xref: /llvm-project/llvm/tools/llvm-objcopy/llvm-objcopy.cpp (revision d1767dc56f5be75bdff23f3fe33e54428fed704f) 
1 //===- llvm-objcopy.cpp ---------------------------------------------------===//
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 "llvm-objcopy.h"
11 
12 #include "Object.h"
13 #include "llvm/ADT/BitmaskEnum.h"
14 #include "llvm/ADT/Optional.h"
15 #include "llvm/ADT/STLExtras.h"
16 #include "llvm/ADT/SmallVector.h"
17 #include "llvm/ADT/StringRef.h"
18 #include "llvm/ADT/Twine.h"
19 #include "llvm/BinaryFormat/ELF.h"
20 #include "llvm/Object/Archive.h"
21 #include "llvm/Object/ArchiveWriter.h"
22 #include "llvm/Object/Binary.h"
23 #include "llvm/Object/ELFObjectFile.h"
24 #include "llvm/Object/ELFTypes.h"
25 #include "llvm/Object/Error.h"
26 #include "llvm/Option/Arg.h"
27 #include "llvm/Option/ArgList.h"
28 #include "llvm/Option/Option.h"
29 #include "llvm/Support/Casting.h"
30 #include "llvm/Support/CommandLine.h"
31 #include "llvm/Support/Compiler.h"
32 #include "llvm/Support/Error.h"
33 #include "llvm/Support/ErrorHandling.h"
34 #include "llvm/Support/ErrorOr.h"
35 #include "llvm/Support/FileOutputBuffer.h"
36 #include "llvm/Support/InitLLVM.h"
37 #include "llvm/Support/Path.h"
38 #include "llvm/Support/Process.h"
39 #include "llvm/Support/WithColor.h"
40 #include "llvm/Support/raw_ostream.h"
41 #include <algorithm>
42 #include <cassert>
43 #include <cstdlib>
44 #include <functional>
45 #include <iterator>
46 #include <memory>
47 #include <string>
48 #include <system_error>
49 #include <utility>
50 
51 using namespace llvm;
52 using namespace llvm::objcopy;
53 using namespace object;
54 using namespace ELF;
55 
56 namespace {
57 
58 enum ObjcopyID {
59   OBJCOPY_INVALID = 0, // This is not an option ID.
60 #define OPTION(PREFIX, NAME, ID, KIND, GROUP, ALIAS, ALIASARGS, FLAGS, PARAM,  \
61                HELPTEXT, METAVAR, VALUES)                                      \
62   OBJCOPY_##ID,
63 #include "ObjcopyOpts.inc"
64 #undef OPTION
65 };
66 
67 #define PREFIX(NAME, VALUE) const char *const OBJCOPY_##NAME[] = VALUE;
68 #include "ObjcopyOpts.inc"
69 #undef PREFIX
70 
71 static const opt::OptTable::Info ObjcopyInfoTable[] = {
72 #define OPTION(PREFIX, NAME, ID, KIND, GROUP, ALIAS, ALIASARGS, FLAGS, PARAM,  \
73                HELPTEXT, METAVAR, VALUES)                                      \
74   {OBJCOPY_##PREFIX,                                                           \
75    NAME,                                                                       \
76    HELPTEXT,                                                                   \
77    METAVAR,                                                                    \
78    OBJCOPY_##ID,                                                               \
79    opt::Option::KIND##Class,                                                   \
80    PARAM,                                                                      \
81    FLAGS,                                                                      \
82    OBJCOPY_##GROUP,                                                            \
83    OBJCOPY_##ALIAS,                                                            \
84    ALIASARGS,                                                                  \
85    VALUES},
86 #include "ObjcopyOpts.inc"
87 #undef OPTION
88 };
89 
90 class ObjcopyOptTable : public opt::OptTable {
91 public:
92   ObjcopyOptTable() : OptTable(ObjcopyInfoTable, true) {}
93 };
