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/**********************************************************************
cont.c -
$Author$
created at: Thu May 23 09:03:43 2007
Copyright (C) 2007 Koichi Sasada
**********************************************************************/
#include "ruby/internal/config.h"
#ifndef _WIN32
#include <unistd.h>
#include <sys/mman.h>
#endif
#include COROUTINE_H
#include "eval_intern.h"
#include "gc.h"
#include "internal.h"
#include "internal/cont.h"
#include "internal/proc.h"
#include "internal/warnings.h"
#include "internal/scheduler.h"
#include "mjit.h"
#include "vm_core.h"
#include "id_table.h"
#include "ractor_core.h"
static const int DEBUG = 0;
#define RB_PAGE_SIZE (pagesize)
#define RB_PAGE_MASK (~(RB_PAGE_SIZE - 1))
static long pagesize;
static const rb_data_type_t cont_data_type, fiber_data_type;
static VALUE rb_cContinuation;
static VALUE rb_cFiber;
static VALUE rb_eFiberError;
#ifdef RB_EXPERIMENTAL_FIBER_POOL
static VALUE rb_cFiberPool;
#endif
#define CAPTURE_JUST_VALID_VM_STACK 1
// Defined in `coroutine/$arch/Context.h`:
#ifdef COROUTINE_LIMITED_ADDRESS_SPACE
#define FIBER_POOL_ALLOCATION_FREE
#define FIBER_POOL_INITIAL_SIZE 8
#define FIBER_POOL_ALLOCATION_MAXIMUM_SIZE 32
#else
#define FIBER_POOL_INITIAL_SIZE 32
#define FIBER_POOL_ALLOCATION_MAXIMUM_SIZE 1024
#endif
enum context_type {
CONTINUATION_CONTEXT = 0,
FIBER_CONTEXT = 1
};
struct cont_saved_vm_stack {
VALUE *ptr;
#ifdef CAPTURE_JUST_VALID_VM_STACK
size_t slen; /* length of stack (head of ec->vm_stack) */
size_t clen; /* length of control frames (tail of ec->vm_stack) */
#endif
};
struct fiber_pool;
// Represents a single stack.
struct fiber_pool_stack {
// A pointer to the memory allocation (lowest address) for the stack.
void * base;
// The current stack pointer, taking into account the direction of the stack.
void * current;
// The size of the stack excluding any guard pages.
size_t size;
// The available stack capacity w.r.t. the current stack offset.
size_t available;
// The pool this stack should be allocated from.
struct fiber_pool * pool;
// If the stack is allocated, the allocation it came from.
struct fiber_pool_allocation * allocation;
};
// A linked list of vacant (unused) stacks.
// This structure is stored in the first page of a stack if it is not in use.
// @sa fiber_pool_vacancy_pointer
struct fiber_pool_vacancy {
// Details about the vacant stack:
struct fiber_pool_stack stack;
// The vacancy linked list.
#ifdef FIBER_POOL_ALLOCATION_FREE
struct fiber_pool_vacancy * previous;
#endif
struct fiber_pool_vacancy * next;
};
// Manages singly linked list of mapped regions of memory which contains 1 more more stack:
//
// base = +-------------------------------+-----------------------+ +
// |VM Stack |VM Stack | | |
// | | | | |
// | | | | |
// +-------------------------------+ | |
// |Machine Stack |Machine Stack | | |
// | | | | |
// | | | | |
// | | | . . . . | | size
// | | | | |
// | | | | |
// | | | | |
// | | | | |
// | | | | |
// +-------------------------------+ | |
// |Guard Page |Guard Page | | |
// +-------------------------------+-----------------------+ v
//
// +------------------------------------------------------->
//
// count
//
struct fiber_pool_allocation {
// A pointer to the memory mapped region.
void * base;
// The size of the individual stacks.
size_t size;
// The stride of individual stacks (including any guard pages or other accounting details).
size_t stride;
// The number of stacks that were allocated.
size_t count;
#ifdef FIBER_POOL_ALLOCATION_FREE
// The number of stacks used in this allocation.
size_t used;
#endif
struct fiber_pool * pool;
// The allocation linked list.
#ifdef FIBER_POOL_ALLOCATION_FREE
struct fiber_pool_allocation * previous;
#endif
struct fiber_pool_allocation * next;
};
// A fiber pool manages vacant stacks to reduce the overhead of creating fibers.
struct fiber_pool {
// A singly-linked list of allocations which contain 1 or more stacks each.
struct fiber_pool_allocation * allocations;
// Provides O(1) stack "allocation":
struct fiber_pool_vacancy * vacancies;
// The size of the stack allocations (excluding any guard page).
size_t size;
// The total number of stacks that have been allocated in this pool.
size_t count;
// The initial number of stacks to allocate.
size_t initial_count;
// Whether to madvise(free) the stack or not:
int free_stacks;
// The number of stacks that have been used in this pool.
size_t used;
// The amount to allocate for the vm_stack:
size_t vm_stack_size;
};
typedef struct rb_context_struct {
enum context_type type;
int argc;
int kw_splat;
VALUE self;
VALUE value;
struct cont_saved_vm_stack saved_vm_stack;
struct {
VALUE *stack;
VALUE *stack_src;
size_t stack_size;
} machine;
rb_execution_context_t saved_ec;
rb_jmpbuf_t jmpbuf;
rb_ensure_entry_t *ensure_array;
/* Pointer to MJIT info about the continuation. */
struct mjit_cont *mjit_cont;
} rb_context_t;
/*
* Fiber status:
* [Fiber.new] ------> FIBER_CREATED
* | [Fiber#resume]
* v
* +--> FIBER_RESUMED ----+
* [Fiber#resume] | | [Fiber.yield] |
* | v |
* +-- FIBER_SUSPENDED | [Terminate]
* |
* FIBER_TERMINATED <-+
*/
enum fiber_status {
FIBER_CREATED,
FIBER_RESUMED,
FIBER_SUSPENDED,
FIBER_TERMINATED
};
#define FIBER_CREATED_P(fiber) ((fiber)->status == FIBER_CREATED)
#define FIBER_RESUMED_P(fiber) ((fiber)->status == FIBER_RESUMED)
#define FIBER_SUSPENDED_P(fiber) ((fiber)->status == FIBER_SUSPENDED)
#define FIBER_TERMINATED_P(fiber) ((fiber)->status == FIBER_TERMINATED)
#define FIBER_RUNNABLE_P(fiber) (FIBER_CREATED_P(fiber) || FIBER_SUSPENDED_P(fiber))
struct rb_fiber_struct {
rb_context_t cont;
VALUE first_proc;
struct rb_fiber_struct *prev;
VALUE resuming_fiber;
BITFIELD(enum fiber_status, status, 2);
/* Whether the fiber is allowed to implicitly yield. */
unsigned int yielding : 1;
unsigned int blocking : 1;
struct coroutine_context context;
struct fiber_pool_stack stack;
};
static struct fiber_pool shared_fiber_pool = {NULL, NULL, 0, 0, 0, 0};
static ID fiber_initialize_keywords[2] = {0};
/*
* FreeBSD require a first (i.e. addr) argument of mmap(2) is not NULL
* if MAP_STACK is passed.
* http://www.FreeBSD.org/cgi/query-pr.cgi?pr=158755
*/
#if defined(MAP_STACK) && !defined(__FreeBSD__) && !defined(__FreeBSD_kernel__)
#define FIBER_STACK_FLAGS (MAP_PRIVATE | MAP_ANON | MAP_STACK)
#else
#define FIBER_STACK_FLAGS (MAP_PRIVATE | MAP_ANON)
#endif
#define ERRNOMSG strerror(errno)
// Locates the stack vacancy details for the given stack.
// Requires that fiber_pool_vacancy fits within one page.
inline static struct fiber_pool_vacancy *
fiber_pool_vacancy_pointer(void * base, size_t size)
{
STACK_GROW_DIR_DETECTION;
return (struct fiber_pool_vacancy *)(
(char*)base + STACK_DIR_UPPER(0, size - RB_PAGE_SIZE)
);
}
// Reset the current stack pointer and available size of the given stack.
inline static void
fiber_pool_stack_reset(struct fiber_pool_stack * stack)
{
STACK_GROW_DIR_DETECTION;
stack->current = (char*)stack->base + STACK_DIR_UPPER(0, stack->size);
stack->available = stack->size;
}
// A pointer to the base of the current unused portion of the stack.
inline static void *
fiber_pool_stack_base(struct fiber_pool_stack * stack)
{
STACK_GROW_DIR_DETECTION;
VM_ASSERT(stack->current);
return STACK_DIR_UPPER(stack->current, (char*)stack->current - stack->available);
}
// Allocate some memory from the stack. Used to allocate vm_stack inline with machine stack.
// @sa fiber_initialize_coroutine
inline static void *
fiber_pool_stack_alloca(struct fiber_pool_stack * stack, size_t offset)
{
STACK_GROW_DIR_DETECTION;
if (DEBUG) fprintf(stderr, "fiber_pool_stack_alloca(%p): %"PRIuSIZE"/%"PRIuSIZE"\n", (void*)stack, offset, stack->available);
VM_ASSERT(stack->available >= offset);
// The pointer to the memory being allocated:
void * pointer = STACK_DIR_UPPER(stack->current, (char*)stack->current - offset);
// Move the stack pointer:
stack->current = STACK_DIR_UPPER((char*)stack->current + offset, (char*)stack->current - offset);
stack->available -= offset;
return pointer;
}
// Reset the current stack pointer and available size of the given stack.
inline static void
fiber_pool_vacancy_reset(struct fiber_pool_vacancy * vacancy)
{
fiber_pool_stack_reset(&vacancy->stack);
// Consume one page of the stack because it's used for the vacancy list:
fiber_pool_stack_alloca(&vacancy->stack, RB_PAGE_SIZE);
}
inline static struct fiber_pool_vacancy *
fiber_pool_vacancy_push(struct fiber_pool_vacancy * vacancy, struct fiber_pool_vacancy * head)
{
vacancy->next = head;
#ifdef FIBER_POOL_ALLOCATION_FREE
if (head) {
head->previous = vacancy;
vacancy->previous = NULL;
}
#endif
return vacancy;
}
#ifdef FIBER_POOL_ALLOCATION_FREE
static void
fiber_pool_vacancy_remove(struct fiber_pool_vacancy * vacancy)
{
if (vacancy->next) {
vacancy->next->previous = vacancy->previous;
}
if (vacancy->previous) {
vacancy->previous->next = vacancy->next;
}
else {
// It's the head of the list:
vacancy->stack.pool->vacancies = vacancy->next;
}
}
inline static struct fiber_pool_vacancy *
fiber_pool_vacancy_pop(struct fiber_pool * pool)
{
struct fiber_pool_vacancy * vacancy = pool->vacancies;
if (vacancy) {
fiber_pool_vacancy_remove(vacancy);
}
return vacancy;
}
#else
inline static struct fiber_pool_vacancy *
fiber_pool_vacancy_pop(struct fiber_pool * pool)
{
struct fiber_pool_vacancy * vacancy = pool->vacancies;
if (vacancy) {
pool->vacancies = vacancy->next;
}
return vacancy;
}
#endif
// Initialize the vacant stack. The [base, size] allocation should not include the guard page.
// @param base The pointer to the lowest address of the allocated memory.
// @param size The size of the allocated memory.
inline static struct fiber_pool_vacancy *
fiber_pool_vacancy_initialize(struct fiber_pool * fiber_pool, struct fiber_pool_vacancy * vacancies, void * base, size_t size)
{
struct fiber_pool_vacancy * vacancy = fiber_pool_vacancy_pointer(base, size);
vacancy->stack.base = base;
vacancy->stack.size = size;
fiber_pool_vacancy_reset(vacancy);
vacancy->stack.pool = fiber_pool;
return fiber_pool_vacancy_push(vacancy, vacancies);
}
// Allocate a maximum of count stacks, size given by stride.
// @param count the number of stacks to allocate / were allocated.
// @param stride the size of the individual stacks.
