1 //===--------------------------- Unwind-EHABI.cpp -------------------------===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is dual licensed under the MIT and the University of Illinois Open 6 // Source Licenses. See LICENSE.TXT for details. 7 // 8 // 9 // Implements ARM zero-cost C++ exceptions 10 // 11 //===----------------------------------------------------------------------===// 12 13 #include "Unwind-EHABI.h" 14 15 #if _LIBUNWIND_ARM_EHABI 16 17 #include <stdbool.h> 18 #include <stdint.h> 19 #include <stdio.h> 20 #include <stdlib.h> 21 #include <string.h> 22 23 #include <type_traits> 24 25 #include "config.h" 26 #include "libunwind.h" 27 #include "libunwind_ext.h" 28 #include "unwind.h" 29 30 namespace { 31 32 // Strange order: take words in order, but inside word, take from most to least 33 // signinficant byte. 34 uint8_t getByte(const uint32_t* data, size_t offset) { 35 const uint8_t* byteData = reinterpret_cast<const uint8_t*>(data); 36 return byteData[(offset & ~(size_t)0x03) + (3 - (offset & (size_t)0x03))]; 37 } 38 39 const char* getNextWord(const char* data, uint32_t* out) { 40 *out = *reinterpret_cast<const uint32_t*>(data); 41 return data + 4; 42 } 43 44 const char* getNextNibble(const char* data, uint32_t* out) { 45 *out = *reinterpret_cast<const uint16_t*>(data); 46 return data + 2; 47 } 48 49 struct Descriptor { 50 // See # 9.2 51 typedef enum { 52 SU16 = 0, // Short descriptor, 16-bit entries 53 LU16 = 1, // Long descriptor, 16-bit entries 54 LU32 = 3, // Long descriptor, 32-bit entries 55 RESERVED0 = 4, RESERVED1 = 5, RESERVED2 = 6, RESERVED3 = 7, 56 RESERVED4 = 8, RESERVED5 = 9, RESERVED6 = 10, RESERVED7 = 11, 57 RESERVED8 = 12, RESERVED9 = 13, RESERVED10 = 14, RESERVED11 = 15 58 } Format; 59 60 // See # 9.2 61 typedef enum { 62 CLEANUP = 0x0, 63 FUNC = 0x1, 64 CATCH = 0x2, 65 INVALID = 0x4 66 } Kind; 67 }; 68 69 _Unwind_Reason_Code ProcessDescriptors( 70 _Unwind_State state, 71 _Unwind_Control_Block* ucbp, 72 struct _Unwind_Context* context, 73 Descriptor::Format format, 74 const char* descriptorStart, 75 uint32_t flags) { 76 77 // EHT is inlined in the index using compact form. No descriptors. #5 78 if (flags & 0x1) 79 return _URC_CONTINUE_UNWIND; 80 81 // TODO: We should check the state here, and determine whether we need to 82 // perform phase1 or phase2 unwinding. 83 (void)state; 84 85 const char* descriptor = descriptorStart; 86 uint32_t descriptorWord; 87 getNextWord(descriptor, &descriptorWord); 88 while (descriptorWord) { 89 // Read descriptor based on # 9.2. 90 uint32_t length; 91 uint32_t offset; 92 switch (format) { 93 case Descriptor::LU32: 94 descriptor = getNextWord(descriptor, &length); 95 descriptor = getNextWord(descriptor, &offset); 96 case Descriptor::LU16: 97 descriptor = getNextNibble(descriptor, &length); 98 descriptor = getNextNibble(descriptor, &offset); 99 default: 100 assert(false); 101 return _URC_FAILURE; 102 } 103 104 // See # 9.2 table for decoding the kind of descriptor. It's a 2-bit value. 105 Descriptor::Kind kind = 106 static_cast<Descriptor::Kind>((length & 0x1) | ((offset & 0x1) << 1)); 107 108 // Clear off flag from last bit. 109 length &= ~1u; 110 offset &= ~1u; 111 uintptr_t scopeStart = ucbp->pr_cache.fnstart + offset; 112 uintptr_t scopeEnd = scopeStart + length; 113 uintptr_t pc = _Unwind_GetIP(context); 114 bool isInScope = (scopeStart <= pc) && (pc < scopeEnd); 115 116 switch (kind) { 117 case Descriptor::CLEANUP: { 118 // TODO(ajwong): Handle cleanup descriptors. 119 break; 120 } 121 case Descriptor::FUNC: { 122 // TODO(ajwong): Handle function descriptors. 123 break; 124 } 125 case Descriptor::CATCH: { 126 // Catch descriptors require gobbling one more word. 127 uint32_t landing_pad; 128 descriptor = getNextWord(descriptor, &landing_pad); 129 130 if (isInScope) { 131 // TODO(ajwong): This is only phase1 compatible logic. Implement 132 // phase2. 