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 30namespace { 31 32// Strange order: take words in order, but inside word, take from most to least 33// signinficant byte. 34uint8_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 39const char* getNextWord(const char* data, uint32_t* out) { 40 *out = *reinterpret_cast<const uint32_t*>(data); 41 return data + 4; 42} 43 44const char* getNextNibble(const char* data, uint32_t* out) { 45 *out = *reinterpret_cast<const uint16_t*>(data); 46 return data + 2; 47} 48 49struct 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 163static _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. 191uint32_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. 197uint32_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 */ 211extern "C" const uint32_t* 212decode_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 case 0xc0: 355 case 0xc1: 356 case 0xc2: 357 case 0xc3: 358 case 0xc4: 359 case 0xc5: 360 _Unwind_VRS_Pop(context, _UVRSC_WMMXD, 361 RegisterRange(10, byte & 0x7), _UVRSD_DOUBLE); 362 break; 363 case 0xc6: { 364 uint8_t v = getByte(data, offset++); 365 uint8_t start = static_cast<uint8_t>(v >> 4); 366 uint8_t count_minus_one = v & 0xf; 367 if (start + count_minus_one >= 16) 368 return _URC_FAILURE; 369 _Unwind_VRS_Pop(context, _UVRSC_WMMXD, 370 RegisterRange(start, count_minus_one), 371 _UVRSD_DOUBLE); 372 break; 373 } 374 case 0xc7: { 375 uint8_t v = getByte(data, offset++); 376 if (!v || v & 0xf0) 377 return _URC_FAILURE; 378 _Unwind_VRS_Pop(context, _UVRSC_WMMXC, v, _UVRSD_DOUBLE); 379 break; 380 } 381 case 0xc8: 382 case 0xc9: { 383 uint8_t v = getByte(data, offset++); 384 uint8_t start = 385 static_cast<uint8_t>(((byte == 0xc8) ? 16 : 0) + (v >> 4)); 386 uint8_t count_minus_one = v & 0xf; 387 if (start + count_minus_one >= 32) 388 return _URC_FAILURE; 389 _Unwind_VRS_Pop(context, _UVRSC_VFP, 390 RegisterRange(start, count_minus_one), 391 _UVRSD_DOUBLE); 392 break; 393 } 394 default: 395 return _URC_FAILURE; 396 } 397 break; 398 } 399 case 0xd0: { 400 if (byte & 0x08) 401 return _URC_FAILURE; 402 _Unwind_VRS_Pop(context, _UVRSC_VFP, RegisterRange(8, byte & 0x7), 403 _UVRSD_DOUBLE); 404 break; 405 } 406 default: 407 return _URC_FAILURE; 408 } 409 } 410 } 411 if (!wrotePC) { 412 uint32_t lr; 413 _Unwind_VRS_Get(context, _UVRSC_CORE, UNW_ARM_LR, _UVRSD_UINT32, &lr); 414 _Unwind_VRS_Set(context, _UVRSC_CORE, UNW_ARM_IP, _UVRSD_UINT32, &lr); 415 } 416 return _URC_CONTINUE_UNWIND; 417} 418 419extern "C" _Unwind_Reason_Code __aeabi_unwind_cpp_pr0( 420 _Unwind_State state, 421 _Unwind_Control_Block *ucbp, 422 _Unwind_Context *context) { 423 return unwindOneFrame(state, ucbp, context); 424} 425 426extern "C" _Unwind_Reason_Code __aeabi_unwind_cpp_pr1( 427 _Unwind_State state, 428 _Unwind_Control_Block *ucbp, 429 _Unwind_Context *context) { 430 return unwindOneFrame(state, ucbp, context); 431} 432 433extern "C" _Unwind_Reason_Code __aeabi_unwind_cpp_pr2( 434 _Unwind_State state, 435 _Unwind_Control_Block *ucbp, 436 _Unwind_Context *context) { 437 return unwindOneFrame(state, ucbp, context); 438} 439 440static _Unwind_Reason_Code 441unwind_phase1(unw_context_t *uc, unw_cursor_t *cursor, _Unwind_Exception *exception_object) { 442 // EHABI #7.3 discusses preserving the VRS in a "temporary VRS" during 443 // phase 1 and then restoring it to the "primary VRS" for phase 2. The 444 // effect is phase 2 doesn't see any of the VRS manipulations from phase 1. 