From: Jason Merrill <jason_merrill@redhat.com>
To: kenner@vlsi1.ultra.nyu.edu (Richard Kenner)
Cc: law@cygnus.com, gcc@gcc.gnu.org, jason_merrill@redhat.com
Subject: Re: Added error message (for too-large array)
Date: Tue, 25 Sep 2001 04:52:00 -0000 [thread overview]
Message-ID: <m3d74flc9m.fsf@prospero.cambridge.redhat.com> (raw)
In-Reply-To: <10109111102.AA21306@vlsi1.ultra.nyu.edu>
>>>>> "Richard" == Richard Kenner <kenner@vlsi1.ultra.nyu.edu> writes:
> What was the purpose of adding an error message in layout_type when an
> array's size cannot be represented in size_t?
If the size cannot be represented in size_t, it isn't represented
internally in gcc in any useful way; it overflows to some number bearing
little relation to what the user intended.
Now I notice that the C frontend already caught this, in grokdeclarator. I
suppose the C++ frontend could handle it similarly, but I didn't see how a
type too large to represent could be useful for any language.
> We should give an error if the size of an *object* can't be
> representable, but why a type?
I suppose that moving the test for overflowing TYPE_SIZE to layout_decl
would be plausible.
> Note that you don't check for RECORD_TYPE, just ARRAY_TYPE.
I suppose that would make sense for completeness, though the problem is
much less likely there.
> It's a fairly common idiom in Ada to make an array type whose bounds
> are all integers to represent "all memory". If it's an array of bytes
> that's OK, but not if it's an array of anything wider. So this error
> causes problems there.
It would think the Ada frontend should set TYPE_SIZE itself for such an
ARRAY_TYPE, rather than let the middle-end come up with a meaningless
value.
Jason
next prev parent reply other threads:[~2001-09-25 4:52 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-09-11 3:57 Added error message Richard Kenner
2001-09-25 4:52 ` Jason Merrill [this message]
2001-09-25 5:41 Added error message (for too-large array) Richard Kenner
2001-09-25 6:23 ` Jason Merrill
2001-09-25 6:30 dewar
2001-09-25 6:39 ` Jason Merrill
2001-09-25 7:05 Richard Kenner
2001-09-25 7:05 dewar
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