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252b5132 | 1 | /* frags.c - manage frags - |
219d1afa | 2 | Copyright (C) 1987-2018 Free Software Foundation, Inc. |
252b5132 RH |
3 | |
4 | This file is part of GAS, the GNU Assembler. | |
5 | ||
6 | GAS is free software; you can redistribute it and/or modify | |
7 | it under the terms of the GNU General Public License as published by | |
ec2655a6 | 8 | the Free Software Foundation; either version 3, or (at your option) |
252b5132 RH |
9 | any later version. |
10 | ||
11 | GAS is distributed in the hope that it will be useful, | |
12 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | GNU General Public License for more details. | |
15 | ||
16 | You should have received a copy of the GNU General Public License | |
17 | along with GAS; see the file COPYING. If not, write to the Free | |
4b4da160 NC |
18 | Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA |
19 | 02110-1301, USA. */ | |
252b5132 RH |
20 | |
21 | #include "as.h" | |
22 | #include "subsegs.h" | |
23 | #include "obstack.h" | |
24 | ||
25 | extern fragS zero_address_frag; | |
6885131b | 26 | extern fragS predefined_address_frag; |
a82c7d90 DW |
27 | |
28 | static int totalfrags; | |
29 | ||
30 | int | |
31 | get_frag_count (void) | |
32 | { | |
33 | return totalfrags; | |
34 | } | |
35 | ||
36 | void | |
37 | clear_frag_count (void) | |
38 | { | |
39 | totalfrags = 0; | |
40 | } | |
252b5132 RH |
41 | \f |
42 | /* Initialization for frag routines. */ | |
29f8404c | 43 | |
252b5132 | 44 | void |
dd625418 | 45 | frag_init (void) |
252b5132 RH |
46 | { |
47 | zero_address_frag.fr_type = rs_fill; | |
6885131b | 48 | predefined_address_frag.fr_type = rs_fill; |
252b5132 RH |
49 | } |
50 | \f | |
e85ca5bb AM |
51 | /* Check that we're not trying to assemble into a section that can't |
52 | allocate frags (currently, this is only possible in the absolute | |
53 | section), or into an mri common. */ | |
54 | ||
55 | static void | |
56 | frag_alloc_check (const struct obstack *ob) | |
57 | { | |
58 | if (ob->chunk_size == 0) | |
59 | { | |
60 | as_bad (_("attempt to allocate data in absolute section")); | |
61 | subseg_set (text_section, 0); | |
62 | } | |
63 | ||
64 | if (mri_common_symbol != NULL) | |
65 | { | |
66 | as_bad (_("attempt to allocate data in common section")); | |
67 | mri_common_symbol = NULL; | |
68 | } | |
69 | } | |
70 | ||
252b5132 RH |
71 | /* Allocate a frag on the specified obstack. |
72 | Call this routine from everywhere else, so that all the weird alignment | |
73 | hackery can be done in just one place. */ | |
29f8404c | 74 | |
252b5132 | 75 | fragS * |
dd625418 | 76 | frag_alloc (struct obstack *ob) |
252b5132 RH |
77 | { |
78 | fragS *ptr; | |
79 | int oalign; | |
80 | ||
81 | (void) obstack_alloc (ob, 0); | |
82 | oalign = obstack_alignment_mask (ob); | |
83 | obstack_alignment_mask (ob) = 0; | |
1e9cc1c2 | 84 | ptr = (fragS *) obstack_alloc (ob, SIZEOF_STRUCT_FRAG); |
252b5132 RH |
85 | obstack_alignment_mask (ob) = oalign; |
86 | memset (ptr, 0, SIZEOF_STRUCT_FRAG); | |
a82c7d90 | 87 | totalfrags++; |
252b5132 RH |
88 | return ptr; |
89 | } | |
90 | \f | |
088b3cd0 | 91 | /* Try to augment current frag by nchars chars. |
29f8404c | 92 | If there is no room, close of the current frag with a ".fill 0" |
088b3cd0 TG |
93 | and begin a new frag. Unless the new frag has nchars chars available |
94 | do not return. Do not set up any fields of *now_frag. */ | |
29f8404c KH |
95 | |
96 | void | |
e57e6ddc | 97 | frag_grow (size_t nchars) |
252b5132 RH |
98 | { |
99 | if (obstack_room (&frchain_now->frch_obstack) < nchars) | |
