[runtimes] Use standalone build only for compiler-rt

compiler-rt needs to use standalone build because of the assumptions made by its build, but other runtimes can use non-standalone build. Differential Revision: https://reviews.llvm.org/D97575
intel · Mar 3, 2021 · 4e421b2 · 4e421b2
1 parent 84a50f5
commit 4e421b2
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Showing 2 changed files with 5 additions and 15 deletions.
diff --git a/compiler-rt/cmake/Modules/CustomLibcxx/CMakeLists.txt b/compiler-rt/cmake/Modules/CustomLibcxx/CMakeLists.txt
@@ -2,7 +2,6 @@ cmake_minimum_required(VERSION 3.13.4)
 project(custom-libcxx C CXX)
 
 # Build static libcxxabi.
-set(LIBCXXABI_STANDALONE_BUILD 1)
 set(LIBCXXABI_ENABLE_SHARED OFF CACHE BOOL "")
 set(LIBCXXABI_ENABLE_EXCEPTIONS ON CACHE BOOL "")
 set(LIBCXXABI_HERMETIC_STATIC_LIBRARY ON CACHE STRING "")
@@ -11,7 +10,6 @@ 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_STANDALONE_BUILD 1)
 set(LIBCXX_ENABLE_EXPERIMENTAL_LIBRARY OFF CACHE BOOL "")
 set(LIBCXX_ENABLE_SHARED OFF CACHE BOOL "")
 set(LIBCXX_ENABLE_EXCEPTIONS OFF CACHE BOOL "")

diff --git a/runtimes/CMakeLists.txt b/runtimes/CMakeLists.txt
@@ -82,10 +82,6 @@ include(CheckCCompilerFlag)
 # these flags.
 if (NOT MSVC)
   set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -nostdinc++ -nostdlib++")
-
-  if (LLVM_EXTERNAL_LIBCXX_SOURCE_DIR AND "libcxx" IN_LIST LLVM_ENABLE_RUNTIMES)
-    set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -isystem ${LLVM_EXTERNAL_LIBCXX_SOURCE_DIR}/include")
-  endif()
 endif()
 
 # Avoid checking whether the compiler is working.
@@ -96,9 +92,6 @@ include(AddLLVM)
 include(HandleLLVMOptions)
 include(FindPythonInterp)
 
-# Remove the -nostdlib++ option we've added earlier.
-string(REPLACE "-nostdlib++" "" CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS}")
-
 # Use libtool instead of ar if you are both on an Apple host, and targeting Apple.
 if(CMAKE_HOST_APPLE AND APPLE)
   include(UseLibtool)
@@ -114,12 +107,11 @@ foreach(entry ${runtimes})
   string(REPLACE "-" "_" canon_name ${projName})
   string(TOUPPER ${canon_name} canon_name)
 
-  # The subdirectories need to treat this as standalone builds. D57992 tried
-  # to get rid of this, but the runtimes treat *_STANDALONE_BUILD=OFF as if
-  # llvm & clang are configured in the same CMake, and setup dependencies
-  # against their targets. OpenMP has fixed the issue so we don't set the
-  # variable.
-  if (NOT ${canon_name} STREQUAL "OPENMP")
+  # TODO: compiler-rt has to use standalone build for now. We tried to remove
+  # this in D57992 but this broke the build because compiler-rt assumes that
+  # LLVM and Clang are configured in the same build to set up dependencies. We
+  # should clean up the compiler-rt build and remove this eventually.
+  if ("${canon_name}" STREQUAL "COMPILER_RT")
     set(${canon_name}_STANDALONE_BUILD ON)
   endif()