xref: /llvm-project/llvm/tools/llvm-objcopy/llvm-objcopy.cpp (revision 29407f3abe1632df8acb8c578501da1165b251bd) 
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 #include "Object.h"
12 #include "llvm/ADT/STLExtras.h"
13 #include "llvm/ADT/StringRef.h"
14 #include "llvm/ADT/Twine.h"
15 #include "llvm/BinaryFormat/ELF.h"
16 #include "llvm/Object/Binary.h"
17 #include "llvm/Object/ELFObjectFile.h"
18 #include "llvm/Object/ELFTypes.h"
19 #include "llvm/Object/Error.h"
20 #include "llvm/Option/Arg.h"
21 #include "llvm/Option/ArgList.h"
22 #include "llvm/Option/Option.h"
23 #include "llvm/Support/Casting.h"
24 #include "llvm/Support/CommandLine.h"
25 #include "llvm/Support/Compiler.h"
26 #include "llvm/Support/Error.h"
27 #include "llvm/Support/ErrorHandling.h"
28 #include "llvm/Support/ErrorOr.h"
29 #include "llvm/Support/FileOutputBuffer.h"
30 #include "llvm/Support/InitLLVM.h"
31 #include "llvm/Support/Path.h"
32 #include "llvm/Support/raw_ostream.h"
33 #include <algorithm>
34 #include <cassert>
35 #include <cstdlib>
36 #include <functional>
37 #include <iterator>
38 #include <memory>
39 #include <string>
40 #include <system_error>
41 #include <utility>
42 
43 using namespace llvm;
44 using namespace object;
45 using namespace ELF;
46 
47 namespace {
48 
49 enum ObjcopyID {
50   OBJCOPY_INVALID = 0, // This is not an option ID.
51 #define OPTION(PREFIX, NAME, ID, KIND, GROUP, ALIAS, ALIASARGS, FLAGS, PARAM,  \
52                HELPTEXT, METAVAR, VALUES)                                      \
53   OBJCOPY_##ID,
54 #include "ObjcopyOpts.inc"
55 #undef OPTION
56 };
57 
58 #define PREFIX(NAME, VALUE) const char *const OBJCOPY_##NAME[] = VALUE;
59 #include "ObjcopyOpts.inc"
60 #undef PREFIX
61 
62 static const opt::OptTable::Info ObjcopyInfoTable[] = {
63 #define OPTION(PREFIX, NAME, ID, KIND, GROUP, ALIAS, ALIASARGS, FLAGS, PARAM,  \
64                HELPTEXT, METAVAR, VALUES)                                      \
65   {OBJCOPY_##PREFIX,                                                           \
66    NAME,                                                                       \
67    HELPTEXT,                                                                   \
68    METAVAR,                                                                    \
69    OBJCOPY_##ID,                                                               \
70    opt::Option::KIND##Class,                                                   \
71    PARAM,                                                                      \
72    FLAGS,                                                                      \
73    OBJCOPY_##GROUP,                                                            \
74    OBJCOPY_##ALIAS,                                                            \
75    ALIASARGS,                                                                  \
76    VALUES},
77 #include "ObjcopyOpts.inc"
78 #undef OPTION
79 };
80 
81 class ObjcopyOptTable : public opt::OptTable {
82 public:
83   ObjcopyOptTable() : OptTable(ObjcopyInfoTable, true) {}
84 };
