gold/testsuite/weak_undef_file1.cc

   1 // weak_undef_file1.cc -- test handling of weak undefined symbols for gold
   2
   3 // Copyright (C) 2008-2015 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
  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 }