1 //===- llvm-readobj.cpp - Dump contents of an Object File -----------------===//
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 is a tool similar to readelf, except it works on multiple object file
11 // formats. The main purpose of this tool is to provide detailed output suitable
12 // for FileCheck.
13 //
14 // Flags should be similar to readelf where supported, but the output format
15 // does not need to be identical. The point is to not make users learn yet
16 // another set of flags.
17 //
18 // Output should be specialized for each format where appropriate.
19 //
20 //===----------------------------------------------------------------------===//
21 
22 #include "llvm-readobj.h"
23 #include "Error.h"
24 #include "ObjDumper.h"
25 #include "StreamWriter.h"
26 #include "llvm/Object/Archive.h"
27 #include "llvm/Object/ELFObjectFile.h"
28 #include "llvm/Object/ObjectFile.h"
29 #include "llvm/Support/Casting.h"
30 #include "llvm/Support/CommandLine.h"
31 #include "llvm/Support/DataTypes.h"
32 #include "llvm/Support/Debug.h"
33 #include "llvm/Support/FileSystem.h"
34 #include "llvm/Support/ManagedStatic.h"
35 #include "llvm/Support/PrettyStackTrace.h"
36 #include "llvm/Support/Signals.h"
37 #include "llvm/Support/TargetRegistry.h"
38 #include "llvm/Support/TargetSelect.h"
39 #include <string>
40 #include <system_error>
41 
42 
43 using namespace llvm;
44 using namespace llvm::object;
45 
46 namespace opts {
47   cl::list<std::string> InputFilenames(cl::Positional,
48     cl::desc("<input object files>"),
49     cl::ZeroOrMore);
50 
51   // -file-headers, -h
52   cl::opt<bool> FileHeaders("file-headers",
53     cl::desc("Display file headers "));
54   cl::alias FileHeadersShort("h",
55     cl::desc("Alias for --file-headers"),
56     cl::aliasopt(FileHeaders));
57 
58   // -sections, -s
59   cl::opt<bool> Sections("sections",
60     cl::desc("Display all sections."));
61   cl::alias SectionsShort("s",
62     cl::desc("Alias for --sections"),
63     cl::aliasopt(Sections));
64 
65   // -section-relocations, -sr
66   cl::opt<bool> SectionRelocations("section-relocations",
67     cl::desc("Display relocations for each section shown."));
68   cl::alias SectionRelocationsShort("sr",
69     cl::desc("Alias for --section-relocations"),
70     cl::aliasopt(SectionRelocations));
71 
72   // -section-symbols, -st
73   cl::opt<bool> SectionSymbols("section-symbols",
74     cl::desc("Display symbols for each section shown."));
75   cl::alias SectionSymbolsShort("st",
76     cl::desc("Alias for --section-symbols"),
77     cl::aliasopt(SectionSymbols));
78 
79   // -section-data, -sd
80   cl::opt<bool> SectionData("section-data",
81     cl::desc("Display section data for each section shown."));
82   cl::alias SectionDataShort("sd",
83     cl::desc("Alias for --section-data"),
84     cl::aliasopt(SectionData));
85 
86   // -relocations, -r
87   cl::opt<bool> Relocations("relocations",
88     cl::desc("Display the relocation entries in the file"));
89   cl::alias RelocationsShort("r",
90     cl::desc("Alias for --relocations"),
91     cl::aliasopt(Relocations));
92 
93   // -symbols, -t
94   cl::opt<bool> Symbols("symbols",
95     cl::desc("Display the symbol table"));
96   cl::alias SymbolsShort("t",
97     cl::desc("Alias for --symbols"),
98     cl::aliasopt(Symbols));
99 
100   // -dyn-symbols, -dt
101   cl::opt<bool> DynamicSymbols("dyn-symbols",
102     cl::desc("Display the dynamic symbol table"));
103   cl::alias DynamicSymbolsShort("dt",
104     cl::desc("Alias for --dyn-symbols"),
105     cl::aliasopt(DynamicSymbols));
106 
107   // -unwind, -u
108   cl::opt<bool> UnwindInfo("unwind",
109     cl::desc("Display unwind information"));
110   cl::alias UnwindInfoShort("u",
