DWARFCallFrameInfo.cpp revision 4e12194c2d784868e5d2236f9546de104531bdc0
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/Symbol/DWARFCallFrameInfo.h" 18#include "lldb/Core/ArchSpec.h" 19#include "lldb/Core/Module.h" 20#include "lldb/Symbol/ObjectFile.h" 21#include "lldb/Target/RegisterContext.h" 22#include "lldb/Core/Section.h" 23#include "lldb/Target/Thread.h" 24#include "lldb/Symbol/UnwindPlan.h" 25 26using namespace lldb; 27using namespace lldb_private; 28 29DWARFCallFrameInfo::DWARFCallFrameInfo(ObjectFile& objfile, SectionSP& section, uint32_t reg_kind, bool is_eh_frame) : 30 m_objfile (objfile), 31 m_section (section), 32 m_reg_kind (reg_kind), // The flavor of registers that the CFI data uses (enum RegisterKind) 33 m_cie_map (), 34 m_cfi_data (), 35 m_cfi_data_initialized (false), 36 m_fde_index (), 37 m_fde_index_initialized (false), 38 m_is_eh_frame (is_eh_frame) 39{ 40} 41 42DWARFCallFrameInfo::~DWARFCallFrameInfo() 43{ 44} 45 46 47bool 48DWARFCallFrameInfo::GetAddressRange (Address addr, AddressRange &range) 49{ 50 FDEEntry fde_entry; 51 if (GetFDEEntryByAddress (addr, fde_entry) == false) 52 return false; 53 range = fde_entry.bounds; 54 return true; 55} 56 57bool 58DWARFCallFrameInfo::GetUnwindPlan (Address addr, UnwindPlan& unwind_plan) 59{ 60 FDEEntry fde_entry; 61 if (GetFDEEntryByAddress (addr, fde_entry) == false) 62 return false; 63 return FDEToUnwindPlan (fde_entry.offset, addr, unwind_plan); 64} 65 66bool 67DWARFCallFrameInfo::GetFDEEntryByAddress (Address addr, FDEEntry& fde_entry) 68{ 69 if (m_section.get() == NULL) 70 return false; 71 GetFDEIndex(); 72 73 struct FDEEntry searchfde; 74 searchfde.bounds = AddressRange (addr, 1); 75 76 std::vector<FDEEntry>::const_iterator idx; 77 if (m_fde_index.size() == 0) 78 return false; 79 80 idx = std::lower_bound (m_fde_index.begin(), m_fde_index.end(), searchfde); 81 if (idx == m_fde_index.end()) 82 { 83 --idx; 84 } 85 if (idx != m_fde_index.begin() && idx->bounds.GetBaseAddress().GetOffset() != addr.GetOffset()) 86 { 87 --idx; 88 } 89 if (idx->bounds.ContainsFileAddress (addr)) 90 { 91 fde_entry = *idx; 92 return true; 93 } 94 95 return false; 96} 97 98const DWARFCallFrameInfo::CIE* 99DWARFCallFrameInfo::GetCIE(dw_offset_t cie_offset) 100{ 101 cie_map_t::iterator pos = m_cie_map.find(cie_offset); 102 103 if (pos != m_cie_map.end()) 104 { 105 // Parse and cache the CIE 106 if (pos->second.get() == NULL) 107 pos->second = ParseCIE (cie_offset); 108 109 return pos->second.get(); 110 } 111 return NULL; 112} 113 114DWARFCallFrameInfo::CIESP 115DWARFCallFrameInfo::ParseCIE (const dw_offset_t cie_offset) 116{ 117 CIESP cie_sp(new CIE(cie_offset)); 118 dw_offset_t offset = cie_offset; 119 if (m_cfi_data_initialized == false) 120 { 121 m_section->ReadSectionDataFromObjectFile (&m_objfile, m_cfi_data); 122 m_cfi_data_initialized = true; 123 } 124 const uint32_t length = m_cfi_data.GetU32(&offset); 125 const dw_offset_t cie_id = m_cfi_data.GetU32(&offset); 126 const dw_offset_t end_offset = cie_offset + length + 4; 127 if (length > 0 && (!m_is_eh_frame && cie_id == 0xfffffffful) || (m_is_eh_frame && cie_id == 0ul)) 128 { 129 size_t i; 130 // cie.offset = cie_offset; 131 // cie.length = length; 132 // cie.cieID = cieID; 133 cie_sp->ptr_encoding = DW_EH_PE_absptr; 134 cie_sp->version = m_cfi_data.GetU8(&offset); 135 136 for (i=0; i<CFI_AUG_MAX_SIZE; ++i) 137 { 138 cie_sp->augmentation[i] = m_cfi_data.GetU8(&offset); 139 if (cie_sp->augmentation[i] == '\0') 140 { 141 // Zero out remaining bytes in augmentation string 142 for (size_t j = i+1; j<CFI_AUG_MAX_SIZE; ++j) 143 cie_sp->augmentation[j] = '\0'; 144 145 break; 146 } 147 } 148 149 if (i == CFI_AUG_MAX_SIZE && cie_sp->augmentation[CFI_AUG_MAX_SIZE-1] != '\0') 150 { 151 fprintf(stderr, "CIE parse error: CIE augmentation string was too large for the fixed sized buffer of %d bytes.