1 /*
2 * Copyright © 2013 Intel Corporation
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
20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
21 * DEALINGS IN THE SOFTWARE.
22 */
23
24 /**
25 * \file brw_vec4_tcs.cpp
26 *
27 * Tessellaton control shader specific code derived from the vec4_visitor class.
28 */
29
30 #include "brw_nir.h"
31 #include "brw_vec4_tcs.h"
32 #include "brw_fs.h"
33 #include "dev/gen_debug.h"
34
35 namespace brw {
36
vec4_tcs_visitor(const struct brw_compiler * compiler,void * log_data,const struct brw_tcs_prog_key * key,struct brw_tcs_prog_data * prog_data,const nir_shader * nir,void * mem_ctx,int shader_time_index,const struct brw_vue_map * input_vue_map)37 vec4_tcs_visitor::vec4_tcs_visitor(const struct brw_compiler *compiler,
38 void *log_data,
39 const struct brw_tcs_prog_key *key,
40 struct brw_tcs_prog_data *prog_data,
41 const nir_shader *nir,
42 void *mem_ctx,
43 int shader_time_index,
44 const struct brw_vue_map *input_vue_map)
45 : vec4_visitor(compiler, log_data, &key->base.tex, &prog_data->base,
46 nir, mem_ctx, false, shader_time_index),
47 input_vue_map(input_vue_map), key(key)
48 {
49 }
50
51
52 void
setup_payload()53 vec4_tcs_visitor::setup_payload()
54 {
55 int reg = 0;
56
57 /* The payload always contains important data in r0, which contains
58 * the URB handles that are passed on to the URB write at the end
59 * of the thread.
60 */
61 reg++;
62
63 /* r1.0 - r4.7 may contain the input control point URB handles,
64 * which we use to pull vertex data.
65 */
66 reg += 4;
67
68 /* Push constants may start at r5.0 */
69 reg = setup_uniforms(reg);
70
71 this->first_non_payload_grf = reg;
72 }
73
74
75 void
emit_prolog()76 vec4_tcs_visitor::emit_prolog()
77 {
78 invocation_id = src_reg(this, glsl_type::uint_type);
79 emit(TCS_OPCODE_GET_INSTANCE_ID, dst_reg(invocation_id));
80
81 /* HS threads are dispatched with the dispatch mask set to 0xFF.
82 * If there are an odd number of output vertices, then the final
83 * HS instance dispatched will only have its bottom half doing real
84 * work, and so we need to disable the upper half:
85 */
86 if (nir->info.tess.tcs_vertices_out % 2) {
87 emit(CMP(dst_null_d(), invocation_id,
88 brw_imm_ud(nir->info.tess.tcs_vertices_out),
89 BRW_CONDITIONAL_L));
90
91 /* Matching ENDIF is in emit_thread_end() */
92 emit(IF(BRW_PREDICATE_NORMAL));
93 }
94 }
95
96
97 void
emit_thread_end()98 vec4_tcs_visitor::emit_thread_end()
99 {
100 vec4_instruction *inst;
101 current_annotation = "thread end";
102
103 if (nir->info.tess.tcs_vertices_out % 2) {
104 emit(BRW_OPCODE_ENDIF);
105 }
106
107 if (devinfo->gen == 7) {
108 struct brw_tcs_prog_data *tcs_prog_data =
109 (struct brw_tcs_prog_data *) prog_data;
110
111 current_annotation = "release input vertices";
112
113 /* Synchronize all threads, so we know that no one is still
114 * using the input URB handles.
115 */
116 if (tcs_prog_data->instances > 1) {
117 dst_reg header = dst_reg(this, glsl_type::uvec4_type);
118 emit(TCS_OPCODE_CREATE_BARRIER_HEADER, header);
119 emit(SHADER_OPCODE_BARRIER, dst_null_ud(), src_reg(header));
120 }
121
122 /* Make thread 0 (invocations <1, 0>) release pairs of ICP handles.
123 * We want to compare the bottom half of invocation_id with 0, but
124 * use that truth value for the top half as well. Unfortunately,
125 * we don't have stride in the vec4 world, nor UV immediates in
126 * align16, so we need an opcode to get invocation_id<0,4,0>.
