/**********************************************************************
cont.c -
$Author$
$Date$
created at: Thu May 23 09:03:43 2007
Copyright (C) 2007 Koichi Sasada
**********************************************************************/
#include "ruby/ruby.h"
#include "yarvcore.h"
#include "gc.h"
#include "eval_intern.h"
typedef struct rb_context_struct {
VALUE self;
VALUE value;
VALUE prev; /* for fiber */
VALUE *vm_stack;
VALUE *machine_stack;
VALUE *machine_stack_src;
#ifdef __ia64
VALUE *machine_register_stack;
VALUE *machine_register_stack_src;
int machine_register_stack_size;
#endif
rb_thread_t saved_thread;
rb_jmpbuf_t jmpbuf;
int machine_stack_size;
int alive;
} rb_context_t;
VALUE rb_cCont;
VALUE rb_cFiber;
VALUE rb_eFiberError;
#define GetContPtr(obj, ptr) \
Data_Get_Struct(obj, rb_context_t, ptr)
NOINLINE(static VALUE cont_capture(volatile int *stat));
void rb_thread_mark(rb_thread_t *th);
static void
cont_mark(void *ptr)
{
RUBY_MARK_ENTER("cont");
if (ptr) {
rb_context_t *cont = ptr;
rb_gc_mark(cont->value);
rb_gc_mark(cont->prev);
rb_thread_mark(&cont->saved_thread);
if (cont->vm_stack) {
rb_gc_mark_locations(cont->vm_stack,
cont->vm_stack + cont->saved_thread.stack_size);
}
if (cont->machine_stack) {
rb_gc_mark_locations(cont->machine_stack,
cont->machine_stack + cont->machine_stack_size);
}
#ifdef __ia64
if (cont->machine_register_stack) {
rb_gc_mark_locations(cont->machine_register_stack,
cont->machine_register_stack + cont->machine_register_stack_size);
}
#endif
}
RUBY_MARK_LEAVE("cont");
}
static void
cont_free(void *ptr)
{
RUBY_FREE_ENTER("cont");
if (ptr) {
rb_context_t *cont = ptr;
RUBY_FREE_UNLESS_NULL(cont->saved_thread.stack);
RUBY_FREE_UNLESS_NULL(cont->machine_stack);
#ifdef __ia64
RUBY_FREE_UNLESS_NULL(cont->machine_register_stack);
#endif
RUBY_FREE_UNLESS_NULL(cont->vm_stack);
ruby_xfree(ptr);
}
RUBY_FREE_LEAVE("cont");
}
static void
cont_save_machine_stack(rb_thread_t *th, rb_context_t *cont)
{
int size;
rb_gc_set_stack_end(&th->machine_stack_end);
#ifdef __ia64
th->machine_register_stack_end = rb_ia64_bsp();
#endif
if (th->machine_stack_start > th->machine_stack_end) {
size = cont->machine_stack_size = th->machine_stack_start - th->machine_stack_end;
cont->machine_stack_src = th->machine_stack_end;
}
else {
size = cont->machine_stack_size = th->machine_stack_end - th->machine_stack_start;
cont->machine_stack_src = th->machine_stack_start;
}
if (cont->machine_stack) {
REALLOC_N(cont->machine_stack, VALUE, size);
}
else {
cont->machine_stack = ALLOC_N(VALUE, size);
}
MEMCPY(cont->machine_stack, cont->machine_stack_src, VALUE, size);
#ifdef __ia64
rb_ia64_flushrs();
size = cont->machine_register_stack_size = th->machine_register_stack_end - th->machine_register_stack_start;
cont->machine_register_stack_src = th->machine_register_stack_start;
if (cont->machine_register_stack) {
REALLOC_N(cont->machine_register_stack, VALUE, size);
}
else {
cont->machine_register_stack = ALLOC_N(VALUE, size);
}
MEMCPY(cont->machine_register_stack, cont->machine_register_stack_src, VALUE, size);
