[Mesa-dev] [PATCH 2/7] nir: add varying component packing helpers
Bas Nieuwenhuizen
bas at basnieuwenhuizen.nl
Sat Oct 28 14:14:34 UTC 2017
On Mon, Oct 23, 2017 at 2:10 AM, Timothy Arceri <tarceri at itsqueeze.com> wrote:
> ---
> src/compiler/nir/nir.h | 2 +
> src/compiler/nir/nir_linking_helpers.c | 235 +++++++++++++++++++++++++++++++++
> 2 files changed, 237 insertions(+)
>
> diff --git a/src/compiler/nir/nir.h b/src/compiler/nir/nir.h
> index dd833cf183..6a761ab655 100644
> --- a/src/compiler/nir/nir.h
> +++ b/src/compiler/nir/nir.h
> @@ -2413,20 +2413,22 @@ void nir_lower_io_to_temporaries(nir_shader *shader,
> nir_function_impl *entrypoint,
> bool outputs, bool inputs);
>
> void nir_shader_gather_info(nir_shader *shader, nir_function_impl *entrypoint);
>
> void nir_assign_var_locations(struct exec_list *var_list, unsigned *size,
> int (*type_size)(const struct glsl_type *));
>
> /* Some helpers to do very simple linking */
> bool nir_remove_unused_varyings(nir_shader *producer, nir_shader *consumer);
> +void nir_compact_varyings(nir_shader *producer, nir_shader *consumer,
> + bool default_to_smooth_interp);
>
> typedef enum {
> /* If set, this forces all non-flat fragment shader inputs to be
> * interpolated as if with the "sample" qualifier. This requires
> * nir_shader_compiler_options::use_interpolated_input_intrinsics.
> */
> nir_lower_io_force_sample_interpolation = (1 << 1),
> } nir_lower_io_options;
> bool nir_lower_io(nir_shader *shader,
> nir_variable_mode modes,
> diff --git a/src/compiler/nir/nir_linking_helpers.c b/src/compiler/nir/nir_linking_helpers.c
> index 54ba1c85e5..85da84fbd9 100644
> --- a/src/compiler/nir/nir_linking_helpers.c
> +++ b/src/compiler/nir/nir_linking_helpers.c
> @@ -143,10 +143,245 @@ nir_remove_unused_varyings(nir_shader *producer, nir_shader *consumer)
> tcs_add_output_reads(producer, read);
>
> bool progress = false;
> progress = remove_unused_io_vars(producer, &producer->outputs, read);
>
> progress =
> remove_unused_io_vars(consumer, &consumer->inputs, written) || progress;
>
> return progress;
> }
> +
> +static uint8_t
> +get_interp_type(nir_variable *var, bool default_to_smooth_interp)
> +{
> + return var->data.interpolation == INTERP_MODE_NONE &&
> + default_to_smooth_interp ?
> + INTERP_MODE_SMOOTH : var->data.interpolation;
> +}
> +
> +static void
> +get_slot_component_masks_and_interp_types(struct exec_list *var_list,
> + uint8_t *comps, uint8_t *interp_type,
> + gl_shader_stage stage,
> + bool default_to_smooth_interp)
> +{
> + nir_foreach_variable_safe(var, var_list) {
> + assert(var->data.location >= 0);
> +
> + /* Only remap things that aren't built-ins.
> + * TODO: add TES patch support.
