498  		n := n.(*ir.StarExpr)
  3499  		p := s.exprPtr(n.X, n.Bounded(), n.Pos())
  3500  		return s.load(n.Type(), p)
  3501  
  3502  	case ir.ODOT:
  3503  		n := n.(*ir.SelectorExpr)
  3504  		if n.X.Op() == ir.OSTRUCTLIT {
  3505  			// All literals with nonzero fields have already been
  3506  			// rewritten during walk. Any that remain are just T{}
  3507  			// or equivalents. Use the zero value.
  3508  			if !ir.IsZero(n.X) {
  3509  				s.Fatalf("literal with nonzero value in SSA: %v", n.X)
  3510  			}
  3511  			return s.zeroVal(n.Type())
  3512  		}
  3513  		// If n is addressable and can't be represented in
  3514  		// SSA, then load just the selected field. This
  3515  		// prevents false memory dependencies in race/msan/asan
  3516  		// instrumentation.
  3517  		if ir.IsAddressable(n) && !s.canSSA(n) {
  3518  			p := s.addr(n)
  3519  			return s.load(n.Type(), p)
  3520  		}
  3521  		v := s.expr(n.X)
  3522  		return s.newValue1I(ssa.OpStructSelect, n.Type(), int64(fieldIdx(n)), v)
  3523  
  3524  	case ir.ODOTPTR:
  3525  		n := n.(*ir.SelectorExpr)
  3526  		p := s.exprPtr(n.X, n.Bounded(), n.Pos())
  3527  		p = s.newValue1I(ssa.OpOffPtr, types.NewPtr(n.Type()), n.Offset(), p)
  3528  		return s.load(n.Type(), p)
  3529  
  3530  	case ir.OINDEX:
  3531  		n := n.(*ir.IndexExpr)
  3532  		switch {
  3533  		case n.X.Type().IsString():
  3534  			if n.Bounded() && ir.IsConst(n.X, constant.String) && ir.IsConst(n.Index, constant.Int) {
  3535  				// Replace "abc"[1] with 'b'.
  3536  				// Delayed until now because "abc"[1] is not an ideal constant.
  3537  				// See test/fixedbugs/issue11370.go.
  3538  				return s.newValue0I(ssa.OpConst8, types.Types[types.TUINT8], int64(int8(ir.StringVal(n.X)[ir.Int64Val(n.Index)])))
  3539  			}
  3540  			a := s.expr(n.X)
  3541  			i := s.expr(n.Index)
  3542  			len := s.newValue1(ssa.OpStringLen, types.Types[types.TINT], a)
  3543  			i = s.boundsCheck(i, len, ssa.BoundsIndex, n.Bounded())
  3544  			ptrtyp := s.f.Config.Types.BytePtr
  3545  			ptr := s.newValue1(ssa.OpStringPtr, ptrtyp, a)
  3546  			if ir.IsConst(n.Index, constant.Int) {
  3547  				ptr = s.newValue1I(ssa.OpOffPtr, ptrtyp, ir.Int64Val(n.Index), ptr)
  3548  			} else {
  3549  				ptr = s.newValue2(ssa.OpAddPtr, ptrtyp, ptr, i)
  3550  			}
  3551  			return s.load(types.Types[types.TUINT8], ptr)
  3552  		case n.X.Type().IsSlice():
  3553  			p := s.addr(n)
  3554  			return s.load(n.X.Type().Elem(), p)
  3555  		case n.X.Type().IsArray():
  3556  			if ssa.CanSSA(n.X.Type()) {
  3557  				// SSA can handle arrays of length at most 1.
  3558  				bound := n.X.Type().NumElem()
  3559  				a := s.expr(n.X)
  3560  				i := s.expr(n.Index)
  3561  				if bound == 0 {
  3562  					// Bounds check will never succeed.  Might as well
  3563  					// use constants for the bounds check.
  3564  					z := s.constInt(types.Types[types.TINT], 0)
  3565  					s.boundsCheck(z, z, ssa.BoundsIndex, false)
  3566  					// The return value won't be live. In case bounds checks
  3567  					// are turned off, load from (*T)(nil) to cause a segfault.
  3568  					return s.load(n.Type(), s.constNil(n.Type().PtrTo()))
  3569  				}
  3570  				len := s.constInt(types.Types[types.TINT], bound)
  3571  				s.boundsCheck(i, len, ssa.BoundsIndex, n.Bounded()) // checks i == 0
  3572  				return s.newValue1I(ssa.OpArraySelect, n.Type(), 0, a)
  3573  			}
  3574  			p := s.addr(n)
  3575  			return s.load(n.X.Type().Elem(), p)
  3576  		default:
  3577  			s.Fatalf("bad type for index %v", n.X.Type())
  3578  			return nil
  3579  		}
  3580  
  3581  	case ir.OLEN, ir.OCAP:
  3582  		n := n.(*ir.UnaryExpr)
  3583  		// Note: all constant cases are handled by the frontend. If len or cap
  3584  		// makes it here, we want the side effects of the argument. See issue 72844.
  3585  		a := s.expr(n.X)
  3586  		t := n.X.Type()
  3587  		switch {
  3588  		case t.IsSlice():
  3589  			op := ssa.OpSliceLen
  3590  			if n.Op() == ir.OCAP {
  3591  				op = ssa.OpSliceCap
  3592  			}
  3593  			return s.newValue1(op, types.Types[types.TINT], a)
  3594  		case t.IsString(): // string; not reachable for OCAP
  3595  			return s.newValue1(ssa.OpStringLen, types.Types[types.TINT], a)
  3596  		case t.IsMap(), t.IsChan():
  3597  			return s.referenceTypeBuiltin(n, a)
  3598  		case t.IsArray():
  3599  			return s.constInt(types.Types[types.TINT], t.NumElem())
  3600  		case t.IsPtr() && t.Elem().IsArray():
  3601  			return s.constInt(types.Types[types.TINT], t.Elem().NumElem())
  3602  		default:
  3603  			s.Fatalf("bad type in len/cap: %v", t)
  3604  			return nil
  3605  		}
  3606  
  3607  	case ir.OSPTR:
  3608  		n := n.(*ir.UnaryExpr)
  3609  		a := s.expr(n.X)
  3610  		if n.X.Type().IsSlice() {
  3611  			if n.Bounded() {
  3612  				return s.newValue1(ssa.OpSlicePtr, n.Type(), a)
  3613  			}
  3614  			return s.newValue1(ssa.OpSlicePtrUnchecked, n.Type(), a)
  3615  		} else {
  3616  			return s.newValue1(ssa.OpStringPtr, n.Type(), a)
  3617  		}
  3618  
  3619  	case ir.OITAB:
  3620  		n := n.(*ir.UnaryExpr)
  3621  		a := s.expr(n.X)
  3622  		return s.newValue1(ssa.OpITab, n.Type(), a)
  3623  
  3624  	case ir.OIDATA:
  3625  		n := n.(*ir.UnaryExpr)
  3626  		a := s.expr(n.X)
  3627  		return s.newValue1(ssa.OpIData, n.Type(), a)
  3628  
  3629  	case ir.OMAKEFACE:
  3630  		n := n.(*ir.BinaryExpr)
  3631  		tab := s.expr(n.X)
  3632  		data := s.expr(n.Y)
  3633  		return s.newValue2(ssa.OpIMake, n.Type(), tab, data)
  3634  
  3635  	case ir.OSLICEHEADER:
  3636  		n := n.(*ir.SliceHeaderExpr)
  3637  		p := s.expr(n.Ptr)
  3638  		l := s.expr(n.Len)
  3639  		c := s.expr(n.Cap)
  3640  		return s.newValue3(ssa.OpSliceMake, n.Type(), p, l, c)
  3641  
  3642  	case ir.OSTRINGHEADER:
  3643  		n := n.(*ir.StringHeaderExpr)
  3644  		p := s.expr(n.Ptr)
  3645  		l := s.expr(n.Len)
  3646  		return s.newValue2(ssa.OpStringMake, n.Type(), p, l)
  3647  
  3648  	case ir.OSLICE, ir.OSLICEARR, ir.OSLICE3, ir.OSLICE3ARR:
  3649  		n := n.(*ir.SliceExpr)
  3650  		check := s.checkPtrEnabled && n.Op() == ir.OSLICE3ARR && n.X.Op() == ir.OCONVNOP && n.X.(*ir.ConvExpr).X.Type().IsUnsafePtr()
  3651  		v := s.exprCheckPtr(n.X, !check)
  3652  		var i, j, k *ssa.Value
  3653  		if n.Low != nil {
  3654  			i = s.expr(n.Low)
  3655  		}
  3656  		if n.High != nil {
  3657  			j = s.expr(n.High)
  3658  		}
  3659  		if n.Max != nil {
  3660  			k = s.expr(n.Max)
  3661  		}
  3662  		p, l, c := s.slice(v, i, j, k, n.Bounded())
  3663  		if check {
  3664  			// Emit checkptr instrumentation after bound check to prevent false positive, see #46938.
  3665  			s.checkPtrAlignment(n.X.(*ir.ConvExpr), v, s.conv(n.Max, k, k.Type, types.Types[types.TUINTPTR]))
  3666  		}
  3667  		return s.newValue3(ssa.OpSliceMake, n.Type(), p, l, c)
  3668  
  3669  	case ir.OSLICESTR:
  3670  		n := n.(*ir.SliceExpr)
  3671  		v := s.expr(n.X)
  3672  		var i, j *ssa.Value
  3673  		if n.Low != nil {
  3674  			i = s.expr(n.Low)
  3675  		}
  3676  		if n.High != nil {
  3677  			j = s.expr(n.High)
  3678  		}
  3679  		p, l, _ := s.slice(v, i, j, nil, n.Bounded())
  3680  		return s.newValue2(ssa.OpStringMake, n.Type(), p, l)
  3681  
  3682  	case ir.OSLICE2ARRPTR:
  3683  		// if arrlen > slice.len {
  3684  		//   panic(...)
  3685  		// }
  3686  		// slice.ptr
  3687  		n := n.(*ir.ConvExpr)
  3688  		v := s.expr(n.X)
  3689  		nelem := n.Type().Elem().NumElem()
  3690  		arrlen := s.constInt(types.Types[types.TINT], nelem)
  3691  		cap := s.newValue1(ssa.OpSliceLen, types.Types[types.TINT], v)
  3692  		s.boundsCheck(arrlen, cap, ssa.BoundsConvert, false)
  3693  		op := ssa.OpSlicePtr
  3694  		if nelem == 0 {
  3695  			op = ssa.OpSlicePtrUnchecked
  3696  		}
  3697  		return s.newValue1(op, n.Type(), v)
  3698  
  3699  	case ir.OCALLFUNC:
  3700  		n := n.(*ir.CallExpr)
  3701  		if ir.IsIntrinsicCall(n) {
  3702  			return s.intrinsicCall(n)
  3703  		}
  3704  		fallthrough
  3705  
  3706  	case ir.OCALLINTER:
  3707  		n := n.(*ir.CallExpr)
  3708  		return s.callResult(n, callNormal)
  3709  
  3710  	case ir.OGETG:
  3711  		n := n.(*ir.CallExpr)
  3712  		return s.newValue1(ssa.OpGetG, n.Type(), s.mem())
  3713  
  3714  	case ir.OGETCALLERSP:
  3715  		n := n.(*ir.CallExpr)
  3716  		return s.newValue1(ssa.OpGetCallerSP, n.Type(), s.mem())
  3717  
  3718  	case ir.OAPPEND:
  3719  		return s.append(n.(*ir.CallExpr), false)
  3720  
  3721  	case ir.OMOVE2HEAP:
  3722  		return s.move2heap(n.(*ir.MoveToHeapExpr))
  3723  
  3724  	case ir.OMIN, ir.OMAX:
  3725  		return s.minMax(n.(*ir.CallExpr))
  3726  
  3727  	case ir.OSTRUCTLIT, ir.OARRAYLIT:
  3728  		// All literals with nonzero fields have already been
  3729  		// rewritten during walk. Any that remain are just T{}
  3730  		// or equivalents. Use the zero value.
  3731  		n := n.(*ir.CompLitExpr)
  3732  		if !ir.IsZero(n) {
  3733  			s.Fatalf("literal with nonzero value in SSA: %v", n)
  3734  		}
  3735  		return s.zeroVal(n.Type())
  3736  
  3737  	case ir.ONEW:
  3738  		n := n.(*ir.UnaryExpr)
  3739  		if x, ok := n.X.(*ir.DynamicType); ok && x.Op() == ir.ODYNAMICTYPE {
  3740  			return s.newObjectNonSpecialized(n.Type().Elem(), s.expr(x.RType))
  3741  		}
  3742  		return s.newObject(n.Type().Elem())
  3743  
  3744  	case ir.OUNSAFEADD:
  3745  		n := n.(*ir.BinaryExpr)
  3746  		ptr := s.expr(n.X)
  3747  		len := s.expr(n.Y)
  3748  
  3749  		// Force len to uintptr to prevent misuse of garbage bits in the
  3750  		// upper part of the register (#48536).
  3751  		len = s.conv(n, len, len.Type, types.Types[types.TUINTPTR])
  3752  
  3753  		return s.newValue2(ssa.OpAddPtr, n.Type(), ptr, len)
  3754  
  3755  	default:
  3756  		s.Fatalf("unhandled expr %v", n.Op())
  3757  		return nil
  3758  	}
  3759  }
  3760  
  3761  func (s *state) resultOfCall(c *ssa.Value, which int64, t *types.Type) *ssa.Value {
  3762  	aux := c.Aux.(*ssa.AuxCall)
  3763  	pa := aux.ParamAssignmentForResult(which)
  3764  	// TODO(register args) determine if in-memory TypeOK is better loaded early from SelectNAddr or later when SelectN is expanded.
  3765  	// SelectN is better for pattern-matching and possible call-aware analysis we might want to do in the future.
  3766  	if len(pa.Registers) == 0 && !ssa.CanSSA(t) {
  3767  		addr := s.newValue1I(ssa.OpSelectNAddr, types.NewPtr(t), which, c)
  3768  		return s.rawLoad(t, addr)
  3769  	}
  3770  	return s.newValue1I(ssa.OpSelectN, t, which, c)
  3771  }
  3772  
  3773  func (s *state) resultAddrOfCall(c *ssa.Value, which int64, t *types.Type) *ssa.Value {
  3774  	aux := c.Aux.(*ssa.AuxCall)
  3775  	pa := aux.ParamAssignmentForResult(which)
  3776  	if len(pa.Registers) == 0 {
  3777  		return s.newValue1I(ssa.OpSelectNAddr, types.NewPtr(t), which, c)
  3778  	}
  3779  	_, addr := s.temp(c.Pos, t)
  3780  	rval := s.newValue1I(ssa.OpSelectN, t, which, c)
  3781  	s.vars[memVar] = s.newValue3Apos(ssa.OpStore, types.TypeMem, t, addr, rval, s.mem(), false)
  3782  	return addr
  3783  }
  3784  
  3785  // Get backing store information for an append call.
  3786  func (s *state) getBackingStoreInfoForAppend(n *ir.CallExpr) *backingStoreInfo {
  3787  	if n.Esc() != ir.EscNone {
  3788  		return nil
  3789  	}
  3790  	return s.getBackingStoreInfo(n.Args[0])
  3791  }
  3792  func (s *state) getBackingStoreInfo(n ir.Node) *backingStoreInfo {
  3793  	t := n.Type()
  3794  	et := t.Elem()
  3795  	maxStackSize := int64(base.Debug.VariableMakeThreshold)
  3796  	if et.Size() == 0 || et.Size() > maxStackSize {
  3797  		return nil
  3798  	}
  3799  	if base.Flag.N != 0 {
  3800  		return nil
  3801  	}
  3802  	if !base.VariableMakeHash.MatchPos(n.Pos(), nil) {
  3803  		return nil
  3804  	}
  3805  	i := s.backingStores[n]
  3806  	if i != nil {
  3807  		return i
  3808  	}
  3809  
  3810  	// Build type of backing store.
  3811  	K := maxStackSize / et.Size() // rounds down
  3812  	KT := types.NewArray(et, K)
  3813  	KT.SetNoalg(true)
  3814  	types.CalcArraySize(KT)
  3815  	// Align more than naturally for the type KT. See issue 73199.
  3816  	align := types.NewArray(types.Types[types.TUINTPTR], 0)
  3817  	types.CalcArraySize(align)
  3818  	storeTyp := types.NewStruct([]*types.Field{
  3819  		{Sym: types.BlankSym, Type: align},
  3820  		{Sym: types.BlankSym, Type: KT},
  3821  	})
  3822  	storeTyp.SetNoalg(true)
  3823  	types.CalcStructSize(storeTyp)
  3824  
  3825  	// Make backing store variable.
  3826  	backingStore := typecheck.TempAt(n.Pos(), s.curfn, storeTyp)
  3827  	backingStore.SetAddrtaken(true)
  3828  
  3829  	// Make "used" boolean.
  3830  	used := typecheck.TempAt(n.Pos(), s.curfn, types.Types[types.TBOOL])
  3831  	if s.curBlock == s.f.Entry {
  3832  		s.vars[used] = s.constBool(false)
  3833  	} else {
  3834  		// initialize this variable at end of entry block
  3835  		s.defvars[s.f.Entry.ID][used] = s.constBool(false)
  3836  	}
  3837  
  3838  	// Initialize an info structure.
  3839  	if s.backingStores == nil {
  3840  		s.backingStores = map[ir.Node]*backingStoreInfo{}
  3841  	}
  3842  	i = &backingStoreInfo{K: K, store: backingStore, used: used, usedStatic: false}
  3843  	s.backingStores[n] = i
  3844  	return i
  3845  }
  3846  
  3847  // append converts an OAPPEND node to SSA.
  3848  // If inplace is false, it converts the OAPPEND expression n to an ssa.Value,
  3849  // adds it to s, and returns the Value.
  3850  // If inplace is true, it writes the result of the OAPPEND expression n
  3851  // back to the slice being appended to, and returns nil.
  3852  // inplace MUST be set to false if the slice can be SSA'd.
  3853  // Note: this code only handles fixed-count appends. Dotdotdot appends
  3854  // have already been rewritten at this point (by walk).
  3855  func (s *state) append(n *ir.CallExpr, inplace bool) *ssa.Value {
  3856  	// If inplace is false, process as expression "append(s, e1, e2, e3)":
  3857  	//
  3858  	// ptr, len, cap := s
  3859  	// len += 3
  3860  	// if uint(len) > uint(cap) {
  3861  	//     ptr, len, cap = growslice(ptr, len, cap, 3, typ)
  3862  	//     Note that len is unmodified by growslice.
  3863  	// }
  3864  	// // with write barriers, if needed:
  3865  	// *(ptr+(len-3)) = e1
  3866  	// *(ptr+(len-2)) = e2
  3867  	// *(ptr+(len-1)) = e3
  3868  	// return makeslice(ptr, len, cap)
  3869  	//
  3870  	//
  3871  	// If inplace is true, process as statement "s = append(s, e1, e2, e3)":
  3872  	//
  3873  	// a := &s
  3874  	// ptr, len, cap := s
  3875  	// len += 3
  3876  	// if uint(len) > uint(cap) {
  3877  	//    ptr, len, cap = growslice(ptr, len, cap, 3, typ)
  3878  	//    vardef(a)    // if necessary, advise liveness we are writing a new a
  3879  	//    *a.cap = cap // write before ptr to avoid a spill
  3880  	//    *a.ptr = ptr // with write barrier
  3881  	// }
  3882  	// *a.len = len
  3883  	// // with write barriers, if needed:
  3884  	// *(ptr+(len-3)) = e1
  3885  	// *(ptr+(len-2)) = e2
  3886  	// *(ptr+(len-1)) = e3
  3887  
  3888  	et := n.Type().Elem()
  3889  	pt := types.NewPtr(et)
  3890  
  3891  	// Evaluate slice
  3892  	sn := n.Args[0] // the slice node is the first in the list
  3893  	var slice, addr *ssa.Value
  3894  	if inplace {
  3895  		addr = s.addr(sn)
  3896  		slice = s.load(n.Type(), addr)
  3897  	} else {
  3898  		slice = s.expr(sn)
  3899  	}
  3900  
  3901  	// Allocate new blocks
  3902  	grow := s.f.NewBlock(ssa.BlockPlain)
  3903  	assign := s.f.NewBlock(ssa.BlockPlain)
  3904  
  3905  	// Decomposse input slice.
  3906  	p := s.newValue1(ssa.OpSlicePtr, pt, slice)
  3907  	l := s.newValue1(ssa.OpSliceLen, types.Types[types.TINT], slice)
  3908  	c := s.newValue1(ssa.OpSliceCap, types.Types[types.TINT], slice)
  3909  
  3910  	// Add number of new elements to length.
  3911  	nargs := s.constInt(types.Types[types.TINT], int64(len(n.Args)-1))
  3912  	oldLen := l
  3913  	l = s.newValue2(s.ssaOp(ir.OADD, types.Types[types.TINT]), types.Types[types.TINT], l, nargs)
  3914  
  3915  	// Decide if we need to grow
  3916  	cmp := s.newValue2(s.ssaOp(ir.OLT, types.Types[types.TUINT]), types.Types[types.TBOOL], c, l)
  3917  
  3918  	// Record values of ptr/len/cap before branch.
  3919  	s.vars[ptrVar] = p
  3920  	s.vars[lenVar] = l
  3921  	if !inplace {
  3922  		s.vars[capVar] = c
  3923  	}
  3924  
  3925  	b := s.endBlock()
  3926  	b.Kind = ssa.BlockIf
  3927  	b.Likely = ssa.BranchUnlikely
  3928  	b.SetControl(cmp)
  3929  	b.AddEdgeTo(grow)
  3930  	b.AddEdgeTo(assign)
  3931  
  3932  	// If the result of the append does not escape, we can use
  3933  	// a stack-allocated backing store if len is small enough.
  3934  	// A stack-allocated backing store could be used at every
  3935  	// append that qualifies, but we limit it in some cases to
  3936  	// avoid wasted code and stack space.
  3937  	//
  3938  	// Note that we have two different strategies.
  3939  	// 1. The standard strategy is just to allocate the full
  3940  	//    backing store at the first append.
  3941  	// 2. An alternate strategy is used when
  3942  	//        a. The backing store eventually escapes via move2heap
  3943  	//    and b. The capacity is used somehow
  3944  	//    In this case, we don't want to just allocate
  3945  	//    the full buffer at the first append, because when
  3946  	//    we move2heap the buffer to the heap when it escapes,
  3947  	//    we might end up wasting memory because we can't
  3948  	//    change the capacity.
  3949  	//    So in this case we use growsliceBuf to reuse the buffer
  3950  	//    and walk one step up the size class ladder each time.
  3951  	//
  3952  	// TODO: handle ... append case? Currently we handle only
  3953  	// a fixed number of appended elements.
  3954  	var info *backingStoreInfo
  3955  	if !inplace {
  3956  		info = s.getBackingStoreInfoForAppend(n)
  3957  	}
  3958  
  3959  	if !inplace && info != nil && !n.UseBuf && !info.usedStatic {
  3960  		// if l <= K {
  3961  		//   if !used {
  3962  		//     if oldLen == 0 {
  3963  		//       var store [K]T
  3964  		//       s = store[:l:K]
  3965  		//       used = true
  3966  		//     }
  3967  		//   }
  3968  		// }
  3969  		// ... if we didn't use the stack backing store, call growslice ...
  3970  		//
  3971  		// oldLen==0 is not strictly necessary, but requiring it means
  3972  		// we don't have to worry about copying existing elements.
  3973  		// Allowing oldLen>0 would add complication. Worth it? I would guess not.
  3974  		//
  3975  		// TODO: instead of the used boolean, we could insist that this only applies
  3976  		// to monotonic slices, those which once they have >0 entries never go back
  3977  		// to 0 entries. Then oldLen==0 is enough.
  3978  		//
  3979  		// We also do this for append(x, ...) once for every x.
  3980  		// It is ok to do it more often, but it is probably helpful only for
  3981  		// the first instance. TODO: this could use more tuning. Using ir.Node
  3982  		// as the key works for *ir.Name instances but probably nothing else.
  3983  		info.usedStatic = true
  3984  		// TODO: unset usedStatic somehow?
  3985  
  3986  		usedTestBlock := s.f.NewBlock(ssa.BlockPlain)
  3987  		oldLenTestBlock := s.f.NewBlock(ssa.BlockPlain)
  3988  		bodyBlock := s.f.NewBlock(ssa.BlockPlain)
  3989  		growSlice := s.f.NewBlock(ssa.BlockPlain)
  3990  		tInt := types.Types[types.TINT]
  3991  		tBool := types.Types[types.TBOOL]
  3992  
  3993  		// if l <= K
  3994  		s.startBlock(grow)
  3995  		kTest := s.newValue2(s.ssaOp(ir.OLE, tInt), tBool, l, s.constInt(tInt, info.K))
  3996  		b := s.endBlock()
  3997  		b.Kind = ssa.BlockIf
  3998  		b.SetControl(kTest)
  3999  		b.AddEdgeTo(usedTestBlock)
  4000  		b.AddEdgeTo(growSlice)
  4001  		b.Likely = ssa.BranchLikely
  4002  
  4003  		// if !used
  4004  		s.startBlock(usedTestBlock)
  4005  		usedTest := s.newValue1(ssa.OpNot, tBool, s.expr(info.used))
  4006  		b = s.endBlock()
  4007  		b.Kind = ssa.BlockIf
  4008  		b.SetControl(usedTest)
  4009  		b.AddEdgeTo(oldLenTestBlock)
  4010  		b.AddEdgeTo(growSlice)
  4011  		b.Likely = ssa.BranchLikely
  4012  
  4013  		// if oldLen == 0
  4014  		s.startBlock(oldLenTestBlock)
  4015  		oldLenTest := s.newValue2(s.ssaOp(ir.OEQ, tInt), tBool, oldLen, s.constInt(tInt, 0))
  4016  		b = s.endBlock()
  4017  		b.Kind = ssa.BlockIf
  4018  		b.SetControl(oldLenTest)
  4019  		b.AddEdgeTo(bodyBlock)
  4020  		b.AddEdgeTo(growSlice)
  4021  		b.Likely = ssa.BranchLikely
  4022  
  4023  		// var store struct { _ [0]uintptr; arr [K]T }
  4024  		s.startBlock(bodyBlock)
  4025  		if et.HasPointers() {
  4026  			s.vars[memVar] = s.newValue1A(ssa.OpVarDef, types.TypeMem, info.store, s.mem())
  4027  		}
  4028  		addr := s.addr(info.store)
  4029  		s.zero(info.store.Type(), addr)
  4030  
  4031  		// s = store.arr[:l:K]
  4032  		s.vars[ptrVar] = addr
  4033  		s.vars[lenVar] = l // nargs would also be ok because of the oldLen==0 test.
  4034  		s.vars[capVar] = s.constInt(tInt, info.K)
  4035  
  4036  		// used = true
  4037  		s.assign(info.used, s.constBool(true), false, 0)
  4038  		b = s.endBlock()
  4039  		b.AddEdgeTo(assign)
  4040  
  4041  		// New block to use for growslice call.
  4042  		grow = growSlice
  4043  	}
  4044  
  4045  	// Call growslice
  4046  	s.startBlock(grow)
  4047  	taddr := s.expr(n.Fun)
  4048  	var r []*ssa.Value
  4049  	if info != nil && n.UseBuf {
  4050  		// Use stack-allocated buffer as backing store, if we can.
  4051  		if et.HasPointers() && !info.usedStatic {
  4052  			// Initialize in the function header. Not the best place,
  4053  			// but it makes sure we don't scan this area before it is
  4054  			// initialized.
  4055  			mem := s.defvars[s.f.Entry.ID][memVar]
  4056  			mem = s.f.Entry.NewValue1A(n.Pos(), ssa.OpVarDef, types.TypeMem, info.store, mem)
  4057  			addr := s.f.Entry.NewValue2A(n.Pos(), ssa.OpLocalAddr, types.NewPtr(info.store.Type()), info.store, s.sp, mem)
  4058  			mem = s.f.Entry.NewValue2I(n.Pos(), ssa.OpZero, types.TypeMem, info.store.Type().Size(), addr, mem)
  4059  			mem.Aux = info.store.Type()
  4060  			s.defvars[s.f.Entry.ID][memVar] = mem
  4061  			info.usedStatic = true
  4062  		}
  4063  		fn := ir.Syms.GrowsliceBuf
  4064  		if goexperiment.RuntimeFreegc && n.AppendNoAlias && !et.HasPointers() {
  4065  			// The append is for a non-aliased slice where the runtime knows how to free
  4066  			// the old logically dead backing store after growth.
  4067  			// TODO(thepudds): for now, we only use the NoAlias version for element types
  4068  			// without pointers while waiting on additional runtime support (CL 698515).
