blob: 2b3f16c30c251ba3bad9f27dc33884456c6e0dea [file] [log] [blame]
// Copyright 2015 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ssa
import "cmd/compile/internal/types"
// decompose converts phi ops on compound builtin types into phi
// ops on simple types.
// (The remaining compound ops are decomposed with rewrite rules.)
func decomposeBuiltIn(f *Func) {
for _, b := range f.Blocks {
for _, v := range b.Values {
if v.Op != OpPhi {
continue
}
decomposeBuiltInPhi(v)
}
}
// Split up named values into their components.
// NOTE: the component values we are making are dead at this point.
// We must do the opt pass before any deadcode elimination or we will
// lose the name->value correspondence.
var newNames []LocalSlot
for _, name := range f.Names {
t := name.Type
switch {
case t.IsInteger() && t.Size() > f.Config.RegSize:
var elemType *types.Type
if t.IsSigned() {
elemType = f.Config.Types.Int32
} else {
elemType = f.Config.Types.UInt32
}
hiName, loName := f.fe.SplitInt64(name)
newNames = append(newNames, hiName, loName)
for _, v := range f.NamedValues[name] {
hi := v.Block.NewValue1(v.Pos, OpInt64Hi, elemType, v)
lo := v.Block.NewValue1(v.Pos, OpInt64Lo, f.Config.Types.UInt32, v)
f.NamedValues[hiName] = append(f.NamedValues[hiName], hi)
f.NamedValues[loName] = append(f.NamedValues[loName], lo)
}
delete(f.NamedValues, name)
case t.IsComplex():
var elemType *types.Type
if t.Size() == 16 {
elemType = f.Config.Types.Float64
} else {
elemType = f.Config.Types.Float32
}
rName, iName := f.fe.SplitComplex(name)
newNames = append(newNames, rName, iName)
for _, v := range f.NamedValues[name] {
r := v.Block.NewValue1(v.Pos, OpComplexReal, elemType, v)
i := v.Block.NewValue1(v.Pos, OpComplexImag, elemType, v)
f.NamedValues[rName] = append(f.NamedValues[rName], r)
f.NamedValues[iName] = append(f.NamedValues[iName], i)
}
delete(f.NamedValues, name)
case t.IsString():
ptrType := f.Config.Types.BytePtr
lenType := f.Config.Types.Int
ptrName, lenName := f.fe.SplitString(name)
newNames = append(newNames, ptrName, lenName)
for _, v := range f.NamedValues[name] {
ptr := v.Block.NewValue1(v.Pos, OpStringPtr, ptrType, v)
len := v.Block.NewValue1(v.Pos, OpStringLen, lenType, v)
f.NamedValues[ptrName] = append(f.NamedValues[ptrName], ptr)
f.NamedValues[lenName] = append(f.NamedValues[lenName], len)
}
delete(f.NamedValues, name)
case t.IsSlice():
ptrType := f.Config.Types.BytePtr
lenType := f.Config.Types.Int
ptrName, lenName, capName := f.fe.SplitSlice(name)
newNames = append(newNames, ptrName, lenName, capName)
for _, v := range f.NamedValues[name] {
ptr := v.Block.NewValue1(v.Pos, OpSlicePtr, ptrType, v)
len := v.Block.NewValue1(v.Pos, OpSliceLen, lenType, v)
cap := v.Block.NewValue1(v.Pos, OpSliceCap, lenType, v)
f.NamedValues[ptrName] = append(f.NamedValues[ptrName], ptr)
f.NamedValues[lenName] = append(f.NamedValues[lenName], len)
f.NamedValues[capName] = append(f.NamedValues[capName], cap)
}
delete(f.NamedValues, name)
case t.IsInterface():
ptrType := f.Config.Types.BytePtr
typeName, dataName := f.fe.SplitInterface(name)
newNames = append(newNames, typeName, dataName)
for _, v := range f.NamedValues[name] {
typ := v.Block.NewValue1(v.Pos, OpITab, ptrType, v)
data := v.Block.NewValue1(v.Pos, OpIData, ptrType, v)
f.NamedValues[typeName] = append(f.NamedValues[typeName], typ)
f.NamedValues[dataName] = append(f.NamedValues[dataName], data)
