d0cc49556fc11560b02a8aca54cb736d2ac4291f
[lttng-tools.git] / 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.value) + 1;
177
178 insn = calloc(insn_len, 1);
179 if (!insn)
180 return -ENOMEM;
181
182 switch (node->u.load.u.string.type) {
183 case IR_LOAD_STRING_TYPE_GLOB_STAR:
184 /*
185 * We explicitly tell the interpreter here that
186 * this load is a full star globbing pattern so
187 * that the appropriate matching function can be
188 * called. Also, see comment below.
189 */
190 insn->op = FILTER_OP_LOAD_STAR_GLOB_STRING;
191 break;
192 default:
193 /*
194 * This is the "legacy" string, which includes
195 * star globbing patterns with a star only at
196 * the end. Both "plain" and "star at the end"
197 * literal strings are handled at the same place
198 * by the tracer's filter bytecode interpreter,
199 * whereas full star globbing patterns (stars
200 * can be anywhere in the string) is a special
201 * case.
202 */
203 insn->op = FILTER_OP_LOAD_STRING;
204 break;
205 }
206
207 strcpy(insn->data, node->u.load.u.string.value);
208 ret = bytecode_push(&ctx->bytecode, insn, 1, insn_len);
209 free(insn);
210 return ret;
211 }
212 case IR_DATA_NUMERIC:
213 {
214 struct load_op *insn;
215 uint32_t insn_len = sizeof(struct load_op)
216 + sizeof(struct literal_numeric);
217
218 insn = calloc(insn_len, 1);
219 if (!insn)
220 return -ENOMEM;
221 insn->op = FILTER_OP_LOAD_S64;
222 memcpy(insn->data, &node->u.load.u.num, sizeof(int64_t));
223 ret = bytecode_push(&ctx->bytecode, insn, 1, insn_len);
224 free(insn);
225 return ret;
226 }
227 case IR_DATA_FLOAT:
228 {
229 struct load_op *insn;
230 uint32_t insn_len = sizeof(struct load_op)
231 + sizeof(struct literal_double);
232
233 insn = calloc(insn_len, 1);
234 if (!insn)
235 return -ENOMEM;
236 insn->op = FILTER_OP_LOAD_DOUBLE;
237 memcpy(insn->data, &node->u.load.u.flt, sizeof(double));
238 ret = bytecode_push(&ctx->bytecode, insn, 1, insn_len);
239 free(insn);
240 return ret;
241 }
242 case IR_DATA_FIELD_REF: /* fall-through */
243 case IR_DATA_GET_CONTEXT_REF:
244 {
245 struct load_op *insn;
246 uint32_t insn_len = sizeof(struct load_op)
247 + sizeof(struct field_ref);
248 struct field_ref ref_offset;
249 uint32_t reloc_offset_u32;
250 uint16_t reloc_offset;
251
252 insn = calloc(insn_len, 1);
253 if (!insn)
254 return -ENOMEM;
255 switch(node->data_type) {
256 case IR_DATA_FIELD_REF:
257 insn->op = FILTER_OP_LOAD_FIELD_REF;
258 break;
259 case IR_DATA_GET_CONTEXT_REF:
260 insn->op = FILTER_OP_GET_CONTEXT_REF;
261 break;
262 default:
263 free(insn);
264 return -EINVAL;
265 }
266 ref_offset.offset = (uint16_t) -1U;
267 memcpy(insn->data, &ref_offset, sizeof(ref_offset));
268 /* reloc_offset points to struct load_op */
269 reloc_offset_u32 = bytecode_get_len(&ctx->bytecode->b);
270 if (reloc_offset_u32 > LTTNG_FILTER_MAX_LEN - 1) {
271 free(insn);
272 return -EINVAL;
273 }
274 reloc_offset = (uint16_t) reloc_offset_u32;
275 ret = bytecode_push(&ctx->bytecode, insn, 1, insn_len);
276 if (ret) {
277 free(insn);
278 return ret;
279 }
280 /* append reloc */
281 ret = bytecode_push(&ctx->bytecode_reloc, &reloc_offset,
282 1, sizeof(reloc_offset));
283 if (ret) {
284 free(insn);
285 return ret;
286 }
287 ret = bytecode_push(&ctx->bytecode_reloc, node->u.load.u.ref,
288 1, strlen(node->u.load.u.ref) + 1);
289 free(insn);
290 return ret;
291 }
292 }
293 }
294
295 static
296 int visit_node_unary(struct filter_parser_ctx *ctx, struct ir_op *node)
297 {
298 int ret;
299 struct unary_op insn;
300
301 /* Visit child */
302 ret = recursive_visit_gen_bytecode(ctx, node->u.unary.child);
303 if (ret)
304 return ret;
305
306 /* Generate end of bytecode instruction */
307 switch (node->u.unary.type) {
308 case AST_UNARY_UNKNOWN:
309 default:
310 fprintf(stderr, "[error] Unknown unary node type in %s\n",
311 __func__);
312 return -EINVAL;
313 case AST_UNARY_PLUS:
314 /* Nothing to do. */
315 return 0;
316 case AST_UNARY_MINUS:
317 insn.op = FILTER_OP_UNARY_MINUS;
318 return bytecode_push(&ctx->bytecode, &insn, 1, sizeof(insn));
319 case AST_UNARY_NOT:
320 insn.op = FILTER_OP_UNARY_NOT;
321 return bytecode_push(&ctx->bytecode, &insn, 1, sizeof(insn));
322 }
323 }
324
325 /*
326 * Binary comparator nesting is disallowed. This allows fitting into
327 * only 2 registers.
