Link object files that use #[used]

[DianQK]

By directly linking the object files that use #[used], we ensure the linker can see them.

This approach allows #[used] to avoid modifying symbol visibility, preserving local symbols. A similar example in C would be:

// foo.c
__attribute__((constructor)) static void foo() {}
// main.c
void main(void) {}

If foo.c is placed in a static library, it will never be loaded unless the entire static library is fully loaded by --whole-archive.

This pull request removes some of the symbols in symbols.o. We can remove more symbols in a follow-up PR.

try-job: x86_64-msvc-1
try-job: aarch64-apple

r? bjorn3

[rust-log-analyzer]

The job mingw-check-tidy failed! Check out the build log: (web) (plain)

Click to see the possible cause of the failure (guessed by this bot)

info: removing rustup binaries
info: rustup is uninstalled
##[group]Image checksum input
mingw-check-tidy
# We use the ghcr base image because ghcr doesn't have a rate limit
# and the mingw-check-tidy job doesn't cache docker images in CI.
FROM ghcr.io/rust-lang/ubuntu:22.04
ARG DEBIAN_FRONTEND=noninteractive
RUN apt-get update && apt-get install -y --no-install-recommends \
  g++ \
  make \
---

COPY host-x86_64/mingw-check/validate-toolstate.sh /scripts/
COPY host-x86_64/mingw-check/validate-error-codes.sh /scripts/

# NOTE: intentionally uses python2 for x.py so we can test it still works.
# validate-toolstate only runs in our CI, so it's ok for it to only support python3.
ENV SCRIPT TIDY_PRINT_DIFF=1 python2.7 ../x.py test \
           --stage 0 src/tools/tidy tidyselftest --extra-checks=py,cpp
# This file is autogenerated by pip-compile with Python 3.10
# by the following command:
#
#    pip-compile --allow-unsafe --generate-hashes reuse-requirements.in
---
#12 2.876 Building wheels for collected packages: reuse
#12 2.877   Building wheel for reuse (pyproject.toml): started
#12 3.088   Building wheel for reuse (pyproject.toml): finished with status 'done'
#12 3.089   Created wheel for reuse: filename=reuse-4.0.3-cp310-cp310-manylinux_2_35_x86_64.whl size=132720 sha256=0c2fd2aaf7b0bf8d6e131220aff14712a774c2ca462f3204d25460cbcf610b63
#12 3.090   Stored in directory: /tmp/pip-ephem-wheel-cache-vcokt54a/wheels/3d/8d/0a/e0fc6aba4494b28a967ab5eaf951c121d9c677958714e34532
#12 3.092 Installing collected packages: boolean-py, binaryornot, tomlkit, reuse, python-debian, markupsafe, license-expression, jinja2, chardet, attrs
#12 3.491 Successfully installed attrs-23.2.0 binaryornot-0.4.4 boolean-py-4.0 chardet-5.2.0 jinja2-3.1.4 license-expression-30.3.0 markupsafe-2.1.5 python-debian-0.1.49 reuse-4.0.3 tomlkit-0.13.0
#12 3.491 WARNING: Running pip as the 'root' user can result in broken permissions and conflicting behaviour with the system package manager. It is recommended to use a virtual environment instead: https://pip.pypa.io/warnings/venv
#12 4.032 Collecting virtualenv
#12 4.032 Collecting virtualenv
#12 4.087   Downloading virtualenv-20.29.2-py3-none-any.whl (4.3 MB)
#12 4.241      ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 4.3/4.3 MB 28.2 MB/s eta 0:00:00
#12 4.300 Collecting platformdirs<5,>=3.9.1
#12 4.307   Downloading platformdirs-4.3.6-py3-none-any.whl (18 kB)
#12 4.347 Collecting filelock<4,>=3.12.2
#12 4.377 Collecting distlib<1,>=0.3.7
#12 4.385   Downloading distlib-0.3.9-py2.py3-none-any.whl (468 kB)
#12 4.396      ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 469.0/469.0 KB 49.4 MB/s eta 0:00:00
#12 4.396      ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 469.0/469.0 KB 49.4 MB/s eta 0:00:00
#12 4.475 Installing collected packages: distlib, platformdirs, filelock, virtualenv
#12 4.656 Successfully installed distlib-0.3.9 filelock-3.17.0 platformdirs-4.3.6 virtualenv-20.29.2
#12 DONE 4.7s

#13 [7/8] COPY host-x86_64/mingw-check/validate-toolstate.sh /scripts/
#13 DONE 0.0s
---
DirectMap4k:      128960 kB
DirectMap2M:     5113856 kB
DirectMap1G:    13631488 kB
##[endgroup]
Executing TIDY_PRINT_DIFF=1 python2.7 ../x.py test            --stage 0 src/tools/tidy tidyselftest --extra-checks=py,cpp
+ TIDY_PRINT_DIFF=1 python2.7 ../x.py test --stage 0 src/tools/tidy tidyselftest --extra-checks=py,cpp
    Finished `dev` profile [unoptimized] target(s) in 0.05s
##[endgroup]
WARN: currently no CI rustc builds have rustc debug assertions enabled. Please either set `rust.debug-assertions` to `false` if you want to use download CI rustc or set `rust.download-rustc` to `false`.
downloading https://static.rust-lang.org/dist/2025-02-08/rustfmt-nightly-x86_64-unknown-linux-gnu.tar.xz
---
fmt check
fmt: checked 5853 files
tidy check
tidy: Skipping binary file check, read-only filesystem
##[error]tidy error: /checkout/compiler/rustc_codegen_ssa/src/back/linker.rs:1875: TODO is used for tasks that should be done before merging a PR; If you want to leave a message in the codebase use FIXME
removing old virtual environment
creating virtual environment at '/checkout/obj/build/venv' using 'python3.10' and 'venv'
creating virtual environment at '/checkout/obj/build/venv' using 'python3.10' and 'virtualenv'
Requirement already satisfied: pip in ./build/venv/lib/python3.10/site-packages (25.0.1)
All checks passed!
checking python file formatting
28 files already formatted
checking C++ file formatting
checking C++ file formatting
some tidy checks failed
Command has failed. Rerun with -v to see more details.
  local time: Sat Feb 22 15:52:10 UTC 2025
  network time: Sat, 22 Feb 2025 15:52:10 GMT
##[error]Process completed with exit code 1.
Post job cleanup.

[DianQK]

Weird. The tests failed on macOS after I fixed various test cases. I'll look into it tomorrow.

[bjorn3]

I think we should link all rlibs with --whole-archive. That would also make some currently cgu partitioning dependent linker errors when an unused function references an undefined symbol consistently produce errors independent of which cgu it ends up in.