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cont.c
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cont.c
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/**********************************************************************
cont.c -
$Author$
created at: Thu May 23 09:03:43 2007
Copyright (C) 2007 Koichi Sasada
**********************************************************************/
#include "internal.h"
#include "vm_core.h"
#include "gc.h"
#include "eval_intern.h"
/* FIBER_USE_NATIVE enables Fiber performance improvement using system
* dependent method such as make/setcontext on POSIX system or
* CreateFiber() API on Windows.
* This hack make Fiber context switch faster (x2 or more).
* However, it decrease maximum number of Fiber. For example, on the
* 32bit POSIX OS, ten or twenty thousands Fiber can be created.
*
* Details is reported in the paper "A Fast Fiber Implementation for Ruby 1.9"
* in Proc. of 51th Programming Symposium, pp.21--28 (2010) (in Japanese).
*/
#if !defined(FIBER_USE_NATIVE)
# if defined(HAVE_GETCONTEXT) && defined(HAVE_SETCONTEXT)
# if 0
# elif defined(__NetBSD__)
/* On our experience, NetBSD doesn't support using setcontext() and pthread
* simultaneously. This is because pthread_self(), TLS and other information
* are represented by stack pointer (higher bits of stack pointer).
* TODO: check such constraint on configure.
*/
# define FIBER_USE_NATIVE 0
# elif defined(__sun)
/* On Solaris because resuming any Fiber caused SEGV, for some reason.
*/
# define FIBER_USE_NATIVE 0
# elif defined(__ia64)
/* At least, Linux/ia64's getcontext(3) doesn't save register window.
*/
# define FIBER_USE_NATIVE 0
# elif defined(__GNU__)
/* GNU/Hurd doesn't fully support getcontext, setcontext, makecontext
* and swapcontext functions. Disabling their usage till support is
* implemented. More info at
* http://darnassus.sceen.net/~hurd-web/open_issues/glibc/#getcontext
*/
# define FIBER_USE_NATIVE 0
# else
# define FIBER_USE_NATIVE 1
# endif
# elif defined(_WIN32)
# define FIBER_USE_NATIVE 1
# endif
#endif
#if !defined(FIBER_USE_NATIVE)
#define FIBER_USE_NATIVE 0
#endif
#if FIBER_USE_NATIVE
#ifndef _WIN32
#include <unistd.h>
#include <sys/mman.h>
#include <ucontext.h>
#endif
#define RB_PAGE_SIZE (pagesize)
#define RB_PAGE_MASK (~(RB_PAGE_SIZE - 1))
static long pagesize;
#endif /*FIBER_USE_NATIVE*/
#define CAPTURE_JUST_VALID_VM_STACK 1
enum context_type {
CONTINUATION_CONTEXT = 0,
FIBER_CONTEXT = 1,
ROOT_FIBER_CONTEXT = 2
};
struct cont_saved_vm_stack {
VALUE *ptr;
#ifdef CAPTURE_JUST_VALID_VM_STACK
size_t slen; /* length of stack (head of th->ec.vm_stack) */
size_t clen; /* length of control frames (tail of th->ec.vm_stack) */
#endif
};
typedef struct rb_context_struct {
enum context_type type;
int argc;
VALUE self;
VALUE value;
struct cont_saved_vm_stack saved_vm_stack;
struct {
VALUE *stack;
VALUE *stack_src;
size_t stack_size;
#ifdef __ia64
VALUE *register_stack;
VALUE *register_stack_src;
int register_stack_size;
#endif
} machine;
rb_execution_context_t saved_ec;
rb_jmpbuf_t jmpbuf;
rb_ensure_entry_t *ensure_array;
rb_ensure_list_t *ensure_list;
VALUE thread_value;
} 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(fib) ((fib)->status == FIBER_CREATED)
#define FIBER_RESUMED_P(fib) ((fib)->status == FIBER_RESUMED)
#define FIBER_SUSPENDED_P(fib) ((fib)->status == FIBER_SUSPENDED)
#define FIBER_TERMINATED_P(fib) ((fib)->status == FIBER_TERMINATED)
#define FIBER_RUNNABLE_P(fib) (FIBER_CREATED_P(fib) || FIBER_SUSPENDED_P(fib))
#if FIBER_USE_NATIVE && !defined(_WIN32)
#define MAX_MACHINE_STACK_CACHE 10
static int machine_stack_cache_index = 0;
typedef struct machine_stack_cache_struct {
void *ptr;
size_t size;
} machine_stack_cache_t;
static machine_stack_cache_t machine_stack_cache[MAX_MACHINE_STACK_CACHE];
static machine_stack_cache_t terminated_machine_stack;
#endif
struct rb_fiber_struct {
rb_context_t cont;
VALUE first_proc;
struct rb_fiber_struct *prev;
const enum fiber_status status;
/* If a fiber invokes "transfer",
* then this fiber can't "resume" any more after that.
