1 //===-- DWARFExpression.cpp -----------------------------------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 #include "lldb/Expression/DWARFExpression.h" 10 11 #include <inttypes.h> 12 13 #include <vector> 14 15 #include "lldb/Core/Module.h" 16 #include "lldb/Core/Value.h" 17 #include "lldb/Core/dwarf.h" 18 #include "lldb/Utility/DataEncoder.h" 19 #include "lldb/Utility/Log.h" 20 #include "lldb/Utility/RegisterValue.h" 21 #include "lldb/Utility/Scalar.h" 22 #include "lldb/Utility/StreamString.h" 23 #include "lldb/Utility/VMRange.h" 24 25 #include "lldb/Host/Host.h" 26 #include "lldb/Utility/Endian.h" 27 28 #include "lldb/Symbol/Function.h" 29 30 #include "lldb/Target/ABI.h" 31 #include "lldb/Target/ExecutionContext.h" 32 #include "lldb/Target/Process.h" 33 #include "lldb/Target/RegisterContext.h" 34 #include "lldb/Target/StackFrame.h" 35 #include "lldb/Target/StackID.h" 36 #include "lldb/Target/Target.h" 37 #include "lldb/Target/Thread.h" 38 39 #include "Plugins/SymbolFile/DWARF/DWARFUnit.h" 40 41 using namespace lldb; 42 using namespace lldb_private; 43 44 static lldb::addr_t 45 ReadAddressFromDebugAddrSection(const DWARFUnit *dwarf_cu, 46 uint32_t index) { 47 uint32_t index_size = dwarf_cu->GetAddressByteSize(); 48 dw_offset_t addr_base = dwarf_cu->GetAddrBase(); 49 lldb::offset_t offset = addr_base + index * index_size; 50 const DWARFDataExtractor &data = 51 dwarf_cu->GetSymbolFileDWARF().GetDWARFContext().getOrLoadAddrData(); 52 if (data.ValidOffsetForDataOfSize(offset, index_size)) 53 return data.GetMaxU64_unchecked(&offset, index_size); 54 return LLDB_INVALID_ADDRESS; 55 } 56 57 // DWARFExpression constructor 58 DWARFExpression::DWARFExpression() 59 : m_module_wp(), m_data(), m_dwarf_cu(nullptr), 60 m_reg_kind(eRegisterKindDWARF) {} 61 62 DWARFExpression::DWARFExpression(lldb::ModuleSP module_sp, 63 const DataExtractor &data, 64 const DWARFUnit *dwarf_cu) 65 : m_module_wp(), m_data(data), m_dwarf_cu(dwarf_cu), 66 m_reg_kind(eRegisterKindDWARF) { 67 if (module_sp) 68 m_module_wp = module_sp; 69 } 70 71 // Destructor 72 DWARFExpression::~DWARFExpression() {} 73 74 bool DWARFExpression::IsValid() const { return m_data.GetByteSize() > 0; } 75 76 void DWARFExpression::UpdateValue(uint64_t const_value, 77 lldb::offset_t const_value_byte_size, 78 uint8_t addr_byte_size) { 79 if (!const_value_byte_size) 80 return; 81 82 m_data.SetData( 83 DataBufferSP(new DataBufferHeap(&const_value, const_value_byte_size))); 84 m_data.SetByteOrder(endian::InlHostByteOrder()); 85 m_data.SetAddressByteSize(addr_byte_size); 86 } 87 88 void DWARFExpression::DumpLocation(Stream *s, const DataExtractor &data, 89 lldb::DescriptionLevel level, 90 ABI *abi) const { 91 llvm::DWARFExpression(data.GetAsLLVM(), data.GetAddressByteSize()) 92 .print(s->AsRawOstream(), abi ? &abi->GetMCRegisterInfo() : nullptr, 93 nullptr); 94 } 95 96 void DWARFExpression::SetLocationListAddresses(addr_t cu_file_addr, 97 addr_t func_file_addr) { 98 m_loclist_addresses = LoclistAddresses{cu_file_addr, func_file_addr}; 99 } 100 101 int DWARFExpression::GetRegisterKind() { return m_reg_kind; } 102 103 void DWARFExpression::SetRegisterKind(RegisterKind reg_kind) { 104 m_reg_kind = reg_kind; 105 } 106 107 bool DWARFExpression::IsLocationList() const { 108 return bool(m_loclist_addresses); 109 } 110 111 namespace { 112 /// Implement enough of the DWARFObject interface in order to be able to call 113 /// DWARFLocationTable::dumpLocationList. We don't have access to a real 114 /// DWARFObject here because DWARFExpression is used in non-DWARF scenarios too. 115 class DummyDWARFObject final: public llvm::DWARFObject { 116 public: 117 DummyDWARFObject(bool IsLittleEndian) : IsLittleEndian(IsLittleEndian) {} 118 119 bool isLittleEndian() const override { return IsLittleEndian; } 120 121 llvm::Optional<llvm::RelocAddrEntry> find(const llvm::DWARFSection &Sec, 122 uint64_t Pos) const override { 123 return llvm::None; 124 } 125 private: 126 bool IsLittleEndian; 127 }; 128 } 129 130 void DWARFExpression::GetDescription(Stream *s, lldb::DescriptionLevel level, 131 addr_t location_list_base_addr, 132 ABI *abi) const { 133 if (IsLocationList()) { 134 // We have a location list 135 lldb::offset_t offset = 0; 136 std::unique_ptr<llvm::DWARFLocationTable> loctable_up = 137 m_dwarf_cu->GetLocationTable(m_data); 138 139 llvm::MCRegisterInfo *MRI = abi ? &abi->GetMCRegisterInfo() : nullptr; 140 llvm::DIDumpOptions DumpOpts; 141 DumpOpts.RecoverableErrorHandler = [&](llvm::Error E) { 142 s->AsRawOstream() << "error: " << toString(std::move(E)); 143 }; 144 loctable_up->dumpLocationList( 145 &offset, s->AsRawOstream(), 146 llvm::object::SectionedAddress{m_loclist_addresses->cu_file_addr}, MRI, 147 DummyDWARFObject(m_data.GetByteOrder() == eByteOrderLittle), nullptr, 148 DumpOpts, s->GetIndentLevel() + 2); 149 } else { 150 // We have a normal location that contains DW_OP location opcodes 151 DumpLocation(s, m_data, level, abi); 152 } 153 } 154 155 static bool ReadRegisterValueAsScalar(RegisterContext *reg_ctx, 156 lldb::RegisterKind reg_kind, 157 uint32_t reg_num, Status *error_ptr, 158 Value &value) { 159 if (reg_ctx == nullptr) { 160 if (error_ptr) 161 error_ptr->SetErrorStringWithFormat("No register context in frame.\n"); 162 } else { 163 uint32_t native_reg = 164 reg_ctx->ConvertRegisterKindToRegisterNumber(reg_kind, reg_num); 165 if (native_reg == LLDB_INVALID_REGNUM) { 166 if (error_ptr) 167 error_ptr->SetErrorStringWithFormat("Unable to convert register " 168 "kind=%u reg_num=%u to a native " 169 "register number.\n", 170 reg_kind, reg_num); 171 } else { 172 const RegisterInfo *reg_info = 173 reg_ctx->GetRegisterInfoAtIndex(native_reg); 174 RegisterValue reg_value; 175 if (reg_ctx->ReadRegister(reg_info, reg_value)) { 176 if (reg_value.GetScalarValue(value.GetScalar())) { 177 value.SetValueType(Value::eValueTypeScalar); 178 value.SetContext(Value::eContextTypeRegisterInfo, 179 const_cast<RegisterInfo *>(reg_info)); 180 if (error_ptr) 181 error_ptr->Clear(); 182 return true; 183 } else { 184 // If we get this error, then we need to implement a value buffer in 185 // the dwarf expression evaluation function... 186 if (error_ptr) 187 error_ptr->SetErrorStringWithFormat( 188 "register %s can't be converted to a scalar value", 189 reg_info->name); 190 } 191 } else { 192 if (error_ptr) 193 error_ptr->SetErrorStringWithFormat("register %s is not available", 194 reg_info->name); 195 } 196 } 197 } 198 return false; 199 } 200 201 /// Return the length in bytes of the set of operands for \p op. No guarantees 202 /// are made on the state of \p data after this call. 203 static offset_t GetOpcodeDataSize(const DataExtractor &data, 204 const lldb::offset_t data_offset, 205 const uint8_t op) { 206 lldb::offset_t offset = data_offset; 207 switch (op) { 208 case DW_OP_addr: 209 case DW_OP_call_ref: // 0x9a 1 address sized offset of DIE (DWARF3) 210 return data.GetAddressByteSize(); 211 212 // Opcodes with no arguments 213 case DW_OP_deref: // 0x06 214 case DW_OP_dup: // 0x12 215 case DW_OP_drop: // 0x13 216 case DW_OP_over: // 0x14 217 case DW_OP_swap: // 0x16 218 case DW_OP_rot: // 0x17 219 case DW_OP_xderef: // 0x18 220 case DW_OP_abs: // 0x19 221 case DW_OP_and: // 0x1a 222 case DW_OP_div: // 0x1b 223 case DW_OP_minus: // 0x1c 224 case DW_OP_mod: // 0x1d 225 case DW_OP_mul: // 0x1e 226 case DW_OP_neg: // 0x1f 227 case DW_OP_not: // 0x20 228 case DW_OP_or: // 0x21 229 case DW_OP_plus: // 0x22 230 case DW_OP_shl: // 0x24 231 case DW_OP_shr: // 0x25 232 case DW_OP_shra: // 0x26 233 case DW_OP_xor: // 0x27 234 case DW_OP_eq: // 0x29 235 case DW_OP_ge: // 0x2a 236 case DW_OP_gt: // 0x2b 237 case DW_OP_le: // 0x2c 238 case DW_OP_lt: // 0x2d 239 case DW_OP_ne: // 0x2e 240 case DW_OP_lit0: // 0x30 241 case DW_OP_lit1: // 0x31 242 case DW_OP_lit2: // 0x32 243 case DW_OP_lit3: // 0x33 244 case DW_OP_lit4: // 0x34 245 case DW_OP_lit5: // 0x35 246 case DW_OP_lit6: // 0x36 247 case DW_OP_lit7: // 0x37 248 case DW_OP_lit8: // 0x38 249 case DW_OP_lit9: // 0x39 250 case DW_OP_lit10: // 0x3A 251 case DW_OP_lit11: // 0x3B 252 case DW_OP_lit12: // 0x3C 253 case DW_OP_lit13: // 0x3D 254 case DW_OP_lit14: // 0x3E 255 case DW_OP_lit15: // 0x3F 256 case DW_OP_lit16: // 0x40 257 case DW_OP_lit17: // 0x41 258 case DW_OP_lit18: // 0x42 259 case DW_OP_lit19: // 0x43 260 case DW_OP_lit20: // 0x44 261 case DW_OP_lit21: // 0x45 262 case DW_OP_lit22: // 0x46 263 case DW_OP_lit23: // 0x47 264 case DW_OP_lit24: // 0x48 265 case DW_OP_lit25: // 0x49 266 case DW_OP_lit26: // 0x4A 267 case DW_OP_lit27: // 0x4B 268 case DW_OP_lit28: // 0x4C 269 case DW_OP_lit29: // 0x4D 270 case DW_OP_lit30: // 0x4E 271 case DW_OP_lit31: // 0x4f 272 case DW_OP_reg0: // 0x50 273 case DW_OP_reg1: // 0x51 274 case DW_OP_reg2: // 0x52 275 case DW_OP_reg3: // 0x53 276 case DW_OP_reg4: // 0x54 277 case DW_OP_reg5: // 0x55 278 case DW_OP_reg6: // 0x56 279 case DW_OP_reg7: // 0x57 280 case DW_OP_reg8: // 0x58 281 case DW_OP_reg9: // 0x59 282 case DW_OP_reg10: // 0x5A 283 case DW_OP_reg11: // 0x5B 284 case DW_OP_reg12: // 0x5C 285 case DW_OP_reg13: // 0x5D 286 case DW_OP_reg14: // 0x5E 287 case DW_OP_reg15: // 0x5F 288 case DW_OP_reg16: // 0x60 289 case DW_OP_reg17: // 0x61 290 case DW_OP_reg18: // 0x62 291 case DW_OP_reg19: // 0x63 292 case DW_OP_reg20: // 0x64 293 case DW_OP_reg21: // 0x65 294 case DW_OP_reg22: // 0x66 295 case DW_OP_reg23: // 0x67 296 case DW_OP_reg24: // 0x68 297 case DW_OP_reg25: // 0x69 298 case DW_OP_reg26: // 0x6A 299 case DW_OP_reg27: // 0x6B 300 case DW_OP_reg28: // 0x6C 301 case DW_OP_reg29: // 0x6D 302 case DW_OP_reg30: // 0x6E 303 case DW_OP_reg31: // 0x6F 304 case DW_OP_nop: // 0x96 305 case DW_OP_push_object_address: // 0x97 DWARF3 306 case DW_OP_form_tls_address: // 0x9b DWARF3 307 case DW_OP_call_frame_cfa: // 0x9c DWARF3 308 case DW_OP_stack_value: // 0x9f DWARF4 309 case DW_OP_GNU_push_tls_address: // 0xe0 GNU extension 310 return 0; 311 312 // Opcodes with a single 1 byte arguments 313 case DW_OP_const1u: // 0x08 1 1-byte constant 314 case DW_OP_const1s: // 0x09 1 1-byte constant 315 case DW_OP_pick: // 0x15 1 1-byte stack index 316 case DW_OP_deref_size: // 0x94 1 1-byte size of data retrieved 317 case DW_OP_xderef_size: // 0x95 1 1-byte size of data retrieved 318 return 1; 319 320 // Opcodes with a single 2 byte arguments 321 case DW_OP_const2u: // 0x0a 1 2-byte constant 322 case DW_OP_const2s: // 0x0b 1 2-byte constant 323 case DW_OP_skip: // 0x2f 1 signed 2-byte constant 324 case DW_OP_bra: // 0x28 1 signed 2-byte constant 325 case DW_OP_call2: // 0x98 1 2-byte offset of DIE (DWARF3) 326 return 2; 327 328 // Opcodes with a single 4 byte arguments 329 case DW_OP_const4u: // 0x0c 1 4-byte constant 330 case DW_OP_const4s: // 0x0d 1 4-byte constant 331 case DW_OP_call4: // 0x99 1 4-byte offset of DIE (DWARF3) 332 return 4; 333 334 // Opcodes with a single 8 byte arguments 335 case DW_OP_const8u: // 0x0e 1 8-byte constant 336 case DW_OP_const8s: // 0x0f 1 8-byte constant 337 return 8; 338 339 // All opcodes that have a single ULEB (signed or unsigned) argument 340 case DW_OP_addrx: // 0xa1 1 ULEB128 index 341 case DW_OP_constu: // 0x10 1 ULEB128 constant 342 case DW_OP_consts: // 0x11 1 SLEB128 constant 343 case DW_OP_plus_uconst: // 0x23 1 ULEB128 addend 344 case DW_OP_breg0: // 0x70 1 ULEB128 register 345 case DW_OP_breg1: // 0x71 1 ULEB128 register 346 case DW_OP_breg2: // 0x72 1 ULEB128 register 347 case DW_OP_breg3: // 0x73 1 ULEB128 register 348 case DW_OP_breg4: // 0x74 1 ULEB128 register 349 case DW_OP_breg5: // 0x75 1 ULEB128 register 350 case DW_OP_breg6: // 0x76 1 ULEB128 register 351 case DW_OP_breg7: // 0x77 1 