1 //===--- ARMEHABIPrinter.h - ARM EHABI Unwind Information Printer ----------===// 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 #ifndef LLVM_TOOLS_LLVM_READOBJ_ARMEHABIPRINTER_H 10 #define LLVM_TOOLS_LLVM_READOBJ_ARMEHABIPRINTER_H 11 12 #include "llvm-readobj.h" 13 #include "llvm/ADT/STLExtras.h" 14 #include "llvm/Object/ELF.h" 15 #include "llvm/Object/ELFTypes.h" 16 #include "llvm/Support/ARMEHABI.h" 17 #include "llvm/Support/Debug.h" 18 #include "llvm/Support/Endian.h" 19 #include "llvm/Support/Format.h" 20 #include "llvm/Support/ScopedPrinter.h" 21 #include "llvm/Support/type_traits.h" 22 23 namespace llvm { 24 namespace ARM { 25 namespace EHABI { 26 27 class OpcodeDecoder { 28 ScopedPrinter &SW; 29 raw_ostream &OS; 30 31 struct RingEntry { 32 uint8_t Mask; 33 uint8_t Value; 34 void (OpcodeDecoder::*Routine)(const uint8_t *Opcodes, unsigned &OI); 35 }; 36 static ArrayRef<RingEntry> ring(); 37 38 void Decode_00xxxxxx(const uint8_t *Opcodes, unsigned &OI); 39 void Decode_01xxxxxx(const uint8_t *Opcodes, unsigned &OI); 40 void Decode_1000iiii_iiiiiiii(const uint8_t *Opcodes, unsigned &OI); 41 void Decode_10011101(const uint8_t *Opcodes, unsigned &OI); 42 void Decode_10011111(const uint8_t *Opcodes, unsigned &OI); 43 void Decode_1001nnnn(const uint8_t *Opcodes, unsigned &OI); 44 void Decode_10100nnn(const uint8_t *Opcodes, unsigned &OI); 45 void Decode_10101nnn(const uint8_t *Opcodes, unsigned &OI); 46 void Decode_10110000(const uint8_t *Opcodes, unsigned &OI); 47 void Decode_10110001_0000iiii(const uint8_t *Opcodes, unsigned &OI); 48 void Decode_10110010_uleb128(const uint8_t *Opcodes, unsigned &OI); 49 void Decode_10110011_sssscccc(const uint8_t *Opcodes, unsigned &OI); 50 void Decode_101101nn(const uint8_t *Opcodes, unsigned &OI); 51 void Decode_10111nnn(const uint8_t *Opcodes, unsigned &OI); 52 void Decode_11000110_sssscccc(const uint8_t *Opcodes, unsigned &OI); 53 void Decode_11000111_0000iiii(const uint8_t *Opcodes, unsigned &OI); 54 void Decode_11001000_sssscccc(const uint8_t *Opcodes, unsigned &OI); 55 void Decode_11001001_sssscccc(const uint8_t *Opcodes, unsigned &OI); 56 void Decode_11001yyy(const uint8_t *Opcodes, unsigned &OI); 57 void Decode_11000nnn(const uint8_t *Opcodes, unsigned &OI); 58 void Decode_11010nnn(const uint8_t *Opcodes, unsigned &OI); 59 void Decode_11xxxyyy(const uint8_t *Opcodes, unsigned &OI); 60 61 void PrintGPR(uint16_t GPRMask); 62 void PrintRegisters(uint32_t Mask, StringRef Prefix); 63 64 public: 65 OpcodeDecoder(ScopedPrinter &SW) : SW(SW), OS(SW.getOStream()) {} 66 void Decode(const uint8_t *Opcodes, off_t Offset, size_t Length); 67 }; 68 69 inline ArrayRef<OpcodeDecoder::RingEntry> OpcodeDecoder::ring() { 70 static const OpcodeDecoder::RingEntry Ring[] = { 71 {0xc0, 0x00, &OpcodeDecoder::Decode_00xxxxxx}, 72 {0xc0, 0x40, &OpcodeDecoder::Decode_01xxxxxx}, 73 {0xf0, 0x80, &OpcodeDecoder::Decode_1000iiii_iiiiiiii}, 74 {0xff, 0x9d, &OpcodeDecoder::Decode_10011101}, 