//===- llvm-ld.cpp - LLVM 'ld' compatible linker --------------------------===// // // The LLVM Compiler Infrastructure // // This file is distributed under the University of Illinois Open Source // License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// // // This utility is intended to be compatible with GCC, and follows standard // 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 bitcode file actually lives in // the a.out.bc file generated by this program. // // 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 too worried about this. // //===----------------------------------------------------------------------===// #include "llvm/LinkAllVMCore.h" #include "llvm/Linker.h" #include "llvm/LLVMContext.h" #include "llvm/Support/Program.h" #include "llvm/Module.h" #include "llvm/PassManager.h" #include "llvm/Bitcode/ReaderWriter.h" #include "llvm/Target/TargetData.h" #include "llvm/Target/TargetMachine.h" #include "llvm/Support/CommandLine.h" #include "llvm/Support/FileUtilities.h" #include "llvm/Support/ManagedStatic.h" #include "llvm/Support/MemoryBuffer.h" #include "llvm/Support/PrettyStackTrace.h" #include "llvm/Support/SystemUtils.h" #include "llvm/Support/ToolOutputFile.h" #include "llvm/Support/Signals.h" #include "llvm/Config/config.h" #include <memory> #include <cstring> using namespace llvm; // Rightly this should go in a header file but it just seems such a waste. namespace llvm { extern void Optimize(Module*); } // Input/Output Options static cl::list<std::string> InputFilenames(cl::Positional, cl::OneOrMore, cl::desc("<input bitcode files>")); static cl::opt<std::string> OutputFilename("o", cl::init("a.out"), cl::desc("Override output filename"), cl::value_desc("filename")); static cl::opt<std::string> BitcodeOutputFilename("b", cl::init(""), cl::desc("Override bitcode output filename"), cl::value_desc("filename")); static cl::opt<bool> Verbose("v", cl::desc("Print information about actions taken")); static cl::list<std::string> LibPaths("L", cl::Prefix, cl::desc("Specify a library search path"), cl::value_desc("directory")); static cl::list<std::string> FrameworkPaths("F", cl::Prefix, cl::desc("Specify a framework search path"), cl::value_desc("directory")); static cl::list<std::string> Libraries("l", cl::Prefix, cl::desc("Specify libraries to link to"), cl::value_desc("library prefix")); static cl::list<std::string> Frameworks("framework", cl::desc("Specify frameworks to link to"), cl::value_desc("framework")); // Options to control the linking, optimization, and code gen processes static cl::opt<bool> LinkAsLibrary("link-as-library", cl::desc("Link the .bc files together as a library, not an executable")); static cl::alias Relink("r", cl::aliasopt(LinkAsLibrary), cl::desc("Alias for -link-as-library")); static cl::opt<bool> Native("native", cl::desc("Generate a native binary instead of a shell script")); static cl::opt<bool>NativeCBE("native-cbe", cl::desc("Generate a native binary with the C backend and GCC")); static cl::list<std::string> PostLinkOpts("post-link-opts", cl::value_desc("path"), cl::desc("Run one or more optimization programs after linking")); static cl::list<std::string> XLinker("Xlinker", cl::value_desc("option"), cl::desc("Pass options to the system linker")); // Compatibility options that llvm-ld ignores but are supported for // compatibility with LD static cl::opt<std::string> CO3("soname", cl::Hidden, cl::desc("Compatibility option: ignored")); static cl::opt<std::string> CO4("version-script", cl::Hidden, cl::desc("Compatibility option: ignored")); static cl::opt<bool> CO5("eh-frame-hdr", cl::Hidden, cl::desc("Compatibility option: ignored")); static cl::opt<std::string> CO6("h", cl::Hidden, cl::desc("Compatibility option: ignored")); static cl::opt<bool> CO7("start-group", cl::Hidden, cl::desc("Compatibility option: ignored")); static