1 //===- TargetPassConfig.cpp - Target independent code generation passes ---===//
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 file defines interfaces to access the target independent code
10 // generation passes provided by the LLVM backend.
11 //
12 //===---------------------------------------------------------------------===//
13 
14 #include "llvm/CodeGen/TargetPassConfig.h"
15 #include "llvm/ADT/DenseMap.h"
16 #include "llvm/ADT/SmallVector.h"
17 #include "llvm/ADT/StringRef.h"
18 #include "llvm/Analysis/BasicAliasAnalysis.h"
19 #include "llvm/Analysis/CFLAndersAliasAnalysis.h"
20 #include "llvm/Analysis/CFLSteensAliasAnalysis.h"
21 #include "llvm/Analysis/CallGraphSCCPass.h"
22 #include "llvm/Analysis/ScopedNoAliasAA.h"
23 #include "llvm/Analysis/TargetTransformInfo.h"
24 #include "llvm/Analysis/TypeBasedAliasAnalysis.h"
25 #include "llvm/CodeGen/CSEConfigBase.h"
26 #include "llvm/CodeGen/MachineFunctionPass.h"
27 #include "llvm/CodeGen/MachinePassRegistry.h"
28 #include "llvm/CodeGen/Passes.h"
29 #include "llvm/CodeGen/RegAllocRegistry.h"
30 #include "llvm/IR/IRPrintingPasses.h"
31 #include "llvm/IR/LegacyPassManager.h"
32 #include "llvm/IR/Verifier.h"
33 #include "llvm/InitializePasses.h"
34 #include "llvm/MC/MCAsmInfo.h"
35 #include "llvm/MC/MCTargetOptions.h"
36 #include "llvm/Pass.h"
37 #include "llvm/Support/CodeGen.h"
38 #include "llvm/Support/CommandLine.h"
39 #include "llvm/Support/Compiler.h"
40 #include "llvm/Support/Debug.h"
41 #include "llvm/Support/ErrorHandling.h"
42 #include "llvm/Support/SaveAndRestore.h"
43 #include "llvm/Support/Threading.h"
44 #include "llvm/Target/TargetMachine.h"
45 #include "llvm/Transforms/Scalar.h"
46 #include "llvm/Transforms/Utils.h"
47 #include "llvm/Transforms/Utils/SymbolRewriter.h"
48 #include <cassert>
49 #include <string>
50 
51 using namespace llvm;
52 
53 static cl::opt<bool>
54     EnableIPRA("enable-ipra", cl::init(false), cl::Hidden,
55                cl::desc("Enable interprocedural register allocation "
56                         "to reduce load/store at procedure calls."));
57 static cl::opt<bool> DisablePostRASched("disable-post-ra", cl::Hidden,
58     cl::desc("Disable Post Regalloc Scheduler"));
59 static cl::opt<bool> DisableBranchFold("disable-branch-fold", cl::Hidden,
60     cl::desc("Disable branch folding"));
61 static cl::opt<bool> DisableTailDuplicate("disable-tail-duplicate", cl::Hidden,
62     cl::desc("Disable tail duplication"));
63 static cl::opt<bool> DisableEarlyTailDup("disable-early-taildup", cl::Hidden,
64     cl::desc("Disable pre-register allocation tail duplication"));
65 static cl::opt<bool> DisableBlockPlacement("disable-block-placement",
66     cl::Hidden, cl::desc("Disable probability-driven block placement"));
67 static cl::opt<bool> EnableBlockPlacementStats("enable-block-placement-stats",
68     cl::Hidden, cl::desc("Collect probability-driven block placement stats"));
69 static cl::opt<bool> DisableSSC("disable-ssc", cl::Hidden,
70     cl::desc("Disable Stack Slot Coloring"));
71 static cl::opt<bool> DisableMachineDCE("disable-machine-dce", cl::Hidden,
72     cl::desc("Disable Machine Dead Code Elimination"));
73 static cl::opt<bool> DisableEarlyIfConversion("disable-early-ifcvt", cl::Hidden,
74     cl::desc("Disable Early If-conversion"));
75 static cl::opt<bool> DisableMachineLICM("disable-machine-licm", cl::Hidden,
76     cl::desc("Disable Machine LICM"));
77 static cl::opt<bool> DisableMachineCSE("disable-machine-cse", cl::Hidden,
78     cl::desc("Disable Machine Common Subexpression Elimination"));
79 static cl::opt<cl::boolOrDefault> OptimizeRegAlloc(
80     "optimize-regalloc", cl::Hidden,
81     cl::desc("Enable optimized register allocation compilation path."));
82 static cl::opt<bool> DisablePostRAMachineLICM("disable-postra-machine-licm",
83     cl::Hidden,
84     cl::desc("Disable Machine LICM"));
85 static cl::opt<bool> DisableMachineSink("disable-machine-sink", cl::Hidden,
86     cl::desc("Disable Machine Sinking"));
87 static cl::opt<bool> DisablePostRAMachineSink("disable-postra-machine-sink",
88     cl::Hidden,
89     cl::desc("Disable PostRA Machine Sinking"));
90 static cl::opt<bool> DisableLSR("disable-lsr", cl::Hidden,
91     cl::desc("Disable Loop Strength Reduction Pass"));
92 static cl::opt<bool> DisableConstantHoisting("disable-constant-hoisting",
93     cl::Hidden, cl::desc("Disable ConstantHoisting"));
94 static cl::opt<bool> DisableCGP("disable-cgp", cl::Hidden,
95     cl::desc("Disable Codegen Prepare"));
96 static cl::opt<bool> DisableCopyProp("disable-copyprop", cl::Hidden,
97     cl::desc("Disable Copy Propagation pass"));
