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refactor: VM 主实现非派发段按职责拆入 vm 子模块
This commit is contained in:
@@ -0,0 +1,373 @@
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//! GC 根遍历与执行期收集钩子：根统一枚举、搬移后指针重写、执行期两档
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//! 收集入口（安全点门控）与 session GC 账目统计访问器。
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use oxide_types::object::{Cell, JsObject};
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use oxide_types::value::JsValue;
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use super::frames::Completion;
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use super::Vm;
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use crate::session_gc::SessionGc;
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impl Vm {
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/// GC 根收集的统一遍历（对象与字符串都产出）。与 `rewrite_values` 字段一一对应。
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/// 覆盖执行核心的全部 JsValue 持有点：regs/帧/各栈段/cell/在途异常与完成/
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/// 挂起信号/迭代器/微任务/global。新增执行字段必须同时登记在此与
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/// `rewrite_values`。
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pub(crate) fn for_each_value(&self, mut f: impl FnMut(JsValue)) {
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for value in &self.regs {
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f(*value);
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}
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// 各代际 immutables 缓存含 session BigInt（new_bigint 分配），未入根则被
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// sweep 释放 → 常量池加载时悬垂。perm 字符串无害（不在 session 集合中）。
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for table in self.tables.values() {
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for once_lock in &table.immutables {
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if let Some(immutable_vec) = once_lock.get() {
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for &value in immutable_vec.iter() {
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f(value);
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}
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}
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}
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}
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for frame in &self.frames {
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f(frame.saved_this);
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f(frame.saved_new_target);
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f(frame.callee);
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f(frame.constructed_this.unwrap_or(JsValue::undefined()));
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}
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for &v in &self.save_stack {
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f(v);
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}
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// spill 栈是 session GC 根（漏根 → 溢出值被回收 → use-after-free）。
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for &v in &self.spill_stack {
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f(v);
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}
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for cell_vec in &self.cell_stack {
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for &cell_ptr in cell_vec {
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if cell_ptr.is_null() {
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continue;
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}
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// SAFETY: cell 由 session_epoch 分配，本 session 内指针有效。
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f(unsafe { &*cell_ptr }.value);
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}
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}
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f(self.exception_value.unwrap_or(JsValue::undefined()));
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f(self.pending_exception.unwrap_or(JsValue::undefined()));
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f(self.last_uncaught_value.unwrap_or(JsValue::undefined()));
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// 悬挂的 return 完成持有返回值，是 GC 根。
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if let Some(Completion::Return { value, .. }) = self.pending_completion {
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f(value);
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}
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f(self.generator_suspended.unwrap_or(JsValue::undefined()));
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f(self.delegated_iterator.unwrap_or(JsValue::undefined()));
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f(self.async_context.unwrap_or(JsValue::undefined()));
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f(self.async_gen_context.unwrap_or(JsValue::undefined()));
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f(self.inline_callee.unwrap_or(JsValue::undefined()));
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// 标签模板对象缓存：命中的模板对象是 GC 根（未根 → sweep 搬移/回收悬垂）。
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for &cached in self.template_objects.values() {
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f(cached);
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}
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for &entry in &self.iters.for_of_iters {
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f(entry.iterator);
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f(entry.last_result);
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}
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// 微任务队列中的处理器/能力/值都是 GC 根。
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for job in &self.job_queue {
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crate::promise::for_each_job_value(job, &mut f);
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}
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for iter in &self.iters.for_in_iters {
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if iter.is_null() {
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continue;
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}
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// SAFETY: for_in_iters 存放由当前 VM epoch 拥有的存活迭代器指针。
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unsafe {
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for (v, _si) in (*(*iter)).keys.iter() {
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f(*v);
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}
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}
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}
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f(JsValue::from_js_object(self.session.global_object().as_ptr() as *mut JsObject));
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}
