Index: ../llvm/tools/clang/include/clang/Tooling/JSONCompilationDatabase.h
===================================================================
--- ../llvm/tools/clang/include/clang/Tooling/JSONCompilationDatabase.h
+++ ../llvm/tools/clang/include/clang/Tooling/JSONCompilationDatabase.h
@@ -33,18 +33,26 @@
 /// \brief A JSON based compilation database.
 ///
 /// JSON compilation database files must contain a list of JSON objects which
-/// provide the command lines in the attributes 'directory', 'command' and
-/// 'file':
+/// provide the command lines in the attributes 'directory', 'command',
+/// 'arguments' and 'file':
 /// [
 ///   { "directory": "<working directory of the compile>",
 ///     "command": "<compile command line>",
 ///     "file": "<path to source file>"
 ///   },
+///   { "directory": "<working directory of the compile>",
+///     "arguments": ["<raw>", "<command>" "<line>" "<parameters>"],
+///     "file": "<path to source file>"
+///   },
 ///   ...
 /// ]
 /// Each object entry defines one compile action. The specified file is
 /// considered to be the main source file for the translation unit.
 ///
+/// 'command' is a full command line that will be unescaped.
+///
+/// 'arguments' is a list of command line arguments that will not be unescaped.
+///
 /// JSON compilation databases can for example be generated in CMake projects
 /// by setting the flag -DCMAKE_EXPORT_COMPILE_COMMANDS.
 class JSONCompilationDatabase : public CompilationDatabase {
@@ -94,7 +102,7 @@
   // Tuple (directory, commandline) where 'commandline' pointing to the
   // corresponding nodes in the YAML stream.
   typedef std::pair<llvm::yaml::ScalarNode*,
-                    llvm::yaml::ScalarNode*> CompileCommandRef;
+                    std::vector<std::string>> CompileCommandRef;
 
   /// \brief Converts the given array of CompileCommandRefs to CompileCommands.
   void getCommands(ArrayRef<CompileCommandRef> CommandsRef,
Index: ../llvm/tools/clang/lib/Tooling/JSONCompilationDatabase.cpp
===================================================================
--- ../llvm/tools/clang/lib/Tooling/JSONCompilationDatabase.cpp
+++ ../llvm/tools/clang/lib/Tooling/JSONCompilationDatabase.cpp
@@ -221,9 +221,8 @@
     SmallString<8> DirectoryStorage;
     SmallString<1024> CommandStorage;
     Commands.emplace_back(
-        // FIXME: Escape correctly:
-        CommandsRef[I].first->getValue(DirectoryStorage),
-        unescapeCommandLine(CommandsRef[I].second->getValue(CommandStorage)));
+      CommandsRef[I].first->getValue(DirectoryStorage),
+      CommandsRef[I].second);
   }
 }
 
