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      1 //===-- llvm-nm.cpp - Symbol table 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 program is a utility that works like traditional Unix "nm",
     11 // that is, it prints out the names of symbols in a bitcode file,
     12 // along with some information about each symbol.
     13 //
     14 // This "nm" does not print symbols' addresses. It supports many of
     15 // the features of GNU "nm", including its different output formats.
     16 //
     17 //===----------------------------------------------------------------------===//
     18 
     19 #include "llvm/LLVMContext.h"
     20 #include "llvm/Module.h"
     21 #include "llvm/Bitcode/ReaderWriter.h"
     22 #include "llvm/Bitcode/Archive.h"
     23 #include "llvm/Object/Archive.h"
     24 #include "llvm/Object/ObjectFile.h"
     25 #include "llvm/Support/CommandLine.h"
     26 #include "llvm/Support/FileSystem.h"
     27 #include "llvm/Support/ManagedStatic.h"
     28 #include "llvm/Support/MemoryBuffer.h"
     29 #include "llvm/Support/PrettyStackTrace.h"
     30 #include "llvm/Support/Program.h"
     31 #include "llvm/Support/raw_ostream.h"
     32 #include "llvm/Support/Signals.h"
     33 #include "llvm/Support/Format.h"
     34 #include "llvm/Support/system_error.h"
     35 #include <algorithm>
     36 #include <cctype>
     37 #include <cerrno>
     38 #include <cstring>
     39 #include <vector>
     40 using namespace llvm;
     41 using namespace object;
     42 
     43 namespace {
     44   enum OutputFormatTy { bsd, sysv, posix };
     45   cl::opt<OutputFormatTy>
     46   OutputFormat("format",
     47        cl::desc("Specify output format"),
     48          cl::values(clEnumVal(bsd,   "BSD format"),
     49                     clEnumVal(sysv,  "System V format"),
     50                     clEnumVal(posix, "POSIX.2 format"),
     51                     clEnumValEnd), cl::init(bsd));
     52   cl::alias OutputFormat2("f", cl::desc("Alias for --format"),
     53                           cl::aliasopt(OutputFormat));
     54 
     55   cl::list<std::string>
     56   InputFilenames(cl::Positional, cl::desc("<input bitcode files>"),
     57                  cl::ZeroOrMore);
     58 
     59   cl::opt<bool> UndefinedOnly("undefined-only",
     60                               cl::desc("Show only undefined symbols"));
     61   cl::alias UndefinedOnly2("u", cl::desc("Alias for --undefined-only"),
     62                            cl::aliasopt(UndefinedOnly));
     63 
     64   cl::opt<bool> DynamicSyms("dynamic",
     65                              cl::desc("Display the dynamic symbols instead "
     66                                       "of normal symbols."));
     67   cl::alias DynamicSyms2("D", cl::desc("Alias for --dynamic"),
     68                          cl::aliasopt(DynamicSyms));
     69 
     70   cl::opt<bool> DefinedOnly("defined-only",
     71                             cl::desc("Show only defined symbols"));
     72 
     73   cl::opt<bool> ExternalOnly("extern-only",
     74                              cl::desc("Show only external symbols"));
     75   cl::alias ExternalOnly2("g", cl::desc("Alias for --extern-only"),
     76                           cl::aliasopt(ExternalOnly));
     77 
     78   cl::opt<bool> BSDFormat("B", cl::desc("Alias for --format=bsd"));
     79   cl::opt<bool> POSIXFormat("P", cl::desc("Alias for --format=posix"));
     80 
     81   cl::opt<bool> PrintFileName("print-file-name",
     82     cl::desc("Precede each symbol with the object file it came from"));
     83 
     84   cl::alias PrintFileNameA("A", cl::desc("Alias for --print-file-name"),
     85                                 cl::aliasopt(PrintFileName));
     86   cl::alias PrintFileNameo("o", cl::desc("Alias for --print-file-name"),
     87                                 cl::aliasopt(PrintFileName));
     88 
     89   cl::opt<bool> DebugSyms("debug-syms",
     90     cl::desc("Show all symbols, even debugger only"));
     91   cl::alias DebugSymsa("a", cl::desc("Alias for --debug-syms"),
     92                             cl::aliasopt(DebugSyms));
     93 
     94   cl::opt<bool> NumericSort("numeric-sort",
     95     cl::desc("Sort symbols by address"));
     96   cl::alias NumericSortn("n", cl::desc("Alias for --numeric-sort"),