133 landing_pad = signExtendPrel31(landing_pad & ~0x80000000); 134 if (landing_pad == 0xffffffff) { 135 return _URC_HANDLER_FOUND; 136 } else if (landing_pad == 0xfffffffe) { 137 return _URC_FAILURE; 138 } else { 139 /* 140 bool is_reference_type = landing_pad & 0x80000000; 141 void* matched_object; 142 if (__cxxabiv1::__cxa_type_match( 143 ucbp, reinterpret_cast<const std::type_info *>(landing_pad), 144 is_reference_type, 145 &matched_object) != __cxxabiv1::ctm_failed) 146 return _URC_HANDLER_FOUND; 147 */ 148 _LIBUNWIND_ABORT("Type matching not implemented"); 149 } 150 } 151 break; 152 } 153 default: 154 _LIBUNWIND_ABORT("Invalid descriptor kind found."); 155 } 156 157 getNextWord(descriptor, &descriptorWord); 158 } 159 160 return _URC_CONTINUE_UNWIND; 161 } 162 163 static _Unwind_Reason_Code unwindOneFrame(_Unwind_State state, 164 _Unwind_Control_Block* ucbp, 165 struct _Unwind_Context* context) { 166 // Read the compact model EHT entry's header # 6.3 167 const uint32_t* unwindingData = ucbp->pr_cache.ehtp; 168 assert((*unwindingData & 0xf0000000) == 0x80000000 && "Must be a compact entry"); 169 Descriptor::Format format = 170 static_cast<Descriptor::Format>((*unwindingData & 0x0f000000) >> 24); 171 172 const char *lsda = 173 reinterpret_cast<const char *>(_Unwind_GetLanguageSpecificData(context)); 174 175 // Handle descriptors before unwinding so they are processed in the context 176 // of the correct stack frame. 177 _Unwind_Reason_Code result = 178 ProcessDescriptors(state, ucbp, context, format, lsda, 179 ucbp->pr_cache.additional); 180 181 if (result != _URC_CONTINUE_UNWIND) 182 return result; 183 184 if (unw_step(reinterpret_cast<unw_cursor_t*>(context)) != UNW_STEP_SUCCESS) 185 return _URC_FAILURE; 186 return _URC_CONTINUE_UNWIND; 187 } 188 189 // Generates mask discriminator for _Unwind_VRS_Pop, e.g. for _UVRSC_CORE / 190 // _UVRSD_UINT32. 191 uint32_t RegisterMask(uint8_t start, uint8_t count_minus_one) { 192 return ((1U << (count_minus_one + 1)) - 1) << start; 193 } 194 195 // Generates mask discriminator for _Unwind_VRS_Pop, e.g. for _UVRSC_VFP / 196 // _UVRSD_DOUBLE. 197 uint32_t RegisterRange(uint8_t start, uint8_t count_minus_one) { 198 return ((uint32_t)start << 16) | ((uint32_t)count_minus_one + 1); 199 } 200 201 } // end anonymous namespace 202 203 /** 204 * Decodes an EHT entry. 205 * 206 * @param data Pointer to EHT. 207 * @param[out] off Offset from return value (in bytes) to begin interpretation. 208 * @param[out] len Number of bytes in unwind code. 209 * @return Pointer to beginning of unwind code. 210 */ 211 extern "C" const uint32_t* 212 decode_eht_entry(const uint32_t* data, size_t* off, size_t* len) { 213 if ((*data & 0x80000000) == 0) { 214 // 6.2: Generic Model 215 // 216 // EHT entry is a prel31 pointing to the PR, followed by data understood 217 // only by the personality routine. Fortunately, all existing assembler 218 // implementations, including GNU assembler, LLVM integrated assembler, 219 // and ARM assembler, assume that the unwind opcodes come after the 220 // personality rountine address. 221 *off = 1; // First byte is size data. 222 *len = (((data[1] >> 24) & 0xff) + 1) * 4; 223 data++; // Skip the first word, which is the prel31 offset. 224 } else { 225 // 6.3: ARM Compact Model 226 // 227 // EHT entries here correspond to the __aeabi_unwind_cpp_pr[012] PRs indeded 228 // by format: 229 Descriptor::Format format = 230 static_cast<Descriptor::Format>((*data & 0x0f000000) >> 24); 231 switch (format) { 232 case Descriptor::SU16: 233 *len = 4; 234 *off = 1; 235 break; 236 case Descriptor::LU16: 237 case Descriptor::LU32: 238 *len = 4 + 4 * ((*data & 0x00ff0000) >> 16); 239 *off = 2; 240 break; 241 default: 242 return nullptr; 243 } 244 } 245 return data; 246 } 247 248 _Unwind_Reason_Code _Unwind_VRS_Interpret( 249 _Unwind_Context* context, 250 const uint32_t* data, 251 size_t offset, 252 size_t len) { 253 bool wrotePC = false; 254 bool finish = false; 255 while (offset < len && !finish) { 256 uint8_t byte = getByte(data, offset++); 257 if ((byte & 0x80) == 0) { 258 uint32_t sp; 259 _Unwind_VRS_Get(context, _UVRSC_CORE, UNW_ARM_SP, _UVRSD_UINT32, &sp); 260 if (byte & 0x40) 261 sp -= (((uint32_t)byte & 0x3f) << 2) + 4; 262 else 263 sp += ((uint32_t)byte << 2) + 4; 264 _Unwind_VRS_Set(context, _UVRSC_CORE, UNW_ARM_SP, _UVRSD_UINT32, &sp); 265 } else { 266 switch (byte & 0xf0) { 267 case 0x80: { 268 if (offset >= len) 269 return _URC_FAILURE; 270 uint32_t registers = 271 (((uint32_t)byte & 0x0f) << 12) | 272 (((uint32_t)getByte(data, offset++)) << 4); 273 if (!registers) 274 return _URC_FAILURE; 275 if (registers & (1 << 15)) 276 wrotePC = true; 277 _Unwind_VRS_Pop(context, _UVRSC_CORE, registers, _UVRSD_UINT32); 278 break; 279 } 280 case 0x90: { 281 uint8_t reg = byte & 0x0f; 282 if (reg == 13 || reg == 15) 283 return _URC_FAILURE; 284 uint32_t sp; 285 _Unwind_VRS_Get(context, _UVRSC_CORE, UNW_ARM_R0 + reg, 286 _UVRSD_UINT32, &sp); 287 _Unwind_VRS_Set(context, _UVRSC_CORE, UNW_ARM_SP, _UVRSD_UINT32, 288 &sp); 289 break; 290 } 291 case 0xa0: { 292 uint32_t registers = RegisterMask(4, byte & 0x07); 293 if (byte & 0x08) 294 registers |= 1 << 14; 295 _Unwind_VRS_Pop(context, _UVRSC_CORE, registers, _UVRSD_UINT32); 296 break; 297 } 298 case 0xb0: { 299 switch (byte) { 300 case 0xb0: 301 finish = true; 302 break; 303 case 0xb1: { 304 if (offset >= len) 305 return _URC_FAILURE; 306 uint8_t registers = getByte(data, offset++); 307 if (registers & 0xf0 || !registers) 308 return _URC_FAILURE; 309 _Unwind_VRS_Pop(context, _UVRSC_CORE, registers, _UVRSD_UINT32); 310 break; 311 } 312 case 0xb2: { 313 uint32_t addend = 0; 314 uint32_t shift = 0; 315 // This decodes a uleb128 value. 316 while (true) { 317 if (offset >= len) 318 return _URC_FAILURE; 319 uint32_t v = getByte(data, offset++); 320 addend |= (v & 0x7f) << shift; 321 if ((v & 0x80) == 0) 322 break; 323 shift += 7; 324 } 325 uint32_t sp; 326 _Unwind_VRS_Get(context, _UVRSC_CORE, UNW_ARM_SP, _UVRSD_UINT32, 327 &sp); 328 sp += 0x204 + (addend << 2); 329 _Unwind_VRS_Set(context, _UVRSC_CORE, UNW_ARM_SP, _UVRSD_UINT32, 330 &sp); 331 break; 332 } 333 case 0xb3: { 334 uint8_t v = getByte(data, offset++); 335 _Unwind_VRS_Pop(context, _UVRSC_VFP, 336 RegisterRange(static_cast<uint8_t>(v >> 4), 337 v & 0x0f), _UVRSD_VFPX); 338 break; 339 } 340 case 0xb4: 341 case 0xb5: 342 case 0xb6: 343 case 0xb7: 344 return _URC_FAILURE; 345 default: 346 _Unwind_VRS_Pop(context, _UVRSC_VFP, 347 RegisterRange(8, byte & 0x07), _UVRSD_VFPX); 348 break; 349 } 350 break; 351 } 352 case 0xc0: { 353 switch (byte) { 354 #if defined(__ARM_WMMX) 355 case 0xc0: 356 case 0xc1: 357 case 0xc2: 358 case 0xc3: 359 case 0xc4: 360 case 0xc5: 361 _Unwind_VRS_Pop(context, _UVRSC_WMMXD, 362 RegisterRange(10, byte & 0x7), _UVRSD_DOUBLE); 363 break; 364 case 0xc6: { 365 uint8_t v = getByte(data, offset++); 366 uint8_t start = static_cast<uint8_t>(v >> 4); 367 uint8_t count_minus_one = v & 0xf; 368 if (start + count_minus_one >= 16) 369 return _URC_FAILURE; 370 _Unwind_VRS_Pop(context, _UVRSC_WMMXD, 371 RegisterRange(start, count_minus_one), 372 _UVRSD_DOUBLE); 373 break; 374 } 375 case 0xc7: { 376 uint8_t v = getByte(data, offset++); 377 if (!v || v & 0xf0) 378 return _URC_FAILURE; 379 _Unwind_VRS_Pop(context, _UVRSC_WMMXC, v, _UVRSD_DOUBLE); 380 break; 381 } 382 #endif 383 case 0xc8: 384 case 0xc9: { 385 uint8_t v = getByte(data, offset++); 386 uint8_t start = 387 static_cast<uint8_t>(((byte == 0xc8) ? 16 : 0) + (v >> 4)); 388 uint8_t count_minus_one = v & 0xf; 389 if (start + count_minus_one >= 32) 390 return _URC_FAILURE; 391 _Unwind_VRS_Pop(context, _UVRSC_VFP, 392 RegisterRange(start, count_minus_one), 393 _UVRSD_DOUBLE); 394 break; 395 } 396 default: 397 return _URC_FAILURE; 398 } 399 break; 400 } 401 case 0xd0: { 402 if (byte & 0x08) 403 return _URC_FAILURE; 404 _Unwind_VRS_Pop(context, _UVRSC_VFP, RegisterRange(8, byte & 0x7), 405 _UVRSD_DOUBLE); 406 break; 407 } 408 default: 409 return _URC_FAILURE; 410 } 411 } 412 } 413 if (!wrotePC) { 414 uint32_t lr; 415 _Unwind_VRS_Get(context, _UVRSC_CORE, UNW_ARM_LR, _UVRSD_UINT32, &lr); 416 _Unwind_VRS_Set(context, _UVRSC_CORE, UNW_ARM_IP, _UVRSD_UINT32, &lr); 417 } 418 return _URC_CONTINUE_UNWIND; 419 } 420 421 extern "C" _Unwind_Reason_Code __aeabi_unwind_cpp_pr0( 422 _Unwind_State state, 423 _Unwind_Control_Block *ucbp, 424 _Unwind_Context *context) { 425 return unwindOneFrame(state, ucbp, context); 426 } 427 428 extern "C" _Unwind_Reason_Code __aeabi_unwind_cpp_pr1( 429 _Unwind_State state, 430 _Unwind_Control_Block *ucbp, 431 _Unwind_Context *context) { 432 return unwindOneFrame(state, ucbp, context); 433 } 434 435 extern "C" _Unwind_Reason_Code __aeabi_unwind_cpp_pr2( 436 _Unwind_State state, 437 _Unwind_Control_Block *ucbp, 438 _Unwind_Context *context) { 439 return unwindOneFrame(state, ucbp, context); 440 } 441 442 static _Unwind_Reason_Code 443 unwind_phase1(unw_context_t *uc, unw_cursor_t *cursor, _Unwind_Exception *exception_object) { 444 // EHABI #7.3 discusses preserving the VRS in a "temporary VRS" during 445 // phase 1 and then restoring it to the "primary VRS" for phase 2. The 446 // effect is phase 2 doesn't see any of the VRS manipulations from phase 1. 447 // In this implementation, the phases don't share the VRS backing store. 448 // Instead, they are passed the original |uc| and they create a new VRS 449 // from scratch thus achieving the same effect. 450 unw_init_local(cursor, uc); 451 452 // Walk each frame looking for a place to stop. 453 for (bool handlerNotFound = true; handlerNotFound;) { 454 455 // See if frame has code to run (has personality routine). 456 unw_proc_info_t frameInfo; 457 if (unw_get_proc_info(cursor, &frameInfo) != UNW_ESUCCESS) { 458 _LIBUNWIND_TRACE_UNWINDING("unwind_phase1(ex_ojb=%p): unw_get_proc_info " 459 "failed => _URC_FATAL_PHASE1_ERROR", 460 static_cast<void *>(exception_object)); 461 return _URC_FATAL_PHASE1_ERROR; 462 } 463 464 // When tracing, print state information. 465 if (_LIBUNWIND_TRACING_UNWINDING) { 466 char functionBuf[512]; 467 const char *functionName = functionBuf; 468 unw_word_t offset; 469 if ((unw_get_proc_name(cursor, functionBuf, sizeof(functionBuf), 470 &offset) != UNW_ESUCCESS) || 471 (frameInfo.start_ip + offset > frameInfo.end_ip)) 472 functionName = ".anonymous."; 473 unw_word_t pc; 474 unw_get_reg(cursor, UNW_REG_IP, &pc); 475 _LIBUNWIND_TRACE_UNWINDING( 476 "unwind_phase1(ex_ojb=%p): pc=0x%llX, start_ip=0x%llX, func=%s, " 477 "lsda=0x%llX, personality=0x%llX", 478 static_cast<void *>(exception_object), (long long)pc, 479 (long long)frameInfo.start_ip, functionName, 480 (long long)frameInfo.lsda, (long long)frameInfo.handler); 481 } 482 483 // If there is a personality routine, ask it if it will want to stop at 484 // this frame. 485 if (frameInfo.handler != 0) { 486 __personality_routine p = 487 (__personality_routine)(long)(frameInfo.handler); 488 _LIBUNWIND_TRACE_UNWINDING( 489 "unwind_phase1(ex_ojb=%p): calling personality function %p", 490 static_cast<void *>(exception_object), 491 reinterpret_cast<void *>(reinterpret_cast<uintptr_t>(p))); 492 struct _Unwind_Context *context = (struct _Unwind_Context *)(cursor); 493 exception_object->pr_cache.fnstart = frameInfo.start_ip; 494 exception_object->pr_cache.ehtp = 495 (_Unwind_EHT_Header *)frameInfo.unwind_info; 496 exception_object->pr_cache.additional = frameInfo.flags; 497 _Unwind_Reason_Code personalityResult = 498 (*p)(_US_VIRTUAL_UNWIND_FRAME, exception_object, context); 499 _LIBUNWIND_TRACE_UNWINDING( 500 "unwind_phase1(ex_ojb=%p): personality result %d start_ip %x ehtp %p " 501 "additional %x", 502 static_cast<void *>(exception_object), personalityResult, 503 exception_object->pr_cache.fnstart, 504 static_cast<void *>(exception_object->pr_cache.ehtp), 505 exception_object->pr_cache.additional); 506 switch (personalityResult) { 507 case _URC_HANDLER_FOUND: 508 // found a catch clause or locals that need destructing in this frame 509 // stop search and remember stack pointer at the frame 510 handlerNotFound = false; 511 // p should have initialized barrier_cache. EHABI #7.3.5 512 _LIBUNWIND_TRACE_UNWINDING( 513 "unwind_phase1(ex_ojb=%p): _URC_HANDLER_FOUND", 514 static_cast<void *>(exception_object)); 515 return _URC_NO_REASON; 516 517 case _URC_CONTINUE_UNWIND: 518 _LIBUNWIND_TRACE_UNWINDING( 519 "unwind_phase1(ex_ojb=%p): _URC_CONTINUE_UNWIND", 520 static_cast<void *>(exception_object)); 521 // continue unwinding 522 break; 523 524 // EHABI #7.3.3 525 case _URC_FAILURE: 526 return _URC_FAILURE; 527 528 default: 529 // something went wrong 530 _LIBUNWIND_TRACE_UNWINDING( 531 "unwind_phase1(ex_ojb=%p): _URC_FATAL_PHASE1_ERROR", 532 static_cast<void *>(exception_object)); 533 return _URC_FATAL_PHASE1_ERROR; 534 } 535 } 536 } 537 return _URC_NO_REASON; 538 } 539 540 static _Unwind_Reason_Code unwind_phase2(unw_context_t *uc, unw_cursor_t *cursor, 541 _Unwind_Exception *exception_object, 542 bool resume) { 543 // See comment at the start of unwind_phase1 regarding VRS integrity. 