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Jon Ross-Perkins
9751b4701d
I think there's more we can do here, but this seemed like a good checkpoint to make sure the path I'm going down is roughly what you expected. There's one actual edit in if expression structure to match the increased enforcement.
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().PopAndDiscardId();
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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().Pop<SemanticsNodeId>();
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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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