动态类型创建中的MethodBuilder.CreateMethodBody()问题 [英] MethodBuilder.CreateMethodBody() problem in Dynamic Type creation
问题描述
对于一个实验，我试图从源类型读取方法主体(使用 GetILAsByteArray())并将其添加到新的类型中(使用 CreateMethodBody() ).
我的源类就是这个
public class FullClass
{
public string Test(string data)
{
return data;
}
public string Test2(string data)
{
return data;
}
public string Test5(string data, string data1)
{
return data + data1;
}
}
为此代码生成的IL(使用反射器获取)
.method public hidebysig instance string Test(string data) cil managed
{
.maxstack 1
.locals init (
[0] string CS$1$0000)
L_0000: nop
L_0001: ldarg.1
L_0002: stloc.0
L_0003: br.s L_0005
L_0005: ldloc.0
L_0006: ret
}
但是从我的新类型生成的IL看起来像这样
.method public hidebysig virtual instance string Test(string) cil managed
{
.maxstack 0
L_0000: nop
L_0001: ldarg.1
L_0002: stloc.0
L_0003: br.s L_0005
L_0005: ldloc.0
L_0006: ret
}
差异是maxstack值& .locals指令.我不明白为什么我的实际班级会生成本地语言，尽管它没有任何本地变量?
为什么在.maxstack值上存在差异，因为从源使用了相同的IL来创建新的Type ??
由于这种情况，在调用方法时出现错误公共语言运行库检测到无效程序" .
我创建动态类型的代码如下
public static class Mixin<Target>
{
public static Target compose<TSource>()
{
Type newType = null;
AppDomain currentDom = Thread.GetDomain();
AssemblyName DAssembly = new AssemblyName();
DAssembly.Name = "DynamicTypesAssembly";
AssemblyBuilder DAssemblyBldr = currentDom.DefineDynamicAssembly(
DAssembly,
AssemblyBuilderAccess.RunAndSave);
ModuleBuilder DModuleBldr = DAssemblyBldr.DefineDynamicModule(DAssembly.Name, DAssembly.Name + ".dll", false);
// var DInterface = EmitInterface(DModuleBldr);
TypeBuilder TypeBldr = DModuleBldr.DefineType("WorkOut.DType",
TypeAttributes.Public | TypeAttributes.BeforeFieldInit | TypeAttributes.Serializable
,typeof(object), new[] { typeof(Target) });
//TypeBldr.AddInterfaceImplementation(typeof(DInterface));
var methodCol = typeof(Target).GetMethods(BindingFlags.Public| BindingFlags.Instance);
foreach (var ms in methodCol)
{
var paramCol = ms.GetParameters();
var paramTypeArray = paramCol.Select(x => x.ParameterType).ToArray();
var paramNameArray = paramCol.Select(x=>x.Name).ToArray();
MethodBuilder MthdBldr = TypeBldr.DefineMethod(ms.Name,
MethodAttributes.Public | MethodAttributes.Virtual | MethodAttributes.HideBySig,
ms.ReturnType,
paramTypeArray);
for(int i=0;i<paramCol.Count();i++)
{
MthdBldr.DefineParameter(i+1, ParameterAttributes.None, paramNameArray[i]);
}
MethodInfo[] methodInfos = typeof(TSource).GetMethods(BindingFlags.Public | BindingFlags.NonPublic |
BindingFlags.Static | BindingFlags.Instance);
for (int i = 0; i < methodInfos.Count(); i++)
{
var paramSrc = methodInfos[i].GetParameters();
var paramSrcTypeArray = paramSrc.Select(x => x.ParameterType).ToArray();
if (methodInfos[i].Name == ms.Name && methodInfos[i].ReturnType == ms.ReturnType && paramSrc.Count() == paramCol.Count() && paramTypeArray.SequenceEqual(paramSrcTypeArray))
{
var ILcodes = methodInfos[i].GetMethodBody().GetILAsByteArray();
var ilGen = MthdBldr.GetILGenerator();
//ilGen.Emit(OpCodes.Ldarg_0); //Load the 'this' reference onto the evaluation stack
//ilGen.Emit(OpCodes.Initobj);
MthdBldr.CreateMethodBody(ILcodes, ILcodes.Length);
//ilGen.Emit(OpCodes.Ret);
break;
}
}
}
newType = TypeBldr.CreateType();
DAssemblyBldr.Save("a.dll");
return (Target)Activator.CreateInstance(newType);
}
调用此代码是
var resMix = Mixin<ITest>.compose<FullClass>();
var returned1 = resMix.Test("sam");
并且ITest(目标)界面是
public interface ITest
{
string Test(string data);
}
在评论此行时
//var ilGen = MthdBldr.GetILGenerator();
maxstack变为 .maxstack 16
我针对 PEverify 工具针对新的dll运行了检查，这给出了以下错误
WorkOut.DType :: Test] [偏移量0x00000002]无法识别的局部变量号.
