Refactor malloc common into distinct pieces.

The pieces:
- The malloc common shared by static and dynamic code (malloc_common.cpp).
- The code for shared libraries that includes any dlopen'ing
  (malloc_common_dynamic.cpp).
- The implementation of perfetto's heapprofd (malloc_heapprofd.cpp).

This makes it easier to see what's going on in the many different areas.
It should also make it easier to add the allocation capping option.

Other related changes:
- Update the unit tests for android_mallopt. All of the current options
  don't work on static binaries, so make sure that is reflected in the test.
- A few names changes to make sure that all code is consistent.

Test: Ran tests (malloc hooks/malloc debug/perfetto/bionic unit tests).
Change-Id: I0893bfbc0f83d82506fac5d1f37cf92fbdef6f59
diff --git a/libc/bionic/malloc_common.cpp b/libc/bionic/malloc_common.cpp
index b35aa27..80e82f7 100644
--- a/libc/bionic/malloc_common.cpp
+++ b/libc/bionic/malloc_common.cpp
@@ -41,69 +41,17 @@
 //                          get_malloc_leak_info.
 //   write_malloc_leak_info: Writes the leak info data to a file.
 
-#include <pthread.h>
-#include <stdatomic.h>
+#include <stdint.h>
 
-#include <private/bionic_defs.h>
 #include <private/bionic_config.h>
-#include <private/bionic_globals.h>
-#include <private/bionic_malloc.h>
-#include <private/bionic_malloc_dispatch.h>
 
-#if __has_feature(hwaddress_sanitizer)
-// FIXME: implement these in HWASan allocator.
-extern "C" int __sanitizer_iterate(uintptr_t base __unused, size_t size __unused,
-                                   void (*callback)(uintptr_t base, size_t size, void* arg) __unused,
-                                   void* arg __unused) {
-  return 0;
-}
+#include "malloc_common.h"
 
-extern "C" void __sanitizer_malloc_disable() {
-}
+// =============================================================================
+// Global variables instantations.
+// =============================================================================
 
-extern "C" void __sanitizer_malloc_enable() {
-}
-#include <sanitizer/hwasan_interface.h>
-#define Malloc(function)  __sanitizer_ ## function
-
-#else // __has_feature(hwaddress_sanitizer)
-#include "jemalloc.h"
-#define Malloc(function)  je_ ## function
-#endif
-
-template <typename T>
-static T* RemoveConst(const T* x) {
-  return const_cast<T*>(x);
-}
-
-// RemoveConst is a workaround for bug in current libcxx. Fix in
-// https://reviews.llvm.org/D47613
-#define atomic_load_explicit_const(obj, order) atomic_load_explicit(RemoveConst(obj), order)
-
-static constexpr MallocDispatch __libc_malloc_default_dispatch
-  __attribute__((unused)) = {
-    Malloc(calloc),
-    Malloc(free),
-    Malloc(mallinfo),
-    Malloc(malloc),
-    Malloc(malloc_usable_size),
-    Malloc(memalign),
-    Malloc(posix_memalign),
-#if defined(HAVE_DEPRECATED_MALLOC_FUNCS)
-    Malloc(pvalloc),
-#endif
-    Malloc(realloc),
-#if defined(HAVE_DEPRECATED_MALLOC_FUNCS)
-    Malloc(valloc),
-#endif
-    Malloc(iterate),
-    Malloc(malloc_disable),
-    Malloc(malloc_enable),
-    Malloc(mallopt),
-    Malloc(aligned_alloc),
-  };
-
-// Malloc hooks.
