1 //===-- llc.cpp - Implement the LLVM Native Code Generator ----------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This is the llc code generator driver. It provides a convenient
10 // command-line interface for generating native assembly-language code
11 // or C code, given LLVM bitcode.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #include "llvm/ADT/STLExtras.h"
16 #include "llvm/ADT/ScopeExit.h"
17 #include "llvm/Analysis/TargetLibraryInfo.h"
18 #include "llvm/CodeGen/CommandFlags.h"
19 #include "llvm/CodeGen/LinkAllAsmWriterComponents.h"
20 #include "llvm/CodeGen/LinkAllCodegenComponents.h"
21 #include "llvm/CodeGen/MIRParser/MIRParser.h"
22 #include "llvm/CodeGen/MachineFunctionPass.h"
23 #include "llvm/CodeGen/MachineModuleInfo.h"
24 #include "llvm/CodeGen/TargetPassConfig.h"
25 #include "llvm/CodeGen/TargetSubtargetInfo.h"
26 #include "llvm/IR/AutoUpgrade.h"
27 #include "llvm/IR/DataLayout.h"
28 #include "llvm/IR/DiagnosticInfo.h"
29 #include "llvm/IR/DiagnosticPrinter.h"
30 #include "llvm/IR/LLVMContext.h"
31 #include "llvm/IR/LLVMRemarkStreamer.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/InitializePasses.h"
37 #include "llvm/MC/MCTargetOptionsCommandFlags.h"
38 #include "llvm/MC/TargetRegistry.h"
39 #include "llvm/Pass.h"
40 #include "llvm/Remarks/HotnessThresholdParser.h"
41 #include "llvm/Support/CommandLine.h"
42 #include "llvm/Support/Debug.h"
43 #include "llvm/Support/FileSystem.h"
44 #include "llvm/Support/FormattedStream.h"
45 #include "llvm/Support/InitLLVM.h"
46 #include "llvm/Support/PluginLoader.h"
47 #include "llvm/Support/SourceMgr.h"
48 #include "llvm/Support/TargetSelect.h"
49 #include "llvm/Support/TimeProfiler.h"
50 #include "llvm/Support/ToolOutputFile.h"
51 #include "llvm/Support/WithColor.h"
52 #include "llvm/Target/TargetLoweringObjectFile.h"
53 #include "llvm/Target/TargetMachine.h"
54 #include "llvm/TargetParser/Host.h"
55 #include "llvm/TargetParser/SubtargetFeature.h"
56 #include "llvm/TargetParser/Triple.h"
57 #include "llvm/Transforms/Utils/Cloning.h"
58 #include <memory>
59 #include <optional>
60 using namespace llvm;
61 
62 static codegen::RegisterCodeGenFlags CGF;
63 
64 // General options for llc.  Other pass-specific options are specified
65 // within the corresponding llc passes, and target-specific options
66 // and back-end code generation options are specified with the target machine.
67 //
68 static cl::opt<std::string>
69 InputFilename(cl::Positional, cl::desc("<input bitcode>"), cl::init("-"));
70 
71 static cl::opt<std::string>
72 InputLanguage("x", cl::desc("Input language ('ir' or 'mir')"));
73 
74 static cl::opt<std::string>
75 OutputFilename("o", cl::desc("Output filename"), cl::value_desc("filename"));
76 
77 static cl::opt<std::string>
78     SplitDwarfOutputFile("split-dwarf-output",
79                          cl::desc(".dwo output filename"),
80                          cl::value_desc("filename"));
81 
82 static cl::opt<unsigned>
83 TimeCompilations("time-compilations", cl::Hidden, cl::init(1u),
84                  cl::value_desc("N"),
85                  cl::desc("Repeat compilation N times for timing"));
86 
87 static cl::opt<bool> TimeTrace("time-trace", cl::desc("Record time trace"));
88 
89 static cl::opt<unsigned> TimeTraceGranularity(
90     "time-trace-granularity",
91     cl::desc(
92         "Minimum time granularity (in microseconds) traced by time profiler"),
93     cl::init(500), cl::Hidden);
94 
95 static cl::opt<std::string>
96     TimeTraceFile("time-trace-file",
97                   cl::desc("Specify time trace file destination"),
98                   cl::value_desc("filename"));
99 
100 static cl::opt<std::string>
101     BinutilsVersion("binutils-version", cl::Hidden,
102                     cl::desc("Produced object files can use all ELF features "
103                              "supported by this binutils version and newer."
