DWARFCallFrameInfo.cpp revision c529786f590044117cc96f55137ea7db4e1b92ed
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 27using namespace lldb; 28using namespace lldb_private; 29 30DWARFCallFrameInfo::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 44DWARFCallFrameInfo::~DWARFCallFrameInfo() 45{ 46} 47 48 49bool 50DWARFCallFrameInfo::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 59bool 60DWARFCallFrameInfo::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 68bool 69DWARFCallFrameInfo::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 100const DWARFCallFrameInfo::CIE* 101DWARFCallFrameInfo::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 116DWARFCallFrameInfo::CIESP 117DWARFCallFrameInfo::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 275void 276DWARFCallFrameInfo::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 291void 292DWARFCallFrameInfo::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 351bool 352DWARFCallFrameInfo::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 tmp_uval32; 402 uint32_t code_align = cie->code_align; 403 int32_t data_align = cie->data_align; 404 405 unwind_plan.SetPlanValidAddressRange (range); 406 UnwindPlan::Row row = cie->initial_row; 407 408 unwind_plan.SetRegisterKind (m_reg_kind); 409 410 UnwindPlan::Row::RegisterLocation reg_location; 411 while (m_cfi_data.ValidOffset(offset) && offset < end_offset) 412 { 413 uint8_t inst = m_cfi_data.GetU8(&offset); 414 uint8_t primary_opcode = inst & 0xC0; 415 uint8_t extended_opcode = inst & 0x3F; 416 417 if (primary_opcode) 418 { 419 switch (primary_opcode) 420 { 421 case DW_CFA_advance_loc : // (Row Creation Instruction) 422 { // 0x40 - high 2 bits are 0x1, lower 6 bits are delta 423 // takes a single argument that represents a constant delta. The 424 // required action is to create a new table row with a location 425 // value that is computed by taking the current entry's location 426 // value and adding (delta * code_align). All other 427 // values in the new row are initially identical to the current row. 428 unwind_plan.AppendRow(row); 429 row.SlideOffset(extended_opcode * code_align); 430 } 431 break; 432 433 case DW_CFA_offset : 434 { // 0x80 - high 2 bits are 0x2, lower 6 bits are register 435 // takes two arguments: an unsigned LEB128 constant representing a 436 // factored offset and a register number. The required action is to 437 // change the rule for the register indicated by the register number 438 // to be an offset(N) rule with a value of 439 // (N = factored offset * data_align). 440 reg_num = extended_opcode; 441 op_offset = (int32_t)m_cfi_data.GetULEB128(&offset) * data_align; 442 reg_location.SetAtCFAPlusOffset(op_offset); 443 row.SetRegisterInfo (reg_num, reg_location); 444 } 445 break; 446 447 case DW_CFA_restore : 448 { // 0xC0 - high 2 bits are 0x3, lower 6 bits are register 449 // takes a single argument that represents a register number. The 450 // required action is to change the rule for the indicated register 451 // to the rule assigned it by the initial_instructions in the CIE. 452 reg_num = extended_opcode; 453 // We only keep enough register locations around to 454 // unwind what is in our thread, and these are organized 455 // by the register index in that state, so we need to convert our 456 // GCC register number from the EH frame info, to a register index 457 458 if (unwind_plan.IsValidRowIndex(0) && unwind_plan.GetRowAtIndex(0).GetRegisterInfo(reg_num, reg_location)) 459 row.SetRegisterInfo (reg_num, reg_location); 460 } 461 break; 462 } 463 } 464 else 465 { 466 switch (extended_opcode) 467 { 468 case DW_CFA_nop : // 0x0 469 break; 470 471 case DW_CFA_set_loc : // 0x1 (Row Creation Instruction) 472 { 473 // DW_CFA_set_loc takes a single argument that represents an address. 