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 28using namespace lldb; 29using namespace lldb_private; 30 31DWARFCallFrameInfo::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 45DWARFCallFrameInfo::~DWARFCallFrameInfo() 46{ 47} 48 49 50bool 51DWARFCallFrameInfo::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 66bool 67DWARFCallFrameInfo::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 87bool 88DWARFCallFrameInfo::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 107void 108DWARFCallFrameInfo::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 126const DWARFCallFrameInfo::CIE* 127DWARFCallFrameInfo::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() == NULL) 135 pos->second = ParseCIE (cie_offset); 136 137 return pos->second.get(); 138 } 139 return NULL; 140} 141 142DWARFCallFrameInfo::CIESP 143DWARFCallFrameInfo::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 const uint32_t length = m_cfi_data.GetU32(&offset); 150 const dw_offset_t cie_id = m_cfi_data.GetU32(&offset); 151 const dw_offset_t end_offset = cie_offset + length + 4; 152 if (length > 0 && ((!m_is_eh_frame && cie_id == UINT32_MAX) || (m_is_eh_frame && cie_id == 0ul))) 153 { 154 size_t i; 155 // cie.offset = cie_offset; 156 // cie.length = length; 157 // cie.cieID = cieID; 158 cie_sp->ptr_encoding = DW_EH_PE_absptr; // default 159 cie_sp->version = m_cfi_data.GetU8(&offset); 160 161 for (i=0; i<CFI_AUG_MAX_SIZE; ++i) 162 { 163 cie_sp->augmentation[i] = m_cfi_data.GetU8(&offset); 164 if (cie_sp->augmentation[i] == '\0') 165 { 166 // Zero out remaining bytes in augmentation string 167 for (size_t j = i+1; j<CFI_AUG_MAX_SIZE; ++j) 168 cie_sp->augmentation[j] = '\0'; 169 170 break; 171 } 172 } 173 174 if (i == CFI_AUG_MAX_SIZE && cie_sp->augmentation[CFI_AUG_MAX_SIZE-1] != '\0') 175 { 176 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); 177 return cie_sp; 178 } 179 cie_sp->code_align = (uint32_t)m_cfi_data.GetULEB128(&offset); 180 cie_sp->data_align = (int32_t)m_cfi_data.GetSLEB128(&offset); 181 cie_sp->return_addr_reg_num = m_cfi_data.GetU8(&offset); 182 183 if (cie_sp->augmentation[0]) 184 { 185 // Get the length of the eh_frame augmentation data 186 // which starts with a ULEB128 length in bytes 187 const size_t aug_data_len = (size_t)m_cfi_data.GetULEB128(&offset); 188 const size_t aug_data_end = offset + aug_data_len; 189 const size_t aug_str_len = strlen(cie_sp->augmentation); 190 // A 'z' may be present as the first character of the string. 191 // If present, the Augmentation Data field shall be present. 192 // The contents of the Augmentation Data shall be intepreted 193 // according to other characters in the Augmentation String. 194 if (cie_sp->augmentation[0] == 'z') 195 { 196 // Extract the Augmentation Data 197 size_t aug_str_idx = 0; 198 for (aug_str_idx = 1; aug_str_idx < aug_str_len; aug_str_idx++) 199 { 200 char aug = cie_sp->augmentation[aug_str_idx]; 201 switch (aug) 202 { 203 case 'L': 204 // Indicates the presence of one argument in the 205 // Augmentation Data of the CIE, and a corresponding 206 // argument in the Augmentation Data of the FDE. The 207 // argument in the Augmentation Data of the CIE is 208 // 1-byte and represents the pointer encoding used 209 // for the argument in the Augmentation Data of the 210 // FDE, which is the address of a language-specific 211 // data area (LSDA). The size of the LSDA pointer is 212 // specified by the pointer encoding used. 213 m_cfi_data.GetU8(&offset); 214 break; 215 216 case 'P': 217 // Indicates the presence of two arguments in the 218 // Augmentation Data of the cie_sp-> The first argument 219 // is 1-byte and represents the pointer encoding 220 // used for the second argument, which is the 221 // address of a personality routine handler. The 222 // size of the personality routine pointer is 223 // specified by the pointer encoding used. 224 { 225 uint8_t arg_ptr_encoding = m_cfi_data.GetU8(&offset); 226 m_cfi_data.GetGNUEHPointer(&offset, arg_ptr_encoding, LLDB_INVALID_ADDRESS, LLDB_INVALID_ADDRESS, LLDB_INVALID_ADDRESS); 227 } 228 break; 229 230 case 'R': 231 // A 'R' may be present at any position after the 232 // first character of the string. The Augmentation 233 // Data shall include a 1 byte argument that 234 // represents the pointer encoding for the address 235 // pointers used in the FDE. 236 // Example: 0x1B == DW_EH_PE_pcrel | DW_EH_PE_sdata4 237 cie_sp->ptr_encoding = m_cfi_data.GetU8(&offset); 238 break; 239 } 240 } 241 } 242 else if (strcmp(cie_sp->augmentation, "eh") == 0) 243 { 244 // If the Augmentation string has the value "eh", then 245 // the EH Data field shall be present 246 } 247 248 // Set the offset to be the end of the augmentation data just in case 249 // we didn't understand any of the data. 250 offset = (uint32_t)aug_data_end; 251 } 252 253 if (end_offset > offset) 254 { 255 cie_sp->inst_offset = offset; 256 cie_sp->inst_length = end_offset - offset; 257 } 258 while (offset < end_offset) 259 { 260 uint8_t inst = m_cfi_data.GetU8(&offset); 261 uint8_t primary_opcode = inst & 0xC0; 262 uint8_t extended_opcode = inst & 0x3F; 263 264 if (extended_opcode == DW_CFA_def_cfa) 265 { 266 // Takes two unsigned LEB128 operands representing a register 267 // number and a (non-factored) offset. The required action 268 // is to define the current CFA rule to use the provided 269 // register and offset. 270 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 271 int op_offset = (int32_t)m_cfi_data.GetULEB128(&offset); 272 cie_sp->initial_row.SetCFARegister (reg_num); 273 cie_sp->initial_row.SetCFAOffset (op_offset); 274 continue; 275 } 276 if (primary_opcode == DW_CFA_offset) 277 { 278 // 0x80 - high 2 bits are 0x2, lower 6 bits are register. 279 // Takes two arguments: an unsigned LEB128 constant representing a 280 // factored offset and a register number. The required action is to 281 // change the rule for the register indicated by the register number 282 // to be an offset(N) rule with a value of 283 // (N = factored offset * data_align). 284 uint32_t reg_num = extended_opcode; 285 int op_offset = (int32_t)m_cfi_data.GetULEB128(&offset) * cie_sp->data_align; 286 UnwindPlan::Row::RegisterLocation reg_location; 287 reg_location.SetAtCFAPlusOffset(op_offset); 288 cie_sp->initial_row.SetRegisterInfo (reg_num, reg_location); 289 continue; 290 } 291 if (extended_opcode == DW_CFA_nop) 292 { 293 continue; 294 } 295 break; // Stop if we hit an unrecognized opcode 296 } 297 } 298 299 return cie_sp; 300} 301 302void 303DWARFCallFrameInfo::GetCFIData() 304{ 305 if (m_cfi_data_initialized == false) 306 { 307 Log *log(GetLogIfAllCategoriesSet (LIBLLDB_LOG_UNWIND)); 308 if (log) 309 m_objfile.GetModule()->LogMessage(log, "Reading EH frame info"); 310 m_objfile.ReadSectionData (m_section_sp.get(), m_cfi_data); 311 m_cfi_data_initialized = true; 312 } 313} 314// Scan through the eh_frame or debug_frame section looking for FDEs and noting the start/end addresses 315// of the functions and a pointer back to the function's FDE for later expansion. 