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1e874273 | 1 | /* Common unwinding code for ARM EABI and C6X. |
85ec4feb | 2 | Copyright (C) 2004-2018 Free Software Foundation, Inc. |
1e874273 PB |
3 | Contributed by Paul Brook |
4 | ||
5 | This file is free software; you can redistribute it and/or modify it | |
6 | under the terms of the GNU General Public License as published by the | |
7 | Free Software Foundation; either version 3, or (at your option) any | |
8 | later version. | |
9 | ||
10 | This file is distributed in the hope that it will be useful, but | |
11 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
13 | General Public License for more details. | |
14 | ||
15 | Under Section 7 of GPL version 3, you are granted additional | |
16 | permissions described in the GCC Runtime Library Exception, version | |
17 | 3.1, as published by the Free Software Foundation. | |
18 | ||
19 | You should have received a copy of the GNU General Public License and | |
20 | a copy of the GCC Runtime Library Exception along with this program; | |
21 | see the files COPYING3 and COPYING.RUNTIME respectively. If not, see | |
22 | <http://www.gnu.org/licenses/>. */ | |
23 | ||
69048898 SDJ |
24 | #include "tconfig.h" |
25 | #include "tsystem.h" | |
1e874273 PB |
26 | #include "unwind.h" |
27 | ||
69048898 SDJ |
28 | /* Used for SystemTap unwinder probe. */ |
29 | #ifdef HAVE_SYS_SDT_H | |
30 | #include <sys/sdt.h> | |
31 | #endif | |
32 | ||
1e874273 PB |
33 | /* We add a prototype for abort here to avoid creating a dependency on |
34 | target headers. */ | |
35 | extern void abort (void); | |
36 | ||
37 | /* Definitions for C++ runtime support routines. We make these weak | |
38 | declarations to avoid pulling in libsupc++ unnecessarily. */ | |
39 | typedef unsigned char bool; | |
40 | ||
41 | typedef struct _ZSt9type_info type_info; /* This names C++ type_info type */ | |
42 | enum __cxa_type_match_result | |
43 | { | |
44 | ctm_failed = 0, | |
45 | ctm_succeeded = 1, | |
46 | ctm_succeeded_with_ptr_to_base = 2 | |
47 | }; | |
48 | ||
49 | void __attribute__((weak)) __cxa_call_unexpected(_Unwind_Control_Block *ucbp); | |
50 | bool __attribute__((weak)) __cxa_begin_cleanup(_Unwind_Control_Block *ucbp); | |
51 | enum __cxa_type_match_result __attribute__((weak)) __cxa_type_match | |
52 | (_Unwind_Control_Block *ucbp, const type_info *rttip, | |
53 | bool is_reference, void **matched_object); | |
54 | ||
55 | _Unwind_Ptr __attribute__((weak)) | |
56 | __gnu_Unwind_Find_exidx (_Unwind_Ptr, int *); | |
57 | ||
58 | #define EXIDX_CANTUNWIND 1 | |
59 | #define uint32_highbit (((_uw) 1) << 31) | |
60 | ||
61 | #define UCB_FORCED_STOP_FN(ucbp) ((ucbp)->unwinder_cache.reserved1) | |
62 | #define UCB_PR_ADDR(ucbp) ((ucbp)->unwinder_cache.reserved2) | |
63 | #define UCB_SAVED_CALLSITE_ADDR(ucbp) ((ucbp)->unwinder_cache.reserved3) | |
64 | #define UCB_FORCED_STOP_ARG(ucbp) ((ucbp)->unwinder_cache.reserved4) | |
65 | ||
66 | /* Unwind descriptors. */ | |
67 | ||
68 | typedef struct | |
69 | { | |
70 | _uw16 length; | |
71 | _uw16 offset; | |
72 | } EHT16; | |
73 | ||
74 | typedef struct | |
75 | { | |
76 | _uw length; | |
77 | _uw offset; | |
78 | } EHT32; | |
79 | ||
80 | /* An exception index table entry. */ | |
81 | ||
82 | typedef struct __EIT_entry | |
83 | { | |
84 | _uw fnoffset; | |
85 | _uw content; | |
86 | } __EIT_entry; | |
87 | ||
88 | /* Assembly helper functions. */ | |
89 | ||
90 | /* Restore core register state. Never returns. */ | |
91 | void __attribute__((noreturn)) restore_core_regs (struct core_regs *); | |
92 | ||
93 | ||
94 | /* Restore coprocessor state after phase1 unwinding. */ | |
95 | static void restore_non_core_regs (phase1_vrs * vrs); | |
96 | ||
