1//===--------------------------- Unwind-EHABI.cpp -------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//
8// Implements ARM zero-cost C++ exceptions
9//
10//===----------------------------------------------------------------------===//
11
12#include "Unwind-EHABI.h"
13
14#if defined(_LIBUNWIND_ARM_EHABI)
15
16#include <inttypes.h>
17#include <stdbool.h>
18#include <stdint.h>
19#include <stdio.h>
20#include <stdlib.h>
21#include <string.h>
22
23#include "config.h"
24#include "libunwind.h"
25#include "libunwind_ext.h"
26#include "unwind.h"
27
28namespace {
29
30// Strange order: take words in order, but inside word, take from most to least
31// signinficant byte.
32uint8_t getByte(const uint32_t* data, size_t offset) {
33 const uint8_t* byteData = reinterpret_cast<const uint8_t*>(data);
34 return byteData[(offset & ~(size_t)0x03) + (3 - (offset & (size_t)0x03))];
35}
36
37const char* getNextWord(const char* data, uint32_t* out) {
38 *out = *reinterpret_cast<const uint32_t*>(data);
39 return data + 4;
40}
41
42const char* getNextNibble(const char* data, uint32_t* out) {
43 *out = *reinterpret_cast<const uint16_t*>(data);
44 return data + 2;
45}
46
47struct Descriptor {
48 // See # 9.2
49 typedef enum {
50 SU16 = 0, // Short descriptor, 16-bit entries
51 LU16 = 1, // Long descriptor, 16-bit entries
52 LU32 = 3, // Long descriptor, 32-bit entries
53 RESERVED0 = 4, RESERVED1 = 5, RESERVED2 = 6, RESERVED3 = 7,
54 RESERVED4 = 8, RESERVED5 = 9, RESERVED6 = 10, RESERVED7 = 11,
55 RESERVED8 = 12, RESERVED9 = 13, RESERVED10 = 14, RESERVED11 = 15
56 } Format;
57
58 // See # 9.2
59 typedef enum {
60 CLEANUP = 0x0,
61 FUNC = 0x1,
62 CATCH = 0x2,
63 INVALID = 0x4
64 } Kind;
65};
66
67_Unwind_Reason_Code ProcessDescriptors(
68 _Unwind_State state,
69 _Unwind_Control_Block* ucbp,
70 struct _Unwind_Context* context,
71 Descriptor::Format format,
72 const char* descriptorStart,
73 uint32_t flags) {
74
75 // EHT is inlined in the index using compact form. No descriptors. #5
76 if (flags & 0x1)
77 return _URC_CONTINUE_UNWIND;
78
79 // TODO: We should check the state here, and determine whether we need to
80 // perform phase1 or phase2 unwinding.
81 (void)state;
82
83 const char* descriptor = descriptorStart;
84 uint32_t descriptorWord;
85 getNextWord(descriptor, &descriptorWord);
86 while (descriptorWord) {
87 // Read descriptor based on # 9.2.
88 uint32_t length;
89 uint32_t offset;
90 switch (format) {
91 case Descriptor::LU32:
92 descriptor = getNextWord(descriptor, &length);
93 descriptor = getNextWord(descriptor, &offset);
94 case Descriptor::LU16:
95 descriptor = getNextNibble(descriptor, &length);
96 descriptor = getNextNibble(descriptor, &offset);
97 default:
98 assert(false);
99 return _URC_FAILURE;
100 }
101
102 // See # 9.2 table for decoding the kind of descriptor. It's a 2-bit value.
103 Descriptor::Kind kind =
104 static_cast<Descriptor::Kind>((length & 0x1) | ((offset & 0x1) << 1));
105
106 // Clear off flag from last bit.
107 length &= ~1u;
108 offset &= ~1u;
109 uintptr_t scopeStart = ucbp->pr_cache.fnstart + offset;
110 uintptr_t scopeEnd = scopeStart + length;
111 uintptr_t pc = _Unwind_GetIP(context);
112 bool isInScope = (scopeStart <= pc) && (pc < scopeEnd);
113
114 switch (kind) {
115 case Descriptor::CLEANUP: {
116 // TODO(ajwong): Handle cleanup descriptors.
117 break;
118 }
119 case Descriptor::FUNC: {
120 // TODO(ajwong): Handle function descriptors.
121 break;
122 }
123 case Descriptor::CATCH: {
124 // Catch descriptors require gobbling one more word.
125 uint32_t landing_pad;
126 descriptor = getNextWord(descriptor, &landing_pad);
127
128 if (isInScope) {
129 // TODO(ajwong): This is only phase1 compatible logic. Implement
130 // phase2.
