//
// iterators.cs: Support for implementing iterators
//
// Author:
// Miguel de Icaza (miguel@ximian.com)
// Marek Safar (marek.safar@gmail.com)
//
// Dual licensed under the terms of the MIT X11 or GNU GPL
// Copyright 2003 Ximian, Inc.
// Copyright 2003-2008 Novell, Inc.
//
// TODO:
// Flow analysis for Yield.
//
using System;
using System.Collections;
using System.Reflection;
using System.Reflection.Emit;
using System.Collections.Generic;
namespace Mono.CSharp {
public class Yield : ResumableStatement {
Expression expr;
bool unwind_protect;
Iterator iterator;
int resume_pc;
public override IEnumerable<IVisitable> GetChildrenX(object context)
{
return Visitable.Container().Single("iterator", iterator);
}
public override string GetNameX()
{
return null;
}
public Yield (Expression expr, Location l)
{
this.expr = expr;
loc = l;
}
public static bool CheckContext (ResolveContext ec, Location loc)
{
//
// We can't use `ec.InUnsafe' here because it's allowed to have an iterator
// inside an unsafe class. See test-martin-29.cs for an example.
//
if (!ec.CurrentAnonymousMethod.IsIterator) {
ec.Report.Error (1621, loc,
"The yield statement cannot be used inside " +
"anonymous method blocks");
return false;
}
return true;
}
public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
{
expr.MutateHoistedGenericType (storey);
}
public override bool Resolve (BlockContext ec)
{
expr = expr.Resolve (ec);
if (expr == null)
return false;
Report.Debug (64, "RESOLVE YIELD #1", this, ec, expr, expr.GetType (),
ec.CurrentAnonymousMethod, ec.CurrentIterator);
if (!CheckContext (ec, loc))
return false;
iterator = ec.CurrentIterator;
if (expr.Type != iterator.OriginalIteratorType) {
expr = Convert.ImplicitConversionRequired (
ec, expr, iterator.OriginalIteratorType, loc);
if (expr == null)
return false;
}
if (!ec.CurrentBranching.CurrentUsageVector.IsUnreachable)
unwind_protect = ec.CurrentBranching.AddResumePoint (this, loc, out resume_pc);
return true;
}
protected override void DoEmit (EmitContext ec)
{
iterator.MarkYield (ec, expr, resume_pc, unwind_protect, resume_point);
}
protected override void CloneTo (CloneContext clonectx, Statement t)
{
Yield target = (Yield) t;
target.expr = expr.Clone (clonectx);
}
}
public class YieldBreak : ExitStatement
{
Iterator iterator;
public override IEnumerable<IVisitable> GetChildrenX(object context)
{
return Visitable.Container().Single("iterator", iterator);
}
public override string GetNameX()
{
return null;
}
public YieldBreak (Location l)
{
loc = l;
}
public override void Error_FinallyClause (Report Report)
{
Report.Error (1625, loc, "Cannot yield in the body of a finally clause");
}
protected override void CloneTo (CloneContext clonectx, Statement target)
{
throw new NotSupportedException ();
}
protected override bool DoResolve (BlockContext ec)
{
iterator = ec.CurrentIterator;
return Yield.CheckContext (ec, loc);
}
protected override void DoEmit (EmitContext ec)
{
iterator.EmitYieldBreak (ec.ig, unwind_protect);
}
public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
{
// nothing to do
}
}
//
// Wraps method block into iterator wrapper block
//
class IteratorStatement : Statement
{
Iterator iterator;
Block original_block;
public override IEnumerable<IVisitable> GetChildrenX(object context)
{
return Visitable.Container()
.Single("iterator", iterator)
.Single("original_block", original_block);
}
public override string GetNameX()
{
return null;
}
public IteratorStatement (Iterator iterator, Block original_block)
{
this.iterator = iterator;
this.original_block = original_block;
this.loc = iterator.Location;
}
protected override void CloneTo (CloneContext clonectx, Statement target)
{
IteratorStatement t = (IteratorStatement) target;
t.original_block = (ExplicitBlock) original_block.Clone (clonectx);
t.iterator = (Iterator) iterator.Clone (clonectx);
}
public override bool Resolve (BlockContext ec)
{
ec.StartFlowBranching (iterator);
bool ok = original_block.Resolve (ec);
ec.EndFlowBranching ();
return ok;
}
protected override void DoEmit (EmitContext ec)
