1 | /* DWARF2 exception handling and frame unwind runtime interface routines. |
2 | Copyright (C) 1997-2024 Free Software Foundation, Inc. |
3 | |
4 | This file is part of the GNU C Library. |
5 | |
6 | The GNU C Library is free software; you can redistribute it and/or |
7 | modify it under the terms of the GNU Lesser General Public |
8 | License as published by the Free Software Foundation; either |
9 | version 2.1 of the License, or (at your option) any later version. |
10 | |
11 | The GNU C Library 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 GNU |
14 | Lesser General Public License for more details. |
15 | |
16 | You should have received a copy of the GNU Lesser General Public |
17 | License along with the GNU C Library; if not, see |
18 | <https://www.gnu.org/licenses/>. */ |
19 | |
20 | #ifdef _LIBC |
21 | #include <stdlib.h> |
22 | #include <string.h> |
23 | #include <error.h> |
24 | #include <libintl.h> |
25 | #include <dwarf2.h> |
26 | #include <stdio.h> |
27 | #include <unwind.h> |
28 | #include <unwind-pe.h> |
29 | #include <unwind-dw2-fde.h> |
30 | #else |
31 | #include "tconfig.h" |
32 | #include "tsystem.h" |
33 | #include "dwarf2.h" |
34 | #include "unwind.h" |
35 | #include "unwind-pe.h" |
36 | #include "unwind-dw2-fde.h" |
37 | #include "gthr.h" |
38 | #endif |
39 | |
40 | |
41 | |
42 | #ifndef STACK_GROWS_DOWNWARD |
43 | #define STACK_GROWS_DOWNWARD 0 |
44 | #else |
45 | #undef STACK_GROWS_DOWNWARD |
46 | #define STACK_GROWS_DOWNWARD 1 |
47 | #endif |
48 | |
49 | /* A target can override (perhaps for backward compatibility) how |
50 | many dwarf2 columns are unwound. */ |
51 | #ifndef DWARF_FRAME_REGISTERS |
52 | #define DWARF_FRAME_REGISTERS FIRST_PSEUDO_REGISTER |
53 | #endif |
54 | |
55 | /* Dwarf frame registers used for pre gcc 3.0 compiled glibc. */ |
56 | #ifndef PRE_GCC3_DWARF_FRAME_REGISTERS |
57 | #define PRE_GCC3_DWARF_FRAME_REGISTERS DWARF_FRAME_REGISTERS |
58 | #endif |
59 | |
60 | /* This is the register and unwind state for a particular frame. This |
61 | provides the information necessary to unwind up past a frame and return |
62 | to its caller. */ |
63 | struct _Unwind_Context |
64 | { |
65 | void *reg[DWARF_FRAME_REGISTERS+1]; |
66 | void *cfa; |
67 | void *ra; |
68 | void *lsda; |
69 | struct dwarf_eh_bases bases; |
70 | _Unwind_Word args_size; |
71 | }; |
72 | |
73 | #ifndef _LIBC |
74 | /* Byte size of every register managed by these routines. */ |
75 | static unsigned char dwarf_reg_size_table[DWARF_FRAME_REGISTERS]; |
76 | #endif |
77 | |
78 | |
79 | /* The result of interpreting the frame unwind info for a frame. |
80 | This is all symbolic at this point, as none of the values can |
81 | be resolved until the target pc is located. */ |
82 | typedef struct |
83 | { |
84 | /* Each register save state can be described in terms of a CFA slot, |
85 | another register, or a location expression. */ |
86 | struct frame_state_reg_info |
87 | { |
88 | struct { |
89 | union { |
90 | _Unwind_Word reg; |
91 | _Unwind_Sword offset; |
92 | const unsigned char *exp; |
93 | } loc; |
94 | enum { |
95 | REG_UNSAVED, |
96 | REG_SAVED_OFFSET, |
97 | REG_SAVED_REG, |
98 | REG_SAVED_EXP, |
99 | } how; |
100 | } reg[DWARF_FRAME_REGISTERS+1]; |
101 | |
102 | /* Used to implement DW_CFA_remember_state. */ |
103 | struct frame_state_reg_info *prev; |
104 | } regs; |
105 | |
106 | /* The CFA can be described in terms of a reg+offset or a |
107 | location expression. */ |
108 | _Unwind_Sword cfa_offset; |
109 | _Unwind_Word cfa_reg; |
110 | const unsigned char *cfa_exp; |
111 | enum { |
112 | CFA_UNSET, |
113 | CFA_REG_OFFSET, |
114 | CFA_EXP, |
115 | } cfa_how; |
116 | |
117 | /* The PC described by the current frame state. */ |
118 | void *pc; |
119 | |
120 | /* The information we care about from the CIE/FDE. */ |
121 | _Unwind_Personality_Fn personality; |
122 | _Unwind_Sword data_align; |
123 | _Unwind_Word code_align; |
124 | unsigned char retaddr_column; |
125 | unsigned char fde_encoding; |
126 | unsigned char lsda_encoding; |
127 | unsigned char saw_z; |
128 | void *eh_ptr; |
129 | } _Unwind_FrameState; |
130 | |
131 | /* Read unaligned data from the instruction buffer. */ |
132 | |
133 | union unaligned |
134 | { |
135 | void *p; |
136 | unsigned u2 __attribute__ ((mode (HI))); |
137 | unsigned u4 __attribute__ ((mode (SI))); |
138 | unsigned u8 __attribute__ ((mode (DI))); |
139 | signed s2 __attribute__ ((mode (HI))); |
140 | signed s4 __attribute__ ((mode (SI))); |
141 | signed s8 __attribute__ ((mode (DI))); |
142 | } __attribute__ ((packed)); |
143 | |
144 | static inline void * |
145 | read_pointer (const void *p) { const union unaligned *up = p; return up->p; } |
146 | |
147 | static inline int |
148 | read_1u (const void *p) { return *(const unsigned char *) p; } |
149 | |
150 | static inline int |
151 | read_1s (const void *p) { return *(const signed char *) p; } |
152 | |
153 | static inline int |
154 | read_2u (const void *p) { const union unaligned *up = p; return up->u2; } |
155 | |
