Initial implementation of llvm-ld: stolen from gccld.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@16305 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/tools/llvm-ld/Linker.cpp b/tools/llvm-ld/Linker.cpp
new file mode 100644
index 0000000..42788f2
--- /dev/null
+++ b/tools/llvm-ld/Linker.cpp
@@ -0,0 +1,419 @@
+//===- 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 "llvm-ld.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/Support/Linker.h"
+#include "llvm/Config/config.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/FileUtilities.h"
+#include "llvm/System/Signals.h"
+#include "llvm/Support/SystemUtils.h"
+#include <algorithm>
+#include <fstream>
+#include <memory>
+#include <set>
+using 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.
+///
+std::string llvm::FindLib(const std::string &Filename,
+ const std::vector<std::string> &Paths,
+ bool SharedObjectOnly) {
+ // 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 (!SharedObjectOnly && FileOpenable(Directory + LibName + ".bc"))
+ return Directory + LibName + ".bc";
+
+ if (FileOpenable(Directory + LibName + SHLIBEXT))
+ return Directory + LibName + SHLIBEXT;
+
+ if (!SharedObjectOnly && 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 llvm::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.
+///
+void
+llvm::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> llvm::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;
+
+ //
+ // If the object defines main() and the program currently has main()
+ // undefined, then automatically link in the module. Otherwise, look to
+ // see if it defines a symbol that is currently undefined.
+ //
+ if ((M->getMainFunction() == NULL) &&
+ ((DefSymbols.find ("main")) != DefSymbols.end())) {
+ ObjectRequired = true;
+ } else {
+ 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 '"
+ << Objects[i]->getModuleIdentifier ()
+ << "' 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 llvm::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)) {
+ std::cerr << progname << ": Error linking in archive '" << Pathname
+ << "': " << ErrorMessage << "\n";
+ return true;
+ }
+ } else if (IsBytecode(Pathname)) {
+ if (Verbose)
+ std::cerr << "Trying to link bytecode file '" << Pathname << "'\n";
+
+ if (LinkInFile(HeadModule, Pathname, ErrorMessage, Verbose)) {
+ std::cerr << progname << ": Error linking in bytecode file '"
+ << Pathname << "': " << ErrorMessage << "\n";
+ 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.
+///
+void llvm::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) {
+ std::cerr << progname << ": WARNING: Cannot find library -l"
+ << Libraries[i] << "\n";
+ continue;
+ }
+ }
+
+ // 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)) {
+ std::cerr << progname << ": " << ErrorMessage
+ << ": Error linking in archive '" << Pathname << "' (-l"
+ << Libraries[i] << ")\n";
+ exit(1);
+ }
+ } else if (IsBytecode(Pathname)) {
+ if (Verbose)
+ std::cerr << "Trying to link bytecode file '" << Pathname
+ << "' (-l" << Libraries[i] << ")\n";
+
+ if (LinkInFile(HeadModule, Pathname, ErrorMessage, Verbose)) {
+ std::cerr << progname << ": " << ErrorMessage
+ << ": error linking in bytecode file '" << Pathname << "' (-l"
+ << Libraries[i] << ")\n";
+ exit(1);
+ }
+ }
+ }
+}