94 
95 enum StripID {
96   STRIP_INVALID = 0, // This is not an option ID.
97 #define OPTION(PREFIX, NAME, ID, KIND, GROUP, ALIAS, ALIASARGS, FLAGS, PARAM,  \
98                HELPTEXT, METAVAR, VALUES)                                      \
99   STRIP_##ID,
100 #include "StripOpts.inc"
101 #undef OPTION
102 };
103 
104 #define PREFIX(NAME, VALUE) const char *const STRIP_##NAME[] = VALUE;
105 #include "StripOpts.inc"
106 #undef PREFIX
107 
108 static const opt::OptTable::Info StripInfoTable[] = {
109 #define OPTION(PREFIX, NAME, ID, KIND, GROUP, ALIAS, ALIASARGS, FLAGS, PARAM,  \
110                HELPTEXT, METAVAR, VALUES)                                      \
111   {STRIP_##PREFIX, NAME,       HELPTEXT,                                       \
112    METAVAR,        STRIP_##ID, opt::Option::KIND##Class,                       \
113    PARAM,          FLAGS,      STRIP_##GROUP,                                  \
114    STRIP_##ALIAS,  ALIASARGS,  VALUES},
115 #include "StripOpts.inc"
116 #undef OPTION
117 };
118 
119 class StripOptTable : public opt::OptTable {
120 public:
121   StripOptTable() : OptTable(StripInfoTable, true) {}
122 };
123 
124 struct SectionRename {
125   StringRef OriginalName;
126   StringRef NewName;
127   Optional<uint64_t> NewFlags;
128 };
129 
130 struct CopyConfig {
131   StringRef OutputFilename;
132   StringRef InputFilename;
133   StringRef OutputFormat;
134   StringRef InputFormat;
135   StringRef BinaryArch;
136 
137   StringRef SplitDWO;
138   StringRef AddGnuDebugLink;
139   StringRef SymbolsPrefix;
140   std::vector<StringRef> ToRemove;
141   std::vector<StringRef> Keep;
142   std::vector<StringRef> OnlyKeep;
143   std::vector<StringRef> AddSection;
144   std::vector<StringRef> DumpSection;
145   std::vector<StringRef> SymbolsToLocalize;
146   std::vector<StringRef> SymbolsToGlobalize;
147   std::vector<StringRef> SymbolsToWeaken;
148   std::vector<StringRef> SymbolsToRemove;
149   std::vector<StringRef> SymbolsToKeep;
150   StringMap<SectionRename> SectionsToRename;
151   StringMap<StringRef> SymbolsToRename;
152   bool StripAll = false;
153   bool StripAllGNU = false;
154   bool StripDebug = false;
155   bool StripSections = false;
156   bool StripNonAlloc = false;
157   bool StripDWO = false;
158   bool StripUnneeded = false;
159   bool ExtractDWO = false;
160   bool LocalizeHidden = false;
161   bool Weaken = false;
162   bool DiscardAll = false;
163   bool OnlyKeepDebug = false;
164   bool KeepFileSymbols = false;
165   bool PreserveDates = false;
166 };
167 
168 using SectionPred = std::function<bool(const SectionBase &Sec)>;
169 
170 enum SectionFlag {
171   SecNone = 0,
172   SecAlloc = 1 << 0,
173   SecLoad = 1 << 1,
174   SecNoload = 1 << 2,
175   SecReadonly = 1 << 3,
176   SecDebug = 1 << 4,
177   SecCode = 1 << 5,
178   SecData = 1 << 6,
179   SecRom = 1 << 7,
180   SecMerge = 1 << 8,
181   SecStrings = 1 << 9,
182   SecContents = 1 << 10,
183   SecShare = 1 << 11,
184   LLVM_MARK_AS_BITMASK_ENUM(/* LargestValue = */ SecShare)
185 };
186 
187 } // namespace
188 
189 namespace llvm {
190 namespace objcopy {
191 
192 // The name this program was invoked as.
193 StringRef ToolName;
194 
195 LLVM_ATTRIBUTE_NORETURN void error(Twine Message) {
196   WithColor::error(errs(), ToolName) << Message << ".\n";
197   errs().flush();
198   exit(1);
199 }
200 
201 LLVM_ATTRIBUTE_NORETURN void reportError(StringRef File, std::error_code EC) {
202   assert(EC);
203   WithColor::error(errs(), ToolName)
204       << "'" << File << "': " << EC.message() << ".\n";
205   exit(1);
206 }
207 
208 LLVM_ATTRIBUTE_NORETURN void reportError(StringRef File, Error E) {
209   assert(E);
210   std::string Buf;
211   raw_string_ostream OS(Buf);
212   logAllUnhandledErrors(std::move(E), OS, "");
213   OS.flush();
214   WithColor::error(errs(), ToolName) << "'" << File << "': " << Buf;
215   exit(1);
216 }
217 
218 } // end namespace objcopy
219 } // end namespace llvm
220 
221 static SectionFlag parseSectionRenameFlag(StringRef SectionName) {
222   return llvm::StringSwitch<SectionFlag>(SectionName)
223       .Case("alloc", SectionFlag::SecAlloc)
224       .Case("load", SectionFlag::SecLoad)
225       .Case("noload", SectionFlag::SecNoload)
226       .Case("readonly", SectionFlag::SecReadonly)
227       .Case("debug", SectionFlag::SecDebug)
228       .Case("code", SectionFlag::SecCode)
229       .Case("data", SectionFlag::SecData)
230       .Case("rom", SectionFlag::SecRom)
231       .Case("merge", SectionFlag::SecMerge)
232       .Case("strings", SectionFlag::SecStrings)
233       .Case("contents", SectionFlag::SecContents)
234       .Case("share", SectionFlag::SecShare)
235       .Default(SectionFlag::SecNone);
236 }
237 
238 static SectionRename parseRenameSectionValue(StringRef FlagValue) {
239   if (!FlagValue.contains('='))
240     error("Bad format for --rename-section: missing '='");
241 
242   // Initial split: ".foo" = ".bar,f1,f2,..."
