src/llvm/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/IR/LLVMContext.h"
  17 #include "llvm/ADT/Triple.h"
  18 #include "llvm/Assembly/PrintModulePass.h"
  19 #include "llvm/CodeGen/CommandFlags.h"
  20 #include "llvm/CodeGen/LinkAllAsmWriterComponents.h"
  21 #include "llvm/CodeGen/LinkAllCodegenComponents.h"
  22 #include "llvm/IR/DataLayout.h"
  23 #include "llvm/IR/Module.h"
  24 #include "llvm/MC/SubtargetFeature.h"
  25 #include "llvm/Pass.h"
  26 #include "llvm/PassManager.h"
  27 #include "llvm/Support/CommandLine.h"
  28 #include "llvm/Support/Debug.h"
  29 #include "llvm/Support/FormattedStream.h"
  30 #include "llvm/Support/Host.h"
  31 #include "llvm/Support/IRReader.h"
  32 #include "llvm/Support/ManagedStatic.h"
  33 #include "llvm/Support/PluginLoader.h"
  34 #include "llvm/Support/PrettyStackTrace.h"
  35 #include "llvm/Support/Signals.h"
  36 #include "llvm/Support/TargetRegistry.h"
  37 #include "llvm/Support/TargetSelect.h"
  38 #include "llvm/Support/ToolOutputFile.h"
  39 #include "llvm/Target/TargetLibraryInfo.h"
  40 #include "llvm/Target/TargetMachine.h"
  41 #include <memory>
  42 using namespace llvm;
  43
  44 // General options for llc.  Other pass-specific options are specified
  45 // within the corresponding llc passes, and target-specific options
  46 // and back-end code generation options are specified with the target machine.
  47 //
  48 static cl::opt<std::string>
  49 InputFilename(cl::Positional, cl::desc("<input bitcode>"), cl::init("-"));
  50
  51 static cl::opt<std::string>
  52 OutputFilename("o", cl::desc("Output filename"), cl::value_desc("filename"));
  53
  54 static cl::opt<unsigned>
  55 TimeCompilations("time-compilations", cl::Hidden, cl::init(1u),
  56                  cl::value_desc("N"),
  57                  cl::desc("Repeat compilation N times for timing"));
  58
  59 // Determine optimization level.
  60 static cl::opt<char>
  61 OptLevel("O",
  62          cl::desc("Optimization level. [-O0, -O1, -O2, or -O3] "
  63                   "(default = '-O2')"),
  64          cl::Prefix,
  65          cl::ZeroOrMore,
  66          cl::init(' '));
  67
  68 static cl::opt<std::string>
  69 TargetTriple("mtriple", cl::desc("Override target triple for module"));
  70
  71 cl::opt<bool> NoVerify("disable-verify", cl::Hidden,
  72                        cl::desc("Do not verify input module"));
  73
  74 cl::opt<bool>
  75 DisableSimplifyLibCalls("disable-simplify-libcalls",
  76                         cl::desc("Disable simplify-libcalls"),
  77                         cl::init(false));
  78
  79 static int compileModule(char**, LLVMContext&);
  80
  81 // GetFileNameRoot - Helper function to get the basename of a filename.
  82 static inline std::string
  83 GetFileNameRoot(const std::string &InputFilename) {
  84   std::string IFN = InputFilename;
  85   std::string outputFilename;
  86   int Len = IFN.length();
  87   if ((Len > 2) &&
  88       IFN[Len-3] == '.' &&
  89       ((IFN[Len-2] == 'b' && IFN[Len-1] == 'c') ||
  90        (IFN[Len-2] == 'l' && IFN[Len-1] == 'l'))) {
  91     outputFilename = std::string(IFN.begin(), IFN.end()-3); // s/.bc/.s/
  92   } else {
  93     outputFilename = IFN;
  94   }
  95   return outputFilename;
  96 }
  97
  98 static tool_output_file *GetOutputStream(const char *TargetName,
  99                                          Triple::OSType OS,
 100                                          const char *ProgName) {
 101   // If we don't yet have an output filename, make one.
