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 #if !defined(__Fuchsia__)
24
25 #include <errno.h>
26 #include <fcntl.h>
27 #include <stdio.h>
28 #include <stdlib.h>
29 #include <string.h>
30
31 #if defined(_WIN32)
32 #define WIN32_LEAN_AND_MEAN
33 #include <windows.h>
34 #include "WindowsMMap.h"
35 #else
36 #include <sys/mman.h>
37 #include <sys/file.h>
38 #endif
39
40 #if defined(__FreeBSD__) && defined(__i386__)
41 #define I386_FREEBSD 1
42 #else
43 #define I386_FREEBSD 0
44 #endif
45
46 #if !defined(_MSC_VER) && !I386_FREEBSD
47 #include <stdint.h>
48 #endif
49
50 #if defined(_MSC_VER)
51 typedef unsigned char uint8_t;
52 typedef unsigned int uint32_t;
53 typedef unsigned long long uint64_t;
54 #elif I386_FREEBSD
55 /* System headers define 'size_t' incorrectly on x64 FreeBSD (prior to
56 * FreeBSD 10, r232261) when compiled in 32-bit mode.
57 */
58 typedef unsigned char uint8_t;
59 typedef unsigned int uint32_t;
60 typedef unsigned long long uint64_t;
61 #endif
62
63 #include "InstrProfiling.h"
64 #include "InstrProfilingUtil.h"
65
66 /* #define DEBUG_GCDAPROFILING */
67
68 /*
69 * --- GCOV file format I/O primitives ---
70 */
71
72 /*
73 * The current file name we're outputting. Used primarily for error logging.
74 */
75 static char *filename = NULL;
76
77 /*
78 * The current file we're outputting.
79 */
80 static FILE *output_file = NULL;
81
82 /*
83 * Buffer that we write things into.
84 */
85 #define WRITE_BUFFER_SIZE (128 * 1024)
86 static unsigned char *write_buffer = NULL;
87 static uint64_t cur_buffer_size = 0;
88 static uint64_t cur_pos = 0;
89 static uint64_t file_size = 0;
90 static int new_file = 0;
91 #if defined(_WIN32)
92 static HANDLE mmap_handle = NULL;
93 #endif
94 static int fd = -1;
95
96 typedef void (*fn_ptr)();
97
98 typedef void* dynamic_object_id;
99 // The address of this variable identifies a given dynamic object.
100 static dynamic_object_id current_id;
101 #define CURRENT_ID (¤t_id)
102
103 struct fn_node {
104 dynamic_object_id id;
105 fn_ptr fn;
106 struct fn_node* next;
107 };
108
109 struct fn_list {
110 struct fn_node *head, *tail;
111 };
112
113 /*
114 * A list of functions to write out the data, shared between all dynamic objects.
115 */
116 struct fn_list writeout_fn_list;
117
118 /*
119 * A list of flush functions that our __gcov_flush() function should call, shared between all dynamic objects.
120 */
121 struct fn_list flush_fn_list;
122
fn_list_insert(struct fn_list * list,fn_ptr fn)123 static void fn_list_insert(struct fn_list* list, fn_ptr fn) {
124 struct fn_node* new_node = malloc(sizeof(struct fn_node));
125 new_node->fn = fn;
126 new_node->next = NULL;
127 new_node->id = CURRENT_ID;
128
129 if (!list->head) {
130 list->head = list->tail = new_node;
131 } else {
132 list->tail->next = new_node;
133 list->tail = new_node;
134 }
135 }
136
fn_list_remove(struct fn_list * list)137 static void fn_list_remove(struct fn_list* list) {
138 struct fn_node* curr = list->head;
139 struct fn_node* prev = NULL;
140 struct fn_node* next = NULL;
141
142 while (curr) {
143 next = curr->next;
144
145 if (curr->id == CURRENT_ID) {
146 if (curr == list->head) {
147 list->head = next;
148 }
149
150 if (curr == list->tail) {
151 list->tail = prev;
152 }
153
154 if (prev) {
155 prev->next = next;
156 }
157
158 free(curr);
159 } else {
160 prev = curr;
161 }
162
163 curr = next;
164 }
165 }
166
resize_write_buffer(uint64_t size)167 static void resize_write_buffer(uint64_t size) {
168 if (!new_file) return;
169 size += cur_pos;
170 if (size <= cur_buffer_size) return;
171 size = (size - 1) / WRITE_BUFFER_SIZE + 1;
172 size *= WRITE_BUFFER_SIZE;
173 write_buffer = realloc(write_buffer, size);
174 cur_buffer_size = size;
175 }
176
write_bytes(const char * s,size_t len)177 static void write_bytes(const char *s, size_t len) {
178 resize_write_buffer(len);
179 memcpy(&write_buffer[cur_pos], s, len);
180 cur_pos += len;
181 }
182
write_32bit_value(uint32_t i)183 static void write_32bit_value(uint32_t i) {
184 write_bytes((char*)&i, 4);
185 }
186
write_64bit_value(uint64_t i)187 static void write_64bit_value(uint64_t i) {
188 // GCOV uses a lo-/hi-word format even on big-endian systems.