104                              "If -no-integrated-as is specified, the generated "
105                              "assembly will consider GNU as support."
106                              "'none' means that all ELF features can be used, "
107                              "regardless of binutils support"));
108 
109 static cl::opt<bool>
110     PreserveComments("preserve-as-comments", cl::Hidden,
111                      cl::desc("Preserve Comments in outputted assembly"),
112                      cl::init(true));
113 
114 // Determine optimization level.
115 static cl::opt<char>
116     OptLevel("O",
117              cl::desc("Optimization level. [-O0, -O1, -O2, or -O3] "
118                       "(default = '-O2')"),
119              cl::Prefix, cl::init('2'));
120 
121 static cl::opt<std::string>
122 TargetTriple("mtriple", cl::desc("Override target triple for module"));
123 
124 static cl::opt<std::string> SplitDwarfFile(
125     "split-dwarf-file",
126     cl::desc(
127         "Specify the name of the .dwo file to encode in the DWARF output"));
128 
129 static cl::opt<bool> NoVerify("disable-verify", cl::Hidden,
130                               cl::desc("Do not verify input module"));
131 
132 static cl::opt<bool> DisableSimplifyLibCalls("disable-simplify-libcalls",
133                                              cl::desc("Disable simplify-libcalls"));
134 
135 static cl::opt<bool> ShowMCEncoding("show-mc-encoding", cl::Hidden,
136                                     cl::desc("Show encoding in .s output"));
137 
138 static cl::opt<bool>
139     DwarfDirectory("dwarf-directory", cl::Hidden,
140                    cl::desc("Use .file directives with an explicit directory"),
141                    cl::init(true));
142 
143 static cl::opt<bool> AsmVerbose("asm-verbose",
144                                 cl::desc("Add comments to directives."),
145                                 cl::init(true));
146 
147 static cl::opt<bool>
148     CompileTwice("compile-twice", cl::Hidden,
149                  cl::desc("Run everything twice, re-using the same pass "
150                           "manager and verify the result is the same."),
151                  cl::init(false));
152 
153 static cl::opt<bool> DiscardValueNames(
154     "discard-value-names",
155     cl::desc("Discard names from Value (other than GlobalValue)."),
156     cl::init(false), cl::Hidden);
157 
158 static cl::list<std::string> IncludeDirs("I", cl::desc("include search path"));
159 
160 static cl::opt<bool> RemarksWithHotness(
161     "pass-remarks-with-hotness",
162     cl::desc("With PGO, include profile count in optimization remarks"),
163     cl::Hidden);
164 
165 static cl::opt<std::optional<uint64_t>, false, remarks::HotnessThresholdParser>
166     RemarksHotnessThreshold(
167         "pass-remarks-hotness-threshold",
168         cl::desc("Minimum profile count required for "
169                  "an optimization remark to be output. "
170                  "Use 'auto' to apply the threshold from profile summary."),
171         cl::value_desc("N or 'auto'"), cl::init(0), cl::Hidden);
172 
173 static cl::opt<std::string>
174     RemarksFilename("pass-remarks-output",
175                     cl::desc("Output filename for pass remarks"),
176                     cl::value_desc("filename"));
177 
178 static cl::opt<std::string>
179     RemarksPasses("pass-remarks-filter",
180                   cl::desc("Only record optimization remarks from passes whose "
181                            "names match the given regular expression"),
182                   cl::value_desc("regex"));
183 
184 static cl::opt<std::string> RemarksFormat(
185     "pass-remarks-format",
186     cl::desc("The format used for serializing remarks (default: YAML)"),
187     cl::value_desc("format"), cl::init("yaml"));
188 
189 namespace {
190 
191 std::vector<std::string> &getRunPassNames() {
192   static std::vector<std::string> RunPassNames;
193   return RunPassNames;
194 }
195 
196 struct RunPassOption {
197   void operator=(const std::string &Val) const {