98 static cl::opt<bool> DisablePartialLibcallInlining("disable-partial-libcall-inlining",
99     cl::Hidden, cl::desc("Disable Partial Libcall Inlining"));
100 static cl::opt<bool> EnableImplicitNullChecks(
101     "enable-implicit-null-checks",
102     cl::desc("Fold null checks into faulting memory operations"),
103     cl::init(false), cl::Hidden);
104 static cl::opt<bool> DisableMergeICmps("disable-mergeicmps",
105     cl::desc("Disable MergeICmps Pass"),
106     cl::init(false), cl::Hidden);
107 static cl::opt<bool> PrintLSR("print-lsr-output", cl::Hidden,
108     cl::desc("Print LLVM IR produced by the loop-reduce pass"));
109 static cl::opt<bool> PrintISelInput("print-isel-input", cl::Hidden,
110     cl::desc("Print LLVM IR input to isel pass"));
111 static cl::opt<bool> PrintGCInfo("print-gc", cl::Hidden,
112     cl::desc("Dump garbage collector data"));
113 static cl::opt<cl::boolOrDefault>
114     VerifyMachineCode("verify-machineinstrs", cl::Hidden,
115                       cl::desc("Verify generated machine code"),
116                       cl::ZeroOrMore);
117 enum RunOutliner { AlwaysOutline, NeverOutline, TargetDefault };
118 // Enable or disable the MachineOutliner.
119 static cl::opt<RunOutliner> EnableMachineOutliner(
120     "enable-machine-outliner", cl::desc("Enable the machine outliner"),
121     cl::Hidden, cl::ValueOptional, cl::init(TargetDefault),
122     cl::values(clEnumValN(AlwaysOutline, "always",
123                           "Run on all functions guaranteed to be beneficial"),
124                clEnumValN(NeverOutline, "never", "Disable all outlining"),
125                // Sentinel value for unspecified option.
126                clEnumValN(AlwaysOutline, "", "")));
127 // Enable or disable FastISel. Both options are needed, because
128 // FastISel is enabled by default with -fast, and we wish to be
129 // able to enable or disable fast-isel independently from -O0.
130 static cl::opt<cl::boolOrDefault>
131 EnableFastISelOption("fast-isel", cl::Hidden,
132   cl::desc("Enable the \"fast\" instruction selector"));
133 
134 static cl::opt<cl::boolOrDefault> EnableGlobalISelOption(
135     "global-isel", cl::Hidden,
136     cl::desc("Enable the \"global\" instruction selector"));
137 
138 static cl::opt<std::string> PrintMachineInstrs(
139     "print-machineinstrs", cl::ValueOptional, cl::desc("Print machine instrs"),
140     cl::value_desc("pass-name"), cl::init("option-unspecified"), cl::Hidden);
141 
142 static cl::opt<GlobalISelAbortMode> EnableGlobalISelAbort(
143     "global-isel-abort", cl::Hidden,
144     cl::desc("Enable abort calls when \"global\" instruction selection "
145              "fails to lower/select an instruction"),
146     cl::values(
147         clEnumValN(GlobalISelAbortMode::Disable, "0", "Disable the abort"),
148         clEnumValN(GlobalISelAbortMode::Enable, "1", "Enable the abort"),
149         clEnumValN(GlobalISelAbortMode::DisableWithDiag, "2",
150                    "Disable the abort but emit a diagnostic on failure")));
151 
152 // Temporary option to allow experimenting with MachineScheduler as a post-RA
153 // scheduler. Targets can "properly" enable this with
154 // substitutePass(&PostRASchedulerID, &PostMachineSchedulerID).
155 // Targets can return true in targetSchedulesPostRAScheduling() and
156 // insert a PostRA scheduling pass wherever it wants.
157 static cl::opt<bool> MISchedPostRA(
158     "misched-postra", cl::Hidden,
159     cl::desc(
160         "Run MachineScheduler post regalloc (independent of preRA sched)"));
161 
162 // Experimental option to run live interval analysis early.
163 static cl::opt<bool> EarlyLiveIntervals("early-live-intervals", cl::Hidden,
164     cl::desc("Run live interval analysis earlier in the pipeline"));
165 
166 // Experimental option to use CFL-AA in codegen
167 enum class CFLAAType { None, Steensgaard, Andersen, Both };
168 static cl::opt<CFLAAType> UseCFLAA(
169     "use-cfl-aa-in-codegen", cl::init(CFLAAType::None), cl::Hidden,
170     cl::desc("Enable the new, experimental CFL alias analysis in CodeGen"),
171     cl::values(clEnumValN(CFLAAType::None, "none", "Disable CFL-AA"),
172                clEnumValN(CFLAAType::Steensgaard, "steens",
173                           "Enable unification-based CFL-AA"),
174                clEnumValN(CFLAAType::Andersen, "anders",
175                           "Enable inclusion-based CFL-AA"),
176                clEnumValN(CFLAAType::Both, "both",
177                           "Enable both variants of CFL-AA")));
178 
179 /// Option names for limiting the codegen pipeline.
