[Mesa-dev] [PATCH v3 (part1) 25/26] glsl: Lower shader storage buffer object writes to GLSL IR instrinsics
Samuel Iglesias Gonsálvez
siglesias at igalia.com
Sun Jul 12 22:09:25 PDT 2015
On 10/07/15 22:47, Jordan Justen wrote:
> On 2015-07-10 03:13:44, Iago Toral Quiroga wrote:
>> From: Samuel Iglesias Gonsalvez <siglesias at igalia.com>
>>
>> Extend the existing lower_ubo_reference pass to also detect SSBO writes
>> and lower them to __intrinsic_store_ssbo intrinsics.
>>
>> Signed-off-by: Samuel Iglesias Gonsalvez <siglesias at igalia.com>
>> ---
>> src/glsl/lower_ubo_reference.cpp | 441 +++++++++++++++++++++++++++------------
>> 1 file changed, 311 insertions(+), 130 deletions(-)
>>
>> diff --git a/src/glsl/lower_ubo_reference.cpp b/src/glsl/lower_ubo_reference.cpp
>> index a61ff29..460b490 100644
>> --- a/src/glsl/lower_ubo_reference.cpp
>> +++ b/src/glsl/lower_ubo_reference.cpp
>> @@ -37,6 +37,7 @@
>> #include "ir_builder.h"
>> #include "ir_rvalue_visitor.h"
>> #include "main/macros.h"
>> +#include "glsl_parser_extras.h"
>>
>> using namespace ir_builder;
>>
>> @@ -139,12 +140,31 @@ public:
>> }
>>
>> void handle_rvalue(ir_rvalue **rvalue);
>> - void emit_ubo_loads(ir_dereference *deref, ir_variable *base_offset,
>> - unsigned int deref_offset, bool row_major,
>> - int matrix_columns);
>> + ir_visitor_status visit_enter(ir_assignment *ir);
>> +
>> + void setup_for_load_or_write(ir_variable *var,
>
> How about setup_for_load_or_store, or setup_for_buffer_access?
>
I prefer the former, as it is also called for UBO reads.
>> + ir_dereference *deref,
>> + ir_rvalue **offset,
>> + unsigned *const_offset,
>> + bool *row_major,
>> + int *matrix_columns);
>> ir_expression *ubo_load(const struct glsl_type *type,
>> ir_rvalue *offset);
>>
>> +
>> + void check_for_ssbo_write(ir_assignment *ir);
>
> Since we are using load elsewhere, I guess 'store' is better than
> 'write'.
>
OK
>> + void write_to_memory(ir_dereference *deref,
>> + ir_variable *var,
>> + ir_variable *write_var,
>> + unsigned write_mask);
>> + ir_call *ssbo_write(ir_rvalue *deref, ir_rvalue *offset,
>> + unsigned write_mask);
>
> store
>
>> +
>> + void emit_reads_or_writes(bool is_write, ir_dereference *deref,
>> + ir_variable *base_offset, unsigned int deref_offset,
>> + bool row_major, int matrix_columns,
>> + unsigned write_mask);
>
> What about emit_access?
>
OK
>> +
>> void *mem_ctx;
>> struct gl_shader *shader;
>> struct gl_uniform_buffer_variable *ubo_var;
>> @@ -218,26 +238,20 @@ interface_field_name(void *mem_ctx, char *base_name, ir_dereference *d,
>> }
>>
>> void
>> -lower_ubo_reference_visitor::handle_rvalue(ir_rvalue **rvalue)
>> +lower_ubo_reference_visitor::setup_for_load_or_write(ir_variable *var,
>> + ir_dereference *deref,
>> + ir_rvalue **offset,
>> + unsigned *const_offset,
>> + bool *row_major,
>> + int *matrix_columns)
>> {
>> - if (!*rvalue)
>> - return;
>> -
>> - ir_dereference *deref = (*rvalue)->as_dereference();
>> - if (!deref)
>> - return;
>> -
>> - ir_variable *var = deref->variable_referenced();
>> - if (!var || !var->is_in_buffer_block())
>> - return;
>> -
>> - mem_ctx = ralloc_parent(*rvalue);
>> -
>> + /* Fix out the name of the interface block */
>
> Maybe 'Fix out' => 'Determine'?
