[cfe-commits] [PATCH] Catching large array sizes

[Abramo Bagnara]

Il 22/07/2012 20:50, Aaron Ballman ha scritto:
> This patch is to address PR13271 -- the problem comes from declaring
> an array that's "too large" within a structure, and then attempting to
> take the sizeof that structure.  We have an assert in
> ASTContext::getTypeInfoImpl about the size of constant arrays, but the
> problem is that this is called when attempting to get the sizeof a
> structure.  We've already reported the issue to the user about the
> array being too large by this point, and so the assert triggers.
> 
> I'm not convinced the assert is required here, so I've removed it in
> this patch.  However, I'm also not convinced the assert is invalid and
> am open to suggestions as to other ways to handle the error.

The assertion is needed because unfortunately type size are currently
evaluated in bits (and not in bytes) inside an uint64_t.

This means that perfectly valid sizeof >= 1 << 61 are not evaluatable
and clang silently produced invalid code. The assertion was introduced
to avoid that.

The proper fix should be to make clang able to evaluate correctly type
size in bytes also when it is >= 1 << 61.