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 49 // DWARFExpression constructor 50 DWARFExpression::DWARFExpression() : m_data() {} 51 52 DWARFExpression::DWARFExpression(const DataExtractor &data) : m_data(data) {} 53 54 // Destructor 55 DWARFExpression::~DWARFExpression() = default; 56 57 bool DWARFExpression::IsValid() const { return m_data.GetByteSize() > 0; } 58 59 void DWARFExpression::UpdateValue(uint64_t const_value, 60 lldb::offset_t const_value_byte_size, 61 uint8_t addr_byte_size) { 62 if (!const_value_byte_size) 63 return; 64 65 m_data.SetData( 66 DataBufferSP(new DataBufferHeap(&const_value, const_value_byte_size))); 67 m_data.SetByteOrder(endian::InlHostByteOrder()); 68 m_data.SetAddressByteSize(addr_byte_size); 69 } 70 71 void DWARFExpression::DumpLocation(Stream *s, lldb::DescriptionLevel level, 72 ABI *abi) const { 73 auto *MCRegInfo = abi ? &abi->GetMCRegisterInfo() : nullptr; 74 auto GetRegName = [&MCRegInfo](uint64_t DwarfRegNum, 75 bool IsEH) -> llvm::StringRef { 76 if (!MCRegInfo) 77 return {}; 78 if (std::optional<unsigned> LLVMRegNum = 79 MCRegInfo->getLLVMRegNum(DwarfRegNum, IsEH)) 80 if (const char *RegName = MCRegInfo->getName(*LLVMRegNum)) 81 return llvm::StringRef(RegName); 82 return {}; 83 }; 84 llvm::DIDumpOptions DumpOpts; 85 DumpOpts.GetNameForDWARFReg = GetRegName; 86 llvm::DWARFExpression(m_data.GetAsLLVM(), m_data.GetAddressByteSize()) 87 .print(s->AsRawOstream(), DumpOpts, nullptr); 88 } 89 90 RegisterKind DWARFExpression::GetRegisterKind() const { return m_reg_kind; } 91 92 void DWARFExpression::SetRegisterKind(RegisterKind reg_kind) { 93 m_reg_kind = reg_kind; 94 } 95 96 97 static bool ReadRegisterValueAsScalar(RegisterContext *reg_ctx, 98 lldb::RegisterKind reg_kind, 99 uint32_t reg_num, Status *error_ptr, 100 Value &value) { 101 if (reg_ctx == nullptr) { 102 if (error_ptr) 103 error_ptr->SetErrorString("No register context in frame.\n"); 104 } else { 105 uint32_t native_reg = 106 reg_ctx->ConvertRegisterKindToRegisterNumber(reg_kind, reg_num); 107 if (native_reg == LLDB_INVALID_REGNUM) { 108 if (error_ptr) 109 error_ptr->SetErrorStringWithFormat("Unable to convert register " 110 "kind=%u reg_num=%u to a native " 111 "register number.\n", 112 reg_kind, reg_num); 113 } else { 114 const RegisterInfo *reg_info = 115 reg_ctx->GetRegisterInfoAtIndex(native_reg); 116 RegisterValue reg_value; 117 if (reg_ctx->ReadRegister(reg_info, reg_value)) { 118 if (reg_value.GetScalarValue(value.GetScalar())) { 119 value.SetValueType(Value::ValueType::Scalar); 120 value.SetContext(Value::ContextType::RegisterInfo, 121 const_cast<RegisterInfo *>(reg_info)); 122 if (error_ptr) 123 error_ptr->Clear(); 124 return true; 125 } else { 126 // If we get this error, then we need to implement a value buffer in 127 // the dwarf expression evaluation function... 128 if (error_ptr) 129 error_ptr->SetErrorStringWithFormat( 130 "register %s can't be converted to a scalar value", 131 reg_info->name); 132 } 133 } else { 134 if (error_ptr) 135 error_ptr->SetErrorStringWithFormat("register %s is not available", 136 reg_info->name); 137 } 138 } 139 } 140 return false; 141 } 142 143 /// Return the length in bytes of the set of operands for \p op. No guarantees 144 /// are made on the state of \p data after this call. 145 static offset_t GetOpcodeDataSize(const DataExtractor &data, 146 const lldb::offset_t data_offset, 147 const uint8_t op, const DWARFUnit *dwarf_cu) { 148 lldb::offset_t offset = data_offset; 149 switch (op) { 150 case DW_OP_addr: 151 case DW_OP_call_ref: // 0x9a 1 address sized offset of DIE (DWARF3) 152 return data.GetAddressByteSize(); 153 154 // Opcodes with no arguments 155 case DW_OP_deref: // 0x06 156 case DW_OP_dup: // 0x12 157 case DW_OP_drop: // 0x13 158 case DW_OP_over: // 0x14 159 case DW_OP_swap: // 0x16 160 case DW_OP_rot: // 0x17 161 case DW_OP_xderef: // 0x18 162 case DW_OP_abs: // 0x19 163 case DW_OP_and: // 0x1a 164 case DW_OP_div: // 0x1b 165 case DW_OP_minus: // 0x1c 166 case DW_OP_mod: // 0x1d 167 case DW_OP_mul: // 0x1e 168 case DW_OP_neg: // 0x1f 169 case DW_OP_not: // 0x20 170 case DW_OP_or: // 0x21 171 case DW_OP_plus: // 0x22 172 case DW_OP_shl: // 0x24 173 case DW_OP_shr: // 0x25 174 case DW_OP_shra: // 0x26 175 case DW_OP_xor: // 0x27 176 case DW_OP_eq: // 0x29 177 case DW_OP_ge: // 0x2a 178 case DW_OP_gt: // 0x2b 179 case DW_OP_le: // 0x2c 180 case DW_OP_lt: // 0x2d 181 case DW_OP_ne: // 0x2e 182 case DW_OP_lit0: // 0x30 183 case DW_OP_lit1: // 0x31 184 case DW_OP_lit2: // 0x32 185 case DW_OP_lit3: // 0x33 186 case DW_OP_lit4: // 0x34 187 case DW_OP_lit5: // 0x35 188 case DW_OP_lit6: // 0x36 189 case DW_OP_lit7: // 0x37 190 case DW_OP_lit8: // 0x38 191 case DW_OP_lit9: // 0x39 192 case DW_OP_lit10: // 0x3A 193 case DW_OP_lit11: // 0x3B 194 case DW_OP_lit12: // 0x3C 195 case DW_OP_lit13: // 0x3D 196 case DW_OP_lit14: // 0x3E 197 case DW_OP_lit15: // 0x3F 198 case DW_OP_lit16: // 0x40 199 case DW_OP_lit17: // 0x41 200 case DW_OP_lit18: // 0x42 201 case DW_OP_lit19: // 0x43 202 case DW_OP_lit20: // 0x44 203 case DW_OP_lit21: // 0x45 204 case DW_OP_lit22: // 0x46 205 case DW_OP_lit23: // 0x47 206 case DW_OP_lit24: // 0x48 207 case DW_OP_lit25: // 0x49 208 case DW_OP_lit26: // 0x4A 209 case DW_OP_lit27: // 0x4B 210 case DW_OP_lit28: // 0x4C 211 case DW_OP_lit29: // 0x4D 212 case DW_OP_lit30: // 0x4E 213 case DW_OP_lit31: // 0x4f 214 case DW_OP_reg0: // 0x50 215 case DW_OP_reg1: // 0x51 216 case DW_OP_reg2: // 0x52 217 case DW_OP_reg3: // 0x53 218 case DW_OP_reg4: // 0x54 219 case DW_OP_reg5: // 0x55 220 case DW_OP_reg6: // 0x56 221 case DW_OP_reg7: // 0x57 222 case DW_OP_reg8: // 0x58 223 case DW_OP_reg9: // 0x59 224 case DW_OP_reg10: // 0x5A 225 case DW_OP_reg11: // 0x5B 226 case DW_OP_reg12: // 0x5C 227 case DW_OP_reg13: // 0x5D 228 case DW_OP_reg14: // 0x5E 229 case DW_OP_reg15: // 0x5F 230 case DW_OP_reg16: // 0x60 231 case DW_OP_reg17: // 0x61 232 case DW_OP_reg18: // 0x62 233 case DW_OP_reg19: // 0x63 234 case DW_OP_reg20: // 0x64 235 case DW_OP_reg21: // 0x65 236 case DW_OP_reg22: // 0x66 237 case DW_OP_reg23: // 0x67 238 case DW_OP_reg24: // 0x68 239 case DW_OP_reg25: // 0x69 240 case DW_OP_reg26: // 0x6A 241 case DW_OP_reg27: // 0x6B 242 case DW_OP_reg28: // 0x6C 243 case DW_OP_reg29: // 0x6D 244 case DW_OP_reg30: // 0x6E 245 case DW_OP_reg31: // 0x6F 246 case DW_OP_nop: // 0x96 247 case DW_OP_push_object_address: // 0x97 DWARF3 248 case DW_OP_form_tls_address: // 0x9b DWARF3 249 case DW_OP_call_frame_cfa: // 0x9c DWARF3 250 case DW_OP_stack_value: // 0x9f DWARF4 251 case DW_OP_GNU_push_tls_address: // 0xe0 GNU extension 252 return 0; 253 254 // Opcodes with a single 1 byte arguments 255 case DW_OP_const1u: // 0x08 1 1-byte constant 256 case DW_OP_const1s: // 0x09 1 1-byte constant 257 case DW_OP_pick: // 0x15 1 1-byte stack index 258 case DW_OP_deref_size: // 0x94 1 1-byte size of data retrieved 259 case DW_OP_xderef_size: // 0x95 1 1-byte size of data retrieved 260 return 1; 261 262 // Opcodes with a single 2 byte arguments 263 case DW_OP_const2u: // 0x0a 1 2-byte constant 264 case DW_OP_const2s: // 0x0b 1 2-byte constant 265 case DW_OP_skip: // 0x2f 1 signed 2-byte constant 266 case DW_OP_bra: // 0x28 1 signed 2-byte constant 267 case DW_OP_call2: // 0x98 1 2-byte offset of DIE (DWARF3) 268 return 2; 269 270 // Opcodes with a single 4 byte arguments 271 case DW_OP_const4u: // 0x0c 1 4-byte constant 272 case DW_OP_const4s: // 0x0d 1 4-byte constant 273 case DW_OP_call4: // 0x99 1 4-byte offset of DIE (DWARF3) 274 return 4; 275 276 // Opcodes with a single 8 byte arguments 277 case DW_OP_const8u: // 0x0e 1 8-byte constant 278 case DW_OP_const8s: // 0x0f 1 8-byte constant 279 return 8; 280 281 // All opcodes that have a single ULEB (signed or unsigned) argument 282 case DW_OP_addrx: // 0xa1 1 ULEB128 index 283 case DW_OP_constu: // 0x10 1 ULEB128 constant 284 case DW_OP_consts: // 0x11 1 SLEB128 constant 285 case DW_OP_plus_uconst: // 0x23 1 ULEB128 addend 286 case DW_OP_breg0: // 0x70 1 ULEB128 register 287 case DW_OP_breg1: // 0x71 1 ULEB128 register 288 case DW_OP_breg2: // 0x72 1 ULEB128 register 289 case DW_OP_breg3: // 0x73 1 ULEB128 register 290 case DW_OP_breg4: // 0x74 1 ULEB128 register 291 case DW_OP_breg5: // 0x75 1 ULEB128 register 292 case DW_OP_breg6: // 0x76 1 ULEB128 register 293 case DW_OP_breg7: // 0x77 1 ULEB128 register 294 case DW_OP_breg8: // 0x78 1 ULEB128 register 295 case DW_OP_breg9: // 0x79 1 ULEB128 register 296 case DW_OP_breg10: // 0x7a 1 ULEB128 register 297 case DW_OP_breg11: // 0x7b 1 ULEB128 register 298 case DW_OP_breg12: // 0x7c 1 ULEB128 register 299 case DW_OP_breg13: // 0x7d 1 ULEB128 register 300 case DW_OP_breg14: // 0x7e 1 ULEB128 register 301 case DW_OP_breg15: // 0x7f 1 ULEB128 register 302 case DW_OP_breg16: // 0x80 1 ULEB128 register 303 case DW_OP_breg17: // 0x81 1 ULEB128 register 304 case DW_OP_breg18: // 0x82 1 ULEB128 register 305 case DW_OP_breg19: // 0x83 1 ULEB128 register 306 case DW_OP_breg20: // 0x84 1 ULEB128 register 307 case DW_OP_breg21: // 0x85 1 ULEB128 register 308 case DW_OP_breg22: // 0x86 1 ULEB128 register 309 case DW_OP_breg23: // 0x87 1 ULEB128 register 310 case DW_OP_breg24: // 0x88 1 ULEB128 register 311 case DW_OP_breg25: // 0x89 1 ULEB128 register 312 case DW_OP_breg26: // 0x8a 1 ULEB128 register 313 case DW_OP_breg27: // 0x8b 1 ULEB128 register 314 case DW_OP_breg28: // 0x8c 1 ULEB128 register 315 case DW_OP_breg29: // 0x8d 1 ULEB128 register 316 case DW_OP_breg30: // 0x8e 1 ULEB128 register 317 case DW_OP_breg31: // 0x8f 1 ULEB128 register 318 case DW_OP_regx: // 0x90 1 ULEB128 register 319 case DW_OP_fbreg: // 0x91 1 SLEB128 offset 320 case DW_OP_piece: // 0x93 1 ULEB128 size of piece addressed 321 case DW_OP_GNU_addr_index: // 0xfb 1 ULEB128 index 322 case DW_OP_GNU_const_index: // 0xfc 1 ULEB128 index 323 data.Skip_LEB128(&offset); 324 return offset - data_offset; 325 326 // All opcodes that have a 2 ULEB (signed or unsigned) arguments 327 case DW_OP_bregx: // 0x92 2 ULEB128 register followed by SLEB128 offset 328 case DW_OP_bit_piece: // 0x9d ULEB128 bit size, ULEB128 bit offset (DWARF3); 329 data.Skip_LEB128(&offset); 330 data.Skip_LEB128(&offset); 331 return offset - data_offset; 332 333 case DW_OP_implicit_value: // 0x9e ULEB128 size followed by block of that size 334 // (DWARF4) 335 { 336 uint64_t block_len = data.Skip_LEB128(&offset); 337 offset += block_len; 338 return offset - data_offset; 339 } 340 341 case DW_OP_GNU_entry_value: 342 case DW_OP_entry_value: // 0xa3 ULEB128 size + variable-length block 343 { 344 uint64_t subexpr_len = data.GetULEB128(&offset); 345 return (offset - data_offset) + subexpr_len; 346 } 347 348 default: 349 if (!dwarf_cu) { 350 return LLDB_INVALID_OFFSET; 351 } 352 return dwarf_cu->GetSymbolFileDWARF().GetVendorDWARFOpcodeSize( 353 data, data_offset, op); 354 } 355 } 356 357 lldb::addr_t DWARFExpression::GetLocation_DW_OP_addr(const DWARFUnit *dwarf_cu, 358 bool &error) const { 359 error = false; 360 lldb::offset_t offset = 0; 361 while (m_data.ValidOffset(offset)) { 362 const uint8_t op = m_data.GetU8(&offset); 363 364 if (op == DW_OP_addr) 365 return m_data.GetAddress(&offset); 366 if (op == DW_OP_GNU_addr_index || op == DW_OP_addrx) { 367 uint64_t index = m_data.GetULEB128(&offset); 368 if (dwarf_cu) 369 return dwarf_cu->ReadAddressFromDebugAddrSection(index); 370 error = true; 371 break; 372 } 373 const offset_t op_arg_size = 374 GetOpcodeDataSize(m_data, offset, op, dwarf_cu); 375 if (op_arg_size == LLDB_INVALID_OFFSET) { 376 error = true; 377 break; 378 } 379 offset += op_arg_size; 380 } 381 return LLDB_INVALID_ADDRESS; 382 } 383 384 bool DWARFExpression::Update_DW_OP_addr(const DWARFUnit *dwarf_cu, 385 lldb::addr_t file_addr) { 386 lldb::offset_t offset = 0; 387 while (m_data.ValidOffset(offset)) { 388 const uint8_t op = m_data.GetU8(&offset); 389 390 if (op == DW_OP_addr) { 391 const uint32_t addr_byte_size = m_data.GetAddressByteSize(); 392 // We have to make a copy of the data as we don't know if this data is 393 // from a read only memory mapped buffer, so we duplicate all of the data 394 // first, then modify it, and if all goes well, we then replace the data 395 // for this expression 396 397 // Make en encoder that contains a copy of the location expression data 398 // so we can write the address into the buffer using the correct byte 399 // order. 