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 class DWARFUnit; 22 23 using namespace lldb_private; 24 using namespace lldb_private::dwarf; 25 26 void DWARFFormValue::Clear() { 27 m_unit = nullptr; 28 m_form = 0; 29 m_value = ValueTypeTag(); 30 } 31 32 bool DWARFFormValue::ExtractValue(const DWARFDataExtractor &data, 33 lldb::offset_t *offset_ptr) { 34 if (m_form == DW_FORM_implicit_const) 35 return true; 36 37 bool indirect = false; 38 bool is_block = false; 39 m_value.data = nullptr; 40 uint8_t ref_addr_size; 41 // Read the value for the form into value and follow and DW_FORM_indirect 42 // instances we run into 43 do { 44 indirect = false; 45 switch (m_form) { 46 case DW_FORM_addr: 47 assert(m_unit); 48 m_value.value.uval = 49 data.GetMaxU64(offset_ptr, DWARFUnit::GetAddressByteSize(m_unit)); 50 break; 51 case DW_FORM_block1: 52 m_value.value.uval = data.GetU8(offset_ptr); 53 is_block = true; 54 break; 55 case DW_FORM_block2: 56 m_value.value.uval = data.GetU16(offset_ptr); 57 is_block = true; 58 break; 59 case DW_FORM_block4: 60 m_value.value.uval = data.GetU32(offset_ptr); 61 is_block = true; 62 break; 63 case DW_FORM_data16: 64 m_value.value.uval = 16; 65 is_block = true; 66 break; 67 case DW_FORM_exprloc: 68 case DW_FORM_block: 69 m_value.value.uval = data.GetULEB128(offset_ptr); 70 is_block = true; 71 break; 72 case DW_FORM_string: 73 m_value.value.cstr = data.GetCStr(offset_ptr); 74 break; 75 case DW_FORM_sdata: 76 m_value.value.sval = data.GetSLEB128(offset_ptr); 77 break; 78 case DW_FORM_strp: 79 case DW_FORM_line_strp: 80 case DW_FORM_sec_offset: 81 m_value.value.uval = data.GetMaxU64(offset_ptr, 4); 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.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.value.uval = data.GetU16(offset_ptr); 95 break; 96 case DW_FORM_addrx3: 97 case DW_FORM_strx3: 98 m_value.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.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.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.value.uval = data.GetULEB128(offset_ptr); 120 break; 121 case DW_FORM_ref_addr: 122 assert(m_unit); 123 if (m_unit->GetVersion() <= 2) 124 ref_addr_size = m_unit->GetAddressByteSize(); 125 else 126 ref_addr_size = 4; 127 m_value.value.uval = data.GetMaxU64(offset_ptr, ref_addr_size); 128 break; 129 case DW_FORM_indirect: 130 m_form = data.GetULEB128(offset_ptr); 131 indirect = true; 132 break; 133 case DW_FORM_flag_present: 134 m_value.value.uval = 1; 135 break; 136 default: 137 return false; 138 } 139 } while (indirect); 140 141 if (is_block) { 142 m_value.data = data.PeekData(*offset_ptr, m_value.value.uval); 143 if (m_value.data != nullptr) { 144 *offset_ptr += m_value.value.uval; 145 } 146 } 147 148 return true; 149 } 150 151 struct FormSize { 152 uint8_t valid:1, size:7; 153 }; 154 static FormSize g_form_sizes[] = { 155 {0, 0}, // 0x00 unused 156 {0, 0}, // 0x01 DW_FORM_addr 157 {0, 0}, // 0x02 unused 158 {0, 0}, // 0x03 DW_FORM_block2 159 {0, 0}, // 0x04 DW_FORM_block4 160 {1, 2}, // 0x05 DW_FORM_data2 161 {1, 4}, // 0x06 DW_FORM_data4 162 {1, 8}, // 0x07 DW_FORM_data8 163 {0, 0}, // 0x08 DW_FORM_string 