Make it possible for AST plugins to enable themselves by default

Currently when an AST plugin is loaded it must then be enabled by passing
-plugin pluginname or -add-plugin pluginname to the -cc1 command line. This
patch adds a method to PluginASTAction which allows it to declare that the
action happens before, instead of, or after the main AST action, plus the
relevant changes to make the plugin action happen at that time automatically.

Differential Revision: http://reviews.llvm.org/D17959

llvm-svn: 263546

1 files changed, 52 insertions, 0 deletions

diff --git a/clang/examples/AnnotateFunctions/AnnotateFunctions.cpp b/clang/examples/AnnotateFunctions/AnnotateFunctions.cpp
new file mode 100644
index 00000000000..f2e7322183a
--- /dev/null
+++ b/clang/examples/AnnotateFunctions/AnnotateFunctions.cpp
@@ -0,0 +1,52 @@
+//===- AnnotateFunctions.cpp ----------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// Example clang plugin which adds an annotation to every function.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Frontend/FrontendPluginRegistry.h"
+#include "clang/AST/AST.h"
+#include "clang/AST/ASTConsumer.h"
+using namespace clang;
+
+namespace {
+
+class AnnotateFunctionsConsumer : public ASTConsumer {
+public:
+  bool HandleTopLevelDecl(DeclGroupRef DG) override {
+    for (auto D : DG)
+      if (FunctionDecl *FD = dyn_cast<FunctionDecl>(D))
+        FD->addAttr(AnnotateAttr::CreateImplicit(FD->getASTContext(),
+                                                 "example_annotation"));
+    return true;
+  }
+};
+
+class AnnotateFunctionsAction : public PluginASTAction {
+public:
+  std::unique_ptr<ASTConsumer> CreateASTConsumer(CompilerInstance &CI,
+                                                 llvm::StringRef) override {
+    return llvm::make_unique<AnnotateFunctionsConsumer>();
+  }
+
+  bool ParseArgs(const CompilerInstance &CI,
+                 const std::vector<std::string> &args) override {
+    return true;
+  }
+
+  PluginASTAction::ActionType getActionType() override {
+    return AddBeforeMainAction;
+  }
+};
+
+}
+
+static FrontendPluginRegistry::Add<AnnotateFunctionsAction>
+X("annotate-fns", "annotate functions");