llvm-link.cpp revision 1ee1e64293dc1727c0119530ae4bc72006879954 
1//===- llvm-link.cpp - Low-level LLVM linker ------------------------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file was developed by the LLVM research group and is distributed under
6// the University of Illinois Open Source License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This utility may be invoked in the following manner:
11//  llvm-link a.bc b.bc c.bc -o x.bc
12//
13//===----------------------------------------------------------------------===//
14
15#include "llvm/Module.h"
16#include "llvm/Analysis/Verifier.h"
17#include "llvm/Bytecode/Reader.h"
18#include "llvm/Bytecode/Writer.h"
19#include "llvm/Transforms/Utils/Linker.h"
20#include "Support/CommandLine.h"
21#include "Support/Signals.h"
22#include <fstream>
23#include <memory>
24#include <sys/types.h>     // For FileExists
25#include <sys/stat.h>
26
27static cl::list<std::string>
28InputFilenames(cl::Positional, cl::OneOrMore,
29               cl::desc("<input bytecode files>"));
30
31static cl::opt<std::string>
32OutputFilename("o", cl::desc("Override output filename"), cl::init("-"),
33               cl::value_desc("filename"));
34
35static cl::opt<bool> Force("f", cl::desc("Overwrite output files"));
36
37static cl::opt<bool>
38Verbose("v", cl::desc("Print information about actions taken"));
39
40static cl::opt<bool>
41DumpAsm("d", cl::desc("Print assembly as linked"), cl::Hidden);
42
43static cl::list<std::string>
44LibPaths("L", cl::desc("Specify a library search path"), cl::ZeroOrMore,
45         cl::value_desc("directory"), cl::Prefix);
46
47// FileExists - Return true if the specified string is an openable file...
48static inline bool FileExists(const std::string &FN) {
49  struct stat StatBuf;
50  return stat(FN.c_str(), &StatBuf) != -1;
51}
52
53// LoadFile - Read the specified bytecode file in and return it.  This routine
54// searches the link path for the specified file to try to find it...
55//
56static inline std::auto_ptr<Module> LoadFile(const std::string &FN) {
57  std::string Filename = FN;
58  std::string ErrorMessage;
59
60  unsigned NextLibPathIdx = 0;
61  bool FoundAFile = false;
62
63  while (1) {
64    if (Verbose) std::cerr << "Loading '" << Filename << "'\n";
65    if (FileExists(Filename)) FoundAFile = true;
66    Module *Result = ParseBytecodeFile(Filename, &ErrorMessage);
67    if (Result) return std::auto_ptr<Module>(Result);   // Load successful!
68
69    if (Verbose) {
70      std::cerr << "Error opening bytecode file: '" << Filename << "'";
71      if (ErrorMessage.size()) std::cerr << ": " << ErrorMessage;
72      std::cerr << "\n";
73    }
74
75    if (NextLibPathIdx == LibPaths.size()) break;
76    Filename = LibPaths[NextLibPathIdx++] + "/" + FN;
77  }
78
79  if (FoundAFile)
80    std::cerr << "Bytecode file '" << FN << "' corrupt!  "
81              << "Use 'llvm-link -v ...' for more info.\n";
82  else
83    std::cerr << "Could not locate bytecode file: '" << FN << "'\n";
84  return std::auto_ptr<Module>();
85}
86
87
88
89
90int main(int argc, char **argv) {
91  cl::ParseCommandLineOptions(argc, argv, " llvm linker\n");
92  assert(InputFilenames.size() > 0 && "OneOrMore is not working");
93
94  unsigned BaseArg = 0;
95  std::string ErrorMessage;
96
97  std::auto_ptr<Module> Composite(LoadFile(InputFilenames[BaseArg]));
98  if (Composite.get() == 0) return 1;
99
100  for (unsigned i = BaseArg+1; i < InputFilenames.size(); ++i) {
101    std::auto_ptr<Module> M(LoadFile(InputFilenames[i]));
102    if (M.get() == 0) return 1;
103
104    if (Verbose) std::cerr << "Linking in '" << InputFilenames[i] << "'\n";
105
106    if (LinkModules(Composite.get(), M.get(), &ErrorMessage)) {
107      std::cerr << argv[0] << ": error linking in '" << InputFilenames[i]
108                << "': " << ErrorMessage << "\n";
109      return 1;
110    }
111  }
112
113  if (DumpAsm) std::cerr << "Here's the assembly:\n" << Composite.get();
114
115  std::ostream *Out = &std::cout;  // Default to printing to stdout...
116  if (OutputFilename != "-") {
117    if (!Force && std::ifstream(OutputFilename.c_str())) {
118      // If force is not specified, make sure not to overwrite a file!
119      std::cerr << argv[0] << ": error opening '" << OutputFilename
120                << "': file exists!\n"
121                << "Use -f command line argument to force output\n";
122      return 1;
123    }
124    Out = new std::ofstream(OutputFilename.c_str());
125    if (!Out->good()) {
126      std::cerr << argv[0] << ": error opening '" << OutputFilename << "'!\n";
127      return 1;
128    }
129
130    // Make sure that the Out file gets unlinked from the disk if we get a
131    // SIGINT
132    RemoveFileOnSignal(OutputFilename);
133  }
134
135  if (verifyModule(*Composite.get())) {
136    std::cerr << argv[0] << ": linked module is broken!\n";
137    return 1;
138  }
139
140  if (Verbose) std::cerr << "Writing bytecode...\n";
141  WriteBytecodeToFile(Composite.get(), *Out);
142
143  if (Out != &std::cout) delete Out;
144  return 0;
145}
146