85 
86 enum StripID {
87   STRIP_INVALID = 0, // This is not an option ID.
88 #define OPTION(PREFIX, NAME, ID, KIND, GROUP, ALIAS, ALIASARGS, FLAGS, PARAM,  \
89                HELPTEXT, METAVAR, VALUES)                                      \
90   STRIP_##ID,
91 #include "StripOpts.inc"
92 #undef OPTION
93 };
94 
95 #define PREFIX(NAME, VALUE) const char *const STRIP_##NAME[] = VALUE;
96 #include "StripOpts.inc"
97 #undef PREFIX
98 
99 static const opt::OptTable::Info StripInfoTable[] = {
100 #define OPTION(PREFIX, NAME, ID, KIND, GROUP, ALIAS, ALIASARGS, FLAGS, PARAM,  \
101                HELPTEXT, METAVAR, VALUES)                                      \
102   {STRIP_##PREFIX, NAME,       HELPTEXT,                                       \
103    METAVAR,        STRIP_##ID, opt::Option::KIND##Class,                       \
104    PARAM,          FLAGS,      STRIP_##GROUP,                                  \
105    STRIP_##ALIAS,  ALIASARGS,  VALUES},
106 #include "StripOpts.inc"
107 #undef OPTION
108 };
109 
110 class StripOptTable : public opt::OptTable {
111 public:
112   StripOptTable() : OptTable(StripInfoTable, true) {}
113 };
114 
115 } // namespace
116 
117 // The name this program was invoked as.
118 static StringRef ToolName;
119 
120 namespace llvm {
121 
122 LLVM_ATTRIBUTE_NORETURN void error(Twine Message) {
123   errs() << ToolName << ": " << Message << ".\n";
124   errs().flush();
125   exit(1);
126 }
127 
128 LLVM_ATTRIBUTE_NORETURN void reportError(StringRef File, std::error_code EC) {
129   assert(EC);
130   errs() << ToolName << ": '" << File << "': " << EC.message() << ".\n";
131   exit(1);
132 }
133 
134 LLVM_ATTRIBUTE_NORETURN void reportError(StringRef File, Error E) {
135   assert(E);
136   std::string Buf;
137   raw_string_ostream OS(Buf);
138   logAllUnhandledErrors(std::move(E), OS, "");
139   OS.flush();
140   errs() << ToolName << ": '" << File << "': " << Buf;
141   exit(1);
142 }
143 
144 } // end namespace llvm
145 
146 struct CopyConfig {
147   StringRef OutputFilename;
148   StringRef InputFilename;
149   StringRef OutputFormat;
150   StringRef InputFormat;
151   StringRef BinaryArch;
152 
153   StringRef SplitDWO;
154   StringRef AddGnuDebugLink;
155   std::vector<StringRef> ToRemove;
156   std::vector<StringRef> Keep;
157   std::vector<StringRef> OnlyKeep;
158   std::vector<StringRef> AddSection;
159   std::vector<StringRef> SymbolsToLocalize;
160   std::vector<StringRef> SymbolsToGlobalize;
161   std::vector<StringRef> SymbolsToWeaken;
162   std::vector<StringRef> SymbolsToRemove;
163   std::vector<StringRef> SymbolsToKeep;
164   StringMap<StringRef> SymbolsToRename;
165   bool StripAll = false;
166   bool StripAllGNU = false;
167   bool StripDebug = false;
168   bool StripSections = false;
169   bool StripNonAlloc = false;
170   bool StripDWO = false;
171   bool StripUnneeded = false;
172   bool ExtractDWO = false;
173   bool LocalizeHidden = false;
174   bool Weaken = false;
175   bool DiscardAll = false;
176   bool OnlyKeepDebug = false;
177   bool KeepFileSymbols = false;
178 };
179 
180 using SectionPred = std::function<bool(const SectionBase &Sec)>;
181 
182 bool IsDWOSection(const SectionBase &Sec) { return Sec.Name.endswith(".dwo"); }
183 
184 bool OnlyKeepDWOPred(const Object &Obj, const SectionBase &Sec) {
185   // We can't remove the section header string table.
186   if (&Sec == Obj.SectionNames)
187     return false;
188   // Short of keeping the string table we want to keep everything that is a DWO
189   // section and remove everything else.
