[compiler-rt] Use the runtimes build for custom libc++

[phosek]

Summary

Some of the compiler-rt runtimes use custom instrumented libc++ build.
Use the runtimes build for building this custom libc++.

[ldionne]

LGTM but I do have some questions.

Really happy to see this refactoring! 🥳

compiler-rt/cmake/Modules/AddCompilerRT.cmake

637–647

What is that libcxx|libcxxabi syntax?

Edit: Nevermind, I just saw the LIST_SEPARATOR thing below. Clever, maybe a bit too much. Any reason not to use -DLLVM_ENABLE_RUNTIMES="libcxx;libcxxabi"?

648

Why do you need this setting?

compiler-rt/cmake/Modules/CustomLibcxx/CMakeLists.txt

1

I am SO happy to see this go away.

[ldionne]

Oh, also, note that compiler-rt isn't being run in the pre-commit CI tests, so please don't rely on that for validating this patch.

[phosek]

compiler-rt/cmake/Modules/AddCompilerRT.cmake

637–647

I tried that initially but it doesn't work, CMake interprets it as list of two strings: -DLLVM_ENABLE_RUNTIMES="libcxx and libcxxabi".

648

Great question, I copied it from the original file but I don't think these should be needed anymore.

compiler-rt/cmake/Modules/AddCompilerRT.cmake

if(NOT COMPILER_RT_STANDALONE_BUILD AND NOT LLVM_RUNTIMES_BUILD)
       set(toolchain_deps $<TARGET_FILE:clang>)
       set(force_deps DEPENDS $<TARGET_FILE:clang>)
     endif()
   else()
     set(compiler_args -DCMAKE_C_COMPILER=${CMAKE_C_COMPILER}
                       -DCMAKE_CXX_COMPILER=${CMAKE_CXX_COMPILER})
   endif()
 
-  set(STAMP_DIR ${prefix}-stamps/)
-  set(BINARY_DIR ${prefix}-bins/)
-
   add_custom_target(${name}-clear
-    COMMAND ${CMAKE_COMMAND} -E remove_directory ${BINARY_DIR}
-    COMMAND ${CMAKE_COMMAND} -E remove_directory ${STAMP_DIR}
-    COMMENT "Clobbering ${name} build and stamp directories"
+    COMMAND ${CMAKE_COMMAND} -E remove_directory ${prefix}
+    COMMENT "Clobbering ${name} build directories"
     USES_TERMINAL
     )
   set_target_properties(${name}-clear PROPERTIES FOLDER "Compiler-RT Misc")
 
   add_custom_command(
     OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/${name}-clobber-stamp
     DEPENDS ${LIBCXX_DEPS} ${toolchain_deps}
-    COMMAND ${CMAKE_COMMAND} -E touch ${BINARY_DIR}/CMakeCache.txt
-    COMMAND ${CMAKE_COMMAND} -E touch ${STAMP_DIR}/${name}-mkdir
+    COMMAND ${CMAKE_COMMAND} -E touch ${prefix}/CMakeCache.txt
     COMMAND ${CMAKE_COMMAND} -E touch ${CMAKE_CURRENT_BINARY_DIR}/${name}-clobber-stamp
-    COMMENT "Clobbering bootstrap build and stamp directories"
+    COMMENT "Clobbering bootstrap build directories"
     )
 
   add_custom_target(${name}-clobber
     DEPENDS ${CMAKE_CURRENT_BINARY_DIR}/${name}-clobber-stamp)
   set_target_properties(${name}-clobber PROPERTIES FOLDER "Compiler-RT Misc")
 
   set(PASSTHROUGH_VARIABLES
     CMAKE_C_COMPILER_TARGET
macro(add_custom_libcxx name prefix)
   set(LIBCXX_C_FLAGS "${LIBCXX_C_FLAGS} ${C_FLAGS}")
 
   string(REPLACE ";" " " LIBCXX_CXX_FLAGS "${LIBCXX_CFLAGS}")
   get_property(CXX_FLAGS CACHE CMAKE_CXX_FLAGS PROPERTY VALUE)
   set(LIBCXX_CXX_FLAGS "${LIBCXX_CXX_FLAGS} ${CXX_FLAGS}")
 
