llc.cpp revision 327952 
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/ADT/STLExtras.h"
17#include "llvm/ADT/Triple.h"
18#include "llvm/Analysis/TargetLibraryInfo.h"
19#include "llvm/CodeGen/CommandFlags.def"
20#include "llvm/CodeGen/LinkAllAsmWriterComponents.h"
21#include "llvm/CodeGen/LinkAllCodegenComponents.h"
22#include "llvm/CodeGen/MIRParser/MIRParser.h"
23#include "llvm/CodeGen/MachineFunctionPass.h"
24#include "llvm/CodeGen/MachineModuleInfo.h"
25#include "llvm/CodeGen/TargetPassConfig.h"
26#include "llvm/CodeGen/TargetSubtargetInfo.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/Transforms/Utils/Cloning.h"
53#include <memory>
54using namespace llvm;
55
56// General options for llc.  Other pass-specific options are specified
57// within the corresponding llc passes, and target-specific options
58// and back-end code generation options are specified with the target machine.
59//
60static cl::opt<std::string>
61InputFilename(cl::Positional, cl::desc("<input bitcode>"), cl::init("-"));
62
63static cl::opt<std::string>
64InputLanguage("x", cl::desc("Input language ('ir' or 'mir')"));
65
66static cl::opt<std::string>
67OutputFilename("o", cl::desc("Output filename"), cl::value_desc("filename"));
68
69static cl::opt<unsigned>
70TimeCompilations("time-compilations", cl::Hidden, cl::init(1u),
71                 cl::value_desc("N"),
72                 cl::desc("Repeat compilation N times for timing"));
73
74static cl::opt<bool>
75NoIntegratedAssembler("no-integrated-as", cl::Hidden,
76                      cl::desc("Disable integrated assembler"));
77
78static cl::opt<bool>
79    PreserveComments("preserve-as-comments", cl::Hidden,
80                     cl::desc("Preserve Comments in outputted assembly"),
81                     cl::init(true));
82
83// Determine optimization level.
84static cl::opt<char>
85OptLevel("O",
86         cl::desc("Optimization level. [-O0, -O1, -O2, or -O3] "
87                  "(default = '-O2')"),
88         cl::Prefix,
89         cl::ZeroOrMore,
90         cl::init(' '));
91
92static cl::opt<std::string>
93TargetTriple("mtriple", cl::desc("Override target triple for module"));
94
95static cl::opt<std::string> SplitDwarfFile(
96    "split-dwarf-file",
97    cl::desc(
98        "Specify the name of the .dwo file to encode in the DWARF output"));
99
100static cl::opt<bool> NoVerify("disable-verify", cl::Hidden,
101                              cl::desc("Do not verify input module"));
102
103static cl::opt<bool> DisableSimplifyLibCalls("disable-simplify-libcalls",
104                                             cl::desc("Disable simplify-libcalls"));
105
106static cl::opt<bool> ShowMCEncoding("show-mc-encoding", cl::Hidden,
107                                    cl::desc("Show encoding in .s output"));
108
109static cl::opt<bool> EnableDwarfDirectory(
110    "enable-dwarf-directory", cl::Hidden,
111    cl::desc("Use .file directives with an explicit directory."));
112
113static cl::opt<bool> AsmVerbose("asm-verbose",
114                                cl::desc("Add comments to directives."),
115                                cl::init(true));
116
117static cl::opt<bool>
118    CompileTwice("compile-twice", cl::Hidden,
119                 cl::desc("Run everything twice, re-using the same pass "
120                          "manager and verify the result is the same."),
121                 cl::init(false));
122
123static cl::opt<bool> DiscardValueNames(
124    "discard-value-names",
125    cl::desc("Discard names from Value (other than GlobalValue)."),
126    cl::init(false), cl::Hidden);
127
128static cl::list<std::string> IncludeDirs("I", cl::desc("include search path"));
129
130static cl::opt<bool> PassRemarksWithHotness(
131    "pass-remarks-with-hotness",
132    cl::desc("With PGO, include profile count in optimization remarks"),
133    cl::Hidden);
134
135static cl::opt<unsigned> PassRemarksHotnessThreshold(
136    "pass-remarks-hotness-threshold",
137    cl::desc("Minimum profile count required for an optimization remark to be output"),
138    cl::Hidden);
139
140static cl::opt<std::string>
141    RemarksFilename("pass-remarks-output",
142                    cl::desc("YAML output filename for pass remarks"),
143                    cl::value_desc("filename"));
144
145namespace {
146static ManagedStatic<std::vector<std::string>> RunPassNames;
147
148struct RunPassOption {
149  void operator=(const std::string &Val) const {
150    if (Val.empty())
151      return;
152    SmallVector<StringRef, 8> PassNames;
153    StringRef(Val).split(PassNames, ',', -1, false);
154    for (auto PassName : PassNames)
155      RunPassNames->push_back(PassName);
156  }
157};
158}
159
160static RunPassOption RunPassOpt;
161
162static cl::opt<RunPassOption, true, cl::parser<std::string>> RunPass(
163    "run-pass",
164    cl::desc("Run compiler only for specified passes (comma separated list)"),
165    cl::value_desc("pass-name"), cl::ZeroOrMore, cl::location(RunPassOpt));
166
167static int compileModule(char **, LLVMContext &);
168
169static std::unique_ptr<ToolOutputFile> GetOutputStream(const char *TargetName,
170                                                       Triple::OSType OS,
171                                                       const char *ProgName) {
172  // If we don't yet have an output filename, make one.