189 // See also GCOVBuffer::readInt64 in LLVM.
190 uint32_t lo = (uint32_t) i;
191 uint32_t hi = (uint32_t) (i >> 32);
192 write_32bit_value(lo);
193 write_32bit_value(hi);
194 }
195
length_of_string(const char * s)196 static uint32_t length_of_string(const char *s) {
197 return (strlen(s) / 4) + 1;
198 }
199
write_string(const char * s)200 static void write_string(const char *s) {
201 uint32_t len = length_of_string(s);
202 write_32bit_value(len);
203 write_bytes(s, strlen(s));
204 write_bytes("\0\0\0\0", 4 - (strlen(s) % 4));
205 }
206
read_32bit_value()207 static uint32_t read_32bit_value() {
208 uint32_t val;
209
210 if (new_file)
211 return (uint32_t)-1;
212
213 val = *(uint32_t*)&write_buffer[cur_pos];
214 cur_pos += 4;
215 return val;
216 }
217
read_le_32bit_value()218 static uint32_t read_le_32bit_value() {
219 uint32_t val = 0;
220 int i;
221
222 if (new_file)
223 return (uint32_t)-1;
224
225 for (i = 0; i < 4; i++)
226 val |= write_buffer[cur_pos++] << (8*i);
227 return val;
228 }
229
read_64bit_value()230 static uint64_t read_64bit_value() {
231 // GCOV uses a lo-/hi-word format even on big-endian systems.
232 // See also GCOVBuffer::readInt64 in LLVM.
233 uint32_t lo = read_32bit_value();
234 uint32_t hi = read_32bit_value();
235 return ((uint64_t)hi << 32) | ((uint64_t)lo);
236 }
237
mangle_filename(const char * orig_filename)238 static char *mangle_filename(const char *orig_filename) {
239 char *new_filename;
240 size_t prefix_len;
241 int prefix_strip;
242 const char *prefix = lprofGetPathPrefix(&prefix_strip, &prefix_len);
243
244 if (prefix == NULL)
245 return strdup(orig_filename);
246
247 new_filename = malloc(prefix_len + 1 + strlen(orig_filename) + 1);
248 lprofApplyPathPrefix(new_filename, orig_filename, prefix, prefix_len,
249 prefix_strip);
250
251 return new_filename;
252 }
253
map_file()254 static int map_file() {
255 fseek(output_file, 0L, SEEK_END);
256 file_size = ftell(output_file);
257
258 /* A size of 0 is invalid to `mmap'. Return a fail here, but don't issue an
259 * error message because it should "just work" for the user. */
260 if (file_size == 0)
261 return -1;
262
263 #if defined(_WIN32)
264 HANDLE mmap_fd;
265 if (fd == -1)
266 mmap_fd = INVALID_HANDLE_VALUE;
267 else
268 mmap_fd = (HANDLE)_get_osfhandle(fd);
269
270 mmap_handle = CreateFileMapping(mmap_fd, NULL, PAGE_READWRITE, DWORD_HI(file_size), DWORD_LO(file_size), NULL);
271 if (mmap_handle == NULL) {
272 fprintf(stderr, "profiling: %s: cannot create file mapping: %d\n", filename,
273 GetLastError());
274 return -1;
275 }
276
277 write_buffer = MapViewOfFile(mmap_handle, FILE_MAP_WRITE, 0, 0, file_size);
278 if (write_buffer == NULL) {
279 fprintf(stderr, "profiling: %s: cannot map: %d\n", filename,
280 GetLastError());
281 CloseHandle(mmap_handle);
282 return -1;
283 }
284 #else
285 write_buffer = mmap(0, file_size, PROT_READ | PROT_WRITE,
286 MAP_FILE | MAP_SHARED, fd, 0);
287 if (write_buffer == (void *)-1) {
288 int errnum = errno;
289 fprintf(stderr, "profiling: %s: cannot map: %s\n", filename,
290 strerror(errnum));
291 return -1;
292 }
293 #endif
294
295 return 0;
296 }
297
unmap_file()298 static void unmap_file() {
299 #if defined(_WIN32)
300 if (!FlushViewOfFile(write_buffer, file_size)) {
301 fprintf(stderr, "profiling: %s: cannot flush mapped view: %d\n", filename,
302 GetLastError());
303 }
304
305 if (!UnmapViewOfFile(write_buffer)) {
306 fprintf(stderr, "profiling: %s: cannot unmap mapped view: %d\n", filename,
307 GetLastError());
308 }
309
310 if (!CloseHandle(mmap_handle)) {
311 fprintf(stderr, "profiling: %s: cannot close file mapping handle: %d\n", filename,
312 GetLastError());
313 }
314
315 mmap_handle = NULL;
316 #else
317 if (msync(write_buffer, file_size, MS_SYNC) == -1) {
318 int errnum = errno;
319 fprintf(stderr, "profiling: %s: cannot msync: %s\n", filename,
320 strerror(errnum));
321 }
322
323 /* We explicitly ignore errors from unmapping because at this point the data
324 * is written and we don't care.