>
OK
>> ir_rvalue *nonconst_block_index;
>> const char *const field_name =
>> interface_field_name(mem_ctx, (char *) var->get_interface_type()->name,
>> deref, &nonconst_block_index);
>>
>> + /* Locate the ubo block by interface name */
>> this->uniform_block = NULL;
>> for (unsigned i = 0; i < shader->NumUniformBlocks; i++) {
>> if (strcmp(field_name, shader->UniformBlocks[i].Name) == 0) {
>> @@ -263,10 +277,10 @@ lower_ubo_reference_visitor::handle_rvalue(ir_rvalue **rvalue)
>>
>> assert(this->uniform_block);
>>
>> - ir_rvalue *offset = new(mem_ctx) ir_constant(0u);
>> - unsigned const_offset = 0;
>> - bool row_major = is_dereferenced_thing_row_major(deref);
>> - int matrix_columns = 1;
>> + *offset = new(mem_ctx) ir_constant(0u);
>> + *const_offset = 0;
>> + *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
>> @@ -275,76 +289,76 @@ lower_ubo_reference_visitor::handle_rvalue(ir_rvalue **rvalue)
>> while (deref) {
>> switch (deref->ir_type) {
>> case ir_type_dereference_variable: {
>> - const_offset += ubo_var->Offset;
>> - deref = NULL;
>> - break;
>> + *const_offset += ubo_var->Offset;
>> + 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_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;
>> + ir_dereference_array *deref_array = (ir_dereference_array *) deref;
>> + unsigned array_stride;
>> + 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;
>> + *matrix_columns = deref_array->array->type->matrix_columns;
>> } else if (deref_array->type->is_interface()) {
>> /* We're processing an array dereference of an interface instance
>> - * array. The thing being dereferenced *must* be a variable
>> - * dereference because intefaces cannot be embedded an 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.
>> + * 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.
>> */
>> assert(deref_array->array->as_dereference_variable());
>> deref = deref_array->array->as_dereference();
>> break;
>> - } else {
>> + } 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
>> + * 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);
>>
>> - array_stride = deref_array->type->std140_size(array_row_major);
>> - array_stride = glsl_align(array_stride, 16);
>> - }
>> + 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 =
>> + 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;
>> + 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;
>> + 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;
>> + 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);
>> + 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);
>>
>> @@ -352,11 +366,12 @@ lower_ubo_reference_visitor::handle_rvalue(ir_rvalue **rvalue)
>>
>> unsigned field_align = type->std140_base_alignment(field_row_major);
>>
>> - intra_struct_offset = glsl_align(intra_struct_offset, field_align);
>> + intra_struct_offset = glsl_align(intra_struct_offset, field_align);
>> +
>> + if (strcmp(struct_type->fields.structure[i].name,
>> + deref_record->field) == 0)
>> + break;
>>
>> - if (strcmp(struct_type->fields.structure[i].name,
>> - deref_record->field) == 0)
>> - break;
>> intra_struct_offset += type->std140_size(field_row_major);
>>
>> /* If the field just examined was itself a structure, apply rule
>> @@ -371,19 +386,49 @@ lower_ubo_reference_visitor::handle_rvalue(ir_rvalue **rvalue)
>> field_align);
>>
>> }
>> - }
>> -
>> - const_offset += intra_struct_offset;
>> + }
>>
>> - deref = deref_record->record->as_dereference();
>> - break;
>> + *const_offset += intra_struct_offset;
>> + deref = deref_record->record->as_dereference();
>> + break;
>> }
>> +
>> default:
>> - assert(!"not reached");
>> - deref = NULL;
>> - break;
>> + assert(!"not reached");
>> + deref = NULL;
>> + break;
>> }
>> }
>> +}
>> +
>> +void
>> +lower_ubo_reference_visitor::handle_rvalue(ir_rvalue **rvalue)
>> +{
>> + if (!*rvalue)
>> + return;
>> +
>> + ir_dereference *deref = (*rvalue)->as_dereference();
>> + if (!deref)
>> + return;
>> +
>> + ir_variable *var = deref->variable_referenced();
>> + if (!var || !var->is_in_buffer_block())
>> + return;
>> +
>> + mem_ctx = ralloc_parent(*rvalue);
>> +
>> + ir_rvalue *offset = NULL;
>> + unsigned const_offset;
>> + bool row_major;
>> + int matrix_columns;
>> +
>> + /* Compute the offset to the start if the dereference as well as other
>> + * information we need to configure the write
>> + */
>> + setup_for_load_or_write(var, deref,
>> + &offset, &const_offset,
>> + &row_major, &matrix_columns);
>> + assert(offset);
>>
>> /* Now that we've calculated the offset to the start of the
>> * dereference, walk over the type and emit loads into a temporary.
