GNU linker warns “corrupt .drectve” on staticlib binary generated with Rust 1.70 on Windows

It seems, as of version 16, LLVM generates a binary containing incompatible directive with GNU linker. I believe this is the cause:

commit: llvm/llvm-project@c5b3de6

Since Rust 1.70 upgraded LLVM to version 16, we started to see a lot of warnings by GNU linker when I link against staticlibs compiled by Rust. The warnings are like this:

Warning: .drectve `-exclude-symbols:_ZN7testpkg11hello_world17ha68eef8a416aa303E ' unrecognized
Warning: corrupt .drectve at end of def file

It seems I can just ignore this warning (while the concern described in the LLVM's commit can be a real problem in future), but still I feel this is something that should be fixed if possible. I know, from LLVM's viewpoint, it's reasonable to assume the linker is lld and embed the directives that only lld can understand. But, on the other hand, from Rust's viewpoint, is it intentional that the "GNU" target produces a binary that is incompatible with "GNU" linker? I'm honestly not sure about the answer. I'm yet to figure out what the "GNU" in Rust's GNU toolchain/target actually means.

Code

A minimal reproducible code: https://github.com/yutannihilation/rust170_gnu_warning

# compile Rust code to create a staticlib
cargo build --target=x86_64-pc-windows-gnu --lib --release

# compile the C code
gcc -c main.c -o main.o

# link to the staticlib
gcc -o testpkgrust170_gnu_warning.dll main.o -L./target/x86_64-pc-windows-gnu/release -lrust170_gnu_warning -lws2_32 -ladvapi32 -luserenv -lbcrypt -lntdll

In case of Rust 1.69, we don't see any warnings. However, if it's compiled using Rust 1.70, GNU linker warns:

Warning: corrupt .drectve at end of def file
Warning: corrupt .drectve at end of def file

(This can be reproducible on GHA: result)

Version it worked on

It most recently worked on: Rust 1.69

Version with regression

rustc --version --verbose:

rustc 1.70.0 (90c541806 2023-05-31)
binary: rustc
commit-hash: 90c541806f23a127002de5b4038be731ba1458ca
commit-date: 2023-05-31
host: x86_64-pc-windows-msvc
release: 1.70.0
LLVM version: 16.0.2

Backtrace

References

the original context: Fix compile error on Windows with Rust 1.70 extendr/rextendr#285 (comment)
post on the Rust user forum before reporting here: https://users.rust-lang.org/t/corrupt-drectve-warning-on-x86-64-pc-windows-gnu-target-with-rust-1-70/94912

Looks like support for the -exclude-symbols .drectve was added to GNU ld in this commit, and then added to lld in these two commits.

Those changes were released in Binutils 2.40 (the latest) and LLVM 15, both fairly new versions. GNU ld < 2.40 will emit a warning if it sees this directive, and lld < 15 will fail to link.

Thank you so much! It really helps.

In our particular use case, we use a toolchain called Rtools, which is provided for compiling R packages, and, fortunately, the latest version of it uses binutils 2.40.

These packages have been updated:

(...snip...)
binutils 2.39 to 2.40
(https://cran.r-project.org/bin/windows/Rtools/rtools43/news.html)

Actually, I confirmed I don't see these warnings after I updated the toolchain to the latest version (I didn't notice there's a newer version). So, this might be a less serious problem than I thought at first. I'm not sure if it's fine in general to require such a new version of binutils, though.

@rustbot

@rustbot label -regression-untriaged +regression-from-stable-to-stable

FWIW, I'm running into this issue with lld 14 and I'm definitely not a good position to trivially upgrade to lld 15+ (though I guess if I stick with 1.69.0 for another year or so the maintainers of my toolchain packages will manage to release one based on lld 15).

I'm using the GNU LD linker for two reasons:

Because the normal linker hangs 9/10 times - See Linker hangs with no output 9/10 times. #88704
Because the normal linker doesn't have the ability to do some things in the way I want for embedded development, so I use arm-none-eabi-ld.

