From: Eric Wong <e@80x24.org>
To: Junio C Hamano <gitster@pobox.com>
Cc: Derrick Stolee <stolee@gmail.com>,
Johannes Schindelin <Johannes.Schindelin@gmx.de>,
Phillip Wood <phillip.wood@dunelm.org.uk>,
git@vger.kernel.org
Subject: Re: [PATCH v2 18/19] OFFSETOF_VAR macro to simplify hashmap iterators
Date: Fri, 4 Oct 2019 17:26:03 +0000 [thread overview]
Message-ID: <20191004172603.GA7215@dcvr> (raw)
In-Reply-To: <xmqqk19l89xt.fsf@gitster-ct.c.googlers.com>
Junio C Hamano <gitster@pobox.com> wrote:
> Eric Wong <e@80x24.org> writes:
>
> > That seems too tedious. I'm learning towards just initializing
> > var = NULL in the start of the for-loop:
> >
> > @@ -449,7 +449,8 @@ static inline struct hashmap_entry *hashmap_iter_first(struct hashmap *map,
> > * containing a @member which is a "struct hashmap_entry"
> > */
> > #define hashmap_for_each_entry(map, iter, var, member) \
> > - for (var = hashmap_iter_first_entry_offset(map, iter, \
> > + for (var = NULL /* squelch uninitialized warnings for OFFSETOF_VAR */, \
> > + var = hashmap_iter_first_entry_offset(map, iter, \
> > OFFSETOF_VAR(var, member)); \
>
> That looks a bit too ugly for my taste. I've added an updated
> version (see below) and then rebased the whole thing on top of it.
I prefer to minimize the amount of stuff we do to work around
buggy compilers (in case they get fixed and old versions are
obsoleted).
If it's just clang with this problem, we know clang sets
__GNUC__, so we can use __typeof__ directly (bypassing extra
parentheses in our TYPEOF macro) to get around the warning:
#if defined(__GNUC__) /* clang sets this, too */
#define OFFSETOF_VAR(ptr, member) offsetof(__typeof__(*ptr), member)
#else /* !__GNUC__ */
...
That said, there could be other compilers which don't set
__GNUC__ and have the same problem as clang. But maybe those
compilers are too buggy and we already ignore invalid warnings
on those compilers.
next prev parent reply other threads:[~2019-10-04 17:26 UTC|newest]
Thread overview: 71+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-26 2:43 [PATCH 00/11] hashmap: bugfixes, safety fixes, and WIP improvements Eric Wong
2019-08-26 2:43 ` [PATCH 01/11] diff: use hashmap_entry_init on moved_entry.ent Eric Wong
2019-08-27 13:31 ` Derrick Stolee
2019-08-26 2:43 ` [PATCH 02/11] packfile: use hashmap_entry in delta_base_cache_entry Eric Wong
2019-08-26 2:43 ` [PATCH 03/11] hashmap_entry_init takes "struct hashmap_entry *" Eric Wong
2019-08-27 13:35 ` Derrick Stolee
2019-08-28 15:01 ` Johannes Schindelin
2019-08-30 19:48 ` Eric Wong
2019-09-02 13:46 ` Johannes Schindelin
2019-08-26 2:43 ` [PATCH 04/11] hashmap_entry: detect improper initialization Eric Wong
2019-08-27 9:10 ` Johannes Schindelin
2019-08-27 9:49 ` Eric Wong
2019-08-27 22:16 ` Junio C Hamano
2019-08-28 15:04 ` Johannes Schindelin
2019-08-28 9:03 ` Phillip Wood
2019-08-30 19:52 ` Eric Wong
2019-09-08 7:49 ` [RFC 04/11] coccicheck: detect hashmap_entry.hash assignment Eric Wong
2019-09-09 18:15 ` Junio C Hamano
2019-08-26 2:43 ` [PATCH 05/11] hashmap_get_next takes "const struct hashmap_entry *" Eric Wong
