1 //===- Win64EHDumper.cpp - Win64 EH Printer ---------------------*- C++ -*-===// 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 "Win64EHDumper.h" 10 #include "llvm-readobj.h" 11 #include "llvm/Object/COFF.h" 12 #include "llvm/Support/ErrorHandling.h" 13 #include "llvm/Support/Format.h" 14 15 using namespace llvm; 16 using namespace llvm::object; 17 using namespace llvm::Win64EH; 18 19 const EnumEntry<unsigned> UnwindFlags[] = { 20 { "ExceptionHandler", UNW_ExceptionHandler }, 21 { "TerminateHandler", UNW_TerminateHandler }, 22 { "ChainInfo" , UNW_ChainInfo } 23 }; 24 25 const EnumEntry<unsigned> UnwindOpInfo[] = { 26 { "RAX", 0 }, 27 { "RCX", 1 }, 28 { "RDX", 2 }, 29 { "RBX", 3 }, 30 { "RSP", 4 }, 31 { "RBP", 5 }, 32 { "RSI", 6 }, 33 { "RDI", 7 }, 34 { "R8", 8 }, 35 { "R9", 9 }, 36 { "R10", 10 }, 37 { "R11", 11 }, 38 { "R12", 12 }, 39 { "R13", 13 }, 40 { "R14", 14 }, 41 { "R15", 15 } 42 }; 43 44 static uint64_t getOffsetOfLSDA(const UnwindInfo& UI) { 45 return static_cast<const char*>(UI.getLanguageSpecificData()) 46 - reinterpret_cast<const char*>(&UI); 47 } 48 49 static uint32_t getLargeSlotValue(ArrayRef<UnwindCode> UC) { 50 if (UC.size() < 3) 51 return 0; 52 return UC[1].FrameOffset + (static_cast<uint32_t>(UC[2].FrameOffset) << 16); 53 } 54 55 // Returns the name of the unwind code. 56 static StringRef getUnwindCodeTypeName(uint8_t Code) { 57 switch (Code) { 58 default: llvm_unreachable("Invalid unwind code"); 59 case UOP_PushNonVol: return "PUSH_NONVOL"; 60 case UOP_AllocLarge: return "ALLOC_LARGE"; 61 case UOP_AllocSmall: return "ALLOC_SMALL"; 62 case UOP_SetFPReg: return "SET_FPREG"; 63 case UOP_SaveNonVol: return "SAVE_NONVOL"; 64 case UOP_SaveNonVolBig: return "SAVE_NONVOL_FAR"; 65 case UOP_SaveXMM128: return "SAVE_XMM128"; 66 case UOP_SaveXMM128Big: return "SAVE_XMM128_FAR"; 67 case UOP_PushMachFrame: return "PUSH_MACHFRAME"; 68 } 69 } 70 71 // Returns the name of a referenced register. 72 static StringRef getUnwindRegisterName(uint8_t Reg) { 73 switch (Reg) { 74 default: llvm_unreachable("Invalid register"); 75 case 0: return "RAX"; 76 case 1: return "RCX"; 77 case 2: return "RDX"; 78 case 3: return "RBX"; 79 case 4: return "RSP"; 80 case 5: return "RBP"; 81 case 6: return "RSI"; 82 case 7: return "RDI"; 83 case 8: return "R8"; 84 case 9: return "R9"; 85 case 10: return "R10"; 86 case 11: return "R11"; 87 case 12: return "R12"; 88 case 13: return "R13"; 89 case 14: return "R14"; 90 case 15: return "R15"; 91 } 92 } 93 94 // Calculates the number of array slots required for the unwind code. 95 static unsigned getNumUsedSlots(const UnwindCode &UnwindCode) { 96 switch (UnwindCode.getUnwindOp()) { 97 default: llvm_unreachable("Invalid unwind code"); 98 case UOP_PushNonVol: 99 case UOP_AllocSmall: 100 case UOP_SetFPReg: 101 case UOP_PushMachFrame: 102 return 1; 103 case UOP_SaveNonVol: 104 case UOP_SaveXMM128: 105 return 2; 106 case UOP_SaveNonVolBig: 107 case UOP_SaveXMM128Big: 108 return 3; 109 case UOP_AllocLarge: 110 return (UnwindCode.getOpInfo() == 0) ? 