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 28 namespace { 29 30 // Strange order: take words in order, but inside word, take from most to least 31 // signinficant byte. 32 uint8_t getByte(const uint32_t* data, size_t offset) { 33 const uint8_t* byteData = reinterpret_cast<const uint8_t*>(data); 34 #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ 35 return byteData[(offset & ~(size_t)0x03) + (3 - (offset & (size_t)0x03))]; 36 #elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__ 37 return byteData[offset]; 38 #else 39 #error "Unable to determine endianess" 40 #endif 41 } 42 43 const char* getNextWord(const char* data, uint32_t* out) { 44 *out = *reinterpret_cast<const uint32_t*>(data); 45 return data + 4; 46 } 47 48 const char* getNextNibble(const char* data, uint32_t* out) { 49 *out = *reinterpret_cast<const uint16_t*>(data); 50 return data + 2; 51 } 52 53 struct Descriptor { 54 // See # 9.2 55 typedef enum { 56 SU16 = 0, // Short descriptor, 16-bit entries 57 LU16 = 1, // Long descriptor, 16-bit entries 58 LU32 = 3, // Long descriptor, 32-bit entries 59 RESERVED0 = 4, RESERVED1 = 5, RESERVED2 = 6, RESERVED3 = 7, 60 RESERVED4 = 8, RESERVED5 = 9, RESERVED6 = 10, RESERVED7 = 11, 61 RESERVED8 = 12, RESERVED9 = 13, RESERVED10 = 14, RESERVED11 = 15 62 } Format; 63 64 // See # 9.2 65 typedef enum { 66 CLEANUP = 0x0, 67 FUNC = 0x1, 68 CATCH = 0x2, 69 INVALID = 0x4 70 } Kind; 71 }; 72 73 _Unwind_Reason_Code ProcessDescriptors( 74 _Unwind_State state, 75 _Unwind_Control_Block* ucbp, 76 struct _Unwind_Context* context, 77 Descriptor::Format format, 78 const char* descriptorStart, 79 uint32_t flags) { 80 81 // EHT is inlined in the index using compact form. No descriptors. #5 82 if (flags & 0x1) 83 return _URC_CONTINUE_UNWIND; 84 85 // TODO: We should check the state here, and determine whether we need to 86 // perform phase1 or phase2 unwinding. 87 (void)state; 88 89 const char* descriptor = descriptorStart; 90 uint32_t descriptorWord; 91 getNextWord(descriptor, &descriptorWord); 92 while (descriptorWord) { 93 // Read descriptor based on # 9.2. 94 uint32_t length; 95 uint32_t offset; 96 switch (format) { 97 case Descriptor::LU32: 98 descriptor = getNextWord(descriptor, &length); 99 descriptor = getNextWord(descriptor, &offset); 100 break; 101 case Descriptor::LU16: 102 descriptor = getNextNibble(descriptor, &length); 103 descriptor = getNextNibble(descriptor, &offset); 104 break; 105 default: 106 assert(false); 107 return _URC_FAILURE; 108 } 109 110 // See # 9.2 table for decoding the kind of descriptor. It's a 2-bit value. 111 Descriptor::Kind kind = 112 static_cast<Descriptor::Kind>((length & 0x1) | ((offset & 0x1) << 1)); 113 114 // Clear off flag from last bit. 115 length &= ~1u; 116 offset &= ~1u; 117 uintptr_t scopeStart = ucbp->pr_cache.fnstart + offset; 118 uintptr_t scopeEnd = scopeStart + length; 119 uintptr_t pc = _Unwind_GetIP(context); 120 bool isInScope = (scopeStart <= pc) && (pc < scopeEnd); 121 122 switch (kind) { 123 case Descriptor::CLEANUP: { 124 // TODO(ajwong): Handle cleanup descriptors. 125 break; 126 } 127 case Descriptor::FUNC: { 128 // TODO(ajwong): Handle function descriptors. 129 break; 130 } 131 case Descriptor::CATCH: { 132 // Catch descriptors require gobbling one more word. 133 uint32_t landing_pad; 134 descriptor = getNextWord(descriptor, &landing_pad); 135 136 if (isInScope) { 137 // TODO(ajwong): This is only phase1 compatible logic. Implement 138 // phase2. 139 landing_pad = signExtendPrel31(landing_pad & ~0x80000000); 140 if (landing_pad == 0xffffffff) { 141 return _URC_HANDLER_FOUND; 142 } else if (landing_pad == 0xfffffffe) { 143 return _URC_FAILURE; 144 } else { 145 /* 146 bool is_reference_type = landing_pad & 0x80000000; 147 void* matched_object; 148 if (__cxxabiv1::__cxa_type_match( 149 ucbp, reinterpret_cast<const std::type_info *>(landing_pad), 150 is_reference_type, 151 &matched_object) != __cxxabiv1::ctm_failed) 152 return _URC_HANDLER_FOUND; 153 */ 154 _LIBUNWIND_ABORT("Type matching not implemented"); 155 } 156 } 157 break; 158 } 159 default: 160 _LIBUNWIND_ABORT("Invalid descriptor kind found."); 