src/lib/lttng-ctl/filter/filter-visitor-generate-bytecode.c

   1 /*
   2  * filter-visitor-generate-bytecode.c
   3  *
   4  * LTTng filter bytecode generation
   5  *
   6  * Copyright 2012 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   7  *
   8  * This library is free software; you can redistribute it and/or modify it
   9  * under the terms of the GNU Lesser General Public License, version 2.1 only,
  10  * as published by the Free Software Foundation.
  11  *
  12  * This library is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public License
  18  * along with this library; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 #include <stdlib.h>
  23 #include <string.h>
  24 #include <errno.h>
  25 #include <common/align.h>
  26 #include <common/compat/string.h>
  27
  28 #include "filter-bytecode.h"
  29 #include "filter-ir.h"
  30 #include "filter-ast.h"
  31
  32 #include <common/macros.h>
  33
  34 #ifndef max_t
  35 #define max_t(type, a, b)       ((type) ((a) > (b) ? (a) : (b)))
  36 #endif
  37
  38 #define INIT_ALLOC_SIZE         4
  39
  40 static
  41 int recursive_visit_gen_bytecode(struct filter_parser_ctx *ctx,
  42                 struct ir_op *node);
  43
  44 static inline int get_count_order(unsigned int count)
  45 {
  46         int order;
  47
  48         order = lttng_fls(count) - 1;
  49         if (count & (count - 1))
  50                 order++;
  51         return order;
  52 }
  53
  54 static
  55 int bytecode_init(struct lttng_filter_bytecode_alloc **fb)
  56 {
  57         uint32_t alloc_len;
  58
  59         alloc_len = sizeof(struct lttng_filter_bytecode_alloc) + INIT_ALLOC_SIZE;
  60         *fb = calloc(alloc_len, 1);
  61         if (!*fb) {
  62                 return -ENOMEM;
  63         } else {
  64                 (*fb)->alloc_len = alloc_len;
  65                 return 0;
  66         }
  67 }
  68
  69 static
  70 int32_t bytecode_reserve(struct lttng_filter_bytecode_alloc **fb, uint32_t align, uint32_t len)
  71 {
  72         int32_t ret;
  73         uint32_t padding = offset_align((*fb)->b.len, align);
  74         uint32_t new_len = (*fb)->b.len + padding + len;
  75         uint32_t new_alloc_len = sizeof(struct lttng_filter_bytecode_alloc) + new_len;
  76         uint32_t old_alloc_len = (*fb)->alloc_len;
  77
  78         if (new_len > LTTNG_FILTER_MAX_LEN)
  79                 return -EINVAL;
  80
  81         if (new_alloc_len > old_alloc_len) {
  82                 struct lttng_filter_bytecode_alloc *newptr;
  83
  84                 new_alloc_len =
  85                         max_t(uint32_t, 1U << get_count_order(new_alloc_len), old_alloc_len << 1);
  86                 newptr = realloc(*fb, new_alloc_len);
  87                 if (!newptr)
  88                         return -ENOMEM;
  89                 *fb = newptr;
  90                 /* We zero directly the memory from start of allocation. */
  91                 memset(&((char *) *fb)[old_alloc_len], 0, new_alloc_len - old_alloc_len);
  92                 (*fb)->alloc_len = new_alloc_len;
  93         }
  94         (*fb)->b.len += padding;
  95         ret = (*fb)->b.len;
  96         (*fb)->b.len += len;
  97         return ret;
  98 }
  99
 100 static
 101 int bytecode_push(struct lttng_filter_bytecode_alloc **fb, const void *data,
 102                 uint32_t align, uint32_t len)
 103 {
 104         int32_t offset;
 105
 106         offset = bytecode_reserve(fb, align, len);
 107         if (offset < 0)
 108                 return offset;
 109         memcpy(&(*fb)->b.data[offset], data, len);
 110         return 0;
 111 }
 112
 113 static
 114 int bytecode_push_logical(struct lttng_filter_bytecode_alloc **fb,
