Index: clang/lib/Tooling/Tooling.cpp
===================================================================
--- clang/lib/Tooling/Tooling.cpp
+++ clang/lib/Tooling/Tooling.cpp
@@ -435,13 +435,22 @@
 static void injectResourceDir(CommandLineArguments &Args, const char *Argv0,
                               void *MainAddr) {
   // Allow users to override the resource dir.
-  for (StringRef Arg : Args)
+  // Don't search/inject past "--", as the subsequent arguments are only file
+  // names.
+  auto FlagsEnd = Args.end();
+  for (auto B = Args.begin(), I = B, E = Args.end(); I != E; ++I) {
+    StringRef Arg = *I;
+    if (Arg == "--") {
+      FlagsEnd = I;
+      break;
+    }
     if (Arg.startswith("-resource-dir"))
       return;
+  }
 
   // If there's no override in place add our resource dir.
-  Args.push_back("-resource-dir=" +
-                 CompilerInvocation::GetResourcesPath(Argv0, MainAddr));
+  Args.insert(FlagsEnd, "-resource-dir=" + CompilerInvocation::GetResourcesPath(
+                                               Argv0, MainAddr));
 }
 
 int ClangTool::run(ToolAction *Action) {
Index: clang/test/ClangScanDeps/Inputs/regular_cdb.json
===================================================================
--- clang/test/ClangScanDeps/Inputs/regular_cdb.json
+++ clang/test/ClangScanDeps/Inputs/regular_cdb.json
@@ -11,7 +11,7 @@
 },
 {
   "directory": "DIR",
-  "command": "clang -E DIR/regular_cdb_input.cpp -IInputs -o adena.o",
+  "command": "clang -E -IInputs -o adena.o -- DIR/regular_cdb_input.cpp",
   "file": "DIR/regular_cdb_input.cpp"
 }
 ]
Index: clang/tools/clang-scan-deps/ClangScanDeps.cpp
===================================================================
--- clang/tools/clang-scan-deps/ClangScanDeps.cpp
+++ clang/tools/clang-scan-deps/ClangScanDeps.cpp
@@ -421,14 +421,18 @@
         bool HasMQ = false;
         bool HasMD = false;
         bool HasResourceDir = false;
+        auto FlagsEnd = llvm::find(Args, "--");
+
         // We need to find the last -o value.
-        if (!Args.empty()) {
-          std::size_t Idx = Args.size() - 1;
-          for (auto It = Args.rbegin(); It != Args.rend(); ++It) {
-            StringRef Arg = Args[Idx];
+        if (FlagsEnd != Args.begin()) {
+          // Reverse scan, starting at the end or at the element before "--".
+          for (auto RB = llvm::make_reverse_iterator(FlagsEnd), RI = RB,
+                    RE = Args.rend();
+               RI != RE; ++RI) {
+            StringRef Arg = *RI;
             if (LastO.empty()) {
-              if (Arg == "-o" && It != Args.rbegin())
-                LastO = Args[Idx + 1];
+              if (Arg == "-o" && RI != RB)
+                LastO = RI[-1]; // Next argument (reverse iterator)
               else if (Arg.startswith("-o"))
                 LastO = Arg.drop_front(2).str();
             }
@@ -440,12 +444,11 @@
               HasMD = true;
             if (Arg == "-resource-dir")
               HasResourceDir = true;
-            --Idx;
           }
         }
         // If there's no -MT/-MQ Driver would add -MT with the value of the last
         // -o option.
-        tooling::CommandLineArguments AdjustedArgs = Args;
+        tooling::CommandLineArguments AdjustedArgs(Args.begin(), FlagsEnd);
         AdjustedArgs.push_back("-o");
         AdjustedArgs.push_back("/dev/null");
         if (!HasMT && !HasMQ) {
@@ -475,6 +478,7 @@
             AdjustedArgs.push_back(std::string(ResourceDir));
           }
         }
+        AdjustedArgs.insert(AdjustedArgs.end(), FlagsEnd, Args.end());
         return AdjustedArgs;
       });
   AdjustingCompilations->appendArgumentsAdjuster(