Add m-esr52 at 52.6.0

12 files changed, 1247 insertions, 0 deletions

diff --git a/tools/memory-profiler/CompactTraceTable.h b/tools/memory-profiler/CompactTraceTable.h
new file mode 100644
index 0000000000..5a6bd7e5c6
--- /dev/null
+++ b/tools/memory-profiler/CompactTraceTable.h
@@ -0,0 +1,116 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=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/. */
+
+#ifndef memory_profiler_CompactTraceTable_h
+#define memory_profiler_CompactTraceTable_h
+
+#include "mozilla/HashFunctions.h"
+
+#include "nsDataHashtable.h"
+#include "nsTArray.h"
+
+namespace mozilla {
+
+struct TrieNode final
+{
+  uint32_t parentIdx;
+  uint32_t nameIdx;
+  bool operator==(const TrieNode t) const
+  {
+    return parentIdx == t.parentIdx && nameIdx == t.nameIdx;
+  }
+  uint32_t Hash() const
+  {
+    return HashGeneric(parentIdx, nameIdx);
+  }
+};
+
+// This class maps a Node of type T to its parent's index in the
+// map. When serializing, the map is traversed and put into an ordered
+// array of Nodes.
+template<typename KeyClass, typename T>
+class NodeIndexMap final
+{
+public:
+  uint32_t Insert(const T& e)
+  {
+    uint32_t index = mMap.Count();
+    if (!mMap.Get(e, &index)) {
+      mMap.Put(e, index);
+    }
+    return index;
+  }
+
+  nsTArray<T> Serialize() const
+  {
+    nsTArray<T> v;
+    v.SetLength(mMap.Count());
+    for (auto iter = mMap.ConstIter(); !iter.Done(); iter.Next()) {
+      v[iter.Data()] = iter.Key();
+    }
+    return v;
+  }
+
+  uint32_t Size() const
+  {
+    return mMap.Count();
+  }
+
+  void Clear()
+  {
+    mMap.Clear();
+  }
+private:
+  nsDataHashtable<KeyClass, uint32_t> mMap;
+};
+
+// Backtraces are stored in a trie to save spaces.
+// Function names are stored in an unique table and TrieNodes contain indexes
+// into that table.
+// The trie is implemented with a hash table; children are stored in
+// traces[TrieNode{parent node index, branch/function name index}].
+class CompactTraceTable final
+{
+public:
+  CompactTraceTable()
+  {
+    mNames.Insert(nsAutoCString("(unknown)"));
+    mTraces.Insert(TrieNode{0, 0});
+  }
+
+  nsTArray<nsCString> GetNames() const
+  {
+    return mNames.Serialize();
+  }
+
+  nsTArray<TrieNode> GetTraces() const
+  {
+    return mTraces.Serialize();
+  }
+
+  // Returns an ID to a stacktrace.
+  uint32_t Insert(const nsTArray<nsCString>& aRawStacktrace)
+  {
+    uint32_t parent = 0;
+    for (auto& frame: aRawStacktrace) {
+      parent = mTraces.Insert(TrieNode{parent, mNames.Insert(frame)});
+    }
+    return parent;
+  }
+
+  void Reset()
+  {
+    mNames.Clear();
+    mTraces.Clear();
+  }
+private:
+  NodeIndexMap<nsCStringHashKey, nsCString> mNames;
+  NodeIndexMap<nsGenericHashKey<TrieNode>, TrieNode> mTraces;
+};
+
+} // namespace mozilla
+
+#endif // memory_profiler_CompactTraceTable_h
diff --git a/tools/memory-profiler/GCHeapProfilerImpl.cpp b/tools/memory-profiler/GCHeapProfilerImpl.cpp
new file mode 100644
index 0000000000..528a055011
--- /dev/null
+++ b/tools/memory-profiler/GCHeapProfilerImpl.cpp
@@ -0,0 +1,168 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=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 "GCHeapProfilerImpl.h"
+
+#include "UncensoredAllocator.h"
+
+namespace mozilla {
+
+GCHeapProfilerImpl::GCHeapProfilerImpl()
+{
+  mLock = PR_NewLock();
+  mMarking = false;
+}
+
+GCHeapProfilerImpl::~GCHeapProfilerImpl()
+{
+  if (mLock) {
+    PR_DestroyLock(mLock);
+  }
+}
+
+nsTArray<nsCString>
+GCHeapProfilerImpl::GetNames() const
+{
+  return mTraceTable.GetNames();
+}
+
+nsTArray<TrieNode>
+GCHeapProfilerImpl::GetTraces() const
+{
+  return mTraceTable.GetTraces();
+}
+
+const nsTArray<AllocEvent>&
+GCHeapProfilerImpl::GetEvents() const
+{
+  return mAllocEvents;
+}
+
+void
+GCHeapProfilerImpl::reset()
+{
+  mTraceTable.Reset();
+  mAllocEvents.Clear();
+  mNurseryEntries.Clear();
+  mTenuredEntriesFG.Clear();
+  mTenuredEntriesBG.Clear();
+}
+
+void
+GCHeapProfilerImpl::sampleTenured(void* addr, uint32_t size)
+{
+  SampleInternal(addr, size, mTenuredEntriesFG);
+}
+
+void
+GCHeapProfilerImpl::sampleNursery(void* addr, uint32_t size)
+{
+  SampleInternal(addr, size, mNurseryEntries);
+}
+
+void
+GCHeapProfilerImpl::markTenuredStart()
+{
+  AutoUseUncensoredAllocator ua;
+  AutoMPLock lock(mLock);
+  if (!mMarking) {
+    mMarking = true;
+    mTenuredEntriesFG.SwapElements(mTenuredEntriesBG);
+    MOZ_ASSERT(mTenuredEntriesFG.Count() == 0);
+  }
+}
+
+void
+GCHeapProfilerImpl::markTenured(void* addr)
+{
+  AutoUseUncensoredAllocator ua;
+  AutoMPLock lock(mLock);
+  if (mMarking) {
+    AllocEntry entry;
+    if (mTenuredEntriesBG.Get(addr, &entry)) {
