[cmake] rework LLVM_LINK_LLVM_DYLIB option handling

Summary:
This diff attempts to address the concerns raised in
http://reviews.llvm.org/D12488.

We introduce a new USE_SHARED option to llvm_config,
which, if set, causes the target to be linked against
libLLVM.

add_llvm_utility now uniformly disables linking against
libLLVM. These utilities are not intended for distribution,
and this keeps the option handling more centralised.

llvm-shlib is now processes before any other "tools"
subdirectories, ensuring the libLLVM target is defined
before its dependents.

One main difference from what was requested: llvm_config
does not prune LLVM_DYLIB_COMPONENTS from the components
passed into explicit_llvm_config. This is because the "all"
component does something special, adding additional
libraries (namely libLTO). Adding the component libraries
after libLLVM should not be a problem, as symbols will be
resolved in libLLVM first.

Finally, I'm not really happy with the
DISABLE_LLVM_LINK_LLVM option, but I'm not sure of a
better way to get the following:
 - link all tools and shared libraries to libLLVM if
   LLVM_LINK_LLVM_DYLIB is set
 - some way of explicitly *not* doing so for utilities
   and libLLVM itself
Suggestions for improvement here are particularly welcome.

Reviewers: beanz

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D12590

llvm-svn: 246918

1 files changed, 6 insertions, 6 deletions

diff --git a/llvm/cmake/modules/AddLLVM.cmake b/llvm/cmake/modules/AddLLVM.cmake
index f53b89d32ab..0f3b660b95f 100644
--- a/llvm/cmake/modules/AddLLVM.cmake
+++ b/llvm/cmake/modules/AddLLVM.cmake
@@ -610,13 +610,13 @@ macro(add_llvm_executable name)
     add_llvm_symbol_exports( ${name} ${LLVM_EXPORTED_SYMBOL_FILE} )
   endif(LLVM_EXPORTED_SYMBOL_FILE)
 
-  set(EXCLUDE_FROM_ALL OFF)
-  set_output_directory(${name} ${LLVM_RUNTIME_OUTPUT_INTDIR} ${LLVM_LIBRARY_OUTPUT_INTDIR})
   if (LLVM_LINK_LLVM_DYLIB AND NOT ARG_DISABLE_LLVM_LINK_LLVM_DYLIB)
-    target_link_libraries(${name} LLVM)
-  else()
-    llvm_config( ${name} ${LLVM_LINK_COMPONENTS} )
+    set(USE_SHARED USE_SHARED)
   endif()
+
+  set(EXCLUDE_FROM_ALL OFF)
+  set_output_directory(${name} ${LLVM_RUNTIME_OUTPUT_INTDIR} ${LLVM_LIBRARY_OUTPUT_INTDIR})
+  llvm_config( ${name} ${USE_SHARED} ${LLVM_LINK_COMPONENTS} )
   if( LLVM_COMMON_DEPENDS )
     add_dependencies( ${name} ${LLVM_COMMON_DEPENDS} )
   endif( LLVM_COMMON_DEPENDS )
@@ -677,7 +677,7 @@ endmacro(add_llvm_example name)
 
 
 macro(add_llvm_utility name)
-  add_llvm_executable(${name} ${ARGN})
+  add_llvm_executable(${name} DISABLE_LLVM_LINK_LLVM_DYLIB ${ARGN})
   set_target_properties(${name} PROPERTIES FOLDER "Utils")
   if( LLVM_INSTALL_UTILS )
     install (TARGETS ${name}