161 } 162 163 getNextWord(descriptor, &descriptorWord); 164 } 165 166 return _URC_CONTINUE_UNWIND; 167 } 168 169 static _Unwind_Reason_Code unwindOneFrame(_Unwind_State state, 170 _Unwind_Control_Block* ucbp, 171 struct _Unwind_Context* context) { 172 // Read the compact model EHT entry's header # 6.3 173 const uint32_t* unwindingData = ucbp->pr_cache.ehtp; 174 assert((*unwindingData & 0xf0000000) == 0x80000000 && "Must be a compact entry"); 175 Descriptor::Format format = 176 static_cast<Descriptor::Format>((*unwindingData & 0x0f000000) >> 24); 177 178 const char *lsda = 179 reinterpret_cast<const char *>(_Unwind_GetLanguageSpecificData(context)); 180 181 // Handle descriptors before unwinding so they are processed in the context 182 // of the correct stack frame. 183 _Unwind_Reason_Code result = 184 ProcessDescriptors(state, ucbp, context, format, lsda, 185 ucbp->pr_cache.additional); 186 187 if (result != _URC_CONTINUE_UNWIND) 188 return result; 189 190 if (__unw_step(reinterpret_cast<unw_cursor_t *>(context)) != UNW_STEP_SUCCESS) 191 return _URC_FAILURE; 192 return _URC_CONTINUE_UNWIND; 193 } 194 195 // Generates mask discriminator for _Unwind_VRS_Pop, e.g. for _UVRSC_CORE / 196 // _UVRSD_UINT32. 197 uint32_t RegisterMask(uint8_t start, uint8_t count_minus_one) { 198 return ((1U << (count_minus_one + 1)) - 1) << start; 199 } 200 201 // Generates mask discriminator for _Unwind_VRS_Pop, e.g. for _UVRSC_VFP / 202 // _UVRSD_DOUBLE. 203 uint32_t RegisterRange(uint8_t start, uint8_t count_minus_one) { 204 return ((uint32_t)start << 16) | ((uint32_t)count_minus_one + 1); 205 } 206 207 } // end anonymous namespace 208 209 /** 210 * Decodes an EHT entry. 211 * 212 * @param data Pointer to EHT. 213 * @param[out] off Offset from return value (in bytes) to begin interpretation. 214 * @param[out] len Number of bytes in unwind code. 215 * @return Pointer to beginning of unwind code. 216 */ 217 extern "C" const uint32_t* 218 decode_eht_entry(const uint32_t* data, size_t* off, size_t* len) { 219 if ((*data & 0x80000000) == 0) { 220 // 6.2: Generic Model 221 // 222 // EHT entry is a prel31 pointing to the PR, followed by data understood 223 // only by the personality routine. Fortunately, all existing assembler 224 // implementations, including GNU assembler, LLVM integrated assembler, 225 // and ARM assembler, assume that the unwind opcodes come after the 226 // personality rountine address. 227 *off = 1; // First byte is size data. 228 *len = (((data[1] >> 24) & 0xff) + 1) * 4; 229 data++; // Skip the first word, which is the prel31 offset. 230 } else { 231 // 6.3: ARM Compact Model 232 // 233 // EHT entries here correspond to the __aeabi_unwind_cpp_pr[012] PRs indeded 234 // by format: 235 Descriptor::Format format = 236 static_cast<Descriptor::Format>((*data & 0x0f000000) >> 24); 237 switch (format) { 238 case Descriptor::SU16: 239 *len = 4; 240 *off = 1; 241 break; 242 case Descriptor::LU16: 243 case Descriptor::LU32: 244 *len = 4 + 4 * ((*data & 0x00ff0000) >> 16); 245 *off = 2; 246 break; 247 default: 248 return nullptr; 249 } 250 } 251 return data; 252 } 253 254 _LIBUNWIND_EXPORT _Unwind_Reason_Code 255 _Unwind_VRS_Interpret(_Unwind_Context *context, const uint32_t *data, 256 size_t offset, size_t len) { 257 bool wrotePC = false; 258 bool finish = false; 259 while (offset < len && !finish) { 260 uint8_t byte = getByte(data, offset++); 261 if ((byte & 0x80) == 0) { 262 uint32_t sp; 263 _Unwind_VRS_Get(context, _UVRSC_CORE, UNW_ARM_SP, _UVRSD_UINT32, &sp); 264 if (byte & 0x40) 265 sp -= (((uint32_t)byte & 0x3f) << 2) + 4; 266 else 267 sp += ((uint32_t)byte << 2) + 4; 268 _Unwind_VRS_Set(context, _UVRSC_CORE, UNW_ARM_SP, _UVRSD_UINT32, &sp); 269 } else { 270 switch (byte & 0xf0) { 271 case 0x80: { 272 if (offset >= len) 273 return _URC_FAILURE; 274 uint32_t registers = 275 (((uint32_t)byte & 0x0f) << 12) | 276 (((uint32_t)getByte(data, offset++)) << 4); 277 if (!registers) 278 return _URC_FAILURE; 279 if (registers & (1 << 15)) 280 wrotePC = true; 281 _Unwind_VRS_Pop(context, _UVRSC_CORE, registers, _UVRSD_UINT32); 282 break; 283 } 284 case 0x90: { 285 uint8_t