Files
carbon-lang/toolchain/check/handle_loop_statement.cpp
T
2023-12-05 22:45:57 +00:00

125 lines
4.2 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"
namespace Carbon::Check {
auto HandleBreakStatement(Context& /*context*/, Parse::NodeId /*parse_node*/)
-> bool {
return true;
}
auto HandleBreakStatementStart(Context& context, Parse::NodeId parse_node)
-> bool {
auto& stack = context.break_continue_stack();
if (stack.empty()) {
CARBON_DIAGNOSTIC(BreakOutsideLoop, Error,
"`break` can only be used in a loop.");
context.emitter().Emit(parse_node, BreakOutsideLoop);
} else {
context.AddInst(SemIR::Branch{parse_node, stack.back().break_target});
}
context.inst_block_stack().Pop();
context.inst_block_stack().PushUnreachable();
return true;
}
auto HandleContinueStatement(Context& /*context*/, Parse::NodeId /*parse_node*/)
-> bool {
return true;
}
auto HandleContinueStatementStart(Context& context, Parse::NodeId parse_node)
-> bool {
auto& stack = context.break_continue_stack();
if (stack.empty()) {
CARBON_DIAGNOSTIC(ContinueOutsideLoop, Error,
"`continue` can only be used in a loop.");
context.emitter().Emit(parse_node, ContinueOutsideLoop);
} else {
context.AddInst(SemIR::Branch{parse_node, stack.back().continue_target});
}
context.inst_block_stack().Pop();
context.inst_block_stack().PushUnreachable();
return true;
}
auto HandleForHeader(Context& context, Parse::NodeId parse_node) -> bool {
return context.TODO(parse_node, "HandleForHeader");
}
auto HandleForHeaderStart(Context& context, Parse::NodeId parse_node) -> bool {
return context.TODO(parse_node, "HandleForHeaderStart");
}
auto HandleForIn(Context& context, Parse::NodeId parse_node) -> bool {
context.decl_state_stack().Pop(DeclState::Var);
return context.TODO(parse_node, "HandleForIn");
}
auto HandleForStatement(Context& context, Parse::NodeId parse_node) -> bool {
return context.TODO(parse_node, "HandleForStatement");
}
auto HandleWhileConditionStart(Context& context, Parse::NodeId parse_node)
-> bool {
// Branch to the loop header block. Note that we create a new block here even
// if the current block is empty; this ensures that the loop always has a
// preheader block.
auto loop_header_id = context.AddDominatedBlockAndBranch(parse_node);
context.inst_block_stack().Pop();
// Start emitting the loop header block.
context.inst_block_stack().Push(loop_header_id);
context.AddCurrentCodeBlockToFunction();
context.node_stack().Push(parse_node, loop_header_id);
return true;
}
auto HandleWhileCondition(Context& context, Parse::NodeId parse_node) -> bool {
auto cond_value_id = context.node_stack().PopExpr();
auto loop_header_id =
context.node_stack().Peek<Parse::NodeKind::WhileConditionStart>();
cond_value_id = ConvertToBoolValue(context, parse_node, cond_value_id);
// Branch to either the loop body or the loop exit block.
auto loop_body_id =
context.AddDominatedBlockAndBranchIf(parse_node, cond_value_id);
auto loop_exit_id = context.AddDominatedBlockAndBranch(parse_node);
context.inst_block_stack().Pop();
// Start emitting the loop body.
context.inst_block_stack().Push(loop_body_id);
context.AddCurrentCodeBlockToFunction();
context.break_continue_stack().push_back(
{.break_target = loop_exit_id, .continue_target = loop_header_id});
context.node_stack().Push(parse_node, loop_exit_id);
return true;
}
auto HandleWhileStatement(Context& context, Parse::NodeId parse_node) -> bool {
auto loop_exit_id =
context.node_stack().Pop<Parse::NodeKind::WhileCondition>();
auto loop_header_id =
context.node_stack().Pop<Parse::NodeKind::WhileConditionStart>();
context.break_continue_stack().pop_back();
// Add the loop backedge.
context.AddInst(SemIR::Branch{parse_node, loop_header_id});
context.inst_block_stack().Pop();
// Start emitting the loop exit block.
context.inst_block_stack().Push(loop_exit_id);
context.AddCurrentCodeBlockToFunction();
return true;
}
} // namespace Carbon::Check