1 //===-- DWARFExpression.cpp -----------------------------------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 #include "lldb/Expression/DWARFExpression.h" 10 11 #include <cinttypes> 12 13 #include <optional> 14 #include <vector> 15 16 #include "lldb/Core/Module.h" 17 #include "lldb/Core/Value.h" 18 #include "lldb/Core/dwarf.h" 19 #include "lldb/Utility/DataEncoder.h" 20 #include "lldb/Utility/LLDBLog.h" 21 #include "lldb/Utility/Log.h" 22 #include "lldb/Utility/RegisterValue.h" 23 #include "lldb/Utility/Scalar.h" 24 #include "lldb/Utility/StreamString.h" 25 #include "lldb/Utility/VMRange.h" 26 27 #include "lldb/Host/Host.h" 28 #include "lldb/Utility/Endian.h" 29 30 #include "lldb/Symbol/Function.h" 31 32 #include "lldb/Target/ABI.h" 33 #include "lldb/Target/ExecutionContext.h" 34 #include "lldb/Target/Process.h" 35 #include "lldb/Target/RegisterContext.h" 36 #include "lldb/Target/StackFrame.h" 37 #include "lldb/Target/StackID.h" 38 #include "lldb/Target/Target.h" 39 #include "lldb/Target/Thread.h" 40 #include "llvm/DebugInfo/DWARF/DWARFDebugLoc.h" 41 #include "llvm/DebugInfo/DWARF/DWARFExpression.h" 42 43 #include "Plugins/SymbolFile/DWARF/DWARFUnit.h" 44 45 using namespace lldb; 46 using namespace lldb_private; 47 using namespace lldb_private::dwarf; 48 using namespace lldb_private::plugin::dwarf; 49 50 // DWARFExpression constructor 51 DWARFExpression::DWARFExpression() : m_data() {} 52 53 DWARFExpression::DWARFExpression(const DataExtractor &data) : m_data(data) {} 54 55 // Destructor 56 DWARFExpression::~DWARFExpression() = default; 57 58 bool DWARFExpression::IsValid() const { return m_data.GetByteSize() > 0; } 59 60 void DWARFExpression::UpdateValue(uint64_t const_value, 61 lldb::offset_t const_value_byte_size, 62 uint8_t addr_byte_size) { 63 if (!const_value_byte_size) 64 return; 65 66 m_data.SetData( 67 DataBufferSP(new DataBufferHeap(&const_value, const_value_byte_size))); 68 m_data.SetByteOrder(endian::InlHostByteOrder()); 69 m_data.SetAddressByteSize(addr_byte_size); 70 } 71 72 void DWARFExpression::DumpLocation(Stream *s, lldb::DescriptionLevel level, 73 ABI *abi) const { 74 auto *MCRegInfo = abi ? &abi->GetMCRegisterInfo() : nullptr; 75 auto GetRegName = [&MCRegInfo](uint64_t DwarfRegNum, 76 bool IsEH) -> llvm::StringRef { 77 if (!MCRegInfo) 78 return {}; 79 if (std::optional<unsigned> LLVMRegNum = 80 MCRegInfo->getLLVMRegNum(DwarfRegNum, IsEH)) 81 if (const char *RegName = MCRegInfo->getName(*LLVMRegNum)) 82 return llvm::StringRef(RegName); 83 return {}; 84 }; 85 llvm::DIDumpOptions DumpOpts; 86 DumpOpts.GetNameForDWARFReg = GetRegName; 87 llvm::DWARFExpression(m_data.GetAsLLVM(), m_data.GetAddressByteSize()) 88 .print(s->AsRawOstream(), DumpOpts, nullptr); 89 } 90 91 RegisterKind DWARFExpression::GetRegisterKind() const { return m_reg_kind; } 92 93 void DWARFExpression::SetRegisterKind(RegisterKind reg_kind) { 94 m_reg_kind = reg_kind; 95 } 96 97 98 static bool ReadRegisterValueAsScalar(RegisterContext *reg_ctx, 99 lldb::RegisterKind reg_kind, 100 uint32_t reg_num, Status *error_ptr, 101 Value &value) { 102 if (reg_ctx == nullptr) { 103 if (error_ptr) 104 error_ptr->SetErrorString("No register context in frame.\n"); 105 } else { 106 uint32_t native_reg = 107 reg_ctx->ConvertRegisterKindToRegisterNumber(reg_kind, reg_num); 108 if (native_reg == LLDB_INVALID_REGNUM) { 109 if (error_ptr) 110 error_ptr->SetErrorStringWithFormat("Unable to convert register " 111 "kind=%u reg_num=%u to a native " 112 "register number.\n", 113 reg_kind, reg_num); 114 } else { 115 const RegisterInfo *reg_info = 116 reg_ctx->GetRegisterInfoAtIndex(native_reg); 117 RegisterValue reg_value; 118 if (reg_ctx->ReadRegister(reg_info, reg_value)) { 119 if (reg_value.GetScalarValue(value.GetScalar())) { 120 value.SetValueType(Value::ValueType::Scalar); 121 value.SetContext(Value::ContextType::RegisterInfo, 122 const_cast<RegisterInfo *>(reg_info)); 123 if (error_ptr) 124 error_ptr->Clear(); 125 return true; 126 } else { 127 // If we get this error, then we need to implement a value buffer in 128 // the dwarf expression evaluation function... 129 if (error_ptr) 130 error_ptr->SetErrorStringWithFormat( 131 "register %s can't be converted to a scalar value", 132 reg_info->name); 133 } 134 } else { 135 if (error_ptr) 136 error_ptr->SetErrorStringWithFormat("register %s is not available", 137 reg_info->name); 138 } 139 } 140 } 141 return false; 142 } 143 144 /// Return the length in bytes of the set of operands for \p op. No guarantees 145 /// are made on the state of \p data after this call. 146 static offset_t GetOpcodeDataSize(const DataExtractor &data, 147 const lldb::offset_t data_offset, 148 const uint8_t op, const DWARFUnit *dwarf_cu) { 149 lldb::offset_t offset = data_offset; 150 switch (op) { 151 case DW_OP_addr: 152 case DW_OP_call_ref: // 0x9a 1 address sized offset of DIE (DWARF3) 153 return data.GetAddressByteSize(); 154 155 // Opcodes with no arguments 156 case DW_OP_deref: // 0x06 157 case DW_OP_dup: // 0x12 158 case DW_OP_drop: // 0x13 159 case DW_OP_over: // 0x14 160 case DW_OP_swap: // 0x16 161 case DW_OP_rot: // 0x17 162 case DW_OP_xderef: // 0x18 163 case DW_OP_abs: // 0x19 164 case DW_OP_and: // 0x1a 165 case DW_OP_div: // 0x1b 166 case DW_OP_minus: // 0x1c 167 case DW_OP_mod: // 0x1d 168 case DW_OP_mul: // 0x1e 169 case DW_OP_neg: // 0x1f 170 case DW_OP_not: // 0x20 171 case DW_OP_or: // 0x21 172 case DW_OP_plus: // 0x22 173 case DW_OP_shl: // 0x24 174 case DW_OP_shr: // 0x25 175 case DW_OP_shra: // 0x26 176 case DW_OP_xor: // 0x27 177 case DW_OP_eq: // 0x29 178 case DW_OP_ge: // 0x2a 179 case DW_OP_gt: // 0x2b 180 case DW_OP_le: // 0x2c 181 case DW_OP_lt: // 0x2d 182 case DW_OP_ne: // 0x2e 183 case DW_OP_lit0: // 0x30 184 case DW_OP_lit1: // 0x31 185 case DW_OP_lit2: // 0x32 186 case DW_OP_lit3: // 0x33 187 case DW_OP_lit4: // 0x34 188 case DW_OP_lit5: // 0x35 189 case DW_OP_lit6: // 0x36 190 case DW_OP_lit7: // 0x37 191 case DW_OP_lit8: // 0x38 192 case DW_OP_lit9: // 0x39 193 case DW_OP_lit10: // 0x3A 194 case DW_OP_lit11: // 0x3B 195 case DW_OP_lit12: // 0x3C 196 case DW_OP_lit13: // 0x3D 197 case DW_OP_lit14: // 0x3E 198 case DW_OP_lit15: // 0x3F 199 case DW_OP_lit16: // 0x40 200 case DW_OP_lit17: // 0x41 201 case DW_OP_lit18: // 0x42 202 case DW_OP_lit19: // 0x43 203 case DW_OP_lit20: // 0x44 204 case DW_OP_lit21: // 0x45 205 case DW_OP_lit22: // 0x46 206 case DW_OP_lit23: // 0x47 207 case DW_OP_lit24: // 0x48 208 case DW_OP_lit25: // 0x49 209 case DW_OP_lit26: // 0x4A 210 case DW_OP_lit27: // 0x4B 211 case DW_OP_lit28: // 0x4C 212 case DW_OP_lit29: // 0x4D 213 case DW_OP_lit30: // 0x4E 214 case DW_OP_lit31: // 0x4f 215 case DW_OP_reg0: // 0x50 216 case DW_OP_reg1: // 0x51 217 case DW_OP_reg2: // 0x52 218 case DW_OP_reg3: // 0x53 219 case DW_OP_reg4: // 0x54 220 case DW_OP_reg5: // 0x55 221 case DW_OP_reg6: // 0x56 222 case DW_OP_reg7: // 0x57 223 case DW_OP_reg8: // 0x58 224 case DW_OP_reg9: // 0x59 225 case DW_OP_reg10: // 0x5A 226 case DW_OP_reg11: // 0x5B 227 case DW_OP_reg12: // 0x5C 228 case DW_OP_reg13: // 0x5D 229 case DW_OP_reg14: // 0x5E 230 case DW_OP_reg15: // 0x5F 231 case DW_OP_reg16: // 0x60 232 case DW_OP_reg17: // 0x61 233 case DW_OP_reg18: // 0x62 234 case DW_OP_reg19: // 0x63 235 case DW_OP_reg20: // 0x64 236 case DW_OP_reg21: // 0x65 237 case DW_OP_reg22: // 0x66 238 case DW_OP_reg23: // 0x67 239 case DW_OP_reg24: // 0x68 240 case DW_OP_reg25: // 0x69 241 case DW_OP_reg26: // 0x6A 242 case DW_OP_reg27: // 0x6B 243 case DW_OP_reg28: // 0x6C 244 case DW_OP_reg29: // 0x6D 245 case DW_OP_reg30: // 0x6E 246 case DW_OP_reg31: // 0x6F 247 case DW_OP_nop: // 0x96 248 case DW_OP_push_object_address: // 0x97 DWARF3 249 case DW_OP_form_tls_address: // 0x9b DWARF3 250 case DW_OP_call_frame_cfa: // 0x9c DWARF3 251 case DW_OP_stack_value: // 0x9f DWARF4 252 case DW_OP_GNU_push_tls_address: // 0xe0 GNU extension 253 return 0; 254 255 // Opcodes with a single 1 byte arguments 256 case DW_OP_const1u: // 0x08 1 1-byte constant 257 case DW_OP_const1s: // 0x09 1 1-byte constant 258 case DW_OP_pick: // 0x15 1 1-byte stack index 259 case DW_OP_deref_size: // 0x94 1 1-byte size of data retrieved 260 case DW_OP_xderef_size: // 0x95 1 1-byte size of data retrieved 261 return 1; 262 263 // Opcodes with a single 2 byte arguments 264 case DW_OP_const2u: // 0x0a 1 2-byte constant 265 case DW_OP_const2s: // 0x0b 1 2-byte constant 266 case DW_OP_skip: // 0x2f 1 signed 2-byte constant 267 case DW_OP_bra: // 0x28 1 signed 2-byte constant 268 case DW_OP_call2: // 0x98 1 2-byte offset of DIE (DWARF3) 269 return 2; 270 271 // Opcodes with a single 4 byte arguments 272 case DW_OP_const4u: // 0x0c 1 4-byte constant 273 case DW_OP_const4s: // 0x0d 1 4-byte constant 274 case DW_OP_call4: // 0x99 1 4-byte offset of DIE (DWARF3) 275 return 4; 276 277 // Opcodes with a single 8 byte arguments 278 case DW_OP_const8u: // 0x0e 1 8-byte constant 279 case DW_OP_const8s: // 0x0f 1 8-byte constant 280 return 8; 281 282 // All opcodes that have a single ULEB (signed or unsigned) argument 283 case DW_OP_addrx: // 0xa1 1 ULEB128 index 284 case DW_OP_constu: // 0x10 1 ULEB128 constant 285 case DW_OP_consts: // 0x11 1 SLEB128 constant 286 case DW_OP_plus_uconst: // 0x23 1 ULEB128 addend 287 case DW_OP_breg0: // 0x70 1 ULEB128 register 288 case DW_OP_breg1: // 0x71 1 ULEB128 register 289 case DW_OP_breg2: // 0x72 1 ULEB128 register 290 case DW_OP_breg3: // 0x73 1 ULEB128 register 291 case DW_OP_breg4: // 0x74 1 ULEB128 register 292 case DW_OP_breg5: // 0x75 1 ULEB128 register 293 case DW_OP_breg6: // 0x76 1 ULEB128 register 294 case DW_OP_breg7: // 0x77 1 ULEB128 register 295 case DW_OP_breg8: // 0x78 1 ULEB128 register 296 case DW_OP_breg9: // 0x79 1 ULEB128 register 297 case DW_OP_breg10: // 0x7a 1 ULEB128 register 298 case DW_OP_breg11: // 0x7b 1 ULEB128 register 299 case DW_OP_breg12: // 0x7c 1 ULEB128 register 300 case DW_OP_breg13: // 0x7d 1 ULEB128 register 301 case DW_OP_breg14: // 0x7e 1 ULEB128 register 302 case DW_OP_breg15: // 0x7f 1 ULEB128 register 303 case DW_OP_breg16: // 0x80 1 ULEB128 register 304 case DW_OP_breg17: // 0x81 1 ULEB128 register 305 case DW_OP_breg18: // 0x82 1 ULEB128 register 306 case DW_OP_breg19: // 0x83 1 ULEB128 register 307 case DW_OP_breg20: // 0x84 1 ULEB128 register 308 case DW_OP_breg21: // 0x85 1 ULEB128 register 309 case DW_OP_breg22: // 0x86 1 ULEB128 register 310 case DW_OP_breg23: // 0x87 1 ULEB128 register 311 case DW_OP_breg24: // 0x88 1 ULEB128 register 312 case DW_OP_breg25: // 0x89 1 ULEB128 register 313 case DW_OP_breg26: // 0x8a 1 ULEB128 register 314 case DW_OP_breg27: // 0x8b 1 ULEB128 register 315 case DW_OP_breg28: // 0x8c 1 ULEB128 register 316 case DW_OP_breg29: // 0x8d 1 ULEB128 register 317 case DW_OP_breg30: // 0x8e 1 ULEB128 register 318 case DW_OP_breg31: // 0x8f 1 ULEB128 register 319 case DW_OP_regx: // 0x90 1 ULEB128 register 320 case DW_OP_fbreg: // 0x91 1 SLEB128 offset 321 case DW_OP_piece: // 0x93 1 ULEB128 size of piece addressed 322 case DW_OP_GNU_addr_index: // 0xfb 1 ULEB128 index 323 case DW_OP_GNU_const_index: // 0xfc 1 ULEB128 index 324 data.Skip_LEB128(&offset); 325 return offset - data_offset; 326 327 // All opcodes that have a 2 ULEB (signed or unsigned) arguments 328 case DW_OP_bregx: // 0x92 2 ULEB128 register followed by SLEB128 offset 329 case DW_OP_bit_piece: // 0x9d ULEB128 bit size, ULEB128 bit offset (DWARF3); 330 data.Skip_LEB128(&offset); 331 data.Skip_LEB128(&offset); 332 return offset - data_offset; 333 334 case DW_OP_implicit_value: // 0x9e ULEB128 size followed by block of that size 335 // (DWARF4) 336 { 337 uint64_t block_len = data.Skip_LEB128(&offset); 338 offset += block_len; 339 return offset - data_offset; 340 } 341 342 case DW_OP_GNU_entry_value: 343 case DW_OP_entry_value: // 0xa3 ULEB128 size + variable-length block 344 { 345 uint64_t subexpr_len = data.GetULEB128(&offset); 346 return (offset - data_offset) + subexpr_len; 347 } 348 349 default: 350 if (!dwarf_cu) { 351 return LLDB_INVALID_OFFSET; 352 } 353 return dwarf_cu->GetSymbolFileDWARF().GetVendorDWARFOpcodeSize( 354 data, data_offset, op); 355 } 356 } 357 358 lldb::addr_t DWARFExpression::GetLocation_DW_OP_addr(const DWARFUnit *dwarf_cu, 359 bool &error) const { 360 error = false; 361 lldb::offset_t offset = 0; 362 while (m_data.ValidOffset(offset)) { 363 const uint8_t op = m_data.GetU8(&offset); 364 365 if (op == DW_OP_addr) 366 return m_data.GetAddress(&offset); 367 if (op == DW_OP_GNU_addr_index || op == DW_OP_addrx) { 368 uint64_t index = m_data.GetULEB128(&offset); 369 if (dwarf_cu) 370 return dwarf_cu->ReadAddressFromDebugAddrSection(index); 371 error = true; 372 break; 373 } 374 const offset_t op_arg_size = 375 GetOpcodeDataSize(m_data, offset, op, dwarf_cu); 376 if (op_arg_size == LLDB_INVALID_OFFSET) { 377 error = true; 378 break; 379 } 380 offset += op_arg_size; 381 } 382 return LLDB_INVALID_ADDRESS; 383 } 384 385 bool DWARFExpression::Update_DW_OP_addr(const DWARFUnit *dwarf_cu, 386 lldb::addr_t file_addr) { 387 lldb::offset_t offset = 0; 388 while (m_data.ValidOffset(offset)) { 389 const uint8_t op = m_data.GetU8(&offset); 390 391 if (op == DW_OP_addr) { 392 const uint32_t addr_byte_size = m_data.GetAddressByteSize(); 393 // We have to make a copy of the data as we don't know if this data is 394 // from a read only memory mapped buffer, so we duplicate all of the data 395 // first, then modify it, and if all goes well, we then replace the data 396 // for this expression 397 398 // Make en encoder that contains a copy of the location expression data 399 // so we can write the address into the buffer using the correct byte 400 // order. 