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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 "common/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->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 (unlikely(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       src_reg indirect_offset = get_indirect_offset(instr);
261       unsigned imm_offset = instr->const_index[0];
262 
263       nir_const_value *vertex_const = nir_src_as_const_value(instr->src[0]);
264       src_reg vertex_index =
265          vertex_const ? src_reg(brw_imm_ud(vertex_const->u32[0]))
266                       : get_nir_src(instr->src[0], BRW_REGISTER_TYPE_UD, 1);
267 
268       unsigned first_component = nir_intrinsic_component(instr);
269       if (nir_dest_bit_size(instr->dest) == 64) {
270          /* We need to emit up to two 32-bit URB reads, then shuffle
271           * the result into a temporary, then move to the destination
272           * honoring the writemask
273           *
274           * We don't need to divide first_component by 2 because
275           * emit_input_urb_read takes a 32-bit type.
276           */
277          dst_reg tmp = dst_reg(this, glsl_type::dvec4_type);
278          dst_reg tmp_d = retype(tmp, BRW_REGISTER_TYPE_D);
279          emit_input_urb_read(tmp_d, vertex_index, imm_offset,
280                              first_component, indirect_offset);
281          if (instr->num_components > 2) {
282             emit_input_urb_read(byte_offset(tmp_d, REG_SIZE), vertex_index,
283                                 imm_offset + 1, 0, indirect_offset);
284          }
285 
286          src_reg tmp_src = retype(src_reg(tmp_d), BRW_REGISTER_TYPE_DF);
287          dst_reg shuffled = dst_reg(this, glsl_type::dvec4_type);
288          shuffle_64bit_data(shuffled, tmp_src, false);
289 
290          dst_reg dst = get_nir_dest(instr->dest, BRW_REGISTER_TYPE_DF);
291          dst.writemask = brw_writemask_for_size(instr->num_components);
292          emit(MOV(dst, src_reg(shuffled)));
293       } else {
294          dst_reg dst = get_nir_dest(instr->dest, BRW_REGISTER_TYPE_D);
295          dst.writemask = brw_writemask_for_size(instr->num_components);
296          emit_input_urb_read(dst, vertex_index, imm_offset,
297                              first_component, indirect_offset);
298       }
299       break;
300    }
301    case nir_intrinsic_load_input:
302       unreachable("nir_lower_io should use load_per_vertex_input intrinsics");
303       break;
304    case nir_intrinsic_load_output:
305    case nir_intrinsic_load_per_vertex_output: {
306       src_reg indirect_offset = get_indirect_offset(instr);
307       unsigned imm_offset = instr->const_index[0];
308 
309       dst_reg dst = get_nir_dest(instr->dest, BRW_REGISTER_TYPE_D);
310       dst.writemask = brw_writemask_for_size(instr->num_components);
311 
312       emit_output_urb_read(dst, imm_offset, nir_intrinsic_component(instr),
313                            indirect_offset);
314       break;
315    }
316    case nir_intrinsic_store_output:
317    case nir_intrinsic_store_per_vertex_output: {
318       src_reg value = get_nir_src(instr->src[0]);
319       unsigned mask = instr->const_index[1];
320       unsigned swiz = BRW_SWIZZLE_XYZW;
321 
322       src_reg indirect_offset = get_indirect_offset(instr);
323       unsigned imm_offset = instr->const_index[0];
324 
325       unsigned first_component = nir_intrinsic_component(instr);
326       if (first_component) {
327          if (nir_src_bit_size(instr->src[0]) == 64)
328             first_component /= 2;
329          assert(swiz == BRW_SWIZZLE_XYZW);
330          swiz = BRW_SWZ_COMP_OUTPUT(first_component);
331          mask = mask << first_component;
332       }
333 
334       if (nir_src_bit_size(instr->src[0]) == 64) {
335          /* For 64-bit data we need to shuffle the data before we write and
336           * emit two messages. Also, since each channel is twice as large we
337           * need to fix the writemask in each 32-bit message to account for it.
