C# CSharp.LocalTemporary类代码示例

		//
		// source is ignored, because we already have a copy of it from the
		// LValue resolution and we have already constructed a pre-cached
		// version of the arguments (ea.set_arguments);
		//
		public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
		{
			prepared = prepare_for_load;
			Expression value = set_expr;

			if (prepared) {
				Invocation.EmitCall (ec, is_base_indexer, instance_expr, get,
					arguments, loc, true, false);

				prepared_value = new LocalTemporary (type);
				prepared_value.Store (ec);
				source.Emit (ec);
				prepared_value.Release (ec);

				if (leave_copy) {
					ec.ig.Emit (OpCodes.Dup);
					temp = new LocalTemporary (Type);
					temp.Store (ec);
				}
			} else if (leave_copy) {
				temp = new LocalTemporary (Type);
				source.Emit (ec);
				temp.Store (ec);
				value = temp;
			}
			
			if (!prepared)
				arguments.Add (new Argument (value));

			Invocation.EmitCall (ec, is_base_indexer, instance_expr, set, arguments, loc, false, prepared);
			
			if (temp != null) {
				temp.Emit (ec);
				temp.Release (ec);
			}
		}

		public void EmitPredefined (EmitContext ec, MethodSpec method, Arguments Arguments, bool statement = false, Location? loc = null)
		{
			Expression instance_copy = null;

			if (!HasAwaitArguments && ec.HasSet (BuilderContext.Options.AsyncBody)) {
				HasAwaitArguments = Arguments != null && Arguments.ContainsEmitWithAwait ();
				if (HasAwaitArguments && InstanceExpressionOnStack) {
					throw new NotSupportedException ();
				}
			}

			OpCode call_op;
			LocalTemporary lt = null;

			if (method.IsStatic) {
				call_op = OpCodes.Call;
			} else {
				call_op = IsVirtualCallRequired (InstanceExpression, method) ? OpCodes.Callvirt : OpCodes.Call;

				if (HasAwaitArguments) {
					instance_copy = InstanceExpression.EmitToField (ec);
					var ie = new InstanceEmitter (instance_copy, IsAddressCall (instance_copy, call_op, method.DeclaringType));

					if (Arguments == null) {
						ie.EmitLoad (ec, true);
					}
				} else if (!InstanceExpressionOnStack) {
					var ie = new InstanceEmitter (InstanceExpression, IsAddressCall (InstanceExpression, call_op, method.DeclaringType));
					ie.Emit (ec, ConditionalAccess);

					if (DuplicateArguments) {
						ec.Emit (OpCodes.Dup);
						if (Arguments != null && Arguments.Count != 0) {
							lt = new LocalTemporary (ie.GetStackType (ec));
							lt.Store (ec);
							instance_copy = lt;
						}
					}
				}
			}

			if (Arguments != null && !InstanceExpressionOnStack) {
				EmittedArguments = Arguments.Emit (ec, DuplicateArguments, HasAwaitArguments);
				if (EmittedArguments != null) {
					if (instance_copy != null) {
						var ie = new InstanceEmitter (instance_copy, IsAddressCall (instance_copy, call_op, method.DeclaringType));
						ie.Emit (ec, ConditionalAccess);

						if (lt != null)
							lt.Release (ec);
					}

					EmittedArguments.Emit (ec);
				}
			}

			if (call_op == OpCodes.Callvirt && (InstanceExpression.Type.IsGenericParameter || InstanceExpression.Type.IsStructOrEnum)) {
				ec.Emit (OpCodes.Constrained, InstanceExpression.Type);
			}

			if (loc != null) {
				//
				// Emit explicit sequence point for expressions like Foo.Bar () to help debugger to
				// break at right place when LHS expression can be stepped-into
				//
				ec.MarkCallEntry (loc.Value);
			}

