Add m-esr52 at 52.6.0

5 files changed, 781 insertions, 0 deletions

diff --git a/memory/replace/logalloc/replay/Makefile.in b/memory/replace/logalloc/replay/Makefile.in
new file mode 100644
index 000000000..47e8c43ca
--- /dev/null
+++ b/memory/replace/logalloc/replay/Makefile.in
@@ -0,0 +1,32 @@
+# 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 $(topsrcdir)/mozglue/build/replace_malloc.mk
+
+ifndef CROSS_COMPILE
+
+ifeq ($(OS_TARGET),WINNT)
+LOGALLOC = MOZ_REPLACE_MALLOC_LIB=$(CURDIR)/../logalloc.dll
+else
+ifeq ($(OS_TARGET),Darwin)
+LOGALLOC = DYLD_INSERT_LIBRARIES=$(CURDIR)/../liblogalloc.dylib
+else
+LOGALLOC = LD_PRELOAD=$(CURDIR)/../$(DLL_PREFIX)logalloc$(DLL_SUFFIX)
+endif
+endif
+
+expected_output.log: $(srcdir)/replay.log
+# The logalloc-replay program will only replay entries from the first pid,
+# so the expected output only contains entries beginning with "1 "
+	grep "^1 " $< > $@
+
+check:: $(srcdir)/replay.log expected_output.log
+# Test with MALLOC_LOG as a file descriptor number
+	MALLOC_LOG=1 $(LOGALLOC) ./$(PROGRAM) < $< | $(PYTHON) $(srcdir)/logalloc_munge.py | diff -w - expected_output.log
+# Test with MALLOC_LOG as a file name
+	$(RM) test_output.log
+	MALLOC_LOG=test_output.log $(LOGALLOC) ./$(PROGRAM) < $<
+	$(PYTHON) $(srcdir)/logalloc_munge.py < test_output.log | diff -w - expected_output.log
+
+endif
diff --git a/memory/replace/logalloc/replay/Replay.cpp b/memory/replace/logalloc/replay/Replay.cpp
new file mode 100644
index 000000000..30fcd21e5
--- /dev/null
+++ b/memory/replace/logalloc/replay/Replay.cpp
@@ -0,0 +1,558 @@
+/* -*- 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/. */
+
+#define MOZ_MEMORY_IMPL
+#include "mozmemory_wrap.h"
+
+#ifdef _WIN32
+#include <windows.h>
+#include <io.h>
+typedef int ssize_t;
+#else
+#include <sys/mman.h>
+#include <unistd.h>
+#endif
+#include <algorithm>
+#include <cstdio>
+#include <cstring>
+
+#include "mozilla/Assertions.h"
+#include "FdPrintf.h"
+
+static void
+die(const char* message)
+{
+  /* Here, it doesn't matter that fprintf may allocate memory. */
+  fprintf(stderr, "%s\n", message);
+  exit(1);
+}
+
+/* We don't want to be using malloc() to allocate our internal tracking
+ * data, because that would change the parameters of what is being measured,
+ * so we want to use data types that directly use mmap/VirtualAlloc. */
+template <typename T, size_t Len>
+class MappedArray
+{
+public:
+  MappedArray(): mPtr(nullptr) {}
+
+  ~MappedArray()
+  {
+    if (mPtr) {
+#ifdef _WIN32
+      VirtualFree(mPtr, sizeof(T) * Len, MEM_RELEASE);
+#else
+      munmap(mPtr, sizeof(T) * Len);
+#endif
+    }
+  }
+
+  T& operator[] (size_t aIndex) const
+  {
+    if (mPtr) {
+      return mPtr[aIndex];
+    }
+
+#ifdef _WIN32
+    mPtr = reinterpret_cast<T*>(VirtualAlloc(nullptr, sizeof(T) * Len,
+             MEM_COMMIT | MEM_RESERVE, PAGE_READWRITE));
+    if (mPtr == nullptr) {
+      die("VirtualAlloc error");
+    }
+#else
+    mPtr = reinterpret_cast<T*>(mmap(nullptr, sizeof(T) * Len,
+             PROT_READ | PROT_WRITE, MAP_ANON | MAP_PRIVATE, -1, 0));
+    if (mPtr == MAP_FAILED) {
+      die("Mmap error");
+    }
+#endif
+    return mPtr[aIndex];
+  }
+
+private:
+  mutable T* mPtr;
+};
+
+/* Type for records of allocations. */
+struct MemSlot
+{
+  void* mPtr;
+  size_t mSize;
+};
+
+/* An almost infinite list of slots.