{
iterator.EmitMoveNext (ec, original_block);
}
public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
{
original_block.MutateHoistedGenericType (storey);
iterator.MutateHoistedGenericType (storey);
}
}
public class IteratorStorey : AnonymousMethodStorey
{
class IteratorMethod : Method
{
readonly IteratorStorey host;
public IteratorMethod (IteratorStorey host, FullNamedExpression returnType, int mod, MemberName name)
: base (host, null, returnType, mod | Modifiers.DEBUGGER_HIDDEN | Modifiers.COMPILER_GENERATED,
name, ParametersCompiled.EmptyReadOnlyParameters, null)
{
this.host = host;
Block = new ToplevelBlock (Compiler, host.Iterator.Container.Toplevel, ParametersCompiled.EmptyReadOnlyParameters, Location);
}
public override EmitContext CreateEmitContext (ILGenerator ig)
{
EmitContext ec = new EmitContext (
this, ig, MemberType);
ec.CurrentAnonymousMethod = host.Iterator;
return ec;
}
}
class GetEnumeratorMethod : IteratorMethod
{
sealed class GetEnumeratorStatement : Statement
{
IteratorStorey host;
IteratorMethod host_method;
Expression new_storey;
public override IEnumerable<IVisitable> GetChildrenX(object context)
{
return Visitable.Container()
.Single("host", host)
.Single("host_method", host_method);
}
public override string GetNameX()
{
return null;
}
public GetEnumeratorStatement (IteratorStorey host, IteratorMethod host_method)
{
this.host = host;
this.host_method = host_method;
loc = host_method.Location;
}
protected override void CloneTo (CloneContext clonectx, Statement target)
{
throw new NotSupportedException ();
}
public override bool Resolve (BlockContext ec)
{
TypeExpression storey_type_expr = new TypeExpression (host.TypeBuilder, loc);
ArrayList init = null;
if (host.hoisted_this != null) {
init = new ArrayList (host.hoisted_params == null ? 1 : host.HoistedParameters.Count + 1);
HoistedThis ht = host.hoisted_this;
FieldExpr from = new FieldExpr (ht.Field.FieldBuilder, loc);
from.InstanceExpression = CompilerGeneratedThis.Instance;
init.Add (new ElementInitializer (ht.Field.Name, from, loc));
}
if (host.hoisted_params != null) {
if (init == null)
init = new ArrayList (host.HoistedParameters.Count);
for (int i = 0; i < host.hoisted_params.Count; ++i) {
HoistedParameter hp = (HoistedParameter) host.hoisted_params [i];
HoistedParameter hp_cp = (HoistedParameter) host.hoisted_params_copy [i];
FieldExpr from = new FieldExpr (hp_cp.Field.FieldBuilder, loc);
from.InstanceExpression = CompilerGeneratedThis.Instance;
init.Add (new ElementInitializer (hp.Field.Name, from, loc));
}
}
if (init != null) {
new_storey = new NewInitialize (storey_type_expr, null,
new CollectionOrObjectInitializers (init, loc), loc);
} else {
new_storey = new New (storey_type_expr, null, loc);
}
new_storey = new_storey.Resolve (ec);
if (new_storey != null)
new_storey = Convert.ImplicitConversionRequired (ec, new_storey, host_method.MemberType, loc);
if (TypeManager.int_interlocked_compare_exchange == null) {
Type t = TypeManager.CoreLookupType (ec.Compiler, "System.Threading", "Interlocked", Kind.Class, true);
if (t != null) {
TypeManager.int_interlocked_compare_exchange = TypeManager.GetPredefinedMethod (
t, "CompareExchange", loc, TypeManager.int32_type,
TypeManager.int32_type, TypeManager.int32_type);
}
}
ec.CurrentBranching.CurrentUsageVector.Goto ();
return true;
}
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);
}
public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
{
throw new NotSupportedException ();
}
}
public GetEnumeratorMethod (IteratorStorey host, FullNamedExpression returnType, MemberName name)
: base (host, returnType, 0, name)
{
Block.AddStatement (new GetEnumeratorStatement (host, this));
}
}
class DisposeMethod : IteratorMethod
{
sealed class DisposeMethodStatement : Statement
{
Iterator iterator;
public override IEnumerable<IVisitable> GetChildrenX(object context)
{
return Visitable.Container().Single("iterator", iterator);
}
public override string GetNameX()
{
return null;
}
public DisposeMethodStatement (Iterator iterator)
{
