--- /dev/null
+/*
+ * Copyright © 2014 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.
+ *
+ * Authors:
+ * Jason Ekstrand (jason@jlekstrand.net)
+ *
+ */
+
+#include "nir.h"
+
+struct deref_node {
+ struct deref_node *parent;
+ const struct glsl_type *type;
+
+ bool lower_to_ssa;
+
+ struct set *loads;
+ struct set *stores;
+ struct set *copies;
+
+ nir_ssa_def **def_stack;
+ nir_ssa_def **def_stack_tail;
+
+ struct deref_node *wildcard;
+ struct deref_node *indirect;
+ struct deref_node *children[0];
+};
+
+struct lower_variables_state {
+ void *mem_ctx;
+ void *dead_ctx;
+ nir_function_impl *impl;
+
+ /* A hash table mapping variables to deref_node data */
+ struct hash_table *deref_var_nodes;
+ /* A hash table mapping dereference leaves to deref_node data */
+ struct hash_table *deref_leaves;
+
+ /* A hash table mapping phi nodes to deref_state data */
+ struct hash_table *phi_table;
+};
+
+/* The following two functions implement a hash and equality check for
+ * variable dreferences. When the hash or equality function encounters an
+ * array, all indirects are treated as equal and are never equal to a
+ * direct dereference or a wildcard.
+ */
+static uint32_t
+hash_deref(const void *void_deref)
+{
+ const nir_deref *deref = void_deref;
+
+ uint32_t hash;
+ if (deref->child) {
+ hash = hash_deref(deref->child);
+ } else {
+ hash = 2166136261ul;
+ }
+
+ switch (deref->deref_type) {
+ case nir_deref_type_var:
+ hash ^= _mesa_hash_pointer(nir_deref_as_var(deref)->var);
+ break;
+ case nir_deref_type_array: {
+ nir_deref_array *array = nir_deref_as_array(deref);
+ hash += 268435183 * array->deref_array_type;
+ if (array->deref_array_type == nir_deref_array_type_direct)
+ hash ^= array->base_offset; /* Some prime */
+ break;
+ }
+ case nir_deref_type_struct:
+ hash ^= nir_deref_as_struct(deref)->index;
+ break;
+ }
+
+ return hash * 0x01000193;
+}
+
+static bool
+derefs_equal(const void *void_a, const void *void_b)
+{
+ const nir_deref *a = void_a;
+ const nir_deref *b = void_b;
+
+ if (a->deref_type != b->deref_type)
+ return false;
+
+ switch (a->deref_type) {
+ case nir_deref_type_var:
+ if (nir_deref_as_var(a)->var != nir_deref_as_var(b)->var)
+ return false;
+ break;
+ case nir_deref_type_array: {
+ nir_deref_array *a_arr = nir_deref_as_array(a);
+ nir_deref_array *b_arr = nir_deref_as_array(b);
+
+ if (a_arr->deref_array_type != b_arr->deref_array_type)
+ return false;
+
+ if (a_arr->deref_array_type == nir_deref_array_type_direct &&
+ a_arr->base_offset != b_arr->base_offset)
+ return false;
+ break;
+ }
+ case nir_deref_type_struct:
+ if (nir_deref_as_struct(a)->index != nir_deref_as_struct(b)->index)
+ return false;
+ break;
+ default:
+ unreachable("Invalid dreference type");
+ }
+
+ assert((a->child == NULL) == (b->child == NULL));
+ if (a->child)
+ return derefs_equal(a->child, b->child);
+ else
+ return true;
+}
+
+static int
+type_get_length(const struct glsl_type *type)
+{
+ switch (glsl_get_base_type(type)) {
+ case GLSL_TYPE_STRUCT:
+ case GLSL_TYPE_ARRAY:
+ return glsl_get_length(type);
+ case GLSL_TYPE_FLOAT:
+ case GLSL_TYPE_INT:
+ case GLSL_TYPE_UINT:
+ case GLSL_TYPE_BOOL:
+ if (glsl_type_is_matrix(type))
+ return glsl_get_matrix_columns(type);
+ else
+ return glsl_get_vector_elements(type);
+ default:
+ unreachable("Invalid deref base type");
+ }
+}
+
+static struct deref_node *
+deref_node_create(struct deref_node *parent,
+ const struct glsl_type *type, void *mem_ctx)
+{
+ size_t size = sizeof(struct deref_node) +
+ type_get_length(type) * sizeof(struct deref_node *);
+
+ struct deref_node *node = rzalloc_size(mem_ctx, size);
+ node->type = type;
+ node->parent = parent;
+
+ return node;
+}
+
