1 //===- lib/Linker/LinkArchives.cpp - Link 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 //===----------------------------------------------------------------------===//
15 #include "llvm/Linker.h"
16 #include "llvm/Module.h"
17 #include "llvm/ModuleProvider.h"
18 #include "llvm/PassManager.h"
19 #include "llvm/Bytecode/Reader.h"
20 #include "llvm/Bytecode/Archive.h"
21 #include "llvm/Bytecode/WriteBytecodePass.h"
22 #include "llvm/Target/TargetData.h"
23 #include "llvm/Transforms/IPO.h"
24 #include "llvm/Transforms/Scalar.h"
25 #include "llvm/Config/config.h"
26 #include "llvm/Support/CommandLine.h"
27 #include "llvm/Support/FileUtilities.h"
28 #include "llvm/System/Signals.h"
29 #include "llvm/Support/SystemUtils.h"
36 /// FindLib - Try to convert Filename into the name of a file that we can open,
37 /// if it does not already name a file we can open, by first trying to open
38 /// Filename, then libFilename.[suffix] for each of a set of several common
39 /// library suffixes, in each of the directories in Paths and the directory
40 /// named by the value of the environment variable LLVM_LIB_SEARCH_PATH. Returns
41 /// an empty string if no matching file can be found.
43 std::string llvm::FindLib(const std::string &Filename,
44 const std::vector<std::string> &Paths,
45 bool SharedObjectOnly) {
46 // Determine if the pathname can be found as it stands.
47 if (FileOpenable(Filename))
50 // If that doesn't work, convert the name into a library name.
51 std::string LibName = "lib" + Filename;
53 // Iterate over the directories in Paths to see if we can find the library
55 for (unsigned Index = 0; Index != Paths.size(); ++Index) {
56 std::string Directory = Paths[Index] + "/";
58 if (!SharedObjectOnly && FileOpenable(Directory + LibName + ".bc"))
59 return Directory + LibName + ".bc";
61 if (FileOpenable(Directory + LibName + SHLIBEXT))
62 return Directory + LibName + SHLIBEXT;
64 if (!SharedObjectOnly && FileOpenable(Directory + LibName + ".a"))
65 return Directory + LibName + ".a";
68 // One last hope: Check LLVM_LIB_SEARCH_PATH.
69 char *SearchPath = getenv("LLVM_LIB_SEARCH_PATH");
70 if (SearchPath == NULL)
73 LibName = std::string(SearchPath) + "/" + LibName;
74 if (FileOpenable(LibName))
80 /// GetAllDefinedSymbols - Modifies its parameter DefinedSymbols to contain the
81 /// name of each externally-visible symbol defined in M.
83 void llvm::GetAllDefinedSymbols(Module *M,
84 std::set<std::string> &DefinedSymbols) {
85 for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
86 if (I->hasName() && !I->isExternal() && !I->hasInternalLinkage())
87 DefinedSymbols.insert(I->getName());
88 for (Module::giterator I = M->gbegin(), E = M->gend(); I != E; ++I)
89 if (I->hasName() && !I->isExternal() && !I->hasInternalLinkage())
90 DefinedSymbols.insert(I->getName());
93 /// GetAllUndefinedSymbols - calculates the set of undefined symbols that still
94 /// exist in an LLVM module. This is a bit tricky because there may be two
95 /// symbols with the same name but different LLVM types that will be resolved to
96 /// each other but aren't currently (thus we need to treat it as resolved).
99 /// M - The module in which to find undefined symbols.
102 /// UndefinedSymbols - A set of C++ strings containing the name of all
103 /// undefined symbols.
106 llvm::GetAllUndefinedSymbols(Module *M,
107 std::set<std::string> &UndefinedSymbols) {
108 std::set<std::string> DefinedSymbols;
109 UndefinedSymbols.clear(); // Start out empty
111 for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
114 UndefinedSymbols.insert(I->getName());
115 else if (!I->hasInternalLinkage())
116 DefinedSymbols.insert(I->getName());
118 for (Module::giterator I = M->gbegin(), E = M->gend(); I != E; ++I)
121 UndefinedSymbols.insert(I->getName());
122 else if (!I->hasInternalLinkage())
123 DefinedSymbols.insert(I->getName());
126 // Prune out any defined symbols from the undefined symbols set...