401 DataEncoder encoder(m_data.GetDataStart(), m_data.GetByteSize(), 402 m_data.GetByteOrder(), addr_byte_size); 403 404 // Replace the address in the new buffer 405 if (encoder.PutAddress(offset, file_addr) == UINT32_MAX) 406 return false; 407 408 // All went well, so now we can reset the data using a shared pointer to 409 // the heap data so "m_data" will now correctly manage the heap data. 410 m_data.SetData(encoder.GetDataBuffer()); 411 return true; 412 } 413 if (op == DW_OP_addrx) { 414 // Replace DW_OP_addrx with DW_OP_addr, since we can't modify the 415 // read-only debug_addr table. 416 // Subtract one to account for the opcode. 417 llvm::ArrayRef data_before_op = m_data.GetData().take_front(offset - 1); 418 419 // Read the addrx index to determine how many bytes it needs. 420 const lldb::offset_t old_offset = offset; 421 m_data.GetULEB128(&offset); 422 if (old_offset == offset) 423 return false; 424 llvm::ArrayRef data_after_op = m_data.GetData().drop_front(offset); 425 426 DataEncoder encoder(m_data.GetByteOrder(), m_data.GetAddressByteSize()); 427 encoder.AppendData(data_before_op); 428 encoder.AppendU8(DW_OP_addr); 429 encoder.AppendAddress(file_addr); 430 encoder.AppendData(data_after_op); 431 m_data.SetData(encoder.GetDataBuffer()); 432 return true; 433 } 434 const offset_t op_arg_size = 435 GetOpcodeDataSize(m_data, offset, op, dwarf_cu); 436 if (op_arg_size == LLDB_INVALID_OFFSET) 437 break; 438 offset += op_arg_size; 439 } 440 return false; 441 } 442 443 bool DWARFExpression::ContainsThreadLocalStorage( 444 const DWARFUnit *dwarf_cu) const { 445 lldb::offset_t offset = 0; 446 while (m_data.ValidOffset(offset)) { 447 const uint8_t op = m_data.GetU8(&offset); 448 449 if (op == DW_OP_form_tls_address || op == DW_OP_GNU_push_tls_address) 450 return true; 451 const offset_t op_arg_size = 452 GetOpcodeDataSize(m_data, offset, op, dwarf_cu); 453 if (op_arg_size == LLDB_INVALID_OFFSET) 454 return false; 455 offset += op_arg_size; 456 } 457 return false; 458 } 459 bool DWARFExpression::LinkThreadLocalStorage( 460 const DWARFUnit *dwarf_cu, 461 std::function<lldb::addr_t(lldb::addr_t file_addr)> const 462 &link_address_callback) { 463 const uint32_t addr_byte_size = m_data.GetAddressByteSize(); 464 // We have to make a copy of the data as we don't know if this data is from a 465 // read only memory mapped buffer, so we duplicate all of the data first, 466 // then modify it, and if all goes well, we then replace the data for this 467 // expression. 468 // Make en encoder that contains a copy of the location expression data so we 469 // can write the address into the buffer using the correct byte order. 470 DataEncoder encoder(m_data.GetDataStart(), m_data.GetByteSize(), 471 m_data.GetByteOrder(), addr_byte_size); 472 473 lldb::offset_t offset = 0; 474 lldb::offset_t const_offset = 0; 475 lldb::addr_t const_value = 0; 476 size_t const_byte_size = 0; 477 while (m_data.ValidOffset(offset)) { 478 const uint8_t op = m_data.GetU8(&offset); 479 480 bool decoded_data = false; 481 switch (op) { 482 case DW_OP_const4u: 483 // Remember the const offset in case we later have a 484 // DW_OP_form_tls_address or DW_OP_GNU_push_tls_address 485 const_offset = offset; 486 const_value = m_data.GetU32(&offset); 487 decoded_data = true; 488 const_byte_size = 4; 489 break; 490 491 case DW_OP_const8u: 492 // Remember the const offset in case we later have a 493 // DW_OP_form_tls_address or DW_OP_GNU_push_tls_address 494 const_offset = offset; 495 const_value = m_data.GetU64(&offset); 496 decoded_data = true; 497 const_byte_size = 8; 498 break; 499 500 case DW_OP_form_tls_address: 501 case DW_OP_GNU_push_tls_address: 502 // DW_OP_form_tls_address and DW_OP_GNU_push_tls_address must be preceded 503 // by a file address on the stack. We assume that DW_OP_const4u or 504 // DW_OP_const8u is used for these values, and we check that the last 505 // opcode we got before either of these was DW_OP_const4u or 506 // DW_OP_const8u. If so, then we can link the value accordingly. For 507 // Darwin, the value in the DW_OP_const4u or DW_OP_const8u is the file 508 // address of a structure that contains a function pointer, the pthread 509 // key and the offset into the data pointed to by the pthread key. So we 510 // must link this address and also set the module of this expression to 511 // the new_module_sp so we can resolve the file address correctly 512 if (const_byte_size > 0) { 513 lldb::addr_t linked_file_addr = link_address_callback(const_value); 514 if (linked_file_addr == LLDB_INVALID_ADDRESS) 515 return false; 516 // Replace the address in the new buffer 517 if (encoder.PutUnsigned(const_offset, const_byte_size, 518 linked_file_addr) == UINT32_MAX) 519 return false; 520 } 521 break; 522 523 default: 524 const_offset = 0; 525 const_value = 0; 526 const_byte_size = 0; 527 break; 528 } 529 530 if (!decoded_data) { 531 const offset_t op_arg_size = 532 GetOpcodeDataSize(m_data, offset, op, dwarf_cu); 533 if (op_arg_size == LLDB_INVALID_OFFSET) 534 return false; 535 else 536 offset += op_arg_size; 537 } 538 } 539 540 m_data.SetData(encoder.GetDataBuffer()); 541 return true; 542 } 543 544 static bool Evaluate_DW_OP_entry_value(std::vector<Value> &stack, 545 ExecutionContext *exe_ctx, 546 RegisterContext *reg_ctx, 547 const DataExtractor &opcodes, 548 lldb::offset_t &opcode_offset, 549 Status *error_ptr, Log *log) { 550 // DW_OP_entry_value(sub-expr) describes the location a variable had upon 551 // function entry: this variable location is presumed to be optimized out at 552 // the current PC value. The caller of the function may have call site 553 // information that describes an alternate location for the variable (e.g. a 554 // constant literal, or a spilled stack value) in the parent frame. 555 // 556 // Example (this is pseudo-code & pseudo-DWARF, but hopefully illustrative): 557 // 558 // void child(int &sink, int x) { 559 // ... 560 // /* "x" gets optimized out. */ 561 // 562 // /* The location of "x" here is: DW_OP_entry_value($reg2). */ 563 // ++sink; 564 // } 565 // 566 // void parent() { 567 // int sink; 568 // 569 // /* 570 // * The callsite information emitted here is: 571 // * 572 // * DW_TAG_call_site 573 // * DW_AT_return_pc ... (for "child(sink, 123);") 574 // * DW_TAG_call_site_parameter (for "sink") 575 // * DW_AT_location ($reg1) 576 // * DW_AT_call_value ($SP - 8) 577 // * DW_TAG_call_site_parameter (for "x") 578 // * DW_AT_location ($reg2) 579 // * DW_AT_call_value ($literal 123) 580 // * 581 // * DW_TAG_call_site 582 // * DW_AT_return_pc ... (for "child(sink, 456);") 583 // * ... 584 // */ 585 // child(sink, 123); 586 // child(sink, 456); 587 // } 588 // 589 // When the program stops at "++sink" within `child`, the debugger determines 590 // the call site by analyzing the return address. Once the call site is found, 591 // the debugger determines which parameter is referenced by DW_OP_entry_value 592 // and evaluates the corresponding location for that parameter in `parent`. 593 594 // 1. Find the function which pushed the current frame onto the stack. 595 if ((!exe_ctx || !exe_ctx->HasTargetScope()) || !reg_ctx) { 596 LLDB_LOG(log, "Evaluate_DW_OP_entry_value: no exe/reg context"); 597 return false; 598 } 599 600 StackFrame *current_frame = exe_ctx->GetFramePtr(); 601 Thread *thread = exe_ctx->GetThreadPtr(); 602 if (!current_frame || !thread) { 603 LLDB_LOG(log, "Evaluate_DW_OP_entry_value: no current frame/thread"); 604 return false; 605 } 606 607 Target &target = exe_ctx->GetTargetRef(); 608 StackFrameSP parent_frame = nullptr; 609 addr_t return_pc = LLDB_INVALID_ADDRESS; 610 uint32_t current_frame_idx = current_frame->GetFrameIndex(); 611 uint32_t num_frames = thread->GetStackFrameCount(); 612 for (uint32_t parent_frame_idx = current_frame_idx + 1; 613 parent_frame_idx < num_frames; ++parent_frame_idx) { 614 parent_frame = thread->GetStackFrameAtIndex(parent_frame_idx); 615 // Require a valid sequence of frames. 616 if (!parent_frame) 617 break; 618 619 // Record the first valid return address, even if this is an inlined frame, 620 // in order to look up the associated call edge in the first non-inlined 621 // parent frame. 622 if (return_pc == LLDB_INVALID_ADDRESS) { 623 return_pc = parent_frame->GetFrameCodeAddress().GetLoadAddress(&target); 624 LLDB_LOG(log, 625 "Evaluate_DW_OP_entry_value: immediate ancestor with pc = {0:x}", 626 return_pc); 627 } 628 629 // If we've found an inlined frame, skip it (these have no call site 630 // parameters). 631 if (parent_frame->IsInlined()) 632 continue; 633 634 // We've found the first non-inlined parent frame. 635 break; 636 } 637 if (!parent_frame || !parent_frame->GetRegisterContext()) { 638 LLDB_LOG(log, "Evaluate_DW_OP_entry_value: no parent frame with reg ctx"); 639 return false; 640 } 641 642 Function *parent_func = 643 parent_frame->GetSymbolContext(eSymbolContextFunction).function; 644 if (!parent_func) { 645 LLDB_LOG(log, "Evaluate_DW_OP_entry_value: no parent function"); 646 return false; 647 } 648 649 // 2. Find the call edge in the parent function responsible for creating the 650 // current activation. 651 Function *current_func = 652 current_frame->GetSymbolContext(eSymbolContextFunction).function; 653 if (!current_func) { 654 LLDB_LOG(log, "Evaluate_DW_OP_entry_value: no current function"); 655 return false; 656 } 657 658 CallEdge *call_edge = nullptr; 659 ModuleList &modlist = target.GetImages(); 660 ExecutionContext parent_exe_ctx = *exe_ctx; 661 parent_exe_ctx.SetFrameSP(parent_frame); 662 if (!parent_frame->IsArtificial()) { 663 // If the parent frame is not artificial, the current activation may be 664 // produced by an ambiguous tail call. In this case, refuse to proceed. 665 call_edge = parent_func->GetCallEdgeForReturnAddress(return_pc, target); 666 if (!call_edge) { 667 LLDB_LOG(log, 668 "Evaluate_DW_OP_entry_value: no call edge for retn-pc = {0:x} " 669 "in parent frame {1}", 670 return_pc, parent_func->GetName()); 671 return false; 672 } 673 Function *callee_func = call_edge->GetCallee(modlist, parent_exe_ctx); 674 if (callee_func != current_func) { 675 LLDB_LOG(log, "Evaluate_DW_OP_entry_value: ambiguous call sequence, " 676 "can't find real parent frame"); 677 return false; 678 } 679 } else { 680 // The StackFrameList solver machinery has deduced that an unambiguous tail 681 // call sequence that produced the current activation. The first edge in 682 // the parent that points to the current function must be valid. 