I too started seeing the warnings detailed above after upgrading the nightly version of rust I'm using.

Example warnings from gnu ld 2.34. (arm-none-eabi) and gnu ld 2.39.

Warning: .drectve `-exclude-symbols:"_ZN77_$LT$alloc..raw_vec..RawVec$LT$T$C$A$GT$$u20$as$u20$core..ops..drop..Drop$GT$4drop17hb89ba7c74cb66113E" ' unrecognized
Warning: .drectve `-exclude-symbols:"_ZN5alloc7raw_vec19RawVec$LT$T$C$A$GT$7reserve21do_reserve_and_handle17heb762ccf93d8463bE" ' unrecognized
Warning: corrupt .drectve at end of def file

At the time of writing the latest official GNU Arm Tools is 12.2.MPACBTI-Rel1 https://developer.arm.com/downloads/-/arm-gnu-toolchain-downloads which give you this version:

GNU ld (Arm GNU Toolchain 12.2.MPACBTI-Rel1 (Build arm-12-mpacbti.34)) 2.40.0.20230307

which is 2.40.

However, I still see all the warnings, as follows:

Warning: .drectve `-exclude-symbols:"_ZN77_$LT$alloc..raw_vec..RawVec$LT$T$C$A$GT$$u20$as$u20$core..ops..drop..Drop$GT$4drop17hb89ba7c74cb66113E" ' unrecognized
Warning: .drectve `-exclude-symbols:"_ZN5alloc7raw_vec19RawVec$LT$T$C$A$GT$7reserve21do_reserve_and_handle17heb762ccf93d8463bE" ' unrecognized
Warning: corrupt .drectve at end of def file

It's thus not correct to say that "GNU < 2.40" (see #112368 (comment)) will emit warnings, as 2.40.20230307 certainly still emits them.

I guess I'll have to wait for a new GNU Arm Tools release or build windows binaries somehow, neither of which are appealing. 😄

But, on the other hand, from Rust's viewpoint, is it intentional that the "GNU" target produces a binary that is incompatible with "GNU" linker? I'm honestly not sure about the answer. I'm yet to figure out what the "GNU" in Rust's GNU toolchain/target actually means.

When you use a -gnu target, that is effectively meant to be, for most intents and purposes, "compatible with glibc". I have not really heard Rust team members discuss them in other terms. Obviously, there are some caveats here about dynamic loaders, but that isn't necessarily the same as the static linker.

It seems I can just ignore this warning (while the concern described in the LLVM's commit can be a real problem in future), but still I feel this is something that should be fixed if possible. I know, from LLVM's viewpoint, it's reasonable to assume the linker is lld and embed the directives that only lld can understand. But, on the other hand, from Rust's viewpoint, is it intentional that the "GNU" target produces a binary that is incompatible with "GNU" linker? I'm honestly not sure about the answer.

It's harmless warning. Previously binaries would contain unnecessary symbols and this newly introduced feature gets rid of them. Like already said here it's supported by GNU toolchain (since Binutils 2.40)

I'm yet to figure out what the "GNU" in Rust's GNU toolchain/target actually means.

Most importantly artifacts produced by Rust and GNU toolchain (GCC+Binutils+mingw-w64) are compatible with each other. Linking and the resulting binaries still work but a warning is shown when Binutils are too old to support feature used by LLVM. Surely this is not ideal (maybe there is a way to silence this warning from ld.bfd?) but I don't believe they are incompatible.

It's thus not correct to say that "GNU < 2.40" (see #112368 (comment)) will emit warnings, as 2.40.20230307 certainly still emits them.

