--- /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 locals_to_regs_state {
+ void *mem_ctx;
+ nir_function_impl *impl;
+
+ /* A hash table mapping derefs to registers */
+ struct hash_table *regs_table;
+};
+
+/* The following two functions implement a hash and equality check for
+ * variable dreferences. When the hash or equality function encounters an
+ * array, it ignores the offset and whether it is direct or indirect
+ * entirely.
+ */
+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: {
+ hash ^= 268435183;
+ 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:
+ /* Do nothing. All array derefs are the same */
+ 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 nir_register *
+get_reg_for_deref(nir_deref_var *deref, struct locals_to_regs_state *state)
+{
+ uint32_t hash = hash_deref(deref);
+
+ struct hash_entry *entry =
+ _mesa_hash_table_search_pre_hashed(state->regs_table, hash, deref);
+ if (entry)
+ return entry->data;
+
+ unsigned array_size = 1;
+ nir_deref *tail = &deref->deref;
+ while (tail->child) {
+ if (tail->child->deref_type == nir_deref_type_array) {
+ /* Multiply by the parent's type. */
+ if (glsl_type_is_matrix(tail->type)) {
+ array_size *= glsl_get_matrix_columns(tail->type);
+ } else {
+ assert(glsl_get_length(tail->type) > 0);
+ array_size *= glsl_get_length(tail->type);
+ }
+ }
+ tail = tail->child;
+ }
+
+ assert(glsl_type_is_vector(tail->type) || glsl_type_is_scalar(tail->type));
+
+ nir_register *reg = nir_local_reg_create(state->impl);
+ reg->num_components = glsl_get_vector_elements(tail->type);
+ reg->num_array_elems = array_size > 1 ? array_size : 0;
+
+ _mesa_hash_table_insert_with_hash(state->regs_table, hash, deref, reg);
+
+ return reg;
+}
+
+static nir_src
+get_deref_reg_src(nir_deref_var *deref, nir_instr *instr,
+ struct locals_to_regs_state *state)
+{
+ nir_src src;
+
+ src.is_ssa = false;
+ src.reg.reg = get_reg_for_deref(deref, state);
+ src.reg.base_offset = 0;
+ src.reg.indirect = NULL;
+
+ nir_deref *tail = &deref->deref;
+ while (tail->child != NULL) {
+ const struct glsl_type *parent_type = tail->type;
+ tail = tail->child;
+
+ if (tail->deref_type != nir_deref_type_array)
+ continue;
+
+ nir_deref_array *deref_array = nir_deref_as_array(tail);
+
+ src.reg.base_offset *= glsl_get_length(parent_type);
+ src.reg.base_offset += deref_array->base_offset;
+
+ if (src.reg.indirect) {
+ nir_load_const_instr *load_const =
+ nir_load_const_instr_create(state->mem_ctx);
+ load_const->num_components = 1;
+ load_const->value.u[0] = glsl_get_length(parent_type);
+ load_const->dest.is_ssa = true;
+ nir_ssa_def_init(&load_const->instr, &load_const->dest.ssa, 1, NULL);
+ nir_instr_insert_before(instr, &load_const->instr);
+
+ nir_alu_instr *mul = nir_alu_instr_create(state->mem_ctx, nir_op_imul);
+ mul->src[0].src = *src.reg.indirect;
+ mul->src[1].src.is_ssa = true;
+ mul->src[1].src.ssa = &load_const->dest.ssa;
+ mul->dest.write_mask = 1;
+ mul->dest.dest.is_ssa = true;
+ nir_ssa_def_init(&mul->instr, &mul->dest.dest.ssa, 1, NULL);
+ nir_instr_insert_before(instr, &mul->instr);
+
+ src.reg.indirect->is_ssa = true;
+ src.reg.indirect->ssa = &mul->dest.dest.ssa;