+ * In essence, this is a linked list of arrays of groups of slots.
+ * Each group is 1MB. On 64-bits, one group allows to store 64k allocations.
+ * Each MemSlotList instance can store 1023 such groups, which means more
+ * than 65M allocations. In case more would be needed, we chain to another
+ * MemSlotList, and so on.
+ * Using 1023 groups makes the MemSlotList itself page sized on 32-bits
+ * and 2 pages-sized on 64-bits.
+ */
+class MemSlotList
+{
+  static const size_t kGroups = 1024 - 1;
+  static const size_t kGroupSize = (1024 * 1024) / sizeof(MemSlot);
+
+  MappedArray<MemSlot, kGroupSize> mSlots[kGroups];
+  MappedArray<MemSlotList, 1> mNext;
+
+public:
+  MemSlot& operator[] (size_t aIndex) const
+  {
+    if (aIndex < kGroupSize * kGroups) {
+      return mSlots[aIndex / kGroupSize][aIndex % kGroupSize];
+    }
+    aIndex -= kGroupSize * kGroups;
+    return mNext[0][aIndex];
+  }
+};
+
+/* Helper class for memory buffers */
+class Buffer
+{
+public:
+  Buffer() : mBuf(nullptr), mLength(0) {}
+
+  Buffer(const void* aBuf, size_t aLength)
+    : mBuf(reinterpret_cast<const char*>(aBuf)), mLength(aLength)
+  {}
+
+  /* Constructor for string literals. */
+  template <size_t Size>
+  explicit Buffer(const char (&aStr)[Size])
+    : mBuf(aStr), mLength(Size - 1)
+  {}
+
+  /* Returns a sub-buffer up-to but not including the given aNeedle character.
+   * The "parent" buffer itself is altered to begin after the aNeedle
+   * character.
+   * If the aNeedle character is not found, return the entire buffer, and empty
+   * the "parent" buffer. */
+  Buffer SplitChar(char aNeedle)
+  {
+    char* buf = const_cast<char*>(mBuf);
+    char* c = reinterpret_cast<char*>(memchr(buf, aNeedle, mLength));
+    if (!c) {
+      return Split(mLength);
+    }
+
+    Buffer result = Split(c - buf);
+    // Remove the aNeedle character itself.
+    Split(1);
+    return result;
+  }
+
+  /* Returns a sub-buffer of at most aLength characters. The "parent" buffer is
+   * amputated of those aLength characters. If the "parent" buffer is smaller
+   * than aLength, then its length is used instead. */
+  Buffer Split(size_t aLength)
+  {
+    Buffer result(mBuf, std::min(aLength, mLength));
+    mLength -= result.mLength;
+    mBuf += result.mLength;
+    return result;
+  }
+
+  /* Move the buffer (including its content) to the memory address of the aOther
+   * buffer. */
+  void Slide(Buffer aOther)
+  {
+    memmove(const_cast<char*>(aOther.mBuf), mBuf, mLength);
+    mBuf = aOther.mBuf;
+  }
+
+  /* Returns whether the two involved buffers have the same content. */
+  bool operator ==(Buffer aOther)
+  {
+    return mLength == aOther.mLength && (mBuf == aOther.mBuf ||
+                                         !strncmp(mBuf, aOther.mBuf, mLength));
+  }
+
+  /* Returns whether the buffer is empty. */
+  explicit operator bool() { return mLength; }
+
+  /* Returns the memory location of the buffer. */
+  const char* get() { return mBuf; }
+
+  /* Returns the memory location of the end of the buffer (technically, the
+   * first byte after the buffer). */
+  const char* GetEnd() { return mBuf + mLength; }
+
+  /* Extend the buffer over the content of the other buffer, assuming it is
+   * adjacent. */
+  void Extend(Buffer aOther)
+  {
+    MOZ_ASSERT(aOther.mBuf == GetEnd());
+    mLength += aOther.mLength;
+  }
+
+private:
+  const char* mBuf;
+  size_t mLength;
+};
+
+/* Helper class to read from a file descriptor line by line. */
+class FdReader {
+public:
+  explicit FdReader(int aFd)
+    : mFd(aFd)
+    , mData(&mRawBuf, 0)
+    , mBuf(&mRawBuf, sizeof(mRawBuf))
+  {}
+
+  /* Read a line from the file descriptor and returns it as a Buffer instance */
+  Buffer ReadLine()
+  {
+    while (true) {
+      Buffer result = mData.SplitChar('\n');
+
+      /* There are essentially three different cases here:
+       * - '\n' was found "early". In this case, the end of the result buffer
+       *   is before the beginning of the mData buffer (since SplitChar
+       *   amputated it).
