Adding upstream version 1.16.10.upstream/1.16.10upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 449 insertions, 0 deletions

diff --git a/src/cmd/compile/internal/ssa/decompose.go b/src/cmd/compile/internal/ssa/decompose.go
new file mode 100644
index 0000000..bf7f1e8
--- /dev/null
+++ b/src/cmd/compile/internal/ssa/decompose.go
@@ -0,0 +1,449 @@
+// 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"
+	"sort"
+)
+
+// decompose converts phi ops on compound builtin types into phi
+// ops on simple types, then invokes rewrite rules to decompose
+// other ops on those types.
+func decomposeBuiltIn(f *Func) {
+	// Decompose phis
+	for _, b := range f.Blocks {
+		for _, v := range b.Values {
+			if v.Op != OpPhi {
+				continue
+			}
+			decomposeBuiltInPhi(v)
+		}
+	}
+
+	// Decompose other values
+	// Note: deadcode is false because we need to keep the original
+	// values around so the name component resolution below can still work.
+	applyRewrite(f, rewriteBlockdec, rewriteValuedec, leaveDeadValues)
+	if f.Config.RegSize == 4 {
+		applyRewrite(f, rewriteBlockdec64, rewriteValuedec64, leaveDeadValues)
+	}
+
+	// Split up named values into their components.
+	// accumulate old names for aggregates (that are decomposed) in toDelete for efficient bulk deletion,
+	// accumulate new LocalSlots in newNames for addition after the iteration.  This decomposition is for
+	// builtin types with leaf components, and thus there is no need to reprocess the newly create LocalSlots.
+	var toDelete []namedVal
+	var newNames []LocalSlot
+	for i, name := range f.Names {
+		t := name.Type
+		switch {
+		case t.IsInteger() && t.Size() > f.Config.RegSize:
+			hiName, loName := f.fe.SplitInt64(name)
+			newNames = append(newNames, hiName, loName)
+			for j, v := range f.NamedValues[name] {
+				if v.Op != OpInt64Make {
+					continue
+				}
+				f.NamedValues[hiName] = append(f.NamedValues[hiName], v.Args[0])
+				f.NamedValues[loName] = append(f.NamedValues[loName], v.Args[1])
+				toDelete = append(toDelete, namedVal{i, j})
+			}
+		case t.IsComplex():
+			rName, iName := f.fe.SplitComplex(name)
+			newNames = append(newNames, rName, iName)
+			for j, v := range f.NamedValues[name] {
+				if v.Op != OpComplexMake {
+					continue
+				}
+				f.NamedValues[rName] = append(f.NamedValues[rName], v.Args[0])
+				f.NamedValues[iName] = append(f.NamedValues[iName], v.Args[1])
+				toDelete = append(toDelete, namedVal{i, j})
+			}
+		case t.IsString():
+			ptrName, lenName := f.fe.SplitString(name)
+			newNames = append(newNames, ptrName, lenName)
+			for j, v := range f.NamedValues[name] {
+				if v.Op != OpStringMake {
+					continue
+				}
+				f.NamedValues[ptrName] = append(f.NamedValues[ptrName], v.Args[0])
+				f.NamedValues[lenName] = append(f.NamedValues[lenName], v.Args[1])
+				toDelete = append(toDelete, namedVal{i, j})
+			}
+		case t.IsSlice():
+			ptrName, lenName, capName := f.fe.SplitSlice(name)
+			newNames = append(newNames, ptrName, lenName, capName)
+			for j, v := range f.NamedValues[name] {
+				if v.Op != OpSliceMake {
+					continue
+				}
+				f.NamedValues[ptrName] = append(f.NamedValues[ptrName], v.Args[0])
+				f.NamedValues[lenName] = append(f.NamedValues[lenName], v.Args[1])
+				f.NamedValues[capName] = append(f.NamedValues[capName], v.Args[2])
+				toDelete = append(toDelete, namedVal{i, j})
+			}
+		case t.IsInterface():
+			typeName, dataName := f.fe.SplitInterface(name)
+			newNames = append(newNames, typeName, dataName)
+			for j, v := range f.NamedValues[name] {
+				if v.Op != OpIMake {
+					continue
+				}
+				f.NamedValues[typeName] = append(f.NamedValues[typeName], v.Args[0])
+				f.NamedValues[dataName] = append(f.NamedValues[dataName], v.Args[1])
+				toDelete = append(toDelete, namedVal{i, j})
+			}
+		case t.IsFloat():
+			// floats are never decomposed, even ones bigger than RegSize
+		case t.Size() > f.Config.RegSize:
+			f.Fatalf("undecomposed named type %s %v", name, t)
+		}
+	}
+
+	deleteNamedVals(f, toDelete)
+	f.Names = append(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 := v.Type.Elem().PtrTo()
+	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) {
+	uintptrType := v.Block.Func.Config.Types.Uintptr
+	ptrType := v.Block.Func.Config.Types.BytePtr
+
+	itab := v.Block.NewValue0(v.Pos, OpPhi, uintptrType)
+	data := v.Block.NewValue0(v.Pos, OpPhi, ptrType)
+	for _, a := range v.Args {
+		itab.AddArg(a.Block.NewValue1(v.Pos, OpITab, uintptrType, a))
+		data.AddArg(a.Block.NewValue1(v.Pos, OpIData, ptrType, a))
+	}
+	v.reset(OpIMake)
+	v.AddArg(itab)
+	v.AddArg(data)
+}
+
+func decomposeArgs(f *Func) {
+	applyRewrite(f, rewriteBlockdecArgs, rewriteValuedecArgs, removeDeadValues)
+}
+
+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.
