src/panfrost/bifrost/bifrost_compile.c

   1 /*
   2  * Copyright (C) 2020 Collabora Ltd.
   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  * Authors (Collabora):
  24  *      Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
  25  */
  26
  27 #include "main/mtypes.h"
  28 #include "compiler/glsl/glsl_to_nir.h"
  29 #include "compiler/nir_types.h"
  30 #include "main/imports.h"
  31 #include "compiler/nir/nir_builder.h"
  32
  33 #include "disassemble.h"
  34 #include "bifrost_compile.h"
  35 #include "compiler.h"
  36 #include "bi_quirks.h"
  37 #include "bi_print.h"
  38
  39 static bi_block *emit_cf_list(bi_context *ctx, struct exec_list *list);
  40 static bi_instruction *bi_emit_branch(bi_context *ctx);
  41 static void bi_block_add_successor(bi_block *block, bi_block *successor);
  42 static void bi_schedule_barrier(bi_context *ctx);
  43
  44 static void
  45 emit_jump(bi_context *ctx, nir_jump_instr *instr)
  46 {
  47         bi_instruction *branch = bi_emit_branch(ctx);
  48
  49         switch (instr->type) {
  50         case nir_jump_break:
  51                 branch->branch.target = ctx->break_block;
  52                 break;
  53         case nir_jump_continue:
  54                 branch->branch.target = ctx->continue_block;
  55                 break;
  56         default:
  57                 unreachable("Unhandled jump type");
  58         }
  59
  60         bi_block_add_successor(ctx->current_block, branch->branch.target);
  61 }
  62
  63 static void
  64 bi_emit_ld_vary(bi_context *ctx, nir_intrinsic_instr *instr)
  65 {
  66         bi_instruction ins = {
  67                 .type = BI_LOAD_VAR,
  68                 .load_vary = {
  69                         .load = {
  70                                 .location = nir_intrinsic_base(instr),
  71                                 .channels = instr->num_components,
  72                         },
  73                         .interp_mode = BIFROST_INTERP_DEFAULT, /* TODO */
  74                         .reuse = false, /* TODO */
  75                         .flat = instr->intrinsic != nir_intrinsic_load_interpolated_input
  76                 },
  77                 .dest = bir_dest_index(&instr->dest),
  78                 .dest_type = nir_type_float | nir_dest_bit_size(instr->dest),
  79         };
  80
  81         nir_src *offset = nir_get_io_offset_src(instr);
  82
  83         if (nir_src_is_const(*offset))
  84                 ins.load_vary.load.location += nir_src_as_uint(*offset);
  85         else
  86                 ins.src[0] = bir_src_index(offset);
  87
  88         bi_emit(ctx, ins);
  89 }
  90
  91 static void
  92 bi_emit_frag_out(bi_context *ctx, nir_intrinsic_instr *instr)
  93 {
  94         if (!ctx->emitted_atest) {
  95                 bi_instruction ins = {
  96                         .type = BI_ATEST
  97                 };
  98
  99                 bi_emit(ctx, ins);
 100                 bi_schedule_barrier(ctx);
 101                 ctx->emitted_atest = true;
 102         }
 103
 104         bi_instruction blend = {
 105                 .type = BI_BLEND,
 106                 .blend_location = nir_intrinsic_base(instr),
 107                 .src = {
 108                         bir_src_index(&instr->src[0])
 109                 }
 110         };
 111
 112         bi_emit(ctx, blend);
 113         bi_schedule_barrier(ctx);
 114 }
 115
 116 static struct bi_load
 117 bi_direct_load_for_instr(nir_intrinsic_instr *instr)
 118 {
 119         nir_src *offset = nir_get_io_offset_src(instr);
 120         assert(nir_src_is_const(*offset)); /* no indirects */
 121
 122         struct bi_load load = {
 123                 .location = nir_intrinsic_base(instr) + nir_src_as_uint(*offset),
 124                 .channels = instr->num_components
 125         };
 126
 127         return load;
 128 }
 129
 130 static void
 131 bi_emit_ld_attr(bi_context *ctx, nir_intrinsic_instr *instr)
 132 {
 133         bi_instruction load = {
