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path: root/src/cmd/compile/internal/ssa/decompose.go
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Diffstat (limited to 'src/cmd/compile/internal/ssa/decompose.go')
-rw-r--r--src/cmd/compile/internal/ssa/decompose.go87
1 files changed, 67 insertions, 20 deletions
diff --git a/src/cmd/compile/internal/ssa/decompose.go b/src/cmd/compile/internal/ssa/decompose.go
index ab27ba85ae..bf7f1e826b 100644
--- a/src/cmd/compile/internal/ssa/decompose.go
+++ b/src/cmd/compile/internal/ssa/decompose.go
@@ -6,6 +6,7 @@ package ssa
import (
"cmd/compile/internal/types"
+ "sort"
)
// decompose converts phi ops on compound builtin types into phi
@@ -31,77 +32,79 @@ func decomposeBuiltIn(f *Func) {
}
// 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 _, name := range f.Names {
+ 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 _, v := range f.NamedValues[name] {
+ 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})
}
- delete(f.NamedValues, name)
case t.IsComplex():
rName, iName := f.fe.SplitComplex(name)
newNames = append(newNames, rName, iName)
- for _, v := range f.NamedValues[name] {
+ 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})
}
- delete(f.NamedValues, name)
case t.IsString():
ptrName, lenName := f.fe.SplitString(name)
newNames = append(newNames, ptrName, lenName)
- for _, v := range f.NamedValues[name] {
+ 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})
}
- delete(f.NamedValues, name)
case t.IsSlice():
ptrName, lenName, capName := f.fe.SplitSlice(name)
newNames = append(newNames, ptrName, lenName, capName)
- for _, v := range f.NamedValues[name] {
+ 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})
}
- delete(f.NamedValues, name)
case t.IsInterface():
typeName, dataName := f.fe.SplitInterface(name)
newNames = append(newNames, typeName, dataName)
- for _, v := range f.NamedValues[name] {
+ 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})
}
- delete(f.NamedValues, name)
case t.IsFloat():
// floats are never decomposed, even ones bigger than RegSize
- newNames = append(newNames, name)
case t.Size() > f.Config.RegSize:
f.Fatalf("undecomposed named type %s %v", name, t)
- default:
- newNames = append(newNames, name)
}
}
- f.Names = newNames
+
+ deleteNamedVals(f, toDelete)
+ f.Names = append(f.Names, newNames...)
}
func decomposeBuiltInPhi(v *Value) {
@@ -263,14 +266,20 @@ func decomposeUserArrayInto(f *Func, name LocalSlot, slots []LocalSlot) []LocalS
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])
}
- // delete the name for the array as a whole
- delete(f.NamedValues, name)
+ 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)
@@ -300,17 +309,23 @@ func decomposeUserStructInto(f *Func, name LocalSlot, slots []LocalSlot) []Local
}
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])
}
}
- // remove the name of the struct as a whole
- delete(f.NamedValues, name)
+ 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
@@ -400,3 +415,35 @@ func StructMakeOp(nf int) Op {
}
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]
+ }
+ }
+}
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