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 17 #include "llvm/ADT/STLExtras.h" 18 #include "llvm/ADT/Triple.h" 19 #include "llvm/Analysis/TargetLibraryInfo.h" 20 #include "llvm/CodeGen/CommandFlags.h" 21 #include "llvm/CodeGen/LinkAllAsmWriterComponents.h" 22 #include "llvm/CodeGen/LinkAllCodegenComponents.h" 23 #include "llvm/CodeGen/MIRParser/MIRParser.h" 24 #include "llvm/CodeGen/MachineFunctionPass.h" 25 #include "llvm/CodeGen/MachineModuleInfo.h" 26 #include "llvm/CodeGen/TargetPassConfig.h" 27 #include "llvm/IR/DataLayout.h" 28 #include "llvm/IR/DiagnosticInfo.h" 29 #include "llvm/IR/DiagnosticPrinter.h" 30 #include "llvm/IR/IRPrintingPasses.h" 31 #include "llvm/IR/LLVMContext.h" 32 #include "llvm/IR/LegacyPassManager.h" 33 #include "llvm/IR/Module.h" 34 #include "llvm/IR/Verifier.h" 35 #include "llvm/IRReader/IRReader.h" 36 #include "llvm/MC/SubtargetFeature.h" 37 #include "llvm/Pass.h" 38 #include "llvm/Support/CommandLine.h" 39 #include "llvm/Support/Debug.h" 40 #include "llvm/Support/FileSystem.h" 41 #include "llvm/Support/FormattedStream.h" 42 #include "llvm/Support/Host.h" 43 #include "llvm/Support/ManagedStatic.h" 44 #include "llvm/Support/PluginLoader.h" 45 #include "llvm/Support/PrettyStackTrace.h" 46 #include "llvm/Support/Signals.h" 47 #include "llvm/Support/SourceMgr.h" 48 #include "llvm/Support/TargetRegistry.h" 49 #include "llvm/Support/TargetSelect.h" 50 #include "llvm/Support/ToolOutputFile.h" 51 #include "llvm/Target/TargetMachine.h" 52 #include "llvm/Target/TargetSubtargetInfo.h" 53 #include "llvm/Transforms/Utils/Cloning.h" 54 #include <memory> 55 using namespace llvm; 56 57 // General options for llc. Other pass-specific options are specified 58 // within the corresponding llc passes, and target-specific options 59 // and back-end code generation options are specified with the target machine. 60 // 61 static cl::opt<std::string> 62 InputFilename(cl::Positional, cl::desc("<input bitcode>"), cl::init("-")); 63 64 static cl::opt<std::string> 65 OutputFilename("o", cl::desc("Output filename"), cl::value_desc("filename")); 66 67 static cl::opt<unsigned> 68 TimeCompilations("time-compilations", cl::Hidden, cl::init(1u), 69 cl::value_desc("N"), 70 cl::desc("Repeat compilation N times for timing")); 71 72 static cl::opt<bool> 73 NoIntegratedAssembler("no-integrated-as", cl::Hidden, 74 cl::desc("Disable integrated assembler")); 75 76 static cl::opt<bool> 77 PreserveComments("preserve-as-comments", cl::Hidden, 78 cl::desc("Preserve Comments in outputted assembly"), 79 cl::init(true)); 80 81 // Determine optimization level. 82 static cl::opt<char> 83 OptLevel("O", 84 cl::desc("Optimization level. [-O0, -O1, -O2, or -O3] " 85 "(default = '-O2')"), 86 cl::Prefix, 87 cl::ZeroOrMore, 88 cl::init(' ')); 89 90 static cl::opt<std::string> 91 TargetTriple("mtriple", cl::desc("Override target triple for module")); 92 93 static cl::opt<bool> NoVerify("disable-verify", cl::Hidden, 94 cl::desc("Do not verify input module")); 95 96 static cl::opt<bool> DisableSimplifyLibCalls("disable-simplify-libcalls", 97 cl::desc("Disable simplify-libcalls")); 98 99 static cl::opt<bool> ShowMCEncoding("show-mc-encoding", cl::Hidden, 100 cl::desc("Show encoding in .s output")); 101 102 static cl::opt<bool> EnableDwarfDirectory( 103 "enable-dwarf-directory", cl::Hidden, 