+       * - '\n' was found as the last character of mData. In this case, mData
+       *   is empty, but still points at the end of mBuf. result points to what
+       *   used to be in mData, without the last character.
+       * - '\n' was not found. In this case too, mData is empty and points at
+       *   the end of mBuf. But result points to the entire buffer that used to
+       *   be pointed by mData.
+       * Only in the latter case do both result and mData's end match, and it's
+       * the only case where we need to refill the buffer.
+       */
+      if (result.GetEnd() != mData.GetEnd()) {
+        return result;
+      }
+
+      /* Since SplitChar emptied mData, make it point to what it had before. */
+      mData = result;
+
+      /* And move it to the beginning of the read buffer. */
+      mData.Slide(mBuf);
+
+      FillBuffer();
+
+      if (!mData) {
+        return Buffer();
+      }
+    }
+  }
+
+private:
+  /* Fill the read buffer. */
+  void FillBuffer()
+  {
+    size_t size = mBuf.GetEnd() - mData.GetEnd();
+    Buffer remainder(mData.GetEnd(), size);
+
+    ssize_t len = 1;
+    while (remainder && len > 0) {
+      len = ::read(mFd, const_cast<char*>(remainder.get()), size);
+      if (len < 0) {
+        die("Read error");
+      }
+      size -= len;
+      mData.Extend(remainder.Split(len));
+    }
+  }
+
+  /* File descriptor to read from. */
+  int mFd;
+  /* Part of data that was read from the file descriptor but not returned with
+   * ReadLine yet. */
+  Buffer mData;
+  /* Buffer representation of mRawBuf */
+  Buffer mBuf;
+  /* read() buffer */
+  char mRawBuf[4096];
+};
+
+MOZ_BEGIN_EXTERN_C
+
+/* Function declarations for all the replace_malloc _impl functions.
+ * See memory/build/replace_malloc.c */
+#define MALLOC_DECL(name, return_type, ...) \
+  return_type name ## _impl(__VA_ARGS__);
+#define MALLOC_FUNCS MALLOC_FUNCS_MALLOC
+#include "malloc_decls.h"
+
+#define MALLOC_DECL(name, return_type, ...) \
+  return_type name ## _impl(__VA_ARGS__);
+#define MALLOC_FUNCS MALLOC_FUNCS_JEMALLOC
+#include "malloc_decls.h"
+
+/* mozjemalloc relies on DllMain to initialize, but DllMain is not invoked
+ * for executables, so manually invoke mozjemalloc initialization. */
+#if defined(_WIN32) && !defined(MOZ_JEMALLOC4)
+void malloc_init_hard(void);
+#endif
+
+#ifdef ANDROID
+/* mozjemalloc uses MozTagAnonymousMemory, which doesn't have an inline
+ * implementation on Android */
+void
+MozTagAnonymousMemory(const void* aPtr, size_t aLength, const char* aTag) {}
+
+/* mozjemalloc and jemalloc use pthread_atfork, which Android doesn't have.
+ * While gecko has one in libmozglue, the replay program can't use that.
+ * Since we're not going to fork anyways, make it a dummy function. */
+int
+pthread_atfork(void (*aPrepare)(void), void (*aParent)(void),
+               void (*aChild)(void))
+{
+  return 0;
+}
+#endif
+
+MOZ_END_EXTERN_C
+
+size_t parseNumber(Buffer aBuf)
+{
+  if (!aBuf) {
+    die("Malformed input");
+  }
+
+  size_t result = 0;
+  for (const char* c = aBuf.get(), *end = aBuf.GetEnd(); c < end; c++) {
+    if (*c < '0' || *c > '9') {
+      die("Malformed input");
+    }
+    result *= 10;
+    result += *c - '0';
+  }
+  return result;
+}
+
+/* Class to handle dispatching the replay function calls to replace-malloc. */
+class Replay
+{
+public:
+  Replay(): mOps(0) {
+#ifdef _WIN32
+    // See comment in FdPrintf.h as to why native win32 handles are used.
