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 interpreted 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 (!HandleCommonDwarfOpcode(primary_opcode, extended_opcode, cie_sp->data_align, offset, cie_sp->initial_row)) 280 break; // Stop if we hit an unrecognized opcode 281 } 282 } 283 284 return cie_sp; 285 } 286 287 void 288 DWARFCallFrameInfo::GetCFIData() 289 { 290 if (m_cfi_data_initialized == false) 291 { 292 Log *log(GetLogIfAllCategoriesSet (LIBLLDB_LOG_UNWIND)); 293 if (log) 294 m_objfile.GetModule()->LogMessage(log, "Reading EH frame info"); 295 m_objfile.ReadSectionData (m_section_sp.get(), m_cfi_data); 296 m_cfi_data_initialized = true; 297 } 298 } 299 // Scan through the eh_frame or debug_frame section looking for FDEs and noting the start/end addresses 300 // of the functions and a pointer back to the function's FDE for later expansion. 301 // Internalize CIEs as we come across them. 302 303 void 304 DWARFCallFrameInfo::GetFDEIndex () 305 { 306 if (m_section_sp.get() == nullptr || m_section_sp->IsEncrypted()) 307 return; 308 309 if (m_fde_index_initialized) 310 return; 311 312 Mutex::Locker locker(m_fde_index_mutex); 313 314 if (m_fde_index_initialized) // if two threads hit the locker 315 return; 316 317 Timer scoped_timer (__PRETTY_FUNCTION__, "%s - %s", __PRETTY_FUNCTION__, m_objfile.GetFileSpec().GetFilename().AsCString("")); 318 319 lldb::offset_t offset = 0; 320 if (m_cfi_data_initialized == false) 321 GetCFIData(); 322 while (m_cfi_data.ValidOffsetForDataOfSize (offset, 8)) 323 { 324 const dw_offset_t current_entry = offset; 325 dw_offset_t cie_id, next_entry, cie_offset; 326 uint32_t len = m_cfi_data.GetU32 (&offset); 327 bool is_64bit = (len == UINT32_MAX); 328 if (is_64bit) { 329 len = m_cfi_data.GetU64 (&offset); 330 cie_id = m_cfi_data.GetU64 (&offset); 331 next_entry = current_entry + len + 12; 332 cie_offset = current_entry + 12 - cie_id; 333 } else { 334 cie_id = m_cfi_data.GetU32 (&offset); 335 next_entry = current_entry + len + 4; 336 cie_offset = current_entry + 4 - cie_id; 337 } 338 339 if (next_entry > m_cfi_data.GetByteSize() + 1) 340 { 341 Host::SystemLog (Host::eSystemLogError, 342 "error: Invalid fde/cie next entry offset of 0x%x found in cie/fde at 0x%x\n", 343 next_entry, 344 current_entry); 345 // Don't trust anything in this eh_frame section if we find blatantly 346 // invalid data. 347 m_fde_index.Clear(); 348 m_fde_index_initialized = true; 349 return; 350 } 351 if (cie_offset > m_cfi_data.GetByteSize()) 352 { 353 Host::SystemLog (Host::eSystemLogError, 354 "error: Invalid cie offset of 0x%x found in cie/fde at 0x%x\n", 355 cie_offset, 356 current_entry); 357 // Don't trust anything in this eh_frame section if we find blatantly 358 // invalid data. 359 m_fde_index.Clear(); 360 m_fde_index_initialized = true; 361 return; 362 } 363 364 if (cie_id == 0 || cie_id == UINT32_MAX || len == 0) 365 { 366 m_cie_map[current_entry] = ParseCIE (current_entry); 367 offset = next_entry; 368 continue; 369 } 370 371 const CIE *cie = GetCIE (cie_offset); 372 if (cie) 373 { 374 const lldb::addr_t pc_rel_addr = m_section_sp->GetFileAddress(); 375 const lldb::addr_t text_addr = LLDB_INVALID_ADDRESS; 376 const lldb::addr_t data_addr = LLDB_INVALID_ADDRESS; 377 378 lldb::addr_t addr = m_cfi_data.GetGNUEHPointer(&offset, cie->ptr_encoding, pc_rel_addr, text_addr, data_addr); 379 lldb::addr_t length = m_cfi_data.GetGNUEHPointer(&offset, cie->ptr_encoding & DW_EH_PE_MASK_ENCODING, pc_rel_addr, text_addr, data_addr); 380 FDEEntryMap::Entry fde (addr, length, current_entry); 381 m_fde_index.Append(fde); 382 } 383 else 384 { 385 Host::SystemLog (Host::eSystemLogError, 386 "error: unable to find CIE at 0x%8.8x for cie_id = 0x%8.8x for entry at 0x%8.8x.