diff --git a/clang/lib/Tooling/CompilationDatabase.cpp b/clang/lib/Tooling/CompilationDatabase.cpp
index c87833fba63b..227fa82926c3 100644
--- a/clang/lib/Tooling/CompilationDatabase.cpp
+++ b/clang/lib/Tooling/CompilationDatabase.cpp
@@ -179,8 +179,10 @@ JSONCompilationDatabase::loadFromBuffer(StringRef DatabaseString,
 
 std::vector<CompileCommand>
 JSONCompilationDatabase::getCompileCommands(StringRef FilePath) const {
+  llvm::SmallString<128> NativeFilePath;
+  llvm::sys::path::native(FilePath, NativeFilePath);
   llvm::StringMap< std::vector<CompileCommandRef> >::const_iterator
-    CommandsRefI = IndexByFile.find(FilePath);
+    CommandsRefI = IndexByFile.find(NativeFilePath);
   if (CommandsRefI == IndexByFile.end())
     return std::vector<CompileCommand>();
   const std::vector<CompileCommandRef> &CommandsRef = CommandsRefI->getValue();
@@ -271,7 +273,9 @@ bool JSONCompilationDatabase::parse(std::string &ErrorMessage) {
       return false;
     }
     llvm::SmallString<8> FileStorage;
-    IndexByFile[File->getValue(FileStorage)].push_back(
+    llvm::SmallString<128> NativeFilePath;
+    llvm::sys::path::native(File->getValue(FileStorage), NativeFilePath);
+    IndexByFile[NativeFilePath].push_back(
       CompileCommandRef(Directory, Command));
   }
   return true;
diff --git a/clang/lib/Tooling/Tooling.cpp b/clang/lib/Tooling/Tooling.cpp
index abd670380e9d..a4a63e249f86 100644
--- a/clang/lib/Tooling/Tooling.cpp
+++ b/clang/lib/Tooling/Tooling.cpp
@@ -142,17 +142,21 @@ bool runToolOnCode(clang::FrontendAction *ToolAction, const Twine &Code,
 /// \param BaseDirectory An absolute path.
 static std::string getAbsolutePath(
     StringRef File, StringRef BaseDirectory) {
+  SmallString<1024> PathStorage;
   assert(llvm::sys::path::is_absolute(BaseDirectory));
   if (llvm::sys::path::is_absolute(File)) {
-    return File;
+    llvm::sys::path::native(File, PathStorage);
+    return PathStorage.str();
   }
   StringRef RelativePath(File);
+  // FIXME: Should '.\\' be accepted on Win32?
   if (RelativePath.startswith("./")) {
     RelativePath = RelativePath.substr(strlen("./"));
   }
   llvm::SmallString<1024> AbsolutePath(BaseDirectory);
   llvm::sys::path::append(AbsolutePath, RelativePath);
-  return AbsolutePath.str();
+  llvm::sys::path::native(Twine(AbsolutePath), PathStorage);
+  return PathStorage.str();
 }
 
 ToolInvocation::ToolInvocation(