 134                 .type = BI_LOAD_ATTR,
 135                 .load = bi_direct_load_for_instr(instr),
 136                 .dest = bir_dest_index(&instr->dest),
 137                 .dest_type = nir_intrinsic_type(instr)
 138         };
 139
 140         bi_emit(ctx, load);
 141 }
 142
 143 static void
 144 bi_emit_st_vary(bi_context *ctx, nir_intrinsic_instr *instr)
 145 {
 146         nir_src *offset = nir_get_io_offset_src(instr);
 147         assert(nir_src_is_const(*offset)); /* no indirects */
 148
 149         bi_instruction address = {
 150                 .type = BI_LOAD_VAR_ADDRESS,
 151                 .load = bi_direct_load_for_instr(instr),
 152                 .dest_type = nir_intrinsic_type(instr),
 153                 .dest = bi_make_temp(ctx)
 154         };
 155
 156         bi_instruction st = {
 157                 .type = BI_STORE_VAR,
 158                 .src = {
 159                         address.dest,
 160                         bir_src_index(&instr->src[0])
 161                 }
 162         };
 163
 164         bi_emit(ctx, address);
 165         bi_emit(ctx, st);
 166 }
 167
 168 static void
 169 bi_emit_ld_uniform(bi_context *ctx, nir_intrinsic_instr *instr)
 170 {
 171         /* TODO: Indirect access */
 172
 173         bi_instruction ld = {
 174                 .type = BI_LOAD_UNIFORM,
 175                 .load = bi_direct_load_for_instr(instr),
 176                 .dest = bir_dest_index(&instr->dest),
 177                 .dest_type = nir_intrinsic_type(instr),
 178                 .src = {
 179                         BIR_INDEX_ZERO /* TODO: UBOs */
 180                 }
 181         };
 182
 183         bi_emit(ctx, ld);
 184 }
 185
 186 static void
 187 emit_intrinsic(bi_context *ctx, nir_intrinsic_instr *instr)
 188 {
 189
 190         switch (instr->intrinsic) {
 191         case nir_intrinsic_load_barycentric_pixel:
 192                 /* stub */
 193                 break;
 194         case nir_intrinsic_load_interpolated_input:
 195         case nir_intrinsic_load_input:
 196                 if (ctx->stage == MESA_SHADER_FRAGMENT)
 197                         bi_emit_ld_vary(ctx, instr);
 198                 else if (ctx->stage == MESA_SHADER_VERTEX)
 199                         bi_emit_ld_attr(ctx, instr);
 200                 else {
 201                         unreachable("Unsupported shader stage");
 202                 }
 203                 break;
 204
 205         case nir_intrinsic_store_output:
 206                 if (ctx->stage == MESA_SHADER_FRAGMENT)
 207                         bi_emit_frag_out(ctx, instr);
 208                 else if (ctx->stage == MESA_SHADER_VERTEX)
 209                         bi_emit_st_vary(ctx, instr);
 210                 else
 211                         unreachable("Unsupported shader stage");
 212                 break;
 213
 214         case nir_intrinsic_load_uniform:
 215                 bi_emit_ld_uniform(ctx, instr);
 216                 break;
 217
 218         default:
 219                 /* todo */
 220                 break;
 221         }
 222 }
 223
 224 static void
 225 emit_load_const(bi_context *ctx, nir_load_const_instr *instr)
 226 {
 227         /* Make sure we've been lowered */
 228         assert(instr->def.num_components == 1);
 229
 230         bi_instruction move = {
 231                 .type = BI_MOV,
 232                 .dest = bir_ssa_index(&instr->def),
 233                 .dest_type = instr->def.bit_size | nir_type_uint,
 234                 .src = {
 235                         BIR_INDEX_CONSTANT
 236                 },
 237                 .constant = {
 238                         .u64 = nir_const_value_as_uint(instr->value[0], instr->def.bit_size)
 239                 }
 240         };
 241
 242         bi_emit(ctx, move);
 243 }
 244
 245 static void
 246 emit_instr(bi_context *ctx, struct nir_instr *instr)
 247 {
 248         switch (instr->type) {
 249         case nir_instr_type_load_const:
