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      1 //===-- MachODump.cpp - Object file dumping utility for llvm --------------===//
      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 // This file implements the MachO-specific dumper for llvm-readobj.
     11 //
     12 //===----------------------------------------------------------------------===//
     13 
     14 #include "llvm-readobj.h"
     15 #include "Error.h"
     16 #include "ObjDumper.h"
     17 #include "StreamWriter.h"
     18 #include "llvm/ADT/SmallString.h"
     19 #include "llvm/ADT/StringExtras.h"
     20 #include "llvm/Object/MachO.h"
     21 #include "llvm/Support/Casting.h"
     22 
     23 using namespace llvm;
     24 using namespace object;
     25 
     26 namespace {
     27 
     28 class MachODumper : public ObjDumper {
     29 public:
     30   MachODumper(const MachOObjectFile *Obj, StreamWriter& Writer)
     31     : ObjDumper(Writer)
     32     , Obj(Obj) { }
     33 
     34   virtual void printFileHeaders() override;
     35   virtual void printSections() override;
     36   virtual void printRelocations() override;
     37   virtual void printSymbols() override;
     38   virtual void printDynamicSymbols() override;
     39   virtual void printUnwindInfo() override;
     40 
     41 private:
     42   void printSymbol(const SymbolRef &Symbol);
     43 
     44   void printRelocation(const RelocationRef &Reloc);
     45 
     46   void printRelocation(const MachOObjectFile *Obj, const RelocationRef &Reloc);
     47 
     48   void printSections(const MachOObjectFile *Obj);
     49 
     50   const MachOObjectFile *Obj;
     51 };
     52 
     53 } // namespace
     54 
     55 
     56 namespace llvm {
     57 
     58 std::error_code createMachODumper(const object::ObjectFile *Obj,
     59                                   StreamWriter &Writer,
     60                                   std::unique_ptr<ObjDumper> &Result) {
     61   const MachOObjectFile *MachOObj = dyn_cast<MachOObjectFile>(Obj);
     62   if (!MachOObj)
     63     return readobj_error::unsupported_obj_file_format;
     64 
     65   Result.reset(new MachODumper(MachOObj, Writer));
     66   return readobj_error::success;
     67 }
     68 
     69 } // namespace llvm
     70 
     71 
     72 static const EnumEntry<unsigned> MachOSectionTypes[] = {
     73   { "Regular"                        , 0x00 },
     74   { "ZeroFill"                       , 0x01 },
     75   { "CStringLiterals"                , 0x02 },
     76   { "4ByteLiterals"                  , 0x03 },
     77   { "8ByteLiterals"                  , 0x04 },
     78   { "LiteralPointers"                , 0x05 },
     79   { "NonLazySymbolPointers"          , 0x06 },
     80   { "LazySymbolPointers"             , 0x07 },
     81   { "SymbolStubs"                    , 0x08 },
     82   { "ModInitFuncs"                   , 0x09 },
     83   { "ModTermFuncs"                   , 0x0A },
     84   { "Coalesced"                      , 0x0B },
     85   { "GBZeroFill"                     , 0x0C },
     86   { "Interposing"                    , 0x0D },
     87   { "16ByteLiterals"                 , 0x0E },
     88   { "DTraceDOF"                      , 0x0F },
     89   { "LazyDylibSymbolPoints"          , 0x10 },
     90   { "ThreadLocalRegular"             , 0x11 },
     91   { "ThreadLocalZerofill"            , 0x12 },
     92   { "ThreadLocalVariables"           , 0x13 },
     93   { "ThreadLocalVariablePointers"    , 0x14 },
     94   { "ThreadLocalInitFunctionPointers", 0x15 }
     95 };
     96 
     97 static const EnumEntry<unsigned> MachOSectionAttributes[] = {
     98   { "LocReloc"         , 1 <<  0 /*S_ATTR_LOC_RELOC          */ },
     99   { "ExtReloc"         , 1 <<  1 /*S_ATTR_EXT_RELOC          */ },
    100   { "SomeInstructions" , 1 <<  2 /*S_ATTR_SOME_INSTRUCTIONS  */ },
    101   { "Debug"            , 1 << 17 /*S_ATTR_DEBUG              */ },
    102   { "SelfModifyingCode", 1 << 18 /*S_ATTR_SELF_MODIFYING_CODE*/ },
    103   { "LiveSupport"      , 1 << 19 /*S_ATTR_LIVE_SUPPORT       */ },
    104   { "NoDeadStrip"      , 1 << 20 /*S_ATTR_NO_DEAD_STRIP      */ },
