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