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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"
22 using namespace llvm;
23 
Linker(StringRef progname,StringRef modname,LLVMContext & C,unsigned flags)24 Linker::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 
Linker(StringRef progname,Module * aModule,unsigned flags)33 Linker::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 
~Linker()41 Linker::~Linker() {
42   delete Composite;
43 }
44 
45 bool
error(StringRef message)46 Linker::error(StringRef message) {
47   Error = message;
48   if (!(Flags&QuietErrors))
49     errs() << ProgramName << ": error: " << message << "\n";
50   return true;
51 }
52 
53 bool
warning(StringRef message)54 Linker::warning(StringRef message) {
55   Error = message;
56   if (!(Flags&QuietWarnings))
57     errs() << ProgramName << ": warning: " << message << "\n";
58   return false;
59 }
60 
61 void
verbose(StringRef message)62 Linker::verbose(StringRef message) {
63   if (Flags&Verbose)
64     errs() << "  " << message << "\n";
65 }
66 
67 void
addPath(const sys::Path & path)68 Linker::addPath(const sys::Path& path) {
69   LibPaths.push_back(path);
70 }
71 
72 void
addPaths(const std::vector<std::string> & paths)73 Linker::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 
78 void
addSystemPaths()79 Linker::addSystemPaths() {
80   sys::Path::GetBitcodeLibraryPaths(LibPaths);
81   LibPaths.insert(LibPaths.begin(),sys::Path("./"));
82 }
83 
84 Module*
releaseModule()85 Linker::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.
97 std::auto_ptr<Module>
LoadObject(const sys::Path & FN)98 Linker::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.
IsLibrary(StringRef Name,const sys::Path & Directory)119 static 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 ///
165 sys::Path
FindLib(StringRef Filename)166 Linker::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