1 //===-- DWARFCallFrameInfo.cpp ----------------------------------*- C++ -*-===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 10 // C Includes 11 // C++ Includes 12 #include <list> 13 14 #include "lldb/Core/ArchSpec.h" 15 #include "lldb/Core/Log.h" 16 #include "lldb/Core/Module.h" 17 #include "lldb/Core/Section.h" 18 #include "lldb/Core/Section.h" 19 #include "lldb/Core/Timer.h" 20 #include "lldb/Host/Host.h" 21 #include "lldb/Symbol/DWARFCallFrameInfo.h" 22 #include "lldb/Symbol/ObjectFile.h" 23 #include "lldb/Symbol/UnwindPlan.h" 24 #include "lldb/Target/RegisterContext.h" 25 #include "lldb/Target/Thread.h" 26 27 using namespace lldb; 28 using namespace lldb_private; 29 30 DWARFCallFrameInfo::DWARFCallFrameInfo(ObjectFile &objfile, 31 SectionSP §ion_sp, 32 lldb::RegisterKind reg_kind, 33 bool is_eh_frame) 34 : m_objfile(objfile), m_section_sp(section_sp), 35 m_reg_kind(reg_kind), // The flavor of registers that the CFI data uses 36 // (enum RegisterKind) 37 m_flags(), m_cie_map(), m_cfi_data(), m_cfi_data_initialized(false), 38 m_fde_index(), m_fde_index_initialized(false), 39 m_is_eh_frame(is_eh_frame) {} 40 41 DWARFCallFrameInfo::~DWARFCallFrameInfo() {} 42 43 bool DWARFCallFrameInfo::GetUnwindPlan(Address addr, UnwindPlan &unwind_plan) { 44 FDEEntryMap::Entry fde_entry; 45 46 // Make sure that the Address we're searching for is the same object file 47 // as this DWARFCallFrameInfo, we only store File offsets in m_fde_index. 48 ModuleSP module_sp = addr.GetModule(); 49 if (module_sp.get() == nullptr || module_sp->GetObjectFile() == nullptr || 50 module_sp->GetObjectFile() != &m_objfile) 51 return false; 52 53 if (GetFDEEntryByFileAddress(addr.GetFileAddress(), fde_entry) == false) 54 return false; 55 return FDEToUnwindPlan(fde_entry.data, addr, unwind_plan); 56 } 57 58 bool DWARFCallFrameInfo::GetAddressRange(Address addr, AddressRange &range) { 59 60 // Make sure that the Address we're searching for is the same object file 61 // as this DWARFCallFrameInfo, we only store File offsets in m_fde_index. 62 ModuleSP module_sp = addr.GetModule(); 63 if (module_sp.get() == nullptr || module_sp->GetObjectFile() == nullptr || 64 module_sp->GetObjectFile() != &m_objfile) 65 return false; 66 67 if (m_section_sp.get() == nullptr || m_section_sp->IsEncrypted()) 68 return false; 69 GetFDEIndex(); 70 FDEEntryMap::Entry *fde_entry = 71 m_fde_index.FindEntryThatContains(addr.GetFileAddress()); 72 if (!fde_entry) 73 return false; 74 75 range = AddressRange(fde_entry->base, fde_entry->size, 76 m_objfile.GetSectionList()); 77 return true; 78 } 79 80 bool DWARFCallFrameInfo::GetFDEEntryByFileAddress( 81 addr_t file_addr, FDEEntryMap::Entry &fde_entry) { 82 if (m_section_sp.get() == nullptr || m_section_sp->IsEncrypted()) 83 return false; 84 85 GetFDEIndex(); 86 87 if (m_fde_index.IsEmpty()) 88 return false; 89 90 FDEEntryMap::Entry *fde = m_fde_index.FindEntryThatContains(file_addr); 91 92 if (fde == nullptr) 93 return false; 94 95 fde_entry = *fde; 96 return true; 97 } 98 99 void DWARFCallFrameInfo::GetFunctionAddressAndSizeVector( 100 FunctionAddressAndSizeVector &function_info) { 101 GetFDEIndex(); 102 const size_t count = m_fde_index.GetSize(); 103 function_info.Clear(); 104 if (count > 0) 105 function_info.Reserve(count); 106 for (size_t i = 0; i < count; ++i) { 107 const FDEEntryMap::Entry *func_offset_data_entry = 108 m_fde_index.GetEntryAtIndex(i); 109 if (func_offset_data_entry) { 110 FunctionAddressAndSizeVector::Entry function_offset_entry( 111 func_offset_data_entry->base, func_offset_data_entry->size); 112 function_info.Append(function_offset_entry); 113 } 114 } 115 } 116 117 const DWARFCallFrameInfo::CIE * 118 DWARFCallFrameInfo::GetCIE(dw_offset_t cie_offset) { 119 cie_map_t::iterator pos = m_cie_map.find(cie_offset); 120 121 if (pos != m_cie_map.end()) { 122 // Parse and cache the CIE 123 if (pos->second.get() == nullptr) 124 pos->second = ParseCIE(cie_offset); 125 126 return pos->second.get(); 127 } 128 return nullptr; 129 } 130 131 DWARFCallFrameInfo::CIESP 132 DWARFCallFrameInfo::ParseCIE(const dw_offset_t cie_offset) { 133 CIESP cie_sp(new CIE(cie_offset)); 134 lldb::offset_t offset = cie_offset; 135 if (m_cfi_data_initialized == false) 136 GetCFIData(); 137 uint32_t length = m_cfi_data.GetU32(&offset); 138 dw_offset_t cie_id, end_offset; 139 bool