316// Internalize CIEs as we come across them. 317 318void 319DWARFCallFrameInfo::GetFDEIndex () 320{ 321 if (m_section_sp.get() == NULL || m_section_sp->IsEncrypted()) 322 return; 323 324 if (m_fde_index_initialized) 325 return; 326 327 Mutex::Locker locker(m_fde_index_mutex); 328 329 if (m_fde_index_initialized) // if two threads hit the locker 330 return; 331 332 Timer scoped_timer (__PRETTY_FUNCTION__, "%s - %s", __PRETTY_FUNCTION__, m_objfile.GetFileSpec().GetFilename().AsCString("")); 333 334 lldb::offset_t offset = 0; 335 if (m_cfi_data_initialized == false) 336 GetCFIData(); 337 while (m_cfi_data.ValidOffsetForDataOfSize (offset, 8)) 338 { 339 const dw_offset_t current_entry = offset; 340 uint32_t len = m_cfi_data.GetU32 (&offset); 341 dw_offset_t next_entry = current_entry + len + 4; 342 dw_offset_t cie_id = m_cfi_data.GetU32 (&offset); 343 344 if (cie_id == 0 || cie_id == UINT32_MAX || len == 0) 345 { 346 m_cie_map[current_entry] = ParseCIE (current_entry); 347 offset = next_entry; 348 continue; 349 } 350 351 const dw_offset_t cie_offset = current_entry + 4 - cie_id; 352 const CIE *cie = GetCIE (cie_offset); 353 if (cie) 354 { 355 const lldb::addr_t pc_rel_addr = m_section_sp->GetFileAddress(); 356 const lldb::addr_t text_addr = LLDB_INVALID_ADDRESS; 357 const lldb::addr_t data_addr = LLDB_INVALID_ADDRESS; 358 359 lldb::addr_t addr = m_cfi_data.GetGNUEHPointer(&offset, cie->ptr_encoding, pc_rel_addr, text_addr, data_addr); 360 lldb::addr_t length = m_cfi_data.GetGNUEHPointer(&offset, cie->ptr_encoding & DW_EH_PE_MASK_ENCODING, pc_rel_addr, text_addr, data_addr); 361 FDEEntryMap::Entry fde (addr, length, current_entry); 362 m_fde_index.Append(fde); 363 } 364 else 365 { 366 Host::SystemLog (Host::eSystemLogError, 367 "error: unable to find CIE at 0x%8.8x for cie_id = 0x%8.8x for entry at 0x%8.8x.\n", 368 cie_offset, 369 cie_id, 370 current_entry); 371 } 372 offset = next_entry; 373 } 374 m_fde_index.Sort(); 375 m_fde_index_initialized = true; 376} 377 378bool 379DWARFCallFrameInfo::FDEToUnwindPlan (dw_offset_t dwarf_offset, Address startaddr, UnwindPlan& unwind_plan) 380{ 381 lldb::offset_t offset = dwarf_offset; 382 lldb::offset_t current_entry = offset; 383 384 if (m_section_sp.get() == NULL || m_section_sp->IsEncrypted()) 385 return false; 386 387 if (m_cfi_data_initialized == false) 388 GetCFIData(); 389 390 uint32_t length = m_cfi_data.GetU32 (&offset); 391 dw_offset_t cie_offset = m_cfi_data.GetU32 (&offset); 392 393 assert (cie_offset != 0 && cie_offset != UINT32_MAX); 394 395 // Translate the CIE_id from the eh_frame format, which 396 // is relative to the FDE offset, into a __eh_frame section 397 // offset 398 if (m_is_eh_frame) 399 { 400 unwind_plan.SetSourceName ("eh_frame CFI"); 401 cie_offset = current_entry + 4 - cie_offset; 402 unwind_plan.SetUnwindPlanValidAtAllInstructions (eLazyBoolNo); 403 } 404 else 405 { 406 unwind_plan.SetSourceName ("DWARF CFI"); 407 // In theory the debug_frame info should be valid at all call sites 408 // ("asynchronous unwind info" as it is sometimes called) but in practice 409 // gcc et al all emit call frame info for the prologue and call sites, but 410 // not for the epilogue or all the other locations during the function reliably. 411 unwind_plan.SetUnwindPlanValidAtAllInstructions (eLazyBoolNo); 412 } 413 unwind_plan.SetSourcedFromCompiler (eLazyBoolYes); 414 415 const CIE *cie = GetCIE (cie_offset); 416 assert (cie != NULL); 417 418 const dw_offset_t end_offset = current_entry + length + 4; 419 420 const lldb::addr_t pc_rel_addr = m_section_sp->GetFileAddress(); 421 const lldb::addr_t text_addr = LLDB_INVALID_ADDRESS; 422 const lldb::addr_t data_addr = LLDB_INVALID_ADDRESS; 423 lldb::addr_t range_base = m_cfi_data.GetGNUEHPointer(&offset, cie->ptr_encoding, pc_rel_addr, text_addr, data_addr); 424 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); 425 AddressRange range (range_base, m_objfile.GetAddressByteSize(), m_objfile.GetSectionList()); 426 range.SetByteSize (range_len); 427 428 if (cie->augmentation[0] == 'z') 429 { 430 uint32_t aug_data_len = (uint32_t)m_cfi_data.GetULEB128(&offset); 431 offset += aug_data_len; 432 } 433 434 uint32_t reg_num = 0; 435 int32_t op_offset = 0; 436 uint32_t code_align = cie->code_align; 437 int32_t data_align = cie->data_align; 438 439 