Put all allocation functions into dispatch table.

Implement these new functions for all of the debug malloc types.

Fix a number of bugs in the debug malloc functions related to overflow
conditions.
Fix a bug in dlpvalloc due to an overflow condition.

Fix various other bugs in the debug malloc functions.

Add new tests for malloc functions.

Bug: 11225066

Change-Id: Idf50f389603e2157645565bc15cd9365eec2e9dd
diff --git a/libc/bionic/malloc_debug_common.cpp b/libc/bionic/malloc_debug_common.cpp
index 77ec080..6677c22 100644
--- a/libc/bionic/malloc_debug_common.cpp
+++ b/libc/bionic/malloc_debug_common.cpp
@@ -26,19 +26,17 @@
  * SUCH DAMAGE.
  */
 
-/*
- * Contains definition of structures, global variables, and implementation of
- * routines that are used by malloc leak detection code and other components in
- * the system. The trick is that some components expect these data and
- * routines to be defined / implemented in libc.so library, regardless
- * whether or not MALLOC_LEAK_CHECK macro is defined. To make things even
- * more tricky, malloc leak detection code, implemented in
- * libc_malloc_debug.so also requires access to these variables and routines
- * (to fill allocation entry hash table, for example). So, all relevant
- * variables and routines are defined / implemented here and exported
- * to all, leak detection code and other components via dynamic (libc.so),
- * or static (libc.a) linking.
- */
+// Contains definition of structures, global variables, and implementation of
+// routines that are used by malloc leak detection code and other components in
+// the system. The trick is that some components expect these data and
+// routines to be defined / implemented in libc.so library, regardless
+// whether or not MALLOC_LEAK_CHECK macro is defined. To make things even
+// more tricky, malloc leak detection code, implemented in
+// libc_malloc_debug.so also requires access to these variables and routines
+// (to fill allocation entry hash table, for example). So, all relevant
+// variables and routines are defined / implemented here and exported
+// to all, leak detection code and other components via dynamic (libc.so),
+// or static (libc.a) linking.
 
 #include "malloc_debug_common.h"
 
@@ -56,7 +54,16 @@
 // Support for malloc debugging.
 // Table for dispatching malloc calls, initialized with default dispatchers.
 static const MallocDebug __libc_malloc_default_dispatch __attribute__((aligned(32))) = {
-  Malloc(malloc), Malloc(free), Malloc(calloc), Malloc(realloc), Malloc(memalign), Malloc(malloc_usable_size),
+  Malloc(calloc),
+  Malloc(free),
+  Malloc(mallinfo),
+  Malloc(malloc),
+  Malloc(malloc_usable_size),
+  Malloc(memalign),
+  Malloc(posix_memalign),
+  Malloc(pvalloc),
+  Malloc(realloc),
+  Malloc(valloc),
 };
 
 // Selector of dispatch table to use for dispatching malloc calls.
@@ -97,176 +104,174 @@
 // =============================================================================
 
 static int hash_entry_compare(const void* arg1, const void* arg2) {
-    int result;
+  int result;
 
-    const HashEntry* e1 = *static_cast<HashEntry* const*>(arg1);
-    const HashEntry* e2 = *static_cast<HashEntry* const*>(arg2);
+  const HashEntry* e1 = *static_cast<HashEntry* const*>(arg1);
+  const HashEntry* e2 = *static_cast<HashEntry* const*>(arg2);
 
