missing DWARF symbol table

[crazy-max]

Regression from #3320 which always strips DWARF symbol table.

I encounter this issue while trying to debug #3621 but also to improve our shell out operations with debug/buildinfo pkg (available since Go 1.18) for plugins discovery.

Signed-off-by: CrazyMax crazy-max@users.noreply.github.com

[crazy-max]

Ah ok now I remember why we removed DWARF symbol table: https://github.com/docker/cli/runs/7479620604?check_suite_focus=true#step:4:2067

 > [linux/amd64->darwin/arm64 build 3/3] RUN --mount=type=bind,target=.,ro --mount=type=cache,target=/root/.cache --mount=from=dockercore/golang-cross:xx-sdk-extras,target=/xx-sdk,src=/xx-sdk --mount=type=tmpfs,target=cli/winresources xx-go --wrap && TARGET=/out ./scripts/build/binary && xx-verify $([ "static" = "static" ] && echo "--static") /out/docker:
#0 1.584 Building static docker-darwin-arm64
#0 1.603 + go build -o /out/docker-darwin-arm64 -tags osusergo pkcs11 -ldflags -X "github.com/docker/cli/cli/version.GitCommit=f1d40cae1b" -X "github.com/docker/cli/cli/version.BuildTime=2022-07-23T07:51:49Z" -X "github.com/docker/cli/cli/version.Version=22.06.0-beta.0-56-gf1d40cae1b.m" -buildmode=pie github.com/docker/cli/cmd/docker
#67 517.7 # github.com/docker/cli/cmd/docker
#67 517.7 /usr/local/go/pkg/tool/linux_amd64/link: /usr/local/go/pkg/tool/linux_amd64/link: running dsymutil failed: exec: "dsymutil": executable file not found in $PATH
#67 517.7 

By default on Darwin the linker will invoke dsymutil to put the debug info directly into the executable. This invocation of dsymutil is disabled by the linker's -w or -s option 😣

I think our osxsdk used for cross comp darwin binaries might be too old:

cli/Dockerfile

Line 62 in f1615fa

--mount=from=dockercore/golang-cross:xx-sdk-extras,target=/xx-sdk,src=/xx-sdk \

I will take a look

[codecov-commenter]

Codecov Report

Merging #3717 (2854529) into master (f1615fa) will decrease coverage by 0.00%.
The diff coverage is n/a.

@@ Coverage Diff @@## master #3717 +/- ##
==========================================
- Coverage 59.06% 59.06% -0.01% 
==========================================
Files 289 289 Lines 24673 24665 -8 ==========================================
- Hits 14573 14568 -5 + Misses 9226 9224 -2 + Partials 874 873 -1 

[crazy-max]

Ok so we have to install the llvm debian package when using glibc but minimal version required with osxsdk is llvm 12 and bullseye is late: llvm (1:11.0-51+nmu5).

I took a look at https://apt.llvm.org/ but does not seem to include dsymutil 😞:

FROM --platform=$BUILDPLATFORM golang:${GO_VERSION}-bullseye AS build-base-bullseye
COPY --from=xx / /
RUN apt-get update && apt-get install --no-install-recommends -y bash clang lld file lsb-release software-properties-common
RUN wget https://apt.llvm.org/llvm.sh && chmod +x llvm.sh && ./llvm.sh 12 all && rm -f llvm.sh
WORKDIR /go/src/github.com/docker/cli

 > [linux/amd64->darwin/arm64 build 3/3] RUN --mount=type=bind,target=.,ro --mount=type=cache,target=/root/.cache --mount=from=dockercore/golang-cross:xx-sdk-extras,target=/xx-sdk,src=/xx-sdk --mount=type=tmpfs,target=cli/winresources xx-go --wrap && TARGET=/out ./scripts/build/binary && xx-verify $([ "static" = "static" ] && echo "--static") /out/docker:
#0 0.369 Building static docker-darwin-arm64
#0 0.371 + go build -o /out/docker-darwin-arm64 -tags osusergo pkcs11 -ldflags -X "github.com/docker/cli/cli/version.GitCommit=d02816e4fa" -X "github.com/docker/cli/cli/version.BuildTime=2022-07-23T11:44:35Z" -X "github.com/docker/cli/cli/version.Version=22.06.0-beta.0-55-gd02816e4fa.m" -buildmode=pie github.com/docker/cli/cmd/docker
#0 2.803 # github.com/docker/cli/cmd/docker
#0 2.803 /usr/local/go/pkg/tool/linux_amd64/link: /usr/local/go/pkg/tool/linux_amd64/link: running dsymutil failed: exec: "dsymutil": executable file not found in $PATH
#0 2.803

