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 <cinttypes> 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/LLDBLog.h" 20 #include "lldb/Utility/Log.h" 21 #include "lldb/Utility/RegisterValue.h" 22 #include "lldb/Utility/Scalar.h" 23 #include "lldb/Utility/StreamString.h" 24 #include "lldb/Utility/VMRange.h" 25 26 #include "lldb/Host/Host.h" 27 #include "lldb/Utility/Endian.h" 28 29 #include "lldb/Symbol/Function.h" 30 31 #include "lldb/Target/ABI.h" 32 #include "lldb/Target/ExecutionContext.h" 33 #include "lldb/Target/Process.h" 34 #include "lldb/Target/RegisterContext.h" 35 #include "lldb/Target/StackFrame.h" 36 #include "lldb/Target/StackID.h" 37 #include "lldb/Target/Target.h" 38 #include "lldb/Target/Thread.h" 39 #include "llvm/DebugInfo/DWARF/DWARFDebugLoc.h" 40 #include "llvm/DebugInfo/DWARF/DWARFExpression.h" 41 42 #include "Plugins/SymbolFile/DWARF/DWARFUnit.h" 43 44 using namespace lldb; 45 using namespace lldb_private; 46 using namespace lldb_private::dwarf; 47 48 static lldb::addr_t 49 ReadAddressFromDebugAddrSection(const DWARFUnit *dwarf_cu, 50 uint32_t index) { 51 uint32_t index_size = dwarf_cu->GetAddressByteSize(); 52 dw_offset_t addr_base = dwarf_cu->GetAddrBase(); 53 lldb::offset_t offset = addr_base + index * index_size; 54 const DWARFDataExtractor &data = 55 dwarf_cu->GetSymbolFileDWARF().GetDWARFContext().getOrLoadAddrData(); 56 if (data.ValidOffsetForDataOfSize(offset, index_size)) 57 return data.GetMaxU64_unchecked(&offset, index_size); 58 return LLDB_INVALID_ADDRESS; 59 } 60 61 // DWARFExpression constructor 62 DWARFExpression::DWARFExpression() : m_module_wp(), m_data() {} 63 64 DWARFExpression::DWARFExpression(lldb::ModuleSP module_sp, 65 const DataExtractor &data, 66 const DWARFUnit *dwarf_cu) 67 : m_module_wp(), m_data(data), m_dwarf_cu(dwarf_cu) { 68 if (module_sp) 69 m_module_wp = module_sp; 70 } 71 72 // Destructor 73 DWARFExpression::~DWARFExpression() = default; 74 75 bool DWARFExpression::IsValid() const { return m_data.GetByteSize() > 0; } 76 77 void DWARFExpression::UpdateValue(uint64_t const_value, 78 lldb::offset_t const_value_byte_size, 79 uint8_t addr_byte_size) { 80 if (!const_value_byte_size) 81 return; 82 83 m_data.SetData( 84 DataBufferSP(new DataBufferHeap(&const_value, const_value_byte_size))); 85 m_data.SetByteOrder(endian::InlHostByteOrder()); 86 m_data.SetAddressByteSize(addr_byte_size); 87 } 88 89 void DWARFExpression::DumpLocation(Stream *s, const DataExtractor &data, 90 lldb::DescriptionLevel level, 91 ABI *abi) const { 92 llvm::DWARFExpression(data.GetAsLLVM(), data.GetAddressByteSize()) 93 .print(s->AsRawOstream(), llvm::DIDumpOptions(), 94 abi ? &abi->GetMCRegisterInfo() : nullptr, nullptr); 95 } 96 97 void DWARFExpression::SetLocationListAddresses(addr_t cu_file_addr, 98 addr_t func_file_addr) { 99 m_loclist_addresses = LoclistAddresses{cu_file_addr, func_file_addr}; 100 } 101 102 int DWARFExpression::GetRegisterKind() { return m_reg_kind; } 103 104 void DWARFExpression::SetRegisterKind(RegisterKind reg_kind) { 105 m_reg_kind = reg_kind; 106 } 107 108 bool DWARFExpression::IsLocationList() const { 109 return bool(m_loclist_addresses); 110 } 111 112 namespace { 113 /// Implement enough of the DWARFObject interface in order to be able to call 114 /// DWARFLocationTable::dumpLocationList. We don't have access to a real 115 /// DWARFObject here because DWARFExpression is used in non-DWARF scenarios too. 116 class DummyDWARFObject final: public llvm::DWARFObject { 117 public: 118 DummyDWARFObject(bool IsLittleEndian) : IsLittleEndian(IsLittleEndian) {} 119 120 bool isLittleEndian() const override { return IsLittleEndian; } 121 122 llvm::Optional<llvm::RelocAddrEntry> find(const llvm::DWARFSection &Sec, 123 uint64_t Pos) const override { 124 return llvm::None; 125 } 126 private: 127 bool IsLittleEndian; 128 }; 129 } 130 131 void DWARFExpression::GetDescription(Stream *s, lldb::DescriptionLevel level, 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->SetErrorString("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::ValueType::Scalar); 178 value.SetContext(Value::ContextType::RegisterInfo, 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 // Make en encoder that contains a copy of the location expression data 466 // so we can write the address into the buffer using the correct byte 467 // order. 468 DataEncoder encoder(m_data.GetDataStart(), m_data.GetByteSize(), 469 m_data.GetByteOrder(), addr_byte_size); 470 471 // Replace the address in the new buffer 472 if (encoder.PutAddress(offset, file_addr) == UINT32_MAX) 473 return false; 474 475 // All went well, so now we can reset the data using a shared pointer to 476 // the heap data so "m_data" will now correctly manage the heap data. 477 m_data.SetData(encoder.GetDataBuffer()); 478 return true; 479 } else { 480 const offset_t op_arg_size = GetOpcodeDataSize(m_data, offset, op); 481 if (op_arg_size == LLDB_INVALID_OFFSET) 482 break; 483 offset += op_arg_size; 484 } 485 } 486 return false; 487 } 488 489 bool DWARFExpression::ContainsThreadLocalStorage() const { 490 // We are assuming for now that any thread local variable will not have a 491 // location list. This has been true for all thread local variables we have 492 // seen so far produced by any compiler. 493 if (IsLocationList()) 494 return false; 495 lldb::offset_t offset = 0; 496 while (m_data.ValidOffset(offset)) { 497 const uint8_t op = m_data.GetU8(&offset); 498 499 if (op == DW_OP_form_tls_address || op == DW_OP_GNU_push_tls_address) 500 return true; 501 const offset_t op_arg_size = GetOpcodeDataSize(m_data, offset, op); 502 if (op_arg_size == LLDB_INVALID_OFFSET) 503 return false; 504 else 505 offset += op_arg_size; 506 } 507 return false; 508 } 509 bool DWARFExpression::LinkThreadLocalStorage( 510 lldb::ModuleSP new_module_sp, 511 std::function<lldb::addr_t(lldb::addr_t file_addr)> const 512 &link_address_callback) { 513 // We are assuming for now that any thread local variable will not have a 514 // location list. This has been true for all thread local variables we have 515 // seen so far produced by any compiler. 516 if (IsLocationList()) 517 return false; 518 519 const uint32_t addr_byte_size = m_data.GetAddressByteSize(); 520 // We have to make a copy of the data as we don't know if this data is from a 521 // read only memory mapped buffer, so we duplicate all of the data first, 522 // then modify it, and if all goes well, we then replace the data for this 523 // expression. 524 525 // Make en encoder that contains a copy of the location expression data so we 526 // can write the address into the buffer using the correct byte order. 527 DataEncoder encoder(m_data.GetDataStart(), m_data.GetByteSize(), 528 m_data.GetByteOrder(), addr_byte_size); 529 530 lldb::offset_t offset = 0; 531 lldb::offset_t const_offset = 0; 532 lldb::addr_t const_value = 0; 533 size_t const_byte_size = 0; 534 while (m_data.ValidOffset(offset)) { 535 const uint8_t op = m_data.GetU8(&offset); 536 537 bool decoded_data = false; 538 switch (op) { 539 case DW_OP_const4u: 540 // Remember the const offset in case we later have a 541 // DW_OP_form_tls_address or DW_OP_GNU_push_tls_address 542 const_offset = offset; 543 const_value = m_data.GetU32(&offset); 544 decoded_data = true; 545 const_byte_size = 4; 546 break; 547 548 case DW_OP_const8u: 549 // Remember the const offset in case we later have a 550 // DW_OP_form_tls_address or DW_OP_GNU_push_tls_address 551 const_offset = offset; 552 const_value = m_data.GetU64(&offset); 553 decoded_data = true; 554 const_byte_size = 8; 555 break; 556 557 case DW_OP_form_tls_address: 558 case DW_OP_GNU_push_tls_address: 559 // DW_OP_form_tls_address and DW_OP_GNU_push_tls_address must be preceded 560 // by a file address on the stack. We assume that DW_OP_const4u or 561 // DW_OP_const8u is used for these values, and we check that the last 562 // opcode we got before either of these was DW_OP_const4u or 563 // DW_OP_const8u. If so, then we can link the value accodingly. For 564 // Darwin, the value in the DW_OP_const4u or DW_OP_const8u is the file 565 // address of a structure that contains a function pointer, the pthread 566 // key and the offset into the data pointed to by the pthread key. So we 567 // must link this address and also set the module of this expression to 568 // the new_module_sp so we can resolve the file address correctly 569 if (const_byte_size > 0) { 570 lldb::addr_t linked_file_addr = link_address_callback(const_value); 571 if (linked_file_addr == LLDB_INVALID_ADDRESS) 572 return false; 573 // Replace the address in the new buffer 574 if (encoder.PutUnsigned(const_offset, const_byte_size, 575 linked_file_addr) == UINT32_MAX) 576 return false; 577 } 578 break; 579 580 default: 581 const_offset = 0; 582 const_value = 0; 583 const_byte_size = 0; 584 break; 585 } 586 587 if (!decoded_data) { 588 const offset_t op_arg_size = GetOpcodeDataSize(m_data, offset, op); 589 if (op_arg_size == LLDB_INVALID_OFFSET) 590 return false; 591 else 592 offset += op_arg_size; 593 } 594 } 595 596 // If we linked the TLS address correctly, update the module so that when the 597 // expression is evaluated it can resolve the file address to a load address 598 // and read the 599 // TLS data 600 m_module_wp = new_module_sp; 601 m_data.SetData(encoder.GetDataBuffer()); 602 return true; 603 } 604 605 bool DWARFExpression::LocationListContainsAddress(addr_t func_load_addr, 606 lldb::addr_t addr) const { 607 if (func_load_addr == LLDB_INVALID_ADDRESS || addr == LLDB_INVALID_ADDRESS) 608 return false; 609 610 if (!IsLocationList()) 611 return false; 612 613 return GetLocationExpression(func_load_addr, addr) != llvm::None; 614 } 615 616 bool DWARFExpression::DumpLocationForAddress(Stream *s, 617 lldb::DescriptionLevel level, 618 addr_t func_load_addr, 619 addr_t address, ABI *abi) { 620 if (!IsLocationList()) { 621 DumpLocation(s, m_data, level, abi); 622 return true; 623 } 624 if (llvm::Optional<DataExtractor> expr = 625 GetLocationExpression(func_load_addr, address)) { 626 DumpLocation(s, *expr, level, abi); 627 return true; 628 } 629 return false; 630 } 631 632 static bool Evaluate_DW_OP_entry_value(std::vector<Value> &stack, 633 ExecutionContext *exe_ctx, 634 RegisterContext *reg_ctx, 635 const DataExtractor &opcodes, 636 lldb::offset_t &opcode_offset, 637 Status *error_ptr, Log *log) { 638 // DW_OP_entry_value(sub-expr) describes the location a variable had upon 639 // function entry: this variable location is presumed to be optimized out at 640 // the current PC value. The caller of the function may have call site 641 // information that describes an alternate location for the variable (e.g. a 642 // constant literal, or a spilled stack value) in the parent frame. 643 // 644 // Example (this is pseudo-code & pseudo-DWARF, but hopefully illustrative): 645 // 646 // void child(int &sink, int x) { 647 // ... 648 // /* "x" gets optimized out. */ 649 // 650 // /* The location of "x" here is: DW_OP_entry_value($reg2). */ 651 // ++sink; 652 // } 653 // 654 // void parent() { 655 // int sink; 656 // 657 // /* 658 // * The callsite information emitted here is: 659 // * 660 // * DW_TAG_call_site 661 // * DW_AT_return_pc ... (for "child(sink, 123);") 662 // * DW_TAG_call_site_parameter (for "sink") 663 // * DW_AT_location ($reg1) 664 // * DW_AT_call_value ($SP - 8) 665 // * DW_TAG_call_site_parameter (for "x") 666 // * DW_AT_location ($reg2) 667 // * DW_AT_call_value ($literal 123) 668 // * 669 // * DW_TAG_call_site 670 // * DW_AT_return_pc ... (for "child(sink, 456);") 671 // * ... 