 102   if (OutputFilename.empty()) {
 103     if (InputFilename == "-")
 104       OutputFilename = "-";
 105     else {
 106       OutputFilename = GetFileNameRoot(InputFilename);
 107
 108       switch (FileType) {
 109       case TargetMachine::CGFT_AssemblyFile:
 110         if (TargetName[0] == 'c') {
 111           if (TargetName[1] == 0)
 112             OutputFilename += ".cbe.c";
 113           else if (TargetName[1] == 'p' && TargetName[2] == 'p')
 114             OutputFilename += ".cpp";
 115           else
 116             OutputFilename += ".s";
 117         } else
 118           OutputFilename += ".s";
 119         break;
 120       case TargetMachine::CGFT_ObjectFile:
 121         if (OS == Triple::Win32)
 122           OutputFilename += ".obj";
 123         else
 124           OutputFilename += ".o";
 125         break;
 126       case TargetMachine::CGFT_Null:
 127         OutputFilename += ".null";
 128         break;
 129       }
 130     }
 131   }
 132
 133   // Decide if we need "binary" output.
 134   bool Binary = false;
 135   switch (FileType) {
 136   case TargetMachine::CGFT_AssemblyFile:
 137     break;
 138   case TargetMachine::CGFT_ObjectFile:
 139   case TargetMachine::CGFT_Null:
 140     Binary = true;
 141     break;
 142   }
 143
 144   // Open the file.
 145   std::string error;
 146   unsigned OpenFlags = 0;
 147   if (Binary) OpenFlags |= raw_fd_ostream::F_Binary;
 148   tool_output_file *FDOut = new tool_output_file(OutputFilename.c_str(), error,
 149                                                  OpenFlags);
 150   if (!error.empty()) {
 151     errs() << error << '\n';
 152     delete FDOut;
 153     return 0;
 154   }
 155
 156   return FDOut;
 157 }
 158
 159 // main - Entry point for the llc compiler.
 160 //
 161 int main(int argc, char **argv) {
 162   sys::PrintStackTraceOnErrorSignal();
 163   PrettyStackTraceProgram X(argc, argv);
 164
 165   // Enable debug stream buffering.
 166   EnableDebugBuffering = true;
 167
 168   LLVMContext &Context = getGlobalContext();
 169   llvm_shutdown_obj Y;  // Call llvm_shutdown() on exit.
 170
 171   // Initialize targets first, so that --version shows registered targets.
 172   InitializeAllTargets();
 173   InitializeAllTargetMCs();
 174   InitializeAllAsmPrinters();
 175   InitializeAllAsmParsers();
 176
 177   // Initialize codegen and IR passes used by llc so that the -print-after,
 178   // -print-before, and -stop-after options work.
 179   PassRegistry *Registry = PassRegistry::getPassRegistry();
 180   initializeCore(*Registry);
 181   initializeCodeGen(*Registry);
 182   initializeLoopStrengthReducePass(*Registry);
 183   initializeLowerIntrinsicsPass(*Registry);
 184   initializeUnreachableBlockElimPass(*Registry);
 185
 186   // Register the target printer for --version.
 187   cl::AddExtraVersionPrinter(TargetRegistry::printRegisteredTargetsForVersion);
 188
 189   cl::ParseCommandLineOptions(argc, argv, "llvm system compiler\n");
 190
 191   // Compile the module TimeCompilations times to give better compile time
 192   // metrics.
 193   for (unsigned I = TimeCompilations; I; --I)
 194     if (int RetVal = compileModule(argv, Context))
 195       return RetVal;
 196   return 0;
 197 }
 198
 199 static int compileModule(char **argv, LLVMContext &Context) {
 200   // Load the module to be compiled...
