[Mesa-dev] [PATCH 092/133] nir: Add a pass to lower local variables to registers
Connor Abbott
cwabbott0 at gmail.com
Wed Jan 14 15:43:48 PST 2015
Together with the patches to lower all wildcard copies,
Reviewed-by: Connor Abbott <cwabbott0 at gmail.com>
On Tue, Dec 16, 2014 at 1:11 AM, Jason Ekstrand <jason at jlekstrand.net> wrote:
> ---
> src/glsl/Makefile.sources | 1 +
> src/glsl/nir/nir.h | 2 +
> src/glsl/nir/nir_lower_locals_to_regs.c | 313 ++++++++++++++++++++++++++++++++
> 3 files changed, 316 insertions(+)
> create mode 100644 src/glsl/nir/nir_lower_locals_to_regs.c
>
> diff --git a/src/glsl/Makefile.sources b/src/glsl/Makefile.sources
> index 1d3b049..6230f49 100644
> --- a/src/glsl/Makefile.sources
> +++ b/src/glsl/Makefile.sources
> @@ -22,6 +22,7 @@ NIR_FILES = \
> $(GLSL_SRCDIR)/nir/nir_intrinsics.h \
> $(GLSL_SRCDIR)/nir/nir_live_variables.c \
> $(GLSL_SRCDIR)/nir/nir_lower_atomics.c \
> + $(GLSL_SRCDIR)/nir/nir_lower_locals_to_regs.c \
> $(GLSL_SRCDIR)/nir/nir_lower_samplers.cpp \
> $(GLSL_SRCDIR)/nir/nir_lower_system_values.c \
> $(GLSL_SRCDIR)/nir/nir_lower_variables.c \
> diff --git a/src/glsl/nir/nir.h b/src/glsl/nir/nir.h
> index b3abfb9..7d7aec7 100644
> --- a/src/glsl/nir/nir.h
> +++ b/src/glsl/nir/nir.h
> @@ -1358,6 +1358,8 @@ void nir_dump_cfg(nir_shader *shader, FILE *fp);
>
> void nir_split_var_copies(nir_shader *shader);
>
> +void nir_lower_locals_to_regs(nir_shader *shader);
> +
> void nir_lower_variables(nir_shader *shader);
>
> void nir_lower_variables_scalar(nir_shader *shader, bool lower_globals,
> diff --git a/src/glsl/nir/nir_lower_locals_to_regs.c b/src/glsl/nir/nir_lower_locals_to_regs.c
> new file mode 100644
> index 0000000..caf1c29
> --- /dev/null
> +++ b/src/glsl/nir/nir_lower_locals_to_regs.c
> @@ -0,0 +1,313 @@
> +/*
> + * 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 at 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(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(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, 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);
> + }
> +}
> --
> 2.2.0
>
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