\n", 387 cie_offset, 388 cie_id, 389 current_entry); 390 } 391 offset = next_entry; 392 } 393 m_fde_index.Sort(); 394 m_fde_index_initialized = true; 395 } 396 397 bool 398 DWARFCallFrameInfo::FDEToUnwindPlan (dw_offset_t dwarf_offset, Address startaddr, UnwindPlan& unwind_plan) 399 { 400 lldb::offset_t offset = dwarf_offset; 401 lldb::offset_t current_entry = offset; 402 403 if (m_section_sp.get() == nullptr || m_section_sp->IsEncrypted()) 404 return false; 405 406 if (m_cfi_data_initialized == false) 407 GetCFIData(); 408 409 uint32_t length = m_cfi_data.GetU32 (&offset); 410 dw_offset_t cie_offset; 411 bool is_64bit = (length == UINT32_MAX); 412 if (is_64bit) { 413 length = m_cfi_data.GetU64 (&offset); 414 cie_offset = m_cfi_data.GetU64 (&offset); 415 } else { 416 cie_offset = m_cfi_data.GetU32 (&offset); 417 } 418 419 assert (cie_offset != 0 && cie_offset != UINT32_MAX); 420 421 // Translate the CIE_id from the eh_frame format, which 422 // is relative to the FDE offset, into a __eh_frame section 423 // offset 424 if (m_is_eh_frame) 425 { 426 unwind_plan.SetSourceName ("eh_frame CFI"); 427 cie_offset = current_entry + (is_64bit ? 12 : 4) - cie_offset; 428 unwind_plan.SetUnwindPlanValidAtAllInstructions (eLazyBoolNo); 429 } 430 else 431 { 432 unwind_plan.SetSourceName ("DWARF CFI"); 433 // In theory the debug_frame info should be valid at all call sites 434 // ("asynchronous unwind info" as it is sometimes called) but in practice 435 // gcc et al all emit call frame info for the prologue and call sites, but 436 // not for the epilogue or all the other locations during the function reliably. 437 unwind_plan.SetUnwindPlanValidAtAllInstructions (eLazyBoolNo); 438 } 439 unwind_plan.SetSourcedFromCompiler (eLazyBoolYes); 440 441 const CIE *cie = GetCIE (cie_offset); 442 assert (cie != nullptr); 443 444 const dw_offset_t end_offset = current_entry + length + (is_64bit ? 12 : 4); 445 446 const lldb::addr_t pc_rel_addr = m_section_sp->GetFileAddress(); 447 const lldb::addr_t text_addr = LLDB_INVALID_ADDRESS; 448 const lldb::addr_t data_addr = LLDB_INVALID_ADDRESS; 449 lldb::addr_t range_base = m_cfi_data.GetGNUEHPointer(&offset, cie->ptr_encoding, pc_rel_addr, text_addr, data_addr); 450 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); 451 AddressRange range (range_base, m_objfile.GetAddressByteSize(), m_objfile.GetSectionList()); 452 range.SetByteSize (range_len); 453 454 addr_t lsda_data_file_address = LLDB_INVALID_ADDRESS; 455 456 if (cie->augmentation[0] == 'z') 457 { 458 uint32_t aug_data_len = (uint32_t)m_cfi_data.GetULEB128(&offset); 459 if (aug_data_len != 0 && cie->lsda_addr_encoding != DW_EH_PE_omit) 460 { 461 offset_t saved_offset = offset; 462 lsda_data_file_address = m_cfi_data.GetGNUEHPointer(&offset, cie->lsda_addr_encoding, pc_rel_addr, text_addr, data_addr); 463 if (offset - saved_offset != aug_data_len) 464 { 465 // There is more in the augmentation region than we know how to process; 466 // don't read anything. 