--- /dev/null
+/*
+ * Copyright © 2017 Timothy Arceri
+ *
+ * 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 nir_lower_io_arrays_to_elements.c
+ *
+ * Split arrays/matrices with direct indexing into individual elements. This
+ * will allow optimisation passes to better clean up unused elements.
+ *
+ */
+
+static unsigned
+get_io_offset(nir_builder *b, nir_deref_var *deref, nir_variable *var,
+ unsigned *element_index)
+{
+ nir_deref *tail = &deref->deref;
+
+ /* For per-vertex input arrays (i.e. geometry shader inputs), skip the
+ * outermost array index. Process the rest normally.
+ */
+ if (nir_is_per_vertex_io(var, b->shader->info.stage)) {
+ tail = tail->child;
+ }
+
+ unsigned offset = 0;
+ while (tail->child != NULL) {
+ tail = tail->child;
+
+ if (tail->deref_type == nir_deref_type_array) {
+ nir_deref_array *deref_array = nir_deref_as_array(tail);
+ assert(deref_array->deref_array_type != nir_deref_array_type_indirect);
+
+ unsigned size = glsl_count_attribute_slots(tail->type, false);
+ offset += size * deref_array->base_offset;
+
+ unsigned num_elements = glsl_type_is_array(tail->type) ?
+ glsl_get_aoa_size(tail->type) : 1;
+
+ num_elements *= glsl_type_is_matrix(glsl_without_array(tail->type)) ?
+ glsl_get_matrix_columns(glsl_without_array(tail->type)) : 1;
+
+ *element_index += num_elements * deref_array->base_offset;
+ } else if (tail->deref_type == nir_deref_type_struct) {
+ /* TODO: we could also add struct splitting support to this pass */
+ break;
+ }
+ }
+
+ return offset;
+}
+
+static nir_variable **
+get_array_elements(struct hash_table *ht, nir_variable *var,
+ gl_shader_stage stage)
+{
+ nir_variable **elements;
+ struct hash_entry *entry = _mesa_hash_table_search(ht, var);
+ if (!entry) {
+ 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 num_elements = glsl_type_is_array(type) ?
+ glsl_get_aoa_size(type) : 1;
+
+ num_elements *= glsl_type_is_matrix(glsl_without_array(type)) ?
+ glsl_get_matrix_columns(glsl_without_array(type)) : 1;
+
+ elements = (nir_variable **) calloc(num_elements, sizeof(nir_variable *));
+ _mesa_hash_table_insert(ht, var, elements);
+ } else {
+ elements = (nir_variable **) entry->data;
+ }
+
+ return elements;
+}
+
+static void
+create_array_deref(nir_intrinsic_instr *arr_intr,
+ nir_intrinsic_instr *element_intr)
+{
+ assert(arr_intr->variables[0]->deref.child);
+
+ nir_deref *parent = &element_intr->variables[0]->deref;
+ nir_deref_array *darr =
+ nir_deref_as_array(arr_intr->variables[0]->deref.child);
+ nir_deref_array *ndarr = nir_deref_array_create(parent);
+
+ ndarr->deref.type = glsl_get_array_element(parent->type);
+ ndarr->deref_array_type = darr->deref_array_type;
+ ndarr->base_offset = darr->base_offset;
+
+ if (ndarr->deref_array_type == nir_deref_array_type_indirect)
+ nir_src_copy(&ndarr->indirect, &darr->indirect, parent);
+
+ element_intr->variables[0]->deref.child = &ndarr->deref;
+}
+
+static void
+lower_array(nir_builder *b, nir_intrinsic_instr *intr, nir_variable *var,
+ struct hash_table *varyings)
+{
+ b->cursor = nir_before_instr(&intr->instr);
+
+ nir_variable **elements =
+ get_array_elements(varyings, var, b->shader->info.stage);
+
+ unsigned elements_index = 0;
+ unsigned io_offset = get_io_offset(b, intr->variables[0], var,
+ &elements_index);
+
+ nir_variable *element = elements[elements_index];
+ if (!element) {
+ element = nir_variable_clone(var, b->shader);
+ element->data.location = var->data.location + io_offset;
+
