[clang] [LifetimeSafety] Extend function handling invalidating calls (PR #195064)

[Utkarsh Saxena via cfe-commits]

================
@@ -768,20 +768,23 @@ void FactsGenerator::handleInvalidatingCall(const Expr *Call,
                                             const FunctionDecl *FD,
                                             ArrayRef<const Expr *> Args) {
   const auto *MD = dyn_cast<CXXMethodDecl>(FD);
-  if (!MD || !MD->isInstance())
+  const bool IsInvalidatingMethod = MD && isInvalidationMethod(*MD);
+  const bool IsDestruction = isDestructionFunc(*FD);
+  if (!IsInvalidatingMethod && !IsDestruction)
     return;
 
-  if (!isInvalidationMethod(*MD))
-    return;
-  // Heuristics to turn-down false positives.
-  auto *DRE = dyn_cast<DeclRefExpr>(Args[0]);
+  // `destroy_at` get an implicit cast for the object argument, methods already
+  // give us the right shape.
+  const Expr *Target = IsDestruction ? Args[0]->IgnoreImpCasts() : Args[0];
+
+  // Heuristics to turn down false positives.
+  const auto *DRE = dyn_cast<DeclRefExpr>(Target);
   if (!DRE || DRE->getDecl()->getType()->isReferenceType())
     return;
 
-  OriginList *ThisList = getOriginsList(*Args[0]);
-  if (ThisList)
+  if (OriginList *ArgList = getOriginsList(*Args[0]))
     CurrentBlockFacts.push_back(FactMgr.createFact<InvalidateOriginFact>(
-        ThisList->getOuterOriginID(), Call));
+        ArgList->getOuterOriginID(), Call));
----------------
usx95 wrote:

> I ignore implicit casts here for pretty much the same reason as in the previous PR - to get the actual `DeclRefExpr` instead of the `LValueToRValue` cast.

> > It may make the false-negative with reference work

Yeah. My point is that you do not have to get a `DeclRefExpr`. Special casing only for it misses out on other LValue'd expressions.

Example:

```cpp
std::string* str1 = new std::string(1);
std::string* str2 = new std::string(2);
const char *p = str1->data();
std::destroy_at(flag ? str1 : str2);
(void)*p;

```



https://github.com/llvm/llvm-project/pull/195064