 115                 struct logical_op *data,
 116                 uint32_t align, uint32_t len,
 117                 uint16_t *skip_offset)
 118 {
 119         int32_t offset;
 120
 121         offset = bytecode_reserve(fb, align, len);
 122         if (offset < 0)
 123                 return offset;
 124         memcpy(&(*fb)->b.data[offset], data, len);
 125         *skip_offset =
 126                 (void *) &((struct logical_op *) &(*fb)->b.data[offset])->skip_offset
 127                         - (void *) &(*fb)->b.data[0];
 128         return 0;
 129 }
 130
 131 static
 132 int bytecode_patch(struct lttng_filter_bytecode_alloc **fb,
 133                 const void *data,
 134                 uint16_t offset,
 135                 uint32_t len)
 136 {
 137         if (offset >= (*fb)->b.len) {
 138                 return -EINVAL;
 139         }
 140         memcpy(&(*fb)->b.data[offset], data, len);
 141         return 0;
 142 }
 143
 144 static
 145 int visit_node_root(struct filter_parser_ctx *ctx, struct ir_op *node)
 146 {
 147         int ret;
 148         struct return_op insn;
 149
 150         /* Visit child */
 151         ret = recursive_visit_gen_bytecode(ctx, node->u.root.child);
 152         if (ret)
 153                 return ret;
 154
 155         /* Generate end of bytecode instruction */
 156         insn.op = FILTER_OP_RETURN;
 157         return bytecode_push(&ctx->bytecode, &insn, 1, sizeof(insn));
 158 }
 159
 160 static
 161 int visit_node_load(struct filter_parser_ctx *ctx, struct ir_op *node)
 162 {
 163         int ret;
 164
 165         switch (node->data_type) {
 166         case IR_DATA_UNKNOWN:
 167         default:
 168                 fprintf(stderr, "[error] Unknown data type in %s\n",
 169                         __func__);
 170                 return -EINVAL;
 171
 172         case IR_DATA_STRING:
 173         {
 174                 struct load_op *insn;
 175                 uint32_t insn_len = sizeof(struct load_op)
 176                         + strlen(node->u.load.u.string) + 1;
 177
 178                 insn = calloc(insn_len, 1);
 179                 if (!insn)
 180                         return -ENOMEM;
 181                 insn->op = FILTER_OP_LOAD_STRING;
 182                 strcpy(insn->data, node->u.load.u.string);
 183                 ret = bytecode_push(&ctx->bytecode, insn, 1, insn_len);
 184                 free(insn);
 185                 return ret;
 186         }
 187         case IR_DATA_NUMERIC:
 188         {
 189                 struct load_op *insn;
 190                 uint32_t insn_len = sizeof(struct load_op)
 191                         + sizeof(struct literal_numeric);
 192
 193                 insn = calloc(insn_len, 1);
 194                 if (!insn)
 195                         return -ENOMEM;
 196                 insn->op = FILTER_OP_LOAD_S64;
 197                 memcpy(insn->data, &node->u.load.u.num, sizeof(int64_t));
 198                 ret = bytecode_push(&ctx->bytecode, insn, 1, insn_len);
 199                 free(insn);
 200                 return ret;
 201         }
 202         case IR_DATA_FLOAT:
 203         {
 204                 struct load_op *insn;
 205                 uint32_t insn_len = sizeof(struct load_op)
 206                         + sizeof(struct literal_double);
 207
 208                 insn = calloc(insn_len, 1);
 209                 if (!insn)
 210                         return -ENOMEM;
 211                 insn->op = FILTER_OP_LOAD_DOUBLE;
 212                 memcpy(insn->data, &node->u.load.u.flt, sizeof(double));
 213                 ret = bytecode_push(&ctx->bytecode, insn, 1, insn_len);
