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 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_sp-> 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 uint8_t arg_ptr_encoding = m_cfi_data.GetU8(&offset); 234 m_cfi_data.GetGNUEHPointer(&offset, arg_ptr_encoding, LLDB_INVALID_ADDRESS, LLDB_INVALID_ADDRESS, LLDB_INVALID_ADDRESS); 235 } 236 break; 237 238 case 'R': 239 // A 'R' may be present at any position after the 240 // first character of the string. The Augmentation 241 // Data shall include a 1 byte argument that 242 // represents the pointer encoding for the address 243 // pointers used in the FDE. 244 // Example: 0x1B == DW_EH_PE_pcrel | DW_EH_PE_sdata4 245 cie_sp->ptr_encoding = m_cfi_data.GetU8(&offset); 246 break; 247 } 248 } 249 } 250 else if (strcmp(cie_sp->augmentation, "eh") == 0) 251 { 252 // If the Augmentation string has the value "eh", then 253 // the EH Data field shall be present 254 } 255 256 // Set the offset to be the end of the augmentation data just in case 257 // we didn't understand any of the data. 258 offset = (uint32_t)aug_data_end; 259 } 260 261 if (end_offset > offset) 262 { 263 cie_sp->inst_offset = offset; 264 cie_sp->inst_length = end_offset - offset; 265 } 266 while (offset < end_offset) 267 { 268 uint8_t inst = m_cfi_data.GetU8(&offset); 269 uint8_t primary_opcode = inst & 0xC0; 270 uint8_t extended_opcode = inst & 0x3F; 271 272 if (extended_opcode == DW_CFA_def_cfa) 273 { 274 // Takes two unsigned LEB128 operands representing a register 275 // number and a (non-factored) offset. The required action 276 // is to define the current CFA rule to use the provided 277 // register and offset. 278 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 279 int op_offset = (int32_t)m_cfi_data.GetULEB128(&offset); 280 cie_sp->initial_row.SetCFARegister (reg_num); 281 cie_sp->initial_row.SetCFAOffset (op_offset); 282 continue; 283 } 284 if (primary_opcode == DW_CFA_offset) 285 { 286 // 0x80 - high 2 bits are 0x2, lower 6 bits are register. 287 // Takes two arguments: an unsigned LEB128 constant representing a 288 // factored offset and a register number. The required action is to 289 // change the rule for the register indicated by the register number 290 // to be an offset(N) rule with a value of 291 // (N = factored offset * data_align). 292 uint32_t reg_num = extended_opcode; 293 int op_offset = (int32_t)m_cfi_data.GetULEB128(&offset) * cie_sp->data_align; 294 UnwindPlan::Row::RegisterLocation reg_location; 295 reg_location.SetAtCFAPlusOffset(op_offset); 296 cie_sp->initial_row.SetRegisterInfo (reg_num, reg_location); 297 continue; 298 } 299 if (extended_opcode == DW_CFA_nop) 300 { 301 continue; 302 } 303 break; // Stop if we hit an unrecognized opcode 304 } 305 } 306 307 return cie_sp; 308 } 309 310 void 311 DWARFCallFrameInfo::GetCFIData() 312 { 313 if (m_cfi_data_initialized == false) 314 { 315 Log *log(GetLogIfAllCategoriesSet (LIBLLDB_LOG_UNWIND)); 316 if (log) 317 m_objfile.GetModule()->LogMessage(log, "Reading EH frame info"); 318 m_objfile.ReadSectionData (m_section_sp.get(), m_cfi_data); 319 m_cfi_data_initialized = true; 320 } 321 } 322 // Scan through the eh_frame or debug_frame section looking for FDEs and noting the start/end addresses 323 // of the functions and a pointer back to the function's FDE for later expansion. 