1 /* obj-evax.c - EVAX (openVMS/Alpha) object file format.
2 Copyright (C) 1996-2016 Free Software Foundation, Inc.
3 Contributed by Klaus Kämpf (kkaempf@progis.de) of
4 proGIS Software, Aachen, Germany.
5 Extensively enhanced by Douglas Rupp of AdaCore.
7 This file is part of GAS, the GNU Assembler
9 GAS is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; either version 3, or (at your option)
14 GAS is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
19 You should have received a copy of the GNU General Public License
20 along with GAS; see the file COPYING. If not, write to
21 the Free Software Foundation, 51 Franklin Street - Fifth Floor, Boston,
22 MA 02110-1301, USA. */
24 #define OBJ_HEADER "obj-evax.h"
30 #include "struc-symbol.h"
31 #include "safe-ctype.h"
33 static void s_evax_weak (int);
34 static unsigned int crc32 (unsigned char *, int);
35 static char *encode_32 (unsigned int);
36 static char *encode_16 (unsigned int);
37 static int decode_16 (const char *);
39 const pseudo_typeS obj_pseudo_table
[] =
41 { "weak", s_evax_weak
, 0},
43 }; /* obj_pseudo_table */
45 void obj_read_begin_hook () {}
47 /* Handle the weak specific pseudo-op. */
50 s_evax_weak (int ignore ATTRIBUTE_UNUSED
)
59 stop
= mri_comment_field (&stopc
);
63 c
= get_symbol_name (&name
);
64 symbolP
= symbol_find_or_make (name
);
65 (void) restore_line_pointer (c
);
72 if (*input_line_pointer
== '\n')
79 mri_comment_end (stop
, stopc
);
81 demand_empty_rest_of_line ();
85 evax_symbol_new_hook (symbolS
*sym
)
87 struct evax_private_udata_struct
*udata
;
89 udata
= (struct evax_private_udata_struct
*)
90 xmalloc (sizeof (struct evax_private_udata_struct
));
92 udata
->bsym
= symbol_get_bfdsym (sym
);
94 udata
->origname
= xstrdup (S_GET_NAME (sym
));
96 symbol_get_bfdsym(sym
)->udata
.p
= (PTR
) udata
;
100 evax_frob_symbol (symbolS
*sym
, int *punt
)
102 const char *symname
= S_GET_NAME (sym
);
103 int symlen
= strlen (symname
);
104 asymbol
*symbol
= symbol_get_bfdsym (sym
);
107 && strcmp (symname
+ symlen
- 4, "..en") == 0
108 && S_GET_SEGMENT (sym
) == undefined_section
)
110 symbol_clear_used_in_reloc (sym
);
114 else if ((symbol
->flags
& BSF_GLOBAL
) && (symbol
->flags
& BSF_FUNCTION
))
116 struct evax_private_udata_struct
*udata
117 = (struct evax_private_udata_struct
*)symbol
->udata
.p
;
119 /* Fix up equates of function definitions. */
120 while (udata
->enbsym
== NULL
)
122 /* ??? Equates have been resolved at this point so their
123 expression is O_constant; but they previously were
124 O_symbol and we hope the equated symbol is still there. */
125 sym
= symbol_get_value_expression (sym
)->X_add_symbol
;
128 as_bad (_("no entry symbol for global function '%s'"), symname
);
131 symbol
= symbol_get_bfdsym (sym
);
133 = ((struct evax_private_udata_struct
*)symbol
->udata
.p
)->enbsym
;
139 evax_frob_file_before_adjust (void)
141 struct alpha_linkage_fixups
*l
;
142 segT current_section
= now_seg
;
143 int current_subsec
= now_subseg
;
144 segment_info_type
*seginfo
;
145 int linkage_index
= 1;
147 subseg_set (alpha_link_section
, 0);
148 seginfo
= seg_info (alpha_link_section
);
150 /* Handle .linkage fixups. */
151 for (l
= alpha_linkage_fixup_root
; l
!= NULL
; l
= l
->next
)
153 if (S_GET_SEGMENT (l
->fixp
->fx_addsy
) == alpha_link_section
)
155 /* The symbol is defined in the file. The linkage entry decays to
158 fixS
*fixpentry
, *fixppdesc
, *fixtail
;
160 fixtail
= seginfo
->fix_tail
;
162 /* Replace the linkage with the local symbols */
163 entry_sym
= symbol_find
164 (((struct evax_private_udata_struct
*)symbol_get_bfdsym (l
->fixp
->fx_addsy
)->udata
.p
)->enbsym
->name
);
167 fixpentry
= fix_new (l
->fixp
->fx_frag
, l
->fixp
->fx_where
, 8,
168 entry_sym
, l
->fixp
->fx_offset
, 0,
170 fixppdesc
= fix_new (l
->fixp
->fx_frag
, l
->fixp
