pan/midgard: Remove undefined behavior
[mesa.git] / src / panfrost / midgard / compiler.h
1 /*
2 * Copyright (C) 2019 Alyssa Rosenzweig <alyssa@rosenzweig.io>
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 #ifndef _MDG_COMPILER_H
25 #define _MDG_COMPILER_H
26
27 #include "midgard.h"
28 #include "helpers.h"
29 #include "midgard_compile.h"
30 #include "lcra.h"
31
32 #include "util/hash_table.h"
33 #include "util/u_dynarray.h"
34 #include "util/set.h"
35 #include "util/list.h"
36
37 #include "main/mtypes.h"
38 #include "compiler/nir_types.h"
39 #include "compiler/nir/nir.h"
40
41 /* Forward declare */
42 struct midgard_block;
43
44 /* Target types. Defaults to TARGET_GOTO (the type corresponding directly to
45 * the hardware), hence why that must be zero. TARGET_DISCARD signals this
46 * instruction is actually a discard op. */
47
48 #define TARGET_GOTO 0
49 #define TARGET_BREAK 1
50 #define TARGET_CONTINUE 2
51 #define TARGET_DISCARD 3
52
53 typedef struct midgard_branch {
54 /* If conditional, the condition is specified in r31.w */
55 bool conditional;
56
57 /* For conditionals, if this is true, we branch on FALSE. If false, we branch on TRUE. */
58 bool invert_conditional;
59
60 /* Branch targets: the start of a block, the start of a loop (continue), the end of a loop (break). Value is one of TARGET_ */
61 unsigned target_type;
62
63 /* The actual target */
64 union {
65 int target_block;
66 int target_break;
67 int target_continue;
68 };
69 } midgard_branch;
70
71 /* Generic in-memory data type repesenting a single logical instruction, rather
72 * than a single instruction group. This is the preferred form for code gen.
73 * Multiple midgard_insturctions will later be combined during scheduling,
74 * though this is not represented in this structure. Its format bridges
75 * the low-level binary representation with the higher level semantic meaning.
76 *
77 * Notably, it allows registers to be specified as block local SSA, for code
78 * emitted before the register allocation pass.
79 */
80
81 #define MIR_SRC_COUNT 3
82 #define MIR_VEC_COMPONENTS 16
83
84 typedef struct midgard_instruction {
85 /* Must be first for casting */
86 struct list_head link;
87
88 unsigned type; /* ALU, load/store, texture */
89
90 /* Instruction arguments represented as block-local SSA
91 * indices, rather than registers. ~0 means unused. */
92 unsigned src[3];
93 unsigned dest;
94
95 /* vec16 swizzle, unpacked, per source */
96 unsigned swizzle[MIR_SRC_COUNT][MIR_VEC_COMPONENTS];
97
98 /* Special fields for an ALU instruction */
99 midgard_reg_info registers;
100
101 /* I.e. (1 << alu_bit) */
102 int unit;
103
104 bool has_constants;
105 uint32_t constants[4];
106 uint16_t inline_constant;
107 bool has_blend_constant;
108 bool has_inline_constant;
109
110 bool compact_branch;
111 bool writeout;
112 bool prepacked_branch;
113
114 /* Kind of a hack, but hint against aggressive DCE */
115 bool dont_eliminate;
116
117 /* Masks in a saneish format. One bit per channel, not packed fancy.
