tools/llc/llc.cpp

   1 //===-- llc.cpp - Implement the LLVM Native Code Generator ----------------===//
   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 is the llc code generator driver. It provides a convenient
  11 // command-line interface for generating native assembly-language code
  12 // or C code, given LLVM bitcode.
  13 //
  14 //===----------------------------------------------------------------------===//
  15
  16 #include "llvm/LLVMContext.h"
  17 #include "llvm/Module.h"
  18 #include "llvm/ModuleProvider.h"
  19 #include "llvm/PassManager.h"
  20 #include "llvm/Pass.h"
  21 #include "llvm/ADT/Triple.h"
  22 #include "llvm/Analysis/Verifier.h"
  23 #include "llvm/Bitcode/ReaderWriter.h"
  24 #include "llvm/CodeGen/FileWriters.h"
  25 #include "llvm/CodeGen/LinkAllAsmWriterComponents.h"
  26 #include "llvm/CodeGen/LinkAllCodegenComponents.h"
  27 #include "llvm/CodeGen/ObjectCodeEmitter.h"
  28 #include "llvm/Config/config.h"
  29 #include "llvm/LinkAllVMCore.h"
  30 #include "llvm/Support/CommandLine.h"
  31 #include "llvm/Support/FileUtilities.h"
  32 #include "llvm/Support/FormattedStream.h"
  33 #include "llvm/Support/ManagedStatic.h"
  34 #include "llvm/Support/MemoryBuffer.h"
  35 #include "llvm/Support/PluginLoader.h"
  36 #include "llvm/Support/PrettyStackTrace.h"
  37 #include "llvm/System/Host.h"
  38 #include "llvm/System/Signals.h"
  39 #include "llvm/Target/SubtargetFeature.h"
  40 #include "llvm/Target/TargetData.h"
  41 #include "llvm/Target/TargetMachine.h"
  42 #include "llvm/Target/TargetRegistry.h"
  43 #include "llvm/Target/TargetSelect.h"
  44 #include "llvm/Transforms/Scalar.h"
  45 #include <memory>
  46 using namespace llvm;
  47
  48 // General options for llc.  Other pass-specific options are specified
  49 // within the corresponding llc passes, and target-specific options
  50 // and back-end code generation options are specified with the target machine.
  51 //
  52 static cl::opt<std::string>
  53 InputFilename(cl::Positional, cl::desc("<input bitcode>"), cl::init("-"));
  54
  55 static cl::opt<std::string>
  56 OutputFilename("o", cl::desc("Output filename"), cl::value_desc("filename"));
  57
  58 static cl::opt<bool> Force("f", cl::desc("Overwrite output files"));
  59
  60 // Determine optimization level.
  61 static cl::opt<char>
  62 OptLevel("O",
  63          cl::desc("Optimization level. [-O0, -O1, -O2, or -O3] "
  64                   "(default = '-O2')"),
  65          cl::Prefix,
  66          cl::ZeroOrMore,
  67          cl::init(' '));
  68
  69 static cl::opt<std::string>
  70 TargetTriple("mtriple", cl::desc("Override target triple for module"));
  71
  72 static cl::opt<std::string>
  73 MArch("march", cl::desc("Architecture to generate code for (see --version)"));
  74
  75 static cl::opt<std::string>
  76 MCPU("mcpu",
  77   cl::desc("Target a specific cpu type (-mcpu=help for details)"),
  78   cl::value_desc("cpu-name"),
  79   cl::init(""));
  80
  81 static cl::list<std::string>
  82 MAttrs("mattr",
  83   cl::CommaSeparated,
  84   cl::desc("Target specific attributes (-mattr=help for details)"),
  85   cl::value_desc("a1,+a2,-a3,..."));
  86
  87 cl::opt<TargetMachine::CodeGenFileType>
  88 FileType("filetype", cl::init(TargetMachine::AssemblyFile),
  89   cl::desc("Choose a file type (not all types are supported by all targets):"),
  90   cl::values(
  91        clEnumValN(TargetMachine::AssemblyFile, "asm",
  92                   "Emit an assembly ('.s') file"),
  93        clEnumValN(TargetMachine::ObjectFile, "obj",
  94                   "Emit a native object ('.o') file [experimental]"),
  95        clEnumValN(TargetMachine::DynamicLibrary, "dynlib",
  96                   "Emit a native dynamic library ('.so') file"
  97                   " [experimental]"),
  98        clEnumValEnd));
  99
 100 cl::opt<bool> NoVerify("disable-verify", cl::Hidden,
 101                        cl::desc("Do not verify input module"));
 102
 103
 104 static cl::opt<bool>
 105 DisableRedZone("disable-red-zone",
 106   cl::desc("Do not emit code that uses the red zone."),
 107   cl::init(false));
 108
 109 static cl::opt<bool>
 110 NoImplicitFloats("no-implicit-float",
 111   cl::desc("Don't generate implicit floating point instructions (x86-only)"),
 112   cl::init(false));
 113
 114 // GetFileNameRoot - Helper function to get the basename of a filename.