+ const struct glsl_type *type = glsl_without_array(element->type);
+
+ /* This pass also splits matrices so we need give them a new type. */
+ if (glsl_type_is_matrix(type)) {
+ type = glsl_vector_type(glsl_get_base_type(type),
+ glsl_get_vector_elements(type));
+ }
+
+ if (nir_is_per_vertex_io(var, b->shader->info.stage)) {
+ type = glsl_get_array_instance(type,
+ glsl_get_length(element->type));
+ }
+
+ element->type = type;
+ elements[elements_index] = element;
+
+ nir_shader_add_variable(b->shader, element);
+ }
+
+ nir_intrinsic_instr *element_intr =
+ nir_intrinsic_instr_create(b->shader, intr->intrinsic);
+ element_intr->num_components = intr->num_components;
+ element_intr->variables[0] = nir_deref_var_create(element_intr, element);
+
+ if (intr->intrinsic != nir_intrinsic_store_var) {
+ nir_ssa_dest_init(&element_intr->instr, &element_intr->dest,
+ intr->num_components, intr->dest.ssa.bit_size, NULL);
+
+ if (intr->intrinsic == nir_intrinsic_interp_var_at_offset ||
+ intr->intrinsic == nir_intrinsic_interp_var_at_sample) {
+ nir_src_copy(&element_intr->src[0], &intr->src[0],
+ &element_intr->instr);
+ }
+
+ nir_ssa_def_rewrite_uses(&intr->dest.ssa,
+ nir_src_for_ssa(&element_intr->dest.ssa));
+ } else {
+ nir_intrinsic_set_write_mask(element_intr,
+ nir_intrinsic_write_mask(intr));
+ nir_src_copy(&element_intr->src[0], &intr->src[0],
+ &element_intr->instr);
+ }
+
+ if (nir_is_per_vertex_io(var, b->shader->info.stage)) {
+ create_array_deref(intr, element_intr);
+ }
+
+ nir_builder_instr_insert(b, &element_intr->instr);
+
+ /* Remove the old load intrinsic */
+ nir_instr_remove(&intr->instr);
+}
+
+static bool
+deref_has_indirect(nir_builder *b, nir_variable *var, nir_deref_var *deref)
+{
+ nir_deref *tail = &deref->deref;
+
+ if (nir_is_per_vertex_io(var, b->shader->info.stage)) {
+ tail = tail->child;
+ }
+
+ for (tail = tail->child; tail; tail = tail->child) {
+ if (tail->deref_type != nir_deref_type_array)
+ continue;
+
+ nir_deref_array *arr = nir_deref_as_array(tail);
+ if (arr->deref_array_type == nir_deref_array_type_indirect)
+ return true;
+ }
+
+ return false;
+}
+
+/* Creates a mask of locations that contains arrays that are indexed via
+ * indirect indexing.
+ */
+static void
+create_indirects_mask(nir_shader *shader, uint64_t *indirects,
+ uint64_t *patch_indirects, nir_variable_mode mode)
+{
+ nir_foreach_function(function, shader) {
+ if (function->impl) {
+ nir_builder b;
+ nir_builder_init(&b, function->impl);
+
+ nir_foreach_block(block, function->impl) {
+ nir_foreach_instr_safe(instr, block) {
+
+ if (instr->type != nir_instr_type_intrinsic)
+ continue;
+
+ nir_intrinsic_instr *intr = nir_instr_as_intrinsic(instr);
+
+ if (intr->intrinsic != nir_intrinsic_load_var &&
+ intr->intrinsic != nir_intrinsic_store_var &&
+ intr->intrinsic != nir_intrinsic_interp_var_at_centroid &&
+ intr->intrinsic != nir_intrinsic_interp_var_at_sample &&
+ intr->intrinsic != nir_intrinsic_interp_var_at_offset)
+ continue;
+
+ nir_variable *var = intr->variables[0]->var;
+
+ if (var->data.mode != mode)
+ continue;
+
+ uint64_t loc_mask = 1 << var->data.location;
+ if (var->data.patch) {
+ if (deref_has_indirect(&b, var, intr->variables[0]))
+ patch_indirects[var->data.location_frac] |= loc_mask;
+ } else {
+ if (deref_has_indirect(&b, var, intr->variables[0]))
+ indirects[var->data.location_frac] |= loc_mask;
+ }
+ }
+ }
+ }
+ }
+}
+
+static void
+lower_io_arrays_to_elements(nir_shader *shader, nir_variable_mode mask,
