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 std::lock_guard<std::mutex> guard(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 bool clear_address_zeroth_bit = false; 320 ArchSpec arch; 321 if (m_objfile.GetArchitecture (arch)) 322 { 323 if (arch.GetTriple().getArch() == llvm::Triple::arm || arch.GetTriple().getArch() == llvm::Triple::thumb) 324 clear_address_zeroth_bit = true; 325 } 326 327 lldb::offset_t offset = 0; 328 if (m_cfi_data_initialized == false) 329 GetCFIData(); 330 while (m_cfi_data.ValidOffsetForDataOfSize (offset, 8)) 331 { 332 const dw_offset_t current_entry = offset; 333 dw_offset_t cie_id, next_entry, cie_offset; 334 uint32_t len = m_cfi_data.GetU32 (&offset); 335 bool is_64bit = (len == UINT32_MAX); 336 if (is_64bit) { 337 len = m_cfi_data.GetU64 (&offset); 338 cie_id = m_cfi_data.GetU64 (&offset); 339 next_entry = current_entry + len + 12; 340 cie_offset = current_entry + 12 - cie_id; 341 } else { 342 cie_id = m_cfi_data.GetU32 (&offset); 343 next_entry = current_entry + len + 4; 344 cie_offset = current_entry + 4 - cie_id; 345 } 346 347 if (next_entry > m_cfi_data.GetByteSize() + 1) 348 { 349 Host::SystemLog (Host::eSystemLogError, 350 "error: Invalid fde/cie next entry offset of 0x%x found in cie/fde at 0x%x\n", 351 next_entry, 352 current_entry); 353 // Don't trust anything in this eh_frame section if we find blatantly 354 // invalid data. 355 m_fde_index.Clear(); 356 m_fde_index_initialized = true; 357 return; 358 } 359 if (cie_offset > m_cfi_data.GetByteSize()) 360 { 361 Host::SystemLog (Host::eSystemLogError, 362 "error: Invalid cie offset of 0x%x found in cie/fde at 0x%x\n", 363 cie_offset, 364 current_entry); 365 // Don't trust anything in this eh_frame section if we find blatantly 366 // invalid data. 367 m_fde_index.Clear(); 368 m_fde_index_initialized = true; 369 return; 370 } 371 372 if (cie_id == 0 || cie_id == UINT32_MAX || len == 0) 373 { 374 m_cie_map[current_entry] = ParseCIE (current_entry); 375 offset = next_entry; 376 continue; 377 } 378 379 const CIE *cie = GetCIE (cie_offset); 380 if (cie) 381 { 382 const lldb::addr_t pc_rel_addr = m_section_sp->GetFileAddress(); 383 const lldb::addr_t text_addr = LLDB_INVALID_ADDRESS; 384 const lldb::addr_t data_addr = LLDB_INVALID_ADDRESS; 385 386 lldb::addr_t addr = m_cfi_data.GetGNUEHPointer(&offset, cie->ptr_encoding, pc_rel_addr, text_addr, data_addr); 387 if (clear_address_zeroth_bit) 388 addr &= ~1ull; 389 390 lldb::addr_t length = m_cfi_data.GetGNUEHPointer(&offset, cie->ptr_encoding & DW_EH_PE_MASK_ENCODING, pc_rel_addr, text_addr, data_addr); 391 FDEEntryMap::Entry fde (addr, length, current_entry); 392 m_fde_index.Append(fde); 393 } 394 else 395 { 396 Host::SystemLog (Host::eSystemLogError, 397 "error: unable to find CIE at 0x%8.8x for cie_id = 0x%8.8x for entry at 0x%8.8x.\n", 398 cie_offset, 399 cie_id, 400 current_entry); 401 } 402 offset = next_entry; 403 } 404 m_fde_index.Sort(); 405 m_fde_index_initialized = true; 406 } 407 408 bool 409 DWARFCallFrameInfo::FDEToUnwindPlan (dw_offset_t dwarf_offset, Address startaddr, UnwindPlan& unwind_plan) 410 { 411 Log *log = GetLogIfAllCategoriesSet(LIBLLDB_LOG_UNWIND); 412 lldb::offset_t offset = dwarf_offset; 413 lldb::offset_t current_entry = offset; 414 415 if (m_section_sp.get() == nullptr || m_section_sp->IsEncrypted()) 416 return false; 417 418 if (m_cfi_data_initialized == false) 419 GetCFIData(); 420 421 uint32_t length = m_cfi_data.GetU32 (&offset); 422 dw_offset_t