1 //===-- DWARFFormValue.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 <cassert> 10 #include <optional> 11 12 #include "lldb/Core/Module.h" 13 #include "lldb/Core/dwarf.h" 14 #include "lldb/Symbol/ObjectFile.h" 15 #include "lldb/Utility/Stream.h" 16 17 #include "DWARFDebugInfo.h" 18 #include "DWARFFormValue.h" 19 #include "DWARFUnit.h" 20 21 using namespace lldb_private; 22 using namespace lldb_private::dwarf; 23 using namespace lldb_private::plugin::dwarf; 24 25 void DWARFFormValue::Clear() { 26 m_unit = nullptr; 27 m_form = dw_form_t(0); 28 m_value = ValueType(); 29 } 30 31 bool DWARFFormValue::ExtractValue(const DWARFDataExtractor &data, 32 lldb::offset_t *offset_ptr) { 33 if (m_form == DW_FORM_implicit_const) 34 return true; 35 36 bool indirect = false; 37 bool is_block = false; 38 m_value.data = nullptr; 39 // Read the value for the form into value and follow and DW_FORM_indirect 40 // instances we run into 41 do { 42 indirect = false; 43 switch (m_form) { 44 case DW_FORM_addr: 45 assert(m_unit); 46 m_value.uval = 47 data.GetMaxU64(offset_ptr, DWARFUnit::GetAddressByteSize(m_unit)); 48 break; 49 case DW_FORM_block1: 50 m_value.uval = data.GetU8(offset_ptr); 51 is_block = true; 52 break; 53 case DW_FORM_block2: 54 m_value.uval = data.GetU16(offset_ptr); 55 is_block = true; 56 break; 57 case DW_FORM_block4: 58 m_value.uval = data.GetU32(offset_ptr); 59 is_block = true; 60 break; 61 case DW_FORM_data16: 62 m_value.uval = 16; 63 is_block = true; 64 break; 65 case DW_FORM_exprloc: 66 case DW_FORM_block: 67 m_value.uval = data.GetULEB128(offset_ptr); 68 is_block = true; 69 break; 70 case DW_FORM_string: 71 m_value.cstr = data.GetCStr(offset_ptr); 72 break; 73 case DW_FORM_sdata: 74 m_value.sval = data.GetSLEB128(offset_ptr); 75 break; 76 case DW_FORM_strp: 77 case DW_FORM_line_strp: 78 case DW_FORM_sec_offset: 79 assert(m_unit); 80 m_value.uval = data.GetMaxU64( 81 offset_ptr, m_unit->GetFormParams().getDwarfOffsetByteSize()); 82 break; 83 case DW_FORM_addrx1: 84 case DW_FORM_strx1: 85 case DW_FORM_ref1: 86 case DW_FORM_data1: 87 case DW_FORM_flag: 88 m_value.uval = data.GetU8(offset_ptr); 89 break; 90 case DW_FORM_addrx2: 91 case DW_FORM_strx2: 92 case DW_FORM_ref2: 93 case DW_FORM_data2: 94 m_value.uval = data.GetU16(offset_ptr); 95 break; 96 case DW_FORM_addrx3: 97 case DW_FORM_strx3: 98 m_value.uval = data.GetMaxU64(offset_ptr, 3); 99 break; 100 case DW_FORM_addrx4: 101 case DW_FORM_strx4: 102 case DW_FORM_ref4: 103 case DW_FORM_data4: 104 m_value.uval = data.GetU32(offset_ptr); 105 break; 106 case DW_FORM_data8: 107 case DW_FORM_ref8: 108 case DW_FORM_ref_sig8: 109 m_value.uval = data.GetU64(offset_ptr); 110 break; 111 case DW_FORM_addrx: 112 case DW_FORM_loclistx: 113 case DW_FORM_rnglistx: 114 case DW_FORM_strx: 115 case DW_FORM_udata: 116 case DW_FORM_ref_udata: 117 case DW_FORM_GNU_str_index: 118 case DW_FORM_GNU_addr_index: 119 m_value.uval = data.GetULEB128(offset_ptr); 120 break; 121 case DW_FORM_ref_addr: 122 assert(m_unit); 123 m_value.uval = data.GetMaxU64( 124 offset_ptr, m_unit->GetFormParams().getRefAddrByteSize()); 125 break; 126 case DW_FORM_indirect: 127 m_form = static_cast<dw_form_t>(data.GetULEB128(offset_ptr)); 128 indirect = true; 129 break; 130 case DW_FORM_flag_present: 131 m_value.uval = 1; 132 break; 133 default: 134 return false; 135 } 136 } while (indirect); 137 138 if (is_block) { 139 m_value.data = data.PeekData(*offset_ptr, m_value.uval); 140 if (m_value.data != nullptr) { 141 *offset_ptr += m_value.uval; 142 } 143 } 144 145 return true; 146 } 147 148 struct FormSize { 149 uint8_t valid:1, size:7; 150 }; 151 static FormSize g_form_sizes[] = { 152 {0, 0}, // 0x00 unused 153 {0, 0}, // 0x01 DW_FORM_addr 154 {0, 0}, // 0x02 unused 155 {0, 0}, // 0x03 DW_FORM_block2 156 {0, 0}, // 0x04 DW_FORM_block4 157 {1, 2}, // 0x05 DW_FORM_data2 158 {1, 4}, // 0x06 DW_FORM_data4 159 {1, 8}, // 0x07 DW_FORM_data8 160 {0, 0}, // 0x08 DW_FORM_string 161 {0, 0}, // 0x09 DW_FORM_block 162 {0, 0}, // 0x0a DW_FORM_block1 163 {1, 1}, // 0x0b DW_FORM_data1 164 {1, 1}, // 0x0c DW_FORM_flag 165 {0, 0}, // 0x0d DW_FORM_sdata 166 {0, 0}, // 0x0e DW_FORM_strp (4 bytes for DWARF32, 8 bytes for DWARF64) 167 {0, 0}, // 0x0f DW_FORM_udata 168 {0, 0}, // 0x10 DW_FORM_ref_addr (addr size for DWARF2 and earlier, 4 bytes 169 // for DWARF32, 8 bytes for DWARF32 in DWARF 3 and later 170 {1, 1}, // 0x11 DW_FORM_ref1 171 {1, 2}, // 0x12 DW_FORM_ref2 172 {1, 4}, // 0x13 DW_FORM_ref4 173 {1, 8}, // 0x14 DW_FORM_ref8 174 {0, 0}, // 0x15 DW_FORM_ref_udata 175 {0, 0}, // 0x16 DW_FORM_indirect 176 {0, 0}, // 0x17 DW_FORM_sec_offset (4 bytes for DWARF32,8 bytes for DWARF64) 177 {0, 0}, // 0x18 DW_FORM_exprloc 178 {1, 0}, // 0x19 DW_FORM_flag_present 179 {0, 0}, // 0x1a DW_FORM_strx (ULEB128) 180 {0, 0}, // 0x1b DW_FORM_addrx (ULEB128) 181 {1, 4}, // 0x1c DW_FORM_ref_sup4 182 {0, 0}, // 0x1d DW_FORM_strp_sup (4 bytes for DWARF32, 8 bytes for DWARF64) 183 {1, 16}, // 0x1e DW_FORM_data16 184 {0, 0}, // 0x1f DW_FORM_line_strp (4 bytes for DWARF32, 8 bytes for DWARF64) 185 {1, 8}, // 0x20 DW_FORM_ref_sig8 186 }; 187 188 std::optional<uint8_t> DWARFFormValue::GetFixedSize(dw_form_t form, 189 const DWARFUnit *u) { 190 if (form <= DW_FORM_ref_sig8 && g_form_sizes[form].valid) 191 return static_cast<uint8_t>(g_form_sizes[form].size); 192 if (form == DW_FORM_addr && u) 193 return u->GetAddressByteSize(); 194 return std::nullopt; 195 } 196 197 std::optional<uint8_t> DWARFFormValue::GetFixedSize() const { 198 return GetFixedSize(m_form, m_unit); 199 } 200 201 bool DWARFFormValue::SkipValue(const DWARFDataExtractor &debug_info_data, 202 lldb::offset_t *offset_ptr) const { 203 return DWARFFormValue::SkipValue(m_form, debug_info_data, offset_ptr, m_unit); 204 } 205 206 bool DWARFFormValue::SkipValue(dw_form_t form, 207 const DWARFDataExtractor &debug_info_data, 208 lldb::offset_t *offset_ptr, 209 const DWARFUnit *unit) { 210 switch (form) { 211 // Blocks if inlined data that have a length field and the data bytes inlined 212 // in