\n", CFI_AUG_MAX_SIZE); 152 return cie_sp; 153 } 154 cie_sp->code_align = (uint32_t)m_cfi_data.GetULEB128(&offset); 155 cie_sp->data_align = (int32_t)m_cfi_data.GetSLEB128(&offset); 156 cie_sp->return_addr_reg_num = m_cfi_data.GetU8(&offset); 157 158 if (cie_sp->augmentation[0]) 159 { 160 // Get the length of the eh_frame augmentation data 161 // which starts with a ULEB128 length in bytes 162 const size_t aug_data_len = (size_t)m_cfi_data.GetULEB128(&offset); 163 const size_t aug_data_end = offset + aug_data_len; 164 const size_t aug_str_len = strlen(cie_sp->augmentation); 165 // A 'z' may be present as the first character of the string. 166 // If present, the Augmentation Data field shall be present. 167 // The contents of the Augmentation Data shall be intepreted 168 // according to other characters in the Augmentation String. 169 if (cie_sp->augmentation[0] == 'z') 170 { 171 // Extract the Augmentation Data 172 size_t aug_str_idx = 0; 173 for (aug_str_idx = 1; aug_str_idx < aug_str_len; aug_str_idx++) 174 { 175 char aug = cie_sp->augmentation[aug_str_idx]; 176 switch (aug) 177 { 178 case 'L': 179 // Indicates the presence of one argument in the 180 // Augmentation Data of the CIE, and a corresponding 181 // argument in the Augmentation Data of the FDE. The 182 // argument in the Augmentation Data of the CIE is 183 // 1-byte and represents the pointer encoding used 184 // for the argument in the Augmentation Data of the 185 // FDE, which is the address of a language-specific 186 // data area (LSDA). The size of the LSDA pointer is 187 // specified by the pointer encoding used. 188 m_cfi_data.GetU8(&offset); 189 break; 190 191 case 'P': 192 // Indicates the presence of two arguments in the 193 // Augmentation Data of the cie_sp-> The first argument 194 // is 1-byte and represents the pointer encoding 195 // used for the second argument, which is the 196 // address of a personality routine handler. The 197 // size of the personality routine pointer is 198 // specified by the pointer encoding used. 199 { 200 uint8_t arg_ptr_encoding = m_cfi_data.GetU8(&offset); 201 m_cfi_data.GetGNUEHPointer(&offset, arg_ptr_encoding, LLDB_INVALID_ADDRESS, LLDB_INVALID_ADDRESS, LLDB_INVALID_ADDRESS); 202 } 203 break; 204 205 case 'R': 206 // A 'R' may be present at any position after the 207 // first character of the string. The Augmentation 208 // Data shall include a 1 byte argument that 209 // represents the pointer encoding for the address 210 // pointers used in the FDE. 211 cie_sp->ptr_encoding = m_cfi_data.GetU8(&offset); 212 break; 213 } 214 } 215 } 216 else if (strcmp(cie_sp->augmentation, "eh") == 0) 217 { 218 // If the Augmentation string has the value "eh", then 219 // the EH Data field shall be present 220 } 221 222 // Set the offset to be the end of the augmentation data just in case 223 // we didn't understand any of the data. 224 offset = (uint32_t)aug_data_end; 225 } 226 227 if (end_offset > offset) 228 { 229 cie_sp->inst_offset = offset; 230 cie_sp->inst_length = end_offset - offset; 231 } 232 while (offset < end_offset) 233 { 234 uint8_t inst = m_cfi_data.GetU8(&offset); 235 uint8_t primary_opcode = inst & 0xC0; 236 uint8_t extended_opcode = inst & 0x3F; 237 238 if (extended_opcode == DW_CFA_def_cfa) 239 { 240 // Takes two unsigned LEB128 operands representing a register 241 // number and a (non-factored) offset. The required action 242 // is to define the current CFA rule to use the provided 243 // register and offset. 244 uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 245 int op_offset = (int32_t)m_cfi_data.GetULEB128(&offset); 246 cie_sp->initial_row.SetCFARegister (reg_num); 247 cie_sp->initial_row.SetCFAOffset (op_offset); 248 continue; 249 } 250 if (primary_opcode == DW_CFA_offset) 251 { 252 // 0x80 - high 2 bits are 0x2, lower 6 bits are register. 