[compiler-rt] Fix library suffixes on windows

[fjricci]

Summary

Make sure that windows libraries contain the suffixes expected by clang.
This is expecially important when compiling the windows builtins with
clang, as cmake will use .a as the suffix by default.

[beanz]

I question if this is correct. When targeting Windows CMAKE_STATIC_LIBRARY_SUFFIX should be ".lib" by default, unless you're targeting MinGW or Cygwin, in which case it is ".a".

Is this not what you're experiencing?

[fjricci]

The problem comes when we use clang and not MSVC, and the gcc driver in clang is used, which adds the .a suffix instead of the .lib suffix by default.

(cmake:Modules/Platform/Windows-Clang.cmake)

if("x${CMAKE_C_SIMULATE_ID}" STREQUAL "xMSVC"
    OR "x${CMAKE_CXX_SIMULATE_ID}" STREQUAL "xMSVC")
  include(Platform/Windows-MSVC)
  macro(__windows_compiler_clang lang)
    __windows_compiler_msvc(${lang})
  endmacro()
else()
  include(Platform/Windows-GNU)
  macro(__windows_compiler_clang lang)
    __windows_compiler_gnu(${lang})
  endmacro()
endif()

I'll update the patch to check for CMAKE_SYSTEM_NAME=Windows instead of WIN32 to avoid breaking MinGW and Cygwin.

[fjricci]

Make sure suffixes aren't changed on MinGW or Cygwin

[fjricci]

Also make sure correct prefixes are used, and fix mingw/cygwin checks

[fjricci]

Make sure to also set prefix for import libraries

[fjricci]

I sent a message to the cmake developer list to ask about using the correct suffixes by default when using the GNU driver in clang to target MSVCRT. For now, I'll go ahead and merge this patch, and hope that we can remove it if cmake adds proper support in the future.

compiler-rt/trunk/cmake/Modules/AddCompilerRT.cmake

foreach(libname ${libnames})
     set_target_compile_flags(${libname} ${extra_cflags_${libname}})
     set_target_link_flags(${libname} ${extra_linkflags_${libname}})
     set_property(TARGET ${libname} APPEND PROPERTY
                 COMPILE_DEFINITIONS ${LIB_DEFS})
     set_target_output_directories(${libname} ${COMPILER_RT_LIBRARY_OUTPUT_DIR})
     set_target_properties(${libname} PROPERTIES
         OUTPUT_NAME ${output_name_${libname}})
     set_target_properties(${libname} PROPERTIES FOLDER "Compiler-RT Runtime")
-    if(LIB_LINK_LIBS AND ${type} STREQUAL "SHARED")
+    if(${type} STREQUAL "SHARED")
+      if(LIB_LINK_LIBS)
         target_link_libraries(${libname} ${LIB_LINK_LIBS})
       endif()
+      if(WIN32 AND NOT CYGWIN AND NOT MINGW)
+        set_target_properties(${libname} PROPERTIES IMPORT_PREFIX "")
+        set_target_properties(${libname} PROPERTIES IMPORT_SUFFIX ".lib")
+      endif()
+    endif()
     install(TARGETS ${libname}
       ARCHIVE DESTINATION ${COMPILER_RT_LIBRARY_INSTALL_DIR}
               ${COMPONENT_OPTION}
       LIBRARY DESTINATION ${COMPILER_RT_LIBRARY_INSTALL_DIR}
               ${COMPONENT_OPTION}
       RUNTIME DESTINATION ${COMPILER_RT_LIBRARY_INSTALL_DIR}
               ${COMPONENT_OPTION})
 

compiler-rt/trunk/cmake/base-config-ix.cmake

if(NOT EXISTS /usr/include)
     set(OSX_SYSROOT_FLAG "-isysroot${OSX_SYSROOT}")
   endif()
 
   option(COMPILER_RT_ENABLE_IOS "Enable building for iOS" Off)
   option(COMPILER_RT_ENABLE_WATCHOS "Enable building for watchOS - Experimental" Off)
   option(COMPILER_RT_ENABLE_TVOS "Enable building for tvOS - Experimental" Off)
 endif()
 
+if(WIN32 AND NOT MINGW AND NOT CYGWIN)
+  set(CMAKE_SHARED_LIBRARY_PREFIX_C "")
+  set(CMAKE_SHARED_LIBRARY_PREFIX_CXX "")
+  set(CMAKE_STATIC_LIBRARY_PREFIX_C "")
+  set(CMAKE_STATIC_LIBRARY_PREFIX_CXX "")
+  set(CMAKE_STATIC_LIBRARY_SUFFIX_C ".lib")
+  set(CMAKE_STATIC_LIBRARY_SUFFIX_CXX ".lib")
+endif()
+
 macro(test_targets)
   # Find and run MSVC (not clang-cl) and get its version. This will tell clang-cl
   # what version of MSVC to pretend to be so that the STL works.
   set(MSVC_VERSION_FLAG "")
   if (MSVC)
     # Find and run MSVC (not clang-cl) and get its version. This will tell
     # clang-cl what version of MSVC to pretend to be so that the STL works.
     execute_process(COMMAND "$ENV{VSINSTALLDIR}/VC/bin/cl.exe"