1 //===-- asan_rtl.cc ---------------------------------------------*- C++ -*-===//
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 is a part of AddressSanitizer, an address sanity checker.
11 //
12 // Main file of the ASan run-time library.
13 //===----------------------------------------------------------------------===//
14 #include "asan_allocator.h"
15 #include "asan_interceptors.h"
16 #include "asan_interface.h"
17 #include "asan_internal.h"
18 #include "asan_lock.h"
19 #include "asan_mapping.h"
20 #include "asan_stack.h"
21 #include "asan_stats.h"
22 #include "asan_thread.h"
23 #include "asan_thread_registry.h"
24
25 namespace __asan {
26
27 // -------------------------- Flags ------------------------- {{{1
28 static const size_t kMallocContextSize = 30;
29 static int FLAG_atexit;
30
31 size_t FLAG_redzone; // power of two, >= 32
32 size_t FLAG_quarantine_size;
33 int FLAG_demangle;
34 bool FLAG_symbolize;
35 int FLAG_v;
36 int FLAG_debug;
37 bool FLAG_poison_shadow;
38 int FLAG_report_globals;
39 size_t FLAG_malloc_context_size = kMallocContextSize;
40 uintptr_t FLAG_large_malloc;
41 bool FLAG_handle_segv;
42 bool FLAG_use_sigaltstack;
43 bool FLAG_replace_str;
44 bool FLAG_replace_intrin;
45 bool FLAG_replace_cfallocator; // Used on Mac only.
46 size_t FLAG_max_malloc_fill_size = 0;
47 bool FLAG_use_fake_stack;
48 bool FLAG_abort_on_error;
49 int FLAG_exitcode = ASAN_DEFAULT_FAILURE_EXITCODE;
50 bool FLAG_allow_user_poisoning;
51 int FLAG_sleep_before_dying;
52 bool FLAG_unmap_shadow_on_exit;
53 bool FLAG_disable_core;
54
55 // -------------------------- Globals --------------------- {{{1
56 int asan_inited;
57 bool asan_init_is_running;
58 static void (*death_callback)(void);
59 static void (*error_report_callback)(const char*);
60 char *error_message_buffer = NULL;
61 size_t error_message_buffer_pos = 0;
62 size_t error_message_buffer_size = 0;
63
64 // -------------------------- Misc ---------------- {{{1
ShowStatsAndAbort()65 void ShowStatsAndAbort() {
66 __asan_print_accumulated_stats();
67 AsanDie();
68 }
69
PrintBytes(const char * before,uintptr_t * a)70 static void PrintBytes(const char *before, uintptr_t *a) {
71 uint8_t *bytes = (uint8_t*)a;
72 size_t byte_num = (__WORDSIZE) / 8;
73 Printf("%s%p:", before, (void*)a);
74 for (size_t i = 0; i < byte_num; i++) {
75 Printf(" %x%x", bytes[i] >> 4, bytes[i] & 15);
76 }
77 Printf("\n");
78 }
79
ReadFileToBuffer(const char * file_name,char ** buff,size_t * buff_size,size_t max_len)80 size_t ReadFileToBuffer(const char *file_name, char **buff,
81 size_t *buff_size, size_t max_len) {
82 const size_t kMinFileLen = kPageSize;
83 size_t read_len = 0;
84 *buff = 0;
85 *buff_size = 0;
86 // The files we usually open are not seekable, so try different buffer sizes.
87 for (size_t size = kMinFileLen; size <= max_len; size *= 2) {
88 int fd = AsanOpenReadonly(file_name);
89 if (fd < 0) return -1;
90 AsanUnmapOrDie(*buff, *buff_size);
91 *buff = (char*)AsanMmapSomewhereOrDie(size, __FUNCTION__);
92 *buff_size = size;
93 // Read up to one page at a time.
94 read_len = 0;
95 bool reached_eof = false;
96 while (read_len + kPageSize <= size) {
97 size_t just_read = AsanRead(fd, *buff + read_len, kPageSize);
98 if (just_read == 0) {
99 reached_eof = true;
100 break;
101 }
102 read_len += just_read;
103 }
104 AsanClose(fd);
105 if (reached_eof) // We've read the whole file.
106 break;
107 }
108 return read_len;
109 }
110
AsanDie()111 void AsanDie() {
112 static int num_calls = 0;
113 if (AtomicInc(&num_calls) > 1) {
114 // Don't die twice - run a busy loop.
