1 /*===- GCDAProfiling.c - Support library for GCDA file emission -----------===*\
2 |*
3 |* The LLVM Compiler Infrastructure
4 |*
5 |* This file is distributed under the University of Illinois Open Source
6 |* License. See LICENSE.TXT for details.
7 |*
8 |*===----------------------------------------------------------------------===*|
9 |*
10 |* This file implements the call back routines for the gcov profiling
11 |* instrumentation pass. Link against this library when running code through
12 |* the -insert-gcov-profiling LLVM pass.
13 |*
14 |* We emit files in a corrupt version of GCOV's "gcda" file format. These files
15 |* are only close enough that LCOV will happily parse them. Anything that lcov
16 |* ignores is missing.
17 |*
18 |* TODO: gcov is multi-process safe by having each exit open the existing file
19 |* and append to it. We'd like to achieve that and be thread-safe too.
20 |*
21 \*===----------------------------------------------------------------------===*/
22
23 #include <errno.h>
24 #include <fcntl.h>
25 #include <stdio.h>
26 #include <stdlib.h>
27 #include <string.h>
28 #include <sys/mman.h>
29 #ifdef _WIN32
30 #include <direct.h>
31 #endif
32
33 #define I386_FREEBSD (defined(__FreeBSD__) && defined(__i386__))
34
35 #if !I386_FREEBSD
36 #include <sys/stat.h>
37 #include <sys/types.h>
38 #endif
39
40 #if !defined(_MSC_VER) && !I386_FREEBSD
41 #include <stdint.h>
42 #endif
43
44 #if defined(_MSC_VER)
45 typedef unsigned int uint32_t;
46 typedef unsigned long long uint64_t;
47 #elif I386_FREEBSD
48 /* System headers define 'size_t' incorrectly on x64 FreeBSD (prior to
49 * FreeBSD 10, r232261) when compiled in 32-bit mode.
50 */
51 typedef unsigned char uint8_t;
52 typedef unsigned int uint32_t;
53 typedef unsigned long long uint64_t;
54 int mkdir(const char*, unsigned short);
55 #endif
56
57 /* #define DEBUG_GCDAPROFILING */
58
59 /*
60 * --- GCOV file format I/O primitives ---
61 */
62
63 /*
64 * The current file name we're outputting. Used primarily for error logging.
65 */
66 static char *filename = NULL;
67
68 /*
69 * The current file we're outputting.
70 */
71 static FILE *output_file = NULL;
72
73 /*
74 * Buffer that we write things into.
75 */
76 #define WRITE_BUFFER_SIZE (128 * 1024)
77 static char *write_buffer = NULL;
78 static uint64_t cur_buffer_size = 0;
79 static uint64_t cur_pos = 0;
80 static uint64_t file_size = 0;
81 static int new_file = 0;
82 static int fd = -1;
83
84 /*
85 * A list of functions to write out the data.
86 */
87 typedef void (*writeout_fn)();
88
89 struct writeout_fn_node {
90 writeout_fn fn;
91 struct writeout_fn_node *next;
92 };
93
94 static struct writeout_fn_node *writeout_fn_head = NULL;
95 static struct writeout_fn_node *writeout_fn_tail = NULL;
96
97 /*
98 * A list of flush functions that our __gcov_flush() function should call.