164 {0, 0}, // 0x09 DW_FORM_block 165 {0, 0}, // 0x0a DW_FORM_block1 166 {1, 1}, // 0x0b DW_FORM_data1 167 {1, 1}, // 0x0c DW_FORM_flag 168 {0, 0}, // 0x0d DW_FORM_sdata 169 {1, 4}, // 0x0e DW_FORM_strp 170 {0, 0}, // 0x0f DW_FORM_udata 171 {0, 0}, // 0x10 DW_FORM_ref_addr (addr size for DWARF2 and earlier, 4 bytes 172 // for DWARF32, 8 bytes for DWARF32 in DWARF 3 and later 173 {1, 1}, // 0x11 DW_FORM_ref1 174 {1, 2}, // 0x12 DW_FORM_ref2 175 {1, 4}, // 0x13 DW_FORM_ref4 176 {1, 8}, // 0x14 DW_FORM_ref8 177 {0, 0}, // 0x15 DW_FORM_ref_udata 178 {0, 0}, // 0x16 DW_FORM_indirect 179 {1, 4}, // 0x17 DW_FORM_sec_offset 180 {0, 0}, // 0x18 DW_FORM_exprloc 181 {1, 0}, // 0x19 DW_FORM_flag_present 182 {0, 0}, // 0x1a DW_FORM_strx (ULEB128) 183 {0, 0}, // 0x1b DW_FORM_addrx (ULEB128) 184 {1, 4}, // 0x1c DW_FORM_ref_sup4 185 {0, 0}, // 0x1d DW_FORM_strp_sup (4 bytes for DWARF32, 8 bytes for DWARF64) 186 {1, 16}, // 0x1e DW_FORM_data16 187 {1, 4}, // 0x1f DW_FORM_line_strp 188 {1, 8}, // 0x20 DW_FORM_ref_sig8 189 }; 190 191 std::optional<uint8_t> DWARFFormValue::GetFixedSize(dw_form_t form, 192 const DWARFUnit *u) { 193 if (form <= DW_FORM_ref_sig8 && g_form_sizes[form].valid) 194 return static_cast<uint8_t>(g_form_sizes[form].size); 195 if (form == DW_FORM_addr && u) 196 return u->GetAddressByteSize(); 197 return std::nullopt; 198 } 199 200 std::optional<uint8_t> DWARFFormValue::GetFixedSize() const { 201 return GetFixedSize(m_form, m_unit); 202 } 203 204 bool DWARFFormValue::SkipValue(const DWARFDataExtractor &debug_info_data, 205 lldb::offset_t *offset_ptr) const { 206 return DWARFFormValue::SkipValue(m_form, debug_info_data, offset_ptr, m_unit); 207 } 208 209 bool DWARFFormValue::SkipValue(dw_form_t form, 210 const DWARFDataExtractor &debug_info_data, 211 lldb::offset_t *offset_ptr, 212 const DWARFUnit *unit) { 213 uint8_t ref_addr_size; 214 switch (form) { 215 // Blocks if inlined data that have a length field and the data bytes inlined 216 // in the .debug_info 217 case DW_FORM_exprloc: 218 case DW_FORM_block: { 219 dw_uleb128_t size = debug_info_data.GetULEB128(offset_ptr); 220 *offset_ptr += size; 221 } 222 return true; 223 case DW_FORM_block1: { 224 dw_uleb128_t size = debug_info_data.GetU8(offset_ptr); 225 *offset_ptr += size; 226 } 227 return true; 228 case DW_FORM_block2: { 229 dw_uleb128_t size = debug_info_data.GetU16(offset_ptr); 230 *offset_ptr += size; 231 } 232 return true; 233 case DW_FORM_block4: { 234 dw_uleb128_t size = debug_info_data.GetU32(offset_ptr); 235 *offset_ptr += size; 236 } 237 return true; 238 239 // Inlined NULL terminated C-strings 240 case DW_FORM_string: 241 debug_info_data.GetCStr(offset_ptr); 242 return true; 243 244 // Compile unit address sized values 245 case DW_FORM_addr: 246 *offset_ptr += DWARFUnit::GetAddressByteSize(unit); 247 return true; 248 249 case DW_FORM_ref_addr: 250 ref_addr_size = 4; 251 assert(unit); // Unit must be valid for DW_FORM_ref_addr objects or we will 252 // get this wrong 253 if (unit->GetVersion() <= 2) 254 ref_addr_size = unit->GetAddressByteSize(); 255 else 256 ref_addr_size = 4; 257 *offset_ptr += ref_addr_size; 258 return