bfd/
[binutils.git] / gas / cgen.c
blob178402af27bc8a1d4c8e67eff739fe7d048a3b18
1 /* GAS interface for targets using CGEN: Cpu tools GENerator.
2 Copyright 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
3 2006, 2007 Free Software Foundation, Inc.
5 This file is part of GAS, the GNU Assembler.
7 GAS is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3, or (at your option)
10 any later version.
12 GAS is distributed in the hope that it will be useful, but WITHOUT
13 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
14 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
15 License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GAS; see the file COPYING. If not, write to the Free Software
19 Foundation, 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA. */
21 #include <setjmp.h>
22 #include "as.h"
23 #include "symcat.h"
24 #include "cgen-desc.h"
25 #include "subsegs.h"
26 #include "cgen.h"
27 #include "dwarf2dbg.h"
29 #include "symbols.h"
30 #include "struc-symbol.h"
32 #ifdef OBJ_COMPLEX_RELC
33 static expressionS * make_right_shifted_expr
34 (expressionS *, const int, const int);
36 static unsigned long gas_cgen_encode_addend
37 (const unsigned long, const unsigned long, const unsigned long, \
38 const unsigned long, const unsigned long, const unsigned long, \
39 const unsigned long);
41 static char * weak_operand_overflow_check
42 (const expressionS *, const CGEN_OPERAND *);
44 static void queue_fixup_recursively
45 (const int, const int, expressionS *, \
46 const CGEN_MAYBE_MULTI_IFLD *, const int, const int);
48 static int rightshift = 0;
49 #endif
50 static void queue_fixup (int, int, expressionS *);
52 /* Opcode table descriptor, must be set by md_begin. */
54 CGEN_CPU_DESC gas_cgen_cpu_desc;
56 /* Callback to insert a register into the symbol table.
57 A target may choose to let GAS parse the registers.
58 ??? Not currently used. */
60 void
61 cgen_asm_record_register (name, number)
62 char *name;
63 int number;
65 /* Use symbol_create here instead of symbol_new so we don't try to
66 output registers into the object file's symbol table. */
67 symbol_table_insert (symbol_create (name, reg_section,
68 number, &zero_address_frag));
71 /* We need to keep a list of fixups. We can't simply generate them as
72 we go, because that would require us to first create the frag, and
73 that would screw up references to ``.''.
75 This is used by cpu's with simple operands. It keeps knowledge of what
76 an `expressionS' is and what a `fixup' is out of CGEN which for the time
77 being is preferable.
79 OPINDEX is the index in the operand table.
80 OPINFO is something the caller chooses to help in reloc determination. */
82 struct fixup
84 int opindex;
85 int opinfo;
86 expressionS exp;
87 struct cgen_maybe_multi_ifield * field;
88 int msb_field_p;
91 static struct fixup fixups[GAS_CGEN_MAX_FIXUPS];
92 static int num_fixups;
94 /* Prepare to parse an instruction.
95 ??? May wish to make this static and delete calls in md_assemble. */
97 void
98 gas_cgen_init_parse ()
100 num_fixups = 0;
103 /* Queue a fixup. */
105 static void
106 queue_fixup (opindex, opinfo, expP)
107 int opindex;
108 int opinfo;
109 expressionS * expP;
111 /* We need to generate a fixup for this expression. */
112 if (num_fixups >= GAS_CGEN_MAX_FIXUPS)
113 as_fatal (_("too many fixups"));
114 fixups[num_fixups].exp = *expP;
115 fixups[num_fixups].opindex = opindex;
116 fixups[num_fixups].opinfo = opinfo;
117 ++ num_fixups;
120 /* The following functions allow fixup chains to be stored, retrieved,
121 and swapped. They are a generalization of a pre-existing scheme
122 for storing, restoring and swapping fixup chains that was used by
123 the m32r port. The functionality is essentially the same, only
124 instead of only being able to store a single fixup chain, an entire
125 array of fixup chains can be stored. It is the user's responsibility
126 to keep track of how many fixup chains have been stored and which
127 elements of the array they are in.
129 The algorithms used are the same as in the old scheme. Other than the
130 "array-ness" of the whole thing, the functionality is identical to the
131 old scheme.
133 gas_cgen_initialize_saved_fixups_array():
134 Sets num_fixups_in_chain to 0 for each element. Call this from
135 md_begin() if you plan to use these functions and you want the
136 fixup count in each element to be set to 0 initially. This is
137 not necessary, but it's included just in case. It performs
138 the same function for each element in the array of fixup chains
139 that gas_init_parse() performs for the current fixups.
141 gas_cgen_save_fixups (element):
142 element - element number of the array you wish to store the fixups
143 to. No mechanism is built in for tracking what element
144 was last stored to.
