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cmd/compile,runtime: remove ambiguously live logic

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The previous CL introduced stack objects. This CL removes the old
ambiguously live liveness analysis. After this CL we're relying
on stack objects exclusively.

Update a bunch of liveness tests to reflect the new world.

Fixes #22350

Change-Id: I739b26e015882231011ce6bc1a7f426049e59f31
Reviewed-on: https://go-review.googlesource.com/c/134156
Reviewed-by: Austin Clements <austin@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
This commit is contained in:
Keith Randall 2018-09-07 14:55:09 -07:00 committed by Keith Randall
parent cbafcc55e8
commit 9a8372f8bd
16 changed files with 375 additions and 334 deletions
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4
src/cmd/compile/internal/gc/op_string.go
View File

@ -4,9 +4,9 @@ package gc
import "strconv" import "strconv"
const _Op_name = "XXXNAMENONAMETYPEPACKLITERALADDSUBORXORADDSTRADDRANDANDAPPENDARRAYBYTESTRARRAYBYTESTRTMPARRAYRUNESTRSTRARRAYBYTESTRARRAYBYTETMPSTRARRAYRUNEASAS2AS2FUNCAS2RECVAS2MAPRAS2DOTTYPEASOPCALLCALLFUNCCALLMETHCALLINTERCALLPARTCAPCLOSECLOSURECMPIFACECMPSTRCOMPLITMAPLITSTRUCTLITARRAYLITSLICELITPTRLITCONVCONVIFACECONVNOPCOPYDCLDCLFUNCDCLFIELDDCLCONSTDCLTYPEDELETEDOTDOTPTRDOTMETHDOTINTERXDOTDOTTYPEDOTTYPE2EQNELTLEGEGTINDINDEXINDEXMAPKEYSTRUCTKEYLENMAKEMAKECHANMAKEMAPMAKESLICEMULDIVMODLSHRSHANDANDNOTNEWNOTCOMPLUSMINUSORORPANICPRINTPRINTNPARENSENDSLICESLICEARRSLICESTRSLICE3SLICE3ARRRECOVERRECVRUNESTRSELRECVSELRECV2IOTAREALIMAGCOMPLEXALIGNOFOFFSETOFSIZEOFBLOCKBREAKCASEXCASECONTINUEDEFEREMPTYFALLFORFORUNTILGOTOIFLABELPROCRANGERETURNSELECTSWITCHTYPESWTCHANTMAPTSTRUCTTINTERTFUNCTARRAYDDDDDDARGINLCALLEFACEITABIDATASPTRCLOSUREVARCFUNCCHECKNILVARKILLVARLIVEINDREGSPRETJMPGETGEND" const _Op_name = "XXXNAMENONAMETYPEPACKLITERALADDSUBORXORADDSTRADDRANDANDAPPENDARRAYBYTESTRARRAYBYTESTRTMPARRAYRUNESTRSTRARRAYBYTESTRARRAYBYTETMPSTRARRAYRUNEASAS2AS2FUNCAS2RECVAS2MAPRAS2DOTTYPEASOPCALLCALLFUNCCALLMETHCALLINTERCALLPARTCAPCLOSECLOSURECMPIFACECMPSTRCOMPLITMAPLITSTRUCTLITARRAYLITSLICELITPTRLITCONVCONVIFACECONVNOPCOPYDCLDCLFUNCDCLFIELDDCLCONSTDCLTYPEDELETEDOTDOTPTRDOTMETHDOTINTERXDOTDOTTYPEDOTTYPE2EQNELTLEGEGTINDINDEXINDEXMAPKEYSTRUCTKEYLENMAKEMAKECHANMAKEMAPMAKESLICEMULDIVMODLSHRSHANDANDNOTNEWNOTCOMPLUSMINUSORORPANICPRINTPRINTNPARENSENDSLICESLICEARRSLICESTRSLICE3SLICE3ARRRECOVERRECVRUNESTRSELRECVSELRECV2IOTAREALIMAGCOMPLEXALIGNOFOFFSETOFSIZEOFBLOCKBREAKCASEXCASECONTINUEDEFEREMPTYFALLFORFORUNTILGOTOIFLABELPROCRANGERETURNSELECTSWITCHTYPESWTCHANTMAPTSTRUCTTINTERTFUNCTARRAYDDDDDDARGINLCALLEFACEITABIDATASPTRCLOSUREVARCFUNCCHECKNILVARDEFVARKILLVARLIVEINDREGSPRETJMPGETGEND"
var _Op_index = [...]uint16{0, 3, 7, 13, 17, 21, 28, 31, 34, 36, 39, 45, 49, 55, 61, 73, 88, 100, 112, 127, 139, 141, 144, 151, 158, 165, 175, 179, 183, 191, 199, 208, 216, 219, 224, 231, 239, 245, 252, 258, 267, 275, 283, 289, 293, 302, 309, 313, 316, 323, 331, 339, 346, 352, 355, 361, 368, 376, 380, 387, 395, 397, 399, 401, 403, 405, 407, 410, 415, 423, 426, 435, 438, 442, 450, 457, 466, 469, 472, 475, 478, 481, 484, 490, 493, 496, 499, 503, 508, 512, 517, 522, 528, 533, 537, 542, 550, 558, 564, 573, 580, 584, 591, 598, 606, 610, 614, 618, 625, 632, 640, 646, 651, 656, 660, 665, 673, 678, 683, 687, 690, 698, 702, 704, 709, 713, 718, 724, 730, 736, 742, 747, 751, 758, 764, 769, 775, 778, 784, 791, 796, 800, 805, 809, 819, 824, 832, 839, 846, 854, 860, 864, 867} var _Op_index = [...]uint16{0, 3, 7, 13, 17, 21, 28, 31, 34, 36, 39, 45, 49, 55, 61, 73, 88, 100, 112, 127, 139, 141, 144, 151, 158, 165, 175, 179, 183, 191, 199, 208, 216, 219, 224, 231, 239, 245, 252, 258, 267, 275, 283, 289, 293, 302, 309, 313, 316, 323, 331, 339, 346, 352, 355, 361, 368, 376, 380, 387, 395, 397, 399, 401, 403, 405, 407, 410, 415, 423, 426, 435, 438, 442, 450, 457, 466, 469, 472, 475, 478, 481, 484, 490, 493, 496, 499, 503, 508, 512, 517, 522, 528, 533, 537, 542, 550, 558, 564, 573, 580, 584, 591, 598, 606, 610, 614, 618, 625, 632, 640, 646, 651, 656, 660, 665, 673, 678, 683, 687, 690, 698, 702, 704, 709, 713, 718, 724, 730, 736, 742, 747, 751, 758, 764, 769, 775, 778, 784, 791, 796, 800, 805, 809, 819, 824, 832, 838, 845, 852, 860, 866, 870, 873}
func (i Op) String() string { func (i Op) String() string {
if i >= Op(len(_Op_index)-1) { if i >= Op(len(_Op_index)-1) {