}
delete(f.NamedValues, name)
case t.IsFloat():
// floats are never decomposed, even ones bigger than RegSize
case t.Size() > f.Config.RegSize:
f.Fatalf("undecomposed named type %v %v", name, t)
default:
newNames = append(newNames, name)
}
}
f.Names = newNames
}
func decomposeBuiltInPhi(v *Value) {
switch {
case v.Type.IsInteger() && v.Type.Size() > v.Block.Func.Config.RegSize:
decomposeInt64Phi(v)
case v.Type.IsComplex():
decomposeComplexPhi(v)
case v.Type.IsString():
decomposeStringPhi(v)
case v.Type.IsSlice():
decomposeSlicePhi(v)
case v.Type.IsInterface():
decomposeInterfacePhi(v)
case v.Type.IsFloat():
// floats are never decomposed, even ones bigger than RegSize
case v.Type.Size() > v.Block.Func.Config.RegSize:
v.Fatalf("undecomposed type %s", v.Type)
}
}
func decomposeStringPhi(v *Value) {
types := &v.Block.Func.Config.Types
ptrType := types.BytePtr
lenType := types.Int
ptr := v.Block.NewValue0(v.Pos, OpPhi, ptrType)
len := v.Block.NewValue0(v.Pos, OpPhi, lenType)
for _, a := range v.Args {
ptr.AddArg(a.Block.NewValue1(v.Pos, OpStringPtr, ptrType, a))
len.AddArg(a.Block.NewValue1(v.Pos, OpStringLen, lenType, a))
}
v.reset(OpStringMake)
v.AddArg(ptr)
v.AddArg(len)
}
func decomposeSlicePhi(v *Value) {
types := &v.Block.Func.Config.Types
ptrType := types.BytePtr
lenType := types.Int
ptr := v.Block.NewValue0(v.Pos, OpPhi, ptrType)
len := v.Block.NewValue0(v.Pos, OpPhi, lenType)
cap := v.Block.NewValue0(v.Pos, OpPhi, lenType)
for _, a := range v.Args {
ptr.AddArg(a.Block.NewValue1(v.Pos, OpSlicePtr, ptrType, a))
len.AddArg(a.Block.NewValue1(v.Pos, OpSliceLen, lenType, a))
cap.AddArg(a.Block.NewValue1(v.Pos, OpSliceCap, lenType, a))
}
v.reset(OpSliceMake)
v.AddArg(ptr)
v.AddArg(len)
v.AddArg(cap)
}
func decomposeInt64Phi(v *Value) {
cfgtypes := &v.Block.Func.Config.Types
var partType *types.Type
if v.Type.IsSigned() {
partType = cfgtypes.Int32
} else {
partType = cfgtypes.UInt32
}
hi := v.Block.NewValue0(v.Pos, OpPhi, partType)
lo := v.Block.NewValue0(v.Pos, OpPhi, cfgtypes.UInt32)
for _, a := range v.Args {
hi.AddArg(a.Block.NewValue1(v.Pos, OpInt64Hi, partType, a))
lo.AddArg(a.Block.NewValue1(v.Pos, OpInt64Lo, cfgtypes.UInt32, a))
}
v.reset(OpInt64Make)
v.AddArg(hi)
v.AddArg(lo)
}
func decomposeComplexPhi(v *Value) {
cfgtypes := &v.Block.Func.Config.Types
var partType *types.Type
switch z := v.Type.Size(); z {
case 8:
partType = cfgtypes.Float32
case 16:
partType = cfgtypes.Float64
default:
v.Fatalf("decomposeComplexPhi: bad complex size %d", z)
}
real := v.Block.NewValue0(v.Pos, OpPhi, partType)
imag := v.Block.NewValue0(v.Pos, OpPhi, partType)
for _, a := range v.Args {
real.AddArg(a.Block.NewValue1(v.Pos, OpComplexReal, partType, a))
imag.AddArg(a.Block.NewValue1(v.Pos, OpComplexImag, partType, a))
}
v.reset(OpComplexMake)
v.AddArg(real)
v.AddArg(imag)
}
func decomposeInterfacePhi(v *Value) {
ptrType := v.Block.Func.Config.Types.BytePtr
itab := v.Block.NewValue0(v.Pos, OpPhi, ptrType)
data := v.Block.NewValue0(v.Pos, OpPhi, ptrType)
for _, a := range v.Args {
itab.AddArg(a.Block.NewValue1(v.Pos, OpITab, ptrType, a))
data.AddArg(a.Block.NewValue1(v.Pos, OpIData, ptrType, a))
}
v.reset(OpIMake)
v.AddArg(itab)
v.AddArg(data)
}
func decomposeUser(f *Func) {
for _, b := range f.Blocks {
for _, v := range b.Values {
if v.Op != OpPhi {
continue
}
decomposeUserPhi(v)
}
}
// Split up named values into their components.
