1// weak_undef_file2.cc -- test handling of weak undefined symbols for gold 2 3// Copyright (C) 2008-2020 Free Software Foundation, Inc. 4// Written by Cary Coutant <ccoutant@google.com>. 5 6// This file is part of gold. 7 8// This program is free software; you can redistribute it and/or modify 9// it under the terms of the GNU General Public License as published by 10// the Free Software Foundation; either version 3 of the License, or 11// (at your option) any later version. 12 13// This program is distributed in the hope that it will be useful, 14// but WITHOUT ANY WARRANTY; without even the implied warranty of 15// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16// GNU General Public License for more details. 17 18// You should have received a copy of the GNU General Public License 19// along with this program; if not, write to the Free Software 20// Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, 21// MA 02110-1301, USA. 22 23// We test that we correctly deal with weak undefined symbols. 24// We need to make sure that the symbol is resolved to zero 25// by the linker and that no dynamic relocation is generated. 26 27// This source is used to build a shared library that defines 28// the weak undefined symbol referenced by the main program. 29// The main program will be linked with a library that does not 30// provide this definition, so that the symbol remains undefined. 31// Through the use of the embedded RPATH, the program will load 32// this alternate shared library that does define the symbol, 33// so that we can detect whether the symbol was left for runtime 34// resolution. 35 36 37#include <cstdio> 38 39#include "weak_undef.h" 40 41int is_such_symbol_ = 1; 42int no_such_symbol_ = 2; 43 44extern int v2 __attribute__ ((weak)); 45 46int *v3 = &v2; 47 48int 49t1() 50{ 51 return no_such_symbol_; 52} 53 54// Test that a weak reference from a shared library to a symbol 55// defined in the main program does get resolved. 56 57int 58t2() 59{ 60 return (&v2 == NULL) ? -1 : v2; 61} 62 63// Test that a weak reference from a shared library to a symbol 64// defined in the main program does get resolved. 65 66int 67t3() 68{ 69 return (v3 == NULL) ? -1 : *v3; 70} 71