    105   { "StripStaticSyms"  , 1 << 21 /*S_ATTR_STRIP_STATIC_SYMS  */ },
    106   { "NoTOC"            , 1 << 22 /*S_ATTR_NO_TOC             */ },
    107   { "PureInstructions" , 1 << 23 /*S_ATTR_PURE_INSTRUCTIONS  */ },
    108 };
    109 
    110 static const EnumEntry<unsigned> MachOSymbolRefTypes[] = {
    111   { "UndefinedNonLazy",                     0 },
    112   { "ReferenceFlagUndefinedLazy",           1 },
    113   { "ReferenceFlagDefined",                 2 },
    114   { "ReferenceFlagPrivateDefined",          3 },
    115   { "ReferenceFlagPrivateUndefinedNonLazy", 4 },
    116   { "ReferenceFlagPrivateUndefinedLazy",    5 }
    117 };
    118 
    119 static const EnumEntry<unsigned> MachOSymbolFlags[] = {
    120   { "ReferencedDynamically", 0x10 },
    121   { "NoDeadStrip",           0x20 },
    122   { "WeakRef",               0x40 },
    123   { "WeakDef",               0x80 }
    124 };
    125 
    126 static const EnumEntry<unsigned> MachOSymbolTypes[] = {
    127   { "Undef",           0x0 },
    128   { "Abs",             0x2 },
    129   { "Indirect",        0xA },
    130   { "PreboundUndef",   0xC },
    131   { "Section",         0xE }
    132 };
    133 
    134 namespace {
    135   struct MachOSection {
    136     ArrayRef<char> Name;
    137     ArrayRef<char> SegmentName;
    138     uint64_t Address;
    139     uint64_t Size;
    140     uint32_t Offset;
    141     uint32_t Alignment;
    142     uint32_t RelocationTableOffset;
    143     uint32_t NumRelocationTableEntries;
    144     uint32_t Flags;
    145     uint32_t Reserved1;
    146     uint32_t Reserved2;
    147   };
    148 
    149   struct MachOSymbol {
    150     uint32_t StringIndex;
    151     uint8_t Type;
    152     uint8_t SectionIndex;
    153     uint16_t Flags;
    154     uint64_t Value;
    155   };
    156 }
    157 
    158 static void getSection(const MachOObjectFile *Obj,
    159                        DataRefImpl Sec,
    160                        MachOSection &Section) {
    161   if (!Obj->is64Bit()) {
    162     MachO::section Sect = Obj->getSection(Sec);
    163     Section.Address     = Sect.addr;
    164     Section.Size        = Sect.size;
    165     Section.Offset      = Sect.offset;
    166     Section.Alignment   = Sect.align;
    167     Section.RelocationTableOffset = Sect.reloff;
    168     Section.NumRelocationTableEntries = Sect.nreloc;
    169     Section.Flags       = Sect.flags;
    170     Section.Reserved1   = Sect.reserved1;
    171     Section.Reserved2   = Sect.reserved2;
    172     return;
    173   }
    174   MachO::section_64 Sect = Obj->getSection64(Sec);
    175   Section.Address     = Sect.addr;
    176   Section.Size        = Sect.size;
    177   Section.Offset      = Sect.offset;
    178   Section.Alignment   = Sect.align;
    179   Section.RelocationTableOffset = Sect.reloff;
    180   Section.NumRelocationTableEntries = Sect.nreloc;
    181   Section.Flags       = Sect.flags;
    182   Section.Reserved1   = Sect.reserved1;
    183   Section.Reserved2   = Sect.reserved2;
    184 }
    185 
    186 
    187 static void getSymbol(const MachOObjectFile *Obj,
    188                       DataRefImpl DRI,
    189                       MachOSymbol &Symbol) {
    190   if (!Obj->is64Bit()) {
    191     MachO::nlist Entry = Obj->getSymbolTableEntry(DRI);
    192     Symbol.StringIndex  = Entry.n_strx;
    193     Symbol.Type         = Entry.n_type;
    194     Symbol.SectionIndex = Entry.n_sect;
    195     Symbol.Flags        = Entry.n_desc;
    196     Symbol.Value        = Entry.n_value;
    197     return;
    198   }
    199   MachO::nlist_64 Entry = Obj->getSymbol64TableEntry(DRI);
    200   Symbol.StringIndex  = Entry.n_strx;
    201   Symbol.Type         = Entry.n_type;
    202   Symbol.SectionIndex = Entry.n_sect;
    203   Symbol.Flags        = Entry.n_desc;
    204   Symbol.Value        = Entry.n_value;
    205 }
    206 
    207 void MachODumper::printFileHeaders() {
    208   W.startLine() << "FileHeaders not implemented.\n";
    209 }
    210 
    211 void MachODumper::printSections() {
    212   return printSections(Obj);
    213 }
    214 
    215 void MachODumper::printSections(const MachOObjectFile *Obj) {
