Index: clang/lib/Basic/SourceManager.cpp
===================================================================
--- clang/lib/Basic/SourceManager.cpp
+++ clang/lib/Basic/SourceManager.cpp
@@ -1791,7 +1791,12 @@
     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
Index: clang/unittests/Basic/SourceManagerTest.cpp
===================================================================
--- clang/unittests/Basic/SourceManagerTest.cpp
+++ clang/unittests/Basic/SourceManagerTest.cpp
@@ -343,6 +343,83 @@
   EXPECT_TRUE(defLoc2.isFileID());
 }
 
+TEST_F(SourceManagerTest, getMacroArgExpandedLocationRegression) {
+  const char *main_c_content =
+    "#include \"/modulefoo/foo.h\"\n"
+    "#define FOO234878786(a) (a + a)\n"
+    "const int a = 1;\n"
+    "const int b = FOO234878786(a);\n";
+  std::unique_ptr<llvm::MemoryBuffer> main_c_buffer =
+      llvm::MemoryBuffer::getMemBuffer(main_c_content);
+  const FileEntry *main_c_file = FileMgr.getVirtualFile("/main.c", main_c_buffer->getBufferSize(), 0);
+  SourceMgr.overrideFileContents(main_c_file, std::move(main_c_buffer));
+  FileID main_c_ID = SourceMgr.getOrCreateFileID(main_c_file, clang::SrcMgr::C_User);
+  SourceMgr.setMainFileID(main_c_ID);
+
+  const char *module_map_content =
+    "module foo [system] [extern_c] {\n"
+    "  extern module submodule \"submodule.modulemap\"\n"
+    "  module foo {\n"
+    "    header \"foo.h\"\n"
+    "    export *\n"
+    "  }\n"
+    "}\n";
+  std::unique_ptr<llvm::MemoryBuffer> module_map_buffer = llvm::MemoryBuffer::getMemBuffer(module_map_content);
+  const FileEntry *module_map_file = FileMgr.getVirtualFile("/modulefoo/module.map", module_map_buffer->getBufferSize(), 0);
+  SourceMgr.overrideFileContents(module_map_file, std::move(module_map_buffer));
+
+  const char *foo_h_content = "\n";
+  std::unique_ptr<llvm::MemoryBuffer> foo_h_buffer = llvm::MemoryBuffer::getMemBuffer(foo_h_content);
+  const FileEntry *foo_h_file = FileMgr.getVirtualFile("/modulefoo/foo.h", foo_h_buffer->getBufferSize(), 0);
+  SourceMgr.overrideFileContents(foo_h_file, std::move(foo_h_buffer));
+
+  const char *submodule_h_content = "\n";
+  std::unique_ptr<llvm::MemoryBuffer> submodule_h_buffer = llvm::MemoryBuffer::getMemBuffer(submodule_h_content);
+  const FileEntry *submodule_h_file = FileMgr.getVirtualFile("/modulefoo/submodule.h", submodule_h_buffer->getBufferSize(), 0);
+  SourceMgr.overrideFileContents(submodule_h_file, std::move(submodule_h_buffer));
+
+  const char *submodule_map_content =
+    "module foo.submodule [system] [extern_c] {\n"
+    "  header \"submodule.h\"\n"
+    "  export *\n"
+    "}\n";
+  std::unique_ptr<llvm::MemoryBuffer> submodule_map_buffer = llvm::MemoryBuffer::getMemBuffer(submodule_map_content);
+  const FileEntry *submodule_map_file = FileMgr.getVirtualFile("/modulefoo/submodule.modulemap", submodule_map_buffer->getBufferSize(), 0);
+  SourceMgr.overrideFileContents(submodule_map_file, std::move(submodule_map_buffer));
+
+  TrivialModuleLoader ModLoader;
+  HeaderSearch HeaderInfo(std::make_shared<HeaderSearchOptions>(), SourceMgr,
+                          Diags, LangOpts, &*Target);
+
+  Preprocessor PP(std::make_shared<PreprocessorOptions>(), Diags, LangOpts,
+                  SourceMgr, HeaderInfo, ModLoader,
+                  /*IILookup =*/nullptr,
+                  /*OwnsHeaderSearch =*/false);
+
+  // Ensure we can get expanded locations in presence of implicit includes.
+  // These are different than normal includes since predefines buffer doesn't
+  // have a valid insertion location.
+  PP.setPredefines("#include \"/implicit-header.h\"");
+  FileMgr.getVirtualFile("/implicit-header.h", 0, 0);
+  PP.Initialize(*Target);
+  PP.EnterMainSourceFile();
+
+
+  std::vector<Token> toks;
+  while (1) {
+    Token tok;
+    PP.Lex(tok);
+    if (tok.is(tok::eof))
+      break;
+    toks.push_back(tok);
+  }
+ 
+  SourceLocation macroArgLoc = SourceMgr.translateLineCol(main_c_ID, 4, 28);
+  SourceLocation macroArgExpandedLoc = SourceMgr.getMacroArgExpandedLocation(macroArgLoc);
+  
+  EXPECT_EQ(macroArgExpandedLoc, toks[13].getLocation());
+}
+
 namespace {
 
 struct MacroAction {