180 /// Those are used in error reporting and we didn't want
181 /// to duplicate their names all over the place.
182 static const char StartAfterOptName[] = "start-after";
183 static const char StartBeforeOptName[] = "start-before";
184 static const char StopAfterOptName[] = "stop-after";
185 static const char StopBeforeOptName[] = "stop-before";
186 
187 static cl::opt<std::string>
188     StartAfterOpt(StringRef(StartAfterOptName),
189                   cl::desc("Resume compilation after a specific pass"),
190                   cl::value_desc("pass-name"), cl::init(""), cl::Hidden);
191 
192 static cl::opt<std::string>
193     StartBeforeOpt(StringRef(StartBeforeOptName),
194                    cl::desc("Resume compilation before a specific pass"),
195                    cl::value_desc("pass-name"), cl::init(""), cl::Hidden);
196 
197 static cl::opt<std::string>
198     StopAfterOpt(StringRef(StopAfterOptName),
199                  cl::desc("Stop compilation after a specific pass"),
200                  cl::value_desc("pass-name"), cl::init(""), cl::Hidden);
201 
202 static cl::opt<std::string>
203     StopBeforeOpt(StringRef(StopBeforeOptName),
204                   cl::desc("Stop compilation before a specific pass"),
205                   cl::value_desc("pass-name"), cl::init(""), cl::Hidden);
206 
207 /// Allow standard passes to be disabled by command line options. This supports
208 /// simple binary flags that either suppress the pass or do nothing.
209 /// i.e. -disable-mypass=false has no effect.
210 /// These should be converted to boolOrDefault in order to use applyOverride.
211 static IdentifyingPassPtr applyDisable(IdentifyingPassPtr PassID,
212                                        bool Override) {
213   if (Override)
214     return IdentifyingPassPtr();
215   return PassID;
216 }
217 
218 /// Allow standard passes to be disabled by the command line, regardless of who
219 /// is adding the pass.
220 ///
221 /// StandardID is the pass identified in the standard pass pipeline and provided
222 /// to addPass(). It may be a target-specific ID in the case that the target
223 /// directly adds its own pass, but in that case we harmlessly fall through.
224 ///
225 /// TargetID is the pass that the target has configured to override StandardID.
226 ///
227 /// StandardID may be a pseudo ID. In that case TargetID is the name of the real
228 /// pass to run. This allows multiple options to control a single pass depending
229 /// on where in the pipeline that pass is added.
230 static IdentifyingPassPtr overridePass(AnalysisID StandardID,
231                                        IdentifyingPassPtr TargetID) {
232   if (StandardID == &PostRASchedulerID)
233     return applyDisable(TargetID, DisablePostRASched);
234 
235   if (StandardID == &BranchFolderPassID)
236     return applyDisable(TargetID, DisableBranchFold);
237 
238   if (StandardID == &TailDuplicateID)
239     return applyDisable(TargetID, DisableTailDuplicate);
240 
241   if (StandardID == &EarlyTailDuplicateID)
242     return applyDisable(TargetID, DisableEarlyTailDup);
243 
244   if (StandardID == &MachineBlockPlacementID)
245     return applyDisable(TargetID, DisableBlockPlacement);
246 
247   if (StandardID == &StackSlotColoringID)
248     return applyDisable(TargetID, DisableSSC);
249 
250   if (StandardID == &DeadMachineInstructionElimID)
251     return applyDisable(TargetID, DisableMachineDCE);
252 
253   if (StandardID == &EarlyIfConverterID)
254     return applyDisable(TargetID, DisableEarlyIfConversion);
255 
256   if (StandardID == &EarlyMachineLICMID)
257     return applyDisable(TargetID, DisableMachineLICM);
258 
259   if (StandardID == &MachineCSEID)
260     return applyDisable(TargetID, DisableMachineCSE);
261 
262   if (StandardID == &MachineLICMID)
263     return applyDisable(TargetID, DisablePostRAMachineLICM);
264 
265   if (StandardID == &MachineSinkingID)
266     return applyDisable(TargetID, DisableMachineSink);
267 
268   if (StandardID == &PostRAMachineSinkingID)
269     return applyDisable(TargetID, DisablePostRAMachineSink);
270 
271   if (StandardID == &MachineCopyPropagationID)
272     return applyDisable(TargetID, DisableCopyProp);
273 
274   return TargetID;
275 }
276 
277 //===---------------------------------------------------------------------===//
278 /// TargetPassConfig
279 //===---------------------------------------------------------------------===//
280 
281 INITIALIZE_PASS(TargetPassConfig, "targetpassconfig",
282                 "Target Pass Configuration", false, false)
283 char TargetPassConfig::ID = 0;
284 
285 namespace {
286 
287 struct InsertedPass {
288   AnalysisID TargetPassID;
289   IdentifyingPassPtr InsertedPassID;
290   bool VerifyAfter;
291   bool PrintAfter;
292 
293   InsertedPass(AnalysisID TargetPassID, IdentifyingPassPtr InsertedPassID,
294                bool VerifyAfter, bool PrintAfter)
295       : TargetPassID(TargetPassID), InsertedPassID(InsertedPassID),
296         VerifyAfter(VerifyAfter), PrintAfter(PrintAfter) {}
297 
298   Pass *getInsertedPass() const {
299     assert(InsertedPassID.isValid() && "Illegal Pass ID!");
300     if (InsertedPassID.isInstance())
301       return InsertedPassID.getInstance();
302     Pass *NP = Pass::createPass(InsertedPassID.getID());
303     assert(NP && "Pass ID not registered");
304     return NP;
305   }
306 };
307 
308 } // end anonymous namespace
309 
310 namespace llvm {
311 
312 class PassConfigImpl {
313 public:
314   // List of passes explicitly substituted by this target. Normally this is
315   // empty, but it is a convenient way to suppress or replace specific passes
316   // that are part of a standard pass pipeline without overridding the entire
317   // pipeline. This mechanism allows target options to inherit a standard pass's
318   // user interface. For example, a target may disable a standard pass by
319   // default by substituting a pass ID of zero, and the user may still enable
320   // that standard pass with an explicit command line option.
