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 + SHLIBEXT))
60 return Directory + LibName + SHLIBEXT;
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;
205 // If the object defines main() and the program currently has main()
206 // undefined, then automatically link in the module. Otherwise, look to
207 // see if it defines a symbol that is currently undefined.
209 if ((M->getMainFunction() == NULL) &&
210 ((DefSymbols.find ("main")) != DefSymbols.end())) {
211 ObjectRequired = true;
213 for (std::set<std::string>::iterator I = UndefinedSymbols.begin(),
214 E = UndefinedSymbols.end(); I != E; ++I)
215 if (DefSymbols.count(*I)) {
217 std::cerr << " Found object '"
218 << Objects[i]->getModuleIdentifier ()
219 << "' providing symbol '" << *I << "'...\n";
220 ObjectRequired = true;
225 // We DO need to link this object into the program...
226 if (ObjectRequired) {
227 if (LinkModules(M, Objects[i], &ErrorMessage))
228 return true; // Couldn't link in the right object file...
230 // Since we have linked in this object, delete it from the list of
231 // objects to consider in this archive file.
232 std::swap(Objects[i], Objects.back());
233 std::swap(DefinedSymbols[i], DefinedSymbols.back());
235 DefinedSymbols.pop_back();
236 --i; // Do not skip an entry
238 // The undefined symbols set should have shrunk.
239 GetAllUndefinedSymbols(M, UndefinedSymbols);
240 Linked = true; // We have linked something in!
248 /// LinkInFile - opens a bytecode file and links in all objects which
249 /// provide symbols that are currently undefined.
252 /// HeadModule - The module in which to link the bytecode file.
253 /// Filename - The pathname of the bytecode file.
254 /// Verbose - Flags whether verbose messages should be printed.
257 /// ErrorMessage - A C++ string detailing what error occurred, if any.
260 /// TRUE - An error occurred.
261 /// FALSE - No errors.
263 static bool LinkInFile(Module *HeadModule,
264 const std::string &Filename,
265 std::string &ErrorMessage,
268 std::auto_ptr<Module> M(LoadObject(Filename, ErrorMessage));
269 if (M.get() == 0) return true;
270 bool Result = LinkModules(HeadModule, M.get(), &ErrorMessage);
271 if (Verbose) std::cerr << "Linked in bytecode file '" << Filename << "'\n";
275 /// LinkFiles - takes a module and a list of files and links them all together.
276 /// It locates the file either in the current directory, as its absolute
277 /// or relative pathname, or as a file somewhere in LLVM_LIB_SEARCH_PATH.
280 /// progname - The name of the program (infamous argv[0]).
281 /// HeadModule - The module under which all files will be linked.
282 /// Files - A vector of C++ strings indicating the LLVM bytecode filenames
283 /// to be linked. The names can refer to a mixture of pure LLVM
284 /// bytecode files and archive (ar) formatted files.
285 /// Verbose - Flags whether verbose output should be printed while linking.
288 /// HeadModule - The module will have the specified LLVM bytecode files linked
292 /// FALSE - No errors.
293 /// TRUE - Some error occurred.
295 bool llvm::LinkFiles(const char *progname, Module *HeadModule,
296 const std::vector<std::string> &Files, bool Verbose) {
297 // String in which to receive error messages.
298 std::string ErrorMessage;
300 // Full pathname of the file
301 std::string Pathname;
303 // Get the library search path from the environment
304 char *SearchPath = getenv("LLVM_LIB_SEARCH_PATH");
306 for (unsigned i = 0; i < Files.size(); ++i) {
307 // Determine where this file lives.
308 if (FileOpenable(Files[i])) {
311 if (SearchPath == NULL) {
312 std::cerr << progname << ": Cannot find linker input file '"
313 << Files[i] << "'\n";
314 std::cerr << progname
315 << ": Warning: Your LLVM_LIB_SEARCH_PATH is unset.\n";
319 Pathname = std::string(SearchPath)+"/"+Files[i];
320 if (!FileOpenable(Pathname)) {
321 std::cerr << progname << ": Cannot find linker input file '"
322 << Files[i] << "'\n";
327 // A user may specify an ar archive without -l, perhaps because it
328 // is not installed as a library. Detect that and link the library.
329 if (IsArchive(Pathname)) {
331 std::cerr << "Trying to link archive '" << Pathname << "'\n";
333 if (LinkInArchive(HeadModule, Pathname, ErrorMessage, Verbose)) {
334 PrintAndReturn(progname, ErrorMessage,
335 ": Error linking in archive '" + Pathname + "'");
338 } else if (IsBytecode(Pathname)) {
340 std::cerr << "Trying to link bytecode file '" << Pathname << "'\n";
342 if (LinkInFile(HeadModule, Pathname, ErrorMessage, Verbose)) {
343 PrintAndReturn(progname, ErrorMessage,
344 ": Error linking in bytecode file '" + Pathname + "'");
353 /// LinkLibraries - takes the specified library files and links them into the
354 /// main bytecode object file.
357 /// progname - The name of the program (infamous argv[0]).
358 /// HeadModule - The module into which all necessary libraries will be linked.
359 /// Libraries - The list of libraries to link into the module.
360 /// LibPaths - The list of library paths in which to find libraries.
361 /// Verbose - Flags whether verbose messages should be printed.
362 /// Native - Flags whether native code is being generated.
365 /// HeadModule - The module will have all necessary libraries linked in.
368 /// FALSE - No error.
371 void llvm::LinkLibraries(const char *progname, Module *HeadModule,
372 const std::vector<std::string> &Libraries,
373 const std::vector<std::string> &LibPaths,
374 bool Verbose, bool Native) {
375 // String in which to receive error messages.
376 std::string ErrorMessage;
378 for (unsigned i = 0; i < Libraries.size(); ++i) {
379 // Determine where this library lives.
380 std::string Pathname = FindLib(Libraries[i], LibPaths);
381 if (Pathname.empty()) {
382 // If the pathname does not exist, then continue to the next one if
383 // we're doing a native link and give an error if we're doing a bytecode
386 std::cerr << progname << ": WARNING: Cannot find library -l"
387 << Libraries[i] << "\n";
392 // A user may specify an ar archive without -l, perhaps because it
393 // is not installed as a library. Detect that and link the library.
394 if (IsArchive(Pathname)) {
396 std::cerr << "Trying to link archive '" << Pathname << "' (-l"
397 << Libraries[i] << ")\n";
399 if (LinkInArchive(HeadModule, Pathname, ErrorMessage, Verbose)) {
400 std::cerr << progname << ": " << ErrorMessage
401 << ": Error linking in archive '" << Pathname << "' (-l"
402 << Libraries[i] << ")\n";
405 } else if (IsBytecode(Pathname)) {
407 std::cerr << "Trying to link bytecode file '" << Pathname
408 << "' (-l" << Libraries[i] << ")\n";
410 if (LinkInFile(HeadModule, Pathname, ErrorMessage, Verbose)) {
411 std::cerr << progname << ": " << ErrorMessage
412 << ": error linking in bytecode file '" << Pathname << "' (-l"
413 << Libraries[i] << ")\n";