perf: DCE 管线复用，零删除免重建 CFG 与活集

Cargo.lock

@@ -1160,7 +1160,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_builtins"
-version = "0.16.10"
+version = "0.16.11"
 dependencies = [
  "chrono",
  "fast-float",
@@ -1185,7 +1185,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_bytecode"
-version = "0.16.10"
+version = "0.16.11"
 dependencies = [
  "num-bigint",
  "oxide_log",
@@ -1193,7 +1193,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_cfg"
-version = "0.16.10"
+version = "0.16.11"
 dependencies = [
  "oxide_bytecode",
  "oxide_emit",
@@ -1204,7 +1204,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_cli"
-version = "0.16.10"
+version = "0.16.11"
 dependencies = [
  "ansi_term",
  "bumpalo",
@@ -1228,7 +1228,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_code_cache"
-version = "0.16.10"
+version = "0.16.11"
 dependencies = [
  "lru",
  "oxide_bytecode",
@@ -1237,7 +1237,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_compiler"
-version = "0.16.10"
+version = "0.16.11"
 dependencies = [
  "oxide_bytecode",
  "oxide_cfg",
@@ -1257,7 +1257,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_dce"
-version = "0.16.10"
+version = "0.16.11"
 dependencies = [
  "oxide_bytecode",
  "oxide_cfg",
@@ -1271,7 +1271,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_emit"
-version = "0.16.10"
+version = "0.16.11"
 dependencies = [
  "num-bigint",
  "oxc_allocator",
@@ -1286,7 +1286,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_engine"
-version = "0.16.10"
+version = "0.16.11"
 dependencies = [
  "oxide_bytecode",
  "oxide_compiler",
@@ -1298,7 +1298,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_ir"
-version = "0.16.10"
+version = "0.16.11"
 dependencies = [
  "oxide_bytecode",
  "oxide_log",
@@ -1307,7 +1307,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_kernel"
-version = "0.16.10"
+version = "0.16.11"
 dependencies = [
  "bumpalo",
  "dashmap",
@@ -1321,7 +1321,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_liveness"
-version = "0.16.10"
+version = "0.16.11"
 dependencies = [
  "oxide_bytecode",
  "oxide_cfg",
@@ -1333,7 +1333,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_log"
-version = "0.16.10"
+version = "0.16.11"
 dependencies = [
  "tracing",
  "tracing-appender",
@@ -1342,11 +1342,11 @@ dependencies = [
 
 [[package]]
 name = "oxide_net"
-version = "0.16.10"
+version = "0.16.11"
 
 [[package]]
 name = "oxide_parser"
-version = "0.16.10"
+version = "0.16.11"
 dependencies = [
  "oxc_allocator",
  "oxc_ast",
@@ -1361,7 +1361,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_regalloc"
-version = "0.16.10"
+version = "0.16.11"
 dependencies = [
  "oxide_bytecode",
  "oxide_cfg",
@@ -1377,7 +1377,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_runtime_api"
-version = "0.16.10"
+version = "0.16.11"
 dependencies = [
  "num-bigint",
  "num-traits",
@@ -1390,7 +1390,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_test262"
-version = "0.16.10"
+version = "0.16.11"
 dependencies = [
  "oxide_bytecode",
  "oxide_compiler",
@@ -1410,7 +1410,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_types"
-version = "0.16.10"
+version = "0.16.11"
 dependencies = [
  "bumpalo",
  "dashmap",
@@ -1423,7 +1423,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_vm"
-version = "0.16.10"
+version = "0.16.11"
 dependencies = [
  "bumpalo",
  "chrono",

Cargo.toml

@@ -24,7 +24,7 @@ members = [
 ]
 
 [workspace.package]
-version = "0.16.10"
+version = "0.16.11"
 edition = "2021"
 license = "MIT"
 rust-version = "1.80"

