[Bug c/83859] New: Please add new attribute which will establish relation between parameters for buffer and its size

[bugzilla@poradnik-webmastera.com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83859

            Bug ID: 83859
           Summary: Please add new attribute which will establish relation
                    between parameters for buffer and its size
           Product: gcc
           Version: 8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: bugzilla@poradnik-webmastera.com
  Target Milestone: ---

gcc can detect if buffer size passed to function like strncpy is incorrect,
e.g. it is sizeof pointer. It would be good to have similar diagnostics enabled
for custom functions also accepts buffer and its size. Please add new function
attribute which would allow to do this and appropriate diagnostics which will
use it. I propose to add following attribute with two parameters - indices of
buffer and its size arguments. Note that function may accept multiple such
pairs, so it should be possible to use this attribute multiple times.

__attribute__((buffer_size(1, 2)))
void foo(char* dst, size_t dstsize);