An Expression to hold a temporary value.
The LocalTemporary class is used to hold temporary values of a given type to "simulate" the expression semantics. The local variable is never captured. The local temporary is used to alter the normal flow of code generation basically it creates a local variable, and its emit instruction generates code to access this value, return its address or save its value. If `is_address' is true, then the value that we store is the address to the real value, and not the value itself. This is needed for a value type, because otherwise you just end up making a copy of the value on the stack and modifying it. You really need a pointer to the origional value so that you can modify it in that location. This Does not happen with a class because a class is a pointer -- so you always get the indirection.
Inheritance: Mono.CSharp.Expression, IMemoryLocation, IAssignMethod
Exemple #1
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        public void EmitToVariable(EmitContext ec)
        {
            var type = Expr.Type;

            if (IsByRef)
            {
                var ml = (IMemoryLocation)Expr;
                ml.AddressOf(ec, AddressOp.LoadStore);
                type = ReferenceContainer.MakeType(ec.Module, type);
            }
            else
            {
                Expr.Emit(ec);
            }

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

            Expr = variable;
        }
Exemple #2
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        public void EmitLoad(EmitContext ec, bool boxInstance)
        {
            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 (boxInstance && RequiresBoxing())
            {
                ec.Emit(OpCodes.Box, instance_type);
            }
        }
Exemple #3
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		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);
		}
Exemple #4
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		//
		// 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;
		}
Exemple #5
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		static TypeSpec EmitCallInstance (EmitContext ec, Expression instance, TypeSpec declaringType, OpCode callOpcode)
		{
			var instance_type = instance.Type;

			//
			// Push the instance expression
			//
			if ((instance_type.IsStructOrEnum && (callOpcode == OpCodes.Callvirt || (callOpcode == OpCodes.Call && declaringType.IsStruct))) ||
				instance_type.IsGenericParameter || declaringType.IsNullableType) {
				//
				// 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 ReferenceContainer.MakeType (ec.Module, instance_type);
			}

			if (instance_type.IsStructOrEnum) {
				instance.Emit (ec);
				ec.Emit (OpCodes.Box, instance_type);
				return ec.BuiltinTypes.Object;
			}

			instance.Emit (ec);
			return instance_type;
		}
Exemple #6
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		//
		// if `dup_args' is true, a copy of the arguments will be left
		// on the stack and return value will contain an array of access
		// expressions
		// NOTE: It's caller responsibility is to release temporary variables
		//
		public virtual Expression[] Emit (EmitContext ec, bool dup_args)
		{
			Expression[] temps;

			if (dup_args && Count != 0)
				temps = new Expression [Count];
			else
				temps = null;

			int i = 0;
			LocalTemporary lt;
			foreach (Argument a in args) {
				a.Emit (ec);
				if (!dup_args)
					continue;

				if (a.Expr is Constant || a.Expr is This) {
					//
					// No need to create a temporary variable for constants
					//
					temps[i] = a.Expr;
				} else {
					ec.Emit (OpCodes.Dup);
					temps[i] = lt = new LocalTemporary (a.Type);
					lt.Store (ec);
				}

				++i;
			}

			return temps;
		}
Exemple #7
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		protected override void DoEmit (EmitContext ec)
		{
			if (IsGeneral)
				ec.BeginCatchBlock (TypeManager.object_type);
			else
				ec.BeginCatchBlock (CatchType);

			if (li != null) {
				li.CreateBuilder (ec);

				//
				// Special case hoisted catch variable, we have to use a temporary variable
				// to pass via anonymous storey initialization with the value still on top
				// of the stack
				//
				if (li.HoistedVariant != null) {
					LocalTemporary lt = new LocalTemporary (li.Type);
					SymbolWriter.OpenCompilerGeneratedBlock (ec);
					lt.Store (ec);
					SymbolWriter.CloseCompilerGeneratedBlock (ec);

					// switch to assigning from the temporary variable and not from top of the stack
					assign.UpdateSource (lt);
				}
			} else {
				SymbolWriter.OpenCompilerGeneratedBlock (ec);
				ec.Emit (OpCodes.Pop);
				SymbolWriter.CloseCompilerGeneratedBlock (ec);
			}

