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-objdump.
11 //
12 //===----------------------------------------------------------------------===//
13
14 #include "llvm-objdump.h"
15 #include "llvm/ADT/STLExtras.h"
16 #include "llvm/ADT/StringExtras.h"
17 #include "llvm/ADT/Triple.h"
18 #include "llvm/DebugInfo/DIContext.h"
19 #include "llvm/MC/MCAsmInfo.h"
20 #include "llvm/MC/MCContext.h"
21 #include "llvm/MC/MCDisassembler.h"
22 #include "llvm/MC/MCInst.h"
23 #include "llvm/MC/MCInstPrinter.h"
24 #include "llvm/MC/MCInstrAnalysis.h"
25 #include "llvm/MC/MCInstrDesc.h"
26 #include "llvm/MC/MCInstrInfo.h"
27 #include "llvm/MC/MCRegisterInfo.h"
28 #include "llvm/MC/MCSubtargetInfo.h"
29 #include "llvm/Object/MachO.h"
30 #include "llvm/Support/Casting.h"
31 #include "llvm/Support/CommandLine.h"
32 #include "llvm/Support/Debug.h"
33 #include "llvm/Support/Format.h"
34 #include "llvm/Support/GraphWriter.h"
35 #include "llvm/Support/MachO.h"
36 #include "llvm/Support/MemoryBuffer.h"
37 #include "llvm/Support/TargetRegistry.h"
38 #include "llvm/Support/TargetSelect.h"
39 #include "llvm/Support/raw_ostream.h"
40 #include <algorithm>
41 #include <cstring>
42 #include <system_error>
43 using namespace llvm;
44 using namespace object;
45
46 static cl::opt<bool>
47 UseDbg("g", cl::desc("Print line information from debug info if available"));
48
49 static cl::opt<std::string>
50 DSYMFile("dsym", cl::desc("Use .dSYM file for debug info"));
51
GetTarget(const MachOObjectFile * MachOObj)52 static const Target *GetTarget(const MachOObjectFile *MachOObj) {
53 // Figure out the target triple.
54 if (TripleName.empty()) {
55 llvm::Triple TT("unknown-unknown-unknown");
56 TT.setArch(Triple::ArchType(MachOObj->getArch()));
57 TripleName = TT.str();
58 }
59
60 // Get the target specific parser.
61 std::string Error;
62 const Target *TheTarget = TargetRegistry::lookupTarget(TripleName, Error);
63 if (TheTarget)
64 return TheTarget;
65
66 errs() << "llvm-objdump: error: unable to get target for '" << TripleName
67 << "', see --version and --triple.\n";
68 return nullptr;
69 }
70
71 struct SymbolSorter {
operator ()SymbolSorter72 bool operator()(const SymbolRef &A, const SymbolRef &B) {
73 SymbolRef::Type AType, BType;
74 A.getType(AType);
75 B.getType(BType);
76
77 uint64_t AAddr, BAddr;
78 if (AType != SymbolRef::ST_Function)
79 AAddr = 0;
80 else
81 A.getAddress(AAddr);
82 if (BType != SymbolRef::ST_Function)
83 BAddr = 0;
84 else
85 B.getAddress(BAddr);
86 return AAddr < BAddr;
87 }
88 };
89
90 // Types for the storted data in code table that is built before disassembly
91 // and the predicate function to sort them.