97 | /* A better way to do this would probably be to compare the absolute address | |
98 | with a segment relative relocation of the same symbol. */ | |
99 | ||
100 | extern int __text_start; | |
101 | extern int __data_start; | |
102 | ||
103 | /* The exception index table location. */ | |
104 | extern __EIT_entry __exidx_start; | |
105 | extern __EIT_entry __exidx_end; | |
106 | ||
107 | /* Core unwinding functions. */ | |
108 | ||
109 | /* Calculate the address encoded by a 31-bit self-relative offset at address | |
110 | P. */ | |
111 | static inline _uw selfrel_offset31 (const _uw *p); | |
112 | ||
113 | static _uw __gnu_unwind_get_pr_addr (int idx); | |
114 | ||
69048898 SDJ |
115 | static void _Unwind_DebugHook (void *, void *) |
116 | __attribute__ ((__noinline__, __used__, __noclone__)); | |
117 | ||
118 | /* This function is called during unwinding. It is intended as a hook | |
119 | for a debugger to intercept exceptions. CFA is the CFA of the | |
120 | target frame. HANDLER is the PC to which control will be | |
121 | transferred. */ | |
122 | ||
123 | static void | |
124 | _Unwind_DebugHook (void *cfa __attribute__ ((__unused__)), | |
125 | void *handler __attribute__ ((__unused__))) | |
126 | { | |
127 | /* We only want to use stap probes starting with v3. Earlier | |
128 | versions added too much startup cost. */ | |
129 | #if defined (HAVE_SYS_SDT_H) && defined (STAP_PROBE2) && _SDT_NOTE_TYPE >= 3 | |
130 | STAP_PROBE2 (libgcc, unwind, cfa, handler); | |
131 | #else | |
132 | asm (""); | |
133 | #endif | |
134 | } | |
135 | ||
136 | /* This is a wrapper to be called when we need to restore core registers. | |
137 | It will call `_Unwind_DebugHook' before restoring the registers, thus | |
138 | making it possible to intercept and debug exceptions. | |
139 | ||
140 | When calling `_Unwind_DebugHook', the first argument (the CFA) is zero | |
141 | because we are not interested in it. However, it must be there (even | |
142 | being zero) because GDB expects to find it when using the probe. */ | |
143 | ||
144 | #define uw_restore_core_regs(TARGET, CORE) \ | |
145 | do \ | |
146 | { \ | |
147 | void *handler = __builtin_frob_return_addr ((void *) VRS_PC (TARGET)); \ | |
148 | _Unwind_DebugHook (0, handler); \ | |
149 | restore_core_regs (CORE); \ | |
150 | } \ | |
151 | while (0) | |
152 | ||
1e874273 PB |
153 | /* Perform a binary search for RETURN_ADDRESS in TABLE. The table contains |
154 | NREC entries. */ | |
155 | ||
156 | static const __EIT_entry * | |
157 | search_EIT_table (const __EIT_entry * table, int nrec, _uw return_address) | |
158 | { | |
159 | _uw next_fn; | |
160 | _uw this_fn; | |
161 | int n, left, right; | |
162 | ||
163 | if (nrec == 0) | |
164 | return (__EIT_entry *) 0; | |
165 | ||
166 | left = 0; | |
167 | right = nrec - 1; | |
168 | ||
169 | while (1) | |
170 | { | |
171 | n = (left + right) / 2; | |
172 | this_fn = selfrel_offset31 (&table[n].fnoffset); | |
173 | if (n != nrec - 1) | |
174 | next_fn = selfrel_offset31 (&table[n + 1].fnoffset) - 1; | |
175 | else | |
176 | next_fn = (_uw)0 - 1; | |
177 | ||
178 | if (return_address < this_fn) | |
179 | { | |
180 | if (n == left) | |
181 | return (__EIT_entry *) 0; | |
182 | right = n - 1; | |
183 | } | |
184 | else if (return_address <= next_fn) | |
185 | return &table[n]; | |
186 | else | |
187 | left = n + 1; | |
188 | } | |
189 | } | |
190 | ||
191 | /* Find the exception index table eintry for the given address. | |
192 | Fill in the relevant fields of the UCB. | |
193 | Returns _URC_FAILURE if an error occurred, _URC_OK on success. */ | |
194 | ||
195 | static _Unwind_Reason_Code | |
196 | get_eit_entry (_Unwind_Control_Block *ucbp, _uw return_address) | |
197 | { | |
