[analyzer] Introduce "event" mechanism in CheckerManager.

A checker can register as receiver/listener of "events" (basically it registers a callback
with a function getting called with an argument of the event type) and other checkers can
register as "dispatchers" and can pass an event object to all the listeners.
This allows cooperation amongst checkers but with very loose coupling.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@126658 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 117 insertions, 15 deletions

diff --git a/include/clang/StaticAnalyzer/Core/CheckerManager.h b/include/clang/StaticAnalyzer/Core/CheckerManager.h
index 3c23cbd29f..d57b55f5f7 100644
--- a/include/clang/StaticAnalyzer/Core/CheckerManager.h
+++ b/include/clang/StaticAnalyzer/Core/CheckerManager.h
@@ -97,6 +97,8 @@ public:
   CheckerManager(const LangOptions &langOpts) : LangOpts(langOpts) { }
   ~CheckerManager();
 
+  void finishedCheckerRegistration();
+
   const LangOptions &getLangOptions() const { return LangOpts; }
 
   typedef void *CheckerRef;
@@ -112,7 +114,7 @@ public:
   /// \returns a pointer to the checker object.
   template <typename CHECKER>
   CHECKER *registerChecker() {
-    CheckerTag tag = getCheckerTag<CHECKER>();
+    CheckerTag tag = getTag<CHECKER>();
     CheckerRef &ref = CheckerTags[tag];
     if (ref)
       return static_cast<CHECKER *>(ref); // already registered.
@@ -350,6 +352,46 @@ public:
   void _registerForEvalCall(EvalCallFunc checkfn);
 
 //===----------------------------------------------------------------------===//
+// Internal registration functions for events.
+//===----------------------------------------------------------------------===//
+
+  typedef void *EventTag;
+
+  class CheckEventFunc {
+    typedef void (*Func)(void *, const void *);
+    Func Fn;
+  public:
+    void *Checker;
+    CheckEventFunc(void *checker, Func fn)
+      : Fn(fn), Checker(checker) { }
+    void operator()(const void *event) const {
+      return Fn(Checker, event);
+    } 
+  };
+
+  template <typename EVENT>
+  void _registerListenerForEvent(CheckEventFunc checkfn) {
+    EventInfo &info = Events[getTag<EVENT>()];
+    info.Checkers.push_back(checkfn);    
+  }
+
+  template <typename EVENT>
+  void _registerDispatcherForEvent() {
+    EventInfo &info = Events[getTag<EVENT>()];
+    info.HasDispatcher = true;
+  }
+
+  template <typename EVENT>
+  void _dispatchEvent(const EVENT &event) const {
+    EventsTy::const_iterator I = Events.find(getTag<EVENT>());
+    if (I == Events.end())
+      return;
+    const EventInfo &info = I->second;
+    for (unsigned i = 0, e = info.Checkers.size(); i != e; ++i)
+      info.Checkers[i](&event);
+  }
+
+//===----------------------------------------------------------------------===//
 // Implementation details.
 //===----------------------------------------------------------------------===//
 
@@ -357,8 +399,8 @@ private:
   template <typename CHECKER>
   static void destruct(void *obj) { delete static_cast<CHECKER *>(obj); }
 
-  template <typename CHECKER>
-  static CheckerTag getCheckerTag() { static int tag; return &tag; }
+  template <typename T>
+  static void *getTag() { static int tag; return &tag; }
 
   llvm::DenseMap<CheckerTag, CheckerRef> CheckerTags;
 
@@ -439,6 +481,15 @@ private:
   std::vector<EvalAssumeFunc> EvalAssumeCheckers;
 
   std::vector<EvalCallFunc> EvalCallCheckers;
+
+  struct EventInfo {
+    llvm::SmallVector<CheckEventFunc, 4> Checkers;
+    bool HasDispatcher;
+    EventInfo() : HasDispatcher(false) { }
+  };
+  
+  typedef llvm::DenseMap<EventTag, EventInfo> EventsTy;
+  EventsTy Events;
 };
 
 } // end ento namespace
diff --git a/include/clang/StaticAnalyzer/Core/CheckerV2.h b/include/clang/StaticAnalyzer/Core/CheckerV2.h
index 931cee9931..a4c7c7d806 100644
--- a/include/clang/StaticAnalyzer/Core/CheckerV2.h
+++ b/include/clang/StaticAnalyzer/Core/CheckerV2.h
@@ -259,6 +259,20 @@ public:
   }
 };
 
