[clang] [clang][bytecode] Fix __builtin_is_within_lifetime in initializers (PR #147480)

[Timm Baeder via cfe-commits]

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@@ -2208,15 +2208,27 @@ static bool interp__builtin_is_within_lifetime(InterpState &S, CodePtr OpPC,
   if (Ptr.isOnePastEnd())
     return Error(1);
 
-  bool Result = true;
+  bool Result = Ptr.getLifetime() != Lifetime::Ended;
   if (!Ptr.isActive()) {
     Result = false;
   } else {
     if (!CheckLive(S, OpPC, Ptr, AK_Read))
       return false;
     if (!CheckMutable(S, OpPC, Ptr))
       return false;
+    if (!CheckDummy(S, OpPC, Ptr, AK_Read))
+      return false;
+  }
+
+  // Check if we're currently running an initializer.
+  for (InterpFrame *Frame = S.Current; Frame; Frame = Frame->Caller) {
+    if (const Function *F = Frame->getFunction();
+        F && F->isConstructor() && Frame->getThis().block() == Ptr.block()) {
+      return Error(2);
+    }
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tbaederr wrote:

Forgot to push that, thanks!

https://github.com/llvm/llvm-project/pull/147480