[SourceManager] Skip module maps when searching files for macro arguments

Differential Revision: https://reviews.llvm.org/D86230

Author: jkorous-apple

clang/lib/Basic/SourceManager.cpp

@@ -1761,7 +1761,12 @@ void SourceManager::computeMacroArgsCache(MacroArgsMap &MacroArgsCache,
     if (Invalid)
       return;
     if (Entry.isFile()) {
-      SourceLocation IncludeLoc = Entry.getFile().getIncludeLoc();
+      auto File = Entry.getFile();
+      if (File.getFileCharacteristic() == C_User_ModuleMap ||
+          File.getFileCharacteristic() == C_System_ModuleMap)
+        continue;
+
+      SourceLocation IncludeLoc = File.getIncludeLoc();
       bool IncludedInFID =
           (IncludeLoc.isValid() && isInFileID(IncludeLoc, FID)) ||
           // Predefined header doesn't have a valid include location in main