gas/config/obj-bout.h

   1 /* b.out object file format
   2    Copyright 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1998, 2000,
   3    2002, 2003, 2005 Free Software Foundation, Inc.
   4
   5    This file is part of GAS, the GNU Assembler.
   6
   7    GAS is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as
   9    published by the Free Software Foundation; either version 2,
  10    or (at your option) any later version.
  11
  12    GAS is distributed in the hope that it will be useful, but
  13    WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
  15    the GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public
  18    License along with GAS; see the file COPYING.  If not, write
  19    to the Free Software Foundation, 59 Temple Place - Suite 330, Cambridge, MA
  20    02139, USA.  */
  21
  22 /*
  23  * This file is a modified version of 'a.out.h'.  It is to be used in all GNU
  24  * tools modified to support the i80960 b.out format (or tools that operate on
  25  * object files created by such tools).
  26  *
  27  * All i80960 development is done in a CROSS-DEVELOPMENT environment.  I.e.,
  28  * object code is generated on, and executed under the direction of a symbolic
  29  * debugger running on, a host system.  We do not want to be subject to the
  30  * vagaries of which host it is or whether it supports COFF or a.out format, or
  31  * anything else.  We DO want to:
  32  *
  33  *      o always generate the same format object files, regardless of host.
  34  *
  35  *      o have an 'a.out' header that we can modify for our own purposes
  36  *        (the 80960 is typically an embedded processor and may require
  37  *        enhanced linker support that the normal a.out.h header can't
  38  *        accommodate).
  39  *
  40  * As for byte-ordering, the following rules apply:
  41  *
  42  *      o Text and data that is actually downloaded to the target is always
  43  *        in i80960 (little-endian) order.
  44  *
  45  *      o All other numbers (in the header, symbols, relocation directives)
  46  *        are in host byte-order:  object files CANNOT be lifted from a
  47  *        little-end host and used on a big-endian (or vice versa) without
  48  *        modification.
  49  * ==> THIS IS NO LONGER TRUE USING BFD.  WE CAN GENERATE ANY BYTE ORDER
  50  *     FOR THE HEADER, AND READ ANY BYTE ORDER.  PREFERENCE WOULD BE TO
  51  *     USE LITTLE-ENDIAN BYTE ORDER THROUGHOUT, REGARDLESS OF HOST.  <==
  52  *
  53  *      o The downloader ('comm960') takes care to generate a pseudo-header
  54  *        with correct (i80960) byte-ordering before shipping text and data
  55  *        off to the NINDY monitor in the target systems.  Symbols and
  56  *        relocation info are never sent to the target.
  57  */
  58
  59 #define OBJ_BOUT 1
  60
  61 #define OUTPUT_FLAVOR bfd_target_aout_flavour
  62
  63 #include "targ-cpu.h"
  64
  65 #define OBJ_DEFAULT_OUTPUT_FILE_NAME    "b.out"
  66
  67 extern const short seg_N_TYPE[];
  68 extern const segT N_TYPE_seg[];
  69
  70 #define BMAGIC  0415
  71 /* We don't accept the following (see N_BADMAG macro).
  72  * They're just here so GNU code will compile.
  73  */
  74 #define OMAGIC  0407            /* old impure format */
  75 #define NMAGIC  0410            /* read-only text */
  76 #define ZMAGIC  0413            /* demand load format */
  77
  78 #ifndef DEFAULT_MAGIC_NUMBER_FOR_OBJECT_FILE
  79 #define DEFAULT_MAGIC_NUMBER_FOR_OBJECT_FILE    (BMAGIC)
  80 #endif /* DEFAULT_MAGIC_NUMBER_FOR_OBJECT_FILE */
  81
  82 /* FILE HEADER
  83  *      All 'lengths' are given as a number of bytes.
  84  *      All 'alignments' are for relinkable files only;  an alignment of
  85  *              'n' indicates the corresponding segment must begin at an
  86  *              address that is a multiple of (2**n).