445 // In this implementation, the phases don't share the VRS backing store. 446 // Instead, they are passed the original |uc| and they create a new VRS 447 // from scratch thus achieving the same effect. 448 unw_init_local(cursor, uc); 449 450 // Walk each frame looking for a place to stop. 451 for (bool handlerNotFound = true; handlerNotFound;) { 452 453 // See if frame has code to run (has personality routine). 454 unw_proc_info_t frameInfo; 455 if (unw_get_proc_info(cursor, &frameInfo) != UNW_ESUCCESS) { 456 _LIBUNWIND_TRACE_UNWINDING("unwind_phase1(ex_ojb=%p): unw_get_proc_info " 457 "failed => _URC_FATAL_PHASE1_ERROR\n", 458 static_cast<void *>(exception_object)); 459 return _URC_FATAL_PHASE1_ERROR; 460 } 461 462 // When tracing, print state information. 463 if (_LIBUNWIND_TRACING_UNWINDING) { 464 char functionBuf[512]; 465 const char *functionName = functionBuf; 466 unw_word_t offset; 467 if ((unw_get_proc_name(cursor, functionBuf, sizeof(functionBuf), 468 &offset) != UNW_ESUCCESS) || 469 (frameInfo.start_ip + offset > frameInfo.end_ip)) 470 functionName = ".anonymous."; 471 unw_word_t pc; 472 unw_get_reg(cursor, UNW_REG_IP, &pc); 473 _LIBUNWIND_TRACE_UNWINDING( 474 "unwind_phase1(ex_ojb=%p): pc=0x%llX, start_ip=0x%llX, func=%s, " 475 "lsda=0x%llX, personality=0x%llX\n", 476 static_cast<void *>(exception_object), (long long)pc, 477 (long long)frameInfo.start_ip, functionName, 478 (long long)frameInfo.lsda, (long long)frameInfo.handler); 479 } 480 481 // If there is a personality routine, ask it if it will want to stop at 482 // this frame. 483 if (frameInfo.handler != 0) { 484 __personality_routine p = 485 (__personality_routine)(long)(frameInfo.handler); 486 _LIBUNWIND_TRACE_UNWINDING( 487 "unwind_phase1(ex_ojb=%p): calling personality function %p\n", 488 static_cast<void *>(exception_object), 489 reinterpret_cast<void *>(reinterpret_cast<uintptr_t>(p))); 490 struct _Unwind_Context *context = (struct _Unwind_Context *)(cursor); 491 exception_object->pr_cache.fnstart = frameInfo.start_ip; 492 exception_object->pr_cache.ehtp = 493 (_Unwind_EHT_Header *)frameInfo.unwind_info; 494 exception_object->pr_cache.additional = frameInfo.flags; 495 _Unwind_Reason_Code personalityResult = 496 (*p)(_US_VIRTUAL_UNWIND_FRAME, exception_object, context); 497 _LIBUNWIND_TRACE_UNWINDING( 498 "unwind_phase1(ex_ojb=%p): personality result %d start_ip %x ehtp %p " 499 "additional %x\n", 500 static_cast<void *>(exception_object), personalityResult, 501 exception_object->pr_cache.fnstart, 502 static_cast<void *>(exception_object->pr_cache.ehtp), 503 exception_object->pr_cache.additional); 504 switch (personalityResult) { 505 case _URC_HANDLER_FOUND: 506 // found a catch clause or locals that need destructing in this frame 507 // stop search and remember stack pointer at the frame 508 handlerNotFound = false; 509 // p should have initialized barrier_cache. EHABI #7.3.5 510 _LIBUNWIND_TRACE_UNWINDING( 511 "unwind_phase1(ex_ojb=%p): _URC_HANDLER_FOUND \n", 512 static_cast<void *>(exception_object)); 513 return _URC_NO_REASON; 514 515 case _URC_CONTINUE_UNWIND: 516 _LIBUNWIND_TRACE_UNWINDING( 517 "unwind_phase1(ex_ojb=%p): _URC_CONTINUE_UNWIND\n", 518 static_cast<void *>(exception_object)); 519 // continue unwinding 520 break; 521 522 // EHABI #7.3.3 523 case _URC_FAILURE: 524 return _URC_FAILURE; 525 526 default: 527 // something went wrong 528 _LIBUNWIND_TRACE_UNWINDING( 529 "unwind_phase1(ex_ojb=%p): _URC_FATAL_PHASE1_ERROR\n", 530 static_cast<void *>(exception_object)); 531 return _URC_FATAL_PHASE1_ERROR; 532 } 533 } 534 } 535 return _URC_NO_REASON; 536} 537 538static _Unwind_Reason_Code unwind_phase2(unw_context_t *uc, unw_cursor_t *cursor, 539 _Unwind_Exception *exception_object, 540 bool resume) { 541 // See comment at the start of unwind_phase1 regarding VRS integrity. 542 unw_init_local(cursor, uc); 543 544 _LIBUNWIND_TRACE_UNWINDING("unwind_phase2(ex_ojb=%p)\n", 545 static_cast<void *>(exception_object)); 546 int frame_count = 0; 547 548 // Walk each frame until we reach where search phase said to stop. 549 while (true) { 550 // Ask libuwind to get next frame (skip over first which is 551 // _Unwind_RaiseException or _Unwind_Resume). 552 // 553 // Resume only ever makes sense for 1 frame. 554 _Unwind_State state = 555 resume ? _US_UNWIND_FRAME_RESUME : _US_UNWIND_FRAME_STARTING; 556 if (resume && frame_count == 1) { 557 // On a resume, first unwind the _Unwind_Resume() frame. The next frame 558 // is now the landing pad for the cleanup from a previous execution of 559 // phase2. To continue unwindingly correctly, replace VRS[15] with the 560 // IP of the frame that the previous run of phase2 installed the context 561 // for. After this, continue unwinding as if normal. 562 // 563 // See #7.4.6 for details. 564 unw_set_reg(cursor, UNW_REG_IP, 565 exception_object->unwinder_cache.reserved2); 566 resume = false; 567 } 568 569 // Get info about this frame. 570 unw_word_t sp; 571 unw_proc_info_t frameInfo; 572 unw_get_reg(cursor, UNW_REG_SP, &sp); 573 if (unw_get_proc_info(cursor, &frameInfo) != UNW_ESUCCESS) { 574 _LIBUNWIND_TRACE_UNWINDING("unwind_phase2(ex_ojb=%p): unw_get_proc_info " 575 "failed => _URC_FATAL_PHASE2_ERROR\n", 576 static_cast<void *>(exception_object)); 577 return _URC_FATAL_PHASE2_ERROR; 578 } 579 580 // When tracing, print state information. 581 if (_LIBUNWIND_TRACING_UNWINDING) { 582 char functionBuf[512]; 583 const char *functionName = functionBuf; 584 unw_word_t offset; 585 if ((unw_get_proc_name(cursor, functionBuf, sizeof(functionBuf), 586 &offset) != UNW_ESUCCESS) || 587 (frameInfo.start_ip + offset > frameInfo.end_ip)) 588 functionName = ".anonymous."; 589 _LIBUNWIND_TRACE_UNWINDING( 590 "unwind_phase2(ex_ojb=%p): start_ip=0x%llX, func=%s, sp=0x%llX, " 591 "lsda=0x%llX, personality=0x%llX\n", 592 static_cast<void *>(exception_object), (long long)frameInfo.start_ip, 593 functionName, (long long)sp, (long long)frameInfo.lsda, 594 (long long)frameInfo.handler); 595 } 596 597 // If there is a personality routine, tell it we are unwinding. 