ydb-oss sync: add clang16-rt/ to additionalPathsToCopy

1 files changed, 1457 insertions, 0 deletions

diff --git a/contrib/libs/clang16-rt/lib/sanitizer_common/sanitizer_mac.cpp b/contrib/libs/clang16-rt/lib/sanitizer_common/sanitizer_mac.cpp
new file mode 100644
index 0000000000..23c4c6619d
--- /dev/null
+++ b/contrib/libs/clang16-rt/lib/sanitizer_common/sanitizer_mac.cpp
@@ -0,0 +1,1457 @@
+//===-- sanitizer_mac.cpp -------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file is shared between various sanitizers' runtime libraries and
+// implements OSX-specific functions.
+//===----------------------------------------------------------------------===//
+
+#include "sanitizer_platform.h"
+#if SANITIZER_APPLE
+#include "sanitizer_mac.h"
+#include "interception/interception.h"
+
+// Use 64-bit inodes in file operations. ASan does not support OS X 10.5, so
+// the clients will most certainly use 64-bit ones as well.
+#ifndef _DARWIN_USE_64_BIT_INODE
+#define _DARWIN_USE_64_BIT_INODE 1
+#endif
+#include <stdio.h>
+
+#include "sanitizer_common.h"
+#include "sanitizer_file.h"
+#include "sanitizer_flags.h"
+#include "sanitizer_interface_internal.h"
+#include "sanitizer_internal_defs.h"
+#include "sanitizer_libc.h"
+#include "sanitizer_platform_limits_posix.h"
+#include "sanitizer_procmaps.h"
+#include "sanitizer_ptrauth.h"
+
+#if !SANITIZER_IOS
+#include <crt_externs.h>  // for _NSGetEnviron
+#else
+extern char **environ;
+#endif
+
+#if defined(__has_include) && __has_include(<os/trace.h>)
+#define SANITIZER_OS_TRACE 1
+#include <os/trace.h>
+#else
+#define SANITIZER_OS_TRACE 0
+#endif
+
+// import new crash reporting api
+#if defined(__has_include) && __has_include(<CrashReporterClient.h>)
+#define HAVE_CRASHREPORTERCLIENT_H 1
+#include <CrashReporterClient.h>
+#else
+#define HAVE_CRASHREPORTERCLIENT_H 0
+#endif
+
+#if !SANITIZER_IOS
+#include <crt_externs.h>  // for _NSGetArgv and _NSGetEnviron
+#else
+extern "C" {
+  extern char ***_NSGetArgv(void);
+}
+#endif
+
+#include <asl.h>
+#include <dlfcn.h>  // for dladdr()
+#include <errno.h>
+#include <fcntl.h>
+#include <libkern/OSAtomic.h>
+#include <mach-o/dyld.h>
+#include <mach/mach.h>
+#include <mach/mach_time.h>
+#include <mach/vm_statistics.h>
+#include <malloc/malloc.h>
+#include <os/log.h>
+#include <pthread.h>
+#include <pthread/introspection.h>
+#include <sched.h>
+#include <signal.h>
+#include <spawn.h>
+#include <stdlib.h>
+#include <sys/ioctl.h>
+#include <sys/mman.h>
+#include <sys/resource.h>
+#include <sys/stat.h>
+#include <sys/sysctl.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include <util.h>
+
+// From <crt_externs.h>, but we don't have that file on iOS.
+extern "C" {
+  extern char ***_NSGetArgv(void);
+  extern char ***_NSGetEnviron(void);
+}
+
+// From <mach/mach_vm.h>, but we don't have that file on iOS.
+extern "C" {
+  extern kern_return_t mach_vm_region_recurse(
+    vm_map_t target_task,
+    mach_vm_address_t *address,
+    mach_vm_size_t *size,
+    natural_t *nesting_depth,
+    vm_region_recurse_info_t info,
+    mach_msg_type_number_t *infoCnt);
+}
+
+namespace __sanitizer {
+
+#include "sanitizer_syscall_generic.inc"
+
+// Direct syscalls, don't call libmalloc hooks (but not available on 10.6).
+extern "C" void *__mmap(void *addr, size_t len, int prot, int flags, int fildes,
+                        off_t off) SANITIZER_WEAK_ATTRIBUTE;
+extern "C" int __munmap(void *, size_t) SANITIZER_WEAK_ATTRIBUTE;
+
+// ---------------------- sanitizer_libc.h
+
+// From <mach/vm_statistics.h>, but not on older OSs.
+#ifndef VM_MEMORY_SANITIZER
+#define VM_MEMORY_SANITIZER 99
+#endif
+
+// XNU on Darwin provides a mmap flag that optimizes allocation/deallocation of
+// giant memory regions (i.e. shadow memory regions).
+#define kXnuFastMmapFd 0x4
+static size_t kXnuFastMmapThreshold = 2 << 30; // 2 GB
+static bool use_xnu_fast_mmap = false;
+
+uptr internal_mmap(void *addr, size_t length, int prot, int flags,
+                   int fd, u64 offset) {
+  if (fd == -1) {
+    fd = VM_MAKE_TAG(VM_MEMORY_SANITIZER);
+    if (length >= kXnuFastMmapThreshold) {
+      if (use_xnu_fast_mmap) fd |= kXnuFastMmapFd;
+    }
+  }
+  if (&__mmap) return (uptr)__mmap(addr, length, prot, flags, fd, offset);
+  return (uptr)mmap(addr, length, prot, flags, fd, offset);
+}
+
+uptr internal_munmap(void *addr, uptr length) {
+  if (&__munmap) return __munmap(addr, length);
+  return munmap(addr, length);
+}
+
+uptr internal_mremap(void *old_address, uptr old_size, uptr new_size, int flags,
+                     void *new_address) {
+  CHECK(false && "internal_mremap is unimplemented on Mac");
+  return 0;
+}
+
+int internal_mprotect(void *addr, uptr length, int prot) {
+  return mprotect(addr, length, prot);
+}
+
+int internal_madvise(uptr addr, uptr length, int advice) {
+  return madvise((void *)addr, length, advice);
+}
+
+uptr internal_close(fd_t fd) {
+  return close(fd);
+}
+
+uptr internal_open(const char *filename, int flags) {
+  return open(filename, flags);
+}
+
+uptr internal_open(const char *filename, int flags, u32 mode) {
+  return open(filename, flags, mode);
+}
+
+uptr internal_read(fd_t fd, void *buf, uptr count) {
+  return read(fd, buf, count);
+}
+
+uptr internal_write(fd_t fd, const void *buf, uptr count) {
+  return write(fd, buf, count);
+}
+
+uptr internal_stat(const char *path, void *buf) {
+  return stat(path, (struct stat *)buf);
+}
+
+uptr internal_lstat(const char *path, void *buf) {
+  return lstat(path, (struct stat *)buf);
+}
+
+uptr internal_fstat(fd_t fd, void *buf) {
+  return fstat(fd, (struct stat *)buf);
+}
+
+uptr internal_filesize(fd_t fd) {
+  struct stat st;
+  if (internal_fstat(fd, &st))
+    return -1;
+  return (uptr)st.st_size;
+}
+
+uptr internal_dup(int oldfd) {
+  return dup(oldfd);
+}
+
+uptr internal_dup2(int oldfd, int newfd) {
+  return dup2(oldfd, newfd);
+}
+
+uptr internal_readlink(const char *path, char *buf, uptr bufsize) {
+  return readlink(path, buf, bufsize);
+}
+
+uptr internal_unlink(const char *path) {
+  return unlink(path);
+}
+
+uptr internal_sched_yield() {
+  return sched_yield();
+}
+
+void internal__exit(int exitcode) {
+  _exit(exitcode);
+}
+
+void internal_usleep(u64 useconds) { usleep(useconds); }
+
+uptr internal_getpid() {
+  return getpid();
+}
+
+int internal_dlinfo(void *handle, int request, void *p) {
+  UNIMPLEMENTED();
+}
+
+int internal_sigaction(int signum, const void *act, void *oldact) {
+  return sigaction(signum,
+                   (const struct sigaction *)act, (struct sigaction *)oldact);
+}
+
+void internal_sigfillset(__sanitizer_sigset_t *set) { sigfillset(set); }
+
+uptr internal_sigprocmask(int how, __sanitizer_sigset_t *set,
+                          __sanitizer_sigset_t *oldset) {
+  // Don't use sigprocmask here, because it affects all threads.
