cmd/cgo: use --no-gc-sections if available #53028

motiejus · 2022-05-23T08:53:22Z

zig cc passes --gc-sections to the underlying linker, which then
causes undefined symbol errors when compiling with cgo but without C
code. Add -Wl,--no-gc-sections to make it work with zig cc. Minimal
example:

main.go

package main
import _ "runtime/cgo"
func main() {}

Run (works after the patch, doesn't work before):

CC="zig cc" go build main.go

Among the existing code, src/runtime/testdata/testprognet fails to
build:

src/runtime/testdata/testprognet$ CC="zig cc" go build .
net(.text): relocation target __errno_location not defined
net(.text): relocation target getaddrinfo not defined
net(.text): relocation target freeaddrinfo not defined
net(.text): relocation target gai_strerror not defined
runtime/cgo(.text): relocation target stderr not defined
runtime/cgo(.text): relocation target fwrite not defined
runtime/cgo(.text): relocation target vfprintf not defined
runtime/cgo(.text): relocation target fputc not defined
runtime/cgo(.text): relocation target abort not defined
runtime/cgo(.text): relocation target pthread_create not defined
runtime/cgo(.text): relocation target nanosleep not defined
runtime/cgo(.text): relocation target pthread_detach not defined
runtime/cgo(.text): relocation target stderr not defined
runtime/cgo(.text): relocation target strerror not defined
runtime/cgo(.text): relocation target fprintf not defined
runtime/cgo(.text): relocation target abort not defined
runtime/cgo(.text): relocation target pthread_mutex_lock not defined
runtime/cgo(.text): relocation target pthread_cond_wait not defined
runtime/cgo(.text): relocation target pthread_mutex_unlock not defined
runtime/cgo(.text): relocation target pthread_cond_broadcast not defined
runtime/cgo(.text): relocation target malloc not defined

With the patch both examples build as expected.

@ianlancetaylor suggested:

It would be fine with me if somebody wants to send a cgo patch that
passes -Wl,--no-gc-sections, with a fallback if that option is not
supported.

... and this is what we are doing. Tested with zig
0.10.0-dev.2252+a4369918b

This is a continuation of CL 405414: the original one broke AIX and iOS
builds. To fix that, added unknown option to the list of strings
under lookup.

Fixes #52690

gopherbot · 2022-05-23T08:57:44Z

This PR (HEAD: b9ef800) has been imported to Gerrit for code review.

Please visit https://go-review.googlesource.com/c/go/+/407814 to see it.

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gopherbot · 2022-05-23T09:05:16Z

Message from Motiejus Jakštys:

Patch Set 1:

(1 comment)

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gopherbot · 2022-05-23T14:05:00Z

Message from Bryan Mills:

Patch Set 1: Run-TryBot+1 Code-Review+1

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gopherbot · 2022-05-23T14:12:48Z

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Patch Set 1:

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gopherbot · 2022-05-23T14:16:47Z

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Patch Set 1:

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gopherbot · 2022-05-23T14:20:40Z

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Patch Set 1:

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gopherbot · 2022-05-23T14:36:20Z

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Patch Set 1: TryBot-Result-1

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gopherbot · 2022-05-24T00:34:38Z

Message from Ian Lance Taylor:

Patch Set 1:

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gopherbot · 2022-05-24T08:04:22Z

This PR (HEAD: 9e1d5b2) has been imported to Gerrit for code review.

Please visit https://go-review.googlesource.com/c/go/+/407814 to see it.

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gopherbot · 2022-05-24T08:12:07Z

Message from Motiejus Jakštys:

Patch Set 1:

(2 comments)

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gopherbot · 2022-05-24T13:09:03Z

Message from Bryan Mills:

Patch Set 2: Run-TryBot+1 Code-Review+1

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gopherbot · 2022-05-24T13:09:04Z

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Patch Set 2:

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gopherbot · 2022-05-24T13:45:28Z

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Patch Set 2: TryBot-Result+1

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gopherbot · 2022-05-24T15:48:55Z

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Patch Set 2: Code-Review+2

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@ianlancetaylor

zig cc passes `--gc-sections` to the underlying linker, which then causes undefined symbol errors when compiling with cgo but without C code. Add `-Wl,--no-gc-sections` to make it work with zig cc. Minimal example: **main.go** package main import _ "runtime/cgo" func main() {} Run (works after the patch, doesn't work before): CC="zig cc" go build main.go Among the existing code, `src/runtime/testdata/testprognet` fails to build: src/runtime/testdata/testprognet$ CC="zig cc" go build . net(.text): relocation target __errno_location not defined net(.text): relocation target getaddrinfo not defined net(.text): relocation target freeaddrinfo not defined net(.text): relocation target gai_strerror not defined runtime/cgo(.text): relocation target stderr not defined runtime/cgo(.text): relocation target fwrite not defined runtime/cgo(.text): relocation target vfprintf not defined runtime/cgo(.text): relocation target fputc not defined runtime/cgo(.text): relocation target abort not defined runtime/cgo(.text): relocation target pthread_create not defined runtime/cgo(.text): relocation target nanosleep not defined runtime/cgo(.text): relocation target pthread_detach not defined runtime/cgo(.text): relocation target stderr not defined runtime/cgo(.text): relocation target strerror not defined runtime/cgo(.text): relocation target fprintf not defined runtime/cgo(.text): relocation target abort not defined runtime/cgo(.text): relocation target pthread_mutex_lock not defined runtime/cgo(.text): relocation target pthread_cond_wait not defined runtime/cgo(.text): relocation target pthread_mutex_unlock not defined runtime/cgo(.text): relocation target pthread_cond_broadcast not defined runtime/cgo(.text): relocation target malloc not defined With the patch both examples build as expected. @ianlancetaylor suggested: > It would be fine with me if somebody wants to send a cgo patch that passes -Wl,--no-gc-sections, with a fallback if that option is not supported. ... and this is what we are doing. Tested with zig 0.10.0-dev.2252+a4369918b This is a continuation of CL 405414: the original one broke AIX and iOS builds. To fix that, added `unknown option` to the list of strings under lookup. Fixes golang#52690

