-//===- Linker.cpp - Link together LLVM objects and libraries --------------===//
+//===- lib/Linker/LinkArchives.cpp - Link 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/Linker.h"
#include "llvm/Module.h"
-#include "llvm/PassManager.h"
+#include "llvm/ModuleProvider.h"
+#include "llvm/ADT/SetOperations.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 "llvm/Bytecode/Archive.h"
+#include "llvm/Config/config.h"
#include <memory>
#include <set>
+using namespace llvm;
-/// FileExists - determines if the specified filename exists and is readable.
-///
-/// Inputs:
-/// FN - The name of the file.
-///
-/// Outputs:
-/// None.
-///
-/// Return Value:
-/// TRUE - The file exists and is readable.
-/// FALSE - The file does not exist or is unreadable.
-///
-static inline bool FileExists(const std::string &FN) {
- return access(FN.c_str(), R_OK | F_OK) != -1;
-}
-
-/// IsArchive - determines if the specified file is an ar archive
-/// by checking the magic string at the beginning of the file.
-///
-/// Inputs:
-/// filename - A C++ string containing the name of the file.
-///
-/// Outputs:
-/// None.
-///
-/// Return value:
-/// TRUE - The file is an archive.
-/// FALSE - The file is not an archive.
-///
-static inline bool IsArchive(const std::string &filename) {
- std::string ArchiveMagic("!<arch>\012");
- char buf[1 + ArchiveMagic.size()];
- std::ifstream f(filename.c_str());
- f.read(buf, ArchiveMagic.size());
- buf[ArchiveMagic.size()] = '\0';
- return ArchiveMagic == buf;
-}
-
-/// FindLib - locates a particular library. It will prepend and append
-/// various directories, prefixes, and suffixes until it can find the library.
-///
-/// Inputs:
-/// Filename - Name of the file to find.
-/// Paths - List of directories to search.
-///
-/// Outputs:
-/// None.
-///
-/// Return value:
-/// The name of the file is returned.
-/// If the file is not found, an empty string is returned.
-///
-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 (FileExists(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 (FileExists(Directory + LibName + ".bc"))
- return Directory + LibName + ".bc";
-
- if (FileExists(Directory + LibName + ".so"))
- return Directory + LibName + ".so";
-
- if (FileExists(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 (FileExists(LibName))
- return LibName;
-
- return std::string();
-}
-
-/// GetAllDefinedSymbols - finds all of the defined symbols in the specified
-/// module.
-///
-/// Inputs:
-/// M - The module in which to find defined symbols.
+/// GetAllDefinedSymbols - Modifies its parameter DefinedSymbols to contain the
+/// name of each externally-visible symbol defined in M.
///
-/// Outputs:
-/// DefinedSymbols - A set of C++ strings that will contain the name of all
-/// defined symbols.
-///
-/// Return value:
-/// None.
-///
-void GetAllDefinedSymbols(Module *M, std::set<std::string> &DefinedSymbols) {
+static 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)
+ for (Module::global_iterator I = M->global_begin(), E = M->global_end();
+ I != E; ++I)
if (I->hasName() && !I->isExternal() && !I->hasInternalLinkage())
DefinedSymbols.insert(I->getName());
}
/// UndefinedSymbols - A set of C++ strings containing the name of all
/// undefined symbols.
///
-/// Return value:
-/// None.
-///
-void
+static void
GetAllUndefinedSymbols(Module *M, std::set<std::string> &UndefinedSymbols) {
std::set<std::string> DefinedSymbols;
- UndefinedSymbols.clear(); // Start out empty
-
+ UndefinedSymbols.clear();
+
+ // If the program doesn't define a main, try pulling one in from a .a file.
+ // This is needed for programs where the main function is defined in an
+ // archive, such f2c'd programs.
+ Function *Main = M->getMainFunction();
+ if (Main == 0 || Main->isExternal())
+ UndefinedSymbols.insert("main");
+
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())
+ else if (!I->hasInternalLinkage()) {
+ assert(!I->hasDLLImportLinkage()
+ && "Found dllimported non-external symbol!");
DefinedSymbols.insert(I->getName());
+ }
}
- for (Module::giterator I = M->gbegin(), E = M->gend(); I != E; ++I)
+ for (Module::global_iterator I = M->global_begin(), E = M->global_end();
+ I != E; ++I)
if (I->hasName()) {
if (I->isExternal())
UndefinedSymbols.insert(I->getName());
- else if (!I->hasInternalLinkage())
+ else if (!I->hasInternalLinkage()) {
+ assert(!I->hasDLLImportLinkage()
+ && "Found dllimported non-external symbol!");
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(); )
++I; // Keep this symbol in the undefined symbols list
}
-
-/// LoadObject - reads the specified bytecode object file.
-///
-/// Inputs:
-/// FN - The name of the file to load.
-///
-/// Outputs:
-/// OutErrorMessage - The error message to give back to the caller.
-///
-/// Return Value:
-/// A pointer to a module represening the bytecode file is returned.
-/// If an error occurs, the pointer is 0.
-///
-std::auto_ptr<Module>
-LoadObject(const std::string & FN, std::string &OutErrorMessage) {
- std::string ErrorMessage;
- Module *Result = ParseBytecodeFile(FN, &ErrorMessage);
- if (Result) return std::auto_ptr<Module>(Result);
- OutErrorMessage = "Bytecode file '" + FN + "' corrupt!";
- if (ErrorMessage.size()) OutErrorMessage += ": " + ErrorMessage;
- 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)
-{
+bool
+Linker::LinkInArchive(const sys::Path &Filename) {
+
+ // Make sure this is an archive file we're dealing with
+ if (!Filename.isArchive())
+ return error("File '" + Filename.toString() + "' is not an archive.");
+
+ // Open the archive file
+ verbose("Linking archive file '" + Filename.toString() + "'");
+
// 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);
+ GetAllUndefinedSymbols(Composite, UndefinedSymbols);
+
if (UndefinedSymbols.empty()) {
- if (Verbose) std::cerr << " No symbols undefined, don't link library!\n";
+ verbose("No symbols undefined, skipping library '" +
+ Filename.toString() + "'");
return false; // No need to link anything in!