+    mStdErr = reinterpret_cast<intptr_t>(GetStdHandle(STD_ERROR_HANDLE));
+#else
+    mStdErr = fileno(stderr);
+#endif
+  }
+
+  MemSlot& operator[] (size_t index) const
+  {
+    return mSlots[index];
+  }
+
+  void malloc(MemSlot& aSlot, Buffer& aArgs)
+  {
+    mOps++;
+    size_t size = parseNumber(aArgs);
+    aSlot.mPtr = ::malloc_impl(size);
+    aSlot.mSize = size;
+    Commit(aSlot);
+  }
+
+  void posix_memalign(MemSlot& aSlot, Buffer& aArgs)
+  {
+    mOps++;
+    size_t alignment = parseNumber(aArgs.SplitChar(','));
+    size_t size = parseNumber(aArgs);
+    void* ptr;
+    if (::posix_memalign_impl(&ptr, alignment, size) == 0) {
+      aSlot.mPtr = ptr;
+      aSlot.mSize = size;
+    } else {
+      aSlot.mPtr = nullptr;
+      aSlot.mSize = 0;
+    }
+    Commit(aSlot);
+  }
+
+  void aligned_alloc(MemSlot& aSlot, Buffer& aArgs)
+  {
+    mOps++;
+    size_t alignment = parseNumber(aArgs.SplitChar(','));
+    size_t size = parseNumber(aArgs);
+    aSlot.mPtr = ::aligned_alloc_impl(alignment, size);
+    aSlot.mSize = size;
+    Commit(aSlot);
+  }
+
+  void calloc(MemSlot& aSlot, Buffer& aArgs)
+  {
+    mOps++;
+    size_t num = parseNumber(aArgs.SplitChar(','));
+    size_t size = parseNumber(aArgs);
+    aSlot.mPtr = ::calloc_impl(num, size);
+    aSlot.mSize = size * num;
+    Commit(aSlot);
+  }
+
+  void realloc(MemSlot& aSlot, Buffer& aArgs)
+  {
+    mOps++;
+    Buffer dummy = aArgs.SplitChar('#');
+    if (dummy) {
+      die("Malformed input");
+    }
+    size_t slot_id = parseNumber(aArgs.SplitChar(','));
+    size_t size = parseNumber(aArgs);
+    MemSlot& old_slot = (*this)[slot_id];
+    void* old_ptr = old_slot.mPtr;
+    old_slot.mPtr = nullptr;
+    old_slot.mSize = 0;
+    aSlot.mPtr = ::realloc_impl(old_ptr, size);
+    aSlot.mSize = size;
+    Commit(aSlot);
+  }
+
+  void free(Buffer& aArgs)
+  {
+    mOps++;
+    Buffer dummy = aArgs.SplitChar('#');
+    if (dummy) {
+      die("Malformed input");
+    }
+    size_t slot_id = parseNumber(aArgs);
+    MemSlot& slot = (*this)[slot_id];
+    ::free_impl(slot.mPtr);
+    slot.mPtr = nullptr;
+    slot.mSize = 0;
+  }
+
+  void memalign(MemSlot& aSlot, Buffer& aArgs)
+  {
+    mOps++;
+    size_t alignment = parseNumber(aArgs.SplitChar(','));
+    size_t size = parseNumber(aArgs);
+    aSlot.mPtr = ::memalign_impl(alignment, size);
+    aSlot.mSize = size;
+    Commit(aSlot);
+  }
+
+  void valloc(MemSlot& aSlot, Buffer& aArgs)
+  {
+    mOps++;
+    size_t size = parseNumber(aArgs);
+    aSlot.mPtr = ::valloc_impl(size);
+    aSlot.mSize = size;
+    Commit(aSlot);
+  }
+
+  void jemalloc_stats(Buffer& aArgs)
+  {
+    if (aArgs) {
+      die("Malformed input");
+    }
+    jemalloc_stats_t stats;
+    ::jemalloc_stats_impl(&stats);
+    FdPrintf(mStdErr,
+             "#%zu mapped: %zu; allocated: %zu; waste: %zu; dirty: %zu; "
+             "bookkeep: %zu; binunused: %zu\n", mOps, stats.mapped,
+             stats.allocated, stats.waste, stats.page_cache,
+             stats.bookkeeping, stats.bin_unused);
+    /* TODO: Add more data, like actual RSS as measured by OS, but compensated
+     * for the replay internal data. */
+  }
+
+private:
+  void Commit(MemSlot& aSlot)
+  {
+    memset(aSlot.mPtr, 0x5a, aSlot.mSize);
+  }
+
+  intptr_t mStdErr;
+  size_t mOps;
+  MemSlotList mSlots;
+};
+
+
+int
+main()
+{
+  size_t first_pid = 0;
+  FdReader reader(0);
+  Replay replay;
+
+#if defined(_WIN32) && !defined(MOZ_JEMALLOC4)
+  malloc_init_hard();
+#endif
+
+  /* Read log from stdin and dispatch function calls to the Replay instance.