+// Malloc hooks globals.
 void* (*volatile __malloc_hook)(size_t, const void*);
 void* (*volatile __realloc_hook)(void*, size_t, const void*);
 void (*volatile __free_hook)(void*, const void*);
@@ -111,15 +59,11 @@
 
 // In a VM process, this is set to 1 after fork()ing out of zygote.
 int gMallocLeakZygoteChild = 0;
+// =============================================================================
 
 // =============================================================================
 // Allocation functions
 // =============================================================================
-static inline const MallocDispatch* GetDispatchTable() {
-  return atomic_load_explicit_const(&__libc_globals->current_dispatch_table,
-                                    memory_order_acquire);
-}
-
 extern "C" void* calloc(size_t n_elements, size_t elem_size) {
   auto dispatch_table = GetDispatchTable();
   if (__predict_false(dispatch_table != nullptr)) {
@@ -227,602 +171,7 @@
   return Malloc(valloc)(bytes);
 }
 #endif
-
-// We implement malloc debugging only in libc.so, so the code below
-// must be excluded if we compile this file for static libc.a
-#if !defined(LIBC_STATIC)
-
-#include <dlfcn.h>
-#include <fcntl.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <unistd.h>
-
-#include <async_safe/log.h>
-#include <sys/system_properties.h>
-
-extern "C" int __cxa_atexit(void (*func)(void *), void *arg, void *dso);
-
-static const char* HOOKS_SHARED_LIB = "libc_malloc_hooks.so";
-static const char* HOOKS_PROPERTY_ENABLE = "libc.debug.hooks.enable";
-static const char* HOOKS_ENV_ENABLE = "LIBC_HOOKS_ENABLE";
-
-static const char* DEBUG_SHARED_LIB = "libc_malloc_debug.so";
-static const char* DEBUG_PROPERTY_OPTIONS = "libc.debug.malloc.options";
-static const char* DEBUG_PROPERTY_PROGRAM = "libc.debug.malloc.program";
-static const char* DEBUG_ENV_OPTIONS = "LIBC_DEBUG_MALLOC_OPTIONS";
-
-static const char* HEAPPROFD_SHARED_LIB = "heapprofd_client.so";
-static const char* HEAPPROFD_PREFIX = "heapprofd";
-static const char* HEAPPROFD_PROPERTY_ENABLE = "heapprofd.enable";
-static const int HEAPPROFD_SIGNAL = __SIGRTMIN + 4;
-
-enum FunctionEnum : uint8_t {
-  FUNC_INITIALIZE,
-  FUNC_FINALIZE,
-  FUNC_GET_MALLOC_LEAK_INFO,
-  FUNC_FREE_MALLOC_LEAK_INFO,
-  FUNC_MALLOC_BACKTRACE,
-  FUNC_WRITE_LEAK_INFO,
-  FUNC_LAST,
-};
-static void* g_functions[FUNC_LAST];
-
-typedef void (*finalize_func_t)();
-typedef bool (*init_func_t)(const MallocDispatch*, int*, const char*);
-typedef void (*get_malloc_leak_info_func_t)(uint8_t**, size_t*, size_t*, size_t*, size_t*);
-typedef void (*free_malloc_leak_info_func_t)(uint8_t*);
-typedef bool (*write_malloc_leak_info_func_t)(FILE*);
-typedef ssize_t (*malloc_backtrace_func_t)(void*, uintptr_t*, size_t);
-
 // =============================================================================
-// Log functions
-// =============================================================================
-#define error_log(format, ...)  \
-    async_safe_format_log(ANDROID_LOG_ERROR, "libc", (format), ##__VA_ARGS__ )
-#define info_log(format, ...)  \
-    async_safe_format_log(ANDROID_LOG_INFO, "libc", (format), ##__VA_ARGS__ )
-// =============================================================================
-
-// In a Zygote child process, this is set to true if profiling of this process
-// is allowed. Note that this set at a later time than the above
-// gMallocLeakZygoteChild. The latter is set during the fork (while still in
-// zygote's SELinux domain). While this bit is set after the child is
-// specialized (and has transferred SELinux domains if applicable).
-static _Atomic bool gMallocZygoteChildProfileable = false;
-
-// =============================================================================
-// Exported for use by ddms.