true; 259 260 // 0 bytes values (implied from DW_FORM) 261 case DW_FORM_flag_present: 262 case DW_FORM_implicit_const: 263 return true; 264 265 // 1 byte values 266 case DW_FORM_addrx1: 267 case DW_FORM_data1: 268 case DW_FORM_flag: 269 case DW_FORM_ref1: 270 case DW_FORM_strx1: 271 *offset_ptr += 1; 272 return true; 273 274 // 2 byte values 275 case DW_FORM_addrx2: 276 case DW_FORM_data2: 277 case DW_FORM_ref2: 278 case DW_FORM_strx2: 279 *offset_ptr += 2; 280 return true; 281 282 // 3 byte values 283 case DW_FORM_addrx3: 284 case DW_FORM_strx3: 285 *offset_ptr += 3; 286 return true; 287 288 // 32 bit for DWARF 32, 64 for DWARF 64 289 case DW_FORM_sec_offset: 290 case DW_FORM_strp: 291 case DW_FORM_line_strp: 292 *offset_ptr += 4; 293 return true; 294 295 // 4 byte values 296 case DW_FORM_addrx4: 297 case DW_FORM_data4: 298 case DW_FORM_ref4: 299 case DW_FORM_strx4: 300 *offset_ptr += 4; 301 return true; 302 303 // 8 byte values 304 case DW_FORM_data8: 305 case DW_FORM_ref8: 306 case DW_FORM_ref_sig8: 307 *offset_ptr += 8; 308 return true; 309 310 // signed or unsigned LEB 128 values 311 case DW_FORM_addrx: 312 case DW_FORM_loclistx: 313 case DW_FORM_rnglistx: 314 case DW_FORM_sdata: 315 case DW_FORM_udata: 316 case DW_FORM_ref_udata: 317 case DW_FORM_GNU_addr_index: 318 case DW_FORM_GNU_str_index: 319 case DW_FORM_strx: 320 debug_info_data.Skip_LEB128(offset_ptr); 321 return true; 322 323 case DW_FORM_indirect: { 324 dw_form_t indirect_form = debug_info_data.GetULEB128(offset_ptr); 325 return DWARFFormValue::SkipValue(indirect_form, debug_info_data, offset_ptr, 326 unit); 327 } 328 329 default: 330 break; 331 } 332 return false; 333 } 334 335 void DWARFFormValue::Dump(Stream &s) const { 336 uint64_t uvalue = Unsigned(); 337 bool unit_relative_offset = false; 338 339 switch (m_form) { 340 case DW_FORM_addr: 341 DumpAddress(s.AsRawOstream(), uvalue, sizeof(uint64_t)); 342 break; 343 case DW_FORM_flag: 344 case DW_FORM_data1: 345 s.PutHex8(uvalue); 346 break; 347 case DW_FORM_data2: 348 s.PutHex16(uvalue); 349 break; 350 case DW_FORM_sec_offset: 351 case DW_FORM_data4: 352 s.PutHex32(uvalue); 353 break; 354 case DW_FORM_ref_sig8: 355 case DW_FORM_data8: 356 s.PutHex64(uvalue); 357 break; 358 case DW_FORM_string: 359 s.QuotedCString(AsCString()); 360 break; 361 case DW_FORM_exprloc: 362 case DW_FORM_block: 363 case DW_FORM_block1: 364 case DW_FORM_block2: 365 case DW_FORM_block4: 366 if (uvalue > 0) { 367 switch (m_form) { 368 case DW_FORM_exprloc: 369 case DW_FORM_block: 370 s.Printf("<0x%" PRIx64 "> ", uvalue); 371 break; 372 case DW_FORM_block1: 373 s.Printf("<0x%2.2x> ", (uint8_t)uvalue); 374 break; 375 case DW_FORM_block2: 376 s.Printf("<0x%4.4x> ", (uint16_t)uvalue); 377 break; 378 case DW_FORM_block4: 379 s.Printf("<0x%8.8x> ", (uint32_t)uvalue); 380 break; 381 default: 382 break; 383 } 384 385 const uint8_t *data_ptr = m_value.data; 386 if (data_ptr) { 387 const uint8_t *end_data_ptr = 388 data_ptr + uvalue; // uvalue contains size of block 389 while (data_ptr < end_data_ptr) { 390 s.Printf("%2.2x ", *data_ptr); 391 ++data_ptr; 392 } 393 } else 394 s.PutCString("NULL"); 395 } 396 