tools/llvm-ld/llvm-ld.cpp

   1 //===- llvm-ld.cpp - LLVM 'ld' compatible linker --------------------------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  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.
  16 //
  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.
  20 //
  21 //===----------------------------------------------------------------------===//
  22
  23 #include "llvm/LinkAllVMCore.h"
  24 #include "llvm/Linker.h"
  25 #include "llvm/LLVMContext.h"
  26 #include "llvm/System/Program.h"
  27 #include "llvm/Module.h"
  28 #include "llvm/PassManager.h"
  29 #include "llvm/Bitcode/ReaderWriter.h"
  30 #include "llvm/Target/TargetData.h"
  31 #include "llvm/Target/TargetMachine.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/PrettyStackTrace.h"
  37 #include "llvm/Support/SystemUtils.h"
  38 #include "llvm/Support/raw_ostream.h"
  39 #include "llvm/System/Signals.h"
  40 #include "llvm/Config/config.h"
  41 #include <memory>
  42 #include <cstring>
  43 using namespace llvm;
  44
  45 // Rightly this should go in a header file but it just seems such a waste.
  46 namespace llvm {
  47 extern void Optimize(Module*);
  48 }
  49
  50 // Input/Output Options
  51 static cl::list<std::string> InputFilenames(cl::Positional, cl::OneOrMore,
  52   cl::desc("<input bitcode files>"));
  53
  54 static cl::opt<std::string> OutputFilename("o", cl::init("a.out"),
  55   cl::desc("Override output filename"),
  56   cl::value_desc("filename"));
  57
  58 static cl::opt<std::string> BitcodeOutputFilename("b", cl::init(""),
  59   cl::desc("Override bitcode output filename"),
  60   cl::value_desc("filename"));
  61
  62 static cl::opt<bool> Verbose("v",
  63   cl::desc("Print information about actions taken"));
  64
  65 static cl::list<std::string> LibPaths("L", cl::Prefix,
  66   cl::desc("Specify a library search path"),
  67   cl::value_desc("directory"));
  68
  69 static cl::list<std::string> FrameworkPaths("F", cl::Prefix,
  70   cl::desc("Specify a framework search path"),
  71   cl::value_desc("directory"));
  72
  73 static cl::list<std::string> Libraries("l", cl::Prefix,
  74   cl::desc("Specify libraries to link to"),
  75   cl::value_desc("library prefix"));
  76
  77 static cl::list<std::string> Frameworks("framework",
  78   cl::desc("Specify frameworks to link to"),
  79   cl::value_desc("framework"));
  80
  81 // Options to control the linking, optimization, and code gen processes
  82 static cl::opt<bool> LinkAsLibrary("link-as-library",
  83   cl::desc("Link the .bc files together as a library, not an executable"));
  84
  85 static cl::alias Relink("r", cl::aliasopt(LinkAsLibrary),
  86   cl::desc("Alias for -link-as-library"));
  87
  88 static cl::opt<bool> Native("native",
  89   cl::desc("Generate a native binary instead of a shell script"));
  90
  91 static cl::opt<bool>NativeCBE("native-cbe",
  92   cl::desc("Generate a native binary with the C backend and GCC"));
  93
  94 static cl::list<std::string> PostLinkOpts("post-link-opts",
  95   cl::value_desc("path"),
  96   cl::desc("Run one or more optimization programs after linking"));
  97
  98 static cl::list<std::string> XLinker("Xlinker", cl::value_desc("option"),
  99   cl::desc("Pass options to the system linker"));
 100
 101 // Compatibility options that llvm-ld ignores but are supported for
 102 // compatibility with LD
 103 static cl::opt<std::string> CO3("soname", cl::Hidden,
 104   cl::desc("Compatibility option: ignored"));
 105
 106 static cl::opt<std::string> CO4("version-script", cl::Hidden,
 107   cl::desc("Compatibility option: ignored"));
 108
 109 static cl::opt<bool> CO5("eh-frame-hdr", cl::Hidden,
 110   cl::desc("Compatibility option: ignored"));
 111
 112 static  cl::opt<std::string> CO6("h", cl::Hidden,
 113   cl::desc("Compatibility option: ignored"));
 114
 115 static cl::opt<bool> CO7("start-group", cl::Hidden,
 116   cl::desc("Compatibility option: ignored"));
 117
 118 static cl::opt<bool> CO8("end-group", cl::Hidden,
 119   cl::desc("Compatibility option: ignored"));
 120
 121 static cl::opt<std::string> CO9("m", cl::Hidden,
 122   cl::desc("Compatibility option: ignored"));
 123
 124 /// This is just for convenience so it doesn't have to be passed around
 125 /// everywhere.