+template <typename EVENT>
+class Event {
+  template <typename CHECKER>
+  static void _checkEvent(void *checker, const void *event) {
+    ((const CHECKER *)checker)->checkEvent(*(const EVENT *)event);
+  }
+public:
+  template <typename CHECKER>
+  static void _register(CHECKER *checker, CheckerManager &mgr) {
+    mgr._registerListenerForEvent<EVENT>(
+                 CheckerManager::CheckEventFunc(checker, _checkEvent<CHECKER>));
+  }
+};
+
 } // end check namespace
 
 namespace eval {
@@ -300,22 +314,47 @@ template <typename CHECK1, typename CHECK2=check::_VoidCheck,
           typename CHECK7=check::_VoidCheck, typename CHECK8=check::_VoidCheck,
           typename CHECK9=check::_VoidCheck, typename CHECK10=check::_VoidCheck,
           typename CHECK11=check::_VoidCheck,typename CHECK12=check::_VoidCheck>
-class CheckerV2 {
+class CheckerV2;
+
+template <>
+class CheckerV2<check::_VoidCheck, check::_VoidCheck, check::_VoidCheck,
+                check::_VoidCheck, check::_VoidCheck, check::_VoidCheck,
+                check::_VoidCheck, check::_VoidCheck, check::_VoidCheck,
+                check::_VoidCheck, check::_VoidCheck, check::_VoidCheck> {
+public:
+  static void _register(void *checker, CheckerManager &mgr) { }
+};
+
+template <typename CHECK1, typename CHECK2, typename CHECK3, typename CHECK4,
+          typename CHECK5, typename CHECK6, typename CHECK7, typename CHECK8,
+          typename CHECK9, typename CHECK10,typename CHECK11,typename CHECK12>
+class CheckerV2
+    : public CHECK1,
+      public CheckerV2<CHECK2, CHECK3, CHECK4, CHECK5, CHECK6, CHECK7, CHECK8,
+                       CHECK9, CHECK10, CHECK11, CHECK12> {
 public:
   template <typename CHECKER>
   static void _register(CHECKER *checker, CheckerManager &mgr) {
     CHECK1::_register(checker, mgr);
-    CHECK2::_register(checker, mgr);
-    CHECK3::_register(checker, mgr);
-    CHECK4::_register(checker, mgr);
-    CHECK5::_register(checker, mgr);
-    CHECK6::_register(checker, mgr);
-    CHECK7::_register(checker, mgr);
-    CHECK8::_register(checker, mgr);
-    CHECK9::_register(checker, mgr);
-    CHECK10::_register(checker, mgr);
-    CHECK11::_register(checker, mgr);
-    CHECK12::_register(checker, mgr);
+    CheckerV2<CHECK2, CHECK3, CHECK4, CHECK5, CHECK6, CHECK7, CHECK8, CHECK9,
+              CHECK10, CHECK11,CHECK12>::_register(checker, mgr);
+  }
+};
+
+template <typename EVENT>
+class EventDispatcher {
+  CheckerManager *Mgr;
+public:
+  EventDispatcher() : Mgr(0) { }
+
+  template <typename CHECKER>
+  static void _register(CHECKER *checker, CheckerManager &mgr) {
+    mgr._registerDispatcherForEvent<EVENT>();
+    static_cast<EventDispatcher<EVENT> *>(checker)->Mgr = &mgr;
+  }
+
+  void dispatchEvent(const EVENT &event) const {
+    Mgr->_dispatchEvent(event);
   }
 };
 
diff --git a/lib/StaticAnalyzer/Core/CheckerManager.cpp b/lib/StaticAnalyzer/Core/CheckerManager.cpp
index 4776f5702d..74f47e4f77 100644
--- a/lib/StaticAnalyzer/Core/CheckerManager.cpp
+++ b/lib/StaticAnalyzer/Core/CheckerManager.cpp
@@ -20,6 +20,16 @@
 using namespace clang;
 using namespace ento;
 
+void CheckerManager::finishedCheckerRegistration() {
+#ifndef NDEBUG
+  // Make sure that for every event that has listeners, there is at least
+  // one dispatcher registered for it.
+  for (llvm::DenseMap<EventTag, EventInfo>::iterator
+         I = Events.begin(), E = Events.end(); I != E; ++I)
+    assert(I->second.HasDispatcher && "No dispatcher registered for an event");
+#endif
+}
+
 //===----------------------------------------------------------------------===//
 // Functions for running checkers for AST traversing..
 //===----------------------------------------------------------------------===//
diff --git a/lib/StaticAnalyzer/Frontend/CheckerRegistration.cpp b/lib/StaticAnalyzer/Frontend/CheckerRegistration.cpp
index 677e20cd9c..0484cbed3b 100644
--- a/lib/StaticAnalyzer/Frontend/CheckerRegistration.cpp
+++ b/lib/StaticAnalyzer/Frontend/CheckerRegistration.cpp
@@ -43,6 +43,8 @@ CheckerManager *ento::registerCheckers(const AnalyzerOptions &opts,
 
   // FIXME: Load CheckerProviders from plugins.
 
+  checkerMgr->finishedCheckerRegistration();
+
   for (unsigned i = 0, e = checkerOpts.size(); i != e; ++i) {
     if (checkerOpts[i].isUnclaimed())
       diags.Report(diag::warn_unkwown_analyzer_checker)