gcc/testsuite/gcc.dg/stack-check-2.c

   1 /* The goal here is to ensure that we never consider a call to a noreturn
   2    function as a potential tail call.
   3
   4    Right now GCC discovers potential tail calls by looking at the
   5    predecessors of the exit block.  A call to a non-return function
   6    has no successors and thus can never match that first filter.
   7
   8    But that could change one day and we want to catch it.  The problem
   9    is the compiler could potentially optimize a tail call to a nonreturn
  10    function, even if the caller has a frame.  That breaks the assumption
  11    that calls probe *sp when saving the return address that some targets
  12    depend on to elide stack probes.  */
  13
  14 /* { dg-do compile } */
  15 /* { dg-options "-O2 -fstack-clash-protection -fdump-tree-tailc -fdump-tree-optimized" } */
  16 /* { dg-require-effective-target supports_stack_clash_protection } */
  17
  18 extern void foo (void) __attribute__ ((__noreturn__));
  19
  20
  21 void
  22 test_direct_1 (void)
  23 {
  24   foo ();
  25 }
  26
  27 void
  28 test_direct_2 (void)
  29 {
  30   return foo ();
  31 }
  32
  33 void (*indirect)(void)__attribute__ ((noreturn));
  34
  35
  36 void
  37 test_indirect_1 ()
  38 {
  39   (*indirect)();
  40 }
  41
  42 void
  43 test_indirect_2 (void)
  44 {
  45   return (*indirect)();;
  46 }
  47
  48
  49 typedef void (*pvfn)() __attribute__ ((noreturn));
  50
  51 void (*indirect_casted)(void);
  52
  53 void
  54 test_indirect_casted_1 ()
  55 {
  56   (*(pvfn)indirect_casted)();
  57 }
  58
  59 void
  60 test_indirect_casted_2 (void)
  61 {
  62   return (*(pvfn)indirect_casted)();
  63 }
  64 /* { dg-final { scan-tree-dump-not "tail call" "tailc" } } */
  65 /* { dg-final { scan-tree-dump-not "tail call" "optimized" } } */
  66