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Revert "cmd/compile/internal: merge stack slots for selected local auto vars"

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This reverts CL 553055.

Reason for revert: causes crypto/ecdsa failures on linux ppc64/s390x builders

Change-Id: I9266b030693a5b6b1e667a009de89d613755b048
Reviewed-on: https://go-review.googlesource.com/c/go/+/575236
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
Auto-Submit: Than McIntosh <thanm@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
This commit is contained in:
Cuong Manh Le 2024-03-29 23:44:59 +00:00 committed by Gopher Robot
parent 89f7805c2e
commit 0bf6071066
14 changed files with 222 additions and 1512 deletions
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4
src/cmd/compile/internal/base/debug.go
View File

@ -41,10 +41,6 @@ type DebugFlags struct {
LoopVarHash string `help:"for debugging changes in loop behavior. Overrides experiment and loopvar flag."` LoopVarHash string `help:"for debugging changes in loop behavior. Overrides experiment and loopvar flag."`
LocationLists int `help:"print information about DWARF location list creation"` LocationLists int `help:"print information about DWARF location list creation"`
MaxShapeLen int `help:"hash shape names longer than this threshold (default 500)" concurrent:"ok"` MaxShapeLen int `help:"hash shape names longer than this threshold (default 500)" concurrent:"ok"`
MergeLocals int `help:"merge together non-interfering local stack slots" concurrent:"ok"`
MergeLocalsDumpFunc string `help:"dump specified func in merge locals"`
MergeLocalsHash string `help:"hash value for debugging stack slot merging of local variables" concurrent:"ok"`
MergeLocalsTrace int `help:"trace debug output for locals merging"`
Nil int `help:"print information about nil checks"` Nil int `help:"print information about nil checks"`
NoOpenDefer int `help:"disable open-coded defers" concurrent:"ok"` NoOpenDefer int `help:"disable open-coded defers" concurrent:"ok"`
NoRefName int `help:"do not include referenced symbol names in object file" concurrent:"ok"` NoRefName int `help:"do not include referenced symbol names in object file" concurrent:"ok"`

4
src/cmd/compile/internal/base/flag.go
View File

@ -184,7 +184,6 @@ func ParseFlags() {
Debug.SyncFrames = -1 // disable sync markers by default Debug.SyncFrames = -1 // disable sync markers by default
Debug.ZeroCopy = 1 Debug.ZeroCopy = 1
Debug.RangeFuncCheck = 1 Debug.RangeFuncCheck = 1
Debug.MergeLocals = 1
Debug.Checkptr = -1 // so we can tell whether it is set explicitly Debug.Checkptr = -1 // so we can tell whether it is set explicitly
@ -261,9 +260,6 @@ func ParseFlags() {
if Debug.PGOHash != "" { if Debug.PGOHash != "" {
PGOHash = NewHashDebug("pgohash", Debug.PGOHash, nil) PGOHash = NewHashDebug("pgohash", Debug.PGOHash, nil)
} }
if Debug.MergeLocalsHash != "" {
MergeLocalsHash = NewHashDebug("mergelocals", Debug.MergeLocalsHash, nil)
}
if Flag.MSan && !platform.MSanSupported(buildcfg.GOOS, buildcfg.GOARCH) { if Flag.MSan && !platform.MSanSupported(buildcfg.GOOS, buildcfg.GOARCH) {
log.Fatalf("%s/%s does not support -msan", buildcfg.GOOS, buildcfg.GOARCH) log.Fatalf("%s/%s does not support -msan", buildcfg.GOOS, buildcfg.GOARCH)

1
src/cmd/compile/internal/base/hashdebug.go
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@ -56,7 +56,6 @@ var hashDebug *HashDebug
var FmaHash *HashDebug // for debugging fused-multiply-add floating point changes var FmaHash *HashDebug // for debugging fused-multiply-add floating point changes
var LoopVarHash *HashDebug // for debugging shared/private loop variable changes var LoopVarHash *HashDebug // for debugging shared/private loop variable changes
var PGOHash *HashDebug // for debugging PGO optimization decisions var PGOHash *HashDebug // for debugging PGO optimization decisions
var MergeLocalsHash *HashDebug // for debugging local stack slot merging changes
// DebugHashMatchPkgFunc reports whether debug variable Gossahash // DebugHashMatchPkgFunc reports whether debug variable Gossahash
// //

3
src/cmd/compile/internal/ir/name.go
View File

@ -194,7 +194,6 @@ const (
nameLibfuzzer8BitCounter // if PEXTERN should be assigned to __sancov_cntrs section nameLibfuzzer8BitCounter // if PEXTERN should be assigned to __sancov_cntrs section
nameCoverageAuxVar // instrumentation counter var or pkg ID for cmd/cover nameCoverageAuxVar // instrumentation counter var or pkg ID for cmd/cover
nameAlias // is type name an alias nameAlias // is type name an alias
nameNonMergeable // not a candidate for stack slot merging
) )
func (n *Name) Readonly() bool { return n.flags&nameReadonly != 0 } func (n *Name) Readonly() bool { return n.flags&nameReadonly != 0 }
@ -210,7 +209,6 @@ func (n *Name) InlLocal() bool { return n.flags&nameInlLocal !=
func (n *Name) OpenDeferSlot() bool { return n.flags&nameOpenDeferSlot != 0 } func (n *Name) OpenDeferSlot() bool { return n.flags&nameOpenDeferSlot != 0 }
func (n *Name) Libfuzzer8BitCounter() bool { return n.flags&nameLibfuzzer8BitCounter != 0 } func (n *Name) Libfuzzer8BitCounter() bool { return n.flags&nameLibfuzzer8BitCounter != 0 }
func (n *Name) CoverageAuxVar() bool { return n.flags&nameCoverageAuxVar != 0 } func (n *Name) CoverageAuxVar() bool { return n.flags&nameCoverageAuxVar != 0 }
func (n *Name) NonMergeable() bool { return n.flags&nameNonMergeable != 0 }
func (n *Name) setReadonly(b bool) { n.flags.set(nameReadonly, b) } func (n *Name) setReadonly(b bool) { n.flags.set(nameReadonly, b) }
func (n *Name) SetNeedzero(b bool) { n.flags.set(nameNeedzero, b) } func (n *Name) SetNeedzero(b bool) { n.flags.set(nameNeedzero, b) }
@ -225,7 +223,6 @@ func (n *Name) SetInlLocal(b bool) { n.flags.set(nameInlLocal, b
func (n *Name) SetOpenDeferSlot(b bool) { n.flags.set(nameOpenDeferSlot, b) } func (n *Name) SetOpenDeferSlot(b bool) { n.flags.set(nameOpenDeferSlot, b) }
func (n *Name) SetLibfuzzer8BitCounter(b bool) { n.flags.set(nameLibfuzzer8BitCounter, b) } func (n *Name) SetLibfuzzer8BitCounter(b bool) { n.flags.set(nameLibfuzzer8BitCounter, b) }
func (n *Name) SetCoverageAuxVar(b bool) { n.flags.set(nameCoverageAuxVar, b) } func (n *Name) SetCoverageAuxVar(b bool) { n.flags.set(nameCoverageAuxVar, b) }
func (n *Name) SetNonMergeable(b bool) { n.flags.set(nameNonMergeable, b) }
// OnStack reports whether variable n may reside on the stack. // OnStack reports whether variable n may reside on the stack.
func (n *Name) OnStack() bool { func (n *Name) OnStack() bool {