-// =============================================================================
-
-// Retrieve native heap information.
-//
-// "*info" is set to a buffer we allocate
-// "*overall_size" is set to the size of the "info" buffer
-// "*info_size" is set to the size of a single entry
-// "*total_memory" is set to the sum of all allocations we're tracking; does
-//   not include heap overhead
-// "*backtrace_size" is set to the maximum number of entries in the back trace
-extern "C" void get_malloc_leak_info(uint8_t** info, size_t* overall_size,
-    size_t* info_size, size_t* total_memory, size_t* backtrace_size) {
-  void* func = g_functions[FUNC_GET_MALLOC_LEAK_INFO];
-  if (func == nullptr) {
-    return;
-  }
-  reinterpret_cast<get_malloc_leak_info_func_t>(func)(info, overall_size, info_size, total_memory,
-                                                      backtrace_size);
-}
-
-extern "C" void free_malloc_leak_info(uint8_t* info) {
-  void* func = g_functions[FUNC_FREE_MALLOC_LEAK_INFO];
-  if (func == nullptr) {
-    return;
-  }
-  reinterpret_cast<free_malloc_leak_info_func_t>(func)(info);
-}
-
-extern "C" void write_malloc_leak_info(FILE* fp) {
-  if (fp == nullptr) {
-    error_log("write_malloc_leak_info called with a nullptr");
-    return;
-  }
-
-  void* func = g_functions[FUNC_WRITE_LEAK_INFO];
-  bool written = false;
-  if (func != nullptr) {
-    written = reinterpret_cast<write_malloc_leak_info_func_t>(func)(fp);
-  }
-
-  if (!written) {
-    fprintf(fp, "Native heap dump not available. To enable, run these commands (requires root):\n");
-    fprintf(fp, "# adb shell stop\n");
-    fprintf(fp, "# adb shell setprop libc.debug.malloc.options backtrace\n");
-    fprintf(fp, "# adb shell start\n");
-  }
-}
-
-// =============================================================================
-
-template<typename FunctionType>
-static bool InitMallocFunction(void* malloc_impl_handler, FunctionType* func, const char* prefix, const char* suffix) {
-  char symbol[128];
-  snprintf(symbol, sizeof(symbol), "%s_%s", prefix, suffix);
-  *func = reinterpret_cast<FunctionType>(dlsym(malloc_impl_handler, symbol));
-  if (*func == nullptr) {
-    error_log("%s: dlsym(\"%s\") failed", getprogname(), symbol);
-    return false;
-  }
-  return true;
-}
-
-static bool InitMallocFunctions(void* impl_handler, MallocDispatch* table, const char* prefix) {
-  if (!InitMallocFunction<MallocFree>(impl_handler, &table->free, prefix, "free")) {
-    return false;
-  }
-  if (!InitMallocFunction<MallocCalloc>(impl_handler, &table->calloc, prefix, "calloc")) {
-    return false;
-  }
-  if (!InitMallocFunction<MallocMallinfo>(impl_handler, &table->mallinfo, prefix, "mallinfo")) {
-    return false;
-  }
-  if (!InitMallocFunction<MallocMallopt>(impl_handler, &table->mallopt, prefix, "mallopt")) {
-    return false;
-  }
-  if (!InitMallocFunction<MallocMalloc>(impl_handler, &table->malloc, prefix, "malloc")) {
-    return false;
-  }
-  if (!InitMallocFunction<MallocMallocUsableSize>(impl_handler, &table->malloc_usable_size, prefix,
-                                                  "malloc_usable_size")) {
-    return false;
-  }
-  if (!InitMallocFunction<MallocMemalign>(impl_handler, &table->memalign, prefix, "memalign")) {
-    return false;
-  }
-  if (!InitMallocFunction<MallocPosixMemalign>(impl_handler, &table->posix_memalign, prefix,
-                                               "posix_memalign")) {
-    return false;
-  }
-  if (!InitMallocFunction<MallocAlignedAlloc>(impl_handler, &table->aligned_alloc,
