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 = dw_form_t(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 = static_cast<dw_form_t>(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 uint64_t size = debug_info_data.GetULEB128(offset_ptr); 220 *offset_ptr += size; 221 } 222 return true; 223 case DW_FORM_block1: { 224 uint8_t size = debug_info_data.GetU8(offset_ptr); 225 *offset_ptr += size; 226 } 227 return true; 228 case DW_FORM_block2: { 229 uint16_t size = debug_info_data.GetU16(offset_ptr); 230 *offset_ptr += size; 231 } 232 return true; 233 case DW_FORM_block4: { 234 uint32_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 auto indirect_form = 325 static_cast<dw_form_t>(debug_info_data.GetULEB128(offset_ptr)); 326 return DWARFFormValue::SkipValue(indirect_form, debug_info_data, 327 offset_ptr, unit); 328 } 329 330 default: 331 break; 332 } 333 return false; 334 } 335 336 void DWARFFormValue::Dump(Stream &s) const { 337 uint64_t uvalue = Unsigned(); 338 bool unit_relative_offset = false; 339 340 switch (m_form) { 341 case DW_FORM_addr: 342 DumpAddress(s.AsRawOstream(), uvalue, sizeof(uint64_t)); 343 break; 344 case DW_FORM_flag: 345 case DW_FORM_data1: 346 s.PutHex8(uvalue); 347 break; 348 case DW_FORM_data2: 349 s.PutHex16(uvalue); 350 break; 351 case DW_FORM_sec_offset: 352 case DW_FORM_data4: 353 s.PutHex32(uvalue); 354 break; 355 case DW_FORM_ref_sig8: 356 case DW_FORM_data8: 357 s.PutHex64(uvalue); 358 break; 359 case DW_FORM_string: 360 s.QuotedCString(AsCString()); 361 break; 362 case DW_FORM_exprloc: 363 case DW_FORM_block: 364 case DW_FORM_block1: 365 case DW_FORM_block2: 366 case DW_FORM_block4: 367 if (uvalue > 0) { 368 switch (m_form) { 369 case DW_FORM_exprloc: 370 case DW_FORM_block: 371 s.Printf("<0x%" PRIx64 "> ", uvalue); 372 break; 373 case DW_FORM_block1: 374 s.Printf("<0x%2.2x> ", (uint8_t)uvalue); 375 break; 376 case DW_FORM_block2: 377 s.Printf("<0x%4.4x> ", (uint16_t)uvalue); 378 break; 379 case DW_FORM_block4: 380 s.Printf("<0x%8.8x> ", (uint32_t)uvalue); 381 break; 382 default: 383 break; 384 } 385 386 const uint8_t *data_ptr = m_value.data; 387 if (data_ptr) { 388 const uint8_t *end_data_ptr = 389 data_ptr + uvalue; // uvalue contains size of block 390 while (data_ptr < end_data_ptr) { 391 s.Printf("%2.2x ", *data_ptr); 392 ++data_ptr; 393 } 394 } else 395 s.PutCString("NULL"); 396 } 397 break; 398 399 case DW_FORM_sdata: 400 s.PutSLEB128(uvalue); 401 break; 402 case DW_FORM_udata: 403 s.PutULEB128(uvalue); 404 break; 405 case DW_FORM_strp: 406 case DW_FORM_line_strp: { 407 const char *dbg_str = AsCString(); 408 if (dbg_str) { 409 s.QuotedCString(dbg_str); 410 } else { 411 s.PutHex32(uvalue); 412 } 413 } break; 414 415 case DW_FORM_ref_addr: { 416 assert(m_unit); // Unit must be valid for DW_FORM_ref_addr objects or we 417 // will get this wrong 418 if (m_unit->GetVersion() <= 2) 419 DumpAddress(s.AsRawOstream(), uvalue, sizeof(uint64_t) * 2); 420 else 421 DumpAddress(s.AsRawOstream(), uvalue, 422 4 * 2); // 4 for DWARF32, 8 for