cie_offset; 423 bool is_64bit = (length == UINT32_MAX); 424 if (is_64bit) { 425 length = m_cfi_data.GetU64 (&offset); 426 cie_offset = m_cfi_data.GetU64 (&offset); 427 } else { 428 cie_offset = m_cfi_data.GetU32 (&offset); 429 } 430 431 assert (cie_offset != 0 && cie_offset != UINT32_MAX); 432 433 // Translate the CIE_id from the eh_frame format, which 434 // is relative to the FDE offset, into a __eh_frame section 435 // offset 436 if (m_is_eh_frame) 437 { 438 unwind_plan.SetSourceName ("eh_frame CFI"); 439 cie_offset = current_entry + (is_64bit ? 12 : 4) - cie_offset; 440 unwind_plan.SetUnwindPlanValidAtAllInstructions (eLazyBoolNo); 441 } 442 else 443 { 444 unwind_plan.SetSourceName ("DWARF CFI"); 445 // In theory the debug_frame info should be valid at all call sites 446 // ("asynchronous unwind info" as it is sometimes called) but in practice 447 // gcc et al all emit call frame info for the prologue and call sites, but 448 // not for the epilogue or all the other locations during the function reliably. 449 unwind_plan.SetUnwindPlanValidAtAllInstructions (eLazyBoolNo); 450 } 451 unwind_plan.SetSourcedFromCompiler (eLazyBoolYes); 452 453 const CIE *cie = GetCIE (cie_offset); 454 assert (cie != nullptr); 455 456 const dw_offset_t end_offset = current_entry + length + (is_64bit ? 12 : 4); 457 458 const lldb::addr_t pc_rel_addr = m_section_sp->GetFileAddress(); 459 const lldb::addr_t text_addr = LLDB_INVALID_ADDRESS; 460 const lldb::addr_t data_addr = LLDB_INVALID_ADDRESS; 461 lldb::addr_t range_base = m_cfi_data.GetGNUEHPointer(&offset, cie->ptr_encoding, pc_rel_addr, text_addr, data_addr); 462 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); 463 AddressRange range (range_base, m_objfile.GetAddressByteSize(), m_objfile.GetSectionList()); 464 range.SetByteSize (range_len); 465 466 addr_t lsda_data_file_address = LLDB_INVALID_ADDRESS; 467 468 if (cie->augmentation[0] == 'z') 469 { 470 uint32_t aug_data_len = (uint32_t)m_cfi_data.GetULEB128(&offset); 471 if (aug_data_len != 0 && cie->lsda_addr_encoding != DW_EH_PE_omit) 472 { 473 offset_t saved_offset = offset; 474 lsda_data_file_address = m_cfi_data.GetGNUEHPointer(&offset, cie->lsda_addr_encoding, pc_rel_addr, text_addr, data_addr); 475 if (offset - saved_offset != aug_data_len) 476 { 477 // There is more in the augmentation region than we know how to process; 478 // don't read anything. 479 lsda_data_file_address = LLDB_INVALID_ADDRESS; 480 } 481 offset = saved_offset; 482 } 483 offset += aug_data_len; 484 } 485 Address lsda_data; 486 Address personality_function_ptr; 487 488 if (lsda_data_file_address != LLDB_INVALID_ADDRESS && cie->personality_loc != LLDB_INVALID_ADDRESS) 489 { 490 m_objfile.GetModule()->ResolveFileAddress (lsda_data_file_address, lsda_data); 491 m_objfile.GetModule()->ResolveFileAddress (cie->personality_loc, personality_function_ptr); 492 } 493 494 if (lsda_data.IsValid() && personality_function_ptr.IsValid()) 495 { 496 unwind_plan.SetLSDAAddress (lsda_data); 497 unwind_plan.SetPersonalityFunctionPtr (personality_function_ptr); 498 } 499 500 uint32_t code_align = cie->code_align; 501 int32_t data_align = cie->data_align; 502 503 unwind_plan.SetPlanValidAddressRange (range); 504 UnwindPlan::Row *cie_initial_row = new UnwindPlan::Row; 505 *cie_initial_row = cie->initial_row; 506 UnwindPlan::RowSP row(cie_initial_row); 507 508 unwind_plan.SetRegisterKind (m_reg_kind); 509 unwind_plan.SetReturnAddressRegister (cie->return_addr_reg_num); 