1 // weak_undef_file1.cc -- test handling of weak undefined symbols for gold 2 3 // Copyright (C) 2008-2016 Free Software Foundation, Inc. 4 // Written by Cary Coutant <ccoutant (at) 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 40 int 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 47 int link_time_only = 1; 48 49 extern int v2 __attribute__ ((weak)); 50 51 int *v3 = &v2; 52 53 int 54 t1() 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 62 int 63 t2() 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 71 int 72 t3() 73 { 74 return (v3 == NULL) ? -1 : *v3; 75 } 76