253 // Takes two arguments: an unsigned LEB128 constant representing a 254 // factored offset and a register number. The required action is to 255 // change the rule for the register indicated by the register number 256 // to be an offset(N) rule with a value of 257 // (N = factored offset * data_align). 258 uint32_t reg_num = extended_opcode; 259 int op_offset = (int32_t)m_cfi_data.GetULEB128(&offset) * cie_sp->data_align; 260 UnwindPlan::Row::RegisterLocation reg_location; 261 reg_location.SetAtCFAPlusOffset(op_offset); 262 cie_sp->initial_row.SetRegisterInfo (reg_num, reg_location); 263 continue; 264 } 265 if (extended_opcode == DW_CFA_nop) 266 { 267 continue; 268 } 269 break; // Stop if we hit an unrecognized opcode 270 } 271 } 272 273 return cie_sp; 274} 275 276// Scan through the eh_frame or debug_frame section looking for FDEs and noting the start/end addresses 277// of the functions and a pointer back to the function's FDE for later expansion. 278// Internalize CIEs as we come across them. 279 280void 281DWARFCallFrameInfo::GetFDEIndex () 282{ 283 if (m_section.get() == NULL) 284 return; 285 if (m_fde_index_initialized) 286 return; 287 288 289 dw_offset_t offset = 0; 290 if (m_cfi_data_initialized == false) 291 { 292 Log *log = GetLogIfAllCategoriesSet (LIBLLDB_LOG_UNWIND); 293 if (log) 294 { 295 log->Printf ("Reading eh_frame information for %s", m_objfile.GetFileSpec().GetFilename().GetCString()); 296 } 297 m_section->ReadSectionDataFromObjectFile (&m_objfile, m_cfi_data); 298 m_cfi_data_initialized = true; 299 } 300 while (m_cfi_data.ValidOffsetForDataOfSize (offset, 8)) 301 { 302 dw_offset_t current_entry = offset; 303 uint32_t len = m_cfi_data.GetU32 (&offset); 304 dw_offset_t next_entry = current_entry + len + 4; 305 dw_offset_t cie_id = m_cfi_data.GetU32 (&offset); 306 307 if (cie_id == 0 || cie_id == UINT32_MAX) 308 { 309 m_cie_map[current_entry] = ParseCIE (current_entry); 310 offset = next_entry; 311 continue; 312 } 313 314 const CIE *cie = GetCIE (current_entry + 4 - cie_id); 315 assert (cie != NULL); 316 317 const lldb::addr_t pc_rel_addr = m_section->GetFileAddress(); 318 const lldb::addr_t text_addr = LLDB_INVALID_ADDRESS; 319 const lldb::addr_t data_addr = LLDB_INVALID_ADDRESS; 320 321 lldb::addr_t addr = m_cfi_data.GetGNUEHPointer(&offset, cie->ptr_encoding, pc_rel_addr, text_addr, data_addr); 322 lldb::addr_t length = m_cfi_data.GetGNUEHPointer(&offset, cie->ptr_encoding & DW_EH_PE_MASK_ENCODING, pc_rel_addr, text_addr, data_addr); 323 FDEEntry fde; 324 fde.bounds = AddressRange (addr, length, m_objfile.GetSectionList()); 325 fde.offset = current_entry; 326 m_fde_index.push_back(fde); 327 328 offset = next_entry; 329 } 330 std::sort (m_fde_index.begin(), m_fde_index.end()); 331 m_fde_index_initialized = true; 332} 333 334bool 335DWARFCallFrameInfo::FDEToUnwindPlan (dw_offset_t offset, Address startaddr, UnwindPlan& unwind_plan) 336{ 337 dw_offset_t current_entry = offset; 338 339 if (m_section.get() == NULL) 340 return false; 341 342 if (m_cfi_data_initialized == false) 343 { 344 m_section->ReadSectionDataFromObjectFile (&m_objfile, m_cfi_data); 345 m_cfi_data_initialized = true; 346 } 347 348 uint32_t length = m_cfi_data.GetU32 (&offset); 349 dw_offset_t cie_offset = m_cfi_data.GetU32 (&offset); 350 351 assert (cie_offset != 0 && cie_offset != UINT32_MAX); 352 353 // Translate the CIE_id from the eh_frame format, which 354 // is relative to the FDE offset, into a __eh_frame section 355 // offset 356 if (m_is_eh_frame) 357 { 358 unwind_plan.SetSourceName ("eh_frame CFI"); 359 cie_offset = current_entry + 4 - cie_offset; 360 } 361 else 362 { 363 unwind_plan.SetSourceName ("DWARF CFI"); 364 } 365 366 const CIE *cie = GetCIE (cie_offset); 367 assert (cie != NULL); 368 369 