328 */
329 static
330 int visit_node_binary(struct filter_parser_ctx *ctx, struct ir_op *node)
331 {
332 int ret;
333 struct binary_op insn;
334
335 /* Visit child */
336 ret = recursive_visit_gen_bytecode(ctx, node->u.binary.left);
337 if (ret)
338 return ret;
339 ret = recursive_visit_gen_bytecode(ctx, node->u.binary.right);
340 if (ret)
341 return ret;
342
343 switch (node->u.binary.type) {
344 case AST_OP_UNKNOWN:
345 default:
346 fprintf(stderr, "[error] Unknown unary node type in %s\n",
347 __func__);
348 return -EINVAL;
349
350 case AST_OP_AND:
351 case AST_OP_OR:
352 fprintf(stderr, "[error] Unexpected logical node type in %s\n",
353 __func__);
354 return -EINVAL;
355
356 case AST_OP_MUL:
357 insn.op = FILTER_OP_MUL;
358 break;
359 case AST_OP_DIV:
360 insn.op = FILTER_OP_DIV;
361 break;
362 case AST_OP_MOD:
363 insn.op = FILTER_OP_MOD;
364 break;
365 case AST_OP_PLUS:
366 insn.op = FILTER_OP_PLUS;
367 break;
368 case AST_OP_MINUS:
369 insn.op = FILTER_OP_MINUS;
370 break;
371 case AST_OP_RSHIFT:
372 insn.op = FILTER_OP_RSHIFT;
373 break;
374 case AST_OP_LSHIFT:
375 insn.op = FILTER_OP_LSHIFT;
376 break;
377 case AST_OP_BIN_AND:
378 insn.op = FILTER_OP_BIN_AND;
379 break;
380 case AST_OP_BIN_OR:
381 insn.op = FILTER_OP_BIN_OR;
382 break;
383 case AST_OP_BIN_XOR:
384 insn.op = FILTER_OP_BIN_XOR;
385 break;
386
387 case AST_OP_EQ:
388 insn.op = FILTER_OP_EQ;
389 break;
390 case AST_OP_NE:
391 insn.op = FILTER_OP_NE;
392 break;
393 case AST_OP_GT:
394 insn.op = FILTER_OP_GT;
395 break;
396 case AST_OP_LT:
397 insn.op = FILTER_OP_LT;
398 break;
399 case AST_OP_GE:
400 insn.op = FILTER_OP_GE;
401 break;
402 case AST_OP_LE:
403 insn.op = FILTER_OP_LE;
404 break;
405 }
406 return bytecode_push(&ctx->bytecode, &insn, 1, sizeof(insn));
407 }
408
409 /*
410 * A logical op always return a s64 (1 or 0).