reg = byte & 0x0f; 286 if (reg == 13 || reg == 15) 287 return _URC_FAILURE; 288 uint32_t sp; 289 _Unwind_VRS_Get(context, _UVRSC_CORE, UNW_ARM_R0 + reg, 290 _UVRSD_UINT32, &sp); 291 _Unwind_VRS_Set(context, _UVRSC_CORE, UNW_ARM_SP, _UVRSD_UINT32, 292 &sp); 293 break; 294 } 295 case 0xa0: { 296 uint32_t registers = RegisterMask(4, byte & 0x07); 297 if (byte & 0x08) 298 registers |= 1 << 14; 299 _Unwind_VRS_Pop(context, _UVRSC_CORE, registers, _UVRSD_UINT32); 300 break; 301 } 302 case 0xb0: { 303 switch (byte) { 304 case 0xb0: 305 finish = true; 306 break; 307 case 0xb1: { 308 if (offset >= len) 309 return _URC_FAILURE; 310 uint8_t registers = getByte(data, offset++); 311 if (registers & 0xf0 || !registers) 312 return _URC_FAILURE; 313 _Unwind_VRS_Pop(context, _UVRSC_CORE, registers, _UVRSD_UINT32); 314 break; 315 } 316 case 0xb2: { 317 uint32_t addend = 0; 318 uint32_t shift = 0; 319 // This decodes a uleb128 value. 320 while (true) { 321 if (offset >= len) 322 return _URC_FAILURE; 323 uint32_t v = getByte(data, offset++); 324 addend |= (v & 0x7f) << shift; 325 if ((v & 0x80) == 0) 326 break; 327 shift += 7; 328 } 329 uint32_t sp; 330 _Unwind_VRS_Get(context, _UVRSC_CORE, UNW_ARM_SP, _UVRSD_UINT32, 331 &sp); 332 sp += 0x204 + (addend << 2); 333 _Unwind_VRS_Set(context, _UVRSC_CORE, UNW_ARM_SP, _UVRSD_UINT32, 334 &sp); 335 break; 336 } 337 case 0xb3: { 338 uint8_t v = getByte(data, offset++); 339 _Unwind_VRS_Pop(context, _UVRSC_VFP, 340 RegisterRange(static_cast<uint8_t>(v >> 4), 341 v & 0x0f), _UVRSD_VFPX); 342 break; 343 } 344 case 0xb4: 345 case 0xb5: 346 case 0xb6: 347 case 0xb7: 348 return _URC_FAILURE; 349 default: 350 _Unwind_VRS_Pop(context, _UVRSC_VFP, 351 RegisterRange(8, byte & 0x07), _UVRSD_VFPX); 352 break; 353 } 354 break; 355 } 356 case 0xc0: { 357 switch (byte) { 358 #if defined(__ARM_WMMX) 359 case 0xc0: 360 case 0xc1: 361 case 0xc2: 362 case 0xc3: 363 case 0xc4: 364 case 0xc5: 365 _Unwind_VRS_Pop(context, _UVRSC_WMMXD, 366 RegisterRange(10, byte & 0x7), _UVRSD_DOUBLE); 367 break; 368 case 0xc6: { 369 uint8_t v = getByte(data, offset++); 370 uint8_t start = static_cast<uint8_t>(v >> 4); 371 uint8_t count_minus_one = v & 0xf; 372 if (start + count_minus_one >= 16) 373 return _URC_FAILURE; 374 _Unwind_VRS_Pop(context, _UVRSC_WMMXD, 375 RegisterRange(start, count_minus_one), 376 _UVRSD_DOUBLE); 377 break; 378 } 379 case 0xc7: { 380 uint8_t v = getByte(data, offset++); 381 if (!v || v & 0xf0) 382 return _URC_FAILURE; 383 _Unwind_VRS_Pop(context, _UVRSC_WMMXC, v, _UVRSD_DOUBLE); 384 break; 385 } 386 #endif 387 case 0xc8: 388 case 0xc9: { 389 uint8_t v = getByte(data, offset++); 390 uint8_t start = 391 static_cast<uint8_t>(((byte == 0xc8) ? 16 : 0) + (v >> 4)); 392 uint8_t count_minus_one = v & 0xf; 393 if (start + count_minus_one >= 32) 394 return _URC_FAILURE; 395 _Unwind_VRS_Pop(context, _UVRSC_VFP, 396 RegisterRange(start, count_minus_one), 397 _UVRSD_DOUBLE); 398 break; 399 } 400 default: 401 return _URC_FAILURE; 402 } 403 break; 404 } 405 case 0xd0: { 406 if (byte & 0x08) 407 return _URC_FAILURE; 408 _Unwind_VRS_Pop(context, _UVRSC_VFP, RegisterRange(8, byte & 0x7), 409 _UVRSD_DOUBLE); 410 break; 411 } 412 default: 413 return _URC_FAILURE; 414 } 415 } 416 } 417 if (!wrotePC) { 418 uint32_t lr; 419 _Unwind_VRS_Get(context, _UVRSC_CORE, UNW_ARM_LR, _UVRSD_UINT32, &lr); 420 _Unwind_VRS_Set(context, _UVRSC_CORE, UNW_ARM_IP, _UVRSD_UINT32, &lr); 421 } 422 return _URC_CONTINUE_UNWIND; 423 } 424 425 extern "C" _LIBUNWIND_EXPORT _Unwind_Reason_Code 426 __aeabi_unwind_cpp_pr0(_Unwind_State state, _Unwind_Control_Block *ucbp, 427 _Unwind_Context *context) { 428 return unwindOneFrame(state, ucbp, context); 429 } 430 431 extern "C" _LIBUNWIND_EXPORT _Unwind_Reason_Code 432 __aeabi_unwind_cpp_pr1(_Unwind_State state, _Unwind_Control_Block *ucbp, 433 _Unwind_Context *context) { 434 return unwindOneFrame(state, ucbp, context); 435 } 436 437 extern "C" _LIBUNWIND_EXPORT _Unwind_Reason_Code 438 __aeabi_unwind_cpp_pr2(_Unwind_State state, _Unwind_Control_Block *ucbp, 439 _Unwind_Context *context) { 440 return unwindOneFrame(state, ucbp, context); 441 } 442 443 static _Unwind_Reason_Code 444 unwind_phase1(unw_context_t *uc, unw_cursor_t *cursor, _Unwind_Exception *exception_object) { 445 // EHABI #7.3 discusses preserving the VRS in a "temporary VRS" during 446 // phase 1 and then restoring it to the "primary VRS" for phase 2. The 447 // effect is phase 2 doesn't see any of the VRS manipulations from phase 1. 