325 */
326 (void)munmap(write_buffer, file_size);
327 #endif
328
329 write_buffer = NULL;
330 file_size = 0;
331 }
332
333 /*
334 * --- LLVM line counter API ---
335 */
336
337 /* A file in this case is a translation unit. Each .o file built with line
338 * profiling enabled will emit to a different file. Only one file may be
339 * started at a time.
340 */
341 COMPILER_RT_VISIBILITY
llvm_gcda_start_file(const char * orig_filename,const char version[4],uint32_t checksum)342 void llvm_gcda_start_file(const char *orig_filename, const char version[4],
343 uint32_t checksum) {
344 const char *mode = "r+b";
345 filename = mangle_filename(orig_filename);
346
347 /* Try just opening the file. */
348 new_file = 0;
349 fd = open(filename, O_RDWR | O_BINARY);
350
351 if (fd == -1) {
352 /* Try opening the file, creating it if necessary. */
353 new_file = 1;
354 mode = "w+b";
355 fd = open(filename, O_RDWR | O_CREAT | O_BINARY, 0644);
356 if (fd == -1) {
357 /* Try creating the directories first then opening the file. */
358 __llvm_profile_recursive_mkdir(filename);
359 fd = open(filename, O_RDWR | O_CREAT | O_BINARY, 0644);
360 if (fd == -1) {
361 /* Bah! It's hopeless. */
362 int errnum = errno;
363 fprintf(stderr, "profiling: %s: cannot open: %s\n", filename,
364 strerror(errnum));
365 return;
366 }
367 }
368 }
369
370 /* Try to flock the file to serialize concurrent processes writing out to the
371 * same GCDA. This can fail if the filesystem doesn't support it, but in that
372 * case we'll just carry on with the old racy behaviour and hope for the best.
373 */
374 lprofLockFd(fd);
375 output_file = fdopen(fd, mode);
376
377 /* Initialize the write buffer. */
378 write_buffer = NULL;
379 cur_buffer_size = 0;
380 cur_pos = 0;
381
382 if (new_file) {
383 resize_write_buffer(WRITE_BUFFER_SIZE);
384 memset(write_buffer, 0, WRITE_BUFFER_SIZE);
385 } else {
386 if (map_file() == -1) {
387 /* mmap failed, try to recover by clobbering */
388 new_file = 1;
389 write_buffer = NULL;
390 cur_buffer_size = 0;
391 resize_write_buffer(WRITE_BUFFER_SIZE);
392 memset(write_buffer, 0, WRITE_BUFFER_SIZE);
393 }
394 }
395
396 /* gcda file, version, stamp checksum. */
397 write_bytes("adcg", 4);
398 write_bytes(version, 4);
399 write_32bit_value(checksum);
400
401 #ifdef DEBUG_GCDAPROFILING
402 fprintf(stderr, "llvmgcda: [%s]\n", orig_filename);
403 #endif
404 }
405
406 /* Given an array of pointers to counters (counters), increment the n-th one,
407 * where we're also given a pointer to n (predecessor).
