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Jon Ross-Perkins
43065a1257
This adds a distinction between Unused and SoloParseNode, rather than equating the two. This is intended to help identify nodes which are getting pushed but maybe don't need to be. Not totally done because I want to adjust declaration name handling due to a quirk with how it mixes Name with Expression, but almost done. Once that's done the type punning will be completely gone.
84 lines
3.2 KiB
C++
84 lines
3.2 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 {
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auto SemanticsHandleExpressionStatement(SemanticsContext& context,
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ParseTree::Node /*parse_node*/)
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-> bool {
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// Pop the expression without investigating its contents.
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// TODO: This will probably eventually need to do some "do not discard"
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// analysis.
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context.node_stack().PopExpression();
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return true;
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}
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auto SemanticsHandleReturnStatement(SemanticsContext& context,
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ParseTree::Node parse_node) -> bool {
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CARBON_CHECK(!context.return_scope_stack().empty());
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const auto& fn_node =
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context.semantics_ir().GetNode(context.return_scope_stack().back());
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const auto& callable =
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context.semantics_ir().GetFunction(fn_node.GetAsFunctionDeclaration());
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if (context.parse_tree().node_kind(context.node_stack().PeekParseNode()) ==
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ParseNodeKind::ReturnStatementStart) {
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context.node_stack()
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.PopAndDiscardSoloParseNode<ParseNodeKind::ReturnStatementStart>();
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if (callable.return_type_id.is_valid()) {
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// TODO: Add a note pointing at the return type's parse node.
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CARBON_DIAGNOSTIC(ReturnStatementMissingExpression, Error,
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"Must return a {0}.", std::string);
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context.emitter()
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.Build(parse_node, ReturnStatementMissingExpression,
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context.semantics_ir().StringifyType(callable.return_type_id))
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.Emit();
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}
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context.AddNode(SemanticsNode::Return::Make(parse_node));
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} else {
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auto arg = context.node_stack().PopExpression();
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context.node_stack()
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.PopAndDiscardSoloParseNode<ParseNodeKind::ReturnStatementStart>();
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if (!callable.return_type_id.is_valid()) {
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CARBON_DIAGNOSTIC(
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ReturnStatementDisallowExpression, Error,
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"No return expression should be provided in this context.");
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CARBON_DIAGNOSTIC(ReturnStatementImplicitNote, Note,
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"There was no return type provided.");
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context.emitter()
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.Build(parse_node, ReturnStatementDisallowExpression)
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.Note(fn_node.parse_node(), ReturnStatementImplicitNote)
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.Emit();
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} else {
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arg =
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context.ImplicitAsRequired(parse_node, arg, callable.return_type_id);
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}
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context.AddNode(SemanticsNode::ReturnExpression::Make(
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parse_node, context.semantics_ir().GetNode(arg).type_id(), arg));
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}
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// Switch to a new, unreachable, empty node block. This typically won't
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// contain any semantics IR, but it can do if there are statements following
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// the `return` statement.
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context.node_block_stack().Pop();
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context.node_block_stack().PushUnreachable();
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return true;
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}
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auto SemanticsHandleReturnStatementStart(SemanticsContext& context,
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ParseTree::Node parse_node) -> bool {
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// No action, just a bracketing node.
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context.node_stack().Push(parse_node);
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return true;
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}
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} // namespace Carbon
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