Adding upstream version 1:115.7.0.upstream/1%115.7.0upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1219 insertions, 0 deletions

diff --git a/xpcom/base/nsTraceRefcnt.cpp b/xpcom/base/nsTraceRefcnt.cpp
new file mode 100644
index 0000000000..1da0f6b647
--- /dev/null
+++ b/xpcom/base/nsTraceRefcnt.cpp
@@ -0,0 +1,1219 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsTraceRefcnt.h"
+
+#include "base/process_util.h"
+#include "mozilla/Attributes.h"
+#include "mozilla/AutoRestore.h"
+#include "mozilla/CycleCollectedJSContext.h"
+#include "mozilla/IntegerPrintfMacros.h"
+#include "mozilla/Path.h"
+#include "mozilla/Sprintf.h"
+#include "mozilla/StaticPtr.h"
+#include "nsXPCOMPrivate.h"
+#include "nscore.h"
+#include "nsClassHashtable.h"
+#include "nsContentUtils.h"
+#include "nsISupports.h"
+#include "nsHashKeys.h"
+#include "nsPrintfCString.h"
+#include "nsTArray.h"
+#include "nsTHashtable.h"
+#include "prenv.h"
+#include "prlink.h"
+#include "nsCRT.h"
+#include <math.h>
+#include "nsHashKeys.h"
+#include "mozilla/StackWalk.h"
+#include "nsThreadUtils.h"
+#include "CodeAddressService.h"
+
+#include "nsXULAppAPI.h"
+#ifdef XP_WIN
+#  include <io.h>
+#  include <process.h>
+#  define getpid _getpid
+#else
+#  include <unistd.h>
+#endif
+
+#include "mozilla/Atomics.h"
+#include "mozilla/AutoRestore.h"
+#include "mozilla/BlockingResourceBase.h"
+#include "mozilla/PoisonIOInterposer.h"
+#include "mozilla/UniquePtr.h"
+
+#include <string>
+#include <vector>
+
+#ifdef HAVE_DLOPEN
+#  include <dlfcn.h>
+#endif
+
+#ifdef MOZ_DMD
+#  include "nsMemoryInfoDumper.h"
+#endif
+
+// dynamic_cast<void*> is not supported on Windows without RTTI.
+#ifndef _WIN32
+#  define HAVE_CPP_DYNAMIC_CAST_TO_VOID_PTR
+#endif
+
+////////////////////////////////////////////////////////////////////////////////
+
+#include "prthread.h"
+
+class MOZ_CAPABILITY("mutex") TraceLogMutex
+    : private mozilla::detail::MutexImpl {
+ public:
+  explicit TraceLogMutex() : ::mozilla::detail::MutexImpl(){};
+
+ private:
+  friend class AutoTraceLogLock;
+
+  void Lock() MOZ_CAPABILITY_ACQUIRE() { ::mozilla::detail::MutexImpl::lock(); }
+  void Unlock() MOZ_CAPABILITY_RELEASE() {
+    ::mozilla::detail::MutexImpl::unlock();
+  }
+};
+
+static TraceLogMutex gTraceLog;
+
+class MOZ_RAII AutoTraceLogLock {
+ public:
+  explicit AutoTraceLogLock(TraceLogMutex& aMutex) : mMutex(aMutex) {
+    mMutex.Lock();
+  }
+
+  AutoTraceLogLock(const AutoTraceLogLock&) = delete;
+  AutoTraceLogLock& operator=(const AutoTraceLogLock&) = delete;
+  AutoTraceLogLock(AutoTraceLogLock&&) = delete;
+  AutoTraceLogLock& operator=(AutoTraceLogLock&&) = delete;
+
+  ~AutoTraceLogLock() { mMutex.Unlock(); }
+
+ private:
+  TraceLogMutex& mMutex;
+};
+
+class BloatEntry;
+struct SerialNumberRecord;
+
+using mozilla::AutoRestore;
+using mozilla::CodeAddressService;
+using mozilla::CycleCollectedJSContext;
+using mozilla::StaticAutoPtr;
+
+using BloatHash = nsClassHashtable<nsDepCharHashKey, BloatEntry>;
+using CharPtrSet = nsTHashtable<nsCharPtrHashKey>;
+using IntPtrSet = nsTHashtable<IntPtrHashKey>;
+using SerialHash = nsClassHashtable<nsVoidPtrHashKey, SerialNumberRecord>;
+
+static StaticAutoPtr<BloatHash> gBloatView;
+static StaticAutoPtr<CharPtrSet> gTypesToLog;
+static StaticAutoPtr<IntPtrSet> gObjectsToLog;
+static StaticAutoPtr<SerialHash> gSerialNumbers;
+
+static intptr_t gNextSerialNumber;
+static bool gDumpedStatistics = false;
+static bool gLogJSStacks = false;
+
+// By default, debug builds only do bloat logging. Bloat logging
+// only tries to record when an object is created or destroyed, so we
+// optimize the common case in NS_LogAddRef and NS_LogRelease where
+// only bloat logging is enabled and no logging needs to be done.
+enum LoggingType { NoLogging, OnlyBloatLogging, FullLogging };
+
+static LoggingType gLogging;
+
+static bool gLogLeaksOnly;
+
+#define BAD_TLS_INDEX ((unsigned)-1)
+
+// if gActivityTLS == BAD_TLS_INDEX, then we're
+// unitialized... otherwise this points to a NSPR TLS thread index
+// indicating whether addref activity is legal. If the PTR_TO_INT32 is 0 then
+// activity is ok, otherwise not!
+static unsigned gActivityTLS = BAD_TLS_INDEX;
+
+static bool gInitialized;
+static nsrefcnt gInitCount;
+
+static FILE* gBloatLog = nullptr;
+static FILE* gRefcntsLog = nullptr;
+static FILE* gAllocLog = nullptr;
+static FILE* gCOMPtrLog = nullptr;
+
+static void WalkTheStackSavingLocations(std::vector<void*>& aLocations,
+                                        const void* aFirstFramePC);
+
+struct SerialNumberRecord {
+  SerialNumberRecord()
+      : serialNumber(++gNextSerialNumber), refCount(0), COMPtrCount(0) {}
+
+  intptr_t serialNumber;
+  int32_t refCount;
+  int32_t COMPtrCount;
+  // We use std:: classes here rather than the XPCOM equivalents because the
+  // XPCOM equivalents do leak-checking, and if you try to leak-check while
+  // leak-checking, you're gonna have a bad time.
