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/Linker.h"
16#include "llvm/Bitcode/ReaderWriter.h"
17#include "llvm/IR/LLVMContext.h"
18#include "llvm/IR/Module.h"
19#include "llvm/IR/Verifier.h"
20#include "llvm/IRReader/IRReader.h"
21#include "llvm/Support/CommandLine.h"
22#include "llvm/Support/FileSystem.h"
23#include "llvm/Support/ManagedStatic.h"
24#include "llvm/Support/Path.h"
25#include "llvm/Support/PrettyStackTrace.h"
26#include "llvm/Support/Signals.h"
27#include "llvm/Support/SourceMgr.h"
28#include "llvm/Support/SystemUtils.h"
29#include "llvm/Support/ToolOutputFile.h"
30#include <memory>
31using namespace llvm;
32
33static cl::list<std::string>
34InputFilenames(cl::Positional, cl::OneOrMore,
35               cl::desc("<input bitcode files>"));
36
37static cl::opt<std::string>
38OutputFilename("o", cl::desc("Override output filename"), cl::init("-"),
39               cl::value_desc("filename"));
40
41static cl::opt<bool>
42Force("f", cl::desc("Enable binary output on terminals"));
43
44static cl::opt<bool>
45OutputAssembly("S",
46         cl::desc("Write output as LLVM assembly"), cl::Hidden);
47
48static cl::opt<bool>
49Verbose("v", cl::desc("Print information about actions taken"));
50
51static cl::opt<bool>
52DumpAsm("d", cl::desc("Print assembly as linked"), cl::Hidden);
53
54static cl::opt<bool>
55SuppressWarnings("suppress-warnings", cl::desc("Suppress all linking warnings"),
56                 cl::init(false));
57
58// LoadFile - Read the specified bitcode file in and return it.  This routine
59// searches the link path for the specified file to try to find it...
60//
61static inline Module *LoadFile(const char *argv0, const std::string &FN,
62                               LLVMContext& Context) {
63  SMDiagnostic Err;
64  if (Verbose) errs() << "Loading '" << FN << "'\n";
65  Module* Result = nullptr;
66
67  Result = ParseIRFile(FN, Err, Context);
68  if (Result) return Result;   // Load successful!
69
70  Err.print(argv0, errs());
71  return nullptr;
72}
73
74int main(int argc, char **argv) {
75  // Print a stack trace if we signal out.
76  sys::PrintStackTraceOnErrorSignal();
77  PrettyStackTraceProgram X(argc, argv);
78
79  LLVMContext &Context = getGlobalContext();
80  llvm_shutdown_obj Y;  // Call llvm_shutdown() on exit.
81  cl::ParseCommandLineOptions(argc, argv, "llvm linker\n");
82
83  unsigned BaseArg = 0;
84  std::string ErrorMessage;
85
86  std::unique_ptr<Module> Composite(
87      LoadFile(argv[0], InputFilenames[BaseArg], Context));
88  if (!Composite.get()) {
89    errs() << argv[0] << ": error loading file '"
90           << InputFilenames[BaseArg] << "'\n";
91    return 1;
92  }
93
94  Linker L(Composite.get(), SuppressWarnings);
95  for (unsigned i = BaseArg+1; i < InputFilenames.size(); ++i) {
96    std::unique_ptr<Module> M(LoadFile(argv[0], InputFilenames[i], Context));
97    if (!M.get()) {
98      errs() << argv[0] << ": error loading file '" <<InputFilenames[i]<< "'\n";
99      return 1;
100    }
101
102    if (Verbose) errs() << "Linking in '" << InputFilenames[i] << "'\n";
103
104    if (L.linkInModule(M.get(), &ErrorMessage)) {
105      errs() << argv[0] << ": link error in '" << InputFilenames[i]
106             << "': " << ErrorMessage << "\n";
107      return 1;
108    }
109  }
110
111  if (DumpAsm) errs() << "Here's the assembly:\n" << *Composite;
112
113  std::string ErrorInfo;
114  tool_output_file Out(OutputFilename.c_str(), ErrorInfo, sys::fs::F_None);
115  if (!ErrorInfo.empty()) {
116    errs() << ErrorInfo << '\n';
117    return 1;
118  }
119
120  if (verifyModule(*Composite)) {
121    errs() << argv[0] << ": linked module is broken!\n";
122    return 1;
123  }
124
125  if (Verbose) errs() << "Writing bitcode...\n";
126  if (OutputAssembly) {
127    Out.os() << *Composite;
128  } else if (Force || !CheckBitcodeOutputToConsole(Out.os(), true))
129    WriteBitcodeToFile(Composite.get(), Out.os());
130
131  // Declare success.
132  Out.keep();
133
134  return 0;
135}
136