Re: [PATCH 4/7] Implements aarch64 process record and reverse debugging support

[Omair Javaid <omair.javaid@linaro.org>]

On 30 August 2014 08:23, Yao Qi <yao@codesourcery.com> wrote:
> Omair Javaid <omair.javaid@linaro.org> writes:
>
>> This patch defines structures, macros and functions required for process record
>> and reverse debugging support on aarch64-linux targets. Also implements
>> support for recording most if not all of instructions from a64 instruction set.
>>
>> gdb:
>>
>> 2014-06-04  Omair Javaid  <omair.javaid@linaro.org>
>>
>>       * aarch64-linux-tdep.c (aarch64_linux_init_abi): Updated.
>>       * aarch64-tdep.c (record.h): Include.
>>       (record-full.h): Include.
>>       (aarch64_record_data_proc_reg): New function.
>>       (aarch64_record_data_proc_imm): New function.
>>       (aarch64_record_branch_except_sys): New function.
>>       (aarch64_record_load_store): New function.
>>       (aarch64_record_decode_insn_handler): New function.
>>       (deallocate_reg_mem): New function.
>>       (aarch64_process_record): New function.
>>       * aarch64-tdep.h (submask): New macro.
>>       (bit): New macro.
>>       (bits): New macro.
>>       (REG_ALLOC): New macro.
>>       (MEM_ALLOC): New macro.
>>       (struct aarch64_mem_r): Defined.
>>       (aarch64_record_result): New enum.
>>       (struct insn_decode_record): Defined.
>>       (insn_decode_record): New typedef.
>>       (aarch64_process_record): New extern declaration.
>
> We want to support process record on aarch64-linux, but the code is
> added to aarch64-tdep.c.  Does aarch64-elf target need process record?
> I prefer to add code to aarch64-linux-tdep.c.  I know that code for
> process record on arm was added to arm-tdep.c too, but I don't think it
> is correct either.

If we try Record-Replay can work on any target running a gdb stub with
a little tweaking but we do need a linux host machine in all cases.
so I think *-tdep.c is the right place for it. Thats the reason
syscall recording code resides in *-linux-tdep.c but all other
instruction recording code is in *-tdep.c

>
>> diff --git a/gdb/aarch64-tdep.h b/gdb/aarch64-tdep.h
>> index 78fb779..8a193f4 100644
>> --- a/gdb/aarch64-tdep.h
>> +++ b/gdb/aarch64-tdep.h
>> @@ -90,4 +90,69 @@ struct gdbarch_tdep
>>    struct type *vnb_type;
>>  };
>>
>> +/* aarch64 process record-replay related structures, defines etc.  */
>> +
>> +#define submask(x) ((1L << ((x) + 1)) - 1)
>> +#define bit(obj,st) (((obj) >> (st)) & 1)
>> +#define bits(obj,st,fn) (((obj) >> (st)) & submask ((fn) - (st)))
>
> If they are only used in aarch64-tdep.c, please define them there.

OK

>
>> +
>> +/* ARM memory record structure.  */
>
> s/ARM/AArch64/

OK

>
>> +struct aarch64_mem_r
>> +{
>> +  uint64_t len;    /* Record length.  */
>> +  uint64_t addr;   /* Memory address.  */
>> +};
>> +
>> +enum aarch64_record_result
>> +{
>> +  AARCH64_RECORD_SUCCESS,
>> +  AARCH64_RECORD_FAILURE,
>> +  AARCH64_RECORD_USUPPORTED
>> +};
>> +
>> +/* ARM instruction record contains opcode of current insn

OK

>
> Likewise.
>
> --
> Yao (齐尧)