-    // if one or both arg pointers are null, deal gracefully
-    if (e1 == NULL) {
-        result = (e2 == NULL) ? 0 : 1;
-    } else if (e2 == NULL) {
-        result = -1;
+  // if one or both arg pointers are null, deal gracefully
+  if (e1 == NULL) {
+    result = (e2 == NULL) ? 0 : 1;
+  } else if (e2 == NULL) {
+    result = -1;
+  } else {
+    size_t nbAlloc1 = e1->allocations;
+    size_t nbAlloc2 = e2->allocations;
+    size_t size1 = e1->size & ~SIZE_FLAG_MASK;
+    size_t size2 = e2->size & ~SIZE_FLAG_MASK;
+    size_t alloc1 = nbAlloc1 * size1;
+    size_t alloc2 = nbAlloc2 * size2;
+
+    // sort in descending order by:
+    // 1) total size
+    // 2) number of allocations
+    //
+    // This is used for sorting, not determination of equality, so we don't
+    // need to compare the bit flags.
+    if (alloc1 > alloc2) {
+      result = -1;
+    } else if (alloc1 < alloc2) {
+      result = 1;
     } else {
-        size_t nbAlloc1 = e1->allocations;
-        size_t nbAlloc2 = e2->allocations;
-        size_t size1 = e1->size & ~SIZE_FLAG_MASK;
-        size_t size2 = e2->size & ~SIZE_FLAG_MASK;
-        size_t alloc1 = nbAlloc1 * size1;
-        size_t alloc2 = nbAlloc2 * size2;
-
-        // sort in descending order by:
-        // 1) total size
-        // 2) number of allocations
-        //
-        // This is used for sorting, not determination of equality, so we don't
-        // need to compare the bit flags.
-        if (alloc1 > alloc2) {
-            result = -1;
-        } else if (alloc1 < alloc2) {
-            result = 1;
-        } else {
-            if (nbAlloc1 > nbAlloc2) {
-                result = -1;
-            } else if (nbAlloc1 < nbAlloc2) {
-                result = 1;
-            } else {
-                result = 0;
-            }
-        }
+      if (nbAlloc1 > nbAlloc2) {
+        result = -1;
+      } else if (nbAlloc1 < nbAlloc2) {
+        result = 1;
+      } else {
+        result = 0;
+      }
     }
-    return result;
+  }
+  return result;
 }
 
-/*
- * Retrieve native heap information.
- *
- * "*info" is set to a buffer we allocate
- * "*overallSize" is set to the size of the "info" buffer
- * "*infoSize" is set to the size of a single entry
- * "*totalMemory" is set to the sum of all allocations we're tracking; does
- *   not include heap overhead
- * "*backtraceSize" is set to the maximum number of entries in the back trace
- */
+// Retrieve native heap information.
+//
+// "*info" is set to a buffer we allocate
+// "*overallSize" is set to the size of the "info" buffer
+// "*infoSize" is set to the size of a single entry
+// "*totalMemory" is set to the sum of all allocations we're tracking; does
+//   not include heap overhead
+// "*backtraceSize" is set to the maximum number of entries in the back trace
 
+// =============================================================================
 // Exported for use by ddms.
+// =============================================================================
 extern "C" void get_malloc_leak_info(uint8_t** info, size_t* overallSize,
-        size_t* infoSize, size_t* totalMemory, size_t* backtraceSize) {
-    // don't do anything if we have invalid arguments
-    if (info == NULL || overallSize == NULL || infoSize == NULL ||
-            totalMemory == NULL || backtraceSize == NULL) {
-        return;
+    size_t* infoSize, size_t* totalMemory, size_t* backtraceSize) {
+  // Don't do anything if we have invalid arguments.
+  if (info == NULL || overallSize == NULL || infoSize == NULL ||
+    totalMemory == NULL || backtraceSize == NULL) {
+    return;
+  }
+  *totalMemory = 0;
+
+  ScopedPthreadMutexLocker locker(&g_hash_table.lock);
+  if (g_hash_table.count == 0) {
+    *info = NULL;
+    *overallSize = 0;
+    *infoSize = 0;
+    *backtraceSize = 0;
+    return;
+  }
+
+  HashEntry** list = static_cast<HashEntry**>(Malloc(malloc)(sizeof(void*) * g_hash_table.count));
+
+  // Get the entries into an array to be sorted.
+  size_t index = 0;
+  for (size_t i = 0 ; i < HASHTABLE_SIZE ; ++i) {
+    HashEntry* entry = g_hash_table.slots[i];
+    while (entry != NULL) {
+      list[index] = entry;
+      *totalMemory = *totalMemory + ((entry->size & ~SIZE_FLAG_MASK) * entry->allocations);
+      index++;
+      entry = entry->next;
     }
-    *totalMemory = 0;
+  }
 
-    ScopedPthreadMutexLocker locker(&g_hash_table.lock);
+  // XXX: the protocol doesn't allow variable size for the stack trace (yet)
+  *infoSize = (sizeof(size_t) * 2) + (sizeof(uintptr_t) * BACKTRACE_SIZE);
+  *overallSize = *infoSize * g_hash_table.count;
+  *backtraceSize = BACKTRACE_SIZE;
 