this.iterator = iterator;
this.loc = iterator.Location;
}
protected override void CloneTo (CloneContext clonectx, Statement target)
{
throw new NotSupportedException ();
}
public override bool Resolve (BlockContext ec)
{
return true;
}
protected override void DoEmit (EmitContext ec)
{
iterator.EmitDispose (ec);
}
public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
{
throw new NotSupportedException ();
}
}
public DisposeMethod (IteratorStorey host)
: base (host, TypeManager.system_void_expr, Modifiers.PUBLIC, new MemberName ("Dispose", host.Location))
{
host.AddMethod (this);
Block = new ToplevelBlock (Compiler, host.Iterator.Container, ParametersCompiled.EmptyReadOnlyParameters, Location);
Block.AddStatement (new DisposeMethodStatement (host.Iterator));
}
}
//
// Uses Method as method info
//
class DynamicMethodGroupExpr : MethodGroupExpr
{
readonly Method method;
public DynamicMethodGroupExpr (Method method, Location loc)
: base (null, loc)
{
this.method = method;
}
public override Expression DoResolve (ResolveContext ec)
{
Methods = new MethodBase [] { method.MethodBuilder };
type = method.Parent.TypeBuilder;
InstanceExpression = new CompilerGeneratedThis (type, Location);
return base.DoResolve (ec);
}
}
class DynamicFieldExpr : FieldExpr
{
readonly Field field;
public DynamicFieldExpr (Field field, Location loc)
: base (loc)
{
this.field = field;
}
public override Expression DoResolve (ResolveContext ec)
{
FieldInfo = field.FieldBuilder;
type = TypeManager.TypeToCoreType (FieldInfo.FieldType);
InstanceExpression = new CompilerGeneratedThis (type, Location);
return base.DoResolve (ec);
}
}
public readonly Iterator Iterator;
TypeExpr iterator_type_expr;
Field pc_field;
Field current_field;
TypeExpr enumerator_type;
TypeExpr enumerable_type;
TypeArguments generic_args;
TypeExpr generic_enumerator_type;
TypeExpr generic_enumerable_type;
ArrayList hoisted_params_copy;
int local_name_idx;
public IteratorStorey (Iterator iterator)
: base (iterator.Container.Toplevel, iterator.Host,
iterator.OriginalMethod as MemberBase, iterator.GenericMethod, "Iterator")
{
this.Iterator = iterator;
}
public Field PC {
get { return pc_field; }
}
public Field CurrentField {
get { return current_field; }
}
public ArrayList HoistedParameters {
get { return hoisted_params; }
}
protected override TypeExpr [] ResolveBaseTypes (out TypeExpr base_class)
{
iterator_type_expr = new TypeExpression (MutateType (Iterator.OriginalIteratorType), Location);
generic_args = new TypeArguments (iterator_type_expr);
ArrayList list = new ArrayList ();
if (Iterator.IsEnumerable) {
enumerable_type = new TypeExpression (
TypeManager.ienumerable_type, Location);
list.Add (enumerable_type);
if (TypeManager.generic_ienumerable_type != null) {
generic_enumerable_type = new GenericTypeExpr (
TypeManager.generic_ienumerable_type,
generic_args, Location);
list.Add (generic_enumerable_type);
}
}
enumerator_type = new TypeExpression (
TypeManager.ienumerator_type, Location);
list.Add (enumerator_type);
list.Add (new TypeExpression (TypeManager.idisposable_type, Location));
if (TypeManager.generic_ienumerator_type != null) {
generic_enumerator_type = new GenericTypeExpr (
TypeManager.generic_ienumerator_type,
generic_args, Location);
list.Add (generic_enumerator_type);
}
type_bases = list;
return base.ResolveBaseTypes (out base_class);
}
protected override string GetVariableMangledName (LocalInfo local_info)
{
return "<" + local_info.Name + ">__" + local_name_idx++.ToString ();
}
public void DefineIteratorMembers ()
{
pc_field = AddCompilerGeneratedField ("$PC", TypeManager.system_int32_expr);
current_field = AddCompilerGeneratedField ("$current", iterator_type_expr);
if (hoisted_params != null) {
//
// Iterators are independent, each GetEnumerator call has to
// create same enumerator therefore we have to keep original values
// around for re-initialization
//
// TODO: Do it for assigned/modified parameters only
//
hoisted_params_copy = new ArrayList (hoisted_params.Count);
foreach (HoistedParameter hp in hoisted_params) {
