1/* 2 * Copyright © 2011 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 lower_varyings_to_packed.cpp 26 * 27 * This lowering pass generates GLSL code that manually packs varyings into 28 * vec4 slots, for the benefit of back-ends that don't support packed varyings 29 * natively. 30 * 31 * For example, the following shader: 32 * 33 * out mat3x2 foo; // location=4, location_frac=0 34 * out vec3 bar[2]; // location=5, location_frac=2 35 * 36 * main() 37 * { 38 * ... 39 * } 40 * 41 * Is rewritten to: 42 * 43 * mat3x2 foo; 44 * vec3 bar[2]; 45 * out vec4 packed4; // location=4, location_frac=0 46 * out vec4 packed5; // location=5, location_frac=0 47 * out vec4 packed6; // location=6, location_frac=0 48 * 49 * main() 50 * { 51 * ... 52 * packed4.xy = foo[0]; 53 * packed4.zw = foo[1]; 54 * packed5.xy = foo[2]; 55 * packed5.zw = bar[0].xy; 56 * packed6.x = bar[0].z; 57 * packed6.yzw = bar[1]; 58 * } 59 * 60 * This lowering pass properly handles "double parking" of a varying vector 61 * across two varying slots. For example, in the code above, two of the 62 * components of bar[0] are stored in packed5, and the remaining component is 63 * stored in packed6. 64 * 65 * Note that in theory, the extra instructions may cause some loss of 66 * performance. However, hopefully in most cases the performance loss will 67 * either be absorbed by a later optimization pass, or it will be offset by 68 * memory bandwidth savings (because fewer varyings are used). 69 * 70 * This lowering pass also packs flat floats, ints, and uints together, by 71 * using ivec4 as the base type of flat "varyings", and using appropriate 72 * casts to convert floats and uints into ints. 73 * 74 * This lowering pass also handles varyings whose type is a struct or an array 75 * of struct. Structs are packed in order and with no gaps, so there may be a 76 * performance penalty due to structure elements being double-parked. 77 * 78 * Lowering of geometry shader inputs is slightly more complex, since geometry 79 * inputs are always arrays, so we need to lower arrays to arrays. For 80 * example, the following input: 81 * 82 * in struct Foo { 83 * float f; 84 * vec3 v; 85 * vec2 a[2]; 86 * } arr[3]; // location=4, location_frac=0 87 * 88 * Would get lowered like this if it occurred in a fragment shader: 89 * 90 * struct Foo { 91 * float f; 92 * vec3 v; 93 * vec2 a[2]; 94 * } arr[3]; 95 * in vec4 packed4; // location=4, location_frac=0 96 * in vec4 packed5; // location=5, location_frac=0 97 * in vec4 packed6; // location=6, location_frac=0 98 * in vec4 packed7; // location=7, location_frac=0 99 * in vec4 packed8; // location=8, location_frac=0 100 * in vec4 packed9; // location=9, location_frac=0 101 * 102 * main() 103 * { 104 * arr[0].f = packed4.x; 105 * arr[0].v = packed4.yzw; 106 * arr[0].a[0] = packed5.xy; 107 * arr[0].a[1] = packed5.zw; 108 * arr[1].f = packed6.x; 109 * arr[1].v = packed6.yzw; 110 * arr[1].a[0] = packed7.xy; 111 * arr[1].a[1] = packed7.zw; 112 * arr[2].f = packed8.x; 113 * arr[2].v = packed8.yzw; 114 * arr[2].a[0] = packed9.xy; 115 * arr[2].a[1] = packed9.zw; 116 * ... 117 * } 118 * 119 * But it would get lowered like this if it occurred in a geometry shader: 120 * 121 * struct Foo { 122 * float f; 123 * vec3 v; 124 * vec2 a[2]; 125 * } arr[3]; 126 * in vec4 packed4[3]; // location=4, location_frac=0 127 * in vec4 packed5[3]; // location=5, location_frac=0 128 * 129 * main() 130 * { 131 * arr[0].f = packed4[0].x; 132 * arr[0].v = packed4[0].yzw; 133 * arr[0].a[0] = packed5[0].xy; 134 * arr[0].a[1] = packed5[0].zw; 135 * arr[1].f = packed4[1].x; 136 * arr[1].v = packed4[1].yzw; 137 * arr[1].a[0] = packed5[1].xy; 138 * arr[1].a[1] = packed5[1].zw; 139 * arr[2].f = packed4[2].x; 140 * arr[2].v = packed4[2].yzw; 141 * arr[2].a[0] = packed5[2].xy; 142 * arr[2].a[1] = packed5[2].zw; 143 * ... 