libsanitizer: add hwasan.

Introduce the libhwasan library from LLVM sources.

34 files changed, 4575 insertions, 1 deletions

diff --git a/libsanitizer/MERGE b/libsanitizer/MERGE
index 2df9b4637b1..0fb64a9567c 100644
--- a/libsanitizer/MERGE
+++ b/libsanitizer/MERGE
@@ -1,4 +1,4 @@
-a28a466210199559d38251c11f30515cc83eadd6
+6e7dd1e3e1170080b76b5dcc5716bdd974343233
 
 The first line of this file holds the git revision number of the
 last merge done from the master library sources.
diff --git a/libsanitizer/README.gcc b/libsanitizer/README.gcc
index fdb0ec5ba09..07defc5b6d8 100644
--- a/libsanitizer/README.gcc
+++ b/libsanitizer/README.gcc
@@ -11,6 +11,7 @@ https://github.com/llvm/llvm-project in the following directories:
   compiler-rt/lib/tsan
   compiler-rt/lib/lsan
   compiler-rt/lib/ubsan
+  compiler-rt/lib/hwasan
 
 Trivial and urgent fixes (portability, build fixes, etc.) may go directly to the
 GCC tree.  All non-trivial changes, functionality improvements, etc. should go
diff --git a/libsanitizer/hwasan/hwasan.cpp b/libsanitizer/hwasan/hwasan.cpp
new file mode 100644
index 00000000000..c5322110cb6
--- /dev/null
+++ b/libsanitizer/hwasan/hwasan.cpp
@@ -0,0 +1,522 @@
+//===-- hwasan.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 a part of HWAddressSanitizer.
+//
+// HWAddressSanitizer runtime.
+//===----------------------------------------------------------------------===//
+
+#include "hwasan.h"
+
+#include "hwasan_checks.h"
+#include "hwasan_dynamic_shadow.h"
+#include "hwasan_globals.h"
+#include "hwasan_poisoning.h"
+#include "hwasan_report.h"
+#include "hwasan_thread.h"
+#include "hwasan_thread_list.h"
+#include "sanitizer_common/sanitizer_atomic.h"
+#include "sanitizer_common/sanitizer_common.h"
+#include "sanitizer_common/sanitizer_flag_parser.h"
+#include "sanitizer_common/sanitizer_flags.h"
+#include "sanitizer_common/sanitizer_libc.h"
+#include "sanitizer_common/sanitizer_procmaps.h"
+#include "sanitizer_common/sanitizer_stackdepot.h"
+#include "sanitizer_common/sanitizer_stacktrace.h"
+#include "sanitizer_common/sanitizer_symbolizer.h"
+#include "ubsan/ubsan_flags.h"
+#include "ubsan/ubsan_init.h"
+
+// ACHTUNG! No system header includes in this file.
+
+using namespace __sanitizer;
+
+namespace __hwasan {
+
+static Flags hwasan_flags;
+
+Flags *flags() {
+  return &hwasan_flags;
+}
+
+int hwasan_inited = 0;
+int hwasan_instrumentation_inited = 0;
+bool hwasan_init_is_running;
+
+int hwasan_report_count = 0;
+
+void Flags::SetDefaults() {
+#define HWASAN_FLAG(Type, Name, DefaultValue, Description) Name = DefaultValue;
+#include "hwasan_flags.inc"
+#undef HWASAN_FLAG
+}
+
+static void RegisterHwasanFlags(FlagParser *parser, Flags *f) {
+#define HWASAN_FLAG(Type, Name, DefaultValue, Description) \
+  RegisterFlag(parser, #Name, Description, &f->Name);
+#include "hwasan_flags.inc"
+#undef HWASAN_FLAG
+}
+
+static void InitializeFlags() {
+  SetCommonFlagsDefaults();
+  {
+    CommonFlags cf;
+    cf.CopyFrom(*common_flags());
+    cf.external_symbolizer_path = GetEnv("HWASAN_SYMBOLIZER_PATH");
+    cf.malloc_context_size = 20;
+    cf.handle_ioctl = true;
+    // FIXME: test and enable.
+    cf.check_printf = false;
+    cf.intercept_tls_get_addr = true;
+    cf.exitcode = 99;
+    // 8 shadow pages ~512kB, small enough to cover common stack sizes.
+    cf.clear_shadow_mmap_threshold = 4096 * (SANITIZER_ANDROID ? 2 : 8);
+    // Sigtrap is used in error reporting.
+    cf.handle_sigtrap = kHandleSignalExclusive;
+
+#if SANITIZER_ANDROID
+    // Let platform handle other signals. It is better at reporting them then we
+    // are.
+    cf.handle_segv = kHandleSignalNo;
+    cf.handle_sigbus = kHandleSignalNo;
+    cf.handle_abort = kHandleSignalNo;
+    cf.handle_sigill = kHandleSignalNo;
+    cf.handle_sigfpe = kHandleSignalNo;
+#endif
+    OverrideCommonFlags(cf);
+  }
+
+  Flags *f = flags();
+  f->SetDefaults();
+
+  FlagParser parser;
+  RegisterHwasanFlags(&parser, f);
+  RegisterCommonFlags(&parser);
+
+#if HWASAN_CONTAINS_UBSAN
+  __ubsan::Flags *uf = __ubsan::flags();
+  uf->SetDefaults();
+
+  FlagParser ubsan_parser;
+  __ubsan::RegisterUbsanFlags(&ubsan_parser, uf);
+  RegisterCommonFlags(&ubsan_parser);
+#endif
+
+  // Override from user-specified string.
+  if (__hwasan_default_options)
+    parser.ParseString(__hwasan_default_options());
+#if HWASAN_CONTAINS_UBSAN
+  const char *ubsan_default_options = __ubsan_default_options();
+  ubsan_parser.ParseString(ubsan_default_options);
+#endif
+
+  parser.ParseStringFromEnv("HWASAN_OPTIONS");
+#if HWASAN_CONTAINS_UBSAN
+  ubsan_parser.ParseStringFromEnv("UBSAN_OPTIONS");
+#endif
+
+  InitializeCommonFlags();
+
+  if (Verbosity()) ReportUnrecognizedFlags();
+
+  if (common_flags()->help) parser.PrintFlagDescriptions();
+}
+
+static void HWAsanCheckFailed(const char *file, int line, const char *cond,
+                              u64 v1, u64 v2) {
+  Report("HWAddressSanitizer CHECK failed: %s:%d \"%s\" (0x%zx, 0x%zx)\n", file,
+         line, cond, (uptr)v1, (uptr)v2);
+  PRINT_CURRENT_STACK_CHECK();
+  Die();
+}
+
+static constexpr uptr kMemoryUsageBufferSize = 4096;
+
+static void HwasanFormatMemoryUsage(InternalScopedString &s) {
+  HwasanThreadList &thread_list = hwasanThreadList();
+  auto thread_stats = thread_list.GetThreadStats();
+  auto *sds = StackDepotGetStats();
+  AllocatorStatCounters asc;
+  GetAllocatorStats(asc);
+  s.append(
+      "HWASAN pid: %d rss: %zd threads: %zd stacks: %zd"
+      " thr_aux: %zd stack_depot: %zd uniq_stacks: %zd"
+      " heap: %zd",
+      internal_getpid(), GetRSS(), thread_stats.n_live_threads,
+      thread_stats.total_stack_size,
+      thread_stats.n_live_threads * thread_list.MemoryUsedPerThread(),
+      sds->allocated, sds->n_uniq_ids, asc[AllocatorStatMapped]);
+}
+
+#if SANITIZER_ANDROID
+static char *memory_usage_buffer = nullptr;
+
+static void InitMemoryUsage() {
+  memory_usage_buffer =
+      (char *)MmapOrDie(kMemoryUsageBufferSize, "memory usage string");
+  CHECK(memory_usage_buffer);
+  memory_usage_buffer[0] = '\0';
+  DecorateMapping((uptr)memory_usage_buffer, kMemoryUsageBufferSize,
+                  memory_usage_buffer);
+}
+
+void UpdateMemoryUsage() {
+  if (!flags()->export_memory_stats)
+    return;
+  if (!memory_usage_buffer)
+    InitMemoryUsage();
+  InternalScopedString s(kMemoryUsageBufferSize);
+  HwasanFormatMemoryUsage(s);
+  internal_strncpy(memory_usage_buffer, s.data(), kMemoryUsageBufferSize - 1);
+  memory_usage_buffer[kMemoryUsageBufferSize - 1] = '\0';
+}
+#else
+void UpdateMemoryUsage() {}
+#endif
+
+} // namespace __hwasan
+
+using namespace __hwasan;
+
+void __sanitizer::BufferedStackTrace::UnwindImpl(
+    uptr pc, uptr bp, void *context, bool request_fast, u32 max_depth) {
+  Thread *t = GetCurrentThread();
+  if (!t) {
+    // The thread is still being created, or has already been destroyed.
+    size = 0;
+    return;
+  }
+  Unwind(max_depth, pc, bp, context, t->stack_top(), t->stack_bottom(),
+         request_fast);
+}
+
+static bool InitializeSingleGlobal(const hwasan_global &global) {
+  uptr full_granule_size = RoundDownTo(global.size(), 16);
+  TagMemoryAligned(global.addr(), full_granule_size, global.tag());
+  if (global.size() % 16)
+    TagMemoryAligned(global.addr() + full_granule_size, 16, global.size() % 16);
+  return false;
+}
+
+static void InitLoadedGlobals() {
+  dl_iterate_phdr(
+      [](dl_phdr_info *info, size_t /* size */, void * /* data */) -> int {
+        for (const hwasan_global &global : HwasanGlobalsFor(
+                 info->dlpi_addr, info->dlpi_phdr, info->dlpi_phnum))
+          InitializeSingleGlobal(global);
+        return 0;
+      },
+      nullptr);
+}
+
+// Prepare to run instrumented code on the main thread.
+static void InitInstrumentation() {
+  if (hwasan_instrumentation_inited) return;
+
+  InitPrctl();
+
+  if (!InitShadow()) {
+    Printf("FATAL: HWAddressSanitizer cannot mmap the shadow memory.\n");
+    DumpProcessMap();
+    Die();
+  }
+
+  InitThreads();
+  hwasanThreadList().CreateCurrentThread();
+
+  hwasan_instrumentation_inited = 1;
+}
+
+// Interface.
+
+uptr __hwasan_shadow_memory_dynamic_address;  // Global interface symbol.
+
+// This function was used by the old frame descriptor mechanism. We keep it
+// around to avoid breaking ABI.
+void __hwasan_init_frames(uptr beg, uptr end) {}
+
+void __hwasan_init_static() {
+  InitShadowGOT();
+  InitInstrumentation();
+
+  // In the non-static code path we call dl_iterate_phdr here. But at this point
+  // libc might not have been initialized enough for dl_iterate_phdr to work.
+  // Fortunately, since this is a statically linked executable we can use the
+  // linker-defined symbol __ehdr_start to find the only relevant set of phdrs.
+  extern ElfW(Ehdr) __ehdr_start;
+  for (const hwasan_global &global : HwasanGlobalsFor(
+           /* base */ 0,
+           reinterpret_cast<const ElfW(Phdr) *>(
+               reinterpret_cast<const char *>(&__ehdr_start) +
+               __ehdr_start.e_phoff),
+           __ehdr_start.e_phnum))
+    InitializeSingleGlobal(global);
+}
+
+void __hwasan_init() {
+  CHECK(!hwasan_init_is_running);
+  if (hwasan_inited) return;
+  hwasan_init_is_running = 1;
+  SanitizerToolName = "HWAddressSanitizer";
+
+  InitTlsSize();
+
+  CacheBinaryName();
+  InitializeFlags();
+
+  // Install tool-specific callbacks in sanitizer_common.
+  SetCheckFailedCallback(HWAsanCheckFailed);
+
+  __sanitizer_set_report_path(common_flags()->log_path);
+
+  AndroidTestTlsSlot();
+
+  DisableCoreDumperIfNecessary();
+
+  InitInstrumentation();
+  InitLoadedGlobals();
+
+  // Needs to be called here because flags()->random_tags might not have been
+  // initialized when InitInstrumentation() was called.
+  GetCurrentThread()->InitRandomState();
+
+  SetPrintfAndReportCallback(AppendToErrorMessageBuffer);
+  // This may call libc -> needs initialized shadow.
+  AndroidLogInit();
+
+  InitializeInterceptors();
+  InstallDeadlySignalHandlers(HwasanOnDeadlySignal);
+  InstallAtExitHandler(); // Needs __cxa_atexit interceptor.
+
+  InitializeCoverage(common_flags()->coverage, common_flags()->coverage_dir);
+
+  HwasanTSDInit();
+  HwasanTSDThreadInit();
+
+  HwasanAllocatorInit();
+
+#if HWASAN_CONTAINS_UBSAN
+  __ubsan::InitAsPlugin();
+#endif
+
+  VPrintf(1, "HWAddressSanitizer init done\n");
+
+  hwasan_init_is_running = 0;
+  hwasan_inited = 1;
+}
+
+void __hwasan_library_loaded(ElfW(Addr) base, const ElfW(Phdr) * phdr,
+                             ElfW(Half) phnum) {
+  for (const hwasan_global &global : HwasanGlobalsFor(base, phdr, phnum))
+    InitializeSingleGlobal(global);
+}
+
+void __hwasan_library_unloaded(ElfW(Addr) base, const ElfW(Phdr) * phdr,
+                               ElfW(Half) phnum) {
+  for (; phnum != 0; ++phdr, --phnum)
+    if (phdr->p_type == PT_LOAD)
+      TagMemory(base + phdr->p_vaddr, phdr->p_memsz, 0);
+}
+
+void __hwasan_print_shadow(const void *p, uptr sz) {
+  uptr ptr_raw = UntagAddr(reinterpret_cast<uptr>(p));
+  uptr shadow_first = MemToShadow(ptr_raw);
+  uptr shadow_last = MemToShadow(ptr_raw + sz - 1);
+  Printf("HWASan shadow map for %zx .. %zx (pointer tag %x)\n", ptr_raw,
+         ptr_raw + sz, GetTagFromPointer((uptr)p));
+  for (uptr s = shadow_first; s <= shadow_last; ++s)
+    Printf("  %zx: %x\n", ShadowToMem(s), *(tag_t *)s);
+}
+
+sptr __hwasan_test_shadow(const void *p, uptr sz) {
+  if (sz == 0)
+    return -1;
+  tag_t ptr_tag = GetTagFromPointer((uptr)p);
+  uptr ptr_raw = UntagAddr(reinterpret_cast<uptr>(p));
+  uptr shadow_first = MemToShadow(ptr_raw);
+  uptr shadow_last = MemToShadow(ptr_raw + sz - 1);
+  for (uptr s = shadow_first; s <= shadow_last; ++s)
+    if (*(tag_t *)s != ptr_tag) {
+      sptr offset = ShadowToMem(s) - ptr_raw;
+      return offset < 0 ? 0 : offset;
+    }
+  return -1;
+}
+
+u16 __sanitizer_unaligned_load16(const uu16 *p) {
+  return *p;
+}
+u32 __sanitizer_unaligned_load32(const uu32 *p) {
+  return *p;
+}
+u64 __sanitizer_unaligned_load64(const uu64 *p) {
+  return *p;
+}
+void __sanitizer_unaligned_store16(uu16 *p, u16 x) {
+  *p = x;
+}
+void __sanitizer_unaligned_store32(uu32 *p, u32 x) {
+  *p = x;
+}
+void __sanitizer_unaligned_store64(uu64 *p, u64 x) {
+  *p = x;
+}
+
+void __hwasan_loadN(uptr p, uptr sz) {
+  CheckAddressSized<ErrorAction::Abort, AccessType::Load>(p, sz);
+}
+void __hwasan_load1(uptr p) {
+  CheckAddress<ErrorAction::Abort, AccessType::Load, 0>(p);
+}
+void __hwasan_load2(uptr p) {
+  CheckAddress<ErrorAction::Abort, AccessType::Load, 1>(p);
+}
+void __hwasan_load4(uptr p) {
+  CheckAddress<ErrorAction::Abort, AccessType::Load, 2>(p);
+}
+void __hwasan_load8(uptr p) {
+  CheckAddress<ErrorAction::Abort, AccessType::Load, 3>(p);
+}
+void __hwasan_load16(uptr p) {
+  CheckAddress<ErrorAction::Abort, AccessType::Load, 4>(p);
+}
+
+void __hwasan_loadN_noabort(uptr p, uptr sz) {
+  CheckAddressSized<ErrorAction::Recover, AccessType::Load>(p, sz);
+}
+void __hwasan_load1_noabort(uptr p) {
+  CheckAddress<ErrorAction::Recover, AccessType::Load, 0>(p);
+}
+void __hwasan_load2_noabort(uptr p) {
+  CheckAddress<ErrorAction::Recover, AccessType::Load, 1>(p);
+}
+void __hwasan_load4_noabort(uptr p) {
+  CheckAddress<ErrorAction::Recover, AccessType::Load, 2>(p);
+}
+void __hwasan_load8_noabort(uptr p) {
+  CheckAddress<ErrorAction::Recover, AccessType::Load, 3>(p);
+}
+void __hwasan_load16_noabort(uptr p) {
+  CheckAddress<ErrorAction::Recover, AccessType::Load, 4>(p);
+}
+
+void __hwasan_storeN(uptr p, uptr sz) {
+  CheckAddressSized<ErrorAction::Abort, AccessType::Store>(p, sz);
+}
+void __hwasan_store1(uptr p) {
+  CheckAddress<ErrorAction::Abort, AccessType::Store, 0>(p);
+}
+void __hwasan_store2(uptr p) {
+  CheckAddress<ErrorAction::Abort, AccessType::Store, 1>(p);
+}
+void __hwasan_store4(uptr p) {
+  CheckAddress<ErrorAction::Abort, AccessType::Store, 2>(p);
+}
+void __hwasan_store8(uptr p) {
+  CheckAddress<ErrorAction::Abort, AccessType::Store, 3>(p);
+}
+void __hwasan_store16(uptr p) {
+  CheckAddress<ErrorAction::Abort, AccessType::Store, 4>(p);
+}
+
+void __hwasan_storeN_noabort(uptr p, uptr sz) {
+  CheckAddressSized<ErrorAction::Recover, AccessType::Store>(p, sz);
+}
+void __hwasan_store1_noabort(uptr p) {
+  CheckAddress<ErrorAction::Recover, AccessType::Store, 0>(p);
+}
+void __hwasan_store2_noabort(uptr p) {
+  CheckAddress<ErrorAction::Recover, AccessType::Store, 1>(p);
+}
+void __hwasan_store4_noabort(uptr p) {
+  CheckAddress<ErrorAction::Recover, AccessType::Store, 2>(p);
+}
+void __hwasan_store8_noabort(uptr p) {
+  CheckAddress<ErrorAction::Recover, AccessType::Store, 3>(p);
+}
+void __hwasan_store16_noabort(uptr p) {
+  CheckAddress<ErrorAction::Recover, AccessType::Store, 4>(p);
+}
+
+void __hwasan_tag_memory(uptr p, u8 tag, uptr sz) {
+  TagMemoryAligned(p, sz, tag);
+}
+
+uptr __hwasan_tag_pointer(uptr p, u8 tag) {
+  return AddTagToPointer(p, tag);
+}
+
+void __hwasan_handle_longjmp(const void *sp_dst) {
+  uptr dst = (uptr)sp_dst;
+  // HWASan does not support tagged SP.
+  CHECK(GetTagFromPointer(dst) == 0);
+
+  uptr sp = (uptr)__builtin_frame_address(0);
+  static const uptr kMaxExpectedCleanupSize = 64 << 20;  // 64M
+  if (dst < sp || dst - sp > kMaxExpectedCleanupSize) {
+    Report(
+        "WARNING: HWASan is ignoring requested __hwasan_handle_longjmp: "
+        "stack top: %p; target %p; distance: %p (%zd)\n"
+        "False positive error reports may follow\n",
+        (void *)sp, (void *)dst, dst - sp);
+    return;
+  }
+  TagMemory(sp, dst - sp, 0);
+}
+
+void __hwasan_handle_vfork(const void *sp_dst) {
+  uptr sp = (uptr)sp_dst;
+  Thread *t = GetCurrentThread();
+  CHECK(t);
+  uptr top = t->stack_top();
+  uptr bottom = t->stack_bottom();
+  if (top == 0 || bottom == 0 || sp < bottom || sp >= top) {
+    Report(
+        "WARNING: HWASan is ignoring requested __hwasan_handle_vfork: "
+        "stack top: %zx; current %zx; bottom: %zx \n"
+        "False positive error reports may follow\n",
+        top, sp, bottom);
+    return;
+  }
+  TagMemory(bottom, sp - bottom, 0);
+}
+
+extern "C" void *__hwasan_extra_spill_area() {
+  Thread *t = GetCurrentThread();
+  return &t->vfork_spill();
+}
+
+void __hwasan_print_memory_usage() {
+  InternalScopedString s(kMemoryUsageBufferSize);
+  HwasanFormatMemoryUsage(s);
+  Printf("%s\n", s.data());
+}
+
+static const u8 kFallbackTag = 0xBB;
+
+u8 __hwasan_generate_tag() {
+  Thread *t = GetCurrentThread();
+  if (!t) return kFallbackTag;
+  return t->GenerateRandomTag();
+}
+
+#if !SANITIZER_SUPPORTS_WEAK_HOOKS
+extern "C" {
+SANITIZER_INTERFACE_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE
+const char* __hwasan_default_options() { return ""; }
+}  // extern "C"
+#endif
+
+extern "C" {
+SANITIZER_INTERFACE_ATTRIBUTE
+void __sanitizer_print_stack_trace() {
+  GET_FATAL_STACK_TRACE_PC_BP(StackTrace::GetCurrentPc(), GET_CURRENT_FRAME());
+  stack.Print();
+}
+} // extern "C"
diff --git a/libsanitizer/hwasan/hwasan.h b/libsanitizer/hwasan/hwasan.h
new file mode 100644
index 00000000000..d4521efd089
--- /dev/null
+++ b/libsanitizer/hwasan/hwasan.h
@@ -0,0 +1,165 @@
+//===-- hwasan.h ------------------------------------------------*- C++ -*-===//
+//
+// 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 a part of HWAddressSanitizer.
+//
+// Private Hwasan header.
+//===----------------------------------------------------------------------===//
+
+#ifndef HWASAN_H
+#define HWASAN_H
+
+#include "sanitizer_common/sanitizer_flags.h"
+#include "sanitizer_common/sanitizer_internal_defs.h"
+#include "sanitizer_common/sanitizer_stacktrace.h"
+#include "hwasan_interface_internal.h"
+#include "hwasan_flags.h"
+#include "ubsan/ubsan_platform.h"
+
+#ifndef HWASAN_CONTAINS_UBSAN
+# define HWASAN_CONTAINS_UBSAN CAN_SANITIZE_UB
+#endif
+
+#ifndef HWASAN_WITH_INTERCEPTORS
+#define HWASAN_WITH_INTERCEPTORS 0
+#endif
+
+#ifndef HWASAN_REPLACE_OPERATORS_NEW_AND_DELETE
+#define HWASAN_REPLACE_OPERATORS_NEW_AND_DELETE HWASAN_WITH_INTERCEPTORS
+#endif
+
+typedef u8 tag_t;
+
+// TBI (Top Byte Ignore) feature of AArch64: bits [63:56] are ignored in address
+// translation and can be used to store a tag.
+const unsigned kAddressTagShift = 56;
+const uptr kAddressTagMask = 0xFFUL << kAddressTagShift;
+
+// Minimal alignment of the shadow base address. Determines the space available
+// for threads and stack histories. This is an ABI constant.
