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 "align.h"
  26 #include "filter-bytecode.h"
  27 #include "filter-ir.h"
  28 #include "filter-ast.h"
  29
  30 #ifndef max_t
  31 #define max_t(type, a, b)       ((type) ((a) > (b) ? (a) : (b)))
  32 #endif
  33
  34 //#define INIT_ALLOC_SIZE               PAGE_SIZE
  35 #define INIT_ALLOC_SIZE         4
  36
  37 static
  38 int recursive_visit_gen_bytecode(struct filter_parser_ctx *ctx,
  39                 struct ir_op *node);
  40
  41 static
  42 int bytecode_init(struct lttng_filter_bytecode_alloc **fb)
  43 {
  44         *fb = calloc(sizeof(struct lttng_filter_bytecode_alloc) + INIT_ALLOC_SIZE, 1);
  45         if (!*fb) {
  46                 return -ENOMEM;
  47         } else {
  48                 (*fb)->alloc_len = INIT_ALLOC_SIZE;
  49                 return 0;
  50         }
  51 }
  52
  53 static
  54 int32_t bytecode_reserve(struct lttng_filter_bytecode_alloc **fb, uint32_t align, uint32_t len)
  55 {
  56         int32_t ret;
  57         uint32_t padding = offset_align((*fb)->b.len, align);
  58
  59         if ((*fb)->b.len + padding + len > (*fb)->alloc_len) {
  60                 uint32_t new_len =
  61                         max_t(uint32_t, (*fb)->b.len + padding + len,
  62                                 (*fb)->alloc_len << 1);
  63                 uint32_t old_len = (*fb)->alloc_len;
  64
  65                 if (new_len > 0xFFFF)
  66                         return -EINVAL;
  67                 *fb = realloc(*fb, sizeof(struct lttng_filter_bytecode_alloc) + new_len);
  68                 if (!*fb)
  69                         return -ENOMEM;
  70                 memset(&(*fb)->b.data[old_len], 0, new_len - old_len);
  71                 (*fb)->alloc_len = new_len;
  72         }
  73         (*fb)->b.len += padding;
  74         ret = (*fb)->b.len;
  75         (*fb)->b.len += len;
  76         return ret;
  77 }
  78
  79 static
  80 int bytecode_push(struct lttng_filter_bytecode_alloc **fb, const void *data,
  81                 uint32_t align, uint32_t len)
  82 {
  83         int32_t offset;
  84
  85         offset = bytecode_reserve(fb, align, len);
  86         if (offset < 0)
  87                 return offset;
  88         memcpy(&(*fb)->b.data[offset], data, len);
  89         return 0;
  90 }
  91
  92 static
  93 int bytecode_push_logical(struct lttng_filter_bytecode_alloc **fb,
  94                 struct logical_op *data,
  95                 uint32_t align, uint32_t len,
  96                 uint16_t *skip_offset)
  97 {
  98         int32_t offset;
  99
 100         offset = bytecode_reserve(fb, align, len);
 101         if (offset < 0)
 102                 return offset;
 103         memcpy(&(*fb)->b.data[offset], data, len);
 104         *skip_offset =
 105                 (void *) &((struct logical_op *) &(*fb)->b.data[offset])->skip_offset
 106                         - (void *) &(*fb)->b.data[0];
 107         return 0;
 108 }
 109
 110 static
 111 int bytecode_patch(struct lttng_filter_bytecode_alloc **fb,
 112                 const void *data,
 113                 uint16_t offset,
 114                 uint32_t len)
 115 {
 116         if (offset >= (*fb)->b.len) {
 117                 return -EINVAL;
 118         }
 119         memcpy(&(*fb)->b.data[offset], data, len);
 120         return 0;
 121 }
 122
 123 static
 124 int visit_node_root(struct filter_parser_ctx *ctx, struct ir_op *node)
 125 {
 126         int ret;
 127         struct return_op insn;
 128
 129         /* Visit child */
 130         ret = recursive_visit_gen_bytecode(ctx, node->u.root.child);
 131         if (ret)
 132                 return ret;
 133
 134         /* Generate end of bytecode instruction */
 135         insn.op = FILTER_OP_RETURN;
 136         return bytecode_push(&ctx->bytecode, &insn, 1, sizeof(insn));
 137 }
 138
 139 static
 140 int visit_node_load(struct filter_parser_ctx *ctx, struct ir_op *node)
 141 {
 142         int ret;
 143
 144         switch (node->data_type) {
 145         case IR_DATA_UNKNOWN:
 146         default:
 147                 fprintf(stderr, "[error] Unknown data type in %s\n",
 148                         __func__);
 149                 return -EINVAL;
 150
 151         case IR_DATA_STRING:
 152         {
 153                 struct load_op *insn;
 154                 uint32_t insn_len = sizeof(struct load_op)
 155                         + strlen(node->u.load.u.string) + 1;