+static struct deref_node *
+get_deref_node(nir_deref_var *deref, bool add_to_leaves,
+ struct lower_variables_state *state)
+{
+ bool is_leaf = true;
+ struct deref_node *parent = NULL;
+ nir_deref *tail = &deref->deref;
+ while (tail) {
+ struct deref_node *node;
+
+ switch (tail->deref_type) {
+ case nir_deref_type_var: {
+ assert(tail == &deref->deref);
+ assert(parent == NULL);
+
+ struct hash_entry *entry =
+ _mesa_hash_table_search(state->deref_var_nodes, deref->var);
+ if (entry) {
+ node = entry->data;
+ } else {
+ node = deref_node_create(NULL, tail->type, state->dead_ctx);
+ _mesa_hash_table_insert(state->deref_var_nodes, deref->var, node);
+ }
+ break;
+ }
+
+ case nir_deref_type_struct: {
+ assert(parent != NULL);
+
+ nir_deref_struct *deref_struct = nir_deref_as_struct(tail);
+ assert(deref_struct->index < type_get_length(parent->type));
+ if (parent->children[deref_struct->index]) {
+ node = parent->children[deref_struct->index];
+ } else {
+ node = deref_node_create(parent, tail->type, state->dead_ctx);
+ parent->children[deref_struct->index] = node;
+ }
+ break;
+ }
+
+ case nir_deref_type_array: {
+ assert(parent != NULL);
+
+ nir_deref_array *arr = nir_deref_as_array(tail);
+ switch (arr->deref_array_type) {
+ case nir_deref_array_type_direct:
+ if (arr->base_offset >= type_get_length(parent->type)) {
+ /* This is possible if a loop unrolls and generates an
+ * out-of-bounds offset. We need to handle this at least
+ * somewhat gracefully.
+ */
+ return NULL;
+ } else if (parent->children[arr->base_offset]) {
+ node = parent->children[arr->base_offset];
+ } else {
+ node = deref_node_create(parent, tail->type, state->dead_ctx);
+ parent->children[arr->base_offset] = node;
+ }
+ break;
+ case nir_deref_array_type_indirect:
+ if (parent->indirect) {
+ node = parent->indirect;
+ } else {
+ node = deref_node_create(parent, tail->type, state->dead_ctx);
+ parent->indirect = node;
+ }
+ is_leaf = false;
+ break;
+ case nir_deref_array_type_wildcard:
+ if (parent->wildcard) {
+ node = parent->wildcard;
+ } else {
+ node = deref_node_create(parent, tail->type, state->dead_ctx);
+ parent->wildcard = node;
+ }
+ is_leaf = false;
+ break;
+ default:
+ unreachable("Invalid array deref type");
+ }
+ break;
+ }
+ default:
+ unreachable("Invalid deref type");
+ }
+
+ parent = node;
+ tail = tail->child;
+ }
+
+ assert(parent);
+
+ if (is_leaf && add_to_leaves)
+ _mesa_hash_table_insert(state->deref_leaves, deref, parent);
+
+ return parent;
+}
+
+static void
+register_load_instr(nir_intrinsic_instr *load_instr, bool create_node,
+ struct lower_variables_state *state)
+{
+ struct deref_node *node = get_deref_node(load_instr->variables[0],
+ create_node, state);
+ if (node == NULL)
+ return;
+
+ if (node->loads == NULL)
+ node->loads = _mesa_set_create(state->dead_ctx,
+ _mesa_key_pointer_equal);
+
+ _mesa_set_add(node->loads, _mesa_hash_pointer(load_instr), load_instr);
+}
+
+static void
+register_store_instr(nir_intrinsic_instr *store_instr, bool create_node,
+ struct lower_variables_state *state)
+{
+ struct deref_node *node = get_deref_node(store_instr->variables[0],
+ create_node, state);
+ if (node == NULL)
+ return;
+
+ if (node->stores == NULL)
+ node->stores = _mesa_set_create(state->dead_ctx,
+ _mesa_key_pointer_equal);
+
+ _mesa_set_add(node->stores, _mesa_hash_pointer(store_instr), store_instr);
+}
+
+static void
+register_copy_instr(nir_intrinsic_instr *copy_instr, bool create_node,
+ struct lower_variables_state *state)
+{
+ for (unsigned idx = 0; idx < 2; idx++) {
+ struct deref_node *node = get_deref_node(copy_instr->variables[idx],
+ create_node, state);
+ if (node == NULL)
+ continue;
+
+ if (node->copies == NULL)
