[Mesa-dev] [PATCH] glsl: Avoid calling get_array_element for scalar constants

[Danylo Piliaiev]

Hi,


On 08/14/2018 10:53 AM, Tapani Pälli wrote:
> Hi;
>
> On 08/13/2018 06:57 PM, Danylo Piliaiev wrote:
>> Accessing scalar constant as an array in function call or
>> initializer list triggered assert in get_array_element.
>> Examples:
>>     func(0[0]);
>>     vec2 t = { 0[0], 0 };
>>
>> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=107550
>>
>> Signed-off-by: Danylo Piliaiev <danylo.piliaiev at globallogic.com>
>> ---
>>   src/compiler/glsl/ir_constant_expression.cpp | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/src/compiler/glsl/ir_constant_expression.cpp 
>> b/src/compiler/glsl/ir_constant_expression.cpp
>> index 4a0aff72c6..c9788c7053 100644
>> --- a/src/compiler/glsl/ir_constant_expression.cpp
>> +++ b/src/compiler/glsl/ir_constant_expression.cpp
>> @@ -826,7 +826,7 @@ 
>> ir_dereference_array::constant_expression_value(void *mem_ctx,
>>            const unsigned component = idx->value.u[0];
>>              return new(mem_ctx) ir_constant(array, component);
>> -      } else {
>> +      } else if (array->type->is_array()) {
>
> IMO this is correct but we could alternatively bail out already 
> earlier before the topmost if-statement or just add this condition as 
> part of the topmost if-statement?
>
We don't have "accessible_as_array" kind of check (correct me if I'm 
wrong), vector and matrix are not is_array so to bail out earlier there 
should be a check:
is_matrix || is_vector || is_array
or add new method to glsl_type. But from my perspective this will only 
invert conditions order in constant_expression_value.
>>            const unsigned index = idx->value.u[0];
>>            return array->get_array_element(index)->clone(mem_ctx, NULL);
>>         }
>>
>
> // Tapani