-//===----------------------------------------------------------------------===//
-// LLVM 'GCCLD' UTILITY
+//===- gccld.cpp - LLVM 'ld' compatible linker ----------------------------===//
//
// This utility is intended to be compatible with GCC, and follows standard
-// system ld conventions. As such, the default output file is ./a.out.
+// system 'ld' conventions. As such, the default output file is ./a.out.
// Additionally, this program outputs a shell script that is used to invoke LLI
// to execute the program. In this manner, the generated executable (a.out for
// example), is directly executable, whereas the bytecode file actually lives in
//
// Note that if someone (or a script) deletes the executable program generated,
// the .bc file will be left around. Considering that this is a temporary hack,
-// I'm not to worried about this.
+// I'm not too worried about this.
//
//===----------------------------------------------------------------------===//
#include "llvm/PassManager.h"
#include "llvm/Bytecode/Reader.h"
#include "llvm/Bytecode/WriteBytecodePass.h"
-#include "llvm/Transforms/CleanupGCCOutput.h"
-#include "llvm/Transforms/ConstantMerge.h"
+#include "llvm/Target/TargetData.h"
+#include "llvm/Transforms/IPO.h"
#include "llvm/Transforms/Scalar.h"
-#include "llvm/Transforms/IPO/GlobalDCE.h"
-#include "llvm/Transforms/IPO/Internalize.h"
#include "Support/CommandLine.h"
#include "Support/Signals.h"
#include <fstream>
#include <memory>
+#include <set>
#include <algorithm>
#include <sys/types.h> // For FileExists
#include <sys/stat.h>
-using std::cerr;
-cl::StringList InputFilenames("", "Load <arg> files, linking them together",
- cl::OneOrMore);
-cl::String OutputFilename("o", "Override output filename", cl::NoFlags,"a.out");
-cl::Flag Verbose ("v", "Print information about actions taken");
-cl::StringList LibPaths ("L", "Specify a library search path", cl::ZeroOrMore);
-cl::StringList Libraries ("l", "Specify libraries to link to", cl::ZeroOrMore);
-cl::Flag Strip ("s", "Strip symbol info from executable");
+namespace {
+ cl::list<std::string>
+ InputFilenames(cl::Positional, cl::desc("<input bytecode files>"),
+ cl::OneOrMore);
+
+ cl::opt<std::string>
+ OutputFilename("o", cl::desc("Override output filename"), cl::init("a.out"),
+ cl::value_desc("filename"));
+
+ cl::opt<bool>
+ Verbose("v", cl::desc("Print information about actions taken"));
+
+ cl::list<std::string>
+ LibPaths("L", cl::desc("Specify a library search path"), cl::Prefix,
+ cl::value_desc("directory"));
+
+ cl::list<std::string>
+ Libraries("l", cl::desc("Specify libraries to link to"), cl::Prefix,
+ cl::value_desc("library prefix"));
+
+ cl::opt<bool>
+ Strip("s", cl::desc("Strip symbol info from executable"));
+
+ cl::opt<bool>
+ NoInternalize("disable-internalize",
+ cl::desc("Do not mark all symbols as internal"));
+
+ cl::opt<bool>
+ LinkAsLibrary("link-as-library", cl::desc("Link the .bc files together as a"
+ " library, not an executable"));
+
+ // Compatibility options that are ignored, but support by LD
+ cl::opt<std::string>
+ CO3("soname", cl::Hidden, cl::desc("Compatibility option: ignored"));
+ cl::opt<std::string>
+ CO4("version-script", cl::Hidden, cl::desc("Compatibility option: ignored"));
+ cl::opt<bool>
+ CO5("eh-frame-hdr", cl::Hidden, cl::desc("Compatibility option: ignored"));
+ cl::opt<bool>
+ CO6("r", cl::Hidden, cl::desc("Compatibility option: ignored"));
+}
// FileExists - Return true if the specified string is an openable file...
static inline bool FileExists(const std::string &FN) {
return stat(FN.c_str(), &StatBuf) != -1;
}
-// LoadFile - Read the specified bytecode file in and return it. This routine
-// searches the link path for the specified file to try to find it...
-//
-static inline std::auto_ptr<Module> LoadFile(const std::string &FN) {
- std::string Filename = FN;
+
+// LoadObject - Read the specified "object file", which should not search the
+// library path to find it.
