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 <optional> 14 #include <vector> 15 16 #include "lldb/Core/Module.h" 17 #include "lldb/Core/Value.h" 18 #include "lldb/Core/dwarf.h" 19 #include "lldb/Utility/DataEncoder.h" 20 #include "lldb/Utility/LLDBLog.h" 21 #include "lldb/Utility/Log.h" 22 #include "lldb/Utility/RegisterValue.h" 23 #include "lldb/Utility/Scalar.h" 24 #include "lldb/Utility/StreamString.h" 25 #include "lldb/Utility/VMRange.h" 26 27 #include "lldb/Host/Host.h" 28 #include "lldb/Utility/Endian.h" 29 30 #include "lldb/Symbol/Function.h" 31 32 #include "lldb/Target/ABI.h" 33 #include "lldb/Target/ExecutionContext.h" 34 #include "lldb/Target/Process.h" 35 #include "lldb/Target/RegisterContext.h" 36 #include "lldb/Target/StackFrame.h" 37 #include "lldb/Target/StackID.h" 38 #include "lldb/Target/Target.h" 39 #include "lldb/Target/Thread.h" 40 #include "llvm/DebugInfo/DWARF/DWARFDebugLoc.h" 41 #include "llvm/DebugInfo/DWARF/DWARFExpression.h" 42 43 #include "Plugins/SymbolFile/DWARF/DWARFUnit.h" 44 45 using namespace lldb; 46 using namespace lldb_private; 47 using namespace lldb_private::dwarf; 48 using namespace lldb_private::plugin::dwarf; 49 50 // DWARFExpression constructor 51 DWARFExpression::DWARFExpression() : m_data() {} 52 53 DWARFExpression::DWARFExpression(const DataExtractor &data) : m_data(data) {} 54 55 // Destructor 56 DWARFExpression::~DWARFExpression() = default; 57 58 bool DWARFExpression::IsValid() const { return m_data.GetByteSize() > 0; } 59 60 void DWARFExpression::UpdateValue(uint64_t const_value, 61 lldb::offset_t const_value_byte_size, 62 uint8_t addr_byte_size) { 63 if (!const_value_byte_size) 64 return; 65 66 m_data.SetData( 67 DataBufferSP(new DataBufferHeap(&const_value, const_value_byte_size))); 68 m_data.SetByteOrder(endian::InlHostByteOrder()); 69 m_data.SetAddressByteSize(addr_byte_size); 70 } 71 72 void DWARFExpression::DumpLocation(Stream *s, lldb::DescriptionLevel level, 73 ABI *abi) const { 74 auto *MCRegInfo = abi ? &abi->GetMCRegisterInfo() : nullptr; 75 auto GetRegName = [&MCRegInfo](uint64_t DwarfRegNum, 76 bool IsEH) -> llvm::StringRef { 77 if (!MCRegInfo) 78 return {}; 79 if (std::optional<unsigned> LLVMRegNum = 80 MCRegInfo->getLLVMRegNum(DwarfRegNum, IsEH)) 81 if (const char *RegName = MCRegInfo->getName(*LLVMRegNum)) 82 return llvm::StringRef(RegName); 83 return {}; 84 }; 85 llvm::DIDumpOptions DumpOpts; 86 DumpOpts.GetNameForDWARFReg = GetRegName; 87 llvm::DWARFExpression(m_data.GetAsLLVM(), m_data.GetAddressByteSize()) 88 .print(s->AsRawOstream(), DumpOpts, nullptr); 89 } 90 91 RegisterKind DWARFExpression::GetRegisterKind() const { return m_reg_kind; } 92 93 void DWARFExpression::SetRegisterKind(RegisterKind reg_kind) { 94 m_reg_kind = reg_kind; 95 } 96 97 static llvm::Error ReadRegisterValueAsScalar(RegisterContext *reg_ctx, 98 lldb::RegisterKind reg_kind, 99 uint32_t reg_num, Value &value) { 100 if (reg_ctx == nullptr) 101 return llvm::createStringError("no register context in frame"); 102 103 const uint32_t native_reg = 104 reg_ctx->ConvertRegisterKindToRegisterNumber(reg_kind, reg_num); 105 if (native_reg == LLDB_INVALID_REGNUM) 106 return llvm::createStringError( 107 "unable to convert register kind=%u reg_num=%u to a native " 108 "register number", 109 reg_kind, reg_num); 110 111 const RegisterInfo *reg_info = reg_ctx->GetRegisterInfoAtIndex(native_reg); 112 RegisterValue reg_value; 113 if (reg_ctx->ReadRegister(reg_info, reg_value)) { 114 if (reg_value.GetScalarValue(value.GetScalar())) { 115 value.SetValueType(Value::ValueType::Scalar); 116 value.SetContext(Value::ContextType::RegisterInfo, 117 const_cast<RegisterInfo *>(reg_info)); 118 return llvm::Error::success(); 119 } 120 121 // If we get this error, then we need to implement a value buffer in 122 // the dwarf expression evaluation function... 123 return llvm::createStringError( 124 "register %s can't be converted to a scalar value", reg_info->name); 125 } 126 127 return llvm::createStringError("register %s is not available", 128 reg_info->name); 129 } 130 131 /// Return the length in bytes of the set of operands for \p op. No guarantees 132 /// are made on the state of \p data after this call. 133 static lldb::offset_t GetOpcodeDataSize(const DataExtractor &data, 134 const lldb::offset_t data_offset, 135 const LocationAtom op, 136 const DWARFUnit *dwarf_cu) { 137 lldb::offset_t offset = data_offset; 138 switch (op) { 139 // Only used in LLVM metadata. 140 case DW_OP_LLVM_fragment: 141 case DW_OP_LLVM_convert: 142 case DW_OP_LLVM_tag_offset: 143 case DW_OP_LLVM_entry_value: 144 case DW_OP_LLVM_implicit_pointer: 145 case DW_OP_LLVM_arg: 146 case DW_OP_LLVM_extract_bits_sext: 147 case DW_OP_LLVM_extract_bits_zext: 148 break; 149 // Vendor extensions: 150 case DW_OP_HP_is_value: 151 case DW_OP_HP_fltconst4: 152 case DW_OP_HP_fltconst8: 153 case DW_OP_HP_mod_range: 154 case DW_OP_HP_unmod_range: 155 case DW_OP_HP_tls: 156 case DW_OP_INTEL_bit_piece: 157 case DW_OP_WASM_location: 158 case DW_OP_WASM_location_int: 159 case DW_OP_APPLE_uninit: 160 case DW_OP_PGI_omp_thread_num: 161 case DW_OP_hi_user: 162 break; 163 164 case DW_OP_addr: 165 case DW_OP_call_ref: // 0x9a 1 address sized offset of DIE (DWARF3) 166 return data.GetAddressByteSize(); 167 168 // Opcodes with no arguments 169 case DW_OP_deref: // 0x06 170 case DW_OP_dup: // 0x12 171 case DW_OP_drop: // 0x13 172 case DW_OP_over: // 0x14 173 case DW_OP_swap: // 0x16 174 case DW_OP_rot: // 0x17 175 case DW_OP_xderef: // 0x18 176 case DW_OP_abs: // 0x19 177 case DW_OP_and: // 0x1a 178 case DW_OP_div: // 0x1b 179 case DW_OP_minus: // 0x1c 180 case DW_OP_mod: // 0x1d 181 case DW_OP_mul: // 0x1e 182 case DW_OP_neg: // 0x1f 183 case DW_OP_not: // 0x20 184 case DW_OP_or: // 0x21 185 case DW_OP_plus: // 0x22 186 case DW_OP_shl: // 0x24 187 case DW_OP_shr: // 0x25 188 case DW_OP_shra: // 0x26 189 case DW_OP_xor: // 0x27 190 case DW_OP_eq: // 0x29 191 case DW_OP_ge: // 0x2a 192 case DW_OP_gt: // 0x2b 193 case DW_OP_le: // 0x2c 194 case DW_OP_lt: // 0x2d 195 case DW_OP_ne: // 0x2e 196 case DW_OP_lit0: // 0x30 197 case DW_OP_lit1: // 0x31 198 case DW_OP_lit2: // 0x32 199 case DW_OP_lit3: // 0x33 200 case DW_OP_lit4: // 0x34 201 case DW_OP_lit5: // 0x35 202 case DW_OP_lit6: // 0x36 203 case DW_OP_lit7: // 0x37 204 case DW_OP_lit8: // 0x38 205 case DW_OP_lit9: // 0x39 206 case DW_OP_lit10: // 0x3A 207 case DW_OP_lit11: // 0x3B 208 case DW_OP_lit12: // 0x3C 209 case DW_OP_lit13: // 0x3D 210 case DW_OP_lit14: // 0x3E 211 case DW_OP_lit15: // 0x3F 212 case DW_OP_lit16: // 0x40 213 case DW_OP_lit17: // 0x41 214 case DW_OP_lit18: // 0x42 215 case DW_OP_lit19: // 0x43 216 case DW_OP_lit20: // 0x44 217 case DW_OP_lit21: // 0x45 218 case DW_OP_lit22: // 0x46 219 case DW_OP_lit23: // 0x47 220 case DW_OP_lit24: // 0x48 221 case DW_OP_lit25: // 0x49 222 case DW_OP_lit26: // 0x4A 223 case DW_OP_lit27: // 0x4B 224 case DW_OP_lit28: // 0x4C 225 case DW_OP_lit29: // 0x4D 226 case DW_OP_lit30: // 0x4E 227 case DW_OP_lit31: // 0x4f 228 case DW_OP_reg0: // 0x50 229 case DW_OP_reg1: // 0x51 230 case DW_OP_reg2: // 0x52 231 case DW_OP_reg3: // 0x53 232 case DW_OP_reg4: // 0x54 233 case DW_OP_reg5: // 0x55 234 case DW_OP_reg6: // 0x56 235 case DW_OP_reg7: // 0x57 236 case DW_OP_reg8: // 0x58 237 case DW_OP_reg9: // 0x59 238 case DW_OP_reg10: // 0x5A 239 case DW_OP_reg11: // 0x5B 240 case DW_OP_reg12: // 0x5C 241 case DW_OP_reg13: // 0x5D 242 case DW_OP_reg14: // 0x5E 243 case DW_OP_reg15: // 0x5F 244 case DW_OP_reg16: // 0x60 245 case DW_OP_reg17: // 0x61 246 case DW_OP_reg18: // 0x62 247 case DW_OP_reg19: // 0x63 248 case DW_OP_reg20: // 0x64 249 case DW_OP_reg21: // 0x65 250 case DW_OP_reg22: // 0x66 251 case DW_OP_reg23: // 0x67 252 case DW_OP_reg24: // 0x68 253 case DW_OP_reg25: // 0x69 254 case DW_OP_reg26: // 0x6A 255 case DW_OP_reg27: // 0x6B 256 case DW_OP_reg28: // 0x6C 257 case DW_OP_reg29: // 0x6D 258 case DW_OP_reg30: // 0x6E 259 case DW_OP_reg31: // 0x6F 260 case DW_OP_nop: // 0x96 261 case DW_OP_push_object_address: // 0x97 DWARF3 262 case DW_OP_form_tls_address: // 0x9b DWARF3 263 case DW_OP_call_frame_cfa: // 0x9c DWARF3 264 case DW_OP_stack_value: // 0x9f DWARF4 265 case DW_OP_GNU_push_tls_address: // 0xe0 GNU extension 266 return 0; 267 268 // Opcodes with a single 1 byte arguments 269 case DW_OP_const1u: // 0x08 1 1-byte constant 270 case DW_OP_const1s: // 0x09 1 1-byte constant 271 case DW_OP_pick: // 0x15 1 1-byte stack index 272 case DW_OP_deref_size: // 0x94 1 1-byte size of data retrieved 273 case DW_OP_xderef_size: // 0x95 1 1-byte size of data retrieved 274 case DW_OP_deref_type: // 0xa6 1 1-byte constant 275 return 1; 276 277 // Opcodes with a single 2 byte arguments 278 case DW_OP_const2u: // 0x0a 1 2-byte constant 279 case DW_OP_const2s: // 0x0b 1 2-byte constant 280 case DW_OP_skip: // 0x2f 1 signed 2-byte constant 281 case DW_OP_bra: // 0x28 1 signed 2-byte constant 282 case DW_OP_call2: // 0x98 1 2-byte offset of DIE (DWARF3) 283 return 2; 284 285 // Opcodes with a single 4 byte arguments 286 case DW_OP_const4u: // 0x0c 1 4-byte constant 287 case DW_OP_const4s: // 0x0d 1 4-byte constant 288 case DW_OP_call4: // 0x99 1 4-byte offset of DIE (DWARF3) 289 return 4; 290 291 // Opcodes with a single 8 byte arguments 292 case DW_OP_const8u: // 0x0e 1 8-byte constant 293 case DW_OP_const8s: // 0x0f 1 8-byte constant 294 return 8; 295 296 // All opcodes that have a single ULEB (signed or unsigned) argument 297 case DW_OP_constu: // 0x10 1 ULEB128 constant 298 case DW_OP_consts: // 0x11 1 SLEB128 constant 299 case DW_OP_plus_uconst: // 0x23 1 ULEB128 addend 300 case DW_OP_breg0: // 0x70 1 ULEB128 register 301 case DW_OP_breg1: // 0x71 1 ULEB128 register 302 case DW_OP_breg2: // 0x72 1 ULEB128 register 303 case DW_OP_breg3: // 0x73 1 ULEB128 register 304 case DW_OP_breg4: // 0x74 1 ULEB128 register 305 case DW_OP_breg5: // 0x75 1 ULEB128 register 306 case DW_OP_breg6: // 0x76 1 ULEB128 register 307 case DW_OP_breg7: // 0x77 1 ULEB128 register 308 case DW_OP_breg8: // 0x78 1 ULEB128 register 309 case DW_OP_breg9: // 0x79 1 ULEB128 register 310 case DW_OP_breg10: // 0x7a 1 ULEB128 register 311 case DW_OP_breg11: // 0x7b 1 ULEB128 register 312 case DW_OP_breg12: // 0x7c 1 ULEB128 register 313 case DW_OP_breg13: // 0x7d 1 ULEB128 register 314 case DW_OP_breg14: // 0x7e 1 ULEB128 register 315 case DW_OP_breg15: // 0x7f 1 ULEB128 register 316 case DW_OP_breg16: // 0x80 1 ULEB128 register 317 case DW_OP_breg17: // 0x81 1 ULEB128 register 318 case DW_OP_breg18: // 0x82 1 ULEB128 register 319 case DW_OP_breg19: // 0x83 1 ULEB128 register 320 case DW_OP_breg20: // 0x84 1 ULEB128 register 321 case DW_OP_breg21: // 0x85 1 ULEB128 register 322 case DW_OP_breg22: // 0x86 1 ULEB128 register 323 case DW_OP_breg23: // 0x87 1 ULEB128 register 324 case DW_OP_breg24: // 0x88 1 ULEB128 register 325 case DW_OP_breg25: // 0x89 1 ULEB128 register 326 case DW_OP_breg26: // 0x8a 1 ULEB128 register 327 case DW_OP_breg27: // 0x8b 1 ULEB128 register 328 case DW_OP_breg28: // 0x8c 1 ULEB128 register 329 case DW_OP_breg29: // 0x8d 1 ULEB128 register 330 case DW_OP_breg30: // 0x8e 1 ULEB128 register 331 case DW_OP_breg31: // 0x8f 1 ULEB128 register 332 case DW_OP_regx: // 0x90 1 ULEB128 register 333 case DW_OP_fbreg: // 0x91 1 SLEB128 offset 334 case DW_OP_piece: // 0x93 1 ULEB128 size