-    if (g_hash_table.count == 0) {
-        *info = NULL;
-        *overallSize = 0;
-        *infoSize = 0;
-        *backtraceSize = 0;
-        return;
-    }
-
-    HashEntry** list = static_cast<HashEntry**>(Malloc(malloc)(sizeof(void*) * g_hash_table.count));
-
-    // get the entries into an array to be sorted
-    int index = 0;
-    for (size_t i = 0 ; i < HASHTABLE_SIZE ; ++i) {
-        HashEntry* entry = g_hash_table.slots[i];
-        while (entry != NULL) {
-            list[index] = entry;
-            *totalMemory = *totalMemory +
-                ((entry->size & ~SIZE_FLAG_MASK) * entry->allocations);
-            index++;
-            entry = entry->next;
-        }
-    }
-
-    // XXX: the protocol doesn't allow variable size for the stack trace (yet)
-    *infoSize = (sizeof(size_t) * 2) + (sizeof(uintptr_t) * BACKTRACE_SIZE);
-    *overallSize = *infoSize * g_hash_table.count;
-    *backtraceSize = BACKTRACE_SIZE;
-
-    // now get a byte array big enough for this
-    *info = static_cast<uint8_t*>(Malloc(malloc)(*overallSize));
-
-    if (*info == NULL) {
-        *overallSize = 0;
-        Malloc(free)(list);
-        return;
-    }
-
-    qsort(list, g_hash_table.count, sizeof(void*), hash_entry_compare);
-
-    uint8_t* head = *info;
-    const int count = g_hash_table.count;
-    for (int i = 0 ; i < count ; ++i) {
-        HashEntry* entry = list[i];
-        size_t entrySize = (sizeof(size_t) * 2) + (sizeof(uintptr_t) * entry->numEntries);
-        if (entrySize < *infoSize) {
-            /* we're writing less than a full entry, clear out the rest */
-            memset(head + entrySize, 0, *infoSize - entrySize);
-        } else {
-            /* make sure the amount we're copying doesn't exceed the limit */
-            entrySize = *infoSize;
-        }
-        memcpy(head, &(entry->size), entrySize);
-        head += *infoSize;
-    }
-
+  // now get a byte array big enough for this
+  *info = static_cast<uint8_t*>(Malloc(malloc)(*overallSize));
+  if (*info == NULL) {
+    *overallSize = 0;
     Malloc(free)(list);
+    return;
+  }
+
+  qsort(list, g_hash_table.count, sizeof(void*), hash_entry_compare);
+
+  uint8_t* head = *info;
+  const size_t count = g_hash_table.count;
+  for (size_t i = 0 ; i < count ; ++i) {
+    HashEntry* entry = list[i];
+    size_t entrySize = (sizeof(size_t) * 2) + (sizeof(uintptr_t) * entry->numEntries);
+    if (entrySize < *infoSize) {
+      // We're writing less than a full entry, clear out the rest.
+      memset(head + entrySize, 0, *infoSize - entrySize);
+    } else {
+      // Make sure the amount we're copying doesn't exceed the limit.
+      entrySize = *infoSize;
+    }
+    memcpy(head, &(entry->size), entrySize);
+    head += *infoSize;
+  }
+
+  Malloc(free)(list);
 }
 
-// Exported for use by ddms.
 extern "C" void free_malloc_leak_info(uint8_t* info) {
-    Malloc(free)(info);
+  Malloc(free)(info);
 }
 
-extern "C" struct mallinfo mallinfo() {
-    return Malloc(mallinfo)();
-}
-
-extern "C" void* valloc(size_t bytes) {
-    return Malloc(valloc)(bytes);
-}
-
-extern "C" void* pvalloc(size_t bytes) {
-    return Malloc(pvalloc)(bytes);
-}
-
-extern "C" int posix_memalign(void** memptr, size_t alignment, size_t size) {
-    return Malloc(posix_memalign)(memptr, alignment, size);
-}
-
-extern "C" void* malloc(size_t bytes) {
-    return __libc_malloc_dispatch->malloc(bytes);
+// =============================================================================
+// Allocation functions
+// =============================================================================
+extern "C" void* calloc(size_t n_elements, size_t elem_size) {
+  return __libc_malloc_dispatch->calloc(n_elements, elem_size);
 }
 
 extern "C" void free(void* mem) {
-    __libc_malloc_dispatch->free(mem);
+  __libc_malloc_dispatch->free(mem);
 }
 
