Re: scratch/igc warning

[Pip Cet]

On Wednesday, June 26th, 2024 at 14:08, Andrea Corallo <acorallo@gnu.org> wrote:

> GCC 12.3 is giving me this warning building scratch/igc:
> 
> ========
> CC xfaces.o
> In file included from /usr/include/string.h:535,
> from ../lib/string.h:41,
> from lisp.h:29,
> from xfaces.c:226:
> In function ‘memset’,
> inlined from ‘make_realized_face’ at xfaces.c:4581:3,
> inlined from ‘realize_gui_face’ at xfaces.c:6214:10,
> inlined from ‘realize_face’ at xfaces.c:6124:12:
> /usr/include/x86_64-linux-gnu/bits/string_fortified.h:59:10: warning: 
> ‘__builtin_memset’ offset [164, 303] from the object at ‘face’ is out of the 
> bounds of referenced subobject ‘id’ with type ‘int’ at offset 160 
> [-Warray-bounds]
> 59 | return __builtin___memset_chk (__dest, __ch, __len,
> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 60 | __glibc_objsize0 (__dest));
> | ~~~~~~~~~~~~~~~~~~~~~~~~~~
> In file included from termhooks.h:27,
> from frame.h:22,
> from xfaces.c:229:
> dispextern.h: In function ‘realize_face’:
> dispextern.h:1730:7: note: subobject ‘id’ declared here
> 1730 | int id;
> | ^~
> In function ‘memset’,
> inlined from ‘make_realized_face’ at xfaces.c:4581:3,
> inlined from ‘realize_tty_face’ at xfaces.c:6641:10,
> inlined from ‘realize_face’ at xfaces.c:6126:12:
> /usr/include/x86_64-linux-gnu/bits/string_fortified.h:59:10: warning: 
> ‘__builtin_memset’ offset [164, 303] from the object at ‘face’ is out of the 
> bounds of referenced subobject ‘id’ with type ‘int’ at offset 160 
> [-Warray-bounds]
> 59 | return __builtin___memset_chk (__dest, __ch, __len,
> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 60 | __glibc_objsize0 (__dest));
> | ~~~~~~~~~~~~~~~~~~~~~~~~~~
> dispextern.h: In function ‘realize_face’:
> dispextern.h:1730:7: note: subobject ‘id’ declared here
> 1730 | int id;
> | ^~
> In function ‘memset’,
> inlined from ‘make_realized_face’ at xfaces.c:4581:3,
> inlined from ‘realize_face’ at xfaces.c:6130:14:
> /usr/include/x86_64-linux-gnu/bits/string_fortified.h:59:10: warning: 
> ‘__builtin_memset’ offset [164, 303] from the object at ‘face’ is out of the 
> bounds of referenced subobject ‘id’ with type ‘int’ at offset 160 
> [-Warray-bounds]
> 59 | return __builtin___memset_chk (__dest, __ch, __len,
> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 60 | __glibc_objsize0 (__dest));
> | ~~~~~~~~~~~~~~~~~~~~~~~~~~
> dispextern.h: In function ‘realize_face’:
> dispextern.h:1730:7: note: subobject ‘id’ declared here
> 1730 | int id;
> | ^~
> ========
> 
> ATM don't know if it's a real issue or a false positive so I thought was
> worth mentioning.

Something in between: the code is trying to clear a struct partially by 
memsetting starting from a given offset to the end of the struct. However, it's 
not specific to the igc branch.

Pip