474 // The required action is to create a new table row using the 475 // specified address as the location. All other values in the new row 476 // are initially identical to the current row. The new location value 477 // should always be greater than the current one. 478 unwind_plan.AppendRow(row); 479 row.SetOffset(m_cfi_data.GetPointer(&offset) - startaddr.GetFileAddress()); 480 } 481 break; 482 483 case DW_CFA_advance_loc1 : // 0x2 (Row Creation Instruction) 484 { 485 // takes a single uword argument that represents a constant delta. 486 // This instruction is identical to DW_CFA_advance_loc except for the 487 // encoding and size of the delta argument. 488 unwind_plan.AppendRow(row); 489 row.SlideOffset (m_cfi_data.GetU8(&offset) * code_align); 490 } 491 break; 492 493 case DW_CFA_advance_loc2 : // 0x3 (Row Creation Instruction) 494 { 495 // takes a single uword argument that represents a constant delta. 496 // This instruction is identical to DW_CFA_advance_loc except for the 497 // encoding and size of the delta argument. 498 unwind_plan.AppendRow(row); 499 row.SlideOffset (m_cfi_data.GetU16(&offset) * code_align); 500 } 501 break; 502 503 case DW_CFA_advance_loc4 : // 0x4 (Row Creation Instruction) 504 { 505 // takes a single uword argument that represents a constant delta. 506 // This instruction is identical to DW_CFA_advance_loc except for the 507 // encoding and size of the delta argument. 508 unwind_plan.AppendRow(row); 509 row.SlideOffset (m_cfi_data.GetU32(&offset) * code_align); 510 } 511 break; 512 513 case DW_CFA_offset_extended : // 0x5 514 { 515 // takes two unsigned LEB128 arguments representing a register number 516 // and a factored offset. This instruction is identical to DW_CFA_offset 517 // except for the encoding and size of the register argument. 518 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 519 op_offset = (int32_t)m_cfi_data.GetULEB128(&offset) * data_align; 520 reg_location.SetAtCFAPlusOffset(op_offset); 521 row.SetRegisterInfo (reg_num, reg_location); 522 } 523 break; 524 525 case DW_CFA_restore_extended : // 0x6 526 { 527 // takes a single unsigned LEB128 argument that represents a register 528 // number. This instruction is identical to DW_CFA_restore except for 529 // the encoding and size of the register argument. 530 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 531 if (unwind_plan.IsValidRowIndex(0) && unwind_plan.GetRowAtIndex(0).GetRegisterInfo(reg_num, reg_location)) 532 row.SetRegisterInfo (reg_num, reg_location); 533 } 534 break; 535 536 case DW_CFA_undefined : // 0x7 537 { 538 // takes a single unsigned LEB128 argument that represents a register 539 // number. The required action is to set the rule for the specified 540 // register to undefined. 541 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 542 reg_location.SetUndefined(); 543 row.SetRegisterInfo (reg_num, reg_location); 544 } 545 break; 546 547 case DW_CFA_same_value : // 0x8 548 { 549 // takes a single unsigned LEB128 argument that represents a register 550 // number. The required action is to set the rule for the specified 551 // register to same value. 552 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 553 reg_location.SetSame(); 554 row.SetRegisterInfo (reg_num, reg_location); 555 } 556 break; 557 558 case DW_CFA_register : // 0x9 559 { 560 // takes two unsigned LEB128 arguments representing register numbers. 561 // The required action is to set the rule for the first register to be 562 // the second register. 563 564 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 565 uint32_t other_reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 566 reg_location.SetInRegister(other_reg_num); 567 row.SetRegisterInfo (reg_num, reg_location); 568 } 569 break; 570 571 case DW_CFA_remember_state : // 0xA 572 // These instructions define a stack of information. Encountering the 573 // DW_CFA_remember_state instruction means to save the rules for every 574 // register on the current row on the stack. Encountering the 575 // DW_CFA_restore_state instruction means to pop the set of rules off 576 // the stack and place them in the current row. (This operation is 577 // useful for compilers that move epilogue code into the body of a 578 // function.) 