156 | static inline int |
157 | read_2s (const void *p) { const union unaligned *up = p; return up->s2; } |
158 | |
159 | static inline unsigned int |
160 | read_4u (const void *p) { const union unaligned *up = p; return up->u4; } |
161 | |
162 | static inline int |
163 | read_4s (const void *p) { const union unaligned *up = p; return up->s4; } |
164 | |
165 | static inline unsigned long |
166 | read_8u (const void *p) { const union unaligned *up = p; return up->u8; } |
167 | |
168 | static inline unsigned long |
169 | read_8s (const void *p) { const union unaligned *up = p; return up->s8; } |
170 | |
171 | /* Get the value of register REG as saved in CONTEXT. */ |
172 | |
173 | inline _Unwind_Word |
174 | _Unwind_GetGR (struct _Unwind_Context *context, int index) |
175 | { |
176 | /* This will segfault if the register hasn't been saved. */ |
177 | return * (_Unwind_Word *) context->reg[index]; |
178 | } |
179 | |
180 | /* Overwrite the saved value for register REG in CONTEXT with VAL. */ |
181 | |
182 | inline void |
183 | _Unwind_SetGR (struct _Unwind_Context *context, int index, _Unwind_Word val) |
184 | { |
185 | * (_Unwind_Word *) context->reg[index] = val; |
186 | } |
187 | |
188 | /* Retrieve the return address for CONTEXT. */ |
189 | |
190 | inline _Unwind_Ptr |
191 | _Unwind_GetIP (struct _Unwind_Context *context) |
192 | { |
193 | return (_Unwind_Ptr) context->ra; |
194 | } |
195 | |
196 | /* Overwrite the return address for CONTEXT with VAL. */ |
197 | |
198 | inline void |
199 | _Unwind_SetIP (struct _Unwind_Context *context, _Unwind_Ptr val) |
200 | { |
201 | context->ra = (void *) val; |
202 | } |
203 | |
204 | void * |
205 | _Unwind_GetLanguageSpecificData (struct _Unwind_Context *context) |
206 | { |
207 | return context->lsda; |
208 | } |
209 | |
210 | _Unwind_Ptr |
211 | _Unwind_GetRegionStart (struct _Unwind_Context *context) |
212 | { |
213 | return (_Unwind_Ptr) context->bases.func; |
214 | } |
215 | |
216 | void * |
217 | _Unwind_FindEnclosingFunction (void *pc) |
218 | { |
219 | struct dwarf_eh_bases bases; |
220 | struct dwarf_fde *fde = _Unwind_Find_FDE (pc-1, &bases); |
221 | if (fde) |
222 | return bases.func; |
223 | else |
224 | return NULL; |
225 | } |
226 | |
227 | _Unwind_Ptr |
228 | _Unwind_GetDataRelBase (struct _Unwind_Context *context) |
229 | { |
230 | return (_Unwind_Ptr) context->bases.dbase; |
231 | } |
232 | |
233 | _Unwind_Ptr |
234 | _Unwind_GetTextRelBase (struct _Unwind_Context *context) |
235 | { |
236 | return (_Unwind_Ptr) context->bases.tbase; |
237 | } |
238 | |
239 | /* Extract any interesting information from the CIE for the translation |
240 | unit F belongs to. Return a pointer to the byte after the augmentation, |
241 | or NULL if we encountered an undecipherable augmentation. */ |
242 | |
243 | static const unsigned char * |
244 | (struct dwarf_cie *cie, struct _Unwind_Context *context, |
245 | _Unwind_FrameState *fs) |
246 | { |
247 | const unsigned char *aug = cie->augmentation; |
248 | const unsigned char *p = aug + strlen ((const char *) aug) + 1; |
249 | const unsigned char *ret = NULL; |
250 | _Unwind_Word utmp; |
251 | |
252 | /* g++ v2 "eh" has pointer immediately following augmentation string, |
253 | so it must be handled first. */ |
254 | if (aug[0] == 'e' && aug[1] == 'h') |
255 | { |
256 | fs->eh_ptr = read_pointer (p); |
257 | p += sizeof (void *); |
258 | aug += 2; |
259 | } |
260 | |
261 | /* Immediately following the augmentation are the code and |
262 | data alignment and return address column. */ |
263 | p = read_uleb128 (p, val: &fs->code_align); |
264 | p = read_sleb128 (p, val: &fs->data_align); |
265 | fs->retaddr_column = *p++; |
266 | fs->lsda_encoding = DW_EH_PE_omit; |
267 | |
268 | /* If the augmentation starts with 'z', then a uleb128 immediately |
269 | follows containing the length of the augmentation field following |
270 | the size. */ |
271 | if (*aug == 'z') |
272 | { |
273 | p = read_uleb128 (p, val: &utmp); |
274 | ret = p + utmp; |
275 | |
276 | fs->saw_z = 1; |
277 | ++aug; |
278 | } |
279 | |
280 | /* Iterate over recognized augmentation subsequences. */ |
281 | while (*aug != '\0') |
282 | { |
283 | /* "L" indicates a byte showing how the LSDA pointer is encoded. */ |
284 | if (aug[0] == 'L') |
285 | { |
286 | fs->lsda_encoding = *p++; |
287 | aug += 1; |
288 | } |
289 | |
290 | /* "R" indicates a byte indicating how FDE addresses are encoded. */ |
291 | else if (aug[0] == 'R') |
292 | { |
293 | fs->fde_encoding = *p++; |
294 | aug += 1; |
295 | } |
296 | |
297 | /* "P" indicates a personality routine in the CIE augmentation. */ |
298 | else if (aug[0] == 'P') |
299 | { |
300 | _Unwind_Ptr personality; |
301 | p = read_encoded_value (context, encoding: *p, p: p + 1, val: &personality); |
302 | fs->personality = (_Unwind_Personality_Fn) personality; |
303 | aug += 1; |
304 | } |
305 | |
306 | /* Otherwise we have an unknown augmentation string. |
307 | Bail unless we saw a 'z' prefix. */ |
308 | else |
309 | return ret; |
310 | } |
