[cmake] By default do not instrument compiler-rt if LLVM_BUILD_INSTRUMENTED_COVERAGE is ON

[djtodoro]

Summary

I wasn't able to build all the LLVM projects when LLVM_BUILD_INSTRUMENTED_COVERAGE is set to ON since the compiler is finding some issues with unresolved symbols inside compiler-rt. If the compiler-rt isn't meant to be built with LLVM_BUILD_INSTRUMENTED_COVERAGE by default, I think that something like this makes sense.

[djtodoro]

Ping :)

[vsk]

compiler-rt/CMakeLists.txt

317–320

It looks like support for what you're trying to do might already exist. Could you share more context on COMPILER_RT_HAS_FNO_PROFILE_INSTR_GENERATE_FLAG & COMPILER_RT_ENABLE_PGO, and why these are/aren't applicable for your workflow?

[djtodoro]

compiler-rt/CMakeLists.txt

317–320

Basically, I am facing similar problems as described in the D75499. That patch disabled PGO related flags for compiler-rt, but it applies to the LLVM_BUILD_INSTRUMENTED option only.
There is another instrumentation option LLVM_BUILD_INSTRUMENTED_COVERAGE (we cannot specify both LLVM_BUILD_INSTRUMENTED and LLVM_BUILD_INSTRUMENTED_COVERAGE) that includes -fcoverage-mapping in addition to -fprofile-instr-generate. I was wondering if we should do the same for this CMAKE option (I definitely need to add something like COMPILER_RT_HAS_FNO_CIVERAGE_MAPPING_FLAG, and to cover all other spots in CMake files, etc).

[djtodoro]

• follow the LLVM_BUILD_INSTRUMENTED approach of disabling PGO flags

[djtodoro]

• nit: fixing an elsif()

[djtodoro]

ping :)

[djtodoro]

ping :)

[djtodoro]

Ping. :)

This is very similar to D75499. The patch disabled PGO related flags for compiler-rt in the case of LLVM_BUILD_INSTRUMENTED.
There is another instrumentation option LLVM_BUILD_INSTRUMENTED_COVERAGE which should have been addressed as well.

[vitalybuka]

In D108127#3074461, @djtodoro wrote:

Ping. :)

This is very similar to D75499. The patch disabled PGO related flags for compiler-rt in the case of LLVM_BUILD_INSTRUMENTED.
There is another instrumentation option LLVM_BUILD_INSTRUMENTED_COVERAGE which should have been addressed as well.

Does @xur have an opinion on this? I don't have one here.
Maybe @petrhosek @MaskRay ?

[MaskRay]

Can you combine the conditions? Maybe looks like:

(LLVM_BUILD_INSTRUMENTED OR LLVM_BUILD_INSTRUMENTED_COVERAGE) AND COMPILER_RT_HAS_FNO_PROFILE_INSTR_GENERATE_FLAG

[djtodoro]

In D108127#3110772, @MaskRay wrote:

Can you combine the conditions? Maybe looks like:

(LLVM_BUILD_INSTRUMENTED OR LLVM_BUILD_INSTRUMENTED_COVERAGE) AND COMPILER_RT_HAS_FNO_PROFILE_INSTR_GENERATE_FLAG

@MaskRay thanks for your comment, it makes sense to me.

[djtodoro]

• addressing the comment

[MaskRay]

Thanks!

compiler-rt/CMakeLists.txt

 
 # By default do not instrument or use profdata for compiler-rt.
 if(NOT COMPILER_RT_ENABLE_PGO)
   if(LLVM_PROFDATA_FILE AND COMPILER_RT_HAS_FNO_PROFILE_INSTR_USE_FLAG)
     list(APPEND SANITIZER_COMMON_CFLAGS "-fno-profile-instr-use")
   endif()
   if(LLVM_BUILD_INSTRUMENTED MATCHES IR AND COMPILER_RT_HAS_FNO_PROFILE_GENERATE_FLAG)
     list(APPEND SANITIZER_COMMON_CFLAGS "-fno-profile-generate")
-  elseif(LLVM_BUILD_INSTRUMENTED AND COMPILER_RT_HAS_FNO_PROFILE_INSTR_GENERATE_FLAG)
+  elseif((LLVM_BUILD_INSTRUMENTED OR LLVM_BUILD_INSTRUMENTED_COVERAGE) AND COMPILER_RT_HAS_FNO_PROFILE_INSTR_GENERATE_FLAG)
     list(APPEND SANITIZER_COMMON_CFLAGS "-fno-profile-instr-generate")
+    if(LLVM_BUILD_INSTRUMENTED_COVERAGE AND COMPILER_RT_HAS_FNO_COVERAGE_MAPPING_FLAG)
+      list(APPEND SANITIZER_COMMON_CFLAGS "-fno-coverage-mapping")
+    endif()
   endif()
 endif()
 