cl::opt<bool> CO8("end-group", cl::Hidden, cl::desc("Compatibility option: ignored")); static cl::opt<std::string> CO9("m", cl::Hidden, cl::desc("Compatibility option: ignored")); /// This is just for convenience so it doesn't have to be passed around /// everywhere. static std::string progname; /// FileRemover objects to clean up output files in the event of an error. static FileRemover OutputRemover; static FileRemover BitcodeOutputRemover; /// PrintAndExit - Prints a message to standard error and exits with error code /// /// Inputs: /// Message - The message to print to standard error. /// static void PrintAndExit(const std::string &Message, Module *M, int errcode = 1) { errs() << progname << ": " << Message << "\n"; delete M; llvm_shutdown(); exit(errcode); } static void PrintCommand(const std::vector<const char*> &args) { std::vector<const char*>::const_iterator I = args.begin(), E = args.end(); for (; I != E; ++I) if (*I) errs() << "'" << *I << "'" << " "; errs() << "\n"; } /// CopyEnv - This function takes an array of environment variables and makes a /// copy of it. This copy can then be manipulated any way the caller likes /// without affecting the process's real environment. /// /// Inputs: /// envp - An array of C strings containing an environment. /// /// Return value: /// NULL - An error occurred. /// /// Otherwise, a pointer to a new array of C strings is returned. Every string /// in the array is a duplicate of the one in the original array (i.e. we do /// not copy the char *'s from one array to another). /// static char ** CopyEnv(char ** const envp) { // Count the number of entries in the old list; unsigned entries; // The number of entries in the old environment list for (entries = 0; envp[entries] != NULL; entries++) /*empty*/; // Add one more entry for the NULL pointer that ends the list. ++entries; // If there are no entries at all, just return NULL. if (entries == 0) return NULL; // Allocate a new environment list. char **newenv = new char* [entries]; if (newenv == NULL) return NULL; // Make a copy of the list. Don't forget the NULL that ends the list. entries = 0; while (envp[entries] != NULL) { size_t len = strlen(envp[entries]) + 1; newenv[entries] = new char[len]; memcpy(newenv[entries], envp[entries], len); ++entries; } newenv[entries] = NULL; return newenv; } /// RemoveEnv - Remove the specified environment variable from the environment /// array. /// /// Inputs: /// name - The name of the variable to remove. It cannot be NULL. /// envp - The array of environment variables. It cannot be NULL. /// /// Notes: /// This is mainly done because functions to remove items from the environment /// are not available across all platforms. In particular, Solaris does not /// seem to have an unsetenv() function or a setenv() function (or they are /// undocumented if they do exist). /// static void RemoveEnv(const char * name, char ** const envp) { for (unsigned index=0; envp[index] != NULL; index++) { // Find the first equals sign in the array and make it an EOS character. char *p = strchr (envp[index], '='); if (p == NULL) continue; else *p = '\0'; // Compare the two strings. If they are equal, zap this string. // Otherwise, restore it. if (!strcmp(name, envp[index])) *envp[index] = '\0'; else *p = '='; } return; } /// GenerateBitcode - generates a bitcode file from the module provided void GenerateBitcode(Module* M, const std::string& FileName) { if (Verbose) errs() << "Generating Bitcode To " << FileName << '\n'; // Create the output file. std::string ErrorInfo; tool_output_file Out(FileName.c_str(), ErrorInfo, raw_fd_ostream::F_Binary); if (!ErrorInfo.empty()) { PrintAndExit(ErrorInfo, M); return; } // Write it out WriteBitcodeToFile(M, Out.os()); Out.keep(); } /// GenerateAssembly - generates a native assembly language source file from the /// specified bitcode file. /// /// Inputs: /// InputFilename - The name of the input bitcode file. /// OutputFilename - The name of the file to generate. /// llc - The pathname to use for LLC. /// envp - The environment to use when running LLC. /// /// Return non-zero value on error. /// static int GenerateAssembly(const std::string &OutputFilename, const std::string &InputFilename, const sys::Path &llc, std::string &ErrMsg ) { // Run LLC to convert the bitcode file into assembly code. std::vector<const char*> args; args.push_back(llc.c_str()); // We will use GCC to assemble the program so set the assembly syntax to AT&T, // regardless of what the target in the bitcode file is. args.push_back("-x86-asm-syntax=att"); args.push_back("-o"); args.push_back(OutputFilename.c_str()); args.push_back(InputFilename.c_str()); args.push_back(0); if (Verbose) { errs() << "Generating Assembly With: \n"; PrintCommand(args); } return sys::Program::ExecuteAndWait(llc, &args[0], 0, 0, 0, 0, &ErrMsg); } /// GenerateCFile - generates a C source file from the specified bitcode file. static int GenerateCFile(const std::string &OutputFile, const std::string &InputFile, const sys::Path &llc, std::string& ErrMsg) { // Run LLC to convert the bitcode file into C. std::vector<const char*> args; args.push_back(llc.c_str()); args.push_back("-march=c"); args.push_back("-o"); args.push_back(OutputFile.c_str()); args.push_back(InputFile.c_str()); args.push_back(0); if (Verbose) { errs() << "Generating C Source With: \n"; PrintCommand(args); } return sys::Program::ExecuteAndWait(llc, &args[0], 0, 0, 0, 0, &ErrMsg); } /// GenerateNative - generates a native object file from the /// specified bitcode file. /// /// Inputs: /// InputFilename - The name of the input bitcode file. /// OutputFilename - The name of the file to generate. /// NativeLinkItems - The native libraries, files, code with which to link /// LibPaths - The list of directories in which to find libraries. /// FrameworksPaths - The list of directories in which to find frameworks. /// Frameworks - The list of frameworks (dynamic libraries) /// gcc - The pathname to use for GGC. /// envp - A copy of the process's current environment. /// /// Outputs: /// None. /// /// Returns non-zero value on error. /// static int GenerateNative(const std::string &OutputFilename, const std::string &InputFilename, const Linker::ItemList &LinkItems, const sys::Path &gcc, char ** const envp, std::string& ErrMsg) { // Remove these environment variables from the environment of the // programs that we will execute. It appears that GCC sets these // environment variables so that the programs it uses can configure // themselves identically. // // However, when we invoke GCC below, we want it to use its normal // configuration. Hence, we must sanitize its environment. char ** clean_env = CopyEnv(envp); if (clean_env == NULL) return 1; RemoveEnv("LIBRARY_PATH", clean_env); RemoveEnv("COLLECT_GCC_OPTIONS", clean_env); RemoveEnv("GCC_EXEC_PREFIX", clean_env); RemoveEnv("COMPILER_PATH", clean_env); RemoveEnv("COLLECT_GCC", clean_env); // Run GCC to assemble and link the program into native code. // // Note: // We can't just assemble and link the file with the system assembler // and linker because we don't know where to put the _start symbol. // GCC mysteriously knows how to do it. std::vector<std::string> args; args.push_back(gcc.c_str()); args.push_back("-fno-strict-aliasing"); args.push_back("-O3"); args.push_back("-o"); args.push_back(OutputFilename); args.push_back(InputFilename); // Add in the library and framework paths for (unsigned index = 0; index < LibPaths.size(); index++) { args.push_back("-L" + LibPaths[index]); } for (unsigned index = 0; index < FrameworkPaths.size(); index++) { args.push_back("-F" + FrameworkPaths[index]); } // Add the requested options for (unsigned index = 0; index < XLinker.size(); index++) args.push_back(XLinker[index]); // Add