198     if (Val.empty())
199       return;
200     SmallVector<StringRef, 8> PassNames;
201     StringRef(Val).split(PassNames, ',', -1, false);
202     for (auto PassName : PassNames)
203       getRunPassNames().push_back(std::string(PassName));
204   }
205 };
206 }
207 
208 static RunPassOption RunPassOpt;
209 
210 static cl::opt<RunPassOption, true, cl::parser<std::string>> RunPass(
211     "run-pass",
212     cl::desc("Run compiler only for specified passes (comma separated list)"),
213     cl::value_desc("pass-name"), cl::location(RunPassOpt));
214 
215 static int compileModule(char **, LLVMContext &);
216 
217 [[noreturn]] static void reportError(Twine Msg, StringRef Filename = "") {
218   SmallString<256> Prefix;
219   if (!Filename.empty()) {
220     if (Filename == "-")
221       Filename = "<stdin>";
222     ("'" + Twine(Filename) + "': ").toStringRef(Prefix);
223   }
224   WithColor::error(errs(), "llc") << Prefix << Msg << "\n";
225   exit(1);
226 }
227 
228 [[noreturn]] static void reportError(Error Err, StringRef Filename) {
229   assert(Err);
230   handleAllErrors(createFileError(Filename, std::move(Err)),
231                   [&](const ErrorInfoBase &EI) { reportError(EI.message()); });
232   llvm_unreachable("reportError() should not return");
233 }
234 
235 static std::unique_ptr<ToolOutputFile> GetOutputStream(const char *TargetName,
236                                                        Triple::OSType OS,
237                                                        const char *ProgName) {
238   // If we don't yet have an output filename, make one.
239   if (OutputFilename.empty()) {
240     if (InputFilename == "-")
241       OutputFilename = "-";
242     else {
243       // If InputFilename ends in .bc or .ll, remove it.
244       StringRef IFN = InputFilename;
245       if (IFN.endswith(".bc") || IFN.endswith(".ll"))
246         OutputFilename = std::string(IFN.drop_back(3));
247       else if (IFN.endswith(".mir"))
248         OutputFilename = std::string(IFN.drop_back(4));
249       else
250         OutputFilename = std::string(IFN);
251 
252       switch (codegen::getFileType()) {
253       case CGFT_AssemblyFile:
254         if (TargetName[0] == 'c') {
255           if (TargetName[1] == 0)
256             OutputFilename += ".cbe.c";
257           else if (TargetName[1] == 'p' && TargetName[2] == 'p')
258             OutputFilename += ".cpp";
259           else
260             OutputFilename += ".s";
261         } else
262           OutputFilename += ".s";
263         break;
264       case CGFT_ObjectFile:
265         if (OS == Triple::Win32)
266           OutputFilename += ".obj";
267         else
268           OutputFilename += ".o";
269         break;
270       case CGFT_Null:
271         OutputFilename = "-";
272         break;
273       }
274     }
275   }
276 
277   // Decide if we need "binary" output.
278   bool Binary = false;
279   switch (codegen::getFileType()) {
280   case CGFT_AssemblyFile:
281     break;
282   case CGFT_ObjectFile:
283   case CGFT_Null:
284     Binary = true;
285     break;
286   }
287 
288   // Open the file.
289   std::error_code EC;
290   sys::fs::OpenFlags OpenFlags = sys::fs::OF_None;
291   if (!Binary)
292     OpenFlags |= sys::fs::OF_TextWithCRLF;
293   auto FDOut = std::make_unique<ToolOutputFile>(OutputFilename, EC, OpenFlags);
294   if (EC) {
295     reportError(EC.message());
296     return nullptr;
297   }
298 
299   return FDOut;
300 }
301 
302 struct LLCDiagnosticHandler : public DiagnosticHandler {
303   bool *HasError;
304   LLCDiagnosticHandler(bool *HasErrorPtr) : HasError(HasErrorPtr) {}
305   bool handleDiagnostics(const DiagnosticInfo &DI) override {
306     if (DI.getKind() == llvm::DK_SrcMgr) {
307       const auto &DISM = cast<DiagnosticInfoSrcMgr>(DI);
308       const SMDiagnostic &SMD = DISM.getSMDiag();
309 
310       if (SMD.getKind() == SourceMgr::DK_Error)
311         *HasError = true;
312 
313       SMD.print(nullptr, errs());
314 
315       // For testing purposes, we print the LocCookie here.
