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
@@ -224,7 +224,8 @@
     StringRef FileName = "input.cc", StringRef ToolName = "clang-tool",
     std::shared_ptr<PCHContainerOperations> PCHContainerOps =
         std::make_shared<PCHContainerOperations>(),
-    ArgumentsAdjuster Adjuster = getClangStripDependencyFileAdjuster());
+    ArgumentsAdjuster Adjuster = getClangStripDependencyFileAdjuster(),
+    const FileContentMappings &VirtualMappedFiles = FileContentMappings());
 
 /// Utility to run a FrontendAction in a single clang invocation.
 class ToolInvocation {
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
@@ -619,7 +619,7 @@
 std::unique_ptr<ASTUnit> buildASTFromCodeWithArgs(
     StringRef Code, const std::vector<std::string> &Args, StringRef FileName,
     StringRef ToolName, std::shared_ptr<PCHContainerOperations> PCHContainerOps,
-    ArgumentsAdjuster Adjuster) {
+    ArgumentsAdjuster Adjuster, const FileContentMappings &VirtualMappedFiles) {
   std::vector<std::unique_ptr<ASTUnit>> ASTs;
   ASTBuilderAction Action(ASTs);
   llvm::IntrusiveRefCntPtr<llvm::vfs::OverlayFileSystem> OverlayFileSystem(
@@ -636,6 +636,12 @@
 
   InMemoryFileSystem->addFile(FileName, 0,
                               llvm::MemoryBuffer::getMemBufferCopy(Code));
+  for (auto &FilenameWithContent : VirtualMappedFiles) {
+    InMemoryFileSystem->addFile(
+        FilenameWithContent.first, 0,
+        llvm::MemoryBuffer::getMemBuffer(FilenameWithContent.second));
+  }
+
   if (!Invocation.run())
     return nullptr;