tools/llc/llc.cpp

   1 //===-- llc.cpp - Implement the LLVM Native Code Generator ----------------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file was developed by the LLVM research group and is distributed under
   6 // the University of Illinois Open Source 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/Target/SubtargetFeature.h"
  20 #include "llvm/Target/TargetData.h"
  21 #include "llvm/Target/TargetMachine.h"
  22 #include "llvm/Target/TargetMachineRegistry.h"
  23 #include "llvm/Transforms/Scalar.h"
  24 #include "llvm/Module.h"
  25 #include "llvm/ModuleProvider.h"
  26 #include "llvm/PassManager.h"
  27 #include "llvm/Pass.h"
  28 #include "llvm/Support/CommandLine.h"
  29 #include "llvm/Support/ManagedStatic.h"
  30 #include "llvm/Support/MemoryBuffer.h"
  31 #include "llvm/Support/PluginLoader.h"
  32 #include "llvm/Support/FileUtilities.h"
  33 #include "llvm/Analysis/Verifier.h"
  34 #include "llvm/System/Signals.h"
  35 #include "llvm/Config/config.h"
  36 #include "llvm/LinkAllVMCore.h"
  37 #include <fstream>
  38 #include <iostream>
  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 static cl::opt<bool> Force("f", cl::desc("Overwrite output files"));
  53
  54 static cl::opt<bool> Fast("fast",
  55       cl::desc("Generate code quickly, potentially sacrificing code quality"));
  56
  57 static cl::opt<std::string>
  58 TargetTriple("mtriple", cl::desc("Override target triple for module"));
  59
  60 static cl::opt<const TargetMachineRegistry::Entry*, false, TargetNameParser>
  61 MArch("march", cl::desc("Architecture to generate code for:"));
  62
  63 static cl::opt<std::string>
  64 MCPU("mcpu",
  65   cl::desc("Target a specific cpu type (-mcpu=help for details)"),
  66   cl::value_desc("cpu-name"),
  67   cl::init(""));
  68
  69 static cl::list<std::string>
  70 MAttrs("mattr",
  71   cl::CommaSeparated,
  72   cl::desc("Target specific attributes (-mattr=help for details)"),
  73   cl::value_desc("a1,+a2,-a3,..."));
  74
  75 cl::opt<TargetMachine::CodeGenFileType>
  76 FileType("filetype", cl::init(TargetMachine::AssemblyFile),
  77   cl::desc("Choose a file type (not all types are supported by all targets):"),
  78   cl::values(
  79        clEnumValN(TargetMachine::AssemblyFile,    "asm",
  80                   "  Emit an assembly ('.s') file"),
  81        clEnumValN(TargetMachine::ObjectFile,    "obj",
  82                   "  Emit a native object ('.o') file [experimental]"),
  83        clEnumValN(TargetMachine::DynamicLibrary, "dynlib",
  84                   "  Emit a native dynamic library ('.so') file"
  85                   " [experimental]"),
  86        clEnumValEnd));
  87
  88 cl::opt<bool> NoVerify("disable-verify", cl::Hidden,
  89                        cl::desc("Do not verify input module"));
  90
  91
  92 // GetFileNameRoot - Helper function to get the basename of a filename.
  93 static inline std::string
  94 GetFileNameRoot(const std::string &InputFilename) {
  95   std::string IFN = InputFilename;
  96   std::string outputFilename;
  97   int Len = IFN.length();
  98   if ((Len > 2) &&
  99       IFN[Len-3] == '.' && IFN[Len-2] == 'b' && IFN[Len-1] == 'c') {
 100     outputFilename = std::string(IFN.begin(), IFN.end()-3); // s/.bc/.s/
 101   } else {
 102     outputFilename = IFN;
 103   }
 104   return outputFilename;
 105 }
 106
 107 static std::ostream *GetOutputStream(const char *ProgName) {
 108   if (OutputFilename != "") {
 109     if (OutputFilename == "-")
 110       return &std::cout;
 111
 112     // Specified an output filename?