* You shouldn't mix "transfer" and "resume".
*/
int transferred;
#if FIBER_USE_NATIVE
#ifdef _WIN32
void *fib_handle;
#else
ucontext_t context;
/* Because context.uc_stack.ss_sp and context.uc_stack.ss_size
* are not necessarily valid after makecontext() or swapcontext(),
* they are saved in these variables for later use.
*/
void *ss_sp;
size_t ss_size;
#endif
#endif
};
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_status_set(const rb_fiber_t *fib, enum fiber_status s)
{
if (0) fprintf(stderr, "fib: %p, status: %s -> %s\n", fib, fiber_status_name(fib->status), fiber_status_name(s));
VM_ASSERT(!FIBER_TERMINATED_P(fib));
VM_ASSERT(fib->status != s);
*((enum fiber_status *)&fib->status) = s;
}
static const rb_data_type_t cont_data_type, fiber_data_type;
static VALUE rb_cContinuation;
static VALUE rb_cFiber;
static VALUE rb_eFiberError;
#define GetContPtr(obj, ptr) \
TypedData_Get_Struct((obj), rb_context_t, &cont_data_type, (ptr))
#define GetFiberPtr(obj, ptr) do {\
TypedData_Get_Struct((obj), rb_fiber_t, &fiber_data_type, (ptr)); \
if (!(ptr)) rb_raise(rb_eFiberError, "uninitialized fiber"); \
} while (0)
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)
static VALUE
cont_thread_value(const rb_context_t *cont)
{
return cont->thread_value;
}
static void
cont_mark(void *ptr)
{
rb_context_t *cont = ptr;
RUBY_MARK_ENTER("cont");
rb_gc_mark(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_thread_t *th = rb_thread_ptr(cont_thread_value(cont));
const rb_fiber_t *fib = (rb_fiber_t*)cont;
if ((th->ec.fiber != fib) && !FIBER_TERMINATED_P(fib)) {
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)
{
rb_context_t *cont = ptr;
RUBY_FREE_ENTER("cont");
RUBY_FREE_UNLESS_NULL(cont->saved_ec.vm_stack);
#if FIBER_USE_NATIVE
if (cont->type == CONTINUATION_CONTEXT) {
/* cont */
ruby_xfree(cont->ensure_array);
RUBY_FREE_UNLESS_NULL(cont->machine.stack);
}
else {
/* fiber */
const rb_fiber_t *fib = (rb_fiber_t*)cont;
const rb_thread_t *const th = GET_THREAD();
#ifdef _WIN32
if (th && th->ec.fiber != fib && cont->type != ROOT_FIBER_CONTEXT) {
/* don't delete root fiber handle */
if (fib->fib_handle) {
DeleteFiber(fib->fib_handle);
}
}
#else /* not WIN32 */
if (th && th->ec.fiber != fib) {
if (fib->ss_sp) {
if (cont->type == ROOT_FIBER_CONTEXT) {
rb_bug("Illegal root fiber parameter");
}
munmap((void*)fib->ss_sp, fib->ss_size);
}
}
else {
/* It may reached here when finalize */
/* TODO examine whether it is a bug */
/* rb_bug("cont_free: release self"); */
}
#endif
}
#else /* not FIBER_USE_NATIVE */
ruby_xfree(cont->ensure_array);
RUBY_FREE_UNLESS_NULL(cont->machine.stack);
#endif
#ifdef __ia64
RUBY_FREE_UNLESS_NULL(cont->machine.register_stack);
#endif
RUBY_FREE_UNLESS_NULL(cont->saved_vm_stack.ptr);
/* 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);
}
#ifdef __ia64
if (cont->machine.register_stack) {
size += cont->machine.register_stack_size * sizeof(*cont->machine.register_stack);
}
#endif
return size;
}
static void
fiber_verify(const rb_fiber_t *fib)
{
#if VM_CHECK_MODE > 0
switch (fib->status) {
case FIBER_RESUMED:
VM_ASSERT(fib->cont.saved_ec.vm_stack == NULL);
break;
case FIBER_SUSPENDED:
VM_ASSERT(fib->cont.saved_ec.vm_stack != NULL);
break;
case FIBER_CREATED:
case FIBER_TERMINATED:
/* TODO */
break;
default:
VM_UNREACHABLE(fiber_verify);
}
#endif
}
void
rb_fiber_mark_self(const rb_fiber_t *fib)
{
if (fib)
rb_gc_mark(fib->cont.self);
}
static void
fiber_mark(void *ptr)
{
rb_fiber_t *fib = ptr;
RUBY_MARK_ENTER("cont");
fiber_verify(fib);
rb_gc_mark(fib->first_proc);
rb_fiber_mark_self(fib->prev);
cont_mark(&fib->cont);
RUBY_MARK_LEAVE("cont");
}
static void
fiber_free(void *ptr)
{
rb_fiber_t *fib = ptr;
RUBY_FREE_ENTER("fiber");