104 cl::desc("Use .file directives with an explicit directory.")); 105 106 static cl::opt<bool> AsmVerbose("asm-verbose", 107 cl::desc("Add comments to directives."), 108 cl::init(true)); 109 110 static cl::opt<bool> 111 CompileTwice("compile-twice", cl::Hidden, 112 cl::desc("Run everything twice, re-using the same pass " 113 "manager and verify the result is the same."), 114 cl::init(false)); 115 116 static cl::opt<bool> DiscardValueNames( 117 "discard-value-names", 118 cl::desc("Discard names from Value (other than GlobalValue)."), 119 cl::init(false), cl::Hidden); 120 121 namespace { 122 static ManagedStatic<std::vector<std::string>> RunPassNames; 123 124 struct RunPassOption { 125 void operator=(const std::string &Val) const { 126 if (Val.empty()) 127 return; 128 SmallVector<StringRef, 8> PassNames; 129 StringRef(Val).split(PassNames, ',', -1, false); 130 for (auto PassName : PassNames) 131 RunPassNames->push_back(PassName); 132 } 133 }; 134 } 135 136 static RunPassOption RunPassOpt; 137 138 static cl::opt<RunPassOption, true, cl::parser<std::string>> RunPass( 139 "run-pass", 140 cl::desc("Run compiler only for specified passes (comma separated list)"), 141 cl::value_desc("pass-name"), cl::ZeroOrMore, cl::location(RunPassOpt)); 142 143 static int compileModule(char **, LLVMContext &); 144 145 static std::unique_ptr<tool_output_file> 146 GetOutputStream(const char *TargetName, Triple::OSType OS, 147 const char *ProgName) { 148 // If we don't yet have an output filename, make one. 149 if (OutputFilename.empty()) { 150 if (InputFilename == "-") 151 OutputFilename = "-"; 152 else { 153 // If InputFilename ends in .bc or .ll, remove it. 154 StringRef IFN = InputFilename; 155 if (IFN.endswith(".bc") || IFN.endswith(".ll")) 156 OutputFilename = IFN.drop_back(3); 157 else if (IFN.endswith(".mir")) 158 OutputFilename = IFN.drop_back(4); 159 else 160 OutputFilename = IFN; 161 162 switch (FileType) { 163 case TargetMachine::CGFT_AssemblyFile: 164 if (TargetName[0] == 'c') { 165 if (TargetName[1] == 0) 166 OutputFilename += ".cbe.c"; 167 else if (TargetName[1] == 'p' && TargetName[2] == 'p') 168 OutputFilename += ".cpp"; 169 else 170 OutputFilename += ".s"; 171 } else 172 OutputFilename += ".s"; 173 break; 174 case TargetMachine::CGFT_ObjectFile: 175 if (OS == Triple::Win32) 176 OutputFilename += ".obj"; 177 else 178 OutputFilename += ".o"; 179 break; 180 case TargetMachine::CGFT_Null: 181 OutputFilename += ".null"; 182 break; 183 } 184 } 185 } 186 187 // Decide if we need "binary" output. 188 bool Binary = false; 189 switch (FileType) { 190 case TargetMachine::CGFT_AssemblyFile: 191 break; 192 case TargetMachine::CGFT_ObjectFile: 193 case TargetMachine::CGFT_Null: 194 Binary = true; 195 break; 196 } 197 198 // Open the file. 199 std::error_code EC; 200 sys::fs::OpenFlags OpenFlags = sys::fs::F_None; 201 if (!Binary) 202 OpenFlags |= sys::fs::F_Text; 203 auto FDOut = llvm::make_unique<tool_output_file>(OutputFilename, EC, 204 OpenFlags); 205 if (EC) { 206 errs() << EC.message() << '\n'; 207 return nullptr; 208 } 209 210 return FDOut; 211 } 212 213 static void DiagnosticHandler(const DiagnosticInfo &DI, void *Context) { 214 bool *HasError = static_cast<bool *>(Context); 215 if (DI.getSeverity() == DS_Error) 216 *HasError = true; 217 218 DiagnosticPrinterRawOStream DP(errs()); 219 errs() << LLVMContext::getDiagnosticMessagePrefix(DI.getSeverity()) << ": "; 220 DI.print(DP); 221 errs() << "\n"; 222 } 223 224 // main - Entry point for the llc compiler. 