ULEB128 register 352 case DW_OP_breg8: // 0x78 1 ULEB128 register 353 case DW_OP_breg9: // 0x79 1 ULEB128 register 354 case DW_OP_breg10: // 0x7a 1 ULEB128 register 355 case DW_OP_breg11: // 0x7b 1 ULEB128 register 356 case DW_OP_breg12: // 0x7c 1 ULEB128 register 357 case DW_OP_breg13: // 0x7d 1 ULEB128 register 358 case DW_OP_breg14: // 0x7e 1 ULEB128 register 359 case DW_OP_breg15: // 0x7f 1 ULEB128 register 360 case DW_OP_breg16: // 0x80 1 ULEB128 register 361 case DW_OP_breg17: // 0x81 1 ULEB128 register 362 case DW_OP_breg18: // 0x82 1 ULEB128 register 363 case DW_OP_breg19: // 0x83 1 ULEB128 register 364 case DW_OP_breg20: // 0x84 1 ULEB128 register 365 case DW_OP_breg21: // 0x85 1 ULEB128 register 366 case DW_OP_breg22: // 0x86 1 ULEB128 register 367 case DW_OP_breg23: // 0x87 1 ULEB128 register 368 case DW_OP_breg24: // 0x88 1 ULEB128 register 369 case DW_OP_breg25: // 0x89 1 ULEB128 register 370 case DW_OP_breg26: // 0x8a 1 ULEB128 register 371 case DW_OP_breg27: // 0x8b 1 ULEB128 register 372 case DW_OP_breg28: // 0x8c 1 ULEB128 register 373 case DW_OP_breg29: // 0x8d 1 ULEB128 register 374 case DW_OP_breg30: // 0x8e 1 ULEB128 register 375 case DW_OP_breg31: // 0x8f 1 ULEB128 register 376 case DW_OP_regx: // 0x90 1 ULEB128 register 377 case DW_OP_fbreg: // 0x91 1 SLEB128 offset 378 case DW_OP_piece: // 0x93 1 ULEB128 size of piece addressed 379 case DW_OP_GNU_addr_index: // 0xfb 1 ULEB128 index 380 case DW_OP_GNU_const_index: // 0xfc 1 ULEB128 index 381 data.Skip_LEB128(&offset); 382 return offset - data_offset; 383 384 // All opcodes that have a 2 ULEB (signed or unsigned) arguments 385 case DW_OP_bregx: // 0x92 2 ULEB128 register followed by SLEB128 offset 386 case DW_OP_bit_piece: // 0x9d ULEB128 bit size, ULEB128 bit offset (DWARF3); 387 data.Skip_LEB128(&offset); 388 data.Skip_LEB128(&offset); 389 return offset - data_offset; 390 391 case DW_OP_implicit_value: // 0x9e ULEB128 size followed by block of that size 392 // (DWARF4) 393 { 394 uint64_t block_len = data.Skip_LEB128(&offset); 395 offset += block_len; 396 return offset - data_offset; 397 } 398 399 case DW_OP_GNU_entry_value: 400 case DW_OP_entry_value: // 0xa3 ULEB128 size + variable-length block 401 { 402 uint64_t subexpr_len = data.GetULEB128(&offset); 403 return (offset - data_offset) + subexpr_len; 404 } 405 406 default: 407 break; 408 } 409 return LLDB_INVALID_OFFSET; 410 } 411 412 lldb::addr_t DWARFExpression::GetLocation_DW_OP_addr(uint32_t op_addr_idx, 413 bool &error) const { 414 error = false; 415 if (IsLocationList()) 416 return LLDB_INVALID_ADDRESS; 417 lldb::offset_t offset = 0; 418 uint32_t curr_op_addr_idx = 0; 419 while (m_data.ValidOffset(offset)) { 420 const uint8_t op = m_data.GetU8(&offset); 421 422 if (op == DW_OP_addr) { 423 const lldb::addr_t op_file_addr = m_data.GetAddress(&offset); 424 if (curr_op_addr_idx == op_addr_idx) 425 return op_file_addr; 426 else 427 ++curr_op_addr_idx; 428 } else if (op == DW_OP_GNU_addr_index || op == DW_OP_addrx) { 429 uint64_t index = m_data.GetULEB128(&offset); 430 if (curr_op_addr_idx == op_addr_idx) { 431 if (!m_dwarf_cu) { 432 error = true; 433 break; 434 } 435 436 return ReadAddressFromDebugAddrSection(m_dwarf_cu, index); 437 } else 438 ++curr_op_addr_idx; 439 } else { 440 const offset_t op_arg_size = GetOpcodeDataSize(m_data, offset, op); 441 if (op_arg_size == LLDB_INVALID_OFFSET) { 442 error = true; 443 break; 444 } 445 offset += op_arg_size; 446 } 447 } 448 return LLDB_INVALID_ADDRESS; 449 } 450 451 bool DWARFExpression::Update_DW_OP_addr(lldb::addr_t file_addr) { 452 if (IsLocationList()) 453 return false; 454 lldb::offset_t offset = 0; 455 while (m_data.ValidOffset(offset)) { 456 const uint8_t op = m_data.GetU8(&offset); 457 458 if (op == DW_OP_addr) { 459 const uint32_t addr_byte_size = m_data.GetAddressByteSize(); 460 // We have to make a copy of the data as we don't know if this data is 461 // from a read only memory mapped buffer, so we duplicate all of the data 462 // first, then modify it, and if all goes well, we then replace the data 463 // for this expression 464 465 // So first we copy the data into a heap buffer 466 std::unique_ptr<DataBufferHeap> head_data_up( 467 new DataBufferHeap(m_data.GetDataStart(), m_data.GetByteSize())); 468 469 // Make en encoder so we can write the address into the buffer using the 470 // correct byte order (endianness) 471 DataEncoder encoder(head_data_up->GetBytes(), head_data_up->GetByteSize(), 472 m_data.GetByteOrder(), addr_byte_size); 473 474 // Replace the address in the new buffer 475 if (encoder.PutUnsigned(offset, addr_byte_size, file_addr) == UINT32_MAX) 476 return false; 477 478 // All went well, so now we can reset the data using a shared pointer to 479 // the heap data so "m_data" will now correctly manage the heap data. 480 m_data.SetData(DataBufferSP(head_data_up.release())); 481 return true; 482 } else { 483 const offset_t op_arg_size = GetOpcodeDataSize(m_data, offset, op); 484 if (op_arg_size == LLDB_INVALID_OFFSET) 485 break; 486 offset += op_arg_size; 487 } 488 } 489 return false; 490 } 491 492 bool DWARFExpression::ContainsThreadLocalStorage() const { 493 // We are assuming for now that any thread local variable will not have a 494 // location list. This has been true for all thread local variables we have 495 // seen so far produced by any compiler. 496 if (IsLocationList()) 497 return false; 498 lldb::offset_t offset = 0; 499 while (m_data.ValidOffset(offset)) { 500 const uint8_t op = m_data.GetU8(&offset); 501 502 if (op == DW_OP_form_tls_address || op == DW_OP_GNU_push_tls_address) 503 return true; 504 const offset_t op_arg_size = GetOpcodeDataSize(m_data, offset, op); 505 if (op_arg_size == LLDB_INVALID_OFFSET) 506 return false; 507 else 508 offset += op_arg_size; 509 } 510 return false; 511 } 512 bool DWARFExpression::LinkThreadLocalStorage( 513 lldb::ModuleSP new_module_sp, 514 std::function<lldb::addr_t(lldb::addr_t file_addr)> const 515 &link_address_callback) { 516 // We are assuming for now that any thread local variable will not have a 517 // location list. This has been true for all thread local variables we have 518 // seen so far produced by any compiler. 519 if (IsLocationList()) 520 return false; 521 522 const uint32_t addr_byte_size = m_data.GetAddressByteSize(); 523 // We have to make a copy of the data as we don't know if this data is from a 524 // read only memory mapped buffer, so we duplicate all of the data first, 525 // then modify it, and if all goes well, we then replace the data for this 526 // expression 527 528 // So first we copy the data into a heap buffer 529 std::shared_ptr<DataBufferHeap> heap_data_sp( 530 new DataBufferHeap(m_data.GetDataStart(), m_data.GetByteSize())); 531 532 // Make en encoder so we can write the address into the buffer using the 533 // correct byte order (endianness) 534 DataEncoder encoder(heap_data_sp->GetBytes(), heap_data_sp->GetByteSize(), 535 m_data.GetByteOrder(), addr_byte_size); 536 537 lldb::offset_t offset = 0; 538 lldb::offset_t const_offset = 0; 539 lldb::addr_t const_value = 0; 540 size_t const_byte_size = 0; 541 while (m_data.ValidOffset(offset)) { 542 const uint8_t op = m_data.GetU8(&offset); 543 544 bool decoded_data = false; 545 switch (op) { 546 case DW_OP_const4u: 547 // Remember the const offset in case we later have a 548 // DW_OP_form_tls_address or DW_OP_GNU_push_tls_address 549 const_offset = offset; 550 const_value = m_data.GetU32(&offset); 551 decoded_data = true; 552 const_byte_size = 4; 553 break; 554 555 case DW_OP_const8u: 556 // Remember the const offset in case we later have a 557 // DW_OP_form_tls_address or DW_OP_GNU_push_tls_address 558 const_offset = offset; 559 const_value = m_data.GetU64(&offset); 560 decoded_data = true; 561 const_byte_size = 8; 562 break; 563 564 case DW_OP_form_tls_address: 565 case DW_OP_GNU_push_tls_address: 566 // DW_OP_form_tls_address and DW_OP_GNU_push_tls_address must be preceded 567 // by a file address on the stack. We assume that DW_OP_const4u or 568 // DW_OP_const8u is used for these values, and we check that the last 569 // opcode we got before either of these was DW_OP_const4u or 570 // DW_OP_const8u. If so, then we can link the value accodingly. For 571 // Darwin, the value in the DW_OP_const4u or DW_OP_const8u is the file 572 // address of a structure that contains a function pointer, the pthread 573 // key and the offset into the data pointed to by the pthread key. So we 574 // must link this address and also set the module of this expression to 575 // the new_module_sp so we can resolve the file address correctly 576 if (const_byte_size > 0) { 577 lldb::addr_t linked_file_addr = link_address_callback(const_value); 578 if (linked_file_addr == LLDB_INVALID_ADDRESS) 579 return false; 580 // Replace the address in the new buffer 581 if (encoder.PutUnsigned(const_offset, const_byte_size, 582 linked_file_addr) == UINT32_MAX) 583 return false; 584 } 585 break; 586 587 default: 588 const_offset = 0; 589 const_value = 0; 590 const_byte_size = 0; 591 break; 592 } 593 594 if (!decoded_data) { 595 const offset_t op_arg_size = GetOpcodeDataSize(m_data, offset, op); 596 if (op_arg_size == LLDB_INVALID_OFFSET) 597 return false; 598 else 599 offset += op_arg_size; 600 } 601 } 602 603 // If we linked the TLS address correctly, update the module so that when the 604 // expression is evaluated it can resolve the file address to a load address 605 // and read the 606 // TLS data 607 m_module_wp = new_module_sp; 608 m_data.SetData(heap_data_sp); 609 return true; 610 } 611 612 bool DWARFExpression::LocationListContainsAddress(addr_t func_load_addr, 613 lldb::addr_t addr) const { 614 if (func_load_addr == LLDB_INVALID_ADDRESS || addr == LLDB_INVALID_ADDRESS) 615 return false; 616 617 if (!IsLocationList()) 618 return false; 619 620 return GetLocationExpression(func_load_addr, addr) != llvm::None; 621 } 622 623 bool DWARFExpression::DumpLocationForAddress(Stream *s, 624 lldb::DescriptionLevel level, 625 addr_t func_load_addr, 626 addr_t address, ABI *abi) { 627 if (!IsLocationList()) { 628 DumpLocation(s, m_data, level, abi); 629 return true; 630 } 631 if (llvm::Optional<DataExtractor> expr = 632 GetLocationExpression(func_load_addr, address)) { 633 DumpLocation(s, *expr, level, abi); 634 return true; 635 } 636 return false; 637 } 638 639 static bool Evaluate_DW_OP_entry_value(std::vector<Value> &stack, 640 ExecutionContext *exe_ctx, 641 RegisterContext *reg_ctx, 642 const DataExtractor &opcodes, 643 lldb::offset_t &opcode_offset, 644 Status *error_ptr, Log *log) { 645 // DW_OP_entry_value(sub-expr) describes the location a variable had upon 646 // function entry: this variable location is presumed to be optimized out at 647 // the current PC value. The caller of the function may have call site 648 // information that describes an alternate location for the variable (e.g. a 649 // constant literal, or a spilled stack value) in the parent frame. 650 // 651 // Example (this is pseudo-code & pseudo-DWARF, but hopefully illustrative): 652 // 653 // void child(int &sink, int x) { 654 // ... 655 // /* "x" gets optimized out. */ 656 // 657 // /* The location of "x" here is: DW_OP_entry_value($reg2). */ 658 // ++sink; 659 // } 660 // 661 // void parent() { 662 // int sink; 663 // 664 // /* 665 // * The callsite information emitted here is: 666 // * 667 // * DW_TAG_call_site 668 // * DW_AT_return_pc ... (for "child(sink, 123);") 669 // * DW_TAG_call_site_parameter (for "sink") 670 // * DW_AT_location ($reg1) 671 // * DW_AT_call_value ($SP - 8) 672 // * DW_TAG_call_site_parameter (for "x") 673 // * DW_AT_location ($reg2) 674 // * DW_AT_call_value ($literal 123) 675 // * 676 // * DW_TAG_call_site 677 // * DW_AT_return_pc ... (for "child(sink, 456);") 678 // * ... 