510 511 std::vector<UnwindPlan::RowSP> stack; 512 513 UnwindPlan::Row::RegisterLocation reg_location; 514 while (m_cfi_data.ValidOffset(offset) && offset < end_offset) 515 { 516 uint8_t inst = m_cfi_data.GetU8(&offset); 517 uint8_t primary_opcode = inst & 0xC0; 518 uint8_t extended_opcode = inst & 0x3F; 519 520 if (!HandleCommonDwarfOpcode(primary_opcode, extended_opcode, data_align, offset, *row)) 521 { 522 if (primary_opcode) 523 { 524 switch (primary_opcode) 525 { 526 case DW_CFA_advance_loc : // (Row Creation Instruction) 527 { // 0x40 - high 2 bits are 0x1, lower 6 bits are delta 528 // takes a single argument that represents a constant delta. The 529 // required action is to create a new table row with a location 530 // value that is computed by taking the current entry's location 531 // value and adding (delta * code_align). All other 532 // values in the new row are initially identical to the current row. 533 unwind_plan.AppendRow(row); 534 UnwindPlan::Row *newrow = new UnwindPlan::Row; 535 *newrow = *row.get(); 536 row.reset (newrow); 537 row->SlideOffset(extended_opcode * code_align); 538 break; 539 } 540 541 case DW_CFA_restore : 542 { // 0xC0 - high 2 bits are 0x3, lower 6 bits are register 543 // takes a single argument that represents a register number. The 544 // required action is to change the rule for the indicated register 545 // to the rule assigned it by the initial_instructions in the CIE. 546 uint32_t reg_num = extended_opcode; 547 // We only keep enough register locations around to 548 // unwind what is in our thread, and these are organized 549 // by the register index in that state, so we need to convert our 550 // eh_frame register number from the EH frame info, to a register index 551 552 if (unwind_plan.IsValidRowIndex(0) && unwind_plan.GetRowAtIndex(0)->GetRegisterInfo(reg_num, reg_location)) 553 row->SetRegisterInfo (reg_num, reg_location); 554 break; 555 } 556 } 557 } 558 else 559 { 560 switch (extended_opcode) 561 { 562 case DW_CFA_set_loc : // 0x1 (Row Creation Instruction) 563 { 564 // DW_CFA_set_loc takes a single argument that represents an address. 565 // The required action is to create a new table row using the 566 // specified address as the location. All other values in the new row 567 // are initially identical to the current row. The new location value 568 // should always be greater than the current one. 569 unwind_plan.AppendRow(row); 570 UnwindPlan::Row *newrow = new UnwindPlan::Row; 571 *newrow = *row.get(); 572 row.reset (newrow); 573 row->SetOffset(m_cfi_data.GetPointer(&offset) - startaddr.GetFileAddress()); 574 break; 575 } 576 577 case DW_CFA_advance_loc1 : // 0x2 (Row Creation Instruction) 578 { 579 // takes a single uword argument that represents a constant delta. 580 // This instruction is identical to DW_CFA_advance_loc except for the 581 // encoding and size of the delta argument. 582 unwind_plan.AppendRow(row); 583 UnwindPlan::Row *newrow = new UnwindPlan::Row; 584 *newrow = *row.get(); 585 row.reset (newrow); 586 row->SlideOffset (m_cfi_data.GetU8(&offset) * code_align); 587 break; 588 } 589 590 case DW_CFA_advance_loc2 : // 0x3 (Row Creation Instruction) 591 { 592 // takes a single uword argument that represents a constant delta. 593 // This instruction is identical to DW_CFA_advance_loc except for the 594 // encoding and size of the delta argument. 