			Block.Emit (ec);
		}
Exemple #8
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		void DoEmitStringSwitch (LocalTemporary value, EmitContext ec)
		{
			Label l_initialized = ec.DefineLabel ();

			//
			// Skip initialization when value is null
			//
			value.EmitBranchable (ec, null_target, false);

			//
			// Check if string dictionary is initialized and initialize
			//
			switch_cache_field.EmitBranchable (ec, l_initialized, true);
			string_dictionary.EmitStatement (ec);
			ec.MarkLabel (l_initialized);

			LocalTemporary string_switch_variable = new LocalTemporary (TypeManager.int32_type);

			ResolveContext rc = new ResolveContext (ec.MemberContext);

			if (TypeManager.generic_ienumerable_type != null) {
				Arguments get_value_args = new Arguments (2);
				get_value_args.Add (new Argument (value));
				get_value_args.Add (new Argument (string_switch_variable, Argument.AType.Out));
				Expression get_item = new Invocation (new MemberAccess (switch_cache_field, "TryGetValue", loc), get_value_args).Resolve (rc);
				if (get_item == null)
					return;

				//
				// A value was not found, go to default case
				//
				get_item.EmitBranchable (ec, default_target, false);
			} else {
				Arguments get_value_args = new Arguments (1);
				get_value_args.Add (new Argument (value));

				Expression get_item = new ElementAccess (switch_cache_field, get_value_args, loc).Resolve (rc);
				if (get_item == null)
					return;

				LocalTemporary get_item_object = new LocalTemporary (TypeManager.object_type);
				get_item_object.EmitAssign (ec, get_item, true, false);
				ec.Emit (OpCodes.Brfalse, default_target);

				ExpressionStatement get_item_int = (ExpressionStatement) new SimpleAssign (string_switch_variable,
					new Cast (new TypeExpression (TypeManager.int32_type, loc), get_item_object, loc)).Resolve (rc);

				get_item_int.EmitStatement (ec);
				get_item_object.Release (ec);
			}

			TableSwitchEmit (ec, string_switch_variable);
			string_switch_variable.Release (ec);
		}
		public void Emit (EmitContext ec, bool leave_copy)
		{
			if (prepared) {
				prepared_value.Emit (ec);
			} else {
				Invocation.EmitCall (ec, is_base_indexer, instance_expr, get,
					arguments, loc, false, false);
			}

			if (leave_copy) {
				ec.ig.Emit (OpCodes.Dup);
				temp = new LocalTemporary (Type);
				temp.Store (ec);
			}
		}
Exemple #10
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		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);
		}
Exemple #11
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		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;
		}
		//
		// 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);
			}
		}
Exemple #15
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		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;
		}
Exemple #16
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		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);
				}
			}
		}
Exemple #17
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		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;
			}
		}
Exemple #18
0
			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);
			}
		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);
		}
Exemple #20
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		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;
		}
Exemple #21
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        public void Emit(EmitContext ec, bool leave_copy)
        {
            bool is_volatile = false;

            if ((spec.Modifiers & Modifiers.VOLATILE) != 0)
                is_volatile = true;

            spec.MemberDefinition.SetIsUsed ();

            if (IsStatic){
                if (is_volatile)
                    ec.Emit (OpCodes.Volatile);

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

                // Optimization for build-in types
                if (TypeManager.IsStruct (type) && TypeManager.IsEqual (type, ec.MemberContext.CurrentType) && TypeManager.IsEqual (InstanceExpression.Type, type)) {
                    ec.EmitLoadFromPtr (type);
                } else {
                    var ff = spec as FixedFieldSpec;
                    if (ff != null) {
                        ec.Emit (OpCodes.Ldflda, spec);
                        ec.Emit (OpCodes.Ldflda, ff.Element);
                    } else {
                        if (is_volatile)
                            ec.Emit (OpCodes.Volatile);

