Files
carbon-lang/toolchain/check/handle_if_statement.cpp
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Jon Ross-Perkins 1c748c0f14 Split semantics into check and sem_ir directories (#3176)
Continuing along with #3070. Note this is just a file rename, with BUILD
edits; every file previously in semantics/ should show as moved (except
maybe BUILDs, which split).
2023-08-31 19:54:32 +00:00

85 lines
3.0 KiB
C++

// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
// Exceptions. See /LICENSE for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
#include "toolchain/check/context.h"
#include "toolchain/sem_ir/node.h"
namespace Carbon::Check {
auto HandleIfConditionStart(Context& /*context*/, Parse::Node /*parse_node*/)
-> bool {
return true;
}
auto HandleIfCondition(Context& context, Parse::Node parse_node) -> bool {
// Convert the condition to `bool`.
auto cond_value_id = context.node_stack().PopExpression();
cond_value_id = context.ConvertToBoolValue(parse_node, cond_value_id);
// Create the then block and the else block, and branch to the right one. If
// there is no `else`, the then block will terminate with a branch to the
// else block, which will be reused as the resumption block.
auto then_block_id =
context.AddDominatedBlockAndBranchIf(parse_node, cond_value_id);
auto else_block_id = context.AddDominatedBlockAndBranch(parse_node);
// Push the else and then blocks, and start emitting code in the then block.
context.node_block_stack().Pop();
context.node_block_stack().Push(else_block_id);
context.node_block_stack().Push(then_block_id);
context.AddCurrentCodeBlockToFunction();
context.node_stack().Push(parse_node);
return true;
}
auto HandleIfStatementElse(Context& context, Parse::Node parse_node) -> bool {
context.node_stack()
.PopAndDiscardSoloParseNode<Parse::NodeKind::IfCondition>();
// Switch to emitting the else block.
auto then_block_id = context.node_block_stack().PopForAdd();
context.node_stack().Push(parse_node, then_block_id);
context.AddCurrentCodeBlockToFunction();
return true;
}
auto HandleIfStatement(Context& context, Parse::Node parse_node) -> bool {
// Either the then or else block, depending on whether there's an `else` node
// on the top of the node stack.
auto sub_block_id = context.node_block_stack().PopForAdd();
switch (auto kind = context.parse_tree().node_kind(
context.node_stack().PeekParseNode())) {
case Parse::NodeKind::IfCondition: {
// Branch from then block to else block.
context.node_stack()
.PopAndDiscardSoloParseNode<Parse::NodeKind::IfCondition>();
context.AddNodeToBlock(
sub_block_id,
SemIR::Node::Branch::Make(parse_node,
context.node_block_stack().PeekForAdd()));
break;
}
case Parse::NodeKind::IfStatementElse: {
// Branch from the then and else blocks to a new resumption block.
SemIR::NodeBlockId then_block_id =
context.node_stack().Pop<Parse::NodeKind::IfStatementElse>();
context.AddConvergenceBlockAndPush(parse_node,
{then_block_id, sub_block_id});
break;
}
default: {
CARBON_FATAL() << "Unexpected parse node at start of `if`: " << kind;
}
}
context.AddCurrentCodeBlockToFunction();
return true;
}
} // namespace Carbon::Check