92 typedef std::pair<uint64_t, DiceRef> DiceTableEntry;
93 typedef std::vector<DiceTableEntry> DiceTable;
94 typedef DiceTable::iterator dice_table_iterator;
95
96 static bool
compareDiceTableEntries(const DiceTableEntry i,const DiceTableEntry j)97 compareDiceTableEntries(const DiceTableEntry i,
98 const DiceTableEntry j) {
99 return i.first == j.first;
100 }
101
DumpDataInCode(const char * bytes,uint64_t Size,unsigned short Kind)102 static void DumpDataInCode(const char *bytes, uint64_t Size,
103 unsigned short Kind) {
104 uint64_t Value;
105
106 switch (Kind) {
107 case MachO::DICE_KIND_DATA:
108 switch (Size) {
109 case 4:
110 Value = bytes[3] << 24 |
111 bytes[2] << 16 |
112 bytes[1] << 8 |
113 bytes[0];
114 outs() << "\t.long " << Value;
115 break;
116 case 2:
117 Value = bytes[1] << 8 |
118 bytes[0];
119 outs() << "\t.short " << Value;
120 break;
121 case 1:
122 Value = bytes[0];
123 outs() << "\t.byte " << Value;
124 break;
125 }
126 outs() << "\t@ KIND_DATA\n";
127 break;
128 case MachO::DICE_KIND_JUMP_TABLE8:
129 Value = bytes[0];
130 outs() << "\t.byte " << Value << "\t@ KIND_JUMP_TABLE8";
131 break;
132 case MachO::DICE_KIND_JUMP_TABLE16:
133 Value = bytes[1] << 8 |
134 bytes[0];
135 outs() << "\t.short " << Value << "\t@ KIND_JUMP_TABLE16";
136 break;
137 case MachO::DICE_KIND_JUMP_TABLE32:
138 Value = bytes[3] << 24 |
139 bytes[2] << 16 |
140 bytes[1] << 8 |
141 bytes[0];
142 outs() << "\t.long " << Value << "\t@ KIND_JUMP_TABLE32";
143 break;
144 default:
145 outs() << "\t@ data in code kind = " << Kind << "\n";
146 break;
147 }
148 }
149
getSectionsAndSymbols(const MachO::mach_header Header,MachOObjectFile * MachOObj,std::vector<SectionRef> & Sections,std::vector<SymbolRef> & Symbols,SmallVectorImpl<uint64_t> & FoundFns,uint64_t & BaseSegmentAddress)150 static void getSectionsAndSymbols(const MachO::mach_header Header,
151 MachOObjectFile *MachOObj,
152 std::vector<SectionRef> &Sections,
153 std::vector<SymbolRef> &Symbols,
154 SmallVectorImpl<uint64_t> &FoundFns,
155 uint64_t &BaseSegmentAddress) {
156 for (const SymbolRef &Symbol : MachOObj->symbols())
157 Symbols.push_back(Symbol);
158
159 for (const SectionRef &Section : MachOObj->sections()) {
160 StringRef SectName;
161 Section.getName(SectName);
162 Sections.push_back(Section);
163 }
164
165 MachOObjectFile::LoadCommandInfo Command =
166 MachOObj->getFirstLoadCommandInfo();
167 bool BaseSegmentAddressSet = false;
168 for (unsigned i = 0; ; ++i) {
169 if (Command.C.cmd == MachO::LC_FUNCTION_STARTS) {
170 // We found a function starts segment, parse the addresses for later
171 // consumption.