691
src/cmd/compile/internal/liveness/mergelocals.go
View File

@ -1,691 +0,0 @@
// Copyright 2024 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 liveness
import (
"cmd/compile/internal/base"
"cmd/compile/internal/bitvec"
"cmd/compile/internal/ir"
"cmd/compile/internal/reflectdata"
"cmd/compile/internal/ssa"
"cmd/internal/obj"
"cmd/internal/src"
"fmt"
"os"
"path/filepath"
"sort"
"strings"
)
// MergeLocalsState encapsulates information about which AUTO
// (stack-allocated) variables within a function can be safely
// merged/overlapped, e.g. share a stack slot with some other auto).
// An instance of MergeLocalsState is produced by MergeLocals() below
// and then consumed in ssagen.AllocFrame. The map 'partition' contains
// entries of the form <N,SL> where N is an *ir.Name and SL is a slice
// holding the indices (within 'vars') of other variables that share the
// same slot. For example, if a function contains five variables where
// v1/v2/v3 are safe to overlap and v4/v5 are safe to overlap, the
// MergeLocalsState content might look like
//
// vars: [v1, v2, v3, v4, v5]
// partition: v1 -> [1, 0, 2], v2 -> [1, 0, 2], v3 -> [1, 0, 2]
// v4 -> [3, 4], v5 -> [3, 4]
//
// A nil MergeLocalsState indicates that no local variables meet the
// necessary criteria for overlap.
type MergeLocalsState struct {
// contains auto vars that participate in overlapping
vars []*ir.Name
// maps auto variable to overlap partition
partition map[*ir.Name][]int
}
// candRegion is a sub-range (start, end) corresponding to an interval
// [st,en] within the list of candidate variables.
type candRegion struct {
st, en int
}
// MergeLocals analyzes the specified ssa function f to determine which
// of its auto variables can safely share the same stack slot, returning
// a state object that describes how the overlap should be done.
func MergeLocals(fn *ir.Func, f *ssa.Func) *MergeLocalsState {
cands, idx, regions := collectMergeCandidates(fn)
if len(regions) == 0 {
return nil
}
lv := newliveness(fn, f, cands, idx, 0)
// If we have a local variable such as "r2" below that's written
// but then not read, something like:
//
// vardef r1
// r1.x = ...
// vardef r2
// r2.x = 0
// r2.y = ...
// <call foo>
// // no subsequent use of r2
// ... = r1.x
//
// then for the purpose of calculating stack maps at the call, we
// can ignore "r2" completely during liveness analysis for stack
// maps, however for stack slock merging we most definitely want
// to treat the writes as "uses".
lv.conservativeWrites = true
lv.prologue()
lv.solve()
cs := &cstate{
fn: fn,
ibuilders: make([]IntervalsBuilder, len(cands)),
}
computeIntervals(lv, cs)
rv := performMerging(lv, cs, regions)
if err := rv.check(); err != nil {
base.FatalfAt(fn.Pos(), "invalid mergelocals state: %v", err)
}
return rv
}
// Subsumed returns whether variable n is subsumed, e.g. appears
// in an overlap position but is not the leader in that partition.
func (mls *MergeLocalsState) Subsumed(n *ir.Name) bool {
if sl, ok := mls.partition[n]; ok && mls.vars[sl[0]] != n {
return true
}
return false
}
// IsLeader returns whether a variable n is the leader (first element)
// in a sharing partition.
func (mls *MergeLocalsState) IsLeader(n *ir.Name) bool {
if sl, ok := mls.partition[n]; ok && mls.vars[sl[0]] == n {
return true
}
return false
}
// Leader returns the leader variable for subsumed var n.
func (mls *MergeLocalsState) Leader(n *ir.Name) *ir.Name {
if sl, ok := mls.partition[n]; ok {
if mls.vars[sl[0]] == n {
panic("variable is not subsumed")
}
return mls.vars[sl[0]]
}
panic("not a merge candidate")
}
// Followers writes a list of the followers for leader n into the slice tmp.
func (mls *MergeLocalsState) Followers(n *ir.Name, tmp []*ir.Name) []*ir.Name {
tmp = tmp[:0]
sl, ok := mls.partition[n]
if !ok {
panic("no entry for leader")
}
if mls.vars[sl[0]] != n {
panic("followers invoked on subsumed var")
}
for _, k := range sl[1:] {
tmp = append(tmp, mls.vars[k])
}
sort.SliceStable(tmp, func(i, j int) bool {
return tmp[i].Sym().Name < tmp[j].Sym().Name
})
return tmp
}
// EstSavings returns the estimated reduction in stack size for
// the given merge locals state.
func (mls *MergeLocalsState) EstSavings() int {
tot := 0
for n := range mls.partition {
if mls.Subsumed(n) {
tot += int(n.Type().Size())
}
}
return tot
}
// check tests for various inconsistencies and problems in mls,
// returning an error if any problems are found.
func (mls *MergeLocalsState) check() error {
if mls == nil {
return nil
}
used := make(map[int]bool)
seenv := make(map[*ir.Name]int)
for ii, v := range mls.vars {
if prev, ok := seenv[v]; ok {
return fmt.Errorf("duplicate var %q in vslots: %d and %d\n",
v.Sym().Name, ii, prev)
}
seenv[v] = ii
}
for k, sl := range mls.partition {
// length of slice value needs to be more than 1
if len(sl) < 2 {
return fmt.Errorf("k=%q v=%+v slice len %d invalid",
k.Sym().Name, sl, len(sl))
}
// values in the slice need to be var indices
for i, v := range sl {
if v < 0 || v > len(mls.vars)-1 {
return fmt.Errorf("k=%q v=+%v slpos %d vslot %d out of range of m.v", k.Sym().Name, sl, i, v)
}
}
}
for k, sl := range mls.partition {
foundk := false
for i, v := range sl {
vv := mls.vars[v]
if i == 0 {
if !mls.IsLeader(vv) {
return fmt.Errorf("k=%s v=+%v slpos 0 vslot %d IsLeader(%q) is false should be true", k.Sym().Name, sl, v, vv.Sym().Name)
}
} else {
if !mls.Subsumed(vv) {
return fmt.Errorf("k=%s v=+%v slpos %d vslot %d Subsumed(%q) is false should be true", k.Sym().Name, sl, i, v, vv.Sym().Name)
}
if mls.Leader(vv) != mls.vars[sl[0]] {
return fmt.Errorf("k=%s v=+%v slpos %d vslot %d Leader(%q) got %v want %v", k.Sym().Name, sl, i, v, vv.Sym().Name, mls.Leader(vv), mls.vars[sl[0]])
}
}
if vv == k {
foundk = true
if used[v] {
return fmt.Errorf("k=%s v=+%v val slice used violation at slpos %d vslot %d", k.Sym().Name, sl, i, v)
}
used[v] = true
}
}
if !foundk {
return fmt.Errorf("k=%s v=+%v slice value missing k", k.Sym().Name, sl)
}
}
for i := range used {
if !used[i] {
return fmt.Errorf("pos %d var %q unused", i, mls.vars[i])
}
}
return nil
}
func (mls *MergeLocalsState) String() string {
var leaders []*ir.Name
for n, sl := range mls.partition {
if n == mls.vars[sl[0]] {
leaders = append(leaders, n)
}
}
sort.Slice(leaders, func(i, j int) bool {
return leaders[i].Sym().Name < leaders[j].Sym().Name
})
var sb strings.Builder
for _, n := range leaders {
sb.WriteString(n.Sym().Name + ":")
sl := mls.partition[n]
for _, k := range sl[1:] {
n := mls.vars[k]
sb.WriteString(" " + n.Sym().Name)
}
sb.WriteString("\n")
}
return sb.String()
}
// collectMergeCandidates visits all of the AUTO vars declared in
// function fn and returns a list of candidate variables for merging /
// overlapping. Return values are: 1) a slice of ir.Name's
// corresponding to the candidates, 2) a map that maps ir.Name to slot
// in the slice, and 3) a slice containing regions (start/end pairs)
// corresponding to variables that could be overlapped provided that
// their lifetimes are disjoint.
func collectMergeCandidates(fn *ir.Func) ([]*ir.Name, map[*ir.Name]int32, []candRegion) {
m := make(map[*ir.Name]int32)
var cands []*ir.Name
var regions []candRegion
// Collect up the available set of appropriate AUTOs in the
// function as a first step.
for _, n := range fn.Dcl {
if !n.Used() {
continue
}
if !ssa.IsMergeCandidate(n) {
continue
}
cands = append(cands, n)
}
if len(cands) < 2 {
return nil, nil, nil
}
// Sort by pointerness, size, and then name.
sort.SliceStable(cands, func(i, j int) bool {
ci, cj := cands[i], cands[j]
ihp, jhp := 0, 0
var ilsym, jlsym *obj.LSym
if ci.Type().HasPointers() {
ihp = 1
ilsym, _, _ = reflectdata.GCSym(ci.Type())
}
if cj.Type().HasPointers() {
jhp = 1
jlsym, _, _ = reflectdata.GCSym(cj.Type())
}
if ihp != jhp {
return ihp < jhp
}
if ci.Type().Size() != cj.Type().Size() {
return ci.Type().Size() < cj.Type().Size()
}
if ihp != 0 && jhp != 0 && ilsym != jlsym {
// FIXME: find less clunky way to do this
return fmt.Sprintf("%v", ilsym) < fmt.Sprintf("%v", jlsym)
}
if ci.Sym().Name != cj.Sym().Name {
return ci.Sym().Name < cj.Sym().Name
}
return fmt.Sprintf("%v", ci.Pos()) < fmt.Sprintf("%v", ci.Pos())
})
if base.Debug.MergeLocalsTrace > 1 {
fmt.Fprintf(os.Stderr, "=-= raw cand list for func %v:\n", fn)
for i := range cands {
dumpCand(cands[i], i)
}
}
// Now generate a pruned candidate list-- we only want to return a
// non-empty list if there is some possibility of overlapping two
// vars.
var pruned []*ir.Name
st := 0
for {
en := nextRegion(cands, st)
if en == -1 {
break
}
if st == en {
// region has just one element, we can skip it
st++
continue
}
pst := len(pruned)
pen := pst + (en - st)
if base.Debug.MergeLocalsTrace > 1 {
fmt.Fprintf(os.Stderr, "=-= add part %d -> %d\n", pst, pen)
}
// non-empty region, add to pruned
pruned = append(pruned, cands[st:en+1]...)
regions = append(regions, candRegion{st: pst, en: pen})
st = en + 1
}
if len(pruned) < 2 {
return nil, nil, nil
}
for i, n := range pruned {
m[n] = int32(i)
}
if base.Debug.MergeLocalsTrace > 1 {
fmt.Fprintf(os.Stderr, "=-= pruned candidate list for func %v:\n", fn)
for i := range pruned {
dumpCand(pruned[i], i)
}
}
return pruned, m, regions
}
// nextRegion starts at location idx and walks forward in the cands
