1 //===-- DWARFCallFrameInfo.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 9 #include "lldb/Symbol/DWARFCallFrameInfo.h" 10 #include "lldb/Core/Debugger.h" 11 #include "lldb/Core/Module.h" 12 #include "lldb/Core/Section.h" 13 #include "lldb/Core/dwarf.h" 14 #include "lldb/Host/Host.h" 15 #include "lldb/Symbol/ObjectFile.h" 16 #include "lldb/Symbol/UnwindPlan.h" 17 #include "lldb/Target/RegisterContext.h" 18 #include "lldb/Target/Thread.h" 19 #include "lldb/Utility/ArchSpec.h" 20 #include "lldb/Utility/LLDBLog.h" 21 #include "lldb/Utility/Log.h" 22 #include "lldb/Utility/Timer.h" 23 #include <cstring> 24 #include <list> 25 #include <optional> 26 27 using namespace lldb; 28 using namespace lldb_private; 29 using namespace lldb_private::dwarf; 30 31 // GetDwarfEHPtr 32 // 33 // Used for calls when the value type is specified by a DWARF EH Frame pointer 34 // encoding. 35 static uint64_t 36 GetGNUEHPointer(const DataExtractor &DE, lldb::offset_t *offset_ptr, 37 uint32_t eh_ptr_enc, addr_t pc_rel_addr, addr_t text_addr, 38 addr_t data_addr) //, BSDRelocs *data_relocs) const 39 { 40 if (eh_ptr_enc == DW_EH_PE_omit) 41 return ULLONG_MAX; // Value isn't in the buffer... 42 43 uint64_t baseAddress = 0; 44 uint64_t addressValue = 0; 45 const uint32_t addr_size = DE.GetAddressByteSize(); 46 assert(addr_size == 4 || addr_size == 8); 47 48 bool signExtendValue = false; 49 // Decode the base part or adjust our offset 50 switch (eh_ptr_enc & 0x70) { 51 case DW_EH_PE_pcrel: 52 signExtendValue = true; 53 baseAddress = *offset_ptr; 54 if (pc_rel_addr != LLDB_INVALID_ADDRESS) 55 baseAddress += pc_rel_addr; 56 // else 57 // Log::GlobalWarning ("PC relative pointer encoding found with 58 // invalid pc relative address."); 59 break; 60 61 case DW_EH_PE_textrel: 62 signExtendValue = true; 63 if (text_addr != LLDB_INVALID_ADDRESS) 64 baseAddress = text_addr; 65 // else 66 // Log::GlobalWarning ("text relative pointer encoding being 67 // decoded with invalid text section address, setting base address 68 // to zero."); 69 break; 70 71 case DW_EH_PE_datarel: 72 signExtendValue = true; 73 if (data_addr != LLDB_INVALID_ADDRESS) 74 baseAddress = data_addr; 75 // else 76 // Log::GlobalWarning ("data relative pointer encoding being 77 // decoded with invalid data section address, setting base address 78 // to zero."); 79 break; 80 81 case DW_EH_PE_funcrel: 82 signExtendValue = true; 83 break; 84 85 case DW_EH_PE_aligned: { 86 // SetPointerSize should be called prior to extracting these so the pointer 87 // size is cached 88 assert(addr_size != 0); 89 if (addr_size) { 90 // Align to a address size boundary first 91 uint32_t alignOffset = *offset_ptr % addr_size; 92 if (alignOffset) 93 offset_ptr += addr_size - alignOffset; 94 } 95 } break; 96 97 default: 98 break; 99 } 100 101 // Decode the value part 102 switch (eh_ptr_enc & DW_EH_PE_MASK_ENCODING) { 103 case DW_EH_PE_absptr: { 104 addressValue = DE.GetAddress(offset_ptr); 105 // if (data_relocs) 106 // addressValue = data_relocs->Relocate(*offset_ptr - 107 // addr_size, *this, addressValue); 108 } break; 109 case DW_EH_PE_uleb128: 110 addressValue = DE.GetULEB128(offset_ptr); 111 break; 112 case DW_EH_PE_udata2: 113 addressValue = DE.GetU16(offset_ptr); 114 break; 115 case DW_EH_PE_udata4: 116 addressValue = DE.GetU32(offset_ptr); 117 break; 118 case DW_EH_PE_udata8: 119 addressValue = DE.GetU64(offset_ptr); 120 break; 121 case DW_EH_PE_sleb128: 122 addressValue = DE.GetSLEB128(offset_ptr); 123 break; 124 case DW_EH_PE_sdata2: 125 addressValue = (int16_t)DE.GetU16(offset_ptr); 126 break; 127 case DW_EH_PE_sdata4: 128 addressValue = (int32_t)DE.GetU32(offset_ptr); 129 break; 130 case DW_EH_PE_sdata8: 131 addressValue = (int64_t)DE.GetU64(offset_ptr); 132 break; 133 default: 134 // Unhandled encoding type 135 assert(eh_ptr_enc); 136 break; 137 } 138 139 // Since we promote everything to 64 bit, we may need to sign extend 140 if (signExtendValue && addr_size < sizeof(baseAddress)) { 141 uint64_t sign_bit = 1ull << ((addr_size * 8ull) - 1ull); 142 if (sign_bit & addressValue) { 143 uint64_t mask = ~sign_bit + 1; 144 addressValue |= mask; 145 } 146 } 147 return baseAddress + addressValue; 148 } 149 150 DWARFCallFrameInfo::DWARFCallFrameInfo(ObjectFile &objfile, 151 SectionSP §ion_sp, Type type) 152 : m_objfile(objfile), m_section_sp(section_sp), m_type(type) {} 153 154 bool DWARFCallFrameInfo::GetUnwindPlan(const Address &addr, 155 UnwindPlan &unwind_plan) { 156 return GetUnwindPlan(AddressRange(addr, 1), unwind_plan); 157 } 158 159 bool DWARFCallFrameInfo::GetUnwindPlan(const AddressRange &range, 160 UnwindPlan &unwind_plan) { 161 FDEEntryMap::Entry fde_entry; 162 Address addr = range.GetBaseAddress(); 163 164 // Make sure that the Address we're searching for is the same object file as 165 // this DWARFCallFrameInfo, we only store File offsets in m_fde_index. 