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 (cie_id == 0 || cie_id == UINT32_MAX || len == 0) 369 { 370 m_cie_map[current_entry] = ParseCIE (current_entry); 371 offset = next_entry; 372 continue; 373 } 374 375 const CIE *cie = GetCIE (cie_offset); 376 if (cie) 377 { 378 const lldb::addr_t pc_rel_addr = m_section_sp->GetFileAddress(); 379 const lldb::addr_t text_addr = LLDB_INVALID_ADDRESS; 380 const lldb::addr_t data_addr = LLDB_INVALID_ADDRESS; 381 382 lldb::addr_t addr = m_cfi_data.GetGNUEHPointer(&offset, cie->ptr_encoding, pc_rel_addr, text_addr, data_addr); 383 lldb::addr_t length = m_cfi_data.GetGNUEHPointer(&offset, cie->ptr_encoding & DW_EH_PE_MASK_ENCODING, pc_rel_addr, text_addr, data_addr); 384 FDEEntryMap::Entry fde (addr, length, current_entry); 385 m_fde_index.Append(fde); 386 } 387 else 388 { 389 Host::SystemLog (Host::eSystemLogError, 390 "error: unable to find CIE at 0x%8.8x for cie_id = 0x%8.8x for entry at 0x%8.8x.\n", 391 cie_offset, 392 cie_id, 393 current_entry); 394 } 395 offset = next_entry; 396 } 397 m_fde_index.Sort(); 398 m_fde_index_initialized = true; 399 } 400 401 bool 402 DWARFCallFrameInfo::FDEToUnwindPlan (dw_offset_t dwarf_offset, Address startaddr, UnwindPlan& unwind_plan) 403 { 404 lldb::offset_t offset = dwarf_offset; 405 lldb::offset_t current_entry = offset; 406 407 if (m_section_sp.get() == nullptr || m_section_sp->IsEncrypted()) 408 return false; 409 410 if (m_cfi_data_initialized == false) 411 GetCFIData(); 412 413 uint32_t length = m_cfi_data.GetU32 (&offset); 414 dw_offset_t cie_offset; 415 bool is_64bit = (length == UINT32_MAX); 416 if (is_64bit) { 417 length = m_cfi_data.GetU64 (&offset); 418 cie_offset = m_cfi_data.GetU64 (&offset); 419 } else { 420 cie_offset = m_cfi_data.GetU32 (&offset); 421 } 422 423 assert (cie_offset != 0 && cie_offset != UINT32_MAX); 424 425 // Translate the CIE_id from the eh_frame format, which 426 // is relative to the FDE offset, into a __eh_frame section 427 // offset 428 if (m_is_eh_frame) 429 { 430 unwind_plan.SetSourceName ("eh_frame CFI"); 431 cie_offset = current_entry + (is_64bit ? 12 : 4) - cie_offset; 432 unwind_plan.SetUnwindPlanValidAtAllInstructions (eLazyBoolNo); 433 } 434 else 435 { 436 unwind_plan.SetSourceName ("DWARF CFI"); 437 // In theory the debug_frame info should be valid at all call sites 438 // ("asynchronous unwind info" as it is sometimes called) but in practice 439 // gcc et al all emit call frame info for the prologue and call sites, but 440 // not for the epilogue or all the other locations during the function reliably. 441 unwind_plan.SetUnwindPlanValidAtAllInstructions (eLazyBoolNo); 442 } 443 unwind_plan.SetSourcedFromCompiler (eLazyBoolYes); 444 445 const CIE *cie = GetCIE (cie_offset); 446 assert (cie != nullptr); 447 448 const dw_offset_t end_offset = current_entry + length + (is_64bit ? 12 : 4); 449 450 const lldb::addr_t pc_rel_addr = m_section_sp->GetFileAddress(); 451 const lldb::addr_t text_addr = LLDB_INVALID_ADDRESS; 452 const lldb::addr_t data_addr = LLDB_INVALID_ADDRESS; 453 lldb::addr_t range_base = m_cfi_data.GetGNUEHPointer(&offset, cie->ptr_encoding, pc_rel_addr, text_addr, data_addr); 454 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); 455 AddressRange range (range_base, m_objfile.GetAddressByteSize(), m_objfile.GetSectionList()); 456 range.SetByteSize (range_len); 457 458 addr_t lsda_data_file_address = LLDB_INVALID_ADDRESS; 459 460 if (cie->augmentation[0] == 'z') 461 { 462 uint32_t aug_data_len = (uint32_t)m_cfi_data.GetULEB128(&offset); 463 if (aug_data_len != 0 && cie->lsda_addr_encoding != DW_EH_PE_omit) 464 { 465 offset_t saved_offset = offset; 466 lsda_data_file_address = m_cfi_data.GetGNUEHPointer(&offset, cie->lsda_addr_encoding, pc_rel_addr, text_addr, data_addr); 467 if (offset - saved_offset != aug_data_len) 468 { 469 // There is more in the augmentation region than we know how to process; 470 // don't read anything. 