1 //===- llvm-ld.cpp - LLVM 'ld' compatible linker --------------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This utility is intended to be compatible with GCC, and follows standard
11 // system 'ld' conventions. As such, the default output file is ./a.out.
12 // Additionally, this program outputs a shell script that is used to invoke LLI
13 // to execute the program. In this manner, the generated executable (a.out for
14 // example), is directly executable, whereas the bitcode file actually lives in
15 // the a.out.bc file generated by this program. Also, Force is on by default.
17 // Note that if someone (or a script) deletes the executable program generated,
18 // the .bc file will be left around. Considering that this is a temporary hack,
19 // I'm not too worried about this.
21 //===----------------------------------------------------------------------===//
23 #include "llvm/LinkAllVMCore.h"
24 #include "llvm/Linker.h"
25 #include "llvm/System/Program.h"
26 #include "llvm/Module.h"
27 #include "llvm/PassManager.h"
28 #include "llvm/Bitcode/ReaderWriter.h"
29 #include "llvm/Target/TargetData.h"
30 #include "llvm/Target/TargetMachine.h"
31 #include "llvm/Target/TargetMachineRegistry.h"
32 #include "llvm/Support/CommandLine.h"
33 #include "llvm/Support/FileUtilities.h"
34 #include "llvm/Support/ManagedStatic.h"
35 #include "llvm/Support/MemoryBuffer.h"
36 #include "llvm/Support/Streams.h"
37 #include "llvm/Support/SystemUtils.h"
38 #include "llvm/System/Signals.h"
39 #include "llvm/Config/config.h"
45 // Input/Output Options
46 static cl::list<std::string> InputFilenames(cl::Positional, cl::OneOrMore,
47 cl::desc("<input bitcode files>"));
49 static cl::opt<std::string> OutputFilename("o", cl::init("a.out"),
50 cl::desc("Override output filename"),
51 cl::value_desc("filename"));
53 static cl::opt<bool> Verbose("v",
54 cl::desc("Print information about actions taken"));
56 static cl::list<std::string> LibPaths("L", cl::Prefix,
57 cl::desc("Specify a library search path"),
58 cl::value_desc("directory"));
60 static cl::list<std::string> FrameworkPaths("F", cl::Prefix,
61 cl::desc("Specify a framework search path"),
62 cl::value_desc("directory"));
64 static cl::list<std::string> Libraries("l", cl::Prefix,
65 cl::desc("Specify libraries to link to"),
66 cl::value_desc("library prefix"));
68 static cl::list<std::string> Frameworks("framework",
69 cl::desc("Specify frameworks to link to"),
70 cl::value_desc("framework"));
72 // Options to control the linking, optimization, and code gen processes
73 static cl::opt<bool> LinkAsLibrary("link-as-library",
74 cl::desc("Link the .bc files together as a library, not an executable"));
76 static cl::alias Relink("r", cl::aliasopt(LinkAsLibrary),
77 cl::desc("Alias for -link-as-library"));
79 static cl::opt<bool> Native("native",
80 cl::desc("Generate a native binary instead of a shell script"));
82 static cl::opt<bool>NativeCBE("native-cbe",
83 cl::desc("Generate a native binary with the C backend and GCC"));
85 static cl::list<std::string> PostLinkOpts("post-link-opts",
86 cl::value_desc("path"),
87 cl::desc("Run one or more optimization programs after linking"));
89 static cl::list<std::string> XLinker("Xlinker", cl::value_desc("option"),
90 cl::desc("Pass options to the system linker"));
92 // Compatibility options that llvm-ld ignores but are supported for
93 // compatibility with LD
94 static cl::opt<std::string> CO3("soname", cl::Hidden,
95 cl::desc("Compatibility option: ignored"));
97 static cl::opt<std::string> CO4("version-script", cl::Hidden,
98 cl::desc("Compatibility option: ignored"));
100 static cl::opt<bool> CO5("eh-frame-hdr", cl::Hidden,
101 cl::desc("Compatibility option: ignored"));
103 static cl::opt<std::string> CO6("h", cl::Hidden,
104 cl::desc("Compatibility option: ignored"));
106 static cl::opt<bool> CO7("start-group", cl::Hidden,
107 cl::desc("Compatibility option: ignored"));
109 static cl::opt<bool> CO8("end-group", cl::Hidden,
110 cl::desc("Compatibility option: ignored"));
112 static cl::opt<std::string> CO9("m", cl::Hidden,
113 cl::desc("Compatibility option: ignored"));
115 /// This is just for convenience so it doesn't have to be passed around
117 static std::string progname;
119 /// PrintAndExit - Prints a message to standard error and exits with error code
122 /// Message - The message to print to standard error.