144 * } 145 */ 146 147#include "glsl_symbol_table.h" 148#include "ir.h" 149#include "ir_builder.h" 150#include "ir_optimization.h" 151#include "program/prog_instruction.h" 152#include "main/mtypes.h" 153 154using namespace ir_builder; 155 156namespace { 157 158/** 159 * Visitor that performs varying packing. For each varying declared in the 160 * shader, this visitor determines whether it needs to be packed. If so, it 161 * demotes it to an ordinary global, creates new packed varyings, and 162 * generates assignments to convert between the original varying and the 163 * packed varying. 164 */ 165class lower_packed_varyings_visitor 166{ 167public: 168 lower_packed_varyings_visitor(void *mem_ctx, 169 unsigned locations_used, 170 const uint8_t *components, 171 ir_variable_mode mode, 172 unsigned gs_input_vertices, 173 exec_list *out_instructions, 174 exec_list *out_variables, 175 bool disable_varying_packing, 176 bool xfb_enabled); 177 178 void run(struct gl_linked_shader *shader); 179 180private: 181 void bitwise_assign_pack(ir_rvalue *lhs, ir_rvalue *rhs); 182 void bitwise_assign_unpack(ir_rvalue *lhs, ir_rvalue *rhs); 183 unsigned lower_rvalue(ir_rvalue *rvalue, unsigned fine_location, 184 ir_variable *unpacked_var, const char *name, 185 bool gs_input_toplevel, unsigned vertex_index); 186 unsigned lower_arraylike(ir_rvalue *rvalue, unsigned array_size, 187 unsigned fine_location, 188 ir_variable *unpacked_var, const char *name, 189 bool gs_input_toplevel, unsigned vertex_index); 190 ir_dereference *get_packed_varying_deref(unsigned location, 191 ir_variable *unpacked_var, 192 const char *name, 193 unsigned vertex_index); 194 bool needs_lowering(ir_variable *var); 195 196 /** 197 * Memory context used to allocate new instructions for the shader. 198 */ 199 void * const mem_ctx; 200 201 /** 202 * Number of generic varying slots which are used by this shader. This is 203 * used to allocate temporary intermediate data structures. If any varying 204 * used by this shader has a location greater than or equal to 205 * VARYING_SLOT_VAR0 + locations_used, an assertion will fire. 206 */ 207 const unsigned locations_used; 208 209 const uint8_t* components; 210 211 /** 212 * Array of pointers to the packed varyings that have been created for each 213 * generic varying slot. NULL entries in this array indicate varying slots 214 * for which a packed varying has not been created yet. 215 */ 216 ir_variable **packed_varyings; 217 218 /** 219 * Type of varying which is being lowered in this pass (either 220 * ir_var_shader_in or ir_var_shader_out). 221 */ 222 const ir_variable_mode mode; 223 224 /** 225 * If we are currently lowering geometry shader inputs, the number of input 226 * vertices the geometry shader accepts. Otherwise zero. 227 */ 228 const unsigned gs_input_vertices; 229 230 /** 231 * Exec list into which the visitor should insert the packing instructions. 232 * Caller provides this list; it should insert the instructions into the 233 * appropriate place in the shader once the visitor has finished running. 234 */ 235 exec_list *out_instructions; 236 237 /** 238 * Exec list into which the visitor should insert any new variables. 239 */ 240 exec_list *out_variables; 241 242 bool disable_varying_packing; 243 bool xfb_enabled; 244}; 245 246} /* anonymous namespace */ 247 248lower_packed_varyings_visitor::lower_packed_varyings_visitor( 249 void *mem_ctx, unsigned locations_used, const uint8_t *components, 250 ir_variable_mode mode, 251 unsigned gs_input_vertices, exec_list *out_instructions, 252 exec_list *out_variables, bool disable_varying_packing, 253 bool xfb_enabled) 254 : mem_ctx(mem_ctx), 255 locations_used(locations_used), 256 components(components), 257 packed_varyings((ir_variable **) 258 rzalloc_array_size(mem_ctx, sizeof(*packed_varyings), 259 locations_used)), 260 mode(mode), 261 gs_input_vertices(gs_input_vertices), 262 out_instructions(out_instructions), 263 out_variables(out_variables), 264 disable_varying_packing(disable_varying_packing), 265 xfb_enabled(xfb_enabled) 266{ 267} 268 269void 270lower_packed_varyings_visitor::run(struct gl_linked_shader *shader) 271{ 272 foreach_in_list(ir_instruction, node, shader->ir) { 273 ir_variable *var = node->as_variable(); 