#endif
}
static rb_context_t *
cont_new(VALUE klass)
{
rb_context_t *cont;
volatile VALUE contval;
rb_thread_t *th = GET_THREAD(), *sth;
contval = Data_Make_Struct(klass, rb_context_t,
cont_mark, cont_free, cont);
RUBY_GC_INFO("cont alloc: %p (klass: %s)\n", cont,
klass == rb_cFiber ? "Fiber": "Continuation");
cont->self = contval;
cont->alive = Qtrue;
/* save context */
cont->saved_thread = *th;
sth = &cont->saved_thread;
return cont;
}
void vm_stack_to_heap(rb_thread_t *th);
static VALUE
cont_capture(volatile int *stat)
{
rb_context_t *cont;
rb_thread_t *th;
volatile VALUE contval;
vm_stack_to_heap(GET_THREAD());
cont = cont_new(rb_cCont);
contval = cont->self;
th = &cont->saved_thread;
cont->vm_stack = ALLOC_N(VALUE, th->stack_size);
MEMCPY(cont->vm_stack, th->stack, VALUE, th->stack_size);
th->stack = 0;
cont_save_machine_stack(th, cont);
if (ruby_setjmp(cont->jmpbuf)) {
VALUE value;
value = cont->value;
cont->value = Qnil;
*stat = 1;
return value;
}
else {
*stat = 0;
return cont->self;
}
}
NORETURN(static void cont_restore_1(rb_context_t *));
static void
cont_restore_1(rb_context_t *cont)
{
rb_thread_t *th = GET_THREAD(), *sth = &cont->saved_thread;
/* restore thread context */
if (sth->stack) {
/* fiber */
th->stack = sth->stack;
th->stack_size = sth->stack_size;
th->fiber = cont->self;
}
else {
/* continuation */
VALUE fval;
th->fiber = sth->fiber;
fval = th->fiber ? th->fiber : th->root_fiber;
if (fval) {
rb_context_t *fcont;
GetContPtr(fval, fcont);
th->stack_size = fcont->saved_thread.stack_size;
th->stack = fcont->saved_thread.stack;
}
MEMCPY(th->stack, cont->vm_stack, VALUE, sth->stack_size);
}
th->cfp = sth->cfp;
th->safe_level = sth->safe_level;
th->raised_flag = sth->raised_flag;
th->state = sth->state;
th->status = sth->status;
th->tag = sth->tag;
th->trap_tag = sth->trap_tag;
th->errinfo = sth->errinfo;
th->first_proc = sth->first_proc;
/* restore machine stack */
if (cont->machine_stack_src) {
MEMCPY(cont->machine_stack_src, cont->machine_stack,
VALUE, cont->machine_stack_size);
}
#ifdef __ia64
if (cont->machine_register_stack_src) {
MEMCPY(cont->machine_register_stack_src, cont->machine_register_stack,
VALUE, cont->machine_register_stack_size);
}
#endif
ruby_longjmp(cont->jmpbuf, 1);
}
NORETURN(NOINLINE(static void cont_restore_0(rb_context_t *, VALUE *)));
#ifdef __ia64
#define C(a) rse_##a##0, rse_##a##1, rse_##a##2, rse_##a##3, rse_##a##4
#define E(a) rse_##a##0= rse_##a##1= rse_##a##2= rse_##a##3= rse_##a##4
static volatile int C(a), C(b), C(c), C(d), C(e);
static volatile int C(f), C(g), C(h), C(i), C(j);
static volatile int C(k), C(l), C(m), C(n), C(o);
static volatile int C(p), C(q), C(r), C(s), C(t);
int rb_dummy_false = 0;
NORETURN(NOINLINE(static void register_stack_extend(rb_context_t *, VALUE *)));
static void
register_stack_extend(rb_context_t *cont, VALUE *curr_bsp)
{
if (rb_dummy_false) {
/* use registers as much as possible */
E(a) = E(b) = E(c) = E(d) = E(e) =
E(f) = E(g) = E(h) = E(i) = E(j) =
E(k) = E(l) = E(m) = E(n) = E(o) =