 250                 emit_load_const(ctx, nir_instr_as_load_const(instr));
 251                 break;
 252
 253         case nir_instr_type_intrinsic:
 254                 emit_intrinsic(ctx, nir_instr_as_intrinsic(instr));
 255                 break;
 256
 257 #if 0
 258         case nir_instr_type_alu:
 259                 emit_alu(ctx, nir_instr_as_alu(instr));
 260                 break;
 261
 262         case nir_instr_type_tex:
 263                 emit_tex(ctx, nir_instr_as_tex(instr));
 264                 break;
 265 #endif
 266
 267         case nir_instr_type_jump:
 268                 emit_jump(ctx, nir_instr_as_jump(instr));
 269                 break;
 270
 271         case nir_instr_type_ssa_undef:
 272                 /* Spurious */
 273                 break;
 274
 275         default:
 276                 //unreachable("Unhandled instruction type");
 277                 break;
 278         }
 279 }
 280
 281
 282
 283 static bi_block *
 284 create_empty_block(bi_context *ctx)
 285 {
 286         bi_block *blk = rzalloc(ctx, bi_block);
 287
 288         blk->predecessors = _mesa_set_create(blk,
 289                         _mesa_hash_pointer,
 290                         _mesa_key_pointer_equal);
 291
 292         blk->name = ctx->block_name_count++;
 293
 294         return blk;
 295 }
 296
 297 static void
 298 bi_block_add_successor(bi_block *block, bi_block *successor)
 299 {
 300         assert(block);
 301         assert(successor);
 302
 303         for (unsigned i = 0; i < ARRAY_SIZE(block->successors); ++i) {
 304                 if (block->successors[i]) {
 305                        if (block->successors[i] == successor)
 306                                return;
 307                        else
 308                                continue;
 309                 }
 310
 311                 block->successors[i] = successor;
 312                 _mesa_set_add(successor->predecessors, block);
 313                 return;
 314         }
 315
 316         unreachable("Too many successors");
 317 }
 318
 319 static void
 320 bi_schedule_barrier(bi_context *ctx)
 321 {
 322         bi_block *temp = ctx->after_block;
 323         ctx->after_block = create_empty_block(ctx);
 324         list_addtail(&ctx->after_block->link, &ctx->blocks);
 325         list_inithead(&ctx->after_block->instructions);
 326         bi_block_add_successor(ctx->current_block, ctx->after_block);
 327         ctx->current_block = ctx->after_block;
 328         ctx->after_block = temp;
 329 }
 330
 331 static bi_block *
 332 emit_block(bi_context *ctx, nir_block *block)
 333 {
 334         if (ctx->after_block) {
 335                 ctx->current_block = ctx->after_block;
 336                 ctx->after_block = NULL;
 337         } else {
 338                 ctx->current_block = create_empty_block(ctx);
 339         }
 340
 341         list_addtail(&ctx->current_block->link, &ctx->blocks);
 342         list_inithead(&ctx->current_block->instructions);
 343
 344         nir_foreach_instr(instr, block) {
 345                 emit_instr(ctx, instr);
 346                 ++ctx->instruction_count;
 347         }
 348
 349         return ctx->current_block;
 350 }
 351
 352 /* Emits an unconditional branch to the end of the current block, returning a
 353  * pointer so the user can fill in details */
 354
 355 static bi_instruction *
 356 bi_emit_branch(bi_context *ctx)
 357 {
 358         bi_instruction branch = {
 359                 .type = BI_BRANCH,
 360                 .branch = {
 361                         .cond = BI_COND_ALWAYS
 362                 }
 363         };
 364
 365         return bi_emit(ctx, branch);
 366 }
 367
 368 /* Sets a condition for a branch by examing the NIR condition. If we're
 369  * familiar with the condition, we unwrap it to fold it into the branch
 370  * instruction. Otherwise, we consume the condition directly. We
 371  * generally use 1-bit booleans which allows us to use small types for
 372  * the conditions.