471 lsda_data_file_address = LLDB_INVALID_ADDRESS; 472 } 473 offset = saved_offset; 474 } 475 offset += aug_data_len; 476 } 477 Address lsda_data; 478 Address personality_function_ptr; 479 480 if (lsda_data_file_address != LLDB_INVALID_ADDRESS && cie->personality_loc != LLDB_INVALID_ADDRESS) 481 { 482 m_objfile.GetModule()->ResolveFileAddress (lsda_data_file_address, lsda_data); 483 m_objfile.GetModule()->ResolveFileAddress (cie->personality_loc, personality_function_ptr); 484 } 485 486 if (lsda_data.IsValid() && personality_function_ptr.IsValid()) 487 { 488 unwind_plan.SetLSDAAddress (lsda_data); 489 unwind_plan.SetPersonalityFunctionPtr (personality_function_ptr); 490 } 491 492 uint32_t reg_num = 0; 493 int32_t op_offset = 0; 494 uint32_t code_align = cie->code_align; 495 int32_t data_align = cie->data_align; 496 497 unwind_plan.SetPlanValidAddressRange (range); 498 UnwindPlan::Row *cie_initial_row = new UnwindPlan::Row; 499 *cie_initial_row = cie->initial_row; 500 UnwindPlan::RowSP row(cie_initial_row); 501 502 unwind_plan.SetRegisterKind (m_reg_kind); 503 unwind_plan.SetReturnAddressRegister (cie->return_addr_reg_num); 504 505 std::vector<UnwindPlan::RowSP> stack; 506 507 UnwindPlan::Row::RegisterLocation reg_location; 508 while (m_cfi_data.ValidOffset(offset) && offset < end_offset) 509 { 510 uint8_t inst = m_cfi_data.GetU8(&offset); 511 uint8_t primary_opcode = inst & 0xC0; 512 uint8_t extended_opcode = inst & 0x3F; 513 514 if (primary_opcode) 515 { 516 switch (primary_opcode) 517 { 518 case DW_CFA_advance_loc : // (Row Creation Instruction) 519 { // 0x40 - high 2 bits are 0x1, lower 6 bits are delta 520 // takes a single argument that represents a constant delta. The 521 // required action is to create a new table row with a location 522 // value that is computed by taking the current entry's location 523 // value and adding (delta * code_align). All other 524 // values in the new row are initially identical to the current row. 525 unwind_plan.AppendRow(row); 526 UnwindPlan::Row *newrow = new UnwindPlan::Row; 527 *newrow = *row.get(); 528 row.reset (newrow); 529 row->SlideOffset(extended_opcode * code_align); 530 } 531 break; 532 533 case DW_CFA_offset : 534 { // 0x80 - high 2 bits are 0x2, lower 6 bits are register 535 // takes two arguments: an unsigned LEB128 constant representing a 536 // factored offset and a register number. The required action is to 537 // change the rule for the register indicated by the register number 538 // to be an offset(N) rule with a value of 539 // (N = factored offset * data_align). 540 reg_num = extended_opcode; 541 op_offset = (int32_t)m_cfi_data.GetULEB128(&offset) * data_align; 542 reg_location.SetAtCFAPlusOffset(op_offset); 543 row->SetRegisterInfo (reg_num, reg_location); 544 } 545 break; 546 547 case DW_CFA_restore : 548 { // 0xC0 - high 2 bits are 0x3, lower 6 bits are register 549 // takes a single argument that represents a register number. The 550 // required action is to change the rule for the indicated register 551 // to the rule assigned it by the initial_instructions in the CIE. 552 reg_num = extended_opcode; 553 // We only keep enough register locations around to 554 // unwind what is in our thread, and these are organized 555 // by the register index in that state, so we need to convert our 556 // GCC register number from the EH frame info, to a register index 557 558 if (unwind_plan.IsValidRowIndex(0) && unwind_plan.GetRowAtIndex(0)->GetRegisterInfo(reg_num, reg_location)) 559 row->SetRegisterInfo (reg_num, reg_location); 560 } 561 break; 562 } 563 } 564 else 565 { 566 switch (extended_opcode) 567 { 568 case DW_CFA_nop : // 0x0 569 break; 570 571 case DW_CFA_set_loc : // 0x1 (Row Creation Instruction) 572 { 573 // DW_CFA_set_loc takes a single argument that represents an address. 574 // The required action is to create a new table row using the 575 // specified address as the location. All other values in the new row 576 // are initially identical to the current row. The new location value 577 // should always be greater than the current one. 578 unwind_plan.AppendRow(row); 579 UnwindPlan::Row *newrow = new UnwindPlan::Row; 580 *newrow = *row.get(); 581 row.reset (newrow); 582 row->SetOffset(m_cfi_data.GetPointer(&offset) - startaddr.GetFileAddress()); 583 } 584 break; 585 586 case DW_CFA_advance_loc1 : // 0x2 (Row Creation Instruction) 587 { 588 // takes a single uword argument that represents a constant delta. 