+  std::vector<void*> allocationStack;
+  mozilla::UniquePtr<char[]> jsStack;
+
+  void SaveJSStack() {
+    // If this thread isn't running JS, there's nothing to do.
+    if (!CycleCollectedJSContext::Get()) {
+      return;
+    }
+
+    if (!nsContentUtils::IsInitialized()) {
+      return;
+    }
+
+    JSContext* cx = nsContentUtils::GetCurrentJSContext();
+    if (!cx) {
+      return;
+    }
+
+    JS::UniqueChars chars = xpc_PrintJSStack(cx,
+                                             /*showArgs=*/false,
+                                             /*showLocals=*/false,
+                                             /*showThisProps=*/false);
+    size_t len = strlen(chars.get());
+    jsStack = mozilla::MakeUnique<char[]>(len + 1);
+    memcpy(jsStack.get(), chars.get(), len + 1);
+  }
+};
+
+struct nsTraceRefcntStats {
+  uint64_t mCreates;
+  uint64_t mDestroys;
+
+  bool HaveLeaks() const { return mCreates != mDestroys; }
+
+  void Clear() {
+    mCreates = 0;
+    mDestroys = 0;
+  }
+
+  int64_t NumLeaked() const { return (int64_t)(mCreates - mDestroys); }
+};
+
+#ifdef DEBUG
+static void AssertActivityIsLegal(const char* aType, const char* aAction) {
+  if (gActivityTLS == BAD_TLS_INDEX || PR_GetThreadPrivate(gActivityTLS)) {
+    char buf[1024];
+    SprintfLiteral(buf, "XPCOM object %s %s from static ctor/dtor", aType,
+                   aAction);
+
+    if (PR_GetEnv("MOZ_FATAL_STATIC_XPCOM_CTORS_DTORS")) {
+      MOZ_CRASH_UNSAFE_PRINTF("%s", buf);
+    } else {
+      NS_WARNING(buf);
+    }
+  }
+}
+#  define ASSERT_ACTIVITY_IS_LEGAL(type_, action_) \
+    do {                                           \
+      AssertActivityIsLegal(type_, action_);       \
+    } while (0)
+#else
+#  define ASSERT_ACTIVITY_IS_LEGAL(type_, action_) \
+    do {                                           \
+    } while (0)
+#endif  // DEBUG
+
+////////////////////////////////////////////////////////////////////////////////
+
+mozilla::StaticAutoPtr<CodeAddressService<>> gCodeAddressService;
+
+////////////////////////////////////////////////////////////////////////////////
+
+class BloatEntry {
+ public:
+  BloatEntry(const char* aClassName, uint32_t aClassSize)
+      : mClassSize(aClassSize), mStats() {
+    MOZ_ASSERT(strlen(aClassName) > 0, "BloatEntry name must be non-empty");
+    mClassName = aClassName;
+    mStats.Clear();
+    mTotalLeaked = 0;
+  }
+
+  ~BloatEntry() = default;
+
+  uint32_t GetClassSize() { return (uint32_t)mClassSize; }
+  const char* GetClassName() { return mClassName; }
+
+  void Ctor() { mStats.mCreates++; }
+
+  void Dtor() { mStats.mDestroys++; }
+
+  void Total(BloatEntry* aTotal) {
+    aTotal->mStats.mCreates += mStats.mCreates;
+    aTotal->mStats.mDestroys += mStats.mDestroys;
+    aTotal->mClassSize +=
+        mClassSize * mStats.mCreates;  // adjust for average in DumpTotal
+    aTotal->mTotalLeaked += mClassSize * mStats.NumLeaked();
+  }
+
+  void DumpTotal(FILE* aOut) {
+    mClassSize /= mStats.mCreates;
+    Dump(-1, aOut);
+  }
+
+  bool PrintDumpHeader(FILE* aOut, const char* aMsg) {
+    fprintf(aOut, "\n== BloatView: %s, %s process %d\n", aMsg,
+            XRE_GetProcessTypeString(), getpid());
+    if (gLogLeaksOnly && !mStats.HaveLeaks()) {
+      return false;
+    }
+
+    // clang-format off
+    fprintf(aOut,
+            "\n" \
+            "     |<----------------Class--------------->|<-----Bytes------>|<----Objects---->|\n" \
+            "     |                                      | Per-Inst   Leaked|   Total      Rem|\n");
+    // clang-format on
+
+    this->DumpTotal(aOut);
+
+    return true;
+  }
+
+  void Dump(int aIndex, FILE* aOut) {
+    if (gLogLeaksOnly && !mStats.HaveLeaks()) {
+      return;
+    }
+
+    if (mStats.HaveLeaks() || mStats.mCreates != 0) {
+      fprintf(aOut,
+              "%4d |%-38.38s| %8d %8" PRId64 "|%8" PRIu64 " %8" PRId64 "|\n",
+              aIndex + 1, mClassName, GetClassSize(),
+              nsCRT::strcmp(mClassName, "TOTAL")
+                  ? (mStats.NumLeaked() * GetClassSize())
+                  : mTotalLeaked,
+              mStats.mCreates, mStats.NumLeaked());
+    }
+  }
+
+ protected:
+  const char* mClassName;
+  // mClassSize is stored as a double because of the way we compute the avg
+  // class size for total bloat.
+  double mClassSize;
+  // mTotalLeaked is only used for the TOTAL entry.