146 gas_cgen_restore_fixups (element):
147 element - element number of the array you wish to restore the fixups
148 from.
150 gas_cgen_swap_fixups(int element):
151 element - swap the current fixups with those in this element number.
154 struct saved_fixups
156 struct fixup fixup_chain[GAS_CGEN_MAX_FIXUPS];
157 int num_fixups_in_chain;
160 static struct saved_fixups stored_fixups[MAX_SAVED_FIXUP_CHAINS];
162 void
163 gas_cgen_initialize_saved_fixups_array ()
165 int i = 0;
167 while (i < MAX_SAVED_FIXUP_CHAINS)
168 stored_fixups[i++].num_fixups_in_chain = 0;
171 void
172 gas_cgen_save_fixups (i)
173 int i;
175 if (i < 0 || i >= MAX_SAVED_FIXUP_CHAINS)
177 as_fatal ("index into stored_fixups[] out of bounds");
178 return;
181 stored_fixups[i].num_fixups_in_chain = num_fixups;
182 memcpy (stored_fixups[i].fixup_chain, fixups,
183 sizeof (fixups[0]) * num_fixups);
184 num_fixups = 0;
187 void
188 gas_cgen_restore_fixups (i)
189 int i;
191 if (i < 0 || i >= MAX_SAVED_FIXUP_CHAINS)
193 as_fatal ("index into stored_fixups[] out of bounds");
194 return;
197 num_fixups = stored_fixups[i].num_fixups_in_chain;
198 memcpy (fixups, stored_fixups[i].fixup_chain,
199 (sizeof (stored_fixups[i].fixup_chain[0])) * num_fixups);
200 stored_fixups[i].num_fixups_in_chain = 0;
203 void
204 gas_cgen_swap_fixups (i)
205 int i;
207 if (i < 0 || i >= MAX_SAVED_FIXUP_CHAINS)
209 as_fatal ("index into stored_fixups[] out of bounds");
210 return;
213 if (num_fixups == 0)
214 gas_cgen_restore_fixups (i);
216 else if (stored_fixups[i].num_fixups_in_chain == 0)
217 gas_cgen_save_fixups (i);
219 else
221 int tmp;
222 struct fixup tmp_fixup;
224 tmp = stored_fixups[i].num_fixups_in_chain;
225 stored_fixups[i].num_fixups_in_chain = num_fixups;
226 num_fixups = tmp;
228 for (tmp = GAS_CGEN_MAX_FIXUPS; tmp--;)
230 tmp_fixup = stored_fixups[i].fixup_chain [tmp];
231 stored_fixups[i].fixup_chain[tmp] = fixups [tmp];
232 fixups [tmp] = tmp_fixup;
237 /* Default routine to record a fixup.
238 This is a cover function to fix_new.
239 It exists because we record INSN with the fixup.
241 FRAG and WHERE are their respective arguments to fix_new_exp.
242 LENGTH is in bits.
243 OPINFO is something the caller chooses to help in reloc determination.
245 At this point we do not use a bfd_reloc_code_real_type for
246 operands residing in the insn, but instead just use the
247 operand index. This lets us easily handle fixups for any
248 operand type. We pick a BFD reloc type in md_apply_fix. */
250 fixS *
251 gas_cgen_record_fixup (frag, where, insn, length, operand, opinfo, symbol, offset)
252 fragS * frag;
253 int where;
254 const CGEN_INSN * insn;
255 int length;
256 const CGEN_OPERAND * operand;
257 int opinfo;
258 symbolS * symbol;
259 offsetT offset;
261 fixS *fixP;
263 /* It may seem strange to use operand->attrs and not insn->attrs here,
264 but it is the operand that has a pc relative relocation. */
265 fixP = fix_new (frag, where, length / 8, symbol, offset,
266 CGEN_OPERAND_ATTR_VALUE (operand, CGEN_OPERAND_PCREL_ADDR),
267 (bfd_reloc_code_real_type)
268 ((int) BFD_RELOC_UNUSED
269 + (int) operand->type));
270 fixP->fx_cgen.insn = insn;
271 fixP->fx_cgen.opinfo = opinfo;
272 fixP->fx_cgen.field = NULL;
273 fixP->fx_cgen.msb_field_p = 0;
275 return fixP;
278 /* Default routine to record a fixup given an expression.
