| //===- Linker.cpp - Link together LLVM objects and libraries --------------===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file was developed by the LLVM research group and is distributed under |
| // the University of Illinois Open Source License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file contains routines to handle linking together LLVM bytecode files, |
| // and to handle annoying things like static libraries. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "gccld.h" |
| #include "llvm/Module.h" |
| #include "llvm/PassManager.h" |
| #include "llvm/Bytecode/Reader.h" |
| #include "llvm/Bytecode/WriteBytecodePass.h" |
| #include "llvm/Target/TargetData.h" |
| #include "llvm/Transforms/IPO.h" |
| #include "llvm/Transforms/Scalar.h" |
| #include "llvm/Transforms/Utils/Linker.h" |
| #include "Support/CommandLine.h" |
| #include "Support/FileUtilities.h" |
| #include "Support/Signals.h" |
| #include "Support/SystemUtils.h" |
| #include <algorithm> |
| #include <fstream> |
| #include <memory> |
| #include <set> |
| |
| namespace llvm { |
| |
| /// FindLib - Try to convert Filename into the name of a file that we can open, |
| /// if it does not already name a file we can open, by first trying to open |
| /// Filename, then libFilename.<suffix> for each of a set of several common |
| /// library suffixes, in each of the directories in Paths and the directory |
| /// named by the value of the environment variable LLVM_LIB_SEARCH_PATH. Returns |
| /// an empty string if no matching file can be found. |
| /// |
| static std::string FindLib(const std::string &Filename, |
| const std::vector<std::string> &Paths) { |
| // Determine if the pathname can be found as it stands. |
| if (FileOpenable(Filename)) |
| return Filename; |
| |
| // If that doesn't work, convert the name into a library name. |
| std::string LibName = "lib" + Filename; |
| |
| // Iterate over the directories in Paths to see if we can find the library |
| // there. |
| for (unsigned Index = 0; Index != Paths.size(); ++Index) { |
| std::string Directory = Paths[Index] + "/"; |
| |
| if (FileOpenable(Directory + LibName + ".bc")) |
| return Directory + LibName + ".bc"; |
| |
| if (FileOpenable(Directory + LibName + ".so")) |
| return Directory + LibName + ".so"; |
| |
| if (FileOpenable(Directory + LibName + ".a")) |
| return Directory + LibName + ".a"; |
| } |
| |
| // One last hope: Check LLVM_LIB_SEARCH_PATH. |
| char *SearchPath = getenv("LLVM_LIB_SEARCH_PATH"); |
| if (SearchPath == NULL) |
| return std::string(); |
| |
| LibName = std::string(SearchPath) + "/" + LibName; |
| if (FileOpenable(LibName)) |
| return LibName; |
| |
| return std::string(); |
| } |
| |
| /// GetAllDefinedSymbols - Modifies its parameter DefinedSymbols to contain the |
| /// name of each externally-visible symbol defined in M. |
| /// |
| void GetAllDefinedSymbols(Module *M, std::set<std::string> &DefinedSymbols) { |
| for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I) |
| if (I->hasName() && !I->isExternal() && !I->hasInternalLinkage()) |
| DefinedSymbols.insert(I->getName()); |
| for (Module::giterator I = M->gbegin(), E = M->gend(); I != E; ++I) |
| if (I->hasName() && !I->isExternal() && !I->hasInternalLinkage()) |
| DefinedSymbols.insert(I->getName()); |
| } |
| |
| /// GetAllUndefinedSymbols - calculates the set of undefined symbols that still |
| /// exist in an LLVM module. This is a bit tricky because there may be two |
| /// symbols with the same name but different LLVM types that will be resolved to |
| /// each other but aren't currently (thus we need to treat it as resolved). |
| /// |
| /// Inputs: |
| /// M - The module in which to find undefined symbols. |