}
- // Load in the archive objects.
- if (Verbose) std::cerr << " Loading '" << Filename << "'\n";
- std::vector<Module*> Objects;
- if (ReadArchiveFile(Filename, Objects, &ErrorMessage))
- return true;
+ std::string ErrMsg;
+ std::auto_ptr<Archive> AutoArch (
+ Archive::OpenAndLoadSymbols(Filename,&ErrMsg));
- // 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]);
- }
+ Archive* arch = AutoArch.get();
- // While we are linking in object files, loop.
- bool Linked = true;
- while (Linked) {
- Linked = false;
+ if (!arch)
+ return error("Cannot read archive '" + Filename.toString() +
+ "': " + ErrMsg);
- 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];
+ // Save a set of symbols that are not defined by the archive. Since we're
+ // entering a loop, there's no point searching for these multiple times. This
+ // variable is used to "set_subtract" from the set of undefined symbols.
+ std::set<std::string> NotDefinedByArchive;
- 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 an archive library and link in all objects which
-/// provide symbols that are currently undefined.
-///
-/// Inputs:
-/// HeadModule - 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 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;
- if (Verbose) std::cerr << "Linking in '" << Filename << "'\n";
- return LinkModules(HeadModule, M.get(), &ErrorMessage);
-}
-
-/// 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 = 1; i < Files.size(); ++i) {
- // Determine where this file lives.
- if (FileExists(Files[i])) {
- Pathname = Files[i];
- } else {
- if (SearchPath == NULL) {
- std::cerr << progname << ": Cannot find linker input file '"
- << Files[i] << "'\n";
- return true;
- }
-
- Pathname = std::string(SearchPath)+"/"+Files[i];
- if (!FileExists(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 << "Linking archive '" << Files[i] << "'\n";
-
- if (LinkInArchive(HeadModule, Pathname, ErrorMessage, Verbose)) {
- PrintAndReturn(progname, ErrorMessage,
- ": Error linking in '" + Files[i] + "'");
- return true;
- }
- } else {
- if (Verbose)
- std::cerr << "Linking file '" << Files[i] << "'\n";
-
- if (LinkInFile(HeadModule, Pathname, ErrorMessage, Verbose)) {
- PrintAndReturn(progname, ErrorMessage,
- ": Error linking in '" + Files[i] + "'");
- 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 = 1; 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 " + Libraries[i] + "\n");
- return true;
- }
+ // While we are linking in object files, loop.
+ while (true) {
+
+ // Find the modules we need to link into the target module
+ std::set<ModuleProvider*> Modules;
+ if (!arch->findModulesDefiningSymbols(UndefinedSymbols, Modules, &ErrMsg))
+ return error("Cannot find symbols in '" + Filename.toString() +
+ "': " + ErrMsg);
+
+ // If we didn't find any more modules to link this time, we are done
+ // searching this archive.
+ if (Modules.empty())
+ break;
+
+ // Any symbols remaining in UndefinedSymbols after
+ // findModulesDefiningSymbols are ones that the archive does not define. So
+ // we add them to the NotDefinedByArchive variable now.
+ NotDefinedByArchive.insert(UndefinedSymbols.begin(),
+ UndefinedSymbols.end());
+
+ // Loop over all the ModuleProviders that we got back from the archive
+ for (std::set<ModuleProvider*>::iterator I=Modules.begin(), E=Modules.end();
+ I != E; ++I) {
+
+ // Get the module we must link in.
+ std::auto_ptr<Module> AutoModule( (*I)->releaseModule() );
+ Module* aModule = AutoModule.get();
+
+ verbose(" Linking in module: " + aModule->getModuleIdentifier());
+
+ // Link it in
+ if (LinkInModule(aModule))
+ return error("Cannot link in module '" +
+ aModule->getModuleIdentifier() + "': " + Error);
}
- // 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 << "Linking archive '" << Libraries[i] << "'\n";
-
- if (LinkInArchive(HeadModule, Pathname, ErrorMessage, Verbose)) {
- PrintAndReturn(progname, ErrorMessage,
- ": Error linking in '" + Libraries[i] + "'");
- return true;
- }
- } else {
- if (Verbose)
- std::cerr << "Linking file '" << Libraries[i] << "'\n";
-
- if (LinkInFile(HeadModule, Pathname, ErrorMessage, Verbose)) {
- PrintAndReturn(progname, ErrorMessage,
- ": error linking in '" + Libraries[i] + "'");
- return true;
- }
- }
+ // Get the undefined symbols from the aggregate module. This recomputes the
+ // symbols we still need after the new modules have been linked in.
+ GetAllUndefinedSymbols(Composite, UndefinedSymbols);
+
+ // At this point we have two sets of undefined symbols: UndefinedSymbols
+ // which holds the undefined symbols from all the modules, and
+ // NotDefinedByArchive which holds symbols we know the archive doesn't
+ // define. There's no point searching for symbols that we won't find in the
+ // archive so we subtract these sets.
+ set_subtract(UndefinedSymbols, NotDefinedByArchive);
+
+ // If there's no symbols left, no point in continuing to search the
+ // archive.
+ if (UndefinedSymbols.empty())
+ break;
}
return false;
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