198 | const __EIT_entry * eitp; | |
199 | int nrec; | |
200 | ||
201 | /* The return address is the address of the instruction following the | |
202 | call instruction (plus one in thumb mode). If this was the last | |
203 | instruction in the function the address will lie in the following | |
204 | function. Subtract 2 from the address so that it points within the call | |
205 | instruction itself. */ | |
206 | return_address -= 2; | |
207 | ||
208 | if (__gnu_Unwind_Find_exidx) | |
209 | { | |
210 | eitp = (const __EIT_entry *) __gnu_Unwind_Find_exidx (return_address, | |
211 | &nrec); | |
212 | if (!eitp) | |
213 | { | |
214 | UCB_PR_ADDR (ucbp) = 0; | |
215 | return _URC_FAILURE; | |
216 | } | |
217 | } | |
218 | else | |
219 | { | |
220 | eitp = &__exidx_start; | |
221 | nrec = &__exidx_end - &__exidx_start; | |
222 | } | |
223 | ||
224 | eitp = search_EIT_table (eitp, nrec, return_address); | |
225 | ||
226 | if (!eitp) | |
227 | { | |
228 | UCB_PR_ADDR (ucbp) = 0; | |
229 | return _URC_FAILURE; | |
230 | } | |
231 | ucbp->pr_cache.fnstart = selfrel_offset31 (&eitp->fnoffset); | |
232 | ||
233 | /* Can this frame be unwound at all? */ | |
234 | if (eitp->content == EXIDX_CANTUNWIND) | |
235 | { | |
236 | UCB_PR_ADDR (ucbp) = 0; | |
237 | return _URC_END_OF_STACK; | |
238 | } | |
239 | ||
240 | /* Obtain the address of the "real" __EHT_Header word. */ | |
241 | ||
242 | if (eitp->content & uint32_highbit) | |
243 | { | |
244 | /* It is immediate data. */ | |
245 | ucbp->pr_cache.ehtp = (_Unwind_EHT_Header *)&eitp->content; | |
246 | ucbp->pr_cache.additional = 1; | |
247 | } | |
248 | else | |
249 | { | |
250 | /* The low 31 bits of the content field are a self-relative | |
251 | offset to an _Unwind_EHT_Entry structure. */ | |
252 | ucbp->pr_cache.ehtp = | |
253 | (_Unwind_EHT_Header *) selfrel_offset31 (&eitp->content); | |
254 | ucbp->pr_cache.additional = 0; | |
255 | } | |
256 | ||
257 | /* Discover the personality routine address. */ | |
258 | if (*ucbp->pr_cache.ehtp & (1u << 31)) | |
259 | { | |
260 | /* One of the predefined standard routines. */ | |
261 | _uw idx = (*(_uw *) ucbp->pr_cache.ehtp >> 24) & 0xf; | |
262 | UCB_PR_ADDR (ucbp) = __gnu_unwind_get_pr_addr (idx); | |
263 | if (UCB_PR_ADDR (ucbp) == 0) | |
264 | { | |
265 | /* Failed */ | |
266 | return _URC_FAILURE; | |
267 | } | |
268 | } | |
269 | else | |
270 | { | |
271 | /* Execute region offset to PR */ | |
272 | UCB_PR_ADDR (ucbp) = selfrel_offset31 (ucbp->pr_cache.ehtp); | |
273 | } | |
274 | return _URC_OK; | |
275 | } | |
276 | ||
277 | ||
278 | /* Perform phase2 unwinding. VRS is the initial virtual register state. */ | |
279 | ||
280 | static void __attribute__((noreturn)) | |
281 | unwind_phase2 (_Unwind_Control_Block * ucbp, phase2_vrs * vrs) | |
282 | { | |
283 | _Unwind_Reason_Code pr_result; | |
284 | ||
285 | do | |
286 | { | |
287 | /* Find the entry for this routine. */ | |
288 | if (get_eit_entry (ucbp, VRS_PC(vrs)) != _URC_OK) | |
289 | abort (); | |
290 | ||
291 | UCB_SAVED_CALLSITE_ADDR (ucbp) = VRS_PC(vrs); | |
292 | ||
293 | /* Call the pr to decide what to do. */ | |
294 | pr_result = ((personality_routine) UCB_PR_ADDR (ucbp)) | |
295 | (_US_UNWIND_FRAME_STARTING, ucbp, (_Unwind_Context *) vrs); | |
296 | } | |
297 | while (pr_result == _URC_CONTINUE_UNWIND); | |
298 | ||
299 | if (pr_result != _URC_INSTALL_CONTEXT) | |
300 | abort(); | |
69048898 SDJ |
301 | |
302 | uw_restore_core_regs (vrs, &vrs->core); | |
1e874273 PB |
303 | } |
304 | ||
305 | /* Perform phase2 forced unwinding. */ | |
306 | ||
307 | static _Unwind_Reason_Code | |
308 | unwind_phase2_forced (_Unwind_Control_Block *ucbp, phase2_vrs *entry_vrs, | |
309 | int resuming) | |
310 | { | |
