[analyzer] Add very limited support for temporary destructors

This is an improved version of r186498. It enables ExprEngine to reason about
temporary object destructors.  However, these destructor calls are never
inlined, since this feature is still broken. Still, this is sufficient to
properly handle noreturn temporary destructors.

Now, the analyzer correctly handles expressions like "a || A()", and executes the
destructor of "A" only on the paths where "a" evaluted to false.

Temporary destructor processing is still off by default and one has to
explicitly request it by setting cfg-temporary-dtors=true.

Reviewers: jordan_rose

CC: cfe-commits

Differential Revision: http://llvm-reviews.chandlerc.com/D1259

llvm-svn: 189746

1 files changed, 6 insertions, 0 deletions

diff --git a/clang/lib/StaticAnalyzer/Core/ExprEngineCXX.cpp b/clang/lib/StaticAnalyzer/Core/ExprEngineCXX.cpp
index 27963ade934..b128bee1429 100644
--- a/clang/lib/StaticAnalyzer/Core/ExprEngineCXX.cpp
+++ b/clang/lib/StaticAnalyzer/Core/ExprEngineCXX.cpp
@@ -91,6 +91,12 @@ void ExprEngine::performTrivialCopy(NodeBuilder &Bldr, ExplodedNode *Pred,
 /// If the type is not an array type at all, the original value is returned.
 static SVal makeZeroElementRegion(ProgramStateRef State, SVal LValue,
                                   QualType &Ty) {
+  // FIXME: This check is just a temporary workaround, because
+  // ProcessTemporaryDtor sends us NULL regions. It will not be necessary once
+  // we can properly process temporary destructors.
+  if (!LValue.getAsRegion())
+    return LValue;
+
   SValBuilder &SVB = State->getStateManager().getSValBuilder();
   ASTContext &Ctx = SVB.getContext();