// @return [void *] the allocated memory or NULL if allocation failed.
inline static void *
fiber_pool_allocate_memory(size_t * count, size_t stride)
{
// We use a divide-by-2 strategy to try and allocate memory. We are trying
// to allocate `count` stacks. In normal situation, this won't fail. But
// if we ran out of address space, or we are allocating more memory than
// the system would allow (e.g. overcommit * physical memory + swap), we
// divide count by two and try again. This condition should only be
// encountered in edge cases, but we handle it here gracefully.
while (*count > 1) {
#if defined(_WIN32)
void * base = VirtualAlloc(0, (*count)*stride, MEM_COMMIT, PAGE_READWRITE);
if (!base) {
*count = (*count) >> 1;
}
else {
return base;
}
#else
errno = 0;
void * base = mmap(NULL, (*count)*stride, PROT_READ | PROT_WRITE, FIBER_STACK_FLAGS, -1, 0);
if (base == MAP_FAILED) {
// If the allocation fails, count = count / 2, and try again.
*count = (*count) >> 1;
}
else {
return base;
}
#endif
}
return NULL;
}
// Given an existing fiber pool, expand it by the specified number of stacks.
// @param count the maximum number of stacks to allocate.
// @return the allocated fiber pool.
// @sa fiber_pool_allocation_free
static struct fiber_pool_allocation *
fiber_pool_expand(struct fiber_pool * fiber_pool, size_t count)
{
STACK_GROW_DIR_DETECTION;
size_t size = fiber_pool->size;
size_t stride = size + RB_PAGE_SIZE;
// Allocate the memory required for the stacks:
void * base = fiber_pool_allocate_memory(&count, stride);
if (base == NULL) {
rb_raise(rb_eFiberError, "can't alloc machine stack to fiber (%"PRIuSIZE" x %"PRIuSIZE" bytes): %s", count, size, ERRNOMSG);
}
struct fiber_pool_vacancy * vacancies = fiber_pool->vacancies;
struct fiber_pool_allocation * allocation = RB_ALLOC(struct fiber_pool_allocation);
// Initialize fiber pool allocation:
allocation->base = base;
allocation->size = size;
allocation->stride = stride;
allocation->count = count;
#ifdef FIBER_POOL_ALLOCATION_FREE
allocation->used = 0;
#endif
allocation->pool = fiber_pool;
if (DEBUG) {
fprintf(stderr, "fiber_pool_expand(%"PRIuSIZE"): %p, %"PRIuSIZE"/%"PRIuSIZE" x [%"PRIuSIZE":%"PRIuSIZE"]\n",
count, (void*)fiber_pool, fiber_pool->used, fiber_pool->count, size, fiber_pool->vm_stack_size);
}
// Iterate over all stacks, initializing the vacancy list:
for (size_t i = 0; i < count; i += 1) {
void * base = (char*)allocation->base + (stride * i);
void * page = (char*)base + STACK_DIR_UPPER(size, 0);
#if defined(_WIN32)
DWORD old_protect;
if (!VirtualProtect(page, RB_PAGE_SIZE, PAGE_READWRITE | PAGE_GUARD, &old_protect)) {
VirtualFree(allocation->base, 0, MEM_RELEASE);
rb_raise(rb_eFiberError, "can't set a guard page: %s", ERRNOMSG);
}
#else
if (mprotect(page, RB_PAGE_SIZE, PROT_NONE) < 0) {
munmap(allocation->base, count*stride);
rb_raise(rb_eFiberError, "can't set a guard page: %s", ERRNOMSG);
}
#endif
vacancies = fiber_pool_vacancy_initialize(
fiber_pool, vacancies,
(char*)base + STACK_DIR_UPPER(0, RB_PAGE_SIZE),
size
);
#ifdef FIBER_POOL_ALLOCATION_FREE
vacancies->stack.allocation = allocation;
#endif
}
// Insert the allocation into the head of the pool:
allocation->next = fiber_pool->allocations;
#ifdef FIBER_POOL_ALLOCATION_FREE
if (allocation->next) {
allocation->next->previous = allocation;
}
allocation->previous = NULL;
#endif
fiber_pool->allocations = allocation;
fiber_pool->vacancies = vacancies;
fiber_pool->count += count;
return allocation;
}
// Initialize the specified fiber pool with the given number of stacks.
// @param vm_stack_size The size of the vm stack to allocate.
static void
fiber_pool_initialize(struct fiber_pool * fiber_pool, size_t size, size_t count, size_t vm_stack_size)
{
VM_ASSERT(vm_stack_size < size);
fiber_pool->allocations = NULL;
fiber_pool->vacancies = NULL;
fiber_pool->size = ((size / RB_PAGE_SIZE) + 1) * RB_PAGE_SIZE;
fiber_pool->count = 0;
fiber_pool->initial_count = count;
fiber_pool->free_stacks = 1;
fiber_pool->used = 0;
fiber_pool->vm_stack_size = vm_stack_size;
fiber_pool_expand(fiber_pool, count);
}
#ifdef FIBER_POOL_ALLOCATION_FREE
// Free the list of fiber pool allocations.
static void
fiber_pool_allocation_free(struct fiber_pool_allocation * allocation)
{
STACK_GROW_DIR_DETECTION;
VM_ASSERT(allocation->used == 0);
if (DEBUG) fprintf(stderr, "fiber_pool_allocation_free: %p base=%p count=%"PRIuSIZE"\n", allocation, allocation->base, allocation->count);
size_t i;
for (i = 0; i < allocation->count; i += 1) {
void * base = (char*)allocation->base + (allocation->stride * i) + STACK_DIR_UPPER(0, RB_PAGE_SIZE);
struct fiber_pool_vacancy * vacancy = fiber_pool_vacancy_pointer(base, allocation->size);
// Pop the vacant stack off the free list:
fiber_pool_vacancy_remove(vacancy);
}
#ifdef _WIN32
VirtualFree(allocation->base, 0, MEM_RELEASE);
#else
munmap(allocation->base, allocation->stride * allocation->count);
#endif
if (allocation->previous) {
allocation->previous->next = allocation->next;
}
else {
// We are the head of the list, so update the pool:
allocation->pool->allocations = allocation->next;
}
if (allocation->next) {
allocation->next->previous = allocation->previous;
}
allocation->pool->count -= allocation->count;
ruby_xfree(allocation);
}
#endif
// Acquire a stack from the given fiber pool. If none are available, allocate more.
static struct fiber_pool_stack
fiber_pool_stack_acquire(struct fiber_pool * fiber_pool)
{
struct fiber_pool_vacancy * vacancy = fiber_pool_vacancy_pop(fiber_pool);
if (DEBUG) fprintf(stderr, "fiber_pool_stack_acquire: %p used=%"PRIuSIZE"\n", (void*)fiber_pool->vacancies, fiber_pool->used);
if (!vacancy) {
const size_t maximum = FIBER_POOL_ALLOCATION_MAXIMUM_SIZE;
const size_t minimum = fiber_pool->initial_count;
size_t count = fiber_pool->count;
if (count > maximum) count = maximum;
if (count < minimum) count = minimum;
fiber_pool_expand(fiber_pool, count);
// The free list should now contain some stacks:
VM_ASSERT(fiber_pool->vacancies);
vacancy = fiber_pool_vacancy_pop(fiber_pool);
}
VM_ASSERT(vacancy);
VM_ASSERT(vacancy->stack.base);
// Take the top item from the free list:
fiber_pool->used += 1;
#ifdef FIBER_POOL_ALLOCATION_FREE
vacancy->stack.allocation->used += 1;
#endif
fiber_pool_stack_reset(&vacancy->stack);
return vacancy->stack;
}
// We advise the operating system that the stack memory pages are no longer being used.
// This introduce some performance overhead but allows system to relaim memory when there is pressure.
static inline void
fiber_pool_stack_free(struct fiber_pool_stack * stack)
{
void * base = fiber_pool_stack_base(stack);
size_t size = stack->available;
// If this is not true, the vacancy information will almost certainly be destroyed:
VM_ASSERT(size <= (stack->size - RB_PAGE_SIZE));
if (DEBUG) fprintf(stderr, "fiber_pool_stack_free: %p+%"PRIuSIZE" [base=%p, size=%"PRIuSIZE"]\n", base, size, stack->base, stack->size);
#if VM_CHECK_MODE > 0 && defined(MADV_DONTNEED)
// This immediately discards the pages and the memory is reset to zero.
madvise(base, size, MADV_DONTNEED);
#elif defined(MADV_FREE_REUSABLE)
madvise(base, size, MADV_FREE_REUSABLE);
#elif defined(MADV_FREE)
madvise(base, size, MADV_FREE);
#elif defined(MADV_DONTNEED)
madvise(base, size, MADV_DONTNEED);
#elif defined(_WIN32)
VirtualAlloc(base, size, MEM_RESET, PAGE_READWRITE);
// Not available in all versions of Windows.
//DiscardVirtualMemory(base, size);
#endif
}
// Release and return a stack to the vacancy list.
static void
fiber_pool_stack_release(struct fiber_pool_stack * stack)
{
struct fiber_pool * pool = stack->pool;
struct fiber_pool_vacancy * vacancy = fiber_pool_vacancy_pointer(stack->base, stack->size);
if (DEBUG) fprintf(stderr, "fiber_pool_stack_release: %p used=%"PRIuSIZE"\n", stack->base, stack->pool->used);
// Copy the stack details into the vacancy area:
vacancy->stack = *stack;
// After this point, be careful about updating/using state in stack, since it's copied to the vacancy area.
// Reset the stack pointers and reserve space for the vacancy data:
fiber_pool_vacancy_reset(vacancy);
// Push the vacancy into the vancancies list:
pool->vacancies = fiber_pool_vacancy_push(vacancy, stack->pool->vacancies);
pool->used -= 1;
#ifdef FIBER_POOL_ALLOCATION_FREE
struct fiber_pool_allocation * allocation = stack->allocation;
allocation->used -= 1;
// Release address space and/or dirty memory:
if (allocation->used == 0) {
fiber_pool_allocation_free(allocation);
}
else if (stack->pool->free_stacks) {
fiber_pool_stack_free(&vacancy->stack);
}
#else
// This is entirely optional, but clears the dirty flag from the stack memory, so it won't get swapped to disk when there is memory pressure:
if (stack->pool->free_stacks) {
fiber_pool_stack_free(&vacancy->stack);
}
#endif
}
static COROUTINE
fiber_entry(struct coroutine_context * from, struct coroutine_context * to)
{
rb_fiber_start();
}
// Initialize a fiber's coroutine's machine stack and vm stack.
static VALUE *
fiber_initialize_coroutine(rb_fiber_t *fiber, size_t * vm_stack_size)
{
struct fiber_pool * fiber_pool = fiber->stack.pool;
rb_execution_context_t *sec = &fiber->cont.saved_ec;
void * vm_stack = NULL;
VM_ASSERT(fiber_pool != NULL);
fiber->stack = fiber_pool_stack_acquire(fiber_pool);
vm_stack = fiber_pool_stack_alloca(&fiber->stack, fiber_pool->vm_stack_size);
*vm_stack_size = fiber_pool->vm_stack_size;
#ifdef COROUTINE_PRIVATE_STACK
coroutine_initialize(&fiber->context, fiber_entry, fiber_pool_stack_base(&fiber->stack), fiber->stack.available, sec->machine.stack_start);
// The stack for this execution context is still the main machine stack, so don't adjust it.
// If this is not managed correctly, you will fail in `rb_ec_stack_check`.