E(p) = E(q) = E(r) = E(s) = E(t) = 0;
E(a) = E(b) = E(c) = E(d) = E(e) =
E(f) = E(g) = E(h) = E(i) = E(j) =
E(k) = E(l) = E(m) = E(n) = E(o) =
E(p) = E(q) = E(r) = E(s) = E(t) = 0;
}
if (curr_bsp < cont->machine_register_stack_src+cont->machine_register_stack_size) {
register_stack_extend(cont, (VALUE*)rb_ia64_bsp());
}
cont_restore_1(cont);
}
#undef C
#undef E
#endif
static void
cont_restore_0(rb_context_t *cont, VALUE *addr_in_prev_frame)
{
if (cont->machine_stack_src) {
#define STACK_PAD_SIZE 1024
VALUE space[STACK_PAD_SIZE];
#if STACK_GROW_DIRECTION < 0 /* downward */
if (addr_in_prev_frame > cont->machine_stack_src) {
cont_restore_0(cont, &space[0]);
}
#elif STACK_GROW_DIRECTION > 0 /* upward */
if (addr_in_prev_frame < cont->machine_stack_src + cont->machine_stack_size) {
cont_restore_0(cont, &space[STACK_PAD_SIZE-1]);
}
#else
if (addr_in_prev_frame > &space[0]) {
/* Stack grows downward */
if (addr_in_prev_frame > cont->saved_thread.machine_stack_src) {
cont_restore_0(cont, &space[0]);
}
}
else {
/* Stack grows upward */
if (addr_in_prev_frame < cont->machine_stack_src + cont->machine_stack_size) {
cont_restore_0(cont, &space[STACK_PAD_SIZE-1]);
}
}
#endif
}
#ifdef __ia64
register_stack_extend(cont, (VALUE*)rb_ia64_bsp());
#else
cont_restore_1(cont);
#endif
}
/*
* Document-class: Continuation
*
* Continuation objects are generated by
* Kernel#callcc
. They hold a return address and execution
* context, allowing a nonlocal return to the end of the
* callcc
block from anywhere within a program.
* Continuations are somewhat analogous to a structured version of C's
* setjmp/longjmp
(although they contain more state, so
* you might consider them closer to threads).
*
* For instance:
*
* arr = [ "Freddie", "Herbie", "Ron", "Max", "Ringo" ]
* callcc{|$cc|}
* puts(message = arr.shift)
* $cc.call unless message =~ /Max/
*
* produces:
*
* Freddie
* Herbie
* Ron
* Max
*
* This (somewhat contrived) example allows the inner loop to abandon
* processing early:
*
* callcc {|cont|
* for i in 0..4
* print "\n#{i}: "
* for j in i*5...(i+1)*5
* cont.call() if j == 17
* printf "%3d", j
* end
* end
* }
* print "\n"
*
* produces:
*
* 0: 0 1 2 3 4
* 1: 5 6 7 8 9
* 2: 10 11 12 13 14
* 3: 15 16
*/
/*
* call-seq:
* callcc {|cont| block } => obj
*
* Generates a Continuation
object, which it passes to the
* associated block. Performing a cont.call
will
* cause the callcc
to return (as will falling through the
* end of the block). The value returned by the callcc
is
* the value of the block, or the value passed to
* cont.call
. See class Continuation
* for more details. Also see Kernel::throw
for
* an alternative mechanism for unwinding a call stack.
*/
static VALUE
rb_callcc(VALUE self)
{
volatile int called;
volatile VALUE val = cont_capture(&called);
if (called) {
return val;
}
else {
return rb_yield(val);
}
}
static VALUE
make_passing_arg(int argc, VALUE *argv)
{
switch(argc) {
case 0:
return Qnil;
case 1:
return argv[0];
default:
return rb_ary_new4(argc, argv);
}
}
/*
* call-seq:
* cont.call(args, ...)