-                                              prefix, "aligned_alloc")) {
-    return false;
-  }
-  if (!InitMallocFunction<MallocRealloc>(impl_handler, &table->realloc, prefix, "realloc")) {
-    return false;
-  }
-  if (!InitMallocFunction<MallocIterate>(impl_handler, &table->iterate, prefix, "iterate")) {
-    return false;
-  }
-  if (!InitMallocFunction<MallocMallocDisable>(impl_handler, &table->malloc_disable, prefix,
-                                               "malloc_disable")) {
-    return false;
-  }
-  if (!InitMallocFunction<MallocMallocEnable>(impl_handler, &table->malloc_enable, prefix,
-                                              "malloc_enable")) {
-    return false;
-  }
-#if defined(HAVE_DEPRECATED_MALLOC_FUNCS)
-  if (!InitMallocFunction<MallocPvalloc>(impl_handler, &table->pvalloc, prefix, "pvalloc")) {
-    return false;
-  }
-  if (!InitMallocFunction<MallocValloc>(impl_handler, &table->valloc, prefix, "valloc")) {
-    return false;
-  }
-#endif
-
-  return true;
-}
-
-static void MallocFiniImpl(void*) {
-  // Our BSD stdio implementation doesn't close the standard streams,
-  // it only flushes them. Other unclosed FILE*s will show up as
-  // malloc leaks, but to avoid the standard streams showing up in
-  // leak reports, close them here.
-  fclose(stdin);
-  fclose(stdout);
-  fclose(stderr);
-
-  reinterpret_cast<finalize_func_t>(g_functions[FUNC_FINALIZE])();
-}
-
-static bool CheckLoadMallocHooks(char** options) {
-  char* env = getenv(HOOKS_ENV_ENABLE);
-  if ((env == nullptr || env[0] == '\0' || env[0] == '0') &&
-    (__system_property_get(HOOKS_PROPERTY_ENABLE, *options) == 0 || *options[0] == '\0' || *options[0] == '0')) {
-    return false;
-  }
-  *options = nullptr;
-  return true;
-}
-
-static bool CheckLoadMallocDebug(char** options) {
-  // If DEBUG_MALLOC_ENV_OPTIONS is set then it overrides the system properties.
-  char* env = getenv(DEBUG_ENV_OPTIONS);
-  if (env == nullptr || env[0] == '\0') {
-    if (__system_property_get(DEBUG_PROPERTY_OPTIONS, *options) == 0 || *options[0] == '\0') {
-      return false;
-    }
-
-    // Check to see if only a specific program should have debug malloc enabled.
-    char program[PROP_VALUE_MAX];
-    if (__system_property_get(DEBUG_PROPERTY_PROGRAM, program) != 0 &&
-        strstr(getprogname(), program) == nullptr) {
-      return false;
-    }
-  } else {
-    *options = env;
-  }
-  return true;
-}
-
-static bool GetHeapprofdProgramProperty(char* data, size_t size) {
-  constexpr char prefix[] = "heapprofd.enable.";
-  // - 1 to skip nullbyte, which we will write later.
-  constexpr size_t prefix_size = sizeof(prefix) - 1;
-  if (size < prefix_size) {
-    error_log("%s: Overflow constructing heapprofd property", getprogname());
-    return false;
-  }
-  memcpy(data, prefix, prefix_size);
-
-  int fd = open("/proc/self/cmdline", O_RDONLY | O_CLOEXEC);
-  if (fd == -1) {
-    error_log("%s: Failed to open /proc/self/cmdline", getprogname());
-    return false;
-  }
-  char cmdline[128];
-  ssize_t rd = read(fd, cmdline, sizeof(cmdline) - 1);
-  close(fd);
-  if (rd == -1) {
-    error_log("%s: Failed to read /proc/self/cmdline", getprogname());
-    return false;
-  }
-  cmdline[rd] = '\0';
-  char* first_arg = static_cast<char*>(memchr(cmdline, '\0', rd));
-  if (first_arg == nullptr || first_arg == cmdline + size - 1) {
-    error_log("%s: Overflow reading cmdline", getprogname());
-    return false;
-  }
-  // For consistency with what we do with Java app cmdlines, trim everything
-  // after the @ sign of the first arg.