                        ec.Emit (OpCodes.Ldfld, spec);
                    }
                }
            }

            if (leave_copy) {
                ec.Emit (OpCodes.Dup);
                if (!IsStatic) {
                    temp = new LocalTemporary (this.Type);
                    temp.Store (ec);
                }
            }
        }
Exemple #22
0
		//
		// 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);
		}
Exemple #23
0
        public void EmitAssign(EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
        {
            prepared = prepare_for_load;
            EmitInstance (ec, prepared);

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

            if ((spec.Modifiers & Modifiers.VOLATILE) != 0)
                ec.Emit (OpCodes.Volatile);

            spec.MemberDefinition.SetIsAssigned ();

            if (IsStatic)
                ec.Emit (OpCodes.Stsfld, spec);
            else
                ec.Emit (OpCodes.Stfld, spec);

            if (temp != null) {
                temp.Emit (ec);
                temp.Release (ec);
                temp = null;
            }
        }
Exemple #24
0
		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);
		}
Exemple #25
0
        protected void EmitInstance(EmitContext ec, bool prepare_for_load)
        {
            if (IsStatic)
                return;

            if (InstanceExpression == EmptyExpression.Null) {
                // FIXME: This should not be here at all
                SimpleName.Error_ObjectRefRequired (new ResolveContext (ec.MemberContext), loc, GetSignatureForError ());
                return;
            }

            if (TypeManager.IsValueType (InstanceExpression.Type)) {
                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.Emit (OpCodes.Dup);
        }
Exemple #26
0
        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;
            InstanceEmitter ie = new InstanceEmitter();

            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);
                    ie            = new InstanceEmitter(instance_copy, IsAddressCall(instance_copy, call_op, method.DeclaringType));

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

                    if (NullShortCircuit)
                    {
                        NullOperatorLabel = ie.NullOperatorLabel;
                    }

                    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)
                    {
                        ie = new InstanceEmitter(instance_copy, IsAddressCall(instance_copy, call_op, method.DeclaringType));
                        ie.Emit(ec);

                        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);
            }

            if (NullShortCircuit && !DuplicateArguments)
            {
                ie.EmitResultLift(ec, method.ReturnType, statement);
            }
        }
Exemple #27
0
        public void Emit(EmitContext ec, bool leave_copy)
        {
            //
            // Special case: length of single dimension array property is turned into ldlen
            //
            if (IsSingleDimensionalArrayLength ()) {
                if (!prepared)
                    EmitInstance (ec, false);
                ec.Emit (OpCodes.Ldlen);
                ec.Emit (OpCodes.Conv_I4);
                return;
            }

            Invocation.EmitCall (ec, IsBase, InstanceExpression, spec.Get, null, loc, prepared, false);

            if (leave_copy) {
                ec.Emit (OpCodes.Dup);
                if (!IsStatic) {
                    temp = new LocalTemporary (this.Type);
                    temp.Store (ec);
                }
            }
        }
Exemple #28
0
		protected void EmitConditionalAccess (EmitContext ec)
		{
			var a_expr = arguments [0].Expr;

			var des = a_expr as DynamicExpressionStatement;
			if (des != null) {
				des.EmitConditionalAccess (ec);
			}

			if (HasConditionalAccess ()) {
				var NullOperatorLabel = ec.DefineLabel ();

				if (ExpressionAnalyzer.IsInexpensiveLoad (a_expr)) {
					a_expr.Emit (ec);
				} else {
					var lt = new LocalTemporary (a_expr.Type);
					lt.EmitAssign (ec, a_expr, true, false);

					Arguments [0].Expr = lt;
				}

				ec.Emit (OpCodes.Brtrue_S, NullOperatorLabel);

				if (!ec.ConditionalAccess.Statement) {
					if (ec.ConditionalAccess.Type.IsNullableType)
						Nullable.LiftedNull.Create (ec.ConditionalAccess.Type, Location.Null).Emit (ec);
					else
						ec.EmitNull ();
				}

				ec.Emit (OpCodes.Br, ec.ConditionalAccess.EndLabel);
				ec.MarkLabel (NullOperatorLabel);

				return;
			}

			if (a_expr.HasConditionalAccess ()) {
				var lt = new LocalTemporary (a_expr.Type);
				lt.EmitAssign (ec, a_expr, false, false);

