[go] cmd/go: -ldflags=-linkmode=external requires runtime/cgo
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Ian Lance Taylor (Gerrit)
Nov 10, 2016, 1:02:26 PM11/10/16
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Ian Lance Taylor uploaded cmd/go: -ldflags=-linkmode=external requires runtime/cgo for review.
cmd/go: -ldflags=-linkmode=external requires runtime/cgo We add runtime/cgo to the list of import paths for various cases that imply external linking mode, but before this change we did not add for an explicit request of external linking mode. This fixes the case where you are using a non-default buildmode that implies a different compilation option (for example, -buildmode=pie implies -shared) and the runtime/cgo package for that option is stale. No test, as I'm not sure how to write one. It would require forcing a stale runtime/cgo. Change-Id: Id0409c7274ce67fe15d910baf587d3220cb53d83 --- M src/cmd/go/pkg.go 1 file changed, 12 insertions(+), 3 deletions(-)
diff --git a/src/cmd/go/pkg.go b/src/cmd/go/pkg.go
index 079412c..0c251dd 100644
--- a/src/cmd/go/pkg.go
+++ b/src/cmd/go/pkg.go
@@ -914,10 +914,19 @@
}
// Currently build modes c-shared, pie, plugin, and -linkshared force
- // external linking mode, and external linking mode forces an
- // import of runtime/cgo.
+ // external linking mode, as of course does -ldflags=-linkmode=external,
+ // and external linking mode forces an import of runtime/cgo.
pieCgo := buildBuildmode == "pie" && (buildContext.GOOS != "linux" || buildContext.GOARCH != "amd64")
- if p.Name == "main" && !p.Goroot && (buildBuildmode == "c-shared" || buildBuildmode == "plugin" || pieCgo || buildLinkshared) {
+ linkmodeExternal := false
+ for i, a := range buildLdflags {
+ if a == "-linkmode=external" {
+ linkmodeExternal = true
+ }
+ if a == "-linkmode" && i+1 < len(buildLdflags) && buildLdflags[i+1] == "external" {
+ linkmodeExternal = true
+ }
+ }
+ if p.Name == "main" && !p.Goroot && (buildBuildmode == "c-shared" || buildBuildmode == "plugin" || pieCgo || buildLinkshared || linkmodeExternal) {
importPaths = append(importPaths, "runtime/cgo")
}
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Gobot Gobot (Gerrit)
Nov 10, 2016, 1:03:13 PM11/10/16
to Ian Lance Taylor, golang-co...@googlegroups.com
Gobot Gobot posted comments on cmd/go: -ldflags=-linkmode=external requires runtime/cgo.
Patch Set 1:
TryBots beginning. Status page: http://farmer.golang.org/try?commit=4dbee27f
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Gobot Gobot (Gerrit)
Nov 10, 2016, 1:08:52 PM11/10/16
to Ian Lance Taylor, golang-co...@googlegroups.com
Gobot Gobot posted comments on cmd/go: -ldflags=-linkmode=external requires runtime/cgo.
Patch Set 1: TryBot-Result+1
TryBots are happy.
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Michael Hudson-Doyle (Gerrit)
Nov 10, 2016, 1:22:05 PM11/10/16
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Michael Hudson-Doyle posted comments on cmd/go: -ldflags=-linkmode=external requires runtime/cgo.
Patch Set 1: Code-Review+2
(1 comment)
It feels a bit unpleasant to have to duplicate this information between here and the linker, but that's not what this change is about.
I guess you could change this to "pie (except on linux/amd64)"? Or maybe change the comment to be less of a hostage to the future.
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Ian Lance Taylor (Gerrit)
Nov 10, 2016, 1:45:35 PM11/10/16
to Michael Hudson-Doyle, Gobot Gobot, golang-co...@googlegroups.com
Ian Lance Taylor uploaded patch set #2 to cmd/go: -ldflags=-linkmode=external requires runtime/cgo.
cmd/go: -ldflags=-linkmode=external requires runtime/cgo We add runtime/cgo to the list of import paths for various cases that imply external linking mode, but before this change we did not add for an explicit request of external linking mode. This fixes the case where you are using a non-default buildmode that implies a different compilation option (for example, -buildmode=pie implies -shared) and the runtime/cgo package for that option is stale. No test, as I'm not sure how to write one. It would require forcing a stale runtime/cgo. Change-Id: Id0409c7274ce67fe15d910baf587d3220cb53d83 --- M src/cmd/go/pkg.go 1 file changed, 15 insertions(+), 4 deletions(-)
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Ian Lance Taylor (Gerrit)
Nov 10, 2016, 1:45:45 PM11/10/16
to Michael Hudson-Doyle, Gobot Gobot, golang-co...@googlegroups.com
Ian Lance Taylor posted comments on cmd/go: -ldflags=-linkmode=external requires runtime/cgo.
