mirror of
https://github.com/pjh456/OxideJS.git
synced 2026-10-24 02:31:13 +08:00
fix: try/finally 支持 break/continue/return 穿越 finally（completion 机制）
This commit is contained in:
@@ -1,4 +1,4 @@
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use crate::vm::{FrameContinuation, TryHandler, Vm};
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use crate::vm::{Completion, FrameContinuation, TryHandler, Vm};
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use crate::vm_trace;
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use oxide_bytecode::opcode;
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use oxide_types::object::PropAttributes;
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@@ -124,6 +124,83 @@ impl Vm {
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}
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}
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/// break 完成：`crossed`（rd 槽）为 emit 词法算出的逃出 finally 域数。
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/// 逐个穿越 finally 后跳转到目标；crossed 为 0 时直接跳转。
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pub(crate) fn dispatch_break(&mut self, instr: u32) {
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let offset = opcode::offset16(instr) as isize;
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let target_pc = ((self.pc as isize) + offset - 1) as usize;
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let crossed = opcode::rd(instr) as usize;
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if let Some(finally_pc) = self.record_completion(Completion::Break { target_pc, remaining_finally: crossed }) {
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self.pc = finally_pc;
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} else {
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self.pc = target_pc;
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}
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}
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/// continue 完成：同 break，目标为循环继续位置。
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pub(crate) fn dispatch_continue(&mut self, instr: u32) {
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let offset = opcode::offset16(instr) as isize;
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let target_pc = ((self.pc as isize) + offset - 1) as usize;
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let crossed = opcode::rd(instr) as usize;
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if let Some(finally_pc) = self.record_completion(Completion::Continue { target_pc, remaining_finally: crossed }) {
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self.pc = finally_pc;
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} else {
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self.pc = target_pc;
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}
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}
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/// 记录一次控制流完成：穿越 `remaining_finally` 个 finally 体后执行完成本身。
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///
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/// # 步骤
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/// 1. 新完成覆盖在途异常/完成（break/continue/return 是新的突然完成）。
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/// 2. 从栈顶向下扫描：逃出的 catch-only handler 弹出；正在执行的 finally 体
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/// （`finally_active`）被覆盖弹出并计数；未进入的包裹 finally 计数后进入。
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/// 3. 计数耗尽（全部跨越的 finally 已进入或已覆盖）→ 返回 None（快速路径）。
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///
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/// # 边界与前提
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/// - 只扫描当前帧深度（`frames.len()`）的 handler；调用者的 handler 不参与——
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/// break/continue 词法不跨函数，return 也只逃出本函数 finally。
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///
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/// # 副作用
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/// - 清空 `pending_exception`/`pending_completion`，弹出被逃出的 handler。
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fn record_completion(&mut self, c: Completion) -> Option<usize> {
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self.pending_exception = None;
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self.pending_error_kind = None;
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self.pending_completion = None;
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let depth = self.frames.len();
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let mut remaining = c.remaining_finally();
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loop {
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if remaining == 0 {
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return None;
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}
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let (frame_depth, finally_pc, finally_active) = {
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let Some(h) = self.try_stack.last() else {
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return None;
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};
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(h.frame_depth, h.finally_pc, h.finally_active)
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};
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if frame_depth != depth {
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return None;
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}
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let Some(fp) = finally_pc else {
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// 逃出的 catch-only handler：丢弃防泄漏。
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self.try_stack.pop();
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continue;
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};
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remaining -= 1;
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if finally_active {
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// 正在执行本 finally 体：本完成覆盖它，弹出。
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self.try_stack.pop();
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continue;
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}
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self.try_stack.last_mut().unwrap().finally_active = true;
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self.pending_completion = Some(c.with_remaining(remaining));
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return Some(fp);
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}
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}
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/// return 完成：`crossed` = 当前帧深度内全部 finally handler 数（return 逃出整个
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/// 函数，途中被覆盖的 finally 体也在内），穿越后实际返回。
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pub(crate) fn dispatch_return(&mut self, rd: usize) -> Result<Option<JsValue>, String> {
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let result = self.regs[rd];
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crate::vm_debug!(
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@@ -131,6 +208,23 @@ impl Vm {
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self.frames.len(),
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self.frames.last().map(|f| f.return_addr).unwrap_or(0)
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);
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let crossed = self
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.try_stack
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.iter()
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.filter(|h| h.frame_depth == self.frames.len() && h.finally_pc.is_some())
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.count();
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if let Some(finally_pc) =
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self.record_completion(Completion::Return { value: result, remaining_finally: crossed })
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{
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self.pc = finally_pc;
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return Ok(None);
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}
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self.do_return(result)
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}
