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