public void EmitPrologue(EmitContext ec)
{
var fe_awaiter = new FieldExpr(awaiter, loc);
fe_awaiter.InstanceExpression = new CompilerGeneratedThis(ec.CurrentType, loc);
//
// awaiter = expr.GetAwaiter ();
//
fe_awaiter.EmitAssign(ec, expr, false, false);
is_completed.InstanceExpression = fe_awaiter;
is_completed.EmitBranchable(ec, resume_point, true);
var mg_completed = MethodGroupExpr.CreatePredefined(on_completed, fe_awaiter.Type, loc);
mg_completed.InstanceExpression = fe_awaiter;
var args = new Arguments(1);
var storey = (AsyncTaskStorey)machine_initializer.Storey;
var fe_cont = new FieldExpr(storey.Continuation, loc);
fe_cont.InstanceExpression = new CompilerGeneratedThis(ec.CurrentType, loc);
args.Add(new Argument(fe_cont));
//
// awaiter.OnCompleted (continuation);
//
mg_completed.EmitCall(ec, args);
base.DoEmit(ec);
}
public override void InjectYield(EmitContext ec, Expression expr, int resume_pc, bool unwind_protect, Label resume_point)
{
// Store the new value into current
var fe = new FieldExpr(((IteratorStorey)storey).CurrentField, loc);
fe.InstanceExpression = new CompilerGeneratedThis(storey.CurrentType, loc);
fe.EmitAssign(ec, expr, false, false);
base.InjectYield(ec, expr, resume_pc, unwind_protect, resume_point);
}
//
// Initializes all hoisted variables
//
public void EmitStoreyInstantiation (EmitContext ec, ExplicitBlock block)
{
// There can be only one instance variable for each storey type
if (Instance != null)
throw new InternalErrorException ();
//
// Create an instance of this storey
//
ResolveContext rc = new ResolveContext (ec.MemberContext);
rc.CurrentBlock = block;
var storey_type_expr = CreateStoreyTypeExpression (ec);
var source = new New (storey_type_expr, null, Location).Resolve (rc);
//
// When the current context is async (or iterator) lift local storey
// instantiation to the currect storey
//
if (ec.CurrentAnonymousMethod is StateMachineInitializer && (block.HasYield || block.HasAwait)) {
//
// Unfortunately, normal capture mechanism could not be used because we are
// too late in the pipeline and standart assign cannot be used either due to
// recursive nature of GetStoreyInstanceExpression
//
var field = ec.CurrentAnonymousMethod.Storey.AddCompilerGeneratedField (
LocalVariable.GetCompilerGeneratedName (block), storey_type_expr, true);
field.Define ();
field.Emit ();
var fexpr = new FieldExpr (field, Location);
fexpr.InstanceExpression = new CompilerGeneratedThis (ec.CurrentType, Location);
fexpr.EmitAssign (ec, source, false, false);
Instance = fexpr;
} else {
var local = TemporaryVariableReference.Create (source.Type, block, Location);
if (source.Type.IsStruct) {
local.LocalInfo.CreateBuilder (ec);
} else {
local.EmitAssign (ec, source);
}
Instance = local;
}
EmitHoistedFieldsInitialization (rc, ec);
// TODO: Implement properly
//SymbolWriter.DefineScopeVariable (ID, Instance.Builder);
}
public void EmitPrologue(EmitContext ec)
{
awaiter = ((AsyncTaskStorey)machine_initializer.Storey).AddAwaiter(expr.Type);
var fe_awaiter = new FieldExpr(awaiter, loc);
fe_awaiter.InstanceExpression = new CompilerGeneratedThis(ec.CurrentType, loc);
Label skip_continuation = ec.DefineLabel();
using (ec.With(BuilderContext.Options.OmitDebugInfo, true)) {
//
// awaiter = expr.GetAwaiter ();
//
fe_awaiter.EmitAssign(ec, expr, false, false);
Expression completed_expr;
if (IsDynamic)
{
var rc = new ResolveContext(ec.MemberContext);
Arguments dargs = new Arguments(1);
dargs.Add(new Argument(fe_awaiter));
completed_expr = new DynamicMemberBinder("IsCompleted", dargs, loc).Resolve(rc);
dargs = new Arguments(1);
dargs.Add(new Argument(completed_expr));
completed_expr = new DynamicConversion(ec.Module.Compiler.BuiltinTypes.Bool, 0, dargs, loc).Resolve(rc);
}
else
{
var pe = PropertyExpr.CreatePredefined(awaiter_definition.IsCompleted, loc);
pe.InstanceExpression = fe_awaiter;
completed_expr = pe;
}
completed_expr.EmitBranchable(ec, skip_continuation, true);
}
base.DoEmit(ec);
//
// The stack has to be empty before calling await continuation. We handle this
// by lifting values which would be left on stack into class fields. The process
// is quite complicated and quite hard to test because any expression can possibly
// leave a value on the stack.
