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"
43 // Input/Output Options
44 static cl::list<std::string> InputFilenames(cl::Positional, cl::OneOrMore,
45 cl::desc("<input bitcode files>"));
47 static cl::opt<std::string> OutputFilename("o", cl::init("a.out"),
48 cl::desc("Override output filename"),
49 cl::value_desc("filename"));
51 static cl::opt<bool> Verbose("v",
52 cl::desc("Print information about actions taken"));
54 static cl::list<std::string> LibPaths("L", cl::Prefix,
55 cl::desc("Specify a library search path"),
56 cl::value_desc("directory"));
58 static cl::list<std::string> Libraries("l", cl::Prefix,
59 cl::desc("Specify libraries to link to"),
60 cl::value_desc("library prefix"));
62 // Options to control the linking, optimization, and code gen processes
63 static cl::opt<bool> LinkAsLibrary("link-as-library",
64 cl::desc("Link the .bc files together as a library, not an executable"));
66 static cl::alias Relink("r", cl::aliasopt(LinkAsLibrary),
67 cl::desc("Alias for -link-as-library"));
69 static cl::opt<bool> Native("native",
70 cl::desc("Generate a native binary instead of a shell script"));
72 static cl::opt<bool>NativeCBE("native-cbe",
73 cl::desc("Generate a native binary with the C backend and GCC"));
75 static cl::list<std::string> PostLinkOpts("post-link-opts",
76 cl::value_desc("path"),
77 cl::desc("Run one or more optimization programs after linking"));
79 static cl::list<std::string> XLinker("Xlinker", cl::value_desc("option"),
80 cl::desc("Pass options to the system linker"));
82 // Compatibility options that llvm-ld ignores but are supported for
83 // compatibility with LD
84 static cl::opt<std::string> CO3("soname", cl::Hidden,
85 cl::desc("Compatibility option: ignored"));
87 static cl::opt<std::string> CO4("version-script", cl::Hidden,
88 cl::desc("Compatibility option: ignored"));
90 static cl::opt<bool> CO5("eh-frame-hdr", cl::Hidden,
91 cl::desc("Compatibility option: ignored"));
93 static cl::opt<std::string> CO6("h", cl::Hidden,
94 cl::desc("Compatibility option: ignored"));
96 static cl::opt<bool> CO7("start-group", cl::Hidden,
97 cl::desc("Compatibility option: ignored"));
99 static cl::opt<bool> CO8("end-group", cl::Hidden,
100 cl::desc("Compatibility option: ignored"));
102 /// This is just for convenience so it doesn't have to be passed around
104 static std::string progname;
106 /// PrintAndExit - Prints a message to standard error and exits with error code
109 /// Message - The message to print to standard error.
111 static void PrintAndExit(const std::string &Message, int errcode = 1) {
112 cerr << progname << ": " << Message << "\n";
117 static void PrintCommand(const std::vector<const char*> &args) {
118 std::vector<const char*>::const_iterator I = args.begin(), E = args.end();
121 cout << "'" << *I << "'" << " ";
122 cout << "\n" << std::flush;
125 /// CopyEnv - This function takes an array of environment variables and makes a
126 /// copy of it. This copy can then be manipulated any way the caller likes
127 /// without affecting the process's real environment.
130 /// envp - An array of C strings containing an environment.
133 /// NULL - An error occurred.
135 /// Otherwise, a pointer to a new array of C strings is returned. Every string
136 /// in the array is a duplicate of the one in the original array (i.e. we do
137 /// not copy the char *'s from one array to another).
139 static char ** CopyEnv(char ** const envp) {
140 // Count the number of entries in the old list;
141 unsigned entries; // The number of entries in the old environment list
142 for (entries = 0; envp[entries] != NULL; entries++)
145 // Add one more entry for the NULL pointer that ends the list.
148 // If there are no entries at all, just return NULL.
152 // Allocate a new environment list.
153 char **newenv = new char* [entries];
154 if ((newenv = new char* [entries]) == NULL)
157 // Make a copy of the list. Don't forget the NULL that ends the list.