+  int64_t mTotalLeaked;
+  nsTraceRefcntStats mStats;
+};
+
+static void EnsureBloatView() {
+  if (!gBloatView) {
+    gBloatView = new BloatHash(256);
+  }
+}
+
+static BloatEntry* GetBloatEntry(const char* aTypeName,
+                                 uint32_t aInstanceSize) {
+  EnsureBloatView();
+  BloatEntry* entry = gBloatView->Get(aTypeName);
+  if (!entry && aInstanceSize > 0) {
+    entry = gBloatView
+                ->InsertOrUpdate(aTypeName, mozilla::MakeUnique<BloatEntry>(
+                                                aTypeName, aInstanceSize))
+                .get();
+  } else {
+    MOZ_ASSERT(
+        aInstanceSize == 0 || entry->GetClassSize() == aInstanceSize,
+        "Mismatched sizes were recorded in the memory leak logging table. "
+        "The usual cause of this is having a templated class that uses "
+        "MOZ_COUNT_{C,D}TOR in the constructor or destructor, respectively. "
+        "As a workaround, the MOZ_COUNT_{C,D}TOR calls can be moved to a "
+        "non-templated base class. Another possible cause is a runnable with "
+        "an mName that matches another refcounted class, or two refcounted "
+        "classes with the same class name in different C++ namespaces.");
+  }
+  return entry;
+}
+
+static void DumpSerialNumbers(const SerialHash::ConstIterator& aHashEntry,
+                              FILE* aFd, bool aDumpAsStringBuffer) {
+  SerialNumberRecord* record = aHashEntry.UserData();
+  auto* outputFile = aFd;
+#ifdef HAVE_CPP_DYNAMIC_CAST_TO_VOID_PTR
+  fprintf(outputFile, "%" PRIdPTR " @%p (%d references; %d from COMPtrs)\n",
+          record->serialNumber, aHashEntry.Key(), record->refCount,
+          record->COMPtrCount);
+#else
+  fprintf(outputFile, "%" PRIdPTR " @%p (%d references)\n",
+          record->serialNumber, aHashEntry.Key(), record->refCount);
+#endif
+
+  if (aDumpAsStringBuffer) {
+    // This output will be wrong if the nsStringBuffer was used to
+    // store a char16_t string.
+    auto* buffer = static_cast<const nsStringBuffer*>(aHashEntry.Key());
+    nsDependentCString bufferString(static_cast<char*>(buffer->Data()));
+    fprintf(outputFile,
+            "Contents of leaked nsStringBuffer with storage size %d as a "
+            "char*: %s\n",
+            buffer->StorageSize(), bufferString.get());
+  }
+
+  if (!record->allocationStack.empty()) {
+    static const size_t bufLen = 1024;
+    char buf[bufLen];
+    fprintf(outputFile, "allocation stack:\n");
+    for (size_t i = 0, length = record->allocationStack.size(); i < length;
+         ++i) {
+      gCodeAddressService->GetLocation(i, record->allocationStack[i], buf,
+                                       bufLen);
+      fprintf(outputFile, "%s\n", buf);
+    }
+  }
+
+  if (gLogJSStacks) {
+    if (record->jsStack) {
+      fprintf(outputFile, "JS allocation stack:\n%s\n", record->jsStack.get());
+    } else {
+      fprintf(outputFile, "There is no JS context on the stack.\n");
+    }
+  }
+}
+
+template <>
+class nsDefaultComparator<BloatEntry*, BloatEntry*> {
+ public:
+  bool Equals(BloatEntry* const& aEntry1, BloatEntry* const& aEntry2) const {
+    return strcmp(aEntry1->GetClassName(), aEntry2->GetClassName()) == 0;
+  }
+  bool LessThan(BloatEntry* const& aEntry1, BloatEntry* const& aEntry2) const {
+    return strcmp(aEntry1->GetClassName(), aEntry2->GetClassName()) < 0;
+  }
+};
+
+nsresult nsTraceRefcnt::DumpStatistics() {
+  if (!gBloatLog || !gBloatView) {
+    return NS_ERROR_FAILURE;
+  }
+
+  AutoTraceLogLock lock(gTraceLog);
+
+  MOZ_ASSERT(!gDumpedStatistics,
+             "Calling DumpStatistics more than once may result in "
+             "bogus positive or negative leaks being reported");
+  gDumpedStatistics = true;
+
+  // Don't try to log while we hold the lock, we'd deadlock.
+  AutoRestore<LoggingType> saveLogging(gLogging);
+  gLogging = NoLogging;
+
+  BloatEntry total("TOTAL", 0);
+  for (const auto& data : gBloatView->Values()) {
+    if (nsCRT::strcmp(data->GetClassName(), "TOTAL") != 0) {
+      data->Total(&total);
+    }
+  }
+
+  const char* msg;
+  if (gLogLeaksOnly) {
+    msg = "ALL (cumulative) LEAK STATISTICS";
+  } else {
+    msg = "ALL (cumulative) LEAK AND BLOAT STATISTICS";
+  }
+  const bool leaked = total.PrintDumpHeader(gBloatLog, msg);
+
+  nsTArray<BloatEntry*> entries(gBloatView->Count());
+  for (const auto& data : gBloatView->Values()) {
+    entries.AppendElement(data.get());
+  }
+
+  const uint32_t count = entries.Length();
+
+  if (!gLogLeaksOnly || leaked) {
+    // Sort the entries alphabetically by classname.