 113     if (!Force && std::ifstream(OutputFilename.c_str())) {
 114       // If force is not specified, make sure not to overwrite a file!
 115       std::cerr << ProgName << ": error opening '" << OutputFilename
 116                 << "': file exists!\n"
 117                 << "Use -f command line argument to force output\n";
 118       return 0;
 119     }
 120     // Make sure that the Out file gets unlinked from the disk if we get a
 121     // SIGINT
 122     sys::RemoveFileOnSignal(sys::Path(OutputFilename));
 123
 124     return new std::ofstream(OutputFilename.c_str());
 125   }
 126
 127   if (InputFilename == "-") {
 128     OutputFilename = "-";
 129     return &std::cout;
 130   }
 131
 132   OutputFilename = GetFileNameRoot(InputFilename);
 133
 134   switch (FileType) {
 135   case TargetMachine::AssemblyFile:
 136     if (MArch->Name[0] != 'c' || MArch->Name[1] != 0)  // not CBE
 137       OutputFilename += ".s";
 138     else
 139       OutputFilename += ".cbe.c";
 140     break;
 141   case TargetMachine::ObjectFile:
 142     OutputFilename += ".o";
 143     break;
 144   case TargetMachine::DynamicLibrary:
 145     OutputFilename += LTDL_SHLIB_EXT;
 146     break;
 147   }
 148
 149   if (!Force && std::ifstream(OutputFilename.c_str())) {
 150     // If force is not specified, make sure not to overwrite a file!
 151     std::cerr << ProgName << ": error opening '" << OutputFilename
 152                           << "': file exists!\n"
 153                           << "Use -f command line argument to force output\n";
 154     return 0;
 155   }
 156
 157   // Make sure that the Out file gets unlinked from the disk if we get a
 158   // SIGINT
 159   sys::RemoveFileOnSignal(sys::Path(OutputFilename));
 160
 161   std::ostream *Out = new std::ofstream(OutputFilename.c_str());
 162   if (!Out->good()) {
 163     std::cerr << ProgName << ": error opening " << OutputFilename << "!\n";
 164     delete Out;
 165     return 0;
 166   }
 167
 168   return Out;
 169 }
 170
 171 // main - Entry point for the llc compiler.
 172 //
 173 int main(int argc, char **argv) {
 174   llvm_shutdown_obj X;  // Call llvm_shutdown() on exit.
 175   cl::ParseCommandLineOptions(argc, argv, " llvm system compiler\n");
 176   sys::PrintStackTraceOnErrorSignal();
 177
 178   // Load the module to be compiled...
 179   std::string ErrorMessage;
 180   std::auto_ptr<Module> M;
 181
 182   std::auto_ptr<MemoryBuffer> Buffer(
 183                    MemoryBuffer::getFileOrSTDIN(InputFilename, &ErrorMessage));
 184   if (Buffer.get())
 185     M.reset(ParseBitcodeFile(Buffer.get(), &ErrorMessage));
 186   if (M.get() == 0) {
 187     std::cerr << argv[0] << ": bitcode didn't read correctly.\n";
 188     std::cerr << "Reason: " << ErrorMessage << "\n";
 189     return 1;
 190   }
 191   Module &mod = *M.get();
 192
 193   // If we are supposed to override the target triple, do so now.
 194   if (!TargetTriple.empty())
 195     mod.setTargetTriple(TargetTriple);
 196
 197   // Allocate target machine.  First, check whether the user has
 198   // explicitly specified an architecture to compile for.