159 while (envp[entries] != NULL) {
160 newenv[entries] = new char[strlen (envp[entries]) + 1];
161 strcpy (newenv[entries], envp[entries]);
164 newenv[entries] = NULL;
170 /// RemoveEnv - Remove the specified environment variable from the environment
174 /// name - The name of the variable to remove. It cannot be NULL.
175 /// envp - The array of environment variables. It cannot be NULL.
178 /// This is mainly done because functions to remove items from the environment
179 /// are not available across all platforms. In particular, Solaris does not
180 /// seem to have an unsetenv() function or a setenv() function (or they are
181 /// undocumented if they do exist).
183 static void RemoveEnv(const char * name, char ** const envp) {
184 for (unsigned index=0; envp[index] != NULL; index++) {
185 // Find the first equals sign in the array and make it an EOS character.
186 char *p = strchr (envp[index], '=');
192 // Compare the two strings. If they are equal, zap this string.
193 // Otherwise, restore it.
194 if (!strcmp(name, envp[index]))
203 /// GenerateBitcode - generates a bitcode file from the module provided
204 void GenerateBitcode(Module* M, const std::string& FileName) {
207 cout << "Generating Bitcode To " << FileName << '\n';
209 // Create the output file.
210 std::ios::openmode io_mode = std::ios::out | std::ios::trunc |
212 std::ofstream Out(FileName.c_str(), io_mode);
214 PrintAndExit("error opening '" + FileName + "' for writing!");
216 // Ensure that the bitcode file gets removed from the disk if we get a
217 // terminating signal.
218 sys::RemoveFileOnSignal(sys::Path(FileName));
221 WriteBitcodeToFile(M, Out);
223 // Close the bitcode file.
227 /// GenerateAssembly - generates a native assembly language source file from the
228 /// specified bitcode file.
231 /// InputFilename - The name of the input bitcode file.
232 /// OutputFilename - The name of the file to generate.
233 /// llc - The pathname to use for LLC.
234 /// envp - The environment to use when running LLC.
236 /// Return non-zero value on error.
238 static int GenerateAssembly(const std::string &OutputFilename,
239 const std::string &InputFilename,
240 const sys::Path &llc,
241 std::string &ErrMsg ) {
242 // Run LLC to convert the bitcode file into assembly code.
243 std::vector<const char*> args;
244 args.push_back(llc.c_str());
245 args.push_back("-f");
246 args.push_back("-o");
247 args.push_back(OutputFilename.c_str());
248 args.push_back(InputFilename.c_str());
252 cout << "Generating Assembly With: \n";
256 return sys::Program::ExecuteAndWait(llc, &args[0], 0, 0, 0, 0, &ErrMsg);
259 /// GenerateCFile - generates a C source file from the specified bitcode file.
260 static int GenerateCFile(const std::string &OutputFile,
261 const std::string &InputFile,
262 const sys::Path &llc,
263 std::string& ErrMsg) {
264 // Run LLC to convert the bitcode file into C.
265 std::vector<const char*> args;
266 args.push_back(llc.c_str());
267 args.push_back("-march=c");
268 args.push_back("-f");
269 args.push_back("-o");
270 args.push_back(OutputFile.c_str());
271 args.push_back(InputFile.c_str());
275 cout << "Generating C Source With: \n";
279 return sys::Program::ExecuteAndWait(llc, &args[0], 0, 0, 0, 0, &ErrMsg);
282 /// GenerateNative - generates a native object file from the
283 /// specified bitcode file.
286 /// InputFilename - The name of the input bitcode file.
287 /// OutputFilename - The name of the file to generate.
288 /// NativeLinkItems - The native libraries, files, code with which to link
289 /// LibPaths - The list of directories in which to find libraries.
290 /// gcc - The pathname to use for GGC.
291 /// envp - A copy of the process's current environment.
296 /// Returns non-zero value on error.
298 static int GenerateNative(const std::string &OutputFilename,
299 const std::string &InputFilename,
300 const Linker::ItemList &LinkItems,
301 const sys::Path &gcc, char ** const envp,
302 std::string& ErrMsg) {
303 // Remove these environment variables from the environment of the
304 // programs that we will execute. It appears that GCC sets these
305 // environment variables so that the programs it uses can configure
306 // themselves identically.