if (fib->cont.type != ROOT_FIBER_CONTEXT &&
fib->cont.saved_ec.local_storage) {
st_free_table(fib->cont.saved_ec.local_storage);
}
cont_free(&fib->cont);
RUBY_FREE_LEAVE("fiber");
}
static size_t
fiber_memsize(const void *ptr)
{
const rb_fiber_t *fib = ptr;
size_t size = 0;
size = sizeof(*fib);
if (fib->cont.type != ROOT_FIBER_CONTEXT &&
fib->cont.saved_ec.local_storage != NULL) {
size += st_memsize(fib->cont.saved_ec.local_storage);
}
size += cont_memsize(&fib->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);
#ifdef __ia64
th->machine.register_stack_end = rb_ia64_bsp();
#endif
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);
#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 const rb_data_type_t cont_data_type = {
"continuation",
{cont_mark, cont_free, cont_memsize,},
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_thread->machine.stack_end should be NULL */
/* because it may happen GC afterward */
sec->machine.stack_end = NULL;
#ifdef __ia64
sec->machine.register_stack_start = NULL;
sec->machine.register_stack_end = NULL;
#endif
}
static void
cont_init(rb_context_t *cont, rb_thread_t *th)
{
/* save thread context */
cont_save_thread(cont, th);
cont->thread_value = th->self;
cont->saved_ec.local_storage = NULL;
cont->saved_ec.local_storage_recursive_hash = Qnil;
cont->saved_ec.local_storage_recursive_hash_for_trace = Qnil;
}
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;
}
static VALUE
cont_capture(volatile int *volatile stat)
{
rb_context_t *volatile cont;
rb_thread_t *th = GET_THREAD();
volatile VALUE contval;
rb_execution_context_t *ec = &th->ec;
THREAD_MUST_BE_RUNNING(th);
rb_vm_stack_to_heap(th);
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
cont->saved_ec.vm_stack = 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;
}
}
static inline void
fiber_restore_thread(rb_thread_t *th, rb_fiber_t *fib)
{
th->ec = fib->cont.saved_ec;
fib->cont.saved_ec.vm_stack = NULL;
VM_ASSERT(th->ec.vm_stack != NULL);
}
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;
const rb_fiber_t *fib;
fib = th->ec.fiber = sec->fiber;
if (fib == NULL) fib = th->root_fiber;
if (fib && fib->cont.saved_ec.vm_stack) {
th->ec.vm_stack_size = fib->cont.saved_ec.vm_stack_size;
th->ec.vm_stack = fib->cont.saved_ec.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 + sec->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.safe_level = sec->safe_level;
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;
th->ec.trace_arg = sec->trace_arg;
VM_ASSERT(th->ec.vm_stack != NULL);
}
else {
/* fiber */
fiber_restore_thread(th, (rb_fiber_t*)cont);
}
}
#if FIBER_USE_NATIVE
#ifdef _WIN32
static void
fiber_set_stack_location(void)
{
rb_thread_t *th = GET_THREAD();
VALUE *ptr;
SET_MACHINE_STACK_END(&ptr);
th->ec.machine.stack_start = (void*)(((VALUE)ptr & RB_PAGE_MASK) + STACK_UPPER((void *)&ptr, 0, RB_PAGE_SIZE));
}
static VOID CALLBACK
fiber_entry(void *arg)
{
fiber_set_stack_location();
rb_fiber_start();
}
#else /* _WIN32 */
/*
* 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
static char*
fiber_machine_stack_alloc(size_t size)
{
char *ptr;
if (machine_stack_cache_index > 0) {
if (machine_stack_cache[machine_stack_cache_index - 1].size == (size / sizeof(VALUE))) {
ptr = machine_stack_cache[machine_stack_cache_index - 1].ptr;
machine_stack_cache_index--;
machine_stack_cache[machine_stack_cache_index].ptr = NULL;
machine_stack_cache[machine_stack_cache_index].size = 0;
}
else{
/* TODO handle multiple machine stack size */
rb_bug("machine_stack_cache size is not canonicalized");
}
}
else {
void *page;
STACK_GROW_DIR_DETECTION;
errno = 0;
ptr = mmap(NULL, size, PROT_READ | PROT_WRITE, FIBER_STACK_FLAGS, -1, 0);
if (ptr == MAP_FAILED) {