190   return !IsDWOSection(Sec);
191 }
192 
193 std::unique_ptr<Writer> CreateWriter(const CopyConfig &Config, Object &Obj,
194                                      StringRef File, ElfType OutputElfType) {
195   if (Config.OutputFormat == "binary") {
196     return llvm::make_unique<BinaryWriter>(File, Obj);
197   }
198   // Depending on the initial ELFT and OutputFormat we need a different Writer.
199   switch (OutputElfType) {
200   case ELFT_ELF32LE:
201     return llvm::make_unique<ELFWriter<ELF32LE>>(File, Obj,
202                                                  !Config.StripSections);
203   case ELFT_ELF64LE:
204     return llvm::make_unique<ELFWriter<ELF64LE>>(File, Obj,
205                                                  !Config.StripSections);
206   case ELFT_ELF32BE:
207     return llvm::make_unique<ELFWriter<ELF32BE>>(File, Obj,
208                                                  !Config.StripSections);
209   case ELFT_ELF64BE:
210     return llvm::make_unique<ELFWriter<ELF64BE>>(File, Obj,
211                                                  !Config.StripSections);
212   }
213   llvm_unreachable("Invalid output format");
214 }
215 
216 void SplitDWOToFile(const CopyConfig &Config, const Reader &Reader,
217                     StringRef File, ElfType OutputElfType) {
218   auto DWOFile = Reader.create();
219   DWOFile->removeSections(
220       [&](const SectionBase &Sec) { return OnlyKeepDWOPred(*DWOFile, Sec); });
221   auto Writer = CreateWriter(Config, *DWOFile, File, OutputElfType);
222   Writer->finalize();
223   Writer->write();
224 }
225 
226 // This function handles the high level operations of GNU objcopy including
227 // handling command line options. It's important to outline certain properties
228 // we expect to hold of the command line operations. Any operation that "keeps"
229 // should keep regardless of a remove. Additionally any removal should respect
230 // any previous removals. Lastly whether or not something is removed shouldn't
231 // depend a) on the order the options occur in or b) on some opaque priority
232 // system. The only priority is that keeps/copies overrule removes.
233 void HandleArgs(const CopyConfig &Config, Object &Obj, const Reader &Reader,
234                 ElfType OutputElfType) {
235 
236   if (!Config.SplitDWO.empty()) {
237     SplitDWOToFile(Config, Reader, Config.SplitDWO, OutputElfType);
238   }
239 
240   // TODO: update or remove symbols only if there is an option that affects
241   // them.
242   if (Obj.SymbolTable) {
243     Obj.SymbolTable->updateSymbols([&](Symbol &Sym) {
244       if ((Config.LocalizeHidden &&
245            (Sym.Visibility == STV_HIDDEN || Sym.Visibility == STV_INTERNAL)) ||
246           (!Config.SymbolsToLocalize.empty() &&
247            is_contained(Config.SymbolsToLocalize, Sym.Name)))
248         Sym.Binding = STB_LOCAL;
249 
250       if (!Config.SymbolsToGlobalize.empty() &&
251           is_contained(Config.SymbolsToGlobalize, Sym.Name))
252         Sym.Binding = STB_GLOBAL;
253 
254       if (!Config.SymbolsToWeaken.empty() &&
255           is_contained(Config.SymbolsToWeaken, Sym.Name) &&
256           Sym.Binding == STB_GLOBAL)
257         Sym.Binding = STB_WEAK;
258 
259       if (Config.Weaken && Sym.Binding == STB_GLOBAL &&
260           Sym.getShndx() != SHN_UNDEF)
261         Sym.Binding = STB_WEAK;
262 
263       const auto I = Config.SymbolsToRename.find(Sym.Name);
264       if (I != Config.SymbolsToRename.end())
265         Sym.Name = I->getValue();
266     });
267 
268     // The purpose of this loop is to mark symbols referenced by sections
269     // (like GroupSection or RelocationSection). This way, we know which
270     // symbols are still 'needed' and wich are not.