  4069  			fn = ir.Syms.GrowsliceBufNoAlias
  4070  		}
  4071  		r = s.rtcall(fn, true, []*types.Type{n.Type()}, p, l, c, nargs, taddr, s.addr(info.store), s.constInt(types.Types[types.TINT], info.K))
  4072  	} else {
  4073  		fn := ir.Syms.Growslice
  4074  		if goexperiment.RuntimeFreegc && n.AppendNoAlias && !et.HasPointers() {
  4075  			// The append is for a non-aliased slice where the runtime knows how to free
  4076  			// the old logically dead backing store after growth.
  4077  			// TODO(thepudds): for now, we only use the NoAlias version for element types
  4078  			// without pointers while waiting on additional runtime support (CL 698515).
  4079  			fn = ir.Syms.GrowsliceNoAlias
  4080  		}
  4081  		r = s.rtcall(fn, true, []*types.Type{n.Type()}, p, l, c, nargs, taddr)
  4082  	}
  4083  
  4084  	// Decompose output slice
  4085  	p = s.newValue1(ssa.OpSlicePtr, pt, r[0])
  4086  	l = s.newValue1(ssa.OpSliceLen, types.Types[types.TINT], r[0])
  4087  	c = s.newValue1(ssa.OpSliceCap, types.Types[types.TINT], r[0])
  4088  
  4089  	s.vars[ptrVar] = p
  4090  	s.vars[lenVar] = l
  4091  	s.vars[capVar] = c
  4092  	if inplace {
  4093  		if sn.Op() == ir.ONAME {
  4094  			sn := sn.(*ir.Name)
  4095  			if sn.Class != ir.PEXTERN {
  4096  				// Tell liveness we're about to build a new slice
  4097  				s.vars[memVar] = s.newValue1A(ssa.OpVarDef, types.TypeMem, sn, s.mem())
  4098  			}
  4099  		}
  4100  		capaddr := s.newValue1I(ssa.OpOffPtr, s.f.Config.Types.IntPtr, types.SliceCapOffset, addr)
  4101  		s.store(types.Types[types.TINT], capaddr, c)
  4102  		s.store(pt, addr, p)
  4103  	}
  4104  
  4105  	b = s.endBlock()
  4106  	b.AddEdgeTo(assign)
  4107  
  4108  	// assign new elements to slots
  4109  	s.startBlock(assign)
  4110  	p = s.variable(ptrVar, pt)                      // generates phi for ptr
  4111  	l = s.variable(lenVar, types.Types[types.TINT]) // generates phi for len
  4112  	if !inplace {
  4113  		c = s.variable(capVar, types.Types[types.TINT]) // generates phi for cap
  4114  	}
  4115  
  4116  	if inplace {
  4117  		// Update length in place.
  4118  		// We have to wait until here to make sure growslice succeeded.
  4119  		lenaddr := s.newValue1I(ssa.OpOffPtr, s.f.Config.Types.IntPtr, types.SliceLenOffset, addr)
  4120  		s.store(types.Types[types.TINT], lenaddr, l)
  4121  	}
  4122  
  4123  	// Evaluate args
  4124  	type argRec struct {
  4125  		// if store is true, we're appending the value v.  If false, we're appending the
  4126  		// value at *v.
  4127  		v     *ssa.Value
  4128  		store bool
  4129  	}
  4130  	args := make([]argRec, 0, len(n.Args[1:]))
  4131  	for _, n := range n.Args[1:] {
  4132  		if ssa.CanSSA(n.Type()) {
  4133  			args = append(args, argRec{v: s.expr(n), store: true})
  4134  		} else {
  4135  			v := s.addr(n)
  4136  			args = append(args, argRec{v: v})
  4137  		}
  4138  	}
  4139  
  4140  	// Write args into slice.
  4141  	oldLen = s.newValue2(s.ssaOp(ir.OSUB, types.Types[types.TINT]), types.Types[types.TINT], l, nargs)
  4142  	p2 := s.newValue2(ssa.OpPtrIndex, pt, p, oldLen)
  4143  	for i, arg := range args {
  4144  		addr := s.newValue2(ssa.OpPtrIndex, pt, p2, s.constInt(types.Types[types.TINT], int64(i)))
  4145  		if arg.store {
  4146  			s.storeType(et, addr, arg.v, 0, true)
  4147  		} else {
  4148  			s.move(et, addr, arg.v)
  4149  		}
  4150  	}
  4151  
  4152  	// The following deletions have no practical effect at this time
  4153  	// because state.vars has been reset by the preceding state.startBlock.
  4154  	// They only enforce the fact that these variables are no longer need in
  4155  	// the current scope.
  4156  	delete(s.vars, ptrVar)
  4157  	delete(s.vars, lenVar)
  4158  	if !inplace {
  4159  		delete(s.vars, capVar)
  4160  	}
  4161  
  4162  	// make result
  4163  	if inplace {
  4164  		return nil
  4165  	}
  4166  	return s.newValue3(ssa.OpSliceMake, n.Type(), p, l, c)
  4167  }
  4168  
  4169  func (s *state) move2heap(n *ir.MoveToHeapExpr) *ssa.Value {
  4170  	// s := n.Slice
  4171  	// if s.ptr points to current stack frame {
  4172  	//     s2 := make([]T, s.len, s.cap)
  4173  	//     copy(s2[:cap], s[:cap])
  4174  	//     s = s2
  4175  	// }
  4176  	// return s
  4177  
  4178  	slice := s.expr(n.Slice)
  4179  	et := slice.Type.Elem()
  4180  	pt := types.NewPtr(et)
  4181  
  4182  	info := s.getBackingStoreInfo(n)
  4183  	if info == nil {
  4184  		// Backing store will never be stack allocated, so
  4185  		// move2heap is a no-op.
  4186  		return slice
  4187  	}
  4188  
  4189  	// Decomposse input slice.
  4190  	p := s.newValue1(ssa.OpSlicePtr, pt, slice)
  4191  	l := s.newValue1(ssa.OpSliceLen, types.Types[types.TINT], slice)
  4192  	c := s.newValue1(ssa.OpSliceCap, types.Types[types.TINT], slice)
  4193  
  4194  	moveBlock := s.f.NewBlock(ssa.BlockPlain)
  4195  	mergeBlock := s.f.NewBlock(ssa.BlockPlain)
  4196  
  4197  	s.vars[ptrVar] = p
  4198  	s.vars[lenVar] = l
  4199  	s.vars[capVar] = c
  4200  
  4201  	// Decide if we need to move the slice backing store.
  4202  	// It needs to be moved if it is currently on the stack.
  4203  	sub := ssa.OpSub64
  4204  	less := ssa.OpLess64U
  4205  	if s.config.PtrSize == 4 {
  4206  		sub = ssa.OpSub32
  4207  		less = ssa.OpLess32U
  4208  	}
  4209  	callerSP := s.newValue1(ssa.OpGetCallerSP, types.Types[types.TUINTPTR], s.mem())
  4210  	frameSize := s.newValue2(sub, types.Types[types.TUINTPTR], callerSP, s.sp)
  4211  	pInt := s.newValue2(ssa.OpConvert, types.Types[types.TUINTPTR], p, s.mem())
  4212  	off := s.newValue2(sub, types.Types[types.TUINTPTR], pInt, s.sp)
  4213  	cond := s.newValue2(less, types.Types[types.TBOOL], off, frameSize)
  4214  
  4215  	b := s.endBlock()
  4216  	b.Kind = ssa.BlockIf
  4217  	b.Likely = ssa.BranchUnlikely // fast path is to not have to call into runtime
  4218  	b.SetControl(cond)
  4219  	b.AddEdgeTo(moveBlock)
  4220  	b.AddEdgeTo(mergeBlock)
  4221  
  4222  	// Move the slice to heap
  4223  	s.startBlock(moveBlock)
  4224  	var newSlice *ssa.Value
  4225  	if et.HasPointers() {
  4226  		typ := s.expr(n.RType)
  4227  		if n.PreserveCapacity {
  4228  			newSlice = s.rtcall(ir.Syms.MoveSlice, true, []*types.Type{slice.Type}, typ, p, l, c)[0]
  4229  		} else {
  4230  			newSlice = s.rtcall(ir.Syms.MoveSliceNoCap, true, []*types.Type{slice.Type}, typ, p, l)[0]
  4231  		}
  4232  	} else {
  4233  		elemSize := s.constInt(types.Types[types.TUINTPTR], et.Size())
  4234  		if n.PreserveCapacity {
  4235  			newSlice = s.rtcall(ir.Syms.MoveSliceNoScan, true, []*types.Type{slice.Type}, elemSize, p, l, c)[0]
  4236  		} else {
  4237  			newSlice = s.rtcall(ir.Syms.MoveSliceNoCapNoScan, true, []*types.Type{slice.Type}, elemSize, p, l)[0]
  4238  		}
  4239  	}
  4240  	// Decompose output slice
  4241  	s.vars[ptrVar] = s.newValue1(ssa.OpSlicePtr, pt, newSlice)
  4242  	s.vars[lenVar] = s.newValue1(ssa.OpSliceLen, types.Types[types.TINT], newSlice)
  4243  	s.vars[capVar] = s.newValue1(ssa.OpSliceCap, types.Types[types.TINT], newSlice)
  4244  	b = s.endBlock()
  4245  	b.AddEdgeTo(mergeBlock)
  4246  
  4247  	// Merge fast path (no moving) and slow path (moved)
  4248  	s.startBlock(mergeBlock)
  4249  	p = s.variable(ptrVar, pt)                      // generates phi for ptr
  4250  	l = s.variable(lenVar, types.Types[types.TINT]) // generates phi for len
  4251  	c = s.variable(capVar, types.Types[types.TINT]) // generates phi for cap
  4252  	delete(s.vars, ptrVar)
  4253  	delete(s.vars, lenVar)
  4254  	delete(s.vars, capVar)
  4255  	return s.newValue3(ssa.OpSliceMake, slice.Type, p, l, c)
  4256  }
  4257  
  4258  // minMax converts an OMIN/OMAX builtin call into SSA.
  4259  func (s *state) minMax(n *ir.CallExpr) *ssa.Value {
  4260  	// The OMIN/OMAX builtin is variadic, but its semantics are
  4261  	// equivalent to left-folding a binary min/max operation across the
  4262  	// arguments list.
  4263  	fold := func(op func(x, a *ssa.Value) *ssa.Value) *ssa.Value {
  4264  		x := s.expr(n.Args[0])
  4265  		for _, arg := range n.Args[1:] {
  4266  			x = op(x, s.expr(arg))
  4267  		}
  4268  		return x
  4269  	}
  4270  
  4271  	typ := n.Type()
  4272  
  4273  	if typ.IsFloat() || typ.IsString() {
  4274  		// min/max semantics for floats are tricky because of NaNs and
  4275  		// negative zero. Some architectures have instructions which
  4276  		// we can use to generate the right result. For others we must
  4277  		// call into the runtime instead.
  4278  		//
  4279  		// Strings are conceptually simpler, but we currently desugar
  4280  		// string comparisons during walk, not ssagen.
  4281  
  4282  		if typ.IsFloat() {
  4283  			hasIntrinsic := false
  4284  			switch Arch.LinkArch.Family {
  4285  			case sys.AMD64, sys.ARM64, sys.Loong64, sys.RISCV64, sys.S390X:
  4286  				hasIntrinsic = true
  4287  			case sys.PPC64:
  4288  				hasIntrinsic = buildcfg.GOPPC64 >= 9
  4289  			}
  4290  
  4291  			if hasIntrinsic {
  4292  				var op ssa.Op
  4293  				switch {
  4294  				case typ.Kind() == types.TFLOAT64 && n.Op() == ir.OMIN:
  4295  					op = ssa.OpMin64F
  4296  				case typ.Kind() == types.TFLOAT64 && n.Op() == ir.OMAX:
  4297  					op = ssa.OpMax64F
  4298  				case typ.Kind() == types.TFLOAT32 && n.Op() == ir.OMIN:
  4299  					op = ssa.OpMin32F
  4300  				case typ.Kind() == types.TFLOAT32 && n.Op() == ir.OMAX:
  4301  					op = ssa.OpMax32F
  4302  				}
  4303  				return fold(func(x, a *ssa.Value) *ssa.Value {
  4304  					return s.newValue2(op, typ, x, a)
  4305  				})
  4306  			}
  4307  		}
  4308  		var name string
  4309  		switch typ.Kind() {
  4310  		case types.TFLOAT32:
  4311  			switch n.Op() {
  4312  			case ir.OMIN:
  4313  				name = "fmin32"
  4314  			case ir.OMAX:
  4315  				name = "fmax32"
  4316  			}
  4317  		case types.TFLOAT64:
  4318  			switch n.Op() {
  4319  			case ir.OMIN:
  4320  				name = "fmin64"
  4321  			case ir.OMAX:
  4322  				name = "fmax64"
  4323  			}
  4324  		case types.TSTRING:
  4325  			switch n.Op() {
  4326  			case ir.OMIN:
  4327  				name = "strmin"
  4328  			case ir.OMAX:
  4329  				name = "strmax"
  4330  			}
  4331  		}
  4332  		fn := typecheck.LookupRuntimeFunc(name)
  4333  
  4334  		return fold(func(x, a *ssa.Value) *ssa.Value {
  4335  			return s.rtcall(fn, true, []*types.Type{typ}, x, a)[0]
  4336  		})
  4337  	}
  4338  
  4339  	if typ.IsInteger() {
  4340  		if Arch.LinkArch.Family == sys.RISCV64 && buildcfg.GORISCV64 >= 22 && typ.Size() == 8 {
  4341  			var op ssa.Op
  4342  			switch {
  4343  			case typ.IsSigned() && n.Op() == ir.OMIN:
  4344  				op = ssa.OpMin64
  4345  			case typ.IsSigned() && n.Op() == ir.OMAX:
  4346  				op = ssa.OpMax64
  4347  			case typ.IsUnsigned() && n.Op() == ir.OMIN:
  4348  				op = ssa.OpMin64u
  4349  			case typ.IsUnsigned() && n.Op() == ir.OMAX:
  4350  				op = ssa.OpMax64u
  4351  			}
  4352  			return fold(func(x, a *ssa.Value) *ssa.Value {
  4353  				return s.newValue2(op, typ, x, a)
  4354  			})
  4355  		}
  4356  	}
  4357  
  4358  	lt := s.ssaOp(ir.OLT, typ)
  4359  
  4360  	return fold(func(x, a *ssa.Value) *ssa.Value {
  4361  		switch n.Op() {
  4362  		case ir.OMIN:
  4363  			// a < x ? a : x
  4364  			return s.ternary(s.newValue2(lt, types.Types[types.TBOOL], a, x), a, x)
  4365  		case ir.OMAX:
  4366  			// x < a ? a : x
  4367  			return s.ternary(s.newValue2(lt, types.Types[types.TBOOL], x, a), a, x)
  4368  		}
  4369  		panic("unreachable")
  4370  	})
  4371  }
  4372  
  4373  // ternary emits code to evaluate cond ? x : y.
  4374  func (s *state) ternary(cond, x, y *ssa.Value) *ssa.Value {
  4375  	// Note that we need a new ternaryVar each time (unlike okVar where we can
  4376  	// reuse the variable) because it might have a different type every time.
  4377  	ternaryVar := ssaMarker("ternary")
  4378  
  4379  	bThen := s.f.NewBlock(ssa.BlockPlain)
  4380  	bElse := s.f.NewBlock(ssa.BlockPlain)
  4381  	bEnd := s.f.NewBlock(ssa.BlockPlain)
  4382  
  4383  	b := s.endBlock()
  4384  	b.Kind = ssa.BlockIf
  4385  	b.SetControl(cond)
  4386  	b.AddEdgeTo(bThen)
  4387  	b.AddEdgeTo(bElse)
  4388  
  4389  	s.startBlock(bThen)
  4390  	s.vars[ternaryVar] = x
  4391  	s.endBlock().AddEdgeTo(bEnd)
  4392  
  4393  	s.startBlock(bElse)
  4394  	s.vars[ternaryVar] = y
  4395  	s.endBlock().AddEdgeTo(bEnd)
  4396  
  4397  	s.startBlock(bEnd)
  4398  	r := s.variable(ternaryVar, x.Type)
  4399  	delete(s.vars, ternaryVar)
  4400  	return r
  4401  }
  4402  
  4403  // condBranch evaluates the boolean expression cond and branches to yes
  4404  // if cond is true and no if cond is false.
  4405  // This function is intended to handle && and || better than just calling
  4406  // s.expr(cond) and branching on the result.
  4407  func (s *state) condBranch(cond ir.Node, yes, no *ssa.Block, likely int8) {
  4408  	switch cond.Op() {
  4409  	case ir.OANDAND:
  4410  		cond := cond.(*ir.LogicalExpr)
  4411  		mid := s.f.NewBlock(ssa.BlockPlain)
  4412  		s.stmtList(cond.Init())
  4413  		s.condBranch(cond.X, mid, no, max(likely, 0))
  4414  		s.startBlock(mid)
  4415  		s.condBranch(cond.Y, yes, no, likely)
  4416  		return
  4417  		// Note: if likely==1, then both recursive calls pass 1.
  4418  		// If likely==-1, then we don't have enough information to decide
  4419  		// whether the first branch is likely or not. So we pass 0 for
  4420  		// the likeliness of the first branch.
  4421  		// TODO: have the frontend give us branch prediction hints for
  4422  		// OANDAND and OOROR nodes (if it ever has such info).
  4423  	case ir.OOROR:
  4424  		cond := cond.(*ir.LogicalExpr)
  4425  		mid := s.f.NewBlock(ssa.BlockPlain)
  4426  		s.stmtList(cond.Init())
  4427  		s.condBranch(cond.X, yes, mid, min(likely, 0))
  4428  		s.startBlock(mid)
  4429  		s.condBranch(cond.Y, yes, no, likely)
  4430  		return
  4431  		// Note: if likely==-1, then both recursive calls pass -1.
  4432  		// If likely==1, then we don't have enough info to decide
  4433  		// the likelihood of the first branch.
  4434  	case ir.ONOT:
  4435  		cond := cond.(*ir.UnaryExpr)
  4436  		s.stmtList(cond.Init())
  4437  		s.condBranch(cond.X, no, yes, -likely)
  4438  		return
  4439  	case ir.OCONVNOP:
  4440  		cond := cond.(*ir.ConvExpr)
  4441  		s.stmtList(cond.Init())
  4442  		s.condBranch(cond.X, yes, no, likely)
  4443  		return
  4444  	}
  4445  	c := s.expr(cond)
  4446  	b := s.endBlock()
  4447  	b.Kind = ssa.BlockIf
  4448  	b.SetControl(c)
  4449  	b.Likely = ssa.BranchPrediction(likely) // gc and ssa both use -1/0/+1 for likeliness
  4450  	b.AddEdgeTo(yes)
  4451  	b.AddEdgeTo(no)
  4452  }
  4453  
  4454  type skipMask uint8
  4455  
  4456  const (
  4457  	skipPtr skipMask = 1 << iota
  4458  	skipLen
  4459  	skipCap
  4460  )
  4461  
  4462  // assign does left = right.
  4463  // Right has already been evaluated to ssa, left has not.
  4464  // If deref is true, then we do left = *right instead (and right has already been nil-checked).
  4465  // If deref is true and right == nil, just do left = 0.
  4466  // skip indicates assignments (at the top level) that can be avoided.
  4467  // mayOverlap indicates whether left&right might partially overlap in memory. Default is false.
  4468  func (s *state) assign(left ir.Node, right *ssa.Value, deref bool, skip skipMask) {
  4469  	s.assignWhichMayOverlap(left, right, deref, skip, false)
  4470  }
  4471  func (s *state) assignWhichMayOverlap(left ir.Node, right *ssa.Value, deref bool, skip skipMask, mayOverlap bool) {
  4472  	if left.Op() == ir.ONAME && ir.IsBlank(left) {
  4473  		return
  4474  	}
  4475  	t := left.Type()
  4476  	types.CalcSize(t)
  4477  	if s.canSSA(left) {
  4478  		if deref {
  4479  			s.Fatalf("can SSA LHS %v but not RHS %s", left, right)
  4480  		}
  4481  		if left.Op() == ir.ODOT {
  4482  			// We're assigning to a field of an ssa-able value.
  4483  			// We need to build a new structure with the new value for the
  4484  			// field we're assigning and the old values for the other fields.
  4485  			// For instance:
  4486  			//   type T struct {a, b, c int}
  4487  			//   var T x
  4488  			//   x.b = 5
  4489  			// For the x.b = 5 assignment we want to generate x = T{x.a, 5, x.c}
  4490  
  4491  			// Grab information about the structure type.
  4492  			left := left.(*ir.SelectorExpr)
  4493  			t := left.X.Type()
  4494  			nf := t.NumFields()
  4495  			idx := fieldIdx(left)
  4496  
  4497  			// Grab old value of structure.
  4498  			old := s.expr(left.X)
  4499  
  4500  			if left.Type().Size() == 0 {
  4501  				// Nothing to do when assigning zero-sized things.
  4502  				return
  4503  			}
  4504  
  4505  			// Make new structure.
  4506  			new := s.newValue0(ssa.OpStructMake, t)
  4507  
  4508  			// Add fields as args.
  4509  			for i := 0; i < nf; i++ {
  4510  				if i == idx {
  4511  					new.AddArg(right)
  4512  				} else {
  4513  					new.AddArg(s.newValue1I(ssa.OpStructSelect, t.FieldType(i), int64(i), old))
  4514  				}
  4515  			}
  4516  
  4517  			// Recursively assign the new value we've made to the base of the dot op.
  4518  			s.assign(left.X, new, false, 0)
  4519  			// TODO: do we need to update named values here?
  4520  			return
  4521  		}
  4522  		if left.Op() == ir.OINDEX && left.(*ir.IndexExpr).X.Type().IsArray() {
  4523  			left := left.(*ir.IndexExpr)
  4524  			s.pushLine(left.Pos())
  4525  			defer s.popLine()
  4526  			// We're assigning to an element of an ssa-able array.
  4527  			// a[i] = v
  4528  			t := left.X.Type()
  4529  			n := t.NumElem()
  4530  
  4531  			i := s.expr(left.Index) // index
  4532  			if n == 0 {
  4533  				// The bounds check must fail.  Might as well
  4534  				// ignore the actual index and just use zeros.
  4535  				z := s.constInt(types.Types[types.TINT], 0)
  4536  				s.boundsCheck(z, z, ssa.BoundsIndex, false)
  4537  				return
  4538  			}
  4539  			if n != 1 {
  4540  				// This can happen in weird, always-panics cases, like:
  4541  				//     var x [0][2]int
  4542  				//     x[i][j] = 5
  4543  				// We know it always panics because the LHS is ssa-able,
  4544  				// and arrays of length > 1 can't be ssa-able unless
  4545  				// they are somewhere inside an outer [0].
  4546  				// We can ignore the actual assignment, it is dynamically
  4547  				// unreachable. See issue 77635.
  4548  				return
  4549  			}
  4550  			if t.Size() == 0 {
  4551  				return
  4552  			}
  4553  
  4554  			// Rewrite to a = [1]{v}
  4555  			len := s.constInt(types.Types[types.TINT], 1)
  4556  			s.boundsCheck(i, len, ssa.BoundsIndex, false) // checks i == 0
  4557  			v := s.newValue1(ssa.OpArrayMake1, t, right)
  4558  			s.assign(left.X, v, false, 0)
  4559  			return
  4560  		}
  4561  		left := left.(*ir.Name)
  4562  		// Update variable assignment.
  4563  		s.vars[left] = right
  4564  		s.addNamedValue(left, right)
  4565  		return
  4566  	}
  4567  
  4568  	// If this assignment clobbers an entire local variable, then emit
  4569  	// OpVarDef so liveness analysis knows the variable is redefined.
  4570  	if base, ok := clobberBase(left).(*ir.Name); ok && base.OnStack() && skip == 0 && (t.HasPointers() || ssa.IsMergeCandidate(base)) {
  4571  		s.vars[memVar] = s.newValue1Apos(ssa.OpVarDef, types.TypeMem, base, s.mem(), !ir.IsAutoTmp(base))
  4572  	}
  4573  
  4574  	// Left is not ssa-able. Compute its address.
  4575  	addr := s.addr(left)
  4576  	if ir.IsReflectHeaderDataField(left) {
  4577  		// Package unsafe's documentation says storing pointers into
  4578  		// reflect.SliceHeader and reflect.StringHeader's Data fields
  4579  		// is valid, even though they have type uintptr (#19168).
  4580  		// Mark it pointer type to signal the writebarrier pass to
  4581  		// insert a write barrier.
  4582  		t = types.Types[types.TUNSAFEPTR]
  4583  	}
  4584  	if deref {
  4585  		// Treat as a mem->mem move.
  4586  		if right == nil {
  4587  			s.zero(t, addr)
  4588  		} else {
  4589  			s.moveWhichMayOverlap(t, addr, right, mayOverlap)
  4590  		}
  4591  		return
  4592  	}
  4593  	// Treat as a store.
  4594  	s.storeType(t, addr, right, skip, !ir.IsAutoTmp(left))
  4595  }
  4596  
  4597  // zeroVal returns the zero value for type t.
  4598  func (s *state) zeroVal(t *types.Type) *ssa.Value {
  4599  	if t.Size() == 0 {
  4600  		return s.entryNewValue0(ssa.OpEmpty, t)
  4601  	}
  4602  	switch {
  4603  	case t.IsInteger():
  4604  		switch t.Size() {
  4605  		case 1:
  4606  			return s.constInt8(t, 0)
  4607  		case 2:
  4608  			return s.constInt16(t, 0)
  4609  		case 4:
  4610  			return s.constInt32(t, 0)
  4611  		case 8:
  4612  			return s.constInt64(t, 0)
  4613  		default:
  4614  			s.Fatalf("bad sized integer type %v", t)
  4615  		}
  4616  	case t.IsFloat():
  4617  		switch t.Size() {
  4618  		case 4:
  4619  			return s.constFloat32(t, 0)
  4620  		case 8:
  4621  			return s.constFloat64(t, 0)
  4622  		default:
  4623  			s.Fatalf("bad sized float type %v", t)
  4624  		}
  4625  	case t.IsComplex():
  4626  		switch t.Size() {
  4627  		case 8:
  4628  			z := s.constFloat32(types.Types[types.TFLOAT32], 0)
  4629  			return s.entryNewValue2(ssa.OpComplexMake, t, z, z)
  4630  		case 16:
  4631  			z := s.constFloat64(types.Types[types.TFLOAT64], 0)
  4632  			return s.entryNewValue2(ssa.OpComplexMake, t, z, z)
  4633  		default:
  4634  			s.Fatalf("bad sized complex type %v", t)
  4635  		}
  4636  
  4637  	case t.IsString():
  4638  		return s.constEmptyString(t)
  4639  	case t.IsPtrShaped():
  4640  		return s.constNil(t)
  4641  	case t.IsBoolean():
  4642  		return s.constBool(false)
  4643  	case t.IsInterface():
  4644  		return s.constInterface(t)
  4645  	case t.IsSlice():
  4646  		return s.constSlice(t)
  4647  	case isStructNotSIMD(t):
  4648  		n := t.NumFields()
  4649  		v := s.entryNewValue0(ssa.OpStructMake, t)
  4650  		for i := 0; i < n; i++ {
  4651  			v.AddArg(s.zeroVal(t.FieldType(i)))
  4652  		}
  4653  		return v
  4654  	case t.IsArray() && t.NumElem() == 1:
  4655  		return s.entryNewValue1(ssa.OpArrayMake1, t, s.zeroVal(t.Elem()))
  4656  	case t.IsSIMD():
  4657  		return s.newValue0(ssa.OpZeroSIMD, t)
  4658  	}
  4659  	s.Fatalf("zero for type %v not implemented", t)
  4660  	return nil
  4661  }
  4662  
  4663  type callKind int8
  4664  
  4665  const (
  4666  	callNormal callKind = iota
  4667  	callDefer
  4668  	callDeferStack
  4669  	callGo
  4670  	callTail
  4671  )
  4672  
  4673  type sfRtCallDef struct {
  4674  	rtfn  *obj.LSym
  4675  	rtype types.Kind
  4676  }
  4677  
  4678  var softFloatOps map[ssa.Op]sfRtCallDef
  4679  
  4680  func softfloatInit() {
  4681  	// Some of these operations get transformed by sfcall.
