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 an assembly file or a relocatable file,
11 // given LLVM bitcode.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #include "NewPMDriver.h"
16 #include "llvm/ADT/STLExtras.h"
17 #include "llvm/ADT/ScopeExit.h"
18 #include "llvm/Analysis/TargetLibraryInfo.h"
19 #include "llvm/CodeGen/CommandFlags.h"
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/LLVMContext.h"
32 #include "llvm/IR/LLVMRemarkStreamer.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/InitializePasses.h"
38 #include "llvm/MC/MCTargetOptionsCommandFlags.h"
39 #include "llvm/MC/TargetRegistry.h"
40 #include "llvm/Pass.h"
41 #include "llvm/Remarks/HotnessThresholdParser.h"
42 #include "llvm/Support/CommandLine.h"
43 #include "llvm/Support/Debug.h"
44 #include "llvm/Support/FileSystem.h"
45 #include "llvm/Support/FormattedStream.h"
46 #include "llvm/Support/InitLLVM.h"
47 #include "llvm/Support/PluginLoader.h"
48 #include "llvm/Support/SourceMgr.h"
49 #include "llvm/Support/TargetSelect.h"
50 #include "llvm/Support/TimeProfiler.h"
51 #include "llvm/Support/ToolOutputFile.h"
52 #include "llvm/Support/WithColor.h"
53 #include "llvm/Target/TargetLoweringObjectFile.h"
54 #include "llvm/Target/TargetMachine.h"
55 #include "llvm/TargetParser/Host.h"
56 #include "llvm/TargetParser/SubtargetFeature.h"
57 #include "llvm/TargetParser/Triple.h"
58 #include "llvm/Transforms/Utils/Cloning.h"
59 #include <memory>
60 #include <optional>
61 using namespace llvm;
62 
63 static codegen::RegisterCodeGenFlags CGF;
64 
65 // General options for llc.  Other pass-specific options are specified
66 // within the corresponding llc passes, and target-specific options
67 // and back-end code generation options are specified with the target machine.
68 //
69 static cl::opt<std::string>
70 InputFilename(cl::Positional, cl::desc("<input bitcode>"), cl::init("-"));
71 
72 static cl::opt<std::string>
73 InputLanguage("x", cl::desc("Input language ('ir' or 'mir')"));
74 
75 static cl::opt<std::string>
76 OutputFilename("o", cl::desc("Output filename"), cl::value_desc("filename"));
77 
78 static cl::opt<std::string>
79     SplitDwarfOutputFile("split-dwarf-output",
80                          cl::desc(".dwo output filename"),
81                          cl::value_desc("filename"));
82 
83 static cl::opt<unsigned>
84 TimeCompilations("time-compilations", cl::Hidden, cl::init(1u),
85                  cl::value_desc("N"),
86                  cl::desc("Repeat compilation N times for timing"));
87 
88 static cl::opt<bool> TimeTrace("time-trace", cl::desc("Record time trace"));
89 
90 static cl::opt<unsigned> TimeTraceGranularity(
91     "time-trace-granularity",
92     cl::desc(
93         "Minimum time granularity (in microseconds) traced by time profiler"),
94     cl::init(500), cl::Hidden);
95 
96 static cl::opt<std::string>
97     TimeTraceFile("time-trace-file",
98                   cl::desc("Specify time trace file destination"),
99                   cl::value_desc("filename"));
100 
101 static cl::opt<std::string>
102     BinutilsVersion("binutils-version", cl::Hidden,
103                     cl::desc("Produced object files can use all ELF features "
104                              "supported by this binutils version and newer."
105                              "If -no-integrated-as is specified, the generated "
106                              "assembly will consider GNU as support."
107                              "'none' means that all ELF features can be used, "
108                              "regardless of binutils support"));
109 
110 static cl::opt<bool>
111     PreserveComments("preserve-as-comments", cl::Hidden,
112                      cl::desc("Preserve Comments in outputted assembly"),
113                      cl::init(true));
114 
115 // Determine optimization level.
