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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.
65 lines
2.6 KiB
C++
65 lines
2.6 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 SemanticsHandleIfExpressionIf(SemanticsContext& context,
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ParseTree::Node if_node) -> bool {
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auto cond_value_id = context.node_stack().Pop<SemanticsNodeId>();
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context.node_stack().Push(if_node);
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// Convert the condition to `bool`, and branch on it.
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cond_value_id = context.ImplicitAsBool(if_node, cond_value_id);
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auto then_block_id =
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context.AddDominatedBlockAndBranchIf(if_node, cond_value_id);
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auto else_block_id = context.AddDominatedBlockAndBranch(if_node);
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// Push the `else` block and `then` block, and start emitting the `then`.
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context.node_block_stack().Pop();
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context.node_block_stack().Push(else_block_id);
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context.node_block_stack().Push(then_block_id);
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context.AddCurrentCodeBlockToFunction();
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return true;
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}
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auto SemanticsHandleIfExpressionThen(SemanticsContext& context,
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ParseTree::Node then_node) -> bool {
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context.node_stack().Push(then_node, context.node_block_stack().Pop());
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context.AddCurrentCodeBlockToFunction();
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return true;
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}
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auto SemanticsHandleIfExpressionElse(SemanticsContext& context,
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ParseTree::Node else_node) -> bool {
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auto else_value_id = context.node_stack().Pop<SemanticsNodeId>();
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auto [then_node, then_end_block_id] =
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context.node_stack().PopWithParseNode<ParseNodeKind::IfExpressionThen>();
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auto then_value_id = context.node_stack().Pop<SemanticsNodeId>();
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auto if_node =
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context.node_stack().PopForSoloParseNode<ParseNodeKind::IfExpressionIf>();
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// Convert the `else` value to the `then` value's type, and finish the `else`
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// block.
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// TODO: Find a common type, and convert both operands to it instead.
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auto result_type_id = context.semantics_ir().GetNode(then_value_id).type_id();
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else_value_id =
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context.ImplicitAsRequired(else_node, else_value_id, result_type_id);
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auto else_end_block_id = context.node_block_stack().Pop();
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// Create a resumption block and branches to it.
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auto chosen_value_id = context.AddConvergenceBlockWithArgAndPush(
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if_node,
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{{then_end_block_id, then_value_id}, {else_end_block_id, else_value_id}});
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context.AddCurrentCodeBlockToFunction();
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// Push the result value.
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context.node_stack().Push(else_node, chosen_value_id);
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return true;
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}
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} // namespace Carbon
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