131 landing_pad = signExtendPrel31(landing_pad & ~0x80000000);
132 if (landing_pad == 0xffffffff) {
133 return _URC_HANDLER_FOUND;
134 } else if (landing_pad == 0xfffffffe) {
135 return _URC_FAILURE;
136 } else {
137 /*
138 bool is_reference_type = landing_pad & 0x80000000;
139 void* matched_object;
140 if (__cxxabiv1::__cxa_type_match(
141 ucbp, reinterpret_cast<const std::type_info *>(landing_pad),
142 is_reference_type,
143 &matched_object) != __cxxabiv1::ctm_failed)
144 return _URC_HANDLER_FOUND;
145 */
146 _LIBUNWIND_ABORT("Type matching not implemented");
147 }
148 }
149 break;
150 }
151 default:
152 _LIBUNWIND_ABORT("Invalid descriptor kind found.");
153 }
154
155 getNextWord(descriptor, &descriptorWord);
156 }
157
158 return _URC_CONTINUE_UNWIND;
159}
160
161static _Unwind_Reason_Code unwindOneFrame(_Unwind_State state,
162 _Unwind_Control_Block* ucbp,
163 struct _Unwind_Context* context) {
164 // Read the compact model EHT entry's header # 6.3
165 const uint32_t* unwindingData = ucbp->pr_cache.ehtp;
166 assert((*unwindingData & 0xf0000000) == 0x80000000 && "Must be a compact entry");
167 Descriptor::Format format =
168 static_cast<Descriptor::Format>((*unwindingData & 0x0f000000) >> 24);
169
170 const char *lsda =
171 reinterpret_cast<const char *>(_Unwind_GetLanguageSpecificData(context));
172
173 // Handle descriptors before unwinding so they are processed in the context
174 // of the correct stack frame.
175 _Unwind_Reason_Code result =
176 ProcessDescriptors(state, ucbp, context, format, lsda,
177 ucbp->pr_cache.additional);
178
179 if (result != _URC_CONTINUE_UNWIND)
180 return result;
181
182 if (__unw_step(reinterpret_cast<unw_cursor_t *>(context)) != UNW_STEP_SUCCESS)
183 return _URC_FAILURE;
184 return _URC_CONTINUE_UNWIND;
185}
186
187// Generates mask discriminator for _Unwind_VRS_Pop, e.g. for _UVRSC_CORE /
188// _UVRSD_UINT32.
189uint32_t RegisterMask(uint8_t start, uint8_t count_minus_one) {
190 return ((1U << (count_minus_one + 1)) - 1) << start;
191}
192
193// Generates mask discriminator for _Unwind_VRS_Pop, e.g. for _UVRSC_VFP /
194// _UVRSD_DOUBLE.
195uint32_t RegisterRange(uint8_t start, uint8_t count_minus_one) {
196 return ((uint32_t)start << 16) | ((uint32_t)count_minus_one + 1);
197}
198
199} // end anonymous namespace
200
201/**
202 * Decodes an EHT entry.
203 *
204 * @param data Pointer to EHT.
205 * @param[out] off Offset from return value (in bytes) to begin interpretation.
206 * @param[out] len Number of bytes in unwind code.
207 * @return Pointer to beginning of unwind code.
208 */
209extern "C" const uint32_t*
210decode_eht_entry(const uint32_t* data, size_t* off, size_t* len) {
211 if ((*data & 0x80000000) == 0) {
212 // 6.2: Generic Model
213 //
214 // EHT entry is a prel31 pointing to the PR, followed by data understood
215 // only by the personality routine. Fortunately, all existing assembler
216 // implementations, including GNU assembler, LLVM integrated assembler,
217 // and ARM assembler, assume that the unwind opcodes come after the
218 // personality rountine address.
219 *off = 1; // First byte is size data.
220 *len = (((data[1] >> 24) & 0xff) + 1) * 4;
221 data++; // Skip the first word, which is the prel31 offset.
222 } else {
223 // 6.3: ARM Compact Model
224 //
225 // EHT entries here correspond to the __aeabi_unwind_cpp_pr[012] PRs indeded
226 // by format:
227 Descriptor::Format format =
228 static_cast<Descriptor::Format>((*data & 0x0f000000) >> 24);
229 switch (format) {
230 case Descriptor::SU16:
231 *len = 4;
232 *off = 1;
233 break;
234 case Descriptor::LU16:
235 case Descriptor::LU32:
236 *len = 4 + 4 * ((*data & 0x00ff0000) >> 16);
237 *off = 2;
238 break;
239 default:
240 return nullptr;
241 }
242 }
243 return data;
244}
245
246_LIBUNWIND_EXPORT _Unwind_Reason_Code
247_Unwind_VRS_Interpret(_Unwind_Context *context, const uint32_t *data,
248 size_t offset, size_t len) {
249 bool wrotePC = false;
250 bool finish = false;
251 while (offset < len && !finish) {
252 uint8_t byte = getByte(data, offset++);
253 if ((byte & 0x80) == 0) {
254 uint32_t sp;
255 _Unwind_VRS_Get(context, _UVRSC_CORE, UNW_ARM_SP, _UVRSD_UINT32, &sp);
256 if (byte & 0x40)
257 sp -= (((uint32_t)byte & 0x3f) << 2) + 4;
258 else
259 sp += ((uint32_t)byte << 2) + 4;
260 _Unwind_VRS_Set(context, _UVRSC_CORE, UNW_ARM_SP, _UVRSD_UINT32, &sp);
261 } else {
262 switch (byte & 0xf0) {
263 case 0x80: {
264 if (offset >= len)
265 return _URC_FAILURE;
266 uint32_t registers =
267 (((uint32_t)byte & 0x0f) << 12) |
268 (((uint32_t)getByte(data, offset++)) << 4);
269 if (!registers)
270 return _URC_FAILURE;
271 if (registers & (1 << 15))
272 wrotePC = true;
273 _Unwind_VRS_Pop(context, _UVRSC_CORE, registers, _UVRSD_UINT32);
274 break;
275 }
276 case 0x90: {
277 uint8_t reg = byte & 0x0f;
278 if (reg == 13 || reg == 15)
279 return _URC_FAILURE;
280 uint32_t sp;
281 _Unwind_VRS_Get(context, _UVRSC_CORE, UNW_ARM_R0 + reg,
282 _UVRSD_UINT32, &sp);
283 _Unwind_VRS_Set(context, _UVRSC_CORE, UNW_ARM_SP, _UVRSD_UINT32,
284 &sp);
285 break;
286 }
287 case 0xa0: {
288 uint32_t registers = RegisterMask(4, byte & 0x07);
289 if (byte & 0x08)
290 registers |= 1 << 14;
291 _Unwind_VRS_Pop(context, _UVRSC_CORE, registers, _UVRSD_UINT32);
292 break;
293 }
294 case 0xb0: {
295 switch (byte) {
296 case 0xb0:
297 finish = true;
298 break;
299 case 0xb1: {
300 if (offset >= len)
301 return _URC_FAILURE;
302 uint8_t registers = getByte(data, offset++);
303 if (registers & 0xf0 || !registers)
304 return _URC_FAILURE;
305 _Unwind_VRS_Pop(context, _UVRSC_CORE, registers, _UVRSD_UINT32);
306 break;
307 }
308 case 0xb2: {
309 uint32_t addend = 0;
310 uint32_t shift = 0;
311 // This decodes a uleb128 value.