@@ -243,44 +242,66 @@
     ErrorMessage = "Expected array.";
     return false;
   }
-  for (llvm::yaml::SequenceNode::iterator AI = Array->begin(),
-                                          AE = Array->end();
-       AI != AE; ++AI) {
-    llvm::yaml::MappingNode *Object = dyn_cast<llvm::yaml::MappingNode>(&*AI);
+  for (auto& NextObject : *Array) {
+    llvm::yaml::MappingNode *Object = dyn_cast<llvm::yaml::MappingNode>(&NextObject);
     if (!Object) {
       ErrorMessage = "Expected object.";
       return false;
     }
     llvm::yaml::ScalarNode *Directory = nullptr;
-    llvm::yaml::ScalarNode *Command = nullptr;
+    std::vector<std::string> Args;
+    bool CommandFound = false;
     llvm::yaml::ScalarNode *File = nullptr;
-    for (llvm::yaml::MappingNode::iterator KVI = Object->begin(),
-                                           KVE = Object->end();
-         KVI != KVE; ++KVI) {
-      llvm::yaml::Node *Value = (*KVI).getValue();
+    for (auto& NextKeyValue : *Object) {
+      llvm::yaml::ScalarNode *KeyString =
+          dyn_cast<llvm::yaml::ScalarNode>(NextKeyValue.getKey());
+      if (!KeyString) {
+        ErrorMessage = "Expected strings as key.";
+        return false;
+      }
+      SmallString<8> KeyStorage;
+      StringRef KeyValue = KeyString->getValue(KeyStorage);
+      llvm::yaml::Node *Value = NextKeyValue.getValue();
       if (!Value) {
         ErrorMessage = "Expected value.";
         return false;
       }
       llvm::yaml::ScalarNode *ValueString =
           dyn_cast<llvm::yaml::ScalarNode>(Value);
-      if (!ValueString) {
-        ErrorMessage = "Expected string as value.";
+      llvm::yaml::SequenceNode *SequenceString =
+          dyn_cast<llvm::yaml::SequenceNode>(Value);
+      if (KeyValue == "arguments" && !SequenceString) {
+        ErrorMessage = "Expected sequence as value.";
         return false;
-      }
-      llvm::yaml::ScalarNode *KeyString =
-          dyn_cast<llvm::yaml::ScalarNode>((*KVI).getKey());
-      if (!KeyString) {
-        ErrorMessage = "Expected strings as key.";
+      } else if (KeyValue != "arguments" && !ValueString) {
+        ErrorMessage = "Expected string as value.";
         return false;
       }
-      SmallString<8> KeyStorage;
-      if (KeyString->getValue(KeyStorage) == "directory") {
+      if (KeyValue == "directory") {
         Directory = ValueString;
-      } else if (KeyString->getValue(KeyStorage) == "command") {
-        Command = ValueString;
-      } else if (KeyString->getValue(KeyStorage) == "file") {
+      } else if (KeyValue == "command") {
+        if (CommandFound) {
+          ErrorMessage = "Multiple command and arguments found";
+          return false;
+        }
+        SmallString<1024> CommandStorage;
+        // FIXME: Escape correctly:
+        Args = unescapeCommandLine(ValueString->getValue(CommandStorage));
+        CommandFound = true;
+      } else if (KeyValue == "file") {
         File = ValueString;
+      } else if (KeyValue == "arguments") {
+        if (CommandFound) {
+          ErrorMessage = "Multiple command and arguments found";
+          return false;
+        }
+        for (auto& NextArgument : *SequenceString) {
+          SmallString<128> CommandStorage;
+          auto ValueString = dyn_cast<llvm::yaml::ScalarNode>(&NextArgument);
+
+          Args.push_back(ValueString->getValue(CommandStorage));
+        }
+        CommandFound = true;
       } else {
         ErrorMessage = ("Unknown key: \"" +
                         KeyString->getRawValue() + "\"").str();
@@ -291,8 +312,8 @@
       ErrorMessage = "Missing key: \"file\".";
       return false;
     }
-    if (!Command) {
-      ErrorMessage = "Missing key: \"command\".";
+    if (!CommandFound) {
+      ErrorMessage = "Missing key: \"command\" or \"arguments\".";
       return false;
     }
     if (!Directory) {
@@ -312,7 +333,7 @@
       llvm::sys::path::native(FileName, NativeFilePath);
     }
     IndexByFile[NativeFilePath].push_back(
-        CompileCommandRef(Directory, Command));
+        CompileCommandRef(Directory, Args));
     MatchTrie.insert(NativeFilePath);
   }
   return true;
Index: ../llvm/tools/clang/unittests/Tooling/CompilationDatabaseTest.cpp
===================================================================
--- ../llvm/tools/clang/unittests/Tooling/CompilationDatabaseTest.cpp
+++ ../llvm/tools/clang/unittests/Tooling/CompilationDatabaseTest.cpp
@@ -36,8 +36,13 @@
   expectFailure("[{[]:\"\"}]", "Incorrectly typed entry");
   expectFailure("[{}]", "Empty entry");
   expectFailure("[{\"directory\":\"\",\"command\":\"\"}]", "Missing file");
-  expectFailure("[{\"directory\":\"\",\"file\":\"\"}]", "Missing command");
+  expectFailure("[{\"directory\":\"\",\"file\":\"\"}]", "Missing command or arguments");
   expectFailure("[{\"command\":\"\",\"file\":\"\"}]", "Missing directory");
+  expectFailure("[{\"directory\":\"\",\"arguments\":[]}]", "Missing file");
+  expectFailure("[{\"arguments\":\"\",\"file\":\"\"}]", "Missing directory");
+  expectFailure("[{\"command\":\"\",\"arguments\":[],\"file\":\"\"}]", "Command and arguments");
+  expectFailure("[{\"directory\":\"\",\"arguments\":\"\",\"file\":\"\"}]", "Arguments not array");
+  expectFailure("[{\"directory\":\"\",\"command\":[],\"file\":\"\"}]", "Command not string");
 }
 
 static std::vector<std::string> getAllFiles(StringRef JSONDatabase,