166 ModuleSP module_sp = addr.GetModule(); 167 if (module_sp.get() == nullptr || module_sp->GetObjectFile() == nullptr || 168 module_sp->GetObjectFile() != &m_objfile) 169 return false; 170 171 if (std::optional<FDEEntryMap::Entry> entry = GetFirstFDEEntryInRange(range)) 172 return FDEToUnwindPlan(entry->data, addr, unwind_plan); 173 return false; 174 } 175 176 bool DWARFCallFrameInfo::GetAddressRange(Address addr, AddressRange &range) { 177 178 // Make sure that the Address we're searching for is the same object file as 179 // this DWARFCallFrameInfo, we only store File offsets in m_fde_index. 180 ModuleSP module_sp = addr.GetModule(); 181 if (module_sp.get() == nullptr || module_sp->GetObjectFile() == nullptr || 182 module_sp->GetObjectFile() != &m_objfile) 183 return false; 184 185 if (m_section_sp.get() == nullptr || m_section_sp->IsEncrypted()) 186 return false; 187 GetFDEIndex(); 188 FDEEntryMap::Entry *fde_entry = 189 m_fde_index.FindEntryThatContains(addr.GetFileAddress()); 190 if (!fde_entry) 191 return false; 192 193 range = AddressRange(fde_entry->base, fde_entry->size, 194 m_objfile.GetSectionList()); 195 return true; 196 } 197 198 std::optional<DWARFCallFrameInfo::FDEEntryMap::Entry> 199 DWARFCallFrameInfo::GetFirstFDEEntryInRange(const AddressRange &range) { 200 if (!m_section_sp || m_section_sp->IsEncrypted()) 201 return std::nullopt; 202 203 GetFDEIndex(); 204 205 addr_t start_file_addr = range.GetBaseAddress().GetFileAddress(); 206 const FDEEntryMap::Entry *fde = 207 m_fde_index.FindEntryThatContainsOrFollows(start_file_addr); 208 if (fde && fde->DoesIntersect( 209 FDEEntryMap::Range(start_file_addr, range.GetByteSize()))) 210 return *fde; 211 212 return std::nullopt; 213 } 214 215 void DWARFCallFrameInfo::GetFunctionAddressAndSizeVector( 216 FunctionAddressAndSizeVector &function_info) { 217 GetFDEIndex(); 218 const size_t count = m_fde_index.GetSize(); 219 function_info.Clear(); 220 if (count > 0) 221 function_info.Reserve(count); 222 for (size_t i = 0; i < count; ++i) { 223 const FDEEntryMap::Entry *func_offset_data_entry = 224 m_fde_index.GetEntryAtIndex(i); 225 if (func_offset_data_entry) { 226 FunctionAddressAndSizeVector::Entry function_offset_entry( 227 func_offset_data_entry->base, func_offset_data_entry->size); 228 function_info.Append(function_offset_entry); 229 } 230 } 231 } 232 233 const DWARFCallFrameInfo::CIE * 234 DWARFCallFrameInfo::GetCIE(dw_offset_t cie_offset) { 235 cie_map_t::iterator pos = m_cie_map.find(cie_offset); 236 237 if (pos != m_cie_map.end()) { 238 // Parse and cache the CIE 239 if (pos->second == nullptr) 240 pos->second = ParseCIE(cie_offset); 241 242 return pos->second.get(); 243 } 244 return nullptr; 245 } 246 247 DWARFCallFrameInfo::CIESP 248 DWARFCallFrameInfo::ParseCIE(const dw_offset_t cie_offset) { 249 CIESP cie_sp(new CIE(cie_offset)); 250 lldb::offset_t offset = cie_offset; 251 if (!m_cfi_data_initialized) 252 GetCFIData(); 253 uint32_t length = m_cfi_data.GetU32(&offset); 254 dw_offset_t cie_id, end_offset; 255 bool is_64bit = (length == UINT32_MAX); 256 if (is_64bit) { 257 length = m_cfi_data.GetU64(&offset); 258 cie_id = m_cfi_data.GetU64(&offset); 259 end_offset = cie_offset + length + 12; 260 } else { 261 cie_id = m_cfi_data.GetU32(&offset); 262 end_offset = cie_offset + length + 4; 263 } 264 if (length > 0 && ((m_type == DWARF && cie_id == UINT32_MAX) || 265 (m_type == EH && cie_id == 0ul))) { 266 size_t i; 267 // cie.offset = cie_offset; 268 // cie.length = length; 269 // cie.cieID = cieID; 270 cie_sp->ptr_encoding = DW_EH_PE_absptr; // default 271 cie_sp->version = m_cfi_data.GetU8(&offset); 272 if (cie_sp->version > CFI_VERSION4) { 273 Debugger::ReportError( 274 llvm::formatv("CIE parse error: CFI version {0} is not supported", 275 cie_sp->version)); 276 return nullptr; 277 } 278 279 for (i = 0; i < CFI_AUG_MAX_SIZE; ++i) { 280 cie_sp->augmentation[i] = m_cfi_data.GetU8(&offset); 281 if (cie_sp->augmentation[i] == '\0') { 282 // Zero out remaining bytes in augmentation string 283 for (size_t j = i + 1; j < CFI_AUG_MAX_SIZE; ++j) 284 cie_sp->augmentation[j] = '\0'; 285 286 break; 287 } 288 } 289 290 if (i == CFI_AUG_MAX_SIZE && 291 cie_sp->augmentation[CFI_AUG_MAX_SIZE - 1] != '\0') { 292 Debugger::ReportError(llvm::formatv( 293 "CIE parse error: CIE augmentation string was too large " 294 "for the fixed sized buffer of {0} bytes.", 295 CFI_AUG_MAX_SIZE)); 296 return nullptr; 297 } 298 299 // m_cfi_data uses address size from target architecture of the process may 300 // ignore these fields? 