271     if (Config.StripUnneeded) {
272       for (auto &Section : Obj.sections())
273         Section.markSymbols();
274     }
275 
276     Obj.removeSymbols([&](const Symbol &Sym) {
277       if ((!Config.SymbolsToKeep.empty() &&
278            is_contained(Config.SymbolsToKeep, Sym.Name)) ||
279           (Config.KeepFileSymbols && Sym.Type == STT_FILE))
280         return false;
281 
282       if (Config.DiscardAll && Sym.Binding == STB_LOCAL &&
283           Sym.getShndx() != SHN_UNDEF && Sym.Type != STT_FILE &&
284           Sym.Type != STT_SECTION)
285         return true;
286 
287       if (Config.StripAll || Config.StripAllGNU)
288         return true;
289 
290       if (!Config.SymbolsToRemove.empty() &&
291           is_contained(Config.SymbolsToRemove, Sym.Name)) {
292         return true;
293       }
294 
295       if (Config.StripUnneeded && !Sym.Referenced &&
296           (Sym.Binding == STB_LOCAL || Sym.getShndx() == SHN_UNDEF) &&
297           Sym.Type != STT_FILE && Sym.Type != STT_SECTION)
298         return true;
299 
300       return false;
301     });
302   }
303 
304   SectionPred RemovePred = [](const SectionBase &) { return false; };
305 
306   // Removes:
307   if (!Config.ToRemove.empty()) {
308     RemovePred = [&Config](const SectionBase &Sec) {
309       return std::find(std::begin(Config.ToRemove), std::end(Config.ToRemove),
310                        Sec.Name) != std::end(Config.ToRemove);
311     };
312   }
313 
314   if (Config.StripDWO || !Config.SplitDWO.empty())
315     RemovePred = [RemovePred](const SectionBase &Sec) {
316       return IsDWOSection(Sec) || RemovePred(Sec);
317     };
318 
319   if (Config.ExtractDWO)
320     RemovePred = [RemovePred, &Obj](const SectionBase &Sec) {
321       return OnlyKeepDWOPred(Obj, Sec) || RemovePred(Sec);
322     };
323 
324   if (Config.StripAllGNU)
325     RemovePred = [RemovePred, &Obj](const SectionBase &Sec) {
326       if (RemovePred(Sec))
327         return true;
328       if ((Sec.Flags & SHF_ALLOC) != 0)
329         return false;
330       if (&Sec == Obj.SectionNames)
331         return false;
332       switch (Sec.Type) {
333       case SHT_SYMTAB:
334       case SHT_REL:
335       case SHT_RELA:
336       case SHT_STRTAB:
337         return true;
338       }
339       return Sec.Name.startswith(".debug");
340     };
341 
342   if (Config.StripSections) {
343     RemovePred = [RemovePred](const SectionBase &Sec) {
344       return RemovePred(Sec) || (Sec.Flags & SHF_ALLOC) == 0;
345     };
346   }
347 
348   if (Config.StripDebug) {
349     RemovePred = [RemovePred](const SectionBase &Sec) {
350       return RemovePred(Sec) || Sec.Name.startswith(".debug");
351     };
352   }
353 
354   if (Config.StripNonAlloc)
355     RemovePred = [RemovePred, &Obj](const SectionBase &Sec) {
356       if (RemovePred(Sec))
357         return true;
358       if (&Sec == Obj.SectionNames)
359         return false;
360       return (Sec.Flags & SHF_ALLOC) == 0;
361     };
362 
363   if (Config.StripAll)
364     RemovePred = [RemovePred, &Obj](const SectionBase &Sec) {
365       if (RemovePred(Sec))
366         return true;
367       if (&Sec == Obj.SectionNames)
368         return false;
369       if (Sec.Name.startswith(".gnu.warning"))
370         return false;
371       return (Sec.Flags & SHF_ALLOC) == 0;
372     };
373 
374   // Explicit copies:
375   if (!Config.OnlyKeep.empty()) {
376     RemovePred = [&Config, RemovePred, &Obj](const SectionBase &Sec) {
377       // Explicitly keep these sections regardless of previous removes.