			//
			// Set instance expression to actual result expression. When it contains await it can be
			// picked up by caller
			//
			InstanceExpression = instance_copy;

			if (method.Parameters.HasArglist) {
				var varargs_types = GetVarargsTypes (method, Arguments);
				ec.Emit (call_op, method, varargs_types);
			} else {
				//
				// If you have:
				// this.DoFoo ();
				// and DoFoo is not virtual, you can omit the callvirt,
				// because you don't need the null checking behavior.
				//
				ec.Emit (call_op, method);
			}

			// 
			// Pop the return value if there is one and stack should be empty
			//
			if (statement && method.ReturnType.Kind != MemberKind.Void)
				ec.Emit (OpCodes.Pop);
		}

		public void EmitAssign (EmitContext ec)
		{
			var type = Expr.Type;
			if (IsByRef) {
				var ml = (IMemoryLocation) Expr;
				ml.AddressOf (ec, AddressOp.Load);
				type = ReferenceContainer.MakeType (type);
			} else {
				Expr.Emit (ec);
			}

			variable = new LocalTemporary (type);
			variable.Store (ec);

			Expr = variable;
		}

		public void EmitPredefined (EmitContext ec, MethodSpec method, Arguments Arguments)
		{
			Expression instance_copy = null;

			if (!HasAwaitArguments && ec.HasSet (BuilderContext.Options.AsyncBody)) {
				HasAwaitArguments = Arguments != null && Arguments.ContainsEmitWithAwait ();
				if (HasAwaitArguments && InstanceExpressionOnStack) {
					throw new NotSupportedException ();
				}
			}

			OpCode call_op;
			LocalTemporary lt = null;

			if (method.IsStatic) {
				call_op = OpCodes.Call;
			} else {
				if (IsVirtualCallRequired (InstanceExpression, method)) {
					call_op = OpCodes.Callvirt;
				} else {
					call_op = OpCodes.Call;
				}

				if (HasAwaitArguments) {
					instance_copy = InstanceExpression.EmitToField (ec);
					if (Arguments == null)
						EmitCallInstance (ec, instance_copy, method.DeclaringType, call_op);
				} else if (!InstanceExpressionOnStack) {
					var instance_on_stack_type = EmitCallInstance (ec, InstanceExpression, method.DeclaringType, call_op);

					if (DuplicateArguments) {
						ec.Emit (OpCodes.Dup);
						if (Arguments != null && Arguments.Count != 0) {
							lt = new LocalTemporary (instance_on_stack_type);
							lt.Store (ec);
							instance_copy = lt;
						}
					}
				}
			}

			if (Arguments != null && !InstanceExpressionOnStack) {
				EmittedArguments = Arguments.Emit (ec, DuplicateArguments, HasAwaitArguments);
				if (EmittedArguments != null) {
					if (instance_copy != null) {
						EmitCallInstance (ec, instance_copy, method.DeclaringType, call_op);

						if (lt != null)
							lt.Release (ec);
					}

					EmittedArguments.Emit (ec);
				}
			}

			if (call_op == OpCodes.Callvirt && (InstanceExpression.Type.IsGenericParameter || InstanceExpression.Type.IsStruct)) {
				ec.Emit (OpCodes.Constrained, InstanceExpression.Type);
			}

			//
			// Set instance expression to actual result expression. When it contains await it can be
			// picked up by caller
			//
			InstanceExpression = instance_copy;

			if (method.Parameters.HasArglist) {
				var varargs_types = GetVarargsTypes (method, Arguments);
				ec.Emit (call_op, method, varargs_types);
				return;
			}

			//
			// If you have:
			// this.DoFoo ();
			// and DoFoo is not virtual, you can omit the callvirt,
			// because you don't need the null checking behavior.
			//
			ec.Emit (call_op, method);
		}

		//
		// if `dup_args' is true or any of arguments contains await.
		// A copy of all arguments will be returned to the caller
		//
		public virtual Arguments Emit (EmitContext ec, bool dup_args, bool prepareAwait)
		{
			List<Argument> dups;

			if ((dup_args && Count != 0) || prepareAwait)
				dups = new List<Argument> (Count);
			else
				dups = null;