308 // However, when we invoke GCC below, we want it to use its normal
309 // configuration. Hence, we must sanitize its environment.
310 char ** clean_env = CopyEnv(envp);
311 if (clean_env == NULL)
313 RemoveEnv("LIBRARY_PATH", clean_env);
314 RemoveEnv("COLLECT_GCC_OPTIONS", clean_env);
315 RemoveEnv("GCC_EXEC_PREFIX", clean_env);
316 RemoveEnv("COMPILER_PATH", clean_env);
317 RemoveEnv("COLLECT_GCC", clean_env);
320 // Run GCC to assemble and link the program into native code.
323 // We can't just assemble and link the file with the system assembler
324 // and linker because we don't know where to put the _start symbol.
325 // GCC mysteriously knows how to do it.
326 std::vector<std::string> args;
327 args.push_back(gcc.c_str());
328 args.push_back("-fno-strict-aliasing");
329 args.push_back("-O3");
330 args.push_back("-o");
331 args.push_back(OutputFilename);
332 args.push_back(InputFilename);
334 // Add in the library paths
335 for (unsigned index = 0; index < LibPaths.size(); index++) {
336 args.push_back("-L");
337 args.push_back(LibPaths[index]);
340 // Add the requested options
341 for (unsigned index = 0; index < XLinker.size(); index++) {
342 args.push_back(XLinker[index]);
343 args.push_back(Libraries[index]);
346 // Add in the libraries to link.
347 for (unsigned index = 0; index < LinkItems.size(); index++)
348 if (LinkItems[index].first != "crtend") {
349 if (LinkItems[index].second)
350 args.push_back("-l" + LinkItems[index].first);
352 args.push_back(LinkItems[index].first);
356 // Now that "args" owns all the std::strings for the arguments, call the c_str
357 // method to get the underlying string array. We do this game so that the
358 // std::string array is guaranteed to outlive the const char* array.
359 std::vector<const char *> Args;
360 for (unsigned i = 0, e = args.size(); i != e; ++i)
361 Args.push_back(args[i].c_str());
365 cout << "Generating Native Executable With:\n";
369 // Run the compiler to assembly and link together the program.
370 int R = sys::Program::ExecuteAndWait(
371 gcc, &Args[0], (const char**)clean_env, 0, 0, 0, &ErrMsg);
376 /// EmitShellScript - Output the wrapper file that invokes the JIT on the LLVM
377 /// bitcode file for the program.
378 static void EmitShellScript(char **argv) {
380 cout << "Emitting Shell Script\n";
381 #if defined(_WIN32) || defined(__CYGWIN__)
382 // Windows doesn't support #!/bin/sh style shell scripts in .exe files. To
383 // support windows systems, we copy the llvm-stub.exe executable from the
384 // build tree to the destination file.
386 sys::Path llvmstub = FindExecutable("llvm-stub.exe", argv[0]);
387 if (llvmstub.isEmpty())
388 PrintAndExit("Could not find llvm-stub.exe executable!");
390 if (0 != sys::CopyFile(sys::Path(OutputFilename), llvmstub, &ErrMsg))
391 PrintAndExit(ErrMsg);
396 // Output the script to start the program...
397 std::ofstream Out2(OutputFilename.c_str());
399 PrintAndExit("error opening '" + OutputFilename + "' for writing!");
401 Out2 << "#!/bin/sh\n";
402 // Allow user to setenv LLVMINTERP if lli is not in their PATH.
403 Out2 << "lli=${LLVMINTERP-lli}\n";
404 Out2 << "exec $lli \\\n";
405 // gcc accepts -l<lib> and implicitly searches /lib and /usr/lib.
406 LibPaths.push_back("/lib");
407 LibPaths.push_back("/usr/lib");
408 LibPaths.push_back("/usr/X11R6/lib");
409 // We don't need to link in libc! In fact, /usr/lib/libc.so may not be a
410 // shared object at all! See RH 8: plain text.
411 std::vector<std::string>::iterator libc =
412 std::find(Libraries.begin(), Libraries.end(), "c");
413 if (libc != Libraries.end()) Libraries.erase(libc);
414 // List all the shared object (native) libraries this executable will need
415 // on the command line, so that we don't have to do this manually!
