1 /*
2  * Copyright © 2015 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 DEALINGS
21  * IN THE SOFTWARE.
22  */
23 
24 #include "brw_context.h"
25 #include "compiler/brw_nir.h"
26 #include "brw_program.h"
27 #include "compiler/glsl/gl_nir.h"
28 #include "compiler/glsl/gl_nir_linker.h"
29 #include "compiler/glsl/ir.h"
30 #include "compiler/glsl/ir_optimization.h"
31 #include "compiler/glsl/program.h"
32 #include "compiler/nir/nir_serialize.h"
33 #include "program/program.h"
34 #include "main/glspirv.h"
35 #include "main/mtypes.h"
36 #include "main/shaderapi.h"
37 #include "main/shaderobj.h"
38 #include "main/uniforms.h"
39 
40 /**
41  * Performs a compile of the shader stages even when we don't know
42  * what non-orthogonal state will be set, in the hope that it reflects
43  * the eventual NOS used, and thus allows us to produce link failures.
44  */
45 static bool
brw_shader_precompile(struct gl_context * ctx,struct gl_shader_program * sh_prog)46 brw_shader_precompile(struct gl_context *ctx,
47                       struct gl_shader_program *sh_prog)
48 {
49    struct gl_linked_shader *vs = sh_prog->_LinkedShaders[MESA_SHADER_VERTEX];
50    struct gl_linked_shader *tcs = sh_prog->_LinkedShaders[MESA_SHADER_TESS_CTRL];
51    struct gl_linked_shader *tes = sh_prog->_LinkedShaders[MESA_SHADER_TESS_EVAL];
52    struct gl_linked_shader *gs = sh_prog->_LinkedShaders[MESA_SHADER_GEOMETRY];
53    struct gl_linked_shader *fs = sh_prog->_LinkedShaders[MESA_SHADER_FRAGMENT];
54    struct gl_linked_shader *cs = sh_prog->_LinkedShaders[MESA_SHADER_COMPUTE];
55 
56    if (fs && !brw_fs_precompile(ctx, fs->Program))
57       return false;
58 
59    if (gs && !brw_gs_precompile(ctx, gs->Program))
60       return false;
61 
62    if (tes && !brw_tes_precompile(ctx, sh_prog, tes->Program))
63       return false;
64 
65    if (tcs && !brw_tcs_precompile(ctx, sh_prog, tcs->Program))
66       return false;
67 
68    if (vs && !brw_vs_precompile(ctx, vs->Program))
69       return false;
70 
71    if (cs && !brw_cs_precompile(ctx, cs->Program))
72       return false;
73 
74    return true;
75 }
76 
77 static void
brw_lower_packing_builtins(struct brw_context * brw,exec_list * ir)78 brw_lower_packing_builtins(struct brw_context *brw,
79                            exec_list *ir)
80 {
81    const struct gen_device_info *devinfo = &brw->screen->devinfo;
82 
83    /* Gens < 7 don't have instructions to convert to or from half-precision,
84     * and Gens < 6 don't expose that functionality.
85     */
86    if (devinfo->gen != 6)
87       return;
88 
89    lower_packing_builtins(ir, LOWER_PACK_HALF_2x16 | LOWER_UNPACK_HALF_2x16);
90 }
91 
92 static void
process_glsl_ir(struct brw_context * brw,struct gl_shader_program * shader_prog,struct gl_linked_shader * shader)93 process_glsl_ir(struct brw_context *brw,
94                 struct gl_shader_program *shader_prog,
95                 struct gl_linked_shader *shader)
96 {
97    const struct gen_device_info *devinfo = &brw->screen->devinfo;
98    struct gl_context *ctx = &brw->ctx;
99 
100    /* Temporary memory context for any new IR. */
101    void *mem_ctx = ralloc_context(NULL);
102 
103    ralloc_adopt(mem_ctx, shader->ir);
104 
105    lower_blend_equation_advanced(
106       shader, ctx->Extensions.KHR_blend_equation_advanced_coherent);
107 
108    /* lower_packing_builtins() inserts arithmetic instructions, so it
109     * must precede lower_instructions().