467 lsda_data_file_address = LLDB_INVALID_ADDRESS; 468 } 469 offset = saved_offset; 470 } 471 offset += aug_data_len; 472 } 473 Address lsda_data; 474 Address personality_function_ptr; 475 476 if (lsda_data_file_address != LLDB_INVALID_ADDRESS && cie->personality_loc != LLDB_INVALID_ADDRESS) 477 { 478 m_objfile.GetModule()->ResolveFileAddress (lsda_data_file_address, lsda_data); 479 m_objfile.GetModule()->ResolveFileAddress (cie->personality_loc, personality_function_ptr); 480 } 481 482 if (lsda_data.IsValid() && personality_function_ptr.IsValid()) 483 { 484 unwind_plan.SetLSDAAddress (lsda_data); 485 unwind_plan.SetPersonalityFunctionPtr (personality_function_ptr); 486 } 487 488 uint32_t code_align = cie->code_align; 489 int32_t data_align = cie->data_align; 490 491 unwind_plan.SetPlanValidAddressRange (range); 492 UnwindPlan::Row *cie_initial_row = new UnwindPlan::Row; 493 *cie_initial_row = cie->initial_row; 494 UnwindPlan::RowSP row(cie_initial_row); 495 496 unwind_plan.SetRegisterKind (m_reg_kind); 497 unwind_plan.SetReturnAddressRegister (cie->return_addr_reg_num); 498 499 std::vector<UnwindPlan::RowSP> stack; 500 501 UnwindPlan::Row::RegisterLocation reg_location; 502 while (m_cfi_data.ValidOffset(offset) && offset < end_offset) 503 { 504 uint8_t inst = m_cfi_data.GetU8(&offset); 505 uint8_t primary_opcode = inst & 0xC0; 506 uint8_t extended_opcode = inst & 0x3F; 507 508 if (!HandleCommonDwarfOpcode(primary_opcode, extended_opcode, data_align, offset, *row)) 509 { 510 if (primary_opcode) 511 { 512 switch (primary_opcode) 513 { 514 case DW_CFA_advance_loc : // (Row Creation Instruction) 515 { // 0x40 - high 2 bits are 0x1, lower 6 bits are delta 516 // takes a single argument that represents a constant delta. The 517 // required action is to create a new table row with a location 518 // value that is computed by taking the current entry's location 519 // value and adding (delta * code_align). All other 520 // values in the new row are initially identical to the current row. 521 unwind_plan.AppendRow(row); 522 UnwindPlan::Row *newrow = new UnwindPlan::Row; 523 *newrow = *row.get(); 524 row.reset (newrow); 525 row->SlideOffset(extended_opcode * code_align); 526 break; 527 } 528 529 case DW_CFA_restore : 530 { // 0xC0 - high 2 bits are 0x3, lower 6 bits are register 531 // takes a single argument that represents a register number. The 532 // required action is to change the rule for the indicated register 533 // to the rule assigned it by the initial_instructions in the CIE. 534 uint32_t reg_num = extended_opcode; 535 // We only keep enough register locations around to 536 // unwind what is in our thread, and these are organized 537 // by the register index in that state, so we need to convert our 538 // eh_frame register number from the EH frame info, to a register index 539 540 if (unwind_plan.IsValidRowIndex(0) && unwind_plan.GetRowAtIndex(0)->GetRegisterInfo(reg_num, reg_location)) 541 row->SetRegisterInfo (reg_num, reg_location); 542 break; 543 } 544 } 545 } 546 else 547 { 548 switch (extended_opcode) 549 { 550 case DW_CFA_set_loc : // 0x1 (Row Creation Instruction) 551 { 552 // DW_CFA_set_loc takes a single argument that represents an address. 