-  char* first_at = static_cast<char*>(memchr(cmdline, '@', rd));
-  if (first_at != nullptr && first_at < first_arg) {
-    *first_at = '\0';
-    first_arg = first_at;
-  }
-
-  char* start = static_cast<char*>(memrchr(cmdline, '/', first_arg - cmdline));
-  if (start == first_arg) {
-    // The first argument ended in a slash.
-    error_log("%s: cmdline ends in /", getprogname());
-    return false;
-  } else if (start == nullptr) {
-    start = cmdline;
-  } else {
-    // Skip the /.
-    start++;
-  }
-
-  size_t name_size = static_cast<size_t>(first_arg - start);
-  if (name_size >= size - prefix_size) {
-    error_log("%s: overflow constructing heapprofd property.", getprogname());
-    return false;
-  }
-  // + 1 to also copy the trailing null byte.
-  memcpy(data + prefix_size, start, name_size + 1);
-  return true;
-}
-
-static bool CheckLoadHeapprofd() {
-  // First check for heapprofd.enable. If it is set to "all", enable
-  // heapprofd for all processes. Otherwise, check heapprofd.enable.${prog},
-  // if it is set and not 0, enable heap profiling for this process.
-  char property_value[PROP_VALUE_MAX];
-  if (__system_property_get(HEAPPROFD_PROPERTY_ENABLE, property_value) == 0) {
-    return false;
-  }
-  if (strcmp(property_value, "all") == 0) {
-    return true;
-  }
-
-  char program_property[128];
-  if (!GetHeapprofdProgramProperty(program_property,
-                                   sizeof(program_property))) {
-    return false;
-  }
-  if (__system_property_get(program_property, property_value) == 0) {
-    return false;
-  }
-  return program_property[0] != '\0';
-}
-
-static void ClearGlobalFunctions() {
-  for (size_t i = 0; i < FUNC_LAST; i++) {
-    g_functions[i] = nullptr;
-  }
-}
-
-static bool InitSharedLibrary(void* impl_handle, const char* shared_lib, const char* prefix, MallocDispatch* dispatch_table) {
-  static constexpr const char* names[] = {
-    "initialize",
-    "finalize",
-    "get_malloc_leak_info",
-    "free_malloc_leak_info",
-    "malloc_backtrace",
-    "write_malloc_leak_info",
-  };
-  for (size_t i = 0; i < FUNC_LAST; i++) {
-    char symbol[128];
-    snprintf(symbol, sizeof(symbol), "%s_%s", prefix, names[i]);
-    g_functions[i] = dlsym(impl_handle, symbol);
-    if (g_functions[i] == nullptr) {
-      error_log("%s: %s routine not found in %s", getprogname(), symbol, shared_lib);
-      ClearGlobalFunctions();
-      return false;
-    }
-  }
-
-  if (!InitMallocFunctions(impl_handle, dispatch_table, prefix)) {
-    ClearGlobalFunctions();
-    return false;
-  }
-  return true;
-}
-
-static void* LoadSharedLibrary(const char* shared_lib, const char* prefix, MallocDispatch* dispatch_table) {
-  void* impl_handle = dlopen(shared_lib, RTLD_NOW | RTLD_LOCAL);
-  if (impl_handle == nullptr) {
-    error_log("%s: Unable to open shared library %s: %s", getprogname(), shared_lib, dlerror());
-    return nullptr;
-  }
-
-  if (!InitSharedLibrary(impl_handle, shared_lib, prefix, dispatch_table)) {
-    dlclose(impl_handle);
-    impl_handle = nullptr;
-  }
-
-  return impl_handle;
-}
-
-// The handle returned by dlopen when previously loading the heapprofd
-// hooks. nullptr if they had not been loaded before.