378       if (std::find(std::begin(Config.OnlyKeep), std::end(Config.OnlyKeep),
379                     Sec.Name) != std::end(Config.OnlyKeep))
380         return false;
381 
382       // Allow all implicit removes.
383       if (RemovePred(Sec))
384         return true;
385 
386       // Keep special sections.
387       if (Obj.SectionNames == &Sec)
388         return false;
389       if (Obj.SymbolTable == &Sec || Obj.SymbolTable->getStrTab() == &Sec)
390         return false;
391 
392       // Remove everything else.
393       return true;
394     };
395   }
396 
397   if (!Config.Keep.empty()) {
398     RemovePred = [Config, RemovePred](const SectionBase &Sec) {
399       // Explicitly keep these sections regardless of previous removes.
400       if (std::find(std::begin(Config.Keep), std::end(Config.Keep), Sec.Name) !=
401           std::end(Config.Keep))
402         return false;
403       // Otherwise defer to RemovePred.
404       return RemovePred(Sec);
405     };
406   }
407 
408   // This has to be the last predicate assignment.
409   // If the option --keep-symbol has been specified
410   // and at least one of those symbols is present
411   // (equivalently, the updated symbol table is not empty)
412   // the symbol table and the string table should not be removed.
413   if ((!Config.SymbolsToKeep.empty() || Config.KeepFileSymbols) &&
414       !Obj.SymbolTable->empty()) {
415     RemovePred = [&Obj, RemovePred](const SectionBase &Sec) {
416       if (&Sec == Obj.SymbolTable || &Sec == Obj.SymbolTable->getStrTab())
417         return false;
418       return RemovePred(Sec);
419     };
420   }
421 
422   Obj.removeSections(RemovePred);
423 
424   if (!Config.AddSection.empty()) {
425     for (const auto &Flag : Config.AddSection) {
426       auto SecPair = Flag.split("=");
427       auto SecName = SecPair.first;
428       auto File = SecPair.second;
429       auto BufOrErr = MemoryBuffer::getFile(File);
430       if (!BufOrErr)
431         reportError(File, BufOrErr.getError());
432       auto Buf = std::move(*BufOrErr);
433       auto BufPtr = reinterpret_cast<const uint8_t *>(Buf->getBufferStart());
434       auto BufSize = Buf->getBufferSize();
435       Obj.addSection<OwnedDataSection>(SecName,
436                                        ArrayRef<uint8_t>(BufPtr, BufSize));
437     }
438   }
439 
440   if (!Config.AddGnuDebugLink.empty())
441     Obj.addSection<GnuDebugLinkSection>(Config.AddGnuDebugLink);
442 }
443 
444 std::unique_ptr<Reader> CreateReader(StringRef InputFilename,
445                                      ElfType &OutputElfType) {
446   // Right now we can only read ELF files so there's only one reader;
447   auto Out = llvm::make_unique<ELFReader>(InputFilename);
448   // We need to set the default ElfType for output.
449   OutputElfType = Out->getElfType();
450   return std::move(Out);
451 }
452 
453 void ExecuteElfObjcopy(const CopyConfig &Config) {
454   ElfType OutputElfType;
455   auto Reader = CreateReader(Config.InputFilename, OutputElfType);
456   auto Obj = Reader->create();
457   auto Writer =
458       CreateWriter(Config, *Obj, Config.OutputFilename, OutputElfType);
459   HandleArgs(Config, *Obj, *Reader, OutputElfType);
460   Writer->finalize();
461   Writer->write();
462 }
463 
464 // ParseObjcopyOptions returns the config and sets the input arguments. If a
465 // help flag is set then ParseObjcopyOptions will print the help messege and
466 // exit.