124 static void PrintAndExit(const std::string &Message, int errcode = 1) {
125 cerr << progname << ": " << Message << "\n";
130 static void PrintCommand(const std::vector<const char*> &args) {
131 std::vector<const char*>::const_iterator I = args.begin(), E = args.end();
134 cout << "'" << *I << "'" << " ";
135 cout << "\n" << std::flush;
138 /// CopyEnv - This function takes an array of environment variables and makes a
139 /// copy of it. This copy can then be manipulated any way the caller likes
140 /// without affecting the process's real environment.
143 /// envp - An array of C strings containing an environment.
146 /// NULL - An error occurred.
148 /// Otherwise, a pointer to a new array of C strings is returned. Every string
149 /// in the array is a duplicate of the one in the original array (i.e. we do
150 /// not copy the char *'s from one array to another).
152 static char ** CopyEnv(char ** const envp) {
153 // Count the number of entries in the old list;
154 unsigned entries; // The number of entries in the old environment list
155 for (entries = 0; envp[entries] != NULL; entries++)
158 // Add one more entry for the NULL pointer that ends the list.
161 // If there are no entries at all, just return NULL.
165 // Allocate a new environment list.
166 char **newenv = new char* [entries];
167 if ((newenv = new char* [entries]) == NULL)
170 // Make a copy of the list. Don't forget the NULL that ends the list.
172 while (envp[entries] != NULL) {
173 newenv[entries] = new char[strlen (envp[entries]) + 1];
174 strcpy (newenv[entries], envp[entries]);
177 newenv[entries] = NULL;
183 /// RemoveEnv - Remove the specified environment variable from the environment
187 /// name - The name of the variable to remove. It cannot be NULL.
188 /// envp - The array of environment variables. It cannot be NULL.
191 /// This is mainly done because functions to remove items from the environment
192 /// are not available across all platforms. In particular, Solaris does not
193 /// seem to have an unsetenv() function or a setenv() function (or they are
194 /// undocumented if they do exist).
196 static void RemoveEnv(const char * name, char ** const envp) {
197 for (unsigned index=0; envp[index] != NULL; index++) {
198 // Find the first equals sign in the array and make it an EOS character.
199 char *p = strchr (envp[index], '=');
205 // Compare the two strings. If they are equal, zap this string.
206 // Otherwise, restore it.
207 if (!strcmp(name, envp[index]))
216 /// GenerateBitcode - generates a bitcode file from the module provided
217 void GenerateBitcode(Module* M, const std::string& FileName) {
220 cout << "Generating Bitcode To " << FileName << '\n';
222 // Create the output file.
223 std::ios::openmode io_mode = std::ios::out | std::ios::trunc |
225 std::ofstream Out(FileName.c_str(), io_mode);
227 PrintAndExit("error opening '" + FileName + "' for writing!");
229 // Ensure that the bitcode file gets removed from the disk if we get a
230 // terminating signal.
231 sys::RemoveFileOnSignal(sys::Path(FileName));
234 WriteBitcodeToFile(M, Out);
236 // Close the bitcode file.
240 /// GenerateAssembly - generates a native assembly language source file from the
241 /// specified bitcode file.
244 /// InputFilename - The name of the input bitcode file.
245 /// OutputFilename - The name of the file to generate.
246 /// llc - The pathname to use for LLC.
247 /// envp - The environment to use when running LLC.
249 /// Return non-zero value on error.
251 static int GenerateAssembly(const std::string &OutputFilename,
252 const std::string &InputFilename,
253 const sys::Path &llc,
254 std::string &ErrMsg ) {
255 // Run LLC to convert the bitcode file into assembly code.