  4682  	softFloatOps = map[ssa.Op]sfRtCallDef{
  4683  		ssa.OpAdd32F: {typecheck.LookupRuntimeFunc("fadd32"), types.TFLOAT32},
  4684  		ssa.OpAdd64F: {typecheck.LookupRuntimeFunc("fadd64"), types.TFLOAT64},
  4685  		ssa.OpSub32F: {typecheck.LookupRuntimeFunc("fadd32"), types.TFLOAT32},
  4686  		ssa.OpSub64F: {typecheck.LookupRuntimeFunc("fadd64"), types.TFLOAT64},
  4687  		ssa.OpMul32F: {typecheck.LookupRuntimeFunc("fmul32"), types.TFLOAT32},
  4688  		ssa.OpMul64F: {typecheck.LookupRuntimeFunc("fmul64"), types.TFLOAT64},
  4689  		ssa.OpDiv32F: {typecheck.LookupRuntimeFunc("fdiv32"), types.TFLOAT32},
  4690  		ssa.OpDiv64F: {typecheck.LookupRuntimeFunc("fdiv64"), types.TFLOAT64},
  4691  
  4692  		ssa.OpEq64F:   {typecheck.LookupRuntimeFunc("feq64"), types.TBOOL},
  4693  		ssa.OpEq32F:   {typecheck.LookupRuntimeFunc("feq32"), types.TBOOL},
  4694  		ssa.OpNeq64F:  {typecheck.LookupRuntimeFunc("feq64"), types.TBOOL},
  4695  		ssa.OpNeq32F:  {typecheck.LookupRuntimeFunc("feq32"), types.TBOOL},
  4696  		ssa.OpLess64F: {typecheck.LookupRuntimeFunc("fgt64"), types.TBOOL},
  4697  		ssa.OpLess32F: {typecheck.LookupRuntimeFunc("fgt32"), types.TBOOL},
  4698  		ssa.OpLeq64F:  {typecheck.LookupRuntimeFunc("fge64"), types.TBOOL},
  4699  		ssa.OpLeq32F:  {typecheck.LookupRuntimeFunc("fge32"), types.TBOOL},
  4700  
  4701  		ssa.OpCvt32to32F:  {typecheck.LookupRuntimeFunc("fint32to32"), types.TFLOAT32},
  4702  		ssa.OpCvt32Fto32:  {typecheck.LookupRuntimeFunc("f32toint32"), types.TINT32},
  4703  		ssa.OpCvt64to32F:  {typecheck.LookupRuntimeFunc("fint64to32"), types.TFLOAT32},
  4704  		ssa.OpCvt32Fto64:  {typecheck.LookupRuntimeFunc("f32toint64"), types.TINT64},
  4705  		ssa.OpCvt64Uto32F: {typecheck.LookupRuntimeFunc("fuint64to32"), types.TFLOAT32},
  4706  		ssa.OpCvt32Fto64U: {typecheck.LookupRuntimeFunc("f32touint64"), types.TUINT64},
  4707  		ssa.OpCvt32to64F:  {typecheck.LookupRuntimeFunc("fint32to64"), types.TFLOAT64},
  4708  		ssa.OpCvt64Fto32:  {typecheck.LookupRuntimeFunc("f64toint32"), types.TINT32},
  4709  		ssa.OpCvt64to64F:  {typecheck.LookupRuntimeFunc("fint64to64"), types.TFLOAT64},
  4710  		ssa.OpCvt64Fto64:  {typecheck.LookupRuntimeFunc("f64toint64"), types.TINT64},
  4711  		ssa.OpCvt64Uto64F: {typecheck.LookupRuntimeFunc("fuint64to64"), types.TFLOAT64},
  4712  		ssa.OpCvt64Fto64U: {typecheck.LookupRuntimeFunc("f64touint64"), types.TUINT64},
  4713  		ssa.OpCvt32Fto64F: {typecheck.LookupRuntimeFunc("f32to64"), types.TFLOAT64},
  4714  		ssa.OpCvt64Fto32F: {typecheck.LookupRuntimeFunc("f64to32"), types.TFLOAT32},
  4715  	}
  4716  }
  4717  
  4718  // TODO: do not emit sfcall if operation can be optimized to constant in later
  4719  // opt phase
  4720  func (s *state) sfcall(op ssa.Op, args ...*ssa.Value) (*ssa.Value, bool) {
  4721  	f2i := func(t *types.Type) *types.Type {
  4722  		switch t.Kind() {
  4723  		case types.TFLOAT32:
  4724  			return types.Types[types.TUINT32]
  4725  		case types.TFLOAT64:
  4726  			return types.Types[types.TUINT64]
  4727  		}
  4728  		return t
  4729  	}
  4730  
  4731  	if callDef, ok := softFloatOps[op]; ok {
  4732  		switch op {
  4733  		case ssa.OpLess32F,
  4734  			ssa.OpLess64F,
  4735  			ssa.OpLeq32F,
  4736  			ssa.OpLeq64F:
  4737  			args[0], args[1] = args[1], args[0]
  4738  		case ssa.OpSub32F,
  4739  			ssa.OpSub64F:
  4740  			args[1] = s.newValue1(s.ssaOp(ir.ONEG, types.Types[callDef.rtype]), args[1].Type, args[1])
  4741  		}
  4742  
  4743  		// runtime functions take uints for floats and returns uints.
  4744  		// Convert to uints so we use the right calling convention.
  4745  		for i, a := range args {
  4746  			if a.Type.IsFloat() {
  4747  				args[i] = s.newValue1(ssa.OpCopy, f2i(a.Type), a)
  4748  			}
  4749  		}
  4750  
  4751  		rt := types.Types[callDef.rtype]
  4752  		result := s.rtcall(callDef.rtfn, true, []*types.Type{f2i(rt)}, args...)[0]
  4753  		if rt.IsFloat() {
  4754  			result = s.newValue1(ssa.OpCopy, rt, result)
  4755  		}
  4756  		if op == ssa.OpNeq32F || op == ssa.OpNeq64F {
  4757  			result = s.newValue1(ssa.OpNot, result.Type, result)
  4758  		}
  4759  		return result, true
  4760  	}
  4761  	return nil, false
  4762  }
  4763  
  4764  // split breaks up a tuple-typed value into its 2 parts.
  4765  func (s *state) split(v *ssa.Value) (*ssa.Value, *ssa.Value) {
  4766  	p0 := s.newValue1(ssa.OpSelect0, v.Type.FieldType(0), v)
  4767  	p1 := s.newValue1(ssa.OpSelect1, v.Type.FieldType(1), v)
  4768  	return p0, p1
  4769  }
  4770  
  4771  // intrinsicCall converts a call to a recognized intrinsic function into the intrinsic SSA operation.
  4772  func (s *state) intrinsicCall(n *ir.CallExpr) *ssa.Value {
  4773  	v := findIntrinsic(n.Fun.Sym())(s, n, s.intrinsicArgs(n))
  4774  	if ssa.IntrinsicsDebug > 0 {
  4775  		x := v
  4776  		if x == nil {
  4777  			x = s.mem()
  4778  		}
  4779  		if x.Op == ssa.OpSelect0 || x.Op == ssa.OpSelect1 {
  4780  			x = x.Args[0]
  4781  		}
  4782  		base.WarnfAt(n.Pos(), "intrinsic substitution for %v with %s", n.Fun.Sym().Name, x.LongString())
  4783  	}
  4784  	return v
  4785  }
  4786  
  4787  // intrinsicArgs extracts args from n, evaluates them to SSA values, and returns them.
  4788  func (s *state) intrinsicArgs(n *ir.CallExpr) []*ssa.Value {
  4789  	args := make([]*ssa.Value, len(n.Args))
  4790  	for i, n := range n.Args {
  4791  		args[i] = s.expr(n)
  4792  	}
  4793  	return args
  4794  }
  4795  
  4796  // openDeferRecord adds code to evaluate and store the function for an open-code defer
  4797  // call, and records info about the defer, so we can generate proper code on the
  4798  // exit paths. n is the sub-node of the defer node that is the actual function
  4799  // call. We will also record funcdata information on where the function is stored
  4800  // (as well as the deferBits variable), and this will enable us to run the proper
  4801  // defer calls during panics.
  4802  func (s *state) openDeferRecord(n *ir.CallExpr) {
  4803  	if len(n.Args) != 0 || n.Op() != ir.OCALLFUNC || n.Fun.Type().NumResults() != 0 {
  4804  		s.Fatalf("defer call with arguments or results: %v", n)
  4805  	}
  4806  
  4807  	opendefer := &openDeferInfo{
  4808  		n: n,
  4809  	}
  4810  	fn := n.Fun
  4811  	// We must always store the function value in a stack slot for the
  4812  	// runtime panic code to use. But in the defer exit code, we will
  4813  	// call the function directly if it is a static function.
  4814  	closureVal := s.expr(fn)
  4815  	closure := s.openDeferSave(fn.Type(), closureVal)
  4816  	opendefer.closureNode = closure.Aux.(*ir.Name)
  4817  	if !(fn.Op() == ir.ONAME && fn.(*ir.Name).Class == ir.PFUNC) {
  4818  		opendefer.closure = closure
  4819  	}
  4820  	index := len(s.openDefers)
  4821  	s.openDefers = append(s.openDefers, opendefer)
  4822  
  4823  	// Update deferBits only after evaluation and storage to stack of
  4824  	// the function is successful.
  4825  	bitvalue := s.constInt8(types.Types[types.TUINT8], 1<<uint(index))
  4826  	newDeferBits := s.newValue2(ssa.OpOr8, types.Types[types.TUINT8], s.variable(deferBitsVar, types.Types[types.TUINT8]), bitvalue)
  4827  	s.vars[deferBitsVar] = newDeferBits
  4828  	s.store(types.Types[types.TUINT8], s.deferBitsAddr, newDeferBits)
  4829  }
  4830  
  4831  // openDeferSave generates SSA nodes to store a value (with type t) for an
  4832  // open-coded defer at an explicit autotmp location on the stack, so it can be
  4833  // reloaded and used for the appropriate call on exit. Type t must be a function type
  4834  // (therefore SSAable). val is the value to be stored. The function returns an SSA
  4835  // value representing a pointer to the autotmp location.
  4836  func (s *state) openDeferSave(t *types.Type, val *ssa.Value) *ssa.Value {
  4837  	if !ssa.CanSSA(t) {
  4838  		s.Fatalf("openDeferSave of non-SSA-able type %v val=%v", t, val)
  4839  	}
  4840  	if !t.HasPointers() {
  4841  		s.Fatalf("openDeferSave of pointerless type %v val=%v", t, val)
  4842  	}
  4843  	pos := val.Pos
  4844  	temp := typecheck.TempAt(pos.WithNotStmt(), s.curfn, t)
  4845  	temp.SetOpenDeferSlot(true)
  4846  	temp.SetFrameOffset(int64(len(s.openDefers))) // so cmpstackvarlt can order them
  4847  	var addrTemp *ssa.Value
  4848  	// Use OpVarLive to make sure stack slot for the closure is not removed by
  4849  	// dead-store elimination
  4850  	if s.curBlock.ID != s.f.Entry.ID {
  4851  		// Force the tmp storing this defer function to be declared in the entry
  4852  		// block, so that it will be live for the defer exit code (which will
  4853  		// actually access it only if the associated defer call has been activated).
  4854  		if t.HasPointers() {
  4855  			s.defvars[s.f.Entry.ID][memVar] = s.f.Entry.NewValue1A(src.NoXPos, ssa.OpVarDef, types.TypeMem, temp, s.defvars[s.f.Entry.ID][memVar])
  4856  		}
  4857  		s.defvars[s.f.Entry.ID][memVar] = s.f.Entry.NewValue1A(src.NoXPos, ssa.OpVarLive, types.TypeMem, temp, s.defvars[s.f.Entry.ID][memVar])
  4858  		addrTemp = s.f.Entry.NewValue2A(src.NoXPos, ssa.OpLocalAddr, types.NewPtr(temp.Type()), temp, s.sp, s.defvars[s.f.Entry.ID][memVar])
  4859  	} else {
  4860  		// Special case if we're still in the entry block. We can't use
  4861  		// the above code, since s.defvars[s.f.Entry.ID] isn't defined
  4862  		// until we end the entry block with s.endBlock().
  4863  		if t.HasPointers() {
  4864  			s.vars[memVar] = s.newValue1Apos(ssa.OpVarDef, types.TypeMem, temp, s.mem(), false)
  4865  		}
  4866  		s.vars[memVar] = s.newValue1Apos(ssa.OpVarLive, types.TypeMem, temp, s.mem(), false)
  4867  		addrTemp = s.newValue2Apos(ssa.OpLocalAddr, types.NewPtr(temp.Type()), temp, s.sp, s.mem(), false)
  4868  	}
  4869  	// Since we may use this temp during exit depending on the
  4870  	// deferBits, we must define it unconditionally on entry.
  4871  	// Therefore, we must make sure it is zeroed out in the entry
  4872  	// block if it contains pointers, else GC may wrongly follow an
  4873  	// uninitialized pointer value.
  4874  	temp.SetNeedzero(true)
  4875  	// We are storing to the stack, hence we can avoid the full checks in
  4876  	// storeType() (no write barrier) and do a simple store().
  4877  	s.store(t, addrTemp, val)
  4878  	return addrTemp
  4879  }
  4880  
  4881  // openDeferExit generates SSA for processing all the open coded defers at exit.
  4882  // The code involves loading deferBits, and checking each of the bits to see if
  4883  // the corresponding defer statement was executed. For each bit that is turned
  4884  // on, the associated defer call is made.
  4885  func (s *state) openDeferExit() {
  4886  	deferExit := s.f.NewBlock(ssa.BlockPlain)
  4887  	s.endBlock().AddEdgeTo(deferExit)
  4888  	s.startBlock(deferExit)
  4889  	s.lastDeferExit = deferExit
  4890  	s.lastDeferCount = len(s.openDefers)
  4891  	zeroval := s.constInt8(types.Types[types.TUINT8], 0)
  4892  	// Test for and run defers in reverse order
  4893  	for i := len(s.openDefers) - 1; i >= 0; i-- {
  4894  		r := s.openDefers[i]
  4895  		bCond := s.f.NewBlock(ssa.BlockPlain)
  4896  		bEnd := s.f.NewBlock(ssa.BlockPlain)
  4897  
  4898  		deferBits := s.variable(deferBitsVar, types.Types[types.TUINT8])
  4899  		// Generate code to check if the bit associated with the current
  4900  		// defer is set.
  4901  		bitval := s.constInt8(types.Types[types.TUINT8], 1<<uint(i))
  4902  		andval := s.newValue2(ssa.OpAnd8, types.Types[types.TUINT8], deferBits, bitval)
  4903  		eqVal := s.newValue2(ssa.OpEq8, types.Types[types.TBOOL], andval, zeroval)
  4904  		b := s.endBlock()
  4905  		b.Kind = ssa.BlockIf
  4906  		b.SetControl(eqVal)
  4907  		b.AddEdgeTo(bEnd)
  4908  		b.AddEdgeTo(bCond)
  4909  		bCond.AddEdgeTo(bEnd)
  4910  		s.startBlock(bCond)
  4911  
  4912  		// Clear this bit in deferBits and force store back to stack, so
  4913  		// we will not try to re-run this defer call if this defer call panics.
  4914  		nbitval := s.newValue1(ssa.OpCom8, types.Types[types.TUINT8], bitval)
  4915  		maskedval := s.newValue2(ssa.OpAnd8, types.Types[types.TUINT8], deferBits, nbitval)
  4916  		s.store(types.Types[types.TUINT8], s.deferBitsAddr, maskedval)
  4917  		// Use this value for following tests, so we keep previous
  4918  		// bits cleared.
  4919  		s.vars[deferBitsVar] = maskedval
  4920  
  4921  		// Generate code to call the function call of the defer, using the
  4922  		// closure that were stored in argtmps at the point of the defer
  4923  		// statement.
  4924  		fn := r.n.Fun
  4925  		stksize := fn.Type().ArgWidth()
  4926  		var callArgs []*ssa.Value
  4927  		var call *ssa.Value
  4928  		if r.closure != nil {
  4929  			v := s.load(r.closure.Type.Elem(), r.closure)
  4930  			s.maybeNilCheckClosure(v, callDefer)
  4931  			codeptr := s.rawLoad(types.Types[types.TUINTPTR], v)
  4932  			aux := ssa.ClosureAuxCall(s.f.ABIDefault.ABIAnalyzeTypes(nil, nil))
  4933  			call = s.newValue2A(ssa.OpClosureLECall, aux.LateExpansionResultType(), aux, codeptr, v)
  4934  		} else {
  4935  			aux := ssa.StaticAuxCall(fn.(*ir.Name).Linksym(), s.f.ABIDefault.ABIAnalyzeTypes(nil, nil))
  4936  			call = s.newValue0A(ssa.OpStaticLECall, aux.LateExpansionResultType(), aux)
  4937  		}
  4938  		callArgs = append(callArgs, s.mem())
  4939  		call.AddArgs(callArgs...)
  4940  		call.AuxInt = stksize
  4941  		s.vars[memVar] = s.newValue1I(ssa.OpSelectN, types.TypeMem, 0, call)
  4942  		// Make sure that the stack slots with pointers are kept live
  4943  		// through the call (which is a pre-emption point). Also, we will
  4944  		// use the first call of the last defer exit to compute liveness
  4945  		// for the deferreturn, so we want all stack slots to be live.
  4946  		if r.closureNode != nil {
  4947  			s.vars[memVar] = s.newValue1Apos(ssa.OpVarLive, types.TypeMem, r.closureNode, s.mem(), false)
  4948  		}
  4949  
  4950  		s.endBlock()
  4951  		s.startBlock(bEnd)
  4952  	}
  4953  }
  4954  
  4955  func (s *state) callResult(n *ir.CallExpr, k callKind) *ssa.Value {
  4956  	return s.call(n, k, false, nil)
  4957  }
  4958  
  4959  func (s *state) callAddr(n *ir.CallExpr, k callKind) *ssa.Value {
  4960  	return s.call(n, k, true, nil)
  4961  }
  4962  
  4963  // Calls the function n using the specified call type.
  4964  // Returns the address of the return value (or nil if none).
  4965  func (s *state) call(n *ir.CallExpr, k callKind, returnResultAddr bool, deferExtra ir.Expr) *ssa.Value {
  4966  	s.prevCall = nil
  4967  	var calleeLSym *obj.LSym // target function (if static)
  4968  	var closure *ssa.Value   // ptr to closure to run (if dynamic)
  4969  	var codeptr *ssa.Value   // ptr to target code (if dynamic)
  4970  	var dextra *ssa.Value    // defer extra arg
  4971  	var rcvr *ssa.Value      // receiver to set
  4972  	fn := n.Fun
  4973  	var ACArgs []*types.Type    // AuxCall args
  4974  	var ACResults []*types.Type // AuxCall results
  4975  	var callArgs []*ssa.Value   // For late-expansion, the args themselves (not stored, args to the call instead).
  4976  
  4977  	callABI := s.f.ABIDefault
  4978  
  4979  	if k != callNormal && k != callTail && (len(n.Args) != 0 || n.Op() == ir.OCALLINTER || n.Fun.Type().NumResults() != 0) {
  4980  		s.Fatalf("go/defer call with arguments: %v", n)
  4981  	}
  4982  
  4983  	isCallDeferRangeFunc := false
  4984  
  4985  	switch n.Op() {
  4986  	case ir.OCALLFUNC:
  4987  		if (k == callNormal || k == callTail) && fn.Op() == ir.ONAME && fn.(*ir.Name).Class == ir.PFUNC {
  4988  			fn := fn.(*ir.Name)
  4989  			calleeLSym = callTargetLSym(fn)
  4990  			if buildcfg.Experiment.RegabiArgs {
  4991  				// This is a static call, so it may be
  4992  				// a direct call to a non-ABIInternal
  4993  				// function. fn.Func may be nil for
  4994  				// some compiler-generated functions,
  4995  				// but those are all ABIInternal.
  4996  				if fn.Func != nil {
  4997  					callABI = abiForFunc(fn.Func, s.f.ABI0, s.f.ABI1)
  4998  				}
  4999  			} else {
  5000  				// TODO(register args) remove after register abi is working
  5001  				inRegistersImported := fn.Pragma()&ir.RegisterParams != 0
  5002  				inRegistersSamePackage := fn.Func != nil && fn.Func.Pragma&ir.RegisterParams != 0
  5003  				if inRegistersImported || inRegistersSamePackage {
  5004  					callABI = s.f.ABI1
  5005  				}
  5006  			}
  5007  			if fn := n.Fun.Sym().Name; n.Fun.Sym().Pkg == ir.Pkgs.Runtime && fn == "deferrangefunc" {
  5008  				isCallDeferRangeFunc = true
  5009  			}
  5010  			break
  5011  		}
  5012  		closure = s.expr(fn)
  5013  		if k != callDefer && k != callDeferStack {
  5014  			// Deferred nil function needs to panic when the function is invoked,
  5015  			// not the point of defer statement.
  5016  			s.maybeNilCheckClosure(closure, k)
  5017  		}
  5018  	case ir.OCALLINTER:
  5019  		if fn.Op() != ir.ODOTINTER {
  5020  			s.Fatalf("OCALLINTER: n.Left not an ODOTINTER: %v", fn.Op())
  5021  		}
  5022  		fn := fn.(*ir.SelectorExpr)
  5023  		var iclosure *ssa.Value
  5024  		iclosure, rcvr = s.getClosureAndRcvr(fn)
  5025  		if k == callNormal || k == callTail {
  5026  			codeptr = s.load(types.Types[types.TUINTPTR], iclosure)
  5027  		} else {
  5028  			closure = iclosure
  5029  		}
  5030  	}
  5031  	if deferExtra != nil {
  5032  		dextra = s.expr(deferExtra)
  5033  	}
  5034  
  5035  	params := callABI.ABIAnalyze(n.Fun.Type(), false /* Do not set (register) nNames from caller side -- can cause races. */)
  5036  	types.CalcSize(fn.Type())
  5037  	stksize := params.ArgWidth() // includes receiver, args, and results
  5038  
  5039  	res := n.Fun.Type().Results()
  5040  	if k == callNormal || k == callTail {
  5041  		for _, p := range params.OutParams() {
  5042  			ACResults = append(ACResults, p.Type)
  5043  		}
  5044  	}
  5045  
  5046  	var call *ssa.Value
  5047  	if k == callDeferStack {
  5048  		if stksize != 0 {
  5049  			s.Fatalf("deferprocStack with non-zero stack size %d: %v", stksize, n)
  5050  		}
  5051  		// Make a defer struct on the stack.
  5052  		t := deferstruct()
  5053  		n, addr := s.temp(n.Pos(), t)
  5054  		n.SetNonMergeable(true)
  5055  		s.store(closure.Type,
  5056  			s.newValue1I(ssa.OpOffPtr, closure.Type.PtrTo(), t.FieldOff(deferStructFnField), addr),
  5057  			closure)
  5058  
  5059  		// Call runtime.deferprocStack with pointer to _defer record.
  5060  		ACArgs = append(ACArgs, types.Types[types.TUINTPTR])
  5061  		aux := ssa.StaticAuxCall(ir.Syms.DeferprocStack, s.f.ABIDefault.ABIAnalyzeTypes(ACArgs, ACResults))
  5062  		callArgs = append(callArgs, addr, s.mem())
  5063  		call = s.newValue0A(ssa.OpStaticLECall, aux.LateExpansionResultType(), aux)
  5064  		call.AddArgs(callArgs...)
  5065  		call.AuxInt = int64(types.PtrSize) // deferprocStack takes a *_defer arg
  5066  	} else {
  5067  		// Store arguments to stack, including defer/go arguments and receiver for method calls.
  5068  		// These are written in SP-offset order.
  5069  		argStart := base.Ctxt.Arch.FixedFrameSize
  5070  		// Defer/go args.
  5071  		if k != callNormal && k != callTail {
  5072  			// Write closure (arg to newproc/deferproc).
  5073  			ACArgs = append(ACArgs, types.Types[types.TUINTPTR]) // not argExtra
  5074  			callArgs = append(callArgs, closure)
  5075  			stksize += int64(types.PtrSize)
  5076  			argStart += int64(types.PtrSize)
  5077  			if dextra != nil {
  5078  				// Extra token of type any for deferproc
  5079  				ACArgs = append(ACArgs, types.Types[types.TINTER])
  5080  				callArgs = append(callArgs, dextra)
  5081  				stksize += 2 * int64(types.PtrSize)
  5082  				argStart += 2 * int64(types.PtrSize)
  5083  			}
  5084  		}
  5085  
  5086  		// Set receiver (for interface calls).
  5087  		if rcvr != nil {
  5088  			callArgs = append(callArgs, rcvr)
  5089  		}
  5090  
  5091  		// Write args.
  5092  		t := n.Fun.Type()
  5093  		args := n.Args
  5094  
  5095  		for _, p := range params.InParams() { // includes receiver for interface calls
  5096  			ACArgs = append(ACArgs, p.Type)
  5097  		}
  5098  
  5099  		// Split the entry block if there are open defers, because later calls to
  5100  		// openDeferSave may cause a mismatch between the mem for an OpDereference
  5101  		// and the call site which uses it. See #49282.
  5102  		if s.curBlock.ID == s.f.Entry.ID && s.hasOpenDefers {
  5103  			b := s.endBlock()
  5104  			b.Kind = ssa.BlockPlain
  5105  			curb := s.f.NewBlock(ssa.BlockPlain)
  5106  			b.AddEdgeTo(curb)
  5107  			s.startBlock(curb)
  5108  		}
  5109  
  5110  		for i, n := range args {
  5111  			callArgs = append(callArgs, s.putArg(n, t.Param(i).Type))
  5112  		}
  5113  
  5114  		callArgs = append(callArgs, s.mem())
  5115  
  5116  		// call target
  5117  		switch {
  5118  		case k == callDefer:
  5119  			sym := ir.Syms.Deferproc
  5120  			if dextra != nil {
  5121  				sym = ir.Syms.Deferprocat
  5122  			}
  5123  			aux := ssa.StaticAuxCall(sym, s.f.ABIDefault.ABIAnalyzeTypes(ACArgs, ACResults)) // TODO paramResultInfo for Deferproc(at)
  5124  			call = s.newValue0A(ssa.OpStaticLECall, aux.LateExpansionResultType(), aux)
  5125  		case k == callGo:
  5126  			aux := ssa.StaticAuxCall(ir.Syms.Newproc, s.f.ABIDefault.ABIAnalyzeTypes(ACArgs, ACResults))
  5127  			call = s.newValue0A(ssa.OpStaticLECall, aux.LateExpansionResultType(), aux) // TODO paramResultInfo for Newproc
  5128  		case closure != nil:
  5129  			// rawLoad because loading the code pointer from a
  5130  			// closure is always safe, but IsSanitizerSafeAddr
  5131  			// can't always figure that out currently, and it's
  5132  			// critical that we not clobber any arguments already
  5133  			// stored onto the stack.
  5134  			codeptr = s.rawLoad(types.Types[types.TUINTPTR], closure)
  5135  			aux := ssa.ClosureAuxCall(callABI.ABIAnalyzeTypes(ACArgs, ACResults))
  5136  			call = s.newValue2A(ssa.OpClosureLECall, aux.LateExpansionResultType(), aux, codeptr, closure)
  5137  		case codeptr != nil:
  5138  			// Note that the "receiver" parameter is nil because the actual receiver is the first input parameter.
  5139  			aux := ssa.InterfaceAuxCall(params)
  5140  			call = s.newValue1A(ssa.OpInterLECall, aux.LateExpansionResultType(), aux, codeptr)
  5141  			if k == callTail {
  5142  				call.Op = ssa.OpTailLECallInter
  5143  				stksize = 0 // Tail call does not use stack. We reuse caller's frame.
  5144  			}
  5145  		case calleeLSym != nil:
  5146  			aux := ssa.StaticAuxCall(calleeLSym, params)
  5147  			call = s.newValue0A(ssa.OpStaticLECall, aux.LateExpansionResultType(), aux)
  5148  			if k == callTail {
  5149  				call.Op = ssa.OpTailLECall
  5150  				stksize = 0 // Tail call does not use stack. We reuse caller's frame.
  5151  			}
  5152  		default:
  5153  			s.Fatalf("bad call type %v %v", n.Op(), n)
  5154  		}
  5155  		call.AddArgs(callArgs...)
  5156  		call.AuxInt = stksize // Call operations carry the argsize of the callee along with them
  5157  	}
  5158  	s.prevCall = call
  5159  	s.vars[memVar] = s.newValue1I(ssa.OpSelectN, types.TypeMem, int64(len(ACResults)), call)
  5160  	// Insert VarLive opcodes.
  5161  	for _, v := range n.KeepAlive {
  5162  		if !v.Addrtaken() {
  5163  			s.Fatalf("KeepAlive variable %v must have Addrtaken set", v)
  5164  		}
  5165  		switch v.Class {
  5166  		case ir.PAUTO, ir.PPARAM, ir.PPARAMOUT:
  5167  		default:
  5168  			s.Fatalf("KeepAlive variable %v must be Auto or Arg", v)
  5169  		}
  5170  		s.vars[memVar] = s.newValue1A(ssa.OpVarLive, types.TypeMem, v, s.mem())
  5171  	}
  5172  
  5173  	// Build result value (before we might end the defer block, below).