hoisted_params_copy.Add (new HoistedParameter (hp, "<$>" + hp.Field.Name));
}
}
if (generic_enumerator_type != null)
Define_Current (true);
Define_Current (false);
new DisposeMethod (this);
Define_Reset ();
if (Iterator.IsEnumerable) {
MemberName name = new MemberName (QualifiedAliasMember.GlobalAlias, "System", null, Location);
name = new MemberName (name, "Collections", Location);
name = new MemberName (name, "IEnumerable", Location);
name = new MemberName (name, "GetEnumerator", Location);
if (generic_enumerator_type != null) {
Method get_enumerator = new IteratorMethod (this, enumerator_type, 0, name);
name = new MemberName (name.Left.Left, "Generic", Location);
name = new MemberName (name, "IEnumerable", generic_args, Location);
name = new MemberName (name, "GetEnumerator", Location);
Method gget_enumerator = new GetEnumeratorMethod (this, generic_enumerator_type, name);
//
// Just call generic GetEnumerator implementation
//
get_enumerator.Block.AddStatement (
new Return (new Invocation (new DynamicMethodGroupExpr (gget_enumerator, Location), null), Location));
AddMethod (get_enumerator);
AddMethod (gget_enumerator);
} else {
AddMethod (new GetEnumeratorMethod (this, enumerator_type, name));
}
}
}
protected override void EmitHoistedParameters (EmitContext ec, ArrayList hoisted)
{
base.EmitHoistedParameters (ec, hoisted);
base.EmitHoistedParameters (ec, hoisted_params_copy);
}
void Define_Current (bool is_generic)
{
TypeExpr type;
MemberName name = new MemberName (QualifiedAliasMember.GlobalAlias, "System", null, Location);
name = new MemberName (name, "Collections", Location);
if (is_generic) {
name = new MemberName (name, "Generic", Location);
name = new MemberName (name, "IEnumerator", generic_args, Location);
type = iterator_type_expr;
} else {
name = new MemberName (name, "IEnumerator");
type = TypeManager.system_object_expr;
}
name = new MemberName (name, "Current", Location);
ToplevelBlock get_block = new ToplevelBlock (Compiler, Location);
get_block.AddStatement (new Return (new DynamicFieldExpr (CurrentField, Location), Location));
Accessor getter = new Accessor (get_block, 0, null, null, Location);
Property current = new Property (
this, type, Modifiers.DEBUGGER_HIDDEN, name, null, getter, null, false);
AddProperty (current);
}
void Define_Reset ()
{
Method reset = new Method (
this, null, TypeManager.system_void_expr,
Modifiers.PUBLIC | Modifiers.DEBUGGER_HIDDEN,
new MemberName ("Reset", Location),
ParametersCompiled.EmptyReadOnlyParameters, null);
AddMethod (reset);
reset.Block = new ToplevelBlock (Compiler, Location);
Type ex_type = TypeManager.CoreLookupType (Compiler, "System", "NotSupportedException", Kind.Class, true);
if (ex_type == null)
return;
reset.Block.AddStatement (new Throw (new New (new TypeExpression (ex_type, Location), null, Location), Location));
}
}
//
// Iterators are implemented as hidden anonymous block
//
public class Iterator : AnonymousExpression {
public readonly IMethodData OriginalMethod;
AnonymousMethodMethod method;
public readonly TypeContainer Host;
public readonly bool IsEnumerable;
public override IEnumerable<IVisitable> GetChildrenX(object context)
{
return Visitable.Container();
}
public override string GetNameX()
{
return null;
}
//
// The state as we generate the iterator
//
Label move_next_ok, move_next_error;
LocalBuilder skip_finally, current_pc;
public LocalBuilder SkipFinally {
get { return skip_finally; }
}
public LocalBuilder CurrentPC {
get { return current_pc; }
}
public Block Container {
get { return OriginalMethod.Block; }
}
public GenericMethod GenericMethod {
get { return OriginalMethod.GenericMethod; }
}
public readonly Type OriginalIteratorType;
readonly IteratorStorey IteratorHost;
public enum State {
Running = -3, // Used only in CurrentPC, never stored into $PC
Uninitialized = -2,
After = -1,
Start = 0
}
public void EmitYieldBreak (ILGenerator ig, bool unwind_protect)
{
ig.Emit (unwind_protect ? OpCodes.Leave : OpCodes.Br, move_next_error);
}
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);