127 */
128 set_condmod(BRW_CONDITIONAL_Z,
129 emit(TCS_OPCODE_SRC0_010_IS_ZERO, dst_null_d(),
130 invocation_id));
131 emit(IF(BRW_PREDICATE_NORMAL));
132 for (unsigned i = 0; i < key->input_vertices; i += 2) {
133 /* If we have an odd number of input vertices, the last will be
134 * unpaired. We don't want to use an interleaved URB write in
135 * that case.
136 */
137 const bool is_unpaired = i == key->input_vertices - 1;
138
139 dst_reg header(this, glsl_type::uvec4_type);
140 emit(TCS_OPCODE_RELEASE_INPUT, header, brw_imm_ud(i),
141 brw_imm_ud(is_unpaired));
142 }
143 emit(BRW_OPCODE_ENDIF);
144 }
145
146 if (INTEL_DEBUG & DEBUG_SHADER_TIME)
147 emit_shader_time_end();
148
149 inst = emit(TCS_OPCODE_THREAD_END);
150 inst->base_mrf = 14;
151 inst->mlen = 2;
152 }
153
154
155 void
emit_input_urb_read(const dst_reg & dst,const src_reg & vertex_index,unsigned base_offset,unsigned first_component,const src_reg & indirect_offset)156 vec4_tcs_visitor::emit_input_urb_read(const dst_reg &dst,
157 const src_reg &vertex_index,
158 unsigned base_offset,
159 unsigned first_component,
160 const src_reg &indirect_offset)
161 {
162 vec4_instruction *inst;
163 dst_reg temp(this, glsl_type::ivec4_type);
164 temp.type = dst.type;
165
166 /* Set up the message header to reference the proper parts of the URB */
167 dst_reg header = dst_reg(this, glsl_type::uvec4_type);
168 inst = emit(TCS_OPCODE_SET_INPUT_URB_OFFSETS, header, vertex_index,
169 indirect_offset);
170 inst->force_writemask_all = true;
171
172 /* Read into a temporary, ignoring writemasking. */
173 inst = emit(VEC4_OPCODE_URB_READ, temp, src_reg(header));
174 inst->offset = base_offset;
175 inst->mlen = 1;
176 inst->base_mrf = -1;
177
178 /* Copy the temporary to the destination to deal with writemasking.
179 *
180 * Also attempt to deal with gl_PointSize being in the .w component.
181 */
182 if (inst->offset == 0 && indirect_offset.file == BAD_FILE) {
183 emit(MOV(dst, swizzle(src_reg(temp), BRW_SWIZZLE_WWWW)));
184 } else {
185 src_reg src = src_reg(temp);
186 src.swizzle = BRW_SWZ_COMP_INPUT(first_component);
187 emit(MOV(dst, src));
188 }
189 }
190
191 void
emit_output_urb_read(const dst_reg & dst,unsigned base_offset,unsigned first_component,const src_reg & indirect_offset)192 vec4_tcs_visitor::emit_output_urb_read(const dst_reg &dst,
193 unsigned base_offset,
194 unsigned first_component,
195 const src_reg &indirect_offset)
196 {
197 vec4_instruction *inst;
198
199 /* Set up the message header to reference the proper parts of the URB */
200 dst_reg header = dst_reg(this, glsl_type::uvec4_type);
201 inst = emit(TCS_OPCODE_SET_OUTPUT_URB_OFFSETS, header,
202 brw_imm_ud(dst.writemask << first_component), indirect_offset);
203 inst->force_writemask_all = true;
204
205 vec4_instruction *read = emit(VEC4_OPCODE_URB_READ, dst, src_reg(header));
206 read->offset = base_offset;
207 read->mlen = 1;
208 read->base_mrf = -1;
209
210 if (first_component) {
211 /* Read into a temporary and copy with a swizzle and writemask. */
212 read->dst = retype(dst_reg(this, glsl_type::ivec4_type), dst.type);
213 emit(MOV(dst, swizzle(src_reg(read->dst),
214 BRW_SWZ_COMP_INPUT(first_component))));
215 }
216 }
217
218 void
emit_urb_write(const src_reg & value,unsigned writemask,unsigned base_offset,const src_reg & indirect_offset)219 vec4_tcs_visitor::emit_urb_write(const src_reg &value,
220 unsigned writemask,
221 unsigned base_offset,
222 const src_reg &indirect_offset)
223 {
224 if (writemask == 0)
225 return;
226
227 src_reg message(this, glsl_type::uvec4_type, 2);
228 vec4_instruction *inst;
229
