[PATCH] D72335: [CMake] Enable -qfuncsect when building with IBM XL

[Hubert Tong via Phabricator via llvm-commits]

hubert.reinterpretcast created this revision.
hubert.reinterpretcast added reviewers: daltenty, stevewan.
Herald added subscribers: Sanitizers, steven.zhang, mgorny.
Herald added projects: Sanitizers, LLVM.

The IBM XL compiler uses `-qfuncsect` for `-ffunction-sections`.

The comment about sanitizers and `-f[no-]function-sections` is corrected also, as it is pertinent to this patch.

The sanitizer-related use of `-fno-function-sections` is associated with powerpc64le, a target for which there is an IBM XL compiler, so that use is updated in this patch to apply `-qnofuncsect` in case a build using the XL compiler is viable on that platform.

This patch has been verified with the XL compiler on AIX only.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D72335

Files:
  compiler-rt/CMakeLists.txt
  llvm/cmake/modules/HandleLLVMOptions.cmake


Index: llvm/cmake/modules/HandleLLVMOptions.cmake
===================================================================
--- llvm/cmake/modules/HandleLLVMOptions.cmake
+++ llvm/cmake/modules/HandleLLVMOptions.cmake
@@ -782,9 +782,11 @@
      NOT uppercase_CMAKE_BUILD_TYPE STREQUAL "DEBUG")
     check_c_compiler_flag("-Werror -fno-function-sections" C_SUPPORTS_FNO_FUNCTION_SECTIONS)
     if (C_SUPPORTS_FNO_FUNCTION_SECTIONS)
-      # Don't add -ffunction-section if it can be disabled with -fno-function-sections.
+      # Don't add -ffunction-sections if it can't be disabled with -fno-function-sections.
       # Doing so will break sanitizers.
       add_flag_if_supported("-ffunction-sections" FFUNCTION_SECTIONS)
+    elseif (CMAKE_CXX_COMPILER_ID MATCHES "XL")
+      append("-qfuncsect" CMAKE_C_FLAGS CMAKE_CXX_FLAGS)
     endif()
     add_flag_if_supported("-fdata-sections" FDATA_SECTIONS)
   endif()
Index: compiler-rt/CMakeLists.txt
===================================================================
--- compiler-rt/CMakeLists.txt
+++ compiler-rt/CMakeLists.txt
@@ -286,7 +286,11 @@
 # Linux test function-sections-are-bad.cpp fails with the following error:
 # 'undefined symbol: __sanitizer_unaligned_load32'.
 if(DEFINED TARGET_powerpc64le_CFLAGS)
-  append_list_if(COMPILER_RT_HAS_FNO_FUNCTION_SECTIONS_FLAG -fno-function-sections TARGET_powerpc64le_CFLAGS)
+  if(CMAKE_CXX_COMPILER_ID MATCHES "XL")
+    append("-qnofuncsect" TARGET_powerpc64le_CFLAGS)
+  else()
+    append_list_if(COMPILER_RT_HAS_FNO_FUNCTION_SECTIONS_FLAG -fno-function-sections TARGET_powerpc64le_CFLAGS)
+  endif()
 endif()
 
 # The following is a workaround for s390x.  This avoids creation of "partial


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