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() == NULL || module_sp->GetObjectFile() == NULL || 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() == NULL || module_sp->GetObjectFile() == NULL || module_sp->GetObjectFile() != &m_objfile) 74 return false; 75 76 if (m_section_sp.get() == NULL || 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() == NULL || 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 == NULL) 101 return false; 102 103 fde_entry = *fde; 104 return true; 105 } 106 107 const DWARFCallFrameInfo::CIE* 108 DWARFCallFrameInfo::GetCIE(dw_offset_t cie_offset) 109 { 110 cie_map_t::iterator pos = m_cie_map.find(cie_offset); 111 112 if (pos != m_cie_map.end()) 113 { 114 // Parse and cache the CIE 115 if (pos->second.get() == NULL) 116 pos->second = ParseCIE (cie_offset); 117 118 return pos->second.get(); 119 } 120 return NULL; 121 } 122 123 DWARFCallFrameInfo::CIESP 124 DWARFCallFrameInfo::ParseCIE (const dw_offset_t cie_offset) 125 { 126 CIESP cie_sp(new CIE(cie_offset)); 127 lldb::offset_t offset = cie_offset; 128 if (m_cfi_data_initialized == false) 129 GetCFIData(); 130 const uint32_t length = m_cfi_data.GetU32(&offset); 131 const dw_offset_t cie_id = m_cfi_data.GetU32(&offset); 132 const dw_offset_t end_offset = cie_offset + length + 4; 133 if (length > 0 && ((!m_is_eh_frame && cie_id == UINT32_MAX) || (m_is_eh_frame && cie_id == 0ul))) 134 { 135 size_t i; 136 // cie.offset = cie_offset; 137 // cie.length = length; 138 // cie.cieID = cieID; 139 cie_sp->ptr_encoding = DW_EH_PE_absptr; 140 cie_sp->version = m_cfi_data.GetU8(&offset); 141 142 for (i=0; i<CFI_AUG_MAX_SIZE; ++i) 143 { 144 cie_sp->augmentation[i] = m_cfi_data.GetU8(&offset); 145 if (cie_sp->augmentation[i] == '\0') 146 { 147 // Zero out remaining bytes in augmentation string 148 for (size_t j = i+1; j<CFI_AUG_MAX_SIZE; ++j) 149 cie_sp->augmentation[j] = '\0'; 150 151 break; 152 } 153 } 154 155 if (i == CFI_AUG_MAX_SIZE && cie_sp->augmentation[CFI_AUG_MAX_SIZE-1] != '\0') 156 { 157 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); 158 return cie_sp; 159 } 160 cie_sp->code_align = (uint32_t)m_cfi_data.GetULEB128(&offset); 161 cie_sp->data_align = (int32_t)m_cfi_data.GetSLEB128(&offset); 162 cie_sp->return_addr_reg_num = m_cfi_data.GetU8(&offset); 163 164 if (cie_sp->augmentation[0]) 165 { 166 // Get the length of the eh_frame augmentation data 167 // which starts with a ULEB128 length in bytes 168 const size_t aug_data_len = (size_t)m_cfi_data.GetULEB128(&offset); 169 const size_t aug_data_end = offset + aug_data_len; 170 const size_t aug_str_len = strlen(cie_sp->augmentation); 171 // A 'z' may be present as the first character of the string. 172 // If present, the Augmentation Data field shall be present. 173 // The contents of the Augmentation Data shall be intepreted 174 // according to other characters in the Augmentation String. 175 if (cie_sp->augmentation[0] == 'z') 176 { 177 // Extract the Augmentation Data 178 size_t aug_str_idx = 0; 179 for (aug_str_idx = 1; aug_str_idx < aug_str_len; aug_str_idx++) 180 { 181 char aug = cie_sp->augmentation[aug_str_idx]; 182 switch (aug) 183 { 184 case 'L': 185 // Indicates the presence of one argument in the 186 // Augmentation Data of the CIE, and a corresponding 187 // argument in the Augmentation Data of the FDE. The 188 // argument in the Augmentation Data of the CIE is 189 // 1-byte and represents the pointer encoding used 190 // for the argument in the Augmentation Data of the 191 // FDE, which is the address of a language-specific 192 // data area (LSDA). The size of the LSDA pointer is 193 // specified by the pointer encoding used. 194 m_cfi_data.GetU8(&offset); 195 break; 196 197 case 'P': 198 // Indicates the presence of two arguments in the 199 // Augmentation Data of the cie_sp-> The first