 156
 157                 insn = calloc(insn_len, 1);
 158                 if (!insn)
 159                         return -ENOMEM;
 160                 insn->op = FILTER_OP_LOAD_STRING;
 161                 strcpy(insn->data, node->u.load.u.string);
 162                 ret = bytecode_push(&ctx->bytecode, insn, 1, insn_len);
 163                 free(insn);
 164                 return ret;
 165         }
 166         case IR_DATA_NUMERIC:
 167         {
 168                 struct load_op *insn;
 169                 uint32_t insn_len = sizeof(struct load_op)
 170                         + sizeof(struct literal_numeric);
 171
 172                 insn = calloc(insn_len, 1);
 173                 if (!insn)
 174                         return -ENOMEM;
 175                 insn->op = FILTER_OP_LOAD_S64;
 176                 *(int64_t *) insn->data = node->u.load.u.num;
 177                 ret = bytecode_push(&ctx->bytecode, insn, 1, insn_len);
 178                 free(insn);
 179                 return ret;
 180         }
 181         case IR_DATA_FLOAT:
 182         {
 183                 struct load_op *insn;
 184                 uint32_t insn_len = sizeof(struct load_op)
 185                         + sizeof(struct literal_double);
 186
 187                 insn = calloc(insn_len, 1);
 188                 if (!insn)
 189                         return -ENOMEM;
 190                 insn->op = FILTER_OP_LOAD_DOUBLE;
 191                 *(double *) insn->data = node->u.load.u.flt;
 192                 ret = bytecode_push(&ctx->bytecode, insn, 1, insn_len);
 193                 free(insn);
 194                 return ret;
 195         }
 196         case IR_DATA_FIELD_REF:
 197         {
 198                 struct load_op *insn;
 199                 uint32_t insn_len = sizeof(struct load_op)
 200                         + sizeof(struct field_ref);
 201                 struct field_ref ref_offset;
 202                 uint16_t reloc_offset;
 203
 204                 insn = calloc(insn_len, 1);
 205                 if (!insn)
 206                         return -ENOMEM;
 207                 insn->op = FILTER_OP_LOAD_FIELD_REF;
 208                 ref_offset.offset = (uint16_t) -1U;
 209                 memcpy(insn->data, &ref_offset, sizeof(ref_offset));
 210                 /* reloc_offset points to struct load_op */
 211                 reloc_offset = bytecode_get_len(&ctx->bytecode->b);
 212                 ret = bytecode_push(&ctx->bytecode, insn, 1, insn_len);
 213                 if (ret) {
 214                         free(insn);
 215                         return ret;
 216                 }
 217                 /* append reloc */
 218                 ret = bytecode_push(&ctx->bytecode_reloc, &reloc_offset,
 219                                         1, sizeof(reloc_offset));
 220                 if (ret) {
 221                         free(insn);
 222                         return ret;
 223                 }
 224                 ret = bytecode_push(&ctx->bytecode_reloc, node->u.load.u.ref,
 225                                         1, strlen(node->u.load.u.ref) + 1);
 226                 free(insn);
 227                 return ret;
 228         }
 229         }
 230 }
 231
 232 static
 233 int visit_node_unary(struct filter_parser_ctx *ctx, struct ir_op *node)
 234 {
 235         int ret;
 236         struct unary_op insn;
 237
 238         /* Visit child */
 239         ret = recursive_visit_gen_bytecode(ctx, node->u.unary.child);
 240         if (ret)
 241                 return ret;
 242
 243         /* Generate end of bytecode instruction */
 244         switch (node->u.unary.type) {
 245         case AST_UNARY_UNKNOWN:
 246         default:
 247                 fprintf(stderr, "[error] Unknown unary node type in %s\n",
 248                         __func__);
 249                 return -EINVAL;
 250         case AST_UNARY_PLUS:
 251                 /* Nothing to do. */
 252                 return 0;
 253         case AST_UNARY_MINUS:
 254                 insn.op = FILTER_OP_UNARY_MINUS;
 255                 return bytecode_push(&ctx->bytecode, &insn, 1, sizeof(insn));
 256         case AST_UNARY_NOT:
 257                 insn.op = FILTER_OP_UNARY_NOT;
 258                 return bytecode_push(&ctx->bytecode, &insn, 1, sizeof(insn));
 259         }
 260 }
 261
 262 /*
 263  * Binary comparator nesting is disallowed. This allows fitting into
 264  * only 2 registers.
