Re: [PATCH 2/3] Allocate data in cached_reg_t

[Luis Machado <lgustavo@codesourcery.com>]

On 01/10/2017 06:59 AM, Yao Qi wrote:
> On 17-01-09 14:11:13, Luis Machado wrote:
>>> @@ -6306,7 +6306,7 @@ remote_console_output (char *msg)
>>> typedef struct cached_reg
>>> {
>>>   int num;
>>> -  gdb_byte data[MAX_REGISTER_SIZE];
>>> +  gdb_byte *data;
>>
>> Would it make sense to go C++ and use a data structure that can take
>> care of variable sizes? Just thinking if that would be easier than
>> handling allocation/deallocation of the data.
>>
>
> Do you suggest std::vector?  We still need to allocate/deallocate it
> if we change "gdb_byte *data" to "std::vector<gdb_byte> *data", or we
> have to convert cached_reg to class, and do RAII.
>

Something like std::vector, yes. But it is true we will still need to 
allocate the vector itself.

I was pondering about the benefits of not being limited to a specific 
register size. Then we wouldn't need to worry about adjusting things as 
we have to do now.

As i see it, data[register_size(register_size (gdbarch, num)] wouldn't 
be much different than data[MAX_REGISTER_SIZE]. The only thing is that 
we're setting the max register size dynamically.

We may or may not need this flexibility right now, but who knows what 
weird architectures we may have in the future.