+ node->copies = _mesa_set_create(state->dead_ctx,
+ _mesa_key_pointer_equal);
+
+ _mesa_set_add(node->copies, _mesa_hash_pointer(copy_instr), copy_instr);
+ }
+}
+
+static bool
+foreach_deref_node_worker(struct deref_node *node, nir_deref *deref,
+ bool (* cb)(struct deref_node *node,
+ struct lower_variables_state *state),
+ struct lower_variables_state *state)
+{
+ if (deref->child == NULL) {
+ return cb(node, state);
+ } else {
+ switch (deref->child->deref_type) {
+ case nir_deref_type_array: {
+ nir_deref_array *arr = nir_deref_as_array(deref->child);
+ assert(arr->deref_array_type == nir_deref_array_type_direct);
+ if (node->children[arr->base_offset] &&
+ !foreach_deref_node_worker(node->children[arr->base_offset],
+ deref->child, cb, state))
+ return false;
+
+ if (node->wildcard &&
+ !foreach_deref_node_worker(node->wildcard,
+ deref->child, cb, state))
+ return false;
+
+ return true;
+ }
+
+ case nir_deref_type_struct: {
+ nir_deref_struct *str = nir_deref_as_struct(deref->child);
+ return foreach_deref_node_worker(node->children[str->index],
+ deref->child, cb, state);
+ }
+
+ default:
+ unreachable("Invalid deref child type");
+ }
+ }
+}
+
+static bool
+foreach_deref_node_match(nir_deref_var *deref,
+ bool (* cb)(struct deref_node *node,
+ struct lower_variables_state *state),
+ struct lower_variables_state *state)
+{
+ nir_deref_var var_deref = *deref;
+ var_deref.deref.child = NULL;
+ struct deref_node *node = get_deref_node(&var_deref, false, state);
+
+ if (node == NULL)
+ return false;
+
+ return foreach_deref_node_worker(node, &deref->deref, cb, state);
+}
+
+/* This question can only be asked about leaves. Searching down the tree
+ * is much harder than searching up.
+ */
+static bool
+deref_may_be_aliased_node(struct deref_node *node, nir_deref *deref,
+ struct lower_variables_state *state)
+{
+ if (deref->child == NULL) {
+ return false;
+ } else {
+ switch (deref->child->deref_type) {
+ case nir_deref_type_array: {
+ nir_deref_array *arr = nir_deref_as_array(deref->child);
+ if (arr->deref_array_type == nir_deref_array_type_indirect)
+ return true;
+
+ assert(arr->deref_array_type == nir_deref_array_type_direct);
+
+ if (node->children[arr->base_offset] &&
+ deref_may_be_aliased_node(node->children[arr->base_offset],
+ deref->child, state))
+ return true;
+
+ if (node->wildcard &&
+ deref_may_be_aliased_node(node->wildcard, deref->child, state))
+ return true;
+
+ return false;
+ }
+
+ case nir_deref_type_struct: {
+ nir_deref_struct *str = nir_deref_as_struct(deref->child);
+ if (node->children[str->index]) {
+ return deref_may_be_aliased_node(node->children[str->index],
+ deref->child, state);
+ } else {
+ return false;
+ }
+ }
+
+ default:
+ unreachable("Invalid nir_deref child type");
+ }
+ }
+}
+
+static bool
+deref_may_be_aliased(nir_deref_var *deref,
+ struct lower_variables_state *state)
+{
+ nir_deref_var var_deref = *deref;
+ var_deref.deref.child = NULL;
+ struct deref_node *node = get_deref_node(&var_deref, false, state);
+
+ /* An invalid dereference can't be aliased. */
+ if (node == NULL)
+ return false;
+
+ return deref_may_be_aliased_node(node, &deref->deref, state);
+}
+
+static bool
+fill_deref_tables_block(nir_block *block, void *void_state)
+{
+ struct lower_variables_state *state = void_state;
+
+ nir_foreach_instr_safe(block, instr) {
+ if (instr->type != nir_instr_type_intrinsic)
+ continue;
+
+ nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr);
+
+ switch (intrin->intrinsic) {
+ case nir_intrinsic_load_var_vec1:
+ case nir_intrinsic_load_var_vec2:
+ case nir_intrinsic_load_var_vec3:
+ case nir_intrinsic_load_var_vec4:
+ register_load_instr(intrin, true, state);
+ break;
+