553 // The required action is to create a new table row using the 554 // specified address as the location. All other values in the new row 555 // are initially identical to the current row. The new location value 556 // should always be greater than the current one. 557 unwind_plan.AppendRow(row); 558 UnwindPlan::Row *newrow = new UnwindPlan::Row; 559 *newrow = *row.get(); 560 row.reset (newrow); 561 row->SetOffset(m_cfi_data.GetPointer(&offset) - startaddr.GetFileAddress()); 562 break; 563 } 564 565 case DW_CFA_advance_loc1 : // 0x2 (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.GetU8(&offset) * code_align); 575 break; 576 } 577 578 case DW_CFA_advance_loc2 : // 0x3 (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.GetU16(&offset) * code_align); 588 break; 589 } 590 591 case DW_CFA_advance_loc4 : // 0x4 (Row Creation Instruction) 592 { 593 // takes a single uword argument that represents a constant delta. 594 // This instruction is identical to DW_CFA_advance_loc except for the 595 // encoding and size of the delta argument. 596 unwind_plan.AppendRow(row); 597 UnwindPlan::Row *newrow = new UnwindPlan::Row; 598 *newrow = *row.get(); 599 row.reset (newrow); 600 row->SlideOffset (m_cfi_data.GetU32(&offset) * code_align); 601 break; 602 } 603 604 case DW_CFA_restore_extended : // 0x6 605 { 606 // takes a single unsigned LEB128 argument that represents a register 607 // number. This instruction is identical to DW_CFA_restore except for 608 // the encoding and size of the register argument. 609 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 610 if (unwind_plan.IsValidRowIndex(0) && unwind_plan.GetRowAtIndex(0)->GetRegisterInfo(reg_num, reg_location)) 611 row->SetRegisterInfo (reg_num, reg_location); 612 break; 613 } 614 615 case DW_CFA_remember_state : // 0xA 616 { 617 // These instructions define a stack of information. Encountering the 618 // DW_CFA_remember_state instruction means to save the rules for every 619 // register on the current row on the stack. Encountering the 620 // DW_CFA_restore_state instruction means to pop the set of rules off 621 // the stack and place them in the current row. (This operation is 622 // useful for compilers that move epilogue code into the body of a 623 // function.) 624 stack.push_back (row); 625 UnwindPlan::Row *newrow = new UnwindPlan::Row; 626 *newrow = *row.get(); 627 row.reset (newrow); 628 break; 629 } 630 631 case DW_CFA_restore_state : // 0xB 632 { 633 // These instructions define a stack of information. Encountering the 634 // DW_CFA_remember_state instruction means to save the rules for every 635 // register on the current row on the stack. Encountering the 636 // DW_CFA_restore_state instruction means to pop the set of rules off 637 // the stack and place them in the current row. (This operation is 638 // useful for compilers that move epilogue code into the body of a 639 // function.) 640 lldb::addr_t offset = row->GetOffset (); 641 row = stack.back (); 642 stack.pop_back (); 643 row->SetOffset (offset); 644 break; 645 } 646 647 case DW_CFA_val_offset : // 0x14 648 case DW_CFA_val_offset_sf : // 0x15 649 default: 650 break; 651 } 652 } 653 } 654 } 655 unwind_plan.AppendRow(row); 656 657 return true; 658 } 659 660 bool 661 DWARFCallFrameInfo::HandleCommonDwarfOpcode(uint8_t primary_opcode, 662 uint8_t extended_opcode, 663 int32_t data_align, 664 lldb::offset_t& offset, 665 UnwindPlan::Row& row) 666 { 667 UnwindPlan::Row::RegisterLocation reg_location; 668 669 if (primary_opcode) 670 { 671 switch (primary_opcode) 672 { 673 case DW_CFA_offset: 674 { // 0x80 - high 2 bits are 0x2, lower 6 bits are register 675 // takes two arguments: an unsigned LEB128 constant representing a 676 // factored offset and a register number. The required action is to 677 // change the rule for the register indicated by the register number 678 // to be an offset(N) rule with a value of 679 // (N = factored offset * data_align). 