+      entry.mMarked = true;
+      mTenuredEntriesBG.Put(addr, entry);
+    }
+  }
+}
+
+void
+GCHeapProfilerImpl::sweepTenured()
+{
+  AutoUseUncensoredAllocator ua;
+  AutoMPLock lock(mLock);
+  if (mMarking) {
+    mMarking = false;
+    for (auto iter = mTenuredEntriesBG.Iter(); !iter.Done(); iter.Next()) {
+      if (iter.Data().mMarked) {
+        iter.Data().mMarked = false;
+        mTenuredEntriesFG.Put(iter.Key(), iter.Data());
+      } else {
+        AllocEvent& oldEvent = mAllocEvents[iter.Data().mEventIdx];
+        AllocEvent newEvent(oldEvent.mTraceIdx, -oldEvent.mSize, TimeStamp::Now());
+        mAllocEvents.AppendElement(newEvent);
+      }
+    }
+    mTenuredEntriesBG.Clear();
+  }
+}
+
+void
+GCHeapProfilerImpl::sweepNursery()
+{
+  AutoUseUncensoredAllocator ua;
+  AutoMPLock lock(mLock);
+  for (auto iter = mNurseryEntries.Iter(); !iter.Done(); iter.Next()) {
+    AllocEvent& oldEvent = mAllocEvents[iter.Data().mEventIdx];
+    AllocEvent newEvent(oldEvent.mTraceIdx, -oldEvent.mSize, TimeStamp::Now());
+    mAllocEvents.AppendElement(newEvent);
+  }
+  mNurseryEntries.Clear();
+}
+
+void
+GCHeapProfilerImpl::moveNurseryToTenured(void* addrOld, void* addrNew)
+{
+  AutoUseUncensoredAllocator ua;
+  AutoMPLock lock(mLock);
+  AllocEntry entryOld;
+  if (!mNurseryEntries.Get(addrOld, &entryOld)) {
+    return;
+  }
+
+  // Because the tenured heap is sampled, the address might already be there.
+  // If not, the address is inserted with the old event.
+  AllocEntry tenuredEntryOld;
+  if (!mTenuredEntriesFG.Get(addrNew, &tenuredEntryOld)) {
+    mTenuredEntriesFG.Put(addrNew, AllocEntry(entryOld.mEventIdx));
+  } else {
+    // If it is already inserted, the insertion above will fail and the
+    // iterator of the already-inserted element is returned.
+    // We choose to ignore the the new event by setting its size zero and point
+    // the newly allocated address to the old event.
+    // An event of size zero will be skipped when reporting.
+    mAllocEvents[entryOld.mEventIdx].mSize = 0;
+    tenuredEntryOld.mEventIdx = entryOld.mEventIdx;
+    mTenuredEntriesFG.Put(addrNew, tenuredEntryOld);
+  }
+  mNurseryEntries.Remove(addrOld);
+}
+
+void
+GCHeapProfilerImpl::SampleInternal(void* aAddr, uint32_t aSize, AllocMap& aTable)
+{
+  AutoUseUncensoredAllocator ua;
+  AutoMPLock lock(mLock);
+  size_t nSamples = AddBytesSampled(aSize);
+  if (nSamples > 0) {
+    nsTArray<nsCString> trace = GetStacktrace();
+    AllocEvent ai(mTraceTable.Insert(trace), nSamples * mSampleSize, TimeStamp::Now());
+    aTable.Put(aAddr, AllocEntry(mAllocEvents.Length()));
+    mAllocEvents.AppendElement(ai);
+  }
+}
+
+} // namespace mozilla
diff --git a/tools/memory-profiler/GCHeapProfilerImpl.h b/tools/memory-profiler/GCHeapProfilerImpl.h
new file mode 100644
index 0000000000..e84e970177
--- /dev/null
+++ b/tools/memory-profiler/GCHeapProfilerImpl.h
@@ -0,0 +1,53 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=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/. */
+
+#ifndef memory_profiler_GCHeapProfilerImpl_h
+#define memory_profiler_GCHeapProfilerImpl_h
+
+#include "CompactTraceTable.h"
+#include "MemoryProfiler.h"
+
+#include "jsfriendapi.h"
+
+namespace mozilla {
+
+class GCHeapProfilerImpl final : public GCHeapProfiler
+                               , public ProfilerImpl
+{
+public:
+  GCHeapProfilerImpl();
+  ~GCHeapProfilerImpl() override;
+
+  nsTArray<nsCString> GetNames() const override;
+  nsTArray<TrieNode> GetTraces() const override;
+  const nsTArray<AllocEvent>& GetEvents() const override;
+
+  void reset() override;
+  void sampleTenured(void* addr, uint32_t size) override;
+  void sampleNursery(void* addr, uint32_t size) override;
+  void markTenuredStart() override;
+  void markTenured(void* addr) override;
+  void sweepTenured() override;
+  void sweepNursery() override;
+  void moveNurseryToTenured(void* addrOld, void* addrNew) override;
+
+private:
+  void SampleInternal(void* addr, uint32_t size, AllocMap& table);
+
+  PRLock* mLock;
+  bool mMarking;
+
+  AllocMap mNurseryEntries;
+  AllocMap mTenuredEntriesFG;
+  AllocMap mTenuredEntriesBG;
+
+  nsTArray<AllocEvent> mAllocEvents;
+  CompactTraceTable mTraceTable;
+};
+
+} // namespace mozilla
+
+#endif // memory_profiler_GCHeapProfilerImpl_h
diff --git a/tools/memory-profiler/MemoryProfiler.cpp b/tools/memory-profiler/MemoryProfiler.cpp
new file mode 100644
index 0000000000..c2b8cbd1d1
--- /dev/null
+++ b/tools/memory-profiler/MemoryProfiler.cpp
@@ -0,0 +1,324 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=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 "MemoryProfiler.h"
+
+#include <cmath>
+#include <cstdlib>
+