 # The following is a workaround for powerpc64le. This is the only architecture
 # that requires -fno-function-sections to work properly. If lacking, the ASan
 # Linux test function-sections-are-bad.cpp fails with the following error:
 # 'undefined symbol: __sanitizer_unaligned_load32'.
 if(DEFINED TARGET_powerpc64le_CFLAGS)

compiler-rt/cmake/Modules/AddCompilerRT.cmake

function(add_compiler_rt_runtime name type)
   # By default do not instrument or use profdata for compiler-rt.
   set(NO_PGO_FLAGS "")
   if(NOT COMPILER_RT_ENABLE_PGO)
     if(LLVM_PROFDATA_FILE AND COMPILER_RT_HAS_FNO_PROFILE_INSTR_USE_FLAG)
       list(APPEND NO_PGO_FLAGS "-fno-profile-instr-use")
     endif()
     if(LLVM_BUILD_INSTRUMENTED MATCHES IR AND COMPILER_RT_HAS_FNO_PROFILE_GENERATE_FLAG)
       list(APPEND NO_PGO_FLAGS "-fno-profile-generate")
-    elseif(LLVM_BUILD_INSTRUMENTED AND COMPILER_RT_HAS_FNO_PROFILE_INSTR_GENERATE_FLAG)
+    elseif((LLVM_BUILD_INSTRUMENTED OR LLVM_BUILD_INSTRUMENTED_COVERAGE) AND COMPILER_RT_HAS_FNO_PROFILE_INSTR_GENERATE_FLAG)
       list(APPEND NO_PGO_FLAGS "-fno-profile-instr-generate")
+      if(LLVM_BUILD_INSTRUMENTED_COVERAGE AND COMPILER_RT_HAS_FNO_COVERAGE_MAPPING_FLAG)
+        list(APPEND NO_PGO_FLAGS "-fno-coverage-mapping")
+      endif()
     endif()
   endif()
 
   list(LENGTH LIB_SOURCES LIB_SOURCES_LENGTH)
   if (${LIB_SOURCES_LENGTH} GREATER 0)
     # Add headers to LIB_SOURCES for IDEs. It doesn't make sense to
     # do this for a runtime library that only consists of OBJECT
     # libraries, so only add the headers when source files are present.

compiler-rt/cmake/config-ix.cmake

 check_cxx_compiler_flag(-fno-rtti            COMPILER_RT_HAS_FNO_RTTI_FLAG)
 check_cxx_compiler_flag("-Werror -fno-function-sections" COMPILER_RT_HAS_FNO_FUNCTION_SECTIONS_FLAG)
 check_cxx_compiler_flag(-std=c++14           COMPILER_RT_HAS_STD_CXX14_FLAG)
 check_cxx_compiler_flag(-ftls-model=initial-exec COMPILER_RT_HAS_FTLS_MODEL_INITIAL_EXEC)
 check_cxx_compiler_flag(-fno-lto             COMPILER_RT_HAS_FNO_LTO_FLAG)
 check_cxx_compiler_flag(-fno-profile-generate COMPILER_RT_HAS_FNO_PROFILE_GENERATE_FLAG)
 check_cxx_compiler_flag(-fno-profile-instr-generate COMPILER_RT_HAS_FNO_PROFILE_INSTR_GENERATE_FLAG)
 check_cxx_compiler_flag(-fno-profile-instr-use COMPILER_RT_HAS_FNO_PROFILE_INSTR_USE_FLAG)
+check_cxx_compiler_flag(-fno-coverage-mapping COMPILER_RT_HAS_FNO_COVERAGE_MAPPING_FLAG)
 check_cxx_compiler_flag("-Werror -msse3" COMPILER_RT_HAS_MSSE3_FLAG)
 check_cxx_compiler_flag("-Werror -msse4.2"   COMPILER_RT_HAS_MSSE4_2_FLAG)
 check_cxx_compiler_flag(--sysroot=.          COMPILER_RT_HAS_SYSROOT_FLAG)
 check_cxx_compiler_flag("-Werror -mcrc"      COMPILER_RT_HAS_MCRC_FLAG)
 check_cxx_compiler_flag(-fno-partial-inlining COMPILER_RT_HAS_FNO_PARTIAL_INLINING_FLAG)
 
 if(NOT WIN32 AND NOT CYGWIN)
   # MinGW warns if -fvisibility-inlines-hidden is used.

compiler-rt/lib/crt/CMakeLists.txt

function(check_cxx_section_exists section output)
   endif()
   append_list_if(COMPILER_RT_HAS_FNO_LTO_FLAG -fno-lto try_compile_flags)
   if(NOT COMPILER_RT_ENABLE_PGO)
     if(LLVM_PROFDATA_FILE AND COMPILER_RT_HAS_FNO_PROFILE_INSTR_USE_FLAG)
       list(APPEND try_compile_flags "-fno-profile-instr-use")
     endif()
     if(LLVM_BUILD_INSTRUMENTED MATCHES IR AND COMPILER_RT_HAS_FNO_PROFILE_GENERATE_FLAG)
       list(APPEND try_compile_flags "-fno-profile-generate")
-    elseif(LLVM_BUILD_INSTRUMENTED AND COMPILER_RT_HAS_FNO_PROFILE_INSTR_GENERATE_FLAG)
+    elseif((LLVM_BUILD_INSTRUMENTED OR LLVM_BUILD_INSTRUMENTED_COVERAGE) AND COMPILER_RT_HAS_FNO_PROFILE_INSTR_GENERATE_FLAG)
       list(APPEND try_compile_flags "-fno-profile-instr-generate")
+      if(LLVM_BUILD_INSTRUMENTED_COVERAGE AND COMPILER_RT_HAS_FNO_COVERAGE_MAPPING_FLAG)
+        list(APPEND try_compile_flags "-fno-coverage-mapping")
+      endif()
     endif()
   endif()
 
   string(REPLACE ";" " " extra_flags "${try_compile_flags}")
 
   set(test_compile_command "${CMAKE_C_COMPILE_OBJECT}")
   foreach(substitution ${substitutions})
     if(substitution STREQUAL "<CMAKE_C_COMPILER>")