is_64bit = (length == UINT32_MAX); 140 if (is_64bit) { 141 length = m_cfi_data.GetU64(&offset); 142 cie_id = m_cfi_data.GetU64(&offset); 143 end_offset = cie_offset + length + 12; 144 } else { 145 cie_id = m_cfi_data.GetU32(&offset); 146 end_offset = cie_offset + length + 4; 147 } 148 if (length > 0 && ((!m_is_eh_frame && cie_id == UINT32_MAX) || 149 (m_is_eh_frame && cie_id == 0ul))) { 150 size_t i; 151 // cie.offset = cie_offset; 152 // cie.length = length; 153 // cie.cieID = cieID; 154 cie_sp->ptr_encoding = DW_EH_PE_absptr; // default 155 cie_sp->version = m_cfi_data.GetU8(&offset); 156 157 for (i = 0; i < CFI_AUG_MAX_SIZE; ++i) { 158 cie_sp->augmentation[i] = m_cfi_data.GetU8(&offset); 159 if (cie_sp->augmentation[i] == '\0') { 160 // Zero out remaining bytes in augmentation string 161 for (size_t j = i + 1; j < CFI_AUG_MAX_SIZE; ++j) 162 cie_sp->augmentation[j] = '\0'; 163 164 break; 165 } 166 } 167 168 if (i == CFI_AUG_MAX_SIZE && 169 cie_sp->augmentation[CFI_AUG_MAX_SIZE - 1] != '\0') { 170 Host::SystemLog(Host::eSystemLogError, 171 "CIE parse error: CIE augmentation string was too large " 172 "for the fixed sized buffer of %d bytes.\n", 173 CFI_AUG_MAX_SIZE); 174 return cie_sp; 175 } 176 cie_sp->code_align = (uint32_t)m_cfi_data.GetULEB128(&offset); 177 cie_sp->data_align = (int32_t)m_cfi_data.GetSLEB128(&offset); 178 cie_sp->return_addr_reg_num = m_cfi_data.GetU8(&offset); 179 180 if (cie_sp->augmentation[0]) { 181 // Get the length of the eh_frame augmentation data 182 // which starts with a ULEB128 length in bytes 183 const size_t aug_data_len = (size_t)m_cfi_data.GetULEB128(&offset); 184 const size_t aug_data_end = offset + aug_data_len; 185 const size_t aug_str_len = strlen(cie_sp->augmentation); 186 // A 'z' may be present as the first character of the string. 187 // If present, the Augmentation Data field shall be present. 188 // The contents of the Augmentation Data shall be interpreted 189 // according to other characters in the Augmentation String. 190 if (cie_sp->augmentation[0] == 'z') { 191 // Extract the Augmentation Data 192 size_t aug_str_idx = 0; 193 for (aug_str_idx = 1; aug_str_idx < aug_str_len; aug_str_idx++) { 194 char aug = cie_sp->augmentation[aug_str_idx]; 195 switch (aug) { 196 case 'L': 197 // Indicates the presence of one argument in the 198 // Augmentation Data of the CIE, and a corresponding 199 // argument in the Augmentation Data of the FDE. The 200 // argument in the Augmentation Data of the CIE is 201 // 1-byte and represents the pointer encoding used 202 // for the argument in the Augmentation Data of the 203 // FDE, which is the address of a language-specific 204 // data area (LSDA). The size of the LSDA pointer is 205 // specified by the pointer encoding used. 206 cie_sp->lsda_addr_encoding = m_cfi_data.GetU8(&offset); 207 break; 208 209 case 'P': 210 // Indicates the presence of two arguments in the 211 // Augmentation Data of the CIE. The first argument 212 // is 1-byte and represents the pointer encoding 213 // used for the second argument, which is the 214 // address of a personality routine handler. The 215 // size of the personality routine pointer is 216 // specified by the pointer encoding used. 217 // 218 // The address of the personality function will 219 // be stored at this location. Pre-execution, it 220 // will be all zero's so don't read it until we're 221 // trying to do an unwind & the reloc has been 222 // resolved. 223 { 224 uint8_t arg_ptr_encoding = m_cfi_data.GetU8(&offset); 225 const lldb::addr_t pc_rel_addr = m_section_sp->GetFileAddress(); 226 cie_sp->personality_loc = m_cfi_data.GetGNUEHPointer( 227 &offset, arg_ptr_encoding, pc_rel_addr, LLDB_INVALID_ADDRESS, 228 LLDB_INVALID_ADDRESS); 229 } 230 break; 231 232 case 'R': 233 // A 'R' may be present at any position after the 234 // first character of the string. The Augmentation 235 // Data shall include a 1 byte argument that 236 // represents the pointer encoding for the address 237 // pointers used in the FDE. 238 // Example: 0x1B == DW_EH_PE_pcrel | DW_EH_PE_sdata4 239 cie_sp->ptr_encoding = m_cfi_data.GetU8(&offset); 240 break; 241 } 242 } 243 } else if (strcmp(cie_sp->augmentation, "eh") == 0) { 244 // If the Augmentation string has the value "eh", then 245 // the EH Data field shall be present 246 } 247 248 // Set the offset to be the end