[Mesa-dev] [PATCH v4 (part2) 23/59] glsl: add std430 interface packing support to ssbo store and unsized array length

Samuel Iglesias Gonsálvez siglesias at igalia.com
Wed Sep 9 03:32:42 PDT 2015



On 08/09/15 18:52, Jordan Justen wrote:
> On 2015-08-05 01:30:20, Iago Toral Quiroga wrote:
>> From: Samuel Iglesias Gonsalvez <siglesias at igalia.com>
>>
>> Signed-off-by: Samuel Iglesias Gonsalvez <siglesias at igalia.com>
>> ---
>>  src/glsl/lower_ubo_reference.cpp | 65 ++++++++++++++++++++++++++++++----------
>>  1 file changed, 49 insertions(+), 16 deletions(-)
>>
>> diff --git a/src/glsl/lower_ubo_reference.cpp b/src/glsl/lower_ubo_reference.cpp
>> index 4f42abb..495ffcf 100644
>> --- a/src/glsl/lower_ubo_reference.cpp
>> +++ b/src/glsl/lower_ubo_reference.cpp
>> @@ -164,7 +164,7 @@ public:
>>     void emit_access(bool is_write, ir_dereference *deref,
>>                      ir_variable *base_offset, unsigned int deref_offset,
>>                      bool row_major, int matrix_columns,
>> -                    unsigned write_mask);
>> +                    bool is_std430, unsigned write_mask);
>>  
>>     ir_visitor_status visit_enter(class ir_expression *);
>>     void check_ssbo_unsized_array_length_expression(class ir_expression *);
>> @@ -343,8 +343,15 @@ lower_ubo_reference_visitor::setup_for_load_or_store(ir_variable *var,
>>              const bool array_row_major =
>>                 is_dereferenced_thing_row_major(deref_array);
>>  
>> -            array_stride = deref_array->type->std140_size(array_row_major);
>> -            array_stride = glsl_align(array_stride, 16);
>> +            /* The array type will give the correct interface packing
>> +             * information
>> +             */
>> +            if (deref_array->array->type->interface_packing == GLSL_INTERFACE_PACKING_STD430) {
>> +               array_stride = deref_array->type->std430_size(array_row_major);
>> +            } else {
>> +               array_stride = deref_array->type->std140_size(array_row_major);
>> +               array_stride = glsl_align(array_stride, 16);
>> +            }
>>           }
>>  
>>           ir_rvalue *array_index = deref_array->array_index;
>> @@ -380,7 +387,12 @@ lower_ubo_reference_visitor::setup_for_load_or_store(ir_variable *var,
>>  
>>              ralloc_free(field_deref);
>>  
>> -            unsigned field_align = type->std140_base_alignment(field_row_major);
>> +            unsigned field_align = 0;
>> +
>> +            if (struct_type->interface_packing == GLSL_INTERFACE_PACKING_STD430)
>> +               field_align = type->std430_base_alignment(field_row_major);
>> +            else
>> +               field_align = type->std140_base_alignment(field_row_major);
>>  
>>              intra_struct_offset = glsl_align(intra_struct_offset, field_align);
>>  
>> @@ -388,7 +400,10 @@ lower_ubo_reference_visitor::setup_for_load_or_store(ir_variable *var,
>>                         deref_record->field) == 0)
>>                 break;
>>  
>> -            intra_struct_offset += type->std140_size(field_row_major);
>> +            if (struct_type->interface_packing == GLSL_INTERFACE_PACKING_STD430)
>> +               intra_struct_offset += type->std430_size(field_row_major);
>> +            else
>> +               intra_struct_offset += type->std140_size(field_row_major);
>>  
>>              /* If the field just examined was itself a structure, apply rule
>>               * #9:
>> @@ -463,7 +478,7 @@ lower_ubo_reference_visitor::handle_rvalue(ir_rvalue **rvalue)
>>  
>>     deref = new(mem_ctx) ir_dereference_variable(load_var);
>>     emit_access(false, deref, load_offset, const_offset,
>> -               row_major, matrix_columns, 0);
>> +               row_major, matrix_columns, false, 0);
>>     *rvalue = deref;
>>  
>>     progress = true;
>> @@ -581,6 +596,7 @@ lower_ubo_reference_visitor::emit_access(bool is_write,
>>                                           unsigned int deref_offset,
>>                                           bool row_major,
>>                                           int matrix_columns,
>> +                                         bool is_std430,
>>                                           unsigned write_mask)
>>  {
>>     if (deref->type->is_record()) {
>> @@ -599,7 +615,7 @@ lower_ubo_reference_visitor::emit_access(bool is_write,
>>  
>>           emit_access(is_write, field_deref, base_offset,
>>                       deref_offset + field_offset,
>> -                     row_major, 1,
>> +                     row_major, 1, is_std430,
>>                       writemask_for_size(field_deref->type->vector_elements));
>>  
>>           field_offset += field->type->std140_size(row_major);
>> @@ -608,7 +624,8 @@ lower_ubo_reference_visitor::emit_access(bool is_write,
>>     }
>>  
>>     if (deref->type->is_array()) {
>> -      unsigned array_stride =
>> +      unsigned array_stride = is_std430 ?
>> +         deref->type->fields.array->std430_size(row_major) :
>>           glsl_align(deref->type->fields.array->std140_size(row_major), 16);
>>  
>>        for (unsigned i = 0; i < deref->type->length; i++) {
>> @@ -618,7 +635,7 @@ lower_ubo_reference_visitor::emit_access(bool is_write,
>>                                                element);
>>           emit_access(is_write, element_deref, base_offset,
>>                       deref_offset + i * array_stride,
>> -                     row_major, 1,
>> +                     row_major, 1, is_std430,
>>                       writemask_for_size(element_deref->type->vector_elements));
>>        }
>>        return;
>> @@ -637,7 +654,7 @@ lower_ubo_reference_visitor::emit_access(bool is_write,
>>              int size_mul = deref->type->is_double() ? 8 : 4;
>>              emit_access(is_write, col_deref, base_offset,
>>                          deref_offset + i * size_mul,
>> -                        row_major, deref->type->matrix_columns,
>> +                        row_major, deref->type->matrix_columns, is_std430,
>>                          writemask_for_size(col_deref->type->vector_elements));
>>           } else {
>>              /* std140 always rounds the stride of arrays (and matrices) to a
>> @@ -646,9 +663,15 @@ lower_ubo_reference_visitor::emit_access(bool is_write,
>>               */
>>              int size_mul = (deref->type->is_double() &&
>>                              deref->type->vector_elements > 2) ? 32 : 16;
>> +            /* This is not the case for std430 matrices of two vector components */
>> +            if (is_std430 && deref->type->vector_elements <= 2) {
>> +               size_mul = deref->type->is_double() ?
>> +                           8 * deref->type->vector_elements :
>> +                           4 * deref->type->vector_elements;
>> +            }
> 
> This doesn't seem right for vector_elements == 3.
> 

