1 //===- Linker.cpp - Link together LLVM objects and libraries --------------===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by the LLVM research group and is distributed under
6 // the University of Illinois Open Source License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file contains routines to handle linking together LLVM bytecode files,
11 // and to handle annoying things like static libraries.
13 //===----------------------------------------------------------------------===//
16 #include "llvm/Module.h"
17 #include "llvm/PassManager.h"
18 #include "llvm/Bytecode/Reader.h"
19 #include "llvm/Bytecode/WriteBytecodePass.h"
20 #include "llvm/Target/TargetData.h"
21 #include "llvm/Transforms/IPO.h"
22 #include "llvm/Transforms/Scalar.h"
23 #include "llvm/Transforms/Utils/Linker.h"
24 #include "Support/CommandLine.h"
25 #include "Support/FileUtilities.h"
26 #include "Support/Signals.h"
27 #include "Support/SystemUtils.h"
34 /// FindLib - Try to convert Filename into the name of a file that we can open,
35 /// if it does not already name a file we can open, by first trying to open
36 /// Filename, then libFilename.<suffix> for each of a set of several common
37 /// library suffixes, in each of the directories in Paths and the directory
38 /// named by the value of the environment variable LLVM_LIB_SEARCH_PATH. Returns
39 /// an empty string if no matching file can be found.
41 std::string llvm::FindLib(const std::string &Filename,
42 const std::vector<std::string> &Paths,
43 bool SharedObjectOnly) {
44 // Determine if the pathname can be found as it stands.
45 if (FileOpenable(Filename))
48 // If that doesn't work, convert the name into a library name.
49 std::string LibName = "lib" + Filename;
51 // Iterate over the directories in Paths to see if we can find the library
53 for (unsigned Index = 0; Index != Paths.size(); ++Index) {
54 std::string Directory = Paths[Index] + "/";
56 if (!SharedObjectOnly && FileOpenable(Directory + LibName + ".bc"))
57 return Directory + LibName + ".bc";
59 if (FileOpenable(Directory + LibName + ".so"))
60 return Directory + LibName + ".so";
62 if (!SharedObjectOnly && FileOpenable(Directory + LibName + ".a"))
63 return Directory + LibName + ".a";
66 // One last hope: Check LLVM_LIB_SEARCH_PATH.
67 char *SearchPath = getenv("LLVM_LIB_SEARCH_PATH");
68 if (SearchPath == NULL)
71 LibName = std::string(SearchPath) + "/" + LibName;
72 if (FileOpenable(LibName))
78 /// GetAllDefinedSymbols - Modifies its parameter DefinedSymbols to contain the
79 /// name of each externally-visible symbol defined in M.
81 void llvm::GetAllDefinedSymbols(Module *M,
82 std::set<std::string> &DefinedSymbols) {
83 for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
84 if (I->hasName() && !I->isExternal() && !I->hasInternalLinkage())
85 DefinedSymbols.insert(I->getName());
86 for (Module::giterator I = M->gbegin(), E = M->gend(); I != E; ++I)
87 if (I->hasName() && !I->isExternal() && !I->hasInternalLinkage())
88 DefinedSymbols.insert(I->getName());
91 /// GetAllUndefinedSymbols - calculates the set of undefined symbols that still
92 /// exist in an LLVM module. This is a bit tricky because there may be two
93 /// symbols with the same name but different LLVM types that will be resolved to
94 /// each other but aren't currently (thus we need to treat it as resolved).
97 /// M - The module in which to find undefined symbols.
100 /// UndefinedSymbols - A set of C++ strings containing the name of all
101 /// undefined symbols.
104 llvm::GetAllUndefinedSymbols(Module *M,
105 std::set<std::string> &UndefinedSymbols) {
106 std::set<std::string> DefinedSymbols;
107 UndefinedSymbols.clear(); // Start out empty
109 for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
112 UndefinedSymbols.insert(I->getName());
113 else if (!I->hasInternalLinkage())
114 DefinedSymbols.insert(I->getName());
116 for (Module::giterator I = M->gbegin(), E = M->gend(); I != E; ++I)
119 UndefinedSymbols.insert(I->getName());
120 else if (!I->hasInternalLinkage())
121 DefinedSymbols.insert(I->getName());
124 // Prune out any defined symbols from the undefined symbols set...
