| /* On targets where the call instruction is an implicit probe of *sp, we |
| elide stack probes as long as the size of the local stack is less than |
| PROBE_INTERVAL. |
| |
| But if the caller were to transform a tail call into a direct jump |
| we do not have that implicit probe. This normally isn't a problem as |
| the caller must not have a local frame for that optimization to apply. |
| |
| However, a sufficiently smart compiler could realize that the caller's |
| local stack need not be torn down and thus could transform a call into |
| a jump if the target is a noreturn function, even if the caller has |
| a local frame. |
| |
| To guard against that, targets that depend on *sp being probed by the |
| call itself must emit a probe if the target function is a noreturn |
| function, even if they just allocate a small amount of stack space. |
| |
| Rather than try to parse RTL or assembly code, we instead require the |
| prologue code to emit information into the dump file that we can |
| scan for. We scan for both the positive and negative cases. */ |
| |
| /* { dg-do compile } */ |
| /* { dg-options "-O2 -fstack-clash-protection -fdump-rtl-pro_and_epilogue -fno-optimize-sibling-calls" } */ |
| /* { dg-require-effective-target supports_stack_clash_protection } */ |
| |
| extern void arf (char *); |
| |
| __attribute__ ((noreturn)) void foo1 () |
| { |
| char x[10]; |
| while (1) |
| arf (x); |
| } |
| |
| void foo2 () |
| { |
| char x[10]; |
| arf (x); |
| } |
| /* { dg-final { scan-rtl-dump-times "Stack clash noreturn" 1 "pro_and_epilogue" } } */ |
| /* { dg-final { scan-rtl-dump-times "Stack clash not noreturn" 1 "pro_and_epilogue" } } */ |
| |