->fx_where
+ 8, 8,
171 l
->fixp
->fx_addsy
, l
->fixp
->fx_offset
, 0,
173 l
->fixp
->fx_size
= 0;
174 l
->fixp
->fx_done
= 1;
176 /* If not already at the tail, splice the new fixups into
177 the chain right after the one we are nulling out */
178 if (fixtail
!= l
->fixp
)
180 fixppdesc
->fx_next
= l
->fixp
->fx_next
;
181 l
->fixp
->fx_next
= fixpentry
;
182 fixtail
->fx_next
= 0;
183 seginfo
->fix_tail
= fixtail
;
188 /* Assign a linkage index. */
189 ((struct evax_private_udata_struct
*)
190 symbol_get_bfdsym (l
->label
)->udata
.p
)->lkindex
= linkage_index
;
192 l
->fixp
->fx_addnumber
= linkage_index
;
198 subseg_set (current_section
, current_subsec
);
202 evax_frob_file_before_fix (void)
204 /* Now that the fixups are done earlier, we need to transfer the values
205 into the BFD symbols before calling fix_segment (ideally should not
206 be done also later). */
211 /* Set the value into the BFD symbol. Up til now the value
212 has only been kept in the gas symbolS struct. */
213 for (symp
= symbol_rootP
; symp
; symp
= symbol_next (symp
))
214 symbol_get_bfdsym (symp
)->value
= S_GET_VALUE (symp
);
218 /* The length is computed from the maximum allowable length of 64 less the
219 4 character ..xx extension that must be preserved (removed before
220 krunching and appended back on afterwards). The $<nnn>.. prefix is
221 also removed and prepened back on, but doesn't enter into the length
222 computation because symbols with that prefix are always resolved
223 by the assembler and will never appear in the symbol table. At least
224 I hope that's true, TBD. */
225 #define MAX_LABEL_LENGTH 60
227 static char *shorten_identifier (char *);
228 static int is_truncated_identifier (char *);
231 evax_shorten_name (char *id
)
233 int prefix_dotdot
= 0;
235 int len
= strlen (id
);
236 int suffix_dotdot
= len
;
240 /* This test may be too conservative. */
241 if (len
<= MAX_LABEL_LENGTH
)
247 /* Check for ..xx suffix and save it. */
248 if (strncmp (&id
[len
-4], "..", 2) == 0)
250 suffix_dotdot
= len
- 4;
251 strncpy (suffix
, &id
[len
-4], 4);
255 /* Check for $<nnn>.. prefix and save it. */
256 if ((id
[0] == '$') && ISDIGIT (id
[1]))
260 for (i
=2; i
< len
; i
++)
262 if (!ISDIGIT (id
[i
]))
264 if (id
[i
] == '.' && id
[i
+1] == '.')
267 strncpy (prefix
, id
, prefix_dotdot
);
268 prefix
[prefix_dotdot
] = 0;
275 /* We only need worry about krunching the base symbol. */
276 base_id
= xmemdup0 (&id
[prefix_dotdot
], suffix_dotdot
- prefix_dotdot
);
278 if (strlen (base_id
) > MAX_LABEL_LENGTH
)
283 strcpy (new_id
, base_id
);
286 strcpy (new_id
, shorten_identifier (new_id
));
288 /* Prepend back the prefix if there was one. */
291 memmove (&new_id
[prefix_dotdot
], new_id
, strlen (new_id
) + 1);
292 strncpy (new_id
, prefix
, prefix_dotdot
);
295 /* Append back the suffix if there was one. */
297 strcat (new_id
, suffix
);
299 /* Save it on the heap and return. */
300 return_id
= xstrdup (new_id
);
308 /* The code below implements a mechanism for truncating long
309 identifiers to an arbitrary length (set by MAX_LABEL_LENGTH).
311 It attempts to make each truncated identifier unique by replacing
312 part of the identifier with an encoded 32-bit CRC and an associated
313 checksum (the checksum is used as a way to determine that the name
316 Note that both a portion of the start and of the end of the
317 identifier may be kept. The macro ID_SUFFIX_LENGTH will return the
318 number of characters in the suffix of the identifier that should be
321 The portion of the identifier that is going to be removed is
322 checksummed. The checksum is then encoded as a 5-character string,
323 the characters of which are then summed. This sum is then encoded
324 as a 3-character string. Finally, the original length of the
325 identifier is encoded as a 3-character string.