+   * The log format is essentially:
+   *   <pid> <function>([<args>])[=<result>]
+   * <args> is a comma separated list of arguments.
+   *
+   * The logs are expected to be preprocessed so that allocations are
+   * attributed a tracking slot. The input is trusted not to have crazy
+   * values for these slot numbers.
+   *
+   * <result>, as well as some of the args to some of the function calls are
+   * such slot numbers.
+   */
+  while (true) {
+    Buffer line = reader.ReadLine();
+
+    if (!line) {
+      break;
+    }
+
+    size_t pid = parseNumber(line.SplitChar(' '));
+    if (!first_pid) {
+      first_pid = pid;
+    }
+
+    /* The log may contain data for several processes, only entries for the
+     * very first that appears are treated. */
+    if (first_pid != pid) {
+      continue;
+    }
+
+    /* The log contains thread ids for manual analysis, but we just ignore them
+     * for now. */
+    parseNumber(line.SplitChar(' '));
+
+    Buffer func = line.SplitChar('(');
+    Buffer args = line.SplitChar(')');
+
+    /* jemalloc_stats and free are functions with no result. */
+    if (func == Buffer("jemalloc_stats")) {
+      replay.jemalloc_stats(args);
+      continue;
+    } else if (func == Buffer("free")) {
+      replay.free(args);
+      continue;
+    }
+
+    /* Parse result value and get the corresponding slot. */
+    Buffer dummy = line.SplitChar('=');
+    Buffer dummy2 = line.SplitChar('#');
+    if (dummy || dummy2) {
+      die("Malformed input");
+    }
+
+    size_t slot_id = parseNumber(line);
+    MemSlot& slot = replay[slot_id];
+
+    if (func == Buffer("malloc")) {
+      replay.malloc(slot, args);
+    } else if (func == Buffer("posix_memalign")) {
+      replay.posix_memalign(slot, args);
+    } else if (func == Buffer("aligned_alloc")) {
+      replay.aligned_alloc(slot, args);
+    } else if (func == Buffer("calloc")) {
+      replay.calloc(slot, args);
+    } else if (func == Buffer("realloc")) {
+      replay.realloc(slot, args);
+    } else if (func == Buffer("memalign")) {
+      replay.memalign(slot, args);
+    } else if (func == Buffer("valloc")) {
+      replay.valloc(slot, args);
+    } else {
+      die("Malformed input");
+    }
+  }
+
+  return 0;
+}
diff --git a/memory/replace/logalloc/replay/logalloc_munge.py b/memory/replace/logalloc/replay/logalloc_munge.py
new file mode 100644
index 000000000..a244c3c3d
--- /dev/null
+++ b/memory/replace/logalloc/replay/logalloc_munge.py
@@ -0,0 +1,147 @@
+# 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/.
+
+"""
+This script takes a log from the replace-malloc logalloc library on stdin
+and munges it so that it can be used with the logalloc-replay tool.
+
+Given the following output:
+  13663 malloc(42)=0x7f0c33502040
+  13663 malloc(24)=0x7f0c33503040
+  13663 free(0x7f0c33502040)
+The resulting output is:
+  1 malloc(42)=#1
+  1 malloc(24)=#2
+  1 free(#1)
+
+See README for more details.
+"""
+
+from __future__ import print_function
+import sys
+from collections import (
+    defaultdict,
+    deque,
+)
+
+class IdMapping(object):
+    """Class to map values to ids.
+
+    Each value is associated to an increasing id, starting from 1.
+    When a value is removed, its id is recycled and will be reused for
+    subsequent values.
+    """
+    def __init__(self):
+        self.id = 1
+        self._values = {}
+        self._recycle = deque()
+
+    def __getitem__(self, value):
+        if value not in self._values:
+            if self._recycle:
+                self._values[value] = self._recycle.popleft()
+            else:
+                self._values[value] = self.id
+                self.id += 1
+        return self._values[value]
+
+    def __delitem__(self, value):
+        if value == 0:
+            return
+        self._recycle.append(self._values[value])
+        del self._values[value]
+
+    def __contains__(self, value):
+        return value == 0 or value in self._values
+
+
+class Ignored(Exception): pass
+
+
+def split_log_line(line):
+    try:
+        # The format for each line is:
+        # <pid> [<tid>] <function>([<args>])[=<result>]
+        #
+        # The original format didn't include the tid, so we try to parse
+        # lines whether they have one or not.