448 // In this implementation, the phases don't share the VRS backing store. 449 // Instead, they are passed the original |uc| and they create a new VRS 450 // from scratch thus achieving the same effect. 451 __unw_init_local(cursor, uc); 452 453 // Walk each frame looking for a place to stop. 454 for (bool handlerNotFound = true; handlerNotFound;) { 455 456 // See if frame has code to run (has personality routine). 457 unw_proc_info_t frameInfo; 458 if (__unw_get_proc_info(cursor, &frameInfo) != UNW_ESUCCESS) { 459 _LIBUNWIND_TRACE_UNWINDING( 460 "unwind_phase1(ex_ojb=%p): __unw_get_proc_info " 461 "failed => _URC_FATAL_PHASE1_ERROR", 462 static_cast<void *>(exception_object)); 463 return _URC_FATAL_PHASE1_ERROR; 464 } 465 466 // When tracing, print state information. 467 if (_LIBUNWIND_TRACING_UNWINDING) { 468 char functionBuf[512]; 469 const char *functionName = functionBuf; 470 unw_word_t offset; 471 if ((__unw_get_proc_name(cursor, functionBuf, sizeof(functionBuf), 472 &offset) != UNW_ESUCCESS) || 473 (frameInfo.start_ip + offset > frameInfo.end_ip)) 474 functionName = ".anonymous."; 475 unw_word_t pc; 476 __unw_get_reg(cursor, UNW_REG_IP, &pc); 477 _LIBUNWIND_TRACE_UNWINDING( 478 "unwind_phase1(ex_ojb=%p): pc=0x%" PRIxPTR ", start_ip=0x%" PRIxPTR ", func=%s, " 479 "lsda=0x%" PRIxPTR ", personality=0x%" PRIxPTR, 480 static_cast<void *>(exception_object), pc, 481 frameInfo.start_ip, functionName, 482 frameInfo.lsda, frameInfo.handler); 483 } 484 485 // If there is a personality routine, ask it if it will want to stop at 486 // this frame. 487 if (frameInfo.handler != 0) { 488 _Unwind_Personality_Fn p = 489 (_Unwind_Personality_Fn)(long)(frameInfo.handler); 490 _LIBUNWIND_TRACE_UNWINDING( 491 "unwind_phase1(ex_ojb=%p): calling personality function %p", 492 static_cast<void *>(exception_object), 493 reinterpret_cast<void *>(reinterpret_cast<uintptr_t>(p))); 494 struct _Unwind_Context *context = (struct _Unwind_Context *)(cursor); 495 exception_object->pr_cache.fnstart = frameInfo.start_ip; 496 exception_object->pr_cache.ehtp = 497 (_Unwind_EHT_Header *)frameInfo.unwind_info; 498 exception_object->pr_cache.additional = frameInfo.flags; 499 _Unwind_Reason_Code personalityResult = 500 (*p)(_US_VIRTUAL_UNWIND_FRAME, exception_object, context); 501 _LIBUNWIND_TRACE_UNWINDING( 502 "unwind_phase1(ex_ojb=%p): personality result %d start_ip %x ehtp %p " 503 "additional %x", 504 static_cast<void *>(exception_object), personalityResult, 505 exception_object->pr_cache.fnstart, 506 static_cast<void *>(exception_object->pr_cache.ehtp), 507 exception_object->pr_cache.additional); 508 switch (personalityResult) { 509 case _URC_HANDLER_FOUND: 510 // found a catch clause or locals that need destructing in this frame 511 // stop search and remember stack pointer at the frame 512 handlerNotFound = false; 513 // p should have initialized barrier_cache. EHABI #7.3.5 514 _LIBUNWIND_TRACE_UNWINDING( 515 "unwind_phase1(ex_ojb=%p): _URC_HANDLER_FOUND", 516 static_cast<void *>(exception_object)); 517 return _URC_NO_REASON; 518 519 case _URC_CONTINUE_UNWIND: 520 _LIBUNWIND_TRACE_UNWINDING( 521 "unwind_phase1(ex_ojb=%p): _URC_CONTINUE_UNWIND", 522 static_cast<void *>(exception_object)); 523 // continue unwinding 524 break; 525 526 // EHABI #7.3.3 527 case _URC_FAILURE: 528 return _URC_FAILURE; 529 530 default: 531 // something went wrong 532 _LIBUNWIND_TRACE_UNWINDING( 533 "unwind_phase1(ex_ojb=%p): _URC_FATAL_PHASE1_ERROR", 534 static_cast<void *>(exception_object)); 535 return _URC_FATAL_PHASE1_ERROR; 536 } 537 } 538 } 539 return _URC_NO_REASON; 540 } 541 542 static _Unwind_Reason_Code unwind_phase2(unw_context_t *uc, unw_cursor_t *cursor, 543 _Unwind_Exception *exception_object, 544 bool resume) { 545 // See comment at the start of unwind_phase1 regarding VRS integrity. 