the .debug_info 213 case DW_FORM_exprloc: 214 case DW_FORM_block: { 215 uint64_t size = debug_info_data.GetULEB128(offset_ptr); 216 *offset_ptr += size; 217 } 218 return true; 219 case DW_FORM_block1: { 220 uint8_t size = debug_info_data.GetU8(offset_ptr); 221 *offset_ptr += size; 222 } 223 return true; 224 case DW_FORM_block2: { 225 uint16_t size = debug_info_data.GetU16(offset_ptr); 226 *offset_ptr += size; 227 } 228 return true; 229 case DW_FORM_block4: { 230 uint32_t size = debug_info_data.GetU32(offset_ptr); 231 *offset_ptr += size; 232 } 233 return true; 234 235 // Inlined NULL terminated C-strings 236 case DW_FORM_string: 237 debug_info_data.GetCStr(offset_ptr); 238 return true; 239 240 // Compile unit address sized values 241 case DW_FORM_addr: 242 *offset_ptr += DWARFUnit::GetAddressByteSize(unit); 243 return true; 244 245 case DW_FORM_ref_addr: 246 assert(unit); // Unit must be valid for DW_FORM_ref_addr objects or we will 247 // get this wrong 248 *offset_ptr += unit->GetFormParams().getRefAddrByteSize(); 249 return true; 250 251 // 0 bytes values (implied from DW_FORM) 252 case DW_FORM_flag_present: 253 case DW_FORM_implicit_const: 254 return true; 255 256 // 1 byte values 257 case DW_FORM_addrx1: 258 case DW_FORM_data1: 259 case DW_FORM_flag: 260 case DW_FORM_ref1: 261 case DW_FORM_strx1: 262 *offset_ptr += 1; 263 return true; 264 265 // 2 byte values 266 case DW_FORM_addrx2: 267 case DW_FORM_data2: 268 case DW_FORM_ref2: 269 case DW_FORM_strx2: 270 *offset_ptr += 2; 271 return true; 272 273 // 3 byte values 274 case DW_FORM_addrx3: 275 case DW_FORM_strx3: 276 *offset_ptr += 3; 277 return true; 278 279 // 32 bit for DWARF 32, 64 for DWARF 64 280 case DW_FORM_sec_offset: 281 case DW_FORM_strp: 282 case DW_FORM_line_strp: 283 assert(unit); 284 *offset_ptr += unit->GetFormParams().getDwarfOffsetByteSize(); 285 return true; 286 287 // 4 byte values 288 case DW_FORM_addrx4: 289 case DW_FORM_data4: 290 case DW_FORM_ref4: 291 case DW_FORM_strx4: 292 *offset_ptr += 4; 293 return true; 294 295 // 8 byte values 296 case DW_FORM_data8: 297 case DW_FORM_ref8: 298 case DW_FORM_ref_sig8: 299 *offset_ptr += 8; 300 return true; 301 302 // 16 byte values 303 case DW_FORM_data16: 304 *offset_ptr += 16; 305 return true; 306 307 // signed or unsigned LEB 128 values 308 case DW_FORM_addrx: 309 case DW_FORM_loclistx: 310 case DW_FORM_rnglistx: 311 case DW_FORM_sdata: 312 case DW_FORM_udata: 313 case DW_FORM_ref_udata: 314 case DW_FORM_GNU_addr_index: 315 case DW_FORM_GNU_str_index: 316 case DW_FORM_strx: 317 debug_info_data.Skip_LEB128(offset_ptr); 318 return true; 319 320 case DW_FORM_indirect: { 321 auto indirect_form = 322 static_cast<dw_form_t>(debug_info_data.GetULEB128(offset_ptr)); 323 return DWARFFormValue::SkipValue(indirect_form, debug_info_data, 324 offset_ptr, unit); 325 } 326 327 default: 328 break; 329 } 330 return false; 331 } 332 333 void DWARFFormValue::Dump(Stream &s) const { 334 uint64_t uvalue = Unsigned(); 335 bool unit_relative_offset = false; 336 