173  if (OutputFilename.empty()) {
174    if (InputFilename == "-")
175      OutputFilename = "-";
176    else {
177      // If InputFilename ends in .bc or .ll, remove it.
178      StringRef IFN = InputFilename;
179      if (IFN.endswith(".bc") || IFN.endswith(".ll"))
180        OutputFilename = IFN.drop_back(3);
181      else if (IFN.endswith(".mir"))
182        OutputFilename = IFN.drop_back(4);
183      else
184        OutputFilename = IFN;
185
186      switch (FileType) {
187      case TargetMachine::CGFT_AssemblyFile:
188        if (TargetName[0] == 'c') {
189          if (TargetName[1] == 0)
190            OutputFilename += ".cbe.c";
191          else if (TargetName[1] == 'p' && TargetName[2] == 'p')
192            OutputFilename += ".cpp";
193          else
194            OutputFilename += ".s";
195        } else
196          OutputFilename += ".s";
197        break;
198      case TargetMachine::CGFT_ObjectFile:
199        if (OS == Triple::Win32)
200          OutputFilename += ".obj";
201        else
202          OutputFilename += ".o";
203        break;
204      case TargetMachine::CGFT_Null:
205        OutputFilename += ".null";
206        break;
207      }
208    }
209  }
210
211  // Decide if we need "binary" output.
212  bool Binary = false;
213  switch (FileType) {
214  case TargetMachine::CGFT_AssemblyFile:
215    break;
216  case TargetMachine::CGFT_ObjectFile:
217  case TargetMachine::CGFT_Null:
218    Binary = true;
219    break;
220  }
221
222  // Open the file.
223  std::error_code EC;
224  sys::fs::OpenFlags OpenFlags = sys::fs::F_None;
225  if (!Binary)
226    OpenFlags |= sys::fs::F_Text;
227  auto FDOut = llvm::make_unique<ToolOutputFile>(OutputFilename, EC, OpenFlags);
228  if (EC) {
229    errs() << EC.message() << '\n';
230    return nullptr;
231  }
232
233  return FDOut;
234}
235
236struct LLCDiagnosticHandler : public DiagnosticHandler {
237  bool *HasError;
238  LLCDiagnosticHandler(bool *HasErrorPtr) : HasError(HasErrorPtr) {}
239  bool handleDiagnostics(const DiagnosticInfo &DI) override {
240    if (DI.getSeverity() == DS_Error)
241      *HasError = true;
242
243    if (auto *Remark = dyn_cast<DiagnosticInfoOptimizationBase>(&DI))
244      if (!Remark->isEnabled())
245        return true;
246
247    DiagnosticPrinterRawOStream DP(errs());
248    errs() << LLVMContext::getDiagnosticMessagePrefix(DI.getSeverity()) << ": ";
249    DI.print(DP);
250    errs() << "\n";
251    return true;
252  }
253};
254
255static void InlineAsmDiagHandler(const SMDiagnostic &SMD, void *Context,
256                                 unsigned LocCookie) {
257  bool *HasError = static_cast<bool *>(Context);
258  if (SMD.getKind() == SourceMgr::DK_Error)
259    *HasError = true;
260
261  SMD.print(nullptr, errs());
262
263  // For testing purposes, we print the LocCookie here.
264  if (LocCookie)
265    errs() << "note: !srcloc = " << LocCookie << "\n";
266}
267
268// main - Entry point for the llc compiler.
