Text file src/cmd/compile/internal/ssa/_gen/dec.rules

     1  // Copyright 2016 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  // This file contains rules to decompose builtin compound types
     6  // (complex,string,slice,interface) into their constituent
     7  // types.  These rules work together with the decomposeBuiltIn
     8  // pass which handles phis of these types.
     9  
    10  (Store {t} _ _ mem) && t.Size() == 0 => mem
    11  
    12  // complex ops
    13  (ComplexReal (ComplexMake real _  )) => real
    14  (ComplexImag (ComplexMake _ imag )) => imag
    15  
    16  (Load <t> ptr mem) && t.IsComplex() && t.Size() == 8 =>
    17    (ComplexMake
    18      (Load <typ.Float32> ptr mem)
    19      (Load <typ.Float32>
    20        (OffPtr <typ.Float32Ptr> [4] ptr)
    21        mem)
    22      )
    23  (Store {t} dst (ComplexMake real imag) mem) && t.Size() == 8 =>
    24    (Store {typ.Float32}
    25      (OffPtr <typ.Float32Ptr> [4] dst)
    26      imag
    27      (Store {typ.Float32} dst real mem))
    28  (Load <t> ptr mem) && t.IsComplex() && t.Size() == 16 =>
    29    (ComplexMake
    30      (Load <typ.Float64> ptr mem)
    31      (Load <typ.Float64>
    32        (OffPtr <typ.Float64Ptr> [8] ptr)
    33        mem)
    34      )
    35  (Store {t} dst (ComplexMake real imag) mem) && t.Size() == 16 =>
    36    (Store {typ.Float64}
    37      (OffPtr <typ.Float64Ptr> [8] dst)
    38      imag
    39      (Store {typ.Float64} dst real mem))
    40  
    41  // string ops
    42  (StringPtr (StringMake ptr _)) => ptr
    43  (StringLen (StringMake _ len)) => len
    44  
    45  (Load <t> ptr mem) && t.IsString() =>
    46    (StringMake
    47      (Load <typ.BytePtr> ptr mem)
    48      (Load <typ.Int>
    49        (OffPtr <typ.IntPtr> [config.PtrSize] ptr)
    50        mem))
    51  (Store dst (StringMake ptr len) mem) =>
    52    (Store {typ.Int}
    53      (OffPtr <typ.IntPtr> [config.PtrSize] dst)
    54      len
    55      (Store {typ.BytePtr} dst ptr mem))
    56  
    57  // slice ops
    58  (SlicePtr (SliceMake ptr _ _ )) => ptr
    59  (SliceLen (SliceMake _ len _)) => len
    60  (SliceCap (SliceMake _ _ cap)) => cap
    61  (SlicePtrUnchecked (SliceMake ptr _ _ )) => ptr
    62  
    63  (Load <t> ptr mem) && t.IsSlice() =>
    64    (SliceMake
    65      (Load <t.Elem().PtrTo()> ptr mem)
    66      (Load <typ.Int>
    67        (OffPtr <typ.IntPtr> [config.PtrSize] ptr)
    68        mem)
    69      (Load <typ.Int>
    70        (OffPtr <typ.IntPtr> [2*config.PtrSize] ptr)
    71        mem))
    72  (Store {t} dst (SliceMake ptr len cap) mem) =>
    73    (Store {typ.Int}
    74      (OffPtr <typ.IntPtr> [2*config.PtrSize] dst)
    75      cap
    76      (Store {typ.Int}
    77        (OffPtr <typ.IntPtr> [config.PtrSize] dst)
    78        len
    79        (Store {t.Elem().PtrTo()} dst ptr mem)))
    80  
    81  // interface ops
    82  (ITab (IMake itab _)) => itab
    83  (IData (IMake _ data)) => data
    84  
    85  (Load <t> ptr mem) && t.IsInterface() =>
    86    (IMake
    87      (Load <typ.Uintptr> ptr mem)
    88      (Load <typ.BytePtr>
    89        (OffPtr <typ.BytePtrPtr> [config.PtrSize] ptr)
    90        mem))
    91  (Store dst (IMake itab data) mem) =>
    92    (Store {typ.BytePtr}
    93      (OffPtr <typ.BytePtrPtr> [config.PtrSize] dst)
    94      data
    95      (Store {typ.Uintptr} dst itab mem))
    96  
    97  // Helpers for expand calls
    98  // Some of these are copied from generic.rules
    99  
   100  (IMake _typ (StructMake val)) => (IMake _typ val)
   101  (StructSelect [0] (IData x)) => (IData x)
   102  
   103  (StructSelect [i] x:(StructMake ___)) => x.Args[i]
   104  
   105  // Special case coming from immediate interface rewriting
   106  // Typical case: (StructSelect [0] (IData (IMake typ dat)) rewrites to (StructSelect [0] dat)
   107  // but because the interface is immediate, the type of "IData" is a one-element struct containing
   108  // a pointer that is not the pointer type of dat (can be a *uint8).
