cmd/compile: escape analysis, don't always escape variadic args

Turns out the summary information for the ... args was
already correctly computed, all that lacked was to make
use of it and correct tests that documented our prior
deficiencies.

Fixes #12006

Change-Id: Ie8adfab7547f179391d470679598f0904aabf9f7
Reviewed-on: https://go-review.googlesource.com/15200
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
This commit is contained in:
David Chase 2015-09-30 14:41:00 -04:00
parent f78a4c84ac
commit f7a39a54e9
4 changed files with 221 additions and 44 deletions

View file

@ -951,6 +951,7 @@ func escassign(e *EscState, dst *Node, src *Node) {
OMAPLIT,
OSTRUCTLIT,
OPTRLIT,
ODDDARG,
OCALLPART:
break
@ -1456,8 +1457,9 @@ func esccall(e *EscState, n *Node, up *Node) {
}
}
var src *Node
for t := getinargx(fntype).Type; ll != nil; ll = ll.Next {
src := ll.N
src = ll.N
if t.Isddd && !n.Isddd {
// Introduce ODDDARG node to represent ... allocation.
src = Nod(ODDDARG, nil, nil)
@ -1498,17 +1500,17 @@ func esccall(e *EscState, n *Node, up *Node) {
}
if src != ll.N {
// This occurs when function parameter type Isddd and n not Isddd
break
}
t = t.Down
}
// "..." arguments are untracked
for ; ll != nil; ll = ll.Next {
escassign(e, &e.theSink, ll.N)
if Debug['m'] > 2 {
fmt.Printf("%v::esccall:: ... <- %v, untracked\n", Ctxt.Line(int(lineno)), Nconv(ll.N, obj.FmtShort))
fmt.Printf("%v::esccall:: ... <- %v\n", Ctxt.Line(int(lineno)), Nconv(ll.N, obj.FmtShort))
}
escassign(e, src, ll.N) // args to slice
}
}
@ -1694,6 +1696,16 @@ func escwalk(e *EscState, level Level, dst *Node, src *Node) {
case OAPPEND:
escwalk(e, level, dst, src.List.N)
case ODDDARG:
if leaks {
src.Esc = EscHeap
if Debug['m'] != 0 {
Warnl(int(src.Lineno), "%v escapes to heap", Nconv(src, obj.FmtShort))
}
}
// similar to a slice arraylit and its args.
level = level.dec()
case OARRAYLIT:
if Isfixedarray(src.Type) {
break
@ -1704,8 +1716,7 @@ func escwalk(e *EscState, level Level, dst *Node, src *Node) {
fallthrough
case ODDDARG,
OMAKECHAN,
case OMAKECHAN,
OMAKEMAP,
OMAKESLICE,
OARRAYRUNESTR,