316       if (DISM.isInlineAsmDiag() && DISM.getLocCookie())
317         WithColor::note() << "!srcloc = " << DISM.getLocCookie() << "\n";
318 
319       return true;
320     }
321 
322     if (DI.getSeverity() == DS_Error)
323       *HasError = true;
324 
325     if (auto *Remark = dyn_cast<DiagnosticInfoOptimizationBase>(&DI))
326       if (!Remark->isEnabled())
327         return true;
328 
329     DiagnosticPrinterRawOStream DP(errs());
330     errs() << LLVMContext::getDiagnosticMessagePrefix(DI.getSeverity()) << ": ";
331     DI.print(DP);
332     errs() << "\n";
333     return true;
334   }
335 };
336 
337 // main - Entry point for the llc compiler.
338 //
339 int main(int argc, char **argv) {
340   InitLLVM X(argc, argv);
341 
342   // Enable debug stream buffering.
343   EnableDebugBuffering = true;
344 
345   // Initialize targets first, so that --version shows registered targets.
346   InitializeAllTargets();
347   InitializeAllTargetMCs();
348   InitializeAllAsmPrinters();
349   InitializeAllAsmParsers();
350 
351   // Initialize codegen and IR passes used by llc so that the -print-after,
352   // -print-before, and -stop-after options work.
353   PassRegistry *Registry = PassRegistry::getPassRegistry();
354   initializeCore(*Registry);
355   initializeCodeGen(*Registry);
356   initializeLoopStrengthReducePass(*Registry);
357   initializeLowerIntrinsicsPass(*Registry);
358   initializeUnreachableBlockElimLegacyPassPass(*Registry);
359   initializeConstantHoistingLegacyPassPass(*Registry);
360   initializeScalarOpts(*Registry);
361   initializeVectorization(*Registry);
362   initializeScalarizeMaskedMemIntrinLegacyPassPass(*Registry);
363   initializeExpandReductionsPass(*Registry);
364   initializeExpandVectorPredicationPass(*Registry);
365   initializeHardwareLoopsLegacyPass(*Registry);
366   initializeTransformUtils(*Registry);
367   initializeReplaceWithVeclibLegacyPass(*Registry);
368   initializeTLSVariableHoistLegacyPassPass(*Registry);
369 
370   // Initialize debugging passes.
371   initializeScavengerTestPass(*Registry);
372 
373   // Register the Target and CPU printer for --version.
374   cl::AddExtraVersionPrinter(sys::printDefaultTargetAndDetectedCPU);
375   // Register the target printer for --version.
376   cl::AddExtraVersionPrinter(TargetRegistry::printRegisteredTargetsForVersion);
377 
378   cl::ParseCommandLineOptions(argc, argv, "llvm system compiler\n");
379 
380   if (TimeTrace)
381     timeTraceProfilerInitialize(TimeTraceGranularity, argv[0]);
382   auto TimeTraceScopeExit = make_scope_exit([]() {
383     if (TimeTrace) {
384       if (auto E = timeTraceProfilerWrite(TimeTraceFile, OutputFilename)) {
385         handleAllErrors(std::move(E), [&](const StringError &SE) {
386           errs() << SE.getMessage() << "\n";
387         });
388         return;
389       }
390       timeTraceProfilerCleanup();
391     }
392   });
393 
394   LLVMContext Context;
395   Context.setDiscardValueNames(DiscardValueNames);
396 
397   // Set a diagnostic handler that doesn't exit on the first error
398   bool HasError = false;
399   Context.setDiagnosticHandler(
400       std::make_unique<LLCDiagnosticHandler>(&HasError));
401 
402   Expected<std::unique_ptr<ToolOutputFile>> RemarksFileOrErr =
403       setupLLVMOptimizationRemarks(Context, RemarksFilename, RemarksPasses,
404                                    RemarksFormat, RemarksWithHotness,
405                                    RemarksHotnessThreshold);
406   if (Error E = RemarksFileOrErr.takeError())
407     reportError(std::move(E), RemarksFilename);
408   std::unique_ptr<ToolOutputFile> RemarksFile = std::move(*RemarksFileOrErr);
409 
410   if (InputLanguage != "" && InputLanguage != "ir" && InputLanguage != "mir")
411     reportError("input language must be '', 'IR' or 'MIR'");
412 
413   // Compile the module TimeCompilations times to give better compile time
414   // metrics.
