Re-apply "Fix cmake check for futimens when deploying to earlier macOS releases."

This fixes an issue with the use of LLVM_PARALLEL_LINK_JOBS.

Original commit message:
macOS 10.13 added a new API (futimens). This API is only available on macOS 10.13
and later, but the cmake check we have in place only tests if the symbol is
present and ignores the availability attribute. Luckily we have new warning for
this and by making this warning an error the cmake check will return the correct
result.

See also rdar://problem/33992750.

Differential Revision: https://reviews.llvm.org/D37027

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@311965 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/cmake/config-ix.cmake b/cmake/config-ix.cmake
index f777b9c1c144f2181037ba287e6f6c042f8b86a5..a1a16b99eb1a400b545ecda638fe624405dba56d 100644 (file)
--- a/cmake/config-ix.cmake
+++ b/cmake/config-ix.cmake
@@ -8,6 +8,7 @@ include(CheckIncludeFileCXX)
 include(CheckLibraryExists)
 include(CheckSymbolExists)
 include(CheckFunctionExists)
+include(CheckCCompilerFlag)
 include(CheckCXXSourceCompiles)
 include(TestBigEndian)
 
@@ -179,6 +180,14 @@ check_symbol_exists(arc4random "stdlib.h" HAVE_DECL_ARC4RANDOM)
 find_package(Backtrace)
 set(HAVE_BACKTRACE ${Backtrace_FOUND})
 set(BACKTRACE_HEADER ${Backtrace_HEADER})
+
+# Prevent check_symbol_exists from using API that is not supported for a given
+# deployment target.
+check_c_compiler_flag("-Werror=unguarded-availability-new" "C_SUPPORTS_WERROR_UNGUARDED_AVAILABILITY_NEW")
+if(C_SUPPORTS_WERROR_UNGUARDED_AVAILABILITY_NEW)
+  set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -Werror=unguarded-availability-new")
+endif()
+
 check_symbol_exists(_Unwind_Backtrace "unwind.h" HAVE__UNWIND_BACKTRACE)
 check_symbol_exists(getpagesize unistd.h HAVE_GETPAGESIZE)
 check_symbol_exists(sysconf unistd.h HAVE_SYSCONF)

diff --git a/cmake/modules/HandleLLVMOptions.cmake b/cmake/modules/HandleLLVMOptions.cmake
index 04596a6ff63f58b93f556af2b07d1c3e3483a167..a2ab12838083df3adbc580fc82b69075ae3aa074 100644 (file)
--- a/cmake/modules/HandleLLVMOptions.cmake
+++ b/cmake/modules/HandleLLVMOptions.cmake
@@ -383,6 +383,7 @@ elseif( LLVM_COMPILER_IS_GCC_COMPATIBLE )
   append_if(LLVM_ENABLE_WERROR "-Werror" CMAKE_C_FLAGS CMAKE_CXX_FLAGS)
   append_if(LLVM_ENABLE_WERROR "-Wno-error" CMAKE_REQUIRED_FLAGS)
   add_flag_if_supported("-Werror=date-time" WERROR_DATE_TIME)
+  add_flag_if_supported("-Werror=unguarded-availability-new" WERROR_UNGUARDED_AVAILABILITY_NEW)
   if (LLVM_ENABLE_CXX1Y)
     check_cxx_compiler_flag("-std=c++1y" CXX_SUPPORTS_CXX1Y)
     append_if(CXX_SUPPORTS_CXX1Y "-std=c++1y" CMAKE_CXX_FLAGS)