Re: [patch, libgomp, OpenACC] Additional enter/exit data map handling

[Chung-Lin Tang <chunglin_tang at mentor dot com>]

On 2016/9/6 8:11 PM, Thomas Schwinge wrote:
> Hi!
> 
> On Mon, 29 Aug 2016 15:46:47 +0800, Chung-Lin Tang <cltang@codesourcery.com> wrote:
>> this patch is a port of some changes from gomp-4_0-branch,
>> including adding additional map type handling in OpenACC enter/exit data
>> directives, and some pointer set handling changes. Updated
>> testsuite case are also included.
>>
>> Tested on trunk to ensure no regressions, is this okay for trunk?
> 
>> 2016-08-29  Cesar Philippidis  <cesar@codesourcery.com>
>>             Thomas Schwinge  <thomas@codesourcery.com>
>>             Chung-Lin Tang  <cltang@codesourcery.com>
> 
> Maybe I'm misremembering, but I can't remember having been involved in
> this.  ;-)

A part of this was picked from r223178, which you committed to gomp-4_0-branch.

>> +/* Returns the number of mappings associated with the pointer or pset. PSET
>> +   have three mappings, whereas pointer have two.  */
>> +
>>  static int
>> -find_pset (int pos, size_t mapnum, unsigned short *kinds)
>> +find_pointer (int pos, size_t mapnum, unsigned short *kinds)
>>  {
>>    if (pos + 1 >= mapnum)
>>      return 0;
>>  
>>    unsigned char kind = kinds[pos+1] & 0xff;
>>  
>> -  return kind == GOMP_MAP_TO_PSET;
>> +  if (kind == GOMP_MAP_TO_PSET)
>> +    return 3;
>> +  else if (kind == GOMP_MAP_POINTER)
>> +    return 2;
>> +
>> +  return 0;
>>  }
> 
> I'm still confused about that find_pset/find_pointer handling.  Why is
> that required?  Essentially, that means that GOACC_enter_exit_data is
> skipping over some mappings, right?  If yes, why do the front ends
> (Fortran only?) then emit these mappings to begin with, if we're then
> ignoring them in the runtime?

It's not skipping mappings. GOMP_MAP_PSET uses 3 continuous entries while
GOMP_MAP_POINTER uses 2, see how these are eventually processed together
in gomp_map_vars().

Chung-Lin