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