const dw_offset_t end_offset = current_entry + length + 4; 370 371 const lldb::addr_t pc_rel_addr = m_section->GetFileAddress(); 372 const lldb::addr_t text_addr = LLDB_INVALID_ADDRESS; 373 const lldb::addr_t data_addr = LLDB_INVALID_ADDRESS; 374 lldb::addr_t range_base = m_cfi_data.GetGNUEHPointer(&offset, cie->ptr_encoding, pc_rel_addr, text_addr, data_addr); 375 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); 376 AddressRange range (range_base, m_objfile.GetAddressByteSize(), m_objfile.GetSectionList()); 377 range.SetByteSize (range_len); 378 379 if (cie->augmentation[0] == 'z') 380 { 381 uint32_t aug_data_len = (uint32_t)m_cfi_data.GetULEB128(&offset); 382 offset += aug_data_len; 383 } 384 385 uint32_t reg_num = 0; 386 int32_t op_offset = 0; 387 uint32_t tmp_uval32; 388 uint32_t code_align = cie->code_align; 389 int32_t data_align = cie->data_align; 390 391 unwind_plan.SetPlanValidAddressRange (range); 392 UnwindPlan::Row row = cie->initial_row; 393 394 unwind_plan.SetRegisterKind (m_reg_kind); 395 396 UnwindPlan::Row::RegisterLocation reg_location; 397 while (m_cfi_data.ValidOffset(offset) && offset < end_offset) 398 { 399 uint8_t inst = m_cfi_data.GetU8(&offset); 400 uint8_t primary_opcode = inst & 0xC0; 401 uint8_t extended_opcode = inst & 0x3F; 402 403 if (primary_opcode) 404 { 405 switch (primary_opcode) 406 { 407 case DW_CFA_advance_loc : // (Row Creation Instruction) 408 { // 0x40 - high 2 bits are 0x1, lower 6 bits are delta 409 // takes a single argument that represents a constant delta. The 410 // required action is to create a new table row with a location 411 // value that is computed by taking the current entry's location 412 // value and adding (delta * code_align). All other 413 // values in the new row are initially identical to the current row. 414 unwind_plan.AppendRow(row); 415 row.SlideOffset(extended_opcode * code_align); 416 } 417 break; 418 419 case DW_CFA_offset : 420 { // 0x80 - high 2 bits are 0x2, lower 6 bits are register 421 // takes two arguments: an unsigned LEB128 constant representing a 422 // factored offset and a register number. The required action is to 423 // change the rule for the register indicated by the register number 424 // to be an offset(N) rule with a value of 425 // (N = factored offset * data_align). 426 reg_num = extended_opcode; 427 op_offset = (int32_t)m_cfi_data.GetULEB128(&offset) * data_align; 428 reg_location.SetAtCFAPlusOffset(op_offset); 429 row.SetRegisterInfo (reg_num, reg_location); 430 } 431 break; 432 433 case DW_CFA_restore : 434 { // 0xC0 - high 2 bits are 0x3, lower 6 bits are register 435 // takes a single argument that represents a register number. The 436 // required action is to change the rule for the indicated register 437 // to the rule assigned it by the initial_instructions in the CIE. 438 reg_num = extended_opcode; 439 // We only keep enough register locations around to 440 // unwind what is in our thread, and these are organized 441 // by the register index in that state, so we need to convert our 442 // GCC register number from the EH frame info, to a register index 443 444 if (unwind_plan.IsValidRowIndex(0) && unwind_plan.GetRowAtIndex(0).GetRegisterInfo(reg_num, reg_location)) 445 row.SetRegisterInfo (reg_num, reg_location); 446 } 447 break; 448 } 449 } 450 else 451 { 452 switch (extended_opcode) 453 { 454 case DW_CFA_nop : // 0x0 455 break; 456 457 case DW_CFA_set_loc : // 0x1 (Row Creation Instruction) 458 { 459 // DW_CFA_set_loc takes a single argument that represents an address. 460 // The required action is to create a new table row using the 461 // specified address as the location. All other values in the new row 462 // are initially identical to the current row. The new location value 463 // should always be greater than the current one. 464 unwind_plan.AppendRow(row); 465 row.SetOffset(m_cfi_data.GetPointer(&offset) - startaddr.GetFileAddress()); 466 } 467 break; 468 469 case DW_CFA_advance_loc1 : // 0x2 (Row Creation Instruction) 470 { 471 // takes a single uword argument that represents a constant delta. 