Fix debuginfo compression in bootstrap

[Kobzol]

View all comments

Found through https://rust-lang.zulipchat.com/#narrow/channel/326414-t-infra.2Fbootstrap/topic/weird.20code.20in.20fill_target_compiler/with/604588655.

This PR solves a few issues with debuginfo compression in bootstrap.

The main issue was that debuginfo compression through the -gz flag wasn't enabled, by mistake.

When cc-rs checks if a compiler flag is supported, it tries to read out_dir to generate the source file in. However, when this option is not set, then the check silently fails and the flag is considered to be unsupported. Since we didn't set out_dir, all such added flags were simply ignored.

Normally, it reads OUT_DIR, which is fine if cc-rs is used within a build script. But if it is used elsewhere, then this is a pretty gnarly footgun in cc-rs, because the failure is completely silent. CC @madsmtm or @NobodyXu in case you have thoughts on that :)

After that was fixed, I had to change the used compression flag from -gz to --compress-debug-sections, to support both BFD and LLD linkers.

And to solve it properly, and allow dist CI jobs to configure debuginfo compression for all targets that they build, I added a new bootstrap option to configure debuginfo compression.

I wanted the flag to be configurable both globally and per target. At the same time, the flag applies both to C/C++ and Rust. We currently don't have such config area in bootstrap.toml, and [build] didn't seem like the right place, so I shoved it into [rust] (while documenting that it also applies to C/C++).

r? @bjorn3

try-job: dist-x86_64-msvc
try-job: dist-x86_64-apple
try-job: dist-x86_64-linux

[bjorn3]

Thanks!

@bors r+

[rust-bors]

📌 Commit 1bc29dc has been approved by bjorn3

It is now in the queue for this repository.

[rust-bors]

💔 Test for b946733 failed: CI. Failed job:

• auto - x86_64-gnu-distcheck (web logs, enhanced plaintext logs)

[Kobzol]

@bors try jobs=x86_64-gnu-distcheck

[NobodyXu]

Thanks, I've opened an issue #1765, I think this is something we should fix.

We could use a tempfile instead for it

[ChrisDenton]

Thanks, I've opened an issue #1765

I think you meant rust-lang/cc-rs#1765 😉

[rust-bors]

☀️ Try build successful (CI)
Build commit: d269546 (d269546b8320f5f3255b5c7e6268def1a4808374)
Base parent: 4008bbd (4008bbdf34b583ce44a467043aae3703afc0a76f)

[Kobzol]

@bors r=bjorn3

Let's try again.

[rust-bors]

📌 Commit d59253e has been approved by bjorn3

It is now in the queue for this repository.

[rust-bors]

💔 Test for c03a808 failed: CI. Failed job:

• try - dist-x86_64-msvc (web logs, enhanced plaintext logs)

[JonathanBrouwer]

@bors r-

[rust-bors]

This pull request was unapproved.

This PR was contained in a rollup (#158584), which was unapproved.

View changes since this unapproval

[Mark-Simulacrum]

@bors r-

Seems like this grows the command line a bit too long for at least rustc_abi on Windows (I guess we were already very close to the edge).

Not sure what the best solution for that is, maybe we just don't do debuginfo compression on Windows to start? I forget if rustc supports response files, if yes, then we could implement/add support for those in Cargo and/or sccache.

[rust-bors]

This pull request was not previously approved.

[Kobzol]

@bors try

Testing if it also happens without sccache.

[rust-bors]

💔 Test for e103f50 failed: CI. Failed job:

• try - dist-x86_64-msvc (web logs, enhanced plaintext logs)

[Kobzol]

@bors try

[rust-bors]

💔 Test for 4c6d7d3 failed: CI. Failed job:

• try - dist-x86_64-apple (web logs, enhanced plaintext logs)

[Kobzol]

@bors try

[rust-bors]

☀️ Try build successful (CI)
Build commit: 573394b (573394b0c5a21ed70e1369c5784c24b4e7593812)
Base parent: 5165714 (51657149e91586571ff1c463bc58239daa1a88d2)

[Kobzol]

@bors try

[rust-bors]

⌛ Trying commit 9f7569b with merge f2dc3ea…

To cancel the try build, run the command @bors try cancel.

Workflow: https://github.com/rust-lang/rust/actions/runs/28464072089