+const unsigned kShadowBaseAlignment = 32;
+
+const unsigned kRecordAddrBaseTagShift = 3;
+const unsigned kRecordFPShift = 48;
+const unsigned kRecordFPLShift = 4;
+const unsigned kRecordFPModulus = 1 << (64 - kRecordFPShift + kRecordFPLShift);
+
+static inline tag_t GetTagFromPointer(uptr p) {
+  return p >> kAddressTagShift;
+}
+
+static inline uptr UntagAddr(uptr tagged_addr) {
+  return tagged_addr & ~kAddressTagMask;
+}
+
+static inline void *UntagPtr(const void *tagged_ptr) {
+  return reinterpret_cast<void *>(
+      UntagAddr(reinterpret_cast<uptr>(tagged_ptr)));
+}
+
+static inline uptr AddTagToPointer(uptr p, tag_t tag) {
+  return (p & ~kAddressTagMask) | ((uptr)tag << kAddressTagShift);
+}
+
+namespace __hwasan {
+
+extern int hwasan_inited;
+extern bool hwasan_init_is_running;
+extern int hwasan_report_count;
+
+bool InitShadow();
+void InitPrctl();
+void InitThreads();
+void InitializeInterceptors();
+
+void HwasanAllocatorInit();
+
+void *hwasan_malloc(uptr size, StackTrace *stack);
+void *hwasan_calloc(uptr nmemb, uptr size, StackTrace *stack);
+void *hwasan_realloc(void *ptr, uptr size, StackTrace *stack);
+void *hwasan_reallocarray(void *ptr, uptr nmemb, uptr size, StackTrace *stack);
+void *hwasan_valloc(uptr size, StackTrace *stack);
+void *hwasan_pvalloc(uptr size, StackTrace *stack);
+void *hwasan_aligned_alloc(uptr alignment, uptr size, StackTrace *stack);
+void *hwasan_memalign(uptr alignment, uptr size, StackTrace *stack);
+int hwasan_posix_memalign(void **memptr, uptr alignment, uptr size,
+                        StackTrace *stack);
+void hwasan_free(void *ptr, StackTrace *stack);
+
+void InstallAtExitHandler();
+
+#define GET_MALLOC_STACK_TRACE                                            \
+  BufferedStackTrace stack;                                               \
+  if (hwasan_inited)                                                      \
+    stack.Unwind(StackTrace::GetCurrentPc(), GET_CURRENT_FRAME(),         \
+                 nullptr, common_flags()->fast_unwind_on_malloc,          \
+                 common_flags()->malloc_context_size)
+
+#define GET_FATAL_STACK_TRACE_PC_BP(pc, bp)              \
+  BufferedStackTrace stack;                              \
+  if (hwasan_inited)                                     \
+    stack.Unwind(pc, bp, nullptr, common_flags()->fast_unwind_on_fatal)
+
+#define GET_FATAL_STACK_TRACE_HERE \
+  GET_FATAL_STACK_TRACE_PC_BP(StackTrace::GetCurrentPc(), GET_CURRENT_FRAME())
+
+#define PRINT_CURRENT_STACK_CHECK() \
+  {                                 \
+    GET_FATAL_STACK_TRACE_HERE;     \
+    stack.Print();                  \
+  }
+
+void HwasanTSDInit();
+void HwasanTSDThreadInit();
+
+void HwasanOnDeadlySignal(int signo, void *info, void *context);
+
+void UpdateMemoryUsage();
+
+void AppendToErrorMessageBuffer(const char *buffer);
+
+void AndroidTestTlsSlot();
+
+}  // namespace __hwasan
+
+#define HWASAN_MALLOC_HOOK(ptr, size)       \
+  do {                                    \
+    if (&__sanitizer_malloc_hook) {       \
+      __sanitizer_malloc_hook(ptr, size); \
+    }                                     \
+    RunMallocHooks(ptr, size);            \
+  } while (false)
+#define HWASAN_FREE_HOOK(ptr)       \
+  do {                            \
+    if (&__sanitizer_free_hook) { \
+      __sanitizer_free_hook(ptr); \
+    }                             \
+    RunFreeHooks(ptr);            \
+  } while (false)
+
+#if HWASAN_WITH_INTERCEPTORS && defined(__aarch64__)
+// For both bionic and glibc __sigset_t is an unsigned long.
+typedef unsigned long __hw_sigset_t;
+// Setjmp and longjmp implementations are platform specific, and hence the
+// interception code is platform specific too.  As yet we've only implemented
+// the interception for AArch64.
+typedef unsigned long long __hw_register_buf[22];
+struct __hw_jmp_buf_struct {
+  // NOTE: The machine-dependent definition of `__sigsetjmp'
+  // assume that a `__hw_jmp_buf' begins with a `__hw_register_buf' and that
+  // `__mask_was_saved' follows it.  Do not move these members or add others
+  // before it.
+  __hw_register_buf __jmpbuf; // Calling environment.
+  int __mask_was_saved;       // Saved the signal mask?
+  __hw_sigset_t __saved_mask; // Saved signal mask.
+};
+typedef struct __hw_jmp_buf_struct __hw_jmp_buf[1];
+typedef struct __hw_jmp_buf_struct __hw_sigjmp_buf[1];
+#endif // HWASAN_WITH_INTERCEPTORS && __aarch64__
+
+#endif  // HWASAN_H
diff --git a/libsanitizer/hwasan/hwasan_allocator.cpp b/libsanitizer/hwasan/hwasan_allocator.cpp
new file mode 100644
index 00000000000..0b6b7347892
--- /dev/null
+++ b/libsanitizer/hwasan/hwasan_allocator.cpp
@@ -0,0 +1,408 @@
+//===-- hwasan_allocator.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 a part of HWAddressSanitizer.
+//
+// HWAddressSanitizer allocator.
+//===----------------------------------------------------------------------===//
+
+#include "sanitizer_common/sanitizer_atomic.h"
+#include "sanitizer_common/sanitizer_errno.h"
+#include "sanitizer_common/sanitizer_stackdepot.h"
+#include "hwasan.h"
+#include "hwasan_allocator.h"
+#include "hwasan_checks.h"
+#include "hwasan_mapping.h"
+#include "hwasan_malloc_bisect.h"
+#include "hwasan_thread.h"
+#include "hwasan_report.h"
+
+namespace __hwasan {
+
+static Allocator allocator;
+static AllocatorCache fallback_allocator_cache;
+static SpinMutex fallback_mutex;
+static atomic_uint8_t hwasan_allocator_tagging_enabled;
+
+static const tag_t kFallbackAllocTag = 0xBB;
+static const tag_t kFallbackFreeTag = 0xBC;
+
+enum RightAlignMode {
+  kRightAlignNever,
+  kRightAlignSometimes,
+  kRightAlignAlways
+};
+
+// Initialized in HwasanAllocatorInit, an never changed.
+static ALIGNED(16) u8 tail_magic[kShadowAlignment - 1];
+
+bool HwasanChunkView::IsAllocated() const {
+  return metadata_ && metadata_->alloc_context_id &&
+         metadata_->get_requested_size();
+}
+
+// Aligns the 'addr' right to the granule boundary.
+static uptr AlignRight(uptr addr, uptr requested_size) {
+  uptr tail_size = requested_size % kShadowAlignment;
+  if (!tail_size) return addr;
+  return addr + kShadowAlignment - tail_size;
+}
+
+uptr HwasanChunkView::Beg() const {
+  if (metadata_ && metadata_->right_aligned)
+    return AlignRight(block_, metadata_->get_requested_size());
+  return block_;
+}
+uptr HwasanChunkView::End() const {
+  return Beg() + UsedSize();
+}
+uptr HwasanChunkView::UsedSize() const {
+  return metadata_->get_requested_size();
+}
+u32 HwasanChunkView::GetAllocStackId() const {
+  return metadata_->alloc_context_id;
+}
+
+uptr HwasanChunkView::ActualSize() const {
+  return allocator.GetActuallyAllocatedSize(reinterpret_cast<void *>(block_));
+}
+
+bool HwasanChunkView::FromSmallHeap() const {
+  return allocator.FromPrimary(reinterpret_cast<void *>(block_));
+}
+
+void GetAllocatorStats(AllocatorStatCounters s) {
+  allocator.GetStats(s);
+}
+
+void HwasanAllocatorInit() {
+  atomic_store_relaxed(&hwasan_allocator_tagging_enabled,
+                       !flags()->disable_allocator_tagging);
+  SetAllocatorMayReturnNull(common_flags()->allocator_may_return_null);
+  allocator.Init(common_flags()->allocator_release_to_os_interval_ms);
+  for (uptr i = 0; i < sizeof(tail_magic); i++)
+    tail_magic[i] = GetCurrentThread()->GenerateRandomTag();
+}
+
+void AllocatorSwallowThreadLocalCache(AllocatorCache *cache) {
+  allocator.SwallowCache(cache);
+}
+
+static uptr TaggedSize(uptr size) {
+  if (!size) size = 1;
+  uptr new_size = RoundUpTo(size, kShadowAlignment);
+  CHECK_GE(new_size, size);
+  return new_size;
+}
+
+static void *HwasanAllocate(StackTrace *stack, uptr orig_size, uptr alignment,
+                            bool zeroise) {
+  if (orig_size > kMaxAllowedMallocSize) {
+    if (AllocatorMayReturnNull()) {
+      Report("WARNING: HWAddressSanitizer failed to allocate 0x%zx bytes\n",
+             orig_size);
+      return nullptr;
+    }
+    ReportAllocationSizeTooBig(orig_size, kMaxAllowedMallocSize, stack);
+  }
+
+  alignment = Max(alignment, kShadowAlignment);
+  uptr size = TaggedSize(orig_size);
+  Thread *t = GetCurrentThread();
+  void *allocated;
+  if (t) {
+    allocated = allocator.Allocate(t->allocator_cache(), size, alignment);
+  } else {
+    SpinMutexLock l(&fallback_mutex);
+    AllocatorCache *cache = &fallback_allocator_cache;
+    allocated = allocator.Allocate(cache, size, alignment);
+  }
+  if (UNLIKELY(!allocated)) {
+    SetAllocatorOutOfMemory();
+    if (AllocatorMayReturnNull())
+      return nullptr;
+    ReportOutOfMemory(size, stack);
+  }
+  Metadata *meta =
+      reinterpret_cast<Metadata *>(allocator.GetMetaData(allocated));
+  meta->set_requested_size(orig_size);
+  meta->alloc_context_id = StackDepotPut(*stack);
+  meta->right_aligned = false;
+  if (zeroise) {
+    internal_memset(allocated, 0, size);
+  } else if (flags()->max_malloc_fill_size > 0) {
+    uptr fill_size = Min(size, (uptr)flags()->max_malloc_fill_size);
+    internal_memset(allocated, flags()->malloc_fill_byte, fill_size);
+  }
+  if (size != orig_size) {
+    internal_memcpy(reinterpret_cast<u8 *>(allocated) + orig_size, tail_magic,
+                    size - orig_size - 1);
+  }
+
+  void *user_ptr = allocated;
+  // Tagging can only be skipped when both tag_in_malloc and tag_in_free are
+  // false. When tag_in_malloc = false and tag_in_free = true malloc needs to
+  // retag to 0.
+  if ((flags()->tag_in_malloc || flags()->tag_in_free) &&
+      atomic_load_relaxed(&hwasan_allocator_tagging_enabled)) {
+    if (flags()->tag_in_malloc && malloc_bisect(stack, orig_size)) {
+      tag_t tag = t ? t->GenerateRandomTag() : kFallbackAllocTag;
+      uptr tag_size = orig_size ? orig_size : 1;
+      uptr full_granule_size = RoundDownTo(tag_size, kShadowAlignment);
+      user_ptr =
+          (void *)TagMemoryAligned((uptr)user_ptr, full_granule_size, tag);
+      if (full_granule_size != tag_size) {
+        u8 *short_granule =
+            reinterpret_cast<u8 *>(allocated) + full_granule_size;
+        TagMemoryAligned((uptr)short_granule, kShadowAlignment,
+                         tag_size % kShadowAlignment);
+        short_granule[kShadowAlignment - 1] = tag;
+      }
+    } else {
+      user_ptr = (void *)TagMemoryAligned((uptr)user_ptr, size, 0);
+    }
+  }
+
+  HWASAN_MALLOC_HOOK(user_ptr, size);
+  return user_ptr;
+}
+
+static bool PointerAndMemoryTagsMatch(void *tagged_ptr) {
+  CHECK(tagged_ptr);
+  uptr tagged_uptr = reinterpret_cast<uptr>(tagged_ptr);
+  tag_t mem_tag = *reinterpret_cast<tag_t *>(
+      MemToShadow(reinterpret_cast<uptr>(UntagPtr(tagged_ptr))));
+  return PossiblyShortTagMatches(mem_tag, tagged_uptr, 1);
+}
+
+static void HwasanDeallocate(StackTrace *stack, void *tagged_ptr) {
+  CHECK(tagged_ptr);
+  HWASAN_FREE_HOOK(tagged_ptr);
+
+  if (!PointerAndMemoryTagsMatch(tagged_ptr))
+    ReportInvalidFree(stack, reinterpret_cast<uptr>(tagged_ptr));
+
+  void *untagged_ptr = UntagPtr(tagged_ptr);
+  void *aligned_ptr = reinterpret_cast<void *>(
+      RoundDownTo(reinterpret_cast<uptr>(untagged_ptr), kShadowAlignment));
+  Metadata *meta =
+      reinterpret_cast<Metadata *>(allocator.GetMetaData(aligned_ptr));
+  uptr orig_size = meta->get_requested_size();
+  u32 free_context_id = StackDepotPut(*stack);
+  u32 alloc_context_id = meta->alloc_context_id;
+
+  // Check tail magic.
+  uptr tagged_size = TaggedSize(orig_size);
+  if (flags()->free_checks_tail_magic && orig_size &&
+      tagged_size != orig_size) {
+    uptr tail_size = tagged_size - orig_size - 1;
+    CHECK_LT(tail_size, kShadowAlignment);
+    void *tail_beg = reinterpret_cast<void *>(
+        reinterpret_cast<uptr>(aligned_ptr) + orig_size);
+    if (tail_size && internal_memcmp(tail_beg, tail_magic, tail_size))
+      ReportTailOverwritten(stack, reinterpret_cast<uptr>(tagged_ptr),
+                            orig_size, tail_magic);
+  }
+
+  meta->set_requested_size(0);
+  meta->alloc_context_id = 0;
+  // This memory will not be reused by anyone else, so we are free to keep it
+  // poisoned.
+  Thread *t = GetCurrentThread();
+  if (flags()->max_free_fill_size > 0) {
+    uptr fill_size =
+        Min(TaggedSize(orig_size), (uptr)flags()->max_free_fill_size);
+    internal_memset(aligned_ptr, flags()->free_fill_byte, fill_size);
+  }
+  if (flags()->tag_in_free && malloc_bisect(stack, 0) &&
+      atomic_load_relaxed(&hwasan_allocator_tagging_enabled))
+    TagMemoryAligned(reinterpret_cast<uptr>(aligned_ptr), TaggedSize(orig_size),
+                     t ? t->GenerateRandomTag() : kFallbackFreeTag);
+  if (t) {
+    allocator.Deallocate(t->allocator_cache(), aligned_ptr);
+    if (auto *ha = t->heap_allocations())
+      ha->push({reinterpret_cast<uptr>(tagged_ptr), alloc_context_id,
+                free_context_id, static_cast<u32>(orig_size)});
+  } else {
+    SpinMutexLock l(&fallback_mutex);
+    AllocatorCache *cache = &fallback_allocator_cache;
+    allocator.Deallocate(cache, aligned_ptr);
+  }
+}
+
+static void *HwasanReallocate(StackTrace *stack, void *tagged_ptr_old,
+                              uptr new_size, uptr alignment) {
+  if (!PointerAndMemoryTagsMatch(tagged_ptr_old))
+    ReportInvalidFree(stack, reinterpret_cast<uptr>(tagged_ptr_old));
+
+  void *tagged_ptr_new =
+      HwasanAllocate(stack, new_size, alignment, false /*zeroise*/);
+  if (tagged_ptr_old && tagged_ptr_new) {
+    void *untagged_ptr_old =  UntagPtr(tagged_ptr_old);
+    Metadata *meta =
+        reinterpret_cast<Metadata *>(allocator.GetMetaData(untagged_ptr_old));
+    internal_memcpy(
+        UntagPtr(tagged_ptr_new), untagged_ptr_old,
+        Min(new_size, static_cast<uptr>(meta->get_requested_size())));
+    HwasanDeallocate(stack, tagged_ptr_old);
+  }
+  return tagged_ptr_new;
+}
+
+static void *HwasanCalloc(StackTrace *stack, uptr nmemb, uptr size) {
+  if (UNLIKELY(CheckForCallocOverflow(size, nmemb))) {
+    if (AllocatorMayReturnNull())
+      return nullptr;
+    ReportCallocOverflow(nmemb, size, stack);
+  }
+  return HwasanAllocate(stack, nmemb * size, sizeof(u64), true);
+}
+
+HwasanChunkView FindHeapChunkByAddress(uptr address) {
+  void *block = allocator.GetBlockBegin(reinterpret_cast<void*>(address));
+  if (!block)
+    return HwasanChunkView();
+  Metadata *metadata =
+      reinterpret_cast<Metadata*>(allocator.GetMetaData(block));
+  return HwasanChunkView(reinterpret_cast<uptr>(block), metadata);
+}
+
+static uptr AllocationSize(const void *tagged_ptr) {
+  const void *untagged_ptr = UntagPtr(tagged_ptr);
+  if (!untagged_ptr) return 0;
+  const void *beg = allocator.GetBlockBegin(untagged_ptr);
+  Metadata *b = (Metadata *)allocator.GetMetaData(untagged_ptr);
+  if (b->right_aligned) {
+    if (beg != reinterpret_cast<void *>(RoundDownTo(
+                   reinterpret_cast<uptr>(untagged_ptr), kShadowAlignment)))
+      return 0;
+  } else {
+    if (beg != untagged_ptr) return 0;
+  }
+  return b->get_requested_size();
+}
+
+void *hwasan_malloc(uptr size, StackTrace *stack) {
+  return SetErrnoOnNull(HwasanAllocate(stack, size, sizeof(u64), false));
+}
+
+void *hwasan_calloc(uptr nmemb, uptr size, StackTrace *stack) {
+  return SetErrnoOnNull(HwasanCalloc(stack, nmemb, size));
+}
+
+void *hwasan_realloc(void *ptr, uptr size, StackTrace *stack) {
+  if (!ptr)
+    return SetErrnoOnNull(HwasanAllocate(stack, size, sizeof(u64), false));
+  if (size == 0) {
+    HwasanDeallocate(stack, ptr);
+    return nullptr;
+  }
+  return SetErrnoOnNull(HwasanReallocate(stack, ptr, size, sizeof(u64)));
+}
+
+void *hwasan_reallocarray(void *ptr, uptr nmemb, uptr size, StackTrace *stack) {
+  if (UNLIKELY(CheckForCallocOverflow(size, nmemb))) {
+    errno = errno_ENOMEM;
+    if (AllocatorMayReturnNull())
+      return nullptr;
+    ReportReallocArrayOverflow(nmemb, size, stack);
+  }
+  return hwasan_realloc(ptr, nmemb * size, stack);
+}
+
+void *hwasan_valloc(uptr size, StackTrace *stack) {
+  return SetErrnoOnNull(
+      HwasanAllocate(stack, size, GetPageSizeCached(), false));
+}
+
+void *hwasan_pvalloc(uptr size, StackTrace *stack) {
+  uptr PageSize = GetPageSizeCached();
+  if (UNLIKELY(CheckForPvallocOverflow(size, PageSize))) {
+    errno = errno_ENOMEM;
+    if (AllocatorMayReturnNull())
+      return nullptr;
+    ReportPvallocOverflow(size, stack);
+  }
+  // pvalloc(0) should allocate one page.
+  size = size ? RoundUpTo(size, PageSize) : PageSize;
+  return SetErrnoOnNull(HwasanAllocate(stack, size, PageSize, false));
+}
+
+void *hwasan_aligned_alloc(uptr alignment, uptr size, StackTrace *stack) {
+  if (UNLIKELY(!CheckAlignedAllocAlignmentAndSize(alignment, size))) {
+    errno = errno_EINVAL;
+    if (AllocatorMayReturnNull())
+      return nullptr;
+    ReportInvalidAlignedAllocAlignment(size, alignment, stack);
+  }
+  return SetErrnoOnNull(HwasanAllocate(stack, size, alignment, false));
+}
+
+void *hwasan_memalign(uptr alignment, uptr size, StackTrace *stack) {
+  if (UNLIKELY(!IsPowerOfTwo(alignment))) {
+    errno = errno_EINVAL;
+    if (AllocatorMayReturnNull())
+      return nullptr;
+    ReportInvalidAllocationAlignment(alignment, stack);
+  }
+  return SetErrnoOnNull(HwasanAllocate(stack, size, alignment, false));
+}
+
+int hwasan_posix_memalign(void **memptr, uptr alignment, uptr size,
+                        StackTrace *stack) {
+  if (UNLIKELY(!CheckPosixMemalignAlignment(alignment))) {
+    if (AllocatorMayReturnNull())
+      return errno_EINVAL;
+    ReportInvalidPosixMemalignAlignment(alignment, stack);
+  }
+  void *ptr = HwasanAllocate(stack, size, alignment, false);
+  if (UNLIKELY(!ptr))
+    // OOM error is already taken care of by HwasanAllocate.
+    return errno_ENOMEM;
+  CHECK(IsAligned((uptr)ptr, alignment));
+  *(void **)UntagPtr(memptr) = ptr;
+  return 0;
+}
+
+void hwasan_free(void *ptr, StackTrace *stack) {
+  return HwasanDeallocate(stack, ptr);
+}
+
+}  // namespace __hwasan
+
+using namespace __hwasan;
+
+void __hwasan_enable_allocator_tagging() {
+  atomic_store_relaxed(&hwasan_allocator_tagging_enabled, 1);
+}
+
+void __hwasan_disable_allocator_tagging() {
+  atomic_store_relaxed(&hwasan_allocator_tagging_enabled, 0);
+}
+
+uptr __sanitizer_get_current_allocated_bytes() {
+  uptr stats[AllocatorStatCount];
+  allocator.GetStats(stats);
+  return stats[AllocatorStatAllocated];
+}
+
+uptr __sanitizer_get_heap_size() {
+  uptr stats[AllocatorStatCount];
+  allocator.GetStats(stats);
+  return stats[AllocatorStatMapped];
+}
+
+uptr __sanitizer_get_free_bytes() { return 1; }
+
+uptr __sanitizer_get_unmapped_bytes() { return 1; }
+
+uptr __sanitizer_get_estimated_allocated_size(uptr size) { return size; }
+
+int __sanitizer_get_ownership(const void *p) { return AllocationSize(p) != 0; }
+
+uptr __sanitizer_get_allocated_size(const void *p) { return AllocationSize(p); }
diff --git a/libsanitizer/hwasan/hwasan_allocator.h b/libsanitizer/hwasan/hwasan_allocator.h
new file mode 100644
index 00000000000..43670a6a3fb
--- /dev/null
+++ b/libsanitizer/hwasan/hwasan_allocator.h
@@ -0,0 +1,107 @@
+//===-- hwasan_allocator.h --------------------------------------*- C++ -*-===//
+//
+// 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 a part of HWAddressSanitizer.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef HWASAN_ALLOCATOR_H
+#define HWASAN_ALLOCATOR_H
+
+#include "sanitizer_common/sanitizer_allocator.h"
+#include "sanitizer_common/sanitizer_allocator_checks.h"
+#include "sanitizer_common/sanitizer_allocator_interface.h"
+#include "sanitizer_common/sanitizer_allocator_report.h"
+#include "sanitizer_common/sanitizer_common.h"
+#include "sanitizer_common/sanitizer_ring_buffer.h"
+#include "hwasan_poisoning.h"
+
+#if !defined(__aarch64__) && !defined(__x86_64__)
+#error Unsupported platform
+#endif
+
+namespace __hwasan {
+
+struct Metadata {
+  u32 requested_size_low;
+  u32 requested_size_high : 31;
+  u32 right_aligned : 1;
+  u32 alloc_context_id;
+  u64 get_requested_size() {
+    return (static_cast<u64>(requested_size_high) << 32) + requested_size_low;
+  }
+  void set_requested_size(u64 size) {
+    requested_size_low = size & ((1ul << 32) - 1);
+    requested_size_high = size >> 32;
+  }
+};
+
+struct HwasanMapUnmapCallback {
+  void OnMap(uptr p, uptr size) const { UpdateMemoryUsage(); }
+  void OnUnmap(uptr p, uptr size) const {
+    // We are about to unmap a chunk of user memory.