243   auto Old2New = FlagValue.split('=');
244   SectionRename SR;
245   SR.OriginalName = Old2New.first;
246 
247   // Flags split: ".bar" "f1" "f2" ...
248   SmallVector<StringRef, 6> NameAndFlags;
249   Old2New.second.split(NameAndFlags, ',');
250   SR.NewName = NameAndFlags[0];
251 
252   if (NameAndFlags.size() > 1) {
253     SectionFlag Flags = SectionFlag::SecNone;
254     for (size_t I = 1, Size = NameAndFlags.size(); I < Size; ++I) {
255       SectionFlag Flag = parseSectionRenameFlag(NameAndFlags[I]);
256       if (Flag == SectionFlag::SecNone)
257         error("Unrecognized section flag '" + NameAndFlags[I] +
258               "'. Flags supported for GNU compatibility: alloc, load, noload, "
259               "readonly, debug, code, data, rom, share, contents, merge, "
260               "strings.");
261       Flags |= Flag;
262     }
263 
264     SR.NewFlags = 0;
265     if (Flags & SectionFlag::SecAlloc)
266       *SR.NewFlags |= ELF::SHF_ALLOC;
267     if (!(Flags & SectionFlag::SecReadonly))
268       *SR.NewFlags |= ELF::SHF_WRITE;
269     if (Flags & SectionFlag::SecCode)
270       *SR.NewFlags |= ELF::SHF_EXECINSTR;
271     if (Flags & SectionFlag::SecMerge)
272       *SR.NewFlags |= ELF::SHF_MERGE;
273     if (Flags & SectionFlag::SecStrings)
274       *SR.NewFlags |= ELF::SHF_STRINGS;
275   }
276 
277   return SR;
278 }
279 
280 static bool isDebugSection(const SectionBase &Sec) {
281   return Sec.Name.startswith(".debug") || Sec.Name.startswith(".zdebug") ||
282          Sec.Name == ".gdb_index";
283 }
284 
285 static bool isDWOSection(const SectionBase &Sec) {
286   return Sec.Name.endswith(".dwo");
287 }
288 
289 static bool onlyKeepDWOPred(const Object &Obj, const SectionBase &Sec) {
290   // We can't remove the section header string table.
291   if (&Sec == Obj.SectionNames)
292     return false;
293   // Short of keeping the string table we want to keep everything that is a DWO
294   // section and remove everything else.
295   return !isDWOSection(Sec);
296 }
297 
298 static std::unique_ptr<Writer> createWriter(const CopyConfig &Config,
299                                             Object &Obj, Buffer &Buf,
300                                             ElfType OutputElfType) {
301   if (Config.OutputFormat == "binary") {
302     return llvm::make_unique<BinaryWriter>(Obj, Buf);
303   }
304   // Depending on the initial ELFT and OutputFormat we need a different Writer.
305   switch (OutputElfType) {
306   case ELFT_ELF32LE:
307     return llvm::make_unique<ELFWriter<ELF32LE>>(Obj, Buf,
308                                                  !Config.StripSections);
309   case ELFT_ELF64LE:
310     return llvm::make_unique<ELFWriter<ELF64LE>>(Obj, Buf,
311                                                  !Config.StripSections);
312   case ELFT_ELF32BE:
313     return llvm::make_unique<ELFWriter<ELF32BE>>(Obj, Buf,
314                                                  !Config.StripSections);
315   case ELFT_ELF64BE:
316     return llvm::make_unique<ELFWriter<ELF64BE>>(Obj, Buf,
317                                                  !Config.StripSections);
318   }
319   llvm_unreachable("Invalid output format");
320 }
321 
322 static void splitDWOToFile(const CopyConfig &Config, const Reader &Reader,
323                            StringRef File, ElfType OutputElfType) {
324   auto DWOFile = Reader.create();
325   DWOFile->removeSections(
326       [&](const SectionBase &Sec) { return onlyKeepDWOPred(*DWOFile, Sec); });
327   FileBuffer FB(File);
328   auto Writer = createWriter(Config, *DWOFile, FB, OutputElfType);
329   Writer->finalize();
330   Writer->write();
331 }
332 
333 static Error dumpSectionToFile(StringRef SecName, StringRef Filename,
334                                Object &Obj) {
335   for (auto &Sec : Obj.sections()) {
336     if (Sec.Name == SecName) {
337       if (Sec.OriginalData.size() == 0)
338         return make_error<StringError>("Can't dump section \"" + SecName +
339                                            "\": it has no contents",
340                                        object_error::parse_failed);
341       Expected<std::unique_ptr<FileOutputBuffer>> BufferOrErr =
342           FileOutputBuffer::create(Filename, Sec.OriginalData.size());
343       if (!BufferOrErr)
344         return BufferOrErr.takeError();
345       std::unique_ptr<FileOutputBuffer> Buf = std::move(*BufferOrErr);
346       std::copy(Sec.OriginalData.begin(), Sec.OriginalData.end(),
347                 Buf->getBufferStart());
348       if (Error E = Buf->commit())
349         return E;
350       return Error::success();
351     }
352   }
353   return make_error<StringError>("Section not found",
354                                  object_error::parse_failed);
355 }
356 
357 // This function handles the high level operations of GNU objcopy including
358 // handling command line options. It's important to outline certain properties
359 // we expect to hold of the command line operations. Any operation that "keeps"
360 // should keep regardless of a remove. Additionally any removal should respect
361 // any previous removals. Lastly whether or not something is removed shouldn't
362 // depend a) on the order the options occur in or b) on some opaque priority
363 // system. The only priority is that keeps/copies overrule removes.