 126 static std::string progname;
 127
 128 /// PrintAndExit - Prints a message to standard error and exits with error code
 129 ///
 130 /// Inputs:
 131 ///  Message  - The message to print to standard error.
 132 ///
 133 static void PrintAndExit(const std::string &Message, int errcode = 1) {
 134   errs() << progname << ": " << Message << "\n";
 135   llvm_shutdown();
 136   exit(errcode);
 137 }
 138
 139 static void PrintCommand(const std::vector<const char*> &args) {
 140   std::vector<const char*>::const_iterator I = args.begin(), E = args.end();
 141   for (; I != E; ++I)
 142     if (*I)
 143       outs() << "'" << *I << "'" << " ";
 144   outs() << "\n"; outs().flush();
 145 }
 146
 147 /// CopyEnv - This function takes an array of environment variables and makes a
 148 /// copy of it.  This copy can then be manipulated any way the caller likes
 149 /// without affecting the process's real environment.
 150 ///
 151 /// Inputs:
 152 ///  envp - An array of C strings containing an environment.
 153 ///
 154 /// Return value:
 155 ///  NULL - An error occurred.
 156 ///
 157 ///  Otherwise, a pointer to a new array of C strings is returned.  Every string
 158 ///  in the array is a duplicate of the one in the original array (i.e. we do
 159 ///  not copy the char *'s from one array to another).
 160 ///
 161 static char ** CopyEnv(char ** const envp) {
 162   // Count the number of entries in the old list;
 163   unsigned entries;   // The number of entries in the old environment list
 164   for (entries = 0; envp[entries] != NULL; entries++)
 165     /*empty*/;
 166
 167   // Add one more entry for the NULL pointer that ends the list.
 168   ++entries;
 169
 170   // If there are no entries at all, just return NULL.
 171   if (entries == 0)
 172     return NULL;
 173
 174   // Allocate a new environment list.
 175   char **newenv = new char* [entries];
 176   if ((newenv = new char* [entries]) == NULL)
 177     return NULL;
 178
 179   // Make a copy of the list.  Don't forget the NULL that ends the list.
 180   entries = 0;
 181   while (envp[entries] != NULL) {
 182     newenv[entries] = new char[strlen (envp[entries]) + 1];
 183     strcpy (newenv[entries], envp[entries]);
 184     ++entries;
 185   }
 186   newenv[entries] = NULL;
 187
 188   return newenv;
 189 }
 190
 191
 192 /// RemoveEnv - Remove the specified environment variable from the environment
 193 /// array.
 194 ///
 195 /// Inputs:
 196 ///  name - The name of the variable to remove.  It cannot be NULL.
 197 ///  envp - The array of environment variables.  It cannot be NULL.
 198 ///
 199 /// Notes:
 200 ///  This is mainly done because functions to remove items from the environment
 201 ///  are not available across all platforms.  In particular, Solaris does not
 202 ///  seem to have an unsetenv() function or a setenv() function (or they are
 203 ///  undocumented if they do exist).
 204 ///
 205 static void RemoveEnv(const char * name, char ** const envp) {
 206   for (unsigned index=0; envp[index] != NULL; index++) {
 207     // Find the first equals sign in the array and make it an EOS character.
 208     char *p = strchr (envp[index], '=');
 209     if (p == NULL)
 210       continue;
 211     else
 212       *p = '\0';
 213
 214     // Compare the two strings.  If they are equal, zap this string.
 215     // Otherwise, restore it.
 216     if (!strcmp(name, envp[index]))
 217       *envp[index] = '\0';
 218     else
 219       *p = '=';
 220   }
 221
 222   return;
 223 }
 224
 225 /// GenerateBitcode - generates a bitcode file from the module provided
 226 void GenerateBitcode(Module* M, const std::string& FileName) {
 227
 228   if (Verbose)
 229     outs() << "Generating Bitcode To " << FileName << '\n';
 230
 231   // Create the output file.
