1 //===-- COFFDump.cpp - COFF-specific dumper ---------------------*- C++ -*-===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 /// 10 /// \file 11 /// \brief This file implements the COFF-specific dumper for llvm-objdump. 12 /// It outputs the Win64 EH data structures as plain text. 13 /// The encoding of the unwind codes is decribed in MSDN: 14 /// http://msdn.microsoft.com/en-us/library/ck9asaa9.aspx 15 /// 16 //===----------------------------------------------------------------------===// 17 18 #include "llvm-objdump.h" 19 #include "llvm/Object/COFF.h" 20 #include "llvm/Object/ObjectFile.h" 21 #include "llvm/Support/Format.h" 22 #include "llvm/Support/SourceMgr.h" 23 #include "llvm/Support/Win64EH.h" 24 #include "llvm/Support/raw_ostream.h" 25 #include "llvm/Support/system_error.h" 26 #include <algorithm> 27 #include <cstring> 28 29 using namespace llvm; 30 using namespace object; 31 using namespace llvm::Win64EH; 32 33 // Returns the name of the unwind code. 34 static StringRef getUnwindCodeTypeName(uint8_t Code) { 35 switch(Code) { 36 default: llvm_unreachable("Invalid unwind code"); 37 case UOP_PushNonVol: return "UOP_PushNonVol"; 38 case UOP_AllocLarge: return "UOP_AllocLarge"; 39 case UOP_AllocSmall: return "UOP_AllocSmall"; 40 case UOP_SetFPReg: return "UOP_SetFPReg"; 41 case UOP_SaveNonVol: return "UOP_SaveNonVol"; 42 case UOP_SaveNonVolBig: return "UOP_SaveNonVolBig"; 43 case UOP_SaveXMM128: return "UOP_SaveXMM128"; 44 case UOP_SaveXMM128Big: return "UOP_SaveXMM128Big"; 45 case UOP_PushMachFrame: return "UOP_PushMachFrame"; 46 } 47 } 48 49 // Returns the name of a referenced register. 50 static StringRef getUnwindRegisterName(uint8_t Reg) { 51 switch(Reg) { 52 default: llvm_unreachable("Invalid register"); 53 case 0: return "RAX"; 54 case 1: return "RCX"; 55 case 2: return "RDX"; 56 case 3: return "RBX"; 57 case 4: return "RSP"; 58 case 5: return "RBP"; 59 case 6: return "RSI"; 60 case 7: return "RDI"; 61 case 8: return "R8"; 62 case 9: return "R9"; 63 case 10: return "R10"; 64 case 11: return "R11"; 65 case 12: return "R12"; 66 case 13: return "R13"; 67 case 14: return "R14"; 68 case 15: return "R15"; 69 } 70 } 71 72 // Calculates the number of array slots required for the unwind code. 73 static unsigned getNumUsedSlots(const UnwindCode &UnwindCode) { 74 switch (UnwindCode.getUnwindOp()) { 75 default: llvm_unreachable("Invalid unwind code"); 76 case UOP_PushNonVol: 77 case UOP_AllocSmall: 78 case UOP_SetFPReg: 79 case UOP_PushMachFrame: 80 return 1; 81 case UOP_SaveNonVol: 82 case UOP_SaveXMM128: 83 return 2; 84 case UOP_SaveNonVolBig: 85 case UOP_SaveXMM128Big: 86 return 3; 87 case UOP_AllocLarge: 88 return (UnwindCode.getOpInfo() == 0) ? 2 : 3; 89 } 90 } 91 92 // Prints one unwind code. Because an unwind code can occupy up to 3 slots in 93 // the unwind codes array, this function requires that the correct number of 94 // slots is provided. 95 static void printUnwindCode(ArrayRef<UnwindCode> UCs) { 96 assert(UCs.size() >= getNumUsedSlots(UCs[0])); 97 outs() << format(" 0x%02x: ", unsigned(UCs[0].u.CodeOffset)) 98 << getUnwindCodeTypeName(UCs[0].getUnwindOp()); 99 switch (UCs[0].getUnwindOp()) { 100 case UOP_PushNonVol: 101 outs() << " " << getUnwindRegisterName(UCs[0].getOpInfo()); 102 break; 103 case UOP_AllocLarge: 104 if (UCs[0].getOpInfo() == 0) { 105 outs() << " " << UCs[1].FrameOffset; 106 } else { 107 outs() << " " << UCs[1].FrameOffset 108 + (static_cast<uint32_t>(UCs[2].FrameOffset) << 16); 109 } 110 break; 111 case UOP_AllocSmall: 112 outs() << " " << ((UCs[0].getOpInfo() + 1) * 8); 113 break; 114 case UOP_SetFPReg: 115 outs() << " "; 116 break; 117 case UOP_SaveNonVol: 118 outs() << " " << getUnwindRegisterName(UCs[0].getOpInfo()) 119 << format(" [0x%04x]", 8 * UCs[1].FrameOffset); 120 break; 121 case UOP_SaveNonVolBig: 122 outs() << " " << getUnwindRegisterName(UCs[0].getOpInfo()) 123 << format(" [0x%08x]", UCs[1].FrameOffset 124 + (static_cast<uint32_t>(UCs[2].FrameOffset) << 