99 */
100 typedef void (*flush_fn)();
101
102 struct flush_fn_node {
103 flush_fn fn;
104 struct flush_fn_node *next;
105 };
106
107 static struct flush_fn_node *flush_fn_head = NULL;
108 static struct flush_fn_node *flush_fn_tail = NULL;
109
resize_write_buffer(uint64_t size)110 static void resize_write_buffer(uint64_t size) {
111 if (!new_file) return;
112 size += cur_pos;
113 if (size <= cur_buffer_size) return;
114 size = (size - 1) / WRITE_BUFFER_SIZE + 1;
115 size *= WRITE_BUFFER_SIZE;
116 write_buffer = realloc(write_buffer, size);
117 cur_buffer_size = size;
118 }
119
write_bytes(const char * s,size_t len)120 static void write_bytes(const char *s, size_t len) {
121 resize_write_buffer(len);
122 memcpy(&write_buffer[cur_pos], s, len);
123 cur_pos += len;
124 }
125
write_32bit_value(uint32_t i)126 static void write_32bit_value(uint32_t i) {
127 write_bytes((char*)&i, 4);
128 }
129
write_64bit_value(uint64_t i)130 static void write_64bit_value(uint64_t i) {
131 write_bytes((char*)&i, 8);
132 }
133
length_of_string(const char * s)134 static uint32_t length_of_string(const char *s) {
135 return (strlen(s) / 4) + 1;
136 }
137
write_string(const char * s)138 static void write_string(const char *s) {
139 uint32_t len = length_of_string(s);
140 write_32bit_value(len);
141 write_bytes(s, strlen(s));
142 write_bytes("\0\0\0\0", 4 - (strlen(s) % 4));
143 }
144
read_32bit_value()145 static uint32_t read_32bit_value() {
146 uint32_t val;
147
148 if (new_file)
149 return (uint32_t)-1;
150
151 val = *(uint32_t*)&write_buffer[cur_pos];
152 cur_pos += 4;
153 return val;
154 }
155
read_64bit_value()156 static uint64_t read_64bit_value() {
157 uint64_t val;
158
159 if (new_file)
160 return (uint64_t)-1;
161
162 val = *(uint64_t*)&write_buffer[cur_pos];
163 cur_pos += 8;
164 return val;
165 }
166
mangle_filename(const char * orig_filename)167 static char *mangle_filename(const char *orig_filename) {
168 char *new_filename;
169 size_t filename_len, prefix_len;
170 int prefix_strip;
171 int level = 0;
172 const char *fname, *ptr;
173 const char *prefix = getenv("GCOV_PREFIX");
174 const char *prefix_strip_str = getenv("GCOV_PREFIX_STRIP");
175
176 if (prefix == NULL || prefix[0] == '\0')
177 return strdup(orig_filename);
178
179 if (prefix_strip_str) {
180 prefix_strip = atoi(prefix_strip_str);
181
182 /* Negative GCOV_PREFIX_STRIP values are ignored */
183 if (prefix_strip < 0)
184 prefix_strip = 0;
185 } else {
186 prefix_strip = 0;
187 }
188
189 fname = orig_filename;
190 for (level = 0, ptr = fname + 1; level < prefix_strip; ++ptr) {
191 if (*ptr == '\0')
192 break;
193 if (*ptr != '/')
194 continue;
195 fname = ptr;
196 ++level;
197 }
198
199 filename_len = strlen(fname);
200 prefix_len = strlen(prefix);
201 new_filename = malloc(prefix_len + 1 + filename_len + 1);
202 memcpy(new_filename, prefix, prefix_len);
203
204 if (prefix[prefix_len - 1] != '/')
205 new_filename[prefix_len++] = '/';
206 memcpy(new_filename + prefix_len, fname, filename_len + 1);
207
208 return new_filename;
209 }
210
recursive_mkdir(char * path)211 static void recursive_mkdir(char *path) {
212 int i;
213
214 for (i = 1; path[i] != '\0'; ++i) {
215 if (path[i] != '/') continue;
216 path[i] = '\0';
217 #ifdef _WIN32
218 _mkdir(path);
219 #else
220 mkdir(path, 0755); /* Some of these will fail, ignore it. */
221 #endif
222 path[i] = '/';
223 }
224 }
225
map_file()226 static int map_file() {
227 fseek(output_file, 0L, SEEK_END);
228 file_size = ftell(output_file);
229
230 /* A size of 0 is invalid to `mmap'. Return a fail here, but don't issue an
231 * error message because it should "just work" for the user. */
232 if (file_size == 0)
233 return -1;
234
235 write_buffer = mmap(0, file_size, PROT_READ | PROT_WRITE,
236 MAP_FILE | MAP_SHARED, fd, 0);
237 if (write_buffer == (void *)-1) {
238 int errnum = errno;
239 fprintf(stderr, "profiling: %s: cannot map: %s\n", filename,
240 strerror(errnum));
241 return -1;
242 }
243 return 0;
244 }
245
unmap_file()246 static void unmap_file() {
247 #if !defined(__minix)
248 if (msync(write_buffer, file_size, MS_SYNC) == -1) {
249 int errnum = errno;
250 fprintf(stderr, "profiling: %s: cannot msync: %s\n", filename,
251 strerror(errnum));
252 }
253 #endif /* !defined(__minix) */
254
255 /* We explicitly ignore errors from unmapping because at this point the data
256 * is written and we don't care.