321   DenseMap<AnalysisID,IdentifyingPassPtr> TargetPasses;
322 
323   /// Store the pairs of <AnalysisID, AnalysisID> of which the second pass
324   /// is inserted after each instance of the first one.
325   SmallVector<InsertedPass, 4> InsertedPasses;
326 };
327 
328 } // end namespace llvm
329 
330 // Out of line virtual method.
331 TargetPassConfig::~TargetPassConfig() {
332   delete Impl;
333 }
334 
335 static const PassInfo *getPassInfo(StringRef PassName) {
336   if (PassName.empty())
337     return nullptr;
338 
339   const PassRegistry &PR = *PassRegistry::getPassRegistry();
340   const PassInfo *PI = PR.getPassInfo(PassName);
341   if (!PI)
342     report_fatal_error(Twine('\"') + Twine(PassName) +
343                        Twine("\" pass is not registered."));
344   return PI;
345 }
346 
347 static AnalysisID getPassIDFromName(StringRef PassName) {
348   const PassInfo *PI = getPassInfo(PassName);
349   return PI ? PI->getTypeInfo() : nullptr;
350 }
351 
352 static std::pair<StringRef, unsigned>
353 getPassNameAndInstanceNum(StringRef PassName) {
354   StringRef Name, InstanceNumStr;
355   std::tie(Name, InstanceNumStr) = PassName.split(',');
356 
357   unsigned InstanceNum = 0;
358   if (!InstanceNumStr.empty() && InstanceNumStr.getAsInteger(10, InstanceNum))
359     report_fatal_error("invalid pass instance specifier " + PassName);
360 
361   return std::make_pair(Name, InstanceNum);
362 }
363 
364 void TargetPassConfig::setStartStopPasses() {
365   StringRef StartBeforeName;
366   std::tie(StartBeforeName, StartBeforeInstanceNum) =
367     getPassNameAndInstanceNum(StartBeforeOpt);
368 
369   StringRef StartAfterName;
370   std::tie(StartAfterName, StartAfterInstanceNum) =
371     getPassNameAndInstanceNum(StartAfterOpt);
372 
373   StringRef StopBeforeName;
374   std::tie(StopBeforeName, StopBeforeInstanceNum)
375     = getPassNameAndInstanceNum(StopBeforeOpt);
376 
377   StringRef StopAfterName;
378   std::tie(StopAfterName, StopAfterInstanceNum)
379     = getPassNameAndInstanceNum(StopAfterOpt);
380 
381   StartBefore = getPassIDFromName(StartBeforeName);
382   StartAfter = getPassIDFromName(StartAfterName);
383   StopBefore = getPassIDFromName(StopBeforeName);
384   StopAfter = getPassIDFromName(StopAfterName);
385   if (StartBefore && StartAfter)
386     report_fatal_error(Twine(StartBeforeOptName) + Twine(" and ") +
387                        Twine(StartAfterOptName) + Twine(" specified!"));
388   if (StopBefore && StopAfter)
389     report_fatal_error(Twine(StopBeforeOptName) + Twine(" and ") +
390                        Twine(StopAfterOptName) + Twine(" specified!"));
391   Started = (StartAfter == nullptr) && (StartBefore == nullptr);
392 }
393 
394 // Out of line constructor provides default values for pass options and
395 // registers all common codegen passes.
396 TargetPassConfig::TargetPassConfig(LLVMTargetMachine &TM, PassManagerBase &pm)
397     : ImmutablePass(ID), PM(&pm), TM(&TM) {
398   Impl = new PassConfigImpl();
399 
400   // Register all target independent codegen passes to activate their PassIDs,
401   // including this pass itself.