683 for (auto &edge : parent_func->GetTailCallingEdges()) { 684 if (edge->GetCallee(modlist, parent_exe_ctx) == current_func) { 685 call_edge = edge.get(); 686 break; 687 } 688 } 689 } 690 if (!call_edge) { 691 LLDB_LOG(log, "Evaluate_DW_OP_entry_value: no unambiguous edge from parent " 692 "to current function"); 693 return false; 694 } 695 696 // 3. Attempt to locate the DW_OP_entry_value expression in the set of 697 // available call site parameters. If found, evaluate the corresponding 698 // parameter in the context of the parent frame. 699 const uint32_t subexpr_len = opcodes.GetULEB128(&opcode_offset); 700 const void *subexpr_data = opcodes.GetData(&opcode_offset, subexpr_len); 701 if (!subexpr_data) { 702 LLDB_LOG(log, "Evaluate_DW_OP_entry_value: subexpr could not be read"); 703 return false; 704 } 705 706 const CallSiteParameter *matched_param = nullptr; 707 for (const CallSiteParameter ¶m : call_edge->GetCallSiteParameters()) { 708 DataExtractor param_subexpr_extractor; 709 if (!param.LocationInCallee.GetExpressionData(param_subexpr_extractor)) 710 continue; 711 lldb::offset_t param_subexpr_offset = 0; 712 const void *param_subexpr_data = 713 param_subexpr_extractor.GetData(¶m_subexpr_offset, subexpr_len); 714 if (!param_subexpr_data || 715 param_subexpr_extractor.BytesLeft(param_subexpr_offset) != 0) 716 continue; 717 718 // At this point, the DW_OP_entry_value sub-expression and the callee-side 719 // expression in the call site parameter are known to have the same length. 720 // Check whether they are equal. 721 // 722 // Note that an equality check is sufficient: the contents of the 723 // DW_OP_entry_value subexpression are only used to identify the right call 724 // site parameter in the parent, and do not require any special handling. 725 if (memcmp(subexpr_data, param_subexpr_data, subexpr_len) == 0) { 726 matched_param = ¶m; 727 break; 728 } 729 } 730 if (!matched_param) { 731 LLDB_LOG(log, 732 "Evaluate_DW_OP_entry_value: no matching call site param found"); 733 return false; 734 } 735 736 // TODO: Add support for DW_OP_push_object_address within a DW_OP_entry_value 737 // subexpresion whenever llvm does. 738 Value result; 739 const DWARFExpressionList ¶m_expr = matched_param->LocationInCaller; 740 if (!param_expr.Evaluate(&parent_exe_ctx, 741 parent_frame->GetRegisterContext().get(), 742 LLDB_INVALID_ADDRESS, 743 /*initial_value_ptr=*/nullptr, 744 /*object_address_ptr=*/nullptr, result, error_ptr)) { 745 LLDB_LOG(log, 746 "Evaluate_DW_OP_entry_value: call site param evaluation failed"); 747 return false; 748 } 749 750 stack.push_back(result); 751 return true; 752 } 753 754 namespace { 755 /// The location description kinds described by the DWARF v5 756 /// specification. Composite locations are handled out-of-band and 757 /// thus aren't part of the enum. 758 enum LocationDescriptionKind { 759 Empty, 760 Memory, 761 Register, 762 Implicit 763 /* Composite*/ 764 }; 765 /// Adjust value's ValueType according to the kind of location description. 766 void UpdateValueTypeFromLocationDescription(Log *log, const DWARFUnit *dwarf_cu, 767 LocationDescriptionKind kind, 768 Value *value = nullptr) { 769 // Note that this function is conflating DWARF expressions with 770 // DWARF location descriptions. Perhaps it would be better to define 771 // a wrapper for DWARFExpression::Eval() that deals with DWARF 772 // location descriptions (which consist of one or more DWARF 773 // expressions). But doing this would mean we'd also need factor the 774 // handling of DW_OP_(bit_)piece out of this function. 775 if (dwarf_cu && dwarf_cu->GetVersion() >= 4) { 776 const char *log_msg = "DWARF location description kind: %s"; 777 switch (kind) { 778 case Empty: 779 LLDB_LOGF(log, log_msg, "Empty"); 780 break; 781 case Memory: 782 LLDB_LOGF(log, log_msg, "Memory"); 783 if (value->GetValueType() == Value::ValueType::Scalar) 784 value->SetValueType(Value::ValueType::LoadAddress); 785 break; 786 case Register: 787 LLDB_LOGF(log, log_msg, "Register"); 788 value->SetValueType(Value::ValueType::Scalar); 789 break; 790 case Implicit: 791 LLDB_LOGF(log, log_msg, "Implicit"); 792 if (value->GetValueType() == Value::ValueType::LoadAddress) 793 value->SetValueType(Value::ValueType::Scalar); 794 break; 795 } 796 } 797 } 798 } // namespace 799 800 /// Helper function to move common code used to resolve a file address and turn 801 /// into a load address. 802 /// 803 /// \param exe_ctx Pointer to the execution context 804 /// \param module_sp shared_ptr contains the module if we have one 805 /// \param error_ptr pointer to Status object if we have one 806 /// \param dw_op_type C-style string used to vary the error output 807 /// \param file_addr the file address we are trying to resolve and turn into a 808 /// load address 809 /// \param so_addr out parameter, will be set to load address or section offset 810 /// \param check_sectionoffset bool which determines if having a section offset 811 /// but not a load address is considerd a success 812 /// \returns std::optional containing the load address if resolving and getting 813 /// the load address succeed or an empty Optinal otherwise. If 814 /// check_sectionoffset is true we consider LLDB_INVALID_ADDRESS a 815 /// success if so_addr.IsSectionOffset() is true. 816 static std::optional<lldb::addr_t> 817 ResolveLoadAddress(ExecutionContext *exe_ctx, lldb::ModuleSP &module_sp, 818 Status *error_ptr, const char *dw_op_type, 819 lldb::addr_t file_addr, Address &so_addr, 820 bool check_sectionoffset = false) { 821 if (!module_sp) { 822 if (error_ptr) 823 error_ptr->SetErrorStringWithFormat( 824 "need module to resolve file address for %s", dw_op_type); 825 return {}; 826 } 827 828 if (!module_sp->ResolveFileAddress(file_addr, so_addr)) { 829 if (error_ptr) 830 error_ptr->SetErrorString("failed to resolve file address in module"); 831 return {}; 832 } 833 834 addr_t load_addr = so_addr.GetLoadAddress(exe_ctx->GetTargetPtr()); 835 836 if (load_addr == LLDB_INVALID_ADDRESS && 837 (check_sectionoffset && !so_addr.IsSectionOffset())) { 838 if (error_ptr) 839 error_ptr->SetErrorString("failed to resolve load address"); 840 return {}; 841 } 842 843 return load_addr; 844 } 845 846 /// Helper function to move common code used to load sized data from a uint8_t 847 /// buffer. 848 /// 849 /// \param addr_bytes uint8_t buffer containg raw data 850 /// \param size_addr_bytes how large is the underlying raw data 851 /// \param byte_order what is the byter order of the underlyig data 852 /// \param size How much of the underlying data we want to use 853 /// \return The underlying data converted into a Scalar 854 static Scalar DerefSizeExtractDataHelper(uint8_t *addr_bytes, 855 size_t size_addr_bytes, 856 ByteOrder byte_order, size_t size) { 857 DataExtractor addr_data(addr_bytes, size_addr_bytes, byte_order, size); 858 859 lldb::offset_t addr_data_offset = 0; 860 if (size <= 8) 861 return addr_data.GetMaxU64(&addr_data_offset, size); 862 else 863 return addr_data.GetAddress(&addr_data_offset); 864 } 865 866 bool DWARFExpression::Evaluate( 867 ExecutionContext *exe_ctx, RegisterContext *reg_ctx, 868 lldb::ModuleSP module_sp, const DataExtractor &opcodes, 869 const DWARFUnit *dwarf_cu, const lldb::RegisterKind reg_kind, 870 const Value *initial_value_ptr, const Value *object_address_ptr, 871 Value &result, Status *error_ptr) { 872 873 if (opcodes.GetByteSize() == 0) { 874 if (error_ptr) 875 error_ptr->SetErrorString( 876 "no location, value may have been optimized out"); 877 return false; 878 } 879 std::vector<Value> stack; 880 881 Process *process = nullptr; 882 StackFrame *frame = nullptr; 883 Target *target = nullptr; 884 885 if (exe_ctx) { 886 process = exe_ctx->GetProcessPtr(); 887 frame = exe_ctx->GetFramePtr(); 888 target = exe_ctx->GetTargetPtr(); 889 } 890 if (reg_ctx == nullptr && frame) 891 reg_ctx = frame->GetRegisterContext().get(); 892 893 if (initial_value_ptr) 894 stack.push_back(*initial_value_ptr); 895 896 lldb::offset_t offset = 0; 897 Value tmp; 898 uint32_t reg_num; 899 900 /// Insertion point for evaluating multi-piece expression. 901 uint64_t op_piece_offset = 0; 902 Value pieces; // Used for DW_OP_piece 903 904 Log *log = GetLog(LLDBLog::Expressions); 905 // A generic type is "an integral type that has the size of an address and an 906 // unspecified signedness". For now, just use the signedness of the operand. 907 // TODO: Implement a real typed stack, and store the genericness of the value 908 // there. 909 auto to_generic = [&](auto v) { 910 bool is_signed = std::is_signed<decltype(v)>::value; 911 return Scalar(llvm::APSInt( 912 llvm::APInt(8 * opcodes.GetAddressByteSize(), v, is_signed), 913 !is_signed)); 914 }; 915 916 // The default kind is a memory location. This is updated by any 917 // operation that changes this, such as DW_OP_stack_value, and reset 918 // by composition operations like DW_OP_piece. 919 LocationDescriptionKind dwarf4_location_description_kind = Memory; 920 921 while (opcodes.ValidOffset(offset)) { 922 const lldb::offset_t op_offset = offset; 923 const uint8_t op = opcodes.GetU8(&offset); 924 925 if (log && log->GetVerbose()) { 926 size_t count = stack.size(); 927 LLDB_LOGF(log, "Stack before operation has %" PRIu64 " values:", 928 (uint64_t)count); 929 for (size_t i = 0; i < count; ++i) { 930 StreamString new_value; 931 new_value.Printf("[%" PRIu64 "]", (uint64_t)i); 932 stack[i].Dump(&new_value); 933 LLDB_LOGF(log, " %s", new_value.GetData()); 934 } 935 LLDB_LOGF(log, "0x%8.8" PRIx64 ": %s", op_offset, 936 DW_OP_value_to_name(op)); 937 } 938 939 switch (op) { 940 // The DW_OP_addr operation has a single operand that encodes a machine 941 // address and whose size is the size of an address on the target machine. 942 case DW_OP_addr: 943 stack.push_back(Scalar(opcodes.GetAddress(&offset))); 944 if (target && 945 target->GetArchitecture().GetCore() == ArchSpec::eCore_wasm32) { 946 // wasm file sections aren't mapped into memory, therefore addresses can 947 // never point into a file section and are always LoadAddresses. 948 stack.back().SetValueType(Value::ValueType::LoadAddress); 949 } else { 950 stack.back().SetValueType(Value::ValueType::FileAddress); 951 } 952 break; 953 954 // The DW_OP_addr_sect_offset4 is used for any location expressions in 955 // shared libraries that have a location like: 956 // DW_OP_addr(0x1000) 957 // If this address resides in a shared library, then this virtual address 958 // won't make sense when it is evaluated in the context of a running 959 // process where shared libraries have been slid. To account for this, this 960 // new address type where we can store the section pointer and a 4 byte 961 // offset. 962 // case DW_OP_addr_sect_offset4: 963 // { 964 // result_type = eResultTypeFileAddress; 965 // lldb::Section *sect = (lldb::Section 966 // *)opcodes.GetMaxU64(&offset, sizeof(void *)); 967 // lldb::addr_t sect_offset = opcodes.GetU32(&offset); 968 // 969 // Address so_addr (sect, sect_offset); 970 // lldb::addr_t load_addr = so_addr.GetLoadAddress(); 971 // if (load_addr != LLDB_INVALID_ADDRESS) 972 // { 973 // // We successfully resolve a file address to a load 974 // // address. 975 // stack.push_back(load_addr); 976 // break; 977 // } 978 // else 979 // { 980 // // We were able 981 // if (error_ptr) 982 // error_ptr->SetErrorStringWithFormat ("Section %s in 983 // %s is not currently loaded.\n", 984 // sect->GetName().AsCString(), 985 // sect->GetModule()->GetFileSpec().GetFilename().AsCString()); 986 // return false; 987 // } 988 // } 989 // break; 990 991 // OPCODE: DW_OP_deref 992 // OPERANDS: none 993 // DESCRIPTION: Pops the top stack entry and treats it as an address. 994 // The value retrieved from that address is pushed. The size of the data 995 // retrieved from the dereferenced address is the size of an address on the 996 // target machine. 