+  return pthread_sigmask(how, set, oldset);
+}
+
+// Doesn't call pthread_atfork() handlers (but not available on 10.6).
+extern "C" pid_t __fork(void) SANITIZER_WEAK_ATTRIBUTE;
+
+int internal_fork() {
+  if (&__fork)
+    return __fork();
+  return fork();
+}
+
+int internal_sysctl(const int *name, unsigned int namelen, void *oldp,
+                    uptr *oldlenp, const void *newp, uptr newlen) {
+  return sysctl(const_cast<int *>(name), namelen, oldp, (size_t *)oldlenp,
+                const_cast<void *>(newp), (size_t)newlen);
+}
+
+int internal_sysctlbyname(const char *sname, void *oldp, uptr *oldlenp,
+                          const void *newp, uptr newlen) {
+  return sysctlbyname(sname, oldp, (size_t *)oldlenp, const_cast<void *>(newp),
+                      (size_t)newlen);
+}
+
+static fd_t internal_spawn_impl(const char *argv[], const char *envp[],
+                                pid_t *pid) {
+  fd_t primary_fd = kInvalidFd;
+  fd_t secondary_fd = kInvalidFd;
+
+  auto fd_closer = at_scope_exit([&] {
+    internal_close(primary_fd);
+    internal_close(secondary_fd);
+  });
+
+  // We need a new pseudoterminal to avoid buffering problems. The 'atos' tool
+  // in particular detects when it's talking to a pipe and forgets to flush the
+  // output stream after sending a response.
+  primary_fd = posix_openpt(O_RDWR);
+  if (primary_fd == kInvalidFd)
+    return kInvalidFd;
+
+  int res = grantpt(primary_fd) || unlockpt(primary_fd);
+  if (res != 0) return kInvalidFd;
+
+  // Use TIOCPTYGNAME instead of ptsname() to avoid threading problems.
+  char secondary_pty_name[128];
+  res = ioctl(primary_fd, TIOCPTYGNAME, secondary_pty_name);
+  if (res == -1) return kInvalidFd;
+
+  secondary_fd = internal_open(secondary_pty_name, O_RDWR);
+  if (secondary_fd == kInvalidFd)
+    return kInvalidFd;
+
+  // File descriptor actions
+  posix_spawn_file_actions_t acts;
+  res = posix_spawn_file_actions_init(&acts);
+  if (res != 0) return kInvalidFd;
+
+  auto acts_cleanup = at_scope_exit([&] {
+    posix_spawn_file_actions_destroy(&acts);
+  });
+
+  res = posix_spawn_file_actions_adddup2(&acts, secondary_fd, STDIN_FILENO) ||
+        posix_spawn_file_actions_adddup2(&acts, secondary_fd, STDOUT_FILENO) ||
+        posix_spawn_file_actions_addclose(&acts, secondary_fd);
+  if (res != 0) return kInvalidFd;
+
+  // Spawn attributes
+  posix_spawnattr_t attrs;
+  res = posix_spawnattr_init(&attrs);
+  if (res != 0) return kInvalidFd;
+
+  auto attrs_cleanup  = at_scope_exit([&] {
+    posix_spawnattr_destroy(&attrs);
+  });
+
+  // In the spawned process, close all file descriptors that are not explicitly
+  // described by the file actions object. This is Darwin-specific extension.
+  res = posix_spawnattr_setflags(&attrs, POSIX_SPAWN_CLOEXEC_DEFAULT);
+  if (res != 0) return kInvalidFd;
+
+  // posix_spawn
+  char **argv_casted = const_cast<char **>(argv);
+  char **envp_casted = const_cast<char **>(envp);
+  res = posix_spawn(pid, argv[0], &acts, &attrs, argv_casted, envp_casted);
+  if (res != 0) return kInvalidFd;
+
+  // Disable echo in the new terminal, disable CR.
+  struct termios termflags;
+  tcgetattr(primary_fd, &termflags);
+  termflags.c_oflag &= ~ONLCR;
+  termflags.c_lflag &= ~ECHO;
+  tcsetattr(primary_fd, TCSANOW, &termflags);
+
+  // On success, do not close primary_fd on scope exit.
+  fd_t fd = primary_fd;
+  primary_fd = kInvalidFd;
+
+  return fd;
+}
+
+fd_t internal_spawn(const char *argv[], const char *envp[], pid_t *pid) {
+  // The client program may close its stdin and/or stdout and/or stderr thus
+  // allowing open/posix_openpt to reuse file descriptors 0, 1 or 2. In this
+  // case the communication is broken if either the parent or the child tries to
+  // close or duplicate these descriptors. We temporarily reserve these
+  // descriptors here to prevent this.
+  fd_t low_fds[3];
+  size_t count = 0;
+
+  for (; count < 3; count++) {
+    low_fds[count] = posix_openpt(O_RDWR);
+    if (low_fds[count] >= STDERR_FILENO)
+      break;
+  }
+
+  fd_t fd = internal_spawn_impl(argv, envp, pid);
+
+  for (; count > 0; count--) {
+    internal_close(low_fds[count]);
+  }
+
+  return fd;
+}
+
+uptr internal_rename(const char *oldpath, const char *newpath) {
+  return rename(oldpath, newpath);
+}
+
+uptr internal_ftruncate(fd_t fd, uptr size) {
+  return ftruncate(fd, size);
+}
+
+uptr internal_execve(const char *filename, char *const argv[],
+                     char *const envp[]) {
+  return execve(filename, argv, envp);
+}
+
+uptr internal_waitpid(int pid, int *status, int options) {
+  return waitpid(pid, status, options);
+}
+
+// ----------------- sanitizer_common.h
+bool FileExists(const char *filename) {
+  if (ShouldMockFailureToOpen(filename))
+    return false;
+  struct stat st;
+  if (stat(filename, &st))
+    return false;
+  // Sanity check: filename is a regular file.
+  return S_ISREG(st.st_mode);
+}
+
+bool DirExists(const char *path) {
+  struct stat st;
+  if (stat(path, &st))
+    return false;
+  return S_ISDIR(st.st_mode);
+}
+
+tid_t GetTid() {
+  tid_t tid;
+  pthread_threadid_np(nullptr, &tid);
+  return tid;
+}
+
+void GetThreadStackTopAndBottom(bool at_initialization, uptr *stack_top,
+                                uptr *stack_bottom) {
+  CHECK(stack_top);
+  CHECK(stack_bottom);
+  uptr stacksize = pthread_get_stacksize_np(pthread_self());
+  // pthread_get_stacksize_np() returns an incorrect stack size for the main
+  // thread on Mavericks. See
+  // https://github.com/google/sanitizers/issues/261
+  if ((GetMacosAlignedVersion() >= MacosVersion(10, 9)) && at_initialization &&
+      stacksize == (1 << 19))  {
+    struct rlimit rl;
+    CHECK_EQ(getrlimit(RLIMIT_STACK, &rl), 0);
+    // Most often rl.rlim_cur will be the desired 8M.