75 {0xff, 0x9f, &OpcodeDecoder::Decode_10011111}, 76 {0xf0, 0x90, &OpcodeDecoder::Decode_1001nnnn}, 77 {0xf8, 0xa0, &OpcodeDecoder::Decode_10100nnn}, 78 {0xf8, 0xa8, &OpcodeDecoder::Decode_10101nnn}, 79 {0xff, 0xb0, &OpcodeDecoder::Decode_10110000}, 80 {0xff, 0xb1, &OpcodeDecoder::Decode_10110001_0000iiii}, 81 {0xff, 0xb2, &OpcodeDecoder::Decode_10110010_uleb128}, 82 {0xff, 0xb3, &OpcodeDecoder::Decode_10110011_sssscccc}, 83 {0xfc, 0xb4, &OpcodeDecoder::Decode_101101nn}, 84 {0xf8, 0xb8, &OpcodeDecoder::Decode_10111nnn}, 85 {0xff, 0xc6, &OpcodeDecoder::Decode_11000110_sssscccc}, 86 {0xff, 0xc7, &OpcodeDecoder::Decode_11000111_0000iiii}, 87 {0xff, 0xc8, &OpcodeDecoder::Decode_11001000_sssscccc}, 88 {0xff, 0xc9, &OpcodeDecoder::Decode_11001001_sssscccc}, 89 {0xc8, 0xc8, &OpcodeDecoder::Decode_11001yyy}, 90 {0xf8, 0xc0, &OpcodeDecoder::Decode_11000nnn}, 91 {0xf8, 0xd0, &OpcodeDecoder::Decode_11010nnn}, 92 {0xc0, 0xc0, &OpcodeDecoder::Decode_11xxxyyy}, 93 }; 94 return makeArrayRef(Ring); 95 } 96 97 inline void OpcodeDecoder::Decode_00xxxxxx(const uint8_t *Opcodes, 98 unsigned &OI) { 99 uint8_t Opcode = Opcodes[OI++ ^ 3]; 100 SW.startLine() << format("0x%02X ; vsp = vsp + %u\n", Opcode, 101 ((Opcode & 0x3f) << 2) + 4); 102 } 103 inline void OpcodeDecoder::Decode_01xxxxxx(const uint8_t *Opcodes, 104 unsigned &OI) { 105 uint8_t Opcode = Opcodes[OI++ ^ 3]; 106 SW.startLine() << format("0x%02X ; vsp = vsp - %u\n", Opcode, 107 ((Opcode & 0x3f) << 2) + 4); 108 } 109 inline void OpcodeDecoder::Decode_1000iiii_iiiiiiii(const uint8_t *Opcodes, 110 unsigned &OI) { 111 uint8_t Opcode0 = Opcodes[OI++ ^ 3]; 112 uint8_t Opcode1 = Opcodes[OI++ ^ 3]; 113 114 uint16_t GPRMask = (Opcode1 << 4) | ((Opcode0 & 0x0f) << 12); 115 SW.startLine() 116 << format("0x%02X 0x%02X ; %s", 117 Opcode0, Opcode1, GPRMask ? "pop " : "refuse to unwind"); 118 if (GPRMask) 119 PrintGPR(GPRMask); 120 OS << '\n'; 121 } 122 inline void OpcodeDecoder::Decode_10011101(const uint8_t *Opcodes, 123 unsigned &OI) { 124 uint8_t Opcode = Opcodes[OI++ ^ 3]; 125 SW.startLine() << format("0x%02X ; reserved (ARM MOVrr)\n", Opcode); 126 } 127 inline void OpcodeDecoder::Decode_10011111(const uint8_t *Opcodes, 128 unsigned &OI) { 129 uint8_t Opcode = Opcodes[OI++ ^ 3]; 130 SW.startLine() << format("0x%02X ; reserved (WiMMX MOVrr)\n", Opcode); 131 } 132 inline void OpcodeDecoder::Decode_1001nnnn(const uint8_t *Opcodes, 133 unsigned &OI) { 134 uint8_t Opcode = Opcodes[OI++ ^ 3]; 135 SW.startLine() << format("0x%02X ; vsp = r%u\n", Opcode, (Opcode & 0x0f)); 136 } 137 inline void OpcodeDecoder::Decode_10100nnn(const uint8_t *Opcodes, 138 unsigned &OI) { 139 uint8_t Opcode = Opcodes[OI++ ^ 3]; 140 SW.startLine() << format("0x%02X ; pop ", Opcode); 141 PrintGPR((((1 << ((Opcode & 0x7) + 1)) - 1) << 4)); 142 OS << '\n'; 143 } 144 inline void OpcodeDecoder::Decode_10101nnn(const uint8_t *Opcodes, 145 unsigned &OI) { 146 uint8_t Opcode = Opcodes[OI++ ^ 3]; 147 