402   initializeCodeGen(*PassRegistry::getPassRegistry());
403 
404   // Also register alias analysis passes required by codegen passes.
405   initializeBasicAAWrapperPassPass(*PassRegistry::getPassRegistry());
406   initializeAAResultsWrapperPassPass(*PassRegistry::getPassRegistry());
407 
408   if (StringRef(PrintMachineInstrs.getValue()).equals(""))
409     TM.Options.PrintMachineCode = true;
410 
411   if (EnableIPRA.getNumOccurrences())
412     TM.Options.EnableIPRA = EnableIPRA;
413   else {
414     // If not explicitly specified, use target default.
415     TM.Options.EnableIPRA |= TM.useIPRA();
416   }
417 
418   if (TM.Options.EnableIPRA)
419     setRequiresCodeGenSCCOrder();
420 
421   if (EnableGlobalISelAbort.getNumOccurrences())
422     TM.Options.GlobalISelAbort = EnableGlobalISelAbort;
423 
424   setStartStopPasses();
425 }
426 
427 CodeGenOpt::Level TargetPassConfig::getOptLevel() const {
428   return TM->getOptLevel();
429 }
430 
431 /// Insert InsertedPassID pass after TargetPassID.
432 void TargetPassConfig::insertPass(AnalysisID TargetPassID,
433                                   IdentifyingPassPtr InsertedPassID,
434                                   bool VerifyAfter, bool PrintAfter) {
435   assert(((!InsertedPassID.isInstance() &&
436            TargetPassID != InsertedPassID.getID()) ||
437           (InsertedPassID.isInstance() &&
438            TargetPassID != InsertedPassID.getInstance()->getPassID())) &&
439          "Insert a pass after itself!");
440   Impl->InsertedPasses.emplace_back(TargetPassID, InsertedPassID, VerifyAfter,
441                                     PrintAfter);
442 }
443 
444 /// createPassConfig - Create a pass configuration object to be used by
445 /// addPassToEmitX methods for generating a pipeline of CodeGen passes.
446 ///
447 /// Targets may override this to extend TargetPassConfig.
448 TargetPassConfig *LLVMTargetMachine::createPassConfig(PassManagerBase &PM) {
449   return new TargetPassConfig(*this, PM);
450 }
451 
452 TargetPassConfig::TargetPassConfig()
453   : ImmutablePass(ID) {
454   report_fatal_error("Trying to construct TargetPassConfig without a target "
455                      "machine. Scheduling a CodeGen pass without a target "
456                      "triple set?");
457 }
458 
459 bool TargetPassConfig::willCompleteCodeGenPipeline() {
460   return StopBeforeOpt.empty() && StopAfterOpt.empty();
461 }
462 
463 bool TargetPassConfig::hasLimitedCodeGenPipeline() {
464   return !StartBeforeOpt.empty() || !StartAfterOpt.empty() ||
465          !willCompleteCodeGenPipeline();
466 }
467 
468 std::string
469 TargetPassConfig::getLimitedCodeGenPipelineReason(const char *Separator) const {
470   if (!hasLimitedCodeGenPipeline())
471     return std::string();
472   std::string Res;
473   static cl::opt<std::string> *PassNames[] = {&StartAfterOpt, &StartBeforeOpt,
474                                               &StopAfterOpt, &StopBeforeOpt};
475   static const char *OptNames[] = {StartAfterOptName, StartBeforeOptName,
476                                    StopAfterOptName, StopBeforeOptName};
477   bool IsFirst = true;
478   for (int Idx = 0; Idx < 4; ++Idx)
479     if (!PassNames[Idx]->empty()) {
480       if (!IsFirst)
481         Res += Separator;
482       IsFirst = false;
483       Res += OptNames[Idx];
484     }
485   return Res;
486 }
487 
488 // Helper to verify the analysis is really immutable.
489 void TargetPassConfig::setOpt(bool &Opt, bool Val) {
490   assert(!Initialized && "PassConfig is immutable");
491   Opt = Val;
492 }
493 
494 void TargetPassConfig::substitutePass(AnalysisID StandardID,
495                                       IdentifyingPassPtr TargetID) {
496   Impl->TargetPasses[StandardID] = TargetID;
497 }
498 
499 IdentifyingPassPtr TargetPassConfig::getPassSubstitution(AnalysisID ID) const {
500   DenseMap<AnalysisID, IdentifyingPassPtr>::const_iterator
501     I = Impl->TargetPasses.find(ID);
502   if (I == Impl->TargetPasses.end())
503     return ID;
504   return I->second;
505 }
506 
507 bool TargetPassConfig::isPassSubstitutedOrOverridden(AnalysisID ID) const {
508   IdentifyingPassPtr TargetID = getPassSubstitution(ID);
509   IdentifyingPassPtr FinalPtr = overridePass(ID, TargetID);
510   return !FinalPtr.isValid() || FinalPtr.isInstance() ||
511       FinalPtr.getID() != ID;
512 }
513 
514 /// Add a pass to the PassManager if that pass is supposed to be run.  If the
515 /// Started/Stopped flags indicate either that the compilation should start at
516 /// a later pass or that it should stop after an earlier pass, then do not add
517 /// the pass.  Finally, compare the current pass against the StartAfter
518 /// and StopAfter options and change the Started/Stopped flags accordingly.