679 // */ 680 // child(sink, 123); 681 // child(sink, 456); 682 // } 683 // 684 // When the program stops at "++sink" within `child`, the debugger determines 685 // the call site by analyzing the return address. Once the call site is found, 686 // the debugger determines which parameter is referenced by DW_OP_entry_value 687 // and evaluates the corresponding location for that parameter in `parent`. 688 689 // 1. Find the function which pushed the current frame onto the stack. 690 if ((!exe_ctx || !exe_ctx->HasTargetScope()) || !reg_ctx) { 691 LLDB_LOG(log, "Evaluate_DW_OP_entry_value: no exe/reg context"); 692 return false; 693 } 694 695 StackFrame *current_frame = exe_ctx->GetFramePtr(); 696 Thread *thread = exe_ctx->GetThreadPtr(); 697 if (!current_frame || !thread) { 698 LLDB_LOG(log, "Evaluate_DW_OP_entry_value: no current frame/thread"); 699 return false; 700 } 701 702 Target &target = exe_ctx->GetTargetRef(); 703 StackFrameSP parent_frame = nullptr; 704 addr_t return_pc = LLDB_INVALID_ADDRESS; 705 uint32_t current_frame_idx = current_frame->GetFrameIndex(); 706 uint32_t num_frames = thread->GetStackFrameCount(); 707 for (uint32_t parent_frame_idx = current_frame_idx + 1; 708 parent_frame_idx < num_frames; ++parent_frame_idx) { 709 parent_frame = thread->GetStackFrameAtIndex(parent_frame_idx); 710 // Require a valid sequence of frames. 711 if (!parent_frame) 712 break; 713 714 // Record the first valid return address, even if this is an inlined frame, 715 // in order to look up the associated call edge in the first non-inlined 716 // parent frame. 717 if (return_pc == LLDB_INVALID_ADDRESS) { 718 return_pc = parent_frame->GetFrameCodeAddress().GetLoadAddress(&target); 719 LLDB_LOG(log, 720 "Evaluate_DW_OP_entry_value: immediate ancestor with pc = {0:x}", 721 return_pc); 722 } 723 724 // If we've found an inlined frame, skip it (these have no call site 725 // parameters). 726 if (parent_frame->IsInlined()) 727 continue; 728 729 // We've found the first non-inlined parent frame. 730 break; 731 } 732 if (!parent_frame || !parent_frame->GetRegisterContext()) { 733 LLDB_LOG(log, "Evaluate_DW_OP_entry_value: no parent frame with reg ctx"); 734 return false; 735 } 736 737 Function *parent_func = 738 parent_frame->GetSymbolContext(eSymbolContextFunction).function; 739 if (!parent_func) { 740 LLDB_LOG(log, "Evaluate_DW_OP_entry_value: no parent function"); 741 return false; 742 } 743 744 // 2. Find the call edge in the parent function responsible for creating the 745 // current activation. 746 Function *current_func = 747 current_frame->GetSymbolContext(eSymbolContextFunction).function; 748 if (!current_func) { 749 LLDB_LOG(log, "Evaluate_DW_OP_entry_value: no current function"); 750 return false; 751 } 752 753 CallEdge *call_edge = nullptr; 754 ModuleList &modlist = target.GetImages(); 755 ExecutionContext parent_exe_ctx = *exe_ctx; 756 parent_exe_ctx.SetFrameSP(parent_frame); 757 if (!parent_frame->IsArtificial()) { 758 // If the parent frame is not artificial, the current activation may be 759 // produced by an ambiguous tail call. In this case, refuse to proceed. 760 call_edge = parent_func->GetCallEdgeForReturnAddress(return_pc, target); 761 if (!call_edge) { 762 LLDB_LOG(log, 763 "Evaluate_DW_OP_entry_value: no call edge for retn-pc = {0:x} " 764 "in parent frame {1}", 765 return_pc, parent_func->GetName()); 766 return false; 767 } 768 Function *callee_func = call_edge->GetCallee(modlist, parent_exe_ctx); 769 if (callee_func != current_func) { 770 LLDB_LOG(log, "Evaluate_DW_OP_entry_value: ambiguous call sequence, " 771 "can't find real parent frame"); 772 return false; 773 } 774 } else { 775 // The StackFrameList solver machinery has deduced that an unambiguous tail 776 // call sequence that produced the current activation. The first edge in 777 // the parent that points to the current function must be valid. 778 for (auto &edge : parent_func->GetTailCallingEdges()) { 779 if (edge->GetCallee(modlist, parent_exe_ctx) == current_func) { 780 call_edge = edge.get(); 781 break; 782 } 783 } 784 } 785 if (!call_edge) { 786 LLDB_LOG(log, "Evaluate_DW_OP_entry_value: no unambiguous edge from parent " 787 "to current function"); 788 return false; 789 } 790 791 // 3. Attempt to locate the DW_OP_entry_value expression in the set of 792 // available call site parameters. If found, evaluate the corresponding 793 // parameter in the context of the parent frame. 794 const uint32_t subexpr_len = opcodes.GetULEB128(&opcode_offset); 795 const void *subexpr_data = opcodes.GetData(&opcode_offset, subexpr_len); 796 if (!subexpr_data) { 797 LLDB_LOG(log, "Evaluate_DW_OP_entry_value: subexpr could not be read"); 798 return false; 799 } 800 801 const CallSiteParameter *matched_param = nullptr; 802 for (const CallSiteParameter ¶m : call_edge->GetCallSiteParameters()) { 803 DataExtractor param_subexpr_extractor; 804 if (!param.LocationInCallee.GetExpressionData(param_subexpr_extractor)) 805 continue; 806 lldb::offset_t param_subexpr_offset = 0; 807 const void *param_subexpr_data = 808 param_subexpr_extractor.GetData(¶m_subexpr_offset, subexpr_len); 809 if (!param_subexpr_data || 810 param_subexpr_extractor.BytesLeft(param_subexpr_offset) != 0) 811 continue; 812 813 // At this point, the DW_OP_entry_value sub-expression and the callee-side 814 // expression in the call site parameter are known to have the same length. 815 // Check whether they are equal. 816 // 817 // Note that an equality check is sufficient: the contents of the 818 // DW_OP_entry_value subexpression are only used to identify the right call 819 // site parameter in the parent, and do not require any special handling. 820 if (memcmp(subexpr_data, param_subexpr_data, subexpr_len) == 0) { 821 matched_param = ¶m; 822 break; 823 } 824 } 825 if (!matched_param) { 826 LLDB_LOG(log, 827 "Evaluate_DW_OP_entry_value: no matching call site param found"); 828 return false; 829 } 830 831 // TODO: Add support for DW_OP_push_object_address within a DW_OP_entry_value 832 // subexpresion whenever llvm does. 833 Value result; 834 const DWARFExpression ¶m_expr = matched_param->LocationInCaller; 835 if (!param_expr.Evaluate(&parent_exe_ctx, 836 parent_frame->GetRegisterContext().get(), 837 /*loclist_base_addr=*/LLDB_INVALID_ADDRESS, 838 /*initial_value_ptr=*/nullptr, 839 /*object_address_ptr=*/nullptr, result, error_ptr)) { 840 LLDB_LOG(log, 841 "Evaluate_DW_OP_entry_value: call site param evaluation failed"); 842 return false; 843 } 844 845 stack.push_back(result); 846 return true; 847 } 848 849 bool DWARFExpression::Evaluate(ExecutionContextScope *exe_scope, 850 lldb::addr_t loclist_base_load_addr, 851 const Value *initial_value_ptr, 852 const Value *object_address_ptr, Value &result, 853 Status *error_ptr) const { 854 ExecutionContext exe_ctx(exe_scope); 855 return Evaluate(&exe_ctx, nullptr, loclist_base_load_addr, initial_value_ptr, 856 object_address_ptr, result, error_ptr); 857 } 858 859 bool DWARFExpression::Evaluate(ExecutionContext *exe_ctx, 860 RegisterContext *reg_ctx, 861 lldb::addr_t func_load_addr, 862 const Value *initial_value_ptr, 863 const Value *object_address_ptr, Value &result, 864 Status *error_ptr) const { 865 ModuleSP module_sp = m_module_wp.lock(); 866 867 if (IsLocationList()) { 868 addr_t pc; 869 StackFrame *frame = nullptr; 870 if (reg_ctx) 871 pc = reg_ctx->GetPC(); 872 else { 873 frame = exe_ctx->GetFramePtr(); 874 if (!frame) 875 return false; 876 RegisterContextSP reg_ctx_sp = frame->GetRegisterContext(); 877 if (!reg_ctx_sp) 878 return false; 879 pc = reg_ctx_sp->GetPC(); 880 } 881 882 if (func_load_addr != LLDB_INVALID_ADDRESS) { 883 if (pc == LLDB_INVALID_ADDRESS) { 884 if (error_ptr) 885 error_ptr->SetErrorString("Invalid PC in frame."); 886 return false; 887 } 888 889 if (llvm::Optional<DataExtractor> expr = 890 GetLocationExpression(func_load_addr, pc)) { 891 return DWARFExpression::Evaluate( 892 exe_ctx, reg_ctx, module_sp, *expr, m_dwarf_cu, m_reg_kind, 893 initial_value_ptr, object_address_ptr, result, error_ptr); 894 } 895 } 896 if (error_ptr) 897 error_ptr->SetErrorString("variable not available"); 898 return false; 899 } 900 901 // Not a location list, just a single expression. 902 return DWARFExpression::Evaluate(exe_ctx, reg_ctx, module_sp, m_data, 903 m_dwarf_cu, m_reg_kind, initial_value_ptr, 904 object_address_ptr, result, error_ptr); 905 } 906 907 bool DWARFExpression::Evaluate( 908 ExecutionContext *exe_ctx, RegisterContext *reg_ctx, 909 lldb::ModuleSP module_sp, const DataExtractor &opcodes, 910 const DWARFUnit *dwarf_cu, const lldb::RegisterKind reg_kind, 911 const Value *initial_value_ptr, const Value *object_address_ptr, 912 Value &result, Status *error_ptr) { 913 914 if (opcodes.GetByteSize() == 0) { 915 if (error_ptr) 916 error_ptr->SetErrorString( 917 "no location, value may have been optimized out"); 918 return false; 919 } 920 std::vector<Value> stack; 921 922 Process *process = nullptr; 923 StackFrame *frame = nullptr; 924 925 if (exe_ctx) { 926 process = exe_ctx->GetProcessPtr(); 927 frame = exe_ctx->GetFramePtr(); 928 } 929 if (reg_ctx == nullptr && frame) 930 reg_ctx = frame->GetRegisterContext().get(); 931 932 if (initial_value_ptr) 933 stack.push_back(*initial_value_ptr); 934 935 lldb::offset_t offset = 0; 936 Value tmp; 937 uint32_t reg_num; 938 939 /// Insertion point for evaluating multi-piece expression. 940 uint64_t op_piece_offset = 0; 941 Value pieces; // Used for DW_OP_piece 942 943 Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS)); 944 945 while (opcodes.ValidOffset(offset)) { 946 const lldb::offset_t op_offset = offset; 947 const uint8_t op = opcodes.GetU8(&offset); 948 949 if (log && log->GetVerbose()) { 950 size_t count = stack.size(); 951 LLDB_LOGF(log, "Stack before operation has %" PRIu64 " values:", 952 (uint64_t)count); 953 for (size_t i = 0; i < count; ++i) { 954 StreamString new_value; 955 new_value.Printf("[%" PRIu64 "]", (uint64_t)i); 956 stack[i].Dump(&new_value); 957 LLDB_LOGF(log, " %s", new_value.GetData()); 958 } 959 LLDB_LOGF(log, "0x%8.8" PRIx64 ": %s", op_offset, 960 DW_OP_value_to_name(op)); 961 } 962 963 switch (op) { 964 // The DW_OP_addr operation has a single operand that encodes a machine 965 // address and whose size is the size of an address on the target machine. 966 case DW_OP_addr: 967 stack.push_back(Scalar(opcodes.GetAddress(&offset))); 968 stack.back().SetValueType(Value::eValueTypeFileAddress); 969 // Convert the file address to a load address, so subsequent 970 // DWARF operators can operate on it. 971 if (frame) 972 stack.back().ConvertToLoadAddress(module_sp.get(), 973 frame->CalculateTarget().get()); 974 break; 975 976 // The DW_OP_addr_sect_offset4 is used for any location expressions in 977 // shared libraries that have a location like: 978 // DW_OP_addr(0x1000) 979 // If this address resides in a shared library, then this virtual address 980 // won't make sense when it is evaluated in the context of a running 981 // process where shared libraries have been slid. To account for this, this 982 // new address type where we can store the section pointer and a 4 byte 983 // offset. 984 // case DW_OP_addr_sect_offset4: 985 // { 986 // result_type = eResultTypeFileAddress; 987 // lldb::Section *sect = (lldb::Section 988 // *)opcodes.GetMaxU64(&offset, sizeof(void *)); 989 // lldb::addr_t sect_offset = opcodes.GetU32(&offset); 990 // 991 // Address so_addr (sect, sect_offset); 992 // lldb::addr_t load_addr = so_addr.GetLoadAddress(); 993 // if (load_addr != LLDB_INVALID_ADDRESS) 994 // { 995 // // We successfully resolve a file address to a load 996 // // address. 