[PATCH] D40698: [ubsan] Diagnose noreturn functions which return

[Vedant Kumar via Phabricator via cfe-commits]

vsk added inline comments.


================
Comment at: lib/CodeGen/CGCall.cpp:2756
                                          SourceLocation EndLoc) {
+  if (FI.isNoReturn()) {
+    // Noreturn functions don't return.
----------------
efriedma wrote:
> Unfortunately, this won't catch cases where the caller has a noreturn marking, but the callee doesn't.  Maybe strip the noreturn attribute from the caller, then put the sanitizer check into both the caller and callee?
If the caller sees a noreturn marking on the call target, inserting a 'reached-unreachable' check after the call is UB, and the optimizer throws it away. Perhaps you had a different case in mind?


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Comment at: lib/CodeGen/CGCall.cpp:2764
     // Naked functions don't have epilogues.
-    Builder.CreateUnreachable();
+    EmitUnreachable(EndLoc);
     return;
----------------
efriedma wrote:
> This is likely a problem.  Not because the code is supposed to be reachable, but because putting additional code into a naked function can have weird effects.  Probably not worth messing with this case.
Sorry for the noisy change. I recognized it as a mistake a second after I uploaded the new diff :(.


https://reviews.llvm.org/D40698