118 * Use this instead of the op specific ones, and switch over at emit
119 * time */
120
121 uint16_t mask;
122
123 /* For ALU ops only: set to true to invert (bitwise NOT) the
124 * destination of an integer-out op. Not imeplemented in hardware but
125 * allows more optimizations */
126
127 bool invert;
128
129 /* Hint for the register allocator not to spill the destination written
130 * from this instruction (because it is a spill/unspill node itself) */
131
132 bool no_spill;
133
134 /* Generic hint for intra-pass use */
135 bool hint;
136
137 /* During scheduling, the backwards dependency graph
138 * (DAG). nr_dependencies is the number of unscheduled
139 * instructions that must still be scheduled after
140 * (before) this instruction. dependents are which
141 * instructions need to be scheduled before (after) this
142 * instruction. */
143
144 unsigned nr_dependencies;
145 BITSET_WORD *dependents;
146
147 /* For load/store ops.. force 64-bit destination */
148 bool load_64;
149
150 union {
151 midgard_load_store_word load_store;
152 midgard_vector_alu alu;
153 midgard_texture_word texture;
154 midgard_branch_extended branch_extended;
155 uint16_t br_compact;
156
157 /* General branch, rather than packed br_compact. Higher level
158 * than the other components */
159 midgard_branch branch;
160 };
161 } midgard_instruction;
162
163 typedef struct midgard_block {
164 /* Link to next block. Must be first for mir_get_block */
165 struct list_head link;
166
167 /* List of midgard_instructions emitted for the current block */
168 struct list_head instructions;
169
170 /* Index of the block in source order */
171 unsigned source_id;
172
173 bool is_scheduled;
174
175 /* List of midgard_bundles emitted (after the scheduler has run) */
176 struct util_dynarray bundles;
177
178 /* Number of quadwords _actually_ emitted, as determined after scheduling */
179 unsigned quadword_count;
180
181 /* Succeeding blocks. The compiler should not necessarily rely on
182 * source-order traversal */
183 struct midgard_block *successors[2];
184 unsigned nr_successors;
185
186 struct set *predecessors;
187
188 /* The successors pointer form a graph, and in the case of
189 * complex control flow, this graph has a cycles. To aid
190 * traversal during liveness analysis, we have a visited?
191 * boolean for passes to use as they see fit, provided they
192 * clean up later */
193 bool visited;
194
195 /* In liveness analysis, these are live masks (per-component) for
196 * indices for the block. Scalar compilers have the luxury of using
197 * simple bit fields, but for us, liveness is a vector idea. */
198 uint16_t *live_in;
199 uint16_t *live_out;
200 } midgard_block;
201
202 typedef struct midgard_bundle {
203 /* Tag for the overall bundle */
204 int tag;
205
206 /* Instructions contained by the bundle. instruction_count <= 6 (vmul,
207 * sadd, vadd, smul, vlut, branch) */
208 int instruction_count;
209 midgard_instruction *instructions[6];
210
211 /* Bundle-wide ALU configuration */
212 int padding;
213 int control;
214 bool has_embedded_constants;
215 float constants[4];
216 bool has_blend_constant;
217 } midgard_bundle;
218
219 typedef struct compiler_context {
220 nir_shader *nir;
221 gl_shader_stage stage;
222
223 /* Is internally a blend shader? Depends on stage == FRAGMENT */
224 bool is_blend;
225
226 /* Tracking for blend constant patching */
227 int blend_constant_offset;
228
229 /* Number of bytes used for Thread Local Storage */
230 unsigned tls_size;
231
232 /* Count of spills and fills for shaderdb */
233 unsigned spills;
234 unsigned fills;
235
236 /* Current NIR function */
237 nir_function *func;
238
239 /* Allocated compiler temporary counter */
240 unsigned temp_alloc;
241
242 /* Unordered list of midgard_blocks */
243 int block_count;
244 struct list_head blocks;
245
246 /* TODO merge with block_count? */
247 unsigned block_source_count;
248
249 /* List of midgard_instructions emitted for the current block */
250 midgard_block *current_block;
251
252 /* If there is a preset after block, use this, otherwise emit_block will create one if NULL */
253 midgard_block *after_block;
254
255 /* The current "depth" of the loop, for disambiguating breaks/continues
256 * when using nested loops */
257 int current_loop_depth;
258
259 /* Total number of loops for shader-db */
260 unsigned loop_count;
261
262 /* Constants which have been loaded, for later inlining */
263 struct hash_table_u64 *ssa_constants;
264
265 /* Mapping of hashes computed from NIR indices to the sequential temp indices ultimately used in MIR */
266 struct hash_table_u64 *hash_to_temp;
267 int temp_count;
268 int max_hash;
269
270 /* Just the count of the max register used. Higher count => higher
271 * register pressure */
272 int work_registers;
273
274 /* Used for cont/last hinting. Increase when a tex op is added.