230 inst = emit(TCS_OPCODE_SET_OUTPUT_URB_OFFSETS, dst_reg(message),
231 brw_imm_ud(writemask), indirect_offset);
232 inst->force_writemask_all = true;
233 inst = emit(MOV(byte_offset(dst_reg(retype(message, value.type)), REG_SIZE),
234 value));
235 inst->force_writemask_all = true;
236
237 inst = emit(TCS_OPCODE_URB_WRITE, dst_null_f(), message);
238 inst->offset = base_offset;
239 inst->mlen = 2;
240 inst->base_mrf = -1;
241 }
242
243 void
nir_emit_intrinsic(nir_intrinsic_instr * instr)244 vec4_tcs_visitor::nir_emit_intrinsic(nir_intrinsic_instr *instr)
245 {
246 switch (instr->intrinsic) {
247 case nir_intrinsic_load_invocation_id:
248 emit(MOV(get_nir_dest(instr->dest, BRW_REGISTER_TYPE_UD),
249 invocation_id));
250 break;
251 case nir_intrinsic_load_primitive_id:
252 emit(TCS_OPCODE_GET_PRIMITIVE_ID,
253 get_nir_dest(instr->dest, BRW_REGISTER_TYPE_UD));
254 break;
255 case nir_intrinsic_load_patch_vertices_in:
256 emit(MOV(get_nir_dest(instr->dest, BRW_REGISTER_TYPE_D),
257 brw_imm_d(key->input_vertices)));
258 break;
259 case nir_intrinsic_load_per_vertex_input: {
260 assert(nir_dest_bit_size(instr->dest) == 32);
261 src_reg indirect_offset = get_indirect_offset(instr);
262 unsigned imm_offset = instr->const_index[0];
263
264 src_reg vertex_index = retype(get_nir_src_imm(instr->src[0]),
265 BRW_REGISTER_TYPE_UD);
266
267 unsigned first_component = nir_intrinsic_component(instr);
268 dst_reg dst = get_nir_dest(instr->dest, BRW_REGISTER_TYPE_D);
269 dst.writemask = brw_writemask_for_size(instr->num_components);
270 emit_input_urb_read(dst, vertex_index, imm_offset,
271 first_component, indirect_offset);
272 break;
273 }
274 case nir_intrinsic_load_input:
275 unreachable("nir_lower_io should use load_per_vertex_input intrinsics");
276 break;
277 case nir_intrinsic_load_output:
278 case nir_intrinsic_load_per_vertex_output: {
279 src_reg indirect_offset = get_indirect_offset(instr);
280 unsigned imm_offset = instr->const_index[0];
281
282 dst_reg dst = get_nir_dest(instr->dest, BRW_REGISTER_TYPE_D);
283 dst.writemask = brw_writemask_for_size(instr->num_components);
284
285 emit_output_urb_read(dst, imm_offset, nir_intrinsic_component(instr),
286 indirect_offset);
287 break;
288 }
289 case nir_intrinsic_store_output:
290 case nir_intrinsic_store_per_vertex_output: {
291 assert(nir_src_bit_size(instr->src[0]) == 32);
292 src_reg value = get_nir_src(instr->src[0]);
293 unsigned mask = instr->const_index[1];
294 unsigned swiz = BRW_SWIZZLE_XYZW;
295
296 src_reg indirect_offset = get_indirect_offset(instr);
297 unsigned imm_offset = instr->const_index[0];
298
299 unsigned first_component = nir_intrinsic_component(instr);
300 if (first_component) {
301 assert(swiz == BRW_SWIZZLE_XYZW);
302 swiz = BRW_SWZ_COMP_OUTPUT(first_component);
303 mask = mask << first_component;
304 }
305
306 emit_urb_write(swizzle(value, swiz), mask,
307 imm_offset, indirect_offset);
308 break;
309 }
310
311 case nir_intrinsic_control_barrier: {
312 dst_reg header = dst_reg(this, glsl_type::uvec4_type);
313 emit(TCS_OPCODE_CREATE_BARRIER_HEADER, header);
314 emit(SHADER_OPCODE_BARRIER, dst_null_ud(), src_reg(header));
315 break;
316 }
317
318 case nir_intrinsic_memory_barrier_tcs_patch:
319 break;
320
321 default:
322 vec4_visitor::nir_emit_intrinsic(instr);
323 }
324 }
325
326 /**
327 * Return the number of patches to accumulate before an 8_PATCH mode thread is
328 * launched. In cases with a large number of input control points and a large
329 * amount of VS outputs, the VS URB space needed to store an entire 8 patches
330 * worth of data can be prohibitive, so it can be beneficial to launch threads
331 * early.