672 // */ 673 // child(sink, 123); 674 // child(sink, 456); 675 // } 676 // 677 // When the program stops at "++sink" within `child`, the debugger determines 678 // the call site by analyzing the return address. Once the call site is found, 679 // the debugger determines which parameter is referenced by DW_OP_entry_value 680 // and evaluates the corresponding location for that parameter in `parent`. 681 682 // 1. Find the function which pushed the current frame onto the stack. 683 if ((!exe_ctx || !exe_ctx->HasTargetScope()) || !reg_ctx) { 684 LLDB_LOG(log, "Evaluate_DW_OP_entry_value: no exe/reg context"); 685 return false; 686 } 687 688 StackFrame *current_frame = exe_ctx->GetFramePtr(); 689 Thread *thread = exe_ctx->GetThreadPtr(); 690 if (!current_frame || !thread) { 691 LLDB_LOG(log, "Evaluate_DW_OP_entry_value: no current frame/thread"); 692 return false; 693 } 694 695 Target &target = exe_ctx->GetTargetRef(); 696 StackFrameSP parent_frame = nullptr; 697 addr_t return_pc = LLDB_INVALID_ADDRESS; 698 uint32_t current_frame_idx = current_frame->GetFrameIndex(); 699 uint32_t num_frames = thread->GetStackFrameCount(); 700 for (uint32_t parent_frame_idx = current_frame_idx + 1; 701 parent_frame_idx < num_frames; ++parent_frame_idx) { 702 parent_frame = thread->GetStackFrameAtIndex(parent_frame_idx); 703 // Require a valid sequence of frames. 704 if (!parent_frame) 705 break; 706 707 // Record the first valid return address, even if this is an inlined frame, 708 // in order to look up the associated call edge in the first non-inlined 709 // parent frame. 710 if (return_pc == LLDB_INVALID_ADDRESS) { 711 return_pc = parent_frame->GetFrameCodeAddress().GetLoadAddress(&target); 712 LLDB_LOG(log, 713 "Evaluate_DW_OP_entry_value: immediate ancestor with pc = {0:x}", 714 return_pc); 715 } 716 717 // If we've found an inlined frame, skip it (these have no call site 718 // parameters). 719 if (parent_frame->IsInlined()) 720 continue; 721 722 // We've found the first non-inlined parent frame. 723 break; 724 } 725 if (!parent_frame || !parent_frame->GetRegisterContext()) { 726 LLDB_LOG(log, "Evaluate_DW_OP_entry_value: no parent frame with reg ctx"); 727 return false; 728 } 729 730 Function *parent_func = 731 parent_frame->GetSymbolContext(eSymbolContextFunction).function; 732 if (!parent_func) { 733 LLDB_LOG(log, "Evaluate_DW_OP_entry_value: no parent function"); 734 return false; 735 } 736 737 // 2. Find the call edge in the parent function responsible for creating the 738 // current activation. 739 Function *current_func = 740 current_frame->GetSymbolContext(eSymbolContextFunction).function; 741 if (!current_func) { 742 LLDB_LOG(log, "Evaluate_DW_OP_entry_value: no current function"); 743 return false; 744 } 745 746 CallEdge *call_edge = nullptr; 747 ModuleList &modlist = target.GetImages(); 748 ExecutionContext parent_exe_ctx = *exe_ctx; 749 parent_exe_ctx.SetFrameSP(parent_frame); 750 if (!parent_frame->IsArtificial()) { 751 // If the parent frame is not artificial, the current activation may be 752 // produced by an ambiguous tail call. In this case, refuse to proceed. 753 call_edge = parent_func->GetCallEdgeForReturnAddress(return_pc, target); 754 if (!call_edge) { 755 LLDB_LOG(log, 756 "Evaluate_DW_OP_entry_value: no call edge for retn-pc = {0:x} " 757 "in parent frame {1}", 758 return_pc, parent_func->GetName()); 759 return false; 760 } 761 Function *callee_func = call_edge->GetCallee(modlist, parent_exe_ctx); 762 if (callee_func != current_func) { 763 LLDB_LOG(log, "Evaluate_DW_OP_entry_value: ambiguous call sequence, " 764 "can't find real parent frame"); 765 return false; 766 } 767 } else { 768 // The StackFrameList solver machinery has deduced that an unambiguous tail 769 // call sequence that produced the current activation. The first edge in 770 // the parent that points to the current function must be valid. 771 for (auto &edge : parent_func->GetTailCallingEdges()) { 772 if (edge->GetCallee(modlist, parent_exe_ctx) == current_func) { 773 call_edge = edge.get(); 774 break; 775 } 776 } 777 } 778 if (!call_edge) { 779 LLDB_LOG(log, "Evaluate_DW_OP_entry_value: no unambiguous edge from parent " 780 "to current function"); 781 return false; 782 } 783 784 // 3. Attempt to locate the DW_OP_entry_value expression in the set of 785 // available call site parameters. If found, evaluate the corresponding 786 // parameter in the context of the parent frame. 787 const uint32_t subexpr_len = opcodes.GetULEB128(&opcode_offset); 788 const void *subexpr_data = opcodes.GetData(&opcode_offset, subexpr_len); 789 if (!subexpr_data) { 790 LLDB_LOG(log, "Evaluate_DW_OP_entry_value: subexpr could not be read"); 791 return false; 792 } 793 794 const CallSiteParameter *matched_param = nullptr; 795 for (const CallSiteParameter ¶m : call_edge->GetCallSiteParameters()) { 796 DataExtractor param_subexpr_extractor; 797 if (!param.LocationInCallee.GetExpressionData(param_subexpr_extractor)) 798 continue; 799 lldb::offset_t param_subexpr_offset = 0; 800 const void *param_subexpr_data = 801 param_subexpr_extractor.GetData(¶m_subexpr_offset, subexpr_len); 802 if (!param_subexpr_data || 803 param_subexpr_extractor.BytesLeft(param_subexpr_offset) != 0) 804 continue; 805 806 // At this point, the DW_OP_entry_value sub-expression and the callee-side 807 // expression in the call site parameter are known to have the same length. 808 // Check whether they are equal. 809 // 810 // Note that an equality check is sufficient: the contents of the 811 // DW_OP_entry_value subexpression are only used to identify the right call 812 // site parameter in the parent, and do not require any special handling. 813 if (memcmp(subexpr_data, param_subexpr_data, subexpr_len) == 0) { 814 matched_param = ¶m; 815 break; 816 } 817 } 818 if (!matched_param) { 819 LLDB_LOG(log, 820 "Evaluate_DW_OP_entry_value: no matching call site param found"); 821 return false; 822 } 823 824 // TODO: Add support for DW_OP_push_object_address within a DW_OP_entry_value 825 // subexpresion whenever llvm does. 826 Value result; 827 const DWARFExpression ¶m_expr = matched_param->LocationInCaller; 828 if (!param_expr.Evaluate(&parent_exe_ctx, 829 parent_frame->GetRegisterContext().get(), 830 /*loclist_base_load_addr=*/LLDB_INVALID_ADDRESS, 831 /*initial_value_ptr=*/nullptr, 832 /*object_address_ptr=*/nullptr, result, error_ptr)) { 833 LLDB_LOG(log, 834 "Evaluate_DW_OP_entry_value: call site param evaluation failed"); 835 return false; 836 } 837 838 stack.push_back(result); 839 return true; 840 } 841 842 bool DWARFExpression::Evaluate(ExecutionContextScope *exe_scope, 843 lldb::addr_t loclist_base_load_addr, 844 const Value *initial_value_ptr, 845 const Value *object_address_ptr, Value &result, 846 Status *error_ptr) const { 847 ExecutionContext exe_ctx(exe_scope); 848 return Evaluate(&exe_ctx, nullptr, loclist_base_load_addr, initial_value_ptr, 849 object_address_ptr, result, error_ptr); 850 } 851 852 bool DWARFExpression::Evaluate(ExecutionContext *exe_ctx, 853 RegisterContext *reg_ctx, 854 lldb::addr_t func_load_addr, 855 const Value *initial_value_ptr, 856 const Value *object_address_ptr, Value &result, 857 Status *error_ptr) const { 858 ModuleSP module_sp = m_module_wp.lock(); 859 860 if (IsLocationList()) { 861 Address pc; 862 StackFrame *frame = nullptr; 863 if (!reg_ctx || !reg_ctx->GetPCForSymbolication(pc)) { 864 frame = exe_ctx->GetFramePtr(); 865 if (!frame) 866 return false; 867 RegisterContextSP reg_ctx_sp = frame->GetRegisterContext(); 868 if (!reg_ctx_sp) 869 return false; 870 reg_ctx_sp->GetPCForSymbolication(pc); 871 } 872 873 if (func_load_addr != LLDB_INVALID_ADDRESS) { 874 if (!pc.IsValid()) { 875 if (error_ptr) 876 error_ptr->SetErrorString("Invalid PC in frame."); 877 return false; 878 } 879 880 Target *target = exe_ctx->GetTargetPtr(); 881 if (llvm::Optional<DataExtractor> expr = GetLocationExpression( 882 func_load_addr, pc.GetLoadAddress(target))) { 883 return DWARFExpression::Evaluate( 884 exe_ctx, reg_ctx, module_sp, *expr, m_dwarf_cu, m_reg_kind, 885 initial_value_ptr, object_address_ptr, result, error_ptr); 886 } 887 } 888 if (error_ptr) 889 error_ptr->SetErrorString("variable not available"); 890 return false; 891 } 892 893 // Not a location list, just a single expression. 894 return DWARFExpression::Evaluate(exe_ctx, reg_ctx, module_sp, m_data, 895 m_dwarf_cu, m_reg_kind, initial_value_ptr, 896 object_address_ptr, result, error_ptr); 897 } 898 899 namespace { 900 /// The location description kinds described by the DWARF v5 901 /// specification. Composite locations are handled out-of-band and 902 /// thus aren't part of the enum. 903 enum LocationDescriptionKind { 904 Empty, 905 Memory, 906 Register, 907 Implicit 908 /* Composite*/ 909 }; 910 /// Adjust value's ValueType according to the kind of location description. 911 void UpdateValueTypeFromLocationDescription(Log *log, const DWARFUnit *dwarf_cu, 912 LocationDescriptionKind kind, 913 Value *value = nullptr) { 914 // Note that this function is conflating DWARF expressions with 915 // DWARF location descriptions. Perhaps it would be better to define 916 // a wrapper for DWARFExpresssion::Eval() that deals with DWARF 917 // location descriptions (which consist of one or more DWARF 918 // expressions). But doing this would mean we'd also need factor the 919 // handling of DW_OP_(bit_)piece out of this function. 920 if (dwarf_cu && dwarf_cu->GetVersion() >= 4) { 921 const char *log_msg = "DWARF location description kind: %s"; 922 switch (kind) { 923 case Empty: 924 LLDB_LOGF(log, log_msg, "Empty"); 925 break; 926 case Memory: 927 LLDB_LOGF(log, log_msg, "Memory"); 928 if (value->GetValueType() == Value::ValueType::Scalar) 929 value->SetValueType(Value::ValueType::LoadAddress); 930 break; 931 case Register: 932 LLDB_LOGF(log, log_msg, "Register"); 933 value->SetValueType(Value::ValueType::Scalar); 934 break; 935 case Implicit: 936 LLDB_LOGF(log, log_msg, "Implicit"); 937 if (value->GetValueType() == Value::ValueType::LoadAddress) 938 value->SetValueType(Value::ValueType::Scalar); 939 break; 940 } 941 } 942 } 943 } // namespace 944 945 /// Helper function to move common code used to resolve a file address and turn 946 /// into a load address. 