   ExternalProject_Add(${name}
     DEPENDS ${name}-clobber ${LIBCXX_DEPS}
-    PREFIX ${prefix}
-    SOURCE_DIR ${COMPILER_RT_SOURCE_DIR}/cmake/Modules/CustomLibcxx
-    STAMP_DIR ${STAMP_DIR}
-    BINARY_DIR ${BINARY_DIR}
+    PREFIX ${CMAKE_CURRENT_BINARY_DIR}/${name}
+    SOURCE_DIR ${LLVM_MAIN_SRC_DIR}/../runtimes
+    BINARY_DIR ${prefix}
     CMAKE_ARGS ${CMAKE_PASSTHROUGH_VARIABLES}
                ${compiler_args}
                -DCMAKE_C_FLAGS=${LIBCXX_C_FLAGS}
                -DCMAKE_CXX_FLAGS=${LIBCXX_CXX_FLAGS}
                -DCMAKE_BUILD_TYPE=Release
                -DCMAKE_TRY_COMPILE_TARGET_TYPE=STATIC_LIBRARY
                -DLLVM_PATH=${LLVM_MAIN_SRC_DIR}
-               -DLLVM_BINARY_DIR=${prefix}
-               -DLLVM_LIBRARY_OUTPUT_INTDIR=${prefix}/lib
-               -DCOMPILER_RT_LIBCXX_PATH=${COMPILER_RT_LIBCXX_PATH}
-               -DCOMPILER_RT_LIBCXXABI_PATH=${COMPILER_RT_LIBCXXABI_PATH}
+               -DLLVM_ENABLE_RUNTIMES=libcxx|libcxxabi
+               -DLIBCXXABI_ENABLE_SHARED=OFF
+               -DLIBCXXABI_ENABLE_EXCEPTIONS=OFF
+               -DLIBCXXABI_HERMETIC_STATIC_LIBRARY=ON
+               -DLIBCXXABI_INCLUDE_TESTS=OFF
+               -DLIBCXX_ENABLE_EXPERIMENTAL_LIBRARY=OFF
+               -DLIBCXX_ENABLE_SHARED=OFF
+               -DLIBCXX_ENABLE_EXCEPTIONS=OFF
+               -DLIBCXX_HERMETIC_STATIC_LIBRARY=ON
+               -DLIBCXX_INCLUDE_TESTS=OFF
+               -DLIBCXX_ENABLE_STATIC_ABI_LIBRARY=ON
                ${LIBCXX_CMAKE_ARGS}
     INSTALL_COMMAND ""
     STEP_TARGETS configure build
     BUILD_ALWAYS 1
     USES_TERMINAL_CONFIGURE 1
     USES_TERMINAL_BUILD 1
     USES_TERMINAL_INSTALL 1
+    LIST_SEPARATOR |
     EXCLUDE_FROM_ALL TRUE
-    BUILD_BYPRODUCTS "${prefix}/lib/libc++.a" "${prefix}/lib/libc++abi.a"
     )
 
   if (CMAKE_GENERATOR MATCHES "Make")
-    set(run_clean "$(MAKE)" "-C" "${BINARY_DIR}" "clean")
+    set(run_clean "$(MAKE)" "-C" "${prefix}" "clean")
   else()
-    set(run_clean ${CMAKE_COMMAND} --build ${BINARY_DIR} --target clean
+    set(run_clean ${CMAKE_COMMAND} --build ${prefix} --target clean
                                    --config "$<CONFIG>")
   endif()
 
   ExternalProject_Add_Step(${name} clean
     COMMAND ${run_clean}
     COMMENT "Cleaning ${name}..."
     DEPENDEES configure
     ${force_deps}
-    WORKING_DIRECTORY ${BINARY_DIR}
+    WORKING_DIRECTORY ${prefix}
     EXCLUDE_FROM_MAIN 1
     USES_TERMINAL 1
     )
   ExternalProject_Add_StepTargets(${name} clean)
 
   if(LIBCXX_USE_TOOLCHAIN)
     add_dependencies(${name}-clean ${name}-clobber)
     set_target_properties(${name}-clean PROPERTIES

compiler-rt/cmake/Modules/CustomLibcxx/CMakeLists.txt

-# TODO(phosek): We should use the runtimes build instead configured with
-# LLVM_ENABLE_RUNTIMES=libcxxabi;libcxx to avoid duplication of logic.
-
-cmake_minimum_required(VERSION 3.13.4)
-project(custom-libcxx C CXX)
-
-find_package(Python3 REQUIRED COMPONENTS Interpreter)
-
-# Build static libcxxabi.
-set(LIBCXXABI_ENABLE_SHARED OFF CACHE BOOL "")
-set(LIBCXXABI_ENABLE_EXCEPTIONS ON CACHE BOOL "")
-set(LIBCXXABI_HERMETIC_STATIC_LIBRARY ON CACHE STRING "")
-set(LIBCXXABI_LIBCXX_PATH ${COMPILER_RT_LIBCXX_PATH} CACHE PATH "")
-set(LIBCXXABI_INCLUDE_TESTS OFF CACHE BOOL "")
-add_subdirectory(${COMPILER_RT_LIBCXXABI_PATH} ${CMAKE_CURRENT_BINARY_DIR}/cxxabi)
-
-# Build static libcxx without exceptions.
-set(LIBCXX_ENABLE_EXPERIMENTAL_LIBRARY OFF CACHE BOOL "")
-set(LIBCXX_ENABLE_SHARED OFF CACHE BOOL "")
-set(LIBCXX_ENABLE_EXCEPTIONS OFF CACHE BOOL "")
-set(LIBCXX_HERMETIC_STATIC_LIBRARY ON CACHE BOOL "")
-
-# Use above libcxxabi.
-set(LIBCXX_CXX_ABI "libcxxabi" CACHE STRING "")
-set(LIBCXX_CXX_ABI_INTREE 1)
-set(LIBCXX_ENABLE_STATIC_ABI_LIBRARY ON CACHE BOOL "")
-set(LIBCXX_CXX_ABI_INCLUDE_PATHS ${COMPILER_RT_LIBCXXABI_PATH}/include CACHE PATH "")
-
-add_subdirectory(${COMPILER_RT_LIBCXX_PATH} ${CMAKE_CURRENT_BINARY_DIR}/cxx)