  87  */
  88 struct exec
  89   {
  90     /* Standard stuff */
  91     unsigned long a_magic;      /* Identifies this as a b.out file      */
  92     unsigned long a_text;       /* Length of text                       */
  93     unsigned long a_data;       /* Length of data                       */
  94     unsigned long a_bss;        /* Length of runtime uninitialized data area */
  95     unsigned long a_syms;       /* Length of symbol table               */
  96     unsigned long a_entry;      /* Runtime start address                */
  97     unsigned long a_trsize;     /* Length of text relocation info       */
  98     unsigned long a_drsize;     /* Length of data relocation info       */
  99
 100     /* Added for i960 */
 101     unsigned long a_tload;      /* Text runtime load address            */
 102     unsigned long a_dload;      /* Data runtime load address            */
 103     unsigned char a_talign;     /* Alignment of text segment            */
 104     unsigned char a_dalign;     /* Alignment of data segment            */
 105     unsigned char a_balign;     /* Alignment of bss segment             */
 106     unsigned char a_relaxable;  /* Contains enough info to relax     */
 107   };
 108
 109 #define EXEC_BYTES_SIZE (10 * 4 + 4 * 1)
 110
 111 #define N_BADMAG(x)     (((x).a_magic)!=BMAGIC)
 112 #define N_TXTOFF(x)     EXEC_BYTES_SIZE
 113 #define N_DATOFF(x)     ( N_TXTOFF(x) + (x).a_text )
 114 #define N_TROFF(x)      ( N_DATOFF(x) + (x).a_data )
 115 #define N_DROFF(x)      ( N_TROFF(x) + (x).a_trsize )
 116 #define N_SYMOFF(x)     ( N_DROFF(x) + (x).a_drsize )
 117 #define N_STROFF(x)     ( N_SYMOFF(x) + (x).a_syms )
 118
 119 /* A single entry in the symbol table
 120  */
 121 struct nlist
 122   {
 123     union
 124       {
 125         char *n_name;
 126         struct nlist *n_next;
 127         long n_strx;            /* Index into string table      */
 128       }
 129     n_un;
 130     unsigned char n_type;       /* See below                            */
 131     char n_other;               /* Used in i80960 support -- see below  */
 132     short n_desc;
 133     unsigned long n_value;
 134   };
 135
 136 typedef struct nlist obj_symbol_type;
 137
 138 /* Legal values of n_type
 139  */
 140 #define N_UNDF  0               /* Undefined symbol     */
 141 #define N_ABS   2               /* Absolute symbol      */
 142 #define N_TEXT  4               /* Text symbol          */
 143 #define N_DATA  6               /* Data symbol          */
 144 #define N_BSS   8               /* BSS symbol           */
 145 #define N_FN    31              /* Filename symbol      */
 146
 147 #define N_EXT   1               /* External symbol (OR'd in with one of above)  */
 148 #define N_TYPE  036             /* Mask for all the type bits                   */
 149 #define N_STAB  0340            /* Mask for all bits used for SDB entries       */
 150
 151 #ifndef CUSTOM_RELOC_FORMAT
 152 struct relocation_info
 153   {
 154     int r_address;              /* File address of item to be relocated */
 155     unsigned
 156       r_index:24,               /* Index of symbol on which relocation is based*/
 157       r_pcrel:1,                /* 1 => relocate PC-relative; else absolute
 158                  *      On i960, pc-relative implies 24-bit
 159                  *      address, absolute implies 32-bit.
 160                  */
 161       r_length:2,               /* Number of bytes to relocate:
 162                  *      0 => 1 byte
 163                  *      1 => 2 bytes
 164                  *      2 => 4 bytes -- only value used for i960
 165                  */
 166       r_extern:1, r_bsr:1,      /* Something for the GNU NS32K assembler */
 167       r_disp:1,                 /* Something for the GNU NS32K assembler */
 168       r_callj:1,                /* 1 if relocation target is an i960 'callj' */
 169       nuthin:1;                 /* Unused                               */
 170   };
 171
 172 #endif /* CUSTOM_RELOC_FORMAT */
 173
 174 /*
 175  *  Macros to extract information from a symbol table entry.
 176  *  This syntactic indirection allows independence regarding a.out or coff.
 177  *  The argument (s) of all these macros is a pointer to a symbol table entry.