100 | { | |
e57e6ddc AM |
101 | size_t oldc; |
102 | size_t newc; | |
252b5132 | 103 | |
ee192366 MM |
104 | /* Try to allocate a bit more than needed right now. But don't do |
105 | this if we would waste too much memory. Especially necessary | |
8d8385cf | 106 | for extremely big (like 2GB initialized) frags. */ |
ee192366 | 107 | if (nchars < 0x10000) |
8d8385cf | 108 | newc = 2 * nchars; |
ee192366 | 109 | else |
8d8385cf TG |
110 | newc = nchars + 0x10000; |
111 | newc += SIZEOF_STRUCT_FRAG; | |
112 | ||
113 | /* Check for possible overflow. */ | |
e57e6ddc | 114 | if (newc < nchars) |
992a06ee AM |
115 | as_fatal (ngettext ("can't extend frag %lu char", |
116 | "can't extend frag %lu chars", | |
117 | (unsigned long) nchars), | |
118 | (unsigned long) nchars); | |
8d8385cf | 119 | |
3db8daf3 MR |
120 | /* Force to allocate at least NEWC bytes, but not less than the |
121 | default. */ | |
8d8385cf | 122 | oldc = obstack_chunk_size (&frchain_now->frch_obstack); |
3db8daf3 MR |
123 | if (newc > oldc) |
124 | obstack_chunk_size (&frchain_now->frch_obstack) = newc; | |
8d8385cf TG |
125 | |
126 | while (obstack_room (&frchain_now->frch_obstack) < nchars) | |
127 | { | |
128 | /* Not enough room in this frag. Close it and start a new one. | |
129 | This must be done in a loop because the created frag may not | |
130 | be big enough if the current obstack chunk is used. */ | |
131 | frag_wane (frag_now); | |
132 | frag_new (0); | |
133 | } | |
134 | ||
135 | /* Restore the old chunk size. */ | |
136 | obstack_chunk_size (&frchain_now->frch_obstack) = oldc; | |
252b5132 | 137 | } |
252b5132 RH |
138 | } |
139 | \f | |
29f8404c KH |
140 | /* Call this to close off a completed frag, and start up a new (empty) |
141 | frag, in the same subsegment as the old frag. | |
142 | [frchain_now remains the same but frag_now is updated.] | |
143 | Because this calculates the correct value of fr_fix by | |
144 | looking at the obstack 'frags', it needs to know how many | |
145 | characters at the end of the old frag belong to the maximal | |
146 | variable part; The rest must belong to fr_fix. | |
147 | It doesn't actually set up the old frag's fr_var. You may have | |
148 | set fr_var == 1, but allocated 10 chars to the end of the frag; | |
149 | In this case you pass old_frags_var_max_size == 10. | |
150 | In fact, you may use fr_var for something totally unrelated to the | |
151 | size of the variable part of the frag; None of the generic frag | |
152 | handling code makes use of fr_var. | |
153 | ||
154 | Make a new frag, initialising some components. Link new frag at end | |
155 | of frchain_now. */ | |
156 | ||
157 | void | |
e57e6ddc | 158 | frag_new (size_t old_frags_var_max_size |
dd625418 KH |
159 | /* Number of chars (already allocated on obstack frags) in |
160 | variable_length part of frag. */) | |
252b5132 RH |
161 | { |
162 | fragS *former_last_fragP; | |
163 | frchainS *frchP; | |
164 | ||
9c2799c2 | 165 | gas_assert (frchain_now->frch_last == frag_now); |
252b5132 RH |
166 | |
167 | /* Fix up old frag's fr_fix. */ | |
bea9907b | 168 | frag_now->fr_fix = frag_now_fix_octets () - old_frags_var_max_size; |
252b5132 | 169 | /* Make sure its type is valid. */ |
9c2799c2 | 170 | gas_assert (frag_now->fr_type != 0); |
252b5132 RH |
171 | |
172 | /* This will align the obstack so the next struct we allocate on it | |
29f8404c | 173 | will begin at a correct boundary. */ |
252b5132 RH |
174 | obstack_finish (&frchain_now->frch_obstack); |
175 | frchP = frchain_now; | |
176 | know (frchP); | |
177 | former_last_fragP = frchP->frch_last; | |
