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.Op != OpStructMake && data.Op != OpArrayMake1 => data
    84  // Note: the conditional on data.Op ensures that StructMake/ArrayMake1 ops are
    85  // unwrapped before the IMake is thrown away. See issue 77534.
    86  
    87  (Load <t> ptr mem) && t.IsInterface() =>
    88    (IMake
    89      (Load <typ.Uintptr> ptr mem)
    90      (Load <typ.BytePtr>
    91        (OffPtr <typ.BytePtrPtr> [config.PtrSize] ptr)
    92        mem))
    93  (Store dst (IMake itab data) mem) =>
    94    (Store {typ.BytePtr}
    95      (OffPtr <typ.BytePtrPtr> [config.PtrSize] dst)
    96      data
    97      (Store {typ.Uintptr} dst itab mem))
    98  
    99  // Helpers for expand calls
   100  // Some of these are copied from generic.rules
   101  
   102  (IMake _typ (StructMake ___)) => imakeOfStructMake(v)
   103  (StructSelect (IData x)) && v.Type.Size() > 0 => (IData x)
   104  (StructSelect (IData x)) && v.Type.Size() == 0 && v.Type.IsStruct() => (StructMake)
   105  (StructSelect (IData x)) && v.Type.Size() == 0 && v.Type.IsArray() => (ArrayMake0)
   106  
   107  (StructSelect [i] x:(StructMake ___)) => x.Args[i]
   108  
   109  // Special case coming from immediate interface rewriting
   110  // Typical case: (StructSelect [0] (IData (IMake typ dat)) rewrites to (StructSelect [0] dat)
   111  // but because the interface is immediate, the type of "IData" is a one-element struct containing
   112  // a pointer that is not the pointer type of dat (can be a *uint8).
   113  // More annoying case: (ArraySelect[0] (StructSelect[0] isAPtr))
   114  // There, result of the StructSelect is an Array (not a pointer) and
   115  // the pre-rewrite input to the ArraySelect is a struct, not a pointer.
   116  (StructSelect x) && x.Type.IsPtrShaped()  => x
   117  (ArraySelect [0] x) && x.Type.IsPtrShaped()  => x
   118  
   119  // These, too.  Bits is bits.
   120  (ArrayMake1 x) && x.Type.IsPtrShaped() => x
   121  (StructMake x) && x.Type.IsPtrShaped() => x
   122  
   123  
   124  (Store _ (StructMake ___) _) => rewriteStructStore(v)
   125  
   126  (IMake _typ (ArrayMake1 val)) => (IMake _typ val)
   127  (ArraySelect (ArrayMake1 x)) => x
   128  (ArraySelect [0] (IData x)) => (IData x)
   129  
   130  (Store dst (ArrayMake1 e) mem) => (Store {e.Type} dst e mem)
   131  
   132  // NOTE removed must-not-be-SSA condition.
   133  (ArraySelect [i] x:(Load <t> ptr mem)) =>
   134    @x.Block (Load <v.Type> (OffPtr <v.Type.PtrTo()> [t.Elem().Size()*i] ptr) mem)
   135  
   136  (StringPtr x:(Load <t> ptr mem)) && t.IsString() => @x.Block (Load <typ.BytePtr> ptr mem)
   137  (StringLen x:(Load <t> ptr mem)) && t.IsString() => @x.Block (Load <typ.Int>
   138        (OffPtr <typ.IntPtr> [config.PtrSize] ptr)
   139        mem)
   140  
   141  // NOTE removed must-not-be-SSA condition.
   142  (StructSelect [i] x:(Load <t> ptr mem)) =>
   143    @x.Block (Load <v.Type> (OffPtr <v.Type.PtrTo()> [t.FieldOff(int(i))] ptr) mem)
   144  
   145  (ITab x:(Load <t> ptr mem)) && t.IsInterface() => @x.Block (Load <typ.Uintptr> ptr mem)
   146  
   147  (IData x:(Load <t> ptr mem)) && t.IsInterface() => @x.Block (Load <typ.BytePtr>
   148        (OffPtr <typ.BytePtrPtr> [config.PtrSize] ptr)
   149        mem)
   150  
   151  (SlicePtr x:(Load <t> ptr mem)) && t.IsSlice() => @x.Block (Load <t.Elem().PtrTo()> ptr mem)
   152  (SliceLen x:(Load <t> ptr mem)) && t.IsSlice() => @x.Block (Load <typ.Int>
   153        (OffPtr <typ.IntPtr> [config.PtrSize] ptr)
   154        mem)
   155  (SliceCap x:(Load <t> ptr mem)) && t.IsSlice() => @x.Block (Load <typ.Int>
   156        (OffPtr <typ.IntPtr> [2*config.PtrSize] ptr)
   157        mem)
   158  
   159  (ComplexReal x:(Load <t> ptr mem)) && t.IsComplex() && t.Size() == 8 => @x.Block (Load <typ.Float32> ptr mem)
   160  (ComplexImag x:(Load <t> ptr mem)) && t.IsComplex() && t.Size() == 8 => @x.Block (Load <typ.Float32>
   161        (OffPtr <typ.Float32Ptr> [4] ptr)
   162        mem)
   163  
   164  (ComplexReal x:(Load <t> ptr mem)) && t.IsComplex() && t.Size() == 16 => @x.Block (Load <typ.Float64> ptr mem)
   165  (ComplexImag x:(Load <t> ptr mem)) && t.IsComplex() && t.Size() == 16 => @x.Block (Load <typ.Float64>
   166        (OffPtr <typ.Float64Ptr> [8] ptr)
   167        mem)
   168  

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