mirror of
https://github.com/golang/go
synced 2024-11-24 13:20:15 -07:00
c39918a049
Several of our current write barrier elision optimizations are invalid with the hybrid barrier. Eliding the hybrid barrier requires that *both* the current and new pointer be already shaded and, since we don't have the flow analysis to figure out anything about the slot's current value, for now we have to just disable several of these optimizations. This has a slight impact on binary size. On linux/amd64, the go tool binary increases by 0.7% and the compile binary increases by 1.5%. It also has a slight impact on performance, as one would expect. We'll win some of this back in subsequent commits. name old time/op new time/op delta BinaryTree17-12 2.38s ± 1% 2.40s ± 1% +0.82% (p=0.000 n=18+20) Fannkuch11-12 2.84s ± 1% 2.70s ± 0% -4.97% (p=0.000 n=18+18) FmtFprintfEmpty-12 44.2ns ± 1% 46.4ns ± 2% +4.89% (p=0.000 n=16+18) FmtFprintfString-12 131ns ± 0% 134ns ± 1% +2.05% (p=0.000 n=12+19) FmtFprintfInt-12 114ns ± 1% 117ns ± 1% +3.26% (p=0.000 n=19+20) FmtFprintfIntInt-12 176ns ± 1% 181ns ± 1% +3.25% (p=0.000 n=20+20) FmtFprintfPrefixedInt-12 185ns ± 1% 190ns ± 1% +2.77% (p=0.000 n=19+18) FmtFprintfFloat-12 249ns ± 1% 254ns ± 1% +1.71% (p=0.000 n=18+20) FmtManyArgs-12 747ns ± 1% 743ns ± 1% -0.58% (p=0.000 n=19+18) GobDecode-12 6.57ms ± 1% 6.61ms ± 0% +0.73% (p=0.000 n=19+20) GobEncode-12 5.58ms ± 1% 5.60ms ± 0% +0.27% (p=0.001 n=18+18) Gzip-12 223ms ± 1% 223ms ± 1% ~ (p=0.351 n=19+20) Gunzip-12 37.9ms ± 0% 37.9ms ± 1% ~ (p=0.095 n=16+20) HTTPClientServer-12 77.8µs ± 1% 78.5µs ± 1% +0.97% (p=0.000 n=19+20) JSONEncode-12 14.8ms ± 1% 14.8ms ± 1% ~ (p=0.079 n=20+19) JSONDecode-12 53.7ms ± 1% 54.2ms ± 1% +0.92% (p=0.000 n=20+19) Mandelbrot200-12 3.81ms ± 1% 3.81ms ± 0% ~ (p=0.916 n=19+18) GoParse-12 3.19ms ± 1% 3.19ms ± 1% ~ (p=0.175 n=20+19) RegexpMatchEasy0_32-12 71.9ns ± 1% 70.6ns ± 1% -1.87% (p=0.000 n=19+20) RegexpMatchEasy0_1K-12 946ns ± 0% 944ns ± 0% -0.22% (p=0.000 n=19+16) RegexpMatchEasy1_32-12 67.3ns ± 2% 66.8ns ± 1% -0.72% (p=0.008 n=20+20) RegexpMatchEasy1_1K-12 374ns ± 1% 384ns ± 1% +2.69% (p=0.000 n=18+20) RegexpMatchMedium_32-12 107ns ± 1% 107ns ± 1% ~ (p=1.000 n=20+20) RegexpMatchMedium_1K-12 34.3µs ± 1% 34.6µs ± 1% +0.90% (p=0.000 n=20+20) RegexpMatchHard_32-12 1.78µs ± 1% 1.80µs ± 1% +1.45% (p=0.000 n=20+19) RegexpMatchHard_1K-12 53.6µs ± 0% 54.5µs ± 1% +1.52% (p=0.000 n=19+18) Revcomp-12 417ms ± 5% 391ms ± 1% -6.42% (p=0.000 n=16+19) Template-12 61.1ms ± 1% 64.2ms ± 0% +5.07% (p=0.000 n=19+20) TimeParse-12 302ns ± 1% 305ns ± 1% +0.90% (p=0.000 n=18+18) TimeFormat-12 319ns ± 1% 315ns ± 1% -1.25% (p=0.000 n=18+18) [Geo mean] 54.0µs 54.3µs +0.58% name old time/op new time/op delta XGarbage-12 2.24ms ± 2% 2.28ms ± 1% +1.68% (p=0.000 n=18+17) XHTTP-12 11.4µs ± 1% 11.6µs ± 2% +1.63% (p=0.000 n=18+18) XJSON-12 11.6ms ± 0% 12.5ms ± 0% +7.84% (p=0.000 n=18+17) Updates #17503. Change-Id: I1899f8e35662971e24bf692b517dfbe2b533c00c Reviewed-on: https://go-review.googlesource.com/31572 Reviewed-by: Keith Randall <khr@golang.org>
223 lines
4.4 KiB
Go
223 lines
4.4 KiB
Go
// errorcheck -0 -l -d=wb
|
|
|
|
// 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 where write barriers are and are not emitted.