     97                               cl::aliasopt(NumericSort));
     98   cl::alias NumericSortv("v", cl::desc("Alias for --numeric-sort"),
     99                               cl::aliasopt(NumericSort));
    100 
    101   cl::opt<bool> NoSort("no-sort",
    102     cl::desc("Show symbols in order encountered"));
    103   cl::alias NoSortp("p", cl::desc("Alias for --no-sort"),
    104                          cl::aliasopt(NoSort));
    105 
    106   cl::opt<bool> PrintSize("print-size",
    107     cl::desc("Show symbol size instead of address"));
    108   cl::alias PrintSizeS("S", cl::desc("Alias for --print-size"),
    109                             cl::aliasopt(PrintSize));
    110 
    111   cl::opt<bool> SizeSort("size-sort", cl::desc("Sort symbols by size"));
    112 
    113   bool PrintAddress = true;
    114 
    115   bool MultipleFiles = false;
    116 
    117   std::string ToolName;
    118 }
    119 
    120 
    121 static void error(Twine message, Twine path = Twine()) {
    122   errs() << ToolName << ": " << path << ": " << message << ".\n";
    123 }
    124 
    125 static bool error(error_code ec, Twine path = Twine()) {
    126   if (ec) {
    127     error(ec.message(), path);
    128     return true;
    129   }
    130   return false;
    131 }
    132 
    133 namespace {
    134   struct NMSymbol {
    135     uint64_t  Address;
    136     uint64_t  Size;
    137     char      TypeChar;
    138     StringRef Name;
    139   };
    140 
    141   static bool CompareSymbolAddress(const NMSymbol &a, const NMSymbol &b) {
    142     if (a.Address < b.Address)
    143       return true;
    144     else if (a.Address == b.Address && a.Name < b.Name)
    145       return true;
    146     else
    147       return false;
    148 
    149   }
    150 
    151   static bool CompareSymbolSize(const NMSymbol &a, const NMSymbol &b) {
    152     if (a.Size < b.Size)
    153       return true;
    154     else if (a.Size == b.Size && a.Name < b.Name)
    155       return true;
    156     else
    157       return false;
    158   }
    159 
    160   static bool CompareSymbolName(const NMSymbol &a, const NMSymbol &b) {
    161     return a.Name < b.Name;
    162   }
    163 
    164   StringRef CurrentFilename;
    165   typedef std::vector<NMSymbol> SymbolListT;
    166   SymbolListT SymbolList;
    167 }
    168 
    169 static void SortAndPrintSymbolList() {
    170   if (!NoSort) {
    171     if (NumericSort)
    172       std::sort(SymbolList.begin(), SymbolList.end(), CompareSymbolAddress);
    173     else if (SizeSort)
    174       std::sort(SymbolList.begin(), SymbolList.end(), CompareSymbolSize);
    175     else
    176       std::sort(SymbolList.begin(), SymbolList.end(), CompareSymbolName);
    177   }
    178 
    179   if (OutputFormat == posix && MultipleFiles) {
    180     outs() << '\n' << CurrentFilename << ":\n";
    181   } else if (OutputFormat == bsd && MultipleFiles) {
    182     outs() << "\n" << CurrentFilename << ":\n";
    183   } else if (OutputFormat == sysv) {
    184     outs() << "\n\nSymbols from " << CurrentFilename << ":\n\n"
    185            << "Name                  Value   Class        Type"
    186            << "         Size   Line  Section\n";
    187   }
    188 
    189   for (SymbolListT::iterator i = SymbolList.begin(),
    190                              e = SymbolList.end(); i != e; ++i) {
    191     if ((i->TypeChar != 'U') && UndefinedOnly)
    192       continue;
    193     if ((i->TypeChar == 'U') && DefinedOnly)
    194       continue;
    195     if (SizeSort && !PrintAddress && i->Size == UnknownAddressOrSize)
    196       continue;
    197 
    198     char SymbolAddrStr[10] = "";
    199     char SymbolSizeStr[10] = "";
    200 
    201     if (OutputFormat == sysv || i->Address == object::UnknownAddressOrSize)
    202       strcpy(SymbolAddrStr, "        ");
    203     if (OutputFormat == sysv)
    204       strcpy(SymbolSizeStr, "        ");
    205 
    206     if (i->Address != object::UnknownAddressOrSize)
    207       format("%08" PRIx64, i->Address).print(SymbolAddrStr,
    208                                              sizeof(SymbolAddrStr));
    209     if (i->Size != object::UnknownAddressOrSize)
