Turn off uninitialized-use warnings for gcc in cmake build

Added support to the cmake build to turn off uninitialized use warnings
for gcc. This cleans the build up somewhat.

Used logic simpler than found in autoconf by making use of the fact that
although gcc won't complain about unsupported -Wno-* flags it *will*
complain about unsupported -W flags.

Reviewers: gribozavr, doug.gregor, chandlerc

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@174299 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/cmake/config-ix.cmake b/cmake/config-ix.cmake
index a313e9cbb03ecca81ecb664d697072a4984542ff..b079a0738b911099d6e791beeeb7c6c29fdbc4d8 100755 (executable)
--- a/cmake/config-ix.cmake
+++ b/cmake/config-ix.cmake
@@ -305,6 +305,24 @@ include(CheckCXXCompilerFlag)
 
 check_cxx_compiler_flag("-Wno-variadic-macros" SUPPORTS_NO_VARIADIC_MACROS_FLAG)
 
+set(USE_NO_MAYBE_UNINITIALIZED 0)
+set(USE_NO_UNINITIALIZED 0)
+
+# Disable gcc's potentially uninitialized use analysis as it presents lots of
+# false positives.
+if (CMAKE_COMPILER_IS_GNUCXX)
+  check_cxx_compiler_flag("-Wmaybe-uninitialized" HAS_MAYBE_UNINITIALIZED)
+  if (HAS_MAYBE_UNINITIALIZED)
+    set(USE_NO_MAYBE_UNINITIALIZED 1)
+  else()
+    # Only recent versions of gcc make the distinction between -Wuninitialized
+    # and -Wmaybe-uninitialized. If -Wmaybe-uninitialized isn't supported, just
+    # turn off all uninitialized use warnings.
+    check_cxx_compiler_flag("-Wuninitialized" HAS_UNINITIALIZED)
+    set(USE_NO_UNINITIALIZED ${HAS_UNINITIALIZED})
+  endif()
+endif()
+
 include(GetHostTriple)
 get_host_triple(LLVM_HOST_TRIPLE)
 

diff --git a/cmake/modules/HandleLLVMOptions.cmake b/cmake/modules/HandleLLVMOptions.cmake
index 3cf1ef20e419da8f94198b636941903da7f386d0..91210804c388b197fa2ca578667b14fffa4dfa58 100644 (file)
--- a/cmake/modules/HandleLLVMOptions.cmake
+++ b/cmake/modules/HandleLLVMOptions.cmake
@@ -206,6 +206,12 @@ elseif( LLVM_COMPILER_IS_GCC_COMPATIBLE )
     if( C_SUPPORTS_COVERED_SWITCH_DEFAULT_FLAG )
       set( CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wcovered-switch-default" )
     endif()
+    if (USE_NO_UNINITIALIZED)
+      set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-uninitialized")
+    endif()
+    if (USE_NO_MAYBE_UNINITIALIZED)
+      set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-maybe-uninitialized")
+    endif()
   endif (LLVM_ENABLE_WARNINGS)
   if (LLVM_ENABLE_WERROR)
     add_llvm_definitions( -Werror )