asan_rtl.cc revision fce5bd4cc29fddb5e8f0cb9c12df7c10187a991d 
1//===-- asan_rtl.cc -------------------------------------------------------===//
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#include "sanitizer_common/sanitizer_atomic.h"
25#include "sanitizer_common/sanitizer_libc.h"
26
27namespace __sanitizer {
28using namespace __asan;
29
30void Die() {
31  static atomic_uint32_t num_calls;
32  if (atomic_fetch_add(&num_calls, 1, memory_order_relaxed) != 0) {
33    // Don't die twice - run a busy loop.
34    while (1) { }
35  }
36  if (FLAG_sleep_before_dying) {
37    Report("Sleeping for %zd second(s)\n", FLAG_sleep_before_dying);
38    SleepForSeconds(FLAG_sleep_before_dying);
39  }
40  if (FLAG_unmap_shadow_on_exit)
41    UnmapOrDie((void*)kLowShadowBeg, kHighShadowEnd - kLowShadowBeg);
42  if (death_callback)
43    death_callback();
44  if (FLAG_abort_on_error)
45    Abort();
46  Exit(FLAG_exitcode);
47}
48
49void CheckFailed(const char *file, int line, const char *cond, u64 v1, u64 v2) {
50  AsanReport("AddressSanitizer CHECK failed: %s:%d \"%s\" (%zx, %zx)\n",
51             file, line, cond, (uptr)v1, (uptr)v2);
52  PRINT_CURRENT_STACK();
53  ShowStatsAndAbort();
54}
55
56}  // namespace __sanitizer
57
58namespace __asan {
59
60// -------------------------- Flags ------------------------- {{{1
61static const uptr kMallocContextSize = 30;
62
63uptr  FLAG_malloc_context_size = kMallocContextSize;
64uptr  FLAG_max_malloc_fill_size = 0;
65s64 FLAG_v = 0;
66uptr  FLAG_redzone = (ASAN_LOW_MEMORY) ? 64 : 128;  // power of two, >= 32
67uptr  FLAG_quarantine_size = (ASAN_LOW_MEMORY) ? 1UL << 24 : 1UL << 28;
68static s64    FLAG_atexit = 0;
69bool    FLAG_poison_shadow = 1;
70s64 FLAG_report_globals = 1;
71bool    FLAG_handle_segv = ASAN_NEEDS_SEGV;
72bool    FLAG_use_sigaltstack = 0;
73bool    FLAG_symbolize = 0;
74s64 FLAG_demangle = 1;
75s64 FLAG_debug = 0;
76bool    FLAG_replace_cfallocator = 1;  // Used on Mac only.
77bool    FLAG_mac_ignore_invalid_free = 0;  // Used on Mac only.
78bool    FLAG_replace_str = 1;
79bool    FLAG_replace_intrin = 1;
80bool    FLAG_use_fake_stack = 1;
81s64 FLAG_exitcode = ASAN_DEFAULT_FAILURE_EXITCODE;
82bool    FLAG_allow_user_poisoning = 1;
83s64 FLAG_sleep_before_dying = 0;
84bool    FLAG_abort_on_error = 0;
85bool    FLAG_unmap_shadow_on_exit = 0;
86bool    FLAG_disable_core = __WORDSIZE == 64;
87bool    FLAG_check_malloc_usable_size = 1;
88
89// -------------------------- Globals --------------------- {{{1
90int asan_inited;
91bool asan_init_is_running;
92void (*death_callback)(void);
93static void (*error_report_callback)(const char*);
94char *error_message_buffer = 0;
95uptr error_message_buffer_pos = 0;
96uptr error_message_buffer_size = 0;
97
98// -------------------------- Misc ---------------- {{{1
99void ShowStatsAndAbort() {
100  __asan_print_accumulated_stats();
101  Die();
102}
103
104static void PrintBytes(const char *before, uptr *a) {
105  u8 *bytes = (u8*)a;
106  uptr byte_num = (__WORDSIZE) / 8;
107  AsanPrintf("%s%p:", before, (void*)a);
108  for (uptr i = 0; i < byte_num; i++) {
109    AsanPrintf(" %x%x", bytes[i] >> 4, bytes[i] & 15);
110  }
111  AsanPrintf("\n");
112}
113
114void AppendToErrorMessageBuffer(const char *buffer) {
115  if (error_message_buffer) {
116    uptr length = internal_strlen(buffer);
117    CHECK_GE(error_message_buffer_size, error_message_buffer_pos);
118    uptr remaining = error_message_buffer_size - error_message_buffer_pos;
119    internal_strncpy(error_message_buffer + error_message_buffer_pos,
120                     buffer, remaining);
121    error_message_buffer[error_message_buffer_size - 1] = '\0';
122    // FIXME: reallocate the buffer instead of truncating the message.