break; 397 398 case DW_FORM_sdata: 399 s.PutSLEB128(uvalue); 400 break; 401 case DW_FORM_udata: 402 s.PutULEB128(uvalue); 403 break; 404 case DW_FORM_strp: 405 case DW_FORM_line_strp: { 406 const char *dbg_str = AsCString(); 407 if (dbg_str) { 408 s.QuotedCString(dbg_str); 409 } else { 410 s.PutHex32(uvalue); 411 } 412 } break; 413 414 case DW_FORM_ref_addr: { 415 assert(m_unit); // Unit must be valid for DW_FORM_ref_addr objects or we 416 // will get this wrong 417 if (m_unit->GetVersion() <= 2) 418 DumpAddress(s.AsRawOstream(), uvalue, sizeof(uint64_t) * 2); 419 else 420 DumpAddress(s.AsRawOstream(), uvalue, 421 4 * 2); // 4 for DWARF32, 8 for DWARF64, but we don't 422 // support DWARF64 yet 423 break; 424 } 425 case DW_FORM_ref1: 426 unit_relative_offset = true; 427 break; 428 case DW_FORM_ref2: 429 unit_relative_offset = true; 430 break; 431 case DW_FORM_ref4: 432 unit_relative_offset = true; 433 break; 434 case DW_FORM_ref8: 435 unit_relative_offset = true; 436 break; 437 case DW_FORM_ref_udata: 438 unit_relative_offset = true; 439 break; 440 441 // All DW_FORM_indirect attributes should be resolved prior to calling this 442 // function 443 case DW_FORM_indirect: 444 s.PutCString("DW_FORM_indirect"); 445 break; 446 case DW_FORM_flag_present: 447 break; 448 default: 449 s.Printf("DW_FORM(0x%4.4x)", m_form); 450 break; 451 } 452 453 if (unit_relative_offset) { 454 assert(m_unit); // Unit must be valid for DW_FORM_ref forms that are compile 455 // unit relative or we will get this wrong 456 s.Printf("{0x%8.8" PRIx64 "}", uvalue + m_unit->GetOffset()); 457 } 458 } 459 460 const char *DWARFFormValue::AsCString() const { 461 DWARFContext &context = m_unit->GetSymbolFileDWARF().GetDWARFContext(); 462 463 if (m_form == DW_FORM_string) 464 return m_value.value.cstr; 465 if (m_form == DW_FORM_strp) 466 return context.getOrLoadStrData().PeekCStr(m_value.value.uval); 467 468 if (m_form == DW_FORM_GNU_str_index || m_form == DW_FORM_strx || 469 m_form == DW_FORM_strx1 || m_form == DW_FORM_strx2 || 470 m_form == DW_FORM_strx3 || m_form == DW_FORM_strx4) { 471 472 std::optional<uint64_t> offset = 473 m_unit->GetStringOffsetSectionItem(m_value.value.uval); 474 if (!offset) 475 return nullptr; 476 return context.getOrLoadStrData().PeekCStr(*offset); 477 } 478 479 if (m_form == DW_FORM_line_strp) 480 return context.getOrLoadLineStrData().PeekCStr(m_value.value.uval); 481 482 return nullptr; 483 } 484 485 dw_addr_t DWARFFormValue::Address() const { 486 SymbolFileDWARF &symbol_file = m_unit->GetSymbolFileDWARF(); 487 488 if (m_form == DW_FORM_addr) 489 return Unsigned(); 490 491 assert(m_unit); 492 assert(m_form == DW_FORM_GNU_addr_index || m_form == DW_FORM_addrx || 493 m_form == DW_FORM_addrx1 || m_form == DW_FORM_addrx2 || 494 m_form == DW_FORM_addrx3 || m_form == DW_FORM_addrx4); 495 496 uint32_t index_size = m_unit->GetAddressByteSize(); 497 dw_offset_t addr_base = m_unit->GetAddrBase(); 498 lldb::offset_t offset = addr_base + m_value.value.uval * index_size; 499 return symbol_file.GetDWARFContext().getOrLoadAddrData().GetMaxU64( 500 &offset, index_size); 501 } 502 503 DWARFDIE DWARFFormValue::Reference() const { 504 uint64_t value = m_value.value.uval; 505 switch (m_form) { 506 case DW_FORM_ref1: 507 case DW_FORM_ref2: 508 case DW_FORM_ref4: 509 case DW_FORM_ref8: 510 case DW_FORM_ref_udata: 511 assert(m_unit); // Unit must be valid for DW_FORM_ref forms that are compile 512 // unit relative or we will get this wrong 513 value += m_unit->GetOffset(); 514 if (!m_unit->ContainsDIEOffset(value)) { 515 m_unit->GetSymbolFileDWARF().GetObjectFile()->GetModule()->ReportError( 516 "DW_FORM_ref* DIE reference {0:x16} is outside of its CU", value); 517 return {}; 518 } 519 return const_cast<DWARFUnit *>(m_unit)->GetDIE(value); 520 521 case DW_FORM_ref_addr: { 522 DWARFUnit *ref_cu = 523 m_unit->GetSymbolFileDWARF().DebugInfo().GetUnitContainingDIEOffset( 524 DIERef::Section::DebugInfo, value); 525 if (!ref_cu) { 526 m_unit->GetSymbolFileDWARF().GetObjectFile()->GetModule()->ReportError( 527 "DW_FORM_ref_addr DIE reference {0:x16} has no matching CU", value); 528 return {}; 529 } 530 return ref_cu->GetDIE(value); 531 } 532 533 case DW_FORM_ref_sig8: { 534 DWARFTypeUnit *tu = 535 m_unit->GetSymbolFileDWARF().DebugInfo().GetTypeUnitForHash(value); 536 if (!tu) 537 return {}; 538 return tu->GetDIE(tu->GetTypeOffset()); 539 } 540 541 default: 542 return {}; 543 } 544 } 545 546 uint64_t DWARFFormValue::Reference(dw_offset_t base_offset) const { 547 uint64_t value = m_value.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 const uint8_t *DWARFFormValue::BlockData() const { return m_value.data; } 567 568 bool DWARFFormValue::IsBlockForm(const dw_form_t form) { 569 switch (form) { 570 case DW_FORM_exprloc: 571 case DW_FORM_block: 572 case DW_FORM_block1: 573 case DW_FORM_block2: 574 case DW_FORM_block4: 575 return true; 576 } 577 return false; 578 } 579 580 bool DWARFFormValue::IsDataForm(const dw_form_t form) { 581 switch (form) { 582 case DW_FORM_sdata: 583 case DW_FORM_udata: 584 case DW_FORM_data1: 585 case DW_FORM_data2: 586 case DW_FORM_data4: 587 case DW_FORM_data8: 588 return true; 589 } 590 return false; 591 } 592 593 bool DWARFFormValue::FormIsSupported(dw_form_t form) { 594 switch (form) { 595 case DW_FORM_addr: 596 case DW_FORM_addrx: 597 case DW_FORM_loclistx: 598 case DW_FORM_rnglistx: 599 case DW_FORM_block2: 600 case DW_FORM_block4: 601 case DW_FORM_data2: 602 case DW_FORM_data4: 603 case DW_FORM_data8: 604 case DW_FORM_string: 605 case DW_FORM_block: 606 case DW_FORM_block1: 607 case DW_FORM_data1: 608 case DW_FORM_flag: 609 case DW_FORM_sdata: 610 case DW_FORM_strp: 611 case DW_FORM_line_strp: 612 case DW_FORM_strx: 613 case DW_FORM_strx1: 614 case DW_FORM_strx2: 615 case DW_FORM_strx3: 616 case DW_FORM_strx4: 617 case DW_FORM_udata: 618 case DW_FORM_ref_addr: 619 case DW_FORM_ref1: 620 case DW_FORM_ref2: 621 case DW_FORM_ref4: 622 case DW_FORM_ref8: 623 case DW_FORM_ref_udata: 624 case DW_FORM_indirect: 625 case DW_FORM_sec_offset: 626 case DW_FORM_exprloc: 627 case DW_FORM_flag_present: 628 case DW_FORM_ref_sig8: 629 case DW_FORM_GNU_str_index: 630 case DW_FORM_GNU_addr_index: 631 case DW_FORM_implicit_const: 632 return true; 633 default: 634 break; 635 } 636 return false; 637 } 638