110     */
111    brw_lower_packing_builtins(brw, shader->ir);
112    do_mat_op_to_vec(shader->ir);
113 
114    unsigned instructions_to_lower = (DIV_TO_MUL_RCP |
115                                      SUB_TO_ADD_NEG |
116                                      EXP_TO_EXP2 |
117                                      LOG_TO_LOG2 |
118                                      DFREXP_DLDEXP_TO_ARITH);
119    if (devinfo->gen < 7) {
120       instructions_to_lower |= BIT_COUNT_TO_MATH |
121                                EXTRACT_TO_SHIFTS |
122                                INSERT_TO_SHIFTS |
123                                REVERSE_TO_SHIFTS;
124    }
125 
126    lower_instructions(shader->ir, instructions_to_lower);
127 
128    /* Pre-gen6 HW can only nest if-statements 16 deep.  Beyond this,
129     * if-statements need to be flattened.
130     */
131    if (devinfo->gen < 6)
132       lower_if_to_cond_assign(shader->Stage, shader->ir, 16);
133 
134    do_lower_texture_projection(shader->ir);
135    do_vec_index_to_cond_assign(shader->ir);
136    lower_vector_insert(shader->ir, true);
137    lower_offset_arrays(shader->ir);
138    lower_quadop_vector(shader->ir, false);
139 
140    validate_ir_tree(shader->ir);
141 
142    /* Now that we've finished altering the linked IR, reparent any live IR back
143     * to the permanent memory context, and free the temporary one (discarding any
144     * junk we optimized away).
145     */
146    reparent_ir(shader->ir, shader->ir);
147    ralloc_free(mem_ctx);
148 
149    if (ctx->_Shader->Flags & GLSL_DUMP) {
150       fprintf(stderr, "\n");
151       if (shader->ir) {
152          fprintf(stderr, "GLSL IR for linked %s program %d:\n",
153                  _mesa_shader_stage_to_string(shader->Stage),
154                  shader_prog->Name);
155          _mesa_print_ir(stderr, shader->ir, NULL);
156       } else {
157          fprintf(stderr, "No GLSL IR for linked %s program %d (shader may be "
158                  "from cache)\n", _mesa_shader_stage_to_string(shader->Stage),
159                  shader_prog->Name);
160       }
161       fprintf(stderr, "\n");
162    }
163 }
164 
165 static void
unify_interfaces(struct shader_info ** infos)166 unify_interfaces(struct shader_info **infos)
167 {
168    struct shader_info *prev_info = NULL;
169 
170    for (unsigned i = MESA_SHADER_VERTEX; i < MESA_SHADER_FRAGMENT; i++) {
171       if (!infos[i])
172          continue;
173 
174       if (prev_info) {
175          prev_info->outputs_written |= infos[i]->inputs_read &
176             ~(VARYING_BIT_TESS_LEVEL_INNER | VARYING_BIT_TESS_LEVEL_OUTER);
177          infos[i]->inputs_read |= prev_info->outputs_written &
178             ~(VARYING_BIT_TESS_LEVEL_INNER | VARYING_BIT_TESS_LEVEL_OUTER);
179 
180          prev_info->patch_outputs_written |= infos[i]->patch_inputs_read;
181          infos[i]->patch_inputs_read |= prev_info->patch_outputs_written;
182       }
183       prev_info = infos[i];
184    }
185 }
186 
187 static void
update_xfb_info(struct gl_transform_feedback_info * xfb_info,struct shader_info * info)188 update_xfb_info(struct gl_transform_feedback_info *xfb_info,
189                 struct shader_info *info)
190 {
191    if (!xfb_info)
192       return;
193 
194    for (unsigned i = 0; i < xfb_info->NumOutputs; i++) {
195       struct gl_transform_feedback_output *output = &xfb_info->Outputs[i];
196 
197       /* The VUE header contains three scalar fields packed together:
198        * - gl_PointSize is stored in VARYING_SLOT_PSIZ.w
199        * - gl_Layer is stored in VARYING_SLOT_PSIZ.y
200        * - gl_ViewportIndex is stored in VARYING_SLOT_PSIZ.z
201        */
202       switch (output->OutputRegister) {
203       case VARYING_SLOT_LAYER:
204          assert(output->NumComponents == 1);