301 if (m_type == DWARF && cie_sp->version >= CFI_VERSION4) { 302 cie_sp->address_size = m_cfi_data.GetU8(&offset); 303 cie_sp->segment_size = m_cfi_data.GetU8(&offset); 304 } 305 306 cie_sp->code_align = (uint32_t)m_cfi_data.GetULEB128(&offset); 307 cie_sp->data_align = (int32_t)m_cfi_data.GetSLEB128(&offset); 308 309 cie_sp->return_addr_reg_num = 310 m_type == DWARF && cie_sp->version >= CFI_VERSION3 311 ? static_cast<uint32_t>(m_cfi_data.GetULEB128(&offset)) 312 : m_cfi_data.GetU8(&offset); 313 314 if (cie_sp->augmentation[0]) { 315 // Get the length of the eh_frame augmentation data which starts with a 316 // ULEB128 length in bytes 317 const size_t aug_data_len = (size_t)m_cfi_data.GetULEB128(&offset); 318 const size_t aug_data_end = offset + aug_data_len; 319 const size_t aug_str_len = strlen(cie_sp->augmentation); 320 // A 'z' may be present as the first character of the string. 321 // If present, the Augmentation Data field shall be present. The contents 322 // of the Augmentation Data shall be interpreted according to other 323 // characters in the Augmentation String. 324 if (cie_sp->augmentation[0] == 'z') { 325 // Extract the Augmentation Data 326 size_t aug_str_idx = 0; 327 for (aug_str_idx = 1; aug_str_idx < aug_str_len; aug_str_idx++) { 328 char aug = cie_sp->augmentation[aug_str_idx]; 329 switch (aug) { 330 case 'L': 331 // Indicates the presence of one argument in the Augmentation Data 332 // of the CIE, and a corresponding argument in the Augmentation 333 // Data of the FDE. The argument in the Augmentation Data of the 334 // CIE is 1-byte and represents the pointer encoding used for the 335 // argument in the Augmentation Data of the FDE, which is the 336 // address of a language-specific data area (LSDA). The size of the 337 // LSDA pointer is specified by the pointer encoding used. 338 cie_sp->lsda_addr_encoding = m_cfi_data.GetU8(&offset); 339 break; 340 341 case 'P': 342 // Indicates the presence of two arguments in the Augmentation Data 343 // of the CIE. The first argument is 1-byte and represents the 344 // pointer encoding used for the second argument, which is the 345 // address of a personality routine handler. The size of the 346 // personality routine pointer is specified by the pointer encoding 347 // used. 348 // 349 // The address of the personality function will be stored at this 350 // location. Pre-execution, it will be all zero's so don't read it 351 // until we're trying to do an unwind & the reloc has been 352 // resolved. 353 { 354 uint8_t arg_ptr_encoding = m_cfi_data.GetU8(&offset); 355 const lldb::addr_t pc_rel_addr = m_section_sp->GetFileAddress(); 356 cie_sp->personality_loc = GetGNUEHPointer( 357 m_cfi_data, &offset, arg_ptr_encoding, pc_rel_addr, 358 LLDB_INVALID_ADDRESS, LLDB_INVALID_ADDRESS); 359 } 360 break; 361 362 case 'R': 363 // A 'R' may be present at any position after the 364 // first character of the string. The Augmentation Data shall 365 // include a 1 byte argument that represents the pointer encoding 366 // for the address pointers used in the FDE. Example: 0x1B == 367 // DW_EH_PE_pcrel | DW_EH_PE_sdata4 368 cie_sp->ptr_encoding = m_cfi_data.GetU8(&offset); 369 break; 370 } 371 } 372 } else if (strcmp(cie_sp->augmentation, "eh") == 0) { 373 // If the Augmentation string has the value "eh", then the EH Data 374 // field shall be present 375 } 376 377 // Set the offset to be the end of the augmentation data just in case we 378 // didn't understand any of the data. 379 offset = (uint32_t)aug_data_end; 380 } 381 382 if (end_offset > offset) { 383 cie_sp->inst_offset = offset; 384 cie_sp->inst_length = end_offset - offset; 385 } 386 while (offset < end_offset) { 387 uint8_t inst = m_cfi_data.GetU8(&offset); 388 uint8_t primary_opcode = inst & 0xC0; 389 uint8_t extended_opcode = inst & 0x3F; 390 391 if (!HandleCommonDwarfOpcode(primary_opcode, extended_opcode, 392 cie_sp->data_align, offset, 393 cie_sp->initial_row)) 394 break; // Stop if we hit an unrecognized opcode 395 } 396 } 397 398 return cie_sp; 399 } 400 401 void DWARFCallFrameInfo::GetCFIData() { 402 if (!m_cfi_data_initialized) { 403 Log *log = GetLog(LLDBLog::Unwind); 404 if (log) 405 m_objfile.GetModule()->LogMessage(log, "Reading EH frame info"); 406 m_objfile.ReadSectionData(m_section_sp.get(), m_cfi_data); 407 m_cfi_data_initialized = true; 408 } 409 } 410 // Scan through the eh_frame or debug_frame section looking for FDEs and noting 411 // the start/end addresses of the functions and a pointer back to the 412 // function's FDE for later expansion. Internalize CIEs as we come across them. 413 414 void DWARFCallFrameInfo::GetFDEIndex() { 415 if (m_section_sp.get() == nullptr || m_section_sp->IsEncrypted()) 