595 unwind_plan.AppendRow(row); 596 UnwindPlan::Row *newrow = new UnwindPlan::Row; 597 *newrow = *row.get(); 598 row.reset (newrow); 599 row->SlideOffset (m_cfi_data.GetU16(&offset) * code_align); 600 break; 601 } 602 603 case DW_CFA_advance_loc4 : // 0x4 (Row Creation Instruction) 604 { 605 // takes a single uword argument that represents a constant delta. 606 // This instruction is identical to DW_CFA_advance_loc except for the 607 // encoding and size of the delta argument. 608 unwind_plan.AppendRow(row); 609 UnwindPlan::Row *newrow = new UnwindPlan::Row; 610 *newrow = *row.get(); 611 row.reset (newrow); 612 row->SlideOffset (m_cfi_data.GetU32(&offset) * code_align); 613 break; 614 } 615 616 case DW_CFA_restore_extended : // 0x6 617 { 618 // takes a single unsigned LEB128 argument that represents a register 619 // number. This instruction is identical to DW_CFA_restore except for 620 // the encoding and size of the register argument. 621 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 622 if (unwind_plan.IsValidRowIndex(0) && unwind_plan.GetRowAtIndex(0)->GetRegisterInfo(reg_num, reg_location)) 623 row->SetRegisterInfo (reg_num, reg_location); 624 break; 625 } 626 627 case DW_CFA_remember_state : // 0xA 628 { 629 // These instructions define a stack of information. Encountering the 630 // DW_CFA_remember_state instruction means to save the rules for every 631 // register on the current row on the stack. Encountering the 632 // DW_CFA_restore_state instruction means to pop the set of rules off 633 // the stack and place them in the current row. (This operation is 634 // useful for compilers that move epilogue code into the body of a 635 // function.) 636 stack.push_back (row); 637 UnwindPlan::Row *newrow = new UnwindPlan::Row; 638 *newrow = *row.get(); 639 row.reset (newrow); 640 break; 641 } 642 643 case DW_CFA_restore_state : // 0xB 644 { 645 // These instructions define a stack of information. Encountering the 646 // DW_CFA_remember_state instruction means to save the rules for every 647 // register on the current row on the stack. Encountering the 648 // DW_CFA_restore_state instruction means to pop the set of rules off 649 // the stack and place them in the current row. (This operation is 650 // useful for compilers that move epilogue code into the body of a 651 // function.) 652 if (stack.empty()) 653 { 654 if (log) 655 log->Printf( 656 "DWARFCallFrameInfo::%s(dwarf_offset: %" PRIx32 ", startaddr: %" PRIx64 657 " encountered DW_CFA_restore_state but state stack is empty. Corrupt unwind info?", 658 __FUNCTION__, dwarf_offset, startaddr.GetFileAddress()); 659 break; 660 } 661 lldb::addr_t offset = row->GetOffset (); 662 row = stack.back (); 663 stack.pop_back (); 664 row->SetOffset (offset); 665 break; 666 } 667 668 case DW_CFA_GNU_args_size: // 0x2e 669 { 670 // The DW_CFA_GNU_args_size instruction takes an unsigned LEB128 operand 671 // representing an argument size. This instruction specifies the total of 672 // the size of the arguments which have been pushed onto the stack. 673 674 // TODO: Figure out how we should handle this. 675 m_cfi_data.GetULEB128(&offset); 676 break; 677 } 678 679 case DW_CFA_val_offset : // 0x14 680 case DW_CFA_val_offset_sf : // 0x15 681 default: 682 break; 683 } 684 } 685 } 686 } 687 unwind_plan.AppendRow(row); 688 689 return true; 690 } 691 692 bool 693 DWARFCallFrameInfo::HandleCommonDwarfOpcode(uint8_t primary_opcode, 694 uint8_t extended_opcode, 695 int32_t data_align, 696 lldb::offset_t& offset, 697 UnwindPlan::Row& row) 698 { 699 UnwindPlan::Row::RegisterLocation reg_location; 700 701 if (primary_opcode) 702 { 703 switch (primary_opcode) 704 { 705 case DW_CFA_offset: 706 { // 0x80 - high 2 bits are 0x2, lower 6 bits are register 707 // takes two arguments: an unsigned LEB128 constant representing a 708 // factored offset and a register number. The required action is to 709 // change the rule for the register indicated by the register number 710 // to be an offset(N) rule with a value of 711 // (N = factored offset * data_align). 