279 This is a cover function to fix_new_exp.
280 It exists because we record INSN with the fixup.
282 FRAG and WHERE are their respective arguments to fix_new_exp.
283 LENGTH is in bits.
284 OPINFO is something the caller chooses to help in reloc determination.
286 At this point we do not use a bfd_reloc_code_real_type for
287 operands residing in the insn, but instead just use the
288 operand index. This lets us easily handle fixups for any
289 operand type. We pick a BFD reloc type in md_apply_fix. */
291 fixS *
292 gas_cgen_record_fixup_exp (frag, where, insn, length, operand, opinfo, exp)
293 fragS * frag;
294 int where;
295 const CGEN_INSN * insn;
296 int length;
297 const CGEN_OPERAND * operand;
298 int opinfo;
299 expressionS * exp;
301 fixS *fixP;
303 /* It may seem strange to use operand->attrs and not insn->attrs here,
304 but it is the operand that has a pc relative relocation. */
305 fixP = fix_new_exp (frag, where, length / 8, exp,
306 CGEN_OPERAND_ATTR_VALUE (operand, CGEN_OPERAND_PCREL_ADDR),
307 (bfd_reloc_code_real_type)
308 ((int) BFD_RELOC_UNUSED
309 + (int) operand->type));
310 fixP->fx_cgen.insn = insn;
311 fixP->fx_cgen.opinfo = opinfo;
312 fixP->fx_cgen.field = NULL;
313 fixP->fx_cgen.msb_field_p = 0;
315 return fixP;
318 #ifdef OBJ_COMPLEX_RELC
319 static symbolS *
320 expr_build_binary (operatorT op, symbolS * s1, symbolS * s2)
322 expressionS e;
324 e.X_op = op;
325 e.X_add_symbol = s1;
326 e.X_op_symbol = s2;
327 e.X_add_number = 0;
328 return make_expr_symbol (& e);
330 #endif
332 /* Used for communication between the next two procedures. */
333 static jmp_buf expr_jmp_buf;
334 static int expr_jmp_buf_p;
336 /* Callback for cgen interface. Parse the expression at *STRP.
337 The result is an error message or NULL for success (in which case
338 *STRP is advanced past the parsed text).
339 WANT is an indication of what the caller is looking for.
340 If WANT == CGEN_ASM_PARSE_INIT the caller is beginning to try to match
341 a table entry with the insn, reset the queued fixups counter.
342 An enum cgen_parse_operand_result is stored in RESULTP.
343 OPINDEX is the operand's table entry index.
344 OPINFO is something the caller chooses to help in reloc determination.
345 The resulting value is stored in VALUEP. */
347 const char *
348 gas_cgen_parse_operand (cd, want, strP, opindex, opinfo, resultP, valueP)
350 #ifdef OBJ_COMPLEX_RELC
351 CGEN_CPU_DESC cd;
352 #else
353 CGEN_CPU_DESC cd ATTRIBUTE_UNUSED;
354 #endif
355 enum cgen_parse_operand_type want;
356 const char **strP;
357 int opindex;
358 int opinfo;
359 enum cgen_parse_operand_result *resultP;
360 bfd_vma *valueP;
362 #ifdef __STDC__
363 /* These are volatile to survive the setjmp. */
364 char * volatile hold;
365 enum cgen_parse_operand_result * volatile resultP_1;
366 volatile int opinfo_1;
367 #else
368 static char *hold;
369 static enum cgen_parse_operand_result *resultP_1;
370 int opinfo_1;
371 #endif
372 const char *errmsg;
373 expressionS exp;
375 #ifdef OBJ_COMPLEX_RELC
376 volatile int signed_p = 0;
377 symbolS * stmp = NULL;
378 bfd_reloc_code_real_type reloc_type;
379 const CGEN_OPERAND * operand;
380 fixS dummy_fixup;
381 #endif
382 if (want == CGEN_PARSE_OPERAND_INIT)
384 gas_cgen_init_parse ();
385 return NULL;
388 resultP_1 = resultP;
389 hold = input_line_pointer;
390 input_line_pointer = (char *) *strP;
391 opinfo_1 = opinfo;
393 /* We rely on md_operand to longjmp back to us.