  5174  	var result *ssa.Value
  5175  	if len(res) == 0 || k != callNormal {
  5176  		result = nil
  5177  	} else {
  5178  		fp := res[0]
  5179  		if returnResultAddr {
  5180  			result = s.resultAddrOfCall(call, 0, fp.Type)
  5181  		} else {
  5182  			result = s.newValue1I(ssa.OpSelectN, fp.Type, 0, call)
  5183  		}
  5184  	}
  5185  
  5186  	// Finish block for defers
  5187  	if k == callDefer || k == callDeferStack || isCallDeferRangeFunc {
  5188  		b := s.endBlock()
  5189  		b.Kind = ssa.BlockDefer
  5190  		b.SetControl(call)
  5191  		bNext := s.f.NewBlock(ssa.BlockPlain)
  5192  		b.AddEdgeTo(bNext)
  5193  		r := s.f.DeferReturn // Share a single deferreturn among all defers
  5194  		if r == nil {
  5195  			r = s.f.NewBlock(ssa.BlockPlain)
  5196  			s.startBlock(r)
  5197  			s.exit()
  5198  			s.f.DeferReturn = r
  5199  		}
  5200  		b.AddEdgeTo(r) // Add recover edge to exit code.  This is a fake edge to keep the block live.
  5201  		b.Likely = ssa.BranchLikely
  5202  		s.startBlock(bNext)
  5203  	}
  5204  
  5205  	return result
  5206  }
  5207  
  5208  // maybeNilCheckClosure checks if a nil check of a closure is needed in some
  5209  // architecture-dependent situations and, if so, emits the nil check.
  5210  func (s *state) maybeNilCheckClosure(closure *ssa.Value, k callKind) {
  5211  	if Arch.LinkArch.Family == sys.Wasm || buildcfg.GOOS == "aix" && k != callGo {
  5212  		// On AIX, the closure needs to be verified as fn can be nil, except if it's a call go. This needs to be handled by the runtime to have the "go of nil func value" error.
  5213  		// TODO(neelance): On other architectures this should be eliminated by the optimization steps
  5214  		s.nilCheck(closure)
  5215  	}
  5216  }
  5217  
  5218  // getClosureAndRcvr returns values for the appropriate closure and receiver of an
  5219  // interface call
  5220  func (s *state) getClosureAndRcvr(fn *ir.SelectorExpr) (*ssa.Value, *ssa.Value) {
  5221  	i := s.expr(fn.X)
  5222  	itab := s.newValue1(ssa.OpITab, types.Types[types.TUINTPTR], i)
  5223  	s.nilCheck(itab)
  5224  	itabidx := fn.Offset() + rttype.ITab.OffsetOf("Fun")
  5225  	closure := s.newValue1I(ssa.OpOffPtr, s.f.Config.Types.UintptrPtr, itabidx, itab)
  5226  	rcvr := s.newValue1(ssa.OpIData, s.f.Config.Types.BytePtr, i)
  5227  	return closure, rcvr
  5228  }
  5229  
  5230  // etypesign returns the signed-ness of e, for integer/pointer etypes.
  5231  // -1 means signed, +1 means unsigned, 0 means non-integer/non-pointer.
  5232  func etypesign(e types.Kind) int8 {
  5233  	switch e {
  5234  	case types.TINT8, types.TINT16, types.TINT32, types.TINT64, types.TINT:
  5235  		return -1
  5236  	case types.TUINT8, types.TUINT16, types.TUINT32, types.TUINT64, types.TUINT, types.TUINTPTR, types.TUNSAFEPTR:
  5237  		return +1
  5238  	}
  5239  	return 0
  5240  }
  5241  
  5242  // addr converts the address of the expression n to SSA, adds it to s and returns the SSA result.
  5243  // The value that the returned Value represents is guaranteed to be non-nil.
  5244  func (s *state) addr(n ir.Node) *ssa.Value {
  5245  	if n.Op() != ir.ONAME {
  5246  		s.pushLine(n.Pos())
  5247  		defer s.popLine()
  5248  	}
  5249  
  5250  	if s.canSSA(n) {
  5251  		// This happens in weird, always-panics cases, like:
  5252  		//     var x [0][2]int
  5253  		//     x[i][j] = 5
  5254  		// The outer assignment, ...[j] = 5, is a fine
  5255  		// assignment to do, but requires computing the address
  5256  		// &x[i], which will always panic when evaluated.
  5257  		// We just return something reasonable in this case.
  5258  		// It will be dynamically unreachable. See issue 77635.
  5259  		return s.newValue1A(ssa.OpAddr, n.Type().PtrTo(), ir.Syms.Zerobase, s.sb)
  5260  	}
  5261  
  5262  	t := types.NewPtr(n.Type())
  5263  	linksymOffset := func(lsym *obj.LSym, offset int64) *ssa.Value {
  5264  		v := s.entryNewValue1A(ssa.OpAddr, t, lsym, s.sb)
  5265  		// TODO: Make OpAddr use AuxInt as well as Aux.
  5266  		if offset != 0 {
  5267  			v = s.entryNewValue1I(ssa.OpOffPtr, v.Type, offset, v)
  5268  		}
  5269  		return v
  5270  	}
  5271  	switch n.Op() {
  5272  	case ir.OLINKSYMOFFSET:
  5273  		no := n.(*ir.LinksymOffsetExpr)
  5274  		return linksymOffset(no.Linksym, no.Offset_)
  5275  	case ir.ONAME:
  5276  		n := n.(*ir.Name)
  5277  		if n.Heapaddr != nil {
  5278  			return s.expr(n.Heapaddr)
  5279  		}
  5280  		switch n.Class {
  5281  		case ir.PEXTERN:
  5282  			// global variable
  5283  			return linksymOffset(n.Linksym(), 0)
  5284  		case ir.PPARAM:
  5285  			// parameter slot
  5286  			v := s.decladdrs[n]
  5287  			if v != nil {
  5288  				return v
  5289  			}
  5290  			s.Fatalf("addr of undeclared ONAME %v. declared: %v", n, s.decladdrs)
  5291  			return nil
  5292  		case ir.PAUTO:
  5293  			return s.newValue2Apos(ssa.OpLocalAddr, t, n, s.sp, s.mem(), !ir.IsAutoTmp(n))
  5294  
  5295  		case ir.PPARAMOUT: // Same as PAUTO -- cannot generate LEA early.
  5296  			// ensure that we reuse symbols for out parameters so
  5297  			// that cse works on their addresses
  5298  			return s.newValue2Apos(ssa.OpLocalAddr, t, n, s.sp, s.mem(), true)
  5299  		default:
  5300  			s.Fatalf("variable address class %v not implemented", n.Class)
  5301  			return nil
  5302  		}
  5303  	case ir.ORESULT:
  5304  		// load return from callee
  5305  		n := n.(*ir.ResultExpr)
  5306  		return s.resultAddrOfCall(s.prevCall, n.Index, n.Type())
  5307  	case ir.OINDEX:
  5308  		n := n.(*ir.IndexExpr)
  5309  		if n.X.Type().IsSlice() {
  5310  			a := s.expr(n.X)
  5311  			i := s.expr(n.Index)
  5312  			len := s.newValue1(ssa.OpSliceLen, types.Types[types.TINT], a)
  5313  			i = s.boundsCheck(i, len, ssa.BoundsIndex, n.Bounded())
  5314  			p := s.newValue1(ssa.OpSlicePtr, t, a)
  5315  			return s.newValue2(ssa.OpPtrIndex, t, p, i)
  5316  		} else { // array
  5317  			a := s.addr(n.X)
  5318  			i := s.expr(n.Index)
  5319  			len := s.constInt(types.Types[types.TINT], n.X.Type().NumElem())
  5320  			i = s.boundsCheck(i, len, ssa.BoundsIndex, n.Bounded())
  5321  			return s.newValue2(ssa.OpPtrIndex, types.NewPtr(n.X.Type().Elem()), a, i)
  5322  		}
  5323  	case ir.ODEREF:
  5324  		n := n.(*ir.StarExpr)
  5325  		return s.exprPtr(n.X, n.Bounded(), n.Pos())
  5326  	case ir.ODOT:
  5327  		n := n.(*ir.SelectorExpr)
  5328  		p := s.addr(n.X)
  5329  		return s.newValue1I(ssa.OpOffPtr, t, n.Offset(), p)
  5330  	case ir.ODOTPTR:
  5331  		n := n.(*ir.SelectorExpr)
  5332  		p := s.exprPtr(n.X, n.Bounded(), n.Pos())
  5333  		return s.newValue1I(ssa.OpOffPtr, t, n.Offset(), p)
  5334  	case ir.OCONVNOP:
  5335  		n := n.(*ir.ConvExpr)
  5336  		if n.Type() == n.X.Type() {
  5337  			return s.addr(n.X)
  5338  		}
  5339  		addr := s.addr(n.X)
  5340  		return s.newValue1(ssa.OpCopy, t, addr) // ensure that addr has the right type
  5341  	case ir.OCALLFUNC, ir.OCALLINTER:
  5342  		n := n.(*ir.CallExpr)
  5343  		return s.callAddr(n, callNormal)
  5344  	case ir.ODOTTYPE, ir.ODYNAMICDOTTYPE:
  5345  		var v *ssa.Value
  5346  		if n.Op() == ir.ODOTTYPE {
  5347  			v, _ = s.dottype(n.(*ir.TypeAssertExpr), false)
  5348  		} else {
  5349  			v, _ = s.dynamicDottype(n.(*ir.DynamicTypeAssertExpr), false)
  5350  		}
  5351  		if v.Op != ssa.OpLoad {
  5352  			s.Fatalf("dottype of non-load")
  5353  		}
  5354  		if v.Args[1] != s.mem() {
  5355  			s.Fatalf("memory no longer live from dottype load")
  5356  		}
  5357  		return v.Args[0]
  5358  	default:
  5359  		s.Fatalf("unhandled addr %v", n.Op())
  5360  		return nil
  5361  	}
  5362  }
  5363  
  5364  // canSSA reports whether n is SSA-able.
  5365  // n must be an ONAME (or an ODOT sequence with an ONAME base).
  5366  func (s *state) canSSA(n ir.Node) bool {
  5367  	if base.Flag.N != 0 {
  5368  		return false
  5369  	}
  5370  	for {
  5371  		nn := n
  5372  		if nn.Op() == ir.ODOT {
  5373  			nn := nn.(*ir.SelectorExpr)
  5374  			n = nn.X
  5375  			continue
  5376  		}
  5377  		if nn.Op() == ir.OINDEX {
  5378  			nn := nn.(*ir.IndexExpr)
  5379  			if nn.X.Type().IsArray() {
  5380  				n = nn.X
  5381  				continue
  5382  			}
  5383  		}
  5384  		break
  5385  	}
  5386  	if n.Op() != ir.ONAME {
  5387  		return false
  5388  	}
  5389  	return s.canSSAName(n.(*ir.Name)) && ssa.CanSSA(n.Type())
  5390  }
  5391  
  5392  func (s *state) canSSAName(name *ir.Name) bool {
  5393  	if name.Addrtaken() || !name.OnStack() {
  5394  		return false
  5395  	}
  5396  	switch name.Class {
  5397  	case ir.PPARAMOUT:
  5398  		if s.hasdefer {
  5399  			// TODO: handle this case? Named return values must be
  5400  			// in memory so that the deferred function can see them.
  5401  			// Maybe do: if !strings.HasPrefix(n.String(), "~") { return false }
  5402  			// Or maybe not, see issue 18860.  Even unnamed return values
  5403  			// must be written back so if a defer recovers, the caller can see them.
  5404  			return false
  5405  		}
  5406  		if s.cgoUnsafeArgs {
  5407  			// Cgo effectively takes the address of all result args,
  5408  			// but the compiler can't see that.
  5409  			return false
  5410  		}
  5411  	}
  5412  	return true
  5413  	// TODO: try to make more variables SSAable?
  5414  }
  5415  
  5416  // exprPtr evaluates n to a pointer and nil-checks it.
  5417  func (s *state) exprPtr(n ir.Node, bounded bool, lineno src.XPos) *ssa.Value {
  5418  	p := s.expr(n)
  5419  	if bounded || n.NonNil() {
  5420  		if s.f.Frontend().Debug_checknil() && lineno.Line() > 1 {
  5421  			s.f.Warnl(lineno, "removed nil check")
  5422  		}
  5423  		return p
  5424  	}
  5425  	p = s.nilCheck(p)
  5426  	return p
  5427  }
  5428  
  5429  // nilCheck generates nil pointer checking code.
  5430  // Used only for automatically inserted nil checks,
  5431  // not for user code like 'x != nil'.
  5432  // Returns a "definitely not nil" copy of x to ensure proper ordering
  5433  // of the uses of the post-nilcheck pointer.
  5434  func (s *state) nilCheck(ptr *ssa.Value) *ssa.Value {
  5435  	if base.Debug.DisableNil != 0 || s.curfn.NilCheckDisabled() {
  5436  		return ptr
  5437  	}
  5438  	return s.newValue2(ssa.OpNilCheck, ptr.Type, ptr, s.mem())
  5439  }
  5440  
  5441  // boundsCheck generates bounds checking code. Checks if 0 <= idx <[=] len, branches to exit if not.
  5442  // Starts a new block on return.
  5443  // On input, len must be converted to full int width and be nonnegative.
  5444  // Returns idx converted to full int width.
  5445  // If bounded is true then caller guarantees the index is not out of bounds
  5446  // (but boundsCheck will still extend the index to full int width).
  5447  func (s *state) boundsCheck(idx, len *ssa.Value, kind ssa.BoundsKind, bounded bool) *ssa.Value {
  5448  	idx = s.extendIndex(idx, len, kind, bounded)
  5449  
  5450  	if bounded || base.Flag.B != 0 {
  5451  		// If bounded or bounds checking is flag-disabled, then no check necessary,
  5452  		// just return the extended index.
  5453  		//
  5454  		// Here, bounded == true if the compiler generated the index itself,
  5455  		// such as in the expansion of a slice initializer. These indexes are
  5456  		// compiler-generated, not Go program variables, so they cannot be
  5457  		// attacker-controlled, so we can omit Spectre masking as well.
  5458  		//
  5459  		// Note that we do not want to omit Spectre masking in code like:
  5460  		//
  5461  		//	if 0 <= i && i < len(x) {
  5462  		//		use(x[i])
  5463  		//	}
  5464  		//
  5465  		// Lucky for us, bounded==false for that code.
  5466  		// In that case (handled below), we emit a bound check (and Spectre mask)
  5467  		// and then the prove pass will remove the bounds check.
  5468  		// In theory the prove pass could potentially remove certain
  5469  		// Spectre masks, but it's very delicate and probably better
  5470  		// to be conservative and leave them all in.
  5471  		return idx
  5472  	}
  5473  
  5474  	bNext := s.f.NewBlock(ssa.BlockPlain)
  5475  	bPanic := s.f.NewBlock(ssa.BlockExit)
  5476  
  5477  	if !idx.Type.IsSigned() {
  5478  		switch kind {
  5479  		case ssa.BoundsIndex:
  5480  			kind = ssa.BoundsIndexU
  5481  		case ssa.BoundsSliceAlen:
  5482  			kind = ssa.BoundsSliceAlenU
  5483  		case ssa.BoundsSliceAcap:
  5484  			kind = ssa.BoundsSliceAcapU
  5485  		case ssa.BoundsSliceB:
  5486  			kind = ssa.BoundsSliceBU
  5487  		case ssa.BoundsSlice3Alen:
  5488  			kind = ssa.BoundsSlice3AlenU
  5489  		case ssa.BoundsSlice3Acap:
  5490  			kind = ssa.BoundsSlice3AcapU
  5491  		case ssa.BoundsSlice3B:
  5492  			kind = ssa.BoundsSlice3BU
  5493  		case ssa.BoundsSlice3C:
  5494  			kind = ssa.BoundsSlice3CU
  5495  		}
  5496  	}
  5497  
  5498  	var cmp *ssa.Value
  5499  	if kind == ssa.BoundsIndex || kind == ssa.BoundsIndexU {
  5500  		cmp = s.newValue2(ssa.OpIsInBounds, types.Types[types.TBOOL], idx, len)
  5501  	} else {
  5502  		cmp = s.newValue2(ssa.OpIsSliceInBounds, types.Types[types.TBOOL], idx, len)
  5503  	}
  5504  	b := s.endBlock()
  5505  	b.Kind = ssa.BlockIf
  5506  	b.SetControl(cmp)
  5507  	b.Likely = ssa.BranchLikely
  5508  	b.AddEdgeTo(bNext)
  5509  	b.AddEdgeTo(bPanic)
  5510  
  5511  	s.startBlock(bPanic)
  5512  	if Arch.LinkArch.Family == sys.Wasm {
  5513  		// TODO(khr): figure out how to do "register" based calling convention for bounds checks.
  5514  		// Should be similar to gcWriteBarrier, but I can't make it work.
  5515  		s.rtcall(BoundsCheckFunc[kind], false, nil, idx, len)
  5516  	} else {
  5517  		mem := s.newValue3I(ssa.OpPanicBounds, types.TypeMem, int64(kind), idx, len, s.mem())
  5518  		s.endBlock().SetControl(mem)
  5519  	}
  5520  	s.startBlock(bNext)
  5521  
  5522  	// In Spectre index mode, apply an appropriate mask to avoid speculative out-of-bounds accesses.
  5523  	if base.Flag.Cfg.SpectreIndex {
  5524  		op := ssa.OpSpectreIndex
  5525  		if kind != ssa.BoundsIndex && kind != ssa.BoundsIndexU {
  5526  			op = ssa.OpSpectreSliceIndex
  5527  		}
  5528  		idx = s.newValue2(op, types.Types[types.TINT], idx, len)
  5529  	}
  5530  
  5531  	return idx
  5532  }
  5533  
  5534  // If cmp (a bool) is false, panic using the given function.
  5535  func (s *state) check(cmp *ssa.Value, fn *obj.LSym) {
  5536  	b := s.endBlock()
  5537  	b.Kind = ssa.BlockIf
  5538  	b.SetControl(cmp)
  5539  	b.Likely = ssa.BranchLikely
  5540  	bNext := s.f.NewBlock(ssa.BlockPlain)
  5541  	line := s.peekPos()
  5542  	pos := base.Ctxt.PosTable.Pos(line)
  5543  	fl := funcLine{f: fn, base: pos.Base(), line: pos.Line()}
  5544  	bPanic := s.panics[fl]
  5545  	if bPanic == nil {
  5546  		bPanic = s.f.NewBlock(ssa.BlockPlain)
  5547  		s.panics[fl] = bPanic
  5548  		s.startBlock(bPanic)
  5549  		// The panic call takes/returns memory to ensure that the right
  5550  		// memory state is observed if the panic happens.
  5551  		s.rtcall(fn, false, nil)
  5552  	}
  5553  	b.AddEdgeTo(bNext)
  5554  	b.AddEdgeTo(bPanic)
  5555  	s.startBlock(bNext)
  5556  }
  5557  
  5558  func (s *state) intDivide(n ir.Node, a, b *ssa.Value) *ssa.Value {
  5559  	needcheck := true
  5560  	switch b.Op {
  5561  	case ssa.OpConst8, ssa.OpConst16, ssa.OpConst32, ssa.OpConst64:
  5562  		if b.AuxInt != 0 {
  5563  			needcheck = false
  5564  		}
  5565  	}
  5566  	if needcheck {
  5567  		// do a size-appropriate check for zero
  5568  		cmp := s.newValue2(s.ssaOp(ir.ONE, n.Type()), types.Types[types.TBOOL], b, s.zeroVal(n.Type()))
  5569  		s.check(cmp, ir.Syms.Panicdivide)
  5570  	}
  5571  	return s.newValue2(s.ssaOp(n.Op(), n.Type()), a.Type, a, b)
  5572  }
  5573  
  5574  // rtcall issues a call to the given runtime function fn with the listed args.
  5575  // Returns a slice of results of the given result types.
  5576  // The call is added to the end of the current block.
  5577  // If returns is false, the block is marked as an exit block.
  5578  func (s *state) rtcall(fn *obj.LSym, returns bool, results []*types.Type, args ...*ssa.Value) []*ssa.Value {
  5579  	s.prevCall = nil
  5580  	// Write args to the stack
  5581  	off := base.Ctxt.Arch.FixedFrameSize
  5582  	var callArgs []*ssa.Value
  5583  	var callArgTypes []*types.Type
  5584  
  5585  	for _, arg := range args {
  5586  		t := arg.Type
  5587  		off = types.RoundUp(off, t.Alignment())
  5588  		size := t.Size()
  5589  		callArgs = append(callArgs, arg)
  5590  		callArgTypes = append(callArgTypes, t)
  5591  		off += size
  5592  	}
  5593  	off = types.RoundUp(off, int64(types.RegSize))
  5594  
  5595  	// Issue call
  5596  	var call *ssa.Value
  5597  	aux := ssa.StaticAuxCall(fn, s.f.ABIDefault.ABIAnalyzeTypes(callArgTypes, results))
  5598  	callArgs = append(callArgs, s.mem())
  5599  	call = s.newValue0A(ssa.OpStaticLECall, aux.LateExpansionResultType(), aux)
  5600  	call.AddArgs(callArgs...)
  5601  	s.vars[memVar] = s.newValue1I(ssa.OpSelectN, types.TypeMem, int64(len(results)), call)
  5602  
  5603  	if !returns {
  5604  		// Finish block
  5605  		b := s.endBlock()
  5606  		b.Kind = ssa.BlockExit
  5607  		b.SetControl(call)
  5608  		call.AuxInt = off - base.Ctxt.Arch.FixedFrameSize
  5609  		if len(results) > 0 {
  5610  			s.Fatalf("panic call can't have results")
  5611  		}
  5612  		return nil
  5613  	}
  5614  
  5615  	// Load results
  5616  	res := make([]*ssa.Value, len(results))
  5617  	for i, t := range results {
  5618  		off = types.RoundUp(off, t.Alignment())
  5619  		res[i] = s.resultOfCall(call, int64(i), t)
  5620  		off += t.Size()
  5621  	}
  5622  	off = types.RoundUp(off, int64(types.PtrSize))
  5623  
  5624  	// Remember how much callee stack space we needed.
  5625  	call.AuxInt = off
  5626  
  5627  	return res
  5628  }
  5629  
  5630  // do *left = right for type t.
  5631  func (s *state) storeType(t *types.Type, left, right *ssa.Value, skip skipMask, leftIsStmt bool) {
  5632  	s.instrument(t, left, instrumentWrite)
  5633  
  5634  	if skip == 0 && (!t.HasPointers() || ssa.IsStackAddr(left)) {
  5635  		// Known to not have write barrier. Store the whole type.
  5636  		s.vars[memVar] = s.newValue3Apos(ssa.OpStore, types.TypeMem, t, left, right, s.mem(), leftIsStmt)
  5637  		return
  5638  	}
  5639  
  5640  	// store scalar fields first, so write barrier stores for
  5641  	// pointer fields can be grouped together, and scalar values
  5642  	// don't need to be live across the write barrier call.
  5643  	// TODO: if the writebarrier pass knows how to reorder stores,
  5644  	// we can do a single store here as long as skip==0.
  5645  	s.storeTypeScalars(t, left, right, skip)
  5646  	if skip&skipPtr == 0 && t.HasPointers() {
  5647  		s.storeTypePtrs(t, left, right)
  5648  	}
  5649  }
  5650  
  5651  // do *left = right for all scalar (non-pointer) parts of t.
  5652  func (s *state) storeTypeScalars(t *types.Type, left, right *ssa.Value, skip skipMask) {
  5653  	switch {
  5654  	case t.IsBoolean() || t.IsInteger() || t.IsFloat() || t.IsComplex() || t.IsSIMD():
  5655  		s.store(t, left, right)
  5656  	case t.IsPtrShaped():
  5657  		if t.IsPtr() && t.Elem().NotInHeap() {
  5658  			s.store(t, left, right) // see issue 42032
  5659  		}
  5660  		// otherwise, no scalar fields.
  5661  	case t.IsString():
  5662  		if skip&skipLen != 0 {
  5663  			return
  5664  		}
  5665  		len := s.newValue1(ssa.OpStringLen, types.Types[types.TINT], right)
  5666  		lenAddr := s.newValue1I(ssa.OpOffPtr, s.f.Config.Types.IntPtr, s.config.PtrSize, left)
  5667  		s.store(types.Types[types.TINT], lenAddr, len)
  5668  	case t.IsSlice():
  5669  		if skip&skipLen == 0 {
  5670  			len := s.newValue1(ssa.OpSliceLen, types.Types[types.TINT], right)
  5671  			lenAddr := s.newValue1I(ssa.OpOffPtr, s.f.Config.Types.IntPtr, s.config.PtrSize, left)
  5672  			s.store(types.Types[types.TINT], lenAddr, len)
  5673  		}
  5674  		if skip&skipCap == 0 {
  5675  			cap := s.newValue1(ssa.OpSliceCap, types.Types[types.TINT], right)
  5676  			capAddr := s.newValue1I(ssa.OpOffPtr, s.f.Config.Types.IntPtr, 2*s.config.PtrSize, left)
  5677  			s.store(types.Types[types.TINT], capAddr, cap)
  5678  		}
  5679  	case t.IsInterface():
  5680  		// itab field doesn't need a write barrier (even though it is a pointer).
  5681  		itab := s.newValue1(ssa.OpITab, s.f.Config.Types.BytePtr, right)
  5682  		s.store(types.Types[types.TUINTPTR], left, itab)
  5683  	case isStructNotSIMD(t):
  5684  		n := t.NumFields()
  5685  		for i := 0; i < n; i++ {
  5686  			ft := t.FieldType(i)
  5687  			addr := s.newValue1I(ssa.OpOffPtr, ft.PtrTo(), t.FieldOff(i), left)
  5688  			val := s.newValue1I(ssa.OpStructSelect, ft, int64(i), right)
  5689  			s.storeTypeScalars(ft, addr, val, 0)
  5690  		}
  5691  	case t.IsArray() && t.Size() == 0:
  5692  		// nothing
  5693  	case t.IsArray() && t.NumElem() == 1:
  5694  		s.storeTypeScalars(t.Elem(), left, s.newValue1I(ssa.OpArraySelect, t.Elem(), 0, right), 0)
  5695  	default:
  5696  		s.Fatalf("bad write barrier type %v", t)
  5697  	}
  5698  }
  5699  
  5700  // do *left = right for all pointer parts of t.
  5701  func (s *state) storeTypePtrs(t *types.Type, left, right *ssa.Value) {
  5702  	switch {
  5703  	case t.IsPtrShaped():
  5704  		if t.IsPtr() && t.Elem().NotInHeap() {
  5705  			break // see issue 42032
  5706  		}
  5707  		s.store(t, left, right)
  5708  	case t.IsString():
  5709  		ptr := s.newValue1(ssa.OpStringPtr, s.f.Config.Types.BytePtr, right)
  5710  		s.store(s.f.Config.Types.BytePtr, left, ptr)
  5711  	case t.IsSlice():
  5712  		elType := types.NewPtr(t.Elem())
  5713  		ptr := s.newValue1(ssa.OpSlicePtr, elType, right)
  5714  		s.store(elType, left, ptr)
  5715  	case t.IsInterface():
  5716  		// itab field is treated as a scalar.
  5717  		idata := s.newValue1(ssa.OpIData, s.f.Config.Types.BytePtr, right)
  5718  		idataAddr := s.newValue1I(ssa.OpOffPtr, s.f.Config.Types.BytePtrPtr, s.config.PtrSize, left)
  5719  		s.store(s.f.Config.Types.BytePtr, idataAddr, idata)
  5720  	case isStructNotSIMD(t):
  5721  		n := t.NumFields()
  5722  		for i := 0; i < n; i++ {
  5723  			ft := t.FieldType(i)
  5724  			if !ft.HasPointers() {
  5725  				continue
  5726  			}
  5727  			addr := s.newValue1I(ssa.OpOffPtr, ft.PtrTo(), t.FieldOff(i), left)
  5728  			val := s.newValue1I(ssa.OpStructSelect, ft, int64(i), right)
  5729  			s.storeTypePtrs(ft, addr, val)
  5730  		}
  5731  	case t.IsArray() && t.Size() == 0:
  5732  		// nothing
  5733  	case t.IsArray() && t.NumElem() == 1:
  5734  		s.storeTypePtrs(t.Elem(), left, s.newValue1I(ssa.OpArraySelect, t.Elem(), 0, right))
  5735  	default:
  5736  		s.Fatalf("bad write barrier type %v", t)
  5737  	}
  5738  }
  5739  
  5740  // putArg evaluates n for the purpose of passing it as an argument to a function and returns the value for the call.