of piece addressed 335 case DW_OP_convert: // 0xa8 1 ULEB128 offset 336 case DW_OP_reinterpret: // 0xa9 1 ULEB128 offset 337 case DW_OP_addrx: // 0xa1 1 ULEB128 index 338 case DW_OP_constx: // 0xa2 1 ULEB128 index 339 case DW_OP_xderef_type: // 0xa7 1 ULEB128 index 340 case DW_OP_GNU_addr_index: // 0xfb 1 ULEB128 index 341 case DW_OP_GNU_const_index: // 0xfc 1 ULEB128 index 342 data.Skip_LEB128(&offset); 343 return offset - data_offset; 344 345 // All opcodes that have a 2 ULEB (signed or unsigned) arguments 346 case DW_OP_bregx: // 0x92 2 ULEB128 register followed by SLEB128 offset 347 case DW_OP_bit_piece: // 0x9d ULEB128 bit size, ULEB128 bit offset (DWARF3); 348 case DW_OP_regval_type: // 0xa5 ULEB128 + ULEB128 349 data.Skip_LEB128(&offset); 350 data.Skip_LEB128(&offset); 351 return offset - data_offset; 352 353 case DW_OP_implicit_value: // 0x9e ULEB128 size followed by block of that size 354 // (DWARF4) 355 { 356 uint64_t block_len = data.Skip_LEB128(&offset); 357 offset += block_len; 358 return offset - data_offset; 359 } 360 361 case DW_OP_implicit_pointer: // 0xa0 4-byte (or 8-byte for DWARF 64) constant 362 // + LEB128 363 { 364 data.Skip_LEB128(&offset); 365 return DWARFUnit::GetAddressByteSize(dwarf_cu) + offset - data_offset; 366 } 367 368 case DW_OP_GNU_entry_value: 369 case DW_OP_entry_value: // 0xa3 ULEB128 size + variable-length block 370 { 371 uint64_t subexpr_len = data.GetULEB128(&offset); 372 return (offset - data_offset) + subexpr_len; 373 } 374 375 case DW_OP_const_type: // 0xa4 ULEB128 + size + variable-length block 376 { 377 data.Skip_LEB128(&offset); 378 uint8_t length = data.GetU8(&offset); 379 return (offset - data_offset) + length; 380 } 381 382 case DW_OP_LLVM_user: // 0xe9: ULEB128 + variable length constant 383 { 384 uint64_t constants = data.GetULEB128(&offset); 385 return (offset - data_offset) + constants; 386 } 387 } 388 389 if (dwarf_cu) 390 return dwarf_cu->GetSymbolFileDWARF().GetVendorDWARFOpcodeSize( 391 data, data_offset, op); 392 393 return LLDB_INVALID_OFFSET; 394 } 395 396 llvm::Expected<lldb::addr_t> 397 DWARFExpression::GetLocation_DW_OP_addr(const DWARFUnit *dwarf_cu) const { 398 lldb::offset_t offset = 0; 399 while (m_data.ValidOffset(offset)) { 400 const LocationAtom op = static_cast<LocationAtom>(m_data.GetU8(&offset)); 401 402 if (op == DW_OP_addr) 403 return m_data.GetAddress(&offset); 404 405 if (op == DW_OP_GNU_addr_index || op == DW_OP_addrx) { 406 const uint64_t index = m_data.GetULEB128(&offset); 407 if (dwarf_cu) 408 return dwarf_cu->ReadAddressFromDebugAddrSection(index); 409 return llvm::createStringError("cannot evaluate %s without a DWARF unit", 410 DW_OP_value_to_name(op)); 411 } 412 413 const lldb::offset_t op_arg_size = 414 GetOpcodeDataSize(m_data, offset, op, dwarf_cu); 415 if (op_arg_size == LLDB_INVALID_OFFSET) 416 return llvm::createStringError("cannot get opcode data size for %s", 417 DW_OP_value_to_name(op)); 418 419 offset += op_arg_size; 420 } 421 422 return LLDB_INVALID_ADDRESS; 423 } 424 425 bool DWARFExpression::Update_DW_OP_addr(const DWARFUnit *dwarf_cu, 426 lldb::addr_t file_addr) { 427 lldb::offset_t offset = 0; 428 while (m_data.ValidOffset(offset)) { 429 const LocationAtom op = static_cast<LocationAtom>(m_data.GetU8(&offset)); 430 431 if (op == DW_OP_addr) { 432 const uint32_t addr_byte_size = m_data.GetAddressByteSize(); 433 // We have to make a copy of the data as we don't know if this data is 434 // from a read only memory mapped buffer, so we duplicate all of the data 435 // first, then modify it, and if all goes well, we then replace the data 436 // for this expression 437 438 // Make en encoder that contains a copy of the location expression data 439 // so we can write the address into the buffer using the correct byte 440 // order. 441 DataEncoder encoder(m_data.GetDataStart(), m_data.GetByteSize(), 442 m_data.GetByteOrder(), addr_byte_size); 443 444 // Replace the address in the new buffer 445 if (encoder.PutAddress(offset, file_addr) == UINT32_MAX) 446 return false; 447 448 // All went well, so now we can reset the data using a shared pointer to 449 // the heap data so "m_data" will now correctly manage the heap data. 450 m_data.SetData(encoder.GetDataBuffer()); 451 return true; 452 } 453 if (op == DW_OP_addrx) { 454 // Replace DW_OP_addrx with DW_OP_addr, since we can't modify the 455 // read-only debug_addr table. 456 // Subtract one to account for the opcode. 457 llvm::ArrayRef data_before_op = m_data.GetData().take_front(offset - 1); 458 459 // Read the addrx index to determine how many bytes it needs. 460 const lldb::offset_t old_offset = offset; 461 m_data.GetULEB128(&offset); 462 if (old_offset == offset) 463 return false; 464 llvm::ArrayRef data_after_op = m_data.GetData().drop_front(offset); 465 466 DataEncoder encoder(m_data.GetByteOrder(), m_data.GetAddressByteSize()); 467 encoder.AppendData(data_before_op); 468 encoder.AppendU8(DW_OP_addr); 469 encoder.AppendAddress(file_addr); 470 encoder.AppendData(data_after_op); 471 m_data.SetData(encoder.GetDataBuffer()); 472 return true; 473 } 474 const lldb::offset_t op_arg_size = 475 GetOpcodeDataSize(m_data, offset, op, dwarf_cu); 476 if (op_arg_size == LLDB_INVALID_OFFSET) 477 break; 478 offset += op_arg_size; 479 } 480 return false; 481 } 482 483 bool DWARFExpression::ContainsThreadLocalStorage( 484 const DWARFUnit *dwarf_cu) const { 485 lldb::offset_t offset = 0; 486 while (m_data.ValidOffset(offset)) { 487 const LocationAtom op = static_cast<LocationAtom>(m_data.GetU8(&offset)); 488 489 if (op == DW_OP_form_tls_address || op == DW_OP_GNU_push_tls_address) 490 return true; 491 const lldb::offset_t op_arg_size = 492 GetOpcodeDataSize(m_data, offset, op, dwarf_cu); 493 if (op_arg_size == LLDB_INVALID_OFFSET) 494 return false; 495 offset += op_arg_size; 496 } 497 return false; 498 } 499 bool DWARFExpression::LinkThreadLocalStorage( 500 const DWARFUnit *dwarf_cu, 501 std::function<lldb::addr_t(lldb::addr_t file_addr)> const 502 &link_address_callback) { 503 const uint32_t addr_byte_size = m_data.GetAddressByteSize(); 504 // We have to make a copy of the data as we don't know if this data is from a 505 // read only memory mapped buffer, so we duplicate all of the data first, 506 // then modify it, and if all goes well, we then replace the data for this 507 // expression. 508 // Make en encoder that contains a copy of the location expression data so we 509 // can write the address into the buffer using the correct byte order. 510 DataEncoder encoder(m_data.GetDataStart(), m_data.GetByteSize(), 511 m_data.GetByteOrder(), addr_byte_size); 512 513 lldb::offset_t offset = 0; 514 lldb::offset_t const_offset = 0; 515 lldb::addr_t const_value = 0; 516 size_t const_byte_size = 0; 517 while (m_data.ValidOffset(offset)) { 518 const LocationAtom op = static_cast<LocationAtom>(m_data.GetU8(&offset)); 519 520 bool decoded_data = false; 521 switch (op) { 522 case DW_OP_const4u: 523 // Remember the const offset in case we later have a 524 // DW_OP_form_tls_address or DW_OP_GNU_push_tls_address 525 const_offset = offset; 526 const_value = m_data.GetU32(&offset); 527 decoded_data = true; 528 const_byte_size = 4; 529 break; 530 531 case DW_OP_const8u: 532 // Remember the const offset in case we later have a 533 // DW_OP_form_tls_address or DW_OP_GNU_push_tls_address 534 const_offset = offset; 535 const_value = m_data.GetU64(&offset); 536 decoded_data = true; 537 const_byte_size = 8; 538 break; 539 540 case DW_OP_form_tls_address: 541 case DW_OP_GNU_push_tls_address: 542 // DW_OP_form_tls_address and DW_OP_GNU_push_tls_address must be preceded 543 // by a file address on the stack. We assume that DW_OP_const4u or 544 // DW_OP_const8u is used for these values, and we check that the last 545 // opcode we got before either of these was DW_OP_const4u or 546 // DW_OP_const8u. If so, then we can link the value accordingly. For 547 // Darwin, the value in the DW_OP_const4u or DW_OP_const8u is the file 548 // address of a structure that contains a function pointer, the pthread 549 // key and the offset into the data pointed to by the pthread key. So we 550 // must link this address and also set the module of this expression to 551 // the new_module_sp so we can resolve the file address correctly 552 if (const_byte_size > 0) { 553 lldb::addr_t linked_file_addr = link_address_callback(const_value); 554 if (linked_file_addr == LLDB_INVALID_ADDRESS) 555 return false; 556 // Replace the address in the new buffer 557 if (encoder.PutUnsigned(const_offset, const_byte_size, 558 linked_file_addr) == UINT32_MAX) 559 return false; 560 } 561 break; 562 563 default: 564 const_offset = 0; 565 const_value = 0; 566 const_byte_size = 0; 567 break; 568 } 569 570 if (!decoded_data) { 571 const lldb::offset_t op_arg_size = 572 GetOpcodeDataSize(m_data, offset, op, dwarf_cu); 573 if (op_arg_size == LLDB_INVALID_OFFSET) 574 return false; 575 else 576 offset += op_arg_size; 577 } 578 } 579 580 m_data.SetData(encoder.GetDataBuffer()); 581 return true; 582 } 583 584 static llvm::Error Evaluate_DW_OP_entry_value(std::vector<Value> &stack, 585 ExecutionContext *exe_ctx, 586 RegisterContext *reg_ctx, 587 const DataExtractor &opcodes, 588 lldb::offset_t &opcode_offset, 589 Log *log) { 590 // DW_OP_entry_value(sub-expr) describes the location a variable had upon 591 // function entry: this variable location is presumed to be optimized out at 592 // the current PC value. The caller of the function may have call site 593 // information that describes an alternate location for the variable (e.g. a 594 // constant literal, or a spilled stack value) in the parent frame. 595 // 596 // Example (this is pseudo-code & pseudo-DWARF, but hopefully illustrative): 597 // 598 // void child(int &sink, int x) { 599 // ... 600 // /* "x" gets optimized out. */ 601 // 602 // /* The location of "x" here is: DW_OP_entry_value($reg2). */ 603 // ++sink; 604 // } 605 // 606 // void parent() { 607 // int sink; 608 // 609 // /* 610 // * The callsite information emitted here is: 611 // * 612 // * DW_TAG_call_site 613 // * DW_AT_return_pc ... (for "child(sink, 123);") 614 // * DW_TAG_call_site_parameter (for "sink") 615 // * DW_AT_location ($reg1) 616 // * DW_AT_call_value ($SP - 8) 617 // * DW_TAG_call_site_parameter (for "x") 618 // * DW_AT_location ($reg2) 619 // * DW_AT_call_value ($literal 123) 620 // * 621 // * DW_TAG_call_site 622 // * DW_AT_return_pc ... (for "child(sink, 456);") 623 // * ... 624 // */ 625 // child(sink, 123); 626 // child(sink, 456); 627 // } 628 // 629 // When the program stops at "++sink" within `child`, the debugger determines 630 // the call site by analyzing the return address. Once the call site is found, 631 // the debugger determines which parameter is referenced by DW_OP_entry_value 632 // and evaluates the corresponding location for that parameter in `parent`. 633 634 // 1. Find the function which pushed the current frame onto the stack. 635 if ((!exe_ctx || !exe_ctx->HasTargetScope()) || !reg_ctx) { 636 return llvm::createStringError("no exe/reg context"); 637 } 638 639 StackFrame *current_frame = exe_ctx->GetFramePtr(); 640 Thread *thread = exe_ctx->GetThreadPtr(); 641 if (!current_frame || !thread) 642 return llvm::createStringError("no current frame/thread"); 643 644 Target &target = exe_ctx->GetTargetRef(); 645 StackFrameSP parent_frame = nullptr; 646 addr_t return_pc = LLDB_INVALID_ADDRESS; 647 uint32_t current_frame_idx = current_frame->GetFrameIndex(); 648 649 for (uint32_t parent_frame_idx = current_frame_idx + 1;;parent_frame_idx++) { 650 parent_frame = thread->GetStackFrameAtIndex(parent_frame_idx); 651 // If this is null, we're at the end of the stack. 