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/PassManager.h"
  19 #include "llvm/Pass.h"
  20 #include "llvm/ADT/Triple.h"
  21 #include "llvm/Support/IRReader.h"
  22 #include "llvm/CodeGen/LinkAllAsmWriterComponents.h"
  23 #include "llvm/CodeGen/LinkAllCodegenComponents.h"
  24 #include "llvm/Config/config.h"
  25 #include "llvm/Support/CommandLine.h"
  26 #include "llvm/Support/Debug.h"
  27 #include "llvm/Support/FormattedStream.h"
  28 #include "llvm/Support/ManagedStatic.h"
  29 #include "llvm/Support/PluginLoader.h"
  30 #include "llvm/Support/PrettyStackTrace.h"
  31 #include "llvm/Support/ToolOutputFile.h"
  32 #include "llvm/System/Host.h"
  33 #include "llvm/System/Signals.h"
  34 #include "llvm/Target/SubtargetFeature.h"
  35 #include "llvm/Target/TargetData.h"
  36 #include "llvm/Target/TargetMachine.h"
  37 #include "llvm/Target/TargetRegistry.h"
  38 #include "llvm/Target/TargetSelect.h"
  39 #include <memory>
  40 using namespace llvm;
  41
  42 // General options for llc.  Other pass-specific options are specified
  43 // within the corresponding llc passes, and target-specific options
  44 // and back-end code generation options are specified with the target machine.
  45 //
  46 static cl::opt<std::string>
  47 InputFilename(cl::Positional, cl::desc("<input bitcode>"), cl::init("-"));
  48
  49 static cl::opt<std::string>
  50 OutputFilename("o", cl::desc("Output filename"), cl::value_desc("filename"));
  51
  52 // Determine optimization level.
  53 static cl::opt<char>
  54 OptLevel("O",
  55          cl::desc("Optimization level. [-O0, -O1, -O2, or -O3] "
  56                   "(default = '-O2')"),
  57          cl::Prefix,
  58          cl::ZeroOrMore,
  59          cl::init(' '));
  60
  61 static cl::opt<std::string>
  62 TargetTriple("mtriple", cl::desc("Override target triple for module"));
  63
  64 static cl::opt<std::string>
  65 MArch("march", cl::desc("Architecture to generate code for (see --version)"));
  66
  67 static cl::opt<std::string>
  68 MCPU("mcpu",
  69   cl::desc("Target a specific cpu type (-mcpu=help for details)"),
  70   cl::value_desc("cpu-name"),
  71   cl::init(""));
  72
  73 static cl::list<std::string>
  74 MAttrs("mattr",
  75   cl::CommaSeparated,
  76   cl::desc("Target specific attributes (-mattr=help for details)"),
  77   cl::value_desc("a1,+a2,-a3,..."));
  78
  79 static cl::opt<bool>
  80 RelaxAll("mc-relax-all",
  81   cl::desc("When used with filetype=obj, "
  82            "relax all fixups in the emitted object file"));
  83
  84 cl::opt<TargetMachine::CodeGenFileType>
  85 FileType("filetype", cl::init(TargetMachine::CGFT_AssemblyFile),
  86   cl::desc("Choose a file type (not all types are supported by all targets):"),
  87   cl::values(
  88        clEnumValN(TargetMachine::CGFT_AssemblyFile, "asm",
  89                   "Emit an assembly ('.s') file"),
  90        clEnumValN(TargetMachine::CGFT_ObjectFile, "obj",
  91                   "Emit a native object ('.o') file [experimental]"),
  92        clEnumValN(TargetMachine::CGFT_Null, "null",
  93                   "Emit nothing, for performance testing"),
  94        clEnumValEnd));
  95
  96 cl::opt<bool> NoVerify("disable-verify", cl::Hidden,
  97                        cl::desc("Do not verify input module"));
  98
  99
 100 static cl::opt<bool>
 101 DisableRedZone("disable-red-zone",
 102   cl::desc("Do not emit code that uses the red zone."),
 103   cl::init(false));
 104
 105 static cl::opt<bool>
 106 NoImplicitFloats("no-implicit-float",
 107   cl::desc("Don't generate implicit floating point instructions (x86-only)"),
 108   cl::init(false));
 109
 110 // GetFileNameRoot - Helper function to get the basename of a filename.