324 // Internalize CIEs as we come across them. 325 326 void 327 DWARFCallFrameInfo::GetFDEIndex () 328 { 329 if (m_section_sp.get() == nullptr || m_section_sp->IsEncrypted()) 330 return; 331 332 if (m_fde_index_initialized) 333 return; 334 335 Mutex::Locker locker(m_fde_index_mutex); 336 337 if (m_fde_index_initialized) // if two threads hit the locker 338 return; 339 340 Timer scoped_timer (__PRETTY_FUNCTION__, "%s - %s", __PRETTY_FUNCTION__, m_objfile.GetFileSpec().GetFilename().AsCString("")); 341 342 lldb::offset_t offset = 0; 343 if (m_cfi_data_initialized == false) 344 GetCFIData(); 345 while (m_cfi_data.ValidOffsetForDataOfSize (offset, 8)) 346 { 347 const dw_offset_t current_entry = offset; 348 dw_offset_t cie_id, next_entry, cie_offset; 349 uint32_t len = m_cfi_data.GetU32 (&offset); 350 bool is_64bit = (len == UINT32_MAX); 351 if (is_64bit) { 352 len = m_cfi_data.GetU64 (&offset); 353 cie_id = m_cfi_data.GetU64 (&offset); 354 next_entry = current_entry + len + 12; 355 cie_offset = current_entry + 12 - cie_id; 356 } else { 357 cie_id = m_cfi_data.GetU32 (&offset); 358 next_entry = current_entry + len + 4; 359 cie_offset = current_entry + 4 - cie_id; 360 } 361 362 if (cie_id == 0 || cie_id == UINT32_MAX || len == 0) 363 { 364 m_cie_map[current_entry] = ParseCIE (current_entry); 365 offset = next_entry; 366 continue; 367 } 368 369 const CIE *cie = GetCIE (cie_offset); 370 if (cie) 371 { 372 const lldb::addr_t pc_rel_addr = m_section_sp->GetFileAddress(); 373 const lldb::addr_t text_addr = LLDB_INVALID_ADDRESS; 374 const lldb::addr_t data_addr = LLDB_INVALID_ADDRESS; 375 376 lldb::addr_t addr = m_cfi_data.GetGNUEHPointer(&offset, cie->ptr_encoding, pc_rel_addr, text_addr, data_addr); 377 lldb::addr_t length = m_cfi_data.GetGNUEHPointer(&offset, cie->ptr_encoding & DW_EH_PE_MASK_ENCODING, pc_rel_addr, text_addr, data_addr); 378 FDEEntryMap::Entry fde (addr, length, current_entry); 379 m_fde_index.Append(fde); 380 } 381 else 382 { 383 Host::SystemLog (Host::eSystemLogError, 384 "error: unable to find CIE at 0x%8.8x for cie_id = 0x%8.8x for entry at 0x%8.8x.\n", 385 cie_offset, 386 cie_id, 387 current_entry); 388 } 389 offset = next_entry; 390 } 391 m_fde_index.Sort(); 392 m_fde_index_initialized = true; 393 } 394 395 bool 396 DWARFCallFrameInfo::FDEToUnwindPlan (dw_offset_t dwarf_offset, Address startaddr, UnwindPlan& unwind_plan) 397 { 398 lldb::offset_t offset = dwarf_offset; 399 lldb::offset_t current_entry = offset; 400 401 if (m_section_sp.get() == nullptr || m_section_sp->IsEncrypted()) 402 return false; 403 404 if (m_cfi_data_initialized == false) 405 GetCFIData(); 406 407 uint32_t length = m_cfi_data.GetU32 (&offset); 408 dw_offset_t cie_offset; 409 bool is_64bit = (length == UINT32_MAX); 410 if (is_64bit) { 411 length = m_cfi_data.GetU64 (&offset); 412 cie_offset = m_cfi_data.GetU64 (&offset); 413 } else { 414 cie_offset = m_cfi_data.GetU32 (&offset); 415 } 416 417 assert (cie_offset != 0 && cie_offset != UINT32_MAX); 418 419 // Translate the CIE_id from the eh_frame format, which 420 // is relative to the FDE offset, into a __eh_frame section 421 // offset 422 if (m_is_eh_frame) 423 { 424 unwind_plan.SetSourceName ("eh_frame CFI"); 425 cie_offset = current_entry + (is_64bit ? 12 : 4) - cie_offset; 426 unwind_plan.SetUnwindPlanValidAtAllInstructions (eLazyBoolNo); 427 } 428 else 429 { 430 unwind_plan.SetSourceName ("DWARF CFI"); 431 // In theory the debug_frame info should be valid at all call sites 432 // ("asynchronous unwind info" as it is sometimes called) but in practice 433 // gcc et al all emit call frame info for the prologue and call sites, but 434 // not for the epilogue or all the other locations during the function reliably. 435 unwind_plan.SetUnwindPlanValidAtAllInstructions (eLazyBoolNo); 436 } 437 unwind_plan.SetSourcedFromCompiler (eLazyBoolYes); 438 439 const CIE *cie = GetCIE (cie_offset); 440 assert (cie != nullptr); 441 442 const dw_offset_t end_offset = current_entry + length + (is_64bit ? 