SW.startLine() << format("0x%02X ; pop ", Opcode); 148 PrintGPR((((1 << ((Opcode & 0x7) + 1)) - 1) << 4) | (1 << 14)); 149 OS << '\n'; 150 } 151 inline void OpcodeDecoder::Decode_10110000(const uint8_t *Opcodes, 152 unsigned &OI) { 153 uint8_t Opcode = Opcodes[OI++ ^ 3]; 154 SW.startLine() << format("0x%02X ; finish\n", Opcode); 155 } 156 inline void OpcodeDecoder::Decode_10110001_0000iiii(const uint8_t *Opcodes, 157 unsigned &OI) { 158 uint8_t Opcode0 = Opcodes[OI++ ^ 3]; 159 uint8_t Opcode1 = Opcodes[OI++ ^ 3]; 160 161 SW.startLine() 162 << format("0x%02X 0x%02X ; %s", Opcode0, Opcode1, 163 ((Opcode1 & 0xf0) || Opcode1 == 0x00) ? "spare" : "pop "); 164 if (((Opcode1 & 0xf0) == 0x00) && Opcode1) 165 PrintGPR((Opcode1 & 0x0f)); 166 OS << '\n'; 167 } 168 inline void OpcodeDecoder::Decode_10110010_uleb128(const uint8_t *Opcodes, 169 unsigned &OI) { 170 uint8_t Opcode = Opcodes[OI++ ^ 3]; 171 SW.startLine() << format("0x%02X ", Opcode); 172 173 SmallVector<uint8_t, 4> ULEB; 174 do { ULEB.push_back(Opcodes[OI ^ 3]); } while (Opcodes[OI++ ^ 3] & 0x80); 175 176 for (unsigned BI = 0, BE = ULEB.size(); BI != BE; ++BI) 177 OS << format("0x%02X ", ULEB[BI]); 178 179 uint64_t Value = 0; 180 for (unsigned BI = 0, BE = ULEB.size(); BI != BE; ++BI) 181 Value = Value | ((ULEB[BI] & 0x7f) << (7 * BI)); 182 183 OS << format("; vsp = vsp + %" PRIu64 "\n", 0x204 + (Value << 2)); 184 } 185 inline void OpcodeDecoder::Decode_10110011_sssscccc(const uint8_t *Opcodes, 186 unsigned &OI) { 187 uint8_t Opcode0 = Opcodes[OI++ ^ 3]; 188 uint8_t Opcode1 = Opcodes[OI++ ^ 3]; 189 SW.startLine() << format("0x%02X 0x%02X ; pop ", Opcode0, Opcode1); 190 uint8_t Start = ((Opcode1 & 0xf0) >> 4); 191 uint8_t Count = ((Opcode1 & 0x0f) >> 0); 192 PrintRegisters((((1 << (Count + 1)) - 1) << Start), "d"); 193 OS << '\n'; 194 } 195 inline void OpcodeDecoder::Decode_101101nn(const uint8_t *Opcodes, 196 unsigned &OI) { 197 uint8_t Opcode = Opcodes[OI++ ^ 3]; 198 SW.startLine() << format("0x%02X ; spare\n", Opcode); 199 } 200 inline void OpcodeDecoder::Decode_10111nnn(const uint8_t *Opcodes, 201 unsigned &OI) { 202 uint8_t Opcode = Opcodes[OI++ ^ 3]; 203 SW.startLine() << format("0x%02X ; pop ", Opcode); 204 PrintRegisters((((1 << ((Opcode & 0x07) + 1)) - 1) << 8), "d"); 205 OS << '\n'; 206 } 207 inline void OpcodeDecoder::Decode_11000110_sssscccc(const uint8_t *Opcodes, 208 unsigned &OI) { 209 uint8_t Opcode0 = Opcodes[OI++ ^ 3]; 210 uint8_t Opcode1 = Opcodes[OI++ ^ 3]; 211 SW.startLine() << format("0x%02X 0x%02X ; pop ", Opcode0, Opcode1); 212 uint8_t Start = ((Opcode1 & 0xf0) >> 4); 213 uint8_t Count = ((Opcode1 & 0x0f) >> 0); 214 PrintRegisters((((1 << (Count + 1)) - 1) << Start), "wR"); 215 OS << '\n'; 216 } 217 inline void OpcodeDecoder::Decode_11000111_0000iiii(const uint8_t *Opcodes, 218 unsigned &OI) { 219 uint8_t Opcode0 = Opcodes[OI++ ^ 3]; 220 uint8_t Opcode1 = Opcodes[OI++ ^ 3]; 221 SW.startLine() 222 << format("0x%02X 0x%02X ; %s", Opcode0, Opcode1, 