mirror of
https://github.com/carbon-language/carbon-lang.git
synced 2026-09-24 22:02:23 +01:00
Richard Smith
202d3f5993
Add semantic analysis and semantics IR building for `if` expressions, and add the first parts of control flow handling to semantics IR. After discussion with @chandlerc, use [block arguments](https://en.wikipedia.org/wiki/Static_single-assignment_form#Block_arguments) to convey values from the two arms of the `if` to the result. For now, only a single block argument is supported, but we should revisit this as we explore more of the requirements of the Semantics IR form. Functions can now contain multiple code blocks, so grab the entry block up-front instead of assuming the entry block will be at the top of the block stack when we reach the end of function emission. Add trivial support for `bool` type literal, because without it we can't write testcases.
85 lines
3.2 KiB
C++
85 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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namespace Carbon {
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auto SemanticsHandleFunctionDeclaration(SemanticsContext& context,
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ParseTree::Node parse_node) -> bool {
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return context.TODO(parse_node, "HandleFunctionDeclaration");
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}
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auto SemanticsHandleFunctionDefinition(SemanticsContext& context,
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ParseTree::Node /*parse_node*/) -> bool {
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// Merges code block children up under the FunctionDefinitionStart.
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while (context.parse_tree().node_kind(context.node_stack().PeekParseNode()) !=
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ParseNodeKind::FunctionDefinitionStart) {
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context.node_stack().PopAndIgnore();
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}
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context.node_stack().PopAndDiscardId(ParseNodeKind::FunctionDefinitionStart);
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context.return_scope_stack().pop_back();
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context.PopScope();
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context.node_block_stack().Pop();
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return true;
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}
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auto SemanticsHandleFunctionDefinitionStart(SemanticsContext& context,
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ParseTree::Node parse_node)
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-> bool {
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SemanticsTypeId return_type_id = SemanticsTypeId::Invalid;
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if (context.parse_tree().node_kind(context.node_stack().PeekParseNode()) ==
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ParseNodeKind::ReturnType) {
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return_type_id =
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context.node_stack().Pop<SemanticsTypeId>(ParseNodeKind::ReturnType);
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} else {
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// Canonicalize the empty tuple for the implicit return.
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context.CanonicalizeType(SemanticsNodeId::BuiltinEmptyTupleType);
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}
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auto param_refs_id = context.node_stack().Pop<SemanticsNodeBlockId>(
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ParseNodeKind::ParameterList);
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auto name_node =
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context.node_stack().PopForSoloParseNode(ParseNodeKind::DeclaredName);
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auto fn_node = context.node_stack().PopForSoloParseNode(
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ParseNodeKind::FunctionIntroducer);
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auto name_str = context.parse_tree().GetNodeText(name_node);
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auto name_id = context.semantics_ir().AddString(name_str);
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// Create the entry block.
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auto outer_block = context.node_block_stack().PeekForAdd();
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context.node_block_stack().Push();
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// Add the callable.
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auto function_id = context.semantics_ir().AddFunction(
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{.name_id = name_id,
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.param_refs_id = param_refs_id,
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.return_type_id = return_type_id,
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.body_id = context.node_block_stack().PeekForAdd()});
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auto decl_id = context.AddNodeToBlock(
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outer_block,
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SemanticsNode::FunctionDeclaration::Make(fn_node, function_id));
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context.AddNameToLookup(name_node, name_id, decl_id);
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context.PushScope();
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for (auto ref_id : context.semantics_ir().GetNodeBlock(param_refs_id)) {
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auto ref = context.semantics_ir().GetNode(ref_id);
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auto [name_id, target_id] = ref.GetAsBindName();
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context.AddNameToLookup(ref.parse_node(), name_id, target_id);
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}
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context.return_scope_stack().push_back(decl_id);
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context.node_stack().Push(parse_node, function_id);
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return true;
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}
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auto SemanticsHandleFunctionIntroducer(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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