--- /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.
+ */
+
+#include "nir.h"
+#include "nir_builder.h"
+#include "nir_builder_opcodes.h"
+#include "nir_intrinsics_indices.h"
+
+struct locals_to_regs_state {
+ nir_builder builder;
+
+ /* A hash table mapping derefs to register handles */
+ struct hash_table *regs_table;
+
+ /* Bit size to use for boolean registers */
+ uint8_t bool_bitsize;
+
+ bool progress;
+};
+
+/* 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)
+{
+ uint32_t hash = 0;
+
+ for (const nir_deref_instr *deref = void_deref; deref;
+ deref = nir_deref_instr_parent(deref)) {
+ switch (deref->deref_type) {
+ case nir_deref_type_var:
+ return XXH32(&deref->var, sizeof(deref->var), hash);
+
+ case nir_deref_type_array:
+ continue; /* Do nothing */
+
+ case nir_deref_type_struct:
+ hash = XXH32(&deref->strct.index, sizeof(deref->strct.index), hash);
+ continue;
+
+ default:
+ unreachable("Invalid deref type");
+ }
+ }
+
+ unreachable("We should have hit a variable dereference");
+}
+
+static bool
+derefs_equal(const void *void_a, const void *void_b)
+{
+ for (const nir_deref_instr *a = void_a, *b = void_b; a || b;
+ a = nir_deref_instr_parent(a), b = nir_deref_instr_parent(b)) {
+ if (a->deref_type != b->deref_type)
+ return false;
+
+ switch (a->deref_type) {
+ case nir_deref_type_var:
+ return a->var == b->var;
+
+ case nir_deref_type_array:
+ continue; /* Do nothing */
+
+ case nir_deref_type_struct:
+ if (a->strct.index != b->strct.index)
+ return false;
+ continue;
+
+ default:
+ unreachable("Invalid deref type");
+ }
+ }
+
+ unreachable("We should have hit a variable dereference");
+}
+
+static nir_ssa_def *
+get_reg_for_deref(nir_deref_instr *deref, struct locals_to_regs_state *state)
+{
+ uint32_t hash = hash_deref(deref);
+
+ assert(nir_deref_instr_get_variable(deref)->constant_initializer == NULL &&
+ nir_deref_instr_get_variable(deref)->pointer_initializer == NULL);
+
+ struct hash_entry *entry =
+ _mesa_hash_table_search_pre_hashed(state->regs_table, hash, deref);
+ if (entry)
+ return entry->data;
+
+ unsigned array_size = 1;
+ for (nir_deref_instr *d = deref; d; d = nir_deref_instr_parent(d)) {
+ if (d->deref_type == nir_deref_type_array)
+ array_size *= glsl_get_length(nir_deref_instr_parent(d)->type);
+ }
+
+ assert(glsl_type_is_vector_or_scalar(deref->type));
+
+ uint8_t bit_size = glsl_get_bit_size(deref->type);
+ if (bit_size == 1)
+ bit_size = state->bool_bitsize;
+
+ nir_ssa_def *reg = nir_decl_reg(&state->builder,
+ glsl_get_vector_elements(deref->type),
+ bit_size, array_size > 1 ? array_size : 0);
+
+ _mesa_hash_table_insert_pre_hashed(state->regs_table, hash, deref, reg);
+
+ return reg;
+}
+
+struct reg_location {
+ nir_ssa_def *reg;
+ nir_ssa_def *indirect;
+ unsigned base_offset;
+};
+
+static struct reg_location
+get_deref_reg_location(nir_deref_instr *deref,
+ struct locals_to_regs_state *state)
+{
+ nir_builder *b = &state->builder;
+
+ nir_ssa_def *reg = get_reg_for_deref(deref, state);
+ nir_intrinsic_instr *decl = nir_instr_as_intrinsic(reg->parent_instr);
+
+ /* It is possible for a user to create a shader that has an array with a
+ * single element and then proceed to access it indirectly. Indirectly
+ * accessing a non-array register is not allowed in NIR. In order to
+ * handle this case we just convert it to a direct reference.
+ */
+ if (nir_intrinsic_num_array_elems(decl) == 0)
+ return (struct reg_location){.reg = reg};
+
+ nir_ssa_def *indirect = NULL;
+ unsigned base_offset = 0;
+
+ unsigned inner_array_size = 1;
+ for (const nir_deref_instr *d = deref; d; d = nir_deref_instr_parent(d)) {
+ if (d->deref_type != nir_deref_type_array)
+ continue;
+
+ if (nir_src_is_const(d->arr.index) && !indirect) {
+ base_offset += nir_src_as_uint(d->arr.index) * inner_array_size;
+ } else {
+ if (indirect) {
+ assert(base_offset == 0);
+ } else {
+ indirect = nir_imm_int(b, base_offset);
+ base_offset = 0;
+ }
+
+ nir_ssa_def *index = nir_i2iN(b, nir_ssa_for_src(b, d->arr.index, 1), 32);
+ nir_ssa_def *offset = nir_imul_imm(b, index, inner_array_size);
+
+ /* Avoid emitting iadd with 0, which is otherwise common, since this
+ * pass runs late enough that nothing will clean it up.
