Have llvm-c-test only use libLLVM if libLLVM has all the right components.

[beanz]

Summary

We should only have llvm-c-test use libLLVM if the library is built with the default set of components or if LLVM_DYLIB_COMPONENTS includes all the LLVM_LINK_COMPONENTS required for llvm-c-test. Making libLLVM always used causes build failures if libLLVM doesn't include all

[ributzka]

LGTM

llvm/trunk/tools/llvm-c-test/CMakeLists.txt

 set(LLVM_LINK_COMPONENTS
   ${LLVM_TARGETS_TO_BUILD}
   BitReader
   Core
   MCDisassembler
   Object
   Target
   )
 
-if(TARGET LLVM)
+# We should only have llvm-c-test use libLLVM if libLLVM is built with the
+# default list of components. Using libLLVM with custom components can result in
+# build failures.
+
+set (USE_LLVM_DYLIB FALSE)
+
+if (TARGET LLVM)
+  set (USE_LLVM_DYLIB TRUE)
+  if (DEFINED LLVM_DYLIB_COMPONENTS)
+    foreach(c in ${LLVM_LINK_COMPONENTS})
+      list(FIND LLVM_DYLIB_COMPONENTS ${c} C_IDX)
+      if (C_IDX EQUAL -1)
+        set(USE_LLVM_DYLIB FALSE)
+        break()
+      endif()
+    endforeach()
+  endif()
+endif()
+
+if(USE_LLVM_DYLIB)
   set(LLVM_LINK_COMPONENTS)
 endif()
 
 if (LLVM_COMPILER_IS_GCC_COMPATIBLE)
   set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -std=gnu99 -Wstrict-prototypes")
 endif ()
 
 add_llvm_tool(llvm-c-test
   calc.c
   disassemble.c
   helpers.c
   include-all.c
   main.c
   module.c
   object.c
   targets.c
   )
 
-# Use libLLVM.so if it is available.
-if(TARGET LLVM)
+if(USE_LLVM_DYLIB)
   target_link_libraries(llvm-c-test LLVM)
 endif()