416 return; 417 418 if (m_fde_index_initialized) 419 return; 420 421 std::lock_guard<std::mutex> guard(m_fde_index_mutex); 422 423 if (m_fde_index_initialized) // if two threads hit the locker 424 return; 425 426 LLDB_SCOPED_TIMERF("%s", m_objfile.GetFileSpec().GetFilename().AsCString("")); 427 428 bool clear_address_zeroth_bit = false; 429 if (ArchSpec arch = m_objfile.GetArchitecture()) { 430 if (arch.GetTriple().getArch() == llvm::Triple::arm || 431 arch.GetTriple().getArch() == llvm::Triple::thumb) 432 clear_address_zeroth_bit = true; 433 } 434 435 lldb::offset_t offset = 0; 436 if (!m_cfi_data_initialized) 437 GetCFIData(); 438 while (m_cfi_data.ValidOffsetForDataOfSize(offset, 8)) { 439 const dw_offset_t current_entry = offset; 440 dw_offset_t cie_id, next_entry, cie_offset; 441 uint32_t len = m_cfi_data.GetU32(&offset); 442 bool is_64bit = (len == UINT32_MAX); 443 if (is_64bit) { 444 len = m_cfi_data.GetU64(&offset); 445 cie_id = m_cfi_data.GetU64(&offset); 446 next_entry = current_entry + len + 12; 447 cie_offset = current_entry + 12 - cie_id; 448 } else { 449 cie_id = m_cfi_data.GetU32(&offset); 450 next_entry = current_entry + len + 4; 451 cie_offset = current_entry + 4 - cie_id; 452 } 453 454 if (next_entry > m_cfi_data.GetByteSize() + 1) { 455 Debugger::ReportError(llvm::formatv("Invalid fde/cie next entry offset " 456 "of {0:x} found in cie/fde at {1:x}", 457 next_entry, current_entry)); 458 // Don't trust anything in this eh_frame section if we find blatantly 459 // invalid data. 460 m_fde_index.Clear(); 461 m_fde_index_initialized = true; 462 return; 463 } 464 465 // An FDE entry contains CIE_pointer in debug_frame in same place as cie_id 466 // in eh_frame. CIE_pointer is an offset into the .debug_frame section. So, 467 // variable cie_offset should be equal to cie_id for debug_frame. 468 // FDE entries with cie_id == 0 shouldn't be ignored for it. 469 if ((cie_id == 0 && m_type == EH) || cie_id == UINT32_MAX || len == 0) { 470 auto cie_sp = ParseCIE(current_entry); 471 if (!cie_sp) { 472 // Cannot parse, the reason is already logged 473 m_fde_index.Clear(); 474 m_fde_index_initialized = true; 475 return; 476 } 477 478 m_cie_map[current_entry] = std::move(cie_sp); 479 offset = next_entry; 480 continue; 481 } 482 483 if (m_type == DWARF) 484 cie_offset = cie_id; 485 486 if (cie_offset > m_cfi_data.GetByteSize()) { 487 Debugger::ReportError(llvm::formatv("Invalid cie offset of {0:x} " 488 "found in cie/fde at {1:x}", 489 cie_offset, current_entry)); 490 // Don't trust anything in this eh_frame section if we find blatantly 491 // invalid data. 492 m_fde_index.Clear(); 493 m_fde_index_initialized = true; 494 return; 495 } 496 497 const CIE *cie = GetCIE(cie_offset); 498 if (cie) { 499 const lldb::addr_t pc_rel_addr = m_section_sp->GetFileAddress(); 500 const lldb::addr_t text_addr = LLDB_INVALID_ADDRESS; 501 const lldb::addr_t data_addr = LLDB_INVALID_ADDRESS; 502 503 lldb::addr_t addr = 504 GetGNUEHPointer(m_cfi_data, &offset, cie->ptr_encoding, pc_rel_addr, 505 text_addr, data_addr); 506 if (clear_address_zeroth_bit) 507 addr &= ~1ull; 508 509 lldb::addr_t length = GetGNUEHPointer( 510 m_cfi_data, &offset, cie->ptr_encoding & DW_EH_PE_MASK_ENCODING, 511 pc_rel_addr, text_addr, data_addr); 512 FDEEntryMap::Entry fde(addr, length, current_entry); 513 m_fde_index.Append(fde); 514 } else { 515 Debugger::ReportError(llvm::formatv( 516 "unable to find CIE at {0:x} for cie_id = {1:x} for entry at {2:x}.", 517 cie_offset, cie_id, current_entry)); 518 } 519 offset = next_entry; 520 } 521 m_fde_index.Sort(); 522 m_fde_index_initialized = true; 523 } 524 525 bool DWARFCallFrameInfo::FDEToUnwindPlan(dw_offset_t dwarf_offset, 526 Address startaddr, 527 UnwindPlan &unwind_plan) { 528 Log *log = GetLog(LLDBLog::Unwind); 529 lldb::offset_t offset = dwarf_offset; 530 lldb::offset_t current_entry = offset; 531 532 if (m_section_sp.get() == nullptr || m_section_sp->IsEncrypted()) 533 return false; 534 535 if (!m_cfi_data_initialized) 536 GetCFIData(); 537 538 uint32_t length = m_cfi_data.GetU32(&offset); 539 dw_offset_t cie_offset; 540 bool is_64bit = (length == UINT32_MAX); 541 if (is_64bit) { 542 length = m_cfi_data.GetU64(&offset); 543 cie_offset = m_cfi_data.GetU64(&offset); 544 } else { 545 cie_offset = m_cfi_data.GetU32(&offset); 546 } 547 548 // FDE entries with zeroth cie_offset may occur for debug_frame. 549 assert(!(m_type == EH && 0 == cie_offset) && cie_offset != UINT32_MAX); 550 551 // Translate the CIE_id from the eh_frame format, which is relative to the 552 // FDE offset, into a __eh_frame section offset 553 if (m_type == EH) { 554 unwind_plan.SetSourceName("eh_frame CFI"); 555 cie_offset = current_entry + (is_64bit ? 