CompileToMethod 无法编译常量“<some value>”，因为它是一个非常重要的值，例如活动对象

Question

我正在尝试使用名为 EvaluateOnCondition 的方法创建具有 Reflection.Emit 的类型。我用 Linq Expressions 生成方法的主体，我想将表达式的 IL 注入 EvaluateOnCondition 使用 CompileToMethod 方法 LambdaExpression，但是当我执行 CompileToMethod 方法时，我得到了以下错误：

CompileToMethod cannot compile constant 'some value' because it is a non-trivial value, such as a live object. Instead, create an expression tree that can construct this value.

这就是我想要做的：

MethodBuilder evaluateOnCondition = tb.DefineMethod("EvaluateOnCondition", MethodAttributes.Public | MethodAttributes.Static, typeof(bool), new[] { typeof(object), typeof(object) });
onCondition.CompileToMethod(evaluateOnCondition); // throw the error

onCondition 变量是一个 LambdaExpression，是用 Linq 表达式创建的比较条件，表示以下伪代码：obj1.prop1 == obj2.prop1

这是我的 StackTrace：

   at System.Linq.Expressions.Compiler.BoundConstants.EmitCacheConstants(LambdaCompiler lc)
   at System.Linq.Expressions.Compiler.LambdaCompiler..ctor(AnalyzedTree tree, LambdaExpression lambda, MethodBuilder method)
   at System.Linq.Expressions.Compiler.LambdaCompiler.Compile(LambdaExpression lambda, MethodBuilder method, DebugInfoGenerator debugInfoGenerator)
   at System.Linq.Expressions.LambdaExpression.CompileToMethodInternal(MethodBuilder method, DebugInfoGenerator debugInfoGenerator)
   at System.Linq.Expressions.LambdaExpression.CompileToMethod(MethodBuilder method)
   at Integra.Space.Language.Runtime.LanguageTypeBuilder.CreateEqualsMethod(TypeBuilder tb, Type parentType, Type typeOtherSource, Boolean isSecondSource, LambdaExpression onCondition) in C:\Users\Oscar\Documents\GitHubVisualStudio\Integra.Space.Language\Integra.Space.Language\Runtime\TypeBuilders\LanguageTypeBuilder.cs:line 343
   at Integra.Space.Language.Runtime.LanguageTypeBuilder.CreateTypeBuilder(List`1 listOfFields, Type parentType, Boolean overrideGetHashCodeMethod, Boolean overrideEquals, Type typeOtherSource, Boolean isSecondSource, LambdaExpression onCondition) in C:\Users\Oscar\Documents\GitHubVisualStudio\Integra.Space.Language\Integra.Space.Language\Runtime\TypeBuilders\LanguageTypeBuilder.cs:line 165
   at Integra.Space.Language.Runtime.LanguageTypeBuilder.CompileExtractedEventDataComparerTypeForJoin(Type parentType, Type typeOfTheOtherSource, Boolean isSecondSource, LambdaExpression onCondition) in C:\Users\Oscar\Documents\GitHubVisualStudio\Integra.Space.Language\Integra.Space.Language\Runtime\TypeBuilders\LanguageTypeBuilder.cs:line 92
   at Integra.Space.Language.Runtime.ObservableConstructor.CreateProjectionExpression(PlanNode plans) in C:\Users\Oscar\Documents\GitHubVisualStudio\Integra.Space.Language\Integra.Space.Language\Runtime\ObservableConstructor.cs:line 3033
   at Integra.Space.Language.Runtime.ObservableConstructor.CreateExpressionNode(PlanNode actualNode, Expression leftNode, Expression rightNode) in C:\Users\Oscar\Documents\GitHubVisualStudio\Integra.Space.Language\Integra.Space.Language\Runtime\ObservableConstructor.cs:line 358
   at Integra.Space.Language.Runtime.ObservableConstructor.GenerateExpressionTree(PlanNode plan) in C:\Users\Oscar\Documents\GitHubVisualStudio\Integra.Space.Language\Integra.Space.Language\Runtime\ObservableConstructor.cs:line 304
   at Integra.Space.Language.Runtime.ObservableConstructor.GenerateExpressionTree(PlanNode plan) in C:\Users\Oscar\Documents\GitHubVisualStudio\Integra.Space.Language\Integra.Space.Language\Runtime\ObservableConstructor.cs:line 313
   at Integra.Space.Language.Runtime.ObservableConstructor.GenerateExpressionTree(PlanNode plan) in C:\Users\Oscar\Documents\GitHubVisualStudio\Integra.Space.Language\Integra.Space.Language\Runtime\ObservableConstructor.cs:line 299
   at Integra.Space.Language.Runtime.ObservableConstructor.GenerateExpressionTree(PlanNode plan) in C:\Users\Oscar\Documents\GitHubVisualStudio\Integra.Space.Language\Integra.Space.Language\Runtime\ObservableConstructor.cs:line 299
   at Integra.Space.Language.Runtime.ObservableConstructor.GenerateExpressionTree(PlanNode plan) in C:\Users\Oscar\Documents\GitHubVisualStudio\Integra.Space.Language\Integra.Space.Language\Runtime\ObservableConstructor.cs:line 313
   at Integra.Space.Language.Runtime.ObservableConstructor.GenerateExpressionTree(PlanNode plan) in C:\Users\Oscar\Documents\GitHubVisualStudio\Integra.Space.Language\Integra.Space.Language\Runtime\ObservableConstructor.cs:line 313
   at Integra.Space.Language.Runtime.ObservableConstructor.CreateObservableJoin(PlanNode actualNode) in C:\Users\Oscar\Documents\GitHubVisualStudio\Integra.Space.Language\Integra.Space.Language\Runtime\ObservableConstructor.cs:line 936

