Files
carbon-lang/toolchain/check/handle_if_statement.cpp
T
Richard Smith 0a1abe9f64 Clean up some uses of the node stack. (#3512)
Also minor cleanups for the stack itself.
2023-12-14 20:57:03 +00:00

79 lines
2.7 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/check/convert.h"
#include "toolchain/sem_ir/inst.h"
namespace Carbon::Check {
auto HandleIfConditionStart(Context& /*context*/, Parse::NodeId /*parse_node*/)
-> bool {
return true;
}
auto HandleIfCondition(Context& context, Parse::NodeId parse_node) -> bool {
// Convert the condition to `bool`.
auto cond_value_id = context.node_stack().PopExpr();
cond_value_id = ConvertToBoolValue(context, 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);
// Start emitting the `then` block.
context.inst_block_stack().Pop();
context.inst_block_stack().Push(then_block_id);
context.AddCurrentCodeBlockToFunction();
context.node_stack().Push(parse_node, else_block_id);
return true;
}
auto HandleIfStatementElse(Context& context, Parse::NodeId parse_node) -> bool {
auto else_block_id = context.node_stack().Pop<Parse::NodeKind::IfCondition>();
// Switch to emitting the `else` block.
context.inst_block_stack().Push(else_block_id);
context.AddCurrentCodeBlockToFunction();
context.node_stack().Push(parse_node);
return true;
}
auto HandleIfStatement(Context& context, Parse::NodeId parse_node) -> bool {
switch (auto kind = context.node_stack().PeekParseNodeKind()) {
case Parse::NodeKind::IfCondition: {
// Branch from then block to else block, and start emitting the else
// block.
auto else_block_id =
context.node_stack().Pop<Parse::NodeKind::IfCondition>();
context.AddInst(SemIR::Branch{parse_node, else_block_id});
context.inst_block_stack().Pop();
context.inst_block_stack().Push(else_block_id);
break;
}
case Parse::NodeKind::IfStatementElse: {
// Branch from the then and else blocks to a new resumption block.
context.node_stack()
.PopAndDiscardSoloParseNode<Parse::NodeKind::IfStatementElse>();
context.AddConvergenceBlockAndPush(parse_node, /*num_blocks=*/2);
break;
}
default: {
CARBON_FATAL() << "Unexpected parse node at start of `if`: " << kind;
}
}
context.AddCurrentCodeBlockToFunction();
return true;
}
} // namespace Carbon::Check