2019-08-26 2:43 ` [PATCH 06/11] hashmap_add takes "struct " Eric Wong
2019-08-26 2:43 ` [PATCH 07/11] hashmap_get takes "const struct " Eric Wong
2019-08-26 2:43 ` [PATCH 08/11] hashmap_remove " Eric Wong
2019-08-26 2:43 ` [PATCH 09/11] hashmap_put takes "struct " Eric Wong
2019-08-26 2:43 ` [PATCH 10/11] introduce container_of macro Eric Wong
2019-08-27 14:49 ` Derrick Stolee
2019-08-28 9:11 ` Phillip Wood
2019-08-30 19:43 ` Eric Wong
2019-08-26 2:43 ` [PATCH 11/11] hashmap_get_next returns "struct hashmap_entry *" Eric Wong
2019-08-27 14:53 ` Derrick Stolee
2019-08-30 19:36 ` Eric Wong
2019-09-24 1:03 ` [PATCH v2 00/19] hashmap bug/safety/ease-of-use fixes Eric Wong
2019-09-24 1:03 ` [PATCH v2 01/19] diff: use hashmap_entry_init on moved_entry.ent Eric Wong
2019-09-24 1:03 ` [PATCH v2 02/19] coccicheck: detect hashmap_entry.hash assignment Eric Wong
2019-09-25 12:44 ` Derrick Stolee
2019-09-24 1:03 ` [PATCH v2 03/19] packfile: use hashmap_entry in delta_base_cache_entry Eric Wong
2019-09-24 1:03 ` [PATCH v2 04/19] hashmap_entry_init takes "struct hashmap_entry *" Eric Wong
2019-09-25 12:48 ` Derrick Stolee
2019-09-24 1:03 ` [PATCH v2 05/19] hashmap_get_next takes "const struct " Eric Wong
2019-09-24 1:03 ` [PATCH v2 06/19] hashmap_add takes "struct " Eric Wong
2019-09-24 1:03 ` [PATCH v2 07/19] hashmap_get takes "const struct " Eric Wong
2019-09-25 12:52 ` Derrick Stolee
2019-09-30 9:57 ` Eric Wong
2019-09-24 1:03 ` [PATCH v2 08/19] hashmap_remove " Eric Wong
2019-09-25 12:54 ` Derrick Stolee
2019-09-24 1:03 ` [PATCH v2 09/19] hashmap_put takes "struct " Eric Wong
2019-09-24 1:03 ` [PATCH v2 10/19] introduce container_of macro Eric Wong
2019-09-25 13:12 ` Derrick Stolee
2019-09-30 10:39 ` Eric Wong
2019-09-24 1:03 ` [PATCH v2 11/19] hashmap_get_next returns "struct hashmap_entry *" Eric Wong
2019-09-25 13:05 ` Derrick Stolee
2019-09-24 1:03 ` [PATCH v2 12/19] hashmap: use *_entry APIs to wrap container_of Eric Wong
2019-09-25 13:15 ` Derrick Stolee
2019-09-24 1:03 ` [PATCH v2 13/19] hashmap_get{,_from_hash} return "struct hashmap_entry *" Eric Wong
2019-09-24 1:03 ` [PATCH v2 14/19] hashmap_cmp_fn takes hashmap_entry params Eric Wong
2019-09-24 1:03 ` [PATCH v2 15/19] hashmap: use *_entry APIs for iteration Eric Wong
2019-09-24 1:03 ` [PATCH v2 16/19] hashmap: hashmap_{put,remove} return hashmap_entry * Eric Wong
2019-09-24 1:03 ` [PATCH v2 17/19] hashmap: introduce hashmap_free_entries Eric Wong
2019-09-24 1:03 ` [PATCH v2 18/19] OFFSETOF_VAR macro to simplify hashmap iterators Eric Wong
2019-09-30 16:58 ` Junio C Hamano
2019-10-04 1:18 ` Junio C Hamano
2019-10-04 2:51 ` Eric Wong
2019-10-04 3:29 ` Junio C Hamano
2019-10-04 17:26 ` Eric Wong [this message]
2019-10-06 0:04 ` Junio C Hamano
2019-09-24 1:03 ` [PATCH v2 19/19] hashmap: remove type arg from hashmap_{get,put,remove}_entry Eric Wong
2019-09-25 12:42 ` Derrick Stolee
2019-09-25 13:30 ` [PATCH v2 00/19] hashmap bug/safety/ease-of-use fixes Derrick Stolee
2019-09-26 8:39 ` Johannes Schindelin
2019-09-30 10:01 ` Eric Wong
2019-09-26 13:48 ` Phillip Wood
2019-09-29 9:22 ` Junio C Hamano
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