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/// 实际执行返回：弹出当前帧并交付返回值（供 dispatch_return 与 finally 完成
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/// 恢复共用）。
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fn do_return(&mut self, result: JsValue) -> Result<Option<JsValue>, String> {
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if let Some(frame) = self.frames.pop() {
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self.cell_stack.pop();
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let construct_result_reg = frame.construct_result_reg;
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@@ -139,10 +233,9 @@ impl Vm {
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let continuation = frame.continuation;
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let callee_this = self.regs[254];
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vm_trace!(
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"RETURN frame: continuation={:?}, derived={}, result_reg={}",
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"RETURN frame: continuation={:?}, derived={}",
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continuation,
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is_derived_constructor,
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rd
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is_derived_constructor
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);
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self.restore_frame(frame);
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if let (Some(target_reg), Some(constructed_this)) = (construct_result_reg, constructed_this) {
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@@ -192,6 +285,7 @@ impl Vm {
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self.try_stack.push(TryHandler {
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catch_pc,
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finally_pc: None,
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finally_active: false,
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frame_depth: self.frames.len(),
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for_of_depth: self.iters.for_of_iters.len(),
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});
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@@ -209,20 +303,75 @@ impl Vm {
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self.try_stack.push(TryHandler {
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catch_pc: None,
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finally_pc: Some(finally_pc),
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finally_active: false,
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frame_depth: self.frames.len(),
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for_of_depth: self.iters.for_of_iters.len(),
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});
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}
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pub(crate) fn dispatch_try_finally_end(&mut self) -> Result<bool, String> {
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/// finally 完成分发点：弹出当前 handler 后统一恢复在途异常或控制流完成。
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///
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/// # 步骤
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/// 1. 弹出刚执行完的 finally handler。
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/// 2. 优先恢复在途异常（unwind 继续向外展开）。
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/// 3. 否则查 `pending_completion`：仍有剩余 finally 体则进入下一个（递减计数）；
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/// 耗尽则执行完成本身（break/continue 跳转目标，return 交付返回值）。
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///
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/// # 返回值
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/// `Ok(Some(value))` = 函数返回；`Ok(None)` = 正常继续 dispatch。
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pub(crate) fn dispatch_try_finally_end(&mut self) -> Result<Option<JsValue>, String> {
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vm_trace!("TRY_FINALLY_END has_pending_exc={}", self.pending_exception.is_some());
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self.try_stack.pop();
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if self.pending_exception.is_some() && self.exception_value.is_none() {
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self.exception_value = self.pending_exception.take();
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self.unwind().map(|_| true)
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} else {
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self.pending_exception = None;
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Ok(false)
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self.unwind()?;
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return Ok(None);
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}
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self.pending_exception = None;
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let Some(c) = self.pending_completion.take() else {
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return Ok(None);
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};
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if c.remaining_finally() > 0 {
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let next = c.with_remaining(c.remaining_finally() - 1);
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if let Some(finally_pc) = self.find_next_finally() {
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self.pending_completion = Some(next);
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self.pc = finally_pc;
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return Ok(None);
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}
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}
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match c {
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Completion::Break { target_pc, .. } | Completion::Continue { target_pc, .. } => {
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self.pc = target_pc;
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Ok(None)
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}
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Completion::Return { value, .. } => self.do_return(value),
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}
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}
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/// 找下一个未被覆盖的包裹 finally 并进入（resume 路径用）：弹出途中被逃出的
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/// catch-only 与防御性的 active handler。无更多返回 None。
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fn find_next_finally(&mut self) -> Option<usize> {
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let depth = self.frames.len();
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loop {
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let (frame_depth, finally_pc, finally_active) = {
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let Some(h) = self.try_stack.last() else {
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return None;
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};
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(h.frame_depth, h.finally_pc, h.finally_active)
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};
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if frame_depth != depth {
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return None;
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}
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let Some(fp) = finally_pc else {
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self.try_stack.pop();
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continue;
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};
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if finally_active {
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self.try_stack.pop();
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continue;
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}
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self.try_stack.last_mut().unwrap().finally_active = true;
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return Some(fp);
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}
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}
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}
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