123    error_message_buffer_pos += remaining > length ? length : remaining;
124  }
125}
126
127// ---------------------- mmap -------------------- {{{1
128// Reserve memory range [beg, end].
129static void ReserveShadowMemoryRange(uptr beg, uptr end) {
130  CHECK((beg % kPageSize) == 0);
131  CHECK(((end + 1) % kPageSize) == 0);
132  uptr size = end - beg + 1;
133  void *res = MmapFixedNoReserve(beg, size);
134  CHECK(res == (void*)beg && "ReserveShadowMemoryRange failed");
135}
136
137// ---------------------- LowLevelAllocator ------------- {{{1
138void *LowLevelAllocator::Allocate(uptr size) {
139  CHECK((size & (size - 1)) == 0 && "size must be a power of two");
140  if (allocated_end_ - allocated_current_ < (sptr)size) {
141    uptr size_to_allocate = Max(size, kPageSize);
142    allocated_current_ =
143        (char*)MmapOrDie(size_to_allocate, __FUNCTION__);
144    allocated_end_ = allocated_current_ + size_to_allocate;
145    PoisonShadow((uptr)allocated_current_, size_to_allocate,
146                 kAsanInternalHeapMagic);
147  }
148  CHECK(allocated_end_ - allocated_current_ >= (sptr)size);
149  void *res = allocated_current_;
150  allocated_current_ += size;
151  return res;
152}
153
154// ---------------------- DescribeAddress -------------------- {{{1
155static bool DescribeStackAddress(uptr addr, uptr access_size) {
156  AsanThread *t = asanThreadRegistry().FindThreadByStackAddress(addr);
157  if (!t) return false;
158  const sptr kBufSize = 4095;
159  char buf[kBufSize];
160  uptr offset = 0;
161  const char *frame_descr = t->GetFrameNameByAddr(addr, &offset);
162  // This string is created by the compiler and has the following form:
163  // "FunctioName n alloc_1 alloc_2 ... alloc_n"
164  // where alloc_i looks like "offset size len ObjectName ".
165  CHECK(frame_descr);
166  // Report the function name and the offset.
167  const char *name_end = internal_strchr(frame_descr, ' ');
168  CHECK(name_end);
169  buf[0] = 0;
170  internal_strncat(buf, frame_descr,
171                   Min(kBufSize,
172                       static_cast<sptr>(name_end - frame_descr)));
173  AsanPrintf("Address %p is located at offset %zu "
174             "in frame <%s> of T%d's stack:\n",
175             (void*)addr, offset, buf, t->tid());
176  // Report the number of stack objects.
177  char *p;
178  uptr n_objects = internal_simple_strtoll(name_end, &p, 10);
179  CHECK(n_objects > 0);
180  AsanPrintf("  This frame has %zu object(s):\n", n_objects);
181  // Report all objects in this frame.
182  for (uptr i = 0; i < n_objects; i++) {
183    uptr beg, size;
184    sptr len;
185    beg  = internal_simple_strtoll(p, &p, 10);
186    size = internal_simple_strtoll(p, &p, 10);
187    len  = internal_simple_strtoll(p, &p, 10);
188    if (beg <= 0 || size <= 0 || len < 0 || *p != ' ') {
189      AsanPrintf("AddressSanitizer can't parse the stack frame "
190                 "descriptor: |%s|\n", frame_descr);
191      break;
192    }
193    p++;
194    buf[0] = 0;
195    internal_strncat(buf, p, Min(kBufSize, len));
196    p += len;
197    AsanPrintf("    [%zu, %zu) '%s'\n", beg, beg + size, buf);
198  }
199  AsanPrintf("HINT: this may be a false positive if your program uses "
200             "some custom stack unwind mechanism\n"
201             "      (longjmp and C++ exceptions *are* supported)\n");
202  t->summary()->Announce();
203  return true;
204}
205
206static NOINLINE void DescribeAddress(uptr addr, uptr access_size) {
207  // Check if this is a global.