472 // This instruction is identical to DW_CFA_advance_loc except for the 473 // encoding and size of the delta argument. 474 unwind_plan.AppendRow(row); 475 row.SlideOffset (m_cfi_data.GetU8(&offset) * code_align); 476 } 477 break; 478 479 case DW_CFA_advance_loc2 : // 0x3 (Row Creation Instruction) 480 { 481 // takes a single uword argument that represents a constant delta. 482 // This instruction is identical to DW_CFA_advance_loc except for the 483 // encoding and size of the delta argument. 484 unwind_plan.AppendRow(row); 485 row.SlideOffset (m_cfi_data.GetU16(&offset) * code_align); 486 } 487 break; 488 489 case DW_CFA_advance_loc4 : // 0x4 (Row Creation Instruction) 490 { 491 // takes a single uword argument that represents a constant delta. 492 // This instruction is identical to DW_CFA_advance_loc except for the 493 // encoding and size of the delta argument. 494 unwind_plan.AppendRow(row); 495 row.SlideOffset (m_cfi_data.GetU32(&offset) * code_align); 496 } 497 break; 498 499 case DW_CFA_offset_extended : // 0x5 500 { 501 // takes two unsigned LEB128 arguments representing a register number 502 // and a factored offset. This instruction is identical to DW_CFA_offset 503 // except for the encoding and size of the register argument. 504 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 505 op_offset = (int32_t)m_cfi_data.GetULEB128(&offset) * data_align; 506 reg_location.SetAtCFAPlusOffset(op_offset); 507 row.SetRegisterInfo (reg_num, reg_location); 508 } 509 break; 510 511 case DW_CFA_restore_extended : // 0x6 512 { 513 // takes a single unsigned LEB128 argument that represents a register 514 // number. This instruction is identical to DW_CFA_restore except for 515 // the encoding and size of the register argument. 516 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 517 if (unwind_plan.IsValidRowIndex(0) && unwind_plan.GetRowAtIndex(0).GetRegisterInfo(reg_num, reg_location)) 518 row.SetRegisterInfo (reg_num, reg_location); 519 } 520 break; 521 522 case DW_CFA_undefined : // 0x7 523 { 524 // takes a single unsigned LEB128 argument that represents a register 525 // number. The required action is to set the rule for the specified 526 // register to undefined. 527 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 528 reg_location.SetUndefined(); 529 row.SetRegisterInfo (reg_num, reg_location); 530 } 531 break; 532 533 case DW_CFA_same_value : // 0x8 534 { 535 // takes a single unsigned LEB128 argument that represents a register 536 // number. The required action is to set the rule for the specified 537 // register to same value. 538 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 539 reg_location.SetSame(); 540 row.SetRegisterInfo (reg_num, reg_location); 541 } 542 break; 543 544 case DW_CFA_register : // 0x9 545 { 546 // takes two unsigned LEB128 arguments representing register numbers. 547 // The required action is to set the rule for the first register to be 548 // the second register. 549 550 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 551 uint32_t other_reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 552 reg_location.SetInRegister(other_reg_num); 553 row.SetRegisterInfo (reg_num, reg_location); 554 } 555 break; 556 557 case DW_CFA_remember_state : // 0xA 558 // These instructions define a stack of information. Encountering the 559 // DW_CFA_remember_state instruction means to save the rules for every 560 // register on the current row on the stack. Encountering the 561 // DW_CFA_restore_state instruction means to pop the set of rules off 562 // the stack and place them in the current row. (This operation is 563 // useful for compilers that move epilogue code into the body of a 564 // function.) 