protected override BoundStatement RewriteIfStatement(BoundIfStatement statement)
{
/* if(<condition>) <true> else <false>
*
* condiditonal branch !<condition> false
* <true>
* branch end
*
* #false
* <false>
* #end
*/
var falseLabel = CreateNextLabel();
var endLabel = CreateNextLabel();
var endBranch = new BoundBranchStatement(endLabel);
var statements = ImmutableArray.CreateBuilder <BoundStatement>();
if (statement.FalseBranch != null)
{
var condBranch = new BoundConditionalBranchStatement(falseLabel, statement.Condition, false);
statements.AddRange(condBranch, statement.TrueBranch, endBranch, new BoundLabel(falseLabel), statement.FalseBranch);
}
else
{
var condBranch = new BoundConditionalBranchStatement(endLabel, statement.Condition, false);
statements.AddRange(condBranch, statement.TrueBranch);
}
statements.Add(new BoundLabel(endLabel));
return(RewriteStatement(new BoundBlock(statements.ToImmutable())));
}
protected override BoundStatement RewriteWhileStatement(BoundWhileStatement statement)
{
/* while(<condition>) <body>
*
* branch conditionCheck
* #start
* <body>
* #conditionCheck
* conditional branch <condition> start
*/
var startLabel = CreateNextLabel();
var conditionCheckLabel = CreateNextLabel();
var firstBranch = new BoundBranchStatement(conditionCheckLabel);
var condBranch = new BoundConditionalBranchStatement(startLabel, statement.Condition, true);
var statements = ImmutableArray.CreateBuilder <BoundStatement>();
statements.AddRange(new BoundStatement[] {
firstBranch,
new BoundLabel(startLabel),
statement.Body
});
if (statement.AddContinue)
{
statements.Add(new BoundLabel(statement.ContinueLabel));
}
statements.AddRange(new BoundStatement[] {
new BoundLabel(conditionCheckLabel),
condBranch,
new BoundLabel(statement.BreakLabel)
});
var rewrite = RewriteStatement(new BoundBlock(statements.ToImmutable()));
return(rewrite);
}
protected virtual BoundStatement RewriteBranchStatement(BoundBranchStatement statement)
{
return(statement);
}
private void OutputBranch(BoundBranchStatement node, string prefix)
{
builder.AddFragment(new OutputFragment(prefix, DefaultColour));
builder.AddFragment(new OutputFragment("goto ", BranchColour));
builder.AddFragment(new OutputFragment(node.Label.Name, LabelColour));
}