125 for (std::set<std::string>::iterator I = UndefinedSymbols.begin();
126 I != UndefinedSymbols.end(); )
127 if (DefinedSymbols.count(*I))
128 UndefinedSymbols.erase(I++); // This symbol really is defined!
130 ++I; // Keep this symbol in the undefined symbols list
134 /// LoadObject - Read in and parse the bytecode file named by FN and return the
135 /// module it contains (wrapped in an auto_ptr), or 0 and set ErrorMessage if an
138 std::auto_ptr<Module> llvm::LoadObject(const std::string &FN,
139 std::string &ErrorMessage) {
140 std::string ParserErrorMessage;
141 Module *Result = ParseBytecodeFile(FN, &ParserErrorMessage);
142 if (Result) return std::auto_ptr<Module>(Result);
143 ErrorMessage = "Bytecode file '" + FN + "' could not be loaded";
144 if (ParserErrorMessage.size()) ErrorMessage += ": " + ParserErrorMessage;
145 return std::auto_ptr<Module>();
148 /// LinkInArchive - opens an archive library and link in all objects which
149 /// provide symbols that are currently undefined.
152 /// M - The module in which to link the archives.
153 /// Filename - The pathname of the archive.
154 /// Verbose - Flags whether verbose messages should be printed.
157 /// ErrorMessage - A C++ string detailing what error occurred, if any.
160 /// TRUE - An error occurred.
161 /// FALSE - No errors.
163 static bool LinkInArchive(Module *M,
164 const std::string &Filename,
165 std::string &ErrorMessage,
168 // Find all of the symbols currently undefined in the bytecode program.
169 // If all the symbols are defined, the program is complete, and there is
170 // no reason to link in any archive files.
171 std::set<std::string> UndefinedSymbols;
172 GetAllUndefinedSymbols(M, UndefinedSymbols);
173 if (UndefinedSymbols.empty()) {
174 if (Verbose) std::cerr << " No symbols undefined, don't link library!\n";
175 return false; // No need to link anything in!
178 // Load in the archive objects.
179 if (Verbose) std::cerr << " Loading archive file '" << Filename << "'\n";
180 std::vector<Module*> Objects;
181 if (ReadArchiveFile(Filename, Objects, &ErrorMessage))
184 // Figure out which symbols are defined by all of the modules in the archive.
185 std::vector<std::set<std::string> > DefinedSymbols;
186 DefinedSymbols.resize(Objects.size());
187 for (unsigned i = 0; i != Objects.size(); ++i) {
188 GetAllDefinedSymbols(Objects[i], DefinedSymbols[i]);
191 // While we are linking in object files, loop.
196 for (unsigned i = 0; i != Objects.size(); ++i) {
197 // Consider whether we need to link in this module... we only need to
198 // link it in if it defines some symbol which is so far undefined.
200 const std::set<std::string> &DefSymbols = DefinedSymbols[i];
202 bool ObjectRequired = false;
203 for (std::set<std::string>::iterator I = UndefinedSymbols.begin(),
204 E = UndefinedSymbols.end(); I != E; ++I)
205 if (DefSymbols.count(*I)) {
207 std::cerr << " Found object '"
208 << Objects[i]->getModuleIdentifier ()
209 << "' providing symbol '" << *I << "'...\n";
210 ObjectRequired = true;
214 // We DO need to link this object into the program...
215 if (ObjectRequired) {
216 if (LinkModules(M, Objects[i], &ErrorMessage))
217 return true; // Couldn't link in the right object file...
219 // Since we have linked in this object, delete it from the list of
220 // objects to consider in this archive file.
221 std::swap(Objects[i], Objects.back());
222 std::swap(DefinedSymbols[i], DefinedSymbols.back());
224 DefinedSymbols.pop_back();
225 --i; // Do not skip an entry
227 // The undefined symbols set should have shrunk.
228 GetAllUndefinedSymbols(M, UndefinedSymbols);
229 Linked = true; // We have linked something in!
237 /// LinkInFile - opens a bytecode file and links in all objects which
238 /// provide symbols that are currently undefined.
241 /// HeadModule - The module in which to link the bytecode file.
242 /// Filename - The pathname of the bytecode file.
243 /// Verbose - Flags whether verbose messages should be printed.
246 /// ErrorMessage - A C++ string detailing what error occurred, if any.
249 /// TRUE - An error occurred.
250 /// FALSE - No errors.
252 static bool LinkInFile(Module *HeadModule,
253 const std::string &Filename,
254 std::string &ErrorMessage,
257 std::auto_ptr<Module> M(LoadObject(Filename, ErrorMessage));
258 if (M.get() == 0) return true;
259 bool Result = LinkModules(HeadModule, M.get(), &ErrorMessage);
260 if (Verbose) std::cerr << "Linked in bytecode file '" << Filename << "'\n";
264 /// LinkFiles - takes a module and a list of files and links them all together.
265 /// It locates the file either in the current directory, as its absolute
266 /// or relative pathname, or as a file somewhere in LLVM_LIB_SEARCH_PATH.
