llvm-link.cpp revision 195340 
1//===- llvm-link.cpp - Low-level LLVM linker ------------------------------===//
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 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/Linker.h"
16#include "llvm/LLVMContext.h"
17#include "llvm/Module.h"
18#include "llvm/Analysis/Verifier.h"
19#include "llvm/Bitcode/ReaderWriter.h"
20#include "llvm/Support/CommandLine.h"
21#include "llvm/Support/ManagedStatic.h"
22#include "llvm/Support/MemoryBuffer.h"
23#include "llvm/Support/PrettyStackTrace.h"
24#include "llvm/Support/Streams.h"
25#include "llvm/System/Signals.h"
26#include "llvm/System/Path.h"
27#include <fstream>
28#include <iostream>
29#include <memory>
30using namespace llvm;
31
32static cl::list<std::string>
33InputFilenames(cl::Positional, cl::OneOrMore,
34               cl::desc("<input bitcode files>"));
35
36static cl::opt<std::string>
37OutputFilename("o", cl::desc("Override output filename"), cl::init("-"),
38               cl::value_desc("filename"));
39
40static cl::opt<bool> Force("f", cl::desc("Overwrite output files"));
41
42static cl::opt<bool>
43Verbose("v", cl::desc("Print information about actions taken"));
44
45static cl::opt<bool>
46DumpAsm("d", cl::desc("Print assembly as linked"), cl::Hidden);
47
48// LoadFile - Read the specified bitcode file in and return it.  This routine
49// searches the link path for the specified file to try to find it...
50//
51static inline std::auto_ptr<Module> LoadFile(const std::string &FN,
52                                             LLVMContext& Context) {
53  sys::Path Filename;
54  if (!Filename.set(FN)) {
55    cerr << "Invalid file name: '" << FN << "'\n";
56    return std::auto_ptr<Module>();
57  }
58
59  std::string ErrorMessage;
60  if (Filename.exists()) {
61    if (Verbose) cerr << "Loading '" << Filename.c_str() << "'\n";
62    Module* Result = 0;
63
64    const std::string &FNStr = Filename.toString();
65    if (MemoryBuffer *Buffer = MemoryBuffer::getFileOrSTDIN(FNStr,
66                                                            &ErrorMessage)) {
67      Result = ParseBitcodeFile(Buffer, Context, &ErrorMessage);
68      delete Buffer;
69    }
70    if (Result) return std::auto_ptr<Module>(Result);   // Load successful!
71
72    if (Verbose) {
73      cerr << "Error opening bitcode file: '" << Filename.c_str() << "'";
74      if (ErrorMessage.size()) cerr << ": " << ErrorMessage;
75      cerr << "\n";
76    }
77  } else {
78    cerr << "Bitcode file: '" << Filename.c_str() << "' does not exist.\n";
79  }
80
81  return std::auto_ptr<Module>();
82}
83
84int main(int argc, char **argv) {
85  // Print a stack trace if we signal out.
86  sys::PrintStackTraceOnErrorSignal();
87  PrettyStackTraceProgram X(argc, argv);
88
89  LLVMContext Context;
90  llvm_shutdown_obj Y;  // Call llvm_shutdown() on exit.
91  cl::ParseCommandLineOptions(argc, argv, "llvm linker\n");
92
93  unsigned BaseArg = 0;
94  std::string ErrorMessage;
95
96  std::auto_ptr<Module> Composite(LoadFile(InputFilenames[BaseArg], Context));
97  if (Composite.get() == 0) {
98    cerr << argv[0] << ": error loading file '"
99         << InputFilenames[BaseArg] << "'\n";
100    return 1;
101  }
102
103  for (unsigned i = BaseArg+1; i < InputFilenames.size(); ++i) {
104    std::auto_ptr<Module> M(LoadFile(InputFilenames[i], Context));
105    if (M.get() == 0) {
106      cerr << argv[0] << ": error loading file '" <<InputFilenames[i]<< "'\n";
107      return 1;
108    }
109
110    if (Verbose) cerr << "Linking in '" << InputFilenames[i] << "'\n";
111
112    if (Linker::LinkModules(Composite.get(), M.get(), &ErrorMessage)) {
113      cerr << argv[0] << ": link error in '" << InputFilenames[i]
114           << "': " << ErrorMessage << "\n";
115      return 1;
116    }
117  }
118
119  // TODO: Iterate over the -l list and link in any modules containing
120  // global symbols that have not been resolved so far.
121
122  if (DumpAsm) cerr << "Here's the assembly:\n" << *Composite.get();
123
124  // FIXME: cout is not binary!
125  std::ostream *Out = &std::cout;  // Default to printing to stdout...
126  if (OutputFilename != "-") {
127    if (!Force && std::ifstream(OutputFilename.c_str())) {
128      // If force is not specified, make sure not to overwrite a file!
129      cerr << argv[0] << ": error opening '" << OutputFilename
130           << "': file exists!\n"
131           << "Use -f command line argument to force output\n";
132      return 1;
133    }
134    std::ios::openmode io_mode = std::ios::out | std::ios::trunc |
135                                 std::ios::binary;
136    Out = new std::ofstream(OutputFilename.c_str(), io_mode);
137    if (!Out->good()) {
138      cerr << argv[0] << ": error opening '" << OutputFilename << "'!\n";
139      return 1;
140    }
141
142    // Make sure that the Out file gets unlinked from the disk if we get a
143    // SIGINT
144    sys::RemoveFileOnSignal(sys::Path(OutputFilename));
145  }
146
147  if (verifyModule(*Composite.get())) {
148    cerr << argv[0] << ": linked module is broken!\n";
149    return 1;
150  }
151
152  if (Verbose) cerr << "Writing bitcode...\n";
153  WriteBitcodeToFile(Composite.get(), *Out);
154
155  if (Out != &std::cout) delete Out;
156  return 0;
157}
158