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akeit0

•Created by akeit0 on 2/15/2025 in #help

How to get the direct function pointer of virtual struct method?

How to Get the Function Pointer of FooStruct.Foo? I have the following C# code:

interface IFoo
{
    void Foo();
}

struct FooStruct : IFoo
{
    public void Foo() { }
}

interface IFoo
{
    void Foo();
}

struct FooStruct : IFoo
{
    public void Foo() { }
}

To obtain the function pointer of FooStruct.Foo, I used:

var fp = typeof(FooStruct).GetMethod("Foo").MethodHandle.GetFunctionPointer();

var fp = typeof(FooStruct).GetMethod("Foo").MethodHandle.GetFunctionPointer();

However, fp does not point to the actual method implementation I need. Instead, it refers to the function pointer for the boxed version of FooStruct. For reference, the generated assembly is this:

L0000: add rcx, 8
L0004: mov rax, TargetFunctionPointer
L000e: jmp rax

L0000: add rcx, 8
L0004: mov rax, TargetFunctionPointer
L000e: jmp rax

I can retrieve TargetFunctionPointer by analyzing the JIT-compiled native code, but I’m looking for a more direct or reliable approach. Is there a better way to get the actual function pointer of FooStruct.Foo?

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