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