+#include "mozilla/ClearOnShutdown.h"
+#include "mozilla/Move.h"
+#include "mozilla/TimeStamp.h"
+#include "mozilla/UniquePtr.h"
+
+#include "GCHeapProfilerImpl.h"
+#include "GeckoProfiler.h"
+#include "NativeProfilerImpl.h"
+#include "UncensoredAllocator.h"
+#include "js/TypeDecls.h"
+#include "jsfriendapi.h"
+#include "nsIDOMClassInfo.h"
+#include "nsIGlobalObject.h"
+#include "prtime.h"
+#include "xpcprivate.h"
+
+namespace mozilla {
+
+#define MEMORY_PROFILER_SAMPLE_SIZE 65536
+#define BACKTRACE_BUFFER_SIZE 16384
+
+ProfilerImpl::ProfilerImpl()
+  : mSampleSize(MEMORY_PROFILER_SAMPLE_SIZE)
+{
+  mLog1minusP = std::log(1.0 - 1.0 / mSampleSize);
+  mRemainingBytes = std::floor(std::log(1.0 - DRandom()) / mLog1minusP);
+}
+
+nsTArray<nsCString>
+ProfilerImpl::GetStacktrace()
+{
+  nsTArray<nsCString> trace;
+  auto output = MakeUnique<char[]>(BACKTRACE_BUFFER_SIZE);
+
+  profiler_get_backtrace_noalloc(output.get(), BACKTRACE_BUFFER_SIZE);
+  for (const char* p = output.get(); *p; p += strlen(p) + 1) {
+    trace.AppendElement()->Assign(p);
+  }
+
+  return trace;
+}
+
+// Generate a random number in [0, 1).
+double
+ProfilerImpl::DRandom()
+{
+  return double(((uint64_t(std::rand()) & ((1 << 26) - 1)) << 27) +
+                (uint64_t(std::rand()) & ((1 << 27) - 1)))
+    / (uint64_t(1) << 53);
+}
+
+size_t
+ProfilerImpl::AddBytesSampled(uint32_t aBytes)
+{
+  size_t nSamples = 0;
+  while (mRemainingBytes <= aBytes) {
+    mRemainingBytes += std::floor(std::log(1.0 - DRandom()) / mLog1minusP);
+    nSamples++;
+  }
+  mRemainingBytes -= aBytes;
+  return nSamples;
+}
+
+NS_IMPL_ISUPPORTS(MemoryProfiler, nsIMemoryProfiler)
+
+PRLock* MemoryProfiler::sLock;
+uint32_t MemoryProfiler::sProfileContextCount;
+StaticAutoPtr<NativeProfilerImpl> MemoryProfiler::sNativeProfiler;
+StaticAutoPtr<JSContextProfilerMap> MemoryProfiler::sJSContextProfilerMap;
+TimeStamp MemoryProfiler::sStartTime;
+
+void
+MemoryProfiler::InitOnce()
+{
+  MOZ_ASSERT(NS_IsMainThread());
+
+  static bool initialized = false;
+
+  if (!initialized) {
+    MallocHook::Initialize();
+    sLock = PR_NewLock();
+    sProfileContextCount = 0;
+    sJSContextProfilerMap = new JSContextProfilerMap();
+    ClearOnShutdown(&sJSContextProfilerMap);
+    ClearOnShutdown(&sNativeProfiler);
+    std::srand(PR_Now());
+    bool ignored;
+    sStartTime = TimeStamp::ProcessCreation(ignored);
+    initialized = true;
+  }
+}
+
+NS_IMETHODIMP
+MemoryProfiler::StartProfiler()
+{
+  InitOnce();
+  AutoUseUncensoredAllocator ua;
+  AutoMPLock lock(sLock);
+  JSContext* context = XPCJSContext::Get()->Context();
+  ProfilerForJSContext profiler;
+  if (!sJSContextProfilerMap->Get(context, &profiler) ||
+      !profiler.mEnabled) {
+    if (sProfileContextCount == 0) {
+      js::EnableContextProfilingStack(context, true);
+      if (!sNativeProfiler) {
+        sNativeProfiler = new NativeProfilerImpl();
+      }
+      MemProfiler::SetNativeProfiler(sNativeProfiler);
+    }
+    GCHeapProfilerImpl* gp = new GCHeapProfilerImpl();
+    profiler.mEnabled = true;
+    profiler.mProfiler = gp;
+    sJSContextProfilerMap->Put(context, profiler);
+    MemProfiler::GetMemProfiler(context)->start(gp);
+    if (sProfileContextCount == 0) {
+      MallocHook::Enable(sNativeProfiler);
+    }
+    sProfileContextCount++;
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+MemoryProfiler::StopProfiler()
+{
+  InitOnce();
+  AutoUseUncensoredAllocator ua;
+  AutoMPLock lock(sLock);
+  JSContext* context = XPCJSContext::Get()->Context();
+  ProfilerForJSContext profiler;
+  if (sJSContextProfilerMap->Get(context, &profiler) &&
+      profiler.mEnabled) {
+    MemProfiler::GetMemProfiler(context)->stop();
+    if (--sProfileContextCount == 0) {
+      MallocHook::Disable();
+      MemProfiler::SetNativeProfiler(nullptr);
+      js::EnableContextProfilingStack(context, false);
+    }
+    profiler.mEnabled = false;
+    sJSContextProfilerMap->Put(context, profiler);
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+MemoryProfiler::ResetProfiler()
+{
+  InitOnce();
+  AutoUseUncensoredAllocator ua;
+  AutoMPLock lock(sLock);
+  JSContext* context = XPCJSContext::Get()->Context();
+  ProfilerForJSContext profiler;
+  if (!sJSContextProfilerMap->Get(context, &profiler) ||
+      !profiler.mEnabled) {
+    delete profiler.mProfiler;
+    profiler.mProfiler = nullptr;
+    sJSContextProfilerMap->Put(context, profiler);
+  }
+  if (sProfileContextCount == 0) {
+    sNativeProfiler = nullptr;
+  }
+  return NS_OK;
+}
+
+struct MergedTraces
+{
+  nsTArray<nsCString> mNames;
+  nsTArray<TrieNode> mTraces;
+  nsTArray<AllocEvent> mEvents;
+};
+
+// Merge events and corresponding traces and names.
