Compiler-RT CMake refactoring

[george.karpenkov]

Summary

Convert macro to a function, generalize the output path using CMAKE_CFG_RESOLVED_INTDIR not to require branching for multi-output build systems.

Part 2 of splitting of https://reviews.llvm.org/D36116

[vitalybuka]

Could you please put meaning full description. Patch does meaningful things on it's own.

cmake/Modules/CompilerRTCompile.cmake

45

What is the difference between CMAKE_CFG_RESOLVED_INTDIR and CMAKE_CFG_INTDIR?

[george.karpenkov]

cmake/Modules/CompilerRTCompile.cmake

45

It's a workaround for a CMake bug (https://gitlab.kitware.com/cmake/cmake/issues/17111)

Some build systems (VS) can output to multiple directories (debug/release/etc) at the same time. In those cases, there is a need for an extra output folder in the output path. In order not to guard all such usages with if CMAKE_CONFIGURATION_TYPES/else, CMake provides a CMAKE_CFG_INTDIR variable, which is resolved to "." on "normal" build systems, and to the corresponding folder on others. HOWEVER, CMake has a bug where compiling file names which start with "." (e.g. "./blah" in place of "blah") will get ignored (as the path would be resolved for the target output file, but not for the dependency list).
Thus I've created the RESOLVED version, which removes this problematic dot.

cmake/Modules/CompilerRTCompile.cmake

foreach(flag ${msvc_flags})
     endif()
   endforeach()
   set(${out_flags} "${clang_flags}" PARENT_SCOPE)
 endfunction()
 
 # Compile a sanitizer test with a freshly built clang
 # for a given architecture, adding the result to the object list.
 #  - obj_list: output list of objects, populated by path
-#              of the generated object file.
+#              of a generated object file.
 #  - source:   source file of a test.
 #  - arch:     architecture to compile for.
 # sanitizer_test_compile(<obj_list> <source> <arch>
 #                        KIND <custom namespace>
 #                        COMPILE_DEPS <list of compile-time dependencies>
 #                        DEPS <list of dependencies>
 #                        CFLAGS <list of flags>
 # )
-macro(sanitizer_test_compile obj_list source arch)
+function(sanitizer_test_compile obj_list source arch)
   cmake_parse_arguments(TEST
       "" "" "KIND;COMPILE_DEPS;DEPS;CFLAGS" ${ARGN})
   get_filename_component(basename ${source} NAME)
-  if(CMAKE_CONFIGURATION_TYPES)
-    set(output_obj
-      "${CMAKE_CFG_INTDIR}/${obj_list}.${basename}.${arch}${TEST_KIND}.o")
-  else()
-    set(output_obj "${obj_list}.${basename}.${arch}${TEST_KIND}.o")
-  endif()
+    "${CMAKE_CFG_RESOLVED_INTDIR}${obj_list}.${basename}.${arch}${TEST_KIND}.o")
 
   # Write out architecture-specific flags into TARGET_CFLAGS variable.
   get_target_flags_for_arch(${arch} TARGET_CFLAGS)
   set(COMPILE_DEPS ${TEST_COMPILE_DEPS})
   if(NOT COMPILER_RT_STANDALONE_BUILD)
     list(APPEND COMPILE_DEPS ${TEST_DEPS})
   endif()
   clang_compile(${output_obj} ${source}
                 CFLAGS ${TEST_CFLAGS} ${TARGET_CFLAGS}
                 DEPS ${TEST_COMPILE_DEPS})
   list(APPEND ${obj_list} ${output_obj})
-endmacro()
+  set("${obj_list}" "${${obj_list}}" PARENT_SCOPE)
+endfunction()
 
 # Compile a source into an object file with COMPILER_RT_TEST_COMPILER using
 # a provided compile flags and dependenices.
 # clang_compile(<object> <source>
 #               CFLAGS <list of compile flags>
 #               DEPS <list of dependencies>)
 macro(clang_compile object_file source)
   cmake_parse_arguments(SOURCE "" "" "CFLAGS;DEPS" ${ARGN})