311 | |
312 | return ret ? ret : p; |
313 | } |
314 | |
315 | #ifndef _LIBC |
316 | /* Decode a DW_OP stack program. Return the top of stack. Push INITIAL |
317 | onto the stack to start. */ |
318 | |
319 | static _Unwind_Word |
320 | execute_stack_op (const unsigned char *op_ptr, const unsigned char *op_end, |
321 | struct _Unwind_Context *context, _Unwind_Word initial) |
322 | { |
323 | _Unwind_Word stack[64]; /* ??? Assume this is enough. */ |
324 | int stack_elt; |
325 | |
326 | stack[0] = initial; |
327 | stack_elt = 1; |
328 | |
329 | while (op_ptr < op_end) |
330 | { |
331 | enum dwarf_location_atom op = *op_ptr++; |
332 | _Unwind_Word result, reg, utmp; |
333 | _Unwind_Sword offset, stmp; |
334 | |
335 | switch (op) |
336 | { |
337 | case DW_OP_lit0: |
338 | case DW_OP_lit1: |
339 | case DW_OP_lit2: |
340 | case DW_OP_lit3: |
341 | case DW_OP_lit4: |
342 | case DW_OP_lit5: |
343 | case DW_OP_lit6: |
344 | case DW_OP_lit7: |
345 | case DW_OP_lit8: |
346 | case DW_OP_lit9: |
347 | case DW_OP_lit10: |
348 | case DW_OP_lit11: |
349 | case DW_OP_lit12: |
350 | case DW_OP_lit13: |
351 | case DW_OP_lit14: |
352 | case DW_OP_lit15: |
353 | case DW_OP_lit16: |
354 | case DW_OP_lit17: |
355 | case DW_OP_lit18: |
356 | case DW_OP_lit19: |
357 | case DW_OP_lit20: |
358 | case DW_OP_lit21: |
359 | case DW_OP_lit22: |
360 | case DW_OP_lit23: |
361 | case DW_OP_lit24: |
362 | case DW_OP_lit25: |
363 | case DW_OP_lit26: |
364 | case DW_OP_lit27: |
365 | case DW_OP_lit28: |
366 | case DW_OP_lit29: |
367 | case DW_OP_lit30: |
368 | case DW_OP_lit31: |
369 | result = op - DW_OP_lit0; |
370 | break; |
371 | |
372 | case DW_OP_addr: |
373 | result = (_Unwind_Word) (_Unwind_Ptr) read_pointer (op_ptr); |
374 | op_ptr += sizeof (void *); |
375 | break; |
376 | |
377 | case DW_OP_const1u: |
378 | result = read_1u (op_ptr); |
379 | op_ptr += 1; |
380 | break; |
381 | case DW_OP_const1s: |
382 | result = read_1s (op_ptr); |
383 | op_ptr += 1; |
384 | break; |
385 | case DW_OP_const2u: |
386 | result = read_2u (op_ptr); |
387 | op_ptr += 2; |
388 | break; |
389 | case DW_OP_const2s: |
390 | result = read_2s (op_ptr); |
391 | op_ptr += 2; |
392 | break; |
393 | case DW_OP_const4u: |
394 | result = read_4u (op_ptr); |
395 | op_ptr += 4; |
396 | break; |
397 | case DW_OP_const4s: |
398 | result = read_4s (op_ptr); |
399 | op_ptr += 4; |
400 | break; |
401 | case DW_OP_const8u: |
402 | result = read_8u (op_ptr); |
403 | op_ptr += 8; |
404 | break; |
405 | case DW_OP_const8s: |
406 | result = read_8s (op_ptr); |
407 | op_ptr += 8; |
408 | break; |
409 | case DW_OP_constu: |
410 | op_ptr = read_uleb128 (op_ptr, &result); |
411 | break; |
412 | case DW_OP_consts: |
413 | op_ptr = read_sleb128 (op_ptr, &stmp); |
414 | result = stmp; |
415 | break; |
416 | |
417 | case DW_OP_reg0: |
418 | case DW_OP_reg1: |
419 | case DW_OP_reg2: |
420 | case DW_OP_reg3: |
421 | case DW_OP_reg4: |
422 | case DW_OP_reg5: |
423 | case DW_OP_reg6: |
424 | case DW_OP_reg7: |
425 | case DW_OP_reg8: |
426 | case DW_OP_reg9: |
427 | case DW_OP_reg10: |
428 | case DW_OP_reg11: |
429 | case DW_OP_reg12: |
430 | case DW_OP_reg13: |
431 | case DW_OP_reg14: |
432 | case DW_OP_reg15: |
433 | case DW_OP_reg16: |
434 | case DW_OP_reg17: |
435 | case DW_OP_reg18: |
436 | case DW_OP_reg19: |
437 | case DW_OP_reg20: |
438 | case DW_OP_reg21: |
439 | case DW_OP_reg22: |
440 | case DW_OP_reg23: |
441 | case DW_OP_reg24: |
442 | case DW_OP_reg25: |
443 | case DW_OP_reg26: |
444 | case DW_OP_reg27: |
445 | case DW_OP_reg28: |
446 | case DW_OP_reg29: |
447 | case DW_OP_reg30: |
448 | case DW_OP_reg31: |
449 | result = _Unwind_GetGR (context, op - DW_OP_reg0); |
450 | break; |
451 | case DW_OP_regx: |
452 | op_ptr = read_uleb128 (op_ptr, ®); |
453 | result = _Unwind_GetGR (context, reg); |
454 | break; |
455 | |
456 | case DW_OP_breg0: |
457 | case DW_OP_breg1: |
458 | case DW_OP_breg2: |
459 | case DW_OP_breg3: |
460 | case DW_OP_breg4: |
461 | case DW_OP_breg5: |
462 | case DW_OP_breg6: |
463 | case DW_OP_breg7: |
464 | case DW_OP_breg8: |
465 | case DW_OP_breg9: |
466 | case DW_OP_breg10: |
467 | case DW_OP_breg11: |
468 | case DW_OP_breg12: |
469 | case DW_OP_breg13: |
470 | case DW_OP_breg14: |
471 | case DW_OP_breg15: |
472 | case DW_OP_breg16: |
473 | case DW_OP_breg17: |
474 | case DW_OP_breg18: |
475 | case DW_OP_breg19: |
476 | case DW_OP_breg20: |
477 | case DW_OP_breg21: |
478 | case DW_OP_breg22: |
479 | case DW_OP_breg23: |
480 | case DW_OP_breg24: |
481 | case DW_OP_breg25: |
482 | case DW_OP_breg26: |
483 | case DW_OP_breg27: |
484 | case DW_OP_breg28: |
485 | case DW_OP_breg29: |
486 | case DW_OP_breg30: |
487 | case DW_OP_breg31: |
488 | op_ptr = read_sleb128 (op_ptr, &offset); |
489 | result = _Unwind_GetGR (context, op - DW_OP_breg0) + offset; |
490 | break; |
491 | case DW_OP_bregx: |
492 | op_ptr = read_uleb128 (op_ptr, ®); |
493 | op_ptr = read_sleb128 (op_ptr, &offset); |
494 | result = _Unwind_GetGR (context, reg) + offset; |
495 | break; |
496 | |
497 | case DW_OP_dup: |