DWARF64, but we don't 423 // support DWARF64 yet 424 break; 425 } 426 case DW_FORM_ref1: 427 unit_relative_offset = true; 428 break; 429 case DW_FORM_ref2: 430 unit_relative_offset = true; 431 break; 432 case DW_FORM_ref4: 433 unit_relative_offset = true; 434 break; 435 case DW_FORM_ref8: 436 unit_relative_offset = true; 437 break; 438 case DW_FORM_ref_udata: 439 unit_relative_offset = true; 440 break; 441 442 // All DW_FORM_indirect attributes should be resolved prior to calling this 443 // function 444 case DW_FORM_indirect: 445 s.PutCString("DW_FORM_indirect"); 446 break; 447 case DW_FORM_flag_present: 448 break; 449 default: 450 s.Printf("DW_FORM(0x%4.4x)", m_form); 451 break; 452 } 453 454 if (unit_relative_offset) { 455 assert(m_unit); // Unit must be valid for DW_FORM_ref forms that are compile 456 // unit relative or we will get this wrong 457 s.Printf("{0x%8.8" PRIx64 "}", uvalue + m_unit->GetOffset()); 458 } 459 } 460 461 const char *DWARFFormValue::AsCString() const { 462 DWARFContext &context = m_unit->GetSymbolFileDWARF().GetDWARFContext(); 463 464 if (m_form == DW_FORM_string) 465 return m_value.value.cstr; 466 if (m_form == DW_FORM_strp) 467 return context.getOrLoadStrData().PeekCStr(m_value.value.uval); 468 469 if (m_form == DW_FORM_GNU_str_index || m_form == DW_FORM_strx || 470 m_form == DW_FORM_strx1 || m_form == DW_FORM_strx2 || 471 m_form == DW_FORM_strx3 || m_form == DW_FORM_strx4) { 472 473 std::optional<uint64_t> offset = 474 m_unit->GetStringOffsetSectionItem(m_value.value.uval); 475 if (!offset) 476 return nullptr; 477 return context.getOrLoadStrData().PeekCStr(*offset); 478 } 479 480 if (m_form == DW_FORM_line_strp) 481 return context.getOrLoadLineStrData().PeekCStr(m_value.value.uval); 482 483 return nullptr; 484 } 485 486 dw_addr_t DWARFFormValue::Address() const { 487 SymbolFileDWARF &symbol_file = m_unit->GetSymbolFileDWARF(); 488 489 if (m_form == DW_FORM_addr) 490 return Unsigned(); 491 492 assert(m_unit); 493 assert(m_form == DW_FORM_GNU_addr_index || m_form == DW_FORM_addrx || 494 m_form == DW_FORM_addrx1 || m_form == DW_FORM_addrx2 || 495 m_form == DW_FORM_addrx3 || m_form == DW_FORM_addrx4); 496 497 uint32_t index_size = m_unit->GetAddressByteSize(); 498 dw_offset_t addr_base = m_unit->GetAddrBase(); 499 lldb::offset_t offset = addr_base + m_value.value.uval * index_size; 500 return symbol_file.GetDWARFContext().getOrLoadAddrData().GetMaxU64( 501 &offset, index_size); 502 } 503 504 DWARFDIE DWARFFormValue::Reference() const { 505 uint64_t value = m_value.value.uval; 506 switch (m_form) { 507 case DW_FORM_ref1: 508 case DW_FORM_ref2: 509 case DW_FORM_ref4: 510 case DW_FORM_ref8: 511 case DW_FORM_ref_udata: 512 assert(m_unit); // Unit must be valid for DW_FORM_ref forms that are compile 513 // unit relative or we will get this wrong 514 value += m_unit->GetOffset(); 515 if (!m_unit->ContainsDIEOffset(value)) { 516 m_unit->GetSymbolFileDWARF().GetObjectFile()->GetModule()->ReportError( 517 "DW_FORM_ref* DIE reference {0:x16} is outside of its CU", value); 