 214                 free(insn);
 215                 return ret;
 216         }
 217         case IR_DATA_FIELD_REF: /* fall-through */
 218         case IR_DATA_GET_CONTEXT_REF:
 219         {
 220                 struct load_op *insn;
 221                 uint32_t insn_len = sizeof(struct load_op)
 222                         + sizeof(struct field_ref);
 223                 struct field_ref ref_offset;
 224                 uint32_t reloc_offset_u32;
 225                 uint16_t reloc_offset;
 226
 227                 insn = calloc(insn_len, 1);
 228                 if (!insn)
 229                         return -ENOMEM;
 230                 switch(node->data_type) {
 231                 case IR_DATA_FIELD_REF:
 232                         insn->op = FILTER_OP_LOAD_FIELD_REF;
 233                         break;
 234                 case IR_DATA_GET_CONTEXT_REF:
 235                         insn->op = FILTER_OP_GET_CONTEXT_REF;
 236                         break;
 237                 default:
 238                         free(insn);
 239                         return -EINVAL;
 240                 }
 241                 ref_offset.offset = (uint16_t) -1U;
 242                 memcpy(insn->data, &ref_offset, sizeof(ref_offset));
 243                 /* reloc_offset points to struct load_op */
 244                 reloc_offset_u32 = bytecode_get_len(&ctx->bytecode->b);
 245                 if (reloc_offset_u32 > LTTNG_FILTER_MAX_LEN - 1) {
 246                         free(insn);
 247                         return -EINVAL;
 248                 }
 249                 reloc_offset = (uint16_t) reloc_offset_u32;
 250                 ret = bytecode_push(&ctx->bytecode, insn, 1, insn_len);
 251                 if (ret) {
 252                         free(insn);
 253                         return ret;
 254                 }
 255                 /* append reloc */
 256                 ret = bytecode_push(&ctx->bytecode_reloc, &reloc_offset,
 257                                         1, sizeof(reloc_offset));
 258                 if (ret) {
 259                         free(insn);
 260                         return ret;
 261                 }
 262                 ret = bytecode_push(&ctx->bytecode_reloc, node->u.load.u.ref,
 263                                         1, strlen(node->u.load.u.ref) + 1);
 264                 free(insn);
 265                 return ret;
 266         }
 267         }
 268 }
 269
 270 static
 271 int visit_node_unary(struct filter_parser_ctx *ctx, struct ir_op *node)
 272 {
 273         int ret;
 274         struct unary_op insn;
 275
 276         /* Visit child */
 277         ret = recursive_visit_gen_bytecode(ctx, node->u.unary.child);
 278         if (ret)
 279                 return ret;
 280
 281         /* Generate end of bytecode instruction */
 282         switch (node->u.unary.type) {
 283         case AST_UNARY_UNKNOWN:
 284         default:
 285                 fprintf(stderr, "[error] Unknown unary node type in %s\n",
 286                         __func__);
 287                 return -EINVAL;
 288         case AST_UNARY_PLUS:
 289                 /* Nothing to do. */
 290                 return 0;
 291         case AST_UNARY_MINUS:
 292                 insn.op = FILTER_OP_UNARY_MINUS;
 293                 return bytecode_push(&ctx->bytecode, &insn, 1, sizeof(insn));
 294         case AST_UNARY_NOT:
 295                 insn.op = FILTER_OP_UNARY_NOT;
 296                 return bytecode_push(&ctx->bytecode, &insn, 1, sizeof(insn));
 297         }
 298 }
 299
 300 /*
 301  * Binary comparator nesting is disallowed. This allows fitting into
 302  * only 2 registers.