onCondition 变量的调试视图

.Block(System.Boolean $variable) {
    .Try {
        .Block() {
            .If (
                True
            ) {
                .Call System.Diagnostics.Debug.WriteLine("Start of the equal operation '==': ")
            } .Else {
                .Default(System.Void)
            };
            $variable = (System.Object).Block(System.Object $variable) {
                .If (.Constant<System.Reflection.RuntimePropertyInfo>(System.Object _adapter_Name) == null) { // 12 line
                    $variable = .Default(System.Object)
                } .Else {
                    .Try {
                        .Block() {
                            .If (
                                True
                            ) {
                                .Call System.Diagnostics.Debug.WriteLine("Start of the get property operation: _adapter_Name")
                            } .Else {
                                .Default(System.Void)
                            };
                            $variable = $NewScopeParameter_0._adapter_Name;
                            .If (
                                True
                            ) {
                                .Call System.Diagnostics.Debug.WriteLine("End of the get property operation: _adapter_Name")
                            } .Else {
                                .Default(System.Void)
                            };
                            .Default(System.Void)
                        }
                    } .Catch (System.Exception $var1) {
                        .Block() {
                            .Call System.Diagnostics.Debug.WriteLine("No fue posible obtener la propiedad _adapter_Name, error en la linea: 0 columna: 162 con t1.@event.Adapter.Name")
                            ;
                            .Throw .New Integra.Space.Language.Exceptions.RuntimeException(
                                "RuntimeException: Line: 0, Column: 162, Instruction: t1.@event.Adapter.Name, Error: RE5: Error with the get property operation",
                                $var1)
                        }
                    }
                };
                $variable
            } == (System.Object).Block(System.Object $variable) {
                .If (.Constant<System.Reflection.RuntimePropertyInfo>(System.Object _adapter_Name) == null) {
                    $variable = .Default(System.Object)
                } .Else {
                    .Try {
                        .Block() {
                            .If (
                                True
                            ) {
                                .Call System.Diagnostics.Debug.WriteLine("Start of the get property operation: _adapter_Name")
                            } .Else {
                                .Default(System.Void)
                            };
                            $variable = $NewScopeParameter_1._adapter_Name;
                            .If (
                                True
                            ) {
                                .Call System.Diagnostics.Debug.WriteLine("End of the get property operation: _adapter_Name")
                            } .Else {
                                .Default(System.Void)
                            };
                            .Default(System.Void)
                        }
                    } .Catch (System.Exception $var2) {
                        .Block() {
                            .Call System.Diagnostics.Debug.WriteLine("No fue posible obtener la propiedad _adapter_Name, error en la linea: 0 columna: 188 con t2.@event.Adapter.Name")
                            ;
                            .Throw .New Integra.Space.Language.Exceptions.RuntimeException(
                                "RuntimeException: Line: 0, Column: 188, Instruction: t2.@event.Adapter.Name, Error: RE5: Error with the get property operation",
                                $var2)
                        }
                    }
                };
                $variable
            };
            .If (
                True
            ) {
                .Call System.Diagnostics.Debug.WriteLine("End of the equal operation")
            } .Else {
                .Default(System.Void)
            };
            .Default(System.Void)
        }
    } .Catch (System.Exception $var3) {
        .Block() {
            .Call System.Diagnostics.Debug.WriteLine("Error con la expresion de igualdad en la linea: 0 columna: 167 con t1.@event.Adapter.Name == t2.@event.Adapter.Name")
            ;
            .Throw .New Integra.Space.Language.Exceptions.RuntimeException(
                "RuntimeException: Line: 0, Column: 167, Instruction: t1.@event.Adapter.Name == t2.@event.Adapter.Name, Error: RE43: Error with the equal operation '=='",
                $var3)
        }
    };
    $variable
}

我怀疑是内核的这一行抛出了错误

BoundConstants line 133

顺便说一句：C# 中的 非平凡值 是什么？我该如何解决这个问题？

如果您需要更多信息，请告诉我

Answer 1

我解决了这个问题，如果您想使用 CompileToMethod 方法将表达式转换为方法的 IL 主体，基本上您不能将反射用于表达式树.现在这是我的 onCondition 调试视图：