518 return {}; 519 } 520 return const_cast<DWARFUnit *>(m_unit)->GetDIE(value); 521 522 case DW_FORM_ref_addr: { 523 DWARFUnit *ref_cu = 524 m_unit->GetSymbolFileDWARF().DebugInfo().GetUnitContainingDIEOffset( 525 DIERef::Section::DebugInfo, value); 526 if (!ref_cu) { 527 m_unit->GetSymbolFileDWARF().GetObjectFile()->GetModule()->ReportError( 528 "DW_FORM_ref_addr DIE reference {0:x16} has no matching CU", value); 529 return {}; 530 } 531 return ref_cu->GetDIE(value); 532 } 533 534 case DW_FORM_ref_sig8: { 535 DWARFTypeUnit *tu = 536 m_unit->GetSymbolFileDWARF().DebugInfo().GetTypeUnitForHash(value); 537 if (!tu) 538 return {}; 539 return tu->GetDIE(tu->GetTypeOffset()); 540 } 541 542 default: 543 return {}; 544 } 545 } 546 547 uint64_t DWARFFormValue::Reference(dw_offset_t base_offset) const { 548 uint64_t value = m_value.value.uval; 549 switch (m_form) { 550 case DW_FORM_ref1: 551 case DW_FORM_ref2: 552 case DW_FORM_ref4: 553 case DW_FORM_ref8: 554 case DW_FORM_ref_udata: 555 return value + base_offset; 556 557 case DW_FORM_ref_addr: 558 case DW_FORM_ref_sig8: 559 case DW_FORM_GNU_ref_alt: 560 return value; 561 562 default: 563 return DW_INVALID_OFFSET; 564 } 565 } 566 567 const uint8_t *DWARFFormValue::BlockData() const { return m_value.data; } 568 569 bool DWARFFormValue::IsBlockForm(const dw_form_t form) { 570 switch (form) { 571 case DW_FORM_exprloc: 572 case DW_FORM_block: 573 case DW_FORM_block1: 574 case DW_FORM_block2: 575 case DW_FORM_block4: 576 return true; 577 default: 578 return false; 579 } 580 llvm_unreachable("All cases handled above!"); 581 } 582 583 bool DWARFFormValue::IsDataForm(const dw_form_t form) { 584 switch (form) { 585 case DW_FORM_sdata: 586 case DW_FORM_udata: 587 case DW_FORM_data1: 588 case DW_FORM_data2: 589 case DW_FORM_data4: 590 case DW_FORM_data8: 591 return true; 592 default: 593 return false; 594 } 595 llvm_unreachable("All cases handled above!"); 596 } 597 598 bool DWARFFormValue::FormIsSupported(dw_form_t form) { 599 switch (form) { 600 case DW_FORM_addr: 601 case DW_FORM_addrx: 602 case DW_FORM_loclistx: 603 case DW_FORM_rnglistx: 604 case DW_FORM_block2: 605 case DW_FORM_block4: 606 case DW_FORM_data2: 607 case DW_FORM_data4: 608 case DW_FORM_data8: 609 case DW_FORM_string: 610 case DW_FORM_block: 611 case DW_FORM_block1: 612 case DW_FORM_data1: 613 case DW_FORM_flag: 614 case DW_FORM_sdata: 615 case DW_FORM_strp: 616 case DW_FORM_line_strp: 617 case DW_FORM_strx: 618 case DW_FORM_strx1: 619 case DW_FORM_strx2: 620 case DW_FORM_strx3: 621 case DW_FORM_strx4: 622 case DW_FORM_udata: 623 case DW_FORM_ref_addr: 624 case DW_FORM_ref1: 625 case DW_FORM_ref2: 626 case DW_FORM_ref4: 627 case DW_FORM_ref8: 628 case DW_FORM_ref_udata: 629 case DW_FORM_indirect: 630 case DW_FORM_sec_offset: 631 case DW_FORM_exprloc: 632 case DW_FORM_flag_present: 633 case DW_FORM_ref_sig8: 634 case DW_FORM_GNU_str_index: 635 case DW_FORM_GNU_addr_index: 636 case DW_FORM_implicit_const: 637 return true; 638 default: 639 break; 640 } 641 return false; 642 } 643