115 while (1) { }
116 }
117 if (FLAG_sleep_before_dying) {
118 Report("Sleeping for %d second(s)\n", FLAG_sleep_before_dying);
119 SleepForSeconds(FLAG_sleep_before_dying);
120 }
121 if (FLAG_unmap_shadow_on_exit)
122 AsanUnmapOrDie((void*)kLowShadowBeg, kHighShadowEnd - kLowShadowBeg);
123 if (death_callback)
124 death_callback();
125 if (FLAG_abort_on_error)
126 Abort();
127 Exit(FLAG_exitcode);
128 }
129
130 // ---------------------- mmap -------------------- {{{1
OutOfMemoryMessageAndDie(const char * mem_type,size_t size)131 void OutOfMemoryMessageAndDie(const char *mem_type, size_t size) {
132 Report("ERROR: AddressSanitizer failed to allocate "
133 "0x%zx (%zd) bytes of %s\n",
134 size, size, mem_type);
135 PRINT_CURRENT_STACK();
136 ShowStatsAndAbort();
137 }
138
139 // Reserve memory range [beg, end].
ReserveShadowMemoryRange(uintptr_t beg,uintptr_t end)140 static void ReserveShadowMemoryRange(uintptr_t beg, uintptr_t end) {
141 CHECK((beg % kPageSize) == 0);
142 CHECK(((end + 1) % kPageSize) == 0);
143 size_t size = end - beg + 1;
144 void *res = AsanMmapFixedNoReserve(beg, size);
145 CHECK(res == (void*)beg && "ReserveShadowMemoryRange failed");
146 }
147
148 // ---------------------- LowLevelAllocator ------------- {{{1
Allocate(size_t size)149 void *LowLevelAllocator::Allocate(size_t size) {
150 CHECK((size & (size - 1)) == 0 && "size must be a power of two");
151 if (allocated_end_ - allocated_current_ < size) {
152 size_t size_to_allocate = Max(size, kPageSize);
153 allocated_current_ =
154 (char*)AsanMmapSomewhereOrDie(size_to_allocate, __FUNCTION__);
155 allocated_end_ = allocated_current_ + size_to_allocate;
156 PoisonShadow((uintptr_t)allocated_current_, size_to_allocate,
157 kAsanInternalHeapMagic);
158 }
159 CHECK(allocated_end_ - allocated_current_ >= size);
160 void *res = allocated_current_;
161 allocated_current_ += size;
162 return res;
163 }
164
165 // ---------------------- DescribeAddress -------------------- {{{1
DescribeStackAddress(uintptr_t addr,uintptr_t access_size)166 static bool DescribeStackAddress(uintptr_t addr, uintptr_t access_size) {
167 AsanThread *t = asanThreadRegistry().FindThreadByStackAddress(addr);
168 if (!t) return false;
169 const intptr_t kBufSize = 4095;
170 char buf[kBufSize];
171 uintptr_t offset = 0;
172 const char *frame_descr = t->GetFrameNameByAddr(addr, &offset);
173 // This string is created by the compiler and has the following form:
174 // "FunctioName n alloc_1 alloc_2 ... alloc_n"
175 // where alloc_i looks like "offset size len ObjectName ".
176 CHECK(frame_descr);
177 // Report the function name and the offset.
178 const char *name_end = internal_strchr(frame_descr, ' ');
179 CHECK(name_end);
180 buf[0] = 0;
181 internal_strncat(buf, frame_descr,
182 Min(kBufSize,
183 static_cast<intptr_t>(name_end - frame_descr)));
184 Printf("Address %p is located at offset %zu "
185 "in frame <%s> of T%d's stack:\n",
186 addr, offset, buf, t->tid());
187 // Report the number of stack objects.
188 char *p;
189 size_t n_objects = internal_simple_strtoll(name_end, &p, 10);
190 CHECK(n_objects > 0);
191 Printf(" This frame has %zu object(s):\n", n_objects);
192 // Report all objects in this frame.