208  if (DescribeAddrIfGlobal(addr))
209    return;
210
211  if (DescribeStackAddress(addr, access_size))
212    return;
213
214  // finally, check if this is a heap.
215  DescribeHeapAddress(addr, access_size);
216}
217
218// -------------------------- Run-time entry ------------------- {{{1
219// exported functions
220#define ASAN_REPORT_ERROR(type, is_write, size)                     \
221extern "C" NOINLINE INTERFACE_ATTRIBUTE                        \
222void __asan_report_ ## type ## size(uptr addr);                \
223void __asan_report_ ## type ## size(uptr addr) {               \
224  GET_CALLER_PC_BP_SP;                                              \
225  __asan_report_error(pc, bp, sp, addr, is_write, size);            \
226}
227
228ASAN_REPORT_ERROR(load, false, 1)
229ASAN_REPORT_ERROR(load, false, 2)
230ASAN_REPORT_ERROR(load, false, 4)
231ASAN_REPORT_ERROR(load, false, 8)
232ASAN_REPORT_ERROR(load, false, 16)
233ASAN_REPORT_ERROR(store, true, 1)
234ASAN_REPORT_ERROR(store, true, 2)
235ASAN_REPORT_ERROR(store, true, 4)
236ASAN_REPORT_ERROR(store, true, 8)
237ASAN_REPORT_ERROR(store, true, 16)
238
239// Force the linker to keep the symbols for various ASan interface functions.
240// We want to keep those in the executable in order to let the instrumented
241// dynamic libraries access the symbol even if it is not used by the executable
242// itself. This should help if the build system is removing dead code at link
243// time.
244static NOINLINE void force_interface_symbols() {
245  volatile int fake_condition = 0;  // prevent dead condition elimination.
246  if (fake_condition) {
247    __asan_report_load1(0);
248    __asan_report_load2(0);
249    __asan_report_load4(0);
250    __asan_report_load8(0);
251    __asan_report_load16(0);
252    __asan_report_store1(0);
253    __asan_report_store2(0);
254    __asan_report_store4(0);
255    __asan_report_store8(0);
256    __asan_report_store16(0);
257    __asan_register_global(0, 0, 0);
258    __asan_register_globals(0, 0);
259    __asan_unregister_globals(0, 0);
260    __asan_set_death_callback(0);
261    __asan_set_error_report_callback(0);
262    __asan_handle_no_return();
263  }
264}
265
266// -------------------------- Init ------------------- {{{1
267static void IntFlagValue(const char *flags, const char *flag,
268                         s64 *out_val) {
269  if (!flags) return;
270  const char *str = internal_strstr(flags, flag);
271  if (!str) return;
272  *out_val = internal_atoll(str + internal_strlen(flag));
273}
274
275static void BoolFlagValue(const char *flags, const char *flag,
276                          bool *out_val) {
277  if (!flags) return;
278  const char *str = internal_strstr(flags, flag);
279  if (!str) return;
280  const char *suffix = str + internal_strlen(flag);
281  if (!internal_atoll(str + internal_strlen(flag))) {
282    if (suffix[0] == '0') {
283      *out_val = false;
284      return;
285    }
286  } else {
287    *out_val = true;
288    return;
289  }
290  switch (suffix[0]) {
291    case 'y':
292    case 't': {
293      *out_val = true;
294      break;
295    }
296    case 'n':
297    case 'f': {
298      *out_val = false;
299      break;
300    }
301    default: return;
302  }
303}
304
305static void asan_atexit() {
306  AsanPrintf("AddressSanitizer exit stats:\n");
307  __asan_print_accumulated_stats();
308}
309
310}  // namespace __asan
311
312// ---------------------- Interface ---------------- {{{1
313using namespace __asan;  // NOLINT
314
315int __asan_set_error_exit_code(int exit_code) {
316  int old = FLAG_exitcode;
317  FLAG_exitcode = exit_code;
318  return old;
319}
320
321void NOINLINE __asan_handle_no_return() {
322  int local_stack;
323  AsanThread *curr_thread = asanThreadRegistry().GetCurrent();
324  CHECK(curr_thread);
325  uptr top = curr_thread->stack_top();
326  uptr bottom = ((uptr)&local_stack - kPageSize) & ~(kPageSize-1);
327  PoisonShadow(bottom, top - bottom, 0);
328}
329
330void NOINLINE __asan_set_death_callback(void (*callback)(void)) {
331  death_callback = callback;
332}
333
334void NOINLINE __asan_set_error_report_callback(void (*callback)(const char*)) {
335  error_report_callback = callback;
336  if (callback) {
337    error_message_buffer_size = 1 << 16;
338    error_message_buffer =
339        (char*)MmapOrDie(error_message_buffer_size, __FUNCTION__);
340    error_message_buffer_pos = 0;
341  }
342}
343
344void __asan_report_error(uptr pc, uptr bp, uptr sp,
345                         uptr addr, bool is_write, uptr access_size) {
346  // Do not print more than one report, otherwise they will mix up.