+ case nir_intrinsic_store_var_vec1:
+ case nir_intrinsic_store_var_vec2:
+ case nir_intrinsic_store_var_vec3:
+ case nir_intrinsic_store_var_vec4:
+ register_store_instr(intrin, true, state);
+ break;
+
+ case nir_intrinsic_copy_var:
+ register_copy_instr(intrin, true, state);
+ break;
+
+ default:
+ continue;
+ }
+ }
+
+ return true;
+}
+
+static nir_deref *
+deref_next_wildcard_parent(nir_deref *deref)
+{
+ for (nir_deref *tail = deref; tail->child; tail = tail->child) {
+ if (tail->child->deref_type != nir_deref_type_array)
+ continue;
+
+ nir_deref_array *arr = nir_deref_as_array(tail->child);
+
+ if (arr->deref_array_type == nir_deref_array_type_wildcard)
+ return tail;
+ }
+
+ return NULL;
+}
+
+static nir_deref *
+get_deref_tail(nir_deref *deref)
+{
+ while (deref->child)
+ deref = deref->child;
+
+ return deref;
+}
+
+static void
+emit_copy_load_store(nir_intrinsic_instr *copy_instr,
+ nir_deref_var *dest_head, nir_deref_var *src_head,
+ nir_deref *dest_tail, nir_deref *src_tail,
+ struct lower_variables_state *state)
+{
+ nir_deref *src_arr_parent = deref_next_wildcard_parent(src_tail);
+ nir_deref *dest_arr_parent = deref_next_wildcard_parent(dest_tail);
+
+ if (src_arr_parent || dest_arr_parent) {
+ assert(dest_arr_parent && dest_arr_parent);
+
+ nir_deref_array *src_arr = nir_deref_as_array(src_arr_parent->child);
+ nir_deref_array *dest_arr = nir_deref_as_array(dest_arr_parent->child);
+
+ unsigned length = type_get_length(src_arr_parent->type);
+ assert(length == type_get_length(dest_arr_parent->type));
+ assert(length > 0);
+
+ src_arr->deref_array_type = nir_deref_array_type_direct;
+ dest_arr->deref_array_type = nir_deref_array_type_direct;
+ for (unsigned i = 0; i < length; i++) {
+ src_arr->base_offset = i;
+ dest_arr->base_offset = i;
+ emit_copy_load_store(copy_instr, dest_head, src_head,
+ &dest_arr->deref, &src_arr->deref, state);
+ }
+ src_arr->deref_array_type = nir_deref_array_type_wildcard;
+ dest_arr->deref_array_type = nir_deref_array_type_wildcard;
+ } else {
+ /* Base case. Actually do the copy */
+ src_tail = get_deref_tail(src_tail);
+ dest_tail = get_deref_tail(dest_tail);
+
+ assert(src_tail->type == dest_tail->type);
+
+ unsigned num_components = glsl_get_vector_elements(src_tail->type);
+
+ nir_deref *src_deref = nir_copy_deref(state->mem_ctx, &src_head->deref);
+ nir_deref *dest_deref = nir_copy_deref(state->mem_ctx, &dest_head->deref);
+
+ nir_intrinsic_op load_op;
+ switch (num_components) {
+ case 1: load_op = nir_intrinsic_load_var_vec1; break;
+ case 2: load_op = nir_intrinsic_load_var_vec2; break;
+ case 3: load_op = nir_intrinsic_load_var_vec3; break;
+ case 4: load_op = nir_intrinsic_load_var_vec4; break;
+ default: unreachable("Invalid number of components"); break;
+ }
+
+ nir_intrinsic_instr *load = nir_intrinsic_instr_create(state->mem_ctx,
+ load_op);
+ load->variables[0] = nir_deref_as_var(src_deref);
+ load->dest.is_ssa = true;
+ nir_ssa_def_init(&load->instr, &load->dest.ssa, num_components, NULL);
+
+ nir_instr_insert_before(©_instr->instr, &load->instr);
+ register_load_instr(load, false, state);
+
+ nir_intrinsic_op store_op;
+ switch (num_components) {
+ case 1: store_op = nir_intrinsic_store_var_vec1; break;
+ case 2: store_op = nir_intrinsic_store_var_vec2; break;
+ case 3: store_op = nir_intrinsic_store_var_vec3; break;
+ case 4: store_op = nir_intrinsic_store_var_vec4; break;
+ default: unreachable("Invalid number of components"); break;
+ }
+
+ nir_intrinsic_instr *store = nir_intrinsic_instr_create(state->mem_ctx,
+ store_op);
+ store->variables[0] = nir_deref_as_var(dest_deref);
+ store->src[0].is_ssa = true;
+ store->src[0].ssa = &load->dest.ssa;
+
+ if (copy_instr->has_predicate) {