652 if (!parent_frame) 653 break; 654 655 // Record the first valid return address, even if this is an inlined frame, 656 // in order to look up the associated call edge in the first non-inlined 657 // parent frame. 658 if (return_pc == LLDB_INVALID_ADDRESS) { 659 return_pc = parent_frame->GetFrameCodeAddress().GetLoadAddress(&target); 660 LLDB_LOG(log, "immediate ancestor with pc = {0:x}", return_pc); 661 } 662 663 // If we've found an inlined frame, skip it (these have no call site 664 // parameters). 665 if (parent_frame->IsInlined()) 666 continue; 667 668 // We've found the first non-inlined parent frame. 669 break; 670 } 671 if (!parent_frame || !parent_frame->GetRegisterContext()) { 672 return llvm::createStringError("no parent frame with reg ctx"); 673 } 674 675 Function *parent_func = 676 parent_frame->GetSymbolContext(eSymbolContextFunction).function; 677 if (!parent_func) 678 return llvm::createStringError("no parent function"); 679 680 // 2. Find the call edge in the parent function responsible for creating the 681 // current activation. 682 Function *current_func = 683 current_frame->GetSymbolContext(eSymbolContextFunction).function; 684 if (!current_func) 685 return llvm::createStringError("no current function"); 686 687 CallEdge *call_edge = nullptr; 688 ModuleList &modlist = target.GetImages(); 689 ExecutionContext parent_exe_ctx = *exe_ctx; 690 parent_exe_ctx.SetFrameSP(parent_frame); 691 if (!parent_frame->IsArtificial()) { 692 // If the parent frame is not artificial, the current activation may be 693 // produced by an ambiguous tail call. In this case, refuse to proceed. 694 call_edge = parent_func->GetCallEdgeForReturnAddress(return_pc, target); 695 if (!call_edge) { 696 return llvm::createStringError( 697 llvm::formatv("no call edge for retn-pc = {0:x} in parent frame {1}", 698 return_pc, parent_func->GetName())); 699 } 700 Function *callee_func = call_edge->GetCallee(modlist, parent_exe_ctx); 701 if (callee_func != current_func) { 702 return llvm::createStringError( 703 "ambiguous call sequence, can't find real parent frame"); 704 } 705 } else { 706 // The StackFrameList solver machinery has deduced that an unambiguous tail 707 // call sequence that produced the current activation. The first edge in 708 // the parent that points to the current function must be valid. 709 for (auto &edge : parent_func->GetTailCallingEdges()) { 710 if (edge->GetCallee(modlist, parent_exe_ctx) == current_func) { 711 call_edge = edge.get(); 712 break; 713 } 714 } 715 } 716 if (!call_edge) 717 return llvm::createStringError("no unambiguous edge from parent " 718 "to current function"); 719 720 // 3. Attempt to locate the DW_OP_entry_value expression in the set of 721 // available call site parameters. If found, evaluate the corresponding 722 // parameter in the context of the parent frame. 723 const uint32_t subexpr_len = opcodes.GetULEB128(&opcode_offset); 724 const void *subexpr_data = opcodes.GetData(&opcode_offset, subexpr_len); 725 if (!subexpr_data) 726 return llvm::createStringError("subexpr could not be read"); 727 728 const CallSiteParameter *matched_param = nullptr; 729 for (const CallSiteParameter ¶m : call_edge->GetCallSiteParameters()) { 730 DataExtractor param_subexpr_extractor; 731 if (!param.LocationInCallee.GetExpressionData(param_subexpr_extractor)) 732 continue; 733 lldb::offset_t param_subexpr_offset = 0; 734 const void *param_subexpr_data = 735 param_subexpr_extractor.GetData(¶m_subexpr_offset, subexpr_len); 736 if (!param_subexpr_data || 737 param_subexpr_extractor.BytesLeft(param_subexpr_offset) != 0) 738 continue; 739 740 // At this point, the DW_OP_entry_value sub-expression and the callee-side 741 // expression in the call site parameter are known to have the same length. 742 // Check whether they are equal. 743 // 744 // Note that an equality check is sufficient: the contents of the 745 // DW_OP_entry_value subexpression are only used to identify the right call 746 // site parameter in the parent, and do not require any special handling. 747 if (memcmp(subexpr_data, param_subexpr_data, subexpr_len) == 0) { 748 matched_param = ¶m; 749 break; 750 } 751 } 752 if (!matched_param) 753 return llvm::createStringError("no matching call site param found"); 754 755 // TODO: Add support for DW_OP_push_object_address within a DW_OP_entry_value 756 // subexpresion whenever llvm does. 757 const DWARFExpressionList ¶m_expr = matched_param->LocationInCaller; 758 759 llvm::Expected<Value> maybe_result = param_expr.Evaluate( 760 &parent_exe_ctx, parent_frame->GetRegisterContext().get(), 761 LLDB_INVALID_ADDRESS, 762 /*initial_value_ptr=*/nullptr, 763 /*object_address_ptr=*/nullptr); 764 if (!maybe_result) { 765 LLDB_LOG(log, 766 "Evaluate_DW_OP_entry_value: call site param evaluation failed"); 767 return maybe_result.takeError(); 768 } 769 770 stack.push_back(*maybe_result); 771 return llvm::Error::success(); 772 } 773 774 namespace { 775 /// The location description kinds described by the DWARF v5 776 /// specification. Composite locations are handled out-of-band and 777 /// thus aren't part of the enum. 778 enum LocationDescriptionKind { 779 Empty, 780 Memory, 781 Register, 782 Implicit 783 /* Composite*/ 784 }; 785 /// Adjust value's ValueType according to the kind of location description. 786 void UpdateValueTypeFromLocationDescription(Log *log, const DWARFUnit *dwarf_cu, 787 LocationDescriptionKind kind, 788 Value *value = nullptr) { 789 // Note that this function is conflating DWARF expressions with 790 // DWARF location descriptions. Perhaps it would be better to define 791 // a wrapper for DWARFExpression::Eval() that deals with DWARF 792 // location descriptions (which consist of one or more DWARF 793 // expressions). But doing this would mean we'd also need factor the 794 // handling of DW_OP_(bit_)piece out of this function. 795 if (dwarf_cu && dwarf_cu->GetVersion() >= 4) { 796 const char *log_msg = "DWARF location description kind: %s"; 797 switch (kind) { 798 case Empty: 799 LLDB_LOGF(log, log_msg, "Empty"); 800 break; 801 case Memory: 802 LLDB_LOGF(log, log_msg, "Memory"); 803 if (value->GetValueType() == Value::ValueType::Scalar) 804 value->SetValueType(Value::ValueType::LoadAddress); 805 break; 806 case Register: 807 LLDB_LOGF(log, log_msg, "Register"); 808 value->SetValueType(Value::ValueType::Scalar); 809 break; 810 case Implicit: 811 LLDB_LOGF(log, log_msg, "Implicit"); 812 if (value->GetValueType() == Value::ValueType::LoadAddress) 813 value->SetValueType(Value::ValueType::Scalar); 814 break; 815 } 816 } 817 } 818 } // namespace 819 820 /// Helper function to move common code used to resolve a file address and turn 821 /// into a load address. 822 /// 823 /// \param exe_ctx Pointer to the execution context 824 /// \param module_sp shared_ptr contains the module if we have one 825 /// \param dw_op_type C-style string used to vary the error output 826 /// \param file_addr the file address we are trying to resolve and turn into a 827 /// load address 828 /// \param so_addr out parameter, will be set to load address or section offset 829 /// \param check_sectionoffset bool which determines if having a section offset 830 /// but not a load address is considerd a success 831 /// \returns std::optional containing the load address if resolving and getting 832 /// the load address succeed or an empty Optinal otherwise. If 833 /// check_sectionoffset is true we consider LLDB_INVALID_ADDRESS a 834 /// success if so_addr.IsSectionOffset() is true. 835 static llvm::Expected<lldb::addr_t> 836 ResolveLoadAddress(ExecutionContext *exe_ctx, lldb::ModuleSP &module_sp, 837 const char *dw_op_type, lldb::addr_t file_addr, 838 Address &so_addr, bool check_sectionoffset = false) { 839 if (!module_sp) 840 return llvm::createStringError("need module to resolve file address for %s", 841 dw_op_type); 842 843 if (!module_sp->ResolveFileAddress(file_addr, so_addr)) 844 return llvm::createStringError("failed to resolve file address in module"); 845 846 const addr_t load_addr = so_addr.GetLoadAddress(exe_ctx->GetTargetPtr()); 847 848 if (load_addr == LLDB_INVALID_ADDRESS && 849 (check_sectionoffset && !so_addr.IsSectionOffset())) 850 return llvm::createStringError("failed to resolve load address"); 851 852 return load_addr; 853 } 854 855 /// Helper function to move common code used to load sized data from a uint8_t 856 /// buffer. 857 /// 858 /// \param addr_bytes uint8_t buffer containg raw data 859 /// \param size_addr_bytes how large is the underlying raw data 860 /// \param byte_order what is the byter order of the underlyig data 861 /// \param size How much of the underlying data we want to use 862 /// \return The underlying data converted into a Scalar 863 static Scalar DerefSizeExtractDataHelper(uint8_t *addr_bytes, 864 size_t size_addr_bytes, 865 ByteOrder byte_order, size_t size) { 866 DataExtractor addr_data(addr_bytes, size_addr_bytes, byte_order, size); 867 868 lldb::offset_t addr_data_offset = 0; 869 if (size <= 8) 870 return addr_data.GetMaxU64(&addr_data_offset, size); 871 else 872 return addr_data.GetAddress(&addr_data_offset); 873 } 874 875 llvm::Expected<Value> DWARFExpression::Evaluate( 876 ExecutionContext *exe_ctx, RegisterContext *reg_ctx, 877 lldb::ModuleSP module_sp, const DataExtractor &opcodes, 878 const DWARFUnit *dwarf_cu, const lldb::RegisterKind reg_kind, 879 const Value *initial_value_ptr, const Value *object_address_ptr) { 880 881 if (opcodes.GetByteSize() == 0) 882 return llvm::createStringError( 883 "no location, value may have been optimized out"); 884 std::vector<Value> stack; 885 886 Process *process = nullptr; 887 StackFrame *frame = nullptr; 888 Target *target = nullptr; 889 890 if (exe_ctx) { 891 process = exe_ctx->GetProcessPtr(); 892 frame = exe_ctx->GetFramePtr(); 893 target = exe_ctx->GetTargetPtr(); 894 } 895 if (reg_ctx == nullptr && frame) 896 reg_ctx = frame->GetRegisterContext().get(); 897 898 if (initial_value_ptr) 899 stack.push_back(*initial_value_ptr); 900 901 lldb::offset_t offset = 0; 902 Value tmp; 903 uint32_t reg_num; 904 905 /// Insertion point for evaluating multi-piece expression. 906 uint64_t op_piece_offset = 0; 907 Value pieces; // Used for DW_OP_piece 908 909 Log *log = GetLog(LLDBLog::Expressions); 910 // A generic type is "an integral type that has the size of an address and an 911 // unspecified signedness". For now, just use the signedness of the operand. 912 // TODO: Implement a real typed stack, and store the genericness of the value 913 // there. 914 auto to_generic = [&](auto v) { 915 // TODO: Avoid implicit trunc? 916 // See https://github.com/llvm/llvm-project/issues/112510. 917 bool is_signed = std::is_signed<decltype(v)>::value; 918 return Scalar(llvm::APSInt(llvm::APInt(8 * opcodes.GetAddressByteSize(), v, 919 is_signed, /*implicitTrunc=*/true), 920 !is_signed)); 921 }; 922 923 // The default kind is a memory location. This is updated by any 924 // operation that changes this, such as DW_OP_stack_value, and reset 925 // by composition operations like DW_OP_piece. 