[analyzer] Add a CFG node for the allocator call in a C++ 'new' expression.

In an expression like "new (a, b) Foo(x, y)", two things happen:
- Memory is allocated by calling a function named 'operator new'.
- The memory is initialized using the constructor for 'Foo'.

Currently the analyzer only models the second event, though it has special
cases for both the default and placement forms of operator new. This patch
is the first step towards properly modeling both events: it changes the CFG
so that the above expression now generates the following elements.

1. a
2. b
3. (CFGNewAllocator)
4. x
5. y
6. Foo::Foo

The analyzer currently ignores the CFGNewAllocator element, but the next
step is to treat that as a call like any other.

The CFGNewAllocator element is not added to the CFG for analysis-based
warnings, since none of them take advantage of it yet.

llvm-svn: 199123

1 files changed, 15 insertions, 0 deletions

diff --git a/clang/lib/StaticAnalyzer/Core/ExprEngine.cpp b/clang/lib/StaticAnalyzer/Core/ExprEngine.cpp
index ad97801cc0e..095e09795da 100644
--- a/clang/lib/StaticAnalyzer/Core/ExprEngine.cpp
+++ b/clang/lib/StaticAnalyzer/Core/ExprEngine.cpp
@@ -286,6 +286,10 @@ void ExprEngine::processCFGElement(const CFGElement E, ExplodedNode *Pred,
     case CFGElement::Initializer:
       ProcessInitializer(E.castAs<CFGInitializer>().getInitializer(), Pred);
       return;
+    case CFGElement::NewAllocator:
+      ProcessNewAllocator(E.castAs<CFGNewAllocator>().getAllocatorExpr(),
+                          Pred);
+      return;
     case CFGElement::AutomaticObjectDtor:
     case CFGElement::DeleteDtor:
     case CFGElement::BaseDtor:
@@ -547,6 +551,17 @@ void ExprEngine::ProcessImplicitDtor(const CFGImplicitDtor D,
   Engine.enqueue(Dst, currBldrCtx->getBlock(), currStmtIdx);
 }
 
+void ExprEngine::ProcessNewAllocator(const CXXNewExpr *NE,
+                                     ExplodedNode *Pred) {
+  //TODO: Implement VisitCXXNewAllocatorCall
+  ExplodedNodeSet Dst;
+  NodeBuilder Bldr(Pred, Dst, *currBldrCtx);
+  const LocationContext *LCtx = Pred->getLocationContext();
+  PostImplicitCall PP(NE->getOperatorNew(), NE->getLocStart(), LCtx);
+  Bldr.generateNode(PP, Pred->getState(), Pred);
+  Engine.enqueue(Dst, currBldrCtx->getBlock(), currStmtIdx);
+}
+
 void ExprEngine::ProcessAutomaticObjDtor(const CFGAutomaticObjDtor Dtor,
                                          ExplodedNode *Pred,
                                          ExplodedNodeSet &Dst) {