-extern "C" void* calloc(size_t n_elements, size_t elem_size) {
-    return __libc_malloc_dispatch->calloc(n_elements, elem_size);
+extern "C" struct mallinfo mallinfo() {
+  return __libc_malloc_dispatch->mallinfo();
 }
 
-extern "C" void* realloc(void* oldMem, size_t bytes) {
-    return __libc_malloc_dispatch->realloc(oldMem, bytes);
-}
-
-extern "C" void* memalign(size_t alignment, size_t bytes) {
-    return __libc_malloc_dispatch->memalign(alignment, bytes);
+extern "C" void* malloc(size_t bytes) {
+  return __libc_malloc_dispatch->malloc(bytes);
 }
 
 extern "C" size_t malloc_usable_size(const void* mem) {
-    return __libc_malloc_dispatch->malloc_usable_size(mem);
+  return __libc_malloc_dispatch->malloc_usable_size(mem);
 }
 
-/* We implement malloc debugging only in libc.so, so code below
- * must be excluded if we compile this file for static libc.a
- */
+extern "C" void* memalign(size_t alignment, size_t bytes) {
+  return __libc_malloc_dispatch->memalign(alignment, bytes);
+}
+
+extern "C" int posix_memalign(void** memptr, size_t alignment, size_t size) {
+  return __libc_malloc_dispatch->posix_memalign(memptr, alignment, size);
+}
+
+extern "C" void* pvalloc(size_t bytes) {
+  return __libc_malloc_dispatch->pvalloc(bytes);
+}
+
+extern "C" void* realloc(void* oldMem, size_t bytes) {
+  return __libc_malloc_dispatch->realloc(oldMem, bytes);
+}
+
+extern "C" void* valloc(size_t bytes) {
+  return __libc_malloc_dispatch->valloc(bytes);
+}
+
+// We implement malloc debugging only in libc.so, so the code below
+// must be excluded if we compile this file for static libc.a
 #ifndef LIBC_STATIC
 #include <sys/system_properties.h>
 #include <dlfcn.h>
@@ -275,227 +280,222 @@
 
 template<typename FunctionType>
 static void 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 == NULL) {
-        error_log("%s: dlsym(\"%s\") failed", getprogname(), symbol);
-    }
+  char symbol[128];
+  snprintf(symbol, sizeof(symbol), "%s_%s", prefix, suffix);
+  *func = reinterpret_cast<FunctionType>(dlsym(malloc_impl_handler, symbol));
+  if (*func == NULL) {
+    error_log("%s: dlsym(\"%s\") failed", getprogname(), symbol);
+  }
 }
 
 static void InitMalloc(void* malloc_impl_handler, MallocDebug* table, const char* prefix) {
-    __libc_format_log(ANDROID_LOG_INFO, "libc", "%s: using libc.debug.malloc %d (%s)\n",
-                      getprogname(), g_malloc_debug_level, prefix);
+  __libc_format_log(ANDROID_LOG_INFO, "libc", "%s: using libc.debug.malloc %d (%s)\n",
+                    getprogname(), g_malloc_debug_level, prefix);
 