364 static void handleArgs(const CopyConfig &Config, Object &Obj,
365                        const Reader &Reader, ElfType OutputElfType) {
366 
367   if (!Config.SplitDWO.empty()) {
368     splitDWOToFile(Config, Reader, Config.SplitDWO, OutputElfType);
369   }
370 
371   // TODO: update or remove symbols only if there is an option that affects
372   // them.
373   if (Obj.SymbolTable) {
374     Obj.SymbolTable->updateSymbols([&](Symbol &Sym) {
375       if ((Config.LocalizeHidden &&
376            (Sym.Visibility == STV_HIDDEN || Sym.Visibility == STV_INTERNAL)) ||
377           (!Config.SymbolsToLocalize.empty() &&
378            is_contained(Config.SymbolsToLocalize, Sym.Name)))
379         Sym.Binding = STB_LOCAL;
380 
381       if (!Config.SymbolsToGlobalize.empty() &&
382           is_contained(Config.SymbolsToGlobalize, Sym.Name))
383         Sym.Binding = STB_GLOBAL;
384 
385       if (!Config.SymbolsToWeaken.empty() &&
386           is_contained(Config.SymbolsToWeaken, Sym.Name) &&
387           Sym.Binding == STB_GLOBAL)
388         Sym.Binding = STB_WEAK;
389 
390       if (Config.Weaken && Sym.Binding == STB_GLOBAL &&
391           Sym.getShndx() != SHN_UNDEF)
392         Sym.Binding = STB_WEAK;
393 
394       const auto I = Config.SymbolsToRename.find(Sym.Name);
395       if (I != Config.SymbolsToRename.end())
396         Sym.Name = I->getValue();
397 
398       if (!Config.SymbolsPrefix.empty() && Sym.Type != STT_SECTION)
399         Sym.Name = (Config.SymbolsPrefix + Sym.Name).str();
400     });
401 
402     // The purpose of this loop is to mark symbols referenced by sections
403     // (like GroupSection or RelocationSection). This way, we know which
404     // symbols are still 'needed' and wich are not.
405     if (Config.StripUnneeded) {
406       for (auto &Section : Obj.sections())
407         Section.markSymbols();
408     }
409 
410     Obj.removeSymbols([&](const Symbol &Sym) {
411       if ((!Config.SymbolsToKeep.empty() &&
412            is_contained(Config.SymbolsToKeep, Sym.Name)) ||
413           (Config.KeepFileSymbols && Sym.Type == STT_FILE))
414         return false;
415 
416       if (Config.DiscardAll && Sym.Binding == STB_LOCAL &&
417           Sym.getShndx() != SHN_UNDEF && Sym.Type != STT_FILE &&
418           Sym.Type != STT_SECTION)
419         return true;
420 
421       if (Config.StripAll || Config.StripAllGNU)
422         return true;
423 
424       if (!Config.SymbolsToRemove.empty() &&
425           is_contained(Config.SymbolsToRemove, Sym.Name)) {
426         return true;
427       }
428 
429       if (Config.StripUnneeded && !Sym.Referenced &&
430           (Sym.Binding == STB_LOCAL || Sym.getShndx() == SHN_UNDEF) &&
431           Sym.Type != STT_FILE && Sym.Type != STT_SECTION)
432         return true;
433 
434       return false;
435     });
436   }
437 
438   SectionPred RemovePred = [](const SectionBase &) { return false; };
439 
440   // Removes:
441   if (!Config.ToRemove.empty()) {
442     RemovePred = [&Config](const SectionBase &Sec) {
443       return find(Config.ToRemove, Sec.Name) != Config.ToRemove.end();
444     };
445   }
446 
447   if (Config.StripDWO || !Config.SplitDWO.empty())
448     RemovePred = [RemovePred](const SectionBase &Sec) {
449       return isDWOSection(Sec) || RemovePred(Sec);
450     };
451 
452   if (Config.ExtractDWO)
453     RemovePred = [RemovePred, &Obj](const SectionBase &Sec) {
454       return onlyKeepDWOPred(Obj, Sec) || RemovePred(Sec);
455     };
456 
457   if (Config.StripAllGNU)
458     RemovePred = [RemovePred, &Obj](const SectionBase &Sec) {
459       if (RemovePred(Sec))
460         return true;