 178  */
 179
 180 /* Predicates */
 181 /* True if the symbol is external */
 182 #define S_IS_EXTERNAL(s)        ((s)->sy_symbol.n_type & N_EXT)
 183
 184 /* True if symbol has been defined, ie is in N_{TEXT,DATA,BSS,ABS} or N_EXT */
 185 #define S_IS_DEFINED(s)         ((S_GET_TYPE(s) != N_UNDF) || (S_GET_DESC(s) != 0))
 186
 187 /* Return true for symbols that should not be reduced to section
 188    symbols or eliminated from expressions, because they may be
 189    overridden by the linker.  */
 190 #define S_FORCE_RELOC(s, strict) \
 191   (!SEG_NORMAL (S_GET_SEGMENT (s)))
 192
 193 #define S_IS_COMMON(s) \
 194   (S_GET_TYPE (s) == N_UNDF && S_GET_VALUE (s) != 0)
 195
 196 #define S_IS_REGISTER(s)        ((s)->sy_symbol.n_type == N_REGISTER)
 197
 198 /* True if a debug special symbol entry */
 199 #define S_IS_DEBUG(s)           ((s)->sy_symbol.n_type & N_STAB)
 200 /* True if a symbol is local symbol name */
 201 #define S_IS_LOCAL(s)                                   \
 202   ((S_GET_NAME (s)                                      \
 203     && !S_IS_DEBUG (s)                                  \
 204     && (strchr (S_GET_NAME (s), '\001') != NULL         \
 205         || strchr (S_GET_NAME (s), '\002') != NULL      \
 206         || (S_LOCAL_NAME(s) && !flag_keep_locals)))     \
 207    || (flag_strip_local_absolute                        \
 208        && !S_IS_EXTERNAL(s)                             \
 209        && S_GET_SEGMENT(s) == absolute_section))
 210 /* True if a symbol is not defined in this file */
 211 #define S_IS_EXTERN(s)          ((s)->sy_symbol.n_type & N_EXT)
 212 /* True if the symbol has been generated because of a .stabd directive */
 213 #define S_IS_STABD(s)           (S_GET_NAME(s) == NULL)
 214
 215 /* Accessors */
 216 /* The name of the symbol */
 217 #define S_GET_NAME(s)           ((s)->sy_symbol.n_un.n_name)
 218 /* The pointer to the string table */
 219 #define S_GET_OFFSET(s)         ((s)->sy_symbol.n_un.n_strx)
 220 /* The type of the symbol */
 221 #define S_GET_TYPE(s)           ((s)->sy_symbol.n_type & N_TYPE)
 222 /* The numeric value of the segment */
 223 #define S_GET_SEGMENT(s)        (N_TYPE_seg[S_GET_TYPE(s)])
 224 /* The n_other expression value */
 225 #define S_GET_OTHER(s)          ((s)->sy_symbol.n_other)
 226 /* The n_desc expression value */
 227 #define S_GET_DESC(s)           ((s)->sy_symbol.n_desc)
 228
 229 /* Modifiers */
 230 /* Assume that a symbol cannot be simultaneously in more than on segment */
 231 /* set segment */
 232 #define S_SET_SEGMENT(s,seg)    ((s)->sy_symbol.n_type &= ~N_TYPE,(s)->sy_symbol.n_type|=SEGMENT_TO_SYMBOL_TYPE(seg))
 233 /* The symbol is external */
 234 #define S_SET_EXTERNAL(s)       ((s)->sy_symbol.n_type |= N_EXT)
 235 /* The symbol is not external */
 236 #define S_CLEAR_EXTERNAL(s)     ((s)->sy_symbol.n_type &= ~N_EXT)
 237 /* Set the name of the symbol */
 238 #define S_SET_NAME(s,v)         ((s)->sy_symbol.n_un.n_name = (v))
 239 /* Set the offset in the string table */
 240 #define S_SET_OFFSET(s,v)       ((s)->sy_symbol.n_un.n_strx = (v))
 241 /* Set the n_other expression value */
 242 #define S_SET_OTHER(s,v)        ((s)->sy_symbol.n_other = (v))
 243 /* Set the n_desc expression value */
 244 #define S_SET_DESC(s,v)         ((s)->sy_symbol.n_desc = (v))
 245 /* Set the n_type value */
 246 #define S_SET_TYPE(s,v)         ((s)->sy_symbol.n_type = (v))
 247
 248 /* File header macro and type definition */
 249