544 unw_init_local(cursor, uc); 545 546 _LIBUNWIND_TRACE_UNWINDING("unwind_phase2(ex_ojb=%p)", 547 static_cast<void *>(exception_object)); 548 int frame_count = 0; 549 550 // Walk each frame until we reach where search phase said to stop. 551 while (true) { 552 // Ask libunwind to get next frame (skip over first which is 553 // _Unwind_RaiseException or _Unwind_Resume). 554 // 555 // Resume only ever makes sense for 1 frame. 556 _Unwind_State state = 557 resume ? _US_UNWIND_FRAME_RESUME : _US_UNWIND_FRAME_STARTING; 558 if (resume && frame_count == 1) { 559 // On a resume, first unwind the _Unwind_Resume() frame. The next frame 560 // is now the landing pad for the cleanup from a previous execution of 561 // phase2. To continue unwindingly correctly, replace VRS[15] with the 562 // IP of the frame that the previous run of phase2 installed the context 563 // for. After this, continue unwinding as if normal. 564 // 565 // See #7.4.6 for details. 566 unw_set_reg(cursor, UNW_REG_IP, 567 exception_object->unwinder_cache.reserved2); 568 resume = false; 569 } 570 571 // Get info about this frame. 572 unw_word_t sp; 573 unw_proc_info_t frameInfo; 574 unw_get_reg(cursor, UNW_REG_SP, &sp); 575 if (unw_get_proc_info(cursor, &frameInfo) != UNW_ESUCCESS) { 576 _LIBUNWIND_TRACE_UNWINDING("unwind_phase2(ex_ojb=%p): unw_get_proc_info " 577 "failed => _URC_FATAL_PHASE2_ERROR", 578 static_cast<void *>(exception_object)); 579 return _URC_FATAL_PHASE2_ERROR; 580 } 581 582 // When tracing, print state information. 583 if (_LIBUNWIND_TRACING_UNWINDING) { 584 char functionBuf[512]; 585 const char *functionName = functionBuf; 586 unw_word_t offset; 587 if ((unw_get_proc_name(cursor, functionBuf, sizeof(functionBuf), 588 &offset) != UNW_ESUCCESS) || 589 (frameInfo.start_ip + offset > frameInfo.end_ip)) 590 functionName = ".anonymous."; 591 _LIBUNWIND_TRACE_UNWINDING( 592 "unwind_phase2(ex_ojb=%p): start_ip=0x%llX, func=%s, sp=0x%llX, " 593 "lsda=0x%llX, personality=0x%llX", 594 static_cast<void *>(exception_object), (long long)frameInfo.start_ip, 595 functionName, (long long)sp, (long long)frameInfo.lsda, 596 (long long)frameInfo.handler); 597 } 598 599 // If there is a personality routine, tell it we are unwinding. 600 if (frameInfo.handler != 0) { 601 __personality_routine p = 602 (__personality_routine)(long)(frameInfo.handler); 603 struct _Unwind_Context *context = (struct _Unwind_Context *)(cursor); 604 // EHABI #7.2 605 exception_object->pr_cache.fnstart = frameInfo.start_ip; 606 exception_object->pr_cache.ehtp = 607 (_Unwind_EHT_Header *)frameInfo.unwind_info; 608 exception_object->pr_cache.additional = frameInfo.flags; 609 _Unwind_Reason_Code personalityResult = 610 (*p)(state, exception_object, context); 611 switch (personalityResult) { 612 case _URC_CONTINUE_UNWIND: 613 // Continue unwinding 614 _LIBUNWIND_TRACE_UNWINDING( 615 "unwind_phase2(ex_ojb=%p): _URC_CONTINUE_UNWIND", 616 static_cast<void *>(exception_object)); 617 // EHABI #7.2 618 if (sp == exception_object->barrier_cache.sp) { 619 // Phase 1 said we would stop at this frame, but we did not... 620 _LIBUNWIND_ABORT("during phase1 personality function said it would " 621 "stop here, but now in phase2 it did not stop here"); 622 } 623 break; 624 case _URC_INSTALL_CONTEXT: 625 _LIBUNWIND_TRACE_UNWINDING( 626 "unwind_phase2(ex_ojb=%p): _URC_INSTALL_CONTEXT", 627 static_cast<void *>(exception_object)); 628 // Personality routine says to transfer control to landing pad. 629 // We may get control back if landing pad calls _Unwind_Resume(). 