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> FrameworkPaths("F", cl::Prefix,
59 cl::desc("Specify a framework search path"),
60 cl::value_desc("directory"));
62 static cl::list<std::string> Libraries("l", cl::Prefix,
63 cl::desc("Specify libraries to link to"),
64 cl::value_desc("library prefix"));
66 static cl::list<std::string> Frameworks("framework",
67 cl::desc("Specify frameworks to link to"),
68 cl::value_desc("framework"));
70 // Options to control the linking, optimization, and code gen processes
71 static cl::opt<bool> LinkAsLibrary("link-as-library",
72 cl::desc("Link the .bc files together as a library, not an executable"));
74 static cl::alias Relink("r", cl::aliasopt(LinkAsLibrary),
75 cl::desc("Alias for -link-as-library"));
77 static cl::opt<bool> Native("native",
78 cl::desc("Generate a native binary instead of a shell script"));
80 static cl::opt<bool>NativeCBE("native-cbe",
81 cl::desc("Generate a native binary with the C backend and GCC"));
83 static cl::list<std::string> PostLinkOpts("post-link-opts",
84 cl::value_desc("path"),
85 cl::desc("Run one or more optimization programs after linking"));
87 static cl::list<std::string> XLinker("Xlinker", cl::value_desc("option"),
88 cl::desc("Pass options to the system linker"));
90 // Compatibility options that llvm-ld ignores but are supported for
91 // compatibility with LD
92 static cl::opt<std::string> CO3("soname", cl::Hidden,
93 cl::desc("Compatibility option: ignored"));
95 static cl::opt<std::string> CO4("version-script", cl::Hidden,
96 cl::desc("Compatibility option: ignored"));
98 static cl::opt<bool> CO5("eh-frame-hdr", cl::Hidden,
99 cl::desc("Compatibility option: ignored"));
101 static cl::opt<std::string> CO6("h", cl::Hidden,
102 cl::desc("Compatibility option: ignored"));
104 static cl::opt<bool> CO7("start-group", cl::Hidden,
105 cl::desc("Compatibility option: ignored"));
107 static cl::opt<bool> CO8("end-group", cl::Hidden,
108 cl::desc("Compatibility option: ignored"));
110 /// This is just for convenience so it doesn't have to be passed around
112 static std::string progname;
114 /// PrintAndExit - Prints a message to standard error and exits with error code
117 /// Message - The message to print to standard error.
119 static void PrintAndExit(const std::string &Message, int errcode = 1) {
120 cerr << progname << ": " << Message << "\n";
125 static void PrintCommand(const std::vector<const char*> &args) {
126 std::vector<const char*>::const_iterator I = args.begin(), E = args.end();
129 cout << "'" << *I << "'" << " ";
130 cout << "\n" << std::flush;
133 /// CopyEnv - This function takes an array of environment variables and makes a
134 /// copy of it. This copy can then be manipulated any way the caller likes
135 /// without affecting the process's real environment.
138 /// envp - An array of C strings containing an environment.
141 /// NULL - An error occurred.
143 /// Otherwise, a pointer to a new array of C strings is returned. Every string
144 /// in the array is a duplicate of the one in the original array (i.e. we do
145 /// not copy the char *'s from one array to another).
147 static char ** CopyEnv(char ** const envp) {
148 // Count the number of entries in the old list;
149 unsigned entries; // The number of entries in the old environment list
150 for (entries = 0; envp[entries] != NULL; entries++)
153 // Add one more entry for the NULL pointer that ends the list.
156 // If there are no entries at all, just return NULL.
160 // Allocate a new environment list.
161 char **newenv = new char* [entries];
162 if ((newenv = new char* [entries]) == NULL)
165 // Make a copy of the list. Don't forget the NULL that ends the list.
167 while (envp[entries] != NULL) {
168 newenv[entries] = new char[strlen (envp[entries]) + 1];
169 strcpy (newenv[entries], envp[entries]);
172 newenv[entries] = NULL;
178 /// RemoveEnv - Remove the specified environment variable from the environment
182 /// name - The name of the variable to remove. It cannot be NULL.
183 /// envp - The array of environment variables. It cannot be NULL.
