2.6 KiB
2.6 KiB
Instruction Deduplication — 2025‑11 Sweep (BinOp / Loop / Control Flow)
Purpose
- Remove duplicated lowering/handling of core instructions across Builder (AST→MIR), Program(JSON v0) Bridge, MIR loaders/emitters, and backends.
- Establish single‑source helpers (SSOT) per instruction family with narrow, testable APIs.
Scope (first pass)
- BinOp (Add/Sub/Mul/Div/Mod/BitOps)
- Loop (Continue/Break semantics: latch increment and PHI sealing)
- Control Flow (Compare/Branch/Jump/Phi placement and sealing)
- Const/Copy (uniform emission; string/int/float/bool coercions)
Hotspots (duplicated responsibility)
- BinOp
- Builder: src/mir/builder/ops.rs
- Program v0 bridge: src/runner/json_v0_bridge/lowering/expr.rs
- Loader/Emitter/Printer: src/runner/mir_json_v0.rs, src/runner/mir_json_emit.rs, src/mir/printer_helpers.rs
- LLVM Lower: src/backend/llvm/compiler/codegen/instructions/arith_ops.rs
- Loop (Continue/Break/PHI)
- Program v0 bridge: src/runner/json_v0_bridge/lowering/loop_.rs, lowering.rs (snapshot stacks)
- MIR phi core: src/mir/phi_core/loop_phi.rs, src/mir/loop_api.rs
- Control Flow
- Compare/Branch/Jump/Phi scattered in: json_v0_bridge/, mir/builder/emission/, mir/builder/if_form.rs, runner/mir_json_v0.rs
SSOT Helpers — Proposal
- mir/ssot/binop_lower.rs
- parse_binop(op_str, lhs, rhs) -> (BinaryOp, ValueId, ValueId)
- emit_binop(builder_or_func, dst, op, lhs, rhs)
- mir/ssot/loop_common.rs
- detect_increment_hint(stmts) -> Option<(name, step)>
- apply_increment_before_continue(func, cur_bb, vars, hint)
- seal_loop_phis(adapter, cond_bb, latch_bb, continue_snaps)
- mir/ssot/cf_common.rs
- emit_compare/branch/jump helpers; insert_phi_at_head
Adoption Plan (phased)
- Extract helpers with current logic (no behavior change). Add unit tests per helper.
- Replace callers (Builder & Program v0 bridge first). Keep backends untouched.
- Promote helpers to crate::mir::ssot::* public modules; update MIR JSON loader/emitter callsites.
- Enforce via clippy/doc: prefer helpers over ad‑hoc code.
Verification & Canaries
- BinOp: existing Core quick profile covers arithmetic/bitops; add two v0 Program cases for mixed ints.
- Loop: continue/break matrix (then/else variants, swapped equals, '!=' else) — already added under phase2039; keep green.
- Control Flow: phi placement/sealing stays under phi_core tests.
Acceptance (first pass)
- BinOp lowering in Builder and Program v0 bridge uses ssot/binop_lower exclusively.
- Continue semantics unified: apply_increment_before_continue used in both bridge and (if applicable) builder.
- No regressions in quick core profile; all new canaries PASS.