in the libraries to link. for (unsigned index = 0; index < LinkItems.size(); index++) if (LinkItems[index].first != "crtend") { if (LinkItems[index].second) args.push_back("-l" + LinkItems[index].first); else args.push_back(LinkItems[index].first); } // Add in frameworks to link. for (unsigned index = 0; index < Frameworks.size(); index++) { args.push_back("-framework"); args.push_back(Frameworks[index]); } // Now that "args" owns all the std::strings for the arguments, call the c_str // method to get the underlying string array. We do this game so that the // std::string array is guaranteed to outlive the const char* array. std::vector<const char *> Args; for (unsigned i = 0, e = args.size(); i != e; ++i) Args.push_back(args[i].c_str()); Args.push_back(0); if (Verbose) { errs() << "Generating Native Executable With:\n"; PrintCommand(Args); } // Run the compiler to assembly and link together the program. int R = sys::Program::ExecuteAndWait( gcc, &Args[0], const_cast<const char **>(clean_env), 0, 0, 0, &ErrMsg); delete [] clean_env; return R; } /// EmitShellScript - Output the wrapper file that invokes the JIT on the LLVM /// bitcode file for the program. static void EmitShellScript(char **argv, Module *M) { if (Verbose) errs() << "Emitting Shell Script\n"; #if defined(_WIN32) // Windows doesn't support #!/bin/sh style shell scripts in .exe files. To // support windows systems, we copy the llvm-stub.exe executable from the // build tree to the destination file. std::string ErrMsg; sys::Path llvmstub = PrependMainExecutablePath("llvm-stub", argv[0], (void *)(intptr_t)&Optimize); if (llvmstub.isEmpty()) PrintAndExit("Could not find llvm-stub.exe executable!", M); if (0 != sys::CopyFile(sys::Path(OutputFilename), llvmstub, &ErrMsg)) PrintAndExit(ErrMsg, M); return; #endif // Output the script to start the program... std::string ErrorInfo; tool_output_file Out2(OutputFilename.c_str(), ErrorInfo); if (!ErrorInfo.empty()) PrintAndExit(ErrorInfo, M); Out2.os() << "#!/bin/sh\n"; // Allow user to setenv LLVMINTERP if lli is not in their PATH. Out2.os() << "lli=${LLVMINTERP-lli}\n"; Out2.os() << "exec $lli \\\n"; // gcc accepts -l<lib> and implicitly searches /lib and /usr/lib. LibPaths.push_back("/lib"); LibPaths.push_back("/usr/lib"); LibPaths.push_back("/usr/X11R6/lib"); // We don't need to link in libc! In fact, /usr/lib/libc.so may not be a // shared object at all! See RH 8: plain text. std::vector<std::string>::iterator libc = std::find(Libraries.begin(), Libraries.end(), "c"); if (libc != Libraries.end()) Libraries.erase(libc); // List all the shared object (native) libraries this executable will need // on the command line, so that we don't have to do this manually! for (std::vector<std::string>::iterator i = Libraries.begin(), e = Libraries.end(); i != e; ++i) { // try explicit -L arguments first: sys::Path FullLibraryPath; for (cl::list<std::string>::const_iterator P = LibPaths.begin(), E = LibPaths.end(); P != E; ++P) { FullLibraryPath = *P; FullLibraryPath.appendComponent("lib" + *i); FullLibraryPath.appendSuffix(sys::Path::GetDLLSuffix()); if (!FullLibraryPath.isEmpty()) { if (!FullLibraryPath.isDynamicLibrary()) { // Not a native shared library; mark as invalid FullLibraryPath = sys::Path(); } else break; } } if (FullLibraryPath.isEmpty()) FullLibraryPath = sys::Path::FindLibrary(*i); if (!FullLibraryPath.isEmpty()) Out2.os() << " -load=" << FullLibraryPath.str() << " \\\n"; } Out2.os() << " " << BitcodeOutputFilename << " ${1+\"$@\"}\n"; Out2.keep(); } // BuildLinkItems -- This function generates a LinkItemList for the LinkItems // linker function by combining the Files and Libraries in the order they were // declared on the command line. static void BuildLinkItems( Linker::ItemList& Items, const cl::list<std::string>& Files, const cl::list<std::string>& Libraries) { // Build