 303  */
 304 static
 305 int visit_node_binary(struct filter_parser_ctx *ctx, struct ir_op *node)
 306 {
 307         int ret;
 308         struct binary_op insn;
 309
 310         /* Visit child */
 311         ret = recursive_visit_gen_bytecode(ctx, node->u.binary.left);
 312         if (ret)
 313                 return ret;
 314         ret = recursive_visit_gen_bytecode(ctx, node->u.binary.right);
 315         if (ret)
 316                 return ret;
 317
 318         switch (node->u.binary.type) {
 319         case AST_OP_UNKNOWN:
 320         default:
 321                 fprintf(stderr, "[error] Unknown unary node type in %s\n",
 322                         __func__);
 323                 return -EINVAL;
 324
 325         case AST_OP_AND:
 326         case AST_OP_OR:
 327                 fprintf(stderr, "[error] Unexpected logical node type in %s\n",
 328                         __func__);
 329                 return -EINVAL;
 330
 331         case AST_OP_MUL:
 332                 insn.op = FILTER_OP_MUL;
 333                 break;
 334         case AST_OP_DIV:
 335                 insn.op = FILTER_OP_DIV;
 336                 break;
 337         case AST_OP_MOD:
 338                 insn.op = FILTER_OP_MOD;
 339                 break;
 340         case AST_OP_PLUS:
 341                 insn.op = FILTER_OP_PLUS;
 342                 break;
 343         case AST_OP_MINUS:
 344                 insn.op = FILTER_OP_MINUS;
 345                 break;
 346         case AST_OP_RSHIFT:
 347                 insn.op = FILTER_OP_RSHIFT;
 348                 break;
 349         case AST_OP_LSHIFT:
 350                 insn.op = FILTER_OP_LSHIFT;
 351                 break;
 352         case AST_OP_BIN_AND:
 353                 insn.op = FILTER_OP_BIN_AND;
 354                 break;
 355         case AST_OP_BIN_OR:
 356                 insn.op = FILTER_OP_BIN_OR;
 357                 break;
 358         case AST_OP_BIN_XOR:
 359                 insn.op = FILTER_OP_BIN_XOR;
 360                 break;
 361
 362         case AST_OP_EQ:
 363                 insn.op = FILTER_OP_EQ;
 364                 break;
 365         case AST_OP_NE:
 366                 insn.op = FILTER_OP_NE;
 367                 break;
 368         case AST_OP_GT:
 369                 insn.op = FILTER_OP_GT;
 370                 break;
 371         case AST_OP_LT:
 372                 insn.op = FILTER_OP_LT;
 373                 break;
 374         case AST_OP_GE:
 375                 insn.op = FILTER_OP_GE;
 376                 break;
 377         case AST_OP_LE:
 378                 insn.op = FILTER_OP_LE;
 379                 break;
 380         }
 381         return bytecode_push(&ctx->bytecode, &insn, 1, sizeof(insn));
 382 }
 383
 384 /*
 385  * A logical op always return a s64 (1 or 0).
 386  */
 387 static
 388 int visit_node_logical(struct filter_parser_ctx *ctx, struct ir_op *node)
 389 {
 390         int ret;
 391         struct logical_op insn;
 392         uint16_t skip_offset_loc;
 393         uint16_t target_loc;
 394
 395         /* Visit left child */
 396         ret = recursive_visit_gen_bytecode(ctx, node->u.binary.left);
 397         if (ret)
 398                 return ret;
 399         /* Cast to s64 if float or field ref */
 400         if ((node->u.binary.left->data_type == IR_DATA_FIELD_REF
 401                                 || node->u.binary.left->data_type == IR_DATA_GET_CONTEXT_REF)
 402                         || node->u.binary.left->data_type == IR_DATA_FLOAT) {
 403                 struct cast_op cast_insn;
 404
 405                 if (node->u.binary.left->data_type == IR_DATA_FIELD_REF
 406                                 || node->u.binary.left->data_type == IR_DATA_GET_CONTEXT_REF) {
 407                         cast_insn.op = FILTER_OP_CAST_TO_S64;
 408                 } else {
 409                         cast_insn.op = FILTER_OP_CAST_DOUBLE_TO_S64;
 410                 }
 411                 ret = bytecode_push(&ctx->bytecode, &cast_insn,
 412                                         1, sizeof(cast_insn));
 413                 if (ret)
 414                         return ret;
 415         }
 416         switch (node->u.logical.type) {
 417         default:
 418                 fprintf(stderr, "[error] Unknown node type in %s\n",
 419                         __func__);
