Index: include/clang/Frontend/FrontendOptions.h
===================================================================
--- include/clang/Frontend/FrontendOptions.h
+++ include/clang/Frontend/FrontendOptions.h
@@ -81,7 +81,7 @@
   IK_LLVM_IR
 };
 
-  
+
 /// \brief An input file for the front end.
 class FrontendInputFile {
   /// \brief The file name, or "-" to read from standard input.
@@ -109,6 +109,13 @@
   bool isEmpty() const { return File.empty() && Buffer == nullptr; }
   bool isFile() const { return !isBuffer(); }
   bool isBuffer() const { return Buffer != nullptr; }
+  bool isPreprocessed() const {
+    return Kind == IK_PreprocessedC ||
+           Kind == IK_PreprocessedCXX ||
+           Kind == IK_PreprocessedObjC ||
+           Kind == IK_PreprocessedObjCXX ||
+           Kind == IK_PreprocessedCuda;
+  }
 
   StringRef getFile() const {
     assert(isFile());
Index: lib/Frontend/FrontendAction.cpp
===================================================================
--- lib/Frontend/FrontendAction.cpp
+++ lib/Frontend/FrontendAction.cpp
@@ -187,6 +187,55 @@
   return llvm::make_unique<MultiplexConsumer>(std::move(Consumers));
 }
 
+// For preprocessed files, if the first line is the linemarker and specifies
+// the original source file name, use that name as the input file name.
+static bool ReadOriginalFileName(CompilerInstance &CI, std::string *InputFile)
+{
+  bool Invalid = false;
+  auto &SourceMgr = CI.getSourceManager();
+  auto MainFileID = SourceMgr.getMainFileID();
+  const auto *MainFileBuf = SourceMgr.getBuffer(MainFileID, &Invalid);
+  if (Invalid)
+    return false;
+
+  std::unique_ptr<Lexer> RawLexer(
+      new Lexer(MainFileID, MainFileBuf, SourceMgr, CI.getLangOpts()));
+
+  SmallVector<Token, 4> Tokens;
+  Token Result;
+  // Read the first token
+  if (!RawLexer->LexFromRawLexer(Result)) {
+    Tokens.push_back(Result);
+
+    // Push tokens in the first line into the vector
+    while (!RawLexer->LexFromRawLexer(Result)) {
+      if (Result.isAtStartOfLine())
+        break;
+      Tokens.push_back(Result);
+    }
+  }
+
+  // If the first line has the syntax of
+  //
+  // # NUM "FILENAME"
+  //
+  // we use FILENAME as the input file name.
+  if (Tokens.size() >= 3 &&
+      Tokens[0].getKind() == tok::hash &&
+      Tokens[1].getKind() == tok::numeric_constant &&
+      Tokens[2].getKind() == tok::string_literal) {
+    auto OrigFileName
+      = RawLexer->getSpelling(Tokens[2], SourceMgr, CI.getLangOpts(), &Invalid);
+    auto OrigFileNameLen = OrigFileName.size();
+    if (OrigFileName[0] != '\"'  || OrigFileName[OrigFileNameLen-1] != '\"')
+      return false;
+
+    *InputFile = OrigFileName.substr(1, OrigFileNameLen - 2);
+    return true;
+  }
+  return false;
+}
+
 bool FrontendAction::BeginSourceFile(CompilerInstance &CI,
                                      const FrontendInputFile &Input) {
   assert(!Instance && "Already processing a source file!");
@@ -335,6 +384,13 @@
     if (!isModelParsingAction())
       CI.createASTContext();
 
+    // For preprocessed files, check if the first line specifies the original
+    // source file name with a linemarker.
+    std::string OrigFile;
+    if (Input.isPreprocessed())
+      if (ReadOriginalFileName(CI, &OrigFile))
+        InputFile = OrigFile;
+
     std::unique_ptr<ASTConsumer> Consumer =
         CreateWrappedASTConsumer(CI, InputFile);
     if (!Consumer)
@@ -421,9 +477,9 @@
 
   // If there is a layout overrides file, attach an external AST source that
   // provides the layouts from that file.
-  if (!CI.getFrontendOpts().OverrideRecordLayoutsFile.empty() && 
+  if (!CI.getFrontendOpts().OverrideRecordLayoutsFile.empty() &&
       CI.hasASTContext() && !CI.getASTContext().getExternalSource()) {
-    IntrusiveRefCntPtr<ExternalASTSource> 
+    IntrusiveRefCntPtr<ExternalASTSource>
       Override(new LayoutOverrideSource(
                      CI.getFrontendOpts().OverrideRecordLayoutsFile));
     CI.getASTContext().setExternalSource(Override);
Index: test/Frontend/preprocessed-input.c
===================================================================
--- /dev/null
+++ test/Frontend/preprocessed-input.c
@@ -0,0 +1,4 @@
+// RUN: %clang -E -o %t.i %s
+// RUN: %clang -c -o %t.o %t.i
+// RUN: readelf -a --wide %t.o | FileCheck %s
+// CHECK: FILE{{ +}}LOCAL{{ +}}DEFAULT{{ +}}ABS{{.+}}preprocessed-input.c{{$}}