947 /// 948 /// \param exe_ctx Pointer to the execution context 949 /// \param module_sp shared_ptr contains the module if we have one 950 /// \param error_ptr pointer to Status object if we have one 951 /// \param dw_op_type C-style string used to vary the error output 952 /// \param file_addr the file address we are trying to resolve and turn into a 953 /// load address 954 /// \param so_addr out parameter, will be set to load addresss or section offset 955 /// \param check_sectionoffset bool which determines if having a section offset 956 /// but not a load address is considerd a success 957 /// \returns llvm::Optional containing the load address if resolving and getting 958 /// the load address succeed or an empty Optinal otherwise. If 959 /// check_sectionoffset is true we consider LLDB_INVALID_ADDRESS a 960 /// success if so_addr.IsSectionOffset() is true. 961 static llvm::Optional<lldb::addr_t> 962 ResolveLoadAddress(ExecutionContext *exe_ctx, lldb::ModuleSP &module_sp, 963 Status *error_ptr, const char *dw_op_type, 964 lldb::addr_t file_addr, Address &so_addr, 965 bool check_sectionoffset = false) { 966 if (!module_sp) { 967 if (error_ptr) 968 error_ptr->SetErrorStringWithFormat( 969 "need module to resolve file address for %s", dw_op_type); 970 return {}; 971 } 972 973 if (!module_sp->ResolveFileAddress(file_addr, so_addr)) { 974 if (error_ptr) 975 error_ptr->SetErrorString("failed to resolve file address in module"); 976 return {}; 977 } 978 979 addr_t load_addr = so_addr.GetLoadAddress(exe_ctx->GetTargetPtr()); 980 981 if (load_addr == LLDB_INVALID_ADDRESS && 982 (check_sectionoffset && !so_addr.IsSectionOffset())) { 983 if (error_ptr) 984 error_ptr->SetErrorString("failed to resolve load address"); 985 return {}; 986 } 987 988 return load_addr; 989 } 990 991 /// Helper function to move common code used to load sized data from a uint8_t 992 /// buffer. 993 /// 994 /// \param addr_bytes uint8_t buffer containg raw data 995 /// \param size_addr_bytes how large is the underlying raw data 996 /// \param byte_order what is the byter order of the underlyig data 997 /// \param size How much of the underlying data we want to use 998 /// \return The underlying data converted into a Scalar 999 static Scalar DerefSizeExtractDataHelper(uint8_t *addr_bytes, 1000 size_t size_addr_bytes, 1001 ByteOrder byte_order, size_t size) { 1002 DataExtractor addr_data(addr_bytes, size_addr_bytes, byte_order, size); 1003 1004 lldb::offset_t addr_data_offset = 0; 1005 if (size <= 8) 1006 return addr_data.GetMaxU64(&addr_data_offset, size); 1007 else 1008 return addr_data.GetAddress(&addr_data_offset); 1009 } 1010 1011 bool DWARFExpression::Evaluate( 1012 ExecutionContext *exe_ctx, RegisterContext *reg_ctx, 1013 lldb::ModuleSP module_sp, const DataExtractor &opcodes, 1014 const DWARFUnit *dwarf_cu, const lldb::RegisterKind reg_kind, 1015 const Value *initial_value_ptr, const Value *object_address_ptr, 1016 Value &result, Status *error_ptr) { 1017 1018 if (opcodes.GetByteSize() == 0) { 1019 if (error_ptr) 1020 error_ptr->SetErrorString( 1021 "no location, value may have been optimized out"); 1022 return false; 1023 } 1024 std::vector<Value> stack; 1025 1026 Process *process = nullptr; 1027 StackFrame *frame = nullptr; 1028 1029 if (exe_ctx) { 1030 process = exe_ctx->GetProcessPtr(); 1031 frame = exe_ctx->GetFramePtr(); 1032 } 1033 if (reg_ctx == nullptr && frame) 1034 reg_ctx = frame->GetRegisterContext().get(); 1035 1036 if (initial_value_ptr) 1037 stack.push_back(*initial_value_ptr); 1038 1039 lldb::offset_t offset = 0; 1040 Value tmp; 1041 uint32_t reg_num; 1042 1043 /// Insertion point for evaluating multi-piece expression. 1044 uint64_t op_piece_offset = 0; 1045 Value pieces; // Used for DW_OP_piece 1046 1047 Log *log = GetLog(LLDBLog::Expressions); 1048 // A generic type is "an integral type that has the size of an address and an 1049 // unspecified signedness". For now, just use the signedness of the operand. 1050 // TODO: Implement a real typed stack, and store the genericness of the value 1051 // there. 1052 auto to_generic = [&](auto v) { 1053 bool is_signed = std::is_signed<decltype(v)>::value; 1054 return Scalar(llvm::APSInt( 1055 llvm::APInt(8 * opcodes.GetAddressByteSize(), v, is_signed), 1056 !is_signed)); 1057 }; 1058 1059 // The default kind is a memory location. This is updated by any 1060 // operation that changes this, such as DW_OP_stack_value, and reset 1061 // by composition operations like DW_OP_piece. 1062 LocationDescriptionKind dwarf4_location_description_kind = Memory; 1063 1064 while (opcodes.ValidOffset(offset)) { 1065 const lldb::offset_t op_offset = offset; 1066 const uint8_t op = opcodes.GetU8(&offset); 1067 1068 if (log && log->GetVerbose()) { 1069 size_t count = stack.size(); 1070 LLDB_LOGF(log, "Stack before operation has %" PRIu64 " values:", 1071 (uint64_t)count); 1072 for (size_t i = 0; i < count; ++i) { 1073 StreamString new_value; 1074 new_value.Printf("[%" PRIu64 "]", (uint64_t)i); 1075 stack[i].Dump(&new_value); 1076 LLDB_LOGF(log, " %s", new_value.GetData()); 1077 } 1078 LLDB_LOGF(log, "0x%8.8" PRIx64 ": %s", op_offset, 1079 DW_OP_value_to_name(op)); 1080 } 1081 1082 switch (op) { 1083 // The DW_OP_addr operation has a single operand that encodes a machine 1084 // address and whose size is the size of an address on the target machine. 1085 case DW_OP_addr: 1086 stack.push_back(Scalar(opcodes.GetAddress(&offset))); 1087 stack.back().SetValueType(Value::ValueType::FileAddress); 1088 // Convert the file address to a load address, so subsequent 1089 // DWARF operators can operate on it. 1090 if (frame) 1091 stack.back().ConvertToLoadAddress(module_sp.get(), 1092 frame->CalculateTarget().get()); 1093 break; 1094 1095 // The DW_OP_addr_sect_offset4 is used for any location expressions in 1096 // shared libraries that have a location like: 1097 // DW_OP_addr(0x1000) 1098 // If this address resides in a shared library, then this virtual address 1099 // won't make sense when it is evaluated in the context of a running 1100 // process where shared libraries have been slid. To account for this, this 1101 // new address type where we can store the section pointer and a 4 byte 1102 // offset. 1103 // case DW_OP_addr_sect_offset4: 1104 // { 1105 // result_type = eResultTypeFileAddress; 1106 // lldb::Section *sect = (lldb::Section 1107 // *)opcodes.GetMaxU64(&offset, sizeof(void *)); 1108 // lldb::addr_t sect_offset = opcodes.GetU32(&offset); 1109 // 1110 // Address so_addr (sect, sect_offset); 1111 // lldb::addr_t load_addr = so_addr.GetLoadAddress(); 1112 // if (load_addr != LLDB_INVALID_ADDRESS) 1113 // { 1114 // // We successfully resolve a file address to a load 1115 // // address. 1116 // stack.push_back(load_addr); 1117 // break; 1118 // } 1119 // else 1120 // { 1121 // // We were able 1122 // if (error_ptr) 1123 // error_ptr->SetErrorStringWithFormat ("Section %s in 1124 // %s is not currently loaded.\n", 1125 // sect->GetName().AsCString(), 1126 // sect->GetModule()->GetFileSpec().GetFilename().AsCString()); 1127 // return false; 1128 // } 1129 // } 1130 // break; 1131 1132 // OPCODE: DW_OP_deref 1133 // OPERANDS: none 1134 // DESCRIPTION: Pops the top stack entry and treats it as an address. 1135 // The value retrieved from that address is pushed. The size of the data 1136 // retrieved from the dereferenced address is the size of an address on the 1137 // target machine. 1138 case DW_OP_deref: { 1139 if (stack.empty()) { 1140 if (error_ptr) 1141 error_ptr->SetErrorString("Expression stack empty for DW_OP_deref."); 1142 return false; 1143 } 1144 Value::ValueType value_type = stack.back().GetValueType(); 1145 switch (value_type) { 1146 case Value::ValueType::HostAddress: { 1147 void *src = (void *)stack.back().GetScalar().ULongLong(); 1148 intptr_t ptr; 1149 ::memcpy(&ptr, src, sizeof(void *)); 1150 stack.back().GetScalar() = ptr; 1151 stack.back().ClearContext(); 1152 } break; 1153 case Value::ValueType::FileAddress: { 1154 auto file_addr = stack.back().GetScalar().ULongLong( 1155 LLDB_INVALID_ADDRESS); 1156 1157 Address so_addr; 1158 auto maybe_load_addr = ResolveLoadAddress( 1159 exe_ctx, module_sp, error_ptr, "DW_OP_deref", file_addr, so_addr); 1160 1161 if (!maybe_load_addr) 1162 return false; 1163 1164 stack.back().GetScalar() = *maybe_load_addr; 1165 // Fall through to load address promotion code below. 1166 } LLVM_FALLTHROUGH; 1167 case Value::ValueType::Scalar: 1168 // Promote Scalar to LoadAddress and fall through. 1169 stack.back().SetValueType(Value::ValueType::LoadAddress); 1170 LLVM_FALLTHROUGH; 1171 case Value::ValueType::LoadAddress: 1172 if (exe_ctx) { 1173 if (process) { 1174 lldb::addr_t pointer_addr = 1175 stack.back().GetScalar().ULongLong(LLDB_INVALID_ADDRESS); 1176 Status error; 1177 lldb::addr_t pointer_value = 1178 process->ReadPointerFromMemory(pointer_addr, error); 1179 if (pointer_value != LLDB_INVALID_ADDRESS) { 1180 if (ABISP abi_sp = process->GetABI()) 1181 pointer_value = abi_sp->FixCodeAddress(pointer_value); 1182 stack.back().GetScalar() = pointer_value; 1183 stack.back().ClearContext(); 1184 } else { 1185 if (error_ptr) 1186 error_ptr->SetErrorStringWithFormat( 1187 "Failed to dereference pointer from 0x%" PRIx64 1188 " for DW_OP_deref: %s\n", 1189 pointer_addr, error.AsCString()); 1190 return false; 1191 } 1192 } else { 1193 if (error_ptr) 1194 error_ptr->SetErrorString("NULL process for DW_OP_deref.\n"); 1195 return false; 1196 } 1197 } else { 1198 if (error_ptr) 1199 error_ptr->SetErrorString( 1200 "NULL execution context for DW_OP_deref.\n"); 1201 return false; 1202 } 1203 break; 1204 1205 case Value::ValueType::Invalid: 1206 if (error_ptr) 1207 error_ptr->SetErrorString("Invalid value type for DW_OP_deref.\n"); 1208 return false; 1209 } 1210 1211 } break; 1212 1213 // OPCODE: DW_OP_deref_size 1214 // OPERANDS: 1 1215 // 1 - uint8_t that specifies the size of the data to dereference. 1216 // DESCRIPTION: Behaves like the DW_OP_deref operation: it pops the top 1217 // stack entry and treats it as an address. The value retrieved from that 1218 // address is pushed. In the DW_OP_deref_size operation, however, the size 1219 // in bytes of the data retrieved from the dereferenced address is 1220 // specified by the single operand. This operand is a 1-byte unsigned 1221 // integral constant whose value may not be larger than the size of an 1222 // address on the target machine. The data retrieved is zero extended to 1223 // the size of an address on the target machine before being pushed on the 1224 // expression stack. 1225 case DW_OP_deref_size: { 1226 if (stack.empty()) { 1227 if (error_ptr) 1228 error_ptr->SetErrorString( 1229 "Expression stack empty for DW_OP_deref_size."); 1230 return false; 1231 } 1232 uint8_t size = opcodes.GetU8(&offset); 1233 Value::ValueType value_type = stack.back().GetValueType(); 1234 switch (value_type) { 1235 case Value::ValueType::HostAddress: { 1236 void *src = (void *)stack.back().GetScalar().ULongLong(); 1237 intptr_t ptr; 1238 ::memcpy(&ptr, src, sizeof(void *)); 1239 // I can't decide whether the size operand should apply to the bytes in 1240 // their 1241 // lldb-host endianness or the target endianness.. I doubt this'll ever 1242 // come up but I'll opt for assuming big endian regardless. 1243 switch (size) { 1244 case 1: 1245 ptr = ptr & 0xff; 1246 break; 1247 case 2: 1248 ptr = ptr & 0xffff; 1249 break; 1250 case 3: 1251 ptr = ptr & 0xffffff; 1252 break; 1253 case 4: 1254 ptr = ptr & 0xffffffff; 1255 break; 1256 // the casts are added to work around the case where intptr_t is a 32 1257 // bit quantity; 1258 // presumably we won't hit the 5..7 cases if (void*) is 32-bits in this 1259 // program. 