235
src/cmd/compile/internal/gc/plive.go
View File

@ -78,6 +78,10 @@ import (
// that its argument is certainly dead, for use when the liveness analysis // that its argument is certainly dead, for use when the liveness analysis
// would not otherwise be able to deduce that fact. // would not otherwise be able to deduce that fact.
// TODO: get rid of OpVarKill here. It's useful for stack frame allocation
// so the compiler can allocate two temps to the same location. Here it's now
// useless, since the implementation of stack objects.
// BlockEffects summarizes the liveness effects on an SSA block. // BlockEffects summarizes the liveness effects on an SSA block.
type BlockEffects struct { type BlockEffects struct {
// Computed during Liveness.prologue using only the content of // Computed during Liveness.prologue using only the content of
@ -85,23 +89,15 @@ type BlockEffects struct {
// //
// uevar: upward exposed variables (used before set in block) // uevar: upward exposed variables (used before set in block)
// varkill: killed variables (set in block) // varkill: killed variables (set in block)
// avarinit: addrtaken variables set or used (proof of initialization) uevar varRegVec
uevar varRegVec varkill varRegVec
varkill varRegVec
avarinit bvec
// Computed during Liveness.solve using control flow information: // Computed during Liveness.solve using control flow information:
// //
// livein: variables live at block entry // livein: variables live at block entry
// liveout: variables live at block exit // liveout: variables live at block exit
// avarinitany: addrtaken variables possibly initialized at block exit livein varRegVec
// (initialized in block or at exit from any predecessor block) liveout varRegVec
// avarinitall: addrtaken variables certainly initialized at block exit
// (initialized in block or at exit from all predecessor blocks)
livein varRegVec
liveout varRegVec
avarinitany bvec
avarinitall bvec
} }
// A collection of global state used by liveness analysis. // A collection of global state used by liveness analysis.
@ -186,10 +182,9 @@ func (idx LivenessIndex) Valid() bool {
} }
type progeffectscache struct { type progeffectscache struct {
textavarinit []int32 retuevar []int32
retuevar []int32 tailuevar []int32
tailuevar []int32 initialized bool
initialized bool
} }
// varRegVec contains liveness bitmaps for variables and registers. // varRegVec contains liveness bitmaps for variables and registers.
@ -264,24 +259,13 @@ func (lv *Liveness) initcache() {
// all the parameters for correctness, and similarly it must not // all the parameters for correctness, and similarly it must not
// read the out arguments - they won't be set until the new // read the out arguments - they won't be set until the new
// function runs. // function runs.
lv.cache.tailuevar = append(lv.cache.tailuevar, int32(i)) lv.cache.tailuevar = append(lv.cache.tailuevar, int32(i))
if node.Addrtaken() {
lv.cache.textavarinit = append(lv.cache.textavarinit, int32(i))
}
case PPARAMOUT: case PPARAMOUT:
// If the result had its address taken, it is being tracked // All results are live at every return point.
// by the avarinit code, which does not use uevar. // Note that this point is after escaping return values
// If we added it to uevar too, we'd not see any kill // are copied back to the stack using their PAUTOHEAP references.
// and decide that the variable was live entry, which it is not. lv.cache.retuevar = append(lv.cache.retuevar, int32(i))
// So only use uevar in the non-addrtaken case.
// The p.to.type == obj.TYPE_NONE limits the bvset to
// non-tail-call return instructions; see note below for details.
if !node.Addrtaken() {
lv.cache.retuevar = append(lv.cache.retuevar, int32(i))
}
} }
} }
} }
@ -291,21 +275,13 @@ func (lv *Liveness) initcache() {
// //
// The possible flags are: // The possible flags are:
// uevar - used by the instruction // uevar - used by the instruction
// varkill - killed by the instruction // varkill - killed by the instruction (set)
// for variables without address taken, means variable was set // A kill happens after the use (for an instruction that updates a value, for example).
// for variables with address taken, means variable was marked dead
// avarinit - initialized or referred to by the instruction,
// only for variables with address taken but not escaping to heap
//
// The avarinit output serves as a signal that the data has been
// initialized, because any use of a variable must come after its
// initialization.
type liveEffect int type liveEffect int
const ( const (
uevar liveEffect = 1 << iota uevar liveEffect = 1 << iota
varkill varkill
avarinit
) )
// valueEffects returns the index of a variable in lv.vars and the // valueEffects returns the index of a variable in lv.vars and the
@ -329,27 +305,15 @@ func (lv *Liveness) valueEffects(v *ssa.Value) (int32, liveEffect) {
} }
var effect liveEffect var effect liveEffect
if n.Addrtaken() { // Read is a read, obviously.
if v.Op != ssa.OpVarKill { //
effect |= avarinit // Addr is a read also, as any subseqent holder of the pointer must be able
} // to see all the values (including initialization) written so far.
if v.Op == ssa.OpVarDef || v.Op == ssa.OpVarKill { if e&(ssa.SymRead|ssa.SymAddr) != 0 {
effect |= varkill effect |= uevar
} }
} else { if e&ssa.SymWrite != 0 && (!isfat(n.Type) || v.Op == ssa.OpVarDef) {
// Read is a read, obviously. effect |= varkill
// Addr by itself is also implicitly a read.
//
// Addr|Write means that the address is being taken
// but only so that the instruction can write to the value.
// It is not a read.
if e&ssa.SymRead != 0 || e&(ssa.SymAddr|ssa.SymWrite) == ssa.SymAddr {
effect |= uevar
}
if e&ssa.SymWrite != 0 && (!isfat(n.Type) || v.Op == ssa.OpVarDef) {
effect |= varkill
}
} }
if effect == 0 { if effect == 0 {
@ -545,9 +509,6 @@ func newliveness(fn *Node, f *ssa.Func, vars []*Node, idx map[*Node]int32, stkpt
be.varkill = varRegVec{vars: bulk.next()} be.varkill = varRegVec{vars: bulk.next()}
be.livein = varRegVec{vars: bulk.next()} be.livein = varRegVec{vars: bulk.next()}
be.liveout = varRegVec{vars: bulk.next()} be.liveout = varRegVec{vars: bulk.next()}
be.avarinit = bulk.next()
be.avarinitany = bulk.next()
be.avarinitall = bulk.next()
} }
lv.livenessMap.reset(lv.f.NumValues()) lv.livenessMap.reset(lv.f.NumValues())
@ -869,19 +830,6 @@ func (lv *Liveness) prologue() {
} }
be.uevar.regs |= regUevar be.uevar.regs |= regUevar
} }
// Walk the block instructions forward to update avarinit bits.
// avarinit describes the effect at the end of the block, not the beginning.
for _, val := range b.Values {
pos, e := lv.valueEffects(val)
// No need for regEffects because registers never appear in avarinit.
if e&varkill != 0 {
be.avarinit.Unset(pos)
}
if e&avarinit != 0 {
be.avarinit.Set(pos)
}
}
} }
} }
@ -892,51 +840,10 @@ func (lv *Liveness) solve() {
nvars := int32(len(lv.vars)) nvars := int32(len(lv.vars))
newlivein := varRegVec{vars: bvalloc(nvars)} newlivein := varRegVec{vars: bvalloc(nvars)}
newliveout := varRegVec{vars: bvalloc(nvars)} newliveout := varRegVec{vars: bvalloc(nvars)}
any := bvalloc(nvars)
all := bvalloc(nvars)
// Push avarinitall, avarinitany forward. // Walk blocks in postorder ordering. This improves convergence.
// avarinitall says the addressed var is initialized along all paths reaching the block exit.
// avarinitany says the addressed var is initialized along some path reaching the block exit.
for _, b := range lv.f.Blocks {
be := lv.blockEffects(b)
if b == lv.f.Entry {
be.avarinitall.Copy(be.avarinit)
} else {
be.avarinitall.Clear()
be.avarinitall.Not()
}
be.avarinitany.Copy(be.avarinit)
}
// Walk blocks in the general direction of propagation (RPO
// for avarinit{any,all}, and PO for live{in,out}). This
// improves convergence.
po := lv.f.Postorder() po := lv.f.Postorder()
for change := true; change; {
change = false
for i := len(po) - 1; i >= 0; i-- {
b := po[i]
be := lv.blockEffects(b)
lv.avarinitanyall(b, any, all)
any.AndNot(any, be.varkill.vars)
all.AndNot(all, be.varkill.vars)
any.Or(any, be.avarinit)
all.Or(all, be.avarinit)
if !any.Eq(be.avarinitany) {
change = true
be.avarinitany.Copy(any)
}
if !all.Eq(be.avarinitall) {
change = true
be.avarinitall.Copy(all)
}
}
}
// Iterate through the blocks in reverse round-robin fashion. A work // Iterate through the blocks in reverse round-robin fashion. A work
// queue might be slightly faster. As is, the number of iterations is // queue might be slightly faster. As is, the number of iterations is
// so low that it hardly seems to be worth the complexity. // so low that it hardly seems to be worth the complexity.
@ -957,7 +864,7 @@ func (lv *Liveness) solve() {
newliveout.vars.Set(pos) newliveout.vars.Set(pos)
} }
case ssa.BlockExit: case ssa.BlockExit:
// nothing to do // panic exit - nothing to do
default: default:
// A variable is live on output from this block // A variable is live on output from this block
// if it is live on input to some successor. // if it is live on input to some successor.
@ -975,7 +882,7 @@ func (lv *Liveness) solve() {
} }
// A variable is live on input to this block // A variable is live on input to this block
// if it is live on output from this block and // if it is used by this block, or live on output from this block and
// not set by the code in this block. // not set by the code in this block.
// //
// in[b] = uevar[b] \cup (out[b] \setminus varkill[b]) // in[b] = uevar[b] \cup (out[b] \setminus varkill[b])
@ -990,8 +897,6 @@ func (lv *Liveness) solve() {
func (lv *Liveness) epilogue() { func (lv *Liveness) epilogue() {
nvars := int32(len(lv.vars)) nvars := int32(len(lv.vars))
liveout := varRegVec{vars: bvalloc(nvars)} liveout := varRegVec{vars: bvalloc(nvars)}
any := bvalloc(nvars)
all := bvalloc(nvars)
livedefer := bvalloc(nvars) // always-live variables livedefer := bvalloc(nvars) // always-live variables
// If there is a defer (that could recover), then all output // If there is a defer (that could recover), then all output
@ -1017,6 +922,9 @@ func (lv *Liveness) epilogue() {
livedefer.Set(int32(i)) livedefer.Set(int32(i))
} }
if n.IsOutputParamHeapAddr() { if n.IsOutputParamHeapAddr() {
// This variable will be overwritten early in the function
// prologue (from the result of a mallocgc) but we need to
// zero it in case that malloc causes a stack scan.
n.Name.SetNeedzero(true) n.Name.SetNeedzero(true)
livedefer.Set(int32(i)) livedefer.Set(int32(i))
} }
@ -1033,9 +941,6 @@ func (lv *Liveness) epilogue() {
{ {
// Reserve an entry for function entry. // Reserve an entry for function entry.
live := bvalloc(nvars) live := bvalloc(nvars)
for _, pos := range lv.cache.textavarinit {
live.Set(pos)
}
lv.livevars = append(lv.livevars, varRegVec{vars: live}) lv.livevars = append(lv.livevars, varRegVec{vars: live})
} }
@ -1043,53 +948,14 @@ func (lv *Liveness) epilogue() {
be := lv.blockEffects(b) be := lv.blockEffects(b)
firstBitmapIndex := len(lv.livevars) firstBitmapIndex := len(lv.livevars)
// Compute avarinitany and avarinitall for entry to block.
// This duplicates information known during Liveness.solve
// but avoids storing two more vectors for each block.
lv.avarinitanyall(b, any, all)
// Walk forward through the basic block instructions and // Walk forward through the basic block instructions and
// allocate liveness maps for those instructions that need them. // allocate liveness maps for those instructions that need them.
// Seed the maps with information about the addrtaken variables.
for _, v := range b.Values { for _, v := range b.Values {
pos, e := lv.valueEffects(v)
// No need for regEffects because registers never appear in avarinit.
if e&varkill != 0 {
any.Unset(pos)
all.Unset(pos)
}
if e&avarinit != 0 {
any.Set(pos)
all.Set(pos)
}
if !lv.issafepoint(v) { if !lv.issafepoint(v) {
continue continue
} }
// Annotate ambiguously live variables so that they can
// be zeroed at function entry and at VARKILL points.
// liveout is dead here and used as a temporary.
liveout.vars.AndNot(any, all)
if !liveout.vars.IsEmpty() {
for pos := int32(0); pos < liveout.vars.n; pos++ {
if !liveout.vars.Get(pos) {
continue
}
all.Set(pos) // silence future warnings in this block
n := lv.vars[pos]
if !n.Name.Needzero() {
n.Name.SetNeedzero(true)
if debuglive >= 1 {
Warnl(v.Pos, "%v: %L is ambiguously live", lv.fn.Func.Nname, n)
}
}
}
}
// Live stuff first.
live := bvalloc(nvars) live := bvalloc(nvars)
live.Copy(any)
lv.livevars = append(lv.livevars, varRegVec{vars: live}) lv.livevars = append(lv.livevars, varRegVec{vars: live})
} }
@ -1128,6 +994,17 @@ func (lv *Liveness) epilogue() {
Fatalf("bad index for entry point: %v", index) Fatalf("bad index for entry point: %v", index)
} }
// Check to make sure only input variables are live.
for i, n := range lv.vars {
if !liveout.vars.Get(int32(i)) {
continue
}
if n.Class() == PPARAM {
continue // ok
}
Fatalf("bad live variable at entry of %v: %L", lv.fn.Func.Nname, n)
}
// Record live variables. // Record live variables.
live := &lv.livevars[index] live := &lv.livevars[index]
live.Or(*live, liveout) live.Or(*live, liveout)
@ -1330,28 +1207,6 @@ func clobberPtr(b *ssa.Block, v *Node, offset int64) {
b.NewValue0IA(src.NoXPos, ssa.OpClobber, types.TypeVoid, offset, v) b.NewValue0IA(src.NoXPos, ssa.OpClobber, types.TypeVoid, offset, v)
} }
func (lv *Liveness) avarinitanyall(b *ssa.Block, any, all bvec) {
if len(b.Preds) == 0 {
any.Clear()
all.Clear()
for _, pos := range lv.cache.textavarinit {
any.Set(pos)
all.Set(pos)
}
return
}
be := lv.blockEffects(b.Preds[0].Block())
any.Copy(be.avarinitany)
all.Copy(be.avarinitall)
for _, pred := range b.Preds[1:] {
be := lv.blockEffects(pred.Block())
any.Or(any, be.avarinitany)
all.And(all, be.avarinitall)
}
}
// Compact coalesces identical bitmaps from lv.livevars into the sets // Compact coalesces identical bitmaps from lv.livevars into the sets
// lv.stackMapSet and lv.regMaps. // lv.stackMapSet and lv.regMaps.
// //
@ -1559,7 +1414,6 @@ func (lv *Liveness) printDebug() {
printed = false printed = false
printed = lv.printeffect(printed, "uevar", pos, effect&uevar != 0, regUevar) printed = lv.printeffect(printed, "uevar", pos, effect&uevar != 0, regUevar)
printed = lv.printeffect(printed, "varkill", pos, effect&varkill != 0, regKill) printed = lv.printeffect(printed, "varkill", pos, effect&varkill != 0, regKill)
printed = lv.printeffect(printed, "avarinit", pos, effect&avarinit != 0, 0)
if printed { if printed {
fmt.Printf("\n") fmt.Printf("\n")
} }
@ -1596,9 +1450,6 @@ func (lv *Liveness) printDebug() {
printed = false printed = false
printed = lv.printbvec(printed, "varkill", be.varkill) printed = lv.printbvec(printed, "varkill", be.varkill)
printed = lv.printbvec(printed, "liveout", be.liveout) printed = lv.printbvec(printed, "liveout", be.liveout)
printed = lv.printbvec(printed, "avarinit", varRegVec{vars: be.avarinit})
printed = lv.printbvec(printed, "avarinitany", varRegVec{vars: be.avarinitany})
printed = lv.printbvec(printed, "avarinitall", varRegVec{vars: be.avarinitall})
if printed { if printed {
fmt.Printf("\n") fmt.Printf("\n")
} }