// slice looking for variables that are "compatible" (overlappable)
// with the variable at position idx; it returns the end of the new
// region (range of compatible variables starting at idx).
func nextRegion(cands []*ir.Name, idx int) int {
n := len(cands)
if idx >= n {
return -1
}
c0 := cands[idx]
hp0 := c0.Type().HasPointers()
for j := idx + 1; j < n; j++ {
cj := cands[j]
hpj := cj.Type().HasPointers()
ok := true
if hp0 {
if !hpj || c0.Type().Size() != cj.Type().Size() {
return j - 1
}
// GC shape must match if both types have pointers.
gcsym0, _, _ := reflectdata.GCSym(c0.Type())
gcsymj, _, _ := reflectdata.GCSym(cj.Type())
if gcsym0 != gcsymj {
return j - 1
}
} else {
// If no pointers, match size only.
if !ok || hp0 != hpj || c0.Type().Size() != cj.Type().Size() {
return j - 1
}
}
}
return n - 1
}
type cstate struct {
fn *ir.Func
ibuilders []IntervalsBuilder
}
// mergeVisitRegion tries to perform overlapping of variables with a
// given subrange of cands described by st and en (indices into our
// candidate var list), where the variables within this range have
// already been determined to be compatible with respect to type,
// size, etc. Overlapping is done in a a greedy fashion: we select the
// first element in the st->en range, then walk the rest of the
// elements adding in vars whose lifetimes don't overlap with the
// first element, then repeat the process until we run out of work to do.
func (mls *MergeLocalsState) mergeVisitRegion(lv *liveness, ivs []Intervals, st, en int) {
if base.Debug.MergeLocalsTrace > 1 {
fmt.Fprintf(os.Stderr, "=-= mergeVisitRegion(st=%d, en=%d)\n", st, en)
}
n := en - st + 1
used := bitvec.New(int32(n))
nxt := func(slot int) int {
for c := slot - st; c < n; c++ {
if used.Get(int32(c)) {
continue
}
return c + st
}
return -1
}
navail := n
cands := lv.vars
if base.Debug.MergeLocalsTrace > 1 {
fmt.Fprintf(os.Stderr, " =-= navail = %d\n", navail)
}
for navail >= 2 {
leader := nxt(st)
used.Set(int32(leader - st))
navail--
if base.Debug.MergeLocalsTrace > 1 {
fmt.Fprintf(os.Stderr, " =-= begin leader %d used=%s\n", leader,
used.String())
}
elems := []int{leader}
lints := ivs[leader]
for succ := nxt(leader + 1); succ != -1; succ = nxt(succ + 1) {
// Skip if de-selected by merge locals hash.
if base.Debug.MergeLocalsHash != "" {
if !base.MergeLocalsHash.MatchPosWithInfo(cands[succ].Pos(), "mergelocals", nil) {
continue
}
}
// Skip if already used.
if used.Get(int32(succ - st)) {
continue
}
if base.Debug.MergeLocalsTrace > 1 {
fmt.Fprintf(os.Stderr, " =-= overlap of %d[%v] {%s} with %d[%v] {%s} is: %v\n", leader, cands[leader], lints.String(), succ, cands[succ], ivs[succ].String(), lints.Overlaps(ivs[succ]))
}
// Can we overlap leader with this var?
if lints.Overlaps(ivs[succ]) {
continue
} else {
// Add to overlap set.
elems = append(elems, succ)
lints = lints.Merge(ivs[succ])
}
}
if len(elems) > 1 {
// We found some things to overlap with leader. Add the
// candidate elements to "vars" and update "partition".
off := len(mls.vars)
sl := make([]int, len(elems))
for i, candslot := range elems {
sl[i] = off + i
mls.vars = append(mls.vars, cands[candslot])
mls.partition[cands[candslot]] = sl
}
navail -= (len(elems) - 1)
for i := range elems {
used.Set(int32(elems[i] - st))
}
if base.Debug.MergeLocalsTrace > 1 {
fmt.Fprintf(os.Stderr, "=-= overlapping %+v:\n", sl)
for i := range sl {
dumpCand(mls.vars[sl[i]], sl[i])
}
for i, v := range elems {
fmt.Fprintf(os.Stderr, "=-= %d: sl=%d %s\n", i, v, ivs[v])
}
}
}
}
}
// performMerging carries out variable merging within each of the
// candidate ranges in regions, returning a state object
// that describes the variable overlaps.
func performMerging(lv *liveness, cs *cstate, regions []candRegion) *MergeLocalsState {
cands := lv.vars
mls := &MergeLocalsState{
partition: make(map[*ir.Name][]int),
}
// Finish intervals construction.
ivs := make([]Intervals, len(cands))
for i := range cands {
var err error
ivs[i], err = cs.ibuilders[i].Finish()
if err != nil {
ninstr := 0
if base.Debug.MergeLocalsTrace != 0 {
iidx := 0
for k := 0; k < len(lv.f.Blocks); k++ {
b := lv.f.Blocks[k]
fmt.Fprintf(os.Stderr, "\n")
for _, v := range b.Values {
fmt.Fprintf(os.Stderr, " b%d %d: %s\n", k, iidx, v.LongString())
iidx++
ninstr++
}
}
}
base.FatalfAt(cands[i].Pos(), "interval construct error for var %q in func %q (%d instrs): %v", cands[i].Sym().Name, ir.FuncName(cs.fn), ninstr, err)
return nil
}
}
// Dump state before attempting overlap.
if base.Debug.MergeLocalsTrace > 1 {
fmt.Fprintf(os.Stderr, "=-= cands live before overlap:\n")
for i := range cands {
c := cands[i]
fmt.Fprintf(os.Stderr, "%d: %v sz=%d ivs=%s\n",
i, c.Sym().Name, c.Type().Size(), ivs[i].String())
}
fmt.Fprintf(os.Stderr, "=-= regions (%d): ", len(regions))
for _, cr := range regions {
fmt.Fprintf(os.Stderr, " [%d,%d]", cr.st, cr.en)
}
fmt.Fprintf(os.Stderr, "\n")
}
if base.Debug.MergeLocalsTrace > 1 {
fmt.Fprintf(os.Stderr, "=-= len(regions) = %d\n", len(regions))
}
// Apply a greedy merge/overlap strategy within each region
// of compatible variables.
for _, cr := range regions {
mls.mergeVisitRegion(lv, ivs, cr.st, cr.en)
}
if len(mls.vars) == 0 {
return nil
}
return mls
}
// computeIntervals performs a backwards sweep over the instructions
// of the function we're compiling, building up an Intervals object
// for each candidate variable by looking for upwards exposed uses
// and kills.
func computeIntervals(lv *liveness, cs *cstate) {
nvars := int32(len(lv.vars))
liveout := bitvec.New(nvars)
if base.Debug.MergeLocalsDumpFunc != "" &&
strings.HasSuffix(fmt.Sprintf("%v", cs.fn), base.Debug.MergeLocalsDumpFunc) {
fmt.Fprintf(os.Stderr, "=-= mergelocalsdumpfunc %v:\n", cs.fn)
ii := 0
for k, b := range lv.f.Blocks {
fmt.Fprintf(os.Stderr, "b%d:\n", k)
for _, v := range b.Values {
pos := base.Ctxt.PosTable.Pos(v.Pos)
fmt.Fprintf(os.Stderr, "=-= %d L%d|C%d %s\n", ii, pos.RelLine(), pos.RelCol(), v.LongString())
ii++
}
}
}
// Count instructions.
ninstr := 0
for _, b := range lv.f.Blocks {
ninstr += len(b.Values)
}
// current instruction index during backwards walk
iidx := ninstr - 1
// Make a backwards pass over all blocks
for k := len(lv.f.Blocks) - 1; k >= 0; k-- {
b := lv.f.Blocks[k]
be := lv.blockEffects(b)
if base.Debug.MergeLocalsTrace > 2 {
fmt.Fprintf(os.Stderr, "=-= liveout from tail of b%d: ", k)
for j := range lv.vars {
if be.liveout.Get(int32(j)) {
fmt.Fprintf(os.Stderr, " %q", lv.vars[j].Sym().Name)
}
}
fmt.Fprintf(os.Stderr, "\n")
}
// Take into account effects taking place at end of this basic
// block by comparing our current live set with liveout for
// the block. If a given var was not live before and is now
// becoming live we need to mark this transition with a
// builder "Live" call; similarly if a var was live before and
// is now no longer live, we need a "Kill" call.
for j := range lv.vars {
isLive := liveout.Get(int32(j))
blockLiveOut := be.liveout.Get(int32(j))
if isLive {
if !blockLiveOut {
if base.Debug.MergeLocalsTrace > 2 {
fmt.Fprintf(os.Stderr, "=+= at instr %d block boundary kill of %v\n", iidx, lv.vars[j])
}
cs.ibuilders[j].Kill(iidx)
}
} else if blockLiveOut {
if base.Debug.MergeLocalsTrace > 2 {
fmt.Fprintf(os.Stderr, "=+= at block-end instr %d %v becomes live\n",
iidx, lv.vars[j])
}
cs.ibuilders[j].Live(iidx)
}
}
// Set our working "currently live" set to the previously
// computed live out set for the block.
liveout.Copy(be.liveout)
// Now walk backwards through this block.
for i := len(b.Values) - 1; i >= 0; i-- {
v := b.Values[i]
if base.Debug.MergeLocalsTrace > 2 {
fmt.Fprintf(os.Stderr, "=-= b%d instr %d: %s\n", k, iidx, v.LongString())
}
// Update liveness based on what we see happening in this
// instruction.
pos, e := lv.valueEffects(v)
becomeslive := e&uevar != 0
iskilled := e&varkill != 0
if becomeslive && iskilled {
// we do not ever expect to see both a kill and an
// upwards exposed use given our size constraints.
panic("should never happen")
}
if iskilled && liveout.Get(pos) {
cs.ibuilders[pos].Kill(iidx)
liveout.Unset(pos)
if base.Debug.MergeLocalsTrace > 2 {
fmt.Fprintf(os.Stderr, "=+= at instr %d kill of %v\n",
iidx, lv.vars[pos])
}
} else if becomeslive && !liveout.Get(pos) {
cs.ibuilders[pos].Live(iidx)
liveout.Set(pos)
if base.Debug.MergeLocalsTrace > 2 {
fmt.Fprintf(os.Stderr, "=+= at instr %d upwards-exposed use of %v\n",
iidx, lv.vars[pos])
}
}
iidx--
}
if b == lv.f.Entry {
for j, v := range lv.vars {
if liveout.Get(int32(j)) {
lv.f.Fatalf("%v %L recorded as live on entry",
lv.fn.Nname, v)
}
}
}
}
if iidx != -1 {
panic("iidx underflow")
}
}
func dumpCand(c *ir.Name, i int) {
fmtFullPos := func(p src.XPos) string {
var sb strings.Builder
sep := ""
base.Ctxt.AllPos(p, func(pos src.Pos) {
fmt.Fprintf(&sb, sep)
sep = "|"
file := filepath.Base(pos.Filename())
fmt.Fprintf(&sb, "%s:%d:%d", file, pos.Line(), pos.Col())
})
return sb.String()
}
fmt.Fprintf(os.Stderr, " %d: %s %q sz=%d hp=%v t=%v\n",
i, fmtFullPos(c.Pos()), c.Sym().Name, c.Type().Size(),
c.Type().HasPointers(), c.Type())
}
// for unit testing only.
func MakeMergeLocalsState(partition map[*ir.Name][]int, vars []*ir.Name) (*MergeLocalsState, error) {
mls := &MergeLocalsState{partition: partition, vars: vars}
if err := mls.check(); err != nil {
return nil, err
}
return mls, nil
}

