mirror of
https://github.com/golang/go
synced 2024-11-24 19:00:13 -07:00
c33d45a898
During package initialization, the compiler tries to optimize:
var A = "foo"
var B = A
into
var A = "foo"
var B = "foo"
so that we can statically initialize both A and B and skip emitting
dynamic initialization code to assign "B = A".
However, this isn't safe in the presence of cmd/link's -X flag, which
might overwrite an initialized string-typed variable at link time. In
particular, if cmd/link changes A's static initialization, it won't
know it also needs to change B's static initialization.
To address this, this CL disables this optimization for string-typed
variables.
Fixes #34675.
Change-Id: I1c18f3b855f6d7114aeb39f96aaaf1b452b88236
Reviewed-on: https://go-review.googlesource.com/c/go/+/198657
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
71 lines
1.6 KiB
Go
71 lines
1.6 KiB
Go
// +build !nacl,!js
|
|
// run
|
|
|
|
// Copyright 2014 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.
|
|
|
|
// Run the linkx test.
|
|
|
|
package main
|
|
|
|
import (
|
|
"bytes"
|
|
"fmt"
|
|
"os"
|
|
"os/exec"
|
|
"strings"
|
|
)
|
|
|
|
func main() {
|
|
// test(" ") // old deprecated & removed syntax
|
|
test("=") // new syntax
|
|
}
|
|
|
|
func test(sep string) {
|
|
// Successful run
|
|
cmd := exec.Command("go", "run", "-ldflags=-X main.tbd"+sep+"hello -X main.overwrite"+sep+"trumped -X main.nosuchsymbol"+sep+"neverseen", "linkx.go")
|
|
var out, errbuf bytes.Buffer
|
|
cmd.Stdout = &out
|
|
cmd.Stderr = &errbuf
|
|
err := cmd.Run()
|
|
if err != nil {
|
|
fmt.Println(errbuf.String())
|
|
fmt.Println(out.String())
|
|
fmt.Println(err)
|
|
os.Exit(1)
|
|
}
|
|
|
|
want := "hello\nhello\nhello\ntrumped\ntrumped\ntrumped\n"
|
|
got := out.String()
|
|
if got != want {
|
|
fmt.Printf("got %q want %q\n", got, want)
|
|
os.Exit(1)
|
|
}
|
|
|
|
// Issue 8810
|
|
cmd = exec.Command("go", "run", "-ldflags=-X main.tbd", "linkx.go")
|
|
_, err = cmd.CombinedOutput()
|
|
if err == nil {
|
|
fmt.Println("-X linker flag should not accept keys without values")
|
|
os.Exit(1)
|
|
}
|
|
|
|
// Issue 9621
|
|
cmd = exec.Command("go", "run", "-ldflags=-X main.b=false -X main.x=42", "linkx.go")
|
|
outx, err := cmd.CombinedOutput()
|
|
if err == nil {
|
|
fmt.Println("-X linker flag should not overwrite non-strings")
|
|
os.Exit(1)
|
|
}
|
|
outstr := string(outx)
|
|
if !strings.Contains(outstr, "main.b") {
|
|
fmt.Printf("-X linker flag did not diagnose overwrite of main.b:\n%s\n", outstr)
|
|
os.Exit(1)
|
|
}
|
|
if !strings.Contains(outstr, "main.x") {
|
|
fmt.Printf("-X linker flag did not diagnose overwrite of main.x:\n%s\n", outstr)
|
|
os.Exit(1)
|
|
}
|
|
}
|