6
src/cmd/compile/internal/gc/sinit.go
View File

@ -839,6 +839,10 @@ func slicelit(ctxt initContext, n *Node, var_ *Node, init *Nodes) {
a = nod(OAS, x, nil) a = nod(OAS, x, nil)
a = typecheck(a, Etop) a = typecheck(a, Etop)
init.Append(a) // zero new temp init.Append(a) // zero new temp
} else {
// Declare that we're about to initialize all of x.
// (Which happens at the *vauto = vstat below.)
init.Append(nod(OVARDEF, x, nil))
} }
a = nod(OADDR, x, nil) a = nod(OADDR, x, nil)
@ -849,6 +853,8 @@ func slicelit(ctxt initContext, n *Node, var_ *Node, init *Nodes) {
a = typecheck(a, Etop) a = typecheck(a, Etop)
init.Append(a) // zero new temp init.Append(a) // zero new temp
a = a.Left a = a.Left
} else {
init.Append(nod(OVARDEF, a, nil))
} }
a = nod(OADDR, a, nil) a = nod(OADDR, a, nil)

32
src/cmd/compile/internal/gc/ssa.go
View File

@ -755,8 +755,8 @@ func (s *state) stmtList(l Nodes) {
// stmt converts the statement n to SSA and adds it to s. // stmt converts the statement n to SSA and adds it to s.
func (s *state) stmt(n *Node) { func (s *state) stmt(n *Node) {
if !(n.Op == OVARKILL || n.Op == OVARLIVE) { if !(n.Op == OVARKILL || n.Op == OVARLIVE || n.Op == OVARDEF) {
// OVARKILL and OVARLIVE are invisible to the programmer, so we don't use their line numbers to avoid confusion in debugging. // OVARKILL, OVARLIVE, and OVARDEF are invisible to the programmer, so we don't use their line numbers to avoid confusion in debugging.
s.pushLine(n.Pos) s.pushLine(n.Pos)
defer s.popLine() defer s.popLine()
} }
@ -1170,6 +1170,10 @@ func (s *state) stmt(n *Node) {
} }
s.startBlock(bEnd) s.startBlock(bEnd)
case OVARDEF:
if !s.canSSA(n.Left) {
s.vars[&memVar] = s.newValue1Apos(ssa.OpVarDef, types.TypeMem, n.Left, s.mem(), false)
}
case OVARKILL: case OVARKILL:
// Insert a varkill op to record that a variable is no longer live. // Insert a varkill op to record that a variable is no longer live.
// We only care about liveness info at call sites, so putting the // We only care about liveness info at call sites, so putting the
@ -4977,6 +4981,12 @@ func emitStackObjects(e *ssafn, pp *Progs) {
p.To.Type = obj.TYPE_MEM p.To.Type = obj.TYPE_MEM
p.To.Name = obj.NAME_EXTERN p.To.Name = obj.NAME_EXTERN
p.To.Sym = x p.To.Sym = x
if debuglive != 0 {
for _, v := range vars {
Warnl(v.Pos, "stack object %v %s", v, v.Type.String())
}
}
} }
// genssa appends entries to pp for each instruction in f. // genssa appends entries to pp for each instruction in f.
@ -5056,24 +5066,8 @@ func genssa(f *ssa.Func, pp *Progs) {
case ssa.OpGetG: case ssa.OpGetG:
// nothing to do when there's a g register, // nothing to do when there's a g register,
// and checkLower complains if there's not // and checkLower complains if there's not
case ssa.OpVarDef, ssa.OpVarLive, ssa.OpKeepAlive: case ssa.OpVarDef, ssa.OpVarLive, ssa.OpKeepAlive, ssa.OpVarKill:
// nothing to do; already used by liveness // nothing to do; already used by liveness
case ssa.OpVarKill:
// Zero variable if it is ambiguously live.
// After the VARKILL anything this variable references
// might be collected. If it were to become live again later,
// the GC will see references to already-collected objects.
// See issue 20029.
n := v.Aux.(*Node)
if n.Name.Needzero() {
if n.Class() != PAUTO {
v.Fatalf("zero of variable which isn't PAUTO %v", n)
}
if n.Type.Size()%int64(Widthptr) != 0 {
v.Fatalf("zero of variable not a multiple of ptr size %v", n)
}
thearch.ZeroAuto(s.pp, n)
}
case ssa.OpPhi: case ssa.OpPhi:
CheckLoweredPhi(v) CheckLoweredPhi(v)
case ssa.OpConvert: case ssa.OpConvert:

