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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>
38 lines
715 B
Go
38 lines
715 B
Go
// errorcheck -0 -l -m
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// Copyright 2017 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Issue 21709: range expression overly escapes.
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package p
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type S struct{}
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func (s *S) Inc() {} // ERROR "s does not escape"
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var N int
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func F1() {
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var s S
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for i := 0; i < N; i++ {
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fs := []func(){ // ERROR "\[\]func\(\) literal does not escape"
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s.Inc, // ERROR "s.Inc does not escape"
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}
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for _, f := range fs {
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f()
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}
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}
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}
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func F2() {
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var s S
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for i := 0; i < N; i++ {
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for _, f := range []func(){ // ERROR "\[\]func\(\) literal does not escape"
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s.Inc, // ERROR "s.Inc does not escape"
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} {
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f()
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}
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}
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}
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