				Arguments [0].Expr = lt;
			}
		}
Exemple #29
0
        //
        // Implements the IAssignMethod interface for assignments
        //
        public void EmitAssign(EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
        {
            Expression my_source = source;

            if (prepare_for_load) {
                prepared = true;
                source.Emit (ec);

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

            Arguments args = new Arguments (1);
            args.Add (new Argument (my_source));

            Invocation.EmitCall (ec, IsBase, InstanceExpression, spec.Set, args, loc, false, prepared);

            if (temp != null) {
                temp.Emit (ec);
                temp.Release (ec);
            }
        }
Exemple #30
0
		public void EmitLoad (EmitContext ec, bool boxInstance)
		{
			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 (boxInstance && RequiresBoxing ()) {
				ec.Emit (OpCodes.Box, instance_type);
			}
		}
Exemple #31
0
		protected override void DoEmit (EmitContext ec)
		{
			if (CatchType != null)
				ec.BeginCatchBlock (CatchType);
			else
				ec.BeginCatchBlock (TypeManager.object_type);

			if (VarBlock != null)
				VarBlock.Emit (ec);

			if (Name != null) {
				// TODO: Move to resolve
				LocalVariableReference lvr = new LocalVariableReference (Block, Name, loc);
				lvr.Resolve (new ResolveContext (ec.MemberContext));
				
				// Only to make verifier happy
				if (TypeManager.IsGenericParameter (lvr.Type))
					ec.Emit (OpCodes.Unbox_Any, lvr.Type);

				Expression source;
				if (lvr.IsHoisted) {
					LocalTemporary lt = new LocalTemporary (lvr.Type);
					lt.Store (ec);
					source = lt;
				} else {
					// Variable is at the top of the stack
					source = EmptyExpression.Null;
				}

				lvr.EmitAssign (ec, source, false, false);
			} else
				ec.Emit (OpCodes.Pop);

			Block.Emit (ec);
		}
Exemple #32
0
		//
		// if `dup_args' is true, a copy of the arguments will be left
		// on the stack. If `dup_args' is true, you can specify `this_arg'
		// which will be duplicated before any other args. Only EmitCall
		// should be using this interface.
		//
		public void Emit (EmitContext ec, bool dup_args, LocalTemporary this_arg)
		{
			LocalTemporary[] temps = null;

			if (dup_args && Count != 0)
				temps = new LocalTemporary [Count];

			if (reordered != null && Count > 1) {
				foreach (NamedArgument na in reordered)
					na.EmitAssign (ec);
			}

			int i = 0;
			foreach (Argument a in args) {
				a.Emit (ec);
				if (dup_args) {
					ec.Emit (OpCodes.Dup);
					(temps [i++] = new LocalTemporary (a.Type)).Store (ec);
				}
			}

			if (dup_args) {
				if (this_arg != null)
					this_arg.Emit (ec);

				for (i = 0; i < temps.Length; i++) {
					temps[i].Emit (ec);
					temps[i].Release (ec);
				}
			}
		}
Exemple #33
0
				public Dispose (TemporaryVariable variable, LocalTemporary dispose, Expression expr, Statement statement, Location loc)
					: base (expr, statement, loc)
				{
					base.local_copy = variable;
					this.dispose = dispose;
				}
Exemple #34
0
        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.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);
                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);
        }
Exemple #35
0
        protected override Expression DoResolve(ResolveContext rc)
        {
            var src = source.Resolve(rc);

            if (src == null)
            {
                return(null);
            }

            if (InternalType.HasNoType(src.Type))
            {
                rc.Report.Error(8131, source.Location, "Deconstruct assignment requires an expression with a type on the right-hand-side");
                return(null);
            }

            var src_type = src.Type;

            if (src_type.IsTupleType)
            {
                int target_count;