1
src/cmd/compile/internal/gc/syntax.go
View File

@ -739,6 +739,7 @@ const (
OCLOSUREVAR // variable reference at beginning of closure function OCLOSUREVAR // variable reference at beginning of closure function
OCFUNC // reference to c function pointer (not go func value) OCFUNC // reference to c function pointer (not go func value)
OCHECKNIL // emit code to ensure pointer/interface not nil OCHECKNIL // emit code to ensure pointer/interface not nil
OVARDEF // variable is about to be fully initialized
OVARKILL // variable is dead OVARKILL // variable is dead
OVARLIVE // variable is alive OVARLIVE // variable is alive
OINDREGSP // offset plus indirect of REGSP, such as 8(SP). OINDREGSP // offset plus indirect of REGSP, such as 8(SP).

5
src/cmd/compile/internal/ssa/gen/genericOps.go
View File

@ -470,8 +470,9 @@ var genericOps = []opData{
{name: "VarDef", argLength: 1, aux: "Sym", typ: "Mem", symEffect: "None", zeroWidth: true}, // aux is a *gc.Node of a variable that is about to be initialized. arg0=mem, returns mem {name: "VarDef", argLength: 1, aux: "Sym", typ: "Mem", symEffect: "None", zeroWidth: true}, // aux is a *gc.Node of a variable that is about to be initialized. arg0=mem, returns mem
{name: "VarKill", argLength: 1, aux: "Sym", symEffect: "None"}, // aux is a *gc.Node of a variable that is known to be dead. arg0=mem, returns mem {name: "VarKill", argLength: 1, aux: "Sym", symEffect: "None"}, // aux is a *gc.Node of a variable that is known to be dead. arg0=mem, returns mem
{name: "VarLive", argLength: 1, aux: "Sym", symEffect: "Read", zeroWidth: true}, // aux is a *gc.Node of a variable that must be kept live. arg0=mem, returns mem // TODO: what's the difference betweeen VarLive and KeepAlive?
{name: "KeepAlive", argLength: 2, typ: "Mem", zeroWidth: true}, // arg[0] is a value that must be kept alive until this mark. arg[1]=mem, returns mem {name: "VarLive", argLength: 1, aux: "Sym", symEffect: "Read", zeroWidth: true}, // aux is a *gc.Node of a variable that must be kept live. arg0=mem, returns mem
{name: "KeepAlive", argLength: 2, typ: "Mem", zeroWidth: true}, // arg[0] is a value that must be kept alive until this mark. arg[1]=mem, returns mem
// Ops for breaking 64-bit operations on 32-bit architectures // Ops for breaking 64-bit operations on 32-bit architectures
{name: "Int64Make", argLength: 2, typ: "UInt64"}, // arg0=hi, arg1=lo {name: "Int64Make", argLength: 2, typ: "UInt64"}, // arg0=hi, arg1=lo

5
src/runtime/chan.go
View File

@ -232,6 +232,11 @@ func chansend(c *hchan, ep unsafe.Pointer, block bool, callerpc uintptr) bool {
gp.param = nil gp.param = nil
c.sendq.enqueue(mysg) c.sendq.enqueue(mysg)
goparkunlock(&c.lock, waitReasonChanSend, traceEvGoBlockSend, 3) goparkunlock(&c.lock, waitReasonChanSend, traceEvGoBlockSend, 3)
// Ensure the value being sent is kept alive until the
// receiver copies it out. The sudog has a pointer to the
// stack object, but sudogs aren't considered as roots of the
// stack tracer.
KeepAlive(ep)
// someone woke us up. // someone woke us up.
if mysg != gp.waiting { if mysg != gp.waiting {

48
src/runtime/gcinfo_test.go
View File

@ -35,14 +35,46 @@ func TestGCInfo(t *testing.T) {
verifyGCInfo(t, "data eface", &dataEface, infoEface) verifyGCInfo(t, "data eface", &dataEface, infoEface)
verifyGCInfo(t, "data iface", &dataIface, infoIface) verifyGCInfo(t, "data iface", &dataIface, infoIface)
verifyGCInfo(t, "stack Ptr", new(Ptr), infoPtr) {
verifyGCInfo(t, "stack ScalarPtr", new(ScalarPtr), infoScalarPtr) var x Ptr
verifyGCInfo(t, "stack PtrScalar", new(PtrScalar), infoPtrScalar) verifyGCInfo(t, "stack Ptr", &x, infoPtr)
verifyGCInfo(t, "stack BigStruct", new(BigStruct), infoBigStruct()) runtime.KeepAlive(x)
verifyGCInfo(t, "stack string", new(string), infoString) }
verifyGCInfo(t, "stack slice", new([]string), infoSlice) {
verifyGCInfo(t, "stack eface", new(interface{}), infoEface) var x ScalarPtr
verifyGCInfo(t, "stack iface", new(Iface), infoIface) verifyGCInfo(t, "stack ScalarPtr", &x, infoScalarPtr)
runtime.KeepAlive(x)
}
{
var x PtrScalar
verifyGCInfo(t, "stack PtrScalar", &x, infoPtrScalar)
runtime.KeepAlive(x)
}
{
var x BigStruct
verifyGCInfo(t, "stack BigStruct", &x, infoBigStruct())
runtime.KeepAlive(x)
}
{
var x string
verifyGCInfo(t, "stack string", &x, infoString)
runtime.KeepAlive(x)
}
{
var x []string
verifyGCInfo(t, "stack slice", &x, infoSlice)
runtime.KeepAlive(x)
}
{
var x interface{}
verifyGCInfo(t, "stack eface", &x, infoEface)
runtime.KeepAlive(x)
}
{
var x Iface
verifyGCInfo(t, "stack iface", &x, infoIface)
runtime.KeepAlive(x)
}
for i := 0; i < 10; i++ { for i := 0; i < 10; i++ {
verifyGCInfo(t, "heap Ptr", escape(new(Ptr)), trimDead(padDead(infoPtr))) verifyGCInfo(t, "heap Ptr", escape(new(Ptr)), trimDead(padDead(infoPtr)))

9
src/runtime/mbitmap.go
View File

@ -1994,7 +1994,9 @@ func reflect_gcbits(x interface{}) []byte {
return ret return ret
} }
// Returns GC type info for object p for testing. // Returns GC type info for the pointer stored in ep for testing.
// If ep points to the stack, only static live information will be returned
// (i.e. not for objects which are only dynamically live stack objects).
func getgcmask(ep interface{}) (mask []byte) { func getgcmask(ep interface{}) (mask []byte) {
e := *efaceOf(&ep) e := *efaceOf(&ep)
p := e.data p := e.data
@ -2051,11 +2053,6 @@ func getgcmask(ep interface{}) (mask []byte) {
_g_ := getg() _g_ := getg()
gentraceback(_g_.m.curg.sched.pc, _g_.m.curg.sched.sp, 0, _g_.m.curg, 0, nil, 1000, getgcmaskcb, noescape(unsafe.Pointer(&frame)), 0) gentraceback(_g_.m.curg.sched.pc, _g_.m.curg.sched.sp, 0, _g_.m.curg, 0, nil, 1000, getgcmaskcb, noescape(unsafe.Pointer(&frame)), 0)
if frame.fn.valid() { if frame.fn.valid() {
// TODO: once stack objects are enabled (and their pointers
// are no longer described by the stack pointermap directly),
// tests using this will probably need fixing. We might need
// to loop through the stackobjects and if we're inside one,
// use the pointermap from that object.
locals, _, _ := getStackMap(&frame, nil, false) locals, _, _ := getStackMap(&frame, nil, false)
if locals.n == 0 { if locals.n == 0 {
return return

8
test/fixedbugs/issue20250.go
View File

@ -15,10 +15,10 @@ type T struct {
} }
func f(a T) { // ERROR "live at entry to f: a" func f(a T) { // ERROR "live at entry to f: a"
var e interface{} var e interface{} // ERROR "stack object e interface \{\}$"
func() { // ERROR "live at entry to f.func1: a &e" func() { // ERROR "live at entry to f.func1: a &e"
e = a.s // ERROR "live at call to convT2Estring: a &e" e = a.s // ERROR "live at call to convT2Estring: &e" "stack object a T$"
}() // ERROR "live at call to f.func1: e$" }()
// Before the fix, both a and e were live at the previous line. // Before the fix, both a and e were live at the previous line.
_ = e _ = e
} }