127 for (std::set<std::string>::iterator I = UndefinedSymbols.begin();
128 I != UndefinedSymbols.end(); )
129 if (DefinedSymbols.count(*I))
130 UndefinedSymbols.erase(I++); // This symbol really is defined!
132 ++I; // Keep this symbol in the undefined symbols list
136 /// LoadObject - Read in and parse the bytecode file named by FN and return the
137 /// module it contains (wrapped in an auto_ptr), or 0 and set ErrorMessage if an
140 static std::auto_ptr<Module> LoadObject(const std::string &FN,
141 std::string &ErrorMessage) {
142 std::string ParserErrorMessage;
143 Module *Result = ParseBytecodeFile(FN, &ParserErrorMessage);
144 if (Result) return std::auto_ptr<Module>(Result);
145 ErrorMessage = "Bytecode file '" + FN + "' could not be loaded";
146 if (ParserErrorMessage.size()) ErrorMessage += ": " + ParserErrorMessage;
147 return std::auto_ptr<Module>();
150 /// LinkInArchive - opens an archive library and link in all objects which
151 /// provide symbols that are currently undefined.
154 /// M - The module in which to link the archives.
155 /// Filename - The pathname of the archive.
156 /// Verbose - Flags whether verbose messages should be printed.
159 /// ErrorMessage - A C++ string detailing what error occurred, if any.
162 /// TRUE - An error occurred.
163 /// FALSE - No errors.
165 bool llvm::LinkInArchive(Module *M,
166 const std::string &Filename,
167 std::string* ErrorMessage,
170 // Find all of the symbols currently undefined in the bytecode program.
171 // If all the symbols are defined, the program is complete, and there is
172 // no reason to link in any archive files.
173 std::set<std::string> UndefinedSymbols;
174 GetAllUndefinedSymbols(M, UndefinedSymbols);
175 if (UndefinedSymbols.empty()) {
176 if (Verbose) std::cerr << " No symbols undefined, don't link library!\n";
177 return false; // No need to link anything in!
180 // Open the archive file
181 if (Verbose) std::cerr << " Loading archive file '" << Filename << "'\n";
182 Archive* arch = Archive::OpenAndLoadSymbols(sys::Path(Filename));
184 // While we are linking in object files, loop.
186 std::set<ModuleProvider*> Modules;
187 // Find the modules we need to link
188 arch->findModulesDefiningSymbols(UndefinedSymbols,Modules);
190 // If we didn't find any more modules to link this time, we are done.
194 // Loop over all the ModuleProviders that we got back from the archive
195 for (std::set<ModuleProvider*>::iterator I=Modules.begin(), E=Modules.end();
197 // Get the module we must link in.
198 Module* aModule = (*I)->releaseModule();
201 if (LinkModules(M, aModule, ErrorMessage)) {
202 // don't create a memory leak
205 return true; // Couldn't link in the right object file...
208 // Since we have linked in this object, throw it away now.
212 // We have linked in a set of modules determined by the archive to satisfy
213 // our missing symbols. Linking in the new modules will have satisfied some
214 // symbols but may introduce additional missing symbols. We need to update
215 // the list of undefined symbols and try again until the archive doesn't
216 // have any modules that satisfy our symbols.
217 GetAllUndefinedSymbols(M, UndefinedSymbols);
223 /// LinkInFile - opens a bytecode file and links in all objects which
224 /// provide symbols that are currently undefined.
227 /// HeadModule - The module in which to link the bytecode file.
228 /// Filename - The pathname of the bytecode file.
229 /// Verbose - Flags whether verbose messages should be printed.
232 /// ErrorMessage - A C++ string detailing what error occurred, if any.
235 /// TRUE - An error occurred.
236 /// FALSE - No errors.
238 static bool LinkInFile(Module *HeadModule,
239 const std::string &Filename,
240 std::string &ErrorMessage,
243 std::auto_ptr<Module> M(LoadObject(Filename, ErrorMessage));
244 if (M.get() == 0) return true;
245 bool Result = LinkModules(HeadModule, M.get(), &ErrorMessage);
246 if (Verbose) std::cerr << "Linked in bytecode file '" << Filename << "'\n";
250 /// LinkFiles - takes a module and a list of files and links them all together.
251 /// It locates the file either in the current directory, as its absolute
252 /// or relative pathname, or as a file somewhere in LLVM_LIB_SEARCH_PATH.
255 /// progname - The name of the program (infamous argv[0]).
256 /// HeadModule - The module under which all files will be linked.
257 /// Files - A vector of C++ strings indicating the LLVM bytecode filenames
258 /// to be linked. The names can refer to a mixture of pure LLVM
259 /// bytecode files and archive (ar) formatted files.