275 * Decrease when a tex op is removed. */
276 int texture_op_count;
277
278 /* The number of uniforms allowable for the fast path */
279 int uniform_cutoff;
280
281 /* Count of instructions emitted from NIR overall, across all blocks */
282 int instruction_count;
283
284 /* Alpha ref value passed in */
285 float alpha_ref;
286
287 unsigned quadword_count;
288
289 /* The mapping of sysvals to uniforms, the count, and the off-by-one inverse */
290 unsigned sysvals[MAX_SYSVAL_COUNT];
291 unsigned sysval_count;
292 struct hash_table_u64 *sysval_to_id;
293
294 /* Bitmask of valid metadata */
295 unsigned metadata;
296
297 /* Model-specific quirk set */
298 uint32_t quirks;
299 } compiler_context;
300
301 /* Per-block live_in/live_out */
302 #define MIDGARD_METADATA_LIVENESS (1 << 0)
303
304 /* Helpers for manipulating the above structures (forming the driver IR) */
305
306 /* Append instruction to end of current block */
307
308 static inline midgard_instruction *
309 mir_upload_ins(struct compiler_context *ctx, struct midgard_instruction ins)
310 {
311 midgard_instruction *heap = ralloc(ctx, struct midgard_instruction);
312 memcpy(heap, &ins, sizeof(ins));
313 return heap;
314 }
315
316 static inline midgard_instruction *
317 emit_mir_instruction(struct compiler_context *ctx, struct midgard_instruction ins)
318 {
319 midgard_instruction *u = mir_upload_ins(ctx, ins);
320 list_addtail(&u->link, &ctx->current_block->instructions);
321 return u;
322 }
323
324 static inline struct midgard_instruction *
325 mir_insert_instruction_before(struct compiler_context *ctx,
326 struct midgard_instruction *tag,
327 struct midgard_instruction ins)
328 {
329 struct midgard_instruction *u = mir_upload_ins(ctx, ins);
330 list_addtail(&u->link, &tag->link);
331 return u;
332 }
333
334 static inline void
335 mir_remove_instruction(struct midgard_instruction *ins)
336 {
337 list_del(&ins->link);
338 }
339
340 static inline midgard_instruction*
341 mir_prev_op(struct midgard_instruction *ins)
342 {
343 return list_last_entry(&(ins->link), midgard_instruction, link);
344 }
345
346 static inline midgard_instruction*
347 mir_next_op(struct midgard_instruction *ins)
348 {
349 return list_first_entry(&(ins->link), midgard_instruction, link);
350 }
351
352 #define mir_foreach_block(ctx, v) \
353 list_for_each_entry(struct midgard_block, v, &ctx->blocks, link)
354
355 #define mir_foreach_block_from(ctx, from, v) \
356 list_for_each_entry_from(struct midgard_block, v, from, &ctx->blocks, link)
357
358 #define mir_foreach_instr(ctx, v) \
359 list_for_each_entry(struct midgard_instruction, v, &ctx->current_block->instructions, link)
360
361 #define mir_foreach_instr_safe(ctx, v) \
362 list_for_each_entry_safe(struct midgard_instruction, v, &ctx->current_block->instructions, link)
363
364 #define mir_foreach_instr_in_block(block, v) \
365 list_for_each_entry(struct midgard_instruction, v, &block->instructions, link)
366 #define mir_foreach_instr_in_block_rev(block, v) \
367 list_for_each_entry_rev(struct midgard_instruction, v, &block->instructions, link)
368
369 #define mir_foreach_instr_in_block_safe(block, v) \
370 list_for_each_entry_safe(struct midgard_instruction, v, &block->instructions, link)
371
372 #define mir_foreach_instr_in_block_safe_rev(block, v) \
