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      1 //===- Win64EHDumper.cpp - Win64 EH Printer ---------------------*- 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 #include "Win64EHDumper.h"
     11 #include "llvm-readobj.h"
     12 #include "llvm/Object/COFF.h"
     13 #include "llvm/Support/ErrorHandling.h"
     14 #include "llvm/Support/Format.h"
     15 
     16 using namespace llvm;
     17 using namespace llvm::object;
     18 using namespace llvm::Win64EH;
     19 
     20 static const EnumEntry<unsigned> UnwindFlags[] = {
     21   { "ExceptionHandler", UNW_ExceptionHandler },
     22   { "TerminateHandler", UNW_TerminateHandler },
     23   { "ChainInfo"       , UNW_ChainInfo        }
     24 };
     25 
     26 static const EnumEntry<unsigned> UnwindOpInfo[] = {
     27   { "RAX",  0 },
     28   { "RCX",  1 },
     29   { "RDX",  2 },
     30   { "RBX",  3 },
     31   { "RSP",  4 },
     32   { "RBP",  5 },
     33   { "RSI",  6 },
     34   { "RDI",  7 },
     35   { "R8",   8 },
     36   { "R9",   9 },
     37   { "R10", 10 },
     38   { "R11", 11 },
     39   { "R12", 12 },
     40   { "R13", 13 },
     41   { "R14", 14 },
     42   { "R15", 15 }
     43 };
     44 
     45 static uint64_t getOffsetOfLSDA(const UnwindInfo& UI) {
     46   return static_cast<const char*>(UI.getLanguageSpecificData())
     47          - reinterpret_cast<const char*>(&UI);
     48 }
     49 
     50 static uint32_t getLargeSlotValue(ArrayRef<UnwindCode> UC) {
     51   if (UC.size() < 3)
     52     return 0;
     53   return UC[1].FrameOffset + (static_cast<uint32_t>(UC[2].FrameOffset) << 16);
     54 }
     55 
     56 // Returns the name of the unwind code.
     57 static StringRef getUnwindCodeTypeName(uint8_t Code) {
     58   switch (Code) {
     59   default: llvm_unreachable("Invalid unwind code");
     60   case UOP_PushNonVol: return "PUSH_NONVOL";
     61   case UOP_AllocLarge: return "ALLOC_LARGE";
     62   case UOP_AllocSmall: return "ALLOC_SMALL";
     63   case UOP_SetFPReg: return "SET_FPREG";
     64   case UOP_SaveNonVol: return "SAVE_NONVOL";
     65   case UOP_SaveNonVolBig: return "SAVE_NONVOL_FAR";
     66   case UOP_SaveXMM128: return "SAVE_XMM128";
     67   case UOP_SaveXMM128Big: return "SAVE_XMM128_FAR";
     68   case UOP_PushMachFrame: return "PUSH_MACHFRAME";
     69   }
     70 }
     71 
     72 // Returns the name of a referenced register.
     73 static StringRef getUnwindRegisterName(uint8_t Reg) {
     74   switch (Reg) {
     75   default: llvm_unreachable("Invalid register");
     76   case 0: return "RAX";
     77   case 1: return "RCX";
     78   case 2: return "RDX";
     79   case 3: return "RBX";
     80   case 4: return "RSP";
     81   case 5: return "RBP";
     82   case 6: return "RSI";
     83   case 7: return "RDI";
     84   case 8: return "R8";
     85   case 9: return "R9";
     86   case 10: return "R10";
     87   case 11: return "R11";
     88   case 12: return "R12";
     89   case 13: return "R13";
     90   case 14: return "R14";
     91   case 15: return "R15";
     92   }
     93 }
     94 
     95 // Calculates the number of array slots required for the unwind code.