400 DataEncoder encoder(m_data.GetDataStart(), m_data.GetByteSize(), 401 m_data.GetByteOrder(), addr_byte_size); 402 403 // Replace the address in the new buffer 404 if (encoder.PutAddress(offset, file_addr) == UINT32_MAX) 405 return false; 406 407 // All went well, so now we can reset the data using a shared pointer to 408 // the heap data so "m_data" will now correctly manage the heap data. 409 m_data.SetData(encoder.GetDataBuffer()); 410 return true; 411 } 412 if (op == DW_OP_addrx) { 413 // Replace DW_OP_addrx with DW_OP_addr, since we can't modify the 414 // read-only debug_addr table. 415 // Subtract one to account for the opcode. 416 llvm::ArrayRef data_before_op = m_data.GetData().take_front(offset - 1); 417 418 // Read the addrx index to determine how many bytes it needs. 419 const lldb::offset_t old_offset = offset; 420 m_data.GetULEB128(&offset); 421 if (old_offset == offset) 422 return false; 423 llvm::ArrayRef data_after_op = m_data.GetData().drop_front(offset); 424 425 DataEncoder encoder(m_data.GetByteOrder(), m_data.GetAddressByteSize()); 426 encoder.AppendData(data_before_op); 427 encoder.AppendU8(DW_OP_addr); 428 encoder.AppendAddress(file_addr); 429 encoder.AppendData(data_after_op); 430 m_data.SetData(encoder.GetDataBuffer()); 431 return true; 432 } 433 const offset_t op_arg_size = 434 GetOpcodeDataSize(m_data, offset, op, dwarf_cu); 435 if (op_arg_size == LLDB_INVALID_OFFSET) 436 break; 437 offset += op_arg_size; 438 } 439 return false; 440 } 441 442 bool DWARFExpression::ContainsThreadLocalStorage( 443 const DWARFUnit *dwarf_cu) const { 444 lldb::offset_t offset = 0; 445 while (m_data.ValidOffset(offset)) { 446 const uint8_t op = m_data.GetU8(&offset); 447 448 if (op == DW_OP_form_tls_address || op == DW_OP_GNU_push_tls_address) 449 return true; 450 const offset_t op_arg_size = 451 GetOpcodeDataSize(m_data, offset, op, dwarf_cu); 452 if (op_arg_size == LLDB_INVALID_OFFSET) 453 return false; 454 offset += op_arg_size; 455 } 456 return false; 457 } 458 bool DWARFExpression::LinkThreadLocalStorage( 459 const DWARFUnit *dwarf_cu, 460 std::function<lldb::addr_t(lldb::addr_t file_addr)> const 461 &link_address_callback) { 462 const uint32_t addr_byte_size = m_data.GetAddressByteSize(); 463 // We have to make a copy of the data as we don't know if this data is from a 464 // read only memory mapped buffer, so we duplicate all of the data first, 465 // then modify it, and if all goes well, we then replace the data for this 466 // expression. 467 // Make en encoder that contains a copy of the location expression data so we 468 // can write the address into the buffer using the correct byte order. 469 DataEncoder encoder(m_data.GetDataStart(), m_data.GetByteSize(), 470 m_data.GetByteOrder(), addr_byte_size); 471 472 lldb::offset_t offset = 0; 473 lldb::offset_t const_offset = 0; 474 lldb::addr_t const_value = 0; 475 size_t const_byte_size = 0; 476 while (m_data.ValidOffset(offset)) { 477 const uint8_t op = m_data.GetU8(&offset); 478 479 bool decoded_data = false; 480 switch (op) { 481 case DW_OP_const4u: 482 // Remember the const offset in case we later have a 483 // DW_OP_form_tls_address or DW_OP_GNU_push_tls_address 484 const_offset = offset; 485 const_value = m_data.GetU32(&offset); 486 decoded_data = true; 487 const_byte_size = 4; 488 break; 489 490 case DW_OP_const8u: 491 // Remember the const offset in case we later have a 492 // DW_OP_form_tls_address or DW_OP_GNU_push_tls_address 493 const_offset = offset; 494 const_value = m_data.GetU64(&offset); 495 decoded_data = true; 496 const_byte_size = 8; 497 break; 498 499 case DW_OP_form_tls_address: 500 case DW_OP_GNU_push_tls_address: 501 // DW_OP_form_tls_address and DW_OP_GNU_push_tls_address must be preceded 502 // by a file address on the stack. We assume that DW_OP_const4u or 503 // DW_OP_const8u is used for these values, and we check that the last 504 // opcode we got before either of these was DW_OP_const4u or 505 // DW_OP_const8u. If so, then we can link the value accordingly. For 506 // Darwin, the value in the DW_OP_const4u or DW_OP_const8u is the file 507 // address of a structure that contains a function pointer, the pthread 508 // key and the offset into the data pointed to by the pthread key. So we 509 // must link this address and also set the module of this expression to 510 // the new_module_sp so we can resolve the file address correctly 511 if (const_byte_size > 0) { 512 lldb::addr_t linked_file_addr = link_address_callback(const_value); 513 if (linked_file_addr == LLDB_INVALID_ADDRESS) 514 return false; 515 // Replace the address in the new buffer 516 if (encoder.PutUnsigned(const_offset, const_byte_size, 517 linked_file_addr) == UINT32_MAX) 518 return false; 519 } 520 break; 521 522 default: 523 const_offset = 0; 524 const_value = 0; 525 const_byte_size = 0; 526 break; 527 } 528 529 if (!decoded_data) { 530 const offset_t op_arg_size = 531 GetOpcodeDataSize(m_data, offset, op, dwarf_cu); 532 if (op_arg_size == LLDB_INVALID_OFFSET) 533 return false; 534 else 535 offset += op_arg_size; 536 } 537 } 538 539 m_data.SetData(encoder.GetDataBuffer()); 540 return true; 541 } 542 543 static bool Evaluate_DW_OP_entry_value(std::vector<Value> &stack, 544 ExecutionContext *exe_ctx, 545 RegisterContext *reg_ctx, 546 const DataExtractor &opcodes, 547 lldb::offset_t &opcode_offset, 548 Status *error_ptr, Log *log) { 549 // DW_OP_entry_value(sub-expr) describes the location a variable had upon 550 // function entry: this variable location is presumed to be optimized out at 551 // the current PC value. The caller of the function may have call site 552 // information that describes an alternate location for the variable (e.g. a 553 // constant literal, or a spilled stack value) in the parent frame. 554 // 555 // Example (this is pseudo-code & pseudo-DWARF, but hopefully illustrative): 556 // 557 // void child(int &sink, int x) { 558 // ... 559 // /* "x" gets optimized out. */ 560 // 561 // /* The location of "x" here is: DW_OP_entry_value($reg2). */ 562 // ++sink; 563 // } 564 // 565 // void parent() { 566 // int sink; 567 // 568 // /* 569 // * The callsite information emitted here is: 570 // * 571 // * DW_TAG_call_site 572 // * DW_AT_return_pc ... (for "child(sink, 123);") 573 // * DW_TAG_call_site_parameter (for "sink") 574 // * DW_AT_location ($reg1) 575 // * DW_AT_call_value ($SP - 8) 576 // * DW_TAG_call_site_parameter (for "x") 577 // * DW_AT_location ($reg2) 578 // * DW_AT_call_value ($literal 123) 579 // * 580 // * DW_TAG_call_site 581 // * DW_AT_return_pc ... (for "child(sink, 456);") 582 // * ... 583 // */ 584 // child(sink, 123); 585 // child(sink, 456); 586 // } 587 // 588 // When the program stops at "++sink" within `child`, the debugger determines 589 // the call site by analyzing the return address. Once the call site is found, 590 // the debugger determines which parameter is referenced by DW_OP_entry_value 591 // and evaluates the corresponding location for that parameter in `parent`. 592 593 // 1. Find the function which pushed the current frame onto the stack. 594 if ((!exe_ctx || !exe_ctx->HasTargetScope()) || !reg_ctx) { 595 LLDB_LOG(log, "Evaluate_DW_OP_entry_value: no exe/reg context"); 596 return false; 597 } 598 599 StackFrame *current_frame = exe_ctx->GetFramePtr(); 600 Thread *thread = exe_ctx->GetThreadPtr(); 601 if (!current_frame || !thread) { 602 LLDB_LOG(log, "Evaluate_DW_OP_entry_value: no current frame/thread"); 603 return false; 604 } 605 606 Target &target = exe_ctx->GetTargetRef(); 607 StackFrameSP parent_frame = nullptr; 608 addr_t return_pc = LLDB_INVALID_ADDRESS; 609 uint32_t current_frame_idx = current_frame->GetFrameIndex(); 610 uint32_t num_frames = thread->GetStackFrameCount(); 611 for (uint32_t parent_frame_idx = current_frame_idx + 1; 612 parent_frame_idx < num_frames; ++parent_frame_idx) { 613 parent_frame = thread->GetStackFrameAtIndex(parent_frame_idx); 614 // Require a valid sequence of frames. 615 if (!parent_frame) 616 break; 617 618 // Record the first valid return address, even if this is an inlined frame, 619 // in order to look up the associated call edge in the first non-inlined 620 // parent frame. 621 if (return_pc == LLDB_INVALID_ADDRESS) { 622 return_pc = parent_frame->GetFrameCodeAddress().GetLoadAddress(&target); 623 LLDB_LOG(log, 624 "Evaluate_DW_OP_entry_value: immediate ancestor with pc = {0:x}", 625 return_pc); 626 } 627 628 // If we've found an inlined frame, skip it (these have no call site 629 // parameters). 630 if (parent_frame->IsInlined()) 631 continue; 632 633 // We've found the first non-inlined parent frame. 634 break; 635 } 636 if (!parent_frame || !parent_frame->GetRegisterContext()) { 637 LLDB_LOG(log, "Evaluate_DW_OP_entry_value: no parent frame with reg ctx"); 638 return false; 639 } 640 641 Function *parent_func = 642 parent_frame->GetSymbolContext(eSymbolContextFunction).function; 643 if (!parent_func) { 644 LLDB_LOG(log, "Evaluate_DW_OP_entry_value: no parent function"); 645 return false; 646 } 647 648 // 2. Find the call edge in the parent function responsible for creating the 649 // current activation. 650 Function *current_func = 651 current_frame->GetSymbolContext(eSymbolContextFunction).function; 652 if (!current_func) { 653 LLDB_LOG(log, "Evaluate_DW_OP_entry_value: no current function"); 654 return false; 655 } 656 657 CallEdge *call_edge = nullptr; 658 ModuleList &modlist = target.GetImages(); 659 ExecutionContext parent_exe_ctx = *exe_ctx; 660 parent_exe_ctx.SetFrameSP(parent_frame); 661 if (!parent_frame->IsArtificial()) { 662 // If the parent frame is not artificial, the current activation may be 663 // produced by an ambiguous tail call. In this case, refuse to proceed. 664 call_edge = parent_func->GetCallEdgeForReturnAddress(return_pc, target); 665 if (!call_edge) { 666 LLDB_LOG(log, 667 "Evaluate_DW_OP_entry_value: no call edge for retn-pc = {0:x} " 668 "in parent frame {1}", 669 return_pc, parent_func->GetName()); 670 return false; 671 } 672 Function *callee_func = call_edge->GetCallee(modlist, parent_exe_ctx); 673 if (callee_func != current_func) { 674 LLDB_LOG(log, "Evaluate_DW_OP_entry_value: ambiguous call sequence, " 675 "can't find real parent frame"); 676 return false; 677 } 678 } else { 679 // The StackFrameList solver machinery has deduced that an unambiguous tail 680 // call sequence that produced the current activation. The first edge in 681 // the parent that points to the current function must be valid. 682 for (auto &edge : parent_func->GetTailCallingEdges()) { 683 if (edge->GetCallee(modlist, parent_exe_ctx) == current_func) { 684 call_edge = edge.get(); 685 break; 686 } 687 } 688 } 689 if (!call_edge) { 690 LLDB_LOG(log, "Evaluate_DW_OP_entry_value: no unambiguous edge from parent " 691 "to current function"); 692 return false; 693 } 694 695 // 3. Attempt to locate the DW_OP_entry_value expression in the set of 696 // available call site parameters. If found, evaluate the corresponding 697 // parameter in the context of the parent frame. 