linux split-dwarf fails with `-Clinker-plugin-lto`

[vlovich]

When I add split-debuginfo = "unpacked" to my profile.release in Cargo.toml (on Linux), my build fails with:

error: failed to build archive: No such file or directory

error: could not compile `cfg-if` due to previous error
warning: build failed, waiting for other jobs to finish...

In debug I initially had the same problem but a cargo clean fixed it without requiring me to turn off split-debuginfo. However, release continues to be failing even after cargo clean.

Meta

rustc --version
rustc 1.65.0 (897e375 2022-11-02)
cargo --version
cargo 1.65.0 (4bc8f24d3 2022-10-20)

[davidli2010]

It's silent in my macOS in release profile, but no dSYM generated. It's OK in dev profile.

[vlovich]

Oh not sure if it matters, but I also have debug = true set for my release build.

[davidli2010]

Thanks for your reminder. I forgot that debug is off by default in release profile.

[ItsEthra]

Can confirm this happens for me as well but with split-debuginfo=packed.

error: failed to build archive: No such file or directory

error: could not compile `static_assertions` due to previous error
warning: build failed, waiting for other jobs to finish...
error: could not compile `lazy_static` due to previous error

rustc 1.65.0 (897e37553 2022-11-02)
cargo 1.65.0 (4bc8f24d3 2022-10-20

[ehuss]

Can you provide some more information, such as the target you are building for (x86_64-unknown-linux-gnu?), the output of rustc --version --verbose, and anything else that might help narrow down the issue? Is your profile exactly this?

[profile.release]
split-debuginfo = "unpacked"
debug = true

[filialpails]

I got this same error when I tried compiling with both split debug info and linker plugin LTO.

[tchollingsworth]

also need LTO enabled, works fine without here

% cargo new repro
% cd repro
% cat <<EOF >> Cargo.toml
log = "0.4.17"

[profile.release]
lto = true # or "thin"
debug = true
split-debuginfo = "unpacked" # or "packed"
EOF
% cargo build --release --verbose
   Compiling log v0.4.17
   Compiling cfg-if v1.0.0
     Running `rustc --crate-name build_script_build /home/tc/.cargo/registry/src/6github.com-1ecc6299db9ec823/log-0.4.17/build.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --crate-type bin --emit=dep-info,link -C embed-bitcode=no -C split-debuginfo=packed -C debuginfo=2 -C debug-assertions=off -C metadata=3d94976ee9c5caca -C extra-filename=-3d94976ee9c5caca --out-dir /home/tc/dev/repro/target/release/build/log-3d94976ee9c5caca -L dependency=/home/tc/dev/repro/target/release/deps --cap-lints allow`
     Running `rustc --crate-name cfg_if --edition=2018 /home/tc/.cargo/registry/src/6github.com-1ecc6299db9ec823/cfg-if-1.0.0/src/lib.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --crate-type lib --emit=dep-info,metadata,link -C opt-level=3 -C linker-plugin-lto -C split-debuginfo=packed -C debuginfo=2 -C metadata=9e1e3997dce77d3a -C extra-filename=-9e1e3997dce77d3a --out-dir /home/tc/dev/repro/target/release/deps -L dependency=/home/tc/dev/repro/target/release/deps --cap-lints allow`
error: failed to build archive: No such file or directory

error: could not compile `cfg-if` due to previous error

Caused by:
  process didn't exit successfully: `rustc --crate-name cfg_if --edition=2018 /home/tc/.cargo/registry/src/6github.com-1ecc6299db9ec823/cfg-if-1.0.0/src/lib.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --crate-type lib --emit=dep-info,metadata,link -C opt-level=3 -C linker-plugin-lto -C split-debuginfo=packed -C debuginfo=2 -C metadata=9e1e3997dce77d3a -C extra-filename=-9e1e3997dce77d3a --out-dir /home/tc/dev/repro/target/release/deps -L dependency=/home/tc/dev/repro/target/release/deps --cap-lints allow` (exit status: 1)
warning: build failed, waiting for other jobs to finish...
% rustc --version --verbose
rustc 1.65.0 (897e37553 2022-11-02)
binary: rustc
commit-hash: 897e37553bba8b42751c67658967889d11ecd120
commit-date: 2022-11-02
host: x86_64-unknown-linux-gnu
release: 1.65.0
LLVM version: 15.0.0
% rustup show
Default host: x86_64-unknown-linux-gnu
rustup home:  /home/tc/.rustup

stable-x86_64-unknown-linux-gnu (default)
rustc 1.65.0 (897e37553 2022-11-02)

[vlovich]

Thanks @tchollingsworth for clarifying. Yeah, I do have LTO on as well.

[ehuss]

cc @davidtwco or @michaelwoerister in case this didn't hit your radar.

The reproduction is:

touch foo.rs
rustc --crate-type=rlib -Csplit-debuginfo=packed -Clinker-plugin-lto foo.rs

with the error:

error: failed to build archive: No such file or directory

error: aborting due to previous error

From what I can tell, the archiver is expecting a .dwo file to exist (added around here). AFAIK, that doesn't make sense with a bitcode-only output. The decision of whether or not a dwo is expected I think is made around here. I'm guessing that decision (or perhaps something at a higher level) needs to be aware that the split-dwarf won't happen with bitcode-only output? (IOW, that case should only be true if write_output_file was called with a dwo_out value with Some?)

[marmeladema]

Should this issue be marked as a stable-to-stable regression?