461       if ((Sec.Flags & SHF_ALLOC) != 0)
462         return false;
463       if (&Sec == Obj.SectionNames)
464         return false;
465       switch (Sec.Type) {
466       case SHT_SYMTAB:
467       case SHT_REL:
468       case SHT_RELA:
469       case SHT_STRTAB:
470         return true;
471       }
472       return isDebugSection(Sec);
473     };
474 
475   if (Config.StripSections) {
476     RemovePred = [RemovePred](const SectionBase &Sec) {
477       return RemovePred(Sec) || (Sec.Flags & SHF_ALLOC) == 0;
478     };
479   }
480 
481   if (Config.StripDebug) {
482     RemovePred = [RemovePred](const SectionBase &Sec) {
483       return RemovePred(Sec) || isDebugSection(Sec);
484     };
485   }
486 
487   if (Config.StripNonAlloc)
488     RemovePred = [RemovePred, &Obj](const SectionBase &Sec) {
489       if (RemovePred(Sec))
490         return true;
491       if (&Sec == Obj.SectionNames)
492         return false;
493       return (Sec.Flags & SHF_ALLOC) == 0;
494     };
495 
496   if (Config.StripAll)
497     RemovePred = [RemovePred, &Obj](const SectionBase &Sec) {
498       if (RemovePred(Sec))
499         return true;
500       if (&Sec == Obj.SectionNames)
501         return false;
502       if (Sec.Name.startswith(".gnu.warning"))
503         return false;
504       return (Sec.Flags & SHF_ALLOC) == 0;
505     };
506 
507   // Explicit copies:
508   if (!Config.OnlyKeep.empty()) {
509     RemovePred = [&Config, RemovePred, &Obj](const SectionBase &Sec) {
510       // Explicitly keep these sections regardless of previous removes.
511       if (find(Config.OnlyKeep, Sec.Name) != Config.OnlyKeep.end())
512         return false;
513 
514       // Allow all implicit removes.
515       if (RemovePred(Sec))
516         return true;
517 
518       // Keep special sections.
519       if (Obj.SectionNames == &Sec)
520         return false;
521       if (Obj.SymbolTable == &Sec ||
522           (Obj.SymbolTable && Obj.SymbolTable->getStrTab() == &Sec))
523         return false;
524 
525       // Remove everything else.
526       return true;
527     };
528   }
529 
530   if (!Config.Keep.empty()) {
531     RemovePred = [Config, RemovePred](const SectionBase &Sec) {
532       // Explicitly keep these sections regardless of previous removes.
533       if (find(Config.Keep, Sec.Name) != Config.Keep.end())
534         return false;
535       // Otherwise defer to RemovePred.
536       return RemovePred(Sec);
537     };
538   }
539 
540   // This has to be the last predicate assignment.
541   // If the option --keep-symbol has been specified
542   // and at least one of those symbols is present
543   // (equivalently, the updated symbol table is not empty)
544   // the symbol table and the string table should not be removed.
545   if ((!Config.SymbolsToKeep.empty() || Config.KeepFileSymbols) &&
546       Obj.SymbolTable && !Obj.SymbolTable->empty()) {
547     RemovePred = [&Obj, RemovePred](const SectionBase &Sec) {
548       if (&Sec == Obj.SymbolTable || &Sec == Obj.SymbolTable->getStrTab())
549         return false;
550       return RemovePred(Sec);
551     };
552   }
553 
554   Obj.removeSections(RemovePred);
555 
556   if (!Config.SectionsToRename.empty()) {
557     for (auto &Sec : Obj.sections()) {
558       const auto Iter = Config.SectionsToRename.find(Sec.Name);
559       if (Iter != Config.SectionsToRename.end()) {
560         const SectionRename &SR = Iter->second;
561         Sec.Name = SR.NewName;
562         if (SR.NewFlags.hasValue()) {
563           // Preserve some flags which should not be dropped when setting flags.
564           // Also, preserve anything OS/processor dependant.