                if (targetExprs == null)
                {
                    target_count = variables.Count;
                    targetExprs  = new List <Expression> (target_count);
                }
                else
                {
                    target_count = targetExprs.Count;
                }

                if (src_type.Arity != target_count)
                {
                    rc.Report.Error(8132, loc, "Cannot deconstruct a tuple of `{0}' elements into `{1}' variables",
                                    src_type.Arity.ToString(CultureInfo.InvariantCulture), target_count.ToString(CultureInfo.InvariantCulture));
                    return(null);
                }

                var tupleLiteral = src as TupleLiteral;
                if (tupleLiteral == null && !ExpressionAnalyzer.IsInexpensiveLoad(src))
                {
                    var expr_variable = LocalVariable.CreateCompilerGenerated(source.Type, rc.CurrentBlock, loc);
                    source   = new CompilerAssign(expr_variable.CreateReferenceExpression(rc, loc), source, loc);
                    instance = expr_variable.CreateReferenceExpression(rc, loc);
                }

                var element_srcs = new List <Expression> ();
                var src_names    = new List <string> ();
                for (int i = 0; i < target_count; ++i)
                {
                    var element_src = tupleLiteral == null ? new MemberAccess(instance, NamedTupleSpec.GetElementPropertyName(i)) : tupleLiteral.Elements [i].Expr;
                    element_srcs.Add(element_src);
                    if (element_src is VariableReference)
                    {
                        src_names.Add((element_src as VariableReference)?.Name);
                    }
                }

                for (int i = 0; i < target_count; ++i)
                {
                    var tle = src_type.TypeArguments [i];

                    if (variables != null)
                    {
                        var variable = variables [i].Variable;

                        if (variable.Type == InternalType.Discard)
                        {
                            variables [i] = null;
                            targetExprs.Add(EmptyExpressionStatement.Instance);
                            continue;
                        }

                        var variable_type = variables [i].TypeExpression;

                        targetExprs.Add(new LocalVariableReference(variable, variable.Location));

                        if (variable_type is VarExpr)
                        {
                            if (InternalType.HasNoType(tle))
                            {
                                rc.Report.Error(8130, Location, "Cannot infer the type of implicitly-typed deconstruction variable `{0}'", variable.Name);
                                tle = InternalType.ErrorType;
                            }

                            variable.Type = tle;
                        }
                        else
                        {
                            variable.Type = variable_type.ResolveAsType(rc);
                        }

                        variable.PrepareAssignmentAnalysis((BlockContext)rc);
                    }

                    var element_target = (targetExprs [i] as SimpleName)?.LookupNameExpression(rc, MemberLookupRestrictions.None);

                    if (element_target != null && src_names.Contains((element_target as VariableReference)?.Name))
                    {
                        var tempType = element_target.Resolve(rc).Type;

                        var temp = new LocalTemporary(tempType);
                        tempExprs.Add(new SimpleAssign(temp, element_srcs [i]).Resolve(rc));
                        targetExprs [i] = new SimpleAssign(targetExprs [i], temp).Resolve(rc);
                    }
                    else
                    {
                        targetExprs [i] = new SimpleAssign(targetExprs [i], element_srcs [i]).Resolve(rc);
                    }
                }

                eclass = ExprClass.Value;

                // TODO: The type is same only if there is no target element conversion
                // var res = (/*byte*/ b, /*short*/ s) = (2, 4);
                type = src.Type;
                return(this);
            }

            if (src_type.BuiltinType == BuiltinTypeSpec.Type.Dynamic)
            {
                rc.Report.Error(8133, loc, "Cannot deconstruct dynamic objects");
                return(null);
            }

            /*
             * var args = new Arguments (targetExprs.Count);
             * foreach (var t in targetExprs) {
             *      args.Add (new Argument (t, Argument.AType.Out));
             * }
             *
             * var invocation = new Invocation (new MemberAccess (src, "Deconstruct"), args);
             * var res = invocation.Resolve (rc);
             */

            throw new NotImplementedException("Custom deconstruct");
        }