2.40 does contain the required changes, either you have some environment issue or their version is not 2.40.
Using 2.40 Binutils from MSYS2:

$ rustc -vV
rustc 1.70.0 (90c541806 2023-05-31)
binary: rustc
commit-hash: 90c541806f23a127002de5b4038be731ba1458ca
commit-date: 2023-05-31
host: x86_64-pc-windows-gnu
release: 1.70.0
LLVM version: 16.0.2

$ cargo b --lib -r
   Compiling rust170_gnu_warning v0.1.0 (D:\tmp\rust170_gnu_warning)
    Finished release [optimized] target(s) in 0.51s

$ gcc -c main.c -o main.o

$ gcc -o testpkgrust170_gnu_warning.dll main.o -L./target/release -lrust170_gnu_warning -lws2_32 -ladvapi32 -luserenv -lbcrypt -lntdll

$ ld --version
GNU ld (GNU Binutils) 2.40
Copyright (C) 2023 Free Software Foundation, Inc.
This program is free software; you may redistribute it under the terms of
the GNU General Public License version 3 or (at your option) a later version.
This program has absolutely no warranty.

$ gcc --version
gcc.exe (Rev7, Built by MSYS2 project) 13.1.0
Copyright (C) 2023 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

When you use a -gnu target, that is effectively meant to be, for most intents and purposes, "compatible with glibc". I have not really heard people discuss them in other terms.

When speaking of windows-gnu target it's never about glibc but a GNU toolchain so GCC and Binutils (or compatible one like LLVM) coupled with MinGW.

Thanks for the detailed explaination!

Surely this is not ideal (maybe there is a way to silence this warning from ld.bfd?) but I don't believe they are incompatible.

I now agree with you.

Since my problem is almost solved, I'm fine to close this issue. The only two reasons I keep this open are (1) I don't have enough knowledge to judge if this is a negligible issue (2) those who suffer from this warning might find this easier. Should I close this issue?

Regarding #112368 (comment), I also confirmed 2.40 contains the required change. So, it seems it's a problem on Arm's GCC toolchain's side, not on Rust's side.

@mati865

@mati865 Thanks, but I didn't have any fixes in mind, so I simply removed the gnu target. This issue came up after the 1.70 release, but I can't reproduce it locally.

You probably have a different Binutils version locally and it doesn't crash.
Rust upgrade is not very relevant, Rust output has changed a bit in a way that causes this crash but a similar crash could also happen when you modify your code in a specific way.

For binutils I have 2.42 locally, and https://github.com/actions/runner-images/blob/main/images/windows/Windows2022-Readme.md shows the CI have the binutils 2.39. I'll continue to delve into this when I can.

rust won't pick locally installed binutils automatically because auto detection code there can detect only one special distribution and that distribution ships outdated binutils.

niXman/mingw-builds-binaries#68

Rust will pick any linker from the PATH that is named <arch>-w64-mingw32-gcc so it's compatible with most, if not all distributions.

Auto merge of rust-lang#119229 - mati865:update-mingw-toolchain, r=<try>

Rollup merge of rust-lang#119229 - mati865:update-mingw-toolchain, r=…

Unrolled build for rust-lang#119229

Rollup merge of #119229 - mati865:update-mingw-toolchain, r=jieyouxu,…

Navigation Menu

Repository navigation

GNU linker warns “corrupt .drectve” on staticlib binary generated with Rust 1.70 on Windows #112368

Code

Version it worked on

Version with regression

Backtrace

References

27 remaining items

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

GNU linker warns “corrupt .drectve” on staticlib binary generated with Rust 1.70 on Windows #112368

Description

Code

Version it worked on

Version with regression

Backtrace

References

Activity

erikdesjardins commented on Jun 8, 2023

yutannihilation commented on Jun 8, 2023

Jules-Bertholet commented on Jun 10, 2023

saurik commented on Jun 13, 2023

hydra commented on Jun 15, 2023

workingjubilee commented on Jun 23, 2023

mati865 commented on Jun 24, 2023

yutannihilation commented on Jun 24, 2023

27 remaining items

Zxilly commented on Jul 29, 2024

mati865 commented on Jul 29, 2024

Zxilly commented on Jul 29, 2024

hsn10 commented on Jul 29, 2024

mati865 commented on Jul 29, 2024

Metadata

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

Issue actions