// Traverses the tree and generates output code
public void Generate(CilEmitter emitter)
{
emitter.BeginProgram();
ILabel begin = emitter.GenerateLabel();
ILabel end = emitter.GenerateLabel();
begin.Emit();
root.Generate(emitter, begin, end);
end.Emit();
emitter.WriteExecutable();
}
protected override void DoGenerate(CilEmitter emitter)
{
ILabel ifLabel = emitter.GenerateLabel();
ILabel elseLabel = emitter.GenerateLabel();
logicalExpression.EmitRValue(emitter);
elseLabel.EmitJumpIfFalse();
ifLabel.Emit();
ifStatement.Generate(emitter, ifLabel, after);
after.EmitJump();
elseLabel.Emit();
elseStatement.Generate(emitter, elseLabel, after);
}
protected override void DoGenerate(CilEmitter emitter)
{
ILabel whileLabel = emitter.GenerateLabel();
logicalExpr.EmitRValue(emitter);
after.EmitJumpIfFalse();
whileLabel.Emit();
statement.Generate(emitter, whileLabel, begin);
begin.EmitJump();
/*
*
* logicalExpression.jumping(0, after)
*
* create label
*
* emit label
*
* stmt.Gen(label, begin)
*
* emit goto begin
*
*/
}
protected override void DoGenerate(CilEmitter emitter)
{
ILabel comparisonLabel = emitter.GenerateLabel();
ILabel contentsLabel = emitter.GenerateLabel();
variable = emitter.EmitLocalVarDeclaration("STEPS_LOOP_VAR" + stepCountExpr.lexline + "_" + stepCountExpr.lexline, typeof(int));
stepCountExpr.EmitRValue(emitter);
variable.EmitAssignment();
comparisonLabel.Emit();
variable.EmitValue();
emitter.EmitInt32(0);
emitter.EmitComparison(">");
after.EmitJumpIfFalse();
contentsLabel.Emit();
statement.Generate(emitter, contentsLabel, comparisonLabel);
variable.EmitValue();
emitter.EmitInt32(1);
emitter.EmitBinaryOperator("-");
variable.EmitAssignment();
comparisonLabel.EmitJump();
/*
*
* logicalExpression.jumping(0, after)
*
* create label
*
* emit label
*
* stmt.Gen(label, begin)
*
* emit goto begin
*
*/
}
protected override void DoGenerate(CilEmitter emitter)
{
ILabel doEnd = emitter.GenerateLabel();
statement.Generate(emitter, begin, doEnd);
doEnd.Emit();
logicalExpr.EmitRValue(emitter);
begin.EmitJumpIfTrue();
}
protected override void DoGenerate(CilEmitter emitter)
{
ILabel contentsLabel = emitter.GenerateLabel();
emitter.EmitBool(true);
after.EmitJumpIfFalse();
contentsLabel.Emit();
contents.Generate(emitter, contentsLabel, begin);
begin.EmitJump();
}
protected override void DoGenerate(CilEmitter emitter)
{
if (first == Statement.Null)
{
second.Generate(emitter, begin, after);
}
else if (second == Statement.Null)
{
first.Generate(emitter, begin, after);
}
else
{
// Create new label between the two statements
ILabel midpoint = emitter.GenerateLabel();
first.Generate(emitter, begin, midpoint);
midpoint.Emit();
second.Generate(emitter, midpoint, after);
}
}
protected override void DoGenerate(CilEmitter emitter)
{
ILabel contentsLabel = emitter.GenerateLabel();
logicalExpr.EmitRValue(emitter); // Generate rvalue from logical expression.
after.EmitJumpIfFalse(); // Skip the if body if false
contentsLabel.Emit();
contents.Generate(emitter, contentsLabel, after);
/*
* generate new label
*
* call logicalExpr.Jumping(0, after) to have it generate the jumping code.
*
* emitLabel(new label);
*
* stmt.Gen(label, after);
*
*/
}
