Subversion Repositories openrisc_2011-10-31

/* PR target/17377

   Bug in code emitted by "return" pattern on CRIS: missing pop of

   forced return address on stack.  */

int calls = 0;

void *f (int) __attribute__ ((__noinline__));

void *

f (int i)

{

  /* The code does a little brittle song and dance to trig the "return"

     pattern instead of the function epilogue.  This must still be a

     leaf function for the bug to be exposed.  */

  if (calls++ == 0)

    return __builtin_return_address (0);

  switch (i)

    {

    case 1:

      return f;

    case 0:

      return __builtin_return_address (0);

    }

  return 0;

}

int x;

void *y (int i) __attribute__ ((__noinline__,__noclone__));

void *

y (int i)

{

  x = 0;

  /* This must not be a sibling call: the return address must appear

     constant for different calls to this function.  Postincrementing x

     catches otherwise unidentified multiple returns (e.g. through the

     return-address register and then this epilogue popping the address

     stored on stack in "f").  */

  return (char *) f (i) + x++;

}

int

main (void)

{

  void *v = y (4);

  if (y (1) != f

      /* Can't reasonably check the validity of the return address

         above, but it's not that important: the test-case will probably

         crash on the first call to f with the bug present, or it will

         run wild including returning early (in y or here), so we also

         try and check the number of calls.  */

      || y (0) != v

      || y (3) != 0

      || y (-1) != 0

      || calls != 5)

    abort ();

  exit (0);

}