 232   std::string ErrorInfo;
 233   raw_fd_ostream Out(FileName.c_str(), ErrorInfo,
 234                      raw_fd_ostream::F_Binary);
 235   if (!ErrorInfo.empty())
 236     PrintAndExit(ErrorInfo);
 237
 238   // Ensure that the bitcode file gets removed from the disk if we get a
 239   // terminating signal.
 240   sys::RemoveFileOnSignal(sys::Path(FileName));
 241
 242   // Write it out
 243   WriteBitcodeToFile(M, Out);
 244
 245   // Close the bitcode file.
 246   Out.close();
 247 }
 248
 249 /// GenerateAssembly - generates a native assembly language source file from the
 250 /// specified bitcode file.
 251 ///
 252 /// Inputs:
 253 ///  InputFilename  - The name of the input bitcode file.
 254 ///  OutputFilename - The name of the file to generate.
 255 ///  llc            - The pathname to use for LLC.
 256 ///  envp           - The environment to use when running LLC.
 257 ///
 258 /// Return non-zero value on error.
 259 ///
 260 static int GenerateAssembly(const std::string &OutputFilename,
 261                             const std::string &InputFilename,
 262                             const sys::Path &llc,
 263                             std::string &ErrMsg ) {
 264   // Run LLC to convert the bitcode file into assembly code.
 265   std::vector<const char*> args;
 266   args.push_back(llc.c_str());
 267   // We will use GCC to assemble the program so set the assembly syntax to AT&T,
 268   // regardless of what the target in the bitcode file is.
 269   args.push_back("-x86-asm-syntax=att");
 270   args.push_back("-f");
 271   args.push_back("-o");
 272   args.push_back(OutputFilename.c_str());
 273   args.push_back(InputFilename.c_str());
 274   args.push_back(0);
 275
 276   if (Verbose) {
 277     outs() << "Generating Assembly With: \n";
 278     PrintCommand(args);
 279   }
 280
 281   return sys::Program::ExecuteAndWait(llc, &args[0], 0, 0, 0, 0, &ErrMsg);
 282 }
 283
 284 /// GenerateCFile - generates a C source file from the specified bitcode file.
 285 static int GenerateCFile(const std::string &OutputFile,
 286                          const std::string &InputFile,
 287                          const sys::Path &llc,
 288                          std::string& ErrMsg) {
 289   // Run LLC to convert the bitcode file into C.
 290   std::vector<const char*> args;
 291   args.push_back(llc.c_str());
 292   args.push_back("-march=c");
 293   args.push_back("-f");
 294   args.push_back("-o");
 295   args.push_back(OutputFile.c_str());
 296   args.push_back(InputFile.c_str());
 297   args.push_back(0);
 298
 299   if (Verbose) {
 300     outs() << "Generating C Source With: \n";
 301     PrintCommand(args);
 302   }
 303
 304   return sys::Program::ExecuteAndWait(llc, &args[0], 0, 0, 0, 0, &ErrMsg);
 305 }
 306
 307 /// GenerateNative - generates a native object file from the
 308 /// specified bitcode file.
 309 ///
 310 /// Inputs:
 311 ///  InputFilename   - The name of the input bitcode file.
 312 ///  OutputFilename  - The name of the file to generate.
 313 ///  NativeLinkItems - The native libraries, files, code with which to link
 314 ///  LibPaths        - The list of directories in which to find libraries.
 315 ///  FrameworksPaths - The list of directories in which to find frameworks.
 316 ///  Frameworks      - The list of frameworks (dynamic libraries)
 317 ///  gcc             - The pathname to use for GGC.
 318 ///  envp            - A copy of the process's current environment.
 319 ///
 320 /// Outputs:
 321 ///  None.
 322 ///
 323 /// Returns non-zero value on error.
 324 ///
 325 static int GenerateNative(const std::string &OutputFilename,
 326                           const std::string &InputFilename,
 327                           const Linker::ItemList &LinkItems,
 328                           const sys::Path &gcc, char ** const envp,
 329                           std::string& ErrMsg) {
 330   // Remove these environment variables from the environment of the
 331   // programs that we will execute.  It appears that GCC sets these
 332   // environment variables so that the programs it uses can configure
 333   // themselves identically.