Patch Set 2:
(1 comment)
Patch Set #1, Line 916:
// Currently build modes c-shared, pie (on systems that do not
I guess you could change this to "pie (except on linux/amd64)"? Or maybe ch
Done
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Ian Lance Taylor (Gerrit)
Nov 10, 2016, 1:46:04 PM11/10/16
to golang-...@googlegroups.com, Michael Hudson-Doyle, Gobot Gobot, golang-co...@googlegroups.com
Ian Lance Taylor merged cmd/go: -ldflags=-linkmode=external requires runtime/cgo.
cmd/go: -ldflags=-linkmode=external requires runtime/cgo We add runtime/cgo to the list of import paths for various cases that imply external linking mode, but before this change we did not add for an explicit request of external linking mode. This fixes the case where you are using a non-default buildmode that implies a different compilation option (for example, -buildmode=pie implies -shared) and the runtime/cgo package for that option is stale. No test, as I'm not sure how to write one. It would require forcing a stale runtime/cgo. Change-Id: Id0409c7274ce67fe15d910baf587d3220cb53d83 Reviewed-on: https://go-review.googlesource.com/33070 Reviewed-by: Michael Hudson-Doyle <michael...@canonical.com> --- M src/cmd/go/pkg.go 1 file changed, 15 insertions(+), 4 deletions(-)
Approvals: Michael Hudson-Doyle: Looks good to me, approved
diff --git a/src/cmd/go/pkg.go b/src/cmd/go/pkg.go
index 079412c..23d3114 100644
--- a/src/cmd/go/pkg.go
+++ b/src/cmd/go/pkg.go
@@ -913,11 +913,22 @@
importPaths = append(importPaths, "syscall")
}
- // Currently build modes c-shared, pie, plugin, and -linkshared force
- // external linking mode, and external linking mode forces an
- // import of runtime/cgo.
+ // Currently build modes c-shared, pie (on systems that do not
+ // support PIE with internal linking mode), plugin, and
+ // -linkshared force external linking mode, as of course does
+ // -ldflags=-linkmode=external. External linking mode forces
+ // an import of runtime/cgo.
pieCgo := buildBuildmode == "pie" && (buildContext.GOOS != "linux" || buildContext.GOARCH != "amd64")
- if p.Name == "main" && !p.Goroot && (buildBuildmode == "c-shared" || buildBuildmode == "plugin" || pieCgo || buildLinkshared) {
+ linkmodeExternal := false
+ for i, a := range buildLdflags {
+ if a == "-linkmode=external" {
+ linkmodeExternal = true
+ }
+ if a == "-linkmode" && i+1 < len(buildLdflags) && buildLdflags[i+1] == "external" {
+ linkmodeExternal = true
+ }
+ }
+ if p.Name == "main" && !p.Goroot && (buildBuildmode == "c-shared" || buildBuildmode == "plugin" || pieCgo || buildLinkshared || linkmodeExternal) {
importPaths = append(importPaths, "runtime/cgo")
}
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Brad Fitzpatrick (Gerrit)
Nov 10, 2016, 5:55:36 PM11/10/16
to Ian Lance Taylor, Michael Hudson-Doyle, Gobot Gobot, golang-co...@googlegroups.com, Brad Fitzpatrick
Brad Fitzpatrick posted comments on cmd/go: -ldflags=-linkmode=external requires runtime/cgo.
Patch Set 3:
This CL broke the nocgo build.
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Ian Lance Taylor (Gerrit)
Nov 10, 2016, 6:20:33 PM11/10/16
to Michael Hudson-Doyle, Gobot Gobot, golang-co...@googlegroups.com
Ian Lance Taylor posted comments on cmd/go: -ldflags=-linkmode=external requires runtime/cgo.
Patch Set 3:
> This CL broke the nocgo build.
Whoops. The code was already broken in some cases, but this broke it more.
https://golang.org/cl/33104
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