+static MergedTraces
+MergeResults(const nsTArray<nsCString>& names0,
+             const nsTArray<TrieNode>& traces0,
+             const nsTArray<AllocEvent>& events0,
+             const nsTArray<nsCString>& names1,
+             const nsTArray<TrieNode>& traces1,
+             const nsTArray<AllocEvent>& events1)
+{
+  NodeIndexMap<nsCStringHashKey, nsCString> names;
+  NodeIndexMap<nsGenericHashKey<TrieNode>, TrieNode> traces;
+  nsTArray<AllocEvent> events;
+
+  nsTArray<size_t> names1Tonames0(names1.Length());
+  nsTArray<size_t> traces1Totraces0(traces1.Length());
+
+  // Merge names.
+  for (auto& i: names0) {
+    names.Insert(i);
+  }
+  for (auto& i: names1) {
+    names1Tonames0.AppendElement(names.Insert(i));
+  }
+
+  // Merge traces. Note that traces1[i].parentIdx < i for all i > 0.
+  for (auto& i: traces0) {
+    traces.Insert(i);
+  }
+  traces1Totraces0.AppendElement(0);
+  for (size_t i = 1; i < traces1.Length(); i++) {
+    TrieNode node = traces1[i];
+    node.parentIdx = traces1Totraces0[node.parentIdx];
+    node.nameIdx = names1Tonames0[node.nameIdx];
+    traces1Totraces0.AppendElement(traces.Insert(node));
+  }
+
+  // Merge the events according to timestamps.
+  auto p0 = events0.begin();
+  auto p1 = events1.begin();
+
+  while (p0 != events0.end() && p1 != events1.end()) {
+    if (p0->mTimestamp < p1->mTimestamp) {
+      events.AppendElement(*p0++);
+    } else {
+      events.AppendElement(*p1++);
+      events.LastElement().mTraceIdx =
+        traces1Totraces0[events.LastElement().mTraceIdx];
+    }
+  }
+
+  while (p0 != events0.end()) {
+    events.AppendElement(*p0++);
+  }
+
+  while (p1 != events1.end()) {
+    events.AppendElement(*p1++);
+    events.LastElement().mTraceIdx =
+      traces1Totraces0[events.LastElement().mTraceIdx];
+  }
+
+  return MergedTraces{names.Serialize(), traces.Serialize(), Move(events)};
+}
+
+NS_IMETHODIMP
+MemoryProfiler::GetResults(JSContext* cx, JS::MutableHandle<JS::Value> aResult)
+{
+  InitOnce();
+  AutoUseUncensoredAllocator ua;
+  AutoMPLock lock(sLock);
+  JSContext* context = XPCJSContext::Get()->Context();
+  // Getting results when the profiler is running is not allowed.
+  if (sProfileContextCount > 0) {
+    return NS_OK;
+  }
+  // Return immediately when native profiler does not exist.
+  if (!sNativeProfiler) {
+    return NS_OK;
+  }
+  // Return immediately when there's no result in current context.