225 // 226 int main(int argc, char **argv) { 227 sys::PrintStackTraceOnErrorSignal(argv[0]); 228 PrettyStackTraceProgram X(argc, argv); 229 230 // Enable debug stream buffering. 231 EnableDebugBuffering = true; 232 233 LLVMContext Context; 234 llvm_shutdown_obj Y; // Call llvm_shutdown() on exit. 235 236 // Initialize targets first, so that --version shows registered targets. 237 InitializeAllTargets(); 238 InitializeAllTargetMCs(); 239 InitializeAllAsmPrinters(); 240 InitializeAllAsmParsers(); 241 242 // Initialize codegen and IR passes used by llc so that the -print-after, 243 // -print-before, and -stop-after options work. 244 PassRegistry *Registry = PassRegistry::getPassRegistry(); 245 initializeCore(*Registry); 246 initializeCodeGen(*Registry); 247 initializeLoopStrengthReducePass(*Registry); 248 initializeLowerIntrinsicsPass(*Registry); 249 initializeUnreachableBlockElimLegacyPassPass(*Registry); 250 251 // Register the target printer for --version. 252 cl::AddExtraVersionPrinter(TargetRegistry::printRegisteredTargetsForVersion); 253 254 cl::ParseCommandLineOptions(argc, argv, "llvm system compiler\n"); 255 256 Context.setDiscardValueNames(DiscardValueNames); 257 258 // Set a diagnostic handler that doesn't exit on the first error 259 bool HasError = false; 260 Context.setDiagnosticHandler(DiagnosticHandler, &HasError); 261 262 // Compile the module TimeCompilations times to give better compile time 263 // metrics. 264 for (unsigned I = TimeCompilations; I; --I) 265 if (int RetVal = compileModule(argv, Context)) 266 return RetVal; 267 return 0; 268 } 269 270 static int compileModule(char **argv, LLVMContext &Context) { 271 // Load the module to be compiled... 272 SMDiagnostic Err; 273 std::unique_ptr<Module> M; 274 std::unique_ptr<MIRParser> MIR; 275 Triple TheTriple; 276 277 bool SkipModule = MCPU == "help" || 278 (!MAttrs.empty() && MAttrs.front() == "help"); 279 280 // If user just wants to list available options, skip module loading 281 if (!SkipModule) { 282 if (StringRef(InputFilename).endswith_lower(".mir")) { 283 MIR = createMIRParserFromFile(InputFilename, Err, Context); 284 if (MIR) 285 M = MIR->parseLLVMModule(); 286 } else 287 M = parseIRFile(InputFilename, Err, Context); 288 if (!M) { 289 Err.print(argv[0], errs()); 290 return 1; 291 } 292 293 // Verify module immediately to catch problems before doInitialization() is 294 // called on any passes. 295 if (!NoVerify && verifyModule(*M, &errs())) { 296 errs() << argv[0] << ": " << InputFilename 297 << ": error: input module is broken!\n"; 298 return 1; 299 } 300 301 // If we are supposed to override the target triple, do so now. 302 if (!TargetTriple.empty()) 303 M->setTargetTriple(Triple::normalize(TargetTriple)); 304 TheTriple = Triple(M->getTargetTriple()); 305 } else { 306 TheTriple = Triple(Triple::normalize(TargetTriple)); 307 } 308 309 if (TheTriple.getTriple().empty()) 310 TheTriple.setTriple(sys::getDefaultTargetTriple()); 311 312 // Get the target specific parser. 