22
src/cmd/compile/internal/liveness/plive.go
View File

@ -143,11 +143,6 @@ type liveness struct {
doClobber bool // Whether to clobber dead stack slots in this function. doClobber bool // Whether to clobber dead stack slots in this function.
noClobberArgs bool // Do not clobber function arguments noClobberArgs bool // Do not clobber function arguments
// treat "dead" writes as equivalent to reads during the analysis;
// used only during liveness analysis for stack slot merging (doesn't
// make sense for stackmap analysis).
conservativeWrites bool
} }
// Map maps from *ssa.Value to StackMapIndex. // Map maps from *ssa.Value to StackMapIndex.
@ -317,12 +312,8 @@ func (lv *liveness) valueEffects(v *ssa.Value) (int32, liveEffect) {
if e&(ssa.SymRead|ssa.SymAddr) != 0 { if e&(ssa.SymRead|ssa.SymAddr) != 0 {
effect |= uevar effect |= uevar
} }
if e&ssa.SymWrite != 0 { if e&ssa.SymWrite != 0 && (!isfat(n.Type()) || v.Op == ssa.OpVarDef) {
if !isfat(n.Type()) || v.Op == ssa.OpVarDef {
effect |= varkill effect |= varkill
} else if lv.conservativeWrites {
effect |= uevar
}
} }
if effect == 0 { if effect == 0 {
@ -459,11 +450,6 @@ func (lv *liveness) blockEffects(b *ssa.Block) *blockEffects {
// this argument and the in arguments are always assumed live. The vars // this argument and the in arguments are always assumed live. The vars
// argument is a slice of *Nodes. // argument is a slice of *Nodes.
func (lv *liveness) pointerMap(liveout bitvec.BitVec, vars []*ir.Name, args, locals bitvec.BitVec) { func (lv *liveness) pointerMap(liveout bitvec.BitVec, vars []*ir.Name, args, locals bitvec.BitVec) {
var slotsSeen map[int64]*ir.Name
checkForDuplicateSlots := base.Debug.MergeLocals != 0
if checkForDuplicateSlots {
slotsSeen = make(map[int64]*ir.Name)
}
for i := int32(0); ; i++ { for i := int32(0); ; i++ {
i = liveout.Next(i) i = liveout.Next(i)
if i < 0 { if i < 0 {
@ -482,12 +468,6 @@ func (lv *liveness) pointerMap(liveout bitvec.BitVec, vars []*ir.Name, args, loc
fallthrough // PPARAMOUT in registers acts memory-allocates like an AUTO fallthrough // PPARAMOUT in registers acts memory-allocates like an AUTO
case ir.PAUTO: case ir.PAUTO:
typebits.Set(node.Type(), node.FrameOffset()+lv.stkptrsize, locals) typebits.Set(node.Type(), node.FrameOffset()+lv.stkptrsize, locals)
if checkForDuplicateSlots {
if prev, ok := slotsSeen[node.FrameOffset()]; ok {
base.FatalfAt(node.Pos(), "two vars live at pointerMap generation: %q and %q", prev.Sym().Name, node.Sym().Name)
}
slotsSeen[node.FrameOffset()] = node
}
} }
} }
} }

5
src/cmd/compile/internal/ssa/check.go
View File

@ -314,9 +314,8 @@ func checkFunc(f *Func) {
f.Fatalf("bad arg 1 type to %s: want integer, have %s", v.Op, v.Args[1].LongString()) f.Fatalf("bad arg 1 type to %s: want integer, have %s", v.Op, v.Args[1].LongString())
} }
case OpVarDef: case OpVarDef:
n := v.Aux.(*ir.Name) if !v.Aux.(*ir.Name).Type().HasPointers() {
if !n.Type().HasPointers() && !IsMergeCandidate(n) { f.Fatalf("vardef must have pointer type %s", v.Aux.(*ir.Name).Type().String())
f.Fatalf("vardef must be merge candidate or have pointer type %s", v.Aux.(*ir.Name).Type().String())
} }
case OpNilCheck: case OpNilCheck:
// nil checks have pointer type before scheduling, and // nil checks have pointer type before scheduling, and

22
src/cmd/compile/internal/ssa/func.go
View File

@ -838,25 +838,5 @@ func (f *Func) useFMA(v *Value) bool {
// NewLocal returns a new anonymous local variable of the given type. // NewLocal returns a new anonymous local variable of the given type.
func (f *Func) NewLocal(pos src.XPos, typ *types.Type) *ir.Name { func (f *Func) NewLocal(pos src.XPos, typ *types.Type) *ir.Name {
nn := typecheck.TempAt(pos, f.fe.Func(), typ) // Note: adds new auto to fn.Dcl list return typecheck.TempAt(pos, f.fe.Func(), typ) // Note: adds new auto to fn.Dcl list
nn.SetNonMergeable(true)
return nn
}
// IsMergeCandidate returns true if variable n could participate in
// stack slot merging. For now we're restricting the set to things to
// items larger than what CanSSA would allow (approximateky, we disallow things
// marked as open defer slots so as to avoid complicating liveness
// analysis.
func IsMergeCandidate(n *ir.Name) bool {
if base.Debug.MergeLocals == 0 ||
base.Flag.N != 0 ||
n.Class != ir.PAUTO ||
n.Type().Size() <= int64(3*types.PtrSize) ||
n.Addrtaken() ||
n.NonMergeable() ||
n.OpenDeferSlot() {
return false
}
return true
} }