312 while (true) {
313 if (offset >= len)
314 return _URC_FAILURE;
315 uint32_t v = getByte(data, offset++);
316 addend |= (v & 0x7f) << shift;
317 if ((v & 0x80) == 0)
318 break;
319 shift += 7;
320 }
321 uint32_t sp;
322 _Unwind_VRS_Get(context, _UVRSC_CORE, UNW_ARM_SP, _UVRSD_UINT32,
323 &sp);
324 sp += 0x204 + (addend << 2);
325 _Unwind_VRS_Set(context, _UVRSC_CORE, UNW_ARM_SP, _UVRSD_UINT32,
326 &sp);
327 break;
328 }
329 case 0xb3: {
330 uint8_t v = getByte(data, offset++);
331 _Unwind_VRS_Pop(context, _UVRSC_VFP,
332 RegisterRange(static_cast<uint8_t>(v >> 4),
333 v & 0x0f), _UVRSD_VFPX);
334 break;
335 }
336 case 0xb4:
337 case 0xb5:
338 case 0xb6:
339 case 0xb7:
340 return _URC_FAILURE;
341 default:
342 _Unwind_VRS_Pop(context, _UVRSC_VFP,
343 RegisterRange(8, byte & 0x07), _UVRSD_VFPX);
344 break;
345 }
346 break;
347 }
348 case 0xc0: {
349 switch (byte) {
350#if defined(__ARM_WMMX)
351 case 0xc0:
352 case 0xc1:
353 case 0xc2:
354 case 0xc3:
355 case 0xc4:
356 case 0xc5:
357 _Unwind_VRS_Pop(context, _UVRSC_WMMXD,
358 RegisterRange(10, byte & 0x7), _UVRSD_DOUBLE);
359 break;
360 case 0xc6: {
361 uint8_t v = getByte(data, offset++);
362 uint8_t start = static_cast<uint8_t>(v >> 4);
363 uint8_t count_minus_one = v & 0xf;
364 if (start + count_minus_one >= 16)
365 return _URC_FAILURE;
366 _Unwind_VRS_Pop(context, _UVRSC_WMMXD,
367 RegisterRange(start, count_minus_one),
368 _UVRSD_DOUBLE);
369 break;
370 }
371 case 0xc7: {
372 uint8_t v = getByte(data, offset++);
373 if (!v || v & 0xf0)
374 return _URC_FAILURE;
375 _Unwind_VRS_Pop(context, _UVRSC_WMMXC, v, _UVRSD_DOUBLE);
376 break;
377 }
378#endif
379 case 0xc8:
380 case 0xc9: {
381 uint8_t v = getByte(data, offset++);
382 uint8_t start =
383 static_cast<uint8_t>(((byte == 0xc8) ? 16 : 0) + (v >> 4));
384 uint8_t count_minus_one = v & 0xf;
385 if (start + count_minus_one >= 32)
386 return _URC_FAILURE;
387 _Unwind_VRS_Pop(context, _UVRSC_VFP,
388 RegisterRange(start, count_minus_one),
389 _UVRSD_DOUBLE);
390 break;
391 }
392 default:
393 return _URC_FAILURE;
394 }
395 break;
396 }
397 case 0xd0: {
398 if (byte & 0x08)
399 return _URC_FAILURE;
400 _Unwind_VRS_Pop(context, _UVRSC_VFP, RegisterRange(8, byte & 0x7),
401 _UVRSD_DOUBLE);
402 break;
403 }
404 default:
405 return _URC_FAILURE;
406 }
407 }
408 }
409 if (!wrotePC) {
410 uint32_t lr;
411 _Unwind_VRS_Get(context, _UVRSC_CORE, UNW_ARM_LR, _UVRSD_UINT32, &lr);
412 _Unwind_VRS_Set(context, _UVRSC_CORE, UNW_ARM_IP, _UVRSD_UINT32, &lr);
413 }
414 return _URC_CONTINUE_UNWIND;
415}
416
417extern "C" _LIBUNWIND_EXPORT _Unwind_Reason_Code
418__aeabi_unwind_cpp_pr0(_Unwind_State state, _Unwind_Control_Block *ucbp,
419 _Unwind_Context *context) {
420 return unwindOneFrame(state, ucbp, context);
421}
422
423extern "C" _LIBUNWIND_EXPORT _Unwind_Reason_Code
424__aeabi_unwind_cpp_pr1(_Unwind_State state, _Unwind_Control_Block *ucbp,
425 _Unwind_Context *context) {
426 return unwindOneFrame(state, ucbp, context);
427}
428
429extern "C" _LIBUNWIND_EXPORT _Unwind_Reason_Code
430__aeabi_unwind_cpp_pr2(_Unwind_State state, _Unwind_Control_Block *ucbp,
431 _Unwind_Context *context) {
432 return unwindOneFrame(state, ucbp, context);
433}
434
435static _Unwind_Reason_Code
436unwind_phase1(unw_context_t *uc, unw_cursor_t *cursor, _Unwind_Exception *exception_object) {
437 // EHABI #7.3 discusses preserving the VRS in a "temporary VRS" during
438 // phase 1 and then restoring it to the "primary VRS" for phase 2. The
439 // effect is phase 2 doesn't see any of the VRS manipulations from phase 1.