 334   //
 335   // However, when we invoke GCC below, we want it to use its normal
 336   // configuration.  Hence, we must sanitize its environment.
 337   char ** clean_env = CopyEnv(envp);
 338   if (clean_env == NULL)
 339     return 1;
 340   RemoveEnv("LIBRARY_PATH", clean_env);
 341   RemoveEnv("COLLECT_GCC_OPTIONS", clean_env);
 342   RemoveEnv("GCC_EXEC_PREFIX", clean_env);
 343   RemoveEnv("COMPILER_PATH", clean_env);
 344   RemoveEnv("COLLECT_GCC", clean_env);
 345
 346
 347   // Run GCC to assemble and link the program into native code.
 348   //
 349   // Note:
 350   //  We can't just assemble and link the file with the system assembler
 351   //  and linker because we don't know where to put the _start symbol.
 352   //  GCC mysteriously knows how to do it.
 353   std::vector<std::string> args;
 354   args.push_back(gcc.c_str());
 355   args.push_back("-fno-strict-aliasing");
 356   args.push_back("-O3");
 357   args.push_back("-o");
 358   args.push_back(OutputFilename);
 359   args.push_back(InputFilename);
 360
 361   // Add in the library and framework paths
 362   for (unsigned index = 0; index < LibPaths.size(); index++) {
 363     args.push_back("-L" + LibPaths[index]);
 364   }
 365   for (unsigned index = 0; index < FrameworkPaths.size(); index++) {
 366     args.push_back("-F" + FrameworkPaths[index]);
 367   }
 368
 369   // Add the requested options
 370   for (unsigned index = 0; index < XLinker.size(); index++)
 371     args.push_back(XLinker[index]);
 372
 373   // Add in the libraries to link.
 374   for (unsigned index = 0; index < LinkItems.size(); index++)
 375     if (LinkItems[index].first != "crtend") {
 376       if (LinkItems[index].second)
 377         args.push_back("-l" + LinkItems[index].first);
 378       else
 379         args.push_back(LinkItems[index].first);
 380     }
 381
 382   // Add in frameworks to link.
 383   for (unsigned index = 0; index < Frameworks.size(); index++) {
 384     args.push_back("-framework");
 385     args.push_back(Frameworks[index]);
 386   }
 387
 388   // Now that "args" owns all the std::strings for the arguments, call the c_str
 389   // method to get the underlying string array.  We do this game so that the
 390   // std::string array is guaranteed to outlive the const char* array.
 391   std::vector<const char *> Args;
 392   for (unsigned i = 0, e = args.size(); i != e; ++i)
 393     Args.push_back(args[i].c_str());
 394   Args.push_back(0);
 395
 396   if (Verbose) {
 397     outs() << "Generating Native Executable With:\n";
 398     PrintCommand(Args);
 399   }
 400
 401   // Run the compiler to assembly and link together the program.
 402   int R = sys::Program::ExecuteAndWait(
 403     gcc, &Args[0], (const char**)clean_env, 0, 0, 0, &ErrMsg);
 404   delete [] clean_env;
 405   return R;
 406 }
 407
 408 /// EmitShellScript - Output the wrapper file that invokes the JIT on the LLVM
 409 /// bitcode file for the program.
 410 static void EmitShellScript(char **argv) {
 411   if (Verbose)
 412     outs() << "Emitting Shell Script\n";
 413 #if defined(_WIN32) || defined(__CYGWIN__)
 414   // Windows doesn't support #!/bin/sh style shell scripts in .exe files.  To
 415   // support windows systems, we copy the llvm-stub.exe executable from the
 416   // build tree to the destination file.
 417   std::string ErrMsg;
 418   sys::Path llvmstub = FindExecutable("llvm-stub.exe", argv[0],
 419                                       (void *)(intptr_t)&Optimize);
 420   if (llvmstub.isEmpty())
 421     PrintAndExit("Could not find llvm-stub.exe executable!");
 422
 423   if (0 != sys::CopyFile(sys::Path(OutputFilename), llvmstub, &ErrMsg))
 424     PrintAndExit(ErrMsg);
 425
 426   return;
 427 #endif
 428
 429   // Output the script to start the program...
 430   std::string ErrorInfo;
 431   raw_fd_ostream Out2(OutputFilename.c_str(), ErrorInfo);
 432   if (!ErrorInfo.empty())
 433     PrintAndExit(ErrorInfo);
 434
 435   Out2 << "#!/bin/sh\n";
 436   // Allow user to setenv LLVMINTERP if lli is not in their PATH.