712 uint8_t reg_num = extended_opcode; 713 int32_t op_offset = (int32_t)m_cfi_data.GetULEB128(&offset) * data_align; 714 reg_location.SetAtCFAPlusOffset(op_offset); 715 row.SetRegisterInfo(reg_num, reg_location); 716 return true; 717 } 718 } 719 } 720 else 721 { 722 switch (extended_opcode) 723 { 724 case DW_CFA_nop : // 0x0 725 return true; 726 727 case DW_CFA_offset_extended : // 0x5 728 { 729 // takes two unsigned LEB128 arguments representing a register number 730 // and a factored offset. This instruction is identical to DW_CFA_offset 731 // except for the encoding and size of the register argument. 732 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 733 int32_t op_offset = (int32_t)m_cfi_data.GetULEB128(&offset) * data_align; 734 UnwindPlan::Row::RegisterLocation reg_location; 735 reg_location.SetAtCFAPlusOffset(op_offset); 736 row.SetRegisterInfo(reg_num, reg_location); 737 return true; 738 } 739 740 case DW_CFA_undefined : // 0x7 741 { 742 // takes a single unsigned LEB128 argument that represents a register 743 // number. The required action is to set the rule for the specified 744 // register to undefined. 745 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 746 UnwindPlan::Row::RegisterLocation reg_location; 747 reg_location.SetUndefined(); 748 row.SetRegisterInfo(reg_num, reg_location); 749 return true; 750 } 751 752 case DW_CFA_same_value : // 0x8 753 { 754 // takes a single unsigned LEB128 argument that represents a register 755 // number. The required action is to set the rule for the specified 756 // register to same value. 757 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 758 UnwindPlan::Row::RegisterLocation reg_location; 759 reg_location.SetSame(); 760 row.SetRegisterInfo (reg_num, reg_location); 761 return true; 762 } 763 764 case DW_CFA_register : // 0x9 765 { 766 // takes two unsigned LEB128 arguments representing register numbers. 767 // The required action is to set the rule for the first register to be 768 // the second register. 769 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 770 uint32_t other_reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 771 UnwindPlan::Row::RegisterLocation reg_location; 772 reg_location.SetInRegister(other_reg_num); 773 row.SetRegisterInfo (reg_num, reg_location); 774 return true; 775 } 776 777 case DW_CFA_def_cfa : // 0xC (CFA Definition Instruction) 778 { 779 // Takes two unsigned LEB128 operands representing a register 780 // number and a (non-factored) offset. The required action 781 // is to define the current CFA rule to use the provided 782 // register and offset. 783 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 784 int32_t op_offset = (int32_t)m_cfi_data.GetULEB128(&offset); 785 row.GetCFAValue().SetIsRegisterPlusOffset (reg_num, op_offset); 786 return true; 787 } 788 789 case DW_CFA_def_cfa_register : // 0xD (CFA Definition Instruction) 790 { 791 // takes a single unsigned LEB128 argument representing a register 792 // number. The required action is to define the current CFA rule to 793 // use the provided register (but to keep the old offset). 