So I think we have to use the osxcross toolchain that includes all the tooling we need. Unfortunately our dockercore/golang-cross:xx-sdk-extras image only includes the osxsdk but I have created an image that includes the osxcross toolchain and the osxsdk: https://github.com/crazy-max/docker-osxcross#usage and everything looks good now using both with alpine and debian.

@tonistiigi Maybe instead of the debian variant we could switch to ubuntu:22.04 that supports llvm 12 and includes dsymutil: https://packages.ubuntu.com/jammy/amd64/llvm-12/filelist but armel cross pkgs are dropped in this release 😣: moby/moby#43529 (comment)

[crazy-max]

@tonistiigi If you're ok with osxcross we could add a detection folder like /xx-sdk on xx so it could set itself the required env vars to use osxcross and we could remove this part in the Dockerfile? Maybe also the ability to support macports like https://github.com/crazy-max/goxx/blob/main/rootfs/usr/local/bin/goxx-macports. WDYT?

[thaJeztah]

By default on Darwin the linker will invoke dsymutil to put the debug info directly into the executable. This invocation of dsymutil is disabled by the linker's -w or -s option

Is this something that could be fixed in Go?

[crazy-max]

@tonistiigi Can't repro everytime but we currently have this issue with BuildKit: https://github.com/docker/cli/runs/7496406536?check_suite_focus=true#step:4:389

#59 [linux/amd64->windows/amd64 build 3/3] RUN --mount=type=bind,target=. --mount=type=cache,target=/root/.cache --mount=from=osxcross,src=/osxcross,target=/osxcross --mount=from=osxcross,src=/osxsdk,target=/xx-sdk --mount=type=tmpfs,target=cli/winresources <<EOT (set -e...)
#59 ERROR: failed to calculate checksum of ref m922mgc9ac45dw652zvglr6tl::w8dtv6wnagnwlcaa7arrzhowq: "/osxsdk": not found

But /osxsdk folder exists for windows/amd64 platform:

$ undock --rm-dist --platform=windows/amd64 crazymax/osxcross:11.3-r7-alpine ./extract
$ tree -nh ./extract
[ 512] ./extract/
├── [ 512] osxcross
└── [ 512] osxsdk
2 directories, 0 files

I wonder is this is not linked to the infamous empty layer issue we had in the past or moby/buildkit#2973.

[crazy-max]

I wonder is this is not linked to the infamous empty layer issue we had in the past or moby/buildkit#2973.

Looking at https://github.com/docker/cli/runs/7497061435?check_suite_focus=true#step:4:330:

#36 [linux/amd64 goversioninfo 1/1] RUN --mount=type=cache,target=/root/.cache/go-build --mount=type=cache,target=/go/pkg/mod GOBIN=/out GO111MODULE=on go install "github.com/josephspurrier/goversioninfo/cmd/goversioninfo@v1.3.0"
#36 CACHED

It seems some instructions are cached even if no cache exporters are in place and the builder is a new one with a fresh BuildKit state in the GHA workflow.

With cache disabled everything looks good: https://github.com/docker/cli/actions/runs/2731390831

[crazy-max]

Ok so after bisect we actually strip DWARF symbol table in 20.10. So not a regression but this is needed for docker-archive/compose-cli#2151. Needs to noop llvm-strip for darwin/amd64 platform with glibc as discussed with @tonistiigi. Can't repro with alpine and LLVM 12.

[crazy-max]

@thaJeztah Comment added. We also discussed with @tonistiigi about this and we could fallback to strip from cctools for dawrin if llvm upstream doesn't work. this could be bundled in xx with ld64 so we could remove this hack.

[thaJeztah]

LGTM

[thaJeztah]

@tonistiigi this LGTY?

[tonistiigi]

We should look more deeply into what that darwin issue is. Is it something broken in old LLVM etc. Is it Debian weirdness? If needed we can get the Apple strip from https://github.com/tpoechtrager/cctools-port/blob/master/cctools/misc/strip.c with ld64 in xx.