338           */
339          value = swizzle(retype(value, BRW_REGISTER_TYPE_DF), swiz);
340          dst_reg shuffled = dst_reg(this, glsl_type::dvec4_type);
341          shuffle_64bit_data(shuffled, value, true);
342          src_reg shuffled_float = src_reg(retype(shuffled, BRW_REGISTER_TYPE_F));
343 
344          for (int n = 0; n < 2; n++) {
345             unsigned fixed_mask = 0;
346             if (mask & WRITEMASK_X)
347                fixed_mask |= WRITEMASK_XY;
348             if (mask & WRITEMASK_Y)
349                fixed_mask |= WRITEMASK_ZW;
350             emit_urb_write(shuffled_float, fixed_mask,
351                            imm_offset, indirect_offset);
352 
353             shuffled_float = byte_offset(shuffled_float, REG_SIZE);
354             mask >>= 2;
355             imm_offset++;
356          }
357       } else {
358          emit_urb_write(swizzle(value, swiz), mask,
359                         imm_offset, indirect_offset);
360       }
361       break;
362    }
363 
364    case nir_intrinsic_barrier: {
365       dst_reg header = dst_reg(this, glsl_type::uvec4_type);
366       emit(TCS_OPCODE_CREATE_BARRIER_HEADER, header);
367       emit(SHADER_OPCODE_BARRIER, dst_null_ud(), src_reg(header));
368       break;
369    }
370 
371    default:
372       vec4_visitor::nir_emit_intrinsic(instr);
373    }
374 }
375 
376 
377 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,const nir_shader * src_shader,int shader_time_index,char ** error_str)378 brw_compile_tcs(const struct brw_compiler *compiler,
379                 void *log_data,
380                 void *mem_ctx,
381                 const struct brw_tcs_prog_key *key,
382                 struct brw_tcs_prog_data *prog_data,
383                 const nir_shader *src_shader,
384                 int shader_time_index,
385                 char **error_str)
386 {
387    const struct gen_device_info *devinfo = compiler->devinfo;
388    struct brw_vue_prog_data *vue_prog_data = &prog_data->base;
389    const bool is_scalar = compiler->scalar_stage[MESA_SHADER_TESS_CTRL];
390    const unsigned *assembly;
391 
392    nir_shader *nir = nir_shader_clone(mem_ctx, src_shader);
393    nir->info.outputs_written = key->outputs_written;
394    nir->info.patch_outputs_written = key->patch_outputs_written;
395 
396    struct brw_vue_map input_vue_map;
397    brw_compute_vue_map(devinfo, &input_vue_map, nir->info.inputs_read,
398                        nir->info.separate_shader);
399    brw_compute_tess_vue_map(&vue_prog_data->vue_map,
400                             nir->info.outputs_written,
401                             nir->info.patch_outputs_written);
402 
403    nir = brw_nir_apply_sampler_key(nir, compiler, &key->tex, is_scalar);
404    brw_nir_lower_vue_inputs(nir, &input_vue_map);
405    brw_nir_lower_tcs_outputs(nir, &vue_prog_data->vue_map,
406                              key->tes_primitive_mode);
407    if (key->quads_workaround)
408       brw_nir_apply_tcs_quads_workaround(nir);
409 
410    nir = brw_postprocess_nir(nir, compiler, is_scalar);
411 
412    if (is_scalar)
413       prog_data->instances = DIV_ROUND_UP(nir->info.tess.tcs_vertices_out, 8);
414    else
415       prog_data->instances = DIV_ROUND_UP(nir->info.tess.tcs_vertices_out, 2);
416 
417    /* Compute URB entry size.  The maximum allowed URB entry size is 32k.