+    entries.Sort();
+
+    for (uint32_t i = 0; i < count; ++i) {
+      BloatEntry* entry = entries[i];
+      entry->Dump(i, gBloatLog);
+    }
+
+    fprintf(gBloatLog, "\n");
+  }
+
+  fprintf(gBloatLog, "nsTraceRefcnt::DumpStatistics: %d entries\n", count);
+
+  if (gSerialNumbers) {
+    bool onlyLoggingStringBuffers = gTypesToLog && gTypesToLog->Count() == 1 &&
+                                    gTypesToLog->Contains("nsStringBuffer");
+
+    fprintf(gBloatLog, "\nSerial Numbers of Leaked Objects:\n");
+    for (auto iter = gSerialNumbers->ConstIter(); !iter.Done(); iter.Next()) {
+      DumpSerialNumbers(iter, gBloatLog, onlyLoggingStringBuffers);
+    }
+  }
+
+  return NS_OK;
+}
+
+void nsTraceRefcnt::ResetStatistics() {
+  AutoTraceLogLock lock(gTraceLog);
+  gBloatView = nullptr;
+}
+
+static intptr_t GetSerialNumber(void* aPtr, bool aCreate, void* aFirstFramePC) {
+  if (!aCreate) {
+    auto record = gSerialNumbers->Get(aPtr);
+    return record ? record->serialNumber : 0;
+  }
+
+  gSerialNumbers->WithEntryHandle(aPtr, [aFirstFramePC](auto&& entry) {
+    if (entry) {
+      MOZ_CRASH(
+          "If an object already has a serial number, we should be destroying "
+          "it.");
+    }
+
+    auto& record = entry.Insert(mozilla::MakeUnique<SerialNumberRecord>());
+    WalkTheStackSavingLocations(record->allocationStack, aFirstFramePC);
+    if (gLogJSStacks) {
+      record->SaveJSStack();
+    }
+  });
+  return gNextSerialNumber;
+}
+
+static void RecycleSerialNumberPtr(void* aPtr) { gSerialNumbers->Remove(aPtr); }
+
+static bool LogThisObj(intptr_t aSerialNumber) {
+  return gObjectsToLog->Contains(aSerialNumber);
+}
+
+using EnvCharType = mozilla::filesystem::Path::value_type;
+
+static bool InitLog(const EnvCharType* aEnvVar, const char* aMsg,
+                    FILE** aResult, const char* aProcType) {
+#ifdef XP_WIN
+  // This is gross, I know.
+  const wchar_t* envvar = reinterpret_cast<const wchar_t*>(aEnvVar);
+  const char16_t* value = reinterpret_cast<const char16_t*>(::_wgetenv(envvar));
+#  define ENVVAR_PRINTF "%S"
+#else
+  const char* envvar = aEnvVar;
+  const char* value = ::getenv(aEnvVar);
+#  define ENVVAR_PRINTF "%s"
+#endif
+
+  if (value) {
+    nsTDependentString<EnvCharType> fname(value);
+    if (fname.EqualsLiteral("1")) {
+      *aResult = stdout;
+      fprintf(stdout, "### " ENVVAR_PRINTF " defined -- logging %s to stdout\n",
+              envvar, aMsg);
+      return true;
+    }
+    if (fname.EqualsLiteral("2")) {
+      *aResult = stderr;
+      fprintf(stdout, "### " ENVVAR_PRINTF " defined -- logging %s to stderr\n",
+              envvar, aMsg);
+      return true;
+    }
+    if (!XRE_IsParentProcess()) {
+      nsTString<EnvCharType> extension;
+      extension.AssignLiteral(".log");
+      bool hasLogExtension = StringEndsWith(fname, extension);
+      if (hasLogExtension) {
+        fname.Cut(fname.Length() - 4, 4);
+      }
+      fname.Append('_');
+      fname.AppendASCII(aProcType);
+      fname.AppendLiteral("_pid");
+      fname.AppendInt((uint32_t)getpid());
+      if (hasLogExtension) {
+        fname.AppendLiteral(".log");
+      }
+    }
+#ifdef XP_WIN
+    FILE* stream = ::_wfopen(fname.get(), L"wN");
+    const wchar_t* fp = (const wchar_t*)fname.get();
+#else
+    FILE* stream = ::fopen(fname.get(), "w");
+    const char* fp = fname.get();
+#endif
+    if (stream) {
+      MozillaRegisterDebugFD(fileno(stream));
+#ifdef MOZ_ENABLE_FORKSERVER
+      base::RegisterForkServerNoCloseFD(fileno(stream));
+#endif
+      *aResult = stream;
+      fprintf(stderr,
+              "### " ENVVAR_PRINTF " defined -- logging %s to " ENVVAR_PRINTF
+              "\n",
+              envvar, aMsg, fp);
+
+      return true;
+    }
+
+    fprintf(stderr,
+            "### " ENVVAR_PRINTF
+            " defined -- unable to log %s to " ENVVAR_PRINTF "\n",
+            envvar, aMsg, fp);
+    MOZ_ASSERT(false, "Tried and failed to create an XPCOM log");
+
+#undef ENVVAR_PRINTF
+  }
+  return false;
+}
+
+static void maybeUnregisterAndCloseFile(FILE*& aFile) {
+  if (!aFile) {
+    return;
+  }
+
+  MozillaUnRegisterDebugFILE(aFile);
+  fclose(aFile);
+  aFile = nullptr;
+}
+
+static void DoInitTraceLog(const char* aProcType) {
+#ifdef XP_WIN
+#  define ENVVAR(x) u"" x
+#else
+#  define ENVVAR(x) x
+#endif
+
+  bool defined = InitLog(ENVVAR("XPCOM_MEM_BLOAT_LOG"), "bloat/leaks",
+                         &gBloatLog, aProcType);
+  if (!defined) {
+    gLogLeaksOnly =
+        InitLog(ENVVAR("XPCOM_MEM_LEAK_LOG"), "leaks", &gBloatLog, aProcType);
+  }
+  if (defined || gLogLeaksOnly) {
+    // Use the same bloat view, if there is one, to keep it consistent
+    // between the fork server and content processes.