crates/oxide_compiler/src/compiler.rs

@@ -93,24 +93,37 @@ impl Compiler {
 
     /// 统一 IR 后处理管线：（可选 DCE）→（可选 liveness/精确 DCE/RegAlloc）→
     /// bytecode（`lower`）→ 子模块拍平。
+    ///
+    /// 零删除时复用分析产物：DCE 零删除返回其 Pass A CFG（免重建），精确 DCE
+    /// 零删除返回 `live_reusable`（免第二轮 CFG/活集重建）。
     fn compile_ir(&self, mut ir: oxide_ir::IRFunction) -> Result<CompiledModule, String> {
         crate::compiler_debug!("compile_ir: after emit {} insts", ir.insts.len());
-        if self.enable_dce {
+        // DCE 零删除时返回 Pass A CFG 供 liveness 复用；有删除或 DCE 关闭时为 None（须重建）。
-            oxide_dce::dce(&mut ir); // 顶层函数；nested 不递归
+        let dce_cfg: Option<oxide_cfg::Cfg> = if self.enable_dce {
+            let cfg = oxide_dce::dce(&mut ir); // 顶层函数；nested 不递归
             crate::compiler_debug!("compile: after DCE {} insts", ir.insts.len());
-        }
+            cfg
+        } else {
+            None
+        };
         if self.enable_regalloc && !ir.const_overflow {
             // 优化管线：liveness → 精确 DCE → 重算 liveness → RegAlloc → 调用窗口编码
             // const_overflow 时跳过：程序已知无效（lower 报 "too many constants"），
             // 且超大常量池伴生的海量虚拟寄存器会使 liveness 稠密 bitset 爆内存。
-            let cfg = oxide_cfg::build_cfg(&ir);
+            // 零删除复用 DCE 的 Pass A CFG；DCE 关闭或有删除时重建
+            let cfg = dce_cfg.unwrap_or_else(|| oxide_cfg::build_cfg(&ir));
             let live = oxide_liveness::liveness(&ir, &cfg);
             // 精确 DCE 以第一轮 liveness 的指令级活集为输入，删除死指令
-            oxide_dce::dce_precise(&mut ir, &live);
+            let outcome = oxide_dce::dce_precise(&mut ir, &live);
-            // 删指令后 inst 下标位移，旧 CFG 失效，按新程序重建
+            // 零删除时函数未变，复用第一轮活集；有删除时 inst 下标位移，须重建
-            let cfg2 = oxide_cfg::build_cfg(&ir);
+            // CFG 并重算活集（重建的 CFG 仅服务活集计算，不单独命名）。
-            // 指令集已变，旧活集失效，须重算
+            let (_, live2) = if outcome.live_reusable {
-            let live2 = oxide_liveness::liveness(&ir, &cfg2);
+                (cfg, live)
+            } else {
+                let cfg2 = oxide_cfg::build_cfg(&ir);
+                let live2 = oxide_liveness::liveness(&ir, &cfg2);
+                (cfg2, live2)
+            };
             // 无可行染色 → RangeError 上抛
             oxide_regalloc::alloc(&mut ir, &live2)?;
             // RegAlloc 改写指令（虚拟寄存器→物理号并插入 spill）后旧活集失效，

crates/oxide_dce/src/lib.rs

@@ -12,6 +12,10 @@
 //!
 //! 精确二轮 `dce_precise`：liveness 驱动的死指令 + 局部死 STORE_VAR 删除，
 //! 消费 `oxide_liveness::LiveInfo`，mark-sweep 重建复用 Pass C。
+//!
+//! 两入口均暴露零删除事实供管线复用：`dce` 零删除时返回 Pass A 的 `Cfg`
+//! （`Some`，有删除为 `None`），`dce_precise` 返回 `PreciseOutcome`
+//! （`live_reusable` 标记第一轮活集是否仍有效）。
 
 mod dce_log;
 mod iter_sweep;
@@ -19,17 +23,24 @@ mod precise_sweep;
 mod reachability;
 mod rebuild;
 
+use oxide_cfg::Cfg;
 use oxide_ir::IRFunction;
 use oxide_liveness::LiveInfo;
 