630 if (_LIBUNWIND_TRACING_UNWINDING) { 631 unw_word_t pc; 632 unw_get_reg(cursor, UNW_REG_IP, &pc); 633 unw_get_reg(cursor, UNW_REG_SP, &sp); 634 _LIBUNWIND_TRACE_UNWINDING("unwind_phase2(ex_ojb=%p): re-entering " 635 "user code with ip=0x%llX, sp=0x%llX", 636 static_cast<void *>(exception_object), 637 (long long)pc, (long long)sp); 638 } 639 640 { 641 // EHABI #7.4.1 says we need to preserve pc for when _Unwind_Resume 642 // is called back, to find this same frame. 643 unw_word_t pc; 644 unw_get_reg(cursor, UNW_REG_IP, &pc); 645 exception_object->unwinder_cache.reserved2 = (uint32_t)pc; 646 } 647 unw_resume(cursor); 648 // unw_resume() only returns if there was an error. 649 return _URC_FATAL_PHASE2_ERROR; 650 651 // # EHABI #7.4.3 652 case _URC_FAILURE: 653 abort(); 654 655 default: 656 // Personality routine returned an unknown result code. 657 _LIBUNWIND_DEBUG_LOG("personality function returned unknown result %d", 658 personalityResult); 659 return _URC_FATAL_PHASE2_ERROR; 660 } 661 } 662 frame_count++; 663 } 664 665 // Clean up phase did not resume at the frame that the search phase 666 // said it would... 667 return _URC_FATAL_PHASE2_ERROR; 668 } 669 670 /// Called by __cxa_throw. Only returns if there is a fatal error. 671 _LIBUNWIND_EXPORT _Unwind_Reason_Code 672 _Unwind_RaiseException(_Unwind_Exception *exception_object) { 673 _LIBUNWIND_TRACE_API("_Unwind_RaiseException(ex_obj=%p)", 674 static_cast<void *>(exception_object)); 675 unw_context_t uc; 676 unw_cursor_t cursor; 677 unw_getcontext(&uc); 678 679 // This field for is for compatibility with GCC to say this isn't a forced 680 // unwind. EHABI #7.2 681 exception_object->unwinder_cache.reserved1 = 0; 682 683 // phase 1: the search phase 684 _Unwind_Reason_Code phase1 = unwind_phase1(&uc, &cursor, exception_object); 685 if (phase1 != _URC_NO_REASON) 686 return phase1; 687 688 // phase 2: the clean up phase 689 return unwind_phase2(&uc, &cursor, exception_object, false); 690 } 691 692 _LIBUNWIND_EXPORT void _Unwind_Complete(_Unwind_Exception* exception_object) { 693 // This is to be called when exception handling completes to give us a chance 694 // to perform any housekeeping. EHABI #7.2. But we have nothing to do here. 695 (void)exception_object; 696 } 697 698 /// When _Unwind_RaiseException() is in phase2, it hands control 699 /// to the personality function at each frame. The personality 700 /// may force a jump to a landing pad in that function, the landing 701 /// pad code may then call _Unwind_Resume() to continue with the 702 /// unwinding. Note: the call to _Unwind_Resume() is from compiler 703 /// geneated user code. All other _Unwind_* routines are called 704 /// by the C++ runtime __cxa_* routines. 705 /// 706 /// Note: re-throwing an exception (as opposed to continuing the unwind) 707 /// is implemented by having the code call __cxa_rethrow() which 708 /// in turn calls _Unwind_Resume_or_Rethrow(). 709 _LIBUNWIND_EXPORT void 710 _Unwind_Resume(_Unwind_Exception *exception_object) { 711 _LIBUNWIND_TRACE_API("_Unwind_Resume(ex_obj=%p)", 712 static_cast<void *>(exception_object)); 713 unw_context_t uc; 714 unw_cursor_t cursor; 715 unw_getcontext(&uc); 716 717 // _Unwind_RaiseException on EHABI will always set the reserved1 field to 0, 718 // which is in the same position as private_1 below. 719 // TODO(ajwong): Who wronte the above? Why is it true? 720 unwind_phase2(&uc, &cursor, exception_object, true); 721 722 // Clients assume _Unwind_Resume() does not return, so all we can do is abort. 723 _LIBUNWIND_ABORT("_Unwind_Resume() can't return"); 724 } 725 726 /// Called by personality handler during phase 2 to get LSDA for current frame. 727 _LIBUNWIND_EXPORT uintptr_t 728 _Unwind_GetLanguageSpecificData(struct _Unwind_Context *context) { 729 unw_cursor_t *cursor = (unw_cursor_t *)context; 730 unw_proc_info_t frameInfo; 731 uintptr_t result = 0; 732 if (unw_get_proc_info(cursor, &frameInfo) == UNW_ESUCCESS) 733 result = (uintptr_t)frameInfo.lsda; 734 _LIBUNWIND_TRACE_API( 735 "_Unwind_GetLanguageSpecificData(context=%p) => 0x%llx", 736 static_cast<void *>(context), (long long)result); 737 return result; 738 } 739 740 static uint64_t ValueAsBitPattern(_Unwind_VRS_DataRepresentation representation, 741 void* valuep) { 742 uint64_t value = 0; 743 switch (representation) { 744 case _UVRSD_UINT32: 