// We limit the machine stack usage to the fiber stack size.
if (sec->machine.stack_maxsize > fiber->stack.available) {
sec->machine.stack_maxsize = fiber->stack.available;
}
#else
coroutine_initialize(&fiber->context, fiber_entry, fiber_pool_stack_base(&fiber->stack), fiber->stack.available);
// The stack for this execution context is the one we allocated:
sec->machine.stack_start = fiber->stack.current;
sec->machine.stack_maxsize = fiber->stack.available;
#endif
return vm_stack;
}
// Release the stack from the fiber, it's execution context, and return it to the fiber pool.
static void
fiber_stack_release(rb_fiber_t * fiber)
{
rb_execution_context_t *ec = &fiber->cont.saved_ec;
if (DEBUG) fprintf(stderr, "fiber_stack_release: %p, stack.base=%p\n", (void*)fiber, fiber->stack.base);
// Return the stack back to the fiber pool if it wasn't already:
if (fiber->stack.base) {
fiber_pool_stack_release(&fiber->stack);
fiber->stack.base = NULL;
}
// The stack is no longer associated with this execution context:
rb_ec_clear_vm_stack(ec);
}
static const char *
fiber_status_name(enum fiber_status s)
{
switch (s) {
case FIBER_CREATED: return "created";
case FIBER_RESUMED: return "resumed";
case FIBER_SUSPENDED: return "suspended";
case FIBER_TERMINATED: return "terminated";
}
VM_UNREACHABLE(fiber_status_name);
return NULL;
}
static void
fiber_verify(const rb_fiber_t *fiber)
{
#if VM_CHECK_MODE > 0
VM_ASSERT(fiber->cont.saved_ec.fiber_ptr == fiber);
switch (fiber->status) {
case FIBER_RESUMED:
VM_ASSERT(fiber->cont.saved_ec.vm_stack != NULL);
break;
case FIBER_SUSPENDED:
VM_ASSERT(fiber->cont.saved_ec.vm_stack != NULL);
break;
case FIBER_CREATED:
case FIBER_TERMINATED:
/* TODO */
break;
default:
VM_UNREACHABLE(fiber_verify);
}
#endif
}
inline static void
fiber_status_set(rb_fiber_t *fiber, enum fiber_status s)
{
// if (DEBUG) fprintf(stderr, "fiber: %p, status: %s -> %s\n", (void *)fiber, fiber_status_name(fiber->status), fiber_status_name(s));
VM_ASSERT(!FIBER_TERMINATED_P(fiber));
VM_ASSERT(fiber->status != s);
fiber_verify(fiber);
fiber->status = s;
}
static inline void
ec_switch(rb_thread_t *th, rb_fiber_t *fiber)
{
rb_execution_context_t *ec = &fiber->cont.saved_ec;
rb_ractor_set_current_ec(th->ractor, th->ec = ec);
// ruby_current_execution_context_ptr = th->ec = ec;
/*
* timer-thread may set trap interrupt on previous th->ec at any time;
* ensure we do not delay (or lose) the trap interrupt handling.
*/
if (th->vm->ractor.main_thread == th &&
rb_signal_buff_size() > 0) {
RUBY_VM_SET_TRAP_INTERRUPT(ec);
}
VM_ASSERT(ec->fiber_ptr->cont.self == 0 || ec->vm_stack != NULL);
}
static rb_context_t *
cont_ptr(VALUE obj)
{
rb_context_t *cont;
TypedData_Get_Struct(obj, rb_context_t, &cont_data_type, cont);
return cont;
}
static rb_fiber_t *
fiber_ptr(VALUE obj)
{
rb_fiber_t *fiber;
TypedData_Get_Struct(obj, rb_fiber_t, &fiber_data_type, fiber);
if (!fiber) rb_raise(rb_eFiberError, "uninitialized fiber");
return fiber;
}
NOINLINE(static VALUE cont_capture(volatile int *volatile stat));
#define THREAD_MUST_BE_RUNNING(th) do { \
if (!(th)->ec->tag) rb_raise(rb_eThreadError, "not running thread"); \
} while (0)
rb_thread_t*
rb_fiber_threadptr(const rb_fiber_t *fiber)
{
return fiber->cont.saved_ec.thread_ptr;
}
static VALUE
cont_thread_value(const rb_context_t *cont)
{
return cont->saved_ec.thread_ptr->self;
}
static void
cont_compact(void *ptr)
{
rb_context_t *cont = ptr;
if (cont->self) {
cont->self = rb_gc_location(cont->self);
}
cont->value = rb_gc_location(cont->value);
rb_execution_context_update(&cont->saved_ec);
}
static void
cont_mark(void *ptr)
{
rb_context_t *cont = ptr;
RUBY_MARK_ENTER("cont");
if (cont->self) {
rb_gc_mark_movable(cont->self);
}
rb_gc_mark_movable(cont->value);
rb_execution_context_mark(&cont->saved_ec);
rb_gc_mark(cont_thread_value(cont));
if (cont->saved_vm_stack.ptr) {
#ifdef CAPTURE_JUST_VALID_VM_STACK
rb_gc_mark_locations(cont->saved_vm_stack.ptr,
cont->saved_vm_stack.ptr + cont->saved_vm_stack.slen + cont->saved_vm_stack.clen);
#else
rb_gc_mark_locations(cont->saved_vm_stack.ptr,
cont->saved_vm_stack.ptr, cont->saved_ec.stack_size);
#endif
}
if (cont->machine.stack) {
if (cont->type == CONTINUATION_CONTEXT) {
/* cont */
rb_gc_mark_locations(cont->machine.stack,
cont->machine.stack + cont->machine.stack_size);
}
else {
/* fiber */
const rb_fiber_t *fiber = (rb_fiber_t*)cont;
if (!FIBER_TERMINATED_P(fiber)) {
rb_gc_mark_locations(cont->machine.stack,
cont->machine.stack + cont->machine.stack_size);
}
}
}
RUBY_MARK_LEAVE("cont");
}
#if 0
static int
fiber_is_root_p(const rb_fiber_t *fiber)
{
return fiber == fiber->cont.saved_ec.thread_ptr->root_fiber;
}
#endif
static void
cont_free(void *ptr)
{
rb_context_t *cont = ptr;
RUBY_FREE_ENTER("cont");
if (cont->type == CONTINUATION_CONTEXT) {
ruby_xfree(cont->saved_ec.vm_stack);
ruby_xfree(cont->ensure_array);
RUBY_FREE_UNLESS_NULL(cont->machine.stack);
}
else {
rb_fiber_t *fiber = (rb_fiber_t*)cont;
coroutine_destroy(&fiber->context);
fiber_stack_release(fiber);
}
RUBY_FREE_UNLESS_NULL(cont->saved_vm_stack.ptr);
if (mjit_enabled) {
VM_ASSERT(cont->mjit_cont != NULL);
mjit_cont_free(cont->mjit_cont);
}
/* free rb_cont_t or rb_fiber_t */
ruby_xfree(ptr);
RUBY_FREE_LEAVE("cont");
}
static size_t
cont_memsize(const void *ptr)
{
const rb_context_t *cont = ptr;
size_t size = 0;
size = sizeof(*cont);
if (cont->saved_vm_stack.ptr) {
#ifdef CAPTURE_JUST_VALID_VM_STACK
size_t n = (cont->saved_vm_stack.slen + cont->saved_vm_stack.clen);
#else
size_t n = cont->saved_ec.vm_stack_size;
#endif
size += n * sizeof(*cont->saved_vm_stack.ptr);
}
if (cont->machine.stack) {
size += cont->machine.stack_size * sizeof(*cont->machine.stack);
}
return size;
}
void
rb_fiber_update_self(rb_fiber_t *fiber)
{
if (fiber->cont.self) {
fiber->cont.self = rb_gc_location(fiber->cont.self);
}
else {
rb_execution_context_update(&fiber->cont.saved_ec);
}
}
void
rb_fiber_mark_self(const rb_fiber_t *fiber)
{
if (fiber->cont.self) {
rb_gc_mark_movable(fiber->cont.self);
}
else {
rb_execution_context_mark(&fiber->cont.saved_ec);
}
}
static void
fiber_compact(void *ptr)
{
rb_fiber_t *fiber = ptr;
fiber->first_proc = rb_gc_location(fiber->first_proc);
if (fiber->prev) rb_fiber_update_self(fiber->prev);
cont_compact(&fiber->cont);
fiber_verify(fiber);
}
static void
fiber_mark(void *ptr)
{
rb_fiber_t *fiber = ptr;
RUBY_MARK_ENTER("cont");
fiber_verify(fiber);
rb_gc_mark_movable(fiber->first_proc);
if (fiber->prev) rb_fiber_mark_self(fiber->prev);
cont_mark(&fiber->cont);
RUBY_MARK_LEAVE("cont");
}
static void
fiber_free(void *ptr)
{
rb_fiber_t *fiber = ptr;
RUBY_FREE_ENTER("fiber");
//if (DEBUG) fprintf(stderr, "fiber_free: %p[%p]\n", fiber, fiber->stack.base);
if (fiber->cont.saved_ec.local_storage) {
rb_id_table_free(fiber->cont.saved_ec.local_storage);
}
cont_free(&fiber->cont);
RUBY_FREE_LEAVE("fiber");
}
static size_t
fiber_memsize(const void *ptr)
{
const rb_fiber_t *fiber = ptr;
size_t size = sizeof(*fiber);
const rb_execution_context_t *saved_ec = &fiber->cont.saved_ec;
const rb_thread_t *th = rb_ec_thread_ptr(saved_ec);
/*
* vm.c::thread_memsize already counts th->ec->local_storage
*/
if (saved_ec->local_storage && fiber != th->root_fiber) {
size += rb_id_table_memsize(saved_ec->local_storage);
}
size += cont_memsize(&fiber->cont);
return size;
}
VALUE
rb_obj_is_fiber(VALUE obj)
{
if (rb_typeddata_is_kind_of(obj, &fiber_data_type)) {
return Qtrue;
}
else {
return Qfalse;
}
}
static void
cont_save_machine_stack(rb_thread_t *th, rb_context_t *cont)
{
size_t size;
SET_MACHINE_STACK_END(&th->ec->machine.stack_end);
if (th->ec->machine.stack_start > th->ec->machine.stack_end) {
size = cont->machine.stack_size = th->ec->machine.stack_start - th->ec->machine.stack_end;
cont->machine.stack_src = th->ec->machine.stack_end;
}
else {
size = cont->machine.stack_size = th->ec->machine.stack_end - th->ec->machine.stack_start;
cont->machine.stack_src = th->ec->machine.stack_start;
}
if (cont->machine.stack) {
REALLOC_N(cont->machine.stack, VALUE, size);
}
else {
cont->machine.stack = ALLOC_N(VALUE, size);
}
FLUSH_REGISTER_WINDOWS;
MEMCPY(cont->machine.stack, cont->machine.stack_src, VALUE, size);
}
static const rb_data_type_t cont_data_type = {
"continuation",
{cont_mark, cont_free, cont_memsize, cont_compact},
0, 0, RUBY_TYPED_FREE_IMMEDIATELY
};
static inline void
cont_save_thread(rb_context_t *cont, rb_thread_t *th)
{
rb_execution_context_t *sec = &cont->saved_ec;
VM_ASSERT(th->status == THREAD_RUNNABLE);
/* save thread context */
*sec = *th->ec;
/* saved_ec->machine.stack_end should be NULL */
/* because it may happen GC afterward */
sec->machine.stack_end = NULL;
}
static void
cont_init_mjit_cont(rb_context_t *cont)
{
VM_ASSERT(cont->mjit_cont == NULL);
if (mjit_enabled) {
cont->mjit_cont = mjit_cont_new(&(cont->saved_ec));
}
}
static void
cont_init(rb_context_t *cont, rb_thread_t *th)
{
/* save thread context */
cont_save_thread(cont, th);
cont->saved_ec.thread_ptr = th;
cont->saved_ec.local_storage = NULL;
cont->saved_ec.local_storage_recursive_hash = Qnil;
cont->saved_ec.local_storage_recursive_hash_for_trace = Qnil;
cont_init_mjit_cont(cont);
}
static rb_context_t *
cont_new(VALUE klass)
{
rb_context_t *cont;
volatile VALUE contval;
rb_thread_t *th = GET_THREAD();
THREAD_MUST_BE_RUNNING(th);
contval = TypedData_Make_Struct(klass, rb_context_t, &cont_data_type, cont);
cont->self = contval;
cont_init(cont, th);
return cont;
}
VALUE rb_fiberptr_self(struct rb_fiber_struct *fiber)
{
return fiber->cont.self;
}
// This is used for root_fiber because other fibers call cont_init_mjit_cont through cont_new.