 /// 死代码消除：块级不可达删除 + 全函数 use 计数迭代删除到不动点 + mark-sweep 重建。
-pub fn dce(f: &mut IRFunction) {
+///
-    // 空函数无指令可删，直接返回（no-op，f 不变）。
+/// 返回 `Some(Cfg)`：零删除（含空函数早退），insts 未变，Pass A 的 CFG 仍有效，
+/// 调用方可直接复用于 liveness（无需重建）。返回 `None`：有删除，insts 已 compact，
+/// 旧 CFG 失效，调用方须重建。
+pub fn dce(f: &mut IRFunction) -> Option<Cfg> {
+    // 空函数无指令可删，直接返回（no-op，f 不变）；退化 CFG 与编译器对空函数自建
+    // 的退化形态一致，保持「零删除 → Some」语义。
     if f.insts.is_empty() {
-        return;
+        return Some(oxide_cfg::build_cfg(f));
     }
     // Pass A：块级可达性（消费 build_cfg，Exception 边保守）→ 指令粒度 keep。
-    let mut keep = reachability::pass_a_reachable(f);
+    let cfg = oxide_cfg::build_cfg(f);
+    let mut keep = reachability::pass_a_reachable(f, &cfg);
     // Pass B：可达存活指令上全函数 use 计数迭代删除到不动点（连锁删上游写者）。
     iter_sweep::pass_b_dead_code(f, &mut keep);
     let dead = keep.iter().filter(|k| !**k).count();
@@ -39,20 +50,38 @@ pub fn dce(f: &mut IRFunction) {
     if dead > 0 {
         rebuild::pass_c_sweep(f, &keep);
     }
+    // 零删除 ⇒ 函数未变 ⇒ Pass A CFG 仍有效（复用守卫与零删除判定同源）。
+    if dead == 0 {
+        Some(cfg)
+    } else {
+        None
+    }
+}
+
+/// 精确二轮结果：`live_reusable` 为第一轮 liveness 是否仍可复用（零删除时真）。
+pub struct PreciseOutcome {
+    /// 零删除：inst 下标未位移，传入活集仍有效，调用方可复用第一轮 CFG 与活集。
+    pub live_reusable: bool,
 }
 
 /// 精确二轮：liveness 驱动的死指令 + 局部死 STORE_VAR 删除。
 ///
 /// 消费 oxide_liveness::LiveInfo（RegAlloc 管线传入；若 LiveInfo 已过期，重建 liveness
 /// 是调用方 RegAlloc 的职责，本 pass 不重复建分析引擎）。mark-sweep 重建复用既有 Pass C。
-pub fn dce_precise(f: &mut IRFunction, live: &LiveInfo) {
+/// 返回 `PreciseOutcome`：零删除时 `live_reusable` 为真（函数未变，第一轮活集仍有效）。
-    // 空函数无指令可删，直接返回（no-op，f 不变）。
+pub fn dce_precise(f: &mut IRFunction, live: &LiveInfo) -> PreciseOutcome {
+    // 空函数无指令可删，直接返回（no-op，f 不变）；未改任何指令，活集可复用。
     if f.insts.is_empty() {
-        return;
+        return PreciseOutcome {
+            live_reusable: true,
+        };
     }
-    // 维度守卫：live 与 insts 对齐才可信（删改后的过期 LiveInfo 索引错位会误删活指令）
+    // 维度守卫：live 与 insts 对齐才可信（删改后的过期 LiveInfo 索引错位会误删活指令）；
+    // 守卫不过时活集必过期，调用方须重建。
     if live.inst_live_after.len() != f.insts.len() {
-        return;
+        return PreciseOutcome {
+            live_reusable: false,
+        };
     }
     let mut keep = vec![true; f.insts.len()];
     precise_sweep::pass_dead_with_liveness(f, live, &mut keep);
@@ -61,4 +90,8 @@ pub fn dce_precise(f: &mut IRFunction, live: &LiveInfo) {
     if dead > 0 {
         rebuild::pass_c_sweep(f, &keep);
     }
+    // 零删除 ⇒ 函数未变 ⇒ 第一轮活集仍有效（复用守卫与零删除判定同源）。
+    PreciseOutcome {
+        live_reusable: dead == 0,
+    }
 }

crates/oxide_dce/src/reachability.rs

@@ -3,12 +3,13 @@
 //! 消费 `oxide_cfg::build_cfg` 的 Cfg，从 entry 沿 succs DFS（**遍历含 EdgeKind::Exception 边**，
 //! catch/finally 入口强制可达），不可达块的全部指令标记删除。
 
-use oxide_cfg::build_cfg;
+use oxide_cfg::Cfg;
 use oxide_ir::IRFunction;
 
 /// 从 entry 可达的指令位图（keep 前置：不可达指令为 false）。
-pub(super) fn pass_a_reachable(f: &IRFunction) -> Vec<bool> {
+///
-    let cfg = build_cfg(f);
+/// 消费调用方传入的 `Cfg`（`dce` 建一次复用，不重复构建）。
+pub(super) fn pass_a_reachable(f: &IRFunction, cfg: &Cfg) -> Vec<bool> {
     let mut reachable = vec![false; cfg.blocks.len()];
     let mut stack = vec![cfg.entry];
     while let Some(b) = stack.pop() {
@@ -47,7 +48,8 @@ mod tests {
         f.insts.push(Inst::load_const(Operand::Reg(1), 0));
         f.insts
             .push(Inst::new(OpCode::RETURN, Operand::Reg(1), Operand::None, Operand::None));
-        let keep = pass_a_reachable(&f);
+        let cfg = oxide_cfg::build_cfg(&f);
+        let keep = pass_a_reachable(&f, &cfg);
         assert!(keep.iter().all(|k| *k), "线性函数全指令可达");
     }
 