332 *
333 * See the 3DSTATE_HS::Patch Count Threshold documentation for the recommended
334 * values. Note that 0 means to "disable" early dispatch, meaning to wait for
335 * a full 8 patches as normal.
336 */
337 static int
get_patch_count_threshold(int input_control_points)338 get_patch_count_threshold(int input_control_points)
339 {
340 if (input_control_points <= 4)
341 return 0;
342 else if (input_control_points <= 6)
343 return 5;
344 else if (input_control_points <= 8)
345 return 4;
346 else if (input_control_points <= 10)
347 return 3;
348 else if (input_control_points <= 14)
349 return 2;
350
351 /* Return patch count 1 for PATCHLIST_15 - PATCHLIST_32 */
352 return 1;
353 }
354
355 } /* namespace brw */
356
357 extern "C" const unsigned *
brw_compile_tcs(const struct brw_compiler * compiler,void * log_data,void * mem_ctx,const struct brw_tcs_prog_key * key,struct brw_tcs_prog_data * prog_data,nir_shader * nir,int shader_time_index,struct brw_compile_stats * stats,char ** error_str)358 brw_compile_tcs(const struct brw_compiler *compiler,
359 void *log_data,
360 void *mem_ctx,
361 const struct brw_tcs_prog_key *key,
362 struct brw_tcs_prog_data *prog_data,
363 nir_shader *nir,
364 int shader_time_index,
365 struct brw_compile_stats *stats,
366 char **error_str)
367 {
368 const struct gen_device_info *devinfo = compiler->devinfo;
369 struct brw_vue_prog_data *vue_prog_data = &prog_data->base;
370 const bool is_scalar = compiler->scalar_stage[MESA_SHADER_TESS_CTRL];
371 const unsigned *assembly;
372
373 nir->info.outputs_written = key->outputs_written;
374 nir->info.patch_outputs_written = key->patch_outputs_written;
375
376 struct brw_vue_map input_vue_map;
377 brw_compute_vue_map(devinfo, &input_vue_map, nir->info.inputs_read,
378 nir->info.separate_shader, 1);
379 brw_compute_tess_vue_map(&vue_prog_data->vue_map,
380 nir->info.outputs_written,
381 nir->info.patch_outputs_written);
382
383 brw_nir_apply_key(nir, compiler, &key->base, 8, is_scalar);
384 brw_nir_lower_vue_inputs(nir, &input_vue_map);
385 brw_nir_lower_tcs_outputs(nir, &vue_prog_data->vue_map,
386 key->tes_primitive_mode);
387 if (key->quads_workaround)
388 brw_nir_apply_tcs_quads_workaround(nir);
389
390 brw_postprocess_nir(nir, compiler, is_scalar);
391
392 bool has_primitive_id =
393 BITSET_TEST(nir->info.system_values_read, SYSTEM_VALUE_PRIMITIVE_ID);
394
395 prog_data->patch_count_threshold = brw::get_patch_count_threshold(key->input_vertices);
396
397 if (compiler->use_tcs_8_patch &&
398 nir->info.tess.tcs_vertices_out <= (devinfo->gen >= 12 ? 32 : 16) &&
399 2 + has_primitive_id + key->input_vertices <= (devinfo->gen >= 12 ? 63 : 31)) {
400 /* 3DSTATE_HS imposes two constraints on using 8_PATCH mode. First, the
401 * "Instance" field limits the number of output vertices to [1, 16] on
402 * gen11 and below, or [1, 32] on gen12 and above. Secondly, the
403 * "Dispatch GRF Start Register for URB Data" field is limited to [0,
404 * 31] - which imposes a limit on the input vertices.
