[Mesa-dev] [PATCH 07/14] nir: add a pass to compact clip/cull distances.
Jason Ekstrand
jason at jlekstrand.net
Thu Nov 17 04:37:50 UTC 2016
On Mon, Nov 14, 2016 at 5:41 PM, Kenneth Graunke <kenneth at whitecape.org>
wrote:
> Signed-off-by: Kenneth Graunke <kenneth at whitecape.org>
> ---
> src/compiler/Makefile.sources | 1 +
> src/compiler/nir/nir.h | 1 +
> .../nir/nir_lower_clip_cull_distance_arrays.c | 187
> +++++++++++++++++++++
> 3 files changed, 189 insertions(+)
> create mode 100644 src/compiler/nir/nir_lower_clip_cull_distance_arrays.c
>
> diff --git a/src/compiler/Makefile.sources b/src/compiler/Makefile.sources
> index 08d93e0..6c331b0 100644
> --- a/src/compiler/Makefile.sources
> +++ b/src/compiler/Makefile.sources
> @@ -202,6 +202,7 @@ NIR_FILES = \
> nir/nir_lower_bitmap.c \
> nir/nir_lower_clamp_color_outputs.c \
> nir/nir_lower_clip.c \
> + nir/nir_lower_clip_cull_distance_arrays.c \
> nir/nir_lower_double_ops.c \
> nir/nir_lower_double_packing.c \
> nir/nir_lower_drawpixels.c \
> diff --git a/src/compiler/nir/nir.h b/src/compiler/nir/nir.h
> index 0b78242..f3aadb9 100644
> --- a/src/compiler/nir/nir.h
> +++ b/src/compiler/nir/nir.h
> @@ -2441,6 +2441,7 @@ bool nir_lower_idiv(nir_shader *shader);
>
> void nir_lower_clip_vs(nir_shader *shader, unsigned ucp_enables);
> void nir_lower_clip_fs(nir_shader *shader, unsigned ucp_enables);
> +void nir_lower_clip_cull_distance_arrays(nir_shader *nir);
>
> void nir_lower_two_sided_color(nir_shader *shader);
>
> diff --git a/src/compiler/nir/nir_lower_clip_cull_distance_arrays.c
> b/src/compiler/nir/nir_lower_clip_cull_distance_arrays.c
> new file mode 100644
> index 0000000..9f8a7de
> --- /dev/null
> +++ b/src/compiler/nir/nir_lower_clip_cull_distance_arrays.c
> @@ -0,0 +1,187 @@
> +/*
> + * Copyright © 2015 Intel Corporation
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a
> + * copy of this software and associated documentation files (the
> "Software"),
> + * to deal in the Software without restriction, including without
> limitation
> + * the rights to use, copy, modify, merge, publish, distribute,
> sublicense,
> + * and/or sell copies of the Software, and to permit persons to whom the
> + * Software is furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice (including the
> next
> + * paragraph) shall be included in all copies or substantial portions of
> the
> + * Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
> EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
> MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
> SHALL
> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
> OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
> + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
> DEALINGS
> + * IN THE SOFTWARE.
> + */
> +
> +#include "nir.h"
> +#include "nir_builder.h"
> +
> +/**
> + * @file
> + *
> + * This pass combines separate clip and cull distance arrays into a
> + * single array that contains both. Clip distances come first, then
> + * cull distances. It also populates nir_shader_info with the size
> + * of the original arrays so the driver knows which are which.
> + */
> +
> +/**
> + * Get the length of the clip/cull distance array, looking past
> + * any interface block arrays.
> + */
> +static unsigned
> +get_unwrapped_array_length(nir_variable *var)
> +{
> + if (!var)
> + return 0;
> +
> + /* Unwrap GS input and TCS input/output interfaces. We want the
> + * underlying clip/cull distance array length, not the per-vertex
> + * array length.
> + */
>
Probably not needed, but we could put some stage-based asserts in here.
> + const struct glsl_type *type = var->type;
> + if (glsl_type_is_array_of_arrays(type))
> + type = glsl_get_array_element(type);
> +
> + return glsl_get_length(type);
> +}
> +
> +/**
> + * Get the type of the combined array (including interface block nesting).
