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/Host/Host.h" 21 #include "lldb/Symbol/DWARFCallFrameInfo.h" 22 #include "lldb/Symbol/ObjectFile.h" 23 #include "lldb/Symbol/UnwindPlan.h" 24 #include "lldb/Target/RegisterContext.h" 25 #include "lldb/Target/Thread.h" 26 27 using namespace lldb; 28 using namespace lldb_private; 29 30 DWARFCallFrameInfo::DWARFCallFrameInfo(ObjectFile& objfile, SectionSP& section_sp, lldb::RegisterKind reg_kind, bool is_eh_frame) : 31 m_objfile (objfile), 32 m_section_sp (section_sp), 33 m_reg_kind (reg_kind), // The flavor of registers that the CFI data uses (enum RegisterKind) 34 m_flags (), 35 m_cie_map (), 36 m_cfi_data (), 37 m_cfi_data_initialized (false), 38 m_fde_index (), 39 m_fde_index_initialized (false), 40 m_is_eh_frame (is_eh_frame) 41 { 42 } 43 44 DWARFCallFrameInfo::~DWARFCallFrameInfo() 45 { 46 } 47 48 49 bool 50 DWARFCallFrameInfo::GetAddressRange (Address addr, AddressRange &range) 51 { 52 FDEEntry fde_entry; 53 if (GetFDEEntryByAddress (addr, fde_entry) == false) 54 return false; 55 range = fde_entry.bounds; 56 return true; 57 } 58 59 bool 60 DWARFCallFrameInfo::GetUnwindPlan (Address addr, UnwindPlan& unwind_plan) 61 { 62 FDEEntry fde_entry; 63 if (GetFDEEntryByAddress (addr, fde_entry) == false) 64 return false; 65 return FDEToUnwindPlan (fde_entry.offset, addr, unwind_plan); 66 } 67 68 bool 69 DWARFCallFrameInfo::GetFDEEntryByAddress (Address addr, FDEEntry& fde_entry) 70 { 71 if (m_section_sp.get() == NULL || m_section_sp->IsEncrypted()) 72 return false; 73 GetFDEIndex(); 74 75 struct FDEEntry searchfde; 76 searchfde.bounds = AddressRange (addr, 1); 77 78 std::vector<FDEEntry>::const_iterator idx; 79 if (m_fde_index.size() == 0) 80 return false; 81 82 idx = std::lower_bound (m_fde_index.begin(), m_fde_index.end(), searchfde); 83 if (idx == m_fde_index.end()) 84 { 85 --idx; 86 } 87 if (idx != m_fde_index.begin() && idx->bounds.GetBaseAddress().GetOffset() != addr.GetOffset()) 88 { 89 --idx; 90 } 91 if (idx->bounds.ContainsFileAddress (addr)) 92 { 93 fde_entry = *idx; 94 return true; 95 } 96 97 return false; 98 } 99 100 const DWARFCallFrameInfo::CIE* 101 DWARFCallFrameInfo::GetCIE(dw_offset_t cie_offset) 102 { 103 cie_map_t::iterator pos = m_cie_map.find(cie_offset); 104 105 if (pos != m_cie_map.end()) 106 { 107 // Parse and cache the CIE 108 if (pos->second.get() == NULL) 109 pos->second = ParseCIE (cie_offset); 110 111 return pos->second.get(); 112 } 113 return NULL; 114 } 115 116 DWARFCallFrameInfo::CIESP 117 DWARFCallFrameInfo::ParseCIE (const dw_offset_t cie_offset) 118 { 119 CIESP cie_sp(new CIE(cie_offset)); 120 dw_offset_t offset = cie_offset; 121 if (m_cfi_data_initialized == false) 122 GetCFIData(); 123 const uint32_t length = m_cfi_data.GetU32(&offset); 124 const dw_offset_t cie_id = m_cfi_data.GetU32(&offset); 125 const dw_offset_t end_offset = cie_offset + length + 4; 126 if (length > 0 && ((!m_is_eh_frame && cie_id == 0xfffffffful) || (m_is_eh_frame && cie_id == 0ul))) 127 { 128 size_t i; 129 // cie.offset = cie_offset; 130 // cie.length = length; 131 // cie.cieID = cieID; 132 cie_sp->ptr_encoding = DW_EH_PE_absptr; 133 cie_sp->version = m_cfi_data.GetU8(&offset); 134 135 for (i=0; i<CFI_AUG_MAX_SIZE; ++i) 136 { 137 cie_sp->augmentation[i] = m_cfi_data.GetU8(&offset); 138 if (cie_sp->augmentation[i] == '\0') 139 { 140 // Zero out remaining bytes in augmentation string 141 for (size_t j = i+1; j<CFI_AUG_MAX_SIZE; ++j) 142 cie_sp->augmentation[j] = '\0'; 143 144 break; 145 } 146 } 147 148 if (i == CFI_AUG_MAX_SIZE && cie_sp->augmentation[CFI_AUG_MAX_SIZE-1] != '\0') 149 { 150 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); 151 return cie_sp; 152 } 153 cie_sp->code_align = (uint32_t)m_cfi_data.GetULEB128(&offset); 154 cie_sp->data_align = (int32_t)m_cfi_data.GetSLEB128(&offset); 155 cie_sp->return_addr_reg_num = m_cfi_data.GetU8(&offset); 156 157 if (cie_sp->augmentation[0]) 158 { 159 // Get the length of the eh_frame augmentation data 160 // which starts with a ULEB128 length in bytes 161 const size_t aug_data_len = (size_t)m_cfi_data.GetULEB128(&offset); 162 const size_t aug_data_end = offset + aug_data_len; 163 const size_t aug_str_len = strlen(cie_sp->augmentation); 164 // A 'z' may be present as the first character of the string. 165 // If present, the Augmentation Data field shall be present. 166 // The contents of the Augmentation Data shall be intepreted 167 // according to other characters in the Augmentation String. 168 if (cie_sp->augmentation[0] == 'z') 169 { 170 // Extract the Augmentation Data 171 size_t aug_str_idx = 0; 172 for (aug_str_idx = 1; aug_str_idx < aug_str_len; aug_str_idx++) 173 { 174 char aug = cie_sp->augmentation[aug_str_idx]; 175 switch (aug) 176 { 177 case 'L': 178 // Indicates the presence of one argument in the 179 // Augmentation Data of the CIE, and a corresponding 180 // argument in the Augmentation Data of the FDE. The 181 // argument in the Augmentation Data of the CIE is 182 // 1-byte and represents the pointer encoding used 183 // for the argument in the Augmentation Data of the 184 // FDE, which is the address of a language-specific 185 // data area (LSDA). The size of the LSDA pointer is 186 // specified by the pointer encoding used. 187 m_cfi_data.GetU8(&offset); 188 break; 189 190 case 'P': 191 // Indicates the presence of two arguments in the 192 // Augmentation Data of the cie_sp-> The first argument 193 // is 1-byte and represents the pointer encoding 194 // used for the second argument, which is the 195 // address of a personality routine handler. The 196 // size of the personality routine pointer is 197 // specified by the pointer encoding used. 198 { 199 uint8_t arg_ptr_encoding = m_cfi_data.GetU8(&offset); 200 m_cfi_data.GetGNUEHPointer(&offset, arg_ptr_encoding, LLDB_INVALID_ADDRESS, LLDB_INVALID_ADDRESS, LLDB_INVALID_ADDRESS); 201 } 202 break; 203 204 case 'R': 205 // A 'R' may be present at any position after the 206 // first character of the string. The Augmentation 207 // Data shall include a 1 byte argument that 208 // represents the pointer encoding for the address 209 // pointers used in the FDE. 210 cie_sp->ptr_encoding = m_cfi_data.GetU8(&offset); 211 break; 212 } 213 } 214 } 215 else if (strcmp(cie_sp->augmentation, "eh") == 0) 216 { 217 // If the Augmentation string has the value "eh", then 218 // the EH Data field shall be present 219 } 220 221 // Set the offset to be the end of the augmentation data just in case 222 // we didn't understand any of the data. 223 offset = (uint32_t)aug_data_end; 224 } 225 226 if (end_offset > offset) 227 { 228 cie_sp->inst_offset = offset; 229 cie_sp->inst_length = end_offset - offset; 230 } 231 while (offset < end_offset) 232 { 233 uint8_t inst = m_cfi_data.GetU8(&offset); 234 uint8_t primary_opcode = inst & 0xC0; 235 uint8_t extended_opcode = inst & 0x3F; 236 237 if (extended_opcode == DW_CFA_def_cfa) 238 { 239 // Takes two unsigned LEB128 operands representing a register 240 // number and a (non-factored) offset. The required action 241 // is to define the current CFA rule to use the provided 242 // register and offset. 