+ }
+
+ if (deref_array->deref_array_type == nir_deref_array_type_indirect) {
+ if (src.reg.indirect == NULL) {
+ src.reg.indirect = ralloc(state->mem_ctx, nir_src);
+ *src.reg.indirect = nir_src_copy(deref_array->indirect,
+ state->mem_ctx);
+ } else {
+ nir_alu_instr *add = nir_alu_instr_create(state->mem_ctx,
+ nir_op_iadd);
+ add->src[0].src = *src.reg.indirect;
+ add->src[1].src = nir_src_copy(deref_array->indirect,
+ state->mem_ctx);
+ add->dest.write_mask = 1;
+ add->dest.dest.is_ssa = true;
+ nir_ssa_def_init(&add->instr, &add->dest.dest.ssa, 1, NULL);
+ nir_instr_insert_before(instr, &add->instr);
+
+ src.reg.indirect->is_ssa = true;
+ src.reg.indirect->ssa = &add->dest.dest.ssa;
+ }
+ }
+ }
+
+ return src;
+}
+
+static bool
+lower_locals_to_regs_block(nir_block *block, void *void_state)
+{
+ struct locals_to_regs_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: {
+ if (intrin->variables[0]->var->data.mode != nir_var_local)
+ continue;
+
+ nir_alu_instr *mov = nir_alu_instr_create(state->mem_ctx, nir_op_imov);
+ mov->src[0].src = get_deref_reg_src(intrin->variables[0],
+ &intrin->instr, state);
+ unsigned num_components = mov->src[0].src.reg.reg->num_components;
+ mov->dest.write_mask = (1 << num_components) - 1;
+ if (intrin->dest.is_ssa) {
+ mov->dest.dest.is_ssa = true;
+ nir_ssa_def_init(&mov->instr, &mov->dest.dest.ssa,
+ num_components, NULL);
+
+ 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);
+ } else {
+ mov->dest.dest = nir_dest_copy(intrin->dest, state->mem_ctx);
+ }
+ nir_instr_insert_before(&intrin->instr, &mov->instr);
+
+ nir_instr_remove(&intrin->instr);
+ 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: {
+ if (intrin->variables[0]->var->data.mode != nir_var_local)
+ continue;
+
+ nir_src reg_src = get_deref_reg_src(intrin->variables[0],
+ &intrin->instr, state);
+ unsigned num_components = reg_src.reg.reg->num_components;
+
+ nir_alu_instr *mov = nir_alu_instr_create(state->mem_ctx, nir_op_imov);
+ mov->src[0].src = nir_src_copy(intrin->src[0], state->mem_ctx);
+ mov->dest.write_mask = (1 << num_components) - 1;
+ mov->dest.dest.is_ssa = false;
+ mov->dest.dest.reg.reg = reg_src.reg.reg;
+ mov->dest.dest.reg.base_offset = reg_src.reg.base_offset;
+ mov->dest.dest.reg.indirect = reg_src.reg.indirect;
+
+ nir_instr_insert_before(&intrin->instr, &mov->instr);
+
+ nir_instr_remove(&intrin->instr);
+ break;
+ }
+
+ case nir_intrinsic_copy_var:
+ unreachable("There should be no copies whatsoever at this point");
+ break;
+
+ default:
+ continue;
+ }
+ }
+
+ return true;
+}
+
+static void
+nir_lower_locals_to_regs_impl(nir_function_impl *impl)
+{
+ struct locals_to_regs_state state;
+
+ state.mem_ctx = ralloc_parent(impl);
+ state.impl = impl;
+ state.regs_table = _mesa_hash_table_create(NULL, hash_deref, derefs_equal);
+
+ nir_foreach_block(impl, lower_locals_to_regs_block, &state);
+
+ _mesa_hash_table_destroy(state.regs_table, NULL);
+}
+
+void
+nir_lower_locals_to_regs(nir_shader *shader)
+{
+ nir_foreach_overload(shader, overload) {
+ if (overload->impl)
+ nir_lower_locals_to_regs_impl(overload->impl);
+ }
+}
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