274 if (var == NULL) 275 continue; 276 277 if (var->data.mode != this->mode || 278 var->data.location < VARYING_SLOT_VAR0 || 279 !this->needs_lowering(var)) 280 continue; 281 282 /* This lowering pass is only capable of packing floats and ints 283 * together when their interpolation mode is "flat". Treat integers as 284 * being flat when the interpolation mode is none. 285 */ 286 assert(var->data.interpolation == INTERP_MODE_FLAT || 287 var->data.interpolation == INTERP_MODE_NONE || 288 !var->type->contains_integer()); 289 290 /* Clone the variable for program resource list before 291 * it gets modified and lost. 292 */ 293 if (!shader->packed_varyings) 294 shader->packed_varyings = new (shader) exec_list; 295 296 shader->packed_varyings->push_tail(var->clone(shader, NULL)); 297 298 /* Change the old varying into an ordinary global. */ 299 assert(var->data.mode != ir_var_temporary); 300 var->data.mode = ir_var_auto; 301 302 /* Create a reference to the old varying. */ 303 ir_dereference_variable *deref 304 = new(this->mem_ctx) ir_dereference_variable(var); 305 306 /* Recursively pack or unpack it. */ 307 this->lower_rvalue(deref, var->data.location * 4 + var->data.location_frac, var, 308 var->name, this->gs_input_vertices != 0, 0); 309 } 310} 311 312#define SWIZZLE_ZWZW MAKE_SWIZZLE4(SWIZZLE_Z, SWIZZLE_W, SWIZZLE_Z, SWIZZLE_W) 313 314/** 315 * Make an ir_assignment from \c rhs to \c lhs, performing appropriate 316 * bitcasts if necessary to match up types. 317 * 318 * This function is called when packing varyings. 319 */ 320void 321lower_packed_varyings_visitor::bitwise_assign_pack(ir_rvalue *lhs, 322 ir_rvalue *rhs) 323{ 324 if (lhs->type->base_type != rhs->type->base_type) { 325 /* Since we only mix types in flat varyings, and we always store flat 326 * varyings as type ivec4, we need only produce conversions from (uint 327 * or float) to int. 328 */ 329 assert(lhs->type->base_type == GLSL_TYPE_INT); 330 switch (rhs->type->base_type) { 331 case GLSL_TYPE_UINT: 332 rhs = new(this->mem_ctx) 333 ir_expression(ir_unop_u2i, lhs->type, rhs); 334 break; 335 case GLSL_TYPE_FLOAT: 336 rhs = new(this->mem_ctx) 337 ir_expression(ir_unop_bitcast_f2i, lhs->type, rhs); 338 break; 339 case GLSL_TYPE_DOUBLE: 340 assert(rhs->type->vector_elements <= 2); 341 if (rhs->type->vector_elements == 2) { 342 ir_variable *t = new(mem_ctx) ir_variable(lhs->type, "pack", ir_var_temporary); 343 344 assert(lhs->type->vector_elements == 4); 345 this->out_variables->push_tail(t); 346 this->out_instructions->push_tail( 347 assign(t, u2i(expr(ir_unop_unpack_double_2x32, swizzle_x(rhs->clone(mem_ctx, NULL)))), 0x3)); 348 this->out_instructions->push_tail( 349 assign(t, u2i(expr(ir_unop_unpack_double_2x32, swizzle_y(rhs))), 0xc)); 350 rhs = deref(t).val; 351 } else { 352 rhs = u2i(expr(ir_unop_unpack_double_2x32, rhs)); 353 } 354 break; 355 case GLSL_TYPE_INT64: 356 assert(rhs->type->vector_elements <= 2); 357 if (rhs->type->vector_elements == 2) { 358 ir_variable *t = new(mem_ctx) ir_variable(lhs->type, "pack", ir_var_temporary); 359 360 assert(lhs->type->vector_elements == 4); 361 this->out_variables->push_tail(t); 362 this->out_instructions->push_tail( 363 assign(t, expr(ir_unop_unpack_int_2x32, swizzle_x(rhs->clone(mem_ctx, NULL))), 0x3)); 364 this->out_instructions->push_tail( 365 assign(t, expr(ir_unop_unpack_int_2x32, swizzle_y(rhs)), 0xc)); 366 rhs = deref(t).val; 367 } else { 368 rhs = expr(ir_unop_unpack_int_2x32, rhs); 369 } 370 break; 371 case GLSL_TYPE_UINT64: 372 assert(rhs->type->vector_elements <= 2); 373 if (rhs->type->vector_elements == 2) { 374 ir_variable *t = new(mem_ctx) ir_variable(lhs->type, "pack", ir_var_temporary); 375 376 assert(lhs->type->vector_elements == 4); 377 this->out_variables->push_tail(t); 378 this->out_instructions->push_tail( 379 assign(t, u2i(expr(ir_unop_unpack_uint_2x32, swizzle_x(rhs->clone(mem_ctx, NULL)))), 0x3)); 380 this->out_instructions->push_tail( 381 assign(t, u2i(expr(ir_unop_unpack_uint_2x32, swizzle_y(rhs))), 0xc)); 382 rhs = deref(t).val; 383 } else { 384 rhs = u2i(expr(ir_unop_unpack_uint_2x32, rhs)); 385 } 386 break; 387 case GLSL_TYPE_SAMPLER: 388 rhs = u2i(expr(ir_unop_unpack_sampler_2x32, rhs)); 389 break; 390 case GLSL_TYPE_IMAGE: 391 rhs = u2i(expr(ir_unop_unpack_image_2x32, rhs)); 392 break; 393 default: 394 assert(!"Unexpected type conversion while lowering varyings"); 395 break; 396 } 397 } 398 this->out_instructions->push_tail(new (this->mem_ctx) ir_assignment(lhs, rhs)); 399} 400 401 402/** 403 * Make an ir_assignment from \c rhs to \c lhs, performing appropriate 404 * bitcasts if necessary to match up types. 