lib/Linker/Linker.cpp

   1 //===- lib/Linker/Linker.cpp - Basic Linker functionality  ----------------===//
   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 file contains basic Linker functionality that all usages will need.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "llvm/Linker.h"
  15 #include "llvm/Module.h"
  16 #include "llvm/Bitcode/ReaderWriter.h"
  17 #include "llvm/Support/Path.h"
  18 #include "llvm/Support/MemoryBuffer.h"
  19 #include "llvm/Support/raw_ostream.h"
  20 #include "llvm/Config/config.h"
  21 #include "llvm/Support/system_error.h"
  22 using namespace llvm;
  23
  24 Linker::Linker(StringRef progname, StringRef modname,
  25                LLVMContext& C, unsigned flags):
  26   Context(C),
  27   Composite(new Module(modname, C)),
  28   LibPaths(),
  29   Flags(flags),
  30   Error(),
  31   ProgramName(progname) { }
  32
  33 Linker::Linker(StringRef progname, Module* aModule, unsigned flags) :
  34   Context(aModule->getContext()),
  35   Composite(aModule),
  36   LibPaths(),
  37   Flags(flags),
  38   Error(),
  39   ProgramName(progname) { }
  40
  41 Linker::~Linker() {
  42   delete Composite;
  43 }
  44
  45 bool
  46 Linker::error(StringRef message) {
  47   Error = message;
  48   if (!(Flags&QuietErrors))
  49     errs() << ProgramName << ": error: " << message << "\n";
  50   return true;
  51 }
  52
  53 bool
  54 Linker::warning(StringRef message) {
  55   Error = message;
  56   if (!(Flags&QuietWarnings))
  57     errs() << ProgramName << ": warning: " << message << "\n";
  58   return false;
  59 }
  60
  61 void
  62 Linker::verbose(StringRef message) {
  63   if (Flags&Verbose)
  64     errs() << "  " << message << "\n";
  65 }
  66
  67 void
  68 Linker::addPath(const sys::Path& path) {
  69   LibPaths.push_back(path);
  70 }
  71
  72 void
  73 Linker::addPaths(const std::vector<std::string>& paths) {
  74   for (unsigned i = 0, e = paths.size(); i != e; ++i)
  75     LibPaths.push_back(sys::Path(paths[i]));
  76 }
  77
  78 void
  79 Linker::addSystemPaths() {
  80   sys::Path::GetBitcodeLibraryPaths(LibPaths);
  81   LibPaths.insert(LibPaths.begin(),sys::Path("./"));
  82 }
  83
  84 Module*
  85 Linker::releaseModule() {
  86   Module* result = Composite;
  87   LibPaths.clear();
  88   Error.clear();
  89   Composite = 0;
  90   Flags = 0;
  91   return result;
  92 }
  93
  94 // LoadObject - Read in and parse the bitcode file named by FN and return the
  95 // module it contains (wrapped in an auto_ptr), or auto_ptr<Module>() and set
  96 // Error if an error occurs.
  97 std::auto_ptr<Module>
  98 Linker::LoadObject(const sys::Path &FN) {
  99   std::string ParseErrorMessage;
 100   Module *Result = 0;
 101
 102   OwningPtr<MemoryBuffer> Buffer;
 103   if (error_code ec = MemoryBuffer::getFileOrSTDIN(FN.c_str(), Buffer))
 104     ParseErrorMessage = "Error reading file '" + FN.str() + "'" + ": "
 105                       + ec.message();
 106   else
 107     Result = ParseBitcodeFile(Buffer.get(), Context, &ParseErrorMessage);
 108
 109   if (Result)
 110     return std::auto_ptr<Module>(Result);
 111   Error = "Bitcode file '" + FN.str() + "' could not be loaded";
 112   if (ParseErrorMessage.size())
 113     Error += ": " + ParseErrorMessage;
 114   return std::auto_ptr<Module>();
 115 }
 116
 117 // IsLibrary - Determine if "Name" is a library in "Directory". Return
 118 // a non-empty sys::Path if its found, an empty one otherwise.
 119 static inline sys::Path IsLibrary(StringRef Name,
 120                                   const sys::Path &Directory) {
 121
 122   sys::Path FullPath(Directory);
 123
 124   // Try the libX.a form
 125   FullPath.appendComponent(("lib" + Name).str());
 126   FullPath.appendSuffix("a");
 127   if (FullPath.isArchive())
 128     return FullPath;
 129
 130   // Try the libX.bca form
 131   FullPath.eraseSuffix();
 132   FullPath.appendSuffix("bca");
 133   if (FullPath.isArchive())
 134     return FullPath;
 135
 136   // Try the libX.so (or .dylib) form
 137   FullPath.eraseSuffix();
 138   FullPath.appendSuffix(sys::Path::GetDLLSuffix());
 139   if (FullPath.isDynamicLibrary())  // Native shared library?
 140     return FullPath;
 141   if (FullPath.isBitcodeFile())    // .so file containing bitcode?
 142     return FullPath;
 143
 144   // Not found .. fall through
 145
 146   // Indicate that the library was not found in the directory.
 147   FullPath.clear();
 148   return FullPath;
 149 }
 150
 151 /// FindLib - Try to convert Filename into the name of a file that we can open,
 152 /// if it does not already name a file we can open, by first trying to open
 153 /// Filename, then libFilename.[suffix] for each of a set of several common
 154 /// library suffixes, in each of the directories in LibPaths. Returns an empty
 155 /// Path if no matching file can be found.
 156 ///
 157 sys::Path
 158 Linker::FindLib(StringRef Filename) {
 159   // Determine if the pathname can be found as it stands.
 160   sys::Path FilePath(Filename);
 161   if (FilePath.canRead() &&
 162       (FilePath.isArchive() || FilePath.isDynamicLibrary()))
 163     return FilePath;
 164
 165   // Iterate over the directories in Paths to see if we can find the library
 166   // there.
 167   for (unsigned Index = 0; Index != LibPaths.size(); ++Index) {
 168     sys::Path Directory(LibPaths[Index]);
 169     sys::Path FullPath = IsLibrary(Filename, Directory);
 170     if (!FullPath.isEmpty())
 171       return FullPath;
 172   }
 173   return sys::Path();
 174 }