>> @@ -401,7 +446,8 @@ lower_ubo_reference_visitor::handle_rvalue(ir_rvalue **rvalue)
>> base_ir->insert_before(assign(load_offset, offset));
>>
>> deref = new(mem_ctx) ir_dereference_variable(load_var);
>> - emit_ubo_loads(deref, load_offset, const_offset, row_major, matrix_columns);
>> + emit_reads_or_writes(false, deref, load_offset, const_offset,
>> + row_major, matrix_columns, 0);
>> *rvalue = deref;
>>
>> progress = true;
>> @@ -420,74 +466,127 @@ lower_ubo_reference_visitor::ubo_load(const glsl_type *type,
>>
>> }
>>
>> +static bool
>> +shader_storage_buffer_object(const _mesa_glsl_parse_state *state)
>> +{
>> + return state->ARB_shader_storage_buffer_object_enable;
>> +}
>> +
>> +ir_call *
>> +lower_ubo_reference_visitor::ssbo_write(ir_rvalue *deref,
>> + ir_rvalue *offset,
>> + unsigned write_mask)
>> +{
>> + exec_list sig_params;
>> +
>> + ir_variable *block_ref = new(mem_ctx)
>> + ir_variable(glsl_type::uint_type, "block_ref" , ir_var_function_in);
>> + sig_params.push_tail(block_ref);
>> +
>> + ir_variable *offset_ref = new(mem_ctx)
>> + ir_variable(glsl_type::uint_type, "offset" , ir_var_function_in);
>> + sig_params.push_tail(offset_ref);
>> +
>> + ir_variable *val_ref = new(mem_ctx)
>> + ir_variable(deref->type, "value" , ir_var_function_in);
>> + sig_params.push_tail(val_ref);
>> +
>> + ir_variable *writemask_ref = new(mem_ctx)
>> + ir_variable(glsl_type::uint_type, "write_mask" , ir_var_function_in);
>> + sig_params.push_tail(writemask_ref);
>> +
>> + ir_function_signature *sig = new(mem_ctx)
>> + ir_function_signature(glsl_type::void_type, shader_storage_buffer_object);
>> + assert(sig);
>> + sig->replace_parameters(&sig_params);
>> + sig->is_intrinsic = true;
>> +
>> + ir_function *f = new(mem_ctx) ir_function("__intrinsic_store_ssbo");
>> + f->add_signature(sig);
>> +
>> + exec_list call_params;
>> + call_params.push_tail(this->uniform_block->clone(mem_ctx, NULL));
>> + call_params.push_tail(offset->clone(mem_ctx, NULL));
>> + call_params.push_tail(deref->clone(mem_ctx, NULL));
>> + call_params.push_tail(new(mem_ctx) ir_constant(write_mask));
>> + return new(mem_ctx) ir_call(sig, NULL, &call_params);
>> +}
>> +
>> +static inline int
>> +writemask_for_size(unsigned n)
>> +{
>> + return ((1 << n) - 1);
>> +}
>> +
>> /**
>> - * Takes LHS and emits a series of assignments into its components
>> - * from the UBO variable at variable_offset + deref_offset.
>> - *
>> - * Recursively calls itself to break the deref down to the point that
>> - * the ir_binop_ubo_load expressions generated are contiguous scalars
>> - * or vectors.
>> + * Takes a deref and recursively calls itself to break the deref down to the
>> + * point that the reads or writes generated are contiguous scalars or vectors.
>> */
>> void
>> -lower_ubo_reference_visitor::emit_ubo_loads(ir_dereference *deref,
>> - ir_variable *base_offset,
>> - unsigned int deref_offset,
>> - bool row_major,
>> - int matrix_columns)
>> +lower_ubo_reference_visitor::emit_reads_or_writes(bool is_write,
>> + ir_dereference *deref,
>> + ir_variable *base_offset,
>> + unsigned int deref_offset,
>> + bool row_major,
>> + int matrix_columns,
>> + unsigned write_mask)
>> {
>> if (deref->type->is_record()) {
>> unsigned int field_offset = 0;
>>
>> for (unsigned i = 0; i < deref->type->length; i++) {
>> - const struct glsl_struct_field *field =
>> - &deref->type->fields.structure[i];
>> - ir_dereference *field_deref =
>> - new(mem_ctx) ir_dereference_record(deref->clone(mem_ctx, NULL),
>> - field->name);
>> -
>> - field_offset =
>> - glsl_align(field_offset,
>> + const struct glsl_struct_field *field =
>> + &deref->type->fields.structure[i];
>> + ir_dereference *field_deref =
>> + new(mem_ctx) ir_dereference_record(deref->clone(mem_ctx, NULL),
>> + field->name);
>> +
>> + field_offset =
>> + glsl_align(field_offset,
>> field->type->std140_base_alignment(row_major));
>>
>> - emit_ubo_loads(field_deref, base_offset, deref_offset + field_offset,
>> - row_major, 1);
>> + emit_reads_or_writes(is_write, field_deref, base_offset,
>> + deref_offset + field_offset,
>> + row_major, 1,
>> + writemask_for_size(field_deref->type->vector_elements));
>>
>> - field_offset += field->type->std140_size(row_major);
>> + field_offset += field->type->std140_size(row_major);
>
> Tab issue here?