205          output->OutputRegister = VARYING_SLOT_PSIZ;
206          output->ComponentOffset = 1;
207          break;
208       case VARYING_SLOT_VIEWPORT:
209          assert(output->NumComponents == 1);
210          output->OutputRegister = VARYING_SLOT_PSIZ;
211          output->ComponentOffset = 2;
212          break;
213       case VARYING_SLOT_PSIZ:
214          assert(output->NumComponents == 1);
215          output->ComponentOffset = 3;
216          break;
217       }
218 
219       info->outputs_written |= 1ull << output->OutputRegister;
220    }
221 }
222 
223 extern "C" GLboolean
brw_link_shader(struct gl_context * ctx,struct gl_shader_program * shProg)224 brw_link_shader(struct gl_context *ctx, struct gl_shader_program *shProg)
225 {
226    struct brw_context *brw = brw_context(ctx);
227    const struct brw_compiler *compiler = brw->screen->compiler;
228    unsigned int stage;
229    struct shader_info *infos[MESA_SHADER_STAGES] = { 0, };
230 
231    if (shProg->data->LinkStatus == LINKING_SKIPPED)
232       return GL_TRUE;
233 
234    for (stage = 0; stage < ARRAY_SIZE(shProg->_LinkedShaders); stage++) {
235       struct gl_linked_shader *shader = shProg->_LinkedShaders[stage];
236       if (!shader)
237          continue;
238 
239       struct gl_program *prog = shader->Program;
240       prog->Parameters = _mesa_new_parameter_list();
241 
242       if (!shader->spirv_data)
243          process_glsl_ir(brw, shProg, shader);
244 
245       _mesa_copy_linked_program_data(shProg, shader);
246 
247       prog->ShadowSamplers = shader->shadow_samplers;
248 
249       bool debug_enabled =
250          (INTEL_DEBUG & intel_debug_flag_for_shader_stage(shader->Stage));
251 
252       if (debug_enabled && shader->ir) {
253          fprintf(stderr, "GLSL IR for native %s shader %d:\n",
254                  _mesa_shader_stage_to_string(shader->Stage), shProg->Name);
255          _mesa_print_ir(stderr, shader->ir, NULL);
256          fprintf(stderr, "\n\n");
257       }
258 
259       prog->nir = brw_create_nir(brw, shProg, prog, (gl_shader_stage) stage,
260                                  compiler->scalar_stage[stage]);
261    }
262 
263    /* TODO: Verify if its feasible to split up the NIR linking work into a
264     * per-stage part (that fill out information we need for the passes) and a
265     * actual linking part, so that we could fold back brw_nir_lower_resources
266     * back into brw_create_nir.
267     */
268 
269    /* SPIR-V programs use a NIR linker */
270    if (shProg->data->spirv) {
271       static const gl_nir_linker_options opts = {
272          .fill_parameters = false,
273       };
274       if (!gl_nir_link_spirv(ctx, shProg, &opts))
275          return GL_FALSE;
276    }
277 
278    for (stage = 0; stage < ARRAY_SIZE(shProg->_LinkedShaders); stage++) {
279       struct gl_linked_shader *shader = shProg->_LinkedShaders[stage];
280       if (!shader)
281          continue;
282 
283       struct gl_program *prog = shader->Program;
284 
285       brw_nir_lower_resources(prog->nir, shProg, prog, &brw->screen->devinfo);
286 
287       NIR_PASS_V(prog->nir, brw_nir_lower_gl_images, prog);
288    }
289 
290    /* Determine first and last stage. */
291    unsigned first = MESA_SHADER_STAGES;
292    unsigned last = 0;
293    for (unsigned i = 0; i < MESA_SHADER_STAGES; i++) {
294       if (!shProg->_LinkedShaders[i])
295          continue;
296       if (first == MESA_SHADER_STAGES)
297          first = i;
298       last = i;
299    }
300 
301    /* Linking the stages in the opposite order (from fragment to vertex)
302     * ensures that inter-shader outputs written to in an earlier stage
303     * are eliminated if they are (transitively) not used in a later
304     * stage.