418     * That divides up as follows:
419     *
420     *     32 bytes for the patch header (tessellation factors)
421     *    480 bytes for per-patch varyings (a varying component is 4 bytes and
422     *              gl_MaxTessPatchComponents = 120)
423     *  16384 bytes for per-vertex varyings (a varying component is 4 bytes,
424     *              gl_MaxPatchVertices = 32 and
425     *              gl_MaxTessControlOutputComponents = 128)
426     *
427     *  15808 bytes left for varying packing overhead
428     */
429    const int num_per_patch_slots = vue_prog_data->vue_map.num_per_patch_slots;
430    const int num_per_vertex_slots = vue_prog_data->vue_map.num_per_vertex_slots;
431    unsigned output_size_bytes = 0;
432    /* Note that the patch header is counted in num_per_patch_slots. */
433    output_size_bytes += num_per_patch_slots * 16;
434    output_size_bytes += nir->info.tess.tcs_vertices_out *
435                         num_per_vertex_slots * 16;
436 
437    assert(output_size_bytes >= 1);
438    if (output_size_bytes > GEN7_MAX_HS_URB_ENTRY_SIZE_BYTES)
439       return NULL;
440 
441    /* URB entry sizes are stored as a multiple of 64 bytes. */
442    vue_prog_data->urb_entry_size = ALIGN(output_size_bytes, 64) / 64;
443 
444    /* On Cannonlake software shall not program an allocation size that
445     * specifies a size that is a multiple of 3 64B (512-bit) cachelines.
446     */
447    if (devinfo->gen == 10 &&
448        vue_prog_data->urb_entry_size % 3 == 0)
449       vue_prog_data->urb_entry_size++;
450 
451    /* HS does not use the usual payload pushing from URB to GRFs,
452     * because we don't have enough registers for a full-size payload, and
453     * the hardware is broken on Haswell anyway.
454     */
455    vue_prog_data->urb_read_length = 0;
456 
457    if (unlikely(INTEL_DEBUG & DEBUG_TCS)) {
458       fprintf(stderr, "TCS Input ");
459       brw_print_vue_map(stderr, &input_vue_map);
460       fprintf(stderr, "TCS Output ");
461       brw_print_vue_map(stderr, &vue_prog_data->vue_map);
462    }
463 
464    if (is_scalar) {
465       fs_visitor v(compiler, log_data, mem_ctx, (void *) key,
466                    &prog_data->base.base, NULL, nir, 8,
467                    shader_time_index, &input_vue_map);
468       if (!v.run_tcs_single_patch()) {
469          if (error_str)
470             *error_str = ralloc_strdup(mem_ctx, v.fail_msg);
471          return NULL;
472       }
473 
474       prog_data->base.base.dispatch_grf_start_reg = v.payload.num_regs;
475       prog_data->base.dispatch_mode = DISPATCH_MODE_SIMD8;
476 
477       fs_generator g(compiler, log_data, mem_ctx, (void *) key,
478                      &prog_data->base.base, v.promoted_constants, false,
479                      MESA_SHADER_TESS_CTRL);
480       if (unlikely(INTEL_DEBUG & DEBUG_TCS)) {
481          g.enable_debug(ralloc_asprintf(mem_ctx,
482                                         "%s tessellation control shader %s",
483                                         nir->info.label ? nir->info.label
484                                                         : "unnamed",
485                                         nir->info.name));
486       }
487 
488       g.generate_code(v.cfg, 8);
489 
490       assembly = g.get_assembly(&prog_data->base.base.program_size);
491    } else {
492       vec4_tcs_visitor v(compiler, log_data, key, prog_data,
493                          nir, mem_ctx, shader_time_index, &input_vue_map);
494       if (!v.run()) {
495          if (error_str)
496             *error_str = ralloc_strdup(mem_ctx, v.fail_msg);
497          return NULL;
498       }
499 
500       if (unlikely(INTEL_DEBUG & DEBUG_TCS))
501          v.dump_instructions();
502 
503 
504       assembly = brw_vec4_generate_assembly(compiler, log_data, mem_ctx, nir,
505                                             &prog_data->base, v.cfg,
506                                             &prog_data->base.base.program_size);
507    }
508 
509    return assembly;
510 }
511 
512 
513 } /* namespace brw */
514