[BUG] missing warning for pointer arithmetic out of bounds

[Alejandro Colomar]

Hi!

For the following program:


     $ cat buf.c
     #include <stdio.h>

     int main(void)
     {
         char *p, buf[5];

         p = buf + 6;
         printf("%p\n", p);
     }


There are no warnings in gcc, as I would expect:

     $ gcc -Wall -Wextra buf.c -O0

Clang does warn, however:

     $ clang -Weverything -Wall -Wextra buf.c -O0
     buf.c:8:17: warning: format specifies type 'void *' but the argument has 
type 'char *' [-Wformat-pedantic]
         printf("%p\n", p);
                 ~~     ^
                 %s
     buf.c:7:6: warning: the pointer incremented by 6 refers past the end of the 
array (that contains 5 elements) [-Warray-bounds-pointer-arithmetic]
         p = buf + 6;
             ^     ~
     buf.c:5:2: note: array 'buf' declared here
         char *p, buf[5];
         ^
     2 warnings generated.

Cheers,

Alex


-- 
<http://www.alejandro-colomar.es/>
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