997 case DW_OP_deref: { 998 if (stack.empty()) { 999 if (error_ptr) 1000 error_ptr->SetErrorString("Expression stack empty for DW_OP_deref."); 1001 return false; 1002 } 1003 Value::ValueType value_type = stack.back().GetValueType(); 1004 switch (value_type) { 1005 case Value::ValueType::HostAddress: { 1006 void *src = (void *)stack.back().GetScalar().ULongLong(); 1007 intptr_t ptr; 1008 ::memcpy(&ptr, src, sizeof(void *)); 1009 stack.back().GetScalar() = ptr; 1010 stack.back().ClearContext(); 1011 } break; 1012 case Value::ValueType::FileAddress: { 1013 auto file_addr = stack.back().GetScalar().ULongLong( 1014 LLDB_INVALID_ADDRESS); 1015 1016 Address so_addr; 1017 auto maybe_load_addr = ResolveLoadAddress( 1018 exe_ctx, module_sp, error_ptr, "DW_OP_deref", file_addr, so_addr); 1019 1020 if (!maybe_load_addr) 1021 return false; 1022 1023 stack.back().GetScalar() = *maybe_load_addr; 1024 // Fall through to load address promotion code below. 1025 } 1026 [[fallthrough]]; 1027 case Value::ValueType::Scalar: 1028 // Promote Scalar to LoadAddress and fall through. 1029 stack.back().SetValueType(Value::ValueType::LoadAddress); 1030 [[fallthrough]]; 1031 case Value::ValueType::LoadAddress: 1032 if (exe_ctx) { 1033 if (process) { 1034 lldb::addr_t pointer_addr = 1035 stack.back().GetScalar().ULongLong(LLDB_INVALID_ADDRESS); 1036 Status error; 1037 lldb::addr_t pointer_value = 1038 process->ReadPointerFromMemory(pointer_addr, error); 1039 if (pointer_value != LLDB_INVALID_ADDRESS) { 1040 if (ABISP abi_sp = process->GetABI()) 1041 pointer_value = abi_sp->FixCodeAddress(pointer_value); 1042 stack.back().GetScalar() = pointer_value; 1043 stack.back().ClearContext(); 1044 } else { 1045 if (error_ptr) 1046 error_ptr->SetErrorStringWithFormat( 1047 "Failed to dereference pointer from 0x%" PRIx64 1048 " for DW_OP_deref: %s\n", 1049 pointer_addr, error.AsCString()); 1050 return false; 1051 } 1052 } else { 1053 if (error_ptr) 1054 error_ptr->SetErrorString("NULL process for DW_OP_deref.\n"); 1055 return false; 1056 } 1057 } else { 1058 if (error_ptr) 1059 error_ptr->SetErrorString( 1060 "NULL execution context for DW_OP_deref.\n"); 1061 return false; 1062 } 1063 break; 1064 1065 case Value::ValueType::Invalid: 1066 if (error_ptr) 1067 error_ptr->SetErrorString("Invalid value type for DW_OP_deref.\n"); 1068 return false; 1069 } 1070 1071 } break; 1072 1073 // OPCODE: DW_OP_deref_size 1074 // OPERANDS: 1 1075 // 1 - uint8_t that specifies the size of the data to dereference. 1076 // DESCRIPTION: Behaves like the DW_OP_deref operation: it pops the top 1077 // stack entry and treats it as an address. The value retrieved from that 1078 // address is pushed. In the DW_OP_deref_size operation, however, the size 1079 // in bytes of the data retrieved from the dereferenced address is 1080 // specified by the single operand. This operand is a 1-byte unsigned 1081 // integral constant whose value may not be larger than the size of an 1082 // address on the target machine. The data retrieved is zero extended to 1083 // the size of an address on the target machine before being pushed on the 1084 // expression stack. 1085 case DW_OP_deref_size: { 1086 if (stack.empty()) { 1087 if (error_ptr) 1088 error_ptr->SetErrorString( 1089 "Expression stack empty for DW_OP_deref_size."); 1090 return false; 1091 } 1092 uint8_t size = opcodes.GetU8(&offset); 1093 if (size > 8) { 1094 if (error_ptr) 1095 error_ptr->SetErrorStringWithFormat( 1096 "Invalid address size for DW_OP_deref_size: %d\n", 1097 size); 1098 return false; 1099 } 1100 Value::ValueType value_type = stack.back().GetValueType(); 1101 switch (value_type) { 1102 case Value::ValueType::HostAddress: { 1103 void *src = (void *)stack.back().GetScalar().ULongLong(); 1104 intptr_t ptr; 1105 ::memcpy(&ptr, src, sizeof(void *)); 1106 // I can't decide whether the size operand should apply to the bytes in 1107 // their 1108 // lldb-host endianness or the target endianness.. I doubt this'll ever 1109 // come up but I'll opt for assuming big endian regardless. 1110 switch (size) { 1111 case 1: 1112 ptr = ptr & 0xff; 1113 break; 1114 case 2: 1115 ptr = ptr & 0xffff; 1116 break; 1117 case 3: 1118 ptr = ptr & 0xffffff; 1119 break; 1120 case 4: 1121 ptr = ptr & 0xffffffff; 1122 break; 1123 // the casts are added to work around the case where intptr_t is a 32 1124 // bit quantity; 1125 // presumably we won't hit the 5..7 cases if (void*) is 32-bits in this 1126 // program. 1127 case 5: 1128 ptr = (intptr_t)ptr & 0xffffffffffULL; 1129 break; 1130 case 6: 1131 ptr = (intptr_t)ptr & 0xffffffffffffULL; 1132 break; 1133 case 7: 1134 ptr = (intptr_t)ptr & 0xffffffffffffffULL; 1135 break; 1136 default: 1137 break; 1138 } 1139 stack.back().GetScalar() = ptr; 1140 stack.back().ClearContext(); 1141 } break; 1142 case Value::ValueType::FileAddress: { 1143 auto file_addr = 1144 stack.back().GetScalar().ULongLong(LLDB_INVALID_ADDRESS); 1145 Address so_addr; 1146 auto maybe_load_addr = 1147 ResolveLoadAddress(exe_ctx, module_sp, error_ptr, 1148 "DW_OP_deref_size", file_addr, so_addr, 1149 /*check_sectionoffset=*/true); 1150 1151 if (!maybe_load_addr) 1152 return false; 1153 1154 addr_t load_addr = *maybe_load_addr; 1155 1156 if (load_addr == LLDB_INVALID_ADDRESS && so_addr.IsSectionOffset()) { 1157 uint8_t addr_bytes[8]; 1158 Status error; 1159 1160 if (target && 1161 target->ReadMemory(so_addr, &addr_bytes, size, error, 1162 /*force_live_memory=*/false) == size) { 1163 ObjectFile *objfile = module_sp->GetObjectFile(); 1164 1165 stack.back().GetScalar() = DerefSizeExtractDataHelper( 1166 addr_bytes, size, objfile->GetByteOrder(), size); 1167 stack.back().ClearContext(); 1168 break; 1169 } else { 1170 if (error_ptr) 1171 error_ptr->SetErrorStringWithFormat( 1172 "Failed to dereference pointer for DW_OP_deref_size: " 1173 "%s\n", 1174 error.AsCString()); 1175 return false; 1176 } 1177 } 1178 stack.back().GetScalar() = load_addr; 1179 // Fall through to load address promotion code below. 1180 } 1181 1182 [[fallthrough]]; 1183 case Value::ValueType::Scalar: 1184 case Value::ValueType::LoadAddress: 1185 if (exe_ctx) { 1186 if (process) { 1187 lldb::addr_t pointer_addr = 1188 stack.back().GetScalar().ULongLong(LLDB_INVALID_ADDRESS); 1189 uint8_t addr_bytes[sizeof(lldb::addr_t)]; 1190 Status error; 1191 if (process->ReadMemory(pointer_addr, &addr_bytes, size, error) == 1192 size) { 1193 1194 stack.back().GetScalar() = 1195 DerefSizeExtractDataHelper(addr_bytes, sizeof(addr_bytes), 1196 process->GetByteOrder(), size); 1197 stack.back().ClearContext(); 1198 } else { 1199 if (error_ptr) 1200 error_ptr->SetErrorStringWithFormat( 1201 "Failed to dereference pointer from 0x%" PRIx64 1202 " for DW_OP_deref: %s\n", 1203 pointer_addr, error.AsCString()); 1204 return false; 1205 } 1206 } else { 1207 if (error_ptr) 1208 error_ptr->SetErrorString("NULL process for DW_OP_deref_size.\n"); 1209 return false; 1210 } 1211 } else { 1212 if (error_ptr) 1213 error_ptr->SetErrorString( 1214 "NULL execution context for DW_OP_deref_size.\n"); 1215 return false; 1216 } 1217 break; 1218 1219 case Value::ValueType::Invalid: 1220 if (error_ptr) 1221 error_ptr->SetErrorString("Invalid value for DW_OP_deref_size.\n"); 1222 return false; 1223 } 1224 1225 } break; 1226 1227 // OPCODE: DW_OP_xderef_size 1228 // OPERANDS: 1 1229 // 1 - uint8_t that specifies the size of the data to dereference. 1230 // DESCRIPTION: Behaves like the DW_OP_xderef operation: the entry at 1231 // the top of the stack is treated as an address. The second stack entry is 1232 // treated as an "address space identifier" for those architectures that 1233 // support multiple address spaces. The top two stack elements are popped, 1234 // a data item is retrieved through an implementation-defined address 1235 // calculation and pushed as the new stack top. In the DW_OP_xderef_size 1236 // operation, however, the size in bytes of the data retrieved from the 1237 // dereferenced address is specified by the single operand. This operand is 1238 // a 1-byte unsigned integral constant whose value may not be larger than 1239 // the size of an address on the target machine. The data retrieved is zero 1240 // extended to the size of an address on the target machine before being 1241 // pushed on the expression stack. 1242 case DW_OP_xderef_size: 1243 if (error_ptr) 1244 error_ptr->SetErrorString("Unimplemented opcode: DW_OP_xderef_size."); 1245 return false; 1246 // OPCODE: DW_OP_xderef 1247 // OPERANDS: none 1248 // DESCRIPTION: Provides an extended dereference mechanism. The entry at 1249 // the top of the stack is treated as an address. The second stack entry is 1250 // treated as an "address space identifier" for those architectures that 1251 // support multiple address spaces. The top two stack elements are popped, 1252 // a data item is retrieved through an implementation-defined address 1253 // calculation and pushed as the new stack top. The size of the data 1254 // retrieved from the dereferenced address is the size of an address on the 1255 // target machine. 1256 case DW_OP_xderef: 1257 if (error_ptr) 1258 error_ptr->SetErrorString("Unimplemented opcode: DW_OP_xderef."); 1259 return false; 1260 1261 // All DW_OP_constXXX opcodes have a single operand as noted below: 1262 // 1263 // Opcode Operand 1 1264 // DW_OP_const1u 1-byte unsigned integer constant 1265 // DW_OP_const1s 1-byte signed integer constant 1266 // DW_OP_const2u 2-byte unsigned integer constant 1267 // DW_OP_const2s 2-byte signed integer constant 1268 // DW_OP_const4u 4-byte unsigned integer constant 1269 // DW_OP_const4s 4-byte signed integer constant 1270 // DW_OP_const8u 8-byte unsigned integer constant 1271 // DW_OP_const8s 8-byte signed integer constant 1272 // DW_OP_constu unsigned LEB128 integer constant 1273 // DW_OP_consts signed LEB128 integer constant 1274 case DW_OP_const1u: 1275 stack.push_back(to_generic(opcodes.GetU8(&offset))); 1276 break; 1277 case DW_OP_const1s: 1278 stack.push_back(to_generic((int8_t)opcodes.GetU8(&offset))); 1279 break; 1280 case DW_OP_const2u: 1281 stack.push_back(to_generic(opcodes.GetU16(&offset))); 1282 break; 1283 case DW_OP_const2s: 1284 stack.push_back(to_generic((int16_t)opcodes.GetU16(&offset))); 1285 break; 1286 case DW_OP_const4u: 1287 stack.push_back(to_generic(opcodes.GetU32(&offset))); 1288 break; 1289 case DW_OP_const4s: 1290 stack.push_back(to_generic((int32_t)opcodes.GetU32(&offset))); 1291 break; 1292 case DW_OP_const8u: 1293 stack.push_back(to_generic(opcodes.GetU64(&offset))); 1294 break; 1295 case DW_OP_const8s: 1296 stack.push_back(to_generic((int64_t)opcodes.GetU64(&offset))); 1297 break; 1298 // These should also use to_generic, but we can't do that due to a 1299 // producer-side bug in llvm. See llvm.org/pr48087. 1300 case DW_OP_constu: 1301 stack.push_back(Scalar(opcodes.GetULEB128(&offset))); 1302 break; 1303 case DW_OP_consts: 1304 stack.push_back(Scalar(opcodes.GetSLEB128(&offset))); 1305 break; 1306 1307 // OPCODE: DW_OP_dup 1308 // OPERANDS: none 1309 // DESCRIPTION: duplicates the value at the top of the stack 1310 case DW_OP_dup: 1311 if (stack.empty()) { 1312 if (error_ptr) 1313 error_ptr->SetErrorString("Expression stack empty for DW_OP_dup."); 1314 return false; 1315 } else 1316 stack.push_back(stack.back()); 1317 break; 1318 1319 // OPCODE: DW_OP_drop 1320 // OPERANDS: none 1321 // DESCRIPTION: pops the value at the top of the stack 1322 case DW_OP_drop: 1323 if (stack.empty()) { 1324 if (error_ptr) 1325 error_ptr->SetErrorString("Expression stack empty for DW_OP_drop."); 1326 return false; 1327 } else 1328 stack.pop_back(); 1329 break; 1330 1331 // OPCODE: DW_OP_over 1332 // OPERANDS: none 1333 // DESCRIPTION: Duplicates the entry currently second in the stack at 1334 // the top of the stack. 