of the augmentation data just in case 249 // we didn't understand any of the data. 250 offset = (uint32_t)aug_data_end; 251 } 252 253 if (end_offset > offset) { 254 cie_sp->inst_offset = offset; 255 cie_sp->inst_length = end_offset - offset; 256 } 257 while (offset < end_offset) { 258 uint8_t inst = m_cfi_data.GetU8(&offset); 259 uint8_t primary_opcode = inst & 0xC0; 260 uint8_t extended_opcode = inst & 0x3F; 261 262 if (!HandleCommonDwarfOpcode(primary_opcode, extended_opcode, 263 cie_sp->data_align, offset, 264 cie_sp->initial_row)) 265 break; // Stop if we hit an unrecognized opcode 266 } 267 } 268 269 return cie_sp; 270 } 271 272 void DWARFCallFrameInfo::GetCFIData() { 273 if (m_cfi_data_initialized == false) { 274 Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_UNWIND)); 275 if (log) 276 m_objfile.GetModule()->LogMessage(log, "Reading EH frame info"); 277 m_objfile.ReadSectionData(m_section_sp.get(), m_cfi_data); 278 m_cfi_data_initialized = true; 279 } 280 } 281 // Scan through the eh_frame or debug_frame section looking for FDEs and noting 282 // the start/end addresses 283 // of the functions and a pointer back to the function's FDE for later 284 // expansion. 285 // Internalize CIEs as we come across them. 286 287 void DWARFCallFrameInfo::GetFDEIndex() { 288 if (m_section_sp.get() == nullptr || m_section_sp->IsEncrypted()) 289 return; 290 291 if (m_fde_index_initialized) 292 return; 293 294 std::lock_guard<std::mutex> guard(m_fde_index_mutex); 295 296 if (m_fde_index_initialized) // if two threads hit the locker 297 return; 298 299 Timer scoped_timer(LLVM_PRETTY_FUNCTION, "%s - %s", LLVM_PRETTY_FUNCTION, 300 m_objfile.GetFileSpec().GetFilename().AsCString("")); 301 302 bool clear_address_zeroth_bit = false; 303 ArchSpec arch; 304 if (m_objfile.GetArchitecture(arch)) { 305 if (arch.GetTriple().getArch() == llvm::Triple::arm || 306 arch.GetTriple().getArch() == llvm::Triple::thumb) 307 clear_address_zeroth_bit = true; 308 } 309 310 lldb::offset_t offset = 0; 311 if (m_cfi_data_initialized == false) 312 GetCFIData(); 313 while (m_cfi_data.ValidOffsetForDataOfSize(offset, 8)) { 314 const dw_offset_t current_entry = offset; 315 dw_offset_t cie_id, next_entry, cie_offset; 316 uint32_t len = m_cfi_data.GetU32(&offset); 317 bool is_64bit = (len == UINT32_MAX); 318 if (is_64bit) { 319 len = m_cfi_data.GetU64(&offset); 320 cie_id = m_cfi_data.GetU64(&offset); 321 next_entry = current_entry + len + 12; 322 cie_offset = current_entry + 12 - cie_id; 323 } else { 324 cie_id = m_cfi_data.GetU32(&offset); 325 next_entry = current_entry + len + 4; 326 cie_offset = current_entry + 4 - cie_id; 327 } 328 329 if (next_entry > m_cfi_data.GetByteSize() + 1) { 330 Host::SystemLog(Host::eSystemLogError, "error: Invalid fde/cie next " 331 "entry offset of 0x%x found in " 332 "cie/fde at 0x%x\n", 333 next_entry, current_entry); 334 // Don't trust anything in this eh_frame section if we find blatantly 335 // invalid data. 336 m_fde_index.Clear(); 337 m_fde_index_initialized = true; 338 return; 339 } 340 if (cie_offset > m_cfi_data.GetByteSize()) { 341 Host::SystemLog( 342 Host::eSystemLogError, 343 "error: Invalid cie offset of 0x%x found in cie/fde at 0x%x\n", 344 cie_offset, current_entry); 345 // Don't trust anything in this eh_frame section if we find blatantly 346 // invalid data. 347 m_fde_index.Clear(); 348 m_fde_index_initialized = true; 349 return; 350 } 351 352 if (cie_id == 0 || cie_id == UINT32_MAX || len == 0) { 353 m_cie_map[current_entry] = ParseCIE(current_entry); 354 offset = next_entry; 355 continue; 356 } 357 358 const CIE *cie = GetCIE(cie_offset); 359 if (cie) { 360 const lldb::addr_t pc_rel_addr = m_section_sp->GetFileAddress(); 361 const lldb::addr_t text_addr = LLDB_INVALID_ADDRESS; 362 const lldb::addr_t data_addr = LLDB_INVALID_ADDRESS; 363 364 lldb::addr_t addr = m_cfi_data.GetGNUEHPointer( 365 &offset, cie->ptr_encoding, pc_rel_addr, text_addr, data_addr); 366 if (clear_address_zeroth_bit) 367 addr &= ~1ull; 368 369 lldb::addr_t length = m_cfi_data.GetGNUEHPointer( 370 &offset, cie->ptr_encoding & DW_EH_PE_MASK_ENCODING, pc_rel_addr, 371 text_addr, data_addr); 372 FDEEntryMap::Entry fde(addr, length, current_entry); 373 m_fde_index.Append(fde); 374 } else { 375 Host::SystemLog(Host::eSystemLogError, "error: unable to find CIE at " 376 "0x%8.8x for cie_id = 0x%8.8x for " 377 "entry at 0x%8.8x.