243 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 244 int op_offset = (int32_t)m_cfi_data.GetULEB128(&offset); 245 cie_sp->initial_row.SetCFARegister (reg_num); 246 cie_sp->initial_row.SetCFAOffset (op_offset); 247 continue; 248 } 249 if (primary_opcode == DW_CFA_offset) 250 { 251 // 0x80 - high 2 bits are 0x2, lower 6 bits are register. 252 // Takes two arguments: an unsigned LEB128 constant representing a 253 // factored offset and a register number. The required action is to 254 // change the rule for the register indicated by the register number 255 // to be an offset(N) rule with a value of 256 // (N = factored offset * data_align). 257 uint32_t reg_num = extended_opcode; 258 int op_offset = (int32_t)m_cfi_data.GetULEB128(&offset) * cie_sp->data_align; 259 UnwindPlan::Row::RegisterLocation reg_location; 260 reg_location.SetAtCFAPlusOffset(op_offset); 261 cie_sp->initial_row.SetRegisterInfo (reg_num, reg_location); 262 continue; 263 } 264 if (extended_opcode == DW_CFA_nop) 265 { 266 continue; 267 } 268 break; // Stop if we hit an unrecognized opcode 269 } 270 } 271 272 return cie_sp; 273 } 274 275 void 276 DWARFCallFrameInfo::GetCFIData() 277 { 278 if (m_cfi_data_initialized == false) 279 { 280 LogSP log(GetLogIfAllCategoriesSet (LIBLLDB_LOG_UNWIND)); 281 if (log) 282 m_objfile.GetModule()->LogMessage(log.get(), "Reading EH frame info"); 283 m_objfile.ReadSectionData (m_section_sp.get(), m_cfi_data); 284 m_cfi_data_initialized = true; 285 } 286 } 287 // Scan through the eh_frame or debug_frame section looking for FDEs and noting the start/end addresses 288 // of the functions and a pointer back to the function's FDE for later expansion. 289 // Internalize CIEs as we come across them. 290 291 void 292 DWARFCallFrameInfo::GetFDEIndex () 293 { 294 if (m_section_sp.get() == NULL || m_section_sp->IsEncrypted()) 295 return; 296 297 if (m_fde_index_initialized) 298 return; 299 300 Mutex::Locker locker(m_fde_index_mutex); 301 302 if (m_fde_index_initialized) // if two threads hit the locker 303 return; 304 305 dw_offset_t offset = 0; 306 if (m_cfi_data_initialized == false) 307 GetCFIData(); 308 while (m_cfi_data.ValidOffsetForDataOfSize (offset, 8)) 309 { 310 const dw_offset_t current_entry = offset; 311 uint32_t len = m_cfi_data.GetU32 (&offset); 312 dw_offset_t next_entry = current_entry + len + 4; 313 dw_offset_t cie_id = m_cfi_data.GetU32 (&offset); 314 315 if (cie_id == 0 || cie_id == UINT32_MAX) 316 { 317 m_cie_map[current_entry] = ParseCIE (current_entry); 318 offset = next_entry; 319 continue; 320 } 321 322 const dw_offset_t cie_offset = current_entry + 4 - cie_id; 323 const CIE *cie = GetCIE (cie_offset); 324 if (cie) 325 { 326 const lldb::addr_t pc_rel_addr = m_section_sp->GetFileAddress(); 327 const lldb::addr_t text_addr = LLDB_INVALID_ADDRESS; 328 const lldb::addr_t data_addr = LLDB_INVALID_ADDRESS; 329 330 lldb::addr_t addr = m_cfi_data.GetGNUEHPointer(&offset, cie->ptr_encoding, pc_rel_addr, text_addr, data_addr); 331 lldb::addr_t length = m_cfi_data.GetGNUEHPointer(&offset, cie->ptr_encoding & DW_EH_PE_MASK_ENCODING, pc_rel_addr, text_addr, data_addr); 332 FDEEntry fde; 333 fde.bounds = AddressRange (addr, length, m_objfile.GetSectionList()); 334 fde.offset = current_entry; 335 m_fde_index.push_back(fde); 336 } 337 else 338 { 339 Host::SystemLog (Host::eSystemLogError, 340 "error: unable to find CIE at 0x%8.8x for cie_id = 0x%8.8x for entry at 0x%8.8x.