71 lines
2.7 KiB
Rust
71 lines
2.7 KiB
Rust
//! Match/expr-block lowering for JSON v0 bridge.
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use super::merge::new_block;
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use super::BridgeEnv;
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use crate::mir::{BasicBlockId, CompareOp, ConstValue, MirFunction, MirInstruction, ValueId};
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use super::super::ast::{ExprV0, MatchArmV0};
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use super::expr::{lower_expr_with_scope, VarScope};
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pub(super) fn lower_match_expr_with_scope<S: VarScope>(
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env: &BridgeEnv,
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f: &mut MirFunction,
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cur_bb: BasicBlockId,
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scrutinee: &ExprV0,
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arms: &[MatchArmV0],
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else_expr: &ExprV0,
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vars: &mut S,
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) -> Result<(ValueId, BasicBlockId), String> {
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// Evaluate scrutinee
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let (scr_val, start_bb) = lower_expr_with_scope(env, f, cur_bb, scrutinee, vars)?;
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// Set up blocks
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let dispatch_bb = new_block(f);
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if let Some(bb) = f.get_block_mut(start_bb) {
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if !bb.is_terminated() { crate::mir::ssot::cf_common::set_jump(f, start_bb, dispatch_bb); }
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}
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let else_bb = new_block(f);
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let merge_bb = new_block(f);
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// Chain dispatch over arms
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let mut cur_dispatch = dispatch_bb;
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let mut phi_inputs: Vec<(BasicBlockId, ValueId)> = Vec::new();
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for (i, arm) in arms.iter().enumerate() {
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let then_bb = new_block(f);
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let next_dispatch = if i + 1 < arms.len() { Some(new_block(f)) } else { None };
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let fall_bb = next_dispatch.unwrap_or(else_bb);
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// Pre-allocate ids to avoid double borrow
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let ldst = f.next_value_id();
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let cond = f.next_value_id();
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if let Some(bb) = f.get_block_mut(cur_dispatch) {
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// compare scr_val == label
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bb.add_instruction(MirInstruction::Const { dst: ldst, value: ConstValue::String(arm.label.clone()) });
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}
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crate::mir::ssot::cf_common::emit_compare_func(f, cur_dispatch, cond, CompareOp::Eq, scr_val, ldst);
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crate::mir::ssot::cf_common::set_branch(f, cur_dispatch, cond, then_bb, fall_bb);
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// Then arm body
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let (tval, tend) = lower_expr_with_scope(env, f, then_bb, &arm.expr, vars)?;
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if let Some(bb) = f.get_block_mut(tend) {
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if !bb.is_terminated() { crate::mir::ssot::cf_common::set_jump(f, tend, merge_bb); }
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}
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phi_inputs.push((tend, tval));
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cur_dispatch = fall_bb;
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}
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// Else body
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let (eval, eend) = lower_expr_with_scope(env, f, else_bb, else_expr, vars)?;
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if let Some(bb) = f.get_block_mut(eend) {
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if !bb.is_terminated() { crate::mir::ssot::cf_common::set_jump(f, eend, merge_bb); }
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}
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phi_inputs.push((eend, eval));
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// Merge result
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let out = f.next_value_id();
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// フェーズM.2: PHI統一処理（no_phi分岐削除）
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let inputs = phi_inputs;
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crate::mir::ssot::cf_common::insert_phi_at_head(f, merge_bb, out, inputs);
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Ok((out, merge_bb))
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}
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