997 // stack.push_back(load_addr); 998 // break; 999 // } 1000 // else 1001 // { 1002 // // We were able 1003 // if (error_ptr) 1004 // error_ptr->SetErrorStringWithFormat ("Section %s in 1005 // %s is not currently loaded.\n", 1006 // sect->GetName().AsCString(), 1007 // sect->GetModule()->GetFileSpec().GetFilename().AsCString()); 1008 // return false; 1009 // } 1010 // } 1011 // break; 1012 1013 // OPCODE: DW_OP_deref 1014 // OPERANDS: none 1015 // DESCRIPTION: Pops the top stack entry and treats it as an address. 1016 // The value retrieved from that address is pushed. The size of the data 1017 // retrieved from the dereferenced address is the size of an address on the 1018 // target machine. 1019 case DW_OP_deref: { 1020 if (stack.empty()) { 1021 if (error_ptr) 1022 error_ptr->SetErrorString("Expression stack empty for DW_OP_deref."); 1023 return false; 1024 } 1025 Value::ValueType value_type = stack.back().GetValueType(); 1026 switch (value_type) { 1027 case Value::eValueTypeHostAddress: { 1028 void *src = (void *)stack.back().GetScalar().ULongLong(); 1029 intptr_t ptr; 1030 ::memcpy(&ptr, src, sizeof(void *)); 1031 stack.back().GetScalar() = ptr; 1032 stack.back().ClearContext(); 1033 } break; 1034 case Value::eValueTypeFileAddress: { 1035 auto file_addr = stack.back().GetScalar().ULongLong( 1036 LLDB_INVALID_ADDRESS); 1037 if (!module_sp) { 1038 if (error_ptr) 1039 error_ptr->SetErrorStringWithFormat( 1040 "need module to resolve file address for DW_OP_deref"); 1041 return false; 1042 } 1043 Address so_addr; 1044 if (!module_sp->ResolveFileAddress(file_addr, so_addr)) { 1045 if (error_ptr) 1046 error_ptr->SetErrorStringWithFormat( 1047 "failed to resolve file address in module"); 1048 return false; 1049 } 1050 addr_t load_Addr = so_addr.GetLoadAddress(exe_ctx->GetTargetPtr()); 1051 if (load_Addr == LLDB_INVALID_ADDRESS) { 1052 if (error_ptr) 1053 error_ptr->SetErrorStringWithFormat( 1054 "failed to resolve load address"); 1055 return false; 1056 } 1057 stack.back().GetScalar() = load_Addr; 1058 stack.back().SetValueType(Value::eValueTypeLoadAddress); 1059 // Fall through to load address code below... 1060 } LLVM_FALLTHROUGH; 1061 case Value::eValueTypeLoadAddress: 1062 if (exe_ctx) { 1063 if (process) { 1064 lldb::addr_t pointer_addr = 1065 stack.back().GetScalar().ULongLong(LLDB_INVALID_ADDRESS); 1066 Status error; 1067 lldb::addr_t pointer_value = 1068 process->ReadPointerFromMemory(pointer_addr, error); 1069 if (pointer_value != LLDB_INVALID_ADDRESS) { 1070 stack.back().GetScalar() = pointer_value; 1071 stack.back().ClearContext(); 1072 } else { 1073 if (error_ptr) 1074 error_ptr->SetErrorStringWithFormat( 1075 "Failed to dereference pointer from 0x%" PRIx64 1076 " for DW_OP_deref: %s\n", 1077 pointer_addr, error.AsCString()); 1078 return false; 1079 } 1080 } else { 1081 if (error_ptr) 1082 error_ptr->SetErrorStringWithFormat( 1083 "NULL process for DW_OP_deref.\n"); 1084 return false; 1085 } 1086 } else { 1087 if (error_ptr) 1088 error_ptr->SetErrorStringWithFormat( 1089 "NULL execution context for DW_OP_deref.\n"); 1090 return false; 1091 } 1092 break; 1093 1094 default: 1095 break; 1096 } 1097 1098 } break; 1099 1100 // OPCODE: DW_OP_deref_size 1101 // OPERANDS: 1 1102 // 1 - uint8_t that specifies the size of the data to dereference. 1103 // DESCRIPTION: Behaves like the DW_OP_deref operation: it pops the top 1104 // stack entry and treats it as an address. The value retrieved from that 1105 // address is pushed. In the DW_OP_deref_size operation, however, the size 1106 // in bytes of the data retrieved from the dereferenced address is 1107 // specified by the single operand. This operand is a 1-byte unsigned 1108 // integral constant whose value may not be larger than the size of an 1109 // address on the target machine. The data retrieved is zero extended to 1110 // the size of an address on the target machine before being pushed on the 1111 // expression stack. 1112 case DW_OP_deref_size: { 1113 if (stack.empty()) { 1114 if (error_ptr) 1115 error_ptr->SetErrorString( 1116 "Expression stack empty for DW_OP_deref_size."); 1117 return false; 1118 } 1119 uint8_t size = opcodes.GetU8(&offset); 1120 Value::ValueType value_type = stack.back().GetValueType(); 1121 switch (value_type) { 1122 case Value::eValueTypeHostAddress: { 1123 void *src = (void *)stack.back().GetScalar().ULongLong(); 1124 intptr_t ptr; 1125 ::memcpy(&ptr, src, sizeof(void *)); 1126 // I can't decide whether the size operand should apply to the bytes in 1127 // their 1128 // lldb-host endianness or the target endianness.. I doubt this'll ever 1129 // come up but I'll opt for assuming big endian regardless. 1130 switch (size) { 1131 case 1: 1132 ptr = ptr & 0xff; 1133 break; 1134 case 2: 1135 ptr = ptr & 0xffff; 1136 break; 1137 case 3: 1138 ptr = ptr & 0xffffff; 1139 break; 1140 case 4: 1141 ptr = ptr & 0xffffffff; 1142 break; 1143 // the casts are added to work around the case where intptr_t is a 32 1144 // bit quantity; 1145 // presumably we won't hit the 5..7 cases if (void*) is 32-bits in this 1146 // program. 1147 case 5: 1148 ptr = (intptr_t)ptr & 0xffffffffffULL; 1149 break; 1150 case 6: 1151 ptr = (intptr_t)ptr & 0xffffffffffffULL; 1152 break; 1153 case 7: 1154 ptr = (intptr_t)ptr & 0xffffffffffffffULL; 1155 break; 1156 default: 1157 break; 1158 } 1159 stack.back().GetScalar() = ptr; 1160 stack.back().ClearContext(); 1161 } break; 1162 case Value::eValueTypeLoadAddress: 1163 if (exe_ctx) { 1164 if (process) { 1165 lldb::addr_t pointer_addr = 1166 stack.back().GetScalar().ULongLong(LLDB_INVALID_ADDRESS); 1167 uint8_t addr_bytes[sizeof(lldb::addr_t)]; 1168 Status error; 1169 if (process->ReadMemory(pointer_addr, &addr_bytes, size, error) == 1170 size) { 1171 DataExtractor addr_data(addr_bytes, sizeof(addr_bytes), 1172 process->GetByteOrder(), size); 1173 lldb::offset_t addr_data_offset = 0; 1174 switch (size) { 1175 case 1: 1176 stack.back().GetScalar() = addr_data.GetU8(&addr_data_offset); 1177 break; 1178 case 2: 1179 stack.back().GetScalar() = addr_data.GetU16(&addr_data_offset); 1180 break; 1181 case 4: 1182 stack.back().GetScalar() = addr_data.GetU32(&addr_data_offset); 1183 break; 1184 case 8: 1185 stack.back().GetScalar() = addr_data.GetU64(&addr_data_offset); 1186 break; 1187 default: 1188 stack.back().GetScalar() = 1189 addr_data.GetAddress(&addr_data_offset); 1190 } 1191 stack.back().ClearContext(); 1192 } else { 1193 if (error_ptr) 1194 error_ptr->SetErrorStringWithFormat( 1195 "Failed to dereference pointer from 0x%" PRIx64 1196 " for DW_OP_deref: %s\n", 1197 pointer_addr, error.AsCString()); 1198 return false; 1199 } 1200 } else { 1201 if (error_ptr) 1202 error_ptr->SetErrorStringWithFormat( 1203 "NULL process for DW_OP_deref.\n"); 1204 return false; 1205 } 1206 } else { 1207 if (error_ptr) 1208 error_ptr->SetErrorStringWithFormat( 1209 "NULL execution context for DW_OP_deref.\n"); 1210 return false; 1211 } 1212 break; 1213 1214 default: 1215 break; 1216 } 1217 1218 } break; 1219 1220 // OPCODE: DW_OP_xderef_size 1221 // OPERANDS: 1 1222 // 1 - uint8_t that specifies the size of the data to dereference. 1223 // DESCRIPTION: Behaves like the DW_OP_xderef operation: the entry at 1224 // the top of the stack is treated as an address. The second stack entry is 1225 // treated as an "address space identifier" for those architectures that 1226 // support multiple address spaces. The top two stack elements are popped, 1227 // a data item is retrieved through an implementation-defined address 1228 // calculation and pushed as the new stack top. In the DW_OP_xderef_size 1229 // operation, however, the size in bytes of the data retrieved from the 1230 // dereferenced address is specified by the single operand. This operand is 1231 // a 1-byte unsigned integral constant whose value may not be larger than 1232 // the size of an address on the target machine. The data retrieved is zero 1233 // extended to the size of an address on the target machine before being 1234 // pushed on the expression stack. 1235 case DW_OP_xderef_size: 1236 if (error_ptr) 1237 error_ptr->SetErrorString("Unimplemented opcode: DW_OP_xderef_size."); 1238 return false; 1239 // OPCODE: DW_OP_xderef 1240 // OPERANDS: none 1241 // DESCRIPTION: Provides an extended dereference mechanism. The entry at 1242 // the top of the stack is treated as an address. The second stack entry is 1243 // treated as an "address space identifier" for those architectures that 1244 // support multiple address spaces. The top two stack elements are popped, 1245 // a data item is retrieved through an implementation-defined address 1246 // calculation and pushed as the new stack top. The size of the data 1247 // retrieved from the dereferenced address is the size of an address on the 1248 // target machine. 1249 case DW_OP_xderef: 1250 if (error_ptr) 1251 error_ptr->SetErrorString("Unimplemented opcode: DW_OP_xderef."); 1252 return false; 1253 1254 // All DW_OP_constXXX opcodes have a single operand as noted below: 1255 // 1256 // Opcode Operand 1 1257 // DW_OP_const1u 1-byte unsigned integer constant DW_OP_const1s 1258 // 1-byte signed integer constant DW_OP_const2u 2-byte unsigned integer 1259 // constant DW_OP_const2s 2-byte signed integer constant DW_OP_const4u 1260 // 4-byte unsigned integer constant DW_OP_const4s 4-byte signed integer 1261 // constant DW_OP_const8u 8-byte unsigned integer constant DW_OP_const8s 1262 // 8-byte signed integer constant DW_OP_constu unsigned LEB128 integer 1263 // constant DW_OP_consts signed LEB128 integer constant 1264 case DW_OP_const1u: 1265 stack.push_back(Scalar((uint8_t)opcodes.GetU8(&offset))); 1266 break; 1267 case DW_OP_const1s: 1268 stack.push_back(Scalar((int8_t)opcodes.GetU8(&offset))); 1269 break; 1270 case DW_OP_const2u: 1271 stack.push_back(Scalar((uint16_t)opcodes.GetU16(&offset))); 1272 break; 1273 case DW_OP_const2s: 1274 stack.push_back(Scalar((int16_t)opcodes.GetU16(&offset))); 1275 break; 1276 case DW_OP_const4u: 1277 stack.push_back(Scalar((uint32_t)opcodes.GetU32(&offset))); 1278 break; 1279 case DW_OP_const4s: 1280 stack.push_back(Scalar((int32_t)opcodes.GetU32(&offset))); 1281 break; 1282 case DW_OP_const8u: 1283 stack.push_back(Scalar((uint64_t)opcodes.GetU64(&offset))); 1284 break; 1285 case DW_OP_const8s: 1286 stack.push_back(Scalar((int64_t)opcodes.GetU64(&offset))); 1287 break; 1288 case DW_OP_constu: 1289 stack.push_back(Scalar(opcodes.GetULEB128(&offset))); 1290 break; 1291 case DW_OP_consts: 1292 stack.push_back(Scalar(opcodes.GetSLEB128(&offset))); 1293 break; 1294 1295 // OPCODE: DW_OP_dup 1296 // OPERANDS: none 1297 // DESCRIPTION: duplicates the value at the top of the stack 1298 case DW_OP_dup: 1299 if (stack.empty()) { 1300 if (error_ptr) 1301 error_ptr->SetErrorString("Expression stack empty for DW_OP_dup."); 1302 return false; 1303 } else 1304 stack.push_back(stack.back()); 1305 break; 1306 1307 // OPCODE: DW_OP_drop 1308 // OPERANDS: none 1309 // DESCRIPTION: pops the value at the top of the stack 1310 case DW_OP_drop: 1311 if (stack.empty()) { 1312 if (error_ptr) 1313 error_ptr->SetErrorString("Expression stack empty for DW_OP_drop."); 1314 return false; 1315 } else 1316 stack.pop_back(); 1317 break; 1318 1319 // OPCODE: DW_OP_over 1320 // OPERANDS: none 1321 // DESCRIPTION: Duplicates the entry currently second in the stack at 1322 // the top of the stack. 