 199   if (MArch == 0) {
 200     std::string Err;
 201     MArch = TargetMachineRegistry::getClosestStaticTargetForModule(mod, Err);
 202     if (MArch == 0) {
 203       std::cerr << argv[0] << ": error auto-selecting target for module '"
 204                 << Err << "'.  Please use the -march option to explicitly "
 205                 << "pick a target.\n";
 206       return 1;
 207     }
 208   }
 209
 210   // Package up features to be passed to target/subtarget
 211   std::string FeaturesStr;
 212   if (MCPU.size() || MAttrs.size()) {
 213     SubtargetFeatures Features;
 214     Features.setCPU(MCPU);
 215     for (unsigned i = 0; i != MAttrs.size(); ++i)
 216       Features.AddFeature(MAttrs[i]);
 217     FeaturesStr = Features.getString();
 218   }
 219
 220   std::auto_ptr<TargetMachine> target(MArch->CtorFn(mod, FeaturesStr));
 221   assert(target.get() && "Could not allocate target machine!");
 222   TargetMachine &Target = *target.get();
 223
 224   // Figure out where we are going to send the output...
 225   std::ostream *Out = GetOutputStream(argv[0]);
 226   if (Out == 0) return 1;
 227
 228   // If this target requires addPassesToEmitWholeFile, do it now.  This is
 229   // used by strange things like the C backend.
 230   if (Target.WantsWholeFile()) {
 231     PassManager PM;
 232     PM.add(new TargetData(*Target.getTargetData()));
 233     if (!NoVerify)
 234       PM.add(createVerifierPass());
 235
 236     // Ask the target to add backend passes as necessary.
 237     if (Target.addPassesToEmitWholeFile(PM, *Out, FileType, Fast)) {
 238       std::cerr << argv[0] << ": target does not support generation of this"
 239                 << " file type!\n";
 240       if (Out != &std::cout) delete Out;
 241       // And the Out file is empty and useless, so remove it now.
 242       sys::Path(OutputFilename).eraseFromDisk();
 243       return 1;
 244     }
 245     PM.run(mod);
 246   } else {
 247     // Build up all of the passes that we want to do to the module.
 248     FunctionPassManager Passes(new ExistingModuleProvider(M.get()));
 249     Passes.add(new TargetData(*Target.getTargetData()));
 250
 251 #ifndef NDEBUG
 252     if (!NoVerify)
 253       Passes.add(createVerifierPass());
 254 #endif
 255
 256     // Ask the target to add backend passes as necessary.
 257     MachineCodeEmitter *MCE = 0;
 258
 259     switch (Target.addPassesToEmitFile(Passes, *Out, FileType, Fast)) {
 260     default:
 261       assert(0 && "Invalid file model!");
 262       return 1;
 263     case FileModel::Error:
 264       std::cerr << argv[0] << ": target does not support generation of this"
 265                 << " file type!\n";
 266       if (Out != &std::cout) delete Out;
 267       // And the Out file is empty and useless, so remove it now.
 268       sys::Path(OutputFilename).eraseFromDisk();
 269       return 1;
 270     case FileModel::AsmFile:
 271       break;
 272     case FileModel::MachOFile:
 273       MCE = AddMachOWriter(Passes, *Out, Target);
 274       break;
 275     case FileModel::ElfFile:
 276       MCE = AddELFWriter(Passes, *Out, Target);
 277       break;
 278     }
 279
 280     if (Target.addPassesToEmitFileFinish(Passes, MCE, Fast)) {
 281       std::cerr << argv[0] << ": target does not support generation of this"
 282                 << " file type!\n";
 283       if (Out != &std::cout) delete Out;
 284       // And the Out file is empty and useless, so remove it now.
 285       sys::Path(OutputFilename).eraseFromDisk();
 286       return 1;
 287     }
 288
 289     Passes.doInitialization();
 290
 291     // Run our queue of passes all at once now, efficiently.
 292     // TODO: this could lazily stream functions out of the module.
 293     for (Module::iterator I = mod.begin(), E = mod.end(); I != E; ++I)
 294       if (!I->isDeclaration())
 295         Passes.run(*I);
 296
 297     Passes.doFinalization();
 298   }
 299
 300   // Delete the ostream if it's not a stdout stream
 301   if (Out != &std::cout) delete Out;
 302
 303   return 0;
 304 }