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