\n", 378 cie_offset, cie_id, current_entry); 379 } 380 offset = next_entry; 381 } 382 m_fde_index.Sort(); 383 m_fde_index_initialized = true; 384 } 385 386 bool DWARFCallFrameInfo::FDEToUnwindPlan(dw_offset_t dwarf_offset, 387 Address startaddr, 388 UnwindPlan &unwind_plan) { 389 Log *log = GetLogIfAllCategoriesSet(LIBLLDB_LOG_UNWIND); 390 lldb::offset_t offset = dwarf_offset; 391 lldb::offset_t current_entry = offset; 392 393 if (m_section_sp.get() == nullptr || m_section_sp->IsEncrypted()) 394 return false; 395 396 if (m_cfi_data_initialized == false) 397 GetCFIData(); 398 399 uint32_t length = m_cfi_data.GetU32(&offset); 400 dw_offset_t cie_offset; 401 bool is_64bit = (length == UINT32_MAX); 402 if (is_64bit) { 403 length = m_cfi_data.GetU64(&offset); 404 cie_offset = m_cfi_data.GetU64(&offset); 405 } else { 406 cie_offset = m_cfi_data.GetU32(&offset); 407 } 408 409 assert(cie_offset != 0 && cie_offset != UINT32_MAX); 410 411 // Translate the CIE_id from the eh_frame format, which 412 // is relative to the FDE offset, into a __eh_frame section 413 // offset 414 if (m_is_eh_frame) { 415 unwind_plan.SetSourceName("eh_frame CFI"); 416 cie_offset = current_entry + (is_64bit ? 12 : 4) - cie_offset; 417 unwind_plan.SetUnwindPlanValidAtAllInstructions(eLazyBoolNo); 418 } else { 419 unwind_plan.SetSourceName("DWARF CFI"); 420 // In theory the debug_frame info should be valid at all call sites 421 // ("asynchronous unwind info" as it is sometimes called) but in practice 422 // gcc et al all emit call frame info for the prologue and call sites, but 423 // not for the epilogue or all the other locations during the function 424 // reliably. 425 unwind_plan.SetUnwindPlanValidAtAllInstructions(eLazyBoolNo); 426 } 427 unwind_plan.SetSourcedFromCompiler(eLazyBoolYes); 428 429 const CIE *cie = GetCIE(cie_offset); 430 assert(cie != nullptr); 431 432 const dw_offset_t end_offset = current_entry + length + (is_64bit ? 12 : 4); 433 434 const lldb::addr_t pc_rel_addr = m_section_sp->GetFileAddress(); 435 const lldb::addr_t text_addr = LLDB_INVALID_ADDRESS; 436 const lldb::addr_t data_addr = LLDB_INVALID_ADDRESS; 437 lldb::addr_t range_base = m_cfi_data.GetGNUEHPointer( 438 &offset, cie->ptr_encoding, pc_rel_addr, text_addr, data_addr); 439 lldb::addr_t range_len = m_cfi_data.GetGNUEHPointer( 440 &offset, cie->ptr_encoding & DW_EH_PE_MASK_ENCODING, pc_rel_addr, 441 text_addr, data_addr); 442 AddressRange range(range_base, m_objfile.GetAddressByteSize(), 443 m_objfile.GetSectionList()); 444 range.SetByteSize(range_len); 445 446 addr_t lsda_data_file_address = LLDB_INVALID_ADDRESS; 447 448 if (cie->augmentation[0] == 'z') { 449 uint32_t aug_data_len = (uint32_t)m_cfi_data.GetULEB128(&offset); 450 if (aug_data_len != 0 && cie->lsda_addr_encoding != DW_EH_PE_omit) { 451 offset_t saved_offset = offset; 452 lsda_data_file_address = m_cfi_data.GetGNUEHPointer( 453 &offset, cie->lsda_addr_encoding, pc_rel_addr, text_addr, data_addr); 454 if (offset - saved_offset != aug_data_len) { 455 // There is more in the augmentation region than we know how to process; 456 // don't read anything. 457 lsda_data_file_address = LLDB_INVALID_ADDRESS; 458 } 459 offset = saved_offset; 460 } 461 offset += aug_data_len; 462 } 463 Address lsda_data; 464 Address personality_function_ptr; 465 466 if (lsda_data_file_address != LLDB_INVALID_ADDRESS && 467 cie->personality_loc != LLDB_INVALID_ADDRESS) { 468 m_objfile.GetModule()->ResolveFileAddress(lsda_data_file_address, 469 lsda_data); 470 m_objfile.GetModule()->ResolveFileAddress(cie->personality_loc, 471 personality_function_ptr); 472 } 473 474 if (lsda_data.IsValid() && personality_function_ptr.IsValid()) { 475 unwind_plan.SetLSDAAddress(lsda_data); 476 unwind_plan.SetPersonalityFunctionPtr(personality_function_ptr); 477 } 478 479 uint32_t code_align = cie->code_align; 480 int32_t data_align = cie->data_align; 481 482 unwind_plan.SetPlanValidAddressRange(range); 483 UnwindPlan::Row *cie_initial_row = new UnwindPlan::Row; 484 *cie_initial_row = cie->initial_row; 485 UnwindPlan::RowSP row(cie_initial_row); 486 487 unwind_plan.SetRegisterKind(m_reg_kind); 488 unwind_plan.SetReturnAddressRegister(cie->return_addr_reg_num); 489 490 std::vector<UnwindPlan::RowSP> stack; 491 492 UnwindPlan::Row::RegisterLocation reg_location; 