[Tinycc-devel] segfault with static array initialized by a macro

[Didier Barvaux]

Hello all,

In encountered what seems to be a bug in TCC (git revision
ad5f3758c38f2364f03205dcb9fd48142d2d4499). I narrowed it down to the
following test case.


$ cat segfault_with_static_array.c

#include <stdio.h>

#define LENGTH1  10
#define LENGTH2  20

#define max(a, b)  (((a) > (b)) ? (a) : (b))

int main(int argc, char *argv[])
{
        static unsigned char data[max(LENGTH1, LENGTH2)];

        printf("max(%d, %d) = %d\n", LENGTH1, LENGTH2, max(LENGTH1,
        LENGTH2)); printf("data = %p\n", data);
        data[0] = 0x42;

        return 0;
}


$ tcc -o segfault_with_static_array -Wall -Werror \
  segfault_with_static_array.c
$ ./segfault_with_static_array
max(10, 20) = 20
data = (nil)
Erreur de segmentation
$ echo $?
139


The program above works with GCC 4.5, GCC 4.6, GCC 4.7 and Clang 3.1.
It does not fail with TCC if I do not use the max() macro or remove the
'static' keyword for the 'data' array.

Regards,
Didier

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