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/// GC 指针重写（session 搬移后调用）。与 `for_each_value` 字段一一对应。
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pub(crate) fn rewrite_values(&mut self, mut rewrite: impl FnMut(JsValue) -> JsValue) {
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for value in &mut self.regs {
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*value = rewrite(*value);
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}
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for frame in &mut self.frames {
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frame.saved_this = rewrite(frame.saved_this);
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frame.saved_new_target = rewrite(frame.saved_new_target);
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frame.callee = rewrite(frame.callee);
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frame.constructed_this = frame.constructed_this.map(&mut rewrite);
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}
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for v in &mut self.save_stack {
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*v = rewrite(*v);
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}
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for v in &mut self.spill_stack {
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*v = rewrite(*v);
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}
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for cell_vec in &mut self.cell_stack {
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for &mut cell_ptr in cell_vec.iter_mut() {
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if cell_ptr.is_null() {
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continue;
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}
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// SAFETY: cell 由 session_epoch 分配，本 session 内指针有效。
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let cell = unsafe { &mut *cell_ptr };
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cell.value = rewrite(cell.value);
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}
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}
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self.exception_value = self.exception_value.map(&mut rewrite);
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self.pending_exception = self.pending_exception.map(&mut rewrite);
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self.last_uncaught_value = self.last_uncaught_value.map(&mut rewrite);
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for cached in self.template_objects.values_mut() {
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*cached = rewrite(*cached);
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}
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self.pending_completion = self.pending_completion.map(|completion| match completion {
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Completion::Return {
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value,
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remaining_finally,
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for_of_count,
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for_in_count,
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} => Completion::Return {
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value: rewrite(value),
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remaining_finally,
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for_of_count,
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for_in_count,
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},
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other => other,
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});
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self.generator_suspended = self.generator_suspended.map(&mut rewrite);
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self.delegated_iterator = self.delegated_iterator.map(&mut rewrite);
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self.async_context = self.async_context.map(&mut rewrite);
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self.async_gen_context = self.async_gen_context.map(&mut rewrite);
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self.inline_callee = self.inline_callee.map(&mut rewrite);
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for entry in &mut self.iters.for_of_iters {
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entry.iterator = rewrite(entry.iterator);
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entry.last_result = rewrite(entry.last_result);
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}
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// 微任务队列中的值随 sweep 重写。
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for job in &mut self.job_queue {
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crate::promise::rewrite_job_values(job, &mut rewrite);
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}
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for iter in &mut self.iters.for_in_iters {
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if iter.is_null() {
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continue;
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}
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// SAFETY: for_in_iters 存放由当前 VM epoch 拥有的存活迭代器指针。
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unsafe {
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for (v, _si) in (*(*iter)).keys.iter_mut() {
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*v = rewrite(*v);
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}
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}
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}
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let global_ptr = self.session.global_object().as_ptr() as *mut JsObject;
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if !global_ptr.is_null() {
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// SAFETY: KernelSession 在 VM 生命周期内拥有 global_object。
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unsafe {
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(*global_ptr).rewrite_object_values(rewrite);
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}
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}
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}
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pub(crate) fn for_each_root(&self, f: impl FnMut(JsValue)) {
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// 统一遍历：根收集与指针重写共用同一字段清单。
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self.for_each_value(f);
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}
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pub(crate) fn maybe_collect_session_gc(&mut self) {
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let mut session_gc = std::mem::take(&mut self.gc_state.session_gc);
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session_gc.maybe_collect(self);