-    InitMallocFunction<MallocDebugMalloc>(malloc_impl_handler, &table->malloc, prefix, "malloc");
-    InitMallocFunction<MallocDebugFree>(malloc_impl_handler, &table->free, prefix, "free");
-    InitMallocFunction<MallocDebugCalloc>(malloc_impl_handler, &table->calloc, prefix, "calloc");
-    InitMallocFunction<MallocDebugRealloc>(malloc_impl_handler, &table->realloc, prefix, "realloc");
-    InitMallocFunction<MallocDebugMemalign>(malloc_impl_handler, &table->memalign, prefix, "memalign");
-    InitMallocFunction<MallocDebugMallocUsableSize>(malloc_impl_handler, &table->malloc_usable_size, prefix, "malloc_usable_size");
+  InitMallocFunction<MallocDebugCalloc>(malloc_impl_handler, &table->calloc, prefix, "calloc");
+  InitMallocFunction<MallocDebugFree>(malloc_impl_handler, &table->free, prefix, "free");
+  InitMallocFunction<MallocDebugMallinfo>(malloc_impl_handler, &table->mallinfo, prefix, "mallinfo");
+  InitMallocFunction<MallocDebugMalloc>(malloc_impl_handler, &table->malloc, prefix, "malloc");
+  InitMallocFunction<MallocDebugMallocUsableSize>(malloc_impl_handler, &table->malloc_usable_size, prefix, "malloc_usable_size");
+  InitMallocFunction<MallocDebugMemalign>(malloc_impl_handler, &table->memalign, prefix, "memalign");
+  InitMallocFunction<MallocDebugPosixMemalign>(malloc_impl_handler, &table->posix_memalign, prefix, "posix_memalign");
+  InitMallocFunction<MallocDebugPvalloc>(malloc_impl_handler, &table->pvalloc, prefix, "pvalloc");
+  InitMallocFunction<MallocDebugRealloc>(malloc_impl_handler, &table->realloc, prefix, "realloc");
+  InitMallocFunction<MallocDebugValloc>(malloc_impl_handler, &table->valloc, prefix, "valloc");
 }
 
-/* Initializes memory allocation framework once per process. */
+// Initializes memory allocation framework once per process.
 static void malloc_init_impl() {
-    const char* so_name = NULL;
-    MallocDebugInit malloc_debug_initialize = NULL;
-    unsigned int qemu_running = 0;
-    unsigned int memcheck_enabled = 0;
-    char env[PROP_VALUE_MAX];
-    char memcheck_tracing[PROP_VALUE_MAX];
-    char debug_program[PROP_VALUE_MAX];
+  const char* so_name = NULL;
+  MallocDebugInit malloc_debug_initialize = NULL;
+  unsigned int qemu_running = 0;
+  unsigned int memcheck_enabled = 0;
+  char env[PROP_VALUE_MAX];
+  char memcheck_tracing[PROP_VALUE_MAX];
+  char debug_program[PROP_VALUE_MAX];
 
-    /* Get custom malloc debug level. Note that emulator started with
-     * memory checking option will have priority over debug level set in
-     * libc.debug.malloc system property. */
-    if (__system_property_get("ro.kernel.qemu", env) && atoi(env)) {
-        qemu_running = 1;
-        if (__system_property_get("ro.kernel.memcheck", memcheck_tracing)) {
-            if (memcheck_tracing[0] != '0') {
-                // Emulator has started with memory tracing enabled. Enforce it.
-                g_malloc_debug_level = 20;
-                memcheck_enabled = 1;
-            }
-        }
+  // Get custom malloc debug level. Note that emulator started with
+  // memory checking option will have priority over debug level set in
+  // libc.debug.malloc system property.
+  if (__system_property_get("ro.kernel.qemu", env) && atoi(env)) {
+    qemu_running = 1;
+    if (__system_property_get("ro.kernel.memcheck", memcheck_tracing)) {
+      if (memcheck_tracing[0] != '0') {
+        // Emulator has started with memory tracing enabled. Enforce it.
+        g_malloc_debug_level = 20;
+        memcheck_enabled = 1;
+      }
     }
+  }
 
-    /* If debug level has not been set by memcheck option in the emulator,
-     * lets grab it from libc.debug.malloc system property. */
-    if (g_malloc_debug_level == 0 && __system_property_get("libc.debug.malloc", env)) {
-        g_malloc_debug_level = atoi(env);
+  // If debug level has not been set by memcheck option in the emulator,
+  // lets grab it from libc.debug.malloc system property.
+  if (g_malloc_debug_level == 0 && __system_property_get("libc.debug.malloc", env)) {
+    g_malloc_debug_level = atoi(env);
+  }
+
+  // Debug level 0 means that we should use default allocation routines.
+  if (g_malloc_debug_level == 0) {
+    return;
+  }
+
+  // If libc.debug.malloc.program is set and is not a substring of progname,
+  // then exit.
+  if (__system_property_get("libc.debug.malloc.program", debug_program)) {
+    if (!strstr(getprogname(), debug_program)) {
+      return;
     }
+  }
 
