[llvm-diff] Create libLLVMDiff library

Some tools may want to use the LLVM "diff" code. Move the code into a
library for easy use.

No functionality change intende.

Differential Revision: https://reviews.llvm.org/D107392

llvm/tools/llvm-diff/CMakeLists.txt

@@ -6,10 +6,10 @@ set(LLVM_LINK_COMPONENTS
 
 add_llvm_tool(llvm-diff
   llvm-diff.cpp
-  DiffConsumer.cpp
-  DiffLog.cpp
-  DifferenceEngine.cpp
 
   DEPENDS
   intrinsics_gen
   )
+
+add_subdirectory(lib)
+target_link_libraries(llvm-diff PRIVATE LLVMDiff)

llvm/tools/llvm-diff/lib/CMakeLists.txt

@@ -0,0 +1,14 @@
+set(LLVM_LINK_COMPONENTS
+    Core
+    Support
+    )
+
+add_llvm_library(LLVMDiff
+  STATIC
+  DiffConsumer.cpp
+  DiffConsumer.h
+  DifferenceEngine.cpp
+  DifferenceEngine.h
+  DiffLog.cpp
+  DiffLog.h
+  )

llvm/tools/llvm-diff/llvm-diff.cpp

@@ -10,8 +10,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "DiffLog.h"
+#include "lib/DiffLog.h"
-#include "DifferenceEngine.h"
+#include "lib/DifferenceEngine.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/IR/LLVMContext.h"
 #include "llvm/IR/Module.h"

llvm/tools/llvm-livepatch/CMakeLists.txt

@@ -0,0 +1,12 @@
+set(LLVM_LINK_COMPONENTS
+  Core
+  IRReader
+  Support
+  )
+
+add_llvm_tool(llvm-livepatch
+  llvm-livepatch.cpp
+
+  DEPENDS
+  intrinsics_gen
+  )