565           const uint64_t PreserveMask = ELF::SHF_COMPRESSED | ELF::SHF_EXCLUDE |
566                                         ELF::SHF_GROUP | ELF::SHF_LINK_ORDER |
567                                         ELF::SHF_MASKOS | ELF::SHF_MASKPROC |
568                                         ELF::SHF_TLS | ELF::SHF_INFO_LINK;
569           Sec.Flags = (Sec.Flags & PreserveMask) |
570                       (SR.NewFlags.getValue() & ~PreserveMask);
571         }
572       }
573     }
574   }
575 
576   if (!Config.AddSection.empty()) {
577     for (const auto &Flag : Config.AddSection) {
578       auto SecPair = Flag.split("=");
579       auto SecName = SecPair.first;
580       auto File = SecPair.second;
581       auto BufOrErr = MemoryBuffer::getFile(File);
582       if (!BufOrErr)
583         reportError(File, BufOrErr.getError());
584       auto Buf = std::move(*BufOrErr);
585       auto BufPtr = reinterpret_cast<const uint8_t *>(Buf->getBufferStart());
586       auto BufSize = Buf->getBufferSize();
587       Obj.addSection<OwnedDataSection>(SecName,
588                                        ArrayRef<uint8_t>(BufPtr, BufSize));
589     }
590   }
591 
592   if (!Config.DumpSection.empty()) {
593     for (const auto &Flag : Config.DumpSection) {
594       std::pair<StringRef, StringRef> SecPair = Flag.split("=");
595       StringRef SecName = SecPair.first;
596       StringRef File = SecPair.second;
597       if (Error E = dumpSectionToFile(SecName, File, Obj))
598         reportError(Config.InputFilename, std::move(E));
599     }
600   }
601 
602   if (!Config.AddGnuDebugLink.empty())
603     Obj.addSection<GnuDebugLinkSection>(Config.AddGnuDebugLink);
604 }
605 
606 static void executeElfObjcopyOnBinary(const CopyConfig &Config, Binary &Binary,
607                                       Buffer &Out) {
608   ELFReader Reader(&Binary);
609   std::unique_ptr<Object> Obj = Reader.create();
610 
611   handleArgs(Config, *Obj, Reader, Reader.getElfType());
612 
613   std::unique_ptr<Writer> Writer =
614       createWriter(Config, *Obj, Out, Reader.getElfType());
615   Writer->finalize();
616   Writer->write();
617 }
618 
619 // For regular archives this function simply calls llvm::writeArchive,
620 // For thin archives it writes the archive file itself as well as its members.
621 static Error deepWriteArchive(StringRef ArcName,
622                               ArrayRef<NewArchiveMember> NewMembers,
623                               bool WriteSymtab, object::Archive::Kind Kind,
624                               bool Deterministic, bool Thin) {
625   Error E =
626       writeArchive(ArcName, NewMembers, WriteSymtab, Kind, Deterministic, Thin);
627   if (!Thin || E)
628     return E;
629   for (const NewArchiveMember &Member : NewMembers) {
630     // Internally, FileBuffer will use the buffer created by
631     // FileOutputBuffer::create, for regular files (that is the case for
632     // deepWriteArchive) FileOutputBuffer::create will return OnDiskBuffer.
633     // OnDiskBuffer uses a temporary file and then renames it. So in reality
634     // there is no inefficiency / duplicated in-memory buffers in this case. For
635     // now in-memory buffers can not be completely avoided since
636     // NewArchiveMember still requires them even though writeArchive does not
637     // write them on disk.
638     FileBuffer FB(Member.MemberName);
639     FB.allocate(Member.Buf->getBufferSize());
640     std::copy(Member.Buf->getBufferStart(), Member.Buf->getBufferEnd(),
641               FB.getBufferStart());
642     if (auto E = FB.commit())
643       return E;
644   }
645   return Error::success();
646 }
647 
648 static void executeElfObjcopyOnArchive(const CopyConfig &Config,
649                                        const Archive &Ar) {
650   std::vector<NewArchiveMember> NewArchiveMembers;
651   Error Err = Error::success();
652   for (const Archive::Child &Child : Ar.children(Err)) {
653     Expected<std::unique_ptr<Binary>> ChildOrErr = Child.getAsBinary();
654     if (!ChildOrErr)
655       reportError(Ar.getFileName(), ChildOrErr.takeError());
656     Expected<StringRef> ChildNameOrErr = Child.getName();
657     if (!ChildNameOrErr)
658       reportError(Ar.getFileName(), ChildNameOrErr.takeError());
659 
660     MemBuffer MB(ChildNameOrErr.get());
661     executeElfObjcopyOnBinary(Config, **ChildOrErr, MB);
662 
663     Expected<NewArchiveMember> Member =
664         NewArchiveMember::getOldMember(Child, true);
665     if (!Member)
666       reportError(Ar.getFileName(), Member.takeError());
667     Member->Buf = MB.releaseMemoryBuffer();
668     Member->MemberName = Member->Buf->getBufferIdentifier();
669     NewArchiveMembers.push_back(std::move(*Member));
670   }
671 
672   if (Err)
673     reportError(Config.InputFilename, std::move(Err));
674   if (Error E =
675           deepWriteArchive(Config.OutputFilename, NewArchiveMembers,
676                            Ar.hasSymbolTable(), Ar.kind(), true, Ar.isThin()))
677     reportError(Config.OutputFilename, std::move(E));
678 }
679 
680 static void restoreDateOnFile(StringRef Filename,
681                               const sys::fs::file_status &Stat) {
682   int FD;
683 
684   if (auto EC = sys::fs::openFileForWrite(Filename, FD))
685     reportError(Filename, EC);
686 
687   if (auto EC = sys::fs::setLastAccessAndModificationTime(
688           FD, Stat.getLastAccessedTime(), Stat.getLastModificationTime()))
689     reportError(Filename, EC);
690 
691   if (auto EC = sys::Process::SafelyCloseFileDescriptor(FD))
692     reportError(Filename, EC);
693 }
694 
695 static void executeElfObjcopy(const CopyConfig &Config) {
696   sys::fs::file_status Stat;
697   if (Config.PreserveDates)
698     if (auto EC = sys::fs::status(Config.InputFilename, Stat))
699       reportError(Config.InputFilename, EC);
700 
701   Expected<OwningBinary<llvm::object::Binary>> BinaryOrErr =
702       createBinary(Config.InputFilename);
703   if (!BinaryOrErr)
704     reportError(Config.InputFilename, BinaryOrErr.takeError());
705 
706   if (Archive *Ar = dyn_cast<Archive>(BinaryOrErr.get().getBinary())) {
707     executeElfObjcopyOnArchive(Config, *Ar);
708   } else {
709     FileBuffer FB(Config.OutputFilename);
710     executeElfObjcopyOnBinary(Config, *BinaryOrErr.get().getBinary(), FB);
711   }
712 
713   if (Config.PreserveDates) {
714     restoreDateOnFile(Config.OutputFilename, Stat);
715     if (!Config.SplitDWO.empty())
716       restoreDateOnFile(Config.SplitDWO, Stat);
717   }
718 }
719 
720 // ParseObjcopyOptions returns the config and sets the input arguments. If a
721 // help flag is set then ParseObjcopyOptions will print the help messege and
722 // exit.