405 * 406 * This function is called when unpacking varyings. 407 */ 408void 409lower_packed_varyings_visitor::bitwise_assign_unpack(ir_rvalue *lhs, 410 ir_rvalue *rhs) 411{ 412 if (lhs->type->base_type != rhs->type->base_type) { 413 /* Since we only mix types in flat varyings, and we always store flat 414 * varyings as type ivec4, we need only produce conversions from int to 415 * (uint or float). 416 */ 417 assert(rhs->type->base_type == GLSL_TYPE_INT); 418 switch (lhs->type->base_type) { 419 case GLSL_TYPE_UINT: 420 rhs = new(this->mem_ctx) 421 ir_expression(ir_unop_i2u, lhs->type, rhs); 422 break; 423 case GLSL_TYPE_FLOAT: 424 rhs = new(this->mem_ctx) 425 ir_expression(ir_unop_bitcast_i2f, lhs->type, rhs); 426 break; 427 case GLSL_TYPE_DOUBLE: 428 assert(lhs->type->vector_elements <= 2); 429 if (lhs->type->vector_elements == 2) { 430 ir_variable *t = new(mem_ctx) ir_variable(lhs->type, "unpack", ir_var_temporary); 431 assert(rhs->type->vector_elements == 4); 432 this->out_variables->push_tail(t); 433 this->out_instructions->push_tail( 434 assign(t, expr(ir_unop_pack_double_2x32, i2u(swizzle_xy(rhs->clone(mem_ctx, NULL)))), 0x1)); 435 this->out_instructions->push_tail( 436 assign(t, expr(ir_unop_pack_double_2x32, i2u(swizzle(rhs->clone(mem_ctx, NULL), SWIZZLE_ZWZW, 2))), 0x2)); 437 rhs = deref(t).val; 438 } else { 439 rhs = expr(ir_unop_pack_double_2x32, i2u(rhs)); 440 } 441 break; 442 case GLSL_TYPE_INT64: 443 assert(lhs->type->vector_elements <= 2); 444 if (lhs->type->vector_elements == 2) { 445 ir_variable *t = new(mem_ctx) ir_variable(lhs->type, "unpack", ir_var_temporary); 446 assert(rhs->type->vector_elements == 4); 447 this->out_variables->push_tail(t); 448 this->out_instructions->push_tail( 449 assign(t, expr(ir_unop_pack_int_2x32, swizzle_xy(rhs->clone(mem_ctx, NULL))), 0x1)); 450 this->out_instructions->push_tail( 451 assign(t, expr(ir_unop_pack_int_2x32, swizzle(rhs->clone(mem_ctx, NULL), SWIZZLE_ZWZW, 2)), 0x2)); 452 rhs = deref(t).val; 453 } else { 454 rhs = expr(ir_unop_pack_int_2x32, rhs); 455 } 456 break; 457 case GLSL_TYPE_UINT64: 458 assert(lhs->type->vector_elements <= 2); 459 if (lhs->type->vector_elements == 2) { 460 ir_variable *t = new(mem_ctx) ir_variable(lhs->type, "unpack", ir_var_temporary); 461 assert(rhs->type->vector_elements == 4); 462 this->out_variables->push_tail(t); 463 this->out_instructions->push_tail( 464 assign(t, expr(ir_unop_pack_uint_2x32, i2u(swizzle_xy(rhs->clone(mem_ctx, NULL)))), 0x1)); 465 this->out_instructions->push_tail( 466 assign(t, expr(ir_unop_pack_uint_2x32, i2u(swizzle(rhs->clone(mem_ctx, NULL), SWIZZLE_ZWZW, 2))), 0x2)); 467 rhs = deref(t).val; 468 } else { 469 rhs = expr(ir_unop_pack_uint_2x32, i2u(rhs)); 470 } 471 break; 472 case GLSL_TYPE_SAMPLER: 473 rhs = new(mem_ctx) 474 ir_expression(ir_unop_pack_sampler_2x32, lhs->type, i2u(rhs)); 475 break; 476 case GLSL_TYPE_IMAGE: 477 rhs = new(mem_ctx) 478 ir_expression(ir_unop_pack_image_2x32, lhs->type, i2u(rhs)); 479 break; 480 default: 481 assert(!"Unexpected type conversion while lowering varyings"); 482 break; 483 } 484 } 485 this->out_instructions->push_tail(new(this->mem_ctx) ir_assignment(lhs, rhs)); 486} 487 488 489/** 490 * Recursively pack or unpack the given varying (or portion of a varying) by 491 * traversing all of its constituent vectors. 