\n", 341 cie_offset, 342 cie_id, 343 current_entry); 344 } 345 offset = next_entry; 346 } 347 std::sort (m_fde_index.begin(), m_fde_index.end()); 348 m_fde_index_initialized = true; 349 } 350 351 bool 352 DWARFCallFrameInfo::FDEToUnwindPlan (dw_offset_t offset, Address startaddr, UnwindPlan& unwind_plan) 353 { 354 dw_offset_t current_entry = offset; 355 356 if (m_section_sp.get() == NULL || m_section_sp->IsEncrypted()) 357 return false; 358 359 if (m_cfi_data_initialized == false) 360 GetCFIData(); 361 362 uint32_t length = m_cfi_data.GetU32 (&offset); 363 dw_offset_t cie_offset = m_cfi_data.GetU32 (&offset); 364 365 assert (cie_offset != 0 && cie_offset != UINT32_MAX); 366 367 // Translate the CIE_id from the eh_frame format, which 368 // is relative to the FDE offset, into a __eh_frame section 369 // offset 370 if (m_is_eh_frame) 371 { 372 unwind_plan.SetSourceName ("eh_frame CFI"); 373 cie_offset = current_entry + 4 - cie_offset; 374 } 375 else 376 { 377 unwind_plan.SetSourceName ("DWARF CFI"); 378 } 379 380 const CIE *cie = GetCIE (cie_offset); 381 assert (cie != NULL); 382 383 const dw_offset_t end_offset = current_entry + length + 4; 384 385 const lldb::addr_t pc_rel_addr = m_section_sp->GetFileAddress(); 386 const lldb::addr_t text_addr = LLDB_INVALID_ADDRESS; 387 const lldb::addr_t data_addr = LLDB_INVALID_ADDRESS; 388 lldb::addr_t range_base = m_cfi_data.GetGNUEHPointer(&offset, cie->ptr_encoding, pc_rel_addr, text_addr, data_addr); 389 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); 390 AddressRange range (range_base, m_objfile.GetAddressByteSize(), m_objfile.GetSectionList()); 391 range.SetByteSize (range_len); 392 393 if (cie->augmentation[0] == 'z') 394 { 395 uint32_t aug_data_len = (uint32_t)m_cfi_data.GetULEB128(&offset); 396 offset += aug_data_len; 397 } 398 399 uint32_t reg_num = 0; 400 int32_t op_offset = 0; 401 uint32_t code_align = cie->code_align; 402 int32_t data_align = cie->data_align; 403 404 unwind_plan.SetPlanValidAddressRange (range); 405 UnwindPlan::Row *cie_initial_row = new UnwindPlan::Row; 406 *cie_initial_row = cie->initial_row; 407 UnwindPlan::RowSP row(cie_initial_row); 408 409 unwind_plan.SetRegisterKind (m_reg_kind); 410 unwind_plan.SetReturnAddressRegister (cie->return_addr_reg_num); 411 412 UnwindPlan::Row::RegisterLocation reg_location; 413 while (m_cfi_data.ValidOffset(offset) && offset < end_offset) 414 { 415 uint8_t inst = m_cfi_data.GetU8(&offset); 416 uint8_t primary_opcode = inst & 0xC0; 417 uint8_t extended_opcode = inst & 0x3F; 418 419 if (primary_opcode) 420 { 421 switch (primary_opcode) 422 { 423 case DW_CFA_advance_loc : // (Row Creation Instruction) 424 { // 0x40 - high 2 bits are 0x1, lower 6 bits are delta 425 // takes a single argument that represents a constant delta. The 426 // required action is to create a new table row with a location 427 // value that is computed by taking the current entry's location 428 // value and adding (delta * code_align). All other 429 // values in the new row are initially identical to the current row. 430 unwind_plan.AppendRow(row); 431 UnwindPlan::Row *newrow = new UnwindPlan::Row; 432 *newrow = *row.get(); 433 row.reset (newrow); 434 row->SlideOffset(extended_opcode * code_align); 435 } 436 break; 437 438 case DW_CFA_offset : 439 { // 0x80 - high 2 bits are 0x2, lower 6 bits are register 440 // takes two arguments: an unsigned LEB128 constant representing a 441 // factored offset and a register number. The required action is to 442 // change the rule for the register indicated by the register number 443 // to be an offset(N) rule with a value of 444 // (N = factored offset * data_align). 445 reg_num = extended_opcode; 446 op_offset = (int32_t)m_cfi_data.GetULEB128(&offset) * data_align; 447 reg_location.SetAtCFAPlusOffset(op_offset); 448 row->SetRegisterInfo (reg_num, reg_location); 449 } 450 break; 451 452 case DW_CFA_restore : 453 { // 0xC0 - high 2 bits are 0x3, lower 6 bits are register 454 // takes a single argument that represents a register number. The 455 // required action is to change the rule for the indicated register 456 // to the rule assigned it by the initial_instructions in the CIE. 457 reg_num = extended_opcode; 458 // We only keep enough register locations around to 459 // unwind what is in our thread, and these are organized 460 // by the register index in that state, so we need to convert our 461 // GCC register number from the EH frame info, to a register index 462 463 if (unwind_plan.IsValidRowIndex(0) && unwind_plan.GetRowAtIndex(0)->GetRegisterInfo(reg_num, reg_location)) 464 row->SetRegisterInfo (reg_num, reg_location); 465 } 466 break; 467 } 468 } 469 else 470 { 471 switch (extended_opcode) 472 { 473 case DW_CFA_nop : // 0x0 474 break; 475 476 case DW_CFA_set_loc : // 0x1 (Row Creation Instruction) 477 { 478 // DW_CFA_set_loc takes a single argument that represents an address. 479 // The required action is to create a new table row using the 480 // specified address as the location. All other values in the new row 481 // are initially identical to the current row. The new location value 482 // should always be greater than the current one. 483 unwind_plan.AppendRow(row); 484 UnwindPlan::Row *newrow = new UnwindPlan::Row; 485 *newrow = *row.get(); 486 row.reset (newrow); 487 row->SetOffset(m_cfi_data.GetPointer(&offset) - startaddr.GetFileAddress()); 488 } 489 break; 490 491 case DW_CFA_advance_loc1 : // 0x2 (Row Creation Instruction) 492 { 493 // takes a single uword argument that represents a constant delta. 494 // This instruction is identical to DW_CFA_advance_loc except for the 495 // encoding and size of the delta argument. 496 unwind_plan.AppendRow(row); 497 UnwindPlan::Row *newrow = new UnwindPlan::Row; 498 *newrow = *row.get(); 499 row.reset (newrow); 500 row->SlideOffset (m_cfi_data.GetU8(&offset) * code_align); 501 } 502 break; 503 504 case DW_CFA_advance_loc2 : // 0x3 (Row Creation Instruction) 505 { 506 // takes a single uword argument that represents a constant delta. 507 // This instruction is identical to DW_CFA_advance_loc except for the 508 // encoding and size of the delta argument. 509 unwind_plan.AppendRow(row); 510 UnwindPlan::Row *newrow = new UnwindPlan::Row; 511 *newrow = *row.get(); 512 row.reset (newrow); 513 row->SlideOffset (m_cfi_data.GetU16(&offset) * code_align); 514 } 515 break; 516 517 case DW_CFA_advance_loc4 : // 0x4 (Row Creation Instruction) 518 { 519 // takes a single uword argument that represents a constant delta. 