519 void TargetPassConfig::addPass(Pass *P, bool verifyAfter, bool printAfter) {
520   assert(!Initialized && "PassConfig is immutable");
521 
522   // Cache the Pass ID here in case the pass manager finds this pass is
523   // redundant with ones already scheduled / available, and deletes it.
524   // Fundamentally, once we add the pass to the manager, we no longer own it
525   // and shouldn't reference it.
526   AnalysisID PassID = P->getPassID();
527 
528   if (StartBefore == PassID && StartBeforeCount++ == StartBeforeInstanceNum)
529     Started = true;
530   if (StopBefore == PassID && StopBeforeCount++ == StopBeforeInstanceNum)
531     Stopped = true;
532   if (Started && !Stopped) {
533     if (AddingMachinePasses)
534       addMachinePrePasses();
535     std::string Banner;
536     // Construct banner message before PM->add() as that may delete the pass.
537     if (AddingMachinePasses && (printAfter || verifyAfter))
538       Banner = std::string("After ") + std::string(P->getPassName());
539     PM->add(P);
540     if (AddingMachinePasses)
541       addMachinePostPasses(Banner, /*AllowPrint*/ printAfter,
542                            /*AllowVerify*/ verifyAfter);
543 
544     // Add the passes after the pass P if there is any.
545     for (auto IP : Impl->InsertedPasses) {
546       if (IP.TargetPassID == PassID)
547         addPass(IP.getInsertedPass(), IP.VerifyAfter, IP.PrintAfter);
548     }
549   } else {
550     delete P;
551   }
552 
553   if (StopAfter == PassID && StopAfterCount++ == StopAfterInstanceNum)
554     Stopped = true;
555 
556   if (StartAfter == PassID && StartAfterCount++ == StartAfterInstanceNum)
557     Started = true;
558   if (Stopped && !Started)
559     report_fatal_error("Cannot stop compilation after pass that is not run");
560 }
561 
562 /// Add a CodeGen pass at this point in the pipeline after checking for target
563 /// and command line overrides.
564 ///
565 /// addPass cannot return a pointer to the pass instance because is internal the
566 /// PassManager and the instance we create here may already be freed.
567 AnalysisID TargetPassConfig::addPass(AnalysisID PassID, bool verifyAfter,
568                                      bool printAfter) {
569   IdentifyingPassPtr TargetID = getPassSubstitution(PassID);
570   IdentifyingPassPtr FinalPtr = overridePass(PassID, TargetID);
571   if (!FinalPtr.isValid())
572     return nullptr;
573 
574   Pass *P;
575   if (FinalPtr.isInstance())
576     P = FinalPtr.getInstance();
577   else {
578     P = Pass::createPass(FinalPtr.getID());
579     if (!P)
580       llvm_unreachable("Pass ID not registered");
581   }
582   AnalysisID FinalID = P->getPassID();
583   addPass(P, verifyAfter, printAfter); // Ends the lifetime of P.
584 
585   return FinalID;
586 }
587 
588 void TargetPassConfig::printAndVerify(const std::string &Banner) {
589   addPrintPass(Banner);
590   addVerifyPass(Banner);
591 }
592 
593 void TargetPassConfig::addPrintPass(const std::string &Banner) {
594   if (TM->shouldPrintMachineCode())
595     PM->add(createMachineFunctionPrinterPass(dbgs(), Banner));
596 }
597 
598 void TargetPassConfig::addVerifyPass(const std::string &Banner) {
599   bool Verify = VerifyMachineCode == cl::BOU_TRUE;
600 #ifdef EXPENSIVE_CHECKS
601   if (VerifyMachineCode == cl::BOU_UNSET)
602     Verify = TM->isMachineVerifierClean();
603 #endif
604   if (Verify)
605     PM->add(createMachineVerifierPass(Banner));
606 }
607 
608 void TargetPassConfig::addMachinePrePasses() {}
609 
610 void TargetPassConfig::addMachinePostPasses(const std::string &Banner,
611                                             bool AllowPrint, bool AllowVerify) {
612   if (AllowPrint)
613     addPrintPass(Banner);
614   if (AllowVerify)
615     addVerifyPass(Banner);
616 }
617 
618 /// Add common target configurable passes that perform LLVM IR to IR transforms
619 /// following machine independent optimization.
620 void TargetPassConfig::addIRPasses() {
621   switch (UseCFLAA) {
622   case CFLAAType::Steensgaard:
623     addPass(createCFLSteensAAWrapperPass());
624     break;
625   case CFLAAType::Andersen:
626     addPass(createCFLAndersAAWrapperPass());
627     break;
628   case CFLAAType::Both:
629     addPass(createCFLAndersAAWrapperPass());
630     addPass(createCFLSteensAAWrapperPass());
631     break;
632   default:
633     break;
634   }
635 
636   // Basic AliasAnalysis support.
637   // Add TypeBasedAliasAnalysis before BasicAliasAnalysis so that
638   // BasicAliasAnalysis wins if they disagree. This is intended to help
639   // support "obvious" type-punning idioms.