    216   ListScope Group(W, "Sections");
    217 
    218   int SectionIndex = -1;
    219   for (const SectionRef &Section : Obj->sections()) {
    220     ++SectionIndex;
    221 
    222     MachOSection MOSection;
    223     getSection(Obj, Section.getRawDataRefImpl(), MOSection);
    224     DataRefImpl DR = Section.getRawDataRefImpl();
    225 
    226     StringRef Name;
    227     if (error(Section.getName(Name)))
    228       Name = "";
    229 
    230     ArrayRef<char> RawName = Obj->getSectionRawName(DR);
    231     StringRef SegmentName = Obj->getSectionFinalSegmentName(DR);
    232     ArrayRef<char> RawSegmentName = Obj->getSectionRawFinalSegmentName(DR);
    233 
    234     DictScope SectionD(W, "Section");
    235     W.printNumber("Index", SectionIndex);
    236     W.printBinary("Name", Name, RawName);
    237     W.printBinary("Segment", SegmentName, RawSegmentName);
    238     W.printHex("Address", MOSection.Address);
    239     W.printHex("Size", MOSection.Size);
    240     W.printNumber("Offset", MOSection.Offset);
    241     W.printNumber("Alignment", MOSection.Alignment);
    242     W.printHex("RelocationOffset", MOSection.RelocationTableOffset);
    243     W.printNumber("RelocationCount", MOSection.NumRelocationTableEntries);
    244     W.printEnum("Type", MOSection.Flags & 0xFF,
    245                 makeArrayRef(MachOSectionAttributes));
    246     W.printFlags("Attributes", MOSection.Flags >> 8,
    247                  makeArrayRef(MachOSectionAttributes));
    248     W.printHex("Reserved1", MOSection.Reserved1);
    249     W.printHex("Reserved2", MOSection.Reserved2);
    250 
    251     if (opts::SectionRelocations) {
    252       ListScope D(W, "Relocations");
    253       for (const RelocationRef &Reloc : Section.relocations())
    254         printRelocation(Reloc);
    255     }
    256 
    257     if (opts::SectionSymbols) {
    258       ListScope D(W, "Symbols");
    259       for (const SymbolRef &Symbol : Obj->symbols()) {
    260         bool Contained = false;
    261         if (Section.containsSymbol(Symbol, Contained) || !Contained)
    262           continue;
    263 
    264         printSymbol(Symbol);
    265       }
    266     }
    267 
    268     if (opts::SectionData) {
    269       StringRef Data;
    270       if (error(Section.getContents(Data)))
    271         break;
    272 
    273       W.printBinaryBlock("SectionData", Data);
    274     }
    275   }
    276 }
    277 
    278 void MachODumper::printRelocations() {
    279   ListScope D(W, "Relocations");
    280 
    281   std::error_code EC;
    282   for (const SectionRef &Section : Obj->sections()) {
    283     StringRef Name;
    284     if (error(Section.getName(Name)))
    285       continue;
    286 
    287     bool PrintedGroup = false;
    288     for (const RelocationRef &Reloc : Section.relocations()) {
    289       if (!PrintedGroup) {
    290         W.startLine() << "Section " << Name << " {\n";
    291         W.indent();
    292         PrintedGroup = true;
    293       }
    294 
    295       printRelocation(Reloc);
    296     }
    297 
    298     if (PrintedGroup) {
    299       W.unindent();
    300       W.startLine() << "}\n";
    301     }
    302   }
    303 }
    304 
    305 void MachODumper::printRelocation(const RelocationRef &Reloc) {
    306   return printRelocation(Obj, Reloc);
    307 }
    308 
    309 void MachODumper::printRelocation(const MachOObjectFile *Obj,
    310                                   const RelocationRef &Reloc) {
    311   uint64_t Offset;
    312   SmallString<32> RelocName;
    313   if (error(Reloc.getOffset(Offset)))
    314     return;
    315   if (error(Reloc.getTypeName(RelocName)))
    316     return;
    317 
    318   DataRefImpl DR = Reloc.getRawDataRefImpl();
    319   MachO::any_relocation_info RE = Obj->getRelocation(DR);
    320   bool IsScattered = Obj->isRelocationScattered(RE);
    321   SmallString<32> SymbolNameOrOffset("0x");
    322   if (IsScattered) {
    323     // Scattered relocations don't really have an associated symbol
    324     // for some reason, even if one exists in the symtab at the correct address.
