src/freedreno/ir3/ir3_nir_analyze_ubo_ranges.c

   1 /*
   2  * Copyright © 2019 Google, Inc.
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  20  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  21  * SOFTWARE.
  22  */
  23
  24 #include "ir3_nir.h"
  25 #include "compiler/nir/nir.h"
  26 #include "compiler/nir/nir_builder.h"
  27 #include "util/u_dynarray.h"
  28 #include "mesa/main/macros.h"
  29
  30 static inline struct ir3_ubo_range
  31 get_ubo_load_range(nir_intrinsic_instr *instr)
  32 {
  33         struct ir3_ubo_range r;
  34
  35         const int bytes = nir_intrinsic_dest_components(instr) *
  36                 (nir_dest_bit_size(instr->dest) / 8);
  37
  38         r.start = ROUND_DOWN_TO(nir_src_as_uint(instr->src[1]), 16 * 4);
  39         r.end = ALIGN(r.start + bytes, 16 * 4);
  40
  41         return r;
  42 }
  43
  44 static void
  45 gather_ubo_ranges(nir_intrinsic_instr *instr,
  46                                   struct ir3_ubo_analysis_state *state)
  47 {
  48         if (!nir_src_is_const(instr->src[0]))
  49                 return;
  50
  51         if (!nir_src_is_const(instr->src[1]))
  52                 return;
  53
  54         const struct ir3_ubo_range r = get_ubo_load_range(instr);
  55         const uint32_t block = nir_src_as_uint(instr->src[0]);
  56
  57         if (r.start < state->range[block].start)
  58                 state->range[block].start = r.start;
  59         if (state->range[block].end < r.end)
  60                 state->range[block].end = r.end;
  61 }
  62
  63 static void
  64 lower_ubo_load_to_uniform(nir_intrinsic_instr *instr, nir_builder *b,
  65                                                   struct ir3_ubo_analysis_state *state)
  66 {
  67         /* We don't lower dynamic block index UBO loads to load_uniform, but we
  68          * could probably with some effort determine a block stride in number of
  69          * registers.
  70          */
  71         if (!nir_src_is_const(instr->src[0]))
  72                 return;
  73
  74         const uint32_t block = nir_src_as_uint(instr->src[0]);
  75
  76         if (block > 0) {
  77                 /* We don't lower dynamic array indexing either, but we definitely should.
  78                  * We don't have a good way of determining the range of the dynamic
  79                  * access, so for now just fall back to pulling.
  80                  */
  81                 if (!nir_src_is_const(instr->src[1]))
  82                         return;
  83
  84                 /* After gathering the UBO access ranges, we limit the total
  85                  * upload. Reject if we're now outside the range.
  86                  */
  87                 const struct ir3_ubo_range r = get_ubo_load_range(instr);
  88                 if (!(state->range[block].start <= r.start &&
  89                           r.end <= state->range[block].end))
  90                         return;
  91         }
  92
  93         b->cursor = nir_before_instr(&instr->instr);
  94
  95         nir_ssa_def *ubo_offset = nir_ssa_for_src(b, instr->src[1], 1);
  96         nir_ssa_def *new_offset = ir3_nir_try_propagate_bit_shift(b, ubo_offset, -2);
  97         if (new_offset)
  98                 ubo_offset = new_offset;
  99         else
 100                 ubo_offset = nir_ushr(b, ubo_offset, nir_imm_int(b, 2));
 101
 102         const int range_offset =
 103                 (state->range[block].offset - state->range[block].start) / 4;
 104         nir_ssa_def *uniform_offset =
 105                 nir_iadd(b, ubo_offset, nir_imm_int(b, range_offset));
 106
 107         nir_intrinsic_instr *uniform =
 108                 nir_intrinsic_instr_create(b->shader, nir_intrinsic_load_uniform);
 109         uniform->num_components = instr->num_components;
 110         uniform->src[0] = nir_src_for_ssa(uniform_offset);
 111         nir_ssa_dest_init(&uniform->instr, &uniform->dest,
 112                                           uniform->num_components, instr->dest.ssa.bit_size,
 113                                           instr->dest.ssa.name);
 114         nir_builder_instr_insert(b, &uniform->instr);
 115         nir_ssa_def_rewrite_uses(&instr->dest.ssa,
 116                                                          nir_src_for_ssa(&uniform->dest.ssa));
 117
 118         nir_instr_remove(&instr->instr);
 119
 120         state->lower_count++;
 121 }
 122
 123 bool
 124 ir3_nir_analyze_ubo_ranges(nir_shader *nir, struct ir3_shader *shader)
 125 {
 126         struct ir3_ubo_analysis_state *state = &shader->ubo_state;
 127
 128         memset(state, 0, sizeof(*state));
 129         state->range[0].end = align(nir->num_uniforms * 16, 16 * 4); /* align to 4*vec4 */
 130
 131         nir_foreach_function(function, nir) {
 132                 if (function->impl) {
 133                         nir_foreach_block(block, function->impl) {
 134                                 nir_foreach_instr(instr, block) {
 135                                         if (instr->type == nir_instr_type_intrinsic &&
 136                                                 nir_instr_as_intrinsic(instr)->intrinsic == nir_intrinsic_load_ubo)
 137                                                 gather_ubo_ranges(nir_instr_as_intrinsic(instr), state);
 138                                 }
 139                         }
 140                 }
 141         }
 142
 143         /* For now, everything we upload is accessed statically and thus will be
 144          * used by the shader. Once we can upload dynamically indexed data, we may
 145          * upload sparsely accessed arrays, at which point we probably want to
 146          * give priority to smaller UBOs, on the assumption that big UBOs will be
 147          * accessed dynamically.  Alternatively, we can track statically and
 148          * dynamically accessed ranges separately and upload static rangtes
 149          * first.
 150          */
 151         const uint32_t max_upload = 16 * 1024;
 152         uint32_t offset = 0;
 153         for (uint32_t i = 0; i < ARRAY_SIZE(state->range); i++) {
 154                 uint32_t range_size = state->range[i].end - state->range[i].start;
 155
 156                 debug_assert(offset <= max_upload);
 157                 state->range[i].offset = offset;
 158                 if (offset + range_size > max_upload) {
 159                         range_size = max_upload - offset;
 160                         state->range[i].end = state->range[i].start + range_size;
 161                 }
 162                 offset += range_size;
 163         }
 164         state->size = offset;
 165
 166         nir_foreach_function(function, nir) {
 167                 if (function->impl) {
 168                         nir_builder builder;
 169                         nir_builder_init(&builder, function->impl);
 170                         nir_foreach_block(block, function->impl) {
 171                                 nir_foreach_instr_safe(instr, block) {
 172                                         if (instr->type == nir_instr_type_intrinsic &&
 173                                                 nir_instr_as_intrinsic(instr)->intrinsic == nir_intrinsic_load_ubo)
 174                                                 lower_ubo_load_to_uniform(nir_instr_as_intrinsic(instr), &builder, state);
 175                                 }
 176                         }
 177
 178                         nir_metadata_preserve(function->impl, nir_metadata_block_index |
 179                                                                   nir_metadata_dominance);
 180                 }
 181         }
 182
 183         return state->lower_count > 0;
 184 }