640   addPass(createTypeBasedAAWrapperPass());
641   addPass(createScopedNoAliasAAWrapperPass());
642   addPass(createBasicAAWrapperPass());
643 
644   // Before running any passes, run the verifier to determine if the input
645   // coming from the front-end and/or optimizer is valid.
646   if (!DisableVerify)
647     addPass(createVerifierPass());
648 
649   // Run loop strength reduction before anything else.
650   if (getOptLevel() != CodeGenOpt::None && !DisableLSR) {
651     addPass(createLoopStrengthReducePass());
652     if (PrintLSR)
653       addPass(createPrintFunctionPass(dbgs(), "\n\n*** Code after LSR ***\n"));
654   }
655 
656   if (getOptLevel() != CodeGenOpt::None) {
657     // The MergeICmpsPass tries to create memcmp calls by grouping sequences of
658     // loads and compares. ExpandMemCmpPass then tries to expand those calls
659     // into optimally-sized loads and compares. The transforms are enabled by a
660     // target lowering hook.
661     if (!DisableMergeICmps)
662       addPass(createMergeICmpsLegacyPass());
663     addPass(createExpandMemCmpPass());
664   }
665 
666   // Run GC lowering passes for builtin collectors
667   // TODO: add a pass insertion point here
668   addPass(createGCLoweringPass());
669   addPass(createShadowStackGCLoweringPass());
670   addPass(createLowerConstantIntrinsicsPass());
671 
672   // Make sure that no unreachable blocks are instruction selected.
673   addPass(createUnreachableBlockEliminationPass());
674 
675   // Prepare expensive constants for SelectionDAG.
676   if (getOptLevel() != CodeGenOpt::None && !DisableConstantHoisting)
677     addPass(createConstantHoistingPass());
678 
679   if (getOptLevel() != CodeGenOpt::None && !DisablePartialLibcallInlining)
680     addPass(createPartiallyInlineLibCallsPass());
681 
682   // Instrument function entry and exit, e.g. with calls to mcount().
683   addPass(createPostInlineEntryExitInstrumenterPass());
684 
685   // Add scalarization of target's unsupported masked memory intrinsics pass.
686   // the unsupported intrinsic will be replaced with a chain of basic blocks,
687   // that stores/loads element one-by-one if the appropriate mask bit is set.
688   addPass(createScalarizeMaskedMemIntrinPass());
689 
690   // Expand reduction intrinsics into shuffle sequences if the target wants to.
691   addPass(createExpandReductionsPass());
692 }
693 
694 /// Turn exception handling constructs into something the code generators can
695 /// handle.
696 void TargetPassConfig::addPassesToHandleExceptions() {
697   const MCAsmInfo *MCAI = TM->getMCAsmInfo();
698   assert(MCAI && "No MCAsmInfo");
699   switch (MCAI->getExceptionHandlingType()) {
700   case ExceptionHandling::SjLj:
701     // SjLj piggy-backs on dwarf for this bit. The cleanups done apply to both
702     // Dwarf EH prepare needs to be run after SjLj prepare. Otherwise,
703     // catch info can get misplaced when a selector ends up more than one block
704     // removed from the parent invoke(s). This could happen when a landing
705     // pad is shared by multiple invokes and is also a target of a normal
706     // edge from elsewhere.
707     addPass(createSjLjEHPreparePass(TM));
708     LLVM_FALLTHROUGH;
709   case ExceptionHandling::DwarfCFI:
710   case ExceptionHandling::ARM:
711     addPass(createDwarfEHPass());
712     break;
713   case ExceptionHandling::WinEH:
714     // We support using both GCC-style and MSVC-style exceptions on Windows, so
715     // add both preparation passes. Each pass will only actually run if it
716     // recognizes the personality function.
717     addPass(createWinEHPass());
718     addPass(createDwarfEHPass());
719     break;
720   case ExceptionHandling::Wasm:
721     // Wasm EH uses Windows EH instructions, but it does not need to demote PHIs
722     // on catchpads and cleanuppads because it does not outline them into
723     // funclets. Catchswitch blocks are not lowered in SelectionDAG, so we
724     // should remove PHIs there.
725     addPass(createWinEHPass(/*DemoteCatchSwitchPHIOnly=*/false));
726     addPass(createWasmEHPass());
727     break;
728   case ExceptionHandling::None:
729     addPass(createLowerInvokePass());
730 
731     // The lower invoke pass may create unreachable code. Remove it.
732     addPass(createUnreachableBlockEliminationPass());
733     break;
734   }
735 }
736 
737 /// Add pass to prepare the LLVM IR for code generation. This should be done
738 /// before exception handling preparation passes.
739 void TargetPassConfig::addCodeGenPrepare() {
740   if (getOptLevel() != CodeGenOpt::None && !DisableCGP)
741     addPass(createCodeGenPreparePass());
742   addPass(createRewriteSymbolsPass());
743 }
744 
745 /// Add common passes that perform LLVM IR to IR transforms in preparation for
746 /// instruction selection.
747 void TargetPassConfig::addISelPrepare() {
748   addPreISel();
749 
750   // Force codegen to run according to the callgraph.