493 while (m_cfi_data.ValidOffset(offset) && offset < end_offset) { 494 uint8_t inst = m_cfi_data.GetU8(&offset); 495 uint8_t primary_opcode = inst & 0xC0; 496 uint8_t extended_opcode = inst & 0x3F; 497 498 if (!HandleCommonDwarfOpcode(primary_opcode, extended_opcode, data_align, 499 offset, *row)) { 500 if (primary_opcode) { 501 switch (primary_opcode) { 502 case DW_CFA_advance_loc: // (Row Creation Instruction) 503 { // 0x40 - high 2 bits are 0x1, lower 6 bits are delta 504 // takes a single argument that represents a constant delta. The 505 // required action is to create a new table row with a location 506 // value that is computed by taking the current entry's location 507 // value and adding (delta * code_align). All other 508 // values in the new row are initially identical to the current row. 509 unwind_plan.AppendRow(row); 510 UnwindPlan::Row *newrow = new UnwindPlan::Row; 511 *newrow = *row.get(); 512 row.reset(newrow); 513 row->SlideOffset(extended_opcode * code_align); 514 break; 515 } 516 517 case DW_CFA_restore: { // 0xC0 - high 2 bits are 0x3, lower 6 bits are 518 // register 519 // takes a single argument that represents a register number. The 520 // required action is to change the rule for the indicated register 521 // to the rule assigned it by the initial_instructions in the CIE. 522 uint32_t reg_num = extended_opcode; 523 // We only keep enough register locations around to 524 // unwind what is in our thread, and these are organized 525 // by the register index in that state, so we need to convert our 526 // eh_frame register number from the EH frame info, to a register 527 // index 528 529 if (unwind_plan.IsValidRowIndex(0) && 530 unwind_plan.GetRowAtIndex(0)->GetRegisterInfo(reg_num, 531 reg_location)) 532 row->SetRegisterInfo(reg_num, reg_location); 533 break; 534 } 535 } 536 } else { 537 switch (extended_opcode) { 538 case DW_CFA_set_loc: // 0x1 (Row Creation Instruction) 539 { 540 // DW_CFA_set_loc takes a single argument that represents an address. 541 // The required action is to create a new table row using the 542 // specified address as the location. All other values in the new row 543 // are initially identical to the current row. The new location value 544 // should always be greater than the current one. 545 unwind_plan.AppendRow(row); 546 UnwindPlan::Row *newrow = new UnwindPlan::Row; 547 *newrow = *row.get(); 548 row.reset(newrow); 549 row->SetOffset(m_cfi_data.GetPointer(&offset) - 550 startaddr.GetFileAddress()); 551 break; 552 } 553 554 case DW_CFA_advance_loc1: // 0x2 (Row Creation Instruction) 555 { 556 // takes a single uword argument that represents a constant delta. 557 // This instruction is identical to DW_CFA_advance_loc except for the 558 // encoding and size of the delta argument. 559 unwind_plan.AppendRow(row); 560 UnwindPlan::Row *newrow = new UnwindPlan::Row; 561 *newrow = *row.get(); 562 row.reset(newrow); 563 row->SlideOffset(m_cfi_data.GetU8(&offset) * code_align); 564 break; 565 } 566 567 case DW_CFA_advance_loc2: // 0x3 (Row Creation Instruction) 568 { 569 // takes a single uword argument that represents a constant delta. 570 // This instruction is identical to DW_CFA_advance_loc except for the 571 // encoding and size of the delta argument. 572 unwind_plan.AppendRow(row); 573 UnwindPlan::Row *newrow = new UnwindPlan::Row; 574 *newrow = *row.get(); 575 row.reset(newrow); 576 row->SlideOffset(m_cfi_data.GetU16(&offset) * code_align); 577 break; 578 } 579 580 case DW_CFA_advance_loc4: // 0x4 (Row Creation Instruction) 581 { 582 // takes a single uword argument that represents a constant delta. 583 // This instruction is identical to DW_CFA_advance_loc except for the 584 // encoding and size of the delta argument. 585 unwind_plan.AppendRow(row); 586 UnwindPlan::Row *newrow = new UnwindPlan::Row; 587 *newrow = *row.get(); 588 row.reset(newrow); 589 row->SlideOffset(m_cfi_data.GetU32(&offset) * code_align); 590 break; 591 } 592 593 case DW_CFA_restore_extended: // 0x6 594 { 595 // takes a single unsigned LEB128 argument that represents a register 596 // number. This instruction is identical to DW_CFA_restore except for 597 // the encoding and size of the register argument. 