186 /// This is mainly done because functions to remove items from the environment
187 /// are not available across all platforms. In particular, Solaris does not
188 /// seem to have an unsetenv() function or a setenv() function (or they are
189 /// undocumented if they do exist).
191 static void RemoveEnv(const char * name, char ** const envp) {
192 for (unsigned index=0; envp[index] != NULL; index++) {
193 // Find the first equals sign in the array and make it an EOS character.
194 char *p = strchr (envp[index], '=');
200 // Compare the two strings. If they are equal, zap this string.
201 // Otherwise, restore it.
202 if (!strcmp(name, envp[index]))
211 /// GenerateBitcode - generates a bitcode file from the module provided
212 void GenerateBitcode(Module* M, const std::string& FileName) {
215 cout << "Generating Bitcode To " << FileName << '\n';
217 // Create the output file.
218 std::ios::openmode io_mode = std::ios::out | std::ios::trunc |
220 std::ofstream Out(FileName.c_str(), io_mode);
222 PrintAndExit("error opening '" + FileName + "' for writing!");
224 // Ensure that the bitcode file gets removed from the disk if we get a
225 // terminating signal.
226 sys::RemoveFileOnSignal(sys::Path(FileName));
229 WriteBitcodeToFile(M, Out);
231 // Close the bitcode file.
235 /// GenerateAssembly - generates a native assembly language source file from the
236 /// specified bitcode file.
239 /// InputFilename - The name of the input bitcode file.
240 /// OutputFilename - The name of the file to generate.
241 /// llc - The pathname to use for LLC.
242 /// envp - The environment to use when running LLC.
244 /// Return non-zero value on error.
246 static int GenerateAssembly(const std::string &OutputFilename,
247 const std::string &InputFilename,
248 const sys::Path &llc,
249 std::string &ErrMsg ) {
250 // Run LLC to convert the bitcode file into assembly code.
251 std::vector<const char*> args;
252 args.push_back(llc.c_str());
253 args.push_back("-f");
254 args.push_back("-o");
255 args.push_back(OutputFilename.c_str());
256 args.push_back(InputFilename.c_str());
260 cout << "Generating Assembly With: \n";
264 return sys::Program::ExecuteAndWait(llc, &args[0], 0, 0, 0, 0, &ErrMsg);
267 /// GenerateCFile - generates a C source file from the specified bitcode file.
268 static int GenerateCFile(const std::string &OutputFile,
269 const std::string &InputFile,
270 const sys::Path &llc,
271 std::string& ErrMsg) {
272 // Run LLC to convert the bitcode file into C.
273 std::vector<const char*> args;
274 args.push_back(llc.c_str());
275 args.push_back("-march=c");
276 args.push_back("-f");
277 args.push_back("-o");
278 args.push_back(OutputFile.c_str());
279 args.push_back(InputFile.c_str());
283 cout << "Generating C Source With: \n";
287 return sys::Program::ExecuteAndWait(llc, &args[0], 0, 0, 0, 0, &ErrMsg);
290 /// GenerateNative - generates a native object file from the
291 /// specified bitcode file.
294 /// InputFilename - The name of the input bitcode file.
295 /// OutputFilename - The name of the file to generate.
296 /// NativeLinkItems - The native libraries, files, code with which to link
297 /// LibPaths - The list of directories in which to find libraries.
298 /// FrameworksPaths - The list of directories in which to find frameworks.
299 /// Frameworks - The list of frameworks (dynamic libraries)
300 /// gcc - The pathname to use for GGC.
301 /// envp - A copy of the process's current environment.
306 /// Returns non-zero value on error.
308 static int GenerateNative(const std::string &OutputFilename,
309 const std::string &InputFilename,
310 const Linker::ItemList &LinkItems,
311 const sys::Path &gcc, char ** const envp,
312 std::string& ErrMsg) {
313 // Remove these environment variables from the environment of the
314 // programs that we will execute. It appears that GCC sets these
315 // environment variables so that the programs it uses can configure
316 // themselves identically.
318 // However, when we invoke GCC below, we want it to use its normal
319 // configuration. Hence, we must sanitize its environment.