680 uint8_t reg_num = extended_opcode; 681 int32_t op_offset = (int32_t)m_cfi_data.GetULEB128(&offset) * data_align; 682 reg_location.SetAtCFAPlusOffset(op_offset); 683 row.SetRegisterInfo(reg_num, reg_location); 684 return true; 685 } 686 } 687 } 688 else 689 { 690 switch (extended_opcode) 691 { 692 case DW_CFA_nop : // 0x0 693 return true; 694 695 case DW_CFA_offset_extended : // 0x5 696 { 697 // takes two unsigned LEB128 arguments representing a register number 698 // and a factored offset. This instruction is identical to DW_CFA_offset 699 // except for the encoding and size of the register argument. 700 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 701 int32_t op_offset = (int32_t)m_cfi_data.GetULEB128(&offset) * data_align; 702 UnwindPlan::Row::RegisterLocation reg_location; 703 reg_location.SetAtCFAPlusOffset(op_offset); 704 row.SetRegisterInfo(reg_num, reg_location); 705 return true; 706 } 707 708 case DW_CFA_undefined : // 0x7 709 { 710 // takes a single unsigned LEB128 argument that represents a register 711 // number. The required action is to set the rule for the specified 712 // register to undefined. 713 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 714 UnwindPlan::Row::RegisterLocation reg_location; 715 reg_location.SetUndefined(); 716 row.SetRegisterInfo(reg_num, reg_location); 717 return true; 718 } 719 720 case DW_CFA_same_value : // 0x8 721 { 722 // takes a single unsigned LEB128 argument that represents a register 723 // number. The required action is to set the rule for the specified 724 // register to same value. 725 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 726 UnwindPlan::Row::RegisterLocation reg_location; 727 reg_location.SetSame(); 728 row.SetRegisterInfo (reg_num, reg_location); 729 return true; 730 } 731 732 case DW_CFA_register : // 0x9 733 { 734 // takes two unsigned LEB128 arguments representing register numbers. 735 // The required action is to set the rule for the first register to be 736 // the second register. 737 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 738 uint32_t other_reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 739 UnwindPlan::Row::RegisterLocation reg_location; 740 reg_location.SetInRegister(other_reg_num); 741 row.SetRegisterInfo (reg_num, reg_location); 742 return true; 743 } 744 745 case DW_CFA_def_cfa : // 0xC (CFA Definition Instruction) 746 { 747 // Takes two unsigned LEB128 operands representing a register 748 // number and a (non-factored) offset. The required action 749 // is to define the current CFA rule to use the provided 750 // register and offset. 751 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 752 int32_t op_offset = (int32_t)m_cfi_data.GetULEB128(&offset); 753 row.GetCFAValue().SetIsRegisterPlusOffset (reg_num, op_offset); 754 return true; 755 } 756 757 case DW_CFA_def_cfa_register : // 0xD (CFA Definition Instruction) 758 { 759 // takes a single unsigned LEB128 argument representing a register 760 // number. The required action is to define the current CFA rule to 761 // use the provided register (but to keep the old offset). 