[llvm] r311965 - Re-apply "Fix cmake check for futimens when deploying to earlier macOS releases."

[Juergen Ributzka via llvm-commits]

Author: ributzka
Date: Mon Aug 28 17:34:56 2017
New Revision: 311965

URL: http://llvm.org/viewvc/llvm-project?rev=311965&view=rev
Log:
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

Modified:
    llvm/trunk/cmake/config-ix.cmake
    llvm/trunk/cmake/modules/HandleLLVMOptions.cmake

Modified: llvm/trunk/cmake/config-ix.cmake
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/cmake/config-ix.cmake?rev=311965&r1=311964&r2=311965&view=diff
==============================================================================
--- llvm/trunk/cmake/config-ix.cmake (original)
+++ llvm/trunk/cmake/config-ix.cmake Mon Aug 28 17:34:56 2017
@@ -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
 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)

Modified: llvm/trunk/cmake/modules/HandleLLVMOptions.cmake
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/cmake/modules/HandleLLVMOptions.cmake?rev=311965&r1=311964&r2=311965&view=diff
==============================================================================
--- llvm/trunk/cmake/modules/HandleLLVMOptions.cmake (original)
+++ llvm/trunk/cmake/modules/HandleLLVMOptions.cmake Mon Aug 28 17:34:56 2017
@@ -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)