public override void Emit(EmitContext ec)
{
//
// Load Iterator storey instance
//
method.Storey.Instance.Emit(ec);
//
// Initialize iterator PC when it's unitialized
//
if (IsEnumerable)
{
ILGenerator ig = ec.ig;
ig.Emit(OpCodes.Dup);
IntConstant.EmitInt(ig, (int)State.Uninitialized);
FieldInfo field = IteratorHost.PC.FieldBuilder;
#if GMCS_SOURCE
if (Storey.MemberName.IsGeneric)
{
field = TypeBuilder.GetField(Storey.Instance.Type, field);
}
#endif
ig.Emit(OpCodes.Stfld, field);
}
}
//
// Called back from Yield
//
public void MarkYield(EmitContext ec, Expression expr, int resume_pc, bool unwind_protect, Label resume_point)
{
ILGenerator ig = ec.ig;
// Store the new current
ig.Emit(OpCodes.Ldarg_0);
expr.Emit(ec);
ig.Emit(OpCodes.Stfld, IteratorHost.CurrentField.FieldBuilder);
// store resume program-counter
ig.Emit(OpCodes.Ldarg_0);
IntConstant.EmitInt(ig, resume_pc);
ig.Emit(OpCodes.Stfld, IteratorHost.PC.FieldBuilder);
// mark finally blocks as disabled
if (unwind_protect && skip_finally != null)
{
ig.Emit(OpCodes.Ldc_I4_1);
ig.Emit(OpCodes.Stloc, skip_finally);
}
// Return ok
ig.Emit(unwind_protect ? OpCodes.Leave : OpCodes.Br, move_next_ok);
ig.MarkLabel(resume_point);
}
public void EmitDispose(EmitContext ec)
{
ILGenerator ig = ec.ig;
Label end = ig.DefineLabel();
Label [] labels = null;
int n_resume_points = resume_points == null ? 0 : resume_points.Count;
for (int i = 0; i < n_resume_points; ++i)
{
ResumableStatement s = (ResumableStatement)resume_points [i];
Label ret = s.PrepareForDispose(ec, end);
if (ret.Equals(end) && labels == null)
{
continue;
}
if (labels == null)
{
labels = new Label [resume_points.Count + 1];
for (int j = 0; j <= i; ++j)
{
labels [j] = end;
}
}
labels [i + 1] = ret;
}
if (labels != null)
{
current_pc = ec.GetTemporaryLocal(TypeManager.uint32_type);
ig.Emit(OpCodes.Ldarg_0);
ig.Emit(OpCodes.Ldfld, IteratorHost.PC.FieldBuilder);
ig.Emit(OpCodes.Stloc, current_pc);
}
ig.Emit(OpCodes.Ldarg_0);
IntConstant.EmitInt(ig, (int)State.After);
ig.Emit(OpCodes.Stfld, IteratorHost.PC.FieldBuilder);
if (labels != null)
{
//SymbolWriter.StartIteratorDispatcher (ec.ig);
ig.Emit(OpCodes.Ldloc, current_pc);
ig.Emit(OpCodes.Switch, labels);
//SymbolWriter.EndIteratorDispatcher (ec.ig);
foreach (ResumableStatement s in resume_points)
{
s.EmitForDispose(ec, this, end, true);
}
}
ig.MarkLabel(end);
}
void EmitMoveNext_NoResumePoints(EmitContext ec, Block original_block)
{
ILGenerator ig = ec.ig;
ig.Emit(OpCodes.Ldarg_0);
ig.Emit(OpCodes.Ldfld, IteratorHost.PC.FieldBuilder);
ig.Emit(OpCodes.Ldarg_0);
IntConstant.EmitInt(ig, (int)State.After);
ig.Emit(OpCodes.Stfld, IteratorHost.PC.FieldBuilder);