698 const uint32_t subexpr_len = opcodes.GetULEB128(&opcode_offset); 699 const void *subexpr_data = opcodes.GetData(&opcode_offset, subexpr_len); 700 if (!subexpr_data) { 701 LLDB_LOG(log, "Evaluate_DW_OP_entry_value: subexpr could not be read"); 702 return false; 703 } 704 705 const CallSiteParameter *matched_param = nullptr; 706 for (const CallSiteParameter ¶m : call_edge->GetCallSiteParameters()) { 707 DataExtractor param_subexpr_extractor; 708 if (!param.LocationInCallee.GetExpressionData(param_subexpr_extractor)) 709 continue; 710 lldb::offset_t param_subexpr_offset = 0; 711 const void *param_subexpr_data = 712 param_subexpr_extractor.GetData(¶m_subexpr_offset, subexpr_len); 713 if (!param_subexpr_data || 714 param_subexpr_extractor.BytesLeft(param_subexpr_offset) != 0) 715 continue; 716 717 // At this point, the DW_OP_entry_value sub-expression and the callee-side 718 // expression in the call site parameter are known to have the same length. 719 // Check whether they are equal. 720 // 721 // Note that an equality check is sufficient: the contents of the 722 // DW_OP_entry_value subexpression are only used to identify the right call 723 // site parameter in the parent, and do not require any special handling. 724 if (memcmp(subexpr_data, param_subexpr_data, subexpr_len) == 0) { 725 matched_param = ¶m; 726 break; 727 } 728 } 729 if (!matched_param) { 730 LLDB_LOG(log, 731 "Evaluate_DW_OP_entry_value: no matching call site param found"); 732 return false; 733 } 734 735 // TODO: Add support for DW_OP_push_object_address within a DW_OP_entry_value 736 // subexpresion whenever llvm does. 737 Value result; 738 const DWARFExpressionList ¶m_expr = matched_param->LocationInCaller; 739 if (!param_expr.Evaluate(&parent_exe_ctx, 740 parent_frame->GetRegisterContext().get(), 741 LLDB_INVALID_ADDRESS, 742 /*initial_value_ptr=*/nullptr, 743 /*object_address_ptr=*/nullptr, result, error_ptr)) { 744 LLDB_LOG(log, 745 "Evaluate_DW_OP_entry_value: call site param evaluation failed"); 746 return false; 747 } 748 749 stack.push_back(result); 750 return true; 751 } 752 753 namespace { 754 /// The location description kinds described by the DWARF v5 755 /// specification. Composite locations are handled out-of-band and 756 /// thus aren't part of the enum. 757 enum LocationDescriptionKind { 758 Empty, 759 Memory, 760 Register, 761 Implicit 762 /* Composite*/ 763 }; 764 /// Adjust value's ValueType according to the kind of location description. 765 void UpdateValueTypeFromLocationDescription(Log *log, const DWARFUnit *dwarf_cu, 766 LocationDescriptionKind kind, 767 Value *value = nullptr) { 768 // Note that this function is conflating DWARF expressions with 769 // DWARF location descriptions. Perhaps it would be better to define 770 // a wrapper for DWARFExpression::Eval() that deals with DWARF 771 // location descriptions (which consist of one or more DWARF 772 // expressions). But doing this would mean we'd also need factor the 773 // handling of DW_OP_(bit_)piece out of this function. 774 if (dwarf_cu && dwarf_cu->GetVersion() >= 4) { 775 const char *log_msg = "DWARF location description kind: %s"; 776 switch (kind) { 777 case Empty: 778 LLDB_LOGF(log, log_msg, "Empty"); 779 break; 780 case Memory: 781 LLDB_LOGF(log, log_msg, "Memory"); 782 if (value->GetValueType() == Value::ValueType::Scalar) 783 value->SetValueType(Value::ValueType::LoadAddress); 784 break; 785 case Register: 786 LLDB_LOGF(log, log_msg, "Register"); 787 value->SetValueType(Value::ValueType::Scalar); 788 break; 789 case Implicit: 790 LLDB_LOGF(log, log_msg, "Implicit"); 791 if (value->GetValueType() == Value::ValueType::LoadAddress) 792 value->SetValueType(Value::ValueType::Scalar); 793 break; 794 } 795 } 796 } 797 } // namespace 798 799 /// Helper function to move common code used to resolve a file address and turn 800 /// into a load address. 801 /// 802 /// \param exe_ctx Pointer to the execution context 803 /// \param module_sp shared_ptr contains the module if we have one 804 /// \param error_ptr pointer to Status object if we have one 805 /// \param dw_op_type C-style string used to vary the error output 806 /// \param file_addr the file address we are trying to resolve and turn into a 807 /// load address 808 /// \param so_addr out parameter, will be set to load address or section offset 809 /// \param check_sectionoffset bool which determines if having a section offset 810 /// but not a load address is considerd a success 811 /// \returns std::optional containing the load address if resolving and getting 812 /// the load address succeed or an empty Optinal otherwise. If 813 /// check_sectionoffset is true we consider LLDB_INVALID_ADDRESS a 814 /// success if so_addr.IsSectionOffset() is true. 815 static std::optional<lldb::addr_t> 816 ResolveLoadAddress(ExecutionContext *exe_ctx, lldb::ModuleSP &module_sp, 817 Status *error_ptr, const char *dw_op_type, 818 lldb::addr_t file_addr, Address &so_addr, 819 bool check_sectionoffset = false) { 820 if (!module_sp) { 821 if (error_ptr) 822 error_ptr->SetErrorStringWithFormat( 823 "need module to resolve file address for %s", dw_op_type); 824 return {}; 825 } 826 827 if (!module_sp->ResolveFileAddress(file_addr, so_addr)) { 828 if (error_ptr) 829 error_ptr->SetErrorString("failed to resolve file address in module"); 830 return {}; 831 } 832 833 addr_t load_addr = so_addr.GetLoadAddress(exe_ctx->GetTargetPtr()); 834 835 if (load_addr == LLDB_INVALID_ADDRESS && 836 (check_sectionoffset && !so_addr.IsSectionOffset())) { 837 if (error_ptr) 838 error_ptr->SetErrorString("failed to resolve load address"); 839 return {}; 840 } 841 842 return load_addr; 843 } 844 845 /// Helper function to move common code used to load sized data from a uint8_t 846 /// buffer. 847 /// 848 /// \param addr_bytes uint8_t buffer containg raw data 849 /// \param size_addr_bytes how large is the underlying raw data 850 /// \param byte_order what is the byter order of the underlyig data 851 /// \param size How much of the underlying data we want to use 852 /// \return The underlying data converted into a Scalar 853 static Scalar DerefSizeExtractDataHelper(uint8_t *addr_bytes, 854 size_t size_addr_bytes, 855 ByteOrder byte_order, size_t size) { 856 DataExtractor addr_data(addr_bytes, size_addr_bytes, byte_order, size); 857 858 lldb::offset_t addr_data_offset = 0; 859 if (size <= 8) 860 return addr_data.GetMaxU64(&addr_data_offset, size); 861 else 862 return addr_data.GetAddress(&addr_data_offset); 863 } 864 865 bool DWARFExpression::Evaluate( 866 ExecutionContext *exe_ctx, RegisterContext *reg_ctx, 867 lldb::ModuleSP module_sp, const DataExtractor &opcodes, 868 const DWARFUnit *dwarf_cu, const lldb::RegisterKind reg_kind, 869 const Value *initial_value_ptr, const Value *object_address_ptr, 870 Value &result, Status *error_ptr) { 871 872 if (opcodes.GetByteSize() == 0) { 873 if (error_ptr) 874 error_ptr->SetErrorString( 875 "no location, value may have been optimized out"); 876 return false; 877 } 878 std::vector<Value> stack; 879 880 Process *process = nullptr; 881 StackFrame *frame = nullptr; 882 Target *target = nullptr; 883 884 if (exe_ctx) { 885 process = exe_ctx->GetProcessPtr(); 886 frame = exe_ctx->GetFramePtr(); 887 target = exe_ctx->GetTargetPtr(); 888 } 889 if (reg_ctx == nullptr && frame) 890 reg_ctx = frame->GetRegisterContext().get(); 891 892 if (initial_value_ptr) 893 stack.push_back(*initial_value_ptr); 894 895 lldb::offset_t offset = 0; 896 Value tmp; 897 uint32_t reg_num; 898 899 /// Insertion point for evaluating multi-piece expression. 900 uint64_t op_piece_offset = 0; 901 Value pieces; // Used for DW_OP_piece 902 903 Log *log = GetLog(LLDBLog::Expressions); 904 // A generic type is "an integral type that has the size of an address and an 905 // unspecified signedness". For now, just use the signedness of the operand. 906 // TODO: Implement a real typed stack, and store the genericness of the value 907 // there. 908 auto to_generic = [&](auto v) { 909 bool is_signed = std::is_signed<decltype(v)>::value; 910 return Scalar(llvm::APSInt( 911 llvm::APInt(8 * opcodes.GetAddressByteSize(), v, is_signed), 912 !is_signed)); 913 }; 914 915 // The default kind is a memory location. This is updated by any 916 // operation that changes this, such as DW_OP_stack_value, and reset 917 // by composition operations like DW_OP_piece. 918 LocationDescriptionKind dwarf4_location_description_kind = Memory; 919 920 while (opcodes.ValidOffset(offset)) { 921 const lldb::offset_t op_offset = offset; 922 const uint8_t op = opcodes.GetU8(&offset); 923 924 if (log && log->GetVerbose()) { 925 size_t count = stack.size(); 926 LLDB_LOGF(log, "Stack before operation has %" PRIu64 " values:", 927 (uint64_t)count); 928 for (size_t i = 0; i < count; ++i) { 929 StreamString new_value; 930 new_value.Printf("[%" PRIu64 "]", (uint64_t)i); 931 stack[i].Dump(&new_value); 932 LLDB_LOGF(log, " %s", new_value.GetData()); 933 } 934 LLDB_LOGF(log, "0x%8.8" PRIx64 ": %s", op_offset, 935 DW_OP_value_to_name(op)); 936 } 937 938 switch (op) { 939 // The DW_OP_addr operation has a single operand that encodes a machine 940 // address and whose size is the size of an address on the target machine. 941 case DW_OP_addr: 942 stack.push_back(Scalar(opcodes.GetAddress(&offset))); 943 if (target && 944 target->GetArchitecture().GetCore() == ArchSpec::eCore_wasm32) { 945 // wasm file sections aren't mapped into memory, therefore addresses can 946 // never point into a file section and are always LoadAddresses. 947 stack.back().SetValueType(Value::ValueType::LoadAddress); 948 } else { 949 stack.back().SetValueType(Value::ValueType::FileAddress); 950 } 951 break; 952 953 // The DW_OP_addr_sect_offset4 is used for any location expressions in 954 // shared libraries that have a location like: 955 // DW_OP_addr(0x1000) 956 // If this address resides in a shared library, then this virtual address 957 // won't make sense when it is evaluated in the context of a running 958 // process where shared libraries have been slid. To account for this, this 959 // new address type where we can store the section pointer and a 4 byte 960 // offset. 961 // case DW_OP_addr_sect_offset4: 962 // { 963 // result_type = eResultTypeFileAddress; 964 // lldb::Section *sect = (lldb::Section 965 // *)opcodes.GetMaxU64(&offset, sizeof(void *)); 966 // lldb::addr_t sect_offset = opcodes.GetU32(&offset); 967 // 968 // Address so_addr (sect, sect_offset); 969 // lldb::addr_t load_addr = so_addr.GetLoadAddress(); 970 // if (load_addr != LLDB_INVALID_ADDRESS) 971 // { 972 // // We successfully resolve a file address to a load 973 // // address. 974 // stack.push_back(load_addr); 975 // break; 976 // } 977 // else 978 // { 979 // // We were able 980 // if (error_ptr) 981 // error_ptr->SetErrorStringWithFormat ("Section %s in 982 // %s is not currently loaded.\n", 983 // sect->GetName().AsCString(), 984 // sect->GetModule()->GetFileSpec().GetFilename().AsCString()); 985 // return false; 986 // } 987 // } 988 // break; 989 990 // OPCODE: DW_OP_deref 991 // OPERANDS: none 992 // DESCRIPTION: Pops the top stack entry and treats it as an address. 993 // The value retrieved from that address is pushed. The size of the data 994 // retrieved from the dereferenced address is the size of an address on the 995 // target machine. 996 case DW_OP_deref: { 997 if (stack.empty()) { 998 if (error_ptr) 999 error_ptr->SetErrorString("Expression stack empty for DW_OP_deref."); 1000 return false; 1001 } 1002 Value::ValueType value_type = stack.back().GetValueType(); 1003 switch (value_type) { 1004 case Value::ValueType::HostAddress: { 1005 void *src = (void *)stack.back().GetScalar().ULongLong(); 1006 intptr_t ptr; 1007 ::memcpy(&ptr, src, sizeof(void *)); 1008 stack.back().GetScalar() = ptr; 1009 stack.back().ClearContext(); 1010 } break; 1011 case Value::ValueType::FileAddress: { 1012 auto file_addr = stack.back().GetScalar().ULongLong( 1013 LLDB_INVALID_ADDRESS); 1014 1015 Address so_addr; 1016 auto maybe_load_addr = ResolveLoadAddress( 1017 exe_ctx, module_sp, error_ptr, "DW_OP_deref", file_addr, so_addr); 1018 1019 if (!maybe_load_addr) 1020 return false; 1021 1022 stack.back().GetScalar() = *maybe_load_addr; 1023 // Fall through to load address promotion code below. 