598 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 599 if (unwind_plan.IsValidRowIndex(0) && 600 unwind_plan.GetRowAtIndex(0)->GetRegisterInfo(reg_num, 601 reg_location)) 602 row->SetRegisterInfo(reg_num, reg_location); 603 break; 604 } 605 606 case DW_CFA_remember_state: // 0xA 607 { 608 // These instructions define a stack of information. Encountering the 609 // DW_CFA_remember_state instruction means to save the rules for every 610 // register on the current row on the stack. Encountering the 611 // DW_CFA_restore_state instruction means to pop the set of rules off 612 // the stack and place them in the current row. (This operation is 613 // useful for compilers that move epilogue code into the body of a 614 // function.) 615 stack.push_back(row); 616 UnwindPlan::Row *newrow = new UnwindPlan::Row; 617 *newrow = *row.get(); 618 row.reset(newrow); 619 break; 620 } 621 622 case DW_CFA_restore_state: // 0xB 623 { 624 // These instructions define a stack of information. Encountering the 625 // DW_CFA_remember_state instruction means to save the rules for every 626 // register on the current row on the stack. Encountering the 627 // DW_CFA_restore_state instruction means to pop the set of rules off 628 // the stack and place them in the current row. (This operation is 629 // useful for compilers that move epilogue code into the body of a 630 // function.) 631 if (stack.empty()) { 632 if (log) 633 log->Printf("DWARFCallFrameInfo::%s(dwarf_offset: %" PRIx32 634 ", startaddr: %" PRIx64 635 " encountered DW_CFA_restore_state but state stack " 636 "is empty. Corrupt unwind info?", 637 __FUNCTION__, dwarf_offset, 638 startaddr.GetFileAddress()); 639 break; 640 } 641 lldb::addr_t offset = row->GetOffset(); 642 row = stack.back(); 643 stack.pop_back(); 644 row->SetOffset(offset); 645 break; 646 } 647 648 case DW_CFA_GNU_args_size: // 0x2e 649 { 650 // The DW_CFA_GNU_args_size instruction takes an unsigned LEB128 651 // operand 652 // representing an argument size. This instruction specifies the total 653 // of 654 // the size of the arguments which have been pushed onto the stack. 655 656 // TODO: Figure out how we should handle this. 657 m_cfi_data.GetULEB128(&offset); 658 break; 659 } 660 661 case DW_CFA_val_offset: // 0x14 662 case DW_CFA_val_offset_sf: // 0x15 663 default: 664 break; 665 } 666 } 667 } 668 } 669 unwind_plan.AppendRow(row); 670 671 return true; 672 } 673 674 bool DWARFCallFrameInfo::HandleCommonDwarfOpcode(uint8_t primary_opcode, 675 uint8_t extended_opcode, 676 int32_t data_align, 677 lldb::offset_t &offset, 678 UnwindPlan::Row &row) { 679 UnwindPlan::Row::RegisterLocation reg_location; 680 681 if (primary_opcode) { 682 switch (primary_opcode) { 683 case DW_CFA_offset: { // 0x80 - high 2 bits are 0x2, lower 6 bits are 684 // register 685 // takes two arguments: an unsigned LEB128 constant representing a 686 // factored offset and a register number. The required action is to 687 // change the rule for the register indicated by the register number 688 // to be an offset(N) rule with a value of 689 // (N = factored offset * data_align). 690 uint8_t reg_num = extended_opcode; 691 int32_t op_offset = (int32_t)m_cfi_data.GetULEB128(&offset) * data_align; 692 reg_location.SetAtCFAPlusOffset(op_offset); 693 row.SetRegisterInfo(reg_num, reg_location); 694 return true; 695 } 696 } 697 } else { 698 switch (extended_opcode) { 699 case DW_CFA_nop: // 0x0 700 return true; 701 702 case DW_CFA_offset_extended: // 0x5 703 { 704 // takes two unsigned LEB128 arguments representing a register number 705 // and a factored offset. This instruction is identical to DW_CFA_offset 706 // except for the encoding and size of the register argument. 707 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 708 int32_t op_offset = (int32_t)m_cfi_data.GetULEB128(&offset) * data_align; 709 UnwindPlan::Row::RegisterLocation reg_location; 710 reg_location.SetAtCFAPlusOffset(op_offset); 711 row.SetRegisterInfo(reg_num, reg_location); 712 return true; 713 } 714 715 case DW_CFA_undefined: // 0x7 716 { 717 // takes a single unsigned LEB128 argument that represents a register 718 // number. The required action is to set the rule for the specified 719 // register to undefined. 720 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 721 UnwindPlan::Row::RegisterLocation reg_location; 722 reg_location.SetUndefined(); 723 row.SetRegisterInfo(reg_num, reg_location); 724 return true; 725 } 726 727 case DW_CFA_same_value: // 0x8 728 { 729 // takes a single unsigned LEB128 argument that represents a register 730 // number. The required action is to set the rule for the specified 731 // register to same value. 