| /// |
| /// Outputs: |
| /// UndefinedSymbols - A set of C++ strings containing the name of all |
| /// undefined symbols. |
| /// |
| /// Return value: |
| /// None. |
| /// |
| void |
| GetAllUndefinedSymbols(Module *M, std::set<std::string> &UndefinedSymbols) { |
| std::set<std::string> DefinedSymbols; |
| UndefinedSymbols.clear(); // Start out empty |
| |
| for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I) |
| if (I->hasName()) { |
| if (I->isExternal()) |
| UndefinedSymbols.insert(I->getName()); |
| else if (!I->hasInternalLinkage()) |
| DefinedSymbols.insert(I->getName()); |
| } |
| for (Module::giterator I = M->gbegin(), E = M->gend(); I != E; ++I) |
| if (I->hasName()) { |
| if (I->isExternal()) |
| UndefinedSymbols.insert(I->getName()); |
| else if (!I->hasInternalLinkage()) |
| DefinedSymbols.insert(I->getName()); |
| } |
| |
| // Prune out any defined symbols from the undefined symbols set... |
| for (std::set<std::string>::iterator I = UndefinedSymbols.begin(); |
| I != UndefinedSymbols.end(); ) |
| if (DefinedSymbols.count(*I)) |
| UndefinedSymbols.erase(I++); // This symbol really is defined! |
| else |
| ++I; // Keep this symbol in the undefined symbols list |
| } |
| |
| |
| /// LoadObject - Read in and parse the bytecode file named by FN and return the |
| /// module it contains (wrapped in an auto_ptr), or 0 and set ErrorMessage if an |
| /// error occurs. |
| /// |
| std::auto_ptr<Module> LoadObject(const std::string &FN, |
| std::string &ErrorMessage) { |
| std::string ParserErrorMessage; |
| Module *Result = ParseBytecodeFile(FN, &ParserErrorMessage); |
| if (Result) return std::auto_ptr<Module>(Result); |
| ErrorMessage = "Bytecode file '" + FN + "' could not be loaded"; |
| if (ParserErrorMessage.size()) ErrorMessage += ": " + ParserErrorMessage; |
| return std::auto_ptr<Module>(); |
| } |
| |
| /// LinkInArchive - opens an archive library and link in all objects which |
| /// provide symbols that are currently undefined. |
| /// |
| /// Inputs: |
| /// M - The module in which to link the archives. |
| /// Filename - The pathname of the archive. |
| /// Verbose - Flags whether verbose messages should be printed. |
| /// |
| /// Outputs: |
| /// ErrorMessage - A C++ string detailing what error occurred, if any. |
| /// |
| /// Return Value: |
| /// TRUE - An error occurred. |
| /// FALSE - No errors. |
| /// |
| static bool LinkInArchive(Module *M, |
| const std::string &Filename, |
| std::string &ErrorMessage, |
| bool Verbose) |
| { |
| // Find all of the symbols currently undefined in the bytecode program. |
| // If all the symbols are defined, the program is complete, and there is |
| // no reason to link in any archive files. |
| std::set<std::string> UndefinedSymbols; |
| GetAllUndefinedSymbols(M, UndefinedSymbols); |
| if (UndefinedSymbols.empty()) { |
| if (Verbose) std::cerr << " No symbols undefined, don't link library!\n"; |
| return false; // No need to link anything in! |
| } |
| |
| // Load in the archive objects. |
| if (Verbose) std::cerr << " Loading archive file '" << Filename << "'\n"; |
| std::vector<Module*> Objects; |
| if (ReadArchiveFile(Filename, Objects, &ErrorMessage)) |
| return true; |
| |
| // Figure out which symbols are defined by all of the modules in the archive. |
| std::vector<std::set<std::string> > DefinedSymbols; |
| DefinedSymbols.resize(Objects.size()); |
| for (unsigned i = 0; i != Objects.size(); ++i) { |
| GetAllDefinedSymbols(Objects[i], DefinedSymbols[i]); |
| } |
| |
| // While we are linking in object files, loop. |
| bool Linked = true; |
| while (Linked) { |
| Linked = false; |
| |
| for (unsigned i = 0; i != Objects.size(); ++i) { |