394 This is done via gas_cgen_md_operand. */
395 if (setjmp (expr_jmp_buf) != 0)
397 expr_jmp_buf_p = 0;
398 input_line_pointer = (char *) hold;
399 *resultP_1 = CGEN_PARSE_OPERAND_RESULT_ERROR;
400 return _("illegal operand");
403 expr_jmp_buf_p = 1;
404 expression (&exp);
405 expr_jmp_buf_p = 0;
406 errmsg = NULL;
408 *strP = input_line_pointer;
409 input_line_pointer = hold;
411 #ifdef TC_CGEN_PARSE_FIX_EXP
412 opinfo_1 = TC_CGEN_PARSE_FIX_EXP (opinfo_1, & exp);
413 #endif
415 /* FIXME: Need to check `want'. */
417 switch (exp.X_op)
419 case O_illegal:
420 errmsg = _("illegal operand");
421 *resultP = CGEN_PARSE_OPERAND_RESULT_ERROR;
422 break;
423 case O_absent:
424 errmsg = _("missing operand");
425 *resultP = CGEN_PARSE_OPERAND_RESULT_ERROR;
426 break;
427 case O_constant:
428 if (want == CGEN_PARSE_OPERAND_SYMBOLIC)
429 goto de_fault;
430 *valueP = exp.X_add_number;
431 *resultP = CGEN_PARSE_OPERAND_RESULT_NUMBER;
432 break;
433 case O_register:
434 *valueP = exp.X_add_number;
435 *resultP = CGEN_PARSE_OPERAND_RESULT_REGISTER;
436 break;
437 de_fault:
438 default:
439 #ifdef OBJ_COMPLEX_RELC
440 /* Look up operand, check to see if there's an obvious
441 overflow (this helps disambiguate some insn parses). */
442 operand = cgen_operand_lookup_by_num (cd, opindex);
443 errmsg = weak_operand_overflow_check (& exp, operand);
445 if (! errmsg)
447 /* Fragment the expression as necessary, and queue a reloc. */
448 memset (& dummy_fixup, 0, sizeof (fixS));
450 reloc_type = md_cgen_lookup_reloc (0, operand, & dummy_fixup);
452 if (exp.X_op == O_symbol
453 && reloc_type == BFD_RELOC_RELC
454 && exp.X_add_symbol->sy_value.X_op == O_constant
455 && exp.X_add_symbol->bsym->section != expr_section
456 && exp.X_add_symbol->bsym->section != absolute_section
457 && exp.X_add_symbol->bsym->section != undefined_section)
459 /* Local labels will have been (eagerly) turned into constants
460 by now, due to the inappropriately deep insight of the
461 expression parser. Unfortunately make_expr_symbol
462 prematurely dives into the symbol evaluator, and in this
463 case it gets a bad answer, so we manually create the
464 expression symbol we want here. */
465 stmp = symbol_create (FAKE_LABEL_NAME, expr_section, 0,
466 & zero_address_frag);
467 symbol_set_value_expression (stmp, & exp);
469 else
470 stmp = make_expr_symbol (& exp);
472 /* If this is a pc-relative RELC operand, we
473 need to subtract "." from the expression. */
474 if (reloc_type == BFD_RELOC_RELC
475 && CGEN_OPERAND_ATTR_VALUE (operand, CGEN_OPERAND_PCREL_ADDR))
476 stmp = expr_build_binary (O_subtract, stmp, expr_build_dot ());
478 /* FIXME: this is not a perfect heuristic for figuring out
479 whether an operand is signed: it only works when the operand
480 is an immediate. it's not terribly likely that any other
481 values will be signed relocs, but it's possible. */
482 if (operand && (operand->hw_type == HW_H_SINT))
483 signed_p = 1;
485 if (stmp->bsym && (stmp->bsym->section == expr_section))
487 if (signed_p)
488 stmp->bsym->flags |= BSF_SRELC;
489 else
490 stmp->bsym->flags |= BSF_RELC;
493 /* Now package it all up for the fixup emitter. */
494 exp.X_op = O_symbol;
495 exp.X_op_symbol = 0;
496 exp.X_add_symbol = stmp;
497 exp.X_add_number = 0;
499 /* Re-init rightshift quantity, just in case. */
500 rightshift = operand->length;
501 queue_fixup_recursively (opindex, opinfo_1, & exp,
502 (reloc_type == BFD_RELOC_RELC) ?
503 & (operand->index_fields) : 0,
504 signed_p, -1);
506 * resultP = errmsg
507 ? CGEN_PARSE_OPERAND_RESULT_ERROR
508 : CGEN_PARSE_OPERAND_RESULT_QUEUED;
509 *valueP = 0;
510 #else
511 queue_fixup (opindex, opinfo_1, &exp);
512 *valueP = 0;
513 *resultP = CGEN_PARSE_OPERAND_RESULT_QUEUED;
514 #endif
515 break;
518 return errmsg;
521 /* md_operand handler to catch unrecognized expressions and halt the
522 parsing process so the next entry can be tried.
524 ??? This could be done differently by adding code to `expression'. */
526 void
527 gas_cgen_md_operand (expressionP)
528 expressionS *expressionP ATTRIBUTE_UNUSED;
530 /* Don't longjmp if we're not called from within cgen_parse_operand(). */
531 if (expr_jmp_buf_p)
532 longjmp (expr_jmp_buf, 1);
535 /* Finish assembling instruction INSN.
