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From: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Sparse Mailing-list <linux-sparse@vger.kernel.org>
Subject: Re: [PATCH 15/17] scope: give a scope for labels & gotos
Date: Mon, 13 Apr 2020 22:00:43 +0200	[thread overview]
Message-ID: <20200413200043.6mv4d67pioex52wb@ltop.local> (raw)
In-Reply-To: <CAHk-=wjMSeVVQHZ23=HJ3V-yYPooeuHNHmZtexUVRKg_e5VMXA@mail.gmail.com>

On Mon, Apr 13, 2020 at 12:32:41PM -0700, Linus Torvalds wrote:
> 
> I _feel_ like the fix to that should be that the only thing that
> creates the actual symbol is the label definition, and that the goto
> should only ever use the 'ident' and we'd tie the two together later.

Yes, I tried that too but it didn't worked because:
 
> But yeah, that "tie the two together later" may not work, simply
> because scoping is so tightly tied to parsing in sparse.
> 
> So maybe your approach is the best one.
> 
> It feels hacky and wrong, but maybe that just fundamentally comes from
> labels having that very special "use = implicit declaration" thing.

Yes, that and the way the symbol 'table' is done: very clever but
unusable for our problem here. But maybe there is something that can
be done there. Currently end_scope() sets scope->symbols to NULL but
as far as I can see, this is not really needed and, if left, the
"tie the two together later" could be done by doing a symbol lookup
via this list instead of the usual lookup via ident->symbols, much
like classical symbol tables are used. It should be quite easy.
I'll give it a try because I'm also not really satisfied with my
current solution giving a kind of secondary scope to the statements.

-- Luc

  reply	other threads:[~2020-04-13 20:00 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-13 16:15 [PATCH 00/17] detect invalid branches at evaluation time Luc Van Oostenryck
2020-04-13 16:15 ` [PATCH 01/17] bad-goto: add testcase for 'jump inside discarded expression statement' Luc Van Oostenryck
2020-04-13 16:15 ` [PATCH 02/17] bad-goto: add testcases for linearization of invalid labels Luc Van Oostenryck
2020-04-13 16:15 ` [PATCH 03/17] bad-goto: add more testcases Luc Van Oostenryck
2020-04-13 16:15 ` [PATCH 04/17] bad-goto: do not linearize if the IR will be invalid Luc Van Oostenryck
2020-04-13 16:15 ` [PATCH 05/17] bad-goto: reorg test in evaluate_goto_statement() Luc Van Oostenryck
2020-04-13 16:15 ` [PATCH 06/17] bad-goto: simplify testing of undeclared labels Luc Van Oostenryck
2020-04-13 16:15 ` [PATCH 07/17] bad-goto: do not linearize function with " Luc Van Oostenryck
2020-04-13 16:15 ` [PATCH 08/17] bad-goto: catch labels with reserved names Luc Van Oostenryck
2020-04-13 16:15 ` [PATCH 09/17] scope: no memset() needed after __alloc_scope() Luc Van Oostenryck
2020-04-13 16:15 ` [PATCH 10/17] scope: move scope opening/ending inside compound_statement() Luc Van Oostenryck
2020-04-13 16:15 ` [PATCH 11/17] scope: make function scope the same as the body block scope Luc Van Oostenryck
2020-04-13 16:16 ` [PATCH 12/17] scope: s/{start,end}_symbol_scope/{start,end}_block_scope/ Luc Van Oostenryck
2020-04-13 16:16 ` [PATCH 13/17] scope: let labels have their own scope Luc Van Oostenryck
2020-04-13 17:30   ` Linus Torvalds
2020-04-13 16:16 ` [PATCH 14/17] scope: add is_in_scope() Luc Van Oostenryck
2020-04-13 16:16 ` [PATCH 15/17] scope: give a scope for labels & gotos Luc Van Oostenryck
2020-04-13 17:52   ` Linus Torvalds
2020-04-13 18:54     ` Luc Van Oostenryck
2020-04-13 19:32       ` Linus Torvalds
2020-04-13 20:00         ` Luc Van Oostenryck [this message]
2020-04-13 22:40         ` Linus Torvalds
2020-04-13 23:39           ` Luc Van Oostenryck
2020-04-14  7:49             ` Luc Van Oostenryck
2020-04-14 18:19               ` Linus Torvalds
2020-04-14 23:09                 ` Luc Van Oostenryck
2020-04-15  0:59                   ` Linus Torvalds
2020-05-14 22:22                     ` Luc Van Oostenryck
2020-04-13 16:16 ` [PATCH 16/17] bad-goto: catch gotos inside expression statements Luc Van Oostenryck
2020-04-13 16:16 ` [PATCH 17/17] bad-goto: cleanup evaluate_goto() Luc Van Oostenryck

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