256 std::vector<const char*> args;
257 args.push_back(llc.c_str());
258 // We will use GCC to assemble the program so set the assembly syntax to AT&T,
259 // regardless of what the target in the bitcode file is.
260 args.push_back("-x86-asm-syntax=att");
261 args.push_back("-f");
262 args.push_back("-o");
263 args.push_back(OutputFilename.c_str());
264 args.push_back(InputFilename.c_str());
268 cout << "Generating Assembly With: \n";
272 return sys::Program::ExecuteAndWait(llc, &args[0], 0, 0, 0, 0, &ErrMsg);
275 /// GenerateCFile - generates a C source file from the specified bitcode file.
276 static int GenerateCFile(const std::string &OutputFile,
277 const std::string &InputFile,
278 const sys::Path &llc,
279 std::string& ErrMsg) {
280 // Run LLC to convert the bitcode file into C.
281 std::vector<const char*> args;
282 args.push_back(llc.c_str());
283 args.push_back("-march=c");
284 args.push_back("-f");
285 args.push_back("-o");
286 args.push_back(OutputFile.c_str());
287 args.push_back(InputFile.c_str());
291 cout << "Generating C Source With: \n";
295 return sys::Program::ExecuteAndWait(llc, &args[0], 0, 0, 0, 0, &ErrMsg);
298 /// GenerateNative - generates a native object file from the
299 /// specified bitcode file.
302 /// InputFilename - The name of the input bitcode file.
303 /// OutputFilename - The name of the file to generate.
304 /// NativeLinkItems - The native libraries, files, code with which to link
305 /// LibPaths - The list of directories in which to find libraries.
306 /// FrameworksPaths - The list of directories in which to find frameworks.
307 /// Frameworks - The list of frameworks (dynamic libraries)
308 /// gcc - The pathname to use for GGC.
309 /// envp - A copy of the process's current environment.
314 /// Returns non-zero value on error.
316 static int GenerateNative(const std::string &OutputFilename,
317 const std::string &InputFilename,
318 const Linker::ItemList &LinkItems,
319 const sys::Path &gcc, char ** const envp,
320 std::string& ErrMsg) {
321 // Remove these environment variables from the environment of the
322 // programs that we will execute. It appears that GCC sets these
323 // environment variables so that the programs it uses can configure
324 // themselves identically.
326 // However, when we invoke GCC below, we want it to use its normal
327 // configuration. Hence, we must sanitize its environment.
328 char ** clean_env = CopyEnv(envp);
329 if (clean_env == NULL)
331 RemoveEnv("LIBRARY_PATH", clean_env);
332 RemoveEnv("COLLECT_GCC_OPTIONS", clean_env);
333 RemoveEnv("GCC_EXEC_PREFIX", clean_env);
334 RemoveEnv("COMPILER_PATH", clean_env);
335 RemoveEnv("COLLECT_GCC", clean_env);
338 // Run GCC to assemble and link the program into native code.
341 // We can't just assemble and link the file with the system assembler
342 // and linker because we don't know where to put the _start symbol.
343 // GCC mysteriously knows how to do it.
344 std::vector<std::string> args;
345 args.push_back(gcc.c_str());
346 args.push_back("-fno-strict-aliasing");
347 args.push_back("-O3");
348 args.push_back("-o");
349 args.push_back(OutputFilename);
350 args.push_back(InputFilename);
352 // Add in the library and framework paths
353 for (unsigned index = 0; index < LibPaths.size(); index++) {
354 args.push_back("-L" + LibPaths[index]);
356 for (unsigned index = 0; index < FrameworkPaths.size(); index++) {
357 args.push_back("-F" + FrameworkPaths[index]);
360 // Add the requested options
361 for (unsigned index = 0; index < XLinker.size(); index++)
362 args.push_back(XLinker[index]);
364 // Add in the libraries to link.
365 for (unsigned index = 0; index < LinkItems.size(); index++)
366 if (LinkItems[index].first != "crtend") {
367 if (LinkItems[index].second)
368 args.push_back("-l" + LinkItems[index].first);
370 args.push_back(LinkItems[index].first);
373 // Add in frameworks to link.