9c2799c2 NC |
178 | gas_assert (former_last_fragP != 0); |
179 | gas_assert (former_last_fragP == frag_now); | |
252b5132 RH |
180 | frag_now = frag_alloc (&frchP->frch_obstack); |
181 | ||
3b4dbbbf | 182 | frag_now->fr_file = as_where (&frag_now->fr_line); |
252b5132 RH |
183 | |
184 | /* Generally, frag_now->points to an address rounded up to next | |
185 | alignment. However, characters will add to obstack frags | |
186 | IMMEDIATELY after the struct frag, even if they are not starting | |
29f8404c | 187 | at an alignment address. */ |
252b5132 RH |
188 | former_last_fragP->fr_next = frag_now; |
189 | frchP->frch_last = frag_now; | |
190 | ||
191 | #ifndef NO_LISTING | |
192 | { | |
193 | extern struct list_info_struct *listing_tail; | |
194 | frag_now->line = listing_tail; | |
195 | } | |
196 | #endif | |
197 | ||
9c2799c2 | 198 | gas_assert (frchain_now->frch_last == frag_now); |
252b5132 RH |
199 | |
200 | frag_now->fr_next = NULL; | |
29f8404c | 201 | } |
252b5132 | 202 | \f |
29f8404c KH |
203 | /* Start a new frag unless we have n more chars of room in the current frag. |
204 | Close off the old frag with a .fill 0. | |
205 | ||
206 | Return the address of the 1st char to write into. Advance | |
207 | frag_now_growth past the new chars. */ | |
252b5132 RH |
208 | |
209 | char * | |
e57e6ddc | 210 | frag_more (size_t nchars) |
252b5132 | 211 | { |
ed9e98c2 | 212 | char *retval; |
252b5132 | 213 | |
e85ca5bb | 214 | frag_alloc_check (&frchain_now->frch_obstack); |
252b5132 RH |
215 | frag_grow (nchars); |
216 | retval = obstack_next_free (&frchain_now->frch_obstack); | |
217 | obstack_blank_fast (&frchain_now->frch_obstack, nchars); | |
ed9e98c2 | 218 | return retval; |
29f8404c | 219 | } |
252b5132 | 220 | \f |
69b1d605 TG |
221 | /* Close the current frag, setting its fields for a relaxable frag. Start a |
222 | new frag. */ | |
29f8404c | 223 | |
69b1d605 | 224 | static void |
e57e6ddc AM |
225 | frag_var_init (relax_stateT type, size_t max_chars, size_t var, |
226 | relax_substateT subtype, symbolS *symbol, offsetT offset, | |
69b1d605 | 227 | char *opcode) |
252b5132 | 228 | { |
252b5132 RH |
229 | frag_now->fr_var = var; |
230 | frag_now->fr_type = type; | |
231 | frag_now->fr_subtype = subtype; | |
232 | frag_now->fr_symbol = symbol; | |
233 | frag_now->fr_offset = offset; | |
234 | frag_now->fr_opcode = opcode; | |
235 | #ifdef USING_CGEN | |
236 | frag_now->fr_cgen.insn = 0; | |
237 | frag_now->fr_cgen.opindex = 0; | |
238 | frag_now->fr_cgen.opinfo = 0; | |
239 | #endif | |
240 | #ifdef TC_FRAG_INIT | |
241 | TC_FRAG_INIT (frag_now); | |
242 | #endif | |
3b4dbbbf | 243 | frag_now->fr_file = as_where (&frag_now->fr_line); |
69b1d605 | 244 | |
252b5132 | 245 | frag_new (max_chars); |
69b1d605 TG |
246 | } |
247 | ||
248 | /* Start a new frag unless we have max_chars more chars of room in the | |
249 | current frag. Close off the old frag with a .fill 0. | |
250 | ||
251 | Set up a machine_dependent relaxable frag, then start a new frag. | |
252 | Return the address of the 1st char of the var part of the old frag | |
253 | to write into. */ | |
254 | ||
255 | char * | |
e57e6ddc AM |
256 | frag_var (relax_stateT type, size_t max_chars, size_t var, |
257 | relax_substateT subtype, symbolS *symbol, offsetT offset, | |
258 | char *opcode) | |
69b1d605 | 259 | { |
ed9e98c2 | 260 | char *retval; |
69b1d605 TG |
261 | |
262 | frag_grow (max_chars); | |
263 | retval = obstack_next_free (&frchain_now->frch_obstack); | |
264 | obstack_blank_fast (&frchain_now->frch_obstack, max_chars); | |
265 | frag_var_init (type, max_chars, var, subtype, symbol, offset, opcode); | |