926 LocationDescriptionKind dwarf4_location_description_kind = Memory; 927 928 while (opcodes.ValidOffset(offset)) { 929 const lldb::offset_t op_offset = offset; 930 const uint8_t op = opcodes.GetU8(&offset); 931 932 if (log && log->GetVerbose()) { 933 size_t count = stack.size(); 934 LLDB_LOGF(log, "Stack before operation has %" PRIu64 " values:", 935 (uint64_t)count); 936 for (size_t i = 0; i < count; ++i) { 937 StreamString new_value; 938 new_value.Printf("[%" PRIu64 "]", (uint64_t)i); 939 stack[i].Dump(&new_value); 940 LLDB_LOGF(log, " %s", new_value.GetData()); 941 } 942 LLDB_LOGF(log, "0x%8.8" PRIx64 ": %s", op_offset, 943 DW_OP_value_to_name(op)); 944 } 945 946 if (std::optional<unsigned> arity = 947 llvm::dwarf::OperationArity(static_cast<LocationAtom>(op))) { 948 if (stack.size() < *arity) 949 return llvm::createStringError( 950 "%s needs at least %d stack entries (stack has %d entries)", 951 DW_OP_value_to_name(op), *arity, stack.size()); 952 } 953 954 switch (op) { 955 // The DW_OP_addr operation has a single operand that encodes a machine 956 // address and whose size is the size of an address on the target machine. 957 case DW_OP_addr: 958 stack.push_back(Scalar(opcodes.GetAddress(&offset))); 959 if (target && 960 target->GetArchitecture().GetCore() == ArchSpec::eCore_wasm32) { 961 // wasm file sections aren't mapped into memory, therefore addresses can 962 // never point into a file section and are always LoadAddresses. 963 stack.back().SetValueType(Value::ValueType::LoadAddress); 964 } else { 965 stack.back().SetValueType(Value::ValueType::FileAddress); 966 } 967 break; 968 969 // The DW_OP_addr_sect_offset4 is used for any location expressions in 970 // shared libraries that have a location like: 971 // DW_OP_addr(0x1000) 972 // If this address resides in a shared library, then this virtual address 973 // won't make sense when it is evaluated in the context of a running 974 // process where shared libraries have been slid. To account for this, this 975 // new address type where we can store the section pointer and a 4 byte 976 // offset. 977 // case DW_OP_addr_sect_offset4: 978 // { 979 // result_type = eResultTypeFileAddress; 980 // lldb::Section *sect = (lldb::Section 981 // *)opcodes.GetMaxU64(&offset, sizeof(void *)); 982 // lldb::addr_t sect_offset = opcodes.GetU32(&offset); 983 // 984 // Address so_addr (sect, sect_offset); 985 // lldb::addr_t load_addr = so_addr.GetLoadAddress(); 986 // if (load_addr != LLDB_INVALID_ADDRESS) 987 // { 988 // // We successfully resolve a file address to a load 989 // // address. 990 // stack.push_back(load_addr); 991 // break; 992 // } 993 // else 994 // { 995 // // We were able 996 // if (error_ptr) 997 // error_ptr->SetErrorStringWithFormat ("Section %s in 998 // %s is not currently loaded.\n", 999 // sect->GetName().AsCString(), 1000 // sect->GetModule()->GetFileSpec().GetFilename().AsCString()); 1001 // return false; 1002 // } 1003 // } 1004 // break; 1005 1006 // OPCODE: DW_OP_deref 1007 // OPERANDS: none 1008 // DESCRIPTION: Pops the top stack entry and treats it as an address. 1009 // The value retrieved from that address is pushed. The size of the data 1010 // retrieved from the dereferenced address is the size of an address on the 1011 // target machine. 1012 case DW_OP_deref: { 1013 if (stack.empty()) 1014 return llvm::createStringError( 1015 "expression stack empty for DW_OP_deref"); 1016 Value::ValueType value_type = stack.back().GetValueType(); 1017 switch (value_type) { 1018 case Value::ValueType::HostAddress: { 1019 void *src = (void *)stack.back().GetScalar().ULongLong(); 1020 intptr_t ptr; 1021 ::memcpy(&ptr, src, sizeof(void *)); 1022 stack.back().GetScalar() = ptr; 1023 stack.back().ClearContext(); 1024 } break; 1025 case Value::ValueType::FileAddress: { 1026 auto file_addr = stack.back().GetScalar().ULongLong( 1027 LLDB_INVALID_ADDRESS); 1028 1029 Address so_addr; 1030 auto maybe_load_addr = ResolveLoadAddress( 1031 exe_ctx, module_sp, "DW_OP_deref", file_addr, so_addr); 1032 1033 if (!maybe_load_addr) 1034 return maybe_load_addr.takeError(); 1035 1036 stack.back().GetScalar() = *maybe_load_addr; 1037 // Fall through to load address promotion code below. 1038 } 1039 [[fallthrough]]; 1040 case Value::ValueType::Scalar: 1041 // Promote Scalar to LoadAddress and fall through. 1042 stack.back().SetValueType(Value::ValueType::LoadAddress); 1043 [[fallthrough]]; 1044 case Value::ValueType::LoadAddress: 1045 if (exe_ctx) { 1046 if (process) { 1047 lldb::addr_t pointer_addr = 1048 stack.back().GetScalar().ULongLong(LLDB_INVALID_ADDRESS); 1049 Status error; 1050 lldb::addr_t pointer_value = 1051 process->ReadPointerFromMemory(pointer_addr, error); 1052 if (pointer_value != LLDB_INVALID_ADDRESS) { 1053 if (ABISP abi_sp = process->GetABI()) 1054 pointer_value = abi_sp->FixCodeAddress(pointer_value); 1055 stack.back().GetScalar() = pointer_value; 1056 stack.back().ClearContext(); 1057 } else { 1058 return llvm::createStringError( 1059 "Failed to dereference pointer from 0x%" PRIx64 1060 " for DW_OP_deref: %s\n", 1061 pointer_addr, error.AsCString()); 1062 } 1063 } else { 1064 return llvm::createStringError("NULL process for DW_OP_deref"); 1065 } 1066 } else { 1067 return llvm::createStringError( 1068 "NULL execution context for DW_OP_deref"); 1069 } 1070 break; 1071 1072 case Value::ValueType::Invalid: 1073 return llvm::createStringError("invalid value type for DW_OP_deref"); 1074 } 1075 1076 } break; 1077 1078 // OPCODE: DW_OP_deref_size 1079 // OPERANDS: 1 1080 // 1 - uint8_t that specifies the size of the data to dereference. 1081 // DESCRIPTION: Behaves like the DW_OP_deref operation: it pops the top 1082 // stack entry and treats it as an address. The value retrieved from that 1083 // address is pushed. In the DW_OP_deref_size operation, however, the size 1084 // in bytes of the data retrieved from the dereferenced address is 1085 // specified by the single operand. This operand is a 1-byte unsigned 1086 // integral constant whose value may not be larger than the size of an 1087 // address on the target machine. The data retrieved is zero extended to 1088 // the size of an address on the target machine before being pushed on the 1089 // expression stack. 1090 case DW_OP_deref_size: { 1091 if (stack.empty()) { 1092 return llvm::createStringError( 1093 "expression stack empty for DW_OP_deref_size"); 1094 } 1095 uint8_t size = opcodes.GetU8(&offset); 1096 if (size > 8) { 1097 return llvm::createStringError( 1098 "Invalid address size for DW_OP_deref_size: %d\n", size); 1099 } 1100 Value::ValueType value_type = stack.back().GetValueType(); 1101 switch (value_type) { 1102 case Value::ValueType::HostAddress: { 1103 void *src = (void *)stack.back().GetScalar().ULongLong(); 1104 intptr_t ptr; 1105 ::memcpy(&ptr, src, sizeof(void *)); 1106 // I can't decide whether the size operand should apply to the bytes in 1107 // their 1108 // lldb-host endianness or the target endianness.. I doubt this'll ever 1109 // come up but I'll opt for assuming big endian regardless. 1110 switch (size) { 1111 case 1: 1112 ptr = ptr & 0xff; 1113 break; 1114 case 2: 1115 ptr = ptr & 0xffff; 1116 break; 1117 case 3: 1118 ptr = ptr & 0xffffff; 1119 break; 1120 case 4: 1121 ptr = ptr & 0xffffffff; 1122 break; 1123 // the casts are added to work around the case where intptr_t is a 32 1124 // bit quantity; 1125 // presumably we won't hit the 5..7 cases if (void*) is 32-bits in this 1126 // program. 1127 case 5: 1128 ptr = (intptr_t)ptr & 0xffffffffffULL; 1129 break; 1130 case 6: 1131 ptr = (intptr_t)ptr & 0xffffffffffffULL; 1132 break; 1133 case 7: 1134 ptr = (intptr_t)ptr & 0xffffffffffffffULL; 1135 break; 1136 default: 1137 break; 1138 } 1139 stack.back().GetScalar() = ptr; 1140 stack.back().ClearContext(); 1141 } break; 1142 case Value::ValueType::FileAddress: { 1143 auto file_addr = 1144 stack.back().GetScalar().ULongLong(LLDB_INVALID_ADDRESS); 1145 Address so_addr; 1146 auto maybe_load_addr = ResolveLoadAddress( 1147 exe_ctx, module_sp, "DW_OP_deref_size", file_addr, so_addr, 1148 /*check_sectionoffset=*/true); 1149 1150 if (!maybe_load_addr) 1151 return maybe_load_addr.takeError(); 1152 1153 addr_t load_addr = *maybe_load_addr; 1154 1155 if (load_addr == LLDB_INVALID_ADDRESS && so_addr.IsSectionOffset()) { 1156 uint8_t addr_bytes[8]; 1157 Status error; 1158 1159 if (target && 1160 target->ReadMemory(so_addr, &addr_bytes, size, error, 1161 /*force_live_memory=*/false) == size) { 1162 ObjectFile *objfile = module_sp->GetObjectFile(); 1163 1164 stack.back().GetScalar() = DerefSizeExtractDataHelper( 1165 addr_bytes, size, objfile->GetByteOrder(), size); 1166 stack.back().ClearContext(); 1167 break; 1168 } else { 1169 return llvm::createStringError( 1170 "Failed to dereference pointer for DW_OP_deref_size: " 1171 "%s\n", 1172 error.AsCString()); 1173 } 1174 } 1175 stack.back().GetScalar() = load_addr; 1176 // Fall through to load address promotion code below. 1177 } 1178 1179 [[fallthrough]]; 1180 case Value::ValueType::Scalar: 1181 case Value::ValueType::LoadAddress: 1182 if (exe_ctx) { 1183 if (process) { 1184 lldb::addr_t pointer_addr = 1185 stack.back().GetScalar().ULongLong(LLDB_INVALID_ADDRESS); 1186 uint8_t addr_bytes[sizeof(lldb::addr_t)]; 1187 Status error; 1188 if (process->ReadMemory(pointer_addr, &addr_bytes, size, error) == 1189 size) { 1190 1191 stack.back().GetScalar() = 1192 DerefSizeExtractDataHelper(addr_bytes, sizeof(addr_bytes), 1193 process->GetByteOrder(), size); 1194 stack.back().ClearContext(); 1195 } else { 1196 return llvm::createStringError( 1197 "Failed to dereference pointer from 0x%" PRIx64 1198 " for DW_OP_deref: %s\n", 1199 pointer_addr, error.AsCString()); 1200 } 1201 } else { 1202 1203 return llvm::createStringError("NULL process for DW_OP_deref_size"); 1204 } 1205 } else { 1206 return llvm::createStringError( 1207 "NULL execution context for DW_OP_deref_size"); 1208 } 1209 break; 1210 1211 case Value::ValueType::Invalid: 1212 1213 return llvm::createStringError("invalid value for DW_OP_deref_size"); 1214 } 1215 1216 } break; 1217 1218 // OPCODE: DW_OP_xderef_size 1219 // OPERANDS: 1 1220 // 1 - uint8_t that specifies the size of the data to dereference. 1221 // DESCRIPTION: Behaves like the DW_OP_xderef operation: the entry at 1222 // the top of the stack is treated as an address. The second stack entry is 1223 // treated as an "address space identifier" for those architectures that 1224 // support multiple address spaces. The top two stack elements are popped, 1225 // a data item is retrieved through an implementation-defined address 1226 // calculation and pushed as the new stack top. In the DW_OP_xderef_size 1227 // operation, however, the size in bytes of the data retrieved from the 1228 // dereferenced address is specified by the single operand. This operand is 1229 // a 1-byte unsigned integral constant whose value may not be larger than 1230 // the size of an address on the target machine. The data retrieved is zero 1231 // extended to the size of an address on the target machine before being 1232 // pushed on the expression stack. 