public override void Visit(While @while)
{
var expr = new ExpressionSimplifierVisitor().Visit(@while.Expr);
if (expr is Bool b && b.Value == false)
{
return;
}
_state.ConsolidateVariables();
_state.GoToNextLabel(out var startWhileLabel);
_llvmGenerator.Emit($"br label %{startWhileLabel}");
_state.DetachVarEnv();
_state.DetachVarEnv();
var reservedRegisters = _state.ReserveRegisterForCurrentVars(startWhileLabel);
_state.GoToNextLabel(out var whileLabel);
_llvmGenerator.Emit($"{whileLabel}:");
var startLength = _llvmGenerator.GetCurrentLength();
VisitBlock(@while.Block);
_state.ConsolidateVariables();
_state.RestorePreviousVarEnvWithMerge();
_llvmGenerator.Emit($"br label %{startWhileLabel}");
_state.CurrentLabel = startWhileLabel;
_llvmGenerator.Emit($"{startWhileLabel}:");
_state.RestorePreviousVarEnvWithMerge();
_state.RemoveReservedRegisters(reservedRegisters, out var removedRegisters);
_state.ConsolidateVariables(reservedRegisters);
var removedRegs = removedRegisters.ToHashSet();
var reservedToReplace = reservedRegisters.ToList().Where(reg => removedRegs.Contains(reg.Value.Register)).ToList();
_llvmGenerator.ReplaceRegisters(startLength, reservedToReplace.Select(res =>
(res.Value.Register, _state.VarToLabelToRegister[res.Key][_state.CurrentLabel].Register)).ToList());
var exprResult = new ExpressionGeneratorVisitor(_state).Visit(expr);
var endWhileLabel = _state.NewLabel;
_llvmGenerator.Emit($"br i1 {exprResult.Register}, label %{whileLabel}, label %{endWhileLabel}");
_state.CurrentLabel = endWhileLabel;
_llvmGenerator.Emit($"{endWhileLabel}:");
}
private void VisitBlockWithoutRestore(Block block)
{
_state.DetachVarEnv();
block.Stmts.ToList().ForEach(Visit);
}