+  ProfilerForJSContext profiler;
+  if (!sJSContextProfilerMap->Get(context, &profiler) ||
+      !profiler.mProfiler) {
+    return NS_OK;
+  }
+  GCHeapProfilerImpl* gp = profiler.mProfiler;
+
+  auto results = MergeResults(gp->GetNames(), gp->GetTraces(), gp->GetEvents(),
+                              sNativeProfiler->GetNames(),
+                              sNativeProfiler->GetTraces(),
+                              sNativeProfiler->GetEvents());
+  const nsTArray<nsCString>& names = results.mNames;
+  const nsTArray<TrieNode>& traces = results.mTraces;
+  const nsTArray<AllocEvent>& events = results.mEvents;
+
+  JS::RootedObject jsnames(cx, JS_NewArrayObject(cx, names.Length()));
+  JS::RootedObject jstraces(cx, JS_NewArrayObject(cx, traces.Length()));
+  JS::RootedObject jsevents(cx, JS_NewArrayObject(cx, events.Length()));
+
+  for (size_t i = 0; i < names.Length(); i++) {
+    JS::RootedString name(cx, JS_NewStringCopyZ(cx, names[i].get()));
+    JS_SetElement(cx, jsnames, i, name);
+  }
+
+  for (size_t i = 0; i < traces.Length(); i++) {
+    JS::RootedObject tn(cx, JS_NewPlainObject(cx));
+    JS::RootedValue nameIdx(cx, JS_NumberValue(traces[i].nameIdx));
+    JS::RootedValue parentIdx(cx, JS_NumberValue(traces[i].parentIdx));
+    JS_SetProperty(cx, tn, "nameIdx", nameIdx);
+    JS_SetProperty(cx, tn, "parentIdx", parentIdx);
+    JS_SetElement(cx, jstraces, i, tn);
+  }
+
+  int i = 0;
+  for (auto ent: events) {
+    if (ent.mSize == 0) {
+      continue;
+    }
+    MOZ_ASSERT(!sStartTime.IsNull());
+    double time = (ent.mTimestamp - sStartTime).ToMilliseconds();
+    JS::RootedObject tn(cx, JS_NewPlainObject(cx));
+    JS::RootedValue size(cx, JS_NumberValue(ent.mSize));
+    JS::RootedValue traceIdx(cx, JS_NumberValue(ent.mTraceIdx));
+    JS::RootedValue timestamp(cx, JS_NumberValue(time));
+    JS_SetProperty(cx, tn, "size", size);
+    JS_SetProperty(cx, tn, "traceIdx", traceIdx);
+    JS_SetProperty(cx, tn, "timestamp", timestamp);
+    JS_SetElement(cx, jsevents, i++, tn);
+  }
+  JS_SetArrayLength(cx, jsevents, i);
+
+  JS::RootedObject result(cx, JS_NewPlainObject(cx));
+  JS::RootedValue objnames(cx, ObjectOrNullValue(jsnames));
+  JS_SetProperty(cx, result, "names", objnames);
+  JS::RootedValue objtraces(cx, ObjectOrNullValue(jstraces));
+  JS_SetProperty(cx, result, "traces", objtraces);
+  JS::RootedValue objevents(cx, ObjectOrNullValue(jsevents));
+  JS_SetProperty(cx, result, "events", objevents);
+  aResult.setObject(*result);
+  return NS_OK;
+}
+
+} // namespace mozilla
diff --git a/tools/memory-profiler/MemoryProfiler.h b/tools/memory-profiler/MemoryProfiler.h
new file mode 100644
index 0000000000..85a378fb23
--- /dev/null
+++ b/tools/memory-profiler/MemoryProfiler.h
@@ -0,0 +1,159 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=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/. */
+
+#ifndef tools_profiler_MemoryProfiler_h
+#define tools_profiler_MemoryProfiler_h
+
+#include "nsIMemoryProfiler.h"
+
+#include "mozilla/StaticPtr.h"
+#include "mozilla/TimeStamp.h"
+
+#include "CompactTraceTable.h"
+#include "nsTArray.h"
+#include "prlock.h"
+
+#define MEMORY_PROFILER_CID                                     \
+  { 0xf976eaa2, 0xcc1f, 0x47ee,                                 \
+    { 0x81, 0x29, 0xb8, 0x26, 0x2a, 0x3d, 0xb6, 0xb2 } }
+
+#define MEMORY_PROFILER_CONTRACT_ID "@mozilla.org/tools/memory-profiler;1"
+
+struct PRLock;
+
+namespace mozilla {
+
+class NativeProfilerImpl;
+class GCHeapProfilerImpl;
+
+struct ProfilerForJSContext
+{
+  ProfilerForJSContext()
+    : mProfiler(nullptr)
+    , mEnabled(false)
+  {}
+  GCHeapProfilerImpl* mProfiler;
+  bool mEnabled;
+};
+using JSContextProfilerMap =
+  nsDataHashtable<nsClearingPtrHashKey<JSContext>, ProfilerForJSContext>;
+
+class MemoryProfiler final : public nsIMemoryProfiler
+{
+public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIMEMORYPROFILER
+
+private:
+  static void InitOnce();
+  ~MemoryProfiler() {}
+
+  // The accesses to other static member are guarded by sLock and
+  // sProfileContextCount.
+  static PRLock* sLock;
+  static uint32_t sProfileContextCount;
+
+  static StaticAutoPtr<NativeProfilerImpl> sNativeProfiler;
+  static StaticAutoPtr<JSContextProfilerMap> sJSContextProfilerMap;
+  static TimeStamp sStartTime;
+};
+
+// Allocation events to be reported.
+struct AllocEvent {
+  TimeStamp mTimestamp;
+  // index to a stacktrace singleton.
+  uint32_t mTraceIdx;
+  // Allocation size
+  int32_t mSize;
+
+  AllocEvent(uint32_t aTraceIdx, int32_t aSize, TimeStamp aTimestamp)
+    : mTimestamp(aTimestamp)
+    , mTraceIdx(aTraceIdx)
+    , mSize(aSize)
+  {}
+};
+
+// Index to allocation events but also a mark bit to be GC-able.
+struct AllocEntry {
+  uint32_t mEventIdx : 31;
+  bool mMarked : 1;
+
+  // Default constructor for uninitialized stack value required by
+  // getter methods.
+  AllocEntry()
+    : mEventIdx(0)
+    , mMarked(false)
+  {}
+  explicit AllocEntry(int aEventIdx)
+    : mEventIdx(aEventIdx)
+    , mMarked(false)
+  {}
+};
+
+using AllocMap = nsDataHashtable<nsClearingVoidPtrHashKey, AllocEntry>;
+
+class ProfilerImpl
+{
+public:
+  static nsTArray<nsCString> GetStacktrace();
+  static double DRandom();
+
+  ProfilerImpl();
+  virtual nsTArray<nsCString> GetNames() const = 0;
+  virtual nsTArray<TrieNode> GetTraces() const = 0;
+  virtual const nsTArray<AllocEvent>& GetEvents() const = 0;
+
+protected:
+  /**
+   * The sampler generates a random variable which conforms to a geometric
+   * distribution of probability p = 1 / mSampleSize to calculate the
+   * next-to-be-sampled byte directly; It avoids rolling a dice on each byte.