+    EnsureBloatView();
+  } else if (gBloatView) {
+    nsTraceRefcnt::ResetStatistics();
+  }
+
+  InitLog(ENVVAR("XPCOM_MEM_REFCNT_LOG"), "refcounts", &gRefcntsLog, aProcType);
+
+  InitLog(ENVVAR("XPCOM_MEM_ALLOC_LOG"), "new/delete", &gAllocLog, aProcType);
+
+  const char* classes = getenv("XPCOM_MEM_LOG_CLASSES");
+
+#ifdef HAVE_CPP_DYNAMIC_CAST_TO_VOID_PTR
+  if (classes) {
+    InitLog(ENVVAR("XPCOM_MEM_COMPTR_LOG"), "nsCOMPtr", &gCOMPtrLog, aProcType);
+  } else {
+    if (getenv("XPCOM_MEM_COMPTR_LOG")) {
+      fprintf(stdout,
+              "### XPCOM_MEM_COMPTR_LOG defined -- "
+              "but XPCOM_MEM_LOG_CLASSES is not defined\n");
+    }
+  }
+#else
+  const char* comptr_log = getenv("XPCOM_MEM_COMPTR_LOG");
+  if (comptr_log) {
+    fprintf(stdout,
+            "### XPCOM_MEM_COMPTR_LOG defined -- "
+            "but it will not work without dynamic_cast\n");
+  }
+#endif  // HAVE_CPP_DYNAMIC_CAST_TO_VOID_PTR
+
+#undef ENVVAR
+
+  if (classes) {
+    // if XPCOM_MEM_LOG_CLASSES was set to some value, the value is interpreted
+    // as a list of class names to track
+    //
+    // Use the same |gTypesToLog| and |gSerialNumbers| to keep them
+    // consistent through the fork server and content processes.
+    // Without this, counters will be incorrect.
+    if (!gTypesToLog) {
+      gTypesToLog = new CharPtrSet(256);
+    }
+
+    fprintf(stdout,
+            "### XPCOM_MEM_LOG_CLASSES defined -- "
+            "only logging these classes: ");
+    const char* cp = classes;
+    for (;;) {
+      char* cm = (char*)strchr(cp, ',');
+      if (cm) {
+        *cm = '\0';
+      }
+      if (!gTypesToLog->Contains(cp)) {
+        gTypesToLog->PutEntry(cp);
+      }
+      fprintf(stdout, "%s ", cp);
+      if (!cm) {
+        break;
+      }
+      *cm = ',';
+      cp = cm + 1;
+    }
+    fprintf(stdout, "\n");
+
+    if (!gSerialNumbers) {
+      gSerialNumbers = new SerialHash(256);
+    }
+  } else {
+    gTypesToLog = nullptr;
+    gSerialNumbers = nullptr;
+  }
+
+  const char* objects = getenv("XPCOM_MEM_LOG_OBJECTS");
+  if (objects) {
+    gObjectsToLog = new IntPtrSet(256);
+
+    if (!(gRefcntsLog || gAllocLog || gCOMPtrLog)) {
+      fprintf(stdout,
+              "### XPCOM_MEM_LOG_OBJECTS defined -- "
+              "but none of XPCOM_MEM_(REFCNT|ALLOC|COMPTR)_LOG is defined\n");
+    } else {
+      fprintf(stdout,
+              "### XPCOM_MEM_LOG_OBJECTS defined -- "
+              "only logging these objects: ");
+      const char* cp = objects;
+      for (;;) {
+        char* cm = (char*)strchr(cp, ',');
+        if (cm) {
+          *cm = '\0';
+        }
+        intptr_t top = 0;
+        intptr_t bottom = 0;
+        while (*cp) {
+          if (*cp == '-') {
+            bottom = top;
+            top = 0;
+            ++cp;
+          }
+          top *= 10;
+          top += *cp - '0';
+          ++cp;
+        }
+        if (!bottom) {
+          bottom = top;
+        }
+        for (intptr_t serialno = bottom; serialno <= top; serialno++) {
+          gObjectsToLog->PutEntry(serialno);
+          fprintf(stdout, "%" PRIdPTR " ", serialno);
+        }
+        if (!cm) {
+          break;
+        }
+        *cm = ',';
+        cp = cm + 1;
+      }
+      fprintf(stdout, "\n");
+    }
+  }
+
+  if (getenv("XPCOM_MEM_LOG_JS_STACK")) {
+    fprintf(stdout, "### XPCOM_MEM_LOG_JS_STACK defined\n");
+    gLogJSStacks = true;
+  }
+
+  if (gBloatLog) {
+    gLogging = OnlyBloatLogging;
+  }
+
+  if (gRefcntsLog || gAllocLog || gCOMPtrLog) {
+    gLogging = FullLogging;
+  }
+}
+
+static void InitTraceLog() {
+  if (gInitialized) {
+    return;
+  }
+  gInitialized = true;
+
+  DoInitTraceLog(XRE_GetProcessTypeString());
+}
+
+extern "C" {
+
+static void EnsureWrite(FILE* aStream, const char* aBuf, size_t aLen) {
+#ifdef XP_WIN
+  int fd = _fileno(aStream);
+#else
+  int fd = fileno(aStream);
+#endif
+  while (aLen > 0) {
+#ifdef XP_WIN
+    auto written = _write(fd, aBuf, aLen);
+#else
+    auto written = write(fd, aBuf, aLen);
+#endif
+    if (written <= 0 || size_t(written) > aLen) {
+      break;
+    }
+    aBuf += written;
+    aLen -= written;
+  }
+}
+
+static void PrintStackFrameCached(uint32_t aFrameNumber, void* aPC, void* aSP,
+                                  void* aClosure) {
+  auto stream = static_cast<FILE*>(aClosure);
+  static const int buflen = 1024;
+  char buf[buflen + 5] = "    ";  // 5 for leading "    " and trailing '\n'
+  int len =
+      gCodeAddressService->GetLocation(aFrameNumber, aPC, buf + 4, buflen);
+  len = std::min(len, buflen + 1 - 2) + 4;
+  buf[len++] = '\n';
+  buf[len] = '\0';
+  fflush(stream);
+  EnsureWrite(stream, buf, len);
+}
+
+static void RecordStackFrame(uint32_t /*aFrameNumber*/, void* aPC,
+                             void* /*aSP*/, void* aClosure) {
+  auto locations = static_cast<std::vector<void*>*>(aClosure);
+  locations->push_back(aPC);
+}
+}
+
+/**
+ * This is a variant of |MozWalkTheStack| that uses |CodeAddressService| to
+ * cache the results of |NS_DescribeCodeAddress|. If |WalkTheStackCached| is
+ * being called frequently, it will be a few orders of magnitude faster than
+ * |MozWalkTheStack|. However, the cache uses a lot of memory, which can cause
+ * OOM crashes. Therefore, this should only be used for things like refcount
+ * logging which walk the stack extremely frequently.