argument 200 // is 1-byte and represents the pointer encoding 201 // used for the second argument, which is the 202 // address of a personality routine handler. The 203 // size of the personality routine pointer is 204 // specified by the pointer encoding used. 205 { 206 uint8_t arg_ptr_encoding = m_cfi_data.GetU8(&offset); 207 m_cfi_data.GetGNUEHPointer(&offset, arg_ptr_encoding, LLDB_INVALID_ADDRESS, LLDB_INVALID_ADDRESS, LLDB_INVALID_ADDRESS); 208 } 209 break; 210 211 case 'R': 212 // A 'R' may be present at any position after the 213 // first character of the string. The Augmentation 214 // Data shall include a 1 byte argument that 215 // represents the pointer encoding for the address 216 // pointers used in the FDE. 217 cie_sp->ptr_encoding = m_cfi_data.GetU8(&offset); 218 break; 219 } 220 } 221 } 222 else if (strcmp(cie_sp->augmentation, "eh") == 0) 223 { 224 // If the Augmentation string has the value "eh", then 225 // the EH Data field shall be present 226 } 227 228 // Set the offset to be the end of the augmentation data just in case 229 // we didn't understand any of the data. 230 offset = (uint32_t)aug_data_end; 231 } 232 233 if (end_offset > offset) 234 { 235 cie_sp->inst_offset = offset; 236 cie_sp->inst_length = end_offset - offset; 237 } 238 while (offset < end_offset) 239 { 240 uint8_t inst = m_cfi_data.GetU8(&offset); 241 uint8_t primary_opcode = inst & 0xC0; 242 uint8_t extended_opcode = inst & 0x3F; 243 244 if (extended_opcode == DW_CFA_def_cfa) 245 { 246 // Takes two unsigned LEB128 operands representing a register 247 // number and a (non-factored) offset. The required action 248 // is to define the current CFA rule to use the provided 249 // register and offset. 250 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 251 int op_offset = (int32_t)m_cfi_data.GetULEB128(&offset); 252 cie_sp->initial_row.SetCFARegister (reg_num); 253 cie_sp->initial_row.SetCFAOffset (op_offset); 254 continue; 255 } 256 if (primary_opcode == DW_CFA_offset) 257 { 258 // 0x80 - high 2 bits are 0x2, lower 6 bits are register. 259 // Takes two arguments: an unsigned LEB128 constant representing a 260 // factored offset and a register number. The required action is to 261 // change the rule for the register indicated by the register number 262 // to be an offset(N) rule with a value of 263 // (N = factored offset * data_align). 264 uint32_t reg_num = extended_opcode; 265 int op_offset = (int32_t)m_cfi_data.GetULEB128(&offset) * cie_sp->data_align; 266 UnwindPlan::Row::RegisterLocation reg_location; 267 reg_location.SetAtCFAPlusOffset(op_offset); 268 cie_sp->initial_row.SetRegisterInfo (reg_num, reg_location); 269 continue; 270 } 271 if (extended_opcode == DW_CFA_nop) 272 { 273 continue; 274 } 275 break; // Stop if we hit an unrecognized opcode 276 } 277 } 278 279 return cie_sp; 280 } 281 282 void 283 DWARFCallFrameInfo::GetCFIData() 284 { 285 if (m_cfi_data_initialized == false) 286 { 287 LogSP log(GetLogIfAllCategoriesSet (LIBLLDB_LOG_UNWIND)); 288 if (log) 289 m_objfile.GetModule()->LogMessage(log.get(), "Reading EH frame info"); 290 m_objfile.ReadSectionData (m_section_sp.get(), m_cfi_data); 291 m_cfi_data_initialized = true; 292 } 293 } 294 // Scan through the eh_frame or debug_frame section looking for FDEs and noting the start/end addresses 295 // of the functions and a pointer back to the function's FDE for later expansion. 