337 switch (m_form) { 338 case DW_FORM_addr: 339 DumpAddress(s.AsRawOstream(), uvalue, sizeof(uint64_t)); 340 break; 341 case DW_FORM_flag: 342 case DW_FORM_data1: 343 s.PutHex8(uvalue); 344 break; 345 case DW_FORM_data2: 346 s.PutHex16(uvalue); 347 break; 348 case DW_FORM_sec_offset: 349 case DW_FORM_data4: 350 s.PutHex32(uvalue); 351 break; 352 case DW_FORM_ref_sig8: 353 case DW_FORM_data8: 354 s.PutHex64(uvalue); 355 break; 356 case DW_FORM_string: 357 s.QuotedCString(AsCString()); 358 break; 359 case DW_FORM_exprloc: 360 case DW_FORM_block: 361 case DW_FORM_block1: 362 case DW_FORM_block2: 363 case DW_FORM_block4: 364 if (uvalue > 0) { 365 switch (m_form) { 366 case DW_FORM_exprloc: 367 case DW_FORM_block: 368 s.Printf("<0x%" PRIx64 "> ", uvalue); 369 break; 370 case DW_FORM_block1: 371 s.Printf("<0x%2.2x> ", (uint8_t)uvalue); 372 break; 373 case DW_FORM_block2: 374 s.Printf("<0x%4.4x> ", (uint16_t)uvalue); 375 break; 376 case DW_FORM_block4: 377 s.Printf("<0x%8.8x> ", (uint32_t)uvalue); 378 break; 379 default: 380 break; 381 } 382 383 const uint8_t *data_ptr = m_value.data; 384 if (data_ptr) { 385 const uint8_t *end_data_ptr = 386 data_ptr + uvalue; // uvalue contains size of block 387 while (data_ptr < end_data_ptr) { 388 s.Printf("%2.2x ", *data_ptr); 389 ++data_ptr; 390 } 391 } else 392 s.PutCString("NULL"); 393 } 394 break; 395 396 case DW_FORM_sdata: 397 s.PutSLEB128(uvalue); 398 break; 399 case DW_FORM_udata: 400 s.PutULEB128(uvalue); 401 break; 402 case DW_FORM_strp: 403 case DW_FORM_line_strp: { 404 const char *dbg_str = AsCString(); 405 if (dbg_str) { 406 s.QuotedCString(dbg_str); 407 } else { 408 s.PutHex32(uvalue); 409 } 410 } break; 411 412 case DW_FORM_ref_addr: { 413 assert(m_unit); // Unit must be valid for DW_FORM_ref_addr objects or we 414 // will get this wrong 415 DumpAddress(s.AsRawOstream(), uvalue, 416 m_unit->GetFormParams().getRefAddrByteSize()); 417 break; 418 } 419 case DW_FORM_ref1: 420 unit_relative_offset = true; 421 break; 422 case DW_FORM_ref2: 423 unit_relative_offset = true; 424 break; 425 case DW_FORM_ref4: 426 unit_relative_offset = true; 427 break; 428 case DW_FORM_ref8: 429 unit_relative_offset = true; 430 break; 431 case DW_FORM_ref_udata: 432 unit_relative_offset = true; 433 break; 434 435 // All DW_FORM_indirect attributes should be resolved prior to calling this 436 // function 437 case DW_FORM_indirect: 438 s.PutCString("DW_FORM_indirect"); 439 break; 440 case DW_FORM_flag_present: 441 break; 442 default: 443 s.Printf("DW_FORM(0x%4.4x)", m_form); 444 break; 445 } 446 447 if (unit_relative_offset) { 448 assert(m_unit); // Unit must be valid for DW_FORM_ref forms that are compile 449 // unit relative or we will get this wrong 450 s.Printf("{0x%8.8" PRIx64 "}", uvalue + m_unit->GetOffset()); 451 } 452 } 453 454 const char *DWARFFormValue::AsCString() const { 455 DWARFContext &context = m_unit->GetSymbolFileDWARF().GetDWARFContext(); 456 457 if (m_form == DW_FORM_string) 458 return m_value.cstr; 459 if (m_form == DW_FORM_strp) 460 return context.getOrLoadStrData().PeekCStr(m_value.uval); 461 462 if (m_form == DW_FORM_GNU_str_index || m_form == DW_FORM_strx || 463 m_form == DW_FORM_strx1 || m_form == DW_FORM_strx2 || 464 m_form == DW_FORM_strx3 || m_form == DW_FORM_strx4) { 465 466 std::optional<uint64_t> offset = 467 m_unit->GetStringOffsetSectionItem(m_value.uval); 468 if (!offset) 469 return nullptr; 470 return context.getOrLoadStrData().PeekCStr(*offset); 471 } 472 473 if (m_form == DW_FORM_line_strp) 474 return context.getOrLoadLineStrData().PeekCStr(m_value.uval); 475 476 return nullptr; 477 } 478 479 dw_addr_t DWARFFormValue::Address() const { 480 SymbolFileDWARF &symbol_file = m_unit->GetSymbolFileDWARF(); 481 482 if (m_form == DW_FORM_addr) 483 return Unsigned(); 484 485 assert(m_unit); 486 assert(m_form == DW_FORM_GNU_addr_index || m_form == DW_FORM_addrx || 487 m_form == DW_FORM_addrx1 || m_form == DW_FORM_addrx2 || 488 m_form == DW_FORM_addrx3 || m_form == DW_FORM_addrx4); 489 490 uint32_t index_size = m_unit->GetAddressByteSize(); 491 dw_offset_t addr_base = m_unit->GetAddrBase(); 492 lldb::offset_t offset = addr_base + m_value.uval * index_size; 493 return symbol_file.GetDWARFContext().getOrLoadAddrData().GetMaxU64( 494 &offset, index_size); 495 } 496 497 std::pair<DWARFUnit *, uint64_t> 498 DWARFFormValue::ReferencedUnitAndOffset() const { 499 uint64_t value = m_value.uval; 500 switch (m_form) { 501 case DW_FORM_ref1: 502 case DW_FORM_ref2: 503 case DW_FORM_ref4: 504 case DW_FORM_ref8: 505 case DW_FORM_ref_udata: 506 assert(m_unit); // Unit must be valid for DW_FORM_ref forms that are compile 507 // unit relative or we will get this wrong 508 value += m_unit->GetOffset(); 509 if (!m_unit->ContainsDIEOffset(value)) { 510 m_unit->GetSymbolFileDWARF().GetObjectFile()->GetModule()->ReportError( 511 "DW_FORM_ref* DIE reference {0:x16} is outside of its CU", value); 512 return {nullptr, 0}; 513 } 514 return {const_cast<DWARFUnit *>(m_unit), value}; 515 516 case DW_FORM_ref_addr: { 517 DWARFUnit *ref_cu = 518 m_unit->GetSymbolFileDWARF().DebugInfo().GetUnitContainingDIEOffset( 519 DIERef::Section::DebugInfo, value); 520 if (!ref_cu) { 521 m_unit->GetSymbolFileDWARF().GetObjectFile()->GetModule()->ReportError( 522 "DW_FORM_ref_addr DIE reference {0:x16} has no matching CU", value); 523 return {nullptr, 0}; 524 } 525 return {ref_cu, value}; 526 } 527 528 case DW_FORM_ref_sig8: { 529 DWARFTypeUnit *tu = 530 m_unit->GetSymbolFileDWARF().DebugInfo().GetTypeUnitForHash(value); 531 if (!tu) 532 return {nullptr, 0}; 533 return {tu, tu->GetTypeOffset()}; 534 } 535 536 default: 537 return {nullptr, 0}; 538 } 539 } 540 541 DWARFDIE DWARFFormValue::Reference() const { 542 auto [unit, offset] = ReferencedUnitAndOffset(); 543 return unit ? unit->GetDIE(offset) : DWARFDIE(); 544 } 545 546 uint64_t DWARFFormValue::Reference(dw_offset_t base_offset) const { 547 uint64_t value = m_value.uval; 548 switch (m_form) { 549 case DW_FORM_ref1: 550 case DW_FORM_ref2: 551 case DW_FORM_ref4: 