266 | return retval; | |
252b5132 RH |
267 | } |
268 | \f | |
29f8404c KH |
269 | /* OVE: This variant of frag_var assumes that space for the tail has been |
270 | allocated by caller. | |
271 | No call to frag_grow is done. */ | |
252b5132 RH |
272 | |
273 | char * | |
e57e6ddc | 274 | frag_variant (relax_stateT type, size_t max_chars, size_t var, |
dd625418 KH |
275 | relax_substateT subtype, symbolS *symbol, offsetT offset, |
276 | char *opcode) | |
252b5132 | 277 | { |
ed9e98c2 | 278 | char *retval; |
252b5132 RH |
279 | |
280 | retval = obstack_next_free (&frchain_now->frch_obstack); | |
69b1d605 TG |
281 | frag_var_init (type, max_chars, var, subtype, symbol, offset, opcode); |
282 | ||
283 | return retval; | |
29f8404c | 284 | } |
252b5132 | 285 | \f |
29f8404c KH |
286 | /* Reduce the variable end of a frag to a harmless state. */ |
287 | ||
288 | void | |
ed9e98c2 | 289 | frag_wane (fragS *fragP) |
252b5132 RH |
290 | { |
291 | fragP->fr_type = rs_fill; | |
292 | fragP->fr_offset = 0; | |
293 | fragP->fr_var = 0; | |
0530d30a RS |
294 | } |
295 | \f | |
296 | /* Return the number of bytes by which the current frag can be grown. */ | |
297 | ||
e57e6ddc | 298 | size_t |
0530d30a RS |
299 | frag_room (void) |
300 | { | |
301 | return obstack_room (&frchain_now->frch_obstack); | |
252b5132 RH |
302 | } |
303 | \f | |
304 | /* Make an alignment frag. The size of this frag will be adjusted to | |
305 | force the next frag to have the appropriate alignment. ALIGNMENT | |
306 | is the power of two to which to align. FILL_CHARACTER is the | |
307 | character to use to fill in any bytes which are skipped. MAX is | |
308 | the maximum number of characters to skip when doing the alignment, | |
309 | or 0 if there is no maximum. */ | |
310 | ||
29f8404c | 311 | void |
dd625418 | 312 | frag_align (int alignment, int fill_character, int max) |
252b5132 RH |
313 | { |
314 | if (now_seg == absolute_section) | |
315 | { | |
316 | addressT new_off; | |
65e68b04 | 317 | addressT mask; |
252b5132 | 318 | |
29f8404c KH |
319 | mask = (~(addressT) 0) << alignment; |
320 | new_off = (abs_section_offset + ~mask) & mask; | |
252b5132 RH |
321 | if (max == 0 || new_off - abs_section_offset <= (addressT) max) |
322 | abs_section_offset = new_off; | |
323 | } | |
324 | else | |
325 | { | |
326 | char *p; | |
327 | ||
328 | p = frag_var (rs_align, 1, 1, (relax_substateT) max, | |
329 | (symbolS *) 0, (offsetT) alignment, (char *) 0); | |
330 | *p = fill_character; | |
331 | } | |
332 | } | |
333 | ||
334 | /* Make an alignment frag like frag_align, but fill with a repeating | |
335 | pattern rather than a single byte. ALIGNMENT is the power of two | |
336 | to which to align. FILL_PATTERN is the fill pattern to repeat in | |
337 | the bytes which are skipped. N_FILL is the number of bytes in | |
338 | FILL_PATTERN. MAX is the maximum number of characters to skip when | |
339 | doing the alignment, or 0 if there is no maximum. */ | |
340 | ||
29f8404c | 341 | void |
dd625418 | 342 | frag_align_pattern (int alignment, const char *fill_pattern, |
e57e6ddc | 343 | size_t n_fill, int max) |
252b5132 RH |
344 | { |
345 | char *p; | |
346 | ||
347 | p = frag_var (rs_align, n_fill, n_fill, (relax_substateT) max, | |
348 | (symbolS *) 0, (offsetT) alignment, (char *) 0); | |
349 | memcpy (p, fill_pattern, n_fill); | |
350 | } | |
351 | ||
0a9ef439 RH |
352 | /* The NOP_OPCODE is for the alignment fill value. Fill it with a nop |
353 | instruction so that the disassembler does not choke on it. */ | |
354 | #ifndef NOP_OPCODE | |
355 | #define NOP_OPCODE 0x00 | |
