From: Simon Marchi <simark@simark.ca>
To: Mark Wielaard <mark@klomp.org>,
gdb-patches@sourceware.org, John Baldwin <jhb@FreeBSD.org>
Cc: Sam James <sam@gentoo.org>, Tom Tromey <tom@tromey.com>
Subject: Re: [PATCHv3] gdb: Replace memcpy with std::copy to avoid some g++ warnings on sparc
Date: Tue, 24 Jan 2023 16:29:20 -0500 [thread overview]
Message-ID: <2f5e28eb-a5f2-0995-506f-b6632333c7b2@simark.ca> (raw)
In-Reply-To: <20230124201624.875658-1-mark@klomp.org>
On 1/24/23 15:16, Mark Wielaard wrote:
> For some reason g++ 12.2.1 on sparc produces a spurious warnings for
> stringop-overread and restrict in fbsd-tdep.c for some memcpy calls.
> Use std::copy to avoid those.
>
> In function ‘void* memcpy(void*, const void*, size_t)’,
> inlined from ‘gdb::optional<std::vector<unsigned char, gdb::default_init_allocator<unsigned char, std::allocator<unsigned char> > > > fbsd_make_note_desc(target_object, uint32_t)’ at ../../binutils-gdb/gdb/fbsd-tdep.c:666:10:
> /usr/include/bits/string_fortified.h:29:33: error: ‘void* __builtin_memcpy(void*, const void*, long unsigned int)’ specified bound 18446744073709551612 exceeds maximum object size 9223372036854775807 [-Werror=stringop-overflow=]
>
> In function ‘void* memcpy(void*, const void*, size_t)’,
> inlined from ‘gdb::optional<std::vector<unsigned char, gdb::default_init_allocator<unsigned char, std::allocator<unsigned char> > > > fbsd_make_note_desc(target_object, uint32_t)’ at ../../binutils-gdb/gdb/fbsd-tdep.c:673:10:
> /usr/include/bits/string_fortified.h:29:33: error: ‘void* __builtin_memcpy(void*, const void*, long unsigned int)’ accessing 18446744073709551612 bytes at offsets 0 and 0 overlaps 9223372036854775801 bytes at offset -9223372036854775805 [-Werror=restrict]
>
> gdb/ChangeLog:
>
> * fbsd-tdep.c (fbsd_make_note_desc): Use std::copy instead
> of memcpy.
> ---
>
> V3: Drop diagnostic suppressions just use std::copy
> V2: Fix typos and add example errors to commit messages
>
> gdb/fbsd-tdep.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/gdb/fbsd-tdep.c b/gdb/fbsd-tdep.c
> index 203390d9880..ebc15543149 100644
> --- a/gdb/fbsd-tdep.c
> +++ b/gdb/fbsd-tdep.c
> @@ -662,8 +662,9 @@ fbsd_make_note_desc (enum target_object object, uint32_t structsize)
> return buf;
>
> gdb::byte_vector desc (sizeof (structsize) + buf->size ());
> - memcpy (desc.data (), &structsize, sizeof (structsize));
> - memcpy (desc.data () + sizeof (structsize), buf->data (), buf->size ());
> + std::copy (&structsize, &structsize + sizeof (structsize), desc.data ());
> + std::copy (buf->data (), desc.data () + sizeof (structsize),
> + desc.data () + sizeof (structsize));
I think the second argument to the second std::copy call should have
`buf->data ()`, not `desc.data (). Otherwise, LGTM. However, it would
be nice to have the approval from John Baldwin.
Simon
next prev parent reply other threads:[~2023-01-24 21:29 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-24 20:16 Mark Wielaard
2023-01-24 21:29 ` Simon Marchi [this message]
2023-01-24 21:49 ` Mark Wielaard
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