175
test/live.go
View File

@ -32,9 +32,9 @@ func printbytepointer(*byte)
func printint(int) func printint(int)
func f1() { func f1() {
var x *int var x *int // ERROR "stack object x \*int$"
printpointer(&x) // ERROR "live at call to printpointer: x$"
printpointer(&x) // ERROR "live at call to printpointer: x$" printpointer(&x) // ERROR "live at call to printpointer: x$"
printpointer(&x)
} }
func f2(b bool) { func f2(b bool) {
@ -42,9 +42,9 @@ func f2(b bool) {
printint(0) // nothing live here printint(0) // nothing live here
return return
} }
var x *int var x *int // ERROR "stack object x \*int$"
printpointer(&x) // ERROR "live at call to printpointer: x$"
printpointer(&x) // ERROR "live at call to printpointer: x$" printpointer(&x) // ERROR "live at call to printpointer: x$"
printpointer(&x)
} }
func f3(b1, b2 bool) { func f3(b1, b2 bool) {
@ -60,15 +60,15 @@ func f3(b1, b2 bool) {
} }
if b2 { if b2 {
var x *int var x *int // ERROR "stack object x \*int$"
printpointer(&x) // ERROR "live at call to printpointer: x$"
printpointer(&x) // ERROR "live at call to printpointer: x$" printpointer(&x) // ERROR "live at call to printpointer: x$"
printpointer(&x)
} else { } else {
var y *int var y *int // ERROR "stack object y \*int$"
printpointer(&y) // ERROR "live at call to printpointer: y$"
printpointer(&y) // ERROR "live at call to printpointer: y$" printpointer(&y) // ERROR "live at call to printpointer: y$"
printpointer(&y)
} }
printint(0) // ERROR "f3: x \(type \*int\) is ambiguously live$" "f3: y \(type \*int\) is ambiguously live$" "live at call to printint: x y$" printint(0) // nothing is live here
} }
// The old algorithm treated x as live on all code that // The old algorithm treated x as live on all code that
@ -83,7 +83,7 @@ func f4(b1, b2 bool) { // x not live here
return return
} }
var z **int var z **int
x := new(int) x := new(int) // ERROR "stack object x \*int$"
*x = 42 *x = 42
z = &x z = &x
printint(**z) // ERROR "live at call to printint: x$" printint(**z) // ERROR "live at call to printint: x$"
@ -99,15 +99,15 @@ func f4(b1, b2 bool) { // x not live here
func f5(b1 bool) { func f5(b1 bool) {
var z **int var z **int
if b1 { if b1 {
x := new(int) x := new(int) // ERROR "stack object x \*int$"
*x = 42 *x = 42
z = &x z = &x
} else { } else {
y := new(int) y := new(int) // ERROR "stack object y \*int$"
*y = 54 *y = 54
z = &y z = &y
} }
printint(**z) // ERROR "f5: x \(type \*int\) is ambiguously live$" "f5: y \(type \*int\) is ambiguously live$" "live at call to printint: x y$" printint(**z) // nothing live here
} }
// confusion about the _ result used to cause spurious "live at entry to f6: _". // confusion about the _ result used to cause spurious "live at entry to f6: _".
@ -119,7 +119,7 @@ func f6() (_, y string) {
// confusion about addressed results used to cause "live at entry to f7: x". // confusion about addressed results used to cause "live at entry to f7: x".
func f7() (x string) { func f7() (x string) { // ERROR "stack object x string"
_ = &x _ = &x
x = "hello" x = "hello"
return return
@ -141,7 +141,7 @@ var i9 interface{}
func f9() bool { func f9() bool {
g8() g8()
x := i9 x := i9
y := interface{}(str()) // ERROR "live at call to convT2Estring: .autotmp_[0-9]+ x.data$" "live at call to str: x.data$" y := interface{}(str()) // ERROR "live at call to convT2Estring: x.data$" "live at call to str: x.data$" "stack object .autotmp_[0-9]+ string$"
i9 = y // make y escape so the line above has to call convT2E i9 = y // make y escape so the line above has to call convT2E
return x != y return x != y
} }
@ -163,7 +163,7 @@ var b bool
// this used to have a spurious "live at entry to f11a: ~r0" // this used to have a spurious "live at entry to f11a: ~r0"
func f11a() *int { func f11a() *int {
select { // ERROR "live at call to selectgo: .autotmp_[0-9]+$" select { // ERROR "stack object .autotmp_[0-9]+ \[2\]struct"
case <-c: case <-c:
return nil return nil
case <-c: case <-c:
@ -178,7 +178,7 @@ func f11b() *int {
// get to the bottom of the function. // get to the bottom of the function.
// This used to have a spurious "live at call to printint: p". // This used to have a spurious "live at call to printint: p".
printint(1) // nothing live here! printint(1) // nothing live here!
select { // ERROR "live at call to selectgo: .autotmp_[0-9]+$" select { // ERROR "stack object .autotmp_[0-9]+ \[2\]struct"
case <-c: case <-c:
return nil return nil
case <-c: case <-c:
@ -198,7 +198,7 @@ func f11c() *int {
// Unlike previous, the cases in this select fall through, // Unlike previous, the cases in this select fall through,
// so we can get to the println, so p is not dead. // so we can get to the println, so p is not dead.
printint(1) // ERROR "live at call to printint: p$" printint(1) // ERROR "live at call to printint: p$"
select { // ERROR "live at call to selectgo: .autotmp_[0-9]+ p$" select { // ERROR "live at call to selectgo: p$" "stack object .autotmp_[0-9]+ \[2\]struct"
case <-c: case <-c:
case <-c: case <-c:
} }
@ -233,8 +233,8 @@ func h13(string, string) string
// more incorrectly placed VARDEF. // more incorrectly placed VARDEF.
func f14() { func f14() {
x := g14() x := g14() // ERROR "stack object x string$"
printstringpointer(&x) // ERROR "live at call to printstringpointer: x$" printstringpointer(&x)
} }
func g14() string func g14() string
@ -254,10 +254,10 @@ func iface() interface{}
func f16() { func f16() {
if b { if b {
delete(mi, iface()) // ERROR "live at call to mapdelete: .autotmp_[0-9]+$" delete(mi, iface()) // ERROR "stack object .autotmp_[0-9]+ interface \{\}$"
} }
delete(mi, iface()) // ERROR "live at call to mapdelete: .autotmp_[0-9]+$" delete(mi, iface()) // ERROR "stack object .autotmp_[0-9]+ interface \{\}$"
delete(mi, iface()) // ERROR "live at call to mapdelete: .autotmp_[0-9]+$" delete(mi, iface()) // ERROR "stack object .autotmp_[0-9]+ interface \{\}$"
} }
var m2s map[string]*byte var m2s map[string]*byte
@ -300,10 +300,10 @@ func f18() {
// temporary introduced by orderexpr. // temporary introduced by orderexpr.
var z *byte var z *byte
if b { if b {
z = m2[g18()] // ERROR "live at call to mapaccess1: .autotmp_[0-9]+$" z = m2[g18()] // ERROR "stack object .autotmp_[0-9]+ \[2\]string$"
} }
z = m2[g18()] // ERROR "live at call to mapaccess1: .autotmp_[0-9]+$" z = m2[g18()] // ERROR "stack object .autotmp_[0-9]+ \[2\]string$"
z = m2[g18()] // ERROR "live at call to mapaccess1: .autotmp_[0-9]+$" z = m2[g18()] // ERROR "stack object .autotmp_[0-9]+ \[2\]string$"
printbytepointer(z) printbytepointer(z)
} }
@ -317,30 +317,30 @@ func f19() {
var z *byte var z *byte
if b { if b {
z = <-ch // ERROR "live at call to chanrecv1: .autotmp_[0-9]+$" z = <-ch // ERROR "stack object .autotmp_[0-9]+ \*byte$"
} }
z = <-ch // ERROR "live at call to chanrecv1: .autotmp_[0-9]+$" z = <-ch // ERROR "stack object .autotmp_[0-9]+ \*byte$"
z = <-ch // ERROR "live at call to chanrecv1: .autotmp_[0-9]+$" z = <-ch // ERROR "stack object .autotmp_[0-9]+ \*byte$" "live at call to chanrecv1: .autotmp_[0-9]+$"
printbytepointer(z) printbytepointer(z)
} }
func f20() { func f20() {
// src temporary for channel send // src temporary for channel send
if b { if b {
ch <- byteptr() // ERROR "live at call to chansend1: .autotmp_[0-9]+$" ch <- byteptr() // ERROR "stack object .autotmp_[0-9]+ \*byte$"