the list of linkage items for LinkItems. cl::list<std::string>::const_iterator fileIt = Files.begin(); cl::list<std::string>::const_iterator libIt = Libraries.begin(); int libPos = -1, filePos = -1; while ( libIt != Libraries.end() || fileIt != Files.end() ) { if (libIt != Libraries.end()) libPos = Libraries.getPosition(libIt - Libraries.begin()); else libPos = -1; if (fileIt != Files.end()) filePos = Files.getPosition(fileIt - Files.begin()); else filePos = -1; if (filePos != -1 && (libPos == -1 || filePos < libPos)) { // Add a source file Items.push_back(std::make_pair(*fileIt++, false)); } else if (libPos != -1 && (filePos == -1 || libPos < filePos)) { // Add a library Items.push_back(std::make_pair(*libIt++, true)); } } } int main(int argc, char **argv, char **envp) { // Print a stack trace if we signal out. sys::PrintStackTraceOnErrorSignal(); PrettyStackTraceProgram X(argc, argv); LLVMContext &Context = getGlobalContext(); llvm_shutdown_obj Y; // Call llvm_shutdown() on exit. // Initialize passes PassRegistry &Registry = *PassRegistry::getPassRegistry(); initializeCore(Registry); initializeScalarOpts(Registry); initializeIPO(Registry); initializeAnalysis(Registry); initializeIPA(Registry); initializeTransformUtils(Registry); initializeInstCombine(Registry); initializeTarget(Registry); // Initial global variable above for convenience printing of program name. progname = sys::path::stem(argv[0]); // Parse the command line options cl::ParseCommandLineOptions(argc, argv, "llvm linker\n"); #if defined(_WIN32) || defined(__CYGWIN__) if (!LinkAsLibrary) { // Default to "a.exe" instead of "a.out". if (OutputFilename.getNumOccurrences() == 0) OutputFilename = "a.exe"; // If there is no suffix add an "exe" one. if (sys::path::extension(OutputFilename).empty()) OutputFilename.append(".exe"); } #endif // Generate the bitcode for the optimized module. // If -b wasn't specified, use the name specified // with -o to construct BitcodeOutputFilename. if (BitcodeOutputFilename.empty()) { BitcodeOutputFilename = OutputFilename; if (!LinkAsLibrary) BitcodeOutputFilename += ".bc"; } // Arrange for the bitcode output file to be deleted on any errors. BitcodeOutputRemover.setFile(BitcodeOutputFilename); sys::RemoveFileOnSignal(sys::Path(BitcodeOutputFilename)); // Arrange for the output file to be deleted on any errors. if (!LinkAsLibrary) { OutputRemover.setFile(OutputFilename); sys::RemoveFileOnSignal(sys::Path(OutputFilename)); } // Construct a Linker (now that Verbose is set) Linker TheLinker(progname, OutputFilename, Context, Verbose); // Keep track of the native link items (versus the bitcode items) Linker::ItemList NativeLinkItems; // Add library paths to the linker TheLinker.addPaths(LibPaths); TheLinker.addSystemPaths(); // Remove any consecutive duplicates of the same library... Libraries.erase(std::unique(Libraries.begin(), Libraries.end()), Libraries.end()); if (LinkAsLibrary) { std::vector<sys::Path> Files; for (unsigned i = 0; i < InputFilenames.size(); ++i ) Files.push_back(sys::Path(InputFilenames[i])); if (TheLinker.LinkInFiles(Files)) return 1; // Error already printed // The libraries aren't linked in but are noted as "dependent" in the // module. for (cl::list<std::string>::const_iterator I = Libraries.begin(), E = Libraries.end(); I != E ; ++I) { TheLinker.getModule()->addLibrary(*I); } } else { // Build a list of the items from our command line Linker::ItemList Items; BuildLinkItems(Items, InputFilenames, Libraries); // Link all the items together if (TheLinker.LinkInItems(Items, NativeLinkItems) ) return 1; // Error already printed } std::auto_ptr<Module> Composite(TheLinker.releaseModule()); // Optimize the module Optimize(Composite.get()); // Generate the bitcode output. GenerateBitcode(Composite.get(), BitcodeOutputFilename); // If we are not linking a library, generate either a native