--- /dev/null
+/*
+ * 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);
+}
projects / mesa.git / commitdiff