f0608e9bb1
## 🎉 完了項目 - ✅ plugin_box_legacy.rs削除（7.7KB、参照ゼロ確認済み） - ✅ REMOVEDコメント整理（encode.rs簡潔化） - ✅ venv削除（143MB節約、.gitignoreは既存） - ✅ llvm_legacyスタブ化（8KB、compile_error!による安全化） ## 🏆 成果 - **リポジトリサイズ改善**: 151MB削減 - **コード整理**: レガシーコード安全にアーカイブ - **プラグインファースト**: StrictPluginFirst継続動作 ## ✅ 検証完了 - cargo build --release --features llvm (警告のみ、エラーなし) - LLVMハーネス実行: print出力正常 - プラグイン動作: StringBox等正常動作 codex先生の戦略に従った安全な段階的削除を実行 Co-Authored-By: codex <noreply@anthropic.com>
30 lines
2.2 KiB
Markdown
30 lines
2.2 KiB
Markdown
## MIR PHI Policy (Phase‑15)
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Status
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- Default: PHI‑on. MIR builders always emit SSA `Phi` nodes at merge heads, and verifiers run with full dominance checks.
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- Legacy fallback: Set `NYASH_MIR_NO_PHI=1` to enforce the former edge‑copy mode (PHI‑off) for targeted debug sessions.
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- LLVM: The llvmlite harness still validates and, when necessary, rewires PHIs, but it no longer compensates for missing SSA form in the input.
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Rationale
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- Break/continue correctness: PHI‑off exposed MIR generation bugs around loop exits; keeping PHIs generated in the core builder avoids silent value reuse mistakes.
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- ChatGPT Pro design review: external audit recommended shipping Phase‑15 with PHI enabled by default to minimize backend divergence and simplify documentation.
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- Maintained parity: PyVM and LLVM continue to share the same MIR stream; PHI nodes remain the single source of truth for join semantics.
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Operational Rules (PHI‑on)
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- Merge blocks place PHIs first, with one incoming per predecessor, covering loop latches, break/continue exits, and structured control flow.
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- `verify_allow_no_phi()` mirrors `NYASH_MIR_NO_PHI`; with PHI‑on it stays strict and fails if SSA form is missing.
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- Use `NYASH_LLVM_TRACE_PHI=1` to inspect wiring; traces now confirm the builder’s SSA layout instead of synthesizing it from edge copies.
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Fallback Mode (PHI‑off)
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- Toggle: `NYASH_MIR_NO_PHI=1` (optionally pair with `NYASH_VERIFY_ALLOW_NO_PHI=1`).
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- Behavior: MIR builders revert to edge copies per predecessor and skip PHI emission. This path is retained only for diagnosing older JSON dumps.
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- Guardrails: tooling should mark PHI‑off runs as legacy; new smokes and CI stay on PHI‑on unless explicitly overridden.
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Backends
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- LLVM harness consumes the PHI‑rich MIR stream and validates incoming edges; no extra synthesis is performed unless legacy mode is forced.
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- Cranelift/JIT paths operate on the same MIR14 form; Phase‑15 keeps them secondary but expects PHIs to be present.
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Acceptance
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- Default smokes/CI run with PHI‑on.
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- Legacy PHI‑off runs must document the reason in `CURRENT_TASK.md` (e.g., reproducing historical MIR13 bugs) and avoid committing the override into shared scripts.
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