llvm-objcopy produces corrupted .debug_str for elf32-x86-64 (X32 ABI) emulation (Z_DATA_ERROR)

[kiroma]

ld.lld: error: arch/x86/entry/vdso/vgetcpu-x32.o:(.debug_str): uncompress failed: zlib error: Z_DATA_ERROR
Tried compiling 5.2-rc4

Clang compiled from the git monorepo, two stage build
clang version 9.0.0 (https://github.com/llvm/llvm-project.git f7ba8b808a89d5e050deb7dbd77004fa8e0dff9b)

[nathanchance]

What is your .config?

[kiroma]

Copied over from OpenSUSE's default config: https://gist.github.com/kiroma/f7766f62f50974db360ac9ffc20ac364
Ran menuconfig once to account for compiler change.

[nathanchance]

I ran:

$ mkdir -p out
$ curl -LSso out/.config https://gist.github.com/kiroma/f7766f62f50974db360ac9ffc20ac364/raw/ea9253d4becc98da16ad7cf4501fb00025d101c8/.config
$ make -j$(nproc) CC=clang LD=ld.lld O=out olddefconfig modules_prepare bzImage modules

and I don't see this error (I see a couple of other ones, namely #327 and ERROR: "__memcat_p" [drivers/hwtracing/stm/stm_core.ko] undefined!, which I'll investigate and open a separate issue for).

What were your LLVM config build options?

[kiroma]

I ran:

make -j$(nproc) CC=clang AS=clang LD=ld.lld AR=llvm-ar NM=llvm-nm STRIP=llvm-strip OBJCOPY=llvm-objcopy OBJDUMP=llvm-objdump HOSTCC=clang HOSTLD=ld.lld HOSTAR=llvm-ar

I configured the build with
-DLLVM_ENABLE_PROJECTS="clang;clang-tools-extra;libunwind;libcxx;libcxxabi;compiler-rt;lld;polly" -DCLANG_DEFAULT_LINKER=lld -DLLVM_ENABLE_LTO=Thin -DLLVM_TARGETS_TO_BUILD=host -DCMAKE_BUILD_TYPE=Release
The first stage was compiled using gcc-9 without LTO.

[nathanchance]

I am going to build with your options to see if I can reproduce it.

In the meantime, would you mind trying out our build script here to see if it still happens there?

[nathanchance]

Alright, this is reproducible using my LLVM toolchain compiled using tc-build and it is related to llvm-objcopy.

$ git clone https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/
$ cd linux
$ git checkout v5.2-rc4
$ mkdir -p out
$ curl -LSso out/.config https://gist.github.com/kiroma/f7766f62f50974db360ac9ffc20ac364/raw/ea9253d4becc98da16ad7cf4501fb00025d101c8/.config

No error:

$ make -j$(nproc) CC=clang LD=ld.lld O=out olddefconfig arch/x86/entry/vdso/

Error:

$ make -j$(nproc) CC=clang LD=ld.lld O=out OBJCOPY=llvm-objcopy olddefconfig arch/x86/entry/vdso/

It looks like the llvm-objcopy call for vgetcpu-x32.o is llvm-objcopy -O elf32-x86-64 arch/x86/entry/vdso/vgetcpu.o arch/x86/entry/vdso/vgetcpu-x32.o according to V=1.

cc @rupprecht

[MaskRay]

Cannot reproduce with https://gist.github.com/kiroma/f7766f62f50974db360ac9ffc20ac364/raw/ea9253d4becc98da16ad7cf4501fb00025d101c8/.config, master or v5.2-rc4: make -j$(nproc) CC=clang LD=ld.lld O=out OBJCOPY=llvm-objcopy olddefconfig arch/x86/entry/vdso/

Can you check your llvm CMakeCache.txt have the following lines?

HAVE_ZLIB_H:INTERNAL=1
LLVM_ENABLE_ZLIB:BOON=ON

[nathanchance]

Yes:

$ fd CMakeCache.txt /mnt/build/llvm -x rg -H -n "HAVE_ZLIB_H|LLVM_ENABLE_ZLIB"
/mnt/build/llvm/stage2/CMakeCache.txt:786:LLVM_ENABLE_ZLIB:BOOL=ON
/mnt/build/llvm/stage2/CMakeCache.txt:1774:HAVE_ZLIB_H:INTERNAL=1
/mnt/build/llvm/stage3/CMakeCache.txt:856:LLVM_ENABLE_ZLIB:BOOL=ON
/mnt/build/llvm/stage3/CMakeCache.txt:2061:HAVE_ZLIB_H:INTERNAL=1
/mnt/build/llvm/stage1/CMakeCache.txt:850:LLVM_ENABLE_ZLIB:BOOL=ON
/mnt/build/llvm/stage1/CMakeCache.txt:2055:HAVE_ZLIB_H:INTERNAL=1

Was that with the .config linked? I can still reproduce this on v5.2-rc6 as of r364149. Could this be a zlib host issue?