+    // It can return as user-requested mmap() or another thread stack.
+    // Make it accessible with zero-tagged pointer.
+    TagMemory(p, size, 0);
+  }
+};
+
+static const uptr kMaxAllowedMallocSize = 1UL << 40;  // 1T
+
+struct AP64 {
+  static const uptr kSpaceBeg = ~0ULL;
+  static const uptr kSpaceSize = 0x2000000000ULL;
+  static const uptr kMetadataSize = sizeof(Metadata);
+  typedef __sanitizer::VeryDenseSizeClassMap SizeClassMap;
+  using AddressSpaceView = LocalAddressSpaceView;
+  typedef HwasanMapUnmapCallback MapUnmapCallback;
+  static const uptr kFlags = 0;
+};
+typedef SizeClassAllocator64<AP64> PrimaryAllocator;
+typedef CombinedAllocator<PrimaryAllocator> Allocator;
+typedef Allocator::AllocatorCache AllocatorCache;
+
+void AllocatorSwallowThreadLocalCache(AllocatorCache *cache);
+
+class HwasanChunkView {
+ public:
+  HwasanChunkView() : block_(0), metadata_(nullptr) {}
+  HwasanChunkView(uptr block, Metadata *metadata)
+      : block_(block), metadata_(metadata) {}
+  bool IsAllocated() const;    // Checks if the memory is currently allocated
+  uptr Beg() const;            // First byte of user memory
+  uptr End() const;            // Last byte of user memory
+  uptr UsedSize() const;       // Size requested by the user
+  uptr ActualSize() const;     // Size allocated by the allocator.
+  u32 GetAllocStackId() const;
+  bool FromSmallHeap() const;
+ private:
+  uptr block_;
+  Metadata *const metadata_;
+};
+
+HwasanChunkView FindHeapChunkByAddress(uptr address);
+
+// Information about one (de)allocation that happened in the past.
+// These are recorded in a thread-local ring buffer.
+// TODO: this is currently 24 bytes (20 bytes + alignment).
+// Compress it to 16 bytes or extend it to be more useful.
+struct HeapAllocationRecord {
+  uptr tagged_addr;
+  u32  alloc_context_id;
+  u32  free_context_id;
+  u32  requested_size;
+};
+
+typedef RingBuffer<HeapAllocationRecord> HeapAllocationsRingBuffer;
+
+void GetAllocatorStats(AllocatorStatCounters s);
+
+} // namespace __hwasan
+
+#endif // HWASAN_ALLOCATOR_H
diff --git a/libsanitizer/hwasan/hwasan_checks.h b/libsanitizer/hwasan/hwasan_checks.h
new file mode 100644
index 00000000000..a8de0fef20f
--- /dev/null
+++ b/libsanitizer/hwasan/hwasan_checks.h
@@ -0,0 +1,124 @@
+//===-- hwasan_checks.h -----------------------------------------*- C++ -*-===//
+//
+// 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 a part of HWAddressSanitizer.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef HWASAN_CHECKS_H
+#define HWASAN_CHECKS_H
+
+#include "hwasan_mapping.h"
+#include "sanitizer_common/sanitizer_common.h"
+
+namespace __hwasan {
+template <unsigned X>
+__attribute__((always_inline)) static void SigTrap(uptr p) {
+#if defined(__aarch64__)
+  (void)p;
+  // 0x900 is added to do not interfere with the kernel use of lower values of
+  // brk immediate.
+  register uptr x0 asm("x0") = p;
+  asm("brk %1\n\t" ::"r"(x0), "n"(0x900 + X));
+#elif defined(__x86_64__)
+  // INT3 + NOP DWORD ptr [EAX + X] to pass X to our signal handler, 5 bytes
+  // total. The pointer is passed via rdi.
+  // 0x40 is added as a safeguard, to help distinguish our trap from others and
+  // to avoid 0 offsets in the command (otherwise it'll be reduced to a
+  // different nop command, the three bytes one).
+  asm volatile(
+      "int3\n"
+      "nopl %c0(%%rax)\n" ::"n"(0x40 + X),
+      "D"(p));
+#else
+  // FIXME: not always sigill.
+  __builtin_trap();
+#endif
+  // __builtin_unreachable();
+}
+
+// Version with access size which is not power of 2
+template <unsigned X>
+__attribute__((always_inline)) static void SigTrap(uptr p, uptr size) {
+#if defined(__aarch64__)
+  register uptr x0 asm("x0") = p;
+  register uptr x1 asm("x1") = size;
+  asm("brk %2\n\t" ::"r"(x0), "r"(x1), "n"(0x900 + X));
+#elif defined(__x86_64__)
+  // Size is stored in rsi.
+  asm volatile(
+      "int3\n"
+      "nopl %c0(%%rax)\n" ::"n"(0x40 + X),
+      "D"(p), "S"(size));
+#else
+  __builtin_trap();
+#endif
+  // __builtin_unreachable();
+}
+
+__attribute__((always_inline, nodebug)) static bool PossiblyShortTagMatches(
+    tag_t mem_tag, uptr ptr, uptr sz) {
+  tag_t ptr_tag = GetTagFromPointer(ptr);
+  if (ptr_tag == mem_tag)
+    return true;
+  if (mem_tag >= kShadowAlignment)
+    return false;
+  if ((ptr & (kShadowAlignment - 1)) + sz > mem_tag)
+    return false;
+#ifndef __aarch64__
+  ptr = UntagAddr(ptr);
+#endif
+  return *(u8 *)(ptr | (kShadowAlignment - 1)) == ptr_tag;
+}
+
+enum class ErrorAction { Abort, Recover };
+enum class AccessType { Load, Store };
+
+template <ErrorAction EA, AccessType AT, unsigned LogSize>
+__attribute__((always_inline, nodebug)) static void CheckAddress(uptr p) {
+  uptr ptr_raw = p & ~kAddressTagMask;
+  tag_t mem_tag = *(tag_t *)MemToShadow(ptr_raw);
+  if (UNLIKELY(!PossiblyShortTagMatches(mem_tag, p, 1 << LogSize))) {
+    SigTrap<0x20 * (EA == ErrorAction::Recover) +
+            0x10 * (AT == AccessType::Store) + LogSize>(p);
+    if (EA == ErrorAction::Abort)
+      __builtin_unreachable();
+  }
+}
+
+template <ErrorAction EA, AccessType AT>
+__attribute__((always_inline, nodebug)) static void CheckAddressSized(uptr p,
+                                                                      uptr sz) {
+  if (sz == 0)
+    return;
+  tag_t ptr_tag = GetTagFromPointer(p);
+  uptr ptr_raw = p & ~kAddressTagMask;
+  tag_t *shadow_first = (tag_t *)MemToShadow(ptr_raw);
+  tag_t *shadow_last = (tag_t *)MemToShadow(ptr_raw + sz);
+  for (tag_t *t = shadow_first; t < shadow_last; ++t)
+    if (UNLIKELY(ptr_tag != *t)) {
+      SigTrap<0x20 * (EA == ErrorAction::Recover) +
+              0x10 * (AT == AccessType::Store) + 0xf>(p, sz);
+      if (EA == ErrorAction::Abort)
+        __builtin_unreachable();
+    }
+  uptr end = p + sz;
+  uptr tail_sz = end & 0xf;
+  if (UNLIKELY(tail_sz != 0 &&
+               !PossiblyShortTagMatches(
+                   *shadow_last, end & ~(kShadowAlignment - 1), tail_sz))) {
+    SigTrap<0x20 * (EA == ErrorAction::Recover) +
+            0x10 * (AT == AccessType::Store) + 0xf>(p, sz);
+    if (EA == ErrorAction::Abort)
+      __builtin_unreachable();
+  }
+}
+
+}  // end namespace __hwasan
+
+#endif  // HWASAN_CHECKS_H
diff --git a/libsanitizer/hwasan/hwasan_dynamic_shadow.cpp b/libsanitizer/hwasan/hwasan_dynamic_shadow.cpp
new file mode 100644
index 00000000000..12730b29bae
--- /dev/null
+++ b/libsanitizer/hwasan/hwasan_dynamic_shadow.cpp
@@ -0,0 +1,126 @@
+//===-- hwasan_dynamic_shadow.cpp -------------------------------*- C++ -*-===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This file is a part of HWAddressSanitizer. It reserves dynamic shadow memory
+/// region and handles ifunc resolver case, when necessary.
+///
+//===----------------------------------------------------------------------===//
+
+#include "hwasan.h"
+#include "hwasan_dynamic_shadow.h"
+#include "hwasan_mapping.h"
+#include "sanitizer_common/sanitizer_common.h"
+#include "sanitizer_common/sanitizer_posix.h"
+
+#include <elf.h>
+#include <link.h>
+
+// The code in this file needs to run in an unrelocated binary. It should not
+// access any external symbol, including its own non-hidden globals.
+
+#if SANITIZER_ANDROID
+extern "C" {
+
+INTERFACE_ATTRIBUTE void __hwasan_shadow();
+decltype(__hwasan_shadow)* __hwasan_premap_shadow();
+
+}  // extern "C"
+
+namespace __hwasan {
+
+// Conservative upper limit.
+static uptr PremapShadowSize() {
+  return RoundUpTo(GetMaxVirtualAddress() >> kShadowScale,
+                   GetMmapGranularity());
+}
+
+static uptr PremapShadow() {
+  return MapDynamicShadow(PremapShadowSize(), kShadowScale,
+                          kShadowBaseAlignment, kHighMemEnd);
+}
+
+static bool IsPremapShadowAvailable() {
+  const uptr shadow = reinterpret_cast<uptr>(&__hwasan_shadow);
+  const uptr resolver = reinterpret_cast<uptr>(&__hwasan_premap_shadow);
+  // shadow == resolver is how Android KitKat and older handles ifunc.
+  // shadow == 0 just in case.
+  return shadow != 0 && shadow != resolver;
+}
+
+static uptr FindPremappedShadowStart(uptr shadow_size_bytes) {
+  const uptr granularity = GetMmapGranularity();
+  const uptr shadow_start = reinterpret_cast<uptr>(&__hwasan_shadow);
+  const uptr premap_shadow_size = PremapShadowSize();
+  const uptr shadow_size = RoundUpTo(shadow_size_bytes, granularity);
+
+  // We may have mapped too much. Release extra memory.
+  UnmapFromTo(shadow_start + shadow_size, shadow_start + premap_shadow_size);
+  return shadow_start;
+}
+
+}  // namespace __hwasan
+
+extern "C" {
+
+decltype(__hwasan_shadow)* __hwasan_premap_shadow() {
+  // The resolver might be called multiple times. Map the shadow just once.
+  static __sanitizer::uptr shadow = 0;
+  if (!shadow)
+    shadow = __hwasan::PremapShadow();
+  return reinterpret_cast<decltype(__hwasan_shadow)*>(shadow);
+}
+
+// __hwasan_shadow is a "function" that has the same address as the first byte
+// of the shadow mapping.
+INTERFACE_ATTRIBUTE __attribute__((ifunc("__hwasan_premap_shadow")))
+void __hwasan_shadow();
+
+extern __attribute((weak, visibility("hidden"))) ElfW(Rela) __rela_iplt_start[],
+    __rela_iplt_end[];
+
+}  // extern "C"
+
+namespace __hwasan {
+
+void InitShadowGOT() {
+  // Call the ifunc resolver for __hwasan_shadow and fill in its GOT entry. This
+  // needs to be done before other ifunc resolvers (which are handled by libc)
+  // because a resolver might read __hwasan_shadow.
+  typedef ElfW(Addr) (*ifunc_resolver_t)(void);
+  for (ElfW(Rela) *r = __rela_iplt_start; r != __rela_iplt_end; ++r) {
+    ElfW(Addr)* offset = reinterpret_cast<ElfW(Addr)*>(r->r_offset);
+    ElfW(Addr) resolver = r->r_addend;
+    if (resolver == reinterpret_cast<ElfW(Addr)>(&__hwasan_premap_shadow)) {
+      *offset = reinterpret_cast<ifunc_resolver_t>(resolver)();
+      break;
+    }
+  }
+}
+
+uptr FindDynamicShadowStart(uptr shadow_size_bytes) {
+  if (IsPremapShadowAvailable())
+    return FindPremappedShadowStart(shadow_size_bytes);
+  return MapDynamicShadow(shadow_size_bytes, kShadowScale, kShadowBaseAlignment,
+                          kHighMemEnd);
+}
+
+}  // namespace __hwasan
+#else
+namespace __hwasan {
+
+void InitShadowGOT() {}
+
+uptr FindDynamicShadowStart(uptr shadow_size_bytes) {
+  return MapDynamicShadow(shadow_size_bytes, kShadowScale, kShadowBaseAlignment,
+                          kHighMemEnd);
+}
+
+}  // namespace __hwasan
+
+#endif  // SANITIZER_ANDROID
diff --git a/libsanitizer/hwasan/hwasan_dynamic_shadow.h b/libsanitizer/hwasan/hwasan_dynamic_shadow.h
new file mode 100644
index 00000000000..3c2e7c716a3
--- /dev/null
+++ b/libsanitizer/hwasan/hwasan_dynamic_shadow.h
@@ -0,0 +1,27 @@
+//===-- hwasan_dynamic_shadow.h ---------------------------------*- C++ -*-===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This file is a part of HWAddressSanitizer. It reserves dynamic shadow memory
+/// region.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef HWASAN_PREMAP_SHADOW_H
+#define HWASAN_PREMAP_SHADOW_H
+
+#include "sanitizer_common/sanitizer_internal_defs.h"
+
+namespace __hwasan {
+
+uptr FindDynamicShadowStart(uptr shadow_size_bytes);
+void InitShadowGOT();
+
+}  // namespace __hwasan
+
+#endif  // HWASAN_PREMAP_SHADOW_H
diff --git a/libsanitizer/hwasan/hwasan_exceptions.cpp b/libsanitizer/hwasan/hwasan_exceptions.cpp
new file mode 100644
index 00000000000..169e7876cb5
--- /dev/null
+++ b/libsanitizer/hwasan/hwasan_exceptions.cpp
@@ -0,0 +1,67 @@
+//===-- hwasan_exceptions.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 a part of HWAddressSanitizer.
+//
+// HWAddressSanitizer runtime.
+//===----------------------------------------------------------------------===//
+
+#include "hwasan_poisoning.h"
+#include "sanitizer_common/sanitizer_common.h"
+
+#include <unwind.h>
+
+using namespace __hwasan;
+using namespace __sanitizer;
+
+typedef _Unwind_Reason_Code PersonalityFn(int version, _Unwind_Action actions,
+                                          uint64_t exception_class,
+                                          _Unwind_Exception* unwind_exception,
+                                          _Unwind_Context* context);
+
+// Pointers to the _Unwind_GetGR and _Unwind_GetCFA functions are passed in
+// instead of being called directly. This is to handle cases where the unwinder
+// is statically linked and the sanitizer runtime and the program are linked
+// against different unwinders. The _Unwind_Context data structure is opaque so
+// it may be incompatible between unwinders.
+typedef _Unwind_Word GetGRFn(_Unwind_Context* context, int index);
+typedef _Unwind_Word GetCFAFn(_Unwind_Context* context);
+
+extern "C" SANITIZER_INTERFACE_ATTRIBUTE _Unwind_Reason_Code
+__hwasan_personality_wrapper(int version, _Unwind_Action actions,
+                             uint64_t exception_class,
+                             _Unwind_Exception* unwind_exception,
+                             _Unwind_Context* context,
+                             PersonalityFn* real_personality, GetGRFn* get_gr,
+                             GetCFAFn* get_cfa) {
+  _Unwind_Reason_Code rc;
+  if (real_personality)
+    rc = real_personality(version, actions, exception_class, unwind_exception,
+                          context);
+  else
+    rc = _URC_CONTINUE_UNWIND;
+
+  // We only untag frames without a landing pad because landing pads are
+  // responsible for untagging the stack themselves if they resume.
+  //
+  // Here we assume that the frame record appears after any locals. This is not
+  // required by AAPCS but is a requirement for HWASAN instrumented functions.
+  if ((actions & _UA_CLEANUP_PHASE) && rc == _URC_CONTINUE_UNWIND) {
+#if defined(__x86_64__)
+    uptr fp = get_gr(context, 6); // rbp
+#elif defined(__aarch64__)
+    uptr fp = get_gr(context, 29); // x29
+#else
+#error Unsupported architecture
+#endif
+    uptr sp = get_cfa(context);
+    TagMemory(sp, fp - sp, 0);
+  }
+
+  return rc;
+}
diff --git a/libsanitizer/hwasan/hwasan_flags.h b/libsanitizer/hwasan/hwasan_flags.h
new file mode 100644
index 00000000000..0a6998f675d
--- /dev/null
+++ b/libsanitizer/hwasan/hwasan_flags.h
@@ -0,0 +1,29 @@
+//===-- hwasan_flags.h ------------------------------------------*- C++ -*-===//
+//
+// 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 a part of HWAddressSanitizer.
+//
+//===----------------------------------------------------------------------===//
+#ifndef HWASAN_FLAGS_H
+#define HWASAN_FLAGS_H
+
+namespace __hwasan {
+
+struct Flags {
+#define HWASAN_FLAG(Type, Name, DefaultValue, Description) Type Name;
+#include "hwasan_flags.inc"
+#undef HWASAN_FLAG
+
+  void SetDefaults();
+};
+
+Flags *flags();
+
+}  // namespace __hwasan
+
+#endif  // HWASAN_FLAGS_H
diff --git a/libsanitizer/hwasan/hwasan_flags.inc b/libsanitizer/hwasan/hwasan_flags.inc
new file mode 100644
index 00000000000..8e431d9c4ff
--- /dev/null
+++ b/libsanitizer/hwasan/hwasan_flags.inc
@@ -0,0 +1,74 @@
+//===-- hwasan_flags.inc ----------------------------------------*- C++ -*-===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+//
+// Hwasan runtime flags.
+//
+//===----------------------------------------------------------------------===//
+#ifndef HWASAN_FLAG
+# error "Define HWASAN_FLAG prior to including this file!"
+#endif
+
+// HWASAN_FLAG(Type, Name, DefaultValue, Description)
+// See COMMON_FLAG in sanitizer_flags.inc for more details.
+
+HWASAN_FLAG(bool, verbose_threads, false,
+            "inform on thread creation/destruction")
+HWASAN_FLAG(bool, tag_in_malloc, true, "")
+HWASAN_FLAG(bool, tag_in_free, true, "")
+HWASAN_FLAG(bool, print_stats, false, "")
+HWASAN_FLAG(bool, halt_on_error, true, "")
+HWASAN_FLAG(bool, atexit, false, "")
+
+// Test only flag to disable malloc/realloc/free memory tagging on startup.
+// Tagging can be reenabled with __hwasan_enable_allocator_tagging().
+HWASAN_FLAG(bool, disable_allocator_tagging, false, "")
+
+// If false, use simple increment of a thread local counter to generate new
+// tags.
+HWASAN_FLAG(bool, random_tags, true, "")
+
+HWASAN_FLAG(
+    int, max_malloc_fill_size, 0,
+    "HWASan allocator flag. max_malloc_fill_size is the maximal amount of "
+    "bytes that will be filled with malloc_fill_byte on malloc.")
+
+HWASAN_FLAG(bool, free_checks_tail_magic, 1,
+    "If set, free() will check the magic values "
+    "to the right of the allocated object "
+    "if the allocation size is not a divident of the granule size")
+HWASAN_FLAG(
+    int, max_free_fill_size, 0,
+    "HWASan allocator flag. max_free_fill_size is the maximal amount of "
+    "bytes that will be filled with free_fill_byte during free.")
+HWASAN_FLAG(int, malloc_fill_byte, 0xbe,
+          "Value used to fill the newly allocated memory.")
+HWASAN_FLAG(int, free_fill_byte, 0x55,
+          "Value used to fill deallocated memory.")
+HWASAN_FLAG(int, heap_history_size, 1023,
+          "The number of heap (de)allocations remembered per thread. "
+          "Affects the quality of heap-related reports, but not the ability "
+          "to find bugs.")
+HWASAN_FLAG(bool, export_memory_stats, true,
+            "Export up-to-date memory stats through /proc")
+HWASAN_FLAG(int, stack_history_size, 1024,
+            "The number of stack frames remembered per thread. "
+            "Affects the quality of stack-related reports, but not the ability "
+            "to find bugs.")
+
+// Malloc / free bisection. Only tag malloc and free calls when a hash of
+// allocation size and stack trace is between malloc_bisect_left and
+// malloc_bisect_right (both inclusive). [0, 0] range is special and disables
+// bisection (i.e. everything is tagged). Once the range is narrowed down
+// enough, use malloc_bisect_dump to see interesting allocations.
+HWASAN_FLAG(uptr, malloc_bisect_left, 0,
+            "Left bound of malloc bisection, inclusive.")
+HWASAN_FLAG(uptr, malloc_bisect_right, 0,
+            "Right bound of malloc bisection, inclusive.")
+HWASAN_FLAG(bool, malloc_bisect_dump, false,
+            "Print all allocations within [malloc_bisect_left, "
+            "malloc_bisect_right] range ")
diff --git a/libsanitizer/hwasan/hwasan_globals.cpp b/libsanitizer/hwasan/hwasan_globals.cpp
new file mode 100644
index 00000000000..d71bcd792e1
--- /dev/null
+++ b/libsanitizer/hwasan/hwasan_globals.cpp
@@ -0,0 +1,91 @@
+//===-- hwasan_globals.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 a part of HWAddressSanitizer.
+//
+// HWAddressSanitizer globals-specific runtime.
+//===----------------------------------------------------------------------===//
+
+#include "hwasan_globals.h"
+
+namespace __hwasan {
+
+enum { NT_LLVM_HWASAN_GLOBALS = 3 };
+struct hwasan_global_note {
+  s32 begin_relptr;
+  s32 end_relptr;
+};
+
+// Check that the given library meets the code model requirements for tagged
+// globals. These properties are not checked at link time so they need to be
+// checked at runtime.
+static void CheckCodeModel(ElfW(Addr) base, const ElfW(Phdr) * phdr,
+                           ElfW(Half) phnum) {
+  ElfW(Addr) min_addr = -1ull, max_addr = 0;
+  for (unsigned i = 0; i != phnum; ++i) {
+    if (phdr[i].p_type != PT_LOAD)
+      continue;
+    ElfW(Addr) lo = base + phdr[i].p_vaddr, hi = lo + phdr[i].p_memsz;
+    if (min_addr > lo)
+      min_addr = lo;
+    if (max_addr < hi)
+      max_addr = hi;
+  }
+
+  if (max_addr - min_addr > 1ull << 32) {
+    Report("FATAL: HWAddressSanitizer: library size exceeds 2^32\n");
+    Die();
+  }
+  if (max_addr > 1ull << 48) {
+    Report("FATAL: HWAddressSanitizer: library loaded above address 2^48\n");
+    Die();
+  }
+}
+
+ArrayRef<const hwasan_global> HwasanGlobalsFor(ElfW(Addr) base,
+                                               const ElfW(Phdr) * phdr,
+                                               ElfW(Half) phnum) {
+  // Read the phdrs from this DSO.
+  for (unsigned i = 0; i != phnum; ++i) {
+    if (phdr[i].p_type != PT_NOTE)
+      continue;
+
+    const char *note = reinterpret_cast<const char *>(base + phdr[i].p_vaddr);
+    const char *nend = note + phdr[i].p_memsz;
+
+    // Traverse all the notes until we find a HWASan note.
+    while (note < nend) {
+      auto *nhdr = reinterpret_cast<const ElfW(Nhdr) *>(note);
+      const char *name = note + sizeof(ElfW(Nhdr));
+      const char *desc = name + RoundUpTo(nhdr->n_namesz, 4);
+
+      // Discard non-HWASan-Globals notes.