-    /* Debug level 0 means that we should use default allocation routines. */
-    if (g_malloc_debug_level == 0) {
-        return;
+  // mksh is way too leaky. http://b/7291287.
+  if (g_malloc_debug_level >= 10) {
+    if (strcmp(getprogname(), "sh") == 0 || strcmp(getprogname(), "/system/bin/sh") == 0) {
+      return;
     }
+  }
 
-    /* If libc.debug.malloc.program is set and is not a substring of progname,
-     * then exit.
-     */
-    if (__system_property_get("libc.debug.malloc.program", debug_program)) {
-        if (!strstr(getprogname(), debug_program)) {
-            return;
-        }
-    }
-
-    // mksh is way too leaky. http://b/7291287.
-    if (g_malloc_debug_level >= 10) {
-        if (strcmp(getprogname(), "sh") == 0 || strcmp(getprogname(), "/system/bin/sh") == 0) {
-            return;
-        }
-    }
-
-    // Choose the appropriate .so for the requested debug level.
-    switch (g_malloc_debug_level) {
-        case 1:
-        case 5:
-        case 10:
-            so_name = "libc_malloc_debug_leak.so";
-            break;
-        case 20:
-            // Quick check: debug level 20 can only be handled in emulator.
-            if (!qemu_running) {
-                error_log("%s: Debug level %d can only be set in emulator\n",
-                          getprogname(), g_malloc_debug_level);
-                return;
-            }
-            // Make sure that memory checking has been enabled in emulator.
-            if (!memcheck_enabled) {
-                error_log("%s: Memory checking is not enabled in the emulator\n",
-                          getprogname());
-                return;
-            }
-            so_name = "libc_malloc_debug_qemu.so";
-            break;
-        default:
-            error_log("%s: Debug level %d is unknown\n", getprogname(), g_malloc_debug_level);
-            return;
-    }
-
-    // Load .so that implements the required malloc debugging functionality.
-    void* malloc_impl_handle = dlopen(so_name, RTLD_LAZY);
-    if (malloc_impl_handle == NULL) {
-        error_log("%s: Missing module %s required for malloc debug level %d: %s",
-                  getprogname(), so_name, g_malloc_debug_level, dlerror());
-        return;
-    }
-
-    // Initialize malloc debugging in the loaded module.
-    malloc_debug_initialize = reinterpret_cast<MallocDebugInit>(dlsym(malloc_impl_handle,
-                                                                      "malloc_debug_initialize"));
-    if (malloc_debug_initialize == NULL) {
-        error_log("%s: Initialization routine is not found in %s\n",
-                  getprogname(), so_name);
-        dlclose(malloc_impl_handle);
-        return;
-    }
-    if (malloc_debug_initialize(&g_hash_table) == -1) {
-        dlclose(malloc_impl_handle);
-        return;
-    }
-
-    if (g_malloc_debug_level == 20) {
-        // For memory checker we need to do extra initialization.
-        typedef int (*MemCheckInit)(int, const char*);
-        MemCheckInit memcheck_initialize =
-            reinterpret_cast<MemCheckInit>(dlsym(malloc_impl_handle,
-                                                 "memcheck_initialize"));
-        if (memcheck_initialize == NULL) {
-            error_log("%s: memcheck_initialize routine is not found in %s\n",
-                      getprogname(), so_name);
-            dlclose(malloc_impl_handle);
-            return;
-        }
-
-        if (memcheck_initialize(MALLOC_ALIGNMENT, memcheck_tracing)) {
-            dlclose(malloc_impl_handle);
-            return;
-        }
-    }
-
-    // Initialize malloc dispatch table with appropriate routines.
-    static MallocDebug malloc_dispatch_table __attribute__((aligned(32))) = {
-        Malloc(malloc),
-        Malloc(free),
-        Malloc(calloc),
-        Malloc(realloc),
-        Malloc(memalign),
-        Malloc(malloc_usable_size)
-    };
-
-    switch (g_malloc_debug_level) {
-        case 1:
-            InitMalloc(malloc_impl_handle, &malloc_dispatch_table, "leak");
-            break;
-        case 5:
-            InitMalloc(malloc_impl_handle, &malloc_dispatch_table, "fill");
-            break;
-        case 10:
-            InitMalloc(malloc_impl_handle, &malloc_dispatch_table, "chk");
-            break;
-        case 20:
-            InitMalloc(malloc_impl_handle, &malloc_dispatch_table, "qemu_instrumented");
-            break;
-        default:
-            break;
-    }
-
-    // Make sure dispatch table is initialized