257 */
258 (void)munmap(write_buffer, file_size);
259 write_buffer = NULL;
260 file_size = 0;
261 }
262
263 /*
264 * --- LLVM line counter API ---
265 */
266
267 /* A file in this case is a translation unit. Each .o file built with line
268 * profiling enabled will emit to a different file. Only one file may be
269 * started at a time.
270 */
llvm_gcda_start_file(const char * orig_filename,const char version[4],uint32_t checksum)271 void llvm_gcda_start_file(const char *orig_filename, const char version[4],
272 uint32_t checksum) {
273 const char *mode = "r+b";
274 filename = mangle_filename(orig_filename);
275
276 /* Try just opening the file. */
277 new_file = 0;
278 fd = open(filename, O_RDWR);
279
280 if (fd == -1) {
281 /* Try opening the file, creating it if necessary. */
282 new_file = 1;
283 mode = "w+b";
284 fd = open(filename, O_RDWR | O_CREAT, 0644);
285 if (fd == -1) {
286 /* Try creating the directories first then opening the file. */
287 recursive_mkdir(filename);
288 fd = open(filename, O_RDWR | O_CREAT, 0644);
289 if (fd == -1) {
290 /* Bah! It's hopeless. */
291 int errnum = errno;
292 fprintf(stderr, "profiling: %s: cannot open: %s\n", filename,
293 strerror(errnum));
294 return;
295 }
296 }
297 }
298
299 output_file = fdopen(fd, mode);
300
301 /* Initialize the write buffer. */
302 write_buffer = NULL;
303 cur_buffer_size = 0;
304 cur_pos = 0;
305
306 if (new_file) {
307 resize_write_buffer(WRITE_BUFFER_SIZE);
308 memset(write_buffer, 0, WRITE_BUFFER_SIZE);
309 } else {
310 if (map_file() == -1) {
311 /* mmap failed, try to recover by clobbering */
312 new_file = 1;
313 write_buffer = NULL;
314 cur_buffer_size = 0;
315 resize_write_buffer(WRITE_BUFFER_SIZE);
316 memset(write_buffer, 0, WRITE_BUFFER_SIZE);
317 }
318 }
319
320 /* gcda file, version, stamp checksum. */
321 write_bytes("adcg", 4);
322 write_bytes(version, 4);
323 write_32bit_value(checksum);
324
325 #ifdef DEBUG_GCDAPROFILING
326 fprintf(stderr, "llvmgcda: [%s]\n", orig_filename);
327 #endif
328 }
329
330 /* Given an array of pointers to counters (counters), increment the n-th one,
331 * where we're also given a pointer to n (predecessor).