  5741  func (s *state) putArg(n ir.Node, t *types.Type) *ssa.Value {
  5742  	var a *ssa.Value
  5743  	if !ssa.CanSSA(t) {
  5744  		a = s.newValue2(ssa.OpDereference, t, s.addr(n), s.mem())
  5745  	} else {
  5746  		a = s.expr(n)
  5747  	}
  5748  	return a
  5749  }
  5750  
  5751  // slice computes the slice v[i:j:k] and returns ptr, len, and cap of result.
  5752  // i,j,k may be nil, in which case they are set to their default value.
  5753  // v may be a slice, string or pointer to an array.
  5754  func (s *state) slice(v, i, j, k *ssa.Value, bounded bool) (p, l, c *ssa.Value) {
  5755  	t := v.Type
  5756  	var ptr, len, cap *ssa.Value
  5757  	switch {
  5758  	case t.IsSlice():
  5759  		ptr = s.newValue1(ssa.OpSlicePtr, types.NewPtr(t.Elem()), v)
  5760  		len = s.newValue1(ssa.OpSliceLen, types.Types[types.TINT], v)
  5761  		cap = s.newValue1(ssa.OpSliceCap, types.Types[types.TINT], v)
  5762  	case t.IsString():
  5763  		ptr = s.newValue1(ssa.OpStringPtr, types.NewPtr(types.Types[types.TUINT8]), v)
  5764  		len = s.newValue1(ssa.OpStringLen, types.Types[types.TINT], v)
  5765  		cap = len
  5766  	case t.IsPtr():
  5767  		if !t.Elem().IsArray() {
  5768  			s.Fatalf("bad ptr to array in slice %v\n", t)
  5769  		}
  5770  		nv := s.nilCheck(v)
  5771  		ptr = s.newValue1(ssa.OpCopy, types.NewPtr(t.Elem().Elem()), nv)
  5772  		len = s.constInt(types.Types[types.TINT], t.Elem().NumElem())
  5773  		cap = len
  5774  	default:
  5775  		s.Fatalf("bad type in slice %v\n", t)
  5776  	}
  5777  
  5778  	// Set default values
  5779  	if i == nil {
  5780  		i = s.constInt(types.Types[types.TINT], 0)
  5781  	}
  5782  	if j == nil {
  5783  		j = len
  5784  	}
  5785  	three := true
  5786  	if k == nil {
  5787  		three = false
  5788  		k = cap
  5789  	}
  5790  
  5791  	// Panic if slice indices are not in bounds.
  5792  	// Make sure we check these in reverse order so that we're always
  5793  	// comparing against a value known to be nonnegative. See issue 28797.
  5794  	if three {
  5795  		if k != cap {
  5796  			kind := ssa.BoundsSlice3Alen
  5797  			if t.IsSlice() {
  5798  				kind = ssa.BoundsSlice3Acap
  5799  			}
  5800  			k = s.boundsCheck(k, cap, kind, bounded)
  5801  		}
  5802  		if j != k {
  5803  			j = s.boundsCheck(j, k, ssa.BoundsSlice3B, bounded)
  5804  		}
  5805  		i = s.boundsCheck(i, j, ssa.BoundsSlice3C, bounded)
  5806  	} else {
  5807  		if j != k {
  5808  			kind := ssa.BoundsSliceAlen
  5809  			if t.IsSlice() {
  5810  				kind = ssa.BoundsSliceAcap
  5811  			}
  5812  			j = s.boundsCheck(j, k, kind, bounded)
  5813  		}
  5814  		i = s.boundsCheck(i, j, ssa.BoundsSliceB, bounded)
  5815  	}
  5816  
  5817  	// Word-sized integer operations.
  5818  	subOp := s.ssaOp(ir.OSUB, types.Types[types.TINT])
  5819  	mulOp := s.ssaOp(ir.OMUL, types.Types[types.TINT])
  5820  	andOp := s.ssaOp(ir.OAND, types.Types[types.TINT])
  5821  
  5822  	// Calculate the length (rlen) and capacity (rcap) of the new slice.
  5823  	// For strings the capacity of the result is unimportant. However,
  5824  	// we use rcap to test if we've generated a zero-length slice.
  5825  	// Use length of strings for that.
  5826  	rlen := s.newValue2(subOp, types.Types[types.TINT], j, i)
  5827  	rcap := rlen
  5828  	if j != k && !t.IsString() {
  5829  		rcap = s.newValue2(subOp, types.Types[types.TINT], k, i)
  5830  	}
  5831  
  5832  	if (i.Op == ssa.OpConst64 || i.Op == ssa.OpConst32) && i.AuxInt == 0 {
  5833  		// No pointer arithmetic necessary.
  5834  		return ptr, rlen, rcap
  5835  	}
  5836  
  5837  	// Calculate the base pointer (rptr) for the new slice.
  5838  	//
  5839  	// Generate the following code assuming that indexes are in bounds.
  5840  	// The masking is to make sure that we don't generate a slice
  5841  	// that points to the next object in memory. We cannot just set
  5842  	// the pointer to nil because then we would create a nil slice or
  5843  	// string.
  5844  	//
  5845  	//     rcap = k - i
  5846  	//     rlen = j - i
  5847  	//     rptr = ptr + (mask(rcap) & (i * stride))
  5848  	//
  5849  	// Where mask(x) is 0 if x==0 and -1 if x>0 and stride is the width
  5850  	// of the element type.
  5851  	stride := s.constInt(types.Types[types.TINT], ptr.Type.Elem().Size())
  5852  
  5853  	// The delta is the number of bytes to offset ptr by.
  5854  	delta := s.newValue2(mulOp, types.Types[types.TINT], i, stride)
  5855  
  5856  	// If we're slicing to the point where the capacity is zero,
  5857  	// zero out the delta.
  5858  	mask := s.newValue1(ssa.OpSlicemask, types.Types[types.TINT], rcap)
  5859  	delta = s.newValue2(andOp, types.Types[types.TINT], delta, mask)
  5860  
  5861  	// Compute rptr = ptr + delta.
  5862  	rptr := s.newValue2(ssa.OpAddPtr, ptr.Type, ptr, delta)
  5863  
  5864  	return rptr, rlen, rcap
  5865  }
  5866  
  5867  type u642fcvtTab struct {
  5868  	leq, cvt2F, and, rsh, or, add ssa.Op
  5869  	one                           func(*state, *types.Type, int64) *ssa.Value
  5870  }
  5871  
  5872  var u64_f64 = u642fcvtTab{
  5873  	leq:   ssa.OpLeq64,
  5874  	cvt2F: ssa.OpCvt64to64F,
  5875  	and:   ssa.OpAnd64,
  5876  	rsh:   ssa.OpRsh64Ux64,
  5877  	or:    ssa.OpOr64,
  5878  	add:   ssa.OpAdd64F,
  5879  	one:   (*state).constInt64,
  5880  }
  5881  
  5882  var u64_f32 = u642fcvtTab{
  5883  	leq:   ssa.OpLeq64,
  5884  	cvt2F: ssa.OpCvt64to32F,
  5885  	and:   ssa.OpAnd64,
  5886  	rsh:   ssa.OpRsh64Ux64,
  5887  	or:    ssa.OpOr64,
  5888  	add:   ssa.OpAdd32F,
  5889  	one:   (*state).constInt64,
  5890  }
  5891  
  5892  func (s *state) uint64Tofloat64(n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  5893  	return s.uint64Tofloat(&u64_f64, n, x, ft, tt)
  5894  }
  5895  
  5896  func (s *state) uint64Tofloat32(n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  5897  	return s.uint64Tofloat(&u64_f32, n, x, ft, tt)
  5898  }
  5899  
  5900  func (s *state) uint64Tofloat(cvttab *u642fcvtTab, n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  5901  	// if x >= 0 {
  5902  	//    result = (floatY) x
  5903  	// } else {
  5904  	// 	  y = uintX(x) ; y = x & 1
  5905  	// 	  z = uintX(x) ; z = z >> 1
  5906  	// 	  z = z | y
  5907  	// 	  result = floatY(z)
  5908  	// 	  result = result + result
  5909  	// }
  5910  	//
  5911  	// Code borrowed from old code generator.
  5912  	// What's going on: large 64-bit "unsigned" looks like
  5913  	// negative number to hardware's integer-to-float
  5914  	// conversion. However, because the mantissa is only
  5915  	// 63 bits, we don't need the LSB, so instead we do an
  5916  	// unsigned right shift (divide by two), convert, and
  5917  	// double. However, before we do that, we need to be
  5918  	// sure that we do not lose a "1" if that made the
  5919  	// difference in the resulting rounding. Therefore, we
  5920  	// preserve it, and OR (not ADD) it back in. The case
  5921  	// that matters is when the eleven discarded bits are
  5922  	// equal to 10000000001; that rounds up, and the 1 cannot
  5923  	// be lost else it would round down if the LSB of the
  5924  	// candidate mantissa is 0.
  5925  
  5926  	cmp := s.newValue2(cvttab.leq, types.Types[types.TBOOL], s.zeroVal(ft), x)
  5927  
  5928  	b := s.endBlock()
  5929  	b.Kind = ssa.BlockIf
  5930  	b.SetControl(cmp)
  5931  	b.Likely = ssa.BranchLikely
  5932  
  5933  	bThen := s.f.NewBlock(ssa.BlockPlain)
  5934  	bElse := s.f.NewBlock(ssa.BlockPlain)
  5935  	bAfter := s.f.NewBlock(ssa.BlockPlain)
  5936  
  5937  	b.AddEdgeTo(bThen)
  5938  	s.startBlock(bThen)
  5939  	a0 := s.newValue1(cvttab.cvt2F, tt, x)
  5940  	s.vars[n] = a0
  5941  	s.endBlock()
  5942  	bThen.AddEdgeTo(bAfter)
  5943  
  5944  	b.AddEdgeTo(bElse)
  5945  	s.startBlock(bElse)
  5946  	one := cvttab.one(s, ft, 1)
  5947  	y := s.newValue2(cvttab.and, ft, x, one)
  5948  	z := s.newValue2(cvttab.rsh, ft, x, one)
  5949  	z = s.newValue2(cvttab.or, ft, z, y)
  5950  	a := s.newValue1(cvttab.cvt2F, tt, z)
  5951  	a1 := s.newValue2(cvttab.add, tt, a, a)
  5952  	s.vars[n] = a1
  5953  	s.endBlock()
  5954  	bElse.AddEdgeTo(bAfter)
  5955  
  5956  	s.startBlock(bAfter)
  5957  	return s.variable(n, n.Type())
  5958  }
  5959  
  5960  type u322fcvtTab struct {
  5961  	cvtI2F, cvtF2F ssa.Op
  5962  }
  5963  
  5964  var u32_f64 = u322fcvtTab{
  5965  	cvtI2F: ssa.OpCvt32to64F,
  5966  	cvtF2F: ssa.OpCopy,
  5967  }
  5968  
  5969  var u32_f32 = u322fcvtTab{
  5970  	cvtI2F: ssa.OpCvt32to32F,
  5971  	cvtF2F: ssa.OpCvt64Fto32F,
  5972  }
  5973  
  5974  func (s *state) uint32Tofloat64(n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  5975  	return s.uint32Tofloat(&u32_f64, n, x, ft, tt)
  5976  }
  5977  
  5978  func (s *state) uint32Tofloat32(n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  5979  	return s.uint32Tofloat(&u32_f32, n, x, ft, tt)
  5980  }
  5981  
  5982  func (s *state) uint32Tofloat(cvttab *u322fcvtTab, n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  5983  	// if x >= 0 {
  5984  	// 	result = floatY(x)
  5985  	// } else {
  5986  	// 	result = floatY(float64(x) + (1<<32))
  5987  	// }
  5988  	cmp := s.newValue2(ssa.OpLeq32, types.Types[types.TBOOL], s.zeroVal(ft), x)
  5989  	b := s.endBlock()
  5990  	b.Kind = ssa.BlockIf
  5991  	b.SetControl(cmp)
  5992  	b.Likely = ssa.BranchLikely
  5993  
  5994  	bThen := s.f.NewBlock(ssa.BlockPlain)
  5995  	bElse := s.f.NewBlock(ssa.BlockPlain)
  5996  	bAfter := s.f.NewBlock(ssa.BlockPlain)
  5997  
  5998  	b.AddEdgeTo(bThen)
  5999  	s.startBlock(bThen)
  6000  	a0 := s.newValue1(cvttab.cvtI2F, tt, x)
  6001  	s.vars[n] = a0
  6002  	s.endBlock()
  6003  	bThen.AddEdgeTo(bAfter)
  6004  
  6005  	b.AddEdgeTo(bElse)
  6006  	s.startBlock(bElse)
  6007  	a1 := s.newValue1(ssa.OpCvt32to64F, types.Types[types.TFLOAT64], x)
  6008  	twoToThe32 := s.constFloat64(types.Types[types.TFLOAT64], float64(1<<32))
  6009  	a2 := s.newValue2(ssa.OpAdd64F, types.Types[types.TFLOAT64], a1, twoToThe32)
  6010  	a3 := s.newValue1(cvttab.cvtF2F, tt, a2)
  6011  
  6012  	s.vars[n] = a3
  6013  	s.endBlock()
  6014  	bElse.AddEdgeTo(bAfter)
  6015  
  6016  	s.startBlock(bAfter)
  6017  	return s.variable(n, n.Type())
  6018  }
  6019  
  6020  // referenceTypeBuiltin generates code for the len/cap builtins for maps and channels.
  6021  func (s *state) referenceTypeBuiltin(n *ir.UnaryExpr, x *ssa.Value) *ssa.Value {
  6022  	if !n.X.Type().IsMap() && !n.X.Type().IsChan() {
  6023  		s.Fatalf("node must be a map or a channel")
  6024  	}
  6025  	if n.X.Type().IsChan() && n.Op() == ir.OLEN {
  6026  		s.Fatalf("cannot inline len(chan)") // must use runtime.chanlen now
  6027  	}
  6028  	if n.X.Type().IsChan() && n.Op() == ir.OCAP {
  6029  		s.Fatalf("cannot inline cap(chan)") // must use runtime.chancap now
  6030  	}
  6031  	if n.X.Type().IsMap() && n.Op() == ir.OCAP {
  6032  		s.Fatalf("cannot inline cap(map)") // cap(map) does not exist
  6033  	}
  6034  	// if n == nil {
  6035  	//   return 0
  6036  	// } else {
  6037  	//   // len, the actual loadType depends
  6038  	//   return int(*((*loadType)n))
  6039  	//   // cap (chan only, not used for now)
  6040  	//   return *(((*int)n)+1)
  6041  	// }
  6042  	lenType := n.Type()
  6043  	nilValue := s.constNil(types.Types[types.TUINTPTR])
  6044  	cmp := s.newValue2(ssa.OpEqPtr, types.Types[types.TBOOL], x, nilValue)
  6045  	b := s.endBlock()
  6046  	b.Kind = ssa.BlockIf
  6047  	b.SetControl(cmp)
  6048  	b.Likely = ssa.BranchUnlikely
  6049  
  6050  	bThen := s.f.NewBlock(ssa.BlockPlain)
  6051  	bElse := s.f.NewBlock(ssa.BlockPlain)
  6052  	bAfter := s.f.NewBlock(ssa.BlockPlain)
  6053  
  6054  	// length/capacity of a nil map/chan is zero
  6055  	b.AddEdgeTo(bThen)
  6056  	s.startBlock(bThen)
  6057  	s.vars[n] = s.zeroVal(lenType)
  6058  	s.endBlock()
  6059  	bThen.AddEdgeTo(bAfter)
  6060  
  6061  	b.AddEdgeTo(bElse)
  6062  	s.startBlock(bElse)
  6063  	switch n.Op() {
  6064  	case ir.OLEN:
  6065  		if n.X.Type().IsMap() {
  6066  			// length is stored in the first word, but needs conversion to int.
  6067  			loadType := reflectdata.MapType().Field(0).Type // uint64
  6068  			load := s.load(loadType, x)
  6069  			s.vars[n] = s.conv(nil, load, loadType, lenType) // integer conversion doesn't need Node
  6070  		} else {
  6071  			// length is stored in the first word for chan, no conversion needed.
  6072  			s.vars[n] = s.load(lenType, x)
  6073  		}
  6074  	case ir.OCAP:
  6075  		// capacity is stored in the second word for chan
  6076  		sw := s.newValue1I(ssa.OpOffPtr, lenType.PtrTo(), lenType.Size(), x)
  6077  		s.vars[n] = s.load(lenType, sw)
  6078  	default:
  6079  		s.Fatalf("op must be OLEN or OCAP")
  6080  	}
  6081  	s.endBlock()
  6082  	bElse.AddEdgeTo(bAfter)
  6083  
  6084  	s.startBlock(bAfter)
  6085  	return s.variable(n, lenType)
  6086  }
  6087  
  6088  type f2uCvtTab struct {
  6089  	ltf, cvt2U, subf, or ssa.Op
  6090  	floatValue           func(*state, *types.Type, float64) *ssa.Value
  6091  	intValue             func(*state, *types.Type, int64) *ssa.Value
  6092  	cutoff               uint64
  6093  }
  6094  
  6095  var f32_u64 = f2uCvtTab{
  6096  	ltf:        ssa.OpLess32F,
  6097  	cvt2U:      ssa.OpCvt32Fto64,
  6098  	subf:       ssa.OpSub32F,
  6099  	or:         ssa.OpOr64,
  6100  	floatValue: (*state).constFloat32,
  6101  	intValue:   (*state).constInt64,
  6102  	cutoff:     1 << 63,
  6103  }
  6104  
  6105  var f64_u64 = f2uCvtTab{
  6106  	ltf:        ssa.OpLess64F,
  6107  	cvt2U:      ssa.OpCvt64Fto64,
  6108  	subf:       ssa.OpSub64F,
  6109  	or:         ssa.OpOr64,
  6110  	floatValue: (*state).constFloat64,
  6111  	intValue:   (*state).constInt64,
  6112  	cutoff:     1 << 63,
  6113  }
  6114  
  6115  var f32_u32 = f2uCvtTab{
  6116  	ltf:        ssa.OpLess32F,
  6117  	cvt2U:      ssa.OpCvt32Fto32,
  6118  	subf:       ssa.OpSub32F,
  6119  	or:         ssa.OpOr32,
  6120  	floatValue: (*state).constFloat32,
  6121  	intValue:   func(s *state, t *types.Type, v int64) *ssa.Value { return s.constInt32(t, int32(v)) },
  6122  	cutoff:     1 << 31,
  6123  }
  6124  
  6125  var f64_u32 = f2uCvtTab{
  6126  	ltf:        ssa.OpLess64F,
  6127  	cvt2U:      ssa.OpCvt64Fto32,
  6128  	subf:       ssa.OpSub64F,
  6129  	or:         ssa.OpOr32,
  6130  	floatValue: (*state).constFloat64,
  6131  	intValue:   func(s *state, t *types.Type, v int64) *ssa.Value { return s.constInt32(t, int32(v)) },
  6132  	cutoff:     1 << 31,
  6133  }
  6134  
  6135  func (s *state) float32ToUint64(n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  6136  	return s.floatToUint(&f32_u64, n, x, ft, tt)
  6137  }
  6138  func (s *state) float64ToUint64(n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  6139  	return s.floatToUint(&f64_u64, n, x, ft, tt)
  6140  }
  6141  
  6142  func (s *state) float32ToUint32(n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  6143  	return s.floatToUint(&f32_u32, n, x, ft, tt)
  6144  }
  6145  
  6146  func (s *state) float64ToUint32(n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  6147  	return s.floatToUint(&f64_u32, n, x, ft, tt)
  6148  }
  6149  
  6150  func (s *state) floatToUint(cvttab *f2uCvtTab, n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  6151  	// cutoff:=1<<(intY_Size-1)
  6152  	// if x < floatX(cutoff) {
  6153  	// 	result = uintY(x) // bThen
  6154  	//  // gated by ConvertHash, clamp negative inputs to zero
  6155  	// 	if x < 0 { // unlikely
  6156  	// 		result = 0 // bZero
  6157  	// 	}
  6158  	// } else {
  6159  	// 	y = x - floatX(cutoff) // bElse
  6160  	// 	z = uintY(y)
  6161  	// 	result = z | -(cutoff)
  6162  	// }
  6163  
  6164  	cutoff := cvttab.floatValue(s, ft, float64(cvttab.cutoff))
  6165  	cmp := s.newValueOrSfCall2(cvttab.ltf, types.Types[types.TBOOL], x, cutoff)
  6166  	b := s.endBlock()
  6167  	b.Kind = ssa.BlockIf
  6168  	b.SetControl(cmp)
  6169  	b.Likely = ssa.BranchLikely
  6170  
  6171  	var bThen, bZero *ssa.Block
  6172  	// use salted hash to distinguish unsigned convert at a Pos from signed convert at a Pos
  6173  	newConversion := base.ConvertHash.MatchPosWithInfo(n.Pos(), "U", nil)
  6174  	if newConversion {
  6175  		bZero = s.f.NewBlock(ssa.BlockPlain)
  6176  		bThen = s.f.NewBlock(ssa.BlockIf)
  6177  	} else {
  6178  		bThen = s.f.NewBlock(ssa.BlockPlain)
  6179  	}
  6180  
  6181  	bElse := s.f.NewBlock(ssa.BlockPlain)
  6182  	bAfter := s.f.NewBlock(ssa.BlockPlain)
  6183  
  6184  	b.AddEdgeTo(bThen)
  6185  	s.startBlock(bThen)
  6186  	a0 := s.newValueOrSfCall1(cvttab.cvt2U, tt, x)
  6187  	s.vars[n] = a0
  6188  
  6189  	if newConversion {
  6190  		cmpz := s.newValueOrSfCall2(cvttab.ltf, types.Types[types.TBOOL], x, cvttab.floatValue(s, ft, 0.0))
  6191  		s.endBlock()
  6192  		bThen.SetControl(cmpz)
  6193  		bThen.AddEdgeTo(bZero)
  6194  		bThen.Likely = ssa.BranchUnlikely
  6195  		bThen.AddEdgeTo(bAfter)
  6196  
  6197  		s.startBlock(bZero)
  6198  		s.vars[n] = cvttab.intValue(s, tt, 0)
  6199  		s.endBlock()
  6200  		bZero.AddEdgeTo(bAfter)
  6201  	} else {
  6202  		s.endBlock()
  6203  		bThen.AddEdgeTo(bAfter)
  6204  	}
  6205  
  6206  	b.AddEdgeTo(bElse)
  6207  	s.startBlock(bElse)
  6208  	y := s.newValueOrSfCall2(cvttab.subf, ft, x, cutoff)
  6209  	y = s.newValueOrSfCall1(cvttab.cvt2U, tt, y)
  6210  	z := cvttab.intValue(s, tt, int64(-cvttab.cutoff))
  6211  	a1 := s.newValue2(cvttab.or, tt, y, z)
  6212  	s.vars[n] = a1
  6213  	s.endBlock()
  6214  	bElse.AddEdgeTo(bAfter)
  6215  
  6216  	s.startBlock(bAfter)
  6217  	return s.variable(n, n.Type())
  6218  }
  6219  
  6220  // dottype generates SSA for a type assertion node.
  6221  // commaok indicates whether to panic or return a bool.
  6222  // If commaok is false, resok will be nil.
  6223  func (s *state) dottype(n *ir.TypeAssertExpr, commaok bool) (res, resok *ssa.Value) {
  6224  	iface := s.expr(n.X)              // input interface
  6225  	target := s.reflectType(n.Type()) // target type
  6226  	var targetItab *ssa.Value
  6227  	if n.ITab != nil {
  6228  		targetItab = s.expr(n.ITab)
  6229  	}
  6230  
  6231  	if n.UseNilPanic {
  6232  		if commaok {
  6233  			base.Fatalf("unexpected *ir.TypeAssertExpr with UseNilPanic == true && commaok == true")
  6234  		}
  6235  		if n.Type().IsInterface() {
  6236  			// Currently we do not expect the compiler to emit type assertions with UseNilPanic, that asserts to an interface type.
  6237  			// If needed, this can be relaxed in the future, but for now we can't assert that.
  6238  			base.Fatalf("unexpected *ir.TypeAssertExpr with UseNilPanic == true && Type().IsInterface() == true")
  6239  		}
  6240  		typs := s.f.Config.Types
  6241  		iface = s.newValue2(
  6242  			ssa.OpIMake,
  6243  			iface.Type,
  6244  			s.nilCheck(s.newValue1(ssa.OpITab, typs.BytePtr, iface)),
  6245  			s.newValue1(ssa.OpIData, typs.BytePtr, iface),
  6246  		)
  6247  	}
  6248  
  6249  	return s.dottype1(n.Pos(), n.X.Type(), n.Type(), iface, nil, target, targetItab, commaok, n.Descriptor)
  6250  }
  6251  
  6252  func (s *state) dynamicDottype(n *ir.DynamicTypeAssertExpr, commaok bool) (res, resok *ssa.Value) {
  6253  	iface := s.expr(n.X)
  6254  	var source, target, targetItab *ssa.Value
  6255  	if n.SrcRType != nil {
  6256  		source = s.expr(n.SrcRType)
  6257  	}
  6258  	if !n.X.Type().IsEmptyInterface() && !n.Type().IsInterface() {
  6259  		byteptr := s.f.Config.Types.BytePtr
  6260  		targetItab = s.expr(n.ITab)
  6261  		// TODO(mdempsky): Investigate whether compiling n.RType could be
  6262  		// better than loading itab.typ.
  6263  		target = s.load(byteptr, s.newValue1I(ssa.OpOffPtr, byteptr, rttype.ITab.OffsetOf("Type"), targetItab))
  6264  	} else {
  6265  		target = s.expr(n.RType)
  6266  	}
  6267  	return s.dottype1(n.Pos(), n.X.Type(), n.Type(), iface, source, target, targetItab, commaok, nil)
  6268  }
  6269  
  6270  // dottype1 implements a x.(T) operation. iface is the argument (x), dst is the type we're asserting to (T)
  6271  // and src is the type we're asserting from.
  6272  // source is the *runtime._type of src
  6273  // target is the *runtime._type of dst.
  6274  // If src is a nonempty interface and dst is not an interface, targetItab is an itab representing (dst, src). Otherwise it is nil.
  6275  // commaok is true if the caller wants a boolean success value. Otherwise, the generated code panics if the conversion fails.
  6276  // descriptor is a compiler-allocated internal/abi.TypeAssert whose address is passed to runtime.typeAssert when
  6277  // the target type is a compile-time-known non-empty interface. It may be nil.
  6278  func (s *state) dottype1(pos src.XPos, src, dst *types.Type, iface, source, target, targetItab *ssa.Value, commaok bool, descriptor *obj.LSym) (res, resok *ssa.Value) {
  6279  	typs := s.f.Config.Types
  6280  	byteptr := typs.BytePtr
  6281  	if dst.IsInterface() {
  6282  		if dst.IsEmptyInterface() {
  6283  			// Converting to an empty interface.
  6284  			// Input could be an empty or nonempty interface.
  6285  			if base.Debug.TypeAssert > 0 {
  6286  				base.WarnfAt(pos, "type assertion inlined")
  6287  			}
  6288  
  6289  			// Get itab/type field from input.
  6290  			itab := s.newValue1(ssa.OpITab, byteptr, iface)
  6291  			// Conversion succeeds iff that field is not nil.
  6292  			cond := s.newValue2(ssa.OpNeqPtr, types.Types[types.TBOOL], itab, s.constNil(byteptr))
  6293  
  6294  			if src.IsEmptyInterface() && commaok {
  6295  				// Converting empty interface to empty interface with ,ok is just a nil check.
  6296  				return iface, cond
  6297  			}
  6298  
  6299  			// Branch on nilness.
  6300  			b := s.endBlock()
  6301  			b.Kind = ssa.BlockIf
  6302  			b.SetControl(cond)
  6303  			b.Likely = ssa.BranchLikely
  6304  			bOk := s.f.NewBlock(ssa.BlockPlain)
  6305  			bFail := s.f.NewBlock(ssa.BlockPlain)
  6306  			b.AddEdgeTo(bOk)
  6307  			b.AddEdgeTo(bFail)
  6308  
  6309  			if !commaok {
  6310  				// On failure, panic by calling panicnildottype.
  6311  				s.startBlock(bFail)
  6312  				s.rtcall(ir.Syms.Panicnildottype, false, nil, target)
  6313  
  6314  				// On success, return (perhaps modified) input interface.
  6315  				s.startBlock(bOk)
  6316  				if src.IsEmptyInterface() {
  6317  					res = iface // Use input interface unchanged.
  6318  					return
  6319  				}
  6320  				// Load type out of itab, build interface with existing idata.
