cmd/link: support -X values for main.* in plugins

crawshaw · crawshaw · commit 273b657b4e97 · 2017-10-04T00:46:06.000Z
Fixes golang#19418 Change-Id: I98205f40c1915cd68a5d20438469ba06f1efb160 Reviewed-on: https://go-review.googlesource.com/67432 Run-TryBot: David Crawshaw <crawshaw@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org>
diff --git a/misc/cgo/testplugin/src/issue19418/main.go b/misc/cgo/testplugin/src/issue19418/main.go
@@ -0,0 +1,29 @@
+// Copyright 2017 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 main
+
+import (
+	"fmt"
+	"os"
+	"plugin"
+)
+
+func main() {
+	p, err := plugin.Open("plugin.so")
+	if err != nil {
+		panic(err)
+	}
+
+	val, err := p.Lookup("Val")
+	if err != nil {
+		panic(err)
+	}
+	got := *val.(*string)
+	const want = "linkstr"
+	if got != want {
+		fmt.Fprintf(os.Stderr, "issue19418 value is %q, want %q\n", got, want)
+		os.Exit(2)
+	}
+}
diff --git a/misc/cgo/testplugin/src/issue19418/plugin.go b/misc/cgo/testplugin/src/issue19418/plugin.go
@@ -0,0 +1,7 @@
+// Copyright 2017 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 main
+
+var Val = "val-unset"
diff --git a/misc/cgo/testplugin/test.bash b/misc/cgo/testplugin/test.bash
@@ -66,3 +66,8 @@ GOPATH=$(pwd) go build -gcflags "$GO_GCFLAGS" -o issue19534 src/issue19534/main.
 GOPATH=$(pwd) go build -gcflags "$GO_GCFLAGS" -buildmode=plugin -o plugin.so src/issue18584/plugin.go
 GOPATH=$(pwd) go build -gcflags "$GO_GCFLAGS" -o issue18584 src/issue18584/main.go
 ./issue18584
+
+# Test for issue 19418
+GOPATH=$(pwd) go build -gcflags "$GO_GCFLAGS" -buildmode=plugin "-ldflags=-X main.Val=linkstr" -o plugin.so src/issue19418/plugin.go
+GOPATH=$(pwd) go build -gcflags "$GO_GCFLAGS" -o issue19418 src/issue19418/main.go
+./issue19418
diff --git a/src/cmd/link/internal/ld/data.go b/src/cmd/link/internal/ld/data.go
@@ -1045,7 +1045,11 @@ func addstrdata1(ctxt *Link, arg string) {
 	if eq < 0 || dot < 0 {
 		Exitf("-X flag requires argument of the form importpath.name=value")
 	}
-	addstrdata(ctxt, objabi.PathToPrefix(arg[:dot])+arg[dot:eq], arg[eq+1:])
+	pkg := objabi.PathToPrefix(arg[:dot])
+	if Buildmode == BuildmodePlugin && pkg == "main" {
+		pkg = *flagPluginPath
+	}
+	addstrdata(ctxt, pkg+arg[dot:eq], arg[eq+1:])
 }
 
 func addstrdata(ctxt *Link, name string, value string) {

Original file line number	Diff line number	Diff line change
`@@ -1045,7 +1045,11 @@ func addstrdata1(ctxt *Link, arg string) {`
`1045`	`1045`	`if eq < 0 \|\| dot < 0 {`
`1046`	`1046`	`Exitf("-X flag requires argument of the form importpath.name=value")`
`1047`	`1047`	`}`
`1048`		`- addstrdata(ctxt, objabi.PathToPrefix(arg[:dot])+arg[dot:eq], arg[eq+1:])`
	`1048`	`+ pkg := objabi.PathToPrefix(arg[:dot])`
	`1049`	`+ if Buildmode == BuildmodePlugin && pkg == "main" {`
	`1050`	`+ pkg = *flagPluginPath`
	`1051`	`+ }`
	`1052`	`+ addstrdata(ctxt, pkg+arg[dot:eq], arg[eq+1:])`
`1049`	`1053`	`}`
`1050`	`1054`
`1051`	`1055`	`func addstrdata(ctxt *Link, name string, value string) {`