223 ((Opcode1 & 0xf0) || Opcode1 == 0x00) ? "spare" : "pop "); 224 if ((Opcode1 & 0xf0) == 0x00 && Opcode1) 225 PrintRegisters(Opcode1 & 0x0f, "wCGR"); 226 OS << '\n'; 227 } 228 inline void OpcodeDecoder::Decode_11001000_sssscccc(const uint8_t *Opcodes, 229 unsigned &OI) { 230 uint8_t Opcode0 = Opcodes[OI++ ^ 3]; 231 uint8_t Opcode1 = Opcodes[OI++ ^ 3]; 232 SW.startLine() << format("0x%02X 0x%02X ; pop ", Opcode0, Opcode1); 233 uint8_t Start = 16 + ((Opcode1 & 0xf0) >> 4); 234 uint8_t Count = ((Opcode1 & 0x0f) >> 0); 235 PrintRegisters((((1 << (Count + 1)) - 1) << Start), "d"); 236 OS << '\n'; 237 } 238 inline void OpcodeDecoder::Decode_11001001_sssscccc(const uint8_t *Opcodes, 239 unsigned &OI) { 240 uint8_t Opcode0 = Opcodes[OI++ ^ 3]; 241 uint8_t Opcode1 = Opcodes[OI++ ^ 3]; 242 SW.startLine() << format("0x%02X 0x%02X ; pop ", Opcode0, Opcode1); 243 uint8_t Start = ((Opcode1 & 0xf0) >> 4); 244 uint8_t Count = ((Opcode1 & 0x0f) >> 0); 245 PrintRegisters((((1 << (Count + 1)) - 1) << Start), "d"); 246 OS << '\n'; 247 } 248 inline void OpcodeDecoder::Decode_11001yyy(const uint8_t *Opcodes, 249 unsigned &OI) { 250 uint8_t Opcode = Opcodes[OI++ ^ 3]; 251 SW.startLine() << format("0x%02X ; spare\n", Opcode); 252 } 253 inline void OpcodeDecoder::Decode_11000nnn(const uint8_t *Opcodes, 254 unsigned &OI) { 255 uint8_t Opcode = Opcodes[OI++ ^ 3]; 256 SW.startLine() << format("0x%02X ; pop ", Opcode); 257 PrintRegisters((((1 << ((Opcode & 0x07) + 1)) - 1) << 10), "wR"); 258 OS << '\n'; 259 } 260 inline void OpcodeDecoder::Decode_11010nnn(const uint8_t *Opcodes, 261 unsigned &OI) { 262 uint8_t Opcode = Opcodes[OI++ ^ 3]; 263 SW.startLine() << format("0x%02X ; pop ", Opcode); 264 PrintRegisters((((1 << ((Opcode & 0x07) + 1)) - 1) << 8), "d"); 265 OS << '\n'; 266 } 267 inline void OpcodeDecoder::Decode_11xxxyyy(const uint8_t *Opcodes, 268 unsigned &OI) { 269 uint8_t Opcode = Opcodes[OI++ ^ 3]; 270 SW.startLine() << format("0x%02X ; spare\n", Opcode); 271 } 272 273 inline void OpcodeDecoder::PrintGPR(uint16_t GPRMask) { 274 static const char *GPRRegisterNames[16] = { 275 "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7", "r8", "r9", "r10", 276 "fp", "ip", "sp", "lr", "pc" 277 }; 278 279 OS << '{'; 280 bool Comma = false; 281 for (unsigned RI = 0, RE = 17; RI < RE; ++RI) { 282 if (GPRMask & (1 << RI)) { 283 if (Comma) 284 OS << ", "; 285 OS << GPRRegisterNames[RI]; 286 Comma = true; 287 } 288 } 289 OS << '}'; 290 } 291 292 inline void OpcodeDecoder::PrintRegisters(uint32_t VFPMask, StringRef Prefix) { 293 OS << '{'; 294 bool Comma = false; 295 for (unsigned RI = 0, RE = 32; RI < RE; ++RI) { 296 if (VFPMask & (1 << RI)) { 297 if (Comma) 298 OS << ", "; 299 OS << Prefix << RI; 300 Comma = true; 301 } 302 } 303 OS << '}'; 304 } 305 306 inline void OpcodeDecoder::Decode(const uint8_t *Opcodes, off_t Offset, 307 size_t Length) { 308 for (unsigned OCI = Offset; OCI < Length + Offset; ) { 309 bool Decoded = false; 310 for (const auto &RE : ring()) { 311 if ((Opcodes[OCI ^ 3] & RE.Mask) == RE.Value) { 312 (this->*RE.Routine)(Opcodes, OCI); 313 Decoded = true; 314 break; 315 } 316 } 317 if (!Decoded) 318 SW.startLine() << format("0x%02X ; reserved\n", Opcodes[OCI++ ^ 3]); 319 } 320 } 321 322 template <typename ET> 323 class PrinterContext { 324 typedef typename ET::Sym Elf_Sym; 325 typedef typename ET::Shdr Elf_Shdr; 326 typedef typename ET::Rel Elf_Rel; 327 typedef typename ET::Word Elf_Word; 328 329 ScopedPrinter &SW; 330 const object::ELFFile<ET> &ELF; 331 StringRef FileName; 332 const Elf_Shdr *Symtab; 333 ArrayRef<Elf_Word> ShndxTable; 334 335 static const size_t IndexTableEntrySize; 336 337 static uint64_t PREL31(uint32_t Address, uint32_t Place) { 338 uint64_t Location = Address & 0x7fffffff; 339 if (Location & 0x40000000) 340 Location |= (uint64_t) ~0x7fffffff; 341 return Location + Place; 342 } 343 344 ErrorOr<StringRef> FunctionAtAddress(uint64_t Address, 345 Optional<unsigned> SectionIndex) const; 346 const Elf_Shdr *FindExceptionTable(unsigned IndexTableIndex, 347 off_t IndexTableOffset) const; 348 349 void PrintIndexTable(unsigned SectionIndex, const Elf_Shdr *IT) const; 350 void PrintExceptionTable(const Elf_Shdr &EHT, 351 uint64_t TableEntryOffset) const; 352 void PrintOpcodes(const uint8_t *Entry, size_t Length, off_t Offset) const; 353 354 public: 355 PrinterContext(ScopedPrinter &SW, const object::ELFFile<ET> &ELF, 356 StringRef FileName, const Elf_Shdr *Symtab) 357 : SW(SW), ELF(ELF), FileName(FileName), Symtab(Symtab) {} 358 359 void PrintUnwindInformation() const; 360 }; 361 362 template <typename ET> 363 const size_t PrinterContext<ET>::IndexTableEntrySize = 8; 364 365 template <typename ET> 366 ErrorOr<StringRef> 367 PrinterContext<ET>::FunctionAtAddress(uint64_t Address, 368 Optional<unsigned> SectionIndex) const { 369 if (!Symtab) 370 return inconvertibleErrorCode(); 371 auto StrTableOrErr = ELF.getStringTableForSymtab(*Symtab); 372 if (!StrTableOrErr) 373 reportError(StrTableOrErr.takeError(), FileName); 374 StringRef StrTable = *StrTableOrErr; 375 376 for (const Elf_Sym &Sym : unwrapOrError(FileName, ELF.symbols(Symtab))) { 377 if (SectionIndex && *SectionIndex != Sym.st_shndx) 378 continue; 379 380 if (Sym.st_value == Address && Sym.getType() == ELF::STT_FUNC) { 381 auto NameOrErr = Sym.getName(StrTable); 382 if (!NameOrErr) { 383 // TODO: Actually report errors helpfully. 384 consumeError(NameOrErr.takeError()); 385 return inconvertibleErrorCode(); 386 } 387 return *NameOrErr; 388 } 389 } 390 391 return inconvertibleErrorCode(); 392 } 393 394 template <typename ET> 395 const typename ET::Shdr * 396 PrinterContext<ET>::FindExceptionTable(unsigned IndexSectionIndex, 397 off_t IndexTableOffset) const { 398 /// Iterate through the sections, searching for the relocation section 399 /// associated with the unwind index table section specified by 400 /// IndexSectionIndex. Iterate the associated section searching for the 401 /// relocation associated with the index table entry specified by 402 /// IndexTableOffset. The symbol is the section symbol for the exception 403 /// handling table. Use this symbol to recover the actual exception handling 404 /// table. 