12 : 4); 443 444 const lldb::addr_t pc_rel_addr = m_section_sp->GetFileAddress(); 445 const lldb::addr_t text_addr = LLDB_INVALID_ADDRESS; 446 const lldb::addr_t data_addr = LLDB_INVALID_ADDRESS; 447 lldb::addr_t range_base = m_cfi_data.GetGNUEHPointer(&offset, cie->ptr_encoding, pc_rel_addr, text_addr, data_addr); 448 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); 449 AddressRange range (range_base, m_objfile.GetAddressByteSize(), m_objfile.GetSectionList()); 450 range.SetByteSize (range_len); 451 452 if (cie->augmentation[0] == 'z') 453 { 454 uint32_t aug_data_len = (uint32_t)m_cfi_data.GetULEB128(&offset); 455 offset += aug_data_len; 456 } 457 458 uint32_t reg_num = 0; 459 int32_t op_offset = 0; 460 uint32_t code_align = cie->code_align; 461 int32_t data_align = cie->data_align; 462 463 unwind_plan.SetPlanValidAddressRange (range); 464 UnwindPlan::Row *cie_initial_row = new UnwindPlan::Row; 465 *cie_initial_row = cie->initial_row; 466 UnwindPlan::RowSP row(cie_initial_row); 467 468 unwind_plan.SetRegisterKind (m_reg_kind); 469 unwind_plan.SetReturnAddressRegister (cie->return_addr_reg_num); 470 471 std::vector<UnwindPlan::RowSP> stack; 472 473 UnwindPlan::Row::RegisterLocation reg_location; 474 while (m_cfi_data.ValidOffset(offset) && offset < end_offset) 475 { 476 uint8_t inst = m_cfi_data.GetU8(&offset); 477 uint8_t primary_opcode = inst & 0xC0; 478 uint8_t extended_opcode = inst & 0x3F; 479 480 if (primary_opcode) 481 { 482 switch (primary_opcode) 483 { 484 case DW_CFA_advance_loc : // (Row Creation Instruction) 485 { // 0x40 - high 2 bits are 0x1, lower 6 bits are delta 486 // takes a single argument that represents a constant delta. The 487 // required action is to create a new table row with a location 488 // value that is computed by taking the current entry's location 489 // value and adding (delta * code_align). All other 490 // values in the new row are initially identical to the current row. 491 unwind_plan.AppendRow(row); 492 UnwindPlan::Row *newrow = new UnwindPlan::Row; 493 *newrow = *row.get(); 494 row.reset (newrow); 495 row->SlideOffset(extended_opcode * code_align); 496 } 497 break; 498 499 case DW_CFA_offset : 500 { // 0x80 - high 2 bits are 0x2, lower 6 bits are register 501 // takes two arguments: an unsigned LEB128 constant representing a 502 // factored offset and a register number. The required action is to 503 // change the rule for the register indicated by the register number 504 // to be an offset(N) rule with a value of 505 // (N = factored offset * data_align). 506 reg_num = extended_opcode; 507 op_offset = (int32_t)m_cfi_data.GetULEB128(&offset) * data_align; 508 reg_location.SetAtCFAPlusOffset(op_offset); 509 row->SetRegisterInfo (reg_num, reg_location); 510 } 511 break; 512 513 case DW_CFA_restore : 514 { // 0xC0 - high 2 bits are 0x3, lower 6 bits are register 515 // takes a single argument that represents a register number. The 516 // required action is to change the rule for the indicated register 517 // to the rule assigned it by the initial_instructions in the CIE. 518 reg_num = extended_opcode; 519 // We only keep enough register locations around to 520 // unwind what is in our thread, and these are organized 521 // by the register index in that state, so we need to convert our 522 // GCC register number from the EH frame info, to a register index 523 524 if (unwind_plan.IsValidRowIndex(0) && unwind_plan.GetRowAtIndex(0)->GetRegisterInfo(reg_num, reg_location)) 525 row->SetRegisterInfo (reg_num, reg_location); 526 } 527 break; 528 } 529 } 530 else 531 { 532 switch (extended_opcode) 533 { 534 case DW_CFA_nop : // 0x0 535 break; 536 537 case DW_CFA_set_loc : // 0x1 (Row Creation Instruction) 538 { 539 // DW_CFA_set_loc takes a single argument that represents an address. 540 // The required action is to create a new table row using the 541 // specified address as the location. All other values in the new row 542 // are initially identical to the current row. The new location value 543 // should always be greater than the current one. 544 unwind_plan.AppendRow(row); 545 UnwindPlan::Row *newrow = new UnwindPlan::Row; 546 *newrow = *row.get(); 547 row.reset (newrow); 548 row->SetOffset(m_cfi_data.GetPointer(&offset) - startaddr.GetFileAddress()); 549 } 550 break; 551 552 case DW_CFA_advance_loc1 : // 0x2 (Row Creation Instruction) 553 { 554 // takes a single uword argument that represents a constant delta. 