723 static CopyConfig parseObjcopyOptions(ArrayRef<const char *> ArgsArr) {
724   ObjcopyOptTable T;
725   unsigned MissingArgumentIndex, MissingArgumentCount;
726   llvm::opt::InputArgList InputArgs =
727       T.ParseArgs(ArgsArr, MissingArgumentIndex, MissingArgumentCount);
728 
729   if (InputArgs.size() == 0) {
730     T.PrintHelp(errs(), "llvm-objcopy <input> [ <output> ]", "objcopy tool");
731     exit(1);
732   }
733 
734   if (InputArgs.hasArg(OBJCOPY_help)) {
735     T.PrintHelp(outs(), "llvm-objcopy <input> [ <output> ]", "objcopy tool");
736     exit(0);
737   }
738 
739   SmallVector<const char *, 2> Positional;
740 
741   for (auto Arg : InputArgs.filtered(OBJCOPY_UNKNOWN))
742     error("unknown argument '" + Arg->getAsString(InputArgs) + "'");
743 
744   for (auto Arg : InputArgs.filtered(OBJCOPY_INPUT))
745     Positional.push_back(Arg->getValue());
746 
747   if (Positional.empty())
748     error("No input file specified");
749 
750   if (Positional.size() > 2)
751     error("Too many positional arguments");
752 
753   CopyConfig Config;
754   Config.InputFilename = Positional[0];
755   Config.OutputFilename = Positional[Positional.size() == 1 ? 0 : 1];
756   Config.InputFormat = InputArgs.getLastArgValue(OBJCOPY_input_target);
757   Config.OutputFormat = InputArgs.getLastArgValue(OBJCOPY_output_target);
758   Config.BinaryArch = InputArgs.getLastArgValue(OBJCOPY_binary_architecture);
759 
760   Config.SplitDWO = InputArgs.getLastArgValue(OBJCOPY_split_dwo);
761   Config.AddGnuDebugLink = InputArgs.getLastArgValue(OBJCOPY_add_gnu_debuglink);
762   Config.SymbolsPrefix = InputArgs.getLastArgValue(OBJCOPY_prefix_symbols);
763 
764   for (auto Arg : InputArgs.filtered(OBJCOPY_redefine_symbol)) {
765     if (!StringRef(Arg->getValue()).contains('='))
766       error("Bad format for --redefine-sym");
767     auto Old2New = StringRef(Arg->getValue()).split('=');
768     if (!Config.SymbolsToRename.insert(Old2New).second)
769       error("Multiple redefinition of symbol " + Old2New.first);
770   }
771 
772   for (auto Arg : InputArgs.filtered(OBJCOPY_rename_section)) {
773     SectionRename SR = parseRenameSectionValue(StringRef(Arg->getValue()));
774     if (!Config.SectionsToRename.try_emplace(SR.OriginalName, SR).second)
775       error("Multiple renames of section " + SR.OriginalName);
776   }
777 
778   for (auto Arg : InputArgs.filtered(OBJCOPY_remove_section))
779     Config.ToRemove.push_back(Arg->getValue());
780   for (auto Arg : InputArgs.filtered(OBJCOPY_keep))
781     Config.Keep.push_back(Arg->getValue());
782   for (auto Arg : InputArgs.filtered(OBJCOPY_only_keep))
783     Config.OnlyKeep.push_back(Arg->getValue());
784   for (auto Arg : InputArgs.filtered(OBJCOPY_add_section))
785     Config.AddSection.push_back(Arg->getValue());
786   for (auto Arg : InputArgs.filtered(OBJCOPY_dump_section))
787     Config.DumpSection.push_back(Arg->getValue());
788   Config.StripAll = InputArgs.hasArg(OBJCOPY_strip_all);
789   Config.StripAllGNU = InputArgs.hasArg(OBJCOPY_strip_all_gnu);
790   Config.StripDebug = InputArgs.hasArg(OBJCOPY_strip_debug);
791   Config.StripDWO = InputArgs.hasArg(OBJCOPY_strip_dwo);
792   Config.StripSections = InputArgs.hasArg(OBJCOPY_strip_sections);
793   Config.StripNonAlloc = InputArgs.hasArg(OBJCOPY_strip_non_alloc);
794   Config.StripUnneeded = InputArgs.hasArg(OBJCOPY_strip_unneeded);
795   Config.ExtractDWO = InputArgs.hasArg(OBJCOPY_extract_dwo);
796   Config.LocalizeHidden = InputArgs.hasArg(OBJCOPY_localize_hidden);