69
src/cmd/compile/internal/ssagen/pgen.go
View File

@ -13,7 +13,6 @@ import (
"cmd/compile/internal/base" "cmd/compile/internal/base"
"cmd/compile/internal/ir" "cmd/compile/internal/ir"
"cmd/compile/internal/liveness"
"cmd/compile/internal/objw" "cmd/compile/internal/objw"
"cmd/compile/internal/ssa" "cmd/compile/internal/ssa"
"cmd/compile/internal/types" "cmd/compile/internal/types"
@ -152,18 +151,6 @@ func (s *ssafn) AllocFrame(f *ssa.Func) {
} }
} }
var mls *liveness.MergeLocalsState
if base.Debug.MergeLocals != 0 {
mls = liveness.MergeLocals(fn, f)
if base.Debug.MergeLocalsTrace == 1 && mls != nil {
fmt.Fprintf(os.Stderr, "%s: %d bytes of stack space saved via stack slot merging\n", ir.FuncName(fn), mls.EstSavings())
if base.Debug.MergeLocalsTrace > 1 {
fmt.Fprintf(os.Stderr, "=-= merge locals state for %v:\n%v",
fn, mls)
}
}
}
// Use sort.SliceStable instead of sort.Slice so stack layout (and thus // Use sort.SliceStable instead of sort.Slice so stack layout (and thus
// compiler output) is less sensitive to frontend changes that // compiler output) is less sensitive to frontend changes that
// introduce or remove unused variables. // introduce or remove unused variables.
@ -171,22 +158,6 @@ func (s *ssafn) AllocFrame(f *ssa.Func) {
return cmpstackvarlt(fn.Dcl[i], fn.Dcl[j]) return cmpstackvarlt(fn.Dcl[i], fn.Dcl[j])
}) })
if base.Debug.MergeLocalsTrace > 1 && mls != nil {
fmt.Fprintf(os.Stderr, "=-= sorted DCL for %v:\n", fn)
for i, v := range fn.Dcl {
if !ssa.IsMergeCandidate(v) {
continue
}
fmt.Fprintf(os.Stderr, " %d: %q isleader=%v subsumed=%v used=%v\n", i, v.Sym().Name, mls.IsLeader(v), mls.Subsumed(v), v.Used())
}
}
var leaders map[*ir.Name]int64
if mls != nil {
leaders = make(map[*ir.Name]int64)
}
// Reassign stack offsets of the locals that are used. // Reassign stack offsets of the locals that are used.
lastHasPtr := false lastHasPtr := false
for i, n := range fn.Dcl { for i, n := range fn.Dcl {
@ -194,14 +165,12 @@ func (s *ssafn) AllocFrame(f *ssa.Func) {
// i.e., stack assign if AUTO, or if PARAMOUT in registers (which has no predefined spill locations) // i.e., stack assign if AUTO, or if PARAMOUT in registers (which has no predefined spill locations)
continue continue
} }
if mls != nil && mls.Subsumed(n) {
continue
}
if !n.Used() { if !n.Used() {
fn.DebugInfo.(*ssa.FuncDebug).OptDcl = fn.Dcl[i:] fn.DebugInfo.(*ssa.FuncDebug).OptDcl = fn.Dcl[i:]
fn.Dcl = fn.Dcl[:i] fn.Dcl = fn.Dcl[:i]
break break
} }
types.CalcSize(n.Type()) types.CalcSize(n.Type())
w := n.Type().Size() w := n.Type().Size()
if w >= types.MaxWidth || w < 0 { if w >= types.MaxWidth || w < 0 {
@ -226,42 +195,6 @@ func (s *ssafn) AllocFrame(f *ssa.Func) {
lastHasPtr = false lastHasPtr = false
} }
n.SetFrameOffset(-s.stksize) n.SetFrameOffset(-s.stksize)
if mls != nil && mls.IsLeader(n) {
leaders[n] = -s.stksize
}
}
if mls != nil {
followers := []*ir.Name{}
newdcl := make([]*ir.Name, 0, len(fn.Dcl))
for i := 0; i < len(fn.Dcl); i++ {
n := fn.Dcl[i]
if mls.Subsumed(n) {
continue
}
newdcl = append(newdcl, n)
if off, ok := leaders[n]; ok {
followers = mls.Followers(n, followers)
for _, f := range followers {
// Set the stack offset for each follower to be
// the same as the leader.
f.SetFrameOffset(off)
}
// position followers immediately after leader
newdcl = append(newdcl, followers...)
}
}
fn.Dcl = newdcl
}
if base.Debug.MergeLocalsTrace > 1 {
fmt.Fprintf(os.Stderr, "=-= stack layout for %v:\n", fn)
for i, v := range fn.Dcl {
if v.Op() != ir.ONAME || (v.Class != ir.PAUTO && !(v.Class == ir.PPARAMOUT && v.IsOutputParamInRegisters())) {
continue
}
fmt.Fprintf(os.Stderr, " %d: %q frameoff %d used=%v\n", i, v.Sym().Name, v.FrameOffset(), v.Used())
}
} }
s.stksize = types.RoundUp(s.stksize, s.stkalign) s.stksize = types.RoundUp(s.stksize, s.stkalign)

9
src/cmd/compile/internal/ssagen/ssa.go
View File

@ -633,7 +633,7 @@ func (s *state) zeroResults() {
if typ := n.Type(); ssa.CanSSA(typ) { if typ := n.Type(); ssa.CanSSA(typ) {
s.assign(n, s.zeroVal(typ), false, 0) s.assign(n, s.zeroVal(typ), false, 0)
} else { } else {
if typ.HasPointers() || ssa.IsMergeCandidate(n) { if typ.HasPointers() {
s.vars[memVar] = s.newValue1A(ssa.OpVarDef, types.TypeMem, n, s.mem()) s.vars[memVar] = s.newValue1A(ssa.OpVarDef, types.TypeMem, n, s.mem())
} }
s.zero(n.Type(), s.decladdrs[n]) s.zero(n.Type(), s.decladdrs[n])
@ -3942,7 +3942,7 @@ func (s *state) assignWhichMayOverlap(left ir.Node, right *ssa.Value, deref bool
// If this assignment clobbers an entire local variable, then emit // If this assignment clobbers an entire local variable, then emit
// OpVarDef so liveness analysis knows the variable is redefined. // OpVarDef so liveness analysis knows the variable is redefined.
if base, ok := clobberBase(left).(*ir.Name); ok && base.OnStack() && skip == 0 && (t.HasPointers() || ssa.IsMergeCandidate(base)) { if base, ok := clobberBase(left).(*ir.Name); ok && base.OnStack() && skip == 0 && t.HasPointers() {
s.vars[memVar] = s.newValue1Apos(ssa.OpVarDef, types.TypeMem, base, s.mem(), !ir.IsAutoTmp(base)) s.vars[memVar] = s.newValue1Apos(ssa.OpVarDef, types.TypeMem, base, s.mem(), !ir.IsAutoTmp(base))
} }
@ -5382,8 +5382,7 @@ func (s *state) call(n *ir.CallExpr, k callKind, returnResultAddr bool, deferExt
} }
// Make a defer struct on the stack. // Make a defer struct on the stack.
t := deferstruct() t := deferstruct()
n, addr := s.temp(n.Pos(), t) _, addr := s.temp(n.Pos(), t)
n.SetNonMergeable(true)
s.store(closure.Type, s.store(closure.Type,
s.newValue1I(ssa.OpOffPtr, closure.Type.PtrTo(), t.FieldOff(deferStructFnField), addr), s.newValue1I(ssa.OpOffPtr, closure.Type.PtrTo(), t.FieldOff(deferStructFnField), addr),
closure) closure)
@ -6887,7 +6886,7 @@ func (s *state) dottype1(pos src.XPos, src, dst *types.Type, iface, source, targ
// temp allocates a temp of type t at position pos // temp allocates a temp of type t at position pos
func (s *state) temp(pos src.XPos, t *types.Type) (*ir.Name, *ssa.Value) { func (s *state) temp(pos src.XPos, t *types.Type) (*ir.Name, *ssa.Value) {
tmp := typecheck.TempAt(pos, s.curfn, t) tmp := typecheck.TempAt(pos, s.curfn, t)
if t.HasPointers() || (ssa.IsMergeCandidate(tmp) && t != deferstruct()) { if t.HasPointers() {
s.vars[memVar] = s.newValue1A(ssa.OpVarDef, types.TypeMem, tmp, s.mem()) s.vars[memVar] = s.newValue1A(ssa.OpVarDef, types.TypeMem, tmp, s.mem())
} }
addr := s.addr(tmp) addr := s.addr(tmp)

