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
= xmalloc (suffix_dotdot
- prefix_dotdot
+ 1);
277 strncpy (base_id
, &id
[prefix_dotdot
], suffix_dotdot
- prefix_dotdot
);
278 base_id
[suffix_dotdot
- prefix_dotdot
] = 0;
280 if (strlen (base_id
) > MAX_LABEL_LENGTH
)
285 strcpy (new_id
, base_id
);
288 strcpy (new_id
, shorten_identifier (new_id
));
290 /* Prepend back the prefix if there was one. */
293 memmove (&new_id
[prefix_dotdot
], new_id
, strlen (new_id
) + 1);
294 strncpy (new_id
, prefix
, prefix_dotdot
);
297 /* Append back the suffix if there was one. */
299 strcat (new_id
, suffix
);
301 /* Save it on the heap and return. */
302 return_id
= xmalloc (strlen (new_id
) + 1);
303 strcpy (return_id
, new_id
);
311 /* The code below implements a mechanism for truncating long
312 identifiers to an arbitrary length (set by MAX_LABEL_LENGTH).
314 It attempts to make each truncated identifier unique by replacing
315 part of the identifier with an encoded 32-bit CRC and an associated
316 checksum (the checksum is used as a way to determine that the name
319 Note that both a portion of the start and of the end of the
320 identifier may be kept. The macro ID_SUFFIX_LENGTH will return the
321 number of characters in the suffix of the identifier that should be
324 The portion of the identifier that is going to be removed is
325 checksummed. The checksum is then encoded as a 5-character string,
326 the characters of which are then summed. This sum is then encoded
327 as a 3-character string. Finally, the original length of the
328 identifier is encoded as a 3-character string.
330 These three strings are then concatenated together (along with an _h
331 which further designates that the name was truncated):
333 "original_identifier"_haaaaabbbccc
336 bbb = length of original identifier
337 ccc = sum of 32-bit CRC characters
339 The resulting identifier will be MAX_LABEL_LENGTH characters long.
344 /* Table used to convert an integer into a string. */
346 static const char codings
[] = {
347 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o',
348 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
349 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O',
350 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
351 '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '_'};
353 /* The number of codings in the above table. */
354 static const int number_of_codings
= sizeof (codings
) / sizeof (char);
356 /* Table used by decode_16 () to convert an encoded string back into
358 static char decodings
[256];
360 /* Table used by the crc32 function to calcuate the checksum. */
361 static unsigned int crc32_table
[256] = {0, 0};
363 /* Given a string in BUF, calculate a 32-bit CRC for it.
365 This is used as a reasonably unique hash for the given string. */
368 crc32 (unsigned char *buf
, int len
)
370 unsigned int crc
= 0xffffffff;
372 if (! crc32_table
[1])
374 /* Initialize the CRC table and the decoding table. */
378 for (i
= 0; i
< 256; i
++)
380 for (c
= i
<< 24, j
= 8; j
> 0; --j
)
381 c
= c
& 0x80000000 ? (c
<< 1) ^ 0x04c11db7 : (c
<< 1);
385 for (i
= 0; i
< number_of_codings
; i
++)
386 decodings
[codings
[i
] & 255] = i
;
391 crc
= (crc
<< 8) ^ crc32_table
[(crc
>> 24) ^ *buf
];
397 /* Encode the lower 32 bits of VALUE as a 5-character string. */
400 encode_32 (unsigned int value
)
406 for(x
= 0; x
< 5; x
++)
408 res
[x
] = codings
[value
% number_of_codings
];
409 value
= value
/ number_of_codings
;
414 /* Encode the lower 16 bits of VALUE as a 3-character string. */
417 encode_16 (unsigned int value
)
423 for(x
= 0; x
< 3; x
++)
425 res
[x
] = codings
[value
% number_of_codings
];
426 value
= value
/ number_of_codings
;
431 /* Convert the encoded string obtained from encode_16 () back into a
435 decode_16 (const char *string
)
437 return decodings
[(int) string
[2]] * number_of_codings
* number_of_codings
438 + decodings
[(int) string
[1]] * number_of_codings
439 + decodings
[(int) string
[0]];
442 /* ID_SUFFIX_LENGTH is used to determine how many characters in the
443 suffix of the identifier are to be preserved, if any. */
445 #ifndef ID_SUFFIX_LENGTH
446 #define ID_SUFFIX_LENGTH(ID) (0)
449 /* Return a reasonably-unique version of NAME that is less than or
450 equal to MAX_LABEL_LENGTH characters long. The string returned from
451 this function may be a copy of NAME; the function will never
452 actually modify the contents of NAME. */
454 static char newname
[MAX_LABEL_LENGTH
+ 1];
457 shorten_identifier (char *name
)
459 int crc
, len
, sum
, x
, final_len
;
461 int suffix_length
= ID_SUFFIX_LENGTH (name
);
463 if ((len
= strlen (name
)) <= MAX_LABEL_LENGTH
)
466 final_len
= MAX_LABEL_LENGTH
- 2 - 5 - 3 - 3 - suffix_length
;
467 crc
= crc32 ((unsigned char *)name
+ final_len
,
468 len
- final_len
- suffix_length
);
469 crc_chars
= encode_32 (crc
);
471 for (x
= 0; x
< 5; x
++)
472 sum
+= crc_chars
[x
];
473 strncpy (newname
, name
, final_len
);
474 newname
[MAX_LABEL_LENGTH
] = 0;
475 /* Now append the suffix of the original identifier, if any. */
477 strncpy (newname
+ MAX_LABEL_LENGTH
- suffix_length
,
478 name
+ len
- suffix_length
,
480 strncpy (newname
+ final_len
, "_h", 2);
481 strncpy (newname
+ final_len
+ 2 , crc_chars
, 5);
482 strncpy (newname
+ final_len
+ 2 + 5, encode_16 (len
), 3);
483 strncpy (newname
+ final_len
+ 2 + 5 + 3, encode_16 (sum
), 3);
484 if (!is_truncated_identifier (newname
))
489 /* Determine whether or not ID is a truncated identifier, and return a
490 non-zero value if it is. */
493 is_truncated_identifier (char *id
)
496 int len
= strlen (id
);
497 /* If it's not exactly MAX_LABEL_LENGTH characters long, it can't be
498 a truncated identifier. */
499 if (len
!= MAX_LABEL_LENGTH
)
502 /* Start scanning backwards for a _h. */
503 len
= len
- 3 - 3 - 5 - 2;
507 if (ptr
[0] == '_' && ptr
[1] == 'h')
509 /* Now see if the sum encoded in the identifer matches. */
512 for (x
= 0; x
< 5; x
++)
514 /* If it matches, this is probably a truncated identifier. */
515 if (sum
== decode_16 (ptr
+ 5 + 2 + 3))
523 /* end of obj-evax.c */