void
rb_fiber_init_mjit_cont(struct rb_fiber_struct *fiber)
{
cont_init_mjit_cont(&fiber->cont);
}
#if 0
void
show_vm_stack(const rb_execution_context_t *ec)
{
VALUE *p = ec->vm_stack;
while (p < ec->cfp->sp) {
fprintf(stderr, "%3d ", (int)(p - ec->vm_stack));
rb_obj_info_dump(*p);
p++;
}
}
void
show_vm_pcs(const rb_control_frame_t *cfp,
const rb_control_frame_t *end_of_cfp)
{
int i=0;
while (cfp != end_of_cfp) {
int pc = 0;
if (cfp->iseq) {
pc = cfp->pc - cfp->iseq->body->iseq_encoded;
}
fprintf(stderr, "%2d pc: %d\n", i++, pc);
cfp = RUBY_VM_PREVIOUS_CONTROL_FRAME(cfp);
}
}
#endif
COMPILER_WARNING_PUSH
#ifdef __clang__
COMPILER_WARNING_IGNORED(-Wduplicate-decl-specifier)
#endif
static VALUE
cont_capture(volatile int *volatile stat)
{
rb_context_t *volatile cont;
rb_thread_t *th = GET_THREAD();
volatile VALUE contval;
const rb_execution_context_t *ec = th->ec;
THREAD_MUST_BE_RUNNING(th);
rb_vm_stack_to_heap(th->ec);
cont = cont_new(rb_cContinuation);
contval = cont->self;
#ifdef CAPTURE_JUST_VALID_VM_STACK
cont->saved_vm_stack.slen = ec->cfp->sp - ec->vm_stack;
cont->saved_vm_stack.clen = ec->vm_stack + ec->vm_stack_size - (VALUE*)ec->cfp;
cont->saved_vm_stack.ptr = ALLOC_N(VALUE, cont->saved_vm_stack.slen + cont->saved_vm_stack.clen);
MEMCPY(cont->saved_vm_stack.ptr,
ec->vm_stack,
VALUE, cont->saved_vm_stack.slen);
MEMCPY(cont->saved_vm_stack.ptr + cont->saved_vm_stack.slen,
(VALUE*)ec->cfp,
VALUE,
cont->saved_vm_stack.clen);
#else
cont->saved_vm_stack.ptr = ALLOC_N(VALUE, ec->vm_stack_size);
MEMCPY(cont->saved_vm_stack.ptr, ec->vm_stack, VALUE, ec->vm_stack_size);
#endif
// At this point, `cfp` is valid but `vm_stack` should be cleared:
rb_ec_set_vm_stack(&cont->saved_ec, NULL, 0);
VM_ASSERT(cont->saved_ec.cfp != NULL);
cont_save_machine_stack(th, cont);
/* backup ensure_list to array for search in another context */
{
rb_ensure_list_t *p;
int size = 0;
rb_ensure_entry_t *entry;
for (p=th->ec->ensure_list; p; p=p->next)
size++;
entry = cont->ensure_array = ALLOC_N(rb_ensure_entry_t,size+1);
for (p=th->ec->ensure_list; p; p=p->next) {
if (!p->entry.marker)
p->entry.marker = rb_ary_tmp_new(0); /* dummy object */
*entry++ = p->entry;
}
entry->marker = 0;
}
if (ruby_setjmp(cont->jmpbuf)) {
VALUE value;
VAR_INITIALIZED(cont);
value = cont->value;
if (cont->argc == -1) rb_exc_raise(value);
cont->value = Qnil;
*stat = 1;
return value;
}
else {
*stat = 0;
return contval;
}
}
COMPILER_WARNING_POP
static inline void
fiber_restore_thread(rb_thread_t *th, rb_fiber_t *fiber)
{
ec_switch(th, fiber);
VM_ASSERT(th->ec->fiber_ptr == fiber);
}
static inline void
cont_restore_thread(rb_context_t *cont)
{
rb_thread_t *th = GET_THREAD();
/* restore thread context */
if (cont->type == CONTINUATION_CONTEXT) {
/* continuation */
rb_execution_context_t *sec = &cont->saved_ec;
rb_fiber_t *fiber = NULL;
if (sec->fiber_ptr != NULL) {
fiber = sec->fiber_ptr;
}
else if (th->root_fiber) {
fiber = th->root_fiber;
}
if (fiber && th->ec != &fiber->cont.saved_ec) {
ec_switch(th, fiber);
}
if (th->ec->trace_arg != sec->trace_arg) {
rb_raise(rb_eRuntimeError, "can't call across trace_func");
}
/* copy vm stack */
#ifdef CAPTURE_JUST_VALID_VM_STACK
MEMCPY(th->ec->vm_stack,
cont->saved_vm_stack.ptr,
VALUE, cont->saved_vm_stack.slen);
MEMCPY(th->ec->vm_stack + th->ec->vm_stack_size - cont->saved_vm_stack.clen,
cont->saved_vm_stack.ptr + cont->saved_vm_stack.slen,
VALUE, cont->saved_vm_stack.clen);
#else
MEMCPY(th->ec->vm_stack, cont->saved_vm_stack.ptr, VALUE, sec->vm_stack_size);
#endif
/* other members of ec */
th->ec->cfp = sec->cfp;
th->ec->raised_flag = sec->raised_flag;
th->ec->tag = sec->tag;
th->ec->protect_tag = sec->protect_tag;
th->ec->root_lep = sec->root_lep;
th->ec->root_svar = sec->root_svar;
th->ec->ensure_list = sec->ensure_list;
th->ec->errinfo = sec->errinfo;
VM_ASSERT(th->ec->vm_stack != NULL);
}
else {
/* fiber */
fiber_restore_thread(th, (rb_fiber_t*)cont);
}
}
NOINLINE(static void fiber_setcontext(rb_fiber_t *new_fiber, rb_fiber_t *old_fiber));
static void
fiber_setcontext(rb_fiber_t *new_fiber, rb_fiber_t *old_fiber)
{
rb_thread_t *th = GET_THREAD();
/* save old_fiber's machine stack - to ensure efficient garbage collection */
if (!FIBER_TERMINATED_P(old_fiber)) {
STACK_GROW_DIR_DETECTION;
SET_MACHINE_STACK_END(&th->ec->machine.stack_end);
if (STACK_DIR_UPPER(0, 1)) {
old_fiber->cont.machine.stack_size = th->ec->machine.stack_start - th->ec->machine.stack_end;
old_fiber->cont.machine.stack = th->ec->machine.stack_end;
}
else {
old_fiber->cont.machine.stack_size = th->ec->machine.stack_end - th->ec->machine.stack_start;
old_fiber->cont.machine.stack = th->ec->machine.stack_start;
}
}
/* exchange machine_stack_start between old_fiber and new_fiber */
old_fiber->cont.saved_ec.machine.stack_start = th->ec->machine.stack_start;
/* old_fiber->machine.stack_end should be NULL */
old_fiber->cont.saved_ec.machine.stack_end = NULL;
/* restore thread context */
fiber_restore_thread(th, new_fiber);
// if (DEBUG) fprintf(stderr, "fiber_setcontext: %p[%p] -> %p[%p]\n", old_fiber, old_fiber->stack.base, new_fiber, new_fiber->stack.base);
/* swap machine context */
coroutine_transfer(&old_fiber->context, &new_fiber->context);
// It's possible to get here, and new_fiber is already freed.
// if (DEBUG) fprintf(stderr, "fiber_setcontext: %p[%p] <- %p[%p]\n", old_fiber, old_fiber->stack.base, new_fiber, new_fiber->stack.base);
}
NOINLINE(NORETURN(static void cont_restore_1(rb_context_t *)));
static void
cont_restore_1(rb_context_t *cont)
{
cont_restore_thread(cont);
/* restore machine stack */
#ifdef _M_AMD64
{
/* workaround for x64 SEH */
jmp_buf buf;
setjmp(buf);
_JUMP_BUFFER *bp = (void*)&cont->jmpbuf;
bp->Frame = ((_JUMP_BUFFER*)((void*)&buf))->Frame;
}
#endif
if (cont->machine.stack_src) {
FLUSH_REGISTER_WINDOWS;
MEMCPY(cont->machine.stack_src, cont->machine.stack,
VALUE, cont->machine.stack_size);
}
ruby_longjmp(cont->jmpbuf, 1);
}
NORETURN(NOINLINE(static void cont_restore_0(rb_context_t *, VALUE *)));
static void
cont_restore_0(rb_context_t *cont, VALUE *addr_in_prev_frame)
{
if (cont->machine.stack_src) {
#ifdef HAVE_ALLOCA
#define STACK_PAD_SIZE 1
#else
#define STACK_PAD_SIZE 1024
#endif
VALUE space[STACK_PAD_SIZE];
#if !STACK_GROW_DIRECTION
if (addr_in_prev_frame > &space[0]) {
/* Stack grows downward */
#endif
#if STACK_GROW_DIRECTION <= 0
volatile VALUE *const end = cont->machine.stack_src;
if (&space[0] > end) {
# ifdef HAVE_ALLOCA
volatile VALUE *sp = ALLOCA_N(VALUE, &space[0] - end);
space[0] = *sp;
# else
cont_restore_0(cont, &space[0]);
# endif
}
#endif
#if !STACK_GROW_DIRECTION
}
else {
/* Stack grows upward */
#endif
#if STACK_GROW_DIRECTION >= 0
volatile VALUE *const end = cont->machine.stack_src + cont->machine.stack_size;
if (&space[STACK_PAD_SIZE] < end) {
# ifdef HAVE_ALLOCA
volatile VALUE *sp = ALLOCA_N(VALUE, end - &space[STACK_PAD_SIZE]);
space[0] = *sp;
# else
cont_restore_0(cont, &space[STACK_PAD_SIZE-1]);
# endif
}
#endif
#if !STACK_GROW_DIRECTION
}
#endif
}
cont_restore_1(cont);
}
/*
* Document-class: Continuation
*
* Continuation objects are generated by Kernel#callcc,
* after having +require+d <i>continuation</i>. 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 <code>setjmp/longjmp</code> (although they contain
* more state, so you might consider them closer to threads).
*
* For instance:
*
* require "continuation"
* arr = [ "Freddie", "Herbie", "Ron", "Max", "Ringo" ]
* callcc{|cc| $cc = cc}
* puts(message = arr.shift)
* $cc.call unless message =~ /Max/
*
* <em>produces:</em>
*
* Freddie
* Herbie
* Ron
* Max
*
* Also you can call callcc in other methods:
*
* require "continuation"
*
* def g
* arr = [ "Freddie", "Herbie", "Ron", "Max", "Ringo" ]
* cc = callcc { |cc| cc }
* puts arr.shift
* return cc, arr.size
* end
*
* def f
* c, size = g
* c.call(c) if size > 1
* end
*
* f
*
* This (somewhat contrived) example allows the inner loop to abandon
* processing early:
*
* require "continuation"
* callcc {|cont|
* for i in 0..4
* print "#{i}: "
* for j in i*5...(i+1)*5
* cont.call() if j == 17
* printf "%3d", j
* end
* end
* }
* puts
*
* <em>produces:</em>
*
* 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. You need to <code>require
* 'continuation'</code> before using this method. Performing a
* <em>cont</em><code>.call</code> 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 <em>cont</em><code>.call</code>. 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, const VALUE *argv)
{
switch (argc) {
case -1:
return argv[0];
case 0:
return Qnil;
case 1:
return argv[0];
default:
return rb_ary_new4(argc, argv);
}
}
typedef VALUE e_proc(VALUE);
/* CAUTION!! : Currently, error in rollback_func is not supported */
/* same as rb_protect if set rollback_func to NULL */
void
ruby_register_rollback_func_for_ensure(e_proc *ensure_func, e_proc *rollback_func)
{
st_table **table_p = &GET_VM()->ensure_rollback_table;
if (UNLIKELY(*table_p == NULL)) {
*table_p = st_init_numtable();
}
st_insert(*table_p, (st_data_t)ensure_func, (st_data_t)rollback_func);
}
static inline e_proc *
lookup_rollback_func(e_proc *ensure_func)
{
st_table *table = GET_VM()->ensure_rollback_table;
st_data_t val;
if (table && st_lookup(table, (st_data_t)ensure_func, &val))
return (e_proc *) val;
return (e_proc *) Qundef;
}
static inline void
rollback_ensure_stack(VALUE self,rb_ensure_list_t *current,rb_ensure_entry_t *target)
{
rb_ensure_list_t *p;
rb_ensure_entry_t *entry;
size_t i, j;
size_t cur_size;
size_t target_size;
size_t base_point;
e_proc *func;
cur_size = 0;
for (p=current; p; p=p->next)
cur_size++;
target_size = 0;
for (entry=target; entry->marker; entry++)
target_size++;
/* search common stack point */
p = current;
base_point = cur_size;
while (base_point) {
if (target_size >= base_point &&
p->entry.marker == target[target_size - base_point].marker)
break;
base_point --;
p = p->next;
}
/* rollback function check */
for (i=0; i < target_size - base_point; i++) {
if (!lookup_rollback_func(target[i].e_proc)) {
rb_raise(rb_eRuntimeError, "continuation called from out of critical rb_ensure scope");
}
}
/* pop ensure stack */
while (cur_size > base_point) {
/* escape from ensure block */
(*current->entry.e_proc)(current->entry.data2);
current = current->next;
cur_size--;
}
/* push ensure stack */
for (j = 0; j < i; j++) {
func = lookup_rollback_func(target[i - j - 1].e_proc);
if ((VALUE)func != Qundef) {
(*func)(target[i - j - 1].data2);
}
}
}
NORETURN(static VALUE rb_cont_call(int argc, VALUE *argv, VALUE contval));
/*
* 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 <i>args</i> 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 = cont_ptr(contval);
rb_thread_t *th = GET_THREAD();
if (cont_thread_value(cont) != th->self) {
rb_raise(rb_eRuntimeError, "continuation called across threads");
}
if (cont->saved_ec.protect_tag != th->ec->protect_tag) {
rb_raise(rb_eRuntimeError, "continuation called across stack rewinding barrier");
}
if (cont->saved_ec.fiber_ptr) {
if (th->ec->fiber_ptr != cont->saved_ec.fiber_ptr) {
rb_raise(rb_eRuntimeError, "continuation called across fiber");
}
}
rollback_ensure_stack(contval, th->ec->ensure_list, cont->ensure_array);
cont->argc = argc;
cont->value = make_passing_arg(argc, argv);
cont_restore_0(cont, &contval);
UNREACHABLE_RETURN(Qnil);
}
/*********/
/* fiber */
/*********/
/*
* Document-class: Fiber
*
* Fibers are primitives for implementing light weight cooperative
* concurrency in Ruby. Basically they are a means of creating code blocks
* that can be paused and resumed, much like threads. The main difference
* is that they are never preempted and that the scheduling must be done by
* the programmer and not the VM.
