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      1 // weak_undef_test.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 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 
     47 extern int no_such_symbol_ __attribute__ ((weak));
     48 
     49 extern int link_time_only __attribute__ ((weak));
     50 
     51 int *p1 = &no_such_symbol_;
     52 
     53 int *p2 = &link_time_only;
     54 
     55 int v2 = 42;
     56 
     57 int
     58 main()
     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