hakorune/src/mir/join_ir/lowering/mod.rs

//! JoinIR Lowering Functions
//!
//! Phase 27.9: Modular separation of MIR → JoinIR lowering implementations.
//!
//! このモジュールは各種 MIR 関数を JoinIR に変換する lowering 関数を提供します。
//!
//! ## 構成:
//! - `common.rs`: CFG sanity checks と lowering 共通ユーティリティ（Phase 27.10）
//! - `value_id_ranges.rs`: ValueId 範囲管理（Phase 27.13+）
//! - `min_loop.rs`: JoinIrMin.main/0 専用の最小ループ lowering
//! - `skip_ws.rs`: Main.skip/1 の空白スキップ lowering（手書き版＋MIR自動解析版）
//! - `funcscanner_trim.rs`: FuncScannerBox.trim/1 の trim lowering
//! - `stage1_using_resolver.rs`: Stage1UsingResolverBox.resolve_for_source entries loop lowering（Phase 27.12）
//! - `funcscanner_append_defs.rs`: FuncScannerBox._append_defs/2 の配列結合 lowering（Phase 27.14）
//! - `if_select.rs`: Phase 33 If/Else → Select lowering

pub mod common;
pub mod exit_args_resolver;
pub mod funcscanner_append_defs;
pub mod funcscanner_trim;
pub mod generic_case_a;
pub mod if_select; // Phase 33
pub mod loop_form_intake;
pub mod loop_scope_shape;
pub mod loop_to_join;
pub mod min_loop;
pub mod skip_ws;
pub mod stage1_using_resolver;
pub mod stageb_body;
pub mod stageb_funcscanner;
pub mod value_id_ranges;

// Re-export public lowering functions
pub use funcscanner_append_defs::lower_funcscanner_append_defs_to_joinir;
pub use funcscanner_trim::lower_funcscanner_trim_to_joinir;
// Phase 31: LoopToJoinLowerer 統一箱
pub use loop_to_join::LoopToJoinLowerer;
// Phase 30 F-3: 旧 lower_case_a_loop_to_joinir_for_minimal_skip_ws は _with_scope に置き換え済みのため削除
pub use min_loop::lower_min_loop_to_joinir;
pub use skip_ws::lower_skip_ws_to_joinir;
pub use stage1_using_resolver::lower_stage1_usingresolver_to_joinir;
pub use stageb_body::lower_stageb_body_to_joinir;
pub use stageb_funcscanner::lower_stageb_funcscanner_to_joinir;

// Phase 33: If/Else → Select lowering entry point
use crate::mir::join_ir::JoinInst;
use crate::mir::{BasicBlockId, MirFunction};

/// Phase 33-3: Try to lower if/else to JoinIR Select instruction
///
/// Scope:
/// - Only applies to whitelisted functions:
///   - IfSelectTest.* (Phase 33-2/33-3)
///   - JsonShapeParser._read_value_from_pair/1 (Phase 33-4 Stage-1)
///   - Stage1JsonScannerBox.value_start_after_key_pos/2 (Phase 33-4 Stage-B)
/// - Requires NYASH_JOINIR_IF_SELECT=1 environment variable
/// - Falls back to traditional if_phi on pattern mismatch
///
/// Returns Some(JoinInst::Select) if pattern matched, None otherwise.
pub fn try_lower_if_to_joinir(
    func: &MirFunction,
    block_id: BasicBlockId,
    debug: bool,
) -> Option<JoinInst> {
    // dev トグルチェック
    if !crate::config::env::joinir_if_select_enabled() {
        return None;
    }

    // Phase 33-4: 関数名ガード拡張（IfSelectTest + Stage-1/Stage-B 候補）
    let is_allowed = func.signature.name.starts_with("IfSelectTest.")
        || func.signature.name == "JsonShapeParser._read_value_from_pair/1"
        || func.signature.name == "Stage1JsonScannerBox.value_start_after_key_pos/2";

    if !is_allowed {
        if debug {
            eprintln!(
                "[try_lower_if_to_joinir] skipping non-allowed function: {}",
                func.signature.name
            );
        }
        return None;
    }

    // if_select lowering を試行
    let lowerer = if_select::IfSelectLowerer::new(debug);

    if !lowerer.can_lower_to_select(func, block_id) {
        if debug {
            eprintln!(
                "[try_lower_if_to_joinir] pattern not matched for {}",
                func.signature.name
            );
        }
        return None;
    }

    let result = lowerer.lower_if_to_select(func, block_id);

    if result.is_some() && debug {
        eprintln!(
            "[try_lower_if_to_joinir] if_select lowering used for {}",
            func.signature.name
        );
    }

    result
}