296 // Internalize CIEs as we come across them. 297 298 void 299 DWARFCallFrameInfo::GetFDEIndex () 300 { 301 if (m_section_sp.get() == NULL || m_section_sp->IsEncrypted()) 302 return; 303 304 if (m_fde_index_initialized) 305 return; 306 307 Mutex::Locker locker(m_fde_index_mutex); 308 309 if (m_fde_index_initialized) // if two threads hit the locker 310 return; 311 312 Timer scoped_timer (__PRETTY_FUNCTION__, "%s - %s", __PRETTY_FUNCTION__, m_objfile.GetFileSpec().GetFilename().AsCString("")); 313 314 lldb::offset_t offset = 0; 315 if (m_cfi_data_initialized == false) 316 GetCFIData(); 317 while (m_cfi_data.ValidOffsetForDataOfSize (offset, 8)) 318 { 319 const dw_offset_t current_entry = offset; 320 uint32_t len = m_cfi_data.GetU32 (&offset); 321 dw_offset_t next_entry = current_entry + len + 4; 322 dw_offset_t cie_id = m_cfi_data.GetU32 (&offset); 323 324 if (cie_id == 0 || cie_id == UINT32_MAX) 325 { 326 m_cie_map[current_entry] = ParseCIE (current_entry); 327 offset = next_entry; 328 continue; 329 } 330 331 const dw_offset_t cie_offset = current_entry + 4 - cie_id; 332 const CIE *cie = GetCIE (cie_offset); 333 if (cie) 334 { 335 const lldb::addr_t pc_rel_addr = m_section_sp->GetFileAddress(); 336 const lldb::addr_t text_addr = LLDB_INVALID_ADDRESS; 337 const lldb::addr_t data_addr = LLDB_INVALID_ADDRESS; 338 339 lldb::addr_t addr = m_cfi_data.GetGNUEHPointer(&offset, cie->ptr_encoding, pc_rel_addr, text_addr, data_addr); 340 lldb::addr_t length = m_cfi_data.GetGNUEHPointer(&offset, cie->ptr_encoding & DW_EH_PE_MASK_ENCODING, pc_rel_addr, text_addr, data_addr); 341 FDEEntryMap::Entry fde (addr, length, current_entry); 342 m_fde_index.Append(fde); 343 } 344 else 345 { 346 Host::SystemLog (Host::eSystemLogError, 347 "error: unable to find CIE at 0x%8.8x for cie_id = 0x%8.8x for entry at 0x%8.8x.\n", 348 cie_offset, 349 cie_id, 350 current_entry); 351 } 352 offset = next_entry; 353 } 354 m_fde_index.Sort(); 355 m_fde_index_initialized = true; 356 } 357 358 bool 359 DWARFCallFrameInfo::FDEToUnwindPlan (dw_offset_t dwarf_offset, Address startaddr, UnwindPlan& unwind_plan) 360 { 361 lldb::offset_t offset = dwarf_offset; 362 lldb::offset_t current_entry = offset; 363 364 if (m_section_sp.get() == NULL || m_section_sp->IsEncrypted()) 365 return false; 366 367 if (m_cfi_data_initialized == false) 368 GetCFIData(); 369 370 uint32_t length = m_cfi_data.GetU32 (&offset); 371 dw_offset_t cie_offset = m_cfi_data.GetU32 (&offset); 372 373 assert (cie_offset != 0 && cie_offset != UINT32_MAX); 374 375 // Translate the CIE_id from the eh_frame format, which 376 // is relative to the FDE offset, into a __eh_frame section 377 // offset 378 if (m_is_eh_frame) 379 { 380 unwind_plan.SetSourceName ("eh_frame CFI"); 381 cie_offset = current_entry + 4 - cie_offset; 382 unwind_plan.SetUnwindPlanValidAtAllInstructions (eLazyBoolNo); 383 } 384 else 385 { 386 unwind_plan.SetSourceName ("DWARF CFI"); 387 // In theory the debug_frame info should be valid at all call sites 388 // ("asynchronous unwind info" as it is sometimes called) but in practice 389 // gcc et al all emit call frame info for the prologue and call sites, but 390 // not for the epilogue or all the other locations during the function reliably. 391 unwind_plan.SetUnwindPlanValidAtAllInstructions (eLazyBoolNo); 392 } 393 unwind_plan.SetSourcedFromCompiler (eLazyBoolYes); 394 395 const CIE *cie = GetCIE (cie_offset); 396 assert (cie != NULL); 397 398 const dw_offset_t end_offset = current_entry + length + 4; 399 400 const lldb::addr_t pc_rel_addr = m_section_sp->GetFileAddress(); 401 const lldb::addr_t text_addr = LLDB_INVALID_ADDRESS; 402 const lldb::addr_t data_addr = LLDB_INVALID_ADDRESS; 403 lldb::addr_t range_base = m_cfi_data.GetGNUEHPointer(&offset, cie->ptr_encoding, pc_rel_addr, text_addr, data_addr); 404 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); 405 AddressRange range (range_base, m_objfile.GetAddressByteSize(), m_objfile.GetSectionList()); 406 range.SetByteSize (range_len); 407 408 if (cie->augmentation[0] == 'z') 409 { 410 uint32_t aug_data_len = (uint32_t)m_cfi_data.GetULEB128(&offset); 411 offset += aug_data_len; 412 } 413 414 uint32_t reg_num = 0; 415 int32_t op_offset = 0; 416 uint32_t code_align = cie->code_align; 417 int32_t data_align = cie->data_align; 418 419 unwind_plan.SetPlanValidAddressRange (range); 420 UnwindPlan::Row *cie_initial_row = new UnwindPlan::Row; 421 *cie_initial_row = cie->initial_row; 422 UnwindPlan::RowSP row(cie_initial_row); 423 424 unwind_plan.SetRegisterKind (m_reg_kind); 425 unwind_plan.SetReturnAddressRegister (cie->return_addr_reg_num); 426 427 UnwindPlan::Row::RegisterLocation reg_location; 428 while (m_cfi_data.ValidOffset(offset) && offset < end_offset) 429 { 430 uint8_t inst = m_cfi_data.GetU8(&offset); 431 uint8_t primary_opcode = inst & 0xC0; 432 uint8_t extended_opcode = inst & 0x3F; 433 434 if (primary_opcode) 435 { 436 switch (primary_opcode) 437 { 438 case DW_CFA_advance_loc : // (Row Creation Instruction) 439 { // 0x40 - high 2 bits are 0x1, lower 6 bits are delta 440 // takes a single argument that represents a constant delta. The 441 // required action is to create a new table row with a location 442 // value that is computed by taking the current entry's location 443 // value and adding (delta * code_align). All other 444 // values in the new row are initially identical to the current row. 445 unwind_plan.AppendRow(row); 446 UnwindPlan::Row *newrow = new UnwindPlan::Row; 447 *newrow = *row.get(); 448 row.reset (newrow); 449 row->SlideOffset(extended_opcode * code_align); 450 } 451 break; 452 453 case DW_CFA_offset : 454 { // 0x80 - high 2 bits are 0x2, lower 6 bits are register 455 // takes two arguments: an unsigned LEB128 constant representing a 456 // factored offset and a register number. The required action is to 457 // change the rule for the register indicated by the register number 458 // to be an offset(N) rule with a value of 459 // (N = factored offset * data_align). 460 reg_num = extended_opcode; 461 op_offset = (int32_t)m_cfi_data.GetULEB128(&offset) * data_align; 462 reg_location.SetAtCFAPlusOffset(op_offset); 463 row->SetRegisterInfo (reg_num, reg_location); 464 } 465 break; 466 467 case DW_CFA_restore : 468 { // 0xC0 - high 2 bits are 0x3, lower 6 bits are register 469 // takes a single argument that represents a register number. The 470 // required action is to change the rule for the indicated register 471 // to the rule assigned it by the initial_instructions in the CIE. 472 reg_num = extended_opcode; 473 // We only keep enough register locations around to 474 // unwind what is in our thread, and these are organized 475 // by the register index in that state, so we need to convert our 476 // GCC register number from the EH frame info, to a register index 477 478 if (unwind_plan.IsValidRowIndex(0) && unwind_plan.GetRowAtIndex(0)->GetRegisterInfo(reg_num, reg_location)) 479 row->SetRegisterInfo (reg_num, reg_location); 480 } 481 break; 482 } 483 } 484 else 485 { 486 switch (extended_opcode) 487 { 488 case DW_CFA_nop : // 0x0 489 break; 490 491 case DW_CFA_set_loc : // 0x1 (Row Creation Instruction) 492 { 493 // DW_CFA_set_loc takes a single argument that represents an address. 494 // The required action is to create a new table row using the 495 // specified address as the location. All other values in the new row 496 // are initially identical to the current row. The new location value 497 // should always be greater than the current one. 498 unwind_plan.AppendRow(row); 499 UnwindPlan::Row *newrow = new UnwindPlan::Row; 500 *newrow = *row.get(); 501 row.reset (newrow); 502 row->SetOffset(m_cfi_data.GetPointer(&offset) - startaddr.GetFileAddress()); 503 } 504 break; 505 506 case DW_CFA_advance_loc1 : // 0x2 (Row Creation Instruction) 507 { 508 // takes a single uword argument that represents a constant delta. 509 // This instruction is identical to DW_CFA_advance_loc except for the 510 // encoding and size of the delta argument. 