347  static atomic_uint32_t num_calls;
348  if (atomic_fetch_add(&num_calls, 1, memory_order_relaxed) != 0) return;
349
350  AsanPrintf("===================================================="
351             "=============\n");
352  const char *bug_descr = "unknown-crash";
353  if (AddrIsInMem(addr)) {
354    u8 *shadow_addr = (u8*)MemToShadow(addr);
355    // If we are accessing 16 bytes, look at the second shadow byte.
356    if (*shadow_addr == 0 && access_size > SHADOW_GRANULARITY)
357      shadow_addr++;
358    // If we are in the partial right redzone, look at the next shadow byte.
359    if (*shadow_addr > 0 && *shadow_addr < 128)
360      shadow_addr++;
361    switch (*shadow_addr) {
362      case kAsanHeapLeftRedzoneMagic:
363      case kAsanHeapRightRedzoneMagic:
364        bug_descr = "heap-buffer-overflow";
365        break;
366      case kAsanHeapFreeMagic:
367        bug_descr = "heap-use-after-free";
368        break;
369      case kAsanStackLeftRedzoneMagic:
370        bug_descr = "stack-buffer-underflow";
371        break;
372      case kAsanStackMidRedzoneMagic:
373      case kAsanStackRightRedzoneMagic:
374      case kAsanStackPartialRedzoneMagic:
375        bug_descr = "stack-buffer-overflow";
376        break;
377      case kAsanStackAfterReturnMagic:
378        bug_descr = "stack-use-after-return";
379        break;
380      case kAsanUserPoisonedMemoryMagic:
381        bug_descr = "use-after-poison";
382        break;
383      case kAsanGlobalRedzoneMagic:
384        bug_descr = "global-buffer-overflow";
385        break;
386    }
387  }
388
389  AsanThread *curr_thread = asanThreadRegistry().GetCurrent();
390  u32 curr_tid = asanThreadRegistry().GetCurrentTidOrInvalid();
391
392  if (curr_thread) {
393    // We started reporting an error message. Stop using the fake stack
394    // in case we will call an instrumented function from a symbolizer.
395    curr_thread->fake_stack().StopUsingFakeStack();
396  }
397
398  AsanReport("ERROR: AddressSanitizer %s on address "
399             "%p at pc 0x%zx bp 0x%zx sp 0x%zx\n",
400             bug_descr, (void*)addr, pc, bp, sp);
401
402  AsanPrintf("%s of size %zu at %p thread T%d\n",
403             access_size ? (is_write ? "WRITE" : "READ") : "ACCESS",
404             access_size, (void*)addr, curr_tid);
405
406  if (FLAG_debug) {
407    PrintBytes("PC: ", (uptr*)pc);
408  }
409
410  GET_STACK_TRACE_WITH_PC_AND_BP(kStackTraceMax, pc, bp);
411  stack.PrintStack();
412
413  CHECK(AddrIsInMem(addr));
414
415  DescribeAddress(addr, access_size);
416
417  uptr shadow_addr = MemToShadow(addr);
418  AsanReport("ABORTING\n");
419  __asan_print_accumulated_stats();
420  AsanPrintf("Shadow byte and word:\n");
421  AsanPrintf("  %p: %x\n", (void*)shadow_addr, *(unsigned char*)shadow_addr);
422  uptr aligned_shadow = shadow_addr & ~(kWordSize - 1);
423  PrintBytes("  ", (uptr*)(aligned_shadow));
424  AsanPrintf("More shadow bytes:\n");
425  PrintBytes("  ", (uptr*)(aligned_shadow-4*kWordSize));
