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/Support/CommandLine.h"
24 #include "llvm/Support/ManagedStatic.h"
25 #include "llvm/Support/MemoryBuffer.h"
26 #include "llvm/Support/PrettyStackTrace.h"
27 #include "llvm/Support/raw_ostream.h"
28 #include "llvm/System/Signals.h"
29 #include <algorithm>
30 #include <cctype>
31 #include <cerrno>
32 #include <cstring>
33 using namespace llvm;
34 
35 namespace {
36   enum OutputFormatTy { bsd, sysv, posix };
37   cl::opt<OutputFormatTy>
38   OutputFormat("format",
39        cl::desc("Specify output format"),
40          cl::values(clEnumVal(bsd,   "BSD format"),
41                     clEnumVal(sysv,  "System V format"),
42                     clEnumVal(posix, "POSIX.2 format"),
43                     clEnumValEnd), cl::init(bsd));
44   cl::alias OutputFormat2("f", cl::desc("Alias for --format"),
45                           cl::aliasopt(OutputFormat));
46 
47   cl::list<std::string>
48   InputFilenames(cl::Positional, cl::desc("<input bitcode files>"),
49                  cl::ZeroOrMore);
50 
51   cl::opt<bool> UndefinedOnly("undefined-only",
52                               cl::desc("Show only undefined symbols"));
53   cl::alias UndefinedOnly2("u", cl::desc("Alias for --undefined-only"),
54                            cl::aliasopt(UndefinedOnly));
55 
56   cl::opt<bool> DefinedOnly("defined-only",
57                             cl::desc("Show only defined symbols"));
58 
59   cl::opt<bool> ExternalOnly("extern-only",
60                              cl::desc("Show only external symbols"));
61   cl::alias ExternalOnly2("g", cl::desc("Alias for --extern-only"),
62                           cl::aliasopt(ExternalOnly));
63 
64   cl::opt<bool> BSDFormat("B", cl::desc("Alias for --format=bsd"));
65   cl::opt<bool> POSIXFormat("P", cl::desc("Alias for --format=posix"));
66 
67   bool MultipleFiles = false;
68 
69   std::string ToolName;
70 }
71 
72 static char TypeCharForSymbol(GlobalValue &GV) {
73   if (GV.isDeclaration())                                  return 'U';
74   if (GV.hasLinkOnceLinkage())                             return 'C';
75   if (GV.hasCommonLinkage())                               return 'C';
76   if (GV.hasWeakLinkage())                                 return 'W';
77   if (isa<Function>(GV) && GV.hasInternalLinkage())        return 't';
78   if (isa<Function>(GV))                                   return 'T';
79   if (isa<GlobalVariable>(GV) && GV.hasInternalLinkage())  return 'd';
80   if (isa<GlobalVariable>(GV))                             return 'D';
81   if (const GlobalAlias *GA = dyn_cast<GlobalAlias>(&GV)) {
82     const GlobalValue *AliasedGV = GA->getAliasedGlobal();
83     if (isa<Function>(AliasedGV))                          return 'T';
84     if (isa<GlobalVariable>(AliasedGV))                    return 'D';
85   }
86                                                            return '?';
87 }
88 
89 static void DumpSymbolNameForGlobalValue(GlobalValue &GV) {
90   // Private linkage and available_externally linkage don't exist in symtab.
91   if (GV.hasPrivateLinkage() || GV.hasLinkerPrivateLinkage() ||
92       GV.hasAvailableExternallyLinkage()) return;
93 
94   const std::string SymbolAddrStr = "        "; // Not used yet...