+	i := 0
+	var newNames []LocalSlot
+	for _, name := range f.Names {
+		t := name.Type
+		switch {
+		case t.IsStruct():
+			newNames = decomposeUserStructInto(f, name, newNames)
+		case t.IsArray():
+			newNames = decomposeUserArrayInto(f, name, newNames)
+		default:
+			f.Names[i] = name
+			i++
+		}
+	}
+	f.Names = f.Names[:i]
+	f.Names = append(f.Names, newNames...)
+}
+
+// decomposeUserArrayInto creates names for the element(s) of arrays referenced
+// by name where possible, and appends those new names to slots, which is then
+// returned.
+func decomposeUserArrayInto(f *Func, name LocalSlot, slots []LocalSlot) []LocalSlot {
+	t := name.Type
+	if t.NumElem() == 0 {
+		// TODO(khr): Not sure what to do here.  Probably nothing.
+		// Names for empty arrays aren't important.
+		return slots
+	}
+	if t.NumElem() != 1 {
+		// shouldn't get here due to CanSSA
+		f.Fatalf("array not of size 1")
+	}
+	elemName := f.fe.SplitArray(name)
+	var keep []*Value
+	for _, v := range f.NamedValues[name] {
+		if v.Op != OpArrayMake1 {
+			keep = append(keep, v)
+			continue
+		}
+		f.NamedValues[elemName] = append(f.NamedValues[elemName], v.Args[0])
+	}
+	if len(keep) == 0 {
+		// delete the name for the array as a whole
+		delete(f.NamedValues, name)
+	} else {
+		f.NamedValues[name] = keep
+	}
+
+	if t.Elem().IsArray() {
+		return decomposeUserArrayInto(f, elemName, slots)
+	} else if t.Elem().IsStruct() {
+		return decomposeUserStructInto(f, elemName, slots)
+	}
+
+	return append(slots, elemName)
+}
+
+// decomposeUserStructInto creates names for the fields(s) of structs referenced
+// by name where possible, and appends those new names to slots, which is then
+// returned.
+func decomposeUserStructInto(f *Func, name LocalSlot, slots []LocalSlot) []LocalSlot {
+	fnames := []LocalSlot{} // slots for struct in name
+	t := name.Type
+	n := t.NumFields()
+
+	for i := 0; i < n; i++ {
+		fs := f.fe.SplitStruct(name, i)
+		fnames = append(fnames, fs)
+		// arrays and structs will be decomposed further, so
+		// there's no need to record a name
+		if !fs.Type.IsArray() && !fs.Type.IsStruct() {
+			slots = append(slots, fs)
+		}
+	}
+
+	makeOp := StructMakeOp(n)
+	var keep []*Value
+	// create named values for each struct field
+	for _, v := range f.NamedValues[name] {
+		if v.Op != makeOp {
+			keep = append(keep, v)
+			continue
+		}
+		for i := 0; i < len(fnames); i++ {
+			f.NamedValues[fnames[i]] = append(f.NamedValues[fnames[i]], v.Args[i])
+		}
+	}
+	if len(keep) == 0 {
+		// delete the name for the struct as a whole
+		delete(f.NamedValues, name)
+	} else {
+		f.NamedValues[name] = keep
+	}
+
+	// now that this f.NamedValues contains values for the struct
+	// fields, recurse into nested structs
+	for i := 0; i < n; i++ {
+		if name.Type.FieldType(i).IsStruct() {
+			slots = decomposeUserStructInto(f, fnames[i], slots)
+			delete(f.NamedValues, fnames[i])
+		} else if name.Type.FieldType(i).IsArray() {
+			slots = decomposeUserArrayInto(f, fnames[i], slots)
+			delete(f.NamedValues, fnames[i])
+		}
+	}
+	return slots
+}
+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.Elem())
+	for _, a := range v.Args {
+		elem.AddArg(a.Block.NewValue1I(v.Pos, OpArraySelect, t.Elem(), 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")
+}
+
+type namedVal struct {
+	locIndex, valIndex int // f.NamedValues[f.Names[locIndex]][valIndex] = key
+}
+
+// deleteNamedVals removes particular values with debugger names from f's naming data structures
+func deleteNamedVals(f *Func, toDelete []namedVal) {
+	// Arrange to delete from larger indices to smaller, to ensure swap-with-end deletion does not invalid pending indices.
+	sort.Slice(toDelete, func(i, j int) bool {
+		if toDelete[i].locIndex != toDelete[j].locIndex {
+			return toDelete[i].locIndex > toDelete[j].locIndex
+		}
+		return toDelete[i].valIndex > toDelete[j].valIndex
+
+	})
+
+	// Get rid of obsolete names
+	for _, d := range toDelete {
+		loc := f.Names[d.locIndex]
+		vals := f.NamedValues[loc]
+		l := len(vals) - 1
+		if l > 0 {
+			vals[d.valIndex] = vals[l]
+			f.NamedValues[loc] = vals[:l]
+		} else {
+			delete(f.NamedValues, loc)
+			l = len(f.Names) - 1
+			f.Names[d.locIndex] = f.Names[l]
+			f.Names = f.Names[:l]
+		}
+	}
+}