1 // Copyright 2024 The PDFium Authors 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 CORE_FXCRT_DEBUG_ALIAS_H_ 6 #define CORE_FXCRT_DEBUG_ALIAS_H_ 7 8 namespace pdfium { 9 10 // Make the optimizer think that var is aliased. This is to prevent it from 11 // optimizing out local variables that would not otherwise be live at the point 12 // of a potential crash. 13 // pdfium::Alias should only be used for local variables, not globals, 14 // object members, or function return values - these must be copied to locals if 15 // you want to ensure they are recorded in crash dumps. 16 // Note that if the local variable is a pointer then its value will be retained 17 // but the memory that it points to will probably not be saved in the crash 18 // dump - by default only stack memory is saved. Therefore the aliasing 19 // technique is usually only worthwhile with non-pointer variables. If you have 20 // a pointer to an object and you want to retain the object's state you need to 21 // copy the object or its fields to local variables. Example usage: 22 // int last_error = err_; 23 // pdfium::Alias(&last_error); 24 // DEBUG_ALIAS_FOR_CSTR(name_copy, p->name, 16); 25 // CHECK(false); 26 void Alias(const void* var); 27 28 } // namespace pdfium 29 30 #endif // CORE_FXCRT_DEBUG_ALIAS_H_ 31