1335 case DW_OP_over: 1336 if (stack.size() < 2) { 1337 if (error_ptr) 1338 error_ptr->SetErrorString( 1339 "Expression stack needs at least 2 items for DW_OP_over."); 1340 return false; 1341 } else 1342 stack.push_back(stack[stack.size() - 2]); 1343 break; 1344 1345 // OPCODE: DW_OP_pick 1346 // OPERANDS: uint8_t index into the current stack 1347 // DESCRIPTION: The stack entry with the specified index (0 through 255, 1348 // inclusive) is pushed on the stack 1349 case DW_OP_pick: { 1350 uint8_t pick_idx = opcodes.GetU8(&offset); 1351 if (pick_idx < stack.size()) 1352 stack.push_back(stack[stack.size() - 1 - pick_idx]); 1353 else { 1354 if (error_ptr) 1355 error_ptr->SetErrorStringWithFormat( 1356 "Index %u out of range for DW_OP_pick.\n", pick_idx); 1357 return false; 1358 } 1359 } break; 1360 1361 // OPCODE: DW_OP_swap 1362 // OPERANDS: none 1363 // DESCRIPTION: swaps the top two stack entries. The entry at the top 1364 // of the stack becomes the second stack entry, and the second entry 1365 // becomes the top of the stack 1366 case DW_OP_swap: 1367 if (stack.size() < 2) { 1368 if (error_ptr) 1369 error_ptr->SetErrorString( 1370 "Expression stack needs at least 2 items for DW_OP_swap."); 1371 return false; 1372 } else { 1373 tmp = stack.back(); 1374 stack.back() = stack[stack.size() - 2]; 1375 stack[stack.size() - 2] = tmp; 1376 } 1377 break; 1378 1379 // OPCODE: DW_OP_rot 1380 // OPERANDS: none 1381 // DESCRIPTION: Rotates the first three stack entries. The entry at 1382 // the top of the stack becomes the third stack entry, the second entry 1383 // becomes the top of the stack, and the third entry becomes the second 1384 // entry. 1385 case DW_OP_rot: 1386 if (stack.size() < 3) { 1387 if (error_ptr) 1388 error_ptr->SetErrorString( 1389 "Expression stack needs at least 3 items for DW_OP_rot."); 1390 return false; 1391 } else { 1392 size_t last_idx = stack.size() - 1; 1393 Value old_top = stack[last_idx]; 1394 stack[last_idx] = stack[last_idx - 1]; 1395 stack[last_idx - 1] = stack[last_idx - 2]; 1396 stack[last_idx - 2] = old_top; 1397 } 1398 break; 1399 1400 // OPCODE: DW_OP_abs 1401 // OPERANDS: none 1402 // DESCRIPTION: pops the top stack entry, interprets it as a signed 1403 // value and pushes its absolute value. If the absolute value can not be 1404 // represented, the result is undefined. 1405 case DW_OP_abs: 1406 if (stack.empty()) { 1407 if (error_ptr) 1408 error_ptr->SetErrorString( 1409 "Expression stack needs at least 1 item for DW_OP_abs."); 1410 return false; 1411 } else if (!stack.back().ResolveValue(exe_ctx).AbsoluteValue()) { 1412 if (error_ptr) 1413 error_ptr->SetErrorString( 1414 "Failed to take the absolute value of the first stack item."); 1415 return false; 1416 } 1417 break; 1418 1419 // OPCODE: DW_OP_and 1420 // OPERANDS: none 1421 // DESCRIPTION: pops the top two stack values, performs a bitwise and 1422 // operation on the two, and pushes the result. 1423 case DW_OP_and: 1424 if (stack.size() < 2) { 1425 if (error_ptr) 1426 error_ptr->SetErrorString( 1427 "Expression stack needs at least 2 items for DW_OP_and."); 1428 return false; 1429 } else { 1430 tmp = stack.back(); 1431 stack.pop_back(); 1432 stack.back().ResolveValue(exe_ctx) = 1433 stack.back().ResolveValue(exe_ctx) & tmp.ResolveValue(exe_ctx); 1434 } 1435 break; 1436 1437 // OPCODE: DW_OP_div 1438 // OPERANDS: none 1439 // DESCRIPTION: pops the top two stack values, divides the former second 1440 // entry by the former top of the stack using signed division, and pushes 1441 // the result. 1442 case DW_OP_div: 1443 if (stack.size() < 2) { 1444 if (error_ptr) 1445 error_ptr->SetErrorString( 1446 "Expression stack needs at least 2 items for DW_OP_div."); 1447 return false; 1448 } else { 1449 tmp = stack.back(); 1450 if (tmp.ResolveValue(exe_ctx).IsZero()) { 1451 if (error_ptr) 1452 error_ptr->SetErrorString("Divide by zero."); 1453 return false; 1454 } else { 1455 stack.pop_back(); 1456 Scalar divisor, dividend; 1457 divisor = tmp.ResolveValue(exe_ctx); 1458 dividend = stack.back().ResolveValue(exe_ctx); 1459 divisor.MakeSigned(); 1460 dividend.MakeSigned(); 1461 stack.back() = dividend / divisor; 1462 if (!stack.back().ResolveValue(exe_ctx).IsValid()) { 1463 if (error_ptr) 1464 error_ptr->SetErrorString("Divide failed."); 1465 return false; 1466 } 1467 } 1468 } 1469 break; 1470 1471 // OPCODE: DW_OP_minus 1472 // OPERANDS: none 1473 // DESCRIPTION: pops the top two stack values, subtracts the former top 1474 // of the stack from the former second entry, and pushes the result. 1475 case DW_OP_minus: 1476 if (stack.size() < 2) { 1477 if (error_ptr) 1478 error_ptr->SetErrorString( 1479 "Expression stack needs at least 2 items for DW_OP_minus."); 1480 return false; 1481 } else { 1482 tmp = stack.back(); 1483 stack.pop_back(); 1484 stack.back().ResolveValue(exe_ctx) = 1485 stack.back().ResolveValue(exe_ctx) - tmp.ResolveValue(exe_ctx); 1486 } 1487 break; 1488 1489 // OPCODE: DW_OP_mod 1490 // OPERANDS: none 1491 // DESCRIPTION: pops the top two stack values and pushes the result of 1492 // the calculation: former second stack entry modulo the former top of the 1493 // stack. 1494 case DW_OP_mod: 1495 if (stack.size() < 2) { 1496 if (error_ptr) 1497 error_ptr->SetErrorString( 1498 "Expression stack needs at least 2 items for DW_OP_mod."); 1499 return false; 1500 } else { 1501 tmp = stack.back(); 1502 stack.pop_back(); 1503 stack.back().ResolveValue(exe_ctx) = 1504 stack.back().ResolveValue(exe_ctx) % tmp.ResolveValue(exe_ctx); 1505 } 1506 break; 1507 1508 // OPCODE: DW_OP_mul 1509 // OPERANDS: none 1510 // DESCRIPTION: pops the top two stack entries, multiplies them 1511 // together, and pushes the result. 1512 case DW_OP_mul: 1513 if (stack.size() < 2) { 1514 if (error_ptr) 1515 error_ptr->SetErrorString( 1516 "Expression stack needs at least 2 items for DW_OP_mul."); 1517 return false; 1518 } else { 1519 tmp = stack.back(); 1520 stack.pop_back(); 1521 stack.back().ResolveValue(exe_ctx) = 1522 stack.back().ResolveValue(exe_ctx) * tmp.ResolveValue(exe_ctx); 1523 } 1524 break; 1525 1526 // OPCODE: DW_OP_neg 1527 // OPERANDS: none 1528 // DESCRIPTION: pops the top stack entry, and pushes its negation. 1529 case DW_OP_neg: 1530 if (stack.empty()) { 1531 if (error_ptr) 1532 error_ptr->SetErrorString( 1533 "Expression stack needs at least 1 item for DW_OP_neg."); 1534 return false; 1535 } else { 1536 if (!stack.back().ResolveValue(exe_ctx).UnaryNegate()) { 1537 if (error_ptr) 1538 error_ptr->SetErrorString("Unary negate failed."); 1539 return false; 1540 } 1541 } 1542 break; 1543 1544 // OPCODE: DW_OP_not 1545 // OPERANDS: none 1546 // DESCRIPTION: pops the top stack entry, and pushes its bitwise 1547 // complement 1548 case DW_OP_not: 1549 if (stack.empty()) { 1550 if (error_ptr) 1551 error_ptr->SetErrorString( 1552 "Expression stack needs at least 1 item for DW_OP_not."); 1553 return false; 1554 } else { 1555 if (!stack.back().ResolveValue(exe_ctx).OnesComplement()) { 1556 if (error_ptr) 1557 error_ptr->SetErrorString("Logical NOT failed."); 1558 return false; 1559 } 1560 } 1561 break; 1562 1563 // OPCODE: DW_OP_or 1564 // OPERANDS: none 1565 // DESCRIPTION: pops the top two stack entries, performs a bitwise or 1566 // operation on the two, and pushes the result. 1567 case DW_OP_or: 1568 if (stack.size() < 2) { 1569 if (error_ptr) 1570 error_ptr->SetErrorString( 1571 "Expression stack needs at least 2 items for DW_OP_or."); 1572 return false; 1573 } else { 1574 tmp = stack.back(); 1575 stack.pop_back(); 1576 stack.back().ResolveValue(exe_ctx) = 1577 stack.back().ResolveValue(exe_ctx) | tmp.ResolveValue(exe_ctx); 1578 } 1579 break; 1580 1581 // OPCODE: DW_OP_plus 1582 // OPERANDS: none 1583 // DESCRIPTION: pops the top two stack entries, adds them together, and 1584 // pushes the result. 1585 case DW_OP_plus: 1586 if (stack.size() < 2) { 1587 if (error_ptr) 1588 error_ptr->SetErrorString( 1589 "Expression stack needs at least 2 items for DW_OP_plus."); 1590 return false; 1591 } else { 1592 tmp = stack.back(); 1593 stack.pop_back(); 1594 stack.back().GetScalar() += tmp.GetScalar(); 1595 } 1596 break; 1597 1598 // OPCODE: DW_OP_plus_uconst 1599 // OPERANDS: none 1600 // DESCRIPTION: pops the top stack entry, adds it to the unsigned LEB128 1601 // constant operand and pushes the result. 1602 case DW_OP_plus_uconst: 1603 if (stack.empty()) { 1604 if (error_ptr) 1605 error_ptr->SetErrorString( 1606 "Expression stack needs at least 1 item for DW_OP_plus_uconst."); 1607 return false; 1608 } else { 1609 const uint64_t uconst_value = opcodes.GetULEB128(&offset); 1610 // Implicit conversion from a UINT to a Scalar... 1611 stack.back().GetScalar() += uconst_value; 1612 if (!stack.back().GetScalar().IsValid()) { 1613 if (error_ptr) 1614 error_ptr->SetErrorString("DW_OP_plus_uconst failed."); 1615 return false; 1616 } 1617 } 1618 break; 1619 1620 // OPCODE: DW_OP_shl 1621 // OPERANDS: none 1622 // DESCRIPTION: pops the top two stack entries, shifts the former 1623 // second entry left by the number of bits specified by the former top of 1624 // the stack, and pushes the result. 1625 case DW_OP_shl: 1626 if (stack.size() < 2) { 1627 if (error_ptr) 1628 error_ptr->SetErrorString( 1629 "Expression stack needs at least 2 items for DW_OP_shl."); 1630 return false; 1631 } else { 1632 tmp = stack.back(); 1633 stack.pop_back(); 1634 stack.back().ResolveValue(exe_ctx) <<= tmp.ResolveValue(exe_ctx); 1635 } 1636 break; 1637 1638 // OPCODE: DW_OP_shr 1639 // OPERANDS: none 1640 // DESCRIPTION: pops the top two stack entries, shifts the former second 1641 // entry right logically (filling with zero bits) by the number of bits 1642 // specified by the former top of the stack, and pushes the result. 1643 case DW_OP_shr: 1644 if (stack.size() < 2) { 1645 if (error_ptr) 1646 error_ptr->SetErrorString( 1647 "Expression stack needs at least 2 items for DW_OP_shr."); 1648 return false; 1649 } else { 1650 tmp = stack.back(); 1651 stack.pop_back(); 1652 if (!stack.back().ResolveValue(exe_ctx).ShiftRightLogical( 1653 tmp.ResolveValue(exe_ctx))) { 1654 if (error_ptr) 1655 error_ptr->SetErrorString("DW_OP_shr failed."); 1656 return false; 1657 } 1658 } 1659 break; 1660 1661 // OPCODE: DW_OP_shra 1662 // OPERANDS: none 1663 // DESCRIPTION: pops the top two stack entries, shifts the former second 1664 // entry right arithmetically (divide the magnitude by 2, keep the same 1665 // sign for the result) by the number of bits specified by the former top 1666 // of the stack, and pushes the result. 1667 case DW_OP_shra: 1668 if (stack.size() < 2) { 1669 if (error_ptr) 1670 error_ptr->SetErrorString( 1671 "Expression stack needs at least 2 items for DW_OP_shra."); 1672 return false; 1673 } else { 1674 tmp = stack.back(); 1675 stack.pop_back(); 1676 stack.back().ResolveValue(exe_ctx) >>= tmp.ResolveValue(exe_ctx); 1677 } 1678 break; 1679 1680 // OPCODE: DW_OP_xor 1681 // OPERANDS: none 1682 // DESCRIPTION: pops the top two stack entries, performs the bitwise 1683 // exclusive-or operation on the two, and pushes the result. 1684 case DW_OP_xor: 1685 if (stack.size() < 2) { 1686 if (error_ptr) 1687 error_ptr->SetErrorString( 1688 "Expression stack needs at least 2 items for DW_OP_xor."); 1689 return false; 1690 } else { 1691 tmp = stack.back(); 1692 stack.pop_back(); 1693 stack.back().ResolveValue(exe_ctx) = 1694 stack.back().ResolveValue(exe_ctx) ^ tmp.ResolveValue(exe_ctx); 1695 } 1696 break; 1697 1698 // OPCODE: DW_OP_skip 1699 // OPERANDS: int16_t 1700 // DESCRIPTION: An unconditional branch. Its single operand is a 2-byte 1701 // signed integer constant. The 2-byte constant is the number of bytes of 1702 // the DWARF expression to skip forward or backward from the current 1703 // operation, beginning after the 2-byte constant. 1704 case DW_OP_skip: { 1705 int16_t skip_offset = (int16_t)opcodes.GetU16(&offset); 1706 lldb::offset_t new_offset = offset + skip_offset; 1707 // New offset can point at the end of the data, in this case we should 1708 // terminate the DWARF expression evaluation (will happen in the loop 1709 // condition). 