+    if (rl.rlim_cur < kMaxThreadStackSize) {
+      stacksize = rl.rlim_cur;
+    } else {
+      stacksize = kMaxThreadStackSize;
+    }
+  }
+  void *stackaddr = pthread_get_stackaddr_np(pthread_self());
+  *stack_top = (uptr)stackaddr;
+  *stack_bottom = *stack_top - stacksize;
+}
+
+char **GetEnviron() {
+#if !SANITIZER_IOS
+  char ***env_ptr = _NSGetEnviron();
+  if (!env_ptr) {
+    Report("_NSGetEnviron() returned NULL. Please make sure __asan_init() is "
+           "called after libSystem_initializer().\n");
+    CHECK(env_ptr);
+  }
+  char **environ = *env_ptr;
+#endif
+  CHECK(environ);
+  return environ;
+}
+
+const char *GetEnv(const char *name) {
+  char **env = GetEnviron();
+  uptr name_len = internal_strlen(name);
+  while (*env != 0) {
+    uptr len = internal_strlen(*env);
+    if (len > name_len) {
+      const char *p = *env;
+      if (!internal_memcmp(p, name, name_len) &&
+          p[name_len] == '=') {  // Match.
+        return *env + name_len + 1;  // String starting after =.
+      }
+    }
+    env++;
+  }
+  return 0;
+}
+
+uptr ReadBinaryName(/*out*/char *buf, uptr buf_len) {
+  CHECK_LE(kMaxPathLength, buf_len);
+
+  // On OS X the executable path is saved to the stack by dyld. Reading it
+  // from there is much faster than calling dladdr, especially for large
+  // binaries with symbols.
+  InternalMmapVector<char> exe_path(kMaxPathLength);
+  uint32_t size = exe_path.size();
+  if (_NSGetExecutablePath(exe_path.data(), &size) == 0 &&
+      realpath(exe_path.data(), buf) != 0) {
+    return internal_strlen(buf);
+  }
+  return 0;
+}
+
+uptr ReadLongProcessName(/*out*/char *buf, uptr buf_len) {
+  return ReadBinaryName(buf, buf_len);
+}
+
+void ReExec() {
+  UNIMPLEMENTED();
+}
+
+void CheckASLR() {
+  // Do nothing
+}
+
+void CheckMPROTECT() {
+  // Do nothing
+}
+
+uptr GetPageSize() {
+  return sysconf(_SC_PAGESIZE);
+}
+
+extern "C" unsigned malloc_num_zones;
+extern "C" malloc_zone_t **malloc_zones;
+malloc_zone_t sanitizer_zone;
+
+// We need to make sure that sanitizer_zone is registered as malloc_zones[0]. If
+// libmalloc tries to set up a different zone as malloc_zones[0], it will call
+// mprotect(malloc_zones, ..., PROT_READ).  This interceptor will catch that and
+// make sure we are still the first (default) zone.
+void MprotectMallocZones(void *addr, int prot) {
+  if (addr == malloc_zones && prot == PROT_READ) {
+    if (malloc_num_zones > 1 && malloc_zones[0] != &sanitizer_zone) {
+      for (unsigned i = 1; i < malloc_num_zones; i++) {
+        if (malloc_zones[i] == &sanitizer_zone) {
+          // Swap malloc_zones[0] and malloc_zones[i].
+          malloc_zones[i] = malloc_zones[0];
+          malloc_zones[0] = &sanitizer_zone;
+          break;
+        }
+      }
+    }
+  }
+}
+
+void FutexWait(atomic_uint32_t *p, u32 cmp) {
+  // FIXME: implement actual blocking.
+  sched_yield();
+}
+
+void FutexWake(atomic_uint32_t *p, u32 count) {}
+
+u64 NanoTime() {
+  timeval tv;
+  internal_memset(&tv, 0, sizeof(tv));
+  gettimeofday(&tv, 0);
+  return (u64)tv.tv_sec * 1000*1000*1000 + tv.tv_usec * 1000;
+}
+
+// This needs to be called during initialization to avoid being racy.
+u64 MonotonicNanoTime() {
+  static mach_timebase_info_data_t timebase_info;
+  if (timebase_info.denom == 0) mach_timebase_info(&timebase_info);
+  return (mach_absolute_time() * timebase_info.numer) / timebase_info.denom;
+}
+
+uptr GetTlsSize() {
+  return 0;
+}
+
+void InitTlsSize() {
+}
+
+uptr TlsBaseAddr() {
+  uptr segbase = 0;
+#if defined(__x86_64__)
+  asm("movq %%gs:0,%0" : "=r"(segbase));
+#elif defined(__i386__)
+  asm("movl %%gs:0,%0" : "=r"(segbase));
+#elif defined(__aarch64__)
+  asm("mrs %x0, tpidrro_el0" : "=r"(segbase));
+  segbase &= 0x07ul;  // clearing lower bits, cpu id stored there
+#endif
+  return segbase;
+}
+
+// The size of the tls on darwin does not appear to be well documented,
+// however the vm memory map suggests that it is 1024 uptrs in size,
+// with a size of 0x2000 bytes on x86_64 and 0x1000 bytes on i386.
+uptr TlsSize() {
+#if defined(__x86_64__) || defined(__i386__)
+  return 1024 * sizeof(uptr);
+#else
+  return 0;
+#endif
+}
+
+void GetThreadStackAndTls(bool main, uptr *stk_addr, uptr *stk_size,
+                          uptr *tls_addr, uptr *tls_size) {
+#if !SANITIZER_GO
+  uptr stack_top, stack_bottom;
+  GetThreadStackTopAndBottom(main, &stack_top, &stack_bottom);
+  *stk_addr = stack_bottom;
+  *stk_size = stack_top - stack_bottom;
+  *tls_addr = TlsBaseAddr();
+  *tls_size = TlsSize();
+#else
+  *stk_addr = 0;
+  *stk_size = 0;
+  *tls_addr = 0;
+  *tls_size = 0;
+#endif
+}
+
+void ListOfModules::init() {
+  clearOrInit();
+  MemoryMappingLayout memory_mapping(false);
+  memory_mapping.DumpListOfModules(&modules_);
+}
+
+void ListOfModules::fallbackInit() { clear(); }
+
+static HandleSignalMode GetHandleSignalModeImpl(int signum) {
+  switch (signum) {
+    case SIGABRT:
+      return common_flags()->handle_abort;
+    case SIGILL:
+      return common_flags()->handle_sigill;
+    case SIGTRAP:
+      return common_flags()->handle_sigtrap;
+    case SIGFPE:
+      return common_flags()->handle_sigfpe;
+    case SIGSEGV:
+      return common_flags()->handle_segv;
+    case SIGBUS:
+      return common_flags()->handle_sigbus;
+  }
+  return kHandleSignalNo;
+}
+
+HandleSignalMode GetHandleSignalMode(int signum) {
+  // Handling fatal signals on watchOS and tvOS devices is disallowed.