598 if (frameInfo.handler != 0) { 599 __personality_routine p = 600 (__personality_routine)(long)(frameInfo.handler); 601 struct _Unwind_Context *context = (struct _Unwind_Context *)(cursor); 602 // EHABI #7.2 603 exception_object->pr_cache.fnstart = frameInfo.start_ip; 604 exception_object->pr_cache.ehtp = 605 (_Unwind_EHT_Header *)frameInfo.unwind_info; 606 exception_object->pr_cache.additional = frameInfo.flags; 607 _Unwind_Reason_Code personalityResult = 608 (*p)(state, exception_object, context); 609 switch (personalityResult) { 610 case _URC_CONTINUE_UNWIND: 611 // Continue unwinding 612 _LIBUNWIND_TRACE_UNWINDING( 613 "unwind_phase2(ex_ojb=%p): _URC_CONTINUE_UNWIND\n", 614 static_cast<void *>(exception_object)); 615 // EHABI #7.2 616 if (sp == exception_object->barrier_cache.sp) { 617 // Phase 1 said we would stop at this frame, but we did not... 618 _LIBUNWIND_ABORT("during phase1 personality function said it would " 619 "stop here, but now in phase2 it did not stop here"); 620 } 621 break; 622 case _URC_INSTALL_CONTEXT: 623 _LIBUNWIND_TRACE_UNWINDING( 624 "unwind_phase2(ex_ojb=%p): _URC_INSTALL_CONTEXT\n", 625 static_cast<void *>(exception_object)); 626 // Personality routine says to transfer control to landing pad. 627 // We may get control back if landing pad calls _Unwind_Resume(). 628 if (_LIBUNWIND_TRACING_UNWINDING) { 629 unw_word_t pc; 630 unw_get_reg(cursor, UNW_REG_IP, &pc); 631 unw_get_reg(cursor, UNW_REG_SP, &sp); 632 _LIBUNWIND_TRACE_UNWINDING("unwind_phase2(ex_ojb=%p): re-entering " 633 "user code with ip=0x%llX, sp=0x%llX\n", 634 static_cast<void *>(exception_object), 635 (long long)pc, (long long)sp); 636 } 637 638 { 639 // EHABI #7.4.1 says we need to preserve pc for when _Unwind_Resume 640 // is called back, to find this same frame. 641 unw_word_t pc; 642 unw_get_reg(cursor, UNW_REG_IP, &pc); 643 exception_object->unwinder_cache.reserved2 = (uint32_t)pc; 644 } 645 unw_resume(cursor); 646 // unw_resume() only returns if there was an error. 647 return _URC_FATAL_PHASE2_ERROR; 648 649 // # EHABI #7.4.3 650 case _URC_FAILURE: 651 abort(); 652 653 default: 654 // Personality routine returned an unknown result code. 655 _LIBUNWIND_DEBUG_LOG("personality function returned unknown result %d", 656 personalityResult); 657 return _URC_FATAL_PHASE2_ERROR; 658 } 659 } 660 frame_count++; 661 } 662 663 // Clean up phase did not resume at the frame that the search phase 664 // said it would... 665 return _URC_FATAL_PHASE2_ERROR; 666} 667 668/// Called by __cxa_throw. Only returns if there is a fatal error. 669_LIBUNWIND_EXPORT _Unwind_Reason_Code 670_Unwind_RaiseException(_Unwind_Exception *exception_object) { 671 _LIBUNWIND_TRACE_API("_Unwind_RaiseException(ex_obj=%p)\n", 672 static_cast<void *>(exception_object)); 673 unw_context_t uc; 674 unw_cursor_t cursor; 675 unw_getcontext(&uc); 676 677 // This field for is for compatibility with GCC to say this isn't a forced 678 // unwind. EHABI #7.2 679 exception_object->unwinder_cache.reserved1 = 0; 680 681 // phase 1: the search phase 682 _Unwind_Reason_Code phase1 = unwind_phase1(&uc, &cursor, exception_object); 683 if (phase1 != _URC_NO_REASON) 684 return phase1; 685 686 // phase 2: the clean up phase 687 return unwind_phase2(&uc, &cursor, exception_object, false); 688} 689 690_LIBUNWIND_EXPORT void _Unwind_Complete(_Unwind_Exception* exception_object) { 691 // This is to be called when exception handling completes to give us a chance 692 // to perform any housekeeping. EHABI #7.2. But we have nothing to do here. 693 (void)exception_object; 694} 695 696/// When _Unwind_RaiseException() is in phase2, it hands control 697/// to the personality function at each frame. The personality 698/// may force a jump to a landing pad in that function, the landing 699/// pad code may then call _Unwind_Resume() to continue with the 700/// unwinding. Note: the call to _Unwind_Resume() is from compiler 701/// geneated user code. All other _Unwind_* routines are called 702/// by the C++ runtime __cxa_* routines. 