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

This reverts commit bda3f2dd76 since
it broke MSan tests.

compiler-rt/cmake/Modules/AddCompilerRT.cmake

@@ -565,9 +565,13 @@ macro(add_custom_libcxx name prefix)
                       -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 ${prefix}
-    COMMENT "Clobbering ${name} build directories"
+    COMMAND ${CMAKE_COMMAND} -E remove_directory ${BINARY_DIR}
+    COMMAND ${CMAKE_COMMAND} -E remove_directory ${STAMP_DIR}
+    COMMENT "Clobbering ${name} build and stamp directories"
     USES_TERMINAL
     )
   set_target_properties(${name}-clear PROPERTIES FOLDER "Compiler-RT Misc")
@@ -575,9 +579,10 @@ macro(add_custom_libcxx name prefix)
   add_custom_command(
     OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/${name}-clobber-stamp
     DEPENDS ${LIBCXX_DEPS} ${toolchain_deps}
-    COMMAND ${CMAKE_COMMAND} -E touch ${prefix}/CMakeCache.txt
+    COMMAND ${CMAKE_COMMAND} -E touch ${BINARY_DIR}/CMakeCache.txt
+    COMMAND ${CMAKE_COMMAND} -E touch ${STAMP_DIR}/${name}-mkdir
     COMMAND ${CMAKE_COMMAND} -E touch ${CMAKE_CURRENT_BINARY_DIR}/${name}-clobber-stamp
-    COMMENT "Clobbering bootstrap build directories"
+    COMMENT "Clobbering bootstrap build and stamp directories"
     )
 
   add_custom_target(${name}-clobber
@@ -624,9 +629,10 @@ macro(add_custom_libcxx name prefix)
 
   ExternalProject_Add(${name}
     DEPENDS ${name}-clobber ${LIBCXX_DEPS}
-    PREFIX ${CMAKE_CURRENT_BINARY_DIR}/${name}
-    SOURCE_DIR ${LLVM_MAIN_SRC_DIR}/../runtimes
-    BINARY_DIR ${prefix}
+    PREFIX ${prefix}
+    SOURCE_DIR ${COMPILER_RT_SOURCE_DIR}/cmake/Modules/CustomLibcxx
+    STAMP_DIR ${STAMP_DIR}
+    BINARY_DIR ${BINARY_DIR}
     CMAKE_ARGS ${CMAKE_PASSTHROUGH_VARIABLES}
                ${compiler_args}
                -DCMAKE_C_FLAGS=${LIBCXX_C_FLAGS}
@@ -634,17 +640,10 @@ macro(add_custom_libcxx name prefix)
                -DCMAKE_BUILD_TYPE=Release
                -DCMAKE_TRY_COMPILE_TARGET_TYPE=STATIC_LIBRARY
                -DLLVM_PATH=${LLVM_MAIN_SRC_DIR}
-               -DLLVM_ENABLE_RUNTIMES=libcxx|libcxxabi
-               -DLIBCXXABI_ENABLE_SHARED=OFF
-               -DLIBCXXABI_ENABLE_EXCEPTIONS=OFF
-               -DLIBCXXABI_HERMETIC_STATIC_LIBRARY=ON
-               -DLIBCXXABI_INCLUDE_TESTS=OFF
-               -DLIBCXX_ENABLE_EXPERIMENTAL_LIBRARY=OFF
-               -DLIBCXX_ENABLE_SHARED=OFF
-               -DLIBCXX_ENABLE_EXCEPTIONS=OFF
-               -DLIBCXX_HERMETIC_STATIC_LIBRARY=ON
-               -DLIBCXX_INCLUDE_TESTS=OFF
-               -DLIBCXX_ENABLE_STATIC_ABI_LIBRARY=ON
+               -DLLVM_BINARY_DIR=${prefix}
+               -DLLVM_LIBRARY_OUTPUT_INTDIR=${prefix}/lib
+               -DCOMPILER_RT_LIBCXX_PATH=${COMPILER_RT_LIBCXX_PATH}
+               -DCOMPILER_RT_LIBCXXABI_PATH=${COMPILER_RT_LIBCXXABI_PATH}
                ${LIBCXX_CMAKE_ARGS}
     INSTALL_COMMAND ""
     STEP_TARGETS configure build
@@ -652,15 +651,14 @@ macro(add_custom_libcxx name prefix)
     USES_TERMINAL_CONFIGURE 1
     USES_TERMINAL_BUILD 1
     USES_TERMINAL_INSTALL 1
-    LIST_SEPARATOR |
     EXCLUDE_FROM_ALL TRUE
     BUILD_BYPRODUCTS "${prefix}/lib/libc++.a" "${prefix}/lib/libc++abi.a"
     )
 
   if (CMAKE_GENERATOR MATCHES "Make")
-    set(run_clean "$(MAKE)" "-C" "${prefix}" "clean")
+    set(run_clean "$(MAKE)" "-C" "${BINARY_DIR}" "clean")
   else()
-    set(run_clean ${CMAKE_COMMAND} --build ${prefix} --target clean
+    set(run_clean ${CMAKE_COMMAND} --build ${BINARY_DIR} --target clean
                                    --config "$<CONFIG>")
   endif()
 
@@ -669,7 +667,7 @@ macro(add_custom_libcxx name prefix)
     COMMENT "Cleaning ${name}..."
     DEPENDEES configure
     ${force_deps}
-    WORKING_DIRECTORY ${prefix}
+    WORKING_DIRECTORY ${BINARY_DIR}
     EXCLUDE_FROM_MAIN 1
     USES_TERMINAL 1
     )

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

@@ -0,0 +1,29 @@
+# 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)