405 406 for (const Elf_Shdr &Sec : unwrapOrError(FileName, ELF.sections())) { 407 if (Sec.sh_type != ELF::SHT_REL || Sec.sh_info != IndexSectionIndex) 408 continue; 409 410 auto SymTabOrErr = ELF.getSection(Sec.sh_link); 411 if (!SymTabOrErr) 412 reportError(SymTabOrErr.takeError(), FileName); 413 const Elf_Shdr *SymTab = *SymTabOrErr; 414 415 for (const Elf_Rel &R : unwrapOrError(FileName, ELF.rels(Sec))) { 416 if (R.r_offset != static_cast<unsigned>(IndexTableOffset)) 417 continue; 418 419 typename ET::Rela RelA; 420 RelA.r_offset = R.r_offset; 421 RelA.r_info = R.r_info; 422 RelA.r_addend = 0; 423 424 const Elf_Sym *Symbol = 425 unwrapOrError(FileName, ELF.getRelocationSymbol(RelA, SymTab)); 426 427 auto Ret = ELF.getSection(*Symbol, SymTab, ShndxTable); 428 if (!Ret) 429 report_fatal_error(errorToErrorCode(Ret.takeError()).message()); 430 return *Ret; 431 } 432 } 433 return nullptr; 434 } 435 436 template <typename ET> 437 static const typename ET::Shdr * 438 findSectionContainingAddress(const object::ELFFile<ET> &Obj, StringRef FileName, 439 uint64_t Address) { 440 for (const typename ET::Shdr &Sec : unwrapOrError(FileName, Obj.sections())) 441 if (Address >= Sec.sh_addr && Address < Sec.sh_addr + Sec.sh_size) 442 return &Sec; 443 return nullptr; 444 } 445 446 template <typename ET> 447 void PrinterContext<ET>::PrintExceptionTable(const Elf_Shdr &EHT, 448 uint64_t TableEntryOffset) const { 449 // TODO: handle failure. 450 Expected<ArrayRef<uint8_t>> Contents = ELF.getSectionContents(EHT); 451 if (!Contents) 452 return; 453 454 /// ARM EHABI Section 6.2 - The generic model 455 /// 456 /// An exception-handling table entry for the generic model is laid out as: 457 /// 458 /// 3 3 459 /// 1 0 0 460 /// +-+------------------------------+ 461 /// |0| personality routine offset | 462 /// +-+------------------------------+ 463 /// | personality routine data ... | 464 /// 465 /// 466 /// ARM EHABI Section 6.3 - The ARM-defined compact model 467 /// 468 /// An exception-handling table entry for the compact model looks like: 469 /// 470 /// 3 3 2 2 2 2 471 /// 1 0 8 7 4 3 0 472 /// +-+---+----+-----------------------+ 473 /// |1| 0 | Ix | data for pers routine | 474 /// +-+---+----+-----------------------+ 475 /// | more personality routine data | 476 477 const support::ulittle32_t Word = 478 *reinterpret_cast<const support::ulittle32_t *>(Contents->data() + TableEntryOffset); 479 480 if (Word & 0x80000000) { 481 SW.printString("Model", StringRef("Compact")); 482 483 unsigned PersonalityIndex = (Word & 0x0f000000) >> 24; 484 SW.printNumber("PersonalityIndex", PersonalityIndex); 485 486 switch (PersonalityIndex) { 487 case AEABI_UNWIND_CPP_PR0: 