492 * 493 * \param fine_location is the location where the first constituent vector 494 * should be packed--the word "fine" indicates that this location is expressed 495 * in multiples of a float, rather than multiples of a vec4 as is used 496 * elsewhere in Mesa. 497 * 498 * \param gs_input_toplevel should be set to true if we are lowering geometry 499 * shader inputs, and we are currently lowering the whole input variable 500 * (i.e. we are lowering the array whose index selects the vertex). 501 * 502 * \param vertex_index: if we are lowering geometry shader inputs, and the 503 * level of the array that we are currently lowering is *not* the top level, 504 * then this indicates which vertex we are currently lowering. Otherwise it 505 * is ignored. 506 * 507 * \return the location where the next constituent vector (after this one) 508 * should be packed. 509 */ 510unsigned 511lower_packed_varyings_visitor::lower_rvalue(ir_rvalue *rvalue, 512 unsigned fine_location, 513 ir_variable *unpacked_var, 514 const char *name, 515 bool gs_input_toplevel, 516 unsigned vertex_index) 517{ 518 unsigned dmul = rvalue->type->is_64bit() ? 2 : 1; 519 /* When gs_input_toplevel is set, we should be looking at a geometry shader 520 * input array. 521 */ 522 assert(!gs_input_toplevel || rvalue->type->is_array()); 523 524 if (rvalue->type->is_struct()) { 525 for (unsigned i = 0; i < rvalue->type->length; i++) { 526 if (i != 0) 527 rvalue = rvalue->clone(this->mem_ctx, NULL); 528 const char *field_name = rvalue->type->fields.structure[i].name; 529 ir_dereference_record *dereference_record = new(this->mem_ctx) 530 ir_dereference_record(rvalue, field_name); 531 char *deref_name 532 = ralloc_asprintf(this->mem_ctx, "%s.%s", name, field_name); 533 fine_location = this->lower_rvalue(dereference_record, fine_location, 534 unpacked_var, deref_name, false, 535 vertex_index); 536 } 537 return fine_location; 538 } else if (rvalue->type->is_array()) { 539 /* Arrays are packed/unpacked by considering each array element in 540 * sequence. 541 */ 542 return this->lower_arraylike(rvalue, rvalue->type->array_size(), 543 fine_location, unpacked_var, name, 544 gs_input_toplevel, vertex_index); 545 } else if (rvalue->type->is_matrix()) { 546 /* Matrices are packed/unpacked by considering each column vector in 547 * sequence. 548 */ 549 return this->lower_arraylike(rvalue, rvalue->type->matrix_columns, 550 fine_location, unpacked_var, name, 551 false, vertex_index); 552 } else if (rvalue->type->vector_elements * dmul + 553 fine_location % 4 > 4) { 554 /* This vector is going to be "double parked" across two varying slots, 555 * so handle it as two separate assignments. For doubles, a dvec3/dvec4 556 * can end up being spread over 3 slots. However the second splitting 557 * will happen later, here we just always want to split into 2. 558 */ 559 unsigned left_components, right_components; 560 unsigned left_swizzle_values[4] = { 0, 0, 0, 0 }; 561 unsigned right_swizzle_values[4] = { 0, 0, 0, 0 }; 562 char left_swizzle_name[4] = { 0, 0, 0, 0 }; 563 char right_swizzle_name[4] = { 0, 0, 0, 0 }; 564 565 left_components = 4 - fine_location % 4; 566 if (rvalue->type->is_64bit()) { 567 /* We might actually end up with 0 left components! */ 568 left_components /= 2; 569 } 570 right_components = rvalue->type->vector_elements - left_components; 571 572 for (unsigned i = 0; i < left_components; i++) { 573 left_swizzle_values[i] = i; 574 left_swizzle_name[i] = "xyzw"[i]; 575 } 576 for (unsigned i = 0; i < right_components; i++) { 577 right_swizzle_values[i] = i + left_components; 578 right_swizzle_name[i] = "xyzw"[i + left_components]; 579 } 580 ir_swizzle *left_swizzle = new(this->mem_ctx) 581 ir_swizzle(rvalue, left_swizzle_values, left_components); 582 ir_swizzle *right_swizzle = new(this->mem_ctx) 583 ir_swizzle(rvalue->clone(this->mem_ctx, NULL), right_swizzle_values, 584 right_components); 585 char *left_name 586 = ralloc_asprintf(this->mem_ctx, "%s.%s", name, left_swizzle_name); 587 char *right_name 588 = ralloc_asprintf(this->mem_ctx, "%s.