415   for (unsigned I = TimeCompilations; I; --I)
416     if (int RetVal = compileModule(argv, Context))
417       return RetVal;
418 
419   if (RemarksFile)
420     RemarksFile->keep();
421   return 0;
422 }
423 
424 static bool addPass(PassManagerBase &PM, const char *argv0,
425                     StringRef PassName, TargetPassConfig &TPC) {
426   if (PassName == "none")
427     return false;
428 
429   const PassRegistry *PR = PassRegistry::getPassRegistry();
430   const PassInfo *PI = PR->getPassInfo(PassName);
431   if (!PI) {
432     WithColor::error(errs(), argv0)
433         << "run-pass " << PassName << " is not registered.\n";
434     return true;
435   }
436 
437   Pass *P;
438   if (PI->getNormalCtor())
439     P = PI->getNormalCtor()();
440   else {
441     WithColor::error(errs(), argv0)
442         << "cannot create pass: " << PI->getPassName() << "\n";
443     return true;
444   }
445   std::string Banner = std::string("After ") + std::string(P->getPassName());
446   TPC.addMachinePrePasses();
447   PM.add(P);
448   TPC.addMachinePostPasses(Banner);
449 
450   return false;
451 }
452 
453 static int compileModule(char **argv, LLVMContext &Context) {
454   // Load the module to be compiled...
455   SMDiagnostic Err;
456   std::unique_ptr<Module> M;
457   std::unique_ptr<MIRParser> MIR;
458   Triple TheTriple;
459   std::string CPUStr = codegen::getCPUStr(),
460               FeaturesStr = codegen::getFeaturesStr();
461 
462   // Set attributes on functions as loaded from MIR from command line arguments.
463   auto setMIRFunctionAttributes = [&CPUStr, &FeaturesStr](Function &F) {
464     codegen::setFunctionAttributes(CPUStr, FeaturesStr, F);
465   };
466 
467   auto MAttrs = codegen::getMAttrs();
468   bool SkipModule =
469       CPUStr == "help" || (!MAttrs.empty() && MAttrs.front() == "help");
470 
471   CodeGenOpt::Level OLvl;
472   if (auto Level = CodeGenOpt::parseLevel(OptLevel)) {
473     OLvl = *Level;
474   } else {
475     WithColor::error(errs(), argv[0]) << "invalid optimization level.\n";
476     return 1;
477   }
478 
479   // Parse 'none' or '$major.$minor'. Disallow -binutils-version=0 because we
480   // use that to indicate the MC default.
481   if (!BinutilsVersion.empty() && BinutilsVersion != "none") {
482     StringRef V = BinutilsVersion.getValue();
483     unsigned Num;
484     if (V.consumeInteger(10, Num) || Num == 0 ||
485         !(V.empty() ||
486           (V.consume_front(".") && !V.consumeInteger(10, Num) && V.empty()))) {
487       WithColor::error(errs(), argv[0])
488           << "invalid -binutils-version, accepting 'none' or major.minor\n";
489       return 1;
490     }
491   }
492   TargetOptions Options;
493   auto InitializeOptions = [&](const Triple &TheTriple) {
494     Options = codegen::InitTargetOptionsFromCodeGenFlags(TheTriple);
495 
496     if (Options.XCOFFReadOnlyPointers) {
497       if (!TheTriple.isOSAIX())
498         reportError("-mxcoff-roptr option is only supported on AIX",
499                     InputFilename);
500 
501       // Since the storage mapping class is specified per csect,
502       // without using data sections, it is less effective to use read-only
503       // pointers. Using read-only pointers may cause other RO variables in the
504       // same csect to become RW when the linker acts upon `-bforceimprw`;
505       // therefore, we require that separate data sections are used in the
506       // presence of ReadOnlyPointers. We respect the setting of data-sections
507       // since we have not found reasons to do otherwise that overcome the user
508       // surprise of not respecting the setting.