260 /// Verbose - Flags whether verbose output should be printed while linking.
263 /// HeadModule - The module will have the specified LLVM bytecode files linked
267 /// FALSE - No errors.
268 /// TRUE - Some error occurred.
270 bool llvm::LinkFiles(const char *progname, Module *HeadModule,
271 const std::vector<std::string> &Files, bool Verbose) {
272 // String in which to receive error messages.
273 std::string ErrorMessage;
275 // Full pathname of the file
276 std::string Pathname;
278 // Get the library search path from the environment
279 char *SearchPath = getenv("LLVM_LIB_SEARCH_PATH");
281 for (unsigned i = 0; i < Files.size(); ++i) {
282 // Determine where this file lives.
283 if (FileOpenable(Files[i])) {
286 if (SearchPath == NULL) {
287 std::cerr << progname << ": Cannot find linker input file '"
288 << Files[i] << "'\n";
289 std::cerr << progname
290 << ": Warning: Your LLVM_LIB_SEARCH_PATH is unset.\n";
294 Pathname = std::string(SearchPath)+"/"+Files[i];
295 if (!FileOpenable(Pathname)) {
296 std::cerr << progname << ": Cannot find linker input file '"
297 << Files[i] << "'\n";
302 // A user may specify an ar archive without -l, perhaps because it
303 // is not installed as a library. Detect that and link the library.
304 if (IsArchive(Pathname)) {
306 std::cerr << "Trying to link archive '" << Pathname << "'\n";
308 if (LinkInArchive(HeadModule, Pathname, &ErrorMessage, Verbose)) {
309 std::cerr << progname << ": Error linking in archive '" << Pathname
310 << "': " << ErrorMessage << "\n";
313 } else if (IsBytecode(Pathname)) {
315 std::cerr << "Trying to link bytecode file '" << Pathname << "'\n";
317 if (LinkInFile(HeadModule, Pathname, ErrorMessage, Verbose)) {
318 std::cerr << progname << ": Error linking in bytecode file '"
319 << Pathname << "': " << ErrorMessage << "\n";
323 std::cerr << progname << ": Warning: invalid file `" << Pathname
331 /// LinkLibraries - takes the specified library files and links them into the
332 /// main bytecode object file.
335 /// progname - The name of the program (infamous argv[0]).
336 /// HeadModule - The module into which all necessary libraries will be linked.
337 /// Libraries - The list of libraries to link into the module.
338 /// LibPaths - The list of library paths in which to find libraries.
339 /// Verbose - Flags whether verbose messages should be printed.
340 /// Native - Flags whether native code is being generated.
343 /// HeadModule - The module will have all necessary libraries linked in.
346 /// FALSE - No error.
349 void llvm::LinkLibraries(const char *progname, Module *HeadModule,
350 const std::vector<std::string> &Libraries,
351 const std::vector<std::string> &LibPaths,
352 bool Verbose, bool Native) {
353 // String in which to receive error messages.
354 std::string ErrorMessage;
356 for (unsigned i = 0; i < Libraries.size(); ++i) {
357 // Determine where this library lives.
358 std::string Pathname = FindLib(Libraries[i], LibPaths);
359 if (Pathname.empty()) {
360 // If the pathname does not exist, then continue to the next one if
361 // we're doing a native link and give an error if we're doing a bytecode
364 std::cerr << progname << ": WARNING: Cannot find library -l"
365 << Libraries[i] << "\n";
370 // A user may specify an ar archive without -l, perhaps because it
371 // is not installed as a library. Detect that and link the library.
372 if (IsArchive(Pathname)) {
374 std::cerr << "Trying to link archive '" << Pathname << "' (-l"
375 << Libraries[i] << ")\n";
377 if (LinkInArchive(HeadModule, Pathname, &ErrorMessage, Verbose)) {
378 std::cerr << progname << ": " << ErrorMessage
379 << ": Error linking in archive '" << Pathname << "' (-l"
380 << Libraries[i] << ")\n";
383 } else if (IsBytecode(Pathname)) {
385 std::cerr << "Trying to link bytecode file '" << Pathname
386 << "' (-l" << Libraries[i] << ")\n";
388 if (LinkInFile(HeadModule, Pathname, ErrorMessage, Verbose)) {
389 std::cerr << progname << ": " << ErrorMessage
390 << ": error linking in bytecode file '" << Pathname << "' (-l"
391 << Libraries[i] << ")\n";