488 PrintOpcodes(Contents->data() + TableEntryOffset, 3, 1); 489 break; 490 case AEABI_UNWIND_CPP_PR1: 491 case AEABI_UNWIND_CPP_PR2: 492 unsigned AdditionalWords = (Word & 0x00ff0000) >> 16; 493 PrintOpcodes(Contents->data() + TableEntryOffset, 2 + 4 * AdditionalWords, 494 2); 495 break; 496 } 497 } else { 498 SW.printString("Model", StringRef("Generic")); 499 const bool IsRelocatable = ELF.getHeader().e_type == ELF::ET_REL; 500 uint64_t Address = IsRelocatable 501 ? PREL31(Word, EHT.sh_addr) 502 : PREL31(Word, EHT.sh_addr + TableEntryOffset); 503 SW.printHex("PersonalityRoutineAddress", Address); 504 Optional<unsigned> SecIndex = 505 IsRelocatable ? Optional<unsigned>(EHT.sh_link) : None; 506 if (ErrorOr<StringRef> Name = FunctionAtAddress(Address, SecIndex)) 507 SW.printString("PersonalityRoutineName", *Name); 508 } 509 } 510 511 template <typename ET> 512 void PrinterContext<ET>::PrintOpcodes(const uint8_t *Entry, 513 size_t Length, off_t Offset) const { 514 ListScope OCC(SW, "Opcodes"); 515 OpcodeDecoder(OCC.W).Decode(Entry, Offset, Length); 516 } 517 518 template <typename ET> 519 void PrinterContext<ET>::PrintIndexTable(unsigned SectionIndex, 520 const Elf_Shdr *IT) const { 521 // TODO: handle failure. 522 Expected<ArrayRef<uint8_t>> Contents = ELF.getSectionContents(*IT); 523 if (!Contents) 524 return; 525 526 /// ARM EHABI Section 5 - Index Table Entries 527 /// * The first word contains a PREL31 offset to the start of a function with 528 /// bit 31 clear 529 /// * The second word contains one of: 530 /// - The PREL31 offset of the start of the table entry for the function, 531 /// with bit 31 clear 532 /// - The exception-handling table entry itself with bit 31 set 533 /// - The special bit pattern EXIDX_CANTUNWIND, indicating that associated 534 /// frames cannot be unwound 535 536 const support::ulittle32_t *Data = 537 reinterpret_cast<const support::ulittle32_t *>(Contents->data()); 538 const unsigned Entries = IT->sh_size / IndexTableEntrySize; 539 const bool IsRelocatable = ELF.getHeader().e_type == ELF::ET_REL; 540 541 ListScope E(SW, "Entries"); 542 for (unsigned Entry = 0; Entry < Entries; ++Entry) { 543 DictScope E(SW, "Entry"); 544 545 const support::ulittle32_t Word0 = 546 Data[Entry * (IndexTableEntrySize / sizeof(*Data)) + 0]; 547 const support::ulittle32_t Word1 = 548 Data[Entry * (IndexTableEntrySize / sizeof(*Data)) + 1]; 549 550 if (Word0 & 0x80000000) { 551 errs() << "corrupt unwind data in section " << SectionIndex << "\n"; 552 continue; 553 } 554 555 // FIXME: For a relocatable object ideally we might want to: 556 // 1) Find a relocation for the offset of Word0. 557 // 2) Verify this relocation is of an expected type (R_ARM_PREL31) and 558 // verify the symbol index. 559 // 3) Resolve the relocation using it's symbol value, addend etc. 560 // Currently the code assumes that Word0 contains an addend of a 561 // R_ARM_PREL31 REL relocation that references a section symbol. RELA 562 // relocations are not supported and it works because addresses of sections 563 // are nulls in relocatable objects. 