111     cl::desc("Alias for --unwind"),
112     cl::aliasopt(UnwindInfo));
113 
114   // -dynamic-table
115   cl::opt<bool> DynamicTable("dynamic-table",
116     cl::desc("Display the ELF .dynamic section table"));
117 
118   // -needed-libs
119   cl::opt<bool> NeededLibraries("needed-libs",
120     cl::desc("Display the needed libraries"));
121 
122   // -program-headers
123   cl::opt<bool> ProgramHeaders("program-headers",
124     cl::desc("Display ELF program headers"));
125 
126   // -expand-relocs
127   cl::opt<bool> ExpandRelocs("expand-relocs",
128     cl::desc("Expand each shown relocation to multiple lines"));
129 
130   // -codeview-linetables
131   cl::opt<bool> CodeViewLineTables("codeview-linetables",
132     cl::desc("Display CodeView line table information"));
133 
134   // -arm-attributes, -a
135   cl::opt<bool> ARMAttributes("arm-attributes",
136                               cl::desc("Display the ARM attributes section"));
137   cl::alias ARMAttributesShort("-a", cl::desc("Alias for --arm-attributes"),
138                                cl::aliasopt(ARMAttributes));
139 
140   // -mips-plt-got
141   cl::opt<bool>
142   MipsPLTGOT("mips-plt-got",
143              cl::desc("Display the MIPS GOT and PLT GOT sections"));
144 } // namespace opts
145 
146 static int ReturnValue = EXIT_SUCCESS;
147 
148 namespace llvm {
149 
150 bool error(std::error_code EC) {
151   if (!EC)
152     return false;
153 
154   ReturnValue = EXIT_FAILURE;
155   outs() << "\nError reading file: " << EC.message() << ".\n";
156   outs().flush();
157   return true;
158 }
159 
160 bool relocAddressLess(RelocationRef a, RelocationRef b) {
161   uint64_t a_addr, b_addr;
162   if (error(a.getOffset(a_addr))) return false;
163   if (error(b.getOffset(b_addr))) return false;
164   return a_addr < b_addr;
165 }
166 
167 } // namespace llvm
168 
169 static void reportError(StringRef Input, std::error_code EC) {
170   if (Input == "-")
171     Input = "<stdin>";
172 
173   errs() << Input << ": " << EC.message() << "\n";
174   errs().flush();
175   ReturnValue = EXIT_FAILURE;
176 }
177 
178 static void reportError(StringRef Input, StringRef Message) {
179   if (Input == "-")
180     Input = "<stdin>";
181 
182   errs() << Input << ": " << Message << "\n";
183   ReturnValue = EXIT_FAILURE;
184 }
185 
186 static bool isMipsArch(unsigned Arch) {
187   switch (Arch) {
188   case llvm::Triple::mips:
189   case llvm::Triple::mipsel:
190   case llvm::Triple::mips64:
191   case llvm::Triple::mips64el:
192     return true;
193   default:
194     return false;
195   }
196 }
197 
198 /// @brief Creates an format-specific object file dumper.
199 static std::error_code createDumper(const ObjectFile *Obj, StreamWriter &Writer,
200                                     std::unique_ptr<ObjDumper> &Result) {
201   if (!Obj)
202     return readobj_error::unsupported_file_format;
203 
204   if (Obj->isCOFF())
205     return createCOFFDumper(Obj, Writer, Result);
206   if (Obj->isELF())
207     return createELFDumper(Obj, Writer, Result);
208   if (Obj->isMachO())
209     return createMachODumper(Obj, Writer, Result);
210 
211   return readobj_error::unsupported_obj_file_format;
212 }
213 
214 static StringRef getLoadName(const ObjectFile *Obj) {
215   if (auto *ELF = dyn_cast<ELF32LEObjectFile>(Obj))
216     return ELF->getLoadName();
217   if (auto *ELF = dyn_cast<ELF64LEObjectFile>(Obj))
218     return ELF->getLoadName();
219   if (auto *ELF = dyn_cast<ELF32BEObjectFile>(Obj))
220     return ELF->getLoadName();
221   if (auto *ELF = dyn_cast<ELF64BEObjectFile>(Obj))
222     return ELF->getLoadName();
223   llvm_unreachable("Not ELF");
224 }
225 
226 /// @brief Dumps the specified object file.
