[CMAKE] Move version control macros to AddLLVM.cmake so they can be reused by clang, etc.

[hintonda]

Summary

Move version control macros, find_first_existing_file and
find_first_existing_vc_file to AddLLVM.cmake so they can be reused by sub projects
like clang.

Please see D35533 for an example of where this would be useful.

[minseong.kim]

LGTM

I just checked that this patch is working correctly from clang. I am just wondering if there is a possibility of using clang only without llvm. If this is the case, clang might need its own version control macros ? Or no such case.

[hintonda]

I just checked that this patch is working correctly from clang. I am just wondering if there is a possibility of using clang only without llvm. If this is the case, clang might need its own version control macros ? Or no such case.

LLVM is required to build clang, either in-tree or found via llvm-config for out-of-tree builds.

For in-tree builds, AddLLVM.cmake gets included by llvm/CMakeLists.txt, whereas it will be included by clang/CMakeLists.txt for out of tree builds.

[minseong.kim]

I have tested this patch with git, git-svn, svn and repo. It is working as expected with clang's lib/Basic/CMakeLists.txt.
LGTM.

cmake/modules/AddLLVM.cmake

function(setup_dependency_debugging name)
   endif()
 
   set(deny_attributes_gen "(deny file* (literal \"${LLVM_BINARY_DIR}/include/llvm/IR/Attributes.gen\"))")
   set(deny_intrinsics_gen "(deny file* (literal \"${LLVM_BINARY_DIR}/include/llvm/IR/Intrinsics.gen\"))")
 
   set(sandbox_command "sandbox-exec -p '(version 1) (allow default) ${deny_attributes_gen} ${deny_intrinsics_gen}'")
   set_target_properties(${name} PROPERTIES RULE_LAUNCH_COMPILE ${sandbox_command})
 endfunction()
+
+# Figure out if we can track VC revisions.
+function(find_first_existing_file out_var)
+  foreach(file ${ARGN})
+    if(EXISTS "${file}")
+      set(${out_var} "${file}" PARENT_SCOPE)
+      return()
+    endif()
+  endforeach()
+endfunction()
+
+macro(find_first_existing_vc_file out_var path)
+    find_program(git_executable NAMES git git.exe git.cmd)
+    # Run from a subdirectory to force git to print an absolute path.
+    execute_process(COMMAND ${git_executable} rev-parse --git-dir
+      WORKING_DIRECTORY ${path}/cmake
+      RESULT_VARIABLE git_result
+      OUTPUT_VARIABLE git_dir
+      ERROR_QUIET)
+    if(git_result EQUAL 0)
+      string(STRIP "${git_dir}" git_dir)
+      set(${out_var} "${git_dir}/logs/HEAD")
+      # some branchless cases (e.g. 'repo') may not yet have .git/logs/HEAD
+      if (NOT EXISTS "${git_dir}/logs/HEAD")
+        file(WRITE "${git_dir}/logs/HEAD" "")
+      endif()
+    else()
+      find_first_existing_file(${out_var}
+        "${path}/.svn/wc.db"   # SVN 1.7
+        "${path}/.svn/entries" # SVN 1.6
+      )
+    endif()
+endmacro()

include/llvm/Support/CMakeLists.txt

-# Figure out if we can track VC revisions.
-function(find_first_existing_file out_var)
-  foreach(file ${ARGN})
-    if(EXISTS "${file}")
-      set(${out_var} "${file}" PARENT_SCOPE)
-      return()
-    endif()
-  endforeach()
-endfunction()
-
-macro(find_first_existing_vc_file out_var path)
-    find_program(git_executable NAMES git git.exe git.cmd)
-    # Run from a subdirectory to force git to print an absolute path.
-    execute_process(COMMAND ${git_executable} rev-parse --git-dir
-      WORKING_DIRECTORY ${path}/cmake
-      RESULT_VARIABLE git_result
-      OUTPUT_VARIABLE git_dir
-      ERROR_QUIET)
-    if(git_result EQUAL 0)
-      string(STRIP "${git_dir}" git_dir)
-      set(${out_var} "${git_dir}/logs/HEAD")
-      # some branchless cases (e.g. 'repo') may not yet have .git/logs/HEAD
-      if (NOT EXISTS "${git_dir}/logs/HEAD")
-        file(WRITE "${git_dir}/logs/HEAD" "")
-      endif()
-    else()
-      find_first_existing_file(${out_var}
-        "${path}/.svn/wc.db"   # SVN 1.7
-        "${path}/.svn/entries" # SVN 1.6
-      )
-    endif()
-endmacro()
-
 find_first_existing_vc_file(llvm_vc "${LLVM_MAIN_SRC_DIR}")
 
 # The VC revision include that we want to generate.
 set(version_inc "${CMAKE_CURRENT_BINARY_DIR}/VCSRevision.h")
 
 set(get_svn_script "${LLVM_CMAKE_PATH}/GenerateVersionFromCVS.cmake")
 
 file(WRITE "${version_inc}.empty" "")