Measuring argument offset in gRPC classes

[Youssef Esseddiq]

Hi,

As a simple example of my problem, I'm trying to measure the offset of the argument 'send_initial_metadata' in the 'grpc_chttp2_stream' class. This has been done for older versions of gRPC < v1.41.1 but as you know the grpc codebase keeps changing and the offset calculation needs to be redone for most of the newer versions. 

 

I have tried instrumenting the grpc codebase using things like 'offset_of' from 'stddef.h' but I did not get accurate offsets. For example, the offset of the argument 'send_initial_metadata' in the 'grpc_chttp2_stream' class in v1.41.1 is 0x140 from prior work. However, using 'offset_of' for the same version yields a 0x190.

Any idea of a reliable way to measure that offset? 

Thank you!