546 __unw_init_local(cursor, uc); 547 548 _LIBUNWIND_TRACE_UNWINDING("unwind_phase2(ex_ojb=%p)", 549 static_cast<void *>(exception_object)); 550 int frame_count = 0; 551 552 // Walk each frame until we reach where search phase said to stop. 553 while (true) { 554 // Ask libunwind to get next frame (skip over first which is 555 // _Unwind_RaiseException or _Unwind_Resume). 556 // 557 // Resume only ever makes sense for 1 frame. 558 _Unwind_State state = 559 resume ? _US_UNWIND_FRAME_RESUME : _US_UNWIND_FRAME_STARTING; 560 if (resume && frame_count == 1) { 561 // On a resume, first unwind the _Unwind_Resume() frame. The next frame 562 // is now the landing pad for the cleanup from a previous execution of 563 // phase2. To continue unwindingly correctly, replace VRS[15] with the 564 // IP of the frame that the previous run of phase2 installed the context 565 // for. After this, continue unwinding as if normal. 566 // 567 // See #7.4.6 for details. 568 __unw_set_reg(cursor, UNW_REG_IP, 569 exception_object->unwinder_cache.reserved2); 570 resume = false; 571 } 572 573 // Get info about this frame. 574 unw_word_t sp; 575 unw_proc_info_t frameInfo; 576 __unw_get_reg(cursor, UNW_REG_SP, &sp); 577 if (__unw_get_proc_info(cursor, &frameInfo) != UNW_ESUCCESS) { 578 _LIBUNWIND_TRACE_UNWINDING( 579 "unwind_phase2(ex_ojb=%p): __unw_get_proc_info " 580 "failed => _URC_FATAL_PHASE2_ERROR", 581 static_cast<void *>(exception_object)); 582 return _URC_FATAL_PHASE2_ERROR; 583 } 584 585 // When tracing, print state information. 586 if (_LIBUNWIND_TRACING_UNWINDING) { 587 char functionBuf[512]; 588 const char *functionName = functionBuf; 589 unw_word_t offset; 590 if ((__unw_get_proc_name(cursor, functionBuf, sizeof(functionBuf), 591 &offset) != UNW_ESUCCESS) || 592 (frameInfo.start_ip + offset > frameInfo.end_ip)) 593 functionName = ".anonymous."; 594 _LIBUNWIND_TRACE_UNWINDING( 595 "unwind_phase2(ex_ojb=%p): start_ip=0x%" PRIxPTR ", func=%s, sp=0x%" PRIxPTR ", " 596 "lsda=0x%" PRIxPTR ", personality=0x%" PRIxPTR "", 597 static_cast<void *>(exception_object), frameInfo.start_ip, 598 functionName, sp, frameInfo.lsda, 599 frameInfo.handler); 600 } 601 602 // If there is a personality routine, tell it we are unwinding. 603 if (frameInfo.handler != 0) { 604 _Unwind_Personality_Fn p = 605 (_Unwind_Personality_Fn)(long)(frameInfo.handler); 606 struct _Unwind_Context *context = (struct _Unwind_Context *)(cursor); 607 // EHABI #7.2 608 exception_object->pr_cache.fnstart = frameInfo.start_ip; 609 exception_object->pr_cache.ehtp = 610 (_Unwind_EHT_Header *)frameInfo.unwind_info; 611 exception_object->pr_cache.additional = frameInfo.flags; 612 _Unwind_Reason_Code personalityResult = 613 (*p)(state, exception_object, context); 614 switch (personalityResult) { 615 case _URC_CONTINUE_UNWIND: 616 // Continue unwinding 617 _LIBUNWIND_TRACE_UNWINDING( 618 "unwind_phase2(ex_ojb=%p): _URC_CONTINUE_UNWIND", 619 static_cast<void *>(exception_object)); 620 // EHABI #7.2 621 if (sp == exception_object->barrier_cache.sp) { 622 // Phase 1 said we would stop at this frame, but we did not... 623 _LIBUNWIND_ABORT("during phase1 personality function said it would " 624 "stop here, but now in phase2 it did not stop here"); 625 } 626 break; 627 case _URC_INSTALL_CONTEXT: 628 _LIBUNWIND_TRACE_UNWINDING( 629 "unwind_phase2(ex_ojb=%p): _URC_INSTALL_CONTEXT", 630 static_cast<void *>(exception_object)); 631 // Personality routine says to transfer control to landing pad. 632 // We may get control back if landing pad calls _Unwind_Resume(). 633 if (_LIBUNWIND_TRACING_UNWINDING) { 634 unw_word_t pc; 635 __unw_get_reg(cursor, UNW_REG_IP, &pc); 636 __unw_get_reg(cursor, UNW_REG_SP, &sp); 637 _LIBUNWIND_TRACE_UNWINDING("unwind_phase2(ex_ojb=%p): re-entering " 638 "user code with ip=0x%" PRIxPTR ", sp=0x%" PRIxPTR, 639 static_cast<void *>(exception_object), 640 pc, sp); 641 } 642 643 { 644 // EHABI #7.4.1 says we need to preserve pc for when _Unwind_Resume 645 // is called back, to find this same frame. 