555 // This instruction is identical to DW_CFA_advance_loc except for the 556 // encoding and size of the delta argument. 557 unwind_plan.AppendRow(row); 558 UnwindPlan::Row *newrow = new UnwindPlan::Row; 559 *newrow = *row.get(); 560 row.reset (newrow); 561 row->SlideOffset (m_cfi_data.GetU8(&offset) * code_align); 562 } 563 break; 564 565 case DW_CFA_advance_loc2 : // 0x3 (Row Creation Instruction) 566 { 567 // takes a single uword argument that represents a constant delta. 568 // This instruction is identical to DW_CFA_advance_loc except for the 569 // encoding and size of the delta argument. 570 unwind_plan.AppendRow(row); 571 UnwindPlan::Row *newrow = new UnwindPlan::Row; 572 *newrow = *row.get(); 573 row.reset (newrow); 574 row->SlideOffset (m_cfi_data.GetU16(&offset) * code_align); 575 } 576 break; 577 578 case DW_CFA_advance_loc4 : // 0x4 (Row Creation Instruction) 579 { 580 // takes a single uword argument that represents a constant delta. 581 // This instruction is identical to DW_CFA_advance_loc except for the 582 // encoding and size of the delta argument. 583 unwind_plan.AppendRow(row); 584 UnwindPlan::Row *newrow = new UnwindPlan::Row; 585 *newrow = *row.get(); 586 row.reset (newrow); 587 row->SlideOffset (m_cfi_data.GetU32(&offset) * code_align); 588 } 589 break; 590 591 case DW_CFA_offset_extended : // 0x5 592 { 593 // takes two unsigned LEB128 arguments representing a register number 594 // and a factored offset. This instruction is identical to DW_CFA_offset 595 // except for the encoding and size of the register argument. 596 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 597 op_offset = (int32_t)m_cfi_data.GetULEB128(&offset) * data_align; 598 reg_location.SetAtCFAPlusOffset(op_offset); 599 row->SetRegisterInfo (reg_num, reg_location); 600 } 601 break; 602 603 case DW_CFA_restore_extended : // 0x6 604 { 605 // takes a single unsigned LEB128 argument that represents a register 606 // number. This instruction is identical to DW_CFA_restore except for 607 // the encoding and size of the register argument. 608 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 609 if (unwind_plan.IsValidRowIndex(0) && unwind_plan.GetRowAtIndex(0)->GetRegisterInfo(reg_num, reg_location)) 610 row->SetRegisterInfo (reg_num, reg_location); 611 } 612 break; 613 614 case DW_CFA_undefined : // 0x7 615 { 616 // takes a single unsigned LEB128 argument that represents a register 617 // number. The required action is to set the rule for the specified 618 // register to undefined. 619 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 620 reg_location.SetUndefined(); 621 row->SetRegisterInfo (reg_num, reg_location); 622 } 623 break; 624 625 case DW_CFA_same_value : // 0x8 626 { 627 // takes a single unsigned LEB128 argument that represents a register 628 // number. The required action is to set the rule for the specified 629 // register to same value. 630 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 631 reg_location.SetSame(); 632 row->SetRegisterInfo (reg_num, reg_location); 633 } 634 break; 635 636 case DW_CFA_register : // 0x9 637 { 638 // takes two unsigned LEB128 arguments representing register numbers. 639 // The required action is to set the rule for the first register to be 640 // the second register. 641 642 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 643 uint32_t other_reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 644 reg_location.SetInRegister(other_reg_num); 645 row->SetRegisterInfo (reg_num, reg_location); 646 } 647 break; 648 649 case DW_CFA_remember_state : // 0xA 650 { 651 // These instructions define a stack of information. Encountering the 652 // DW_CFA_remember_state instruction means to save the rules for every 653 // register on the current row on the stack. Encountering the 654 // DW_CFA_restore_state instruction means to pop the set of rules off 655 // the stack and place them in the current row. (This operation is 656 // useful for compilers that move epilogue code into the body of a 657 // function.) 