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"
22using namespace llvm;
23
24Linker::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
33Linker::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
41Linker::~Linker() {
42  delete Composite;
43}
44
45bool
46Linker::error(StringRef message) {
47  Error = message;
48  if (!(Flags&QuietErrors))
49    errs() << ProgramName << ": error: " << message << "\n";
50  return true;
51}
52
53bool
54Linker::warning(StringRef message) {
55  Error = message;
56  if (!(Flags&QuietWarnings))
57    errs() << ProgramName << ": warning: " << message << "\n";
58  return false;
59}
60
61void
62Linker::verbose(StringRef message) {
63  if (Flags&Verbose)
64    errs() << "  " << message << "\n";
65}
66
67void
68Linker::addPath(const sys::Path& path) {
69  LibPaths.push_back(path);
70}
71
72void
73Linker::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
78void
79Linker::addSystemPaths() {
80  sys::Path::GetBitcodeLibraryPaths(LibPaths);
81  LibPaths.insert(LibPaths.begin(),sys::Path("./"));
82}
83
84Module*
85Linker::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.
97std::auto_ptr<Module>
98Linker::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.
119static 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  // Try libX form, to make it possible to add dependency on the
145  // specific version of .so, like liblzma.so.1.0.0
146  FullPath.eraseSuffix();
147  if (FullPath.isDynamicLibrary())  // Native shared library?
148    return FullPath;
149  if (FullPath.isBitcodeFile())    // .so file containing bitcode?
150    return FullPath;
151
152  // Not found .. fall through
153
154  // Indicate that the library was not found in the directory.
155  FullPath.clear();
156  return FullPath;
157}
158
159/// FindLib - Try to convert Filename into the name of a file that we can open,
160/// if it does not already name a file we can open, by first trying to open
161/// Filename, then libFilename.[suffix] for each of a set of several common
162/// library suffixes, in each of the directories in LibPaths. Returns an empty
163/// Path if no matching file can be found.
164///
165sys::Path
166Linker::FindLib(StringRef Filename) {
167  // Determine if the pathname can be found as it stands.
168  sys::Path FilePath(Filename);
169  if (FilePath.canRead() &&
170      (FilePath.isArchive() || FilePath.isDynamicLibrary()))
171    return FilePath;
172
173  // Iterate over the directories in Paths to see if we can find the library
174  // there.
175  for (unsigned Index = 0; Index != LibPaths.size(); ++Index) {
176    sys::Path Directory(LibPaths[Index]);
177    sys::Path FullPath = IsLibrary(Filename, Directory);
178    if (!FullPath.isEmpty())
179      return FullPath;
180  }
181  return sys::Path();
182}
183