This is fine for vector_elements == 3.

>From 4.30 spec, section "7.6.2.2 Standard Uniform Block Layout":

"3. If the member is a three-component vector with components consuming
N basic machine units, the base alignment is 4N."

std430 doesn't mention any change to rule 3 or to rules 5 and 7 (which
are the ones explaining matrices cases).

So, vector_elements == 3's size_mull is the same than std140 (32 or 16,
depending if it is a double type or not).

> It seems like this sort of code flow would be easier to follow:
> 
> if (is_std430) {
> } else {
> }
> 

OK.

Thanks!

Sam

> -Jordan
> 
>>              emit_access(is_write, col_deref, base_offset,
>>                          deref_offset + i * size_mul,
>> -                        row_major, deref->type->matrix_columns,
>> +                        row_major, deref->type->matrix_columns, is_std430,
>>                          writemask_for_size(col_deref->type->vector_elements));
>>           }
>>        }
>> @@ -727,6 +750,7 @@ lower_ubo_reference_visitor::write_to_memory(ir_dereference *deref,
>>     unsigned const_offset;
>>     bool row_major;
>>     int matrix_columns;
>> +   bool is_std430 = var->type->interface_packing == GLSL_INTERFACE_PACKING_STD430;
>>  
>>     /* Compute the offset to the start if the dereference as well as other
>>      * information we need to configure the write
>> @@ -747,7 +771,7 @@ lower_ubo_reference_visitor::write_to_memory(ir_dereference *deref,
>>  
>>     deref = new(mem_ctx) ir_dereference_variable(write_var);
>>     emit_access(true, deref, write_offset, const_offset,
>> -               row_major, matrix_columns, write_mask);
>> +               row_major, matrix_columns, is_std430, write_mask);
>>  }
>>  
>>  ir_visitor_status
>> @@ -864,8 +888,12 @@ lower_ubo_reference_visitor::calculate_unsized_array_stride(ir_dereference *dere
>>        const bool array_row_major =
>>           is_dereferenced_thing_row_major(deref_var);
>>  
>> -      array_stride = unsized_array_type->std140_size(array_row_major);
>> -      array_stride = glsl_align(array_stride, 16);
>> +      if (deref->type->interface_packing == GLSL_INTERFACE_PACKING_STD430) {
>> +         array_stride = unsized_array_type->std430_size(array_row_major);
>> +      } else {
>> +         array_stride = unsized_array_type->std140_size(array_row_major);
>> +         array_stride = glsl_align(array_stride, 16);
>> +      }
>>        break;
>>     }
>>     case ir_type_dereference_record:
>> @@ -880,8 +908,13 @@ lower_ubo_reference_visitor::calculate_unsized_array_stride(ir_dereference *dere
>>  
>>        const bool array_row_major =
>>           is_dereferenced_thing_row_major(deref_record);
>> -      array_stride = unsized_array_type->std140_size(array_row_major);
>> -      array_stride = glsl_align(array_stride, 16);
>> +
>> +      if (deref->type->interface_packing == GLSL_INTERFACE_PACKING_STD430) {
>> +         array_stride = unsized_array_type->std430_size(array_row_major);
>> +      } else {
>> +         array_stride = unsized_array_type->std140_size(array_row_major);
>> +         array_stride = glsl_align(array_stride, 16);
>> +      }
>>        break;
>>     }
>>     default:
>> -- 
>> 1.9.1
>>
> 


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