[C/C++ PATCH] Reject declarators with huge arrays (PR c/68107, c++/68266)

[Joseph Myers]

On Tue, 10 Nov 2015, Marek Polacek wrote:

> While both C and C++ FEs are able to reject e.g.
> int a[__SIZE_MAX__ / sizeof(int)];
> they are accepting code such as
> int (*a)[__SIZE_MAX__ / sizeof(int)];
> 
> As Joseph pointed out, any construction of a non-VLA type whose size is half or
> more of the address space should receive a compile-time error.
> 
> Done by moving up the check for the size in bytes so that it checks check every
> non-VLA complete array type constructed in the course of processing the
> declarator.  Since the C++ FE had the same problem, I've fixed it up there as
> well.  And that's why I had to twek dg-error of two C++ tests; if the size of
> an array is considered invalid, we give an error message with word "unnamed".
> 
> (I've removed the comment about crashing in tree_to_[su]hwi since that seems
> to no longer be the case.)
> 
> Bootstrapped/regtested on x86_64-linux, ok for trunk?

The C front-end changes are OK.

-- 
Joseph S. Myers
joseph@codesourcery.com