794 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 795 row.GetCFAValue().SetIsRegisterPlusOffset (reg_num, row.GetCFAValue().GetOffset()); 796 return true; 797 } 798 799 case DW_CFA_def_cfa_offset : // 0xE (CFA Definition Instruction) 800 { 801 // Takes a single unsigned LEB128 operand representing a 802 // (non-factored) offset. The required action is to define 803 // the current CFA rule to use the provided offset (but 804 // to keep the old register). 805 int32_t op_offset = (int32_t)m_cfi_data.GetULEB128(&offset); 806 row.GetCFAValue().SetIsRegisterPlusOffset(row.GetCFAValue().GetRegisterNumber(), op_offset); 807 return true; 808 } 809 810 case DW_CFA_def_cfa_expression : // 0xF (CFA Definition Instruction) 811 { 812 size_t block_len = (size_t)m_cfi_data.GetULEB128(&offset); 813 const uint8_t *block_data = static_cast<const uint8_t*>(m_cfi_data.GetData(&offset, block_len)); 814 row.GetCFAValue().SetIsDWARFExpression(block_data, block_len); 815 return true; 816 } 817 818 case DW_CFA_expression : // 0x10 819 { 820 // Takes two operands: an unsigned LEB128 value representing 821 // a register number, and a DW_FORM_block value representing a DWARF 822 // expression. The required action is to change the rule for the 823 // register indicated by the register number to be an expression(E) 824 // rule where E is the DWARF expression. That is, the DWARF 825 // expression computes the address. The value of the CFA is 826 // pushed on the DWARF evaluation stack prior to execution of 827 // the DWARF expression. 828 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 829 uint32_t block_len = (uint32_t)m_cfi_data.GetULEB128(&offset); 830 const uint8_t *block_data = static_cast<const uint8_t*>(m_cfi_data.GetData(&offset, block_len)); 831 UnwindPlan::Row::RegisterLocation reg_location; 832 reg_location.SetAtDWARFExpression(block_data, block_len); 833 row.SetRegisterInfo(reg_num, reg_location); 834 return true; 835 } 836 837 case DW_CFA_offset_extended_sf : // 0x11 838 { 839 // takes two operands: an unsigned LEB128 value representing a 840 // register number and a signed LEB128 factored offset. This 841 // instruction is identical to DW_CFA_offset_extended except 842 //that the second operand is signed and factored. 843 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 844 int32_t op_offset = (int32_t)m_cfi_data.GetSLEB128(&offset) * data_align; 845 UnwindPlan::Row::RegisterLocation reg_location; 846 reg_location.SetAtCFAPlusOffset(op_offset); 847 row.SetRegisterInfo(reg_num, reg_location); 848 return true; 849 } 850 851 case DW_CFA_def_cfa_sf : // 0x12 (CFA Definition Instruction) 852 { 853 // Takes two operands: an unsigned LEB128 value representing 854 // a register number and a signed LEB128 factored offset. 855 // This instruction is identical to DW_CFA_def_cfa except 856 // that the second operand is signed and factored. 857 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 858 int32_t op_offset = (int32_t)m_cfi_data.GetSLEB128(&offset) * data_align; 859 row.GetCFAValue().SetIsRegisterPlusOffset (reg_num, op_offset); 860 return true; 861 } 862 863 case DW_CFA_def_cfa_offset_sf : // 0x13 (CFA Definition Instruction) 864 { 865 // takes a signed LEB128 operand representing a factored 866 // offset. This instruction is identical to DW_CFA_def_cfa_offset 867 // except that the operand is signed and factored. 