1323 case DW_OP_over: 1324 if (stack.size() < 2) { 1325 if (error_ptr) 1326 error_ptr->SetErrorString( 1327 "Expression stack needs at least 2 items for DW_OP_over."); 1328 return false; 1329 } else 1330 stack.push_back(stack[stack.size() - 2]); 1331 break; 1332 1333 // OPCODE: DW_OP_pick 1334 // OPERANDS: uint8_t index into the current stack 1335 // DESCRIPTION: The stack entry with the specified index (0 through 255, 1336 // inclusive) is pushed on the stack 1337 case DW_OP_pick: { 1338 uint8_t pick_idx = opcodes.GetU8(&offset); 1339 if (pick_idx < stack.size()) 1340 stack.push_back(stack[stack.size() - 1 - pick_idx]); 1341 else { 1342 if (error_ptr) 1343 error_ptr->SetErrorStringWithFormat( 1344 "Index %u out of range for DW_OP_pick.\n", pick_idx); 1345 return false; 1346 } 1347 } break; 1348 1349 // OPCODE: DW_OP_swap 1350 // OPERANDS: none 1351 // DESCRIPTION: swaps the top two stack entries. The entry at the top 1352 // of the stack becomes the second stack entry, and the second entry 1353 // becomes the top of the stack 1354 case DW_OP_swap: 1355 if (stack.size() < 2) { 1356 if (error_ptr) 1357 error_ptr->SetErrorString( 1358 "Expression stack needs at least 2 items for DW_OP_swap."); 1359 return false; 1360 } else { 1361 tmp = stack.back(); 1362 stack.back() = stack[stack.size() - 2]; 1363 stack[stack.size() - 2] = tmp; 1364 } 1365 break; 1366 1367 // OPCODE: DW_OP_rot 1368 // OPERANDS: none 1369 // DESCRIPTION: Rotates the first three stack entries. The entry at 1370 // the top of the stack becomes the third stack entry, the second entry 1371 // becomes the top of the stack, and the third entry becomes the second 1372 // entry. 1373 case DW_OP_rot: 1374 if (stack.size() < 3) { 1375 if (error_ptr) 1376 error_ptr->SetErrorString( 1377 "Expression stack needs at least 3 items for DW_OP_rot."); 1378 return false; 1379 } else { 1380 size_t last_idx = stack.size() - 1; 1381 Value old_top = stack[last_idx]; 1382 stack[last_idx] = stack[last_idx - 1]; 1383 stack[last_idx - 1] = stack[last_idx - 2]; 1384 stack[last_idx - 2] = old_top; 1385 } 1386 break; 1387 1388 // OPCODE: DW_OP_abs 1389 // OPERANDS: none 1390 // DESCRIPTION: pops the top stack entry, interprets it as a signed 1391 // value and pushes its absolute value. If the absolute value can not be 1392 // represented, the result is undefined. 1393 case DW_OP_abs: 1394 if (stack.empty()) { 1395 if (error_ptr) 1396 error_ptr->SetErrorString( 1397 "Expression stack needs at least 1 item for DW_OP_abs."); 1398 return false; 1399 } else if (!stack.back().ResolveValue(exe_ctx).AbsoluteValue()) { 1400 if (error_ptr) 1401 error_ptr->SetErrorString( 1402 "Failed to take the absolute value of the first stack item."); 1403 return false; 1404 } 1405 break; 1406 1407 // OPCODE: DW_OP_and 1408 // OPERANDS: none 1409 // DESCRIPTION: pops the top two stack values, performs a bitwise and 1410 // operation on the two, and pushes the result. 1411 case DW_OP_and: 1412 if (stack.size() < 2) { 1413 if (error_ptr) 1414 error_ptr->SetErrorString( 1415 "Expression stack needs at least 2 items for DW_OP_and."); 1416 return false; 1417 } else { 1418 tmp = stack.back(); 1419 stack.pop_back(); 1420 stack.back().ResolveValue(exe_ctx) = 1421 stack.back().ResolveValue(exe_ctx) & tmp.ResolveValue(exe_ctx); 1422 } 1423 break; 1424 1425 // OPCODE: DW_OP_div 1426 // OPERANDS: none 1427 // DESCRIPTION: pops the top two stack values, divides the former second 1428 // entry by the former top of the stack using signed division, and pushes 1429 // the result. 1430 case DW_OP_div: 1431 if (stack.size() < 2) { 1432 if (error_ptr) 1433 error_ptr->SetErrorString( 1434 "Expression stack needs at least 2 items for DW_OP_div."); 1435 return false; 1436 } else { 1437 tmp = stack.back(); 1438 if (tmp.ResolveValue(exe_ctx).IsZero()) { 1439 if (error_ptr) 1440 error_ptr->SetErrorString("Divide by zero."); 1441 return false; 1442 } else { 1443 stack.pop_back(); 1444 stack.back() = 1445 stack.back().ResolveValue(exe_ctx) / tmp.ResolveValue(exe_ctx); 1446 if (!stack.back().ResolveValue(exe_ctx).IsValid()) { 1447 if (error_ptr) 1448 error_ptr->SetErrorString("Divide failed."); 1449 return false; 1450 } 1451 } 1452 } 1453 break; 1454 1455 // OPCODE: DW_OP_minus 1456 // OPERANDS: none 1457 // DESCRIPTION: pops the top two stack values, subtracts the former top 1458 // of the stack from the former second entry, and pushes the result. 1459 case DW_OP_minus: 1460 if (stack.size() < 2) { 1461 if (error_ptr) 1462 error_ptr->SetErrorString( 1463 "Expression stack needs at least 2 items for DW_OP_minus."); 1464 return false; 1465 } else { 1466 tmp = stack.back(); 1467 stack.pop_back(); 1468 stack.back().ResolveValue(exe_ctx) = 1469 stack.back().ResolveValue(exe_ctx) - tmp.ResolveValue(exe_ctx); 1470 } 1471 break; 1472 1473 // OPCODE: DW_OP_mod 1474 // OPERANDS: none 1475 // DESCRIPTION: pops the top two stack values and pushes the result of 1476 // the calculation: former second stack entry modulo the former top of the 1477 // stack. 1478 case DW_OP_mod: 1479 if (stack.size() < 2) { 1480 if (error_ptr) 1481 error_ptr->SetErrorString( 1482 "Expression stack needs at least 2 items for DW_OP_mod."); 1483 return false; 1484 } else { 1485 tmp = stack.back(); 1486 stack.pop_back(); 1487 stack.back().ResolveValue(exe_ctx) = 1488 stack.back().ResolveValue(exe_ctx) % tmp.ResolveValue(exe_ctx); 1489 } 1490 break; 1491 1492 // OPCODE: DW_OP_mul 1493 // OPERANDS: none 1494 // DESCRIPTION: pops the top two stack entries, multiplies them 1495 // together, and pushes the result. 1496 case DW_OP_mul: 1497 if (stack.size() < 2) { 1498 if (error_ptr) 1499 error_ptr->SetErrorString( 1500 "Expression stack needs at least 2 items for DW_OP_mul."); 1501 return false; 1502 } else { 1503 tmp = stack.back(); 1504 stack.pop_back(); 1505 stack.back().ResolveValue(exe_ctx) = 1506 stack.back().ResolveValue(exe_ctx) * tmp.ResolveValue(exe_ctx); 1507 } 1508 break; 1509 1510 // OPCODE: DW_OP_neg 1511 // OPERANDS: none 1512 // DESCRIPTION: pops the top stack entry, and pushes its negation. 1513 case DW_OP_neg: 1514 if (stack.empty()) { 1515 if (error_ptr) 1516 error_ptr->SetErrorString( 1517 "Expression stack needs at least 1 item for DW_OP_neg."); 1518 return false; 1519 } else { 1520 if (!stack.back().ResolveValue(exe_ctx).UnaryNegate()) { 1521 if (error_ptr) 1522 error_ptr->SetErrorString("Unary negate failed."); 1523 return false; 1524 } 1525 } 1526 break; 1527 1528 // OPCODE: DW_OP_not 1529 // OPERANDS: none 1530 // DESCRIPTION: pops the top stack entry, and pushes its bitwise 1531 // complement 1532 case DW_OP_not: 1533 if (stack.empty()) { 1534 if (error_ptr) 1535 error_ptr->SetErrorString( 1536 "Expression stack needs at least 1 item for DW_OP_not."); 1537 return false; 1538 } else { 1539 if (!stack.back().ResolveValue(exe_ctx).OnesComplement()) { 1540 if (error_ptr) 1541 error_ptr->SetErrorString("Logical NOT failed."); 1542 return false; 1543 } 1544 } 1545 break; 1546 1547 // OPCODE: DW_OP_or 1548 // OPERANDS: none 1549 // DESCRIPTION: pops the top two stack entries, performs a bitwise or 1550 // operation on the two, and pushes the result. 1551 case DW_OP_or: 1552 if (stack.size() < 2) { 1553 if (error_ptr) 1554 error_ptr->SetErrorString( 1555 "Expression stack needs at least 2 items for DW_OP_or."); 1556 return false; 1557 } else { 1558 tmp = stack.back(); 1559 stack.pop_back(); 1560 stack.back().ResolveValue(exe_ctx) = 1561 stack.back().ResolveValue(exe_ctx) | tmp.ResolveValue(exe_ctx); 1562 } 1563 break; 1564 1565 // OPCODE: DW_OP_plus 1566 // OPERANDS: none 1567 // DESCRIPTION: pops the top two stack entries, adds them together, and 1568 // pushes the result. 1569 case DW_OP_plus: 1570 if (stack.size() < 2) { 1571 if (error_ptr) 1572 error_ptr->SetErrorString( 1573 "Expression stack needs at least 2 items for DW_OP_plus."); 1574 return false; 1575 } else { 1576 tmp = stack.back(); 1577 stack.pop_back(); 1578 stack.back().GetScalar() += tmp.GetScalar(); 1579 } 1580 break; 1581 1582 // OPCODE: DW_OP_plus_uconst 1583 // OPERANDS: none 1584 // DESCRIPTION: pops the top stack entry, adds it to the unsigned LEB128 1585 // constant operand and pushes the result. 1586 case DW_OP_plus_uconst: 1587 if (stack.empty()) { 1588 if (error_ptr) 1589 error_ptr->SetErrorString( 1590 "Expression stack needs at least 1 item for DW_OP_plus_uconst."); 1591 return false; 1592 } else { 1593 const uint64_t uconst_value = opcodes.GetULEB128(&offset); 1594 // Implicit conversion from a UINT to a Scalar... 1595 stack.back().GetScalar() += uconst_value; 1596 if (!stack.back().GetScalar().IsValid()) { 1597 if (error_ptr) 1598 error_ptr->SetErrorString("DW_OP_plus_uconst failed."); 1599 return false; 1600 } 1601 } 1602 break; 1603 1604 // OPCODE: DW_OP_shl 1605 // OPERANDS: none 1606 // DESCRIPTION: pops the top two stack entries, shifts the former 1607 // second entry left by the number of bits specified by the former top of 1608 // the stack, and pushes the result. 1609 case DW_OP_shl: 1610 if (stack.size() < 2) { 1611 if (error_ptr) 1612 error_ptr->SetErrorString( 1613 "Expression stack needs at least 2 items for DW_OP_shl."); 1614 return false; 1615 } else { 1616 tmp = stack.back(); 1617 stack.pop_back(); 1618 stack.back().ResolveValue(exe_ctx) <<= tmp.ResolveValue(exe_ctx); 1619 } 1620 break; 1621 1622 // OPCODE: DW_OP_shr 1623 // OPERANDS: none 1624 // DESCRIPTION: pops the top two stack entries, shifts the former second 1625 // entry right logically (filling with zero bits) by the number of bits 1626 // specified by the former top of the stack, and pushes the result. 1627 case DW_OP_shr: 1628 if (stack.size() < 2) { 1629 if (error_ptr) 1630 error_ptr->SetErrorString( 1631 "Expression stack needs at least 2 items for DW_OP_shr."); 1632 return false; 1633 } else { 1634 tmp = stack.back(); 1635 stack.pop_back(); 1636 if (!stack.back().ResolveValue(exe_ctx).ShiftRightLogical( 1637 tmp.ResolveValue(exe_ctx))) { 1638 if (error_ptr) 1639 error_ptr->SetErrorString("DW_OP_shr failed."); 1640 return false; 1641 } 1642 } 1643 break; 1644 1645 // OPCODE: DW_OP_shra 1646 // OPERANDS: none 1647 // DESCRIPTION: pops the top two stack entries, shifts the former second 1648 // entry right arithmetically (divide the magnitude by 2, keep the same 1649 // sign for the result) by the number of bits specified by the former top 1650 // of the stack, and pushes the result. 1651 case DW_OP_shra: 1652 if (stack.size() < 2) { 1653 if (error_ptr) 1654 error_ptr->SetErrorString( 1655 "Expression stack needs at least 2 items for DW_OP_shra."); 1656 return false; 1657 } else { 1658 tmp = stack.back(); 1659 stack.pop_back(); 1660 stack.back().ResolveValue(exe_ctx) >>= tmp.ResolveValue(exe_ctx); 1661 } 1662 break; 1663 1664 // OPCODE: DW_OP_xor 1665 // OPERANDS: none 1666 // DESCRIPTION: pops the top two stack entries, performs the bitwise 1667 // exclusive-or operation on the two, and pushes the result. 1668 case DW_OP_xor: 1669 if (stack.size() < 2) { 1670 if (error_ptr) 1671 error_ptr->SetErrorString( 1672 "Expression stack needs at least 2 items for DW_OP_xor."); 1673 return false; 1674 } else { 1675 tmp = stack.back(); 1676 stack.pop_back(); 1677 stack.back().ResolveValue(exe_ctx) = 1678 stack.back().ResolveValue(exe_ctx) ^ tmp.ResolveValue(exe_ctx); 1679 } 1680 break; 1681 1682 // OPCODE: DW_OP_skip 1683 // OPERANDS: int16_t 1684 // DESCRIPTION: An unconditional branch. Its single operand is a 2-byte 1685 // signed integer constant. The 2-byte constant is the number of bytes of 1686 // the DWARF expression to skip forward or backward from the current 1687 // operation, beginning after the 2-byte constant. 