llc.cpp revision 341825 
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.inc"
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/AutoUpgrade.h"
28#include "llvm/IR/DataLayout.h"
29#include "llvm/IR/DiagnosticInfo.h"
30#include "llvm/IR/DiagnosticPrinter.h"
31#include "llvm/IR/IRPrintingPasses.h"
32#include "llvm/IR/LLVMContext.h"
33#include "llvm/IR/LegacyPassManager.h"
34#include "llvm/IR/Module.h"
35#include "llvm/IR/Verifier.h"
36#include "llvm/IRReader/IRReader.h"
37#include "llvm/MC/SubtargetFeature.h"
38#include "llvm/Pass.h"
39#include "llvm/Support/CommandLine.h"
40#include "llvm/Support/Debug.h"
41#include "llvm/Support/FileSystem.h"
42#include "llvm/Support/FormattedStream.h"
43#include "llvm/Support/Host.h"
44#include "llvm/Support/InitLLVM.h"
45#include "llvm/Support/ManagedStatic.h"
46#include "llvm/Support/PluginLoader.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/Support/WithColor.h"
52#include "llvm/Target/TargetMachine.h"
53#include "llvm/Transforms/Utils/Cloning.h"
54#include <memory>
55using 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//
61static cl::opt<std::string>
62InputFilename(cl::Positional, cl::desc("<input bitcode>"), cl::init("-"));
63
64static cl::opt<std::string>
65InputLanguage("x", cl::desc("Input language ('ir' or 'mir')"));
66
67static cl::opt<std::string>
68OutputFilename("o", cl::desc("Output filename"), cl::value_desc("filename"));
69
70static cl::opt<std::string>
71    SplitDwarfOutputFile("split-dwarf-output",
72                         cl::desc(".dwo output filename"),
73                         cl::value_desc("filename"));
74
75static cl::opt<unsigned>
76TimeCompilations("time-compilations", cl::Hidden, cl::init(1u),
77                 cl::value_desc("N"),
78                 cl::desc("Repeat compilation N times for timing"));
79
80static cl::opt<bool>
81NoIntegratedAssembler("no-integrated-as", cl::Hidden,
82                      cl::desc("Disable integrated assembler"));
83
84static cl::opt<bool>
85    PreserveComments("preserve-as-comments", cl::Hidden,
86                     cl::desc("Preserve Comments in outputted assembly"),
87                     cl::init(true));
88
89// Determine optimization level.
90static cl::opt<char>
91OptLevel("O",
92         cl::desc("Optimization level. [-O0, -O1, -O2, or -O3] "
93                  "(default = '-O2')"),
94         cl::Prefix,
95         cl::ZeroOrMore,
96         cl::init(' '));
97
98static cl::opt<std::string>
99TargetTriple("mtriple", cl::desc("Override target triple for module"));
100
101static cl::opt<std::string> SplitDwarfFile(
102    "split-dwarf-file",
103    cl::desc(
104        "Specify the name of the .dwo file to encode in the DWARF output"));
105
106static cl::opt<bool> NoVerify("disable-verify", cl::Hidden,
107                              cl::desc("Do not verify input module"));
108
109static cl::opt<bool> DisableSimplifyLibCalls("disable-simplify-libcalls",
110                                             cl::desc("Disable simplify-libcalls"));
111
112static cl::opt<bool> ShowMCEncoding("show-mc-encoding", cl::Hidden,
113                                    cl::desc("Show encoding in .s output"));
114
115static cl::opt<bool> EnableDwarfDirectory(
116    "enable-dwarf-directory", cl::Hidden,
117    cl::desc("Use .file directives with an explicit directory."));
118
119static cl::opt<bool> AsmVerbose("asm-verbose",
120                                cl::desc("Add comments to directives."),
121                                cl::init(true));
122
123static cl::opt<bool>
124    CompileTwice("compile-twice", cl::Hidden,