+ store->has_predicate = true;
+ store->predicate = nir_src_copy(copy_instr->predicate, state->mem_ctx);
+ }
+
+ nir_instr_insert_before(©_instr->instr, &store->instr);
+ register_store_instr(store, false, state);
+ }
+}
+
+static bool
+lower_copies_to_load_store(struct deref_node *node,
+ struct lower_variables_state *state)
+{
+ if (!node->copies)
+ return true;
+
+ struct set_entry *copy_entry;
+ set_foreach(node->copies, copy_entry) {
+ nir_intrinsic_instr *copy = (void *)copy_entry->key;
+
+ emit_copy_load_store(copy, copy->variables[0], copy->variables[1],
+ ©->variables[0]->deref,
+ ©->variables[1]->deref,
+ state);
+
+ for (unsigned i = 0; i < 2; ++i) {
+ struct deref_node *arg_node = get_deref_node(copy->variables[i],
+ false, state);
+ if (arg_node == NULL)
+ continue;
+
+ struct set_entry *arg_entry = _mesa_set_search(arg_node->copies,
+ copy_entry->hash,
+ copy);
+ assert(arg_entry);
+ _mesa_set_remove(node->copies, arg_entry);
+ }
+
+ nir_instr_remove(©->instr);
+ }
+
+ return true;
+}
+
+static nir_load_const_instr *
+get_const_initializer_load(const nir_deref_var *deref,
+ struct lower_variables_state *state)
+{
+ nir_constant *constant = deref->var->constant_initializer;
+ const nir_deref *tail = &deref->deref;
+ unsigned matrix_offset = 0;
+ while (tail->child) {
+ switch (tail->child->deref_type) {
+ case nir_deref_type_array: {
+ nir_deref_array *arr = nir_deref_as_array(tail->child);
+ assert(arr->deref_array_type == nir_deref_array_type_direct);
+ if (glsl_type_is_matrix(tail->type)) {
+ assert(arr->deref.child == NULL);
+ matrix_offset = arr->base_offset;
+ } else {
+ constant = constant->elements[arr->base_offset];
+ }
+ break;
+ }
+
+ case nir_deref_type_struct: {
+ constant = constant->elements[nir_deref_as_struct(tail->child)->index];
+ break;
+ }
+
+ default:
+ unreachable("Invalid deref child type");
+ }
+
+ tail = tail->child;
+ }
+
+ nir_load_const_instr *load = nir_load_const_instr_create(state->mem_ctx);
+ load->array_elems = 0;
+ load->num_components = glsl_get_vector_elements(tail->type);
+
+ matrix_offset *= load->num_components;
+ for (unsigned i = 0; i < load->num_components; i++) {
+ switch (glsl_get_base_type(tail->type)) {
+ case GLSL_TYPE_FLOAT:
+ case GLSL_TYPE_INT:
+ case GLSL_TYPE_UINT:
+ load->value.u[i] = constant->value.u[matrix_offset + i];
+ break;
+ case GLSL_TYPE_BOOL:
+ load->value.u[i] = constant->value.u[matrix_offset + i] ?
+ NIR_TRUE : NIR_FALSE;
+ break;
+ default:
+ unreachable("Invalid immediate type");
+ }
+ }
+
+ return load;
+}
+
+static void
+def_stack_push(struct deref_node *node, nir_ssa_def *def,
+ struct lower_variables_state *state)
+{
+ if (node->def_stack == NULL) {
+ node->def_stack = ralloc_array(state->dead_ctx, nir_ssa_def *,
+ state->impl->num_blocks);
+ node->def_stack_tail = node->def_stack - 1;
+ }
+
+ if (node->def_stack_tail >= node->def_stack) {
+ nir_ssa_def *top_def = *node->def_stack_tail;
+
+ if (def->parent_instr->block == top_def->parent_instr->block) {
+ /* They're in the same block, just replace the top */
+ *node->def_stack_tail = def;
+ return;
+ }
+ }
+
+ *(++node->def_stack_tail) = def;
+}
+
+static nir_ssa_def *
+get_ssa_def_for_block(struct deref_node *node, nir_block *block,
+ struct lower_variables_state *state)
+{
+ if (node->def_stack) {
+ while (node->def_stack_tail >= node->def_stack) {
+ nir_ssa_def *def = *node->def_stack_tail;
+
+ for (nir_block *dom = block; dom != NULL; dom = dom->imm_dom) {
+ if (def->parent_instr->block == dom)
+ return def;
+ }
+
+ node->def_stack_tail--;
+ }
+ }
+
+ /* If we got here then we don't have a definition that dominates the
+ * given block. This means that we need to add an undef and use that.
