src/gallium/drivers/vc4/vc4_qir_emit_uniform_stream_resets.c

/*
 * Copyright © 2014 Broadcom
 *
 * 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.
 */

/**
 * @file vc4_qir_emit_uniform_stream_resets.c
 *
 * Adds updates to the uniform stream address at the start of each basic block
 * that uses uniforms.
 *
 * This will be done just before the translation to QPU instructions, once we
 * have performed optimization know how many uniforms are used in each block.
 */

#include "vc4_qir.h"
#include "util/hash_table.h"
#include "util/u_math.h"

static bool
block_reads_any_uniform(struct qblock *block)
{
        qir_for_each_inst(inst, block) {
                if (qir_has_uniform_read(inst))
                        return true;
        }

        return false;
}

void
qir_emit_uniform_stream_resets(struct vc4_compile *c)
{
        uint32_t uniform_count = 0;

        qir_for_each_block(block, c) {
                if (block != qir_entry_block(c) &&
                    (block_reads_any_uniform(block) ||
                     block == qir_exit_block(c))) {
                        struct qreg t = qir_get_temp(c);
                        struct qreg uni_addr =
                                qir_uniform(c, QUNIFORM_UNIFORMS_ADDRESS, 0);

                        /* Load the offset of the next uniform in the stream
                         * after the one we're generating here.
                         */
                        struct qinst *load_imm =
                                qir_inst(QOP_LOAD_IMM,
                                         t,
                                         qir_reg(QFILE_LOAD_IMM,
                                                 (uniform_count + 1) * 4),
                                         c->undef);
                        struct qinst *add =
                                qir_inst(QOP_UNIFORMS_RESET, c->undef,
                                         t, uni_addr);

                        /* Pushes to the top of the block, so in reverse
                         * order.
                         */
                        list_add(&add->link, &block->instructions);
                        list_add(&load_imm->link, &block->instructions);
                }

                qir_for_each_inst(inst, block) {
                        if (qir_has_uniform_read(inst))
                                uniform_count++;
                }
        }
}