313 std::string Error; 314 const Target *TheTarget = TargetRegistry::lookupTarget(MArch, TheTriple, 315 Error); 316 if (!TheTarget) { 317 errs() << argv[0] << ": " << Error; 318 return 1; 319 } 320 321 std::string CPUStr = getCPUStr(), FeaturesStr = getFeaturesStr(); 322 323 CodeGenOpt::Level OLvl = CodeGenOpt::Default; 324 switch (OptLevel) { 325 default: 326 errs() << argv[0] << ": invalid optimization level.\n"; 327 return 1; 328 case ' ': break; 329 case '0': OLvl = CodeGenOpt::None; break; 330 case '1': OLvl = CodeGenOpt::Less; break; 331 case '2': OLvl = CodeGenOpt::Default; break; 332 case '3': OLvl = CodeGenOpt::Aggressive; break; 333 } 334 335 TargetOptions Options = InitTargetOptionsFromCodeGenFlags(); 336 Options.DisableIntegratedAS = NoIntegratedAssembler; 337 Options.MCOptions.ShowMCEncoding = ShowMCEncoding; 338 Options.MCOptions.MCUseDwarfDirectory = EnableDwarfDirectory; 339 Options.MCOptions.AsmVerbose = AsmVerbose; 340 Options.MCOptions.PreserveAsmComments = PreserveComments; 341 342 std::unique_ptr<TargetMachine> Target( 343 TheTarget->createTargetMachine(TheTriple.getTriple(), CPUStr, FeaturesStr, 344 Options, getRelocModel(), CMModel, OLvl)); 345 346 assert(Target && "Could not allocate target machine!"); 347 348 // If we don't have a module then just exit now. We do this down 349 // here since the CPU/Feature help is underneath the target machine 350 // creation. 351 if (SkipModule) 352 return 0; 353 354 assert(M && "Should have exited if we didn't have a module!"); 355 if (FloatABIForCalls != FloatABI::Default) 356 Options.FloatABIType = FloatABIForCalls; 357 358 // Figure out where we are going to send the output. 359 std::unique_ptr<tool_output_file> Out = 360 GetOutputStream(TheTarget->getName(), TheTriple.getOS(), argv[0]); 361 if (!Out) return 1; 362 363 // Build up all of the passes that we want to do to the module. 364 legacy::PassManager PM; 365 366 // Add an appropriate TargetLibraryInfo pass for the module's triple. 367 TargetLibraryInfoImpl TLII(Triple(M->getTargetTriple())); 368 369 // The -disable-simplify-libcalls flag actually disables all builtin optzns. 370 if (DisableSimplifyLibCalls) 371 TLII.disableAllFunctions(); 372 PM.add(new TargetLibraryInfoWrapperPass(TLII)); 373 374 // Add the target data from the target machine, if it exists, or the module. 375 M->setDataLayout(Target->createDataLayout()); 376 377 // Override function attributes based on CPUStr, FeaturesStr, and command line 378 // flags. 379 setFunctionAttributes(CPUStr, FeaturesStr, *M); 380 381 if (RelaxAll.getNumOccurrences() > 0 && 382 FileType != TargetMachine::CGFT_ObjectFile) 383 errs() << argv[0] 384 << ": warning: ignoring -mc-relax-all because filetype != obj"; 385 386 { 387 raw_pwrite_stream *OS = &Out->os(); 388 389 // Manually do the buffering rather than using buffer_ostream, 390 // so we can memcmp the contents in CompileTwice mode 391 SmallVector<char, 0> Buffer; 392 std::unique_ptr<raw_svector_ostream> BOS; 393 if ((FileType != TargetMachine::CGFT_AssemblyFile && 394 !Out->os().supportsSeeking()) || 395 CompileTwice) { 396 BOS = make_unique<raw_svector_ostream>(Buffer); 397 OS = BOS.get(); 398 } 399 400 AnalysisID StartBeforeID = nullptr; 401 AnalysisID StartAfterID = nullptr; 402 AnalysisID StopAfterID = nullptr; 403 const PassRegistry *PR = PassRegistry::getPassRegistry(); 404 if (!RunPassNames->empty()) { 405 if (!StartAfter.empty() || !StopAfter.empty()) { 406 errs() << argv[0] << ": start-after and/or stop-after passes are " 407 "redundant when run-pass is specified.