Fix llvm-shlib cmake build

[vchuravy]

Summary

This fixes a few things that used to work with a Makefile build, but were broken in cmake.

1. Treat MINGW like a Linux system.
2. The shlib should never contain other shared libraries.

[axw]

Couple of little things, LGTM otherwise.

tools/llvm-shlib/CMakeLists.txt

10–11

if(LLVM_LINK_LLVM_DYLIB AND LLVM_DYLIB_EXPORTED_SYMBOL_FILE)
?

11

LLVM_BUILD_LLVM_DYLIB is implied by this file being processed, so just make this unconditional?

[vchuravy]

Address review comments

[beanz]

LGTM!

[vchuravy]

Since I am new to LLVM I was wondering what the process of landing this is?

[beanz]

I have landed your patch in rL285737.

Thank you for your contribution!

-Chris

tools/llvm-shlib/CMakeLists.txt

 # This tool creates a shared library from the LLVM libraries. Generating this
 # library is enabled by setting LLVM_BUILD_LLVM_DYLIB=yes on the CMake
 # commandline. By default the shared library only exports the LLVM C API.
 
 set(SOURCES
   libllvm.cpp
   )
 
 llvm_map_components_to_libnames(LIB_NAMES ${LLVM_DYLIB_COMPONENTS})
 
-if(LLVM_LINK_LLVM_DYLIB)
-  if(LLVM_DYLIB_EXPORTED_SYMBOL_FILE)
-    message(WARNING "Using LLVM_LINK_LLVM_DYLIB with LLVM_DYLIB_EXPORTED_SYMBOL_FILE may not work. Use at your own risk.")
-  endif()
+if(LLVM_LINK_LLVM_DYLIB AND LLVM_DYLIB_EXPORTED_SYMBOL_FILE)
 
-  # libLLVM.so should not have any dependencies on any other LLVM
-  # shared libraries. When using the "all" pseudo-component,
-  # LLVM_AVAILABLE_LIBS is added to the dependencies, which may
-  # contain shared libraries (e.g. libLTO).
-  #
-  # Also exclude libLLVMTableGen for the following reasons:
-  #  - it is only used by internal *-tblgen utilities;
-  #  - it pollutes the global options space.
-  foreach(lib ${LIB_NAMES})
-    get_target_property(t ${lib} TYPE)
-    if("${lib}" STREQUAL "LLVMTableGen")
-    elseif("x${t}" STREQUAL "xSTATIC_LIBRARY")
-      list(APPEND FILTERED_LIB_NAMES ${lib})
-    endif()
-  endforeach()
-  set(LIB_NAMES ${FILTERED_LIB_NAMES})
-endif()
 
 if(LLVM_DYLIB_EXPORTED_SYMBOL_FILE)
   set(LLVM_EXPORTED_SYMBOL_FILE ${LLVM_DYLIB_EXPORTED_SYMBOL_FILE})
   add_custom_target(libLLVMExports DEPENDS ${LLVM_EXPORTED_SYMBOL_FILE})
 endif()
 
 add_llvm_library(LLVM SHARED DISABLE_LLVM_LINK_LLVM_DYLIB SONAME ${SOURCES})
 
 list(REMOVE_DUPLICATES LIB_NAMES)
-if("${CMAKE_SYSTEM_NAME}" STREQUAL "Linux") # FIXME: It should be "GNU ld for elf"
+if("${CMAKE_SYSTEM_NAME}" STREQUAL "Linux" OR MINGW) # FIXME: It should be "GNU ld for elf"
   # GNU ld doesn't resolve symbols in the version script.
   set(LIB_NAMES -Wl,--whole-archive ${LIB_NAMES} -Wl,--no-whole-archive)
 elseif("${CMAKE_SYSTEM_NAME}" STREQUAL "Darwin")
   set(LIB_NAMES -Wl,-all_load ${LIB_NAMES})
 endif()
 
 target_link_libraries(LLVM PRIVATE ${LIB_NAMES})