116 static cl::opt<char>
117     OptLevel("O",
118              cl::desc("Optimization level. [-O0, -O1, -O2, or -O3] "
119                       "(default = '-O2')"),
120              cl::Prefix, cl::init('2'));
121 
122 static cl::opt<std::string>
123 TargetTriple("mtriple", cl::desc("Override target triple for module"));
124 
125 static cl::opt<std::string> SplitDwarfFile(
126     "split-dwarf-file",
127     cl::desc(
128         "Specify the name of the .dwo file to encode in the DWARF output"));
129 
130 static cl::opt<bool> NoVerify("disable-verify", cl::Hidden,
131                               cl::desc("Do not verify input module"));
132 
133 static cl::opt<bool> DisableSimplifyLibCalls("disable-simplify-libcalls",
134                                              cl::desc("Disable simplify-libcalls"));
135 
136 static cl::opt<bool> ShowMCEncoding("show-mc-encoding", cl::Hidden,
137                                     cl::desc("Show encoding in .s output"));
138 
139 static cl::opt<bool>
140     DwarfDirectory("dwarf-directory", cl::Hidden,
141                    cl::desc("Use .file directives with an explicit directory"),
142                    cl::init(true));
143 
144 static cl::opt<bool> AsmVerbose("asm-verbose",
145                                 cl::desc("Add comments to directives."),
146                                 cl::init(true));
147 
148 static cl::opt<bool>
149     CompileTwice("compile-twice", cl::Hidden,
150                  cl::desc("Run everything twice, re-using the same pass "
151                           "manager and verify the result is the same."),
152                  cl::init(false));
153 
154 static cl::opt<bool> DiscardValueNames(
155     "discard-value-names",
156     cl::desc("Discard names from Value (other than GlobalValue)."),
157     cl::init(false), cl::Hidden);
158 
159 static cl::list<std::string> IncludeDirs("I", cl::desc("include search path"));
160 
161 static cl::opt<bool> RemarksWithHotness(
162     "pass-remarks-with-hotness",
163     cl::desc("With PGO, include profile count in optimization remarks"),
164     cl::Hidden);
165 
166 static cl::opt<std::optional<uint64_t>, false, remarks::HotnessThresholdParser>
167     RemarksHotnessThreshold(
168         "pass-remarks-hotness-threshold",
169         cl::desc("Minimum profile count required for "
170                  "an optimization remark to be output. "
171                  "Use 'auto' to apply the threshold from profile summary."),
172         cl::value_desc("N or 'auto'"), cl::init(0), cl::Hidden);
173 
174 static cl::opt<std::string>
175     RemarksFilename("pass-remarks-output",
176                     cl::desc("Output filename for pass remarks"),
177                     cl::value_desc("filename"));
178 
179 static cl::opt<std::string>
180     RemarksPasses("pass-remarks-filter",
181                   cl::desc("Only record optimization remarks from passes whose "
182                            "names match the given regular expression"),
183                   cl::value_desc("regex"));
184 
185 static cl::opt<std::string> RemarksFormat(
186     "pass-remarks-format",
187     cl::desc("The format used for serializing remarks (default: YAML)"),
188     cl::value_desc("format"), cl::init("yaml"));
189 
190 static cl::opt<bool> EnableNewPassManager(
191     "enable-new-pm", cl::desc("Enable the new pass manager"), cl::init(false));
192 
193 // This flag specifies a textual description of the optimization pass pipeline
194 // to run over the module. This flag switches opt to use the new pass manager
195 // infrastructure, completely disabling all of the flags specific to the old
196 // pass management.