1688 case DW_OP_skip: { 1689 int16_t skip_offset = (int16_t)opcodes.GetU16(&offset); 1690 lldb::offset_t new_offset = offset + skip_offset; 1691 if (opcodes.ValidOffset(new_offset)) 1692 offset = new_offset; 1693 else { 1694 if (error_ptr) 1695 error_ptr->SetErrorString("Invalid opcode offset in DW_OP_skip."); 1696 return false; 1697 } 1698 } break; 1699 1700 // OPCODE: DW_OP_bra 1701 // OPERANDS: int16_t 1702 // DESCRIPTION: A conditional branch. Its single operand is a 2-byte 1703 // signed integer constant. This operation pops the top of stack. If the 1704 // value popped is not the constant 0, the 2-byte constant operand is the 1705 // number of bytes of the DWARF expression to skip forward or backward from 1706 // the current operation, beginning after the 2-byte constant. 1707 case DW_OP_bra: 1708 if (stack.empty()) { 1709 if (error_ptr) 1710 error_ptr->SetErrorString( 1711 "Expression stack needs at least 1 item for DW_OP_bra."); 1712 return false; 1713 } else { 1714 tmp = stack.back(); 1715 stack.pop_back(); 1716 int16_t bra_offset = (int16_t)opcodes.GetU16(&offset); 1717 Scalar zero(0); 1718 if (tmp.ResolveValue(exe_ctx) != zero) { 1719 lldb::offset_t new_offset = offset + bra_offset; 1720 if (opcodes.ValidOffset(new_offset)) 1721 offset = new_offset; 1722 else { 1723 if (error_ptr) 1724 error_ptr->SetErrorString("Invalid opcode offset in DW_OP_bra."); 1725 return false; 1726 } 1727 } 1728 } 1729 break; 1730 1731 // OPCODE: DW_OP_eq 1732 // OPERANDS: none 1733 // DESCRIPTION: pops the top two stack values, compares using the 1734 // equals (==) operator. 1735 // STACK RESULT: push the constant value 1 onto the stack if the result 1736 // of the operation is true or the constant value 0 if the result of the 1737 // operation is false. 1738 case DW_OP_eq: 1739 if (stack.size() < 2) { 1740 if (error_ptr) 1741 error_ptr->SetErrorString( 1742 "Expression stack needs at least 2 items for DW_OP_eq."); 1743 return false; 1744 } else { 1745 tmp = stack.back(); 1746 stack.pop_back(); 1747 stack.back().ResolveValue(exe_ctx) = 1748 stack.back().ResolveValue(exe_ctx) == tmp.ResolveValue(exe_ctx); 1749 } 1750 break; 1751 1752 // OPCODE: DW_OP_ge 1753 // OPERANDS: none 1754 // DESCRIPTION: pops the top two stack values, compares using the 1755 // greater than or equal to (>=) operator. 1756 // STACK RESULT: push the constant value 1 onto the stack if the result 1757 // of the operation is true or the constant value 0 if the result of the 1758 // operation is false. 1759 case DW_OP_ge: 1760 if (stack.size() < 2) { 1761 if (error_ptr) 1762 error_ptr->SetErrorString( 1763 "Expression stack needs at least 2 items for DW_OP_ge."); 1764 return false; 1765 } else { 1766 tmp = stack.back(); 1767 stack.pop_back(); 1768 stack.back().ResolveValue(exe_ctx) = 1769 stack.back().ResolveValue(exe_ctx) >= tmp.ResolveValue(exe_ctx); 1770 } 1771 break; 1772 1773 // OPCODE: DW_OP_gt 1774 // OPERANDS: none 1775 // DESCRIPTION: pops the top two stack values, compares using the 1776 // greater than (>) operator. 1777 // STACK RESULT: push the constant value 1 onto the stack if the result 1778 // of the operation is true or the constant value 0 if the result of the 1779 // operation is false. 1780 case DW_OP_gt: 1781 if (stack.size() < 2) { 1782 if (error_ptr) 1783 error_ptr->SetErrorString( 1784 "Expression stack needs at least 2 items for DW_OP_gt."); 1785 return false; 1786 } else { 1787 tmp = stack.back(); 1788 stack.pop_back(); 1789 stack.back().ResolveValue(exe_ctx) = 1790 stack.back().ResolveValue(exe_ctx) > tmp.ResolveValue(exe_ctx); 1791 } 1792 break; 1793 1794 // OPCODE: DW_OP_le 1795 // OPERANDS: none 1796 // DESCRIPTION: pops the top two stack values, compares using the 1797 // less than or equal to (<=) operator. 1798 // STACK RESULT: push the constant value 1 onto the stack if the result 1799 // of the operation is true or the constant value 0 if the result of the 1800 // operation is false. 1801 case DW_OP_le: 1802 if (stack.size() < 2) { 1803 if (error_ptr) 1804 error_ptr->SetErrorString( 1805 "Expression stack needs at least 2 items for DW_OP_le."); 1806 return false; 1807 } else { 1808 tmp = stack.back(); 1809 stack.pop_back(); 1810 stack.back().ResolveValue(exe_ctx) = 1811 stack.back().ResolveValue(exe_ctx) <= tmp.ResolveValue(exe_ctx); 1812 } 1813 break; 1814 1815 // OPCODE: DW_OP_lt 1816 // OPERANDS: none 1817 // DESCRIPTION: pops the top two stack values, compares using the 1818 // less than (<) operator. 1819 // STACK RESULT: push the constant value 1 onto the stack if the result 1820 // of the operation is true or the constant value 0 if the result of the 1821 // operation is false. 1822 case DW_OP_lt: 1823 if (stack.size() < 2) { 1824 if (error_ptr) 1825 error_ptr->SetErrorString( 1826 "Expression stack needs at least 2 items for DW_OP_lt."); 1827 return false; 1828 } else { 1829 tmp = stack.back(); 1830 stack.pop_back(); 1831 stack.back().ResolveValue(exe_ctx) = 1832 stack.back().ResolveValue(exe_ctx) < tmp.ResolveValue(exe_ctx); 1833 } 1834 break; 1835 1836 // OPCODE: DW_OP_ne 1837 // OPERANDS: none 1838 // DESCRIPTION: pops the top two stack values, compares using the 1839 // not equal (!=) operator. 1840 // STACK RESULT: push the constant value 1 onto the stack if the result 1841 // of the operation is true or the constant value 0 if the result of the 1842 // operation is false. 1843 case DW_OP_ne: 1844 if (stack.size() < 2) { 1845 if (error_ptr) 1846 error_ptr->SetErrorString( 1847 "Expression stack needs at least 2 items for DW_OP_ne."); 1848 return false; 1849 } else { 1850 tmp = stack.back(); 1851 stack.pop_back(); 1852 stack.back().ResolveValue(exe_ctx) = 1853 stack.back().ResolveValue(exe_ctx) != tmp.ResolveValue(exe_ctx); 1854 } 1855 break; 1856 1857 // OPCODE: DW_OP_litn 1858 // OPERANDS: none 1859 // DESCRIPTION: encode the unsigned literal values from 0 through 31. 1860 // STACK RESULT: push the unsigned literal constant value onto the top 1861 // of the stack. 1862 case DW_OP_lit0: 1863 case DW_OP_lit1: 1864 case DW_OP_lit2: 1865 case DW_OP_lit3: 1866 case DW_OP_lit4: 1867 case DW_OP_lit5: 1868 case DW_OP_lit6: 1869 case DW_OP_lit7: 1870 case DW_OP_lit8: 1871 case DW_OP_lit9: 1872 case DW_OP_lit10: 1873 case DW_OP_lit11: 1874 case DW_OP_lit12: 1875 case DW_OP_lit13: 1876 case DW_OP_lit14: 1877 case DW_OP_lit15: 1878 case DW_OP_lit16: 1879 case DW_OP_lit17: 1880 case DW_OP_lit18: 1881 case DW_OP_lit19: 1882 case DW_OP_lit20: 1883 case DW_OP_lit21: 1884 case DW_OP_lit22: 1885 case DW_OP_lit23: 1886 case DW_OP_lit24: 1887 case DW_OP_lit25: 1888 case DW_OP_lit26: 1889 case DW_OP_lit27: 1890 case DW_OP_lit28: 1891 case DW_OP_lit29: 1892 case DW_OP_lit30: 1893 case DW_OP_lit31: 1894 stack.push_back(Scalar((uint64_t)(op - DW_OP_lit0))); 1895 break; 1896 1897 // OPCODE: DW_OP_regN 1898 // OPERANDS: none 1899 // DESCRIPTION: Push the value in register n on the top of the stack. 1900 case DW_OP_reg0: 1901 case DW_OP_reg1: 1902 case DW_OP_reg2: 1903 case DW_OP_reg3: 1904 case DW_OP_reg4: 1905 case DW_OP_reg5: 1906 case DW_OP_reg6: 1907 case DW_OP_reg7: 1908 case DW_OP_reg8: 1909 case DW_OP_reg9: 1910 case DW_OP_reg10: 1911 case DW_OP_reg11: 1912 case DW_OP_reg12: 1913 case DW_OP_reg13: 1914 case DW_OP_reg14: 1915 case DW_OP_reg15: 1916 case DW_OP_reg16: 1917 case DW_OP_reg17: 1918 case DW_OP_reg18: 1919 case DW_OP_reg19: 1920 case DW_OP_reg20: 1921 case DW_OP_reg21: 1922 case DW_OP_reg22: 1923 case DW_OP_reg23: 1924 case DW_OP_reg24: 1925 case DW_OP_reg25: 1926 case DW_OP_reg26: 1927 case DW_OP_reg27: 1928 case DW_OP_reg28: 1929 case DW_OP_reg29: 1930 case DW_OP_reg30: 1931 case DW_OP_reg31: { 1932 reg_num = op - DW_OP_reg0; 1933 1934 if (ReadRegisterValueAsScalar(reg_ctx, reg_kind, reg_num, error_ptr, tmp)) 1935 stack.push_back(tmp); 1936 else 1937 return false; 1938 } break; 1939 // OPCODE: DW_OP_regx 1940 // OPERANDS: 1941 // ULEB128 literal operand that encodes the register. 1942 // DESCRIPTION: Push the value in register on the top of the stack. 1943 case DW_OP_regx: { 1944 reg_num = opcodes.GetULEB128(&offset); 1945 if (ReadRegisterValueAsScalar(reg_ctx, reg_kind, reg_num, error_ptr, tmp)) 1946 stack.push_back(tmp); 1947 else 1948 return false; 1949 } break; 1950 1951 // OPCODE: DW_OP_bregN 1952 // OPERANDS: 1953 // SLEB128 offset from register N 1954 // DESCRIPTION: Value is in memory at the address specified by register 1955 // N plus an offset. 1956 case DW_OP_breg0: 1957 case DW_OP_breg1: 1958 case DW_OP_breg2: 1959 case DW_OP_breg3: 1960 case DW_OP_breg4: 1961 case DW_OP_breg5: 1962 case DW_OP_breg6: 1963 case DW_OP_breg7: 1964 case DW_OP_breg8: 1965 case DW_OP_breg9: 1966 case DW_OP_breg10: 1967 case DW_OP_breg11: 1968 case DW_OP_breg12: 1969 case DW_OP_breg13: 1970 case DW_OP_breg14: 1971 case DW_OP_breg15: 1972 case DW_OP_breg16: 1973 case DW_OP_breg17: 1974 case DW_OP_breg18: 1975 case DW_OP_breg19: 1976 case DW_OP_breg20: 1977 case DW_OP_breg21: 1978 case DW_OP_breg22: 1979 case DW_OP_breg23: 1980 case DW_OP_breg24: 1981 case DW_OP_breg25: 1982 case DW_OP_breg26: 1983 case DW_OP_breg27: 1984 case DW_OP_breg28: 1985 case DW_OP_breg29: 1986 case DW_OP_breg30: 1987 case DW_OP_breg31: { 1988 reg_num = op - DW_OP_breg0; 1989 1990 if (ReadRegisterValueAsScalar(reg_ctx, reg_kind, reg_num, error_ptr, 1991 tmp)) { 1992 int64_t breg_offset = opcodes.GetSLEB128(&offset); 1993 tmp.ResolveValue(exe_ctx) += (uint64_t)breg_offset; 1994 tmp.ClearContext(); 1995 stack.push_back(tmp); 1996 stack.back().SetValueType(Value::eValueTypeLoadAddress); 1997 } else 1998 return false; 1999 } break; 2000 // OPCODE: DW_OP_bregx 2001 // OPERANDS: 2 2002 // ULEB128 literal operand that encodes the register. 2003 // SLEB128 offset from register N 2004 // DESCRIPTION: Value is in memory at the address specified by register 2005 // N plus an offset. 2006 case DW_OP_bregx: { 2007 reg_num = opcodes.GetULEB128(&offset); 2008 2009 if (ReadRegisterValueAsScalar(reg_ctx, reg_kind, reg_num, error_ptr, 2010 tmp)) { 2011 int64_t breg_offset = opcodes.GetSLEB128(&offset); 2012 tmp.ResolveValue(exe_ctx) += (uint64_t)breg_offset; 2013 tmp.ClearContext(); 2014 stack.push_back(tmp); 2015 stack.back().SetValueType(Value::eValueTypeLoadAddress); 2016 } else 2017 return false; 2018 } break; 2019 2020 case DW_OP_fbreg: 2021 if (exe_ctx) { 2022 if (frame) { 2023 Scalar value; 2024 if (frame->GetFrameBaseValue(value, error_ptr)) { 2025 int64_t fbreg_offset = opcodes.GetSLEB128(&offset); 2026 value += fbreg_offset; 2027 stack.push_back(value); 2028 stack.back().SetValueType(Value::eValueTypeLoadAddress); 2029 } else 2030 return false; 2031 } else { 2032 if (error_ptr) 2033 error_ptr->SetErrorString( 2034 "Invalid stack frame in context for DW_OP_fbreg opcode."); 2035 return false; 2036 } 2037 } else { 2038 if (error_ptr) 2039 error_ptr->SetErrorStringWithFormat( 2040 "NULL execution context for DW_OP_fbreg.\n"); 2041 return false; 2042 } 2043 2044 break; 2045 2046 // OPCODE: DW_OP_nop 2047 // OPERANDS: none 2048 // DESCRIPTION: A place holder. It has no effect on the location stack 2049 // or any of its values. 