[PATCH] D115844: [ubsan] Using metadata instead of prologue data for function sanitizer

[Yuanfang Chen via Phabricator via cfe-commits]

ychen added a comment.

In D115844#3321190 <https://reviews.llvm.org/D115844#3321190>, @pcc wrote:

> On the bug you have:
>
>   define internal fastcc void @​_Z4callIiE4taskv.resume(%_Z4callIiE4taskv.Frame* noalias nonnull align 8 dereferenceable(24
>       ) %FramePtr) #​1 prologue <{ i32, i32 }> <{ i32 846595819, i32 trunc (i64 sub (i64 ptrtoint (i8** @​1 to i64), i64 ptrtoint (void ()* @​_Z4callIiE4taskv to i64)) to i32) }> {...}
>
> Is it possible for the C/C++ code to take the address of the function `_Z4callIiE4taskv.resume` and call it indirectly?

`*.resume` is a compiler inserted function that is opaque to the programmer. It is called indirectly most of the time if not all the time.

> If not, it seems like the right fix would be to arrange for the prologue data to be dropped on the `.resume` function instead of duplicating it there. I would also imagine that whatever signature you have on the `.resume` function would be incorrect since it appears that the coro splitting pass will use a different function signature for that function.

That is addressed by D116130 <https://reviews.llvm.org/D116130>. @rjmccall suggested the direction of this patch (which I agreed) https://reviews.llvm.org/D114728#3159303.

> Note that D119296 <https://reviews.llvm.org/D119296> will have the same problem.

Thanks for the info!


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