509       if (!Options.DataSections)
510         reportError("-mxcoff-roptr option must be used with -data-sections",
511                     InputFilename);
512     }
513 
514     Options.BinutilsVersion =
515         TargetMachine::parseBinutilsVersion(BinutilsVersion);
516     Options.MCOptions.ShowMCEncoding = ShowMCEncoding;
517     Options.MCOptions.AsmVerbose = AsmVerbose;
518     Options.MCOptions.PreserveAsmComments = PreserveComments;
519     Options.MCOptions.IASSearchPaths = IncludeDirs;
520     Options.MCOptions.SplitDwarfFile = SplitDwarfFile;
521     if (DwarfDirectory.getPosition()) {
522       Options.MCOptions.MCUseDwarfDirectory =
523           DwarfDirectory ? MCTargetOptions::EnableDwarfDirectory
524                          : MCTargetOptions::DisableDwarfDirectory;
525     } else {
526       // -dwarf-directory is not set explicitly. Some assemblers
527       // (e.g. GNU as or ptxas) do not support `.file directory'
528       // syntax prior to DWARFv5. Let the target decide the default
529       // value.
530       Options.MCOptions.MCUseDwarfDirectory =
531           MCTargetOptions::DefaultDwarfDirectory;
532     }
533   };
534 
535   std::optional<Reloc::Model> RM = codegen::getExplicitRelocModel();
536   std::optional<CodeModel::Model> CM = codegen::getExplicitCodeModel();
537 
538   const Target *TheTarget = nullptr;
539   std::unique_ptr<TargetMachine> Target;
540 
541   // If user just wants to list available options, skip module loading
542   if (!SkipModule) {
543     auto SetDataLayout = [&](StringRef DataLayoutTargetTriple,
544                              StringRef OldDLStr) -> std::optional<std::string> {
545       // If we are supposed to override the target triple, do so now.
546       std::string IRTargetTriple = DataLayoutTargetTriple.str();
547       if (!TargetTriple.empty())
548         IRTargetTriple = Triple::normalize(TargetTriple);
549       TheTriple = Triple(IRTargetTriple);
550       if (TheTriple.getTriple().empty())
551         TheTriple.setTriple(sys::getDefaultTargetTriple());
552 
553       std::string Error;
554       TheTarget =
555           TargetRegistry::lookupTarget(codegen::getMArch(), TheTriple, Error);
556       if (!TheTarget) {
557         WithColor::error(errs(), argv[0]) << Error;
558         exit(1);
559       }
560 
561       // On AIX, setting the relocation model to anything other than PIC is
562       // considered a user error.
563       if (TheTriple.isOSAIX() && RM && *RM != Reloc::PIC_)
564         reportError("invalid relocation model, AIX only supports PIC",
565                     InputFilename);
566 
567       InitializeOptions(TheTriple);
568       Target = std::unique_ptr<TargetMachine>(TheTarget->createTargetMachine(
569           TheTriple.getTriple(), CPUStr, FeaturesStr, Options, RM, CM, OLvl));
570       assert(Target && "Could not allocate target machine!");
571 
572       return Target->createDataLayout().getStringRepresentation();
573     };
574     if (InputLanguage == "mir" ||
575         (InputLanguage == "" && StringRef(InputFilename).endswith(".mir"))) {
576       MIR = createMIRParserFromFile(InputFilename, Err, Context,
577                                     setMIRFunctionAttributes);
578       if (MIR)
579         M = MIR->parseIRModule(SetDataLayout);
580     } else {
581       M = parseIRFile(InputFilename, Err, Context,
582                       ParserCallbacks(SetDataLayout));
583     }
584     if (!M) {
585       Err.print(argv[0], WithColor::error(errs(), argv[0]));
586       return 1;
587     }
588     if (!TargetTriple.empty())
589       M->setTargetTriple(Triple::normalize(TargetTriple));
590 
591     std::optional<CodeModel::Model> CM_IR = M->getCodeModel();
592     if (!CM && CM_IR)
593       Target->setCodeModel(*CM_IR);
594   } else {
595     TheTriple = Triple(Triple::normalize(TargetTriple));
596     if (TheTriple.getTriple().empty())
597       TheTriple.setTriple(sys::getDefaultTargetTriple());
598 
599     // Get the target specific parser.
