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| author | Louis Dionne <ldionne.2@gmail.com> | 2023-09-21 05:10:05 -0400 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2023-09-21 05:10:05 -0400 |
| commit | e46de4e54f63eb4088ca351253768b5db8cf1985 (patch) | |
| tree | 849a3e28ad68f84e5d0500b406d07a935e5604f5 /libunwind | |
| parent | 3bd7a9b47badd22b21f5b53ddeffe550a0c1f338 (diff) | |
| download | llvm-e46de4e54f63eb4088ca351253768b5db8cf1985.zip llvm-e46de4e54f63eb4088ca351253768b5db8cf1985.tar.gz llvm-e46de4e54f63eb4088ca351253768b5db8cf1985.tar.bz2 | |
[runtimes] Fix link order of system librarires on Apple platforms (#66940)
On Apple platforms, we always support the -nostdlib++ flag. Hence, it is
not necessary to manually link against system libraries. In fact, doing
so causes us to link against libSystem explicitly, which messes up with
the order of libraries we should use. Indeed:
Before patch, using the system unwinder (LIBCXXABI_USE_LLVM_UNWINDER = OFF)
===========================================================================
$ otool -L lib/{libc++.1.dylib,libc++abi.1.dylib,libunwind.1.dylib}
lib/libc++.1.dylib:
@rpath/libc++.1.dylib
/usr/lib/libSystem.B.dylib
@rpath/libc++abi.1.dylib
lib/libc++abi.1.dylib:
@rpath/libc++abi.1.dylib
/usr/lib/libSystem.B.dylib
lib/libunwind.1.dylib:
@rpath/libunwind.1.dylib
/usr/lib/libSystem.B.dylib
After patch, using the system unwinder (LIBCXXABI_USE_LLVM_UNWINDER = OFF)
===========================================================================
$ otool -L lib/{libc++.1.dylib,libc++abi.1.dylib,libunwind.1.dylib}
lib/libc++.1.dylib:
@rpath/libc++.1.dylib
@rpath/libc++abi.1.dylib
/usr/lib/libSystem.B.dylib
lib/libc++abi.1.dylib:
@rpath/libc++abi.1.dylib
/usr/lib/libSystem.B.dylib
lib/libunwind.1.dylib:
@rpath/libunwind.1.dylib
/usr/lib/libSystem.B.dylib
Before patch, with the LLVM unwinder (LIBCXXABI_USE_LLVM_UNWINDER = ON)
=======================================================================
$ otool -L lib/{libc++.1.dylib,libc++abi.1.dylib,libunwind.1.dylib}
lib/libc++.1.dylib:
@rpath/libc++.1.dylib
/usr/lib/libSystem.B.dylib
@rpath/libc++abi.1.dylib
@rpath/libunwind.1.dylib
lib/libc++abi.1.dylib:
@rpath/libc++abi.1.dylib
/usr/lib/libSystem.B.dylib
@rpath/libunwind.1.dylib
lib/libunwind.1.dylib:
@rpath/libunwind.1.dylib
/usr/lib/libSystem.B.dylib
After patch, with the LLVM unwinder (LIBCXXABI_USE_LLVM_UNWINDER = ON)
======================================================================
$ otool -L lib/{libc++.1.dylib,libc++abi.1.dylib,libunwind.1.dylib}
lib/libc++.1.dylib:
@rpath/libc++.1.dylib
@rpath/libc++abi.1.dylib
@rpath/libunwind.1.dylib
/usr/lib/libSystem.B.dylib
lib/libc++abi.1.dylib:
@rpath/libc++abi.1.dylib
@rpath/libunwind.1.dylib
/usr/lib/libSystem.B.dylib
lib/libunwind.1.dylib:
@rpath/libunwind.1.dylib
/usr/lib/libSystem.B.dylib
As we can see, libSystem appears before the just-built libraries before
the patch, which causes the libunwind.dylib bundled in libSystem.dylib
to be used instead of the just-built libunwind.dylib.
We didn't notice the issue until recently when I tried to update the
macOS CI builders to macOS 13.5, where it is necessary to use the right
libunwind library (the exact reason still needs to be investigated).
Diffstat (limited to 'libunwind')
| -rw-r--r-- | libunwind/src/CMakeLists.txt | 13 |
1 files changed, 10 insertions, 3 deletions
diff --git a/libunwind/src/CMakeLists.txt b/libunwind/src/CMakeLists.txt index a9bf29a8..452d988 100644 --- a/libunwind/src/CMakeLists.txt +++ b/libunwind/src/CMakeLists.txt @@ -65,16 +65,23 @@ set(LIBUNWIND_SOURCES ${LIBUNWIND_ASM_SOURCES}) # Generate library list. -add_library_flags_if(LIBUNWIND_HAS_C_LIB c) if (LIBUNWIND_USE_COMPILER_RT) add_library_flags("${LIBUNWIND_BUILTINS_LIBRARY}") else() add_library_flags_if(LIBUNWIND_HAS_GCC_S_LIB gcc_s) add_library_flags_if(LIBUNWIND_HAS_GCC_LIB gcc) endif() -add_library_flags_if(LIBUNWIND_HAS_DL_LIB dl) +if (NOT APPLE) # On Apple platforms, we don't need to link explicitly against system libraries + add_library_flags_if(LIBUNWIND_HAS_C_LIB c) + add_library_flags_if(LIBUNWIND_HAS_DL_LIB dl) + + if (LIBUNWIND_ENABLE_THREADS) + add_library_flags_if(LIBUNWIND_HAS_PTHREAD_LIB pthread) + add_compile_flags_if(LIBUNWIND_WEAK_PTHREAD_LIB -DLIBUNWIND_USE_WEAK_PTHREAD=1) + endif() +endif() + if (LIBUNWIND_ENABLE_THREADS) - add_library_flags_if(LIBUNWIND_HAS_PTHREAD_LIB pthread) add_compile_flags_if(LIBUNWIND_WEAK_PTHREAD_LIB -DLIBUNWIND_USE_WEAK_PTHREAD=1) endif() |