Yeah, it seems.
>
> With changes Reviewed-by: Jordan Justen <jordan.l.justen at intel.com>
>
Thanks!
Sam
>> }
>> return;
>> }
>>
>> if (deref->type->is_array()) {
>> unsigned array_stride =
>> - glsl_align(deref->type->fields.array->std140_size(row_major),
>> - 16);
>> + glsl_align(deref->type->fields.array->std140_size(row_major), 16);
>>
>> for (unsigned i = 0; i < deref->type->length; i++) {
>> - ir_constant *element = new(mem_ctx) ir_constant(i);
>> - ir_dereference *element_deref =
>> - new(mem_ctx) ir_dereference_array(deref->clone(mem_ctx, NULL),
>> - element);
>> - emit_ubo_loads(element_deref, base_offset,
>> - deref_offset + i * array_stride,
>> - row_major, 1);
>> + ir_constant *element = new(mem_ctx) ir_constant(i);
>> + ir_dereference *element_deref =
>> + new(mem_ctx) ir_dereference_array(deref->clone(mem_ctx, NULL),
>> + element);
>> + emit_reads_or_writes(is_write, element_deref, base_offset,
>> + deref_offset + i * array_stride,
>> + row_major, 1,
>> + writemask_for_size(element_deref->type->vector_elements));
>> }
>> return;
>> }
>>
>> if (deref->type->is_matrix()) {
>> for (unsigned i = 0; i < deref->type->matrix_columns; i++) {
>> - ir_constant *col = new(mem_ctx) ir_constant(i);
>> - ir_dereference *col_deref =
>> - new(mem_ctx) ir_dereference_array(deref->clone(mem_ctx, NULL),
>> - col);
>> + ir_constant *col = new(mem_ctx) ir_constant(i);
>> + ir_dereference *col_deref =
>> + new(mem_ctx) ir_dereference_array(deref->clone(mem_ctx, NULL), col);
>>
>> if (row_major) {
>> /* For a row-major matrix, the next column starts at the next
>> * element.
>> */
>> int size_mul = deref->type->is_double() ? 8 : 4;
>> - emit_ubo_loads(col_deref, base_offset, deref_offset + i * size_mul,
>> - row_major, deref->type->matrix_columns);
>> + emit_reads_or_writes(is_write, col_deref, base_offset,
>> + deref_offset + i * size_mul,
>> + row_major, deref->type->matrix_columns,
>> + writemask_for_size(col_deref->type->vector_elements));
>> } else {
>> /* std140 always rounds the stride of arrays (and matrices) to a
>> * vec4, so matrices are always 16 between columns/rows. With
>> @@ -495,21 +594,25 @@ lower_ubo_reference_visitor::emit_ubo_loads(ir_dereference *deref,
>> */
>> int size_mul = (deref->type->is_double() &&
>> deref->type->vector_elements > 2) ? 32 : 16;
>> - emit_ubo_loads(col_deref, base_offset, deref_offset + i * size_mul,
>> - row_major, deref->type->matrix_columns);
>> + emit_reads_or_writes(is_write, col_deref, base_offset,
>> + deref_offset + i * size_mul,
>> + row_major, deref->type->matrix_columns,
>> + writemask_for_size(col_deref->type->vector_elements));
>> }
>> }
>> return;
>> }
>>
>> - assert(deref->type->is_scalar() ||
>> - deref->type->is_vector());
>> + assert(deref->type->is_scalar() || deref->type->is_vector());
>>
>> if (!row_major) {
>> - ir_rvalue *offset = add(base_offset,
>> - new(mem_ctx) ir_constant(deref_offset));
>> - base_ir->insert_before(assign(deref->clone(mem_ctx, NULL),
>> - ubo_load(deref->type, offset)));
>> + ir_rvalue *offset =
>> + add(base_offset, new(mem_ctx) ir_constant(deref_offset));
>> + if (is_write)
>> + base_ir->insert_after(ssbo_write(deref, offset, write_mask));
>> + else
>> + base_ir->insert_before(assign(deref->clone(mem_ctx, NULL),
>> + ubo_load(deref->type, offset)));
>> } else {
>> unsigned N = deref->type->is_double() ? 8 : 4;
>>
>> @@ -527,22 +630,100 @@ lower_ubo_reference_visitor::emit_ubo_loads(ir_dereference *deref,
>> assert(matrix_columns <= 4);
>> unsigned matrix_stride = glsl_align(matrix_columns * N, 16);
>>
>> - const glsl_type *ubo_type = deref->type->base_type == GLSL_TYPE_FLOAT ?