600     std::string Error;
601     TheTarget =
602         TargetRegistry::lookupTarget(codegen::getMArch(), TheTriple, Error);
603     if (!TheTarget) {
604       WithColor::error(errs(), argv[0]) << Error;
605       return 1;
606     }
607 
608     // On AIX, setting the relocation model to anything other than PIC is
609     // considered a user error.
610     if (TheTriple.isOSAIX() && RM && *RM != Reloc::PIC_) {
611       WithColor::error(errs(), argv[0])
612           << "invalid relocation model, AIX only supports PIC.\n";
613       return 1;
614     }
615 
616     InitializeOptions(TheTriple);
617     Target = std::unique_ptr<TargetMachine>(TheTarget->createTargetMachine(
618         TheTriple.getTriple(), CPUStr, FeaturesStr, Options, RM, CM, OLvl));
619     assert(Target && "Could not allocate target machine!");
620 
621     // If we don't have a module then just exit now. We do this down
622     // here since the CPU/Feature help is underneath the target machine
623     // creation.
624     return 0;
625   }
626 
627   assert(M && "Should have exited if we didn't have a module!");
628   if (codegen::getFloatABIForCalls() != FloatABI::Default)
629     Options.FloatABIType = codegen::getFloatABIForCalls();
630 
631   // Figure out where we are going to send the output.
632   std::unique_ptr<ToolOutputFile> Out =
633       GetOutputStream(TheTarget->getName(), TheTriple.getOS(), argv[0]);
634   if (!Out) return 1;
635 
636   // Ensure the filename is passed down to CodeViewDebug.
637   Target->Options.ObjectFilenameForDebug = Out->outputFilename();
638 
639   std::unique_ptr<ToolOutputFile> DwoOut;
640   if (!SplitDwarfOutputFile.empty()) {
641     std::error_code EC;
642     DwoOut = std::make_unique<ToolOutputFile>(SplitDwarfOutputFile, EC,
643                                                sys::fs::OF_None);
644     if (EC)
645       reportError(EC.message(), SplitDwarfOutputFile);
646   }
647 
648   // Build up all of the passes that we want to do to the module.
649   legacy::PassManager PM;
650 
651   // Add an appropriate TargetLibraryInfo pass for the module's triple.
652   TargetLibraryInfoImpl TLII(Triple(M->getTargetTriple()));
653 
654   // The -disable-simplify-libcalls flag actually disables all builtin optzns.
655   if (DisableSimplifyLibCalls)
656     TLII.disableAllFunctions();
657   PM.add(new TargetLibraryInfoWrapperPass(TLII));
658 
659   // Verify module immediately to catch problems before doInitialization() is
660   // called on any passes.
661   if (!NoVerify && verifyModule(*M, &errs()))
662     reportError("input module cannot be verified", InputFilename);
663 
664   // Override function attributes based on CPUStr, FeaturesStr, and command line
665   // flags.