552 case DW_FORM_ref8: 553 case DW_FORM_ref_udata: 554 return value + base_offset; 555 556 case DW_FORM_ref_addr: 557 case DW_FORM_ref_sig8: 558 case DW_FORM_GNU_ref_alt: 559 return value; 560 561 default: 562 return DW_INVALID_OFFSET; 563 } 564 } 565 566 std::optional<uint64_t> DWARFFormValue::getAsUnsignedConstant() const { 567 if ((!IsDataForm(m_form)) || m_form == lldb_private::dwarf::DW_FORM_sdata) 568 return std::nullopt; 569 return m_value.uval; 570 } 571 572 std::optional<int64_t> DWARFFormValue::getAsSignedConstant() const { 573 if ((!IsDataForm(m_form)) || 574 (m_form == lldb_private::dwarf::DW_FORM_udata && 575 uint64_t(std::numeric_limits<int64_t>::max()) < m_value.uval)) 576 return std::nullopt; 577 switch (m_form) { 578 case lldb_private::dwarf::DW_FORM_data4: 579 return int32_t(m_value.uval); 580 case lldb_private::dwarf::DW_FORM_data2: 581 return int16_t(m_value.uval); 582 case lldb_private::dwarf::DW_FORM_data1: 583 return int8_t(m_value.uval); 584 case lldb_private::dwarf::DW_FORM_sdata: 585 case lldb_private::dwarf::DW_FORM_data8: 586 default: 587 return m_value.sval; 588 } 589 } 590 591 const uint8_t *DWARFFormValue::BlockData() const { return m_value.data; } 592 593 bool DWARFFormValue::IsBlockForm(const dw_form_t form) { 594 switch (form) { 595 case DW_FORM_exprloc: 596 case DW_FORM_block: 597 case DW_FORM_block1: 598 case DW_FORM_block2: 599 case DW_FORM_block4: 600 case DW_FORM_data16: 601 return true; 602 default: 603 return false; 604 } 605 llvm_unreachable("All cases handled above!"); 606 } 607 608 bool DWARFFormValue::IsDataForm(const dw_form_t form) { 609 switch (form) { 610 case DW_FORM_sdata: 611 case DW_FORM_udata: 612 case DW_FORM_data1: 613 case DW_FORM_data2: 614 case DW_FORM_data4: 615 case DW_FORM_data8: 616 return true; 617 default: 618 return false; 619 } 620 llvm_unreachable("All cases handled above!"); 621 } 622 623 bool DWARFFormValue::FormIsSupported(dw_form_t form) { 624 switch (form) { 625 case DW_FORM_addr: 626 case DW_FORM_addrx: 627 case DW_FORM_loclistx: 628 case DW_FORM_rnglistx: 629 case DW_FORM_block2: 630 case DW_FORM_block4: 631 case DW_FORM_data2: 632 case DW_FORM_data4: 633 case DW_FORM_data8: 634 case DW_FORM_data16: 635 case DW_FORM_string: 636 case DW_FORM_block: 637 case DW_FORM_block1: 638 case DW_FORM_data1: 639 case DW_FORM_flag: 640 case DW_FORM_sdata: 641 case DW_FORM_strp: 642 case DW_FORM_line_strp: 643 case DW_FORM_strx: 644 case DW_FORM_strx1: 645 case DW_FORM_strx2: 646 case DW_FORM_strx3: 647 case DW_FORM_strx4: 648 case DW_FORM_udata: 649 case DW_FORM_ref_addr: 650 case DW_FORM_ref1: 651 case DW_FORM_ref2: 652 case DW_FORM_ref4: 653 case DW_FORM_ref8: 654 case DW_FORM_ref_udata: 655 case DW_FORM_indirect: 656 case DW_FORM_sec_offset: 657 case DW_FORM_exprloc: 658 case DW_FORM_flag_present: 659 case DW_FORM_ref_sig8: 660 case DW_FORM_GNU_str_index: 661 case DW_FORM_GNU_addr_index: 662 case DW_FORM_implicit_const: 663 return true; 664 default: 665 break; 666 } 667 return false; 668 } 669