1260 case 5: 1261 ptr = (intptr_t)ptr & 0xffffffffffULL; 1262 break; 1263 case 6: 1264 ptr = (intptr_t)ptr & 0xffffffffffffULL; 1265 break; 1266 case 7: 1267 ptr = (intptr_t)ptr & 0xffffffffffffffULL; 1268 break; 1269 default: 1270 break; 1271 } 1272 stack.back().GetScalar() = ptr; 1273 stack.back().ClearContext(); 1274 } break; 1275 case Value::ValueType::FileAddress: { 1276 auto file_addr = 1277 stack.back().GetScalar().ULongLong(LLDB_INVALID_ADDRESS); 1278 Address so_addr; 1279 auto maybe_load_addr = 1280 ResolveLoadAddress(exe_ctx, module_sp, error_ptr, 1281 "DW_OP_deref_size", file_addr, so_addr, 1282 /*check_sectionoffset=*/true); 1283 1284 if (!maybe_load_addr) 1285 return false; 1286 1287 addr_t load_addr = *maybe_load_addr; 1288 1289 if (load_addr == LLDB_INVALID_ADDRESS && so_addr.IsSectionOffset()) { 1290 uint8_t addr_bytes[8]; 1291 Status error; 1292 1293 if (exe_ctx->GetTargetRef().ReadMemory( 1294 so_addr, &addr_bytes, size, error, 1295 /*force_live_memory=*/false) == size) { 1296 ObjectFile *objfile = module_sp->GetObjectFile(); 1297 1298 stack.back().GetScalar() = DerefSizeExtractDataHelper( 1299 addr_bytes, size, objfile->GetByteOrder(), size); 1300 stack.back().ClearContext(); 1301 break; 1302 } else { 1303 if (error_ptr) 1304 error_ptr->SetErrorStringWithFormat( 1305 "Failed to dereference pointer for for DW_OP_deref_size: " 1306 "%s\n", 1307 error.AsCString()); 1308 return false; 1309 } 1310 } 1311 stack.back().GetScalar() = load_addr; 1312 // Fall through to load address promotion code below. 1313 } 1314 1315 LLVM_FALLTHROUGH; 1316 case Value::ValueType::Scalar: 1317 case Value::ValueType::LoadAddress: 1318 if (exe_ctx) { 1319 if (process) { 1320 lldb::addr_t pointer_addr = 1321 stack.back().GetScalar().ULongLong(LLDB_INVALID_ADDRESS); 1322 uint8_t addr_bytes[sizeof(lldb::addr_t)]; 1323 Status error; 1324 if (process->ReadMemory(pointer_addr, &addr_bytes, size, error) == 1325 size) { 1326 1327 stack.back().GetScalar() = 1328 DerefSizeExtractDataHelper(addr_bytes, sizeof(addr_bytes), 1329 process->GetByteOrder(), size); 1330 stack.back().ClearContext(); 1331 } else { 1332 if (error_ptr) 1333 error_ptr->SetErrorStringWithFormat( 1334 "Failed to dereference pointer from 0x%" PRIx64 1335 " for DW_OP_deref: %s\n", 1336 pointer_addr, error.AsCString()); 1337 return false; 1338 } 1339 } else { 1340 if (error_ptr) 1341 error_ptr->SetErrorString("NULL process for DW_OP_deref_size.\n"); 1342 return false; 1343 } 1344 } else { 1345 if (error_ptr) 1346 error_ptr->SetErrorString( 1347 "NULL execution context for DW_OP_deref_size.\n"); 1348 return false; 1349 } 1350 break; 1351 1352 case Value::ValueType::Invalid: 1353 if (error_ptr) 1354 error_ptr->SetErrorString("Invalid value for DW_OP_deref_size.\n"); 1355 return false; 1356 } 1357 1358 } break; 1359 1360 // OPCODE: DW_OP_xderef_size 1361 // OPERANDS: 1 1362 // 1 - uint8_t that specifies the size of the data to dereference. 1363 // DESCRIPTION: Behaves like the DW_OP_xderef operation: the entry at 1364 // the top of the stack is treated as an address. The second stack entry is 1365 // treated as an "address space identifier" for those architectures that 1366 // support multiple address spaces. The top two stack elements are popped, 1367 // a data item is retrieved through an implementation-defined address 1368 // calculation and pushed as the new stack top. In the DW_OP_xderef_size 1369 // operation, however, the size in bytes of the data retrieved from the 1370 // dereferenced address is specified by the single operand. This operand is 1371 // a 1-byte unsigned integral constant whose value may not be larger than 1372 // the size of an address on the target machine. The data retrieved is zero 1373 // extended to the size of an address on the target machine before being 1374 // pushed on the expression stack. 1375 case DW_OP_xderef_size: 1376 if (error_ptr) 1377 error_ptr->SetErrorString("Unimplemented opcode: DW_OP_xderef_size."); 1378 return false; 1379 // OPCODE: DW_OP_xderef 1380 // OPERANDS: none 1381 // DESCRIPTION: Provides an extended dereference mechanism. The entry at 1382 // the top of the stack is treated as an address. The second stack entry is 1383 // treated as an "address space identifier" for those architectures that 1384 // support multiple address spaces. The top two stack elements are popped, 1385 // a data item is retrieved through an implementation-defined address 1386 // calculation and pushed as the new stack top. The size of the data 1387 // retrieved from the dereferenced address is the size of an address on the 1388 // target machine. 1389 case DW_OP_xderef: 1390 if (error_ptr) 1391 error_ptr->SetErrorString("Unimplemented opcode: DW_OP_xderef."); 1392 return false; 1393 1394 // All DW_OP_constXXX opcodes have a single operand as noted below: 1395 // 1396 // Opcode Operand 1 1397 // DW_OP_const1u 1-byte unsigned integer constant 1398 // DW_OP_const1s 1-byte signed integer constant 1399 // DW_OP_const2u 2-byte unsigned integer constant 1400 // DW_OP_const2s 2-byte signed integer constant 1401 // DW_OP_const4u 4-byte unsigned integer constant 1402 // DW_OP_const4s 4-byte signed integer constant 1403 // DW_OP_const8u 8-byte unsigned integer constant 1404 // DW_OP_const8s 8-byte signed integer constant 1405 // DW_OP_constu unsigned LEB128 integer constant 1406 // DW_OP_consts signed LEB128 integer constant 1407 case DW_OP_const1u: 1408 stack.push_back(to_generic(opcodes.GetU8(&offset))); 1409 break; 1410 case DW_OP_const1s: 1411 stack.push_back(to_generic((int8_t)opcodes.GetU8(&offset))); 1412 break; 1413 case DW_OP_const2u: 1414 stack.push_back(to_generic(opcodes.GetU16(&offset))); 1415 break; 1416 case DW_OP_const2s: 1417 stack.push_back(to_generic((int16_t)opcodes.GetU16(&offset))); 1418 break; 1419 case DW_OP_const4u: 1420 stack.push_back(to_generic(opcodes.GetU32(&offset))); 1421 break; 1422 case DW_OP_const4s: 1423 stack.push_back(to_generic((int32_t)opcodes.GetU32(&offset))); 1424 break; 1425 case DW_OP_const8u: 1426 stack.push_back(to_generic(opcodes.GetU64(&offset))); 1427 break; 1428 case DW_OP_const8s: 1429 stack.push_back(to_generic((int64_t)opcodes.GetU64(&offset))); 1430 break; 1431 // These should also use to_generic, but we can't do that due to a 1432 // producer-side bug in llvm. See llvm.org/pr48087. 1433 case DW_OP_constu: 1434 stack.push_back(Scalar(opcodes.GetULEB128(&offset))); 1435 break; 1436 case DW_OP_consts: 1437 stack.push_back(Scalar(opcodes.GetSLEB128(&offset))); 1438 break; 1439 1440 // OPCODE: DW_OP_dup 1441 // OPERANDS: none 1442 // DESCRIPTION: duplicates the value at the top of the stack 1443 case DW_OP_dup: 1444 if (stack.empty()) { 1445 if (error_ptr) 1446 error_ptr->SetErrorString("Expression stack empty for DW_OP_dup."); 1447 return false; 1448 } else 1449 stack.push_back(stack.back()); 1450 break; 1451 1452 // OPCODE: DW_OP_drop 1453 // OPERANDS: none 1454 // DESCRIPTION: pops the value at the top of the stack 1455 case DW_OP_drop: 1456 if (stack.empty()) { 1457 if (error_ptr) 1458 error_ptr->SetErrorString("Expression stack empty for DW_OP_drop."); 1459 return false; 1460 } else 1461 stack.pop_back(); 1462 break; 1463 1464 // OPCODE: DW_OP_over 1465 // OPERANDS: none 1466 // DESCRIPTION: Duplicates the entry currently second in the stack at 1467 // the top of the stack. 1468 case DW_OP_over: 1469 if (stack.size() < 2) { 1470 if (error_ptr) 1471 error_ptr->SetErrorString( 1472 "Expression stack needs at least 2 items for DW_OP_over."); 1473 return false; 1474 } else 1475 stack.push_back(stack[stack.size() - 2]); 1476 break; 1477 1478 // OPCODE: DW_OP_pick 1479 // OPERANDS: uint8_t index into the current stack 1480 // DESCRIPTION: The stack entry with the specified index (0 through 255, 1481 // inclusive) is pushed on the stack 1482 case DW_OP_pick: { 1483 uint8_t pick_idx = opcodes.GetU8(&offset); 1484 if (pick_idx < stack.size()) 1485 stack.push_back(stack[stack.size() - 1 - pick_idx]); 1486 else { 1487 if (error_ptr) 1488 error_ptr->SetErrorStringWithFormat( 1489 "Index %u out of range for DW_OP_pick.\n", pick_idx); 1490 return false; 1491 } 1492 } break; 1493 1494 // OPCODE: DW_OP_swap 1495 // OPERANDS: none 1496 // DESCRIPTION: swaps the top two stack entries. The entry at the top 1497 // of the stack becomes the second stack entry, and the second entry 1498 // becomes the top of the stack 1499 case DW_OP_swap: 1500 if (stack.size() < 2) { 1501 if (error_ptr) 1502 error_ptr->SetErrorString( 1503 "Expression stack needs at least 2 items for DW_OP_swap."); 1504 return false; 1505 } else { 1506 tmp = stack.back(); 1507 stack.back() = stack[stack.size() - 2]; 1508 stack[stack.size() - 2] = tmp; 1509 } 1510 break; 1511 1512 // OPCODE: DW_OP_rot 1513 // OPERANDS: none 1514 // DESCRIPTION: Rotates the first three stack entries. The entry at 1515 // the top of the stack becomes the third stack entry, the second entry 1516 // becomes the top of the stack, and the third entry becomes the second 1517 // entry. 1518 case DW_OP_rot: 1519 if (stack.size() < 3) { 1520 if (error_ptr) 1521 error_ptr->SetErrorString( 1522 "Expression stack needs at least 3 items for DW_OP_rot."); 1523 return false; 1524 } else { 1525 size_t last_idx = stack.size() - 1; 1526 Value old_top = stack[last_idx]; 1527 stack[last_idx] = stack[last_idx - 1]; 1528 stack[last_idx - 1] = stack[last_idx - 2]; 1529 stack[last_idx - 2] = old_top; 1530 } 1531 break; 1532 1533 // OPCODE: DW_OP_abs 1534 // OPERANDS: none 1535 // DESCRIPTION: pops the top stack entry, interprets it as a signed 1536 // value and pushes its absolute value. If the absolute value can not be 1537 // represented, the result is undefined. 1538 case DW_OP_abs: 1539 if (stack.empty()) { 1540 if (error_ptr) 1541 error_ptr->SetErrorString( 1542 "Expression stack needs at least 1 item for DW_OP_abs."); 1543 return false; 1544 } else if (!stack.back().ResolveValue(exe_ctx).AbsoluteValue()) { 1545 if (error_ptr) 1546 error_ptr->SetErrorString( 1547 "Failed to take the absolute value of the first stack item."); 1548 return false; 1549 } 1550 break; 1551 1552 // OPCODE: DW_OP_and 1553 // OPERANDS: none 1554 // DESCRIPTION: pops the top two stack values, performs a bitwise and 1555 // operation on the two, and pushes the result. 1556 case DW_OP_and: 1557 if (stack.size() < 2) { 1558 if (error_ptr) 1559 error_ptr->SetErrorString( 1560 "Expression stack needs at least 2 items for DW_OP_and."); 1561 return false; 1562 } else { 1563 tmp = stack.back(); 1564 stack.pop_back(); 1565 stack.back().ResolveValue(exe_ctx) = 1566 stack.back().ResolveValue(exe_ctx) & tmp.ResolveValue(exe_ctx); 1567 } 1568 break; 1569 1570 // OPCODE: DW_OP_div 1571 // OPERANDS: none 1572 // DESCRIPTION: pops the top two stack values, divides the former second 1573 // entry by the former top of the stack using signed division, and pushes 1574 // the result. 1575 case DW_OP_div: 1576 if (stack.size() < 2) { 1577 if (error_ptr) 1578 error_ptr->SetErrorString( 1579 "Expression stack needs at least 2 items for DW_OP_div."); 1580 return false; 1581 } else { 1582 tmp = stack.back(); 1583 if (tmp.ResolveValue(exe_ctx).IsZero()) { 1584 if (error_ptr) 1585 error_ptr->SetErrorString("Divide by zero."); 1586 return false; 1587 } else { 1588 stack.pop_back(); 1589 stack.back() = 1590 stack.back().ResolveValue(exe_ctx) / tmp.ResolveValue(exe_ctx); 1591 if (!stack.back().ResolveValue(exe_ctx).IsValid()) { 1592 if (error_ptr) 1593 error_ptr->SetErrorString("Divide failed."); 1594 return false; 1595 } 1596 } 1597 } 1598 break; 1599 1600 // OPCODE: DW_OP_minus 1601 // OPERANDS: none 1602 // DESCRIPTION: pops the top two stack values, subtracts the former top 1603 // of the stack from the former second entry, and pushes the result. 