125                 cl::desc("Run everything twice, re-using the same pass "
126                          "manager and verify the result is the same."),
127                 cl::init(false));
128
129static cl::opt<bool> DiscardValueNames(
130    "discard-value-names",
131    cl::desc("Discard names from Value (other than GlobalValue)."),
132    cl::init(false), cl::Hidden);
133
134static cl::list<std::string> IncludeDirs("I", cl::desc("include search path"));
135
136static cl::opt<bool> PassRemarksWithHotness(
137    "pass-remarks-with-hotness",
138    cl::desc("With PGO, include profile count in optimization remarks"),
139    cl::Hidden);
140
141static cl::opt<unsigned> PassRemarksHotnessThreshold(
142    "pass-remarks-hotness-threshold",
143    cl::desc("Minimum profile count required for an optimization remark to be output"),
144    cl::Hidden);
145
146static cl::opt<std::string>
147    RemarksFilename("pass-remarks-output",
148                    cl::desc("YAML output filename for pass remarks"),
149                    cl::value_desc("filename"));
150
151namespace {
152static ManagedStatic<std::vector<std::string>> RunPassNames;
153
154struct RunPassOption {
155  void operator=(const std::string &Val) const {
156    if (Val.empty())
157      return;
158    SmallVector<StringRef, 8> PassNames;
159    StringRef(Val).split(PassNames, ',', -1, false);
160    for (auto PassName : PassNames)
161      RunPassNames->push_back(PassName);
162  }
163};
164}
165
166static RunPassOption RunPassOpt;
167
168static cl::opt<RunPassOption, true, cl::parser<std::string>> RunPass(
169    "run-pass",
170    cl::desc("Run compiler only for specified passes (comma separated list)"),
171    cl::value_desc("pass-name"), cl::ZeroOrMore, cl::location(RunPassOpt));
172
173static int compileModule(char **, LLVMContext &);
174
175static std::unique_ptr<ToolOutputFile> GetOutputStream(const char *TargetName,
176                                                       Triple::OSType OS,
177                                                       const char *ProgName) {
178  // If we don't yet have an output filename, make one.
179  if (OutputFilename.empty()) {
180    if (InputFilename == "-")
181      OutputFilename = "-";
182    else {
183      // If InputFilename ends in .bc or .ll, remove it.
184      StringRef IFN = InputFilename;
185      if (IFN.endswith(".bc") || IFN.endswith(".ll"))
186        OutputFilename = IFN.drop_back(3);
187      else if (IFN.endswith(".mir"))
188        OutputFilename = IFN.drop_back(4);
189      else
190        OutputFilename = IFN;
191
192      switch (FileType) {
193      case TargetMachine::CGFT_AssemblyFile:
194        if (TargetName[0] == 'c') {
195          if (TargetName[1] == 0)
196            OutputFilename += ".cbe.c";
197          else if (TargetName[1] == 'p' && TargetName[2] == 'p')
198            OutputFilename += ".cpp";
199          else
200            OutputFilename += ".s";
201        } else
202          OutputFilename += ".s";
203        break;
204      case TargetMachine::CGFT_ObjectFile:
205        if (OS == Triple::Win32)
206          OutputFilename += ".obj";
207        else
208          OutputFilename += ".o";
209        break;
210      case TargetMachine::CGFT_Null:
211        OutputFilename += ".null";
212        break;
213      }
214    }
215  }
216
217  // Decide if we need "binary" output.
218  bool Binary = false;
219  switch (FileType) {
220  case TargetMachine::CGFT_AssemblyFile:
221    break;
222  case TargetMachine::CGFT_ObjectFile:
223  case TargetMachine::CGFT_Null:
224    Binary = true;
225    break;
226  }
227
228  // Open the file.
