mozglue/baseprofiler/core/ProfilingStack.cpp

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
   2  * vim: set ts=8 sts=2 et sw=2 tw=80:
   3  * This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "BaseProfilingStack.h"
   8
   9 #include <algorithm>
  10
  11 #include "mozilla/IntegerRange.h"
  12 #include "mozilla/UniquePtr.h"
  13 #include "mozilla/UniquePtrExtensions.h"
  14
  15 #include "BaseProfiler.h"
  16
  17 namespace mozilla {
  18 namespace baseprofiler {
  19
  20 ProfilingStack::~ProfilingStack() {
  21   // The label macros keep a reference to the ProfilingStack to avoid a TLS
  22   // access. If these are somehow not all cleared we will get a
  23   // use-after-free so better to crash now.
  24   MOZ_RELEASE_ASSERT(stackPointer == 0);
  25
  26   delete[] frames;
  27 }
  28
  29 void ProfilingStack::ensureCapacitySlow() {
  30   MOZ_ASSERT(stackPointer >= capacity);
  31   const uint32_t kInitialCapacity = 128;
  32
  33   uint32_t sp = stackPointer;
  34   auto newCapacity =
  35       std::max(sp + 1, capacity ? capacity * 2 : kInitialCapacity);
  36
  37   auto* newFrames = new ProfilingStackFrame[newCapacity];
  38
  39   // It's important that `frames` / `capacity` / `stackPointer` remain
  40   // consistent here at all times.
  41   for (auto i : IntegerRange(capacity)) {
  42     newFrames[i] = frames[i];
  43   }
  44
  45   ProfilingStackFrame* oldFrames = frames;
  46   frames = newFrames;
  47   capacity = newCapacity;
  48   delete[] oldFrames;
  49 }
  50
  51 }  // namespace baseprofiler
  52 }  // namespace mozilla