579 unwind_plan.AppendRow (row); 580 break; 581 582 case DW_CFA_restore_state : // 0xB 583 // These instructions define a stack of information. Encountering the 584 // DW_CFA_remember_state instruction means to save the rules for every 585 // register on the current row on the stack. Encountering the 586 // DW_CFA_restore_state instruction means to pop the set of rules off 587 // the stack and place them in the current row. (This operation is 588 // useful for compilers that move epilogue code into the body of a 589 // function.) 590 { 591 row = unwind_plan.GetRowAtIndex(unwind_plan.GetRowCount() - 1); 592 } 593 break; 594 595 case DW_CFA_def_cfa : // 0xC (CFA Definition Instruction) 596 { 597 // Takes two unsigned LEB128 operands representing a register 598 // number and a (non-factored) offset. The required action 599 // is to define the current CFA rule to use the provided 600 // register and offset. 601 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 602 op_offset = (int32_t)m_cfi_data.GetULEB128(&offset); 603 row.SetCFARegister (reg_num); 604 row.SetCFAOffset (op_offset); 605 } 606 break; 607 608 case DW_CFA_def_cfa_register : // 0xD (CFA Definition Instruction) 609 { 610 // takes a single unsigned LEB128 argument representing a register 611 // number. The required action is to define the current CFA rule to 612 // use the provided register (but to keep the old offset). 613 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 614 row.SetCFARegister (reg_num); 615 } 616 break; 617 618 case DW_CFA_def_cfa_offset : // 0xE (CFA Definition Instruction) 619 { 620 // Takes a single unsigned LEB128 operand representing a 621 // (non-factored) offset. The required action is to define 622 // the current CFA rule to use the provided offset (but 623 // to keep the old register). 624 op_offset = (int32_t)m_cfi_data.GetULEB128(&offset); 625 row.SetCFAOffset (op_offset); 626 } 627 break; 628 629 case DW_CFA_def_cfa_expression : // 0xF (CFA Definition Instruction) 630 { 631 size_t block_len = (size_t)m_cfi_data.GetULEB128(&offset); 632 offset += (uint32_t)block_len; 633 } 634 break; 635 636 case DW_CFA_expression : // 0x10 637 { 638 // Takes two operands: an unsigned LEB128 value representing 639 // a register number, and a DW_FORM_block value representing a DWARF 640 // expression. The required action is to change the rule for the 641 // register indicated by the register number to be an expression(E) 642 // rule where E is the DWARF expression. That is, the DWARF 643 // expression computes the address. The value of the CFA is 644 // pushed on the DWARF evaluation stack prior to execution of 645 // the DWARF expression. 646 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 647 uint32_t block_len = (uint32_t)m_cfi_data.GetULEB128(&offset); 648 const uint8_t *block_data = (uint8_t *)m_cfi_data.GetData(&offset, block_len); 649 650 reg_location.SetAtDWARFExpression(block_data, block_len); 651 row.SetRegisterInfo (reg_num, reg_location); 652 } 653 break; 654 655 case DW_CFA_offset_extended_sf : // 0x11 656 { 657 // takes two operands: an unsigned LEB128 value representing a 658 // register number and a signed LEB128 factored offset. This 659 // instruction is identical to DW_CFA_offset_extended except 660 //that the second operand is signed and factored. 661 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 662 op_offset = (int32_t)m_cfi_data.GetSLEB128(&offset) * data_align; 663 reg_location.SetAtCFAPlusOffset(op_offset); 664 row.SetRegisterInfo (reg_num, reg_location); 665 } 666 break; 667 668 case DW_CFA_def_cfa_sf : // 0x12 (CFA Definition Instruction) 669 { 670 // Takes two operands: an unsigned LEB128 value representing 671 // a register number and a signed LEB128 factored offset. 