197 static cl::opt<std::string> PassPipeline(
198     "passes",
199     cl::desc(
200         "A textual description of the pass pipeline. To have analysis passes "
201         "available before a certain pass, add 'require<foo-analysis>'."));
202 static cl::alias PassPipeline2("p", cl::aliasopt(PassPipeline),
203                                cl::desc("Alias for -passes"));
204 
205 static cl::opt<bool> TryUseNewDbgInfoFormat(
206     "try-experimental-debuginfo-iterators",
207     cl::desc("Enable debuginfo iterator positions, if they're built in"),
208     cl::init(false), cl::Hidden);
209 
210 extern cl::opt<bool> UseNewDbgInfoFormat;
211 
212 namespace {
213 
214 std::vector<std::string> &getRunPassNames() {
215   static std::vector<std::string> RunPassNames;
216   return RunPassNames;
217 }
218 
219 struct RunPassOption {
220   void operator=(const std::string &Val) const {
221     if (Val.empty())
222       return;
223     SmallVector<StringRef, 8> PassNames;
224     StringRef(Val).split(PassNames, ',', -1, false);
225     for (auto PassName : PassNames)
226       getRunPassNames().push_back(std::string(PassName));
227   }
228 };
229 } // namespace
230 
231 static RunPassOption RunPassOpt;
232 
233 static cl::opt<RunPassOption, true, cl::parser<std::string>> RunPass(
234     "run-pass",
235     cl::desc("Run compiler only for specified passes (comma separated list)"),
236     cl::value_desc("pass-name"), cl::location(RunPassOpt));
237 
238 static int compileModule(char **, LLVMContext &);
239 
240 [[noreturn]] static void reportError(Twine Msg, StringRef Filename = "") {
241   SmallString<256> Prefix;
242   if (!Filename.empty()) {
243     if (Filename == "-")
244       Filename = "<stdin>";
245     ("'" + Twine(Filename) + "': ").toStringRef(Prefix);
246   }
247   WithColor::error(errs(), "llc") << Prefix << Msg << "\n";
248   exit(1);
249 }
250 
251 [[noreturn]] static void reportError(Error Err, StringRef Filename) {
252   assert(Err);
253   handleAllErrors(createFileError(Filename, std::move(Err)),
254                   [&](const ErrorInfoBase &EI) { reportError(EI.message()); });
255   llvm_unreachable("reportError() should not return");
256 }
257 
258 static std::unique_ptr<ToolOutputFile> GetOutputStream(const char *TargetName,
259                                                        Triple::OSType OS,
260                                                        const char *ProgName) {
261   // If we don't yet have an output filename, make one.
262   if (OutputFilename.empty()) {
263     if (InputFilename == "-")
264       OutputFilename = "-";
265     else {
266       // If InputFilename ends in .bc or .ll, remove it.
267       StringRef IFN = InputFilename;
268       if (IFN.ends_with(".bc") || IFN.ends_with(".ll"))
269         OutputFilename = std::string(IFN.drop_back(3));
270       else if (IFN.ends_with(".mir"))
271         OutputFilename = std::string(IFN.drop_back(4));
272       else
273         OutputFilename = std::string(IFN);
274 
275       switch (codegen::getFileType()) {
276       case CodeGenFileType::AssemblyFile:
277         OutputFilename += ".s";
278         break;
279       case CodeGenFileType::ObjectFile:
280         if (OS == Triple::Win32)
281           OutputFilename += ".obj";
282         else
283           OutputFilename += ".o";
284         break;
285       case CodeGenFileType::Null:
286         OutputFilename = "-";
287         break;
288       }
289     }
290   }
291 
292   // Decide if we need "binary" output.
293   bool Binary = false;
294   switch (codegen::getFileType()) {
295   case CodeGenFileType::AssemblyFile:
296     break;
297   case CodeGenFileType::ObjectFile:
298   case CodeGenFileType::Null:
299     Binary = true;
300     break;
301   }
302 
303   // Open the file.
304   std::error_code EC;
305   sys::fs::OpenFlags OpenFlags = sys::fs::OF_None;
306   if (!Binary)
307     OpenFlags |= sys::fs::OF_TextWithCRLF;
308   auto FDOut = std::make_unique<ToolOutputFile>(OutputFilename, EC, OpenFlags);
309   if (EC) {
310     reportError(EC.message());
311     return nullptr;
312   }
313 
314   return FDOut;
315 }
316 
317 // main - Entry point for the llc compiler.