16)); 125 break; 126 case UOP_SaveXMM128: 127 outs() << " XMM" << static_cast<uint32_t>(UCs[0].getOpInfo()) 128 << format(" [0x%04x]", 16 * UCs[1].FrameOffset); 129 break; 130 case UOP_SaveXMM128Big: 131 outs() << " XMM" << UCs[0].getOpInfo() 132 << format(" [0x%08x]", UCs[1].FrameOffset 133 + (static_cast<uint32_t>(UCs[2].FrameOffset) << 16)); 134 break; 135 case UOP_PushMachFrame: 136 outs() << " " << (UCs[0].getOpInfo() ? "w/o" : "w") 137 << " error code"; 138 break; 139 } 140 outs() << "\n"; 141 } 142 143 static void printAllUnwindCodes(ArrayRef<UnwindCode> UCs) { 144 for (const UnwindCode *I = UCs.begin(), *E = UCs.end(); I < E; ) { 145 unsigned UsedSlots = getNumUsedSlots(*I); 146 if (UsedSlots > UCs.size()) { 147 outs() << "Unwind data corrupted: Encountered unwind op " 148 << getUnwindCodeTypeName((*I).getUnwindOp()) 149 << " which requires " << UsedSlots 150 << " slots, but only " << UCs.size() 151 << " remaining in buffer"; 152 return ; 153 } 154 printUnwindCode(ArrayRef<UnwindCode>(I, E)); 155 I += UsedSlots; 156 } 157 } 158 159 // Given a symbol sym this functions returns the address and section of it. 160 static error_code resolveSectionAndAddress(const COFFObjectFile *Obj, 161 const SymbolRef &Sym, 162 const coff_section *&ResolvedSection, 163 uint64_t &ResolvedAddr) { 164 if (error_code ec = Sym.getAddress(ResolvedAddr)) return ec; 165 section_iterator iter(Obj->begin_sections()); 166 if (error_code ec = Sym.getSection(iter)) return ec; 167 ResolvedSection = Obj->getCOFFSection(iter); 168 return object_error::success; 169 } 170 171 // Given a vector of relocations for a section and an offset into this section 172 // the function returns the symbol used for the relocation at the offset. 173 static error_code resolveSymbol(const std::vector<RelocationRef> &Rels, 174 uint64_t Offset, SymbolRef &Sym) { 175 for (std::vector<RelocationRef>::const_iterator I = Rels.begin(), 176 E = Rels.end(); 177 I != E; ++I) { 178 uint64_t Ofs; 179 if (error_code ec = I->getOffset(Ofs)) return ec; 180 if (Ofs == Offset) { 181 if (error_code ec = I->getSymbol(Sym)) return ec; 182 break; 183 } 184 } 185 return object_error::success; 186 } 187 188 // Given a vector of relocations for a section and an offset into this section 189 // the function resolves the symbol used for the relocation at the offset and 190 // returns the section content and the address inside the content pointed to 191 // by the symbol. 192 static error_code getSectionContents(const COFFObjectFile *Obj, 193 const std::vector<RelocationRef> &Rels, 194 uint64_t Offset, 195 ArrayRef<uint8_t> &Contents, 196 uint64_t &Addr) { 197 SymbolRef Sym; 198 if (error_code ec = resolveSymbol(Rels, Offset, Sym)) return ec; 199 const coff_section *Section; 200 if (error_code ec = resolveSectionAndAddress(Obj, Sym, Section, Addr)) 201 return ec; 202 if (error_code ec = Obj->getSectionContents(Section, Contents)) return ec; 203 return object_error::success; 204 } 205 206 // Given a vector of relocations for a section and an offset into this section 207 // the function returns the name of the symbol used for the relocation at the 208 // offset. 209 static error_code resolveSymbolName(const std::vector<RelocationRef> &Rels, 210 uint64_t Offset, StringRef &Name) { 211 SymbolRef Sym; 212 if (error_code ec = resolveSymbol(Rels, Offset, Sym)) return ec; 213 if (error_code ec = Sym.getName(Name)) return ec; 214 return object_error::success; 215 } 216 217 static void printCOFFSymbolAddress(llvm::raw_ostream &Out, 218 const std::vector<RelocationRef> &Rels, 219 uint64_t Offset, uint32_t Disp) { 220 StringRef Sym; 221 if (error_code ec = resolveSymbolName(Rels, Offset, Sym)) { 222 error(ec); 223 return ; 224 } 225 Out << Sym; 226 if (Disp > 0) 227 Out << format(" + 0x%04x", Disp); 228 } 229 230 void llvm::printCOFFUnwindInfo(const COFFObjectFile *Obj) { 231 const coff_file_header *Header; 232 if (error(Obj->getHeader(Header))) return; 233 234 if (Header->Machine != COFF::IMAGE_FILE_MACHINE_AMD64) { 235 errs() << "Unsupported image machine type " 236 "(currently only AMD64 is supported).