229  std::error_code EC;
230  sys::fs::OpenFlags OpenFlags = sys::fs::F_None;
231  if (!Binary)
232    OpenFlags |= sys::fs::F_Text;
233  auto FDOut = llvm::make_unique<ToolOutputFile>(OutputFilename, EC, OpenFlags);
234  if (EC) {
235    WithColor::error() << EC.message() << '\n';
236    return nullptr;
237  }
238
239  return FDOut;
240}
241
242struct LLCDiagnosticHandler : public DiagnosticHandler {
243  bool *HasError;
244  LLCDiagnosticHandler(bool *HasErrorPtr) : HasError(HasErrorPtr) {}
245  bool handleDiagnostics(const DiagnosticInfo &DI) override {
246    if (DI.getSeverity() == DS_Error)
247      *HasError = true;
248
249    if (auto *Remark = dyn_cast<DiagnosticInfoOptimizationBase>(&DI))
250      if (!Remark->isEnabled())
251        return true;
252
253    DiagnosticPrinterRawOStream DP(errs());
254    errs() << LLVMContext::getDiagnosticMessagePrefix(DI.getSeverity()) << ": ";
255    DI.print(DP);
256    errs() << "\n";
257    return true;
258  }
259};
260
261static void InlineAsmDiagHandler(const SMDiagnostic &SMD, void *Context,
262                                 unsigned LocCookie) {
263  bool *HasError = static_cast<bool *>(Context);
264  if (SMD.getKind() == SourceMgr::DK_Error)
265    *HasError = true;
266
267  SMD.print(nullptr, errs());
268
269  // For testing purposes, we print the LocCookie here.
270  if (LocCookie)
271    WithColor::note() << "!srcloc = " << LocCookie << "\n";
272}
273
274// main - Entry point for the llc compiler.
275//
276int main(int argc, char **argv) {
277  InitLLVM X(argc, argv);
278
279  // Enable debug stream buffering.
280  EnableDebugBuffering = true;
281
282  LLVMContext Context;
283
284  // Initialize targets first, so that --version shows registered targets.
285  InitializeAllTargets();
286  InitializeAllTargetMCs();
287  InitializeAllAsmPrinters();
288  InitializeAllAsmParsers();
289
290  // Initialize codegen and IR passes used by llc so that the -print-after,
291  // -print-before, and -stop-after options work.
292  PassRegistry *Registry = PassRegistry::getPassRegistry();
293  initializeCore(*Registry);
294  initializeCodeGen(*Registry);
295  initializeLoopStrengthReducePass(*Registry);
296  initializeLowerIntrinsicsPass(*Registry);
297  initializeEntryExitInstrumenterPass(*Registry);
298  initializePostInlineEntryExitInstrumenterPass(*Registry);
299  initializeUnreachableBlockElimLegacyPassPass(*Registry);
300  initializeConstantHoistingLegacyPassPass(*Registry);
301  initializeScalarOpts(*Registry);
302  initializeVectorization(*Registry);
303  initializeScalarizeMaskedMemIntrinPass(*Registry);
304  initializeExpandReductionsPass(*Registry);
305
306  // Initialize debugging passes.
307  initializeScavengerTestPass(*Registry);
308
309  // Register the target printer for --version.
310  cl::AddExtraVersionPrinter(TargetRegistry::printRegisteredTargetsForVersion);
311
312  cl::ParseCommandLineOptions(argc, argv, "llvm system compiler\n");
313
314  Context.setDiscardValueNames(DiscardValueNames);
315
316  // Set a diagnostic handler that doesn't exit on the first error
317  bool HasError = false;
318  Context.setDiagnosticHandler(
319      llvm::make_unique<LLCDiagnosticHandler>(&HasError));
320  Context.setInlineAsmDiagnosticHandler(InlineAsmDiagHandler, &HasError);
321
322  if (PassRemarksWithHotness)
323    Context.setDiagnosticsHotnessRequested(true);
324
325  if (PassRemarksHotnessThreshold)
326    Context.setDiagnosticsHotnessThreshold(PassRemarksHotnessThreshold);
327
328  std::unique_ptr<ToolOutputFile> YamlFile;
329  if (RemarksFilename != "") {
330    std::error_code EC;
331    YamlFile =
332        llvm::make_unique<ToolOutputFile>(RemarksFilename, EC, sys::fs::F_None);
333    if (EC) {
334      WithColor::error(errs(), argv[0]) << EC.message() << '\n';
335      return 1;
336    }
337    Context.setDiagnosticsOutputFile(
338        llvm::make_unique<yaml::Output>(YamlFile->os()));
339  }
340
341  if (InputLanguage != "" && InputLanguage != "ir" &&
342      InputLanguage != "mir") {
343    WithColor::error(errs(), argv[0])
344        << "input language must be '', 'IR' or 'MIR'\n";
345    return 1;
346  }
347
348  // Compile the module TimeCompilations times to give better compile time
349  // metrics.