%s", name, right_swizzle_name); 589 if (left_components) 590 fine_location = this->lower_rvalue(left_swizzle, fine_location, 591 unpacked_var, left_name, false, 592 vertex_index); 593 else 594 /* Top up the fine location to the next slot */ 595 fine_location++; 596 return this->lower_rvalue(right_swizzle, fine_location, unpacked_var, 597 right_name, false, vertex_index); 598 } else { 599 /* No special handling is necessary; pack the rvalue into the 600 * varying. 601 */ 602 unsigned swizzle_values[4] = { 0, 0, 0, 0 }; 603 unsigned components = rvalue->type->vector_elements * dmul; 604 unsigned location = fine_location / 4; 605 unsigned location_frac = fine_location % 4; 606 for (unsigned i = 0; i < components; ++i) 607 swizzle_values[i] = i + location_frac; 608 ir_dereference *packed_deref = 609 this->get_packed_varying_deref(location, unpacked_var, name, 610 vertex_index); 611 if (unpacked_var->data.stream != 0) { 612 assert(unpacked_var->data.stream < 4); 613 ir_variable *packed_var = packed_deref->variable_referenced(); 614 for (unsigned i = 0; i < components; ++i) { 615 packed_var->data.stream |= 616 unpacked_var->data.stream << (2 * (location_frac + i)); 617 } 618 } 619 ir_swizzle *swizzle = new(this->mem_ctx) 620 ir_swizzle(packed_deref, swizzle_values, components); 621 if (this->mode == ir_var_shader_out) { 622 this->bitwise_assign_pack(swizzle, rvalue); 623 } else { 624 this->bitwise_assign_unpack(rvalue, swizzle); 625 } 626 return fine_location + components; 627 } 628} 629 630/** 631 * Recursively pack or unpack a varying for which we need to iterate over its 632 * constituent elements, accessing each one using an ir_dereference_array. 633 * This takes care of both arrays and matrices, since ir_dereference_array 634 * treats a matrix like an array of its column vectors. 635 * 636 * \param gs_input_toplevel should be set to true if we are lowering geometry 637 * shader inputs, and we are currently lowering the whole input variable 638 * (i.e. we are lowering the array whose index selects the vertex). 639 * 640 * \param vertex_index: if we are lowering geometry shader inputs, and the 641 * level of the array that we are currently lowering is *not* the top level, 642 * then this indicates which vertex we are currently lowering. Otherwise it 643 * is ignored. 644 */ 645unsigned 646lower_packed_varyings_visitor::lower_arraylike(ir_rvalue *rvalue, 647 unsigned array_size, 648 unsigned fine_location, 649 ir_variable *unpacked_var, 650 const char *name, 651 bool gs_input_toplevel, 652 unsigned vertex_index) 653{ 654 for (unsigned i = 0; i < array_size; i++) { 655 if (i != 0) 656 rvalue = rvalue->clone(this->mem_ctx, NULL); 657 ir_constant *constant = new(this->mem_ctx) ir_constant(i); 658 ir_dereference_array *dereference_array = new(this->mem_ctx) 659 ir_dereference_array(rvalue, constant); 660 if (gs_input_toplevel) { 661 /* Geometry shader inputs are a special case. Instead of storing 662 * each element of the array at a different location, all elements 663 * are at the same location, but with a different vertex index. 664 */ 665 (void) this->lower_rvalue(dereference_array, fine_location, 666 unpacked_var, name, false, i); 667 } else { 668 char *subscripted_name 669 = ralloc_asprintf(this->mem_ctx, "%s[%d]", name, i); 670 fine_location = 671 this->lower_rvalue(dereference_array, fine_location, 672 unpacked_var, subscripted_name, 673 false, vertex_index); 674 } 675 } 676 return fine_location; 677} 678 679/** 680 * Retrieve the packed varying corresponding to the given varying location. 681 * If no packed varying has been created for the given varying location yet, 682 * create it and add it to the shader before returning it. 683 * 684 * The newly created varying inherits its interpolation parameters from \c 685 * unpacked_var. Its base type is ivec4 if we are lowering a flat varying, 686 * vec4 otherwise. 687 * 688 * \param vertex_index: if we are lowering geometry shader inputs, then this 689 * indicates which vertex we are currently lowering. Otherwise it is ignored. 