511 unwind_plan.AppendRow(row); 512 UnwindPlan::Row *newrow = new UnwindPlan::Row; 513 *newrow = *row.get(); 514 row.reset (newrow); 515 row->SlideOffset (m_cfi_data.GetU8(&offset) * code_align); 516 } 517 break; 518 519 case DW_CFA_advance_loc2 : // 0x3 (Row Creation Instruction) 520 { 521 // takes a single uword argument that represents a constant delta. 522 // This instruction is identical to DW_CFA_advance_loc except for the 523 // encoding and size of the delta argument. 524 unwind_plan.AppendRow(row); 525 UnwindPlan::Row *newrow = new UnwindPlan::Row; 526 *newrow = *row.get(); 527 row.reset (newrow); 528 row->SlideOffset (m_cfi_data.GetU16(&offset) * code_align); 529 } 530 break; 531 532 case DW_CFA_advance_loc4 : // 0x4 (Row Creation Instruction) 533 { 534 // takes a single uword argument that represents a constant delta. 535 // This instruction is identical to DW_CFA_advance_loc except for the 536 // encoding and size of the delta argument. 537 unwind_plan.AppendRow(row); 538 UnwindPlan::Row *newrow = new UnwindPlan::Row; 539 *newrow = *row.get(); 540 row.reset (newrow); 541 row->SlideOffset (m_cfi_data.GetU32(&offset) * code_align); 542 } 543 break; 544 545 case DW_CFA_offset_extended : // 0x5 546 { 547 // takes two unsigned LEB128 arguments representing a register number 548 // and a factored offset. This instruction is identical to DW_CFA_offset 549 // except for the encoding and size of the register argument. 550 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 551 op_offset = (int32_t)m_cfi_data.GetULEB128(&offset) * data_align; 552 reg_location.SetAtCFAPlusOffset(op_offset); 553 row->SetRegisterInfo (reg_num, reg_location); 554 } 555 break; 556 557 case DW_CFA_restore_extended : // 0x6 558 { 559 // takes a single unsigned LEB128 argument that represents a register 560 // number. This instruction is identical to DW_CFA_restore except for 561 // the encoding and size of the register argument. 562 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 563 if (unwind_plan.IsValidRowIndex(0) && unwind_plan.GetRowAtIndex(0)->GetRegisterInfo(reg_num, reg_location)) 564 row->SetRegisterInfo (reg_num, reg_location); 565 } 566 break; 567 568 case DW_CFA_undefined : // 0x7 569 { 570 // takes a single unsigned LEB128 argument that represents a register 571 // number. The required action is to set the rule for the specified 572 // register to undefined. 573 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 574 reg_location.SetUndefined(); 575 row->SetRegisterInfo (reg_num, reg_location); 576 } 577 break; 578 579 case DW_CFA_same_value : // 0x8 580 { 581 // takes a single unsigned LEB128 argument that represents a register 582 // number. The required action is to set the rule for the specified 583 // register to same value. 584 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 585 reg_location.SetSame(); 586 row->SetRegisterInfo (reg_num, reg_location); 587 } 588 break; 589 590 case DW_CFA_register : // 0x9 591 { 592 // takes two unsigned LEB128 arguments representing register numbers. 593 // The required action is to set the rule for the first register to be 594 // the second register. 595 596 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 597 uint32_t other_reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 598 reg_location.SetInRegister(other_reg_num); 599 row->SetRegisterInfo (reg_num, reg_location); 600 } 601 break; 602 603 case DW_CFA_remember_state : // 0xA 604 { 605 // These instructions define a stack of information. Encountering the 606 // DW_CFA_remember_state instruction means to save the rules for every 607 // register on the current row on the stack. Encountering the 608 // DW_CFA_restore_state instruction means to pop the set of rules off 609 // the stack and place them in the current row. (This operation is 610 // useful for compilers that move epilogue code into the body of a 611 // function.) 