564 // 565 // For a non-relocatable object, Word0 contains a place-relative signed 566 // offset to the referenced entity. 567 const uint64_t Address = 568 IsRelocatable 569 ? PREL31(Word0, IT->sh_addr) 570 : PREL31(Word0, IT->sh_addr + Entry * IndexTableEntrySize); 571 SW.printHex("FunctionAddress", Address); 572 573 // In a relocatable output we might have many .ARM.exidx sections linked to 574 // their code sections via the sh_link field. For a non-relocatable ELF file 575 // the sh_link field is not reliable, because we have one .ARM.exidx section 576 // normally, but might have many code sections. 577 Optional<unsigned> SecIndex = 578 IsRelocatable ? Optional<unsigned>(IT->sh_link) : None; 579 if (ErrorOr<StringRef> Name = FunctionAtAddress(Address, SecIndex)) 580 SW.printString("FunctionName", *Name); 581 582 if (Word1 == EXIDX_CANTUNWIND) { 583 SW.printString("Model", StringRef("CantUnwind")); 584 continue; 585 } 586 587 if (Word1 & 0x80000000) { 588 SW.printString("Model", StringRef("Compact (Inline)")); 589 590 unsigned PersonalityIndex = (Word1 & 0x0f000000) >> 24; 591 SW.printNumber("PersonalityIndex", PersonalityIndex); 592 593 PrintOpcodes(Contents->data() + Entry * IndexTableEntrySize + 4, 3, 1); 594 } else { 595 const Elf_Shdr *EHT; 596 uint64_t TableEntryAddress; 597 if (IsRelocatable) { 598 TableEntryAddress = PREL31(Word1, IT->sh_addr); 599 EHT = FindExceptionTable(SectionIndex, Entry * IndexTableEntrySize + 4); 600 } else { 601 TableEntryAddress = 602 PREL31(Word1, IT->sh_addr + Entry * IndexTableEntrySize + 4); 603 EHT = findSectionContainingAddress(ELF, FileName, TableEntryAddress); 604 } 605 606 if (EHT) 607 // TODO: handle failure. 608 if (Expected<StringRef> Name = ELF.getSectionName(*EHT)) 609 SW.printString("ExceptionHandlingTable", *Name); 610 611 SW.printHex(IsRelocatable ? "TableEntryOffset" : "TableEntryAddress", 612 TableEntryAddress); 613 if (EHT) { 614 if (IsRelocatable) 615 PrintExceptionTable(*EHT, TableEntryAddress); 616 else 617 PrintExceptionTable(*EHT, TableEntryAddress - EHT->sh_addr); 618 } 619 } 620 } 621 } 622 623 template <typename ET> 624 void PrinterContext<ET>::PrintUnwindInformation() const { 625 DictScope UI(SW, "UnwindInformation"); 626 627 int SectionIndex = 0; 628 for (const Elf_Shdr &Sec : unwrapOrError(FileName, ELF.sections())) { 629 if (Sec.sh_type == ELF::SHT_ARM_EXIDX) { 630 DictScope UIT(SW, "UnwindIndexTable"); 631 632 SW.printNumber("SectionIndex", SectionIndex); 633 // TODO: handle failure. 634 if (Expected<StringRef> SectionName = ELF.getSectionName(Sec)) 635 SW.printString("SectionName", *SectionName); 636 SW.printHex("SectionOffset", Sec.sh_offset); 637 638 PrintIndexTable(SectionIndex, &Sec); 639 } 640 ++SectionIndex; 641 } 642 } 643 } 644 } 645 } 646 647 #endif 648
Indexes created Tue Sep 08 00:25:21 UTC 2026