320 char ** clean_env = CopyEnv(envp);
321 if (clean_env == NULL)
323 RemoveEnv("LIBRARY_PATH", clean_env);
324 RemoveEnv("COLLECT_GCC_OPTIONS", clean_env);
325 RemoveEnv("GCC_EXEC_PREFIX", clean_env);
326 RemoveEnv("COMPILER_PATH", clean_env);
327 RemoveEnv("COLLECT_GCC", clean_env);
330 // Run GCC to assemble and link the program into native code.
333 // We can't just assemble and link the file with the system assembler
334 // and linker because we don't know where to put the _start symbol.
335 // GCC mysteriously knows how to do it.
336 std::vector<std::string> args;
337 args.push_back(gcc.c_str());
338 args.push_back("-fno-strict-aliasing");
339 args.push_back("-O3");
340 args.push_back("-o");
341 args.push_back(OutputFilename);
342 args.push_back(InputFilename);
344 // Add in the library and framework paths
345 for (unsigned index = 0; index < LibPaths.size(); index++) {
346 args.push_back("-L" + LibPaths[index]);
348 for (unsigned index = 0; index < FrameworkPaths.size(); index++) {
349 args.push_back("-F" + FrameworkPaths[index]);
352 // Add the requested options
353 for (unsigned index = 0; index < XLinker.size(); index++)
354 args.push_back(XLinker[index]);
356 // Add in the libraries to link.
357 for (unsigned index = 0; index < LinkItems.size(); index++)
358 if (LinkItems[index].first != "crtend") {
359 if (LinkItems[index].second)
360 args.push_back("-l" + LinkItems[index].first);
362 args.push_back(LinkItems[index].first);
365 // Add in frameworks to link.
366 for (unsigned index = 0; index < Frameworks.size(); index++) {
367 args.push_back("-framework");
368 args.push_back(Frameworks[index]);
371 // Now that "args" owns all the std::strings for the arguments, call the c_str
372 // method to get the underlying string array. We do this game so that the
373 // std::string array is guaranteed to outlive the const char* array.
374 std::vector<const char *> Args;
375 for (unsigned i = 0, e = args.size(); i != e; ++i)
376 Args.push_back(args[i].c_str());
380 cout << "Generating Native Executable With:\n";
384 // Run the compiler to assembly and link together the program.
385 int R = sys::Program::ExecuteAndWait(
386 gcc, &Args[0], (const char**)clean_env, 0, 0, 0, &ErrMsg);
391 /// EmitShellScript - Output the wrapper file that invokes the JIT on the LLVM
392 /// bitcode file for the program.
393 static void EmitShellScript(char **argv) {
395 cout << "Emitting Shell Script\n";
396 #if defined(_WIN32) || defined(__CYGWIN__)
397 // Windows doesn't support #!/bin/sh style shell scripts in .exe files. To
398 // support windows systems, we copy the llvm-stub.exe executable from the
399 // build tree to the destination file.
401 sys::Path llvmstub = FindExecutable("llvm-stub.exe", argv[0]);
402 if (llvmstub.isEmpty())
403 PrintAndExit("Could not find llvm-stub.exe executable!");
405 if (0 != sys::CopyFile(sys::Path(OutputFilename), llvmstub, &ErrMsg))
406 PrintAndExit(ErrMsg);
411 // Output the script to start the program...
412 std::ofstream Out2(OutputFilename.c_str());
414 PrintAndExit("error opening '" + OutputFilename + "' for writing!");
416 Out2 << "#!/bin/sh\n";
417 // Allow user to setenv LLVMINTERP if lli is not in their PATH.
418 Out2 << "lli=${LLVMINTERP-lli}\n";
419 Out2 << "exec $lli \\\n";
420 // gcc accepts -l<lib> and implicitly searches /lib and /usr/lib.
421 LibPaths.push_back("/lib");
422 LibPaths.push_back("/usr/lib");
423 LibPaths.push_back("/usr/X11R6/lib");
424 // We don't need to link in libc! In fact, /usr/lib/libc.so may not be a
425 // shared object at all! See RH 8: plain text.
426 std::vector<std::string>::iterator libc =
427 std::find(Libraries.begin(), Libraries.end(), "c");
428 if (libc != Libraries.end()) Libraries.erase(libc);
429 // List all the shared object (native) libraries this executable will need
430 // on the command line, so that we don't have to do this manually!
