[all-commits] [llvm/llvm-project] a64ea1: [llvm] [lit] Fix use_lld() to respect llvm_shlib_dir

[Michał Górny via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: a64ea173d7b152678780d5443407d1071277642b
      https://github.com/llvm/llvm-project/commit/a64ea173d7b152678780d5443407d1071277642b
  Author: Michał Górny <mgorny at gentoo.org>
  Date:   2022-10-07 (Fri, 07 Oct 2022)

  Changed paths:
    M llvm/utils/lit/lit/llvm/config.py

  Log Message:
  -----------
  [llvm] [lit] Fix use_lld() to respect llvm_shlib_dir

Fix the use_lld() to use llvm_shlib_dir similarly to how use_clang()
does it.  This fixes use_lld() wrongly prepending llvm_libs_dir,
i.e. the directory with system-installed LLVM libraries before
the build directory of standalone build.  As a result, the shared
libraries from an earlier version of clang end up being used instead of
the newly built version when running the test suite prior to installing.

To reproduce the problem, build and install LLVM with dylibs first,
e.g.:

    cmake ../llvm -G Ninja -DCMAKE_BUILD_TYPE=MinSizeRel \
      -DCMAKE_INSTALL_PREFIX="${HOME}"/llvm-test \
      -DLLVM_BUILD_LLVM_DYLIB=ON -DLLVM_LINK_LLVM_DYLIB=ON \
      -DLLVM_INSTALL_UTILS=ON
    ninja install

Then build clang against that installation and run tests:

    export LD_LIBRARY_PATH=~/llvm-test/lib
    export PATh=~/llvm-test/bin:"${PATH}"
    cmake ../clang -G Ninja -DCMAKE_BUILD_TYPE=MinSizeRel \
      -DCMAKE_INSTALL_PREFIX="${HOME}"/llvm-test \
      -DCLANG_LINK_CLANG_DYLIB=ON -DLLVM_BUILD_TESTS=ON \
      -DLLVM_EXTERNAL_LIT="${PWD}"/bin/llvm-lit
    ninja check-clang

The tests will be run with LD_LIBRARY_PATH of:

    /home/${USER}/llvm-test/lib:/home/${USER}/llvm-project/build-clang/lib

As a result, installed libclang-cpp will take precedence over the one
from build dir.  With the patch, the correct path is used, i.e.:

    /home/${USER}/llvm-project/build-clang/lib:/home/${USER}/llvm-test/lib

Differential Revision: https://reviews.llvm.org/D135368