/*
* Copyright © 2020 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_builder.h"
#include <string.h>
/** Returns the type to use for a copy of the given size.
*
* The actual type doesn't matter here all that much as we're just going to do
* a load/store on it and never any arithmetic.
*/
static const struct glsl_type *
copy_type_for_byte_size(unsigned size)
{
switch (size) {
case 1: return glsl_vector_type(GLSL_TYPE_UINT8, 1);
case 2: return glsl_vector_type(GLSL_TYPE_UINT16, 1);
case 4: return glsl_vector_type(GLSL_TYPE_UINT, 1);
case 8: return glsl_vector_type(GLSL_TYPE_UINT, 2);
case 16: return glsl_vector_type(GLSL_TYPE_UINT, 4);
default:
unreachable("Unsupported size");
}
}
static nir_ssa_def *
memcpy_load_deref_elem(nir_builder *b, nir_deref_instr *parent,
nir_ssa_def *index)
{
nir_deref_instr *deref;
index = nir_i2i(b, index, nir_dest_bit_size(parent->dest));
assert(parent->deref_type == nir_deref_type_cast);
deref = nir_build_deref_ptr_as_array(b, parent, index);
return nir_load_deref(b, deref);
}
static nir_ssa_def *
memcpy_load_deref_elem_imm(nir_builder *b, nir_deref_instr *parent,
uint64_t index)
{
nir_ssa_def *idx = nir_imm_intN_t(b, index, parent->dest.ssa.bit_size);
return memcpy_load_deref_elem(b, parent, idx);
}
static void
memcpy_store_deref_elem(nir_builder *b, nir_deref_instr *parent,
nir_ssa_def *index, nir_ssa_def *value)
{
nir_deref_instr *deref;
index = nir_i2i(b, index, nir_dest_bit_size(parent->dest));
assert(parent->deref_type == nir_deref_type_cast);
deref = nir_build_deref_ptr_as_array(b, parent, index);
nir_store_deref(b, deref, value, ~0);
}
static void
memcpy_store_deref_elem_imm(nir_builder *b, nir_deref_instr *parent,
uint64_t index, nir_ssa_def *value)
{
nir_ssa_def *idx = nir_imm_intN_t(b, index, parent->dest.ssa.bit_size);
memcpy_store_deref_elem(b, parent, idx, value);
}
static bool
lower_memcpy_impl(nir_function_impl *impl)
{
nir_builder b;
nir_builder_init(&b, impl);
bool found_const_memcpy = false, found_non_const_memcpy = false;
nir_foreach_block_safe(block, impl) {
nir_foreach_instr_safe(instr, block) {
if (instr->type != nir_instr_type_intrinsic)
continue;
nir_intrinsic_instr *cpy = nir_instr_as_intrinsic(instr);
if (cpy->intrinsic != nir_intrinsic_memcpy_deref)
continue;
b.cursor = nir_instr_remove(&cpy->instr);
nir_deref_instr *dst = nir_src_as_deref(cpy->src[0]);
nir_deref_instr *src = nir_src_as_deref(cpy->src[1]);
if (nir_src_is_const(cpy->src[2])) {
found_const_memcpy = true;
uint64_t size = nir_src_as_uint(cpy->src[2]);
uint64_t offset = 0;
while (offset < size) {
uint64_t remaining = size - offset;
/* Find the largest chunk size power-of-two (MSB in remaining)
* and limit our chunk to 16B (a vec4). It's important to do as
* many 16B chunks as possible first so that the index
* computation is correct for
* memcpy_(load|store)_deref_elem_imm.
*/
unsigned copy_size = 1u << MIN2(util_last_bit64(remaining) - 1, 4);
const struct glsl_type *copy_type =
copy_type_for_byte_size(copy_size);
nir_deref_instr *copy_dst =
nir_build_deref_cast(&b, &dst->dest.ssa, dst->modes,
copy_type, copy_size);
nir_deref_instr *copy_src =
nir_build_deref_cast(&b, &src->dest.ssa, src->modes,
copy_type, copy_size);
uint64_t index = offset / copy_size;
nir_ssa_def *value =
memcpy_load_deref_elem_imm(&b, copy_src, index);
memcpy_store_deref_elem_imm(&b, copy_dst, index, value);
offset += copy_size;
}
} else {
found_non_const_memcpy = true;
assert(cpy->src[2].is_ssa);
nir_ssa_def *size = cpy->src[2].ssa;
/* In this case, we don't have any idea what the size is so we
* emit a loop which copies one byte at a time.
*/
nir_deref_instr *copy_dst =
nir_build_deref_cast(&b, &dst->dest.ssa, dst->modes,
glsl_uint8_t_type(), 1);
nir_deref_instr *copy_src =
nir_build_deref_cast(&b, &src->dest.ssa, src->modes,
glsl_uint8_t_type(), 1);
nir_variable *i = nir_local_variable_create(impl,
glsl_uintN_t_type(size->bit_size), NULL);
nir_store_var(&b, i, nir_imm_intN_t(&b, 0, size->bit_size), ~0);
nir_push_loop(&b);
{
nir_ssa_def *index = nir_load_var(&b, i);
nir_push_if(&b, nir_uge(&b, index, size));
{
nir_jump(&b, nir_jump_break);
}
nir_pop_if(&b, NULL);
nir_ssa_def *value =
memcpy_load_deref_elem(&b, copy_src, index);
memcpy_store_deref_elem(&b, copy_dst, index, value);
nir_store_var(&b, i, nir_iadd_imm(&b, index, 1), ~0);
}
nir_pop_loop(&b, NULL);
}
}
}
if (found_non_const_memcpy) {
nir_metadata_preserve(impl, nir_metadata_none);
} else if (found_const_memcpy) {
nir_metadata_preserve(impl, nir_metadata_block_index |
nir_metadata_dominance);
} else {
nir_metadata_preserve(impl, nir_metadata_all);
}
return found_const_memcpy || found_non_const_memcpy;
}
bool
nir_lower_memcpy(nir_shader *shader)
{
bool progress = false;
nir_foreach_function(function, shader) {
if (function->impl && lower_memcpy_impl(function->impl))
progress = true;
}
return progress;
}