+      if (nhdr->n_type != NT_LLVM_HWASAN_GLOBALS ||
+          internal_strcmp(name, "LLVM") != 0) {
+        note = desc + RoundUpTo(nhdr->n_descsz, 4);
+        continue;
+      }
+
+      // Only libraries with instrumented globals need to be checked against the
+      // code model since they use relocations that aren't checked at link time.
+      CheckCodeModel(base, phdr, phnum);
+
+      auto *global_note = reinterpret_cast<const hwasan_global_note *>(desc);
+      auto *globals_begin = reinterpret_cast<const hwasan_global *>(
+          note + global_note->begin_relptr);
+      auto *globals_end = reinterpret_cast<const hwasan_global *>(
+          note + global_note->end_relptr);
+
+      return {globals_begin, globals_end};
+    }
+  }
+
+  return {};
+}
+
+}  // namespace __hwasan
diff --git a/libsanitizer/hwasan/hwasan_globals.h b/libsanitizer/hwasan/hwasan_globals.h
new file mode 100644
index 00000000000..fd7adf7a058
--- /dev/null
+++ b/libsanitizer/hwasan/hwasan_globals.h
@@ -0,0 +1,49 @@
+//===-- hwasan_globals.h ----------------------------------------*- C++ -*-===//
+//
+// 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 a part of HWAddressSanitizer.
+//
+// Private Hwasan header.
+//===----------------------------------------------------------------------===//
+
+#ifndef HWASAN_GLOBALS_H
+#define HWASAN_GLOBALS_H
+
+#include <link.h>
+
+#include "sanitizer_common/sanitizer_common.h"
+#include "sanitizer_common/sanitizer_internal_defs.h"
+
+namespace __hwasan {
+// This object should only ever be casted over the global (i.e. not constructed)
+// in the ELF PT_NOTE in order for `addr()` to work correctly.
+struct hwasan_global {
+  // The size of this global variable. Note that the size in the descriptor is
+  // max 1 << 24. Larger globals have multiple descriptors.
+  uptr size() const { return info & 0xffffff; }
+  // The fully-relocated address of this global.
+  uptr addr() const { return reinterpret_cast<uintptr_t>(this) + gv_relptr; }
+  // The static tag of this global.
+  u8 tag() const { return info >> 24; };
+
+  // The relative address between the start of the descriptor for the HWASan
+  // global (in the PT_NOTE), and the fully relocated address of the global.
+  s32 gv_relptr;
+  u32 info;
+};
+
+// Walk through the specific DSO (as specified by the base, phdr, and phnum),
+// and return the range of the [beginning, end) of the HWASan globals descriptor
+// array.
+ArrayRef<const hwasan_global> HwasanGlobalsFor(ElfW(Addr) base,
+                                               const ElfW(Phdr) * phdr,
+                                               ElfW(Half) phnum);
+
+}  // namespace __hwasan
+
+#endif  // HWASAN_GLOBALS_H
diff --git a/libsanitizer/hwasan/hwasan_interceptors.cpp b/libsanitizer/hwasan/hwasan_interceptors.cpp
new file mode 100644
index 00000000000..44e569ee6d7
--- /dev/null
+++ b/libsanitizer/hwasan/hwasan_interceptors.cpp
@@ -0,0 +1,349 @@
+//===-- hwasan_interceptors.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 a part of HWAddressSanitizer.
+//
+// Interceptors for standard library functions.
+//
+// FIXME: move as many interceptors as possible into
+// sanitizer_common/sanitizer_common_interceptors.h
+//===----------------------------------------------------------------------===//
+
+#include "interception/interception.h"
+#include "hwasan.h"
+#include "hwasan_allocator.h"
+#include "hwasan_mapping.h"
+#include "hwasan_thread.h"
+#include "hwasan_poisoning.h"
+#include "hwasan_report.h"
+#include "sanitizer_common/sanitizer_platform_limits_posix.h"
+#include "sanitizer_common/sanitizer_allocator.h"
+#include "sanitizer_common/sanitizer_allocator_interface.h"
+#include "sanitizer_common/sanitizer_allocator_internal.h"
+#include "sanitizer_common/sanitizer_atomic.h"
+#include "sanitizer_common/sanitizer_common.h"
+#include "sanitizer_common/sanitizer_errno.h"
+#include "sanitizer_common/sanitizer_stackdepot.h"
+#include "sanitizer_common/sanitizer_libc.h"
+#include "sanitizer_common/sanitizer_linux.h"
+#include "sanitizer_common/sanitizer_tls_get_addr.h"
+
+#include <stdarg.h>
+// ACHTUNG! No other system header includes in this file.
+// Ideally, we should get rid of stdarg.h as well.
+
+using namespace __hwasan;
+
+using __sanitizer::memory_order;
+using __sanitizer::atomic_load;
+using __sanitizer::atomic_store;
+using __sanitizer::atomic_uintptr_t;
+
+static uptr allocated_for_dlsym;
+static const uptr kDlsymAllocPoolSize = 1024;
+static uptr alloc_memory_for_dlsym[kDlsymAllocPoolSize];
+
+static bool IsInDlsymAllocPool(const void *ptr) {
+  uptr off = (uptr)ptr - (uptr)alloc_memory_for_dlsym;
+  return off < sizeof(alloc_memory_for_dlsym);
+}
+
+static void *AllocateFromLocalPool(uptr size_in_bytes) {
+  uptr size_in_words = RoundUpTo(size_in_bytes, kWordSize) / kWordSize;
+  void *mem = (void *)&alloc_memory_for_dlsym[allocated_for_dlsym];
+  allocated_for_dlsym += size_in_words;
+  CHECK_LT(allocated_for_dlsym, kDlsymAllocPoolSize);
+  return mem;
+}
+
+#define ENSURE_HWASAN_INITED() do { \
+  CHECK(!hwasan_init_is_running); \
+  if (!hwasan_inited) { \
+    __hwasan_init(); \
+  } \
+} while (0)
+
+
+int __sanitizer_posix_memalign(void **memptr, uptr alignment, uptr size) {
+  GET_MALLOC_STACK_TRACE;
+  CHECK_NE(memptr, 0);
+  int res = hwasan_posix_memalign(memptr, alignment, size, &stack);
+  return res;
+}
+
+void * __sanitizer_memalign(uptr alignment, uptr size) {
+  GET_MALLOC_STACK_TRACE;
+  return hwasan_memalign(alignment, size, &stack);
+}
+
+void * __sanitizer_aligned_alloc(uptr alignment, uptr size) {
+  GET_MALLOC_STACK_TRACE;
+  return hwasan_aligned_alloc(alignment, size, &stack);
+}
+
+void * __sanitizer___libc_memalign(uptr alignment, uptr size) {
+  GET_MALLOC_STACK_TRACE;
+  void *ptr = hwasan_memalign(alignment, size, &stack);
+  if (ptr)
+    DTLS_on_libc_memalign(ptr, size);
+  return ptr;
+}
+
+void * __sanitizer_valloc(uptr size) {
+  GET_MALLOC_STACK_TRACE;
+  return hwasan_valloc(size, &stack);
+}
+
+void * __sanitizer_pvalloc(uptr size) {
+  GET_MALLOC_STACK_TRACE;
+  return hwasan_pvalloc(size, &stack);
+}
+
+void __sanitizer_free(void *ptr) {
+  GET_MALLOC_STACK_TRACE;
+  if (!ptr || UNLIKELY(IsInDlsymAllocPool(ptr))) return;
+  hwasan_free(ptr, &stack);
+}
+
+void __sanitizer_cfree(void *ptr) {
+  GET_MALLOC_STACK_TRACE;
+  if (!ptr || UNLIKELY(IsInDlsymAllocPool(ptr))) return;
+  hwasan_free(ptr, &stack);
+}
+
+uptr __sanitizer_malloc_usable_size(const void *ptr) {
+  return __sanitizer_get_allocated_size(ptr);
+}
+
+struct __sanitizer_struct_mallinfo __sanitizer_mallinfo() {
+  __sanitizer_struct_mallinfo sret;
+  internal_memset(&sret, 0, sizeof(sret));
+  return sret;
+}
+
+int __sanitizer_mallopt(int cmd, int value) {
+  return 0;
+}
+
+void __sanitizer_malloc_stats(void) {
+  // FIXME: implement, but don't call REAL(malloc_stats)!
+}
+
+void * __sanitizer_calloc(uptr nmemb, uptr size) {
+  GET_MALLOC_STACK_TRACE;
+  if (UNLIKELY(!hwasan_inited))
+    // Hack: dlsym calls calloc before REAL(calloc) is retrieved from dlsym.
+    return AllocateFromLocalPool(nmemb * size);
+  return hwasan_calloc(nmemb, size, &stack);
+}
+
+void * __sanitizer_realloc(void *ptr, uptr size) {
+  GET_MALLOC_STACK_TRACE;
+  if (UNLIKELY(IsInDlsymAllocPool(ptr))) {
+    uptr offset = (uptr)ptr - (uptr)alloc_memory_for_dlsym;
+    uptr copy_size = Min(size, kDlsymAllocPoolSize - offset);
+    void *new_ptr;
+    if (UNLIKELY(!hwasan_inited)) {
+      new_ptr = AllocateFromLocalPool(copy_size);
+    } else {
+      copy_size = size;
+      new_ptr = hwasan_malloc(copy_size, &stack);
+    }
+    internal_memcpy(new_ptr, ptr, copy_size);
+    return new_ptr;
+  }
+  return hwasan_realloc(ptr, size, &stack);
+}
+
+void * __sanitizer_reallocarray(void *ptr, uptr nmemb, uptr size) {
+  GET_MALLOC_STACK_TRACE;
+  return hwasan_reallocarray(ptr, nmemb, size, &stack);
+}
+
+void * __sanitizer_malloc(uptr size) {
+  GET_MALLOC_STACK_TRACE;
+  if (UNLIKELY(!hwasan_init_is_running))
+    ENSURE_HWASAN_INITED();
+  if (UNLIKELY(!hwasan_inited))
+    // Hack: dlsym calls malloc before REAL(malloc) is retrieved from dlsym.
+    return AllocateFromLocalPool(size);
+  return hwasan_malloc(size, &stack);
+}
+
+#if HWASAN_WITH_INTERCEPTORS
+#define INTERCEPTOR_ALIAS(RET, FN, ARGS...)                                  \
+  extern "C" SANITIZER_INTERFACE_ATTRIBUTE RET WRAP(FN)(ARGS)                \
+      ALIAS("__sanitizer_" #FN);                                             \
+  extern "C" SANITIZER_INTERFACE_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE RET FN(  \
+      ARGS) ALIAS("__sanitizer_" #FN)
+
+INTERCEPTOR_ALIAS(int, posix_memalign, void **memptr, SIZE_T alignment,
+                  SIZE_T size);
+INTERCEPTOR_ALIAS(void *, aligned_alloc, SIZE_T alignment, SIZE_T size);
+INTERCEPTOR_ALIAS(void *, __libc_memalign, SIZE_T alignment, SIZE_T size);
+INTERCEPTOR_ALIAS(void *, valloc, SIZE_T size);
+INTERCEPTOR_ALIAS(void, free, void *ptr);
+INTERCEPTOR_ALIAS(uptr, malloc_usable_size, const void *ptr);
+INTERCEPTOR_ALIAS(void *, calloc, SIZE_T nmemb, SIZE_T size);
+INTERCEPTOR_ALIAS(void *, realloc, void *ptr, SIZE_T size);
+INTERCEPTOR_ALIAS(void *, reallocarray, void *ptr, SIZE_T nmemb, SIZE_T size);
+INTERCEPTOR_ALIAS(void *, malloc, SIZE_T size);
+
+#if !SANITIZER_FREEBSD && !SANITIZER_NETBSD
+INTERCEPTOR_ALIAS(void *, memalign, SIZE_T alignment, SIZE_T size);
+INTERCEPTOR_ALIAS(void *, pvalloc, SIZE_T size);
+INTERCEPTOR_ALIAS(void, cfree, void *ptr);
+INTERCEPTOR_ALIAS(__sanitizer_struct_mallinfo, mallinfo);
+INTERCEPTOR_ALIAS(int, mallopt, int cmd, int value);
+INTERCEPTOR_ALIAS(void, malloc_stats, void);
+#endif
+
+struct ThreadStartArg {
+  thread_callback_t callback;
+  void *param;
+};
+
+static void *HwasanThreadStartFunc(void *arg) {
+  __hwasan_thread_enter();
+  ThreadStartArg A = *reinterpret_cast<ThreadStartArg*>(arg);
+  UnmapOrDie(arg, GetPageSizeCached());
+  return A.callback(A.param);
+}
+
+INTERCEPTOR(int, pthread_create, void *th, void *attr, void *(*callback)(void*),
+            void * param) {
+  ScopedTaggingDisabler disabler;
+  ThreadStartArg *A = reinterpret_cast<ThreadStartArg *> (MmapOrDie(
+      GetPageSizeCached(), "pthread_create"));
+  *A = {callback, param};
+  int res = REAL(pthread_create)(UntagPtr(th), UntagPtr(attr),
+                                 &HwasanThreadStartFunc, A);
+  return res;
+}
+
+DEFINE_REAL(int, vfork)
+DECLARE_EXTERN_INTERCEPTOR_AND_WRAPPER(int, vfork)
+#endif // HWASAN_WITH_INTERCEPTORS
+
+#if HWASAN_WITH_INTERCEPTORS && defined(__aarch64__)
+// Get and/or change the set of blocked signals.
+extern "C" int sigprocmask(int __how, const __hw_sigset_t *__restrict __set,
+                           __hw_sigset_t *__restrict __oset);
+#define SIG_BLOCK 0
+#define SIG_SETMASK 2
+extern "C" int __sigjmp_save(__hw_sigjmp_buf env, int savemask) {
+  env[0].__mask_was_saved =
+      (savemask && sigprocmask(SIG_BLOCK, (__hw_sigset_t *)0,
+                               &env[0].__saved_mask) == 0);
+  return 0;
+}
+
+static void __attribute__((always_inline))
+InternalLongjmp(__hw_register_buf env, int retval) {
+  // Clear all memory tags on the stack between here and where we're going.
+  unsigned long long stack_pointer = env[13];
+  // The stack pointer should never be tagged, so we don't need to clear the
+  // tag for this function call.
+  __hwasan_handle_longjmp((void *)stack_pointer);
+
+  // Run code for handling a longjmp.
+  // Need to use a register that isn't going to be loaded from the environment
+  // buffer -- hence why we need to specify the register to use.
+  // Must implement this ourselves, since we don't know the order of registers
+  // in different libc implementations and many implementations mangle the
+  // stack pointer so we can't use it without knowing the demangling scheme.
+  register long int retval_tmp asm("x1") = retval;
+  register void *env_address asm("x0") = &env[0];
+  asm volatile("ldp	x19, x20, [%0, #0<<3];"
+               "ldp	x21, x22, [%0, #2<<3];"
+               "ldp	x23, x24, [%0, #4<<3];"
+               "ldp	x25, x26, [%0, #6<<3];"
+               "ldp	x27, x28, [%0, #8<<3];"
+               "ldp	x29, x30, [%0, #10<<3];"
+               "ldp	 d8,  d9, [%0, #14<<3];"
+               "ldp	d10, d11, [%0, #16<<3];"
+               "ldp	d12, d13, [%0, #18<<3];"
+               "ldp	d14, d15, [%0, #20<<3];"
+               "ldr	x5, [%0, #13<<3];"
+               "mov	sp, x5;"
+               // Return the value requested to return through arguments.
+               // This should be in x1 given what we requested above.
+               "cmp	%1, #0;"
+               "mov	x0, #1;"
+               "csel	x0, %1, x0, ne;"
+               "br	x30;"
+               : "+r"(env_address)
+               : "r"(retval_tmp));
+}
+
+INTERCEPTOR(void, siglongjmp, __hw_sigjmp_buf env, int val) {
+  if (env[0].__mask_was_saved)
+    // Restore the saved signal mask.
+    (void)sigprocmask(SIG_SETMASK, &env[0].__saved_mask,
+                      (__hw_sigset_t *)0);
+  InternalLongjmp(env[0].__jmpbuf, val);
+}
+
+// Required since glibc libpthread calls __libc_longjmp on pthread_exit, and
+// _setjmp on start_thread.  Hence we have to intercept the longjmp on
+// pthread_exit so the __hw_jmp_buf order matches.
+INTERCEPTOR(void, __libc_longjmp, __hw_jmp_buf env, int val) {
+  InternalLongjmp(env[0].__jmpbuf, val);
+}
+
+INTERCEPTOR(void, longjmp, __hw_jmp_buf env, int val) {
+  InternalLongjmp(env[0].__jmpbuf, val);
+}
+#undef SIG_BLOCK
+#undef SIG_SETMASK
+
+#endif // HWASAN_WITH_INTERCEPTORS && __aarch64__
+
+static void BeforeFork() {
+  StackDepotLockAll();
+}
+
+static void AfterFork() {
+  StackDepotUnlockAll();
+}
+
+INTERCEPTOR(int, fork, void) {
+  ENSURE_HWASAN_INITED();
+  BeforeFork();
+  int pid = REAL(fork)();
+  AfterFork();
+  return pid;
+}
+
+namespace __hwasan {
+
+int OnExit() {
+  // FIXME: ask frontend whether we need to return failure.
+  return 0;
+}
+
+} // namespace __hwasan
+
+namespace __hwasan {
+
+void InitializeInterceptors() {
+  static int inited = 0;
+  CHECK_EQ(inited, 0);
+
+  INTERCEPT_FUNCTION(fork);
+
+#if HWASAN_WITH_INTERCEPTORS
+#if defined(__linux__)
+  INTERCEPT_FUNCTION(vfork);
+#endif  // __linux__
+  INTERCEPT_FUNCTION(pthread_create);
+#endif
+
+  inited = 1;
+}
+} // namespace __hwasan
diff --git a/libsanitizer/hwasan/hwasan_interceptors_vfork.S b/libsanitizer/hwasan/hwasan_interceptors_vfork.S
new file mode 100644
index 00000000000..23d565936d8
--- /dev/null
+++ b/libsanitizer/hwasan/hwasan_interceptors_vfork.S
@@ -0,0 +1,11 @@
+#include "sanitizer_common/sanitizer_asm.h"
+
+#if defined(__linux__) && HWASAN_WITH_INTERCEPTORS
+#define COMMON_INTERCEPTOR_SPILL_AREA __hwasan_extra_spill_area
+#define COMMON_INTERCEPTOR_HANDLE_VFORK __hwasan_handle_vfork
+#include "sanitizer_common/sanitizer_common_interceptors_vfork_aarch64.inc.S"
+#include "sanitizer_common/sanitizer_common_interceptors_vfork_riscv64.inc.S"
+#include "sanitizer_common/sanitizer_common_interceptors_vfork_x86_64.inc.S"
+#endif
+
+NO_EXEC_STACK_DIRECTIVE
diff --git a/libsanitizer/hwasan/hwasan_interface_internal.h b/libsanitizer/hwasan/hwasan_interface_internal.h
new file mode 100644
index 00000000000..aedda317497
--- /dev/null
+++ b/libsanitizer/hwasan/hwasan_interface_internal.h
@@ -0,0 +1,227 @@
+//===-- hwasan_interface_internal.h -----------------------------*- C++ -*-===//
+//
+// 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 a part of HWAddressSanitizer.
+//
+// Private Hwasan interface header.
+//===----------------------------------------------------------------------===//
+
+#ifndef HWASAN_INTERFACE_INTERNAL_H
+#define HWASAN_INTERFACE_INTERNAL_H
+
+#include "sanitizer_common/sanitizer_internal_defs.h"
+#include "sanitizer_common/sanitizer_platform_limits_posix.h"
+#include <link.h>
+
+extern "C" {
+
+SANITIZER_INTERFACE_ATTRIBUTE
+void __hwasan_init_static();
+
+SANITIZER_INTERFACE_ATTRIBUTE
+void __hwasan_init();
+
+SANITIZER_INTERFACE_ATTRIBUTE
+void __hwasan_library_loaded(ElfW(Addr) base, const ElfW(Phdr) * phdr,
+                             ElfW(Half) phnum);
+
+SANITIZER_INTERFACE_ATTRIBUTE
+void __hwasan_library_unloaded(ElfW(Addr) base, const ElfW(Phdr) * phdr,
+                               ElfW(Half) phnum);
+
+using __sanitizer::uptr;
+using __sanitizer::sptr;
+using __sanitizer::uu64;
+using __sanitizer::uu32;
+using __sanitizer::uu16;
+using __sanitizer::u64;
+using __sanitizer::u32;
+using __sanitizer::u16;
+using __sanitizer::u8;
+
+SANITIZER_INTERFACE_ATTRIBUTE
+void __hwasan_init_frames(uptr, uptr);
+
+SANITIZER_INTERFACE_ATTRIBUTE
+extern uptr __hwasan_shadow_memory_dynamic_address;
+
+SANITIZER_INTERFACE_ATTRIBUTE
+void __hwasan_loadN(uptr, uptr);
+SANITIZER_INTERFACE_ATTRIBUTE
+void __hwasan_load1(uptr);
+SANITIZER_INTERFACE_ATTRIBUTE
+void __hwasan_load2(uptr);
+SANITIZER_INTERFACE_ATTRIBUTE
+void __hwasan_load4(uptr);
+SANITIZER_INTERFACE_ATTRIBUTE
+void __hwasan_load8(uptr);
+SANITIZER_INTERFACE_ATTRIBUTE
+void __hwasan_load16(uptr);
+
+SANITIZER_INTERFACE_ATTRIBUTE
+void __hwasan_loadN_noabort(uptr, uptr);
+SANITIZER_INTERFACE_ATTRIBUTE
+void __hwasan_load1_noabort(uptr);
+SANITIZER_INTERFACE_ATTRIBUTE
+void __hwasan_load2_noabort(uptr);
+SANITIZER_INTERFACE_ATTRIBUTE
+void __hwasan_load4_noabort(uptr);
+SANITIZER_INTERFACE_ATTRIBUTE
+void __hwasan_load8_noabort(uptr);
+SANITIZER_INTERFACE_ATTRIBUTE
+void __hwasan_load16_noabort(uptr);
+
+SANITIZER_INTERFACE_ATTRIBUTE
+void __hwasan_storeN(uptr, uptr);
+SANITIZER_INTERFACE_ATTRIBUTE
+void __hwasan_store1(uptr);
+SANITIZER_INTERFACE_ATTRIBUTE
+void __hwasan_store2(uptr);
+SANITIZER_INTERFACE_ATTRIBUTE
+void __hwasan_store4(uptr);
+SANITIZER_INTERFACE_ATTRIBUTE
+void __hwasan_store8(uptr);
+SANITIZER_INTERFACE_ATTRIBUTE
+void __hwasan_store16(uptr);
+
+SANITIZER_INTERFACE_ATTRIBUTE
+void __hwasan_storeN_noabort(uptr, uptr);
+SANITIZER_INTERFACE_ATTRIBUTE
+void __hwasan_store1_noabort(uptr);
+SANITIZER_INTERFACE_ATTRIBUTE
+void __hwasan_store2_noabort(uptr);
+SANITIZER_INTERFACE_ATTRIBUTE
+void __hwasan_store4_noabort(uptr);
+SANITIZER_INTERFACE_ATTRIBUTE
+void __hwasan_store8_noabort(uptr);
+SANITIZER_INTERFACE_ATTRIBUTE
+void __hwasan_store16_noabort(uptr);
+
+SANITIZER_INTERFACE_ATTRIBUTE
+void __hwasan_tag_memory(uptr p, u8 tag, uptr sz);
+
+SANITIZER_INTERFACE_ATTRIBUTE
+uptr __hwasan_tag_pointer(uptr p, u8 tag);
+
+SANITIZER_INTERFACE_ATTRIBUTE
+void __hwasan_tag_mismatch(uptr addr, u8 ts);
+
+SANITIZER_INTERFACE_ATTRIBUTE
+void __hwasan_tag_mismatch4(uptr addr, uptr access_info, uptr *registers_frame,
+                            size_t outsize);
+
+SANITIZER_INTERFACE_ATTRIBUTE
+u8 __hwasan_generate_tag();
+
+// Returns the offset of the first tag mismatch or -1 if the whole range is
+// good.