12 : 4) - cie_offset; 556 unwind_plan.SetUnwindPlanValidAtAllInstructions(eLazyBoolNo); 557 } else { 558 unwind_plan.SetSourceName("DWARF CFI"); 559 // In theory the debug_frame info should be valid at all call sites 560 // ("asynchronous unwind info" as it is sometimes called) but in practice 561 // gcc et al all emit call frame info for the prologue and call sites, but 562 // not for the epilogue or all the other locations during the function 563 // reliably. 564 unwind_plan.SetUnwindPlanValidAtAllInstructions(eLazyBoolNo); 565 } 566 unwind_plan.SetSourcedFromCompiler(eLazyBoolYes); 567 568 const CIE *cie = GetCIE(cie_offset); 569 assert(cie != nullptr); 570 571 const dw_offset_t end_offset = current_entry + length + (is_64bit ? 12 : 4); 572 573 const lldb::addr_t pc_rel_addr = m_section_sp->GetFileAddress(); 574 const lldb::addr_t text_addr = LLDB_INVALID_ADDRESS; 575 const lldb::addr_t data_addr = LLDB_INVALID_ADDRESS; 576 lldb::addr_t range_base = 577 GetGNUEHPointer(m_cfi_data, &offset, cie->ptr_encoding, pc_rel_addr, 578 text_addr, data_addr); 579 lldb::addr_t range_len = GetGNUEHPointer( 580 m_cfi_data, &offset, cie->ptr_encoding & DW_EH_PE_MASK_ENCODING, 581 pc_rel_addr, text_addr, data_addr); 582 AddressRange range(range_base, m_objfile.GetAddressByteSize(), 583 m_objfile.GetSectionList()); 584 range.SetByteSize(range_len); 585 586 addr_t lsda_data_file_address = LLDB_INVALID_ADDRESS; 587 588 if (cie->augmentation[0] == 'z') { 589 uint32_t aug_data_len = (uint32_t)m_cfi_data.GetULEB128(&offset); 590 if (aug_data_len != 0 && cie->lsda_addr_encoding != DW_EH_PE_omit) { 591 lldb::offset_t saved_offset = offset; 592 lsda_data_file_address = 593 GetGNUEHPointer(m_cfi_data, &offset, cie->lsda_addr_encoding, 594 pc_rel_addr, text_addr, data_addr); 595 if (offset - saved_offset != aug_data_len) { 596 // There is more in the augmentation region than we know how to process; 597 // don't read anything. 598 lsda_data_file_address = LLDB_INVALID_ADDRESS; 599 } 600 offset = saved_offset; 601 } 602 offset += aug_data_len; 603 } 604 unwind_plan.SetUnwindPlanForSignalTrap( 605 strchr(cie->augmentation, 'S') ? eLazyBoolYes : eLazyBoolNo); 606 607 Address lsda_data; 608 Address personality_function_ptr; 609 610 if (lsda_data_file_address != LLDB_INVALID_ADDRESS && 611 cie->personality_loc != LLDB_INVALID_ADDRESS) { 612 m_objfile.GetModule()->ResolveFileAddress(lsda_data_file_address, 613 lsda_data); 614 m_objfile.GetModule()->ResolveFileAddress(cie->personality_loc, 615 personality_function_ptr); 616 } 617 618 if (lsda_data.IsValid() && personality_function_ptr.IsValid()) { 619 unwind_plan.SetLSDAAddress(lsda_data); 620 unwind_plan.SetPersonalityFunctionPtr(personality_function_ptr); 621 } 622 623 uint32_t code_align = cie->code_align; 624 int32_t data_align = cie->data_align; 625 626 unwind_plan.SetPlanValidAddressRange(range); 627 UnwindPlan::Row *cie_initial_row = new UnwindPlan::Row; 628 *cie_initial_row = cie->initial_row; 629 UnwindPlan::RowSP row(cie_initial_row); 630 631 unwind_plan.SetRegisterKind(GetRegisterKind()); 632 unwind_plan.SetReturnAddressRegister(cie->return_addr_reg_num); 633 634 std::vector<UnwindPlan::RowSP> stack; 635 636 UnwindPlan::Row::AbstractRegisterLocation reg_location; 637 while (m_cfi_data.ValidOffset(offset) && offset < end_offset) { 638 uint8_t inst = m_cfi_data.GetU8(&offset); 639 uint8_t primary_opcode = inst & 0xC0; 640 uint8_t extended_opcode = inst & 0x3F; 641 642 if (!HandleCommonDwarfOpcode(primary_opcode, extended_opcode, data_align, 643 offset, *row)) { 644 if (primary_opcode) { 645 switch (primary_opcode) { 646 case DW_CFA_advance_loc: // (Row Creation Instruction) 647 { // 0x40 - high 2 bits are 0x1, lower 6 bits are delta 648 // takes a single argument that represents a constant delta. The 649 // required action is to create a new table row with a location value 650 // that is computed by taking the current entry's location value and 651 // adding (delta * code_align). All other values in the new row are 652 // initially identical to the current row. 653 unwind_plan.AppendRow(row); 654 UnwindPlan::Row *newrow = new UnwindPlan::Row; 655 *newrow = *row.get(); 656 row.reset(newrow); 657 row->SlideOffset(extended_opcode * code_align); 658 break; 659 } 660 661 case DW_CFA_restore: { // 0xC0 - high 2 bits are 0x3, lower 6 bits are 662 // register 663 // takes a single argument that represents a register number. The 664 // required action is to change the rule for the indicated register 665 // to the rule assigned it by the initial_instructions in the CIE. 666 uint32_t reg_num = extended_opcode; 667 // We only keep enough register locations around to unwind what is in 668 // our thread, and these are organized by the register index in that 669 // state, so we need to convert our eh_frame register number from the 670 // EH frame info, to a register index 671 672 if (unwind_plan.IsValidRowIndex(0) && 673 unwind_plan.GetRowAtIndex(0)->GetRegisterInfo(reg_num, 674 reg_location)) 675 row->SetRegisterInfo(reg_num, reg_location); 676 else { 677 // If the register was not set in the first row, remove the 678 // register info to keep the unmodified value from the caller. 