416 for (std::vector<std::string>::iterator i = Libraries.begin(),
417 e = Libraries.end(); i != e; ++i) {
418 sys::Path FullLibraryPath = sys::Path::FindLibrary(*i);
419 if (!FullLibraryPath.isEmpty() && FullLibraryPath.isDynamicLibrary())
420 Out2 << " -load=" << FullLibraryPath.toString() << " \\\n";
422 Out2 << " $0.bc ${1+\"$@\"}\n";
426 // BuildLinkItems -- This function generates a LinkItemList for the LinkItems
427 // linker function by combining the Files and Libraries in the order they were
428 // declared on the command line.
429 static void BuildLinkItems(
430 Linker::ItemList& Items,
431 const cl::list<std::string>& Files,
432 const cl::list<std::string>& Libraries) {
434 // Build the list of linkage items for LinkItems.
436 cl::list<std::string>::const_iterator fileIt = Files.begin();
437 cl::list<std::string>::const_iterator libIt = Libraries.begin();
439 int libPos = -1, filePos = -1;
440 while ( libIt != Libraries.end() || fileIt != Files.end() ) {
441 if (libIt != Libraries.end())
442 libPos = Libraries.getPosition(libIt - Libraries.begin());
445 if (fileIt != Files.end())
446 filePos = Files.getPosition(fileIt - Files.begin());
450 if (filePos != -1 && (libPos == -1 || filePos < libPos)) {
452 Items.push_back(std::make_pair(*fileIt++, false));
453 } else if (libPos != -1 && (filePos == -1 || libPos < filePos)) {
455 Items.push_back(std::make_pair(*libIt++, true));
460 // Rightly this should go in a header file but it just seems such a waste.
462 extern void Optimize(Module*);
465 int main(int argc, char **argv, char **envp) {
466 llvm_shutdown_obj X; // Call llvm_shutdown() on exit.
468 // Initial global variable above for convenience printing of program name.
469 progname = sys::Path(argv[0]).getBasename();
471 // Parse the command line options
472 cl::ParseCommandLineOptions(argc, argv, "llvm linker\n");
473 sys::PrintStackTraceOnErrorSignal();
475 // Construct a Linker (now that Verbose is set)
476 Linker TheLinker(progname, OutputFilename, Verbose);
478 // Keep track of the native link items (versus the bitcode items)
479 Linker::ItemList NativeLinkItems;
481 // Add library paths to the linker
482 TheLinker.addPaths(LibPaths);
483 TheLinker.addSystemPaths();
485 // Remove any consecutive duplicates of the same library...
486 Libraries.erase(std::unique(Libraries.begin(), Libraries.end()),
490 std::vector<sys::Path> Files;
491 for (unsigned i = 0; i < InputFilenames.size(); ++i )
492 Files.push_back(sys::Path(InputFilenames[i]));
493 if (TheLinker.LinkInFiles(Files))
494 return 1; // Error already printed
496 // The libraries aren't linked in but are noted as "dependent" in the
498 for (cl::list<std::string>::const_iterator I = Libraries.begin(),
499 E = Libraries.end(); I != E ; ++I) {
500 TheLinker.getModule()->addLibrary(*I);
503 // Build a list of the items from our command line
504 Linker::ItemList Items;
505 BuildLinkItems(Items, InputFilenames, Libraries);
507 // Link all the items together
508 if (TheLinker.LinkInItems(Items, NativeLinkItems) )
509 return 1; // Error already printed
512 std::auto_ptr<Module> Composite(TheLinker.releaseModule());
514 // Optimize the module
515 Optimize(Composite.get());
517 // Generate the bitcode for the optimized module.
518 std::string RealBitcodeOutput = OutputFilename;
519 if (!LinkAsLibrary) RealBitcodeOutput += ".bc";
520 GenerateBitcode(Composite.get(), RealBitcodeOutput);
522 // If we are not linking a library, generate either a native executable
523 // or a JIT shell script, depending upon what the user wants.
524 if (!LinkAsLibrary) {
525 // If the user wants to run a post-link optimization, run it now.