unwind_plan.SetPlanValidAddressRange (range); 440 UnwindPlan::Row *cie_initial_row = new UnwindPlan::Row; 441 *cie_initial_row = cie->initial_row; 442 UnwindPlan::RowSP row(cie_initial_row); 443 444 unwind_plan.SetRegisterKind (m_reg_kind); 445 unwind_plan.SetReturnAddressRegister (cie->return_addr_reg_num); 446 447 std::vector<UnwindPlan::RowSP> stack; 448 449 UnwindPlan::Row::RegisterLocation reg_location; 450 while (m_cfi_data.ValidOffset(offset) && offset < end_offset) 451 { 452 uint8_t inst = m_cfi_data.GetU8(&offset); 453 uint8_t primary_opcode = inst & 0xC0; 454 uint8_t extended_opcode = inst & 0x3F; 455 456 if (primary_opcode) 457 { 458 switch (primary_opcode) 459 { 460 case DW_CFA_advance_loc : // (Row Creation Instruction) 461 { // 0x40 - high 2 bits are 0x1, lower 6 bits are delta 462 // takes a single argument that represents a constant delta. The 463 // required action is to create a new table row with a location 464 // value that is computed by taking the current entry's location 465 // value and adding (delta * code_align). All other 466 // values in the new row are initially identical to the current row. 467 unwind_plan.AppendRow(row); 468 UnwindPlan::Row *newrow = new UnwindPlan::Row; 469 *newrow = *row.get(); 470 row.reset (newrow); 471 row->SlideOffset(extended_opcode * code_align); 472 } 473 break; 474 475 case DW_CFA_offset : 476 { // 0x80 - high 2 bits are 0x2, lower 6 bits are register 477 // takes two arguments: an unsigned LEB128 constant representing a 478 // factored offset and a register number. The required action is to 479 // change the rule for the register indicated by the register number 480 // to be an offset(N) rule with a value of 481 // (N = factored offset * data_align). 482 reg_num = extended_opcode; 483 op_offset = (int32_t)m_cfi_data.GetULEB128(&offset) * data_align; 484 reg_location.SetAtCFAPlusOffset(op_offset); 485 row->SetRegisterInfo (reg_num, reg_location); 486 } 487 break; 488 489 case DW_CFA_restore : 490 { // 0xC0 - high 2 bits are 0x3, lower 6 bits are register 491 // takes a single argument that represents a register number. The 492 // required action is to change the rule for the indicated register 493 // to the rule assigned it by the initial_instructions in the CIE. 494 reg_num = extended_opcode; 495 // We only keep enough register locations around to 496 // unwind what is in our thread, and these are organized 497 // by the register index in that state, so we need to convert our 498 // GCC register number from the EH frame info, to a register index 499 500 if (unwind_plan.IsValidRowIndex(0) && unwind_plan.GetRowAtIndex(0)->GetRegisterInfo(reg_num, reg_location)) 501 row->SetRegisterInfo (reg_num, reg_location); 502 } 503 break; 504 } 505 } 506 else 507 { 508 switch (extended_opcode) 509 { 510 case DW_CFA_nop : // 0x0 511 break; 512 513 case DW_CFA_set_loc : // 0x1 (Row Creation Instruction) 514 { 515 // DW_CFA_set_loc takes a single argument that represents an address. 516 // The required action is to create a new table row using the 517 // specified address as the location. All other values in the new row 518 // are initially identical to the current row. The new location value 519 // should always be greater than the current one. 520 unwind_plan.AppendRow(row); 521 UnwindPlan::Row *newrow = new UnwindPlan::Row; 522 *newrow = *row.get(); 523 row.reset (newrow); 524 row->SetOffset(m_cfi_data.GetPointer(&offset) - startaddr.GetFileAddress()); 525 } 526 break; 527 528 case DW_CFA_advance_loc1 : // 0x2 (Row Creation Instruction) 529 { 530 // takes a single uword argument that represents a constant delta. 531 // This instruction is identical to DW_CFA_advance_loc except for the 532 // encoding and size of the delta argument. 