    325     SymbolNameOrOffset += utohexstr(Obj->getScatteredRelocationValue(RE));
    326   } else {
    327     symbol_iterator Symbol = Reloc.getSymbol();
    328     if (Symbol != Obj->symbol_end()) {
    329       StringRef SymbolName;
    330       if (error(Symbol->getName(SymbolName)))
    331         return;
    332       SymbolNameOrOffset = SymbolName;
    333     } else
    334       SymbolNameOrOffset += utohexstr(Obj->getPlainRelocationSymbolNum(RE));
    335   }
    336 
    337   if (opts::ExpandRelocs) {
    338     DictScope Group(W, "Relocation");
    339     W.printHex("Offset", Offset);
    340     W.printNumber("PCRel", Obj->getAnyRelocationPCRel(RE));
    341     W.printNumber("Length", Obj->getAnyRelocationLength(RE));
    342     if (IsScattered)
    343       W.printString("Extern", StringRef("N/A"));
    344     else
    345       W.printNumber("Extern", Obj->getPlainRelocationExternal(RE));
    346     W.printNumber("Type", RelocName, Obj->getAnyRelocationType(RE));
    347     W.printString("Symbol", SymbolNameOrOffset);
    348     W.printNumber("Scattered", IsScattered);
    349   } else {
    350     raw_ostream& OS = W.startLine();
    351     OS << W.hex(Offset)
    352        << " " << Obj->getAnyRelocationPCRel(RE)
    353        << " " << Obj->getAnyRelocationLength(RE);
    354     if (IsScattered)
    355       OS << " n/a";
    356     else
    357       OS << " " << Obj->getPlainRelocationExternal(RE);
    358     OS << " " << RelocName
    359        << " " << IsScattered
    360        << " " << SymbolNameOrOffset
    361        << "\n";
    362   }
    363 }
    364 
    365 void MachODumper::printSymbols() {
    366   ListScope Group(W, "Symbols");
    367 
    368   for (const SymbolRef &Symbol : Obj->symbols()) {
    369     printSymbol(Symbol);
    370   }
    371 }
    372 
    373 void MachODumper::printDynamicSymbols() {
    374   ListScope Group(W, "DynamicSymbols");
    375 }
    376 
    377 void MachODumper::printSymbol(const SymbolRef &Symbol) {
    378   StringRef SymbolName;
    379   if (Symbol.getName(SymbolName))
    380     SymbolName = "";
    381 
    382   MachOSymbol MOSymbol;
    383   getSymbol(Obj, Symbol.getRawDataRefImpl(), MOSymbol);
    384 
    385   StringRef SectionName = "";
    386   section_iterator SecI(Obj->section_begin());
    387   if (!error(Symbol.getSection(SecI)) && SecI != Obj->section_end())
    388     error(SecI->getName(SectionName));
    389 
    390   DictScope D(W, "Symbol");
    391   W.printNumber("Name", SymbolName, MOSymbol.StringIndex);
    392   if (MOSymbol.Type & MachO::N_STAB) {
    393     W.printHex("Type", "SymDebugTable", MOSymbol.Type);
    394   } else {
    395     if (MOSymbol.Type & MachO::N_PEXT)
    396       W.startLine() << "PrivateExtern\n";
    397     if (MOSymbol.Type & MachO::N_EXT)
    398       W.startLine() << "Extern\n";
    399     W.printEnum("Type", uint8_t(MOSymbol.Type & MachO::N_TYPE),
    400                 makeArrayRef(MachOSymbolTypes));
    401   }
    402   W.printHex("Section", SectionName, MOSymbol.SectionIndex);
    403   W.printEnum("RefType", static_cast<uint16_t>(MOSymbol.Flags & 0xF),
    404               makeArrayRef(MachOSymbolRefTypes));
    405   W.printFlags("Flags", static_cast<uint16_t>(MOSymbol.Flags & ~0xF),
    406                makeArrayRef(MachOSymbolFlags));
    407   W.printHex("Value", MOSymbol.Value);
    408 }
    409 
    410 void MachODumper::printUnwindInfo() {
    411   W.startLine() << "UnwindInfo not implemented.\n";
    412 }
    413