+   *
+   * Let Bn denote a Bernoulli process with first success on n-th trial, the
+   * cumulative distribution function of Bn is Cn = 1 - (1 - p) ^ n.
+   * Let U denote a uniformly distributed random variable in [0, 1).
+   * A geometric random variable can be generated by Cn's reverse function:
+   * G = floor(log(1 - U) / log(1 - p)).
+   *
+   * @param aSize the number of bytes seen
+   * @return the number of events sampled
+   */
+  size_t AddBytesSampled(uint32_t aBytes);
+
+  uint32_t mSampleSize;
+
+private:
+  uint32_t mRemainingBytes;
+  double mLog1minusP;
+};
+
+/*
+ * This class is used to make sure the profile data is only accessed
+ * on one thread at a time. Don't use mozilla::Mutex because we don't
+ * want to allocate memory.
+ */
+class AutoMPLock
+{
+public:
+  explicit AutoMPLock(PRLock* aLock)
+  {
+    MOZ_ASSERT(aLock);
+    mLock = aLock;
+    PR_Lock(mLock);
+  }
+
+  ~AutoMPLock()
+  {
+    PR_Unlock(mLock);
+  }
+
+private:
+  PRLock* mLock;
+};
+
+} // namespace mozilla
+
+#endif
diff --git a/tools/memory-profiler/NativeProfilerImpl.cpp b/tools/memory-profiler/NativeProfilerImpl.cpp
new file mode 100644
index 0000000000..48c684c727
--- /dev/null
+++ b/tools/memory-profiler/NativeProfilerImpl.cpp
@@ -0,0 +1,82 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=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 "NativeProfilerImpl.h"
+
+#include "UncensoredAllocator.h"
+
+namespace mozilla {
+
+NativeProfilerImpl::NativeProfilerImpl()
+{
+  mLock = PR_NewLock();
+}
+
+NativeProfilerImpl::~NativeProfilerImpl()
+{
+  if (mLock) {
+    PR_DestroyLock(mLock);
+  }
+}
+
+nsTArray<nsCString>
+NativeProfilerImpl::GetNames() const
+{
+  return mTraceTable.GetNames();
+}
+
+nsTArray<TrieNode>
+NativeProfilerImpl::GetTraces() const
+{
+  return mTraceTable.GetTraces();
+}
+
+const nsTArray<AllocEvent>&
+NativeProfilerImpl::GetEvents() const
+{
+  return mAllocEvents;
+}
+
+void
+NativeProfilerImpl::reset()
+{
+  mTraceTable.Reset();
+  mAllocEvents.Clear();
+  mNativeEntries.Clear();
+}
+
+void
+NativeProfilerImpl::sampleNative(void* addr, uint32_t size)
+{
+  AutoUseUncensoredAllocator ua;
+  AutoMPLock lock(mLock);
+  size_t nSamples = AddBytesSampled(size);
+  if (nSamples > 0) {
+    nsTArray<nsCString> trace = GetStacktrace();
+    AllocEvent ai(mTraceTable.Insert(trace), nSamples * mSampleSize, TimeStamp::Now());
+    mNativeEntries.Put(addr, AllocEntry(mAllocEvents.Length()));
+    mAllocEvents.AppendElement(ai);
+  }
+}
+
+void
+NativeProfilerImpl::removeNative(void* addr)
+{
+  AutoUseUncensoredAllocator ua;
+  AutoMPLock lock(mLock);
+
+  AllocEntry entry;
+  if (!mNativeEntries.Get(addr, &entry)) {
+    return;
+  }
+
+  AllocEvent& oldEvent = mAllocEvents[entry.mEventIdx];
+  AllocEvent newEvent(oldEvent.mTraceIdx, -oldEvent.mSize, TimeStamp::Now());
+  mAllocEvents.AppendElement(newEvent);
+  mNativeEntries.Remove(addr);
+}
+
+} // namespace mozilla
diff --git a/tools/memory-profiler/NativeProfilerImpl.h b/tools/memory-profiler/NativeProfilerImpl.h
new file mode 100644
index 0000000000..95cc2ec138
--- /dev/null
+++ b/tools/memory-profiler/NativeProfilerImpl.h
@@ -0,0 +1,43 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=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/. */
+
+#ifndef memory_profiler_NativeProfilerImpl_h
+#define memory_profiler_NativeProfilerImpl_h
+
+#include "CompactTraceTable.h"
+#include "MemoryProfiler.h"
+
+#include "jsfriendapi.h"
+
+struct PRLock;
+
+namespace mozilla {
+
+class NativeProfilerImpl final : public NativeProfiler
+                               , public ProfilerImpl
+{
+public:
+  NativeProfilerImpl();
+  ~NativeProfilerImpl() override;
+
+  nsTArray<nsCString> GetNames() const override;
+  nsTArray<TrieNode> GetTraces() const override;
+  const nsTArray<AllocEvent>& GetEvents() const override;
+
+  void reset() override;
+  void sampleNative(void* addr, uint32_t size) override;
+  void removeNative(void* addr) override;
+
+private:
+  PRLock* mLock;
+  AllocMap mNativeEntries;
+  nsTArray<AllocEvent> mAllocEvents;
+  CompactTraceTable mTraceTable;
+};
+
+} // namespace mozilla
+
+#endif // memory_profiler_NativeProfilerImpl_h
diff --git a/tools/memory-profiler/UncensoredAllocator.cpp b/tools/memory-profiler/UncensoredAllocator.cpp
