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.SetCFARegister (reg_num); 288 cie_sp->initial_row.SetCFAOffset (op_offset); 289 continue; 290 } 291 if (primary_opcode == DW_CFA_offset) 292 { 293 // 0x80 - high 2 bits are 0x2, lower 6 bits are register. 294 // Takes two arguments: an unsigned LEB128 constant representing a 295 // factored offset and a register number. The required action is to 296 // change the rule for the register indicated by the register number 297 // to be an offset(N) rule with a value of 298 // (N = factored offset * data_align). 299 uint32_t reg_num = extended_opcode; 300 int op_offset = (int32_t)m_cfi_data.GetULEB128(&offset) * cie_sp->data_align; 301 UnwindPlan::Row::RegisterLocation reg_location; 302 reg_location.SetAtCFAPlusOffset(op_offset); 303 cie_sp->initial_row.SetRegisterInfo (reg_num, reg_location); 304 continue; 305 } 306 if (extended_opcode == DW_CFA_nop) 307 { 308 continue; 309 } 310 break; // Stop if we hit an unrecognized opcode 311 } 312 } 313 314 return cie_sp; 315 } 316 317 void 318 DWARFCallFrameInfo::GetCFIData() 319 { 320 if (m_cfi_data_initialized == false) 321 { 322 Log *log(GetLogIfAllCategoriesSet (LIBLLDB_LOG_UNWIND)); 323 if (log) 324 m_objfile.GetModule()->LogMessage(log, "Reading EH frame info"); 325 m_objfile.ReadSectionData (m_section_sp.get(), m_cfi_data); 326 m_cfi_data_initialized = true; 327 } 328 } 329 // Scan through the eh_frame or debug_frame section looking for FDEs and noting the start/end addresses 330 // of the functions and a pointer back to the function's FDE for later expansion. 331 // Internalize CIEs as we come across them. 332 333 void 334 DWARFCallFrameInfo::GetFDEIndex () 335 { 336 if (m_section_sp.get() == nullptr || m_section_sp->IsEncrypted()) 337 return; 338 339 if (m_fde_index_initialized) 340 return; 341 342 Mutex::Locker locker(m_fde_index_mutex); 343 344 if (m_fde_index_initialized) // if two threads hit the locker 345 return; 346 347 Timer scoped_timer (__PRETTY_FUNCTION__, "%s - %s", __PRETTY_FUNCTION__, m_objfile.GetFileSpec().GetFilename().AsCString("")); 348 349 lldb::offset_t offset = 0; 350 if (m_cfi_data_initialized == false) 351 GetCFIData(); 352 while (m_cfi_data.ValidOffsetForDataOfSize (offset, 8)) 353 { 354 const dw_offset_t current_entry = offset; 355 dw_offset_t cie_id, next_entry, cie_offset; 356 uint32_t len = m_cfi_data.GetU32 (&offset); 357 bool is_64bit = (len == UINT32_MAX); 358 if (is_64bit) { 359 len = m_cfi_data.GetU64 (&offset); 360 cie_id = m_cfi_data.GetU64 (&offset); 361 next_entry = current_entry + len + 12; 362 cie_offset = current_entry + 12 - cie_id; 363 } else { 364 cie_id = m_cfi_data.GetU32 (&offset); 365 next_entry = current_entry + len + 4; 366 cie_offset = current_entry + 4 - cie_id; 367 } 368 369 if (cie_id == 0 || cie_id == UINT32_MAX || len == 0) 370 { 371 m_cie_map[current_entry] = ParseCIE (current_entry); 372 offset = next_entry; 373 continue; 374 } 375 376 const CIE *cie = GetCIE (cie_offset); 377 if (cie) 378 { 379 const lldb::addr_t pc_rel_addr = m_section_sp->GetFileAddress(); 380 const lldb::addr_t text_addr = LLDB_INVALID_ADDRESS; 381 const lldb::addr_t data_addr = LLDB_INVALID_ADDRESS; 382 383 lldb::addr_t addr = m_cfi_data.GetGNUEHPointer(&offset, cie->ptr_encoding, pc_rel_addr, text_addr, data_addr); 384 lldb::addr_t length = m_cfi_data.GetGNUEHPointer(&offset, cie->ptr_encoding & DW_EH_PE_MASK_ENCODING, pc_rel_addr, text_addr, data_addr); 385 FDEEntryMap::Entry fde (addr, length, current_entry); 386 m_fde_index.Append(fde); 387 } 388 else 389 { 390 Host::SystemLog (Host::eSystemLogError, 391 "error: unable to find CIE at 0x%8.8x for cie_id = 0x%8.8x for entry at 0x%8.8x.