2 : 3; 111 } 112 } 113 114 static std::error_code getSymbol(const COFFObjectFile &COFF, uint64_t VA, 115 object::SymbolRef &Sym) { 116 for (const auto &Symbol : COFF.symbols()) { 117 Expected<uint64_t> Address = Symbol.getAddress(); 118 if (!Address) 119 return errorToErrorCode(Address.takeError()); 120 if (*Address == VA) { 121 Sym = Symbol; 122 return std::error_code(); 123 } 124 } 125 return inconvertibleErrorCode(); 126 } 127 128 static object::SymbolRef getPreferredSymbol(const COFFObjectFile &COFF, 129 object::SymbolRef Sym, 130 uint32_t &SymbolOffset, 131 bool IsRangeEnd) { 132 // The symbol resolved by ResolveSymbol can be any internal 133 // nondescriptive symbol; try to resolve a more descriptive one. 134 COFFSymbolRef CoffSym = COFF.getCOFFSymbol(Sym); 135 if (CoffSym.getStorageClass() != COFF::IMAGE_SYM_CLASS_LABEL && 136 CoffSym.getSectionDefinition() == nullptr) 137 return Sym; 138 for (const auto &S : COFF.symbols()) { 139 COFFSymbolRef CS = COFF.getCOFFSymbol(S); 140 if (CS.getSectionNumber() == CoffSym.getSectionNumber() && 141 CS.getValue() <= CoffSym.getValue() + SymbolOffset && 142 CS.getStorageClass() != COFF::IMAGE_SYM_CLASS_LABEL && 143 CS.getSectionDefinition() == nullptr) { 144 uint32_t Offset = CoffSym.getValue() + SymbolOffset - CS.getValue(); 145 // For the end of a range, don't pick a symbol with a zero offset; 146 // prefer a symbol with a small positive offset. 147 if (Offset <= SymbolOffset && (!IsRangeEnd || Offset > 0)) { 148 SymbolOffset = Offset; 149 Sym = S; 150 CoffSym = CS; 151 if (CS.isExternal() && SymbolOffset == 0) 152 return Sym; 153 } 154 } 155 } 156 return Sym; 157 } 158 159 static std::string formatSymbol(const Dumper::Context &Ctx, 160 const coff_section *Section, uint64_t Offset, 161 uint32_t Displacement, 162 bool IsRangeEnd = false) { 163 std::string Buffer; 164 raw_string_ostream OS(Buffer); 165 166 SymbolRef Symbol; 167 if (!Ctx.ResolveSymbol(Section, Offset, Symbol, Ctx.UserData)) { 168 // We found a relocation at the given offset in the section, pointing 169 // at a symbol. 170 171 // Try to resolve label/section symbols into function names. 172 Symbol = getPreferredSymbol(Ctx.COFF, Symbol, Displacement, IsRangeEnd); 173 174 Expected<StringRef> Name = Symbol.getName(); 175 if (Name) { 176 OS << *Name; 177 if (Displacement > 0) 178 OS << format(" +0x%X (0x%" PRIX64 ")", Displacement, Offset); 179 else 180 OS << format(" (0x%" PRIX64 ")", Offset); 181 return OS.str(); 182 } else { 183 // TODO: Actually report errors helpfully. 184 consumeError(Name.takeError()); 185 } 186 } else if (!getSymbol(Ctx.COFF, Ctx.COFF.getImageBase() + Displacement, 187 Symbol)) { 188 Expected<StringRef> Name = Symbol.getName(); 189 if (Name) { 190 OS << *Name; 191 OS << format(" (0x%" PRIX64 ")", Ctx.COFF.getImageBase() + Displacement); 192 return OS.str(); 193 } else { 194 consumeError(Name.takeError()); 195 } 196 } 197 198 if (Displacement > 0) 199 OS << format("(0x%" PRIX64 ")", Ctx.COFF.getImageBase() + Displacement); 200 else 201 OS << format("(0x%" PRIX64 ")", Offset); 202 return OS.str(); 203 } 204 205 static std::error_code resolveRelocation(const Dumper::Context &Ctx, 206 const coff_section *Section, 207 uint64_t Offset, 208 const coff_section *&ResolvedSection, 209 uint64_t &ResolvedAddress) { 210 SymbolRef Symbol; 211 if (std::error_code EC = 212 Ctx.ResolveSymbol(Section, Offset, Symbol, Ctx.UserData)) 213 return EC; 214 215 Expected<uint64_t> ResolvedAddressOrErr = Symbol.getAddress(); 216 if (!ResolvedAddressOrErr) 217 return errorToErrorCode(ResolvedAddressOrErr.takeError()); 218 ResolvedAddress = *ResolvedAddressOrErr; 219 220 