184
src/cmd/compile/internal/test/mergelocals_test.go
View File

@ -1,184 +0,0 @@
// Copyright 2024 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 test
import (
"cmd/compile/internal/ir"
"cmd/compile/internal/liveness"
"cmd/compile/internal/typecheck"
"cmd/compile/internal/types"
"cmd/internal/src"
"internal/testenv"
"path/filepath"
"slices"
"sort"
"strings"
"testing"
)
func TestMergeLocalState(t *testing.T) {
mkiv := func(name string) *ir.Name {
i32 := types.Types[types.TINT32]
s := typecheck.Lookup(name)
v := ir.NewNameAt(src.NoXPos, s, i32)
return v
}
v1 := mkiv("v1")
v2 := mkiv("v2")
v3 := mkiv("v3")
testcases := []struct {
vars []*ir.Name
partition map[*ir.Name][]int
experr bool
}{
{
vars: []*ir.Name{v1, v2, v3},
partition: map[*ir.Name][]int{
v1: []int{0, 1, 2},
v2: []int{0, 1, 2},
v3: []int{0, 1, 2},
},
experr: false,
},
{
// invalid mls.v slot -1
vars: []*ir.Name{v1, v2, v3},
partition: map[*ir.Name][]int{
v1: []int{-1, 0},
v2: []int{0, 1, 2},
v3: []int{0, 1, 2},
},
experr: true,
},
{
// duplicate var in v
vars: []*ir.Name{v1, v2, v2},
partition: map[*ir.Name][]int{
v1: []int{0, 1, 2},
v2: []int{0, 1, 2},
v3: []int{0, 1, 2},
},
experr: true,
},
{
// single element in partition
vars: []*ir.Name{v1, v2, v3},
partition: map[*ir.Name][]int{
v1: []int{0},
v2: []int{0, 1, 2},
v3: []int{0, 1, 2},
},
experr: true,
},
{
// missing element 2
vars: []*ir.Name{v1, v2, v3},
partition: map[*ir.Name][]int{
v1: []int{0, 1},
v2: []int{0, 1},
v3: []int{0, 1},
},
experr: true,
},
{
// partitions disagree for v1 vs v2
vars: []*ir.Name{v1, v2, v3},
partition: map[*ir.Name][]int{
v1: []int{0, 1, 2},
v2: []int{1, 0, 2},
v3: []int{0, 1, 2},
},
experr: true,
},
}
for k, testcase := range testcases {
mls, err := liveness.MakeMergeLocalsState(testcase.partition, testcase.vars)
t.Logf("tc %d err is %v\n", k, err)
if testcase.experr && err == nil {
t.Fatalf("tc:%d missing error mls %v", k, mls)
} else if !testcase.experr && err != nil {
t.Fatalf("tc:%d unexpected error mls %v", k, err)
}
if mls != nil {
t.Logf("tc %d: mls: %v\n", k, mls.String())
}
}
}
func TestMergeLocalsIntegration(t *testing.T) {
testenv.MustHaveGoBuild(t)
// This test does a build of a specific canned package to
// check whether merging of stack slots is taking place.
// The idea is to do the compile with a trace option turned
// on and then pick up on the frame offsets of specific
// variables.
//
// Stack slot merging is a greedy algorithm, and there can
// be many possible ways to overlap a given set of candidate
// variables, all of them legal. Rather than locking down
// a specific set of overlappings or frame offsets, this
// tests just verifies that there is one clump of 3 vars that
// get overlapped, then another clump of 2 that share the same
// frame offset.
//
// The expected output blob we're interested in looks like this:
//
// =-= stack layout for ABC:
// 2: "p1" frameoff -8200 used=true
// 3: "xp3" frameoff -8200 used=true
// 4: "xp4" frameoff -8200 used=true
// 5: "p2" frameoff -16400 used=true
// 6: "s" frameoff -24592 used=true
// 7: "v1" frameoff -32792 used=true
// 8: "v3" frameoff -32792 used=true
// 9: "v2" frameoff -40992 used=true
//
tmpdir := t.TempDir()
src := filepath.Join("testdata", "mergelocals", "integration.go")
obj := filepath.Join(tmpdir, "p.a")
out, err := testenv.Command(t, testenv.GoToolPath(t), "tool", "compile", "-p=p", "-c", "1", "-o", obj, "-d=mergelocalstrace=2,mergelocals=1", src).CombinedOutput()
if err != nil {
t.Fatalf("failed to compile: %v\n%s", err, out)
}
vars := make(map[string]string)
lines := strings.Split(string(out), "\n")
prolog := true
varsAtFrameOffset := make(map[string]int)
for _, line := range lines {
if line == "=-= stack layout for ABC:" {
prolog = false
continue
} else if prolog || line == "" {
continue
}
fields := strings.Fields(line)
if len(fields) != 5 {
t.Fatalf("bad trace output line: %s", line)
}
vname := fields[1]
frameoff := fields[3]
varsAtFrameOffset[frameoff] = varsAtFrameOffset[frameoff] + 1
vars[vname] = frameoff
}
wantvnum := 8
gotvnum := len(vars)
if wantvnum != gotvnum {
t.Fatalf("expected trace output on %d vars got %d\n", wantvnum, gotvnum)
}
// We expect one clump of 3, another clump of 2, and the rest singletons.
expected := []int{1, 1, 1, 2, 3}
got := []int{}
for _, v := range varsAtFrameOffset {
got = append(got, v)
}
sort.Ints(got)
if !slices.Equal(got, expected) {
t.Fatalf("expected variable clumps %+v not equal to what we got: %+v", expected, got)
}
}

83
src/cmd/compile/internal/test/testdata/mergelocals/integration.go vendored
View File

@ -1,83 +0,0 @@
// Copyright 2024 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 p
// This type and the following one will share the same GC shape and size.
type Pointery struct {
p *Pointery
x [1024]int
}
type Pointery2 struct {
p *Pointery2
x [1024]int
}
// This type and the following one will have the same size.
type Vanilla struct {
np uintptr
x [1024]int
}
type Vanilla2 struct {
np uintptr
x [1023]int
y int
}
type Single struct {
np uintptr
x [1023]int
}
func ABC(i, j int) int {
r := 0
// here v1 interferes with v2 but could be overlapped with v3.
// we can also overlap v1 with v3.
var v1 Vanilla
if i < 101 {
var v2 Vanilla
v1.x[i] = j
r += v1.x[j]
v2.x[i] = j
r += v2.x[j]
}
{
var v3 Vanilla2
v3.x[i] = j
r += v3.x[j]
}
var s Single
s.x[i] = j
r += s.x[j]
// Here p1 and p2 interfere, but p1 could be overlapped with xp3.
var p1, p2 Pointery
p1.x[i] = j
r += p1.x[j]
p2.x[i] = j
r += p2.x[j]
{
var xp3 Pointery2
xp3.x[i] = j
r += xp3.x[j]
}
if i == j*2 {
// p2 live on this path
p2.x[i] += j
r += p2.x[j]
} else {
// p2 not live on this path
var xp4 Pointery2
xp4.x[i] = j
r += xp4.x[j]
}
return r
}

4
src/cmd/compile/internal/walk/temp.go
View File

@ -25,9 +25,7 @@ func initStackTemp(init *ir.Nodes, tmp *ir.Name, val ir.Node) *ir.AddrExpr {
// allocated temporary variable of the given type. Statements to // allocated temporary variable of the given type. Statements to
// zero-initialize tmp are appended to init. // zero-initialize tmp are appended to init.
func stackTempAddr(init *ir.Nodes, typ *types.Type) *ir.AddrExpr { func stackTempAddr(init *ir.Nodes, typ *types.Type) *ir.AddrExpr {
n := typecheck.TempAt(base.Pos, ir.CurFunc, typ) return initStackTemp(init, typecheck.TempAt(base.Pos, ir.CurFunc, typ), nil)
n.SetNonMergeable(true)
return initStackTemp(init, n, nil)
} }
// stackBufAddr returns the expression &tmp, where tmp is a newly // stackBufAddr returns the expression &tmp, where tmp is a newly