1604 case DW_OP_minus: 1605 if (stack.size() < 2) { 1606 if (error_ptr) 1607 error_ptr->SetErrorString( 1608 "Expression stack needs at least 2 items for DW_OP_minus."); 1609 return false; 1610 } else { 1611 tmp = stack.back(); 1612 stack.pop_back(); 1613 stack.back().ResolveValue(exe_ctx) = 1614 stack.back().ResolveValue(exe_ctx) - tmp.ResolveValue(exe_ctx); 1615 } 1616 break; 1617 1618 // OPCODE: DW_OP_mod 1619 // OPERANDS: none 1620 // DESCRIPTION: pops the top two stack values and pushes the result of 1621 // the calculation: former second stack entry modulo the former top of the 1622 // stack. 1623 case DW_OP_mod: 1624 if (stack.size() < 2) { 1625 if (error_ptr) 1626 error_ptr->SetErrorString( 1627 "Expression stack needs at least 2 items for DW_OP_mod."); 1628 return false; 1629 } else { 1630 tmp = stack.back(); 1631 stack.pop_back(); 1632 stack.back().ResolveValue(exe_ctx) = 1633 stack.back().ResolveValue(exe_ctx) % tmp.ResolveValue(exe_ctx); 1634 } 1635 break; 1636 1637 // OPCODE: DW_OP_mul 1638 // OPERANDS: none 1639 // DESCRIPTION: pops the top two stack entries, multiplies them 1640 // together, and pushes the result. 1641 case DW_OP_mul: 1642 if (stack.size() < 2) { 1643 if (error_ptr) 1644 error_ptr->SetErrorString( 1645 "Expression stack needs at least 2 items for DW_OP_mul."); 1646 return false; 1647 } else { 1648 tmp = stack.back(); 1649 stack.pop_back(); 1650 stack.back().ResolveValue(exe_ctx) = 1651 stack.back().ResolveValue(exe_ctx) * tmp.ResolveValue(exe_ctx); 1652 } 1653 break; 1654 1655 // OPCODE: DW_OP_neg 1656 // OPERANDS: none 1657 // DESCRIPTION: pops the top stack entry, and pushes its negation. 1658 case DW_OP_neg: 1659 if (stack.empty()) { 1660 if (error_ptr) 1661 error_ptr->SetErrorString( 1662 "Expression stack needs at least 1 item for DW_OP_neg."); 1663 return false; 1664 } else { 1665 if (!stack.back().ResolveValue(exe_ctx).UnaryNegate()) { 1666 if (error_ptr) 1667 error_ptr->SetErrorString("Unary negate failed."); 1668 return false; 1669 } 1670 } 1671 break; 1672 1673 // OPCODE: DW_OP_not 1674 // OPERANDS: none 1675 // DESCRIPTION: pops the top stack entry, and pushes its bitwise 1676 // complement 1677 case DW_OP_not: 1678 if (stack.empty()) { 1679 if (error_ptr) 1680 error_ptr->SetErrorString( 1681 "Expression stack needs at least 1 item for DW_OP_not."); 1682 return false; 1683 } else { 1684 if (!stack.back().ResolveValue(exe_ctx).OnesComplement()) { 1685 if (error_ptr) 1686 error_ptr->SetErrorString("Logical NOT failed."); 1687 return false; 1688 } 1689 } 1690 break; 1691 1692 // OPCODE: DW_OP_or 1693 // OPERANDS: none 1694 // DESCRIPTION: pops the top two stack entries, performs a bitwise or 1695 // operation on the two, and pushes the result. 1696 case DW_OP_or: 1697 if (stack.size() < 2) { 1698 if (error_ptr) 1699 error_ptr->SetErrorString( 1700 "Expression stack needs at least 2 items for DW_OP_or."); 1701 return false; 1702 } else { 1703 tmp = stack.back(); 1704 stack.pop_back(); 1705 stack.back().ResolveValue(exe_ctx) = 1706 stack.back().ResolveValue(exe_ctx) | tmp.ResolveValue(exe_ctx); 1707 } 1708 break; 1709 1710 // OPCODE: DW_OP_plus 1711 // OPERANDS: none 1712 // DESCRIPTION: pops the top two stack entries, adds them together, and 1713 // pushes the result. 1714 case DW_OP_plus: 1715 if (stack.size() < 2) { 1716 if (error_ptr) 1717 error_ptr->SetErrorString( 1718 "Expression stack needs at least 2 items for DW_OP_plus."); 1719 return false; 1720 } else { 1721 tmp = stack.back(); 1722 stack.pop_back(); 1723 stack.back().GetScalar() += tmp.GetScalar(); 1724 } 1725 break; 1726 1727 // OPCODE: DW_OP_plus_uconst 1728 // OPERANDS: none 1729 // DESCRIPTION: pops the top stack entry, adds it to the unsigned LEB128 1730 // constant operand and pushes the result. 1731 case DW_OP_plus_uconst: 1732 if (stack.empty()) { 1733 if (error_ptr) 1734 error_ptr->SetErrorString( 1735 "Expression stack needs at least 1 item for DW_OP_plus_uconst."); 1736 return false; 1737 } else { 1738 const uint64_t uconst_value = opcodes.GetULEB128(&offset); 1739 // Implicit conversion from a UINT to a Scalar... 1740 stack.back().GetScalar() += uconst_value; 1741 if (!stack.back().GetScalar().IsValid()) { 1742 if (error_ptr) 1743 error_ptr->SetErrorString("DW_OP_plus_uconst failed."); 1744 return false; 1745 } 1746 } 1747 break; 1748 1749 // OPCODE: DW_OP_shl 1750 // OPERANDS: none 1751 // DESCRIPTION: pops the top two stack entries, shifts the former 1752 // second entry left by the number of bits specified by the former top of 1753 // the stack, and pushes the result. 1754 case DW_OP_shl: 1755 if (stack.size() < 2) { 1756 if (error_ptr) 1757 error_ptr->SetErrorString( 1758 "Expression stack needs at least 2 items for DW_OP_shl."); 1759 return false; 1760 } else { 1761 tmp = stack.back(); 1762 stack.pop_back(); 1763 stack.back().ResolveValue(exe_ctx) <<= tmp.ResolveValue(exe_ctx); 1764 } 1765 break; 1766 1767 // OPCODE: DW_OP_shr 1768 // OPERANDS: none 1769 // DESCRIPTION: pops the top two stack entries, shifts the former second 1770 // entry right logically (filling with zero bits) by the number of bits 1771 // specified by the former top of the stack, and pushes the result. 1772 case DW_OP_shr: 1773 if (stack.size() < 2) { 1774 if (error_ptr) 1775 error_ptr->SetErrorString( 1776 "Expression stack needs at least 2 items for DW_OP_shr."); 1777 return false; 1778 } else { 1779 tmp = stack.back(); 1780 stack.pop_back(); 1781 if (!stack.back().ResolveValue(exe_ctx).ShiftRightLogical( 1782 tmp.ResolveValue(exe_ctx))) { 1783 if (error_ptr) 1784 error_ptr->SetErrorString("DW_OP_shr failed."); 1785 return false; 1786 } 1787 } 1788 break; 1789 1790 // OPCODE: DW_OP_shra 1791 // OPERANDS: none 1792 // DESCRIPTION: pops the top two stack entries, shifts the former second 1793 // entry right arithmetically (divide the magnitude by 2, keep the same 1794 // sign for the result) by the number of bits specified by the former top 1795 // of the stack, and pushes the result. 1796 case DW_OP_shra: 1797 if (stack.size() < 2) { 1798 if (error_ptr) 1799 error_ptr->SetErrorString( 1800 "Expression stack needs at least 2 items for DW_OP_shra."); 1801 return false; 1802 } else { 1803 tmp = stack.back(); 1804 stack.pop_back(); 1805 stack.back().ResolveValue(exe_ctx) >>= tmp.ResolveValue(exe_ctx); 1806 } 1807 break; 1808 1809 // OPCODE: DW_OP_xor 1810 // OPERANDS: none 1811 // DESCRIPTION: pops the top two stack entries, performs the bitwise 1812 // exclusive-or operation on the two, and pushes the result. 1813 case DW_OP_xor: 1814 if (stack.size() < 2) { 1815 if (error_ptr) 1816 error_ptr->SetErrorString( 1817 "Expression stack needs at least 2 items for DW_OP_xor."); 1818 return false; 1819 } else { 1820 tmp = stack.back(); 1821 stack.pop_back(); 1822 stack.back().ResolveValue(exe_ctx) = 1823 stack.back().ResolveValue(exe_ctx) ^ tmp.ResolveValue(exe_ctx); 1824 } 1825 break; 1826 1827 // OPCODE: DW_OP_skip 1828 // OPERANDS: int16_t 1829 // DESCRIPTION: An unconditional branch. Its single operand is a 2-byte 1830 // signed integer constant. The 2-byte constant is the number of bytes of 1831 // the DWARF expression to skip forward or backward from the current 1832 // operation, beginning after the 2-byte constant. 1833 case DW_OP_skip: { 1834 int16_t skip_offset = (int16_t)opcodes.GetU16(&offset); 1835 lldb::offset_t new_offset = offset + skip_offset; 1836 if (opcodes.ValidOffset(new_offset)) 1837 offset = new_offset; 1838 else { 1839 if (error_ptr) 1840 error_ptr->SetErrorString("Invalid opcode offset in DW_OP_skip."); 1841 return false; 1842 } 1843 } break; 1844 1845 // OPCODE: DW_OP_bra 1846 // OPERANDS: int16_t 1847 // DESCRIPTION: A conditional branch. Its single operand is a 2-byte 1848 // signed integer constant. This operation pops the top of stack. If the 1849 // value popped is not the constant 0, the 2-byte constant operand is the 1850 // number of bytes of the DWARF expression to skip forward or backward from 1851 // the current operation, beginning after the 2-byte constant. 1852 case DW_OP_bra: 1853 if (stack.empty()) { 1854 if (error_ptr) 1855 error_ptr->SetErrorString( 1856 "Expression stack needs at least 1 item for DW_OP_bra."); 1857 return false; 1858 } else { 1859 tmp = stack.back(); 1860 stack.pop_back(); 1861 int16_t bra_offset = (int16_t)opcodes.GetU16(&offset); 1862 Scalar zero(0); 1863 if (tmp.ResolveValue(exe_ctx) != zero) { 1864 lldb::offset_t new_offset = offset + bra_offset; 1865 if (opcodes.ValidOffset(new_offset)) 1866 offset = new_offset; 1867 else { 1868 if (error_ptr) 1869 error_ptr->SetErrorString("Invalid opcode offset in DW_OP_bra."); 1870 return false; 1871 } 1872 } 1873 } 1874 break; 1875 1876 // OPCODE: DW_OP_eq 1877 // OPERANDS: none 1878 // DESCRIPTION: pops the top two stack values, compares using the 1879 // equals (==) operator. 1880 // STACK RESULT: push the constant value 1 onto the stack if the result 1881 // of the operation is true or the constant value 0 if the result of the 1882 // operation is false. 1883 case DW_OP_eq: 1884 if (stack.size() < 2) { 1885 if (error_ptr) 1886 error_ptr->SetErrorString( 1887 "Expression stack needs at least 2 items for DW_OP_eq."); 1888 return false; 1889 } else { 1890 tmp = stack.back(); 1891 stack.pop_back(); 1892 stack.back().ResolveValue(exe_ctx) = 1893 stack.back().ResolveValue(exe_ctx) == tmp.ResolveValue(exe_ctx); 1894 } 1895 break; 1896 1897 // OPCODE: DW_OP_ge 1898 // OPERANDS: none 1899 // DESCRIPTION: pops the top two stack values, compares using the 1900 // greater than or equal to (>=) operator. 1901 // STACK RESULT: push the constant value 1 onto the stack if the result 1902 // of the operation is true or the constant value 0 if the result of the 1903 // operation is false. 1904 case DW_OP_ge: 1905 if (stack.size() < 2) { 1906 if (error_ptr) 1907 error_ptr->SetErrorString( 1908 "Expression stack needs at least 2 items for DW_OP_ge."); 1909 return false; 1910 } else { 1911 tmp = stack.back(); 1912 stack.pop_back(); 1913 stack.back().ResolveValue(exe_ctx) = 1914 stack.back().ResolveValue(exe_ctx) >= tmp.ResolveValue(exe_ctx); 1915 } 1916 break; 1917 1918 // OPCODE: DW_OP_gt 1919 // OPERANDS: none 1920 // DESCRIPTION: pops the top two stack values, compares using the 1921 // greater than (>) operator. 1922 // STACK RESULT: push the constant value 1 onto the stack if the result 1923 // of the operation is true or the constant value 0 if the result of the 1924 // operation is false. 1925 case DW_OP_gt: 1926 if (stack.size() < 2) { 1927 if (error_ptr) 1928 error_ptr->SetErrorString( 1929 "Expression stack needs at least 2 items for DW_OP_gt."); 1930 return false; 1931 } else { 1932 tmp = stack.back(); 1933 stack.pop_back(); 1934 stack.back().ResolveValue(exe_ctx) = 1935 stack.back().ResolveValue(exe_ctx) > tmp.ResolveValue(exe_ctx); 1936 } 1937 break; 1938 1939 // OPCODE: DW_OP_le 1940 // OPERANDS: none 1941 // DESCRIPTION: pops the top two stack values, compares using the 1942 // less than or equal to (<=) operator. 1943 // STACK RESULT: push the constant value 1 onto the stack if the result 1944 // of the operation is true or the constant value 0 if the result of the 1945 // operation is false. 