>> + const glsl_type *deref_type = deref->type->base_type == GLSL_TYPE_FLOAT ?
>> glsl_type::float_type : glsl_type::double_type;
>>
>> for (unsigned i = 0; i < deref->type->vector_elements; i++) {
>> - ir_rvalue *chan_offset =
>> - add(base_offset,
>> - new(mem_ctx) ir_constant(deref_offset + i * matrix_stride));
>> -
>> - base_ir->insert_before(assign(deref->clone(mem_ctx, NULL),
>> - ubo_load(ubo_type,
>> - chan_offset),
>> - (1U << i)));
>> + ir_rvalue *chan_offset =
>> + add(base_offset,
>> + new(mem_ctx) ir_constant(deref_offset + i * matrix_stride));
>> + if (is_write) {
>> + base_ir->insert_after(ssbo_write(swizzle(deref, i, 1), chan_offset, 1));
>> + } else {
>> + base_ir->insert_before(assign(deref->clone(mem_ctx, NULL),
>> + ubo_load(deref_type, chan_offset),
>> + (1U << i)));
>> + }
>> }
>> }
>> }
>>
>> +void
>> +lower_ubo_reference_visitor::write_to_memory(ir_dereference *deref,
>> + ir_variable *var,
>> + ir_variable *write_var,
>> + unsigned write_mask)
>> +{
>> + ir_rvalue *offset = NULL;
>> + unsigned const_offset;
>> + bool row_major;
>> + int matrix_columns;
>> +
>> + /* Compute the offset to the start if the dereference as well as other
>> + * information we need to configure the write
>> + */
>> + setup_for_load_or_write(var, deref,
>> + &offset, &const_offset,
>> + &row_major, &matrix_columns);
>> + assert(offset);
>> +
>> + /* Now emit writes from the temporary to memory */
>> + ir_variable *write_offset =
>> + new(mem_ctx) ir_variable(glsl_type::uint_type,
>> + "ssbo_write_temp_offset",
>> + ir_var_temporary);
>> +
>> + base_ir->insert_before(write_offset);
>> + base_ir->insert_before(assign(write_offset, offset));
>> +
>> + deref = new(mem_ctx) ir_dereference_variable(write_var);
>> + emit_reads_or_writes(true, deref, write_offset, const_offset,
>> + row_major, matrix_columns, write_mask);
>> +}
>> +
>> +void
>> +lower_ubo_reference_visitor::check_for_ssbo_write(ir_assignment *ir)
>> +{
>> + if (!ir || !ir->lhs)
>> + return;
>> +
>> + ir_rvalue *rvalue = ir->lhs->as_rvalue();
>> + if (!rvalue)
>> + return;
>> +
>> + ir_dereference *deref = ir->lhs->as_dereference();
>> + if (!deref)
>> + return;
>> +
>> + ir_variable *var = ir->lhs->variable_referenced();
>> + if (!var || !var->is_in_buffer_block())
>> + return;
>> +
>> + /* We have a write to a buffer variable, so declare a temporary and rewrite
>> + * the assignment so that the temporary is the LHS.
>> + */
>> + mem_ctx = ralloc_parent(shader->ir);
>> +
>> + const glsl_type *type = rvalue->type;
>> + ir_variable *write_var = new(mem_ctx) ir_variable(type,
>> + "ssbo_write_temp",
>> + ir_var_temporary);
>> + base_ir->insert_before(write_var);
>> + ir->lhs = new(mem_ctx) ir_dereference_variable(write_var);
>> +
>> + /* Now we have to write the value assigned to the temporary back to memory */
>> + write_to_memory(deref, var, write_var, ir->write_mask);
>> + progress = true;
>> +}
>> +
>> +
>> +ir_visitor_status
>> +lower_ubo_reference_visitor::visit_enter(ir_assignment *ir)
>> +{
>> + check_for_ssbo_write(ir);
>> + return rvalue_visit(ir);
>> +}
>> +
>> } /* unnamed namespace */
>>
>> void
>> --
>> 1.9.1
>>
>
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