658 stack.push_back (row); 659 UnwindPlan::Row *newrow = new UnwindPlan::Row; 660 *newrow = *row.get(); 661 row.reset (newrow); 662 } 663 break; 664 665 case DW_CFA_restore_state : // 0xB 666 // These instructions define a stack of information. Encountering the 667 // DW_CFA_remember_state instruction means to save the rules for every 668 // register on the current row on the stack. Encountering the 669 // DW_CFA_restore_state instruction means to pop the set of rules off 670 // the stack and place them in the current row. (This operation is 671 // useful for compilers that move epilogue code into the body of a 672 // function.) 673 { 674 row = stack.back (); 675 stack.pop_back (); 676 } 677 break; 678 679 case DW_CFA_def_cfa : // 0xC (CFA Definition Instruction) 680 { 681 // Takes two unsigned LEB128 operands representing a register 682 // number and a (non-factored) offset. The required action 683 // is to define the current CFA rule to use the provided 684 // register and offset. 685 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 686 op_offset = (int32_t)m_cfi_data.GetULEB128(&offset); 687 row->SetCFARegister (reg_num); 688 row->SetCFAOffset (op_offset); 689 } 690 break; 691 692 case DW_CFA_def_cfa_register : // 0xD (CFA Definition Instruction) 693 { 694 // takes a single unsigned LEB128 argument representing a register 695 // number. The required action is to define the current CFA rule to 696 // use the provided register (but to keep the old offset). 697 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 698 row->SetCFARegister (reg_num); 699 } 700 break; 701 702 case DW_CFA_def_cfa_offset : // 0xE (CFA Definition Instruction) 703 { 704 // Takes a single unsigned LEB128 operand representing a 705 // (non-factored) offset. The required action is to define 706 // the current CFA rule to use the provided offset (but 707 // to keep the old register). 708 op_offset = (int32_t)m_cfi_data.GetULEB128(&offset); 709 row->SetCFAOffset (op_offset); 710 } 711 break; 712 713 case DW_CFA_def_cfa_expression : // 0xF (CFA Definition Instruction) 714 { 715 size_t block_len = (size_t)m_cfi_data.GetULEB128(&offset); 716 offset += (uint32_t)block_len; 717 } 718 break; 719 720 case DW_CFA_expression : // 0x10 721 { 722 // Takes two operands: an unsigned LEB128 value representing 723 // a register number, and a DW_FORM_block value representing a DWARF 724 // expression. The required action is to change the rule for the 725 // register indicated by the register number to be an expression(E) 726 // rule where E is the DWARF expression. That is, the DWARF 727 // expression computes the address. The value of the CFA is 728 // pushed on the DWARF evaluation stack prior to execution of 729 // the DWARF expression. 730 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 731 uint32_t block_len = (uint32_t)m_cfi_data.GetULEB128(&offset); 732 const uint8_t *block_data = (uint8_t *)m_cfi_data.GetData(&offset, block_len); 733 734 reg_location.SetAtDWARFExpression(block_data, block_len); 735 row->SetRegisterInfo (reg_num, reg_location); 736 } 737 break; 738 739 case DW_CFA_offset_extended_sf : // 0x11 740 { 741 // takes two operands: an unsigned LEB128 value representing a 742 // register number and a signed LEB128 factored offset. This 743 // instruction is identical to DW_CFA_offset_extended except 744 //that the second operand is signed and factored. 745 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 746 op_offset = (int32_t)m_cfi_data.GetSLEB128(&offset) * data_align; 747 reg_location.SetAtCFAPlusOffset(op_offset); 748 row->SetRegisterInfo (reg_num, reg_location); 749 } 750 break; 751 752 case DW_CFA_def_cfa_sf : // 0x12 (CFA Definition Instruction) 753 { 754 // Takes two operands: an unsigned LEB128 value representing 755 // a register number and a signed LEB128 factored offset. 