			LocalTemporary lt;
			foreach (Argument a in args) {
				if (prepareAwait) {
					dups.Add (a.EmitToField (ec, true));
					continue;
				}
				
				a.Emit (ec);

				if (!dup_args) {
					continue;
				}

				if (a.Expr.IsSideEffectFree) {
					//
					// No need to create a temporary variable for side effect free expressions. I assume
					// all side-effect free expressions are cheap, this has to be tweaked when we become
					// more aggressive on detection
					//
					dups.Add (a);
				} else {
					ec.Emit (OpCodes.Dup);

					// TODO: Release local temporary on next Emit
					// Need to add a flag to argument to indicate this
					lt = new LocalTemporary (a.Type);
					lt.Store (ec);

					dups.Add (new Argument (lt, a.ArgType));
				}
			}

			if (dups != null)
				return new Arguments (dups);

			return null;
		}

		protected override void DoEmit (EmitContext ec)
		{
			//
			// Needed to emit anonymous storey initialization
			// Otherwise it does not contain any statements for now
			//
			block.Emit (ec);

			default_target = ec.DefineLabel ();
			null_target = ec.DefineLabel ();

			// Store variable for comparission purposes
			// TODO: Don't duplicate non-captured VariableReference
			LocalTemporary value;
			if (HaveUnwrap) {
				value = new LocalTemporary (SwitchType);
				unwrap.EmitCheck (ec);
				ec.Emit (OpCodes.Brfalse, null_target);
				new_expr.Emit (ec);
				value.Store (ec);
			} else if (!is_constant) {
				value = new LocalTemporary (SwitchType);
				new_expr.Emit (ec);
				value.Store (ec);
			} else
				value = null;

			//
			// Setup the codegen context
			//
			Label old_end = ec.LoopEnd;
			Switch old_switch = ec.Switch;
			
			ec.LoopEnd = ec.DefineLabel ();
			ec.Switch = this;

			// Emit Code.
			if (is_constant) {
				if (constant_section != null)
					constant_section.Block.Emit (ec);
			} else if (string_dictionary != null) {
				DoEmitStringSwitch (value, ec);
			} else {
				TableSwitchEmit (ec, value);
			}

			if (value != null)
				value.Release (ec);

			// Restore context state. 
			ec.MarkLabel (ec.LoopEnd);

			//
			// Restore the previous context
			//
			ec.LoopEnd = old_end;
			ec.Switch = old_switch;
		}

		//
		// Initializes all hoisted variables
		//
		public void EmitStoreyInstantiation (EmitContext ec)
		{
			// There can be only one instance variable for each storey type
			if (Instance != null)
				throw new InternalErrorException ();

			SymbolWriter.OpenCompilerGeneratedBlock (ec);

			//
			// Create an instance of a storey
			//
			var storey_type_expr = CreateStoreyTypeExpression (ec);

			ResolveContext rc = new ResolveContext (ec.MemberContext);
			Expression e = new New (storey_type_expr, null, Location).Resolve (rc);
			e.Emit (ec);

			Instance = new LocalTemporary (storey_type_expr.Type);
			Instance.Store (ec);

			EmitHoistedFieldsInitialization (ec);

			SymbolWriter.DefineScopeVariable (ID, Instance.Builder);
			SymbolWriter.CloseCompilerGeneratedBlock (ec);
		}

		public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
		{
			FieldAttributes fa = FieldInfo.Attributes;
			bool is_static = (fa & FieldAttributes.Static) != 0;
			bool is_readonly = (fa & FieldAttributes.InitOnly) != 0;
			ILGenerator ig = ec.ig;

			if (is_readonly && !ec.IsConstructor){
				Report_AssignToReadonly (source);
				return;
			}

			prepared = prepare_for_load;
			EmitInstance (ec, prepared);

			source.Emit (ec);
			if (leave_copy) {
				ec.ig.Emit (OpCodes.Dup);
				if (!FieldInfo.IsStatic) {
					temp = new LocalTemporary (this.Type);
					temp.Store (ec);
				}
			}

