1 /* 2 * Copyright (c) 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 21 * DEALINGS IN THE SOFTWARE. 22 */ 23 24 /** 25 * \file lower_buffer_access.cpp 26 * 27 * Helper for IR lowering pass to replace dereferences of buffer object based 28 * shader variables with intrinsic function calls. 29 * 30 * This helper is used by lowering passes for UBOs, SSBOs and compute shader 31 * shared variables. 32 */ 33 34 #include "lower_buffer_access.h" 35 #include "ir_builder.h" 36 #include "main/macros.h" 37 #include "util/list.h" 38 #include "glsl_parser_extras.h" 39 #include "linker.h" 40 41 using namespace ir_builder; 42 43 namespace lower_buffer_access { 44 45 static inline int 46 writemask_for_size(unsigned n) 47 { 48 return ((1 << n) - 1); 49 } 50 51 /** 52 * Takes a deref and recursively calls itself to break the deref down to the 53 * point that the reads or writes generated are contiguous scalars or vectors. 54 */ 55 void 56 lower_buffer_access::emit_access(void *mem_ctx, 57 bool is_write, 58 ir_dereference *deref, 59 ir_variable *base_offset, 60 unsigned int deref_offset, 61 bool row_major, 62 const glsl_type *matrix_type, 63 enum glsl_interface_packing packing, 64 unsigned int write_mask) 65 { 66 if (deref->type->is_record()) { 67 unsigned int field_offset = 0; 68 69 for (unsigned i = 0; i < deref->type->length; i++) { 70 const struct glsl_struct_field *field = 71 &deref->type->fields.structure[i]; 72 ir_dereference *field_deref = 73 new(mem_ctx) ir_dereference_record(deref->clone(mem_ctx, NULL), 74 field->name); 75 76 unsigned field_align; 77 if (packing == GLSL_INTERFACE_PACKING_STD430) 78 field_align = field->type->std430_base_alignment(row_major); 79 else 80 field_align = field->type->std140_base_alignment(row_major); 81 field_offset = glsl_align(field_offset, field_align); 82 83 emit_access(mem_ctx, is_write, field_deref, base_offset, 84 deref_offset + field_offset, 85 row_major, NULL, packing, 86 writemask_for_size(field_deref->type->vector_elements)); 87 88 if (packing == GLSL_INTERFACE_PACKING_STD430) 89 field_offset += field->type->std430_size(row_major); 90 else 91 field_offset += field->type->std140_size(row_major); 92 } 93 return; 94 } 95 96 if (deref->type->is_array()) { 97 unsigned array_stride = packing == GLSL_INTERFACE_PACKING_STD430 ? 98 deref->type->fields.array->std430_array_stride(row_major) : 99 glsl_align(deref->type->fields.array->std140_size(row_major), 16); 100 101 for (unsigned i = 0; i < deref->type->length; i++) { 102 ir_constant *element = new(mem_ctx) ir_constant(i); 103 ir_dereference *element_deref = 104 new(mem_ctx) ir_dereference_array(deref->clone(mem_ctx, NULL), 105 element); 106 emit_access(mem_ctx, is_write, element_deref, base_offset, 107 deref_offset + i * array_stride, 108 row_major, NULL, packing, 109 writemask_for_size(element_deref->type->vector_elements)); 110 } 111 return; 112 } 113 114 if (deref->type->is_matrix()) { 115 for (unsigned i = 0; i < deref->type->matrix_columns; i++) { 116 ir_constant *col = new(mem_ctx) ir_constant(i); 117 ir_dereference *col_deref = 118 new(mem_ctx) ir_dereference_array(deref->clone(mem_ctx, NULL), col); 119 120 /* For a row-major matrix, the next column starts at the next 121 * element. Otherwise it is offset by the matrix stride. 122 */ 123 const unsigned size_mul = row_major 124 ? (deref->type->is_double() ? 