} }
ch <- byteptr() // ERROR "live at call to chansend1: .autotmp_[0-9]+$" ch <- byteptr() // ERROR "stack object .autotmp_[0-9]+ \*byte$"
ch <- byteptr() // ERROR "live at call to chansend1: .autotmp_[0-9]+$" ch <- byteptr() // ERROR "stack object .autotmp_[0-9]+ \*byte$"
} }
func f21() { func f21() {
// key temporary for mapaccess using array literal key. // key temporary for mapaccess using array literal key.
var z *byte var z *byte
if b { if b {
z = m2[[2]string{"x", "y"}] // ERROR "live at call to mapaccess1: .autotmp_[0-9]+$" z = m2[[2]string{"x", "y"}] // ERROR "stack object .autotmp_[0-9]+ \[2\]string$"
} }
z = m2[[2]string{"x", "y"}] // ERROR "live at call to mapaccess1: .autotmp_[0-9]+$" z = m2[[2]string{"x", "y"}] // ERROR "stack object .autotmp_[0-9]+ \[2\]string$"
z = m2[[2]string{"x", "y"}] // ERROR "live at call to mapaccess1: .autotmp_[0-9]+$" z = m2[[2]string{"x", "y"}] // ERROR "stack object .autotmp_[0-9]+ \[2\]string$"
printbytepointer(z) printbytepointer(z)
} }
@ -349,10 +349,10 @@ func f23() {
var z *byte var z *byte
var ok bool var ok bool
if b { if b {
z, ok = m2[[2]string{"x", "y"}] // ERROR "live at call to mapaccess2: .autotmp_[0-9]+$" z, ok = m2[[2]string{"x", "y"}] // ERROR "stack object .autotmp_[0-9]+ \[2\]string$"
} }
z, ok = m2[[2]string{"x", "y"}] // ERROR "live at call to mapaccess2: .autotmp_[0-9]+$" z, ok = m2[[2]string{"x", "y"}] // ERROR "stack object .autotmp_[0-9]+ \[2\]string$"
z, ok = m2[[2]string{"x", "y"}] // ERROR "live at call to mapaccess2: .autotmp_[0-9]+$" z, ok = m2[[2]string{"x", "y"}] // ERROR "stack object .autotmp_[0-9]+ \[2\]string$"
printbytepointer(z) printbytepointer(z)
print(ok) print(ok)
} }
@ -361,10 +361,10 @@ func f24() {
// key temporary for map access using array literal key. // key temporary for map access using array literal key.
// value temporary too. // value temporary too.
if b { if b {
m2[[2]string{"x", "y"}] = nil // ERROR "live at call to mapassign: .autotmp_[0-9]+$" m2[[2]string{"x", "y"}] = nil // ERROR "stack object .autotmp_[0-9]+ \[2\]string$"
} }
m2[[2]string{"x", "y"}] = nil // ERROR "live at call to mapassign: .autotmp_[0-9]+$" m2[[2]string{"x", "y"}] = nil // ERROR "stack object .autotmp_[0-9]+ \[2\]string$"
m2[[2]string{"x", "y"}] = nil // ERROR "live at call to mapassign: .autotmp_[0-9]+$" m2[[2]string{"x", "y"}] = nil // ERROR "stack object .autotmp_[0-9]+ \[2\]string$"
} }
// defer should not cause spurious ambiguously live variables // defer should not cause spurious ambiguously live variables
@ -387,10 +387,10 @@ func g25()
func f26(b bool) { func f26(b bool) {
if b { if b {
print26((*int)(nil), (*int)(nil), (*int)(nil)) // ERROR "live at call to print26: .autotmp_[0-9]+$" print26((*int)(nil), (*int)(nil), (*int)(nil)) // ERROR "stack object .autotmp_[0-9]+ \[3\]interface \{\}$"
} }
print26((*int)(nil), (*int)(nil), (*int)(nil)) // ERROR "live at call to print26: .autotmp_[0-9]+$" print26((*int)(nil), (*int)(nil), (*int)(nil)) // ERROR "stack object .autotmp_[0-9]+ \[3\]interface \{\}$"
print26((*int)(nil), (*int)(nil), (*int)(nil)) // ERROR "live at call to print26: .autotmp_[0-9]+$" print26((*int)(nil), (*int)(nil), (*int)(nil)) // ERROR "stack object .autotmp_[0-9]+ \[3\]interface \{\}$"
printnl() printnl()
} }
@ -402,10 +402,10 @@ func print26(...interface{})
func f27(b bool) { func f27(b bool) {
x := 0 x := 0
if b { if b {
call27(func() { x++ }) // ERROR "live at call to call27: .autotmp_[0-9]+$" call27(func() { x++ }) // ERROR "stack object .autotmp_[0-9]+ struct \{"
} }
call27(func() { x++ }) // ERROR "live at call to call27: .autotmp_[0-9]+$" call27(func() { x++ }) // ERROR "stack object .autotmp_[0-9]+ struct \{"
call27(func() { x++ }) // ERROR "live at call to call27: .autotmp_[0-9]+$" call27(func() { x++ }) // ERROR "stack object .autotmp_[0-9]+ struct \{"
printnl() printnl()
} }
@ -414,11 +414,11 @@ func f27(b bool) {
func f27defer(b bool) { func f27defer(b bool) {
x := 0 x := 0
if b { if b {
defer call27(func() { x++ }) // ERROR "live at call to deferproc: .autotmp_[0-9]+$" "live at call to deferreturn: .autotmp_[0-9]+$" defer call27(func() { x++ }) // ERROR "stack object .autotmp_[0-9]+ struct \{"
} }
defer call27(func() { x++ }) // ERROR "f27defer: .autotmp_[0-9]+ \(type struct { F uintptr; x \*int }\) is ambiguously live$" "live at call to deferproc: .autotmp_[0-9]+ .autotmp_[0-9]+$" "live at call to deferreturn: .autotmp_[0-9]+ .autotmp_[0-9]+$" defer call27(func() { x++ }) // ERROR "stack object .autotmp_[0-9]+ struct \{"
printnl() // ERROR "live at call to printnl: .autotmp_[0-9]+ .autotmp_[0-9]+$" printnl()
} // ERROR "live at call to deferreturn: .autotmp_[0-9]+ .autotmp_[0-9]+$" }
// and newproc (go) escapes to the heap // and newproc (go) escapes to the heap
@ -440,24 +440,24 @@ var s1, s2, s3, s4, s5, s6, s7, s8, s9, s10 string
func f28(b bool) { func f28(b bool) {
if b { if b {
printstring(s1 + s2 + s3 + s4 + s5 + s6 + s7 + s8 + s9 + s10) // ERROR "live at call to concatstrings: .autotmp_[0-9]+$" "live at call to printstring: .autotmp_[0-9]+$" printstring(s1 + s2 + s3 + s4 + s5 + s6 + s7 + s8 + s9 + s10) // ERROR "stack object .autotmp_[0-9]+ \[10\]string$"
} }
printstring(s1 + s2 + s3 + s4 + s5 + s6 + s7 + s8 + s9 + s10) // ERROR "live at call to concatstrings: .autotmp_[0-9]+$" "live at call to printstring: .autotmp_[0-9]+$" printstring(s1 + s2 + s3 + s4 + s5 + s6 + s7 + s8 + s9 + s10) // ERROR "stack object .autotmp_[0-9]+ \[10\]string$"
printstring(s1 + s2 + s3 + s4 + s5 + s6 + s7 + s8 + s9 + s10) // ERROR "live at call to concatstrings: .autotmp_[0-9]+$" "live at call to printstring: .autotmp_[0-9]+$" printstring(s1 + s2 + s3 + s4 + s5 + s6 + s7 + s8 + s9 + s10) // ERROR "stack object .autotmp_[0-9]+ \[10\]string$"
} }
// map iterator should die on end of range loop // map iterator should die on end of range loop
func f29(b bool) { func f29(b bool) {
if b { if b {
for k := range m { // ERROR "live at call to mapiterinit: .autotmp_[0-9]+$" "live at call to mapiternext: .autotmp_[0-9]+$" for k := range m { // ERROR "live at call to mapiterinit: .autotmp_[0-9]+$" "live at call to mapiternext: .autotmp_[0-9]+$" "stack object .autotmp_[0-9]+ map.iter\[string\]int$"
printstring(k) // ERROR "live at call to printstring: .autotmp_[0-9]+$" printstring(k) // ERROR "live at call to printstring: .autotmp_[0-9]+$"
} }
} }
for k := range m { // ERROR "live at call to mapiterinit: .autotmp_[0-9]+$" "live at call to mapiternext: .autotmp_[0-9]+$" for k := range m { // ERROR "live at call to mapiterinit: .autotmp_[0-9]+$" "live at call to mapiternext: .autotmp_[0-9]+$" "stack object .autotmp_[0-9]+ map.iter\[string\]int$"
printstring(k) // ERROR "live at call to printstring: .autotmp_[0-9]+$" printstring(k) // ERROR "live at call to printstring: .autotmp_[0-9]+$"
} }
for k := range m { // ERROR "live at call to mapiterinit: .autotmp_[0-9]+$" "live at call to mapiternext: .autotmp_[0-9]+$" for k := range m { // ERROR "live at call to mapiterinit: .autotmp_[0-9]+$" "live at call to mapiternext: .autotmp_[0-9]+$" "stack object .autotmp_[0-9]+ map.iter\[string\]int$"
printstring(k) // ERROR "live at call to printstring: .autotmp_[0-9]+$" printstring(k) // ERROR "live at call to printstring: .autotmp_[0-9]+$"
