1 // Copyright (c) 2011 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef THIRD_PARTY_BASE_DEBUG_ALIAS_H_ 6 #define THIRD_PARTY_BASE_DEBUG_ALIAS_H_ 7 8 namespace pdfium { 9 namespace base { 10 namespace debug { 11 12 // Make the optimizer think that var is aliased. This is to prevent it from 13 // optimizing out local variables that would not otherwise be live at the point 14 // of a potential crash. 15 // base::debug::Alias should only be used for local variables, not globals, 16 // object members, or function return values - these must be copied to locals if 17 // you want to ensure they are recorded in crash dumps. 18 // Note that if the local variable is a pointer then its value will be retained 19 // but the memory that it points to will probably not be saved in the crash 20 // dump - by default only stack memory is saved. Therefore the aliasing 21 // technique is usually only worthwhile with non-pointer variables. If you have 22 // a pointer to an object and you want to retain the object's state you need to 23 // copy the object or its fields to local variables. Example usage: 24 // int last_error = err_; 25 // base::debug::Alias(&last_error); 26 // DEBUG_ALIAS_FOR_CSTR(name_copy, p->name, 16); 27 // CHECK(false); 28 void Alias(const void* var); 29 30 } // namespace debug 31 } // namespace base 32 } // namespace pdfium 33 34 #endif // THIRD_PARTY_BASE_DEBUG_ALIAS_H_ 35