+  if ((SANITIZER_WATCHOS || SANITIZER_TVOS) && !(SANITIZER_IOSSIM))
+    return kHandleSignalNo;
+  HandleSignalMode result = GetHandleSignalModeImpl(signum);
+  if (result == kHandleSignalYes && !common_flags()->allow_user_segv_handler)
+    return kHandleSignalExclusive;
+  return result;
+}
+
+// Offset example:
+// XNU 17 -- macOS 10.13 -- iOS 11 -- tvOS 11 -- watchOS 4
+constexpr u16 GetOSMajorKernelOffset() {
+  if (TARGET_OS_OSX) return 4;
+  if (TARGET_OS_IOS || TARGET_OS_TV) return 6;
+  if (TARGET_OS_WATCH) return 13;
+}
+
+using VersStr = char[64];
+
+static uptr ApproximateOSVersionViaKernelVersion(VersStr vers) {
+  u16 kernel_major = GetDarwinKernelVersion().major;
+  u16 offset = GetOSMajorKernelOffset();
+  CHECK_GE(kernel_major, offset);
+  u16 os_major = kernel_major - offset;
+
+  const char *format = "%d.0";
+  if (TARGET_OS_OSX) {
+    if (os_major >= 16) {  // macOS 11+
+      os_major -= 5;
+    } else {  // macOS 10.15 and below
+      format = "10.%d";
+    }
+  }
+  return internal_snprintf(vers, sizeof(VersStr), format, os_major);
+}
+
+static void GetOSVersion(VersStr vers) {
+  uptr len = sizeof(VersStr);
+  if (SANITIZER_IOSSIM) {
+    const char *vers_env = GetEnv("SIMULATOR_RUNTIME_VERSION");
+    if (!vers_env) {
+      Report("ERROR: Running in simulator but SIMULATOR_RUNTIME_VERSION env "
+          "var is not set.\n");
+      Die();
+    }
+    len = internal_strlcpy(vers, vers_env, len);
+  } else {
+    int res =
+        internal_sysctlbyname("kern.osproductversion", vers, &len, nullptr, 0);
+
+    // XNU 17 (macOS 10.13) and below do not provide the sysctl
+    // `kern.osproductversion` entry (res != 0).
+    bool no_os_version = res != 0;
+
+    // For launchd, sanitizer initialization runs before sysctl is setup
+    // (res == 0 && len != strlen(vers), vers is not a valid version).  However,
+    // the kernel version `kern.osrelease` is available.
+    bool launchd = (res == 0 && internal_strlen(vers) < 3);
+    if (launchd) CHECK_EQ(internal_getpid(), 1);
+
+    if (no_os_version || launchd) {
+      len = ApproximateOSVersionViaKernelVersion(vers);
+    }
+  }
+  CHECK_LT(len, sizeof(VersStr));
+}
+
+void ParseVersion(const char *vers, u16 *major, u16 *minor) {
+  // Format: <major>.<minor>[.<patch>]\0
+  CHECK_GE(internal_strlen(vers), 3);
+  const char *p = vers;
+  *major = internal_simple_strtoll(p, &p, /*base=*/10);
+  CHECK_EQ(*p, '.');
+  p += 1;
+  *minor = internal_simple_strtoll(p, &p, /*base=*/10);
+}
+
+// Aligned versions example:
+// macOS 10.15 -- iOS 13 -- tvOS 13 -- watchOS 6
+static void MapToMacos(u16 *major, u16 *minor) {
+  if (TARGET_OS_OSX)
+    return;
+
+  if (TARGET_OS_IOS || TARGET_OS_TV)
+    *major += 2;
+  else if (TARGET_OS_WATCH)
+    *major += 9;
+  else
+    UNREACHABLE("unsupported platform");
+
+  if (*major >= 16) {  // macOS 11+
+    *major -= 5;
+  } else {  // macOS 10.15 and below
+    *minor = *major;
+    *major = 10;
+  }
+}
+
+static MacosVersion GetMacosAlignedVersionInternal() {
+  VersStr vers = {};
+  GetOSVersion(vers);
+
+  u16 major, minor;
+  ParseVersion(vers, &major, &minor);
+  MapToMacos(&major, &minor);
+
+  return MacosVersion(major, minor);
+}
+
+static_assert(sizeof(MacosVersion) == sizeof(atomic_uint32_t::Type),
+              "MacosVersion cache size");
+static atomic_uint32_t cached_macos_version;
+
+MacosVersion GetMacosAlignedVersion() {
+  atomic_uint32_t::Type result =
+      atomic_load(&cached_macos_version, memory_order_acquire);
+  if (!result) {
+    MacosVersion version = GetMacosAlignedVersionInternal();
+    result = *reinterpret_cast<atomic_uint32_t::Type *>(&version);
+    atomic_store(&cached_macos_version, result, memory_order_release);
+  }
+  return *reinterpret_cast<MacosVersion *>(&result);
+}
+
+DarwinKernelVersion GetDarwinKernelVersion() {
+  VersStr vers = {};
+  uptr len = sizeof(VersStr);
+  int res = internal_sysctlbyname("kern.osrelease", vers, &len, nullptr, 0);
+  CHECK_EQ(res, 0);
+  CHECK_LT(len, sizeof(VersStr));
+
+  u16 major, minor;
+  ParseVersion(vers, &major, &minor);
+
+  return DarwinKernelVersion(major, minor);
+}
+
+uptr GetRSS() {
+  struct task_basic_info info;
+  unsigned count = TASK_BASIC_INFO_COUNT;
+  kern_return_t result =
+      task_info(mach_task_self(), TASK_BASIC_INFO, (task_info_t)&info, &count);
+  if (UNLIKELY(result != KERN_SUCCESS)) {
+    Report("Cannot get task info. Error: %d\n", result);
+    Die();
+  }
+  return info.resident_size;
+}
+
+void *internal_start_thread(void *(*func)(void *arg), void *arg) {
+  // Start the thread with signals blocked, otherwise it can steal user signals.
+  __sanitizer_sigset_t set, old;
+  internal_sigfillset(&set);
+  internal_sigprocmask(SIG_SETMASK, &set, &old);
+  pthread_t th;
+  pthread_create(&th, 0, func, arg);
+  internal_sigprocmask(SIG_SETMASK, &old, 0);
+  return th;
+}
+
+void internal_join_thread(void *th) { pthread_join((pthread_t)th, 0); }
+
+#if !SANITIZER_GO
+static Mutex syslog_lock;
+#  endif
+
+void WriteOneLineToSyslog(const char *s) {
+#if !SANITIZER_GO
+  syslog_lock.CheckLocked();
+  if (GetMacosAlignedVersion() >= MacosVersion(10, 12)) {
+    os_log_error(OS_LOG_DEFAULT, "%{public}s", s);
+  } else {
+    asl_log(nullptr, nullptr, ASL_LEVEL_ERR, "%s", s);
+  }
+#endif
+}
+
+// buffer to store crash report application information
+static char crashreporter_info_buff[__sanitizer::kErrorMessageBufferSize] = {};
+static Mutex crashreporter_info_mutex;
+
+extern "C" {
+// Integrate with crash reporter libraries.
+#if HAVE_CRASHREPORTERCLIENT_H
+CRASH_REPORTER_CLIENT_HIDDEN
+struct crashreporter_annotations_t gCRAnnotations
+    __attribute__((section("__DATA," CRASHREPORTER_ANNOTATIONS_SECTION))) = {
+        CRASHREPORTER_ANNOTATIONS_VERSION,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+#if CRASHREPORTER_ANNOTATIONS_VERSION > 4
+        0,
+#endif
+};
+
+#else
+// fall back to old crashreporter api
+static const char *__crashreporter_info__ __attribute__((__used__)) =
+    &crashreporter_info_buff[0];
+asm(".desc ___crashreporter_info__, 0x10");
+#endif
+
+}  // extern "C"
+
+static void CRAppendCrashLogMessage(const char *msg) {
+  Lock l(&crashreporter_info_mutex);
+  internal_strlcat(crashreporter_info_buff, msg,
+                   sizeof(crashreporter_info_buff));
+#if HAVE_CRASHREPORTERCLIENT_H
+  (void)CRSetCrashLogMessage(crashreporter_info_buff);
+#endif
+}
+
+void LogMessageOnPrintf(const char *str) {
+  // Log all printf output to CrashLog.