\n"; 237 return; 238 } 239 240 const coff_section *Pdata = 0; 241 242 error_code ec; 243 for (section_iterator SI = Obj->begin_sections(), 244 SE = Obj->end_sections(); 245 SI != SE; SI.increment(ec)) { 246 if (error(ec)) return; 247 248 StringRef Name; 249 if (error(SI->getName(Name))) continue; 250 251 if (Name != ".pdata") continue; 252 253 Pdata = Obj->getCOFFSection(SI); 254 std::vector<RelocationRef> Rels; 255 for (relocation_iterator RI = SI->begin_relocations(), 256 RE = SI->end_relocations(); 257 RI != RE; RI.increment(ec)) { 258 if (error(ec)) break; 259 Rels.push_back(*RI); 260 } 261 262 // Sort relocations by address. 263 std::sort(Rels.begin(), Rels.end(), RelocAddressLess); 264 265 ArrayRef<uint8_t> Contents; 266 if (error(Obj->getSectionContents(Pdata, Contents))) continue; 267 if (Contents.empty()) continue; 268 269 ArrayRef<RuntimeFunction> RFs( 270 reinterpret_cast<const RuntimeFunction *>(Contents.data()), 271 Contents.size() / sizeof(RuntimeFunction)); 272 for (const RuntimeFunction *I = RFs.begin(), *E = RFs.end(); I < E; ++I) { 273 const uint64_t SectionOffset = std::distance(RFs.begin(), I) 274 * sizeof(RuntimeFunction); 275 276 outs() << "Function Table:\n"; 277 278 outs() << " Start Address: "; 279 printCOFFSymbolAddress(outs(), Rels, SectionOffset + 280 /*offsetof(RuntimeFunction, StartAddress)*/ 0, 281 I->StartAddress); 282 outs() << "\n"; 283 284 outs() << " End Address: "; 285 printCOFFSymbolAddress(outs(), Rels, SectionOffset + 286 /*offsetof(RuntimeFunction, EndAddress)*/ 4, 287 I->EndAddress); 288 outs() << "\n"; 289 290 outs() << " Unwind Info Address: "; 291 printCOFFSymbolAddress(outs(), Rels, SectionOffset + 292 /*offsetof(RuntimeFunction, UnwindInfoOffset)*/ 8, 293 I->UnwindInfoOffset); 294 outs() << "\n"; 295 296 ArrayRef<uint8_t> XContents; 297 uint64_t UnwindInfoOffset = 0; 298 if (error(getSectionContents(Obj, Rels, SectionOffset + 299 /*offsetof(RuntimeFunction, UnwindInfoOffset)*/ 8, 300 XContents, UnwindInfoOffset))) continue; 301 if (XContents.empty()) continue; 302 303 UnwindInfoOffset += I->UnwindInfoOffset; 304 if (UnwindInfoOffset > XContents.size()) continue; 305 306 const Win64EH::UnwindInfo *UI = 307 reinterpret_cast<const Win64EH::UnwindInfo *> 308 (XContents.data() + UnwindInfoOffset); 309 310 // The casts to int are required in order to output the value as number. 311 // Without the casts the value would be interpreted as char data (which 312 // results in garbage output). 313 outs() << " Version: " << static_cast<int>(UI->getVersion()) << "\n"; 314 outs() << " Flags: " << static_cast<int>(UI->getFlags()); 315 if (UI->getFlags()) { 316 if (UI->getFlags() & UNW_ExceptionHandler) 317 outs() << " UNW_ExceptionHandler"; 318 if (UI->getFlags() & UNW_TerminateHandler) 319 outs() << " UNW_TerminateHandler"; 320 if (UI->getFlags() & UNW_ChainInfo) 321 outs() << " UNW_ChainInfo"; 322 } 323 outs() << "\n"; 324 outs() << " Size of prolog: " 325 << static_cast<int>(UI->PrologSize) << "\n"; 326 outs() << " Number of Codes: " 327 << static_cast<int>(UI->NumCodes) << "\n"; 328 // Maybe this should move to output of UOP_SetFPReg? 329 if (UI->getFrameRegister()) { 330 outs() << " Frame register: " 331 << getUnwindRegisterName(UI->getFrameRegister()) 332 << "\n"; 333 outs() << " Frame offset: " 334 << 16 * UI->getFrameOffset() 335 << "\n"; 336 } else { 337 outs() << " No frame pointer used\n"; 338 } 339 if (UI->getFlags() & (UNW_ExceptionHandler | UNW_TerminateHandler)) { 340 // FIXME: Output exception handler data 341 } else if (UI->getFlags() & UNW_ChainInfo) { 342 // FIXME: Output chained unwind info 343 } 344 345 if (UI->NumCodes) 346 outs() << " Unwind Codes:\n"; 347 348 printAllUnwindCodes(ArrayRef<UnwindCode>(&UI->UnwindCodes[0], 349 UI->NumCodes)); 350 351 outs() << "\n\n"; 352 outs().flush(); 353 } 354 } 355 } 356