1233 case DW_OP_xderef_size: 1234 return llvm::createStringError("unimplemented opcode: DW_OP_xderef_size"); 1235 // OPCODE: DW_OP_xderef 1236 // OPERANDS: none 1237 // DESCRIPTION: Provides an extended dereference mechanism. The entry at 1238 // the top of the stack is treated as an address. The second stack entry is 1239 // treated as an "address space identifier" for those architectures that 1240 // support multiple address spaces. The top two stack elements are popped, 1241 // a data item is retrieved through an implementation-defined address 1242 // calculation and pushed as the new stack top. The size of the data 1243 // retrieved from the dereferenced address is the size of an address on the 1244 // target machine. 1245 case DW_OP_xderef: 1246 return llvm::createStringError("unimplemented opcode: DW_OP_xderef"); 1247 1248 // All DW_OP_constXXX opcodes have a single operand as noted below: 1249 // 1250 // Opcode Operand 1 1251 // DW_OP_const1u 1-byte unsigned integer constant 1252 // DW_OP_const1s 1-byte signed integer constant 1253 // DW_OP_const2u 2-byte unsigned integer constant 1254 // DW_OP_const2s 2-byte signed integer constant 1255 // DW_OP_const4u 4-byte unsigned integer constant 1256 // DW_OP_const4s 4-byte signed integer constant 1257 // DW_OP_const8u 8-byte unsigned integer constant 1258 // DW_OP_const8s 8-byte signed integer constant 1259 // DW_OP_constu unsigned LEB128 integer constant 1260 // DW_OP_consts signed LEB128 integer constant 1261 case DW_OP_const1u: 1262 stack.push_back(to_generic(opcodes.GetU8(&offset))); 1263 break; 1264 case DW_OP_const1s: 1265 stack.push_back(to_generic((int8_t)opcodes.GetU8(&offset))); 1266 break; 1267 case DW_OP_const2u: 1268 stack.push_back(to_generic(opcodes.GetU16(&offset))); 1269 break; 1270 case DW_OP_const2s: 1271 stack.push_back(to_generic((int16_t)opcodes.GetU16(&offset))); 1272 break; 1273 case DW_OP_const4u: 1274 stack.push_back(to_generic(opcodes.GetU32(&offset))); 1275 break; 1276 case DW_OP_const4s: 1277 stack.push_back(to_generic((int32_t)opcodes.GetU32(&offset))); 1278 break; 1279 case DW_OP_const8u: 1280 stack.push_back(to_generic(opcodes.GetU64(&offset))); 1281 break; 1282 case DW_OP_const8s: 1283 stack.push_back(to_generic((int64_t)opcodes.GetU64(&offset))); 1284 break; 1285 // These should also use to_generic, but we can't do that due to a 1286 // producer-side bug in llvm. See llvm.org/pr48087. 1287 case DW_OP_constu: 1288 stack.push_back(Scalar(opcodes.GetULEB128(&offset))); 1289 break; 1290 case DW_OP_consts: 1291 stack.push_back(Scalar(opcodes.GetSLEB128(&offset))); 1292 break; 1293 1294 // OPCODE: DW_OP_dup 1295 // OPERANDS: none 1296 // DESCRIPTION: duplicates the value at the top of the stack 1297 case DW_OP_dup: 1298 if (stack.empty()) { 1299 return llvm::createStringError("expression stack empty for DW_OP_dup"); 1300 } else 1301 stack.push_back(stack.back()); 1302 break; 1303 1304 // OPCODE: DW_OP_drop 1305 // OPERANDS: none 1306 // DESCRIPTION: pops the value at the top of the stack 1307 case DW_OP_drop: 1308 if (stack.empty()) { 1309 return llvm::createStringError("expression stack empty for DW_OP_drop"); 1310 } else 1311 stack.pop_back(); 1312 break; 1313 1314 // OPCODE: DW_OP_over 1315 // OPERANDS: none 1316 // DESCRIPTION: Duplicates the entry currently second in the stack at 1317 // the top of the stack. 1318 case DW_OP_over: 1319 stack.push_back(stack[stack.size() - 2]); 1320 break; 1321 1322 // OPCODE: DW_OP_pick 1323 // OPERANDS: uint8_t index into the current stack 1324 // DESCRIPTION: The stack entry with the specified index (0 through 255, 1325 // inclusive) is pushed on the stack 1326 case DW_OP_pick: { 1327 uint8_t pick_idx = opcodes.GetU8(&offset); 1328 if (pick_idx < stack.size()) 1329 stack.push_back(stack[stack.size() - 1 - pick_idx]); 1330 else { 1331 return llvm::createStringError( 1332 "Index %u out of range for DW_OP_pick.\n", pick_idx); 1333 } 1334 } break; 1335 1336 // OPCODE: DW_OP_swap 1337 // OPERANDS: none 1338 // DESCRIPTION: swaps the top two stack entries. The entry at the top 1339 // of the stack becomes the second stack entry, and the second entry 1340 // becomes the top of the stack 1341 case DW_OP_swap: 1342 tmp = stack.back(); 1343 stack.back() = stack[stack.size() - 2]; 1344 stack[stack.size() - 2] = tmp; 1345 break; 1346 1347 // OPCODE: DW_OP_rot 1348 // OPERANDS: none 1349 // DESCRIPTION: Rotates the first three stack entries. The entry at 1350 // the top of the stack becomes the third stack entry, the second entry 1351 // becomes the top of the stack, and the third entry becomes the second 1352 // entry. 1353 case DW_OP_rot: { 1354 size_t last_idx = stack.size() - 1; 1355 Value old_top = stack[last_idx]; 1356 stack[last_idx] = stack[last_idx - 1]; 1357 stack[last_idx - 1] = stack[last_idx - 2]; 1358 stack[last_idx - 2] = old_top; 1359 } break; 1360 1361 // OPCODE: DW_OP_abs 1362 // OPERANDS: none 1363 // DESCRIPTION: pops the top stack entry, interprets it as a signed 1364 // value and pushes its absolute value. If the absolute value can not be 1365 // represented, the result is undefined. 1366 case DW_OP_abs: 1367 if (!stack.back().ResolveValue(exe_ctx).AbsoluteValue()) { 1368 return llvm::createStringError( 1369 "failed to take the absolute value of the first stack item"); 1370 } 1371 break; 1372 1373 // OPCODE: DW_OP_and 1374 // OPERANDS: none 1375 // DESCRIPTION: pops the top two stack values, performs a bitwise and 1376 // operation on the two, and pushes the result. 1377 case DW_OP_and: 1378 tmp = stack.back(); 1379 stack.pop_back(); 1380 stack.back().ResolveValue(exe_ctx) = 1381 stack.back().ResolveValue(exe_ctx) & tmp.ResolveValue(exe_ctx); 1382 break; 1383 1384 // OPCODE: DW_OP_div 1385 // OPERANDS: none 1386 // DESCRIPTION: pops the top two stack values, divides the former second 1387 // entry by the former top of the stack using signed division, and pushes 1388 // the result. 1389 case DW_OP_div: { 1390 tmp = stack.back(); 1391 if (tmp.ResolveValue(exe_ctx).IsZero()) 1392 return llvm::createStringError("divide by zero"); 1393 1394 stack.pop_back(); 1395 Scalar divisor, dividend; 1396 divisor = tmp.ResolveValue(exe_ctx); 1397 dividend = stack.back().ResolveValue(exe_ctx); 1398 divisor.MakeSigned(); 1399 dividend.MakeSigned(); 1400 stack.back() = dividend / divisor; 1401 1402 if (!stack.back().ResolveValue(exe_ctx).IsValid()) 1403 return llvm::createStringError("divide failed"); 1404 } break; 1405 1406 // OPCODE: DW_OP_minus 1407 // OPERANDS: none 1408 // DESCRIPTION: pops the top two stack values, subtracts the former top 1409 // of the stack from the former second entry, and pushes the result. 1410 case DW_OP_minus: 1411 tmp = stack.back(); 1412 stack.pop_back(); 1413 stack.back().ResolveValue(exe_ctx) = 1414 stack.back().ResolveValue(exe_ctx) - tmp.ResolveValue(exe_ctx); 1415 break; 1416 1417 // OPCODE: DW_OP_mod 1418 // OPERANDS: none 1419 // DESCRIPTION: pops the top two stack values and pushes the result of 1420 // the calculation: former second stack entry modulo the former top of the 1421 // stack. 1422 case DW_OP_mod: 1423 tmp = stack.back(); 1424 stack.pop_back(); 1425 stack.back().ResolveValue(exe_ctx) = 1426 stack.back().ResolveValue(exe_ctx) % tmp.ResolveValue(exe_ctx); 1427 break; 1428 1429 // OPCODE: DW_OP_mul 1430 // OPERANDS: none 1431 // DESCRIPTION: pops the top two stack entries, multiplies them 1432 // together, and pushes the result. 1433 case DW_OP_mul: 1434 tmp = stack.back(); 1435 stack.pop_back(); 1436 stack.back().ResolveValue(exe_ctx) = 1437 stack.back().ResolveValue(exe_ctx) * tmp.ResolveValue(exe_ctx); 1438 break; 1439 1440 // OPCODE: DW_OP_neg 1441 // OPERANDS: none 1442 // DESCRIPTION: pops the top stack entry, and pushes its negation. 1443 case DW_OP_neg: 1444 if (!stack.back().ResolveValue(exe_ctx).UnaryNegate()) 1445 return llvm::createStringError("unary negate failed"); 1446 break; 1447 1448 // OPCODE: DW_OP_not 1449 // OPERANDS: none 1450 // DESCRIPTION: pops the top stack entry, and pushes its bitwise 1451 // complement 1452 case DW_OP_not: 1453 if (!stack.back().ResolveValue(exe_ctx).OnesComplement()) 1454 return llvm::createStringError("logical NOT failed"); 1455 break; 1456 1457 // OPCODE: DW_OP_or 1458 // OPERANDS: none 1459 // DESCRIPTION: pops the top two stack entries, performs a bitwise or 1460 // operation on the two, and pushes the result. 1461 case DW_OP_or: 1462 tmp = stack.back(); 1463 stack.pop_back(); 1464 stack.back().ResolveValue(exe_ctx) = 1465 stack.back().ResolveValue(exe_ctx) | tmp.ResolveValue(exe_ctx); 1466 break; 1467 1468 // OPCODE: DW_OP_plus 1469 // OPERANDS: none 1470 // DESCRIPTION: pops the top two stack entries, adds them together, and 1471 // pushes the result. 1472 case DW_OP_plus: 1473 tmp = stack.back(); 1474 stack.pop_back(); 1475 stack.back().GetScalar() += tmp.GetScalar(); 1476 break; 1477 1478 // OPCODE: DW_OP_plus_uconst 1479 // OPERANDS: none 1480 // DESCRIPTION: pops the top stack entry, adds it to the unsigned LEB128 1481 // constant operand and pushes the result. 1482 case DW_OP_plus_uconst: { 1483 const uint64_t uconst_value = opcodes.GetULEB128(&offset); 1484 // Implicit conversion from a UINT to a Scalar... 1485 stack.back().GetScalar() += uconst_value; 1486 if (!stack.back().GetScalar().IsValid()) 1487 return llvm::createStringError("DW_OP_plus_uconst failed"); 1488 } break; 1489 1490 // OPCODE: DW_OP_shl 1491 // OPERANDS: none 1492 // DESCRIPTION: pops the top two stack entries, shifts the former 1493 // second entry left by the number of bits specified by the former top of 1494 // the stack, and pushes the result. 1495 case DW_OP_shl: 1496 tmp = stack.back(); 1497 stack.pop_back(); 1498 stack.back().ResolveValue(exe_ctx) <<= tmp.ResolveValue(exe_ctx); 1499 break; 1500 1501 // OPCODE: DW_OP_shr 1502 // OPERANDS: none 1503 // DESCRIPTION: pops the top two stack entries, shifts the former second 1504 // entry right logically (filling with zero bits) by the number of bits 1505 // specified by the former top of the stack, and pushes the result. 1506 case DW_OP_shr: 1507 tmp = stack.back(); 1508 stack.pop_back(); 1509 if (!stack.back().ResolveValue(exe_ctx).ShiftRightLogical( 1510 tmp.ResolveValue(exe_ctx))) 1511 return llvm::createStringError("DW_OP_shr failed"); 1512 break; 1513 1514 // OPCODE: DW_OP_shra 1515 // OPERANDS: none 1516 // DESCRIPTION: pops the top two stack entries, shifts the former second 1517 // entry right arithmetically (divide the magnitude by 2, keep the same 1518 // sign for the result) by the number of bits specified by the former top 1519 // of the stack, and pushes the result. 1520 case DW_OP_shra: 1521 tmp = stack.back(); 1522 stack.pop_back(); 1523 stack.back().ResolveValue(exe_ctx) >>= tmp.ResolveValue(exe_ctx); 1524 break; 1525 1526 // OPCODE: DW_OP_xor 1527 // OPERANDS: none 1528 // DESCRIPTION: pops the top two stack entries, performs the bitwise 1529 // exclusive-or operation on the two, and pushes the result. 1530 case DW_OP_xor: 1531 tmp = stack.back(); 1532 stack.pop_back(); 1533 stack.back().ResolveValue(exe_ctx) = 1534 stack.back().ResolveValue(exe_ctx) ^ tmp.ResolveValue(exe_ctx); 1535 break; 1536 1537 // OPCODE: DW_OP_skip 1538 // OPERANDS: int16_t 1539 // DESCRIPTION: An unconditional branch. Its single operand is a 2-byte 1540 // signed integer constant. The 2-byte constant is the number of bytes of 1541 // the DWARF expression to skip forward or backward from the current 1542 // operation, beginning after the 2-byte constant. 