1024 } 1025 [[fallthrough]]; 1026 case Value::ValueType::Scalar: 1027 // Promote Scalar to LoadAddress and fall through. 1028 stack.back().SetValueType(Value::ValueType::LoadAddress); 1029 [[fallthrough]]; 1030 case Value::ValueType::LoadAddress: 1031 if (exe_ctx) { 1032 if (process) { 1033 lldb::addr_t pointer_addr = 1034 stack.back().GetScalar().ULongLong(LLDB_INVALID_ADDRESS); 1035 Status error; 1036 lldb::addr_t pointer_value = 1037 process->ReadPointerFromMemory(pointer_addr, error); 1038 if (pointer_value != LLDB_INVALID_ADDRESS) { 1039 if (ABISP abi_sp = process->GetABI()) 1040 pointer_value = abi_sp->FixCodeAddress(pointer_value); 1041 stack.back().GetScalar() = pointer_value; 1042 stack.back().ClearContext(); 1043 } else { 1044 if (error_ptr) 1045 error_ptr->SetErrorStringWithFormat( 1046 "Failed to dereference pointer from 0x%" PRIx64 1047 " for DW_OP_deref: %s\n", 1048 pointer_addr, error.AsCString()); 1049 return false; 1050 } 1051 } else { 1052 if (error_ptr) 1053 error_ptr->SetErrorString("NULL process for DW_OP_deref.\n"); 1054 return false; 1055 } 1056 } else { 1057 if (error_ptr) 1058 error_ptr->SetErrorString( 1059 "NULL execution context for DW_OP_deref.\n"); 1060 return false; 1061 } 1062 break; 1063 1064 case Value::ValueType::Invalid: 1065 if (error_ptr) 1066 error_ptr->SetErrorString("Invalid value type for DW_OP_deref.\n"); 1067 return false; 1068 } 1069 1070 } break; 1071 1072 // OPCODE: DW_OP_deref_size 1073 // OPERANDS: 1 1074 // 1 - uint8_t that specifies the size of the data to dereference. 1075 // DESCRIPTION: Behaves like the DW_OP_deref operation: it pops the top 1076 // stack entry and treats it as an address. The value retrieved from that 1077 // address is pushed. In the DW_OP_deref_size operation, however, the size 1078 // in bytes of the data retrieved from the dereferenced address is 1079 // specified by the single operand. This operand is a 1-byte unsigned 1080 // integral constant whose value may not be larger than the size of an 1081 // address on the target machine. The data retrieved is zero extended to 1082 // the size of an address on the target machine before being pushed on the 1083 // expression stack. 1084 case DW_OP_deref_size: { 1085 if (stack.empty()) { 1086 if (error_ptr) 1087 error_ptr->SetErrorString( 1088 "Expression stack empty for DW_OP_deref_size."); 1089 return false; 1090 } 1091 uint8_t size = opcodes.GetU8(&offset); 1092 if (size > 8) { 1093 if (error_ptr) 1094 error_ptr->SetErrorStringWithFormat( 1095 "Invalid address size for DW_OP_deref_size: %d\n", 1096 size); 1097 return false; 1098 } 1099 Value::ValueType value_type = stack.back().GetValueType(); 1100 switch (value_type) { 1101 case Value::ValueType::HostAddress: { 1102 void *src = (void *)stack.back().GetScalar().ULongLong(); 1103 intptr_t ptr; 1104 ::memcpy(&ptr, src, sizeof(void *)); 1105 // I can't decide whether the size operand should apply to the bytes in 1106 // their 1107 // lldb-host endianness or the target endianness.. I doubt this'll ever 1108 // come up but I'll opt for assuming big endian regardless. 1109 switch (size) { 1110 case 1: 1111 ptr = ptr & 0xff; 1112 break; 1113 case 2: 1114 ptr = ptr & 0xffff; 1115 break; 1116 case 3: 1117 ptr = ptr & 0xffffff; 1118 break; 1119 case 4: 1120 ptr = ptr & 0xffffffff; 1121 break; 1122 // the casts are added to work around the case where intptr_t is a 32 1123 // bit quantity; 1124 // presumably we won't hit the 5..7 cases if (void*) is 32-bits in this 1125 // program. 1126 case 5: 1127 ptr = (intptr_t)ptr & 0xffffffffffULL; 1128 break; 1129 case 6: 1130 ptr = (intptr_t)ptr & 0xffffffffffffULL; 1131 break; 1132 case 7: 1133 ptr = (intptr_t)ptr & 0xffffffffffffffULL; 1134 break; 1135 default: 1136 break; 1137 } 1138 stack.back().GetScalar() = ptr; 1139 stack.back().ClearContext(); 1140 } break; 1141 case Value::ValueType::FileAddress: { 1142 auto file_addr = 1143 stack.back().GetScalar().ULongLong(LLDB_INVALID_ADDRESS); 1144 Address so_addr; 1145 auto maybe_load_addr = 1146 ResolveLoadAddress(exe_ctx, module_sp, error_ptr, 1147 "DW_OP_deref_size", file_addr, so_addr, 1148 /*check_sectionoffset=*/true); 1149 1150 if (!maybe_load_addr) 1151 return false; 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 if (error_ptr) 1170 error_ptr->SetErrorStringWithFormat( 1171 "Failed to dereference pointer for DW_OP_deref_size: " 1172 "%s\n", 1173 error.AsCString()); 1174 return false; 1175 } 1176 } 1177 stack.back().GetScalar() = load_addr; 1178 // Fall through to load address promotion code below. 1179 } 1180 1181 [[fallthrough]]; 1182 case Value::ValueType::Scalar: 1183 case Value::ValueType::LoadAddress: 1184 if (exe_ctx) { 1185 if (process) { 1186 lldb::addr_t pointer_addr = 1187 stack.back().GetScalar().ULongLong(LLDB_INVALID_ADDRESS); 1188 uint8_t addr_bytes[sizeof(lldb::addr_t)]; 1189 Status error; 1190 if (process->ReadMemory(pointer_addr, &addr_bytes, size, error) == 1191 size) { 1192 1193 stack.back().GetScalar() = 1194 DerefSizeExtractDataHelper(addr_bytes, sizeof(addr_bytes), 1195 process->GetByteOrder(), size); 1196 stack.back().ClearContext(); 1197 } else { 1198 if (error_ptr) 1199 error_ptr->SetErrorStringWithFormat( 1200 "Failed to dereference pointer from 0x%" PRIx64 1201 " for DW_OP_deref: %s\n", 1202 pointer_addr, error.AsCString()); 1203 return false; 1204 } 1205 } else { 1206 if (error_ptr) 1207 error_ptr->SetErrorString("NULL process for DW_OP_deref_size.\n"); 1208 return false; 1209 } 1210 } else { 1211 if (error_ptr) 1212 error_ptr->SetErrorString( 1213 "NULL execution context for DW_OP_deref_size.\n"); 1214 return false; 1215 } 1216 break; 1217 1218 case Value::ValueType::Invalid: 1219 if (error_ptr) 1220 error_ptr->SetErrorString("Invalid value for DW_OP_deref_size.\n"); 1221 return false; 1222 } 1223 1224 } break; 1225 1226 // OPCODE: DW_OP_xderef_size 1227 // OPERANDS: 1 1228 // 1 - uint8_t that specifies the size of the data to dereference. 1229 // DESCRIPTION: Behaves like the DW_OP_xderef operation: the entry at 1230 // the top of the stack is treated as an address. The second stack entry is 1231 // treated as an "address space identifier" for those architectures that 1232 // support multiple address spaces. The top two stack elements are popped, 1233 // a data item is retrieved through an implementation-defined address 1234 // calculation and pushed as the new stack top. In the DW_OP_xderef_size 1235 // operation, however, the size in bytes of the data retrieved from the 1236 // dereferenced address is specified by the single operand. This operand is 1237 // a 1-byte unsigned integral constant whose value may not be larger than 1238 // the size of an address on the target machine. The data retrieved is zero 1239 // extended to the size of an address on the target machine before being 1240 // pushed on the expression stack. 1241 case DW_OP_xderef_size: 1242 if (error_ptr) 1243 error_ptr->SetErrorString("Unimplemented opcode: DW_OP_xderef_size."); 1244 return false; 1245 // OPCODE: DW_OP_xderef 1246 // OPERANDS: none 1247 // DESCRIPTION: Provides an extended dereference mechanism. The entry at 1248 // the top of the stack is treated as an address. The second stack entry is 1249 // treated as an "address space identifier" for those architectures that 1250 // support multiple address spaces. The top two stack elements are popped, 1251 // a data item is retrieved through an implementation-defined address 1252 // calculation and pushed as the new stack top. The size of the data 1253 // retrieved from the dereferenced address is the size of an address on the 1254 // target machine. 1255 case DW_OP_xderef: 1256 if (error_ptr) 1257 error_ptr->SetErrorString("Unimplemented opcode: DW_OP_xderef."); 1258 return false; 1259 1260 // All DW_OP_constXXX opcodes have a single operand as noted below: 1261 // 1262 // Opcode Operand 1 1263 // DW_OP_const1u 1-byte unsigned integer constant 1264 // DW_OP_const1s 1-byte signed integer constant 1265 // DW_OP_const2u 2-byte unsigned integer constant 1266 // DW_OP_const2s 2-byte signed integer constant 1267 // DW_OP_const4u 4-byte unsigned integer constant 1268 // DW_OP_const4s 4-byte signed integer constant 1269 // DW_OP_const8u 8-byte unsigned integer constant 1270 // DW_OP_const8s 8-byte signed integer constant 1271 // DW_OP_constu unsigned LEB128 integer constant 1272 // DW_OP_consts signed LEB128 integer constant 1273 case DW_OP_const1u: 1274 stack.push_back(to_generic(opcodes.GetU8(&offset))); 1275 break; 1276 case DW_OP_const1s: 1277 stack.push_back(to_generic((int8_t)opcodes.GetU8(&offset))); 1278 break; 1279 case DW_OP_const2u: 1280 stack.push_back(to_generic(opcodes.GetU16(&offset))); 1281 break; 1282 case DW_OP_const2s: 1283 stack.push_back(to_generic((int16_t)opcodes.GetU16(&offset))); 1284 break; 1285 case DW_OP_const4u: 1286 stack.push_back(to_generic(opcodes.GetU32(&offset))); 1287 break; 1288 case DW_OP_const4s: 1289 stack.push_back(to_generic((int32_t)opcodes.GetU32(&offset))); 1290 break; 1291 case DW_OP_const8u: 1292 stack.push_back(to_generic(opcodes.GetU64(&offset))); 1293 break; 1294 case DW_OP_const8s: 1295 stack.push_back(to_generic((int64_t)opcodes.GetU64(&offset))); 1296 break; 1297 // These should also use to_generic, but we can't do that due to a 1298 // producer-side bug in llvm. See llvm.org/pr48087. 1299 case DW_OP_constu: 1300 stack.push_back(Scalar(opcodes.GetULEB128(&offset))); 1301 break; 1302 case DW_OP_consts: 1303 stack.push_back(Scalar(opcodes.GetSLEB128(&offset))); 1304 break; 1305 1306 // OPCODE: DW_OP_dup 1307 // OPERANDS: none 1308 // DESCRIPTION: duplicates the value at the top of the stack 1309 case DW_OP_dup: 1310 if (stack.empty()) { 1311 if (error_ptr) 1312 error_ptr->SetErrorString("Expression stack empty for DW_OP_dup."); 1313 return false; 1314 } else 1315 stack.push_back(stack.back()); 1316 break; 1317 1318 // OPCODE: DW_OP_drop 1319 // OPERANDS: none 1320 // DESCRIPTION: pops the value at the top of the stack 1321 case DW_OP_drop: 1322 if (stack.empty()) { 1323 if (error_ptr) 1324 error_ptr->SetErrorString("Expression stack empty for DW_OP_drop."); 1325 return false; 1326 } else 1327 stack.pop_back(); 1328 break; 1329 1330 // OPCODE: DW_OP_over 1331 // OPERANDS: none 1332 // DESCRIPTION: Duplicates the entry currently second in the stack at 1333 // the top of the stack. 1334 case DW_OP_over: 1335 if (stack.size() < 2) { 1336 if (error_ptr) 1337 error_ptr->SetErrorString( 1338 "Expression stack needs at least 2 items for DW_OP_over."); 1339 return false; 1340 } else 1341 stack.push_back(stack[stack.size() - 2]); 1342 break; 1343 1344 // OPCODE: DW_OP_pick 1345 // OPERANDS: uint8_t index into the current stack 1346 // DESCRIPTION: The stack entry with the specified index (0 through 255, 1347 // inclusive) is pushed on the stack 1348 case DW_OP_pick: { 1349 uint8_t pick_idx = opcodes.GetU8(&offset); 1350 if (pick_idx < stack.size()) 1351 stack.push_back(stack[stack.size() - 1 - pick_idx]); 1352 else { 1353 if (error_ptr) 1354 error_ptr->SetErrorStringWithFormat( 1355 "Index %u out of range for DW_OP_pick.