95   char TypeChar = TypeCharForSymbol(GV);
96   if ((TypeChar != 'U') && UndefinedOnly)
97     return;
98   if ((TypeChar == 'U') && DefinedOnly)
99     return;
100   if (GV.hasLocalLinkage () && ExternalOnly)
101     return;
102   if (OutputFormat == posix) {
103     outs() << GV.getName () << " " << TypeCharForSymbol(GV) << " "
104            << SymbolAddrStr << "\n";
105   } else if (OutputFormat == bsd) {
106     outs() << SymbolAddrStr << " " << TypeCharForSymbol(GV) << " "
107            << GV.getName () << "\n";
108   } else if (OutputFormat == sysv) {
109     std::string PaddedName (GV.getName ());
110     while (PaddedName.length () < 20)
111       PaddedName += " ";
112     outs() << PaddedName << "|" << SymbolAddrStr << "|   "
113            << TypeCharForSymbol(GV)
114            << "  |                  |      |     |\n";
115   }
116 }
117 
118 static void DumpSymbolNamesFromModule(Module *M) {
119   const std::string &Filename = M->getModuleIdentifier ();
120   if (OutputFormat == posix && MultipleFiles) {
121     outs() << Filename << ":\n";
122   } else if (OutputFormat == bsd && MultipleFiles) {
123     outs() << "\n" << Filename << ":\n";
124   } else if (OutputFormat == sysv) {
125     outs() << "\n\nSymbols from " << Filename << ":\n\n"
126            << "Name                  Value   Class        Type"
127            << "         Size   Line  Section\n";
128   }
129   std::for_each (M->begin(), M->end(), DumpSymbolNameForGlobalValue);
130   std::for_each (M->global_begin(), M->global_end(),
131                  DumpSymbolNameForGlobalValue);
132   std::for_each (M->alias_begin(), M->alias_end(),
133                  DumpSymbolNameForGlobalValue);
134 }
135 
136 static void DumpSymbolNamesFromFile(std::string &Filename) {
137   LLVMContext &Context = getGlobalContext();
138   std::string ErrorMessage;
139   sys::Path aPath(Filename);
140   // Note: Currently we do not support reading an archive from stdin.
141   if (Filename == "-" || aPath.isBitcodeFile()) {
142     std::auto_ptr<MemoryBuffer> Buffer(
143                    MemoryBuffer::getFileOrSTDIN(Filename, &ErrorMessage));
144     Module *Result = 0;
145     if (Buffer.get())
146       Result = ParseBitcodeFile(Buffer.get(), Context, &ErrorMessage);
147 
148     if (Result)
149       DumpSymbolNamesFromModule(Result);
150     else {
151       errs() << ToolName << ": " << Filename << ": " << ErrorMessage << "\n";
152       return;
153     }
154 
155   } else if (aPath.isArchive()) {
156     std::string ErrMsg;
157     Archive* archive = Archive::OpenAndLoad(sys::Path(Filename), Context,
158                                             &ErrorMessage);
159     if (!archive)
160       errs() << ToolName << ": " << Filename << ": " << ErrorMessage << "\n";
161     std::vector<Module *> Modules;
162     if (archive->getAllModules(Modules, &ErrorMessage)) {
163       errs() << ToolName << ": " << Filename << ": " << ErrorMessage << "\n";
164       return;
165     }
166     MultipleFiles = true;
167     std::for_each (Modules.begin(), Modules.end(), DumpSymbolNamesFromModule);
168   } else {
169     errs() << ToolName << ": " << Filename << ": "
170            << "unrecognizable file type\n";
171     return;
172   }
173 }
174 
175 int main(int argc, char **argv) {
176   // Print a stack trace if we signal out.
177   sys::PrintStackTraceOnErrorSignal();
178   PrettyStackTraceProgram X(argc, argv);
179 
180   llvm_shutdown_obj Y;  // Call llvm_shutdown() on exit.
181   cl::ParseCommandLineOptions(argc, argv, "llvm symbol table dumper\n");
182 
183   ToolName = argv[0];
184   if (BSDFormat) OutputFormat = bsd;
185   if (POSIXFormat) OutputFormat = posix;
186 
187   switch (InputFilenames.size()) {
188   case 0: InputFilenames.push_back("-");
189   case 1: break;
190   default: MultipleFiles = true;
191   }
192 
193   std::for_each(InputFilenames.begin(), InputFilenames.end(),
194                 DumpSymbolNamesFromFile);
195   return 0;
196 }
197