1710 if (new_offset <= opcodes.GetByteSize()) 1711 offset = new_offset; 1712 else { 1713 if (error_ptr) 1714 error_ptr->SetErrorStringWithFormatv( 1715 "Invalid opcode offset in DW_OP_skip: {0}+({1}) > {2}", offset, 1716 skip_offset, opcodes.GetByteSize()); 1717 return false; 1718 } 1719 } break; 1720 1721 // OPCODE: DW_OP_bra 1722 // OPERANDS: int16_t 1723 // DESCRIPTION: A conditional branch. Its single operand is a 2-byte 1724 // signed integer constant. This operation pops the top of stack. If the 1725 // value popped is not the constant 0, the 2-byte constant operand is the 1726 // number of bytes of the DWARF expression to skip forward or backward from 1727 // the current operation, beginning after the 2-byte constant. 1728 case DW_OP_bra: 1729 if (stack.empty()) { 1730 if (error_ptr) 1731 error_ptr->SetErrorString( 1732 "Expression stack needs at least 1 item for DW_OP_bra."); 1733 return false; 1734 } else { 1735 tmp = stack.back(); 1736 stack.pop_back(); 1737 int16_t bra_offset = (int16_t)opcodes.GetU16(&offset); 1738 Scalar zero(0); 1739 if (tmp.ResolveValue(exe_ctx) != zero) { 1740 lldb::offset_t new_offset = offset + bra_offset; 1741 // New offset can point at the end of the data, in this case we should 1742 // terminate the DWARF expression evaluation (will happen in the loop 1743 // condition). 1744 if (new_offset <= opcodes.GetByteSize()) 1745 offset = new_offset; 1746 else { 1747 if (error_ptr) 1748 error_ptr->SetErrorStringWithFormatv( 1749 "Invalid opcode offset in DW_OP_bra: {0}+({1}) > {2}", offset, 1750 bra_offset, opcodes.GetByteSize()); 1751 return false; 1752 } 1753 } 1754 } 1755 break; 1756 1757 // OPCODE: DW_OP_eq 1758 // OPERANDS: none 1759 // DESCRIPTION: pops the top two stack values, compares using the 1760 // equals (==) operator. 1761 // STACK RESULT: push the constant value 1 onto the stack if the result 1762 // of the operation is true or the constant value 0 if the result of the 1763 // operation is false. 1764 case DW_OP_eq: 1765 if (stack.size() < 2) { 1766 if (error_ptr) 1767 error_ptr->SetErrorString( 1768 "Expression stack needs at least 2 items for DW_OP_eq."); 1769 return false; 1770 } else { 1771 tmp = stack.back(); 1772 stack.pop_back(); 1773 stack.back().ResolveValue(exe_ctx) = 1774 stack.back().ResolveValue(exe_ctx) == tmp.ResolveValue(exe_ctx); 1775 } 1776 break; 1777 1778 // OPCODE: DW_OP_ge 1779 // OPERANDS: none 1780 // DESCRIPTION: pops the top two stack values, compares using the 1781 // greater than or equal to (>=) operator. 1782 // STACK RESULT: push the constant value 1 onto the stack if the result 1783 // of the operation is true or the constant value 0 if the result of the 1784 // operation is false. 1785 case DW_OP_ge: 1786 if (stack.size() < 2) { 1787 if (error_ptr) 1788 error_ptr->SetErrorString( 1789 "Expression stack needs at least 2 items for DW_OP_ge."); 1790 return false; 1791 } else { 1792 tmp = stack.back(); 1793 stack.pop_back(); 1794 stack.back().ResolveValue(exe_ctx) = 1795 stack.back().ResolveValue(exe_ctx) >= tmp.ResolveValue(exe_ctx); 1796 } 1797 break; 1798 1799 // OPCODE: DW_OP_gt 1800 // OPERANDS: none 1801 // DESCRIPTION: pops the top two stack values, compares using the 1802 // greater than (>) operator. 1803 // STACK RESULT: push the constant value 1 onto the stack if the result 1804 // of the operation is true or the constant value 0 if the result of the 1805 // operation is false. 1806 case DW_OP_gt: 1807 if (stack.size() < 2) { 1808 if (error_ptr) 1809 error_ptr->SetErrorString( 1810 "Expression stack needs at least 2 items for DW_OP_gt."); 1811 return false; 1812 } else { 1813 tmp = stack.back(); 1814 stack.pop_back(); 1815 stack.back().ResolveValue(exe_ctx) = 1816 stack.back().ResolveValue(exe_ctx) > tmp.ResolveValue(exe_ctx); 1817 } 1818 break; 1819 1820 // OPCODE: DW_OP_le 1821 // OPERANDS: none 1822 // DESCRIPTION: pops the top two stack values, compares using the 1823 // less than or equal to (<=) operator. 1824 // STACK RESULT: push the constant value 1 onto the stack if the result 1825 // of the operation is true or the constant value 0 if the result of the 1826 // operation is false. 1827 case DW_OP_le: 1828 if (stack.size() < 2) { 1829 if (error_ptr) 1830 error_ptr->SetErrorString( 1831 "Expression stack needs at least 2 items for DW_OP_le."); 1832 return false; 1833 } else { 1834 tmp = stack.back(); 1835 stack.pop_back(); 1836 stack.back().ResolveValue(exe_ctx) = 1837 stack.back().ResolveValue(exe_ctx) <= tmp.ResolveValue(exe_ctx); 1838 } 1839 break; 1840 1841 // OPCODE: DW_OP_lt 1842 // OPERANDS: none 1843 // DESCRIPTION: pops the top two stack values, compares using the 1844 // less than (<) operator. 1845 // STACK RESULT: push the constant value 1 onto the stack if the result 1846 // of the operation is true or the constant value 0 if the result of the 1847 // operation is false. 1848 case DW_OP_lt: 1849 if (stack.size() < 2) { 1850 if (error_ptr) 1851 error_ptr->SetErrorString( 1852 "Expression stack needs at least 2 items for DW_OP_lt."); 1853 return false; 1854 } else { 1855 tmp = stack.back(); 1856 stack.pop_back(); 1857 stack.back().ResolveValue(exe_ctx) = 1858 stack.back().ResolveValue(exe_ctx) < tmp.ResolveValue(exe_ctx); 1859 } 1860 break; 1861 1862 // OPCODE: DW_OP_ne 1863 // OPERANDS: none 1864 // DESCRIPTION: pops the top two stack values, compares using the 1865 // not equal (!=) operator. 1866 // STACK RESULT: push the constant value 1 onto the stack if the result 1867 // of the operation is true or the constant value 0 if the result of the 1868 // operation is false. 1869 case DW_OP_ne: 1870 if (stack.size() < 2) { 1871 if (error_ptr) 1872 error_ptr->SetErrorString( 1873 "Expression stack needs at least 2 items for DW_OP_ne."); 1874 return false; 1875 } else { 1876 tmp = stack.back(); 1877 stack.pop_back(); 1878 stack.back().ResolveValue(exe_ctx) = 1879 stack.back().ResolveValue(exe_ctx) != tmp.ResolveValue(exe_ctx); 1880 } 1881 break; 1882 1883 // OPCODE: DW_OP_litn 1884 // OPERANDS: none 1885 // DESCRIPTION: encode the unsigned literal values from 0 through 31. 1886 // STACK RESULT: push the unsigned literal constant value onto the top 1887 // of the stack. 1888 case DW_OP_lit0: 1889 case DW_OP_lit1: 1890 case DW_OP_lit2: 1891 case DW_OP_lit3: 1892 case DW_OP_lit4: 1893 case DW_OP_lit5: 1894 case DW_OP_lit6: 1895 case DW_OP_lit7: 1896 case DW_OP_lit8: 1897 case DW_OP_lit9: 1898 case DW_OP_lit10: 1899 case DW_OP_lit11: 1900 case DW_OP_lit12: 1901 case DW_OP_lit13: 1902 case DW_OP_lit14: 1903 case DW_OP_lit15: 1904 case DW_OP_lit16: 1905 case DW_OP_lit17: 1906 case DW_OP_lit18: 1907 case DW_OP_lit19: 1908 case DW_OP_lit20: 1909 case DW_OP_lit21: 1910 case DW_OP_lit22: 1911 case DW_OP_lit23: 1912 case DW_OP_lit24: 1913 case DW_OP_lit25: 1914 case DW_OP_lit26: 1915 case DW_OP_lit27: 1916 case DW_OP_lit28: 1917 case DW_OP_lit29: 1918 case DW_OP_lit30: 1919 case DW_OP_lit31: 1920 stack.push_back(to_generic(op - DW_OP_lit0)); 1921 break; 1922 1923 // OPCODE: DW_OP_regN 1924 // OPERANDS: none 1925 // DESCRIPTION: Push the value in register n on the top of the stack. 1926 case DW_OP_reg0: 1927 case DW_OP_reg1: 1928 case DW_OP_reg2: 1929 case DW_OP_reg3: 1930 case DW_OP_reg4: 1931 case DW_OP_reg5: 1932 case DW_OP_reg6: 1933 case DW_OP_reg7: 1934 case DW_OP_reg8: 1935 case DW_OP_reg9: 1936 case DW_OP_reg10: 1937 case DW_OP_reg11: 1938 case DW_OP_reg12: 1939 case DW_OP_reg13: 1940 case DW_OP_reg14: 1941 case DW_OP_reg15: 1942 case DW_OP_reg16: 1943 case DW_OP_reg17: 1944 case DW_OP_reg18: 1945 case DW_OP_reg19: 1946 case DW_OP_reg20: 1947 case DW_OP_reg21: 1948 case DW_OP_reg22: 1949 case DW_OP_reg23: 1950 case DW_OP_reg24: 1951 case DW_OP_reg25: 1952 case DW_OP_reg26: 1953 case DW_OP_reg27: 1954 case DW_OP_reg28: 1955 case DW_OP_reg29: 1956 case DW_OP_reg30: 1957 case DW_OP_reg31: { 1958 dwarf4_location_description_kind = Register; 1959 reg_num = op - DW_OP_reg0; 1960 1961 if (ReadRegisterValueAsScalar(reg_ctx, reg_kind, reg_num, error_ptr, tmp)) 1962 stack.push_back(tmp); 1963 else 1964 return false; 1965 } break; 1966 // OPCODE: DW_OP_regx 1967 // OPERANDS: 1968 // ULEB128 literal operand that encodes the register. 1969 // DESCRIPTION: Push the value in register on the top of the stack. 1970 case DW_OP_regx: { 1971 dwarf4_location_description_kind = Register; 1972 reg_num = opcodes.GetULEB128(&offset); 1973 if (ReadRegisterValueAsScalar(reg_ctx, reg_kind, reg_num, error_ptr, tmp)) 1974 stack.push_back(tmp); 1975 else 1976 return false; 1977 } break; 1978 1979 // OPCODE: DW_OP_bregN 1980 // OPERANDS: 1981 // SLEB128 offset from register N 1982 // DESCRIPTION: Value is in memory at the address specified by register 1983 // N plus an offset. 1984 case DW_OP_breg0: 1985 case DW_OP_breg1: 1986 case DW_OP_breg2: 1987 case DW_OP_breg3: 1988 case DW_OP_breg4: 1989 case DW_OP_breg5: 1990 case DW_OP_breg6: 1991 case DW_OP_breg7: 1992 case DW_OP_breg8: 1993 case DW_OP_breg9: 1994 case DW_OP_breg10: 1995 case DW_OP_breg11: 1996 case DW_OP_breg12: 1997 case DW_OP_breg13: 1998 case DW_OP_breg14: 1999 case DW_OP_breg15: 2000 case DW_OP_breg16: 2001 case DW_OP_breg17: 2002 case DW_OP_breg18: 2003 case DW_OP_breg19: 2004 case DW_OP_breg20: 2005 case DW_OP_breg21: 2006 case DW_OP_breg22: 2007 case DW_OP_breg23: 2008 case DW_OP_breg24: 2009 case DW_OP_breg25: 2010 case DW_OP_breg26: 2011 case DW_OP_breg27: 2012 case DW_OP_breg28: 2013 case DW_OP_breg29: 2014 case DW_OP_breg30: 2015 case DW_OP_breg31: { 2016 reg_num = op - DW_OP_breg0; 2017 2018 if (ReadRegisterValueAsScalar(reg_ctx, reg_kind, reg_num, error_ptr, 2019 tmp)) { 2020 int64_t breg_offset = opcodes.GetSLEB128(&offset); 2021 tmp.ResolveValue(exe_ctx) += (uint64_t)breg_offset; 2022 tmp.ClearContext(); 2023 stack.push_back(tmp); 2024 stack.back().SetValueType(Value::ValueType::LoadAddress); 2025 } else 2026 return false; 2027 } break; 2028 // OPCODE: DW_OP_bregx 2029 // OPERANDS: 2 2030 // ULEB128 literal operand that encodes the register. 2031 // SLEB128 offset from register N 2032 // DESCRIPTION: Value is in memory at the address specified by register 2033 // N plus an offset. 2034 case DW_OP_bregx: { 2035 reg_num = opcodes.GetULEB128(&offset); 2036 2037 if (ReadRegisterValueAsScalar(reg_ctx, reg_kind, reg_num, error_ptr, 2038 tmp)) { 2039 int64_t breg_offset = opcodes.GetSLEB128(&offset); 2040 tmp.ResolveValue(exe_ctx) += (uint64_t)breg_offset; 2041 tmp.ClearContext(); 2042 stack.push_back(tmp); 2043 stack.back().SetValueType(Value::ValueType::LoadAddress); 2044 } else 2045 return false; 2046 } break; 2047 2048 case DW_OP_fbreg: 2049 if (exe_ctx) { 2050 if (frame) { 2051 Scalar value; 2052 if (frame->GetFrameBaseValue(value, error_ptr)) { 2053 int64_t fbreg_offset = opcodes.GetSLEB128(&offset); 2054 value += fbreg_offset; 2055 stack.push_back(value); 2056 stack.back().SetValueType(Value::ValueType::LoadAddress); 2057 } else 2058 return false; 2059 } else { 2060 if (error_ptr) 2061 error_ptr->SetErrorString( 2062 "Invalid stack frame in context for DW_OP_fbreg opcode."); 2063 return false; 2064 } 2065 } else { 2066 if (error_ptr) 2067 error_ptr->SetErrorString( 2068 "NULL execution context for DW_OP_fbreg.\n"); 2069 return false; 2070 } 2071 2072 break; 2073 2074 // OPCODE: DW_OP_nop 2075 // OPERANDS: none 2076 // DESCRIPTION: A place holder. It has no effect on the location stack 2077 // or any of its values. 2078 case DW_OP_nop: 2079 break; 2080 2081 // OPCODE: DW_OP_piece 2082 // OPERANDS: 1 2083 // ULEB128: byte size of the piece 2084 // DESCRIPTION: The operand describes the size in bytes of the piece of 2085 // the object referenced by the DWARF expression whose result is at the top 2086 // of the stack. If the piece is located in a register, but does not occupy 2087 // the entire register, the placement of the piece within that register is 2088 // defined by the ABI. 2089 // 2090 // Many compilers store a single variable in sets of registers, or store a 2091 // variable partially in memory and partially in registers. DW_OP_piece 2092 // provides a way of describing how large a part of a variable a particular 2093 // DWARF expression refers to. 2094 case DW_OP_piece: { 2095 LocationDescriptionKind piece_locdesc = dwarf4_location_description_kind; 2096 // Reset for the next piece. 