 420                 return -EINVAL;
 421
 422         case AST_OP_AND:
 423                 insn.op = FILTER_OP_AND;
 424                 break;
 425         case AST_OP_OR:
 426                 insn.op = FILTER_OP_OR;
 427                 break;
 428         }
 429         insn.skip_offset = (uint16_t) -1UL;     /* Temporary */
 430         ret = bytecode_push_logical(&ctx->bytecode, &insn, 1, sizeof(insn),
 431                         &skip_offset_loc);
 432         if (ret)
 433                 return ret;
 434         /* Visit right child */
 435         ret = recursive_visit_gen_bytecode(ctx, node->u.binary.right);
 436         if (ret)
 437                 return ret;
 438         /* Cast to s64 if float or field ref */
 439         if ((node->u.binary.right->data_type == IR_DATA_FIELD_REF
 440                                 || node->u.binary.right->data_type == IR_DATA_GET_CONTEXT_REF)
 441                         || node->u.binary.right->data_type == IR_DATA_FLOAT) {
 442                 struct cast_op cast_insn;
 443
 444                 if (node->u.binary.right->data_type == IR_DATA_FIELD_REF
 445                                 || node->u.binary.right->data_type == IR_DATA_GET_CONTEXT_REF) {
 446                         cast_insn.op = FILTER_OP_CAST_TO_S64;
 447                 } else {
 448                         cast_insn.op = FILTER_OP_CAST_DOUBLE_TO_S64;
 449                 }
 450                 ret = bytecode_push(&ctx->bytecode, &cast_insn,
 451                                         1, sizeof(cast_insn));
 452                 if (ret)
 453                         return ret;
 454         }
 455         /* We now know where the logical op can skip. */
 456         target_loc = (uint16_t) bytecode_get_len(&ctx->bytecode->b);
 457         ret = bytecode_patch(&ctx->bytecode,
 458                         &target_loc,                    /* Offset to jump to */
 459                         skip_offset_loc,                /* Where to patch */
 460                         sizeof(uint16_t));
 461         return ret;
 462 }
 463
 464 /*
 465  * Postorder traversal of the tree. We need the children result before
 466  * we can evaluate the parent.
 467  */
 468 static
 469 int recursive_visit_gen_bytecode(struct filter_parser_ctx *ctx,
 470                 struct ir_op *node)
 471 {
 472         switch (node->op) {
 473         case IR_OP_UNKNOWN:
 474         default:
 475                 fprintf(stderr, "[error] Unknown node type in %s\n",
 476                         __func__);
 477                 return -EINVAL;
 478
 479         case IR_OP_ROOT:
 480                 return visit_node_root(ctx, node);
 481         case IR_OP_LOAD:
 482                 return visit_node_load(ctx, node);
 483         case IR_OP_UNARY:
 484                 return visit_node_unary(ctx, node);
 485         case IR_OP_BINARY:
 486                 return visit_node_binary(ctx, node);
 487         case IR_OP_LOGICAL:
 488                 return visit_node_logical(ctx, node);
 489         }
 490 }
 491
 492 LTTNG_HIDDEN
 493 void filter_bytecode_free(struct filter_parser_ctx *ctx)
 494 {
 495         if (!ctx) {
 496                 return;
 497         }
 498
 499         if (ctx->bytecode) {
 500                 free(ctx->bytecode);
 501                 ctx->bytecode = NULL;
 502         }
 503
 504         if (ctx->bytecode_reloc) {
 505                 free(ctx->bytecode_reloc);
 506                 ctx->bytecode_reloc = NULL;
 507         }
 508 }
 509
 510 LTTNG_HIDDEN
 511 int filter_visitor_bytecode_generate(struct filter_parser_ctx *ctx)
 512 {
 513         int ret;
 514
 515         ret = bytecode_init(&ctx->bytecode);
 516         if (ret)
 517                 return ret;
 518         ret = bytecode_init(&ctx->bytecode_reloc);
 519         if (ret)
 520                 goto error;
 521         ret = recursive_visit_gen_bytecode(ctx, ctx->ir_root);
 522         if (ret)
 523                 goto error;
 524
 525         /* Finally, append symbol table to bytecode */
 526         ctx->bytecode->b.reloc_table_offset = bytecode_get_len(&ctx->bytecode->b);
 527         return bytecode_push(&ctx->bytecode, ctx->bytecode_reloc->b.data,
 528                         1, bytecode_get_len(&ctx->bytecode_reloc->b));
 529
 530 error:
 531         filter_bytecode_free(ctx);
 532         return ret;
 533 }