269//
270int main(int argc, char **argv) {
271  sys::PrintStackTraceOnErrorSignal(argv[0]);
272  PrettyStackTraceProgram X(argc, argv);
273
274  // Enable debug stream buffering.
275  EnableDebugBuffering = true;
276
277  LLVMContext Context;
278  llvm_shutdown_obj Y;  // Call llvm_shutdown() on exit.
279
280  // Initialize targets first, so that --version shows registered targets.
281  InitializeAllTargets();
282  InitializeAllTargetMCs();
283  InitializeAllAsmPrinters();
284  InitializeAllAsmParsers();
285
286  // Initialize codegen and IR passes used by llc so that the -print-after,
287  // -print-before, and -stop-after options work.
288  PassRegistry *Registry = PassRegistry::getPassRegistry();
289  initializeCore(*Registry);
290  initializeCodeGen(*Registry);
291  initializeLoopStrengthReducePass(*Registry);
292  initializeLowerIntrinsicsPass(*Registry);
293  initializeEntryExitInstrumenterPass(*Registry);
294  initializePostInlineEntryExitInstrumenterPass(*Registry);
295  initializeUnreachableBlockElimLegacyPassPass(*Registry);
296  initializeConstantHoistingLegacyPassPass(*Registry);
297  initializeScalarOpts(*Registry);
298  initializeVectorization(*Registry);
299  initializeScalarizeMaskedMemIntrinPass(*Registry);
300  initializeExpandReductionsPass(*Registry);
301
302  // Initialize debugging passes.
303  initializeScavengerTestPass(*Registry);
304
305  // Register the target printer for --version.
306  cl::AddExtraVersionPrinter(TargetRegistry::printRegisteredTargetsForVersion);
307
308  cl::ParseCommandLineOptions(argc, argv, "llvm system compiler\n");
309
310  Context.setDiscardValueNames(DiscardValueNames);
311
312  // Set a diagnostic handler that doesn't exit on the first error
313  bool HasError = false;
314  Context.setDiagnosticHandler(
315      llvm::make_unique<LLCDiagnosticHandler>(&HasError));
316  Context.setInlineAsmDiagnosticHandler(InlineAsmDiagHandler, &HasError);
317
318  if (PassRemarksWithHotness)
319    Context.setDiagnosticsHotnessRequested(true);
320
321  if (PassRemarksHotnessThreshold)
322    Context.setDiagnosticsHotnessThreshold(PassRemarksHotnessThreshold);
323
324  std::unique_ptr<ToolOutputFile> YamlFile;
325  if (RemarksFilename != "") {
326    std::error_code EC;
327    YamlFile =
328        llvm::make_unique<ToolOutputFile>(RemarksFilename, EC, sys::fs::F_None);
329    if (EC) {
330      errs() << EC.message() << '\n';
331      return 1;
332    }
333    Context.setDiagnosticsOutputFile(
334        llvm::make_unique<yaml::Output>(YamlFile->os()));
335  }
336
337  if (InputLanguage != "" && InputLanguage != "ir" &&
338      InputLanguage != "mir") {
339    errs() << argv[0] << "Input language must be '', 'IR' or 'MIR'\n";
340    return 1;
341  }
342
343  // Compile the module TimeCompilations times to give better compile time
344  // metrics.
345  for (unsigned I = TimeCompilations; I; --I)
346    if (int RetVal = compileModule(argv, Context))
347      return RetVal;
348
349  if (YamlFile)
350    YamlFile->keep();
351  return 0;
352}
353
354static bool addPass(PassManagerBase &PM, const char *argv0,
355                    StringRef PassName, TargetPassConfig &TPC) {
356  if (PassName == "none")
357    return false;
358
359  const PassRegistry *PR = PassRegistry::getPassRegistry();
360  const PassInfo *PI = PR->getPassInfo(PassName);
361  if (!PI) {
362    errs() << argv0 << ": run-pass " << PassName << " is not registered.\n";
363    return true;
364  }
365
366  Pass *P;
367  if (PI->getNormalCtor())
368    P = PI->getNormalCtor()();
369  else {
370    errs() << argv0 << ": cannot create pass: " << PI->getPassName() << "\n";
371    return true;
372  }
373  std::string Banner = std::string("After ") + std::string(P->getPassName());
374  PM.add(P);
375  TPC.printAndVerify(Banner);
376
377  return false;
378}
379
380static int compileModule(char **argv, LLVMContext &Context) {
381  // Load the module to be compiled...
