refactor: Vm 状态分组、dispatch 拆分为分发表、IC 辅助函数独立成模块

crates/oxide_vm/src/vm_state.rs

@@ -0,0 +1,57 @@
+//! Grouped `Vm` state sub-structs.
+//!
+//! `Vm` owns these as fields (`gc_state`, `symbols`, `iters`, `profiling`) so
+//! that workers refactoring one subsystem touch one struct instead of the
+//! central `Vm` god-struct. Per the project's parallel-dev decisions:
+//! Symbol/Iter/Profiling are full sinks (their logic is self-contained), while
+//! `GcState` is field-classification only — GC `mark`/`sweep`/`alloc_object`
+//! scan roots across *all* sub-structs and stay as `&mut Vm` methods.
+//!
+//! This file defines fields only; methods live with `Vm`.
+
+use std::cell::Cell;
+use std::collections::HashMap;
+
+use rustc_hash::FxBuildHasher;
+
+use oxide_types::object::{JsObject, JsString};
+use oxide_types::value::JsValue;
+
+use crate::session_gc::SessionGc;
+use crate::vm::ForInIter;
+
+/// Session-arena and garbage-collection bookkeeping.
+pub(crate) struct GcState {
+    pub(crate) session_epoch: bumpalo::Bump,
+    pub(crate) session_gc: SessionGc,
+    pub(crate) epoch_object_ptrs: Vec<*mut JsObject>,
+    pub(crate) session_object_ptrs: Vec<*mut JsObject>,
+    pub(crate) session_string_ptrs: Vec<*mut JsString>,
+    pub(crate) session_bytes_allocated: usize,
+    /// Long-lived forwarding map reused by GC sweep and promote.
+    /// `mem::take`'d out for use, `clear()`'d and put back — capacity retained
+    /// across collections, so no per-event `HashMap` allocation. `FxBuildHasher`
+    /// because the keys are raw pointers (collision resistance is irrelevant).
+    pub(crate) forwarding: HashMap<*mut JsObject, *mut JsObject, FxBuildHasher>,
+}
+
+/// `Symbol` interning state.
+pub(crate) struct SymbolState {
+    pub(crate) symbol_counter: u32,
+    pub(crate) symbol_descriptions: Vec<String>,
+    pub(crate) symbol_registry: HashMap<String, u32>,
+}
+
+/// Live iterator state for `for-in` / `for-of`.
+pub(crate) struct IterState {
+    pub(crate) for_in_iters: Vec<*mut ForInIter<'static>>,
+    pub(crate) for_of_iters: Vec<JsValue>,
+    pub(crate) last_for_of_result: JsValue,
+}
+
+/// Inline-cache hit/miss and instruction counters.
+pub(crate) struct ProfilingState {
+    pub(crate) ic_hits: Cell<u64>,
+    pub(crate) ic_misses: Cell<u64>,
+    pub(crate) instruction_count: u64,
+}