InstructionEncoder Struct-datatyp

Definition

public value class InstructionEncoder

public readonly struct InstructionEncoder

public struct InstructionEncoder

type InstructionEncoder = struct

Public Structure InstructionEncoder

Arv

Object

ValueType

InstructionEncoder

Exempel

Det här exemplet visar hur du genererar en metodtext med hjälp av InstructionEncoder:

// The following code emits a method body similar to this C# code:

/*public static double CalcRectangleArea(double length, double width)
{
    if (length < 0.0)
    {
        throw new ArgumentOutOfRangeException("length");
    }

    if (width < 0.0)
    {
        throw new ArgumentOutOfRangeException("width");
    }

    return length * width;
}*/

private static InstructionEncoder EmitMethodBody(MetadataBuilder metadata, AssemblyReferenceHandle corlibAssemblyRef)
{
    var codeBuilder = new BlobBuilder();
    var encoder = new InstructionEncoder(codeBuilder, new ControlFlowBuilder());

    // Get a reference to the System.ArgumentOutOfRangeException type
    TypeReferenceHandle typeRefHandle = metadata.AddTypeReference(
    corlibAssemblyRef,
    metadata.GetOrAddString("System"),
    metadata.GetOrAddString("ArgumentOutOfRangeException"));

    // Signature: .ctor(string)
    var ctorSignature = new BlobBuilder();

    new BlobEncoder(ctorSignature).
        MethodSignature(isInstanceMethod: true).
        Parameters(1, returnType => returnType.Void(), parameters => parameters.AddParameter().Type().String());

    BlobHandle ctorBlobIndex = metadata.GetOrAddBlob(ctorSignature);

    // Get a reference to the System.ArgumentOutOfRangeException constructor
    MemberReferenceHandle ctorMemberRef = metadata.AddMemberReference(
        typeRefHandle,
        metadata.GetOrAddString(".ctor"),
        ctorBlobIndex);

    LabelHandle label1 = encoder.DefineLabel();
    LabelHandle label2 = encoder.DefineLabel();

    // ldarg.0
    encoder.OpCode(ILOpCode.Ldarg_0);

    // ldc.r8 0
    encoder.LoadConstantR8(0);

    // bge.un.s LABEL1
    encoder.Branch(ILOpCode.Bge_un_s, label1);

    // ldstr "length"
    encoder.LoadString(metadata.GetOrAddUserString("length"));

    // newobj instance void [System.Runtime]System.ArgumentOutOfRangeException::.ctor(string)
    encoder.OpCode(ILOpCode.Newobj);
    encoder.Token(ctorMemberRef);

    // throw
    encoder.OpCode(ILOpCode.Throw);

    // LABEL1: ldarg.1
    encoder.MarkLabel(label1);
    encoder.OpCode(ILOpCode.Ldarg_1);

    // ldc.r8 0
    encoder.LoadConstantR8(0);

    // bge.un.s LABEL2
    encoder.Branch(ILOpCode.Bge_un_s, label2);

    // ldstr "width"
    encoder.LoadString(metadata.GetOrAddUserString("width"));

    // newobj instance void [System.Runtime]System.ArgumentOutOfRangeException::.ctor(string)
    encoder.OpCode(ILOpCode.Newobj);
    encoder.Token(ctorMemberRef);

    // throw
    encoder.OpCode(ILOpCode.Throw);

    // LABEL2: ldarg.0
    encoder.MarkLabel(label2);
    encoder.OpCode(ILOpCode.Ldarg_0);

    // ldarg.1
    encoder.OpCode(ILOpCode.Ldarg_1);

    // mul
    encoder.OpCode(ILOpCode.Mul);

    // ret
    encoder.OpCode(ILOpCode.Ret);

    return encoder;
}

Kommentarer

Klassen InstructionEncoder används för att generera CIL-instruktioner som utgör en metodtext. Ett fullständigt exempel på hur du genererar en metod finns i klassdokumentationen MetadataBuilder .