Miscellaneous runtime library routines

Cache control functions

void __clear_cache(char *beg, char *end)

This function clears the instruction cache between beg and end.

Split stack functions and variables

void *__splitstack_find(void *segment_arg, void *sp, size_t len, void **next_segment, void **next_sp, void **initial_sp)

When using -fsplit-stack, this call may be used to iterate over the stack segments. It may be called like this:

void *next_segment = NULL;
void *next_sp = NULL;
void *initial_sp = NULL;
void *stack;
size_t stack_size;
while ((stack = __splitstack_find (next_segment, next_sp,
                                   &stack_size, &next_segment,
                                   &next_sp, &initial_sp))
       != NULL)
  {
    /* Stack segment starts at stack and is
       stack_size bytes long.  */
  }

There is no way to iterate over the stack segments of a different thread. However, what is permitted is for one thread to call this with the segment_arg and sp arguments NULL, to pass next_segment, next_sp, and initial_sp to a different thread, and then to suspend one way or another. A different thread may run the subsequent __splitstack_find iterations. Of course, this will only work if the first thread is suspended while the second thread is calling __splitstack_find. If not, the second thread could be looking at the stack while it is changing, and anything could happen.

struct stack_segment *__morestack_segments

stack_segment *__morestack_current_segment

struct initial_sp __morestack_initial_sp

Internal variables used by the -fsplit-stack implementation.