+ */
+ nir_ssa_scalar scal = nir_get_ssa_scalar(indirect, 0);
+ if (nir_ssa_scalar_is_const(scal))
+ indirect = nir_iadd_imm(b, offset, nir_ssa_scalar_as_uint(scal));
+ else
+ indirect = nir_iadd(b, offset, indirect);
+ }
+
+ inner_array_size *= glsl_get_length(nir_deref_instr_parent(d)->type);
+ }
+
+ return (struct reg_location){
+ .reg = reg,
+ .indirect = indirect,
+ .base_offset = base_offset
+ };
+}
+
+static bool
+lower_locals_to_regs_block(nir_block *block,
+ struct locals_to_regs_state *state)
+{
+ nir_builder *b = &state->builder;
+
+ nir_foreach_instr_safe(instr, block) {
+ if (instr->type != nir_instr_type_intrinsic)
+ continue;
+
+ nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr);
+
+ switch (intrin->intrinsic) {
+ case nir_intrinsic_load_deref: {
+ nir_deref_instr *deref = nir_src_as_deref(intrin->src[0]);
+ if (!nir_deref_mode_is(deref, nir_var_function_temp))
+ continue;
+
+ b->cursor = nir_after_instr(&intrin->instr);
+ struct reg_location loc = get_deref_reg_location(deref, state);
+ nir_intrinsic_instr *decl = nir_reg_get_decl(loc.reg);
+
+ nir_ssa_def *value;
+ unsigned num_array_elems = nir_intrinsic_num_array_elems(decl);
+ unsigned num_components = nir_intrinsic_num_components(decl);
+ unsigned bit_size = nir_intrinsic_bit_size(decl);
+
+ if (loc.base_offset >= MAX2(num_array_elems, 1)) {
+ /* out-of-bounds read, return 0 instead. */
+ value = nir_imm_zero(b, num_components, bit_size);
+ } else if (loc.indirect != NULL) {
+ value = nir_load_reg_indirect(b, num_components, bit_size,
+ loc.reg, loc.indirect,
+ .base = loc.base_offset);
+ } else {
+ value = nir_build_load_reg(b, num_components, bit_size,
+ loc.reg, .base = loc.base_offset);
+ }
+
+ assert(intrin->dest.is_ssa);
+ nir_ssa_def_rewrite_uses(&intrin->dest.ssa, value);
+ nir_instr_remove(&intrin->instr);
+ state->progress = true;
+ break;
+ }
+
+ case nir_intrinsic_store_deref: {
+ nir_deref_instr *deref = nir_src_as_deref(intrin->src[0]);
+ if (!nir_deref_mode_is(deref, nir_var_function_temp))
+ continue;
+
+ b->cursor = nir_before_instr(&intrin->instr);
+
+ struct reg_location loc = get_deref_reg_location(deref, state);
+ nir_intrinsic_instr *decl = nir_reg_get_decl(loc.reg);
+
+ assert(intrin->src[1].is_ssa);
+ nir_ssa_def *val = intrin->src[1].ssa;
+ unsigned num_array_elems = nir_intrinsic_num_array_elems(decl);
+ unsigned write_mask = nir_intrinsic_write_mask(intrin);
+
+ if (loc.base_offset >= MAX2(num_array_elems, 1)) {
+ /* Out of bounds write, just eliminate it. */
+ } else if (loc.indirect) {
+ nir_store_reg_indirect(b, val, loc.reg, loc.indirect,
+ .base = loc.base_offset,
+ .write_mask = write_mask);
+ } else {
+ nir_build_store_reg(b, val, loc.reg, .base = loc.base_offset,
+ .write_mask = write_mask);
+ }
+
+ nir_instr_remove(&intrin->instr);
+ state->progress = true;
+ break;
+ }
+
+ case nir_intrinsic_copy_deref:
+ unreachable("There should be no copies whatsoever at this point");
+ break;
+
+ default:
+ continue;
+ }
+ }
+
+ return true;
+}
+
+static bool
+impl(nir_function_impl *impl, uint8_t bool_bitsize)
+{
+ struct locals_to_regs_state state;
+
+ state.builder = nir_builder_create(impl);
+ state.progress = false;
+ state.regs_table = _mesa_hash_table_create(NULL, hash_deref, derefs_equal);
+ state.bool_bitsize = bool_bitsize;
+
+ nir_metadata_require(impl, nir_metadata_dominance);
+
+ nir_foreach_block(block, impl) {
+ lower_locals_to_regs_block(block, &state);
+ }
+
+ nir_metadata_preserve(impl, nir_metadata_block_index |
+ nir_metadata_dominance);
+
+ _mesa_hash_table_destroy(state.regs_table, NULL);
+
+ return state.progress;
+}
+
+bool
+nir_lower_locals_to_reg_intrinsics(nir_shader *shader, uint8_t bool_bitsize)
+{
+ bool progress = false;
+
+ nir_foreach_function_impl(func_impl, shader) {
+ progress = impl(func_impl, bool_bitsize) || progress;
+ }
+
+ return progress;
+}
projects / platform / upstream / mesa.git / commitdiff