625
test/fixedbugs/bug385_64.go
View File

@ -11,423 +11,214 @@
package main package main
var z [10 << 20]byte var z [10<<20]byte
func main() { // GC_ERROR "stack frame too large" func main() { // GC_ERROR "stack frame too large"
// seq 1 206 | sed 's/.*/ var x& [10<<20]byte/' // seq 1 206 | sed 's/.*/ var x& [10<<20]byte; z = x&/'
// seq 1 206 | sed 's/.*/ z = x&/' var x1 [10<<20]byte; z = x1
var x1 [10<<20]byte var x2 [10<<20]byte; z = x2
var x2 [10<<20]byte var x3 [10<<20]byte; z = x3
var x3 [10<<20]byte var x4 [10<<20]byte; z = x4
var x4 [10<<20]byte var x5 [10<<20]byte; z = x5
var x5 [10<<20]byte var x6 [10<<20]byte; z = x6
var x6 [10<<20]byte var x7 [10<<20]byte; z = x7
var x7 [10<<20]byte var x8 [10<<20]byte; z = x8
var x8 [10<<20]byte var x9 [10<<20]byte; z = x9
var x9 [10<<20]byte var x10 [10<<20]byte; z = x10
var x10 [10<<20]byte var x11 [10<<20]byte; z = x11
var x11 [10<<20]byte var x12 [10<<20]byte; z = x12
var x12 [10<<20]byte var x13 [10<<20]byte; z = x13
var x13 [10<<20]byte var x14 [10<<20]byte; z = x14
var x14 [10<<20]byte var x15 [10<<20]byte; z = x15
var x15 [10<<20]byte var x16 [10<<20]byte; z = x16
var x16 [10<<20]byte var x17 [10<<20]byte; z = x17
var x17 [10<<20]byte var x18 [10<<20]byte; z = x18
var x18 [10<<20]byte var x19 [10<<20]byte; z = x19
var x19 [10<<20]byte var x20 [10<<20]byte; z = x20
var x20 [10<<20]byte var x21 [10<<20]byte; z = x21
var x21 [10<<20]byte var x22 [10<<20]byte; z = x22
var x22 [10<<20]byte var x23 [10<<20]byte; z = x23
var x23 [10<<20]byte var x24 [10<<20]byte; z = x24
var x24 [10<<20]byte var x25 [10<<20]byte; z = x25
var x25 [10<<20]byte var x26 [10<<20]byte; z = x26
var x26 [10<<20]byte var x27 [10<<20]byte; z = x27
var x27 [10<<20]byte var x28 [10<<20]byte; z = x28
var x28 [10<<20]byte var x29 [10<<20]byte; z = x29
var x29 [10<<20]byte var x30 [10<<20]byte; z = x30
var x30 [10<<20]byte var x31 [10<<20]byte; z = x31
var x31 [10<<20]byte var x32 [10<<20]byte; z = x32
var x32 [10<<20]byte var x33 [10<<20]byte; z = x33
var x33 [10<<20]byte var x34 [10<<20]byte; z = x34
var x34 [10<<20]byte var x35 [10<<20]byte; z = x35
var x35 [10<<20]byte var x36 [10<<20]byte; z = x36
var x36 [10<<20]byte var x37 [10<<20]byte; z = x37
var x37 [10<<20]byte var x38 [10<<20]byte; z = x38
var x38 [10<<20]byte var x39 [10<<20]byte; z = x39
var x39 [10<<20]byte var x40 [10<<20]byte; z = x40
var x40 [10<<20]byte var x41 [10<<20]byte; z = x41
var x41 [10<<20]byte var x42 [10<<20]byte; z = x42
var x42 [10<<20]byte var x43 [10<<20]byte; z = x43
var x43 [10<<20]byte var x44 [10<<20]byte; z = x44
var x44 [10<<20]byte var x45 [10<<20]byte; z = x45
var x45 [10<<20]byte var x46 [10<<20]byte; z = x46
var x46 [10<<20]byte var x47 [10<<20]byte; z = x47
var x47 [10<<20]byte var x48 [10<<20]byte; z = x48
var x48 [10<<20]byte var x49 [10<<20]byte; z = x49
var x49 [10<<20]byte var x50 [10<<20]byte; z = x50
var x50 [10<<20]byte var x51 [10<<20]byte; z = x51
var x51 [10<<20]byte var x52 [10<<20]byte; z = x52
var x52 [10<<20]byte var x53 [10<<20]byte; z = x53
var x53 [10<<20]byte var x54 [10<<20]byte; z = x54
var x54 [10<<20]byte var x55 [10<<20]byte; z = x55
var x55 [10<<20]byte var x56 [10<<20]byte; z = x56
var x56 [10<<20]byte var x57 [10<<20]byte; z = x57
var x57 [10<<20]byte var x58 [10<<20]byte; z = x58
var x58 [10<<20]byte var x59 [10<<20]byte; z = x59
var x59 [10<<20]byte var x60 [10<<20]byte; z = x60
var x60 [10<<20]byte var x61 [10<<20]byte; z = x61
var x61 [10<<20]byte var x62 [10<<20]byte; z = x62
var x62 [10<<20]byte var x63 [10<<20]byte; z = x63
var x63 [10<<20]byte var x64 [10<<20]byte; z = x64
var x64 [10<<20]byte var x65 [10<<20]byte; z = x65
var x65 [10<<20]byte var x66 [10<<20]byte; z = x66
var x66 [10<<20]byte var x67 [10<<20]byte; z = x67
var x67 [10<<20]byte var x68 [10<<20]byte; z = x68
var x68 [10<<20]byte var x69 [10<<20]byte; z = x69
var x69 [10<<20]byte var x70 [10<<20]byte; z = x70
var x70 [10<<20]byte var x71 [10<<20]byte; z = x71
var x71 [10<<20]byte var x72 [10<<20]byte; z = x72
var x72 [10<<20]byte var x73 [10<<20]byte; z = x73
var x73 [10<<20]byte var x74 [10<<20]byte; z = x74
var x74 [10<<20]byte var x75 [10<<20]byte; z = x75
var x75 [10<<20]byte var x76 [10<<20]byte; z = x76
var x76 [10<<20]byte var x77 [10<<20]byte; z = x77
var x77 [10<<20]byte var x78 [10<<20]byte; z = x78
var x78 [10<<20]byte var x79 [10<<20]byte; z = x79
var x79 [10<<20]byte var x80 [10<<20]byte; z = x80
var x80 [10<<20]byte var x81 [10<<20]byte; z = x81
var x81 [10<<20]byte var x82 [10<<20]byte; z = x82
var x82 [10<<20]byte var x83 [10<<20]byte; z = x83
var x83 [10<<20]byte var x84 [10<<20]byte; z = x84
var x84 [10<<20]byte var x85 [10<<20]byte; z = x85
var x85 [10<<20]byte var x86 [10<<20]byte; z = x86
var x86 [10<<20]byte var x87 [10<<20]byte; z = x87
var x87 [10<<20]byte var x88 [10<<20]byte; z = x88
var x88 [10<<20]byte var x89 [10<<20]byte; z = x89
var x89 [10<<20]byte var x90 [10<<20]byte; z = x90
var x90 [10<<20]byte var x91 [10<<20]byte; z = x91
var x91 [10<<20]byte var x92 [10<<20]byte; z = x92
var x92 [10<<20]byte var x93 [10<<20]byte; z = x93
var x93 [10<<20]byte var x94 [10<<20]byte; z = x94
var x94 [10<<20]byte var x95 [10<<20]byte; z = x95
var x95 [10<<20]byte var x96 [10<<20]byte; z = x96
var x96 [10<<20]byte var x97 [10<<20]byte; z = x97
var x97 [10<<20]byte var x98 [10<<20]byte; z = x98
var x98 [10<<20]byte var x99 [10<<20]byte; z = x99
var x99 [10<<20]byte var x100 [10<<20]byte; z = x100
var x100 [10<<20]byte var x101 [10<<20]byte; z = x101
var x101 [10<<20]byte var x102 [10<<20]byte; z = x102
var x102 [10<<20]byte var x103 [10<<20]byte; z = x103
var x103 [10<<20]byte var x104 [10<<20]byte; z = x104
var x104 [10<<20]byte var x105 [10<<20]byte; z = x105
var x105 [10<<20]byte var x106 [10<<20]byte; z = x106
var x106 [10<<20]byte var x107 [10<<20]byte; z = x107
var x107 [10<<20]byte var x108 [10<<20]byte; z = x108
var x108 [10<<20]byte var x109 [10<<20]byte; z = x109
var x109 [10<<20]byte var x110 [10<<20]byte; z = x110
var x110 [10<<20]byte var x111 [10<<20]byte; z = x111
var x111 [10<<20]byte var x112 [10<<20]byte; z = x112
var x112 [10<<20]byte var x113 [10<<20]byte; z = x113
var x113 [10<<20]byte var x114 [10<<20]byte; z = x114
var x114 [10<<20]byte var x115 [10<<20]byte; z = x115
var x115 [10<<20]byte var x116 [10<<20]byte; z = x116
var x116 [10<<20]byte var x117 [10<<20]byte; z = x117
var x117 [10<<20]byte var x118 [10<<20]byte; z = x118
var x118 [10<<20]byte var x119 [10<<20]byte; z = x119