405 */
406 vue_prog_data->dispatch_mode = DISPATCH_MODE_TCS_8_PATCH;
407 prog_data->instances = nir->info.tess.tcs_vertices_out;
408 prog_data->include_primitive_id = has_primitive_id;
409 } else {
410 unsigned verts_per_thread = is_scalar ? 8 : 2;
411 vue_prog_data->dispatch_mode = DISPATCH_MODE_TCS_SINGLE_PATCH;
412 prog_data->instances =
413 DIV_ROUND_UP(nir->info.tess.tcs_vertices_out, verts_per_thread);
414 }
415
416 /* Compute URB entry size. The maximum allowed URB entry size is 32k.
417 * That divides up as follows:
418 *
419 * 32 bytes for the patch header (tessellation factors)
420 * 480 bytes for per-patch varyings (a varying component is 4 bytes and
421 * gl_MaxTessPatchComponents = 120)
422 * 16384 bytes for per-vertex varyings (a varying component is 4 bytes,
423 * gl_MaxPatchVertices = 32 and
424 * gl_MaxTessControlOutputComponents = 128)
425 *
426 * 15808 bytes left for varying packing overhead
427 */
428 const int num_per_patch_slots = vue_prog_data->vue_map.num_per_patch_slots;
429 const int num_per_vertex_slots = vue_prog_data->vue_map.num_per_vertex_slots;
430 unsigned output_size_bytes = 0;
431 /* Note that the patch header is counted in num_per_patch_slots. */
432 output_size_bytes += num_per_patch_slots * 16;
433 output_size_bytes += nir->info.tess.tcs_vertices_out *
434 num_per_vertex_slots * 16;
435
436 assert(output_size_bytes >= 1);
437 if (output_size_bytes > GEN7_MAX_HS_URB_ENTRY_SIZE_BYTES)
438 return NULL;
439
440 /* URB entry sizes are stored as a multiple of 64 bytes. */
441 vue_prog_data->urb_entry_size = ALIGN(output_size_bytes, 64) / 64;
442
443 /* HS does not use the usual payload pushing from URB to GRFs,
444 * because we don't have enough registers for a full-size payload, and
445 * the hardware is broken on Haswell anyway.
446 */
447 vue_prog_data->urb_read_length = 0;
448
449 if (INTEL_DEBUG & DEBUG_TCS) {
450 fprintf(stderr, "TCS Input ");
451 brw_print_vue_map(stderr, &input_vue_map);
452 fprintf(stderr, "TCS Output ");
453 brw_print_vue_map(stderr, &vue_prog_data->vue_map);
454 }
455
456 if (is_scalar) {
457 fs_visitor v(compiler, log_data, mem_ctx, &key->base,
458 &prog_data->base.base, nir, 8,
459 shader_time_index, &input_vue_map);
460 if (!v.run_tcs()) {
461 if (error_str)
462 *error_str = ralloc_strdup(mem_ctx, v.fail_msg);
463 return NULL;
464 }
465
466 prog_data->base.base.dispatch_grf_start_reg = v.payload.num_regs;
467
468 fs_generator g(compiler, log_data, mem_ctx,
469 &prog_data->base.base, false, MESA_SHADER_TESS_CTRL);
470 if (INTEL_DEBUG & DEBUG_TCS) {
471 g.enable_debug(ralloc_asprintf(mem_ctx,
472 "%s tessellation control shader %s",
473 nir->info.label ? nir->info.label
474 : "unnamed",
475 nir->info.name));
476 }
477
478 g.generate_code(v.cfg, 8, v.shader_stats,
479 v.performance_analysis.require(), stats);
480
481 g.add_const_data(nir->constant_data, nir->constant_data_size);
482
483 assembly = g.get_assembly();
484 } else {
485 brw::vec4_tcs_visitor v(compiler, log_data, key, prog_data,
486 nir, mem_ctx, shader_time_index, &input_vue_map);
487 if (!v.run()) {
488 if (error_str)
489 *error_str = ralloc_strdup(mem_ctx, v.fail_msg);
490 return NULL;
491 }
492
493 if (INTEL_DEBUG & DEBUG_TCS)
494 v.dump_instructions();
495
496
497 assembly = brw_vec4_generate_assembly(compiler, log_data, mem_ctx, nir,
498 &prog_data->base, v.cfg,
499 v.performance_analysis.require(),
500 stats);
501 }
502
503 return assembly;
504 }
505