*
* As opposed to other stackless light weight concurrency models, each fiber
* comes with a stack. This enables the fiber to be paused from deeply
* nested function calls within the fiber block. See the ruby(1)
* manpage to configure the size of the fiber stack(s).
*
* When a fiber is created it will not run automatically. Rather it must
* be explicitly asked to run using the Fiber#resume method.
* The code running inside the fiber can give up control by calling
* Fiber.yield in which case it yields control back to caller (the
* caller of the Fiber#resume).
*
* Upon yielding or termination the Fiber returns the value of the last
* executed expression
*
* For instance:
*
* fiber = Fiber.new do
* Fiber.yield 1
* 2
* end
*
* puts fiber.resume
* puts fiber.resume
* puts fiber.resume
*
* <em>produces</em>
*
* 1
* 2
* FiberError: dead fiber called
*
* The Fiber#resume method accepts an arbitrary number of parameters,
* if it is the first call to #resume then they will be passed as
* block arguments. Otherwise they will be the return value of the
* call to Fiber.yield
*
* Example:
*
* fiber = Fiber.new do |first|
* second = Fiber.yield first + 2
* end
*
* puts fiber.resume 10
* puts fiber.resume 1_000_000
* puts fiber.resume "The fiber will be dead before I can cause trouble"
*
* <em>produces</em>
*
* 12
* 1000000
* FiberError: dead fiber called
*
* == Non-blocking Fibers
*
* The concept of <em>non-blocking fiber</em> was introduced in Ruby 3.0.
* A non-blocking fiber, when reaching a operation that would normally block
* the fiber (like <code>sleep</code>, or wait for another process or I/O)
# will yield control to other fibers and allow the <em>scheduler</em> to
# handle blocking and waking up (resuming) this fiber when it can proceed.
*
* For a Fiber to behave as non-blocking, it need to be created in Fiber.new with
* <tt>blocking: false</tt> (which is the default), and Fiber.scheduler
* should be set with Fiber.set_scheduler. If Fiber.scheduler is not set in
* the current thread, blocking and non-blocking fibers' behavior is identical.
*
* Ruby doesn't provide a scheduler class: it is expected to be implemented by
* the user and correspond to Fiber::SchedulerInterface.
*
* There is also Fiber.schedule method, which is expected to immediately perform
* the given block in a non-blocking manner. Its actual implementation is up to
* the scheduler.
*
*/
static const rb_data_type_t fiber_data_type = {
"fiber",
{fiber_mark, fiber_free, fiber_memsize, fiber_compact,},
0, 0, RUBY_TYPED_FREE_IMMEDIATELY
};
static VALUE
fiber_alloc(VALUE klass)
{
return TypedData_Wrap_Struct(klass, &fiber_data_type, 0);
}
static rb_fiber_t*
fiber_t_alloc(VALUE fiber_value, unsigned int blocking)
{
rb_fiber_t *fiber;
rb_thread_t *th = GET_THREAD();
if (DATA_PTR(fiber_value) != 0) {
rb_raise(rb_eRuntimeError, "cannot initialize twice");
}
THREAD_MUST_BE_RUNNING(th);
fiber = ZALLOC(rb_fiber_t);
fiber->cont.self = fiber_value;
fiber->cont.type = FIBER_CONTEXT;
fiber->blocking = blocking;
cont_init(&fiber->cont, th);
fiber->cont.saved_ec.fiber_ptr = fiber;
rb_ec_clear_vm_stack(&fiber->cont.saved_ec);
fiber->prev = NULL;
/* fiber->status == 0 == CREATED
* So that we don't need to set status: fiber_status_set(fiber, FIBER_CREATED); */
VM_ASSERT(FIBER_CREATED_P(fiber));
DATA_PTR(fiber_value) = fiber;
return fiber;
}
static VALUE
fiber_initialize(VALUE self, VALUE proc, struct fiber_pool * fiber_pool, unsigned int blocking)
{
rb_fiber_t *fiber = fiber_t_alloc(self, blocking);
fiber->first_proc = proc;
fiber->stack.base = NULL;
fiber->stack.pool = fiber_pool;
return self;
}
static void
fiber_prepare_stack(rb_fiber_t *fiber)
{
rb_context_t *cont = &fiber->cont;
rb_execution_context_t *sec = &cont->saved_ec;
size_t vm_stack_size = 0;
VALUE *vm_stack = fiber_initialize_coroutine(fiber, &vm_stack_size);
/* initialize cont */
cont->saved_vm_stack.ptr = NULL;
rb_ec_initialize_vm_stack(sec, vm_stack, vm_stack_size / sizeof(VALUE));
sec->tag = NULL;
sec->local_storage = NULL;
sec->local_storage_recursive_hash = Qnil;
sec->local_storage_recursive_hash_for_trace = Qnil;
}
static struct fiber_pool *
rb_fiber_pool_default(VALUE pool)
{
return &shared_fiber_pool;
}
/* :nodoc: */
static VALUE
rb_fiber_initialize_kw(int argc, VALUE* argv, VALUE self, int kw_splat)
{
VALUE pool = Qnil;
VALUE blocking = Qfalse;
if (kw_splat != RB_NO_KEYWORDS) {
VALUE options = Qnil;
VALUE arguments[2] = {Qundef};
argc = rb_scan_args_kw(kw_splat, argc, argv, ":", &options);
rb_get_kwargs(options, fiber_initialize_keywords, 0, 2, arguments);
if (arguments[0] != Qundef) {
blocking = arguments[0];
}
if (arguments[1] != Qundef) {
pool = arguments[1];
}
}
return fiber_initialize(self, rb_block_proc(), rb_fiber_pool_default(pool), RTEST(blocking));
}
/*
* call-seq:
* Fiber.new(blocking: false) { |*args| ... } -> fiber
*
* Creates new Fiber. Initially, the fiber is not running and can be resumed with
* #resume. Arguments to the first #resume call will be passed to the block:
*
* f = Fiber.new do |initial|
* current = initial
* loop do
* puts "current: #{current.inspect}"
* current = Fiber.yield
* end
* end
* f.resume(100) # prints: current: 100
* f.resume(1, 2, 3) # prints: current: [1, 2, 3]
* f.resume # prints: current: nil
* # ... and so on ...
*
* If <tt>blocking: false</tt> is passed to <tt>Fiber.new</tt>, _and_ current thread
* has a Fiber.scheduler defined, the Fiber becomes non-blocking (see "Non-blocking
* Fibers" section in class docs).
*/
static VALUE
rb_fiber_initialize(int argc, VALUE* argv, VALUE self)
{
return rb_fiber_initialize_kw(argc, argv, self, rb_keyword_given_p());
}
VALUE
rb_fiber_new(rb_block_call_func_t func, VALUE obj)
{
return fiber_initialize(fiber_alloc(rb_cFiber), rb_proc_new(func, obj), rb_fiber_pool_default(Qnil), 1);
}
static VALUE
rb_f_fiber_kw(int argc, VALUE* argv, int kw_splat)
{
rb_thread_t * th = GET_THREAD();
VALUE scheduler = th->scheduler;
VALUE fiber = Qnil;
if (scheduler != Qnil) {
fiber = rb_funcall_passing_block_kw(scheduler, rb_intern("fiber"), argc, argv, kw_splat);
}
else {
rb_raise(rb_eRuntimeError, "No scheduler is available!");
}
return fiber;
}
/*
* call-seq:
* Fiber.schedule { |*args| ... } -> fiber
*
* The method is <em>expected</em> to immediately run the provided block of code in a
* separate non-blocking fiber.
*
* puts "Go to sleep!"
*
* Fiber.set_scheduler(MyScheduler.new)
*
* Fiber.schedule do
* puts "Going to sleep"
* sleep(1)
* puts "I slept well"
* end
*
* puts "Wakey-wakey, sleepyhead"
*
* Assuming MyScheduler is properly implemented, this program will produce:
*
* Go to sleep!
* Going to sleep
* Wakey-wakey, sleepyhead
* ...1 sec pause here...
* I slept well
*
* ...e.g. on the first blocking operation inside the Fiber (<tt>sleep(1)</tt>),
* the control is yielded to the outside code (main fiber), and <em>at the end
* of that execution</em>, the scheduler takes care of properly resuming all the
* blocked fibers.
*
* Note that the behavior described above is how the method is <em>expected</em>
* to behave, actual behavior is up to the current scheduler's implementation of
* Fiber::SchedulerInterface#fiber method. Ruby doesn't enforce this method to
* behave in any particular way.
*
* If the scheduler is not set, the method raises
* <tt>RuntimeError (No scheduler is available!)</tt>.
*
*/
static VALUE
rb_f_fiber(int argc, VALUE *argv, VALUE obj)
{
return rb_f_fiber_kw(argc, argv, rb_keyword_given_p());
}
/*
* call-seq:
* Fiber.scheduler -> obj or nil
*
* Returns the Fiber scheduler, that was last set for the current thread with Fiber.set_scheduler.
* Returns +nil+ if no scheduler is set (which is the default), and non-blocking fibers'
# behavior is the same as blocking.
* (see "Non-blocking fibers" section in class docs for details about the scheduler concept).
*
*/
static VALUE
rb_fiber_scheduler(VALUE klass)
{
return rb_scheduler_get();
}
/*
* call-seq:
* Fiber.set_scheduler(scheduler) -> scheduler
*
* Sets the Fiber scheduler for the current thread. If the scheduler is set, non-blocking
* fibers (created by Fiber.new with <tt>blocking: false</tt>, or by Fiber.schedule)
* call that scheduler's hook methods on potentially blocking operations, and the current
* thread will call scheduler's +close+ method on finalization (allowing the scheduler to
* properly manage all non-finished fibers).
*
* +scheduler+ can be an object of any class corresponding to Fiber::SchedulerInterface. Its
* implementation is up to the user.
*
* See also the "Non-blocking fibers" section in class docs.