520 // This instruction is identical to DW_CFA_advance_loc except for the 521 // encoding and size of the delta argument. 522 unwind_plan.AppendRow(row); 523 UnwindPlan::Row *newrow = new UnwindPlan::Row; 524 *newrow = *row.get(); 525 row.reset (newrow); 526 row->SlideOffset (m_cfi_data.GetU32(&offset) * code_align); 527 } 528 break; 529 530 case DW_CFA_offset_extended : // 0x5 531 { 532 // takes two unsigned LEB128 arguments representing a register number 533 // and a factored offset. This instruction is identical to DW_CFA_offset 534 // except for the encoding and size of the register argument. 535 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 536 op_offset = (int32_t)m_cfi_data.GetULEB128(&offset) * data_align; 537 reg_location.SetAtCFAPlusOffset(op_offset); 538 row->SetRegisterInfo (reg_num, reg_location); 539 } 540 break; 541 542 case DW_CFA_restore_extended : // 0x6 543 { 544 // takes a single unsigned LEB128 argument that represents a register 545 // number. This instruction is identical to DW_CFA_restore except for 546 // the encoding and size of the register argument. 547 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 548 if (unwind_plan.IsValidRowIndex(0) && unwind_plan.GetRowAtIndex(0)->GetRegisterInfo(reg_num, reg_location)) 549 row->SetRegisterInfo (reg_num, reg_location); 550 } 551 break; 552 553 case DW_CFA_undefined : // 0x7 554 { 555 // takes a single unsigned LEB128 argument that represents a register 556 // number. The required action is to set the rule for the specified 557 // register to undefined. 558 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 559 reg_location.SetUndefined(); 560 row->SetRegisterInfo (reg_num, reg_location); 561 } 562 break; 563 564 case DW_CFA_same_value : // 0x8 565 { 566 // takes a single unsigned LEB128 argument that represents a register 567 // number. The required action is to set the rule for the specified 568 // register to same value. 569 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 570 reg_location.SetSame(); 571 row->SetRegisterInfo (reg_num, reg_location); 572 } 573 break; 574 575 case DW_CFA_register : // 0x9 576 { 577 // takes two unsigned LEB128 arguments representing register numbers. 578 // The required action is to set the rule for the first register to be 579 // the second register. 580 581 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 582 uint32_t other_reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 583 reg_location.SetInRegister(other_reg_num); 584 row->SetRegisterInfo (reg_num, reg_location); 585 } 586 break; 587 588 case DW_CFA_remember_state : // 0xA 589 { 590 // These instructions define a stack of information. Encountering the 591 // DW_CFA_remember_state instruction means to save the rules for every 592 // register on the current row on the stack. Encountering the 593 // DW_CFA_restore_state instruction means to pop the set of rules off 594 // the stack and place them in the current row. (This operation is 595 // useful for compilers that move epilogue code into the body of a 596 // function.) 597 unwind_plan.AppendRow (row); 598 UnwindPlan::Row *newrow = new UnwindPlan::Row; 599 *newrow = *row.get(); 600 row.reset (newrow); 601 } 602 break; 603 604 case DW_CFA_restore_state : // 0xB 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 { 613 row = unwind_plan.GetRowAtIndex(unwind_plan.GetRowCount() - 1); 614 } 615 break; 616 617 case DW_CFA_def_cfa : // 0xC (CFA Definition Instruction) 618 { 619 // Takes two unsigned LEB128 operands representing a register 620 // number and a (non-factored) offset. The required action 621 // is to define the current CFA rule to use the provided 622 // register and offset. 