703/// 704/// Note: re-throwing an exception (as opposed to continuing the unwind) 705/// is implemented by having the code call __cxa_rethrow() which 706/// in turn calls _Unwind_Resume_or_Rethrow(). 707_LIBUNWIND_EXPORT void 708_Unwind_Resume(_Unwind_Exception *exception_object) { 709 _LIBUNWIND_TRACE_API("_Unwind_Resume(ex_obj=%p)\n", 710 static_cast<void *>(exception_object)); 711 unw_context_t uc; 712 unw_cursor_t cursor; 713 unw_getcontext(&uc); 714 715 // _Unwind_RaiseException on EHABI will always set the reserved1 field to 0, 716 // which is in the same position as private_1 below. 717 // TODO(ajwong): Who wronte the above? Why is it true? 718 unwind_phase2(&uc, &cursor, exception_object, true); 719 720 // Clients assume _Unwind_Resume() does not return, so all we can do is abort. 721 _LIBUNWIND_ABORT("_Unwind_Resume() can't return"); 722} 723 724/// Called by personality handler during phase 2 to get LSDA for current frame. 725_LIBUNWIND_EXPORT uintptr_t 726_Unwind_GetLanguageSpecificData(struct _Unwind_Context *context) { 727 unw_cursor_t *cursor = (unw_cursor_t *)context; 728 unw_proc_info_t frameInfo; 729 uintptr_t result = 0; 730 if (unw_get_proc_info(cursor, &frameInfo) == UNW_ESUCCESS) 731 result = (uintptr_t)frameInfo.lsda; 732 _LIBUNWIND_TRACE_API( 733 "_Unwind_GetLanguageSpecificData(context=%p) => 0x%llx\n", 734 static_cast<void *>(context), (long long)result); 735 return result; 736} 737 738static uint64_t ValueAsBitPattern(_Unwind_VRS_DataRepresentation representation, 739 void* valuep) { 740 uint64_t value = 0; 741 switch (representation) { 742 case _UVRSD_UINT32: 743 case _UVRSD_FLOAT: 744 memcpy(&value, valuep, sizeof(uint32_t)); 745 break; 746 747 case _UVRSD_VFPX: 748 case _UVRSD_UINT64: 749 case _UVRSD_DOUBLE: 750 memcpy(&value, valuep, sizeof(uint64_t)); 751 break; 752 } 753 return value; 754} 755 756_Unwind_VRS_Result 757_Unwind_VRS_Set(_Unwind_Context *context, _Unwind_VRS_RegClass regclass, 758 uint32_t regno, _Unwind_VRS_DataRepresentation representation, 759 void *valuep) { 760 _LIBUNWIND_TRACE_API("_Unwind_VRS_Set(context=%p, regclass=%d, reg=%d, " 761 "rep=%d, value=0x%llX)\n", 762 static_cast<void *>(context), regclass, regno, 763 representation, 764 ValueAsBitPattern(representation, valuep)); 765 unw_cursor_t *cursor = (unw_cursor_t *)context; 766 switch (regclass) { 767 case _UVRSC_CORE: 768 if (representation != _UVRSD_UINT32 || regno > 15) 769 return _UVRSR_FAILED; 770 return unw_set_reg(cursor, (unw_regnum_t)(UNW_ARM_R0 + regno), 771 *(unw_word_t *)valuep) == UNW_ESUCCESS 772 ? _UVRSR_OK 773 : _UVRSR_FAILED; 774 case _UVRSC_WMMXC: 775 if (representation != _UVRSD_UINT32 || regno > 3) 776 return _UVRSR_FAILED; 777 return unw_set_reg(cursor, (unw_regnum_t)(UNW_ARM_WC0 + regno), 778 *(unw_word_t *)valuep) == UNW_ESUCCESS 779 ? _UVRSR_OK 780 : _UVRSR_FAILED; 781 case _UVRSC_VFP: 782 if (representation != _UVRSD_VFPX && representation != _UVRSD_DOUBLE) 783 return _UVRSR_FAILED; 784 if (representation == _UVRSD_VFPX) { 785 // Can only touch d0-15 with FSTMFDX. 