311 | _Unwind_Stop_Fn stop_fn = (_Unwind_Stop_Fn) UCB_FORCED_STOP_FN (ucbp); | |
312 | void *stop_arg = (void *)UCB_FORCED_STOP_ARG (ucbp); | |
313 | _Unwind_Reason_Code pr_result = 0; | |
314 | /* We use phase1_vrs here even though we do not demand save, for the | |
315 | prev_sp field. */ | |
316 | phase1_vrs saved_vrs, next_vrs; | |
317 | ||
318 | /* Save the core registers. */ | |
319 | saved_vrs.core = entry_vrs->core; | |
320 | /* We don't need to demand-save the non-core registers, because we | |
321 | unwind in a single pass. */ | |
322 | saved_vrs.demand_save_flags = 0; | |
323 | ||
324 | /* Unwind until we reach a propagation barrier. */ | |
325 | do | |
326 | { | |
327 | _Unwind_State action; | |
328 | _Unwind_Reason_Code entry_code; | |
329 | _Unwind_Reason_Code stop_code; | |
330 | ||
331 | /* Find the entry for this routine. */ | |
332 | entry_code = get_eit_entry (ucbp, VRS_PC (&saved_vrs)); | |
333 | ||
334 | if (resuming) | |
335 | { | |
336 | action = _US_UNWIND_FRAME_RESUME | _US_FORCE_UNWIND; | |
337 | resuming = 0; | |
338 | } | |
339 | else | |
340 | action = _US_UNWIND_FRAME_STARTING | _US_FORCE_UNWIND; | |
341 | ||
342 | if (entry_code == _URC_OK) | |
343 | { | |
344 | UCB_SAVED_CALLSITE_ADDR (ucbp) = VRS_PC (&saved_vrs); | |
345 | ||
346 | next_vrs = saved_vrs; | |
347 | ||
348 | /* Call the pr to decide what to do. */ | |
349 | pr_result = ((personality_routine) UCB_PR_ADDR (ucbp)) | |
350 | (action, ucbp, (void *) &next_vrs); | |
351 | ||
352 | saved_vrs.prev_sp = VRS_SP (&next_vrs); | |
353 | } | |
354 | else | |
355 | { | |
356 | /* Treat any failure as the end of unwinding, to cope more | |
357 | gracefully with missing EH information. Mixed EH and | |
358 | non-EH within one object will usually result in failure, | |
359 | because the .ARM.exidx tables do not indicate the end | |
360 | of the code to which they apply; but mixed EH and non-EH | |
361 | shared objects should return an unwind failure at the | |
362 | entry of a non-EH shared object. */ | |
363 | action |= _US_END_OF_STACK; | |
364 | ||
365 | saved_vrs.prev_sp = VRS_SP (&saved_vrs); | |
366 | } | |
367 | ||
368 | stop_code = stop_fn (1, action, ucbp->exception_class, ucbp, | |
369 | (void *)&saved_vrs, stop_arg); | |
370 | if (stop_code != _URC_NO_REASON) | |
371 | return _URC_FAILURE; | |
372 | ||
373 | if (entry_code != _URC_OK) | |
374 | return entry_code; | |
375 | ||
376 | saved_vrs = next_vrs; | |
377 | } | |
378 | while (pr_result == _URC_CONTINUE_UNWIND); | |
379 | ||
380 | if (pr_result != _URC_INSTALL_CONTEXT) | |
381 | { | |
382 | /* Some sort of failure has occurred in the pr and probably the | |
383 | pr returned _URC_FAILURE. */ | |
384 | return _URC_FAILURE; | |
385 | } | |
386 | ||
69048898 | 387 | uw_restore_core_regs (&saved_vrs, &saved_vrs.core); |
1e874273 PB |
388 | } |
389 | ||
390 | /* This is a very limited implementation of _Unwind_GetCFA. It returns | |
391 | the stack pointer as it is about to be unwound, and is only valid | |
392 | while calling the stop function during forced unwinding. If the | |
393 | current personality routine result is going to run a cleanup, this | |
394 | will not be the CFA; but when the frame is really unwound, it will | |
395 | be. */ | |
396 | ||
397 | _Unwind_Word | |
398 | _Unwind_GetCFA (_Unwind_Context *context) | |
399 | { | |
400 | return ((phase1_vrs *) context)->prev_sp; | |
401 | } | |
402 | ||
403 | /* Perform phase1 unwinding. UCBP is the exception being thrown, and | |
404 | entry_VRS is the register state on entry to _Unwind_RaiseException. */ | |
405 | ||
406 | _Unwind_Reason_Code | |
407 | __gnu_Unwind_RaiseException (_Unwind_Control_Block *, phase2_vrs *); | |
408 | ||
409 | _Unwind_Reason_Code | |