  6321  				off := s.newValue1I(ssa.OpOffPtr, byteptr, rttype.ITab.OffsetOf("Type"), itab)
  6322  				typ := s.load(byteptr, off)
  6323  				idata := s.newValue1(ssa.OpIData, byteptr, iface)
  6324  				res = s.newValue2(ssa.OpIMake, dst, typ, idata)
  6325  				return
  6326  			}
  6327  
  6328  			s.startBlock(bOk)
  6329  			// nonempty -> empty
  6330  			// Need to load type from itab
  6331  			off := s.newValue1I(ssa.OpOffPtr, byteptr, rttype.ITab.OffsetOf("Type"), itab)
  6332  			s.vars[typVar] = s.load(byteptr, off)
  6333  			s.endBlock()
  6334  
  6335  			// itab is nil, might as well use that as the nil result.
  6336  			s.startBlock(bFail)
  6337  			s.vars[typVar] = itab
  6338  			s.endBlock()
  6339  
  6340  			// Merge point.
  6341  			bEnd := s.f.NewBlock(ssa.BlockPlain)
  6342  			bOk.AddEdgeTo(bEnd)
  6343  			bFail.AddEdgeTo(bEnd)
  6344  			s.startBlock(bEnd)
  6345  			idata := s.newValue1(ssa.OpIData, byteptr, iface)
  6346  			res = s.newValue2(ssa.OpIMake, dst, s.variable(typVar, byteptr), idata)
  6347  			resok = cond
  6348  			delete(s.vars, typVar) // no practical effect, just to indicate typVar is no longer live.
  6349  			return
  6350  		}
  6351  		// converting to a nonempty interface needs a runtime call.
  6352  		if base.Debug.TypeAssert > 0 {
  6353  			base.WarnfAt(pos, "type assertion not inlined")
  6354  		}
  6355  
  6356  		itab := s.newValue1(ssa.OpITab, byteptr, iface)
  6357  		data := s.newValue1(ssa.OpIData, types.Types[types.TUNSAFEPTR], iface)
  6358  
  6359  		// First, check for nil.
  6360  		bNil := s.f.NewBlock(ssa.BlockPlain)
  6361  		bNonNil := s.f.NewBlock(ssa.BlockPlain)
  6362  		bMerge := s.f.NewBlock(ssa.BlockPlain)
  6363  		cond := s.newValue2(ssa.OpNeqPtr, types.Types[types.TBOOL], itab, s.constNil(byteptr))
  6364  		b := s.endBlock()
  6365  		b.Kind = ssa.BlockIf
  6366  		b.SetControl(cond)
  6367  		b.Likely = ssa.BranchLikely
  6368  		b.AddEdgeTo(bNonNil)
  6369  		b.AddEdgeTo(bNil)
  6370  
  6371  		s.startBlock(bNil)
  6372  		if commaok {
  6373  			s.vars[typVar] = itab // which will be nil
  6374  			b := s.endBlock()
  6375  			b.AddEdgeTo(bMerge)
  6376  		} else {
  6377  			// Panic if input is nil.
  6378  			s.rtcall(ir.Syms.Panicnildottype, false, nil, target)
  6379  		}
  6380  
  6381  		// Get typ, possibly by loading out of itab.
  6382  		s.startBlock(bNonNil)
  6383  		typ := itab
  6384  		if !src.IsEmptyInterface() {
  6385  			typ = s.load(byteptr, s.newValue1I(ssa.OpOffPtr, byteptr, rttype.ITab.OffsetOf("Type"), itab))
  6386  		}
  6387  
  6388  		// Check the cache first.
  6389  		var d *ssa.Value
  6390  		if descriptor != nil {
  6391  			d = s.newValue1A(ssa.OpAddr, byteptr, descriptor, s.sb)
  6392  			if base.Flag.N == 0 && rtabi.UseInterfaceSwitchCache(Arch.LinkArch.Family) {
  6393  				// Note: we can only use the cache if we have the right atomic load instruction.
  6394  				// Double-check that here.
  6395  				if intrinsics.lookup(Arch.LinkArch.Arch, "internal/runtime/atomic", "Loadp") == nil {
  6396  					s.Fatalf("atomic load not available")
  6397  				}
  6398  				// Pick right size ops.
  6399  				var mul, and, add, zext ssa.Op
  6400  				if s.config.PtrSize == 4 {
  6401  					mul = ssa.OpMul32
  6402  					and = ssa.OpAnd32
  6403  					add = ssa.OpAdd32
  6404  					zext = ssa.OpCopy
  6405  				} else {
  6406  					mul = ssa.OpMul64
  6407  					and = ssa.OpAnd64
  6408  					add = ssa.OpAdd64
  6409  					zext = ssa.OpZeroExt32to64
  6410  				}
  6411  
  6412  				loopHead := s.f.NewBlock(ssa.BlockPlain)
  6413  				loopBody := s.f.NewBlock(ssa.BlockPlain)
  6414  				cacheHit := s.f.NewBlock(ssa.BlockPlain)
  6415  				cacheMiss := s.f.NewBlock(ssa.BlockPlain)
  6416  
  6417  				// Load cache pointer out of descriptor, with an atomic load so
  6418  				// we ensure that we see a fully written cache.
  6419  				atomicLoad := s.newValue2(ssa.OpAtomicLoadPtr, types.NewTuple(typs.BytePtr, types.TypeMem), d, s.mem())
  6420  				cache := s.newValue1(ssa.OpSelect0, typs.BytePtr, atomicLoad)
  6421  				s.vars[memVar] = s.newValue1(ssa.OpSelect1, types.TypeMem, atomicLoad)
  6422  
  6423  				// Load hash from type or itab.
  6424  				var hash *ssa.Value
  6425  				if src.IsEmptyInterface() {
  6426  					hash = s.newValue2(ssa.OpLoad, typs.UInt32, s.newValue1I(ssa.OpOffPtr, typs.UInt32Ptr, rttype.Type.OffsetOf("Hash"), typ), s.mem())
  6427  				} else {
  6428  					hash = s.newValue2(ssa.OpLoad, typs.UInt32, s.newValue1I(ssa.OpOffPtr, typs.UInt32Ptr, rttype.ITab.OffsetOf("Hash"), itab), s.mem())
  6429  				}
  6430  				hash = s.newValue1(zext, typs.Uintptr, hash)
  6431  				s.vars[hashVar] = hash
  6432  				// Load mask from cache.
  6433  				mask := s.newValue2(ssa.OpLoad, typs.Uintptr, cache, s.mem())
  6434  				// Jump to loop head.
  6435  				b := s.endBlock()
  6436  				b.AddEdgeTo(loopHead)
  6437  
  6438  				// At loop head, get pointer to the cache entry.
  6439  				//   e := &cache.Entries[hash&mask]
  6440  				s.startBlock(loopHead)
  6441  				idx := s.newValue2(and, typs.Uintptr, s.variable(hashVar, typs.Uintptr), mask)
  6442  				idx = s.newValue2(mul, typs.Uintptr, idx, s.uintptrConstant(uint64(2*s.config.PtrSize)))
  6443  				idx = s.newValue2(add, typs.Uintptr, idx, s.uintptrConstant(uint64(s.config.PtrSize)))
  6444  				e := s.newValue2(ssa.OpAddPtr, typs.UintptrPtr, cache, idx)
  6445  				//   hash++
  6446  				s.vars[hashVar] = s.newValue2(add, typs.Uintptr, s.variable(hashVar, typs.Uintptr), s.uintptrConstant(1))
  6447  
  6448  				// Look for a cache hit.
  6449  				//   if e.Typ == typ { goto hit }
  6450  				eTyp := s.newValue2(ssa.OpLoad, typs.Uintptr, e, s.mem())
  6451  				cmp1 := s.newValue2(ssa.OpEqPtr, typs.Bool, typ, eTyp)
  6452  				b = s.endBlock()
  6453  				b.Kind = ssa.BlockIf
  6454  				b.SetControl(cmp1)
  6455  				b.AddEdgeTo(cacheHit)
  6456  				b.AddEdgeTo(loopBody)
  6457  
  6458  				// Look for an empty entry, the tombstone for this hash table.
  6459  				//   if e.Typ == nil { goto miss }
  6460  				s.startBlock(loopBody)
  6461  				cmp2 := s.newValue2(ssa.OpEqPtr, typs.Bool, eTyp, s.constNil(typs.BytePtr))
  6462  				b = s.endBlock()
  6463  				b.Kind = ssa.BlockIf
  6464  				b.SetControl(cmp2)
  6465  				b.AddEdgeTo(cacheMiss)
  6466  				b.AddEdgeTo(loopHead)
  6467  
  6468  				// On a hit, load the data fields of the cache entry.
  6469  				//   Itab = e.Itab
  6470  				s.startBlock(cacheHit)
  6471  				eItab := s.newValue2(ssa.OpLoad, typs.BytePtr, s.newValue1I(ssa.OpOffPtr, typs.BytePtrPtr, s.config.PtrSize, e), s.mem())
  6472  				s.vars[typVar] = eItab
  6473  				b = s.endBlock()
  6474  				b.AddEdgeTo(bMerge)
  6475  
  6476  				// On a miss, call into the runtime to get the answer.
  6477  				s.startBlock(cacheMiss)
  6478  			}
  6479  		}
  6480  
  6481  		// Call into runtime to get itab for result.
  6482  		if descriptor != nil {
  6483  			itab = s.rtcall(ir.Syms.TypeAssert, true, []*types.Type{byteptr}, d, typ)[0]
  6484  		} else {
  6485  			var fn *obj.LSym
  6486  			if commaok {
  6487  				fn = ir.Syms.AssertE2I2
  6488  			} else {
  6489  				fn = ir.Syms.AssertE2I
  6490  			}
  6491  			itab = s.rtcall(fn, true, []*types.Type{byteptr}, target, typ)[0]
  6492  		}
  6493  		s.vars[typVar] = itab
  6494  		b = s.endBlock()
  6495  		b.AddEdgeTo(bMerge)
  6496  
  6497  		// Build resulting interface.
  6498  		s.startBlock(bMerge)
  6499  		itab = s.variable(typVar, byteptr)
  6500  		var ok *ssa.Value
  6501  		if commaok {
  6502  			ok = s.newValue2(ssa.OpNeqPtr, types.Types[types.TBOOL], itab, s.constNil(byteptr))
  6503  		}
  6504  		return s.newValue2(ssa.OpIMake, dst, itab, data), ok
  6505  	}
  6506  
  6507  	if base.Debug.TypeAssert > 0 {
  6508  		base.WarnfAt(pos, "type assertion inlined")
  6509  	}
  6510  
  6511  	// Converting to a concrete type.
  6512  	direct := types.IsDirectIface(dst)
  6513  	itab := s.newValue1(ssa.OpITab, byteptr, iface) // type word of interface
  6514  	if base.Debug.TypeAssert > 0 {
  6515  		base.WarnfAt(pos, "type assertion inlined")
  6516  	}
  6517  	var wantedFirstWord *ssa.Value
  6518  	if src.IsEmptyInterface() {
  6519  		// Looking for pointer to target type.
  6520  		wantedFirstWord = target
  6521  	} else {
  6522  		// Looking for pointer to itab for target type and source interface.
  6523  		wantedFirstWord = targetItab
  6524  	}
  6525  
  6526  	var tmp ir.Node     // temporary for use with large types
  6527  	var addr *ssa.Value // address of tmp
  6528  	if commaok && !ssa.CanSSA(dst) {
  6529  		// unSSAable type, use temporary.
  6530  		// TODO: get rid of some of these temporaries.
  6531  		tmp, addr = s.temp(pos, dst)
  6532  	}
  6533  
  6534  	cond := s.newValue2(ssa.OpEqPtr, types.Types[types.TBOOL], itab, wantedFirstWord)
  6535  	b := s.endBlock()
  6536  	b.Kind = ssa.BlockIf
  6537  	b.SetControl(cond)
  6538  	b.Likely = ssa.BranchLikely
  6539  
  6540  	bOk := s.f.NewBlock(ssa.BlockPlain)
  6541  	bFail := s.f.NewBlock(ssa.BlockPlain)
  6542  	b.AddEdgeTo(bOk)
  6543  	b.AddEdgeTo(bFail)
  6544  
  6545  	if !commaok {
  6546  		// on failure, panic by calling panicdottype
  6547  		s.startBlock(bFail)
  6548  		taddr := source
  6549  		if taddr == nil {
  6550  			taddr = s.reflectType(src)
  6551  		}
  6552  		if src.IsEmptyInterface() {
  6553  			s.rtcall(ir.Syms.PanicdottypeE, false, nil, itab, target, taddr)
  6554  		} else {
  6555  			s.rtcall(ir.Syms.PanicdottypeI, false, nil, itab, target, taddr)
  6556  		}
  6557  
  6558  		// on success, return data from interface
  6559  		s.startBlock(bOk)
  6560  		if direct {
  6561  			return s.newValue1(ssa.OpIData, dst, iface), nil
  6562  		}
  6563  		p := s.newValue1(ssa.OpIData, types.NewPtr(dst), iface)
  6564  		return s.load(dst, p), nil
  6565  	}
  6566  
  6567  	// commaok is the more complicated case because we have
  6568  	// a control flow merge point.
  6569  	bEnd := s.f.NewBlock(ssa.BlockPlain)
  6570  	// Note that we need a new valVar each time (unlike okVar where we can
  6571  	// reuse the variable) because it might have a different type every time.
  6572  	valVar := ssaMarker("val")
  6573  
  6574  	// type assertion succeeded
  6575  	s.startBlock(bOk)
  6576  	if tmp == nil {
  6577  		if direct {
  6578  			s.vars[valVar] = s.newValue1(ssa.OpIData, dst, iface)
  6579  		} else {
  6580  			p := s.newValue1(ssa.OpIData, types.NewPtr(dst), iface)
  6581  			s.vars[valVar] = s.load(dst, p)
  6582  		}
  6583  	} else {
  6584  		p := s.newValue1(ssa.OpIData, types.NewPtr(dst), iface)
  6585  		s.move(dst, addr, p)
  6586  	}
  6587  	s.vars[okVar] = s.constBool(true)
  6588  	s.endBlock()
  6589  	bOk.AddEdgeTo(bEnd)
  6590  
  6591  	// type assertion failed
  6592  	s.startBlock(bFail)
  6593  	if tmp == nil {
  6594  		s.vars[valVar] = s.zeroVal(dst)
  6595  	} else {
  6596  		s.zero(dst, addr)
  6597  	}
  6598  	s.vars[okVar] = s.constBool(false)
  6599  	s.endBlock()
  6600  	bFail.AddEdgeTo(bEnd)
  6601  
  6602  	// merge point
  6603  	s.startBlock(bEnd)
  6604  	if tmp == nil {
  6605  		res = s.variable(valVar, dst)
  6606  		delete(s.vars, valVar) // no practical effect, just to indicate typVar is no longer live.
  6607  	} else {
  6608  		res = s.load(dst, addr)
  6609  	}
  6610  	resok = s.variable(okVar, types.Types[types.TBOOL])
  6611  	delete(s.vars, okVar) // ditto
  6612  	return res, resok
  6613  }
  6614  
  6615  // temp allocates a temp of type t at position pos
  6616  func (s *state) temp(pos src.XPos, t *types.Type) (*ir.Name, *ssa.Value) {
  6617  	tmp := typecheck.TempAt(pos, s.curfn, t)
  6618  	if t.HasPointers() || (ssa.IsMergeCandidate(tmp) && t != deferstruct()) {
  6619  		s.vars[memVar] = s.newValue1A(ssa.OpVarDef, types.TypeMem, tmp, s.mem())
  6620  	}
  6621  	addr := s.addr(tmp)
  6622  	return tmp, addr
  6623  }
  6624  
  6625  // variable returns the value of a variable at the current location.
  6626  func (s *state) variable(n ir.Node, t *types.Type) *ssa.Value {
  6627  	v := s.vars[n]
  6628  	if v != nil {
  6629  		return v
  6630  	}
  6631  	v = s.fwdVars[n]
  6632  	if v != nil {
  6633  		return v
  6634  	}
  6635  
  6636  	if s.curBlock == s.f.Entry {
  6637  		// No variable should be live at entry.
  6638  		s.f.Fatalf("value %v (%v) incorrectly live at entry", n, v)
  6639  	}
  6640  	// Make a FwdRef, which records a value that's live on block input.
  6641  	// We'll find the matching definition as part of insertPhis.
  6642  	v = s.newValue0A(ssa.OpFwdRef, t, fwdRefAux{N: n})
  6643  	s.fwdVars[n] = v
  6644  	if n.Op() == ir.ONAME {
  6645  		s.addNamedValue(n.(*ir.Name), v)
  6646  	}
  6647  	return v
  6648  }
  6649  
  6650  func (s *state) mem() *ssa.Value {
  6651  	return s.variable(memVar, types.TypeMem)
  6652  }
  6653  
  6654  func (s *state) addNamedValue(n *ir.Name, v *ssa.Value) {
  6655  	if n.Class == ir.Pxxx {
  6656  		// Don't track our marker nodes (memVar etc.).
  6657  		return
  6658  	}
  6659  	if ir.IsAutoTmp(n) {
  6660  		// Don't track temporary variables.
  6661  		return
  6662  	}
  6663  	if n.Class == ir.PPARAMOUT {
  6664  		// Don't track named output values.  This prevents return values
  6665  		// from being assigned too early. See #14591 and #14762. TODO: allow this.
  6666  		return
  6667  	}
  6668  	loc := ssa.LocalSlot{N: n, Type: n.Type(), Off: 0}
  6669  	values, ok := s.f.NamedValues[loc]
  6670  	if !ok {
  6671  		s.f.Names = append(s.f.Names, &loc)
  6672  		s.f.CanonicalLocalSlots[loc] = &loc
  6673  	}
  6674  	s.f.NamedValues[loc] = append(values, v)
  6675  }
  6676  
  6677  // Branch is an unresolved branch.
  6678  type Branch struct {
  6679  	P *obj.Prog  // branch instruction
  6680  	B *ssa.Block // target
  6681  }
  6682  
  6683  // State contains state needed during Prog generation.
  6684  type State struct {
  6685  	ABI obj.ABI
  6686  
  6687  	pp *objw.Progs
  6688  
  6689  	// Branches remembers all the branch instructions we've seen
  6690  	// and where they would like to go.
  6691  	Branches []Branch
  6692  
  6693  	// JumpTables remembers all the jump tables we've seen.
  6694  	JumpTables []*ssa.Block
  6695  
  6696  	// bstart remembers where each block starts (indexed by block ID)
  6697  	bstart []*obj.Prog
  6698  
  6699  	maxarg int64 // largest frame size for arguments to calls made by the function
  6700  
  6701  	// Map from GC safe points to liveness index, generated by
  6702  	// liveness analysis.
  6703  	livenessMap liveness.Map
  6704  
  6705  	// partLiveArgs includes arguments that may be partially live, for which we
  6706  	// need to generate instructions that spill the argument registers.
  6707  	partLiveArgs map[*ir.Name]bool
  6708  
  6709  	// lineRunStart records the beginning of the current run of instructions
  6710  	// within a single block sharing the same line number
  6711  	// Used to move statement marks to the beginning of such runs.
  6712  	lineRunStart *obj.Prog
  6713  
  6714  	// wasm: The number of values on the WebAssembly stack. This is only used as a safeguard.
  6715  	OnWasmStackSkipped int
  6716  }
  6717  
  6718  func (s *State) FuncInfo() *obj.FuncInfo {
  6719  	return s.pp.CurFunc.LSym.Func()
  6720  }
  6721  
  6722  // Prog appends a new Prog.
  6723  func (s *State) Prog(as obj.As) *obj.Prog {
  6724  	p := s.pp.Prog(as)
  6725  	if objw.LosesStmtMark(as) {
  6726  		return p
  6727  	}
  6728  	// Float a statement start to the beginning of any same-line run.
  6729  	// lineRunStart is reset at block boundaries, which appears to work well.
  6730  	if s.lineRunStart == nil || s.lineRunStart.Pos.Line() != p.Pos.Line() {
  6731  		s.lineRunStart = p
  6732  	} else if p.Pos.IsStmt() == src.PosIsStmt {
  6733  		s.lineRunStart.Pos = s.lineRunStart.Pos.WithIsStmt()
  6734  		p.Pos = p.Pos.WithNotStmt()
  6735  	}
  6736  	return p
  6737  }
  6738  
  6739  // Pc returns the current Prog.
  6740  func (s *State) Pc() *obj.Prog {
  6741  	return s.pp.Next
  6742  }
  6743  
  6744  // SetPos sets the current source position.
  6745  func (s *State) SetPos(pos src.XPos) {
  6746  	s.pp.Pos = pos
  6747  }
  6748  
  6749  // Br emits a single branch instruction and returns the instruction.
  6750  // Not all architectures need the returned instruction, but otherwise
  6751  // the boilerplate is common to all.
  6752  func (s *State) Br(op obj.As, target *ssa.Block) *obj.Prog {
  6753  	p := s.Prog(op)
  6754  	p.To.Type = obj.TYPE_BRANCH
  6755  	s.Branches = append(s.Branches, Branch{P: p, B: target})
  6756  	return p
  6757  }
  6758  
  6759  // DebugFriendlySetPosFrom adjusts Pos.IsStmt subject to heuristics
  6760  // that reduce "jumpy" line number churn when debugging.
  6761  // Spill/fill/copy instructions from the register allocator,
  6762  // phi functions, and instructions with a no-pos position
  6763  // are examples of instructions that can cause churn.
  6764  func (s *State) DebugFriendlySetPosFrom(v *ssa.Value) {
  6765  	switch v.Op {
  6766  	case ssa.OpPhi, ssa.OpCopy, ssa.OpLoadReg, ssa.OpStoreReg:
  6767  		// These are not statements
  6768  		s.SetPos(v.Pos.WithNotStmt())
  6769  	default:
  6770  		p := v.Pos
  6771  		if p != src.NoXPos {
  6772  			// If the position is defined, update the position.
  6773  			// Also convert default IsStmt to NotStmt; only
  6774  			// explicit statement boundaries should appear
  6775  			// in the generated code.
  6776  			if p.IsStmt() != src.PosIsStmt {
  6777  				if s.pp.Pos.IsStmt() == src.PosIsStmt && s.pp.Pos.SameFileAndLine(p) {
  6778  					// If s.pp.Pos already has a statement mark, then it was set here (below) for
  6779  					// the previous value.  If an actual instruction had been emitted for that
  6780  					// value, then the statement mark would have been reset.  Since the statement
  6781  					// mark of s.pp.Pos was not reset, this position (file/line) still needs a
  6782  					// statement mark on an instruction.  If file and line for this value are
  6783  					// the same as the previous value, then the first instruction for this
  6784  					// value will work to take the statement mark.  Return early to avoid
  6785  					// resetting the statement mark.
  6786  					//
  6787  					// The reset of s.pp.Pos occurs in (*Progs).Prog() -- if it emits
  6788  					// an instruction, and the instruction's statement mark was set,
  6789  					// and it is not one of the LosesStmtMark instructions,
  6790  					// then Prog() resets the statement mark on the (*Progs).Pos.
  6791  					return
  6792  				}
  6793  				p = p.WithNotStmt()
  6794  				// Calls use the pos attached to v, but copy the statement mark from State
  6795  			}
  6796  			s.SetPos(p)
  6797  		} else {
  6798  			s.SetPos(s.pp.Pos.WithNotStmt())
  6799  		}
  6800  	}
  6801  }
  6802  
  6803  // emit argument info (locations on stack) for traceback.
  6804  func emitArgInfo(e *ssafn, f *ssa.Func, pp *objw.Progs) {
  6805  	ft := e.curfn.Type()
  6806  	if ft.NumRecvs() == 0 && ft.NumParams() == 0 {
  6807  		return
  6808  	}
  6809  
  6810  	x := EmitArgInfo(e.curfn, f.OwnAux.ABIInfo())
  6811  	x.Set(obj.AttrContentAddressable, true)
  6812  	e.curfn.LSym.Func().ArgInfo = x
  6813  
  6814  	// Emit a funcdata pointing at the arg info data.
  6815  	p := pp.Prog(obj.AFUNCDATA)
  6816  	p.From.SetConst(rtabi.FUNCDATA_ArgInfo)
  6817  	p.To.Type = obj.TYPE_MEM
  6818  	p.To.Name = obj.NAME_EXTERN
  6819  	p.To.Sym = x
  6820  }
  6821  
  6822  // emit argument info (locations on stack) of f for traceback.
  6823  func EmitArgInfo(f *ir.Func, abiInfo *abi.ABIParamResultInfo) *obj.LSym {
  6824  	x := base.Ctxt.Lookup(fmt.Sprintf("%s.arginfo%d", f.LSym.Name, f.ABI))
  6825  	x.Align = 1
  6826  	// NOTE: do not set ContentAddressable here. This may be referenced from
  6827  	// assembly code by name (in this case f is a declaration).
  6828  	// Instead, set it in emitArgInfo above.
  6829  
  6830  	PtrSize := int64(types.PtrSize)
  6831  	uintptrTyp := types.Types[types.TUINTPTR]
  6832  
  6833  	isAggregate := func(t *types.Type) bool {
  6834  		return isStructNotSIMD(t) || t.IsArray() || t.IsComplex() || t.IsInterface() || t.IsString() || t.IsSlice()
  6835  	}
  6836  
  6837  	wOff := 0
  6838  	n := 0
  6839  	writebyte := func(o uint8) { wOff = objw.Uint8(x, wOff, o) }
  6840  
  6841  	// Write one non-aggregate arg/field/element.
  6842  	write1 := func(sz, offset int64) {
  6843  		if offset >= rtabi.TraceArgsSpecial {
  6844  			writebyte(rtabi.TraceArgsOffsetTooLarge)
  6845  		} else {
  6846  			writebyte(uint8(offset))
  6847  			writebyte(uint8(sz))
  6848  		}
  6849  		n++
  6850  	}
  6851  
  6852  	// Visit t recursively and write it out.
  6853  	// Returns whether to continue visiting.
  6854  	var visitType func(baseOffset int64, t *types.Type, depth int) bool
  6855  	visitType = func(baseOffset int64, t *types.Type, depth int) bool {
  6856  		if n >= rtabi.TraceArgsLimit {
  6857  			writebyte(rtabi.TraceArgsDotdotdot)
  6858  			return false
  6859  		}
  6860  		if !isAggregate(t) {
  6861  			write1(t.Size(), baseOffset)
  6862  			return true
  6863  		}
  6864  		writebyte(rtabi.TraceArgsStartAgg)
  6865  		depth++
  6866  		if depth >= rtabi.TraceArgsMaxDepth {
  6867  			writebyte(rtabi.TraceArgsDotdotdot)
  6868  			writebyte(rtabi.TraceArgsEndAgg)
  6869  			n++
  6870  			return true
  6871  		}
  6872  		switch {
  6873  		case t.IsInterface(), t.IsString():
  6874  			_ = visitType(baseOffset, uintptrTyp, depth) &&
  6875  				visitType(baseOffset+PtrSize, uintptrTyp, depth)
  6876  		case t.IsSlice():
  6877  			_ = visitType(baseOffset, uintptrTyp, depth) &&
  6878  				visitType(baseOffset+PtrSize, uintptrTyp, depth) &&
  6879  				visitType(baseOffset+PtrSize*2, uintptrTyp, depth)
  6880  		case t.IsComplex():
  6881  			_ = visitType(baseOffset, types.FloatForComplex(t), depth) &&
  6882  				visitType(baseOffset+t.Size()/2, types.FloatForComplex(t), depth)
  6883  		case t.IsArray():
  6884  			if t.NumElem() == 0 {
  6885  				n++ // {} counts as a component
  6886  				break
  6887  			}
  6888  			for i := int64(0); i < t.NumElem(); i++ {
  6889  				if !visitType(baseOffset, t.Elem(), depth) {
  6890  					break
  6891  				}
  6892  				baseOffset += t.Elem().Size()
  6893  			}
  6894  		case isStructNotSIMD(t):
  6895  			if t.NumFields() == 0 {
  6896  				n++ // {} counts as a component
  6897  				break
  6898  			}
  6899  			for _, field := range t.Fields() {
  6900  				if !visitType(baseOffset+field.Offset, field.Type, depth) {
  6901  					break
  6902  				}
  6903  			}
  6904  		}
  6905  		writebyte(rtabi.TraceArgsEndAgg)
  6906  		return true
  6907  	}
  6908  
  6909  	start := 0
  6910  	if strings.Contains(f.LSym.Name, "[") {
  6911  		// Skip the dictionary argument - it is implicit and the user doesn't need to see it.
  6912  		start = 1
  6913  	}
  6914  
  6915  	for _, a := range abiInfo.InParams()[start:] {
  6916  		if !visitType(a.FrameOffset(abiInfo), a.Type, 0) {
  6917  			break
  6918  		}
  6919  	}
  6920  	writebyte(rtabi.TraceArgsEndSeq)
  6921  	if wOff > rtabi.TraceArgsMaxLen {
  6922  		base.Fatalf("ArgInfo too large")
  6923  	}
  6924  
  6925  	return x
  6926  }
  6927  
  6928  // for wrapper, emit info of wrapped function.
