1 files changed, 37 insertions, 1 deletions
diff --git a/clang/examples/AnnotateFunctions/AnnotateFunctions.cpp b/clang/examples/AnnotateFunctions/AnnotateFunctions.cpp
index f2e7322183a..375f18f8e09 100644
--- a/clang/examples/AnnotateFunctions/AnnotateFunctions.cpp
+++ b/clang/examples/AnnotateFunctions/AnnotateFunctions.cpp
@@ -7,20 +7,29 @@
 //
 //===----------------------------------------------------------------------===//
 //
-// Example clang plugin which adds an annotation to every function.
+// Example clang plugin which adds an annotation to every function in
+// translation units that start with #pragma enable_annotate.
 //
 //===----------------------------------------------------------------------===//
 
 #include "clang/Frontend/FrontendPluginRegistry.h"
 #include "clang/AST/AST.h"
 #include "clang/AST/ASTConsumer.h"
+#include "clang/Lex/Preprocessor.h"
+#include "clang/Lex/LexDiagnostic.h"
 using namespace clang;
 
 namespace {
 
+static bool EnableAnnotate = false;
+static bool HandledDecl = false;
+
 class AnnotateFunctionsConsumer : public ASTConsumer {
 public:
   bool HandleTopLevelDecl(DeclGroupRef DG) override {
+    HandledDecl = true;
+    if (!EnableAnnotate)
+      return true;
     for (auto D : DG)
       if (FunctionDecl *FD = dyn_cast<FunctionDecl>(D))
         FD->addAttr(AnnotateAttr::CreateImplicit(FD->getASTContext(),
@@ -46,7 +55,34 @@ public:
   }
 };
 
+class PragmaAnnotateHandler : public PragmaHandler {
+public:
+  PragmaAnnotateHandler() : PragmaHandler("enable_annotate") { }
+
+  void HandlePragma(Preprocessor &PP, PragmaIntroducerKind Introducer,
+                    Token &PragmaTok) override {
+
+    Token Tok;
+    PP.LexUnexpandedToken(Tok);
+    if (Tok.isNot(tok::eod))
+      PP.Diag(Tok, diag::ext_pp_extra_tokens_at_eol) << "pragma";
+
+    if (HandledDecl) {
+      DiagnosticsEngine &D = PP.getDiagnostics();
+      unsigned ID = D.getCustomDiagID(
+        DiagnosticsEngine::Error,
+        "#pragma enable_annotate not allowed after declarations");
+      D.Report(PragmaTok.getLocation(), ID);
+    }
+
+    EnableAnnotate = true;
+  }
+};
+
 }
 
 static FrontendPluginRegistry::Add<AnnotateFunctionsAction>
 X("annotate-fns", "annotate functions");
+
+static PragmaHandlerRegistry::Add<PragmaAnnotateHandler>
+Y("enable_annotate","enable annotation");