View file

@ -620,15 +620,15 @@ func myprint1(y *int, x ...interface{}) *interface{} { // ERROR "leaking param:
}
func foo75(z *int) { // ERROR "foo75 z does not escape$"
myprint(z, 1, 2, 3) // ERROR "1 escapes to heap$" "2 escapes to heap$" "3 escapes to heap$" "foo75 ... argument does not escape$"
myprint(z, 1, 2, 3) // ERROR "1 does not escape" "2 does not escape" "3 does not escape" "foo75 ... argument does not escape$"
}
func foo75a(z *int) { // ERROR "foo75a z does not escape$"
myprint1(z, 1, 2, 3) // ERROR "1 escapes to heap$" "2 escapes to heap$" "3 escapes to heap$" "foo75a ... argument does not escape$"
myprint1(z, 1, 2, 3) // ERROR "1 does not escape" "2 does not escape" "3 does not escape" "foo75a ... argument does not escape$"
}
func foo75esc(z *int) { // ERROR "leaking param: z$"
gxx = myprint(z, 1, 2, 3) // ERROR "1 escapes to heap$" "2 escapes to heap$" "3 escapes to heap$" "foo75esc ... argument does not escape$"
gxx = myprint(z, 1, 2, 3) // ERROR "1 does not escape" "2 does not escape" "3 does not escape" "foo75esc ... argument does not escape$"
}
func foo75aesc(z *int) { // ERROR "foo75aesc z does not escape$"
@ -640,30 +640,28 @@ func foo75aesc1(z *int) { // ERROR "foo75aesc1 z does not escape$"
sink = myprint1(z, 1, 2, 3) // ERROR "... argument escapes to heap$" "1 escapes to heap$" "2 escapes to heap$" "3 escapes to heap$" "myprint1\(z, 1, 2, 3\) escapes to heap$"
}
// BAD: z does not escape here
func foo76(z *int) { // ERROR "leaking param: z$"
myprint(nil, z) // ERROR "foo76 ... argument does not escape$" "z escapes to heap$"
func foo76(z *int) { // ERROR "z does not escape"
myprint(nil, z) // ERROR "foo76 ... argument does not escape$" "z does not escape"
}
// BAD: z does not escape here
func foo76a(z *int) { // ERROR "leaking param: z$"
myprint1(nil, z) // ERROR "foo76a ... argument does not escape$" "z escapes to heap$"
func foo76a(z *int) { // ERROR "z does not escape"
myprint1(nil, z) // ERROR "foo76a ... argument does not escape$" "z does not escape"
}
func foo76b() {
myprint(nil, 1, 2, 3) // ERROR "1 escapes to heap$" "2 escapes to heap$" "3 escapes to heap$" "foo76b ... argument does not escape$"
myprint(nil, 1, 2, 3) // ERROR "1 does not escape" "2 does not escape" "3 does not escape" "foo76b ... argument does not escape$"
}
func foo76c() {
myprint1(nil, 1, 2, 3) // ERROR "1 escapes to heap$" "2 escapes to heap$" "3 escapes to heap$" "foo76c ... argument does not escape$"
myprint1(nil, 1, 2, 3) // ERROR "1 does not escape" "2 does not escape" "3 does not escape" "foo76c ... argument does not escape$"
}
func foo76d() {
defer myprint(nil, 1, 2, 3) // ERROR "1 escapes to heap$" "2 escapes to heap$" "3 escapes to heap$" "foo76d ... argument does not escape$"
defer myprint(nil, 1, 2, 3) // ERROR "1 does not escape" "2 does not escape" "3 does not escape" "foo76d ... argument does not escape$"
}
func foo76e() {
defer myprint1(nil, 1, 2, 3) // ERROR "1 escapes to heap$" "2 escapes to heap$" "3 escapes to heap$" "foo76e ... argument does not escape$"
defer myprint1(nil, 1, 2, 3) // ERROR "1 does not escape" "2 does not escape" "3 does not escape" "foo76e ... argument does not escape$"
}
func foo76f() {
@ -697,13 +695,11 @@ func foo77c(z []interface{}) { // ERROR "leaking param: z$"
}
func dotdotdot() {
// BAD: i should not escape here
i := 0 // ERROR "moved to heap: i$"
myprint(nil, &i) // ERROR "&i escapes to heap$" "dotdotdot ... argument does not escape$"
i := 0
myprint(nil, &i) // ERROR "&i does not escape" "dotdotdot ... argument does not escape$"
// BAD: j should not escape here
j := 0 // ERROR "moved to heap: j$"
myprint1(nil, &j) // ERROR "&j escapes to heap$" "dotdotdot ... argument does not escape$"
j := 0
myprint1(nil, &j) // ERROR "&j does not escape" "dotdotdot ... argument does not escape$"
}
func foo78(z int) *int { // ERROR "moved to heap: z$"