193 for (size_t i = 0; i < n_objects; i++) {
194 size_t beg, size;
195 intptr_t len;
196 beg = internal_simple_strtoll(p, &p, 10);
197 size = internal_simple_strtoll(p, &p, 10);
198 len = internal_simple_strtoll(p, &p, 10);
199 if (beg <= 0 || size <= 0 || len < 0 || *p != ' ') {
200 Printf("AddressSanitizer can't parse the stack frame descriptor: |%s|\n",
201 frame_descr);
202 break;
203 }
204 p++;
205 buf[0] = 0;
206 internal_strncat(buf, p, Min(kBufSize, len));
207 p += len;
208 Printf(" [%zu, %zu) '%s'\n", beg, beg + size, buf);
209 }
210 Printf("HINT: this may be a false positive if your program uses "
211 "some custom stack unwind mechanism\n"
212 " (longjmp and C++ exceptions *are* supported)\n");
213 t->summary()->Announce();
214 return true;
215 }
216
DescribeAddress(uintptr_t addr,uintptr_t access_size)217 static NOINLINE void DescribeAddress(uintptr_t addr, uintptr_t access_size) {
218 // Check if this is a global.
219 if (DescribeAddrIfGlobal(addr))
220 return;
221
222 if (DescribeStackAddress(addr, access_size))
223 return;
224
225 // finally, check if this is a heap.
226 DescribeHeapAddress(addr, access_size);
227 }
228
229 // -------------------------- Run-time entry ------------------- {{{1
230 // exported functions
231 #define ASAN_REPORT_ERROR(type, is_write, size) \
232 extern "C" NOINLINE ASAN_INTERFACE_ATTRIBUTE \
233 void __asan_report_ ## type ## size(uintptr_t addr); \
234 void __asan_report_ ## type ## size(uintptr_t addr) { \
235 GET_CALLER_PC_BP_SP; \
236 __asan_report_error(pc, bp, sp, addr, is_write, size); \
237 }
238
239 ASAN_REPORT_ERROR(load, false, 1)
240 ASAN_REPORT_ERROR(load, false, 2)
241 ASAN_REPORT_ERROR(load, false, 4)
242 ASAN_REPORT_ERROR(load, false, 8)
243 ASAN_REPORT_ERROR(load, false, 16)
244 ASAN_REPORT_ERROR(store, true, 1)
245 ASAN_REPORT_ERROR(store, true, 2)
246 ASAN_REPORT_ERROR(store, true, 4)
247 ASAN_REPORT_ERROR(store, true, 8)
248 ASAN_REPORT_ERROR(store, true, 16)
249
250 // Force the linker to keep the symbols for various ASan interface functions.
251 // We want to keep those in the executable in order to let the instrumented
252 // dynamic libraries access the symbol even if it is not used by the executable
253 // itself. This should help if the build system is removing dead code at link
254 // time.
force_interface_symbols()255 static NOINLINE void force_interface_symbols() {
256 volatile int fake_condition = 0; // prevent dead condition elimination.
257 if (fake_condition) {
258 __asan_report_load1(0);
259 __asan_report_load2(0);
260 __asan_report_load4(0);
261 __asan_report_load8(0);
262 __asan_report_load16(0);
263 __asan_report_store1(0);
264 __asan_report_store2(0);
265 __asan_report_store4(0);
266 __asan_report_store8(0);
267 __asan_report_store16(0);
268 __asan_register_global(0, 0, NULL);
269 __asan_register_globals(NULL, 0);
270 __asan_unregister_globals(NULL, 0);
271 __asan_set_death_callback(NULL);
272 __asan_set_error_report_callback(NULL);
273 __asan_handle_no_return();
274 }
275 }
276
277 // -------------------------- Init ------------------- {{{1
IntFlagValue(const char * flags,const char * flag,int64_t default_val)278 static int64_t IntFlagValue(const char *flags, const char *flag,
279 int64_t default_val) {
280 if (!flags) return default_val;
281 const char *str = internal_strstr(flags, flag);
282 if (!str) return default_val;
283 return internal_atoll(str + internal_strlen(flag));
284 }
285
asan_atexit()286 static void asan_atexit() {
287 Printf("AddressSanitizer exit stats:\n");