373 list_for_each_entry_safe_rev(struct midgard_instruction, v, &block->instructions, link)
374
375 #define mir_foreach_instr_in_block_from(block, v, from) \
376 list_for_each_entry_from(struct midgard_instruction, v, from, &block->instructions, link)
377
378 #define mir_foreach_instr_in_block_from_rev(block, v, from) \
379 list_for_each_entry_from_rev(struct midgard_instruction, v, from, &block->instructions, link)
380
381 #define mir_foreach_bundle_in_block(block, v) \
382 util_dynarray_foreach(&block->bundles, midgard_bundle, v)
383
384 #define mir_foreach_bundle_in_block_rev(block, v) \
385 util_dynarray_foreach_reverse(&block->bundles, midgard_bundle, v)
386
387 #define mir_foreach_instr_in_block_scheduled_rev(block, v) \
388 midgard_instruction* v; \
389 signed i = 0; \
390 mir_foreach_bundle_in_block_rev(block, _bundle) \
391 for (i = (_bundle->instruction_count - 1), v = _bundle->instructions[i]; \
392 i >= 0; \
393 --i, v = (i >= 0) ? _bundle->instructions[i] : NULL) \
394
395 #define mir_foreach_instr_global(ctx, v) \
396 mir_foreach_block(ctx, v_block) \
397 mir_foreach_instr_in_block(v_block, v)
398
399 #define mir_foreach_instr_global_safe(ctx, v) \
400 mir_foreach_block(ctx, v_block) \
401 mir_foreach_instr_in_block_safe(v_block, v)
402
403 #define mir_foreach_successor(blk, v) \
404 struct midgard_block *v; \
405 struct midgard_block **_v; \
406 for (_v = &blk->successors[0], \
407 v = *_v; \
408 v != NULL && _v < &blk->successors[2]; \
409 _v++, v = *_v) \
410
411 /* Based on set_foreach, expanded with automatic type casts */
412
413 #define mir_foreach_predecessor(blk, v) \
414 struct set_entry *_entry_##v; \
415 struct midgard_block *v; \
416 for (_entry_##v = _mesa_set_next_entry(blk->predecessors, NULL), \
417 v = (struct midgard_block *) (_entry_##v ? _entry_##v->key : NULL); \
418 _entry_##v != NULL; \
419 _entry_##v = _mesa_set_next_entry(blk->predecessors, _entry_##v), \
420 v = (struct midgard_block *) (_entry_##v ? _entry_##v->key : NULL))
421
422 #define mir_foreach_src(ins, v) \
423 for (unsigned v = 0; v < ARRAY_SIZE(ins->src); ++v)
424
425 static inline midgard_instruction *
426 mir_last_in_block(struct midgard_block *block)
427 {
428 return list_last_entry(&block->instructions, struct midgard_instruction, link);
429 }
430
431 static inline midgard_block *
432 mir_get_block(compiler_context *ctx, int idx)
433 {
434 struct list_head *lst = &ctx->blocks;
435
436 while ((idx--) + 1)
437 lst = lst->next;
438
439 return (struct midgard_block *) lst;
440 }
441
442 static inline midgard_block *
443 mir_exit_block(struct compiler_context *ctx)
444 {
445 midgard_block *last = list_last_entry(&ctx->blocks,
446 struct midgard_block, link);
447
448 /* The last block must be empty logically but contains branch writeout
449 * for fragment shaders */
450
451 assert(last->nr_successors == 0);
452
453 return last;
454 }
455
456 static inline bool
457 mir_is_alu_bundle(midgard_bundle *bundle)
458 {
459 return IS_ALU(bundle->tag);
460 }
461
462 /* Registers/SSA are distinguish in the backend by the bottom-most bit */
463
464 #define IS_REG (1)
465
466 static inline unsigned
467 make_compiler_temp(compiler_context *ctx)
468 {
469 return (ctx->func->impl->ssa_alloc + ctx->temp_alloc++) << 1;
470 }
471
472 static inline unsigned
473 make_compiler_temp_reg(compiler_context *ctx)
474 {