498 | if (stack_elt < 1) |
499 | abort (); |
500 | result = stack[stack_elt - 1]; |
501 | break; |
502 | |
503 | case DW_OP_drop: |
504 | if (--stack_elt < 0) |
505 | abort (); |
506 | goto no_push; |
507 | |
508 | case DW_OP_pick: |
509 | offset = *op_ptr++; |
510 | if (offset >= stack_elt - 1) |
511 | abort (); |
512 | result = stack[stack_elt - 1 - offset]; |
513 | break; |
514 | |
515 | case DW_OP_over: |
516 | if (stack_elt < 2) |
517 | abort (); |
518 | result = stack[stack_elt - 2]; |
519 | break; |
520 | |
521 | case DW_OP_rot: |
522 | { |
523 | _Unwind_Word t1, t2, t3; |
524 | |
525 | if (stack_elt < 3) |
526 | abort (); |
527 | t1 = stack[stack_elt - 1]; |
528 | t2 = stack[stack_elt - 2]; |
529 | t3 = stack[stack_elt - 3]; |
530 | stack[stack_elt - 1] = t2; |
531 | stack[stack_elt - 2] = t3; |
532 | stack[stack_elt - 3] = t1; |
533 | goto no_push; |
534 | } |
535 | |
536 | case DW_OP_deref: |
537 | case DW_OP_deref_size: |
538 | case DW_OP_abs: |
539 | case DW_OP_neg: |
540 | case DW_OP_not: |
541 | case DW_OP_plus_uconst: |
542 | /* Unary operations. */ |
543 | if (--stack_elt < 0) |
544 | abort (); |
545 | result = stack[stack_elt]; |
546 | |
547 | switch (op) |
548 | { |
549 | case DW_OP_deref: |
550 | { |
551 | void *ptr = (void *) (_Unwind_Ptr) result; |
552 | result = (_Unwind_Ptr) read_pointer (ptr); |
553 | } |
554 | break; |
555 | |
556 | case DW_OP_deref_size: |
557 | { |
558 | void *ptr = (void *) (_Unwind_Ptr) result; |
559 | switch (*op_ptr++) |
560 | { |
561 | case 1: |
562 | result = read_1u (ptr); |
563 | break; |
564 | case 2: |
565 | result = read_2u (ptr); |
566 | break; |
567 | case 4: |
568 | result = read_4u (ptr); |
569 | break; |
570 | case 8: |
571 | result = read_8u (ptr); |
572 | break; |
573 | default: |
574 | abort (); |
575 | } |
576 | } |
577 | break; |
578 | |
579 | case DW_OP_abs: |
580 | if ((_Unwind_Sword) result < 0) |
581 | result = -result; |
582 | break; |
583 | case DW_OP_neg: |
584 | result = -result; |
585 | break; |
586 | case DW_OP_not: |
587 | result = ~result; |
588 | break; |
589 | case DW_OP_plus_uconst: |
590 | op_ptr = read_uleb128 (op_ptr, &utmp); |
591 | result += utmp; |
592 | break; |
593 | |
594 | default: |
595 | abort (); |
596 | } |
597 | break; |
598 | |
599 | case DW_OP_and: |
600 | case DW_OP_div: |
601 | case DW_OP_minus: |
602 | case DW_OP_mod: |
603 | case DW_OP_mul: |
604 | case DW_OP_or: |
605 | case DW_OP_plus: |
606 | case DW_OP_le: |
607 | case DW_OP_ge: |
608 | case DW_OP_eq: |
609 | case DW_OP_lt: |
610 | case DW_OP_gt: |
611 | case DW_OP_ne: |
612 | { |
613 | /* Binary operations. */ |
614 | _Unwind_Word first, second; |
615 | if ((stack_elt -= 2) < 0) |
616 | abort (); |
617 | second = stack[stack_elt]; |
618 | first = stack[stack_elt + 1]; |
619 | |
620 | switch (op) |
621 | { |
622 | case DW_OP_and: |
623 | result = second & first; |
624 | break; |
625 | case DW_OP_div: |
626 | result = (_Unwind_Sword) second / (_Unwind_Sword) first; |
627 | break; |
628 | case DW_OP_minus: |
629 | result = second - first; |
630 | break; |
631 | case DW_OP_mod: |
632 | result = (_Unwind_Sword) second % (_Unwind_Sword) first; |
633 | break; |
634 | case DW_OP_mul: |
635 | result = second * first; |
636 | break; |
637 | case DW_OP_or: |
638 | result = second | first; |
639 | break; |
640 | case DW_OP_plus: |
641 | result = second + first; |
642 | break; |
643 | case DW_OP_shl: |
644 | result = second << first; |
645 | break; |
646 | case DW_OP_shr: |
647 | result = second >> first; |
648 | break; |
649 | case DW_OP_shra: |
650 | result = (_Unwind_Sword) second >> first; |
651 | break; |
652 | case DW_OP_xor: |
653 | result = second ^ first; |
654 | break; |
655 | case DW_OP_le: |
656 | result = (_Unwind_Sword) first <= (_Unwind_Sword) second; |
657 | break; |
658 | case DW_OP_ge: |
659 | result = (_Unwind_Sword) first >= (_Unwind_Sword) second; |
660 | break; |
661 | case DW_OP_eq: |
662 | result = (_Unwind_Sword) first == (_Unwind_Sword) second; |
663 | break; |
664 | case DW_OP_lt: |
665 | result = (_Unwind_Sword) first < (_Unwind_Sword) second; |
666 | break; |
667 | case DW_OP_gt: |
668 | result = (_Unwind_Sword) first > (_Unwind_Sword) second; |
669 | break; |
670 | case DW_OP_ne: |
671 | result = (_Unwind_Sword) first != (_Unwind_Sword) second; |
672 | break; |
673 | |
674 | default: |
675 | abort (); |
676 | } |
677 | } |
678 | break; |
679 | |
680 | case DW_OP_skip: |
681 | offset = read_2s (op_ptr); |
682 | op_ptr += 2; |
683 | op_ptr += offset; |
684 | goto no_push; |
685 | |
686 | case DW_OP_bra: |
687 | if (--stack_elt < 0) |
688 | abort (); |
689 | offset = read_2s (op_ptr); |
690 | op_ptr += 2; |
691 | if (stack[stack_elt] != 0) |
692 | op_ptr += offset; |
693 | goto no_push; |
694 | |
695 | case DW_OP_nop: |
696 | goto no_push; |
697 | |
698 | default: |
699 | abort (); |
700 | } |
701 | |
702 | /* Most things push a result value. */ |
703 | if ((size_t) stack_elt >= sizeof (stack) / sizeof (*stack)) |
704 | abort (); |
705 | stack[stack_elt++] = result; |