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self.gc_state.session_gc = session_gc;
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}
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/// 执行期字符串阈值回收：仅回收 session 字符串（跳过对象搬移）。热路径只在
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/// 超阈值后进入，`mem::take` 不承担每次分配的开销。
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pub(crate) fn maybe_collect_session_strings(&mut self) {
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let mut session_gc = std::mem::take(&mut self.gc_state.session_gc);
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session_gc.maybe_collect_strings_only(self);
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self.gc_state.session_gc = session_gc;
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}
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/// 门控子句二：三型状态盒（生成器/异步函数/异步生成器）的
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/// `suspended.for_in_iters` 是否非空。
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///
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/// ForInIter body 分配于 epoch arena，收集换新 Bump 即时失效在表迭代器；
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/// 挂起帧把迭代器搬入状态盒（`vm.iters` 不可见），故须逐状态盒扫描。
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///
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/// # 边界与前提
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/// - 扫描 epoch + session 两份对象表——挂起状态盒宿主对象可能尚未晋升；
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/// - 挂起帧的 keys 经状态盒边收为 GC 根（被枚举对象不误释放），悬的是
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/// 迭代器 body，故按指针扫 `for_in_iters`；
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/// - 保守口径：死对象的状态盒同样计入（持挂起 for-in 的 run 放弃执行期
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/// 收集），正确性优先于收益；
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/// - 新增挂起态持有者须在此登记。
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pub(crate) fn suspended_holds_for_in(&self) -> bool {
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let holds = |&ptr: &*mut JsObject| {
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if ptr.is_null() {
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return false;
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}
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// SAFETY: 对象表登记的指针，arena 存活期内有效。
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let obj = unsafe { &*ptr };
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match obj.type_tag {
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JsObject::OBJ_TYPE_GENERATOR => crate::generator::generator_holds_suspended_for_in(obj),
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JsObject::OBJ_TYPE_ASYNC => crate::async_func::async_holds_suspended_for_in(obj),
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JsObject::OBJ_TYPE_ASYNC_GENERATOR => {
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crate::async_generator::async_generator_holds_suspended_for_in(obj)
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}
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_ => false,
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}
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};
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self.gc_state.epoch_object_ptrs.iter().any(holds) || self.gc_state.session_object_ptrs.iter().any(holds)
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}
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/// 执行期两档收集的 dispatch 安全点入口：仅在循环顶
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/// （`native_call_depth == 0`，无 builtin 局部裸指针、dispatch 未重入）
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/// 由触发块调用；先门控后收集。
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///
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/// # 边界与前提
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/// - 子句一（活跃 for-in，O(1)）未过：免费重试，不设锚；
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/// - 子句二（状态盒扫描，O(对象数)）未过：重扫按包络增长一个阈值设锚，
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/// 避免持挂起 for-in 的 run 每指令边界重扫；
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/// - 门控过但无对象可回收时仍跑一轮（mark + 换新 Bump），水位同点抬高，
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/// 触发间距由包络增量控制。
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pub(crate) fn maybe_collect_in_run(&mut self) {
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if !self.iters.for_in_iters.is_empty() {
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return;
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}
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if self.gc_state.gc_gate_retry_alloc > self.run_alloc_bytes() {
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return;
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}
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if self.suspended_holds_for_in() {
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self.gc_state.gc_gate_retry_alloc =
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self.run_alloc_bytes().saturating_add(self.gc_state.gc_threshold_cached);
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return;
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}
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let mut session_gc = std::mem::take(&mut self.gc_state.session_gc);
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session_gc.collect_in_run(self);
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self.gc_state.session_gc = session_gc;
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}
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/// 只读访问 session GC 的统计（回收次数、存活/死亡对象数、释放字节等）。
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pub fn session_gc_stats(&self) -> &SessionGc {
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&self.gc_state.session_gc
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}
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/// 当前 session arena 中存活（已晋升）的对象数量。
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pub fn session_object_count(&self) -> usize {
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self.gc_state.session_object_ptrs.len()
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}
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/// session 当前分配的字节数（对象 + 存活字符串）。
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pub fn session_bytes_allocated(&self) -> usize {
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self.gc_state.session_bytes_allocated
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}
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/// 执行期 session 堆账目的峰值高水位（顶层指令边界采样，全量重置清零）。
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pub fn session_bytes_peak(&self) -> usize {
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self.gc_state.session_bytes_peak
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}
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/// 双 arena（epoch + session 对象）当前 chunk 已分配字节之和。
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///
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/// # 注意事项