690 */ 691ir_dereference * 692lower_packed_varyings_visitor::get_packed_varying_deref( 693 unsigned location, ir_variable *unpacked_var, const char *name, 694 unsigned vertex_index) 695{ 696 unsigned slot = location - VARYING_SLOT_VAR0; 697 assert(slot < locations_used); 698 if (this->packed_varyings[slot] == NULL) { 699 char *packed_name = ralloc_asprintf(this->mem_ctx, "packed:%s", name); 700 const glsl_type *packed_type; 701 assert(components[slot] != 0); 702 if (unpacked_var->is_interpolation_flat()) 703 packed_type = glsl_type::get_instance(GLSL_TYPE_INT, components[slot], 1); 704 else 705 packed_type = glsl_type::get_instance(GLSL_TYPE_FLOAT, components[slot], 1); 706 if (this->gs_input_vertices != 0) { 707 packed_type = 708 glsl_type::get_array_instance(packed_type, 709 this->gs_input_vertices); 710 } 711 ir_variable *packed_var = new(this->mem_ctx) 712 ir_variable(packed_type, packed_name, this->mode); 713 if (this->gs_input_vertices != 0) { 714 /* Prevent update_array_sizes() from messing with the size of the 715 * array. 716 */ 717 packed_var->data.max_array_access = this->gs_input_vertices - 1; 718 } 719 packed_var->data.centroid = unpacked_var->data.centroid; 720 packed_var->data.sample = unpacked_var->data.sample; 721 packed_var->data.patch = unpacked_var->data.patch; 722 packed_var->data.interpolation = 723 packed_type->without_array() == glsl_type::ivec4_type 724 ? unsigned(INTERP_MODE_FLAT) : unpacked_var->data.interpolation; 725 packed_var->data.location = location; 726 packed_var->data.precision = unpacked_var->data.precision; 727 packed_var->data.always_active_io = unpacked_var->data.always_active_io; 728 packed_var->data.stream = 1u << 31; 729 unpacked_var->insert_before(packed_var); 730 this->packed_varyings[slot] = packed_var; 731 } else { 732 ir_variable *var = this->packed_varyings[slot]; 733 734 /* The slot needs to be marked as always active if any variable that got 735 * packed there was. 736 */ 737 var->data.always_active_io |= unpacked_var->data.always_active_io; 738 739 /* For geometry shader inputs, only update the packed variable name the 740 * first time we visit each component. 741 */ 742 if (this->gs_input_vertices == 0 || vertex_index == 0) { 743 if (var->is_name_ralloced()) 744 ralloc_asprintf_append((char **) &var->name, ",%s", name); 745 else 746 var->name = ralloc_asprintf(var, "%s,%s", var->name, name); 747 } 748 } 749 750 ir_dereference *deref = new(this->mem_ctx) 751 ir_dereference_variable(this->packed_varyings[slot]); 752 if (this->gs_input_vertices != 0) { 753 /* When lowering GS inputs, the packed variable is an array, so we need 754 * to dereference it using vertex_index. 755 */ 756 ir_constant *constant = new(this->mem_ctx) ir_constant(vertex_index); 757 deref = new(this->mem_ctx) ir_dereference_array(deref, constant); 758 } 759 return deref; 760} 761 762bool 763lower_packed_varyings_visitor::needs_lowering(ir_variable *var) 764{ 765 /* Things composed of vec4's, varyings with explicitly assigned 766 * locations or varyings marked as must_be_shader_input (which might be used 767 * by interpolateAt* functions) shouldn't be lowered. Everything else can be. 768 */ 769 if (var->data.explicit_location || var->data.must_be_shader_input) 770 return false; 771 772 /* Override disable_varying_packing if the var is only used by transform 773 * feedback. Also override it if transform feedback is enabled and the 774 * variable is an array, struct or matrix as the elements of these types 775 * will always have the same interpolation and therefore are safe to pack. 776 */ 777 const glsl_type *type = var->type; 778 if (disable_varying_packing && !var->data.is_xfb_only && 779 !((type->is_array() || type->is_struct() || type->is_matrix()) && 780 xfb_enabled)) 781 return false; 782 783 type = type->without_array(); 784 if (type->vector_elements == 4 && !type->is_64bit()) 785 return false; 786 return true; 787} 788 789 790/** 791 * Visitor that splices varying packing code before every use of EmitVertex() 792 * in a geometry shader. 