[clang] [clang-format][NFC] Don't always rebuild clang-format-check-format (PR #203828)

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llvmorg-github-actions[bot] wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang-format

Author: owenca (owenca)

<details>
<summary>Changes</summary>

Instead, checking the format of clan-format source only if the built clang-format binary or one of the source files is newer.

---
Full diff: https://github.com/llvm/llvm-project/pull/203828.diff


1 Files Affected:

- (modified) clang/lib/Format/CMakeLists.txt (+4-1) 


``````````diff
diff --git a/clang/lib/Format/CMakeLists.txt b/clang/lib/Format/CMakeLists.txt
index 50c0683dc9b7f..3e19151790440 100644
--- a/clang/lib/Format/CMakeLists.txt
+++ b/clang/lib/Format/CMakeLists.txt
@@ -45,9 +45,12 @@ set(check_format_depends)
 set(i 0)
 foreach(file IN LISTS files)
   add_custom_command(OUTPUT check_format_depend_${i}
-    COMMAND clang-format ${file} | diff -u ${file} -
+    COMMAND clang-format ${file} | diff -u ${file} - &&
+            touch check_format_depend_${i}
     VERBATIM
     COMMENT "Checking format of ${file}"
+    DEPENDS clang-format
+            ${file}
     )
   list(APPEND check_format_depends check_format_depend_${i})
   math(EXPR i ${i}+1)

``````````

</details>


https://github.com/llvm/llvm-project/pull/203828