			FieldBase f = TypeManager.GetField (FieldInfo);
			if (f != null){
				if ((f.ModFlags & Modifiers.VOLATILE) != 0)
					ig.Emit (OpCodes.Volatile);
					
				f.SetAssigned ();
			}

			if (is_static)
				ig.Emit (OpCodes.Stsfld, GetConstructedFieldInfo ());
			else
				ig.Emit (OpCodes.Stfld, GetConstructedFieldInfo ());
			
			if (temp != null) {
				temp.Emit (ec);
				temp.Release (ec);
				temp = null;
			}
		}

		public void EmitPredefined (EmitContext ec, MethodSpec method, Arguments Arguments, Location? loc = null)
		{
			Expression instance_copy = null;

			if (!HasAwaitArguments && ec.HasSet (BuilderContext.Options.AsyncBody)) {
				HasAwaitArguments = Arguments != null && Arguments.ContainsEmitWithAwait ();
				if (HasAwaitArguments && InstanceExpressionOnStack) {
					throw new NotSupportedException ();
				}
			}

			OpCode call_op;
			LocalTemporary lt = null;

			if (method.IsStatic) {
				call_op = OpCodes.Call;
			} else {
				if (IsVirtualCallRequired (InstanceExpression, method)) {
					call_op = OpCodes.Callvirt;
				} else {
					call_op = OpCodes.Call;
				}

				if (HasAwaitArguments) {
					instance_copy = InstanceExpression.EmitToField (ec);
					if (Arguments == null)
						EmitCallInstance (ec, instance_copy, method.DeclaringType, call_op);
				} else if (!InstanceExpressionOnStack) {
					var instance_on_stack_type = EmitCallInstance (ec, InstanceExpression, method.DeclaringType, call_op);

					if (DuplicateArguments) {
						ec.Emit (OpCodes.Dup);
						if (Arguments != null && Arguments.Count != 0) {
							lt = new LocalTemporary (instance_on_stack_type);
							lt.Store (ec);
							instance_copy = lt;
						}
					}
				}
			}

			if (Arguments != null && !InstanceExpressionOnStack) {
				EmittedArguments = Arguments.Emit (ec, DuplicateArguments, HasAwaitArguments);
				if (EmittedArguments != null) {
					if (instance_copy != null) {
						EmitCallInstance (ec, instance_copy, method.DeclaringType, call_op);

						if (lt != null)
							lt.Release (ec);
					}

					EmittedArguments.Emit (ec);
				}
			}

			if (call_op == OpCodes.Callvirt && (InstanceExpression.Type.IsGenericParameter || InstanceExpression.Type.IsStruct)) {
				ec.Emit (OpCodes.Constrained, InstanceExpression.Type);
			}

			if (loc != null) {
				//
				// Emit explicit sequence point for expressions like Foo.Bar () to help debugger to
				// break at right place when LHS expression can be stepped-into
				//
				// TODO: The list is probably not comprehensive, need to do more testing
				//
				if (InstanceExpression is PropertyExpr || InstanceExpression is Invocation || InstanceExpression is IndexerExpr ||
					InstanceExpression is New || InstanceExpression is DelegateInvocation)
					ec.Mark (loc.Value);
			}

			//
			// Set instance expression to actual result expression. When it contains await it can be
			// picked up by caller
			//
			InstanceExpression = instance_copy;

			if (method.Parameters.HasArglist) {
				var varargs_types = GetVarargsTypes (method, Arguments);
				ec.Emit (call_op, method, varargs_types);
				return;
			}

			//
			// If you have:
			// this.DoFoo ();
			// and DoFoo is not virtual, you can omit the callvirt,
			// because you don't need the null checking behavior.
			//
			ec.Emit (call_op, method);
		}

		protected void EmitInstance (EmitContext ec, bool prepare_for_load)
		{
			if (IsStatic)
				return;

			if (InstanceExpression == EmptyExpression.Null) {
				SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
				return;
			}

			if (InstanceExpression.Type.IsValueType) {
				if (InstanceExpression is IMemoryLocation) {
					((IMemoryLocation) InstanceExpression).AddressOf (ec, AddressOp.LoadStore);
				} else {
					LocalTemporary t = new LocalTemporary (InstanceExpression.Type);
					InstanceExpression.Emit (ec);
					t.Store (ec);
					t.AddressOf (ec, AddressOp.Store);
				}
			} else
				InstanceExpression.Emit (ec);

			if (prepare_for_load)
				ec.ig.Emit (OpCodes.Dup);
		}

		public void Emit (EmitContext ec, bool leave_copy)
		{
			ILGenerator ig = ec.ig;
			bool is_volatile = false;