382  SMDiagnostic Err;
383  std::unique_ptr<Module> M;
384  std::unique_ptr<MIRParser> MIR;
385  Triple TheTriple;
386
387  bool SkipModule = MCPU == "help" ||
388                    (!MAttrs.empty() && MAttrs.front() == "help");
389
390  // If user just wants to list available options, skip module loading
391  if (!SkipModule) {
392    if (InputLanguage == "mir" ||
393        (InputLanguage == "" && StringRef(InputFilename).endswith(".mir"))) {
394      MIR = createMIRParserFromFile(InputFilename, Err, Context);
395      if (MIR)
396        M = MIR->parseIRModule();
397    } else
398      M = parseIRFile(InputFilename, Err, Context);
399    if (!M) {
400      Err.print(argv[0], errs());
401      return 1;
402    }
403
404    // Verify module immediately to catch problems before doInitialization() is
405    // called on any passes.
406    if (!NoVerify && verifyModule(*M, &errs())) {
407      errs() << argv[0] << ": " << InputFilename
408             << ": error: input module is broken!\n";
409      return 1;
410    }
411
412    // If we are supposed to override the target triple, do so now.
413    if (!TargetTriple.empty())
414      M->setTargetTriple(Triple::normalize(TargetTriple));
415    TheTriple = Triple(M->getTargetTriple());
416  } else {
417    TheTriple = Triple(Triple::normalize(TargetTriple));
418  }
419
420  if (TheTriple.getTriple().empty())
421    TheTriple.setTriple(sys::getDefaultTargetTriple());
422
423  // Get the target specific parser.
424  std::string Error;
425  const Target *TheTarget = TargetRegistry::lookupTarget(MArch, TheTriple,
426                                                         Error);
427  if (!TheTarget) {
428    errs() << argv[0] << ": " << Error;
429    return 1;
430  }
431
432  std::string CPUStr = getCPUStr(), FeaturesStr = getFeaturesStr();
433
434  CodeGenOpt::Level OLvl = CodeGenOpt::Default;
435  switch (OptLevel) {
436  default:
437    errs() << argv[0] << ": invalid optimization level.\n";
438    return 1;
439  case ' ': break;
440  case '0': OLvl = CodeGenOpt::None; break;
441  case '1': OLvl = CodeGenOpt::Less; break;
442  case '2': OLvl = CodeGenOpt::Default; break;
443  case '3': OLvl = CodeGenOpt::Aggressive; break;
444  }
445
446  TargetOptions Options = InitTargetOptionsFromCodeGenFlags();
447  Options.DisableIntegratedAS = NoIntegratedAssembler;
448  Options.MCOptions.ShowMCEncoding = ShowMCEncoding;
449  Options.MCOptions.MCUseDwarfDirectory = EnableDwarfDirectory;
450  Options.MCOptions.AsmVerbose = AsmVerbose;
451  Options.MCOptions.PreserveAsmComments = PreserveComments;
452  Options.MCOptions.IASSearchPaths = IncludeDirs;
453  Options.MCOptions.SplitDwarfFile = SplitDwarfFile;
454
455  std::unique_ptr<TargetMachine> Target(TheTarget->createTargetMachine(
456      TheTriple.getTriple(), CPUStr, FeaturesStr, Options, getRelocModel(),
457      getCodeModel(), OLvl));
458
459  assert(Target && "Could not allocate target machine!");
460
461  // If we don't have a module then just exit now. We do this down
462  // here since the CPU/Feature help is underneath the target machine
463  // creation.
464  if (SkipModule)
465    return 0;
466
467  assert(M && "Should have exited if we didn't have a module!");
468  if (FloatABIForCalls != FloatABI::Default)
469    Options.FloatABIType = FloatABIForCalls;
470
471  // Figure out where we are going to send the output.
472  std::unique_ptr<ToolOutputFile> Out =
473      GetOutputStream(TheTarget->getName(), TheTriple.getOS(), argv[0]);
474  if (!Out) return 1;
475
476  // Build up all of the passes that we want to do to the module.
477  legacy::PassManager PM;
478
479  // Add an appropriate TargetLibraryInfo pass for the module's triple.
480  TargetLibraryInfoImpl TLII(Triple(M->getTargetTriple()));
481
482  // The -disable-simplify-libcalls flag actually disables all builtin optzns.