745 case _UVRSD_FLOAT: 746 memcpy(&value, valuep, sizeof(uint32_t)); 747 break; 748 749 case _UVRSD_VFPX: 750 case _UVRSD_UINT64: 751 case _UVRSD_DOUBLE: 752 memcpy(&value, valuep, sizeof(uint64_t)); 753 break; 754 } 755 return value; 756 } 757 758 _Unwind_VRS_Result 759 _Unwind_VRS_Set(_Unwind_Context *context, _Unwind_VRS_RegClass regclass, 760 uint32_t regno, _Unwind_VRS_DataRepresentation representation, 761 void *valuep) { 762 _LIBUNWIND_TRACE_API("_Unwind_VRS_Set(context=%p, regclass=%d, reg=%d, " 763 "rep=%d, value=0x%llX)", 764 static_cast<void *>(context), regclass, regno, 765 representation, 766 ValueAsBitPattern(representation, valuep)); 767 unw_cursor_t *cursor = (unw_cursor_t *)context; 768 switch (regclass) { 769 case _UVRSC_CORE: 770 if (representation != _UVRSD_UINT32 || regno > 15) 771 return _UVRSR_FAILED; 772 return unw_set_reg(cursor, (unw_regnum_t)(UNW_ARM_R0 + regno), 773 *(unw_word_t *)valuep) == UNW_ESUCCESS 774 ? _UVRSR_OK 775 : _UVRSR_FAILED; 776 case _UVRSC_VFP: 777 if (representation != _UVRSD_VFPX && representation != _UVRSD_DOUBLE) 778 return _UVRSR_FAILED; 779 if (representation == _UVRSD_VFPX) { 780 // Can only touch d0-15 with FSTMFDX. 781 if (regno > 15) 782 return _UVRSR_FAILED; 783 unw_save_vfp_as_X(cursor); 784 } else { 785 if (regno > 31) 786 return _UVRSR_FAILED; 787 } 788 return unw_set_fpreg(cursor, (unw_regnum_t)(UNW_ARM_D0 + regno), 789 *(unw_fpreg_t *)valuep) == UNW_ESUCCESS 790 ? _UVRSR_OK 791 : _UVRSR_FAILED; 792 #if defined(__ARM_WMMX) 793 case _UVRSC_WMMXC: 794 if (representation != _UVRSD_UINT32 || regno > 3) 795 return _UVRSR_FAILED; 796 return unw_set_reg(cursor, (unw_regnum_t)(UNW_ARM_WC0 + regno), 797 *(unw_word_t *)valuep) == UNW_ESUCCESS 798 ? _UVRSR_OK 799 : _UVRSR_FAILED; 800 case _UVRSC_WMMXD: 801 if (representation != _UVRSD_DOUBLE || regno > 31) 802 return _UVRSR_FAILED; 803 return unw_set_fpreg(cursor, (unw_regnum_t)(UNW_ARM_WR0 + regno), 804 *(unw_fpreg_t *)valuep) == UNW_ESUCCESS 805 ? _UVRSR_OK 806 : _UVRSR_FAILED; 807 #else 808 case _UVRSC_WMMXC: 809 case _UVRSC_WMMXD: 810 break; 811 #endif 812 } 813 _LIBUNWIND_ABORT("unsupported register class"); 814 } 815 816 static _Unwind_VRS_Result 817 _Unwind_VRS_Get_Internal(_Unwind_Context *context, 818 _Unwind_VRS_RegClass regclass, uint32_t regno, 819 _Unwind_VRS_DataRepresentation representation, 820 void *valuep) { 821 unw_cursor_t *cursor = (unw_cursor_t *)context; 822 switch (regclass) { 823 case _UVRSC_CORE: 824 if (representation != _UVRSD_UINT32 || regno > 15) 825 return _UVRSR_FAILED; 826 return unw_get_reg(cursor, (unw_regnum_t)(UNW_ARM_R0 + regno), 827 (unw_word_t *)valuep) == UNW_ESUCCESS 828 ? _UVRSR_OK 829 : _UVRSR_FAILED; 830 case _UVRSC_VFP: 831 if (representation != _UVRSD_VFPX && representation != _UVRSD_DOUBLE) 832 return _UVRSR_FAILED; 833 if (representation == _UVRSD_VFPX) { 834 // Can only touch d0-15 with FSTMFDX. 835 if (regno > 15) 836 return _UVRSR_FAILED; 837 unw_save_vfp_as_X(cursor); 838 } else { 839 if (regno > 31) 840 return _UVRSR_FAILED; 841 } 842 return unw_get_fpreg(cursor, (unw_regnum_t)(UNW_ARM_D0 + regno), 843 (unw_fpreg_t *)valuep) == UNW_ESUCCESS 844 ? _UVRSR_OK 845 : _UVRSR_FAILED; 846 #if defined(__ARM_WMMX) 847 case _UVRSC_WMMXC: 848 if (representation != _UVRSD_UINT32 || regno > 3) 849 return _UVRSR_FAILED; 850 return unw_get_reg(cursor, (unw_regnum_t)(UNW_ARM_WC0 + regno), 851 (unw_word_t *)valuep) == UNW_ESUCCESS 852 ? _UVRSR_OK 853 : _UVRSR_FAILED; 854 case _UVRSC_WMMXD: 855 if (representation != _UVRSD_DOUBLE || regno > 31) 856 return _UVRSR_FAILED; 857 return unw_get_fpreg(cursor, (unw_regnum_t)(UNW_ARM_WR0 + regno), 858 (unw_fpreg_t *)valuep) == UNW_ESUCCESS 859 ? _UVRSR_OK 860 : _UVRSR_FAILED; 861 #else 862 case _UVRSC_WMMXC: 863 case _UVRSC_WMMXD: 864 break; 865 #endif 866 } 867 _LIBUNWIND_ABORT("unsupported register class"); 868 } 869 870 _Unwind_VRS_Result _Unwind_VRS_Get( 871 _Unwind_Context *context, 872 _Unwind_VRS_RegClass regclass, 873 uint32_t regno, 874 _Unwind_VRS_DataRepresentation representation, 875 void *valuep) { 876 _Unwind_VRS_Result result = 877 _Unwind_VRS_Get_Internal(context, regclass, regno, representation, 