+ */
+static void WalkTheStackCached(FILE* aStream, const void* aFirstFramePC) {
+  if (!gCodeAddressService) {
+    gCodeAddressService = new CodeAddressService<>();
+  }
+  MozStackWalk(PrintStackFrameCached, aFirstFramePC, /* maxFrames */ 0,
+               aStream);
+}
+
+static void WalkTheStackSavingLocations(std::vector<void*>& aLocations,
+                                        const void* aFirstFramePC) {
+  if (!gCodeAddressService) {
+    gCodeAddressService = new CodeAddressService<>();
+  }
+  MozStackWalk(RecordStackFrame, aFirstFramePC, /* maxFrames */ 0, &aLocations);
+}
+
+//----------------------------------------------------------------------
+
+EXPORT_XPCOM_API(void)
+NS_LogInit() {
+  NS_SetMainThread();
+
+  // FIXME: This is called multiple times, we should probably not allow that.
+  if (++gInitCount) {
+    nsTraceRefcnt::SetActivityIsLegal(true);
+  }
+}
+
+EXPORT_XPCOM_API(void)
+NS_LogTerm() { mozilla::LogTerm(); }
+
+#ifdef MOZ_DMD
+// If MOZ_DMD_SHUTDOWN_LOG is set, dump a DMD report to a file.
+// The value of this environment variable is used as the prefix
+// of the file name, so you probably want something like "/tmp/".
+// By default, this is run in all processes, but you can record a
+// log only for a specific process type by setting MOZ_DMD_LOG_PROCESS
+// to the process type you want to log, such as "default" or "tab".
+// This method can't use the higher level XPCOM file utilities
+// because it is run very late in shutdown to avoid recording
+// information about refcount logging entries.
+static void LogDMDFile() {
+  const char* dmdFilePrefix = PR_GetEnv("MOZ_DMD_SHUTDOWN_LOG");
+  if (!dmdFilePrefix) {
+    return;
+  }
+
+  const char* logProcessEnv = PR_GetEnv("MOZ_DMD_LOG_PROCESS");
+  if (logProcessEnv && !!strcmp(logProcessEnv, XRE_GetProcessTypeString())) {
+    return;
+  }
+
+  nsPrintfCString fileName("%sdmd-%" PRIPID ".log.gz", dmdFilePrefix,
+                           base::GetCurrentProcId());
+  FILE* logFile = fopen(fileName.get(), "w");
+  if (NS_WARN_IF(!logFile)) {
+    return;
+  }
+
+  nsMemoryInfoDumper::DumpDMDToFile(logFile);
+}
+#endif  // MOZ_DMD
+
+namespace mozilla {
+void LogTerm() {
+  NS_ASSERTION(gInitCount > 0, "NS_LogTerm without matching NS_LogInit");
+
+  if (--gInitCount == 0) {
+#ifdef DEBUG
+    /* FIXME bug 491977: This is only going to operate on the
+     * BlockingResourceBase which is compiled into
+     * libxul/libxpcom_core.so. Anyone using external linkage will
+     * have their own copy of BlockingResourceBase statics which will
+     * not be freed by this method.
+     *
+     * It sounds like what we really want is to be able to register a
+     * callback function to call at XPCOM shutdown.  Note that with
+     * this solution, however, we need to guarantee that
+     * BlockingResourceBase::Shutdown() runs after all other shutdown
+     * functions.
+     */
+    BlockingResourceBase::Shutdown();
+#endif
+
+    if (gInitialized) {
+      nsTraceRefcnt::DumpStatistics();
+      nsTraceRefcnt::ResetStatistics();
+    }
+    nsTraceRefcnt::Shutdown();
+    nsTraceRefcnt::SetActivityIsLegal(false);
+    gActivityTLS = BAD_TLS_INDEX;
+
+#ifdef MOZ_DMD
+    LogDMDFile();
+#endif
+  }
+}
+
+}  // namespace mozilla
+
+EXPORT_XPCOM_API(MOZ_NEVER_INLINE void)
+NS_LogAddRef(void* aPtr, nsrefcnt aRefcnt, const char* aClass,
+             uint32_t aClassSize) {
+  ASSERT_ACTIVITY_IS_LEGAL(aClass, "addrefed");
+  if (!gInitialized) {
+    InitTraceLog();
+  }
+  if (gLogging == NoLogging) {
+    return;
+  }
+  if (aRefcnt == 1 || gLogging == FullLogging) {
+    AutoTraceLogLock lock(gTraceLog);
+
+    if (aRefcnt == 1 && gBloatLog) {
+      BloatEntry* entry = GetBloatEntry(aClass, aClassSize);
+      if (entry) {
+        entry->Ctor();
+      }
+    }
+
+    // Here's the case where MOZ_COUNT_CTOR was not used,
+    // yet we still want to see creation information:
+
+    bool loggingThisType = (!gTypesToLog || gTypesToLog->Contains(aClass));
+    intptr_t serialno = 0;
+    if (gSerialNumbers && loggingThisType) {
+      serialno = GetSerialNumber(aPtr, aRefcnt == 1, CallerPC());
+      MOZ_ASSERT(serialno != 0,
+                 "Serial number requested for unrecognized pointer!  "
+                 "Are you memmoving a refcounted object?");
+      auto record = gSerialNumbers->Get(aPtr);
+      if (record) {
+        ++record->refCount;
+      }
+    }
+
+    bool loggingThisObject = (!gObjectsToLog || LogThisObj(serialno));
+    if (aRefcnt == 1 && gAllocLog && loggingThisType && loggingThisObject) {
+      fprintf(gAllocLog, "\n<%s> %p %" PRIdPTR " Create [thread %p]\n", aClass,