288 __asan_print_accumulated_stats();
289 }
290
CheckFailed(const char * cond,const char * file,int line)291 void CheckFailed(const char *cond, const char *file, int line) {
292 Report("CHECK failed: %s at %s:%d\n", cond, file, line);
293 PRINT_CURRENT_STACK();
294 ShowStatsAndAbort();
295 }
296
297 } // namespace __asan
298
299 // ---------------------- Interface ---------------- {{{1
300 using namespace __asan; // NOLINT
301
__asan_set_error_exit_code(int exit_code)302 int __asan_set_error_exit_code(int exit_code) {
303 int old = FLAG_exitcode;
304 FLAG_exitcode = exit_code;
305 return old;
306 }
307
__asan_handle_no_return()308 void NOINLINE __asan_handle_no_return() {
309 int local_stack;
310 AsanThread *curr_thread = asanThreadRegistry().GetCurrent();
311 CHECK(curr_thread);
312 uintptr_t top = curr_thread->stack_top();
313 uintptr_t bottom = ((uintptr_t)&local_stack - kPageSize) & ~(kPageSize-1);
314 PoisonShadow(bottom, top - bottom, 0);
315 }
316
__asan_set_death_callback(void (* callback)(void))317 void NOINLINE __asan_set_death_callback(void (*callback)(void)) {
318 death_callback = callback;
319 }
320
__asan_set_error_report_callback(void (* callback)(const char *))321 void NOINLINE __asan_set_error_report_callback(void (*callback)(const char*)) {
322 error_report_callback = callback;
323 if (callback) {
324 error_message_buffer_size = 1 << 14;
325 error_message_buffer =
326 (char*)AsanMmapSomewhereOrDie(error_message_buffer_size, __FUNCTION__);
327 error_message_buffer_pos = 0;
328 }
329 }
330
__asan_report_error(uintptr_t pc,uintptr_t bp,uintptr_t sp,uintptr_t addr,bool is_write,size_t access_size)331 void __asan_report_error(uintptr_t pc, uintptr_t bp, uintptr_t sp,
332 uintptr_t addr, bool is_write, size_t access_size) {
333 // Do not print more than one report, otherwise they will mix up.
334 static int num_calls = 0;
335 if (AtomicInc(&num_calls) > 1) return;
336
337 Printf("=================================================================\n");
338 const char *bug_descr = "unknown-crash";
339 if (AddrIsInMem(addr)) {
340 uint8_t *shadow_addr = (uint8_t*)MemToShadow(addr);
341 // If we are accessing 16 bytes, look at the second shadow byte.
342 if (*shadow_addr == 0 && access_size > SHADOW_GRANULARITY)
343 shadow_addr++;
344 // If we are in the partial right redzone, look at the next shadow byte.
345 if (*shadow_addr > 0 && *shadow_addr < 128)
346 shadow_addr++;
347 switch (*shadow_addr) {
348 case kAsanHeapLeftRedzoneMagic:
349 case kAsanHeapRightRedzoneMagic:
350 bug_descr = "heap-buffer-overflow";
351 break;
352 case kAsanHeapFreeMagic:
353 bug_descr = "heap-use-after-free";
354 break;
355 case kAsanStackLeftRedzoneMagic:
356 bug_descr = "stack-buffer-underflow";
357 break;
358 case kAsanStackMidRedzoneMagic:
359 case kAsanStackRightRedzoneMagic:
360 case kAsanStackPartialRedzoneMagic:
361 bug_descr = "stack-buffer-overflow";
362 break;
363 case kAsanStackAfterReturnMagic:
364 bug_descr = "stack-use-after-return";
365 break;
366 case kAsanUserPoisonedMemoryMagic:
367 bug_descr = "use-after-poison";
368 break;
369 case kAsanGlobalRedzoneMagic:
370 bug_descr = "global-buffer-overflow";
371 break;
372 }
373 }
374
375 AsanThread *curr_thread = asanThreadRegistry().GetCurrent();
376 int curr_tid = asanThreadRegistry().GetCurrentTidOrMinusOne();
377
378 if (curr_thread) {
379 // We started reporting an error message. Stop using the fake stack
380 // in case we will call an instrumented function from a symbolizer.