1543 case DW_OP_skip: { 1544 int16_t skip_offset = (int16_t)opcodes.GetU16(&offset); 1545 lldb::offset_t new_offset = offset + skip_offset; 1546 // New offset can point at the end of the data, in this case we should 1547 // terminate the DWARF expression evaluation (will happen in the loop 1548 // condition). 1549 if (new_offset <= opcodes.GetByteSize()) 1550 offset = new_offset; 1551 else { 1552 return llvm::createStringError(llvm::formatv( 1553 "Invalid opcode offset in DW_OP_skip: {0}+({1}) > {2}", offset, 1554 skip_offset, opcodes.GetByteSize())); 1555 } 1556 } break; 1557 1558 // OPCODE: DW_OP_bra 1559 // OPERANDS: int16_t 1560 // DESCRIPTION: A conditional branch. Its single operand is a 2-byte 1561 // signed integer constant. This operation pops the top of stack. If the 1562 // value popped is not the constant 0, the 2-byte constant operand is the 1563 // number of bytes of the DWARF expression to skip forward or backward from 1564 // the current operation, beginning after the 2-byte constant. 1565 case DW_OP_bra: { 1566 tmp = stack.back(); 1567 stack.pop_back(); 1568 int16_t bra_offset = (int16_t)opcodes.GetU16(&offset); 1569 Scalar zero(0); 1570 if (tmp.ResolveValue(exe_ctx) != zero) { 1571 lldb::offset_t new_offset = offset + bra_offset; 1572 // New offset can point at the end of the data, in this case we should 1573 // terminate the DWARF expression evaluation (will happen in the loop 1574 // condition). 1575 if (new_offset <= opcodes.GetByteSize()) 1576 offset = new_offset; 1577 else { 1578 return llvm::createStringError(llvm::formatv( 1579 "Invalid opcode offset in DW_OP_bra: {0}+({1}) > {2}", offset, 1580 bra_offset, opcodes.GetByteSize())); 1581 } 1582 } 1583 } break; 1584 1585 // OPCODE: DW_OP_eq 1586 // OPERANDS: none 1587 // DESCRIPTION: pops the top two stack values, compares using the 1588 // equals (==) operator. 1589 // STACK RESULT: push the constant value 1 onto the stack if the result 1590 // of the operation is true or the constant value 0 if the result of the 1591 // operation is false. 1592 case DW_OP_eq: 1593 tmp = stack.back(); 1594 stack.pop_back(); 1595 stack.back().ResolveValue(exe_ctx) = 1596 stack.back().ResolveValue(exe_ctx) == tmp.ResolveValue(exe_ctx); 1597 break; 1598 1599 // OPCODE: DW_OP_ge 1600 // OPERANDS: none 1601 // DESCRIPTION: pops the top two stack values, compares using the 1602 // greater than or equal to (>=) operator. 1603 // STACK RESULT: push the constant value 1 onto the stack if the result 1604 // of the operation is true or the constant value 0 if the result of the 1605 // operation is false. 1606 case DW_OP_ge: 1607 tmp = stack.back(); 1608 stack.pop_back(); 1609 stack.back().ResolveValue(exe_ctx) = 1610 stack.back().ResolveValue(exe_ctx) >= tmp.ResolveValue(exe_ctx); 1611 break; 1612 1613 // OPCODE: DW_OP_gt 1614 // OPERANDS: none 1615 // DESCRIPTION: pops the top two stack values, compares using the 1616 // greater than (>) operator. 1617 // STACK RESULT: push the constant value 1 onto the stack if the result 1618 // of the operation is true or the constant value 0 if the result of the 1619 // operation is false. 1620 case DW_OP_gt: 1621 tmp = stack.back(); 1622 stack.pop_back(); 1623 stack.back().ResolveValue(exe_ctx) = 1624 stack.back().ResolveValue(exe_ctx) > tmp.ResolveValue(exe_ctx); 1625 break; 1626 1627 // OPCODE: DW_OP_le 1628 // OPERANDS: none 1629 // DESCRIPTION: pops the top two stack values, compares using the 1630 // less than or equal to (<=) operator. 1631 // STACK RESULT: push the constant value 1 onto the stack if the result 1632 // of the operation is true or the constant value 0 if the result of the 1633 // operation is false. 1634 case DW_OP_le: 1635 tmp = stack.back(); 1636 stack.pop_back(); 1637 stack.back().ResolveValue(exe_ctx) = 1638 stack.back().ResolveValue(exe_ctx) <= tmp.ResolveValue(exe_ctx); 1639 break; 1640 1641 // OPCODE: DW_OP_lt 1642 // OPERANDS: none 1643 // DESCRIPTION: pops the top two stack values, compares using the 1644 // less than (<) operator. 1645 // STACK RESULT: push the constant value 1 onto the stack if the result 1646 // of the operation is true or the constant value 0 if the result of the 1647 // operation is false. 1648 case DW_OP_lt: 1649 tmp = stack.back(); 1650 stack.pop_back(); 1651 stack.back().ResolveValue(exe_ctx) = 1652 stack.back().ResolveValue(exe_ctx) < tmp.ResolveValue(exe_ctx); 1653 break; 1654 1655 // OPCODE: DW_OP_ne 1656 // OPERANDS: none 1657 // DESCRIPTION: pops the top two stack values, compares using the 1658 // not equal (!=) operator. 1659 // STACK RESULT: push the constant value 1 onto the stack if the result 1660 // of the operation is true or the constant value 0 if the result of the 1661 // operation is false. 1662 case DW_OP_ne: 1663 tmp = stack.back(); 1664 stack.pop_back(); 1665 stack.back().ResolveValue(exe_ctx) = 1666 stack.back().ResolveValue(exe_ctx) != tmp.ResolveValue(exe_ctx); 1667 break; 1668 1669 // OPCODE: DW_OP_litn 1670 // OPERANDS: none 1671 // DESCRIPTION: encode the unsigned literal values from 0 through 31. 1672 // STACK RESULT: push the unsigned literal constant value onto the top 1673 // of the stack. 1674 case DW_OP_lit0: 1675 case DW_OP_lit1: 1676 case DW_OP_lit2: 1677 case DW_OP_lit3: 1678 case DW_OP_lit4: 1679 case DW_OP_lit5: 1680 case DW_OP_lit6: 1681 case DW_OP_lit7: 1682 case DW_OP_lit8: 1683 case DW_OP_lit9: 1684 case DW_OP_lit10: 1685 case DW_OP_lit11: 1686 case DW_OP_lit12: 1687 case DW_OP_lit13: 1688 case DW_OP_lit14: 1689 case DW_OP_lit15: 1690 case DW_OP_lit16: 1691 case DW_OP_lit17: 1692 case DW_OP_lit18: 1693 case DW_OP_lit19: 1694 case DW_OP_lit20: 1695 case DW_OP_lit21: 1696 case DW_OP_lit22: 1697 case DW_OP_lit23: 1698 case DW_OP_lit24: 1699 case DW_OP_lit25: 1700 case DW_OP_lit26: 1701 case DW_OP_lit27: 1702 case DW_OP_lit28: 1703 case DW_OP_lit29: 1704 case DW_OP_lit30: 1705 case DW_OP_lit31: 1706 stack.push_back(to_generic(op - DW_OP_lit0)); 1707 break; 1708 1709 // OPCODE: DW_OP_regN 1710 // OPERANDS: none 1711 // DESCRIPTION: Push the value in register n on the top of the stack. 1712 case DW_OP_reg0: 1713 case DW_OP_reg1: 1714 case DW_OP_reg2: 1715 case DW_OP_reg3: 1716 case DW_OP_reg4: 1717 case DW_OP_reg5: 1718 case DW_OP_reg6: 1719 case DW_OP_reg7: 1720 case DW_OP_reg8: 1721 case DW_OP_reg9: 1722 case DW_OP_reg10: 1723 case DW_OP_reg11: 1724 case DW_OP_reg12: 1725 case DW_OP_reg13: 1726 case DW_OP_reg14: 1727 case DW_OP_reg15: 1728 case DW_OP_reg16: 1729 case DW_OP_reg17: 1730 case DW_OP_reg18: 1731 case DW_OP_reg19: 1732 case DW_OP_reg20: 1733 case DW_OP_reg21: 1734 case DW_OP_reg22: 1735 case DW_OP_reg23: 1736 case DW_OP_reg24: 1737 case DW_OP_reg25: 1738 case DW_OP_reg26: 1739 case DW_OP_reg27: 1740 case DW_OP_reg28: 1741 case DW_OP_reg29: 1742 case DW_OP_reg30: 1743 case DW_OP_reg31: { 1744 dwarf4_location_description_kind = Register; 1745 reg_num = op - DW_OP_reg0; 1746 1747 if (llvm::Error err = 1748 ReadRegisterValueAsScalar(reg_ctx, reg_kind, reg_num, tmp)) 1749 return err; 1750 stack.push_back(tmp); 1751 } break; 1752 // OPCODE: DW_OP_regx 1753 // OPERANDS: 1754 // ULEB128 literal operand that encodes the register. 1755 // DESCRIPTION: Push the value in register on the top of the stack. 1756 case DW_OP_regx: { 1757 dwarf4_location_description_kind = Register; 1758 reg_num = opcodes.GetULEB128(&offset); 1759 Status read_err; 1760 if (llvm::Error err = 1761 ReadRegisterValueAsScalar(reg_ctx, reg_kind, reg_num, tmp)) 1762 return err; 1763 stack.push_back(tmp); 1764 } break; 1765 1766 // OPCODE: DW_OP_bregN 1767 // OPERANDS: 1768 // SLEB128 offset from register N 1769 // DESCRIPTION: Value is in memory at the address specified by register 1770 // N plus an offset. 1771 case DW_OP_breg0: 1772 case DW_OP_breg1: 1773 case DW_OP_breg2: 1774 case DW_OP_breg3: 1775 case DW_OP_breg4: 1776 case DW_OP_breg5: 1777 case DW_OP_breg6: 1778 case DW_OP_breg7: 1779 case DW_OP_breg8: 1780 case DW_OP_breg9: 1781 case DW_OP_breg10: 1782 case DW_OP_breg11: 1783 case DW_OP_breg12: 1784 case DW_OP_breg13: 1785 case DW_OP_breg14: 1786 case DW_OP_breg15: 1787 case DW_OP_breg16: 1788 case DW_OP_breg17: 1789 case DW_OP_breg18: 1790 case DW_OP_breg19: 1791 case DW_OP_breg20: 1792 case DW_OP_breg21: 1793 case DW_OP_breg22: 1794 case DW_OP_breg23: 1795 case DW_OP_breg24: 1796 case DW_OP_breg25: 1797 case DW_OP_breg26: 1798 case DW_OP_breg27: 1799 case DW_OP_breg28: 1800 case DW_OP_breg29: 1801 case DW_OP_breg30: 1802 case DW_OP_breg31: { 1803 reg_num = op - DW_OP_breg0; 1804 if (llvm::Error err = 1805 ReadRegisterValueAsScalar(reg_ctx, reg_kind, reg_num, tmp)) 1806 return err; 1807 1808 int64_t breg_offset = opcodes.GetSLEB128(&offset); 1809 tmp.ResolveValue(exe_ctx) += (uint64_t)breg_offset; 1810 tmp.ClearContext(); 1811 stack.push_back(tmp); 1812 stack.back().SetValueType(Value::ValueType::LoadAddress); 1813 } break; 1814 // OPCODE: DW_OP_bregx 1815 // OPERANDS: 2 1816 // ULEB128 literal operand that encodes the register. 1817 // SLEB128 offset from register N 1818 // DESCRIPTION: Value is in memory at the address specified by register 1819 // N plus an offset. 1820 case DW_OP_bregx: { 1821 reg_num = opcodes.GetULEB128(&offset); 1822 if (llvm::Error err = 1823 ReadRegisterValueAsScalar(reg_ctx, reg_kind, reg_num, tmp)) 1824 return err; 1825 1826 int64_t breg_offset = opcodes.GetSLEB128(&offset); 1827 tmp.ResolveValue(exe_ctx) += (uint64_t)breg_offset; 1828 tmp.ClearContext(); 1829 stack.push_back(tmp); 1830 stack.back().SetValueType(Value::ValueType::LoadAddress); 1831 } break; 1832 1833 case DW_OP_fbreg: 1834 if (exe_ctx) { 1835 if (frame) { 1836 Scalar value; 1837 if (llvm::Error err = frame->GetFrameBaseValue(value)) 1838 return err; 1839 int64_t fbreg_offset = opcodes.GetSLEB128(&offset); 1840 value += fbreg_offset; 1841 stack.push_back(value); 1842 stack.back().SetValueType(Value::ValueType::LoadAddress); 1843 } else { 1844 return llvm::createStringError( 1845 "invalid stack frame in context for DW_OP_fbreg opcode"); 1846 } 1847 } else { 1848 return llvm::createStringError( 1849 "NULL execution context for DW_OP_fbreg"); 1850 } 1851 1852 break; 1853 1854 // OPCODE: DW_OP_nop 1855 // OPERANDS: none 1856 // DESCRIPTION: A place holder. It has no effect on the location stack 1857 // or any of its values. 1858 case DW_OP_nop: 1859 break; 1860 1861 // OPCODE: DW_OP_piece 1862 // OPERANDS: 1 1863 // ULEB128: byte size of the piece 1864 // DESCRIPTION: The operand describes the size in bytes of the piece of 1865 // the object referenced by the DWARF expression whose result is at the top 1866 // of the stack. If the piece is located in a register, but does not occupy 1867 // the entire register, the placement of the piece within that register is 1868 // defined by the ABI. 1869 // 1870 // Many compilers store a single variable in sets of registers, or store a 1871 // variable partially in memory and partially in registers. DW_OP_piece 1872 // provides a way of describing how large a part of a variable a particular 1873 // DWARF expression refers to. 1874 case DW_OP_piece: { 1875 LocationDescriptionKind piece_locdesc = dwarf4_location_description_kind; 1876 // Reset for the next piece. 