зеркало из https://github.com/github/ruby.git
94 строки
3.3 KiB
C
94 строки
3.3 KiB
C
#ifndef COROUTINE_ASYNCIFY_CONTEXT_H
|
|
#define COROUTINE_ASYNCIFY_CONTEXT_H
|
|
|
|
/*
|
|
This is a coroutine implementation based on Binaryen's Asyncify transformation for WebAssembly.
|
|
|
|
This implementation is built on low-level ucontext-like API in wasm/fiber.c
|
|
This file is an adapter for the common coroutine interface and for stack manipulation.
|
|
wasm/fiber.c doesn't take care of stack to avoid duplicate management with this adapter.
|
|
|
|
* See also: wasm/fiber.c
|
|
*/
|
|
|
|
#include <stddef.h>
|
|
#include <stdio.h>
|
|
#include <stdint.h>
|
|
#include "wasm/asyncify.h"
|
|
#include "wasm/machine.h"
|
|
#include "wasm/fiber.h"
|
|
|
|
#define COROUTINE void __attribute__((__noreturn__))
|
|
|
|
static const int ASYNCIFY_CORO_DEBUG = 0;
|
|
|
|
struct coroutine_context
|
|
{
|
|
rb_wasm_fiber_context fc;
|
|
void *argument;
|
|
struct coroutine_context *from;
|
|
|
|
void *current_sp;
|
|
void *stack_base;
|
|
size_t size;
|
|
};
|
|
|
|
typedef COROUTINE(* coroutine_start)(struct coroutine_context *from, struct coroutine_context *self);
|
|
|
|
COROUTINE coroutine_trampoline(void * _start, void * _context);
|
|
|
|
static inline void coroutine_initialize_main(struct coroutine_context * context)
|
|
{
|
|
if (ASYNCIFY_CORO_DEBUG) fprintf(stderr, "[%s] entry (context = %p)\n", __func__, context);
|
|
// NULL fiber entry means it's the main fiber, and handled specially.
|
|
rb_wasm_init_context(&context->fc, NULL, NULL, NULL);
|
|
// mark the main fiber has already started
|
|
context->fc.is_started = true;
|
|
}
|
|
|
|
static inline void coroutine_initialize(struct coroutine_context *context, coroutine_start start, void *stack, size_t size)
|
|
{
|
|
// Linear stack pointer must be always aligned down to 16 bytes.
|
|
// https://github.com/WebAssembly/tool-conventions/blob/c74267a5897c1bdc9aa60adeaf41816387d3cd12/BasicCABI.md#the-linear-stack
|
|
uintptr_t sp = ((uintptr_t)stack + size) & ~0xF;
|
|
if (ASYNCIFY_CORO_DEBUG) fprintf(stderr, "[%s] entry (context = %p, stack = %p ... %p)\n", __func__, context, stack, (char *)sp);
|
|
rb_wasm_init_context(&context->fc, coroutine_trampoline, start, context);
|
|
// record the initial stack pointer position to restore it after resumption
|
|
context->current_sp = (char *)sp;
|
|
context->stack_base = stack;
|
|
context->size = size;
|
|
}
|
|
|
|
static inline struct coroutine_context * coroutine_transfer(struct coroutine_context * current, struct coroutine_context * target)
|
|
{
|
|
if (ASYNCIFY_CORO_DEBUG) fprintf(stderr, "[%s] entry (current = %p, target = %p)\n", __func__, current, target);
|
|
struct coroutine_context * previous = target->from;
|
|
|
|
target->from = current;
|
|
if (ASYNCIFY_CORO_DEBUG) fprintf(stderr, "[%s] current->current_sp = %p -> %p\n", __func__, current->current_sp, rb_wasm_get_stack_pointer());
|
|
// record the current stack pointer position to restore it after resumption
|
|
current->current_sp = rb_wasm_get_stack_pointer();
|
|
|
|
// suspend the current coroutine and resume another coroutine
|
|
|
|
rb_wasm_swapcontext(¤t->fc, &target->fc);
|
|
|
|
// after the original coroutine resumed
|
|
|
|
rb_wasm_set_stack_pointer(current->current_sp);
|
|
|
|
target->from = previous;
|
|
|
|
return target;
|
|
}
|
|
|
|
static inline void coroutine_destroy(struct coroutine_context * context)
|
|
{
|
|
if (ASYNCIFY_CORO_DEBUG) fprintf(stderr, "[%s] entry (context = %p)\n", __func__, context);
|
|
context->stack_base = NULL;
|
|
context->size = 0;
|
|
context->from = NULL;
|
|
}
|
|
|
|
#endif /* COROUTINE_ASYNCIFY_CONTEXT_H */
|