-    if ((malloc_dispatch_table.malloc == NULL) ||
-        (malloc_dispatch_table.free == NULL) ||
-        (malloc_dispatch_table.calloc == NULL) ||
-        (malloc_dispatch_table.realloc == NULL) ||
-        (malloc_dispatch_table.memalign == NULL) ||
-        (malloc_dispatch_table.malloc_usable_size == NULL)) {
-        error_log("%s: some symbols for libc.debug.malloc level %d were not found (see above)",
+  // Choose the appropriate .so for the requested debug level.
+  switch (g_malloc_debug_level) {
+    case 1:
+    case 5:
+    case 10:
+      so_name = "libc_malloc_debug_leak.so";
+      break;
+    case 20:
+      // Quick check: debug level 20 can only be handled in emulator.
+      if (!qemu_running) {
+        error_log("%s: Debug level %d can only be set in emulator\n",
                   getprogname(), g_malloc_debug_level);
-        dlclose(malloc_impl_handle);
-    } else {
-        __libc_malloc_dispatch = &malloc_dispatch_table;
-        libc_malloc_impl_handle = malloc_impl_handle;
+        return;
+      }
+      // Make sure that memory checking has been enabled in emulator.
+      if (!memcheck_enabled) {
+        error_log("%s: Memory checking is not enabled in the emulator\n", getprogname());
+        return;
+      }
+      so_name = "libc_malloc_debug_qemu.so";
+      break;
+    default:
+      error_log("%s: Debug level %d is unknown\n", getprogname(), g_malloc_debug_level);
+      return;
+  }
+
+  // Load .so that implements the required malloc debugging functionality.
+  void* malloc_impl_handle = dlopen(so_name, RTLD_LAZY);
+  if (malloc_impl_handle == NULL) {
+    error_log("%s: Missing module %s required for malloc debug level %d: %s",
+              getprogname(), so_name, g_malloc_debug_level, dlerror());
+    return;
+  }
+
+  // Initialize malloc debugging in the loaded module.
+  malloc_debug_initialize = reinterpret_cast<MallocDebugInit>(dlsym(malloc_impl_handle,
+                                                                    "malloc_debug_initialize"));
+  if (malloc_debug_initialize == NULL) {
+    error_log("%s: Initialization routine is not found in %s\n", getprogname(), so_name);
+    dlclose(malloc_impl_handle);
+    return;
+  }
+  if (malloc_debug_initialize(&g_hash_table) == -1) {
+    dlclose(malloc_impl_handle);
+    return;
+  }
+
+  if (g_malloc_debug_level == 20) {
+    // For memory checker we need to do extra initialization.
+    typedef int (*MemCheckInit)(int, const char*);
+    MemCheckInit memcheck_initialize =
+      reinterpret_cast<MemCheckInit>(dlsym(malloc_impl_handle, "memcheck_initialize"));
+    if (memcheck_initialize == NULL) {
+      error_log("%s: memcheck_initialize routine is not found in %s\n",
+                getprogname(), so_name);
+      dlclose(malloc_impl_handle);
+      return;
     }
+
+    if (memcheck_initialize(MALLOC_ALIGNMENT, memcheck_tracing)) {
+      dlclose(malloc_impl_handle);
+      return;
+    }
+  }
+
+  // No need to init the dispatch table because we can only get
+  // here if debug level is 1, 5, 10, or 20.
+  static MallocDebug malloc_dispatch_table __attribute__((aligned(32)));
+  switch (g_malloc_debug_level) {
+    case 1:
+      InitMalloc(malloc_impl_handle, &malloc_dispatch_table, "leak");
+      break;
+    case 5:
+      InitMalloc(malloc_impl_handle, &malloc_dispatch_table, "fill");
+      break;
+    case 10:
+      InitMalloc(malloc_impl_handle, &malloc_dispatch_table, "chk");
+      break;
+    case 20:
+      InitMalloc(malloc_impl_handle, &malloc_dispatch_table, "qemu_instrumented");
+      break;
+    default:
+      break;
+  }
+
+  // Make sure dispatch table is initialized
+  if ((malloc_dispatch_table.calloc == NULL) ||
+      (malloc_dispatch_table.free == NULL) ||
+      (malloc_dispatch_table.mallinfo == NULL) ||
+      (malloc_dispatch_table.malloc == NULL) ||
+      (malloc_dispatch_table.malloc_usable_size == NULL) ||
+      (malloc_dispatch_table.memalign == NULL) ||
+      (malloc_dispatch_table.posix_memalign == NULL) ||
+      (malloc_dispatch_table.pvalloc == NULL) ||
+      (malloc_dispatch_table.realloc == NULL) ||
+      (malloc_dispatch_table.valloc == NULL)) {
+    error_log("%s: some symbols for libc.debug.malloc level %d were not found (see above)",
+              getprogname(), g_malloc_debug_level);
+    dlclose(malloc_impl_handle);
+  } else {
+    __libc_malloc_dispatch = &malloc_dispatch_table;
+    libc_malloc_impl_handle = malloc_impl_handle;
+  }
 }
 