706 | no_push:; |
707 | } |
708 | |
709 | /* We were executing this program to get a value. It should be |
710 | at top of stack. */ |
711 | if (--stack_elt < 0) |
712 | abort (); |
713 | return stack[stack_elt]; |
714 | } |
715 | #endif |
716 | |
717 | /* Decode DWARF 2 call frame information. Takes pointers the |
718 | instruction sequence to decode, current register information and |
719 | CIE info, and the PC range to evaluate. */ |
720 | |
721 | static void |
722 | execute_cfa_program (const unsigned char *insn_ptr, |
723 | const unsigned char *insn_end, |
724 | struct _Unwind_Context *context, |
725 | _Unwind_FrameState *fs) |
726 | { |
727 | struct frame_state_reg_info *unused_rs = NULL; |
728 | |
729 | /* Don't allow remember/restore between CIE and FDE programs. */ |
730 | fs->regs.prev = NULL; |
731 | |
732 | /* The comparison with the return address uses < rather than <= because |
733 | we are only interested in the effects of code before the call; for a |
734 | noreturn function, the return address may point to unrelated code with |
735 | a different stack configuration that we are not interested in. We |
736 | assume that the call itself is unwind info-neutral; if not, or if |
737 | there are delay instructions that adjust the stack, these must be |
738 | reflected at the point immediately before the call insn. */ |
739 | while (insn_ptr < insn_end && fs->pc < context->ra) |
740 | { |
741 | unsigned char insn = *insn_ptr++; |
742 | _Unwind_Word reg, utmp; |
743 | _Unwind_Sword offset, stmp; |
744 | |
745 | if ((insn & 0xc0) == DW_CFA_advance_loc) |
746 | fs->pc += (insn & 0x3f) * fs->code_align; |
747 | else if ((insn & 0xc0) == DW_CFA_offset) |
748 | { |
749 | reg = insn & 0x3f; |
750 | insn_ptr = read_uleb128 (p: insn_ptr, val: &utmp); |
751 | offset = (_Unwind_Sword) utmp * fs->data_align; |
752 | fs->regs.reg[reg].how = REG_SAVED_OFFSET; |
753 | fs->regs.reg[reg].loc.offset = offset; |
754 | } |
755 | else if ((insn & 0xc0) == DW_CFA_restore) |
756 | { |
757 | reg = insn & 0x3f; |
758 | fs->regs.reg[reg].how = REG_UNSAVED; |
759 | } |
760 | else switch (insn) |
761 | { |
762 | case DW_CFA_set_loc: |
763 | { |
764 | _Unwind_Ptr pc; |
765 | insn_ptr = read_encoded_value (context, encoding: fs->fde_encoding, |
766 | p: insn_ptr, val: &pc); |
767 | fs->pc = (void *) pc; |
768 | } |
769 | break; |
770 | |
771 | case DW_CFA_advance_loc1: |
772 | fs->pc += read_1u (p: insn_ptr) * fs->code_align; |
773 | insn_ptr += 1; |
774 | break; |
775 | case DW_CFA_advance_loc2: |
776 | fs->pc += read_2u (p: insn_ptr) * fs->code_align; |
777 | insn_ptr += 2; |
778 | break; |
779 | case DW_CFA_advance_loc4: |
780 | fs->pc += read_4u (p: insn_ptr) * fs->code_align; |
781 | insn_ptr += 4; |
782 | break; |
783 | |
784 | case DW_CFA_offset_extended: |
785 | insn_ptr = read_uleb128 (p: insn_ptr, val: ®); |
786 | insn_ptr = read_uleb128 (p: insn_ptr, val: &utmp); |
787 | offset = (_Unwind_Sword) utmp * fs->data_align; |
788 | fs->regs.reg[reg].how = REG_SAVED_OFFSET; |
789 | fs->regs.reg[reg].loc.offset = offset; |
790 | break; |
791 | |
792 | case DW_CFA_restore_extended: |
793 | insn_ptr = read_uleb128 (p: insn_ptr, val: ®); |
794 | fs->regs.reg[reg].how = REG_UNSAVED; |
795 | break; |
796 | |
797 | case DW_CFA_undefined: |
798 | case DW_CFA_same_value: |
799 | insn_ptr = read_uleb128 (p: insn_ptr, val: ®); |
800 | break; |
801 | |
802 | case DW_CFA_nop: |
803 | break; |
804 | |
805 | case DW_CFA_register: |
806 | { |
807 | _Unwind_Word reg2; |
808 | insn_ptr = read_uleb128 (p: insn_ptr, val: ®); |
809 | insn_ptr = read_uleb128 (p: insn_ptr, val: ®2); |
810 | fs->regs.reg[reg].how = REG_SAVED_REG; |
811 | fs->regs.reg[reg].loc.reg = reg2; |
812 | } |
813 | break; |
814 | |
815 | case DW_CFA_remember_state: |
816 | { |
817 | struct frame_state_reg_info *new_rs; |
818 | if (unused_rs) |
819 | { |
820 | new_rs = unused_rs; |
821 | unused_rs = unused_rs->prev; |
822 | } |
823 | else |
824 | new_rs = __builtin_alloca (sizeof (struct frame_state_reg_info)); |
825 | |
826 | *new_rs = fs->regs; |
827 | fs->regs.prev = new_rs; |
828 | } |
829 | break; |
830 | |
831 | case DW_CFA_restore_state: |
832 | { |
833 | struct frame_state_reg_info *old_rs = fs->regs.prev; |
834 | #ifdef _LIBC |
835 | if (old_rs == NULL) |
836 | __libc_fatal ("Invalid DWARF unwind data.\n" ); |
837 | else |
838 | #endif |
839 | { |
840 | fs->regs = *old_rs; |
841 | old_rs->prev = unused_rs; |
842 | unused_rs = old_rs; |
843 | } |
844 | } |
845 | break; |
846 | |
847 | case DW_CFA_def_cfa: |
848 | insn_ptr = read_uleb128 (p: insn_ptr, val: &fs->cfa_reg); |
849 | insn_ptr = read_uleb128 (p: insn_ptr, val: &utmp); |
850 | fs->cfa_offset = utmp; |
851 | fs->cfa_how = CFA_REG_OFFSET; |
852 | break; |
853 | |
854 | case DW_CFA_def_cfa_register: |
855 | insn_ptr = read_uleb128 (p: insn_ptr, val: &fs->cfa_reg); |
856 | fs->cfa_how = CFA_REG_OFFSET; |
857 | break; |
858 | |
859 | case DW_CFA_def_cfa_offset: |
860 | insn_ptr = read_uleb128 (p: insn_ptr, val: &utmp); |