172 MachO::linkedit_data_command LLC =
173 MachOObj->getLinkeditDataLoadCommand(Command);
174
175 MachOObj->ReadULEB128s(LLC.dataoff, FoundFns);
176 }
177 else if (Command.C.cmd == MachO::LC_SEGMENT) {
178 MachO::segment_command SLC =
179 MachOObj->getSegmentLoadCommand(Command);
180 StringRef SegName = SLC.segname;
181 if(!BaseSegmentAddressSet && SegName != "__PAGEZERO") {
182 BaseSegmentAddressSet = true;
183 BaseSegmentAddress = SLC.vmaddr;
184 }
185 }
186
187 if (i == Header.ncmds - 1)
188 break;
189 else
190 Command = MachOObj->getNextLoadCommandInfo(Command);
191 }
192 }
193
194 static void DisassembleInputMachO2(StringRef Filename,
195 MachOObjectFile *MachOOF);
196
DisassembleInputMachO(StringRef Filename)197 void llvm::DisassembleInputMachO(StringRef Filename) {
198 ErrorOr<std::unique_ptr<MemoryBuffer>> Buff =
199 MemoryBuffer::getFileOrSTDIN(Filename);
200 if (std::error_code EC = Buff.getError()) {
201 errs() << "llvm-objdump: " << Filename << ": " << EC.message() << "\n";
202 return;
203 }
204
205 std::unique_ptr<MachOObjectFile> MachOOF(static_cast<MachOObjectFile *>(
206 ObjectFile::createMachOObjectFile(Buff.get()).get()));
207
208 DisassembleInputMachO2(Filename, MachOOF.get());
209 }
210
DisassembleInputMachO2(StringRef Filename,MachOObjectFile * MachOOF)211 static void DisassembleInputMachO2(StringRef Filename,
212 MachOObjectFile *MachOOF) {
213 const Target *TheTarget = GetTarget(MachOOF);
214 if (!TheTarget) {
215 // GetTarget prints out stuff.
216 return;
217 }
218 std::unique_ptr<const MCInstrInfo> InstrInfo(TheTarget->createMCInstrInfo());
219 std::unique_ptr<MCInstrAnalysis> InstrAnalysis(
220 TheTarget->createMCInstrAnalysis(InstrInfo.get()));
221
222 // Set up disassembler.
223 std::unique_ptr<const MCRegisterInfo> MRI(
224 TheTarget->createMCRegInfo(TripleName));
225 std::unique_ptr<const MCAsmInfo> AsmInfo(
226 TheTarget->createMCAsmInfo(*MRI, TripleName));
227 std::unique_ptr<const MCSubtargetInfo> STI(
228 TheTarget->createMCSubtargetInfo(TripleName, "", ""));
229 MCContext Ctx(AsmInfo.get(), MRI.get(), nullptr);
230 std::unique_ptr<const MCDisassembler> DisAsm(
231 TheTarget->createMCDisassembler(*STI, Ctx));
232 int AsmPrinterVariant = AsmInfo->getAssemblerDialect();
233 std::unique_ptr<MCInstPrinter> IP(TheTarget->createMCInstPrinter(
234 AsmPrinterVariant, *AsmInfo, *InstrInfo, *MRI, *STI));
235
236 if (!InstrAnalysis || !AsmInfo || !STI || !DisAsm || !IP) {
237 errs() << "error: couldn't initialize disassembler for target "
238 << TripleName << '\n';
239 return;
240 }
241
242 outs() << '\n' << Filename << ":\n\n";
243
244 MachO::mach_header Header = MachOOF->getHeader();
245
246 // FIXME: FoundFns isn't used anymore. Using symbols/LC_FUNCTION_STARTS to
247 // determine function locations will eventually go in MCObjectDisassembler.
248 // FIXME: Using the -cfg command line option, this code used to be able to
249 // annotate relocations with the referenced symbol's name, and if this was
250 // inside a __[cf]string section, the data it points to. This is now replaced
251 // by the upcoming MCSymbolizer, which needs the appropriate setup done above.
252 std::vector<SectionRef> Sections;
253 std::vector<SymbolRef> Symbols;
254 SmallVector<uint64_t, 8> FoundFns;
255 uint64_t BaseSegmentAddress;
256
257 getSectionsAndSymbols(Header, MachOOF, Sections, Symbols, FoundFns,
258 BaseSegmentAddress);
259
260 // Sort the symbols by address, just in case they didn't come in that way.
261 std::sort(Symbols.begin(), Symbols.end(), SymbolSorter());
262
263 // Build a data in code table that is sorted on by the address of each entry.