318 //
319 int main(int argc, char **argv) {
320   InitLLVM X(argc, argv);
321 
322   // Enable debug stream buffering.
323   EnableDebugBuffering = true;
324 
325   // Initialize targets first, so that --version shows registered targets.
326   InitializeAllTargets();
327   InitializeAllTargetMCs();
328   InitializeAllAsmPrinters();
329   InitializeAllAsmParsers();
330 
331   // Initialize codegen and IR passes used by llc so that the -print-after,
332   // -print-before, and -stop-after options work.
333   PassRegistry *Registry = PassRegistry::getPassRegistry();
334   initializeCore(*Registry);
335   initializeCodeGen(*Registry);
336   initializeLoopStrengthReducePass(*Registry);
337   initializeLowerIntrinsicsPass(*Registry);
338   initializeUnreachableBlockElimLegacyPassPass(*Registry);
339   initializeConstantHoistingLegacyPassPass(*Registry);
340   initializeScalarOpts(*Registry);
341   initializeVectorization(*Registry);
342   initializeScalarizeMaskedMemIntrinLegacyPassPass(*Registry);
343   initializeExpandReductionsPass(*Registry);
344   initializeExpandVectorPredicationPass(*Registry);
345   initializeHardwareLoopsLegacyPass(*Registry);
346   initializeTransformUtils(*Registry);
347   initializeReplaceWithVeclibLegacyPass(*Registry);
348   initializeTLSVariableHoistLegacyPassPass(*Registry);
349 
350   // Initialize debugging passes.
351   initializeScavengerTestPass(*Registry);
352 
353   // Register the Target and CPU printer for --version.
354   cl::AddExtraVersionPrinter(sys::printDefaultTargetAndDetectedCPU);
355   // Register the target printer for --version.
356   cl::AddExtraVersionPrinter(TargetRegistry::printRegisteredTargetsForVersion);
357 
358   cl::ParseCommandLineOptions(argc, argv, "llvm system compiler\n");
359 
360   if (!PassPipeline.empty() && !getRunPassNames().empty()) {
361     errs() << "The `llc -run-pass=...` syntax for the new pass manager is "
362               "not supported, please use `llc -passes=<pipeline>` (or the `-p` "
363               "alias for a more concise version).\n";
364     return 1;
365   }
366 
367   // RemoveDIs debug-info transition: tests may request that we /try/ to use the
368   // new debug-info format, if it's built in.
369 #ifdef EXPERIMENTAL_DEBUGINFO_ITERATORS
370   if (TryUseNewDbgInfoFormat) {
371     // If LLVM was built with support for this, turn the new debug-info format
372     // on.
373     UseNewDbgInfoFormat = true;
374   }
375 #endif
376   (void)TryUseNewDbgInfoFormat;
377 
378   if (TimeTrace)
379     timeTraceProfilerInitialize(TimeTraceGranularity, argv[0]);
380   auto TimeTraceScopeExit = make_scope_exit([]() {
381     if (TimeTrace) {
382       if (auto E = timeTraceProfilerWrite(TimeTraceFile, OutputFilename)) {
383         handleAllErrors(std::move(E), [&](const StringError &SE) {
384           errs() << SE.getMessage() << "\n";
385         });
386         return;
387       }
388       timeTraceProfilerCleanup();
389     }
390   });
391 
392   LLVMContext Context;
393   Context.setDiscardValueNames(DiscardValueNames);
394 
395   // Set a diagnostic handler that doesn't exit on the first error
396   Context.setDiagnosticHandler(std::make_unique<LLCDiagnosticHandler>());
397 
398   Expected<std::unique_ptr<ToolOutputFile>> RemarksFileOrErr =
399       setupLLVMOptimizationRemarks(Context, RemarksFilename, RemarksPasses,
400                                    RemarksFormat, RemarksWithHotness,
401                                    RemarksHotnessThreshold);
402   if (Error E = RemarksFileOrErr.takeError())
403     reportError(std::move(E), RemarksFilename);
404   std::unique_ptr<ToolOutputFile> RemarksFile = std::move(*RemarksFileOrErr);
405 
406   if (InputLanguage != "" && InputLanguage != "ir" && InputLanguage != "mir")
407     reportError("input language must be '', 'IR' or 'MIR'");
408 
409   // Compile the module TimeCompilations times to give better compile time
410   // metrics.