+              aPtr, serialno, PR_GetCurrentThread());
+      WalkTheStackCached(gAllocLog, CallerPC());
+    }
+
+    if (gRefcntsLog && loggingThisType && loggingThisObject) {
+      // Can't use MOZ_LOG(), b/c it truncates the line
+      fprintf(gRefcntsLog,
+              "\n<%s> %p %" PRIuPTR " AddRef %" PRIuPTR " [thread %p]\n",
+              aClass, aPtr, serialno, aRefcnt, PR_GetCurrentThread());
+      WalkTheStackCached(gRefcntsLog, CallerPC());
+      fflush(gRefcntsLog);
+    }
+  }
+}
+
+EXPORT_XPCOM_API(MOZ_NEVER_INLINE void)
+NS_LogRelease(void* aPtr, nsrefcnt aRefcnt, const char* aClass) {
+  ASSERT_ACTIVITY_IS_LEGAL(aClass, "released");
+  if (!gInitialized) {
+    InitTraceLog();
+  }
+  if (gLogging == NoLogging) {
+    return;
+  }
+  if (aRefcnt == 0 || gLogging == FullLogging) {
+    AutoTraceLogLock lock(gTraceLog);
+
+    if (aRefcnt == 0 && gBloatLog) {
+      BloatEntry* entry = GetBloatEntry(aClass, 0);
+      if (entry) {
+        entry->Dtor();
+      }
+    }
+
+    bool loggingThisType = (!gTypesToLog || gTypesToLog->Contains(aClass));
+    intptr_t serialno = 0;
+    if (gSerialNumbers && loggingThisType) {
+      serialno = GetSerialNumber(aPtr, false, CallerPC());
+      MOZ_ASSERT(serialno != 0,
+                 "Serial number requested for unrecognized pointer!  "
+                 "Are you memmoving a refcounted object?");
+      auto record = gSerialNumbers->Get(aPtr);
+      if (record) {
+        --record->refCount;
+      }
+    }
+
+    bool loggingThisObject = (!gObjectsToLog || LogThisObj(serialno));
+    if (gRefcntsLog && loggingThisType && loggingThisObject) {
+      // Can't use MOZ_LOG(), b/c it truncates the line
+      fprintf(gRefcntsLog,
+              "\n<%s> %p %" PRIuPTR " Release %" PRIuPTR " [thread %p]\n",
+              aClass, aPtr, serialno, aRefcnt, PR_GetCurrentThread());
+      WalkTheStackCached(gRefcntsLog, CallerPC());
+      fflush(gRefcntsLog);
+    }
+
+    // Here's the case where MOZ_COUNT_DTOR was not used,
+    // yet we still want to see deletion information:
+
+    if (aRefcnt == 0 && gAllocLog && loggingThisType && loggingThisObject) {
+      fprintf(gAllocLog, "\n<%s> %p %" PRIdPTR " Destroy [thread %p]\n", aClass,
+              aPtr, serialno, PR_GetCurrentThread());
+      WalkTheStackCached(gAllocLog, CallerPC());
+    }
+
+    if (aRefcnt == 0 && gSerialNumbers && loggingThisType) {
+      RecycleSerialNumberPtr(aPtr);
+    }
+  }
+}
+
+EXPORT_XPCOM_API(MOZ_NEVER_INLINE void)
+NS_LogCtor(void* aPtr, const char* aType, uint32_t aInstanceSize) {
+  ASSERT_ACTIVITY_IS_LEGAL(aType, "constructed");
+  if (!gInitialized) {
+    InitTraceLog();
+  }
+
+  if (gLogging == NoLogging) {
+    return;
+  }
+
+  AutoTraceLogLock lock(gTraceLog);
+
+  if (gBloatLog) {
+    BloatEntry* entry = GetBloatEntry(aType, aInstanceSize);
+    if (entry) {
+      entry->Ctor();
+    }
+  }
+
+  bool loggingThisType = (!gTypesToLog || gTypesToLog->Contains(aType));
+  intptr_t serialno = 0;
+  if (gSerialNumbers && loggingThisType) {
+    serialno = GetSerialNumber(aPtr, true, CallerPC());
+    MOZ_ASSERT(serialno != 0,
+               "GetSerialNumber should never return 0 when passed true");
+  }
+
+  bool loggingThisObject = (!gObjectsToLog || LogThisObj(serialno));
+  if (gAllocLog && loggingThisType && loggingThisObject) {
+    fprintf(gAllocLog, "\n<%s> %p %" PRIdPTR " Ctor (%d)\n", aType, aPtr,
+            serialno, aInstanceSize);
+    WalkTheStackCached(gAllocLog, CallerPC());
+  }
+}
+
+EXPORT_XPCOM_API(MOZ_NEVER_INLINE void)
+NS_LogDtor(void* aPtr, const char* aType, uint32_t aInstanceSize) {
+  ASSERT_ACTIVITY_IS_LEGAL(aType, "destroyed");
+  if (!gInitialized) {
+    InitTraceLog();
+  }
+
+  if (gLogging == NoLogging) {
+    return;
+  }
+
+  AutoTraceLogLock lock(gTraceLog);
+
+  if (gBloatLog) {
+    BloatEntry* entry = GetBloatEntry(aType, aInstanceSize);
+    if (entry) {
+      entry->Dtor();
+    }
+  }
+
+  bool loggingThisType = (!gTypesToLog || gTypesToLog->Contains(aType));
+  intptr_t serialno = 0;
+  if (gSerialNumbers && loggingThisType) {
+    serialno = GetSerialNumber(aPtr, false, CallerPC());
+    MOZ_ASSERT(serialno != 0,
+               "Serial number requested for unrecognized pointer!  "
+               "Are you memmoving a MOZ_COUNT_CTOR-tracked object?");
+    RecycleSerialNumberPtr(aPtr);
+  }
+
+  bool loggingThisObject = (!gObjectsToLog || LogThisObj(serialno));
+
+  // (If we're on a losing architecture, don't do this because we'll be
+  // using LogDeleteXPCOM instead to get file and line numbers.)
