lib/Linker/LinkItems.cpp

   1 //===- lib/Linker/LinkItems.cpp - Link LLVM objects and libraries ---------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file was developed by Reid Spencer and is distributed under the
   6 // University of Illinois Open Source License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // This file contains routines to handle linking together LLVM bytecode files,
  11 // and to handle annoying things like static libraries.
  12 //
  13 //===----------------------------------------------------------------------===//
  14
  15 #include "llvm/Linker.h"
  16 #include "llvm/Module.h"
  17
  18 using namespace llvm;
  19
  20 // LinkItems - preserve link order for an arbitrary set of linkage items.
  21 bool
  22 Linker::LinkInItems(const ItemList& Items) {
  23   // For each linkage item ...
  24   for (ItemList::const_iterator I = Items.begin(), E = Items.end();
  25        I != E; ++I) {
  26     if (I->second) {
  27       // Link in the library suggested.
  28       if (LinkInLibrary(I->first))
  29         return true;
  30     } else {
  31       if (LinkInFile(sys::Path(I->first)))
  32         return true;
  33     }
  34   }
  35
  36   // At this point we have processed all the link items provided to us. Since
  37   // we have an aggregated module at this point, the dependent libraries in
  38   // that module should also be aggregated with duplicates eliminated. This is
  39   // now the time to process the dependent libraries to resolve any remaining
  40   // symbols.
  41   for (Module::lib_iterator I = Composite->lib_begin(),
  42          E = Composite->lib_end(); I != E; ++I)
  43     if(LinkInLibrary(*I))
  44       return true;
  45
  46   return false;
  47 }
  48
  49
  50 /// LinkInLibrary - links one library into the HeadModule.
  51 ///
  52 bool Linker::LinkInLibrary(const std::string& Lib) {
  53   // Determine where this library lives.
  54   sys::Path Pathname = FindLib(Lib);
  55   if (Pathname.isEmpty())
  56     return warning("Cannot find library '" + Lib + "'");
  57
  58   // If its an archive, try to link it in
  59   if (Pathname.isArchive()) {
  60     if (LinkInArchive(Pathname))
  61       return error("Cannot link archive '" + Pathname.toString() + "'");
  62   } else if (Pathname.isBytecodeFile()) {
  63     // LLVM ".so" file.
  64     if (LinkInFile(Pathname))
  65       return error("Cannot link file '" + Pathname.toString() + "'");
  66
  67   } else if (Pathname.isDynamicLibrary()) {
  68     return warning("Library '" + Lib + "' is a native dynamic library.");
  69   } else {
  70     return warning("Supposed library '" + Lib + "' isn't a library.");
  71   }
  72   return false;
  73 }
  74
  75 /// LinkLibraries - takes the specified library files and links them into the
  76 /// main bytecode object file.
  77 ///
  78 /// Inputs:
  79 ///  Libraries  - The list of libraries to link into the module.
  80 ///
  81 /// Return value:
  82 ///  FALSE - No error.
  83 ///  TRUE  - Error.
  84 ///
  85 bool Linker::LinkInLibraries(const std::vector<std::string> &Libraries) {
  86
  87   // Process the set of libraries we've been provided.
  88   for (unsigned i = 0; i < Libraries.size(); ++i)
  89     if (LinkInLibrary(Libraries[i]))
  90       return true;
  91
  92   // At this point we have processed all the libraries provided to us. Since
  93   // we have an aggregated module at this point, the dependent libraries in
  94   // that module should also be aggregated with duplicates eliminated. This is
  95   // now the time to process the dependent libraries to resolve any remaining
  96   // symbols.
  97   const Module::LibraryListType& DepLibs = Composite->getLibraries();
  98   for (Module::LibraryListType::const_iterator I = DepLibs.begin(),
  99          E = DepLibs.end(); I != E; ++I)
 100     if (LinkInLibrary(*I))
 101       return true;
 102
 103   return false;
 104 }
 105
 106 /// LinkInFile - opens a bytecode file and links in all objects which
 107 /// provide symbols that are currently undefined.
 108 ///
 109 /// Inputs:
 110 ///  File - The pathname of the bytecode file.
 111 ///
 112 /// Outputs:
 113 ///  ErrorMessage - A C++ string detailing what error occurred, if any.
 114 ///
 115 /// Return Value:
 116 ///  TRUE  - An error occurred.
 117 ///  FALSE - No errors.
 118 ///
 119 bool Linker::LinkInFile(const sys::Path &File) {
 120   // Make sure we can at least read the file
 121   if (!File.readable())
 122     return error("Cannot find linker input '" + File.toString() + "'");
 123
 124   // A user may specify an ar archive without -l, perhaps because it
 125   // is not installed as a library. Detect that and link the library.
 126   if (File.isArchive()) {
 127     if (LinkInArchive(File))
 128       return error("Cannot link archive '" + File.toString() + "'");
 129   } else if (File.isBytecodeFile()) {
 130     verbose("Linking bytecode file '" + File.toString() + "'");
 131
 132     std::auto_ptr<Module> M(LoadObject(File));
 133     if (M.get() == 0)
 134       return error("Cannot load file '" + File.toString() + "'" + Error);
 135     if (LinkInModule(M.get()))
 136       return error("Cannot link file '" + File.toString() + "'" + Error);
 137
 138     verbose("Linked in file '" + File.toString() + "'");
 139   } else {
 140     return warning("File of unknown type '" + File.toString() + "' ignored.");
 141   }
 142   return false;
 143 }
 144
 145 /// LinkFiles - takes a module and a list of files and links them all together.
 146 /// It locates the file either in the current directory, as its absolute
 147 /// or relative pathname, or as a file somewhere in LLVM_LIB_SEARCH_PATH.
 148 ///
 149 /// Inputs:
 150 ///  Files      - A vector of sys::Path indicating the LLVM bytecode filenames
 151 ///               to be linked.  The names can refer to a mixture of pure LLVM
 152 ///               bytecode files and archive (ar) formatted files.
 153 ///
 154 /// Return value:
 155 ///  FALSE - No errors.
 156 ///  TRUE  - Some error occurred.
 157 ///
 158 bool Linker::LinkInFiles(const std::vector<sys::Path> &Files) {
 159   for (unsigned i = 0; i < Files.size(); ++i)
 160     if (LinkInFile(Files[i]))
 161       return true;
 162   return false;
 163 }