\n", 392 cie_offset, 393 cie_id, 394 current_entry); 395 } 396 offset = next_entry; 397 } 398 m_fde_index.Sort(); 399 m_fde_index_initialized = true; 400 } 401 402 bool 403 DWARFCallFrameInfo::FDEToUnwindPlan (dw_offset_t dwarf_offset, Address startaddr, UnwindPlan& unwind_plan) 404 { 405 lldb::offset_t offset = dwarf_offset; 406 lldb::offset_t current_entry = offset; 407 408 if (m_section_sp.get() == nullptr || m_section_sp->IsEncrypted()) 409 return false; 410 411 if (m_cfi_data_initialized == false) 412 GetCFIData(); 413 414 uint32_t length = m_cfi_data.GetU32 (&offset); 415 dw_offset_t cie_offset; 416 bool is_64bit = (length == UINT32_MAX); 417 if (is_64bit) { 418 length = m_cfi_data.GetU64 (&offset); 419 cie_offset = m_cfi_data.GetU64 (&offset); 420 } else { 421 cie_offset = m_cfi_data.GetU32 (&offset); 422 } 423 424 assert (cie_offset != 0 && cie_offset != UINT32_MAX); 425 426 // Translate the CIE_id from the eh_frame format, which 427 // is relative to the FDE offset, into a __eh_frame section 428 // offset 429 if (m_is_eh_frame) 430 { 431 unwind_plan.SetSourceName ("eh_frame CFI"); 432 cie_offset = current_entry + (is_64bit ? 12 : 4) - cie_offset; 433 unwind_plan.SetUnwindPlanValidAtAllInstructions (eLazyBoolNo); 434 } 435 else 436 { 437 unwind_plan.SetSourceName ("DWARF CFI"); 438 // In theory the debug_frame info should be valid at all call sites 439 // ("asynchronous unwind info" as it is sometimes called) but in practice 440 // gcc et al all emit call frame info for the prologue and call sites, but 441 // not for the epilogue or all the other locations during the function reliably. 442 unwind_plan.SetUnwindPlanValidAtAllInstructions (eLazyBoolNo); 443 } 444 unwind_plan.SetSourcedFromCompiler (eLazyBoolYes); 445 446 const CIE *cie = GetCIE (cie_offset); 447 assert (cie != nullptr); 448 449 const dw_offset_t end_offset = current_entry + length + (is_64bit ? 12 : 4); 450 451 const lldb::addr_t pc_rel_addr = m_section_sp->GetFileAddress(); 452 const lldb::addr_t text_addr = LLDB_INVALID_ADDRESS; 453 const lldb::addr_t data_addr = LLDB_INVALID_ADDRESS; 454 lldb::addr_t range_base = m_cfi_data.GetGNUEHPointer(&offset, cie->ptr_encoding, pc_rel_addr, text_addr, data_addr); 455 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); 456 AddressRange range (range_base, m_objfile.GetAddressByteSize(), m_objfile.GetSectionList()); 457 range.SetByteSize (range_len); 458 459 addr_t lsda_data_file_address = LLDB_INVALID_ADDRESS; 460 461 if (cie->augmentation[0] == 'z') 462 { 463 uint32_t aug_data_len = (uint32_t)m_cfi_data.GetULEB128(&offset); 464 if (aug_data_len != 0 && cie->lsda_addr_encoding != DW_EH_PE_omit) 465 { 466 offset_t saved_offset = offset; 467 lsda_data_file_address = m_cfi_data.GetGNUEHPointer(&offset, cie->lsda_addr_encoding, pc_rel_addr, text_addr, data_addr); 468 if (offset - saved_offset != aug_data_len) 469 { 470 // There is more in the augmentation region than we know how to process; 471 // don't read anything. 472 lsda_data_file_address = LLDB_INVALID_ADDRESS; 473 } 474 offset = saved_offset; 475 } 476 offset += aug_data_len; 477 } 478 Address lsda_data; 479 Address personality_function_ptr; 480 481 if (lsda_data_file_address != LLDB_INVALID_ADDRESS && cie->personality_loc != LLDB_INVALID_ADDRESS) 482 { 483 m_objfile.GetModule()->ResolveFileAddress (lsda_data_file_address, lsda_data); 484 m_objfile.GetModule()->ResolveFileAddress (cie->personality_loc, personality_function_ptr); 485 } 486 487 if (lsda_data.IsValid() && personality_function_ptr.IsValid()) 488 { 489 unwind_plan.SetLSDAAddress (lsda_data); 490 unwind_plan.SetPersonalityFunctionPtr (personality_function_ptr); 491 } 492 493 uint32_t reg_num = 0; 494 int32_t op_offset = 0; 495 uint32_t code_align = cie->code_align; 496 int32_t data_align = cie->data_align; 497 498 unwind_plan.SetPlanValidAddressRange (range); 499 UnwindPlan::Row *cie_initial_row = new UnwindPlan::Row; 500 *cie_initial_row = cie->initial_row; 501 UnwindPlan::RowSP row(cie_initial_row); 502 503 unwind_plan.SetRegisterKind (m_reg_kind); 504 unwind_plan.SetReturnAddressRegister (cie->return_addr_reg_num); 505 506 std::vector<UnwindPlan::RowSP> stack; 507 508 UnwindPlan::Row::RegisterLocation reg_location; 509 while (m_cfi_data.ValidOffset(offset) && offset < end_offset) 510 { 511 uint8_t inst = m_cfi_data.GetU8(&offset); 512 uint8_t primary_opcode = inst & 0xC0; 513 uint8_t extended_opcode = inst & 0x3F; 514 515 if (primary_opcode) 516 { 517 switch (primary_opcode) 518 { 519 case DW_CFA_advance_loc : // (Row Creation Instruction) 520 { // 0x40 - high 2 bits are 0x1, lower 6 bits are delta 521 // takes a single argument that represents a constant delta. The 522 // required action is to create a new table row with a location 523 // value that is computed by taking the current entry's location 524 // value and adding (delta * code_align). All other 525 // values in the new row are initially identical to the current row. 526 unwind_plan.AppendRow(row); 527 UnwindPlan::Row *newrow = new UnwindPlan::Row; 528 *newrow = *row.get(); 529 row.reset (newrow); 530 row->SlideOffset(extended_opcode * code_align); 531 } 532 break; 533 534 case DW_CFA_offset : 535 { // 0x80 - high 2 bits are 0x2, lower 6 bits are register 536 // takes two arguments: an unsigned LEB128 constant representing a 537 // factored offset and a register number. The required action is to 538 // change the rule for the register indicated by the register number 539 // to be an offset(N) rule with a value of 540 // (N = factored offset * data_align). 541 reg_num = extended_opcode; 542 op_offset = (int32_t)m_cfi_data.GetULEB128(&offset) * data_align; 543 reg_location.SetAtCFAPlusOffset(op_offset); 544 row->SetRegisterInfo (reg_num, reg_location); 545 } 546 break; 547 548 case DW_CFA_restore : 549 { // 0xC0 - high 2 bits are 0x3, lower 6 bits are register 550 // takes a single argument that represents a register number. The 551 // required action is to change the rule for the indicated register 552 // to the rule assigned it by the initial_instructions in the CIE. 553 reg_num = extended_opcode; 554 // We only keep enough register locations around to 555 // unwind what is in our thread, and these are organized 556 // by the register index in that state, so we need to convert our 557 // GCC register number from the EH frame info, to a register index 558 559 if (unwind_plan.IsValidRowIndex(0) && unwind_plan.GetRowAtIndex(0)->GetRegisterInfo(reg_num, reg_location)) 560 row->SetRegisterInfo (reg_num, reg_location); 561 } 562 break; 563 } 564 } 565 else 566 { 567 switch (extended_opcode) 568 { 569 case DW_CFA_nop : // 0x0 570 break; 571 572 case DW_CFA_set_loc : // 0x1 (Row Creation Instruction) 573 { 574 // DW_CFA_set_loc takes a single argument that represents an address. 575 // The required action is to create a new table row using the 576 // specified address as the location. All other values in the new row 577 // are initially identical to the current row. The new location value 578 // should always be greater than the current one. 579 unwind_plan.AppendRow(row); 580 UnwindPlan::Row *newrow = new UnwindPlan::Row; 581 *newrow = *row.get(); 582 row.reset (newrow); 583 row->SetOffset(m_cfi_data.GetPointer(&offset) - startaddr.GetFileAddress()); 584 } 585 break; 586 587 case DW_CFA_advance_loc1 : // 0x2 (Row Creation Instruction) 588 { 589 // takes a single uword argument that represents a constant delta. 590 // This instruction is identical to DW_CFA_advance_loc except for the 591 // encoding and size of the delta argument. 