350  for (unsigned I = TimeCompilations; I; --I)
351    if (int RetVal = compileModule(argv, Context))
352      return RetVal;
353
354  if (YamlFile)
355    YamlFile->keep();
356  return 0;
357}
358
359static bool addPass(PassManagerBase &PM, const char *argv0,
360                    StringRef PassName, TargetPassConfig &TPC) {
361  if (PassName == "none")
362    return false;
363
364  const PassRegistry *PR = PassRegistry::getPassRegistry();
365  const PassInfo *PI = PR->getPassInfo(PassName);
366  if (!PI) {
367    WithColor::error(errs(), argv0)
368        << "run-pass " << PassName << " is not registered.\n";
369    return true;
370  }
371
372  Pass *P;
373  if (PI->getNormalCtor())
374    P = PI->getNormalCtor()();
375  else {
376    WithColor::error(errs(), argv0)
377        << "cannot create pass: " << PI->getPassName() << "\n";
378    return true;
379  }
380  std::string Banner = std::string("After ") + std::string(P->getPassName());
381  PM.add(P);
382  TPC.printAndVerify(Banner);
383
384  return false;
385}
386
387static int compileModule(char **argv, LLVMContext &Context) {
388  // Load the module to be compiled...
389  SMDiagnostic Err;
390  std::unique_ptr<Module> M;
391  std::unique_ptr<MIRParser> MIR;
392  Triple TheTriple;
393
394  bool SkipModule = MCPU == "help" ||
395                    (!MAttrs.empty() && MAttrs.front() == "help");
396
397  // If user just wants to list available options, skip module loading
398  if (!SkipModule) {
399    if (InputLanguage == "mir" ||
400        (InputLanguage == "" && StringRef(InputFilename).endswith(".mir"))) {
401      MIR = createMIRParserFromFile(InputFilename, Err, Context);
402      if (MIR)
403        M = MIR->parseIRModule();
404    } else
405      M = parseIRFile(InputFilename, Err, Context, false);
406    if (!M) {
407      Err.print(argv[0], WithColor::error(errs(), argv[0]));
408      return 1;
409    }
410
411    // If we are supposed to override the target triple, do so now.
412    if (!TargetTriple.empty())
413      M->setTargetTriple(Triple::normalize(TargetTriple));
414    TheTriple = Triple(M->getTargetTriple());
415  } else {
416    TheTriple = Triple(Triple::normalize(TargetTriple));
417  }
418
419  if (TheTriple.getTriple().empty())
420    TheTriple.setTriple(sys::getDefaultTargetTriple());
421
422  // Get the target specific parser.