new file mode 100644
index 0000000000..92caeb6337
--- /dev/null
+++ b/tools/memory-profiler/UncensoredAllocator.cpp
@@ -0,0 +1,121 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=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 "UncensoredAllocator.h"
+
+#include "mozilla/Assertions.h"
+#include "mozilla/Unused.h"
+
+#include "MainThreadUtils.h"
+#include "jsfriendapi.h"
+#include "nsDebug.h"
+#include "prlock.h"
+#ifdef MOZ_REPLACE_MALLOC
+#include "replace_malloc_bridge.h"
+#endif
+
+namespace mozilla {
+
+#ifdef MOZ_REPLACE_MALLOC
+MOZ_THREAD_LOCAL(bool) MallocHook::mEnabledTLS;
+NativeProfiler* MallocHook::mNativeProfiler;
+malloc_hook_table_t MallocHook::mMallocHook;
+#endif
+
+AutoUseUncensoredAllocator::AutoUseUncensoredAllocator()
+{
+#ifdef MOZ_REPLACE_MALLOC
+  MallocHook::mEnabledTLS.set(false);
+#endif
+}
+
+AutoUseUncensoredAllocator::~AutoUseUncensoredAllocator()
+{
+#ifdef MOZ_REPLACE_MALLOC
+  MallocHook::mEnabledTLS.set(true);
+#endif
+}
+
+bool
+MallocHook::Enabled()
+{
+#ifdef MOZ_REPLACE_MALLOC
+  return mEnabledTLS.get() && mNativeProfiler;
+#else
+  return false;
+#endif
+}
+
+void*
+MallocHook::SampleNative(void* aAddr, size_t aSize)
+{
+#ifdef MOZ_REPLACE_MALLOC
+  if (MallocHook::Enabled()) {
+    mNativeProfiler->sampleNative(aAddr, aSize);
+  }
+#endif
+  return aAddr;
+}
+
+void
+MallocHook::RemoveNative(void* aAddr)
+{
+#ifdef MOZ_REPLACE_MALLOC
+  if (MallocHook::Enabled()) {
+    mNativeProfiler->removeNative(aAddr);
+  }
+#endif
+}
+
+void
+MallocHook::Initialize()
+{
+#ifdef MOZ_REPLACE_MALLOC
+  MOZ_ASSERT(NS_IsMainThread());
+  mMallocHook.free_hook = RemoveNative;
+  mMallocHook.malloc_hook = SampleNative;
+  ReplaceMallocBridge* bridge = ReplaceMallocBridge::Get(3);
+  if (bridge) {
+    mozilla::Unused << bridge->RegisterHook("memory-profiler", nullptr, nullptr);
+  }
+
+  bool success = mEnabledTLS.init();
+  if (NS_WARN_IF(!success)) {
+    return;
+  }
+#endif
+}
+
+void
+MallocHook::Enable(NativeProfiler* aNativeProfiler)
+{
+#ifdef MOZ_REPLACE_MALLOC
+  MOZ_ASSERT(NS_IsMainThread());
+  ReplaceMallocBridge* bridge = ReplaceMallocBridge::Get(3);
+  if (bridge) {
+    const malloc_table_t* alloc_funcs =
+      bridge->RegisterHook("memory-profiler", nullptr, &mMallocHook);
+    if (alloc_funcs) {
+      mNativeProfiler = aNativeProfiler;
+    }
+  }
+#endif
+}
+
+void
+MallocHook::Disable()
+{
+#ifdef MOZ_REPLACE_MALLOC
+  MOZ_ASSERT(NS_IsMainThread());
+  ReplaceMallocBridge* bridge = ReplaceMallocBridge::Get(3);
+  if (bridge) {
+    bridge->RegisterHook("memory-profiler", nullptr, nullptr);
+    mNativeProfiler = nullptr;
+  }
+#endif
+}
+
+} // namespace mozilla
diff --git a/tools/memory-profiler/UncensoredAllocator.h b/tools/memory-profiler/UncensoredAllocator.h
new file mode 100644
index 0000000000..b9074c7386
--- /dev/null
+++ b/tools/memory-profiler/UncensoredAllocator.h
@@ -0,0 +1,48 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=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/. */
+
+#ifndef memory_profiler_UncensoredAllocator_h
+#define memory_profiler_UncensoredAllocator_h
+
+#include "mozilla/Attributes.h"
+#include "mozilla/ThreadLocal.h"
+
+#ifdef MOZ_REPLACE_MALLOC
+#include "replace_malloc_bridge.h"
+#endif
+
+class NativeProfiler;
+
+namespace mozilla {
+
+class MallocHook final
+{
+public:
+  static void Initialize();
+  static void Enable(NativeProfiler* aNativeProfiler);
+  static void Disable();
+  static bool Enabled();
+private:
+  static void* SampleNative(void* aAddr, size_t aSize);
+  static void RemoveNative(void* aAddr);
+#ifdef MOZ_REPLACE_MALLOC
+  static MOZ_THREAD_LOCAL(bool) mEnabledTLS;
+  static NativeProfiler* mNativeProfiler;
+  static malloc_hook_table_t mMallocHook;
+#endif
+  friend class AutoUseUncensoredAllocator;
+};
+
+class MOZ_RAII AutoUseUncensoredAllocator final
+{
+public:
+  AutoUseUncensoredAllocator();
+  ~AutoUseUncensoredAllocator();
+};
+
+} // namespace mozilla
+
+#endif // memory_profiler_UncensoredAllocator_h
diff --git a/tools/memory-profiler/moz.build b/tools/memory-profiler/moz.build
new file mode 100644
index 0000000000..be2fe74323
--- /dev/null
+++ b/tools/memory-profiler/moz.build
@@ -0,0 +1,29 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# 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/.
