[CMake] Fix ASM building in llvm/runtimes

[Hahnfeld]

Summary

When compiler-rt's CMake is not directly invoked, it will currently not call project() and thus ASM will not be enabled.
We also don't need to put the .S files through the C compiler then.

@kubabrecka Could you test under OS X with XCode? I don't have the hardware at hand to make sure that works...

[beanz]

The Xcode generator doesn't work at all with the runtimes subdirectory (and I expect the same is true for Visual Studio). I haven't had a chance to figure out how to make it work correctly for IDEs yet, but that is on my TODO list. In the meantime, this patch LGTM.

[Hahnfeld]

In D23656#519869, @beanz wrote:

The Xcode generator doesn't work at all with the runtimes subdirectory (and I expect the same is true for Visual Studio). I haven't had a chance to figure out how to make it work correctly for IDEs yet, but that is on my TODO list. In the meantime, this patch LGTM.

And in projects or stand-alone? I saw that @kubabrecka added all these set_source_files_properties on the initial commit...

[beanz]

Xcode works fine in projects, which should be good enough. If @kubabrecka encounters issues we can solve them separately.

[beanz]

CMakeLists.txt

12

Actually, I do have one suggestion here. Make this:

if (CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR OR COMPILER_RT_STANDALONE_BUILD)

The runtimes subdirectory CMake file sets the *_STANDALONE_BUILD variable, so we can use it before it would be set in the normal standalone build.

[Hahnfeld]

CMakeLists.txt

12

Yes, I just saw your changes for libcxx and will do the change when commiting.

[Hahnfeld]

In D23656#520015, @beanz wrote:

Xcode works fine in projects, which should be good enough. If @kubabrecka encounters issues we can solve them separately.

Green dragon complained, I'll leave it to Apple on how to properly resolve the ASM building for TSAN as I can't test that myself:
http://lab.llvm.org:8080/green/job/clang-stage1-cmake-RA-globalisel_build/3645/
http://lab.llvm.org:8080/green/job/clang-stage1-configure-RA_build/23772/

CMakeLists.txt

 # CMake build for CompilerRT.
 #
 # This build assumes that CompilerRT is checked out into the
-# 'projects/compiler-rt' inside of an LLVM tree.
+# 'projects/compiler-rt' or 'runtimes/compiler-rt' inside of an LLVM tree.
 # Standalone build system for CompilerRT is not yet ready.
 #
 # An important constraint of the build is that it only produces libraries
 # based on the ability of the host toolchain to target various platforms.
 
-# Check if compiler-rt is built as a standalone project.
-if (CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
+# Check if compiler-rt is built as a standalone project or from inside the
+# runtimes directory.
+if (CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR OR
+    "${CMAKE_SOURCE_DIR}/compiler-rt" STREQUAL CMAKE_CURRENT_SOURCE_DIR)
   project(CompilerRT C CXX ASM)
   set(COMPILER_RT_STANDALONE_BUILD TRUE)
 endif()
 
 cmake_minimum_required(VERSION 3.4.3)
 # FIXME:
 # The OLD behavior (pre 3.2) for this policy is to not set the value of the 
 # CMAKE_EXE_LINKER_FLAGS variable in the generated test project. The NEW behavior

lib/tsan/CMakeLists.txt

set(TSAN_HEADERS
   rtl/tsan_vector.h)
 
 set(TSAN_RUNTIME_LIBRARIES)
 add_custom_target(tsan)
 set_target_properties(tsan PROPERTIES FOLDER "Compiler-RT Misc")
 
 if(APPLE)
   set(TSAN_ASM_SOURCES rtl/tsan_rtl_amd64.S)
-  # Xcode will try to compile this file as C ('clang -x c'), and that will fail.
-  if (${CMAKE_GENERATOR} STREQUAL "Xcode")
-    enable_language(ASM)
-  else()
-    # Pass ASM file directly to the C++ compiler.
-    set_source_files_properties(${TSAN_ASM_SOURCES} PROPERTIES LANGUAGE C)
-  endif()
   add_compiler_rt_runtime(clang_rt.tsan
     SHARED
     OS ${TSAN_SUPPORTED_OS}
     ARCHS ${TSAN_SUPPORTED_ARCH}
     SOURCES ${TSAN_SOURCES} ${TSAN_CXX_SOURCES} ${TSAN_ASM_SOURCES}
     OBJECT_LIBS RTInterception
                 RTSanitizerCommon
                 RTSanitizerCommonLibc
add_custom_target(GotsanRuntimeCheck
     DEPENDS tsan ${BUILDGO_SCRIPT}
     WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/go
     COMMENT "Checking TSan Go runtime..."
     VERBATIM)
 else()
   foreach(arch ${TSAN_SUPPORTED_ARCH})
     if(arch STREQUAL "x86_64")
       set(TSAN_ASM_SOURCES rtl/tsan_rtl_amd64.S)
-      # Pass ASM file directly to the C++ compiler.
-      set_source_files_properties(${TSAN_ASM_SOURCES} PROPERTIES
-        LANGUAGE C)
       # Sanity check for Go runtime.
       set(BUILDGO_SCRIPT ${CMAKE_CURRENT_SOURCE_DIR}/go/buildgo.sh)
       add_custom_target(GotsanRuntimeCheck
         COMMAND env "CC=${CMAKE_C_COMPILER} ${CMAKE_C_COMPILER_ARG1}"
                 IN_TMPDIR=1 SILENT=1 ${BUILDGO_SCRIPT}
         DEPENDS clang_rt.tsan-${arch} ${BUILDGO_SCRIPT}
         WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/go
         COMMENT "Checking TSan Go runtime..."
         VERBATIM)
     elseif(arch STREQUAL "aarch64")
       set(TSAN_ASM_SOURCES rtl/tsan_rtl_aarch64.S)
-      # Pass ASM file directly to the C++ compiler.
-      set_source_files_properties(${TSAN_ASM_SOURCES} PROPERTIES
-        LANGUAGE C)
    elseif(arch MATCHES "powerpc64|powerpc64le")
      set(TSAN_ASM_SOURCES rtl/tsan_rtl_ppc64.S)
-     # Pass ASM file directly to the C++ compiler.
-     set_source_files_properties(${TSAN_ASM_SOURCES} PROPERTIES
-       LANGUAGE C)
     elseif(arch MATCHES "mips64|mips64le")
      set(TSAN_ASM_SOURCES rtl/tsan_rtl_mips64.S)
-     # Pass ASM file directly to the C++ compiler.
-     set_source_files_properties(${TSAN_ASM_SOURCES} PROPERTIES
-       LANGUAGE C)
     else()
       set(TSAN_ASM_SOURCES)
     endif()
     add_compiler_rt_runtime(clang_rt.tsan
       STATIC
       ARCHS ${arch}
       SOURCES ${TSAN_SOURCES} ${TSAN_ASM_SOURCES}
               $<TARGET_OBJECTS:RTInterception.${arch}>