762 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 763 row.GetCFAValue().SetIsRegisterPlusOffset (reg_num, row.GetCFAValue().GetOffset()); 764 return true; 765 } 766 767 case DW_CFA_def_cfa_offset : // 0xE (CFA Definition Instruction) 768 { 769 // Takes a single unsigned LEB128 operand representing a 770 // (non-factored) offset. The required action is to define 771 // the current CFA rule to use the provided offset (but 772 // to keep the old register). 773 int32_t op_offset = (int32_t)m_cfi_data.GetULEB128(&offset); 774 row.GetCFAValue().SetIsRegisterPlusOffset(row.GetCFAValue().GetRegisterNumber(), op_offset); 775 return true; 776 } 777 778 case DW_CFA_def_cfa_expression : // 0xF (CFA Definition Instruction) 779 { 780 size_t block_len = (size_t)m_cfi_data.GetULEB128(&offset); 781 const uint8_t *block_data = static_cast<const uint8_t*>(m_cfi_data.GetData(&offset, block_len)); 782 row.GetCFAValue().SetIsDWARFExpression(block_data, block_len); 783 return true; 784 } 785 786 case DW_CFA_expression : // 0x10 787 { 788 // Takes two operands: an unsigned LEB128 value representing 789 // a register number, and a DW_FORM_block value representing a DWARF 790 // expression. The required action is to change the rule for the 791 // register indicated by the register number to be an expression(E) 792 // rule where E is the DWARF expression. That is, the DWARF 793 // expression computes the address. The value of the CFA is 794 // pushed on the DWARF evaluation stack prior to execution of 795 // the DWARF expression. 796 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 797 uint32_t block_len = (uint32_t)m_cfi_data.GetULEB128(&offset); 798 const uint8_t *block_data = static_cast<const uint8_t*>(m_cfi_data.GetData(&offset, block_len)); 799 UnwindPlan::Row::RegisterLocation reg_location; 800 reg_location.SetAtDWARFExpression(block_data, block_len); 801 row.SetRegisterInfo(reg_num, reg_location); 802 return true; 803 } 804 805 case DW_CFA_offset_extended_sf : // 0x11 806 { 807 // takes two operands: an unsigned LEB128 value representing a 808 // register number and a signed LEB128 factored offset. This 809 // instruction is identical to DW_CFA_offset_extended except 810 //that the second operand is signed and factored. 811 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 812 int32_t op_offset = (int32_t)m_cfi_data.GetSLEB128(&offset) * data_align; 813 UnwindPlan::Row::RegisterLocation reg_location; 814 reg_location.SetAtCFAPlusOffset(op_offset); 815 row.SetRegisterInfo(reg_num, reg_location); 816 return true; 817 } 818 819 case DW_CFA_def_cfa_sf : // 0x12 (CFA Definition Instruction) 820 { 821 // Takes two operands: an unsigned LEB128 value representing 822 // a register number and a signed LEB128 factored offset. 823 // This instruction is identical to DW_CFA_def_cfa except 824 // that the second operand is signed and factored. 825 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 826 int32_t op_offset = (int32_t)m_cfi_data.GetSLEB128(&offset) * data_align; 827 row.GetCFAValue().SetIsRegisterPlusOffset (reg_num, op_offset); 828 return true; 829 } 830 831 case DW_CFA_def_cfa_offset_sf : // 0x13 (CFA Definition Instruction) 832 { 833 // takes a signed LEB128 operand representing a factored 834 // offset. This instruction is identical to DW_CFA_def_cfa_offset 835 // except that the operand is signed and factored. 