426  PrintBytes("  ", (uptr*)(aligned_shadow-3*kWordSize));
427  PrintBytes("  ", (uptr*)(aligned_shadow-2*kWordSize));
428  PrintBytes("  ", (uptr*)(aligned_shadow-1*kWordSize));
429  PrintBytes("=>", (uptr*)(aligned_shadow+0*kWordSize));
430  PrintBytes("  ", (uptr*)(aligned_shadow+1*kWordSize));
431  PrintBytes("  ", (uptr*)(aligned_shadow+2*kWordSize));
432  PrintBytes("  ", (uptr*)(aligned_shadow+3*kWordSize));
433  PrintBytes("  ", (uptr*)(aligned_shadow+4*kWordSize));
434  if (error_report_callback) {
435    error_report_callback(error_message_buffer);
436  }
437  Die();
438}
439
440static void ParseAsanOptions(const char *options) {
441  IntFlagValue(options, "malloc_context_size=",
442               (s64*)&FLAG_malloc_context_size);
443  CHECK(FLAG_malloc_context_size <= kMallocContextSize);
444
445  IntFlagValue(options, "max_malloc_fill_size=",
446               (s64*)&FLAG_max_malloc_fill_size);
447
448  IntFlagValue(options, "verbosity=", &FLAG_v);
449
450  IntFlagValue(options, "redzone=", (s64*)&FLAG_redzone);
451  CHECK(FLAG_redzone >= 16);
452  CHECK(IsPowerOfTwo(FLAG_redzone));
453  IntFlagValue(options, "quarantine_size=", (s64*)&FLAG_quarantine_size);
454
455  IntFlagValue(options, "atexit=", &FLAG_atexit);
456  BoolFlagValue(options, "poison_shadow=", &FLAG_poison_shadow);
457  IntFlagValue(options, "report_globals=", &FLAG_report_globals);
458  BoolFlagValue(options, "handle_segv=", &FLAG_handle_segv);
459  BoolFlagValue(options, "use_sigaltstack=", &FLAG_use_sigaltstack);
460  BoolFlagValue(options, "symbolize=", &FLAG_symbolize);
461  IntFlagValue(options, "demangle=", &FLAG_demangle);
462  IntFlagValue(options, "debug=", &FLAG_debug);
463  BoolFlagValue(options, "replace_cfallocator=", &FLAG_replace_cfallocator);
464  BoolFlagValue(options, "mac_ignore_invalid_free=",
465                &FLAG_mac_ignore_invalid_free);
466  BoolFlagValue(options, "replace_str=", &FLAG_replace_str);
467  BoolFlagValue(options, "replace_intrin=", &FLAG_replace_intrin);
468  BoolFlagValue(options, "use_fake_stack=", &FLAG_use_fake_stack);
469  IntFlagValue(options, "exitcode=", &FLAG_exitcode);
470  BoolFlagValue(options, "allow_user_poisoning=", &FLAG_allow_user_poisoning);
471  IntFlagValue(options, "sleep_before_dying=", &FLAG_sleep_before_dying);
472  BoolFlagValue(options, "abort_on_error=", &FLAG_abort_on_error);
473  BoolFlagValue(options, "unmap_shadow_on_exit=", &FLAG_unmap_shadow_on_exit);
474  // By default, disable core dumper on 64-bit --
475  // it makes little sense to dump 16T+ core.
476  BoolFlagValue(options, "disable_core=", &FLAG_disable_core);
477
478  // Allow the users to work around the bug in Nvidia drivers prior to 295.*.
479  BoolFlagValue(options, "check_malloc_usable_size=",
480                &FLAG_check_malloc_usable_size);
481}
482
483void __asan_init() {
484  if (asan_inited) return;
485  asan_init_is_running = true;
486
487  // Make sure we are not statically linked.