410 | __gnu_Unwind_RaiseException (_Unwind_Control_Block * ucbp, | |
411 | phase2_vrs * entry_vrs) | |
412 | { | |
413 | phase1_vrs saved_vrs; | |
414 | _Unwind_Reason_Code pr_result; | |
415 | ||
416 | /* Set the pc to the call site. */ | |
417 | VRS_PC (entry_vrs) = VRS_RETURN(entry_vrs); | |
418 | ||
419 | /* Save the core registers. */ | |
420 | saved_vrs.core = entry_vrs->core; | |
421 | /* Set demand-save flags. */ | |
422 | saved_vrs.demand_save_flags = ~(_uw) 0; | |
423 | ||
424 | /* Unwind until we reach a propagation barrier. */ | |
425 | do | |
426 | { | |
427 | /* Find the entry for this routine. */ | |
428 | if (get_eit_entry (ucbp, VRS_PC (&saved_vrs)) != _URC_OK) | |
429 | return _URC_FAILURE; | |
430 | ||
431 | /* Call the pr to decide what to do. */ | |
432 | pr_result = ((personality_routine) UCB_PR_ADDR (ucbp)) | |
433 | (_US_VIRTUAL_UNWIND_FRAME, ucbp, (void *) &saved_vrs); | |
434 | } | |
435 | while (pr_result == _URC_CONTINUE_UNWIND); | |
436 | ||
437 | /* We've unwound as far as we want to go, so restore the original | |
438 | register state. */ | |
439 | restore_non_core_regs (&saved_vrs); | |
440 | if (pr_result != _URC_HANDLER_FOUND) | |
441 | { | |
442 | /* Some sort of failure has occurred in the pr and probably the | |
443 | pr returned _URC_FAILURE. */ | |
444 | return _URC_FAILURE; | |
445 | } | |
446 | ||
447 | unwind_phase2 (ucbp, entry_vrs); | |
448 | } | |
449 | ||
450 | /* Resume unwinding after a cleanup has been run. UCBP is the exception | |
451 | being thrown and ENTRY_VRS is the register state on entry to | |
452 | _Unwind_Resume. */ | |
453 | _Unwind_Reason_Code | |
454 | __gnu_Unwind_ForcedUnwind (_Unwind_Control_Block *, | |
455 | _Unwind_Stop_Fn, void *, phase2_vrs *); | |
456 | ||
457 | _Unwind_Reason_Code | |
458 | __gnu_Unwind_ForcedUnwind (_Unwind_Control_Block *ucbp, | |
459 | _Unwind_Stop_Fn stop_fn, void *stop_arg, | |
460 | phase2_vrs *entry_vrs) | |
461 | { | |
462 | UCB_FORCED_STOP_FN (ucbp) = (_uw) stop_fn; | |
463 | UCB_FORCED_STOP_ARG (ucbp) = (_uw) stop_arg; | |
464 | ||
465 | /* Set the pc to the call site. */ | |
466 | VRS_PC (entry_vrs) = VRS_RETURN(entry_vrs); | |
467 | ||
468 | return unwind_phase2_forced (ucbp, entry_vrs, 0); | |
469 | } | |
470 | ||
471 | _Unwind_Reason_Code | |
472 | __gnu_Unwind_Resume (_Unwind_Control_Block *, phase2_vrs *); | |
473 | ||
474 | _Unwind_Reason_Code | |
475 | __gnu_Unwind_Resume (_Unwind_Control_Block * ucbp, phase2_vrs * entry_vrs) | |
476 | { | |
477 | _Unwind_Reason_Code pr_result; | |
478 | ||
479 | /* Recover the saved address. */ | |
480 | VRS_PC (entry_vrs) = UCB_SAVED_CALLSITE_ADDR (ucbp); | |
481 | ||
482 | if (UCB_FORCED_STOP_FN (ucbp)) | |
483 | { | |
484 | unwind_phase2_forced (ucbp, entry_vrs, 1); | |
485 | ||
486 | /* We can't return failure at this point. */ | |
487 | abort (); | |
488 | } | |
489 | ||
490 | /* Call the cached PR. */ | |
491 | pr_result = ((personality_routine) UCB_PR_ADDR (ucbp)) | |
492 | (_US_UNWIND_FRAME_RESUME, ucbp, (_Unwind_Context *) entry_vrs); | |
493 | ||
494 | switch (pr_result) | |
495 | { | |
496 | case _URC_INSTALL_CONTEXT: | |
497 | /* Upload the registers to enter the landing pad. */ | |
69048898 | 498 | uw_restore_core_regs (entry_vrs, &entry_vrs->core); |
1e874273 PB |
499 | |
500 | case _URC_CONTINUE_UNWIND: | |
501 | /* Continue unwinding the next frame. */ | |
502 | unwind_phase2 (ucbp, entry_vrs); | |
503 | ||
504 | default: | |
505 | abort (); | |
506 | } | |
507 | } | |
508 | ||
509 | _Unwind_Reason_Code | |
510 | __gnu_Unwind_Resume_or_Rethrow (_Unwind_Control_Block *, phase2_vrs *); | |
511 | ||
512 | _Unwind_Reason_Code | |
513 | __gnu_Unwind_Resume_or_Rethrow (_Unwind_Control_Block * ucbp, | |
514 | phase2_vrs * entry_vrs) | |
