diff --git a/clang/include/clang/Tooling/CompilationDatabase.h b/clang/include/clang/Tooling/CompilationDatabase.h
--- a/clang/include/clang/Tooling/CompilationDatabase.h
+++ b/clang/include/clang/Tooling/CompilationDatabase.h
@@ -31,6 +31,7 @@
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/Twine.h"
+#include "llvm/Support/VirtualFileSystem.h"
 #include <memory>
 #include <string>
 #include <utility>
@@ -219,6 +220,12 @@
 std::unique_ptr<CompilationDatabase>
 inferTargetAndDriverMode(std::unique_ptr<CompilationDatabase> Base);
 
+/// Returns a wrapped CompilationDatabase that will expand all rsp(response)
+/// files on commandline returned by underlying database.
+std::unique_ptr<CompilationDatabase>
+expandResponseFiles(std::unique_ptr<CompilationDatabase> Base,
+                    llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> FS);
+
 } // namespace tooling
 } // namespace clang
 
diff --git a/clang/lib/Tooling/CMakeLists.txt b/clang/lib/Tooling/CMakeLists.txt
--- a/clang/lib/Tooling/CMakeLists.txt
+++ b/clang/lib/Tooling/CMakeLists.txt
@@ -17,6 +17,7 @@
   CommonOptionsParser.cpp
   CompilationDatabase.cpp
   Execution.cpp
+  ExpandResponseFilesCompilationDatabase.cpp
   FileMatchTrie.cpp
   FixIt.cpp
   GuessTargetAndModeCompilationDatabase.cpp
diff --git a/clang/lib/Tooling/ExpandResponseFilesCompilationDatabase.cpp b/clang/lib/Tooling/ExpandResponseFilesCompilationDatabase.cpp
new file mode 100644
--- /dev/null
+++ b/clang/lib/Tooling/ExpandResponseFilesCompilationDatabase.cpp
@@ -0,0 +1,92 @@
+//===- ExpandResponseFileCompilationDataBase.cpp --------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Tooling/CompilationDatabase.h"
+#include "llvm/ADT/Triple.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/ConvertUTF.h"
+#include "llvm/Support/ErrorOr.h"
+#include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/Path.h"
+#include "llvm/Support/StringSaver.h"
+
+namespace clang {
+namespace tooling {
+namespace {
+
+class ExpandResponseFilesDatabase : public CompilationDatabase {
+public:
+  ExpandResponseFilesDatabase(
+      std::unique_ptr<CompilationDatabase> Base,
+      llvm::cl::TokenizerCallback Tokenizer,
+      llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> FS)
+      : Base(std::move(Base)), Tokenizer(Tokenizer), FS(FS) {
+    assert(this->Base != nullptr);
+    assert(this->Tokenizer != nullptr);
+    assert(this->FS != nullptr);
+  }
+
+  std::vector<std::string> getAllFiles() const override {
+    return Base->getAllFiles();
+  }
+
+  std::vector<CompileCommand>
+  getCompileCommands(StringRef FilePath) const override {
+    return expand(Base->getCompileCommands(FilePath));
+  }
+
+  std::vector<CompileCommand> getAllCompileCommands() const override {
+    return expand(Base->getAllCompileCommands());
+  }
+
+private:
+  std::vector<CompileCommand> expand(std::vector<CompileCommand> Cmds) const {
+    llvm::ErrorOr<std::string> PreWorkingDirectory =
+        FS->getCurrentWorkingDirectory();
+    for (auto &Cmd : Cmds) {
+      bool SeenRSPFile = false;
+      llvm::SmallVector<const char *, 20> Argv;
+      Argv.reserve(Cmd.CommandLine.size());
+      for (auto &Arg : Cmd.CommandLine) {
+        Argv.push_back(Arg.c_str());
+        SeenRSPFile |= Arg.front() == '@';
+      }
+      if (!SeenRSPFile)
+        continue;
+      if (FS->setCurrentWorkingDirectory(Cmd.Directory))
+        continue;
+      llvm::BumpPtrAllocator Alloc;
+      llvm::StringSaver Saver(Alloc);
+      llvm::cl::ExpandResponseFiles(Saver, Tokenizer, Argv, false, false, *FS);
+      Cmd.CommandLine.assign(Argv.begin(), Argv.end());
+    }
+    if (PreWorkingDirectory)
+      FS->setCurrentWorkingDirectory(*PreWorkingDirectory);
+    return Cmds;
+  }
+
+private:
+  std::unique_ptr<CompilationDatabase> Base;
+  llvm::cl::TokenizerCallback Tokenizer;
+  llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> FS;
+};
+
+} // namespace
+
+std::unique_ptr<CompilationDatabase>
+expandResponseFiles(std::unique_ptr<CompilationDatabase> Base,
+                    llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> FS) {
+  auto Tokenizer = llvm::Triple(llvm::sys::getProcessTriple()).isOSWindows()
+                       ? llvm::cl::TokenizeWindowsCommandLine
+                       : llvm::cl::TokenizeGNUCommandLine;
+  return std::make_unique<ExpandResponseFilesDatabase>(std::move(Base),
+                                                       Tokenizer, FS);
+}
+
+} // namespace tooling
+} // namespace clang
diff --git a/clang/lib/Tooling/JSONCompilationDatabase.cpp b/clang/lib/Tooling/JSONCompilationDatabase.cpp
--- a/clang/lib/Tooling/JSONCompilationDatabase.cpp
+++ b/clang/lib/Tooling/JSONCompilationDatabase.cpp
@@ -168,7 +168,8 @@
     auto Base = JSONCompilationDatabase::loadFromFile(
         JSONDatabasePath, ErrorMessage, JSONCommandLineSyntax::AutoDetect);
     return Base ? inferTargetAndDriverMode(
-                      inferMissingCompileCommands(std::move(Base)))
+                      inferMissingCompileCommands(expandResponseFiles(
+                          std::move(Base), llvm::vfs::getRealFileSystem())))
                 : nullptr;
   }
 };
diff --git a/clang/unittests/Tooling/CompilationDatabaseTest.cpp b/clang/unittests/Tooling/CompilationDatabaseTest.cpp
--- a/clang/unittests/Tooling/CompilationDatabaseTest.cpp
+++ b/clang/unittests/Tooling/CompilationDatabaseTest.cpp
@@ -859,5 +859,64 @@
             "clang++ --driver-mode=g++ bar.cpp -D bar.cpp");
 }
 