411 */
412 static
413 int visit_node_logical(struct filter_parser_ctx *ctx, struct ir_op *node)
414 {
415 int ret;
416 struct logical_op insn;
417 uint16_t skip_offset_loc;
418 uint16_t target_loc;
419
420 /* Visit left child */
421 ret = recursive_visit_gen_bytecode(ctx, node->u.binary.left);
422 if (ret)
423 return ret;
424 /* Cast to s64 if float or field ref */
425 if ((node->u.binary.left->data_type == IR_DATA_FIELD_REF
426 || node->u.binary.left->data_type == IR_DATA_GET_CONTEXT_REF)
427 || node->u.binary.left->data_type == IR_DATA_FLOAT) {
428 struct cast_op cast_insn;
429
430 if (node->u.binary.left->data_type == IR_DATA_FIELD_REF
431 || node->u.binary.left->data_type == IR_DATA_GET_CONTEXT_REF) {
432 cast_insn.op = FILTER_OP_CAST_TO_S64;
433 } else {
434 cast_insn.op = FILTER_OP_CAST_DOUBLE_TO_S64;
435 }
436 ret = bytecode_push(&ctx->bytecode, &cast_insn,
437 1, sizeof(cast_insn));
438 if (ret)
439 return ret;
440 }
441 switch (node->u.logical.type) {
442 default:
443 fprintf(stderr, "[error] Unknown node type in %s\n",
444 __func__);
445 return -EINVAL;
446
447 case AST_OP_AND:
448 insn.op = FILTER_OP_AND;
449 break;
450 case AST_OP_OR:
451 insn.op = FILTER_OP_OR;
452 break;
453 }
454 insn.skip_offset = (uint16_t) -1UL; /* Temporary */
455 ret = bytecode_push_logical(&ctx->bytecode, &insn, 1, sizeof(insn),
456 &skip_offset_loc);
457 if (ret)
458 return ret;
459 /* Visit right child */
460 ret = recursive_visit_gen_bytecode(ctx, node->u.binary.right);
461 if (ret)
462 return ret;
463 /* Cast to s64 if float or field ref */
464 if ((node->u.binary.right->data_type == IR_DATA_FIELD_REF
465 || node->u.binary.right->data_type == IR_DATA_GET_CONTEXT_REF)
466 || node->u.binary.right->data_type == IR_DATA_FLOAT) {
467 struct cast_op cast_insn;
468
469 if (node->u.binary.right->data_type == IR_DATA_FIELD_REF
470 || node->u.binary.right->data_type == IR_DATA_GET_CONTEXT_REF) {
471 cast_insn.op = FILTER_OP_CAST_TO_S64;
472 } else {
473 cast_insn.op = FILTER_OP_CAST_DOUBLE_TO_S64;
474 }
475 ret = bytecode_push(&ctx->bytecode, &cast_insn,
476 1, sizeof(cast_insn));
477 if (ret)
478 return ret;
479 }
480 /* We now know where the logical op can skip. */
481 target_loc = (uint16_t) bytecode_get_len(&ctx->bytecode->b);
482 ret = bytecode_patch(&ctx->bytecode,
483 &target_loc, /* Offset to jump to */
484 skip_offset_loc, /* Where to patch */
485 sizeof(uint16_t));
486 return ret;
487 }
488
489 /*
490 * Postorder traversal of the tree. We need the children result before
491 * we can evaluate the parent.
492 */
493 static
494 int recursive_visit_gen_bytecode(struct filter_parser_ctx *ctx,
495 struct ir_op *node)
496 {
497 switch (node->op) {
498 case IR_OP_UNKNOWN:
499 default:
500 fprintf(stderr, "[error] Unknown node type in %s\n",
501 __func__);
502 return -EINVAL;
503
504 case IR_OP_ROOT:
505 return visit_node_root(ctx, node);
506 case IR_OP_LOAD:
507 return visit_node_load(ctx, node);
508 case IR_OP_UNARY:
509 return visit_node_unary(ctx, node);
510 case IR_OP_BINARY:
511 return visit_node_binary(ctx, node);
512 case IR_OP_LOGICAL:
513 return visit_node_logical(ctx, node);
514 }
515 }
516
517 LTTNG_HIDDEN
518 void filter_bytecode_free(struct filter_parser_ctx *ctx)
519 {
520 if (!ctx) {
521 return;
522 }
523
524 if (ctx->bytecode) {
525 free(ctx->bytecode);
526 ctx->bytecode = NULL;
527 }
528
529 if (ctx->bytecode_reloc) {
530 free(ctx->bytecode_reloc);
531 ctx->bytecode_reloc = NULL;
532 }
533 }
534
535 LTTNG_HIDDEN
536 int filter_visitor_bytecode_generate(struct filter_parser_ctx *ctx)
537 {
538 int ret;
539
540 ret = bytecode_init(&ctx->bytecode);
541 if (ret)
542 return ret;
543 ret = bytecode_init(&ctx->bytecode_reloc);
544 if (ret)
545 goto error;
546 ret = recursive_visit_gen_bytecode(ctx, ctx->ir_root);
547 if (ret)
548 goto error;
549
550 /* Finally, append symbol table to bytecode */
551 ctx->bytecode->b.reloc_table_offset = bytecode_get_len(&ctx->bytecode->b);
552 return bytecode_push(&ctx->bytecode, ctx->bytecode_reloc->b.data,
553 1, bytecode_get_len(&ctx->bytecode_reloc->b));
554
555 error:
556 filter_bytecode_free(ctx);
557 return ret;
558 }
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