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