 201   SMDiagnostic Err;
 202   std::auto_ptr<Module> M;
 203   Module *mod = 0;
 204   Triple TheTriple;
 205
 206   bool SkipModule = MCPU == "help" ||
 207                     (!MAttrs.empty() && MAttrs.front() == "help");
 208
 209   // If user just wants to list available options, skip module loading
 210   if (!SkipModule) {
 211     M.reset(ParseIRFile(InputFilename, Err, Context));
 212     mod = M.get();
 213     if (mod == 0) {
 214       Err.print(argv[0], errs());
 215       return 1;
 216     }
 217
 218     // If we are supposed to override the target triple, do so now.
 219     if (!TargetTriple.empty())
 220       mod->setTargetTriple(Triple::normalize(TargetTriple));
 221     TheTriple = Triple(mod->getTargetTriple());
 222   } else {
 223     TheTriple = Triple(Triple::normalize(TargetTriple));
 224   }
 225
 226   if (TheTriple.getTriple().empty())
 227     TheTriple.setTriple(sys::getDefaultTargetTriple());
 228
 229   // Get the target specific parser.
 230   std::string Error;
 231   const Target *TheTarget = TargetRegistry::lookupTarget(MArch, TheTriple,
 232                                                          Error);
 233   if (!TheTarget) {
 234     errs() << argv[0] << ": " << Error;
 235     return 1;
 236   }
 237
 238   // Package up features to be passed to target/subtarget
 239   std::string FeaturesStr;
 240   if (MAttrs.size()) {
 241     SubtargetFeatures Features;
 242     for (unsigned i = 0; i != MAttrs.size(); ++i)
 243       Features.AddFeature(MAttrs[i]);
 244     FeaturesStr = Features.getString();
 245   }
 246
 247   CodeGenOpt::Level OLvl = CodeGenOpt::Default;
 248   switch (OptLevel) {
 249   default:
 250     errs() << argv[0] << ": invalid optimization level.\n";
 251     return 1;
 252   case ' ': break;
 253   case '0': OLvl = CodeGenOpt::None; break;
 254   case '1': OLvl = CodeGenOpt::Less; break;
 255   case '2': OLvl = CodeGenOpt::Default; break;
 256   case '3': OLvl = CodeGenOpt::Aggressive; break;
 257   }
 258
 259   TargetOptions Options;
 260   Options.LessPreciseFPMADOption = EnableFPMAD;
 261   Options.NoFramePointerElim = DisableFPElim;
 262   Options.NoFramePointerElimNonLeaf = DisableFPElimNonLeaf;
 263   Options.AllowFPOpFusion = FuseFPOps;
 264   Options.UnsafeFPMath = EnableUnsafeFPMath;
 265   Options.NoInfsFPMath = EnableNoInfsFPMath;
 266   Options.NoNaNsFPMath = EnableNoNaNsFPMath;
 267   Options.HonorSignDependentRoundingFPMathOption =
 268       EnableHonorSignDependentRoundingFPMath;
 269   Options.UseSoftFloat = GenerateSoftFloatCalls;
 270   if (FloatABIForCalls != FloatABI::Default)
 271     Options.FloatABIType = FloatABIForCalls;
 272   Options.NoZerosInBSS = DontPlaceZerosInBSS;
 273   Options.GuaranteedTailCallOpt = EnableGuaranteedTailCallOpt;
 274   Options.DisableTailCalls = DisableTailCalls;
 275   Options.StackAlignmentOverride = OverrideStackAlignment;
 276   Options.RealignStack = EnableRealignStack;
 277   Options.TrapFuncName = TrapFuncName;
 278   Options.PositionIndependentExecutable = EnablePIE;
 279   Options.EnableSegmentedStacks = SegmentedStacks;
 280   Options.UseInitArray = UseInitArray;
 281   Options.SSPBufferSize = SSPBufferSize;
 282
 283   std::auto_ptr<TargetMachine>
 284     target(TheTarget->createTargetMachine(TheTriple.getTriple(),
 285                                           MCPU, FeaturesStr, Options,
 286                                           RelocModel, CMModel, OLvl));
 287   assert(target.get() && "Could not allocate target machine!");
 288   assert(mod && "Should have exited after outputting help!");
 289   TargetMachine &Target = *target.get();
 290
 291   if (DisableDotLoc)
 292     Target.setMCUseLoc(false);
 293
 294   if (DisableCFI)
 295     Target.setMCUseCFI(false);
 296
 297   if (EnableDwarfDirectory)
 298     Target.setMCUseDwarfDirectory(true);
 299
 300   if (GenerateSoftFloatCalls)
 301     FloatABIForCalls = FloatABI::Soft;
 302
 303   // Disable .loc support for older OS X versions.