1946 case DW_OP_le: 1947 if (stack.size() < 2) { 1948 if (error_ptr) 1949 error_ptr->SetErrorString( 1950 "Expression stack needs at least 2 items for DW_OP_le."); 1951 return false; 1952 } else { 1953 tmp = stack.back(); 1954 stack.pop_back(); 1955 stack.back().ResolveValue(exe_ctx) = 1956 stack.back().ResolveValue(exe_ctx) <= tmp.ResolveValue(exe_ctx); 1957 } 1958 break; 1959 1960 // OPCODE: DW_OP_lt 1961 // OPERANDS: none 1962 // DESCRIPTION: pops the top two stack values, compares using the 1963 // less than (<) operator. 1964 // STACK RESULT: push the constant value 1 onto the stack if the result 1965 // of the operation is true or the constant value 0 if the result of the 1966 // operation is false. 1967 case DW_OP_lt: 1968 if (stack.size() < 2) { 1969 if (error_ptr) 1970 error_ptr->SetErrorString( 1971 "Expression stack needs at least 2 items for DW_OP_lt."); 1972 return false; 1973 } else { 1974 tmp = stack.back(); 1975 stack.pop_back(); 1976 stack.back().ResolveValue(exe_ctx) = 1977 stack.back().ResolveValue(exe_ctx) < tmp.ResolveValue(exe_ctx); 1978 } 1979 break; 1980 1981 // OPCODE: DW_OP_ne 1982 // OPERANDS: none 1983 // DESCRIPTION: pops the top two stack values, compares using the 1984 // not equal (!=) operator. 1985 // STACK RESULT: push the constant value 1 onto the stack if the result 1986 // of the operation is true or the constant value 0 if the result of the 1987 // operation is false. 1988 case DW_OP_ne: 1989 if (stack.size() < 2) { 1990 if (error_ptr) 1991 error_ptr->SetErrorString( 1992 "Expression stack needs at least 2 items for DW_OP_ne."); 1993 return false; 1994 } else { 1995 tmp = stack.back(); 1996 stack.pop_back(); 1997 stack.back().ResolveValue(exe_ctx) = 1998 stack.back().ResolveValue(exe_ctx) != tmp.ResolveValue(exe_ctx); 1999 } 2000 break; 2001 2002 // OPCODE: DW_OP_litn 2003 // OPERANDS: none 2004 // DESCRIPTION: encode the unsigned literal values from 0 through 31. 2005 // STACK RESULT: push the unsigned literal constant value onto the top 2006 // of the stack. 2007 case DW_OP_lit0: 2008 case DW_OP_lit1: 2009 case DW_OP_lit2: 2010 case DW_OP_lit3: 2011 case DW_OP_lit4: 2012 case DW_OP_lit5: 2013 case DW_OP_lit6: 2014 case DW_OP_lit7: 2015 case DW_OP_lit8: 2016 case DW_OP_lit9: 2017 case DW_OP_lit10: 2018 case DW_OP_lit11: 2019 case DW_OP_lit12: 2020 case DW_OP_lit13: 2021 case DW_OP_lit14: 2022 case DW_OP_lit15: 2023 case DW_OP_lit16: 2024 case DW_OP_lit17: 2025 case DW_OP_lit18: 2026 case DW_OP_lit19: 2027 case DW_OP_lit20: 2028 case DW_OP_lit21: 2029 case DW_OP_lit22: 2030 case DW_OP_lit23: 2031 case DW_OP_lit24: 2032 case DW_OP_lit25: 2033 case DW_OP_lit26: 2034 case DW_OP_lit27: 2035 case DW_OP_lit28: 2036 case DW_OP_lit29: 2037 case DW_OP_lit30: 2038 case DW_OP_lit31: 2039 stack.push_back(to_generic(op - DW_OP_lit0)); 2040 break; 2041 2042 // OPCODE: DW_OP_regN 2043 // OPERANDS: none 2044 // DESCRIPTION: Push the value in register n on the top of the stack. 2045 case DW_OP_reg0: 2046 case DW_OP_reg1: 2047 case DW_OP_reg2: 2048 case DW_OP_reg3: 2049 case DW_OP_reg4: 2050 case DW_OP_reg5: 2051 case DW_OP_reg6: 2052 case DW_OP_reg7: 2053 case DW_OP_reg8: 2054 case DW_OP_reg9: 2055 case DW_OP_reg10: 2056 case DW_OP_reg11: 2057 case DW_OP_reg12: 2058 case DW_OP_reg13: 2059 case DW_OP_reg14: 2060 case DW_OP_reg15: 2061 case DW_OP_reg16: 2062 case DW_OP_reg17: 2063 case DW_OP_reg18: 2064 case DW_OP_reg19: 2065 case DW_OP_reg20: 2066 case DW_OP_reg21: 2067 case DW_OP_reg22: 2068 case DW_OP_reg23: 2069 case DW_OP_reg24: 2070 case DW_OP_reg25: 2071 case DW_OP_reg26: 2072 case DW_OP_reg27: 2073 case DW_OP_reg28: 2074 case DW_OP_reg29: 2075 case DW_OP_reg30: 2076 case DW_OP_reg31: { 2077 dwarf4_location_description_kind = Register; 2078 reg_num = op - DW_OP_reg0; 2079 2080 if (ReadRegisterValueAsScalar(reg_ctx, reg_kind, reg_num, error_ptr, tmp)) 2081 stack.push_back(tmp); 2082 else 2083 return false; 2084 } break; 2085 // OPCODE: DW_OP_regx 2086 // OPERANDS: 2087 // ULEB128 literal operand that encodes the register. 2088 // DESCRIPTION: Push the value in register on the top of the stack. 2089 case DW_OP_regx: { 2090 dwarf4_location_description_kind = Register; 2091 reg_num = opcodes.GetULEB128(&offset); 2092 if (ReadRegisterValueAsScalar(reg_ctx, reg_kind, reg_num, error_ptr, tmp)) 2093 stack.push_back(tmp); 2094 else 2095 return false; 2096 } break; 2097 2098 // OPCODE: DW_OP_bregN 2099 // OPERANDS: 2100 // SLEB128 offset from register N 2101 // DESCRIPTION: Value is in memory at the address specified by register 2102 // N plus an offset. 2103 case DW_OP_breg0: 2104 case DW_OP_breg1: 2105 case DW_OP_breg2: 2106 case DW_OP_breg3: 2107 case DW_OP_breg4: 2108 case DW_OP_breg5: 2109 case DW_OP_breg6: 2110 case DW_OP_breg7: 2111 case DW_OP_breg8: 2112 case DW_OP_breg9: 2113 case DW_OP_breg10: 2114 case DW_OP_breg11: 2115 case DW_OP_breg12: 2116 case DW_OP_breg13: 2117 case DW_OP_breg14: 2118 case DW_OP_breg15: 2119 case DW_OP_breg16: 2120 case DW_OP_breg17: 2121 case DW_OP_breg18: 2122 case DW_OP_breg19: 2123 case DW_OP_breg20: 2124 case DW_OP_breg21: 2125 case DW_OP_breg22: 2126 case DW_OP_breg23: 2127 case DW_OP_breg24: 2128 case DW_OP_breg25: 2129 case DW_OP_breg26: 2130 case DW_OP_breg27: 2131 case DW_OP_breg28: 2132 case DW_OP_breg29: 2133 case DW_OP_breg30: 2134 case DW_OP_breg31: { 2135 reg_num = op - DW_OP_breg0; 2136 2137 if (ReadRegisterValueAsScalar(reg_ctx, reg_kind, reg_num, error_ptr, 2138 tmp)) { 2139 int64_t breg_offset = opcodes.GetSLEB128(&offset); 2140 tmp.ResolveValue(exe_ctx) += (uint64_t)breg_offset; 2141 tmp.ClearContext(); 2142 stack.push_back(tmp); 2143 stack.back().SetValueType(Value::ValueType::LoadAddress); 2144 } else 2145 return false; 2146 } break; 2147 // OPCODE: DW_OP_bregx 2148 // OPERANDS: 2 2149 // ULEB128 literal operand that encodes the register. 2150 // SLEB128 offset from register N 2151 // DESCRIPTION: Value is in memory at the address specified by register 2152 // N plus an offset. 2153 case DW_OP_bregx: { 2154 reg_num = opcodes.GetULEB128(&offset); 2155 2156 if (ReadRegisterValueAsScalar(reg_ctx, reg_kind, reg_num, error_ptr, 2157 tmp)) { 2158 int64_t breg_offset = opcodes.GetSLEB128(&offset); 2159 tmp.ResolveValue(exe_ctx) += (uint64_t)breg_offset; 2160 tmp.ClearContext(); 2161 stack.push_back(tmp); 2162 stack.back().SetValueType(Value::ValueType::LoadAddress); 2163 } else 2164 return false; 2165 } break; 2166 2167 case DW_OP_fbreg: 2168 if (exe_ctx) { 2169 if (frame) { 2170 Scalar value; 2171 if (frame->GetFrameBaseValue(value, error_ptr)) { 2172 int64_t fbreg_offset = opcodes.GetSLEB128(&offset); 2173 value += fbreg_offset; 2174 stack.push_back(value); 2175 stack.back().SetValueType(Value::ValueType::LoadAddress); 2176 } else 2177 return false; 2178 } else { 2179 if (error_ptr) 2180 error_ptr->SetErrorString( 2181 "Invalid stack frame in context for DW_OP_fbreg opcode."); 2182 return false; 2183 } 2184 } else { 2185 if (error_ptr) 2186 error_ptr->SetErrorString( 2187 "NULL execution context for DW_OP_fbreg.\n"); 2188 return false; 2189 } 2190 2191 break; 2192 2193 // OPCODE: DW_OP_nop 2194 // OPERANDS: none 2195 // DESCRIPTION: A place holder. It has no effect on the location stack 2196 // or any of its values. 2197 case DW_OP_nop: 2198 break; 2199 2200 // OPCODE: DW_OP_piece 2201 // OPERANDS: 1 2202 // ULEB128: byte size of the piece 2203 // DESCRIPTION: The operand describes the size in bytes of the piece of 2204 // the object referenced by the DWARF expression whose result is at the top 2205 // of the stack. If the piece is located in a register, but does not occupy 2206 // the entire register, the placement of the piece within that register is 2207 // defined by the ABI. 2208 // 2209 // Many compilers store a single variable in sets of registers, or store a 2210 // variable partially in memory and partially in registers. DW_OP_piece 2211 // provides a way of describing how large a part of a variable a particular 2212 // DWARF expression refers to. 2213 case DW_OP_piece: { 2214 LocationDescriptionKind piece_locdesc = dwarf4_location_description_kind; 2215 // Reset for the next piece. 2216 dwarf4_location_description_kind = Memory; 2217 2218 const uint64_t piece_byte_size = opcodes.GetULEB128(&offset); 2219 2220 if (piece_byte_size > 0) { 2221 Value curr_piece; 2222 2223 if (stack.empty()) { 2224 UpdateValueTypeFromLocationDescription( 2225 log, dwarf_cu, LocationDescriptionKind::Empty); 2226 // In a multi-piece expression, this means that the current piece is 2227 // not available. Fill with zeros for now by resizing the data and 2228 // appending it 2229 curr_piece.ResizeData(piece_byte_size); 2230 // Note that "0" is not a correct value for the unknown bits. 2231 // It would be better to also return a mask of valid bits together 2232 // with the expression result, so the debugger can print missing 2233 // members as "<optimized out>" or something. 2234 ::memset(curr_piece.GetBuffer().GetBytes(), 0, piece_byte_size); 2235 pieces.AppendDataToHostBuffer(curr_piece); 2236 } else { 2237 Status error; 2238 // Extract the current piece into "curr_piece" 2239 Value curr_piece_source_value(stack.back()); 2240 stack.pop_back(); 2241 UpdateValueTypeFromLocationDescription(log, dwarf_cu, piece_locdesc, 2242 &curr_piece_source_value); 2243 2244 const Value::ValueType curr_piece_source_value_type = 2245 curr_piece_source_value.GetValueType(); 2246 switch (curr_piece_source_value_type) { 2247 case Value::ValueType::Invalid: 2248 return false; 2249 case Value::ValueType::LoadAddress: 2250 if (process) { 2251 if (curr_piece.ResizeData(piece_byte_size) == piece_byte_size) { 2252 lldb::addr_t load_addr = 2253 curr_piece_source_value.GetScalar().ULongLong( 2254 LLDB_INVALID_ADDRESS); 2255 if (process->ReadMemory( 2256 load_addr, curr_piece.GetBuffer().GetBytes(), 2257 piece_byte_size, error) != piece_byte_size) { 2258 if (error_ptr) 2259 error_ptr->SetErrorStringWithFormat( 2260 "failed to read memory DW_OP_piece(%" PRIu64 2261 ") from 0x%" PRIx64, 2262 piece_byte_size, load_addr); 2263 return false; 2264 } 2265 } else { 2266 if (error_ptr) 2267 error_ptr->SetErrorStringWithFormat( 2268 "failed to resize the piece memory buffer for " 2269 "DW_OP_piece(%" PRIu64 ")", 2270 piece_byte_size); 2271 return false; 2272 } 2273 } 2274 break; 2275 2276 case Value::ValueType::FileAddress: 2277 case Value::ValueType::HostAddress: 2278 if (error_ptr) { 2279 lldb::addr_t addr = curr_piece_source_value.GetScalar().ULongLong( 2280 LLDB_INVALID_ADDRESS); 2281 error_ptr->SetErrorStringWithFormat( 2282 "failed to read memory DW_OP_piece(%" PRIu64 2283 ") from %s address 0x%" PRIx64, 2284 piece_byte_size, curr_piece_source_value.GetValueType() == 2285 Value::ValueType::FileAddress 2286 ? "file" 2287 : "host", 2288 addr); 2289 } 2290 return false; 2291 2292 case Value::ValueType::Scalar: { 2293 uint32_t bit_size = piece_byte_size * 8; 2294 uint32_t bit_offset = 0; 2295 Scalar &scalar = curr_piece_source_value.GetScalar(); 2296 if (!scalar.ExtractBitfield( 2297 bit_size, bit_offset)) { 2298 if (error_ptr) 2299 error_ptr->SetErrorStringWithFormat( 2300 "unable to extract %" PRIu64 " bytes from a %" PRIu64 2301 " byte scalar value.", 2302 piece_byte_size, 2303 (uint64_t)curr_piece_source_value.GetScalar() 2304 .GetByteSize()); 2305 return false; 2306 } 2307 // Create curr_piece with bit_size. By default Scalar 2308 // grows to the nearest host integer type. 2309 llvm::APInt fail_value(1, 0, false); 2310 llvm::APInt ap_int = scalar.UInt128(fail_value); 2311 assert(ap_int.getBitWidth() >= bit_size); 2312 llvm::ArrayRef<uint64_t> buf{ap_int.getRawData(), 2313 ap_int.getNumWords()}; 2314 curr_piece.GetScalar() = Scalar(llvm::APInt(bit_size, buf)); 2315 } break; 2316 } 2317 2318 // Check if this is the first piece? 