612 unwind_plan.AppendRow (row); 613 UnwindPlan::Row *newrow = new UnwindPlan::Row; 614 *newrow = *row.get(); 615 row.reset (newrow); 616 } 617 break; 618 619 case DW_CFA_restore_state : // 0xB 620 // These instructions define a stack of information. Encountering the 621 // DW_CFA_remember_state instruction means to save the rules for every 622 // register on the current row on the stack. Encountering the 623 // DW_CFA_restore_state instruction means to pop the set of rules off 624 // the stack and place them in the current row. (This operation is 625 // useful for compilers that move epilogue code into the body of a 626 // function.) 627 { 628 row = unwind_plan.GetRowAtIndex(unwind_plan.GetRowCount() - 1); 629 } 630 break; 631 632 case DW_CFA_def_cfa : // 0xC (CFA Definition Instruction) 633 { 634 // Takes two unsigned LEB128 operands representing a register 635 // number and a (non-factored) offset. The required action 636 // is to define the current CFA rule to use the provided 637 // register and offset. 638 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 639 op_offset = (int32_t)m_cfi_data.GetULEB128(&offset); 640 row->SetCFARegister (reg_num); 641 row->SetCFAOffset (op_offset); 642 } 643 break; 644 645 case DW_CFA_def_cfa_register : // 0xD (CFA Definition Instruction) 646 { 647 // takes a single unsigned LEB128 argument representing a register 648 // number. The required action is to define the current CFA rule to 649 // use the provided register (but to keep the old offset). 650 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 651 row->SetCFARegister (reg_num); 652 } 653 break; 654 655 case DW_CFA_def_cfa_offset : // 0xE (CFA Definition Instruction) 656 { 657 // Takes a single unsigned LEB128 operand representing a 658 // (non-factored) offset. The required action is to define 659 // the current CFA rule to use the provided offset (but 660 // to keep the old register). 661 op_offset = (int32_t)m_cfi_data.GetULEB128(&offset); 662 row->SetCFAOffset (op_offset); 663 } 664 break; 665 666 case DW_CFA_def_cfa_expression : // 0xF (CFA Definition Instruction) 667 { 668 size_t block_len = (size_t)m_cfi_data.GetULEB128(&offset); 669 offset += (uint32_t)block_len; 670 } 671 break; 672 673 case DW_CFA_expression : // 0x10 674 { 675 // Takes two operands: an unsigned LEB128 value representing 676 // a register number, and a DW_FORM_block value representing a DWARF 677 // expression. The required action is to change the rule for the 678 // register indicated by the register number to be an expression(E) 679 // rule where E is the DWARF expression. That is, the DWARF 680 // expression computes the address. The value of the CFA is 681 // pushed on the DWARF evaluation stack prior to execution of 682 // the DWARF expression. 683 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 684 uint32_t block_len = (uint32_t)m_cfi_data.GetULEB128(&offset); 685 const uint8_t *block_data = (uint8_t *)m_cfi_data.GetData(&offset, block_len); 686 687 reg_location.SetAtDWARFExpression(block_data, block_len); 688 row->SetRegisterInfo (reg_num, reg_location); 689 } 690 break; 691 692 case DW_CFA_offset_extended_sf : // 0x11 693 { 694 // takes two operands: an unsigned LEB128 value representing a 695 // register number and a signed LEB128 factored offset. This 696 // instruction is identical to DW_CFA_offset_extended except 697 //that the second operand is signed and factored. 698 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 699 op_offset = (int32_t)m_cfi_data.GetSLEB128(&offset) * data_align; 700 reg_location.SetAtCFAPlusOffset(op_offset); 701 row->SetRegisterInfo (reg_num, reg_location); 702 } 703 break; 704 705 case DW_CFA_def_cfa_sf : // 0x12 (CFA Definition Instruction) 706 { 707 // Takes two operands: an unsigned LEB128 value representing 708 // a register number and a signed LEB128 factored offset. 