440 // In this implementation, the phases don't share the VRS backing store.
441 // Instead, they are passed the original |uc| and they create a new VRS
442 // from scratch thus achieving the same effect.
443 __unw_init_local(cursor, uc);
444
445 // Walk each frame looking for a place to stop.
446 for (bool handlerNotFound = true; handlerNotFound;) {
447
448 // See if frame has code to run (has personality routine).
449 unw_proc_info_t frameInfo;
450 if (__unw_get_proc_info(cursor, &frameInfo) != UNW_ESUCCESS) {
451 _LIBUNWIND_TRACE_UNWINDING(
452 "unwind_phase1(ex_ojb=%p): __unw_get_proc_info "
453 "failed => _URC_FATAL_PHASE1_ERROR",
454 static_cast<void *>(exception_object));
455 return _URC_FATAL_PHASE1_ERROR;
456 }
457
458 // When tracing, print state information.
459 if (_LIBUNWIND_TRACING_UNWINDING) {
460 char functionBuf[512];
461 const char *functionName = functionBuf;
462 unw_word_t offset;
463 if ((__unw_get_proc_name(cursor, functionBuf, sizeof(functionBuf),
464 &offset) != UNW_ESUCCESS) ||
465 (frameInfo.start_ip + offset > frameInfo.end_ip))
466 functionName = ".anonymous.";
467 unw_word_t pc;
468 __unw_get_reg(cursor, UNW_REG_IP, &pc);
469 _LIBUNWIND_TRACE_UNWINDING(
470 "unwind_phase1(ex_ojb=%p): pc=0x%" PRIxPTR ", start_ip=0x%" PRIxPTR ", func=%s, "
471 "lsda=0x%" PRIxPTR ", personality=0x%" PRIxPTR,
472 static_cast<void *>(exception_object), pc,
473 frameInfo.start_ip, functionName,
474 frameInfo.lsda, frameInfo.handler);
475 }
476
477 // If there is a personality routine, ask it if it will want to stop at
478 // this frame.
479 if (frameInfo.handler != 0) {
480 __personality_routine p =
481 (__personality_routine)(long)(frameInfo.handler);
482 _LIBUNWIND_TRACE_UNWINDING(
483 "unwind_phase1(ex_ojb=%p): calling personality function %p",
484 static_cast<void *>(exception_object),
485 reinterpret_cast<void *>(reinterpret_cast<uintptr_t>(p)));
486 struct _Unwind_Context *context = (struct _Unwind_Context *)(cursor);
487 exception_object->pr_cache.fnstart = frameInfo.start_ip;
488 exception_object->pr_cache.ehtp =
489 (_Unwind_EHT_Header *)frameInfo.unwind_info;
490 exception_object->pr_cache.additional = frameInfo.flags;
491 _Unwind_Reason_Code personalityResult =
492 (*p)(_US_VIRTUAL_UNWIND_FRAME, exception_object, context);
493 _LIBUNWIND_TRACE_UNWINDING(
494 "unwind_phase1(ex_ojb=%p): personality result %d start_ip %x ehtp %p "
495 "additional %x",
496 static_cast<void *>(exception_object), personalityResult,
497 exception_object->pr_cache.fnstart,
498 static_cast<void *>(exception_object->pr_cache.ehtp),
499 exception_object->pr_cache.additional);
500 switch (personalityResult) {
501 case _URC_HANDLER_FOUND:
502 // found a catch clause or locals that need destructing in this frame
503 // stop search and remember stack pointer at the frame
504 handlerNotFound = false;
505 // p should have initialized barrier_cache. EHABI #7.3.5
506 _LIBUNWIND_TRACE_UNWINDING(
507 "unwind_phase1(ex_ojb=%p): _URC_HANDLER_FOUND",
508 static_cast<void *>(exception_object));
509 return _URC_NO_REASON;
510
511 case _URC_CONTINUE_UNWIND:
512 _LIBUNWIND_TRACE_UNWINDING(
513 "unwind_phase1(ex_ojb=%p): _URC_CONTINUE_UNWIND",
514 static_cast<void *>(exception_object));
515 // continue unwinding
516 break;
517
518 // EHABI #7.3.3
519 case _URC_FAILURE:
520 return _URC_FAILURE;
521
522 default:
523 // something went wrong
524 _LIBUNWIND_TRACE_UNWINDING(
525 "unwind_phase1(ex_ojb=%p): _URC_FATAL_PHASE1_ERROR",
526 static_cast<void *>(exception_object));
527 return _URC_FATAL_PHASE1_ERROR;
528 }
529 }
530 }
531 return _URC_NO_REASON;
532}
533
534static _Unwind_Reason_Code unwind_phase2(unw_context_t *uc, unw_cursor_t *cursor,
535 _Unwind_Exception *exception_object,
536 bool resume) {
537 // See comment at the start of unwind_phase1 regarding VRS integrity.