+class ExpandResponseFilesTest : public MemDBTest {
+protected:
+  void SetUp() override {
+    FS = new llvm::vfs::InMemoryFileSystem;
+    
+    InnerDir = path(StringRef("inner"));
+
+    llvm::sys::path::append(RspFileName1, InnerDir, "rsp1.rsp");
+    addFile(RspFileName1, "-Dflag1");
+
+    RspFileName2 = path(StringRef("rsp2.rsp"));
+    addFile(RspFileName2, "-Dflag2 @rsp3.rsp");
+
+    RspFileName3 = path(StringRef("rsp3.rsp"));
+    addFile(RspFileName3, "-Dflag3");
+
+    RspFileName4 = path(StringRef("rsp4.rsp"));
+    addFile(RspFileName4, "-Dflag4 @rsp4.rsp");
+
+    llvm::sys::path::append(RspFileName5, InnerDir, "rsp5.rsp");
+    addFile(RspFileName5, "-Dflag5 @inner/rsp1.rsp");
+  }
+
+  void addFile(StringRef File, StringRef Context) {
+    ASSERT_TRUE(FS->addFile(File, 0, llvm::MemoryBuffer::getMemBufferCopy(Context)));
+  }
+
+  std::string getCommand(llvm::StringRef F) {
+    auto Results = expandResponseFiles(std::make_unique<MemCDB>(Entries),
+                                       FS)
+                       ->getCompileCommands(path(F));
+    if (Results.empty()) {
+      return "none";
+    }
+    return llvm::join(Results[0].CommandLine, " ");
+  }
+
+  SmallString<128> InnerDir;
+  SmallString<128> RspFileName1;
+  SmallString<128> RspFileName2;
+  SmallString<128> RspFileName3;
+  SmallString<128> RspFileName4;
+  SmallString<128> RspFileName5;
+  llvm::IntrusiveRefCntPtr<llvm::vfs::InMemoryFileSystem> FS;
+
+};
+
+TEST_F(ExpandResponseFilesTest, ExpandResponseFiles) {
+  // clang-format off
+  add("foo.cpp", "clang",
+      ("@inner/rsp1.rsp @rsp2.rsp @rsp4.rsp "
+        "@" + RspFileName1 + " @inner/rsp5.rsp @rsp6.rsp")
+          .str());
+  // clang-format on
+  EXPECT_EQ(getCommand("foo.cpp"), "clang foo.cpp -D foo.cpp -Dflag1 -Dflag2 "
+                                   "-Dflag3 -Dflag4 @rsp4.rsp -Dflag1 "
+                                   "-Dflag5 -Dflag1 @rsp6.rsp");
+}
+
 } // end namespace tooling
 } // end namespace clang