 111 static inline std::string
 112 GetFileNameRoot(const std::string &InputFilename) {
 113   std::string IFN = InputFilename;
 114   std::string outputFilename;
 115   int Len = IFN.length();
 116   if ((Len > 2) &&
 117       IFN[Len-3] == '.' &&
 118       ((IFN[Len-2] == 'b' && IFN[Len-1] == 'c') ||
 119        (IFN[Len-2] == 'l' && IFN[Len-1] == 'l'))) {
 120     outputFilename = std::string(IFN.begin(), IFN.end()-3); // s/.bc/.s/
 121   } else {
 122     outputFilename = IFN;
 123   }
 124   return outputFilename;
 125 }
 126
 127 static tool_output_file *GetOutputStream(const char *TargetName,
 128                                          Triple::OSType OS,
 129                                          const char *ProgName) {
 130   // If we don't yet have an output filename, make one.
 131   if (OutputFilename.empty()) {
 132     if (InputFilename == "-")
 133       OutputFilename = "-";
 134     else {
 135       OutputFilename = GetFileNameRoot(InputFilename);
 136
 137       switch (FileType) {
 138       default: assert(0 && "Unknown file type");
 139       case TargetMachine::CGFT_AssemblyFile:
 140         if (TargetName[0] == 'c') {
 141           if (TargetName[1] == 0)
 142             OutputFilename += ".cbe.c";
 143           else if (TargetName[1] == 'p' && TargetName[2] == 'p')
 144             OutputFilename += ".cpp";
 145           else
 146             OutputFilename += ".s";
 147         } else
 148           OutputFilename += ".s";
 149         break;
 150       case TargetMachine::CGFT_ObjectFile:
 151         if (OS == Triple::Win32)
 152           OutputFilename += ".obj";
 153         else
 154           OutputFilename += ".o";
 155         break;
 156       case TargetMachine::CGFT_Null:
 157         OutputFilename += ".null";
 158         break;
 159       }
 160     }
 161   }
 162
 163   // Decide if we need "binary" output.
 164   bool Binary = false;
 165   switch (FileType) {
 166   default: assert(0 && "Unknown file type");
 167   case TargetMachine::CGFT_AssemblyFile:
 168     break;
 169   case TargetMachine::CGFT_ObjectFile:
 170   case TargetMachine::CGFT_Null:
 171     Binary = true;
 172     break;
 173   }
 174
 175   // Open the file.
 176   std::string error;
 177   unsigned OpenFlags = 0;
 178   if (Binary) OpenFlags |= raw_fd_ostream::F_Binary;
 179   tool_output_file *FDOut = new tool_output_file(OutputFilename.c_str(), error,
 180                                                  OpenFlags);
 181   if (!error.empty()) {
 182     errs() << error << '\n';
 183     delete FDOut;
 184     return 0;
 185   }
 186
 187   return FDOut;
 188 }
 189
 190 // main - Entry point for the llc compiler.
 191 //
 192 int main(int argc, char **argv) {
 193   sys::PrintStackTraceOnErrorSignal();
 194   PrettyStackTraceProgram X(argc, argv);
 195
 196   // Enable debug stream buffering.
 197   EnableDebugBuffering = true;
 198
 199   LLVMContext &Context = getGlobalContext();
 200   llvm_shutdown_obj Y;  // Call llvm_shutdown() on exit.
 201
 202   // Initialize targets first, so that --version shows registered targets.
 203   InitializeAllTargets();
 204   InitializeAllAsmPrinters();
 205   InitializeAllAsmParsers();
 206
 207   cl::ParseCommandLineOptions(argc, argv, "llvm system compiler\n");
 208
 209   // Load the module to be compiled...
 210   SMDiagnostic Err;
 211   std::auto_ptr<Module> M;
 212
 213   M.reset(ParseIRFile(InputFilename, Err, Context));
 214   if (M.get() == 0) {
 215     Err.Print(argv[0], errs());
 216     return 1;
 217   }
 218   Module &mod = *M.get();
 219
 220   // If we are supposed to override the target triple, do so now.