 437   Out2 << "lli=${LLVMINTERP-lli}\n";
 438   Out2 << "exec $lli \\\n";
 439   // gcc accepts -l<lib> and implicitly searches /lib and /usr/lib.
 440   LibPaths.push_back("/lib");
 441   LibPaths.push_back("/usr/lib");
 442   LibPaths.push_back("/usr/X11R6/lib");
 443   // We don't need to link in libc! In fact, /usr/lib/libc.so may not be a
 444   // shared object at all! See RH 8: plain text.
 445   std::vector<std::string>::iterator libc =
 446     std::find(Libraries.begin(), Libraries.end(), "c");
 447   if (libc != Libraries.end()) Libraries.erase(libc);
 448   // List all the shared object (native) libraries this executable will need
 449   // on the command line, so that we don't have to do this manually!
 450   for (std::vector<std::string>::iterator i = Libraries.begin(),
 451          e = Libraries.end(); i != e; ++i) {
 452     // try explicit -L arguments first:
 453     sys::Path FullLibraryPath;
 454     for (cl::list<std::string>::const_iterator P = LibPaths.begin(),
 455            E = LibPaths.end(); P != E; ++P) {
 456       FullLibraryPath = *P;
 457       FullLibraryPath.appendComponent("lib" + *i);
 458       FullLibraryPath.appendSuffix(&(LTDL_SHLIB_EXT[1]));
 459       if (!FullLibraryPath.isEmpty()) {
 460         if (!FullLibraryPath.isDynamicLibrary()) {
 461           // Not a native shared library; mark as invalid
 462           FullLibraryPath = sys::Path();
 463         } else break;
 464       }
 465     }
 466     if (FullLibraryPath.isEmpty())
 467       FullLibraryPath = sys::Path::FindLibrary(*i);
 468     if (!FullLibraryPath.isEmpty())
 469       Out2 << "    -load=" << FullLibraryPath.str() << " \\\n";
 470   }
 471   Out2 << "    "  << BitcodeOutputFilename << " ${1+\"$@\"}\n";
 472   Out2.close();
 473 }
 474
 475 // BuildLinkItems -- This function generates a LinkItemList for the LinkItems
 476 // linker function by combining the Files and Libraries in the order they were
 477 // declared on the command line.
 478 static void BuildLinkItems(
 479   Linker::ItemList& Items,
 480   const cl::list<std::string>& Files,
 481   const cl::list<std::string>& Libraries) {
 482
 483   // Build the list of linkage items for LinkItems.
 484
 485   cl::list<std::string>::const_iterator fileIt = Files.begin();
 486   cl::list<std::string>::const_iterator libIt  = Libraries.begin();
 487
 488   int libPos = -1, filePos = -1;
 489   while ( libIt != Libraries.end() || fileIt != Files.end() ) {
 490     if (libIt != Libraries.end())
 491       libPos = Libraries.getPosition(libIt - Libraries.begin());
 492     else
 493       libPos = -1;
 494     if (fileIt != Files.end())
 495       filePos = Files.getPosition(fileIt - Files.begin());
 496     else
 497       filePos = -1;
 498
 499     if (filePos != -1 && (libPos == -1 || filePos < libPos)) {
 500       // Add a source file
 501       Items.push_back(std::make_pair(*fileIt++, false));
 502     } else if (libPos != -1 && (filePos == -1 || libPos < filePos)) {
 503       // Add a library
 504       Items.push_back(std::make_pair(*libIt++, true));
 505     }
 506   }
 507 }
 508
 509 int main(int argc, char **argv, char **envp) {
 510   // Print a stack trace if we signal out.
 511   sys::PrintStackTraceOnErrorSignal();
 512   PrettyStackTraceProgram X(argc, argv);
 513
 514   LLVMContext &Context = getGlobalContext();
 515   llvm_shutdown_obj Y;  // Call llvm_shutdown() on exit.
 516   try {
 517     // Initial global variable above for convenience printing of program name.