    210       format("%08" PRIx64, i->Size).print(SymbolSizeStr, sizeof(SymbolSizeStr));
    211 
    212     if (OutputFormat == posix) {
    213       outs() << i->Name << " " << i->TypeChar << " "
    214              << SymbolAddrStr << SymbolSizeStr << "\n";
    215     } else if (OutputFormat == bsd) {
    216       if (PrintAddress)
    217         outs() << SymbolAddrStr << ' ';
    218       if (PrintSize) {
    219         outs() << SymbolSizeStr;
    220         if (i->Size != object::UnknownAddressOrSize)
    221           outs() << ' ';
    222       }
    223       outs() << i->TypeChar << " " << i->Name  << "\n";
    224     } else if (OutputFormat == sysv) {
    225       std::string PaddedName (i->Name);
    226       while (PaddedName.length () < 20)
    227         PaddedName += " ";
    228       outs() << PaddedName << "|" << SymbolAddrStr << "|   "
    229              << i->TypeChar
    230              << "  |                  |" << SymbolSizeStr << "|     |\n";
    231     }
    232   }
    233 
    234   SymbolList.clear();
    235 }
    236 
    237 static char TypeCharForSymbol(GlobalValue &GV) {
    238   if (GV.isDeclaration())                                  return 'U';
    239   if (GV.hasLinkOnceLinkage())                             return 'C';
    240   if (GV.hasCommonLinkage())                               return 'C';
    241   if (GV.hasWeakLinkage())                                 return 'W';
    242   if (isa<Function>(GV) && GV.hasInternalLinkage())        return 't';
    243   if (isa<Function>(GV))                                   return 'T';
    244   if (isa<GlobalVariable>(GV) && GV.hasInternalLinkage())  return 'd';
    245   if (isa<GlobalVariable>(GV))                             return 'D';
    246   if (const GlobalAlias *GA = dyn_cast<GlobalAlias>(&GV)) {
    247     const GlobalValue *AliasedGV = GA->getAliasedGlobal();
    248     if (isa<Function>(AliasedGV))                          return 'T';
    249     if (isa<GlobalVariable>(AliasedGV))                    return 'D';
    250   }
    251                                                            return '?';
    252 }
    253 
    254 static void DumpSymbolNameForGlobalValue(GlobalValue &GV) {
    255   // Private linkage and available_externally linkage don't exist in symtab.
    256   if (GV.hasPrivateLinkage() ||
    257       GV.hasLinkerPrivateLinkage() ||
    258       GV.hasLinkerPrivateWeakLinkage() ||
    259       GV.hasLinkerPrivateWeakDefAutoLinkage() ||
    260       GV.hasAvailableExternallyLinkage())
    261     return;
    262   char TypeChar = TypeCharForSymbol(GV);
    263   if (GV.hasLocalLinkage () && ExternalOnly)
    264     return;
    265 
    266   NMSymbol s;
    267   s.Address = object::UnknownAddressOrSize;
    268   s.Size = object::UnknownAddressOrSize;
    269   s.TypeChar = TypeChar;
    270   s.Name     = GV.getName();
    271   SymbolList.push_back(s);
    272 }
    273 
    274 static void DumpSymbolNamesFromModule(Module *M) {
    275   CurrentFilename = M->getModuleIdentifier();
    276   std::for_each (M->begin(), M->end(), DumpSymbolNameForGlobalValue);
    277   std::for_each (M->global_begin(), M->global_end(),
    278                  DumpSymbolNameForGlobalValue);
    279   std::for_each (M->alias_begin(), M->alias_end(),
    280                  DumpSymbolNameForGlobalValue);
    281 
    282   SortAndPrintSymbolList();
    283 }
    284 
    285 static void DumpSymbolNamesFromObject(ObjectFile *obj) {
    286   error_code ec;
    287   symbol_iterator ibegin = obj->begin_symbols();
    288   symbol_iterator iend = obj->end_symbols();
    289   if (DynamicSyms) {
    290     ibegin = obj->begin_dynamic_symbols();
    291     iend = obj->end_dynamic_symbols();
    292   }
    293   for (symbol_iterator i = ibegin; i != iend; i.increment(ec)) {
    294     if (error(ec)) break;
    295     uint32_t symflags;
    296     if (error(i->getFlags(symflags))) break;
    297     if (!DebugSyms && (symflags & SymbolRef::SF_FormatSpecific))
    298       continue;
    299     NMSymbol s;
    300     s.Size = object::UnknownAddressOrSize;
    301     s.Address = object::UnknownAddressOrSize;
    302     if (PrintSize || SizeSort) {
    303       if (error(i->getSize(s.Size))) break;
    304     }