\n", pick_idx); 1356 return false; 1357 } 1358 } break; 1359 1360 // OPCODE: DW_OP_swap 1361 // OPERANDS: none 1362 // DESCRIPTION: swaps the top two stack entries. The entry at the top 1363 // of the stack becomes the second stack entry, and the second entry 1364 // becomes the top of the stack 1365 case DW_OP_swap: 1366 if (stack.size() < 2) { 1367 if (error_ptr) 1368 error_ptr->SetErrorString( 1369 "Expression stack needs at least 2 items for DW_OP_swap."); 1370 return false; 1371 } else { 1372 tmp = stack.back(); 1373 stack.back() = stack[stack.size() - 2]; 1374 stack[stack.size() - 2] = tmp; 1375 } 1376 break; 1377 1378 // OPCODE: DW_OP_rot 1379 // OPERANDS: none 1380 // DESCRIPTION: Rotates the first three stack entries. The entry at 1381 // the top of the stack becomes the third stack entry, the second entry 1382 // becomes the top of the stack, and the third entry becomes the second 1383 // entry. 1384 case DW_OP_rot: 1385 if (stack.size() < 3) { 1386 if (error_ptr) 1387 error_ptr->SetErrorString( 1388 "Expression stack needs at least 3 items for DW_OP_rot."); 1389 return false; 1390 } else { 1391 size_t last_idx = stack.size() - 1; 1392 Value old_top = stack[last_idx]; 1393 stack[last_idx] = stack[last_idx - 1]; 1394 stack[last_idx - 1] = stack[last_idx - 2]; 1395 stack[last_idx - 2] = old_top; 1396 } 1397 break; 1398 1399 // OPCODE: DW_OP_abs 1400 // OPERANDS: none 1401 // DESCRIPTION: pops the top stack entry, interprets it as a signed 1402 // value and pushes its absolute value. If the absolute value can not be 1403 // represented, the result is undefined. 1404 case DW_OP_abs: 1405 if (stack.empty()) { 1406 if (error_ptr) 1407 error_ptr->SetErrorString( 1408 "Expression stack needs at least 1 item for DW_OP_abs."); 1409 return false; 1410 } else if (!stack.back().ResolveValue(exe_ctx).AbsoluteValue()) { 1411 if (error_ptr) 1412 error_ptr->SetErrorString( 1413 "Failed to take the absolute value of the first stack item."); 1414 return false; 1415 } 1416 break; 1417 1418 // OPCODE: DW_OP_and 1419 // OPERANDS: none 1420 // DESCRIPTION: pops the top two stack values, performs a bitwise and 1421 // operation on the two, and pushes the result. 1422 case DW_OP_and: 1423 if (stack.size() < 2) { 1424 if (error_ptr) 1425 error_ptr->SetErrorString( 1426 "Expression stack needs at least 2 items for DW_OP_and."); 1427 return false; 1428 } else { 1429 tmp = stack.back(); 1430 stack.pop_back(); 1431 stack.back().ResolveValue(exe_ctx) = 1432 stack.back().ResolveValue(exe_ctx) & tmp.ResolveValue(exe_ctx); 1433 } 1434 break; 1435 1436 // OPCODE: DW_OP_div 1437 // OPERANDS: none 1438 // DESCRIPTION: pops the top two stack values, divides the former second 1439 // entry by the former top of the stack using signed division, and pushes 1440 // the result. 1441 case DW_OP_div: 1442 if (stack.size() < 2) { 1443 if (error_ptr) 1444 error_ptr->SetErrorString( 1445 "Expression stack needs at least 2 items for DW_OP_div."); 1446 return false; 1447 } else { 1448 tmp = stack.back(); 1449 if (tmp.ResolveValue(exe_ctx).IsZero()) { 1450 if (error_ptr) 1451 error_ptr->SetErrorString("Divide by zero."); 1452 return false; 1453 } else { 1454 stack.pop_back(); 1455 Scalar divisor, dividend; 1456 divisor = tmp.ResolveValue(exe_ctx); 1457 dividend = stack.back().ResolveValue(exe_ctx); 1458 divisor.MakeSigned(); 1459 dividend.MakeSigned(); 1460 stack.back() = dividend / divisor; 1461 if (!stack.back().ResolveValue(exe_ctx).IsValid()) { 1462 if (error_ptr) 1463 error_ptr->SetErrorString("Divide failed."); 1464 return false; 1465 } 1466 } 1467 } 1468 break; 1469 1470 // OPCODE: DW_OP_minus 1471 // OPERANDS: none 1472 // DESCRIPTION: pops the top two stack values, subtracts the former top 1473 // of the stack from the former second entry, and pushes the result. 1474 case DW_OP_minus: 1475 if (stack.size() < 2) { 1476 if (error_ptr) 1477 error_ptr->SetErrorString( 1478 "Expression stack needs at least 2 items for DW_OP_minus."); 1479 return false; 1480 } else { 1481 tmp = stack.back(); 1482 stack.pop_back(); 1483 stack.back().ResolveValue(exe_ctx) = 1484 stack.back().ResolveValue(exe_ctx) - tmp.ResolveValue(exe_ctx); 1485 } 1486 break; 1487 1488 // OPCODE: DW_OP_mod 1489 // OPERANDS: none 1490 // DESCRIPTION: pops the top two stack values and pushes the result of 1491 // the calculation: former second stack entry modulo the former top of the 1492 // stack. 1493 case DW_OP_mod: 1494 if (stack.size() < 2) { 1495 if (error_ptr) 1496 error_ptr->SetErrorString( 1497 "Expression stack needs at least 2 items for DW_OP_mod."); 1498 return false; 1499 } else { 1500 tmp = stack.back(); 1501 stack.pop_back(); 1502 stack.back().ResolveValue(exe_ctx) = 1503 stack.back().ResolveValue(exe_ctx) % tmp.ResolveValue(exe_ctx); 1504 } 1505 break; 1506 1507 // OPCODE: DW_OP_mul 1508 // OPERANDS: none 1509 // DESCRIPTION: pops the top two stack entries, multiplies them 1510 // together, and pushes the result. 1511 case DW_OP_mul: 1512 if (stack.size() < 2) { 1513 if (error_ptr) 1514 error_ptr->SetErrorString( 1515 "Expression stack needs at least 2 items for DW_OP_mul."); 1516 return false; 1517 } else { 1518 tmp = stack.back(); 1519 stack.pop_back(); 1520 stack.back().ResolveValue(exe_ctx) = 1521 stack.back().ResolveValue(exe_ctx) * tmp.ResolveValue(exe_ctx); 1522 } 1523 break; 1524 1525 // OPCODE: DW_OP_neg 1526 // OPERANDS: none 1527 // DESCRIPTION: pops the top stack entry, and pushes its negation. 1528 case DW_OP_neg: 1529 if (stack.empty()) { 1530 if (error_ptr) 1531 error_ptr->SetErrorString( 1532 "Expression stack needs at least 1 item for DW_OP_neg."); 1533 return false; 1534 } else { 1535 if (!stack.back().ResolveValue(exe_ctx).UnaryNegate()) { 1536 if (error_ptr) 1537 error_ptr->SetErrorString("Unary negate failed."); 1538 return false; 1539 } 1540 } 1541 break; 1542 1543 // OPCODE: DW_OP_not 1544 // OPERANDS: none 1545 // DESCRIPTION: pops the top stack entry, and pushes its bitwise 1546 // complement 1547 case DW_OP_not: 1548 if (stack.empty()) { 1549 if (error_ptr) 1550 error_ptr->SetErrorString( 1551 "Expression stack needs at least 1 item for DW_OP_not."); 1552 return false; 1553 } else { 1554 if (!stack.back().ResolveValue(exe_ctx).OnesComplement()) { 1555 if (error_ptr) 1556 error_ptr->SetErrorString("Logical NOT failed."); 1557 return false; 1558 } 1559 } 1560 break; 1561 1562 // OPCODE: DW_OP_or 1563 // OPERANDS: none 1564 // DESCRIPTION: pops the top two stack entries, performs a bitwise or 1565 // operation on the two, and pushes the result. 1566 case DW_OP_or: 1567 if (stack.size() < 2) { 1568 if (error_ptr) 1569 error_ptr->SetErrorString( 1570 "Expression stack needs at least 2 items for DW_OP_or."); 1571 return false; 1572 } else { 1573 tmp = stack.back(); 1574 stack.pop_back(); 1575 stack.back().ResolveValue(exe_ctx) = 1576 stack.back().ResolveValue(exe_ctx) | tmp.ResolveValue(exe_ctx); 1577 } 1578 break; 1579 1580 // OPCODE: DW_OP_plus 1581 // OPERANDS: none 1582 // DESCRIPTION: pops the top two stack entries, adds them together, and 1583 // pushes the result. 1584 case DW_OP_plus: 1585 if (stack.size() < 2) { 1586 if (error_ptr) 1587 error_ptr->SetErrorString( 1588 "Expression stack needs at least 2 items for DW_OP_plus."); 1589 return false; 1590 } else { 1591 tmp = stack.back(); 1592 stack.pop_back(); 1593 stack.back().GetScalar() += tmp.GetScalar(); 1594 } 1595 break; 1596 1597 // OPCODE: DW_OP_plus_uconst 1598 // OPERANDS: none 1599 // DESCRIPTION: pops the top stack entry, adds it to the unsigned LEB128 1600 // constant operand and pushes the result. 1601 case DW_OP_plus_uconst: 1602 if (stack.empty()) { 1603 if (error_ptr) 1604 error_ptr->SetErrorString( 1605 "Expression stack needs at least 1 item for DW_OP_plus_uconst."); 1606 return false; 1607 } else { 1608 const uint64_t uconst_value = opcodes.GetULEB128(&offset); 1609 // Implicit conversion from a UINT to a Scalar... 1610 stack.back().GetScalar() += uconst_value; 1611 if (!stack.back().GetScalar().IsValid()) { 1612 if (error_ptr) 1613 error_ptr->SetErrorString("DW_OP_plus_uconst failed."); 1614 return false; 1615 } 1616 } 1617 break; 1618 1619 // OPCODE: DW_OP_shl 1620 // OPERANDS: none 1621 // DESCRIPTION: pops the top two stack entries, shifts the former 1622 // second entry left by the number of bits specified by the former top of 1623 // the stack, and pushes the result. 1624 case DW_OP_shl: 1625 if (stack.size() < 2) { 1626 if (error_ptr) 1627 error_ptr->SetErrorString( 1628 "Expression stack needs at least 2 items for DW_OP_shl."); 1629 return false; 1630 } else { 1631 tmp = stack.back(); 1632 stack.pop_back(); 1633 stack.back().ResolveValue(exe_ctx) <<= tmp.ResolveValue(exe_ctx); 1634 } 1635 break; 1636 1637 // OPCODE: DW_OP_shr 1638 // OPERANDS: none 1639 // DESCRIPTION: pops the top two stack entries, shifts the former second 1640 // entry right logically (filling with zero bits) by the number of bits 1641 // specified by the former top of the stack, and pushes the result. 1642 case DW_OP_shr: 1643 if (stack.size() < 2) { 1644 if (error_ptr) 1645 error_ptr->SetErrorString( 1646 "Expression stack needs at least 2 items for DW_OP_shr."); 1647 return false; 1648 } else { 1649 tmp = stack.back(); 1650 stack.pop_back(); 1651 if (!stack.back().ResolveValue(exe_ctx).ShiftRightLogical( 1652 tmp.ResolveValue(exe_ctx))) { 1653 if (error_ptr) 1654 error_ptr->SetErrorString("DW_OP_shr failed."); 1655 return false; 1656 } 1657 } 1658 break; 1659 1660 // OPCODE: DW_OP_shra 1661 // OPERANDS: none 1662 // DESCRIPTION: pops the top two stack entries, shifts the former second 1663 // entry right arithmetically (divide the magnitude by 2, keep the same 1664 // sign for the result) by the number of bits specified by the former top 1665 // of the stack, and pushes the result. 1666 case DW_OP_shra: 1667 if (stack.size() < 2) { 1668 if (error_ptr) 1669 error_ptr->SetErrorString( 1670 "Expression stack needs at least 2 items for DW_OP_shra."); 1671 return false; 1672 } else { 1673 tmp = stack.back(); 1674 stack.pop_back(); 1675 stack.back().ResolveValue(exe_ctx) >>= tmp.ResolveValue(exe_ctx); 1676 } 1677 break; 1678 1679 // OPCODE: DW_OP_xor 1680 // OPERANDS: none 1681 // DESCRIPTION: pops the top two stack entries, performs the bitwise 1682 // exclusive-or operation on the two, and pushes the result. 1683 case DW_OP_xor: 1684 if (stack.size() < 2) { 1685 if (error_ptr) 1686 error_ptr->SetErrorString( 1687 "Expression stack needs at least 2 items for DW_OP_xor."); 1688 return false; 1689 } else { 1690 tmp = stack.back(); 1691 stack.pop_back(); 1692 stack.back().ResolveValue(exe_ctx) = 1693 stack.back().ResolveValue(exe_ctx) ^ tmp.ResolveValue(exe_ctx); 1694 } 1695 break; 1696 1697 // OPCODE: DW_OP_skip 1698 // OPERANDS: int16_t 1699 // DESCRIPTION: An unconditional branch. Its single operand is a 2-byte 1700 // signed integer constant. The 2-byte constant is the number of bytes of 1701 // the DWARF expression to skip forward or backward from the current 1702 // operation, beginning after the 2-byte constant. 1703 case DW_OP_skip: { 1704 int16_t skip_offset = (int16_t)opcodes.GetU16(&offset); 1705 lldb::offset_t new_offset = offset + skip_offset; 1706 // New offset can point at the end of the data, in this case we should 1707 // terminate the DWARF expression evaluation (will happen in the loop 1708 // condition). 1709 if (new_offset <= opcodes.GetByteSize()) 1710 offset = new_offset; 1711 else { 1712 if (error_ptr) 1713 error_ptr->SetErrorStringWithFormatv( 1714 "Invalid opcode offset in DW_OP_skip: {0}+({1}) > {2}", offset, 1715 skip_offset, opcodes.GetByteSize()); 1716 return false; 1717 } 1718 } break; 1719 1720 // OPCODE: DW_OP_bra 1721 // OPERANDS: int16_t 1722 // DESCRIPTION: A conditional branch. Its single operand is a 2-byte 1723 // signed integer constant. This operation pops the top of stack. If the 1724 // value popped is not the constant 0, the 2-byte constant operand is the 1725 // number of bytes of the DWARF expression to skip forward or backward from 1726 // the current operation, beginning after the 2-byte constant. 