356 | #endif | |
357 | ||
358 | /* Use this to restrict the amount of memory allocated for representing | |
359 | the alignment code. Needs to be large enough to hold any fixed sized | |
360 | prologue plus the replicating portion. */ | |
361 | #ifndef MAX_MEM_FOR_RS_ALIGN_CODE | |
362 | /* Assume that if HANDLE_ALIGN is not defined then no special action | |
363 | is required to code fill, which means that we get just repeat the | |
364 | one NOP_OPCODE byte. */ | |
365 | # ifndef HANDLE_ALIGN | |
366 | # define MAX_MEM_FOR_RS_ALIGN_CODE 1 | |
367 | # else | |
368 | # define MAX_MEM_FOR_RS_ALIGN_CODE ((1 << alignment) - 1) | |
369 | # endif | |
370 | #endif | |
371 | ||
372 | void | |
dd625418 | 373 | frag_align_code (int alignment, int max) |
0a9ef439 RH |
374 | { |
375 | char *p; | |
376 | ||
377 | p = frag_var (rs_align_code, MAX_MEM_FOR_RS_ALIGN_CODE, 1, | |
378 | (relax_substateT) max, (symbolS *) 0, | |
379 | (offsetT) alignment, (char *) 0); | |
380 | *p = NOP_OPCODE; | |
381 | } | |
382 | ||
252b5132 | 383 | addressT |
dd625418 | 384 | frag_now_fix_octets (void) |
252b5132 RH |
385 | { |
386 | if (now_seg == absolute_section) | |
387 | return abs_section_offset; | |
bea9907b | 388 | |
29f8404c KH |
389 | return ((char *) obstack_next_free (&frchain_now->frch_obstack) |
390 | - frag_now->fr_literal); | |
bea9907b TW |
391 | } |
392 | ||
393 | addressT | |
dd625418 | 394 | frag_now_fix (void) |
bea9907b | 395 | { |
29f8404c | 396 | return frag_now_fix_octets () / OCTETS_PER_BYTE; |
252b5132 RH |
397 | } |
398 | ||
399 | void | |
dd625418 | 400 | frag_append_1_char (int datum) |
252b5132 | 401 | { |
e85ca5bb | 402 | frag_alloc_check (&frchain_now->frch_obstack); |
252b5132 RH |
403 | if (obstack_room (&frchain_now->frch_obstack) <= 1) |
404 | { | |
405 | frag_wane (frag_now); | |
406 | frag_new (0); | |
407 | } | |
408 | obstack_1grow (&frchain_now->frch_obstack, datum); | |
409 | } | |
99630778 AM |
410 | |
411 | /* Return TRUE if FRAG1 and FRAG2 have a fixed relationship between | |
412 | their start addresses. Set OFFSET to the difference in address | |
413 | not already accounted for in the frag FR_ADDRESS. */ | |
414 | ||
415 | bfd_boolean | |
08ea7020 | 416 | frag_offset_fixed_p (const fragS *frag1, const fragS *frag2, offsetT *offset) |
99630778 | 417 | { |
6cbe03fb | 418 | const fragS *frag; |
08ea7020 | 419 | offsetT off; |
99630778 AM |
420 | |
421 | /* Start with offset initialised to difference between the two frags. | |
422 | Prior to assigning frag addresses this will be zero. */ | |
423 | off = frag1->fr_address - frag2->fr_address; | |
424 | if (frag1 == frag2) | |
425 | { | |
426 | *offset = off; | |
427 | return TRUE; | |
428 | } | |
429 | ||
430 | /* Maybe frag2 is after frag1. */ | |
431 | frag = frag1; | |
432 | while (frag->fr_type == rs_fill) | |
433 | { | |
434 | off += frag->fr_fix + frag->fr_offset * frag->fr_var; | |
435 | frag = frag->fr_next; | |
436 | if (frag == NULL) | |
437 | break; | |
438 | if (frag == frag2) | |
439 | { | |
440 | *offset = off; | |
441 | return TRUE; | |
442 | } | |
443 | } | |
444 | ||
445 | /* Maybe frag1 is after frag2. */ | |
ec651a3b | 446 | off = frag1->fr_address - frag2->fr_address; |
99630778 AM |
447 | frag = frag2; |
448 | while (frag->fr_type == rs_fill) | |
449 | { | |
450 | off -= frag->fr_fix + frag->fr_offset * frag->fr_var; | |
451 | frag = frag->fr_next; | |
452 | if (frag == NULL) | |
453 | break; | |
454 | if (frag == frag1) | |
455 | { | |
456 | *offset = off; | |
457 | return TRUE; | |
458 | } | |
459 | } | |
460 | ||
461 | return FALSE; | |
462 | } |