+ uint64_t *indirects, uint64_t *patch_indirects,
+ struct hash_table *varyings)
+{
+ nir_foreach_function(function, shader) {
+ if (function->impl) {
+ nir_builder b;
+ nir_builder_init(&b, function->impl);
+
+ nir_foreach_block(block, function->impl) {
+ nir_foreach_instr_safe(instr, block) {
+ if (instr->type != nir_instr_type_intrinsic)
+ continue;
+
+ nir_intrinsic_instr *intr = nir_instr_as_intrinsic(instr);
+
+ if (intr->intrinsic != nir_intrinsic_load_var &&
+ intr->intrinsic != nir_intrinsic_store_var &&
+ intr->intrinsic != nir_intrinsic_interp_var_at_centroid &&
+ intr->intrinsic != nir_intrinsic_interp_var_at_sample &&
+ intr->intrinsic != nir_intrinsic_interp_var_at_offset)
+ continue;
+
+ nir_variable *var = intr->variables[0]->var;
+
+ /* Skip indirects */
+ uint64_t loc_mask = 1 << var->data.location;
+ if (var->data.patch) {
+ if (patch_indirects[var->data.location_frac] & loc_mask)
+ continue;
+ } else {
+ if (indirects[var->data.location_frac] & loc_mask)
+ continue;
+ }
+
+ nir_variable_mode mode = var->data.mode;
+
+ const struct glsl_type *type = var->type;
+ if (nir_is_per_vertex_io(var, b.shader->info.stage)) {
+ assert(glsl_type_is_array(type));
+ type = glsl_get_array_element(type);
+ }
+
+ /* Skip types we cannot split.
+ *
+ * TODO: Add support for struct splitting.
+ */
+ if ((!glsl_type_is_array(type) && !glsl_type_is_matrix(type))||
+ glsl_type_is_struct(glsl_without_array(type)))
+ continue;
+
+ if (var->data.location < VARYING_SLOT_VAR0 &&
+ var->data.location >= 0)
+ continue;
+
+ /* Don't bother splitting if we can't opt away any unused
+ * elements.
+ */
+ if (var->data.always_active_io)
+ continue;
+
+ switch (intr->intrinsic) {
+ case nir_intrinsic_interp_var_at_centroid:
+ case nir_intrinsic_interp_var_at_sample:
+ case nir_intrinsic_interp_var_at_offset:
+ case nir_intrinsic_load_var:
+ case nir_intrinsic_store_var:
+ if ((mask & nir_var_shader_in && mode == nir_var_shader_in) ||
+ (mask & nir_var_shader_out && mode == nir_var_shader_out))
+ lower_array(&b, intr, var, varyings);
+ break;
+ default:
+ break;
+ }
+ }
+ }
+ }
+ }
+}
+
+void
+nir_lower_io_arrays_to_elements(nir_shader *producer, nir_shader *consumer)
+{
+ struct hash_table *split_inputs =
+ _mesa_hash_table_create(NULL, _mesa_hash_pointer,
+ _mesa_key_pointer_equal);
+ struct hash_table *split_outputs =
+ _mesa_hash_table_create(NULL, _mesa_hash_pointer,
+ _mesa_key_pointer_equal);
+
+ uint64_t indirects[4] = {0}, patch_indirects[4] = {0};
+ create_indirects_mask(producer, indirects, patch_indirects,
+ nir_var_shader_out);
+ create_indirects_mask(consumer, indirects, patch_indirects,
+ nir_var_shader_in);
+
+ lower_io_arrays_to_elements(producer, nir_var_shader_out, indirects,
+ patch_indirects, split_outputs);
+
+ lower_io_arrays_to_elements(consumer, nir_var_shader_in, indirects,
+ patch_indirects, split_inputs);
+
+ /* Remove old input from the shaders inputs list */
+ struct hash_entry *entry;
+ hash_table_foreach(split_inputs, entry) {
+ nir_variable *var = (nir_variable *) entry->key;
+ exec_node_remove(&var->node);
+
+ free(entry->data);
+ }
+
+ /* Remove old output from the shaders outputs list */
+ hash_table_foreach(split_outputs, entry) {
+ nir_variable *var = (nir_variable *) entry->key;
+ exec_node_remove(&var->node);
+
+ free(entry->data);
+ }
+
+ _mesa_hash_table_destroy(split_inputs, NULL);
+ _mesa_hash_table_destroy(split_outputs, NULL);
+}
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