modernc.org/ccgo/v3@v3.16.14/lib/testdata/gcc-9.1.0/gcc/testsuite/gcc.c-torture/execute/pr17377.c (about)

     1  /* PR target/17377
     2     Bug in code emitted by "return" pattern on CRIS: missing pop of
     3     forced return address on stack.  */
     4  /* { dg-require-effective-target return_address } */
     5  int calls = 0;
     6  
     7  void *f (int) __attribute__ ((__noinline__));
     8  void *
     9  f (int i)
    10  {
    11    /* The code does a little brittle song and dance to trig the "return"
    12       pattern instead of the function epilogue.  This must still be a
    13       leaf function for the bug to be exposed.  */
    14  
    15    if (calls++ == 0)
    16      return __builtin_return_address (0);
    17  
    18    switch (i)
    19      {
    20      case 1:
    21        return f;
    22      case 0:
    23        return __builtin_return_address (0);
    24      }
    25    return 0;
    26  }
    27  
    28  int x;
    29  
    30  void *y (int i) __attribute__ ((__noinline__,__noclone__));
    31  void *
    32  y (int i)
    33  {
    34    x = 0;
    35  
    36    /* This must not be a sibling call: the return address must appear
    37       constant for different calls to this function.  Postincrementing x
    38       catches otherwise unidentified multiple returns (e.g. through the
    39       return-address register and then this epilogue popping the address
    40       stored on stack in "f").  */
    41    return (char *) f (i) + x++;
    42  }
    43  
    44  int
    45  main (void)
    46  {
    47    void *v = y (4);
    48    if (y (1) != f
    49        /* Can't reasonably check the validity of the return address
    50  	 above, but it's not that important: the test-case will probably
    51  	 crash on the first call to f with the bug present, or it will
    52  	 run wild including returning early (in y or here), so we also
    53  	 try and check the number of calls.  */
    54        || y (0) != v
    55        || y (3) != 0
    56        || y (-1) != 0
    57        || calls != 5)
    58      abort ();
    59    exit (0);
    60  }