[clang] [LifetimeSafety] Implement multi-level origins (PR #168344)

[Utkarsh Saxena via cfe-commits]

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@@ -237,13 +348,25 @@ void FactsGenerator::handleGSLPointerConstruction(const CXXConstructExpr *CCE) {
   assert(isGslPointerType(CCE->getType()));
   if (CCE->getNumArgs() != 1)
     return;
-  if (hasOrigin(CCE->getArg(0)))
-    killAndFlowOrigin(*CCE, *CCE->getArg(0));
-  else
+
+  const Expr *Arg = CCE->getArg(0);
+  if (isGslPointerType(Arg->getType())) {
+    OriginList *ArgList = getOriginsList(*Arg);
+    assert(ArgList && "GSL pointer argument should have an origin list");
+    // GSL pointer is constructed from another gsl pointer.
+    // Example:
+    //  View(View v);
+    //  View(const View &v);
+    if (Arg->isGLValue())
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usx95 wrote:

Hmm. This indeed looks like a pattern of forcing an `LValueToRValue` conversion.

https://github.com/llvm/llvm-project/pull/168344