515 | { | |
516 | if (!UCB_FORCED_STOP_FN (ucbp)) | |
517 | return __gnu_Unwind_RaiseException (ucbp, entry_vrs); | |
518 | ||
519 | /* Set the pc to the call site. */ | |
520 | VRS_PC (entry_vrs) = VRS_RETURN (entry_vrs); | |
521 | /* Continue unwinding the next frame. */ | |
522 | return unwind_phase2_forced (ucbp, entry_vrs, 0); | |
523 | } | |
524 | ||
525 | /* Clean up an exception object when unwinding is complete. */ | |
526 | void | |
527 | _Unwind_Complete (_Unwind_Control_Block * ucbp __attribute__((unused))) | |
528 | { | |
529 | } | |
530 | ||
531 | ||
532 | /* Free an exception. */ | |
533 | ||
534 | void | |
535 | _Unwind_DeleteException (_Unwind_Exception * exc) | |
536 | { | |
537 | if (exc->exception_cleanup) | |
538 | (*exc->exception_cleanup) (_URC_FOREIGN_EXCEPTION_CAUGHT, exc); | |
539 | } | |
540 | ||
541 | ||
542 | /* Perform stack backtrace through unwind data. */ | |
543 | _Unwind_Reason_Code | |
544 | __gnu_Unwind_Backtrace(_Unwind_Trace_Fn trace, void * trace_argument, | |
545 | phase2_vrs * entry_vrs); | |
546 | _Unwind_Reason_Code | |
547 | __gnu_Unwind_Backtrace(_Unwind_Trace_Fn trace, void * trace_argument, | |
548 | phase2_vrs * entry_vrs) | |
549 | { | |
550 | phase1_vrs saved_vrs; | |
551 | _Unwind_Reason_Code code; | |
552 | ||
553 | _Unwind_Control_Block ucb; | |
554 | _Unwind_Control_Block *ucbp = &ucb; | |
555 | ||
556 | /* Set the pc to the call site. */ | |
557 | VRS_PC (entry_vrs) = VRS_RETURN (entry_vrs); | |
558 | ||
559 | /* Save the core registers. */ | |
560 | saved_vrs.core = entry_vrs->core; | |
561 | /* Set demand-save flags. */ | |
562 | saved_vrs.demand_save_flags = ~(_uw) 0; | |
563 | ||
564 | do | |
565 | { | |
566 | /* Find the entry for this routine. */ | |
567 | if (get_eit_entry (ucbp, VRS_PC (&saved_vrs)) != _URC_OK) | |
568 | { | |
569 | code = _URC_FAILURE; | |
570 | break; | |
571 | } | |
572 | ||
573 | /* The dwarf unwinder assumes the context structure holds things | |
574 | like the function and LSDA pointers. The ARM implementation | |
575 | caches these in the exception header (UCB). To avoid | |
576 | rewriting everything we make the virtual IP register point at | |
577 | the UCB. */ | |
578 | _Unwind_SetGR((_Unwind_Context *)&saved_vrs, UNWIND_POINTER_REG, (_Unwind_Ptr) ucbp); | |
579 | ||
580 | /* Call trace function. */ | |
581 | if ((*trace) ((_Unwind_Context *) &saved_vrs, trace_argument) | |
582 | != _URC_NO_REASON) | |
583 | { | |
584 | code = _URC_FAILURE; | |
585 | break; | |
586 | } | |
587 | ||
588 | /* Call the pr to decide what to do. */ | |
589 | code = ((personality_routine) UCB_PR_ADDR (ucbp)) | |
590 | (_US_VIRTUAL_UNWIND_FRAME | _US_FORCE_UNWIND, | |
591 | ucbp, (void *) &saved_vrs); | |
592 | } | |
593 | while (code != _URC_END_OF_STACK | |
594 | && code != _URC_FAILURE); | |
595 | ||
596 | restore_non_core_regs (&saved_vrs); | |
597 | return code; | |
598 | } | |
599 | ||
600 | ||
601 | /* Common implementation for ARM ABI defined personality routines. | |
602 | ID is the index of the personality routine, other arguments are as defined | |
603 | by __aeabi_unwind_cpp_pr{0,1,2}. */ | |
604 | ||
605 | static _Unwind_Reason_Code | |
606 | __gnu_unwind_pr_common (_Unwind_State state, | |
607 | _Unwind_Control_Block *ucbp, | |
608 | _Unwind_Context *context, | |
609 | int id) | |
610 | { | |
611 | __gnu_unwind_state uws; | |
612 | _uw *data; | |
613 | _uw offset; | |
614 | _uw len; | |
615 | _uw rtti_count; | |
616 | int phase2_call_unexpected_after_unwind = 0; | |
617 | int in_range = 0; | |
618 | int forced_unwind = state & _US_FORCE_UNWIND; | |
619 | ||
620 | state &= _US_ACTION_MASK; | |
621 | ||
622 | data = (_uw *) ucbp->pr_cache.ehtp; | |
623 | uws.data = *(data++); | |