836 int32_t op_offset = (int32_t)m_cfi_data.GetSLEB128(&offset) * data_align; 837 uint32_t cfa_regnum = row.GetCFAValue().GetRegisterNumber(); 838 row.GetCFAValue().SetIsRegisterPlusOffset(cfa_regnum, op_offset); 839 return true; 840 } 841 842 case DW_CFA_val_expression : // 0x16 843 { 844 // takes two operands: an unsigned LEB128 value representing a register 845 // number, and a DW_FORM_block value representing a DWARF expression. 846 // The required action is to change the rule for the register indicated 847 // by the register number to be a val_expression(E) rule where E is the 848 // DWARF expression. That is, the DWARF expression computes the value of 849 // the given register. The value of the CFA is pushed on the DWARF 850 // evaluation stack prior to execution of the DWARF expression. 851 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 852 uint32_t block_len = (uint32_t)m_cfi_data.GetULEB128(&offset); 853 const uint8_t* block_data = (const uint8_t*)m_cfi_data.GetData(&offset, block_len); 854 //#if defined(__i386__) || defined(__x86_64__) 855 // // The EH frame info for EIP and RIP contains code that looks for traps to 856 // // be a specific type and increments the PC. 857 // // For i386: 858 // // DW_CFA_val_expression where: 859 // // eip = DW_OP_breg6(+28), DW_OP_deref, DW_OP_dup, DW_OP_plus_uconst(0x34), 860 // // DW_OP_deref, DW_OP_swap, DW_OP_plus_uconst(0), DW_OP_deref, 861 // // DW_OP_dup, DW_OP_lit3, DW_OP_ne, DW_OP_swap, DW_OP_lit4, DW_OP_ne, 862 // // DW_OP_and, DW_OP_plus 863 // // This basically does a: 864 // // eip = ucontenxt.mcontext32->gpr.eip; 865 // // if (ucontenxt.mcontext32->exc.trapno != 3 && ucontenxt.mcontext32->exc.trapno != 4) 866 // // eip++; 867 // // 868 // // For x86_64: 869 // // DW_CFA_val_expression where: 870 // // rip = DW_OP_breg3(+48), DW_OP_deref, DW_OP_dup, DW_OP_plus_uconst(0x90), DW_OP_deref, 871 // // DW_OP_swap, DW_OP_plus_uconst(0), DW_OP_deref_size(4), DW_OP_dup, DW_OP_lit3, 872 // // DW_OP_ne, DW_OP_swap, DW_OP_lit4, DW_OP_ne, DW_OP_and, DW_OP_plus 873 // // This basically does a: 874 // // rip = ucontenxt.mcontext64->gpr.rip; 875 // // if (ucontenxt.mcontext64->exc.trapno != 3 && ucontenxt.mcontext64->exc.trapno != 4) 876 // // rip++; 877 // // The trap comparisons and increments are not needed as it hoses up the unwound PC which 878 // // is expected to point at least past the instruction that causes the fault/trap. So we 879 // // take it out by trimming the expression right at the first "DW_OP_swap" opcodes 880 // if (block_data != NULL && thread->GetPCRegNum(Thread::GCC) == reg_num) 881 // { 882 // if (thread->Is64Bit()) 883 // { 884 // if (block_len > 9 && block_data[8] == DW_OP_swap && block_data[9] == DW_OP_plus_uconst) 885 // block_len = 8; 886 // } 887 // else 888 // { 889 // if (block_len > 8 && block_data[7] == DW_OP_swap && block_data[8] == DW_OP_plus_uconst) 890 // block_len = 7; 891 // } 892 // } 893 //#endif 894 reg_location.SetIsDWARFExpression(block_data, block_len); 895 row.SetRegisterInfo (reg_num, reg_location); 896 return true; 897 } 898 } 899 } 900 return false; 901 } 902 903 void 904 DWARFCallFrameInfo::ForEachFDEEntries( 905 const std::function<bool(lldb::addr_t, uint32_t, dw_offset_t)>& callback) 906 { 907 GetFDEIndex(); 908 909 for (size_t i = 0, c = m_fde_index.GetSize(); i < c; ++i) 910 { 911 const FDEEntryMap::Entry& entry = m_fde_index.GetEntryRef(i); 912 if (!callback(entry.base, entry.size, entry.data)) 913 break; 914 } 915 } 916