[analyzer] Follow up to r167762 - precisely determine the adjustment

conditions.

The adjustment is needed only in case of dynamic dispatch performed by
the analyzer - when the runtime declaration is different from the static
one.

Document this explicitly in the code (by adding a helper). Also, use
canonical Decls to avoid matching against the case where the definition
is different from found declaration.

This fix suppresses the testcase I added in r167762, so add another
testcase to make sure we do test commit r167762.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@167780 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 13 insertions, 3 deletions

diff --git a/lib/StaticAnalyzer/Core/ExprEngineCallAndReturn.cpp b/lib/StaticAnalyzer/Core/ExprEngineCallAndReturn.cpp
index 5b88a45495..2e47a9a61c 100644
--- a/lib/StaticAnalyzer/Core/ExprEngineCallAndReturn.cpp
+++ b/lib/StaticAnalyzer/Core/ExprEngineCallAndReturn.cpp
@@ -191,6 +191,15 @@ void ExprEngine::removeDeadOnEndOfFunction(NodeBuilderContext& BC,
   currBldrCtx = 0;
 }
 
+static bool isDifferentDeclUsedAtRuntime(CallEventRef<> Call,
+    const StackFrameContext *calleeCtx) {
+  const Decl *RuntimeCallee = calleeCtx->getDecl();
+  const Decl *StaticDecl = Call->getDecl();
+  if (!RuntimeCallee || !StaticDecl)
+    return false;
+  return RuntimeCallee->getCanonicalDecl() != StaticDecl->getCanonicalDecl();
+}
+
 /// The call exit is simulated with a sequence of nodes, which occur between 
 /// CallExitBegin and CallExitEnd. The following operations occur between the 
 /// two program points:
@@ -230,9 +239,10 @@ void ExprEngine::processCallExit(ExplodedNode *CEBNode) {
       const LocationContext *LCtx = CEBNode->getLocationContext();
       SVal V = state->getSVal(RS, LCtx);
 
-      const Decl *Callee = calleeCtx->getDecl();
-      if (Callee != Call->getDecl()) {
-        QualType ReturnedTy = CallEvent::getDeclaredResultType(Callee);
+      // Ensure that the return type matches the type of the returned Expr.
+      if (isDifferentDeclUsedAtRuntime(Call, calleeCtx)) {
+        QualType ReturnedTy =
+          CallEvent::getDeclaredResultType(calleeCtx->getDecl());
         if (!ReturnedTy.isNull()) {
           if (const Expr *Ex = dyn_cast<Expr>(CE)) {
             V = adjustReturnValue(V, Ex->getType(), ReturnedTy,