374 for (unsigned index = 0; index < Frameworks.size(); index++) {
375 args.push_back("-framework");
376 args.push_back(Frameworks[index]);
379 // Now that "args" owns all the std::strings for the arguments, call the c_str
380 // method to get the underlying string array. We do this game so that the
381 // std::string array is guaranteed to outlive the const char* array.
382 std::vector<const char *> Args;
383 for (unsigned i = 0, e = args.size(); i != e; ++i)
384 Args.push_back(args[i].c_str());
388 cout << "Generating Native Executable With:\n";
392 // Run the compiler to assembly and link together the program.
393 int R = sys::Program::ExecuteAndWait(
394 gcc, &Args[0], (const char**)clean_env, 0, 0, 0, &ErrMsg);
399 /// EmitShellScript - Output the wrapper file that invokes the JIT on the LLVM
400 /// bitcode file for the program.
401 static void EmitShellScript(char **argv) {
403 cout << "Emitting Shell Script\n";
404 #if defined(_WIN32) || defined(__CYGWIN__)
405 // Windows doesn't support #!/bin/sh style shell scripts in .exe files. To
406 // support windows systems, we copy the llvm-stub.exe executable from the
407 // build tree to the destination file.
409 sys::Path llvmstub = FindExecutable("llvm-stub.exe", argv[0]);
410 if (llvmstub.isEmpty())
411 PrintAndExit("Could not find llvm-stub.exe executable!");
413 if (0 != sys::CopyFile(sys::Path(OutputFilename), llvmstub, &ErrMsg))
414 PrintAndExit(ErrMsg);
419 // Output the script to start the program...
420 std::ofstream Out2(OutputFilename.c_str());
422 PrintAndExit("error opening '" + OutputFilename + "' for writing!");
424 Out2 << "#!/bin/sh\n";
425 // Allow user to setenv LLVMINTERP if lli is not in their PATH.
426 Out2 << "lli=${LLVMINTERP-lli}\n";
427 Out2 << "exec $lli \\\n";
428 // gcc accepts -l<lib> and implicitly searches /lib and /usr/lib.
429 LibPaths.push_back("/lib");
430 LibPaths.push_back("/usr/lib");
431 LibPaths.push_back("/usr/X11R6/lib");
432 // We don't need to link in libc! In fact, /usr/lib/libc.so may not be a
433 // shared object at all! See RH 8: plain text.
434 std::vector<std::string>::iterator libc =
435 std::find(Libraries.begin(), Libraries.end(), "c");
436 if (libc != Libraries.end()) Libraries.erase(libc);
437 // List all the shared object (native) libraries this executable will need
438 // on the command line, so that we don't have to do this manually!
439 for (std::vector<std::string>::iterator i = Libraries.begin(),
440 e = Libraries.end(); i != e; ++i) {
441 // try explicit -L arguments first:
442 sys::Path FullLibraryPath;
443 for (cl::list<std::string>::const_iterator P = LibPaths.begin(),
444 E = LibPaths.end(); P != E; ++P) {
445 FullLibraryPath = *P;
446 FullLibraryPath.appendComponent("lib" + *i);
447 FullLibraryPath.appendSuffix(&(LTDL_SHLIB_EXT[1]));
448 if (!FullLibraryPath.isEmpty()) {
449 if (!FullLibraryPath.isDynamicLibrary()) {
450 // Not a native shared library; mark as invalid
451 FullLibraryPath = sys::Path();
455 if (FullLibraryPath.isEmpty())
456 FullLibraryPath = sys::Path::FindLibrary(*i);
457 if (!FullLibraryPath.isEmpty())
458 Out2 << " -load=" << FullLibraryPath.toString() << " \\\n";
460 Out2 << " $0.bc ${1+\"$@\"}\n";
464 // BuildLinkItems -- This function generates a LinkItemList for the LinkItems
465 // linker function by combining the Files and Libraries in the order they were
466 // declared on the command line.