732 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 733 UnwindPlan::Row::RegisterLocation reg_location; 734 reg_location.SetSame(); 735 row.SetRegisterInfo(reg_num, reg_location); 736 return true; 737 } 738 739 case DW_CFA_register: // 0x9 740 { 741 // takes two unsigned LEB128 arguments representing register numbers. 742 // The required action is to set the rule for the first register to be 743 // the second register. 744 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 745 uint32_t other_reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 746 UnwindPlan::Row::RegisterLocation reg_location; 747 reg_location.SetInRegister(other_reg_num); 748 row.SetRegisterInfo(reg_num, reg_location); 749 return true; 750 } 751 752 case DW_CFA_def_cfa: // 0xC (CFA Definition Instruction) 753 { 754 // Takes two unsigned LEB128 operands representing a register 755 // number and a (non-factored) offset. The required action 756 // is to define the current CFA rule to use the provided 757 // register and offset. 758 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 759 int32_t op_offset = (int32_t)m_cfi_data.GetULEB128(&offset); 760 row.GetCFAValue().SetIsRegisterPlusOffset(reg_num, op_offset); 761 return true; 762 } 763 764 case DW_CFA_def_cfa_register: // 0xD (CFA Definition Instruction) 765 { 766 // takes a single unsigned LEB128 argument representing a register 767 // number. The required action is to define the current CFA rule to 768 // use the provided register (but to keep the old offset). 769 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 770 row.GetCFAValue().SetIsRegisterPlusOffset(reg_num, 771 row.GetCFAValue().GetOffset()); 772 return true; 773 } 774 775 case DW_CFA_def_cfa_offset: // 0xE (CFA Definition Instruction) 776 { 777 // Takes a single unsigned LEB128 operand representing a 778 // (non-factored) offset. The required action is to define 779 // the current CFA rule to use the provided offset (but 780 // to keep the old register). 781 int32_t op_offset = (int32_t)m_cfi_data.GetULEB128(&offset); 782 row.GetCFAValue().SetIsRegisterPlusOffset( 783 row.GetCFAValue().GetRegisterNumber(), op_offset); 784 return true; 785 } 786 787 case DW_CFA_def_cfa_expression: // 0xF (CFA Definition Instruction) 788 { 789 size_t block_len = (size_t)m_cfi_data.GetULEB128(&offset); 790 const uint8_t *block_data = 791 static_cast<const uint8_t *>(m_cfi_data.GetData(&offset, block_len)); 792 row.GetCFAValue().SetIsDWARFExpression(block_data, block_len); 793 return true; 794 } 795 796 case DW_CFA_expression: // 0x10 797 { 798 // Takes two operands: an unsigned LEB128 value representing 799 // a register number, and a DW_FORM_block value representing a DWARF 800 // expression. The required action is to change the rule for the 801 // register indicated by the register number to be an expression(E) 802 // rule where E is the DWARF expression. That is, the DWARF 803 // expression computes the address. The value of the CFA is 804 // pushed on the DWARF evaluation stack prior to execution of 805 // the DWARF expression. 806 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 807 uint32_t block_len = (uint32_t)m_cfi_data.GetULEB128(&offset); 808 const uint8_t *block_data = 809 static_cast<const uint8_t *>(m_cfi_data.GetData(&offset, block_len)); 810 UnwindPlan::Row::RegisterLocation reg_location; 811 reg_location.SetAtDWARFExpression(block_data, block_len); 812 row.SetRegisterInfo(reg_num, reg_location); 813 return true; 814 } 815 816 case DW_CFA_offset_extended_sf: // 0x11 817 { 818 // takes two operands: an unsigned LEB128 value representing a 819 // register number and a signed LEB128 factored offset. This 820 // instruction is identical to DW_CFA_offset_extended except 821 // that the second operand is signed and factored. 822 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 823 int32_t op_offset = (int32_t)m_cfi_data.GetSLEB128(&offset) * data_align; 824 UnwindPlan::Row::RegisterLocation reg_location; 825 reg_location.SetAtCFAPlusOffset(op_offset); 826 row.SetRegisterInfo(reg_num, reg_location); 827 return true; 828 } 829 830 case DW_CFA_def_cfa_sf: // 0x12 (CFA Definition Instruction) 831 { 832 // Takes two operands: an unsigned LEB128 value representing 833 // a register number and a signed LEB128 factored offset. 