269 /// progname - The name of the program (infamous argv[0]).
270 /// HeadModule - The module under which all files will be linked.
271 /// Files - A vector of C++ strings indicating the LLVM bytecode filenames
272 /// to be linked. The names can refer to a mixture of pure LLVM
273 /// bytecode files and archive (ar) formatted files.
274 /// Verbose - Flags whether verbose output should be printed while linking.
277 /// HeadModule - The module will have the specified LLVM bytecode files linked
281 /// FALSE - No errors.
282 /// TRUE - Some error occurred.
284 bool llvm::LinkFiles(const char *progname, Module *HeadModule,
285 const std::vector<std::string> &Files, bool Verbose) {
286 // String in which to receive error messages.
287 std::string ErrorMessage;
289 // Full pathname of the file
290 std::string Pathname;
292 // Get the library search path from the environment
293 char *SearchPath = getenv("LLVM_LIB_SEARCH_PATH");
295 for (unsigned i = 0; i < Files.size(); ++i) {
296 // Determine where this file lives.
297 if (FileOpenable(Files[i])) {
300 if (SearchPath == NULL) {
301 std::cerr << progname << ": Cannot find linker input file '"
302 << Files[i] << "'\n";
303 std::cerr << progname
304 << ": Warning: Your LLVM_LIB_SEARCH_PATH is unset.\n";
308 Pathname = std::string(SearchPath)+"/"+Files[i];
309 if (!FileOpenable(Pathname)) {
310 std::cerr << progname << ": Cannot find linker input file '"
311 << Files[i] << "'\n";
316 // A user may specify an ar archive without -l, perhaps because it
317 // is not installed as a library. Detect that and link the library.
318 if (IsArchive(Pathname)) {
320 std::cerr << "Trying to link archive '" << Pathname << "'\n";
322 if (LinkInArchive(HeadModule, Pathname, ErrorMessage, Verbose)) {
323 PrintAndReturn(progname, ErrorMessage,
324 ": Error linking in archive '" + Pathname + "'");
327 } else if (IsBytecode(Pathname)) {
329 std::cerr << "Trying to link bytecode file '" << Pathname << "'\n";
331 if (LinkInFile(HeadModule, Pathname, ErrorMessage, Verbose)) {
332 PrintAndReturn(progname, ErrorMessage,
333 ": Error linking in bytecode file '" + Pathname + "'");
342 /// LinkLibraries - takes the specified library files and links them into the
343 /// main bytecode object file.
346 /// progname - The name of the program (infamous argv[0]).
347 /// HeadModule - The module into which all necessary libraries will be linked.
348 /// Libraries - The list of libraries to link into the module.
349 /// LibPaths - The list of library paths in which to find libraries.
350 /// Verbose - Flags whether verbose messages should be printed.
351 /// Native - Flags whether native code is being generated.
354 /// HeadModule - The module will have all necessary libraries linked in.
357 /// FALSE - No error.
360 void llvm::LinkLibraries(const char *progname, Module *HeadModule,
361 const std::vector<std::string> &Libraries,
362 const std::vector<std::string> &LibPaths,
363 bool Verbose, bool Native) {
364 // String in which to receive error messages.
365 std::string ErrorMessage;
367 for (unsigned i = 0; i < Libraries.size(); ++i) {
368 // Determine where this library lives.
369 std::string Pathname = FindLib(Libraries[i], LibPaths);
370 if (Pathname.empty()) {
371 // If the pathname does not exist, then continue to the next one if
372 // we're doing a native link and give an error if we're doing a bytecode
375 std::cerr << progname << ": WARNING: Cannot find library -l"
376 << Libraries[i] << "\n";
381 // A user may specify an ar archive without -l, perhaps because it
382 // is not installed as a library. Detect that and link the library.
383 if (IsArchive(Pathname)) {
385 std::cerr << "Trying to link archive '" << Pathname << "' (-l"
386 << Libraries[i] << ")\n";
388 if (LinkInArchive(HeadModule, Pathname, ErrorMessage, Verbose)) {
389 std::cerr << progname << ": " << ErrorMessage
390 << ": Error linking in archive '" << Pathname << "' (-l"
391 << Libraries[i] << ")\n";
394 } else if (IsBytecode(Pathname)) {
396 std::cerr << "Trying to link bytecode file '" << Pathname
397 << "' (-l" << Libraries[i] << ")\n";
399 if (LinkInFile(HeadModule, Pathname, ErrorMessage, Verbose)) {
400 std::cerr << progname << ": " << ErrorMessage
401 << ": error linking in bytecode file '" << Pathname << "' (-l"
402 << Libraries[i] << ")\n";