[llvm-dev] D16945: LLVM overhaul to avoid linking LLVM component libraries with libLLVM

[Jack Howarth via llvm-dev]

Hans and Chris,
       Andrew Wilkins refactored my last patch for
http://reviews.llvm.org/D16945 into a version that properly handles
the Support library dependency of the gtest library without requiring
conditionals on LLVM_LINK_LLVM_DYLIB in
cmake/modules/LLVM-Config.cmake and utils/unittest/CMakeLists.txt. He
is awaiting a review from Chris before committing it to trunk. I have
successfully regression tested this version on the stock (static),
BUILD_SHARED_LIBS and  LLVM_LINK_LLVM_DYLIB builds of
llvm/clang/clang-tools-extra/compiler-rt/openmp/polly/libc++ on x86_64
darwin, The patch also successfully applies and regression tests on
3.8 branch so hopefully we can squeeze this in for the 3.8.0 releases
since currently the LLVM_LINK_LLVM_DYLIB build produces broken
binaries on both trees.
         Jack

Index: cmake/modules/AddLLVM.cmake
===================================================================
--- cmake/modules/AddLLVM.cmake (revision 259475)
+++ cmake/modules/AddLLVM.cmake (working copy)
@@ -468,20 +468,23 @@
     endif()
   endif()

-  # Add the explicit dependency information for this library.
-  #
-  # It would be nice to verify that we have the dependencies for this library
-  # name, but using get_property(... SET) doesn't suffice to determine if a
-  # property has been set to an empty value.
-  get_property(lib_deps GLOBAL PROPERTY LLVMBUILD_LIB_DEPS_${name})
-
-  if (LLVM_LINK_LLVM_DYLIB AND NOT ARG_STATIC AND NOT
ARG_DISABLE_LLVM_LINK_LLVM_DYLIB)
-    set(llvm_libs LLVM)
+  if (DEFINED LLVM_LINK_COMPONENTS OR DEFINED ARG_LINK_COMPONENTS)
+    if (LLVM_LINK_LLVM_DYLIB AND NOT ARG_DISABLE_LLVM_LINK_LLVM_DYLIB)
+      set(llvm_libs LLVM)
+    else()
+      llvm_map_components_to_libnames(llvm_libs
+       ${ARG_LINK_COMPONENTS}
+       ${LLVM_LINK_COMPONENTS}
+       )
+    endif()
   else()
-    llvm_map_components_to_libnames(llvm_libs
-      ${ARG_LINK_COMPONENTS}
-      ${LLVM_LINK_COMPONENTS}
-      )
+    # Components have not been defined explicitly in CMake, so add the
+    # dependency information for this library as defined by LLVMBuild.
+    #
+    # It would be nice to verify that we have the dependencies for this library
+    # name, but using get_property(... SET) doesn't suffice to determine if a
+    # property has been set to an empty value.
+    get_property(lib_deps GLOBAL PROPERTY LLVMBUILD_LIB_DEPS_${name})
   endif()

   if(CMAKE_VERSION VERSION_LESS 2.8.12)
@@ -882,14 +885,11 @@

   set(LLVM_REQUIRES_RTTI OFF)

+  list(APPEND LLVM_LINK_COMPONENTS Support) # gtest needs it for raw_ostream
   add_llvm_executable(${test_name} IGNORE_EXTERNALIZE_DEBUGINFO ${ARGN})
   set(outdir ${CMAKE_CURRENT_BINARY_DIR}/${CMAKE_CFG_INTDIR})
   set_output_directory(${test_name} BINARY_DIR ${outdir} LIBRARY_DIR ${outdir})
-  target_link_libraries(${test_name}
-    gtest
-    gtest_main
-    LLVMSupport # gtest needs it for raw_ostream.
-    )
+  target_link_libraries(${test_name} gtest_main gtest)

   add_dependencies(${test_suite} ${test_name})
   get_target_property(test_suite_folder ${test_suite} FOLDER)
Index: cmake/modules/LLVM-Config.cmake
===================================================================
--- cmake/modules/LLVM-Config.cmake (revision 259475)
+++ cmake/modules/LLVM-Config.cmake (working copy)
@@ -40,10 +40,19 @@
     # done in case libLLVM does not contain all of the components
     # the target requires.
     #
-    # TODO strip LLVM_DYLIB_COMPONENTS out of link_components.
+    # Strip LLVM_DYLIB_COMPONENTS out of link_components.
     # To do this, we need special handling for "all", since that
     # may imply linking to libraries that are not included in
     # libLLVM.
+
+    if (DEFINED link_components AND DEFINED LLVM_DYLIB_COMPONENTS)
+      if("${LLVM_DYLIB_COMPONENTS}" STREQUAL "all")
+        set(link_components "")
+      else()
+        list(REMOVE_ITEM link_components ${LLVM_DYLIB_COMPONENTS})
+      endif()
+    endif()
+
     target_link_libraries(${executable} LLVM)
   endif()

Index: utils/unittest/CMakeLists.txt
===================================================================
--- utils/unittest/CMakeLists.txt (revision 259475)
+++ utils/unittest/CMakeLists.txt (working copy)
@@ -32,10 +32,6 @@
   add_definitions( -DGTEST_HAS_PTHREAD=0 )
 endif()

-set(LIBS
-  LLVMSupport # Depends on llvm::raw_ostream
-)
-
 find_library(PTHREAD_LIBRARY_PATH pthread)
 if (PTHREAD_LIBRARY_PATH)
   list(APPEND LIBS pthread)
@@ -46,6 +42,9 @@

   LINK_LIBS
   ${LIBS}
+
+  LINK_COMPONENTS
+  Support # Depends on llvm::raw_ostream
 )

 add_subdirectory(UnitTestMain)
Index: utils/unittest/UnitTestMain/CMakeLists.txt
===================================================================
--- utils/unittest/UnitTestMain/CMakeLists.txt (revision 259475)
+++ utils/unittest/UnitTestMain/CMakeLists.txt (working copy)
@@ -3,5 +3,7 @@

   LINK_LIBS
   gtest
-  LLVMSupport # Depends on llvm::cl
+
+  LINK_COMPONENTS
+  Support # Depends on llvm::cl
   )