    305     if (PrintAddress)
    306       if (error(i->getAddress(s.Address))) break;
    307     if (error(i->getNMTypeChar(s.TypeChar))) break;
    308     if (error(i->getName(s.Name))) break;
    309     SymbolList.push_back(s);
    310   }
    311 
    312   CurrentFilename = obj->getFileName();
    313   SortAndPrintSymbolList();
    314 }
    315 
    316 static void DumpSymbolNamesFromFile(std::string &Filename) {
    317   if (Filename != "-" && !sys::fs::exists(Filename)) {
    318     errs() << ToolName << ": '" << Filename << "': " << "No such file\n";
    319     return;
    320   }
    321 
    322   OwningPtr<MemoryBuffer> Buffer;
    323   if (error(MemoryBuffer::getFileOrSTDIN(Filename, Buffer), Filename))
    324     return;
    325 
    326   sys::fs::file_magic magic = sys::fs::identify_magic(Buffer->getBuffer());
    327 
    328   LLVMContext &Context = getGlobalContext();
    329   std::string ErrorMessage;
    330   if (magic == sys::fs::file_magic::bitcode) {
    331     Module *Result = 0;
    332     Result = ParseBitcodeFile(Buffer.get(), Context, &ErrorMessage);
    333     if (Result) {
    334       DumpSymbolNamesFromModule(Result);
    335       delete Result;
    336     } else {
    337       error(ErrorMessage, Filename);
    338       return;
    339     }
    340   } else if (magic == sys::fs::file_magic::archive) {
    341     OwningPtr<Binary> arch;
    342     if (error(object::createBinary(Buffer.take(), arch), Filename))
    343       return;
    344 
    345     if (object::Archive *a = dyn_cast<object::Archive>(arch.get())) {
    346       for (object::Archive::child_iterator i = a->begin_children(),
    347                                            e = a->end_children(); i != e; ++i) {
    348         OwningPtr<Binary> child;
    349         if (i->getAsBinary(child)) {
    350           // Try opening it as a bitcode file.
    351           OwningPtr<MemoryBuffer> buff(i->getBuffer());
    352           Module *Result = 0;
    353           if (buff)
    354             Result = ParseBitcodeFile(buff.get(), Context, &ErrorMessage);
    355 
    356           if (Result) {
    357             DumpSymbolNamesFromModule(Result);
    358             delete Result;
    359           }
    360           continue;
    361         }
    362         if (object::ObjectFile *o = dyn_cast<ObjectFile>(child.get())) {
    363           outs() << o->getFileName() << ":\n";
    364           DumpSymbolNamesFromObject(o);
    365         }
    366       }
    367     }
    368   } else if (magic.is_object()) {
    369     OwningPtr<Binary> obj;
    370     if (error(object::createBinary(Buffer.take(), obj), Filename))
    371       return;
    372     if (object::ObjectFile *o = dyn_cast<ObjectFile>(obj.get()))
    373       DumpSymbolNamesFromObject(o);
    374   } else {
    375     errs() << ToolName << ": " << Filename << ": "
    376            << "unrecognizable file type\n";
    377     return;
    378   }
    379 }
    380 
    381 int main(int argc, char **argv) {
    382   // Print a stack trace if we signal out.
    383   sys::PrintStackTraceOnErrorSignal();
    384   PrettyStackTraceProgram X(argc, argv);
    385 
    386   llvm_shutdown_obj Y;  // Call llvm_shutdown() on exit.
    387   cl::ParseCommandLineOptions(argc, argv, "llvm symbol table dumper\n");
    388 
    389   // llvm-nm only reads binary files.
    390   if (error(sys::Program::ChangeStdinToBinary()))
    391     return 1;
    392 
    393   ToolName = argv[0];
    394   if (BSDFormat) OutputFormat = bsd;
    395   if (POSIXFormat) OutputFormat = posix;
    396 
    397   // The relative order of these is important. If you pass --size-sort it should
    398   // only print out the size. However, if you pass -S --size-sort, it should
    399   // print out both the size and address.
    400   if (SizeSort && !PrintSize) PrintAddress = false;
    401   if (OutputFormat == sysv || SizeSort) PrintSize = true;
    402 
    403   switch (InputFilenames.size()) {
    404   case 0: InputFilenames.push_back("-");
    405   case 1: break;
    406   default: MultipleFiles = true;
    407   }
    408 
    409   std::for_each(InputFilenames.begin(), InputFilenames.end(),
    410                 DumpSymbolNamesFromFile);
    411   return 0;
    412 }
    413