868 int32_t op_offset = (int32_t)m_cfi_data.GetSLEB128(&offset) * data_align; 869 uint32_t cfa_regnum = row.GetCFAValue().GetRegisterNumber(); 870 row.GetCFAValue().SetIsRegisterPlusOffset(cfa_regnum, op_offset); 871 return true; 872 } 873 874 case DW_CFA_val_expression : // 0x16 875 { 876 // takes two operands: an unsigned LEB128 value representing a register 877 // number, and a DW_FORM_block value representing a DWARF expression. 878 // The required action is to change the rule for the register indicated 879 // by the register number to be a val_expression(E) rule where E is the 880 // DWARF expression. That is, the DWARF expression computes the value of 881 // the given register. The value of the CFA is pushed on the DWARF 882 // evaluation stack prior to execution of the DWARF expression. 883 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 884 uint32_t block_len = (uint32_t)m_cfi_data.GetULEB128(&offset); 885 const uint8_t* block_data = (const uint8_t*)m_cfi_data.GetData(&offset, block_len); 886 //#if defined(__i386__) || defined(__x86_64__) 887 // // The EH frame info for EIP and RIP contains code that looks for traps to 888 // // be a specific type and increments the PC. 889 // // For i386: 890 // // DW_CFA_val_expression where: 891 // // eip = DW_OP_breg6(+28), DW_OP_deref, DW_OP_dup, DW_OP_plus_uconst(0x34), 892 // // DW_OP_deref, DW_OP_swap, DW_OP_plus_uconst(0), DW_OP_deref, 893 // // DW_OP_dup, DW_OP_lit3, DW_OP_ne, DW_OP_swap, DW_OP_lit4, DW_OP_ne, 894 // // DW_OP_and, DW_OP_plus 895 // // This basically does a: 896 // // eip = ucontenxt.mcontext32->gpr.eip; 897 // // if (ucontenxt.mcontext32->exc.trapno != 3 && ucontenxt.mcontext32->exc.trapno != 4) 898 // // eip++; 899 // // 900 // // For x86_64: 901 // // DW_CFA_val_expression where: 902 // // rip = DW_OP_breg3(+48), DW_OP_deref, DW_OP_dup, DW_OP_plus_uconst(0x90), DW_OP_deref, 903 // // DW_OP_swap, DW_OP_plus_uconst(0), DW_OP_deref_size(4), DW_OP_dup, DW_OP_lit3, 904 // // DW_OP_ne, DW_OP_swap, DW_OP_lit4, DW_OP_ne, DW_OP_and, DW_OP_plus 905 // // This basically does a: 906 // // rip = ucontenxt.mcontext64->gpr.rip; 907 // // if (ucontenxt.mcontext64->exc.trapno != 3 && ucontenxt.mcontext64->exc.trapno != 4) 908 // // rip++; 909 // // The trap comparisons and increments are not needed as it hoses up the unwound PC which 910 // // is expected to point at least past the instruction that causes the fault/trap. So we 911 // // take it out by trimming the expression right at the first "DW_OP_swap" opcodes 912 // if (block_data != NULL && thread->GetPCRegNum(Thread::GCC) == reg_num) 913 // { 914 // if (thread->Is64Bit()) 915 // { 916 // if (block_len > 9 && block_data[8] == DW_OP_swap && block_data[9] == DW_OP_plus_uconst) 917 // block_len = 8; 918 // } 919 // else 920 // { 921 // if (block_len > 8 && block_data[7] == DW_OP_swap && block_data[8] == DW_OP_plus_uconst) 922 // block_len = 7; 923 // } 924 // } 925 //#endif 926 reg_location.SetIsDWARFExpression(block_data, block_len); 927 row.SetRegisterInfo (reg_num, reg_location); 928 return true; 929 } 930 } 931 } 932 return false; 933 } 934 935 void 936 DWARFCallFrameInfo::ForEachFDEEntries( 937 const std::function<bool(lldb::addr_t, uint32_t, dw_offset_t)>& callback) 938 { 939 GetFDEIndex(); 940 941 for (size_t i = 0, c = m_fde_index.GetSize(); i < c; ++i) 942 { 943 const FDEEntryMap::Entry& entry = m_fde_index.GetEntryRef(i); 944 if (!callback(entry.base, entry.size, entry.data)) 945 break; 946 } 947 } 948