646 unw_word_t pc; 647 __unw_get_reg(cursor, UNW_REG_IP, &pc); 648 exception_object->unwinder_cache.reserved2 = (uint32_t)pc; 649 } 650 __unw_resume(cursor); 651 // __unw_resume() only returns if there was an error. 652 return _URC_FATAL_PHASE2_ERROR; 653 654 // # EHABI #7.4.3 655 case _URC_FAILURE: 656 abort(); 657 658 default: 659 // Personality routine returned an unknown result code. 660 _LIBUNWIND_DEBUG_LOG("personality function returned unknown result %d", 661 personalityResult); 662 return _URC_FATAL_PHASE2_ERROR; 663 } 664 } 665 frame_count++; 666 } 667 668 // Clean up phase did not resume at the frame that the search phase 669 // said it would... 670 return _URC_FATAL_PHASE2_ERROR; 671 } 672 673 /// Called by __cxa_throw. Only returns if there is a fatal error. 674 _LIBUNWIND_EXPORT _Unwind_Reason_Code 675 _Unwind_RaiseException(_Unwind_Exception *exception_object) { 676 _LIBUNWIND_TRACE_API("_Unwind_RaiseException(ex_obj=%p)", 677 static_cast<void *>(exception_object)); 678 unw_context_t uc; 679 unw_cursor_t cursor; 680 __unw_getcontext(&uc); 681 682 // This field for is for compatibility with GCC to say this isn't a forced 683 // unwind. EHABI #7.2 684 exception_object->unwinder_cache.reserved1 = 0; 685 686 // phase 1: the search phase 687 _Unwind_Reason_Code phase1 = unwind_phase1(&uc, &cursor, exception_object); 688 if (phase1 != _URC_NO_REASON) 689 return phase1; 690 691 // phase 2: the clean up phase 692 return unwind_phase2(&uc, &cursor, exception_object, false); 693 } 694 695 _LIBUNWIND_EXPORT void _Unwind_Complete(_Unwind_Exception* exception_object) { 696 // This is to be called when exception handling completes to give us a chance 697 // to perform any housekeeping. EHABI #7.2. But we have nothing to do here. 698 (void)exception_object; 699 } 700 701 /// When _Unwind_RaiseException() is in phase2, it hands control 702 /// to the personality function at each frame. The personality 703 /// may force a jump to a landing pad in that function, the landing 704 /// pad code may then call _Unwind_Resume() to continue with the 705 /// unwinding. Note: the call to _Unwind_Resume() is from compiler 706 /// geneated user code. All other _Unwind_* routines are called 707 /// by the C++ runtime __cxa_* routines. 708 /// 709 /// Note: re-throwing an exception (as opposed to continuing the unwind) 710 /// is implemented by having the code call __cxa_rethrow() which 711 /// in turn calls _Unwind_Resume_or_Rethrow(). 712 _LIBUNWIND_EXPORT void 713 _Unwind_Resume(_Unwind_Exception *exception_object) { 714 _LIBUNWIND_TRACE_API("_Unwind_Resume(ex_obj=%p)", 715 static_cast<void *>(exception_object)); 716 unw_context_t uc; 717 unw_cursor_t cursor; 718 __unw_getcontext(&uc); 719 720 // _Unwind_RaiseException on EHABI will always set the reserved1 field to 0, 721 // which is in the same position as private_1 below. 722 // TODO(ajwong): Who wronte the above? Why is it true? 723 unwind_phase2(&uc, &cursor, exception_object, true); 724 725 // Clients assume _Unwind_Resume() does not return, so all we can do is abort. 726 _LIBUNWIND_ABORT("_Unwind_Resume() can't return"); 727 } 728 729 /// Called by personality handler during phase 2 to get LSDA for current frame. 730 _LIBUNWIND_EXPORT uintptr_t 731 _Unwind_GetLanguageSpecificData(struct _Unwind_Context *context) { 732 unw_cursor_t *cursor = (unw_cursor_t *)context; 733 unw_proc_info_t frameInfo; 734 uintptr_t result = 0; 735 if (__unw_get_proc_info(cursor, &frameInfo) == UNW_ESUCCESS) 736 result = (uintptr_t)frameInfo.lsda; 737 _LIBUNWIND_TRACE_API( 738 "_Unwind_GetLanguageSpecificData(context=%p) => 0x%llx", 739 static_cast<void *>(context), (long long)result); 740 return result; 741 } 742 743 static uint64_t ValueAsBitPattern(_Unwind_VRS_DataRepresentation representation, 744 void* valuep) { 745 uint64_t value = 0; 746 switch (representation) { 747 case _UVRSD_UINT32: 748 case _UVRSD_FLOAT: 749 memcpy(&value, valuep, sizeof(uint32_t)); 750 break; 751 752 case _UVRSD_VFPX: 753 case _UVRSD_UINT64: 754 case _UVRSD_DOUBLE: 755 memcpy(&value, valuep, sizeof(uint64_t)); 756 break; 757 } 758 return value; 759 } 760 761 _LIBUNWIND_EXPORT _Unwind_VRS_Result 762 _Unwind_VRS_Set(_Unwind_Context *context, _Unwind_VRS_RegClass regclass, 763 uint32_t regno, _Unwind_VRS_DataRepresentation representation, 764 void *valuep) { 765 _LIBUNWIND_TRACE_API("_Unwind_VRS_Set(context=%p, regclass=%d, reg=%d, " 766 "rep=%d, value=0x%llX)", 767 static_cast<void *>(context), regclass, regno, 768 representation, 769 ValueAsBitPattern(representation, valuep)); 770 unw_cursor_t *cursor = (unw_cursor_t *)context; 771 switch (regclass) { 772 case _UVRSC_CORE: 773 if (representation != _UVRSD_UINT32 || regno > 15) 774 return _UVRSR_FAILED; 775 return __unw_set_reg(cursor, (unw_regnum_t)(UNW_ARM_R0 + regno), 776 *(unw_word_t *)valuep) == UNW_ESUCCESS 777 ? _UVRSR_OK 778 : _UVRSR_FAILED; 779 case _UVRSC_VFP: 780 if (representation != _UVRSD_VFPX && representation != _UVRSD_DOUBLE) 781 return _UVRSR_FAILED; 782 if (representation == _UVRSD_VFPX) { 783 // Can only touch d0-15 with FSTMFDX. 784 if (regno > 15) 785 return _UVRSR_FAILED; 786 __unw_save_vfp_as_X(cursor); 787 } else { 788 if (regno > 31) 789 return _UVRSR_FAILED; 790 } 791 return __unw_set_fpreg(cursor, (unw_regnum_t)(UNW_ARM_D0 + regno), 792 *(unw_fpreg_t *)valuep) == UNW_ESUCCESS 793 ? _UVRSR_OK 794 : _UVRSR_FAILED; 795 #if defined(__ARM_WMMX) 796 case _UVRSC_WMMXC: 797 if (representation != _UVRSD_UINT32 || regno > 3) 798 return _UVRSR_FAILED; 799 return __unw_set_reg(cursor, (unw_regnum_t)(UNW_ARM_WC0 + regno), 800 *(unw_word_t *)valuep) == UNW_ESUCCESS 801 ? _UVRSR_OK 802 : _UVRSR_FAILED; 803 case _UVRSC_WMMXD: 804 if (representation != _UVRSD_DOUBLE || regno > 31) 805 return _UVRSR_FAILED; 806 return __unw_set_fpreg(cursor, (unw_regnum_t)(UNW_ARM_WR0 + regno), 807 *(unw_fpreg_t *)valuep) == UNW_ESUCCESS 808 ? _UVRSR_OK 809 : _UVRSR_FAILED; 810 #else 811 case _UVRSC_WMMXC: 812 case _UVRSC_WMMXD: 813 break; 814 #endif 815 } 816 _LIBUNWIND_ABORT("unsupported register class"); 817 } 818 819 static _Unwind_VRS_Result 820 _Unwind_VRS_Get_Internal(_Unwind_Context *context, 821 _Unwind_VRS_RegClass regclass, uint32_t regno, 822 _Unwind_VRS_DataRepresentation representation, 823 void *valuep) { 824 unw_cursor_t *cursor = (unw_cursor_t *)context; 825 switch (regclass) { 826 case _UVRSC_CORE: 827 if (representation != _UVRSD_UINT32 || regno > 15) 828 return _UVRSR_FAILED; 829 return __unw_get_reg(cursor, (unw_regnum_t)(UNW_ARM_R0 + regno), 830 (unw_word_t *)valuep) == UNW_ESUCCESS 831 ? _UVRSR_OK 832 : _UVRSR_FAILED; 833 case _UVRSC_VFP: 834 if (representation != _UVRSD_VFPX && representation != _UVRSD_DOUBLE) 835 return _UVRSR_FAILED; 836 if (representation == _UVRSD_VFPX) { 837 // Can only touch d0-15 with FSTMFDX. 838 if (regno > 15) 839 return _UVRSR_FAILED; 840 __unw_save_vfp_as_X(cursor); 841 } else { 842 if (regno > 31) 843 return _UVRSR_FAILED; 844 } 845 return __unw_get_fpreg(cursor, (unw_regnum_t)(UNW_ARM_D0 + regno), 846 (unw_fpreg_t *)valuep) == UNW_ESUCCESS 847 ? _UVRSR_OK 848 : _UVRSR_FAILED; 849 #if defined(__ARM_WMMX) 850 case _UVRSC_WMMXC: 851 if (representation != _UVRSD_UINT32 || regno > 3) 852 return _UVRSR_FAILED; 853 return __unw_get_reg(cursor, (unw_regnum_t)(UNW_ARM_WC0 + regno), 854 (unw_word_t *)valuep) == UNW_ESUCCESS 855 ? _UVRSR_OK 856 : _UVRSR_FAILED; 857 case _UVRSC_WMMXD: 858 if (representation != _UVRSD_DOUBLE || regno > 31) 859 return _UVRSR_FAILED; 860 return __unw_get_fpreg(cursor, (unw_regnum_t)(UNW_ARM_WR0 + regno), 861 (unw_fpreg_t *)valuep) == UNW_ESUCCESS 862 ? _UVRSR_OK 863 : _UVRSR_FAILED; 864 #else 865 case _UVRSC_WMMXC: 866 case _UVRSC_WMMXD: 867 break; 868 #endif 869 } 870 _LIBUNWIND_ABORT("unsupported register class"); 871 } 872 873 _LIBUNWIND_EXPORT _Unwind_VRS_Result 874 _Unwind_VRS_Get(_Unwind_Context *context, _Unwind_VRS_RegClass regclass, 875 uint32_t regno, _Unwind_VRS_DataRepresentation representation, 876 void *valuep) { 877 _Unwind_VRS_Result result = 878 _Unwind_VRS_Get_Internal(context, regclass, regno, representation, 879 valuep); 880 _LIBUNWIND_TRACE_API("_Unwind_VRS_Get(context=%p, regclass=%d, reg=%d, " 881 "rep=%d, value=0x%llX, result = %d)", 882 static_cast<void *>(context), regclass, regno, 883 representation, 884 ValueAsBitPattern(representation, valuep), result); 