536 BUF contains what we've built up so far.
537 LENGTH is the size of the insn in bits.
538 RELAX_P is non-zero if relaxable insns should be emitted as such.
539 Otherwise they're emitted in non-relaxable forms.
540 The "result" is stored in RESULT if non-NULL. */
542 void
543 gas_cgen_finish_insn (insn, buf, length, relax_p, result)
544 const CGEN_INSN *insn;
545 CGEN_INSN_BYTES_PTR buf;
546 unsigned int length;
547 int relax_p;
548 finished_insnS *result;
550 int i;
551 int relax_operand;
552 char *f;
553 unsigned int byte_len = length / 8;
555 /* ??? Target foo issues various warnings here, so one might want to provide
556 a hook here. However, our caller is defined in tc-foo.c so there
557 shouldn't be a need for a hook. */
559 /* Write out the instruction.
560 It is important to fetch enough space in one call to `frag_more'.
561 We use (f - frag_now->fr_literal) to compute where we are and we
562 don't want frag_now to change between calls.
564 Relaxable instructions: We need to ensure we allocate enough
565 space for the largest insn. */
567 if (CGEN_INSN_ATTR_VALUE (insn, CGEN_INSN_RELAXED))
568 /* These currently shouldn't get here. */
569 abort ();
571 /* Is there a relaxable insn with the relaxable operand needing a fixup? */
573 relax_operand = -1;
574 if (relax_p && CGEN_INSN_ATTR_VALUE (insn, CGEN_INSN_RELAXABLE))
576 /* Scan the fixups for the operand affected by relaxing
577 (i.e. the branch address). */
579 for (i = 0; i < num_fixups; ++i)
581 if (CGEN_OPERAND_ATTR_VALUE (cgen_operand_lookup_by_num (gas_cgen_cpu_desc, fixups[i].opindex),
582 CGEN_OPERAND_RELAX))
584 relax_operand = i;
585 break;
590 if (relax_operand != -1)
592 int max_len;
593 fragS *old_frag;
594 expressionS *exp;
595 symbolS *sym;
596 offsetT off;
598 #ifdef TC_CGEN_MAX_RELAX
599 max_len = TC_CGEN_MAX_RELAX (insn, byte_len);
600 #else
601 max_len = CGEN_MAX_INSN_SIZE;
602 #endif
603 /* Ensure variable part and fixed part are in same fragment. */
604 /* FIXME: Having to do this seems like a hack. */
605 frag_grow (max_len);
607 /* Allocate space for the fixed part. */
608 f = frag_more (byte_len);
610 /* Create a relaxable fragment for this instruction. */
611 old_frag = frag_now;
613 exp = &fixups[relax_operand].exp;
614 sym = exp->X_add_symbol;
615 off = exp->X_add_number;
616 if (exp->X_op != O_constant && exp->X_op != O_symbol)
618 /* Handle complex expressions. */
619 sym = make_expr_symbol (exp);
620 off = 0;
623 frag_var (rs_machine_dependent,
624 max_len - byte_len /* max chars */,
625 0 /* variable part already allocated */,
626 /* FIXME: When we machine generate the relax table,
627 machine generate a macro to compute subtype. */
628 1 /* subtype */,
629 sym,
630 off,
633 /* Record the operand number with the fragment so md_convert_frag
634 can use gas_cgen_md_record_fixup to record the appropriate reloc. */
635 old_frag->fr_cgen.insn = insn;
636 old_frag->fr_cgen.opindex = fixups[relax_operand].opindex;
637 old_frag->fr_cgen.opinfo = fixups[relax_operand].opinfo;
638 if (result)
639 result->frag = old_frag;
641 else
643 f = frag_more (byte_len);
644 if (result)
645 result->frag = frag_now;
648 /* If we're recording insns as numbers (rather than a string of bytes),
649 target byte order handling is deferred until now. */
650 #if CGEN_INT_INSN_P
651 cgen_put_insn_value (gas_cgen_cpu_desc, (unsigned char *) f, length, *buf);
652 #else
653 memcpy (f, buf, byte_len);
654 #endif
656 /* Emit DWARF2 debugging information. */
657 dwarf2_emit_insn (byte_len);
659 /* Create any fixups. */
660 for (i = 0; i < num_fixups; ++i)
662 fixS *fixP;
663 const CGEN_OPERAND *operand =
664 cgen_operand_lookup_by_num (gas_cgen_cpu_desc, fixups[i].opindex);
666 /* Don't create fixups for these. That's done during relaxation.