411   for (unsigned I = TimeCompilations; I; --I)
412     if (int RetVal = compileModule(argv, Context))
413       return RetVal;
414 
415   if (RemarksFile)
416     RemarksFile->keep();
417   return 0;
418 }
419 
420 static bool addPass(PassManagerBase &PM, const char *argv0,
421                     StringRef PassName, TargetPassConfig &TPC) {
422   if (PassName == "none")
423     return false;
424 
425   const PassRegistry *PR = PassRegistry::getPassRegistry();
426   const PassInfo *PI = PR->getPassInfo(PassName);
427   if (!PI) {
428     WithColor::error(errs(), argv0)
429         << "run-pass " << PassName << " is not registered.\n";
430     return true;
431   }
432 
433   Pass *P;
434   if (PI->getNormalCtor())
435     P = PI->getNormalCtor()();
436   else {
437     WithColor::error(errs(), argv0)
438         << "cannot create pass: " << PI->getPassName() << "\n";
439     return true;
440   }
441   std::string Banner = std::string("After ") + std::string(P->getPassName());
442   TPC.addMachinePrePasses();
443   PM.add(P);
444   TPC.addMachinePostPasses(Banner);
445 
446   return false;
447 }
448 
449 static int compileModule(char **argv, LLVMContext &Context) {
450   // Load the module to be compiled...
451   SMDiagnostic Err;
452   std::unique_ptr<Module> M;
453   std::unique_ptr<MIRParser> MIR;
454   Triple TheTriple;
455   std::string CPUStr = codegen::getCPUStr(),
456               FeaturesStr = codegen::getFeaturesStr();
457 
458   // Set attributes on functions as loaded from MIR from command line arguments.
459   auto setMIRFunctionAttributes = [&CPUStr, &FeaturesStr](Function &F) {
460     codegen::setFunctionAttributes(CPUStr, FeaturesStr, F);
461   };
462 
463   auto MAttrs = codegen::getMAttrs();
464   bool SkipModule =
465       CPUStr == "help" || (!MAttrs.empty() && MAttrs.front() == "help");
466 
467   CodeGenOptLevel OLvl;
468   if (auto Level = CodeGenOpt::parseLevel(OptLevel)) {
469     OLvl = *Level;
470   } else {
471     WithColor::error(errs(), argv[0]) << "invalid optimization level.\n";
472     return 1;
473   }
474 
475   // Parse 'none' or '$major.$minor'. Disallow -binutils-version=0 because we
476   // use that to indicate the MC default.
477   if (!BinutilsVersion.empty() && BinutilsVersion != "none") {
478     StringRef V = BinutilsVersion.getValue();
479     unsigned Num;
480     if (V.consumeInteger(10, Num) || Num == 0 ||
481         !(V.empty() ||
482           (V.consume_front(".") && !V.consumeInteger(10, Num) && V.empty()))) {
483       WithColor::error(errs(), argv[0])
484           << "invalid -binutils-version, accepting 'none' or major.minor\n";
485       return 1;
486     }
487   }
488   TargetOptions Options;
489   auto InitializeOptions = [&](const Triple &TheTriple) {
490     Options = codegen::InitTargetOptionsFromCodeGenFlags(TheTriple);
491 
492     if (Options.XCOFFReadOnlyPointers) {
493       if (!TheTriple.isOSAIX())
494         reportError("-mxcoff-roptr option is only supported on AIX",
495                     InputFilename);
496 
497       // Since the storage mapping class is specified per csect,
498       // without using data sections, it is less effective to use read-only
499       // pointers. Using read-only pointers may cause other RO variables in the
500       // same csect to become RW when the linker acts upon `-bforceimprw`;
501       // therefore, we require that separate data sections are used in the
502       // presence of ReadOnlyPointers. We respect the setting of data-sections
503       // since we have not found reasons to do otherwise that overcome the user
504       // surprise of not respecting the setting.