679 row->RemoveRegisterInfo(reg_num); 680 } 681 break; 682 } 683 } 684 } else { 685 switch (extended_opcode) { 686 case DW_CFA_set_loc: // 0x1 (Row Creation Instruction) 687 { 688 // DW_CFA_set_loc takes a single argument that represents an address. 689 // The required action is to create a new table row using the 690 // specified address as the location. All other values in the new row 691 // are initially identical to the current row. The new location value 692 // should always be greater than the current one. 693 unwind_plan.AppendRow(row); 694 UnwindPlan::Row *newrow = new UnwindPlan::Row; 695 *newrow = *row.get(); 696 row.reset(newrow); 697 row->SetOffset(m_cfi_data.GetAddress(&offset) - 698 startaddr.GetFileAddress()); 699 break; 700 } 701 702 case DW_CFA_advance_loc1: // 0x2 (Row Creation Instruction) 703 { 704 // takes a single uword argument that represents a constant delta. 705 // This instruction is identical to DW_CFA_advance_loc except for the 706 // encoding and size of the delta argument. 707 unwind_plan.AppendRow(row); 708 UnwindPlan::Row *newrow = new UnwindPlan::Row; 709 *newrow = *row.get(); 710 row.reset(newrow); 711 row->SlideOffset(m_cfi_data.GetU8(&offset) * code_align); 712 break; 713 } 714 715 case DW_CFA_advance_loc2: // 0x3 (Row Creation Instruction) 716 { 717 // takes a single uword argument that represents a constant delta. 718 // This instruction is identical to DW_CFA_advance_loc except for the 719 // encoding and size of the delta argument. 720 unwind_plan.AppendRow(row); 721 UnwindPlan::Row *newrow = new UnwindPlan::Row; 722 *newrow = *row.get(); 723 row.reset(newrow); 724 row->SlideOffset(m_cfi_data.GetU16(&offset) * code_align); 725 break; 726 } 727 728 case DW_CFA_advance_loc4: // 0x4 (Row Creation Instruction) 729 { 730 // takes a single uword argument that represents a constant delta. 731 // This instruction is identical to DW_CFA_advance_loc except for the 732 // encoding and size of the delta argument. 733 unwind_plan.AppendRow(row); 734 UnwindPlan::Row *newrow = new UnwindPlan::Row; 735 *newrow = *row.get(); 736 row.reset(newrow); 737 row->SlideOffset(m_cfi_data.GetU32(&offset) * code_align); 738 break; 739 } 740 741 case DW_CFA_restore_extended: // 0x6 742 { 743 // takes a single unsigned LEB128 argument that represents a register 744 // number. This instruction is identical to DW_CFA_restore except for 745 // the encoding and size of the register argument. 746 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 747 if (unwind_plan.IsValidRowIndex(0) && 748 unwind_plan.GetRowAtIndex(0)->GetRegisterInfo(reg_num, 749 reg_location)) 750 row->SetRegisterInfo(reg_num, reg_location); 751 break; 752 } 753 754 case DW_CFA_remember_state: // 0xA 755 { 756 // These instructions define a stack of information. Encountering the 757 // DW_CFA_remember_state instruction means to save the rules for 758 // every register on the current row on the stack. Encountering the 759 // DW_CFA_restore_state instruction means to pop the set of rules off 760 // the stack and place them in the current row. (This operation is 761 // useful for compilers that move epilogue code into the body of a 762 // function.) 763 stack.push_back(row); 764 UnwindPlan::Row *newrow = new UnwindPlan::Row; 765 *newrow = *row.get(); 766 row.reset(newrow); 767 break; 768 } 769 770 case DW_CFA_restore_state: // 0xB 771 { 772 // These instructions define a stack of information. Encountering the 773 // DW_CFA_remember_state instruction means to save the rules for 774 // every register on the current row on the stack. Encountering the 775 // DW_CFA_restore_state instruction means to pop the set of rules off 776 // the stack and place them in the current row. (This operation is 777 // useful for compilers that move epilogue code into the body of a 778 // function.) 779 if (stack.empty()) { 780 LLDB_LOG(log, 781 "DWARFCallFrameInfo::{0}(dwarf_offset: " 782 "{1:x16}, startaddr: [{2:x16}] encountered " 783 "DW_CFA_restore_state but state stack " 784 "is empty. Corrupt unwind info?", 785 __FUNCTION__, dwarf_offset, startaddr.GetFileAddress()); 786 break; 787 } 788 lldb::addr_t offset = row->GetOffset(); 789 row = stack.back(); 790 stack.pop_back(); 791 row->SetOffset(offset); 792 break; 793 } 794 795 case DW_CFA_GNU_args_size: // 0x2e 796 { 797 // The DW_CFA_GNU_args_size instruction takes an unsigned LEB128 798 // operand representing an argument size. This instruction specifies 799 // the total of the size of the arguments which have been pushed onto 800 // the stack. 