+
+if CONFIG['MOZ_ENABLE_PROFILER_SPS']:
+    XPIDL_MODULE = 'memory_profiler'
+    XPIDL_SOURCES += [
+        'nsIMemoryProfiler.idl',
+    ]
+
+    UNIFIED_SOURCES += [
+        'GCHeapProfilerImpl.cpp',
+        'MemoryProfiler.cpp',
+        'NativeProfilerImpl.cpp',
+        'nsMemoryProfilerFactory.cpp',
+        'UncensoredAllocator.cpp',
+    ]
+
+    LOCAL_INCLUDES += [
+        '/js/xpconnect/src',
+        '/xpcom/base',
+    ]
+
+    FINAL_LIBRARY = 'xul'
+
+if CONFIG['GNU_CXX']:
+    CXXFLAGS += ['-Wno-error=shadow']
diff --git a/tools/memory-profiler/nsIMemoryProfiler.idl b/tools/memory-profiler/nsIMemoryProfiler.idl
new file mode 100644
index 0000000000..4ca386f9d8
--- /dev/null
+++ b/tools/memory-profiler/nsIMemoryProfiler.idl
@@ -0,0 +1,72 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* 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 "nsISupports.idl"
+
+/**
+ * The memory profiler samples allocation events. An allocation event
+ * includes a type (what and at where is going to be allocated), a
+ * size, a timestamp and the corresponding stack trace. Free events
+ * are also tracked. For managed languages, namely languages relying
+ * on garbage collection, a free event is generated when an object is
+ * reclaimed by the garbage collector.  These sampled events can be
+ * used to approximate the full history of allocations afterwards.
+ * That means we can get various memory profiles of a program in
+ * different perspectives by post-processing the history in different
+ * ways. The profiler is designed at the very beginning to support not
+ * only JavaScript but also native codes. Naturally, not only
+ * JavaScript objects but also native allocations are tracked.
+ *
+ * The result returned is the sampled allocation event traces in a
+ * compact format. The events is sorted according to the timestamp
+ * when the event happened. Each event has a trace index pointing to
+ * the traces table. Each trace entry has a name index pointing to the
+ * names table and a parent index pointing to the parent trace in the
+ * traces table. By following the trace index one could rebuild the
+ * complete backtrace of an allocation event.
+ *
+ *    [ Events ]
+ *    +-------+-------+      +-------+
+ *    | Size  | Size  |      | Size  |
+ *    |-------|-------|      |-------|
+ *    | Time  | Time  |......| Time  |
+ *    |-------|-------|      |-------|
+ *  +-- Trace | Trace |      | Trace |
+ *  | +-------+-------+      +-------+
+ *  |
+ *  | [ Traces ]
+ *  +->--------+--------+   +--------+   +--------+
+ *   -| Name   | Name   |   | Name   |   | Name   |
+ *  / |--------|--------|...|--------|...|--------|
+ *  | | Parent | Parent |   | Parent |   | Parent |
+ *  | +---|----+----^--++   +--^--|--+   +---^----+
+ *  |     |         |  |       |  |          |
+ *  |     +---------+  +-------+  +----------+
+ *  | [ Names ]
+ *  | +-----------------+-----------------+
+ *  +-> Function name   | Function name   |
+ *    |  & line numbers |  & line numbers |......
+ *    +-----------------+-----------------+
+ *
+ */
+[scriptable, uuid(1e10e7a9-bc05-4878-a687-36c9ea4428b1)]
+interface nsIMemoryProfiler : nsISupports
+{
+  void startProfiler();
+  void stopProfiler();
+  void resetProfiler();
+
+  /**
+   * Get results in an object which contains three tables:
+   * {
+   *  names, // an array of function names and positions
+   *  traces, // an array of {nameIdx, parentIdx}
+   *  events, // an array of {size, timestamp, traceIdx}
+   * }
+   * Should only be called after stopProfiler.
+   */
+  [implicit_jscontext]
+  jsval getResults();
+};
diff --git a/tools/memory-profiler/nsMemoryProfilerFactory.cpp b/tools/memory-profiler/nsMemoryProfilerFactory.cpp
new file mode 100644
index 0000000000..b962a66048
--- /dev/null
+++ b/tools/memory-profiler/nsMemoryProfilerFactory.cpp
@@ -0,0 +1,32 @@
+/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* 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 "mozilla/ModuleUtils.h"
+#include "nsCOMPtr.h"
+#include "MemoryProfiler.h"
+
+using mozilla::MemoryProfiler;
+
+NS_GENERIC_FACTORY_CONSTRUCTOR(MemoryProfiler)
+
+NS_DEFINE_NAMED_CID(MEMORY_PROFILER_CID);
+
+static const mozilla::Module::CIDEntry kMemoryProfilerCIDs[] = {
+  { &kMEMORY_PROFILER_CID, false, nullptr, MemoryProfilerConstructor },
+  { nullptr }
+};
+
+static const mozilla::Module::ContractIDEntry kMemoryProfilerContracts[] = {
+  { MEMORY_PROFILER_CONTRACT_ID, &kMEMORY_PROFILER_CID },
+  { nullptr }
+};
+
+static const mozilla::Module kMemoryProfilerModule = {
+  mozilla::Module::kVersion,
+  kMemoryProfilerCIDs,
+  kMemoryProfilerContracts
+};
+
+NSMODULE_DEFN(nsMemoryProfilerModule) = &kMemoryProfilerModule;