538 __unw_init_local(cursor, uc);
539
540 _LIBUNWIND_TRACE_UNWINDING("unwind_phase2(ex_ojb=%p)",
541 static_cast<void *>(exception_object));
542 int frame_count = 0;
543
544 // Walk each frame until we reach where search phase said to stop.
545 while (true) {
546 // Ask libunwind to get next frame (skip over first which is
547 // _Unwind_RaiseException or _Unwind_Resume).
548 //
549 // Resume only ever makes sense for 1 frame.
550 _Unwind_State state =
551 resume ? _US_UNWIND_FRAME_RESUME : _US_UNWIND_FRAME_STARTING;
552 if (resume && frame_count == 1) {
553 // On a resume, first unwind the _Unwind_Resume() frame. The next frame
554 // is now the landing pad for the cleanup from a previous execution of
555 // phase2. To continue unwindingly correctly, replace VRS[15] with the
556 // IP of the frame that the previous run of phase2 installed the context
557 // for. After this, continue unwinding as if normal.
558 //
559 // See #7.4.6 for details.
560 __unw_set_reg(cursor, UNW_REG_IP,
561 exception_object->unwinder_cache.reserved2);
562 resume = false;
563 }
564
565 // Get info about this frame.
566 unw_word_t sp;
567 unw_proc_info_t frameInfo;
568 __unw_get_reg(cursor, UNW_REG_SP, &sp);
569 if (__unw_get_proc_info(cursor, &frameInfo) != UNW_ESUCCESS) {
570 _LIBUNWIND_TRACE_UNWINDING(
571 "unwind_phase2(ex_ojb=%p): __unw_get_proc_info "
572 "failed => _URC_FATAL_PHASE2_ERROR",
573 static_cast<void *>(exception_object));
574 return _URC_FATAL_PHASE2_ERROR;
575 }
576
577 // When tracing, print state information.
578 if (_LIBUNWIND_TRACING_UNWINDING) {
579 char functionBuf[512];
580 const char *functionName = functionBuf;
581 unw_word_t offset;
582 if ((__unw_get_proc_name(cursor, functionBuf, sizeof(functionBuf),
583 &offset) != UNW_ESUCCESS) ||
584 (frameInfo.start_ip + offset > frameInfo.end_ip))
585 functionName = ".anonymous.";
586 _LIBUNWIND_TRACE_UNWINDING(
587 "unwind_phase2(ex_ojb=%p): start_ip=0x%" PRIxPTR ", func=%s, sp=0x%" PRIxPTR ", "
588 "lsda=0x%" PRIxPTR ", personality=0x%" PRIxPTR "",
589 static_cast<void *>(exception_object), frameInfo.start_ip,
590 functionName, sp, frameInfo.lsda,
591 frameInfo.handler);
592 }
593
594 // If there is a personality routine, tell it we are unwinding.
595 if (frameInfo.handler != 0) {
596 __personality_routine p =
597 (__personality_routine)(long)(frameInfo.handler);
598 struct _Unwind_Context *context = (struct _Unwind_Context *)(cursor);
599 // EHABI #7.2
600 exception_object->pr_cache.fnstart = frameInfo.start_ip;
601 exception_object->pr_cache.ehtp =
602 (_Unwind_EHT_Header *)frameInfo.unwind_info;
603 exception_object->pr_cache.additional = frameInfo.flags;
604 _Unwind_Reason_Code personalityResult =
605 (*p)(state, exception_object, context);
606 switch (personalityResult) {
607 case _URC_CONTINUE_UNWIND:
608 // Continue unwinding
609 _LIBUNWIND_TRACE_UNWINDING(
610 "unwind_phase2(ex_ojb=%p): _URC_CONTINUE_UNWIND",
611 static_cast<void *>(exception_object));
612 // EHABI #7.2
613 if (sp == exception_object->barrier_cache.sp) {
614 // Phase 1 said we would stop at this frame, but we did not...
615 _LIBUNWIND_ABORT("during phase1 personality function said it would "
616 "stop here, but now in phase2 it did not stop here");
617 }
618 break;
619 case _URC_INSTALL_CONTEXT:
620 _LIBUNWIND_TRACE_UNWINDING(
621 "unwind_phase2(ex_ojb=%p): _URC_INSTALL_CONTEXT",
622 static_cast<void *>(exception_object));
623 // Personality routine says to transfer control to landing pad.
624 // We may get control back if landing pad calls _Unwind_Resume().
625 if (_LIBUNWIND_TRACING_UNWINDING) {
626 unw_word_t pc;
627 __unw_get_reg(cursor, UNW_REG_IP, &pc);
628 __unw_get_reg(cursor, UNW_REG_SP, &sp);
629 _LIBUNWIND_TRACE_UNWINDING("unwind_phase2(ex_ojb=%p): re-entering "
630 "user code with ip=0x%" PRIxPTR ", sp=0x%" PRIxPTR,
631 static_cast<void *>(exception_object),
632 pc, sp);
633 }
634
635 {
636 // EHABI #7.4.1 says we need to preserve pc for when _Unwind_Resume
637 // is called back, to find this same frame.