gopherbot · 2022-05-25T02:55:40Z

This PR (HEAD: 86f227a) has been imported to Gerrit for code review.

Please visit https://go-review.googlesource.com/c/go/+/407814 to see it.

Tip: You can toggle comments from me using the comments slash command (e.g. /comments off)
See the Wiki page for more info

gopherbot · 2022-05-25T02:59:27Z

Message from Motiejus Jakštys:

Patch Set 2:

(1 comment)

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gopherbot · 2022-05-25T23:30:23Z

Message from Ian Lance Taylor:

Patch Set 3: Run-TryBot+1 Auto-Submit+1 Code-Review+1

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gopherbot · 2022-05-25T23:34:21Z

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Patch Set 3:

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gopherbot · 2022-05-25T23:42:05Z

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Patch Set 3:

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gopherbot · 2022-05-26T00:15:58Z

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Patch Set 3: TryBot-Result-1

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@ianlancetaylor

zig cc passes `--gc-sections` to the underlying linker, which then causes undefined symbol errors when compiling with cgo but without C code. Add `-Wl,--no-gc-sections` to make it work with zig cc. Minimal example: **main.go** package main import _ "runtime/cgo" func main() {} Run (works after the patch, doesn't work before): CC="zig cc" go build main.go Among the existing code, `src/runtime/testdata/testprognet` fails to build: src/runtime/testdata/testprognet$ CC="zig cc" go build . net(.text): relocation target __errno_location not defined net(.text): relocation target getaddrinfo not defined net(.text): relocation target freeaddrinfo not defined net(.text): relocation target gai_strerror not defined runtime/cgo(.text): relocation target stderr not defined runtime/cgo(.text): relocation target fwrite not defined runtime/cgo(.text): relocation target vfprintf not defined runtime/cgo(.text): relocation target fputc not defined runtime/cgo(.text): relocation target abort not defined runtime/cgo(.text): relocation target pthread_create not defined runtime/cgo(.text): relocation target nanosleep not defined runtime/cgo(.text): relocation target pthread_detach not defined runtime/cgo(.text): relocation target stderr not defined runtime/cgo(.text): relocation target strerror not defined runtime/cgo(.text): relocation target fprintf not defined runtime/cgo(.text): relocation target abort not defined runtime/cgo(.text): relocation target pthread_mutex_lock not defined runtime/cgo(.text): relocation target pthread_cond_wait not defined runtime/cgo(.text): relocation target pthread_mutex_unlock not defined runtime/cgo(.text): relocation target pthread_cond_broadcast not defined runtime/cgo(.text): relocation target malloc not defined With the patch both examples build as expected. @ianlancetaylor suggested: > It would be fine with me if somebody wants to send a cgo patch that passes -Wl,--no-gc-sections, with a fallback if that option is not supported. ... and this is what we are doing. Tested with zig 0.10.0-dev.2252+a4369918b This is a continuation of CL 405414: the original one broke AIX and iOS builds. To fix that, added `unknown option` to the list of strings under lookup. Fixes #52690 Change-Id: Id6743e1e759a02627b0fc6d2ac89bb69b706d04c GitHub-Last-Rev: 86f227a GitHub-Pull-Request: #53028 Reviewed-on: https://go-review.googlesource.com/c/go/+/407814 Reviewed-by: Cherry Mui <cherryyz@google.com> Auto-Submit: Ian Lance Taylor <iant@google.com> Reviewed-by: Bryan Mills <bcmills@google.com> Reviewed-by: Ian Lance Taylor <iant@google.com> Run-TryBot: Ian Lance Taylor <iant@google.com>

gopherbot · 2022-05-26T00:53:13Z

This PR is being closed because golang.org/cl/407814 has been merged.

motiejus force-pushed the no-gc-sections-2 branch from b9ef800 to 9e1d5b2 Compare May 24, 2022 08:02

motiejus force-pushed the no-gc-sections-2 branch from 9e1d5b2 to 86f227a Compare May 25, 2022 02:54

gopherbot closed this May 26, 2022

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cmd/cgo: use --no-gc-sections if available #53028

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cmd/cgo: use --no-gc-sections if available #53028

cmd/cgo: use --no-gc-sections if available #53028

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