 221   if (!TargetTriple.empty())
 222     mod.setTargetTriple(Triple::normalize(TargetTriple));
 223
 224   Triple TheTriple(mod.getTargetTriple());
 225   if (TheTriple.getTriple().empty())
 226     TheTriple.setTriple(sys::getHostTriple());
 227
 228   // Allocate target machine.  First, check whether the user has explicitly
 229   // specified an architecture to compile for. If so we have to look it up by
 230   // name, because it might be a backend that has no mapping to a target triple.
 231   const Target *TheTarget = 0;
 232   if (!MArch.empty()) {
 233     for (TargetRegistry::iterator it = TargetRegistry::begin(),
 234            ie = TargetRegistry::end(); it != ie; ++it) {
 235       if (MArch == it->getName()) {
 236         TheTarget = &*it;
 237         break;
 238       }
 239     }
 240
 241     if (!TheTarget) {
 242       errs() << argv[0] << ": error: invalid target '" << MArch << "'.\n";
 243       return 1;
 244     }
 245
 246     // Adjust the triple to match (if known), otherwise stick with the
 247     // module/host triple.
 248     Triple::ArchType Type = Triple::getArchTypeForLLVMName(MArch);
 249     if (Type != Triple::UnknownArch)
 250       TheTriple.setArch(Type);
 251   } else {
 252     std::string Err;
 253     TheTarget = TargetRegistry::lookupTarget(TheTriple.getTriple(), Err);
 254     if (TheTarget == 0) {
 255       errs() << argv[0] << ": error auto-selecting target for module '"
 256              << Err << "'.  Please use the -march option to explicitly "
 257              << "pick a target.\n";
 258       return 1;
 259     }
 260   }
 261
 262   // Package up features to be passed to target/subtarget
 263   std::string FeaturesStr;
 264   if (MCPU.size() || MAttrs.size()) {
 265     SubtargetFeatures Features;
 266     Features.setCPU(MCPU);
 267     for (unsigned i = 0; i != MAttrs.size(); ++i)
 268       Features.AddFeature(MAttrs[i]);
 269     FeaturesStr = Features.getString();
 270   }
 271
 272   std::auto_ptr<TargetMachine>
 273     target(TheTarget->createTargetMachine(TheTriple.getTriple(), FeaturesStr));
 274   assert(target.get() && "Could not allocate target machine!");
 275   TargetMachine &Target = *target.get();
 276
 277   // Figure out where we are going to send the output...
 278   OwningPtr<tool_output_file> Out
 279     (GetOutputStream(TheTarget->getName(), TheTriple.getOS(), argv[0]));
 280   if (!Out) return 1;
 281
 282   CodeGenOpt::Level OLvl = CodeGenOpt::Default;
 283   switch (OptLevel) {
 284   default:
 285     errs() << argv[0] << ": invalid optimization level.\n";
 286     return 1;
 287   case ' ': break;
 288   case '0': OLvl = CodeGenOpt::None; break;
 289   case '1': OLvl = CodeGenOpt::Less; break;
 290   case '2': OLvl = CodeGenOpt::Default; break;
 291   case '3': OLvl = CodeGenOpt::Aggressive; break;
 292   }
 293
 294   // Build up all of the passes that we want to do to the module.
 295   PassManager PM;
 296
 297   // Add the target data from the target machine, if it exists, or the module.
 298   if (const TargetData *TD = Target.getTargetData())
 299     PM.add(new TargetData(*TD));
 300   else
 301     PM.add(new TargetData(&mod));
 302
 303   // Override default to generate verbose assembly.
 304   Target.setAsmVerbosityDefault(true);
 305
 306   if (RelaxAll) {
 307     if (FileType != TargetMachine::CGFT_ObjectFile)
 308       errs() << argv[0]
 309              << ": warning: ignoring -mc-relax-all because filetype != obj";
 310     else
 311       Target.setMCRelaxAll(true);
 312   }
 313
 314   {
 315     formatted_raw_ostream FOS(Out->os());
 316
 317     // Ask the target to add backend passes as necessary.
 318     if (Target.addPassesToEmitFile(PM, FOS, FileType, OLvl, NoVerify)) {
 319       errs() << argv[0] << ": target does not support generation of this"
 320              << " file type!\n";
 321       return 1;
 322     }
 323
 324     PM.run(mod);
 325   }
 326
 327   // Declare success.
 328   Out->keep();
 329
 330   return 0;
 331 }