2050 case DW_OP_nop: 2051 break; 2052 2053 // OPCODE: DW_OP_piece 2054 // OPERANDS: 1 2055 // ULEB128: byte size of the piece 2056 // DESCRIPTION: The operand describes the size in bytes of the piece of 2057 // the object referenced by the DWARF expression whose result is at the top 2058 // of the stack. If the piece is located in a register, but does not occupy 2059 // the entire register, the placement of the piece within that register is 2060 // defined by the ABI. 2061 // 2062 // Many compilers store a single variable in sets of registers, or store a 2063 // variable partially in memory and partially in registers. DW_OP_piece 2064 // provides a way of describing how large a part of a variable a particular 2065 // DWARF expression refers to. 2066 case DW_OP_piece: { 2067 const uint64_t piece_byte_size = opcodes.GetULEB128(&offset); 2068 2069 if (piece_byte_size > 0) { 2070 Value curr_piece; 2071 2072 if (stack.empty()) { 2073 // In a multi-piece expression, this means that the current piece is 2074 // not available. Fill with zeros for now by resizing the data and 2075 // appending it 2076 curr_piece.ResizeData(piece_byte_size); 2077 // Note that "0" is not a correct value for the unknown bits. 2078 // It would be better to also return a mask of valid bits together 2079 // with the expression result, so the debugger can print missing 2080 // members as "<optimized out>" or something. 2081 ::memset(curr_piece.GetBuffer().GetBytes(), 0, piece_byte_size); 2082 pieces.AppendDataToHostBuffer(curr_piece); 2083 } else { 2084 Status error; 2085 // Extract the current piece into "curr_piece" 2086 Value curr_piece_source_value(stack.back()); 2087 stack.pop_back(); 2088 2089 const Value::ValueType curr_piece_source_value_type = 2090 curr_piece_source_value.GetValueType(); 2091 switch (curr_piece_source_value_type) { 2092 case Value::eValueTypeLoadAddress: 2093 if (process) { 2094 if (curr_piece.ResizeData(piece_byte_size) == piece_byte_size) { 2095 lldb::addr_t load_addr = 2096 curr_piece_source_value.GetScalar().ULongLong( 2097 LLDB_INVALID_ADDRESS); 2098 if (process->ReadMemory( 2099 load_addr, curr_piece.GetBuffer().GetBytes(), 2100 piece_byte_size, error) != piece_byte_size) { 2101 if (error_ptr) 2102 error_ptr->SetErrorStringWithFormat( 2103 "failed to read memory DW_OP_piece(%" PRIu64 2104 ") from 0x%" PRIx64, 2105 piece_byte_size, load_addr); 2106 return false; 2107 } 2108 } else { 2109 if (error_ptr) 2110 error_ptr->SetErrorStringWithFormat( 2111 "failed to resize the piece memory buffer for " 2112 "DW_OP_piece(%" PRIu64 ")", 2113 piece_byte_size); 2114 return false; 2115 } 2116 } 2117 break; 2118 2119 case Value::eValueTypeFileAddress: 2120 case Value::eValueTypeHostAddress: 2121 if (error_ptr) { 2122 lldb::addr_t addr = curr_piece_source_value.GetScalar().ULongLong( 2123 LLDB_INVALID_ADDRESS); 2124 error_ptr->SetErrorStringWithFormat( 2125 "failed to read memory DW_OP_piece(%" PRIu64 2126 ") from %s address 0x%" PRIx64, 2127 piece_byte_size, curr_piece_source_value.GetValueType() == 2128 Value::eValueTypeFileAddress 2129 ? "file" 2130 : "host", 2131 addr); 2132 } 2133 return false; 2134 2135 case Value::eValueTypeScalar: { 2136 uint32_t bit_size = piece_byte_size * 8; 2137 uint32_t bit_offset = 0; 2138 Scalar &scalar = curr_piece_source_value.GetScalar(); 2139 if (!scalar.ExtractBitfield( 2140 bit_size, bit_offset)) { 2141 if (error_ptr) 2142 error_ptr->SetErrorStringWithFormat( 2143 "unable to extract %" PRIu64 " bytes from a %" PRIu64 2144 " byte scalar value.", 2145 piece_byte_size, 2146 (uint64_t)curr_piece_source_value.GetScalar() 2147 .GetByteSize()); 2148 return false; 2149 } 2150 // Create curr_piece with bit_size. By default Scalar 2151 // grows to the nearest host integer type. 2152 llvm::APInt fail_value(1, 0, false); 2153 llvm::APInt ap_int = scalar.UInt128(fail_value); 2154 assert(ap_int.getBitWidth() >= bit_size); 2155 llvm::ArrayRef<uint64_t> buf{ap_int.getRawData(), 2156 ap_int.getNumWords()}; 2157 curr_piece.GetScalar() = Scalar(llvm::APInt(bit_size, buf)); 2158 } break; 2159 2160 case Value::eValueTypeVector: { 2161 if (curr_piece_source_value.GetVector().length >= piece_byte_size) 2162 curr_piece_source_value.GetVector().length = piece_byte_size; 2163 else { 2164 if (error_ptr) 2165 error_ptr->SetErrorStringWithFormat( 2166 "unable to extract %" PRIu64 " bytes from a %" PRIu64 2167 " byte vector value.", 2168 piece_byte_size, 2169 (uint64_t)curr_piece_source_value.GetVector().length); 2170 return false; 2171 } 2172 } break; 2173 } 2174 2175 // Check if this is the first piece? 2176 if (op_piece_offset == 0) { 2177 // This is the first piece, we should push it back onto the stack 2178 // so subsequent pieces will be able to access this piece and add 2179 // to it. 2180 if (pieces.AppendDataToHostBuffer(curr_piece) == 0) { 2181 if (error_ptr) 2182 error_ptr->SetErrorString("failed to append piece data"); 2183 return false; 2184 } 2185 } else { 2186 // If this is the second or later piece there should be a value on 2187 // the stack. 2188 if (pieces.GetBuffer().GetByteSize() != op_piece_offset) { 2189 if (error_ptr) 2190 error_ptr->SetErrorStringWithFormat( 2191 "DW_OP_piece for offset %" PRIu64 2192 " but top of stack is of size %" PRIu64, 2193 op_piece_offset, pieces.GetBuffer().GetByteSize()); 2194 return false; 2195 } 2196 2197 if (pieces.AppendDataToHostBuffer(curr_piece) == 0) { 2198 if (error_ptr) 2199 error_ptr->SetErrorString("failed to append piece data"); 2200 return false; 2201 } 2202 } 2203 } 2204 op_piece_offset += piece_byte_size; 2205 } 2206 } break; 2207 2208 case DW_OP_bit_piece: // 0x9d ULEB128 bit size, ULEB128 bit offset (DWARF3); 2209 if (stack.size() < 1) { 2210 if (error_ptr) 2211 error_ptr->SetErrorString( 2212 "Expression stack needs at least 1 item for DW_OP_bit_piece."); 2213 return false; 2214 } else { 2215 const uint64_t piece_bit_size = opcodes.GetULEB128(&offset); 2216 const uint64_t piece_bit_offset = opcodes.GetULEB128(&offset); 2217 switch (stack.back().GetValueType()) { 2218 case Value::eValueTypeScalar: { 2219 if (!stack.back().GetScalar().ExtractBitfield(piece_bit_size, 2220 piece_bit_offset)) { 2221 if (error_ptr) 2222 error_ptr->SetErrorStringWithFormat( 2223 "unable to extract %" PRIu64 " bit value with %" PRIu64 2224 " bit offset from a %" PRIu64 " bit scalar value.", 2225 piece_bit_size, piece_bit_offset, 2226 (uint64_t)(stack.back().GetScalar().GetByteSize() * 8)); 2227 return false; 2228 } 2229 } break; 2230 2231 case Value::eValueTypeFileAddress: 2232 case Value::eValueTypeLoadAddress: 2233 case Value::eValueTypeHostAddress: 2234 if (error_ptr) { 2235 error_ptr->SetErrorStringWithFormat( 2236 "unable to extract DW_OP_bit_piece(bit_size = %" PRIu64 2237 ", bit_offset = %" PRIu64 ") from an address value.", 2238 piece_bit_size, piece_bit_offset); 2239 } 2240 return false; 2241 2242 case Value::eValueTypeVector: 2243 if (error_ptr) { 2244 error_ptr->SetErrorStringWithFormat( 2245 "unable to extract DW_OP_bit_piece(bit_size = %" PRIu64 2246 ", bit_offset = %" PRIu64 ") from a vector value.", 2247 piece_bit_size, piece_bit_offset); 2248 } 2249 return false; 2250 } 2251 } 2252 break; 2253 2254 // OPCODE: DW_OP_push_object_address 2255 // OPERANDS: none 2256 // DESCRIPTION: Pushes the address of the object currently being 2257 // evaluated as part of evaluation of a user presented expression. This 2258 // object may correspond to an independent variable described by its own 2259 // DIE or it may be a component of an array, structure, or class whose 2260 // address has been dynamically determined by an earlier step during user 2261 // expression evaluation. 2262 case DW_OP_push_object_address: 2263 if (object_address_ptr) 2264 stack.push_back(*object_address_ptr); 2265 else { 2266 if (error_ptr) 2267 error_ptr->SetErrorString("DW_OP_push_object_address used without " 2268 "specifying an object address"); 2269 return false; 2270 } 2271 break; 2272 2273 // OPCODE: DW_OP_call2 2274 // OPERANDS: 2275 // uint16_t compile unit relative offset of a DIE 2276 // DESCRIPTION: Performs subroutine calls during evaluation 2277 // of a DWARF expression. The operand is the 2-byte unsigned offset of a 2278 // debugging information entry in the current compilation unit. 2279 // 2280 // Operand interpretation is exactly like that for DW_FORM_ref2. 2281 // 2282 // This operation transfers control of DWARF expression evaluation to the 2283 // DW_AT_location attribute of the referenced DIE. If there is no such 2284 // attribute, then there is no effect. Execution of the DWARF expression of 2285 // a DW_AT_location attribute may add to and/or remove from values on the 2286 // stack. Execution returns to the point following the call when the end of 2287 // the attribute is reached. Values on the stack at the time of the call 2288 // may be used as parameters by the called expression and values left on 2289 // the stack by the called expression may be used as return values by prior 2290 // agreement between the calling and called expressions. 2291 case DW_OP_call2: 2292 if (error_ptr) 2293 error_ptr->SetErrorString("Unimplemented opcode DW_OP_call2."); 2294 return false; 2295 // OPCODE: DW_OP_call4 2296 // OPERANDS: 1 2297 // uint32_t compile unit relative offset of a DIE 2298 // DESCRIPTION: Performs a subroutine call during evaluation of a DWARF 2299 // expression. For DW_OP_call4, the operand is a 4-byte unsigned offset of 2300 // a debugging information entry in the current compilation unit. 2301 // 2302 // Operand interpretation DW_OP_call4 is exactly like that for 2303 // DW_FORM_ref4. 2304 // 2305 // This operation transfers control of DWARF expression evaluation to the 2306 // DW_AT_location attribute of the referenced DIE. If there is no such 2307 // attribute, then there is no effect. Execution of the DWARF expression of 2308 // a DW_AT_location attribute may add to and/or remove from values on the 2309 // stack. Execution returns to the point following the call when the end of 2310 // the attribute is reached. Values on the stack at the time of the call 2311 // may be used as parameters by the called expression and values left on 2312 // the stack by the called expression may be used as return values by prior 2313 // agreement between the calling and called expressions. 2314 case DW_OP_call4: 2315 if (error_ptr) 2316 error_ptr->SetErrorString("Unimplemented opcode DW_OP_call4."); 2317 return false; 2318 2319 // OPCODE: DW_OP_stack_value 2320 // OPERANDS: None 2321 // DESCRIPTION: Specifies that the object does not exist in memory but 2322 // rather is a constant value. The value from the top of the stack is the 2323 // value to be used. This is the actual object value and not the location. 2324 case DW_OP_stack_value: 2325 if (stack.empty()) { 2326 if (error_ptr) 2327 error_ptr->SetErrorString( 2328 "Expression stack needs at least 1 item for DW_OP_stack_value."); 2329 return false; 2330 } 2331 stack.back().SetValueType(Value::eValueTypeScalar); 2332 break; 2333 2334 // OPCODE: DW_OP_convert 2335 // OPERANDS: 1 2336 // A ULEB128 that is either a DIE offset of a 2337 // DW_TAG_base_type or 0 for the generic (pointer-sized) type. 2338 // 2339 // DESCRIPTION: Pop the top stack element, convert it to a 2340 // different type, and push the result. 2341 case DW_OP_convert: { 2342 if (stack.size() < 1) { 2343 if (error_ptr) 2344 error_ptr->SetErrorString( 2345 "Expression stack needs at least 1 item for DW_OP_convert."); 2346 return false; 2347 } 2348 const uint64_t die_offset = opcodes.GetULEB128(&offset); 2349 uint64_t bit_size; 2350 bool sign; 2351 if (die_offset == 0) { 2352 // The generic type has the size of an address on the target 2353 // machine and an unspecified signedness. Scalar has no 2354 // "unspecified signedness", so we use unsigned types. 2355 if (!module_sp) { 2356 if (error_ptr) 2357 error_ptr->SetErrorString("No module"); 2358 return false; 2359 } 2360 sign = false; 2361 bit_size = module_sp->GetArchitecture().GetAddressByteSize() * 8; 2362 if (!bit_size) { 2363 if (error_ptr) 2364 error_ptr->SetErrorString("unspecified architecture"); 2365 return false; 2366 } 2367 } else { 2368 // Retrieve the type DIE that the value is being converted to. 2369 // FIXME: the constness has annoying ripple effects. 