@@ -63,7 +65,8 @@ mod tests {
         f.label_pos = vec![Some(1)];
         f.label_count = 1;
 
-        let keep = pass_a_reachable(&f);
+        let cfg = oxide_cfg::build_cfg(&f);
+        let keep = pass_a_reachable(&f, &cfg);
         assert!(keep[0], "RETURN 指令可达");
         assert!(!keep[1] && !keep[2], "return 后死块不可达");
     }
@@ -83,7 +86,8 @@ mod tests {
         f.label_pos = vec![Some(3)];
         f.label_count = 1;
 
-        let keep = pass_a_reachable(&f);
+        let cfg = oxide_cfg::build_cfg(&f);
+        let keep = pass_a_reachable(&f, &cfg);
         assert!(keep[3] && keep[4], "catch 入口经 Exception 边强制可达");
     }
 }

crates/oxide_dce/tests/conservative_unit.rs

@@ -10,7 +10,7 @@ use oxide_ir::IRFunction;
 #[test]
 fn empty_function_unchanged() {
     let mut f = IRFunction::new();
-    dce(&mut f);
+    let _ = dce(&mut f);
     assert!(f.insts.is_empty());
     assert!(f.label_pos.is_empty());
     assert_eq!(f.label_count, 0);
@@ -29,10 +29,10 @@ fn dce_is_idempotent() {
         .push(Inst::new(OpCode::RETURN, Operand::Reg(5), Operand::None, Operand::None)); // 4
     f.label_pos = vec![Some(0)];
 
-    dce(&mut f);
+    let _ = dce(&mut f);
     let once_insts = f.insts.clone();
     let once_labels = f.label_pos.clone();
-    dce(&mut f);
+    let _ = dce(&mut f);
     assert_eq!(f.insts, once_insts, "二次 dce 后 insts 不变");
     assert_eq!(f.label_pos, once_labels, "二次 dce 后 label_pos 不变");
 }
@@ -50,7 +50,7 @@ fn if_else_both_branches_reachable_kept() {
     f.label_pos = vec![Some(3), Some(4)];
     f.label_count = 2;
 
-    dce(&mut f);
+    let _ = dce(&mut f);
     assert_eq!(f.insts.len(), 5, "双分支全保留");
     assert_eq!(f.label_pos, vec![Some(3), Some(4)], "存活 label 重映射到新下标");
     assert_eq!(f.label_count, 2, "label_count 保持原值，不参与重建");
@@ -71,7 +71,7 @@ fn all_live_function_unchanged() {
 
     let before_insts = f.insts.clone();
     let before_labels = f.label_pos.clone();
-    dce(&mut f);
+    let _ = dce(&mut f);
     assert_eq!(f.insts, before_insts, "全存活时 insts 逐位不变");
     assert_eq!(f.label_pos, before_labels, "全存活时 label_pos 逐位不变");
     assert_eq!(f.label_count, 1, "label_count 保持原值");

crates/oxide_dce/tests/precise_eq.rs

@@ -17,7 +17,7 @@ fn run_source(src: &str, precise: bool) -> Result<JsValue, String> {
     let mut ir = oxide_emit::Emitter::new()
         .emit_program(&program, false, false)
         .expect("emit failed");
-    oxide_dce::dce(&mut ir); // 保守轮恒定（两跑一致）
+    let _ = oxide_dce::dce(&mut ir); // 保守轮恒定（两跑一致）
     if precise {
         let cfg = oxide_cfg::build_cfg(&ir);
         let live = oxide_liveness::liveness(&ir, &cfg);
@@ -78,7 +78,7 @@ fn top_level_store_var_survives_precise() {
     let mut ir = oxide_emit::Emitter::new()
         .emit_program(&program, false, false)
         .expect("emit failed");
-    oxide_dce::dce(&mut ir);
+    let _ = oxide_dce::dce(&mut ir);
     let cfg = oxide_cfg::build_cfg(&ir);
     let live = oxide_liveness::liveness(&ir, &cfg);
     oxide_dce::dce_precise(&mut ir, &live);
@@ -104,7 +104,7 @@ fn precise_removes_dead_local_store() {
         .expect("emit failed");
     assert_eq!(ir.nested.len(), 1);
     let mut sub = ir.nested[0].clone();
-    oxide_dce::dce(&mut sub);
+    let _ = oxide_dce::dce(&mut sub);
     let cfg = oxide_cfg::build_cfg(&sub);
     let live = oxide_liveness::liveness(&sub, &cfg);
     oxide_dce::dce_precise(&mut sub, &live);