667 We don't need to test for CGEN_INSN_RELAXED as they can't get here
668 (see above). */
669 if (relax_p
670 && CGEN_INSN_ATTR_VALUE (insn, CGEN_INSN_RELAXABLE)
671 && CGEN_OPERAND_ATTR_VALUE (operand, CGEN_OPERAND_RELAX))
672 continue;
674 #ifndef md_cgen_record_fixup_exp
675 #define md_cgen_record_fixup_exp gas_cgen_record_fixup_exp
676 #endif
678 fixP = md_cgen_record_fixup_exp (frag_now, f - frag_now->fr_literal,
679 insn, length, operand,
680 fixups[i].opinfo,
681 &fixups[i].exp);
682 fixP->fx_cgen.field = fixups[i].field;
683 fixP->fx_cgen.msb_field_p = fixups[i].msb_field_p;
684 if (result)
685 result->fixups[i] = fixP;
688 if (result)
690 result->num_fixups = num_fixups;
691 result->addr = f;
695 #ifdef OBJ_COMPLEX_RELC
696 /* Queue many fixups, recursively. If the field is a multi-ifield,
697 repeatedly queue its sub-parts, right shifted to fit into the field (we
698 assume here multi-fields represent a left-to-right, MSB0-LSB0
699 reading). */
701 static void
702 queue_fixup_recursively (const int opindex,
703 const int opinfo,
704 expressionS * expP,
705 const CGEN_MAYBE_MULTI_IFLD * field,
706 const int signed_p,
707 const int part_of_multi)
709 if (field && field->count)
711 int i;
713 for (i = 0; i < field->count; ++ i)
714 queue_fixup_recursively (opindex, opinfo, expP,
715 & (field->val.multi[i]), signed_p, i);
717 else
719 expressionS * new_exp = expP;
721 #ifdef DEBUG
722 printf ("queueing fixup for field %s\n",
723 (field ? field->val.leaf->name : "??"));
724 print_symbol_value (expP->X_add_symbol);
725 #endif
726 if (field && part_of_multi != -1)
728 rightshift -= field->val.leaf->length;
730 /* Shift reloc value by number of bits remaining after this
731 field. */
732 if (rightshift)
733 new_exp = make_right_shifted_expr (expP, rightshift, signed_p);
736 /* Truncate reloc values to length, *after* leftmost one. */
737 fixups[num_fixups].msb_field_p = (part_of_multi <= 0);
738 fixups[num_fixups].field = (CGEN_MAYBE_MULTI_IFLD *) field;
740 queue_fixup (opindex, opinfo, new_exp);
744 /* Encode the self-describing RELC reloc format's addend. */
746 static unsigned long
747 gas_cgen_encode_addend (const unsigned long start, /* in bits */
748 const unsigned long len, /* in bits */
749 const unsigned long oplen, /* in bits */
750 const unsigned long wordsz, /* in bytes */
751 const unsigned long chunksz, /* in bytes */
752 const unsigned long signed_p,
753 const unsigned long trunc_p)
755 unsigned long res = 0L;
757 res |= start & 0x3F;
758 res |= (oplen & 0x3F) << 6;
759 res |= (len & 0x3F) << 12;
760 res |= (wordsz & 0xF) << 18;
761 res |= (chunksz & 0xF) << 22;
762 res |= (CGEN_INSN_LSB0_P ? 1 : 0) << 27;
763 res |= signed_p << 28;
764 res |= trunc_p << 29;
766 return res;
769 /* Purpose: make a weak check that the expression doesn't overflow the
770 operand it's to be inserted into.
772 Rationale: some insns used to use %operators to disambiguate during a
773 parse. when these %operators are translated to expressions by the macro
774 expander, the ambiguity returns. we attempt to disambiguate by field
775 size.
777 Method: check to see if the expression's top node is an O_and operator,
778 and the mask is larger than the operand length. This would be an
779 overflow, so signal it by returning an error string. Any other case is
780 ambiguous, so we assume it's OK and return NULL. */
782 static char *
783 weak_operand_overflow_check (const expressionS * exp,
784 const CGEN_OPERAND * operand)
786 const unsigned long len = operand->length;
787 unsigned long mask;
788 unsigned long opmask = (((1L << (len - 1)) - 1) << 1) | 1;
790 if (!exp)
791 return NULL;
793 if (exp->X_op != O_bit_and)
795 /* Check for implicit overflow flag. */
796 if (CGEN_OPERAND_ATTR_VALUE
797 (operand, CGEN_OPERAND_RELOC_IMPLIES_OVERFLOW))
798 return _("a reloc on this operand implies an overflow");
799 return NULL;
802 mask = exp->X_add_number;
804 if (exp->X_add_symbol &&
805 exp->X_add_symbol->sy_value.X_op == O_constant)
806 mask |= exp->X_add_symbol->sy_value.X_add_number;
808 if (exp->X_op_symbol &&
809 exp->X_op_symbol->sy_value.X_op == O_constant)
810 mask |= exp->X_op_symbol->sy_value.X_add_number;
812 /* Want to know if mask covers more bits than opmask.