381 curr_thread->fake_stack().StopUsingFakeStack();
382 }
383
384 Report("ERROR: AddressSanitizer %s on address "
385 "%p at pc 0x%zx bp 0x%zx sp 0x%zx\n",
386 bug_descr, addr, pc, bp, sp);
387
388 Printf("%s of size %zu at %p thread T%d\n",
389 access_size ? (is_write ? "WRITE" : "READ") : "ACCESS",
390 access_size, addr, curr_tid);
391
392 if (FLAG_debug) {
393 PrintBytes("PC: ", (uintptr_t*)pc);
394 }
395
396 GET_STACK_TRACE_WITH_PC_AND_BP(kStackTraceMax, pc, bp);
397 stack.PrintStack();
398
399 CHECK(AddrIsInMem(addr));
400
401 DescribeAddress(addr, access_size);
402
403 uintptr_t shadow_addr = MemToShadow(addr);
404 Report("ABORTING\n");
405 __asan_print_accumulated_stats();
406 Printf("Shadow byte and word:\n");
407 Printf(" %p: %x\n", shadow_addr, *(unsigned char*)shadow_addr);
408 uintptr_t aligned_shadow = shadow_addr & ~(kWordSize - 1);
409 PrintBytes(" ", (uintptr_t*)(aligned_shadow));
410 Printf("More shadow bytes:\n");
411 PrintBytes(" ", (uintptr_t*)(aligned_shadow-4*kWordSize));
412 PrintBytes(" ", (uintptr_t*)(aligned_shadow-3*kWordSize));
413 PrintBytes(" ", (uintptr_t*)(aligned_shadow-2*kWordSize));
414 PrintBytes(" ", (uintptr_t*)(aligned_shadow-1*kWordSize));
415 PrintBytes("=>", (uintptr_t*)(aligned_shadow+0*kWordSize));
416 PrintBytes(" ", (uintptr_t*)(aligned_shadow+1*kWordSize));
417 PrintBytes(" ", (uintptr_t*)(aligned_shadow+2*kWordSize));
418 PrintBytes(" ", (uintptr_t*)(aligned_shadow+3*kWordSize));
419 PrintBytes(" ", (uintptr_t*)(aligned_shadow+4*kWordSize));
420 if (error_report_callback) {
421 error_report_callback(error_message_buffer);
422 }
423 AsanDie();
424 }
425
__asan_init()426 void __asan_init() {
427 if (asan_inited) return;
428 asan_init_is_running = true;
429
430 // Make sure we are not statically linked.
431 AsanDoesNotSupportStaticLinkage();
432
433 // flags
434 const char *options = AsanGetEnv("ASAN_OPTIONS");
435 FLAG_malloc_context_size =
436 IntFlagValue(options, "malloc_context_size=", kMallocContextSize);
437 CHECK(FLAG_malloc_context_size <= kMallocContextSize);
438
439 FLAG_max_malloc_fill_size =
440 IntFlagValue(options, "max_malloc_fill_size=", 0);
441
442 FLAG_v = IntFlagValue(options, "verbosity=", 0);
443
444 FLAG_redzone = IntFlagValue(options, "redzone=",
445 (ASAN_LOW_MEMORY) ? 64 : 128);
446 CHECK(FLAG_redzone >= 32);
447 CHECK((FLAG_redzone & (FLAG_redzone - 1)) == 0);
448
449 FLAG_atexit = IntFlagValue(options, "atexit=", 0);
450 FLAG_poison_shadow = IntFlagValue(options, "poison_shadow=", 1);
451 FLAG_report_globals = IntFlagValue(options, "report_globals=", 1);
452 FLAG_handle_segv = IntFlagValue(options, "handle_segv=", ASAN_NEEDS_SEGV);
453 FLAG_use_sigaltstack = IntFlagValue(options, "use_sigaltstack=", 0);
454 FLAG_symbolize = IntFlagValue(options, "symbolize=", 1);
455 FLAG_demangle = IntFlagValue(options, "demangle=", 1);
456 FLAG_debug = IntFlagValue(options, "debug=", 0);
457 FLAG_replace_cfallocator = IntFlagValue(options, "replace_cfallocator=", 1);
458 FLAG_replace_str = IntFlagValue(options, "replace_str=", 1);
459 FLAG_replace_intrin = IntFlagValue(options, "replace_intrin=", 1);
460 FLAG_use_fake_stack = IntFlagValue(options, "use_fake_stack=", 1);
461 FLAG_exitcode = IntFlagValue(options, "exitcode=",
462 ASAN_DEFAULT_FAILURE_EXITCODE);
463 FLAG_allow_user_poisoning = IntFlagValue(options,
464 "allow_user_poisoning=", 1);
465 FLAG_sleep_before_dying = IntFlagValue(options, "sleep_before_dying=", 0);
466 FLAG_abort_on_error = IntFlagValue(options, "abort_on_error=", 0);
467 FLAG_unmap_shadow_on_exit = IntFlagValue(options, "unmap_shadow_on_exit=", 0);
468 // By default, disable core dumper on 64-bit --
469 // it makes little sense to dump 16T+ core.