786 if (regno > 15) 787 return _UVRSR_FAILED; 788 unw_save_vfp_as_X(cursor); 789 } else { 790 if (regno > 31) 791 return _UVRSR_FAILED; 792 } 793 return unw_set_fpreg(cursor, (unw_regnum_t)(UNW_ARM_D0 + regno), 794 *(unw_fpreg_t *)valuep) == UNW_ESUCCESS 795 ? _UVRSR_OK 796 : _UVRSR_FAILED; 797 case _UVRSC_WMMXD: 798 if (representation != _UVRSD_DOUBLE || regno > 31) 799 return _UVRSR_FAILED; 800 return unw_set_fpreg(cursor, (unw_regnum_t)(UNW_ARM_WR0 + regno), 801 *(unw_fpreg_t *)valuep) == UNW_ESUCCESS 802 ? _UVRSR_OK 803 : _UVRSR_FAILED; 804 } 805 _LIBUNWIND_ABORT("unsupported register class"); 806} 807 808static _Unwind_VRS_Result 809_Unwind_VRS_Get_Internal(_Unwind_Context *context, 810 _Unwind_VRS_RegClass regclass, uint32_t regno, 811 _Unwind_VRS_DataRepresentation representation, 812 void *valuep) { 813 unw_cursor_t *cursor = (unw_cursor_t *)context; 814 switch (regclass) { 815 case _UVRSC_CORE: 816 if (representation != _UVRSD_UINT32 || regno > 15) 817 return _UVRSR_FAILED; 818 return unw_get_reg(cursor, (unw_regnum_t)(UNW_ARM_R0 + regno), 819 (unw_word_t *)valuep) == UNW_ESUCCESS 820 ? _UVRSR_OK 821 : _UVRSR_FAILED; 822 case _UVRSC_WMMXC: 823 if (representation != _UVRSD_UINT32 || regno > 3) 824 return _UVRSR_FAILED; 825 return unw_get_reg(cursor, (unw_regnum_t)(UNW_ARM_WC0 + regno), 826 (unw_word_t *)valuep) == UNW_ESUCCESS 827 ? _UVRSR_OK 828 : _UVRSR_FAILED; 829 case _UVRSC_VFP: 830 if (representation != _UVRSD_VFPX && representation != _UVRSD_DOUBLE) 831 return _UVRSR_FAILED; 832 if (representation == _UVRSD_VFPX) { 833 // Can only touch d0-15 with FSTMFDX. 834 if (regno > 15) 835 return _UVRSR_FAILED; 836 unw_save_vfp_as_X(cursor); 837 } else { 838 if (regno > 31) 839 return _UVRSR_FAILED; 840 } 841 return unw_get_fpreg(cursor, (unw_regnum_t)(UNW_ARM_D0 + regno), 842 (unw_fpreg_t *)valuep) == UNW_ESUCCESS 843 ? _UVRSR_OK 844 : _UVRSR_FAILED; 845 case _UVRSC_WMMXD: 846 if (representation != _UVRSD_DOUBLE || regno > 31) 847 return _UVRSR_FAILED; 848 return unw_get_fpreg(cursor, (unw_regnum_t)(UNW_ARM_WR0 + regno), 849 (unw_fpreg_t *)valuep) == UNW_ESUCCESS 850 ? _UVRSR_OK 851 : _UVRSR_FAILED; 852 } 853 _LIBUNWIND_ABORT("unsupported register class"); 854} 855 856_Unwind_VRS_Result _Unwind_VRS_Get( 857 _Unwind_Context *context, 858 _Unwind_VRS_RegClass regclass, 859 uint32_t regno, 860 _Unwind_VRS_DataRepresentation representation, 861 void *valuep) { 862 _Unwind_VRS_Result result = 863 _Unwind_VRS_Get_Internal(context, regclass, regno, representation, 864 valuep); 865 _LIBUNWIND_TRACE_API("_Unwind_VRS_Get(context=%p, regclass=%d, reg=%d, " 866 "rep=%d, value=0x%llX, result = %d)\n", 867 static_cast<void *>(context), regclass, regno, 868 representation, 869 ValueAsBitPattern(representation, valuep), result); 870 return result; 871} 872 873_Unwind_VRS_Result 874_Unwind_VRS_Pop(_Unwind_Context *context, _Unwind_VRS_RegClass regclass, 875 uint32_t discriminator, 876 _Unwind_VRS_DataRepresentation representation) { 877 _LIBUNWIND_TRACE_API("_Unwind_VRS_Pop(context=%p, regclass=%d, " 878 "discriminator=%d, representation=%d)\n", 879 static_cast<void *>(context), regclass, discriminator, 880 representation); 881 switch (regclass) { 882 case _UVRSC_CORE: 883 case _UVRSC_WMMXC: { 884 if (representation != _UVRSD_UINT32) 885 return _UVRSR_FAILED; 886 // When popping SP from the stack, we don't want to override it from the 887 // computed new stack location. See EHABI #7.5.4 table 3. 