+ */
+ nir_ssa_undef_instr *undef = nir_ssa_undef_instr_create(state->mem_ctx);
+ nir_ssa_def_init(&undef->instr, &undef->def,
+ glsl_get_vector_elements(node->type), NULL);
+ nir_instr_insert_before_cf_list(&state->impl->body, &undef->instr);
+ def_stack_push(node, &undef->def, state);
+ return &undef->def;
+}
+
+static void
+add_phi_sources(nir_block *block, nir_block *pred,
+ struct lower_variables_state *state)
+{
+ nir_foreach_instr(block, instr) {
+ if (instr->type != nir_instr_type_phi)
+ break;
+
+ nir_phi_instr *phi = nir_instr_as_phi(instr);
+
+ struct hash_entry *entry =
+ _mesa_hash_table_search(state->phi_table, phi);
+ if (!entry)
+ continue;
+
+ struct deref_node *node = entry->data;
+
+ nir_phi_src *src = ralloc(state->mem_ctx, nir_phi_src);
+ src->pred = pred;
+ src->src.is_ssa = true;
+ src->src.ssa = get_ssa_def_for_block(node, pred, state);
+
+ _mesa_set_add(src->src.ssa->uses, _mesa_hash_pointer(instr), instr);
+
+ exec_list_push_tail(&phi->srcs, &src->node);
+ }
+}
+
+static bool
+lower_deref_to_ssa_block(nir_block *block, void *void_state)
+{
+ struct lower_variables_state *state = void_state;
+
+ nir_foreach_instr_safe(block, instr) {
+ if (instr->type == nir_instr_type_phi) {
+ nir_phi_instr *phi = nir_instr_as_phi(instr);
+
+ struct hash_entry *entry =
+ _mesa_hash_table_search(state->phi_table, phi);
+
+ /* This can happen if we already have phi nodes in the program
+ * that were not created in this pass.
+ */
+ if (!entry)
+ continue;
+
+ struct deref_node *node = entry->data;
+
+ def_stack_push(node, &phi->dest.ssa, state);
+ } else if (instr->type == nir_instr_type_intrinsic) {
+ nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr);
+
+ switch (intrin->intrinsic) {
+ case nir_intrinsic_load_var_vec1:
+ case nir_intrinsic_load_var_vec2:
+ case nir_intrinsic_load_var_vec3:
+ case nir_intrinsic_load_var_vec4: {
+ struct deref_node *node = get_deref_node(intrin->variables[0],
+ false, state);
+ unsigned num_chans =
+ nir_intrinsic_infos[intrin->intrinsic].dest_components;
+
+ if (node == NULL) {
+ /* If we hit this path then we are referencing an invalid
+ * value. Most likely, we unrolled something and are
+ * reading past the end of some array. In any case, this
+ * should result in an undefined value.
