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gdb: Replace memcpy with std::copy to avoid some g++ warnings on sparc

Message ID 20230125212746.994955-1-mark@klomp.org
State Superseded
Headers
Series gdb: Replace memcpy with std::copy to avoid some g++ warnings on sparc |

Commit Message

Mark Wielaard Jan. 25, 2023, 9:27 p.m. UTC 
  For some reason g++ 12.2.1 on sparc produces spurious warnings for
stringop-overread and restrict in fbsd-tdep.c for a memcpy call.
Use std::copy to avoid the warnings:

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.
---

 V6: Only use std::copy for the second memcpy
 V5: Use buf->begin (), buf->end () in second std::copy
 V4: Fix std::copy argument typo
 V3: Drop diagnostic suppressions just use std::copy
 V2: Fix typos and add example errors to commit messages

 gdb/fbsd-tdep.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Tom Tromey Jan. 30, 2023, 6:52 p.m. UTC | #1 
>>>>> "Mark" == Mark Wielaard <mark@klomp.org> writes:

Mark> For some reason g++ 12.2.1 on sparc produces spurious warnings for
Mark> stringop-overread and restrict in fbsd-tdep.c for a memcpy call.
Mark> Use std::copy to avoid the warnings:

Thank you.  This is ok.

Tom
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Patch

diff --git a/gdb/fbsd-tdep.c b/gdb/fbsd-tdep.c
index 203390d9880..3a7cb9b14ea 100644
--- a/gdb/fbsd-tdep.c
+++ b/gdb/fbsd-tdep.c
@@ -663,7 +663,7 @@  fbsd_make_note_desc (enum target_object object, uint32_t structsize)
 
   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 (buf->begin (), buf->end (), desc.data () + sizeof (structsize));
   return desc;
 }