Description
openedon Oct 26, 2021
I attach a tarball with a small reproducer (few dependencies from crates.io, lock file, empty lib.rs).
Now run this using rustc 1.56.0:
for i in $(seq 1 10); do cargo clean && cargo build --release --quiet && sha256sum target/release/deps/libpalette_derive-*.so; doneI expect the sha256sum to be the same for the libpalette so file but it's often different.
This breaks any binary caches, similarly to what #89904 did but that ticket turned out to be a problem with the crate.
This time it seems problem with rustc itself (or rather LLVM: stay tuned): 1.55.0 produces same binary/crate hash on every build.
Note that in Cargo.toml there's:
[profile.release]
debug = trueWithout this, the issue does not present itself. This perhaps makes it look similar to #89911 or #45397 but I think it's different. As far as I saw, it didn't produce a difference in ordering of symbols in the resulting .so though I may be mistaken. Please feel free to close as duplicate if you deem it to be the same issue.
I have ran with RUSTC_LOG=debug and after careful sifting through few GiB of output, I found the differences seem to start in rustc_codegen_ssa.
I have bisected rustc itself and ran it on our original code which exhibited the problem. I started the bisect at common merge point with 1.55.0 though the problem turned out well into the 1.56.0 release:
$ git bisect good
db002a06ae9154a35d410550bc5132df883d7baa is the first bad commit
commit db002a06ae9154a35d410550bc5132df883d7baa
Merge: e7f7fe462a5 306259c6459
Author: bors <bors@rust-lang.org>
Date: Sat Aug 21 09:25:28 2021 +0000
Auto merge of #87570 - nikic:llvm-13, r=nagisa
Upgrade to LLVM 13
Work in progress update to LLVM 13. Main changes:
* InlineAsm diagnostics reported using SrcMgr diagnostic kind are now handled. Previously these used a separate diag handler.
* Codegen tests are updated for additional attributes.
* Some data layouts have changed.
* Switch `#[used]` attribute from `llvm.used` to `llvm.compiler.used` to avoid SHF_GNU_RETAIN flag introduced in https://reviews.llvm.org/D97448, which appears to trigger a bug in older versions of gold.
* Set `LLVM_INCLUDE_TESTS=OFF` to avoid Python 3.6 requirement.
Upstream issues:
* ~~https://bugs.llvm.org/show_bug.cgi?id=51210 (InlineAsm diagnostic reporting for module asm)~~ Fixed by https://github.com/llvm/llvm-project/commit/1558bb80c01b695ce12642527cbfccf16cf54ece.
* ~~https://bugs.llvm.org/show_bug.cgi?id=51476 (Miscompile on AArch64 due to incorrect comparison elimination)~~ Fixed by https://github.com/llvm/llvm-project/commit/81b106584f2baf33e09be2362c35c1bf2f6bfe94.
* https://bugs.llvm.org/show_bug.cgi?id=51207 (Can't set custom section flags anymore). Problematic change reverted in our fork, https://reviews.llvm.org/D107216 posted for upstream revert.
* https://bugs.llvm.org/show_bug.cgi?id=51211 (Regression in codegen for #83623). This is an optimization regression that we may likely have to eat for this release. The fix for #83623 was based on an incorrect premise, and this needs to be properly addressed in the MergeICmps pass.
The [compile-time impact](https://perf.rust-lang.org/compare.html?start=ef9549b6c0efb7525c9b012148689c8d070f9bc0&end=0983094463497eec22d550dad25576a894687002) is mixed, but quite positive as LLVM upgrades go.
The LLVM 13 final release is scheduled for Sep 21st. The current nightly is scheduled for stable release on Oct 21st.
r? `@ghost`
.gitmodules | 2 +-
compiler/rustc_codegen_llvm/src/back/write.rs | 43 +---------
compiler/rustc_codegen_llvm/src/base.rs | 8 +-
compiler/rustc_codegen_llvm/src/consts.rs | 15 +++-
compiler/rustc_codegen_llvm/src/context.rs | 55 +++++++++----
compiler/rustc_codegen_llvm/src/lib.rs | 2 +-
compiler/rustc_codegen_llvm/src/llvm/diagnostic.rs | 94 +++++++++++++++++-----
compiler/rustc_codegen_llvm/src/llvm/ffi.rs | 7 +-
compiler/rustc_codegen_ssa/src/traits/misc.rs | 2 +
compiler/rustc_codegen_ssa/src/traits/statics.rs | 18 ++---
compiler/rustc_feature/src/accepted.rs | 2 +-
compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp | 20 ++++-
.../src/spec/powerpc64_unknown_linux_gnu.rs | 2 +-
.../src/spec/powerpc64_unknown_linux_musl.rs | 2 +-
.../rustc_target/src/spec/powerpc64_wrs_vxworks.rs | 2 +-
.../src/spec/powerpc64le_unknown_linux_gnu.rs | 2 +-
.../src/spec/powerpc64le_unknown_linux_musl.rs | 2 +-
.../src/spec/wasm32_unknown_emscripten.rs | 2 +-
.../src/spec/wasm32_unknown_unknown.rs | 2 +-
compiler/rustc_target/src/spec/wasm32_wasi.rs | 2 +-
.../src/spec/wasm64_unknown_unknown.rs | 2 +-
src/bootstrap/native.rs | 1 +
src/llvm-project | 2 +-
src/test/codegen/array-equality.rs | 4 +-
src/test/codegen/issue-83623-SIMD-PartialEq.rs | 46 -----------
src/test/codegen/repeat-trusted-len.rs | 2 +-
.../run-make-fulldeps/coverage-llvmir/Makefile | 2 -
.../coverage-llvmir/filecheck.testprog.txt | 18 ++---
src/test/ui/llvm-asm/issue-69092.rs | 4 +-
src/test/ui/llvm-asm/issue-69092.stderr | 4 +-
30 files changed, 201 insertions(+), 168 deletions(-)
delete mode 100644 src/test/codegen/issue-83623-SIMD-PartialEq.rs
cc @nikic who did the update
Meta
rustc --version --verbose:
$ rustc --version --verbose
rustc 1.56.0 (09c42c458 2021-10-18)
binary: rustc
commit-hash: 09c42c45858d5f3aedfa670698275303a3d19afa
commit-date: 2021-10-18
host: x86_64-unknown-linux-gnu
release: 1.56.0
LLVM version: 13.0.0