888 bool poppedSP = false; 889 uint32_t* sp; 890 if (_Unwind_VRS_Get(context, _UVRSC_CORE, UNW_ARM_SP, 891 _UVRSD_UINT32, &sp) != _UVRSR_OK) { 892 return _UVRSR_FAILED; 893 } 894 for (uint32_t i = 0; i < 16; ++i) { 895 if (!(discriminator & static_cast<uint32_t>(1 << i))) 896 continue; 897 uint32_t value = *sp++; 898 if (regclass == _UVRSC_CORE && i == 13) 899 poppedSP = true; 900 if (_Unwind_VRS_Set(context, regclass, i, 901 _UVRSD_UINT32, &value) != _UVRSR_OK) { 902 return _UVRSR_FAILED; 903 } 904 } 905 if (!poppedSP) { 906 return _Unwind_VRS_Set(context, _UVRSC_CORE, UNW_ARM_SP, 907 _UVRSD_UINT32, &sp); 908 } 909 return _UVRSR_OK; 910 } 911 case _UVRSC_VFP: 912 case _UVRSC_WMMXD: { 913 if (representation != _UVRSD_VFPX && representation != _UVRSD_DOUBLE) 914 return _UVRSR_FAILED; 915 uint32_t first = discriminator >> 16; 916 uint32_t count = discriminator & 0xffff; 917 uint32_t end = first+count; 918 uint32_t* sp; 919 if (_Unwind_VRS_Get(context, _UVRSC_CORE, UNW_ARM_SP, 920 _UVRSD_UINT32, &sp) != _UVRSR_OK) { 921 return _UVRSR_FAILED; 922 } 923 // For _UVRSD_VFPX, we're assuming the data is stored in FSTMX "standard 924 // format 1", which is equivalent to FSTMD + a padding word. 925 for (uint32_t i = first; i < end; ++i) { 926 // SP is only 32-bit aligned so don't copy 64-bit at a time. 927 uint64_t value = *sp++; 928 value |= ((uint64_t)(*sp++)) << 32; 929 if (_Unwind_VRS_Set(context, regclass, i, representation, &value) != 930 _UVRSR_OK) 931 return _UVRSR_FAILED; 932 } 933 if (representation == _UVRSD_VFPX) 934 ++sp; 935 return _Unwind_VRS_Set(context, _UVRSC_CORE, UNW_ARM_SP, _UVRSD_UINT32, 936 &sp); 937 } 938 } 939 _LIBUNWIND_ABORT("unsupported register class"); 940} 941 942/// Called by personality handler during phase 2 to find the start of the 943/// function. 944_LIBUNWIND_EXPORT uintptr_t 945_Unwind_GetRegionStart(struct _Unwind_Context *context) { 946 unw_cursor_t *cursor = (unw_cursor_t *)context; 947 unw_proc_info_t frameInfo; 948 uintptr_t result = 0; 949 if (unw_get_proc_info(cursor, &frameInfo) == UNW_ESUCCESS) 950 result = (uintptr_t)frameInfo.start_ip; 951 _LIBUNWIND_TRACE_API("_Unwind_GetRegionStart(context=%p) => 0x%llX\n", 952 static_cast<void *>(context), (long long)result); 953 return result; 954} 955 956 957/// Called by personality handler during phase 2 if a foreign exception 958// is caught. 959_LIBUNWIND_EXPORT void 960_Unwind_DeleteException(_Unwind_Exception *exception_object) { 961 _LIBUNWIND_TRACE_API("_Unwind_DeleteException(ex_obj=%p)\n", 962 static_cast<void *>(exception_object)); 963 if (exception_object->exception_cleanup != NULL) 964 (*exception_object->exception_cleanup)(_URC_FOREIGN_EXCEPTION_CAUGHT, 965 exception_object); 966} 967 968extern "C" _LIBUNWIND_EXPORT _Unwind_Reason_Code 969__gnu_unwind_frame(_Unwind_Exception *exception_object, 970 struct _Unwind_Context *context) { 971 unw_cursor_t *cursor = (unw_cursor_t *)context; 972 if (unw_step(cursor) != UNW_STEP_SUCCESS) 973 return _URC_FAILURE; 974 return _URC_OK; 975} 976 977#endif // _LIBUNWIND_ARM_EHABI 978