executable // or a JIT shell script, depending upon what the user wants. if (!LinkAsLibrary) { // If the user wants to run a post-link optimization, run it now. if (!PostLinkOpts.empty()) { std::vector<std::string> opts = PostLinkOpts; for (std::vector<std::string>::iterator I = opts.begin(), E = opts.end(); I != E; ++I) { sys::Path prog(*I); if (!prog.canExecute()) { prog = sys::Program::FindProgramByName(*I); if (prog.isEmpty()) PrintAndExit(std::string("Optimization program '") + *I + "' is not found or not executable.", Composite.get()); } // Get the program arguments sys::Path tmp_output("opt_result"); std::string ErrMsg; if (tmp_output.createTemporaryFileOnDisk(true, &ErrMsg)) PrintAndExit(ErrMsg, Composite.get()); const char* args[4]; args[0] = I->c_str(); args[1] = BitcodeOutputFilename.c_str(); args[2] = tmp_output.c_str(); args[3] = 0; if (0 == sys::Program::ExecuteAndWait(prog, args, 0,0,0,0, &ErrMsg)) { if (tmp_output.isBitcodeFile()) { sys::Path target(BitcodeOutputFilename); target.eraseFromDisk(); if (tmp_output.renamePathOnDisk(target, &ErrMsg)) PrintAndExit(ErrMsg, Composite.get(), 2); } else PrintAndExit("Post-link optimization output is not bitcode", Composite.get()); } else { PrintAndExit(ErrMsg, Composite.get()); } } } // If the user wants to generate a native executable, compile it from the // bitcode file. // // Otherwise, create a script that will run the bitcode through the JIT. if (Native) { // Name of the Assembly Language output file sys::Path AssemblyFile ( OutputFilename); AssemblyFile.appendSuffix("s"); // Mark the output files for removal. FileRemover AssemblyFileRemover(AssemblyFile.str()); sys::RemoveFileOnSignal(AssemblyFile); // Determine the locations of the llc and gcc programs. sys::Path llc = PrependMainExecutablePath("llc", argv[0], (void *)(intptr_t)&Optimize); if (llc.isEmpty()) PrintAndExit("Failed to find llc", Composite.get()); sys::Path gcc = sys::Program::FindProgramByName("gcc"); if (gcc.isEmpty()) PrintAndExit("Failed to find gcc", Composite.get()); // Generate an assembly language file for the bitcode. std::string ErrMsg; if (0 != GenerateAssembly(AssemblyFile.str(), BitcodeOutputFilename, llc, ErrMsg)) PrintAndExit(ErrMsg, Composite.get()); if (0 != GenerateNative(OutputFilename, AssemblyFile.str(), NativeLinkItems, gcc, envp, ErrMsg)) PrintAndExit(ErrMsg, Composite.get()); } else if (NativeCBE) { sys::Path CFile (OutputFilename); CFile.appendSuffix("cbe.c"); // Mark the output files for removal. FileRemover CFileRemover(CFile.str()); sys::RemoveFileOnSignal(CFile); // Determine the locations of the llc and gcc programs. sys::Path llc = PrependMainExecutablePath("llc", argv[0], (void *)(intptr_t)&Optimize); if (llc.isEmpty()) PrintAndExit("Failed to find llc", Composite.get()); sys::Path gcc = sys::Program::FindProgramByName("gcc"); if (gcc.isEmpty()) PrintAndExit("Failed to find gcc", Composite.get()); // Generate an assembly language file for the bitcode. std::string ErrMsg; if (GenerateCFile(CFile.str(), BitcodeOutputFilename, llc, ErrMsg)) PrintAndExit(ErrMsg, Composite.get()); if (GenerateNative(OutputFilename, CFile.str(), NativeLinkItems, gcc, envp, ErrMsg)) PrintAndExit(ErrMsg, Composite.get()); } else { EmitShellScript(argv, Composite.get()); } // Make the script executable... std::string ErrMsg; if (sys::Path(OutputFilename).makeExecutableOnDisk(&ErrMsg)) PrintAndExit(ErrMsg, Composite.get()); // Make the bitcode file readable and directly executable in LLEE as well if (sys::Path(BitcodeOutputFilename).makeExecutableOnDisk(&ErrMsg)) PrintAndExit(ErrMsg, Composite.get()); if (sys::Path(BitcodeOutputFilename).makeReadableOnDisk(&ErrMsg)) PrintAndExit(ErrMsg, Composite.get()); } // Operations which may fail are now complete. BitcodeOutputRemover.releaseFile(); if (!LinkAsLibrary) OutputRemover.releaseFile(); // Graceful exit return 0; }