public override void VisitFor(BoundFor node)
{
// Rules for for:
// * _branch stays default when IsTrue(Test); otherwise _branch
// becomes a fork;
// * Target for break/continue;
// * Increment is only executed when the default branch reaches
// the end or a continue was executed.
// Initialization and test are executed on the current branch.
Visit(node.Initialization);
Visit(node.Test);
var block = new Block(_branch, FindLabel(node), true, true, null);
_branch = block.Branch.Fork();
PushBlock(block);
Visit(node.Body);
bool wasKilled = _branch.IsKilled;
// Only visit the increment when then default branch flows there
// or a continue was executed.
if (!_branch.IsKilled || block.ContinueTaken)
{
// We need to restore the branch because if the branch is
// killed, but we have a continue, the test is still done on
// the branch.
_branch.IsKilled = false;
Visit(node.Increment);
}
if (!wasKilled)
block.JoinBranch(_branch);
// Create an extra empty branch when the test wasn't unconditional.
if (node.Test != null && ToBoolean(node.Test) != true)
block.JoinBranch(block.Branch.Fork());
PopBlock(block);
}
public virtual void VisitFor(BoundFor node)
{
DefaultVisit(node);
}
private void EmitFor(BoundFor node)
{
// Push the break and continue targets onto the stack.
var breakTarget = IL.DefineLabel(GetLabel(node));
_scope.BreakTargets.Push(breakTarget);
var continueTarget = IL.DefineLabel(GetLabel(node));
_scope.ContinueTargets.Push(continueTarget);
// At the start of our block, we perform any initialization.
if (node.Initialization != null)
EmitStatement(node.Initialization);
// If we have a test, we perform the test at the start of every
// iteration.
var startTarget = IL.DefineLabel();
IL.MarkLabel(startTarget);
if (node.Test != null)
EmitTest(node.Test, breakTarget.Label, true);
// Add the body.
EmitStatement(node.Body);
// Increment is done at the end.
IL.MarkLabel(continueTarget);
if (node.Increment != null)
EmitStatement(node.Increment);
// Jump back to the start of the loop.
IL.Emit(OpCodes.Br, startTarget);
// Mark the end of the loop.
IL.MarkLabel(breakTarget);
// Remove the break and continue targets to make the previous ones
// visible.
_scope.BreakTargets.Pop();
_scope.ContinueTargets.Pop();
}