2097 dwarf4_location_description_kind = Memory; 2098 2099 const uint64_t piece_byte_size = opcodes.GetULEB128(&offset); 2100 2101 if (piece_byte_size > 0) { 2102 Value curr_piece; 2103 2104 if (stack.empty()) { 2105 UpdateValueTypeFromLocationDescription( 2106 log, dwarf_cu, LocationDescriptionKind::Empty); 2107 // In a multi-piece expression, this means that the current piece is 2108 // not available. Fill with zeros for now by resizing the data and 2109 // appending it 2110 curr_piece.ResizeData(piece_byte_size); 2111 // Note that "0" is not a correct value for the unknown bits. 2112 // It would be better to also return a mask of valid bits together 2113 // with the expression result, so the debugger can print missing 2114 // members as "<optimized out>" or something. 2115 ::memset(curr_piece.GetBuffer().GetBytes(), 0, piece_byte_size); 2116 pieces.AppendDataToHostBuffer(curr_piece); 2117 } else { 2118 Status error; 2119 // Extract the current piece into "curr_piece" 2120 Value curr_piece_source_value(stack.back()); 2121 stack.pop_back(); 2122 UpdateValueTypeFromLocationDescription(log, dwarf_cu, piece_locdesc, 2123 &curr_piece_source_value); 2124 2125 const Value::ValueType curr_piece_source_value_type = 2126 curr_piece_source_value.GetValueType(); 2127 switch (curr_piece_source_value_type) { 2128 case Value::ValueType::Invalid: 2129 return false; 2130 case Value::ValueType::LoadAddress: 2131 if (process) { 2132 if (curr_piece.ResizeData(piece_byte_size) == piece_byte_size) { 2133 lldb::addr_t load_addr = 2134 curr_piece_source_value.GetScalar().ULongLong( 2135 LLDB_INVALID_ADDRESS); 2136 if (process->ReadMemory( 2137 load_addr, curr_piece.GetBuffer().GetBytes(), 2138 piece_byte_size, error) != piece_byte_size) { 2139 if (error_ptr) 2140 error_ptr->SetErrorStringWithFormat( 2141 "failed to read memory DW_OP_piece(%" PRIu64 2142 ") from 0x%" PRIx64, 2143 piece_byte_size, load_addr); 2144 return false; 2145 } 2146 } else { 2147 if (error_ptr) 2148 error_ptr->SetErrorStringWithFormat( 2149 "failed to resize the piece memory buffer for " 2150 "DW_OP_piece(%" PRIu64 ")", 2151 piece_byte_size); 2152 return false; 2153 } 2154 } 2155 break; 2156 2157 case Value::ValueType::FileAddress: 2158 case Value::ValueType::HostAddress: 2159 if (error_ptr) { 2160 lldb::addr_t addr = curr_piece_source_value.GetScalar().ULongLong( 2161 LLDB_INVALID_ADDRESS); 2162 error_ptr->SetErrorStringWithFormat( 2163 "failed to read memory DW_OP_piece(%" PRIu64 2164 ") from %s address 0x%" PRIx64, 2165 piece_byte_size, curr_piece_source_value.GetValueType() == 2166 Value::ValueType::FileAddress 2167 ? "file" 2168 : "host", 2169 addr); 2170 } 2171 return false; 2172 2173 case Value::ValueType::Scalar: { 2174 uint32_t bit_size = piece_byte_size * 8; 2175 uint32_t bit_offset = 0; 2176 Scalar &scalar = curr_piece_source_value.GetScalar(); 2177 if (!scalar.ExtractBitfield( 2178 bit_size, bit_offset)) { 2179 if (error_ptr) 2180 error_ptr->SetErrorStringWithFormat( 2181 "unable to extract %" PRIu64 " bytes from a %" PRIu64 2182 " byte scalar value.", 2183 piece_byte_size, 2184 (uint64_t)curr_piece_source_value.GetScalar() 2185 .GetByteSize()); 2186 return false; 2187 } 2188 // Create curr_piece with bit_size. By default Scalar 2189 // grows to the nearest host integer type. 2190 llvm::APInt fail_value(1, 0, false); 2191 llvm::APInt ap_int = scalar.UInt128(fail_value); 2192 assert(ap_int.getBitWidth() >= bit_size); 2193 llvm::ArrayRef<uint64_t> buf{ap_int.getRawData(), 2194 ap_int.getNumWords()}; 2195 curr_piece.GetScalar() = Scalar(llvm::APInt(bit_size, buf)); 2196 } break; 2197 } 2198 2199 // Check if this is the first piece? 2200 if (op_piece_offset == 0) { 2201 // This is the first piece, we should push it back onto the stack 2202 // so subsequent pieces will be able to access this piece and add 2203 // to it. 2204 if (pieces.AppendDataToHostBuffer(curr_piece) == 0) { 2205 if (error_ptr) 2206 error_ptr->SetErrorString("failed to append piece data"); 2207 return false; 2208 } 2209 } else { 2210 // If this is the second or later piece there should be a value on 2211 // the stack. 2212 if (pieces.GetBuffer().GetByteSize() != op_piece_offset) { 2213 if (error_ptr) 2214 error_ptr->SetErrorStringWithFormat( 2215 "DW_OP_piece for offset %" PRIu64 2216 " but top of stack is of size %" PRIu64, 2217 op_piece_offset, pieces.GetBuffer().GetByteSize()); 2218 return false; 2219 } 2220 2221 if (pieces.AppendDataToHostBuffer(curr_piece) == 0) { 2222 if (error_ptr) 2223 error_ptr->SetErrorString("failed to append piece data"); 2224 return false; 2225 } 2226 } 2227 } 2228 op_piece_offset += piece_byte_size; 2229 } 2230 } break; 2231 2232 case DW_OP_bit_piece: // 0x9d ULEB128 bit size, ULEB128 bit offset (DWARF3); 2233 if (stack.size() < 1) { 2234 UpdateValueTypeFromLocationDescription(log, dwarf_cu, 2235 LocationDescriptionKind::Empty); 2236 // Reset for the next piece. 2237 dwarf4_location_description_kind = Memory; 2238 if (error_ptr) 2239 error_ptr->SetErrorString( 2240 "Expression stack needs at least 1 item for DW_OP_bit_piece."); 2241 return false; 2242 } else { 2243 UpdateValueTypeFromLocationDescription( 2244 log, dwarf_cu, dwarf4_location_description_kind, &stack.back()); 2245 // Reset for the next piece. 2246 dwarf4_location_description_kind = Memory; 2247 const uint64_t piece_bit_size = opcodes.GetULEB128(&offset); 2248 const uint64_t piece_bit_offset = opcodes.GetULEB128(&offset); 2249 switch (stack.back().GetValueType()) { 2250 case Value::ValueType::Invalid: 2251 return false; 2252 case Value::ValueType::Scalar: { 2253 if (!stack.back().GetScalar().ExtractBitfield(piece_bit_size, 2254 piece_bit_offset)) { 2255 if (error_ptr) 2256 error_ptr->SetErrorStringWithFormat( 2257 "unable to extract %" PRIu64 " bit value with %" PRIu64 2258 " bit offset from a %" PRIu64 " bit scalar value.", 2259 piece_bit_size, piece_bit_offset, 2260 (uint64_t)(stack.back().GetScalar().GetByteSize() * 8)); 2261 return false; 2262 } 2263 } break; 2264 2265 case Value::ValueType::FileAddress: 2266 case Value::ValueType::LoadAddress: 2267 case Value::ValueType::HostAddress: 2268 if (error_ptr) { 2269 error_ptr->SetErrorStringWithFormat( 2270 "unable to extract DW_OP_bit_piece(bit_size = %" PRIu64 2271 ", bit_offset = %" PRIu64 ") from an address value.", 2272 piece_bit_size, piece_bit_offset); 2273 } 2274 return false; 2275 } 2276 } 2277 break; 2278 2279 // OPCODE: DW_OP_implicit_value 2280 // OPERANDS: 2 2281 // ULEB128 size of the value block in bytes 2282 // uint8_t* block bytes encoding value in target's memory 2283 // representation 2284 // DESCRIPTION: Value is immediately stored in block in the debug info with 2285 // the memory representation of the target. 2286 case DW_OP_implicit_value: { 2287 dwarf4_location_description_kind = Implicit; 2288 2289 const uint32_t len = opcodes.GetULEB128(&offset); 2290 const void *data = opcodes.GetData(&offset, len); 2291 2292 if (!data) { 2293 LLDB_LOG(log, "Evaluate_DW_OP_implicit_value: could not be read data"); 2294 LLDB_ERRORF(error_ptr, "Could not evaluate %s.", 2295 DW_OP_value_to_name(op)); 2296 return false; 2297 } 2298 2299 Value result(data, len); 2300 stack.push_back(result); 2301 break; 2302 } 2303 2304 case DW_OP_implicit_pointer: { 2305 dwarf4_location_description_kind = Implicit; 2306 LLDB_ERRORF(error_ptr, "Could not evaluate %s.", DW_OP_value_to_name(op)); 2307 return false; 2308 } 2309 2310 // OPCODE: DW_OP_push_object_address 2311 // OPERANDS: none 2312 // DESCRIPTION: Pushes the address of the object currently being 2313 // evaluated as part of evaluation of a user presented expression. This 2314 // object may correspond to an independent variable described by its own 2315 // DIE or it may be a component of an array, structure, or class whose 2316 // address has been dynamically determined by an earlier step during user 2317 // expression evaluation. 2318 case DW_OP_push_object_address: 2319 if (object_address_ptr) 2320 stack.push_back(*object_address_ptr); 2321 else { 2322 if (error_ptr) 2323 error_ptr->SetErrorString("DW_OP_push_object_address used without " 2324 "specifying an object address"); 2325 return false; 2326 } 2327 break; 2328 2329 // OPCODE: DW_OP_call2 2330 // OPERANDS: 2331 // uint16_t compile unit relative offset of a DIE 2332 // DESCRIPTION: Performs subroutine calls during evaluation 2333 // of a DWARF expression. The operand is the 2-byte unsigned offset of a 2334 // debugging information entry in the current compilation unit. 2335 // 2336 // Operand interpretation is exactly like that for DW_FORM_ref2. 2337 // 2338 // This operation transfers control of DWARF expression evaluation to the 2339 // DW_AT_location attribute of the referenced DIE. If there is no such 2340 // attribute, then there is no effect. Execution of the DWARF expression of 2341 // a DW_AT_location attribute may add to and/or remove from values on the 2342 // stack. Execution returns to the point following the call when the end of 2343 // the attribute is reached. Values on the stack at the time of the call 2344 // may be used as parameters by the called expression and values left on 2345 // the stack by the called expression may be used as return values by prior 2346 // agreement between the calling and called expressions. 2347 case DW_OP_call2: 2348 if (error_ptr) 2349 error_ptr->SetErrorString("Unimplemented opcode DW_OP_call2."); 2350 return false; 2351 // OPCODE: DW_OP_call4 2352 // OPERANDS: 1 2353 // uint32_t compile unit relative offset of a DIE 2354 // DESCRIPTION: Performs a subroutine call during evaluation of a DWARF 2355 // expression. For DW_OP_call4, the operand is a 4-byte unsigned offset of 2356 // a debugging information entry in the current compilation unit. 2357 // 2358 // Operand interpretation DW_OP_call4 is exactly like that for 2359 // DW_FORM_ref4. 2360 // 2361 // This operation transfers control of DWARF expression evaluation to the 2362 // DW_AT_location attribute of the referenced DIE. If there is no such 2363 // attribute, then there is no effect. Execution of the DWARF expression of 2364 // a DW_AT_location attribute may add to and/or remove from values on the 2365 // stack. Execution returns to the point following the call when the end of 2366 // the attribute is reached. Values on the stack at the time of the call 2367 // may be used as parameters by the called expression and values left on 2368 // the stack by the called expression may be used as return values by prior 2369 // agreement between the calling and called expressions. 2370 case DW_OP_call4: 2371 if (error_ptr) 2372 error_ptr->SetErrorString("Unimplemented opcode DW_OP_call4."); 2373 return false; 2374 2375 // OPCODE: DW_OP_stack_value 2376 // OPERANDS: None 2377 // DESCRIPTION: Specifies that the object does not exist in memory but 2378 // rather is a constant value. The value from the top of the stack is the 2379 // value to be used. This is the actual object value and not the location. 2380 case DW_OP_stack_value: 2381 dwarf4_location_description_kind = Implicit; 2382 if (stack.empty()) { 2383 if (error_ptr) 2384 error_ptr->SetErrorString( 2385 "Expression stack needs at least 1 item for DW_OP_stack_value."); 2386 return false; 2387 } 2388 stack.back().SetValueType(Value::ValueType::Scalar); 2389 break; 2390 2391 // OPCODE: DW_OP_convert 2392 // OPERANDS: 1 2393 // A ULEB128 that is either a DIE offset of a 2394 // DW_TAG_base_type or 0 for the generic (pointer-sized) type. 2395 // 2396 // DESCRIPTION: Pop the top stack element, convert it to a 2397 // different type, and push the result. 2398 case DW_OP_convert: { 2399 if (stack.size() < 1) { 2400 if (error_ptr) 2401 error_ptr->SetErrorString( 2402 "Expression stack needs at least 1 item for DW_OP_convert."); 2403 return false; 2404 } 2405 const uint64_t die_offset = opcodes.GetULEB128(&offset); 2406 uint64_t bit_size; 2407 bool sign; 2408 if (die_offset == 0) { 2409 // The generic type has the size of an address on the target 2410 // machine and an unspecified signedness. Scalar has no 2411 // "unspecified signedness", so we use unsigned types. 