qbit/go
1
0
Fork 0
mirror of https://github.com/golang/go synced 2024-11-17 18:04:48 -07:00
Code Releases Activity

[dev.regabi] cmd/compile: move stack objects to liveness

Browse Source 
Calculating and emitting stack objects are essentially part of
liveness analysis, so move the code from ssagen to liveness. Allows
unexporting liveness.ShouldTrack.

Passes toolstash -cmp.

Change-Id: I88b5b2e75b8dfb46b8b03a2fa09a9236865cbf3e
Reviewed-on: https://go-review.googlesource.com/c/go/+/284413
Trust: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>
This commit is contained in:
Matthew Dempsky 2021-01-17 22:05:50 -08:00
parent 6113db0bb4
commit 422f38fb6c
2 changed files with 50 additions and 53 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

53
src/cmd/compile/internal/liveness/plive.go
View File

@ -17,12 +17,14 @@ package liveness
import (
"crypto/md5"
"fmt"
"sort"
"strings"
"cmd/compile/internal/base"
"cmd/compile/internal/bitvec"
"cmd/compile/internal/ir"
"cmd/compile/internal/objw"
"cmd/compile/internal/reflectdata"
"cmd/compile/internal/ssa"
"cmd/compile/internal/typebits"
"cmd/compile/internal/types"
@ -174,13 +176,13 @@ type progeffectscache struct {
initialized bool
}
// ShouldTrack reports whether the liveness analysis
// shouldTrack reports whether the liveness analysis
// should track the variable n.
// We don't care about variables that have no pointers,
// nor do we care about non-local variables,
// nor do we care about empty structs (handled by the pointer check),
// nor do we care about the fake PAUTOHEAP variables.
func ShouldTrack(n *ir.Name) bool {
func shouldTrack(n *ir.Name) bool {
return (n.Class == ir.PAUTO && n.Esc() != ir.EscHeap || n.Class == ir.PPARAM || n.Class == ir.PPARAMOUT) && n.Type().HasPointers()
}
@ -189,7 +191,7 @@ func ShouldTrack(n *ir.Name) bool {
func getvariables(fn *ir.Func) ([]*ir.Name, map[*ir.Name]int32) {
var vars []*ir.Name
for _, n := range fn.Dcl {
if ShouldTrack(n) {
if shouldTrack(n) {
vars = append(vars, n)
}
}
@ -1179,9 +1181,54 @@ func Compute(curfn *ir.Func, f *ssa.Func, stkptrsize int64, pp *objw.Progs) Map
p.To.Name = obj.NAME_EXTERN
p.To.Sym = fninfo.GCLocals
if x := lv.emitStackObjects(); x != nil {
p := pp.Prog(obj.AFUNCDATA)
p.From.SetConst(objabi.FUNCDATA_StackObjects)
p.To.Type = obj.TYPE_MEM
p.To.Name = obj.NAME_EXTERN
p.To.Sym = x
}
return lv.livenessMap
}
func (lv *liveness) emitStackObjects() *obj.LSym {
var vars []*ir.Name
for _, n := range lv.fn.Dcl {
if shouldTrack(n) && n.Addrtaken() && n.Esc() != ir.EscHeap {
vars = append(vars, n)
}
}
if len(vars) == 0 {
return nil
}
// Sort variables from lowest to highest address.
sort.Slice(vars, func(i, j int) bool { return vars[i].FrameOffset() < vars[j].FrameOffset() })
// Populate the stack object data.
// Format must match runtime/stack.go:stackObjectRecord.
x := base.Ctxt.Lookup(lv.fn.LSym.Name + ".stkobj")
lv.fn.LSym.Func().StackObjects = x
off := 0
off = objw.Uintptr(x, off, uint64(len(vars)))
for _, v := range vars {
// Note: arguments and return values have non-negative Xoffset,
// in which case the offset is relative to argp.
// Locals have a negative Xoffset, in which case the offset is relative to varp.
off = objw.Uintptr(x, off, uint64(v.FrameOffset()))
off = objw.SymPtr(x, off, reflectdata.TypeLinksym(v.Type()), 0)
}
if base.Flag.Live != 0 {
for _, v := range vars {
base.WarnfAt(v.Pos(), "stack object %v %v", v, v.Type())
}
}
return x
}
// isfat reports whether a variable of type t needs multiple assignments to initialize.
// For example:
//

50
src/cmd/compile/internal/ssagen/ssa.go
View File

@ -6467,55 +6467,6 @@ func (s *State) DebugFriendlySetPosFrom(v *ssa.Value) {
}
}
// byXoffset implements sort.Interface for []*ir.Name using Xoffset as the ordering.
type byXoffset []*ir.Name
func (s byXoffset) Len() int { return len(s) }
func (s byXoffset) Less(i, j int) bool { return s[i].FrameOffset() < s[j].FrameOffset() }
func (s byXoffset) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
func emitStackObjects(e *ssafn, pp *objw.Progs) {
var vars []*ir.Name
for _, n := range e.curfn.Dcl {
if liveness.ShouldTrack(n) && n.Addrtaken() && n.Esc() != ir.EscHeap {
vars = append(vars, n)
}
}
if len(vars) == 0 {
return
}
// Sort variables from lowest to highest address.
sort.Sort(byXoffset(vars))
// Populate the stack object data.
// Format must match runtime/stack.go:stackObjectRecord.
x := base.Ctxt.Lookup(e.curfn.LSym.Name + ".stkobj")
e.curfn.LSym.Func().StackObjects = x
off := 0
off = objw.Uintptr(x, off, uint64(len(vars)))
for _, v := range vars {
// Note: arguments and return values have non-negative Xoffset,
// in which case the offset is relative to argp.
// Locals have a negative Xoffset, in which case the offset is relative to varp.
off = objw.Uintptr(x, off, uint64(v.FrameOffset()))
off = objw.SymPtr(x, off, reflectdata.TypeLinksym(v.Type()), 0)
}
// Emit a funcdata pointing at the stack object data.
p := pp.Prog(obj.AFUNCDATA)
p.From.SetConst(objabi.FUNCDATA_StackObjects)
p.To.Type = obj.TYPE_MEM
p.To.Name = obj.NAME_EXTERN
p.To.Sym = x
if base.Flag.Live != 0 {
for _, v := range vars {
base.WarnfAt(v.Pos(), "stack object %v %s", v, v.Type().String())
}
}
}
// genssa appends entries to pp for each instruction in f.
func genssa(f *ssa.Func, pp *objw.Progs) {
var s State
@ -6523,7 +6474,6 @@ func genssa(f *ssa.Func, pp *objw.Progs) {
e := f.Frontend().(*ssafn)
s.livenessMap = liveness.Compute(e.curfn, f, e.stkptrsize, pp)
emitStackObjects(e, pp)
openDeferInfo := e.curfn.LSym.Func().OpenCodedDeferInfo
if openDeferInfo != nil {