589 // This instruction is identical to DW_CFA_advance_loc except for the 590 // encoding and size of the delta argument. 591 unwind_plan.AppendRow(row); 592 UnwindPlan::Row *newrow = new UnwindPlan::Row; 593 *newrow = *row.get(); 594 row.reset (newrow); 595 row->SlideOffset (m_cfi_data.GetU8(&offset) * code_align); 596 } 597 break; 598 599 case DW_CFA_advance_loc2 : // 0x3 (Row Creation Instruction) 600 { 601 // takes a single uword argument that represents a constant delta. 602 // This instruction is identical to DW_CFA_advance_loc except for the 603 // encoding and size of the delta argument. 604 unwind_plan.AppendRow(row); 605 UnwindPlan::Row *newrow = new UnwindPlan::Row; 606 *newrow = *row.get(); 607 row.reset (newrow); 608 row->SlideOffset (m_cfi_data.GetU16(&offset) * code_align); 609 } 610 break; 611 612 case DW_CFA_advance_loc4 : // 0x4 (Row Creation Instruction) 613 { 614 // takes a single uword argument that represents a constant delta. 615 // This instruction is identical to DW_CFA_advance_loc except for the 616 // encoding and size of the delta argument. 617 unwind_plan.AppendRow(row); 618 UnwindPlan::Row *newrow = new UnwindPlan::Row; 619 *newrow = *row.get(); 620 row.reset (newrow); 621 row->SlideOffset (m_cfi_data.GetU32(&offset) * code_align); 622 } 623 break; 624 625 case DW_CFA_offset_extended : // 0x5 626 { 627 // takes two unsigned LEB128 arguments representing a register number 628 // and a factored offset. This instruction is identical to DW_CFA_offset 629 // except for the encoding and size of the register argument. 630 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 631 op_offset = (int32_t)m_cfi_data.GetULEB128(&offset) * data_align; 632 reg_location.SetAtCFAPlusOffset(op_offset); 633 row->SetRegisterInfo (reg_num, reg_location); 634 } 635 break; 636 637 case DW_CFA_restore_extended : // 0x6 638 { 639 // takes a single unsigned LEB128 argument that represents a register 640 // number. This instruction is identical to DW_CFA_restore except for 641 // the encoding and size of the register argument. 642 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 643 if (unwind_plan.IsValidRowIndex(0) && unwind_plan.GetRowAtIndex(0)->GetRegisterInfo(reg_num, reg_location)) 644 row->SetRegisterInfo (reg_num, reg_location); 645 } 646 break; 647 648 case DW_CFA_undefined : // 0x7 649 { 650 // takes a single unsigned LEB128 argument that represents a register 651 // number. The required action is to set the rule for the specified 652 // register to undefined. 653 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 654 reg_location.SetUndefined(); 655 row->SetRegisterInfo (reg_num, reg_location); 656 } 657 break; 658 659 case DW_CFA_same_value : // 0x8 660 { 661 // takes a single unsigned LEB128 argument that represents a register 662 // number. The required action is to set the rule for the specified 663 // register to same value. 664 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 665 reg_location.SetSame(); 666 row->SetRegisterInfo (reg_num, reg_location); 667 } 668 break; 669 670 case DW_CFA_register : // 0x9 671 { 672 // takes two unsigned LEB128 arguments representing register numbers. 673 // The required action is to set the rule for the first register to be 674 // the second register. 675 676 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 677 uint32_t other_reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 678 reg_location.SetInRegister(other_reg_num); 679 row->SetRegisterInfo (reg_num, reg_location); 680 } 681 break; 682 683 case DW_CFA_remember_state : // 0xA 684 { 685 // These instructions define a stack of information. Encountering the 686 // DW_CFA_remember_state instruction means to save the rules for every 687 // register on the current row on the stack. Encountering the 688 // DW_CFA_restore_state instruction means to pop the set of rules off 689 // the stack and place them in the current row. (This operation is 690 // useful for compilers that move epilogue code into the body of a 691 // function.) 