638 unw_word_t pc;
639 __unw_get_reg(cursor, UNW_REG_IP, &pc);
640 exception_object->unwinder_cache.reserved2 = (uint32_t)pc;
641 }
642 __unw_resume(cursor);
643 // __unw_resume() only returns if there was an error.
644 return _URC_FATAL_PHASE2_ERROR;
645
646 // # EHABI #7.4.3
647 case _URC_FAILURE:
648 abort();
649
650 default:
651 // Personality routine returned an unknown result code.
652 _LIBUNWIND_DEBUG_LOG("personality function returned unknown result %d",
653 personalityResult);
654 return _URC_FATAL_PHASE2_ERROR;
655 }
656 }
657 frame_count++;
658 }
659
660 // Clean up phase did not resume at the frame that the search phase
661 // said it would...
662 return _URC_FATAL_PHASE2_ERROR;
663}
664
665/// Called by __cxa_throw. Only returns if there is a fatal error.
666_LIBUNWIND_EXPORT _Unwind_Reason_Code
667_Unwind_RaiseException(_Unwind_Exception *exception_object) {
668 _LIBUNWIND_TRACE_API("_Unwind_RaiseException(ex_obj=%p)",
669 static_cast<void *>(exception_object));
670 unw_context_t uc;
671 unw_cursor_t cursor;
672 __unw_getcontext(&uc);
673
674 // This field for is for compatibility with GCC to say this isn't a forced
675 // unwind. EHABI #7.2
676 exception_object->unwinder_cache.reserved1 = 0;
677
678 // phase 1: the search phase
679 _Unwind_Reason_Code phase1 = unwind_phase1(&uc, &cursor, exception_object);
680 if (phase1 != _URC_NO_REASON)
681 return phase1;
682
683 // phase 2: the clean up phase
684 return unwind_phase2(&uc, &cursor, exception_object, false);
685}
686
687_LIBUNWIND_EXPORT void _Unwind_Complete(_Unwind_Exception* exception_object) {
688 // This is to be called when exception handling completes to give us a chance
689 // to perform any housekeeping. EHABI #7.2. But we have nothing to do here.
690 (void)exception_object;
691}
692
693/// When _Unwind_RaiseException() is in phase2, it hands control
694/// to the personality function at each frame. The personality
695/// may force a jump to a landing pad in that function, the landing
696/// pad code may then call _Unwind_Resume() to continue with the
697/// unwinding. Note: the call to _Unwind_Resume() is from compiler
698/// geneated user code. All other _Unwind_* routines are called
699/// by the C++ runtime __cxa_* routines.
700///
701/// Note: re-throwing an exception (as opposed to continuing the unwind)
702/// is implemented by having the code call __cxa_rethrow() which
703/// in turn calls _Unwind_Resume_or_Rethrow().
704_LIBUNWIND_EXPORT void
705_Unwind_Resume(_Unwind_Exception *exception_object) {
706 _LIBUNWIND_TRACE_API("_Unwind_Resume(ex_obj=%p)",
707 static_cast<void *>(exception_object));
708 unw_context_t uc;
709 unw_cursor_t cursor;
710 __unw_getcontext(&uc);
711
712 // _Unwind_RaiseException on EHABI will always set the reserved1 field to 0,
713 // which is in the same position as private_1 below.
714 // TODO(ajwong): Who wronte the above? Why is it true?
715 unwind_phase2(&uc, &cursor, exception_object, true);
716
717 // Clients assume _Unwind_Resume() does not return, so all we can do is abort.
718 _LIBUNWIND_ABORT("_Unwind_Resume() can't return");
719}
720
721/// Called by personality handler during phase 2 to get LSDA for current frame.
722_LIBUNWIND_EXPORT uintptr_t
723_Unwind_GetLanguageSpecificData(struct _Unwind_Context *context) {
724 unw_cursor_t *cursor = (unw_cursor_t *)context;
725 unw_proc_info_t frameInfo;
726 uintptr_t result = 0;
727 if (__unw_get_proc_info(cursor, &frameInfo) == UNW_ESUCCESS)
728 result = (uintptr_t)frameInfo.lsda;
729 _LIBUNWIND_TRACE_API(
730 "_Unwind_GetLanguageSpecificData(context=%p) => 0x%llx",
731 static_cast<void *>(context), (long long)result);
732 return result;
733}
734
735static uint64_t ValueAsBitPattern(_Unwind_VRS_DataRepresentation representation,
736 void* valuep) {
737 uint64_t value = 0;
738 switch (representation) {
739 case _UVRSD_UINT32:
740 case _UVRSD_FLOAT:
741 memcpy(&value, valuep, sizeof(uint32_t));
742 break;
743
744 case _UVRSD_VFPX:
745 case _UVRSD_UINT64:
746 case _UVRSD_DOUBLE:
747 memcpy(&value, valuep, sizeof(uint64_t));
748 break;
749 }
750 return value;
751}
752
753_LIBUNWIND_EXPORT _Unwind_VRS_Result
754_Unwind_VRS_Set(_Unwind_Context *context, _Unwind_VRS_RegClass regclass,
755 uint32_t regno, _Unwind_VRS_DataRepresentation representation,
756 void *valuep) {
757 _LIBUNWIND_TRACE_API("_Unwind_VRS_Set(context=%p, regclass=%d, reg=%d, "
758 "rep=%d, value=0x%llX)",
759 static_cast<void *>(context), regclass, regno,
760 representation,
761 ValueAsBitPattern(representation, valuep));
762 unw_cursor_t *cursor = (unw_cursor_t *)context;
763 switch (regclass) {
764 case _UVRSC_CORE:
765 if (representation != _UVRSD_UINT32 || regno > 15)
766 return _UVRSR_FAILED;
767 return __unw_set_reg(cursor, (unw_regnum_t)(UNW_ARM_R0 + regno),
768 *(unw_word_t *)valuep) == UNW_ESUCCESS
769 ? _UVRSR_OK
770 : _UVRSR_FAILED;
771 case _UVRSC_VFP:
772 if (representation != _UVRSD_VFPX && representation != _UVRSD_DOUBLE)
773 return _UVRSR_FAILED;
774 if (representation == _UVRSD_VFPX) {
775 // Can only touch d0-15 with FSTMFDX.