423  std::string Error;
424  const Target *TheTarget = TargetRegistry::lookupTarget(MArch, TheTriple,
425                                                         Error);
426  if (!TheTarget) {
427    WithColor::error(errs(), argv[0]) << Error;
428    return 1;
429  }
430
431  std::string CPUStr = getCPUStr(), FeaturesStr = getFeaturesStr();
432
433  CodeGenOpt::Level OLvl = CodeGenOpt::Default;
434  switch (OptLevel) {
435  default:
436    WithColor::error(errs(), argv[0]) << "invalid optimization level.\n";
437    return 1;
438  case ' ': break;
439  case '0': OLvl = CodeGenOpt::None; break;
440  case '1': OLvl = CodeGenOpt::Less; break;
441  case '2': OLvl = CodeGenOpt::Default; break;
442  case '3': OLvl = CodeGenOpt::Aggressive; break;
443  }
444
445  TargetOptions Options = InitTargetOptionsFromCodeGenFlags();
446  Options.DisableIntegratedAS = NoIntegratedAssembler;
447  Options.MCOptions.ShowMCEncoding = ShowMCEncoding;
448  Options.MCOptions.MCUseDwarfDirectory = EnableDwarfDirectory;
449  Options.MCOptions.AsmVerbose = AsmVerbose;
450  Options.MCOptions.PreserveAsmComments = PreserveComments;
451  Options.MCOptions.IASSearchPaths = IncludeDirs;
452  Options.MCOptions.SplitDwarfFile = SplitDwarfFile;
453
454  std::unique_ptr<TargetMachine> Target(TheTarget->createTargetMachine(
455      TheTriple.getTriple(), CPUStr, FeaturesStr, Options, getRelocModel(),
456      getCodeModel(), OLvl));
457
458  assert(Target && "Could not allocate target machine!");
459
460  // If we don't have a module then just exit now. We do this down
461  // here since the CPU/Feature help is underneath the target machine
462  // creation.
463  if (SkipModule)
464    return 0;
465
466  assert(M && "Should have exited if we didn't have a module!");
467  if (FloatABIForCalls != FloatABI::Default)
468    Options.FloatABIType = FloatABIForCalls;
469
470  // Figure out where we are going to send the output.
471  std::unique_ptr<ToolOutputFile> Out =
472      GetOutputStream(TheTarget->getName(), TheTriple.getOS(), argv[0]);
473  if (!Out) return 1;
474
475  std::unique_ptr<ToolOutputFile> DwoOut;
476  if (!SplitDwarfOutputFile.empty()) {
477    std::error_code EC;
478    DwoOut = llvm::make_unique<ToolOutputFile>(SplitDwarfOutputFile, EC,
479                                               sys::fs::F_None);
480    if (EC) {
481      WithColor::error(errs(), argv[0]) << EC.message() << '\n';
482      return 1;
483    }
484  }
485
486  // Build up all of the passes that we want to do to the module.
487  legacy::PassManager PM;
488
489  // Add an appropriate TargetLibraryInfo pass for the module's triple.
490  TargetLibraryInfoImpl TLII(Triple(M->getTargetTriple()));
491
492  // The -disable-simplify-libcalls flag actually disables all builtin optzns.
493  if (DisableSimplifyLibCalls)
494    TLII.disableAllFunctions();
495  PM.add(new TargetLibraryInfoWrapperPass(TLII));
496
497  // Add the target data from the target machine, if it exists, or the module.
498  M->setDataLayout(Target->createDataLayout());
499
500  // This needs to be done after setting datalayout since it calls verifier
501  // to check debug info whereas verifier relies on correct datalayout.
502  UpgradeDebugInfo(*M);
503
504  // Verify module immediately to catch problems before doInitialization() is
505  // called on any passes.
506  if (!NoVerify && verifyModule(*M, &errs())) {
507    std::string Prefix =
508        (Twine(argv[0]) + Twine(": ") + Twine(InputFilename)).str();
509    WithColor::error(errs(), Prefix) << "input module is broken!\n";
510    return 1;
511  }
512
513  // Override function attributes based on CPUStr, FeaturesStr, and command line
514  // flags.