797   Config.Weaken = InputArgs.hasArg(OBJCOPY_weaken);
798   Config.DiscardAll = InputArgs.hasArg(OBJCOPY_discard_all);
799   Config.OnlyKeepDebug = InputArgs.hasArg(OBJCOPY_only_keep_debug);
800   Config.KeepFileSymbols = InputArgs.hasArg(OBJCOPY_keep_file_symbols);
801   for (auto Arg : InputArgs.filtered(OBJCOPY_localize_symbol))
802     Config.SymbolsToLocalize.push_back(Arg->getValue());
803   for (auto Arg : InputArgs.filtered(OBJCOPY_globalize_symbol))
804     Config.SymbolsToGlobalize.push_back(Arg->getValue());
805   for (auto Arg : InputArgs.filtered(OBJCOPY_weaken_symbol))
806     Config.SymbolsToWeaken.push_back(Arg->getValue());
807   for (auto Arg : InputArgs.filtered(OBJCOPY_strip_symbol))
808     Config.SymbolsToRemove.push_back(Arg->getValue());
809   for (auto Arg : InputArgs.filtered(OBJCOPY_keep_symbol))
810     Config.SymbolsToKeep.push_back(Arg->getValue());
811 
812   Config.PreserveDates = InputArgs.hasArg(OBJCOPY_preserve_dates);
813 
814   return Config;
815 }
816 
817 // ParseStripOptions returns the config and sets the input arguments. If a
818 // help flag is set then ParseStripOptions will print the help messege and
819 // exit.
820 static CopyConfig parseStripOptions(ArrayRef<const char *> ArgsArr) {
821   StripOptTable T;
822   unsigned MissingArgumentIndex, MissingArgumentCount;
823   llvm::opt::InputArgList InputArgs =
824       T.ParseArgs(ArgsArr, MissingArgumentIndex, MissingArgumentCount);
825 
826   if (InputArgs.size() == 0) {
827     T.PrintHelp(errs(), "llvm-strip <input> [ <output> ]", "strip tool");
828     exit(1);
829   }
830 
831   if (InputArgs.hasArg(STRIP_help)) {
832     T.PrintHelp(outs(), "llvm-strip <input> [ <output> ]", "strip tool");
833     exit(0);
834   }
835 
836   SmallVector<const char *, 2> Positional;
837   for (auto Arg : InputArgs.filtered(STRIP_UNKNOWN))
838     error("unknown argument '" + Arg->getAsString(InputArgs) + "'");
839   for (auto Arg : InputArgs.filtered(STRIP_INPUT))
840     Positional.push_back(Arg->getValue());
841 
842   if (Positional.empty())
843     error("No input file specified");
844 
845   if (Positional.size() > 2)
846     error("Support for multiple input files is not implemented yet");
847 
848   CopyConfig Config;
849   Config.InputFilename = Positional[0];
850   Config.OutputFilename =
851       InputArgs.getLastArgValue(STRIP_output, Positional[0]);
852 
853   Config.StripDebug = InputArgs.hasArg(STRIP_strip_debug);
854 
855   Config.DiscardAll = InputArgs.hasArg(STRIP_discard_all);
856   Config.StripUnneeded = InputArgs.hasArg(STRIP_strip_unneeded);
857   Config.StripAll = InputArgs.hasArg(STRIP_strip_all);
858 
859   if (!Config.StripDebug && !Config.StripUnneeded && !Config.DiscardAll)
860     Config.StripAll = true;
861 
862   for (auto Arg : InputArgs.filtered(STRIP_remove_section))
863     Config.ToRemove.push_back(Arg->getValue());
864 
865   for (auto Arg : InputArgs.filtered(STRIP_keep_symbol))
866     Config.SymbolsToKeep.push_back(Arg->getValue());
867 
868   Config.PreserveDates = InputArgs.hasArg(STRIP_preserve_dates);
869 
870   return Config;
871 }
872 
873 int main(int argc, char **argv) {
874   InitLLVM X(argc, argv);
875   ToolName = argv[0];
876   CopyConfig Config;
877   if (sys::path::stem(ToolName).endswith_lower("strip"))
878     Config = parseStripOptions(makeArrayRef(argv + 1, argc));
879   else
880     Config = parseObjcopyOptions(makeArrayRef(argv + 1, argc));
881   executeElfObjcopy(Config);
882 }
883