View file

@ -620,15 +620,15 @@ func myprint1(y *int, x ...interface{}) *interface{} { // ERROR "leaking param:
}
func foo75(z *int) { // ERROR "foo75 z does not escape$"
myprint(z, 1, 2, 3) // ERROR "1 escapes to heap$" "2 escapes to heap$" "3 escapes to heap$" "foo75 ... argument does not escape$"
myprint(z, 1, 2, 3) // ERROR "1 does not escape" "2 does not escape" "3 does not escape" "foo75 ... argument does not escape$"
}
func foo75a(z *int) { // ERROR "foo75a z does not escape$"
myprint1(z, 1, 2, 3) // ERROR "1 escapes to heap$" "2 escapes to heap$" "3 escapes to heap$" "foo75a ... argument does not escape$"
myprint1(z, 1, 2, 3) // ERROR "1 does not escape" "2 does not escape" "3 does not escape" "foo75a ... argument does not escape$"
}
func foo75esc(z *int) { // ERROR "leaking param: z$"
gxx = myprint(z, 1, 2, 3) // ERROR "1 escapes to heap$" "2 escapes to heap$" "3 escapes to heap$" "foo75esc ... argument does not escape$"
gxx = myprint(z, 1, 2, 3) // ERROR "1 does not escape" "2 does not escape" "3 does not escape" "foo75esc ... argument does not escape$"
}
func foo75aesc(z *int) { // ERROR "foo75aesc z does not escape$"
@ -640,30 +640,28 @@ func foo75aesc1(z *int) { // ERROR "foo75aesc1 z does not escape$"
sink = myprint1(z, 1, 2, 3) // ERROR "... argument escapes to heap$" "1 escapes to heap$" "2 escapes to heap$" "3 escapes to heap$" "myprint1\(z, 1, 2, 3\) escapes to heap$"
}
// BAD: z does not escape here
func foo76(z *int) { // ERROR "leaking param: z$"
myprint(nil, z) // ERROR "foo76 ... argument does not escape$" "z escapes to heap$"
func foo76(z *int) { // ERROR "z does not escape"
myprint(nil, z) // ERROR "foo76 ... argument does not escape$" "z does not escape"
}
// BAD: z does not escape here
func foo76a(z *int) { // ERROR "leaking param: z$"
myprint1(nil, z) // ERROR "foo76a ... argument does not escape$" "z escapes to heap$"
func foo76a(z *int) { // ERROR "z does not escape"
myprint1(nil, z) // ERROR "foo76a ... argument does not escape$" "z does not escape"
}
func foo76b() {
myprint(nil, 1, 2, 3) // ERROR "1 escapes to heap$" "2 escapes to heap$" "3 escapes to heap$" "foo76b ... argument does not escape$"
myprint(nil, 1, 2, 3) // ERROR "1 does not escape" "2 does not escape" "3 does not escape" "foo76b ... argument does not escape$"
}
func foo76c() {
myprint1(nil, 1, 2, 3) // ERROR "1 escapes to heap$" "2 escapes to heap$" "3 escapes to heap$" "foo76c ... argument does not escape$"
myprint1(nil, 1, 2, 3) // ERROR "1 does not escape" "2 does not escape" "3 does not escape" "foo76c ... argument does not escape$"
}
func foo76d() {
defer myprint(nil, 1, 2, 3) // ERROR "1 escapes to heap$" "2 escapes to heap$" "3 escapes to heap$" "foo76d ... argument does not escape$"
defer myprint(nil, 1, 2, 3) // ERROR "1 does not escape" "2 does not escape" "3 does not escape" "foo76d ... argument does not escape$"
}
func foo76e() {
defer myprint1(nil, 1, 2, 3) // ERROR "1 escapes to heap$" "2 escapes to heap$" "3 escapes to heap$" "foo76e ... argument does not escape$"
defer myprint1(nil, 1, 2, 3) // ERROR "1 does not escape" "2 does not escape" "3 does not escape" "foo76e ... argument does not escape$"
}
func foo76f() {
@ -697,13 +695,11 @@ func foo77c(z []interface{}) { // ERROR "leaking param: z$"
}
func dotdotdot() {
// BAD: i should not escape here
i := 0 // ERROR "moved to heap: i$"
myprint(nil, &i) // ERROR "&i escapes to heap$" "dotdotdot ... argument does not escape$"
i := 0
myprint(nil, &i) // ERROR "&i does not escape" "dotdotdot ... argument does not escape$"
// BAD: j should not escape here
j := 0 // ERROR "moved to heap: j$"
myprint1(nil, &j) // ERROR "&j escapes to heap$" "dotdotdot ... argument does not escape$"
j := 0
myprint1(nil, &j) // ERROR "&j does not escape" "dotdotdot ... argument does not escape$"
}
func foo78(z int) *int { // ERROR "moved to heap: z$"