+SANITIZER_INTERFACE_ATTRIBUTE
+sptr __hwasan_test_shadow(const void *x, uptr size);
+
+SANITIZER_INTERFACE_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE
+/* OPTIONAL */ const char* __hwasan_default_options();
+
+SANITIZER_INTERFACE_ATTRIBUTE
+void __hwasan_print_shadow(const void *x, uptr size);
+
+SANITIZER_INTERFACE_ATTRIBUTE
+void __hwasan_handle_longjmp(const void *sp_dst);
+
+SANITIZER_INTERFACE_ATTRIBUTE
+void __hwasan_handle_vfork(const void *sp_dst);
+
+SANITIZER_INTERFACE_ATTRIBUTE
+u16 __sanitizer_unaligned_load16(const uu16 *p);
+
+SANITIZER_INTERFACE_ATTRIBUTE
+u32 __sanitizer_unaligned_load32(const uu32 *p);
+
+SANITIZER_INTERFACE_ATTRIBUTE
+u64 __sanitizer_unaligned_load64(const uu64 *p);
+
+SANITIZER_INTERFACE_ATTRIBUTE
+void __sanitizer_unaligned_store16(uu16 *p, u16 x);
+
+SANITIZER_INTERFACE_ATTRIBUTE
+void __sanitizer_unaligned_store32(uu32 *p, u32 x);
+
+SANITIZER_INTERFACE_ATTRIBUTE
+void __sanitizer_unaligned_store64(uu64 *p, u64 x);
+
+SANITIZER_INTERFACE_ATTRIBUTE
+void __hwasan_enable_allocator_tagging();
+
+SANITIZER_INTERFACE_ATTRIBUTE
+void __hwasan_disable_allocator_tagging();
+
+SANITIZER_INTERFACE_ATTRIBUTE
+void __hwasan_thread_enter();
+
+SANITIZER_INTERFACE_ATTRIBUTE
+void __hwasan_thread_exit();
+
+SANITIZER_INTERFACE_ATTRIBUTE
+void __hwasan_print_memory_usage();
+
+SANITIZER_INTERFACE_ATTRIBUTE
+int __sanitizer_posix_memalign(void **memptr, uptr alignment, uptr size);
+
+SANITIZER_INTERFACE_ATTRIBUTE
+void * __sanitizer_memalign(uptr alignment, uptr size);
+
+SANITIZER_INTERFACE_ATTRIBUTE
+void * __sanitizer_aligned_alloc(uptr alignment, uptr size);
+
+SANITIZER_INTERFACE_ATTRIBUTE
+void * __sanitizer___libc_memalign(uptr alignment, uptr size);
+
+SANITIZER_INTERFACE_ATTRIBUTE
+void * __sanitizer_valloc(uptr size);
+
+SANITIZER_INTERFACE_ATTRIBUTE
+void * __sanitizer_pvalloc(uptr size);
+
+SANITIZER_INTERFACE_ATTRIBUTE
+void __sanitizer_free(void *ptr);
+
+SANITIZER_INTERFACE_ATTRIBUTE
+void __sanitizer_cfree(void *ptr);
+
+SANITIZER_INTERFACE_ATTRIBUTE
+uptr __sanitizer_malloc_usable_size(const void *ptr);
+
+SANITIZER_INTERFACE_ATTRIBUTE
+__hwasan::__sanitizer_struct_mallinfo __sanitizer_mallinfo();
+
+SANITIZER_INTERFACE_ATTRIBUTE
+int __sanitizer_mallopt(int cmd, int value);
+
+SANITIZER_INTERFACE_ATTRIBUTE
+void __sanitizer_malloc_stats(void);
+
+SANITIZER_INTERFACE_ATTRIBUTE
+void * __sanitizer_calloc(uptr nmemb, uptr size);
+
+SANITIZER_INTERFACE_ATTRIBUTE
+void * __sanitizer_realloc(void *ptr, uptr size);
+
+SANITIZER_INTERFACE_ATTRIBUTE
+void * __sanitizer_reallocarray(void *ptr, uptr nmemb, uptr size);
+
+SANITIZER_INTERFACE_ATTRIBUTE
+void * __sanitizer_malloc(uptr size);
+
+SANITIZER_INTERFACE_ATTRIBUTE
+void *__hwasan_memcpy(void *dst, const void *src, uptr size);
+SANITIZER_INTERFACE_ATTRIBUTE
+void *__hwasan_memset(void *s, int c, uptr n);
+SANITIZER_INTERFACE_ATTRIBUTE
+void *__hwasan_memmove(void *dest, const void *src, uptr n);
+}  // extern "C"
+
+#endif  // HWASAN_INTERFACE_INTERNAL_H
diff --git a/libsanitizer/hwasan/hwasan_linux.cpp b/libsanitizer/hwasan/hwasan_linux.cpp
new file mode 100644
index 00000000000..e99926d355c
--- /dev/null
+++ b/libsanitizer/hwasan/hwasan_linux.cpp
@@ -0,0 +1,455 @@
+//===-- hwasan_linux.cpp ----------------------------------------*- C++ -*-===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This file is a part of HWAddressSanitizer and contains Linux-, NetBSD- and
+/// FreeBSD-specific code.
+///
+//===----------------------------------------------------------------------===//
+
+#include "sanitizer_common/sanitizer_platform.h"
+#if SANITIZER_FREEBSD || SANITIZER_LINUX || SANITIZER_NETBSD
+
+#include "hwasan.h"
+#include "hwasan_dynamic_shadow.h"
+#include "hwasan_interface_internal.h"
+#include "hwasan_mapping.h"
+#include "hwasan_report.h"
+#include "hwasan_thread.h"
+#include "hwasan_thread_list.h"
+
+#include <dlfcn.h>
+#include <elf.h>
+#include <link.h>
+#include <pthread.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/resource.h>
+#include <sys/time.h>
+#include <unistd.h>
+#include <unwind.h>
+#include <sys/prctl.h>
+#include <errno.h>
+
+#include "sanitizer_common/sanitizer_common.h"
+#include "sanitizer_common/sanitizer_procmaps.h"
+
+// Configurations of HWASAN_WITH_INTERCEPTORS and SANITIZER_ANDROID.
+//
+// HWASAN_WITH_INTERCEPTORS=OFF, SANITIZER_ANDROID=OFF
+//   Not currently tested.
+// HWASAN_WITH_INTERCEPTORS=OFF, SANITIZER_ANDROID=ON
+//   Integration tests downstream exist.
+// HWASAN_WITH_INTERCEPTORS=ON, SANITIZER_ANDROID=OFF
+//    Tested with check-hwasan on x86_64-linux.
+// HWASAN_WITH_INTERCEPTORS=ON, SANITIZER_ANDROID=ON
+//    Tested with check-hwasan on aarch64-linux-android.
+#if !SANITIZER_ANDROID
+SANITIZER_INTERFACE_ATTRIBUTE
+THREADLOCAL uptr __hwasan_tls;
+#endif
+
+namespace __hwasan {
+
+// With the zero shadow base we can not actually map pages starting from 0.
+// This constant is somewhat arbitrary.
+constexpr uptr kZeroBaseShadowStart = 0;
+constexpr uptr kZeroBaseMaxShadowStart = 1 << 18;
+
+static void ProtectGap(uptr addr, uptr size) {
+  __sanitizer::ProtectGap(addr, size, kZeroBaseShadowStart,
+                          kZeroBaseMaxShadowStart);
+}
+
+uptr kLowMemStart;
+uptr kLowMemEnd;
+uptr kLowShadowEnd;
+uptr kLowShadowStart;
+uptr kHighShadowStart;
+uptr kHighShadowEnd;
+uptr kHighMemStart;
+uptr kHighMemEnd;
+
+static void PrintRange(uptr start, uptr end, const char *name) {
+  Printf("|| [%p, %p] || %.*s ||\n", (void *)start, (void *)end, 10, name);
+}
+
+static void PrintAddressSpaceLayout() {
+  PrintRange(kHighMemStart, kHighMemEnd, "HighMem");
+  if (kHighShadowEnd + 1 < kHighMemStart)
+    PrintRange(kHighShadowEnd + 1, kHighMemStart - 1, "ShadowGap");
+  else
+    CHECK_EQ(kHighShadowEnd + 1, kHighMemStart);
+  PrintRange(kHighShadowStart, kHighShadowEnd, "HighShadow");
+  if (kLowShadowEnd + 1 < kHighShadowStart)
+    PrintRange(kLowShadowEnd + 1, kHighShadowStart - 1, "ShadowGap");
+  else
+    CHECK_EQ(kLowMemEnd + 1, kHighShadowStart);
+  PrintRange(kLowShadowStart, kLowShadowEnd, "LowShadow");
+  if (kLowMemEnd + 1 < kLowShadowStart)
+    PrintRange(kLowMemEnd + 1, kLowShadowStart - 1, "ShadowGap");
+  else
+    CHECK_EQ(kLowMemEnd + 1, kLowShadowStart);
+  PrintRange(kLowMemStart, kLowMemEnd, "LowMem");
+  CHECK_EQ(0, kLowMemStart);
+}
+
+static uptr GetHighMemEnd() {
+  // HighMem covers the upper part of the address space.
+  uptr max_address = GetMaxUserVirtualAddress();
+  // Adjust max address to make sure that kHighMemEnd and kHighMemStart are
+  // properly aligned:
+  max_address |= (GetMmapGranularity() << kShadowScale) - 1;
+  return max_address;
+}
+
+static void InitializeShadowBaseAddress(uptr shadow_size_bytes) {
+  __hwasan_shadow_memory_dynamic_address =
+      FindDynamicShadowStart(shadow_size_bytes);
+}
+
+void InitPrctl() {
+#define PR_SET_TAGGED_ADDR_CTRL 55
+#define PR_GET_TAGGED_ADDR_CTRL 56
+#define PR_TAGGED_ADDR_ENABLE (1UL << 0)
+  // Check we're running on a kernel that can use the tagged address ABI.
+  if (internal_prctl(PR_GET_TAGGED_ADDR_CTRL, 0, 0, 0, 0) == (uptr)-1 &&
+      errno == EINVAL) {
+#if SANITIZER_ANDROID
+    // Some older Android kernels have the tagged pointer ABI on
+    // unconditionally, and hence don't have the tagged-addr prctl while still
+    // allow the ABI.
+    // If targeting Android and the prctl is not around we assume this is the
+    // case.
+    return;
+#else
+    Printf(
+        "FATAL: "
+        "HWAddressSanitizer requires a kernel with tagged address ABI.\n");
+    Die();
+#endif
+  }
+
+  // Turn on the tagged address ABI.
+  if (internal_prctl(PR_SET_TAGGED_ADDR_CTRL, PR_TAGGED_ADDR_ENABLE, 0, 0, 0) ==
+          (uptr)-1 ||
+      !internal_prctl(PR_GET_TAGGED_ADDR_CTRL, 0, 0, 0, 0)) {
+    Printf(
+        "FATAL: HWAddressSanitizer failed to enable tagged address syscall "
+        "ABI.\nSuggest check `sysctl abi.tagged_addr_disabled` "
+        "configuration.\n");
+    Die();
+  }
+#undef PR_SET_TAGGED_ADDR_CTRL
+#undef PR_GET_TAGGED_ADDR_CTRL
+#undef PR_TAGGED_ADDR_ENABLE
+}
+
+bool InitShadow() {
+  // Define the entire memory range.
+  kHighMemEnd = GetHighMemEnd();
+
+  // Determine shadow memory base offset.
+  InitializeShadowBaseAddress(MemToShadowSize(kHighMemEnd));
+
+  // Place the low memory first.
+  kLowMemEnd = __hwasan_shadow_memory_dynamic_address - 1;
+  kLowMemStart = 0;
+
+  // Define the low shadow based on the already placed low memory.
+  kLowShadowEnd = MemToShadow(kLowMemEnd);
+  kLowShadowStart = __hwasan_shadow_memory_dynamic_address;
+
+  // High shadow takes whatever memory is left up there (making sure it is not
+  // interfering with low memory in the fixed case).
+  kHighShadowEnd = MemToShadow(kHighMemEnd);
+  kHighShadowStart = Max(kLowMemEnd, MemToShadow(kHighShadowEnd)) + 1;
+
+  // High memory starts where allocated shadow allows.
+  kHighMemStart = ShadowToMem(kHighShadowStart);
+
+  // Check the sanity of the defined memory ranges (there might be gaps).
+  CHECK_EQ(kHighMemStart % GetMmapGranularity(), 0);
+  CHECK_GT(kHighMemStart, kHighShadowEnd);
+  CHECK_GT(kHighShadowEnd, kHighShadowStart);
+  CHECK_GT(kHighShadowStart, kLowMemEnd);
+  CHECK_GT(kLowMemEnd, kLowMemStart);
+  CHECK_GT(kLowShadowEnd, kLowShadowStart);
+  CHECK_GT(kLowShadowStart, kLowMemEnd);
+
+  if (Verbosity())
+    PrintAddressSpaceLayout();
+
+  // Reserve shadow memory.
+  ReserveShadowMemoryRange(kLowShadowStart, kLowShadowEnd, "low shadow");
+  ReserveShadowMemoryRange(kHighShadowStart, kHighShadowEnd, "high shadow");
+
+  // Protect all the gaps.
+  ProtectGap(0, Min(kLowMemStart, kLowShadowStart));
+  if (kLowMemEnd + 1 < kLowShadowStart)
+    ProtectGap(kLowMemEnd + 1, kLowShadowStart - kLowMemEnd - 1);
+  if (kLowShadowEnd + 1 < kHighShadowStart)
+    ProtectGap(kLowShadowEnd + 1, kHighShadowStart - kLowShadowEnd - 1);
+  if (kHighShadowEnd + 1 < kHighMemStart)
+    ProtectGap(kHighShadowEnd + 1, kHighMemStart - kHighShadowEnd - 1);
+
+  return true;
+}
+
+void InitThreads() {
+  CHECK(__hwasan_shadow_memory_dynamic_address);
+  uptr guard_page_size = GetMmapGranularity();
+  uptr thread_space_start =
+      __hwasan_shadow_memory_dynamic_address - (1ULL << kShadowBaseAlignment);
+  uptr thread_space_end =
+      __hwasan_shadow_memory_dynamic_address - guard_page_size;
+  ReserveShadowMemoryRange(thread_space_start, thread_space_end - 1,
+                           "hwasan threads", /*madvise_shadow*/ false);
+  ProtectGap(thread_space_end,
+             __hwasan_shadow_memory_dynamic_address - thread_space_end);
+  InitThreadList(thread_space_start, thread_space_end - thread_space_start);
+}
+
+bool MemIsApp(uptr p) {
+  CHECK(GetTagFromPointer(p) == 0);
+  return p >= kHighMemStart || (p >= kLowMemStart && p <= kLowMemEnd);
+}
+
+static void HwasanAtExit(void) {
+  if (common_flags()->print_module_map)
+    DumpProcessMap();
+  if (flags()->print_stats && (flags()->atexit || hwasan_report_count > 0))
+    ReportStats();
+  if (hwasan_report_count > 0) {
+    // ReportAtExitStatistics();
+    if (common_flags()->exitcode)
+      internal__exit(common_flags()->exitcode);
+  }
+}
+
+void InstallAtExitHandler() {
+  atexit(HwasanAtExit);
+}
+
+// ---------------------- TSD ---------------- {{{1
+
+extern "C" void __hwasan_thread_enter() {
+  hwasanThreadList().CreateCurrentThread()->InitRandomState();
+}
+
+extern "C" void __hwasan_thread_exit() {
+  Thread *t = GetCurrentThread();
+  // Make sure that signal handler can not see a stale current thread pointer.
+  atomic_signal_fence(memory_order_seq_cst);
+  if (t)
+    hwasanThreadList().ReleaseThread(t);
+}
+
+#if HWASAN_WITH_INTERCEPTORS
+static pthread_key_t tsd_key;
+static bool tsd_key_inited = false;
+
+void HwasanTSDThreadInit() {
+  if (tsd_key_inited)
+    CHECK_EQ(0, pthread_setspecific(tsd_key,
+                                    (void *)GetPthreadDestructorIterations()));
+}
+
+void HwasanTSDDtor(void *tsd) {
+  uptr iterations = (uptr)tsd;
+  if (iterations > 1) {
+    CHECK_EQ(0, pthread_setspecific(tsd_key, (void *)(iterations - 1)));
+    return;
+  }
+  __hwasan_thread_exit();
+}
+
+void HwasanTSDInit() {
+  CHECK(!tsd_key_inited);
+  tsd_key_inited = true;
+  CHECK_EQ(0, pthread_key_create(&tsd_key, HwasanTSDDtor));
+}
+#else
+void HwasanTSDInit() {}
+void HwasanTSDThreadInit() {}
+#endif
+
+#if SANITIZER_ANDROID
+uptr *GetCurrentThreadLongPtr() {
+  return (uptr *)get_android_tls_ptr();
+}
+#else
+uptr *GetCurrentThreadLongPtr() {
+  return &__hwasan_tls;
+}
+#endif
+
+#if SANITIZER_ANDROID
+void AndroidTestTlsSlot() {
+  uptr kMagicValue = 0x010203040A0B0C0D;
+  uptr *tls_ptr = GetCurrentThreadLongPtr();
+  uptr old_value = *tls_ptr;
+  *tls_ptr = kMagicValue;
+  dlerror();
+  if (*(uptr *)get_android_tls_ptr() != kMagicValue) {
+    Printf(
+        "ERROR: Incompatible version of Android: TLS_SLOT_SANITIZER(6) is used "
+        "for dlerror().\n");
+    Die();
+  }
+  *tls_ptr = old_value;
+}
+#else
+void AndroidTestTlsSlot() {}
+#endif
+
+Thread *GetCurrentThread() {
+  uptr *ThreadLongPtr = GetCurrentThreadLongPtr();
+  if (UNLIKELY(*ThreadLongPtr == 0))
+    return nullptr;
+  auto *R = (StackAllocationsRingBuffer *)ThreadLongPtr;
+  return hwasanThreadList().GetThreadByBufferAddress((uptr)R->Next());
+}
+
+struct AccessInfo {
+  uptr addr;
+  uptr size;
+  bool is_store;
+  bool is_load;
+  bool recover;
+};
+
+static AccessInfo GetAccessInfo(siginfo_t *info, ucontext_t *uc) {
+  // Access type is passed in a platform dependent way (see below) and encoded
+  // as 0xXY, where X&1 is 1 for store, 0 for load, and X&2 is 1 if the error is
+  // recoverable. Valid values of Y are 0 to 4, which are interpreted as
+  // log2(access_size), and 0xF, which means that access size is passed via
+  // platform dependent register (see below).
+#if defined(__aarch64__)
+  // Access type is encoded in BRK immediate as 0x900 + 0xXY. For Y == 0xF,
+  // access size is stored in X1 register. Access address is always in X0
+  // register.
+  uptr pc = (uptr)info->si_addr;
+  const unsigned code = ((*(u32 *)pc) >> 5) & 0xffff;
+  if ((code & 0xff00) != 0x900)
+    return AccessInfo{}; // Not ours.
+
+  const bool is_store = code & 0x10;
+  const bool recover = code & 0x20;
+  const uptr addr = uc->uc_mcontext.regs[0];
+  const unsigned size_log = code & 0xf;
+  if (size_log > 4 && size_log != 0xf)
+    return AccessInfo{}; // Not ours.
+  const uptr size = size_log == 0xf ? uc->uc_mcontext.regs[1] : 1U << size_log;
+
+#elif defined(__x86_64__)
+  // Access type is encoded in the instruction following INT3 as
+  // NOP DWORD ptr [EAX + 0x40 + 0xXY]. For Y == 0xF, access size is stored in
+  // RSI register. Access address is always in RDI register.
+  uptr pc = (uptr)uc->uc_mcontext.gregs[REG_RIP];
+  uint8_t *nop = (uint8_t*)pc;
+  if (*nop != 0x0f || *(nop + 1) != 0x1f || *(nop + 2) != 0x40  ||
+      *(nop + 3) < 0x40)
+    return AccessInfo{}; // Not ours.
+  const unsigned code = *(nop + 3);
+
+  const bool is_store = code & 0x10;
+  const bool recover = code & 0x20;
+  const uptr addr = uc->uc_mcontext.gregs[REG_RDI];
+  const unsigned size_log = code & 0xf;
+  if (size_log > 4 && size_log != 0xf)
+    return AccessInfo{}; // Not ours.
+  const uptr size =
+      size_log == 0xf ? uc->uc_mcontext.gregs[REG_RSI] : 1U << size_log;
+
+#else
+# error Unsupported architecture
+#endif
+
+  return AccessInfo{addr, size, is_store, !is_store, recover};
+}
+
+static void HandleTagMismatch(AccessInfo ai, uptr pc, uptr frame,
+                              ucontext_t *uc, uptr *registers_frame = nullptr) {
+  InternalMmapVector<BufferedStackTrace> stack_buffer(1);
+  BufferedStackTrace *stack = stack_buffer.data();
+  stack->Reset();
+  stack->Unwind(pc, frame, uc, common_flags()->fast_unwind_on_fatal);
+
+  // The second stack frame contains the failure __hwasan_check function, as
+  // we have a stack frame for the registers saved in __hwasan_tag_mismatch that
+  // we wish to ignore. This (currently) only occurs on AArch64, as x64
+  // implementations use SIGTRAP to implement the failure, and thus do not go
+  // through the stack saver.
+  if (registers_frame && stack->trace && stack->size > 0) {
+    stack->trace++;
+    stack->size--;
+  }
+
+  bool fatal = flags()->halt_on_error || !ai.recover;
+  ReportTagMismatch(stack, ai.addr, ai.size, ai.is_store, fatal,
+                    registers_frame);
+}
+
+static bool HwasanOnSIGTRAP(int signo, siginfo_t *info, ucontext_t *uc) {
+  AccessInfo ai = GetAccessInfo(info, uc);
+  if (!ai.is_store && !ai.is_load)
+    return false;
+
+  SignalContext sig{info, uc};
+  HandleTagMismatch(ai, StackTrace::GetNextInstructionPc(sig.pc), sig.bp, uc);
+
+#if defined(__aarch64__)
+  uc->uc_mcontext.pc += 4;
+#elif defined(__x86_64__)
+#else
+# error Unsupported architecture
+#endif
+  return true;
+}
+
+static void OnStackUnwind(const SignalContext &sig, const void *,
+                          BufferedStackTrace *stack) {
+  stack->Unwind(StackTrace::GetNextInstructionPc(sig.pc), sig.bp, sig.context,
+                common_flags()->fast_unwind_on_fatal);
+}
+
+void HwasanOnDeadlySignal(int signo, void *info, void *context) {
+  // Probably a tag mismatch.
+  if (signo == SIGTRAP)
+    if (HwasanOnSIGTRAP(signo, (siginfo_t *)info, (ucontext_t*)context))
+      return;
+
+  HandleDeadlySignal(info, context, GetTid(), &OnStackUnwind, nullptr);
+}
+
+
+} // namespace __hwasan
+
+// Entry point for interoperability between __hwasan_tag_mismatch (ASM) and the
+// rest of the mismatch handling code (C++).
+void __hwasan_tag_mismatch4(uptr addr, uptr access_info, uptr *registers_frame,
+                            size_t outsize) {
+  __hwasan::AccessInfo ai;
+  ai.is_store = access_info & 0x10;
+  ai.is_load = !ai.is_store;
+  ai.recover = access_info & 0x20;
+  ai.addr = addr;
+  if ((access_info & 0xf) == 0xf)
+    ai.size = outsize;
+  else
+    ai.size = 1 << (access_info & 0xf);
+
+  __hwasan::HandleTagMismatch(ai, (uptr)__builtin_return_address(0),
+                              (uptr)__builtin_frame_address(0), nullptr,
+                              registers_frame);
+  __builtin_unreachable();
+}
+
+#endif // SANITIZER_FREEBSD || SANITIZER_LINUX || SANITIZER_NETBSD
diff --git a/libsanitizer/hwasan/hwasan_malloc_bisect.h b/libsanitizer/hwasan/hwasan_malloc_bisect.h
new file mode 100644
index 00000000000..7d134e8c4b7
--- /dev/null
+++ b/libsanitizer/hwasan/hwasan_malloc_bisect.h
@@ -0,0 +1,50 @@
+//===-- hwasan_malloc_bisect.h ----------------------------------*- C++ -*-===//
+//
+// 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 a part of HWAddressSanitizer.