+static inline std::auto_ptr<Module> LoadObject(std::string FN,
+ std::string &OutErrorMessage) {
+ if (Verbose) std::cerr << "Loading '" << FN << "'\n";
+ if (!FileExists(FN)) {
+ // Attempt to load from the LLVM_LIB_SEARCH_PATH directory... if we would
+ // otherwise fail. This is used to locate objects like crtend.o.
+ //
+ char *SearchPath = getenv("LLVM_LIB_SEARCH_PATH");
+ if (SearchPath && FileExists(std::string(SearchPath)+"/"+FN))
+ FN = std::string(SearchPath)+"/"+FN;
+ else {
+ OutErrorMessage = "could not find input file '" + FN + "'!";
+ return std::auto_ptr<Module>();
+ }
+ }
+
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>();
+}
- unsigned NextLibPathIdx = 0;
- bool FoundAFile = false;
- while (1) {
- if (Verbose) cerr << "Loading '" << Filename << "'\n";
- if (FileExists(Filename)) FoundAFile = true;
- Module *Result = ParseBytecodeFile(Filename, &ErrorMessage);
- if (Result) return std::auto_ptr<Module>(Result); // Load successful!
+static Module *LoadSingleLibraryObject(const std::string &Filename) {
+ std::string ErrorMessage;
+ std::auto_ptr<Module> M = LoadObject(Filename, ErrorMessage);
+ if (M.get() == 0 && Verbose) {
+ std::cerr << "Error loading '" + Filename + "'";
+ if (!ErrorMessage.empty()) std::cerr << ": " << ErrorMessage;
+ std::cerr << "\n";
+ }
+
+ return M.release();
+}
- if (Verbose) {
- cerr << "Error opening bytecode file: '" << Filename << "'";
- if (ErrorMessage.size()) cerr << ": " << ErrorMessage;
- cerr << "\n";
+// IsArchive - Returns true iff FILENAME appears to be the name of an ar
+// archive file. It determines this by checking the magic string at the
+// beginning of the file.
+static 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;
+}
+
+// LoadLibraryExactName - This looks for a file with a known name and tries to
+// load it, similarly to LoadLibraryFromDirectory().
+static inline bool LoadLibraryExactName(const std::string &FileName,
+ std::vector<Module*> &Objects, bool &isArchive) {
+ if (Verbose) std::cerr << " Considering '" << FileName << "'\n";
+ if (FileExists(FileName)) {
+ if (IsArchive(FileName)) {
+ std::string ErrorMessage;
+ if (Verbose) std::cerr << " Loading '" << FileName << "'\n";
+ if (!ReadArchiveFile(FileName, Objects, &ErrorMessage)) {
+ isArchive = true;
+ return false; // Success!
+ }
+ if (Verbose) {
+ std::cerr << " Error loading archive '" + FileName + "'";
+ if (!ErrorMessage.empty()) std::cerr << ": " << ErrorMessage;
+ std::cerr << "\n";
+ }
+ } else {
+ if (Module *M = LoadSingleLibraryObject(FileName)) {
+ isArchive = false;
+ Objects.push_back(M);
+ return false;
+ }
}
-
- if (NextLibPathIdx == LibPaths.size()) break;
- Filename = LibPaths[NextLibPathIdx++] + "/" + FN;
}
+ return true;
+}
- if (FoundAFile)
- cerr << "Bytecode file '" << FN << "' corrupt! "
- << "Use 'gccld -v ...' for more info.\n";
- else
- cerr << "Could not locate bytecode file: '" << FN << "'\n";
- return std::auto_ptr<Module>();
+// LoadLibrary - Try to load a library named LIBNAME that contains
+// LLVM bytecode. If SEARCH is true, then search for a file named
+// libLIBNAME.{a,so,bc} in the current library search path. Otherwise,
+// assume LIBNAME is the real name of the library file. This method puts
+// the loaded modules into the Objects list, and sets isArchive to true if
+// a .a file was loaded. It returns true if no library is found or if an
+// error occurs; otherwise it returns false.
+//
+static inline bool LoadLibrary(const std::string &LibName,
+ std::vector<Module*> &Objects, bool &isArchive,
+ bool search, std::string &ErrorMessage) {
+ if (search) {
+ // First, try the current directory. Then, iterate over the
+ // directories in LibPaths, looking for a suitable match for LibName
+ // in each one.