-static _Atomic (void*) g_heapprofd_handle = nullptr;
-
-static void InstallHooks(libc_globals* globals, const char* options,
-                          const char* prefix, const char* shared_lib) {
-  void* impl_handle = atomic_load(&g_heapprofd_handle);
-  bool reusing_handle = impl_handle != nullptr;
-  if (reusing_handle) {
-    if (!InitSharedLibrary(impl_handle, shared_lib, prefix, &globals->malloc_dispatch_table)) {
-      return;
-    }
-  } else {
-    impl_handle = LoadSharedLibrary(shared_lib, prefix, &globals->malloc_dispatch_table);
-    if (impl_handle == nullptr) {
-      return;
-    }
-  }
-  init_func_t init_func = reinterpret_cast<init_func_t>(g_functions[FUNC_INITIALIZE]);
-  if (!init_func(&__libc_malloc_default_dispatch, &gMallocLeakZygoteChild, options)) {
-    error_log("%s: failed to enable malloc %s", getprogname(), prefix);
-    if (!reusing_handle) {
-      // We should not close if we are re-using an old handle, as we cannot be
-      // sure other threads are not currently in the hooks.
-      dlclose(impl_handle);
-    }
-    ClearGlobalFunctions();
-    return;
-  }
-
-  // Do a pointer swap so that all of the functions become valid at once to
-  // avoid any initialization order problems.
-  atomic_store(&globals->current_dispatch_table, &globals->malloc_dispatch_table);
-
-  atomic_store(&g_heapprofd_handle, impl_handle);
-
-  info_log("%s: malloc %s enabled", getprogname(), prefix);
-
-  // Use atexit to trigger the cleanup function. This avoids a problem
-  // where another atexit function is used to cleanup allocated memory,
-  // but the finalize function was already called. This particular error
-  // seems to be triggered by a zygote spawned process calling exit.
-  int ret_value = __cxa_atexit(MallocFiniImpl, nullptr, nullptr);
-  if (ret_value != 0) {
-    error_log("failed to set atexit cleanup function: %d", ret_value);
-  }
-}
-
-// The logic for triggering heapprofd (at runtime) is as follows:
-// 1. HEAPPROFD_SIGNAL is received by the process, entering the
-//    MaybeInstallInitHeapprofdHook signal handler.
-// 2. If the initialization is not already in flight
-//    (g_heapprofd_init_in_progress is false), the malloc hook is set to
-//    point at InitHeapprofdHook, and g_heapprofd_init_in_progress is set to
-//    true.
-// 3. The next malloc call enters InitHeapprofdHook, which removes the malloc
-//    hook, and spawns a detached pthread to run the InitHeapprofd task.
-//    (g_heapprofd_init_hook_installed atomic is used to perform this once.)
-// 4. InitHeapprofd, on a dedicated pthread, loads the heapprofd client library,
-//    installs the full set of heapprofd hooks, and invokes the client's
-//    initializer. The dedicated pthread then terminates.
-// 5. g_heapprofd_init_in_progress and g_heapprofd_init_hook_installed are
-//    reset to false such that heapprofd can be reinitialized. Reinitialization
-//    means that a new profiling session is started, and any still active is
-//    torn down.
-//
-// The incremental hooking and a dedicated task thread are used since we cannot
-// do heavy work within a signal handler, or when blocking a malloc invocation.
-
-static _Atomic bool g_heapprofd_init_in_progress = false;
-static _Atomic bool g_heapprofd_init_hook_installed = false;
-
-extern "C" void MaybeInstallInitHeapprofdHook(int);
-
-// Initializes memory allocation framework once per process.