834 // This instruction is identical to DW_CFA_def_cfa except 835 // that the second operand is signed and factored. 836 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 837 int32_t op_offset = (int32_t)m_cfi_data.GetSLEB128(&offset) * data_align; 838 row.GetCFAValue().SetIsRegisterPlusOffset(reg_num, op_offset); 839 return true; 840 } 841 842 case DW_CFA_def_cfa_offset_sf: // 0x13 (CFA Definition Instruction) 843 { 844 // takes a signed LEB128 operand representing a factored 845 // offset. This instruction is identical to DW_CFA_def_cfa_offset 846 // except that the operand is signed and factored. 847 int32_t op_offset = (int32_t)m_cfi_data.GetSLEB128(&offset) * data_align; 848 uint32_t cfa_regnum = row.GetCFAValue().GetRegisterNumber(); 849 row.GetCFAValue().SetIsRegisterPlusOffset(cfa_regnum, op_offset); 850 return true; 851 } 852 853 case DW_CFA_val_expression: // 0x16 854 { 855 // takes two operands: an unsigned LEB128 value representing a register 856 // number, and a DW_FORM_block value representing a DWARF expression. 857 // The required action is to change the rule for the register indicated 858 // by the register number to be a val_expression(E) rule where E is the 859 // DWARF expression. That is, the DWARF expression computes the value of 860 // the given register. The value of the CFA is pushed on the DWARF 861 // evaluation stack prior to execution of the DWARF expression. 862 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 863 uint32_t block_len = (uint32_t)m_cfi_data.GetULEB128(&offset); 864 const uint8_t *block_data = 865 (const uint8_t *)m_cfi_data.GetData(&offset, block_len); 866 //#if defined(__i386__) || defined(__x86_64__) 867 // // The EH frame info for EIP and RIP contains code that 868 // looks for traps to 869 // // be a specific type and increments the PC. 870 // // For i386: 871 // // DW_CFA_val_expression where: 872 // // eip = DW_OP_breg6(+28), DW_OP_deref, DW_OP_dup, 873 // DW_OP_plus_uconst(0x34), 874 // // DW_OP_deref, DW_OP_swap, DW_OP_plus_uconst(0), 875 // DW_OP_deref, 876 // // DW_OP_dup, DW_OP_lit3, DW_OP_ne, DW_OP_swap, 877 // DW_OP_lit4, DW_OP_ne, 878 // // DW_OP_and, DW_OP_plus 879 // // This basically does a: 880 // // eip = ucontenxt.mcontext32->gpr.eip; 881 // // if (ucontenxt.mcontext32->exc.trapno != 3 && 882 // ucontenxt.mcontext32->exc.trapno != 4) 883 // // eip++; 884 // // 885 // // For x86_64: 886 // // DW_CFA_val_expression where: 887 // // rip = DW_OP_breg3(+48), DW_OP_deref, DW_OP_dup, 888 // DW_OP_plus_uconst(0x90), DW_OP_deref, 889 // // DW_OP_swap, DW_OP_plus_uconst(0), 890 // DW_OP_deref_size(4), DW_OP_dup, DW_OP_lit3, 891 // // DW_OP_ne, DW_OP_swap, DW_OP_lit4, DW_OP_ne, 892 // DW_OP_and, DW_OP_plus 893 // // This basically does a: 894 // // rip = ucontenxt.mcontext64->gpr.rip; 895 // // if (ucontenxt.mcontext64->exc.trapno != 3 && 896 // ucontenxt.mcontext64->exc.trapno != 4) 897 // // rip++; 898 // // The trap comparisons and increments are not needed as 899 // it hoses up the unwound PC which 900 // // is expected to point at least past the instruction that 901 // causes the fault/trap. So we 902 // // take it out by trimming the expression right at the 903 // first "DW_OP_swap" opcodes 904 // if (block_data != NULL && thread->GetPCRegNum(Thread::GCC) 905 // == reg_num) 906 // { 907 // if (thread->Is64Bit()) 908 // { 909 // if (block_len > 9 && block_data[8] == DW_OP_swap 910 // && block_data[9] == DW_OP_plus_uconst) 911 // block_len = 8; 912 // } 913 // else 914 // { 915 // if (block_len > 8 && block_data[7] == DW_OP_swap 916 // && block_data[8] == DW_OP_plus_uconst) 917 // block_len = 7; 918 // } 919 // } 920 //#endif 921 reg_location.SetIsDWARFExpression(block_data, block_len); 922 row.SetRegisterInfo(reg_num, reg_location); 923 return true; 924 } 925 } 926 } 927 return false; 928 } 929 930 void DWARFCallFrameInfo::ForEachFDEEntries( 931 const std::function<bool(lldb::addr_t, uint32_t, dw_offset_t)> &callback) { 932 GetFDEIndex(); 933 934 for (size_t i = 0, c = m_fde_index.GetSize(); i < c; ++i) { 935 const FDEEntryMap::Entry &entry = m_fde_index.GetEntryRef(i); 936 if (!callback(entry.base, entry.size, entry.data)) 937 break; 938 } 939 } 940