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/*
* 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_shader *nir, 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.
*/
const struct glsl_type *type = var->type;
if (nir_is_per_vertex_io(var, nir->stage))
type = glsl_get_array_element(type);
assert(glsl_type_is_array(type));
return glsl_get_length(type);
}
/**
* Update the type of the combined array (including interface block nesting).
*/
static void
update_type(nir_variable *var, gl_shader_stage stage, unsigned length)
{
const struct glsl_type *type = glsl_array_type(glsl_float_type(), length);
if (nir_is_per_vertex_io(var, stage))
type = glsl_array_type(type, glsl_get_length(var->type));
var->type = 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);
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(nir, clip);
const unsigned cull_array_size = get_unwrapped_array_length(nir, cull);
if (store_info) {
nir->info->clip_distance_array_size = clip_array_size;
nir->info->cull_distance_array_size = cull_array_size;
}
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 */
update_type(clip, nir->stage, 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, true);
if (nir->stage > MESA_SHADER_VERTEX)
combine_clip_cull(nir, &nir->inputs, false);
}
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