813 this is the same as asking if mask has any bits not in opmask,
814 or whether (mask & ~opmask) is nonzero. */
815 if (mask && (mask & ~opmask))
817 #ifdef DEBUG
818 printf ("overflow: (mask = %8.8x, ~opmask = %8.8x, AND = %8.8x)\n",
819 mask, ~opmask, (mask & ~opmask));
820 #endif
821 return _("operand mask overflow");
824 return NULL;
828 static expressionS *
829 make_right_shifted_expr (expressionS * exp,
830 const int amount,
831 const int signed_p)
833 symbolS * stmp = 0;
834 expressionS * new_exp;
836 stmp = expr_build_binary (O_right_shift,
837 make_expr_symbol (exp),
838 expr_build_uconstant (amount));
840 if (signed_p)
841 stmp->bsym->flags |= BSF_SRELC;
842 else
843 stmp->bsym->flags |= BSF_RELC;
845 /* Then wrap that in a "symbol expr" for good measure. */
846 new_exp = xmalloc (sizeof (expressionS));
847 memset (new_exp, 0, sizeof (expressionS));
848 new_exp->X_op = O_symbol;
849 new_exp->X_op_symbol = 0;
850 new_exp->X_add_symbol = stmp;
851 new_exp->X_add_number = 0;
853 return new_exp;
855 #endif
856 /* Apply a fixup to the object code. This is called for all the
857 fixups we generated by the call to fix_new_exp, above. In the call
858 above we used a reloc code which was the largest legal reloc code
859 plus the operand index. Here we undo that to recover the operand
860 index. At this point all symbol values should be fully resolved,
861 and we attempt to completely resolve the reloc. If we can not do
862 that, we determine the correct reloc code and put it back in the fixup. */
864 /* FIXME: This function handles some of the fixups and bfd_install_relocation
865 handles the rest. bfd_install_relocation (or some other bfd function)
866 should handle them all. */
868 void
869 gas_cgen_md_apply_fix (fixP, valP, seg)
870 fixS * fixP;
871 valueT * valP;
872 segT seg ATTRIBUTE_UNUSED;
874 char *where = fixP->fx_frag->fr_literal + fixP->fx_where;
875 valueT value = * valP;
876 /* Canonical name, since used a lot. */
877 CGEN_CPU_DESC cd = gas_cgen_cpu_desc;
879 if (fixP->fx_addsy == (symbolS *) NULL)
880 fixP->fx_done = 1;
882 /* We don't actually support subtracting a symbol. */
883 if (fixP->fx_subsy != (symbolS *) NULL)
884 as_bad_where (fixP->fx_file, fixP->fx_line, _("expression too complex"));
886 if ((int) fixP->fx_r_type >= (int) BFD_RELOC_UNUSED)
888 int opindex = (int) fixP->fx_r_type - (int) BFD_RELOC_UNUSED;
889 const CGEN_OPERAND *operand = cgen_operand_lookup_by_num (cd, opindex);
890 const char *errmsg;
891 bfd_reloc_code_real_type reloc_type;
892 CGEN_FIELDS *fields = alloca (CGEN_CPU_SIZEOF_FIELDS (cd));
893 const CGEN_INSN *insn = fixP->fx_cgen.insn;
894 int start;
895 int length;
896 int signed_p = 0;
898 if (fixP->fx_cgen.field)
900 /* Use the twisty little pointer path
901 back to the ifield if it exists. */
902 start = fixP->fx_cgen.field->val.leaf->start;
903 length = fixP->fx_cgen.field->val.leaf->length;
905 else
907 /* Or the far less useful operand-size guesstimate. */
908 start = operand->start;
909 length = operand->length;
912 /* FIXME: this is not a perfect heuristic for figuring out
913 whether an operand is signed: it only works when the operand
914 is an immediate. it's not terribly likely that any other
915 values will be signed relocs, but it's possible. */
916 if (operand && (operand->hw_type == HW_H_SINT))
917 signed_p = 1;
919 /* If the reloc has been fully resolved finish the operand here. */
920 /* FIXME: This duplicates the capabilities of code in BFD. */
921 if (fixP->fx_done
922 /* FIXME: If partial_inplace isn't set bfd_install_relocation won't
923 finish the job. Testing for pcrel is a temporary hack. */
924 || fixP->fx_pcrel)
926 CGEN_CPU_SET_FIELDS_BITSIZE (cd) (fields, CGEN_INSN_BITSIZE (insn));
927 CGEN_CPU_SET_VMA_OPERAND (cd) (cd, opindex, fields, (bfd_vma) value);