rb_raise(rb_eFiberError, "can't alloc machine stack to fiber: %s", strerror(errno));
}
/* guard page setup */
page = ptr + STACK_DIR_UPPER(size - RB_PAGE_SIZE, 0);
if (mprotect(page, RB_PAGE_SIZE, PROT_NONE) < 0) {
rb_raise(rb_eFiberError, "mprotect failed");
}
}
return ptr;
}
#endif
static void
fiber_initialize_machine_stack_context(rb_fiber_t *fib, size_t size)
{
rb_execution_context_t *sec = &fib->cont.saved_ec;
#ifdef _WIN32
# if defined(_MSC_VER) && _MSC_VER <= 1200
# define CreateFiberEx(cs, stacksize, flags, entry, param) \
CreateFiber((stacksize), (entry), (param))
# endif
fib->fib_handle = CreateFiberEx(size - 1, size, 0, fiber_entry, NULL);
if (!fib->fib_handle) {
/* try to release unnecessary fibers & retry to create */
rb_gc();
fib->fib_handle = CreateFiberEx(size - 1, size, 0, fiber_entry, NULL);
if (!fib->fib_handle) {
rb_raise(rb_eFiberError, "can't create fiber");
}
}
sec->machine.stack_maxsize = size;
#else /* not WIN32 */
ucontext_t *context = &fib->context;
char *ptr;
STACK_GROW_DIR_DETECTION;
getcontext(context);
ptr = fiber_machine_stack_alloc(size);
context->uc_link = NULL;
context->uc_stack.ss_sp = ptr;
context->uc_stack.ss_size = size;
fib->ss_sp = ptr;
fib->ss_size = size;
makecontext(context, rb_fiber_start, 0);
sec->machine.stack_start = (VALUE*)(ptr + STACK_DIR_UPPER(0, size));
sec->machine.stack_maxsize = size - RB_PAGE_SIZE;
#endif
#ifdef __ia64
sth->machine.register_stack_maxsize = sth->machine.stack_maxsize;
#endif
}
NOINLINE(static void fiber_setcontext(rb_fiber_t *newfib, rb_fiber_t *oldfib));
static void
fiber_setcontext(rb_fiber_t *newfib, rb_fiber_t *oldfib)
{
rb_thread_t *th = GET_THREAD();
/* save oldfib's machine stack / TODO: is it needed? */
if (!FIBER_TERMINATED_P(oldfib)) {
STACK_GROW_DIR_DETECTION;
SET_MACHINE_STACK_END(&th->ec.machine.stack_end);
if (STACK_DIR_UPPER(0, 1)) {
oldfib->cont.machine.stack_size = th->ec.machine.stack_start - th->ec.machine.stack_end;
oldfib->cont.machine.stack = th->ec.machine.stack_end;
}
else {
oldfib->cont.machine.stack_size = th->ec.machine.stack_end - th->ec.machine.stack_start;
oldfib->cont.machine.stack = th->ec.machine.stack_start;
}
}
/* exchange machine_stack_start between oldfib and newfib */
oldfib->cont.saved_ec.machine.stack_start = th->ec.machine.stack_start;
/* oldfib->machine.stack_end should be NULL */
oldfib->cont.saved_ec.machine.stack_end = NULL;
/* restore thread context */
fiber_restore_thread(th, newfib);
#ifndef _WIN32
if (!newfib->context.uc_stack.ss_sp && th->root_fiber != newfib) {
rb_bug("non_root_fiber->context.uc_stac.ss_sp should not be NULL");
}
#endif
/* swap machine context */
#ifdef _WIN32
SwitchToFiber(newfib->fib_handle);
#else
swapcontext(&oldfib->context, &newfib->context);
#endif
}
#endif
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*)(&cont->jmpbuf))->Frame =
((_JUMP_BUFFER*)(&buf))->Frame;
}
#endif
if (cont->machine.stack_src) {
FLUSH_REGISTER_WINDOWS;
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);
#if 0
{/* the above lines make cc-mode.el confused so much */}
#endif
int rb_dummy_false = 0;
NORETURN(NOINLINE(static void register_stack_extend(rb_context_t *, VALUE *, VALUE *)));
static void
register_stack_extend(rb_context_t *cont, VALUE *vp, 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, vp, (VALUE*)rb_ia64_bsp());
}
cont_restore_0(cont, vp);
}
#undef C
#undef E
#endif
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);
}
#ifdef __ia64
#define cont_restore_0(cont, vp) register_stack_extend((cont), (vp), (VALUE*)rb_ia64_bsp())
#endif
/*
* 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 <code>callcc</code> 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 "\n#{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