475 return ((ctx->func->impl->reg_alloc + ctx->temp_alloc++) << 1) | IS_REG;
476 }
477
478 static inline unsigned
479 nir_src_index(compiler_context *ctx, nir_src *src)
480 {
481 if (src->is_ssa)
482 return (src->ssa->index << 1) | 0;
483 else {
484 assert(!src->reg.indirect);
485 return (src->reg.reg->index << 1) | IS_REG;
486 }
487 }
488
489 static inline unsigned
490 nir_alu_src_index(compiler_context *ctx, nir_alu_src *src)
491 {
492 return nir_src_index(ctx, &src->src);
493 }
494
495 static inline unsigned
496 nir_dest_index(compiler_context *ctx, nir_dest *dst)
497 {
498 if (dst->is_ssa)
499 return (dst->ssa.index << 1) | 0;
500 else {
501 assert(!dst->reg.indirect);
502 return (dst->reg.reg->index << 1) | IS_REG;
503 }
504 }
505
506
507
508 /* MIR manipulation */
509
510 void mir_rewrite_index(compiler_context *ctx, unsigned old, unsigned new);
511 void mir_rewrite_index_src(compiler_context *ctx, unsigned old, unsigned new);
512 void mir_rewrite_index_dst(compiler_context *ctx, unsigned old, unsigned new);
513 void mir_rewrite_index_dst_single(midgard_instruction *ins, unsigned old, unsigned new);
514 void mir_rewrite_index_src_single(midgard_instruction *ins, unsigned old, unsigned new);
515 void mir_rewrite_index_src_swizzle(compiler_context *ctx, unsigned old, unsigned new, unsigned *swizzle);
516 bool mir_single_use(compiler_context *ctx, unsigned value);
517 bool mir_special_index(compiler_context *ctx, unsigned idx);
518 unsigned mir_use_count(compiler_context *ctx, unsigned value);
519 bool mir_is_written_before(compiler_context *ctx, midgard_instruction *ins, unsigned node);
520 uint16_t mir_bytemask_of_read_components(midgard_instruction *ins, unsigned node);
521 midgard_reg_mode mir_typesize(midgard_instruction *ins);
522 midgard_reg_mode mir_srcsize(midgard_instruction *ins, unsigned i);
523 unsigned mir_bytes_for_mode(midgard_reg_mode mode);
524 midgard_reg_mode mir_mode_for_destsize(unsigned size);
525 uint16_t mir_from_bytemask(uint16_t bytemask, midgard_reg_mode mode);
526 uint16_t mir_to_bytemask(midgard_reg_mode mode, unsigned mask);
527 uint16_t mir_bytemask(midgard_instruction *ins);
528 uint16_t mir_round_bytemask_down(uint16_t mask, midgard_reg_mode mode);
529 void mir_set_bytemask(midgard_instruction *ins, uint16_t bytemask);
530
531 /* MIR printing */
532
533 void mir_print_instruction(midgard_instruction *ins);
534 void mir_print_bundle(midgard_bundle *ctx);
535 void mir_print_block(midgard_block *block);
536 void mir_print_shader(compiler_context *ctx);
537 bool mir_nontrivial_source2_mod(midgard_instruction *ins);
538 bool mir_nontrivial_source2_mod_simple(midgard_instruction *ins);
539 bool mir_nontrivial_outmod(midgard_instruction *ins);
540
541 void mir_insert_instruction_before_scheduled(compiler_context *ctx, midgard_block *block, midgard_instruction *tag, midgard_instruction ins);
542 void mir_insert_instruction_after_scheduled(compiler_context *ctx, midgard_block *block, midgard_instruction *tag, midgard_instruction ins);
543 void mir_flip(midgard_instruction *ins);
544 void mir_compute_temp_count(compiler_context *ctx);
545
546 /* 'Intrinsic' move for aliasing */
547
548 static inline midgard_instruction
549 v_mov(unsigned src, unsigned dest)
550 {
551 midgard_instruction ins = {
552 .type = TAG_ALU_4,
553 .mask = 0xF,