8 : 4) 125 : link_calculate_matrix_stride(deref->type, row_major, packing); 126 127 emit_access(mem_ctx, is_write, col_deref, base_offset, 128 deref_offset + i * size_mul, 129 row_major, deref->type, packing, 130 writemask_for_size(col_deref->type->vector_elements)); 131 } 132 return; 133 } 134 135 assert(deref->type->is_scalar() || deref->type->is_vector()); 136 137 if (!row_major) { 138 ir_rvalue *offset = 139 add(base_offset, new(mem_ctx) ir_constant(deref_offset)); 140 unsigned mask = 141 is_write ? write_mask : (1 << deref->type->vector_elements) - 1; 142 insert_buffer_access(mem_ctx, deref, deref->type, offset, mask, -1); 143 } else { 144 /* We're dereffing a column out of a row-major matrix, so we 145 * gather the vector from each stored row. 146 */ 147 assert(deref->type->is_float() || deref->type->is_double()); 148 assert(matrix_type != NULL); 149 150 const unsigned matrix_stride = 151 link_calculate_matrix_stride(matrix_type, row_major, packing); 152 153 const glsl_type *deref_type = deref->type->get_scalar_type(); 154 155 for (unsigned i = 0; i < deref->type->vector_elements; i++) { 156 ir_rvalue *chan_offset = 157 add(base_offset, 158 new(mem_ctx) ir_constant(deref_offset + i * matrix_stride)); 159 if (!is_write || ((1U << i) & write_mask)) 160 insert_buffer_access(mem_ctx, deref, deref_type, chan_offset, 161 (1U << i), i); 162 } 163 } 164 } 165 166 /** 167 * Determine if a thing being dereferenced is row-major 168 * 169 * There is some trickery here. 170 * 171 * If the thing being dereferenced is a member of uniform block \b without an 172 * instance name, then the name of the \c ir_variable is the field name of an 173 * interface type. If this field is row-major, then the thing referenced is 174 * row-major. 175 * 176 * If the thing being dereferenced is a member of uniform block \b with an 177 * instance name, then the last dereference in the tree will be an 178 * \c ir_dereference_record. If that record field is row-major, then the 179 * thing referenced is row-major. 180 */ 181 bool 182 lower_buffer_access::is_dereferenced_thing_row_major(const ir_rvalue *deref) 183 { 184 bool matrix = false; 185 const ir_rvalue *ir = deref; 186 187 while (true) { 188 matrix = matrix || ir->type->without_array()->is_matrix(); 189 190 switch (ir->ir_type) { 191 case ir_type_dereference_array: { 192 const ir_dereference_array *const array_deref = 193 (const ir_dereference_array *) ir; 194 195 ir = array_deref->array; 196 break; 197 } 198 199 case ir_type_dereference_record: { 200 const ir_dereference_record *const record_deref = 201 (const ir_dereference_record *) ir; 202 203 ir = record_deref->record; 204 205 const int idx = record_deref->field_idx; 206 assert(idx >= 0); 207 208 const enum glsl_matrix_layout matrix_layout = 209 glsl_matrix_layout(ir->type->fields.structure[idx].matrix_layout); 210 211 switch (matrix_layout) { 212 case GLSL_MATRIX_LAYOUT_INHERITED: 213 break; 214 case GLSL_MATRIX_LAYOUT_COLUMN_MAJOR: 215 return false; 216 case GLSL_MATRIX_LAYOUT_ROW_MAJOR: 217 return matrix || deref->type->without_array()->is_record(); 218 } 219 220 break; 221 } 222 223 case ir_type_dereference_variable: { 224 const ir_dereference_variable *const var_deref = 225 (const ir_dereference_variable *) ir; 226 227 const enum glsl_matrix_layout matrix_layout = 228 glsl_matrix_layout(var_deref->var->data.matrix_layout); 229 230 switch (matrix_layout) { 231 case GLSL_MATRIX_LAYOUT_INHERITED: { 232 /* For interface block matrix variables we handle inherited 233 * layouts at HIR generation time, but we don't do that for shared 234 * variables, which are always column-major 235 */ 236 MAYBE_UNUSED ir_variable *var = deref->variable_referenced(); 237 assert((var->is_in_buffer_block() && !matrix) || 238 var->data.mode == ir_var_shader_shared); 239 return false; 240 } 241 case GLSL_MATRIX_LAYOUT_COLUMN_MAJOR: 242 return false; 243 case GLSL_MATRIX_LAYOUT_ROW_MAJOR: 244 return matrix || deref->type->without_array()->is_record(); 245 } 246 247 unreachable("invalid matrix layout"); 248 break; 249 } 250 251 default: 252 return false; 253 } 254 } 255 256 /* The tree must have ended with a dereference that wasn't an 257 * ir_dereference_variable. That is invalid, and it should be impossible. 