*
*/
static VALUE
rb_fiber_set_scheduler(VALUE klass, VALUE scheduler)
{
// if (rb_scheduler_get() != Qnil) {
// rb_raise(rb_eFiberError, "Scheduler is already defined!");
// }
return rb_scheduler_set(scheduler);
}
static void rb_fiber_terminate(rb_fiber_t *fiber, int need_interrupt);
void
rb_fiber_start(void)
{
rb_thread_t * volatile th = GET_THREAD();
rb_fiber_t *fiber = th->ec->fiber_ptr;
rb_proc_t *proc;
enum ruby_tag_type state;
int need_interrupt = TRUE;
VM_ASSERT(th->ec == GET_EC());
VM_ASSERT(FIBER_RESUMED_P(fiber));
if (fiber->blocking) {
th->blocking += 1;
}
EC_PUSH_TAG(th->ec);
if ((state = EC_EXEC_TAG()) == TAG_NONE) {
rb_context_t *cont = &VAR_FROM_MEMORY(fiber)->cont;
int argc;
const VALUE *argv, args = cont->value;
GetProcPtr(fiber->first_proc, proc);
argv = (argc = cont->argc) > 1 ? RARRAY_CONST_PTR(args) : &args;
cont->value = Qnil;
th->ec->errinfo = Qnil;
th->ec->root_lep = rb_vm_proc_local_ep(fiber->first_proc);
th->ec->root_svar = Qfalse;
EXEC_EVENT_HOOK(th->ec, RUBY_EVENT_FIBER_SWITCH, th->self, 0, 0, 0, Qnil);
cont->value = rb_vm_invoke_proc(th->ec, proc, argc, argv, cont->kw_splat, VM_BLOCK_HANDLER_NONE);
}
EC_POP_TAG();
if (state) {
VALUE err = th->ec->errinfo;
VM_ASSERT(FIBER_RESUMED_P(fiber));
if (state == TAG_RAISE || state == TAG_FATAL) {
rb_threadptr_pending_interrupt_enque(th, err);
}
else {
err = rb_vm_make_jump_tag_but_local_jump(state, err);
if (!NIL_P(err)) {
rb_threadptr_pending_interrupt_enque(th, err);
}
}
need_interrupt = TRUE;
}
rb_fiber_terminate(fiber, need_interrupt);
VM_UNREACHABLE(rb_fiber_start);
}
static rb_fiber_t *
root_fiber_alloc(rb_thread_t *th)
{
VALUE fiber_value = fiber_alloc(rb_cFiber);
rb_fiber_t *fiber = th->ec->fiber_ptr;
VM_ASSERT(DATA_PTR(fiber_value) == NULL);
VM_ASSERT(fiber->cont.type == FIBER_CONTEXT);
VM_ASSERT(fiber->status == FIBER_RESUMED);
th->root_fiber = fiber;
DATA_PTR(fiber_value) = fiber;
fiber->cont.self = fiber_value;
#ifdef COROUTINE_PRIVATE_STACK
fiber->stack = fiber_pool_stack_acquire(&shared_fiber_pool);
coroutine_initialize_main(&fiber->context, fiber_pool_stack_base(&fiber->stack), fiber->stack.available, th->ec->machine.stack_start);
#else
coroutine_initialize_main(&fiber->context);
#endif
return fiber;
}
void
rb_threadptr_root_fiber_setup(rb_thread_t *th)
{
rb_fiber_t *fiber = ruby_mimmalloc(sizeof(rb_fiber_t));
if (!fiber) {
rb_bug("%s", strerror(errno)); /* ... is it possible to call rb_bug here? */
}
MEMZERO(fiber, rb_fiber_t, 1);
fiber->cont.type = FIBER_CONTEXT;
fiber->cont.saved_ec.fiber_ptr = fiber;
fiber->cont.saved_ec.thread_ptr = th;
fiber->blocking = 1;
fiber_status_set(fiber, FIBER_RESUMED); /* skip CREATED */
th->ec = &fiber->cont.saved_ec;
// This skips mjit_cont_new for the initial thread because mjit_enabled is always false
// at this point. mjit_init calls rb_fiber_init_mjit_cont again for this root_fiber.
rb_fiber_init_mjit_cont(fiber);
}
void
rb_threadptr_root_fiber_release(rb_thread_t *th)
{
if (th->root_fiber) {
/* ignore. A root fiber object will free th->ec */
}
else {
rb_execution_context_t *ec = GET_EC();
VM_ASSERT(th->ec->fiber_ptr->cont.type == FIBER_CONTEXT);
VM_ASSERT(th->ec->fiber_ptr->cont.self == 0);
if (th->ec == ec) {
rb_ractor_set_current_ec(th->ractor, NULL);
}
fiber_free(th->ec->fiber_ptr);
th->ec = NULL;
}
}
void
rb_threadptr_root_fiber_terminate(rb_thread_t *th)
{
rb_fiber_t *fiber = th->ec->fiber_ptr;
fiber->status = FIBER_TERMINATED;
// The vm_stack is `alloca`ed on the thread stack, so it's gone too:
rb_ec_clear_vm_stack(th->ec);
}
static inline rb_fiber_t*
fiber_current(void)
{
rb_execution_context_t *ec = GET_EC();
if (ec->fiber_ptr->cont.self == 0) {
root_fiber_alloc(rb_ec_thread_ptr(ec));
}
return ec->fiber_ptr;
}
static inline rb_fiber_t*
return_fiber(bool terminate)
{
rb_fiber_t *fiber = fiber_current();
rb_fiber_t *prev = fiber->prev;
if (prev) {
fiber->prev = NULL;
prev->resuming_fiber = Qnil;
return prev;
}
else {
if (!terminate) {
rb_raise(rb_eFiberError, "attempt to yield on a not resumed fiber");
}
rb_thread_t *th = GET_THREAD();
rb_fiber_t *root_fiber = th->root_fiber;
VM_ASSERT(root_fiber != NULL);
// search resuming fiber
for (fiber = root_fiber;
RTEST(fiber->resuming_fiber);
fiber = fiber_ptr(fiber->resuming_fiber)) {
}
return fiber;
}
}
VALUE
rb_fiber_current(void)
{
return fiber_current()->cont.self;
}
// Prepare to execute next_fiber on the given thread.
static inline VALUE
fiber_store(rb_fiber_t *next_fiber, rb_thread_t *th)
{
rb_fiber_t *fiber;
if (th->ec->fiber_ptr != NULL) {
fiber = th->ec->fiber_ptr;
}
else {
/* create root fiber */
fiber = root_fiber_alloc(th);
}
if (FIBER_CREATED_P(next_fiber)) {
fiber_prepare_stack(next_fiber);
}
VM_ASSERT(FIBER_RESUMED_P(fiber) || FIBER_TERMINATED_P(fiber));
VM_ASSERT(FIBER_RUNNABLE_P(next_fiber));
if (FIBER_RESUMED_P(fiber)) fiber_status_set(fiber, FIBER_SUSPENDED);
fiber_status_set(next_fiber, FIBER_RESUMED);
fiber_setcontext(next_fiber, fiber);
fiber = th->ec->fiber_ptr;
/* Raise an exception if that was the result of executing the fiber */
if (fiber->cont.argc == -1) rb_exc_raise(fiber->cont.value);
return fiber->cont.value;
}
static inline VALUE
fiber_switch(rb_fiber_t *fiber, int argc, const VALUE *argv, int kw_splat, VALUE resuming_fiber, bool yielding)
{
VALUE value;
rb_context_t *cont = &fiber->cont;
rb_thread_t *th = GET_THREAD();
/* make sure the root_fiber object is available */
if (th->root_fiber == NULL) root_fiber_alloc(th);
if (th->ec->fiber_ptr == fiber) {
/* ignore fiber context switch
* because destination fiber is the same as current fiber
*/
return make_passing_arg(argc, argv);
}
if (cont_thread_value(cont) != th->self) {
rb_raise(rb_eFiberError, "fiber called across threads");
}
else if (cont->saved_ec.protect_tag != th->ec->protect_tag) {
rb_raise(rb_eFiberError, "fiber called across stack rewinding barrier");
}
else if (FIBER_TERMINATED_P(fiber)) {
value = rb_exc_new2(rb_eFiberError, "dead fiber called");
if (!FIBER_TERMINATED_P(th->ec->fiber_ptr)) {
rb_exc_raise(value);
VM_UNREACHABLE(fiber_switch);
}
else {
/* th->ec->fiber_ptr is also dead => switch to root fiber */
/* (this means we're being called from rb_fiber_terminate, */
/* and the terminated fiber's return_fiber() is already dead) */
VM_ASSERT(FIBER_SUSPENDED_P(th->root_fiber));
cont = &th->root_fiber->cont;
cont->argc = -1;
cont->value = value;
fiber_setcontext(th->root_fiber, th->ec->fiber_ptr);
VM_UNREACHABLE(fiber_switch);
}
}
VM_ASSERT(FIBER_RUNNABLE_P(fiber));
rb_fiber_t *current_fiber = fiber_current();
VM_ASSERT(!RTEST(current_fiber->resuming_fiber));
if (RTEST(resuming_fiber)) {
current_fiber->resuming_fiber = resuming_fiber;
fiber->prev = fiber_current();
fiber->yielding = 0;
}
VM_ASSERT(!current_fiber->yielding);
if (yielding) {
current_fiber->yielding = 1;
}
if (current_fiber->blocking) {
th->blocking -= 1;
}
cont->argc = argc;
cont->kw_splat = kw_splat;
cont->value = make_passing_arg(argc, argv);
value = fiber_store(fiber, th);
if (RTEST(resuming_fiber) && FIBER_TERMINATED_P(fiber)) {
fiber_stack_release(fiber);
}
if (fiber_current()->blocking) {
th->blocking += 1;
}
RUBY_VM_CHECK_INTS(th->ec);
EXEC_EVENT_HOOK(th->ec, RUBY_EVENT_FIBER_SWITCH, th->self, 0, 0, 0, Qnil);
return value;
}
VALUE
rb_fiber_transfer(VALUE fiber_value, int argc, const VALUE *argv)
{
return fiber_switch(fiber_ptr(fiber_value), argc, argv, RB_NO_KEYWORDS, Qfalse, false);
}
/*
* call-seq:
* fiber.blocking? -> true or false
*
* Returns +true+ if +fiber+ is blocking and +false+ otherwise.
* Fiber is non-blocking if it was created via passing <tt>blocking: false</tt>
* to Fiber.new, or via Fiber.schedule.
*
* Note that, even if the method returns +false+, the fiber behaves differently
* only if Fiber.scheduler is set in the current thread.
*
* See the "Non-blocking fibers" section in class docs for details.
*
*/
VALUE
rb_fiber_blocking_p(VALUE fiber)
{
return (fiber_ptr(fiber)->blocking == 0) ? Qfalse : Qtrue;
}
/*
* call-seq:
* Fiber.blocking? -> false or 1
*
* Returns +false+ if the current fiber is non-blocking.
* Fiber is non-blocking if it was created via passing <tt>blocking: false</tt>
* to Fiber.new, or via Fiber.schedule.
*
* If the current Fiber is blocking, the method returns 1.
* Future developments may allow for situations where larger integers
* could be returned.
*
* Note that, even if the method returns +false+, Fiber behaves differently
* only if Fiber.scheduler is set in the current thread.
*
* See the "Non-blocking fibers" section in class docs for details.
*
*/
static VALUE
rb_f_fiber_blocking_p(VALUE klass)
{
rb_thread_t *thread = GET_THREAD();
unsigned blocking = thread->blocking;
if (blocking == 0)
return Qfalse;
return INT2NUM(blocking);
}
void
rb_fiber_close(rb_fiber_t *fiber)
{
fiber_status_set(fiber, FIBER_TERMINATED);
}
static void
rb_fiber_terminate(rb_fiber_t *fiber, int need_interrupt)
{
VALUE value = fiber->cont.value;
rb_fiber_t *next_fiber;
VM_ASSERT(FIBER_RESUMED_P(fiber));
rb_fiber_close(fiber);
coroutine_destroy(&fiber->context);
fiber->cont.machine.stack = NULL;
fiber->cont.machine.stack_size = 0;
next_fiber = return_fiber(true);
if (need_interrupt) RUBY_VM_SET_INTERRUPT(&next_fiber->cont.saved_ec);
fiber_switch(next_fiber, 1, &value, RB_NO_KEYWORDS, Qfalse, false);
}
VALUE
rb_fiber_resume_kw(VALUE fiber_value, int argc, const VALUE *argv, int kw_splat)
{
rb_fiber_t *fiber = fiber_ptr(fiber_value);
rb_fiber_t *current_fiber = fiber_current();
if (argc == -1 && FIBER_CREATED_P(fiber)) {
rb_raise(rb_eFiberError, "cannot raise exception on unborn fiber");
}
else if (FIBER_TERMINATED_P(fiber)) {
rb_raise(rb_eFiberError, "attempt to resume a terminated fiber");
}
else if (fiber == current_fiber) {
rb_raise(rb_eFiberError, "attempt to resume the current fiber");
}
else if (fiber->prev != NULL) {
rb_raise(rb_eFiberError, "attempt to resume a resumed fiber (double resume)");
}
else if (RTEST(fiber->resuming_fiber)) {
rb_raise(rb_eFiberError, "attempt to resume a resuming fiber");
}
else if (fiber->prev == NULL &&
(!fiber->yielding && fiber->status != FIBER_CREATED)) {
rb_raise(rb_eFiberError, "attempt to resume a transferring fiber");
}
return fiber_switch(fiber, argc, argv, kw_splat, fiber_value, false);
}
VALUE
rb_fiber_resume(VALUE fiber_value, int argc, const VALUE *argv)
{
return rb_fiber_resume_kw(fiber_value, argc, argv, RB_NO_KEYWORDS);
}
VALUE
rb_fiber_yield_kw(int argc, const VALUE *argv, int kw_splat)
{
return fiber_switch(return_fiber(false), argc, argv, kw_splat, Qfalse, true);
}
VALUE
rb_fiber_yield(int argc, const VALUE *argv)
{
return fiber_switch(return_fiber(false), argc, argv, RB_NO_KEYWORDS, Qfalse, true);
}
void
rb_fiber_reset_root_local_storage(rb_thread_t *th)
{
if (th->root_fiber && th->root_fiber != th->ec->fiber_ptr) {
th->ec->local_storage = th->root_fiber->cont.saved_ec.local_storage;
}
}
/*
* call-seq:
* fiber.alive? -> true or false
*
* Returns true if the fiber can still be resumed (or transferred
* to). After finishing execution of the fiber block this method will
* always return +false+. You need to <code>require 'fiber'</code>
* before using this method.