526 if (!PostLinkOpts.empty()) {
527 std::vector<std::string> opts = PostLinkOpts;
528 for (std::vector<std::string>::iterator I = opts.begin(),
529 E = opts.end(); I != E; ++I) {
531 if (!prog.canExecute()) {
532 prog = sys::Program::FindProgramByName(*I);
534 PrintAndExit(std::string("Optimization program '") + *I +
535 "' is not found or not executable.");
537 // Get the program arguments
538 sys::Path tmp_output("opt_result");
540 if (tmp_output.createTemporaryFileOnDisk(true, &ErrMsg))
541 PrintAndExit(ErrMsg);
544 args[0] = I->c_str();
545 args[1] = RealBitcodeOutput.c_str();
546 args[2] = tmp_output.c_str();
548 if (0 == sys::Program::ExecuteAndWait(prog, args, 0,0,0,0, &ErrMsg)) {
549 if (tmp_output.isBitcodeFile() || tmp_output.isBitcodeFile()) {
550 sys::Path target(RealBitcodeOutput);
551 target.eraseFromDisk();
552 if (tmp_output.renamePathOnDisk(target, &ErrMsg))
553 PrintAndExit(ErrMsg, 2);
555 PrintAndExit("Post-link optimization output is not bitcode");
557 PrintAndExit(ErrMsg);
562 // If the user wants to generate a native executable, compile it from the
565 // Otherwise, create a script that will run the bitcode through the JIT.
567 // Name of the Assembly Language output file
568 sys::Path AssemblyFile ( OutputFilename);
569 AssemblyFile.appendSuffix("s");
571 // Mark the output files for removal if we get an interrupt.
572 sys::RemoveFileOnSignal(AssemblyFile);
573 sys::RemoveFileOnSignal(sys::Path(OutputFilename));
575 // Determine the locations of the llc and gcc programs.
576 sys::Path llc = FindExecutable("llc", argv[0]);
578 PrintAndExit("Failed to find llc");
580 sys::Path gcc = FindExecutable("gcc", argv[0]);
582 PrintAndExit("Failed to find gcc");
584 // Generate an assembly language file for the bitcode.
586 if (0 != GenerateAssembly(AssemblyFile.toString(), RealBitcodeOutput,
588 PrintAndExit(ErrMsg);
590 if (0 != GenerateNative(OutputFilename, AssemblyFile.toString(),
591 NativeLinkItems, gcc, envp, ErrMsg))
592 PrintAndExit(ErrMsg);
594 // Remove the assembly language file.
595 AssemblyFile.eraseFromDisk();
596 } else if (NativeCBE) {
597 sys::Path CFile (OutputFilename);
598 CFile.appendSuffix("cbe.c");
600 // Mark the output files for removal if we get an interrupt.
601 sys::RemoveFileOnSignal(CFile);
602 sys::RemoveFileOnSignal(sys::Path(OutputFilename));
604 // Determine the locations of the llc and gcc programs.
605 sys::Path llc = FindExecutable("llc", argv[0]);
607 PrintAndExit("Failed to find llc");
609 sys::Path gcc = FindExecutable("gcc", argv[0]);
611 PrintAndExit("Failed to find gcc");
613 // Generate an assembly language file for the bitcode.
615 if (0 != GenerateCFile(
616 CFile.toString(), RealBitcodeOutput, llc, ErrMsg))
617 PrintAndExit(ErrMsg);
619 if (0 != GenerateNative(OutputFilename, CFile.toString(),
620 NativeLinkItems, gcc, envp, ErrMsg))
621 PrintAndExit(ErrMsg);
623 // Remove the assembly language file.
624 CFile.eraseFromDisk();
627 EmitShellScript(argv);
630 // Make the script executable...
632 if (sys::Path(OutputFilename).makeExecutableOnDisk(&ErrMsg))
633 PrintAndExit(ErrMsg);
635 // Make the bitcode file readable and directly executable in LLEE as well
636 if (sys::Path(RealBitcodeOutput).makeExecutableOnDisk(&ErrMsg))
637 PrintAndExit(ErrMsg);
639 if (sys::Path(RealBitcodeOutput).makeReadableOnDisk(&ErrMsg))
640 PrintAndExit(ErrMsg);
642 } catch (const std::string& msg) {
645 PrintAndExit("Unexpected unknown exception occurred.", 2);