-static void MallocInitImpl(libc_globals* globals) {
-  struct sigaction action = {};
-  action.sa_handler = MaybeInstallInitHeapprofdHook;
-  sigaction(HEAPPROFD_SIGNAL, &action, nullptr);
-
-  const char* prefix;
-  const char* shared_lib;
-  char prop[PROP_VALUE_MAX];
-  char* options = prop;
-  // Prefer malloc debug since it existed first and is a more complete
-  // malloc interceptor than the hooks.
-  if (CheckLoadMallocDebug(&options)) {
-    prefix = "debug";
-    shared_lib = DEBUG_SHARED_LIB;
-  } else if (CheckLoadMallocHooks(&options)) {
-    prefix = "hooks";
-    shared_lib = HOOKS_SHARED_LIB;
-  } else if (CheckLoadHeapprofd()) {
-    prefix = "heapprofd";
-    shared_lib = HEAPPROFD_SHARED_LIB;
-  } else {
-    return;
-  }
-  if (!atomic_exchange(&g_heapprofd_init_in_progress, true)) {
-    InstallHooks(globals, options, prefix, shared_lib);
-    atomic_store(&g_heapprofd_init_in_progress, false);
-  }
-}
-
-// Initializes memory allocation framework.
-// This routine is called from __libc_init routines in libc_init_dynamic.cpp.
-__BIONIC_WEAK_FOR_NATIVE_BRIDGE
-__LIBC_HIDDEN__ void __libc_init_malloc(libc_globals* globals) {
-  MallocInitImpl(globals);
-}
-
-static void* InitHeapprofd(void*) {
-  __libc_globals.mutate([](libc_globals* globals) {
-    InstallHooks(globals, nullptr, HEAPPROFD_PREFIX, HEAPPROFD_SHARED_LIB);
-  });
-  atomic_store(&g_heapprofd_init_in_progress, false);
-  // Allow to install hook again to re-initialize heap profiling after the
-  // current session finished.
-  atomic_store(&g_heapprofd_init_hook_installed, false);
-  return nullptr;
-}
-
-static void* InitHeapprofdHook(size_t bytes) {
-  if (!atomic_exchange(&g_heapprofd_init_hook_installed, true)) {
-    __libc_globals.mutate([](libc_globals* globals) {
-      atomic_store(&globals->current_dispatch_table, nullptr);
-    });
-
-    pthread_t thread_id;
-    if (pthread_create(&thread_id, nullptr, InitHeapprofd, nullptr) == -1)
-      error_log("%s: heapprofd: failed to pthread_create.", getprogname());
-    else if (pthread_detach(thread_id) == -1)
-      error_log("%s: heapprofd: failed to pthread_detach", getprogname());
-    if (pthread_setname_np(thread_id, "heapprofdinit") == -1)
-      error_log("%s: heapprod: failed to pthread_setname_np", getprogname());
-  }
-  return Malloc(malloc)(bytes);
-}
-
-static constexpr MallocDispatch __heapprofd_dispatch
-  __attribute__((unused)) = {
-    Malloc(calloc),
-    Malloc(free),
-    Malloc(mallinfo),
-    InitHeapprofdHook,
-    Malloc(malloc_usable_size),
-    Malloc(memalign),
-    Malloc(posix_memalign),
-#if defined(HAVE_DEPRECATED_MALLOC_FUNCS)
-    Malloc(pvalloc),
-#endif
-    Malloc(realloc),
-#if defined(HAVE_DEPRECATED_MALLOC_FUNCS)
-    Malloc(valloc),
-#endif
-    Malloc(iterate),
-    Malloc(malloc_disable),
-    Malloc(malloc_enable),
-    Malloc(mallopt),
-    Malloc(aligned_alloc),
-  };
-
-extern "C" void MaybeInstallInitHeapprofdHook(int) {
-  // Zygote child processes must be marked profileable.