 373  */
 374
 375 static void
 376 bi_set_branch_cond(bi_instruction *branch, nir_src *cond, bool invert)
 377 {
 378         /* TODO: Try to unwrap instead of always bailing */
 379         branch->src[0] = bir_src_index(cond);
 380         branch->src[1] = BIR_INDEX_ZERO;
 381         branch->src_types[0] = branch->src_types[1] = nir_type_uint16;
 382         branch->branch.cond = invert ? BI_COND_EQ : BI_COND_NE;
 383 }
 384
 385 static void
 386 emit_if(bi_context *ctx, nir_if *nif)
 387 {
 388         bi_block *before_block = ctx->current_block;
 389
 390         /* Speculatively emit the branch, but we can't fill it in until later */
 391         bi_instruction *then_branch = bi_emit_branch(ctx);
 392         bi_set_branch_cond(then_branch, &nif->condition, true);
 393
 394         /* Emit the two subblocks. */
 395         bi_block *then_block = emit_cf_list(ctx, &nif->then_list);
 396         bi_block *end_then_block = ctx->current_block;
 397
 398         /* Emit a jump from the end of the then block to the end of the else */
 399         bi_instruction *then_exit = bi_emit_branch(ctx);
 400
 401         /* Emit second block, and check if it's empty */
 402
 403         int count_in = ctx->instruction_count;
 404         bi_block *else_block = emit_cf_list(ctx, &nif->else_list);
 405         bi_block *end_else_block = ctx->current_block;
 406         ctx->after_block = create_empty_block(ctx);
 407
 408         /* Now that we have the subblocks emitted, fix up the branches */
 409
 410         assert(then_block);
 411         assert(else_block);
 412
 413         if (ctx->instruction_count == count_in) {
 414                 /* The else block is empty, so don't emit an exit jump */
 415                 bi_remove_instruction(then_exit);
 416                 then_branch->branch.target = ctx->after_block;
 417         } else {
 418                 then_branch->branch.target = else_block;
 419                 then_exit->branch.target = ctx->after_block;
 420                 bi_block_add_successor(end_then_block, then_exit->branch.target);
 421         }
 422
 423         /* Wire up the successors */
 424
 425         bi_block_add_successor(before_block, then_branch->branch.target); /* then_branch */
 426
 427         bi_block_add_successor(before_block, then_block); /* fallthrough */
 428         bi_block_add_successor(end_else_block, ctx->after_block); /* fallthrough */
 429 }
 430
 431 static void
 432 emit_loop(bi_context *ctx, nir_loop *nloop)
 433 {
 434         /* Remember where we are */
 435         bi_block *start_block = ctx->current_block;
 436
 437         bi_block *saved_break = ctx->break_block;
 438         bi_block *saved_continue = ctx->continue_block;
 439
 440         ctx->continue_block = create_empty_block(ctx);
 441         ctx->break_block = create_empty_block(ctx);
 442         ctx->after_block = ctx->continue_block;
 443
 444         /* Emit the body itself */
 445         emit_cf_list(ctx, &nloop->body);
 446
 447         /* Branch back to loop back */
 448         bi_instruction *br_back = bi_emit_branch(ctx);
 449         br_back->branch.target = ctx->continue_block;
 450         bi_block_add_successor(start_block, ctx->continue_block);
 451         bi_block_add_successor(ctx->current_block, ctx->continue_block);
 452
 453         ctx->after_block = ctx->break_block;
 454
 455         /* Pop off */
 456         ctx->break_block = saved_break;
 457         ctx->continue_block = saved_continue;
 458         ++ctx->loop_count;
 459 }
 460
 461 static bi_block *
 462 emit_cf_list(bi_context *ctx, struct exec_list *list)
 463 {
 464         bi_block *start_block = NULL;
 465
 466         foreach_list_typed(nir_cf_node, node, node, list) {
 467                 switch (node->type) {
 468                 case nir_cf_node_block: {
 469                         bi_block *block = emit_block(ctx, nir_cf_node_as_block(node));
 470
 471                         if (!start_block)
 472                                 start_block = block;
 473
 474                         break;
 475                 }
 476
 477                 case nir_cf_node_if:
 478                         emit_if(ctx, nir_cf_node_as_if(node));
 479                         break;
 480
 481                 case nir_cf_node_loop:
 482                         emit_loop(ctx, nir_cf_node_as_loop(node));
 483                         break;
 484
 485                 default:
 486                         unreachable("Unknown control flow");
 487                 }
 488         }
 489
 490         return start_block;
 491 }
 492
 493 static int
 494 glsl_type_size(const struct glsl_type *type, bool bindless)
 495 {
 496         return glsl_count_attribute_slots(type, false);
 497 }
 498
 499 static void
 500 bi_optimize_nir(nir_shader *nir)
 501 {
 502         bool progress;