+ */
+ nir_ssa_undef_instr *undef =
+ nir_ssa_undef_instr_create(state->mem_ctx);
+ nir_ssa_def_init(&undef->instr, &undef->def, num_chans, NULL);
+
+ nir_instr_insert_before(&intrin->instr, &undef->instr);
+ nir_instr_remove(&intrin->instr);
+
+ nir_src new_src = {
+ .is_ssa = true,
+ .ssa = &undef->def,
+ };
+
+ nir_ssa_def_rewrite_uses(&intrin->dest.ssa, new_src,
+ state->mem_ctx);
+ continue;
+ }
+
+ if (!node->lower_to_ssa)
+ continue;
+
+ nir_alu_instr *mov = nir_alu_instr_create(state->mem_ctx,
+ nir_op_imov);
+ mov->src[0].src.is_ssa = true;
+ mov->src[0].src.ssa = get_ssa_def_for_block(node, block, state);
+ for (unsigned i = num_chans; i < 4; i++)
+ mov->src[0].swizzle[i] = 0;
+
+ assert(intrin->dest.is_ssa);
+
+ mov->dest.write_mask = (1 << num_chans) - 1;
+ mov->dest.dest.is_ssa = true;
+ nir_ssa_def_init(&mov->instr, &mov->dest.dest.ssa, num_chans, NULL);
+
+ nir_instr_insert_before(&intrin->instr, &mov->instr);
+ nir_instr_remove(&intrin->instr);
+
+ nir_src new_src = {
+ .is_ssa = true,
+ .ssa = &mov->dest.dest.ssa,
+ };
+
+ nir_ssa_def_rewrite_uses(&intrin->dest.ssa, new_src,
+ state->mem_ctx);
+ break;
+ }
+
+ case nir_intrinsic_store_var_vec1:
+ case nir_intrinsic_store_var_vec2:
+ case nir_intrinsic_store_var_vec3:
+ case nir_intrinsic_store_var_vec4: {
+ struct deref_node *node = get_deref_node(intrin->variables[0],
+ false, state);
+
+ if (node == NULL) {
+ /* Probably an out-of-bounds array store. That should be a
+ * no-op. */
+ nir_instr_remove(&intrin->instr);
+ continue;
+ }
+
+ if (!node->lower_to_ssa)
+ continue;
+
+ unsigned num_chans = glsl_get_vector_elements(node->type);
+
+ assert(intrin->src[0].is_ssa);
+
+ nir_alu_instr *mov;
+ if (intrin->has_predicate) {
+ mov = nir_alu_instr_create(state->mem_ctx, nir_op_bcsel);
+ mov->src[0].src = nir_src_copy(intrin->predicate,
+ state->mem_ctx);
+ memset(mov->src[0].swizzle, 0, sizeof mov->src[0].swizzle);
+
+ mov->src[1].src.is_ssa = true;
+ mov->src[1].src.ssa = intrin->src[0].ssa;
+ for (unsigned i = num_chans; i < 4; i++)
+ mov->src[1].swizzle[i] = 0;
+
+ mov->src[2].src.is_ssa = true;
+ mov->src[2].src.ssa = get_ssa_def_for_block(node, block, state);
+ for (unsigned i = num_chans; i < 4; i++)
+ mov->src[2].swizzle[i] = 0;
+
+ } else {
+ mov = nir_alu_instr_create(state->mem_ctx, nir_op_imov);
+
+ mov->src[0].src.is_ssa = true;
+ mov->src[0].src.ssa = intrin->src[0].ssa;
+ for (unsigned i = num_chans; i < 4; i++)
+ mov->src[0].swizzle[i] = 0;
+ }
+
+ mov->dest.write_mask = (1 << num_chans) - 1;
+ mov->dest.dest.is_ssa = true;
+ nir_ssa_def_init(&mov->instr, &mov->dest.dest.ssa, num_chans, NULL);
+
+ nir_instr_insert_before(&intrin->instr, &mov->instr);
+ nir_instr_remove(&intrin->instr);
+
+ def_stack_push(node, &mov->dest.dest.ssa, state);
+ break;
+ }
+
+ default:
+ break;
+ }
+ }
+ }
+
+ if (block->successors[0])
+ add_phi_sources(block->successors[0], block, state);
+ if (block->successors[1])
+ add_phi_sources(block->successors[1], block, state);
+
+ return true;
+}
+
+static void
+insert_phi_nodes(struct lower_variables_state *state)
+{
+ unsigned work[state->impl->num_blocks];
+ unsigned has_already[state->impl->num_blocks];
+ nir_block *W[state->impl->num_blocks];
+
+ memset(work, 0, sizeof work);
+ memset(has_already, 0, sizeof has_already);
+
+ unsigned w_start, w_end;
+ unsigned iter_count = 0;
+
+ struct hash_entry *deref_entry;
+ hash_table_foreach(state->deref_leaves, deref_entry) {
+ struct deref_node *node = deref_entry->data;
+
+ if (node->stores == NULL)
+ continue;
+
+ if (!node->lower_to_ssa)
+ continue;
+
+ w_start = w_end = 0;
+ iter_count++;
+
+ struct set_entry *store_entry;
+ set_foreach(node->stores, store_entry) {
+ nir_intrinsic_instr *store = (nir_intrinsic_instr *)store_entry->key;
+ if (work[store->instr.block->index] < iter_count)
+ W[w_end++] = store->instr.block;
+ work[store->instr.block->index] = iter_count;
+ }
+
+ while (w_start != w_end) {
+ nir_block *cur = W[w_start++];
+ struct set_entry *dom_entry;
+ set_foreach(cur->dom_frontier, dom_entry) {
+ nir_block *next = (nir_block *) dom_entry->key;
+
+ /*
+ * If there's more than one return statement, then the end block
+ * can be a join point for some definitions. However, there are
+ * no instructions in the end block, so nothing would use those
+ * phi nodes. Of course, we couldn't place those phi nodes
+ * anyways due to the restriction of having no instructions in the
+ * end block...
