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 }