565 unwind_plan.AppendRow (row); 566 break; 567 568 case DW_CFA_restore_state : // 0xB 569 // These instructions define a stack of information. Encountering the 570 // DW_CFA_remember_state instruction means to save the rules for every 571 // register on the current row on the stack. Encountering the 572 // DW_CFA_restore_state instruction means to pop the set of rules off 573 // the stack and place them in the current row. (This operation is 574 // useful for compilers that move epilogue code into the body of a 575 // function.) 576 { 577 row = unwind_plan.GetRowAtIndex(unwind_plan.GetRowCount() - 1); 578 } 579 break; 580 581 case DW_CFA_def_cfa : // 0xC (CFA Definition Instruction) 582 { 583 // Takes two unsigned LEB128 operands representing a register 584 // number and a (non-factored) offset. The required action 585 // is to define the current CFA rule to use the provided 586 // register and offset. 587 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 588 op_offset = (int32_t)m_cfi_data.GetULEB128(&offset); 589 row.SetCFARegister (reg_num); 590 row.SetCFAOffset (op_offset); 591 } 592 break; 593 594 case DW_CFA_def_cfa_register : // 0xD (CFA Definition Instruction) 595 { 596 // takes a single unsigned LEB128 argument representing a register 597 // number. The required action is to define the current CFA rule to 598 // use the provided register (but to keep the old offset). 599 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 600 row.SetCFARegister (reg_num); 601 } 602 break; 603 604 case DW_CFA_def_cfa_offset : // 0xE (CFA Definition Instruction) 605 { 606 // Takes a single unsigned LEB128 operand representing a 607 // (non-factored) offset. The required action is to define 608 // the current CFA rule to use the provided offset (but 609 // to keep the old register). 610 op_offset = (int32_t)m_cfi_data.GetULEB128(&offset); 611 row.SetCFAOffset (op_offset); 612 } 613 break; 614 615 case DW_CFA_def_cfa_expression : // 0xF (CFA Definition Instruction) 616 { 617 size_t block_len = (size_t)m_cfi_data.GetULEB128(&offset); 618 offset += (uint32_t)block_len; 619 } 620 break; 621 622 case DW_CFA_expression : // 0x10 623 { 624 // Takes two operands: an unsigned LEB128 value representing 625 // a register number, and a DW_FORM_block value representing a DWARF 626 // expression. The required action is to change the rule for the 627 // register indicated by the register number to be an expression(E) 628 // rule where E is the DWARF expression. That is, the DWARF 629 // expression computes the address. The value of the CFA is 630 // pushed on the DWARF evaluation stack prior to execution of 631 // the DWARF expression. 632 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 633 uint32_t block_len = (uint32_t)m_cfi_data.GetULEB128(&offset); 634 const uint8_t *block_data = (uint8_t *)m_cfi_data.GetData(&offset, block_len); 635 636 reg_location.SetAtDWARFExpression(block_data, block_len); 637 row.SetRegisterInfo (reg_num, reg_location); 638 } 639 break; 640 641 case DW_CFA_offset_extended_sf : // 0x11 642 { 643 // takes two operands: an unsigned LEB128 value representing a 644 // register number and a signed LEB128 factored offset. This 645 // instruction is identical to DW_CFA_offset_extended except 646 //that the second operand is signed and factored. 647 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 648 op_offset = (int32_t)m_cfi_data.GetSLEB128(&offset) * data_align; 649 reg_location.SetAtCFAPlusOffset(op_offset); 650 row.SetRegisterInfo (reg_num, reg_location); 651 } 652 break; 653 654 case DW_CFA_def_cfa_sf : // 0x12 (CFA Definition Instruction) 655 { 656 // Takes two operands: an unsigned LEB128 value representing 657 // a register number and a signed LEB128 factored offset. 