[Bug c/108896] provide "element_count" attribute to give more context to __builtin_dynamic_object_size() and -fsanitize=bounds

[qinzhao at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108896

--- Comment #41 from qinzhao at gcc dot gnu.org ---
my private gcc is able to use the element_count information in bound sanitizer
now:
[opc@qinzhao-ol8u3-x86 108896]$ cat t6.c
#include <stdlib.h>
#include <assert.h>
struct P {
  int k;
  int x[] __attribute__ ((element_count ("k")));
} *p;

void __attribute__ ((noinline)) store(int a, int b) 
{
  p = (struct P *)malloc (sizeof (struct P) + a * sizeof (int));
  p->k = a;
  return;
}

int main()
{
 store(7, 7);
 p->x[7] = 1;
}
[opc@qinzhao-ol8u3-x86 108896]$ sh t
/home/opc/Install/latest-d/bin/gcc -O -fsanitize=bounds-strict t6.c
t6.c:18:6: runtime error: index 7 out of bounds for type 'int [*]'
[opc@qinzhao-ol8u3-x86 108896]$