[BOLT] Fix LLVM_APPEND_VC_REV support (#142410)

The CMake flag LLVM_APPEND_VC_REV can be passed when building BOLT a
BOLT to prevent including a VC Revision. This patch enables this
functionality.

Usage: `-DLLVM_APPEND_VC_REV=OFF` when running CMake.

Author: paschalis-mpeis

bolt/lib/Utils/CMakeLists.txt

@@ -6,12 +6,25 @@ set(version_inc "${CMAKE_CURRENT_BINARY_DIR}/VCSVersion.inc")
 
 set(generate_vcs_version_script "${LLVM_CMAKE_DIR}/GenerateVersionFromVCS.cmake")
 
+if(llvm_vc AND LLVM_APPEND_VC_REV)
+  set(llvm_source_dir ${LLVM_MAIN_SRC_DIR})
+endif()
+if(LLVM_VC_REPOSITORY AND LLVM_VC_REVISION)
+  set(llvm_source_dir ${LLVM_SOURCE_DIR})
+  set(llvm_vc_repository ${LLVM_VC_REPOSITORY})
+  set(llvm_vc_revision ${LLVM_VC_REVISION})
+endif()
+if(bolt_vc AND LLVM_APPEND_VC_REV)
+  set(bolt_source_dir ${BOLT_SOURCE_DIR})
+endif()
+
 # Create custom target to generate the VC revision include.
 add_custom_command(OUTPUT "${version_inc}"
   DEPENDS "${llvm_vc}" "${bolt_vc}" "${generate_vcs_version_script}"
   COMMAND ${CMAKE_COMMAND} "-DNAMES=BOLT"
+                           "-DLLVM_SOURCE_DIR=${llvm_source_dir}"
+                           "-DBOLT_SOURCE_DIR=${bolt_source_dir}"
                            "-DHEADER_FILE=${version_inc}"
-                           "-DBOLT_SOURCE_DIR=${BOLT_SOURCE_DIR}"
                            "-DLLVM_VC_REPOSITORY=${llvm_vc_repository}"
                            "-DLLVM_VC_REVISION=${llvm_vc_revision}"
                            "-DLLVM_FORCE_VC_REVISION=${LLVM_FORCE_VC_REVISION}"