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/Config/config.h"
  18 #include "llvm/Support/MemoryBuffer.h"
  19 #include "llvm/Support/Streams.h"
  20 using namespace llvm;
  21
  22 Linker::Linker(const std::string& progname, const std::string& modname,
  23                unsigned flags)
  24   : Composite(0)
  25   , LibPaths()
  26   , Flags(flags)
  27   , Error()
  28   , ProgramName(progname)
  29 {
  30   Composite = new Module(modname);
  31 }
  32
  33 Linker::Linker(const std::string& progname, Module* aModule, unsigned flags)
  34   : Composite(aModule)
  35   , LibPaths()
  36   , Flags(flags)
  37   , Error()
  38   , ProgramName(progname)
  39 {
  40 }
  41
  42 Linker::~Linker() {
  43   delete Composite;
  44 }
  45
  46 bool
  47 Linker::error(const std::string& message) {
  48   Error = message;
  49   if (!(Flags&QuietErrors))
  50     cerr << ProgramName << ": error: " << message << "\n";
  51   return true;
  52 }
  53
  54 bool
  55 Linker::warning(const std::string& message) {
  56   Error = message;
  57   if (!(Flags&QuietWarnings))
  58     cerr << ProgramName << ": warning: " << message << "\n";
  59   return false;
  60 }
  61
  62 void
  63 Linker::verbose(const std::string& message) {
  64   if (Flags&Verbose)
  65     cerr << "  " << message << "\n";
  66 }
  67
  68 void
  69 Linker::addPath(const sys::Path& path) {
  70   LibPaths.push_back(path);
  71 }
  72
  73 void
  74 Linker::addPaths(const std::vector<std::string>& paths) {
  75   for (unsigned i = 0; i != paths.size(); ++i) {
  76     sys::Path aPath;
  77     aPath.set(paths[i]);
  78     LibPaths.push_back(aPath);
  79   }
  80 }
  81
  82 void
  83 Linker::addSystemPaths() {
  84   sys::Path::GetBitcodeLibraryPaths(LibPaths);
  85   LibPaths.insert(LibPaths.begin(),sys::Path("./"));
  86 }
  87
  88 Module*
  89 Linker::releaseModule() {
  90   Module* result = Composite;
  91   LibPaths.clear();
  92   Error.clear();
  93   Composite = 0;
  94   Flags = 0;
  95   return result;
  96 }
  97
  98 // LoadObject - Read in and parse the bitcode file named by FN and return the
  99 // module it contains (wrapped in an auto_ptr), or auto_ptr<Module>() and set
 100 // Error if an error occurs.
 101 std::auto_ptr<Module>
 102 Linker::LoadObject(const sys::Path &FN) {
 103   std::string ParseErrorMessage;
 104   Module *Result = 0;
 105
 106   const std::string &FNS = FN.toString();
 107   std::auto_ptr<MemoryBuffer> Buffer(MemoryBuffer::getFileOrSTDIN(FNS.c_str()));
 108   if (Buffer.get())
 109     Result = ParseBitcodeFile(Buffer.get(), &ParseErrorMessage);
 110   else
 111     ParseErrorMessage = "Error reading file '" + FNS + "'";
 112
 113   if (Result)
 114     return std::auto_ptr<Module>(Result);
 115   Error = "Bitcode file '" + FN.toString() + "' could not be loaded";
 116   if (ParseErrorMessage.size())
 117     Error += ": " + ParseErrorMessage;
 118   return std::auto_ptr<Module>();
 119 }
 120
 121 // IsLibrary - Determine if "Name" is a library in "Directory". Return
 122 // a non-empty sys::Path if its found, an empty one otherwise.
 123 static inline sys::Path IsLibrary(const std::string& Name,
 124                                   const sys::Path& Directory) {
 125
 126   sys::Path FullPath(Directory);
 127
 128   // Try the libX.a form
 129   FullPath.appendComponent("lib" + Name);
 130   FullPath.appendSuffix("a");
 131   if (FullPath.isArchive())
 132     return FullPath;
 133
 134   // Try the libX.bca form
 135   FullPath.eraseSuffix();
 136   FullPath.appendSuffix("bca");
 137   if (FullPath.isArchive())
 138     return FullPath;
 139
 140   // Try the libX.so (or .dylib) form
 141   FullPath.eraseSuffix();
 142   FullPath.appendSuffix(&(LTDL_SHLIB_EXT[1]));
 143   if (FullPath.isDynamicLibrary())  // Native shared library?
 144     return FullPath;
 145   if (FullPath.isBitcodeFile())    // .so file containing bitcode?
 146     return FullPath;
 147
 148   // Not found .. fall through
 149
 150   // Indicate that the library was not found in the directory.
 151   FullPath.clear();
 152   return FullPath;
 153 }
 154
 155 /// FindLib - Try to convert Filename into the name of a file that we can open,
 156 /// if it does not already name a file we can open, by first trying to open
 157 /// Filename, then libFilename.[suffix] for each of a set of several common
 158 /// library suffixes, in each of the directories in LibPaths. Returns an empty
 159 /// Path if no matching file can be found.
 160 ///
 161 sys::Path
 162 Linker::FindLib(const std::string &Filename) {
 163   // Determine if the pathname can be found as it stands.
 164   sys::Path FilePath(Filename);
 165   if (FilePath.canRead() &&
 166       (FilePath.isArchive() || FilePath.isDynamicLibrary()))
 167     return FilePath;
 168
 169   // Iterate over the directories in Paths to see if we can find the library
 170   // there.
 171   for (unsigned Index = 0; Index != LibPaths.size(); ++Index) {
 172     sys::Path Directory(LibPaths[Index]);
 173     sys::Path FullPath = IsLibrary(Filename,Directory);
 174     if (!FullPath.isEmpty())
 175       return FullPath;
 176   }
 177   return sys::Path();
 178 }