 static void malloc_fini_impl() {
-    // Our BSD stdio implementation doesn't close the standard streams, it only flushes them.
-    // And it doesn't do that until its atexit handler is run, and we run first!
-    // It's great that other unclosed FILE*s show up as malloc leaks, but we need to manually
-    // clean up the standard streams ourselves.
-    fclose(stdin);
-    fclose(stdout);
-    fclose(stderr);
+  // Our BSD stdio implementation doesn't close the standard streams, it only flushes them.
+  // And it doesn't do that until its atexit handler is run, and we run first!
+  // It's great that other unclosed FILE*s show up as malloc leaks, but we need to manually
+  // clean up the standard streams ourselves.
+  fclose(stdin);
+  fclose(stdout);
+  fclose(stderr);
 
-    if (libc_malloc_impl_handle != NULL) {
-        MallocDebugFini malloc_debug_finalize =
-            reinterpret_cast<MallocDebugFini>(dlsym(libc_malloc_impl_handle,
-                                                    "malloc_debug_finalize"));
-        if (malloc_debug_finalize != NULL) {
-            malloc_debug_finalize(g_malloc_debug_level);
-        }
+  if (libc_malloc_impl_handle != NULL) {
+    MallocDebugFini malloc_debug_finalize =
+      reinterpret_cast<MallocDebugFini>(dlsym(libc_malloc_impl_handle, "malloc_debug_finalize"));
+    if (malloc_debug_finalize != NULL) {
+      malloc_debug_finalize(g_malloc_debug_level);
     }
+  }
 }
 
 #endif  // !LIBC_STATIC
 
-/* Initializes memory allocation framework.
- * This routine is called from __libc_init routines implemented
- * in libc_init_static.c and libc_init_dynamic.c files.
- */
+// Initializes memory allocation framework.
+// This routine is called from __libc_init routines implemented
+// in libc_init_static.c and libc_init_dynamic.c files.
 extern "C" __LIBC_HIDDEN__ void malloc_debug_init() {
-#if defined(USE_DL_PREFIX) && !defined(LIBC_STATIC)
+#if !defined(LIBC_STATIC)
   static pthread_once_t malloc_init_once_ctl = PTHREAD_ONCE_INIT;
   if (pthread_once(&malloc_init_once_ctl, malloc_init_impl)) {
     error_log("Unable to initialize malloc_debug component.");
   }
-#endif  // USE_DL_PREFIX && !LIBC_STATIC
+#endif  // !LIBC_STATIC
 }
 
 extern "C" __LIBC_HIDDEN__ void malloc_debug_fini() {
-#if defined(USE_DL_PREFIX) && !defined(LIBC_STATIC)
+#if !defined(LIBC_STATIC)
   static pthread_once_t malloc_fini_once_ctl = PTHREAD_ONCE_INIT;
   if (pthread_once(&malloc_fini_once_ctl, malloc_fini_impl)) {
     error_log("Unable to finalize malloc_debug component.");
   }
-#endif  // USE_DL_PREFIX && !LIBC_STATIC
+#endif  // !LIBC_STATIC
 }