gcc/config/mips/irix6-libc-compat.c

   1 /* Compensate for inconsistent structure passing conventions on IRIX 6.  */
   2 /* Compile this one with gcc.  */
   3 /* Copyright (C) 2001  Free Software Foundation, Inc.
   4
   5 This file is part of GNU CC.
   6
   7 GNU CC is free software; you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License as published by
   9 the Free Software Foundation; either version 2, or (at your option)
  10 any later version.
  11
  12 In addition to the permissions in the GNU General Public License, the
  13 Free Software Foundation gives you unlimited permission to link the
  14 compiled version of this file into combinations with other programs,
  15 and to distribute those combinations without any restriction coming
  16 from the use of this file.  (The General Public License restrictions
  17 do apply in other respects; for example, they cover modification of
  18 the file, and distribution when not linked into a combine
  19 executable.)
  20
  21 GNU CC is distributed in the hope that it will be useful,
  22 but WITHOUT ANY WARRANTY; without even the implied warranty of
  23 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  24 GNU General Public License for more details.
  25
  26 You should have received a copy of the GNU General Public License
  27 along with GNU CC; see the file COPYING.  If not, write to
  28 the Free Software Foundation, 59 Temple Place - Suite 330,
  29 Boston, MA 02111-1307, USA.  */
  30
  31 /* GCC doesn't correctly implement the structure and union passing and return
  32    conventions of the N32 and N64 ABIs on IRIX 6, as described in the
  33    MIPSpro N32 ABI Handbook, ch. 2, Calling Convention Implementations, p.7.
  34    The ABI requires that structures (or trailing parts of structures) smaller
  35    than 8 bytes (a 64-bit register) are left-justified, whereas GCC
  36    right-justifies them.
  37
  38    While GCC is internally consistent, calling routines compiled with a
  39    compiler that does implement the documented ABI (like SGIs MIPSpro C
  40    compiler) doesn't work.  This is primarily an issue for system libraries
  41    like libc.  Fortunately, there exist only very few routines that take
  42    structure value arguments or return structures by value, so until the
  43    underlying bug is fixed, it is possible to work around it by providing
  44    wrapper functions for the few affected routines that compensate for the
  45    inconsistent alignment.
  46
  47    These wrappers rely on the fact that e.g. libc contains weak versions of
  48    those routines, and the real implementation is provided by _-prefixed
  49    variants.  So we can provide our own versions, which will only be linked
  50    if the application uses any of the affected functions, calling the private
  51    variants after shifting the arguments or results as required.
  52
  53    This is a rewrite of code created by Andy Polyakov.  */
  54
  55 #include "config.h"
  56 #include "system.h"
  57
  58 /* This must only be used for the N32 and N64 ABIs.  O32 is correct.  */
  59
  60 #if _MIPS_SIM == _ABIN32 || _MIPS_SIM == _ABI64
  61
  62 /* The affected arguments need to be shifted by
  63
  64         BITS_PER_WORD - (sizeof (arg) * BITS_PER_UNIT).
  65
  66    Since only 32-bit args and results are involved, the shift count is
  67    always 32.  */
  68 #define SHIFT_BITS      32
  69
  70 extern machreg_t inet_ntoa      PARAMS ((machreg_t));
  71 extern machreg_t inet_lnaof     PARAMS ((machreg_t));
  72 extern machreg_t inet_netof     PARAMS ((machreg_t));
  73 extern machreg_t inet_makeaddr  PARAMS ((machreg_t, machreg_t));
  74
  75 extern machreg_t _inet_ntoa     PARAMS ((machreg_t));
  76 extern machreg_t _inet_lnaof    PARAMS ((machreg_t));
  77 extern machreg_t _inet_netof    PARAMS ((machreg_t));
  78 extern machreg_t _inet_makeaddr PARAMS ((machreg_t, machreg_t));
  79
  80 /* <arpa/inet.h> has
  81
  82         char *inet_ntoa (struct in_addr);
  83
  84    on both IRIX 6.2 and 6.5, with struct in_addr containing a 32-bit int.  */
  85
  86 machreg_t
  87 inet_ntoa (machreg_t in)
  88 {
  89   return _inet_ntoa (in << SHIFT_BITS);
  90 }
  91
  92 /* <arpa/inet.h> has
  93
  94         unsigned long inet_lnaof (struct in_addr);              (IRIX 6.2)
  95         in_addr_t inet_lnaof (struct in_addr);                  (IRIX 6.5)
  96
  97    in_addr_t is a 32-bit int.  */
  98
  99 machreg_t
 100 inet_lnaof (machreg_t in)
 101 {
 102   return _inet_lnaof (in << SHIFT_BITS);
 103 }
 104
 105 /* <arpa/inet.h> has
 106
 107         unsigned long inet_netof (struct in_addr);              (IRIX 6.2)
 108         in_addr_t inet_netof (struct in_addr);                  (IRIX 6.5)  */
 109
 110 machreg_t
 111 inet_netof (machreg_t in)
 112 {
 113   return _inet_netof (in << SHIFT_BITS);
 114 }
 115
 116 /* <arpa/inet.h> has
 117
 118         struct in_addr inet_makeaddr (int, int);                (IRIX 6.2)
 119         struct in_addr inet_makeaddr (in_addr_t, in_addr_t);    (IRIX 6.5)  */
 120
 121 machreg_t
 122 inet_makeaddr (machreg_t net, machreg_t lna)
 123 {
 124   return _inet_makeaddr (net, lna) >> SHIFT_BITS;
 125 }
 126
 127 #if _MIPS_SIM == _ABIN32
 128 extern machreg_t semctl         PARAMS ((machreg_t, machreg_t, machreg_t, machreg_t));
 129 extern machreg_t _semctl        PARAMS ((machreg_t, machreg_t, machreg_t, machreg_t));
 130
 131 /* <sys/sem.h> has
 132
 133         int semctl (int, int, int, ...);
 134
 135    where the variadic argument is union semun if used.  union semun contains
 136    an int and two pointers, so the union is already 64 bits wide under the
 137    N64 ABI and alignment is not an issue.  */
 138
 139 machreg_t
 140 semctl (machreg_t semid, machreg_t semnum, machreg_t cmd, machreg_t arg)
 141 {
 142   return _semctl(semid, semnum, cmd, arg << SHIFT_BITS);
 143 }
 144 #endif /* _ABIN32 */
 145
 146 #endif /* _ABIN32 || _ABI64 */