* cont[args, ...]
*
* Invokes the continuation. The program continues from the end of the
* callcc
block. If no arguments are given, the original
* callcc
returns nil
. If one argument is
* given, callcc
returns it. Otherwise, an array
* containing args is returned.
*
* callcc {|cont| cont.call } #=> nil
* callcc {|cont| cont.call 1 } #=> 1
* callcc {|cont| cont.call 1, 2, 3 } #=> [1, 2, 3]
*/
static VALUE
rb_cont_call(int argc, VALUE *argv, VALUE contval)
{
rb_context_t *cont;
rb_thread_t *th = GET_THREAD();
GetContPtr(contval, cont);
if (cont->saved_thread.self != th->self) {
rb_raise(rb_eRuntimeError, "continuation called across threads");
}
if (cont->saved_thread.trap_tag != th->trap_tag) {
rb_raise(rb_eRuntimeError, "continuation called across trap");
}
if (cont->saved_thread.fiber) {
rb_context_t *fcont;
GetContPtr(cont->saved_thread.fiber, fcont);
if (th->fiber != cont->saved_thread.fiber) {
rb_raise(rb_eRuntimeError, "continuation called across fiber");
}
if (!fcont->alive) {
rb_raise(rb_eRuntimeError, "continuation called dead fiber");
}
}
cont->value = make_passing_arg(argc, argv);
cont_restore_0(cont, (VALUE *)&cont);
return Qnil; /* unreachable */
}
/*********/
/* fiber */
/*********/
#define FIBER_STACK_SIZE (4 * 1024)
static VALUE
rb_fiber_s_new(VALUE self)
{
rb_context_t *cont = cont_new(self);
VALUE contval = cont->self;
rb_thread_t *th = &cont->saved_thread;
/* initialize */
cont->prev = Qnil;
cont->vm_stack = 0;
th->stack = 0;
th->stack_size = FIBER_STACK_SIZE;
th->stack = ALLOC_N(VALUE, th->stack_size);
MEMZERO(th->stack, VALUE, th->stack_size);
th->cfp = (void *)(th->stack + th->stack_size);
th->cfp--;
th->cfp->pc = 0;
th->cfp->sp = th->stack + 1;
th->cfp->bp = 0;
th->cfp->lfp = th->stack;
*th->cfp->lfp = 0;
th->cfp->dfp = th->stack;
th->cfp->self = Qnil;
th->cfp->magic = 0;
th->cfp->iseq = 0;
th->cfp->proc = 0;
th->cfp->block_iseq = 0;
th->first_proc = rb_block_proc();
MEMCPY(&cont->jmpbuf, &th->root_jmpbuf, rb_jmpbuf_t, 1);
return contval;
}
static VALUE rb_fiber_yield(int argc, VALUE *args, VALUE fval);
static void
rb_fiber_terminate(rb_context_t *cont)
{
rb_context_t *prev_cont;
VALUE value = cont->value;
GetContPtr(cont->prev, prev_cont);
cont->alive = Qfalse;
if (prev_cont->alive == Qfalse) {
rb_fiber_yield(1, &value, GET_THREAD()->root_fiber);
}
else {
rb_fiber_yield(1, &value, cont->prev);
}
}
void
rb_fiber_start(void)
{
rb_thread_t *th = GET_THREAD();
rb_context_t *cont;
rb_proc_t *proc;
VALUE args;
int state;
TH_PUSH_TAG(th);
if ((state = EXEC_TAG()) == 0) {
GetContPtr(th->fiber, cont);
GetProcPtr(cont->saved_thread.first_proc, proc);
args = cont->value;
cont->value = Qnil;
th->errinfo = Qnil;
th->local_lfp = proc->block.lfp;
th->local_svar = Qnil;
cont->value = vm_invoke_proc(th, proc, proc->block.self, 1, &args);
}
TH_POP_TAG();
if (state) {
th->thrown_errinfo = vm_make_jump_tag_but_local_jump(state, th->errinfo);
