From: Pedro Alves <palves@redhat.com>
To: Simon Marchi <simon.marchi@polymtl.ca>,
"Jose E. Marchesi" <jose.marchesi@oracle.com>
Cc: Yao Qi <qiyaoltc@gmail.com>, "gdb@sourceware.org" <gdb@sourceware.org>
Subject: Re: C++ conversion status update
Date: Wed, 16 Dec 2015 00:21:00 -0000 [thread overview]
Message-ID: <5670AE9F.3060308@redhat.com> (raw)
In-Reply-To: <5670AE0A.20201@redhat.com>
Forgot to mention that this compiles down to the same as offsetof at -O2.
On 12/16/2015 12:19 AM, Pedro Alves wrote:
> diff --git a/gdb/common/vec.h b/gdb/common/vec.h
> index 6189283..a188b02 100644
> --- a/gdb/common/vec.h
> +++ b/gdb/common/vec.h
> @@ -437,13 +437,23 @@ DEF_VEC_FUNC_O(T) \
> DEF_VEC_ALLOC_FUNC_O(T) \
> struct vec_swallow_trailing_semi
>
> +/* Avoid offsetof (or its usual C implementation) as it triggers
> + -Winvalid-offsetof warnings with enum_flags types with G++ <= 4.4,
> + even though those types are memcpyable. This requires allocating a
> + dummy local VEC in all routines that use this, but that has the
> + advantage that it only works if T is default constructible, which
> + is exactly a check we want, to keep C compatibility. */
> +#define vec_offset(T, VPTR) ((size_t) ((char *) &(VPTR)->vec - (char *) VPTR))
Thanks,
Pedro Alves
next prev parent reply other threads:[~2015-12-16 0:21 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-24 13:07 Pedro Alves
2015-12-14 14:40 ` Yao Qi
2015-12-14 19:09 ` Pedro Alves
2015-12-15 11:39 ` Jose E. Marchesi
2015-12-15 20:03 ` Simon Marchi
2015-12-16 0:19 ` Pedro Alves
2015-12-16 0:21 ` Pedro Alves [this message]
2015-12-16 1:19 ` Simon Marchi
2015-12-16 20:11 ` Pedro Alves
2015-12-16 20:15 ` Pedro Alves
2015-12-16 20:30 ` Simon Marchi
2015-12-16 22:10 ` Pedro Alves
2015-12-16 22:59 ` Pedro Alves
2016-01-19 19:00 ` John Baldwin
2016-01-20 11:10 ` Pedro Alves
2016-01-20 23:33 ` John Baldwin
2016-01-21 11:38 ` Pedro Alves
2016-04-16 0:21 ` Pedro Alves
2016-04-18 16:51 ` Pedro Alves
2016-04-19 19:26 ` John Baldwin
2016-04-19 20:36 ` Pedro Alves
2016-04-19 21:40 ` John Baldwin
2016-04-19 22:20 ` Pedro Alves
2016-04-13 0:25 ` Pedro Alves
2016-04-13 11:07 ` Yao Qi
2016-04-13 14:13 ` Pedro Alves
2016-04-13 14:31 ` Sergio Durigan Junior
2016-04-13 12:41 ` Joel Brobecker
2016-04-13 14:04 ` Pedro Alves
2016-04-13 14:16 ` Joel Brobecker
2016-04-13 14:27 ` Luis Machado
2016-04-13 14:35 ` Marc Khouzam
2016-04-13 14:59 ` Joel Brobecker
2016-04-13 14:40 ` Pedro Alves
2016-04-18 17:29 ` Pedro Alves
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