505       if (!Options.DataSections)
506         reportError("-mxcoff-roptr option must be used with -data-sections",
507                     InputFilename);
508     }
509 
510     Options.BinutilsVersion =
511         TargetMachine::parseBinutilsVersion(BinutilsVersion);
512     Options.MCOptions.ShowMCEncoding = ShowMCEncoding;
513     Options.MCOptions.AsmVerbose = AsmVerbose;
514     Options.MCOptions.PreserveAsmComments = PreserveComments;
515     Options.MCOptions.IASSearchPaths = IncludeDirs;
516     Options.MCOptions.SplitDwarfFile = SplitDwarfFile;
517     if (DwarfDirectory.getPosition()) {
518       Options.MCOptions.MCUseDwarfDirectory =
519           DwarfDirectory ? MCTargetOptions::EnableDwarfDirectory
520                          : MCTargetOptions::DisableDwarfDirectory;
521     } else {
522       // -dwarf-directory is not set explicitly. Some assemblers
523       // (e.g. GNU as or ptxas) do not support `.file directory'
524       // syntax prior to DWARFv5. Let the target decide the default
525       // value.
526       Options.MCOptions.MCUseDwarfDirectory =
527           MCTargetOptions::DefaultDwarfDirectory;
528     }
529   };
530 
531   std::optional<Reloc::Model> RM = codegen::getExplicitRelocModel();
532   std::optional<CodeModel::Model> CM = codegen::getExplicitCodeModel();
533 
534   const Target *TheTarget = nullptr;
535   std::unique_ptr<TargetMachine> Target;
536 
537   // If user just wants to list available options, skip module loading
538   if (!SkipModule) {
539     auto SetDataLayout = [&](StringRef DataLayoutTargetTriple,
540                              StringRef OldDLStr) -> std::optional<std::string> {
541       // If we are supposed to override the target triple, do so now.
542       std::string IRTargetTriple = DataLayoutTargetTriple.str();
543       if (!TargetTriple.empty())
544         IRTargetTriple = Triple::normalize(TargetTriple);
545       TheTriple = Triple(IRTargetTriple);
546       if (TheTriple.getTriple().empty())
547         TheTriple.setTriple(sys::getDefaultTargetTriple());
548 
549       std::string Error;
550       TheTarget =
551           TargetRegistry::lookupTarget(codegen::getMArch(), TheTriple, Error);
552       if (!TheTarget) {
553         WithColor::error(errs(), argv[0]) << Error;
554         exit(1);
555       }
556 
557       InitializeOptions(TheTriple);
558       Target = std::unique_ptr<TargetMachine>(TheTarget->createTargetMachine(
559           TheTriple.getTriple(), CPUStr, FeaturesStr, Options, RM, CM, OLvl));
560       assert(Target && "Could not allocate target machine!");
561 
562       return Target->createDataLayout().getStringRepresentation();
563     };
564     if (InputLanguage == "mir" ||
565         (InputLanguage == "" && StringRef(InputFilename).ends_with(".mir"))) {
566       MIR = createMIRParserFromFile(InputFilename, Err, Context,
567                                     setMIRFunctionAttributes);
568       if (MIR)
569         M = MIR->parseIRModule(SetDataLayout);
570     } else {
571       M = parseIRFile(InputFilename, Err, Context,
572                       ParserCallbacks(SetDataLayout));
573     }
574     if (!M) {
575       Err.print(argv[0], WithColor::error(errs(), argv[0]));
576       return 1;
577     }
578     if (!TargetTriple.empty())
579       M->setTargetTriple(Triple::normalize(TargetTriple));
580 
581     std::optional<CodeModel::Model> CM_IR = M->getCodeModel();
582     if (!CM && CM_IR)
583       Target->setCodeModel(*CM_IR);
584     if (std::optional<uint64_t> LDT = codegen::getExplicitLargeDataThreshold())
585       Target->setLargeDataThreshold(*LDT);
586   } else {
587     TheTriple = Triple(Triple::normalize(TargetTriple));
588     if (TheTriple.getTriple().empty())
589       TheTriple.setTriple(sys::getDefaultTargetTriple());
590 
591     // Get the target specific parser.
