[analyzer] Introduce a CallEventManager to keep a pool of CallEvents.

This allows us to get around the C++ "virtual constructor" problem
when we'd like to create a CallEvent from an ExplodedNode, an inlined
StackFrameContext, or another CallEvent. The solution has three parts:

- CallEventManager uses a BumpPtrAllocator to allocate CallEvent-sized
  memory blocks. It also keeps a cache of freed CallEvents for reuse.
- CallEvents all have protected copy constructors, along with cloneTo()
  methods that use placement new to copy into CallEventManager-managed
  memory, vtables intact.
- CallEvents owned by CallEventManager are now wrapped in an
  IntrusiveRefCntPtr. Going forwards, it's probably a good idea to create
  ALL CallEvents through the CallEventManager, so that we don't accidentally
  try to reclaim a stack-allocated CallEvent.

All of this machinery is currently unused but will be put into use shortly.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@160983 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 7 insertions, 22 deletions

diff --git a/include/clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h b/include/clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h
index b49e8e3bf8..0d1579f368 100644
--- a/include/clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h
+++ b/include/clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h
@@ -36,6 +36,7 @@ class ASTContext;
 namespace ento {
 
 class CallEvent;
+class CallEventManager;
 
 typedef ConstraintManager* (*ConstraintManagerCreator)(ProgramStateManager&,
                                                        SubEngine&);
@@ -414,6 +415,9 @@ private:
   /// Object that manages the data for all created SVals.
   OwningPtr<SValBuilder> svalBuilder;
 
+  /// Manages memory for created CallEvents.
+  OwningPtr<CallEventManager> CallEventMgr;
+
   /// A BumpPtrAllocator to allocate states.
   llvm::BumpPtrAllocator &Alloc;
   
@@ -425,28 +429,7 @@ public:
                  StoreManagerCreator CreateStoreManager,
                  ConstraintManagerCreator CreateConstraintManager,
                  llvm::BumpPtrAllocator& alloc,
-                 SubEngine &subeng)
-    : Eng(&subeng),
-      EnvMgr(alloc),
-      GDMFactory(alloc),
-      svalBuilder(createSimpleSValBuilder(alloc, Ctx, *this)),
-      Alloc(alloc) {
-    StoreMgr.reset((*CreateStoreManager)(*this));
-    ConstraintMgr.reset((*CreateConstraintManager)(*this, subeng));
-  }
-
-  ProgramStateManager(ASTContext &Ctx,
-                 StoreManagerCreator CreateStoreManager,
-                 ConstraintManager* ConstraintManagerPtr,
-                 llvm::BumpPtrAllocator& alloc)
-    : Eng(0),
-      EnvMgr(alloc),
-      GDMFactory(alloc),
-      svalBuilder(createSimpleSValBuilder(alloc, Ctx, *this)),
-      Alloc(alloc) {
-    StoreMgr.reset((*CreateStoreManager)(*this));
-    ConstraintMgr.reset(ConstraintManagerPtr);
-  }
+                 SubEngine &subeng);
 
   ~ProgramStateManager();
 
@@ -482,6 +465,8 @@ public:
     return svalBuilder->getRegionManager();
   }
 
+  CallEventManager &getCallEventManager() { return *CallEventMgr; }
+
   StoreManager& getStoreManager() { return *StoreMgr; }
   ConstraintManager& getConstraintManager() { return *ConstraintMgr; }
   SubEngine* getOwningEngine() { return Eng; }