* [PATCHv3] gdb: Replace memcpy with std::copy to avoid some g++ warnings on sparc
@ 2023-01-24 20:16 Mark Wielaard
2023-01-24 21:29 ` Simon Marchi
0 siblings, 1 reply; 3+ messages in thread
From: Mark Wielaard @ 2023-01-24 20:16 UTC (permalink / raw)
To: gdb-patches; +Cc: Simon Marchi, Sam James, Tom Tromey, Mark Wielaard
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));
return desc;
}
--
2.31.1
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCHv3] gdb: Replace memcpy with std::copy to avoid some g++ warnings on sparc
2023-01-24 20:16 [PATCHv3] gdb: Replace memcpy with std::copy to avoid some g++ warnings on sparc Mark Wielaard
@ 2023-01-24 21:29 ` Simon Marchi
2023-01-24 21:49 ` Mark Wielaard
0 siblings, 1 reply; 3+ messages in thread
From: Simon Marchi @ 2023-01-24 21:29 UTC (permalink / raw)
To: Mark Wielaard, gdb-patches, John Baldwin; +Cc: Sam James, Tom Tromey
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
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCHv3] gdb: Replace memcpy with std::copy to avoid some g++ warnings on sparc
2023-01-24 21:29 ` Simon Marchi
@ 2023-01-24 21:49 ` Mark Wielaard
0 siblings, 0 replies; 3+ messages in thread
From: Mark Wielaard @ 2023-01-24 21:49 UTC (permalink / raw)
To: Simon Marchi; +Cc: gdb-patches, John Baldwin, Sam James, Tom Tromey
Hi Simon,
On Tue, Jan 24, 2023 at 04:29:20PM -0500, Simon Marchi wrote:
> > 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.
Bah, what a stupid typo. You are right of course. Sorry. v4 coming up.
Thanks,
Mark
^ permalink raw reply [flat|nested] 3+ messages in thread
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2023-01-24 20:16 [PATCHv3] gdb: Replace memcpy with std::copy to avoid some g++ warnings on sparc Mark Wielaard
2023-01-24 21:29 ` Simon Marchi
2023-01-24 21:49 ` Mark Wielaard
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