264 uint64_t BaseAddress = 0;
265 if (Header.filetype == MachO::MH_OBJECT)
266 Sections[0].getAddress(BaseAddress);
267 else
268 BaseAddress = BaseSegmentAddress;
269 DiceTable Dices;
270 for (dice_iterator DI = MachOOF->begin_dices(), DE = MachOOF->end_dices();
271 DI != DE; ++DI) {
272 uint32_t Offset;
273 DI->getOffset(Offset);
274 Dices.push_back(std::make_pair(BaseAddress + Offset, *DI));
275 }
276 array_pod_sort(Dices.begin(), Dices.end());
277
278 #ifndef NDEBUG
279 raw_ostream &DebugOut = DebugFlag ? dbgs() : nulls();
280 #else
281 raw_ostream &DebugOut = nulls();
282 #endif
283
284 std::unique_ptr<DIContext> diContext;
285 ObjectFile *DbgObj = MachOOF;
286 // Try to find debug info and set up the DIContext for it.
287 if (UseDbg) {
288 // A separate DSym file path was specified, parse it as a macho file,
289 // get the sections and supply it to the section name parsing machinery.
290 if (!DSYMFile.empty()) {
291 ErrorOr<std::unique_ptr<MemoryBuffer>> Buf =
292 MemoryBuffer::getFileOrSTDIN(DSYMFile);
293 if (std::error_code EC = Buf.getError()) {
294 errs() << "llvm-objdump: " << Filename << ": " << EC.message() << '\n';
295 return;
296 }
297 DbgObj = ObjectFile::createMachOObjectFile(Buf.get()).get();
298 }
299
300 // Setup the DIContext
301 diContext.reset(DIContext::getDWARFContext(DbgObj));
302 }
303
304 for (unsigned SectIdx = 0; SectIdx != Sections.size(); SectIdx++) {
305
306 bool SectIsText = false;
307 Sections[SectIdx].isText(SectIsText);
308 if (SectIsText == false)
309 continue;
310
311 StringRef SectName;
312 if (Sections[SectIdx].getName(SectName) ||
313 SectName != "__text")
314 continue; // Skip non-text sections
315
316 DataRefImpl DR = Sections[SectIdx].getRawDataRefImpl();
317
318 StringRef SegmentName = MachOOF->getSectionFinalSegmentName(DR);
319 if (SegmentName != "__TEXT")
320 continue;
321
322 StringRef Bytes;
323 Sections[SectIdx].getContents(Bytes);
324 StringRefMemoryObject memoryObject(Bytes);
325 bool symbolTableWorked = false;
326
327 // Parse relocations.
328 std::vector<std::pair<uint64_t, SymbolRef>> Relocs;
329 for (const RelocationRef &Reloc : Sections[SectIdx].relocations()) {
330 uint64_t RelocOffset, SectionAddress;
331 Reloc.getOffset(RelocOffset);
332 Sections[SectIdx].getAddress(SectionAddress);
333 RelocOffset -= SectionAddress;
334
335 symbol_iterator RelocSym = Reloc.getSymbol();
336
337 Relocs.push_back(std::make_pair(RelocOffset, *RelocSym));
338 }
339 array_pod_sort(Relocs.begin(), Relocs.end());
340
341 // Disassemble symbol by symbol.
342 for (unsigned SymIdx = 0; SymIdx != Symbols.size(); SymIdx++) {
343 StringRef SymName;
344 Symbols[SymIdx].getName(SymName);
345
346 SymbolRef::Type ST;
347 Symbols[SymIdx].getType(ST);
348 if (ST != SymbolRef::ST_Function)
349 continue;
350
351 // Make sure the symbol is defined in this section.
352 bool containsSym = false;
353 Sections[SectIdx].containsSymbol(Symbols[SymIdx], containsSym);
354 if (!containsSym)
355 continue;
356
357 // Start at the address of the symbol relative to the section's address.
358 uint64_t SectionAddress = 0;
359 uint64_t Start = 0;
360 Sections[SectIdx].getAddress(SectionAddress);
361 Symbols[SymIdx].getAddress(Start);
362 Start -= SectionAddress;
363
364 // Stop disassembling either at the beginning of the next symbol or at
365 // the end of the section.