533 unwind_plan.AppendRow(row); 534 UnwindPlan::Row *newrow = new UnwindPlan::Row; 535 *newrow = *row.get(); 536 row.reset (newrow); 537 row->SlideOffset (m_cfi_data.GetU8(&offset) * code_align); 538 } 539 break; 540 541 case DW_CFA_advance_loc2 : // 0x3 (Row Creation Instruction) 542 { 543 // takes a single uword argument that represents a constant delta. 544 // This instruction is identical to DW_CFA_advance_loc except for the 545 // encoding and size of the delta argument. 546 unwind_plan.AppendRow(row); 547 UnwindPlan::Row *newrow = new UnwindPlan::Row; 548 *newrow = *row.get(); 549 row.reset (newrow); 550 row->SlideOffset (m_cfi_data.GetU16(&offset) * code_align); 551 } 552 break; 553 554 case DW_CFA_advance_loc4 : // 0x4 (Row Creation Instruction) 555 { 556 // takes a single uword argument that represents a constant delta. 557 // This instruction is identical to DW_CFA_advance_loc except for the 558 // encoding and size of the delta argument. 559 unwind_plan.AppendRow(row); 560 UnwindPlan::Row *newrow = new UnwindPlan::Row; 561 *newrow = *row.get(); 562 row.reset (newrow); 563 row->SlideOffset (m_cfi_data.GetU32(&offset) * code_align); 564 } 565 break; 566 567 case DW_CFA_offset_extended : // 0x5 568 { 569 // takes two unsigned LEB128 arguments representing a register number 570 // and a factored offset. This instruction is identical to DW_CFA_offset 571 // except for the encoding and size of the register argument. 572 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 573 op_offset = (int32_t)m_cfi_data.GetULEB128(&offset) * data_align; 574 reg_location.SetAtCFAPlusOffset(op_offset); 575 row->SetRegisterInfo (reg_num, reg_location); 576 } 577 break; 578 579 case DW_CFA_restore_extended : // 0x6 580 { 581 // takes a single unsigned LEB128 argument that represents a register 582 // number. This instruction is identical to DW_CFA_restore except for 583 // the encoding and size of the register argument. 584 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 585 if (unwind_plan.IsValidRowIndex(0) && unwind_plan.GetRowAtIndex(0)->GetRegisterInfo(reg_num, reg_location)) 586 row->SetRegisterInfo (reg_num, reg_location); 587 } 588 break; 589 590 case DW_CFA_undefined : // 0x7 591 { 592 // takes a single unsigned LEB128 argument that represents a register 593 // number. The required action is to set the rule for the specified 594 // register to undefined. 595 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 596 reg_location.SetUndefined(); 597 row->SetRegisterInfo (reg_num, reg_location); 598 } 599 break; 600 601 case DW_CFA_same_value : // 0x8 602 { 603 // takes a single unsigned LEB128 argument that represents a register 604 // number. The required action is to set the rule for the specified 605 // register to same value. 606 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 607 reg_location.SetSame(); 608 row->SetRegisterInfo (reg_num, reg_location); 609 } 610 break; 611 612 case DW_CFA_register : // 0x9 613 { 614 // takes two unsigned LEB128 arguments representing register numbers. 615 // The required action is to set the rule for the first register to be 616 // the second register. 617 618 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 619 uint32_t other_reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 620 reg_location.SetInRegister(other_reg_num); 621 row->SetRegisterInfo (reg_num, reg_location); 622 } 623 break; 624 625 case DW_CFA_remember_state : // 0xA 626 { 627 // These instructions define a stack of information. Encountering the 628 // DW_CFA_remember_state instruction means to save the rules for every 629 // register on the current row on the stack. Encountering the 630 // DW_CFA_restore_state instruction means to pop the set of rules off 631 // the stack and place them in the current row. (This operation is 632 // useful for compilers that move epilogue code into the body of a 633 // function.) 