878 valuep); 879 _LIBUNWIND_TRACE_API("_Unwind_VRS_Get(context=%p, regclass=%d, reg=%d, " 880 "rep=%d, value=0x%llX, result = %d)", 881 static_cast<void *>(context), regclass, regno, 882 representation, 883 ValueAsBitPattern(representation, valuep), result); 884 return result; 885 } 886 887 _Unwind_VRS_Result 888 _Unwind_VRS_Pop(_Unwind_Context *context, _Unwind_VRS_RegClass regclass, 889 uint32_t discriminator, 890 _Unwind_VRS_DataRepresentation representation) { 891 _LIBUNWIND_TRACE_API("_Unwind_VRS_Pop(context=%p, regclass=%d, " 892 "discriminator=%d, representation=%d)", 893 static_cast<void *>(context), regclass, discriminator, 894 representation); 895 switch (regclass) { 896 case _UVRSC_WMMXC: 897 #if !defined(__ARM_WMMX) 898 break; 899 #endif 900 case _UVRSC_CORE: { 901 if (representation != _UVRSD_UINT32) 902 return _UVRSR_FAILED; 903 // When popping SP from the stack, we don't want to override it from the 904 // computed new stack location. See EHABI #7.5.4 table 3. 905 bool poppedSP = false; 906 uint32_t* sp; 907 if (_Unwind_VRS_Get(context, _UVRSC_CORE, UNW_ARM_SP, 908 _UVRSD_UINT32, &sp) != _UVRSR_OK) { 909 return _UVRSR_FAILED; 910 } 911 for (uint32_t i = 0; i < 16; ++i) { 912 if (!(discriminator & static_cast<uint32_t>(1 << i))) 913 continue; 914 uint32_t value = *sp++; 915 if (regclass == _UVRSC_CORE && i == 13) 916 poppedSP = true; 917 if (_Unwind_VRS_Set(context, regclass, i, 918 _UVRSD_UINT32, &value) != _UVRSR_OK) { 919 return _UVRSR_FAILED; 920 } 921 } 922 if (!poppedSP) { 923 return _Unwind_VRS_Set(context, _UVRSC_CORE, UNW_ARM_SP, 924 _UVRSD_UINT32, &sp); 925 } 926 return _UVRSR_OK; 927 } 928 case _UVRSC_WMMXD: 929 #if !defined(__ARM_WMMX) 930 break; 931 #endif 932 case _UVRSC_VFP: { 933 if (representation != _UVRSD_VFPX && representation != _UVRSD_DOUBLE) 934 return _UVRSR_FAILED; 935 uint32_t first = discriminator >> 16; 936 uint32_t count = discriminator & 0xffff; 937 uint32_t end = first+count; 938 uint32_t* sp; 939 if (_Unwind_VRS_Get(context, _UVRSC_CORE, UNW_ARM_SP, 940 _UVRSD_UINT32, &sp) != _UVRSR_OK) { 941 return _UVRSR_FAILED; 942 } 943 // For _UVRSD_VFPX, we're assuming the data is stored in FSTMX "standard 944 // format 1", which is equivalent to FSTMD + a padding word. 945 for (uint32_t i = first; i < end; ++i) { 946 // SP is only 32-bit aligned so don't copy 64-bit at a time. 947 uint64_t value = *sp++; 948 value |= ((uint64_t)(*sp++)) << 32; 949 if (_Unwind_VRS_Set(context, regclass, i, representation, &value) != 950 _UVRSR_OK) 951 return _UVRSR_FAILED; 952 } 953 if (representation == _UVRSD_VFPX) 954 ++sp; 955 return _Unwind_VRS_Set(context, _UVRSC_CORE, UNW_ARM_SP, _UVRSD_UINT32, 956 &sp); 957 } 958 } 959 _LIBUNWIND_ABORT("unsupported register class"); 960 } 961 962 /// Called by personality handler during phase 2 to find the start of the 963 /// function. 964 _LIBUNWIND_EXPORT uintptr_t 965 _Unwind_GetRegionStart(struct _Unwind_Context *context) { 966 unw_cursor_t *cursor = (unw_cursor_t *)context; 967 unw_proc_info_t frameInfo; 968 uintptr_t result = 0; 969 if (unw_get_proc_info(cursor, &frameInfo) == UNW_ESUCCESS) 970 result = (uintptr_t)frameInfo.start_ip; 971 _LIBUNWIND_TRACE_API("_Unwind_GetRegionStart(context=%p) => 0x%llX", 972 static_cast<void *>(context), (long long)result); 973 return result; 974 } 975 976 977 /// Called by personality handler during phase 2 if a foreign exception 978 // is caught. 979 _LIBUNWIND_EXPORT void 980 _Unwind_DeleteException(_Unwind_Exception *exception_object) { 981 _LIBUNWIND_TRACE_API("_Unwind_DeleteException(ex_obj=%p)", 982 static_cast<void *>(exception_object)); 983 if (exception_object->exception_cleanup != NULL) 984 (*exception_object->exception_cleanup)(_URC_FOREIGN_EXCEPTION_CAUGHT, 985 exception_object); 986 } 987 988 extern "C" _LIBUNWIND_EXPORT _Unwind_Reason_Code 989 __gnu_unwind_frame(_Unwind_Exception *exception_object, 990 struct _Unwind_Context *context) { 991 unw_cursor_t *cursor = (unw_cursor_t *)context; 992 if (unw_step(cursor) != UNW_STEP_SUCCESS) 993 return _URC_FAILURE; 994 return _URC_OK; 995 } 996 997 #endif // _LIBUNWIND_ARM_EHABI 998