Expected<section_iterator> SI = Symbol.getSection(); 221 if (!SI) 222 return errorToErrorCode(SI.takeError()); 223 ResolvedSection = Ctx.COFF.getCOFFSection(**SI); 224 return std::error_code(); 225 } 226 227 static const object::coff_section * 228 getSectionContaining(const COFFObjectFile &COFF, uint64_t VA) { 229 for (const auto &Section : COFF.sections()) { 230 uint64_t Address = Section.getAddress(); 231 uint64_t Size = Section.getSize(); 232 233 if (VA >= Address && (VA - Address) <= Size) 234 return COFF.getCOFFSection(Section); 235 } 236 return nullptr; 237 } 238 239 namespace llvm { 240 namespace Win64EH { 241 void Dumper::printRuntimeFunctionEntry(const Context &Ctx, 242 const coff_section *Section, 243 uint64_t Offset, 244 const RuntimeFunction &RF) { 245 SW.printString("StartAddress", 246 formatSymbol(Ctx, Section, Offset + 0, RF.StartAddress)); 247 SW.printString("EndAddress", 248 formatSymbol(Ctx, Section, Offset + 4, RF.EndAddress, 249 /*IsRangeEnd=*/true)); 250 SW.printString("UnwindInfoAddress", 251 formatSymbol(Ctx, Section, Offset + 8, RF.UnwindInfoOffset)); 252 } 253 254 // Prints one unwind code. Because an unwind code can occupy up to 3 slots in 255 // the unwind codes array, this function requires that the correct number of 256 // slots is provided. 257 void Dumper::printUnwindCode(const UnwindInfo& UI, ArrayRef<UnwindCode> UC) { 258 assert(UC.size() >= getNumUsedSlots(UC[0])); 259 260 SW.startLine() << format("0x%02X: ", unsigned(UC[0].u.CodeOffset)) 261 << getUnwindCodeTypeName(UC[0].getUnwindOp()); 262 263 switch (UC[0].getUnwindOp()) { 264 case UOP_PushNonVol: 265 OS << " reg=" << getUnwindRegisterName(UC[0].getOpInfo()); 266 break; 267 268 case UOP_AllocLarge: 269 OS << " size=" 270 << ((UC[0].getOpInfo() == 0) ? UC[1].FrameOffset * 8 271 : getLargeSlotValue(UC)); 272 break; 273 274 case UOP_AllocSmall: 275 OS << " size=" << (UC[0].getOpInfo() + 1) * 8; 276 break; 277 278 case UOP_SetFPReg: 279 if (UI.getFrameRegister() == 0) 280 OS << " reg=<invalid>"; 281 else 282 OS << " reg=" << getUnwindRegisterName(UI.getFrameRegister()) 283 << format(", offset=0x%X", UI.getFrameOffset() * 16); 284 break; 285 286 case UOP_SaveNonVol: 287 OS << " reg=" << getUnwindRegisterName(UC[0].getOpInfo()) 288 << format(", offset=0x%X", UC[1].FrameOffset * 8); 289 break; 290 291 case UOP_SaveNonVolBig: 292 OS << " reg=" << getUnwindRegisterName(UC[0].getOpInfo()) 293 << format(", offset=0x%X", getLargeSlotValue(UC)); 294 break; 295 296 case UOP_SaveXMM128: 297 OS << " reg=XMM" << static_cast<uint32_t>(UC[0].getOpInfo()) 298 << format(", offset=0x%X", UC[1].FrameOffset * 16); 299 break; 300 301 case UOP_SaveXMM128Big: 302 OS << " reg=XMM" << static_cast<uint32_t>(UC[0].getOpInfo()) 303 << format(", offset=0x%X", getLargeSlotValue(UC)); 304 break; 305 306 case UOP_PushMachFrame: 307 OS << " errcode=" << (UC[0].getOpInfo() == 0 ? "no" : "yes"); 308 break; 309 } 310 311 OS << "\n"; 312 } 313 314 void Dumper::printUnwindInfo(const Context &Ctx, const coff_section *Section, 315 off_t Offset, const UnwindInfo &UI) { 316 DictScope UIS(SW, "UnwindInfo"); 317 SW.printNumber("Version", UI.getVersion()); 318 SW.printFlags("Flags", UI.getFlags(), makeArrayRef(UnwindFlags)); 319 SW.printNumber("PrologSize", UI.PrologSize); 320 if (UI.getFrameRegister()) { 321 