258 */ 259 unreachable("invalid dereference tree"); 260 return false; 261 } 262 263 /** 264 * This function initializes various values that will be used later by 265 * emit_access when actually emitting loads or stores. 266 * 267 * Note: const_offset is an input as well as an output, clients must 268 * initialize it to the offset of the variable in the underlying block, and 269 * this function will adjust it by adding the constant offset of the member 270 * being accessed into that variable. 271 */ 272 void 273 lower_buffer_access::setup_buffer_access(void *mem_ctx, 274 ir_rvalue *deref, 275 ir_rvalue **offset, 276 unsigned *const_offset, 277 bool *row_major, 278 const glsl_type **matrix_type, 279 const glsl_struct_field **struct_field, 280 enum glsl_interface_packing packing) 281 { 282 *offset = new(mem_ctx) ir_constant(0u); 283 *row_major = is_dereferenced_thing_row_major(deref); 284 *matrix_type = NULL; 285 286 /* Calculate the offset to the start of the region of the UBO 287 * dereferenced by *rvalue. This may be a variable offset if an 288 * array dereference has a variable index. 289 */ 290 while (deref) { 291 switch (deref->ir_type) { 292 case ir_type_dereference_variable: { 293 deref = NULL; 294 break; 295 } 296 297 case ir_type_dereference_array: { 298 ir_dereference_array *deref_array = (ir_dereference_array *) deref; 299 unsigned array_stride; 300 if (deref_array->array->type->is_vector()) { 301 /* We get this when storing or loading a component out of a vector 302 * with a non-constant index. This happens for v[i] = f where v is 303 * a vector (or m[i][j] = f where m is a matrix). If we don't 304 * lower that here, it gets turned into v = vector_insert(v, i, 305 * f), which loads the entire vector, modifies one component and 306 * then write the entire thing back. That breaks if another 307 * thread or SIMD channel is modifying the same vector. 308 */ 309 array_stride = 4; 310 if (deref_array->array->type->is_64bit()) 311 array_stride *= 2; 312 } else if (deref_array->array->type->is_matrix() && *row_major) { 313 /* When loading a vector out of a row major matrix, the 314 * step between the columns (vectors) is the size of a 315 * float, while the step between the rows (elements of a 316 * vector) is handled below in emit_ubo_loads. 317 */ 318 array_stride = 4; 319 if (deref_array->array->type->is_64bit()) 320 array_stride *= 2; 321 *matrix_type = deref_array->array->type; 322 } else if (deref_array->type->without_array()->is_interface()) { 323 /* We're processing an array dereference of an interface instance 324 * array. The thing being dereferenced *must* be a variable 325 * dereference because interfaces cannot be embedded in other 326 * types. In terms of calculating the offsets for the lowering 327 * pass, we don't care about the array index. All elements of an 328 * interface instance array will have the same offsets relative to 329 * the base of the block that backs them. 330 */ 331 deref = deref_array->array->as_dereference(); 332 break; 333 } else { 334 /* Whether or not the field is row-major (because it might be a 335 * bvec2 or something) does not affect the array itself. We need 336 * to know whether an array element in its entirety is row-major. 