Index: lib/Tooling/CommonOptionsParser.cpp
===================================================================
--- lib/Tooling/CommonOptionsParser.cpp
+++ lib/Tooling/CommonOptionsParser.cpp
@@ -25,6 +25,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/Support/CommandLine.h"
+#include "llvm/Support/StringSaver.h"
 #include "clang/Tooling/ArgumentsAdjusters.h"
 #include "clang/Tooling/CommonOptionsParser.h"
 #include "clang/Tooling/Tooling.h"
@@ -115,6 +116,14 @@
       cl::cat(Category));
 
   cl::HideUnrelatedOptions(Category);
+  
+  // Expand response files before loading compilation database from command line
+  SmallVector<const char *, 20> newArgv(argv, argv + argc);
+  BumpPtrAllocator A;
+  StringSaver Saver(A);
+  cl::ExpandResponseFiles(Saver, cl::TokenizeGNUCommandLine, newArgv);
+  argv = &newArgv[0];
+  argc = static_cast<int>(newArgv.size());
 
   std::string ErrorMessage;
   Compilations =
Index: unittests/Tooling/CompilationDatabaseTest.cpp
===================================================================
--- unittests/Tooling/CompilationDatabaseTest.cpp
+++ unittests/Tooling/CompilationDatabaseTest.cpp
@@ -10,12 +10,16 @@
 #include "clang/AST/DeclCXX.h"
 #include "clang/AST/DeclGroup.h"
 #include "clang/Frontend/FrontendAction.h"
+#include "clang/Tooling/CommonOptionsParser.h"
 #include "clang/Tooling/FileMatchTrie.h"
 #include "clang/Tooling/JSONCompilationDatabase.h"
 #include "clang/Tooling/Tooling.h"
+#include "llvm/Support/FileSystem.h"
 #include "llvm/Support/Path.h"
 #include "gtest/gtest.h"
 
+#include <fstream>
+
 namespace clang {
 namespace tooling {
 
@@ -626,5 +630,52 @@
   EXPECT_EQ(2, Argc);
 }
 
+class ParseCompilationDatabaseFromResponseFileTest : public testing::Test {
+public:
+  SmallString<128> TestDir;
+  SmallString<128> ResponseFileName;
+
+  ParseCompilationDatabaseFromResponseFileTest() {
+    std::error_code EC = llvm::sys::fs::createUniqueDirectory("unittest", TestDir);
+    EXPECT_TRUE(!EC);
+    llvm::sys::path::append(ResponseFileName, TestDir, "resp");
+  }
+  void setResponseFileContent(const std::string &content) {
+    std::ofstream File(ResponseFileName.c_str());
+    EXPECT_TRUE(File.is_open());
+    File << content;
+    File.close();
+  }
+  ~ParseCompilationDatabaseFromResponseFileTest() override {
+    llvm::sys::fs::remove(ResponseFileName);
+    llvm::sys::fs::remove(TestDir);
+  }
+};
+
+TEST_F(ParseCompilationDatabaseFromResponseFileTest, GetCompileCommands) {
+  setResponseFileContent("-- -a=true -b");
+  SmallString<128> ResponseRef;
+  ResponseRef.append(1, '@');
+  ResponseRef.append(ResponseFileName.c_str());
+  int Argc = 3;
+  const char *Argv[] = { "1", "2", ResponseRef.c_str() };
+  llvm::cl::OptionCategory Category("options");
+  llvm::cl::opt<bool> option1("a", llvm::cl::desc(""), llvm::cl::init(false),
+                              llvm::cl::cat(Category));
+  llvm::cl::opt<bool> option2("b", llvm::cl::desc(""), llvm::cl::init(false),
+                              llvm::cl::cat(Category));
+  CommonOptionsParser Parser(Argc, Argv, Category);
+  CompilationDatabase &Database = Parser.getCompilations();
+  std::vector<CompileCommand> ActualCC = Database.getCompileCommands("source");
+  ASSERT_EQ(1u, ActualCC.size());
+  std::vector<std::string> ExpectedCmd;
+  ExpectedCmd.push_back("clang-tool");
+  ExpectedCmd.push_back("-a=true");
+  ExpectedCmd.push_back("-b");
+  ExpectedCmd.push_back("source");
+
+  ASSERT_EQ(ExpectedCmd, ActualCC[0].CommandLine);
+}
+
 } // end namespace tooling
 } // end namespace clang