     96 static unsigned getNumUsedSlots(const UnwindCode &UnwindCode) {
     97   switch (UnwindCode.getUnwindOp()) {
     98   default: llvm_unreachable("Invalid unwind code");
     99   case UOP_PushNonVol:
    100   case UOP_AllocSmall:
    101   case UOP_SetFPReg:
    102   case UOP_PushMachFrame:
    103     return 1;
    104   case UOP_SaveNonVol:
    105   case UOP_SaveXMM128:
    106     return 2;
    107   case UOP_SaveNonVolBig:
    108   case UOP_SaveXMM128Big:
    109     return 3;
    110   case UOP_AllocLarge:
    111     return (UnwindCode.getOpInfo() == 0) ? 2 : 3;
    112   }
    113 }
    114 
    115 static std::string formatSymbol(const Dumper::Context &Ctx,
    116                                 const coff_section *Section, uint64_t Offset,
    117                                 uint32_t Displacement) {
    118   std::string Buffer;
    119   raw_string_ostream OS(Buffer);
    120 
    121   SymbolRef Symbol;
    122   if (!Ctx.ResolveSymbol(Section, Offset, Symbol, Ctx.UserData)) {
    123     if (ErrorOr<StringRef> Name = Symbol.getName()) {
    124       OS << *Name;
    125       if (Displacement > 0)
    126         OS << format(" +0x%X (0x%" PRIX64 ")", Displacement, Offset);
    127       else
    128         OS << format(" (0x%" PRIX64 ")", Offset);
    129       return OS.str();
    130     }
    131   }
    132 
    133   OS << format(" (0x%" PRIX64 ")", Offset);
    134   return OS.str();
    135 }
    136 
    137 static std::error_code resolveRelocation(const Dumper::Context &Ctx,
    138                                          const coff_section *Section,
    139                                          uint64_t Offset,
    140                                          const coff_section *&ResolvedSection,
    141                                          uint64_t &ResolvedAddress) {
    142   SymbolRef Symbol;
    143   if (std::error_code EC =
    144           Ctx.ResolveSymbol(Section, Offset, Symbol, Ctx.UserData))
    145     return EC;
    146 
    147   ErrorOr<uint64_t> ResolvedAddressOrErr = Symbol.getAddress();
    148   if (std::error_code EC = ResolvedAddressOrErr.getError())
    149     return EC;
    150   ResolvedAddress = *ResolvedAddressOrErr;
    151 
    152   ErrorOr<section_iterator> SI = Symbol.getSection();
    153   ResolvedSection = Ctx.COFF.getCOFFSection(**SI);
    154   return std::error_code();
    155 }
    156 
    157 namespace llvm {
    158 namespace Win64EH {
    159 void Dumper::printRuntimeFunctionEntry(const Context &Ctx,
    160                                        const coff_section *Section,
    161                                        uint64_t Offset,
    162                                        const RuntimeFunction &RF) {
    163   SW.printString("StartAddress",
    164                  formatSymbol(Ctx, Section, Offset + 0, RF.StartAddress));
    165   SW.printString("EndAddress",
    166                  formatSymbol(Ctx, Section, Offset + 4, RF.EndAddress));
    167   SW.printString("UnwindInfoAddress",
    168                  formatSymbol(Ctx, Section, Offset + 8, RF.UnwindInfoOffset));
    169 }
    170 
    171 // Prints one unwind code. Because an unwind code can occupy up to 3 slots in
    172 // the unwind codes array, this function requires that the correct number of
    173 // slots is provided.
    174 void Dumper::printUnwindCode(const UnwindInfo& UI, ArrayRef<UnwindCode> UC) {
    175   assert(UC.size() >= getNumUsedSlots(UC[0]));
    176 
    177   SW.startLine() << format("0x%02X: ", unsigned(UC[0].u.CodeOffset))
    178                  << getUnwindCodeTypeName(UC[0].getUnwindOp());
    179 
    180   switch (UC[0].getUnwindOp()) {
    181   case UOP_PushNonVol:
    182     OS << " reg=" << getUnwindRegisterName(UC[0].getOpInfo());
    183     break;
    184 
    185   case UOP_AllocLarge:
    186     OS << " size="
    187        << ((UC[0].getOpInfo() == 0) ? UC[1].FrameOffset * 8
    188                                     : getLargeSlotValue(UC));
    189     break;
    190 
    191   case UOP_AllocSmall:
    192     OS << " size=" << (UC[0].getOpInfo() + 1) * 8;
    193     break;
    194 
    195   case UOP_SetFPReg:
    196     if (UI.getFrameRegister() == 0)
    197       OS << " reg=<invalid>";
    198     else
    199       OS << " reg=" << getUnwindRegisterName(UI.getFrameRegister())
    200          << format(", offset=0x%X", UI.getFrameOffset() * 16);
    201     break;
    202 
    203   case UOP_SaveNonVol:
    204     OS << " reg=" << getUnwindRegisterName(UC[0].getOpInfo())
    205        << format(", offset=0x%X", UC[1].FrameOffset * 8);
    206     break;
    207 
    208   case UOP_SaveNonVolBig:
    209     OS << " reg=" << getUnwindRegisterName(UC[0].getOpInfo())
