mirror of
https://github.com/golang/go
synced 2024-11-08 18:46:16 -07:00
2a2423bd05
Previously for a method value "x.M", we always flowed x directly to the heap, which led to the receiver argument generally needing to be heap allocated. This CL changes it to flow x to the closure and M's receiver parameter. This allows receiver arguments to be stack allocated as long as (1) the closure never escapes, *and* (2) method doesn't leak its receiver parameter. Within the standard library, this allows a handful of objects to be stack allocated instead. Listed here are diagnostics that were previously emitted by "go build -gcflags=-m std cmd" that are no longer emitted: archive/tar/writer.go:118:6: moved to heap: f archive/tar/writer.go:208:6: moved to heap: f archive/tar/writer.go:248:6: moved to heap: f cmd/compile/internal/gc/initorder.go:252:2: moved to heap: d cmd/compile/internal/gc/initorder.go:75:2: moved to heap: s cmd/go/internal/generate/generate.go:206:7: &Generator literal escapes to heap cmd/internal/obj/arm64/asm7.go:910:2: moved to heap: c cmd/internal/obj/mips/asm0.go:415:2: moved to heap: c cmd/internal/obj/pcln.go:294:22: new(pcinlineState) escapes to heap cmd/internal/obj/s390x/asmz.go:459:2: moved to heap: c crypto/tls/handshake_server.go:56:2: moved to heap: hs Thanks to Cuong Manh Le for help coming up with this solution. Fixes #27557. Change-Id: I8c85d671d07fb9b53e11d2dd05949a34dbbd7e17 Reviewed-on: https://go-review.googlesource.com/c/go/+/228263 Run-TryBot: Matthew Dempsky <mdempsky@google.com> Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com> Reviewed-by: Cherry Zhang <cherryyz@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org>
42 lines
946 B
Go
42 lines
946 B
Go
// errorcheck -0 -l -m
|
|
|
|
// Copyright 2019 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
|
|
|
|
var sink interface{}
|
|
|
|
func _() {
|
|
var t T
|
|
f := t.noescape // ERROR "t.noescape does not escape"
|
|
f()
|
|
}
|
|
|
|
func _() {
|
|
var t T // ERROR "moved to heap"
|
|
f := t.escape // ERROR "t.escape does not escape"
|
|
f()
|
|
}
|
|
|
|
func _() {
|
|
var t T // ERROR "moved to heap"
|
|
f := t.returns // ERROR "t.returns does not escape"
|
|
sink = f()
|
|
}
|
|
|
|
type T struct{}
|
|
|
|
func (t *T) noescape() {} // ERROR "t does not escape"
|
|
func (t *T) escape() { sink = t } // ERROR "leaking param: t$"
|
|
func (t *T) returns() *T { return t } // ERROR "leaking param: t to result ~r0 level=0"
|
|
|
|
func (t *T) recursive() { // ERROR "leaking param: t$"
|
|
sink = t
|
|
|
|
var t2 T // ERROR "moved to heap"
|
|
f := t2.recursive // ERROR "t2.recursive does not escape"
|
|
f()
|
|
}
|