-  if (gMallocLeakZygoteChild &&
-      !atomic_load_explicit_const(&gMallocZygoteChildProfileable, memory_order_acquire)) {
-    return;
-  }
-
-  if (!atomic_exchange(&g_heapprofd_init_in_progress, true)) {
-    __libc_globals.mutate([](libc_globals* globals) {
-      atomic_store(&globals->current_dispatch_table, &__heapprofd_dispatch);
-    });
-  }
-}
-
-#endif  // !LIBC_STATIC
-
-// =============================================================================
-// Platform-internal mallopt variant.
-// =============================================================================
-
-#if !defined(LIBC_STATIC)
-bool MallocDispatchReset() {
-  if (!atomic_exchange(&g_heapprofd_init_in_progress, true)) {
-    __libc_globals.mutate([](libc_globals* globals) {
-      atomic_store(&globals->current_dispatch_table, nullptr);
-    });
-    atomic_store(&g_heapprofd_init_in_progress, false);
-    return true;
-  }
-  errno = EAGAIN;
-  return false;
-}
-
-// Marks this process as a profileable zygote child.
-bool HandleInitZygoteChildProfiling() {
-  atomic_store_explicit(&gMallocZygoteChildProfileable, true,
-                        memory_order_release);
-
-  // Conditionally start "from startup" profiling.
-  if (CheckLoadHeapprofd()) {
-    // Directly call the signal handler (will correctly guard against
-    // concurrent signal delivery).
-    MaybeInstallInitHeapprofdHook(HEAPPROFD_SIGNAL);
-  }
-  return true;
-}
-
-#else
-
-bool MallocDispatchReset() {
-  return true;
-}
-
-bool HandleInitZygoteChildProfiling() {
-  return true;
-}
-
-#endif  // !defined(LIBC_STATIC)
-
-bool android_mallopt(int opcode, void* arg, size_t arg_size) {
-  if (opcode == M_INIT_ZYGOTE_CHILD_PROFILING) {
-    if (arg != nullptr || arg_size != 0) {
-      errno = EINVAL;
-      return false;
-    }
-    return HandleInitZygoteChildProfiling();
-  }
-  if (opcode == M_RESET_HOOKS) {
-    if (arg != nullptr || arg_size != 0) {
-      errno = EINVAL;
-      return false;
-    }
-    return MallocDispatchReset();
-  }
-
-  errno = ENOTSUP;
-  return false;
-}
 
 // =============================================================================
 // Exported for use by libmemunreachable.
@@ -858,16 +207,36 @@
   return Malloc(malloc_enable)();
 }
 
-#ifndef LIBC_STATIC
-extern "C" ssize_t malloc_backtrace(void* pointer, uintptr_t* frames, size_t frame_count) {
-  void* func = g_functions[FUNC_MALLOC_BACKTRACE];
-  if (func == nullptr) {
-    return 0;
-  }
-  return reinterpret_cast<malloc_backtrace_func_t>(func)(pointer, frames, frame_count);
-}
-#else
+#if defined(LIBC_STATIC)
 extern "C" ssize_t malloc_backtrace(void*, uintptr_t*, size_t) {
   return 0;
 }
 #endif
+
+#if __has_feature(hwaddress_sanitizer)
+// FIXME: implement these in HWASan allocator.
+extern "C" int __sanitizer_iterate(uintptr_t base __unused, size_t size __unused,
+                                   void (*callback)(uintptr_t base, size_t size, void* arg) __unused,
+                                   void* arg __unused) {
+  return 0;
+}
+
+extern "C" void __sanitizer_malloc_disable() {
+}
+
+extern "C" void __sanitizer_malloc_enable() {
+}
+#endif
+// =============================================================================
+
+// =============================================================================
+// Platform-internal mallopt variant.
+// =============================================================================
+#if defined(LIBC_STATIC)
+extern "C" bool android_mallopt(int, void*, size_t) {
+  // There are no options supported on static executables.
+  errno = ENOTSUP;
+  return false;
+}
+#endif
+// =============================================================================