+//
+//===----------------------------------------------------------------------===//
+
+#include "sanitizer_common/sanitizer_hash.h"
+#include "hwasan.h"
+
+namespace __hwasan {
+
+static u32 malloc_hash(StackTrace *stack, uptr orig_size) {
+  uptr len = Min(stack->size, (unsigned)7);
+  MurMur2HashBuilder H(len);
+  H.add(orig_size);
+  // Start with frame #1 to skip __sanitizer_malloc frame, which is
+  // (a) almost always the same (well, could be operator new or new[])
+  // (b) can change hashes when compiler-rt is rebuilt, invalidating previous
+  // bisection results.
+  // Because of ASLR, use only offset inside the page.
+  for (uptr i = 1; i < len; ++i) H.add(((u32)stack->trace[i]) & 0xFFF);
+  return H.get();
+}
+
+static inline bool malloc_bisect(StackTrace *stack, uptr orig_size) {
+  uptr left = flags()->malloc_bisect_left;
+  uptr right = flags()->malloc_bisect_right;
+  if (LIKELY(left == 0 && right == 0))
+    return true;
+  if (!stack)
+    return true;
+  // Allow malloc_bisect_right > (u32)(-1) to avoid spelling the latter in
+  // decimal.
+  uptr h = (uptr)malloc_hash(stack, orig_size);
+  if (h < left || h > right)
+    return false;
+  if (flags()->malloc_bisect_dump) {
+    Printf("[alloc] %u %zu\n", h, orig_size);
+    stack->Print();
+  }
+  return true;
+}
+
+}  // namespace __hwasan
diff --git a/libsanitizer/hwasan/hwasan_mapping.h b/libsanitizer/hwasan/hwasan_mapping.h
new file mode 100644
index 00000000000..c149687bdfa
--- /dev/null
+++ b/libsanitizer/hwasan/hwasan_mapping.h
@@ -0,0 +1,66 @@
+//===-- hwasan_mapping.h ----------------------------------------*- C++ -*-===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This file is a part of HWAddressSanitizer and defines memory mapping.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef HWASAN_MAPPING_H
+#define HWASAN_MAPPING_H
+
+#include "sanitizer_common/sanitizer_internal_defs.h"
+#include "hwasan_interface_internal.h"
+
+// Typical mapping on Linux/x86_64:
+// with dynamic shadow mapped at [0x770d59f40000, 0x7f0d59f40000]:
+// || [0x7f0d59f40000, 0x7fffffffffff] || HighMem    ||
+// || [0x7efe2f934000, 0x7f0d59f3ffff] || HighShadow ||
+// || [0x7e7e2f934000, 0x7efe2f933fff] || ShadowGap  ||
+// || [0x770d59f40000, 0x7e7e2f933fff] || LowShadow  ||
+// || [0x000000000000, 0x770d59f3ffff] || LowMem     ||
+
+// Typical mapping on Android/AArch64
+// with dynamic shadow mapped: [0x007477480000, 0x007c77480000]:
+// || [0x007c77480000, 0x007fffffffff] || HighMem    ||
+// || [0x007c3ebc8000, 0x007c7747ffff] || HighShadow ||
+// || [0x007bbebc8000, 0x007c3ebc7fff] || ShadowGap  ||
+// || [0x007477480000, 0x007bbebc7fff] || LowShadow  ||
+// || [0x000000000000, 0x00747747ffff] || LowMem     ||
+
+// Reasonable values are 4 (for 1/16th shadow) and 6 (for 1/64th).
+constexpr uptr kShadowScale = 4;
+constexpr uptr kShadowAlignment = 1ULL << kShadowScale;
+
+namespace __hwasan {
+
+extern uptr kLowMemStart;
+extern uptr kLowMemEnd;
+extern uptr kLowShadowEnd;
+extern uptr kLowShadowStart;
+extern uptr kHighShadowStart;
+extern uptr kHighShadowEnd;
+extern uptr kHighMemStart;
+extern uptr kHighMemEnd;
+
+inline uptr MemToShadow(uptr untagged_addr) {
+  return (untagged_addr >> kShadowScale) +
+         __hwasan_shadow_memory_dynamic_address;
+}
+inline uptr ShadowToMem(uptr shadow_addr) {
+  return (shadow_addr - __hwasan_shadow_memory_dynamic_address) << kShadowScale;
+}
+inline uptr MemToShadowSize(uptr size) {
+  return size >> kShadowScale;
+}
+
+bool MemIsApp(uptr p);
+
+}  // namespace __hwasan
+
+#endif  // HWASAN_MAPPING_H
diff --git a/libsanitizer/hwasan/hwasan_memintrinsics.cpp b/libsanitizer/hwasan/hwasan_memintrinsics.cpp
new file mode 100644
index 00000000000..e82d77a1bc1
--- /dev/null
+++ b/libsanitizer/hwasan/hwasan_memintrinsics.cpp
@@ -0,0 +1,44 @@
+//===-- hwasan_memintrinsics.cpp --------------------------------*- C++ -*-===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This file is a part of HWAddressSanitizer and contains HWASAN versions of
+/// memset, memcpy and memmove
+///
+//===----------------------------------------------------------------------===//
+
+#include <string.h>
+#include "hwasan.h"
+#include "hwasan_checks.h"
+#include "hwasan_flags.h"
+#include "hwasan_interface_internal.h"
+#include "sanitizer_common/sanitizer_libc.h"
+
+using namespace __hwasan;
+
+void *__hwasan_memset(void *block, int c, uptr size) {
+  CheckAddressSized<ErrorAction::Recover, AccessType::Store>(
+      reinterpret_cast<uptr>(block), size);
+  return memset(UntagPtr(block), c, size);
+}
+
+void *__hwasan_memcpy(void *to, const void *from, uptr size) {
+  CheckAddressSized<ErrorAction::Recover, AccessType::Store>(
+      reinterpret_cast<uptr>(to), size);
+  CheckAddressSized<ErrorAction::Recover, AccessType::Load>(
+      reinterpret_cast<uptr>(from), size);
+  return memcpy(UntagPtr(to), UntagPtr(from), size);
+}
+
+void *__hwasan_memmove(void *to, const void *from, uptr size) {
+  CheckAddressSized<ErrorAction::Recover, AccessType::Store>(
+      reinterpret_cast<uptr>(to), size);
+  CheckAddressSized<ErrorAction::Recover, AccessType::Load>(
+      reinterpret_cast<uptr>(from), size);
+  return memmove(UntagPtr(to), UntagPtr(from), size);
+}
diff --git a/libsanitizer/hwasan/hwasan_new_delete.cpp b/libsanitizer/hwasan/hwasan_new_delete.cpp
new file mode 100644
index 00000000000..8d01d3944f2
--- /dev/null
+++ b/libsanitizer/hwasan/hwasan_new_delete.cpp
@@ -0,0 +1,81 @@
+//===-- hwasan_new_delete.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 a part of HWAddressSanitizer.
+//
+// Interceptors for operators new and delete.
+//===----------------------------------------------------------------------===//
+
+#include "hwasan.h"
+#include "interception/interception.h"
+#include "sanitizer_common/sanitizer_allocator.h"
+#include "sanitizer_common/sanitizer_allocator_report.h"
+
+#include <stddef.h>
+#include <stdlib.h>
+
+#if HWASAN_REPLACE_OPERATORS_NEW_AND_DELETE
+
+// TODO(alekseys): throw std::bad_alloc instead of dying on OOM.
+#define OPERATOR_NEW_BODY(nothrow) \
+  GET_MALLOC_STACK_TRACE; \
+  void *res = hwasan_malloc(size, &stack);\
+  if (!nothrow && UNLIKELY(!res)) ReportOutOfMemory(size, &stack);\
+  return res
+
+#define OPERATOR_DELETE_BODY \
+  GET_MALLOC_STACK_TRACE; \
+  if (ptr) hwasan_free(ptr, &stack)
+
+#elif defined(__ANDROID__)
+
+// We don't actually want to intercept operator new and delete on Android, but
+// since we previously released a runtime that intercepted these functions,
+// removing the interceptors would break ABI. Therefore we simply forward to
+// malloc and free.
+#define OPERATOR_NEW_BODY(nothrow) return malloc(size)
+#define OPERATOR_DELETE_BODY free(ptr)
+
+#endif
+
+#ifdef OPERATOR_NEW_BODY
+
+using namespace __hwasan;
+
+// Fake std::nothrow_t to avoid including <new>.
+namespace std {
+  struct nothrow_t {};
+}  // namespace std
+
+
+
+INTERCEPTOR_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE
+void *operator new(size_t size) { OPERATOR_NEW_BODY(false /*nothrow*/); }
+INTERCEPTOR_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE
+void *operator new[](size_t size) { OPERATOR_NEW_BODY(false /*nothrow*/); }
+INTERCEPTOR_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE
+void *operator new(size_t size, std::nothrow_t const&) {
+  OPERATOR_NEW_BODY(true /*nothrow*/);
+}
+INTERCEPTOR_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE
+void *operator new[](size_t size, std::nothrow_t const&) {
+  OPERATOR_NEW_BODY(true /*nothrow*/);
+}
+
+INTERCEPTOR_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE
+void operator delete(void *ptr) NOEXCEPT { OPERATOR_DELETE_BODY; }
+INTERCEPTOR_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE
+void operator delete[](void *ptr) NOEXCEPT { OPERATOR_DELETE_BODY; }
+INTERCEPTOR_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE
+void operator delete(void *ptr, std::nothrow_t const&) { OPERATOR_DELETE_BODY; }
+INTERCEPTOR_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE
+void operator delete[](void *ptr, std::nothrow_t const&) {
+  OPERATOR_DELETE_BODY;
+}
+
+#endif // OPERATOR_NEW_BODY
diff --git a/libsanitizer/hwasan/hwasan_poisoning.cpp b/libsanitizer/hwasan/hwasan_poisoning.cpp
new file mode 100644
index 00000000000..2a0816428e7
--- /dev/null
+++ b/libsanitizer/hwasan/hwasan_poisoning.cpp
@@ -0,0 +1,52 @@
+//===-- hwasan_poisoning.cpp ------------------------------------*- C++ -*-===//
+//
+// 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 a part of HWAddressSanitizer.
+//
+//===----------------------------------------------------------------------===//
+
+#include "hwasan_poisoning.h"
+
+#include "hwasan_mapping.h"
+#include "interception/interception.h"
+#include "sanitizer_common/sanitizer_common.h"
+#include "sanitizer_common/sanitizer_linux.h"
+
+namespace __hwasan {
+
+uptr TagMemoryAligned(uptr p, uptr size, tag_t tag) {
+  CHECK(IsAligned(p, kShadowAlignment));
+  CHECK(IsAligned(size, kShadowAlignment));
+  uptr shadow_start = MemToShadow(p);
+  uptr shadow_size = MemToShadowSize(size);
+
+  uptr page_size = GetPageSizeCached();
+  uptr page_start = RoundUpTo(shadow_start, page_size);
+  uptr page_end = RoundDownTo(shadow_start + shadow_size, page_size);
+  uptr threshold = common_flags()->clear_shadow_mmap_threshold;
+  if (SANITIZER_LINUX &&
+      UNLIKELY(page_end >= page_start + threshold && tag == 0)) {
+    internal_memset((void *)shadow_start, tag, page_start - shadow_start);
+    internal_memset((void *)page_end, tag,
+                    shadow_start + shadow_size - page_end);
+    // For an anonymous private mapping MADV_DONTNEED will return a zero page on
+    // Linux.
+    ReleaseMemoryPagesToOSAndZeroFill(page_start, page_end);
+  } else {
+    internal_memset((void *)shadow_start, tag, shadow_size);
+  }
+  return AddTagToPointer(p, tag);
+}
+
+uptr TagMemory(uptr p, uptr size, tag_t tag) {
+  uptr start = RoundDownTo(p, kShadowAlignment);
+  uptr end = RoundUpTo(p + size, kShadowAlignment);
+  return TagMemoryAligned(start, end - start, tag);
+}
+
+}  // namespace __hwasan
diff --git a/libsanitizer/hwasan/hwasan_poisoning.h b/libsanitizer/hwasan/hwasan_poisoning.h
new file mode 100644
index 00000000000..61751f7d252
--- /dev/null
+++ b/libsanitizer/hwasan/hwasan_poisoning.h
@@ -0,0 +1,24 @@
+//===-- hwasan_poisoning.h --------------------------------------*- C++ -*-===//
+//
+// 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 a part of HWAddressSanitizer.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef HWASAN_POISONING_H
+#define HWASAN_POISONING_H
+
+#include "hwasan.h"
+
+namespace __hwasan {
+uptr TagMemory(uptr p, uptr size, tag_t tag);
+uptr TagMemoryAligned(uptr p, uptr size, tag_t tag);
+
+}  // namespace __hwasan
+
+#endif  // HWASAN_POISONING_H
diff --git a/libsanitizer/hwasan/hwasan_report.cpp b/libsanitizer/hwasan/hwasan_report.cpp
new file mode 100644
index 00000000000..0be7deeaee1
--- /dev/null
+++ b/libsanitizer/hwasan/hwasan_report.cpp
@@ -0,0 +1,651 @@
+//===-- hwasan_report.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 a part of HWAddressSanitizer.
+//
+// Error reporting.
+//===----------------------------------------------------------------------===//
+
+#include "hwasan_report.h"
+
+#include <dlfcn.h>
+
+#include "hwasan.h"
+#include "hwasan_allocator.h"
+#include "hwasan_globals.h"
+#include "hwasan_mapping.h"
+#include "hwasan_thread.h"
+#include "hwasan_thread_list.h"
+#include "sanitizer_common/sanitizer_allocator_internal.h"
+#include "sanitizer_common/sanitizer_common.h"
+#include "sanitizer_common/sanitizer_flags.h"
+#include "sanitizer_common/sanitizer_mutex.h"
+#include "sanitizer_common/sanitizer_report_decorator.h"
+#include "sanitizer_common/sanitizer_stackdepot.h"
+#include "sanitizer_common/sanitizer_stacktrace_printer.h"
+#include "sanitizer_common/sanitizer_symbolizer.h"
+
+using namespace __sanitizer;
+
+namespace __hwasan {
+
+class ScopedReport {
+ public:
+  ScopedReport(bool fatal = false) : error_message_(1), fatal(fatal) {
+    BlockingMutexLock lock(&error_message_lock_);
+    error_message_ptr_ = fatal ? &error_message_ : nullptr;
+    ++hwasan_report_count;
+  }
+
+  ~ScopedReport() {
+    {
+      BlockingMutexLock lock(&error_message_lock_);
+      if (fatal)
+        SetAbortMessage(error_message_.data());
+      error_message_ptr_ = nullptr;
+    }
+    if (common_flags()->print_module_map >= 2 ||
+        (fatal && common_flags()->print_module_map))
+      DumpProcessMap();
+    if (fatal)
+      Die();
+  }
+
+  static void MaybeAppendToErrorMessage(const char *msg) {
+    BlockingMutexLock lock(&error_message_lock_);
+    if (!error_message_ptr_)
+      return;
+    uptr len = internal_strlen(msg);
+    uptr old_size = error_message_ptr_->size();
+    error_message_ptr_->resize(old_size + len);
+    // overwrite old trailing '\0', keep new trailing '\0' untouched.
+    internal_memcpy(&(*error_message_ptr_)[old_size - 1], msg, len);
+  }
+ private:
+  ScopedErrorReportLock error_report_lock_;
+  InternalMmapVector<char> error_message_;
+  bool fatal;
+
+  static InternalMmapVector<char> *error_message_ptr_;
+  static BlockingMutex error_message_lock_;
+};
+
+InternalMmapVector<char> *ScopedReport::error_message_ptr_;
+BlockingMutex ScopedReport::error_message_lock_;
+
+// If there is an active ScopedReport, append to its error message.
+void AppendToErrorMessageBuffer(const char *buffer) {
+  ScopedReport::MaybeAppendToErrorMessage(buffer);
+}
+
+static StackTrace GetStackTraceFromId(u32 id) {
+  CHECK(id);
+  StackTrace res = StackDepotGet(id);
+  CHECK(res.trace);
+  return res;
+}
+
+// A RAII object that holds a copy of the current thread stack ring buffer.
+// The actual stack buffer may change while we are iterating over it (for
+// example, Printf may call syslog() which can itself be built with hwasan).
+class SavedStackAllocations {
+ public:
+  SavedStackAllocations(StackAllocationsRingBuffer *rb) {
+    uptr size = rb->size() * sizeof(uptr);
+    void *storage =
+        MmapAlignedOrDieOnFatalError(size, size * 2, "saved stack allocations");
+    new (&rb_) StackAllocationsRingBuffer(*rb, storage);
+  }
+
+  ~SavedStackAllocations() {
+    StackAllocationsRingBuffer *rb = get();
+    UnmapOrDie(rb->StartOfStorage(), rb->size() * sizeof(uptr));
+  }
+
+  StackAllocationsRingBuffer *get() {
+    return (StackAllocationsRingBuffer *)&rb_;
+  }
+
+ private:
+  uptr rb_;
+};
+
+class Decorator: public __sanitizer::SanitizerCommonDecorator {
+ public:
+  Decorator() : SanitizerCommonDecorator() { }
+  const char *Access() { return Blue(); }
+  const char *Allocation() const { return Magenta(); }
+  const char *Origin() const { return Magenta(); }
+  const char *Name() const { return Green(); }
+  const char *Location() { return Green(); }
+  const char *Thread() { return Green(); }
+};
+
+static bool FindHeapAllocation(HeapAllocationsRingBuffer *rb, uptr tagged_addr,
+                               HeapAllocationRecord *har, uptr *ring_index,
+                               uptr *num_matching_addrs,
+                               uptr *num_matching_addrs_4b) {
+  if (!rb) return false;
+
+  *num_matching_addrs = 0;
+  *num_matching_addrs_4b = 0;
+  for (uptr i = 0, size = rb->size(); i < size; i++) {
+    auto h = (*rb)[i];
+    if (h.tagged_addr <= tagged_addr &&
+        h.tagged_addr + h.requested_size > tagged_addr) {
+      *har = h;
+      *ring_index = i;
+      return true;
+    }
+
+    // Measure the number of heap ring buffer entries that would have matched
+    // if we had only one entry per address (e.g. if the ring buffer data was
+    // stored at the address itself). This will help us tune the allocator
+    // implementation for MTE.
+    if (UntagAddr(h.tagged_addr) <= UntagAddr(tagged_addr) &&
+        UntagAddr(h.tagged_addr) + h.requested_size > UntagAddr(tagged_addr)) {
+      ++*num_matching_addrs;
+    }
+
+    // Measure the number of heap ring buffer entries that would have matched
+    // if we only had 4 tag bits, which is the case for MTE.
+    auto untag_4b = [](uptr p) {
+      return p & ((1ULL << 60) - 1);
+    };
+    if (untag_4b(h.tagged_addr) <= untag_4b(tagged_addr) &&
+        untag_4b(h.tagged_addr) + h.requested_size > untag_4b(tagged_addr)) {
+      ++*num_matching_addrs_4b;
+    }
+  }
+  return false;
+}
+
+static void PrintStackAllocations(StackAllocationsRingBuffer *sa,
+                                  tag_t addr_tag, uptr untagged_addr) {
+  uptr frames = Min((uptr)flags()->stack_history_size, sa->size());
+  bool found_local = false;
+  for (uptr i = 0; i < frames; i++) {
+    const uptr *record_addr = &(*sa)[i];
+    uptr record = *record_addr;
+    if (!record)
+      break;
+    tag_t base_tag =
+        reinterpret_cast<uptr>(record_addr) >> kRecordAddrBaseTagShift;
+    uptr fp = (record >> kRecordFPShift) << kRecordFPLShift;
+    uptr pc_mask = (1ULL << kRecordFPShift) - 1;
+    uptr pc = record & pc_mask;
+    FrameInfo frame;
+    if (Symbolizer::GetOrInit()->SymbolizeFrame(pc, &frame)) {
+      for (LocalInfo &local : frame.locals) {
+        if (!local.has_frame_offset || !local.has_size || !local.has_tag_offset)
+          continue;
+        tag_t obj_tag = base_tag ^ local.tag_offset;
+        if (obj_tag != addr_tag)
+          continue;
+        // Calculate the offset from the object address to the faulting
+        // address. Because we only store bits 4-19 of FP (bits 0-3 are
+        // guaranteed to be zero), the calculation is performed mod 2^20 and may
+        // harmlessly underflow if the address mod 2^20 is below the object
+        // address.
+        uptr obj_offset =
+            (untagged_addr - fp - local.frame_offset) & (kRecordFPModulus - 1);
+        if (obj_offset >= local.size)
+          continue;
+        if (!found_local) {
+          Printf("Potentially referenced stack objects:\n");
+          found_local = true;
+        }
+        Printf("  %s in %s %s:%d\n", local.name, local.function_name,
+               local.decl_file, local.decl_line);
+      }
+      frame.Clear();
+    }
+  }
+
+  if (found_local)
+    return;
+
+  // We didn't find any locals. Most likely we don't have symbols, so dump
+  // the information that we have for offline analysis.
+  InternalScopedString frame_desc(GetPageSizeCached() * 2);
+  Printf("Previously allocated frames:\n");
+  for (uptr i = 0; i < frames; i++) {
+    const uptr *record_addr = &(*sa)[i];
+    uptr record = *record_addr;
+    if (!record)
+      break;
+    uptr pc_mask = (1ULL << 48) - 1;
+    uptr pc = record & pc_mask;
+    frame_desc.append("  record_addr:0x%zx record:0x%zx",
+                      reinterpret_cast<uptr>(record_addr), record);
+    if (SymbolizedStack *frame = Symbolizer::GetOrInit()->SymbolizePC(pc)) {
+      RenderFrame(&frame_desc, " %F %L\n", 0, frame->info.address, &frame->info,
+                  common_flags()->symbolize_vs_style,
+                  common_flags()->strip_path_prefix);
+      frame->ClearAll();
+    }
+    Printf("%s", frame_desc.data());
+    frame_desc.clear();
+  }
+}
+
+// Returns true if tag == *tag_ptr, reading tags from short granules if
+// necessary. This may return a false positive if tags 1-15 are used as a
+// regular tag rather than a short granule marker.
+static bool TagsEqual(tag_t tag, tag_t *tag_ptr) {
+  if (tag == *tag_ptr)
+    return true;
+  if (*tag_ptr == 0 || *tag_ptr > kShadowAlignment - 1)
+    return false;
+  uptr mem = ShadowToMem(reinterpret_cast<uptr>(tag_ptr));
+  tag_t inline_tag = *reinterpret_cast<tag_t *>(mem + kShadowAlignment - 1);
+  return tag == inline_tag;
+}
+
+// HWASan globals store the size of the global in the descriptor. In cases where
+// we don't have a binary with symbols, we can't grab the size of the global
+// from the debug info - but we might be able to retrieve it from the
+// descriptor. Returns zero if the lookup failed.
+static uptr GetGlobalSizeFromDescriptor(uptr ptr) {
+  // Find the ELF object that this global resides in.
+  Dl_info info;
+  dladdr(reinterpret_cast<void *>(ptr), &info);
+  auto *ehdr = reinterpret_cast<const ElfW(Ehdr) *>(info.dli_fbase);
+  auto *phdr_begin = reinterpret_cast<const ElfW(Phdr) *>(
+      reinterpret_cast<const u8 *>(ehdr) + ehdr->e_phoff);
+
+  // Get the load bias. This is normally the same as the dli_fbase address on
+  // position-independent code, but can be different on non-PIE executables,
+  // binaries using LLD's partitioning feature, or binaries compiled with a
+  // linker script.