// We only care if the PC is zero (start executing) or non-zero (don't do anything)
ig.Emit(OpCodes.Brtrue, move_next_error);
SymbolWriter.StartIteratorBody(ec.ig);
original_block.Emit(ec);
SymbolWriter.EndIteratorBody(ec.ig);
ig.MarkLabel(move_next_error);
ig.Emit(OpCodes.Ldc_I4_0);
ig.Emit(OpCodes.Ret);
}
protected override void DoEmit(EmitContext ec)
{
ILGenerator ig = ec.ig;
Label label_init = ig.DefineLabel();
ig.Emit(OpCodes.Ldarg_0);
ig.Emit(OpCodes.Ldflda, host.PC.FieldBuilder);
IntConstant.EmitInt(ig, (int)Iterator.State.Start);
IntConstant.EmitInt(ig, (int)Iterator.State.Uninitialized);
ig.Emit(OpCodes.Call, TypeManager.int_interlocked_compare_exchange);
IntConstant.EmitInt(ig, (int)Iterator.State.Uninitialized);
ig.Emit(OpCodes.Bne_Un_S, label_init);
ig.Emit(OpCodes.Ldarg_0);
ig.Emit(OpCodes.Ret);
ig.MarkLabel(label_init);
new_storey.Emit(ec);
ig.Emit(OpCodes.Ret);
}
internal void EmitMoveNext(EmitContext ec, Block original_block)
{
ILGenerator ig = ec.ig;
move_next_ok = ig.DefineLabel();
move_next_error = ig.DefineLabel();
if (resume_points == null)
{
EmitMoveNext_NoResumePoints(ec, original_block);
return;
}
current_pc = ec.GetTemporaryLocal(TypeManager.uint32_type);
ig.Emit(OpCodes.Ldarg_0);
ig.Emit(OpCodes.Ldfld, IteratorHost.PC.FieldBuilder);
ig.Emit(OpCodes.Stloc, current_pc);
// We're actually in state 'running', but this is as good a PC value as any if there's an abnormal exit
ig.Emit(OpCodes.Ldarg_0);
IntConstant.EmitInt(ig, (int)State.After);
ig.Emit(OpCodes.Stfld, IteratorHost.PC.FieldBuilder);
Label [] labels = new Label [1 + resume_points.Count];
labels [0] = ig.DefineLabel();
bool need_skip_finally = false;
for (int i = 0; i < resume_points.Count; ++i)
{
ResumableStatement s = (ResumableStatement)resume_points [i];
need_skip_finally |= s is ExceptionStatement;
labels [i + 1] = s.PrepareForEmit(ec);
}
if (need_skip_finally)
{
skip_finally = ec.GetTemporaryLocal(TypeManager.bool_type);
ig.Emit(OpCodes.Ldc_I4_0);
ig.Emit(OpCodes.Stloc, skip_finally);
}
SymbolWriter.StartIteratorDispatcher(ec.ig);
ig.Emit(OpCodes.Ldloc, current_pc);
ig.Emit(OpCodes.Switch, labels);
ig.Emit(OpCodes.Br, move_next_error);
SymbolWriter.EndIteratorDispatcher(ec.ig);
ig.MarkLabel(labels [0]);
SymbolWriter.StartIteratorBody(ec.ig);
original_block.Emit(ec);
SymbolWriter.EndIteratorBody(ec.ig);
SymbolWriter.StartIteratorDispatcher(ec.ig);
ig.Emit(OpCodes.Ldarg_0);
IntConstant.EmitInt(ig, (int)State.After);
ig.Emit(OpCodes.Stfld, IteratorHost.PC.FieldBuilder);
ig.MarkLabel(move_next_error);
ig.Emit(OpCodes.Ldc_I4_0);
ig.Emit(OpCodes.Ret);
ig.MarkLabel(move_next_ok);
ig.Emit(OpCodes.Ldc_I4_1);
ig.Emit(OpCodes.Ret);
SymbolWriter.EndIteratorDispatcher(ec.ig);
}