692 stack.push_back (row); 693 UnwindPlan::Row *newrow = new UnwindPlan::Row; 694 *newrow = *row.get(); 695 row.reset (newrow); 696 } 697 break; 698 699 case DW_CFA_restore_state : // 0xB 700 // These instructions define a stack of information. Encountering the 701 // DW_CFA_remember_state instruction means to save the rules for every 702 // register on the current row on the stack. Encountering the 703 // DW_CFA_restore_state instruction means to pop the set of rules off 704 // the stack and place them in the current row. (This operation is 705 // useful for compilers that move epilogue code into the body of a 706 // function.) 707 { 708 row = stack.back (); 709 stack.pop_back (); 710 } 711 break; 712 713 case DW_CFA_def_cfa : // 0xC (CFA Definition Instruction) 714 { 715 // Takes two unsigned LEB128 operands representing a register 716 // number and a (non-factored) offset. The required action 717 // is to define the current CFA rule to use the provided 718 // register and offset. 719 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 720 op_offset = (int32_t)m_cfi_data.GetULEB128(&offset); 721 row->GetCFAValue().SetIsRegisterPlusOffset (reg_num, op_offset); 722 } 723 break; 724 725 case DW_CFA_def_cfa_register : // 0xD (CFA Definition Instruction) 726 { 727 // takes a single unsigned LEB128 argument representing a register 728 // number. The required action is to define the current CFA rule to 729 // use the provided register (but to keep the old offset). 730 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 731 row->GetCFAValue().SetIsRegisterPlusOffset (reg_num, 732 row->GetCFAValue().GetOffset()); 733 } 734 break; 735 736 case DW_CFA_def_cfa_offset : // 0xE (CFA Definition Instruction) 737 { 738 // Takes a single unsigned LEB128 operand representing a 739 // (non-factored) offset. The required action is to define 740 // the current CFA rule to use the provided offset (but 741 // to keep the old register). 742 op_offset = (int32_t)m_cfi_data.GetULEB128(&offset); 743 row->GetCFAValue().SetIsRegisterPlusOffset ( 744 row->GetCFAValue().GetRegisterNumber(), 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 const uint8_t *block_data = 752 static_cast<const uint8_t *>(m_cfi_data.GetData(&offset, block_len)); 753 row->GetCFAValue().SetIsDWARFExpression(block_data, block_len); 754 } 755 break; 756 757 case DW_CFA_expression : // 0x10 758 { 759 // Takes two operands: an unsigned LEB128 value representing 760 // a register number, and a DW_FORM_block value representing a DWARF 761 // expression. The required action is to change the rule for the 762 // register indicated by the register number to be an expression(E) 763 // rule where E is the DWARF expression. That is, the DWARF 764 // expression computes the address. The value of the CFA is 765 // pushed on the DWARF evaluation stack prior to execution of 766 // the DWARF expression. 767 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 768 uint32_t block_len = (uint32_t)m_cfi_data.GetULEB128(&offset); 769 const uint8_t *block_data = (uint8_t *)m_cfi_data.GetData(&offset, block_len); 770 771 reg_location.SetAtDWARFExpression(block_data, block_len); 772 row->SetRegisterInfo (reg_num, reg_location); 773 } 774 break; 775 776 case DW_CFA_offset_extended_sf : // 0x11 777 { 778 // takes two operands: an unsigned LEB128 value representing a 779 // register number and a signed LEB128 factored offset. This 780 // instruction is identical to DW_CFA_offset_extended except 781 //that the second operand is signed and factored. 