[Mesa-dev] [PATCH 27/74] glsl: Lower shader storage buffer object writes to ir_ssbo_store
Iago Toral
itoral at igalia.com
Mon May 18 23:15:06 PDT 2015
On Mon, 2015-05-18 at 15:58 -0700, Jordan Justen wrote:
> On 2015-05-14 07:06:30, Iago Toral Quiroga wrote:
> > Extend the existing lower_ubo_reference pass to also detect SSBO writes
> > and lower them to ir_ssbo_store nodes.
> > ---
> > src/glsl/lower_ubo_reference.cpp | 412 +++++++++++++++++++++++++++++++--------
> > 1 file changed, 336 insertions(+), 76 deletions(-)
> >
> > diff --git a/src/glsl/lower_ubo_reference.cpp b/src/glsl/lower_ubo_reference.cpp
> > index fb8a890..8cb28f5 100644
> > --- a/src/glsl/lower_ubo_reference.cpp
> > +++ b/src/glsl/lower_ubo_reference.cpp
> > @@ -139,12 +139,34 @@ public:
> > }
> >
> > void handle_rvalue(ir_rvalue **rvalue);
> > + ir_visitor_status visit_enter(ir_assignment *ir);
> > +
> > + void setup_for_load_or_write(ir_variable *var,
> > + ir_dereference *deref,
> > + ir_rvalue **offset,
> > + unsigned *const_offset,
> > + bool *row_major,
> > + int *matrix_columns,
> > + bool *is_buffer);
> > +
> > void emit_ubo_loads(ir_dereference *deref, ir_variable *base_offset,
> > unsigned int deref_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);
> > + void write_to_memory(ir_dereference *deref,
> > + ir_variable *var,
> > + ir_variable *write_var,
> > + unsigned write_mask);
> > + void emit_ssbo_writes(ir_dereference *deref, ir_variable *base_offset,
> > + unsigned int deref_offset, bool row_major,
> > + int matrix_columns, unsigned write_mask);
> > + ir_ssbo_store *ssbo_write(ir_rvalue *deref, ir_rvalue *offset,
> > + unsigned write_mask);
> > +
> > void *mem_ctx;
> > struct gl_shader *shader;
> > struct gl_uniform_buffer_variable *ubo_var;
> > @@ -219,26 +241,21 @@ 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,
> > + bool *is_buffer)
> > {
> > - if (!*rvalue)
> > - return;
> > -
> > - ir_dereference *deref = (*rvalue)->as_dereference();
> > - if (!deref)
> > - return;
> > -
> > - ir_variable *var = deref->variable_referenced();
> > - if (!var || !var->is_in_uniform_block())
> > - return;
> > -
> > - mem_ctx = ralloc_parent(*rvalue);
> > -
> > + /* Fix out the name of the interface block*/
> > 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) {
> > @@ -253,10 +270,7 @@ lower_ubo_reference_visitor::handle_rvalue(ir_rvalue **rvalue)
> > this->uniform_block = index;
> > }
> >
> > - if (shader->UniformBlocks[i].IsBuffer)
> > - this->opcode = ir_binop_ssbo_load;
> > - else
> > - this->opcode = ir_binop_ubo_load;
> > + *is_buffer = shader->UniformBlocks[i].IsBuffer;
> >
> > struct gl_uniform_block *block = &shader->UniformBlocks[i];
> >
> > @@ -269,10 +283,10 @@ 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
> > @@ -281,76 +295,76 @@ 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);
> >
> > @@ -358,11 +372,12 @@ 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
> > @@ -377,19 +392,56 @@ 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_uniform_block())
> > + return;
> > +
> > + mem_ctx = ralloc_parent(*rvalue);
> > +
> > + ir_rvalue *offset = NULL;
> > + unsigned const_offset;
> > + bool row_major;
> > + int matrix_columns;
> > + bool is_buffer;
> > +
> > + /* 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,
> > + &is_buffer);
> > + assert(offset);
> > +
> > + if (is_buffer)
> > + this->opcode = ir_binop_ssbo_load;
> > + else
> > + this->opcode = ir_binop_ubo_load;
> >
> > /* Now that we've calculated the offset to the start of the
> > * dereference, walk over the type and emit loads into a temporary.