756 // This instruction is identical to DW_CFA_def_cfa except 757 // that the second operand is signed and factored. 758 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 759 op_offset = (int32_t)m_cfi_data.GetSLEB128(&offset) * data_align; 760 row->SetCFARegister (reg_num); 761 row->SetCFAOffset (op_offset); 762 } 763 break; 764 765 case DW_CFA_def_cfa_offset_sf : // 0x13 (CFA Definition Instruction) 766 { 767 // takes a signed LEB128 operand representing a factored 768 // offset. This instruction is identical to DW_CFA_def_cfa_offset 769 // except that the operand is signed and factored. 770 op_offset = (int32_t)m_cfi_data.GetSLEB128(&offset) * data_align; 771 row->SetCFAOffset (op_offset); 772 } 773 break; 774 775 case DW_CFA_val_expression : // 0x16 776 { 777 // takes two operands: an unsigned LEB128 value representing a register 778 // number, and a DW_FORM_block value representing a DWARF expression. 779 // The required action is to change the rule for the register indicated 780 // by the register number to be a val_expression(E) rule where E is the 781 // DWARF expression. That is, the DWARF expression computes the value of 782 // the given register. The value of the CFA is pushed on the DWARF 783 // evaluation stack prior to execution of the DWARF expression. 784 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 785 uint32_t block_len = (uint32_t)m_cfi_data.GetULEB128(&offset); 786 const uint8_t* block_data = (uint8_t*)m_cfi_data.GetData(&offset, block_len); 787 //#if defined(__i386__) || defined(__x86_64__) 788 // // The EH frame info for EIP and RIP contains code that looks for traps to 789 // // be a specific type and increments the PC. 790 // // For i386: 791 // // DW_CFA_val_expression where: 792 // // eip = DW_OP_breg6(+28), DW_OP_deref, DW_OP_dup, DW_OP_plus_uconst(0x34), 793 // // DW_OP_deref, DW_OP_swap, DW_OP_plus_uconst(0), DW_OP_deref, 794 // // DW_OP_dup, DW_OP_lit3, DW_OP_ne, DW_OP_swap, DW_OP_lit4, DW_OP_ne, 795 // // DW_OP_and, DW_OP_plus 796 // // This basically does a: 797 // // eip = ucontenxt.mcontext32->gpr.eip; 798 // // if (ucontenxt.mcontext32->exc.trapno != 3 && ucontenxt.mcontext32->exc.trapno != 4) 799 // // eip++; 800 // // 801 // // For x86_64: 802 // // DW_CFA_val_expression where: 803 // // rip = DW_OP_breg3(+48), DW_OP_deref, DW_OP_dup, DW_OP_plus_uconst(0x90), DW_OP_deref, 804 // // DW_OP_swap, DW_OP_plus_uconst(0), DW_OP_deref_size(4), DW_OP_dup, DW_OP_lit3, 805 // // DW_OP_ne, DW_OP_swap, DW_OP_lit4, DW_OP_ne, DW_OP_and, DW_OP_plus 806 // // This basically does a: 807 // // rip = ucontenxt.mcontext64->gpr.rip; 808 // // if (ucontenxt.mcontext64->exc.trapno != 3 && ucontenxt.mcontext64->exc.trapno != 4) 809 // // rip++; 810 // // The trap comparisons and increments are not needed as it hoses up the unwound PC which 811 // // is expected to point at least past the instruction that causes the fault/trap. So we 812 // // take it out by trimming the expression right at the first "DW_OP_swap" opcodes 813 // if (block_data != NULL && thread->GetPCRegNum(Thread::GCC) == reg_num) 814 // { 815 // if (thread->Is64Bit()) 816 // { 817 // if (block_len > 9 && block_data[8] == DW_OP_swap && block_data[9] == DW_OP_plus_uconst) 818 // block_len = 8; 819 // } 820 // else 821 // { 822 // if (block_len > 8 && block_data[7] == DW_OP_swap && block_data[8] == DW_OP_plus_uconst) 823 // block_len = 7; 824 // } 825 // } 826 //#endif 827 reg_location.SetIsDWARFExpression(block_data, block_len); 828 row->SetRegisterInfo (reg_num, reg_location); 829 } 830 break; 831 832 case DW_CFA_val_offset : // 0x14 833 case DW_CFA_val_offset_sf : // 0x15 834 default: 835 break; 836 } 837 } 838 } 839 unwind_plan.AppendRow(row); 840 841 return true; 842 } 843