+ */
+ if (next == state->impl->end_block)
+ continue;
+
+ if (has_already[next->index] < iter_count) {
+ nir_phi_instr *phi = nir_phi_instr_create(state->mem_ctx);
+ phi->dest.is_ssa = true;
+ nir_ssa_def_init(&phi->instr, &phi->dest.ssa,
+ glsl_get_vector_elements(node->type), NULL);
+ nir_instr_insert_before_block(next, &phi->instr);
+
+ _mesa_hash_table_insert(state->phi_table, phi, node);
+
+ has_already[next->index] = iter_count;
+ if (work[next->index] < iter_count) {
+ work[next->index] = iter_count;
+ W[w_end++] = next;
+ }
+ }
+ }
+ }
+ }
+}
+
+static bool
+nir_lower_variables_impl(nir_function_impl *impl)
+{
+ struct lower_variables_state state;
+
+ state.mem_ctx = ralloc_parent(impl);
+ state.dead_ctx = ralloc_context(state.mem_ctx);
+ state.impl = impl;
+
+ state.deref_var_nodes = _mesa_hash_table_create(state.dead_ctx,
+ _mesa_hash_pointer,
+ _mesa_key_pointer_equal);
+ state.deref_leaves = _mesa_hash_table_create(state.dead_ctx,
+ hash_deref, derefs_equal);
+ state.phi_table = _mesa_hash_table_create(state.dead_ctx,
+ _mesa_hash_pointer,
+ _mesa_key_pointer_equal);
+
+ nir_foreach_block(impl, fill_deref_tables_block, &state);
+
+ struct set *outputs = _mesa_set_create(state.dead_ctx,
+ _mesa_key_pointer_equal);
+
+ bool progress = false;
+
+ nir_metadata_require(impl, nir_metadata_block_index);
+
+ struct hash_entry *entry;
+ hash_table_foreach(state.deref_leaves, entry) {
+ nir_deref_var *deref = (void *)entry->key;
+ struct deref_node *node = entry->data;
+
+ if (deref->var->data.mode != nir_var_local) {
+ _mesa_hash_table_remove(state.deref_leaves, entry);
+ continue;
+ }
+
+ if (deref_may_be_aliased(deref, &state)) {
+ _mesa_hash_table_remove(state.deref_leaves, entry);
+ continue;
+ }
+
+ node->lower_to_ssa = true;
+ progress = true;
+
+ if (deref->var->constant_initializer) {
+ nir_load_const_instr *load = get_const_initializer_load(deref, &state);
+ load->dest.is_ssa = true;
+ nir_ssa_def_init(&load->instr, &load->dest.ssa,
+ glsl_get_vector_elements(node->type), NULL);
+ nir_instr_insert_before_cf_list(&impl->body, &load->instr);
+ def_stack_push(node, &load->dest.ssa, &state);
+ }
+
+ if (deref->var->data.mode == nir_var_shader_out)
+ _mesa_set_add(outputs, _mesa_hash_pointer(node), node);
+
+ foreach_deref_node_match(deref, lower_copies_to_load_store, &state);
+ }
+
+ if (!progress)
+ return false;
+
+ nir_metadata_require(impl, nir_metadata_dominance);
+
+ insert_phi_nodes(&state);
+ nir_foreach_block(impl, lower_deref_to_ssa_block, &state);
+
+ nir_metadata_dirty(impl, nir_metadata_block_index |
+ nir_metadata_dominance);
+
+ ralloc_free(state.dead_ctx);
+
+ return progress;
+}
+
+void
+nir_lower_variables(nir_shader *shader)
+{
+ nir_foreach_overload(shader, overload) {
+ if (overload->impl)
+ nir_lower_variables_impl(overload->impl);
+ }
+}
projects / mesa.git / commitdiff