366 bool containsNextSym = false;
367 uint64_t NextSym = 0;
368 uint64_t NextSymIdx = SymIdx+1;
369 while (Symbols.size() > NextSymIdx) {
370 SymbolRef::Type NextSymType;
371 Symbols[NextSymIdx].getType(NextSymType);
372 if (NextSymType == SymbolRef::ST_Function) {
373 Sections[SectIdx].containsSymbol(Symbols[NextSymIdx],
374 containsNextSym);
375 Symbols[NextSymIdx].getAddress(NextSym);
376 NextSym -= SectionAddress;
377 break;
378 }
379 ++NextSymIdx;
380 }
381
382 uint64_t SectSize;
383 Sections[SectIdx].getSize(SectSize);
384 uint64_t End = containsNextSym ? NextSym : SectSize;
385 uint64_t Size;
386
387 symbolTableWorked = true;
388
389 outs() << SymName << ":\n";
390 DILineInfo lastLine;
391 for (uint64_t Index = Start; Index < End; Index += Size) {
392 MCInst Inst;
393
394 uint64_t SectAddress = 0;
395 Sections[SectIdx].getAddress(SectAddress);
396 outs() << format("%8" PRIx64 ":\t", SectAddress + Index);
397
398 // Check the data in code table here to see if this is data not an
399 // instruction to be disassembled.
400 DiceTable Dice;
401 Dice.push_back(std::make_pair(SectAddress + Index, DiceRef()));
402 dice_table_iterator DTI = std::search(Dices.begin(), Dices.end(),
403 Dice.begin(), Dice.end(),
404 compareDiceTableEntries);
405 if (DTI != Dices.end()){
406 uint16_t Length;
407 DTI->second.getLength(Length);
408 DumpBytes(StringRef(Bytes.data() + Index, Length));
409 uint16_t Kind;
410 DTI->second.getKind(Kind);
411 DumpDataInCode(Bytes.data() + Index, Length, Kind);
412 continue;
413 }
414
415 if (DisAsm->getInstruction(Inst, Size, memoryObject, Index,
416 DebugOut, nulls())) {
417 DumpBytes(StringRef(Bytes.data() + Index, Size));
418 IP->printInst(&Inst, outs(), "");
419
420 // Print debug info.
421 if (diContext) {
422 DILineInfo dli =
423 diContext->getLineInfoForAddress(SectAddress + Index);
424 // Print valid line info if it changed.
425 if (dli != lastLine && dli.Line != 0)
426 outs() << "\t## " << dli.FileName << ':' << dli.Line << ':'
427 << dli.Column;
428 lastLine = dli;
429 }
430 outs() << "\n";
431 } else {
432 errs() << "llvm-objdump: warning: invalid instruction encoding\n";
433 if (Size == 0)
434 Size = 1; // skip illegible bytes
435 }
436 }
437 }
438 if (!symbolTableWorked) {
439 // Reading the symbol table didn't work, disassemble the whole section.
440 uint64_t SectAddress;
441 Sections[SectIdx].getAddress(SectAddress);
442 uint64_t SectSize;
443 Sections[SectIdx].getSize(SectSize);
444 uint64_t InstSize;
445 for (uint64_t Index = 0; Index < SectSize; Index += InstSize) {
446 MCInst Inst;
447
448 if (DisAsm->getInstruction(Inst, InstSize, memoryObject, Index,
449 DebugOut, nulls())) {
450 outs() << format("%8" PRIx64 ":\t", SectAddress + Index);
451 DumpBytes(StringRef(Bytes.data() + Index, InstSize));
452 IP->printInst(&Inst, outs(), "");
453 outs() << "\n";
454 } else {
455 errs() << "llvm-objdump: warning: invalid instruction encoding\n";
456 if (InstSize == 0)
457 InstSize = 1; // skip illegible bytes
458 }
459 }
460 }
461 }
462 }
463