483  if (DisableSimplifyLibCalls)
484    TLII.disableAllFunctions();
485  PM.add(new TargetLibraryInfoWrapperPass(TLII));
486
487  // Add the target data from the target machine, if it exists, or the module.
488  M->setDataLayout(Target->createDataLayout());
489
490  // Override function attributes based on CPUStr, FeaturesStr, and command line
491  // flags.
492  setFunctionAttributes(CPUStr, FeaturesStr, *M);
493
494  if (RelaxAll.getNumOccurrences() > 0 &&
495      FileType != TargetMachine::CGFT_ObjectFile)
496    errs() << argv[0]
497             << ": warning: ignoring -mc-relax-all because filetype != obj";
498
499  {
500    raw_pwrite_stream *OS = &Out->os();
501
502    // Manually do the buffering rather than using buffer_ostream,
503    // so we can memcmp the contents in CompileTwice mode
504    SmallVector<char, 0> Buffer;
505    std::unique_ptr<raw_svector_ostream> BOS;
506    if ((FileType != TargetMachine::CGFT_AssemblyFile &&
507         !Out->os().supportsSeeking()) ||
508        CompileTwice) {
509      BOS = make_unique<raw_svector_ostream>(Buffer);
510      OS = BOS.get();
511    }
512
513    const char *argv0 = argv[0];
514    LLVMTargetMachine &LLVMTM = static_cast<LLVMTargetMachine&>(*Target);
515    MachineModuleInfo *MMI = new MachineModuleInfo(&LLVMTM);
516
517    // Construct a custom pass pipeline that starts after instruction
518    // selection.
519    if (!RunPassNames->empty()) {
520      if (!MIR) {
521        errs() << argv0 << ": run-pass is for .mir file only.\n";
522        return 1;
523      }
524      TargetPassConfig &TPC = *LLVMTM.createPassConfig(PM);
525      if (TPC.hasLimitedCodeGenPipeline()) {
526        errs() << argv0 << ": run-pass cannot be used with "
527               << TPC.getLimitedCodeGenPipelineReason(" and ") << ".\n";
528        return 1;
529      }
530
531      TPC.setDisableVerify(NoVerify);
532      PM.add(&TPC);
533      PM.add(MMI);
534      TPC.printAndVerify("");
535      for (const std::string &RunPassName : *RunPassNames) {
536        if (addPass(PM, argv0, RunPassName, TPC))
537          return 1;
538      }
539      TPC.setInitialized();
540      PM.add(createPrintMIRPass(*OS));
541      PM.add(createFreeMachineFunctionPass());
542    } else if (Target->addPassesToEmitFile(PM, *OS, FileType, NoVerify, MMI)) {
543      errs() << argv0 << ": target does not support generation of this"
544             << " file type!\n";
545      return 1;
546    }
547
548    if (MIR) {
549      assert(MMI && "Forgot to create MMI?");
550      if (MIR->parseMachineFunctions(*M, *MMI))
551        return 1;
552    }
553
554    // Before executing passes, print the final values of the LLVM options.
555    cl::PrintOptionValues();
556
557    // If requested, run the pass manager over the same module again,
558    // to catch any bugs due to persistent state in the passes. Note that
559    // opt has the same functionality, so it may be worth abstracting this out
560    // in the future.
561    SmallVector<char, 0> CompileTwiceBuffer;
562    if (CompileTwice) {
563      std::unique_ptr<Module> M2(llvm::CloneModule(M.get()));
564      PM.run(*M2);
565      CompileTwiceBuffer = Buffer;
566      Buffer.clear();
567    }
568
569    PM.run(*M);
570
571    auto HasError =
572        ((const LLCDiagnosticHandler *)(Context.getDiagHandlerPtr()))->HasError;
573    if (*HasError)
574      return 1;
575
576    // Compare the two outputs and make sure they're the same
577    if (CompileTwice) {
578      if (Buffer.size() != CompileTwiceBuffer.size() ||
579          (memcmp(Buffer.data(), CompileTwiceBuffer.data(), Buffer.size()) !=
580           0)) {
581        errs()
582            << "Running the pass manager twice changed the output.\n"
583               "Writing the result of the second run to the specified output\n"
584               "To generate the one-run comparison binary, just run without\n"
585               "the compile-twice option\n";
586        Out->os() << Buffer;
587        Out->keep();
588        return 1;
589      }
590    }
591
592    if (BOS) {
593      Out->os() << Buffer;
594    }
595  }
596
597  // Declare success.
598  Out->keep();
599
600  return 0;
601}
602