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/// reset 边界读 = 换新 Bump 后空 arena 恰 0（空 chunk 哨兵计 0）；
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/// run 中途读 = 当前 chunk 用量（非全 arena 口径——run 计量走
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/// [`Self::run_alloc_bytes`]，勿据此断言）。
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pub fn arena_retained_bytes(&self) -> usize {
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self.epoch.bump().allocated_bytes() + self.gc_state.session_epoch.allocated_bytes()
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}
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/// 本 run 累计分配字节的高水位：`run_alloc_bytes` 的顶层指令边界
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/// 采样上界，run 边界（reset/full_reset）重起算。留存内存观测锚。
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pub fn run_alloc_peak(&self) -> usize {
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self.gc_state.run_alloc_peak
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}
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/// 本 run 累计分配字节：epoch arena + session 对象 arena + session 手工堆
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/// 账目（session 串 + session 对象及其属性向量 + GC 后补回的 BigInt）。
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/// 单次 run 内单调不减（执行期对象不回收、
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/// 串 GC 只降手工堆账目而 arena 不减）；run 边界（reset）后重新起算，
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/// 供单 run 分配上限判定。
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///
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/// 注意：手工堆账目只在 promote/字符串分配/GC 回收点更新，执行期对象
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/// 属性区（元素/属性向量扩容）增长对其不可见——上限判定须配合
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/// [`Self::run_alloc_bytes_full`] 的深采样层。
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pub(crate) fn run_alloc_bytes(&self) -> usize {
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self.epoch.bump().allocated_bytes()
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+ self.gc_state.session_epoch.allocated_bytes()
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+ self.gc_state.session_bytes_allocated
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}
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/// 本 run 累计分配字节的全量重算版：base 只取两个 arena 计数器
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/// （epoch + session 对象 arena），手工堆逐一重算——已登记对象的堆数据
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/// （属性/元素向量 + upvalue 列表 + native 状态盒）、session 串、BigInt
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/// 与 upvalue cell 的容量。三分量（arena / 对象堆数据 / 串-BigInt-cell）
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/// 两两不相交，且不含 session 手工堆账目——无交叠不双计，重算即属性区
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/// 扩容等账目盲区的兜底。
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pub(crate) fn run_alloc_bytes_full(&self) -> u64 {
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let mut bytes = (self.epoch.bump().allocated_bytes() + self.gc_state.session_epoch.allocated_bytes()) as u64;
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for &ptr in self
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.gc_state
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.epoch_object_ptrs
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.iter()
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.chain(self.gc_state.session_object_ptrs.iter())
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{
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if ptr.is_null() {
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continue;
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}
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// SAFETY: ptr 来自对象表登记，dispatch 安全点处仍有效。
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bytes += SessionGc::object_heap_data_bytes(unsafe { &*ptr });
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}
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for &ptr in &self.gc_state.session_string_ptrs {
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// SAFETY: ptr 来自字符串表登记，收尾前始终有效。
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bytes += (std::mem::size_of::<oxide_types::object::JsString>() + unsafe { (*ptr).payload_bytes() }) as u64;
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}
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bytes += (self.gc_state.session_bigint_ptrs.borrow().len() * std::mem::size_of::<num_bigint::BigInt>()) as u64;
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bytes += (self.gc_state.session_cell_ptrs.borrow().len() * std::mem::size_of::<Cell>()) as u64;
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bytes
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}
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/// 无条件执行一次完整 session GC（mark + 移动式 sweep + 串/BigInt 清扫）。
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///
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/// # 副作用
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/// - 存活对象复制进新 session arena，全部根与原生盒按转发表重写；
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/// `session_bytes_allocated` 重置为清扫后的存活字节。
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///
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/// # 注意事项
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/// - 须在执行外的安全点调用（无在途 builtin 局部裸指针、dispatch 未重入）；
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/// 执行期触发仍走水位路径，本入口供事后观测（如基准测 workload 后留存堆）。
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pub fn collect_session_gc(&mut self) {
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let mut session_gc = std::mem::take(&mut self.gc_state.session_gc);
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session_gc.collect(self);
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self.gc_state.session_gc = session_gc;
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}
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/// 当前 epoch 中已分配并跟踪的对象数量（未晋升到 session 的临时对象）。
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pub fn epoch_object_count(&self) -> usize {
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self.gc_state.epoch_object_ptrs.len()
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}
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|
||||
/// inline cache 命中率（0.0~1.0），用于观测 IC 预热效果。
|
||||
pub fn ic_hit_rate(&self) -> f64 {
|
||||
self.profiling.ic_hit_rate()
|
||||
}
|
||||
|
||||
/// 累计执行的指令数（profiling）。
|
||||
pub fn instruction_count(&self) -> u64 {
|
||||
self.profiling.instruction_count
|
||||
}
|
||||
|
||||
/// 全局 symbol 注册表中已注册的 key 数量。
|
||||
pub fn symbol_registry_len(&self) -> usize {
|
||||
self.symbols.registry_len()
|
||||
}
|
||||
|
||||
/// inline cache 命中次数。
|
||||
pub fn ic_hit_count(&self) -> u64 {
|
||||
self.profiling.ic_hits.get()
|
||||
}
|
||||
|
||||
/// inline cache 未命中次数。
|
||||
pub fn ic_miss_count(&self) -> u64 {
|
||||
self.profiling.ic_misses.get()
|
||||
}
|
||||
}
|
||||
Reference in New Issue
Block a user