467 static void BuildLinkItems(
468 Linker::ItemList& Items,
469 const cl::list<std::string>& Files,
470 const cl::list<std::string>& Libraries) {
472 // Build the list of linkage items for LinkItems.
474 cl::list<std::string>::const_iterator fileIt = Files.begin();
475 cl::list<std::string>::const_iterator libIt = Libraries.begin();
477 int libPos = -1, filePos = -1;
478 while ( libIt != Libraries.end() || fileIt != Files.end() ) {
479 if (libIt != Libraries.end())
480 libPos = Libraries.getPosition(libIt - Libraries.begin());
483 if (fileIt != Files.end())
484 filePos = Files.getPosition(fileIt - Files.begin());
488 if (filePos != -1 && (libPos == -1 || filePos < libPos)) {
490 Items.push_back(std::make_pair(*fileIt++, false));
491 } else if (libPos != -1 && (filePos == -1 || libPos < filePos)) {
493 Items.push_back(std::make_pair(*libIt++, true));
498 // Rightly this should go in a header file but it just seems such a waste.
500 extern void Optimize(Module*);
503 int main(int argc, char **argv, char **envp) {
504 llvm_shutdown_obj X; // Call llvm_shutdown() on exit.
506 // Initial global variable above for convenience printing of program name.
507 progname = sys::Path(argv[0]).getBasename();
509 // Parse the command line options
510 cl::ParseCommandLineOptions(argc, argv, "llvm linker\n");
511 sys::PrintStackTraceOnErrorSignal();
513 // Construct a Linker (now that Verbose is set)
514 Linker TheLinker(progname, OutputFilename, Verbose);
516 // Keep track of the native link items (versus the bitcode items)
517 Linker::ItemList NativeLinkItems;
519 // Add library paths to the linker
520 TheLinker.addPaths(LibPaths);
521 TheLinker.addSystemPaths();
523 // Remove any consecutive duplicates of the same library...
524 Libraries.erase(std::unique(Libraries.begin(), Libraries.end()),
528 std::vector<sys::Path> Files;
529 for (unsigned i = 0; i < InputFilenames.size(); ++i )
530 Files.push_back(sys::Path(InputFilenames[i]));
531 if (TheLinker.LinkInFiles(Files))
532 return 1; // Error already printed
534 // The libraries aren't linked in but are noted as "dependent" in the
536 for (cl::list<std::string>::const_iterator I = Libraries.begin(),
537 E = Libraries.end(); I != E ; ++I) {
538 TheLinker.getModule()->addLibrary(*I);
541 // Build a list of the items from our command line
542 Linker::ItemList Items;
543 BuildLinkItems(Items, InputFilenames, Libraries);
545 // Link all the items together
546 if (TheLinker.LinkInItems(Items, NativeLinkItems) )
547 return 1; // Error already printed
550 std::auto_ptr<Module> Composite(TheLinker.releaseModule());
552 // Optimize the module
553 Optimize(Composite.get());
555 #if defined(_WIN32) || defined(__CYGWIN__)
556 if (!LinkAsLibrary) {
557 // Default to "a.exe" instead of "a.out".
558 if (OutputFilename.getNumOccurrences() == 0)
559 OutputFilename = "a.exe";
561 // If there is no suffix add an "exe" one.
562 sys::Path ExeFile( OutputFilename );
563 if (ExeFile.getSuffix() == "") {
564 ExeFile.appendSuffix("exe");
565 OutputFilename = ExeFile.toString();
570 // Generate the bitcode for the optimized module.
571 std::string RealBitcodeOutput = OutputFilename;
573 if (!LinkAsLibrary) RealBitcodeOutput += ".bc";
574 GenerateBitcode(Composite.get(), RealBitcodeOutput);
576 // If we are not linking a library, generate either a native executable
577 // or a JIT shell script, depending upon what the user wants.
578 if (!LinkAsLibrary) {
579 // If the user wants to run a post-link optimization, run it now.
