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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:
MachODumper(const MachOObjectFile * Obj,StreamWriter & Writer)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 
createMachODumper(const object::ObjectFile * Obj,StreamWriter & Writer,std::unique_ptr<ObjDumper> & Result)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 
getSection(const MachOObjectFile * Obj,DataRefImpl Sec,MachOSection & Section)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 
getSymbol(const MachOObjectFile * Obj,DataRefImpl DRI,MachOSymbol & Symbol)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 
printFileHeaders()207 void MachODumper::printFileHeaders() {
208   W.startLine() << "FileHeaders not implemented.\n";
209 }
210 
printSections()211 void MachODumper::printSections() {
212   return printSections(Obj);
213 }
214 
printSections(const MachOObjectFile * Obj)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 
printRelocations()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 
printRelocation(const RelocationRef & Reloc)305 void MachODumper::printRelocation(const RelocationRef &Reloc) {
306   return printRelocation(Obj, Reloc);
307 }
308 
printRelocation(const MachOObjectFile * Obj,const RelocationRef & Reloc)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 
printSymbols()365 void MachODumper::printSymbols() {
366   ListScope Group(W, "Symbols");
367 
368   for (const SymbolRef &Symbol : Obj->symbols()) {
369     printSymbol(Symbol);
370   }
371 }
372 
printDynamicSymbols()373 void MachODumper::printDynamicSymbols() {
374   ListScope Group(W, "DynamicSymbols");
375 }
376 
printSymbol(const SymbolRef & Symbol)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 
printUnwindInfo()410 void MachODumper::printUnwindInfo() {
411   W.startLine() << "UnwindInfo not implemented.\n";
412 }
413