592 unwind_plan.AppendRow(row); 593 UnwindPlan::Row *newrow = new UnwindPlan::Row; 594 *newrow = *row.get(); 595 row.reset (newrow); 596 row->SlideOffset (m_cfi_data.GetU8(&offset) * code_align); 597 } 598 break; 599 600 case DW_CFA_advance_loc2 : // 0x3 (Row Creation Instruction) 601 { 602 // takes a single uword argument that represents a constant delta. 603 // This instruction is identical to DW_CFA_advance_loc except for the 604 // encoding and size of the delta argument. 605 unwind_plan.AppendRow(row); 606 UnwindPlan::Row *newrow = new UnwindPlan::Row; 607 *newrow = *row.get(); 608 row.reset (newrow); 609 row->SlideOffset (m_cfi_data.GetU16(&offset) * code_align); 610 } 611 break; 612 613 case DW_CFA_advance_loc4 : // 0x4 (Row Creation Instruction) 614 { 615 // takes a single uword argument that represents a constant delta. 616 // This instruction is identical to DW_CFA_advance_loc except for the 617 // encoding and size of the delta argument. 618 unwind_plan.AppendRow(row); 619 UnwindPlan::Row *newrow = new UnwindPlan::Row; 620 *newrow = *row.get(); 621 row.reset (newrow); 622 row->SlideOffset (m_cfi_data.GetU32(&offset) * code_align); 623 } 624 break; 625 626 case DW_CFA_offset_extended : // 0x5 627 { 628 // takes two unsigned LEB128 arguments representing a register number 629 // and a factored offset. This instruction is identical to DW_CFA_offset 630 // except for the encoding and size of the register argument. 631 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 632 op_offset = (int32_t)m_cfi_data.GetULEB128(&offset) * data_align; 633 reg_location.SetAtCFAPlusOffset(op_offset); 634 row->SetRegisterInfo (reg_num, reg_location); 635 } 636 break; 637 638 case DW_CFA_restore_extended : // 0x6 639 { 640 // takes a single unsigned LEB128 argument that represents a register 641 // number. This instruction is identical to DW_CFA_restore except for 642 // the encoding and size of the register argument. 643 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 644 if (unwind_plan.IsValidRowIndex(0) && unwind_plan.GetRowAtIndex(0)->GetRegisterInfo(reg_num, reg_location)) 645 row->SetRegisterInfo (reg_num, reg_location); 646 } 647 break; 648 649 case DW_CFA_undefined : // 0x7 650 { 651 // takes a single unsigned LEB128 argument that represents a register 652 // number. The required action is to set the rule for the specified 653 // register to undefined. 654 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 655 reg_location.SetUndefined(); 656 row->SetRegisterInfo (reg_num, reg_location); 657 } 658 break; 659 660 case DW_CFA_same_value : // 0x8 661 { 662 // takes a single unsigned LEB128 argument that represents a register 663 // number. The required action is to set the rule for the specified 664 // register to same value. 665 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 666 reg_location.SetSame(); 667 row->SetRegisterInfo (reg_num, reg_location); 668 } 669 break; 670 671 case DW_CFA_register : // 0x9 672 { 673 // takes two unsigned LEB128 arguments representing register numbers. 674 // The required action is to set the rule for the first register to be 675 // the second register. 676 677 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 678 uint32_t other_reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 679 reg_location.SetInRegister(other_reg_num); 680 row->SetRegisterInfo (reg_num, reg_location); 681 } 682 break; 683 684 case DW_CFA_remember_state : // 0xA 685 { 686 // These instructions define a stack of information. Encountering the 687 // DW_CFA_remember_state instruction means to save the rules for every 688 // register on the current row on the stack. Encountering the 689 // DW_CFA_restore_state instruction means to pop the set of rules off 690 // the stack and place them in the current row. (This operation is 691 // useful for compilers that move epilogue code into the body of a 692 // function.) 