 115 static inline std::string
 116 GetFileNameRoot(const std::string &InputFilename) {
 117   std::string IFN = InputFilename;
 118   std::string outputFilename;
 119   int Len = IFN.length();
 120   if ((Len > 2) &&
 121       IFN[Len-3] == '.' && IFN[Len-2] == 'b' && IFN[Len-1] == 'c') {
 122     outputFilename = std::string(IFN.begin(), IFN.end()-3); // s/.bc/.s/
 123   } else {
 124     outputFilename = IFN;
 125   }
 126   return outputFilename;
 127 }
 128
 129 static formatted_raw_ostream *GetOutputStream(const char *TargetName,
 130                                               const char *ProgName) {
 131   if (OutputFilename != "") {
 132     if (OutputFilename == "-")
 133       return &fouts();
 134
 135     // Make sure that the Out file gets unlinked from the disk if we get a
 136     // SIGINT
 137     sys::RemoveFileOnSignal(sys::Path(OutputFilename));
 138
 139     std::string error;
 140     raw_fd_ostream *FDOut = new raw_fd_ostream(OutputFilename.c_str(),
 141                                                /*Binary=*/true, Force, error);
 142     if (!error.empty()) {
 143       errs() << error << '\n';
 144       if (!Force)
 145         errs() << "Use -f command line argument to force output\n";
 146       delete FDOut;
 147       return 0;
 148     }
 149     formatted_raw_ostream *Out =
 150       new formatted_raw_ostream(*FDOut, formatted_raw_ostream::DELETE_STREAM);
 151
 152     return Out;
 153   }
 154
 155   if (InputFilename == "-") {
 156     OutputFilename = "-";
 157     return &fouts();
 158   }
 159
 160   OutputFilename = GetFileNameRoot(InputFilename);
 161
 162   bool Binary = false;
 163   switch (FileType) {
 164   case TargetMachine::AssemblyFile:
 165     if (TargetName[0] == 'c') {
 166       if (TargetName[1] == 0)
 167         OutputFilename += ".cbe.c";
 168       else if (TargetName[1] == 'p' && TargetName[2] == 'p')
 169         OutputFilename += ".cpp";
 170       else
 171         OutputFilename += ".s";
 172     } else
 173       OutputFilename += ".s";
 174     break;
 175   case TargetMachine::ObjectFile:
 176     OutputFilename += ".o";
 177     Binary = true;
 178     break;
 179   case TargetMachine::DynamicLibrary:
 180     OutputFilename += LTDL_SHLIB_EXT;
 181     Binary = true;
 182     break;
 183   }
 184
 185   // Make sure that the Out file gets unlinked from the disk if we get a
 186   // SIGINT
 187   sys::RemoveFileOnSignal(sys::Path(OutputFilename));
 188
 189   std::string error;
 190   raw_fd_ostream *FDOut = new raw_fd_ostream(OutputFilename.c_str(),
 191                                              Binary, Force, error);
 192   if (!error.empty()) {
 193     errs() << error << '\n';
 194     if (!Force)
 195       errs() << "Use -f command line argument to force output\n";
 196     delete FDOut;
 197     return 0;
 198   }
 199
 200   formatted_raw_ostream *Out =
 201     new formatted_raw_ostream(*FDOut, formatted_raw_ostream::DELETE_STREAM);
 202
 203   return Out;
 204 }
 205
 206 // main - Entry point for the llc compiler.