|
|
|
|
package p
|
|
|
|
import "unsafe"
|
|
|
|
func f(x **byte, y *byte) {
|
|
*x = y // ERROR "write barrier"
|
|
|
|
z := y // no barrier
|
|
*x = z // ERROR "write barrier"
|
|
}
|
|
|
|
func f1(x *[]byte, y []byte) {
|
|
*x = y // ERROR "write barrier"
|
|
|
|
z := y // no barrier
|
|
*x = z // ERROR "write barrier"
|
|
}
|
|
|
|
func f1a(x *[]byte, y *[]byte) {
|
|
*x = *y // ERROR "write barrier"
|
|
|
|
z := *y // no barrier
|
|
*x = z // ERROR "write barrier"
|
|
}
|
|
|
|
func f2(x *interface{}, y interface{}) {
|
|
*x = y // ERROR "write barrier"
|
|
|
|
z := y // no barrier
|
|
*x = z // ERROR "write barrier"
|
|
}
|
|
|
|
func f2a(x *interface{}, y *interface{}) {
|
|
*x = *y // ERROR "write barrier"
|
|
|
|
z := y // no barrier
|
|
*x = z // ERROR "write barrier"
|
|
}
|
|
|
|
func f3(x *string, y string) {
|
|
*x = y // ERROR "write barrier"
|
|
|
|
z := y // no barrier
|
|
*x = z // ERROR "write barrier"
|
|
}
|
|
|
|
func f3a(x *string, y *string) {
|
|
*x = *y // ERROR "write barrier"
|
|
|
|
z := *y // no barrier
|
|
*x = z // ERROR "write barrier"
|
|
}
|
|
|
|
func f4(x *[2]string, y [2]string) {
|
|
*x = y // ERROR "write barrier"
|
|
|
|
z := y // no barrier
|
|
*x = z // ERROR "write barrier"
|
|
}
|
|
|
|
func f4a(x *[2]string, y *[2]string) {
|
|
*x = *y // ERROR "write barrier"
|
|
|
|
z := *y // no barrier
|
|
*x = z // ERROR "write barrier"
|
|
}
|
|
|
|
type T struct {
|
|
X *int
|
|
Y int
|
|
M map[int]int
|
|
}
|
|
|
|
func f5(t, u *T) {
|
|
t.X = &u.Y // ERROR "write barrier"
|
|
}
|
|
|
|
func f6(t *T) {
|
|
t.M = map[int]int{1: 2} // ERROR "write barrier"
|
|
}
|
|
|
|
func f7(x, y *int) []*int {
|
|
var z [3]*int
|
|
i := 0
|
|
z[i] = x // ERROR "write barrier"
|
|
i++
|
|
z[i] = y // ERROR "write barrier"
|
|
i++
|
|
return z[:i]
|
|
}
|
|
|
|
func f9(x *interface{}, v *byte) {
|
|
*x = v // ERROR "write barrier"
|
|
}
|
|
|
|
func f10(x *byte, f func(interface{})) {
|
|
f(x)
|
|
}
|
|
|
|
func f11(x *unsafe.Pointer, y unsafe.Pointer) {
|
|
*x = unsafe.Pointer(uintptr(y) + 1) // ERROR "write barrier"
|
|
}
|
|
|
|
func f12(x []*int, y *int) []*int {
|
|
// write barrier for storing y in x's underlying array
|
|
x = append(x, y) // ERROR "write barrier"
|
|
return x
|
|
}
|
|
|
|
func f12a(x []int, y int) []int {
|
|
// y not a pointer, so no write barriers in this function
|
|
x = append(x, y)
|
|
return x
|
|
}
|
|
|
|
func f13(x []int, y *[]int) {