634 stack.push_back (row); 635 UnwindPlan::Row *newrow = new UnwindPlan::Row; 636 *newrow = *row.get(); 637 row.reset (newrow); 638 } 639 break; 640 641 case DW_CFA_restore_state : // 0xB 642 // These instructions define a stack of information. Encountering the 643 // DW_CFA_remember_state instruction means to save the rules for every 644 // register on the current row on the stack. Encountering the 645 // DW_CFA_restore_state instruction means to pop the set of rules off 646 // the stack and place them in the current row. (This operation is 647 // useful for compilers that move epilogue code into the body of a 648 // function.) 649 { 650 row = stack.back (); 651 stack.pop_back (); 652 } 653 break; 654 655 case DW_CFA_def_cfa : // 0xC (CFA Definition Instruction) 656 { 657 // Takes two unsigned LEB128 operands representing a register 658 // number and a (non-factored) offset. The required action 659 // is to define the current CFA rule to use the provided 660 // register and offset. 661 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 662 op_offset = (int32_t)m_cfi_data.GetULEB128(&offset); 663 row->SetCFARegister (reg_num); 664 row->SetCFAOffset (op_offset); 665 } 666 break; 667 668 case DW_CFA_def_cfa_register : // 0xD (CFA Definition Instruction) 669 { 670 // takes a single unsigned LEB128 argument representing a register 671 // number. The required action is to define the current CFA rule to 672 // use the provided register (but to keep the old offset). 673 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 674 row->SetCFARegister (reg_num); 675 } 676 break; 677 678 case DW_CFA_def_cfa_offset : // 0xE (CFA Definition Instruction) 679 { 680 // Takes a single unsigned LEB128 operand representing a 681 // (non-factored) offset. The required action is to define 682 // the current CFA rule to use the provided offset (but 683 // to keep the old register). 684 op_offset = (int32_t)m_cfi_data.GetULEB128(&offset); 685 row->SetCFAOffset (op_offset); 686 } 687 break; 688 689 case DW_CFA_def_cfa_expression : // 0xF (CFA Definition Instruction) 690 { 691 size_t block_len = (size_t)m_cfi_data.GetULEB128(&offset); 692 offset += (uint32_t)block_len; 693 } 694 break; 695 696 case DW_CFA_expression : // 0x10 697 { 698 // Takes two operands: an unsigned LEB128 value representing 699 // a register number, and a DW_FORM_block value representing a DWARF 700 // expression. The required action is to change the rule for the 701 // register indicated by the register number to be an expression(E) 702 // rule where E is the DWARF expression. That is, the DWARF 703 // expression computes the address. The value of the CFA is 704 // pushed on the DWARF evaluation stack prior to execution of 705 // the DWARF expression. 706 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 707 uint32_t block_len = (uint32_t)m_cfi_data.GetULEB128(&offset); 708 const uint8_t *block_data = (uint8_t *)m_cfi_data.GetData(&offset, block_len); 709 710 reg_location.SetAtDWARFExpression(block_data, block_len); 711 row->SetRegisterInfo (reg_num, reg_location); 712 } 713 break; 714 715 case DW_CFA_offset_extended_sf : // 0x11 716 { 717 // takes two operands: an unsigned LEB128 value representing a 718 // register number and a signed LEB128 factored offset. This 719 // instruction is identical to DW_CFA_offset_extended except 720 //that the second operand is signed and factored. 721 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 722 op_offset = (int32_t)m_cfi_data.GetSLEB128(&offset) * data_align; 723 reg_location.SetAtCFAPlusOffset(op_offset); 724 row->SetRegisterInfo (reg_num, reg_location); 725 } 726 break; 727 728 case DW_CFA_def_cfa_sf : // 0x12 (CFA Definition Instruction) 729 { 730 // Takes two operands: an unsigned LEB128 value representing 731 // a register number and a signed LEB128 factored offset. 