672 // This instruction is identical to DW_CFA_def_cfa except 673 // that the second operand is signed and factored. 674 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 675 op_offset = (int32_t)m_cfi_data.GetSLEB128(&offset) * data_align; 676 row.SetCFARegister (reg_num); 677 row.SetCFAOffset (op_offset); 678 } 679 break; 680 681 case DW_CFA_def_cfa_offset_sf : // 0x13 (CFA Definition Instruction) 682 { 683 // takes a signed LEB128 operand representing a factored 684 // offset. This instruction is identical to DW_CFA_def_cfa_offset 685 // except that the operand is signed and factored. 686 op_offset = (int32_t)m_cfi_data.GetSLEB128(&offset) * data_align; 687 row.SetCFAOffset (op_offset); 688 } 689 break; 690 691 case DW_CFA_val_expression : // 0x16 692 { 693 // takes two operands: an unsigned LEB128 value representing a register 694 // number, and a DW_FORM_block value representing a DWARF expression. 695 // The required action is to change the rule for the register indicated 696 // by the register number to be a val_expression(E) rule where E is the 697 // DWARF expression. That is, the DWARF expression computes the value of 698 // the given register. The value of the CFA is pushed on the DWARF 699 // evaluation stack prior to execution of the DWARF expression. 700 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 701 uint32_t block_len = (uint32_t)m_cfi_data.GetULEB128(&offset); 702 const uint8_t* block_data = (uint8_t*)m_cfi_data.GetData(&offset, block_len); 703//#if defined(__i386__) || defined(__x86_64__) 704// // The EH frame info for EIP and RIP contains code that looks for traps to 705// // be a specific type and increments the PC. 706// // For i386: 707// // DW_CFA_val_expression where: 708// // eip = DW_OP_breg6(+28), DW_OP_deref, DW_OP_dup, DW_OP_plus_uconst(0x34), 709// // DW_OP_deref, DW_OP_swap, DW_OP_plus_uconst(0), DW_OP_deref, 710// // DW_OP_dup, DW_OP_lit3, DW_OP_ne, DW_OP_swap, DW_OP_lit4, DW_OP_ne, 711// // DW_OP_and, DW_OP_plus 712// // This basically does a: 713// // eip = ucontenxt.mcontext32->gpr.eip; 714// // if (ucontenxt.mcontext32->exc.trapno != 3 && ucontenxt.mcontext32->exc.trapno != 4) 715// // eip++; 716// // 717// // For x86_64: 718// // DW_CFA_val_expression where: 719// // rip = DW_OP_breg3(+48), DW_OP_deref, DW_OP_dup, DW_OP_plus_uconst(0x90), DW_OP_deref, 720// // DW_OP_swap, DW_OP_plus_uconst(0), DW_OP_deref_size(4), DW_OP_dup, DW_OP_lit3, 721// // DW_OP_ne, DW_OP_swap, DW_OP_lit4, DW_OP_ne, DW_OP_and, DW_OP_plus 722// // This basically does a: 723// // rip = ucontenxt.mcontext64->gpr.rip; 724// // if (ucontenxt.mcontext64->exc.trapno != 3 && ucontenxt.mcontext64->exc.trapno != 4) 725// // rip++; 726// // The trap comparisons and increments are not needed as it hoses up the unwound PC which 727// // is expected to point at least past the instruction that causes the fault/trap. So we 728// // take it out by trimming the expression right at the first "DW_OP_swap" opcodes 729// if (block_data != NULL && thread->GetPCRegNum(Thread::GCC) == reg_num) 730// { 731// if (thread->Is64Bit()) 732// { 733// if (block_len > 9 && block_data[8] == DW_OP_swap && block_data[9] == DW_OP_plus_uconst) 734// block_len = 8; 735// } 736// else 737// { 738// if (block_len > 8 && block_data[7] == DW_OP_swap && block_data[8] == DW_OP_plus_uconst) 739// block_len = 7; 740// } 741// } 742//#endif 743 reg_location.SetIsDWARFExpression(block_data, block_len); 744 row.SetRegisterInfo (reg_num, reg_location); 745 } 746 break; 747 748 case DW_CFA_val_offset : // 0x14 749 case DW_CFA_val_offset_sf : // 0x15 750 default: 751 tmp_uval32 = extended_opcode; 752 break; 753 } 754 } 755 } 756 unwind_plan.AppendRow(row); 757 758 return true; 759} 760