//
// Following assert fails when some of expression called before is missing EmitToField
// or parent expression fails to find await in children expressions
//
ec.AssertEmptyStack();
var storey = (AsyncTaskStorey)machine_initializer.Storey;
if (IsDynamic)
{
storey.EmitAwaitOnCompletedDynamic(ec, fe_awaiter);
}
else
{
storey.EmitAwaitOnCompleted(ec, fe_awaiter);
}
// Return ok
machine_initializer.EmitLeave(ec, unwind_protect);
ec.MarkLabel(resume_point);
ec.MarkLabel(skip_continuation);
}
public void EmitPrologue(EmitContext ec)
{
var fe_awaiter = new FieldExpr(awaiter, loc);
fe_awaiter.InstanceExpression = new CompilerGeneratedThis(ec.CurrentType, loc);
//
// awaiter = expr.GetAwaiter ();
//
fe_awaiter.EmitAssign(ec, expr, false, false);
Label skip_continuation = ec.DefineLabel();
Expression completed_expr;
if (IsDynamic)
{
var rc = new ResolveContext(ec.MemberContext);
Arguments dargs = new Arguments(1);
dargs.Add(new Argument(fe_awaiter));
completed_expr = new DynamicMemberBinder("IsCompleted", dargs, loc).Resolve(rc);
}
else
{
var pe = PropertyExpr.CreatePredefined(is_completed, loc);
pe.InstanceExpression = fe_awaiter;
completed_expr = pe;
}
completed_expr.EmitBranchable(ec, skip_continuation, true);
base.DoEmit(ec);
//
// The stack has to be empty before calling await continuation. We handle this
// by lifting values which would be left on stack into class fields. The process
// is quite complicated and quite hard to test because any expression can possibly
// leave a value on the stack.
//
// Following assert fails when some of expression called before is missing EmitToField
// or parent expression fails to find await in children expressions
//
ec.AssertEmptyStack();
var args = new Arguments(1);
var storey = (AsyncTaskStorey)machine_initializer.Storey;
var fe_cont = new FieldExpr(storey.Continuation, loc);
fe_cont.InstanceExpression = new CompilerGeneratedThis(ec.CurrentType, loc);
args.Add(new Argument(fe_cont));
if (IsDynamic)
{
var rc = new ResolveContext(ec.MemberContext);
var mg_expr = new Invocation(new MemberAccess(fe_awaiter, "OnCompleted"), args).Resolve(rc);
ExpressionStatement es = (ExpressionStatement)mg_expr;
es.EmitStatement(ec);
}
else
{
var mg_completed = MethodGroupExpr.CreatePredefined(on_completed, fe_awaiter.Type, loc);
mg_completed.InstanceExpression = fe_awaiter;
//
// awaiter.OnCompleted (continuation);
//
mg_completed.EmitCall(ec, args);
}
// Return ok
machine_initializer.EmitLeave(ec, unwind_protect);
ec.MarkLabel(resume_point);
ec.MarkLabel(skip_continuation);
}
public void EmitPrologue(EmitContext ec)
{
var fe_awaiter = new FieldExpr(awaiter, loc);
fe_awaiter.InstanceExpression = new CompilerGeneratedThis(ec.CurrentType, loc);
//
// awaiter = expr.GetAwaiter ();
//
fe_awaiter.EmitAssign(ec, expr, false, false);
Label skip_continuation = ec.DefineLabel();
is_completed.InstanceExpression = fe_awaiter;
is_completed.EmitBranchable(ec, skip_continuation, true);
base.DoEmit(ec);
FieldSpec[] stack_fields = null;
TypeSpec[] stack = null;
//
// Here is the clever bit. We know that await statement has to yield the control
// back but it can appear inside almost any expression. This means the stack can
// contain any depth of values and same values have to be present when the continuation
// handles control back.
//
// For example: await a + await b
//
// In this case we fabricate a static stack forwarding method which moves the values
// from the stack to async storey fields. On re-entry point we restore exactly same
// stack using these fields.
//
// We fabricate a static method because we don't want to touch original stack and
// the instance method would require `this' as the first stack value on the stack
//
if (ec.StackHeight > 0)
{
var async_storey = (AsyncTaskStorey)machine_initializer.Storey;
stack = ec.GetStackTypes();
var method = async_storey.GetStackForwarder(stack, out stack_fields);
ec.EmitThis();
ec.Emit(OpCodes.Call, method);
}
var mg_completed = MethodGroupExpr.CreatePredefined(on_completed, fe_awaiter.Type, loc);
mg_completed.InstanceExpression = fe_awaiter;
var args = new Arguments(1);
var storey = (AsyncTaskStorey)machine_initializer.Storey;
var fe_cont = new FieldExpr(storey.Continuation, loc);
fe_cont.InstanceExpression = new CompilerGeneratedThis(ec.CurrentType, loc);
args.Add(new Argument(fe_cont));
//
// awaiter.OnCompleted (continuation);
//
mg_completed.EmitCall(ec, args);
// Return ok
machine_initializer.EmitLeave(ec, unwind_protect);
ec.MarkLabel(resume_point);
if (stack_fields != null)
{
for (int i = 0; i < stack_fields.Length; ++i)
{
ec.EmitThis();
var field = stack_fields[i];
//
// We don't store `this' because it can be easily re-created
//
if (field == null)
{
continue;
}
if (stack[i] is ReferenceContainer)
{
ec.Emit(OpCodes.Ldflda, field);
}
else
{
ec.Emit(OpCodes.Ldfld, field);
}
}
}
ec.MarkLabel(skip_continuation);
}