2412 if (!module_sp) { 2413 if (error_ptr) 2414 error_ptr->SetErrorString("No module"); 2415 return false; 2416 } 2417 sign = false; 2418 bit_size = module_sp->GetArchitecture().GetAddressByteSize() * 8; 2419 if (!bit_size) { 2420 if (error_ptr) 2421 error_ptr->SetErrorString("unspecified architecture"); 2422 return false; 2423 } 2424 } else { 2425 // Retrieve the type DIE that the value is being converted to. This 2426 // offset is compile unit relative so we need to fix it up. 2427 const uint64_t abs_die_offset = die_offset + dwarf_cu->GetOffset(); 2428 // FIXME: the constness has annoying ripple effects. 2429 DWARFDIE die = const_cast<DWARFUnit *>(dwarf_cu)->GetDIE(abs_die_offset); 2430 if (!die) { 2431 if (error_ptr) 2432 error_ptr->SetErrorString("Cannot resolve DW_OP_convert type DIE"); 2433 return false; 2434 } 2435 uint64_t encoding = 2436 die.GetAttributeValueAsUnsigned(DW_AT_encoding, DW_ATE_hi_user); 2437 bit_size = die.GetAttributeValueAsUnsigned(DW_AT_byte_size, 0) * 8; 2438 if (!bit_size) 2439 bit_size = die.GetAttributeValueAsUnsigned(DW_AT_bit_size, 0); 2440 if (!bit_size) { 2441 if (error_ptr) 2442 error_ptr->SetErrorString("Unsupported type size in DW_OP_convert"); 2443 return false; 2444 } 2445 switch (encoding) { 2446 case DW_ATE_signed: 2447 case DW_ATE_signed_char: 2448 sign = true; 2449 break; 2450 case DW_ATE_unsigned: 2451 case DW_ATE_unsigned_char: 2452 sign = false; 2453 break; 2454 default: 2455 if (error_ptr) 2456 error_ptr->SetErrorString("Unsupported encoding in DW_OP_convert"); 2457 return false; 2458 } 2459 } 2460 Scalar &top = stack.back().ResolveValue(exe_ctx); 2461 top.TruncOrExtendTo(bit_size, sign); 2462 break; 2463 } 2464 2465 // OPCODE: DW_OP_call_frame_cfa 2466 // OPERANDS: None 2467 // DESCRIPTION: Specifies a DWARF expression that pushes the value of 2468 // the canonical frame address consistent with the call frame information 2469 // located in .debug_frame (or in the FDEs of the eh_frame section). 2470 case DW_OP_call_frame_cfa: 2471 if (frame) { 2472 // Note that we don't have to parse FDEs because this DWARF expression 2473 // is commonly evaluated with a valid stack frame. 2474 StackID id = frame->GetStackID(); 2475 addr_t cfa = id.GetCallFrameAddress(); 2476 if (cfa != LLDB_INVALID_ADDRESS) { 2477 stack.push_back(Scalar(cfa)); 2478 stack.back().SetValueType(Value::ValueType::LoadAddress); 2479 } else if (error_ptr) 2480 error_ptr->SetErrorString("Stack frame does not include a canonical " 2481 "frame address for DW_OP_call_frame_cfa " 2482 "opcode."); 2483 } else { 2484 if (error_ptr) 2485 error_ptr->SetErrorString("Invalid stack frame in context for " 2486 "DW_OP_call_frame_cfa opcode."); 2487 return false; 2488 } 2489 break; 2490 2491 // OPCODE: DW_OP_form_tls_address (or the old pre-DWARFv3 vendor extension 2492 // opcode, DW_OP_GNU_push_tls_address) 2493 // OPERANDS: none 2494 // DESCRIPTION: Pops a TLS offset from the stack, converts it to 2495 // an address in the current thread's thread-local storage block, and 2496 // pushes it on the stack. 2497 case DW_OP_form_tls_address: 2498 case DW_OP_GNU_push_tls_address: { 2499 if (stack.size() < 1) { 2500 if (error_ptr) { 2501 if (op == DW_OP_form_tls_address) 2502 error_ptr->SetErrorString( 2503 "DW_OP_form_tls_address needs an argument."); 2504 else 2505 error_ptr->SetErrorString( 2506 "DW_OP_GNU_push_tls_address needs an argument."); 2507 } 2508 return false; 2509 } 2510 2511 if (!exe_ctx || !module_sp) { 2512 if (error_ptr) 2513 error_ptr->SetErrorString("No context to evaluate TLS within."); 2514 return false; 2515 } 2516 2517 Thread *thread = exe_ctx->GetThreadPtr(); 2518 if (!thread) { 2519 if (error_ptr) 2520 error_ptr->SetErrorString("No thread to evaluate TLS within."); 2521 return false; 2522 } 2523 2524 // Lookup the TLS block address for this thread and module. 2525 const addr_t tls_file_addr = 2526 stack.back().GetScalar().ULongLong(LLDB_INVALID_ADDRESS); 2527 const addr_t tls_load_addr = 2528 thread->GetThreadLocalData(module_sp, tls_file_addr); 2529 2530 if (tls_load_addr == LLDB_INVALID_ADDRESS) { 2531 if (error_ptr) 2532 error_ptr->SetErrorString( 2533 "No TLS data currently exists for this thread."); 2534 return false; 2535 } 2536 2537 stack.back().GetScalar() = tls_load_addr; 2538 stack.back().SetValueType(Value::ValueType::LoadAddress); 2539 } break; 2540 2541 // OPCODE: DW_OP_addrx (DW_OP_GNU_addr_index is the legacy name.) 2542 // OPERANDS: 1 2543 // ULEB128: index to the .debug_addr section 2544 // DESCRIPTION: Pushes an address to the stack from the .debug_addr 2545 // section with the base address specified by the DW_AT_addr_base attribute 2546 // and the 0 based index is the ULEB128 encoded index. 2547 case DW_OP_addrx: 2548 case DW_OP_GNU_addr_index: { 2549 if (!dwarf_cu) { 2550 if (error_ptr) 2551 error_ptr->SetErrorString("DW_OP_GNU_addr_index found without a " 2552 "compile unit being specified"); 2553 return false; 2554 } 2555 uint64_t index = opcodes.GetULEB128(&offset); 2556 lldb::addr_t value = dwarf_cu->ReadAddressFromDebugAddrSection(index); 2557 stack.push_back(Scalar(value)); 2558 if (target && 2559 target->GetArchitecture().GetCore() == ArchSpec::eCore_wasm32) { 2560 // wasm file sections aren't mapped into memory, therefore addresses can 2561 // never point into a file section and are always LoadAddresses. 2562 stack.back().SetValueType(Value::ValueType::LoadAddress); 2563 } else { 2564 stack.back().SetValueType(Value::ValueType::FileAddress); 2565 } 2566 } break; 2567 2568 // OPCODE: DW_OP_GNU_const_index 2569 // OPERANDS: 1 2570 // ULEB128: index to the .debug_addr section 2571 // DESCRIPTION: Pushes an constant with the size of a machine address to 2572 // the stack from the .debug_addr section with the base address specified 2573 // by the DW_AT_addr_base attribute and the 0 based index is the ULEB128 2574 // encoded index. 2575 case DW_OP_GNU_const_index: { 2576 if (!dwarf_cu) { 2577 if (error_ptr) 2578 error_ptr->SetErrorString("DW_OP_GNU_const_index found without a " 2579 "compile unit being specified"); 2580 return false; 2581 } 2582 uint64_t index = opcodes.GetULEB128(&offset); 2583 lldb::addr_t value = dwarf_cu->ReadAddressFromDebugAddrSection(index); 2584 stack.push_back(Scalar(value)); 2585 } break; 2586 2587 case DW_OP_GNU_entry_value: 2588 case DW_OP_entry_value: { 2589 if (!Evaluate_DW_OP_entry_value(stack, exe_ctx, reg_ctx, opcodes, offset, 2590 error_ptr, log)) { 2591 LLDB_ERRORF(error_ptr, "Could not evaluate %s.", 2592 DW_OP_value_to_name(op)); 2593 return false; 2594 } 2595 break; 2596 } 2597 2598 default: 2599 if (dwarf_cu) { 2600 if (dwarf_cu->GetSymbolFileDWARF().ParseVendorDWARFOpcode( 2601 op, opcodes, offset, stack)) { 2602 break; 2603 } 2604 } 2605 if (error_ptr) 2606 error_ptr->SetErrorStringWithFormatv( 2607 "Unhandled opcode {0} in DWARFExpression", LocationAtom(op)); 2608 return false; 2609 } 2610 } 2611 2612 if (stack.empty()) { 2613 // Nothing on the stack, check if we created a piece value from DW_OP_piece 2614 // or DW_OP_bit_piece opcodes 2615 if (pieces.GetBuffer().GetByteSize()) { 2616 result = pieces; 2617 return true; 2618 } 2619 if (error_ptr) 2620 error_ptr->SetErrorString("Stack empty after evaluation."); 2621 return false; 2622 } 2623 2624 UpdateValueTypeFromLocationDescription( 2625 log, dwarf_cu, dwarf4_location_description_kind, &stack.back()); 2626 2627 if (log && log->GetVerbose()) { 2628 size_t count = stack.size(); 2629 LLDB_LOGF(log, 2630 "Stack after operation has %" PRIu64 " values:", (uint64_t)count); 2631 for (size_t i = 0; i < count; ++i) { 2632 StreamString new_value; 2633 new_value.Printf("[%" PRIu64 "]", (uint64_t)i); 2634 stack[i].Dump(&new_value); 2635 LLDB_LOGF(log, " %s", new_value.GetData()); 2636 } 2637 } 2638 result = stack.back(); 2639 return true; // Return true on success 2640 } 2641 2642 bool DWARFExpression::ParseDWARFLocationList( 2643 const DWARFUnit *dwarf_cu, const DataExtractor &data, 2644 DWARFExpressionList *location_list) { 2645 location_list->Clear(); 2646 std::unique_ptr<llvm::DWARFLocationTable> loctable_up = 2647 dwarf_cu->GetLocationTable(data); 2648 Log *log = GetLog(LLDBLog::Expressions); 2649 auto lookup_addr = 2650 [&](uint32_t index) -> std::optional<llvm::object::SectionedAddress> { 2651 addr_t address = dwarf_cu->ReadAddressFromDebugAddrSection(index); 2652 if (address == LLDB_INVALID_ADDRESS) 2653 return std::nullopt; 2654 return llvm::object::SectionedAddress{address}; 2655 }; 2656 auto process_list = [&](llvm::Expected<llvm::DWARFLocationExpression> loc) { 2657 if (!loc) { 2658 LLDB_LOG_ERROR(log, loc.takeError(), "{0}"); 2659 return true; 2660 } 2661 auto buffer_sp = 2662 std::make_shared<DataBufferHeap>(loc->Expr.data(), loc->Expr.size()); 2663 DWARFExpression expr = DWARFExpression(DataExtractor( 2664 buffer_sp, data.GetByteOrder(), data.GetAddressByteSize())); 2665 location_list->AddExpression(loc->Range->LowPC, loc->Range->HighPC, expr); 2666 return true; 2667 }; 2668 llvm::Error error = loctable_up->visitAbsoluteLocationList( 2669 0, llvm::object::SectionedAddress{dwarf_cu->GetBaseAddress()}, 2670 lookup_addr, process_list); 2671 location_list->Sort(); 2672 if (error) { 2673 LLDB_LOG_ERROR(log, std::move(error), "{0}"); 2674 return false; 2675 } 2676 return true; 2677 } 2678 2679 bool DWARFExpression::MatchesOperand( 2680 StackFrame &frame, const Instruction::Operand &operand) const { 2681 using namespace OperandMatchers; 2682 2683 RegisterContextSP reg_ctx_sp = frame.GetRegisterContext(); 2684 if (!reg_ctx_sp) { 2685 return false; 2686 } 2687 2688 DataExtractor opcodes(m_data); 2689 2690 lldb::offset_t op_offset = 0; 2691 uint8_t opcode = opcodes.GetU8(&op_offset); 2692 2693 if (opcode == DW_OP_fbreg) { 2694 int64_t offset = opcodes.GetSLEB128(&op_offset); 2695 2696 DWARFExpressionList *fb_expr = frame.GetFrameBaseExpression(nullptr); 2697 if (!fb_expr) { 2698 return false; 2699 } 2700 2701 auto recurse = [&frame, fb_expr](const Instruction::Operand &child) { 2702 return fb_expr->MatchesOperand(frame, child); 2703 }; 2704 2705 if (!offset && 2706 MatchUnaryOp(MatchOpType(Instruction::Operand::Type::Dereference), 2707 recurse)(operand)) { 2708 return true; 2709 } 2710 2711 return MatchUnaryOp( 2712 MatchOpType(Instruction::Operand::Type::Dereference), 2713 MatchBinaryOp(MatchOpType(Instruction::Operand::Type::Sum), 2714 MatchImmOp(offset), recurse))(operand); 2715 } 2716 2717 bool dereference = false; 2718 const RegisterInfo *reg = nullptr; 2719 int64_t offset = 0; 2720 2721 if (opcode >= DW_OP_reg0 && opcode <= DW_OP_reg31) { 2722 reg = reg_ctx_sp->GetRegisterInfo(m_reg_kind, opcode - DW_OP_reg0); 2723 } else if (opcode >= DW_OP_breg0 && opcode <= DW_OP_breg31) { 2724 offset = opcodes.GetSLEB128(&op_offset); 2725 reg = reg_ctx_sp->GetRegisterInfo(m_reg_kind, opcode - DW_OP_breg0); 2726 } else if (opcode == DW_OP_regx) { 2727 uint32_t reg_num = static_cast<uint32_t>(opcodes.GetULEB128(&op_offset)); 2728 reg = reg_ctx_sp->GetRegisterInfo(m_reg_kind, reg_num); 2729 } else if (opcode == DW_OP_bregx) { 2730 uint32_t reg_num = static_cast<uint32_t>(opcodes.GetULEB128(&op_offset)); 2731 offset = opcodes.GetSLEB128(&op_offset); 2732 reg = reg_ctx_sp->GetRegisterInfo(m_reg_kind, reg_num); 2733 } else { 2734 return false; 2735 } 2736 2737 if (!reg) { 2738 return false; 2739 } 2740 2741 if (dereference) { 2742 if (!offset && 2743 MatchUnaryOp(MatchOpType(Instruction::Operand::Type::Dereference), 2744 MatchRegOp(*reg))(operand)) { 2745 return true; 2746 } 2747 2748 return MatchUnaryOp( 2749 MatchOpType(Instruction::Operand::Type::Dereference), 2750 MatchBinaryOp(MatchOpType(Instruction::Operand::Type::Sum), 2751 MatchRegOp(*reg), 2752 MatchImmOp(offset)))(operand); 2753 } else { 2754 return MatchRegOp(*reg)(operand); 2755 } 2756 } 2757