var x119 [10<<20]byte var x120 [10<<20]byte; z = x120
var x120 [10<<20]byte var x121 [10<<20]byte; z = x121
var x121 [10<<20]byte var x122 [10<<20]byte; z = x122
var x122 [10<<20]byte var x123 [10<<20]byte; z = x123
var x123 [10<<20]byte var x124 [10<<20]byte; z = x124
var x124 [10<<20]byte var x125 [10<<20]byte; z = x125
var x125 [10<<20]byte var x126 [10<<20]byte; z = x126
var x126 [10<<20]byte var x127 [10<<20]byte; z = x127
var x127 [10<<20]byte var x128 [10<<20]byte; z = x128
var x128 [10<<20]byte var x129 [10<<20]byte; z = x129
var x129 [10<<20]byte var x130 [10<<20]byte; z = x130
var x130 [10<<20]byte var x131 [10<<20]byte; z = x131
var x131 [10<<20]byte var x132 [10<<20]byte; z = x132
var x132 [10<<20]byte var x133 [10<<20]byte; z = x133
var x133 [10<<20]byte var x134 [10<<20]byte; z = x134
var x134 [10<<20]byte var x135 [10<<20]byte; z = x135
var x135 [10<<20]byte var x136 [10<<20]byte; z = x136
var x136 [10<<20]byte var x137 [10<<20]byte; z = x137
var x137 [10<<20]byte var x138 [10<<20]byte; z = x138
var x138 [10<<20]byte var x139 [10<<20]byte; z = x139
var x139 [10<<20]byte var x140 [10<<20]byte; z = x140
var x140 [10<<20]byte var x141 [10<<20]byte; z = x141
var x141 [10<<20]byte var x142 [10<<20]byte; z = x142
var x142 [10<<20]byte var x143 [10<<20]byte; z = x143
var x143 [10<<20]byte var x144 [10<<20]byte; z = x144
var x144 [10<<20]byte var x145 [10<<20]byte; z = x145
var x145 [10<<20]byte var x146 [10<<20]byte; z = x146
var x146 [10<<20]byte var x147 [10<<20]byte; z = x147
var x147 [10<<20]byte var x148 [10<<20]byte; z = x148
var x148 [10<<20]byte var x149 [10<<20]byte; z = x149
var x149 [10<<20]byte var x150 [10<<20]byte; z = x150
var x150 [10<<20]byte var x151 [10<<20]byte; z = x151
var x151 [10<<20]byte var x152 [10<<20]byte; z = x152
var x152 [10<<20]byte var x153 [10<<20]byte; z = x153
var x153 [10<<20]byte var x154 [10<<20]byte; z = x154
var x154 [10<<20]byte var x155 [10<<20]byte; z = x155
var x155 [10<<20]byte var x156 [10<<20]byte; z = x156
var x156 [10<<20]byte var x157 [10<<20]byte; z = x157
var x157 [10<<20]byte var x158 [10<<20]byte; z = x158
var x158 [10<<20]byte var x159 [10<<20]byte; z = x159
var x159 [10<<20]byte var x160 [10<<20]byte; z = x160
var x160 [10<<20]byte var x161 [10<<20]byte; z = x161
var x161 [10<<20]byte var x162 [10<<20]byte; z = x162
var x162 [10<<20]byte var x163 [10<<20]byte; z = x163
var x163 [10<<20]byte var x164 [10<<20]byte; z = x164
var x164 [10<<20]byte var x165 [10<<20]byte; z = x165
var x165 [10<<20]byte var x166 [10<<20]byte; z = x166
var x166 [10<<20]byte var x167 [10<<20]byte; z = x167
var x167 [10<<20]byte var x168 [10<<20]byte; z = x168
var x168 [10<<20]byte var x169 [10<<20]byte; z = x169
var x169 [10<<20]byte var x170 [10<<20]byte; z = x170
var x170 [10<<20]byte var x171 [10<<20]byte; z = x171
var x171 [10<<20]byte var x172 [10<<20]byte; z = x172
var x172 [10<<20]byte var x173 [10<<20]byte; z = x173
var x173 [10<<20]byte var x174 [10<<20]byte; z = x174
var x174 [10<<20]byte var x175 [10<<20]byte; z = x175
var x175 [10<<20]byte var x176 [10<<20]byte; z = x176
var x176 [10<<20]byte var x177 [10<<20]byte; z = x177
var x177 [10<<20]byte var x178 [10<<20]byte; z = x178
var x178 [10<<20]byte var x179 [10<<20]byte; z = x179
var x179 [10<<20]byte var x180 [10<<20]byte; z = x180
var x180 [10<<20]byte var x181 [10<<20]byte; z = x181
var x181 [10<<20]byte var x182 [10<<20]byte; z = x182
var x182 [10<<20]byte var x183 [10<<20]byte; z = x183
var x183 [10<<20]byte var x184 [10<<20]byte; z = x184
var x184 [10<<20]byte var x185 [10<<20]byte; z = x185
var x185 [10<<20]byte var x186 [10<<20]byte; z = x186
var x186 [10<<20]byte var x187 [10<<20]byte; z = x187
var x187 [10<<20]byte var x188 [10<<20]byte; z = x188
var x188 [10<<20]byte var x189 [10<<20]byte; z = x189
var x189 [10<<20]byte var x190 [10<<20]byte; z = x190
var x190 [10<<20]byte var x191 [10<<20]byte; z = x191
var x191 [10<<20]byte var x192 [10<<20]byte; z = x192
var x192 [10<<20]byte var x193 [10<<20]byte; z = x193
var x193 [10<<20]byte var x194 [10<<20]byte; z = x194
var x194 [10<<20]byte var x195 [10<<20]byte; z = x195
var x195 [10<<20]byte var x196 [10<<20]byte; z = x196
var x196 [10<<20]byte var x197 [10<<20]byte; z = x197
var x197 [10<<20]byte var x198 [10<<20]byte; z = x198
var x198 [10<<20]byte var x199 [10<<20]byte; z = x199
var x199 [10<<20]byte var x200 [10<<20]byte; z = x200
var x200 [10<<20]byte var x201 [10<<20]byte; z = x201
var x201 [10<<20]byte var x202 [10<<20]byte; z = x202
var x202 [10<<20]byte var x203 [10<<20]byte; z = x203
var x203 [10<<20]byte var x204 [10<<20]byte; z = x204
var x204 [10<<20]byte var x205 [10<<20]byte; z = x205
var x205 [10<<20]byte var x206 [10<<20]byte; z = x206
var x206 [10<<20]byte
var x207 [10<<20]byte
z = x1
z = x2
z = x3
z = x4
z = x5
z = x6
z = x7
z = x8
z = x9
z = x10
z = x11
z = x12
z = x13
z = x14
z = x15
z = x16
z = x17
z = x18
z = x19
z = x20
z = x21
z = x22
z = x23
z = x24
z = x25
z = x26
z = x27
z = x28
z = x29
z = x30
z = x31
z = x32
z = x33
z = x34
z = x35
z = x36
z = x37
z = x38
z = x39
z = x40
z = x41
z = x42
z = x43
z = x44
z = x45
z = x46
z = x47
z = x48
z = x49
z = x50
z = x51
z = x52
z = x53
z = x54
z = x55
z = x56
z = x57
z = x58
z = x59
z = x60
z = x61
z = x62
z = x63
z = x64
z = x65
z = x66
z = x67
z = x68
z = x69
z = x70
z = x71
z = x72
z = x73
z = x74
z = x75
z = x76
z = x77
z = x78
z = x79
z = x80
z = x81
z = x82
z = x83
z = x84
z = x85
z = x86
z = x87
z = x88
z = x89
z = x90
z = x91
z = x92
z = x93
z = x94
z = x95
z = x96
z = x97
z = x98
z = x99
z = x100
z = x101
z = x102
z = x103
z = x104
z = x105
z = x106
z = x107
z = x108
z = x109
z = x110
z = x111
z = x112
z = x113
z = x114
z = x115
z = x116
z = x117
z = x118
z = x119
z = x120
z = x121
z = x122
z = x123
z = x124
z = x125
z = x126
z = x127
z = x128
z = x129
z = x130
z = x131
z = x132
z = x133
z = x134
z = x135
z = x136
z = x137
z = x138
z = x139
z = x140
z = x141
z = x142
z = x143
z = x144
z = x145
z = x146
z = x147
z = x148
z = x149
z = x150
z = x151
z = x152
z = x153
z = x154
z = x155
z = x156
z = x157
z = x158
z = x159
z = x160
z = x161
z = x162
z = x163
z = x164
z = x165
z = x166
z = x167
z = x168
z = x169
z = x170
z = x171
z = x172
z = x173
z = x174
z = x175
z = x176
z = x177
z = x178
z = x179
z = x180
z = x181
z = x182
z = x183
z = x184
z = x185
z = x186
z = x187
z = x188
z = x189
z = x190
z = x191
z = x192
z = x193
z = x194
z = x195
z = x196
z = x197
z = x198
z = x199
z = x200
z = x201
z = x202
z = x203
z = x204
z = x205
z = x206
z = x207
} }