 265  */
 266 static
 267 int visit_node_binary(struct filter_parser_ctx *ctx, struct ir_op *node)
 268 {
 269         int ret;
 270         struct binary_op insn;
 271
 272         /* Visit child */
 273         ret = recursive_visit_gen_bytecode(ctx, node->u.binary.left);
 274         if (ret)
 275                 return ret;
 276         ret = recursive_visit_gen_bytecode(ctx, node->u.binary.right);
 277         if (ret)
 278                 return ret;
 279
 280         switch (node->u.binary.type) {
 281         case AST_OP_UNKNOWN:
 282         default:
 283                 fprintf(stderr, "[error] Unknown unary node type in %s\n",
 284                         __func__);
 285                 return -EINVAL;
 286
 287         case AST_OP_AND:
 288         case AST_OP_OR:
 289                 fprintf(stderr, "[error] Unexpected logical node type in %s\n",
 290                         __func__);
 291                 return -EINVAL;
 292
 293         case AST_OP_MUL:
 294                 insn.op = FILTER_OP_MUL;
 295                 break;
 296         case AST_OP_DIV:
 297                 insn.op = FILTER_OP_DIV;
 298                 break;
 299         case AST_OP_MOD:
 300                 insn.op = FILTER_OP_MOD;
 301                 break;
 302         case AST_OP_PLUS:
 303                 insn.op = FILTER_OP_PLUS;
 304                 break;
 305         case AST_OP_MINUS:
 306                 insn.op = FILTER_OP_MINUS;
 307                 break;
 308         case AST_OP_RSHIFT:
 309                 insn.op = FILTER_OP_RSHIFT;
 310                 break;
 311         case AST_OP_LSHIFT:
 312                 insn.op = FILTER_OP_LSHIFT;
 313                 break;
 314         case AST_OP_BIN_AND:
 315                 insn.op = FILTER_OP_BIN_AND;
 316                 break;
 317         case AST_OP_BIN_OR:
 318                 insn.op = FILTER_OP_BIN_OR;
 319                 break;
 320         case AST_OP_BIN_XOR:
 321                 insn.op = FILTER_OP_BIN_XOR;
 322                 break;
 323
 324         case AST_OP_EQ:
 325                 insn.op = FILTER_OP_EQ;
 326                 break;
 327         case AST_OP_NE:
 328                 insn.op = FILTER_OP_NE;
 329                 break;
 330         case AST_OP_GT:
 331                 insn.op = FILTER_OP_GT;
 332                 break;
 333         case AST_OP_LT:
 334                 insn.op = FILTER_OP_LT;
 335                 break;
 336         case AST_OP_GE:
 337                 insn.op = FILTER_OP_GE;
 338                 break;
 339         case AST_OP_LE:
 340                 insn.op = FILTER_OP_LE;
 341                 break;
 342         }
 343         return bytecode_push(&ctx->bytecode, &insn, 1, sizeof(insn));
 344 }
 345
 346 /*
 347  * A logical op always return a s64 (1 or 0).