1877 dwarf4_location_description_kind = Memory; 1878 1879 const uint64_t piece_byte_size = opcodes.GetULEB128(&offset); 1880 1881 if (piece_byte_size > 0) { 1882 Value curr_piece; 1883 1884 if (stack.empty()) { 1885 UpdateValueTypeFromLocationDescription( 1886 log, dwarf_cu, LocationDescriptionKind::Empty); 1887 // In a multi-piece expression, this means that the current piece is 1888 // not available. Fill with zeros for now by resizing the data and 1889 // appending it 1890 curr_piece.ResizeData(piece_byte_size); 1891 // Note that "0" is not a correct value for the unknown bits. 1892 // It would be better to also return a mask of valid bits together 1893 // with the expression result, so the debugger can print missing 1894 // members as "<optimized out>" or something. 1895 ::memset(curr_piece.GetBuffer().GetBytes(), 0, piece_byte_size); 1896 pieces.AppendDataToHostBuffer(curr_piece); 1897 } else { 1898 Status error; 1899 // Extract the current piece into "curr_piece" 1900 Value curr_piece_source_value(stack.back()); 1901 stack.pop_back(); 1902 UpdateValueTypeFromLocationDescription(log, dwarf_cu, piece_locdesc, 1903 &curr_piece_source_value); 1904 1905 const Value::ValueType curr_piece_source_value_type = 1906 curr_piece_source_value.GetValueType(); 1907 Scalar &scalar = curr_piece_source_value.GetScalar(); 1908 lldb::addr_t addr = scalar.ULongLong(LLDB_INVALID_ADDRESS); 1909 switch (curr_piece_source_value_type) { 1910 case Value::ValueType::Invalid: 1911 return llvm::createStringError("invalid value type"); 1912 case Value::ValueType::FileAddress: 1913 if (target) { 1914 curr_piece_source_value.ConvertToLoadAddress(module_sp.get(), 1915 target); 1916 addr = scalar.ULongLong(LLDB_INVALID_ADDRESS); 1917 } else { 1918 return llvm::createStringError( 1919 "unable to convert file address 0x%" PRIx64 1920 " to load address " 1921 "for DW_OP_piece(%" PRIu64 "): " 1922 "no target available", 1923 addr, piece_byte_size); 1924 } 1925 [[fallthrough]]; 1926 case Value::ValueType::LoadAddress: { 1927 if (target) { 1928 if (curr_piece.ResizeData(piece_byte_size) == piece_byte_size) { 1929 if (target->ReadMemory(addr, curr_piece.GetBuffer().GetBytes(), 1930 piece_byte_size, error, 1931 /*force_live_memory=*/false) != 1932 piece_byte_size) { 1933 const char *addr_type = (curr_piece_source_value_type == 1934 Value::ValueType::LoadAddress) 1935 ? "load" 1936 : "file"; 1937 return llvm::createStringError( 1938 "failed to read memory DW_OP_piece(%" PRIu64 1939 ") from %s address 0x%" PRIx64, 1940 piece_byte_size, addr_type, addr); 1941 } 1942 } else { 1943 return llvm::createStringError( 1944 "failed to resize the piece memory buffer for " 1945 "DW_OP_piece(%" PRIu64 ")", 1946 piece_byte_size); 1947 } 1948 } 1949 } break; 1950 case Value::ValueType::HostAddress: { 1951 return llvm::createStringError( 1952 "failed to read memory DW_OP_piece(%" PRIu64 1953 ") from host address 0x%" PRIx64, 1954 piece_byte_size, addr); 1955 } break; 1956 1957 case Value::ValueType::Scalar: { 1958 uint32_t bit_size = piece_byte_size * 8; 1959 uint32_t bit_offset = 0; 1960 if (!scalar.ExtractBitfield( 1961 bit_size, bit_offset)) { 1962 return llvm::createStringError( 1963 "unable to extract %" PRIu64 " bytes from a %" PRIu64 1964 " byte scalar value.", 1965 piece_byte_size, 1966 (uint64_t)curr_piece_source_value.GetScalar().GetByteSize()); 1967 } 1968 // Create curr_piece with bit_size. By default Scalar 1969 // grows to the nearest host integer type. 1970 llvm::APInt fail_value(1, 0, false); 1971 llvm::APInt ap_int = scalar.UInt128(fail_value); 1972 assert(ap_int.getBitWidth() >= bit_size); 1973 llvm::ArrayRef<uint64_t> buf{ap_int.getRawData(), 1974 ap_int.getNumWords()}; 1975 curr_piece.GetScalar() = Scalar(llvm::APInt(bit_size, buf)); 1976 } break; 1977 } 1978 1979 // Check if this is the first piece? 1980 if (op_piece_offset == 0) { 1981 // This is the first piece, we should push it back onto the stack 1982 // so subsequent pieces will be able to access this piece and add 1983 // to it. 1984 if (pieces.AppendDataToHostBuffer(curr_piece) == 0) { 1985 return llvm::createStringError("failed to append piece data"); 1986 } 1987 } else { 1988 // If this is the second or later piece there should be a value on 1989 // the stack. 1990 if (pieces.GetBuffer().GetByteSize() != op_piece_offset) { 1991 return llvm::createStringError( 1992 "DW_OP_piece for offset %" PRIu64 1993 " but top of stack is of size %" PRIu64, 1994 op_piece_offset, pieces.GetBuffer().GetByteSize()); 1995 } 1996 1997 if (pieces.AppendDataToHostBuffer(curr_piece) == 0) 1998 return llvm::createStringError("failed to append piece data"); 1999 } 2000 } 2001 op_piece_offset += piece_byte_size; 2002 } 2003 } break; 2004 2005 case DW_OP_bit_piece: // 0x9d ULEB128 bit size, ULEB128 bit offset (DWARF3); 2006 if (stack.size() < 1) { 2007 UpdateValueTypeFromLocationDescription(log, dwarf_cu, 2008 LocationDescriptionKind::Empty); 2009 // Reset for the next piece. 2010 dwarf4_location_description_kind = Memory; 2011 return llvm::createStringError( 2012 "expression stack needs at least 1 item for DW_OP_bit_piece"); 2013 } else { 2014 UpdateValueTypeFromLocationDescription( 2015 log, dwarf_cu, dwarf4_location_description_kind, &stack.back()); 2016 // Reset for the next piece. 2017 dwarf4_location_description_kind = Memory; 2018 const uint64_t piece_bit_size = opcodes.GetULEB128(&offset); 2019 const uint64_t piece_bit_offset = opcodes.GetULEB128(&offset); 2020 switch (stack.back().GetValueType()) { 2021 case Value::ValueType::Invalid: 2022 return llvm::createStringError( 2023 "unable to extract bit value from invalid value"); 2024 case Value::ValueType::Scalar: { 2025 if (!stack.back().GetScalar().ExtractBitfield(piece_bit_size, 2026 piece_bit_offset)) { 2027 return llvm::createStringError( 2028 "unable to extract %" PRIu64 " bit value with %" PRIu64 2029 " bit offset from a %" PRIu64 " bit scalar value.", 2030 piece_bit_size, piece_bit_offset, 2031 (uint64_t)(stack.back().GetScalar().GetByteSize() * 8)); 2032 } 2033 } break; 2034 2035 case Value::ValueType::FileAddress: 2036 case Value::ValueType::LoadAddress: 2037 case Value::ValueType::HostAddress: 2038 return llvm::createStringError( 2039 "unable to extract DW_OP_bit_piece(bit_size = %" PRIu64 2040 ", bit_offset = %" PRIu64 ") from an address value.", 2041 piece_bit_size, piece_bit_offset); 2042 } 2043 } 2044 break; 2045 2046 // OPCODE: DW_OP_implicit_value 2047 // OPERANDS: 2 2048 // ULEB128 size of the value block in bytes 2049 // uint8_t* block bytes encoding value in target's memory 2050 // representation 2051 // DESCRIPTION: Value is immediately stored in block in the debug info with 2052 // the memory representation of the target. 2053 case DW_OP_implicit_value: { 2054 dwarf4_location_description_kind = Implicit; 2055 2056 const uint32_t len = opcodes.GetULEB128(&offset); 2057 const void *data = opcodes.GetData(&offset, len); 2058 2059 if (!data) { 2060 LLDB_LOG(log, "Evaluate_DW_OP_implicit_value: could not be read data"); 2061 return llvm::createStringError("could not evaluate %s", 2062 DW_OP_value_to_name(op)); 2063 } 2064 2065 Value result(data, len); 2066 stack.push_back(result); 2067 break; 2068 } 2069 2070 case DW_OP_implicit_pointer: { 2071 dwarf4_location_description_kind = Implicit; 2072 return llvm::createStringError("Could not evaluate %s.", 2073 DW_OP_value_to_name(op)); 2074 } 2075 2076 // OPCODE: DW_OP_push_object_address 2077 // OPERANDS: none 2078 // DESCRIPTION: Pushes the address of the object currently being 2079 // evaluated as part of evaluation of a user presented expression. This 2080 // object may correspond to an independent variable described by its own 2081 // DIE or it may be a component of an array, structure, or class whose 2082 // address has been dynamically determined by an earlier step during user 2083 // expression evaluation. 2084 case DW_OP_push_object_address: 2085 if (object_address_ptr) 2086 stack.push_back(*object_address_ptr); 2087 else { 2088 return llvm::createStringError("DW_OP_push_object_address used without " 2089 "specifying an object address"); 2090 } 2091 break; 2092 2093 // OPCODE: DW_OP_call2 2094 // OPERANDS: 2095 // uint16_t compile unit relative offset of a DIE 2096 // DESCRIPTION: Performs subroutine calls during evaluation 2097 // of a DWARF expression. The operand is the 2-byte unsigned offset of a 2098 // debugging information entry in the current compilation unit. 2099 // 2100 // Operand interpretation is exactly like that for DW_FORM_ref2. 2101 // 2102 // This operation transfers control of DWARF expression evaluation to the 2103 // DW_AT_location attribute of the referenced DIE. If there is no such 2104 // attribute, then there is no effect. Execution of the DWARF expression of 2105 // a DW_AT_location attribute may add to and/or remove from values on the 2106 // stack. Execution returns to the point following the call when the end of 2107 // the attribute is reached. Values on the stack at the time of the call 2108 // may be used as parameters by the called expression and values left on 2109 // the stack by the called expression may be used as return values by prior 2110 // agreement between the calling and called expressions. 2111 case DW_OP_call2: 2112 return llvm::createStringError("unimplemented opcode DW_OP_call2"); 2113 // OPCODE: DW_OP_call4 2114 // OPERANDS: 1 2115 // uint32_t compile unit relative offset of a DIE 2116 // DESCRIPTION: Performs a subroutine call during evaluation of a DWARF 2117 // expression. For DW_OP_call4, the operand is a 4-byte unsigned offset of 2118 // a debugging information entry in the current compilation unit. 2119 // 2120 // Operand interpretation DW_OP_call4 is exactly like that for 2121 // DW_FORM_ref4. 2122 // 2123 // This operation transfers control of DWARF expression evaluation to the 2124 // DW_AT_location attribute of the referenced DIE. If there is no such 2125 // attribute, then there is no effect. Execution of the DWARF expression of 2126 // a DW_AT_location attribute may add to and/or remove from values on the 2127 // stack. Execution returns to the point following the call when the end of 2128 // the attribute is reached. Values on the stack at the time of the call 2129 // may be used as parameters by the called expression and values left on 2130 // the stack by the called expression may be used as return values by prior 2131 // agreement between the calling and called expressions. 2132 case DW_OP_call4: 2133 return llvm::createStringError("unimplemented opcode DW_OP_call4"); 2134 2135 // OPCODE: DW_OP_stack_value 2136 // OPERANDS: None 2137 // DESCRIPTION: Specifies that the object does not exist in memory but 2138 // rather is a constant value. The value from the top of the stack is the 2139 // value to be used. This is the actual object value and not the location. 2140 case DW_OP_stack_value: 2141 dwarf4_location_description_kind = Implicit; 2142 stack.back().SetValueType(Value::ValueType::Scalar); 2143 break; 2144 2145 // OPCODE: DW_OP_convert 2146 // OPERANDS: 1 2147 // A ULEB128 that is either a DIE offset of a 2148 // DW_TAG_base_type or 0 for the generic (pointer-sized) type. 2149 // 2150 // DESCRIPTION: Pop the top stack element, convert it to a 2151 // different type, and push the result. 2152 case DW_OP_convert: { 2153 const uint64_t die_offset = opcodes.GetULEB128(&offset); 2154 uint64_t bit_size; 2155 bool sign; 2156 if (die_offset == 0) { 2157 // The generic type has the size of an address on the target 2158 // machine and an unspecified signedness. Scalar has no 2159 // "unspecified signedness", so we use unsigned types. 