408 */
409 COMPILER_RT_VISIBILITY
llvm_gcda_increment_indirect_counter(uint32_t * predecessor,uint64_t ** counters)410 void llvm_gcda_increment_indirect_counter(uint32_t *predecessor,
411 uint64_t **counters) {
412 uint64_t *counter;
413 uint32_t pred;
414
415 pred = *predecessor;
416 if (pred == 0xffffffff)
417 return;
418 counter = counters[pred];
419
420 /* Don't crash if the pred# is out of sync. This can happen due to threads,
421 or because of a TODO in GCOVProfiling.cpp buildEdgeLookupTable(). */
422 if (counter)
423 ++*counter;
424 #ifdef DEBUG_GCDAPROFILING
425 else
426 fprintf(stderr,
427 "llvmgcda: increment_indirect_counter counters=%08llx, pred=%u\n",
428 *counter, *predecessor);
429 #endif
430 }
431
432 COMPILER_RT_VISIBILITY
llvm_gcda_emit_function(uint32_t ident,const char * function_name,uint32_t func_checksum,uint8_t use_extra_checksum,uint32_t cfg_checksum)433 void llvm_gcda_emit_function(uint32_t ident, const char *function_name,
434 uint32_t func_checksum, uint8_t use_extra_checksum,
435 uint32_t cfg_checksum) {
436 uint32_t len = 2;
437
438 if (use_extra_checksum)
439 len++;
440 #ifdef DEBUG_GCDAPROFILING
441 fprintf(stderr, "llvmgcda: function id=0x%08x name=%s\n", ident,
442 function_name ? function_name : "NULL");
443 #endif
444 if (!output_file) return;
445
446 /* function tag */
447 write_bytes("\0\0\0\1", 4);
448 if (function_name)
449 len += 1 + length_of_string(function_name);
450 write_32bit_value(len);
451 write_32bit_value(ident);
452 write_32bit_value(func_checksum);
453 if (use_extra_checksum)
454 write_32bit_value(cfg_checksum);
455 if (function_name)
456 write_string(function_name);
457 }
458
459 COMPILER_RT_VISIBILITY
llvm_gcda_emit_arcs(uint32_t num_counters,uint64_t * counters)460 void llvm_gcda_emit_arcs(uint32_t num_counters, uint64_t *counters) {
461 uint32_t i;
462 uint64_t *old_ctrs = NULL;
463 uint32_t val = 0;
464 uint64_t save_cur_pos = cur_pos;
465
466 if (!output_file) return;
467
468 val = read_le_32bit_value();
469
470 if (val != (uint32_t)-1) {
471 /* There are counters present in the file. Merge them. */
472 if (val != 0x01a10000) {
473 fprintf(stderr, "profiling: %s: cannot merge previous GCDA file: "
474 "corrupt arc tag (0x%08x)\n",
475 filename, val);
476 return;
477 }
478
479 val = read_32bit_value();
480 if (val == (uint32_t)-1 || val / 2 != num_counters) {
481 fprintf(stderr, "profiling: %s: cannot merge previous GCDA file: "
482 "mismatched number of counters (%d)\n",
483 filename, val);
484 return;
485 }
486
487 old_ctrs = malloc(sizeof(uint64_t) * num_counters);
488 for (i = 0; i < num_counters; ++i)
489 old_ctrs[i] = read_64bit_value();
490 }
491
492 cur_pos = save_cur_pos;
493
494 /* Counter #1 (arcs) tag */
495 write_bytes("\0\0\xa1\1", 4);
496 write_32bit_value(num_counters * 2);
497 for (i = 0; i < num_counters; ++i) {
498 counters[i] += (old_ctrs ? old_ctrs[i] : 0);
499 write_64bit_value(counters[i]);
500 }
501
502 free(old_ctrs);
503
504 #ifdef DEBUG_GCDAPROFILING
505 fprintf(stderr, "llvmgcda: %u arcs\n", num_counters);
506 for (i = 0; i < num_counters; ++i)
507 fprintf(stderr, "llvmgcda: %llu\n", (unsigned long long)counters[i]);
508 #endif
509 }
510
511 COMPILER_RT_VISIBILITY
llvm_gcda_summary_info()512 void llvm_gcda_summary_info() {
513 const uint32_t obj_summary_len = 9; /* Length for gcov compatibility. */
514 uint32_t i;
515 uint32_t runs = 1;
516 static uint32_t run_counted = 0; // We only want to increase the run count once.