488  AsanDoesNotSupportStaticLinkage();
489
490#if !defined(_WIN32)
491  if (__asan_default_options) {
492    ParseAsanOptions(__asan_default_options);
493    if (FLAG_v) {
494      Report("Using the defaults from __asan_default_options: %s\n",
495             __asan_default_options);
496    }
497  }
498#endif
499  // flags
500  const char *options = GetEnv("ASAN_OPTIONS");
501  ParseAsanOptions(options);
502
503  if (FLAG_v && options) {
504    Report("Parsed ASAN_OPTIONS: %s\n", options);
505  }
506
507  if (FLAG_atexit) {
508    Atexit(asan_atexit);
509  }
510
511  // interceptors
512  InitializeAsanInterceptors();
513
514  ReplaceSystemMalloc();
515  ReplaceOperatorsNewAndDelete();
516
517  if (FLAG_v) {
518    Printf("|| `[%p, %p]` || HighMem    ||\n",
519           (void*)kHighMemBeg, (void*)kHighMemEnd);
520    Printf("|| `[%p, %p]` || HighShadow ||\n",
521           (void*)kHighShadowBeg, (void*)kHighShadowEnd);
522    Printf("|| `[%p, %p]` || ShadowGap  ||\n",
523           (void*)kShadowGapBeg, (void*)kShadowGapEnd);
524    Printf("|| `[%p, %p]` || LowShadow  ||\n",
525           (void*)kLowShadowBeg, (void*)kLowShadowEnd);
526    Printf("|| `[%p, %p]` || LowMem     ||\n",
527           (void*)kLowMemBeg, (void*)kLowMemEnd);
528    Printf("MemToShadow(shadow): %p %p %p %p\n",
529           (void*)MEM_TO_SHADOW(kLowShadowBeg),
530           (void*)MEM_TO_SHADOW(kLowShadowEnd),
531           (void*)MEM_TO_SHADOW(kHighShadowBeg),
532           (void*)MEM_TO_SHADOW(kHighShadowEnd));
533    Printf("red_zone=%zu\n", (uptr)FLAG_redzone);
534    Printf("malloc_context_size=%zu\n", (uptr)FLAG_malloc_context_size);
535
536    Printf("SHADOW_SCALE: %zx\n", (uptr)SHADOW_SCALE);
537    Printf("SHADOW_GRANULARITY: %zx\n", (uptr)SHADOW_GRANULARITY);
538    Printf("SHADOW_OFFSET: %zx\n", (uptr)SHADOW_OFFSET);
539    CHECK(SHADOW_SCALE >= 3 && SHADOW_SCALE <= 7);
540  }
541
542  if (FLAG_disable_core) {
543    DisableCoreDumper();
544  }
545
546  uptr shadow_start = kLowShadowBeg;
547  if (kLowShadowBeg > 0) shadow_start -= kMmapGranularity;
548  uptr shadow_end = kHighShadowEnd;
549  if (MemoryRangeIsAvailable(shadow_start, shadow_end)) {
550    if (kLowShadowBeg != kLowShadowEnd) {
551      // mmap the low shadow plus at least one page.
552      ReserveShadowMemoryRange(kLowShadowBeg - kMmapGranularity, kLowShadowEnd);
553    }
554    // mmap the high shadow.
555    ReserveShadowMemoryRange(kHighShadowBeg, kHighShadowEnd);
556    // protect the gap
557    void *prot = Mprotect(kShadowGapBeg, kShadowGapEnd - kShadowGapBeg + 1);
558    CHECK(prot == (void*)kShadowGapBeg);
559  } else {
560    Report("Shadow memory range interleaves with an existing memory mapping. "
561           "ASan cannot proceed correctly. ABORTING.\n");
562    DumpProcessMap();
563    Die();
564  }
565
566  InstallSignalHandlers();
567
568  // On Linux AsanThread::ThreadStart() calls malloc() that's why asan_inited
569  // should be set to 1 prior to initializing the threads.
570  asan_inited = 1;
571  asan_init_is_running = false;
572
573  asanThreadRegistry().Init();
574  asanThreadRegistry().GetMain()->ThreadStart();
575  force_interface_symbols();  // no-op.
576
577  if (FLAG_v) {
578    Report("AddressSanitizer Init done\n");
579  }
580}
581
582#if defined(ASAN_USE_PREINIT_ARRAY)
583  // On Linux, we force __asan_init to be called before anyone else
584  // by placing it into .preinit_array section.
585  // FIXME: do we have anything like this on Mac?
586  __attribute__((section(".preinit_array")))
587    typeof(__asan_init) *__asan_preinit =__asan_init;
588#elif defined(_WIN32) && defined(_DLL)
589  // On Windows, when using dynamic CRT (/MD), we can put a pointer
590  // to __asan_init into the global list of C initializers.
591  // See crt0dat.c in the CRT sources for the details.
592  #pragma section(".CRT$XIB", long, read)  // NOLINT
593  __declspec(allocate(".CRT$XIB")) void (*__asan_preinit)() = __asan_init;
594#endif
595