732 // This instruction is identical to DW_CFA_def_cfa except 733 // that the second operand is signed and factored. 734 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 735 op_offset = (int32_t)m_cfi_data.GetSLEB128(&offset) * data_align; 736 row->SetCFARegister (reg_num); 737 row->SetCFAOffset (op_offset); 738 } 739 break; 740 741 case DW_CFA_def_cfa_offset_sf : // 0x13 (CFA Definition Instruction) 742 { 743 // takes a signed LEB128 operand representing a factored 744 // offset. This instruction is identical to DW_CFA_def_cfa_offset 745 // except that the operand is signed and factored. 746 op_offset = (int32_t)m_cfi_data.GetSLEB128(&offset) * data_align; 747 row->SetCFAOffset (op_offset); 748 } 749 break; 750 751 case DW_CFA_val_expression : // 0x16 752 { 753 // takes two operands: an unsigned LEB128 value representing a register 754 // number, and a DW_FORM_block value representing a DWARF expression. 755 // The required action is to change the rule for the register indicated 756 // by the register number to be a val_expression(E) rule where E is the 757 // DWARF expression. That is, the DWARF expression computes the value of 758 // the given register. The value of the CFA is pushed on the DWARF 759 // evaluation stack prior to execution of the DWARF expression. 760 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 761 uint32_t block_len = (uint32_t)m_cfi_data.GetULEB128(&offset); 762 const uint8_t* block_data = (uint8_t*)m_cfi_data.GetData(&offset, block_len); 763//#if defined(__i386__) || defined(__x86_64__) 764// // The EH frame info for EIP and RIP contains code that looks for traps to 765// // be a specific type and increments the PC. 766// // For i386: 767// // DW_CFA_val_expression where: 768// // eip = DW_OP_breg6(+28), DW_OP_deref, DW_OP_dup, DW_OP_plus_uconst(0x34), 769// // DW_OP_deref, DW_OP_swap, DW_OP_plus_uconst(0), DW_OP_deref, 770// // DW_OP_dup, DW_OP_lit3, DW_OP_ne, DW_OP_swap, DW_OP_lit4, DW_OP_ne, 771// // DW_OP_and, DW_OP_plus 772// // This basically does a: 773// // eip = ucontenxt.mcontext32->gpr.eip; 774// // if (ucontenxt.mcontext32->exc.trapno != 3 && ucontenxt.mcontext32->exc.trapno != 4) 775// // eip++; 776// // 777// // For x86_64: 778// // DW_CFA_val_expression where: 779// // rip = DW_OP_breg3(+48), DW_OP_deref, DW_OP_dup, DW_OP_plus_uconst(0x90), DW_OP_deref, 780// // DW_OP_swap, DW_OP_plus_uconst(0), DW_OP_deref_size(4), DW_OP_dup, DW_OP_lit3, 781// // DW_OP_ne, DW_OP_swap, DW_OP_lit4, DW_OP_ne, DW_OP_and, DW_OP_plus 782// // This basically does a: 783// // rip = ucontenxt.mcontext64->gpr.rip; 784// // if (ucontenxt.mcontext64->exc.trapno != 3 && ucontenxt.mcontext64->exc.trapno != 4) 785// // rip++; 786// // The trap comparisons and increments are not needed as it hoses up the unwound PC which 787// // is expected to point at least past the instruction that causes the fault/trap. So we 788// // take it out by trimming the expression right at the first "DW_OP_swap" opcodes 789// if (block_data != NULL && thread->GetPCRegNum(Thread::GCC) == reg_num) 790// { 791// if (thread->Is64Bit()) 792// { 793// if (block_len > 9 && block_data[8] == DW_OP_swap && block_data[9] == DW_OP_plus_uconst) 794// block_len = 8; 795// } 796// else 797// { 798// if (block_len > 8 && block_data[7] == DW_OP_swap && block_data[8] == DW_OP_plus_uconst) 799// block_len = 7; 800// } 801// } 802//#endif 803 reg_location.SetIsDWARFExpression(block_data, block_len); 804 row->SetRegisterInfo (reg_num, reg_location); 805 } 806 break; 807 808 case DW_CFA_val_offset : // 0x14 809 case DW_CFA_val_offset_sf : // 0x15 810 default: 811 break; 812 } 813 } 814 } 815 unwind_plan.AppendRow(row); 816 817 return true; 818} 819