 348  */
 349 static
 350 int visit_node_logical(struct filter_parser_ctx *ctx, struct ir_op *node)
 351 {
 352         int ret;
 353         struct logical_op insn;
 354         uint16_t skip_offset_loc;
 355         uint16_t target_loc;
 356
 357         /* Visit left child */
 358         ret = recursive_visit_gen_bytecode(ctx, node->u.binary.left);
 359         if (ret)
 360                 return ret;
 361         /* Cast to s64 if float or field ref */
 362         if (node->u.binary.left->data_type == IR_DATA_FIELD_REF
 363                         || node->u.binary.left->data_type == IR_DATA_FLOAT) {
 364                 struct cast_op cast_insn;
 365
 366                 if (node->u.binary.left->data_type == IR_DATA_FIELD_REF) {
 367                         cast_insn.op = FILTER_OP_CAST_TO_S64;
 368                 } else {
 369                         cast_insn.op = FILTER_OP_CAST_DOUBLE_TO_S64;
 370                 }
 371                 ret = bytecode_push(&ctx->bytecode, &cast_insn,
 372                                         1, sizeof(cast_insn));
 373                 if (ret)
 374                         return ret;
 375         }
 376         switch (node->u.logical.type) {
 377         default:
 378                 fprintf(stderr, "[error] Unknown node type in %s\n",
 379                         __func__);
 380                 return -EINVAL;
 381
 382         case AST_OP_AND:
 383                 insn.op = FILTER_OP_AND;
 384                 break;
 385         case AST_OP_OR:
 386                 insn.op = FILTER_OP_OR;
 387                 break;
 388         }
 389         insn.skip_offset = (uint16_t) -1UL;     /* Temporary */
 390         ret = bytecode_push_logical(&ctx->bytecode, &insn, 1, sizeof(insn),
 391                         &skip_offset_loc);
 392         if (ret)
 393                 return ret;
 394         /* Visit right child */
 395         ret = recursive_visit_gen_bytecode(ctx, node->u.binary.right);
 396         if (ret)
 397                 return ret;
 398         /* Cast to s64 if float or field ref */
 399         if (node->u.binary.right->data_type == IR_DATA_FIELD_REF
 400                         || node->u.binary.right->data_type == IR_DATA_FLOAT) {
 401                 struct cast_op cast_insn;
 402
 403                 if (node->u.binary.right->data_type == IR_DATA_FIELD_REF) {
 404                         cast_insn.op = FILTER_OP_CAST_TO_S64;
 405                 } else {
 406                         cast_insn.op = FILTER_OP_CAST_DOUBLE_TO_S64;
 407                 }
 408                 ret = bytecode_push(&ctx->bytecode, &cast_insn,
 409                                         1, sizeof(cast_insn));
 410                 if (ret)
 411                         return ret;
 412         }
 413         /* We now know where the logical op can skip. */
 414         target_loc = (uint16_t) bytecode_get_len(&ctx->bytecode->b);
 415         ret = bytecode_patch(&ctx->bytecode,
 416                         &target_loc,                    /* Offset to jump to */
 417                         skip_offset_loc,                /* Where to patch */
 418                         sizeof(uint16_t));
 419         return ret;
 420 }
 421
 422 /*
 423  * Postorder traversal of the tree. We need the children result before
 424  * we can evaluate the parent.
 425  */
 426 static
 427 int recursive_visit_gen_bytecode(struct filter_parser_ctx *ctx,
 428                 struct ir_op *node)
 429 {
 430         switch (node->op) {
 431         case IR_OP_UNKNOWN:
 432         default:
 433                 fprintf(stderr, "[error] Unknown node type in %s\n",
 434                         __func__);
 435                 return -EINVAL;
 436
 437         case IR_OP_ROOT:
 438                 return visit_node_root(ctx, node);
 439         case IR_OP_LOAD:
 440                 return visit_node_load(ctx, node);
 441         case IR_OP_UNARY:
 442                 return visit_node_unary(ctx, node);
 443         case IR_OP_BINARY:
 444                 return visit_node_binary(ctx, node);
 445         case IR_OP_LOGICAL:
 446                 return visit_node_logical(ctx, node);
 447         }
 448 }
 449
 450 __attribute__((visibility("hidden")))
 451 void filter_bytecode_free(struct filter_parser_ctx *ctx)
 452 {
 453         free(ctx->bytecode);
 454         ctx->bytecode = NULL;
 455         free(ctx->bytecode_reloc);
 456         ctx->bytecode_reloc = NULL;
 457 }
 458
 459 __attribute__((visibility("hidden")))
 460 int filter_visitor_bytecode_generate(struct filter_parser_ctx *ctx)
 461 {
 462         int ret;
 463
 464         ret = bytecode_init(&ctx->bytecode);
 465         if (ret)
 466                 return ret;
 467         ret = bytecode_init(&ctx->bytecode_reloc);
 468         if (ret)
 469                 goto error;
 470         ret = recursive_visit_gen_bytecode(ctx, ctx->ir_root);
 471         if (ret)
 472                 goto error;
 473
 474         /* Finally, append symbol table to bytecode */
 475         ctx->bytecode->b.reloc_table_offset = bytecode_get_len(&ctx->bytecode->b);
 476         return bytecode_push(&ctx->bytecode, ctx->bytecode_reloc->b.data,
 477                         1, bytecode_get_len(&ctx->bytecode_reloc->b));
 478
 479 error:
 480         filter_bytecode_free(ctx);
 481         return ret;
 482 }