305     *
306     * TODO: Look into Shadow of Mordor regressions on HSW and enable this for
307     * all platforms. See: https://bugs.freedesktop.org/show_bug.cgi?id=103537
308     */
309     if (first != last && brw->screen->devinfo.gen >= 8) {
310        int next = last;
311        for (int i = next - 1; i >= 0; i--) {
312           if (shProg->_LinkedShaders[i] == NULL)
313              continue;
314 
315           brw_nir_link_shaders(compiler,
316                                shProg->_LinkedShaders[i]->Program->nir,
317                                shProg->_LinkedShaders[next]->Program->nir);
318           next = i;
319        }
320     }
321 
322    for (stage = 0; stage < ARRAY_SIZE(shProg->_LinkedShaders); stage++) {
323       struct gl_linked_shader *shader = shProg->_LinkedShaders[stage];
324       if (!shader)
325          continue;
326 
327       struct gl_program *prog = shader->Program;
328 
329       _mesa_update_shader_textures_used(shProg, prog);
330 
331       brw_shader_gather_info(prog->nir, prog);
332 
333       NIR_PASS_V(prog->nir, gl_nir_lower_atomics, shProg, false);
334       NIR_PASS_V(prog->nir, nir_lower_atomics_to_ssbo);
335 
336       nir_sweep(prog->nir);
337 
338       infos[stage] = &prog->nir->info;
339 
340       update_xfb_info(prog->sh.LinkedTransformFeedback, infos[stage]);
341 
342       /* Make a pass over the IR to add state references for any built-in
343        * uniforms that are used.  This has to be done now (during linking).
344        * Code generation doesn't happen until the first time this shader is
345        * used for rendering.  Waiting until then to generate the parameters is
346        * too late.  At that point, the values for the built-in uniforms won't
347        * get sent to the shader.
348        */
349       nir_foreach_uniform_variable(var, prog->nir) {
350          const nir_state_slot *const slots = var->state_slots;
351          for (unsigned int i = 0; i < var->num_state_slots; i++) {
352             assert(slots != NULL);
353             _mesa_add_state_reference(prog->Parameters, slots[i].tokens);
354          }
355       }
356    }
357 
358    /* The linker tries to dead code eliminate unused varying components,
359     * and make sure interfaces match.  But it isn't able to do so in all
360     * cases.  So, explicitly make the interfaces match by OR'ing together
361     * the inputs_read/outputs_written bitfields of adjacent stages.
362     */
363    if (!shProg->SeparateShader)
364       unify_interfaces(infos);
365 
366    if ((ctx->_Shader->Flags & GLSL_DUMP) && shProg->Name != 0) {
367       for (unsigned i = 0; i < shProg->NumShaders; i++) {
368          const struct gl_shader *sh = shProg->Shaders[i];
369          if (!sh)
370             continue;
371 
372          fprintf(stderr, "GLSL %s shader %d source for linked program %d:\n",
373                  _mesa_shader_stage_to_string(sh->Stage),
374                  i, shProg->Name);
375          fprintf(stderr, "%s", sh->Source);
376          fprintf(stderr, "\n");
377       }
378    }
379 
380    if (brw->precompile && !brw_shader_precompile(ctx, shProg))
381       return GL_FALSE;
382 
383    /* SPIR-V programs build its resource list from linked NIR shaders. */
384    if (!shProg->data->spirv)
385       build_program_resource_list(ctx, shProg, false);
386    else
387       nir_build_program_resource_list(ctx, shProg, true);
388 
389    for (stage = 0; stage < ARRAY_SIZE(shProg->_LinkedShaders); stage++) {
390       struct gl_linked_shader *shader = shProg->_LinkedShaders[stage];
391       if (!shader)
392          continue;
393 
394       /* The GLSL IR won't be needed anymore. */
395       ralloc_free(shader->ir);
396       shader->ir = NULL;
397    }
398 
399    return GL_TRUE;
400 }
401