332 */
llvm_gcda_increment_indirect_counter(uint32_t * predecessor,uint64_t ** counters)333 void llvm_gcda_increment_indirect_counter(uint32_t *predecessor,
334 uint64_t **counters) {
335 uint64_t *counter;
336 uint32_t pred;
337
338 pred = *predecessor;
339 if (pred == 0xffffffff)
340 return;
341 counter = counters[pred];
342
343 /* Don't crash if the pred# is out of sync. This can happen due to threads,
344 or because of a TODO in GCOVProfiling.cpp buildEdgeLookupTable(). */
345 if (counter)
346 ++*counter;
347 #ifdef DEBUG_GCDAPROFILING
348 else
349 fprintf(stderr,
350 "llvmgcda: increment_indirect_counter counters=%08llx, pred=%u\n",
351 *counter, *predecessor);
352 #endif
353 }
354
llvm_gcda_emit_function(uint32_t ident,const char * function_name,uint32_t func_checksum,uint8_t use_extra_checksum,uint32_t cfg_checksum)355 void llvm_gcda_emit_function(uint32_t ident, const char *function_name,
356 uint32_t func_checksum, uint8_t use_extra_checksum,
357 uint32_t cfg_checksum) {
358 uint32_t len = 2;
359
360 if (use_extra_checksum)
361 len++;
362 #ifdef DEBUG_GCDAPROFILING
363 fprintf(stderr, "llvmgcda: function id=0x%08x name=%s\n", ident,
364 function_name ? function_name : "NULL");
365 #endif
366 if (!output_file) return;
367
368 /* function tag */
369 write_bytes("\0\0\0\1", 4);
370 if (function_name)
371 len += 1 + length_of_string(function_name);
372 write_32bit_value(len);
373 write_32bit_value(ident);
374 write_32bit_value(func_checksum);
375 if (use_extra_checksum)
376 write_32bit_value(cfg_checksum);
377 if (function_name)
378 write_string(function_name);
379 }
380
llvm_gcda_emit_arcs(uint32_t num_counters,uint64_t * counters)381 void llvm_gcda_emit_arcs(uint32_t num_counters, uint64_t *counters) {
382 uint32_t i;
383 uint64_t *old_ctrs = NULL;
384 uint32_t val = 0;
385 uint64_t save_cur_pos = cur_pos;
386
387 if (!output_file) return;
388
389 val = read_32bit_value();
390
391 if (val != (uint32_t)-1) {
392 /* There are counters present in the file. Merge them. */
393 if (val != 0x01a10000) {
394 fprintf(stderr, "profiling:invalid arc tag (0x%08x)\n", val);
395 return;
396 }
397
398 val = read_32bit_value();
399 if (val == (uint32_t)-1 || val / 2 != num_counters) {
400 fprintf(stderr, "profiling:invalid number of counters (%d)\n", val);
401 return;
402 }
403
404 old_ctrs = malloc(sizeof(uint64_t) * num_counters);
405 for (i = 0; i < num_counters; ++i)
406 old_ctrs[i] = read_64bit_value();
407 }
408
409 cur_pos = save_cur_pos;
410
411 /* Counter #1 (arcs) tag */
412 write_bytes("\0\0\xa1\1", 4);
413 write_32bit_value(num_counters * 2);
414 for (i = 0; i < num_counters; ++i) {
415 counters[i] += (old_ctrs ? old_ctrs[i] : 0);
416 write_64bit_value(counters[i]);
417 }
418
419 free(old_ctrs);
420
421 #ifdef DEBUG_GCDAPROFILING
422 fprintf(stderr, "llvmgcda: %u arcs\n", num_counters);
423 for (i = 0; i < num_counters; ++i)
424 fprintf(stderr, "llvmgcda: %llu\n", (unsigned long long)counters[i]);
425 #endif
426 }
427
llvm_gcda_summary_info()428 void llvm_gcda_summary_info() {
429 const uint32_t obj_summary_len = 9; /* Length for gcov compatibility. */
430 uint32_t i;
431 uint32_t runs = 1;
432 uint32_t val = 0;
433 uint64_t save_cur_pos = cur_pos;
434
435 if (!output_file) return;
436
437 val = read_32bit_value();
438
439 if (val != (uint32_t)-1) {
440 /* There are counters present in the file. Merge them. */
441 if (val != 0xa1000000) {
442 fprintf(stderr, "profiling:invalid object tag (0x%08x)\n", val);
443 return;
444 }
445
446 val = read_32bit_value(); /* length */
447 if (val != obj_summary_len) {