467 CopyConfig ParseObjcopyOptions(ArrayRef<const char *> ArgsArr) {
468   ObjcopyOptTable T;
469   unsigned MissingArgumentIndex, MissingArgumentCount;
470   llvm::opt::InputArgList InputArgs =
471       T.ParseArgs(ArgsArr, MissingArgumentIndex, MissingArgumentCount);
472 
473   if (InputArgs.size() == 0) {
474     T.PrintHelp(errs(), "llvm-objcopy <input> [ <output> ]", "objcopy tool");
475     exit(1);
476   }
477 
478   if (InputArgs.hasArg(OBJCOPY_help)) {
479     T.PrintHelp(outs(), "llvm-objcopy <input> [ <output> ]", "objcopy tool");
480     exit(0);
481   }
482 
483   SmallVector<const char *, 2> Positional;
484 
485   for (auto Arg : InputArgs.filtered(OBJCOPY_UNKNOWN))
486     error("unknown argument '" + Arg->getAsString(InputArgs) + "'");
487 
488   for (auto Arg : InputArgs.filtered(OBJCOPY_INPUT))
489     Positional.push_back(Arg->getValue());
490 
491   if (Positional.empty())
492     error("No input file specified");
493 
494   if (Positional.size() > 2)
495     error("Too many positional arguments");
496 
497   CopyConfig Config;
498   Config.InputFilename = Positional[0];
499   Config.OutputFilename = Positional[Positional.size() == 1 ? 0 : 1];
500   Config.InputFormat = InputArgs.getLastArgValue(OBJCOPY_input_target);
501   Config.OutputFormat = InputArgs.getLastArgValue(OBJCOPY_output_target);
502   Config.BinaryArch = InputArgs.getLastArgValue(OBJCOPY_binary_architecture);
503 
504   Config.SplitDWO = InputArgs.getLastArgValue(OBJCOPY_split_dwo);
505   Config.AddGnuDebugLink = InputArgs.getLastArgValue(OBJCOPY_add_gnu_debuglink);
506 
507   for (auto Arg : InputArgs.filtered(OBJCOPY_redefine_symbol)) {
508     if (!StringRef(Arg->getValue()).contains('='))
509       error("Bad format for --redefine-sym");
510     auto Old2New = StringRef(Arg->getValue()).split('=');
511     if (!Config.SymbolsToRename.insert(Old2New).second)
512       error("Multiple redefinition of symbol " + Old2New.first);
513   }
514 
515   for (auto Arg : InputArgs.filtered(OBJCOPY_remove_section))
516     Config.ToRemove.push_back(Arg->getValue());
517   for (auto Arg : InputArgs.filtered(OBJCOPY_keep))
518     Config.Keep.push_back(Arg->getValue());
519   for (auto Arg : InputArgs.filtered(OBJCOPY_only_keep))
520     Config.OnlyKeep.push_back(Arg->getValue());
521   for (auto Arg : InputArgs.filtered(OBJCOPY_add_section))
522     Config.AddSection.push_back(Arg->getValue());
523   Config.StripAll = InputArgs.hasArg(OBJCOPY_strip_all);
524   Config.StripAllGNU = InputArgs.hasArg(OBJCOPY_strip_all_gnu);
525   Config.StripDebug = InputArgs.hasArg(OBJCOPY_strip_debug);
526   Config.StripDWO = InputArgs.hasArg(OBJCOPY_strip_dwo);
527   Config.StripSections = InputArgs.hasArg(OBJCOPY_strip_sections);
528   Config.StripNonAlloc = InputArgs.hasArg(OBJCOPY_strip_non_alloc);
529   Config.StripUnneeded = InputArgs.hasArg(OBJCOPY_strip_unneeded);
530   Config.ExtractDWO = InputArgs.hasArg(OBJCOPY_extract_dwo);
531   Config.LocalizeHidden = InputArgs.hasArg(OBJCOPY_localize_hidden);
532   Config.Weaken = InputArgs.hasArg(OBJCOPY_weaken);
533   Config.DiscardAll = InputArgs.hasArg(OBJCOPY_discard_all);