| // Consider whether we need to link in this module... we only need to |
| // link it in if it defines some symbol which is so far undefined. |
| // |
| const std::set<std::string> &DefSymbols = DefinedSymbols[i]; |
| |
| bool ObjectRequired = false; |
| for (std::set<std::string>::iterator I = UndefinedSymbols.begin(), |
| E = UndefinedSymbols.end(); I != E; ++I) |
| if (DefSymbols.count(*I)) { |
| if (Verbose) |
| std::cerr << " Found object providing symbol '" << *I << "'...\n"; |
| ObjectRequired = true; |
| break; |
| } |
| |
| // We DO need to link this object into the program... |
| if (ObjectRequired) { |
| if (LinkModules(M, Objects[i], &ErrorMessage)) |
| return true; // Couldn't link in the right object file... |
| |
| // Since we have linked in this object, delete it from the list of |
| // objects to consider in this archive file. |
| std::swap(Objects[i], Objects.back()); |
| std::swap(DefinedSymbols[i], DefinedSymbols.back()); |
| Objects.pop_back(); |
| DefinedSymbols.pop_back(); |
| --i; // Do not skip an entry |
| |
| // The undefined symbols set should have shrunk. |
| GetAllUndefinedSymbols(M, UndefinedSymbols); |
| Linked = true; // We have linked something in! |
| } |
| } |
| } |
| |
| return false; |
| } |
| |
| /// LinkInFile - opens a bytecode file and links in all objects which |
| /// provide symbols that are currently undefined. |
| /// |
| /// Inputs: |
| /// HeadModule - The module in which to link the bytecode file. |
| /// Filename - The pathname of the bytecode file. |
| /// Verbose - Flags whether verbose messages should be printed. |
| /// |
| /// Outputs: |
| /// ErrorMessage - A C++ string detailing what error occurred, if any. |
| /// |
| /// Return Value: |
| /// TRUE - An error occurred. |
| /// FALSE - No errors. |
| /// |
| static bool LinkInFile(Module *HeadModule, |
| const std::string &Filename, |
| std::string &ErrorMessage, |
| bool Verbose) |
| { |
| std::auto_ptr<Module> M(LoadObject(Filename, ErrorMessage)); |
| if (M.get() == 0) return true; |
| bool Result = LinkModules(HeadModule, M.get(), &ErrorMessage); |
| if (Verbose) std::cerr << "Linked in bytecode file '" << Filename << "'\n"; |
| return Result; |
| } |
| |
| /// LinkFiles - takes a module and a list of files and links them all together. |
| /// It locates the file either in the current directory, as its absolute |
| /// or relative pathname, or as a file somewhere in LLVM_LIB_SEARCH_PATH. |
| /// |
| /// Inputs: |
| /// progname - The name of the program (infamous argv[0]). |
| /// HeadModule - The module under which all files will be linked. |
| /// Files - A vector of C++ strings indicating the LLVM bytecode filenames |
| /// to be linked. The names can refer to a mixture of pure LLVM |
| /// bytecode files and archive (ar) formatted files. |
| /// Verbose - Flags whether verbose output should be printed while linking. |
| /// |
| /// Outputs: |
| /// HeadModule - The module will have the specified LLVM bytecode files linked |
| /// in. |
| /// |
| /// Return value: |
| /// FALSE - No errors. |
| /// TRUE - Some error occurred. |
| /// |
| bool LinkFiles(const char *progname, |
| Module *HeadModule, |
| const std::vector<std::string> &Files, |
| bool Verbose) |
| { |
| // String in which to receive error messages. |
| std::string ErrorMessage; |
| |
| // Full pathname of the file |
| std::string Pathname; |
| |
| // Get the library search path from the environment |
| char *SearchPath = getenv("LLVM_LIB_SEARCH_PATH"); |
| |
| for (unsigned i = 0; i < Files.size(); ++i) { |
| // Determine where this file lives. |
| if (FileOpenable(Files[i])) { |
| Pathname = Files[i]; |
| } else { |
| if (SearchPath == NULL) { |
