Make LLVM_APPEND_VC_REV=OFF affect clang, lld, and lldb as well.

[thakis]

Summary

When LLVM_APPEND_VC_REV=OFF is set, the current git hash is no
longer embedded into binaries (mostly for --version output).
Without it, most binaries need to relink after every single
commit, even if they didn't change otherwise (due to, say,
a documentation-only commit).

LLVM_APPEND_VC_REV is ON by default, so this doesn't change the
default behavior of anything.

With this, all clients of GenerateVersionFromVCS.cmake honor
LLVM_APPEND_VC_REV.

[thakis]

A very late follow-up to my question in D37272 :)

[rnk]

lgtm

llvm/cmake/modules/LLVMConfig.cmake.in

81

This here should make the standalone build configs work, I think.

clang/lib/Basic/CMakeLists.txt

 set(LLVM_LINK_COMPONENTS
   Core
   MC
   Support
   )
 
 find_first_existing_vc_file("${LLVM_MAIN_SRC_DIR}" llvm_vc)
 find_first_existing_vc_file("${CLANG_SOURCE_DIR}" clang_vc)
 
 # The VC revision include that we want to generate.
 set(version_inc "${CMAKE_CURRENT_BINARY_DIR}/VCSVersion.inc")
 
 set(generate_vcs_version_script "${LLVM_CMAKE_PATH}/GenerateVersionFromVCS.cmake")
 
-if(llvm_vc)
+if(llvm_vc AND LLVM_APPEND_VC_REV)
   set(llvm_source_dir ${LLVM_MAIN_SRC_DIR})
 endif()
-if(clang_vc)
+if(clang_vc AND LLVM_APPEND_VC_REV)
   set(clang_source_dir ${CLANG_SOURCE_DIR})
 endif()
 
 # Create custom target to generate the VC revision include.
 add_custom_command(OUTPUT "${version_inc}"
   DEPENDS "${llvm_vc}" "${clang_vc}" "${generate_vcs_version_script}"
   COMMAND ${CMAKE_COMMAND} "-DNAMES=\"LLVM;CLANG\""
                            "-DLLVM_SOURCE_DIR=${llvm_source_dir}"

lld/Common/CMakeLists.txt

 if(NOT LLD_BUILT_STANDALONE)
   set(tablegen_deps intrinsics_gen)
 endif()
 
 find_first_existing_vc_file("${LLVM_MAIN_SRC_DIR}" llvm_vc)
 find_first_existing_vc_file("${LLD_SOURCE_DIR}" lld_vc)
 
 set(version_inc "${CMAKE_CURRENT_BINARY_DIR}/VCSVersion.inc")
 set(generate_vcs_version_script "${LLVM_CMAKE_PATH}/GenerateVersionFromVCS.cmake")
 
-if(lld_vc)
+if(lld_vc AND LLVM_APPEND_VC_REV)
   set(lld_source_dir ${LLD_SOURCE_DIR})
 endif()
 
 add_custom_command(OUTPUT "${version_inc}"
   DEPENDS "${lld_vc}" "${generate_vcs_version_script}"
   COMMAND ${CMAKE_COMMAND} "-DNAMES=LLD"
-  "-DLLD_SOURCE_DIR=${LLD_SOURCE_DIR}"
+  "-DLLD_SOURCE_DIR=${lld_source_dir}"
   "-DHEADER_FILE=${version_inc}"
   -P "${generate_vcs_version_script}")
 
 # Mark the generated header as being generated.
 set_source_files_properties("${version_inc}"
   PROPERTIES GENERATED TRUE
   HEADER_FILE_ONLY TRUE)
 

lldb/source/CMakeLists.txt

if(EXISTS "${file}")
     set(lldb_vc "${file}")
     break()
   endif()
 endforeach()
 
 set(version_inc "${CMAKE_CURRENT_BINARY_DIR}/VCSVersion.inc")
 set(generate_vcs_version_script "${LLVM_CMAKE_PATH}/GenerateVersionFromVCS.cmake")
 
-if(lldb_vc)
+if(lldb_vc AND LLVM_APPEND_VC_REV)
   set(lldb_source_dir ${LLDB_SOURCE_DIR})
 endif()
 
 add_custom_command(OUTPUT "${version_inc}"
   DEPENDS "${lldb_vc}" "${generate_vcs_version_script}"
   COMMAND ${CMAKE_COMMAND} "-DNAMES=LLDB"
-                           "-DLLDB_SOURCE_DIR=${LLDB_SOURCE_DIR}"
+                           "-DLLDB_SOURCE_DIR=${lldb_source_dir}"
                            "-DHEADER_FILE=${version_inc}"
                            -P "${generate_vcs_version_script}")
 
 # Mark the generated header as being generated.
 set_source_files_properties("${version_inc}"
   PROPERTIES GENERATED TRUE
              HEADER_FILE_ONLY TRUE)
 

llvm/cmake/modules/LLVMConfig.cmake.in

 
 set(LLVM_ON_UNIX @LLVM_ON_UNIX@)
 
 set(LLVM_LIBDIR_SUFFIX @LLVM_LIBDIR_SUFFIX@)
 
 set(LLVM_INCLUDE_DIRS "@LLVM_CONFIG_INCLUDE_DIRS@")
 set(LLVM_LIBRARY_DIRS "@LLVM_CONFIG_LIBRARY_DIRS@")
 
+set(LLVM_APPEND_VC_REV "@LLVM_APPEND_VC_REV@")
+
 # These variables are duplicated for install tree but they have different
 # values for build tree.  LLVM_INCLUDE_DIRS contains both source
 # and generated include directories while the following variables have
 # them split.
 set(LLVM_INCLUDE_DIR "@LLVM_CONFIG_INCLUDE_DIR@")
 set(LLVM_MAIN_INCLUDE_DIR "@LLVM_CONFIG_MAIN_INCLUDE_DIR@")
 set(LLVM_LIBRARY_DIR "@LLVM_CONFIG_LIBRARY_DIRS@")
 

llvm/docs/CMake.rst

 
 **LLVM_BUILD_BENCHMARKS**:BOOL
   Adds benchmarks to the list of default targets. Defaults to OFF.
 
 **LLVM_INCLUDE_BENCHMARKS**:BOOL
   Generate build targets for the LLVM benchmarks. Defaults to ON.
 
 **LLVM_APPEND_VC_REV**:BOOL
-  Embed version control revision info (svn revision number or Git revision id).
+  Embed version control revision info (Git revision id).
   The version info is provided by the ``LLVM_REVISION`` macro in
   ``llvm/include/llvm/Support/VCSRevision.h``. Developers using git who don't
   need revision info can disable this option to avoid re-linking most binaries
   after a branch switch. Defaults to ON.
 
 **LLVM_ENABLE_THREADS**:BOOL
   Build with threads support, if available. Defaults to ON.