+  if (common_flags()->abort_on_error)
+    CRAppendCrashLogMessage(str);
+}
+
+void LogFullErrorReport(const char *buffer) {
+#if !SANITIZER_GO
+  // Log with os_trace. This will make it into the crash log.
+#if SANITIZER_OS_TRACE
+  if (GetMacosAlignedVersion() >= MacosVersion(10, 10)) {
+    // os_trace requires the message (format parameter) to be a string literal.
+    if (internal_strncmp(SanitizerToolName, "AddressSanitizer",
+                         sizeof("AddressSanitizer") - 1) == 0)
+      os_trace("Address Sanitizer reported a failure.");
+    else if (internal_strncmp(SanitizerToolName, "UndefinedBehaviorSanitizer",
+                              sizeof("UndefinedBehaviorSanitizer") - 1) == 0)
+      os_trace("Undefined Behavior Sanitizer reported a failure.");
+    else if (internal_strncmp(SanitizerToolName, "ThreadSanitizer",
+                              sizeof("ThreadSanitizer") - 1) == 0)
+      os_trace("Thread Sanitizer reported a failure.");
+    else
+      os_trace("Sanitizer tool reported a failure.");
+
+    if (common_flags()->log_to_syslog)
+      os_trace("Consult syslog for more information.");
+  }
+#endif
+
+  // Log to syslog.
+  // The logging on OS X may call pthread_create so we need the threading
+  // environment to be fully initialized. Also, this should never be called when
+  // holding the thread registry lock since that may result in a deadlock. If
+  // the reporting thread holds the thread registry mutex, and asl_log waits
+  // for GCD to dispatch a new thread, the process will deadlock, because the
+  // pthread_create wrapper needs to acquire the lock as well.
+  Lock l(&syslog_lock);
+  if (common_flags()->log_to_syslog)
+    WriteToSyslog(buffer);
+
+  // The report is added to CrashLog as part of logging all of Printf output.
+#endif
+}
+
+SignalContext::WriteFlag SignalContext::GetWriteFlag() const {
+#if defined(__x86_64__) || defined(__i386__)
+  ucontext_t *ucontext = static_cast<ucontext_t*>(context);
+  return ucontext->uc_mcontext->__es.__err & 2 /*T_PF_WRITE*/ ? Write : Read;
+#elif defined(__arm64__)
+  ucontext_t *ucontext = static_cast<ucontext_t*>(context);
+  return ucontext->uc_mcontext->__es.__esr & 0x40 /*ISS_DA_WNR*/ ? Write : Read;
+#else
+  return Unknown;
+#endif
+}
+
+bool SignalContext::IsTrueFaultingAddress() const {
+  auto si = static_cast<const siginfo_t *>(siginfo);
+  // "Real" SIGSEGV codes (e.g., SEGV_MAPERR, SEGV_MAPERR) are non-zero.
+  return si->si_signo == SIGSEGV && si->si_code != 0;
+}
+
+#if defined(__aarch64__) && defined(arm_thread_state64_get_sp)
+  #define AARCH64_GET_REG(r) \
+    (uptr)ptrauth_strip(     \
+        (void *)arm_thread_state64_get_##r(ucontext->uc_mcontext->__ss), 0)
+#else
+  #define AARCH64_GET_REG(r) (uptr)ucontext->uc_mcontext->__ss.__##r
+#endif
+
+static void GetPcSpBp(void *context, uptr *pc, uptr *sp, uptr *bp) {
+  ucontext_t *ucontext = (ucontext_t*)context;
+# if defined(__aarch64__)
+  *pc = AARCH64_GET_REG(pc);
+  *bp = AARCH64_GET_REG(fp);
+  *sp = AARCH64_GET_REG(sp);
+# elif defined(__x86_64__)
+  *pc = ucontext->uc_mcontext->__ss.__rip;
+  *bp = ucontext->uc_mcontext->__ss.__rbp;
+  *sp = ucontext->uc_mcontext->__ss.__rsp;
+# elif defined(__arm__)
+  *pc = ucontext->uc_mcontext->__ss.__pc;
+  *bp = ucontext->uc_mcontext->__ss.__r[7];
+  *sp = ucontext->uc_mcontext->__ss.__sp;
+# elif defined(__i386__)
+  *pc = ucontext->uc_mcontext->__ss.__eip;
+  *bp = ucontext->uc_mcontext->__ss.__ebp;
+  *sp = ucontext->uc_mcontext->__ss.__esp;
+# else
+# error "Unknown architecture"
+# endif
+}
+
+void SignalContext::InitPcSpBp() {
+  addr = (uptr)ptrauth_strip((void *)addr, 0);
+  GetPcSpBp(context, &pc, &sp, &bp);
+}
+
+// ASan/TSan use mmap in a way that creates “deallocation gaps” which triggers
+// EXC_GUARD exceptions on macOS 10.15+ (XNU 19.0+).
+static void DisableMmapExcGuardExceptions() {
+  using task_exc_guard_behavior_t = uint32_t;
+  using task_set_exc_guard_behavior_t =
+      kern_return_t(task_t task, task_exc_guard_behavior_t behavior);
+  auto *set_behavior = (task_set_exc_guard_behavior_t *)dlsym(
+      RTLD_DEFAULT, "task_set_exc_guard_behavior");
+  if (set_behavior == nullptr) return;
+  const task_exc_guard_behavior_t task_exc_guard_none = 0;
+  set_behavior(mach_task_self(), task_exc_guard_none);
+}
+
+static void VerifyInterceptorsWorking();
+static void StripEnv();
+
+void InitializePlatformEarly() {
+  // Only use xnu_fast_mmap when on x86_64 and the kernel supports it.
+  use_xnu_fast_mmap =
+#if defined(__x86_64__)
+      GetDarwinKernelVersion() >= DarwinKernelVersion(17, 5);
+#else
+      false;
+#endif
+  if (GetDarwinKernelVersion() >= DarwinKernelVersion(19, 0))
+    DisableMmapExcGuardExceptions();
+
+#  if !SANITIZER_GO
+  MonotonicNanoTime();  // Call to initialize mach_timebase_info
+  VerifyInterceptorsWorking();
+  StripEnv();
+#  endif
+}
+
+#if !SANITIZER_GO
+static const char kDyldInsertLibraries[] = "DYLD_INSERT_LIBRARIES";
+LowLevelAllocator allocator_for_env;
+
+static bool ShouldCheckInterceptors() {
+  // Restrict "interceptors working?" check to ASan and TSan.
+  const char *sanitizer_names[] = {"AddressSanitizer", "ThreadSanitizer"};
+  size_t count = sizeof(sanitizer_names) / sizeof(sanitizer_names[0]);
+  for (size_t i = 0; i < count; i++) {
+    if (internal_strcmp(sanitizer_names[i], SanitizerToolName) == 0)
+      return true;
+  }
+  return false;
+}
+
+static void VerifyInterceptorsWorking() {
+  if (!common_flags()->verify_interceptors || !ShouldCheckInterceptors())
+    return;
+
+  // Verify that interceptors really work.  We'll use dlsym to locate
+  // "puts", if interceptors are working, it should really point to
+  // "wrap_puts" within our own dylib.