  6929  func emitWrappedFuncInfo(e *ssafn, pp *objw.Progs) {
  6930  	if base.Ctxt.Flag_linkshared {
  6931  		// Relative reference (SymPtrOff) to another shared object doesn't work.
  6932  		// Unfortunate.
  6933  		return
  6934  	}
  6935  
  6936  	wfn := e.curfn.WrappedFunc
  6937  	if wfn == nil {
  6938  		return
  6939  	}
  6940  
  6941  	wsym := wfn.Linksym()
  6942  	x := base.Ctxt.LookupInit(fmt.Sprintf("%s.wrapinfo", wsym.Name), func(x *obj.LSym) {
  6943  		objw.SymPtrOff(x, 0, wsym)
  6944  		x.Set(obj.AttrContentAddressable, true)
  6945  		x.Align = 4
  6946  	})
  6947  	e.curfn.LSym.Func().WrapInfo = x
  6948  
  6949  	// Emit a funcdata pointing at the wrap info data.
  6950  	p := pp.Prog(obj.AFUNCDATA)
  6951  	p.From.SetConst(rtabi.FUNCDATA_WrapInfo)
  6952  	p.To.Type = obj.TYPE_MEM
  6953  	p.To.Name = obj.NAME_EXTERN
  6954  	p.To.Sym = x
  6955  }
  6956  
  6957  // genssa appends entries to pp for each instruction in f.
  6958  func genssa(f *ssa.Func, pp *objw.Progs) {
  6959  	var s State
  6960  	s.ABI = f.OwnAux.Fn.ABI()
  6961  
  6962  	e := f.Frontend().(*ssafn)
  6963  
  6964  	gatherPrintInfo := f.PrintOrHtmlSSA || ssa.GenssaDump[f.Name]
  6965  
  6966  	var lv *liveness.Liveness
  6967  	s.livenessMap, s.partLiveArgs, lv = liveness.Compute(e.curfn, f, e.stkptrsize, pp, gatherPrintInfo)
  6968  	emitArgInfo(e, f, pp)
  6969  	argLiveBlockMap, argLiveValueMap := liveness.ArgLiveness(e.curfn, f, pp)
  6970  
  6971  	openDeferInfo := e.curfn.LSym.Func().OpenCodedDeferInfo
  6972  	if openDeferInfo != nil {
  6973  		// This function uses open-coded defers -- write out the funcdata
  6974  		// info that we computed at the end of genssa.
  6975  		p := pp.Prog(obj.AFUNCDATA)
  6976  		p.From.SetConst(rtabi.FUNCDATA_OpenCodedDeferInfo)
  6977  		p.To.Type = obj.TYPE_MEM
  6978  		p.To.Name = obj.NAME_EXTERN
  6979  		p.To.Sym = openDeferInfo
  6980  	}
  6981  
  6982  	emitWrappedFuncInfo(e, pp)
  6983  
  6984  	// Remember where each block starts.
  6985  	s.bstart = make([]*obj.Prog, f.NumBlocks())
  6986  	s.pp = pp
  6987  	var progToValue map[*obj.Prog]*ssa.Value
  6988  	var progToBlock map[*obj.Prog]*ssa.Block
  6989  	var valueToProgAfter []*obj.Prog // The first Prog following computation of a value v; v is visible at this point.
  6990  	if gatherPrintInfo {
  6991  		progToValue = make(map[*obj.Prog]*ssa.Value, f.NumValues())
  6992  		progToBlock = make(map[*obj.Prog]*ssa.Block, f.NumBlocks())
  6993  		f.Logf("genssa %s\n", f.Name)
  6994  		progToBlock[s.pp.Next] = f.Blocks[0]
  6995  	}
  6996  
  6997  	if base.Ctxt.Flag_locationlists {
  6998  		if cap(f.Cache.ValueToProgAfter) < f.NumValues() {
  6999  			f.Cache.ValueToProgAfter = make([]*obj.Prog, f.NumValues())
  7000  		}
  7001  		valueToProgAfter = f.Cache.ValueToProgAfter[:f.NumValues()]
  7002  		clear(valueToProgAfter)
  7003  	}
  7004  
  7005  	// If the very first instruction is not tagged as a statement,
  7006  	// debuggers may attribute it to previous function in program.
  7007  	firstPos := src.NoXPos
  7008  	for _, v := range f.Entry.Values {
  7009  		if v.Pos.IsStmt() == src.PosIsStmt && v.Op != ssa.OpArg && v.Op != ssa.OpArgIntReg && v.Op != ssa.OpArgFloatReg && v.Op != ssa.OpLoadReg && v.Op != ssa.OpStoreReg {
  7010  			firstPos = v.Pos
  7011  			v.Pos = firstPos.WithDefaultStmt()
  7012  			break
  7013  		}
  7014  	}
  7015  
  7016  	// inlMarks has an entry for each Prog that implements an inline mark.
  7017  	// It maps from that Prog to the global inlining id of the inlined body
  7018  	// which should unwind to this Prog's location.
  7019  	var inlMarks map[*obj.Prog]int32
  7020  	var inlMarkList []*obj.Prog
  7021  
  7022  	// inlMarksByPos maps from a (column 1) source position to the set of
  7023  	// Progs that are in the set above and have that source position.
  7024  	var inlMarksByPos map[src.XPos][]*obj.Prog
  7025  
  7026  	var argLiveIdx int = -1 // argument liveness info index
  7027  
  7028  	// These control cache line alignment; if the required portion of
  7029  	// a cache line is not available, then pad to obtain cache line
  7030  	// alignment.  Not implemented on all architectures, may not be
  7031  	// useful on all architectures.
  7032  	var hotAlign, hotRequire int64
  7033  
  7034  	if base.Debug.AlignHot > 0 {
  7035  		switch base.Ctxt.Arch.Name {
  7036  		// enable this on a case-by-case basis, with benchmarking.
  7037  		// currently shown:
  7038  		//   good for amd64
  7039  		//   not helpful for Apple Silicon
  7040  		//
  7041  		case "amd64", "386":
  7042  			// Align to 64 if 31 or fewer bytes remain in a cache line
  7043  			// benchmarks a little better than always aligning, and also
  7044  			// adds slightly less to the (PGO-compiled) binary size.
  7045  			hotAlign = 64
  7046  			hotRequire = 31
  7047  		}
  7048  	}
  7049  
  7050  	// Emit basic blocks
  7051  	for i, b := range f.Blocks {
  7052  
  7053  		s.lineRunStart = nil
  7054  		s.SetPos(s.pp.Pos.WithNotStmt()) // It needs a non-empty Pos, but cannot be a statement boundary (yet).
  7055  
  7056  		if hotAlign > 0 && b.Hotness&ssa.HotPgoInitial == ssa.HotPgoInitial {
  7057  			// So far this has only been shown profitable for PGO-hot loop headers.
  7058  			// The Hotness values allows distinctions between initial blocks that are "hot" or not, and "flow-in" or not.
  7059  			// Currently only the initial blocks of loops are tagged in this way;
  7060  			// there are no blocks tagged "pgo-hot" that are not also tagged "initial".
  7061  			// TODO more heuristics, more architectures.
  7062  			p := s.pp.Prog(obj.APCALIGNMAX)
  7063  			p.From.SetConst(hotAlign)
  7064  			p.To.SetConst(hotRequire)
  7065  		}
  7066  
  7067  		s.bstart[b.ID] = s.pp.Next
  7068  
  7069  		if idx, ok := argLiveBlockMap[b.ID]; ok && idx != argLiveIdx {
  7070  			argLiveIdx = idx
  7071  			p := s.pp.Prog(obj.APCDATA)
  7072  			p.From.SetConst(rtabi.PCDATA_ArgLiveIndex)
  7073  			p.To.SetConst(int64(idx))
  7074  		}
  7075  
  7076  		// Emit values in block
  7077  		Arch.SSAMarkMoves(&s, b)
  7078  		for _, v := range b.Values {
  7079  			x := s.pp.Next
  7080  			s.DebugFriendlySetPosFrom(v)
  7081  
  7082  			if v.Op.ResultInArg0() && v.ResultReg() != v.Args[0].Reg() {
  7083  				v.Fatalf("input[0] and output not in same register %s", v.LongString())
  7084  			}
  7085  
  7086  			switch v.Op {
  7087  			case ssa.OpInitMem:
  7088  				// memory arg needs no code
  7089  			case ssa.OpArg:
  7090  				// input args need no code
  7091  			case ssa.OpSP, ssa.OpSB:
  7092  				// nothing to do
  7093  			case ssa.OpSelect0, ssa.OpSelect1, ssa.OpSelectN, ssa.OpMakeResult:
  7094  				// nothing to do
  7095  			case ssa.OpGetG:
  7096  				// nothing to do when there's a g register,
  7097  				// and checkLower complains if there's not
  7098  			case ssa.OpVarDef, ssa.OpVarLive, ssa.OpKeepAlive, ssa.OpWBend:
  7099  				// nothing to do; already used by liveness
  7100  			case ssa.OpPhi:
  7101  				CheckLoweredPhi(v)
  7102  			case ssa.OpConvert:
  7103  				// nothing to do; no-op conversion for liveness
  7104  				if v.Args[0].Reg() != v.Reg() {
  7105  					v.Fatalf("OpConvert should be a no-op: %s; %s", v.Args[0].LongString(), v.LongString())
  7106  				}
  7107  			case ssa.OpInlMark:
  7108  				p := Arch.Ginsnop(s.pp)
  7109  				if inlMarks == nil {
  7110  					inlMarks = map[*obj.Prog]int32{}
  7111  					inlMarksByPos = map[src.XPos][]*obj.Prog{}
  7112  				}
  7113  				inlMarks[p] = v.AuxInt32()
  7114  				inlMarkList = append(inlMarkList, p)
  7115  				pos := v.Pos.AtColumn1()
  7116  				inlMarksByPos[pos] = append(inlMarksByPos[pos], p)
  7117  				firstPos = src.NoXPos
  7118  
  7119  			default:
  7120  				// Special case for first line in function; move it to the start (which cannot be a register-valued instruction)
  7121  				if firstPos != src.NoXPos && v.Op != ssa.OpArgIntReg && v.Op != ssa.OpArgFloatReg && v.Op != ssa.OpLoadReg && v.Op != ssa.OpStoreReg {
  7122  					s.SetPos(firstPos)
  7123  					firstPos = src.NoXPos
  7124  				}
  7125  				// Attach this safe point to the next
  7126  				// instruction.
  7127  				s.pp.NextLive = s.livenessMap.Get(v)
  7128  				s.pp.NextUnsafe = s.livenessMap.GetUnsafe(v)
  7129  
  7130  				// let the backend handle it
  7131  				Arch.SSAGenValue(&s, v)
  7132  			}
  7133  
  7134  			if idx, ok := argLiveValueMap[v.ID]; ok && idx != argLiveIdx {
  7135  				argLiveIdx = idx
  7136  				p := s.pp.Prog(obj.APCDATA)
  7137  				p.From.SetConst(rtabi.PCDATA_ArgLiveIndex)
  7138  				p.To.SetConst(int64(idx))
  7139  			}
  7140  
  7141  			if base.Ctxt.Flag_locationlists {
  7142  				valueToProgAfter[v.ID] = s.pp.Next
  7143  			}
  7144  
  7145  			if gatherPrintInfo {
  7146  				for ; x != s.pp.Next; x = x.Link {
  7147  					progToValue[x] = v
  7148  				}
  7149  			}
  7150  		}
  7151  		// If this is an empty infinite loop, stick a hardware NOP in there so that debuggers are less confused.
  7152  		if s.bstart[b.ID] == s.pp.Next && len(b.Succs) == 1 && b.Succs[0].Block() == b {
  7153  			p := Arch.Ginsnop(s.pp)
  7154  			p.Pos = p.Pos.WithIsStmt()
  7155  			if b.Pos == src.NoXPos {
  7156  				b.Pos = p.Pos // It needs a file, otherwise a no-file non-zero line causes confusion.  See #35652.
  7157  				if b.Pos == src.NoXPos {
  7158  					b.Pos = s.pp.Text.Pos // Sometimes p.Pos is empty.  See #35695.
  7159  				}
  7160  			}
  7161  			b.Pos = b.Pos.WithBogusLine() // Debuggers are not good about infinite loops, force a change in line number
  7162  		}
  7163  
  7164  		// Set unsafe mark for any end-of-block generated instructions
  7165  		// (normally, conditional or unconditional branches).
  7166  		// This is particularly important for empty blocks, as there
  7167  		// are no values to inherit the unsafe mark from.
  7168  		s.pp.NextUnsafe = s.livenessMap.GetUnsafeBlock(b)
  7169  
  7170  		// Emit control flow instructions for block
  7171  		var next *ssa.Block
  7172  		if i < len(f.Blocks)-1 && base.Flag.N == 0 {
  7173  			// If -N, leave next==nil so every block with successors
  7174  			// ends in a JMP (except call blocks - plive doesn't like
  7175  			// select{send,recv} followed by a JMP call).  Helps keep
  7176  			// line numbers for otherwise empty blocks.
  7177  			next = f.Blocks[i+1]
  7178  		}
  7179  		x := s.pp.Next
  7180  		s.SetPos(b.Pos)
  7181  		Arch.SSAGenBlock(&s, b, next)
  7182  		if gatherPrintInfo {
  7183  			for ; x != s.pp.Next; x = x.Link {
  7184  				progToBlock[x] = b
  7185  			}
  7186  		}
  7187  	}
  7188  	if f.Blocks[len(f.Blocks)-1].Kind == ssa.BlockExit {
  7189  		// We need the return address of a panic call to
  7190  		// still be inside the function in question. So if
  7191  		// it ends in a call which doesn't return, add a
  7192  		// nop (which will never execute) after the call.
  7193  		Arch.Ginsnop(s.pp)
  7194  	}
  7195  	if openDeferInfo != nil {
  7196  		// When doing open-coded defers, generate a disconnected call to
  7197  		// deferreturn and a return. This will be used to during panic
  7198  		// recovery to unwind the stack and return back to the runtime.
  7199  
  7200  		// Note that this exit code doesn't work if a return parameter
  7201  		// is heap-allocated, but open defers aren't enabled in that case.
  7202  
  7203  		// TODO either make this handle heap-allocated return parameters or reuse the other-defers general-purpose code path.
  7204  		s.pp.NextLive = s.livenessMap.DeferReturn
  7205  		p := s.pp.Prog(obj.ACALL)
  7206  		p.To.Type = obj.TYPE_MEM
  7207  		p.To.Name = obj.NAME_EXTERN
  7208  		p.To.Sym = ir.Syms.Deferreturn
  7209  
  7210  		// Load results into registers. So when a deferred function
  7211  		// recovers a panic, it will return to caller with right results.
  7212  		// The results are already in memory, because they are not SSA'd
  7213  		// when the function has defers (see canSSAName).
  7214  		for _, o := range f.OwnAux.ABIInfo().OutParams() {
  7215  			n := o.Name
  7216  			rts, offs := o.RegisterTypesAndOffsets()
  7217  			for i := range o.Registers {
  7218  				Arch.LoadRegResult(&s, f, rts[i], ssa.ObjRegForAbiReg(o.Registers[i], f.Config), n, offs[i])
  7219  			}
  7220  		}
  7221  
  7222  		s.pp.Prog(obj.ARET)
  7223  	}
  7224  
  7225  	if inlMarks != nil {
  7226  		hasCall := false
  7227  
  7228  		// We have some inline marks. Try to find other instructions we're
  7229  		// going to emit anyway, and use those instructions instead of the
  7230  		// inline marks.
  7231  		for p := s.pp.Text; p != nil; p = p.Link {
  7232  			if p.As == obj.ANOP || p.As == obj.AFUNCDATA || p.As == obj.APCDATA || p.As == obj.ATEXT ||
  7233  				p.As == obj.APCALIGN || p.As == obj.APCALIGNMAX || Arch.LinkArch.Family == sys.Wasm {
  7234  				// Don't use 0-sized instructions as inline marks, because we need
  7235  				// to identify inline mark instructions by pc offset.
  7236  				// (Some of these instructions are sometimes zero-sized, sometimes not.
  7237  				// We must not use anything that even might be zero-sized.)
  7238  				// TODO: are there others?
  7239  				continue
  7240  			}
  7241  			if _, ok := inlMarks[p]; ok {
  7242  				// Don't use inline marks themselves. We don't know
  7243  				// whether they will be zero-sized or not yet.
  7244  				continue
  7245  			}
  7246  			if p.As == obj.ACALL || p.As == obj.ADUFFCOPY || p.As == obj.ADUFFZERO {
  7247  				hasCall = true
  7248  			}
  7249  			pos := p.Pos.AtColumn1()
  7250  			marks := inlMarksByPos[pos]
  7251  			if len(marks) == 0 {
  7252  				continue
  7253  			}
  7254  			for _, m := range marks {
  7255  				// We found an instruction with the same source position as
  7256  				// some of the inline marks.
  7257  				// Use this instruction instead.
  7258  				p.Pos = p.Pos.WithIsStmt() // promote position to a statement
  7259  				s.pp.CurFunc.LSym.Func().AddInlMark(p, inlMarks[m])
  7260  				// Make the inline mark a real nop, so it doesn't generate any code.
  7261  				m.As = obj.ANOP
  7262  				m.Pos = src.NoXPos
  7263  				m.From = obj.Addr{}
  7264  				m.To = obj.Addr{}
  7265  			}
  7266  			delete(inlMarksByPos, pos)
  7267  		}
  7268  		// Any unmatched inline marks now need to be added to the inlining tree (and will generate a nop instruction).
  7269  		for _, p := range inlMarkList {
  7270  			if p.As != obj.ANOP {
  7271  				s.pp.CurFunc.LSym.Func().AddInlMark(p, inlMarks[p])
  7272  			}
  7273  		}
  7274  
  7275  		if e.stksize == 0 && !hasCall {
  7276  			// Frameless leaf function. It doesn't need any preamble,
  7277  			// so make sure its first instruction isn't from an inlined callee.
  7278  			// If it is, add a nop at the start of the function with a position
  7279  			// equal to the start of the function.
  7280  			// This ensures that runtime.FuncForPC(uintptr(reflect.ValueOf(fn).Pointer())).Name()
  7281  			// returns the right answer. See issue 58300.
  7282  			for p := s.pp.Text; p != nil; p = p.Link {
  7283  				if p.As == obj.AFUNCDATA || p.As == obj.APCDATA || p.As == obj.ATEXT || p.As == obj.ANOP {
  7284  					continue
  7285  				}
  7286  				if base.Ctxt.PosTable.Pos(p.Pos).Base().InliningIndex() >= 0 {
  7287  					// Make a real (not 0-sized) nop.
  7288  					nop := Arch.Ginsnop(s.pp)
  7289  					nop.Pos = e.curfn.Pos().WithIsStmt()
  7290  
  7291  					// Unfortunately, Ginsnop puts the instruction at the
  7292  					// end of the list. Move it up to just before p.
  7293  
  7294  					// Unlink from the current list.
  7295  					for x := s.pp.Text; x != nil; x = x.Link {
  7296  						if x.Link == nop {
  7297  							x.Link = nop.Link
  7298  							break
  7299  						}
  7300  					}
  7301  					// Splice in right before p.
  7302  					for x := s.pp.Text; x != nil; x = x.Link {
  7303  						if x.Link == p {
  7304  							nop.Link = p
  7305  							x.Link = nop
  7306  							break
  7307  						}
  7308  					}
  7309  				}
  7310  				break
  7311  			}
  7312  		}
  7313  	}
  7314  
  7315  	if base.Ctxt.Flag_locationlists {
  7316  		var debugInfo *ssa.FuncDebug
  7317  		debugInfo = e.curfn.DebugInfo.(*ssa.FuncDebug)
  7318  		// Save off entry ID in case we need it later for DWARF generation
  7319  		// for return values promoted to the heap.
  7320  		debugInfo.EntryID = f.Entry.ID
  7321  		if e.curfn.ABI == obj.ABIInternal && base.Flag.N != 0 {
  7322  			ssa.BuildFuncDebugNoOptimized(base.Ctxt, f, base.Debug.LocationLists > 1, StackOffset, debugInfo)
  7323  		} else {
  7324  			ssa.BuildFuncDebug(base.Ctxt, f, base.Debug.LocationLists, StackOffset, debugInfo)
  7325  		}
  7326  		bstart := s.bstart
  7327  		idToIdx := make([]int, f.NumBlocks())
  7328  		for i, b := range f.Blocks {
  7329  			idToIdx[b.ID] = i
  7330  		}
  7331  		// Register a callback that will be used later to fill in PCs into location
  7332  		// lists. At the moment, Prog.Pc is a sequence number; it's not a real PC
  7333  		// until after assembly, so the translation needs to be deferred.
  7334  		debugInfo.GetPC = func(b, v ssa.ID) int64 {
  7335  			switch v {
  7336  			case ssa.BlockStart.ID:
  7337  				if b == f.Entry.ID {
  7338  					return 0 // Start at the very beginning, at the assembler-generated prologue.
  7339  					// this should only happen for function args (ssa.OpArg)
  7340  				}
  7341  				return bstart[b].Pc
  7342  			case ssa.BlockEnd.ID:
  7343  				blk := f.Blocks[idToIdx[b]]
  7344  				nv := len(blk.Values)
  7345  				return valueToProgAfter[blk.Values[nv-1].ID].Pc
  7346  			case ssa.FuncEnd.ID:
  7347  				return e.curfn.LSym.Size
  7348  			default:
  7349  				return valueToProgAfter[v].Pc
  7350  			}
  7351  		}
  7352  	}
  7353  
  7354  	// Resolve branches, and relax DefaultStmt into NotStmt
  7355  	for _, br := range s.Branches {
  7356  		br.P.To.SetTarget(s.bstart[br.B.ID])
  7357  		if br.P.Pos.IsStmt() != src.PosIsStmt {
  7358  			br.P.Pos = br.P.Pos.WithNotStmt()
  7359  		} else if v0 := br.B.FirstPossibleStmtValue(); v0 != nil && v0.Pos.Line() == br.P.Pos.Line() && v0.Pos.IsStmt() == src.PosIsStmt {
  7360  			br.P.Pos = br.P.Pos.WithNotStmt()
  7361  		}
  7362  
  7363  	}
  7364  
  7365  	// Resolve jump table destinations.
  7366  	for _, jt := range s.JumpTables {
  7367  		// Convert from *Block targets to *Prog targets.
  7368  		targets := make([]*obj.Prog, len(jt.Succs))
  7369  		for i, e := range jt.Succs {
  7370  			targets[i] = s.bstart[e.Block().ID]
  7371  		}
  7372  		// Add to list of jump tables to be resolved at assembly time.
  7373  		// The assembler converts from *Prog entries to absolute addresses
  7374  		// once it knows instruction byte offsets.
  7375  		fi := s.pp.CurFunc.LSym.Func()
  7376  		fi.JumpTables = append(fi.JumpTables, obj.JumpTable{Sym: jt.Aux.(*obj.LSym), Targets: targets})
  7377  	}
  7378  
  7379  	if e.log { // spew to stdout
  7380  		filename := ""
  7381  		for p := s.pp.Text; p != nil; p = p.Link {
  7382  			if p.Pos.IsKnown() && p.InnermostFilename() != filename {
  7383  				filename = p.InnermostFilename()
  7384  				f.Logf("# %s\n", filename)
  7385  			}
  7386  
  7387  			var s string
  7388  			if v, ok := progToValue[p]; ok {
  7389  				s = v.String()
  7390  			} else if b, ok := progToBlock[p]; ok {
  7391  				s = b.String()
  7392  			} else {
  7393  				s = "   " // most value and branch strings are 2-3 characters long
  7394  			}
  7395  			f.Logf(" %-6s\t%.5d (%s)\t%s\n", s, p.Pc, p.InnermostLineNumber(), p.InstructionString())
  7396  		}
  7397  	}
  7398  	if f.HTMLWriter != nil { // spew to ssa.html
  7399  		var buf strings.Builder
  7400  		buf.WriteString("<code>")
  7401  		buf.WriteString("<dl class=\"ssa-gen\">")
  7402  		filename := ""
  7403  
  7404  		liveness := lv.Format(nil)
  7405  		if liveness != "" {
  7406  			buf.WriteString("<dt class=\"ssa-prog-src\"></dt><dd class=\"ssa-prog\">")
  7407  			buf.WriteString(html.EscapeString("# " + liveness))
  7408  			buf.WriteString("</dd>")
  7409  		}
  7410  
  7411  		for p := s.pp.Text; p != nil; p = p.Link {
  7412  			// Don't spam every line with the file name, which is often huge.
  7413  			// Only print changes, and "unknown" is not a change.
  7414  			if p.Pos.IsKnown() && p.InnermostFilename() != filename {
  7415  				filename = p.InnermostFilename()
  7416  				buf.WriteString("<dt class=\"ssa-prog-src\"></dt><dd class=\"ssa-prog\">")
  7417  				buf.WriteString(html.EscapeString("# " + filename))
  7418  				buf.WriteString("</dd>")
  7419  			}
  7420  
  7421  			buf.WriteString("<dt class=\"ssa-prog-src\">")
  7422  			if v, ok := progToValue[p]; ok {
  7423  
  7424  				// Prefix calls with their liveness, if any
  7425  				if p.As != obj.APCDATA {
  7426  					if liveness := lv.Format(v); liveness != "" {
  7427  						// Steal this line, and restart a line
  7428  						buf.WriteString("</dt><dd class=\"ssa-prog\">")
  7429  						buf.WriteString(html.EscapeString("# " + liveness))
  7430  						buf.WriteString("</dd>")
  7431  						// restarting a line
  7432  						buf.WriteString("<dt class=\"ssa-prog-src\">")
  7433  					}
  7434  				}
  7435  
  7436  				buf.WriteString(v.HTML())
  7437  			} else if b, ok := progToBlock[p]; ok {
  7438  				buf.WriteString("<b>" + b.HTML() + "</b>")
  7439  			}
  7440  			buf.WriteString("</dt>")
  7441  			buf.WriteString("<dd class=\"ssa-prog\">")
  7442  			fmt.Fprintf(&buf, "%.5d <span class=\"l%v line-number\">(%s)</span> %s", p.Pc, p.InnermostLineNumber(), p.InnermostLineNumberHTML(), html.EscapeString(p.InstructionString()))
  7443  			buf.WriteString("</dd>")
  7444  		}
  7445  		buf.WriteString("</dl>")
  7446  		buf.WriteString("</code>")
  7447  		f.HTMLWriter.WriteColumn("genssa", "genssa", "ssa-prog", buf.String())
  7448  	}
  7449  	if ssa.GenssaDump[f.Name] {
  7450  		fi := f.DumpFileForPhase("genssa")
  7451  		if fi != nil {
  7452  
  7453  			// inliningDiffers if any filename changes or if any line number except the innermost (last index) changes.
  7454  			inliningDiffers := func(a, b []src.Pos) bool {
  7455  				if len(a) != len(b) {
  7456  					return true
  7457  				}
  7458  				for i := range a {
  7459  					if a[i].Filename() != b[i].Filename() {
  7460  						return true
  7461  					}
  7462  					if i != len(a)-1 && a[i].Line() != b[i].Line() {
  7463  						return true
  7464  					}
  7465  				}
  7466  				return false
  7467  			}
  7468  
  7469  			var allPosOld []src.Pos
  7470  			var allPos []src.Pos
  7471  
  7472  			for p := s.pp.Text; p != nil; p = p.Link {
  7473  				if p.Pos.IsKnown() {
  7474  					allPos = allPos[:0]
  7475  					p.Ctxt.AllPos(p.Pos, func(pos src.Pos) { allPos = append(allPos, pos) })
  7476  					if inliningDiffers(allPos, allPosOld) {
  7477  						for _, pos := range allPos {
  7478  							fmt.Fprintf(fi, "# %s:%d\n", pos.Filename(), pos.Line())
  7479  						}
  7480  						allPos, allPosOld = allPosOld, allPos // swap, not copy, so that they do not share slice storage.
  7481  					}
  7482  				}
  7483  
  7484  				var s string
  7485  				if v, ok := progToValue[p]; ok {
  7486  					s = v.String()
  7487  				} else if b, ok := progToBlock[p]; ok {
  7488  					s = b.String()
  7489  				} else {
  7490  					s = "   " // most value and branch strings are 2-3 characters long
  7491  				}
  7492  				fmt.Fprintf(fi, " %-6s\t%.5d %s\t%s\n", s, p.Pc, ssa.StmtString(p.Pos), p.InstructionString())
  7493  			}
  7494  			fi.Close()
  7495  		}
  7496  	}
  7497  
  7498  	defframe(&s, e, f)
  7499  
  7500  	f.HTMLWriter.Close()
  7501  	f.HTMLWriter = nil
  7502  }
  7503  
  7504  func defframe(s *State, e *ssafn, f *ssa.Func) {
  7505  	pp := s.pp
  7506  
  7507  	s.maxarg = types.RoundUp(s.maxarg, e.stkalign)
  7508  	frame := s.maxarg + e.stksize
  7509  	if Arch.PadFrame != nil {
  7510  		frame = Arch.PadFrame(frame)
  7511  	}
  7512  
  7513  	// Fill in argument and frame size.