}
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);
}
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);
}
ArrayList resume_points;
public int AddResumePoint (ResumableStatement stmt)
{
if (resume_points == null)
resume_points = new ArrayList ();
resume_points.Add (stmt);
return resume_points.Count;
}
//
// 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 override string ContainerType {
get { return "iterator"; }
}
public override bool IsIterator {
get { return true; }
}
public override AnonymousMethodStorey Storey {
get { return IteratorHost; }
}
//
// Our constructor
//
private Iterator (CompilerContext ctx, IMethodData method, TypeContainer host, Type iterator_type, bool is_enumerable)
: base (
new ToplevelBlock (ctx, method.Block, ParametersCompiled.EmptyReadOnlyParameters, method.Block.StartLocation),
TypeManager.bool_type,
method.Location)
{
this.OriginalMethod = method;
this.OriginalIteratorType = iterator_type;
this.IsEnumerable = is_enumerable;
this.Host = host;
this.type = method.ReturnType;
IteratorHost = Block.ChangeToIterator (this, method.Block);
}
public override string GetSignatureForError ()
{
return OriginalMethod.GetSignatureForError ();
}
public override Expression DoResolve (ResolveContext ec)
{
method = new AnonymousMethodMethod (Storey,
this, Storey, null, TypeManager.system_boolean_expr,
Modifiers.PUBLIC, OriginalMethod.GetSignatureForError (),
new MemberName ("MoveNext", Location),
ParametersCompiled.EmptyReadOnlyParameters);
if (!Compatible (ec))
return null;
IteratorHost.DefineIteratorMembers ();
eclass = ExprClass.Value;
return this;
}
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);
}
}
public override Expression CreateExpressionTree (ResolveContext ec)
{
throw new NotSupportedException ("ET");
}
public static void CreateIterator (IMethodData method, TypeContainer parent, int modifiers, CompilerContext ctx)
{
bool is_enumerable;
Type iterator_type;
Type ret = method.ReturnType;
if (ret == null)
return;
if (!CheckType (ret, out iterator_type, out is_enumerable)) {
ctx.Report.Error (1624, method.Location,
"The body of `{0}' cannot be an iterator block " +
"because `{1}' is not an iterator interface type",
method.GetSignatureForError (),
TypeManager.CSharpName (ret));
return;
}
ParametersCompiled parameters = method.ParameterInfo;
for (int i = 0; i < parameters.Count; i++) {
Parameter p = parameters [i];
Parameter.Modifier mod = p.ModFlags;
if ((mod & Parameter.Modifier.ISBYREF) != 0) {
ctx.Report.Error (1623, p.Location,
"Iterators cannot have ref or out parameters");
return;
}
if (p is ArglistParameter) {
ctx.Report.Error (1636, method.Location,
"__arglist is not allowed in parameter list of iterators");
return;
}
if (parameters.Types [i].IsPointer) {
ctx.Report.Error (1637, p.Location,
"Iterators cannot have unsafe parameters or " +
"yield types");
return;
}
}
if ((modifiers & Modifiers.UNSAFE) != 0) {
ctx.Report.Error (1629, method.Location, "Unsafe code may not appear in iterators");
return;
}
Iterator iter = new Iterator (ctx, method, parent, iterator_type, is_enumerable);
iter.Storey.DefineType ();
}
static bool CheckType (Type ret, out Type original_iterator_type, out bool is_enumerable)
{
original_iterator_type = null;
is_enumerable = false;
if (ret == TypeManager.ienumerable_type) {
original_iterator_type = TypeManager.object_type;
is_enumerable = true;
return true;
}
if (ret == TypeManager.ienumerator_type) {
original_iterator_type = TypeManager.object_type;
is_enumerable = false;
return true;
}
if (!TypeManager.IsGenericType (ret))
return false;
Type[] args = TypeManager.GetTypeArguments (ret);
if (args.Length != 1)
return false;
Type gt = TypeManager.DropGenericTypeArguments (ret);
if (gt == TypeManager.generic_ienumerable_type) {
original_iterator_type = TypeManager.TypeToCoreType (args [0]);
is_enumerable = true;
return true;
}
if (gt == TypeManager.generic_ienumerator_type) {
original_iterator_type = TypeManager.TypeToCoreType (args [0]);
is_enumerable = false;
return true;
}
return false;
}
}
}