624 | uws.next = data; | |
625 | if (id == 0) | |
626 | { | |
627 | uws.data <<= 8; | |
628 | uws.words_left = 0; | |
629 | uws.bytes_left = 3; | |
630 | } | |
56dc349e | 631 | else if (id < 3) |
1e874273 PB |
632 | { |
633 | uws.words_left = (uws.data >> 16) & 0xff; | |
634 | uws.data <<= 16; | |
635 | uws.bytes_left = 2; | |
636 | data += uws.words_left; | |
637 | } | |
638 | ||
639 | /* Restore the saved pointer. */ | |
640 | if (state == _US_UNWIND_FRAME_RESUME) | |
641 | data = (_uw *) ucbp->cleanup_cache.bitpattern[0]; | |
642 | ||
643 | if ((ucbp->pr_cache.additional & 1) == 0) | |
644 | { | |
645 | /* Process descriptors. */ | |
646 | while (*data) | |
647 | { | |
648 | _uw addr; | |
649 | _uw fnstart; | |
650 | ||
651 | if (id == 2) | |
652 | { | |
653 | len = ((EHT32 *) data)->length; | |
654 | offset = ((EHT32 *) data)->offset; | |
655 | data += 2; | |
656 | } | |
657 | else | |
658 | { | |
659 | len = ((EHT16 *) data)->length; | |
660 | offset = ((EHT16 *) data)->offset; | |
661 | data++; | |
662 | } | |
663 | ||
664 | fnstart = ucbp->pr_cache.fnstart + (offset & ~1); | |
665 | addr = _Unwind_GetGR (context, R_PC); | |
666 | in_range = (fnstart <= addr && addr < fnstart + (len & ~1)); | |
667 | ||
668 | switch (((offset & 1) << 1) | (len & 1)) | |
669 | { | |
670 | case 0: | |
671 | /* Cleanup. */ | |
672 | if (state != _US_VIRTUAL_UNWIND_FRAME | |
673 | && in_range) | |
674 | { | |
675 | /* Cleanup in range, and we are running cleanups. */ | |
676 | _uw lp; | |
677 | ||
678 | /* Landing pad address is 31-bit pc-relative offset. */ | |
679 | lp = selfrel_offset31 (data); | |
680 | data++; | |
681 | /* Save the exception data pointer. */ | |
682 | ucbp->cleanup_cache.bitpattern[0] = (_uw) data; | |
683 | if (!__cxa_begin_cleanup (ucbp)) | |
684 | return _URC_FAILURE; | |
685 | /* Setup the VRS to enter the landing pad. */ | |
686 | _Unwind_SetGR (context, R_PC, lp); | |
687 | return _URC_INSTALL_CONTEXT; | |
688 | } | |
689 | /* Cleanup not in range, or we are in stage 1. */ | |
690 | data++; | |
691 | break; | |
692 | ||
693 | case 1: | |
694 | /* Catch handler. */ | |
695 | if (state == _US_VIRTUAL_UNWIND_FRAME) | |
696 | { | |
697 | if (in_range) | |
698 | { | |
699 | /* Check for a barrier. */ | |
700 | _uw rtti; | |
701 | bool is_reference = (data[0] & uint32_highbit) != 0; | |
702 | void *matched; | |
703 | enum __cxa_type_match_result match_type; | |
704 | ||
705 | /* Check for no-throw areas. */ | |
706 | if (data[1] == (_uw) -2) | |
707 | return _URC_FAILURE; | |
708 | ||
709 | /* The thrown object immediately follows the ECB. */ | |
710 | matched = (void *)(ucbp + 1); | |
711 | if (data[1] != (_uw) -1) | |
712 | { | |
713 | /* Match a catch specification. */ | |
714 | rtti = _Unwind_decode_typeinfo_ptr (0, | |
715 | (_uw) &data[1]); | |
716 | match_type = __cxa_type_match (ucbp, | |
717 | (type_info *) rtti, | |
718 | is_reference, | |
719 | &matched); | |
720 | } | |
721 | else | |
722 | match_type = ctm_succeeded; | |
723 | ||
724 | if (match_type) | |
725 | { | |
726 | ucbp->barrier_cache.sp = | |
727 | _Unwind_GetGR (context, R_SP); | |
728 | // ctm_succeeded_with_ptr_to_base really | |
729 | // means _c_t_m indirected the pointer | |
730 | // object. We have to reconstruct the | |
731 | // additional pointer layer by using a temporary. | |
732 | if (match_type == ctm_succeeded_with_ptr_to_base) | |
733 | { | |
734 | ucbp->barrier_cache.bitpattern[2] | |
735 | = (_uw) matched; | |
736 | ucbp->barrier_cache.bitpattern[0] | |
737 | = (_uw) &ucbp->barrier_cache.bitpattern[2]; | |
738 | } | |
739 | else | |
740 | ucbp->barrier_cache.bitpattern[0] = (_uw) matched; | |
741 | ucbp->barrier_cache.bitpattern[1] = (_uw) data; | |