\n"; 408 return 1; 409 } 410 if (!MIR) { 411 errs() << argv[0] << ": run-pass needs a .mir input.\n"; 412 return 1; 413 } 414 LLVMTargetMachine &LLVMTM = static_cast<LLVMTargetMachine&>(*Target); 415 TargetPassConfig *TPC = LLVMTM.createPassConfig(PM); 416 PM.add(TPC); 417 LLVMTM.addMachineModuleInfo(PM); 418 LLVMTM.addMachineFunctionAnalysis(PM, MIR.get()); 419 TPC->printAndVerify(""); 420 421 for (std::string &RunPassName : *RunPassNames) { 422 const PassInfo *PI = PR->getPassInfo(RunPassName); 423 if (!PI) { 424 errs() << argv[0] << ": run-pass " << RunPassName << " is not registered.\n"; 425 return 1; 426 } 427 428 Pass *P; 429 if (PI->getTargetMachineCtor()) 430 P = PI->getTargetMachineCtor()(Target.get()); 431 else if (PI->getNormalCtor()) 432 P = PI->getNormalCtor()(); 433 else { 434 errs() << argv[0] << ": cannot create pass: " 435 << PI->getPassName() << "\n"; 436 return 1; 437 } 438 std::string Banner 439 = std::string("After ") + std::string(P->getPassName()); 440 PM.add(P); 441 TPC->printAndVerify(Banner); 442 } 443 PM.add(createPrintMIRPass(*OS)); 444 } else { 445 if (!StartAfter.empty()) { 446 const PassInfo *PI = PR->getPassInfo(StartAfter); 447 if (!PI) { 448 errs() << argv[0] << ": start-after pass is not registered.\n"; 449 return 1; 450 } 451 StartAfterID = PI->getTypeInfo(); 452 } 453 if (!StopAfter.empty()) { 454 const PassInfo *PI = PR->getPassInfo(StopAfter); 455 if (!PI) { 456 errs() << argv[0] << ": stop-after pass is not registered.\n"; 457 return 1; 458 } 459 StopAfterID = PI->getTypeInfo(); 460 } 461 462 // Ask the target to add backend passes as necessary. 463 if (Target->addPassesToEmitFile(PM, *OS, FileType, NoVerify, 464 StartBeforeID, StartAfterID, StopAfterID, 465 MIR.get())) { 466 errs() << argv[0] << ": target does not support generation of this" 467 << " file type!\n"; 468 return 1; 469 } 470 } 471 472 // Before executing passes, print the final values of the LLVM options. 473 cl::PrintOptionValues(); 474 475 // If requested, run the pass manager over the same module again, 476 // to catch any bugs due to persistent state in the passes. Note that 477 // opt has the same functionality, so it may be worth abstracting this out 478 // in the future. 479 SmallVector<char, 0> CompileTwiceBuffer; 480 if (CompileTwice) { 481 std::unique_ptr<Module> M2(llvm::CloneModule(M.get())); 482 PM.run(*M2); 483 CompileTwiceBuffer = Buffer; 484 Buffer.clear(); 485 } 486 487 PM.run(*M); 488 489 auto HasError = *static_cast<bool *>(Context.getDiagnosticContext()); 490 if (HasError) 491 return 1; 492 493 // Compare the two outputs and make sure they're the same 494 if (CompileTwice) { 495 if (Buffer.size() != CompileTwiceBuffer.size() || 496 (memcmp(Buffer.data(), CompileTwiceBuffer.data(), Buffer.size()) != 497 0)) { 498 errs() 499 << "Running the pass manager twice changed the output.\n" 500 "Writing the result of the second run to the specified output\n" 501 "To generate the one-run comparison binary, just run without\n" 502 "the compile-twice option\n"; 503 Out->os() << Buffer; 504 Out->keep(); 505 return 1; 506 } 507 } 508 509 if (BOS) { 510 Out->os() << Buffer; 511 } 512 } 513 514 // Declare success. 515 Out->keep(); 516 517 return 0; 518 } 519