2319 if (op_piece_offset == 0) { 2320 // This is the first piece, we should push it back onto the stack 2321 // so subsequent pieces will be able to access this piece and add 2322 // to it. 2323 if (pieces.AppendDataToHostBuffer(curr_piece) == 0) { 2324 if (error_ptr) 2325 error_ptr->SetErrorString("failed to append piece data"); 2326 return false; 2327 } 2328 } else { 2329 // If this is the second or later piece there should be a value on 2330 // the stack. 2331 if (pieces.GetBuffer().GetByteSize() != op_piece_offset) { 2332 if (error_ptr) 2333 error_ptr->SetErrorStringWithFormat( 2334 "DW_OP_piece for offset %" PRIu64 2335 " but top of stack is of size %" PRIu64, 2336 op_piece_offset, pieces.GetBuffer().GetByteSize()); 2337 return false; 2338 } 2339 2340 if (pieces.AppendDataToHostBuffer(curr_piece) == 0) { 2341 if (error_ptr) 2342 error_ptr->SetErrorString("failed to append piece data"); 2343 return false; 2344 } 2345 } 2346 } 2347 op_piece_offset += piece_byte_size; 2348 } 2349 } break; 2350 2351 case DW_OP_bit_piece: // 0x9d ULEB128 bit size, ULEB128 bit offset (DWARF3); 2352 if (stack.size() < 1) { 2353 UpdateValueTypeFromLocationDescription(log, dwarf_cu, 2354 LocationDescriptionKind::Empty); 2355 // Reset for the next piece. 2356 dwarf4_location_description_kind = Memory; 2357 if (error_ptr) 2358 error_ptr->SetErrorString( 2359 "Expression stack needs at least 1 item for DW_OP_bit_piece."); 2360 return false; 2361 } else { 2362 UpdateValueTypeFromLocationDescription( 2363 log, dwarf_cu, dwarf4_location_description_kind, &stack.back()); 2364 // Reset for the next piece. 2365 dwarf4_location_description_kind = Memory; 2366 const uint64_t piece_bit_size = opcodes.GetULEB128(&offset); 2367 const uint64_t piece_bit_offset = opcodes.GetULEB128(&offset); 2368 switch (stack.back().GetValueType()) { 2369 case Value::ValueType::Invalid: 2370 return false; 2371 case Value::ValueType::Scalar: { 2372 if (!stack.back().GetScalar().ExtractBitfield(piece_bit_size, 2373 piece_bit_offset)) { 2374 if (error_ptr) 2375 error_ptr->SetErrorStringWithFormat( 2376 "unable to extract %" PRIu64 " bit value with %" PRIu64 2377 " bit offset from a %" PRIu64 " bit scalar value.", 2378 piece_bit_size, piece_bit_offset, 2379 (uint64_t)(stack.back().GetScalar().GetByteSize() * 8)); 2380 return false; 2381 } 2382 } break; 2383 2384 case Value::ValueType::FileAddress: 2385 case Value::ValueType::LoadAddress: 2386 case Value::ValueType::HostAddress: 2387 if (error_ptr) { 2388 error_ptr->SetErrorStringWithFormat( 2389 "unable to extract DW_OP_bit_piece(bit_size = %" PRIu64 2390 ", bit_offset = %" PRIu64 ") from an address value.", 2391 piece_bit_size, piece_bit_offset); 2392 } 2393 return false; 2394 } 2395 } 2396 break; 2397 2398 // OPCODE: DW_OP_implicit_value 2399 // OPERANDS: 2 2400 // ULEB128 size of the value block in bytes 2401 // uint8_t* block bytes encoding value in target's memory 2402 // representation 2403 // DESCRIPTION: Value is immediately stored in block in the debug info with 2404 // the memory representation of the target. 2405 case DW_OP_implicit_value: { 2406 dwarf4_location_description_kind = Implicit; 2407 2408 const uint32_t len = opcodes.GetULEB128(&offset); 2409 const void *data = opcodes.GetData(&offset, len); 2410 2411 if (!data) { 2412 LLDB_LOG(log, "Evaluate_DW_OP_implicit_value: could not be read data"); 2413 LLDB_ERRORF(error_ptr, "Could not evaluate %s.", 2414 DW_OP_value_to_name(op)); 2415 return false; 2416 } 2417 2418 Value result(data, len); 2419 stack.push_back(result); 2420 break; 2421 } 2422 2423 case DW_OP_implicit_pointer: { 2424 dwarf4_location_description_kind = Implicit; 2425 LLDB_ERRORF(error_ptr, "Could not evaluate %s.", DW_OP_value_to_name(op)); 2426 return false; 2427 } 2428 2429 // OPCODE: DW_OP_push_object_address 2430 // OPERANDS: none 2431 // DESCRIPTION: Pushes the address of the object currently being 2432 // evaluated as part of evaluation of a user presented expression. This 2433 // object may correspond to an independent variable described by its own 2434 // DIE or it may be a component of an array, structure, or class whose 2435 // address has been dynamically determined by an earlier step during user 2436 // expression evaluation. 2437 case DW_OP_push_object_address: 2438 if (object_address_ptr) 2439 stack.push_back(*object_address_ptr); 2440 else { 2441 if (error_ptr) 2442 error_ptr->SetErrorString("DW_OP_push_object_address used without " 2443 "specifying an object address"); 2444 return false; 2445 } 2446 break; 2447 2448 // OPCODE: DW_OP_call2 2449 // OPERANDS: 2450 // uint16_t compile unit relative offset of a DIE 2451 // DESCRIPTION: Performs subroutine calls during evaluation 2452 // of a DWARF expression. The operand is the 2-byte unsigned offset of a 2453 // debugging information entry in the current compilation unit. 2454 // 2455 // Operand interpretation is exactly like that for DW_FORM_ref2. 2456 // 2457 // This operation transfers control of DWARF expression evaluation to the 2458 // DW_AT_location attribute of the referenced DIE. If there is no such 2459 // attribute, then there is no effect. Execution of the DWARF expression of 2460 // a DW_AT_location attribute may add to and/or remove from values on the 2461 // stack. Execution returns to the point following the call when the end of 2462 // the attribute is reached. Values on the stack at the time of the call 2463 // may be used as parameters by the called expression and values left on 2464 // the stack by the called expression may be used as return values by prior 2465 // agreement between the calling and called expressions. 2466 case DW_OP_call2: 2467 if (error_ptr) 2468 error_ptr->SetErrorString("Unimplemented opcode DW_OP_call2."); 2469 return false; 2470 // OPCODE: DW_OP_call4 2471 // OPERANDS: 1 2472 // uint32_t compile unit relative offset of a DIE 2473 // DESCRIPTION: Performs a subroutine call during evaluation of a DWARF 2474 // expression. For DW_OP_call4, the operand is a 4-byte unsigned offset of 2475 // a debugging information entry in the current compilation unit. 2476 // 2477 // Operand interpretation DW_OP_call4 is exactly like that for 2478 // DW_FORM_ref4. 2479 // 2480 // This operation transfers control of DWARF expression evaluation to the 2481 // DW_AT_location attribute of the referenced DIE. If there is no such 2482 // attribute, then there is no effect. Execution of the DWARF expression of 2483 // a DW_AT_location attribute may add to and/or remove from values on the 2484 // stack. Execution returns to the point following the call when the end of 2485 // the attribute is reached. Values on the stack at the time of the call 2486 // may be used as parameters by the called expression and values left on 2487 // the stack by the called expression may be used as return values by prior 2488 // agreement between the calling and called expressions. 2489 case DW_OP_call4: 2490 if (error_ptr) 2491 error_ptr->SetErrorString("Unimplemented opcode DW_OP_call4."); 2492 return false; 2493 2494 // OPCODE: DW_OP_stack_value 2495 // OPERANDS: None 2496 // DESCRIPTION: Specifies that the object does not exist in memory but 2497 // rather is a constant value. The value from the top of the stack is the 2498 // value to be used. This is the actual object value and not the location. 2499 case DW_OP_stack_value: 2500 dwarf4_location_description_kind = Implicit; 2501 if (stack.empty()) { 2502 if (error_ptr) 2503 error_ptr->SetErrorString( 2504 "Expression stack needs at least 1 item for DW_OP_stack_value."); 2505 return false; 2506 } 2507 stack.back().SetValueType(Value::ValueType::Scalar); 2508 break; 2509 2510 // OPCODE: DW_OP_convert 2511 // OPERANDS: 1 2512 // A ULEB128 that is either a DIE offset of a 2513 // DW_TAG_base_type or 0 for the generic (pointer-sized) type. 2514 // 2515 // DESCRIPTION: Pop the top stack element, convert it to a 2516 // different type, and push the result. 2517 case DW_OP_convert: { 2518 if (stack.size() < 1) { 2519 if (error_ptr) 2520 error_ptr->SetErrorString( 2521 "Expression stack needs at least 1 item for DW_OP_convert."); 2522 return false; 2523 } 2524 const uint64_t die_offset = opcodes.GetULEB128(&offset); 2525 uint64_t bit_size; 2526 bool sign; 2527 if (die_offset == 0) { 2528 // The generic type has the size of an address on the target 2529 // machine and an unspecified signedness. Scalar has no 2530 // "unspecified signedness", so we use unsigned types. 2531 if (!module_sp) { 2532 if (error_ptr) 2533 error_ptr->SetErrorString("No module"); 2534 return false; 2535 } 2536 sign = false; 2537 bit_size = module_sp->GetArchitecture().GetAddressByteSize() * 8; 2538 if (!bit_size) { 2539 if (error_ptr) 2540 error_ptr->SetErrorString("unspecified architecture"); 2541 return false; 2542 } 2543 } else { 2544 // Retrieve the type DIE that the value is being converted to. 2545 // FIXME: the constness has annoying ripple effects. 2546 DWARFDIE die = const_cast<DWARFUnit *>(dwarf_cu)->GetDIE(die_offset); 2547 if (!die) { 2548 if (error_ptr) 2549 error_ptr->SetErrorString("Cannot resolve DW_OP_convert type DIE"); 2550 return false; 2551 } 2552 uint64_t encoding = 2553 die.GetAttributeValueAsUnsigned(DW_AT_encoding, DW_ATE_hi_user); 2554 bit_size = die.GetAttributeValueAsUnsigned(DW_AT_byte_size, 0) * 8; 2555 if (!bit_size) 2556 bit_size = die.GetAttributeValueAsUnsigned(DW_AT_bit_size, 0); 2557 if (!bit_size) { 2558 if (error_ptr) 2559 error_ptr->SetErrorString("Unsupported type size in DW_OP_convert"); 2560 return false; 2561 } 2562 switch (encoding) { 2563 case DW_ATE_signed: 2564 case DW_ATE_signed_char: 2565 sign = true; 2566 break; 2567 case DW_ATE_unsigned: 2568 case DW_ATE_unsigned_char: 2569 sign = false; 2570 break; 2571 default: 2572 if (error_ptr) 2573 error_ptr->SetErrorString("Unsupported encoding in DW_OP_convert"); 2574 return false; 2575 } 2576 } 2577 Scalar &top = stack.back().ResolveValue(exe_ctx); 2578 top.TruncOrExtendTo(bit_size, sign); 2579 break; 2580 } 2581 2582 // OPCODE: DW_OP_call_frame_cfa 2583 // OPERANDS: None 2584 // DESCRIPTION: Specifies a DWARF expression that pushes the value of 2585 // the canonical frame address consistent with the call frame information 2586 // located in .debug_frame (or in the FDEs of the eh_frame section). 2587 case DW_OP_call_frame_cfa: 2588 if (frame) { 2589 // Note that we don't have to parse FDEs because this DWARF expression 2590 // is commonly evaluated with a valid stack frame. 2591 StackID id = frame->GetStackID(); 2592 addr_t cfa = id.GetCallFrameAddress(); 2593 if (cfa != LLDB_INVALID_ADDRESS) { 2594 stack.push_back(Scalar(cfa)); 2595 stack.back().SetValueType(Value::ValueType::LoadAddress); 2596 } else if (error_ptr) 2597 error_ptr->SetErrorString("Stack frame does not include a canonical " 2598 "frame address for DW_OP_call_frame_cfa " 2599 "opcode."); 2600 } else { 2601 if (error_ptr) 2602 error_ptr->SetErrorString("Invalid stack frame in context for " 2603 "DW_OP_call_frame_cfa opcode."); 2604 return false; 2605 } 2606 break; 2607 2608 // OPCODE: DW_OP_form_tls_address (or the old pre-DWARFv3 vendor extension 2609 // opcode, DW_OP_GNU_push_tls_address) 2610 // OPERANDS: none 2611 // DESCRIPTION: Pops a TLS offset from the stack, converts it to 2612 // an address in the current thread's thread-local storage block, and 2613 // pushes it on the stack. 