666   codegen::setFunctionAttributes(CPUStr, FeaturesStr, *M);
667 
668   if (mc::getExplicitRelaxAll() && codegen::getFileType() != CGFT_ObjectFile)
669     WithColor::warning(errs(), argv[0])
670         << ": warning: ignoring -mc-relax-all because filetype != obj";
671 
672   {
673     raw_pwrite_stream *OS = &Out->os();
674 
675     // Manually do the buffering rather than using buffer_ostream,
676     // so we can memcmp the contents in CompileTwice mode
677     SmallVector<char, 0> Buffer;
678     std::unique_ptr<raw_svector_ostream> BOS;
679     if ((codegen::getFileType() != CGFT_AssemblyFile &&
680          !Out->os().supportsSeeking()) ||
681         CompileTwice) {
682       BOS = std::make_unique<raw_svector_ostream>(Buffer);
683       OS = BOS.get();
684     }
685 
686     const char *argv0 = argv[0];
687     LLVMTargetMachine &LLVMTM = static_cast<LLVMTargetMachine &>(*Target);
688     MachineModuleInfoWrapperPass *MMIWP =
689         new MachineModuleInfoWrapperPass(&LLVMTM);
690 
691     // Construct a custom pass pipeline that starts after instruction
692     // selection.
693     if (!getRunPassNames().empty()) {
694       if (!MIR) {
695         WithColor::warning(errs(), argv[0])
696             << "run-pass is for .mir file only.\n";
697         delete MMIWP;
698         return 1;
699       }
700       TargetPassConfig *PTPC = LLVMTM.createPassConfig(PM);
701       TargetPassConfig &TPC = *PTPC;
702       if (TPC.hasLimitedCodeGenPipeline()) {
703         WithColor::warning(errs(), argv[0])
704             << "run-pass cannot be used with "
705             << TPC.getLimitedCodeGenPipelineReason(" and ") << ".\n";
706         delete PTPC;
707         delete MMIWP;
708         return 1;
709       }
710 
711       TPC.setDisableVerify(NoVerify);
712       PM.add(&TPC);
713       PM.add(MMIWP);
714       TPC.printAndVerify("");
715       for (const std::string &RunPassName : getRunPassNames()) {
716         if (addPass(PM, argv0, RunPassName, TPC))
717           return 1;
718       }
719       TPC.setInitialized();
720       PM.add(createPrintMIRPass(*OS));
721       PM.add(createFreeMachineFunctionPass());
722     } else if (Target->addPassesToEmitFile(
723                    PM, *OS, DwoOut ? &DwoOut->os() : nullptr,
724                    codegen::getFileType(), NoVerify, MMIWP)) {
725       reportError("target does not support generation of this file type");
726     }
727 
728     const_cast<TargetLoweringObjectFile *>(LLVMTM.getObjFileLowering())
729         ->Initialize(MMIWP->getMMI().getContext(), *Target);
730     if (MIR) {
731       assert(MMIWP && "Forgot to create MMIWP?");
732       if (MIR->parseMachineFunctions(*M, MMIWP->getMMI()))
733         return 1;
734     }
735 
736     // Before executing passes, print the final values of the LLVM options.
737     cl::PrintOptionValues();
738 
739     // If requested, run the pass manager over the same module again,
740     // to catch any bugs due to persistent state in the passes. Note that
741     // opt has the same functionality, so it may be worth abstracting this out
742     // in the future.
743     SmallVector<char, 0> CompileTwiceBuffer;
744     if (CompileTwice) {
745       std::unique_ptr<Module> M2(llvm::CloneModule(*M));
746       PM.run(*M2);
747       CompileTwiceBuffer = Buffer;
748       Buffer.clear();
749     }
750 
751     PM.run(*M);
752 
753     auto HasError =
754         ((const LLCDiagnosticHandler *)(Context.getDiagHandlerPtr()))->HasError;
755     if (*HasError)
756       return 1;
757 
758     // Compare the two outputs and make sure they're the same
759     if (CompileTwice) {
760       if (Buffer.size() != CompileTwiceBuffer.size() ||
761           (memcmp(Buffer.data(), CompileTwiceBuffer.data(), Buffer.size()) !=
762            0)) {
763         errs()
764             << "Running the pass manager twice changed the output.\n"
765                "Writing the result of the second run to the specified output\n"
766                "To generate the one-run comparison binary, just run without\n"
767                "the compile-twice option\n";
768         Out->os() << Buffer;
769         Out->keep();
770         return 1;
771       }
772     }
773 
774     if (BOS) {
775       Out->os() << Buffer;
776     }
777   }
778 
779   // Declare success.
780   Out->keep();
781   if (DwoOut)
782     DwoOut->keep();
783 
784   return 0;
785 }
786