gn build: Add check-builtins target.

Tested on aarch64 Linux and x86_64 Linux.

Reviewers: aeubanks, nico

Reviewed By: aeubanks

Pull Request: llvm#134482

Author: pcc

llvm/utils/gn/build/sync_source_lists_from_cmake.py

@@ -108,6 +108,12 @@ def get_sources(source_re, text):
 
         gn_cpp = get_sources(gn_cpp_re, open(gn_file).read())
         gn_cpp |= get_sources(gn_cpp_re2, open(gn_file).read())
+
+        sources_file = os.path.join(os.path.dirname(gn_file), "sources.gni")
+        if os.path.exists(sources_file):
+            gn_cpp |= get_sources(gn_cpp_re, open(sources_file).read())
+            gn_cpp |= get_sources(gn_cpp_re2, open(sources_file).read())
+
         cmake_cpp = get_sources(cmake_cpp_re, open(cmake_file).read())
 
         if gn_cpp == cmake_cpp:

llvm/utils/gn/secondary/BUILD.gn

@@ -10,6 +10,7 @@ group("default") {
     "//compiler-rt",
     "//compiler-rt/include",
     "//compiler-rt/lib/scudo",
+    "//compiler-rt/test/builtins",
     "//lld/test",
     "//lldb/test",
     "//llvm/test",