 518     progname = sys::Path(argv[0]).getBasename();
 519
 520     // Parse the command line options
 521     cl::ParseCommandLineOptions(argc, argv, "llvm linker\n");
 522
 523     // Construct a Linker (now that Verbose is set)
 524     Linker TheLinker(progname, OutputFilename, Context, Verbose);
 525
 526     // Keep track of the native link items (versus the bitcode items)
 527     Linker::ItemList NativeLinkItems;
 528
 529     // Add library paths to the linker
 530     TheLinker.addPaths(LibPaths);
 531     TheLinker.addSystemPaths();
 532
 533     // Remove any consecutive duplicates of the same library...
 534     Libraries.erase(std::unique(Libraries.begin(), Libraries.end()),
 535                     Libraries.end());
 536
 537     if (LinkAsLibrary) {
 538       std::vector<sys::Path> Files;
 539       for (unsigned i = 0; i < InputFilenames.size(); ++i )
 540         Files.push_back(sys::Path(InputFilenames[i]));
 541       if (TheLinker.LinkInFiles(Files))
 542         return 1; // Error already printed
 543
 544       // The libraries aren't linked in but are noted as "dependent" in the
 545       // module.
 546       for (cl::list<std::string>::const_iterator I = Libraries.begin(),
 547            E = Libraries.end(); I != E ; ++I) {
 548         TheLinker.getModule()->addLibrary(*I);
 549       }
 550     } else {
 551       // Build a list of the items from our command line
 552       Linker::ItemList Items;
 553       BuildLinkItems(Items, InputFilenames, Libraries);
 554
 555       // Link all the items together
 556       if (TheLinker.LinkInItems(Items, NativeLinkItems) )
 557         return 1; // Error already printed
 558     }
 559
 560     std::auto_ptr<Module> Composite(TheLinker.releaseModule());
 561
 562     // Optimize the module
 563     Optimize(Composite.get());
 564
 565 #if defined(_WIN32) || defined(__CYGWIN__)
 566     if (!LinkAsLibrary) {
 567       // Default to "a.exe" instead of "a.out".
 568       if (OutputFilename.getNumOccurrences() == 0)
 569         OutputFilename = "a.exe";
 570
 571       // If there is no suffix add an "exe" one.
 572       sys::Path ExeFile( OutputFilename );
 573       if (ExeFile.getSuffix() == "") {
 574         ExeFile.appendSuffix("exe");
 575         OutputFilename = ExeFile.str();
 576       }
 577     }
 578 #endif
 579
 580     // Generate the bitcode for the optimized module.
 581     // If -b wasn't specified, use the name specified
 582     // with -o to construct BitcodeOutputFilename.
 583     if (BitcodeOutputFilename.empty()) {
 584       BitcodeOutputFilename = OutputFilename;
 585       if (!LinkAsLibrary) BitcodeOutputFilename += ".bc";
 586     }
 587
 588     GenerateBitcode(Composite.get(), BitcodeOutputFilename);
 589
 590     // If we are not linking a library, generate either a native executable
 591     // or a JIT shell script, depending upon what the user wants.
 592     if (!LinkAsLibrary) {
 593       // If the user wants to run a post-link optimization, run it now.
 594       if (!PostLinkOpts.empty()) {
 595         std::vector<std::string> opts = PostLinkOpts;
 596         for (std::vector<std::string>::iterator I = opts.begin(),
 597              E = opts.end(); I != E; ++I) {
 598           sys::Path prog(*I);
 599           if (!prog.canExecute()) {
 600             prog = sys::Program::FindProgramByName(*I);
 601             if (prog.isEmpty())
 602               PrintAndExit(std::string("Optimization program '") + *I +
 603                 "' is not found or not executable.");
 604           }
 605           // Get the program arguments
 606           sys::Path tmp_output("opt_result");
 607           std::string ErrMsg;
 608           if (tmp_output.createTemporaryFileOnDisk(true, &ErrMsg))
 609             PrintAndExit(ErrMsg);
 610
 611           const char* args[4];
 612           args[0] = I->c_str();
 613           args[1] = BitcodeOutputFilename.c_str();
 614           args[2] = tmp_output.c_str();
 615           args[3] = 0;
 616           if (0 == sys::Program::ExecuteAndWait(prog, args, 0,0,0,0, &ErrMsg)) {
 617             if (tmp_output.isBitcodeFile() || tmp_output.isBitcodeFile()) {
 618               sys::Path target(BitcodeOutputFilename);
 619               target.eraseFromDisk();
 620               if (tmp_output.renamePathOnDisk(target, &ErrMsg))
 621                 PrintAndExit(ErrMsg, 2);
 622             } else
 623               PrintAndExit("Post-link optimization output is not bitcode");
 624           } else {
 625             PrintAndExit(ErrMsg);
 626           }
 627         }
 628       }
 629
 630       // If the user wants to generate a native executable, compile it from the
 631       // bitcode file.