1727 case DW_OP_bra: 1728 if (stack.empty()) { 1729 if (error_ptr) 1730 error_ptr->SetErrorString( 1731 "Expression stack needs at least 1 item for DW_OP_bra."); 1732 return false; 1733 } else { 1734 tmp = stack.back(); 1735 stack.pop_back(); 1736 int16_t bra_offset = (int16_t)opcodes.GetU16(&offset); 1737 Scalar zero(0); 1738 if (tmp.ResolveValue(exe_ctx) != zero) { 1739 lldb::offset_t new_offset = offset + bra_offset; 1740 // New offset can point at the end of the data, in this case we should 1741 // terminate the DWARF expression evaluation (will happen in the loop 1742 // condition). 1743 if (new_offset <= opcodes.GetByteSize()) 1744 offset = new_offset; 1745 else { 1746 if (error_ptr) 1747 error_ptr->SetErrorStringWithFormatv( 1748 "Invalid opcode offset in DW_OP_bra: {0}+({1}) > {2}", offset, 1749 bra_offset, opcodes.GetByteSize()); 1750 return false; 1751 } 1752 } 1753 } 1754 break; 1755 1756 // OPCODE: DW_OP_eq 1757 // OPERANDS: none 1758 // DESCRIPTION: pops the top two stack values, compares using the 1759 // equals (==) operator. 1760 // STACK RESULT: push the constant value 1 onto the stack if the result 1761 // of the operation is true or the constant value 0 if the result of the 1762 // operation is false. 1763 case DW_OP_eq: 1764 if (stack.size() < 2) { 1765 if (error_ptr) 1766 error_ptr->SetErrorString( 1767 "Expression stack needs at least 2 items for DW_OP_eq."); 1768 return false; 1769 } else { 1770 tmp = stack.back(); 1771 stack.pop_back(); 1772 stack.back().ResolveValue(exe_ctx) = 1773 stack.back().ResolveValue(exe_ctx) == tmp.ResolveValue(exe_ctx); 1774 } 1775 break; 1776 1777 // OPCODE: DW_OP_ge 1778 // OPERANDS: none 1779 // DESCRIPTION: pops the top two stack values, compares using the 1780 // greater than or equal to (>=) operator. 1781 // STACK RESULT: push the constant value 1 onto the stack if the result 1782 // of the operation is true or the constant value 0 if the result of the 1783 // operation is false. 1784 case DW_OP_ge: 1785 if (stack.size() < 2) { 1786 if (error_ptr) 1787 error_ptr->SetErrorString( 1788 "Expression stack needs at least 2 items for DW_OP_ge."); 1789 return false; 1790 } else { 1791 tmp = stack.back(); 1792 stack.pop_back(); 1793 stack.back().ResolveValue(exe_ctx) = 1794 stack.back().ResolveValue(exe_ctx) >= tmp.ResolveValue(exe_ctx); 1795 } 1796 break; 1797 1798 // OPCODE: DW_OP_gt 1799 // OPERANDS: none 1800 // DESCRIPTION: pops the top two stack values, compares using the 1801 // greater than (>) operator. 1802 // STACK RESULT: push the constant value 1 onto the stack if the result 1803 // of the operation is true or the constant value 0 if the result of the 1804 // operation is false. 1805 case DW_OP_gt: 1806 if (stack.size() < 2) { 1807 if (error_ptr) 1808 error_ptr->SetErrorString( 1809 "Expression stack needs at least 2 items for DW_OP_gt."); 1810 return false; 1811 } else { 1812 tmp = stack.back(); 1813 stack.pop_back(); 1814 stack.back().ResolveValue(exe_ctx) = 1815 stack.back().ResolveValue(exe_ctx) > tmp.ResolveValue(exe_ctx); 1816 } 1817 break; 1818 1819 // OPCODE: DW_OP_le 1820 // OPERANDS: none 1821 // DESCRIPTION: pops the top two stack values, compares using the 1822 // less than or equal to (<=) operator. 1823 // STACK RESULT: push the constant value 1 onto the stack if the result 1824 // of the operation is true or the constant value 0 if the result of the 1825 // operation is false. 1826 case DW_OP_le: 1827 if (stack.size() < 2) { 1828 if (error_ptr) 1829 error_ptr->SetErrorString( 1830 "Expression stack needs at least 2 items for DW_OP_le."); 1831 return false; 1832 } else { 1833 tmp = stack.back(); 1834 stack.pop_back(); 1835 stack.back().ResolveValue(exe_ctx) = 1836 stack.back().ResolveValue(exe_ctx) <= tmp.ResolveValue(exe_ctx); 1837 } 1838 break; 1839 1840 // OPCODE: DW_OP_lt 1841 // OPERANDS: none 1842 // DESCRIPTION: pops the top two stack values, compares using the 1843 // less than (<) operator. 1844 // STACK RESULT: push the constant value 1 onto the stack if the result 1845 // of the operation is true or the constant value 0 if the result of the 1846 // operation is false. 1847 case DW_OP_lt: 1848 if (stack.size() < 2) { 1849 if (error_ptr) 1850 error_ptr->SetErrorString( 1851 "Expression stack needs at least 2 items for DW_OP_lt."); 1852 return false; 1853 } else { 1854 tmp = stack.back(); 1855 stack.pop_back(); 1856 stack.back().ResolveValue(exe_ctx) = 1857 stack.back().ResolveValue(exe_ctx) < tmp.ResolveValue(exe_ctx); 1858 } 1859 break; 1860 1861 // OPCODE: DW_OP_ne 1862 // OPERANDS: none 1863 // DESCRIPTION: pops the top two stack values, compares using the 1864 // not equal (!=) operator. 1865 // STACK RESULT: push the constant value 1 onto the stack if the result 1866 // of the operation is true or the constant value 0 if the result of the 1867 // operation is false. 1868 case DW_OP_ne: 1869 if (stack.size() < 2) { 1870 if (error_ptr) 1871 error_ptr->SetErrorString( 1872 "Expression stack needs at least 2 items for DW_OP_ne."); 1873 return false; 1874 } else { 1875 tmp = stack.back(); 1876 stack.pop_back(); 1877 stack.back().ResolveValue(exe_ctx) = 1878 stack.back().ResolveValue(exe_ctx) != tmp.ResolveValue(exe_ctx); 1879 } 1880 break; 1881 1882 // OPCODE: DW_OP_litn 1883 // OPERANDS: none 1884 // DESCRIPTION: encode the unsigned literal values from 0 through 31. 1885 // STACK RESULT: push the unsigned literal constant value onto the top 1886 // of the stack. 1887 case DW_OP_lit0: 1888 case DW_OP_lit1: 1889 case DW_OP_lit2: 1890 case DW_OP_lit3: 1891 case DW_OP_lit4: 1892 case DW_OP_lit5: 1893 case DW_OP_lit6: 1894 case DW_OP_lit7: 1895 case DW_OP_lit8: 1896 case DW_OP_lit9: 1897 case DW_OP_lit10: 1898 case DW_OP_lit11: 1899 case DW_OP_lit12: 1900 case DW_OP_lit13: 1901 case DW_OP_lit14: 1902 case DW_OP_lit15: 1903 case DW_OP_lit16: 1904 case DW_OP_lit17: 1905 case DW_OP_lit18: 1906 case DW_OP_lit19: 1907 case DW_OP_lit20: 1908 case DW_OP_lit21: 1909 case DW_OP_lit22: 1910 case DW_OP_lit23: 1911 case DW_OP_lit24: 1912 case DW_OP_lit25: 1913 case DW_OP_lit26: 1914 case DW_OP_lit27: 1915 case DW_OP_lit28: 1916 case DW_OP_lit29: 1917 case DW_OP_lit30: 1918 case DW_OP_lit31: 1919 stack.push_back(to_generic(op - DW_OP_lit0)); 1920 break; 1921 1922 // OPCODE: DW_OP_regN 1923 // OPERANDS: none 1924 // DESCRIPTION: Push the value in register n on the top of the stack. 1925 case DW_OP_reg0: 1926 case DW_OP_reg1: 1927 case DW_OP_reg2: 1928 case DW_OP_reg3: 1929 case DW_OP_reg4: 1930 case DW_OP_reg5: 1931 case DW_OP_reg6: 1932 case DW_OP_reg7: 1933 case DW_OP_reg8: 1934 case DW_OP_reg9: 1935 case DW_OP_reg10: 1936 case DW_OP_reg11: 1937 case DW_OP_reg12: 1938 case DW_OP_reg13: 1939 case DW_OP_reg14: 1940 case DW_OP_reg15: 1941 case DW_OP_reg16: 1942 case DW_OP_reg17: 1943 case DW_OP_reg18: 1944 case DW_OP_reg19: 1945 case DW_OP_reg20: 1946 case DW_OP_reg21: 1947 case DW_OP_reg22: 1948 case DW_OP_reg23: 1949 case DW_OP_reg24: 1950 case DW_OP_reg25: 1951 case DW_OP_reg26: 1952 case DW_OP_reg27: 1953 case DW_OP_reg28: 1954 case DW_OP_reg29: 1955 case DW_OP_reg30: 1956 case DW_OP_reg31: { 1957 dwarf4_location_description_kind = Register; 1958 reg_num = op - DW_OP_reg0; 1959 1960 if (ReadRegisterValueAsScalar(reg_ctx, reg_kind, reg_num, error_ptr, tmp)) 1961 stack.push_back(tmp); 1962 else 1963 return false; 1964 } break; 1965 // OPCODE: DW_OP_regx 1966 // OPERANDS: 1967 // ULEB128 literal operand that encodes the register. 1968 // DESCRIPTION: Push the value in register on the top of the stack. 1969 case DW_OP_regx: { 1970 dwarf4_location_description_kind = Register; 1971 reg_num = opcodes.GetULEB128(&offset); 1972 if (ReadRegisterValueAsScalar(reg_ctx, reg_kind, reg_num, error_ptr, tmp)) 1973 stack.push_back(tmp); 1974 else 1975 return false; 1976 } break; 1977 1978 // OPCODE: DW_OP_bregN 1979 // OPERANDS: 1980 // SLEB128 offset from register N 1981 // DESCRIPTION: Value is in memory at the address specified by register 1982 // N plus an offset. 1983 case DW_OP_breg0: 1984 case DW_OP_breg1: 1985 case DW_OP_breg2: 1986 case DW_OP_breg3: 1987 case DW_OP_breg4: 1988 case DW_OP_breg5: 1989 case DW_OP_breg6: 1990 case DW_OP_breg7: 1991 case DW_OP_breg8: 1992 case DW_OP_breg9: 1993 case DW_OP_breg10: 1994 case DW_OP_breg11: 1995 case DW_OP_breg12: 1996 case DW_OP_breg13: 1997 case DW_OP_breg14: 1998 case DW_OP_breg15: 1999 case DW_OP_breg16: 2000 case DW_OP_breg17: 2001 case DW_OP_breg18: 2002 case DW_OP_breg19: 2003 case DW_OP_breg20: 2004 case DW_OP_breg21: 2005 case DW_OP_breg22: 2006 case DW_OP_breg23: 2007 case DW_OP_breg24: 2008 case DW_OP_breg25: 2009 case DW_OP_breg26: 2010 case DW_OP_breg27: 2011 case DW_OP_breg28: 2012 case DW_OP_breg29: 2013 case DW_OP_breg30: 2014 case DW_OP_breg31: { 2015 reg_num = op - DW_OP_breg0; 2016 2017 if (ReadRegisterValueAsScalar(reg_ctx, reg_kind, reg_num, error_ptr, 2018 tmp)) { 2019 int64_t breg_offset = opcodes.GetSLEB128(&offset); 2020 tmp.ResolveValue(exe_ctx) += (uint64_t)breg_offset; 2021 tmp.ClearContext(); 2022 stack.push_back(tmp); 2023 stack.back().SetValueType(Value::ValueType::LoadAddress); 2024 } else 2025 return false; 2026 } break; 2027 // OPCODE: DW_OP_bregx 2028 // OPERANDS: 2 2029 // ULEB128 literal operand that encodes the register. 2030 // SLEB128 offset from register N 2031 // DESCRIPTION: Value is in memory at the address specified by register 2032 // N plus an offset. 2033 case DW_OP_bregx: { 2034 reg_num = opcodes.GetULEB128(&offset); 2035 2036 if (ReadRegisterValueAsScalar(reg_ctx, reg_kind, reg_num, error_ptr, 2037 tmp)) { 2038 int64_t breg_offset = opcodes.GetSLEB128(&offset); 2039 tmp.ResolveValue(exe_ctx) += (uint64_t)breg_offset; 2040 tmp.ClearContext(); 2041 stack.push_back(tmp); 2042 stack.back().SetValueType(Value::ValueType::LoadAddress); 2043 } else 2044 return false; 2045 } break; 2046 2047 case DW_OP_fbreg: 2048 if (exe_ctx) { 2049 if (frame) { 2050 Scalar value; 2051 if (frame->GetFrameBaseValue(value, error_ptr)) { 2052 int64_t fbreg_offset = opcodes.GetSLEB128(&offset); 2053 value += fbreg_offset; 2054 stack.push_back(value); 2055 stack.back().SetValueType(Value::ValueType::LoadAddress); 2056 } else 2057 return false; 2058 } else { 2059 if (error_ptr) 2060 error_ptr->SetErrorString( 2061 "Invalid stack frame in context for DW_OP_fbreg opcode."); 2062 return false; 2063 } 2064 } else { 2065 if (error_ptr) 2066 error_ptr->SetErrorString( 2067 "NULL execution context for DW_OP_fbreg.\n"); 2068 return false; 2069 } 2070 2071 break; 2072 2073 // OPCODE: DW_OP_nop 2074 // OPERANDS: none 2075 // DESCRIPTION: A place holder. It has no effect on the location stack 2076 // or any of its values. 2077 case DW_OP_nop: 2078 break; 2079 2080 // OPCODE: DW_OP_piece 2081 // OPERANDS: 1 2082 // ULEB128: byte size of the piece 2083 // DESCRIPTION: The operand describes the size in bytes of the piece of 2084 // the object referenced by the DWARF expression whose result is at the top 2085 // of the stack. If the piece is located in a register, but does not occupy 2086 // the entire register, the placement of the piece within that register is 2087 // defined by the ABI. 2088 // 2089 // Many compilers store a single variable in sets of registers, or store a 2090 // variable partially in memory and partially in registers. DW_OP_piece 2091 // provides a way of describing how large a part of a variable a particular 2092 // DWARF expression refers to. 2093 case DW_OP_piece: { 2094 LocationDescriptionKind piece_locdesc = dwarf4_location_description_kind; 2095 // Reset for the next piece. 