任何帮助都非常感激....:)
作为有关 while calling the method.
My code creating the Dynamic type looks like this
public static class Mixin<Target>
{
public static Target compose<TSource>()
{
Type newType = null;
AppDomain currentDom = Thread.GetDomain();
AssemblyName DAssembly = new AssemblyName();
DAssembly.Name = "DynamicTypesAssembly";
AssemblyBuilder DAssemblyBldr = currentDom.DefineDynamicAssembly(
DAssembly,
AssemblyBuilderAccess.RunAndSave);
ModuleBuilder DModuleBldr = DAssemblyBldr.DefineDynamicModule(DAssembly.Name, DAssembly.Name + ".dll", false);
// var DInterface = EmitInterface(DModuleBldr);
TypeBuilder TypeBldr = DModuleBldr.DefineType("WorkOut.DType",
TypeAttributes.Public | TypeAttributes.BeforeFieldInit | TypeAttributes.Serializable
,typeof(object), new[] { typeof(Target) });
//TypeBldr.AddInterfaceImplementation(typeof(DInterface));
var methodCol = typeof(Target).GetMethods(BindingFlags.Public| BindingFlags.Instance);
foreach (var ms in methodCol)
{
var paramCol = ms.GetParameters();
var paramTypeArray = paramCol.Select(x => x.ParameterType).ToArray();
var paramNameArray = paramCol.Select(x=>x.Name).ToArray();
MethodBuilder MthdBldr = TypeBldr.DefineMethod(ms.Name,
MethodAttributes.Public | MethodAttributes.Virtual | MethodAttributes.HideBySig,
ms.ReturnType,
paramTypeArray);
for(int i=0;i<paramCol.Count();i++)
{
MthdBldr.DefineParameter(i+1, ParameterAttributes.None, paramNameArray[i]);
}
MethodInfo[] methodInfos = typeof(TSource).GetMethods(BindingFlags.Public | BindingFlags.NonPublic |
BindingFlags.Static | BindingFlags.Instance);
for (int i = 0; i < methodInfos.Count(); i++)
{
var paramSrc = methodInfos[i].GetParameters();
var paramSrcTypeArray = paramSrc.Select(x => x.ParameterType).ToArray();
if (methodInfos[i].Name == ms.Name && methodInfos[i].ReturnType == ms.ReturnType && paramSrc.Count() == paramCol.Count() && paramTypeArray.SequenceEqual(paramSrcTypeArray))
{
var ILcodes = methodInfos[i].GetMethodBody().GetILAsByteArray();
var ilGen = MthdBldr.GetILGenerator();
//ilGen.Emit(OpCodes.Ldarg_0); //Load the 'this' reference onto the evaluation stack
//ilGen.Emit(OpCodes.Initobj);
MthdBldr.CreateMethodBody(ILcodes, ILcodes.Length);
//ilGen.Emit(OpCodes.Ret);
break;
}
}
}
newType = TypeBldr.CreateType();
DAssemblyBldr.Save("a.dll");
return (Target)Activator.CreateInstance(newType);
}
And code for invoking this is
var resMix = Mixin<ITest>.compose<FullClass>();
var returned1 = resMix.Test("sam");
Edit: And the ITest (Target) interface is
public interface ITest
{
string Test(string data);
}
EDIT:
when commenting this line
//var ilGen = MthdBldr.GetILGenerator();
maxstack becomes .maxstack 16
I ran a check against the new dll against PEverify tool, this gives following error
WorkOut.DType::Test][offset 0x00000002] Unrecognized local variable number.
Any help really appreciated.... :)
As the MSDN page about CreateMethodBody says, this is not fully supported.
It's very probable that the implementation doesn't parse the IL a byte array, so it sets a maxstack to 16 out of the blue.
If you create an ILGenerator for the method, it will set the method maxstack to zero. The ILGenerator will increment it when you'll use the different Emit overloads. As you're not doing so, and use CreateMethodBody, it stays zeroed. This explains the difference.
CreateMethodBody is definitely problematic for scenarios which involves anything but simple code. Every opcode which takes a metadata token won't be usable, as you don't know the finite token in the scope of the module when you create a byte array. And it doesn't allow you to emit exception handlers.
Long story short, CreateMethodBody as it is, is pointless.
If you want to continue the experimentation, I suggest you use my reflection IL reader to get a representation of the Instruction of the methods, then use an ILGenerator to reproduce the method body inside a method builder.
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