   109  // More annoying case: (ArraySelect[0] (StructSelect[0] isAPtr))
   110  // There, result of the StructSelect is an Array (not a pointer) and
   111  // the pre-rewrite input to the ArraySelect is a struct, not a pointer.
   112  (StructSelect [0] x) && x.Type.IsPtrShaped()  => x
   113  (ArraySelect [0] x) && x.Type.IsPtrShaped()  => x
   114  
   115  // These, too.  Bits is bits.
   116  (ArrayMake1 x) && x.Type.IsPtrShaped() => x
   117  (StructMake x) && x.Type.IsPtrShaped() => x
   118  
   119  
   120  (Store _ (StructMake ___) _) => rewriteStructStore(v)
   121  
   122  (ArraySelect (ArrayMake1 x)) => x
   123  (ArraySelect [0] (IData x)) => (IData x)
   124  
   125  (Store dst (ArrayMake1 e) mem) => (Store {e.Type} dst e mem)
   126  
   127  // NOTE removed must-not-be-SSA condition.
   128  (ArraySelect [i] x:(Load <t> ptr mem)) =>
   129    @x.Block (Load <v.Type> (OffPtr <v.Type.PtrTo()> [t.Elem().Size()*i] ptr) mem)
   130  
   131  (StringPtr x:(Load <t> ptr mem)) && t.IsString() => @x.Block (Load <typ.BytePtr> ptr mem)
   132  (StringLen x:(Load <t> ptr mem)) && t.IsString() => @x.Block (Load <typ.Int>
   133        (OffPtr <typ.IntPtr> [config.PtrSize] ptr)
   134        mem)
   135  
   136  // NOTE removed must-not-be-SSA condition.
   137  (StructSelect [i] x:(Load <t> ptr mem)) =>
   138    @x.Block (Load <v.Type> (OffPtr <v.Type.PtrTo()> [t.FieldOff(int(i))] ptr) mem)
   139  
   140  (ITab x:(Load <t> ptr mem)) && t.IsInterface() => @x.Block (Load <typ.Uintptr> ptr mem)
   141  
   142  (IData x:(Load <t> ptr mem)) && t.IsInterface() => @x.Block (Load <typ.BytePtr>
   143        (OffPtr <typ.BytePtrPtr> [config.PtrSize] ptr)
   144        mem)
   145  
   146  (SlicePtr x:(Load <t> ptr mem)) && t.IsSlice() => @x.Block (Load <t.Elem().PtrTo()> ptr mem)
   147  (SliceLen x:(Load <t> ptr mem)) && t.IsSlice() => @x.Block (Load <typ.Int>
   148        (OffPtr <typ.IntPtr> [config.PtrSize] ptr)
   149        mem)
   150  (SliceCap x:(Load <t> ptr mem)) && t.IsSlice() => @x.Block (Load <typ.Int>
   151        (OffPtr <typ.IntPtr> [2*config.PtrSize] ptr)
   152        mem)
   153  
   154  (ComplexReal x:(Load <t> ptr mem)) && t.IsComplex() && t.Size() == 8 => @x.Block (Load <typ.Float32> ptr mem)
   155  (ComplexImag x:(Load <t> ptr mem)) && t.IsComplex() && t.Size() == 8 => @x.Block (Load <typ.Float32>
   156        (OffPtr <typ.Float32Ptr> [4] ptr)
   157        mem)
   158  
   159  (ComplexReal x:(Load <t> ptr mem)) && t.IsComplex() && t.Size() == 16 => @x.Block (Load <typ.Float64> ptr mem)
   160  (ComplexImag x:(Load <t> ptr mem)) && t.IsComplex() && t.Size() == 16 => @x.Block (Load <typ.Float64>
   161        (OffPtr <typ.Float64Ptr> [8] ptr)
   162        mem)
   163  

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