782 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 783 op_offset = (int32_t)m_cfi_data.GetSLEB128(&offset) * data_align; 784 reg_location.SetAtCFAPlusOffset(op_offset); 785 row->SetRegisterInfo (reg_num, reg_location); 786 } 787 break; 788 789 case DW_CFA_def_cfa_sf : // 0x12 (CFA Definition Instruction) 790 { 791 // Takes two operands: an unsigned LEB128 value representing 792 // a register number and a signed LEB128 factored offset. 793 // This instruction is identical to DW_CFA_def_cfa except 794 // that the second operand is signed and factored. 795 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 796 op_offset = (int32_t)m_cfi_data.GetSLEB128(&offset) * data_align; 797 row->GetCFAValue().SetIsRegisterPlusOffset (reg_num, op_offset); 798 } 799 break; 800 801 case DW_CFA_def_cfa_offset_sf : // 0x13 (CFA Definition Instruction) 802 { 803 // takes a signed LEB128 operand representing a factored 804 // offset. This instruction is identical to DW_CFA_def_cfa_offset 805 // except that the operand is signed and factored. 806 op_offset = (int32_t)m_cfi_data.GetSLEB128(&offset) * data_align; 807 row->GetCFAValue().SetIsRegisterPlusOffset ( 808 row->GetCFAValue().GetRegisterNumber(), op_offset); 809 } 810 break; 811 812 case DW_CFA_val_expression : // 0x16 813 { 814 // takes two operands: an unsigned LEB128 value representing a register 815 // number, and a DW_FORM_block value representing a DWARF expression. 816 // The required action is to change the rule for the register indicated 817 // by the register number to be a val_expression(E) rule where E is the 818 // DWARF expression. That is, the DWARF expression computes the value of 819 // the given register. The value of the CFA is pushed on the DWARF 820 // evaluation stack prior to execution of the DWARF expression. 821 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 822 uint32_t block_len = (uint32_t)m_cfi_data.GetULEB128(&offset); 823 const uint8_t* block_data = (uint8_t*)m_cfi_data.GetData(&offset, block_len); 824 //#if defined(__i386__) || defined(__x86_64__) 825 // // The EH frame info for EIP and RIP contains code that looks for traps to 826 // // be a specific type and increments the PC. 827 // // For i386: 828 // // DW_CFA_val_expression where: 829 // // eip = DW_OP_breg6(+28), DW_OP_deref, DW_OP_dup, DW_OP_plus_uconst(0x34), 830 // // DW_OP_deref, DW_OP_swap, DW_OP_plus_uconst(0), DW_OP_deref, 831 // // DW_OP_dup, DW_OP_lit3, DW_OP_ne, DW_OP_swap, DW_OP_lit4, DW_OP_ne, 832 // // DW_OP_and, DW_OP_plus 833 // // This basically does a: 834 // // eip = ucontenxt.mcontext32->gpr.eip; 835 // // if (ucontenxt.mcontext32->exc.trapno != 3 && ucontenxt.mcontext32->exc.trapno != 4) 836 // // eip++; 837 // // 838 // // For x86_64: 839 // // DW_CFA_val_expression where: 840 // // rip = DW_OP_breg3(+48), DW_OP_deref, DW_OP_dup, DW_OP_plus_uconst(0x90), DW_OP_deref, 841 // // DW_OP_swap, DW_OP_plus_uconst(0), DW_OP_deref_size(4), DW_OP_dup, DW_OP_lit3, 842 // // DW_OP_ne, DW_OP_swap, DW_OP_lit4, DW_OP_ne, DW_OP_and, DW_OP_plus 843 // // This basically does a: 844 // // rip = ucontenxt.mcontext64->gpr.rip; 845 // // if (ucontenxt.mcontext64->exc.trapno != 3 && ucontenxt.mcontext64->exc.trapno != 4) 846 // // rip++; 847 // // The trap comparisons and increments are not needed as it hoses up the unwound PC which 848 // // is expected to point at least past the instruction that causes the fault/trap. So we 849 // // take it out by trimming the expression right at the first "DW_OP_swap" opcodes 850 // if (block_data != NULL && thread->GetPCRegNum(Thread::GCC) == reg_num) 851 // { 852 // if (thread->Is64Bit()) 853 // { 854 // if (block_len > 9 && block_data[8] == DW_OP_swap && block_data[9] == DW_OP_plus_uconst) 855 // block_len = 8; 856 // } 857 // else 858 // { 859 // if (block_len > 8 && block_data[7] == DW_OP_swap && block_data[8] == DW_OP_plus_uconst) 860 // block_len = 7; 861 // } 862 // } 863 //#endif 864 reg_location.SetIsDWARFExpression(block_data, block_len); 865 row->SetRegisterInfo (reg_num, reg_location); 866 } 867 break; 868 869 case DW_CFA_val_offset : // 0x14 870 case DW_CFA_val_offset_sf : // 0x15 871 default: 872 break; 873 } 874 } 875 } 876 unwind_plan.AppendRow(row); 877 878 return true; 879 } 880