> + */
> + if (var->data.location >= VARYING_SLOT_VAR0 &&
> + var->data.location - VARYING_SLOT_VAR0 < 32) {
> +
> + const struct glsl_type *type = var->type;
> + if (nir_is_per_vertex_io(var, stage)) {
> + assert(glsl_type_is_array(type));
> + type = glsl_get_array_element(type);
> + }
> +
> + unsigned location = var->data.location - VARYING_SLOT_VAR0;
> + unsigned elements =
> + glsl_get_vector_elements(glsl_without_array(type));
> +
> + bool dual_slot = glsl_type_is_dual_slot(glsl_without_array(type));
> + unsigned slots = glsl_count_attribute_slots(type, false);
> + for (unsigned i = 0; i < slots; i++) {
> + interp_type[location + i] =
> + get_interp_type(var, default_to_smooth_interp);
> +
> + if (dual_slot) {
> + unsigned comps_slot2 = 0;
I'd expect this to be declared outside the loop, otherwise it is
always going to be 0 in the (i & 1) case below.
With that fixed this patch is
Reviewed-by: Bas Nieuwenhuizen <bas at basnieuwenhuizen.nl>
> + if (i & 1) {
> + comps[location + i] |= ((1 << comps_slot2) - 1);
> + } else {
> + unsigned num_comps = 4 - var->data.location_frac;
> + comps_slot2 = (elements * 2) - num_comps;
> +
> + /* Assume ARB_enhanced_layouts packing rules for doubles */
> + assert(var->data.location_frac == 0 ||
> + var->data.location_frac == 2);
> + assert(comps_slot2 <= 4);
> +
> + comps[location + i] |=
> + ((1 << num_comps) - 1) << var->data.location_frac;
> + }
> + } else {
> + comps[location + i] |=
> + ((1 << elements) - 1) << var->data.location_frac;
> + }
> + }
> + }
> + }
> +}
> +
> +struct varying_loc
> +{
> + uint8_t component;
> + uint32_t location;
> +};
> +
> +static void
> +remap_slots_and_components(struct exec_list *var_list,
> + struct varying_loc (*remap)[4])
> +{
> + nir_foreach_variable(var, var_list) {
> + assert(var->data.location >= 0);
> +
> + /* Only remap things that aren't built-ins */
> + if (var->data.location >= VARYING_SLOT_VAR0 &&
> + var->data.location - VARYING_SLOT_VAR0 < 32) {
> + assert(var->data.location - VARYING_SLOT_VAR0 < 32);
> + assert(remap[var->data.location - VARYING_SLOT_VAR0] >= 0);
> +
> + unsigned location = var->data.location - VARYING_SLOT_VAR0;
> + struct varying_loc *new_loc = &remap[location][var->data.location_frac];
> + if (new_loc->location) {
> + var->data.location = new_loc->location;
> + var->data.location_frac = new_loc->component;
> + }
> + }
> + }
> +}
> +
> +/* If there are empty components in the slot compact the remaining components
> + * as close to component 0 as possible. This will make it easier to fill the
> + * empty components with components from a different slot in a following pass.
> + */
> +static void
> +compact_components(nir_shader *producer, nir_shader *consumer, uint8_t *comps,
> + uint8_t *interp_type, bool default_to_smooth_interp)
> +{
> + struct exec_list *input_list = &consumer->inputs;
> + struct exec_list *output_list = &producer->outputs;
> + struct varying_loc remap[32][4] = {{{0}, {0}}};
> +
> + /* Create a cursor for each interpolation type */
> + unsigned cursor[4] = {0};
> +
> + /* We only need to pass over one stage and we choose the consumer as it seems
> + * to cause a larger reduction in instruction counts (tested on i965).
> + */
> + nir_foreach_variable(var, input_list) {
> +
> + /* Only remap things that aren't builtins.
> + * TODO: add TES patch support.
> + */
> + if (var->data.location >= VARYING_SLOT_VAR0 &&
> + var->data.location - VARYING_SLOT_VAR0 < 32) {
> +
> + const struct glsl_type *type = var->type;
> + if (nir_is_per_vertex_io(var, consumer->info.stage)) {
> + assert(glsl_type_is_array(type));
> + type = glsl_get_array_element(type);
> + }
> +
> + /* Skip types that require more complex packing handling.
> + * TODO: add support for these types.