 207 //
 208 int main(int argc, char **argv) {
 209   sys::PrintStackTraceOnErrorSignal();
 210   PrettyStackTraceProgram X(argc, argv);
 211   LLVMContext &Context = getGlobalContext();
 212   llvm_shutdown_obj Y;  // Call llvm_shutdown() on exit.
 213
 214   // Initialize targets first.
 215   InitializeAllTargets();
 216   InitializeAllAsmPrinters();
 217
 218   cl::ParseCommandLineOptions(argc, argv, "llvm system compiler\n");
 219
 220   // Load the module to be compiled...
 221   std::string ErrorMessage;
 222   std::auto_ptr<Module> M;
 223
 224   std::auto_ptr<MemoryBuffer> Buffer(
 225                    MemoryBuffer::getFileOrSTDIN(InputFilename, &ErrorMessage));
 226   if (Buffer.get())
 227     M.reset(ParseBitcodeFile(Buffer.get(), Context, &ErrorMessage));
 228   if (M.get() == 0) {
 229     errs() << argv[0] << ": bitcode didn't read correctly.\n";
 230     errs() << "Reason: " << ErrorMessage << "\n";
 231     return 1;
 232   }
 233   Module &mod = *M.get();
 234
 235   // If we are supposed to override the target triple, do so now.
 236   if (!TargetTriple.empty())
 237     mod.setTargetTriple(TargetTriple);
 238
 239   Triple TheTriple(mod.getTargetTriple());
 240   if (TheTriple.getTriple().empty())
 241     TheTriple.setTriple(sys::getHostTriple());
 242
 243   // Allocate target machine.  First, check whether the user has explicitly
 244   // specified an architecture to compile for. If so we have to look it up by
 245   // name, because it might be a backend that has no mapping to a target triple.
 246   const Target *TheTarget = 0;
 247   if (!MArch.empty()) {
 248     for (TargetRegistry::iterator it = TargetRegistry::begin(),
 249            ie = TargetRegistry::end(); it != ie; ++it) {
 250       if (MArch == it->getName()) {
 251         TheTarget = &*it;
 252         break;
 253       }
 254     }
 255
 256     if (!TheTarget) {
 257       errs() << argv[0] << ": error: invalid target '" << MArch << "'.\n";
 258       return 1;
 259     }
 260
 261     // Adjust the triple to match (if known), otherwise stick with the
 262     // module/host triple.
 263     Triple::ArchType Type = Triple::getArchTypeForLLVMName(MArch);
 264     if (Type != Triple::UnknownArch)
 265       TheTriple.setArch(Type);
 266   } else {
 267     std::string Err;
 268     TheTarget = TargetRegistry::lookupTarget(TheTriple.getTriple(), Err);
 269     if (TheTarget == 0) {
 270       errs() << argv[0] << ": error auto-selecting target for module '"
 271              << Err << "'.  Please use the -march option to explicitly "
 272              << "pick a target.\n";
 273       return 1;
 274     }
 275   }
 276
 277   // Package up features to be passed to target/subtarget
 278   std::string FeaturesStr;
 279   if (MCPU.size() || MAttrs.size()) {
 280     SubtargetFeatures Features;
 281     Features.setCPU(MCPU);
 282     for (unsigned i = 0; i != MAttrs.size(); ++i)
 283       Features.AddFeature(MAttrs[i]);
 284     FeaturesStr = Features.getString();
 285   }
 286
 287   std::auto_ptr<TargetMachine>
 288     target(TheTarget->createTargetMachine(TheTriple.getTriple(), FeaturesStr));
 289   assert(target.get() && "Could not allocate target machine!");
 290   TargetMachine &Target = *target.get();
 291
 292   // Figure out where we are going to send the output...