623 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 624 op_offset = (int32_t)m_cfi_data.GetULEB128(&offset); 625 row->SetCFARegister (reg_num); 626 row->SetCFAOffset (op_offset); 627 } 628 break; 629 630 case DW_CFA_def_cfa_register : // 0xD (CFA Definition Instruction) 631 { 632 // takes a single unsigned LEB128 argument representing a register 633 // number. The required action is to define the current CFA rule to 634 // use the provided register (but to keep the old offset). 635 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 636 row->SetCFARegister (reg_num); 637 } 638 break; 639 640 case DW_CFA_def_cfa_offset : // 0xE (CFA Definition Instruction) 641 { 642 // Takes a single unsigned LEB128 operand representing a 643 // (non-factored) offset. The required action is to define 644 // the current CFA rule to use the provided offset (but 645 // to keep the old register). 646 op_offset = (int32_t)m_cfi_data.GetULEB128(&offset); 647 row->SetCFAOffset (op_offset); 648 } 649 break; 650 651 case DW_CFA_def_cfa_expression : // 0xF (CFA Definition Instruction) 652 { 653 size_t block_len = (size_t)m_cfi_data.GetULEB128(&offset); 654 offset += (uint32_t)block_len; 655 } 656 break; 657 658 case DW_CFA_expression : // 0x10 659 { 660 // Takes two operands: an unsigned LEB128 value representing 661 // a register number, and a DW_FORM_block value representing a DWARF 662 // expression. The required action is to change the rule for the 663 // register indicated by the register number to be an expression(E) 664 // rule where E is the DWARF expression. That is, the DWARF 665 // expression computes the address. The value of the CFA is 666 // pushed on the DWARF evaluation stack prior to execution of 667 // the DWARF expression. 668 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 669 uint32_t block_len = (uint32_t)m_cfi_data.GetULEB128(&offset); 670 const uint8_t *block_data = (uint8_t *)m_cfi_data.GetData(&offset, block_len); 671 672 reg_location.SetAtDWARFExpression(block_data, block_len); 673 row->SetRegisterInfo (reg_num, reg_location); 674 } 675 break; 676 677 case DW_CFA_offset_extended_sf : // 0x11 678 { 679 // takes two operands: an unsigned LEB128 value representing a 680 // register number and a signed LEB128 factored offset. This 681 // instruction is identical to DW_CFA_offset_extended except 682 //that the second operand is signed and factored. 683 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 684 op_offset = (int32_t)m_cfi_data.GetSLEB128(&offset) * data_align; 685 reg_location.SetAtCFAPlusOffset(op_offset); 686 row->SetRegisterInfo (reg_num, reg_location); 687 } 688 break; 689 690 case DW_CFA_def_cfa_sf : // 0x12 (CFA Definition Instruction) 691 { 692 // Takes two operands: an unsigned LEB128 value representing 693 // a register number and a signed LEB128 factored offset. 694 // This instruction is identical to DW_CFA_def_cfa except 695 // that the second operand is signed and factored. 