431 for (std::vector<std::string>::iterator i = Libraries.begin(),
432 e = Libraries.end(); i != e; ++i) {
433 sys::Path FullLibraryPath = sys::Path::FindLibrary(*i);
434 if (!FullLibraryPath.isEmpty() && FullLibraryPath.isDynamicLibrary())
435 Out2 << " -load=" << FullLibraryPath.toString() << " \\\n";
437 Out2 << " $0.bc ${1+\"$@\"}\n";
441 // BuildLinkItems -- This function generates a LinkItemList for the LinkItems
442 // linker function by combining the Files and Libraries in the order they were
443 // declared on the command line.
444 static void BuildLinkItems(
445 Linker::ItemList& Items,
446 const cl::list<std::string>& Files,
447 const cl::list<std::string>& Libraries) {
449 // Build the list of linkage items for LinkItems.
451 cl::list<std::string>::const_iterator fileIt = Files.begin();
452 cl::list<std::string>::const_iterator libIt = Libraries.begin();
454 int libPos = -1, filePos = -1;
455 while ( libIt != Libraries.end() || fileIt != Files.end() ) {
456 if (libIt != Libraries.end())
457 libPos = Libraries.getPosition(libIt - Libraries.begin());
460 if (fileIt != Files.end())
461 filePos = Files.getPosition(fileIt - Files.begin());
465 if (filePos != -1 && (libPos == -1 || filePos < libPos)) {
467 Items.push_back(std::make_pair(*fileIt++, false));
468 } else if (libPos != -1 && (filePos == -1 || libPos < filePos)) {
470 Items.push_back(std::make_pair(*libIt++, true));
475 // Rightly this should go in a header file but it just seems such a waste.
477 extern void Optimize(Module*);
480 int main(int argc, char **argv, char **envp) {
481 llvm_shutdown_obj X; // Call llvm_shutdown() on exit.
483 // Initial global variable above for convenience printing of program name.
484 progname = sys::Path(argv[0]).getBasename();
486 // Parse the command line options
487 cl::ParseCommandLineOptions(argc, argv, "llvm linker\n");
488 sys::PrintStackTraceOnErrorSignal();
490 // Construct a Linker (now that Verbose is set)
491 Linker TheLinker(progname, OutputFilename, Verbose);
493 // Keep track of the native link items (versus the bitcode items)
494 Linker::ItemList NativeLinkItems;
496 // Add library paths to the linker
497 TheLinker.addPaths(LibPaths);
498 TheLinker.addSystemPaths();
500 // Remove any consecutive duplicates of the same library...
501 Libraries.erase(std::unique(Libraries.begin(), Libraries.end()),
505 std::vector<sys::Path> Files;
506 for (unsigned i = 0; i < InputFilenames.size(); ++i )
507 Files.push_back(sys::Path(InputFilenames[i]));
508 if (TheLinker.LinkInFiles(Files))
509 return 1; // Error already printed
511 // The libraries aren't linked in but are noted as "dependent" in the
513 for (cl::list<std::string>::const_iterator I = Libraries.begin(),
514 E = Libraries.end(); I != E ; ++I) {
515 TheLinker.getModule()->addLibrary(*I);
518 // Build a list of the items from our command line
519 Linker::ItemList Items;
520 BuildLinkItems(Items, InputFilenames, Libraries);
522 // Link all the items together
523 if (TheLinker.LinkInItems(Items, NativeLinkItems) )
524 return 1; // Error already printed
527 std::auto_ptr<Module> Composite(TheLinker.releaseModule());
529 // Optimize the module
530 Optimize(Composite.get());
532 // Generate the bitcode for the optimized module.
533 std::string RealBitcodeOutput = OutputFilename;
534 if (!LinkAsLibrary) RealBitcodeOutput += ".bc";
535 GenerateBitcode(Composite.get(), RealBitcodeOutput);
537 // If we are not linking a library, generate either a native executable
538 // or a JIT shell script, depending upon what the user wants.
539 if (!LinkAsLibrary) {
540 // If the user wants to run a post-link optimization, run it now.