*/
VALUE
rb_fiber_alive_p(VALUE fiber_value)
{
return FIBER_TERMINATED_P(fiber_ptr(fiber_value)) ? Qfalse : Qtrue;
}
/*
* call-seq:
* fiber.resume(args, ...) -> obj
*
* Resumes the fiber from the point at which the last Fiber.yield was
* called, or starts running it if it is the first call to
* #resume. Arguments passed to resume will be the value of the
* Fiber.yield expression or will be passed as block parameters to
* the fiber's block if this is the first #resume.
*
* Alternatively, when resume is called it evaluates to the arguments passed
* to the next Fiber.yield statement inside the fiber's block
* or to the block value if it runs to completion without any
* Fiber.yield
*/
static VALUE
rb_fiber_m_resume(int argc, VALUE *argv, VALUE fiber)
{
return rb_fiber_resume_kw(fiber, argc, argv, rb_keyword_given_p());
}
static VALUE rb_fiber_transfer_kw(VALUE fiber_value, int argc, VALUE *argv, int kw_splat);
/*
* call-seq:
* fiber.raise -> obj
* fiber.raise(string) -> obj
* fiber.raise(exception [, string [, array]]) -> obj
*
* Raises an exception in the fiber at the point at which the last
* +Fiber.yield+ was called. If the fiber has not been started or has
* already run to completion, raises +FiberError+. If the fiber is
* yielding, it is resumed. If it is transferring, it is transferred into.
* But if it is resuming, raises +FiberError+.
*
* With no arguments, raises a +RuntimeError+. With a single +String+
* argument, raises a +RuntimeError+ with the string as a message. Otherwise,
* the first parameter should be the name of an +Exception+ class (or an
* object that returns an +Exception+ object when sent an +exception+
* message). The optional second parameter sets the message associated with
* the exception, and the third parameter is an array of callback information.
* Exceptions are caught by the +rescue+ clause of <code>begin...end</code>
* blocks.
*/
static VALUE
rb_fiber_raise(int argc, VALUE *argv, VALUE fiber_value)
{
rb_fiber_t *fiber = fiber_ptr(fiber_value);
VALUE exc = rb_make_exception(argc, argv);
if (RTEST(fiber->resuming_fiber)) {
rb_raise(rb_eFiberError, "attempt to raise a resuming fiber");
}
else if (FIBER_SUSPENDED_P(fiber) && !fiber->yielding) {
return rb_fiber_transfer_kw(fiber_value, -1, &exc, RB_NO_KEYWORDS);
}
else {
return rb_fiber_resume_kw(fiber_value, -1, &exc, RB_NO_KEYWORDS);
}
}
/*
* call-seq:
* fiber.backtrace -> array
* fiber.backtrace(start) -> array
* fiber.backtrace(start, count) -> array
* fiber.backtrace(start..end) -> array
*
* Returns the current execution stack of the fiber. +start+, +count+ and +end+ allow
* to select only parts of the backtrace.
*
* def level3
* Fiber.yield
* end
*
* def level2
* level3
* end
*
* def level1
* level2
* end
*
* f = Fiber.new { level1 }
*
* # It is empty before the fiber started
* f.backtrace
* #=> []
*
* f.resume
*
* f.backtrace
* #=> ["test.rb:2:in `yield'", "test.rb:2:in `level3'", "test.rb:6:in `level2'", "test.rb:10:in `level1'", "test.rb:13:in `block in <main>'"]
* p f.backtrace(1) # start from the item 1
* #=> ["test.rb:2:in `level3'", "test.rb:6:in `level2'", "test.rb:10:in `level1'", "test.rb:13:in `block in <main>'"]
* p f.backtrace(2, 2) # start from item 2, take 2
* #=> ["test.rb:6:in `level2'", "test.rb:10:in `level1'"]
* p f.backtrace(1..3) # take items from 1 to 3
* #=> ["test.rb:2:in `level3'", "test.rb:6:in `level2'", "test.rb:10:in `level1'"]
*
* f.resume
*
* # It is nil after the fiber is finished
* f.backtrace
* #=> nil
*
*/
static VALUE
rb_fiber_backtrace(int argc, VALUE *argv, VALUE fiber)
{
return rb_vm_backtrace(argc, argv, &fiber_ptr(fiber)->cont.saved_ec);
}
/*
* call-seq:
* fiber.backtrace_locations -> array
* fiber.backtrace_locations(start) -> array
* fiber.backtrace_locations(start, count) -> array
* fiber.backtrace_locations(start..end) -> array
*
* Like #backtrace, but returns each line of the execution stack as a
* Thread::Backtrace::Location. Accepts the same arguments as #backtrace.
*
* f = Fiber.new { Fiber.yield }
* f.resume
* loc = f.backtrace_locations.first
* loc.label #=> "yield"
* loc.path #=> "test.rb"
* loc.lineno #=> 1
*
*
*/
static VALUE
rb_fiber_backtrace_locations(int argc, VALUE *argv, VALUE fiber)
{
return rb_vm_backtrace_locations(argc, argv, &fiber_ptr(fiber)->cont.saved_ec);
}
/*
* call-seq:
* fiber.transfer(args, ...) -> obj
*
* Transfer control to another fiber, resuming it from where it last
* stopped or starting it if it was not resumed before. The calling
* fiber will be suspended much like in a call to
* Fiber.yield. You need to <code>require 'fiber'</code>
* before using this method.
*
* The fiber which receives the transfer call treats it much like
* a resume call. Arguments passed to transfer are treated like those
* passed to resume.
*
* The two style of control passing to and from fiber (one is #resume and
* Fiber::yield, another is #transfer to and from fiber) can't be freely
* mixed.
*
* * If the Fiber's lifecycle had started with transfer, it will never
* be able to yield or be resumed control passing, only
* finish or transfer back. (It still can resume other fibers that
* are allowed to be resumed.)
* * If the Fiber's lifecycle had started with resume, it can yield
* or transfer to another Fiber, but can receive control back only
* the way compatible with the way it was given away: if it had
* transferred, it only can be transferred back, and if it had
* yielded, it only can be resumed back. After that, it again can
* transfer or yield.
*
* If those rules are broken FiberError is raised.
*
* For an individual Fiber design, yield/resume is easier to use
* (the Fiber just gives away control, it doesn't need to think
* about who the control is given to), while transfer is more flexible
* for complex cases, allowing to build arbitrary graphs of Fibers
* dependent on each other.
*
*
* Example:
*
* require 'fiber'
*
* manager = nil # For local var to be visible inside worker block
*
* # This fiber would be started with transfer
* # It can't yield, and can't be resumed
* worker = Fiber.new { |work|
* puts "Worker: starts"
* puts "Worker: Performed #{work.inspect}, transferring back"
* # Fiber.yield # this would raise FiberError: attempt to yield on a not resumed fiber
* # manager.resume # this would raise FiberError: attempt to resume a resumed fiber (double resume)
* manager.transfer(work.capitalize)
* }
*
* # This fiber would be started with resume
* # It can yield or transfer, and can be transferred
* # back or resumed
* manager = Fiber.new {
* puts "Manager: starts"
* puts "Manager: transferring 'something' to worker"
* result = worker.transfer('something')
* puts "Manager: worker returned #{result.inspect}"
* # worker.resume # this would raise FiberError: attempt to resume a transferring fiber
* Fiber.yield # this is OK, the fiber transferred from and to, now it can yield
* puts "Manager: finished"
* }
*
* puts "Starting the manager"
* manager.resume
* puts "Resuming the manager"
* # manager.transfer # this would raise FiberError: attempt to transfer to a yielding fiber
* manager.resume
*
* <em>produces</em>
*
* Starting the manager
* Manager: starts
* Manager: transferring 'something' to worker
* Worker: starts
* Worker: Performed "something", transferring back
* Manager: worker returned "Something"
* Resuming the manager
* Manager: finished
*
*/
static VALUE
rb_fiber_m_transfer(int argc, VALUE *argv, VALUE fiber_value)
{
return rb_fiber_transfer_kw(fiber_value, argc, argv, rb_keyword_given_p());
}
static VALUE
rb_fiber_transfer_kw(VALUE fiber_value, int argc, VALUE *argv, int kw_splat)
{
rb_fiber_t *fiber = fiber_ptr(fiber_value);
if (RTEST(fiber->resuming_fiber)) {
rb_raise(rb_eFiberError, "attempt to transfer to a resuming fiber");
}
if (fiber->yielding) {
rb_raise(rb_eFiberError, "attempt to transfer to a yielding fiber");
}
return fiber_switch(fiber, argc, argv, kw_splat, Qfalse, false);
}
/*
* call-seq:
* Fiber.yield(args, ...) -> obj
*
* Yields control back to the context that resumed the fiber, passing
* along any arguments that were passed to it. The fiber will resume
* processing at this point when #resume is called next.
* Any arguments passed to the next #resume will be the value that
* this Fiber.yield expression evaluates to.
*/
static VALUE
rb_fiber_s_yield(int argc, VALUE *argv, VALUE klass)
{
return rb_fiber_yield_kw(argc, argv, rb_keyword_given_p());
}
/*
* call-seq:
* Fiber.current -> fiber
*
* Returns the current fiber. You need to <code>require 'fiber'</code>
* before using this method. If you are not running in the context of
* a fiber this method will return the root fiber.
*/
static VALUE
rb_fiber_s_current(VALUE klass)
{
return rb_fiber_current();
}
static VALUE
fiber_to_s(VALUE fiber_value)
{
const rb_fiber_t *fiber = fiber_ptr(fiber_value);
const rb_proc_t *proc;
char status_info[0x20];
if (RTEST(fiber->resuming_fiber)) {
snprintf(status_info, 0x20, " (%s by resuming)", fiber_status_name(fiber->status));
}
else {
snprintf(status_info, 0x20, " (%s)", fiber_status_name(fiber->status));
}
if (!rb_obj_is_proc(fiber->first_proc)) {
VALUE str = rb_any_to_s(fiber_value);
strlcat(status_info, ">", sizeof(status_info));
rb_str_set_len(str, RSTRING_LEN(str)-1);
rb_str_cat_cstr(str, status_info);
return str;
}
GetProcPtr(fiber->first_proc, proc);
return rb_block_to_s(fiber_value, &proc->block, status_info);
}
#ifdef HAVE_WORKING_FORK
void
rb_fiber_atfork(rb_thread_t *th)
{
if (th->root_fiber) {
if (&th->root_fiber->cont.saved_ec != th->ec) {
th->root_fiber = th->ec->fiber_ptr;
}
th->root_fiber->prev = 0;
}
}
#endif
#ifdef RB_EXPERIMENTAL_FIBER_POOL
static void
fiber_pool_free(void *ptr)
{
struct fiber_pool * fiber_pool = ptr;
RUBY_FREE_ENTER("fiber_pool");
fiber_pool_free_allocations(fiber_pool->allocations);
ruby_xfree(fiber_pool);
RUBY_FREE_LEAVE("fiber_pool");
}
static size_t
fiber_pool_memsize(const void *ptr)
{
const struct fiber_pool * fiber_pool = ptr;
size_t size = sizeof(*fiber_pool);
size += fiber_pool->count * fiber_pool->size;
return size;
}
static const rb_data_type_t FiberPoolDataType = {
"fiber_pool",
{NULL, fiber_pool_free, fiber_pool_memsize,},
0, 0, RUBY_TYPED_FREE_IMMEDIATELY
};
static VALUE
fiber_pool_alloc(VALUE klass)
{
struct fiber_pool * fiber_pool = RB_ALLOC(struct fiber_pool);
return TypedData_Wrap_Struct(klass, &FiberPoolDataType, fiber_pool);
}
static VALUE
rb_fiber_pool_initialize(int argc, VALUE* argv, VALUE self)
{
rb_thread_t *th = GET_THREAD();
VALUE size = Qnil, count = Qnil, vm_stack_size = Qnil;
struct fiber_pool * fiber_pool = NULL;
// Maybe these should be keyword arguments.
rb_scan_args(argc, argv, "03", &size, &count, &vm_stack_size);
if (NIL_P(size)) {
size = INT2NUM(th->vm->default_params.fiber_machine_stack_size);
}
if (NIL_P(count)) {
count = INT2NUM(128);
}
if (NIL_P(vm_stack_size)) {
vm_stack_size = INT2NUM(th->vm->default_params.fiber_vm_stack_size);
}
TypedData_Get_Struct(self, struct fiber_pool, &FiberPoolDataType, fiber_pool);
fiber_pool_initialize(fiber_pool, NUM2SIZET(size), NUM2SIZET(count), NUM2SIZET(vm_stack_size));
return self;
}
#endif
/*
* Document-class: FiberError
*
* Raised when an invalid operation is attempted on a Fiber, in
* particular when attempting to call/resume a dead fiber,
* attempting to yield from the root fiber, or calling a fiber across
* threads.