2370 DWARFDIE die = const_cast<DWARFUnit *>(dwarf_cu)->GetDIE(die_offset); 2371 if (!die) { 2372 if (error_ptr) 2373 error_ptr->SetErrorString("Cannot resolve DW_OP_convert type DIE"); 2374 return false; 2375 } 2376 uint64_t encoding = 2377 die.GetAttributeValueAsUnsigned(DW_AT_encoding, DW_ATE_hi_user); 2378 bit_size = die.GetAttributeValueAsUnsigned(DW_AT_byte_size, 0) * 8; 2379 if (!bit_size) 2380 bit_size = die.GetAttributeValueAsUnsigned(DW_AT_bit_size, 0); 2381 if (!bit_size) { 2382 if (error_ptr) 2383 error_ptr->SetErrorString("Unsupported type size in DW_OP_convert"); 2384 return false; 2385 } 2386 switch (encoding) { 2387 case DW_ATE_signed: 2388 case DW_ATE_signed_char: 2389 sign = true; 2390 break; 2391 case DW_ATE_unsigned: 2392 case DW_ATE_unsigned_char: 2393 sign = false; 2394 break; 2395 default: 2396 if (error_ptr) 2397 error_ptr->SetErrorString("Unsupported encoding in DW_OP_convert"); 2398 return false; 2399 } 2400 } 2401 Scalar &top = stack.back().ResolveValue(exe_ctx); 2402 top.TruncOrExtendTo(bit_size, sign); 2403 break; 2404 } 2405 2406 // OPCODE: DW_OP_call_frame_cfa 2407 // OPERANDS: None 2408 // DESCRIPTION: Specifies a DWARF expression that pushes the value of 2409 // the canonical frame address consistent with the call frame information 2410 // located in .debug_frame (or in the FDEs of the eh_frame section). 2411 case DW_OP_call_frame_cfa: 2412 if (frame) { 2413 // Note that we don't have to parse FDEs because this DWARF expression 2414 // is commonly evaluated with a valid stack frame. 2415 StackID id = frame->GetStackID(); 2416 addr_t cfa = id.GetCallFrameAddress(); 2417 if (cfa != LLDB_INVALID_ADDRESS) { 2418 stack.push_back(Scalar(cfa)); 2419 stack.back().SetValueType(Value::eValueTypeLoadAddress); 2420 } else if (error_ptr) 2421 error_ptr->SetErrorString("Stack frame does not include a canonical " 2422 "frame address for DW_OP_call_frame_cfa " 2423 "opcode."); 2424 } else { 2425 if (error_ptr) 2426 error_ptr->SetErrorString("Invalid stack frame in context for " 2427 "DW_OP_call_frame_cfa opcode."); 2428 return false; 2429 } 2430 break; 2431 2432 // OPCODE: DW_OP_form_tls_address (or the old pre-DWARFv3 vendor extension 2433 // opcode, DW_OP_GNU_push_tls_address) 2434 // OPERANDS: none 2435 // DESCRIPTION: Pops a TLS offset from the stack, converts it to 2436 // an address in the current thread's thread-local storage block, and 2437 // pushes it on the stack. 2438 case DW_OP_form_tls_address: 2439 case DW_OP_GNU_push_tls_address: { 2440 if (stack.size() < 1) { 2441 if (error_ptr) { 2442 if (op == DW_OP_form_tls_address) 2443 error_ptr->SetErrorString( 2444 "DW_OP_form_tls_address needs an argument."); 2445 else 2446 error_ptr->SetErrorString( 2447 "DW_OP_GNU_push_tls_address needs an argument."); 2448 } 2449 return false; 2450 } 2451 2452 if (!exe_ctx || !module_sp) { 2453 if (error_ptr) 2454 error_ptr->SetErrorString("No context to evaluate TLS within."); 2455 return false; 2456 } 2457 2458 Thread *thread = exe_ctx->GetThreadPtr(); 2459 if (!thread) { 2460 if (error_ptr) 2461 error_ptr->SetErrorString("No thread to evaluate TLS within."); 2462 return false; 2463 } 2464 2465 // Lookup the TLS block address for this thread and module. 2466 const addr_t tls_file_addr = 2467 stack.back().GetScalar().ULongLong(LLDB_INVALID_ADDRESS); 2468 const addr_t tls_load_addr = 2469 thread->GetThreadLocalData(module_sp, tls_file_addr); 2470 2471 if (tls_load_addr == LLDB_INVALID_ADDRESS) { 2472 if (error_ptr) 2473 error_ptr->SetErrorString( 2474 "No TLS data currently exists for this thread."); 2475 return false; 2476 } 2477 2478 stack.back().GetScalar() = tls_load_addr; 2479 stack.back().SetValueType(Value::eValueTypeLoadAddress); 2480 } break; 2481 2482 // OPCODE: DW_OP_addrx (DW_OP_GNU_addr_index is the legacy name.) 2483 // OPERANDS: 1 2484 // ULEB128: index to the .debug_addr section 2485 // DESCRIPTION: Pushes an address to the stack from the .debug_addr 2486 // section with the base address specified by the DW_AT_addr_base attribute 2487 // and the 0 based index is the ULEB128 encoded index. 2488 case DW_OP_addrx: 2489 case DW_OP_GNU_addr_index: { 2490 if (!dwarf_cu) { 2491 if (error_ptr) 2492 error_ptr->SetErrorString("DW_OP_GNU_addr_index found without a " 2493 "compile unit being specified"); 2494 return false; 2495 } 2496 uint64_t index = opcodes.GetULEB128(&offset); 2497 lldb::addr_t value = ReadAddressFromDebugAddrSection(dwarf_cu, index); 2498 stack.push_back(Scalar(value)); 2499 stack.back().SetValueType(Value::eValueTypeFileAddress); 2500 } break; 2501 2502 // OPCODE: DW_OP_GNU_const_index 2503 // OPERANDS: 1 2504 // ULEB128: index to the .debug_addr section 2505 // DESCRIPTION: Pushes an constant with the size of a machine address to 2506 // the stack from the .debug_addr section with the base address specified 2507 // by the DW_AT_addr_base attribute and the 0 based index is the ULEB128 2508 // encoded index. 2509 case DW_OP_GNU_const_index: { 2510 if (!dwarf_cu) { 2511 if (error_ptr) 2512 error_ptr->SetErrorString("DW_OP_GNU_const_index found without a " 2513 "compile unit being specified"); 2514 return false; 2515 } 2516 uint64_t index = opcodes.GetULEB128(&offset); 2517 lldb::addr_t value = ReadAddressFromDebugAddrSection(dwarf_cu, index); 2518 stack.push_back(Scalar(value)); 2519 } break; 2520 2521 case DW_OP_GNU_entry_value: 2522 case DW_OP_entry_value: { 2523 if (!Evaluate_DW_OP_entry_value(stack, exe_ctx, reg_ctx, opcodes, offset, 2524 error_ptr, log)) { 2525 LLDB_ERRORF(error_ptr, "Could not evaluate %s.", 2526 DW_OP_value_to_name(op)); 2527 return false; 2528 } 2529 break; 2530 } 2531 2532 default: 2533 if (error_ptr) 2534 error_ptr->SetErrorStringWithFormatv( 2535 "Unhandled opcode {0} in DWARFExpression", LocationAtom(op)); 2536 return false; 2537 } 2538 } 2539 2540 if (stack.empty()) { 2541 // Nothing on the stack, check if we created a piece value from DW_OP_piece 2542 // or DW_OP_bit_piece opcodes 2543 if (pieces.GetBuffer().GetByteSize()) { 2544 result = pieces; 2545 } else { 2546 if (error_ptr) 2547 error_ptr->SetErrorString("Stack empty after evaluation."); 2548 return false; 2549 } 2550 } else { 2551 if (log && log->GetVerbose()) { 2552 size_t count = stack.size(); 2553 LLDB_LOGF(log, "Stack after operation has %" PRIu64 " values:", 2554 (uint64_t)count); 2555 for (size_t i = 0; i < count; ++i) { 2556 StreamString new_value; 2557 new_value.Printf("[%" PRIu64 "]", (uint64_t)i); 2558 stack[i].Dump(&new_value); 2559 LLDB_LOGF(log, " %s", new_value.GetData()); 2560 } 2561 } 2562 result = stack.back(); 2563 } 2564 return true; // Return true on success 2565 } 2566 2567 static DataExtractor ToDataExtractor(const llvm::DWARFLocationExpression &loc, 2568 ByteOrder byte_order, uint32_t addr_size) { 2569 auto buffer_sp = 2570 std::make_shared<DataBufferHeap>(loc.Expr.data(), loc.Expr.size()); 2571 return DataExtractor(buffer_sp, byte_order, addr_size); 2572 } 2573 2574 llvm::Optional<DataExtractor> 2575 DWARFExpression::GetLocationExpression(addr_t load_function_start, 2576 addr_t addr) const { 2577 Log *log = GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS); 2578 2579 std::unique_ptr<llvm::DWARFLocationTable> loctable_up = 2580 m_dwarf_cu->GetLocationTable(m_data); 2581 llvm::Optional<DataExtractor> result; 2582 uint64_t offset = 0; 2583 auto lookup_addr = 2584 [&](uint32_t index) -> llvm::Optional<llvm::object::SectionedAddress> { 2585 addr_t address = ReadAddressFromDebugAddrSection(m_dwarf_cu, index); 2586 if (address == LLDB_INVALID_ADDRESS) 2587 return llvm::None; 2588 return llvm::object::SectionedAddress{address}; 2589 }; 2590 auto process_list = [&](llvm::Expected<llvm::DWARFLocationExpression> loc) { 2591 if (!loc) { 2592 LLDB_LOG_ERROR(log, loc.takeError(), "{0}"); 2593 return true; 2594 } 2595 if (loc->Range) { 2596 // This relocates low_pc and high_pc by adding the difference between the 2597 // function file address, and the actual address it is loaded in memory. 2598 addr_t slide = load_function_start - m_loclist_addresses->func_file_addr; 2599 loc->Range->LowPC += slide; 2600 loc->Range->HighPC += slide; 2601 2602 if (loc->Range->LowPC <= addr && addr < loc->Range->HighPC) 2603 result = ToDataExtractor(*loc, m_data.GetByteOrder(), 2604 m_data.GetAddressByteSize()); 2605 } 2606 return !result; 2607 }; 2608 llvm::Error E = loctable_up->visitAbsoluteLocationList( 2609 offset, llvm::object::SectionedAddress{m_loclist_addresses->cu_file_addr}, 2610 lookup_addr, process_list); 2611 if (E) 2612 LLDB_LOG_ERROR(log, std::move(E), "{0}"); 2613 return result; 2614 } 2615 2616 bool DWARFExpression::MatchesOperand(StackFrame &frame, 2617 const Instruction::Operand &operand) { 2618 using namespace OperandMatchers; 2619 2620 RegisterContextSP reg_ctx_sp = frame.GetRegisterContext(); 2621 if (!reg_ctx_sp) { 2622 return false; 2623 } 2624 2625 DataExtractor opcodes; 2626 if (IsLocationList()) { 2627 SymbolContext sc = frame.GetSymbolContext(eSymbolContextFunction); 2628 if (!sc.function) 2629 return false; 2630 2631 addr_t load_function_start = 2632 sc.function->GetAddressRange().GetBaseAddress().GetFileAddress(); 2633 if (load_function_start == LLDB_INVALID_ADDRESS) 2634 return false; 2635 2636 addr_t pc = frame.GetFrameCodeAddress().GetLoadAddress( 2637 frame.CalculateTarget().get()); 2638 2639 if (llvm::Optional<DataExtractor> expr = GetLocationExpression(load_function_start, pc)) 2640 opcodes = std::move(*expr); 2641 else 2642 return false; 2643 } else 2644 opcodes = m_data; 2645 2646 2647 lldb::offset_t op_offset = 0; 2648 uint8_t opcode = opcodes.GetU8(&op_offset); 2649 2650 if (opcode == DW_OP_fbreg) { 2651 int64_t offset = opcodes.GetSLEB128(&op_offset); 2652 2653 DWARFExpression *fb_expr = frame.GetFrameBaseExpression(nullptr); 2654 if (!fb_expr) { 2655 return false; 2656 } 2657 2658 auto recurse = [&frame, fb_expr](const Instruction::Operand &child) { 2659 return fb_expr->MatchesOperand(frame, child); 2660 }; 2661 2662 if (!offset && 2663 MatchUnaryOp(MatchOpType(Instruction::Operand::Type::Dereference), 2664 recurse)(operand)) { 2665 return true; 2666 } 2667 2668 return MatchUnaryOp( 2669 MatchOpType(Instruction::Operand::Type::Dereference), 2670 MatchBinaryOp(MatchOpType(Instruction::Operand::Type::Sum), 2671 MatchImmOp(offset), recurse))(operand); 2672 } 2673 2674 bool dereference = false; 2675 const RegisterInfo *reg = nullptr; 2676 int64_t offset = 0; 2677 2678 if (opcode >= DW_OP_reg0 && opcode <= DW_OP_reg31) { 2679 reg = reg_ctx_sp->GetRegisterInfo(m_reg_kind, opcode - DW_OP_reg0); 2680 } else if (opcode >= DW_OP_breg0 && opcode <= DW_OP_breg31) { 2681 offset = opcodes.GetSLEB128(&op_offset); 2682 reg = reg_ctx_sp->GetRegisterInfo(m_reg_kind, opcode - DW_OP_breg0); 2683 } else if (opcode == DW_OP_regx) { 2684 uint32_t reg_num = static_cast<uint32_t>(opcodes.GetULEB128(&op_offset)); 2685 reg = reg_ctx_sp->GetRegisterInfo(m_reg_kind, reg_num); 2686 } else if (opcode == DW_OP_bregx) { 2687 uint32_t reg_num = static_cast<uint32_t>(opcodes.GetULEB128(&op_offset)); 2688 offset = opcodes.GetSLEB128(&op_offset); 2689 reg = reg_ctx_sp->GetRegisterInfo(m_reg_kind, reg_num); 2690 } else { 2691 return false; 2692 } 2693 2694 if (!reg) { 2695 return false; 2696 } 2697 2698 if (dereference) { 2699 if (!offset && 2700 MatchUnaryOp(MatchOpType(Instruction::Operand::Type::Dereference), 2701 MatchRegOp(*reg))(operand)) { 2702 return true; 2703 } 2704 2705 return MatchUnaryOp( 2706 MatchOpType(Instruction::Operand::Type::Dereference), 2707 MatchBinaryOp(MatchOpType(Instruction::Operand::Type::Sum), 2708 MatchRegOp(*reg), 2709 MatchImmOp(offset)))(operand); 2710 } else { 2711 return MatchRegOp(*reg)(operand); 2712 } 2713 } 2714 2715