> + */
> +static const struct glsl_type *
> +get_new_array_type(const struct glsl_type *old_type, unsigned length)
> +{
> + const struct glsl_type *type = glsl_array_type(glsl_float_type(),
> length);
> +
> + if (glsl_type_is_array_of_arrays(old_type))
> + type = glsl_array_type(type, glsl_get_length(type));
> +
> + return type;
> +}
> +
> +/**
> + * Rewrite any clip/cull distances to refer to the new combined array.
> + */
> +static void
> +rewrite_references(nir_instr *instr,
> + nir_variable *combined,
> + unsigned cull_offset)
> +{
> + if (instr->type != nir_instr_type_intrinsic)
> + return;
> +
> + nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr);
> +
> + /* copy_var needs to be lowered to load/store before calling this pass
> */
> + assert(intrin->intrinsic != nir_intrinsic_copy_var);
>
Wouldn't be that hard to make it support it, but sure.
> +
> + if (intrin->intrinsic != nir_intrinsic_load_var &&
> + intrin->intrinsic != nir_intrinsic_store_var)
> + return;
> +
> + nir_deref_var *var_ref = intrin->variables[0];
> + if (var_ref->var->data.mode != combined->data.mode)
> + return;
> +
> + if (var_ref->var->data.location != VARYING_SLOT_CLIP_DIST0 &&
> + var_ref->var->data.location != VARYING_SLOT_CULL_DIST0)
> + return;
> +
> + /* Update types along the deref chain */
> + const struct glsl_type *type = combined->type;
> + nir_deref *deref = &var_ref->deref;
> + while (deref) {
> + deref->type = type;
> + deref = deref->child;
> + type = glsl_get_array_element(type);
> + }
> +
> + /* For cull distances, add an offset to the array index */
> + if (var_ref->var->data.location == VARYING_SLOT_CULL_DIST0) {
> + nir_deref *tail = nir_deref_tail(&intrin->variables[0]->deref);
> + nir_deref_array *array_ref = nir_deref_as_array(tail);
> +
> + array_ref->base_offset += cull_offset;
> + }
> +
> + /* Point the deref at the combined array */
> + var_ref->var = combined;
> +
> + /* There's no need to update writemasks; it's a scalar array. */
> +}
> +
> +static void
> +combine_clip_cull(nir_shader *nir,
> + struct exec_list *vars,
> + bool store_info)
> +{
> + nir_variable *cull = NULL;
> + nir_variable *clip = NULL;
> +
> + nir_foreach_variable(var, vars) {
> + if (var->data.location == VARYING_SLOT_CLIP_DIST0)
> + clip = var;
> +
> + if (var->data.location == VARYING_SLOT_CULL_DIST0)
> + cull = var;
> + }
> +
> + const unsigned clip_array_size = get_unwrapped_array_length(clip);
> + const unsigned cull_array_size = get_unwrapped_array_length(cull);
> +
> + if (store_info) {
> + nir->info->clip_distance_array_size = clip_array_size;
> + nir->info->cull_distance_array_size = cull_array_size;
>
Why is this optional? If the sizes here and in the info ever differ,
you're going to have a problem.
> + }
> +
> + if (clip)
> + clip->data.compact = true;
> +
> + if (cull)
> + cull->data.compact = true;
> +
> + if (cull_array_size > 0) {
> + if (clip_array_size == 0) {
> + /* No clip distances, just change the cull distance location */
> + cull->data.location = VARYING_SLOT_CLIP_DIST0;
> + } else {
> + /* Turn the ClipDistance array into a combined one */
> + clip->type = get_new_array_type(clip->type,
> + clip_array_size +
> cull_array_size);
> +
> + /* Rewrite CullDistance to reference the combined array */
> + nir_foreach_function(function, nir) {
> + if (function->impl) {
> + nir_foreach_block(block, function->impl) {
> + nir_foreach_instr(instr, block) {
> + rewrite_references(instr, clip, clip_array_size);
> + }
> + }
> + }
> + }
> +
> + /* Delete the old CullDistance variable */
> + exec_node_remove(&cull->node);
> + ralloc_free(cull);
> + }
> + }
> +}
> +
> +void
> +nir_lower_clip_cull_distance_arrays(nir_shader *nir)
> +{
> + if (nir->stage <= MESA_SHADER_GEOMETRY)
> + combine_clip_cull(nir, &nir->outputs, &nir->info);
> +
> + if (nir->stage > MESA_SHADER_VERTEX)
> + combine_clip_cull(nir, &nir->inputs, NULL);
> +}
> --
> 2.10.2
>
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