1// weak_undef_test.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 a weak undefined symbol in the main 25// program is resolved to zero by the linker and that no dynamic 26// relocation is generated. We also make sure that a weak undefined 27// symbol in a shared library can resolve to a symbol in the main 28// program. 29 30// This file will be linked with a shared library that does not 31// define the symbol, so that the symbol remains undefined. 32// Through the use of LD_LIBRARY_PATH, the program will load 33// an alternate shared library that does define the symbol, 34// so that we can detect whether the symbol was left for runtime 35// resolution. 36 37// Similarly, this file will be linked with a shared library that 38// does define a different symbol, and loaded with an alternate 39// shared library that does not define that symbol. We check that 40// the weak reference remains weak, and that it is resolved to 41// zero at runtime. 42 43 44#include <cstdio> 45#include "weak_undef.h" 46 47extern int no_such_symbol_ __attribute__ ((weak)); 48 49extern int link_time_only __attribute__ ((weak)); 50 51int *p1 = &no_such_symbol_; 52 53int *p2 = &link_time_only; 54 55int v2 = 42; 56 57int 58main() 59{ 60 int status = 0; 61 int v; 62 63 if ((v = t1()) != 2) 64 { 65 fprintf(stderr, "FAILED weak undef test 1: %s\n", 66 "bound to wrong library"); 67 status = 1; 68 } 69 70 if ((v = t2()) != 42) 71 { 72 fprintf(stderr, "FAILED weak undef test 2: expected %d, got %d\n", 73 42, v); 74 status = 1; 75 } 76 77 if ((v = t3()) != 42) 78 { 79 fprintf(stderr, "FAILED weak undef test 3: expected %d, got %d\n", 80 42, v); 81 status = 1; 82 } 83 84 if (&no_such_symbol_ != NULL) 85 { 86 fprintf(stderr, "FAILED weak undef test 4: %s\n", 87 "&no_such_symbol_ is not NULL"); 88 status = 1; 89 } 90 91 if (p1 != NULL) 92 { 93 fprintf(stderr, "FAILED weak undef test 5: %s\n", 94 "p1 is not NULL"); 95 status = 1; 96 } 97 98 if (p2 != NULL) 99 { 100 fprintf(stderr, "FAILED weak undef test 6: %s\n", 101 "p2 is not NULL"); 102 status = 1; 103 } 104 105 return status; 106} 107