793 */ 794class lower_packed_varyings_gs_splicer : public ir_hierarchical_visitor 795{ 796public: 797 explicit lower_packed_varyings_gs_splicer(void *mem_ctx, 798 const exec_list *instructions); 799 800 virtual ir_visitor_status visit_leave(ir_emit_vertex *ev); 801 802private: 803 /** 804 * Memory context used to allocate new instructions for the shader. 805 */ 806 void * const mem_ctx; 807 808 /** 809 * Instructions that should be spliced into place before each EmitVertex() 810 * call. 811 */ 812 const exec_list *instructions; 813}; 814 815 816lower_packed_varyings_gs_splicer::lower_packed_varyings_gs_splicer( 817 void *mem_ctx, const exec_list *instructions) 818 : mem_ctx(mem_ctx), instructions(instructions) 819{ 820} 821 822 823ir_visitor_status 824lower_packed_varyings_gs_splicer::visit_leave(ir_emit_vertex *ev) 825{ 826 foreach_in_list(ir_instruction, ir, this->instructions) { 827 ev->insert_before(ir->clone(this->mem_ctx, NULL)); 828 } 829 return visit_continue; 830} 831 832/** 833 * Visitor that splices varying packing code before every return. 834 */ 835class lower_packed_varyings_return_splicer : public ir_hierarchical_visitor 836{ 837public: 838 explicit lower_packed_varyings_return_splicer(void *mem_ctx, 839 const exec_list *instructions); 840 841 virtual ir_visitor_status visit_leave(ir_return *ret); 842 843private: 844 /** 845 * Memory context used to allocate new instructions for the shader. 846 */ 847 void * const mem_ctx; 848 849 /** 850 * Instructions that should be spliced into place before each return. 851 */ 852 const exec_list *instructions; 853}; 854 855 856lower_packed_varyings_return_splicer::lower_packed_varyings_return_splicer( 857 void *mem_ctx, const exec_list *instructions) 858 : mem_ctx(mem_ctx), instructions(instructions) 859{ 860} 861 862 863ir_visitor_status 864lower_packed_varyings_return_splicer::visit_leave(ir_return *ret) 865{ 866 foreach_in_list(ir_instruction, ir, this->instructions) { 867 ret->insert_before(ir->clone(this->mem_ctx, NULL)); 868 } 869 return visit_continue; 870} 871 872void 873lower_packed_varyings(void *mem_ctx, unsigned locations_used, 874 const uint8_t *components, 875 ir_variable_mode mode, unsigned gs_input_vertices, 876 gl_linked_shader *shader, bool disable_varying_packing, 877 bool xfb_enabled) 878{ 879 exec_list *instructions = shader->ir; 880 ir_function *main_func = shader->symbols->get_function("main"); 881 exec_list void_parameters; 882 ir_function_signature *main_func_sig 883 = main_func->matching_signature(NULL, &void_parameters, false); 884 exec_list new_instructions, new_variables; 885 lower_packed_varyings_visitor visitor(mem_ctx, 886 locations_used, 887 components, 888 mode, 889 gs_input_vertices, 890 &new_instructions, 891 &new_variables, 892 disable_varying_packing, 893 xfb_enabled); 894 visitor.run(shader); 895 if (mode == ir_var_shader_out) { 896 if (shader->Stage == MESA_SHADER_GEOMETRY) { 897 /* For geometry shaders, outputs need to be lowered before each call 898 * to EmitVertex() 899 */ 900 lower_packed_varyings_gs_splicer splicer(mem_ctx, &new_instructions); 901 902 /* Add all the variables in first. */ 903 main_func_sig->body.get_head_raw()->insert_before(&new_variables); 904 905 /* Now update all the EmitVertex instances */ 906 splicer.run(instructions); 907 } else { 908 /* For other shader types, outputs need to be lowered before each 909 * return statement and at the end of main() 910 */ 911 912 lower_packed_varyings_return_splicer splicer(mem_ctx, &new_instructions); 913 914 main_func_sig->body.get_head_raw()->insert_before(&new_variables); 915 916 splicer.run(instructions); 917 918 /* Lower outputs at the end of main() if the last instruction is not 919 * a return statement 920 */ 921 if (((ir_instruction*)instructions->get_tail())->ir_type != ir_type_return) { 922 main_func_sig->body.append_list(&new_instructions); 923 } 924 } 925 } else { 926 /* Shader inputs need to be lowered at the beginning of main() */ 927 main_func_sig->body.get_head_raw()->insert_before(&new_instructions); 928 main_func_sig->body.get_head_raw()->insert_before(&new_variables); 929 } 930} 931