diff options
Diffstat (limited to 'src/glsl/lower_buffer_access.cpp')
| -rw-r--r-- | src/glsl/lower_buffer_access.cpp | 177 |
1 files changed, 177 insertions, 0 deletions
diff --git a/src/glsl/lower_buffer_access.cpp b/src/glsl/lower_buffer_access.cpp index 0f5ba17bbf9..7e9d516d74a 100644 --- a/src/glsl/lower_buffer_access.cpp +++ b/src/glsl/lower_buffer_access.cpp @@ -303,4 +303,181 @@ lower_buffer_access::is_dereferenced_thing_row_major(const ir_rvalue *deref) return false; } +/** + * This function initializes various values that will be used later by + * emit_access when actually emitting loads or stores. + * + * Note: const_offset is an input as well as an output, clients must + * initialize it to the offset of the variable in the underlying block, and + * this function will adjust it by adding the constant offset of the member + * being accessed into that variable. + */ +void +lower_buffer_access::setup_buffer_access(void *mem_ctx, + ir_variable *var, + ir_rvalue *deref, + ir_rvalue **offset, + unsigned *const_offset, + bool *row_major, + int *matrix_columns, + unsigned packing) +{ + *offset = new(mem_ctx) ir_constant(0u); + *row_major = is_dereferenced_thing_row_major(deref); + *matrix_columns = 1; + + /* Calculate the offset to the start of the region of the UBO + * dereferenced by *rvalue. This may be a variable offset if an + * array dereference has a variable index. + */ + while (deref) { + switch (deref->ir_type) { + case ir_type_dereference_variable: { + deref = NULL; + break; + } + + case ir_type_dereference_array: { + ir_dereference_array *deref_array = (ir_dereference_array *) deref; + unsigned array_stride; + if (deref_array->array->type->is_vector()) { + /* We get this when storing or loading a component out of a vector + * with a non-constant index. This happens for v[i] = f where v is + * a vector (or m[i][j] = f where m is a matrix). If we don't + * lower that here, it gets turned into v = vector_insert(v, i, + * f), which loads the entire vector, modifies one component and + * then write the entire thing back. That breaks if another + * thread or SIMD channel is modifying the same vector. + */ + array_stride = 4; + if (deref_array->array->type->is_double()) + array_stride *= 2; + } else if (deref_array->array->type->is_matrix() && *row_major) { + /* When loading a vector out of a row major matrix, the + * step between the columns (vectors) is the size of a + * float, while the step between the rows (elements of a + * vector) is handled below in emit_ubo_loads. + */ + array_stride = 4; + if (deref_array->array->type->is_double()) + array_stride *= 2; + *matrix_columns = deref_array->array->type->matrix_columns; + } else if (deref_array->type->without_array()->is_interface()) { + /* We're processing an array dereference of an interface instance + * array. The thing being dereferenced *must* be a variable + * dereference because interfaces cannot be embedded in other + * types. In terms of calculating the offsets for the lowering + * pass, we don't care about the array index. All elements of an + * interface instance array will have the same offsets relative to + * the base of the block that backs them. + */ + deref = deref_array->array->as_dereference(); + break; + } else { + /* Whether or not the field is row-major (because it might be a + * bvec2 or something) does not affect the array itself. We need + * to know whether an array element in its entirety is row-major. + */ + const bool array_row_major = + is_dereferenced_thing_row_major(deref_array); + + /* The array type will give the correct interface packing + * information + */ + if (packing == GLSL_INTERFACE_PACKING_STD430) { + array_stride = deref_array->type->std430_array_stride(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; + if (array_index->type->base_type == GLSL_TYPE_INT) + array_index = i2u(array_index); + + ir_constant *const_index = + array_index->constant_expression_value(NULL); + if (const_index) { + *const_offset += array_stride * const_index->value.u[0]; + } else { + *offset = add(*offset, + mul(array_index, + new(mem_ctx) ir_constant(array_stride))); + } + deref = deref_array->array->as_dereference(); + break; + } + + case ir_type_dereference_record: { + ir_dereference_record *deref_record = (ir_dereference_record *) deref; + const glsl_type *struct_type = deref_record->record->type; + unsigned intra_struct_offset = 0; + + for (unsigned int i = 0; i < struct_type->length; i++) { + const glsl_type *type = struct_type->fields.structure[i].type; + + ir_dereference_record *field_deref = new(mem_ctx) + ir_dereference_record(deref_record->record, + struct_type->fields.structure[i].name); + const bool field_row_major = + is_dereferenced_thing_row_major(field_deref); + + ralloc_free(field_deref); + + unsigned field_align = 0; + + if (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); + + if (strcmp(struct_type->fields.structure[i].name, + deref_record->field) == 0) + break; + + if (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: + * + * "The structure may have padding at the end; the base offset + * of the member following the sub-structure is rounded up to + * the next multiple of the base alignment of the structure." + */ + if (type->without_array()->is_record()) { + intra_struct_offset = glsl_align(intra_struct_offset, + field_align); + + } + } + + *const_offset += intra_struct_offset; + deref = deref_record->record->as_dereference(); + break; + } + + case ir_type_swizzle: { + ir_swizzle *deref_swizzle = (ir_swizzle *) deref; + + assert(deref_swizzle->mask.num_components == 1); + + *const_offset += deref_swizzle->mask.x * sizeof(int); + deref = deref_swizzle->val->as_dereference(); + break; + } + + default: + assert(!"not reached"); + deref = NULL; + break; + } + } +} + } /* namespace lower_buffer_access */ |