693 stack.push_back (row); 694 UnwindPlan::Row *newrow = new UnwindPlan::Row; 695 *newrow = *row.get(); 696 row.reset (newrow); 697 } 698 break; 699 700 case DW_CFA_restore_state : // 0xB 701 // These instructions define a stack of information. Encountering the 702 // DW_CFA_remember_state instruction means to save the rules for every 703 // register on the current row on the stack. Encountering the 704 // DW_CFA_restore_state instruction means to pop the set of rules off 705 // the stack and place them in the current row. (This operation is 706 // useful for compilers that move epilogue code into the body of a 707 // function.) 708 { 709 row = stack.back (); 710 stack.pop_back (); 711 } 712 break; 713 714 case DW_CFA_def_cfa : // 0xC (CFA Definition Instruction) 715 { 716 // Takes two unsigned LEB128 operands representing a register 717 // number and a (non-factored) offset. The required action 718 // is to define the current CFA rule to use the provided 719 // register and offset. 720 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 721 op_offset = (int32_t)m_cfi_data.GetULEB128(&offset); 722 row->SetCFARegister (reg_num); 723 row->SetCFAOffset (op_offset); 724 } 725 break; 726 727 case DW_CFA_def_cfa_register : // 0xD (CFA Definition Instruction) 728 { 729 // takes a single unsigned LEB128 argument representing a register 730 // number. The required action is to define the current CFA rule to 731 // use the provided register (but to keep the old offset). 732 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 733 row->SetCFARegister (reg_num); 734 } 735 break; 736 737 case DW_CFA_def_cfa_offset : // 0xE (CFA Definition Instruction) 738 { 739 // Takes a single unsigned LEB128 operand representing a 740 // (non-factored) offset. The required action is to define 741 // the current CFA rule to use the provided offset (but 742 // to keep the old register). 743 op_offset = (int32_t)m_cfi_data.GetULEB128(&offset); 744 row->SetCFAOffset (op_offset); 745 } 746 break; 747 748 case DW_CFA_def_cfa_expression : // 0xF (CFA Definition Instruction) 749 { 750 size_t block_len = (size_t)m_cfi_data.GetULEB128(&offset); 751 offset += (uint32_t)block_len; 752 } 753 break; 754 755 case DW_CFA_expression : // 0x10 756 { 757 // Takes two operands: an unsigned LEB128 value representing 758 // a register number, and a DW_FORM_block value representing a DWARF 759 // expression. The required action is to change the rule for the 760 // register indicated by the register number to be an expression(E) 761 // rule where E is the DWARF expression. That is, the DWARF 762 // expression computes the address. The value of the CFA is 763 // pushed on the DWARF evaluation stack prior to execution of 764 // the DWARF expression. 765 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 766 uint32_t block_len = (uint32_t)m_cfi_data.GetULEB128(&offset); 767 const uint8_t *block_data = (uint8_t *)m_cfi_data.GetData(&offset, block_len); 768 769 reg_location.SetAtDWARFExpression(block_data, block_len); 770 row->SetRegisterInfo (reg_num, reg_location); 771 } 772 break; 773 774 case DW_CFA_offset_extended_sf : // 0x11 775 { 776 // takes two operands: an unsigned LEB128 value representing a 777 // register number and a signed LEB128 factored offset. This 778 // instruction is identical to DW_CFA_offset_extended except 779 //that the second operand is signed and factored. 780 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 781 op_offset = (int32_t)m_cfi_data.GetSLEB128(&offset) * data_align; 782 reg_location.SetAtCFAPlusOffset(op_offset); 783 row->SetRegisterInfo (reg_num, reg_location); 784 } 785 break; 786 787 case DW_CFA_def_cfa_sf : // 0x12 (CFA Definition Instruction) 788 { 789 // Takes two operands: an unsigned LEB128 value representing 790 // a register number and a signed LEB128 factored offset. 