diff options
| -rw-r--r-- | src/mir/from_hir.cpp | 80 | ||||
| -rw-r--r-- | src/mir/from_hir.hpp | 5 | ||||
| -rw-r--r-- | src/mir/mir_builder.cpp | 4 |
3 files changed, 69 insertions, 20 deletions
diff --git a/src/mir/from_hir.cpp b/src/mir/from_hir.cpp index 0f200d31..fe876686 100644 --- a/src/mir/from_hir.cpp +++ b/src/mir/from_hir.cpp @@ -21,6 +21,26 @@ namespace { + template<typename T> + struct SaveAndEditVal { + T& m_dst; + T m_saved; + SaveAndEditVal(T& dst, T newval): + m_dst(dst), + m_saved(dst) + { + m_dst = mv$(newval); + } + ~SaveAndEditVal() + { + this->m_dst = this->m_saved; + } + }; + template<typename T> + SaveAndEditVal<T> save_and_edit(T& dst, typename ::std::remove_reference<T&>::type newval) { + return SaveAndEditVal<T> { dst, mv$(newval) }; + } + class ExprVisitor_Conv: public MirConverter { @@ -36,6 +56,9 @@ namespace { }; ::std::vector<LoopDesc> m_loop_stack; + const ScopeHandle* m_block_tmp_scope = nullptr; + const ScopeHandle* m_borrow_raise_target = nullptr; + public: ExprVisitor_Conv(MirBuilder& builder, const ::std::vector< ::HIR::TypeRef>& var_types): m_builder(builder), @@ -153,11 +176,22 @@ namespace { m_builder.push_stmt_assign( sp, ::MIR::LValue::make_Variable(pat.m_binding.m_slot), mv$(lval) ); break; case ::HIR::PatternBinding::Type::Ref: + if(m_borrow_raise_target) + { + DEBUG("- Raising destructure borrow of " << lval << " to scope " << *m_borrow_raise_target); + m_builder.raise_variables(sp, lval, *m_borrow_raise_target); + } + m_builder.push_stmt_assign( sp, ::MIR::LValue::make_Variable(pat.m_binding.m_slot), ::MIR::RValue::make_Borrow({ 0, ::HIR::BorrowType::Shared, mv$(lval) }) ); break; case ::HIR::PatternBinding::Type::MutRef: + if(m_borrow_raise_target) + { + DEBUG("- Raising destructure borrow of " << lval << " to scope " << *m_borrow_raise_target); + m_builder.raise_variables(sp, lval, *m_borrow_raise_target); + } m_builder.push_stmt_assign( sp, ::MIR::LValue::make_Variable(pat.m_binding.m_slot), ::MIR::RValue::make_Borrow({ 0, ::HIR::BorrowType::Unique, mv$(lval) }) ); @@ -376,26 +410,15 @@ namespace { auto res_val = (node.m_yields_final ? m_builder.new_temporary(node.m_res_type) : ::MIR::LValue()); auto tmp_scope = m_builder.new_scope_temp(node.span()); + auto _block_tmp_scope = save_and_edit(m_block_tmp_scope, &tmp_scope); auto scope = m_builder.new_scope_var(node.span()); for(unsigned int i = 0; i < node.m_nodes.size() - (node.m_yields_final ? 1 : 0); i ++) { + auto _ = save_and_edit(m_borrow_raise_target, nullptr); auto& subnode = node.m_nodes[i]; const Span& sp = subnode->span(); - // Let statements don't generate a new temporary scope - if( dynamic_cast<::HIR::ExprNode_Let*>(subnode.get()) ) { - this->visit_node_ptr(subnode); - if( ! m_builder.block_active() ) { - m_builder.set_cur_block( m_builder.new_bb_unlinked() ); - diverged = true; - } - else { - m_builder.get_result(sp); - } - continue ; - } - auto stmt_scope = m_builder.new_scope_temp(sp); this->visit_node_ptr(subnode); @@ -495,23 +518,35 @@ namespace { } void visit(::HIR::ExprNode_Let& node) override { - TRACE_FUNCTION_F("_Let"); + TRACE_FUNCTION_F("_Let " << node.m_pattern); this->define_vars_from(node.span(), node.m_pattern); if( node.m_value ) { + auto _ = save_and_edit(m_borrow_raise_target, m_block_tmp_scope); this->visit_node_ptr(node.m_value); if( ! m_builder.block_active() ) { return ; } + auto res = m_builder.get_result(node.span()); + + // NOTE: `let foo = &bar();` is valid! + // - So is `let (ref foo, _) = (bar(), 1);` + // - Raising the variables if there's a borrow works for most + // cases, but not cases where the let causes an unsizing. + if( res.is_Borrow() ) + { + assert(m_block_tmp_scope); + m_builder.raise_variables(node.span(), res, *m_block_tmp_scope); + } if( node.m_pattern.m_binding.is_valid() && node.m_pattern.m_data.is_Any() && node.m_pattern.m_binding.m_type == ::HIR::PatternBinding::Type::Move ) { - m_builder.push_stmt_assign( node.span(), ::MIR::LValue::make_Variable(node.m_pattern.m_binding.m_slot), m_builder.get_result(node.span()) ); + m_builder.push_stmt_assign( node.span(), ::MIR::LValue::make_Variable(node.m_pattern.m_binding.m_slot), mv$(res) ); } else { - this->destructure_from(node.span(), node.m_pattern, m_builder.get_result_in_lvalue(node.m_value->span(), node.m_type)); + this->destructure_from(node.span(), node.m_pattern, m_builder.lvalue_or_temp(node.m_value->span(), node.m_type, mv$(res))); } } m_builder.set_result(node.span(), ::MIR::RValue::make_Tuple({})); @@ -597,6 +632,7 @@ namespace { void visit(::HIR::ExprNode_Match& node) override { TRACE_FUNCTION_FR("_Match", "_Match"); + auto _ = save_and_edit(m_borrow_raise_target, nullptr); this->visit_node_ptr(node.m_value); auto stmt_scope = m_builder.new_scope_temp(node.span()); auto match_val = m_builder.get_result_in_lvalue(node.m_value->span(), node.m_value->m_res_type); @@ -1119,9 +1155,13 @@ namespace { this->visit_node_ptr(node.m_value); auto val = m_builder.get_result_in_lvalue(node.m_value->span(), ty_val); - auto res = m_builder.new_temporary(node.m_res_type); - m_builder.push_stmt_assign( node.span(), res.as_Temporary(), ::MIR::RValue::make_Borrow({ 0, node.m_type, mv$(val) })); - m_builder.set_result( node.span(), mv$(res) ); + if( m_borrow_raise_target ) + { + DEBUG("- Raising borrow to scope " << *m_borrow_raise_target); + m_builder.raise_variables(node.span(), val, *m_borrow_raise_target); + } + + m_builder.set_result( node.span(), ::MIR::RValue::make_Borrow({ 0, node.m_type, mv$(val) }) ); } void visit(::HIR::ExprNode_Cast& node) override { @@ -1603,6 +1643,7 @@ namespace { void visit(::HIR::ExprNode_CallPath& node) override { TRACE_FUNCTION_F("_CallPath " << node.m_path); + auto _ = save_and_edit(m_borrow_raise_target, nullptr); auto values = get_args(node.m_args); auto panic_block = m_builder.new_bb_unlinked(); @@ -1670,6 +1711,7 @@ namespace { void visit(::HIR::ExprNode_CallValue& node) override { TRACE_FUNCTION_F("_CallValue " << node.m_value->m_res_type); + auto _ = save_and_edit(m_borrow_raise_target, nullptr); // _CallValue is ONLY valid on function pointers (all others must be desugared) ASSERT_BUG(node.span(), node.m_value->m_res_type.m_data.is_Function(), "Leftover _CallValue on a non-fn()"); diff --git a/src/mir/from_hir.hpp b/src/mir/from_hir.hpp index c8d34151..9ee7b733 100644 --- a/src/mir/from_hir.hpp +++ b/src/mir/from_hir.hpp @@ -36,6 +36,11 @@ public: ScopeHandle& operator=(const ScopeHandle& x) = delete; ScopeHandle& operator=(ScopeHandle&& x) = delete; ~ScopeHandle(); + + friend ::std::ostream& operator<<(::std::ostream& os, const ScopeHandle& x) { + os << x.idx; + return os; + } }; // - Needs to handle future DerefMove (which can't use the Box hack) diff --git a/src/mir/mir_builder.cpp b/src/mir/mir_builder.cpp index 987eb267..54dbc5e7 100644 --- a/src/mir/mir_builder.cpp +++ b/src/mir/mir_builder.cpp @@ -407,6 +407,8 @@ void MirBuilder::raise_variables(const Span& sp, const ::MIR::LValue& val, const TRACE_FUNCTION_F(val); TU_MATCH_DEF(::MIR::LValue, (val), (e), ( + // No raising of these source values + return ; ), // TODO: This may not be correct, because it can change the drop points and ordering // HACK: Working around cases where values are dropped while the result is not yet used. @@ -428,7 +430,7 @@ void MirBuilder::raise_variables(const Span& sp, const ::MIR::LValue& val, const (Temporary, ) ) - ASSERT_BUG(sp, val.is_Variable() || val.is_Temporary(), ""); + ASSERT_BUG(sp, val.is_Variable() || val.is_Temporary(), "Hit value raising code with non-variable value - " << val); auto scope_it = m_scope_stack.rbegin(); while( scope_it != m_scope_stack.rend() ) |