 250 #define H_GET_FILE_SIZE(h)      (EXEC_BYTES_SIZE + \
 251                                  H_GET_TEXT_SIZE(h) + H_GET_DATA_SIZE(h) + \
 252                                  H_GET_SYMBOL_TABLE_SIZE(h) + \
 253                                  H_GET_TEXT_RELOCATION_SIZE(h) + \
 254                                  H_GET_DATA_RELOCATION_SIZE(h) + \
 255                                  (h)->string_table_size)
 256
 257 #define H_GET_HEADER_SIZE(h)            EXEC_BYTES_SIZE
 258 #define H_GET_TEXT_SIZE(h)              ((h)->header.a_text)
 259 #define H_GET_DATA_SIZE(h)              ((h)->header.a_data)
 260 #define H_GET_BSS_SIZE(h)               ((h)->header.a_bss)
 261 #define H_GET_TEXT_RELOCATION_SIZE(h)   ((h)->header.a_trsize)
 262 #define H_GET_DATA_RELOCATION_SIZE(h)   ((h)->header.a_drsize)
 263 #define H_GET_SYMBOL_TABLE_SIZE(h)      ((h)->header.a_syms)
 264 #define H_GET_MAGIC_NUMBER(h)           ((h)->header.a_info)
 265 #define H_GET_ENTRY_POINT(h)            ((h)->header.a_entry)
 266 #define H_GET_STRING_SIZE(h)            ((h)->string_table_size)
 267 #define H_GET_LINENO_SIZE(h)            (0)
 268
 269 #ifdef EXEC_MACHINE_TYPE
 270 #define H_GET_MACHINE_TYPE(h)           ((h)->header.a_machtype)
 271 #endif /* EXEC_MACHINE_TYPE */
 272 #ifdef EXEC_VERSION
 273 #define H_GET_VERSION(h)                ((h)->header.a_version)
 274 #endif /* EXEC_VERSION */
 275
 276 #define H_SET_TEXT_SIZE(h,v)            ((h)->header.a_text = (v))
 277 #define H_SET_DATA_SIZE(h,v)            ((h)->header.a_data = (v))
 278 #define H_SET_BSS_SIZE(h,v)             ((h)->header.a_bss = (v))
 279
 280 #define H_SET_RELOCATION_SIZE(h,t,d)    (H_SET_TEXT_RELOCATION_SIZE((h),(t)),\
 281                                          H_SET_DATA_RELOCATION_SIZE((h),(d)))
 282
 283 #define H_SET_TEXT_RELOCATION_SIZE(h,v) ((h)->header.a_trsize = (v))
 284 #define H_SET_DATA_RELOCATION_SIZE(h,v) ((h)->header.a_drsize = (v))
 285 #define H_SET_SYMBOL_TABLE_SIZE(h,v)    ((h)->header.a_syms = (v) * 12)
 286
 287 #define H_SET_MAGIC_NUMBER(h,v)         ((h)->header.a_magic = (v))
 288
 289 #define H_SET_ENTRY_POINT(h,v)          ((h)->header.a_entry = (v))
 290 #define H_SET_STRING_SIZE(h,v)          ((h)->string_table_size = (v))
 291 #ifdef EXEC_MACHINE_TYPE
 292 #define H_SET_MACHINE_TYPE(h,v)         ((h)->header.a_machtype = (v))
 293 #endif /* EXEC_MACHINE_TYPE */
 294 #ifdef EXEC_VERSION
 295 #define H_SET_VERSION(h,v)              ((h)->header.a_version = (v))
 296 #endif /* EXEC_VERSION */
 297
 298 typedef struct
 299   {
 300     struct exec header;         /* a.out header */
 301     long string_table_size;     /* names + '\0' + sizeof (int) */
 302   }
 303
 304 object_headers;
 305
 306 /* unused hooks.  */
 307 #define OBJ_EMIT_LINENO(a, b, c)        {;}
 308 #define obj_pre_write_hook(a)           {;}
 309
 310 #if WORDS_BIGENDIAN
 311 #define host_number_to_chars number_to_chars_bigendian
 312 #else
 313 #define host_number_to_chars number_to_chars_littleendian
 314 #endif
 315
 316 #if __STDC__
 317 struct fix;
 318 #endif
 319 extern void tc_aout_fix_to_chars PARAMS ((char *where,
 320                                           struct fix *fixP,
 321                                           relax_addressT segment_address));
 322 extern void tc_bout_fix_to_chars PARAMS ((char *where,
 323                                           struct fix *fixP,
 324                                           relax_addressT segment_address));
 325
 326 #define AOUT_STABS