+        pid, func_call = line.split(' ', 1)
+        call, result = func_call.split(')')
+        func, args = call.split('(')
+        args = args.split(',') if args else []
+        if result:
+            if result[0] != '=':
+                raise Ignored('Malformed input')
+            result = result[1:]
+        if ' ' in func:
+            tid, func = func.split(' ', 1)
+        else:
+            tid = pid
+        return pid, tid, func, args, result
+    except:
+        raise Ignored('Malformed input')
+
+
+NUM_ARGUMENTS = {
+    'jemalloc_stats': 0,
+    'free': 1,
+    'malloc': 1,
+    'posix_memalign': 2,
+    'aligned_alloc': 2,
+    'calloc': 2,
+    'realloc': 2,
+    'memalign': 2,
+    'valloc': 1,
+}
+
+
+def main():
+    pids = IdMapping()
+    processes = defaultdict(lambda: { 'pointers': IdMapping(),
+                                      'tids': IdMapping() })
+    for line in sys.stdin:
+        line = line.strip()
+
+        try:
+            pid, tid, func, args, result = split_log_line(line)
+
+            # Replace pid with an id.
+            pid = pids[int(pid)]
+
+            process = processes[pid]
+            tid = process['tids'][int(tid)]
+
+            pointers = process['pointers']
+
+            if func not in NUM_ARGUMENTS:
+                raise Ignored('Unknown function')
+
+            if len(args) != NUM_ARGUMENTS[func]:
+                raise Ignored('Malformed input')
+
+            if func in ('jemalloc_stats', 'free') and result:
+                raise Ignored('Malformed input')
+
+            if func in ('free', 'realloc'):
+                ptr = int(args[0], 16)
+                if ptr and ptr not in pointers:
+                    raise Ignored('Did not see an alloc for pointer')
+                args[0] = "#%d" % pointers[ptr]
+                del pointers[ptr]
+
+            if result:
+                result = int(result, 16)
+                if not result:
+                    raise Ignored('Result is NULL')
+                result = "#%d" % pointers[result]
+
+            print('%d %d %s(%s)%s' % (pid, tid, func, ','.join(args),
+                '=%s' % result if result else ''))
+
+        except Exception as e:
+            print('Ignored "%s": %s' % (line, e.message), file=sys.stderr)
+
+
+if __name__ == '__main__':
+    main()
diff --git a/memory/replace/logalloc/replay/moz.build b/memory/replace/logalloc/replay/moz.build
new file mode 100644
index 000000000..bb976908f
--- /dev/null
+++ b/memory/replace/logalloc/replay/moz.build
@@ -0,0 +1,27 @@
+# -*- 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/.
+
+Program('logalloc-replay')
+
+SOURCES += [
+    '../FdPrintf.cpp',
+    '/mfbt/Assertions.cpp',
+    'Replay.cpp',
+]
+
+LOCAL_INCLUDES += [
+    '..',
+]
+
+# Link replace-malloc and the default allocator.
+USE_LIBS += [
+    'memory',
+]
+
+# The memory library defines this, so it's needed here too.
+DEFINES['IMPL_MFBT'] = True
+
+DISABLE_STL_WRAPPING = True
diff --git a/memory/replace/logalloc/replay/replay.log b/memory/replace/logalloc/replay/replay.log
new file mode 100644
index 000000000..c56dfab12
--- /dev/null
+++ b/memory/replace/logalloc/replay/replay.log
@@ -0,0 +1,17 @@
+1 1 malloc(42)=#1
+1 1 malloc(24)=#2
+2 2 malloc(42)=#1
+1 1 free(#1)
+1 1 posix_memalign(4096,1024)=#1
+1 1 calloc(4,42)=#3
+1 1 free(#2)
+1 1 realloc(#3,84)=#2
+1 1 aligned_alloc(512,1024)=#3
+1 1 memalign(512,1024)=#4
+1 1 valloc(1024)=#5
+1 1 jemalloc_stats()
+1 1 free(#5)
+1 1 free(#4)
+1 1 free(#3)
+1 1 free(#2)
+1 1 free(#1)