commit 55d6cb7a2aa2798414877d64b7a10cc856285a53
author Petr Hosek <phosek@google.com> Mon Sep 28 17:37:20 2020 -0700
committer Copybara-Service <copybara-worker@google.com> Mon Oct 18 14:45:25 2021 -0700
tree 8d6815b3458f63d57947d9a320ec77df4da28b58
parent c5e10c24d86571f47cec21879b0284e33f8ba45e

[CMake] Cache the compiler-rt library search results

There's a lot of duplicated calls to find various compiler-rt libraries
from build of runtime libraries like libunwind, libc++, libc++abi and
compiler-rt. The compiler-rt helper module already implemented caching
for results avoid repeated Clang invocations.

This change moves the compiler-rt implementation into a shared location
and reuses it from other runtimes to reduce duplication and speed up
the build.

Differential Revision: https://reviews.llvm.org/D88458

GitOrigin-RevId: 0eed292fbae22a8856682b07e1cb968424b49941

CMakeLists.txt

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 9b55195..7a8bfae 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -12,6 +12,8 @@
 set(CMAKE_MODULE_PATH
   "${CMAKE_CURRENT_SOURCE_DIR}/cmake"
   "${CMAKE_CURRENT_SOURCE_DIR}/cmake/Modules"
+  "${CMAKE_CURRENT_SOURCE_DIR}/../cmake"
+  "${CMAKE_CURRENT_SOURCE_DIR}/../cmake/Modules"
   ${CMAKE_MODULE_PATH}
   )
 

cmake/Modules/HandleCompilerRT.cmake

diff --git a/cmake/Modules/HandleCompilerRT.cmake b/cmake/Modules/HandleCompilerRT.cmake
deleted file mode 100644
index 77168e5..0000000
--- a/cmake/Modules/HandleCompilerRT.cmake
+++ /dev/null
@@ -1,64 +0,0 @@
-function(find_compiler_rt_library name dest)
-  if (NOT DEFINED LIBUNWIND_COMPILE_FLAGS)
-    message(FATAL_ERROR "LIBUNWIND_COMPILE_FLAGS must be defined when using this function")
-  endif()
-  set(dest "" PARENT_SCOPE)
-  set(CLANG_COMMAND ${CMAKE_CXX_COMPILER} ${LIBUNWIND_COMPILE_FLAGS}
-      "--rtlib=compiler-rt" "--print-libgcc-file-name")
-  if (CMAKE_CXX_COMPILER_ID MATCHES Clang AND CMAKE_CXX_COMPILER_TARGET)
-    list(APPEND CLANG_COMMAND "--target=${CMAKE_CXX_COMPILER_TARGET}")
-  endif()
-  get_property(LIBUNWIND_CXX_FLAGS CACHE CMAKE_CXX_FLAGS PROPERTY VALUE)
-  string(REPLACE " " ";" LIBUNWIND_CXX_FLAGS "${LIBUNWIND_CXX_FLAGS}")
-  list(APPEND CLANG_COMMAND ${LIBUNWIND_CXX_FLAGS})
-  execute_process(
-      COMMAND ${CLANG_COMMAND}
-      RESULT_VARIABLE HAD_ERROR
-      OUTPUT_VARIABLE LIBRARY_FILE
-  )
-  string(STRIP "${LIBRARY_FILE}" LIBRARY_FILE)
-  file(TO_CMAKE_PATH "${LIBRARY_FILE}" LIBRARY_FILE)
-  string(REPLACE "builtins" "${name}" LIBRARY_FILE "${LIBRARY_FILE}")
-  if (NOT HAD_ERROR AND EXISTS "${LIBRARY_FILE}")
-    message(STATUS "Found compiler-rt library: ${LIBRARY_FILE}")
-    set(${dest} "${LIBRARY_FILE}" PARENT_SCOPE)
-  else()
-    message(STATUS "Failed to find compiler-rt library")
-  endif()
-endfunction()
-
-function(find_compiler_rt_dir dest)
-  if (NOT DEFINED LIBUNWIND_COMPILE_FLAGS)
-    message(FATAL_ERROR "LIBUNWIND_COMPILE_FLAGS must be defined when using this function")
-  endif()
-  set(dest "" PARENT_SCOPE)
-  if (APPLE)
-    set(CLANG_COMMAND ${CMAKE_CXX_COMPILER} ${LIBUNWIND_COMPILE_FLAGS}
-        "-print-file-name=lib")
-    execute_process(
-        COMMAND ${CLANG_COMMAND}
-        RESULT_VARIABLE HAD_ERROR
-        OUTPUT_VARIABLE LIBRARY_DIR
-    )
-    string(STRIP "${LIBRARY_DIR}" LIBRARY_DIR)
-    file(TO_CMAKE_PATH "${LIBRARY_DIR}" LIBRARY_DIR)
-    set(LIBRARY_DIR "${LIBRARY_DIR}/darwin")
-  else()
-    set(CLANG_COMMAND ${CMAKE_CXX_COMPILER} ${LIBUNWIND_COMPILE_FLAGS}
-        "--rtlib=compiler-rt" "--print-libgcc-file-name")
-    execute_process(
-        COMMAND ${CLANG_COMMAND}
-        RESULT_VARIABLE HAD_ERROR
-        OUTPUT_VARIABLE LIBRARY_FILE
-    )
-    string(STRIP "${LIBRARY_FILE}" LIBRARY_FILE)
-    file(TO_CMAKE_PATH "${LIBRARY_FILE}" LIBRARY_FILE)
-    get_filename_component(LIBRARY_DIR "${LIBRARY_FILE}" DIRECTORY)
-  endif()
-  if (NOT HAD_ERROR AND EXISTS "${LIBRARY_DIR}")
-    message(STATUS "Found compiler-rt directory: ${LIBRARY_DIR}")
-    set(${dest} "${LIBRARY_DIR}" PARENT_SCOPE)
-  else()
-    message(STATUS "Failed to find compiler-rt directory")
-  endif()
-endfunction()

cmake/config-ix.cmake

diff --git a/cmake/config-ix.cmake b/cmake/config-ix.cmake
index 4ca6bdd..a7ad72f 100644
--- a/cmake/config-ix.cmake
+++ b/cmake/config-ix.cmake
@@ -40,7 +40,10 @@
     list(APPEND CMAKE_REQUIRED_LIBRARIES c)
   endif ()
   if (LIBUNWIND_USE_COMPILER_RT)
+    cmake_push_check_state()
+    set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} ${LIBUNWIND_COMPILE_FLAGS}")
     find_compiler_rt_library(builtins LIBUNWIND_BUILTINS_LIBRARY)
+    cmake_pop_check_state()
     list(APPEND CMAKE_REQUIRED_LIBRARIES "${LIBUNWIND_BUILTINS_LIBRARY}")
   else ()
     if (LIBUNWIND_HAS_GCC_S_LIB)