709 // This instruction is identical to DW_CFA_def_cfa except 710 // that the second operand is signed and factored. 711 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 712 op_offset = (int32_t)m_cfi_data.GetSLEB128(&offset) * data_align; 713 row->SetCFARegister (reg_num); 714 row->SetCFAOffset (op_offset); 715 } 716 break; 717 718 case DW_CFA_def_cfa_offset_sf : // 0x13 (CFA Definition Instruction) 719 { 720 // takes a signed LEB128 operand representing a factored 721 // offset. This instruction is identical to DW_CFA_def_cfa_offset 722 // except that the operand is signed and factored. 723 op_offset = (int32_t)m_cfi_data.GetSLEB128(&offset) * data_align; 724 row->SetCFAOffset (op_offset); 725 } 726 break; 727 728 case DW_CFA_val_expression : // 0x16 729 { 730 // takes two operands: an unsigned LEB128 value representing a register 731 // number, and a DW_FORM_block value representing a DWARF expression. 732 // The required action is to change the rule for the register indicated 733 // by the register number to be a val_expression(E) rule where E is the 734 // DWARF expression. That is, the DWARF expression computes the value of 735 // the given register. The value of the CFA is pushed on the DWARF 736 // evaluation stack prior to execution of the DWARF expression. 737 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 738 uint32_t block_len = (uint32_t)m_cfi_data.GetULEB128(&offset); 739 const uint8_t* block_data = (uint8_t*)m_cfi_data.GetData(&offset, block_len); 740 //#if defined(__i386__) || defined(__x86_64__) 741 // // The EH frame info for EIP and RIP contains code that looks for traps to 742 // // be a specific type and increments the PC. 743 // // For i386: 744 // // DW_CFA_val_expression where: 745 // // eip = DW_OP_breg6(+28), DW_OP_deref, DW_OP_dup, DW_OP_plus_uconst(0x34), 746 // // DW_OP_deref, DW_OP_swap, DW_OP_plus_uconst(0), DW_OP_deref, 747 // // DW_OP_dup, DW_OP_lit3, DW_OP_ne, DW_OP_swap, DW_OP_lit4, DW_OP_ne, 748 // // DW_OP_and, DW_OP_plus 749 // // This basically does a: 750 // // eip = ucontenxt.mcontext32->gpr.eip; 751 // // if (ucontenxt.mcontext32->exc.trapno != 3 && ucontenxt.mcontext32->exc.trapno != 4) 752 // // eip++; 753 // // 754 // // For x86_64: 755 // // DW_CFA_val_expression where: 756 // // rip = DW_OP_breg3(+48), DW_OP_deref, DW_OP_dup, DW_OP_plus_uconst(0x90), DW_OP_deref, 757 // // DW_OP_swap, DW_OP_plus_uconst(0), DW_OP_deref_size(4), DW_OP_dup, DW_OP_lit3, 758 // // DW_OP_ne, DW_OP_swap, DW_OP_lit4, DW_OP_ne, DW_OP_and, DW_OP_plus 759 // // This basically does a: 760 // // rip = ucontenxt.mcontext64->gpr.rip; 761 // // if (ucontenxt.mcontext64->exc.trapno != 3 && ucontenxt.mcontext64->exc.trapno != 4) 762 // // rip++; 763 // // The trap comparisons and increments are not needed as it hoses up the unwound PC which 764 // // is expected to point at least past the instruction that causes the fault/trap. So we 765 // // take it out by trimming the expression right at the first "DW_OP_swap" opcodes 766 // if (block_data != NULL && thread->GetPCRegNum(Thread::GCC) == reg_num) 767 // { 768 // if (thread->Is64Bit()) 769 // { 770 // if (block_len > 9 && block_data[8] == DW_OP_swap && block_data[9] == DW_OP_plus_uconst) 771 // block_len = 8; 772 // } 773 // else 774 // { 775 // if (block_len > 8 && block_data[7] == DW_OP_swap && block_data[8] == DW_OP_plus_uconst) 776 // block_len = 7; 777 // } 778 // } 779 //#endif 780 reg_location.SetIsDWARFExpression(block_data, block_len); 781 row->SetRegisterInfo (reg_num, reg_location); 782 } 783 break; 784 785 case DW_CFA_val_offset : // 0x14 786 case DW_CFA_val_offset_sf : // 0x15 787 default: 788 break; 789 } 790 } 791 } 792 unwind_plan.AppendRow(row); 793 794 return true; 795 } 796