+  ElfW(Addr) load_bias = 0;
+  for (const auto &phdr :
+       ArrayRef<const ElfW(Phdr)>(phdr_begin, phdr_begin + ehdr->e_phnum)) {
+    if (phdr.p_type != PT_LOAD || phdr.p_offset != 0)
+      continue;
+    load_bias = reinterpret_cast<ElfW(Addr)>(ehdr) - phdr.p_vaddr;
+    break;
+  }
+
+  // Walk all globals in this ELF object, looking for the one we're interested
+  // in. Once we find it, we can stop iterating and return the size of the
+  // global we're interested in.
+  for (const hwasan_global &global :
+       HwasanGlobalsFor(load_bias, phdr_begin, ehdr->e_phnum))
+    if (global.addr() <= ptr && ptr < global.addr() + global.size())
+      return global.size();
+
+  return 0;
+}
+
+void PrintAddressDescription(
+    uptr tagged_addr, uptr access_size,
+    StackAllocationsRingBuffer *current_stack_allocations) {
+  Decorator d;
+  int num_descriptions_printed = 0;
+  uptr untagged_addr = UntagAddr(tagged_addr);
+
+  // Print some very basic information about the address, if it's a heap.
+  HwasanChunkView chunk = FindHeapChunkByAddress(untagged_addr);
+  if (uptr beg = chunk.Beg()) {
+    uptr size = chunk.ActualSize();
+    Printf("%s[%p,%p) is a %s %s heap chunk; "
+           "size: %zd offset: %zd\n%s",
+           d.Location(),
+           beg, beg + size,
+           chunk.FromSmallHeap() ? "small" : "large",
+           chunk.IsAllocated() ? "allocated" : "unallocated",
+           size, untagged_addr - beg,
+           d.Default());
+  }
+
+  // Check if this looks like a heap buffer overflow by scanning
+  // the shadow left and right and looking for the first adjacent
+  // object with a different memory tag. If that tag matches addr_tag,
+  // check the allocator if it has a live chunk there.
+  tag_t addr_tag = GetTagFromPointer(tagged_addr);
+  tag_t *tag_ptr = reinterpret_cast<tag_t*>(MemToShadow(untagged_addr));
+  tag_t *candidate = nullptr, *left = tag_ptr, *right = tag_ptr;
+  for (int i = 0; i < 1000; i++) {
+    if (TagsEqual(addr_tag, left)) {
+      candidate = left;
+      break;
+    }
+    --left;
+    if (TagsEqual(addr_tag, right)) {
+      candidate = right;
+      break;
+    }
+    ++right;
+  }
+
+  if (candidate) {
+    uptr mem = ShadowToMem(reinterpret_cast<uptr>(candidate));
+    HwasanChunkView chunk = FindHeapChunkByAddress(mem);
+    if (chunk.IsAllocated()) {
+      Printf("%s", d.Location());
+      Printf("%p is located %zd bytes to the %s of %zd-byte region [%p,%p)\n",
+             untagged_addr,
+             candidate == left ? untagged_addr - chunk.End()
+                               : chunk.Beg() - untagged_addr,
+             candidate == left ? "right" : "left", chunk.UsedSize(),
+             chunk.Beg(), chunk.End());
+      Printf("%s", d.Allocation());
+      Printf("allocated here:\n");
+      Printf("%s", d.Default());
+      GetStackTraceFromId(chunk.GetAllocStackId()).Print();
+      num_descriptions_printed++;
+    } else {
+      // Check whether the address points into a loaded library. If so, this is
+      // most likely a global variable.
+      const char *module_name;
+      uptr module_address;
+      Symbolizer *sym = Symbolizer::GetOrInit();
+      if (sym->GetModuleNameAndOffsetForPC(mem, &module_name,
+                                           &module_address)) {
+        DataInfo info;
+        if (sym->SymbolizeData(mem, &info) && info.start) {
+          Printf(
+              "%p is located %zd bytes to the %s of %zd-byte global variable "
+              "%s [%p,%p) in %s\n",
+              untagged_addr,
+              candidate == left ? untagged_addr - (info.start + info.size)
+                                : info.start - untagged_addr,
+              candidate == left ? "right" : "left", info.size, info.name,
+              info.start, info.start + info.size, module_name);
+        } else {
+          uptr size = GetGlobalSizeFromDescriptor(mem);
+          if (size == 0)
+            // We couldn't find the size of the global from the descriptors.
+            Printf(
+                "%p is located to the %s of a global variable in (%s+0x%x)\n",
+                untagged_addr, candidate == left ? "right" : "left",
+                module_name, module_address);
+          else
+            Printf(
+                "%p is located to the %s of a %zd-byte global variable in "
+                "(%s+0x%x)\n",
+                untagged_addr, candidate == left ? "right" : "left", size,
+                module_name, module_address);
+        }
+        num_descriptions_printed++;
+      }
+    }
+  }
+
+  hwasanThreadList().VisitAllLiveThreads([&](Thread *t) {
+    // Scan all threads' ring buffers to find if it's a heap-use-after-free.
+    HeapAllocationRecord har;
+    uptr ring_index, num_matching_addrs, num_matching_addrs_4b;
+    if (FindHeapAllocation(t->heap_allocations(), tagged_addr, &har,
+                           &ring_index, &num_matching_addrs,
+                           &num_matching_addrs_4b)) {
+      Printf("%s", d.Location());
+      Printf("%p is located %zd bytes inside of %zd-byte region [%p,%p)\n",
+             untagged_addr, untagged_addr - UntagAddr(har.tagged_addr),
+             har.requested_size, UntagAddr(har.tagged_addr),
+             UntagAddr(har.tagged_addr) + har.requested_size);
+      Printf("%s", d.Allocation());
+      Printf("freed by thread T%zd here:\n", t->unique_id());
+      Printf("%s", d.Default());
+      GetStackTraceFromId(har.free_context_id).Print();
+
+      Printf("%s", d.Allocation());
+      Printf("previously allocated here:\n", t);
+      Printf("%s", d.Default());
+      GetStackTraceFromId(har.alloc_context_id).Print();
+
+      // Print a developer note: the index of this heap object
+      // in the thread's deallocation ring buffer.
+      Printf("hwasan_dev_note_heap_rb_distance: %zd %zd\n", ring_index + 1,
+             flags()->heap_history_size);
+      Printf("hwasan_dev_note_num_matching_addrs: %zd\n", num_matching_addrs);
+      Printf("hwasan_dev_note_num_matching_addrs_4b: %zd\n",
+             num_matching_addrs_4b);
+
+      t->Announce();
+      num_descriptions_printed++;
+    }
+
+    // Very basic check for stack memory.
+    if (t->AddrIsInStack(untagged_addr)) {
+      Printf("%s", d.Location());
+      Printf("Address %p is located in stack of thread T%zd\n", untagged_addr,
+             t->unique_id());
+      Printf("%s", d.Default());
+      t->Announce();
+
+      auto *sa = (t == GetCurrentThread() && current_stack_allocations)
+                     ? current_stack_allocations
+                     : t->stack_allocations();
+      PrintStackAllocations(sa, addr_tag, untagged_addr);
+      num_descriptions_printed++;
+    }
+  });
+
+  // Print the remaining threads, as an extra information, 1 line per thread.
+  hwasanThreadList().VisitAllLiveThreads([&](Thread *t) { t->Announce(); });
+
+  if (!num_descriptions_printed)
+    // We exhausted our possibilities. Bail out.
+    Printf("HWAddressSanitizer can not describe address in more detail.\n");
+}
+
+void ReportStats() {}
+
+static void PrintTagInfoAroundAddr(tag_t *tag_ptr, uptr num_rows,
+                                   void (*print_tag)(InternalScopedString &s,
+                                                     tag_t *tag)) {
+  const uptr row_len = 16;  // better be power of two.
+  tag_t *center_row_beg = reinterpret_cast<tag_t *>(
+      RoundDownTo(reinterpret_cast<uptr>(tag_ptr), row_len));
+  tag_t *beg_row = center_row_beg - row_len * (num_rows / 2);
+  tag_t *end_row = center_row_beg + row_len * ((num_rows + 1) / 2);
+  InternalScopedString s(GetPageSizeCached() * 8);
+  for (tag_t *row = beg_row; row < end_row; row += row_len) {
+    s.append("%s", row == center_row_beg ? "=>" : "  ");
+    s.append("%p:", row);
+    for (uptr i = 0; i < row_len; i++) {
+      s.append("%s", row + i == tag_ptr ? "[" : " ");
+      print_tag(s, &row[i]);
+      s.append("%s", row + i == tag_ptr ? "]" : " ");
+    }
+    s.append("\n");
+  }
+  Printf("%s", s.data());
+}
+
+static void PrintTagsAroundAddr(tag_t *tag_ptr) {
+  Printf(
+      "Memory tags around the buggy address (one tag corresponds to %zd "
+      "bytes):\n", kShadowAlignment);
+  PrintTagInfoAroundAddr(tag_ptr, 17, [](InternalScopedString &s, tag_t *tag) {
+    s.append("%02x", *tag);
+  });
+
+  Printf(
+      "Tags for short granules around the buggy address (one tag corresponds "
+      "to %zd bytes):\n",
+      kShadowAlignment);
+  PrintTagInfoAroundAddr(tag_ptr, 3, [](InternalScopedString &s, tag_t *tag) {
+    if (*tag >= 1 && *tag <= kShadowAlignment) {
+      uptr granule_addr = ShadowToMem(reinterpret_cast<uptr>(tag));
+      s.append("%02x",
+               *reinterpret_cast<u8 *>(granule_addr + kShadowAlignment - 1));
+    } else {
+      s.append("..");
+    }
+  });
+  Printf(
+      "See "
+      "https://clang.llvm.org/docs/"
+      "HardwareAssistedAddressSanitizerDesign.html#short-granules for a "
+      "description of short granule tags\n");
+}
+
+void ReportInvalidFree(StackTrace *stack, uptr tagged_addr) {
+  ScopedReport R(flags()->halt_on_error);
+
+  uptr untagged_addr = UntagAddr(tagged_addr);
+  tag_t ptr_tag = GetTagFromPointer(tagged_addr);
+  tag_t *tag_ptr = reinterpret_cast<tag_t*>(MemToShadow(untagged_addr));
+  tag_t mem_tag = *tag_ptr;
+  Decorator d;
+  Printf("%s", d.Error());
+  uptr pc = stack->size ? stack->trace[0] : 0;
+  const char *bug_type = "invalid-free";
+  Report("ERROR: %s: %s on address %p at pc %p\n", SanitizerToolName, bug_type,
+         untagged_addr, pc);
+  Printf("%s", d.Access());
+  Printf("tags: %02x/%02x (ptr/mem)\n", ptr_tag, mem_tag);
+  Printf("%s", d.Default());
+
+  stack->Print();
+
+  PrintAddressDescription(tagged_addr, 0, nullptr);
+
+  PrintTagsAroundAddr(tag_ptr);
+
+  ReportErrorSummary(bug_type, stack);
+}
+
+void ReportTailOverwritten(StackTrace *stack, uptr tagged_addr, uptr orig_size,
+                           const u8 *expected) {
+  uptr tail_size = kShadowAlignment - (orig_size % kShadowAlignment);
+  ScopedReport R(flags()->halt_on_error);
+  Decorator d;
+  uptr untagged_addr = UntagAddr(tagged_addr);
+  Printf("%s", d.Error());
+  const char *bug_type = "allocation-tail-overwritten";
+  Report("ERROR: %s: %s; heap object [%p,%p) of size %zd\n", SanitizerToolName,
+         bug_type, untagged_addr, untagged_addr + orig_size, orig_size);
+  Printf("\n%s", d.Default());
+  stack->Print();
+  HwasanChunkView chunk = FindHeapChunkByAddress(untagged_addr);
+  if (chunk.Beg()) {
+    Printf("%s", d.Allocation());
+    Printf("allocated here:\n");
+    Printf("%s", d.Default());
+    GetStackTraceFromId(chunk.GetAllocStackId()).Print();
+  }
+
+  InternalScopedString s(GetPageSizeCached() * 8);
+  CHECK_GT(tail_size, 0U);
+  CHECK_LT(tail_size, kShadowAlignment);
+  u8 *tail = reinterpret_cast<u8*>(untagged_addr + orig_size);
+  s.append("Tail contains: ");
+  for (uptr i = 0; i < kShadowAlignment - tail_size; i++)
+    s.append(".. ");
+  for (uptr i = 0; i < tail_size; i++)
+    s.append("%02x ", tail[i]);
+  s.append("\n");
+  s.append("Expected:      ");
+  for (uptr i = 0; i < kShadowAlignment - tail_size; i++)
+    s.append(".. ");
+  for (uptr i = 0; i < tail_size; i++)
+    s.append("%02x ", expected[i]);
+  s.append("\n");
+  s.append("               ");
+  for (uptr i = 0; i < kShadowAlignment - tail_size; i++)
+    s.append("   ");
+  for (uptr i = 0; i < tail_size; i++)
+    s.append("%s ", expected[i] != tail[i] ? "^^" : "  ");
+
+  s.append("\nThis error occurs when a buffer overflow overwrites memory\n"
+    "to the right of a heap object, but within the %zd-byte granule, e.g.\n"
+    "   char *x = new char[20];\n"
+    "   x[25] = 42;\n"
+    "%s does not detect such bugs in uninstrumented code at the time of write,"
+    "\nbut can detect them at the time of free/delete.\n"
+    "To disable this feature set HWASAN_OPTIONS=free_checks_tail_magic=0\n",
+    kShadowAlignment, SanitizerToolName);
+  Printf("%s", s.data());
+  GetCurrentThread()->Announce();
+
+  tag_t *tag_ptr = reinterpret_cast<tag_t*>(MemToShadow(untagged_addr));
+  PrintTagsAroundAddr(tag_ptr);
+
+  ReportErrorSummary(bug_type, stack);
+}
+
+void ReportTagMismatch(StackTrace *stack, uptr tagged_addr, uptr access_size,
+                       bool is_store, bool fatal, uptr *registers_frame) {
+  ScopedReport R(fatal);
+  SavedStackAllocations current_stack_allocations(
+      GetCurrentThread()->stack_allocations());
+
+  Decorator d;
+  Printf("%s", d.Error());
+  uptr untagged_addr = UntagAddr(tagged_addr);
+  // TODO: when possible, try to print heap-use-after-free, etc.
+  const char *bug_type = "tag-mismatch";
+  uptr pc = stack->size ? stack->trace[0] : 0;
+  Report("ERROR: %s: %s on address %p at pc %p\n", SanitizerToolName, bug_type,
+         untagged_addr, pc);
+
+  Thread *t = GetCurrentThread();
+
+  sptr offset =
+      __hwasan_test_shadow(reinterpret_cast<void *>(tagged_addr), access_size);
+  CHECK(offset >= 0 && offset < static_cast<sptr>(access_size));
+  tag_t ptr_tag = GetTagFromPointer(tagged_addr);
+  tag_t *tag_ptr =
+      reinterpret_cast<tag_t *>(MemToShadow(untagged_addr + offset));
+  tag_t mem_tag = *tag_ptr;
+
+  Printf("%s", d.Access());
+  Printf("%s of size %zu at %p tags: %02x/%02x (ptr/mem) in thread T%zd\n",
+         is_store ? "WRITE" : "READ", access_size, untagged_addr, ptr_tag,
+         mem_tag, t->unique_id());
+  if (offset != 0)
+    Printf("Invalid access starting at offset [%zu, %zu)\n", offset,
+           Min(access_size, static_cast<uptr>(offset) + (1 << kShadowScale)));
+  Printf("%s", d.Default());
+
+  stack->Print();
+
+  PrintAddressDescription(tagged_addr, access_size,
+                          current_stack_allocations.get());
+  t->Announce();
+
+  PrintTagsAroundAddr(tag_ptr);
+
+  if (registers_frame)
+    ReportRegisters(registers_frame, pc);
+
+  ReportErrorSummary(bug_type, stack);
+}
+
+// See the frame breakdown defined in __hwasan_tag_mismatch (from
+// hwasan_tag_mismatch_aarch64.S).
+void ReportRegisters(uptr *frame, uptr pc) {
+  Printf("Registers where the failure occurred (pc %p):\n", pc);
+
+  // We explicitly print a single line (4 registers/line) each iteration to
+  // reduce the amount of logcat error messages printed. Each Printf() will
+  // result in a new logcat line, irrespective of whether a newline is present,
+  // and so we wish to reduce the number of Printf() calls we have to make.
+  Printf("    x0  %016llx  x1  %016llx  x2  %016llx  x3  %016llx\n",
+       frame[0], frame[1], frame[2], frame[3]);
+  Printf("    x4  %016llx  x5  %016llx  x6  %016llx  x7  %016llx\n",
+       frame[4], frame[5], frame[6], frame[7]);
+  Printf("    x8  %016llx  x9  %016llx  x10 %016llx  x11 %016llx\n",
+       frame[8], frame[9], frame[10], frame[11]);
+  Printf("    x12 %016llx  x13 %016llx  x14 %016llx  x15 %016llx\n",
+       frame[12], frame[13], frame[14], frame[15]);
+  Printf("    x16 %016llx  x17 %016llx  x18 %016llx  x19 %016llx\n",
+       frame[16], frame[17], frame[18], frame[19]);
+  Printf("    x20 %016llx  x21 %016llx  x22 %016llx  x23 %016llx\n",
+       frame[20], frame[21], frame[22], frame[23]);
+  Printf("    x24 %016llx  x25 %016llx  x26 %016llx  x27 %016llx\n",
+       frame[24], frame[25], frame[26], frame[27]);
+  Printf("    x28 %016llx  x29 %016llx  x30 %016llx\n",
+       frame[28], frame[29], frame[30]);
+}
+
+}  // namespace __hwasan
diff --git a/libsanitizer/hwasan/hwasan_report.h b/libsanitizer/hwasan/hwasan_report.h
new file mode 100644
index 00000000000..de86c38fc01
--- /dev/null
+++ b/libsanitizer/hwasan/hwasan_report.h
@@ -0,0 +1,35 @@
+//===-- hwasan_report.h -----------------------------------------*- C++ -*-===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This file is a part of HWAddressSanitizer. HWASan-private header for error
+/// reporting functions.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef HWASAN_REPORT_H
+#define HWASAN_REPORT_H
+
+#include "sanitizer_common/sanitizer_internal_defs.h"
+#include "sanitizer_common/sanitizer_stacktrace.h"
+
+namespace __hwasan {
+
+void ReportStats();
+void ReportTagMismatch(StackTrace *stack, uptr addr, uptr access_size,
+                       bool is_store, bool fatal, uptr *registers_frame);
+void ReportInvalidFree(StackTrace *stack, uptr addr);
+void ReportTailOverwritten(StackTrace *stack, uptr addr, uptr orig_size,
+                           const u8 *expected);
+void ReportRegisters(uptr *registers_frame, uptr pc);
+void ReportAtExitStatistics();
+
+
+}  // namespace __hwasan
+
+#endif  // HWASAN_REPORT_H
diff --git a/libsanitizer/hwasan/hwasan_setjmp.S b/libsanitizer/hwasan/hwasan_setjmp.S
new file mode 100644
index 00000000000..0c135433194
--- /dev/null
+++ b/libsanitizer/hwasan/hwasan_setjmp.S
@@ -0,0 +1,100 @@
+//===-- hwasan_setjmp.S --------------------------------------------------------===//
+//
+// 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 a part of HWAddressSanitizer.
+//
+// HWAddressSanitizer runtime.
+//===----------------------------------------------------------------------===//
+
+#include "sanitizer_common/sanitizer_asm.h"
+
+#if HWASAN_WITH_INTERCEPTORS && defined(__aarch64__)
+#include "sanitizer_common/sanitizer_platform.h"
+
+// We want to save the context of the calling function.
+// That requires
+// 1) No modification of the link register by this function.
+// 2) No modification of the stack pointer by this function.
+// 3) (no modification of any other saved register, but that's not really going
+// to occur, and hence isn't as much of a worry).
+//
+// There's essentially no way to ensure that the compiler will not modify the
+// stack pointer when compiling a C function.
+// Hence we have to write this function in assembly.
+
+.section .text
+.file "hwasan_setjmp.S"
+
+.global __interceptor_setjmp
+ASM_TYPE_FUNCTION(__interceptor_setjmp)
+__interceptor_setjmp:
+  CFI_STARTPROC
+  mov	x1, #0
+  b	__interceptor_sigsetjmp
+  CFI_ENDPROC
+ASM_SIZE(__interceptor_setjmp)
+
+#if SANITIZER_ANDROID
+// Bionic also defines a function `setjmp` that calls `sigsetjmp` saving the
+// current signal.
+.global __interceptor_setjmp_bionic
+ASM_TYPE_FUNCTION(__interceptor_setjmp_bionic)
+__interceptor_setjmp_bionic:
+  CFI_STARTPROC
+  mov	x1, #1
+  b	__interceptor_sigsetjmp
+  CFI_ENDPROC
+ASM_SIZE(__interceptor_setjmp_bionic)
+#endif
+
+.global __interceptor_sigsetjmp
+ASM_TYPE_FUNCTION(__interceptor_sigsetjmp)
+__interceptor_sigsetjmp:
+  CFI_STARTPROC
+  stp	x19, x20, [x0, #0<<3]
+  stp	x21, x22, [x0, #2<<3]
+  stp	x23, x24, [x0, #4<<3]
+  stp	x25, x26, [x0, #6<<3]
+  stp	x27, x28, [x0, #8<<3]
+  stp	x29, x30, [x0, #10<<3]
+  stp	 d8,  d9, [x0, #14<<3]
+  stp	d10, d11, [x0, #16<<3]
+  stp	d12, d13, [x0, #18<<3]
+  stp	d14, d15, [x0, #20<<3]
+  mov	x2,  sp
+  str	x2,  [x0, #13<<3]
+  // We always have the second argument to __sigjmp_save (savemask) set, since
+  // the _setjmp function above has set it for us as `false`.
+  // This function is defined in hwasan_interceptors.cc
+  b	__sigjmp_save
+  CFI_ENDPROC
+ASM_SIZE(__interceptor_sigsetjmp)
+
+
+.macro ALIAS first second
+  .globl \second
+  .equ \second\(), \first
+.endm
+
+#if SANITIZER_ANDROID
+ALIAS __interceptor_sigsetjmp, sigsetjmp
+.weak sigsetjmp
+
+ALIAS __interceptor_setjmp_bionic, setjmp
+.weak setjmp
+#else
+ALIAS __interceptor_sigsetjmp, __sigsetjmp
+.weak __sigsetjmp
+#endif
+
+ALIAS __interceptor_setjmp, _setjmp
+.weak _setjmp
+#endif
+
+// We do not need executable stack.
+NO_EXEC_STACK_DIRECTIVE
diff --git a/libsanitizer/hwasan/hwasan_tag_mismatch_aarch64.S b/libsanitizer/hwasan/hwasan_tag_mismatch_aarch64.S
new file mode 100644
index 00000000000..08df12736bb
--- /dev/null
+++ b/libsanitizer/hwasan/hwasan_tag_mismatch_aarch64.S
@@ -0,0 +1,152 @@
+#include "sanitizer_common/sanitizer_asm.h"
+
+// The content of this file is AArch64-only:
+#if defined(__aarch64__)
+
+// The responsibility of the HWASan entry point in compiler-rt is to primarily
+// readjust the stack from the callee and save the current register values to
+// the stack.
+// This entry point function should be called from a __hwasan_check_* symbol.
+// These are generated during a lowering pass in the backend, and are found in
+// AArch64AsmPrinter::EmitHwasanMemaccessSymbols(). Please look there for
+// further information.
+// The __hwasan_check_* caller of this function should have expanded the stack
+// and saved the previous values of x0, x1, x29, and x30. This function will
+// "consume" these saved values and treats it as part of its own stack frame.
+// In this sense, the __hwasan_check_* callee and this function "share" a stack
+// frame. This allows us to omit having unwinding information (.cfi_*) present
+// in every __hwasan_check_* function, therefore reducing binary size. This is
+// particularly important as hwasan_check_* instances are duplicated in every
+// translation unit where HWASan is enabled.
+// This function calls HwasanTagMismatch to step back into the C++ code that
+// completes the stack unwinding and error printing. This function is is not
+// permitted to return.