448 fprintf(stderr, "profiling:invalid object length (%d)\n", val);
449 return;
450 }
451
452 read_32bit_value(); /* checksum, unused */
453 read_32bit_value(); /* num, unused */
454 runs += read_32bit_value(); /* Add previous run count to new counter. */
455 }
456
457 cur_pos = save_cur_pos;
458
459 /* Object summary tag */
460 write_bytes("\0\0\0\xa1", 4);
461 write_32bit_value(obj_summary_len);
462 write_32bit_value(0); /* checksum, unused */
463 write_32bit_value(0); /* num, unused */
464 write_32bit_value(runs);
465 for (i = 3; i < obj_summary_len; ++i)
466 write_32bit_value(0);
467
468 /* Program summary tag */
469 write_bytes("\0\0\0\xa3", 4); /* tag indicates 1 program */
470 write_32bit_value(0); /* 0 length */
471
472 #ifdef DEBUG_GCDAPROFILING
473 fprintf(stderr, "llvmgcda: %u runs\n", runs);
474 #endif
475 }
476
llvm_gcda_end_file()477 void llvm_gcda_end_file() {
478 /* Write out EOF record. */
479 if (output_file) {
480 write_bytes("\0\0\0\0\0\0\0\0", 8);
481
482 if (new_file) {
483 fwrite(write_buffer, cur_pos, 1, output_file);
484 free(write_buffer);
485 } else {
486 unmap_file();
487 }
488
489 fclose(output_file);
490 output_file = NULL;
491 write_buffer = NULL;
492 }
493 free(filename);
494
495 #ifdef DEBUG_GCDAPROFILING
496 fprintf(stderr, "llvmgcda: -----\n");
497 #endif
498 }
499
llvm_register_writeout_function(writeout_fn fn)500 void llvm_register_writeout_function(writeout_fn fn) {
501 struct writeout_fn_node *new_node = malloc(sizeof(struct writeout_fn_node));
502 new_node->fn = fn;
503 new_node->next = NULL;
504
505 if (!writeout_fn_head) {
506 writeout_fn_head = writeout_fn_tail = new_node;
507 } else {
508 writeout_fn_tail->next = new_node;
509 writeout_fn_tail = new_node;
510 }
511 }
512
llvm_writeout_files()513 void llvm_writeout_files() {
514 struct writeout_fn_node *curr = writeout_fn_head;
515
516 while (curr) {
517 curr->fn();
518 curr = curr->next;
519 }
520 }
521
llvm_delete_writeout_function_list()522 void llvm_delete_writeout_function_list() {
523 while (writeout_fn_head) {
524 struct writeout_fn_node *node = writeout_fn_head;
525 writeout_fn_head = writeout_fn_head->next;
526 free(node);
527 }
528
529 writeout_fn_head = writeout_fn_tail = NULL;
530 }
531
llvm_register_flush_function(flush_fn fn)532 void llvm_register_flush_function(flush_fn fn) {
533 struct flush_fn_node *new_node = malloc(sizeof(struct flush_fn_node));
534 new_node->fn = fn;
535 new_node->next = NULL;
536
537 if (!flush_fn_head) {
538 flush_fn_head = flush_fn_tail = new_node;
539 } else {
540 flush_fn_tail->next = new_node;
541 flush_fn_tail = new_node;
542 }
543 }
544
__gcov_flush()545 void __gcov_flush() {
546 struct flush_fn_node *curr = flush_fn_head;
547
548 while (curr) {
549 curr->fn();
550 curr = curr->next;
551 }
552 }
553
llvm_delete_flush_function_list()554 void llvm_delete_flush_function_list() {
555 while (flush_fn_head) {
556 struct flush_fn_node *node = flush_fn_head;
557 flush_fn_head = flush_fn_head->next;
558 free(node);
559 }
560
561 flush_fn_head = flush_fn_tail = NULL;
562 }
563
llvm_gcov_init(writeout_fn wfn,flush_fn ffn)564 void llvm_gcov_init(writeout_fn wfn, flush_fn ffn) {
565 static int atexit_ran = 0;
566
567 if (wfn)
568 llvm_register_writeout_function(wfn);
569
570 if (ffn)
571 llvm_register_flush_function(ffn);
572
573 if (atexit_ran == 0) {
574 atexit_ran = 1;
575
576 /* Make sure we write out the data and delete the data structures. */
577 atexit(llvm_delete_flush_function_list);
578 atexit(llvm_delete_writeout_function_list);
579 atexit(llvm_writeout_files);
580 }
581 }
582