861 | fs->cfa_offset = utmp; |
862 | /* cfa_how deliberately not set. */ |
863 | break; |
864 | |
865 | case DW_CFA_def_cfa_expression: |
866 | fs->cfa_exp = insn_ptr; |
867 | fs->cfa_how = CFA_EXP; |
868 | insn_ptr = read_uleb128 (p: insn_ptr, val: &utmp); |
869 | insn_ptr += utmp; |
870 | break; |
871 | |
872 | case DW_CFA_expression: |
873 | insn_ptr = read_uleb128 (p: insn_ptr, val: ®); |
874 | fs->regs.reg[reg].how = REG_SAVED_EXP; |
875 | fs->regs.reg[reg].loc.exp = insn_ptr; |
876 | insn_ptr = read_uleb128 (p: insn_ptr, val: &utmp); |
877 | insn_ptr += utmp; |
878 | break; |
879 | |
880 | /* From the 2.1 draft. */ |
881 | case DW_CFA_offset_extended_sf: |
882 | insn_ptr = read_uleb128 (p: insn_ptr, val: ®); |
883 | insn_ptr = read_sleb128 (p: insn_ptr, val: &stmp); |
884 | offset = stmp * fs->data_align; |
885 | fs->regs.reg[reg].how = REG_SAVED_OFFSET; |
886 | fs->regs.reg[reg].loc.offset = offset; |
887 | break; |
888 | |
889 | case DW_CFA_def_cfa_sf: |
890 | insn_ptr = read_uleb128 (p: insn_ptr, val: &fs->cfa_reg); |
891 | insn_ptr = read_sleb128 (p: insn_ptr, val: &fs->cfa_offset); |
892 | fs->cfa_how = CFA_REG_OFFSET; |
893 | break; |
894 | |
895 | case DW_CFA_def_cfa_offset_sf: |
896 | insn_ptr = read_sleb128 (p: insn_ptr, val: &fs->cfa_offset); |
897 | /* cfa_how deliberately not set. */ |
898 | break; |
899 | |
900 | case DW_CFA_GNU_window_save: |
901 | /* ??? Hardcoded for SPARC register window configuration. |
902 | At least do not do anything for archs which explicitly |
903 | define a lower register number. */ |
904 | #if DWARF_FRAME_REGISTERS >= 32 |
905 | for (reg = 16; reg < 32; ++reg) |
906 | { |
907 | fs->regs.reg[reg].how = REG_SAVED_OFFSET; |
908 | fs->regs.reg[reg].loc.offset = (reg - 16) * sizeof (void *); |
909 | } |
910 | #endif |
911 | break; |
912 | |
913 | case DW_CFA_GNU_args_size: |
914 | insn_ptr = read_uleb128 (p: insn_ptr, val: &context->args_size); |
915 | break; |
916 | |
917 | case DW_CFA_GNU_negative_offset_extended: |
918 | /* Obsoleted by DW_CFA_offset_extended_sf, but used by |
919 | older PowerPC code. */ |
920 | insn_ptr = read_uleb128 (p: insn_ptr, val: ®); |
921 | insn_ptr = read_uleb128 (p: insn_ptr, val: &utmp); |
922 | offset = (_Unwind_Word) utmp * fs->data_align; |
923 | fs->regs.reg[reg].how = REG_SAVED_OFFSET; |
924 | fs->regs.reg[reg].loc.offset = -offset; |
925 | break; |
926 | |
927 | default: |
928 | abort (); |
929 | } |
930 | } |
931 | } |
932 | |
933 | /* Given the _Unwind_Context CONTEXT for a stack frame, look up the FDE for |
934 | its caller and decode it into FS. This function also sets the |
935 | args_size and lsda members of CONTEXT, as they are really information |
936 | about the caller's frame. */ |
937 | |
938 | static _Unwind_Reason_Code |
939 | uw_frame_state_for (struct _Unwind_Context *context, _Unwind_FrameState *fs) |
940 | { |
941 | struct dwarf_fde *fde; |
942 | struct dwarf_cie *cie; |
943 | const unsigned char *aug, *insn, *end; |
944 | |
945 | memset (fs, 0, sizeof (*fs)); |
946 | context->args_size = 0; |
947 | context->lsda = 0; |
948 | |
949 | fde = _Unwind_Find_FDE (context->ra - 1, &context->bases); |
950 | if (fde == NULL) |
951 | { |
952 | /* Couldn't find frame unwind info for this function. Try a |
953 | target-specific fallback mechanism. This will necessarily |
954 | not provide a personality routine or LSDA. */ |
955 | #ifdef MD_FALLBACK_FRAME_STATE_FOR |
956 | MD_FALLBACK_FRAME_STATE_FOR (context, fs, success); |
957 | return _URC_END_OF_STACK; |
958 | success: |
959 | return _URC_NO_REASON; |
960 | #else |
961 | return _URC_END_OF_STACK; |
962 | #endif |
963 | } |
964 | |
965 | fs->pc = context->bases.func; |
966 | |
967 | cie = get_cie (f: fde); |
968 | insn = extract_cie_info (cie, context, fs); |
969 | if (insn == NULL) |
970 | /* CIE contained unknown augmentation. */ |
971 | return _URC_FATAL_PHASE1_ERROR; |
972 | |
973 | /* First decode all the insns in the CIE. */ |
974 | end = (unsigned char *) next_fde (f: (struct dwarf_fde *) cie); |
975 | execute_cfa_program (insn_ptr: insn, insn_end: end, context, fs); |
976 | |
977 | /* Locate augmentation for the fde. */ |
978 | aug = (unsigned char *) fde + sizeof (*fde); |
979 | aug += 2 * size_of_encoded_value (encoding: fs->fde_encoding); |
980 | insn = NULL; |
981 | if (fs->saw_z) |
982 | { |
983 | _Unwind_Word i; |
984 | aug = read_uleb128 (p: aug, val: &i); |
985 | insn = aug + i; |
986 | } |
987 | if (fs->lsda_encoding != DW_EH_PE_omit) |
988 | { |
989 | _Unwind_Ptr lsda; |
990 | aug = read_encoded_value (context, encoding: fs->lsda_encoding, p: aug, val: &lsda); |
991 | context->lsda = (void *) lsda; |
992 | } |
993 | |
994 | /* Then the insns in the FDE up to our target PC. */ |
995 | if (insn == NULL) |
996 | insn = aug; |
997 | end = (unsigned char *) next_fde (f: fde); |
998 | execute_cfa_program (insn_ptr: insn, insn_end: end, context, fs); |
999 | |
1000 | return _URC_NO_REASON; |
1001 | } |
1002 | |
1003 | typedef struct frame_state |
1004 | { |
1005 | void *cfa; |