776 if (regno > 15)
777 return _UVRSR_FAILED;
778 __unw_save_vfp_as_X(cursor);
779 } else {
780 if (regno > 31)
781 return _UVRSR_FAILED;
782 }
783 return __unw_set_fpreg(cursor, (unw_regnum_t)(UNW_ARM_D0 + regno),
784 *(unw_fpreg_t *)valuep) == UNW_ESUCCESS
785 ? _UVRSR_OK
786 : _UVRSR_FAILED;
787#if defined(__ARM_WMMX)
788 case _UVRSC_WMMXC:
789 if (representation != _UVRSD_UINT32 || regno > 3)
790 return _UVRSR_FAILED;
791 return __unw_set_reg(cursor, (unw_regnum_t)(UNW_ARM_WC0 + regno),
792 *(unw_word_t *)valuep) == UNW_ESUCCESS
793 ? _UVRSR_OK
794 : _UVRSR_FAILED;
795 case _UVRSC_WMMXD:
796 if (representation != _UVRSD_DOUBLE || regno > 31)
797 return _UVRSR_FAILED;
798 return __unw_set_fpreg(cursor, (unw_regnum_t)(UNW_ARM_WR0 + regno),
799 *(unw_fpreg_t *)valuep) == UNW_ESUCCESS
800 ? _UVRSR_OK
801 : _UVRSR_FAILED;
802#else
803 case _UVRSC_WMMXC:
804 case _UVRSC_WMMXD:
805 break;
806#endif
807 }
808 _LIBUNWIND_ABORT("unsupported register class");
809}
810
811static _Unwind_VRS_Result
812_Unwind_VRS_Get_Internal(_Unwind_Context *context,
813 _Unwind_VRS_RegClass regclass, uint32_t regno,
814 _Unwind_VRS_DataRepresentation representation,
815 void *valuep) {
816 unw_cursor_t *cursor = (unw_cursor_t *)context;
817 switch (regclass) {
818 case _UVRSC_CORE:
819 if (representation != _UVRSD_UINT32 || regno > 15)
820 return _UVRSR_FAILED;
821 return __unw_get_reg(cursor, (unw_regnum_t)(UNW_ARM_R0 + regno),
822 (unw_word_t *)valuep) == UNW_ESUCCESS
823 ? _UVRSR_OK
824 : _UVRSR_FAILED;
825 case _UVRSC_VFP:
826 if (representation != _UVRSD_VFPX && representation != _UVRSD_DOUBLE)
827 return _UVRSR_FAILED;
828 if (representation == _UVRSD_VFPX) {
829 // Can only touch d0-15 with FSTMFDX.
830 if (regno > 15)
831 return _UVRSR_FAILED;
832 __unw_save_vfp_as_X(cursor);
833 } else {
834 if (regno > 31)
835 return _UVRSR_FAILED;
836 }
837 return __unw_get_fpreg(cursor, (unw_regnum_t)(UNW_ARM_D0 + regno),
838 (unw_fpreg_t *)valuep) == UNW_ESUCCESS
839 ? _UVRSR_OK
840 : _UVRSR_FAILED;
841#if defined(__ARM_WMMX)
842 case _UVRSC_WMMXC:
843 if (representation != _UVRSD_UINT32 || regno > 3)
844 return _UVRSR_FAILED;
845 return __unw_get_reg(cursor, (unw_regnum_t)(UNW_ARM_WC0 + regno),
846 (unw_word_t *)valuep) == UNW_ESUCCESS
847 ? _UVRSR_OK
848 : _UVRSR_FAILED;
849 case _UVRSC_WMMXD:
850 if (representation != _UVRSD_DOUBLE || regno > 31)
851 return _UVRSR_FAILED;
852 return __unw_get_fpreg(cursor, (unw_regnum_t)(UNW_ARM_WR0 + regno),
853 (unw_fpreg_t *)valuep) == UNW_ESUCCESS
854 ? _UVRSR_OK
855 : _UVRSR_FAILED;
856#else
857 case _UVRSC_WMMXC:
858 case _UVRSC_WMMXD:
859 break;
860#endif
861 }
862 _LIBUNWIND_ABORT("unsupported register class");
863}
864
865_LIBUNWIND_EXPORT _Unwind_VRS_Result
866_Unwind_VRS_Get(_Unwind_Context *context, _Unwind_VRS_RegClass regclass,
867 uint32_t regno, _Unwind_VRS_DataRepresentation representation,
868 void *valuep) {
869 _Unwind_VRS_Result result =
870 _Unwind_VRS_Get_Internal(context, regclass, regno, representation,
871 valuep);
872 _LIBUNWIND_TRACE_API("_Unwind_VRS_Get(context=%p, regclass=%d, reg=%d, "
873 "rep=%d, value=0x%llX, result = %d)",
874 static_cast<void *>(context), regclass, regno,
875 representation,
876 ValueAsBitPattern(representation, valuep), result);
877 return result;
878}
879
880_Unwind_VRS_Result
881_Unwind_VRS_Pop(_Unwind_Context *context, _Unwind_VRS_RegClass regclass,
882 uint32_t discriminator,
883 _Unwind_VRS_DataRepresentation representation) {
884 _LIBUNWIND_TRACE_API("_Unwind_VRS_Pop(context=%p, regclass=%d, "
885 "discriminator=%d, representation=%d)",
886 static_cast<void *>(context), regclass, discriminator,
887 representation);
888 switch (regclass) {
889 case _UVRSC_WMMXC:
890#if !defined(__ARM_WMMX)
891 break;
892#endif
893 case _UVRSC_CORE: {
894 if (representation != _UVRSD_UINT32)
895 return _UVRSR_FAILED;
896 // When popping SP from the stack, we don't want to override it from the
897 // computed new stack location. See EHABI #7.5.4 table 3.