696 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 697 op_offset = (int32_t)m_cfi_data.GetSLEB128(&offset) * data_align; 698 row->SetCFARegister (reg_num); 699 row->SetCFAOffset (op_offset); 700 } 701 break; 702 703 case DW_CFA_def_cfa_offset_sf : // 0x13 (CFA Definition Instruction) 704 { 705 // takes a signed LEB128 operand representing a factored 706 // offset. This instruction is identical to DW_CFA_def_cfa_offset 707 // except that the operand is signed and factored. 708 op_offset = (int32_t)m_cfi_data.GetSLEB128(&offset) * data_align; 709 row->SetCFAOffset (op_offset); 710 } 711 break; 712 713 case DW_CFA_val_expression : // 0x16 714 { 715 // takes two operands: an unsigned LEB128 value representing a register 716 // number, and a DW_FORM_block value representing a DWARF expression. 717 // The required action is to change the rule for the register indicated 718 // by the register number to be a val_expression(E) rule where E is the 719 // DWARF expression. That is, the DWARF expression computes the value of 720 // the given register. The value of the CFA is pushed on the DWARF 721 // evaluation stack prior to execution of the DWARF expression. 722 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 723 uint32_t block_len = (uint32_t)m_cfi_data.GetULEB128(&offset); 724 const uint8_t* block_data = (uint8_t*)m_cfi_data.GetData(&offset, block_len); 725 //#if defined(__i386__) || defined(__x86_64__) 726 // // The EH frame info for EIP and RIP contains code that looks for traps to 727 // // be a specific type and increments the PC. 728 // // For i386: 729 // // DW_CFA_val_expression where: 730 // // eip = DW_OP_breg6(+28), DW_OP_deref, DW_OP_dup, DW_OP_plus_uconst(0x34), 731 // // DW_OP_deref, DW_OP_swap, DW_OP_plus_uconst(0), DW_OP_deref, 732 // // DW_OP_dup, DW_OP_lit3, DW_OP_ne, DW_OP_swap, DW_OP_lit4, DW_OP_ne, 733 // // DW_OP_and, DW_OP_plus 734 // // This basically does a: 735 // // eip = ucontenxt.mcontext32->gpr.eip; 736 // // if (ucontenxt.mcontext32->exc.trapno != 3 && ucontenxt.mcontext32->exc.trapno != 4) 737 // // eip++; 738 // // 739 // // For x86_64: 740 // // DW_CFA_val_expression where: 741 // // rip = DW_OP_breg3(+48), DW_OP_deref, DW_OP_dup, DW_OP_plus_uconst(0x90), DW_OP_deref, 742 // // DW_OP_swap, DW_OP_plus_uconst(0), DW_OP_deref_size(4), DW_OP_dup, DW_OP_lit3, 743 // // DW_OP_ne, DW_OP_swap, DW_OP_lit4, DW_OP_ne, DW_OP_and, DW_OP_plus 744 // // This basically does a: 745 // // rip = ucontenxt.mcontext64->gpr.rip; 746 // // if (ucontenxt.mcontext64->exc.trapno != 3 && ucontenxt.mcontext64->exc.trapno != 4) 747 // // rip++; 748 // // The trap comparisons and increments are not needed as it hoses up the unwound PC which 749 // // is expected to point at least past the instruction that causes the fault/trap. So we 750 // // take it out by trimming the expression right at the first "DW_OP_swap" opcodes 751 // if (block_data != NULL && thread->GetPCRegNum(Thread::GCC) == reg_num) 752 // { 753 // if (thread->Is64Bit()) 754 // { 755 // if (block_len > 9 && block_data[8] == DW_OP_swap && block_data[9] == DW_OP_plus_uconst) 756 // block_len = 8; 757 // } 758 // else 759 // { 760 // if (block_len > 8 && block_data[7] == DW_OP_swap && block_data[8] == DW_OP_plus_uconst) 761 // block_len = 7; 762 // } 763 // } 764 //#endif 765 reg_location.SetIsDWARFExpression(block_data, block_len); 766 row->SetRegisterInfo (reg_num, reg_location); 767 } 768 break; 769 770 case DW_CFA_val_offset : // 0x14 771 case DW_CFA_val_offset_sf : // 0x15 772 default: 773 break; 774 } 775 } 776 } 777 unwind_plan.AppendRow(row); 778 779 return true; 780 } 781