592     std::string Error;
593     TheTarget =
594         TargetRegistry::lookupTarget(codegen::getMArch(), TheTriple, Error);
595     if (!TheTarget) {
596       WithColor::error(errs(), argv[0]) << Error;
597       return 1;
598     }
599 
600     InitializeOptions(TheTriple);
601     Target = std::unique_ptr<TargetMachine>(TheTarget->createTargetMachine(
602         TheTriple.getTriple(), CPUStr, FeaturesStr, Options, RM, CM, OLvl));
603     assert(Target && "Could not allocate target machine!");
604 
605     // If we don't have a module then just exit now. We do this down
606     // here since the CPU/Feature help is underneath the target machine
607     // creation.
608     return 0;
609   }
610 
611   assert(M && "Should have exited if we didn't have a module!");
612   if (codegen::getFloatABIForCalls() != FloatABI::Default)
613     Target->Options.FloatABIType = codegen::getFloatABIForCalls();
614 
615   // Figure out where we are going to send the output.
616   std::unique_ptr<ToolOutputFile> Out =
617       GetOutputStream(TheTarget->getName(), TheTriple.getOS(), argv[0]);
618   if (!Out) return 1;
619 
620   // Ensure the filename is passed down to CodeViewDebug.
621   Target->Options.ObjectFilenameForDebug = Out->outputFilename();
622 
623   std::unique_ptr<ToolOutputFile> DwoOut;
624   if (!SplitDwarfOutputFile.empty()) {
625     std::error_code EC;
626     DwoOut = std::make_unique<ToolOutputFile>(SplitDwarfOutputFile, EC,
627                                                sys::fs::OF_None);
628     if (EC)
629       reportError(EC.message(), SplitDwarfOutputFile);
630   }
631 
632   // Add an appropriate TargetLibraryInfo pass for the module's triple.
633   TargetLibraryInfoImpl TLII(Triple(M->getTargetTriple()));
634 
635   // The -disable-simplify-libcalls flag actually disables all builtin optzns.
636   if (DisableSimplifyLibCalls)
637     TLII.disableAllFunctions();
638 
639   // Verify module immediately to catch problems before doInitialization() is
640   // called on any passes.
641   if (!NoVerify && verifyModule(*M, &errs()))
642     reportError("input module cannot be verified", InputFilename);
643 
644   // Override function attributes based on CPUStr, FeaturesStr, and command line
645   // flags.
646   codegen::setFunctionAttributes(CPUStr, FeaturesStr, *M);
647 
648   if (mc::getExplicitRelaxAll() &&
649       codegen::getFileType() != CodeGenFileType::ObjectFile)
650     WithColor::warning(errs(), argv[0])
651         << ": warning: ignoring -mc-relax-all because filetype != obj";
652 
653   if (EnableNewPassManager || !PassPipeline.empty()) {
654     return compileModuleWithNewPM(argv[0], std::move(M), std::move(MIR),
655                                   std::move(Target), std::move(Out),
656                                   std::move(DwoOut), Context, TLII, NoVerify,
657                                   PassPipeline, codegen::getFileType());
658   }
659 
660   // Build up all of the passes that we want to do to the module.
