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Richard SmithandChandler Carruth
1013d1773c
Start treating function calls as initializing expressions instead of as value expressions. This required adding support for expression categories. Value bindings and temporary materialization conversions are created where necessary to transition between expression categories. For a function call with a return slot, we speculatively create a materialized temporary before the call and either commit to it or replace it with something else later, once we see how the function call expression is actually used. This change follows the direction suggested in #3133 for initializing expressions: depending on the return type of a function, the return value will either be initialized in-place or returned directly. This is visible in the semantics IR, which is a little unfortunate but is probably necessary as this is part of the semantics of the program. --------- Co-authored-by: Chandler Carruth <chandlerc@gmail.com>
85 lines
3.1 KiB
C++
85 lines
3.1 KiB
C++
// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
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// Exceptions. See /LICENSE for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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#include "toolchain/semantics/semantics_context.h"
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#include "toolchain/semantics/semantics_node.h"
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namespace Carbon::Check {
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auto HandleCallExpression(Context& context, ParseTree::Node parse_node)
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-> bool {
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auto refs_id = context.ParamOrArgEnd(
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/*for_args=*/true, ParseNodeKind::CallExpressionStart);
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// TODO: Convert to call expression.
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auto [call_expr_parse_node, name_id] =
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context.node_stack()
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.PopWithParseNode<ParseNodeKind::CallExpressionStart>();
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auto name_node = context.semantics_ir().GetNode(name_id);
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if (name_node.kind() != SemIR::NodeKind::FunctionDeclaration) {
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// TODO: Work on error.
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context.TODO(parse_node, "Not a callable name");
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context.node_stack().Push(parse_node, name_id);
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return true;
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}
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auto function_id = name_node.GetAsFunctionDeclaration();
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const auto& callable = context.semantics_ir().GetFunction(function_id);
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CARBON_DIAGNOSTIC(NoMatchingCall, Error, "No matching callable was found.");
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auto diagnostic =
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context.emitter().Build(call_expr_parse_node, NoMatchingCall);
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if (!context.ImplicitAsForArgs(refs_id, name_node.parse_node(),
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callable.param_refs_id, &diagnostic)) {
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diagnostic.Emit();
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context.node_stack().Push(parse_node, SemIR::NodeId::BuiltinError);
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return true;
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}
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CARBON_CHECK(context.ImplicitAsForArgs(refs_id, name_node.parse_node(),
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callable.param_refs_id,
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/*diagnostic=*/nullptr));
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// For functions with an implicit return type, the return type is the empty
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// tuple type.
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SemIR::TypeId type_id = callable.return_type_id;
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if (!type_id.is_valid()) {
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type_id = context.CanonicalizeTupleType(call_expr_parse_node, {});
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}
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// If there is a return slot, add a corresponding argument.
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if (callable.return_slot_id.is_valid()) {
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if (refs_id == SemIR::NodeBlockId::Empty) {
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refs_id = context.semantics_ir().AddNodeBlock();
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}
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// Tentatively put a materialized temporary in the function's return slot.
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// This will be replaced if necessary when we perform initialization.
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auto return_slot_id =
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context.AddNode(SemIR::Node::MaterializeTemporary::Make(
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call_expr_parse_node, callable.return_type_id));
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context.semantics_ir().GetNodeBlock(refs_id).push_back(return_slot_id);
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}
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auto call_node_id = context.AddNode(SemIR::Node::Call::Make(
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call_expr_parse_node, type_id, refs_id, function_id));
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context.node_stack().Push(parse_node, call_node_id);
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return true;
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}
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auto HandleCallExpressionComma(Context& context, ParseTree::Node /*parse_node*/)
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-> bool {
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context.ParamOrArgComma(/*for_args=*/true);
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return true;
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}
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auto HandleCallExpressionStart(Context& context, ParseTree::Node parse_node)
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-> bool {
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auto name_id = context.node_stack().PopExpression();
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context.node_stack().Push(parse_node, name_id);
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context.ParamOrArgStart();
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return true;
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}
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} // namespace Carbon::Check
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