2096 dwarf4_location_description_kind = Memory; 2097 2098 const uint64_t piece_byte_size = opcodes.GetULEB128(&offset); 2099 2100 if (piece_byte_size > 0) { 2101 Value curr_piece; 2102 2103 if (stack.empty()) { 2104 UpdateValueTypeFromLocationDescription( 2105 log, dwarf_cu, LocationDescriptionKind::Empty); 2106 // In a multi-piece expression, this means that the current piece is 2107 // not available. Fill with zeros for now by resizing the data and 2108 // appending it 2109 curr_piece.ResizeData(piece_byte_size); 2110 // Note that "0" is not a correct value for the unknown bits. 2111 // It would be better to also return a mask of valid bits together 2112 // with the expression result, so the debugger can print missing 2113 // members as "<optimized out>" or something. 2114 ::memset(curr_piece.GetBuffer().GetBytes(), 0, piece_byte_size); 2115 pieces.AppendDataToHostBuffer(curr_piece); 2116 } else { 2117 Status error; 2118 // Extract the current piece into "curr_piece" 2119 Value curr_piece_source_value(stack.back()); 2120 stack.pop_back(); 2121 UpdateValueTypeFromLocationDescription(log, dwarf_cu, piece_locdesc, 2122 &curr_piece_source_value); 2123 2124 const Value::ValueType curr_piece_source_value_type = 2125 curr_piece_source_value.GetValueType(); 2126 switch (curr_piece_source_value_type) { 2127 case Value::ValueType::Invalid: 2128 return false; 2129 case Value::ValueType::LoadAddress: 2130 if (process) { 2131 if (curr_piece.ResizeData(piece_byte_size) == piece_byte_size) { 2132 lldb::addr_t load_addr = 2133 curr_piece_source_value.GetScalar().ULongLong( 2134 LLDB_INVALID_ADDRESS); 2135 if (process->ReadMemory( 2136 load_addr, curr_piece.GetBuffer().GetBytes(), 2137 piece_byte_size, error) != piece_byte_size) { 2138 if (error_ptr) 2139 error_ptr->SetErrorStringWithFormat( 2140 "failed to read memory DW_OP_piece(%" PRIu64 2141 ") from 0x%" PRIx64, 2142 piece_byte_size, load_addr); 2143 return false; 2144 } 2145 } else { 2146 if (error_ptr) 2147 error_ptr->SetErrorStringWithFormat( 2148 "failed to resize the piece memory buffer for " 2149 "DW_OP_piece(%" PRIu64 ")", 2150 piece_byte_size); 2151 return false; 2152 } 2153 } 2154 break; 2155 2156 case Value::ValueType::FileAddress: 2157 case Value::ValueType::HostAddress: 2158 if (error_ptr) { 2159 lldb::addr_t addr = curr_piece_source_value.GetScalar().ULongLong( 2160 LLDB_INVALID_ADDRESS); 2161 error_ptr->SetErrorStringWithFormat( 2162 "failed to read memory DW_OP_piece(%" PRIu64 2163 ") from %s address 0x%" PRIx64, 2164 piece_byte_size, curr_piece_source_value.GetValueType() == 2165 Value::ValueType::FileAddress 2166 ? "file" 2167 : "host", 2168 addr); 2169 } 2170 return false; 2171 2172 case Value::ValueType::Scalar: { 2173 uint32_t bit_size = piece_byte_size * 8; 2174 uint32_t bit_offset = 0; 2175 Scalar &scalar = curr_piece_source_value.GetScalar(); 2176 if (!scalar.ExtractBitfield( 2177 bit_size, bit_offset)) { 2178 if (error_ptr) 2179 error_ptr->SetErrorStringWithFormat( 2180 "unable to extract %" PRIu64 " bytes from a %" PRIu64 2181 " byte scalar value.", 2182 piece_byte_size, 2183 (uint64_t)curr_piece_source_value.GetScalar() 2184 .GetByteSize()); 2185 return false; 2186 } 2187 // Create curr_piece with bit_size. By default Scalar 2188 // grows to the nearest host integer type. 2189 llvm::APInt fail_value(1, 0, false); 2190 llvm::APInt ap_int = scalar.UInt128(fail_value); 2191 assert(ap_int.getBitWidth() >= bit_size); 2192 llvm::ArrayRef<uint64_t> buf{ap_int.getRawData(), 2193 ap_int.getNumWords()}; 2194 curr_piece.GetScalar() = Scalar(llvm::APInt(bit_size, buf)); 2195 } break; 2196 } 2197 2198 // Check if this is the first piece? 2199 if (op_piece_offset == 0) { 2200 // This is the first piece, we should push it back onto the stack 2201 // so subsequent pieces will be able to access this piece and add 2202 // to it. 2203 if (pieces.AppendDataToHostBuffer(curr_piece) == 0) { 2204 if (error_ptr) 2205 error_ptr->SetErrorString("failed to append piece data"); 2206 return false; 2207 } 2208 } else { 2209 // If this is the second or later piece there should be a value on 2210 // the stack. 2211 if (pieces.GetBuffer().GetByteSize() != op_piece_offset) { 2212 if (error_ptr) 2213 error_ptr->SetErrorStringWithFormat( 2214 "DW_OP_piece for offset %" PRIu64 2215 " but top of stack is of size %" PRIu64, 2216 op_piece_offset, pieces.GetBuffer().GetByteSize()); 2217 return false; 2218 } 2219 2220 if (pieces.AppendDataToHostBuffer(curr_piece) == 0) { 2221 if (error_ptr) 2222 error_ptr->SetErrorString("failed to append piece data"); 2223 return false; 2224 } 2225 } 2226 } 2227 op_piece_offset += piece_byte_size; 2228 } 2229 } break; 2230 2231 case DW_OP_bit_piece: // 0x9d ULEB128 bit size, ULEB128 bit offset (DWARF3); 2232 if (stack.size() < 1) { 2233 UpdateValueTypeFromLocationDescription(log, dwarf_cu, 2234 LocationDescriptionKind::Empty); 2235 // Reset for the next piece. 2236 dwarf4_location_description_kind = Memory; 2237 if (error_ptr) 2238 error_ptr->SetErrorString( 2239 "Expression stack needs at least 1 item for DW_OP_bit_piece."); 2240 return false; 2241 } else { 2242 UpdateValueTypeFromLocationDescription( 2243 log, dwarf_cu, dwarf4_location_description_kind, &stack.back()); 2244 // Reset for the next piece. 2245 dwarf4_location_description_kind = Memory; 2246 const uint64_t piece_bit_size = opcodes.GetULEB128(&offset); 2247 const uint64_t piece_bit_offset = opcodes.GetULEB128(&offset); 2248 switch (stack.back().GetValueType()) { 2249 case Value::ValueType::Invalid: 2250 return false; 2251 case Value::ValueType::Scalar: { 2252 if (!stack.back().GetScalar().ExtractBitfield(piece_bit_size, 2253 piece_bit_offset)) { 2254 if (error_ptr) 2255 error_ptr->SetErrorStringWithFormat( 2256 "unable to extract %" PRIu64 " bit value with %" PRIu64 2257 " bit offset from a %" PRIu64 " bit scalar value.", 2258 piece_bit_size, piece_bit_offset, 2259 (uint64_t)(stack.back().GetScalar().GetByteSize() * 8)); 2260 return false; 2261 } 2262 } break; 2263 2264 case Value::ValueType::FileAddress: 2265 case Value::ValueType::LoadAddress: 2266 case Value::ValueType::HostAddress: 2267 if (error_ptr) { 2268 error_ptr->SetErrorStringWithFormat( 2269 "unable to extract DW_OP_bit_piece(bit_size = %" PRIu64 2270 ", bit_offset = %" PRIu64 ") from an address value.", 2271 piece_bit_size, piece_bit_offset); 2272 } 2273 return false; 2274 } 2275 } 2276 break; 2277 2278 // OPCODE: DW_OP_implicit_value 2279 // OPERANDS: 2 2280 // ULEB128 size of the value block in bytes 2281 // uint8_t* block bytes encoding value in target's memory 2282 // representation 2283 // DESCRIPTION: Value is immediately stored in block in the debug info with 2284 // the memory representation of the target. 2285 case DW_OP_implicit_value: { 2286 dwarf4_location_description_kind = Implicit; 2287 2288 const uint32_t len = opcodes.GetULEB128(&offset); 2289 const void *data = opcodes.GetData(&offset, len); 2290 2291 if (!data) { 2292 LLDB_LOG(log, "Evaluate_DW_OP_implicit_value: could not be read data"); 2293 LLDB_ERRORF(error_ptr, "Could not evaluate %s.", 2294 DW_OP_value_to_name(op)); 2295 return false; 2296 } 2297 2298 Value result(data, len); 2299 stack.push_back(result); 2300 break; 2301 } 2302 2303 case DW_OP_implicit_pointer: { 2304 dwarf4_location_description_kind = Implicit; 2305 LLDB_ERRORF(error_ptr, "Could not evaluate %s.", DW_OP_value_to_name(op)); 2306 return false; 2307 } 2308 2309 // OPCODE: DW_OP_push_object_address 2310 // OPERANDS: none 2311 // DESCRIPTION: Pushes the address of the object currently being 2312 // evaluated as part of evaluation of a user presented expression. This 2313 // object may correspond to an independent variable described by its own 2314 // DIE or it may be a component of an array, structure, or class whose 2315 // address has been dynamically determined by an earlier step during user 2316 // expression evaluation. 2317 case DW_OP_push_object_address: 2318 if (object_address_ptr) 2319 stack.push_back(*object_address_ptr); 2320 else { 2321 if (error_ptr) 2322 error_ptr->SetErrorString("DW_OP_push_object_address used without " 2323 "specifying an object address"); 2324 return false; 2325 } 2326 break; 2327 2328 // OPCODE: DW_OP_call2 2329 // OPERANDS: 2330 // uint16_t compile unit relative offset of a DIE 2331 // DESCRIPTION: Performs subroutine calls during evaluation 2332 // of a DWARF expression. The operand is the 2-byte unsigned offset of a 2333 // debugging information entry in the current compilation unit. 2334 // 2335 // Operand interpretation is exactly like that for DW_FORM_ref2. 2336 // 2337 // This operation transfers control of DWARF expression evaluation to the 2338 // DW_AT_location attribute of the referenced DIE. If there is no such 2339 // attribute, then there is no effect. Execution of the DWARF expression of 2340 // a DW_AT_location attribute may add to and/or remove from values on the 2341 // stack. Execution returns to the point following the call when the end of 2342 // the attribute is reached. Values on the stack at the time of the call 2343 // may be used as parameters by the called expression and values left on 2344 // the stack by the called expression may be used as return values by prior 2345 // agreement between the calling and called expressions. 2346 case DW_OP_call2: 2347 if (error_ptr) 2348 error_ptr->SetErrorString("Unimplemented opcode DW_OP_call2."); 2349 return false; 2350 // OPCODE: DW_OP_call4 2351 // OPERANDS: 1 2352 // uint32_t compile unit relative offset of a DIE 2353 // DESCRIPTION: Performs a subroutine call during evaluation of a DWARF 2354 // expression. For DW_OP_call4, the operand is a 4-byte unsigned offset of 2355 // a debugging information entry in the current compilation unit. 2356 // 2357 // Operand interpretation DW_OP_call4 is exactly like that for 2358 // DW_FORM_ref4. 2359 // 2360 // This operation transfers control of DWARF expression evaluation to the 2361 // DW_AT_location attribute of the referenced DIE. If there is no such 2362 // attribute, then there is no effect. Execution of the DWARF expression of 2363 // a DW_AT_location attribute may add to and/or remove from values on the 2364 // stack. Execution returns to the point following the call when the end of 2365 // the attribute is reached. Values on the stack at the time of the call 2366 // may be used as parameters by the called expression and values left on 2367 // the stack by the called expression may be used as return values by prior 2368 // agreement between the calling and called expressions. 2369 case DW_OP_call4: 2370 if (error_ptr) 2371 error_ptr->SetErrorString("Unimplemented opcode DW_OP_call4."); 2372 return false; 2373 2374 // OPCODE: DW_OP_stack_value 2375 // OPERANDS: None 2376 // DESCRIPTION: Specifies that the object does not exist in memory but 2377 // rather is a constant value. The value from the top of the stack is the 2378 // value to be used. This is the actual object value and not the location. 2379 case DW_OP_stack_value: 2380 dwarf4_location_description_kind = Implicit; 2381 if (stack.empty()) { 2382 if (error_ptr) 2383 error_ptr->SetErrorString( 2384 "Expression stack needs at least 1 item for DW_OP_stack_value."); 2385 return false; 2386 } 2387 stack.back().SetValueType(Value::ValueType::Scalar); 2388 break; 2389 2390 // OPCODE: DW_OP_convert 2391 // OPERANDS: 1 2392 // A ULEB128 that is either a DIE offset of a 2393 // DW_TAG_base_type or 0 for the generic (pointer-sized) type. 2394 // 2395 // DESCRIPTION: Pop the top stack element, convert it to a 2396 // different type, and push the result. 2397 case DW_OP_convert: { 2398 if (stack.size() < 1) { 2399 if (error_ptr) 2400 error_ptr->SetErrorString( 2401 "Expression stack needs at least 1 item for DW_OP_convert."); 2402 return false; 2403 } 2404 const uint64_t die_offset = opcodes.GetULEB128(&offset); 2405 uint64_t bit_size; 2406 bool sign; 2407 if (die_offset == 0) { 2408 // The generic type has the size of an address on the target 2409 // machine and an unspecified signedness. Scalar has no 2410 // "unspecified signedness", so we use unsigned types. 