|
|
*y = append(x, 1) // ERROR "write barrier"
|
|
}
|
|
|
|
func f14(y *[]int) {
|
|
*y = append(*y, 1) // ERROR "write barrier"
|
|
}
|
|
|
|
type T1 struct {
|
|
X *int
|
|
}
|
|
|
|
func f15(x []T1, y T1) []T1 {
|
|
return append(x, y) // ERROR "write barrier"
|
|
}
|
|
|
|
type T8 struct {
|
|
X [8]*int
|
|
}
|
|
|
|
func f16(x []T8, y T8) []T8 {
|
|
return append(x, y) // ERROR "write barrier"
|
|
}
|
|
|
|
func t1(i interface{}) **int {
|
|
// From issue 14306, make sure we have write barriers in a type switch
|
|
// where the assigned variable escapes.
|
|
switch x := i.(type) { // ERROR "write barrier"
|
|
case *int:
|
|
return &x
|
|
}
|
|
switch y := i.(type) { // no write barrier here
|
|
case **int:
|
|
return y
|
|
}
|
|
return nil
|
|
}
|
|
|
|
type T17 struct {
|
|
f func(*T17)
|
|
}
|
|
|
|
func f17(x *T17) {
|
|
// Originally from golang.org/issue/13901, but the hybrid
|
|
// barrier requires both to have barriers.
|
|
x.f = f17 // ERROR "write barrier"
|
|
x.f = func(y *T17) { *y = *x } // ERROR "write barrier"
|
|
}
|
|
|
|
type T18 struct {
|
|
a []int
|
|
s string
|
|
}
|
|
|
|
func f18(p *T18, x *[]int) {
|
|
p.a = p.a[:5] // no barrier
|
|
*x = (*x)[0:5] // no barrier
|
|
p.a = p.a[3:5] // ERROR "write barrier"
|
|
p.a = p.a[1:2:3] // ERROR "write barrier"
|
|
p.s = p.s[8:9] // ERROR "write barrier"
|
|
*x = (*x)[3:5] // ERROR "write barrier"
|
|
}
|
|
|
|
func f19(x, y *int, i int) int {
|
|
// Constructing a temporary slice on the stack should not
|
|
// require any write barriers. See issue 14263.
|
|
a := []*int{x, y} // no barrier
|
|
return *a[i]
|
|
}
|
|
|
|
func f20(x, y *int, i int) []*int {
|
|
// ... but if that temporary slice escapes, then the
|
|
// write barriers are necessary.
|
|
a := []*int{x, y} // ERROR "write barrier"
|
|
return a
|
|
}
|
|
|
|
var x21 *int
|
|
var y21 struct {
|
|
x *int
|
|
}
|
|
var z21 int
|
|
|
|
func f21(x *int) {
|
|
// Global -> heap pointer updates must have write barriers.
|
|
x21 = x // ERROR "write barrier"
|
|
y21.x = x // ERROR "write barrier"
|
|
x21 = &z21 // ERROR "write barrier"
|
|
y21.x = &z21 // ERROR "write barrier"
|
|
y21 = struct{ x *int }{x} // ERROR "write barrier"
|
|
}
|
|
|
|
func f22(x *int) (y *int) {
|
|
// pointer write on stack should have no write barrier.
|
|
// this is a case that the frontend failed to eliminate.
|
|
p := &y
|
|
*p = x // no barrier
|
|
return
|
|
}
|