From 110ec72cff8a19c7125e6a69c691f1f67f755982 Mon Sep 17 00:00:00 2001
From: comex <comexk@gmail.com>
Date: Sun, 9 Aug 2015 02:55:36 -0400
Subject: [PATCH] Merge pull request #2816 from comex/huh-where-did-this-go

Make the LLVM detect script verify that the dynamic library actually exists.
---
 CMakeTests/FindLLVM.cmake | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/CMakeTests/FindLLVM.cmake b/CMakeTests/FindLLVM.cmake
index 7fe664f6ef..cfcfaedb92 100644
--- a/CMakeTests/FindLLVM.cmake
+++ b/CMakeTests/FindLLVM.cmake
@@ -1,6 +1,9 @@
 # This file only exists because LLVM's cmake files are broken.
 # This affects both LLVM 3.4 and 3.5.
 # Hopefully when they fix their cmake system we don't need this garbage.
+
+include(CheckLibraryExists)
+
 list(APPEND LLVM_CONFIG_EXECUTABLES "llvm-config")
 list(APPEND LLVM_CONFIG_EXECUTABLES "llvm-config-3.5")
 list(APPEND LLVM_CONFIG_EXECUTABLES "llvm-config-3.4")
@@ -11,13 +14,16 @@ foreach(LLVM_CONFIG_NAME ${LLVM_CONFIG_EXECUTABLES})
 		execute_process(COMMAND ${LLVM_CONFIG_EXE} --version OUTPUT_VARIABLE LLVM_PACKAGE_VERSION
 			OUTPUT_STRIP_TRAILING_WHITESPACE )
 		if (${LLVM_PACKAGE_VERSION} VERSION_GREATER "3.3")
-			set(LLVM_FOUND 1)
 			execute_process(COMMAND ${LLVM_CONFIG_EXE} --includedir OUTPUT_VARIABLE LLVM_INCLUDE_DIRS
 				OUTPUT_STRIP_TRAILING_WHITESPACE )
 			execute_process(COMMAND ${LLVM_CONFIG_EXE} --ldflags OUTPUT_VARIABLE LLVM_LDFLAGS
 				OUTPUT_STRIP_TRAILING_WHITESPACE )
-			set(LLVM_LIBRARIES "${LLVM_LDFLAGS} -lLLVM-${LLVM_PACKAGE_VERSION}")
-			break()
+			check_library_exists(LLVM-${LLVM_PACKAGE_VERSION} LLVMVerifyFunction "${LLVM_LDFLAGS}" HAVE_DYNAMIC_LLVM_${LLVM_PACKAGE_VERSION})
+			if (HAVE_DYNAMIC_LLVM_${LLVM_PACKAGE_VERSION})
+				set(LLVM_LIBRARIES "${LLVM_LDFLAGS} -lLLVM-${LLVM_PACKAGE_VERSION}")
+				set(LLVM_FOUND 1)
+				break()
+			endif()
 		endif()
 	endif()
 endforeach()