2411 if (!module_sp) { 2412 if (error_ptr) 2413 error_ptr->SetErrorString("No module"); 2414 return false; 2415 } 2416 sign = false; 2417 bit_size = module_sp->GetArchitecture().GetAddressByteSize() * 8; 2418 if (!bit_size) { 2419 if (error_ptr) 2420 error_ptr->SetErrorString("unspecified architecture"); 2421 return false; 2422 } 2423 } else { 2424 // Retrieve the type DIE that the value is being converted to. This 2425 // offset is compile unit relative so we need to fix it up. 2426 const uint64_t abs_die_offset = die_offset + dwarf_cu->GetOffset(); 2427 // FIXME: the constness has annoying ripple effects. 2428 DWARFDIE die = const_cast<DWARFUnit *>(dwarf_cu)->GetDIE(abs_die_offset); 2429 if (!die) { 2430 if (error_ptr) 2431 error_ptr->SetErrorString("Cannot resolve DW_OP_convert type DIE"); 2432 return false; 2433 } 2434 uint64_t encoding = 2435 die.GetAttributeValueAsUnsigned(DW_AT_encoding, DW_ATE_hi_user); 2436 bit_size = die.GetAttributeValueAsUnsigned(DW_AT_byte_size, 0) * 8; 2437 if (!bit_size) 2438 bit_size = die.GetAttributeValueAsUnsigned(DW_AT_bit_size, 0); 2439 if (!bit_size) { 2440 if (error_ptr) 2441 error_ptr->SetErrorString("Unsupported type size in DW_OP_convert"); 2442 return false; 2443 } 2444 switch (encoding) { 2445 case DW_ATE_signed: 2446 case DW_ATE_signed_char: 2447 sign = true; 2448 break; 2449 case DW_ATE_unsigned: 2450 case DW_ATE_unsigned_char: 2451 sign = false; 2452 break; 2453 default: 2454 if (error_ptr) 2455 error_ptr->SetErrorString("Unsupported encoding in DW_OP_convert"); 2456 return false; 2457 } 2458 } 2459 Scalar &top = stack.back().ResolveValue(exe_ctx); 2460 top.TruncOrExtendTo(bit_size, sign); 2461 break; 2462 } 2463 2464 // OPCODE: DW_OP_call_frame_cfa 2465 // OPERANDS: None 2466 // DESCRIPTION: Specifies a DWARF expression that pushes the value of 2467 // the canonical frame address consistent with the call frame information 2468 // located in .debug_frame (or in the FDEs of the eh_frame section). 2469 case DW_OP_call_frame_cfa: 2470 if (frame) { 2471 // Note that we don't have to parse FDEs because this DWARF expression 2472 // is commonly evaluated with a valid stack frame. 2473 StackID id = frame->GetStackID(); 2474 addr_t cfa = id.GetCallFrameAddress(); 2475 if (cfa != LLDB_INVALID_ADDRESS) { 2476 stack.push_back(Scalar(cfa)); 2477 stack.back().SetValueType(Value::ValueType::LoadAddress); 2478 } else if (error_ptr) 2479 error_ptr->SetErrorString("Stack frame does not include a canonical " 2480 "frame address for DW_OP_call_frame_cfa " 2481 "opcode."); 2482 } else { 2483 if (error_ptr) 2484 error_ptr->SetErrorString("Invalid stack frame in context for " 2485 "DW_OP_call_frame_cfa opcode."); 2486 return false; 2487 } 2488 break; 2489 2490 // OPCODE: DW_OP_form_tls_address (or the old pre-DWARFv3 vendor extension 2491 // opcode, DW_OP_GNU_push_tls_address) 2492 // OPERANDS: none 2493 // DESCRIPTION: Pops a TLS offset from the stack, converts it to 2494 // an address in the current thread's thread-local storage block, and 2495 // pushes it on the stack. 2496 case DW_OP_form_tls_address: 2497 case DW_OP_GNU_push_tls_address: { 2498 if (stack.size() < 1) { 2499 if (error_ptr) { 2500 if (op == DW_OP_form_tls_address) 2501 error_ptr->SetErrorString( 2502 "DW_OP_form_tls_address needs an argument."); 2503 else 2504 error_ptr->SetErrorString( 2505 "DW_OP_GNU_push_tls_address needs an argument."); 2506 } 2507 return false; 2508 } 2509 2510 if (!exe_ctx || !module_sp) { 2511 if (error_ptr) 2512 error_ptr->SetErrorString("No context to evaluate TLS within."); 2513 return false; 2514 } 2515 2516 Thread *thread = exe_ctx->GetThreadPtr(); 2517 if (!thread) { 2518 if (error_ptr) 2519 error_ptr->SetErrorString("No thread to evaluate TLS within."); 2520 return false; 2521 } 2522 2523 // Lookup the TLS block address for this thread and module. 2524 const addr_t tls_file_addr = 2525 stack.back().GetScalar().ULongLong(LLDB_INVALID_ADDRESS); 2526 const addr_t tls_load_addr = 2527 thread->GetThreadLocalData(module_sp, tls_file_addr); 2528 2529 if (tls_load_addr == LLDB_INVALID_ADDRESS) { 2530 if (error_ptr) 2531 error_ptr->SetErrorString( 2532 "No TLS data currently exists for this thread."); 2533 return false; 2534 } 2535 2536 stack.back().GetScalar() = tls_load_addr; 2537 stack.back().SetValueType(Value::ValueType::LoadAddress); 2538 } break; 2539 2540 // OPCODE: DW_OP_addrx (DW_OP_GNU_addr_index is the legacy name.) 2541 // OPERANDS: 1 2542 // ULEB128: index to the .debug_addr section 2543 // DESCRIPTION: Pushes an address to the stack from the .debug_addr 2544 // section with the base address specified by the DW_AT_addr_base attribute 2545 // and the 0 based index is the ULEB128 encoded index. 2546 case DW_OP_addrx: 2547 case DW_OP_GNU_addr_index: { 2548 if (!dwarf_cu) { 2549 if (error_ptr) 2550 error_ptr->SetErrorString("DW_OP_GNU_addr_index found without a " 2551 "compile unit being specified"); 2552 return false; 2553 } 2554 uint64_t index = opcodes.GetULEB128(&offset); 2555 lldb::addr_t value = dwarf_cu->ReadAddressFromDebugAddrSection(index); 2556 stack.push_back(Scalar(value)); 2557 if (target && 2558 target->GetArchitecture().GetCore() == ArchSpec::eCore_wasm32) { 2559 // wasm file sections aren't mapped into memory, therefore addresses can 2560 // never point into a file section and are always LoadAddresses. 2561 stack.back().SetValueType(Value::ValueType::LoadAddress); 2562 } else { 2563 stack.back().SetValueType(Value::ValueType::FileAddress); 2564 } 2565 } break; 2566 2567 // OPCODE: DW_OP_GNU_const_index 2568 // OPERANDS: 1 2569 // ULEB128: index to the .debug_addr section 2570 // DESCRIPTION: Pushes an constant with the size of a machine address to 2571 // the stack from the .debug_addr section with the base address specified 2572 // by the DW_AT_addr_base attribute and the 0 based index is the ULEB128 2573 // encoded index. 2574 case DW_OP_GNU_const_index: { 2575 if (!dwarf_cu) { 2576 if (error_ptr) 2577 error_ptr->SetErrorString("DW_OP_GNU_const_index found without a " 2578 "compile unit being specified"); 2579 return false; 2580 } 2581 uint64_t index = opcodes.GetULEB128(&offset); 2582 lldb::addr_t value = dwarf_cu->ReadAddressFromDebugAddrSection(index); 2583 stack.push_back(Scalar(value)); 2584 } break; 2585 2586 case DW_OP_GNU_entry_value: 2587 case DW_OP_entry_value: { 2588 if (!Evaluate_DW_OP_entry_value(stack, exe_ctx, reg_ctx, opcodes, offset, 2589 error_ptr, log)) { 2590 LLDB_ERRORF(error_ptr, "Could not evaluate %s.", 2591 DW_OP_value_to_name(op)); 2592 return false; 2593 } 2594 break; 2595 } 2596 2597 default: 2598 if (dwarf_cu) { 2599 if (dwarf_cu->GetSymbolFileDWARF().ParseVendorDWARFOpcode( 2600 op, opcodes, offset, stack)) { 2601 break; 2602 } 2603 } 2604 if (error_ptr) 2605 error_ptr->SetErrorStringWithFormatv( 2606 "Unhandled opcode {0} in DWARFExpression", LocationAtom(op)); 2607 return false; 2608 } 2609 } 2610 2611 if (stack.empty()) { 2612 // Nothing on the stack, check if we created a piece value from DW_OP_piece 2613 // or DW_OP_bit_piece opcodes 2614 if (pieces.GetBuffer().GetByteSize()) { 2615 result = pieces; 2616 return true; 2617 } 2618 if (error_ptr) 2619 error_ptr->SetErrorString("Stack empty after evaluation."); 2620 return false; 2621 } 2622 2623 UpdateValueTypeFromLocationDescription( 2624 log, dwarf_cu, dwarf4_location_description_kind, &stack.back()); 2625 2626 if (log && log->GetVerbose()) { 2627 size_t count = stack.size(); 2628 LLDB_LOGF(log, 2629 "Stack after operation has %" PRIu64 " values:", (uint64_t)count); 2630 for (size_t i = 0; i < count; ++i) { 2631 StreamString new_value; 2632 new_value.Printf("[%" PRIu64 "]", (uint64_t)i); 2633 stack[i].Dump(&new_value); 2634 LLDB_LOGF(log, " %s", new_value.GetData()); 2635 } 2636 } 2637 result = stack.back(); 2638 return true; // Return true on success 2639 } 2640 2641 bool DWARFExpression::ParseDWARFLocationList( 2642 const DWARFUnit *dwarf_cu, const DataExtractor &data, 2643 DWARFExpressionList *location_list) { 2644 location_list->Clear(); 2645 std::unique_ptr<llvm::DWARFLocationTable> loctable_up = 2646 dwarf_cu->GetLocationTable(data); 2647 Log *log = GetLog(LLDBLog::Expressions); 2648 auto lookup_addr = 2649 [&](uint32_t index) -> std::optional<llvm::object::SectionedAddress> { 2650 addr_t address = dwarf_cu->ReadAddressFromDebugAddrSection(index); 2651 if (address == LLDB_INVALID_ADDRESS) 2652 return std::nullopt; 2653 return llvm::object::SectionedAddress{address}; 2654 }; 2655 auto process_list = [&](llvm::Expected<llvm::DWARFLocationExpression> loc) { 2656 if (!loc) { 2657 LLDB_LOG_ERROR(log, loc.takeError(), "{0}"); 2658 return true; 2659 } 2660 auto buffer_sp = 2661 std::make_shared<DataBufferHeap>(loc->Expr.data(), loc->Expr.size()); 2662 DWARFExpression expr = DWARFExpression(DataExtractor( 2663 buffer_sp, data.GetByteOrder(), data.GetAddressByteSize())); 2664 location_list->AddExpression(loc->Range->LowPC, loc->Range->HighPC, expr); 2665 return true; 2666 }; 2667 llvm::Error error = loctable_up->visitAbsoluteLocationList( 2668 0, llvm::object::SectionedAddress{dwarf_cu->GetBaseAddress()}, 2669 lookup_addr, process_list); 2670 location_list->Sort(); 2671 if (error) { 2672 LLDB_LOG_ERROR(log, std::move(error), "{0}"); 2673 return false; 2674 } 2675 return true; 2676 } 2677 2678 bool DWARFExpression::MatchesOperand( 2679 StackFrame &frame, const Instruction::Operand &operand) const { 2680 using namespace OperandMatchers; 2681 2682 RegisterContextSP reg_ctx_sp = frame.GetRegisterContext(); 2683 if (!reg_ctx_sp) { 2684 return false; 2685 } 2686 2687 DataExtractor opcodes(m_data); 2688 2689 lldb::offset_t op_offset = 0; 2690 uint8_t opcode = opcodes.GetU8(&op_offset); 2691 2692 if (opcode == DW_OP_fbreg) { 2693 int64_t offset = opcodes.GetSLEB128(&op_offset); 2694 2695 DWARFExpressionList *fb_expr = frame.GetFrameBaseExpression(nullptr); 2696 if (!fb_expr) { 2697 return false; 2698 } 2699 2700 auto recurse = [&frame, fb_expr](const Instruction::Operand &child) { 2701 return fb_expr->MatchesOperand(frame, child); 2702 }; 2703 2704 if (!offset && 2705 MatchUnaryOp(MatchOpType(Instruction::Operand::Type::Dereference), 2706 recurse)(operand)) { 2707 return true; 2708 } 2709 2710 return MatchUnaryOp( 2711 MatchOpType(Instruction::Operand::Type::Dereference), 2712 MatchBinaryOp(MatchOpType(Instruction::Operand::Type::Sum), 2713 MatchImmOp(offset), recurse))(operand); 2714 } 2715 2716 bool dereference = false; 2717 const RegisterInfo *reg = nullptr; 2718 int64_t offset = 0; 2719 2720 if (opcode >= DW_OP_reg0 && opcode <= DW_OP_reg31) { 2721 reg = reg_ctx_sp->GetRegisterInfo(m_reg_kind, opcode - DW_OP_reg0); 2722 } else if (opcode >= DW_OP_breg0 && opcode <= DW_OP_breg31) { 2723 offset = opcodes.GetSLEB128(&op_offset); 2724 reg = reg_ctx_sp->GetRegisterInfo(m_reg_kind, opcode - DW_OP_breg0); 2725 } else if (opcode == DW_OP_regx) { 2726 uint32_t reg_num = static_cast<uint32_t>(opcodes.GetULEB128(&op_offset)); 2727 reg = reg_ctx_sp->GetRegisterInfo(m_reg_kind, reg_num); 2728 } else if (opcode == DW_OP_bregx) { 2729 uint32_t reg_num = static_cast<uint32_t>(opcodes.GetULEB128(&op_offset)); 2730 offset = opcodes.GetSLEB128(&op_offset); 2731 reg = reg_ctx_sp->GetRegisterInfo(m_reg_kind, reg_num); 2732 } else { 2733 return false; 2734 } 2735 2736 if (!reg) { 2737 return false; 2738 } 2739 2740 if (dereference) { 2741 if (!offset && 2742 MatchUnaryOp(MatchOpType(Instruction::Operand::Type::Dereference), 2743 MatchRegOp(*reg))(operand)) { 2744 return true; 2745 } 2746 2747 return MatchUnaryOp( 2748 MatchOpType(Instruction::Operand::Type::Dereference), 2749 MatchBinaryOp(MatchOpType(Instruction::Operand::Type::Sum), 2750 MatchRegOp(*reg), 2751 MatchImmOp(offset)))(operand); 2752 } else { 2753 return MatchRegOp(*reg)(operand); 2754 } 2755 } 2756