227 static void dumpObject(const ObjectFile *Obj) {
228   StreamWriter Writer(outs());
229   std::unique_ptr<ObjDumper> Dumper;
230   if (std::error_code EC = createDumper(Obj, Writer, Dumper)) {
231     reportError(Obj->getFileName(), EC);
232     return;
233   }
234 
235   outs() << '\n';
236   outs() << "File: " << Obj->getFileName() << "\n";
237   outs() << "Format: " << Obj->getFileFormatName() << "\n";
238   outs() << "Arch: "
239          << Triple::getArchTypeName((llvm::Triple::ArchType)Obj->getArch())
240          << "\n";
241   outs() << "AddressSize: " << (8*Obj->getBytesInAddress()) << "bit\n";
242   if (Obj->isELF())
243     outs() << "LoadName: " << getLoadName(Obj) << "\n";
244 
245   if (opts::FileHeaders)
246     Dumper->printFileHeaders();
247   if (opts::Sections)
248     Dumper->printSections();
249   if (opts::Relocations)
250     Dumper->printRelocations();
251   if (opts::Symbols)
252     Dumper->printSymbols();
253   if (opts::DynamicSymbols)
254     Dumper->printDynamicSymbols();
255   if (opts::UnwindInfo)
256     Dumper->printUnwindInfo();
257   if (opts::DynamicTable)
258     Dumper->printDynamicTable();
259   if (opts::NeededLibraries)
260     Dumper->printNeededLibraries();
261   if (opts::ProgramHeaders)
262     Dumper->printProgramHeaders();
263   if (Obj->getArch() == llvm::Triple::arm && Obj->isELF())
264     if (opts::ARMAttributes)
265       Dumper->printAttributes();
266   if (isMipsArch(Obj->getArch()) && Obj->isELF())
267     if (opts::MipsPLTGOT)
268       Dumper->printMipsPLTGOT();
269 }
270 
271 
272 /// @brief Dumps each object file in \a Arc;
273 static void dumpArchive(const Archive *Arc) {
274   for (Archive::child_iterator ArcI = Arc->child_begin(),
275                                ArcE = Arc->child_end();
276                                ArcI != ArcE; ++ArcI) {
277     ErrorOr<std::unique_ptr<Binary>> ChildOrErr = ArcI->getAsBinary();
278     if (std::error_code EC = ChildOrErr.getError()) {
279       // Ignore non-object files.
280       if (EC != object_error::invalid_file_type)
281         reportError(Arc->getFileName(), EC.message());
282       continue;
283     }
284 
285     if (ObjectFile *Obj = dyn_cast<ObjectFile>(&*ChildOrErr.get()))
286       dumpObject(Obj);
287     else
288       reportError(Arc->getFileName(), readobj_error::unrecognized_file_format);
289   }
290 }
291 
292 
293 /// @brief Opens \a File and dumps it.
294 static void dumpInput(StringRef File) {
295   // If file isn't stdin, check that it exists.
296   if (File != "-" && !sys::fs::exists(File)) {
297     reportError(File, readobj_error::file_not_found);
298     return;
299   }
300 
301   // Attempt to open the binary.
302   ErrorOr<std::unique_ptr<Binary>> BinaryOrErr = createBinary(File);
303   if (std::error_code EC = BinaryOrErr.getError()) {
304     reportError(File, EC);
305     return;
306   }
307   Binary &Binary = *BinaryOrErr.get();
308 
309   if (Archive *Arc = dyn_cast<Archive>(&Binary))
310     dumpArchive(Arc);
311   else if (ObjectFile *Obj = dyn_cast<ObjectFile>(&Binary))
312     dumpObject(Obj);
313   else
314     reportError(File, readobj_error::unrecognized_file_format);
315 }
316 
317 
318 int main(int argc, const char *argv[]) {
319   sys::PrintStackTraceOnErrorSignal();
320   PrettyStackTraceProgram X(argc, argv);
321   llvm_shutdown_obj Y;
322 
323   // Initialize targets.
324   llvm::InitializeAllTargetInfos();
325 
326   // Register the target printer for --version.
327   cl::AddExtraVersionPrinter(TargetRegistry::printRegisteredTargetsForVersion);
328 
329   cl::ParseCommandLineOptions(argc, argv, "LLVM Object Reader\n");
330 
331   // Default to stdin if no filename is specified.
332   if (opts::InputFilenames.size() == 0)
333     opts::InputFilenames.push_back("-");
334 
335   std::for_each(opts::InputFilenames.begin(), opts::InputFilenames.end(),
336                 dumpInput);
337 
338   return ReturnValue;
339 }
340