541 if (!PostLinkOpts.empty()) {
542 std::vector<std::string> opts = PostLinkOpts;
543 for (std::vector<std::string>::iterator I = opts.begin(),
544 E = opts.end(); I != E; ++I) {
546 if (!prog.canExecute()) {
547 prog = sys::Program::FindProgramByName(*I);
549 PrintAndExit(std::string("Optimization program '") + *I +
550 "' is not found or not executable.");
552 // Get the program arguments
553 sys::Path tmp_output("opt_result");
555 if (tmp_output.createTemporaryFileOnDisk(true, &ErrMsg))
556 PrintAndExit(ErrMsg);
559 args[0] = I->c_str();
560 args[1] = RealBitcodeOutput.c_str();
561 args[2] = tmp_output.c_str();
563 if (0 == sys::Program::ExecuteAndWait(prog, args, 0,0,0,0, &ErrMsg)) {
564 if (tmp_output.isBitcodeFile() || tmp_output.isBitcodeFile()) {
565 sys::Path target(RealBitcodeOutput);
566 target.eraseFromDisk();
567 if (tmp_output.renamePathOnDisk(target, &ErrMsg))
568 PrintAndExit(ErrMsg, 2);
570 PrintAndExit("Post-link optimization output is not bitcode");
572 PrintAndExit(ErrMsg);
577 // If the user wants to generate a native executable, compile it from the
580 // Otherwise, create a script that will run the bitcode through the JIT.
582 // Name of the Assembly Language output file
583 sys::Path AssemblyFile ( OutputFilename);
584 AssemblyFile.appendSuffix("s");
586 // Mark the output files for removal if we get an interrupt.
587 sys::RemoveFileOnSignal(AssemblyFile);
588 sys::RemoveFileOnSignal(sys::Path(OutputFilename));
590 // Determine the locations of the llc and gcc programs.
591 sys::Path llc = FindExecutable("llc", argv[0]);
593 PrintAndExit("Failed to find llc");
595 sys::Path gcc = FindExecutable("gcc", argv[0]);
597 PrintAndExit("Failed to find gcc");
599 // Generate an assembly language file for the bitcode.
601 if (0 != GenerateAssembly(AssemblyFile.toString(), RealBitcodeOutput,
603 PrintAndExit(ErrMsg);
605 if (0 != GenerateNative(OutputFilename, AssemblyFile.toString(),
606 NativeLinkItems, gcc, envp, ErrMsg))
607 PrintAndExit(ErrMsg);
609 // Remove the assembly language file.
610 AssemblyFile.eraseFromDisk();
611 } else if (NativeCBE) {
612 sys::Path CFile (OutputFilename);
613 CFile.appendSuffix("cbe.c");
615 // Mark the output files for removal if we get an interrupt.
616 sys::RemoveFileOnSignal(CFile);
617 sys::RemoveFileOnSignal(sys::Path(OutputFilename));
619 // Determine the locations of the llc and gcc programs.
620 sys::Path llc = FindExecutable("llc", argv[0]);
622 PrintAndExit("Failed to find llc");
624 sys::Path gcc = FindExecutable("gcc", argv[0]);
626 PrintAndExit("Failed to find gcc");
628 // Generate an assembly language file for the bitcode.
630 if (0 != GenerateCFile(
631 CFile.toString(), RealBitcodeOutput, llc, ErrMsg))
632 PrintAndExit(ErrMsg);
634 if (0 != GenerateNative(OutputFilename, CFile.toString(),
635 NativeLinkItems, gcc, envp, ErrMsg))
636 PrintAndExit(ErrMsg);
638 // Remove the assembly language file.
639 CFile.eraseFromDisk();
642 EmitShellScript(argv);
645 // Make the script executable...
647 if (sys::Path(OutputFilename).makeExecutableOnDisk(&ErrMsg))
648 PrintAndExit(ErrMsg);
650 // Make the bitcode file readable and directly executable in LLEE as well
651 if (sys::Path(RealBitcodeOutput).makeExecutableOnDisk(&ErrMsg))
652 PrintAndExit(ErrMsg);
654 if (sys::Path(RealBitcodeOutput).makeReadableOnDisk(&ErrMsg))
655 PrintAndExit(ErrMsg);
657 } catch (const std::string& msg) {
660 PrintAndExit("Unexpected unknown exception occurred.", 2);