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 "js/ProfilingStack.h" 8 9 #include "mozilla/IntegerRange.h" 10 #include "mozilla/MathAlgorithms.h" 11 #include "mozilla/UniquePtr.h" 12 #include "mozilla/UniquePtrExtensions.h" 13 14 #include <algorithm> 15 16 using namespace js; 17 ~ProfilingStack()18ProfilingStack::~ProfilingStack() { 19 // The label macros keep a reference to the ProfilingStack to avoid a TLS 20 // access. If these are somehow not all cleared we will get a 21 // use-after-free so better to crash now. 22 MOZ_RELEASE_ASSERT(stackPointer == 0); 23 24 delete[] frames; 25 } 26 ensureCapacitySlow()27void ProfilingStack::ensureCapacitySlow() { 28 MOZ_ASSERT(stackPointer >= capacity); 29 const uint32_t kInitialCapacity = 4096 / sizeof(ProfilingStackFrame); 30 31 uint32_t sp = stackPointer; 32 33 uint32_t newCapacity; 34 if (!capacity) { 35 newCapacity = kInitialCapacity; 36 } else { 37 size_t memoryGoal = 38 mozilla::RoundUpPow2(capacity * 2 * sizeof(ProfilingStackFrame)); 39 newCapacity = memoryGoal / sizeof(ProfilingStackFrame); 40 } 41 newCapacity = std::max(sp + 1, newCapacity); 42 43 auto* newFrames = new js::ProfilingStackFrame[newCapacity]; 44 45 // It's important that `frames` / `capacity` / `stackPointer` remain 46 // consistent here at all times. 47 for (auto i : mozilla::IntegerRange(capacity)) { 48 newFrames[i] = frames[i]; 49 } 50 51 js::ProfilingStackFrame* oldFrames = frames; 52 frames = newFrames; 53 capacity = newCapacity; 54 delete[] oldFrames; 55 } 56