+  if (gAllocLog && loggingThisType && loggingThisObject) {
+    fprintf(gAllocLog, "\n<%s> %p %" PRIdPTR " Dtor (%d)\n", aType, aPtr,
+            serialno, aInstanceSize);
+    WalkTheStackCached(gAllocLog, CallerPC());
+  }
+}
+
+EXPORT_XPCOM_API(MOZ_NEVER_INLINE void)
+NS_LogCOMPtrAddRef(void* aCOMPtr, nsISupports* aObject) {
+#ifdef HAVE_CPP_DYNAMIC_CAST_TO_VOID_PTR
+  // Get the most-derived object.
+  void* object = dynamic_cast<void*>(aObject);
+
+  // This is a very indirect way of finding out what the class is
+  // of the object being logged.  If we're logging a specific type,
+  // then
+  if (!gTypesToLog || !gSerialNumbers) {
+    return;
+  }
+  if (!gInitialized) {
+    InitTraceLog();
+  }
+  if (gLogging == FullLogging) {
+    AutoTraceLogLock lock(gTraceLog);
+
+    intptr_t serialno = GetSerialNumber(object, false, CallerPC());
+    if (serialno == 0) {
+      return;
+    }
+
+    auto record = gSerialNumbers->Get(object);
+    int32_t count = record ? ++record->COMPtrCount : -1;
+    bool loggingThisObject = (!gObjectsToLog || LogThisObj(serialno));
+
+    if (gCOMPtrLog && loggingThisObject) {
+      fprintf(gCOMPtrLog, "\n<?> %p %" PRIdPTR " nsCOMPtrAddRef %d %p\n",
+              object, serialno, count, aCOMPtr);
+      WalkTheStackCached(gCOMPtrLog, CallerPC());
+    }
+  }
+#endif  // HAVE_CPP_DYNAMIC_CAST_TO_VOID_PTR
+}
+
+EXPORT_XPCOM_API(MOZ_NEVER_INLINE void)
+NS_LogCOMPtrRelease(void* aCOMPtr, nsISupports* aObject) {
+#ifdef HAVE_CPP_DYNAMIC_CAST_TO_VOID_PTR
+  // Get the most-derived object.
+  void* object = dynamic_cast<void*>(aObject);
+
+  // This is a very indirect way of finding out what the class is
+  // of the object being logged.  If we're logging a specific type,
+  // then
+  if (!gTypesToLog || !gSerialNumbers) {
+    return;
+  }
+  if (!gInitialized) {
+    InitTraceLog();
+  }
+  if (gLogging == FullLogging) {
+    AutoTraceLogLock lock(gTraceLog);
+
+    intptr_t serialno = GetSerialNumber(object, false, CallerPC());
+    if (serialno == 0) {
+      return;
+    }
+
+    auto record = gSerialNumbers->Get(object);
+    int32_t count = record ? --record->COMPtrCount : -1;
+    bool loggingThisObject = (!gObjectsToLog || LogThisObj(serialno));
+
+    if (gCOMPtrLog && loggingThisObject) {
+      fprintf(gCOMPtrLog, "\n<?> %p %" PRIdPTR " nsCOMPtrRelease %d %p\n",
+              object, serialno, count, aCOMPtr);
+      WalkTheStackCached(gCOMPtrLog, CallerPC());
+    }
+  }
+#endif  // HAVE_CPP_DYNAMIC_CAST_TO_VOID_PTR
+}
+
+static void ClearLogs(bool aKeepCounters) {
+  gCodeAddressService = nullptr;
+  // These counters from the fork server process will be preserved
+  // for the content processes to keep them consistent.
+  if (!aKeepCounters) {
+    gBloatView = nullptr;
+    gTypesToLog = nullptr;
+    gSerialNumbers = nullptr;
+  }
+  gObjectsToLog = nullptr;
+  gLogJSStacks = false;
+  gLogLeaksOnly = false;
+  maybeUnregisterAndCloseFile(gBloatLog);
+  maybeUnregisterAndCloseFile(gRefcntsLog);
+  maybeUnregisterAndCloseFile(gAllocLog);
+  maybeUnregisterAndCloseFile(gCOMPtrLog);
+}
+
+void nsTraceRefcnt::Shutdown() { ClearLogs(false); }
+
+void nsTraceRefcnt::SetActivityIsLegal(bool aLegal) {
+  if (gActivityTLS == BAD_TLS_INDEX) {
+    PR_NewThreadPrivateIndex(&gActivityTLS, nullptr);
+  }
+
+  PR_SetThreadPrivate(gActivityTLS, reinterpret_cast<void*>(!aLegal));
+}
+
+void nsTraceRefcnt::StartLoggingClass(const char* aClass) {
+  gLogging = FullLogging;
+
+  if (!gTypesToLog) {
+    gTypesToLog = new CharPtrSet(256);
+  }
+
+  fprintf(stdout, "### StartLoggingClass %s\n", aClass);
+  if (!gTypesToLog->Contains(aClass)) {
+    gTypesToLog->PutEntry(aClass);
+  }
+
+  // We are deliberately not initializing gSerialNumbers here, because
+  // it would cause assertions. gObjectsToLog can't be used because it
+  // relies on serial numbers.
+
+#ifdef XP_WIN
+#  define ENVVAR(x) u"" x
+#else
+#  define ENVVAR(x) x
+#endif
+
+  if (!gRefcntsLog) {
+    InitLog(ENVVAR("XPCOM_MEM_LATE_REFCNT_LOG"), "refcounts", &gRefcntsLog,
+            XRE_GetProcessTypeString());
+  }
+
+#undef ENVVAR
+}
+
+#ifdef MOZ_ENABLE_FORKSERVER
+void nsTraceRefcnt::ResetLogFiles(const char* aProcType) {
+  AutoRestore<LoggingType> saveLogging(gLogging);
+  gLogging = NoLogging;
+
+  ClearLogs(true);
+
+  // Create log files with the correct process type in the name.
+  DoInitTraceLog(aProcType);
+}
+#endif