337 */ 338 const bool array_row_major = 339 is_dereferenced_thing_row_major(deref_array); 340 341 /* The array type will give the correct interface packing 342 * information 343 */ 344 if (packing == GLSL_INTERFACE_PACKING_STD430) { 345 array_stride = deref_array->type->std430_array_stride(array_row_major); 346 } else { 347 array_stride = deref_array->type->std140_size(array_row_major); 348 array_stride = glsl_align(array_stride, 16); 349 } 350 } 351 352 ir_rvalue *array_index = deref_array->array_index; 353 if (array_index->type->base_type == GLSL_TYPE_INT) 354 array_index = i2u(array_index); 355 356 ir_constant *const_index = 357 array_index->constant_expression_value(mem_ctx, NULL); 358 if (const_index) { 359 *const_offset += array_stride * const_index->value.u[0]; 360 } else { 361 *offset = add(*offset, 362 mul(array_index, 363 new(mem_ctx) ir_constant(array_stride))); 364 } 365 deref = deref_array->array->as_dereference(); 366 break; 367 } 368 369 case ir_type_dereference_record: { 370 ir_dereference_record *deref_record = (ir_dereference_record *) deref; 371 const glsl_type *struct_type = deref_record->record->type; 372 unsigned intra_struct_offset = 0; 373 374 for (unsigned int i = 0; i < struct_type->length; i++) { 375 const glsl_type *type = struct_type->fields.structure[i].type; 376 377 ir_dereference_record *field_deref = new(mem_ctx) 378 ir_dereference_record(deref_record->record, 379 struct_type->fields.structure[i].name); 380 const bool field_row_major = 381 is_dereferenced_thing_row_major(field_deref); 382 383 ralloc_free(field_deref); 384 385 unsigned field_align = 0; 386 387 if (packing == GLSL_INTERFACE_PACKING_STD430) 388 field_align = type->std430_base_alignment(field_row_major); 389 else 390 field_align = type->std140_base_alignment(field_row_major); 391 392 if (struct_type->fields.structure[i].offset != -1) { 393 intra_struct_offset = struct_type->fields.structure[i].offset; 394 } 395 396 intra_struct_offset = glsl_align(intra_struct_offset, field_align); 397 398 assert(deref_record->field_idx >= 0); 399 if (i == (unsigned) deref_record->field_idx) { 400 if (struct_field) 401 *struct_field = &struct_type->fields.structure[i]; 402 break; 403 } 404 405 if (packing == GLSL_INTERFACE_PACKING_STD430) 406 intra_struct_offset += type->std430_size(field_row_major); 407 else 408 intra_struct_offset += type->std140_size(field_row_major); 409 410 /* If the field just examined was itself a structure, apply rule 411 * #9: 412 * 413 * "The structure may have padding at the end; the base offset 414 * of the member following the sub-structure is rounded up to 415 * the next multiple of the base alignment of the structure." 416 */ 417 if (type->without_array()->is_record()) { 418 intra_struct_offset = glsl_align(intra_struct_offset, 419 field_align); 420 421 } 422 } 423 424 *const_offset += intra_struct_offset; 425 deref = deref_record->record->as_dereference(); 426 break; 427 } 428 429 case ir_type_swizzle: { 430 ir_swizzle *deref_swizzle = (ir_swizzle *) deref; 431 432 assert(deref_swizzle->mask.num_components == 1); 433 434 *const_offset += deref_swizzle->mask.x * sizeof(int); 435 deref = deref_swizzle->val->as_dereference(); 436 break; 437 } 438 439 default: 440 assert(!"not reached"); 441 deref = NULL; 442 break; 443 } 444 } 445 } 446 447 } /* namespace lower_buffer_access */ 448