+ for (unsigned NextLibPathIdx = 0; NextLibPathIdx != LibPaths.size();
+ ++NextLibPathIdx) {
+ std::string Directory = LibPaths[NextLibPathIdx] + "/";
+ if (!LoadLibraryExactName(Directory + "lib" + LibName + ".a",
+ Objects, isArchive))
+ return false;
+ if (!LoadLibraryExactName(Directory + "lib" + LibName + ".so",
+ Objects, isArchive))
+ return false;
+ if (!LoadLibraryExactName(Directory + "lib" + LibName + ".bc",
+ Objects, isArchive))
+ return false;
+ }
+ } else {
+ // If they said no searching, then assume LibName is the real name.
+ if (!LoadLibraryExactName(LibName, Objects, isArchive))
+ return false;
+ }
+ ErrorMessage = "error linking library '-l" + LibName+ "': library not found!";
+ return true;
}
+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)
+ if (I->hasName() && !I->isExternal() && !I->hasInternalLinkage())
+ DefinedSymbols.insert(I->getName());
+}
-int main(int argc, char **argv) {
- cl::ParseCommandLineOptions(argc, argv, " llvm linker for GCC\n",
- cl::EnableSingleLetterArgValue |
- cl::DisableSingleLetterArgGrouping);
- assert(InputFilenames.size() > 0 && "OneOrMore is not working");
+// GetAllUndefinedSymbols - This 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).
+//
+static 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
+}
- unsigned BaseArg = 0;
- std::string ErrorMessage;
- if (!Libraries.empty()) {
- // Sort libraries list...
- std::sort(Libraries.begin(), Libraries.end());
+static bool LinkLibrary(Module *M, const std::string &LibName,
+ bool search, std::string &ErrorMessage) {
+ 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!
+ }
- // Remove duplicate libraries entries...
- Libraries.erase(unique(Libraries.begin(), Libraries.end()),
- Libraries.end());
+ std::vector<Module*> Objects;
+ bool isArchive;
+ if (LoadLibrary(LibName, Objects, isArchive, search, ErrorMessage))
+ return true;
- // Add all of the libraries to the end of the link line...
- for (unsigned i = 0; i < Libraries.size(); ++i)
- InputFilenames.push_back("lib" + Libraries[i] + ".bc");
+ // Figure out which symbols are defined by all of the modules in the .a file
+ std::vector<std::set<std::string> > DefinedSymbols;
+ DefinedSymbols.resize(Objects.size());
+ for (unsigned i = 0; i != Objects.size(); ++i)
+ GetAllDefinedSymbols(Objects[i], DefinedSymbols[i]);
+
+ bool Linked = true;
+ while (Linked) { // While we are linking in object files, loop.
+ 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;
+}
+
+static int PrintAndReturn(const char *progname, const std::string &Message,
+ const std::string &Extra = "") {
+ std::cerr << progname << Extra << ": " << Message << "\n";
+ return 1;
+}
- std::auto_ptr<Module> Composite(LoadFile(InputFilenames[BaseArg]));
- if (Composite.get() == 0) return 1;
- for (unsigned i = BaseArg+1; i < InputFilenames.size(); ++i) {
- std::auto_ptr<Module> M(LoadFile(InputFilenames[i]));
- if (M.get() == 0) return 1;
+int main(int argc, char **argv) {
+ cl::ParseCommandLineOptions(argc, argv, " llvm linker for GCC\n");
+
+ std::string ErrorMessage;
+ std::auto_ptr<Module> Composite(LoadObject(InputFilenames[0], ErrorMessage));
+ if (Composite.get() == 0)
+ return PrintAndReturn(argv[0], ErrorMessage);
+
+ // We always look first in the current directory when searching for libraries.
+ LibPaths.insert(LibPaths.begin(), ".");
- if (Verbose) cerr << "Linking in '" << InputFilenames[i] << "'\n";
+ // If the user specied an extra search path in their environment, respect it.
+ if (char *SearchPath = getenv("LLVM_LIB_SEARCH_PATH"))
+ LibPaths.push_back(SearchPath);
- if (LinkModules(Composite.get(), M.get(), &ErrorMessage)) {
- cerr << "Error linking in '" << InputFilenames[i] << "': "
- << ErrorMessage << "\n";
- return 1;
+ for (unsigned i = 1; i < InputFilenames.size(); ++i) {
+ // 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(InputFilenames[i])) {
+ if (Verbose) std::cerr << "Linking archive '" << InputFilenames[i]
+ << "'\n";
+ if (LinkLibrary(Composite.get(), InputFilenames[i], false, ErrorMessage))
+ return PrintAndReturn(argv[0], ErrorMessage,
+ ": error linking in '" + InputFilenames[i] + "'");
+ continue;
}
+
+ std::auto_ptr<Module> M(LoadObject(InputFilenames[i], ErrorMessage));
+ if (M.get() == 0)
+ return PrintAndReturn(argv[0], ErrorMessage);
+
+ if (Verbose) std::cerr << "Linking in '" << InputFilenames[i] << "'\n";
+
+ if (LinkModules(Composite.get(), M.get(), &ErrorMessage))
+ return PrintAndReturn(argv[0], ErrorMessage,
+ ": error linking in '" + InputFilenames[i] + "'");
+ }
+
+ // Remove any consecutive duplicates of the same library...
