LinkItems.cpp revision fc82ef67971403c01f19e672b6af8d2a5caf8a30 
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
18using namespace llvm;
19
20// LinkItems - preserve link order for an arbitrary set of linkage items.
21bool
22Linker::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///
52bool 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///
85bool 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///
119bool 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///
158bool 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}
164