2160 if (!module_sp) 2161 return llvm::createStringError("no module"); 2162 sign = false; 2163 bit_size = module_sp->GetArchitecture().GetAddressByteSize() * 8; 2164 if (!bit_size) 2165 return llvm::createStringError("unspecified architecture"); 2166 } else { 2167 // Retrieve the type DIE that the value is being converted to. This 2168 // offset is compile unit relative so we need to fix it up. 2169 const uint64_t abs_die_offset = die_offset + dwarf_cu->GetOffset(); 2170 // FIXME: the constness has annoying ripple effects. 2171 DWARFDIE die = const_cast<DWARFUnit *>(dwarf_cu)->GetDIE(abs_die_offset); 2172 if (!die) 2173 return llvm::createStringError( 2174 "cannot resolve DW_OP_convert type DIE"); 2175 uint64_t encoding = 2176 die.GetAttributeValueAsUnsigned(DW_AT_encoding, DW_ATE_hi_user); 2177 bit_size = die.GetAttributeValueAsUnsigned(DW_AT_byte_size, 0) * 8; 2178 if (!bit_size) 2179 bit_size = die.GetAttributeValueAsUnsigned(DW_AT_bit_size, 0); 2180 if (!bit_size) 2181 return llvm::createStringError( 2182 "unsupported type size in DW_OP_convert"); 2183 switch (encoding) { 2184 case DW_ATE_signed: 2185 case DW_ATE_signed_char: 2186 sign = true; 2187 break; 2188 case DW_ATE_unsigned: 2189 case DW_ATE_unsigned_char: 2190 sign = false; 2191 break; 2192 default: 2193 return llvm::createStringError( 2194 "unsupported encoding in DW_OP_convert"); 2195 } 2196 } 2197 Scalar &top = stack.back().ResolveValue(exe_ctx); 2198 top.TruncOrExtendTo(bit_size, sign); 2199 break; 2200 } 2201 2202 // OPCODE: DW_OP_call_frame_cfa 2203 // OPERANDS: None 2204 // DESCRIPTION: Specifies a DWARF expression that pushes the value of 2205 // the canonical frame address consistent with the call frame information 2206 // located in .debug_frame (or in the FDEs of the eh_frame section). 2207 case DW_OP_call_frame_cfa: 2208 if (frame) { 2209 // Note that we don't have to parse FDEs because this DWARF expression 2210 // is commonly evaluated with a valid stack frame. 2211 StackID id = frame->GetStackID(); 2212 addr_t cfa = id.GetCallFrameAddress(); 2213 if (cfa != LLDB_INVALID_ADDRESS) { 2214 stack.push_back(Scalar(cfa)); 2215 stack.back().SetValueType(Value::ValueType::LoadAddress); 2216 } else { 2217 return llvm::createStringError( 2218 "stack frame does not include a canonical " 2219 "frame address for DW_OP_call_frame_cfa " 2220 "opcode"); 2221 } 2222 } else { 2223 return llvm::createStringError("unvalid stack frame in context for " 2224 "DW_OP_call_frame_cfa opcode"); 2225 } 2226 break; 2227 2228 // OPCODE: DW_OP_form_tls_address (or the old pre-DWARFv3 vendor extension 2229 // opcode, DW_OP_GNU_push_tls_address) 2230 // OPERANDS: none 2231 // DESCRIPTION: Pops a TLS offset from the stack, converts it to 2232 // an address in the current thread's thread-local storage block, and 2233 // pushes it on the stack. 2234 case DW_OP_form_tls_address: 2235 case DW_OP_GNU_push_tls_address: { 2236 if (stack.size() < 1) { 2237 if (op == DW_OP_form_tls_address) 2238 return llvm::createStringError( 2239 "DW_OP_form_tls_address needs an argument"); 2240 else 2241 return llvm::createStringError( 2242 "DW_OP_GNU_push_tls_address needs an argument"); 2243 } 2244 2245 if (!exe_ctx || !module_sp) 2246 return llvm::createStringError("no context to evaluate TLS within"); 2247 2248 Thread *thread = exe_ctx->GetThreadPtr(); 2249 if (!thread) 2250 return llvm::createStringError("no thread to evaluate TLS within"); 2251 2252 // Lookup the TLS block address for this thread and module. 2253 const addr_t tls_file_addr = 2254 stack.back().GetScalar().ULongLong(LLDB_INVALID_ADDRESS); 2255 const addr_t tls_load_addr = 2256 thread->GetThreadLocalData(module_sp, tls_file_addr); 2257 2258 if (tls_load_addr == LLDB_INVALID_ADDRESS) 2259 return llvm::createStringError( 2260 "no TLS data currently exists for this thread"); 2261 2262 stack.back().GetScalar() = tls_load_addr; 2263 stack.back().SetValueType(Value::ValueType::LoadAddress); 2264 } break; 2265 2266 // OPCODE: DW_OP_addrx (DW_OP_GNU_addr_index is the legacy name.) 2267 // OPERANDS: 1 2268 // ULEB128: index to the .debug_addr section 2269 // DESCRIPTION: Pushes an address to the stack from the .debug_addr 2270 // section with the base address specified by the DW_AT_addr_base attribute 2271 // and the 0 based index is the ULEB128 encoded index. 2272 case DW_OP_addrx: 2273 case DW_OP_GNU_addr_index: { 2274 if (!dwarf_cu) 2275 return llvm::createStringError("DW_OP_GNU_addr_index found without a " 2276 "compile unit being specified"); 2277 uint64_t index = opcodes.GetULEB128(&offset); 2278 lldb::addr_t value = dwarf_cu->ReadAddressFromDebugAddrSection(index); 2279 stack.push_back(Scalar(value)); 2280 if (target && 2281 target->GetArchitecture().GetCore() == ArchSpec::eCore_wasm32) { 2282 // wasm file sections aren't mapped into memory, therefore addresses can 2283 // never point into a file section and are always LoadAddresses. 2284 stack.back().SetValueType(Value::ValueType::LoadAddress); 2285 } else { 2286 stack.back().SetValueType(Value::ValueType::FileAddress); 2287 } 2288 } break; 2289 2290 // OPCODE: DW_OP_GNU_const_index 2291 // OPERANDS: 1 2292 // ULEB128: index to the .debug_addr section 2293 // DESCRIPTION: Pushes an constant with the size of a machine address to 2294 // the stack from the .debug_addr section with the base address specified 2295 // by the DW_AT_addr_base attribute and the 0 based index is the ULEB128 2296 // encoded index. 2297 case DW_OP_GNU_const_index: { 2298 if (!dwarf_cu) { 2299 return llvm::createStringError("DW_OP_GNU_const_index found without a " 2300 "compile unit being specified"); 2301 } 2302 uint64_t index = opcodes.GetULEB128(&offset); 2303 lldb::addr_t value = dwarf_cu->ReadAddressFromDebugAddrSection(index); 2304 stack.push_back(Scalar(value)); 2305 } break; 2306 2307 case DW_OP_GNU_entry_value: 2308 case DW_OP_entry_value: { 2309 if (llvm::Error err = Evaluate_DW_OP_entry_value(stack, exe_ctx, reg_ctx, 2310 opcodes, offset, log)) 2311 return llvm::createStringError( 2312 "could not evaluate DW_OP_entry_value: %s", 2313 llvm::toString(std::move(err)).c_str()); 2314 break; 2315 } 2316 2317 default: 2318 if (dwarf_cu) { 2319 if (dwarf_cu->GetSymbolFileDWARF().ParseVendorDWARFOpcode( 2320 op, opcodes, offset, stack)) { 2321 break; 2322 } 2323 } 2324 return llvm::createStringError(llvm::formatv( 2325 "Unhandled opcode {0} in DWARFExpression", LocationAtom(op))); 2326 } 2327 } 2328 2329 if (stack.empty()) { 2330 // Nothing on the stack, check if we created a piece value from DW_OP_piece 2331 // or DW_OP_bit_piece opcodes 2332 if (pieces.GetBuffer().GetByteSize()) 2333 return pieces; 2334 2335 return llvm::createStringError("stack empty after evaluation"); 2336 } 2337 2338 UpdateValueTypeFromLocationDescription( 2339 log, dwarf_cu, dwarf4_location_description_kind, &stack.back()); 2340 2341 if (log && log->GetVerbose()) { 2342 size_t count = stack.size(); 2343 LLDB_LOGF(log, 2344 "Stack after operation has %" PRIu64 " values:", (uint64_t)count); 2345 for (size_t i = 0; i < count; ++i) { 2346 StreamString new_value; 2347 new_value.Printf("[%" PRIu64 "]", (uint64_t)i); 2348 stack[i].Dump(&new_value); 2349 LLDB_LOGF(log, " %s", new_value.GetData()); 2350 } 2351 } 2352 return stack.back(); 2353 } 2354 2355 bool DWARFExpression::ParseDWARFLocationList( 2356 const DWARFUnit *dwarf_cu, const DataExtractor &data, 2357 DWARFExpressionList *location_list) { 2358 location_list->Clear(); 2359 std::unique_ptr<llvm::DWARFLocationTable> loctable_up = 2360 dwarf_cu->GetLocationTable(data); 2361 Log *log = GetLog(LLDBLog::Expressions); 2362 auto lookup_addr = 2363 [&](uint32_t index) -> std::optional<llvm::object::SectionedAddress> { 2364 addr_t address = dwarf_cu->ReadAddressFromDebugAddrSection(index); 2365 if (address == LLDB_INVALID_ADDRESS) 2366 return std::nullopt; 2367 return llvm::object::SectionedAddress{address}; 2368 }; 2369 auto process_list = [&](llvm::Expected<llvm::DWARFLocationExpression> loc) { 2370 if (!loc) { 2371 LLDB_LOG_ERROR(log, loc.takeError(), "{0}"); 2372 return true; 2373 } 2374 auto buffer_sp = 2375 std::make_shared<DataBufferHeap>(loc->Expr.data(), loc->Expr.size()); 2376 DWARFExpression expr = DWARFExpression(DataExtractor( 2377 buffer_sp, data.GetByteOrder(), data.GetAddressByteSize())); 2378 location_list->AddExpression(loc->Range->LowPC, loc->Range->HighPC, expr); 2379 return true; 2380 }; 2381 llvm::Error error = loctable_up->visitAbsoluteLocationList( 2382 0, llvm::object::SectionedAddress{dwarf_cu->GetBaseAddress()}, 2383 lookup_addr, process_list); 2384 location_list->Sort(); 2385 if (error) { 2386 LLDB_LOG_ERROR(log, std::move(error), "{0}"); 2387 return false; 2388 } 2389 return true; 2390 } 2391 2392 bool DWARFExpression::MatchesOperand( 2393 StackFrame &frame, const Instruction::Operand &operand) const { 2394 using namespace OperandMatchers; 2395 2396 RegisterContextSP reg_ctx_sp = frame.GetRegisterContext(); 2397 if (!reg_ctx_sp) { 2398 return false; 2399 } 2400 2401 DataExtractor opcodes(m_data); 2402 2403 lldb::offset_t op_offset = 0; 2404 uint8_t opcode = opcodes.GetU8(&op_offset); 2405 2406 if (opcode == DW_OP_fbreg) { 2407 int64_t offset = opcodes.GetSLEB128(&op_offset); 2408 2409 DWARFExpressionList *fb_expr = frame.GetFrameBaseExpression(nullptr); 2410 if (!fb_expr) { 2411 return false; 2412 } 2413 2414 auto recurse = [&frame, fb_expr](const Instruction::Operand &child) { 2415 return fb_expr->MatchesOperand(frame, child); 2416 }; 2417 2418 if (!offset && 2419 MatchUnaryOp(MatchOpType(Instruction::Operand::Type::Dereference), 2420 recurse)(operand)) { 2421 return true; 2422 } 2423 2424 return MatchUnaryOp( 2425 MatchOpType(Instruction::Operand::Type::Dereference), 2426 MatchBinaryOp(MatchOpType(Instruction::Operand::Type::Sum), 2427 MatchImmOp(offset), recurse))(operand); 2428 } 2429 2430 bool dereference = false; 2431 const RegisterInfo *reg = nullptr; 2432 int64_t offset = 0; 2433 2434 if (opcode >= DW_OP_reg0 && opcode <= DW_OP_reg31) { 2435 reg = reg_ctx_sp->GetRegisterInfo(m_reg_kind, opcode - DW_OP_reg0); 2436 } else if (opcode >= DW_OP_breg0 && opcode <= DW_OP_breg31) { 2437 offset = opcodes.GetSLEB128(&op_offset); 2438 reg = reg_ctx_sp->GetRegisterInfo(m_reg_kind, opcode - DW_OP_breg0); 2439 } else if (opcode == DW_OP_regx) { 2440 uint32_t reg_num = static_cast<uint32_t>(opcodes.GetULEB128(&op_offset)); 2441 reg = reg_ctx_sp->GetRegisterInfo(m_reg_kind, reg_num); 2442 } else if (opcode == DW_OP_bregx) { 2443 uint32_t reg_num = static_cast<uint32_t>(opcodes.GetULEB128(&op_offset)); 2444 offset = opcodes.GetSLEB128(&op_offset); 2445 reg = reg_ctx_sp->GetRegisterInfo(m_reg_kind, reg_num); 2446 } else { 2447 return false; 2448 } 2449 2450 if (!reg) { 2451 return false; 2452 } 2453 2454 if (dereference) { 2455 if (!offset && 2456 MatchUnaryOp(MatchOpType(Instruction::Operand::Type::Dereference), 2457 MatchRegOp(*reg))(operand)) { 2458 return true; 2459 } 2460 2461 return MatchUnaryOp( 2462 MatchOpType(Instruction::Operand::Type::Dereference), 2463 MatchBinaryOp(MatchOpType(Instruction::Operand::Type::Sum), 2464 MatchRegOp(*reg), 2465 MatchImmOp(offset)))(operand); 2466 } else { 2467 return MatchRegOp(*reg)(operand); 2468 } 2469 } 2470