1 files changed, 42 insertions, 10 deletions

diff --git a/lib/Frontend/PrintPreprocessedOutput.cpp b/lib/Frontend/PrintPreprocessedOutput.cpp
index 6192554299ab..a58c935620a2 100644
--- a/lib/Frontend/PrintPreprocessedOutput.cpp
+++ b/lib/Frontend/PrintPreprocessedOutput.cpp
@@ -562,8 +562,13 @@ struct UnknownPragmaHandler : public PragmaHandler {
   const char *Prefix;
   PrintPPOutputPPCallbacks *Callbacks;
 
-  UnknownPragmaHandler(const char *prefix, PrintPPOutputPPCallbacks *callbacks)
-    : Prefix(prefix), Callbacks(callbacks) {}
+  // Set to true if tokens should be expanded
+  bool ShouldExpandTokens;
+
+  UnknownPragmaHandler(const char *prefix, PrintPPOutputPPCallbacks *callbacks,
+                       bool RequireTokenExpansion)
+      : Prefix(prefix), Callbacks(callbacks),
+        ShouldExpandTokens(RequireTokenExpansion) {}
   void HandlePragma(Preprocessor &PP, PragmaIntroducerKind Introducer,
                     Token &PragmaTok) override {
     // Figure out what line we went to and insert the appropriate number of
@@ -571,16 +576,24 @@ struct UnknownPragmaHandler : public PragmaHandler {
     Callbacks->startNewLineIfNeeded();
     Callbacks->MoveToLine(PragmaTok.getLocation());
     Callbacks->OS.write(Prefix, strlen(Prefix));
+
+    Token PrevToken;
+    Token PrevPrevToken;
+    PrevToken.startToken();
+    PrevPrevToken.startToken();
+
     // Read and print all of the pragma tokens.
     while (PragmaTok.isNot(tok::eod)) {
-      if (PragmaTok.hasLeadingSpace())
+      if (PragmaTok.hasLeadingSpace() ||
+          Callbacks->AvoidConcat(PrevPrevToken, PrevToken, PragmaTok))
         Callbacks->OS << ' ';
       std::string TokSpell = PP.getSpelling(PragmaTok);
       Callbacks->OS.write(&TokSpell[0], TokSpell.size());
 
-      // Expand macros in pragmas with -fms-extensions.  The assumption is that
-      // the majority of pragmas in such a file will be Microsoft pragmas.
-      if (PP.getLangOpts().MicrosoftExt)
+      PrevPrevToken = PrevToken;
+      PrevToken = PragmaTok;
+
+      if (ShouldExpandTokens)
         PP.Lex(PragmaTok);
       else
         PP.LexUnexpandedToken(PragmaTok);
@@ -718,10 +731,29 @@ void clang::DoPrintPreprocessedInput(Preprocessor &PP, raw_ostream *OS,
 
   PrintPPOutputPPCallbacks *Callbacks = new PrintPPOutputPPCallbacks(
       PP, *OS, !Opts.ShowLineMarkers, Opts.ShowMacros, Opts.UseLineDirectives);
-  PP.AddPragmaHandler(new UnknownPragmaHandler("#pragma", Callbacks));
-  PP.AddPragmaHandler("GCC", new UnknownPragmaHandler("#pragma GCC",Callbacks));
-  PP.AddPragmaHandler("clang",
-                      new UnknownPragmaHandler("#pragma clang", Callbacks));
+
+  // Expand macros in pragmas with -fms-extensions.  The assumption is that
+  // the majority of pragmas in such a file will be Microsoft pragmas.
+  PP.AddPragmaHandler(new UnknownPragmaHandler(
+      "#pragma", Callbacks,
+      /*RequireTokenExpansion=*/PP.getLangOpts().MicrosoftExt));
+  PP.AddPragmaHandler(
+      "GCC", new UnknownPragmaHandler(
+                 "#pragma GCC", Callbacks,
+                 /*RequireTokenExpansion=*/PP.getLangOpts().MicrosoftExt));
+  PP.AddPragmaHandler(
+      "clang", new UnknownPragmaHandler(
+                   "#pragma clang", Callbacks,
+                   /*RequireTokenExpansion=*/PP.getLangOpts().MicrosoftExt));
+
+  // The tokens after pragma omp need to be expanded.
+  //
+  //  OpenMP [2.1, Directive format]
+  //  Preprocessing tokens following the #pragma omp are subject to macro
+  //  replacement.
+  PP.AddPragmaHandler("omp",
+                      new UnknownPragmaHandler("#pragma omp", Callbacks,
+                                               /*RequireTokenExpansion=*/true));
 
   PP.addPPCallbacks(std::unique_ptr<PPCallbacks>(Callbacks));