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go/test/fixedbugs/issue7921.go
Matthew Dempsky 12ee55ba7b [dev.regabi] cmd/compile: stop using Vargen for import/export
Historically, inline function bodies were exported as plain Go source
code, and symbol mangling was a convenient hack because it allowed
variables to be re-imported with largely the same names as they were
originally exported as.

However, nowadays we use a binary format that's more easily extended,
so we can simply serialize all of a function's declared objects up
front, and then refer to them by index later on. This also allows us
to easily report unmangled names all the time (e.g., error message
from issue7921.go).

Fixes #43633.

Change-Id: I46c88f5a47cb921f70ab140976ba9ddce38df216
Reviewed-on: https://go-review.googlesource.com/c/go/+/283193
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Dan Scales <danscales@google.com>
Trust: Dan Scales <danscales@google.com>
Trust: Matthew Dempsky <mdempsky@google.com>
2021-01-12 03:15:18 +00:00

58 lines
2.1 KiB
Go

// +build !gcflags_noopt
// errorcheck -0 -m
// 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 foo
import "bytes"
// In order to get desired results, we need a combination of
// both escape analysis and inlining.
func bufferNotEscape() string {
// b itself does not escape, only its buf field will be
// copied during String() call, but object "handle" itself
// can be stack-allocated.
var b bytes.Buffer
b.WriteString("123")
b.Write([]byte{'4'}) // ERROR "\[\]byte{...} does not escape$"
return b.String() // ERROR "inlining call to bytes.\(\*Buffer\).String$" "string\(bytes.b.buf\[bytes.b.off:\]\) escapes to heap$"
}
func bufferNoEscape2(xs []string) int { // ERROR "xs does not escape$"
b := bytes.NewBuffer(make([]byte, 0, 64)) // ERROR "&bytes.Buffer{...} does not escape$" "make\(\[\]byte, 0, 64\) does not escape$" "inlining call to bytes.NewBuffer$"
for _, x := range xs {
b.WriteString(x)
}
return b.Len() // ERROR "inlining call to bytes.\(\*Buffer\).Len$"
}
func bufferNoEscape3(xs []string) string { // ERROR "xs does not escape$"
b := bytes.NewBuffer(make([]byte, 0, 64)) // ERROR "&bytes.Buffer{...} does not escape$" "make\(\[\]byte, 0, 64\) does not escape$" "inlining call to bytes.NewBuffer$"
for _, x := range xs {
b.WriteString(x)
b.WriteByte(',')
}
return b.String() // ERROR "inlining call to bytes.\(\*Buffer\).String$" "string\(bytes.b.buf\[bytes.b.off:\]\) escapes to heap$"
}
func bufferNoEscape4() []byte {
var b bytes.Buffer
b.Grow(64) // ERROR "bufferNoEscape4 ignoring self-assignment in bytes.b.buf = bytes.b.buf\[:bytes.m\]$" "inlining call to bytes.\(\*Buffer\).Grow$"
useBuffer(&b)
return b.Bytes() // ERROR "inlining call to bytes.\(\*Buffer\).Bytes$"
}
func bufferNoEscape5() { // ERROR "can inline bufferNoEscape5$"
b := bytes.NewBuffer(make([]byte, 0, 128)) // ERROR "&bytes.Buffer{...} does not escape$" "make\(\[\]byte, 0, 128\) does not escape$" "inlining call to bytes.NewBuffer$"
useBuffer(b)
}
//go:noinline
func useBuffer(b *bytes.Buffer) { // ERROR "b does not escape$"
b.WriteString("1234")
}