mirror of https://gitlab.freedesktop.org/mesa/mesa
123 lines
4.1 KiB
C
123 lines
4.1 KiB
C
/*
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* Copyright (C) 2020 Collabora, Ltd.
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* Copyright (C) 2018-2019 Alyssa Rosenzweig <alyssa@rosenzweig.io>
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* Copyright © 2014 Intel Corporation
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice (including the next
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* paragraph) shall be included in all copies or substantial portions of the
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* Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*/
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#include "util/u_memory.h"
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#include "compiler.h"
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void
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bi_liveness_ins_update_ssa(BITSET_WORD *live, const bi_instr *I)
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{
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bi_foreach_dest(I, d)
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BITSET_CLEAR(live, I->dest[d].value);
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bi_foreach_ssa_src(I, s)
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BITSET_SET(live, I->src[s].value);
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}
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void
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bi_compute_liveness_ssa(bi_context *ctx)
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{
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u_worklist worklist;
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u_worklist_init(&worklist, ctx->num_blocks, NULL);
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/* Free any previous liveness, and allocate */
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unsigned words = BITSET_WORDS(ctx->ssa_alloc);
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bi_foreach_block(ctx, block) {
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if (block->ssa_live_in)
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ralloc_free(block->ssa_live_in);
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if (block->ssa_live_out)
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ralloc_free(block->ssa_live_out);
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block->ssa_live_in = rzalloc_array(block, BITSET_WORD, words);
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block->ssa_live_out = rzalloc_array(block, BITSET_WORD, words);
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bi_worklist_push_head(&worklist, block);
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}
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/* Iterate the work list */
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while (!u_worklist_is_empty(&worklist)) {
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/* Pop in reverse order since liveness is a backwards pass */
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bi_block *blk = bi_worklist_pop_head(&worklist);
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/* Update its liveness information */
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memcpy(blk->ssa_live_in, blk->ssa_live_out, words * sizeof(BITSET_WORD));
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bi_foreach_instr_in_block_rev(blk, I) {
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/* Phi nodes are handled separately, so we skip them. As phi nodes are
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* at the beginning and we're iterating backwards, we stop as soon as
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* we hit a phi node.
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*/
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if (I->op == BI_OPCODE_PHI)
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break;
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bi_liveness_ins_update_ssa(blk->ssa_live_in, I);
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}
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/* Propagate the live in of the successor (blk) to the live out of
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* predecessors.
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*
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* Phi nodes are logically on the control flow edge and act in parallel.
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* To handle when propagating, we kill writes from phis and make live the
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* corresponding sources.
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*/
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bi_foreach_predecessor(blk, pred) {
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BITSET_WORD *live = ralloc_array(blk, BITSET_WORD, words);
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memcpy(live, blk->ssa_live_in, words * sizeof(BITSET_WORD));
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/* Kill write */
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bi_foreach_instr_in_block(blk, I) {
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if (I->op != BI_OPCODE_PHI)
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break;
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BITSET_CLEAR(live, I->dest[0].value);
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}
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/* Make live the corresponding source */
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bi_foreach_instr_in_block(blk, I) {
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if (I->op != BI_OPCODE_PHI)
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break;
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bi_index operand = I->src[bi_predecessor_index(blk, *pred)];
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if (bi_is_ssa(operand))
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BITSET_SET(live, operand.value);
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}
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BITSET_WORD progress = 0;
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for (unsigned i = 0; i < words; ++i) {
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progress |= live[i] & ~((*pred)->ssa_live_out[i]);
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(*pred)->ssa_live_out[i] |= live[i];
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}
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if (progress != 0)
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bi_worklist_push_tail(&worklist, *pred);
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}
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}
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u_worklist_fini(&worklist);
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}
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