> > @@ -549,6 +601,214 @@ lower_ubo_reference_visitor::emit_ubo_loads(ir_dereference *deref,
> > }
> > }
> >
> > +ir_ssbo_store *
> > +lower_ubo_reference_visitor::ssbo_write(ir_rvalue *deref,
> > + ir_rvalue *offset,
> > + unsigned write_mask)
> > +{
> > + ir_rvalue *block_ref = this->uniform_block->clone(mem_ctx, NULL);
> > + ir_rvalue *val_ref = deref->clone(mem_ctx, NULL);
> > + return new(mem_ctx) ir_ssbo_store(block_ref, offset, val_ref, write_mask);
> > +}
> > +
> > +static inline int
> > +writemask_for_size(unsigned n)
> > +{
> > + return ((1 << n) - 1);
> > +}
> > +
> > +void
> > +lower_ubo_reference_visitor::emit_ssbo_writes(ir_dereference *deref,
> > + ir_variable *base_offset,
> > + unsigned int deref_offset,
> > + bool row_major,
> > + int matrix_columns,
> > + unsigned write_mask)
> > +{
>
> This code seems to be mostly a duplicate of the load case. Wouldn't
> this leave us with two mostly similar complex code paths?
>
> Maybe the low level emit could switch based on the opcode?
>
> -Jordan
Yeah, good point. I'll do that.
Iago
> > + 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,
> > + field->type->std140_base_alignment(row_major));
> > +
> > + emit_ssbo_writes(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);
> > + }
> > + return;
> > + }
> > +
> > + if (deref->type->is_array()) {
> > + unsigned array_stride =
> > + 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_ssbo_writes(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);
> > +
> > + 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_ssbo_writes(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
> > + * doubles, they will be 32 apart when there are more than 2 rows.
> > + */
> > + int size_mul = (deref->type->is_double() &&
> > + deref->type->vector_elements > 2) ? 32 : 16;
> > + emit_ssbo_writes(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());
> > +
> > + if (!row_major) {
> > + ir_rvalue *offset =
> > + add(base_offset, new(mem_ctx) ir_constant(deref_offset));
> > + base_ir->insert_after(ssbo_write(deref, offset, write_mask));
> > + } else {
> > + unsigned N = deref->type->is_double() ? 8 : 4;
> > +
> > + /* We're dereffing a column out of a row-major matrix, so we
> > + * gather the vector from each stored row.
> > + */
> > + assert(deref->type->base_type == GLSL_TYPE_FLOAT ||
> > + deref->type->base_type == GLSL_TYPE_DOUBLE);
> > + /* Matrices, row_major or not, are stored as if they were
> > + * arrays of vectors of the appropriate size in std140.
> > + * Arrays have their strides rounded up to a vec4, so the
> > + * matrix stride is always 16. However a double matrix may either be 16
> > + * or 32 depending on the number of columns.
> > + */
> > + assert(matrix_columns <= 4);
> > + unsigned matrix_stride = glsl_align(matrix_columns * N, 16);
> > +
> > + 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_after(ssbo_write(swizzle(deref, i, 1), chan_offset, 1));
> > + }
> > + }
> > +}
> > +
> > +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;
> > + bool is_buffer;
> > +
> > + /* 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,
> > + &is_buffer);
> > + assert(offset);
> > + assert(is_buffer);
> > +
> > + /* 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_ssbo_writes(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_uniform_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(rvalue);
> > +
> > + 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
> >
> > _______________________________________________
> > mesa-dev mailing list
> > mesa-dev at lists.freedesktop.org
> > http://lists.freedesktop.org/mailman/listinfo/mesa-dev
>
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