// NOTE: the component values we are making are dead at this point.
// We must do the opt pass before any deadcode elimination or we will
// lose the name->value correspondence.
i := 0
var fnames []LocalSlot
var newNames []LocalSlot
for _, name := range f.Names {
t := name.Type
switch {
case t.IsStruct():
n := t.NumFields()
fnames = fnames[:0]
for i := 0; i < n; i++ {
fnames = append(fnames, f.fe.SplitStruct(name, i))
}
for _, v := range f.NamedValues[name] {
for i := 0; i < n; i++ {
x := v.Block.NewValue1I(v.Pos, OpStructSelect, t.FieldType(i), int64(i), v)
f.NamedValues[fnames[i]] = append(f.NamedValues[fnames[i]], x)
}
}
delete(f.NamedValues, name)
newNames = append(newNames, fnames...)
case t.IsArray():
if t.NumElem() == 0 {
// TODO(khr): Not sure what to do here. Probably nothing.
// Names for empty arrays aren't important.
break
}
if t.NumElem() != 1 {
f.Fatalf("array not of size 1")
}
elemName := f.fe.SplitArray(name)
for _, v := range f.NamedValues[name] {
e := v.Block.NewValue1I(v.Pos, OpArraySelect, t.ElemType(), 0, v)
f.NamedValues[elemName] = append(f.NamedValues[elemName], e)
}
default:
f.Names[i] = name
i++
}
}
f.Names = f.Names[:i]
f.Names = append(f.Names, newNames...)
}
func decomposeUserPhi(v *Value) {
switch {
case v.Type.IsStruct():
decomposeStructPhi(v)
case v.Type.IsArray():
decomposeArrayPhi(v)
}
}
// decomposeStructPhi replaces phi-of-struct with structmake(phi-for-each-field),
// and then recursively decomposes the phis for each field.
func decomposeStructPhi(v *Value) {
t := v.Type
n := t.NumFields()
var fields [MaxStruct]*Value
for i := 0; i < n; i++ {
fields[i] = v.Block.NewValue0(v.Pos, OpPhi, t.FieldType(i))
}
for _, a := range v.Args {
for i := 0; i < n; i++ {
fields[i].AddArg(a.Block.NewValue1I(v.Pos, OpStructSelect, t.FieldType(i), int64(i), a))
}
}
v.reset(StructMakeOp(n))
v.AddArgs(fields[:n]...)
// Recursively decompose phis for each field.
for _, f := range fields[:n] {
decomposeUserPhi(f)
}
}
// decomposeArrayPhi replaces phi-of-array with arraymake(phi-of-array-element),
// and then recursively decomposes the element phi.
func decomposeArrayPhi(v *Value) {
t := v.Type
if t.NumElem() == 0 {
v.reset(OpArrayMake0)
return
}
if t.NumElem() != 1 {
v.Fatalf("SSAable array must have no more than 1 element")
}
elem := v.Block.NewValue0(v.Pos, OpPhi, t.ElemType())
for _, a := range v.Args {
elem.AddArg(a.Block.NewValue1I(v.Pos, OpArraySelect, t.ElemType(), 0, a))
}
v.reset(OpArrayMake1)
v.AddArg(elem)
// Recursively decompose elem phi.
decomposeUserPhi(elem)
}
// MaxStruct is the maximum number of fields a struct
// can have and still be SSAable.
const MaxStruct = 4
// StructMakeOp returns the opcode to construct a struct with the
// given number of fields.
func StructMakeOp(nf int) Op {
switch nf {
case 0:
return OpStructMake0
case 1:
return OpStructMake1
case 2:
return OpStructMake2
case 3:
return OpStructMake3
case 4:
return OpStructMake4
}
panic("too many fields in an SSAable struct")
}