791 // This instruction is identical to DW_CFA_def_cfa except 792 // that the second operand is signed and factored. 793 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 794 op_offset = (int32_t)m_cfi_data.GetSLEB128(&offset) * data_align; 795 row->SetCFARegister (reg_num); 796 row->SetCFAOffset (op_offset); 797 } 798 break; 799 800 case DW_CFA_def_cfa_offset_sf : // 0x13 (CFA Definition Instruction) 801 { 802 // takes a signed LEB128 operand representing a factored 803 // offset. This instruction is identical to DW_CFA_def_cfa_offset 804 // except that the operand is signed and factored. 805 op_offset = (int32_t)m_cfi_data.GetSLEB128(&offset) * data_align; 806 row->SetCFAOffset (op_offset); 807 } 808 break; 809 810 case DW_CFA_val_expression : // 0x16 811 { 812 // takes two operands: an unsigned LEB128 value representing a register 813 // number, and a DW_FORM_block value representing a DWARF expression. 814 // The required action is to change the rule for the register indicated 815 // by the register number to be a val_expression(E) rule where E is the 816 // DWARF expression. That is, the DWARF expression computes the value of 817 // the given register. The value of the CFA is pushed on the DWARF 818 // evaluation stack prior to execution of the DWARF expression. 819 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 820 uint32_t block_len = (uint32_t)m_cfi_data.GetULEB128(&offset); 821 const uint8_t* block_data = (uint8_t*)m_cfi_data.GetData(&offset, block_len); 822 //#if defined(__i386__) || defined(__x86_64__) 823 // // The EH frame info for EIP and RIP contains code that looks for traps to 824 // // be a specific type and increments the PC. 825 // // For i386: 826 // // DW_CFA_val_expression where: 827 // // eip = DW_OP_breg6(+28), DW_OP_deref, DW_OP_dup, DW_OP_plus_uconst(0x34), 828 // // DW_OP_deref, DW_OP_swap, DW_OP_plus_uconst(0), DW_OP_deref, 829 // // DW_OP_dup, DW_OP_lit3, DW_OP_ne, DW_OP_swap, DW_OP_lit4, DW_OP_ne, 830 // // DW_OP_and, DW_OP_plus 831 // // This basically does a: 832 // // eip = ucontenxt.mcontext32->gpr.eip; 833 // // if (ucontenxt.mcontext32->exc.trapno != 3 && ucontenxt.mcontext32->exc.trapno != 4) 834 // // eip++; 835 // // 836 // // For x86_64: 837 // // DW_CFA_val_expression where: 838 // // rip = DW_OP_breg3(+48), DW_OP_deref, DW_OP_dup, DW_OP_plus_uconst(0x90), DW_OP_deref, 839 // // DW_OP_swap, DW_OP_plus_uconst(0), DW_OP_deref_size(4), DW_OP_dup, DW_OP_lit3, 840 // // DW_OP_ne, DW_OP_swap, DW_OP_lit4, DW_OP_ne, DW_OP_and, DW_OP_plus 841 // // This basically does a: 842 // // rip = ucontenxt.mcontext64->gpr.rip; 843 // // if (ucontenxt.mcontext64->exc.trapno != 3 && ucontenxt.mcontext64->exc.trapno != 4) 844 // // rip++; 845 // // The trap comparisons and increments are not needed as it hoses up the unwound PC which 846 // // is expected to point at least past the instruction that causes the fault/trap. So we 847 // // take it out by trimming the expression right at the first "DW_OP_swap" opcodes 848 // if (block_data != NULL && thread->GetPCRegNum(Thread::GCC) == reg_num) 849 // { 850 // if (thread->Is64Bit()) 851 // { 852 // if (block_len > 9 && block_data[8] == DW_OP_swap && block_data[9] == DW_OP_plus_uconst) 853 // block_len = 8; 854 // } 855 // else 856 // { 857 // if (block_len > 8 && block_data[7] == DW_OP_swap && block_data[8] == DW_OP_plus_uconst) 858 // block_len = 7; 859 // } 860 // } 861 //#endif 862 reg_location.SetIsDWARFExpression(block_data, block_len); 863 row->SetRegisterInfo (reg_num, reg_location); 864 } 865 break; 866 867 case DW_CFA_val_offset : // 0x14 868 case DW_CFA_val_offset_sf : // 0x15 869 default: 870 break; 871 } 872 } 873 } 874 unwind_plan.AppendRow(row); 875 876 return true; 877 } 878