ProfilingStack.cpp (1613B)
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 12 #include <algorithm> 13 14 using namespace js; 15 16 ProfilingStack::~ProfilingStack() { 17 // The label macros keep a reference to the ProfilingStack to avoid a TLS 18 // access. If these are somehow not all cleared we will get a 19 // use-after-free so better to crash now. 20 MOZ_RELEASE_ASSERT(stackPointer == 0); 21 22 delete[] frames; 23 } 24 25 void ProfilingStack::ensureCapacitySlow() { 26 MOZ_ASSERT(stackPointer >= capacity); 27 const uint32_t kInitialCapacity = 4096 / sizeof(ProfilingStackFrame); 28 29 uint32_t sp = stackPointer; 30 31 uint32_t newCapacity; 32 if (!capacity) { 33 newCapacity = kInitialCapacity; 34 } else { 35 size_t memoryGoal = 36 mozilla::RoundUpPow2(capacity * 2 * sizeof(ProfilingStackFrame)); 37 newCapacity = memoryGoal / sizeof(ProfilingStackFrame); 38 } 39 newCapacity = std::max(sp + 1, newCapacity); 40 41 auto* newFrames = new js::ProfilingStackFrame[newCapacity]; 42 43 // It's important that `frames` / `capacity` / `stackPointer` remain 44 // consistent here at all times. 45 for (auto i : mozilla::IntegerRange(capacity)) { 46 newFrames[i] = frames[i]; 47 } 48 49 js::ProfilingStackFrame* oldFrames = frames; 50 frames = newFrames; 51 capacity = newCapacity; 52 delete[] oldFrames; 53 }