 632       //
 633       // Otherwise, create a script that will run the bitcode through the JIT.
 634       if (Native) {
 635         // Name of the Assembly Language output file
 636         sys::Path AssemblyFile ( OutputFilename);
 637         AssemblyFile.appendSuffix("s");
 638
 639         // Mark the output files for removal if we get an interrupt.
 640         sys::RemoveFileOnSignal(AssemblyFile);
 641         sys::RemoveFileOnSignal(sys::Path(OutputFilename));
 642
 643         // Determine the locations of the llc and gcc programs.
 644         sys::Path llc = FindExecutable("llc", argv[0],
 645                                        (void *)(intptr_t)&Optimize);
 646         if (llc.isEmpty())
 647           PrintAndExit("Failed to find llc");
 648
 649         sys::Path gcc = sys::Program::FindProgramByName("gcc");
 650         if (gcc.isEmpty())
 651           PrintAndExit("Failed to find gcc");
 652
 653         // Generate an assembly language file for the bitcode.
 654         std::string ErrMsg;
 655         if (0 != GenerateAssembly(AssemblyFile.str(), BitcodeOutputFilename,
 656             llc, ErrMsg))
 657           PrintAndExit(ErrMsg);
 658
 659         if (0 != GenerateNative(OutputFilename, AssemblyFile.str(),
 660                                 NativeLinkItems, gcc, envp, ErrMsg))
 661           PrintAndExit(ErrMsg);
 662
 663         // Remove the assembly language file.
 664         AssemblyFile.eraseFromDisk();
 665       } else if (NativeCBE) {
 666         sys::Path CFile (OutputFilename);
 667         CFile.appendSuffix("cbe.c");
 668
 669         // Mark the output files for removal if we get an interrupt.
 670         sys::RemoveFileOnSignal(CFile);
 671         sys::RemoveFileOnSignal(sys::Path(OutputFilename));
 672
 673         // Determine the locations of the llc and gcc programs.
 674         sys::Path llc = FindExecutable("llc", argv[0],
 675                                        (void *)(intptr_t)&Optimize);
 676         if (llc.isEmpty())
 677           PrintAndExit("Failed to find llc");
 678
 679         sys::Path gcc = sys::Program::FindProgramByName("gcc");
 680         if (gcc.isEmpty())
 681           PrintAndExit("Failed to find gcc");
 682
 683         // Generate an assembly language file for the bitcode.
 684         std::string ErrMsg;
 685         if (GenerateCFile(CFile.str(), BitcodeOutputFilename, llc, ErrMsg))
 686           PrintAndExit(ErrMsg);
 687
 688         if (GenerateNative(OutputFilename, CFile.str(),
 689                            NativeLinkItems, gcc, envp, ErrMsg))
 690           PrintAndExit(ErrMsg);
 691
 692         // Remove the assembly language file.
 693         CFile.eraseFromDisk();
 694
 695       } else {
 696         EmitShellScript(argv);
 697       }
 698
 699       // Make the script executable...
 700       std::string ErrMsg;
 701       if (sys::Path(OutputFilename).makeExecutableOnDisk(&ErrMsg))
 702         PrintAndExit(ErrMsg);
 703
 704       // Make the bitcode file readable and directly executable in LLEE as well
 705       if (sys::Path(BitcodeOutputFilename).makeExecutableOnDisk(&ErrMsg))
 706         PrintAndExit(ErrMsg);
 707
 708       if (sys::Path(BitcodeOutputFilename).makeReadableOnDisk(&ErrMsg))
 709         PrintAndExit(ErrMsg);
 710     }
 711   } catch (const std::string& msg) {
 712     PrintAndExit(msg,2);
 713   } catch (...) {
 714     PrintAndExit("Unexpected unknown exception occurred.", 2);
 715   }
 716
 717   // Graceful exit
 718   return 0;
 719 }