*
* fiber = Fiber.new{}
* fiber.resume #=> nil
* fiber.resume #=> FiberError: dead fiber called
*/
/*
* Document-class: Fiber::SchedulerInterface
*
* This is not an existing class, but documentation of the interface that Scheduler
* object should comply to in order to be used as argument to Fiber.scheduler and handle non-blocking
* fibers. See also the "Non-blocking fibers" section in Fiber class docs for explanations
* of some concepts.
*
* Scheduler's behavior and usage are expected to be as follows:
*
* * When the execution in the non-blocking Fiber reaches some blocking operation (like
* sleep, wait for a process, or a non-ready I/O), it calls some of the scheduler's
* hook methods, listed below.
* * Scheduler somehow registers what the current fiber is waiting on, and yields control
* to other fibers with Fiber.yield (so the fiber would be suspended while expecting its
* wait to end, and other fibers in the same thread can perform)
* * At the end of the current thread execution, the scheduler's method #close is called
* * The scheduler runs into a wait loop, checking all the blocked fibers (which it has
* registered on hook calls) and resuming them when the awaited resource is ready
* (e.g. I/O ready or sleep time elapsed).
*
* A typical implementation would probably rely for this closing loop on a gem like
* EventMachine[https://github.com/eventmachine/eventmachine] or
* Async[https://github.com/socketry/async].
*
* This way concurrent execution will be achieved transparently for every
* individual Fiber's code.
*
* Hook methods are:
*
* * #io_wait
* * #process_wait
* * #kernel_sleep
* * #block and #unblock
* * (the list is expanded as Ruby developers make more methods having non-blocking calls)
*
* When not specified otherwise, the hook implementations are mandatory: if they are not
* implemented, the methods trying to call hook will fail. To provide backward compatibility,
* in the future hooks will be optional (if they are not implemented, due to the scheduler
* being created for the older Ruby version, the code which needs this hook will not fail,
* and will just behave in a blocking fashion).
*
* It is also strongly recommended that the scheduler implements the #fiber method, which is
* delegated to by Fiber.schedule.
*
* Sample _toy_ implementation of the scheduler can be found in Ruby's code, in
* <tt>test/fiber/scheduler.rb</tt>
*
*/
#if 0 /* for RDoc */
/*
*
* Document-method: Fiber::SchedulerInterface#close
*
* Called when the current thread exits. The scheduler is expected to implement this
* method in order to allow all waiting fibers to finalize their execution.
*
* The suggested pattern is to implement the main event loop in the #close method.
*
*/
static VALUE
rb_fiber_scheduler_interface_close(VALUE self)
{
}
/*
* Document-method: SchedulerInterface#process_wait
* call-seq: process_wait(pid, flags)
*
* Invoked by Process::Status.wait in order to wait for a specified process.
* See that method description for arguments description.
*
* Suggested minimal implementation:
*
* Thread.new do
* Process::Status.wait(pid, flags)
* end.value
*
* This hook is optional: if it is not present in the current scheduler,
* Process::Status.wait will behave as a blocking method.
*
* Expected to return a Process::Status instance.
*/
static VALUE
rb_fiber_scheduler_interface_process_wait(VALUE self)
{
}
/*
* Document-method: SchedulerInterface#io_wait
* call-seq: io_wait(io, events, timeout)
*
* Invoked by IO#wait, IO#wait_readable, IO#wait_writable to ask whether the
* specified descriptor is ready for specified events within
* the specified +timeout+.
*
* +events+ is a bit mask of <tt>IO::READABLE</tt>, <tt>IO::WRITABLE</tt>, and
* <tt>IO::PRIORITY</tt>.
*
* Suggested implementation should register which Fiber is waiting for which
* resources and immediately calling Fiber.yield to pass control to other
* fibers. Then, in the #close method, the scheduler might dispatch all the
* I/O resources to fibers waiting for it.
*
* Expected to return the subset of events that are ready immediately.
*
*/
static VALUE
rb_fiber_scheduler_interface_io_wait(VALUE self)
{
}
/*
* Document-method: SchedulerInterface#kernel_sleep
* call-seq: kernel_sleep(duration = nil)
*
* Invoked by Kernel#sleep and Mutex#sleep and is expected to provide
* an implementation of sleeping in a non-blocking way. Implementation might
* register the current fiber in some list of "which fiber wait until what
* moment", call Fiber.yield to pass control, and then in #close resume
* the fibers whose wait period has elapsed.
*
*/
static VALUE
rb_fiber_scheduler_interface_kernel_sleep(VALUE self)
{
}
/*
* Document-method: SchedulerInterface#block
* call-seq: block(blocker, timeout = nil)
*
* Invoked by methods like Thread.join, and by Mutex, to signify that current
* Fiber is blocked until further notice (e.g. #unblock) or until +timeout+ has
* elapsed.
*
* +blocker+ is what we are waiting on, informational only (for debugging and
* logging). There are no guarantee about its value.
*
* Expected to return boolean, specifying whether the blocking operation was
* successful or not.
*/
static VALUE
rb_fiber_scheduler_interface_block(VALUE self)
{
}
/*
* Document-method: SchedulerInterface#unblock
* call-seq: unblock(blocker, fiber)
*
* Invoked to wake up Fiber previously blocked with #block (for example, Mutex#lock
* calls #block and Mutex#unlock calls #unblock). The scheduler should use
* the +fiber+ parameter to understand which fiber is unblocked.
*
* +blocker+ is what was awaited for, but it is informational only (for debugging
* and logging), and it is not guaranteed to be the same value as the +blocker+ for
* #block.
*
*/
static VALUE
rb_fiber_scheduler_interface_unblock(VALUE self)
{
}
/*
* Document-method: SchedulerInterface#fiber
* call-seq: fiber(&block)
*
* Implementation of the Fiber.schedule. The method is <em>expected</em> to immediately
* run the given block of code in a separate non-blocking fiber, and to return that Fiber.
*
* Minimal suggested implementation is:
*
* def fiber(&block)
* fiber = Fiber.new(blocking: false, &block)
* fiber.resume
* fiber
* end
*/
static VALUE
rb_fiber_scheduler_interface_fiber(VALUE self)
{
}
#endif
void
Init_Cont(void)
{
rb_thread_t *th = GET_THREAD();
size_t vm_stack_size = th->vm->default_params.fiber_vm_stack_size;
size_t machine_stack_size = th->vm->default_params.fiber_machine_stack_size;
size_t stack_size = machine_stack_size + vm_stack_size;
#ifdef _WIN32
SYSTEM_INFO info;
GetSystemInfo(&info);
pagesize = info.dwPageSize;
#else /* not WIN32 */
pagesize = sysconf(_SC_PAGESIZE);
#endif
SET_MACHINE_STACK_END(&th->ec->machine.stack_end);
fiber_pool_initialize(&shared_fiber_pool, stack_size, FIBER_POOL_INITIAL_SIZE, vm_stack_size);
fiber_initialize_keywords[0] = rb_intern_const("blocking");
fiber_initialize_keywords[1] = rb_intern_const("pool");
char * fiber_shared_fiber_pool_free_stacks = getenv("RUBY_SHARED_FIBER_POOL_FREE_STACKS");
if (fiber_shared_fiber_pool_free_stacks) {
shared_fiber_pool.free_stacks = atoi(fiber_shared_fiber_pool_free_stacks);
}
rb_cFiber = rb_define_class("Fiber", rb_cObject);
rb_define_alloc_func(rb_cFiber, fiber_alloc);
rb_eFiberError = rb_define_class("FiberError", rb_eStandardError);
rb_define_singleton_method(rb_cFiber, "yield", rb_fiber_s_yield, -1);
rb_define_singleton_method(rb_cFiber, "current", rb_fiber_s_current, 0);
rb_define_method(rb_cFiber, "initialize", rb_fiber_initialize, -1);
rb_define_method(rb_cFiber, "blocking?", rb_fiber_blocking_p, 0);
rb_define_method(rb_cFiber, "resume", rb_fiber_m_resume, -1);
rb_define_method(rb_cFiber, "raise", rb_fiber_raise, -1);
rb_define_method(rb_cFiber, "backtrace", rb_fiber_backtrace, -1);
rb_define_method(rb_cFiber, "backtrace_locations", rb_fiber_backtrace_locations, -1);
rb_define_method(rb_cFiber, "to_s", fiber_to_s, 0);
rb_define_alias(rb_cFiber, "inspect", "to_s");
rb_define_method(rb_cFiber, "transfer", rb_fiber_m_transfer, -1);
rb_define_method(rb_cFiber, "alive?", rb_fiber_alive_p, 0);
rb_define_singleton_method(rb_cFiber, "blocking?", rb_f_fiber_blocking_p, 0);
rb_define_singleton_method(rb_cFiber, "scheduler", rb_fiber_scheduler, 0);
rb_define_singleton_method(rb_cFiber, "set_scheduler", rb_fiber_set_scheduler, 1);
rb_define_singleton_method(rb_cFiber, "schedule", rb_f_fiber, -1);
//rb_define_global_function("Fiber", rb_f_fiber, -1);
#if 0 /* for RDoc */
rb_cFiberScheduler = rb_define_class_under(rb_cFiber, "SchedulerInterface", rb_cObject);
rb_define_method(rb_cFiberScheduler, "close", rb_fiber_scheduler_interface_close, 0);
rb_define_method(rb_cFiberScheduler, "process_wait", rb_fiber_scheduler_interface_process_wait, 0);
rb_define_method(rb_cFiberScheduler, "io_wait", rb_fiber_scheduler_interface_io_wait, 0);
rb_define_method(rb_cFiberScheduler, "kernel_sleep", rb_fiber_scheduler_interface_kernel_sleep, 0);
rb_define_method(rb_cFiberScheduler, "block", rb_fiber_scheduler_interface_block, 0);
rb_define_method(rb_cFiberScheduler, "unblock", rb_fiber_scheduler_interface_unblock, 0);
rb_define_method(rb_cFiberScheduler, "fiber", rb_fiber_scheduler_interface_fiber, 0);
#endif
#ifdef RB_EXPERIMENTAL_FIBER_POOL
rb_cFiberPool = rb_define_class("Pool", rb_cFiber);
rb_define_alloc_func(rb_cFiberPool, fiber_pool_alloc);
rb_define_method(rb_cFiberPool, "initialize", rb_fiber_pool_initialize, -1);
#endif
rb_provide("fiber.so");
}
RUBY_SYMBOL_EXPORT_BEGIN
void
ruby_Init_Continuation_body(void)
{
rb_cContinuation = rb_define_class("Continuation", rb_cObject);
rb_undef_alloc_func(rb_cContinuation);
rb_undef_method(CLASS_OF(rb_cContinuation), "new");
rb_define_method(rb_cContinuation, "call", rb_cont_call, -1);
rb_define_method(rb_cContinuation, "[]", rb_cont_call, -1);
rb_define_global_function("callcc", rb_callcc, 0);
}
RUBY_SYMBOL_EXPORT_END