2614 case DW_OP_form_tls_address: 2615 case DW_OP_GNU_push_tls_address: { 2616 if (stack.size() < 1) { 2617 if (error_ptr) { 2618 if (op == DW_OP_form_tls_address) 2619 error_ptr->SetErrorString( 2620 "DW_OP_form_tls_address needs an argument."); 2621 else 2622 error_ptr->SetErrorString( 2623 "DW_OP_GNU_push_tls_address needs an argument."); 2624 } 2625 return false; 2626 } 2627 2628 if (!exe_ctx || !module_sp) { 2629 if (error_ptr) 2630 error_ptr->SetErrorString("No context to evaluate TLS within."); 2631 return false; 2632 } 2633 2634 Thread *thread = exe_ctx->GetThreadPtr(); 2635 if (!thread) { 2636 if (error_ptr) 2637 error_ptr->SetErrorString("No thread to evaluate TLS within."); 2638 return false; 2639 } 2640 2641 // Lookup the TLS block address for this thread and module. 2642 const addr_t tls_file_addr = 2643 stack.back().GetScalar().ULongLong(LLDB_INVALID_ADDRESS); 2644 const addr_t tls_load_addr = 2645 thread->GetThreadLocalData(module_sp, tls_file_addr); 2646 2647 if (tls_load_addr == LLDB_INVALID_ADDRESS) { 2648 if (error_ptr) 2649 error_ptr->SetErrorString( 2650 "No TLS data currently exists for this thread."); 2651 return false; 2652 } 2653 2654 stack.back().GetScalar() = tls_load_addr; 2655 stack.back().SetValueType(Value::ValueType::LoadAddress); 2656 } break; 2657 2658 // OPCODE: DW_OP_addrx (DW_OP_GNU_addr_index is the legacy name.) 2659 // OPERANDS: 1 2660 // ULEB128: index to the .debug_addr section 2661 // DESCRIPTION: Pushes an address to the stack from the .debug_addr 2662 // section with the base address specified by the DW_AT_addr_base attribute 2663 // and the 0 based index is the ULEB128 encoded index. 2664 case DW_OP_addrx: 2665 case DW_OP_GNU_addr_index: { 2666 if (!dwarf_cu) { 2667 if (error_ptr) 2668 error_ptr->SetErrorString("DW_OP_GNU_addr_index found without a " 2669 "compile unit being specified"); 2670 return false; 2671 } 2672 uint64_t index = opcodes.GetULEB128(&offset); 2673 lldb::addr_t value = ReadAddressFromDebugAddrSection(dwarf_cu, index); 2674 stack.push_back(Scalar(value)); 2675 stack.back().SetValueType(Value::ValueType::FileAddress); 2676 } break; 2677 2678 // OPCODE: DW_OP_GNU_const_index 2679 // OPERANDS: 1 2680 // ULEB128: index to the .debug_addr section 2681 // DESCRIPTION: Pushes an constant with the size of a machine address to 2682 // the stack from the .debug_addr section with the base address specified 2683 // by the DW_AT_addr_base attribute and the 0 based index is the ULEB128 2684 // encoded index. 2685 case DW_OP_GNU_const_index: { 2686 if (!dwarf_cu) { 2687 if (error_ptr) 2688 error_ptr->SetErrorString("DW_OP_GNU_const_index found without a " 2689 "compile unit being specified"); 2690 return false; 2691 } 2692 uint64_t index = opcodes.GetULEB128(&offset); 2693 lldb::addr_t value = ReadAddressFromDebugAddrSection(dwarf_cu, index); 2694 stack.push_back(Scalar(value)); 2695 } break; 2696 2697 case DW_OP_GNU_entry_value: 2698 case DW_OP_entry_value: { 2699 if (!Evaluate_DW_OP_entry_value(stack, exe_ctx, reg_ctx, opcodes, offset, 2700 error_ptr, log)) { 2701 LLDB_ERRORF(error_ptr, "Could not evaluate %s.", 2702 DW_OP_value_to_name(op)); 2703 return false; 2704 } 2705 break; 2706 } 2707 2708 default: 2709 if (error_ptr) 2710 error_ptr->SetErrorStringWithFormatv( 2711 "Unhandled opcode {0} in DWARFExpression", LocationAtom(op)); 2712 return false; 2713 } 2714 } 2715 2716 if (stack.empty()) { 2717 // Nothing on the stack, check if we created a piece value from DW_OP_piece 2718 // or DW_OP_bit_piece opcodes 2719 if (pieces.GetBuffer().GetByteSize()) { 2720 result = pieces; 2721 return true; 2722 } 2723 if (error_ptr) 2724 error_ptr->SetErrorString("Stack empty after evaluation."); 2725 return false; 2726 } 2727 2728 UpdateValueTypeFromLocationDescription( 2729 log, dwarf_cu, dwarf4_location_description_kind, &stack.back()); 2730 2731 if (log && log->GetVerbose()) { 2732 size_t count = stack.size(); 2733 LLDB_LOGF(log, 2734 "Stack after operation has %" PRIu64 " values:", (uint64_t)count); 2735 for (size_t i = 0; i < count; ++i) { 2736 StreamString new_value; 2737 new_value.Printf("[%" PRIu64 "]", (uint64_t)i); 2738 stack[i].Dump(&new_value); 2739 LLDB_LOGF(log, " %s", new_value.GetData()); 2740 } 2741 } 2742 result = stack.back(); 2743 return true; // Return true on success 2744 } 2745 2746 static DataExtractor ToDataExtractor(const llvm::DWARFLocationExpression &loc, 2747 ByteOrder byte_order, uint32_t addr_size) { 2748 auto buffer_sp = 2749 std::make_shared<DataBufferHeap>(loc.Expr.data(), loc.Expr.size()); 2750 return DataExtractor(buffer_sp, byte_order, addr_size); 2751 } 2752 2753 bool DWARFExpression::DumpLocations(Stream *s, lldb::DescriptionLevel level, 2754 addr_t load_function_start, addr_t addr, 2755 ABI *abi) { 2756 if (!IsLocationList()) { 2757 DumpLocation(s, m_data, level, abi); 2758 return true; 2759 } 2760 bool dump_all = addr == LLDB_INVALID_ADDRESS; 2761 llvm::ListSeparator separator; 2762 auto callback = [&](llvm::DWARFLocationExpression loc) -> bool { 2763 if (loc.Range && 2764 (dump_all || (loc.Range->LowPC <= addr && addr < loc.Range->HighPC))) { 2765 uint32_t addr_size = m_data.GetAddressByteSize(); 2766 DataExtractor data = ToDataExtractor(loc, m_data.GetByteOrder(), 2767 m_data.GetAddressByteSize()); 2768 s->AsRawOstream() << separator; 2769 s->PutCString("["); 2770 s->AsRawOstream() << llvm::format_hex(loc.Range->LowPC, 2771 2 + 2 * addr_size); 2772 s->PutCString(", "); 2773 s->AsRawOstream() << llvm::format_hex(loc.Range->HighPC, 2774 2 + 2 * addr_size); 2775 s->PutCString(") -> "); 2776 DumpLocation(s, data, level, abi); 2777 return dump_all; 2778 } 2779 return true; 2780 }; 2781 if (!GetLocationExpressions(load_function_start, callback)) 2782 return false; 2783 return true; 2784 } 2785 2786 bool DWARFExpression::GetLocationExpressions( 2787 addr_t load_function_start, 2788 llvm::function_ref<bool(llvm::DWARFLocationExpression)> callback) const { 2789 if (load_function_start == LLDB_INVALID_ADDRESS) 2790 return false; 2791 2792 Log *log = GetLog(LLDBLog::Expressions); 2793 2794 std::unique_ptr<llvm::DWARFLocationTable> loctable_up = 2795 m_dwarf_cu->GetLocationTable(m_data); 2796 2797 uint64_t offset = 0; 2798 auto lookup_addr = 2799 [&](uint32_t index) -> llvm::Optional<llvm::object::SectionedAddress> { 2800 addr_t address = ReadAddressFromDebugAddrSection(m_dwarf_cu, index); 2801 if (address == LLDB_INVALID_ADDRESS) 2802 return llvm::None; 2803 return llvm::object::SectionedAddress{address}; 2804 }; 2805 auto process_list = [&](llvm::Expected<llvm::DWARFLocationExpression> loc) { 2806 if (!loc) { 2807 LLDB_LOG_ERROR(log, loc.takeError(), "{0}"); 2808 return true; 2809 } 2810 if (loc->Range) { 2811 // This relocates low_pc and high_pc by adding the difference between the 2812 // function file address, and the actual address it is loaded in memory. 2813 addr_t slide = load_function_start - m_loclist_addresses->func_file_addr; 2814 loc->Range->LowPC += slide; 2815 loc->Range->HighPC += slide; 2816 } 2817 return callback(*loc); 2818 }; 2819 llvm::Error error = loctable_up->visitAbsoluteLocationList( 2820 offset, llvm::object::SectionedAddress{m_loclist_addresses->cu_file_addr}, 2821 lookup_addr, process_list); 2822 if (error) { 2823 LLDB_LOG_ERROR(log, std::move(error), "{0}"); 2824 return false; 2825 } 2826 return true; 2827 } 2828 2829 llvm::Optional<DataExtractor> 2830 DWARFExpression::GetLocationExpression(addr_t load_function_start, 2831 addr_t addr) const { 2832 llvm::Optional<DataExtractor> data; 2833 auto callback = [&](llvm::DWARFLocationExpression loc) { 2834 if (loc.Range && loc.Range->LowPC <= addr && addr < loc.Range->HighPC) { 2835 data = ToDataExtractor(loc, m_data.GetByteOrder(), 2836 m_data.GetAddressByteSize()); 2837 } 2838 return !data; 2839 }; 2840 GetLocationExpressions(load_function_start, callback); 2841 return data; 2842 } 2843 2844 bool DWARFExpression::MatchesOperand(StackFrame &frame, 2845 const Instruction::Operand &operand) { 2846 using namespace OperandMatchers; 2847 2848 RegisterContextSP reg_ctx_sp = frame.GetRegisterContext(); 2849 if (!reg_ctx_sp) { 2850 return false; 2851 } 2852 2853 DataExtractor opcodes; 2854 if (IsLocationList()) { 2855 SymbolContext sc = frame.GetSymbolContext(eSymbolContextFunction); 2856 if (!sc.function) 2857 return false; 2858 2859 addr_t load_function_start = 2860 sc.function->GetAddressRange().GetBaseAddress().GetFileAddress(); 2861 if (load_function_start == LLDB_INVALID_ADDRESS) 2862 return false; 2863 2864 addr_t pc = frame.GetFrameCodeAddressForSymbolication().GetLoadAddress( 2865 frame.CalculateTarget().get()); 2866 2867 if (llvm::Optional<DataExtractor> expr = 2868 GetLocationExpression(load_function_start, pc)) 2869 opcodes = std::move(*expr); 2870 else 2871 return false; 2872 } else 2873 opcodes = m_data; 2874 2875 2876 lldb::offset_t op_offset = 0; 2877 uint8_t opcode = opcodes.GetU8(&op_offset); 2878 2879 if (opcode == DW_OP_fbreg) { 2880 int64_t offset = opcodes.GetSLEB128(&op_offset); 2881 2882 DWARFExpression *fb_expr = frame.GetFrameBaseExpression(nullptr); 2883 if (!fb_expr) { 2884 return false; 2885 } 2886 2887 auto recurse = [&frame, fb_expr](const Instruction::Operand &child) { 2888 return fb_expr->MatchesOperand(frame, child); 2889 }; 2890 2891 if (!offset && 2892 MatchUnaryOp(MatchOpType(Instruction::Operand::Type::Dereference), 2893 recurse)(operand)) { 2894 return true; 2895 } 2896 2897 return MatchUnaryOp( 2898 MatchOpType(Instruction::Operand::Type::Dereference), 2899 MatchBinaryOp(MatchOpType(Instruction::Operand::Type::Sum), 2900 MatchImmOp(offset), recurse))(operand); 2901 } 2902 2903 bool dereference = false; 2904 const RegisterInfo *reg = nullptr; 2905 int64_t offset = 0; 2906 2907 if (opcode >= DW_OP_reg0 && opcode <= DW_OP_reg31) { 2908 reg = reg_ctx_sp->GetRegisterInfo(m_reg_kind, opcode - DW_OP_reg0); 2909 } else if (opcode >= DW_OP_breg0 && opcode <= DW_OP_breg31) { 2910 offset = opcodes.GetSLEB128(&op_offset); 2911 reg = reg_ctx_sp->GetRegisterInfo(m_reg_kind, opcode - DW_OP_breg0); 2912 } else if (opcode == DW_OP_regx) { 2913 uint32_t reg_num = static_cast<uint32_t>(opcodes.GetULEB128(&op_offset)); 2914 reg = reg_ctx_sp->GetRegisterInfo(m_reg_kind, reg_num); 2915 } else if (opcode == DW_OP_bregx) { 2916 uint32_t reg_num = static_cast<uint32_t>(opcodes.GetULEB128(&op_offset)); 2917 offset = opcodes.GetSLEB128(&op_offset); 2918 reg = reg_ctx_sp->GetRegisterInfo(m_reg_kind, reg_num); 2919 } else { 2920 return false; 2921 } 2922 2923 if (!reg) { 2924 return false; 2925 } 2926 2927 if (dereference) { 2928 if (!offset && 2929 MatchUnaryOp(MatchOpType(Instruction::Operand::Type::Dereference), 2930 MatchRegOp(*reg))(operand)) { 2931 return true; 2932 } 2933 2934 return MatchUnaryOp( 2935 MatchOpType(Instruction::Operand::Type::Dereference), 2936 MatchBinaryOp(MatchOpType(Instruction::Operand::Type::Sum), 2937 MatchRegOp(*reg), 2938 MatchImmOp(offset)))(operand); 2939 } else { 2940 return MatchRegOp(*reg)(operand); 2941 } 2942 } 2943