+  Dl_info info_puts, info_runtime;
+  RAW_CHECK(dladdr(dlsym(RTLD_DEFAULT, "puts"), &info_puts));
+  RAW_CHECK(dladdr((void *)__sanitizer_report_error_summary, &info_runtime));
+  if (internal_strcmp(info_puts.dli_fname, info_runtime.dli_fname) != 0) {
+    Report(
+        "ERROR: Interceptors are not working. This may be because %s is "
+        "loaded too late (e.g. via dlopen). Please launch the executable "
+        "with:\n%s=%s\n",
+        SanitizerToolName, kDyldInsertLibraries, info_runtime.dli_fname);
+    RAW_CHECK("interceptors not installed" && 0);
+  }
+}
+
+// Change the value of the env var |name|, leaking the original value.
+// If |name_value| is NULL, the variable is deleted from the environment,
+// otherwise the corresponding "NAME=value" string is replaced with
+// |name_value|.
+static void LeakyResetEnv(const char *name, const char *name_value) {
+  char **env = GetEnviron();
+  uptr name_len = internal_strlen(name);
+  while (*env != 0) {
+    uptr len = internal_strlen(*env);
+    if (len > name_len) {
+      const char *p = *env;
+      if (!internal_memcmp(p, name, name_len) && p[name_len] == '=') {
+        // Match.
+        if (name_value) {
+          // Replace the old value with the new one.
+          *env = const_cast<char*>(name_value);
+        } else {
+          // Shift the subsequent pointers back.
+          char **del = env;
+          do {
+            del[0] = del[1];
+          } while (*del++);
+        }
+      }
+    }
+    env++;
+  }
+}
+
+static void StripEnv() {
+  if (!common_flags()->strip_env)
+    return;
+
+  char *dyld_insert_libraries =
+      const_cast<char *>(GetEnv(kDyldInsertLibraries));
+  if (!dyld_insert_libraries)
+    return;
+
+  Dl_info info;
+  RAW_CHECK(dladdr((void *)__sanitizer_report_error_summary, &info));
+  const char *dylib_name = StripModuleName(info.dli_fname);
+  bool lib_is_in_env = internal_strstr(dyld_insert_libraries, dylib_name);
+  if (!lib_is_in_env)
+    return;
+
+  // DYLD_INSERT_LIBRARIES is set and contains the runtime library. Let's remove
+  // the dylib from the environment variable, because interceptors are installed
+  // and we don't want our children to inherit the variable.
+
+  uptr old_env_len = internal_strlen(dyld_insert_libraries);
+  uptr dylib_name_len = internal_strlen(dylib_name);
+  uptr env_name_len = internal_strlen(kDyldInsertLibraries);
+  // Allocate memory to hold the previous env var name, its value, the '='
+  // sign and the '\0' char.
+  char *new_env = (char*)allocator_for_env.Allocate(
+      old_env_len + 2 + env_name_len);
+  RAW_CHECK(new_env);
+  internal_memset(new_env, '\0', old_env_len + 2 + env_name_len);
+  internal_strncpy(new_env, kDyldInsertLibraries, env_name_len);
+  new_env[env_name_len] = '=';
+  char *new_env_pos = new_env + env_name_len + 1;
+
+  // Iterate over colon-separated pieces of |dyld_insert_libraries|.
+  char *piece_start = dyld_insert_libraries;
+  char *piece_end = NULL;
+  char *old_env_end = dyld_insert_libraries + old_env_len;
+  do {
+    if (piece_start[0] == ':') piece_start++;
+    piece_end = internal_strchr(piece_start, ':');
+    if (!piece_end) piece_end = dyld_insert_libraries + old_env_len;
+    if ((uptr)(piece_start - dyld_insert_libraries) > old_env_len) break;
+    uptr piece_len = piece_end - piece_start;
+
+    char *filename_start =
+        (char *)internal_memrchr(piece_start, '/', piece_len);
+    uptr filename_len = piece_len;
+    if (filename_start) {
+      filename_start += 1;
+      filename_len = piece_len - (filename_start - piece_start);
+    } else {
+      filename_start = piece_start;
+    }
+
+    // If the current piece isn't the runtime library name,
+    // append it to new_env.
+    if ((dylib_name_len != filename_len) ||
+        (internal_memcmp(filename_start, dylib_name, dylib_name_len) != 0)) {
+      if (new_env_pos != new_env + env_name_len + 1) {
+        new_env_pos[0] = ':';
+        new_env_pos++;
+      }
+      internal_strncpy(new_env_pos, piece_start, piece_len);
+      new_env_pos += piece_len;
+    }
+    // Move on to the next piece.
+    piece_start = piece_end;
+  } while (piece_start < old_env_end);
+
+  // Can't use setenv() here, because it requires the allocator to be
+  // initialized.
+  // FIXME: instead of filtering DYLD_INSERT_LIBRARIES here, do it in
+  // a separate function called after InitializeAllocator().
+  if (new_env_pos == new_env + env_name_len + 1) new_env = NULL;
+  LeakyResetEnv(kDyldInsertLibraries, new_env);
+}
+#endif  // SANITIZER_GO
+
+char **GetArgv() {
+  return *_NSGetArgv();
+}
+
+#if SANITIZER_IOS && !SANITIZER_IOSSIM
+// The task_vm_info struct is normally provided by the macOS SDK, but we need
+// fields only available in 10.12+. Declare the struct manually to be able to
+// build against older SDKs.
+struct __sanitizer_task_vm_info {
+  mach_vm_size_t virtual_size;
+  integer_t region_count;
+  integer_t page_size;
+  mach_vm_size_t resident_size;
+  mach_vm_size_t resident_size_peak;
+  mach_vm_size_t device;
+  mach_vm_size_t device_peak;
+  mach_vm_size_t internal;
+  mach_vm_size_t internal_peak;
+  mach_vm_size_t external;
+  mach_vm_size_t external_peak;
+  mach_vm_size_t reusable;
+  mach_vm_size_t reusable_peak;
+  mach_vm_size_t purgeable_volatile_pmap;
+  mach_vm_size_t purgeable_volatile_resident;
+  mach_vm_size_t purgeable_volatile_virtual;
+  mach_vm_size_t compressed;
+  mach_vm_size_t compressed_peak;
+  mach_vm_size_t compressed_lifetime;
+  mach_vm_size_t phys_footprint;
+  mach_vm_address_t min_address;
+  mach_vm_address_t max_address;
+};
+#define __SANITIZER_TASK_VM_INFO_COUNT ((mach_msg_type_number_t) \
+    (sizeof(__sanitizer_task_vm_info) / sizeof(natural_t)))
+
+static uptr GetTaskInfoMaxAddress() {
+  __sanitizer_task_vm_info vm_info = {} /* zero initialize */;
+  mach_msg_type_number_t count = __SANITIZER_TASK_VM_INFO_COUNT;
+  int err = task_info(mach_task_self(), TASK_VM_INFO, (int *)&vm_info, &count);
+  return err ? 0 : vm_info.max_address;
+}
+
+uptr GetMaxUserVirtualAddress() {
+  static uptr max_vm = GetTaskInfoMaxAddress();
+  if (max_vm != 0) {
+    const uptr ret_value = max_vm - 1;
+    CHECK_LE(ret_value, SANITIZER_MMAP_RANGE_SIZE);
+    return ret_value;
+  }
+
+  // xnu cannot provide vm address limit
+# if SANITIZER_WORDSIZE == 32
+  constexpr uptr fallback_max_vm = 0xffe00000 - 1;
+# else
+  constexpr uptr fallback_max_vm = 0x200000000 - 1;
+# endif
+  static_assert(fallback_max_vm <= SANITIZER_MMAP_RANGE_SIZE,
+                "Max virtual address must be less than mmap range size.");
+  return fallback_max_vm;
+}
+
+#else // !SANITIZER_IOS
+
+uptr GetMaxUserVirtualAddress() {
+# if SANITIZER_WORDSIZE == 64
+  constexpr uptr max_vm = (1ULL << 47) - 1;  // 0x00007fffffffffffUL;
+# else // SANITIZER_WORDSIZE == 32
+  static_assert(SANITIZER_WORDSIZE == 32, "Wrong wordsize");
+  constexpr uptr max_vm = (1ULL << 32) - 1;  // 0xffffffff;
+# endif
+  static_assert(max_vm <= SANITIZER_MMAP_RANGE_SIZE,
+                "Max virtual address must be less than mmap range size.");
+  return max_vm;
+}
+#endif
+
+uptr GetMaxVirtualAddress() {
+  return GetMaxUserVirtualAddress();
+}
+
+uptr MapDynamicShadow(uptr shadow_size_bytes, uptr shadow_scale,
+                      uptr min_shadow_base_alignment, uptr &high_mem_end) {
+  const uptr granularity = GetMmapGranularity();
+  const uptr alignment =
+      Max<uptr>(granularity << shadow_scale, 1ULL << min_shadow_base_alignment);
+  const uptr left_padding =
+      Max<uptr>(granularity, 1ULL << min_shadow_base_alignment);
+
+  uptr space_size = shadow_size_bytes + left_padding;
+
+  uptr largest_gap_found = 0;
+  uptr max_occupied_addr = 0;
+  VReport(2, "FindDynamicShadowStart, space_size = %p\n", (void *)space_size);
+  uptr shadow_start =
+      FindAvailableMemoryRange(space_size, alignment, granularity,
+                               &largest_gap_found, &max_occupied_addr);
+  // If the shadow doesn't fit, restrict the address space to make it fit.
