llvm dev - Oct 2020 - compiler-rt linking failure on linux-sparcv9

Hi!

The build on linux-sparcv9 has recently started to fail with a linker failure
that looks easy to
fix but so far I've been unable to find out where to include the necessary
-latomic [1]:

/usr/bin/ld: warning: -z gnu-version-script-compat ignored
/usr/bin/ld:
projects/compiler-rt/lib/asan/CMakeFiles/RTAsan_dynamic.sparc.dir/asan_allocator.cpp.o:
in function `__sanitizer::atomic_uint64_t::Type
__sanitizer::atomic_load<__sanitizer::atomic_uint64_t>(__sanitizer::atomic_uint64_t
const volatile*, __sanitizer::memory_order)':
/home/glaubitz/llvm-project/compiler-rt/lib/asan/../sanitizer_common/sanitizer_atomic_clang_other.h:56:
undefined reference to `__sync_fetch_and_add_8'
/usr/bin/ld:
/home/glaubitz/llvm-project/compiler-rt/lib/asan/../sanitizer_common/sanitizer_atomic_clang_other.h:56:
undefined reference to `__sync_fetch_and_add_8'
/usr/bin/ld:
/home/glaubitz/llvm-project/compiler-rt/lib/asan/../sanitizer_common/sanitizer_atomic_clang_other.h:56:
undefined reference to `__sync_fetch_and_add_8'
/usr/bin/ld:
/home/glaubitz/llvm-project/compiler-rt/lib/asan/../sanitizer_common/sanitizer_atomic_clang_other.h:56:
undefined reference to `__sync_fetch_and_add_8'
/usr/bin/ld:
/home/glaubitz/llvm-project/compiler-rt/lib/asan/../sanitizer_common/sanitizer_atomic_clang_other.h:56:
undefined reference to `__sync_fetch_and_add_8'
/usr/bin/ld:
projects/compiler-rt/lib/asan/CMakeFiles/RTAsan_dynamic.sparc.dir/asan_allocator.cpp.o:/home/glaubitz/llvm-project/compiler-rt/lib/asan/../sanitizer_common/sanitizer_atomic_clang_other.h:56:
more undefined references to `__sync_fetch_and_add_8' follow
/usr/bin/ld:
projects/compiler-rt/lib/asan/CMakeFiles/RTAsan_dynamic.sparc.dir/asan_allocator.cpp.o:
in function `void
__sanitizer::atomic_store<__sanitizer::atomic_uint64_t>(__sanitizer::atomic_uint64_t
volatile*, __sanitizer::atomic_uint64_t::Type, __sanitizer::memory_order)':
/home/glaubitz/llvm-project/compiler-rt/lib/asan/../sanitizer_common/sanitizer_atomic_clang_other.h:87:
undefined reference to `__sync_val_compare_and_swap_8'
/usr/bin/ld:
/home/glaubitz/llvm-project/compiler-rt/lib/asan/../sanitizer_common/sanitizer_atomic_clang_other.h:87:
undefined reference to `__sync_val_compare_and_swap_8'
/usr/bin/ld:
/home/glaubitz/llvm-project/compiler-rt/lib/asan/../sanitizer_common/sanitizer_atomic_clang_other.h:87:
undefined reference to `__sync_val_compare_and_swap_8'
/usr/bin/ld:
/home/glaubitz/llvm-project/compiler-rt/lib/asan/../sanitizer_common/sanitizer_atomic_clang_other.h:87:
undefined reference to `__sync_val_compare_and_swap_8'
collect2: error: ld returned 1 exit status
ninja: build stopped: subcommand failed.

Does anyone have any suggestion where to add the necessary linker flags?

Full build log in [1].

Adrian
> [1]
https://buildd.debian.org/status/fetch.php?pkg=llvm-toolchain-snapshot&arch=sparc64&ver=1%3A12%7E%2B%2B20200929085817%2B962a247aebb-1%7Eexp1&stamp=1603274506&raw=0
-- 
 .''`.  John Paul Adrian Glaubitz
: :' :  Debian Developer - glaubitz at debian.org
`. `'   Freie Universitaet Berlin - glaubitz at physik.fu-berlin.de
  `-    GPG: 62FF 8A75 84E0 2956 9546  0006 7426 3B37 F5B5 F913

Hello!

On 10/21/20 8:19 PM, John Paul Adrian Glaubitz wrote:
> The build on linux-sparcv9 has recently started to fail with a linker
failure that looks easy to
> fix but so far I've been unable to find out where to include the
necessary -latomic [1]:
This was introduced by:

commit 3f7c3e84ad69f1ffa767b1b7ce3aa36de6c30f87 (refs/bisect/bad)
Author: Vitaly Buka <vitalybuka at google.com>
Date:   Thu Sep 10 19:59:31 2020 -0700

    [Asan] Fix __asan_update_allocation_context
    
    Update both thread and stack.
    Update thread and stack as atomic operation.
    Keep all 32bit of TID as now we have enough bits.
    
    Depends on D87135.
    
    Reviewed By: morehouse
    
    Differential Revision: https://reviews.llvm.org/D87217

Any suggestions on how to fix this? Passing -latomic for the offending linker
command doesn't
help, unfortunately.

A Linux SPARC porterbox (which I used for bisecting this) is available in the
GCC compile farm [1].

Adrian
> [1] https://gcc.gnu.org/wiki/CompileFarm
-- 
 .''`.  John Paul Adrian Glaubitz
: :' :  Debian Developer - glaubitz at debian.org
`. `'   Freie Universitaet Berlin - glaubitz at physik.fu-berlin.de
  `-    GPG: 62FF 8A75 84E0 2956 9546  0006 7426 3B37 F5B5 F913

Hi!

On 10/22/20 12:28 AM, John Paul Adrian Glaubitz via llvm-dev
wrote:
> On 10/21/20 8:19 PM, John Paul Adrian Glaubitz wrote:
>> The build on linux-sparcv9 has recently started to fail with a linker
failure that looks easy to
>> fix but so far I've been unable to find out where to include the
necessary -latomic [1]:
> 
> This was introduced by:
So, the build actually fails in the 32-bit libraries and I think the main
problem is in [1]:

The way atomic_load/store on 32 bits are implemented is just weird. The code
could just use
__atomic_load() and __atomic_store() [2].

The build doesn't fail on x86 and MIPS because these architectures have
custom headers for
this code. Not sure about PPC but it looks like the code is disabled on PPC
completely?

Adrian
> [1]
https://github.com/llvm/llvm-project/blob/master/compiler-rt/lib/sanitizer_common/sanitizer_atomic_clang.h
> [2] https://gcc.gnu.org/onlinedocs/gcc/_005f_005fatomic-Builtins.html
-- 
 .''`.  John Paul Adrian Glaubitz
: :' :  Debian Developer - glaubitz at debian.org
`. `'   Freie Universitaet Berlin - glaubitz at physik.fu-berlin.de
  `-    GPG: 62FF 8A75 84E0 2956 9546  0006 7426 3B37 F5B5 F913