public virtual void VisitForEachIn(BoundForEachIn node)
{
DefaultVisit(node);
}
public override void VisitForEachIn(BoundForEachIn node)
{
// Rules for for each in:
// * _branch becomes a fork and we create an empty fork;
// * Target for break/continue.
// Expression is executed on the default branch.
Visit(node.Expression);
MarkWrite(node.Target);
var block = new Block(_branch, FindLabel(node), true, true, null);
PushBlock(block);
_branch = block.Branch.Fork();
Visit(node.Body);
block.JoinBranch(_branch);
// Create an empty branch to signal that the body is optional.
block.JoinBranch(block.Branch.Fork());
PopBlock(block);
}
public override void VisitForEachIn(BoundForEachIn node)
{
_scope.MarkWrite(node.Target, BoundValueType.String);
base.VisitForEachIn(node);
}
public override void VisitForEachIn(BoundForEachIn node)
{
var temporary = node.Target as BoundTemporary;
if (temporary != null)
{
var statistic = GetStatistic(temporary);
if (statistic.WriteState != WriteType.Local)
statistic.WriteState = WriteType.DoNotRemove;
}
base.VisitForEachIn(node);
}
private void EmitForEachIn(BoundForEachIn node)
{
// Create break and continue labels and push them onto the stack.
var breakTarget = IL.DefineLabel(GetLabel(node));
_scope.BreakTargets.Push(breakTarget);
var continueTarget = IL.DefineLabel(GetLabel(node));
_scope.ContinueTargets.Push(continueTarget);
// Get the keys array.
var keys = IL.DeclareLocal(typeof(object[]));
_scope.EmitLoad(SpecialLocal.Runtime);
EmitBox(EmitExpression(node.Expression));
IL.EmitCall(_runtimeGetForEachKeys);
IL.Emit(OpCodes.Stloc, keys);
// Declare the index local.
var index = IL.DeclareLocal(typeof(int));
IL.EmitConstant(0);
IL.Emit(OpCodes.Stloc, index);
// Mark the start of the loop.
IL.MarkLabel(continueTarget);
// Test whether we're at the end of the loop.
// Load the current index.
IL.Emit(OpCodes.Ldloc, index);
// Load the length of the array.
IL.Emit(OpCodes.Ldloc, keys);
IL.Emit(OpCodes.Ldlen);
// (index >= keys.Length) -> breakTarget
IL.Emit(OpCodes.Bge, breakTarget.Label);
// Assign the current key to the target.
EmitSetVariable(
node.Target,
new BoundEmitExpression(
BoundValueType.Unknown,
() =>
{
// Load the element out of the index array.
IL.Emit(OpCodes.Ldloc, keys);
IL.Emit(OpCodes.Ldloc, index);
IL.Emit(OpCodes.Ldelem_Ref);
}
)
);
// Increment the index.
IL.Emit(OpCodes.Ldloc, index);
IL.EmitConstant(1);
IL.Emit(OpCodes.Add);
IL.Emit(OpCodes.Stloc, index);
// Emit the body.
EmitStatement(node.Body);
// Jump back to the beginning of the loop.
IL.Emit(OpCodes.Br, continueTarget.Label);
// Mark the end of the loop.
IL.MarkLabel(breakTarget);
// Pop the break and continue labels to make the previous ones available.
_scope.BreakTargets.Pop();
_scope.ContinueTargets.Pop();
}
