[Mesa-dev] [PATCHv2 04/13] glsl: protect anonymous struct id with a mutex

[Chia-I Wu]

On Thu, Aug 14, 2014 at 3:03 AM, Ian Romanick <idr at freedesktop.org> wrote:
> On 07/09/2014 12:47 AM, Chia-I Wu wrote:
>> There may be two contexts compiling shaders at the same time, and we want the
>> anonymous struct id to be globally unique.
>>
>> Signed-off-by: Chia-I Wu <olv at lunarg.com>
>> ---
>>  src/glsl/glsl_parser_extras.cpp | 10 ++++++++--
>>  1 file changed, 8 insertions(+), 2 deletions(-)
>>
>> diff --git a/src/glsl/glsl_parser_extras.cpp b/src/glsl/glsl_parser_extras.cpp
>> index b327c2b..ad31469 100644
>> --- a/src/glsl/glsl_parser_extras.cpp
>> +++ b/src/glsl/glsl_parser_extras.cpp
>> @@ -1347,9 +1347,15 @@ ast_struct_specifier::ast_struct_specifier(const char *identifier,
>>                                          ast_declarator_list *declarator_list)
>>  {
>>     if (identifier == NULL) {
>> +      static mtx_t mutex = _MTX_INITIALIZER_NP;
>>        static unsigned anon_count = 1;
>> -      identifier = ralloc_asprintf(this, "#anon_struct_%04x", anon_count);
>> -      anon_count++;
>> +      unsigned count;
>> +
>> +      mtx_lock(&mutex);
>> +      count = anon_count++;
>> +      mtx_unlock(&mutex);
>
> My previous feedback on this was to try and use some sort of atomic
> counter when available.  I'm not excited about the performance hit of
> taking a lock here.  Although, this probably isn't hit too much.  After
> this lands, can you submit an enhancement bug for this issue?
Sure.  I responded to that feedback without getting any ACK or NACK.
>
>> +
>> +      identifier = ralloc_asprintf(this, "#anon_struct_%04x", count);
>>     }
>>     name = identifier;
>>     this->declarations.push_degenerate_list_at_head(&declarator_list->link);
>>
>



-- 
olv at LunarG.com