742 | return _URC_HANDLER_FOUND; | |
743 | } | |
744 | } | |
745 | /* Handler out of range, or not matched. */ | |
746 | } | |
747 | else if (ucbp->barrier_cache.sp == _Unwind_GetGR (context, R_SP) | |
748 | && ucbp->barrier_cache.bitpattern[1] == (_uw) data) | |
749 | { | |
750 | /* Matched a previous propagation barrier. */ | |
751 | _uw lp; | |
752 | ||
753 | /* Setup for entry to the handler. */ | |
754 | lp = selfrel_offset31 (data); | |
755 | _Unwind_SetGR (context, R_PC, lp); | |
756 | _Unwind_SetGR (context, 0, (_uw) ucbp); | |
757 | return _URC_INSTALL_CONTEXT; | |
758 | } | |
759 | /* Catch handler not matched. Advance to the next descriptor. */ | |
760 | data += 2; | |
761 | break; | |
762 | ||
763 | case 2: | |
764 | rtti_count = data[0] & 0x7fffffff; | |
765 | /* Exception specification. */ | |
766 | if (state == _US_VIRTUAL_UNWIND_FRAME) | |
767 | { | |
768 | if (in_range && (!forced_unwind || !rtti_count)) | |
769 | { | |
770 | /* Match against the exception specification. */ | |
771 | _uw i; | |
772 | _uw rtti; | |
773 | void *matched; | |
774 | ||
775 | for (i = 0; i < rtti_count; i++) | |
776 | { | |
777 | matched = (void *)(ucbp + 1); | |
778 | rtti = _Unwind_decode_typeinfo_ptr (0, | |
779 | (_uw) &data[i + 1]); | |
780 | if (__cxa_type_match (ucbp, (type_info *) rtti, 0, | |
781 | &matched)) | |
782 | break; | |
783 | } | |
784 | ||
785 | if (i == rtti_count) | |
786 | { | |
787 | /* Exception does not match the spec. */ | |
788 | ucbp->barrier_cache.sp = | |
789 | _Unwind_GetGR (context, R_SP); | |
790 | ucbp->barrier_cache.bitpattern[0] = (_uw) matched; | |
791 | ucbp->barrier_cache.bitpattern[1] = (_uw) data; | |
792 | return _URC_HANDLER_FOUND; | |
793 | } | |
794 | } | |
795 | /* Handler out of range, or exception is permitted. */ | |
796 | } | |
797 | else if (ucbp->barrier_cache.sp == _Unwind_GetGR (context, R_SP) | |
798 | && ucbp->barrier_cache.bitpattern[1] == (_uw) data) | |
799 | { | |
800 | /* Matched a previous propagation barrier. */ | |
801 | _uw lp; | |
802 | /* Record the RTTI list for __cxa_call_unexpected. */ | |
803 | ucbp->barrier_cache.bitpattern[1] = rtti_count; | |
804 | ucbp->barrier_cache.bitpattern[2] = 0; | |
805 | ucbp->barrier_cache.bitpattern[3] = 4; | |
806 | ucbp->barrier_cache.bitpattern[4] = (_uw) &data[1]; | |
807 | ||
808 | if (data[0] & uint32_highbit) | |
809 | { | |
810 | data += rtti_count + 1; | |
811 | /* Setup for entry to the handler. */ | |
812 | lp = selfrel_offset31 (data); | |
813 | data++; | |
814 | _Unwind_SetGR (context, R_PC, lp); | |
815 | _Unwind_SetGR (context, 0, (_uw) ucbp); | |
816 | return _URC_INSTALL_CONTEXT; | |
817 | } | |
818 | else | |
819 | phase2_call_unexpected_after_unwind = 1; | |
820 | } | |
821 | if (data[0] & uint32_highbit) | |
822 | data++; | |
823 | data += rtti_count + 1; | |
824 | break; | |
825 | ||
826 | default: | |
827 | /* Should never happen. */ | |
828 | return _URC_FAILURE; | |
829 | } | |
830 | /* Finished processing this descriptor. */ | |
831 | } | |
832 | } | |
833 | ||
834 | if (id >= 3) | |
835 | { | |
836 | /* 24-bit ecoding */ | |
837 | if (__gnu_unwind_24bit (context, uws.data, id == 4) != _URC_OK) | |
838 | return _URC_FAILURE; | |
839 | } | |
840 | else | |
841 | { | |
842 | if (__gnu_unwind_execute (context, &uws) != _URC_OK) | |
843 | return _URC_FAILURE; | |
844 | } | |
845 | ||
846 | if (phase2_call_unexpected_after_unwind) | |
847 | { | |
848 | /* Enter __cxa_unexpected as if called from the call site. */ | |
849 | _Unwind_SetGR (context, R_LR, _Unwind_GetGR (context, R_PC)); | |
850 | _Unwind_SetGR (context, R_PC, (_uw) &__cxa_call_unexpected); | |
851 | return _URC_INSTALL_CONTEXT; | |
852 | } | |
853 | ||
854 | return _URC_CONTINUE_UNWIND; | |
855 | } |