554 .src = { SSA_UNUSED, src, SSA_UNUSED },
555 .swizzle = SWIZZLE_IDENTITY,
556 .dest = dest,
557 .alu = {
558 .op = midgard_alu_op_imov,
559 .reg_mode = midgard_reg_mode_32,
560 .dest_override = midgard_dest_override_none,
561 .outmod = midgard_outmod_int_wrap
562 },
563 };
564
565 return ins;
566 }
567
568 static inline bool
569 mir_has_arg(midgard_instruction *ins, unsigned arg)
570 {
571 if (!ins)
572 return false;
573
574 for (unsigned i = 0; i < ARRAY_SIZE(ins->src); ++i) {
575 if (ins->src[i] == arg)
576 return true;
577 }
578
579 return false;
580 }
581
582 /* Scheduling */
583
584 void schedule_program(compiler_context *ctx);
585
586 /* Broad types of register classes so we can handle special
587 * registers */
588
589 #define REG_CLASS_WORK 0
590 #define REG_CLASS_LDST 1
591 #define REG_CLASS_TEXR 3
592 #define REG_CLASS_TEXW 4
593
594 void mir_lower_special_reads(compiler_context *ctx);
595 struct lcra_state* allocate_registers(compiler_context *ctx, bool *spilled);
596 void install_registers(compiler_context *ctx, struct lcra_state *g);
597 void mir_liveness_ins_update(uint16_t *live, midgard_instruction *ins, unsigned max);
598 void mir_compute_liveness(compiler_context *ctx);
599 void mir_invalidate_liveness(compiler_context *ctx);
600 bool mir_is_live_after(compiler_context *ctx, midgard_block *block, midgard_instruction *start, int src);
601
602 void mir_create_pipeline_registers(compiler_context *ctx);
603
604 void
605 midgard_promote_uniforms(compiler_context *ctx, unsigned promoted_count);
606
607 midgard_instruction *
608 emit_ubo_read(
609 compiler_context *ctx,
610 nir_instr *instr,
611 unsigned dest,
612 unsigned offset,
613 nir_src *indirect_offset,
614 unsigned index);
615
616 void
617 emit_sysval_read(compiler_context *ctx, nir_instr *instr, signed dest_override, unsigned nr_components);
618
619 void
620 midgard_emit_derivatives(compiler_context *ctx, nir_alu_instr *instr);
621
622 void
623 midgard_lower_derivatives(compiler_context *ctx, midgard_block *block);
624
625 bool mir_op_computes_derivatives(gl_shader_stage stage, unsigned op);
626
627 /* Final emission */
628
629 void emit_binary_bundle(
630 compiler_context *ctx,
631 midgard_bundle *bundle,
632 struct util_dynarray *emission,
633 int next_tag);
634
635 bool
636 nir_undef_to_zero(nir_shader *shader);
637
638 void midgard_nir_lod_errata(nir_shader *shader);
639
640 /* Optimizations */
641
642 bool midgard_opt_copy_prop(compiler_context *ctx, midgard_block *block);
643 bool midgard_opt_combine_projection(compiler_context *ctx, midgard_block *block);
644 bool midgard_opt_varying_projection(compiler_context *ctx, midgard_block *block);
645 bool midgard_opt_dead_code_eliminate(compiler_context *ctx, midgard_block *block);
646 bool midgard_opt_dead_move_eliminate(compiler_context *ctx, midgard_block *block);
647
648 void midgard_lower_invert(compiler_context *ctx, midgard_block *block);
649 bool midgard_opt_not_propagate(compiler_context *ctx, midgard_block *block);
650 bool midgard_opt_fuse_src_invert(compiler_context *ctx, midgard_block *block);
651 bool midgard_opt_fuse_dest_invert(compiler_context *ctx, midgard_block *block);
652 bool midgard_opt_csel_invert(compiler_context *ctx, midgard_block *block);
653 bool midgard_opt_promote_fmov(compiler_context *ctx, midgard_block *block);
654
655 #endif