CMake files do not respect the LLVM config files from the custom installation

[flipreverse]

• [X ] I have searched open and closed issues for duplicates
• [ X] I made sure that I am not using an old project version (DO: pull PhASAR, update git submodules, rebuild the project and check if the bug is still there)

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Bug description

CMake does not use the include directory of the self-built LLVM/clang.

Steps to reproduce

• Use an LLVM version greater than 14 due a bug when building it on Debian 12
• Build steps
  • Run bootstrap.sh
  • Manually
    • CC=/fs/scratch/al/llvm-14/bin/clang CXX=/fs/scratch/al/llvm-14/bin/clang++ cmake -G Ninja -DCMAKE_BUILD_TYPE=Release -DPHASAR_BUILD_UNITTESTS=true /fs/scratch/al/phasar/src
    • cmake --build . -j 1

Actual result: Due to the newer LLVM, the build process aborts. This in turn shows the wrong include dir: -I/usr/lib/llvm-14/include.

/fs/scratch/al/llvm-14/bin/clang++ -DBOOST_ALL_NO_LIB -DBOOST_GRAPH_DYN_LINK -DBOOST_REGEX_DYN_LINK -DPHASAR_BUILD_DIR=\"/fs/scratch/al/phasar/src/build\" -DPHASAR_SRC_DIR=\"/fs/scratch/al/phasar/src\" -D_GNU_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -I/usr/lib/llvm-14/include -I/fs/scratch/al/phasar/src/include -I/fs/scratch/al/phasar/src/build/include -I/fs/scratch/al/phasar/src/external/json/include -I/fs/scratch/al/phasar/src/external/json-schema-validator/src -MP -fstack-protector-strong -ffunction-sections -fdata-sections -pipe -Wall -Wextra -Wno-unused-parameter -O3 -DNDEBUG -march=native -fPIC -fvisibility-inlines-hidden -std=c++17 -MD -MT lib/CMakeFiles/phasar.dir/LibPhasar.cpp.o -MF lib/CMakeFiles/phasar.dir/LibPhasar.cpp.o.d -o lib/CMakeFiles/phasar.dir/LibPhasar.cpp.o -c /fs/scratch/al/phasar/src/lib/LibPhasar.cpp

Expected result: The CMake files should honor the custom LLVM installation. The parameter -I/usr/lib/llvm-14/include should be replaced by -I/fs/scratch/al/llvm-14//include.

(Important /fs/scratch/al/llvm-14/ does contain a built of LLVM 17.0.6. The directory name is misleading.)

Context (Environment)

• phasar: [b796f7d44681514f58a683a3a71ff17c94edb0c1]
• googletest: [b07f56a]
• json: [bc889afb4c5bf1c0d8ee29ef35eaaf4c8bef8a5d]
• json-schema-validator [491ac44026e08f31790f5cacffa62e168bb35e32]

Operating System:

• [X ] Linux
• Windows
• macOS

Build Type:

• [ X] cmake
• [ X] bootstrap.sh
• custom build

Possible solution

The CMake variable LLVM_INCLUDE_DIRS, used in cmake/phasar_macros.cmake:209 shall point to the aforementioned directory.
That variable is set in /fs/scratch/al/llvm-14/lib/cmake/llvm/LLVMConfig.cmake. I assume CMake must use the CMake files for LLVM from /fs/scratch/al/llvm-14/lib/cmake.

Example files

Files:

[fabianbs96]

Hi @flipreverse,

PhASAR currently requires LLVM 14. We are in the process of supporting newer LLVM versions, but there are two major problems that have to be solved first (#533 and #687).

In our build configuration, we use find_package(LLVM 14 REQUIRED CONFIG) to find the required LLVM version. Even if there is a newer version installed, this command will prefer LLVM 14.
Please note, that this LLVM version is independent from the clang version that you use for compilation -- you just cannot compile the unittests with clang>14.
Your invocation

CC=/fs/scratch/al/llvm-14/bin/clang CXX=/fs/scratch/al/llvm-14/bin/clang++ cmake -G Ninja -DCMAKE_BUILD_TYPE=Release -DPHASAR_BUILD_UNITTESTS=true /fs/scratch/al/phasar/src

only changes the compiler, but has no influence on the LLVM version that phasar links against.

In order to use a different LLVM version, you would need to modify the corresponding line in our top-level CMakeLists.txt.