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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
3.0 KiB
C++
85 lines
3.0 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 HandleIfConditionStart(Context& /*context*/,
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ParseTree::Node /*parse_node*/) -> bool {
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return true;
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}
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auto HandleIfCondition(Context& context, ParseTree::Node parse_node) -> bool {
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// Convert the condition to `bool`.
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auto cond_value_id = context.node_stack().PopExpression();
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cond_value_id = context.ConvertToBoolValue(parse_node, cond_value_id);
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// Create the then block and the else block, and branch to the right one. If
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// there is no `else`, the then block will terminate with a branch to the
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// else block, which will be reused as the resumption block.
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auto then_block_id =
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context.AddDominatedBlockAndBranchIf(parse_node, cond_value_id);
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auto else_block_id = context.AddDominatedBlockAndBranch(parse_node);
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// Push the else and then blocks, and start emitting code in the then block.
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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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context.node_stack().Push(parse_node);
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return true;
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}
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auto HandleIfStatementElse(Context& context, ParseTree::Node parse_node)
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-> bool {
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context.node_stack().PopAndDiscardSoloParseNode<ParseNodeKind::IfCondition>();
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// Switch to emitting the else block.
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auto then_block_id = context.node_block_stack().PopForAdd();
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context.node_stack().Push(parse_node, then_block_id);
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context.AddCurrentCodeBlockToFunction();
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return true;
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}
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auto HandleIfStatement(Context& context, ParseTree::Node parse_node) -> bool {
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// Either the then or else block, depending on whether there's an `else` node
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// on the top of the node stack.
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auto sub_block_id = context.node_block_stack().PopForAdd();
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switch (auto kind = context.parse_tree().node_kind(
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context.node_stack().PeekParseNode())) {
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case ParseNodeKind::IfCondition: {
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// Branch from then block to else block.
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context.node_stack()
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.PopAndDiscardSoloParseNode<ParseNodeKind::IfCondition>();
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context.AddNodeToBlock(
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sub_block_id,
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SemIR::Node::Branch::Make(parse_node,
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context.node_block_stack().PeekForAdd()));
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break;
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}
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case ParseNodeKind::IfStatementElse: {
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// Branch from the then and else blocks to a new resumption block.
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SemIR::NodeBlockId then_block_id =
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context.node_stack().Pop<ParseNodeKind::IfStatementElse>();
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context.AddConvergenceBlockAndPush(parse_node,
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{then_block_id, sub_block_id});
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break;
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}
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default: {
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CARBON_FATAL() << "Unexpected parse node at start of `if`: " << kind;
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}
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}
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context.AddCurrentCodeBlockToFunction();
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return true;
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}
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} // namespace Carbon::Check
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