+  if (shadow_start == 0) {
+    VReport(
+        2,
+        "Shadow doesn't fit, largest_gap_found = %p, max_occupied_addr = %p\n",
+        (void *)largest_gap_found, (void *)max_occupied_addr);
+    uptr new_max_vm = RoundDownTo(largest_gap_found << shadow_scale, alignment);
+    if (new_max_vm < max_occupied_addr) {
+      Report("Unable to find a memory range for dynamic shadow.\n");
+      Report(
+          "space_size = %p, largest_gap_found = %p, max_occupied_addr = %p, "
+          "new_max_vm = %p\n",
+          (void *)space_size, (void *)largest_gap_found,
+          (void *)max_occupied_addr, (void *)new_max_vm);
+      CHECK(0 && "cannot place shadow");
+    }
+    RestrictMemoryToMaxAddress(new_max_vm);
+    high_mem_end = new_max_vm - 1;
+    space_size = (high_mem_end >> shadow_scale) + left_padding;
+    VReport(2, "FindDynamicShadowStart, space_size = %p\n", (void *)space_size);
+    shadow_start = FindAvailableMemoryRange(space_size, alignment, granularity,
+                                            nullptr, nullptr);
+    if (shadow_start == 0) {
+      Report("Unable to find a memory range after restricting VM.\n");
+      CHECK(0 && "cannot place shadow after restricting vm");
+    }
+  }
+  CHECK_NE((uptr)0, shadow_start);
+  CHECK(IsAligned(shadow_start, alignment));
+  return shadow_start;
+}
+
+uptr MapDynamicShadowAndAliases(uptr shadow_size, uptr alias_size,
+                                uptr num_aliases, uptr ring_buffer_size) {
+  CHECK(false && "HWASan aliasing is unimplemented on Mac");
+  return 0;
+}
+
+uptr FindAvailableMemoryRange(uptr size, uptr alignment, uptr left_padding,
+                              uptr *largest_gap_found,
+                              uptr *max_occupied_addr) {
+  typedef vm_region_submap_short_info_data_64_t RegionInfo;
+  enum { kRegionInfoSize = VM_REGION_SUBMAP_SHORT_INFO_COUNT_64 };
+  // Start searching for available memory region past PAGEZERO, which is
+  // 4KB on 32-bit and 4GB on 64-bit.
+  mach_vm_address_t start_address =
+    (SANITIZER_WORDSIZE == 32) ? 0x000000001000 : 0x000100000000;
+
+  const mach_vm_address_t max_vm_address = GetMaxVirtualAddress() + 1;
+  mach_vm_address_t address = start_address;
+  mach_vm_address_t free_begin = start_address;
+  kern_return_t kr = KERN_SUCCESS;
+  if (largest_gap_found) *largest_gap_found = 0;
+  if (max_occupied_addr) *max_occupied_addr = 0;
+  while (kr == KERN_SUCCESS) {
+    mach_vm_size_t vmsize = 0;
+    natural_t depth = 0;
+    RegionInfo vminfo;
+    mach_msg_type_number_t count = kRegionInfoSize;
+    kr = mach_vm_region_recurse(mach_task_self(), &address, &vmsize, &depth,
+                                (vm_region_info_t)&vminfo, &count);
+    if (kr == KERN_INVALID_ADDRESS) {
+      // No more regions beyond "address", consider the gap at the end of VM.
+      address = max_vm_address;
+      vmsize = 0;
+    } else {
+      if (max_occupied_addr) *max_occupied_addr = address + vmsize;
+    }
+    if (free_begin != address) {
+      // We found a free region [free_begin..address-1].
+      uptr gap_start = RoundUpTo((uptr)free_begin + left_padding, alignment);
+      uptr gap_end = RoundDownTo((uptr)Min(address, max_vm_address), alignment);
+      uptr gap_size = gap_end > gap_start ? gap_end - gap_start : 0;
+      if (size < gap_size) {
+        return gap_start;
+      }
+
+      if (largest_gap_found && *largest_gap_found < gap_size) {
+        *largest_gap_found = gap_size;
+      }
+    }
+    // Move to the next region.
+    address += vmsize;
+    free_begin = address;
+  }
+
+  // We looked at all free regions and could not find one large enough.
+  return 0;
+}
+
+// FIXME implement on this platform.