} }
} }
@ -473,20 +473,19 @@ type pstruct struct {
} }
func f30(b bool) { func f30(b bool) {
// two live temps during printintpointer(p): // live temp during printintpointer(p):
// in the copy of p.intp and
// the internal iterator pointer if a pointer to pstruct in pstructarr // the internal iterator pointer if a pointer to pstruct in pstructarr
// can not be easily computed by strength reduction. // can not be easily computed by strength reduction.
if b { if b {
for _, p := range pstructarr { for _, p := range pstructarr { // ERROR "stack object .autotmp_[0-9]+ \[10\]pstruct$"
printintpointer(p.intp) // ERROR "live at call to printintpointer: .autotmp_[0-9]+ .autotmp_[0-9]+$" printintpointer(p.intp) // ERROR "live at call to printintpointer: .autotmp_[0-9]+$"
} }
} }
for _, p := range pstructarr { for _, p := range pstructarr { // ERROR "stack object .autotmp_[0-9]+ \[10\]pstruct$"
printintpointer(p.intp) // ERROR "live at call to printintpointer: .autotmp_[0-9]+ .autotmp_[0-9]+$" printintpointer(p.intp) // ERROR "live at call to printintpointer: .autotmp_[0-9]+$"
} }
for _, p := range pstructarr { for _, p := range pstructarr { // ERROR "stack object .autotmp_[0-9]+ \[10\]pstruct$"
printintpointer(p.intp) // ERROR "live at call to printintpointer: .autotmp_[0-9]+ .autotmp_[0-9]+$" printintpointer(p.intp) // ERROR "live at call to printintpointer: .autotmp_[0-9]+$"
} }
} }
@ -494,13 +493,13 @@ func f30(b bool) {
func f31(b1, b2, b3 bool) { func f31(b1, b2, b3 bool) {
if b1 { if b1 {
g31(str()) // ERROR "live at call to convT2Estring: .autotmp_[0-9]+$" "live at call to g31: .autotmp_[0-9]+$" g31(str()) // ERROR "stack object .autotmp_[0-9]+ string$"
} }
if b2 { if b2 {
h31(str()) // ERROR "live at call to convT2Estring: .autotmp_[0-9]+ .autotmp_[0-9]+$" "live at call to h31: .autotmp_[0-9]+$" "live at call to newobject: .autotmp_[0-9]+$" h31(str()) // ERROR "live at call to convT2Estring: .autotmp_[0-9]+$" "live at call to newobject: .autotmp_[0-9]+$" "stack object .autotmp_[0-9]+ string$"
} }
if b3 { if b3 {
panic(str()) // ERROR "live at call to convT2Estring: .autotmp_[0-9]+$" "live at call to gopanic: .autotmp_[0-9]+$" panic(str()) // ERROR "stack object .autotmp_[0-9]+ string$"
} }
print(b3) print(b3)
} }
@ -520,10 +519,10 @@ var t32 T32
func f32(b bool) { func f32(b bool) {
if b { if b {
call32(t32.Inc) // ERROR "live at call to call32: .autotmp_[0-9]+$" call32(t32.Inc) // ERROR "stack object .autotmp_[0-9]+ struct \{"
} }
call32(t32.Inc) // ERROR "live at call to call32: .autotmp_[0-9]+$" call32(t32.Inc) // ERROR "stack object .autotmp_[0-9]+ struct \{"
call32(t32.Inc) // ERROR "live at call to call32: .autotmp_[0-9]+$" call32(t32.Inc) // ERROR "stack object .autotmp_[0-9]+ struct \{"
} }
//go:noescape //go:noescape
@ -535,7 +534,7 @@ func call32(func())
var m33 map[interface{}]int var m33 map[interface{}]int
func f33() { func f33() {
if m33[byteptr()] == 0 { // ERROR "live at call to mapaccess1: .autotmp_[0-9]+$" if m33[byteptr()] == 0 { // ERROR "stack object .autotmp_[0-9]+ interface \{\}$"
printnl() printnl()
return return
} else { } else {
@ -545,7 +544,7 @@ func f33() {
} }
func f34() { func f34() {
if m33[byteptr()] == 0 { // ERROR "live at call to mapaccess1: .autotmp_[0-9]+$" if m33[byteptr()] == 0 { // ERROR "stack object .autotmp_[0-9]+ interface \{\}$"
printnl() printnl()
return return
} }
@ -553,7 +552,8 @@ func f34() {
} }
func f35() { func f35() {
if m33[byteptr()] == 0 && m33[byteptr()] == 0 { // ERROR "live at call to mapaccess1: .autotmp_[0-9]+$" "f35: .autotmp_[0-9]+ \(type interface \{\}\) is ambiguously live$" if m33[byteptr()] == 0 && // ERROR "stack object .autotmp_[0-9]+ interface \{\}"
m33[byteptr()] == 0 { // ERROR "stack object .autotmp_[0-9]+ interface \{\}"
printnl() printnl()
return return
} }
@ -561,7 +561,8 @@ func f35() {
} }
func f36() { func f36() {
if m33[byteptr()] == 0 || m33[byteptr()] == 0 { // ERROR "live at call to mapaccess1: .autotmp_[0-9]+$" "f36: .autotmp_[0-9]+ \(type interface \{\}\) is ambiguously live$" if m33[byteptr()] == 0 || // ERROR "stack object .autotmp_[0-9]+ interface \{\}"
m33[byteptr()] == 0 { // ERROR "stack object .autotmp_[0-9]+ interface \{\}"
printnl() printnl()
return return
} }
@ -569,7 +570,9 @@ func f36() {
} }
func f37() { func f37() {
if (m33[byteptr()] == 0 || m33[byteptr()] == 0) && m33[byteptr()] == 0 { // ERROR "live at call to mapaccess1: .autotmp_[0-9]+$" "f37: .autotmp_[0-9]+ \(type interface \{\}\) is ambiguously live$" if (m33[byteptr()] == 0 || // ERROR "stack object .autotmp_[0-9]+ interface \{\}"
m33[byteptr()] == 0) && // ERROR "stack object .autotmp_[0-9]+ interface \{\}"
m33[byteptr()] == 0 { // ERROR "stack object .autotmp_[0-9]+ interface \{\}"
printnl() printnl()
return return
} }
@ -589,14 +592,14 @@ func f38(b bool) {
// we care that the println lines have no live variables // we care that the println lines have no live variables
// and therefore no output. // and therefore no output.
if b { if b {
select { // ERROR "live at call to selectgo:( .autotmp_[0-9]+)+$" select { // ERROR "live at call to selectgo:( .autotmp_[0-9]+)+$" "stack object .autotmp_[0-9]+ \[4\]struct \{"
case <-fc38(): case <-fc38():
printnl() printnl()
case fc38() <- *fi38(1): // ERROR "live at call to fc38:( .autotmp_[0-9]+)+$" "live at call to fi38:( .autotmp_[0-9]+)+$" case fc38() <- *fi38(1): // ERROR "live at call to fc38:( .autotmp_[0-9]+)+$" "live at call to fi38:( .autotmp_[0-9]+)+$" "stack object .autotmp_[0-9]+ string$"
printnl() printnl()
case *fi38(2) = <-fc38(): // ERROR "live at call to fc38:( .autotmp_[0-9]+)+$" "live at call to fi38:( .autotmp_[0-9]+)+$" case *fi38(2) = <-fc38(): // ERROR "live at call to fc38:( .autotmp_[0-9]+)+$" "live at call to fi38:( .autotmp_[0-9]+)+$" "stack object .autotmp_[0-9]+ string$"
printnl() printnl()
case *fi38(3), *fb38() = <-fc38(): // ERROR "live at call to fb38:( .autotmp_[0-9]+)+$" "live at call to fc38:( .autotmp_[0-9]+)+$" "live at call to fi38:( .autotmp_[0-9]+)+$" case *fi38(3), *fb38() = <-fc38(): // ERROR "stack object .autotmp_[0-9]+ string$" "live at call to fc38:( .autotmp_[0-9]+)+$" "live at call to fi38:( .autotmp_[0-9]+)+$"
printnl() printnl()
} }
printnl() printnl()
@ -655,15 +658,17 @@ func bad40() {
} }
func good40() { func good40() {
ret := T40{} ret := T40{} // ERROR "stack object ret T40$"
ret.m = make(map[int]int) // ERROR "live at call to fastrand: .autotmp_[0-9]+ ret$" ret.m = make(map[int]int) // ERROR "live at call to fastrand: .autotmp_[0-9]+ ret$" "stack object .autotmp_[0-9]+ map.hdr\[int\]int$"
t := &ret t := &ret
printnl() // ERROR "live at call to printnl: .autotmp_[0-9]+ ret$" printnl() // ERROR "live at call to printnl: ret$"
useT40(t) // ERROR "live at call to useT40: .autotmp_[0-9]+ ret$" // Note: ret is live at the printnl because the compiler moves &ret
// from before the printnl to after.
useT40(t)
} }
func ddd1(x, y *int) { // ERROR "live at entry to ddd1: x y$" func ddd1(x, y *int) { // ERROR "live at entry to ddd1: x y$"
ddd2(x, y) // ERROR "live at call to ddd2: .autotmp_[0-9]+$" ddd2(x, y) // ERROR "stack object .autotmp_[0-9]+ \[2\]\*int$"
printnl() printnl()
// Note: no .?autotmp live at printnl. See issue 16996. // Note: no .?autotmp live at printnl. See issue 16996.
} }

