Re: [PATCH] C: fix logic within c_expr::get_location

[Marek Polacek <polacek@redhat.com>]

On Wed, Aug 23, 2017 at 02:08:47PM -0400, David Malcolm wrote:
> In r251239 I added a c_expr::get_location method for use by
> c_parser_expr_list for building the vec<location_t> for
> an expression list, rather than using the location of the first token.
> 
> When determining whether to use the location within the tree node,
> or fall back to the range in the c_expr, I used EXPR_CAN_HAVE_LOCATION,
> rather than EXPR_HAS_LOCATION.  This meant that any tree nodes of kinds
> that *can* have a location but which erroneously had
>    EXPR_LOCATION (value) == UNKNOWN_LOCATION
> had that value added to the vec<location_t>, leading to missing
> location information when reporting on the issue
> (seen with gcc.dg/Wtraditional-conversion-2.c for m68k).
> 
> This patch addresses this in two ways:
> 
> (a) it fixes the specific issue in this failing test case, by
>     setting up the location properly on the EXCESS_PRECISION_EXPR.
> 
> (b) updating c_expr::get_location by only using the EXPR_LOCATION
>     if it's sane.  It could be argued that this could be papering over
>     other "missing location" bugs, but if there are any, they are
>     pre-existing ones exposed by r251239, and I'd rather have this fix
>     in place than play whack-a-mole on any other such bugs that may
>     be lurking in the codebase.
> 
> Successfully bootstrapped&regrtested on x86_64-pc-linux-gnu;
> I've verified the fix with --target=m68k-elf.
> 
> OK for trunk?

Ok, thanks.

	Marek