898 bool poppedSP = false;
899 uint32_t* sp;
900 if (_Unwind_VRS_Get(context, _UVRSC_CORE, UNW_ARM_SP,
901 _UVRSD_UINT32, &sp) != _UVRSR_OK) {
902 return _UVRSR_FAILED;
903 }
904 for (uint32_t i = 0; i < 16; ++i) {
905 if (!(discriminator & static_cast<uint32_t>(1 << i)))
906 continue;
907 uint32_t value = *sp++;
908 if (regclass == _UVRSC_CORE && i == 13)
909 poppedSP = true;
910 if (_Unwind_VRS_Set(context, regclass, i,
911 _UVRSD_UINT32, &value) != _UVRSR_OK) {
912 return _UVRSR_FAILED;
913 }
914 }
915 if (!poppedSP) {
916 return _Unwind_VRS_Set(context, _UVRSC_CORE, UNW_ARM_SP,
917 _UVRSD_UINT32, &sp);
918 }
919 return _UVRSR_OK;
920 }
921 case _UVRSC_WMMXD:
922#if !defined(__ARM_WMMX)
923 break;
924#endif
925 case _UVRSC_VFP: {
926 if (representation != _UVRSD_VFPX && representation != _UVRSD_DOUBLE)
927 return _UVRSR_FAILED;
928 uint32_t first = discriminator >> 16;
929 uint32_t count = discriminator & 0xffff;
930 uint32_t end = first+count;
931 uint32_t* sp;
932 if (_Unwind_VRS_Get(context, _UVRSC_CORE, UNW_ARM_SP,
933 _UVRSD_UINT32, &sp) != _UVRSR_OK) {
934 return _UVRSR_FAILED;
935 }
936 // For _UVRSD_VFPX, we're assuming the data is stored in FSTMX "standard
937 // format 1", which is equivalent to FSTMD + a padding word.
938 for (uint32_t i = first; i < end; ++i) {
939 // SP is only 32-bit aligned so don't copy 64-bit at a time.
940 uint64_t value = *sp++;
941 value |= ((uint64_t)(*sp++)) << 32;
942 if (_Unwind_VRS_Set(context, regclass, i, representation, &value) !=
943 _UVRSR_OK)
944 return _UVRSR_FAILED;
945 }
946 if (representation == _UVRSD_VFPX)
947 ++sp;
948 return _Unwind_VRS_Set(context, _UVRSC_CORE, UNW_ARM_SP, _UVRSD_UINT32,
949 &sp);
950 }
951 }
952 _LIBUNWIND_ABORT("unsupported register class");
953}
954
955/// Called by personality handler during phase 2 to find the start of the
956/// function.
957_LIBUNWIND_EXPORT uintptr_t
958_Unwind_GetRegionStart(struct _Unwind_Context *context) {
959 unw_cursor_t *cursor = (unw_cursor_t *)context;
960 unw_proc_info_t frameInfo;
961 uintptr_t result = 0;
962 if (__unw_get_proc_info(cursor, &frameInfo) == UNW_ESUCCESS)
963 result = (uintptr_t)frameInfo.start_ip;
964 _LIBUNWIND_TRACE_API("_Unwind_GetRegionStart(context=%p) => 0x%llX",
965 static_cast<void *>(context), (long long)result);
966 return result;
967}
968
969
970/// Called by personality handler during phase 2 if a foreign exception
971// is caught.
972_LIBUNWIND_EXPORT void
973_Unwind_DeleteException(_Unwind_Exception *exception_object) {
974 _LIBUNWIND_TRACE_API("_Unwind_DeleteException(ex_obj=%p)",
975 static_cast<void *>(exception_object));
976 if (exception_object->exception_cleanup != NULL)
977 (*exception_object->exception_cleanup)(_URC_FOREIGN_EXCEPTION_CAUGHT,
978 exception_object);
979}
980
981extern "C" _LIBUNWIND_EXPORT _Unwind_Reason_Code
982__gnu_unwind_frame(_Unwind_Exception *exception_object,
983 struct _Unwind_Context *context) {
984 unw_cursor_t *cursor = (unw_cursor_t *)context;
985 if (__unw_step(cursor) != UNW_STEP_SUCCESS)
986 return _URC_FAILURE;
987 return _URC_OK;
988}
989
990#endif // defined(_LIBUNWIND_ARM_EHABI)
991