| std::cerr << progname << ": Cannot find linker input file '" |
| << Files[i] << "'\n"; |
| std::cerr << progname |
| << ": Warning: Your LLVM_LIB_SEARCH_PATH is unset.\n"; |
| return true; |
| } |
| |
| Pathname = std::string(SearchPath)+"/"+Files[i]; |
| if (!FileOpenable(Pathname)) { |
| std::cerr << progname << ": Cannot find linker input file '" |
| << Files[i] << "'\n"; |
| return true; |
| } |
| } |
| |
| // A user may specify an ar archive without -l, perhaps because it |
| // is not installed as a library. Detect that and link the library. |
| if (IsArchive(Pathname)) { |
| if (Verbose) |
| std::cerr << "Trying to link archive '" << Pathname << "'\n"; |
| |
| if (LinkInArchive(HeadModule, Pathname, ErrorMessage, Verbose)) { |
| PrintAndReturn(progname, ErrorMessage, |
| ": Error linking in archive '" + Pathname + "'"); |
| return true; |
| } |
| } else if (IsBytecode(Pathname)) { |
| if (Verbose) |
| std::cerr << "Trying to link bytecode file '" << Pathname << "'\n"; |
| |
| if (LinkInFile(HeadModule, Pathname, ErrorMessage, Verbose)) { |
| PrintAndReturn(progname, ErrorMessage, |
| ": Error linking in bytecode file '" + Pathname + "'"); |
| return true; |
| } |
| } |
| } |
| |
| return false; |
| } |
| |
| /// LinkLibraries - takes the specified library files and links them into the |
| /// main bytecode object file. |
| /// |
| /// Inputs: |
| /// progname - The name of the program (infamous argv[0]). |
| /// HeadModule - The module into which all necessary libraries will be linked. |
| /// Libraries - The list of libraries to link into the module. |
| /// LibPaths - The list of library paths in which to find libraries. |
| /// Verbose - Flags whether verbose messages should be printed. |
| /// Native - Flags whether native code is being generated. |
| /// |
| /// Outputs: |
| /// HeadModule - The module will have all necessary libraries linked in. |
| /// |
| /// Return value: |
| /// FALSE - No error. |
| /// TRUE - Error. |
| /// |
| bool LinkLibraries(const char *progname, |
| Module *HeadModule, |
| const std::vector<std::string> &Libraries, |
| const std::vector<std::string> &LibPaths, |
| bool Verbose, |
| bool Native) |
| { |
| // String in which to receive error messages. |
| std::string ErrorMessage; |
| |
| for (unsigned i = 0; i < Libraries.size(); ++i) { |
| // Determine where this library lives. |
| std::string Pathname = FindLib(Libraries[i], LibPaths); |
| if (Pathname.empty()) { |
| // If the pathname does not exist, then continue to the next one if |
| // we're doing a native link and give an error if we're doing a bytecode |
| // link. |
| if (!Native) { |
| PrintAndReturn(progname, "Cannot find library -l" + Libraries[i] + "\n"); |
| return true; |
| } |
| } |
| |
| // A user may specify an ar archive without -l, perhaps because it |
| // is not installed as a library. Detect that and link the library. |
| if (IsArchive(Pathname)) { |
| if (Verbose) |
| std::cerr << "Trying to link archive '" << Pathname << "' (-l" << Libraries[i] << ")\n"; |
| |
| if (LinkInArchive(HeadModule, Pathname, ErrorMessage, Verbose)) { |
| PrintAndReturn(progname, ErrorMessage, |
| ": Error linking in archive '" + Pathname + "' (-l" + Libraries[i] + ")"); |
| return true; |
| } |
| } else if (IsBytecode(Pathname)) { |
| if (Verbose) |
| std::cerr << "Trying to link bytecode file '" << Pathname << "' (-l" << Libraries[i] << ")\n"; |
| |
| if (LinkInFile(HeadModule, Pathname, ErrorMessage, Verbose)) { |
| PrintAndReturn(progname, ErrorMessage, |
| ": error linking in bytecode file '" + Pathname + "' (-l" + Libraries[i] + ")"); |
| return true; |
| } |
| } |
| } |
| |
| return false; |
| } |
| |
| } // End llvm namespace |