 304   if (TheTriple.isMacOSX() &&
 305       TheTriple.isMacOSXVersionLT(10, 6))
 306     Target.setMCUseLoc(false);
 307
 308   // Figure out where we are going to send the output.
 309   OwningPtr<tool_output_file> Out
 310     (GetOutputStream(TheTarget->getName(), TheTriple.getOS(), argv[0]));
 311   if (!Out) return 1;
 312
 313   // Build up all of the passes that we want to do to the module.
 314   PassManager PM;
 315
 316   // Add an appropriate TargetLibraryInfo pass for the module's triple.
 317   TargetLibraryInfo *TLI = new TargetLibraryInfo(TheTriple);
 318   if (DisableSimplifyLibCalls)
 319     TLI->disableAllFunctions();
 320   PM.add(TLI);
 321
 322   // Add intenal analysis passes from the target machine.
 323   Target.addAnalysisPasses(PM);
 324
 325   // Add the target data from the target machine, if it exists, or the module.
 326   if (const DataLayout *TD = Target.getDataLayout())
 327     PM.add(new DataLayout(*TD));
 328   else
 329     PM.add(new DataLayout(mod));
 330
 331   // Override default to generate verbose assembly.
 332   Target.setAsmVerbosityDefault(true);
 333
 334   if (RelaxAll) {
 335     if (FileType != TargetMachine::CGFT_ObjectFile)
 336       errs() << argv[0]
 337              << ": warning: ignoring -mc-relax-all because filetype != obj";
 338     else
 339       Target.setMCRelaxAll(true);
 340   }
 341
 342   {
 343     formatted_raw_ostream FOS(Out->os());
 344
 345     AnalysisID StartAfterID = 0;
 346     AnalysisID StopAfterID = 0;
 347     const PassRegistry *PR = PassRegistry::getPassRegistry();
 348     if (!StartAfter.empty()) {
 349       const PassInfo *PI = PR->getPassInfo(StartAfter);
 350       if (!PI) {
 351         errs() << argv[0] << ": start-after pass is not registered.\n";
 352         return 1;
 353       }
 354       StartAfterID = PI->getTypeInfo();
 355     }
 356     if (!StopAfter.empty()) {
 357       const PassInfo *PI = PR->getPassInfo(StopAfter);
 358       if (!PI) {
 359         errs() << argv[0] << ": stop-after pass is not registered.\n";
 360         return 1;
 361       }
 362       StopAfterID = PI->getTypeInfo();
 363     }
 364
 365     // Ask the target to add backend passes as necessary.
 366     if (Target.addPassesToEmitFile(PM, FOS, FileType, NoVerify,
 367                                    StartAfterID, StopAfterID)) {
 368       errs() << argv[0] << ": target does not support generation of this"
 369              << " file type!\n";
 370       return 1;
 371     }
 372
 373     // Before executing passes, print the final values of the LLVM options.
 374     cl::PrintOptionValues();
 375
 376     PM.run(*mod);
 377   }
 378
 379   // Declare success.
 380   Out->keep();
 381
 382   return 0;
 383 }