+void GetMemoryProfile(fill_profile_f cb, uptr *stats) {}
+
+void SignalContext::DumpAllRegisters(void *context) {
+  Report("Register values:\n");
+
+  ucontext_t *ucontext = (ucontext_t*)context;
+# define DUMPREG64(r) \
+    Printf("%s = 0x%016llx  ", #r, ucontext->uc_mcontext->__ss.__ ## r);
+# define DUMPREGA64(r) \
+    Printf("   %s = 0x%016lx  ", #r, AARCH64_GET_REG(r));
+# define DUMPREG32(r) \
+    Printf("%s = 0x%08x  ", #r, ucontext->uc_mcontext->__ss.__ ## r);
+# define DUMPREG_(r)   Printf(" "); DUMPREG(r);
+# define DUMPREG__(r)  Printf("  "); DUMPREG(r);
+# define DUMPREG___(r) Printf("   "); DUMPREG(r);
+
+# if defined(__x86_64__)
+#  define DUMPREG(r) DUMPREG64(r)
+  DUMPREG(rax); DUMPREG(rbx); DUMPREG(rcx); DUMPREG(rdx); Printf("\n");
+  DUMPREG(rdi); DUMPREG(rsi); DUMPREG(rbp); DUMPREG(rsp); Printf("\n");
+  DUMPREG_(r8); DUMPREG_(r9); DUMPREG(r10); DUMPREG(r11); Printf("\n");
+  DUMPREG(r12); DUMPREG(r13); DUMPREG(r14); DUMPREG(r15); Printf("\n");
+# elif defined(__i386__)
+#  define DUMPREG(r) DUMPREG32(r)
+  DUMPREG(eax); DUMPREG(ebx); DUMPREG(ecx); DUMPREG(edx); Printf("\n");
+  DUMPREG(edi); DUMPREG(esi); DUMPREG(ebp); DUMPREG(esp); Printf("\n");
+# elif defined(__aarch64__)
+#  define DUMPREG(r) DUMPREG64(r)
+  DUMPREG_(x[0]); DUMPREG_(x[1]); DUMPREG_(x[2]); DUMPREG_(x[3]); Printf("\n");
+  DUMPREG_(x[4]); DUMPREG_(x[5]); DUMPREG_(x[6]); DUMPREG_(x[7]); Printf("\n");
+  DUMPREG_(x[8]); DUMPREG_(x[9]); DUMPREG(x[10]); DUMPREG(x[11]); Printf("\n");
+  DUMPREG(x[12]); DUMPREG(x[13]); DUMPREG(x[14]); DUMPREG(x[15]); Printf("\n");
+  DUMPREG(x[16]); DUMPREG(x[17]); DUMPREG(x[18]); DUMPREG(x[19]); Printf("\n");
+  DUMPREG(x[20]); DUMPREG(x[21]); DUMPREG(x[22]); DUMPREG(x[23]); Printf("\n");
+  DUMPREG(x[24]); DUMPREG(x[25]); DUMPREG(x[26]); DUMPREG(x[27]); Printf("\n");
+  DUMPREG(x[28]); DUMPREGA64(fp); DUMPREGA64(lr); DUMPREGA64(sp); Printf("\n");
+# elif defined(__arm__)
+#  define DUMPREG(r) DUMPREG32(r)
+  DUMPREG_(r[0]); DUMPREG_(r[1]); DUMPREG_(r[2]); DUMPREG_(r[3]); Printf("\n");
+  DUMPREG_(r[4]); DUMPREG_(r[5]); DUMPREG_(r[6]); DUMPREG_(r[7]); Printf("\n");
+  DUMPREG_(r[8]); DUMPREG_(r[9]); DUMPREG(r[10]); DUMPREG(r[11]); Printf("\n");
+  DUMPREG(r[12]); DUMPREG___(sp); DUMPREG___(lr); DUMPREG___(pc); Printf("\n");
+# else
+# error "Unknown architecture"
+# endif
+
+# undef DUMPREG64
+# undef DUMPREG32
+# undef DUMPREG_
+# undef DUMPREG__
+# undef DUMPREG___
+# undef DUMPREG
+}
+
+static inline bool CompareBaseAddress(const LoadedModule &a,
+                                      const LoadedModule &b) {
+  return a.base_address() < b.base_address();
+}
+
+void FormatUUID(char *out, uptr size, const u8 *uuid) {
+  internal_snprintf(out, size,
+                    "<%02X%02X%02X%02X-%02X%02X-%02X%02X-%02X%02X-"
+                    "%02X%02X%02X%02X%02X%02X>",
+                    uuid[0], uuid[1], uuid[2], uuid[3], uuid[4], uuid[5],
+                    uuid[6], uuid[7], uuid[8], uuid[9], uuid[10], uuid[11],
+                    uuid[12], uuid[13], uuid[14], uuid[15]);
+}
+
+void DumpProcessMap() {
+  Printf("Process module map:\n");
+  MemoryMappingLayout memory_mapping(false);
+  InternalMmapVector<LoadedModule> modules;
+  modules.reserve(128);
+  memory_mapping.DumpListOfModules(&modules);
+  Sort(modules.data(), modules.size(), CompareBaseAddress);
+  for (uptr i = 0; i < modules.size(); ++i) {
+    char uuid_str[128];
+    FormatUUID(uuid_str, sizeof(uuid_str), modules[i].uuid());
+    Printf("0x%zx-0x%zx %s (%s) %s\n", modules[i].base_address(),
+           modules[i].max_address(), modules[i].full_name(),
+           ModuleArchToString(modules[i].arch()), uuid_str);
+  }
+  Printf("End of module map.\n");
+}
+
+void CheckNoDeepBind(const char *filename, int flag) {
+  // Do nothing.
+}
+
+bool GetRandom(void *buffer, uptr length, bool blocking) {
+  if (!buffer || !length || length > 256)
+    return false;
+  // arc4random never fails.
+  REAL(arc4random_buf)(buffer, length);
+  return true;
+}
+
+u32 GetNumberOfCPUs() {
+  return (u32)sysconf(_SC_NPROCESSORS_ONLN);
+}
+
+void InitializePlatformCommonFlags(CommonFlags *cf) {}
+
+// Pthread introspection hook
+//
+// * GCD worker threads are created without a call to pthread_create(), but we
+//   still need to register these threads (with ThreadCreate/Start()).
+// * We use the "pthread introspection hook" below to observe the creation of
+//   such threads.
+// * GCD worker threads don't have parent threads and the CREATE event is
+//   delivered in the context of the thread itself.  CREATE events for regular
+//   threads, are delivered on the parent.  We use this to tell apart which
+//   threads are GCD workers with `thread == pthread_self()`.
+//
+static pthread_introspection_hook_t prev_pthread_introspection_hook;
+static ThreadEventCallbacks thread_event_callbacks;
+
+static void sanitizer_pthread_introspection_hook(unsigned int event,
+                                                 pthread_t thread, void *addr,
+                                                 size_t size) {
+  // create -> start -> terminate -> destroy
+  // * create/destroy are usually (not guaranteed) delivered on the parent and
+  //   track resource allocation/reclamation
+  // * start/terminate are guaranteed to be delivered in the context of the
+  //   thread and give hooks into "just after (before) thread starts (stops)
+  //   executing"
+  DCHECK(event >= PTHREAD_INTROSPECTION_THREAD_CREATE &&
+         event <= PTHREAD_INTROSPECTION_THREAD_DESTROY);
+
+  if (event == PTHREAD_INTROSPECTION_THREAD_CREATE) {
+    bool gcd_worker = (thread == pthread_self());
+    if (thread_event_callbacks.create)
+      thread_event_callbacks.create((uptr)thread, gcd_worker);
+  } else if (event == PTHREAD_INTROSPECTION_THREAD_START) {
+    CHECK_EQ(thread, pthread_self());
+    if (thread_event_callbacks.start)
+      thread_event_callbacks.start((uptr)thread);
+  }
+
+  if (prev_pthread_introspection_hook)
+    prev_pthread_introspection_hook(event, thread, addr, size);
+
+  if (event == PTHREAD_INTROSPECTION_THREAD_TERMINATE) {
+    CHECK_EQ(thread, pthread_self());
+    if (thread_event_callbacks.terminate)
+      thread_event_callbacks.terminate((uptr)thread);
+  } else if (event == PTHREAD_INTROSPECTION_THREAD_DESTROY) {
+    if (thread_event_callbacks.destroy)
+      thread_event_callbacks.destroy((uptr)thread);
+  }
+}
+
+void InstallPthreadIntrospectionHook(const ThreadEventCallbacks &callbacks) {
+  thread_event_callbacks = callbacks;
+  prev_pthread_introspection_hook =
+      pthread_introspection_hook_install(&sanitizer_pthread_introspection_hook);
+}
+
+}  // namespace __sanitizer
+
+#endif  // SANITIZER_APPLE