[libunwind] r362055 - [runtimes] Check if pragma comment(lib, ...) is supported first

[Petr Hosek via cfe-commits]

Author: phosek
Date: Wed May 29 21:40:21 2019
New Revision: 362055

URL: http://llvm.org/viewvc/llvm-project?rev=362055&view=rev
Log:
[runtimes] Check if pragma comment(lib, ...) is supported first

This fixes the issue introduced by r362048 where we always use
pragma comment(lib, ...) for dependent libraries when the compiler
is Clang, but older Clang versions don't support this pragma so
we need to check first if it's supported before using it.

Modified:
    libunwind/trunk/CMakeLists.txt
    libunwind/trunk/cmake/config-ix.cmake
    libunwind/trunk/src/AddressSpace.hpp
    libunwind/trunk/src/RWMutex.hpp

Modified: libunwind/trunk/CMakeLists.txt
URL: http://llvm.org/viewvc/llvm-project/libunwind/trunk/CMakeLists.txt?rev=362055&r1=362054&r2=362055&view=diff
==============================================================================
--- libunwind/trunk/CMakeLists.txt (original)
+++ libunwind/trunk/CMakeLists.txt Wed May 29 21:40:21 2019
@@ -362,6 +362,10 @@ if (WIN32 AND LIBUNWIND_ENABLE_STATIC AN
   add_definitions(-D_LIBUNWIND_DISABLE_VISIBILITY_ANNOTATIONS)
 endif()
 
+if (LIBUNWIND_HAS_COMMENT_LIB_PRAGMA)
+  add_definitions(-D_LIBUNWIND_HAS_COMMENT_LIB_PRAGMA)
+endif()
+
 #===============================================================================
 # Setup Source Code
 #===============================================================================

Modified: libunwind/trunk/cmake/config-ix.cmake
URL: http://llvm.org/viewvc/llvm-project/libunwind/trunk/cmake/config-ix.cmake?rev=362055&r1=362054&r2=362055&view=diff
==============================================================================
--- libunwind/trunk/cmake/config-ix.cmake (original)
+++ libunwind/trunk/cmake/config-ix.cmake Wed May 29 21:40:21 2019
@@ -1,7 +1,7 @@
-
 include(CheckCCompilerFlag)
 include(CheckCXXCompilerFlag)
 include(CheckLibraryExists)
+include(CheckCSourceCompiles)
 
 check_library_exists(c fopen "" LIBUNWIND_HAS_C_LIB)
 
@@ -55,6 +55,14 @@ if (LIBUNWIND_HAS_NODEFAULTLIBS_FLAG)
   endif ()
 endif ()
 
+# Check compiler pragmas
+if(CMAKE_CXX_COMPILER_ID MATCHES "Clang")
+  check_c_source_compiles("
+#pragma comment(lib, \"c\")
+int main() { return 0; }
+" LIBUNWIND_HAS_COMMENT_LIB_PRAGMA)
+endif()
+
 # Check compiler flags
 check_c_compiler_flag(-funwind-tables         LIBUNWIND_HAS_FUNWIND_TABLES)
 check_cxx_compiler_flag(-fno-exceptions       LIBUNWIND_HAS_NO_EXCEPTIONS_FLAG)
@@ -96,4 +104,3 @@ endif()
 
 check_library_exists(dl dladdr "" LIBUNWIND_HAS_DL_LIB)
 check_library_exists(pthread pthread_once "" LIBUNWIND_HAS_PTHREAD_LIB)
-

Modified: libunwind/trunk/src/AddressSpace.hpp
URL: http://llvm.org/viewvc/llvm-project/libunwind/trunk/src/AddressSpace.hpp?rev=362055&r1=362054&r2=362055&view=diff
==============================================================================
--- libunwind/trunk/src/AddressSpace.hpp (original)
+++ libunwind/trunk/src/AddressSpace.hpp Wed May 29 21:40:21 2019
@@ -27,7 +27,7 @@
 
 #if _LIBUNWIND_USE_DLADDR
 #include <dlfcn.h>
-#if defined(__unix__) &&  defined(__ELF__) && defined(__clang__)
+#if defined(__unix__) &&  defined(__ELF__) && defined(_LIBUNWIND_HAS_COMMENT_LIB_PRAGMA)
 #pragma comment(lib, "dl")
 #endif
 #endif

Modified: libunwind/trunk/src/RWMutex.hpp
URL: http://llvm.org/viewvc/llvm-project/libunwind/trunk/src/RWMutex.hpp?rev=362055&r1=362054&r2=362055&view=diff
==============================================================================
--- libunwind/trunk/src/RWMutex.hpp (original)
+++ libunwind/trunk/src/RWMutex.hpp Wed May 29 21:40:21 2019
@@ -17,7 +17,7 @@
 #include <windows.h>
 #elif !defined(_LIBUNWIND_HAS_NO_THREADS)
 #include <pthread.h>
-#if defined(__unix__) &&  defined(__ELF__) && defined(__clang__)
+#if defined(__unix__) &&  defined(__ELF__) && defined(_LIBUNWIND_HAS_COMMENT_LIB_PRAGMA)
 #pragma comment(lib, "pthread")
 #endif
 #endif