 293   formatted_raw_ostream *Out = GetOutputStream(TheTarget->getName(), argv[0]);
 294   if (Out == 0) return 1;
 295
 296   CodeGenOpt::Level OLvl = CodeGenOpt::Default;
 297   switch (OptLevel) {
 298   default:
 299     errs() << argv[0] << ": invalid optimization level.\n";
 300     return 1;
 301   case ' ': break;
 302   case '0': OLvl = CodeGenOpt::None; break;
 303   case '1':
 304   case '2': OLvl = CodeGenOpt::Default; break;
 305   case '3': OLvl = CodeGenOpt::Aggressive; break;
 306   }
 307
 308   // If this target requires addPassesToEmitWholeFile, do it now.  This is
 309   // used by strange things like the C backend.
 310   if (Target.WantsWholeFile()) {
 311     PassManager PM;
 312
 313     // Add the target data from the target machine, if it exists, or the module.
 314     if (const TargetData *TD = Target.getTargetData())
 315       PM.add(new TargetData(*TD));
 316     else
 317       PM.add(new TargetData(&mod));
 318
 319     if (!NoVerify)
 320       PM.add(createVerifierPass());
 321
 322     // Ask the target to add backend passes as necessary.
 323     if (Target.addPassesToEmitWholeFile(PM, *Out, FileType, OLvl)) {
 324       errs() << argv[0] << ": target does not support generation of this"
 325              << " file type!\n";
 326       if (Out != &fouts()) delete Out;
 327       // And the Out file is empty and useless, so remove it now.
 328       sys::Path(OutputFilename).eraseFromDisk();
 329       return 1;
 330     }
 331     PM.run(mod);
 332   } else {
 333     // Build up all of the passes that we want to do to the module.
 334     ExistingModuleProvider Provider(M.release());
 335     FunctionPassManager Passes(&Provider);
 336
 337     // Add the target data from the target machine, if it exists, or the module.
 338     if (const TargetData *TD = Target.getTargetData())
 339       Passes.add(new TargetData(*TD));
 340     else
 341       Passes.add(new TargetData(&mod));
 342
 343 #ifndef NDEBUG
 344     if (!NoVerify)
 345       Passes.add(createVerifierPass());
 346 #endif
 347
 348     // Ask the target to add backend passes as necessary.
 349     ObjectCodeEmitter *OCE = 0;
 350
 351     // Override default to generate verbose assembly.
 352     Target.setAsmVerbosityDefault(true);
 353
 354     switch (Target.addPassesToEmitFile(Passes, *Out, FileType, OLvl)) {
 355     default:
 356       assert(0 && "Invalid file model!");
 357       return 1;
 358     case FileModel::Error:
 359       errs() << argv[0] << ": target does not support generation of this"
 360              << " file type!\n";
 361       if (Out != &fouts()) delete Out;
 362       // And the Out file is empty and useless, so remove it now.
 363       sys::Path(OutputFilename).eraseFromDisk();
 364       return 1;
 365     case FileModel::AsmFile:
 366       break;
 367     case FileModel::MachOFile:
 368       OCE = AddMachOWriter(Passes, *Out, Target);
 369       break;
 370     case FileModel::ElfFile:
 371       OCE = AddELFWriter(Passes, *Out, Target);
 372       break;
 373     }
 374
 375     if (Target.addPassesToEmitFileFinish(Passes, OCE, OLvl)) {
 376       errs() << argv[0] << ": target does not support generation of this"
 377              << " file type!\n";
 378       if (Out != &fouts()) delete Out;
 379       // And the Out file is empty and useless, so remove it now.
 380       sys::Path(OutputFilename).eraseFromDisk();
 381       return 1;
 382     }
 383
 384     Passes.doInitialization();
 385
 386     // Run our queue of passes all at once now, efficiently.
 387     // TODO: this could lazily stream functions out of the module.
 388     for (Module::iterator I = mod.begin(), E = mod.end(); I != E; ++I)
 389       if (!I->isDeclaration()) {
 390         if (DisableRedZone)
 391           I->addFnAttr(Attribute::NoRedZone);
 392         if (NoImplicitFloats)
 393           I->addFnAttr(Attribute::NoImplicitFloat);
 394         Passes.run(*I);
 395       }
 396
 397     Passes.doFinalization();
 398   }
 399
 400   Out->flush();
 401
 402   // Delete the ostream if it's not a stdout stream
 403   if (Out != &fouts()) delete Out;
 404
 405   return 0;
 406 }