Re: [RFC 2/3] Record function descriptor address instead of function address in value

[Simon Marchi <simon.marchi@polymtl.ca>]

On 2016-10-14 06:53, Yao Qi wrote:
> In this patch, I add a new gdbarch method convert_from_func_addr, which
> converts function address back to function descriptor address or
> function pointer address.  It is the reversed operation of
> convert_from_func_ptr_addr.  We convert function address to function
> descriptor address when,

I think these could be better named, byt saying what it converts from 
_and_ what it converts to.  With convert_from_func_addr, we know it 
takes as input a function address, but we don't know what it converts it 
to.  What about something like convert_func_address_to_descriptor (or 
convert_func_addr_to_desc if you prefer shorter names)?

I think that it would also be clearer if we always used the same 
terminology (address and descriptor seem good).  It is not very 
intuitive what is the difference between convert_from_func_ptr_addr and 
convert_from_func_addr.  "function pointer address" and "function 
address" sound too close to each other, so it's easy to confuse them...

> 3. User visible changes
> 
> This patch brings several user visible changes, which look more
> accurate, shown by this table below,
> 
>  COMMAND           BEFORE                       AFTER
>  p main            main function address        main function 
> descriptor
>                                                 address
>  disass main       disassembly function main    not changed
>  disass main+4,+4  disassembly 4 bytes from     disassembly 4 bytes 
> from
>                    function main address + 4    main's function 
> descriptor + 4
>  x/i main          show one instruction on      show one instruction on 
> main's
>                    function main address        function descriptor
> 
> Although the latter looks inconvenient, that is consistent to the
> meaning on C language level.  Due to these changes, test cases are
> adjusted accordingly.

Could you provide example of the actual output of those commands, before 
and after?  It is not clear to me what the difference will be.

Thanks,

Simon