From 4b5dbaa96a6e51e925ac017468538754aad8e5cc Mon Sep 17 00:00:00 2001
From: Edwin Vane <edwin.vane@intel.com>
Date: Mon, 4 Feb 2013 02:32:44 +0000
Subject: 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
---
 cmake/config-ix.cmake                 | 18 ++++++++++++++++++
 cmake/modules/HandleLLVMOptions.cmake |  6 ++++++
 2 files changed, 24 insertions(+)

(limited to 'cmake')

diff --git a/cmake/config-ix.cmake b/cmake/config-ix.cmake
index a313e9cbb0..b079a0738b 100755
--- 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 3cf1ef20e4..91210804c3 100644
--- 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 )
-- 
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