885 return result; 886 } 887 888 _Unwind_VRS_Result 889 _Unwind_VRS_Pop(_Unwind_Context *context, _Unwind_VRS_RegClass regclass, 890 uint32_t discriminator, 891 _Unwind_VRS_DataRepresentation representation) { 892 _LIBUNWIND_TRACE_API("_Unwind_VRS_Pop(context=%p, regclass=%d, " 893 "discriminator=%d, representation=%d)", 894 static_cast<void *>(context), regclass, discriminator, 895 representation); 896 switch (regclass) { 897 case _UVRSC_WMMXC: 898 #if !defined(__ARM_WMMX) 899 break; 900 #endif 901 case _UVRSC_CORE: { 902 if (representation != _UVRSD_UINT32) 903 return _UVRSR_FAILED; 904 // When popping SP from the stack, we don't want to override it from the 905 // computed new stack location. See EHABI #7.5.4 table 3. 906 bool poppedSP = false; 907 uint32_t* sp; 908 if (_Unwind_VRS_Get(context, _UVRSC_CORE, UNW_ARM_SP, 909 _UVRSD_UINT32, &sp) != _UVRSR_OK) { 910 return _UVRSR_FAILED; 911 } 912 for (uint32_t i = 0; i < 16; ++i) { 913 if (!(discriminator & static_cast<uint32_t>(1 << i))) 914 continue; 915 uint32_t value = *sp++; 916 if (regclass == _UVRSC_CORE && i == 13) 917 poppedSP = true; 918 if (_Unwind_VRS_Set(context, regclass, i, 919 _UVRSD_UINT32, &value) != _UVRSR_OK) { 920 return _UVRSR_FAILED; 921 } 922 } 923 if (!poppedSP) { 924 return _Unwind_VRS_Set(context, _UVRSC_CORE, UNW_ARM_SP, 925 _UVRSD_UINT32, &sp); 926 } 927 return _UVRSR_OK; 928 } 929 case _UVRSC_WMMXD: 930 #if !defined(__ARM_WMMX) 931 break; 932 #endif 933 case _UVRSC_VFP: { 934 if (representation != _UVRSD_VFPX && representation != _UVRSD_DOUBLE) 935 return _UVRSR_FAILED; 936 uint32_t first = discriminator >> 16; 937 uint32_t count = discriminator & 0xffff; 938 uint32_t end = first+count; 939 uint32_t* sp; 940 if (_Unwind_VRS_Get(context, _UVRSC_CORE, UNW_ARM_SP, 941 _UVRSD_UINT32, &sp) != _UVRSR_OK) { 942 return _UVRSR_FAILED; 943 } 944 // For _UVRSD_VFPX, we're assuming the data is stored in FSTMX "standard 945 // format 1", which is equivalent to FSTMD + a padding word. 946 for (uint32_t i = first; i < end; ++i) { 947 // SP is only 32-bit aligned so don't copy 64-bit at a time. 948 uint64_t w0 = *sp++; 949 uint64_t w1 = *sp++; 950 #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ 951 uint64_t value = (w1 << 32) | w0; 952 #elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__ 953 uint64_t value = (w0 << 32) | w1; 954 #else 955 #error "Unable to determine endianess" 956 #endif 957 if (_Unwind_VRS_Set(context, regclass, i, representation, &value) != 958 _UVRSR_OK) 959 return _UVRSR_FAILED; 960 } 961 if (representation == _UVRSD_VFPX) 962 ++sp; 963 return _Unwind_VRS_Set(context, _UVRSC_CORE, UNW_ARM_SP, _UVRSD_UINT32, 964 &sp); 965 } 966 } 967 _LIBUNWIND_ABORT("unsupported register class"); 968 } 969 970 /// Called by personality handler during phase 2 to find the start of the 971 /// function. 972 _LIBUNWIND_EXPORT uintptr_t 973 _Unwind_GetRegionStart(struct _Unwind_Context *context) { 974 unw_cursor_t *cursor = (unw_cursor_t *)context; 975 unw_proc_info_t frameInfo; 976 uintptr_t result = 0; 977 if (__unw_get_proc_info(cursor, &frameInfo) == UNW_ESUCCESS) 978 result = (uintptr_t)frameInfo.start_ip; 979 _LIBUNWIND_TRACE_API("_Unwind_GetRegionStart(context=%p) => 0x%llX", 980 static_cast<void *>(context), (long long)result); 981 return result; 982 } 983 984 985 /// Called by personality handler during phase 2 if a foreign exception 986 // is caught. 987 _LIBUNWIND_EXPORT void 988 _Unwind_DeleteException(_Unwind_Exception *exception_object) { 989 _LIBUNWIND_TRACE_API("_Unwind_DeleteException(ex_obj=%p)", 990 static_cast<void *>(exception_object)); 991 if (exception_object->exception_cleanup != NULL) 992 (*exception_object->exception_cleanup)(_URC_FOREIGN_EXCEPTION_CAUGHT, 993 exception_object); 994 } 995 996 extern "C" _LIBUNWIND_EXPORT _Unwind_Reason_Code 997 __gnu_unwind_frame(_Unwind_Exception *exception_object, 998 struct _Unwind_Context *context) { 999 unw_cursor_t *cursor = (unw_cursor_t *)context; 1000 if (__unw_step(cursor) != UNW_STEP_SUCCESS) 1001 return _URC_FAILURE; 1002 return _URC_OK; 1003 } 1004 1005 #endif // defined(_LIBUNWIND_ARM_EHABI) 1006