+ Libraries.erase(std::unique(Libraries.begin(), Libraries.end()),
+ Libraries.end());
+
+ // Link in all of the libraries next...
+ for (unsigned i = 0; i != Libraries.size(); ++i) {
+ if (Verbose) std::cerr << "Linking in library: -l" << Libraries[i] << "\n";
+ if (LinkLibrary(Composite.get(), Libraries[i], true, ErrorMessage))
+ return PrintAndReturn(argv[0], ErrorMessage);
}
// In addition to just linking the input from GCC, we also want to spiff it up
//
PassManager Passes;
+ // Add an appropriate TargetData instance for this module...
+ Passes.add(new TargetData("gccld", Composite.get()));
+
// Linking modules together can lead to duplicated global constants, only keep
// one copy of each constant...
//
// arguments). This pass merges the two functions.
//
Passes.add(createFunctionResolvingPass());
+ Passes.add(createFunctionResolvingPass());
- // Now that composite has been compiled, scan through the module, looking for
- // a main function. If main is defined, mark all other functions internal.
+ if (!NoInternalize) {
+ // Now that composite has been compiled, scan through the module, looking
+ // for a main function. If main is defined, mark all other functions
+ // internal.
+ //
+ Passes.add(createInternalizePass());
+ }
+
+ // Remove unused arguments from functions...
+ //
+ Passes.add(createDeadArgEliminationPass());
+
+ // The FuncResolve pass may leave cruft around if functions were prototyped
+ // differently than they were defined. Remove this cruft.
+ //
+ Passes.add(createInstructionCombiningPass());
+
+ // Delete basic blocks, which optimization passes may have killed...
//
- Passes.add(createInternalizePass());
+ Passes.add(createCFGSimplificationPass());
// Now that we have optimized the program, discard unreachable functions...
//
Passes.add(createGlobalDCEPass());
// Add the pass that writes bytecode to the output file...
- std::ofstream Out((OutputFilename+".bc").c_str());
- if (!Out.good()) {
- cerr << "Error opening '" << OutputFilename << ".bc' for writing!\n";
- return 1;
- }
+ std::string RealBytecodeOutput = OutputFilename;
+ if (!LinkAsLibrary) RealBytecodeOutput += ".bc";
+ std::ofstream Out(RealBytecodeOutput.c_str());
+ if (!Out.good())
+ return PrintAndReturn(argv[0], "error opening '" + RealBytecodeOutput +
+ "' for writing!");
Passes.add(new WriteBytecodePass(&Out)); // Write bytecode to file...
// Make sure that the Out file gets unlink'd from the disk if we get a SIGINT
- RemoveFileOnSignal(OutputFilename+".bc");
+ RemoveFileOnSignal(RealBytecodeOutput);
// Run our queue of passes all at once now, efficiently.
Passes.run(*Composite.get());
Out.close();
- // Output the script to start the program...
- std::ofstream Out2(OutputFilename.c_str());
- if (!Out2.good()) {
- cerr << "Error opening '" << OutputFilename << "' for writing!\n";
- return 1;
- }
- Out2 << "#!/bin/sh\nlli -q $0.bc $*\n";
- Out2.close();
+ if (!LinkAsLibrary) {
+ // Output the script to start the program...
+ std::ofstream Out2(OutputFilename.c_str());
+ if (!Out2.good())
+ return PrintAndReturn(argv[0], "error opening '" + OutputFilename +
+ "' for writing!");
+ Out2 << "#!/bin/sh\nlli -q -abort-on-exception $0.bc $*\n";
+ Out2.close();
- // Make the script executable...
- chmod(OutputFilename.c_str(), 0755);
+ // Make the script executable...
+ chmod(OutputFilename.c_str(), 0755);
+ }
return 0;
}
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