gold/testsuite/weak_undef_file2.cc

   1 // weak_undef_file2.cc -- test handling of weak undefined symbols for gold
   2
   3 // Copyright (C) 2008-2021 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
  41 int is_such_symbol_ = 1;
  42 int no_such_symbol_ = 2;
  43
  44 extern int v2 __attribute__ ((weak));
  45
  46 int *v3 = &v2;
  47
  48 int
  49 t1()
  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
  57 int
  58 t2()
  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
  66 int
  67 t3()
  68 {
  69   return (v3 == NULL) ? -1 : *v3;
  70 }