Fix integration of pass plugins with llvm dylib

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Summary

• Call llvm_process_pass_plugin from clang when in standalone mode
• bug spotted in https://github.com/llvm/llvm-project/issues/120 and recorded as https://bugs.llvm.org/show_bug.cgi?id=44870

[hans]

I don't know enough about the cmake and dylib build to properly review this. Maybe Tom can help?

Please add a mention of https://github.com/llvm/llvm-project/issues/120 / https://bugs.llvm.org/show_bug.cgi?id=44870 in the change description.

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Need to pull in the symbols, provide the appropriate anchor

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tested with

cmake -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=/tmp/inst -DLLVM_LINK_LLVM_DYLIB=ON -DLLVM_BUILD_LLVM_DYLIB=ON   -DLLVM_POLLY_LINK_INTO_TOOLS=ON -DLLVM_TOOL_POLLY_BUILD=ON -DPOLLY_BUNDLED_ISL=ON ../llvm && make -j30  && nm -DC lib/libLLVM-11git.so | grep getPollyPluginInfo

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Also pass with

cmake -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=/tmp/inst -DLLVM_LINK_LLVM_DYLIB=OFF -DLLVM_BUILD_LLVM_DYLIB=OFF   -DLLVM_POLLY_LINK_INTO_TOOLS=ON -DLLVM_TOOL_POLLY_BUILD=ON -DPOLLY_BUNDLED_ISL=ON ../llvm && make -j30 && make check-polly -j20

(i.e. when no using DYLIB but still linking polly statically)

and

cmake -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=/tmp/inst -DLLVM_LINK_LLVM_DYLIB=OFF -DLLVM_BUILD_LLVM_DYLIB=OFF   -DLLVM_POLLY_LINK_INTO_TOOLS=OFF -DLLVM_TOOL_POLLY_BUILD=ON -DPOLLY_BUNDLED_ISL=ON ../llvm && make -j30 && make check-polly -j20

(i.e. when not using dylib and not linking polly statically)

and

cmake -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=/tmp/inst -DLLVM_LINK_LLVM_DYLIB=ON -DLLVM_BUILD_LLVM_DYLIB=ON   -DLLVM_POLLY_LINK_INTO_TOOLS=OFF -DLLVM_TOOL_POLLY_BUILD=ON -DPOLLY_BUNDLED_ISL=ON ../llvm && make -j30 && make check-polly -j20

(i.e. when using dylib but without polly linked in statically)

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But it fails (registered twice) when using LLVM_ENABLE_PROJECTS instead... That's definitively a lot of configuration :-

Actually a configuration issue on my side, everything works file with that config too.

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Totally different, and much cleaner approach of the issue.

[hans]

Looks reasonable to me.

clang/CMakeLists.txt

 
 if (LLVM_ADD_NATIVE_VISUALIZERS_TO_SOLUTION)
   add_subdirectory(utils/ClangVisualizers)
 endif()
 add_subdirectory(utils/hmaptool)
 
 if(CLANG_BUILT_STANDALONE)
   llvm_distribution_add_targets()
+  process_llvm_pass_plugins()
 endif()
 
 configure_file(
   ${CLANG_SOURCE_DIR}/include/clang/Config/config.h.cmake
   ${CLANG_BINARY_DIR}/include/clang/Config/config.h)

llvm/CMakeLists.txt

if(LLVM_LIBS)
     endforeach()
   endif()
 endif()
 
 # This must be at the end of the LLVM root CMakeLists file because it must run
 # after all targets are created.
 include(LLVMDistributionSupport)
 llvm_distribution_add_targets()
+process_llvm_pass_plugins()
 
 # This allows us to deploy the Universal CRT DLLs by passing -DCMAKE_INSTALL_UCRT_LIBRARIES=ON to CMake
 if (MSVC AND CMAKE_HOST_SYSTEM_NAME STREQUAL "Windows" AND CMAKE_INSTALL_UCRT_LIBRARIES)
   include(InstallRequiredSystemLibraries)
 endif()
 
 if (LLVM_INCLUDE_BENCHMARKS)
   # Override benchmark defaults so that when the library itself is updated these
   # modifications are not lost.
   set(BENCHMARK_ENABLE_TESTING OFF CACHE BOOL "Disable benchmark testing" FORCE)
   set(BENCHMARK_ENABLE_EXCEPTIONS OFF CACHE BOOL "Disable benchmark exceptions" FORCE)
   set(BENCHMARK_ENABLE_INSTALL OFF CACHE BOOL "Don't install benchmark" FORCE)
   set(BENCHMARK_DOWNLOAD_DEPENDENCIES OFF CACHE BOOL "Don't download dependencies" FORCE)
   set(BENCHMARK_ENABLE_GTEST_TESTS OFF CACHE BOOL "Disable Google Test in benchmark" FORCE)
   # Since LLVM requires C++11 it is safe to assume that std::regex is available.
   set(HAVE_STD_REGEX ON CACHE BOOL "OK" FORCE)
 
   add_subdirectory(utils/benchmark)
   add_subdirectory(benchmarks)
 endif()
 
 if (LLVM_INCLUDE_UTILS AND LLVM_INCLUDE_TOOLS)
   add_subdirectory(utils/llvm-locstats)
 endif()
-
-process_llvm_pass_plugins()