580 if (!PostLinkOpts.empty()) {
581 std::vector<std::string> opts = PostLinkOpts;
582 for (std::vector<std::string>::iterator I = opts.begin(),
583 E = opts.end(); I != E; ++I) {
585 if (!prog.canExecute()) {
586 prog = sys::Program::FindProgramByName(*I);
588 PrintAndExit(std::string("Optimization program '") + *I +
589 "' is not found or not executable.");
591 // Get the program arguments
592 sys::Path tmp_output("opt_result");
594 if (tmp_output.createTemporaryFileOnDisk(true, &ErrMsg))
595 PrintAndExit(ErrMsg);
598 args[0] = I->c_str();
599 args[1] = RealBitcodeOutput.c_str();
600 args[2] = tmp_output.c_str();
602 if (0 == sys::Program::ExecuteAndWait(prog, args, 0,0,0,0, &ErrMsg)) {
603 if (tmp_output.isBitcodeFile() || tmp_output.isBitcodeFile()) {
604 sys::Path target(RealBitcodeOutput);
605 target.eraseFromDisk();
606 if (tmp_output.renamePathOnDisk(target, &ErrMsg))
607 PrintAndExit(ErrMsg, 2);
609 PrintAndExit("Post-link optimization output is not bitcode");
611 PrintAndExit(ErrMsg);
616 // If the user wants to generate a native executable, compile it from the
619 // Otherwise, create a script that will run the bitcode through the JIT.
621 // Name of the Assembly Language output file
622 sys::Path AssemblyFile ( OutputFilename);
623 AssemblyFile.appendSuffix("s");
625 // Mark the output files for removal if we get an interrupt.
626 sys::RemoveFileOnSignal(AssemblyFile);
627 sys::RemoveFileOnSignal(sys::Path(OutputFilename));
629 // Determine the locations of the llc and gcc programs.
630 sys::Path llc = FindExecutable("llc", argv[0]);
632 PrintAndExit("Failed to find llc");
634 sys::Path gcc = FindExecutable("gcc", argv[0]);
636 PrintAndExit("Failed to find gcc");
638 // Generate an assembly language file for the bitcode.
640 if (0 != GenerateAssembly(AssemblyFile.toString(), RealBitcodeOutput,
642 PrintAndExit(ErrMsg);
644 if (0 != GenerateNative(OutputFilename, AssemblyFile.toString(),
645 NativeLinkItems, gcc, envp, ErrMsg))
646 PrintAndExit(ErrMsg);
648 // Remove the assembly language file.
649 AssemblyFile.eraseFromDisk();
650 } else if (NativeCBE) {
651 sys::Path CFile (OutputFilename);
652 CFile.appendSuffix("cbe.c");
654 // Mark the output files for removal if we get an interrupt.
655 sys::RemoveFileOnSignal(CFile);
656 sys::RemoveFileOnSignal(sys::Path(OutputFilename));
658 // Determine the locations of the llc and gcc programs.
659 sys::Path llc = FindExecutable("llc", argv[0]);
661 PrintAndExit("Failed to find llc");
663 sys::Path gcc = FindExecutable("gcc", argv[0]);
665 PrintAndExit("Failed to find gcc");
667 // Generate an assembly language file for the bitcode.
669 if (0 != GenerateCFile(
670 CFile.toString(), RealBitcodeOutput, llc, ErrMsg))
671 PrintAndExit(ErrMsg);
673 if (0 != GenerateNative(OutputFilename, CFile.toString(),
674 NativeLinkItems, gcc, envp, ErrMsg))
675 PrintAndExit(ErrMsg);
677 // Remove the assembly language file.
678 CFile.eraseFromDisk();
681 EmitShellScript(argv);
684 // Make the script executable...
686 if (sys::Path(OutputFilename).makeExecutableOnDisk(&ErrMsg))
687 PrintAndExit(ErrMsg);
689 // Make the bitcode file readable and directly executable in LLEE as well
690 if (sys::Path(RealBitcodeOutput).makeExecutableOnDisk(&ErrMsg))
691 PrintAndExit(ErrMsg);
693 if (sys::Path(RealBitcodeOutput).makeReadableOnDisk(&ErrMsg))
694 PrintAndExit(ErrMsg);
696 } catch (const std::string& msg) {
699 PrintAndExit("Unexpected unknown exception occurred.", 2);