801 802 // TODO: Figure out how we should handle this. 803 m_cfi_data.GetULEB128(&offset); 804 break; 805 } 806 807 case DW_CFA_val_offset: // 0x14 808 case DW_CFA_val_offset_sf: // 0x15 809 default: 810 break; 811 } 812 } 813 } 814 } 815 unwind_plan.AppendRow(row); 816 817 return true; 818 } 819 820 bool DWARFCallFrameInfo::HandleCommonDwarfOpcode(uint8_t primary_opcode, 821 uint8_t extended_opcode, 822 int32_t data_align, 823 lldb::offset_t &offset, 824 UnwindPlan::Row &row) { 825 UnwindPlan::Row::AbstractRegisterLocation reg_location; 826 827 if (primary_opcode) { 828 switch (primary_opcode) { 829 case DW_CFA_offset: { // 0x80 - high 2 bits are 0x2, lower 6 bits are 830 // register 831 // takes two arguments: an unsigned LEB128 constant representing a 832 // factored offset and a register number. The required action is to 833 // change the rule for the register indicated by the register number to 834 // be an offset(N) rule with a value of (N = factored offset * 835 // data_align). 836 uint8_t reg_num = extended_opcode; 837 int32_t op_offset = (int32_t)m_cfi_data.GetULEB128(&offset) * data_align; 838 reg_location.SetAtCFAPlusOffset(op_offset); 839 row.SetRegisterInfo(reg_num, reg_location); 840 return true; 841 } 842 } 843 } else { 844 switch (extended_opcode) { 845 case DW_CFA_nop: // 0x0 846 return true; 847 848 case DW_CFA_offset_extended: // 0x5 849 { 850 // takes two unsigned LEB128 arguments representing a register number and 851 // a factored offset. This instruction is identical to DW_CFA_offset 852 // except for the encoding and size of the register argument. 853 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 854 int32_t op_offset = (int32_t)m_cfi_data.GetULEB128(&offset) * data_align; 855 UnwindPlan::Row::AbstractRegisterLocation reg_location; 856 reg_location.SetAtCFAPlusOffset(op_offset); 857 row.SetRegisterInfo(reg_num, reg_location); 858 return true; 859 } 860 861 case DW_CFA_undefined: // 0x7 862 { 863 // takes a single unsigned LEB128 argument that represents a register 864 // number. The required action is to set the rule for the specified 865 // register to undefined. 866 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 867 UnwindPlan::Row::AbstractRegisterLocation reg_location; 868 reg_location.SetUndefined(); 869 row.SetRegisterInfo(reg_num, reg_location); 870 return true; 871 } 872 873 case DW_CFA_same_value: // 0x8 874 { 875 // takes a single unsigned LEB128 argument that represents a register 876 // number. The required action is to set the rule for the specified 877 // register to same value. 878 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 879 UnwindPlan::Row::AbstractRegisterLocation reg_location; 880 reg_location.SetSame(); 881 row.SetRegisterInfo(reg_num, reg_location); 882 return true; 883 } 884 885 case DW_CFA_register: // 0x9 886 { 887 // takes two unsigned LEB128 arguments representing register numbers. The 888 // required action is to set the rule for the first register to be the 889 // second register. 890 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 891 uint32_t other_reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 892 UnwindPlan::Row::AbstractRegisterLocation reg_location; 893 reg_location.SetInRegister(other_reg_num); 894 row.SetRegisterInfo(reg_num, reg_location); 895 return true; 896 } 897 898 case DW_CFA_def_cfa: // 0xC (CFA Definition Instruction) 899 { 900 // Takes two unsigned LEB128 operands representing a register number and 901 // a (non-factored) offset. The required action is to define the current 902 // CFA rule to use the provided register and offset. 903 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 904 int32_t op_offset = (int32_t)m_cfi_data.GetULEB128(&offset); 905 row.GetCFAValue().SetIsRegisterPlusOffset(reg_num, op_offset); 906 return true; 907 } 908 909 case DW_CFA_def_cfa_register: // 0xD (CFA Definition Instruction) 910 { 911 // takes a single unsigned LEB128 argument representing a register 912 // number. The required action is to define the current CFA rule to use 913 // the provided register (but to keep the old offset). 914 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 915 row.GetCFAValue().SetIsRegisterPlusOffset(reg_num, 916 row.GetCFAValue().GetOffset()); 917 return true; 918 } 919 920 case DW_CFA_def_cfa_offset: // 0xE (CFA Definition Instruction) 921 { 922 // Takes a single unsigned LEB128 operand representing a (non-factored) 923 // offset. The required action is to define the current CFA rule to use 924 // the provided offset (but to keep the old register). 