470 FLAG_disable_core = IntFlagValue(options, "disable_core=", __WORDSIZE == 64);
471
472 FLAG_quarantine_size = IntFlagValue(options, "quarantine_size=",
473 (ASAN_LOW_MEMORY) ? 1UL << 24 : 1UL << 28);
474
475 if (FLAG_v) {
476 Report("Parsed ASAN_OPTIONS: %s\n", options);
477 }
478
479 if (FLAG_atexit) {
480 Atexit(asan_atexit);
481 }
482
483 // interceptors
484 InitializeAsanInterceptors();
485
486 ReplaceSystemMalloc();
487 ReplaceOperatorsNewAndDelete();
488
489 if (FLAG_v) {
490 Printf("|| `[%p, %p]` || HighMem ||\n", kHighMemBeg, kHighMemEnd);
491 Printf("|| `[%p, %p]` || HighShadow ||\n",
492 kHighShadowBeg, kHighShadowEnd);
493 Printf("|| `[%p, %p]` || ShadowGap ||\n",
494 kShadowGapBeg, kShadowGapEnd);
495 Printf("|| `[%p, %p]` || LowShadow ||\n",
496 kLowShadowBeg, kLowShadowEnd);
497 Printf("|| `[%p, %p]` || LowMem ||\n", kLowMemBeg, kLowMemEnd);
498 Printf("MemToShadow(shadow): %p %p %p %p\n",
499 MEM_TO_SHADOW(kLowShadowBeg),
500 MEM_TO_SHADOW(kLowShadowEnd),
501 MEM_TO_SHADOW(kHighShadowBeg),
502 MEM_TO_SHADOW(kHighShadowEnd));
503 Printf("red_zone=%zu\n", (size_t)FLAG_redzone);
504 Printf("malloc_context_size=%zu\n", (size_t)FLAG_malloc_context_size);
505
506 Printf("SHADOW_SCALE: %zx\n", (size_t)SHADOW_SCALE);
507 Printf("SHADOW_GRANULARITY: %zx\n", (size_t)SHADOW_GRANULARITY);
508 Printf("SHADOW_OFFSET: %zx\n", (size_t)SHADOW_OFFSET);
509 CHECK(SHADOW_SCALE >= 3 && SHADOW_SCALE <= 7);
510 }
511
512 if (FLAG_disable_core) {
513 AsanDisableCoreDumper();
514 }
515
516 if (AsanShadowRangeIsAvailable()) {
517 if (kLowShadowBeg != kLowShadowEnd) {
518 // mmap the low shadow plus at least one page.
519 ReserveShadowMemoryRange(kLowShadowBeg - kMmapGranularity, kLowShadowEnd);
520 }
521 // mmap the high shadow.
522 ReserveShadowMemoryRange(kHighShadowBeg, kHighShadowEnd);
523 // protect the gap
524 void *prot = AsanMprotect(kShadowGapBeg, kShadowGapEnd - kShadowGapBeg + 1);
525 CHECK(prot == (void*)kShadowGapBeg);
526 } else {
527 Report("Shadow memory range interleaves with an existing memory mapping. "
528 "ASan cannot proceed correctly. ABORTING.\n");
529 AsanDumpProcessMap();
530 AsanDie();
531 }
532
533 InstallSignalHandlers();
534
535 // On Linux AsanThread::ThreadStart() calls malloc() that's why asan_inited
536 // should be set to 1 prior to initializing the threads.
537 asan_inited = 1;
538 asan_init_is_running = false;
539
540 asanThreadRegistry().Init();
541 asanThreadRegistry().GetMain()->ThreadStart();
542 force_interface_symbols(); // no-op.
543
544 if (FLAG_v) {
545 Report("AddressSanitizer Init done\n");
546 }
547 }
548
549 #if defined(ASAN_USE_PREINIT_ARRAY)
550 // On Linux, we force __asan_init to be called before anyone else
551 // by placing it into .preinit_array section.
552 // FIXME: do we have anything like this on Mac?
553 __attribute__((section(".preinit_array")))
554 typeof(__asan_init) *__asan_preinit =__asan_init;
555 #elif defined(_WIN32) && defined(_DLL)
556 // On Windows, when using dynamic CRT (/MD), we can put a pointer
557 // to __asan_init into the global list of C initializers.
558 // See crt0dat.c in the CRT sources for the details.
559 #pragma section(".CRT$XIB", long, read) // NOLINT
560 __declspec(allocate(".CRT$XIB")) void (*__asan_preinit)() = __asan_init;
561 #endif
562