			FieldBase f = TypeManager.GetField (FieldInfo);
			if (f != null){
				if ((f.ModFlags & Modifiers.VOLATILE) != 0)
					is_volatile = true;

				f.SetMemberIsUsed ();
			}
			
			if (FieldInfo.IsStatic){
				if (is_volatile)
					ig.Emit (OpCodes.Volatile);

				ig.Emit (OpCodes.Ldsfld, GetConstructedFieldInfo ());
			} else {
				if (!prepared)
					EmitInstance (ec, false);

				IFixedBuffer ff = AttributeTester.GetFixedBuffer (FieldInfo);
				if (ff != null) {
					ig.Emit (OpCodes.Ldflda, GetConstructedFieldInfo ());
					ig.Emit (OpCodes.Ldflda, ff.Element);
				} else {
					if (is_volatile)
						ig.Emit (OpCodes.Volatile);

					ig.Emit (OpCodes.Ldfld, GetConstructedFieldInfo ());
				}
			}

			if (leave_copy) {
				ec.ig.Emit (OpCodes.Dup);
				if (!FieldInfo.IsStatic) {
					temp = new LocalTemporary (this.Type);
					temp.Store (ec);
				}
			}
		}

		public void EmitLoad (EmitContext ec)
		{
			var instance_type = instance.Type;

			//
			// Push the instance expression
			//
			if (addressRequired) {
				//
				// If the expression implements IMemoryLocation, then
				// we can optimize and use AddressOf on the
				// return.
				//
				// If not we have to use some temporary storage for
				// it.
				var iml = instance as IMemoryLocation;
				if (iml != null) {
					iml.AddressOf (ec, AddressOp.Load);
				} else {
					LocalTemporary temp = new LocalTemporary (instance_type);
					instance.Emit (ec);
					temp.Store (ec);
					temp.AddressOf (ec, AddressOp.Load);
				}

				return;
			}

			instance.Emit (ec);

			// Only to make verifier happy
			if (instance_type.IsGenericParameter && !(instance is This) && TypeSpec.IsReferenceType (instance_type)) {
				ec.Emit (OpCodes.Box, instance_type);
			} else if (instance_type.IsStructOrEnum) {
				ec.Emit (OpCodes.Box, instance_type);
			}
		}

		//
		// Initializes all hoisted variables
		//
		public void EmitStoreyInstantiation (EmitContext ec)
		{
			// There can be only one instance variable for each storey type
			if (Instance != null)
				throw new InternalErrorException ();

			SymbolWriter.OpenCompilerGeneratedBlock (ec.ig);

			//
			// Create an instance of storey type
			//
			Expression storey_type_expr;
			if (is_generic) {
				//
				// Use current method type parameter (MVAR) for top level storey only. All
				// nested storeys use class type parameter (VAR)
				//
				TypeParameter[] tparams = ec.CurrentAnonymousMethod != null && ec.CurrentAnonymousMethod.Storey != null ?
					ec.CurrentAnonymousMethod.Storey.TypeParameters :
					ec.CurrentTypeParameters;

				TypeArguments targs = new TypeArguments ();

				if (tparams.Length < CountTypeParameters) {
					TypeParameter[] parent_tparams = ec.MemberContext.CurrentTypeDefinition.TypeParameters;
					for (int i = 0; i < parent_tparams.Length; ++i)
						targs.Add (new TypeParameterExpr (parent_tparams[i], Location));
				}
				
				for (int i = 0; i < tparams.Length; ++i)
					targs.Add (new TypeParameterExpr (tparams[i], Location));

				storey_type_expr = new GenericTypeExpr (TypeBuilder, targs, Location);
			} else {
				storey_type_expr = new TypeExpression (TypeBuilder, Location);
			}