.Block(System.Boolean $variable) {
    .Try {
        .Block() {
            .If (
                True
            ) {
                .Call System.Diagnostics.Debug.WriteLine("Start of the equal operation '==': ")
            } .Else {
                .Default(System.Void)
            };
            $variable = (System.Object).Block(System.Object $variable) {
                .If (True == False) { // 12 line
                    $variable = .Default(System.Object)
                } .Else {
                    .Try {
                        .Block() {
                            .If (
                                True
                            ) {
                                .Call System.Diagnostics.Debug.WriteLine("Start of the get property operation: _adapter_Name")
                            } .Else {
                                .Default(System.Void)
                            };
                            $variable = $NewScopeParameter_0._adapter_Name;
                            .If (
                                True
                            ) {
                                .Call System.Diagnostics.Debug.WriteLine("End of the get property operation: _adapter_Name")
                            } .Else {
                                .Default(System.Void)
                            };
                            .Default(System.Void)
                        }
                    } .Catch (System.Exception $var1) {
                        .Block() {
                            .Call System.Diagnostics.Debug.WriteLine("No fue posible obtener la propiedad _adapter_Name, error en la linea: 0 columna: 162 con t1.@event.Adapter.Name")
                            ;
                            .Throw .New Integra.Space.Language.Exceptions.RuntimeException(
                                "RuntimeException: Line: 0, Column: 162, Instruction: t1.@event.Adapter.Name, Error: RE5: Error with the get property operation",
                                $var1)
                        }
                    }
                };
                $variable
            } == (System.Object).Block(System.Object $variable) {
                .If (True == False) {
                    $variable = .Default(System.Object)
                } .Else {
                    .Try {
                        .Block() {
                            .If (
                                True
                            ) {
                                .Call System.Diagnostics.Debug.WriteLine("Start of the get property operation: _adapter_Name")
                            } .Else {
                                .Default(System.Void)
                            };
                            $variable = $NewScopeParameter_1._adapter_Name;
                            .If (
                                True
                            ) {
                                .Call System.Diagnostics.Debug.WriteLine("End of the get property operation: _adapter_Name")
                            } .Else {
                                .Default(System.Void)
                            };
                            .Default(System.Void)
                        }
                    } .Catch (System.Exception $var2) {
                        .Block() {
                            .Call System.Diagnostics.Debug.WriteLine("No fue posible obtener la propiedad _adapter_Name, error en la linea: 0 columna: 188 con t2.@event.Adapter.Name")
                            ;
                            .Throw .New Integra.Space.Language.Exceptions.RuntimeException(
                                "RuntimeException: Line: 0, Column: 188, Instruction: t2.@event.Adapter.Name, Error: RE5: Error with the get property operation",
                                $var2)
                        }
                    }
                };
                $variable
            };
            .If (
                True
            ) {
                .Call System.Diagnostics.Debug.WriteLine("End of the equal operation")
            } .Else {
                .Default(System.Void)
            };
            .Default(System.Void)
        }
    } .Catch (System.Exception $var3) {
        .Block() {
            .Call System.Diagnostics.Debug.WriteLine("Error con la expresion de igualdad en la linea: 0 columna: 167 con t1.@event.Adapter.Name == t2.@event.Adapter.Name")
            ;
            .Throw .New Integra.Space.Language.Exceptions.RuntimeException(
                "RuntimeException: Line: 0, Column: 167, Instruction: t1.@event.Adapter.Name == t2.@event.Adapter.Name, Error: RE43: Error with the equal operation '=='",
                $var3)
        }
    };
    $variable
}

你可以看到第 12 行我删除了反射的使用以获得属性 _adapter_Name.

Answer 2

What is non-trivial value in C#? How could I fix this?*

一般null, bool, char, sbyte, byte, short, ushort, int, uint, long, ulong, float, double, decimal, string, Type, MethodBase 都可以。其他都不是。

从VariableBinder.VisitConstant开始就可以看到：

if (ILGen.CanEmitConstant(node.Value, node.Type))
{
    return node;
}
this._constants.Peek().AddReference(node.Value, node.Type);

转到 AddReference 是不好的，并且会在长时间运行中导致您看到的异常。

然后您可以查看 ILGen.CanEmitConstant 并查看已完成的测试。

为什么会这样？因为你正试图在一个方法中编译一个对象。虽然如果您使用 LambdaExpression.Compile() 这通常是可能的，因为对象并没有真正保存在方法中，而只是对内存中对象的引用，如果您使用 CompileToMethod() . NET 必须能够在方法内保存对象的副本，因为 CompileToMethod()（和 MethodBuilder/TypeBuilder/AssemblyBuilder）能够生成新的 dll。这些 dll 可以在 machines/loaded 天后与其他 machines/loaded 共享（它们是 "normal" dll），因此不能保证它们仅在当前程序的生命周期内是运行。为此，.NET 需要序列化对象，然后在调用方法时反序列化它。但这不受支持。显然，这不会发生在某些原始类型（我会注意到并非所有 .NET 原始类型都受支持。缺少 IntPtr 和 UIntPtr）以及一些特殊类型，如 Type（在 .NET 中有特殊处理）。

CompileToMethod 无法编译常量“<some value>”，因为它是一个非常重要的值，例如活动对象

CompileToMethod cannot compile constant '<some value>' because it is a non-trivial value, such as a live object

c#

linq

expression

cil

expression-trees