SW.printEnum("FrameRegister", UI.getFrameRegister(), 322 makeArrayRef(UnwindOpInfo)); 323 SW.printHex("FrameOffset", UI.getFrameOffset()); 324 } else { 325 SW.printString("FrameRegister", StringRef("-")); 326 SW.printString("FrameOffset", StringRef("-")); 327 } 328 329 SW.printNumber("UnwindCodeCount", UI.NumCodes); 330 { 331 ListScope UCS(SW, "UnwindCodes"); 332 ArrayRef<UnwindCode> UC(&UI.UnwindCodes[0], UI.NumCodes); 333 for (const UnwindCode *UCI = UC.begin(), *UCE = UC.end(); UCI < UCE; ++UCI) { 334 unsigned UsedSlots = getNumUsedSlots(*UCI); 335 if (UsedSlots > UC.size()) { 336 errs() << "corrupt unwind data"; 337 return; 338 } 339 340 printUnwindCode(UI, makeArrayRef(UCI, UCE)); 341 UCI = UCI + UsedSlots - 1; 342 } 343 } 344 345 uint64_t LSDAOffset = Offset + getOffsetOfLSDA(UI); 346 if (UI.getFlags() & (UNW_ExceptionHandler | UNW_TerminateHandler)) { 347 SW.printString("Handler", 348 formatSymbol(Ctx, Section, LSDAOffset, 349 UI.getLanguageSpecificHandlerOffset())); 350 } else if (UI.getFlags() & UNW_ChainInfo) { 351 if (const RuntimeFunction *Chained = UI.getChainedFunctionEntry()) { 352 DictScope CS(SW, "Chained"); 353 printRuntimeFunctionEntry(Ctx, Section, LSDAOffset, *Chained); 354 } 355 } 356 } 357 358 void Dumper::printRuntimeFunction(const Context &Ctx, 359 const coff_section *Section, 360 uint64_t SectionOffset, 361 const RuntimeFunction &RF) { 362 DictScope RFS(SW, "RuntimeFunction"); 363 printRuntimeFunctionEntry(Ctx, Section, SectionOffset, RF); 364 365 const coff_section *XData = nullptr; 366 uint64_t Offset; 367 resolveRelocation(Ctx, Section, SectionOffset + 8, XData, Offset); 368 Offset = Offset + RF.UnwindInfoOffset; 369 370 if (!XData) { 371 uint64_t Address = Ctx.COFF.getImageBase() + RF.UnwindInfoOffset; 372 XData = getSectionContaining(Ctx.COFF, Address); 373 if (!XData) 374 return; 375 Offset = RF.UnwindInfoOffset - XData->VirtualAddress; 376 } 377 378 ArrayRef<uint8_t> Contents; 379 if (Error E = Ctx.COFF.getSectionContents(XData, Contents)) 380 reportError(std::move(E), Ctx.COFF.getFileName()); 381 382 if (Contents.empty()) 383 return; 384 385 if (Offset > Contents.size()) 386 return; 387 388 const auto UI = reinterpret_cast<const UnwindInfo*>(Contents.data() + Offset); 389 printUnwindInfo(Ctx, XData, Offset, *UI); 390 } 391 392 void Dumper::printData(const Context &Ctx) { 393 for (const auto &Section : Ctx.COFF.sections()) { 394 StringRef Name; 395 if (Expected<StringRef> NameOrErr = Section.getName()) 396 Name = *NameOrErr; 397 else 398 consumeError(NameOrErr.takeError()); 399 400 if (Name != ".pdata" && !Name.startswith(".pdata$")) 401 continue; 402 403 const coff_section *PData = Ctx.COFF.getCOFFSection(Section); 404 ArrayRef<uint8_t> Contents; 405 406 if (Error E = Ctx.COFF.getSectionContents(PData, Contents)) 407 reportError(std::move(E), Ctx.COFF.getFileName()); 408 if (Contents.empty()) 409 continue; 410 411 const RuntimeFunction *Entries = 412 reinterpret_cast<const RuntimeFunction *>(Contents.data()); 413 const size_t Count = Contents.size() / sizeof(RuntimeFunction); 414 ArrayRef<RuntimeFunction> RuntimeFunctions(Entries, Count); 415 416 size_t Index = 0; 417 for (const auto &RF : RuntimeFunctions) { 418 printRuntimeFunction(Ctx, Ctx.COFF.getCOFFSection(Section), 419 Index * sizeof(RuntimeFunction), RF); 420 ++Index; 421 } 422 } 423 } 424 } 425 } 426 427