 503         unsigned lower_flrp = 16 | 32 | 64;
 504
 505         NIR_PASS(progress, nir, nir_lower_regs_to_ssa);
 506         NIR_PASS(progress, nir, nir_lower_idiv, nir_lower_idiv_fast);
 507
 508         nir_lower_tex_options lower_tex_options = {
 509                 .lower_txs_lod = true,
 510                 .lower_txp = ~0,
 511                 .lower_tex_without_implicit_lod = true,
 512                 .lower_txd = true,
 513         };
 514
 515         NIR_PASS(progress, nir, nir_lower_tex, &lower_tex_options);
 516         NIR_PASS(progress, nir, nir_lower_alu_to_scalar, NULL, NULL);
 517         NIR_PASS(progress, nir, nir_lower_load_const_to_scalar);
 518
 519         do {
 520                 progress = false;
 521
 522                 NIR_PASS(progress, nir, nir_lower_var_copies);
 523                 NIR_PASS(progress, nir, nir_lower_vars_to_ssa);
 524
 525                 NIR_PASS(progress, nir, nir_copy_prop);
 526                 NIR_PASS(progress, nir, nir_opt_remove_phis);
 527                 NIR_PASS(progress, nir, nir_opt_dce);
 528                 NIR_PASS(progress, nir, nir_opt_dead_cf);
 529                 NIR_PASS(progress, nir, nir_opt_cse);
 530                 NIR_PASS(progress, nir, nir_opt_peephole_select, 64, false, true);
 531                 NIR_PASS(progress, nir, nir_opt_algebraic);
 532                 NIR_PASS(progress, nir, nir_opt_constant_folding);
 533
 534                 if (lower_flrp != 0) {
 535                         bool lower_flrp_progress = false;
 536                         NIR_PASS(lower_flrp_progress,
 537                                  nir,
 538                                  nir_lower_flrp,
 539                                  lower_flrp,
 540                                  false /* always_precise */,
 541                                  nir->options->lower_ffma);
 542                         if (lower_flrp_progress) {
 543                                 NIR_PASS(progress, nir,
 544                                          nir_opt_constant_folding);
 545                                 progress = true;
 546                         }
 547
 548                         /* Nothing should rematerialize any flrps, so we only
 549                          * need to do this lowering once.
 550                          */
 551                         lower_flrp = 0;
 552                 }
 553
 554                 NIR_PASS(progress, nir, nir_opt_undef);
 555                 NIR_PASS(progress, nir, nir_opt_loop_unroll,
 556                          nir_var_shader_in |
 557                          nir_var_shader_out |
 558                          nir_var_function_temp);
 559         } while (progress);
 560
 561         NIR_PASS(progress, nir, nir_opt_algebraic_late);
 562         NIR_PASS(progress, nir, nir_lower_alu_to_scalar, NULL, NULL);
 563         NIR_PASS(progress, nir, nir_lower_load_const_to_scalar);
 564
 565         /* Take us out of SSA */
 566         NIR_PASS(progress, nir, nir_lower_locals_to_regs);
 567         NIR_PASS(progress, nir, nir_convert_from_ssa, true);
 568 }
 569
 570 void
 571 bifrost_compile_shader_nir(nir_shader *nir, bifrost_program *program, unsigned product_id)
 572 {
 573         bi_context *ctx = rzalloc(NULL, bi_context);
 574         ctx->nir = nir;
 575         ctx->stage = nir->info.stage;
 576         ctx->quirks = bifrost_get_quirks(product_id);
 577         list_inithead(&ctx->blocks);
 578
 579         /* Lower gl_Position pre-optimisation, but after lowering vars to ssa
 580          * (so we don't accidentally duplicate the epilogue since mesa/st has
 581          * messed with our I/O quite a bit already) */
 582
 583         NIR_PASS_V(nir, nir_lower_vars_to_ssa);
 584
 585         if (ctx->stage == MESA_SHADER_VERTEX) {
 586                 NIR_PASS_V(nir, nir_lower_viewport_transform);
 587                 NIR_PASS_V(nir, nir_lower_point_size, 1.0, 1024.0);
 588         }
 589
 590         NIR_PASS_V(nir, nir_split_var_copies);
 591         NIR_PASS_V(nir, nir_lower_global_vars_to_local);
 592         NIR_PASS_V(nir, nir_lower_var_copies);
 593         NIR_PASS_V(nir, nir_lower_vars_to_ssa);
 594         NIR_PASS_V(nir, nir_lower_io, nir_var_all, glsl_type_size, 0);
 595         NIR_PASS_V(nir, nir_lower_ssbo);
 596
 597         bi_optimize_nir(nir);
 598         nir_print_shader(nir, stdout);
 599
 600         nir_foreach_function(func, nir) {
 601                 if (!func->impl)
 602                         continue;
 603
 604                 ctx->impl = func->impl;
 605                 emit_cf_list(ctx, &func->impl->body);
 606                 break; /* TODO: Multi-function shaders */
 607         }
 608
 609         bi_print_shader(ctx, stdout);
 610         bi_schedule(ctx);
 611         bi_print_shader(ctx, stdout);
 612
 613         ralloc_free(ctx);
 614 }