515  setFunctionAttributes(CPUStr, FeaturesStr, *M);
516
517  if (RelaxAll.getNumOccurrences() > 0 &&
518      FileType != TargetMachine::CGFT_ObjectFile)
519    WithColor::warning(errs(), argv[0])
520        << ": warning: ignoring -mc-relax-all because filetype != obj";
521
522  {
523    raw_pwrite_stream *OS = &Out->os();
524
525    // Manually do the buffering rather than using buffer_ostream,
526    // so we can memcmp the contents in CompileTwice mode
527    SmallVector<char, 0> Buffer;
528    std::unique_ptr<raw_svector_ostream> BOS;
529    if ((FileType != TargetMachine::CGFT_AssemblyFile &&
530         !Out->os().supportsSeeking()) ||
531        CompileTwice) {
532      BOS = make_unique<raw_svector_ostream>(Buffer);
533      OS = BOS.get();
534    }
535
536    const char *argv0 = argv[0];
537    LLVMTargetMachine &LLVMTM = static_cast<LLVMTargetMachine&>(*Target);
538    MachineModuleInfo *MMI = new MachineModuleInfo(&LLVMTM);
539
540    // Construct a custom pass pipeline that starts after instruction
541    // selection.
542    if (!RunPassNames->empty()) {
543      if (!MIR) {
544        WithColor::warning(errs(), argv[0])
545            << "run-pass is for .mir file only.\n";
546        return 1;
547      }
548      TargetPassConfig &TPC = *LLVMTM.createPassConfig(PM);
549      if (TPC.hasLimitedCodeGenPipeline()) {
550        WithColor::warning(errs(), argv[0])
551            << "run-pass cannot be used with "
552            << TPC.getLimitedCodeGenPipelineReason(" and ") << ".\n";
553        return 1;
554      }
555
556      TPC.setDisableVerify(NoVerify);
557      PM.add(&TPC);
558      PM.add(MMI);
559      TPC.printAndVerify("");
560      for (const std::string &RunPassName : *RunPassNames) {
561        if (addPass(PM, argv0, RunPassName, TPC))
562          return 1;
563      }
564      TPC.setInitialized();
565      PM.add(createPrintMIRPass(*OS));
566      PM.add(createFreeMachineFunctionPass());
567    } else if (Target->addPassesToEmitFile(PM, *OS,
568                                           DwoOut ? &DwoOut->os() : nullptr,
569                                           FileType, NoVerify, MMI)) {
570      WithColor::warning(errs(), argv[0])
571          << "target does not support generation of this"
572          << " file type!\n";
573      return 1;
574    }
575
576    if (MIR) {
577      assert(MMI && "Forgot to create MMI?");
578      if (MIR->parseMachineFunctions(*M, *MMI))
579        return 1;
580    }
581
582    // Before executing passes, print the final values of the LLVM options.
583    cl::PrintOptionValues();
584
585    // If requested, run the pass manager over the same module again,
586    // to catch any bugs due to persistent state in the passes. Note that
587    // opt has the same functionality, so it may be worth abstracting this out
588    // in the future.
589    SmallVector<char, 0> CompileTwiceBuffer;
590    if (CompileTwice) {
591      std::unique_ptr<Module> M2(llvm::CloneModule(*M));
592      PM.run(*M2);
593      CompileTwiceBuffer = Buffer;
594      Buffer.clear();
595    }
596
597    PM.run(*M);
598
599    auto HasError =
600        ((const LLCDiagnosticHandler *)(Context.getDiagHandlerPtr()))->HasError;
601    if (*HasError)
602      return 1;
603
604    // Compare the two outputs and make sure they're the same
605    if (CompileTwice) {
606      if (Buffer.size() != CompileTwiceBuffer.size() ||
607          (memcmp(Buffer.data(), CompileTwiceBuffer.data(), Buffer.size()) !=
608           0)) {
609        errs()
610            << "Running the pass manager twice changed the output.\n"
611               "Writing the result of the second run to the specified output\n"
612               "To generate the one-run comparison binary, just run without\n"
613               "the compile-twice option\n";
614        Out->os() << Buffer;
615        Out->keep();
616        return 1;
617      }
618    }
619
620    if (BOS) {
621      Out->os() << Buffer;
622    }
623  }
624
625  // Declare success.
626  Out->keep();
627  if (DwoOut)
628    DwoOut->keep();
629
630  return 0;
631}
632