+
+
+// Frame from __hwasan_check_:
+// |              ...                |
+// |              ...                |
+// | Previous stack frames...        |
+// +=================================+
+// | Unused 8-bytes for maintaining  |
+// | 16-byte SP alignment.           |
+// +---------------------------------+
+// | Return address (x30) for caller |
+// | of __hwasan_check_*.            |
+// +---------------------------------+
+// | Frame address (x29) for caller  |
+// | of __hwasan_check_*             |
+// +---------------------------------+ <-- [SP + 232]
+// |              ...                |
+// |                                 |
+// | Stack frame space for x2 - x28. |
+// |                                 |
+// |              ...                |
+// +---------------------------------+ <-- [SP + 16]
+// |                                 |
+// | Saved x1, as __hwasan_check_*   |
+// | clobbers it.                    |
+// +---------------------------------+
+// | Saved x0, likewise above.       |
+// +---------------------------------+ <-- [x30 / SP]
+
+// This function takes two arguments:
+//   * x0: The data address.
+//   * x1: The encoded access info for the failing access.
+
+// This function has two entry points. The first, __hwasan_tag_mismatch, is used
+// by clients that were compiled without short tag checks (i.e. binaries built
+// by older compilers and binaries targeting older runtimes). In this case the
+// outlined tag check will be missing the code handling short tags (which won't
+// be used in the binary's own stack variables but may be used on the heap
+// or stack variables in other binaries), so the check needs to be done here.
+//
+// The second, __hwasan_tag_mismatch_v2, is used by binaries targeting newer
+// runtimes. This entry point bypasses the short tag check since it will have
+// already been done as part of the outlined tag check. Since tag mismatches are
+// uncommon, there isn't a significant performance benefit to being able to
+// bypass the check; the main benefits are that we can sometimes avoid
+// clobbering the x17 register in error reports, and that the program will have
+// a runtime dependency on the __hwasan_tag_mismatch_v2 symbol therefore it will
+// fail to start up given an older (i.e. incompatible) runtime.
+.section .text
+.file "hwasan_tag_mismatch_aarch64.S"
+.global __hwasan_tag_mismatch
+.type __hwasan_tag_mismatch, %function
+__hwasan_tag_mismatch:
+  // Compute the granule position one past the end of the access.
+  mov x16, #1
+  and x17, x1, #0xf
+  lsl x16, x16, x17
+  and x17, x0, #0xf
+  add x17, x16, x17
+
+  // Load the shadow byte again and check whether it is a short tag within the
+  // range of the granule position computed above.
+  ubfx x16, x0, #4, #52
+  ldrb w16, [x9, x16]
+  cmp w16, #0xf
+  b.hi __hwasan_tag_mismatch_v2
+  cmp w16, w17
+  b.lo __hwasan_tag_mismatch_v2
+
+  // Load the real tag from the last byte of the granule and compare against
+  // the pointer tag.
+  orr x16, x0, #0xf
+  ldrb w16, [x16]
+  cmp x16, x0, lsr #56
+  b.ne __hwasan_tag_mismatch_v2
+
+  // Restore x0, x1 and sp to their values from before the __hwasan_tag_mismatch
+  // call and resume execution.
+  ldp x0, x1, [sp], #256
+  ret
+
+.global __hwasan_tag_mismatch_v2
+.type __hwasan_tag_mismatch_v2, %function
+__hwasan_tag_mismatch_v2:
+  CFI_STARTPROC
+
+  // Set the CFA to be the return address for caller of __hwasan_check_*. Note
+  // that we do not emit CFI predicates to describe the contents of this stack
+  // frame, as this proxy entry point should never be debugged. The contents
+  // are static and are handled by the unwinder after calling
+  // __hwasan_tag_mismatch. The frame pointer is already correctly setup
+  // by __hwasan_check_*.
+  add x29, sp, #232
+  CFI_DEF_CFA(w29, 24)
+  CFI_OFFSET(w30, -16)
+  CFI_OFFSET(w29, -24)
+
+  // Save the rest of the registers into the preallocated space left by
+  // __hwasan_check.
+  str     x28,      [sp, #224]
+  stp     x26, x27, [sp, #208]
+  stp     x24, x25, [sp, #192]
+  stp     x22, x23, [sp, #176]
+  stp     x20, x21, [sp, #160]
+  stp     x18, x19, [sp, #144]
+  stp     x16, x17, [sp, #128]
+  stp     x14, x15, [sp, #112]
+  stp     x12, x13, [sp, #96]
+  stp     x10, x11, [sp, #80]
+  stp     x8,  x9,  [sp, #64]
+  stp     x6,  x7,  [sp, #48]
+  stp     x4,  x5,  [sp, #32]
+  stp     x2,  x3,  [sp, #16]
+
+  // Pass the address of the frame to __hwasan_tag_mismatch4, so that it can
+  // extract the saved registers from this frame without having to worry about
+  // finding this frame.
+  mov x2, sp
+
+  bl __hwasan_tag_mismatch4
+  CFI_ENDPROC
+
+.Lfunc_end0:
+  .size __hwasan_tag_mismatch, .Lfunc_end0-__hwasan_tag_mismatch
+
+#endif  // defined(__aarch64__)
+
+// We do not need executable stack.
+NO_EXEC_STACK_DIRECTIVE
diff --git a/libsanitizer/hwasan/hwasan_thread.cpp b/libsanitizer/hwasan/hwasan_thread.cpp
new file mode 100644
index 00000000000..b81a6350c05
--- /dev/null
+++ b/libsanitizer/hwasan/hwasan_thread.cpp
@@ -0,0 +1,133 @@
+
+#include "hwasan.h"
+#include "hwasan_mapping.h"
+#include "hwasan_thread.h"
+#include "hwasan_poisoning.h"
+#include "hwasan_interface_internal.h"
+
+#include "sanitizer_common/sanitizer_file.h"
+#include "sanitizer_common/sanitizer_placement_new.h"
+#include "sanitizer_common/sanitizer_tls_get_addr.h"
+
+
+namespace __hwasan {
+
+static u32 RandomSeed() {
+  u32 seed;
+  do {
+    if (UNLIKELY(!GetRandom(reinterpret_cast<void *>(&seed), sizeof(seed),
+                            /*blocking=*/false))) {
+      seed = static_cast<u32>(
+          (NanoTime() >> 12) ^
+          (reinterpret_cast<uptr>(__builtin_frame_address(0)) >> 4));
+    }
+  } while (!seed);
+  return seed;
+}
+
+void Thread::InitRandomState() {
+  random_state_ = flags()->random_tags ? RandomSeed() : unique_id_;
+
+  // Push a random number of zeros onto the ring buffer so that the first stack
+  // tag base will be random.
+  for (tag_t i = 0, e = GenerateRandomTag(); i != e; ++i)
+    stack_allocations_->push(0);
+}
+
+void Thread::Init(uptr stack_buffer_start, uptr stack_buffer_size) {
+  static u64 unique_id;
+  unique_id_ = unique_id++;
+  if (auto sz = flags()->heap_history_size)
+    heap_allocations_ = HeapAllocationsRingBuffer::New(sz);
+
+  HwasanTSDThreadInit();  // Only needed with interceptors.
+  uptr *ThreadLong = GetCurrentThreadLongPtr();
+  // The following implicitly sets (this) as the current thread.
+  stack_allocations_ = new (ThreadLong)
+      StackAllocationsRingBuffer((void *)stack_buffer_start, stack_buffer_size);
+  // Check that it worked.
+  CHECK_EQ(GetCurrentThread(), this);
+
+  // ScopedTaggingDisable needs GetCurrentThread to be set up.
+  ScopedTaggingDisabler disabler;
+
+  uptr tls_size;
+  uptr stack_size;
+  GetThreadStackAndTls(IsMainThread(), &stack_bottom_, &stack_size, &tls_begin_,
+                       &tls_size);
+  stack_top_ = stack_bottom_ + stack_size;
+  tls_end_ = tls_begin_ + tls_size;
+
+  if (stack_bottom_) {
+    int local;
+    CHECK(AddrIsInStack((uptr)&local));
+    CHECK(MemIsApp(stack_bottom_));
+    CHECK(MemIsApp(stack_top_ - 1));
+  }
+
+  if (flags()->verbose_threads) {
+    if (IsMainThread()) {
+      Printf("sizeof(Thread): %zd sizeof(HeapRB): %zd sizeof(StackRB): %zd\n",
+             sizeof(Thread), heap_allocations_->SizeInBytes(),
+             stack_allocations_->size() * sizeof(uptr));
+    }
+    Print("Creating  : ");
+  }
+}
+
+void Thread::ClearShadowForThreadStackAndTLS() {
+  if (stack_top_ != stack_bottom_)
+    TagMemory(stack_bottom_, stack_top_ - stack_bottom_, 0);
+  if (tls_begin_ != tls_end_)
+    TagMemory(tls_begin_, tls_end_ - tls_begin_, 0);
+}
+
+void Thread::Destroy() {
+  if (flags()->verbose_threads)
+    Print("Destroying: ");
+  AllocatorSwallowThreadLocalCache(allocator_cache());
+  ClearShadowForThreadStackAndTLS();
+  if (heap_allocations_)
+    heap_allocations_->Delete();
+  DTLS_Destroy();
+  // Unregister this as the current thread.
+  // Instrumented code can not run on this thread from this point onwards, but
+  // malloc/free can still be served. Glibc may call free() very late, after all
+  // TSD destructors are done.
+  CHECK_EQ(GetCurrentThread(), this);
+  *GetCurrentThreadLongPtr() = 0;
+}
+
+void Thread::Print(const char *Prefix) {
+  Printf("%sT%zd %p stack: [%p,%p) sz: %zd tls: [%p,%p)\n", Prefix,
+         unique_id_, this, stack_bottom(), stack_top(),
+         stack_top() - stack_bottom(),
+         tls_begin(), tls_end());
+}
+
+static u32 xorshift(u32 state) {
+  state ^= state << 13;
+  state ^= state >> 17;
+  state ^= state << 5;
+  return state;
+}
+
+// Generate a (pseudo-)random non-zero tag.
+tag_t Thread::GenerateRandomTag() {
+  if (tagging_disabled_) return 0;
+  tag_t tag;
+  do {
+    if (flags()->random_tags) {
+      if (!random_buffer_)
+        random_buffer_ = random_state_ = xorshift(random_state_);
+      CHECK(random_buffer_);
+      tag = random_buffer_ & 0xFF;
+      random_buffer_ >>= 8;
+    } else {
+      tag = random_state_ = (random_state_ + 1) & 0xFF;
+    }
+  } while (!tag);
+  return tag;
+}
+
+} // namespace __hwasan
diff --git a/libsanitizer/hwasan/hwasan_thread.h b/libsanitizer/hwasan/hwasan_thread.h
new file mode 100644
index 00000000000..ebcdb791fb3
--- /dev/null
+++ b/libsanitizer/hwasan/hwasan_thread.h
@@ -0,0 +1,98 @@
+//===-- hwasan_thread.h -----------------------------------------*- C++ -*-===//
+//
+// 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 a part of HWAddressSanitizer.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef HWASAN_THREAD_H
+#define HWASAN_THREAD_H
+
+#include "hwasan_allocator.h"
+#include "sanitizer_common/sanitizer_common.h"
+#include "sanitizer_common/sanitizer_ring_buffer.h"
+
+namespace __hwasan {
+
+typedef __sanitizer::CompactRingBuffer<uptr> StackAllocationsRingBuffer;
+
+class Thread {
+ public:
+  void Init(uptr stack_buffer_start, uptr stack_buffer_size);  // Must be called from the thread itself.
+  void InitRandomState();
+  void Destroy();
+
+  uptr stack_top() { return stack_top_; }
+  uptr stack_bottom() { return stack_bottom_; }
+  uptr stack_size() { return stack_top() - stack_bottom(); }
+  uptr tls_begin() { return tls_begin_; }
+  uptr tls_end() { return tls_end_; }
+  bool IsMainThread() { return unique_id_ == 0; }
+
+  bool AddrIsInStack(uptr addr) {
+    return addr >= stack_bottom_ && addr < stack_top_;
+  }
+
+  AllocatorCache *allocator_cache() { return &allocator_cache_; }
+  HeapAllocationsRingBuffer *heap_allocations() { return heap_allocations_; }
+  StackAllocationsRingBuffer *stack_allocations() { return stack_allocations_; }
+
+  tag_t GenerateRandomTag();
+
+  void DisableTagging() { tagging_disabled_++; }
+  void EnableTagging() { tagging_disabled_--; }
+
+  u64 unique_id() const { return unique_id_; }
+  void Announce() {
+    if (announced_) return;
+    announced_ = true;
+    Print("Thread: ");
+  }
+
+  uptr &vfork_spill() { return vfork_spill_; }
+
+ private:
+  // NOTE: There is no Thread constructor. It is allocated
+  // via mmap() and *must* be valid in zero-initialized state.
+  void ClearShadowForThreadStackAndTLS();
+  void Print(const char *prefix);
+  uptr vfork_spill_;
+  uptr stack_top_;
+  uptr stack_bottom_;
+  uptr tls_begin_;
+  uptr tls_end_;
+
+  u32 random_state_;
+  u32 random_buffer_;
+
+  AllocatorCache allocator_cache_;
+  HeapAllocationsRingBuffer *heap_allocations_;
+  StackAllocationsRingBuffer *stack_allocations_;
+
+  Thread *next_;  // All live threads form a linked list.
+
+  u64 unique_id_;  // counting from zero.
+
+  u32 tagging_disabled_;  // if non-zero, malloc uses zero tag in this thread.
+
+  bool announced_;
+
+  friend struct ThreadListHead;
+};
+
+Thread *GetCurrentThread();
+uptr *GetCurrentThreadLongPtr();
+
+struct ScopedTaggingDisabler {
+  ScopedTaggingDisabler() { GetCurrentThread()->DisableTagging(); }
+  ~ScopedTaggingDisabler() { GetCurrentThread()->EnableTagging(); }
+};
+
+} // namespace __hwasan
+
+#endif // HWASAN_THREAD_H
diff --git a/libsanitizer/hwasan/hwasan_thread_list.cpp b/libsanitizer/hwasan/hwasan_thread_list.cpp
new file mode 100644
index 00000000000..a31eee84ed9
--- /dev/null
+++ b/libsanitizer/hwasan/hwasan_thread_list.cpp
@@ -0,0 +1,15 @@
+#include "hwasan_thread_list.h"
+
+namespace __hwasan {
+static ALIGNED(16) char thread_list_placeholder[sizeof(HwasanThreadList)];
+static HwasanThreadList *hwasan_thread_list;
+
+HwasanThreadList &hwasanThreadList() { return *hwasan_thread_list; }
+
+void InitThreadList(uptr storage, uptr size) {
+  CHECK(hwasan_thread_list == nullptr);
+  hwasan_thread_list =
+      new (thread_list_placeholder) HwasanThreadList(storage, size);
+}
+
+} // namespace
diff --git a/libsanitizer/hwasan/hwasan_thread_list.h b/libsanitizer/hwasan/hwasan_thread_list.h
new file mode 100644
index 00000000000..914b632d977
--- /dev/null
+++ b/libsanitizer/hwasan/hwasan_thread_list.h
@@ -0,0 +1,215 @@
+//===-- hwasan_thread_list.h ------------------------------------*- C++ -*-===//
+//
+// 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 a part of HWAddressSanitizer.
+//
+//===----------------------------------------------------------------------===//
+
+// HwasanThreadList is a registry for live threads, as well as an allocator for
+// HwasanThread objects and their stack history ring buffers. There are
+// constraints on memory layout of the shadow region and CompactRingBuffer that
+// are part of the ABI contract between compiler-rt and llvm.
+//
+// * Start of the shadow memory region is aligned to 2**kShadowBaseAlignment.
+// * All stack ring buffers are located within (2**kShadowBaseAlignment)
+// sized region below and adjacent to the shadow region.
+// * Each ring buffer has a size of (2**N)*4096 where N is in [0, 8), and is
+// aligned to twice its size. The value of N can be different for each buffer.
+//
+// These constrains guarantee that, given an address A of any element of the
+// ring buffer,
+//     A_next = (A + sizeof(uptr)) & ~((1 << (N + 13)) - 1)
+//   is the address of the next element of that ring buffer (with wrap-around).
+// And, with K = kShadowBaseAlignment,
+//     S = (A | ((1 << K) - 1)) + 1
+//   (align up to kShadowBaseAlignment) is the start of the shadow region.
+//
+// These calculations are used in compiler instrumentation to update the ring
+// buffer and obtain the base address of shadow using only two inputs: address
+// of the current element of the ring buffer, and N (i.e. size of the ring
+// buffer). Since the value of N is very limited, we pack both inputs into a
+// single thread-local word as
+//   (1 << (N + 56)) | A
+// See the implementation of class CompactRingBuffer, which is what is stored in
+// said thread-local word.
+//
+// Note the unusual way of aligning up the address of the shadow:
+//   (A | ((1 << K) - 1)) + 1
+// It is only correct if A is not already equal to the shadow base address, but
+// it saves 2 instructions on AArch64.
+
+#include "hwasan.h"
+#include "hwasan_allocator.h"
+#include "hwasan_flags.h"
+#include "hwasan_thread.h"
+
+#include "sanitizer_common/sanitizer_placement_new.h"
+
+namespace __hwasan {
+
+static uptr RingBufferSize() {
+  uptr desired_bytes = flags()->stack_history_size * sizeof(uptr);
+  // FIXME: increase the limit to 8 once this bug is fixed:
+  // https://bugs.llvm.org/show_bug.cgi?id=39030
+  for (int shift = 1; shift < 7; ++shift) {
+    uptr size = 4096 * (1ULL << shift);
+    if (size >= desired_bytes)
+      return size;
+  }
+  Printf("stack history size too large: %d\n", flags()->stack_history_size);
+  CHECK(0);
+  return 0;
+}
+
+struct ThreadListHead {
+  Thread *list_;
+
+  ThreadListHead() : list_(nullptr) {}
+
+  void Push(Thread *t) {
+    t->next_ = list_;
+    list_ = t;
+  }
+
+  Thread *Pop() {
+    Thread *t = list_;
+    if (t)
+      list_ = t->next_;
+    return t;
+  }
+
+  void Remove(Thread *t) {
+    Thread **cur = &list_;
+    while (*cur != t) cur = &(*cur)->next_;
+    CHECK(*cur && "thread not found");
+    *cur = (*cur)->next_;
+  }
+
+  template <class CB>
+  void ForEach(CB cb) {
+    Thread *t = list_;
+    while (t) {
+      cb(t);
+      t = t->next_;
+    }
+  }
+};
+
+struct ThreadStats {
+  uptr n_live_threads;
+  uptr total_stack_size;
+};
+
+class HwasanThreadList {
+ public:
+  HwasanThreadList(uptr storage, uptr size)
+      : free_space_(storage), free_space_end_(storage + size) {
+    // [storage, storage + size) is used as a vector of
+    // thread_alloc_size_-sized, ring_buffer_size_*2-aligned elements.
+    // Each element contains
+    // * a ring buffer at offset 0,
+    // * a Thread object at offset ring_buffer_size_.
+    ring_buffer_size_ = RingBufferSize();
+    thread_alloc_size_ =
+        RoundUpTo(ring_buffer_size_ + sizeof(Thread), ring_buffer_size_ * 2);
+  }
+
+  Thread *CreateCurrentThread() {
+    Thread *t;
+    {
+      SpinMutexLock l(&list_mutex_);
+      t = free_list_.Pop();
+      if (t) {
+        uptr start = (uptr)t - ring_buffer_size_;
+        internal_memset((void *)start, 0, ring_buffer_size_ + sizeof(Thread));
+      } else {
+        t = AllocThread();
+      }
+      live_list_.Push(t);
+    }
+    t->Init((uptr)t - ring_buffer_size_, ring_buffer_size_);
+    AddThreadStats(t);
+    return t;
+  }
+
+  void DontNeedThread(Thread *t) {
+    uptr start = (uptr)t - ring_buffer_size_;
+    ReleaseMemoryPagesToOS(start, start + thread_alloc_size_);
+  }
+
+  void ReleaseThread(Thread *t) {
+    RemoveThreadStats(t);
+    t->Destroy();
+    SpinMutexLock l(&list_mutex_);
+    live_list_.Remove(t);
+    free_list_.Push(t);
+    DontNeedThread(t);
+  }
+
+  Thread *GetThreadByBufferAddress(uptr p) {
+    return (Thread *)(RoundDownTo(p, ring_buffer_size_ * 2) +
+                      ring_buffer_size_);
+  }
+
+  uptr MemoryUsedPerThread() {
+    uptr res = sizeof(Thread) + ring_buffer_size_;
+    if (auto sz = flags()->heap_history_size)
+      res += HeapAllocationsRingBuffer::SizeInBytes(sz);
+    return res;
+  }
+
+  template <class CB>
+  void VisitAllLiveThreads(CB cb) {
+    SpinMutexLock l(&list_mutex_);
+    live_list_.ForEach(cb);
+  }
+
+  void AddThreadStats(Thread *t) {
+    SpinMutexLock l(&stats_mutex_);
+    stats_.n_live_threads++;
+    stats_.total_stack_size += t->stack_size();
+  }
+
+  void RemoveThreadStats(Thread *t) {
+    SpinMutexLock l(&stats_mutex_);
+    stats_.n_live_threads--;
+    stats_.total_stack_size -= t->stack_size();
+  }
+
+  ThreadStats GetThreadStats() {
+    SpinMutexLock l(&stats_mutex_);
+    return stats_;
+  }
+
+ private:
+  Thread *AllocThread() {
+    uptr align = ring_buffer_size_ * 2;
+    CHECK(IsAligned(free_space_, align));
+    Thread *t = (Thread *)(free_space_ + ring_buffer_size_);
+    free_space_ += thread_alloc_size_;
+    CHECK(free_space_ <= free_space_end_ && "out of thread memory");
+    return t;
+  }
+
+  uptr free_space_;
+  uptr free_space_end_;
+  uptr ring_buffer_size_;
+  uptr thread_alloc_size_;
+
+  ThreadListHead free_list_;
+  ThreadListHead live_list_;
+  SpinMutex list_mutex_;
+
+  ThreadStats stats_;
+  SpinMutex stats_mutex_;
+};
+
+void InitThreadList(uptr storage, uptr size);
+HwasanThreadList &hwasanThreadList();
+
+} // namespace
diff --git a/libsanitizer/hwasan/hwasan_type_test.cpp b/libsanitizer/hwasan/hwasan_type_test.cpp
new file mode 100644
index 00000000000..8cff495bae1
--- /dev/null
+++ b/libsanitizer/hwasan/hwasan_type_test.cpp
@@ -0,0 +1,25 @@
+//===-- hwasan_type_test.cpp ------------------------------------*- C++ -*-===//
+//
+// 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 a part of HWAddressSanitizer.
+//
+// Compile-time tests of the internal type definitions.
+//===----------------------------------------------------------------------===//
+
+#include "interception/interception.h"
+#include "sanitizer_common/sanitizer_platform_limits_posix.h"
+#include "hwasan.h"
+#include <setjmp.h>
+
+#define CHECK_TYPE_SIZE_FITS(TYPE) \
+  COMPILER_CHECK(sizeof(__hw_##TYPE) <= sizeof(TYPE))
+
+#if HWASAN_WITH_INTERCEPTORS && defined(__aarch64__)
+CHECK_TYPE_SIZE_FITS(jmp_buf);
+CHECK_TYPE_SIZE_FITS(sigjmp_buf);
+#endif
diff --git a/libsanitizer/merge.sh b/libsanitizer/merge.sh
index 3f4f1629a22..95ded4f9634 100755
--- a/libsanitizer/merge.sh
+++ b/libsanitizer/merge.sh
@@ -71,6 +71,7 @@ merge lib/tsan/rtl tsan
 merge lib/sanitizer_common sanitizer_common
 merge lib/interception interception
 merge lib/ubsan ubsan
+merge lib/hwasan hwasan
 
 # Need to merge lib/builtins/assembly.h file:
 mkdir -p builtins