[llvm-libgcc] Fix symlink path for libcc when LLVM_ENABLE_PER_TARGET_… #165487
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The symlink for libgcc_so.1.0 is made to point to libunwind.so which is functionally correct but it fails some linux distro packaging complain because libunwind.so is made part of -dev package but libgcc_so.1.0 ends up in the real package, and creates an unneeded package -> dev dependency create the symlink to point to libunwind.so.1 instead then the boundaries of packaging are not crossed and all is well.
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…UNTIME_DIR=OFF The llvm-libgcc installation was creating incorrect symlinks for libgcc.a when built with LLVM_ENABLE_PER_TARGET_RUNTIME_DIR=OFF, particularly seen with Yocto cross-compilation environments. Issues seen: - Absolute path in symlink: The previous code didn't handle absolute paths returned by get_compiler_rt_install_dir() in staging/sysroot environments, resulting in symlinks like: libgcc.a -> /absolute/path/to/sysroot/usr/lib/clang/.../libclang_rt.builtins.a - Missing architecture suffix: When the install path contained "clang", the code would skip setting builtins_suffix, creating: libgcc.a -> clang/21.1.4/lib/linux/libclang_rt.builtins.a instead of: libgcc.a -> clang/21.1.4/lib/linux/libclang_rt.builtins-aarch64.a - Incorrect relative path calculation: The original regex stripped too much or too little of the path, either creating symlinks pointing to non-existent locations or stripping the clang/ directory prefix entirely. Solution: - Extract the relative path starting from 'clang/' when present in absolute paths, ensuring the symlink points to the correct location within the installation hierarchy - Always append the architecture suffix to the builtins library name - Only prepend '../' to the path when LLVM_ENABLE_PER_TARGET_RUNTIME_DIR is enabled, as this is when the builtins are in a different directory level The symlink now correctly points to the existing compiler-rt builtins library without creating duplicate copies. Tested with LLVM_ENABLE_PER_TARGET_RUNTIME_DIR=OFF in cross-compilation environments (aarch64 target).
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…RUNTIME_DIR is unset
current logic fails when LLVM_ENABLE_PER_TARGET_RUNTIME_DIR = OFF and it ends up with symlinks e.g.
libgcc.a -> ..//usr/lib/clang/21.1.4/lib/linux/libclang_rt.builtins.a
the real library is at
../lib/clang/21.1.4/lib/linux/libclang_rt.builtins-aarch64.a
The relative path is incorrect and its missing to add -arch suffix as well.
So we make checks a bit more explicit to cover this case.
The symlink for libgcc_so.1.0 is made to point to libunwind.so which is functionally correct but it fails some linux distro packaging complain because libunwind.so is made part of -dev package but libgcc_so.1.0 ends up in the real package, and creates an unneeded package -> dev dependency
create the symlink to point to libunwind.so.1 instead then the boundaries of packaging are not crossed and all is well.