struct tree_type

[Manuel López-Ibáñez]

On 13 July 2010 11:09, Ian Lance Taylor <iant@google.com> wrote:
> BLUE 3TOO <blue_3too@hotmail.com> writes:
>
>>      Can somebody quickly explain what the bit fields are for? thanks
>>
>>   unsigned int precision : 10;
>>   unsigned no_force_blk_flag : 1;
>>   unsigned needs_constructing_flag : 1;
>>   unsigned transparent_aggr_flag : 1;
>>   unsigned restrict_flag : 1;
>>   unsigned contains_placeholder_bits : 2;
>>   ENUM_BITFIELD(machine_mode) mode : 8;
>>   unsigned string_flag : 1;
>>   unsigned lang_flag_0 : 1;
>>   unsigned lang_flag_1 : 1;
>>   unsigned lang_flag_2 : 1;
>>   unsigned lang_flag_3 : 1;
>>   unsigned lang_flag_4 : 1;
>>   unsigned lang_flag_5 : 1;
>>   unsigned lang_flag_6 : 1;
>
> Look for the uses of the bitfields in the macros in tree.h, and look at
> the comments on those macros.  Never refer to the fields directly;
> always use the macros.
>
> E.g., no_force_blk_flag is used in two macros, TYPE_NO_FORCE_BLK and
> TYPE_IS_SIZETYPE, and the comments explain when those macros are valid
> and what they mean.
>
> The lang_flag_N fields are used for frontend specific purposes, so for
> them you have to look at the individual frontends.

Blue_3too, an improvement would be to submit a patch adding the above
explanation as comments before the bitfields (where you would have
expected to find such explanation). Such a small patch does not
require copyright assignment, just send it to gcc-patches with a
changelog.

Cheers,

Manuel.