929 #if CGEN_INT_INSN_P
931 CGEN_INSN_INT insn_value =
932 cgen_get_insn_value (cd, (unsigned char *) where,
933 CGEN_INSN_BITSIZE (insn));
935 /* ??? 0 is passed for `pc'. */
936 errmsg = CGEN_CPU_INSERT_OPERAND (cd) (cd, opindex, fields,
937 &insn_value, (bfd_vma) 0);
938 cgen_put_insn_value (cd, (unsigned char *) where,
939 CGEN_INSN_BITSIZE (insn), insn_value);
941 #else
942 /* ??? 0 is passed for `pc'. */
943 errmsg = CGEN_CPU_INSERT_OPERAND (cd) (cd, opindex, fields,
944 (unsigned char *) where,
945 (bfd_vma) 0);
946 #endif
947 if (errmsg)
948 as_bad_where (fixP->fx_file, fixP->fx_line, "%s", errmsg);
951 if (fixP->fx_done)
952 return;
954 /* The operand isn't fully resolved. Determine a BFD reloc value
955 based on the operand information and leave it to
956 bfd_install_relocation. Note that this doesn't work when
957 partial_inplace == false. */
959 reloc_type = md_cgen_lookup_reloc (insn, operand, fixP);
960 #ifdef OBJ_COMPLEX_RELC
961 if (reloc_type == BFD_RELOC_RELC)
963 /* Change addend to "self-describing" form,
964 for BFD to handle in the linker. */
965 value = gas_cgen_encode_addend (start, operand->length,
966 length, fixP->fx_size,
967 cd->insn_chunk_bitsize / 8,
968 signed_p,
969 ! (fixP->fx_cgen.msb_field_p));
971 #endif
973 if (reloc_type != BFD_RELOC_NONE)
974 fixP->fx_r_type = reloc_type;
975 else
977 as_bad_where (fixP->fx_file, fixP->fx_line,
978 _("unresolved expression that must be resolved"));
979 fixP->fx_done = 1;
980 return;
983 else if (fixP->fx_done)
985 /* We're finished with this fixup. Install it because
986 bfd_install_relocation won't be called to do it. */
987 switch (fixP->fx_r_type)
989 case BFD_RELOC_8:
990 md_number_to_chars (where, value, 1);
991 break;
992 case BFD_RELOC_16:
993 md_number_to_chars (where, value, 2);
994 break;
995 case BFD_RELOC_32:
996 md_number_to_chars (where, value, 4);
997 break;
998 case BFD_RELOC_64:
999 md_number_to_chars (where, value, 8);
1000 break;
1001 default:
1002 as_bad_where (fixP->fx_file, fixP->fx_line,
1003 _("internal error: can't install fix for reloc type %d (`%s')"),
1004 fixP->fx_r_type, bfd_get_reloc_code_name (fixP->fx_r_type));
1005 break;
1008 /* else
1009 bfd_install_relocation will be called to finish things up. */
1011 /* Tuck `value' away for use by tc_gen_reloc.
1012 See the comment describing fx_addnumber in write.h.
1013 This field is misnamed (or misused :-). */
1014 fixP->fx_addnumber = value;
1017 /* Translate internal representation of relocation info to BFD target format.
1019 FIXME: To what extent can we get all relevant targets to use this? */
1021 arelent *
1022 gas_cgen_tc_gen_reloc (section, fixP)
1023 asection * section ATTRIBUTE_UNUSED;
1024 fixS * fixP;
1026 arelent *reloc;
1027 reloc = (arelent *) xmalloc (sizeof (arelent));
1029 reloc->howto = bfd_reloc_type_lookup (stdoutput, fixP->fx_r_type);
1030 if (reloc->howto == (reloc_howto_type *) NULL)
1032 as_bad_where (fixP->fx_file, fixP->fx_line,
1033 _("relocation is not supported"));
1034 return NULL;
1037 assert (!fixP->fx_pcrel == !reloc->howto->pc_relative);
1039 reloc->sym_ptr_ptr = (asymbol **) xmalloc (sizeof (asymbol *));
1040 *reloc->sym_ptr_ptr = symbol_get_bfdsym (fixP->fx_addsy);
1042 /* Use fx_offset for these cases. */
1043 if (fixP->fx_r_type == BFD_RELOC_VTABLE_ENTRY
1044 || fixP->fx_r_type == BFD_RELOC_VTABLE_INHERIT)
1045 reloc->addend = fixP->fx_offset;
1046 else
1047 reloc->addend = fixP->fx_addnumber;
1049 reloc->address = fixP->fx_frag->fr_address + fixP->fx_where;
1050 return reloc;
1053 /* Perform any cgen specific initialisation.
1054 Called after gas_cgen_cpu_desc has been created. */
1056 void
1057 gas_cgen_begin ()
1059 if (flag_signed_overflow_ok)
1060 cgen_set_signed_overflow_ok (gas_cgen_cpu_desc);
1061 else
1062 cgen_clear_signed_overflow_ok (gas_cgen_cpu_desc);