    210        << format(", offset=0x%X", getLargeSlotValue(UC));
    211     break;
    212 
    213   case UOP_SaveXMM128:
    214     OS << " reg=XMM" << static_cast<uint32_t>(UC[0].getOpInfo())
    215        << format(", offset=0x%X", UC[1].FrameOffset * 16);
    216     break;
    217 
    218   case UOP_SaveXMM128Big:
    219     OS << " reg=XMM" << static_cast<uint32_t>(UC[0].getOpInfo())
    220        << format(", offset=0x%X", getLargeSlotValue(UC));
    221     break;
    222 
    223   case UOP_PushMachFrame:
    224     OS << " errcode=" << (UC[0].getOpInfo() == 0 ? "no" : "yes");
    225     break;
    226   }
    227 
    228   OS << "\n";
    229 }
    230 
    231 void Dumper::printUnwindInfo(const Context &Ctx, const coff_section *Section,
    232                              off_t Offset, const UnwindInfo &UI) {
    233   DictScope UIS(SW, "UnwindInfo");
    234   SW.printNumber("Version", UI.getVersion());
    235   SW.printFlags("Flags", UI.getFlags(), makeArrayRef(UnwindFlags));
    236   SW.printNumber("PrologSize", UI.PrologSize);
    237   if (UI.getFrameRegister()) {
    238     SW.printEnum("FrameRegister", UI.getFrameRegister(),
    239                  makeArrayRef(UnwindOpInfo));
    240     SW.printHex("FrameOffset", UI.getFrameOffset());
    241   } else {
    242     SW.printString("FrameRegister", StringRef("-"));
    243     SW.printString("FrameOffset", StringRef("-"));
    244   }
    245 
    246   SW.printNumber("UnwindCodeCount", UI.NumCodes);
    247   {
    248     ListScope UCS(SW, "UnwindCodes");
    249     ArrayRef<UnwindCode> UC(&UI.UnwindCodes[0], UI.NumCodes);
    250     for (const UnwindCode *UCI = UC.begin(), *UCE = UC.end(); UCI < UCE; ++UCI) {
    251       unsigned UsedSlots = getNumUsedSlots(*UCI);
    252       if (UsedSlots > UC.size()) {
    253         errs() << "corrupt unwind data";
    254         return;
    255       }
    256 
    257       printUnwindCode(UI, makeArrayRef(UCI, UCE));
    258       UCI = UCI + UsedSlots - 1;
    259     }
    260   }
    261 
    262   uint64_t LSDAOffset = Offset + getOffsetOfLSDA(UI);
    263   if (UI.getFlags() & (UNW_ExceptionHandler | UNW_TerminateHandler)) {
    264     SW.printString("Handler",
    265                    formatSymbol(Ctx, Section, LSDAOffset,
    266                                 UI.getLanguageSpecificHandlerOffset()));
    267   } else if (UI.getFlags() & UNW_ChainInfo) {
    268     if (const RuntimeFunction *Chained = UI.getChainedFunctionEntry()) {
    269       DictScope CS(SW, "Chained");
    270       printRuntimeFunctionEntry(Ctx, Section, LSDAOffset, *Chained);
    271     }
    272   }
    273 }
    274 
    275 void Dumper::printRuntimeFunction(const Context &Ctx,
    276                                   const coff_section *Section,
    277                                   uint64_t SectionOffset,
    278                                   const RuntimeFunction &RF) {
    279   DictScope RFS(SW, "RuntimeFunction");
    280   printRuntimeFunctionEntry(Ctx, Section, SectionOffset, RF);
    281 
    282   const coff_section *XData;
    283   uint64_t Offset;
    284   resolveRelocation(Ctx, Section, SectionOffset + 8, XData, Offset);
    285 
    286   ArrayRef<uint8_t> Contents;
    287   error(Ctx.COFF.getSectionContents(XData, Contents));
    288   if (Contents.empty())
    289     return;
    290 
    291   Offset = Offset + RF.UnwindInfoOffset;
    292   if (Offset > Contents.size())
    293     return;
    294 
    295   const auto UI = reinterpret_cast<const UnwindInfo*>(Contents.data() + Offset);
    296   printUnwindInfo(Ctx, XData, Offset, *UI);
    297 }
    298 
    299 void Dumper::printData(const Context &Ctx) {
    300   for (const auto &Section : Ctx.COFF.sections()) {
    301     StringRef Name;
    302     Section.getName(Name);
    303 
    304     if (Name != ".pdata" && !Name.startswith(".pdata$"))
    305       continue;
    306 
    307     const coff_section *PData = Ctx.COFF.getCOFFSection(Section);
    308     ArrayRef<uint8_t> Contents;
    309     error(Ctx.COFF.getSectionContents(PData, Contents));
    310     if (Contents.empty())
    311       continue;
    312 
    313     const RuntimeFunction *Entries =
    314       reinterpret_cast<const RuntimeFunction *>(Contents.data());
    315     const size_t Count = Contents.size() / sizeof(RuntimeFunction);
    316     ArrayRef<RuntimeFunction> RuntimeFunctions(Entries, Count);
    317 
    318     size_t Index = 0;
    319     for (const auto &RF : RuntimeFunctions) {
    320       printRuntimeFunction(Ctx, Ctx.COFF.getCOFFSection(Section),
    321                            Index * sizeof(RuntimeFunction), RF);
    322       ++Index;
    323     }
    324   }
    325 }
    326 }
    327 }
    328 
    329