View file

@ -0,0 +1,174 @@
// errorcheck -0 -m -l
// Copyright 2015 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Test escape analysis through ... parameters.
package foo
func FooN(vals ...*int) (s int) { // ERROR "FooN vals does not escape"
for _, v := range vals {
s += *v
}
return s
}
// Append forces heap allocation and copies entries in vals to heap, therefore they escape to heap.
func FooNx(x *int, vals ...*int) (s int) { // ERROR "leaking param: x" "leaking param content: vals"
vals = append(vals, x)
return FooN(vals...)
}
var sink []*int
func FooNy(x *int, vals ...*int) (s int) { // ERROR "leaking param: x" "leaking param: vals" "leaking param content: vals"
vals = append(vals, x)
sink = vals
return FooN(vals...)
}
func FooNz(vals ...*int) (s int) { // ERROR "leaking param: vals"
sink = vals
return FooN(vals...)
}
func TFooN() {
for i := 0; i < 1000; i++ {
var i, j int
FooN(&i, &j) // ERROR "TFooN &i does not escape" "TFooN &j does not escape" "TFooN ... argument does not escape"
}
}
func TFooNx() {
for i := 0; i < 1000; i++ {
var i, j, k int // ERROR "moved to heap: i" "moved to heap: j" "moved to heap: k"
FooNx(&k, &i, &j) // ERROR "&k escapes to heap" "&i escapes to heap" "&j escapes to heap" "TFooNx ... argument does not escape"
}
}
func TFooNy() {
for i := 0; i < 1000; i++ {
var i, j, k int // ERROR "moved to heap: i" "moved to heap: j" "moved to heap: k"
FooNy(&k, &i, &j) // ERROR "&i escapes to heap" "&j escapes to heap" "&k escapes to heap" "... argument escapes to heap"
}
}
func TFooNz() {
for i := 0; i < 1000; i++ {
var i, j int // ERROR "moved to heap: i" "moved to heap: j"
FooNz(&i, &j) // ERROR "&i escapes to heap" "&j escapes to heap" "... argument escapes to heap"
}
}
var isink *int32
func FooI(args ...interface{}) { // ERROR "leaking param content: args"
for i := 0; i < len(args); i++ {
switch x := args[i].(type) {
case nil:
println("is nil")
case int32:
println("is int32")
case *int32:
println("is *int32")
isink = x
case string:
println("is string")
}
}
}
func TFooI() {
a := int32(1) // ERROR "moved to heap: a"
b := "cat"
c := &a // ERROR "&a escapes to heap"
FooI(a, b, c) // ERROR "a escapes to heap" "b escapes to heap" "c escapes to heap" "TFooI ... argument does not escape"
}
func FooJ(args ...interface{}) *int32 { // ERROR "leaking param: args to result ~r1 level=1"
for i := 0; i < len(args); i++ {
switch x := args[i].(type) {
case nil:
println("is nil")
case int32:
println("is int32")
case *int32:
println("is *int32")
return x
case string:
println("is string")
}
}
return nil
}
func TFooJ1() {
a := int32(1)
b := "cat"
c := &a // ERROR "TFooJ1 &a does not escape"
FooJ(a, b, c) // ERROR "TFooJ1 a does not escape" "TFooJ1 b does not escape" "TFooJ1 c does not escape" "TFooJ1 ... argument does not escape"
}
func TFooJ2() {
a := int32(1) // ERROR "moved to heap: a"
b := "cat"
c := &a // ERROR "&a escapes to heap"
isink = FooJ(a, b, c) // ERROR "a escapes to heap" "b escapes to heap" "c escapes to heap" "TFooJ2 ... argument does not escape"
}
type fakeSlice struct {
l int
a *[4]interface{}
}
func FooK(args fakeSlice) *int32 { // ERROR "leaking param: args to result ~r1 level=1"
for i := 0; i < args.l; i++ {
switch x := (*args.a)[i].(type) {
case nil:
println("is nil")
case int32:
println("is int32")
case *int32:
println("is *int32")
return x
case string:
println("is string")
}
}
return nil
}
func TFooK2() {
a := int32(1) // ERROR "moved to heap: a"
b := "cat"
c := &a // ERROR "&a escapes to heap"
fs := fakeSlice{3, &[4]interface{}{a, b, c, nil}} // ERROR "a escapes to heap" "b escapes to heap" "c escapes to heap" "TFooK2 &\[4\]interface {} literal does not escape"
isink = FooK(fs)
}
func FooL(args []interface{}) *int32 { // ERROR "leaking param: args to result ~r1 level=1"
for i := 0; i < len(args); i++ {
switch x := args[i].(type) {
case nil:
println("is nil")
case int32:
println("is int32")
case *int32:
println("is *int32")
return x
case string:
println("is string")
}
}
return nil
}
func TFooL2() {
a := int32(1) // ERROR "moved to heap: a"
b := "cat"
c := &a // ERROR "&a escapes to heap"
s := []interface{}{a, b, c} // ERROR "a escapes to heap" "b escapes to heap" "c escapes to heap" "TFooL2 \[\]interface {} literal does not escape"
isink = FooL(s)
}