th->interrupt_flag = 1;
}
rb_fiber_terminate(cont);
rb_bug("rb_fiber_start: unreachable");
}
static VALUE
rb_fiber_current(rb_thread_t *th)
{
if (th->fiber == 0) {
/* save root */
th->root_fiber = th->fiber = cont_new(rb_cFiber)->self;
}
return th->fiber;
}
static VALUE
cont_store(rb_context_t *next_cont)
{
rb_thread_t *th = GET_THREAD();
rb_context_t *cont;
if (th->fiber) {
GetContPtr(th->fiber, cont);
cont->saved_thread = *th;
}
else {
/* create current fiber */
cont = cont_new(rb_cFiber); /* no need to allocate vm stack */
th->root_fiber = th->fiber = cont->self;
}
if (cont->alive) {
next_cont->prev = cont->self;
}
cont_save_machine_stack(th, cont);
if (ruby_setjmp(cont->jmpbuf)) {
/* restored */
GetContPtr(th->fiber, cont);
return cont->value;
}
else {
return Qundef;
}
}
static VALUE
rb_fiber_yield(int argc, VALUE *argv, VALUE fval)
{
VALUE value;
rb_context_t *cont;
rb_thread_t *th = GET_THREAD();
GetContPtr(fval, cont);
if (cont->saved_thread.self != th->self) {
rb_raise(rb_eFiberError, "fiber called across threads");
}
if (cont->saved_thread.trap_tag != th->trap_tag) {
rb_raise(rb_eFiberError, "fiber called across trap");
}
if (!cont->alive) {
rb_raise(rb_eFiberError, "dead fiber called");
}
cont->value = make_passing_arg(argc, argv);
if ((value = cont_store(cont)) == Qundef) {
cont_restore_0(cont, (VALUE *)&cont);
rb_bug("rb_fiber_yield: unreachable");
}
return value;
}
static VALUE
rb_fiber_prev(VALUE fval)
{
rb_context_t *cont;
GetContPtr(fval, cont);
return cont->prev;
}
static VALUE
rb_fiber_alive_p(VALUE fval)
{
rb_context_t *cont;
GetContPtr(fval, cont);
return cont->alive;
}
static VALUE
rb_fiber_s_current(VALUE klass)
{
return rb_fiber_current(GET_THREAD());
}
static VALUE
rb_fiber_s_prev(VALUE klass)
{
return rb_fiber_prev(rb_fiber_s_current(Qnil));
}
static VALUE
rb_fiber_s_yield(int argc, VALUE *argv, VALUE fval)
{
return rb_fiber_yield(argc, argv, rb_fiber_s_prev(Qnil));
}
void
Init_Cont(void)
{
rb_cCont = rb_define_class("Continuation", rb_cObject);
rb_undef_alloc_func(rb_cCont);
rb_undef_method(CLASS_OF(rb_cCont), "new");
rb_define_method(rb_cCont, "call", rb_cont_call, -1);
rb_define_method(rb_cCont, "[]", rb_cont_call, -1);
rb_define_global_function("callcc", rb_callcc, 0);
rb_cFiber = rb_define_class("Fiber", rb_cObject);
rb_undef_alloc_func(rb_cFiber);
rb_define_method(rb_cFiber, "yield", rb_fiber_yield, -1);
rb_define_method(rb_cFiber, "prev", rb_fiber_prev, 0);
rb_define_method(rb_cFiber, "alive?", rb_fiber_alive_p, 0);
rb_define_singleton_method(rb_cFiber, "current", rb_fiber_s_current, 0);
rb_define_singleton_method(rb_cFiber, "prev", rb_fiber_s_prev, 0);
rb_define_singleton_method(rb_cFiber, "yield", rb_fiber_s_yield, -1);
rb_define_singleton_method(rb_cFiber, "new", rb_fiber_s_new, 0);
rb_eFiberError = rb_define_class("FiberError", rb_eStandardError);
}