327 These three strings are then concatenated together (along with an _h
328 which further designates that the name was truncated):
330 "original_identifier"_haaaaabbbccc
333 bbb = length of original identifier
334 ccc = sum of 32-bit CRC characters
336 The resulting identifier will be MAX_LABEL_LENGTH characters long.
341 /* Table used to convert an integer into a string. */
343 static const char codings
[] = {
344 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o',
345 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
346 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O',
347 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
348 '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '_'};
350 /* The number of codings in the above table. */
351 static const int number_of_codings
= sizeof (codings
) / sizeof (char);
353 /* Table used by decode_16 () to convert an encoded string back into
355 static char decodings
[256];
357 /* Table used by the crc32 function to calcuate the checksum. */
358 static unsigned int crc32_table
[256] = {0, 0};
360 /* Given a string in BUF, calculate a 32-bit CRC for it.
362 This is used as a reasonably unique hash for the given string. */
365 crc32 (unsigned char *buf
, int len
)
367 unsigned int crc
= 0xffffffff;
369 if (! crc32_table
[1])
371 /* Initialize the CRC table and the decoding table. */
375 for (i
= 0; i
< 256; i
++)
377 for (c
= i
<< 24, j
= 8; j
> 0; --j
)
378 c
= c
& 0x80000000 ? (c
<< 1) ^ 0x04c11db7 : (c
<< 1);
382 for (i
= 0; i
< number_of_codings
; i
++)
383 decodings
[codings
[i
] & 255] = i
;
388 crc
= (crc
<< 8) ^ crc32_table
[(crc
>> 24) ^ *buf
];
394 /* Encode the lower 32 bits of VALUE as a 5-character string. */
397 encode_32 (unsigned int value
)
403 for(x
= 0; x
< 5; x
++)
405 res
[x
] = codings
[value
% number_of_codings
];
406 value
= value
/ number_of_codings
;
411 /* Encode the lower 16 bits of VALUE as a 3-character string. */
414 encode_16 (unsigned int value
)
420 for(x
= 0; x
< 3; x
++)
422 res
[x
] = codings
[value
% number_of_codings
];
423 value
= value
/ number_of_codings
;
428 /* Convert the encoded string obtained from encode_16 () back into a
432 decode_16 (const char *string
)
434 return decodings
[(int) string
[2]] * number_of_codings
* number_of_codings
435 + decodings
[(int) string
[1]] * number_of_codings
436 + decodings
[(int) string
[0]];
439 /* ID_SUFFIX_LENGTH is used to determine how many characters in the
440 suffix of the identifier are to be preserved, if any. */
442 #ifndef ID_SUFFIX_LENGTH
443 #define ID_SUFFIX_LENGTH(ID) (0)
446 /* Return a reasonably-unique version of NAME that is less than or
447 equal to MAX_LABEL_LENGTH characters long. The string returned from
448 this function may be a copy of NAME; the function will never
449 actually modify the contents of NAME. */
451 static char newname
[MAX_LABEL_LENGTH
+ 1];
454 shorten_identifier (char *name
)
456 int crc
, len
, sum
, x
, final_len
;
458 int suffix_length
= ID_SUFFIX_LENGTH (name
);
460 if ((len
= strlen (name
)) <= MAX_LABEL_LENGTH
)
463 final_len
= MAX_LABEL_LENGTH
- 2 - 5 - 3 - 3 - suffix_length
;
464 crc
= crc32 ((unsigned char *)name
+ final_len
,
465 len
- final_len
- suffix_length
);
466 crc_chars
= encode_32 (crc
);
468 for (x
= 0; x
< 5; x
++)
469 sum
+= crc_chars
[x
];
470 strncpy (newname
, name
, final_len
);
471 newname
[MAX_LABEL_LENGTH
] = 0;
472 /* Now append the suffix of the original identifier, if any. */
474 strncpy (newname
+ MAX_LABEL_LENGTH
- suffix_length
,
475 name
+ len
- suffix_length
,
477 strncpy (newname
+ final_len
, "_h", 2);
478 strncpy (newname
+ final_len
+ 2 , crc_chars
, 5);
479 strncpy (newname
+ final_len
+ 2 + 5, encode_16 (len
), 3);
480 strncpy (newname
+ final_len
+ 2 + 5 + 3, encode_16 (sum
), 3);
481 if (!is_truncated_identifier (newname
))
486 /* Determine whether or not ID is a truncated identifier, and return a
487 non-zero value if it is. */
490 is_truncated_identifier (char *id
)
493 int len
= strlen (id
);
494 /* If it's not exactly MAX_LABEL_LENGTH characters long, it can't be
495 a truncated identifier. */
496 if (len
!= MAX_LABEL_LENGTH
)
499 /* Start scanning backwards for a _h. */
500 len
= len
- 3 - 3 - 5 - 2;
504 if (ptr
[0] == '_' && ptr
[1] == 'h')
506 /* Now see if the sum encoded in the identifer matches. */
509 for (x
= 0; x
< 5; x
++)
511 /* If it matches, this is probably a truncated identifier. */
512 if (sum
== decode_16 (ptr
+ 5 + 2 + 3))
520 /* end of obj-evax.c */