path: root/xpcom/base/nsTraceRefcnt.cpp

/* -*- 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() = default;

 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