			ResolveContext rc = new ResolveContext (this);
			Expression e = new New (storey_type_expr, null, Location).Resolve (rc);
			e.Emit (ec);

			Instance = new LocalTemporary (storey_type_expr.Type);
			Instance.Store (ec);

			EmitHoistedFieldsInitialization (ec);

			SymbolWriter.DefineScopeVariable (ID, Instance.Builder);
			SymbolWriter.CloseCompilerGeneratedBlock (ec.ig);
		}

		public override bool Emit (EmitContext ec, IMemoryLocation target)
		{
			bool left_on_stack = base.Emit (ec, target);

			if (initializers.IsEmpty)
				return left_on_stack;

			LocalTemporary temp = target as LocalTemporary;
			if (temp == null) {
				if (!left_on_stack) {
					VariableReference vr = target as VariableReference;
					
					// FIXME: This still does not work correctly for pre-set variables
					if (vr != null && vr.IsRef)
						target.AddressOf (ec, AddressOp.Load);

					((Expression) target).Emit (ec);
					left_on_stack = true;
				}

				temp = new LocalTemporary (type);
			}

			instance = temp;
			if (left_on_stack)
				temp.Store (ec);

			initializers.Emit (ec);

			if (left_on_stack) {
				temp.Emit (ec);
				temp.Release (ec);
			}

			return left_on_stack;
		}

			public override bool Resolve (BlockContext ec)
			{
				bool is_dynamic = expr.Type == InternalType.Dynamic;
				if (is_dynamic)
					expr = Convert.ImplicitConversionRequired (ec, expr, TypeManager.ienumerable_type, loc);

				var get_enumerator_mg = ResolveGetEnumerator (ec);
				if (get_enumerator_mg == null) {
					return false;
				}

				var get_enumerator = get_enumerator_mg.BestCandidate;
				var enumerator = new TemporaryVariable (get_enumerator.ReturnType, loc);
				enumerator.Resolve (ec);

				// Prepare bool MoveNext ()
				var move_next_mg = ResolveMoveNext (ec, get_enumerator);
				if (move_next_mg == null) {
					return false;
				}

				move_next_mg.InstanceExpression = enumerator;

				// Prepare ~T~ Current { get; }
				var current_prop = ResolveCurrent (ec, get_enumerator);
				if (current_prop == null) {
					return false;
				}

				var current_pe = new PropertyExpr (current_prop, loc) { InstanceExpression = enumerator }.Resolve (ec);
				if (current_pe == null)
					return false;

				VarExpr ve = var_type as VarExpr;
				if (ve != null) {
					// Infer implicitly typed local variable from foreach enumerable type
					var_type = new TypeExpression (current_pe.Type, var_type.Location);
				}

				var_type = var_type.ResolveAsTypeTerminal (ec, false);
				if (var_type == null)
					return false;

				var init = new Invocation (get_enumerator_mg, null);
				init.Resolve (ec);

				statement = new While (new BooleanExpression (new Invocation (move_next_mg, null)),
					new Body (var_type.Type, variable, current_pe, statement, loc), loc);

				var enum_type = enumerator.Type;

				//
				// Add Dispose method call when enumerator can be IDisposable
				//
				if (!enumerator.Type.ImplementsInterface (TypeManager.idisposable_type)) {
					if (!enum_type.IsSealed && !TypeManager.IsValueType (enum_type)) {
						//
						// Runtime Dispose check
						//
						var tv = new LocalTemporary (TypeManager.idisposable_type);
						statement = new Dispose (enumerator, tv, init, statement, loc);
					} else {
						//
						// No Dispose call needed
						//
						this.init = new SimpleAssign (enumerator, init);
						this.init.Resolve (ec);
					}
				} else {
					//
					// Static Dispose check
					//
					statement = new Dispose (enumerator, null, init, statement, loc);
				}

				return statement.Resolve (ec);
			}