diff options
Diffstat (limited to 'src/mir/from_hir_match.cpp')
| -rw-r--r-- | src/mir/from_hir_match.cpp | 80 |
1 files changed, 43 insertions, 37 deletions
diff --git a/src/mir/from_hir_match.cpp b/src/mir/from_hir_match.cpp index d1dbfd4d..26035fab 100644 --- a/src/mir/from_hir_match.cpp +++ b/src/mir/from_hir_match.cpp @@ -49,6 +49,7 @@ struct ArmCode { bool has_condition; ::MIR::BasicBlockId cond_code; // NOTE: Incomplete, requires terminating If ::MIR::LValue cond_lval; + ::std::vector< ::MIR::BasicBlockId> destructures; }; typedef ::std::vector<PatternRuleset> t_arm_rules; @@ -83,7 +84,7 @@ void MIR_LowerHIR_Match( MirBuilder& builder, MirConverter& conv, ::HIR::ExprNod auto first_cmp_block = builder.new_bb_unlinked(); builder.end_block( ::MIR::Terminator::make_Goto(first_cmp_block) ); - auto match_scope = builder.new_scope(node.span()); + auto match_scope = builder.new_scope_split(node.span()); // Map of arm index to ruleset ::std::vector< ArmCode> arm_code; @@ -94,43 +95,32 @@ void MIR_LowerHIR_Match( MirBuilder& builder, MirConverter& conv, ::HIR::ExprNod ArmCode ac; // Register introduced bindings to be dropped on return/diverge within this scope - auto drop_scope = builder.new_scope( arm.m_code->span(), true ); + auto drop_scope = builder.new_scope_var( arm.m_code->span() ); + // - Define variables from the first pattern + conv.define_vars_from(node.span(), arm.m_patterns.front()); unsigned int pat_idx = 0; for( const auto& pat : arm.m_patterns ) { + // - Convert HIR pattern into ruleset auto pat_builder = PatternRulesetBuilder {}; pat_builder.append_from(node.span(), pat, node.m_value->m_res_type); arm_rules.push_back( PatternRuleset { arm_idx, pat_idx, mv$(pat_builder.m_rules) } ); DEBUG("(" << arm_idx << "," << pat_idx << ") " << pat << " ==> [" << arm_rules.back().m_rules << "]"); + // - Emit code to destructure the matched pattern + ac.destructures.push_back( builder.new_bb_unlinked() ); + builder.set_cur_block( ac.destructures.back() ); + conv.destructure_from( arm.m_code->span(), pat, match_val.clone(), true ); + builder.pause_cur_block(); + // NOTE: Paused block resumed upon successful match + pat_idx += 1; } - - // Code - ac.code = builder.new_bb_unlinked(); - builder.set_cur_block( ac.code ); - conv.visit_node_ptr( arm.m_code ); - if( !builder.block_active() && !builder.has_result() ) { - DEBUG("Arm diverged"); - // Nothing need be done, as the block diverged. - // - Drops were handled by the diverging block (if not, the below will panic) - auto _ = mv$(drop_scope); - } - else { - DEBUG("Arm result"); - // - Set result - builder.push_stmt_assign( result_val.clone(), builder.get_result(arm.m_code->span()) ); - // - Drop all non-moved values from this scope - builder.terminate_scope( arm.m_code->span(), mv$(drop_scope) ); - // - Go to the next block - builder.end_block( ::MIR::Terminator::make_Goto(next_block) ); - } // Condition - // NOTE: The condition isn't covered by the drop scope, because the only values that can be used within it are - // Copy (otherwise they'd move out and invalidate on failure). + // NOTE: Lack of drop due to early exit from this arm isn't an issue. All captures must be Copy // - The above is rustc E0008 "cannot bind by-move into a pattern guard" if(arm.m_cond) { @@ -152,6 +142,29 @@ void MIR_LowerHIR_Match( MirBuilder& builder, MirConverter& conv, ::HIR::ExprNod ac.has_condition = false; } + // Code + ac.code = builder.new_bb_unlinked(); + builder.set_cur_block( ac.code ); + conv.visit_node_ptr( arm.m_code ); + if( !builder.block_active() && !builder.has_result() ) { + DEBUG("Arm diverged"); + // Nothing need be done, as the block diverged. + // - Drops were handled by the diverging block (if not, the below will panic) + auto _ = mv$(drop_scope); + builder.end_split_arm( arm.m_code->span(), match_scope, false ); + } + else { + DEBUG("Arm result"); + // - Set result + builder.push_stmt_assign( result_val.clone(), builder.get_result(arm.m_code->span()) ); + // - Drop all non-moved values from this scope + builder.terminate_scope( arm.m_code->span(), mv$(drop_scope) ); + // - Go to the next block + builder.end_block( ::MIR::Terminator::make_Goto(next_block) ); + + builder.end_split_arm( arm.m_code->span(), match_scope, true ); + } + arm_code.push_back( mv$(ac) ); } @@ -192,14 +205,13 @@ void MIR_LowerHIR_Match_Simple( MirBuilder& builder, MirConverter& conv, ::HIR:: for( unsigned int i = 0; i < arm.m_patterns.size(); i ++ ) { const auto& pat_rule = arm_rules[rule_idx]; - const auto& pat = arm.m_patterns[i]; bool is_last_pat = (i+1 == arm.m_patterns.size()); auto next_pattern_bb = (!is_last_pat ? builder.new_bb_unlinked() : next_arm_bb); // 1. Check MIR_LowerHIR_Match_Simple__GeneratePattern(builder, arm.m_code->span(), pat_rule.m_rules.data(), pat_rule.m_rules.size(), node.m_value->m_res_type, match_val, next_pattern_bb); - // 2. Destructure - conv.destructure_from( arm.m_code->span(), pat, match_val.clone(), true ); + builder.end_block( ::MIR::Terminator::make_Goto(arm_code.destructures[i]) ); + builder.set_cur_block( arm_code.destructures[i] ); // - Go to code/condition check if( arm_code.has_condition ) @@ -739,17 +751,11 @@ void MIR_LowerHIR_Match_DecisionTree( MirBuilder& builder, MirConverter& conv, : ::std::vector< ::MIR::BasicBlockId> rule_blocks; for(const auto& rule : arm_rules) { - rule_blocks.push_back( builder.new_bb_unlinked() ); - builder.set_cur_block(rule_blocks.back()); - - const auto& arm = node.m_arms[ rule.arm_idx ]; - const auto& pat = arm.m_patterns[rule.pat_idx]; - - // Assign bindings (drop registration happens in previous loop) - Allow refutable patterns - conv.destructure_from( arm.m_code->span(), pat, match_val.clone(), true ); + const auto& arm_code = arms_code[rule.arm_idx]; + ASSERT_BUG(node.span(), !arm_code.has_condition, "Decision tree doesn't (yet) support conditionals"); - ASSERT_BUG(node.span(), ! arms_code[rule.arm_idx].has_condition, "Decision tree doesn't (yet) support conditionals"); - builder.end_block( ::MIR::Terminator::make_Goto( arms_code[rule.arm_idx].code ) ); + assert( rule.pat_idx < arm_code.destructures.size() ); + rule_blocks.push_back( arm_code.destructures[rule.pat_idx] ); } |