diff --git a/clang/include/clang/Tooling/Tooling.h b/clang/include/clang/Tooling/Tooling.h
--- a/clang/include/clang/Tooling/Tooling.h
+++ b/clang/include/clang/Tooling/Tooling.h
@@ -508,7 +508,7 @@
 
 /// Creates a \c CompilerInvocation.
 CompilerInvocation *newInvocation(DiagnosticsEngine *Diagnostics,
-                                  const llvm::opt::ArgStringList &CC1Args,
+                                  ArrayRef<const char *> CC1Args,
                                   const char *const BinaryName);
 
 } // namespace tooling
diff --git a/clang/lib/Tooling/Tooling.cpp b/clang/lib/Tooling/Tooling.cpp
--- a/clang/lib/Tooling/Tooling.cpp
+++ b/clang/lib/Tooling/Tooling.cpp
@@ -161,7 +161,7 @@
 
 /// Returns a clang build invocation initialized from the CC1 flags.
 CompilerInvocation *newInvocation(DiagnosticsEngine *Diagnostics,
-                                  const llvm::opt::ArgStringList &CC1Args,
+                                  ArrayRef<const char *> CC1Args,
                                   const char *const BinaryName) {
   assert(!CC1Args.empty() && "Must at least contain the program name!");
   CompilerInvocation *Invocation = new CompilerInvocation;
@@ -339,7 +339,7 @@
 }
 
 bool ToolInvocation::run() {
-  std::vector<const char*> Argv;
+  llvm::opt::ArgStringList Argv;
   for (const std::string &Str : CommandLine)
     Argv.push_back(Str.c_str());
   const char *const BinaryName = Argv[0];
@@ -362,6 +362,17 @@
   SourceManager SrcMgr(*Diagnostics, *Files);
   Diagnostics->setSourceManager(&SrcMgr);
 
+  // We already have a cc1, just create an invocation.
+  if (CommandLine.size() >= 2 && CommandLine[1] == "-cc1") {
+    ArrayRef<const char *> CC1Args = makeArrayRef(Argv).drop_front();
+    std::unique_ptr<CompilerInvocation> Invocation(
+        newInvocation(&*Diagnostics, CC1Args, BinaryName));
+    if (Diagnostics->hasErrorOccurred())
+      return false;
+    return Action->runInvocation(std::move(Invocation), Files,
+                                 std::move(PCHContainerOps), DiagConsumer);
+  }
+
   const std::unique_ptr<driver::Driver> Driver(
       newDriver(&*Diagnostics, BinaryName, &Files->getVirtualFileSystem()));
   // The "input file not found" diagnostics from the driver are useful.
diff --git a/clang/unittests/Tooling/ToolingTest.cpp b/clang/unittests/Tooling/ToolingTest.cpp
--- a/clang/unittests/Tooling/ToolingTest.cpp
+++ b/clang/unittests/Tooling/ToolingTest.cpp
@@ -326,6 +326,46 @@
   EXPECT_TRUE(Consumer.SawSourceManager);
 }
 
+TEST(ToolInvocation, CC1Args) {
+  llvm::IntrusiveRefCntPtr<llvm::vfs::OverlayFileSystem> OverlayFileSystem(
+      new llvm::vfs::OverlayFileSystem(llvm::vfs::getRealFileSystem()));
+  llvm::IntrusiveRefCntPtr<llvm::vfs::InMemoryFileSystem> InMemoryFileSystem(
+      new llvm::vfs::InMemoryFileSystem);
+  OverlayFileSystem->pushOverlay(InMemoryFileSystem);
+  llvm::IntrusiveRefCntPtr<FileManager> Files(
+      new FileManager(FileSystemOptions(), OverlayFileSystem));
+  std::vector<std::string> Args;
+  Args.push_back("tool-executable");
+  Args.push_back("-cc1");
+  Args.push_back("-fsyntax-only");
+  Args.push_back("test.cpp");
+  clang::tooling::ToolInvocation Invocation(
+      Args, std::make_unique<SyntaxOnlyAction>(), Files.get());
+  InMemoryFileSystem->addFile(
+      "test.cpp", 0, llvm::MemoryBuffer::getMemBuffer("void foo(void);\n"));
+  EXPECT_TRUE(Invocation.run());
+}
+
+TEST(ToolInvocation, CC1ArgsInvalid) {
+  llvm::IntrusiveRefCntPtr<llvm::vfs::OverlayFileSystem> OverlayFileSystem(
+      new llvm::vfs::OverlayFileSystem(llvm::vfs::getRealFileSystem()));
+  llvm::IntrusiveRefCntPtr<llvm::vfs::InMemoryFileSystem> InMemoryFileSystem(
+      new llvm::vfs::InMemoryFileSystem);
+  OverlayFileSystem->pushOverlay(InMemoryFileSystem);
+  llvm::IntrusiveRefCntPtr<FileManager> Files(
+      new FileManager(FileSystemOptions(), OverlayFileSystem));
+  std::vector<std::string> Args;
+  Args.push_back("tool-executable");
+  Args.push_back("-cc1");
+  Args.push_back("-invalid-arg");
+  Args.push_back("test.cpp");
+  clang::tooling::ToolInvocation Invocation(
+      Args, std::make_unique<SyntaxOnlyAction>(), Files.get());
+  InMemoryFileSystem->addFile(
+      "test.cpp", 0, llvm::MemoryBuffer::getMemBuffer("void foo(void);\n"));
+  EXPECT_FALSE(Invocation.run());
+}
+
 namespace {
 /// Overlays the real filesystem with the given VFS and returns the result.
 llvm::IntrusiveRefCntPtr<llvm::vfs::OverlayFileSystem>