534   Config.OnlyKeepDebug = InputArgs.hasArg(OBJCOPY_only_keep_debug);
535   Config.KeepFileSymbols = InputArgs.hasArg(OBJCOPY_keep_file_symbols);
536   for (auto Arg : InputArgs.filtered(OBJCOPY_localize_symbol))
537     Config.SymbolsToLocalize.push_back(Arg->getValue());
538   for (auto Arg : InputArgs.filtered(OBJCOPY_globalize_symbol))
539     Config.SymbolsToGlobalize.push_back(Arg->getValue());
540   for (auto Arg : InputArgs.filtered(OBJCOPY_weaken_symbol))
541     Config.SymbolsToWeaken.push_back(Arg->getValue());
542   for (auto Arg : InputArgs.filtered(OBJCOPY_strip_symbol))
543     Config.SymbolsToRemove.push_back(Arg->getValue());
544   for (auto Arg : InputArgs.filtered(OBJCOPY_keep_symbol))
545     Config.SymbolsToKeep.push_back(Arg->getValue());
546 
547   return Config;
548 }
549 
550 // ParseStripOptions returns the config and sets the input arguments. If a
551 // help flag is set then ParseStripOptions will print the help messege and
552 // exit.
553 CopyConfig ParseStripOptions(ArrayRef<const char *> ArgsArr) {
554   StripOptTable T;
555   unsigned MissingArgumentIndex, MissingArgumentCount;
556   llvm::opt::InputArgList InputArgs =
557       T.ParseArgs(ArgsArr, MissingArgumentIndex, MissingArgumentCount);
558 
559   if (InputArgs.size() == 0) {
560     T.PrintHelp(errs(), "llvm-strip <input> [ <output> ]", "strip tool");
561     exit(1);
562   }
563 
564   if (InputArgs.hasArg(STRIP_help)) {
565     T.PrintHelp(outs(), "llvm-strip <input> [ <output> ]", "strip tool");
566     exit(0);
567   }
568 
569   SmallVector<const char *, 2> Positional;
570   for (auto Arg : InputArgs.filtered(STRIP_UNKNOWN))
571     error("unknown argument '" + Arg->getAsString(InputArgs) + "'");
572   for (auto Arg : InputArgs.filtered(STRIP_INPUT))
573     Positional.push_back(Arg->getValue());
574 
575   if (Positional.empty())
576     error("No input file specified");
577 
578   if (Positional.size() > 2)
579     error("Support for multiple input files is not implemented yet");
580 
581   CopyConfig Config;
582   Config.InputFilename = Positional[0];
583   Config.OutputFilename =
584       InputArgs.getLastArgValue(STRIP_output, Positional[0]);
585 
586   // Strip debug info only.
587   Config.StripDebug = InputArgs.hasArg(STRIP_strip_debug);
588 
589   Config.DiscardAll = InputArgs.hasArg(STRIP_discard_all);
590 
591   if (!Config.StripDebug && !Config.DiscardAll)
592     Config.StripAll = true;
593 
594   for (auto Arg : InputArgs.filtered(STRIP_remove_section))
595     Config.ToRemove.push_back(Arg->getValue());
596 
597   for (auto Arg : InputArgs.filtered(STRIP_keep_symbol))
598     Config.SymbolsToKeep.push_back(Arg->getValue());
599 
600   return Config;
601 }
602 
603 int main(int argc, char **argv) {
604   InitLLVM X(argc, argv);
605   ToolName = argv[0];
606   CopyConfig Config;
607   if (sys::path::stem(ToolName).endswith_lower("strip"))
608     Config = ParseStripOptions(makeArrayRef(argv + 1, argc));
609   else
610     Config = ParseObjcopyOptions(makeArrayRef(argv + 1, argc));
611   ExecuteElfObjcopy(Config);
612 }
613