1006 | void *eh_ptr; |
1007 | long cfa_offset; |
1008 | long args_size; |
1009 | long reg_or_offset[PRE_GCC3_DWARF_FRAME_REGISTERS+1]; |
1010 | unsigned short cfa_reg; |
1011 | unsigned short retaddr_column; |
1012 | char saved[PRE_GCC3_DWARF_FRAME_REGISTERS+1]; |
1013 | } frame_state; |
1014 | |
1015 | #ifndef STATIC |
1016 | # define STATIC |
1017 | #endif |
1018 | |
1019 | STATIC |
1020 | struct frame_state * __frame_state_for (void *, struct frame_state *); |
1021 | |
1022 | /* Called from pre-G++ 3.0 __throw to find the registers to restore for |
1023 | a given PC_TARGET. The caller should allocate a local variable of |
1024 | `struct frame_state' and pass its address to STATE_IN. */ |
1025 | |
1026 | STATIC |
1027 | struct frame_state * |
1028 | __frame_state_for (void *pc_target, struct frame_state *state_in) |
1029 | { |
1030 | struct _Unwind_Context context; |
1031 | _Unwind_FrameState fs; |
1032 | int reg; |
1033 | |
1034 | memset (&context, 0, sizeof (struct _Unwind_Context)); |
1035 | context.ra = pc_target + 1; |
1036 | |
1037 | if (uw_frame_state_for (context: &context, fs: &fs) != _URC_NO_REASON) |
1038 | return 0; |
1039 | |
1040 | /* We have no way to pass a location expression for the CFA to our |
1041 | caller. It wouldn't understand it anyway. */ |
1042 | if (fs.cfa_how == CFA_EXP) |
1043 | return 0; |
1044 | |
1045 | for (reg = 0; reg < PRE_GCC3_DWARF_FRAME_REGISTERS + 1; reg++) |
1046 | { |
1047 | state_in->saved[reg] = fs.regs.reg[reg].how; |
1048 | switch (state_in->saved[reg]) |
1049 | { |
1050 | case REG_SAVED_REG: |
1051 | state_in->reg_or_offset[reg] = fs.regs.reg[reg].loc.reg; |
1052 | break; |
1053 | case REG_SAVED_OFFSET: |
1054 | state_in->reg_or_offset[reg] = fs.regs.reg[reg].loc.offset; |
1055 | break; |
1056 | default: |
1057 | state_in->reg_or_offset[reg] = 0; |
1058 | break; |
1059 | } |
1060 | } |
1061 | |
1062 | state_in->cfa_offset = fs.cfa_offset; |
1063 | state_in->cfa_reg = fs.cfa_reg; |
1064 | state_in->retaddr_column = fs.retaddr_column; |
1065 | state_in->args_size = context.args_size; |
1066 | state_in->eh_ptr = fs.eh_ptr; |
1067 | |
1068 | return state_in; |
1069 | } |
1070 | |
1071 | #ifndef _LIBC |
1072 | |
1073 | static void |
1074 | uw_update_context_1 (struct _Unwind_Context *context, _Unwind_FrameState *fs) |
1075 | { |
1076 | struct _Unwind_Context orig_context = *context; |
1077 | void *cfa; |
1078 | long i; |
1079 | |
1080 | #ifdef EH_RETURN_STACKADJ_RTX |
1081 | /* Special handling here: Many machines do not use a frame pointer, |
1082 | and track the CFA only through offsets from the stack pointer from |
1083 | one frame to the next. In this case, the stack pointer is never |
1084 | stored, so it has no saved address in the context. What we do |
1085 | have is the CFA from the previous stack frame. |
1086 | |
1087 | In very special situations (such as unwind info for signal return), |
1088 | there may be location expressions that use the stack pointer as well. |
1089 | |
1090 | Do this conditionally for one frame. This allows the unwind info |
1091 | for one frame to save a copy of the stack pointer from the previous |
1092 | frame, and be able to use much easier CFA mechanisms to do it. |
1093 | Always zap the saved stack pointer value for the next frame; carrying |
1094 | the value over from one frame to another doesn't make sense. */ |
1095 | |
1096 | _Unwind_Word tmp_sp; |
1097 | |
1098 | if (!orig_context.reg[__builtin_dwarf_sp_column ()]) |
1099 | { |
1100 | tmp_sp = (_Unwind_Ptr) context->cfa; |
1101 | orig_context.reg[__builtin_dwarf_sp_column ()] = &tmp_sp; |
1102 | } |
1103 | context->reg[__builtin_dwarf_sp_column ()] = NULL; |
1104 | #endif |
1105 | |
1106 | /* Compute this frame's CFA. */ |
1107 | switch (fs->cfa_how) |
1108 | { |
1109 | case CFA_REG_OFFSET: |
1110 | cfa = (void *) (_Unwind_Ptr) _Unwind_GetGR (&orig_context, fs->cfa_reg); |
1111 | cfa += fs->cfa_offset; |
1112 | break; |
1113 | |
1114 | case CFA_EXP: |
1115 | { |
1116 | const unsigned char *exp = fs->cfa_exp; |
1117 | _Unwind_Word len; |
1118 | |
1119 | exp = read_uleb128 (exp, &len); |
1120 | cfa = (void *) (_Unwind_Ptr) |
1121 | execute_stack_op (exp, exp + len, &orig_context, 0); |
1122 | break; |
1123 | } |
1124 | |
1125 | default: |
1126 | abort (); |
1127 | } |
1128 | context->cfa = cfa; |
1129 | |
1130 | /* Compute the addresses of all registers saved in this frame. */ |
1131 | for (i = 0; i < DWARF_FRAME_REGISTERS + 1; ++i) |
1132 | switch (fs->regs.reg[i].how) |
1133 | { |
1134 | case REG_UNSAVED: |
1135 | break; |
1136 | |
1137 | case REG_SAVED_OFFSET: |
1138 | context->reg[i] = cfa + fs->regs.reg[i].loc.offset; |
1139 | break; |
1140 | |
1141 | case REG_SAVED_REG: |
1142 | context->reg[i] = orig_context.reg[fs->regs.reg[i].loc.reg]; |
1143 | break; |
1144 | |
1145 | case REG_SAVED_EXP: |
1146 | { |
1147 | const unsigned char *exp = fs->regs.reg[i].loc.exp; |
1148 | _Unwind_Word len; |
1149 | _Unwind_Ptr val; |
1150 | |
1151 | exp = read_uleb128 (exp, &len); |