> + */
> + if (glsl_type_is_array(type) ||
> + glsl_type_is_dual_slot(type) ||
> + glsl_type_is_matrix(type) ||
> + glsl_type_is_struct(type) ||
> + glsl_type_is_64bit(type))
> + continue;
> +
> + /* We ignore complex types above and all other vector types should
> + * have been split into scalar variables by the lower_io_to_scalar
> + * pass. The only exeption should by OpenGL xfb varyings.
> + */
> + if (glsl_get_vector_elements(type) != 1)
> + continue;
> +
> + unsigned location = var->data.location - VARYING_SLOT_VAR0;
> + uint8_t used_comps = comps[location];
> +
> + /* If there are no empty components there is nothing more for us to do.
> + */
> + if (used_comps == 0xf)
> + continue;
> +
> + bool found_new_offset = false;
> + uint8_t interp = get_interp_type(var, default_to_smooth_interp);
> + for (; cursor[interp] < 32; cursor[interp]++) {
> +
> + /* We couldn't find anywhere to pack the varying continue on. */
> + if (cursor[interp] == location)
> + break;
> +
> + /* We can only pack varyings with matching interpolation types */
> + if (interp_type[cursor[interp]] != interp)
> + continue;
> +
> + uint8_t cursor_used_comps = comps[cursor[interp]];
> +
> + /* If the slot is empty just skip it for now, compact_var_list()
> + * can be called after this function to remove empty slots for us.
> + * TODO: finish implementing compact_var_list() requires array and
> + * matrix splitting.
> + */
> + if (!cursor_used_comps)
> + continue;
> +
> + uint8_t unused_comps = ~cursor_used_comps;
> +
> + for (unsigned i = 0; i < 4; i++) {
> + uint8_t new_var_comps = 1 << i;
> + if (unused_comps & new_var_comps) {
> + remap[location][var->data.location_frac].component = i;
> + remap[location][var->data.location_frac].location =
> + cursor[interp] + VARYING_SLOT_VAR0;
> +
> + found_new_offset = true;
> +
> + /* Turn off the mask for the component we are remapping */
> + if (comps[location] & 1 << var->data.location_frac) {
> + comps[location] ^= 1 << var->data.location_frac;
> + comps[cursor[interp]] |= new_var_comps;
> + }
> + break;
> + }
> + }
> +
> + if (found_new_offset)
> + break;
> + }
> + }
> + }
> +
> + remap_slots_and_components(input_list, remap);
> + remap_slots_and_components(output_list, remap);
> +}
> +
> +/* We assume that this has been called more-or-less directly after
> + * remove_unused_varyings. At this point, all of the varyings that we
> + * aren't going to be using have been completely removed and the
> + * inputs_read and outputs_written fields in nir_shader_info reflect
> + * this. Therefore, the total set of valid slots is the OR of the two
> + * sets of varyings; this accounts for varyings which one side may need
> + * to read/write even if the other doesn't. This can happen if, for
> + * instance, an array is used indirectly from one side causing it to be
> + * unsplittable but directly from the other.
> + */
> +void
> +nir_compact_varyings(nir_shader *producer, nir_shader *consumer,
> + bool default_to_smooth_interp)
> +{
> + assert(producer->info.stage != MESA_SHADER_FRAGMENT);
> + assert(consumer->info.stage != MESA_SHADER_VERTEX);
> +
> + uint8_t comps[32] = {0};
> + uint8_t interp_type[32] = {0};
> +
> + get_slot_component_masks_and_interp_types(&producer->outputs, comps,
> + interp_type,
> + producer->info.stage,
> + default_to_smooth_interp);
> + get_slot_component_masks_and_interp_types(&consumer->inputs, comps,
> + interp_type,
> + consumer->info.stage,
> + default_to_smooth_interp);
> +
> + compact_components(producer, consumer, comps, interp_type,
> + default_to_smooth_interp);
> +}
> --
> 2.13.6
>
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