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      1 /*
      2  * Copyright (C) 2018-2019 Alyssa Rosenzweig <alyssa (at) rosenzweig.io>
      3  * Copyright (C) 2019-2020 Collabora, Ltd.
      4  *
      5  * Permission is hereby granted, free of charge, to any person obtaining a
      6  * copy of this software and associated documentation files (the "Software"),
      7  * to deal in the Software without restriction, including without limitation
      8  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
      9  * and/or sell copies of the Software, and to permit persons to whom the
     10  * Software is furnished to do so, subject to the following conditions:
     11  *
     12  * The above copyright notice and this permission notice (including the next
     13  * paragraph) shall be included in all copies or substantial portions of the
     14  * Software.
     15  *
     16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
     17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
     18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
     19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
     20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
     21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
     22  * SOFTWARE.
     23  */
     24 
     25 #include "compiler.h"
     26 
     27 void
     28 mir_liveness_ins_update(uint16_t *live, midgard_instruction *ins, unsigned max)
     29 {
     30         /* live_in[s] = GEN[s] + (live_out[s] - KILL[s]) */
     31 
     32         pan_liveness_kill(live, ins->dest, max, mir_bytemask(ins));
     33 
     34         mir_foreach_src(ins, src) {
     35                 unsigned node = ins->src[src];
     36                 unsigned bytemask = mir_bytemask_of_read_components(ins, node);
     37 
     38                 pan_liveness_gen(live, node, max, bytemask);
     39         }
     40 }
     41 
     42 static void
     43 mir_liveness_ins_update_wrap(uint16_t *live, void *ins, unsigned max)
     44 {
     45         mir_liveness_ins_update(live, (midgard_instruction *) ins, max);
     46 }
     47 
     48 void
     49 mir_compute_liveness(compiler_context *ctx)
     50 {
     51         /* If we already have fresh liveness, nothing to do */
     52         if (ctx->metadata & MIDGARD_METADATA_LIVENESS)
     53                 return;
     54 
     55         mir_compute_temp_count(ctx);
     56         pan_compute_liveness(&ctx->blocks, ctx->temp_count, mir_liveness_ins_update_wrap);
     57 
     58         /* Liveness is now valid */
     59         ctx->metadata |= MIDGARD_METADATA_LIVENESS;
     60 }
     61 
     62 /* Once liveness data is no longer valid, call this */
     63 
     64 void
     65 mir_invalidate_liveness(compiler_context *ctx)
     66 {
     67         /* If we didn't already compute liveness, there's nothing to do */
     68         if (!(ctx->metadata & MIDGARD_METADATA_LIVENESS))
     69                 return;
     70 
     71         pan_free_liveness(&ctx->blocks);
     72 
     73         /* It's now invalid regardless */
     74         ctx->metadata &= ~MIDGARD_METADATA_LIVENESS;
     75 }
     76 
     77 bool
     78 mir_is_live_after(compiler_context *ctx, midgard_block *block, midgard_instruction *start, int src)
     79 {
     80         mir_compute_liveness(ctx);
     81 
     82         /* Check whether we're live in the successors */
     83 
     84         if (pan_liveness_get(block->base.live_out, src, ctx->temp_count))
     85                 return true;
     86 
     87         /* Check the rest of the block for liveness */
     88 
     89         mir_foreach_instr_in_block_from(block, ins, mir_next_op(start)) {
     90                 if (mir_has_arg(ins, src))
     91                         return true;
     92         }
     93 
     94         return false;
     95 }
     96