1// weak_undef_file1.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// an arbitrary symbol other than the weak undefined symbol 29// referenced by the main program. The main program will be 30// linked with this library so that the symbol remains undefined. 31// Through the use of the embedded RPATH, the program will load 32// an 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#include <cstdio> 37 38#include "weak_undef.h" 39 40int is_such_symbol_ = 1; 41 42// We also define a symbol that is not defined by the alternate 43// library. The main program contains a weak reference to this 44// symbol, and tests that the reference remains weak even after 45// the definition was found at link time. 46 47int link_time_only = 1; 48 49extern int v2 __attribute__ ((weak)); 50 51int *v3 = &v2; 52 53int 54t1() 55{ 56 return is_such_symbol_; 57} 58 59// Test that a weak reference from a shared library to a symbol 60// defined in the main program does get resolved. 61 62int 63t2() 64{ 65 return (&v2 == NULL) ? -1 : v2; 66} 67 68// Test that a weak reference from a shared library to a symbol 69// defined in the main program does get resolved. 70 71int 72t3() 73{ 74 return (v3 == NULL) ? -1 : *v3; 75} 76