517 uint32_t val = 0;
518 uint64_t save_cur_pos = cur_pos;
519
520 if (!output_file) return;
521
522 val = read_le_32bit_value();
523
524 if (val != (uint32_t)-1) {
525 /* There are counters present in the file. Merge them. */
526 if (val != 0xa1000000) {
527 fprintf(stderr, "profiling: %s: cannot merge previous run count: "
528 "corrupt object tag (0x%08x)\n",
529 filename, val);
530 return;
531 }
532
533 val = read_32bit_value(); /* length */
534 if (val != obj_summary_len) {
535 fprintf(stderr, "profiling: %s: cannot merge previous run count: "
536 "mismatched object length (%d)\n",
537 filename, val);
538 return;
539 }
540
541 read_32bit_value(); /* checksum, unused */
542 read_32bit_value(); /* num, unused */
543 uint32_t prev_runs = read_32bit_value();
544 /* Add previous run count to new counter, if not already counted before. */
545 runs = run_counted ? prev_runs : prev_runs + 1;
546 }
547
548 cur_pos = save_cur_pos;
549
550 /* Object summary tag */
551 write_bytes("\0\0\0\xa1", 4);
552 write_32bit_value(obj_summary_len);
553 write_32bit_value(0); /* checksum, unused */
554 write_32bit_value(0); /* num, unused */
555 write_32bit_value(runs);
556 for (i = 3; i < obj_summary_len; ++i)
557 write_32bit_value(0);
558
559 /* Program summary tag */
560 write_bytes("\0\0\0\xa3", 4); /* tag indicates 1 program */
561 write_32bit_value(0); /* 0 length */
562
563 run_counted = 1;
564
565 #ifdef DEBUG_GCDAPROFILING
566 fprintf(stderr, "llvmgcda: %u runs\n", runs);
567 #endif
568 }
569
570 COMPILER_RT_VISIBILITY
llvm_gcda_end_file()571 void llvm_gcda_end_file() {
572 /* Write out EOF record. */
573 if (output_file) {
574 write_bytes("\0\0\0\0\0\0\0\0", 8);
575
576 if (new_file) {
577 fwrite(write_buffer, cur_pos, 1, output_file);
578 free(write_buffer);
579 } else {
580 unmap_file();
581 }
582
583 fflush(output_file);
584 lprofUnlockFd(fd);
585 fclose(output_file);
586 output_file = NULL;
587 write_buffer = NULL;
588 }
589 free(filename);
590
591 #ifdef DEBUG_GCDAPROFILING
592 fprintf(stderr, "llvmgcda: -----\n");
593 #endif
594 }
595
596 COMPILER_RT_VISIBILITY
llvm_register_writeout_function(fn_ptr fn)597 void llvm_register_writeout_function(fn_ptr fn) {
598 fn_list_insert(&writeout_fn_list, fn);
599 }
600
601 COMPILER_RT_VISIBILITY
llvm_writeout_files(void)602 void llvm_writeout_files(void) {
603 struct fn_node *curr = writeout_fn_list.head;
604
605 while (curr) {
606 if (curr->id == CURRENT_ID) {
607 curr->fn();
608 }
609 curr = curr->next;
610 }
611 }
612
613 COMPILER_RT_VISIBILITY
llvm_delete_writeout_function_list(void)614 void llvm_delete_writeout_function_list(void) {
615 fn_list_remove(&writeout_fn_list);
616 }
617
618 COMPILER_RT_VISIBILITY
llvm_register_flush_function(fn_ptr fn)619 void llvm_register_flush_function(fn_ptr fn) {
620 fn_list_insert(&flush_fn_list, fn);
621 }
622
__gcov_flush()623 void __gcov_flush() {
624 struct fn_node* curr = flush_fn_list.head;
625
626 while (curr) {
627 curr->fn();
628 curr = curr->next;
629 }
630 }
631
632 COMPILER_RT_VISIBILITY
llvm_delete_flush_function_list(void)633 void llvm_delete_flush_function_list(void) {
634 fn_list_remove(&flush_fn_list);
635 }
636
637 COMPILER_RT_VISIBILITY
llvm_gcov_init(fn_ptr wfn,fn_ptr ffn)638 void llvm_gcov_init(fn_ptr wfn, fn_ptr ffn) {
639 static int atexit_ran = 0;
640
641 if (wfn)
642 llvm_register_writeout_function(wfn);
643
644 if (ffn)
645 llvm_register_flush_function(ffn);
646
647 if (atexit_ran == 0) {
648 atexit_ran = 1;
649
650 /* Make sure we write out the data and delete the data structures. */
651 atexit(llvm_delete_flush_function_list);
652 atexit(llvm_delete_writeout_function_list);
653 atexit(llvm_writeout_files);
654 }
655 }
656
657 #endif
658