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