925 int32_t op_offset = (int32_t)m_cfi_data.GetULEB128(&offset); 926 row.GetCFAValue().SetIsRegisterPlusOffset( 927 row.GetCFAValue().GetRegisterNumber(), op_offset); 928 return true; 929 } 930 931 case DW_CFA_def_cfa_expression: // 0xF (CFA Definition Instruction) 932 { 933 size_t block_len = (size_t)m_cfi_data.GetULEB128(&offset); 934 const uint8_t *block_data = 935 static_cast<const uint8_t *>(m_cfi_data.GetData(&offset, block_len)); 936 row.GetCFAValue().SetIsDWARFExpression(block_data, block_len); 937 return true; 938 } 939 940 case DW_CFA_expression: // 0x10 941 { 942 // Takes two operands: an unsigned LEB128 value representing a register 943 // number, and a DW_FORM_block value representing a DWARF expression. The 944 // required action is to change the rule for the register indicated by 945 // the register number to be an expression(E) rule where E is the DWARF 946 // expression. That is, the DWARF expression computes the address. The 947 // value of the CFA is pushed on the DWARF evaluation stack prior to 948 // execution of the DWARF expression. 949 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 950 uint32_t block_len = (uint32_t)m_cfi_data.GetULEB128(&offset); 951 const uint8_t *block_data = 952 static_cast<const uint8_t *>(m_cfi_data.GetData(&offset, block_len)); 953 UnwindPlan::Row::AbstractRegisterLocation reg_location; 954 reg_location.SetAtDWARFExpression(block_data, block_len); 955 row.SetRegisterInfo(reg_num, reg_location); 956 return true; 957 } 958 959 case DW_CFA_offset_extended_sf: // 0x11 960 { 961 // takes two operands: an unsigned LEB128 value representing a register 962 // number and a signed LEB128 factored offset. This instruction is 963 // identical to DW_CFA_offset_extended except that the second operand is 964 // signed and factored. 965 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 966 int32_t op_offset = (int32_t)m_cfi_data.GetSLEB128(&offset) * data_align; 967 UnwindPlan::Row::AbstractRegisterLocation reg_location; 968 reg_location.SetAtCFAPlusOffset(op_offset); 969 row.SetRegisterInfo(reg_num, reg_location); 970 return true; 971 } 972 973 case DW_CFA_def_cfa_sf: // 0x12 (CFA Definition Instruction) 974 { 975 // Takes two operands: an unsigned LEB128 value representing a register 976 // number and a signed LEB128 factored offset. This instruction is 977 // identical to DW_CFA_def_cfa except that the second operand is signed 978 // and factored. 979 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 980 int32_t op_offset = (int32_t)m_cfi_data.GetSLEB128(&offset) * data_align; 981 row.GetCFAValue().SetIsRegisterPlusOffset(reg_num, op_offset); 982 return true; 983 } 984 985 case DW_CFA_def_cfa_offset_sf: // 0x13 (CFA Definition Instruction) 986 { 987 // takes a signed LEB128 operand representing a factored offset. This 988 // instruction is identical to DW_CFA_def_cfa_offset except that the 989 // operand is signed and factored. 990 int32_t op_offset = (int32_t)m_cfi_data.GetSLEB128(&offset) * data_align; 991 uint32_t cfa_regnum = row.GetCFAValue().GetRegisterNumber(); 992 row.GetCFAValue().SetIsRegisterPlusOffset(cfa_regnum, op_offset); 993 return true; 994 } 995 996 case DW_CFA_val_expression: // 0x16 997 { 998 // takes two operands: an unsigned LEB128 value representing a register 999 // number, and a DW_FORM_block value representing a DWARF expression. The 1000 // required action is to change the rule for the register indicated by 1001 // the register number to be a val_expression(E) rule where E is the 1002 // DWARF expression. That is, the DWARF expression computes the value of 1003 // the given register. The value of the CFA is pushed on the DWARF 1004 // evaluation stack prior to execution of the DWARF expression. 1005 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 1006 uint32_t block_len = (uint32_t)m_cfi_data.GetULEB128(&offset); 1007 const uint8_t *block_data = 1008 (const uint8_t *)m_cfi_data.GetData(&offset, block_len); 1009 reg_location.SetIsDWARFExpression(block_data, block_len); 1010 row.SetRegisterInfo(reg_num, reg_location); 1011 return true; 1012 } 1013 } 1014 } 1015 return false; 1016 } 1017 1018 void DWARFCallFrameInfo::ForEachFDEEntries( 1019 const std::function<bool(lldb::addr_t, uint32_t, dw_offset_t)> &callback) { 1020 GetFDEIndex(); 1021 1022 for (size_t i = 0, c = m_fde_index.GetSize(); i < c; ++i) { 1023 const FDEEntryMap::Entry &entry = m_fde_index.GetEntryRef(i); 1024 if (!callback(entry.base, entry.size, entry.data)) 1025 break; 1026 } 1027 } 1028