15
test/live2.go
View File

@ -10,7 +10,6 @@
package main package main
// issue 8142: lost 'addrtaken' bit on inlined variables. // issue 8142: lost 'addrtaken' bit on inlined variables.
// no inlining in this test, so just checking that non-inlined works.
func printnl() func printnl()
@ -28,15 +27,15 @@ func newT40() *T40 {
} }
func bad40() { func bad40() {
t := newT40() // ERROR "live at call to makemap: .autotmp_[0-9]+ ret$" t := newT40() // ERROR "live at call to makemap: ret$" "stack object ret T40$" "stack object .autotmp_[0-9]+ map.hdr\[int\]int$"
printnl() // ERROR "live at call to printnl: .autotmp_[0-9]+ ret$" printnl() // ERROR "live at call to printnl: ret$"
useT40(t) // ERROR "live at call to useT40: .autotmp_[0-9]+ ret$" useT40(t)
} }
func good40() { func good40() {
ret := T40{} ret := T40{} // ERROR "stack object ret T40$"
ret.m = make(map[int]int, 42) // ERROR "live at call to makemap: .autotmp_[0-9]+ ret$" ret.m = make(map[int]int, 42) // ERROR "live at call to makemap: ret$" "stack object .autotmp_[0-9]+ map.hdr\[int\]int$"
t := &ret t := &ret
printnl() // ERROR "live at call to printnl: .autotmp_[0-9]+ ret$" printnl() // ERROR "live at call to printnl: ret$"
useT40(t) // ERROR "live at call to useT40: .autotmp_[0-9]+ ret$" useT40(t)
} }

8
test/live_syscall.go
View File

@ -19,22 +19,22 @@ func f(uintptr) // ERROR "f assuming arg#1 is unsafe uintptr"
func g() { func g() {
var t int var t int
f(uintptr(unsafe.Pointer(&t))) // ERROR "live at call to f: .?autotmp" "g &t does not escape" f(uintptr(unsafe.Pointer(&t))) // ERROR "live at call to f: .?autotmp" "g &t does not escape" "stack object .autotmp_[0-9]+ unsafe.Pointer$"
} }
func h() { func h() {
var v int var v int
syscall.Syscall(0, 1, uintptr(unsafe.Pointer(&v)), 2) // ERROR "live at call to Syscall: .?autotmp" "h &v does not escape" syscall.Syscall(0, 1, uintptr(unsafe.Pointer(&v)), 2) // ERROR "live at call to Syscall: .?autotmp" "h &v does not escape" "stack object .autotmp_[0-9]+ unsafe.Pointer$"
} }
func i() { func i() {
var t int var t int
p := unsafe.Pointer(&t) // ERROR "i &t does not escape" p := unsafe.Pointer(&t) // ERROR "i &t does not escape"
f(uintptr(p)) // ERROR "live at call to f: .?autotmp" f(uintptr(p)) // ERROR "live at call to f: .?autotmp" "stack object .autotmp_[0-9]+ unsafe.Pointer$"
} }
func j() { func j() {
var v int var v int
p := unsafe.Pointer(&v) // ERROR "j &v does not escape" p := unsafe.Pointer(&v) // ERROR "j &v does not escape"
syscall.Syscall(0, 1, uintptr(p), 2) // ERROR "live at call to Syscall: .?autotmp" syscall.Syscall(0, 1, uintptr(p), 2) // ERROR "live at call to Syscall: .?autotmp" "stack object .autotmp_[0-9]+ unsafe.Pointer$"
} }

57
test/stackobj.go Normal file
View File

@ -0,0 +1,57 @@
// run
// Copyright 2018 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 main
import (
"fmt"
"runtime"
)
type HeapObj [8]int64
type StkObj struct {
h *HeapObj
}
var n int
var c int = -1
func gc() {
// encourage heap object to be collected, and have its finalizer run.
runtime.GC()
runtime.GC()
runtime.GC()
n++
}
func main() {
f()
gc() // prior to stack objects, heap object is not collected until here
if c < 0 {
panic("heap object never collected")
}
if c != 1 {
panic(fmt.Sprintf("expected collection at phase 1, got phase %d", c))
}
}
func f() {
var s StkObj
s.h = new(HeapObj)
runtime.SetFinalizer(s.h, func(h *HeapObj) {
// Remember at what phase the heap object was collected.
c = n
})
g(&s)
gc()
}
func g(s *StkObj) {
gc() // heap object is still live here
runtime.KeepAlive(s)
gc() // heap object should be collected here
}

93
test/stackobj3.go Normal file
View File

@ -0,0 +1,93 @@
// run
// Copyright 2018 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.
// This test makes sure that ambiguously live arguments work correctly.
package main
import (
"runtime"
)
type HeapObj [8]int64
type StkObj struct {
h *HeapObj
}
var n int
var c int = -1
func gc() {
// encourage heap object to be collected, and have its finalizer run.
runtime.GC()
runtime.GC()
runtime.GC()
n++
}
var null StkObj
var sink *HeapObj
//go:noinline
func use(p *StkObj) {
}
//go:noinline
func f(s StkObj, b bool) {
var p *StkObj
if b {
p = &s
} else {
p = &null
}
// use is required here to prevent the conditional
// code above from being executed after the first gc() call.
use(p)
// If b==false, h should be collected here.
gc() // 0
sink = p.h
gc() // 1
sink = nil
// If b==true, h should be collected here.
gc() // 2
}
func fTrue() {
var s StkObj
s.h = new(HeapObj)
c = -1
n = 0
runtime.SetFinalizer(s.h, func(h *HeapObj) {
// Remember at what phase the heap object was collected.
c = n
})
f(s, true)
if c != 2 {
panic("bad liveness")
}
}
func fFalse() {
var s StkObj
s.h = new(HeapObj)
c = -1
n = 0
runtime.SetFinalizer(s.h, func(h *HeapObj) {
// Remember at what phase the heap object was collected.
c = n
})
f(s, false)
if c != 0 {
panic("bad liveness")
}
}
func main() {
fTrue()
fFalse()
}

8
test/uintptrescapes2.go
View File

@ -30,14 +30,14 @@ func F4(...uintptr) {} // ERROR "escaping ...uintptr"
func G() { func G() {
var t int // ERROR "moved to heap" var t int // ERROR "moved to heap"
F1(uintptr(unsafe.Pointer(&t))) // ERROR "live at call to F1: .?autotmp" "&t escapes to heap" F1(uintptr(unsafe.Pointer(&t))) // ERROR "live at call to F1: .?autotmp" "&t escapes to heap" "stack object .autotmp_[0-9]+ unsafe.Pointer$"
var t2 int // ERROR "moved to heap" var t2 int // ERROR "moved to heap"
F3(uintptr(unsafe.Pointer(&t2))) // ERROR "live at call to F3: .?autotmp" "&t2 escapes to heap" F3(uintptr(unsafe.Pointer(&t2))) // ERROR "live at call to F3: .?autotmp" "&t2 escapes to heap" "stack object .autotmp_[0-9]+ unsafe.Pointer$"
} }
func H() { func H() {
var v int // ERROR "moved to heap" var v int // ERROR "moved to heap"
F2(0, 1, uintptr(unsafe.Pointer(&v)), 2) // ERROR "live at call to newobject: .?autotmp" "live at call to F2: .?autotmp" "escapes to heap" F2(0, 1, uintptr(unsafe.Pointer(&v)), 2) // ERROR "live at call to newobject: .?autotmp" "live at call to F2: .?autotmp" "escapes to heap" "stack object .autotmp_[0-9]+ unsafe.Pointer$"
var v2 int // ERROR "moved to heap" var v2 int // ERROR "moved to heap"
F4(0, 1, uintptr(unsafe.Pointer(&v2)), 2) // ERROR "live at call to newobject: .?autotmp" "live at call to F4: .?autotmp" "escapes to heap" F4(0, 1, uintptr(unsafe.Pointer(&v2)), 2) // ERROR "live at call to newobject: .?autotmp" "live at call to F4: .?autotmp" "escapes to heap" "stack object .autotmp_[0-9]+ unsafe.Pointer$"
} }