crates/oxide_dce/tests/runtime_eq.rs

@@ -17,7 +17,7 @@ fn run_source(src: &str, dce: bool) -> Result<JsValue, String> {
         .emit_program(&program, false, false)
         .expect("emit failed");
     if dce {
-        oxide_dce::dce(&mut ir);
+        let _ = oxide_dce::dce(&mut ir);
     }
     let module = oxide_ir::lower::lower(&ir).expect("lower failed");
     let mut vm = Vm::new();
@@ -80,7 +80,7 @@ fn top_level_store_var_kept() {
     let mut ir = oxide_emit::Emitter::new()
         .emit_program(&program, false, false)
         .expect("emit failed");
-    oxide_dce::dce(&mut ir);
+    let _ = oxide_dce::dce(&mut ir);
     let module = oxide_ir::lower::lower(&ir).expect("lower failed");
     let has_store_var = module
         .bytecode

crates/oxide_regalloc/tests/nested_parent_slot_regress.rs

@@ -19,7 +19,7 @@ fn run_source(src: &str, regalloc: bool) -> (bool, String) {
         Ok(i) => i,
         Err(e) => return (false, format!("emit error: {e}")),
     };
-    oxide_dce::dce(&mut ir);
+    let _ = oxide_dce::dce(&mut ir);
     if regalloc {
         let cfg = oxide_cfg::build_cfg(&ir);
         let live = oxide_liveness::liveness(&ir, &cfg);

crates/oxide_regalloc/tests/reg_count.rs

@@ -6,7 +6,7 @@ fn n_registers(src: &str, regalloc: bool) -> Result<u8, String> {
     let mut ir = oxide_emit::Emitter::new()
         .emit_program(&program, false, false)
         .expect("emit failed");
-    oxide_dce::dce(&mut ir);
+    let _ = oxide_dce::dce(&mut ir);
     if regalloc {
         let cfg = oxide_cfg::build_cfg(&ir);
         let live = oxide_liveness::liveness(&ir, &cfg);

crates/oxide_regalloc/tests/regalloc_samples.rs

@@ -13,7 +13,7 @@ fn compile_source(src: &str, regalloc: bool) -> Result<CompiledModule, String> {
     let mut ir = oxide_emit::Emitter::new()
         .emit_program(&program, false, false)
         .expect("emit failed");
-    oxide_dce::dce(&mut ir);
+    let _ = oxide_dce::dce(&mut ir);
     if regalloc {
         let cfg = oxide_cfg::build_cfg(&ir);
         let live = oxide_liveness::liveness(&ir, &cfg);

crates/oxide_regalloc/tests/runtime_eq.rs

@@ -16,7 +16,7 @@ fn run_source(src: &str, regalloc: bool) -> Result<JsValue, String> {
     let mut ir = oxide_emit::Emitter::new()
         .emit_program(&program, false, false)
         .expect("emit failed");
-    oxide_dce::dce(&mut ir);
+    let _ = oxide_dce::dce(&mut ir);
     if regalloc {
         let cfg = oxide_cfg::build_cfg(&ir);
         let live = oxide_liveness::liveness(&ir, &cfg);
@@ -128,7 +128,7 @@ fn large_and_spill_samples_run_correctly() {
     let allocator = oxide_parser::Allocator::default();
     let program = oxide_parser::parse(&allocator, &src_spill).expect("parse");
     let mut ir = oxide_emit::Emitter::new().emit_program(&program, false, false).expect("emit");
-    oxide_dce::dce(&mut ir);
+    let _ = oxide_dce::dce(&mut ir);
     let cfg = oxide_cfg::build_cfg(&ir);
     let live = oxide_liveness::liveness(&ir, &cfg);
     oxide_dce::dce_precise(&mut ir, &live);