[CMake] Add -stdlib=libc++ to host Clang build flags before performing any header...

If LLVM_ENABLE_LIBCXX is specified, we should append -stdlib=libc++ to build
flags as early as possible, in particular, before we check for header presence
(as -stdlib=libc++ modifies header lookup rules). Otherwise we can find a header
at configure time (w/o -stdlib=libc++) but fail to find it at build time
(with -stdlib=libc++). See PR18569 for more details.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200744 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 122c47d4a81ffe1262214108a2461afcab5c99b4..e7275600bc2999c3337e0cfd629f1ce4756ee364 100644 (file)
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -272,6 +272,14 @@ option (LLVM_BUILD_DOCS "Build the llvm documentation." OFF)
 option (LLVM_INCLUDE_DOCS "Generate build targets for llvm documentation." ON)
 option (LLVM_ENABLE_DOXYGEN "Use doxygen to generate llvm documentation." OFF)
 
+if( CMAKE_COMPILER_IS_GNUCXX )
+  set(LLVM_COMPILER_IS_GCC_COMPATIBLE ON)
+elseif( MSVC )
+  set(LLVM_COMPILER_IS_GCC_COMPATIBLE OFF)
+elseif( "${CMAKE_CXX_COMPILER_ID}" MATCHES "Clang" )
+  set(LLVM_COMPILER_IS_GCC_COMPATIBLE ON)
+endif()
+
 # All options referred to from HandleLLVMOptions have to be specified
 # BEFORE this include, otherwise options will not be correctly set on
 # first cmake run

diff --git a/cmake/config-ix.cmake b/cmake/config-ix.cmake
index c8a857108983451183b7c115547c9e1afd2b9554..c9a5044099417c0d2489c9e97d56ef7388114084 100755 (executable)
--- a/cmake/config-ix.cmake
+++ b/cmake/config-ix.cmake
@@ -34,6 +34,25 @@ function(check_type_exists type files variable)
     " ${variable})
 endfunction()
 
+function(append_if condition value)
+  if (${condition})
+    foreach(variable ${ARGN})
+      set(${variable} "${${variable}} ${value}" PARENT_SCOPE)
+    endforeach(variable)
+  endif()
+endfunction()
+
+include(CheckCXXCompilerFlag)
+if( LLVM_COMPILER_IS_GCC_COMPATIBLE )
+  if( LLVM_ENABLE_LIBCXX )
+    check_cxx_compiler_flag("-stdlib=libc++" CXX_SUPPORTS_STDLIB)
+    append_if(CXX_SUPPORTS_STDLIB "-stdlib=libc++" CMAKE_CXX_FLAGS)
+    append_if(CXX_SUPPORTS_STDLIB "-stdlib=libc++" CMAKE_EXE_LINKER_FLAGS)
+    append_if(CXX_SUPPORTS_STDLIB "-stdlib=libc++" CMAKE_SHARED_LINKER_FLAGS)
+    append_if(CXX_SUPPORTS_STDLIB "-stdlib=libc++" CMAKE_MODULE_LINKER_FLAGS)
+  endif()
+endif()
+
 # include checks
 check_include_file_cxx(cxxabi.h HAVE_CXXABI_H)
 check_include_file(dirent.h HAVE_DIRENT_H)
@@ -317,8 +336,6 @@ if (LIBXML2_FOUND)
   endif ()
 endif ()
 
-include(CheckCXXCompilerFlag)
-
 check_cxx_compiler_flag("-Wno-variadic-macros" SUPPORTS_NO_VARIADIC_MACROS_FLAG)
 
 set(USE_NO_MAYBE_UNINITIALIZED 0)

diff --git a/cmake/modules/HandleLLVMOptions.cmake b/cmake/modules/HandleLLVMOptions.cmake
index 38bbd2ea7e10aabff58e358e8c69b96ce7f249aa..8e4b6bbdafd36bf811ac796d49695a1b9a94e49d 100644 (file)
--- a/cmake/modules/HandleLLVMOptions.cmake
+++ b/cmake/modules/HandleLLVMOptions.cmake
@@ -6,14 +6,6 @@ include(AddLLVMDefinitions)
 include(CheckCCompilerFlag)
 include(CheckCXXCompilerFlag)
 
-if( CMAKE_COMPILER_IS_GNUCXX )
-  set(LLVM_COMPILER_IS_GCC_COMPATIBLE ON)
-elseif( MSVC )
-  set(LLVM_COMPILER_IS_GCC_COMPATIBLE OFF)
-elseif( "${CMAKE_CXX_COMPILER_ID}" MATCHES "Clang" )
-  set(LLVM_COMPILER_IS_GCC_COMPATIBLE ON)
-endif()
-
 if(NOT LLVM_FORCE_USE_OLD_TOOLCHAIN)
   if(CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
     if(CMAKE_CXX_COMPILER_VERSION VERSION_LESS 4.7)
@@ -291,13 +283,6 @@ elseif( LLVM_COMPILER_IS_GCC_COMPATIBLE )
     check_cxx_compiler_flag("-std=c++11" CXX_SUPPORTS_CXX11)
     append_if(CXX_SUPPORTS_CXX11 "-std=c++11" CMAKE_CXX_FLAGS)
   endif (LLVM_ENABLE_CXX11)
-  if(LLVM_ENABLE_LIBCXX)
-    check_cxx_compiler_flag("-stdlib=libc++" CXX_SUPPORTS_STDLIB)
-    append_if(CXX_SUPPORTS_STDLIB "-stdlib=libc++" CMAKE_CXX_FLAGS)
-    append_if(CXX_SUPPORTS_STDLIB "-stdlib=libc++" CMAKE_EXE_LINKER_FLAGS)
-    append_if(CXX_SUPPORTS_STDLIB "-stdlib=libc++" CMAKE_SHARED_LINKER_FLAGS)
-    append_if(CXX_SUPPORTS_STDLIB "-stdlib=libc++" CMAKE_MODULE_LINKER_FLAGS)
-  endif ()
 endif( MSVC )
 
 macro(append_common_sanitizer_flags)