[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.

llvm-svn: 160983

1 files changed, 14 insertions, 0 deletions

diff --git a/clang/lib/StaticAnalyzer/Core/ProgramState.cpp b/clang/lib/StaticAnalyzer/Core/ProgramState.cpp
index 529be0a845f..6adc18c67ce 100644
--- a/clang/lib/StaticAnalyzer/Core/ProgramState.cpp
+++ b/clang/lib/StaticAnalyzer/Core/ProgramState.cpp
@@ -12,6 +12,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "clang/Analysis/CFG.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h"
 #include "clang/StaticAnalyzer/Core/PathSensitive/ProgramStateTrait.h"
 #include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h"
 #include "clang/StaticAnalyzer/Core/PathSensitive/SubEngine.h"
@@ -70,6 +71,19 @@ ProgramState::~ProgramState() {
     stateMgr->getStoreManager().decrementReferenceCount(store);
 }
 
+ProgramStateManager::ProgramStateManager(ASTContext &Ctx,
+                                         StoreManagerCreator CreateSMgr,
+                                         ConstraintManagerCreator CreateCMgr,
+                                         llvm::BumpPtrAllocator &alloc,
+                                         SubEngine &SubEng)
+  : Eng(&SubEng), EnvMgr(alloc), GDMFactory(alloc),
+    svalBuilder(createSimpleSValBuilder(alloc, Ctx, *this)),
+    CallEventMgr(new CallEventManager(alloc)), Alloc(alloc) {
+  StoreMgr.reset((*CreateSMgr)(*this));
+  ConstraintMgr.reset((*CreateCMgr)(*this, SubEng));
+}
+
+
 ProgramStateManager::~ProgramStateManager() {
   for (GDMContextsTy::iterator I=GDMContexts.begin(), E=GDMContexts.end();
        I!=E; ++I)