hidePointer.cpp (955B)
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 */ 4 /* This Source Code Form is subject to the terms of the Mozilla Public 5 * License, v. 2.0. If a copy of the MPL was not distributed with this 6 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ 7 8 #include "mozilla/Atomics.h" 9 10 // This is an attempt to hide pointer values from the C++ compiler. This might 11 // not stand up in the presence of PGO but that's probably not important. 12 13 // g_hidden_pointer is public so that it's limited what the compiler can assume 14 // about it, and atomic so that we don't run afoul of the compiler's UB 15 // analysis. 16 17 mozilla::Atomic<void*> g_hidden_pointer; 18 19 // Call this to install a pointer into the global. 20 21 MOZ_NEVER_INLINE void setHiddenPointer(void* p) { g_hidden_pointer = p; } 22 23 // Call this to retrieve the pointer. 24 25 MOZ_NEVER_INLINE void* getHiddenPointer() { return g_hidden_pointer; }