  7514  	pp.Text.To.Type = obj.TYPE_TEXTSIZE
  7515  	pp.Text.To.Val = int32(types.RoundUp(f.OwnAux.ArgWidth(), int64(types.RegSize)))
  7516  	pp.Text.To.Offset = frame
  7517  
  7518  	p := pp.Text
  7519  
  7520  	// Insert code to spill argument registers if the named slot may be partially
  7521  	// live. That is, the named slot is considered live by liveness analysis,
  7522  	// (because a part of it is live), but we may not spill all parts into the
  7523  	// slot. This can only happen with aggregate-typed arguments that are SSA-able
  7524  	// and not address-taken (for non-SSA-able or address-taken arguments we always
  7525  	// spill upfront).
  7526  	// Note: spilling is unnecessary in the -N/no-optimize case, since all values
  7527  	// will be considered non-SSAable and spilled up front.
  7528  	// TODO(register args) Make liveness more fine-grained to that partial spilling is okay.
  7529  	if f.OwnAux.ABIInfo().InRegistersUsed() != 0 && base.Flag.N == 0 {
  7530  		// First, see if it is already spilled before it may be live. Look for a spill
  7531  		// in the entry block up to the first safepoint.
  7532  		type nameOff struct {
  7533  			n   *ir.Name
  7534  			off int64
  7535  		}
  7536  		partLiveArgsSpilled := make(map[nameOff]bool)
  7537  		for _, v := range f.Entry.Values {
  7538  			if v.Op.IsCall() {
  7539  				break
  7540  			}
  7541  			if v.Op != ssa.OpStoreReg || v.Args[0].Op != ssa.OpArgIntReg {
  7542  				continue
  7543  			}
  7544  			n, off := ssa.AutoVar(v)
  7545  			if n.Class != ir.PPARAM || n.Addrtaken() || !ssa.CanSSA(n.Type()) || !s.partLiveArgs[n] {
  7546  				continue
  7547  			}
  7548  			partLiveArgsSpilled[nameOff{n, off}] = true
  7549  		}
  7550  
  7551  		// Then, insert code to spill registers if not already.
  7552  		for _, a := range f.OwnAux.ABIInfo().InParams() {
  7553  			n := a.Name
  7554  			if n == nil || n.Addrtaken() || !ssa.CanSSA(n.Type()) || !s.partLiveArgs[n] || len(a.Registers) <= 1 {
  7555  				continue
  7556  			}
  7557  			rts, offs := a.RegisterTypesAndOffsets()
  7558  			for i := range a.Registers {
  7559  				if !rts[i].HasPointers() {
  7560  					continue
  7561  				}
  7562  				if partLiveArgsSpilled[nameOff{n, offs[i]}] {
  7563  					continue // already spilled
  7564  				}
  7565  				reg := ssa.ObjRegForAbiReg(a.Registers[i], f.Config)
  7566  				p = Arch.SpillArgReg(pp, p, f, rts[i], reg, n, offs[i])
  7567  			}
  7568  		}
  7569  	}
  7570  
  7571  	// Insert code to zero ambiguously live variables so that the
  7572  	// garbage collector only sees initialized values when it
  7573  	// looks for pointers.
  7574  	var lo, hi int64
  7575  
  7576  	// Opaque state for backend to use. Current backends use it to
  7577  	// keep track of which helper registers have been zeroed.
  7578  	var state uint32
  7579  
  7580  	// Iterate through declarations. Autos are sorted in decreasing
  7581  	// frame offset order.
  7582  	for _, n := range e.curfn.Dcl {
  7583  		if !n.Needzero() {
  7584  			continue
  7585  		}
  7586  		if n.Class != ir.PAUTO {
  7587  			e.Fatalf(n.Pos(), "needzero class %d", n.Class)
  7588  		}
  7589  		if n.Type().Size()%int64(types.PtrSize) != 0 || n.FrameOffset()%int64(types.PtrSize) != 0 || n.Type().Size() == 0 {
  7590  			e.Fatalf(n.Pos(), "var %L has size %d offset %d", n, n.Type().Size(), n.Offset_)
  7591  		}
  7592  
  7593  		if lo != hi && n.FrameOffset()+n.Type().Size() >= lo-int64(2*types.RegSize) {
  7594  			// Merge with range we already have.
  7595  			lo = n.FrameOffset()
  7596  			continue
  7597  		}
  7598  
  7599  		// Zero old range
  7600  		p = Arch.ZeroRange(pp, p, frame+lo, hi-lo, &state)
  7601  
  7602  		// Set new range.
  7603  		lo = n.FrameOffset()
  7604  		hi = lo + n.Type().Size()
  7605  	}
  7606  
  7607  	// Zero final range.
  7608  	Arch.ZeroRange(pp, p, frame+lo, hi-lo, &state)
  7609  }
  7610  
  7611  // For generating consecutive jump instructions to model a specific branching
  7612  type IndexJump struct {
  7613  	Jump  obj.As
  7614  	Index int
  7615  }
  7616  
  7617  func (s *State) oneJump(b *ssa.Block, jump *IndexJump) {
  7618  	p := s.Br(jump.Jump, b.Succs[jump.Index].Block())
  7619  	p.Pos = b.Pos
  7620  }
  7621  
  7622  // CombJump generates combinational instructions (2 at present) for a block jump,
  7623  // thereby the behaviour of non-standard condition codes could be simulated
  7624  func (s *State) CombJump(b, next *ssa.Block, jumps *[2][2]IndexJump) {
  7625  	switch next {
  7626  	case b.Succs[0].Block():
  7627  		s.oneJump(b, &jumps[0][0])
  7628  		s.oneJump(b, &jumps[0][1])
  7629  	case b.Succs[1].Block():
  7630  		s.oneJump(b, &jumps[1][0])
  7631  		s.oneJump(b, &jumps[1][1])
  7632  	default:
  7633  		var q *obj.Prog
  7634  		if b.Likely != ssa.BranchUnlikely {
  7635  			s.oneJump(b, &jumps[1][0])
  7636  			s.oneJump(b, &jumps[1][1])
  7637  			q = s.Br(obj.AJMP, b.Succs[1].Block())
  7638  		} else {
  7639  			s.oneJump(b, &jumps[0][0])
  7640  			s.oneJump(b, &jumps[0][1])
  7641  			q = s.Br(obj.AJMP, b.Succs[0].Block())
  7642  		}
  7643  		q.Pos = b.Pos
  7644  	}
  7645  }
  7646  
  7647  // AddAux adds the offset in the aux fields (AuxInt and Aux) of v to a.
  7648  func AddAux(a *obj.Addr, v *ssa.Value) {
  7649  	AddAux2(a, v, v.AuxInt)
  7650  }
  7651  func AddAux2(a *obj.Addr, v *ssa.Value, offset int64) {
  7652  	if a.Type != obj.TYPE_MEM && a.Type != obj.TYPE_ADDR {
  7653  		v.Fatalf("bad AddAux addr %v", a)
  7654  	}
  7655  	// add integer offset
  7656  	a.Offset += offset
  7657  
  7658  	// If no additional symbol offset, we're done.
  7659  	if v.Aux == nil {
  7660  		return
  7661  	}
  7662  	// Add symbol's offset from its base register.
  7663  	switch n := v.Aux.(type) {
  7664  	case *ssa.AuxCall:
  7665  		a.Name = obj.NAME_EXTERN
  7666  		a.Sym = n.Fn
  7667  	case *obj.LSym:
  7668  		a.Name = obj.NAME_EXTERN
  7669  		a.Sym = n
  7670  	case *ir.Name:
  7671  		if n.Class == ir.PPARAM || (n.Class == ir.PPARAMOUT && !n.IsOutputParamInRegisters()) {
  7672  			a.Name = obj.NAME_PARAM
  7673  		} else {
  7674  			a.Name = obj.NAME_AUTO
  7675  		}
  7676  		a.Sym = n.Linksym()
  7677  		a.Offset += n.FrameOffset()
  7678  	default:
  7679  		v.Fatalf("aux in %s not implemented %#v", v, v.Aux)
  7680  	}
  7681  }
  7682  
  7683  // extendIndex extends v to a full int width.
  7684  // panic with the given kind if v does not fit in an int (only on 32-bit archs).
  7685  func (s *state) extendIndex(idx, len *ssa.Value, kind ssa.BoundsKind, bounded bool) *ssa.Value {
  7686  	size := idx.Type.Size()
  7687  	if size == s.config.PtrSize {
  7688  		return idx
  7689  	}
  7690  	if size > s.config.PtrSize {
  7691  		// truncate 64-bit indexes on 32-bit pointer archs. Test the
  7692  		// high word and branch to out-of-bounds failure if it is not 0.
  7693  		var lo *ssa.Value
  7694  		if idx.Type.IsSigned() {
  7695  			lo = s.newValue1(ssa.OpInt64Lo, types.Types[types.TINT], idx)
  7696  		} else {
  7697  			lo = s.newValue1(ssa.OpInt64Lo, types.Types[types.TUINT], idx)
  7698  		}
  7699  		if bounded || base.Flag.B != 0 {
  7700  			return lo
  7701  		}
  7702  		bNext := s.f.NewBlock(ssa.BlockPlain)
  7703  		bPanic := s.f.NewBlock(ssa.BlockExit)
  7704  		hi := s.newValue1(ssa.OpInt64Hi, types.Types[types.TUINT32], idx)
  7705  		cmp := s.newValue2(ssa.OpEq32, types.Types[types.TBOOL], hi, s.constInt32(types.Types[types.TUINT32], 0))
  7706  		if !idx.Type.IsSigned() {
  7707  			switch kind {
  7708  			case ssa.BoundsIndex:
  7709  				kind = ssa.BoundsIndexU
  7710  			case ssa.BoundsSliceAlen:
  7711  				kind = ssa.BoundsSliceAlenU
  7712  			case ssa.BoundsSliceAcap:
  7713  				kind = ssa.BoundsSliceAcapU
  7714  			case ssa.BoundsSliceB:
  7715  				kind = ssa.BoundsSliceBU
  7716  			case ssa.BoundsSlice3Alen:
  7717  				kind = ssa.BoundsSlice3AlenU
  7718  			case ssa.BoundsSlice3Acap:
  7719  				kind = ssa.BoundsSlice3AcapU
  7720  			case ssa.BoundsSlice3B:
  7721  				kind = ssa.BoundsSlice3BU
  7722  			case ssa.BoundsSlice3C:
  7723  				kind = ssa.BoundsSlice3CU
  7724  			}
  7725  		}
  7726  		b := s.endBlock()
  7727  		b.Kind = ssa.BlockIf
  7728  		b.SetControl(cmp)
  7729  		b.Likely = ssa.BranchLikely
  7730  		b.AddEdgeTo(bNext)
  7731  		b.AddEdgeTo(bPanic)
  7732  
  7733  		s.startBlock(bPanic)
  7734  		mem := s.newValue4I(ssa.OpPanicExtend, types.TypeMem, int64(kind), hi, lo, len, s.mem())
  7735  		s.endBlock().SetControl(mem)
  7736  		s.startBlock(bNext)
  7737  
  7738  		return lo
  7739  	}
  7740  
  7741  	// Extend value to the required size
  7742  	var op ssa.Op
  7743  	if idx.Type.IsSigned() {
  7744  		switch 10*size + s.config.PtrSize {
  7745  		case 14:
  7746  			op = ssa.OpSignExt8to32
  7747  		case 18:
  7748  			op = ssa.OpSignExt8to64
  7749  		case 24:
  7750  			op = ssa.OpSignExt16to32
  7751  		case 28:
  7752  			op = ssa.OpSignExt16to64
  7753  		case 48:
  7754  			op = ssa.OpSignExt32to64
  7755  		default:
  7756  			s.Fatalf("bad signed index extension %s", idx.Type)
  7757  		}
  7758  	} else {
  7759  		switch 10*size + s.config.PtrSize {
  7760  		case 14:
  7761  			op = ssa.OpZeroExt8to32
  7762  		case 18:
  7763  			op = ssa.OpZeroExt8to64
  7764  		case 24:
  7765  			op = ssa.OpZeroExt16to32
  7766  		case 28:
  7767  			op = ssa.OpZeroExt16to64
  7768  		case 48:
  7769  			op = ssa.OpZeroExt32to64
  7770  		default:
  7771  			s.Fatalf("bad unsigned index extension %s", idx.Type)
  7772  		}
  7773  	}
  7774  	return s.newValue1(op, types.Types[types.TINT], idx)
  7775  }
  7776  
  7777  // CheckLoweredPhi checks that regalloc and stackalloc correctly handled phi values.
  7778  // Called during ssaGenValue.
  7779  func CheckLoweredPhi(v *ssa.Value) {
  7780  	if v.Op != ssa.OpPhi {
  7781  		v.Fatalf("CheckLoweredPhi called with non-phi value: %v", v.LongString())
  7782  	}
  7783  	if v.Type.IsMemory() {
  7784  		return
  7785  	}
  7786  	f := v.Block.Func
  7787  	loc := f.RegAlloc[v.ID]
  7788  	for _, a := range v.Args {
  7789  		if aloc := f.RegAlloc[a.ID]; aloc != loc { // TODO: .Equal() instead?
  7790  			v.Fatalf("phi arg at different location than phi: %v @ %s, but arg %v @ %s\n%s\n", v, loc, a, aloc, v.Block.Func)
  7791  		}
  7792  	}
  7793  }
  7794  
  7795  // CheckLoweredGetClosurePtr checks that v is the first instruction in the function's entry block,
  7796  // except for incoming in-register arguments.
  7797  // The output of LoweredGetClosurePtr is generally hardwired to the correct register.
  7798  // That register contains the closure pointer on closure entry.
  7799  func CheckLoweredGetClosurePtr(v *ssa.Value) {
  7800  	entry := v.Block.Func.Entry
  7801  	if entry != v.Block {
  7802  		base.Fatalf("in %s, badly placed LoweredGetClosurePtr: %v %v", v.Block.Func.Name, v.Block, v)
  7803  	}
  7804  	for _, w := range entry.Values {
  7805  		if w == v {
  7806  			break
  7807  		}
  7808  		switch w.Op {
  7809  		case ssa.OpArgIntReg, ssa.OpArgFloatReg:
  7810  			// okay
  7811  		default:
  7812  			base.Fatalf("in %s, badly placed LoweredGetClosurePtr: %v %v", v.Block.Func.Name, v.Block, v)
  7813  		}
  7814  	}
  7815  }
  7816  
  7817  // CheckArgReg ensures that v is in the function's entry block.
  7818  func CheckArgReg(v *ssa.Value) {
  7819  	entry := v.Block.Func.Entry
  7820  	if entry != v.Block {
  7821  		base.Fatalf("in %s, badly placed ArgIReg or ArgFReg: %v %v", v.Block.Func.Name, v.Block, v)
  7822  	}
  7823  }
  7824  
  7825  func AddrAuto(a *obj.Addr, v *ssa.Value) {
  7826  	n, off := ssa.AutoVar(v)
  7827  	a.Type = obj.TYPE_MEM
  7828  	a.Sym = n.Linksym()
  7829  	a.Reg = int16(Arch.REGSP)
  7830  	a.Offset = n.FrameOffset() + off
  7831  	if n.Class == ir.PPARAM || (n.Class == ir.PPARAMOUT && !n.IsOutputParamInRegisters()) {
  7832  		a.Name = obj.NAME_PARAM
  7833  	} else {
  7834  		a.Name = obj.NAME_AUTO
  7835  	}
  7836  }
  7837  
  7838  // Call returns a new CALL instruction for the SSA value v.
  7839  // It uses PrepareCall to prepare the call.
  7840  func (s *State) Call(v *ssa.Value) *obj.Prog {
  7841  	pPosIsStmt := s.pp.Pos.IsStmt() // The statement-ness of the call comes from ssaGenState
  7842  	s.PrepareCall(v)
  7843  
  7844  	p := s.Prog(obj.ACALL)
  7845  	if pPosIsStmt == src.PosIsStmt {
  7846  		p.Pos = v.Pos.WithIsStmt()
  7847  	} else {
  7848  		p.Pos = v.Pos.WithNotStmt()
  7849  	}
  7850  	if sym, ok := v.Aux.(*ssa.AuxCall); ok && sym.Fn != nil {
  7851  		p.To.Type = obj.TYPE_MEM
  7852  		p.To.Name = obj.NAME_EXTERN
  7853  		p.To.Sym = sym.Fn
  7854  	} else {
  7855  		// TODO(mdempsky): Can these differences be eliminated?
  7856  		switch Arch.LinkArch.Family {
  7857  		case sys.AMD64, sys.I386, sys.PPC64, sys.RISCV64, sys.S390X, sys.Wasm:
  7858  			p.To.Type = obj.TYPE_REG
  7859  		case sys.ARM, sys.ARM64, sys.Loong64, sys.MIPS, sys.MIPS64:
  7860  			p.To.Type = obj.TYPE_MEM
  7861  		default:
  7862  			base.Fatalf("unknown indirect call family")
  7863  		}
  7864  		p.To.Reg = v.Args[0].Reg()
  7865  	}
  7866  	return p
  7867  }
  7868  
  7869  // TailCall returns a new tail call instruction for the SSA value v.
  7870  // It is like Call, but for a tail call.
  7871  func (s *State) TailCall(v *ssa.Value) *obj.Prog {
  7872  	p := s.Call(v)
  7873  	p.As = obj.ARET
  7874  	return p
  7875  }
  7876  
  7877  // PrepareCall prepares to emit a CALL instruction for v and does call-related bookkeeping.
  7878  // It must be called immediately before emitting the actual CALL instruction,
  7879  // since it emits PCDATA for the stack map at the call (calls are safe points).
  7880  func (s *State) PrepareCall(v *ssa.Value) {
  7881  	idx := s.livenessMap.Get(v)
  7882  	if !idx.StackMapValid() {
  7883  		// See Liveness.hasStackMap.
  7884  		if sym, ok := v.Aux.(*ssa.AuxCall); !ok || !(sym.Fn == ir.Syms.WBZero || sym.Fn == ir.Syms.WBMove) {
  7885  			base.Fatalf("missing stack map index for %v", v.LongString())
  7886  		}
  7887  	}
  7888  
  7889  	call, ok := v.Aux.(*ssa.AuxCall)
  7890  
  7891  	if ok {
  7892  		// Record call graph information for nowritebarrierrec
  7893  		// analysis.
  7894  		if nowritebarrierrecCheck != nil {
  7895  			nowritebarrierrecCheck.recordCall(s.pp.CurFunc, call.Fn, v.Pos)
  7896  		}
  7897  	}
  7898  
  7899  	if s.maxarg < v.AuxInt {
  7900  		s.maxarg = v.AuxInt
  7901  	}
  7902  }
  7903  
  7904  // UseArgs records the fact that an instruction needs a certain amount of
  7905  // callee args space for its use.
  7906  func (s *State) UseArgs(n int64) {
  7907  	if s.maxarg < n {
  7908  		s.maxarg = n
  7909  	}
  7910  }
  7911  
  7912  // fieldIdx finds the index of the field referred to by the ODOT node n.
  7913  func fieldIdx(n *ir.SelectorExpr) int {
  7914  	t := n.X.Type()
  7915  	if !isStructNotSIMD(t) {
  7916  		panic("ODOT's LHS is not a struct")
  7917  	}
  7918  
  7919  	for i, f := range t.Fields() {
  7920  		if f.Sym == n.Sel {
  7921  			if f.Offset != n.Offset() {
  7922  				panic("field offset doesn't match")
  7923  			}
  7924  			return i
  7925  		}
  7926  	}
  7927  	panic(fmt.Sprintf("can't find field in expr %v\n", n))
  7928  
  7929  	// TODO: keep the result of this function somewhere in the ODOT Node
  7930  	// so we don't have to recompute it each time we need it.
  7931  }
  7932  
  7933  // ssafn holds frontend information about a function that the backend is processing.
  7934  // It also exports a bunch of compiler services for the ssa backend.
  7935  type ssafn struct {
  7936  	curfn      *ir.Func
  7937  	strings    map[string]*obj.LSym // map from constant string to data symbols
  7938  	stksize    int64                // stack size for current frame
  7939  	stkptrsize int64                // prefix of stack containing pointers
  7940  
  7941  	// alignment for current frame.
  7942  	// NOTE: when stkalign > PtrSize, currently this only ensures the offsets of
  7943  	// objects in the stack frame are aligned. The stack pointer is still aligned
  7944  	// only PtrSize.
  7945  	stkalign int64
  7946  
  7947  	log bool // print ssa debug to the stdout
  7948  }
  7949  
  7950  // StringData returns a symbol which
  7951  // is the data component of a global string constant containing s.
  7952  func (e *ssafn) StringData(s string) *obj.LSym {
  7953  	if aux, ok := e.strings[s]; ok {
  7954  		return aux
  7955  	}
  7956  	if e.strings == nil {
  7957  		e.strings = make(map[string]*obj.LSym)
  7958  	}
  7959  	data := staticdata.StringSym(e.curfn.Pos(), s)
  7960  	e.strings[s] = data
  7961  	return data
  7962  }
  7963  
  7964  // SplitSlot returns a slot representing the data of parent starting at offset.
  7965  func (e *ssafn) SplitSlot(parent *ssa.LocalSlot, suffix string, offset int64, t *types.Type) ssa.LocalSlot {
  7966  	node := parent.N
  7967  
  7968  	if node.Class != ir.PAUTO || node.Addrtaken() {
  7969  		// addressed things and non-autos retain their parents (i.e., cannot truly be split)
  7970  		return ssa.LocalSlot{N: node, Type: t, Off: parent.Off + offset}
  7971  	}
  7972  
  7973  	sym := &types.Sym{Name: node.Sym().Name + suffix, Pkg: types.LocalPkg}
  7974  	n := e.curfn.NewLocal(parent.N.Pos(), sym, t)
  7975  	n.SetUsed(true)
  7976  	n.SetEsc(ir.EscNever)
  7977  	types.CalcSize(t)
  7978  	return ssa.LocalSlot{N: n, Type: t, Off: 0, SplitOf: parent, SplitOffset: offset}
  7979  }
  7980  
  7981  // Logf logs a message from the compiler.
  7982  func (e *ssafn) Logf(msg string, args ...any) {
  7983  	if e.log {
  7984  		fmt.Printf(msg, args...)
  7985  	}
  7986  }
  7987  
  7988  func (e *ssafn) Log() bool {
  7989  	return e.log
  7990  }
  7991  
  7992  // Fatalf reports a compiler error and exits.
  7993  func (e *ssafn) Fatalf(pos src.XPos, msg string, args ...any) {
  7994  	base.Pos = pos
  7995  	nargs := append([]any{ir.FuncName(e.curfn)}, args...)
  7996  	base.Fatalf("'%s': "+msg, nargs...)
  7997  }
  7998  
  7999  // Warnl reports a "warning", which is usually flag-triggered
  8000  // logging output for the benefit of tests.
  8001  func (e *ssafn) Warnl(pos src.XPos, fmt_ string, args ...any) {
  8002  	base.WarnfAt(pos, fmt_, args...)
  8003  }
  8004  
  8005  func (e *ssafn) Debug_checknil() bool {
  8006  	return base.Debug.Nil != 0
  8007  }
  8008  
  8009  func (e *ssafn) UseWriteBarrier() bool {
  8010  	return base.Flag.WB
  8011  }
  8012  
  8013  func (e *ssafn) Syslook(name string) *obj.LSym {
  8014  	switch name {
  8015  	case "goschedguarded":
  8016  		return ir.Syms.Goschedguarded
  8017  	case "writeBarrier":
  8018  		return ir.Syms.WriteBarrier
  8019  	case "wbZero":
  8020  		return ir.Syms.WBZero
  8021  	case "wbMove":
  8022  		return ir.Syms.WBMove
  8023  	case "cgoCheckMemmove":
  8024  		return ir.Syms.CgoCheckMemmove
  8025  	case "cgoCheckPtrWrite":
  8026  		return ir.Syms.CgoCheckPtrWrite
  8027  	}
  8028  	e.Fatalf(src.NoXPos, "unknown Syslook func %v", name)
  8029  	return nil
  8030  }
  8031  
  8032  func (e *ssafn) Func() *ir.Func {
  8033  	return e.curfn
  8034  }
  8035  
  8036  func clobberBase(n ir.Node) ir.Node {
  8037  	if n.Op() == ir.ODOT {
  8038  		n := n.(*ir.SelectorExpr)
  8039  		if n.X.Type().NumFields() == 1 {
  8040  			return clobberBase(n.X)
  8041  		}
  8042  	}
  8043  	if n.Op() == ir.OINDEX {
  8044  		n := n.(*ir.IndexExpr)
  8045  		if n.X.Type().IsArray() && n.X.Type().NumElem() == 1 {
  8046  			return clobberBase(n.X)
  8047  		}
  8048  	}
  8049  	return n
  8050  }
  8051  
  8052  // callTargetLSym returns the correct LSym to call 'callee' using its ABI.
  8053  func callTargetLSym(callee *ir.Name) *obj.LSym {
  8054  	if callee.Func == nil {
  8055  		// TODO(austin): This happens in case of interface method I.M from imported package.
  8056  		// It's ABIInternal, and would be better if callee.Func was never nil and we didn't
  8057  		// need this case.
  8058  		return callee.Linksym()
  8059  	}
  8060  
  8061  	return callee.LinksymABI(callee.Func.ABI)
  8062  }
  8063  
  8064  // deferStructFnField is the field index of _defer.fn.
  8065  const deferStructFnField = 4
  8066  
  8067  var deferType *types.Type
  8068  
  8069  // deferstruct returns a type interchangeable with runtime._defer.
  8070  // Make sure this stays in sync with runtime/runtime2.go:_defer.
  8071  func deferstruct() *types.Type {
  8072  	if deferType != nil {
  8073  		return deferType
  8074  	}
  8075  
  8076  	makefield := func(name string, t *types.Type) *types.Field {
  8077  		sym := (*types.Pkg)(nil).Lookup(name)
  8078  		return types.NewField(src.NoXPos, sym, t)
  8079  	}
  8080  
  8081  	fields := []*types.Field{
  8082  		makefield("heap", types.Types[types.TBOOL]),
  8083  		makefield("rangefunc", types.Types[types.TBOOL]),
  8084  		makefield("sp", types.Types[types.TUINTPTR]),
  8085  		makefield("pc", types.Types[types.TUINTPTR]),
  8086  		// Note: the types here don't really matter. Defer structures
  8087  		// are always scanned explicitly during stack copying and GC,
  8088  		// so we make them uintptr type even though they are real pointers.
  8089  		makefield("fn", types.Types[types.TUINTPTR]),
  8090  		makefield("link", types.Types[types.TUINTPTR]),
  8091  		makefield("head", types.Types[types.TUINTPTR]),
  8092  	}
  8093  	if name := fields[deferStructFnField].Sym.Name; name != "fn" {
  8094  		base.Fatalf("deferStructFnField is %q, not fn", name)
  8095  	}
  8096  
  8097  	n := ir.NewDeclNameAt(src.NoXPos, ir.OTYPE, ir.Pkgs.Runtime.Lookup("_defer"))
  8098  	typ := types.NewNamed(n)
  8099  	n.SetType(typ)
  8100  	n.SetTypecheck(1)
  8101  
  8102  	// build struct holding the above fields
  8103  	typ.SetUnderlying(types.NewStruct(fields))
  8104  	types.CalcStructSize(typ)
  8105  
  8106  	deferType = typ
  8107  	return typ
  8108  }
  8109  
  8110  // SpillSlotAddr uses LocalSlot information to initialize an obj.Addr
  8111  // The resulting addr is used in a non-standard context -- in the prologue
  8112  // of a function, before the frame has been constructed, so the standard
  8113  // addressing for the parameters will be wrong.
  8114  func SpillSlotAddr(spill ssa.Spill, baseReg int16, extraOffset int64) obj.Addr {
  8115  	return obj.Addr{
  8116  		Name:   obj.NAME_NONE,
  8117  		Type:   obj.TYPE_MEM,
  8118  		Reg:    baseReg,
  8119  		Offset: spill.Offset + extraOffset,
  8120  	}
  8121  }
  8122  
  8123  func isStructNotSIMD(t *types.Type) bool {
  8124  	return t.IsStruct() && !t.IsSIMD()
  8125  }
  8126  
  8127  var BoundsCheckFunc [ssa.BoundsKindCount]*obj.LSym
  8128