diff options
| -rw-r--r-- | src/mir/from_hir_match.cpp | 99 |
1 files changed, 90 insertions, 9 deletions
diff --git a/src/mir/from_hir_match.cpp b/src/mir/from_hir_match.cpp index f5607926..5c3e945e 100644 --- a/src/mir/from_hir_match.cpp +++ b/src/mir/from_hir_match.cpp @@ -1432,6 +1432,14 @@ struct DecisionTreeGen const ::HIR::TypeRef& ty, ::MIR::LValue val, ::std::function<void(const DecisionTreeNode&)> and_then ); + void generate_branches_Slice( + const Span& sp, + const DecisionTreeNode::Branch& default_branch, + const DecisionTreeNode::Values::Data_Slice& branches, + const PatternRule::field_path_t& field_path, + const ::HIR::TypeRef& ty, ::MIR::LValue val, + ::std::function<void(const DecisionTreeNode&)> and_then + ); void generate_tree_code__enum( const Span& sp, const DecisionTreeNode& node, const ::HIR::TypeRef& fake_ty, const ::MIR::LValue& val, @@ -2411,11 +2419,11 @@ void DecisionTreeGen::get_ty_and_val( BUG(sp, "Destructuring a trait object - " << *cur_ty); ), (Array, - // TODO: Slice patterns, sequential comparison/sub-match - TODO(sp, "Match over array"); + assert(idx < e.size_val); + cur_ty = &*e.inner; ), (Slice, - BUG(sp, "Hit match over `[T]` - must be `&[T]`"); + cur_ty = &*e.inner; ), (Borrow, ASSERT_BUG(sp, idx == FIELD_DEREF, "Destructure of borrow doesn't correspond to a deref in the path"); @@ -2546,14 +2554,11 @@ void DecisionTreeGen::generate_tree_code( TODO(sp, "Match over array"); ), (Slice, - // TODO: Slice patterns, sequential comparison/sub-match - TODO(sp, "Match over `[T]`"); - - //ASSERT_BUG(sp, node.m_branches.is_Slice(), "Tree for [T] isn't a _Slice - node="<<node); - //this->generate_branches_Slice(sp, node.m_default, node.m_branches.as_Slice(), ty, mv$(val), mv$(and_then)); + ASSERT_BUG(sp, node.m_branches.is_Slice(), "Tree for [T] isn't a _Slice - node="<<node); + this->generate_branches_Slice(sp, node.m_default, node.m_branches.as_Slice(), node.m_field_path, ty, mv$(val), mv$(and_then)); ), (Borrow, - if( e.inner == ::HIR::CoreType::Str ) { + if( *e.inner == ::HIR::CoreType::Str ) { TODO(sp, "Match over &str"); } else { @@ -2959,6 +2964,82 @@ void DecisionTreeGen::generate_branches_Enum( } } +void DecisionTreeGen::generate_branches_Slice( + const Span& sp, + const DecisionTreeNode::Branch& default_branch, + const DecisionTreeNode::Values::Data_Slice& branches, + const PatternRule::field_path_t& field_path, + const ::HIR::TypeRef& ty, ::MIR::LValue val, + ::std::function<void(const DecisionTreeNode&)> and_then + ) +{ + if( default_branch.is_Unset() ) { + ERROR(sp, E0000, "Non-exhaustive match over " << ty); + } + + auto any_block = m_builder.new_bb_unlinked(); + + // TODO: Select one of three ways of picking the arm: + // - Integer switch (unimplemented) + // - Binary search + // - Sequential comparisons + + auto val_len = m_builder.lvalue_or_temp(sp, ty, ::MIR::RValue::make_DstMeta({ val.clone() })); + + // TODO: Binary search instead. + for( const auto& branch : branches.fixed_arms ) + { + auto val_des = m_builder.lvalue_or_temp(sp, ty, ::MIR::Constant(static_cast<uint64_t>(branch.first))); + + // Special case - final just does equality + if( &branch == &branches.fixed_arms.back() ) + { + auto val_cmp_eq = m_builder.lvalue_or_temp( sp, ::HIR::TypeRef(::HIR::CoreType::Bool), ::MIR::RValue::make_BinOp({ + val_len.clone(), ::MIR::eBinOp::EQ, mv$(val_des) + }) ); + + auto success_block = m_builder.new_bb_unlinked(); + m_builder.end_block( ::MIR::Terminator::make_If({ mv$(val_cmp_eq), any_block, success_block }) ); + + m_builder.set_cur_block( success_block ); + this->generate_branch(branch.second, and_then); + + m_builder.set_cur_block( any_block ); + } + // TODO: Special case for zero (which can't have a LT) + else + { + auto next_block = m_builder.new_bb_unlinked(); + + auto cmp_gt_block = m_builder.new_bb_unlinked(); + auto val_cmp_lt = m_builder.lvalue_or_temp( sp, ::HIR::TypeRef(::HIR::CoreType::Bool), ::MIR::RValue::make_BinOp({ + val_len.clone(), ::MIR::eBinOp::LT, val_des.clone() + }) ); + m_builder.end_block( ::MIR::Terminator::make_If({ mv$(val_cmp_lt), any_block, cmp_gt_block }) ); + m_builder.set_cur_block( cmp_gt_block ); + auto success_block = m_builder.new_bb_unlinked(); + auto val_cmp_gt = m_builder.lvalue_or_temp( sp, ::HIR::TypeRef(::HIR::CoreType::Bool), ::MIR::RValue::make_BinOp({ + val_len.clone(), ::MIR::eBinOp::GT, mv$(val_des) + }) ); + m_builder.end_block( ::MIR::Terminator::make_If({ mv$(val_cmp_gt), next_block, success_block }) ); + + m_builder.set_cur_block( success_block ); + this->generate_branch(branch.second, and_then); + + m_builder.set_cur_block( next_block ); + } + } + assert( m_builder.block_active() ); + + if( default_branch.is_Unset() ) { + // TODO: Emit error if non-exhaustive + m_builder.end_block( ::MIR::Terminator::make_Diverge({}) ); + } + else { + this->generate_branch(default_branch, and_then); + } +} + namespace { bool path_starts_with(const PatternRule::field_path_t& test, const PatternRule::field_path_t& prefix) { |