658 // This instruction is identical to DW_CFA_def_cfa except 659 // that the second operand is signed and factored. 660 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 661 op_offset = (int32_t)m_cfi_data.GetSLEB128(&offset) * data_align; 662 row.SetCFARegister (reg_num); 663 row.SetCFAOffset (op_offset); 664 } 665 break; 666 667 case DW_CFA_def_cfa_offset_sf : // 0x13 (CFA Definition Instruction) 668 { 669 // takes a signed LEB128 operand representing a factored 670 // offset. This instruction is identical to DW_CFA_def_cfa_offset 671 // except that the operand is signed and factored. 672 op_offset = (int32_t)m_cfi_data.GetSLEB128(&offset) * data_align; 673 row.SetCFAOffset (op_offset); 674 } 675 break; 676 677 case DW_CFA_val_expression : // 0x16 678 { 679 // takes two operands: an unsigned LEB128 value representing a register 680 // number, and a DW_FORM_block value representing a DWARF expression. 681 // The required action is to change the rule for the register indicated 682 // by the register number to be a val_expression(E) rule where E is the 683 // DWARF expression. That is, the DWARF expression computes the value of 684 // the given register. The value of the CFA is pushed on the DWARF 685 // evaluation stack prior to execution of the DWARF expression. 686 reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset); 687 uint32_t block_len = (uint32_t)m_cfi_data.GetULEB128(&offset); 688 const uint8_t* block_data = (uint8_t*)m_cfi_data.GetData(&offset, block_len); 689//#if defined(__i386__) || defined(__x86_64__) 690// // The EH frame info for EIP and RIP contains code that looks for traps to 691// // be a specific type and increments the PC. 692// // For i386: 693// // DW_CFA_val_expression where: 694// // eip = DW_OP_breg6(+28), DW_OP_deref, DW_OP_dup, DW_OP_plus_uconst(0x34), 695// // DW_OP_deref, DW_OP_swap, DW_OP_plus_uconst(0), DW_OP_deref, 696// // DW_OP_dup, DW_OP_lit3, DW_OP_ne, DW_OP_swap, DW_OP_lit4, DW_OP_ne, 697// // DW_OP_and, DW_OP_plus 698// // This basically does a: 699// // eip = ucontenxt.mcontext32->gpr.eip; 700// // if (ucontenxt.mcontext32->exc.trapno != 3 && ucontenxt.mcontext32->exc.trapno != 4) 701// // eip++; 702// // 703// // For x86_64: 704// // DW_CFA_val_expression where: 705// // rip = DW_OP_breg3(+48), DW_OP_deref, DW_OP_dup, DW_OP_plus_uconst(0x90), DW_OP_deref, 706// // DW_OP_swap, DW_OP_plus_uconst(0), DW_OP_deref_size(4), DW_OP_dup, DW_OP_lit3, 707// // DW_OP_ne, DW_OP_swap, DW_OP_lit4, DW_OP_ne, DW_OP_and, DW_OP_plus 708// // This basically does a: 709// // rip = ucontenxt.mcontext64->gpr.rip; 710// // if (ucontenxt.mcontext64->exc.trapno != 3 && ucontenxt.mcontext64->exc.trapno != 4) 711// // rip++; 712// // The trap comparisons and increments are not needed as it hoses up the unwound PC which 713// // is expected to point at least past the instruction that causes the fault/trap. So we 714// // take it out by trimming the expression right at the first "DW_OP_swap" opcodes 715// if (block_data != NULL && thread->GetPCRegNum(Thread::GCC) == reg_num) 716// { 717// if (thread->Is64Bit()) 718// { 719// if (block_len > 9 && block_data[8] == DW_OP_swap && block_data[9] == DW_OP_plus_uconst) 720// block_len = 8; 721// } 722// else 723// { 724// if (block_len > 8 && block_data[7] == DW_OP_swap && block_data[8] == DW_OP_plus_uconst) 725// block_len = 7; 726// } 727// } 728//#endif 729 reg_location.SetIsDWARFExpression(block_data, block_len); 730 row.SetRegisterInfo (reg_num, reg_location); 731 } 732 break; 733 734 case DW_CFA_val_offset : // 0x14 735 case DW_CFA_val_offset_sf : // 0x15 736 default: 737 tmp_uval32 = extended_opcode; 738 break; 739 } 740 } 741 } 742 unwind_plan.AppendRow(row); 743 744 return true; 745} 746