661   legacy::PassManager PM;
662   PM.add(new TargetLibraryInfoWrapperPass(TLII));
663 
664   {
665     raw_pwrite_stream *OS = &Out->os();
666 
667     // Manually do the buffering rather than using buffer_ostream,
668     // so we can memcmp the contents in CompileTwice mode
669     SmallVector<char, 0> Buffer;
670     std::unique_ptr<raw_svector_ostream> BOS;
671     if ((codegen::getFileType() != CodeGenFileType::AssemblyFile &&
672          !Out->os().supportsSeeking()) ||
673         CompileTwice) {
674       BOS = std::make_unique<raw_svector_ostream>(Buffer);
675       OS = BOS.get();
676     }
677 
678     const char *argv0 = argv[0];
679     LLVMTargetMachine &LLVMTM = static_cast<LLVMTargetMachine &>(*Target);
680     MachineModuleInfoWrapperPass *MMIWP =
681         new MachineModuleInfoWrapperPass(&LLVMTM);
682 
683     // Construct a custom pass pipeline that starts after instruction
684     // selection.
685     if (!getRunPassNames().empty()) {
686       if (!MIR) {
687         WithColor::warning(errs(), argv[0])
688             << "run-pass is for .mir file only.\n";
689         delete MMIWP;
690         return 1;
691       }
692       TargetPassConfig *PTPC = LLVMTM.createPassConfig(PM);
693       TargetPassConfig &TPC = *PTPC;
694       if (TPC.hasLimitedCodeGenPipeline()) {
695         WithColor::warning(errs(), argv[0])
696             << "run-pass cannot be used with "
697             << TPC.getLimitedCodeGenPipelineReason() << ".\n";
698         delete PTPC;
699         delete MMIWP;
700         return 1;
701       }
702 
703       TPC.setDisableVerify(NoVerify);
704       PM.add(&TPC);
705       PM.add(MMIWP);
706       TPC.printAndVerify("");
707       for (const std::string &RunPassName : getRunPassNames()) {
708         if (addPass(PM, argv0, RunPassName, TPC))
709           return 1;
710       }
711       TPC.setInitialized();
712       PM.add(createPrintMIRPass(*OS));
713       PM.add(createFreeMachineFunctionPass());
714     } else if (Target->addPassesToEmitFile(
715                    PM, *OS, DwoOut ? &DwoOut->os() : nullptr,
716                    codegen::getFileType(), NoVerify, MMIWP)) {
717       reportError("target does not support generation of this file type");
718     }
719 
720     const_cast<TargetLoweringObjectFile *>(LLVMTM.getObjFileLowering())
721         ->Initialize(MMIWP->getMMI().getContext(), *Target);
722     if (MIR) {
723       assert(MMIWP && "Forgot to create MMIWP?");
724       if (MIR->parseMachineFunctions(*M, MMIWP->getMMI()))
725         return 1;
726     }
727 
728     // Before executing passes, print the final values of the LLVM options.
729     cl::PrintOptionValues();
730 
731     // If requested, run the pass manager over the same module again,
732     // to catch any bugs due to persistent state in the passes. Note that
733     // opt has the same functionality, so it may be worth abstracting this out
734     // in the future.
735     SmallVector<char, 0> CompileTwiceBuffer;
736     if (CompileTwice) {
737       std::unique_ptr<Module> M2(llvm::CloneModule(*M));
738       PM.run(*M2);
739       CompileTwiceBuffer = Buffer;
740       Buffer.clear();
741     }
742 
743     PM.run(*M);
744 
745     if (Context.getDiagHandlerPtr()->HasErrors)
746       return 1;
747 
748     // Compare the two outputs and make sure they're the same
749     if (CompileTwice) {
750       if (Buffer.size() != CompileTwiceBuffer.size() ||
751           (memcmp(Buffer.data(), CompileTwiceBuffer.data(), Buffer.size()) !=
752            0)) {
753         errs()
754             << "Running the pass manager twice changed the output.\n"
755                "Writing the result of the second run to the specified output\n"
756                "To generate the one-run comparison binary, just run without\n"
757                "the compile-twice option\n";
758         Out->os() << Buffer;
759         Out->keep();
760         return 1;
761       }
762     }
763 
764     if (BOS) {
765       Out->os() << Buffer;
766     }
767   }
768 
769   // Declare success.
770   Out->keep();
771   if (DwoOut)
772     DwoOut->keep();
773 
774   return 0;
775 }
776