1152 | val = execute_stack_op (exp, exp + len, &orig_context, |
1153 | (_Unwind_Ptr) cfa); |
1154 | context->reg[i] = (void *) val; |
1155 | } |
1156 | break; |
1157 | } |
1158 | } |
1159 | |
1160 | /* CONTEXT describes the unwind state for a frame, and FS describes the FDE |
1161 | of its caller. Update CONTEXT to refer to the caller as well. Note |
1162 | that the args_size and lsda members are not updated here, but later in |
1163 | uw_frame_state_for. */ |
1164 | |
1165 | static void |
1166 | uw_update_context (struct _Unwind_Context *context, _Unwind_FrameState *fs) |
1167 | { |
1168 | uw_update_context_1 (context, fs); |
1169 | |
1170 | /* Compute the return address now, since the return address column |
1171 | can change from frame to frame. */ |
1172 | context->ra = __builtin_extract_return_addr |
1173 | ((void *) (_Unwind_Ptr) _Unwind_GetGR (context, fs->retaddr_column)); |
1174 | } |
1175 | |
1176 | /* Fill in CONTEXT for top-of-stack. The only valid registers at this |
1177 | level will be the return address and the CFA. */ |
1178 | |
1179 | #define uw_init_context(CONTEXT) \ |
1180 | do \ |
1181 | { \ |
1182 | /* Do any necessary initialization to access arbitrary stack frames. \ |
1183 | On the SPARC, this means flushing the register windows. */ \ |
1184 | __builtin_unwind_init (); \ |
1185 | uw_init_context_1 (CONTEXT, __builtin_dwarf_cfa (), \ |
1186 | __builtin_return_address (0)); \ |
1187 | } \ |
1188 | while (0) |
1189 | |
1190 | static void |
1191 | uw_init_context_1 (struct _Unwind_Context *context, |
1192 | void *outer_cfa, void *outer_ra) |
1193 | { |
1194 | void *ra = __builtin_extract_return_addr (__builtin_return_address (0)); |
1195 | _Unwind_FrameState fs; |
1196 | _Unwind_Word sp_slot; |
1197 | |
1198 | memset (context, 0, sizeof (struct _Unwind_Context)); |
1199 | context->ra = ra; |
1200 | |
1201 | if (uw_frame_state_for (context, &fs) != _URC_NO_REASON) |
1202 | abort (); |
1203 | |
1204 | /* Force the frame state to use the known cfa value. */ |
1205 | sp_slot = (_Unwind_Ptr) outer_cfa; |
1206 | context->reg[__builtin_dwarf_sp_column ()] = &sp_slot; |
1207 | fs.cfa_how = CFA_REG_OFFSET; |
1208 | fs.cfa_reg = __builtin_dwarf_sp_column (); |
1209 | fs.cfa_offset = 0; |
1210 | |
1211 | uw_update_context_1 (context, &fs); |
1212 | |
1213 | /* If the return address column was saved in a register in the |
1214 | initialization context, then we can't see it in the given |
1215 | call frame data. So have the initialization context tell us. */ |
1216 | context->ra = __builtin_extract_return_addr (outer_ra); |
1217 | } |
1218 | |
1219 | |
1220 | /* Install TARGET into CURRENT so that we can return to it. This is a |
1221 | macro because __builtin_eh_return must be invoked in the context of |
1222 | our caller. */ |
1223 | |
1224 | #define uw_install_context(CURRENT, TARGET) \ |
1225 | do \ |
1226 | { \ |
1227 | long offset = uw_install_context_1 ((CURRENT), (TARGET)); \ |
1228 | void *handler = __builtin_frob_return_addr ((TARGET)->ra); \ |
1229 | __builtin_eh_return (offset, handler); \ |
1230 | } \ |
1231 | while (0) |
1232 | |
1233 | static inline void |
1234 | init_dwarf_reg_size_table (void) |
1235 | { |
1236 | __builtin_init_dwarf_reg_size_table (dwarf_reg_size_table); |
1237 | } |
1238 | |
1239 | static long |
1240 | uw_install_context_1 (struct _Unwind_Context *current, |
1241 | struct _Unwind_Context *target) |
1242 | { |
1243 | long i; |
1244 | |
1245 | #if __GTHREADS |
1246 | { |
1247 | static __gthread_once_t once_regsizes = __GTHREAD_ONCE_INIT; |
1248 | if (__gthread_once (&once_regsizes, init_dwarf_reg_size_table) != 0 |
1249 | || dwarf_reg_size_table[0] == 0) |
1250 | init_dwarf_reg_size_table (); |
1251 | } |
1252 | #else |
1253 | if (dwarf_reg_size_table[0] == 0) |
1254 | init_dwarf_reg_size_table (); |
1255 | #endif |
1256 | |
1257 | for (i = 0; i < DWARF_FRAME_REGISTERS; ++i) |
1258 | { |
1259 | void *c = current->reg[i]; |
1260 | void *t = target->reg[i]; |
1261 | if (t && c && t != c) |
1262 | memcpy (c, t, dwarf_reg_size_table[i]); |
1263 | } |
1264 | |
1265 | #ifdef EH_RETURN_STACKADJ_RTX |
1266 | { |
1267 | void *target_cfa; |
1268 | |
1269 | /* If the last frame records a saved stack pointer, use it. */ |
1270 | if (target->reg[__builtin_dwarf_sp_column ()]) |
1271 | target_cfa = (void *)(_Unwind_Ptr) |
1272 | _Unwind_GetGR (target, __builtin_dwarf_sp_column ()); |
1273 | else |
1274 | target_cfa = target->cfa; |
1275 | |
1276 | /* We adjust SP by the difference between CURRENT and TARGET's CFA. */ |
1277 | if (STACK_GROWS_DOWNWARD) |
1278 | return target_cfa - current->cfa + target->args_size; |
1279 | else |
1280 | return current->cfa - target_cfa - target->args_size; |
1281 | } |
1282 | #else |
1283 | return 0; |
1284 | #endif |
1285 | } |
1286 | |
1287 | static inline _Unwind_Ptr |
1288 | uw_identify_context (struct _Unwind_Context *context) |
1289 | { |
1290 | return _Unwind_GetIP (context); |
1291 | } |
1292 | |
1293 | |
1294 | #include "unwind.inc" |
1295 | |
1296 | #endif /* _LIBC */ |
1297 | |