751   if (requiresCodeGenSCCOrder())
752     addPass(new DummyCGSCCPass);
753 
754   // Add both the safe stack and the stack protection passes: each of them will
755   // only protect functions that have corresponding attributes.
756   addPass(createSafeStackPass());
757   addPass(createStackProtectorPass());
758 
759   if (PrintISelInput)
760     addPass(createPrintFunctionPass(
761         dbgs(), "\n\n*** Final LLVM Code input to ISel ***\n"));
762 
763   // All passes which modify the LLVM IR are now complete; run the verifier
764   // to ensure that the IR is valid.
765   if (!DisableVerify)
766     addPass(createVerifierPass());
767 }
768 
769 bool TargetPassConfig::addCoreISelPasses() {
770   // Enable FastISel with -fast-isel, but allow that to be overridden.
771   TM->setO0WantsFastISel(EnableFastISelOption != cl::BOU_FALSE);
772 
773   // Determine an instruction selector.
774   enum class SelectorType { SelectionDAG, FastISel, GlobalISel };
775   SelectorType Selector;
776 
777   if (EnableFastISelOption == cl::BOU_TRUE)
778     Selector = SelectorType::FastISel;
779   else if (EnableGlobalISelOption == cl::BOU_TRUE ||
780            (TM->Options.EnableGlobalISel &&
781             EnableGlobalISelOption != cl::BOU_FALSE))
782     Selector = SelectorType::GlobalISel;
783   else if (TM->getOptLevel() == CodeGenOpt::None && TM->getO0WantsFastISel())
784     Selector = SelectorType::FastISel;
785   else
786     Selector = SelectorType::SelectionDAG;
787 
788   // Set consistently TM->Options.EnableFastISel and EnableGlobalISel.
789   if (Selector == SelectorType::FastISel) {
790     TM->setFastISel(true);
791     TM->setGlobalISel(false);
792   } else if (Selector == SelectorType::GlobalISel) {
793     TM->setFastISel(false);
794     TM->setGlobalISel(true);
795   }
796 
797   // Add instruction selector passes.
798   if (Selector == SelectorType::GlobalISel) {
799     SaveAndRestore<bool> SavedAddingMachinePasses(AddingMachinePasses, true);
800     if (addIRTranslator())
801       return true;
802 
803     addPreLegalizeMachineIR();
804 
805     if (addLegalizeMachineIR())
806       return true;
807 
808     // Before running the register bank selector, ask the target if it
809     // wants to run some passes.
810     addPreRegBankSelect();
811 
812     if (addRegBankSelect())
813       return true;
814 
815     addPreGlobalInstructionSelect();
816 
817     if (addGlobalInstructionSelect())
818       return true;
819 
820     // Pass to reset the MachineFunction if the ISel failed.
821     addPass(createResetMachineFunctionPass(
822         reportDiagnosticWhenGlobalISelFallback(), isGlobalISelAbortEnabled()));
823 
824     // Provide a fallback path when we do not want to abort on
825     // not-yet-supported input.
826     if (!isGlobalISelAbortEnabled() && addInstSelector())
827       return true;
828 
829   } else if (addInstSelector())
830     return true;
831 
832   // Expand pseudo-instructions emitted by ISel. Don't run the verifier before
833   // FinalizeISel.
834   addPass(&FinalizeISelID);
835 
836   // Print the instruction selected machine code...
837   printAndVerify("After Instruction Selection");
838 
839   return false;
840 }
841 
842 bool TargetPassConfig::addISelPasses() {
843   if (TM->useEmulatedTLS())
844     addPass(createLowerEmuTLSPass());
845 
846   addPass(createPreISelIntrinsicLoweringPass());
847   addPass(createTargetTransformInfoWrapperPass(TM->getTargetIRAnalysis()));
848   addIRPasses();
849   addCodeGenPrepare();
850   addPassesToHandleExceptions();
851   addISelPrepare();
852 
853   return addCoreISelPasses();
854 }
855 
856 /// -regalloc=... command line option.
857 static FunctionPass *useDefaultRegisterAllocator() { return nullptr; }
858 static cl::opt<RegisterRegAlloc::FunctionPassCtor, false,
859                RegisterPassParser<RegisterRegAlloc>>
860     RegAlloc("regalloc", cl::Hidden, cl::init(&useDefaultRegisterAllocator),
861              cl::desc("Register allocator to use"));
862 
863 /// Add the complete set of target-independent postISel code generator passes.
864 ///
865 /// This can be read as the standard order of major LLVM CodeGen stages. Stages
866 /// with nontrivial configuration or multiple passes are broken out below in
867 /// add%Stage routines.
868 ///
869 /// Any TargetPassConfig::addXX routine may be overriden by the Target. The
870 /// addPre/Post methods with empty header implementations allow injecting
871 /// target-specific fixups just before or after major stages. Additionally,
872 /// targets have the flexibility to change pass order within a stage by
873 /// overriding default implementation of add%Stage routines below. Each
874 /// technique has maintainability tradeoffs because alternate pass orders are
875 /// not well supported. addPre/Post works better if the target pass is easily
876 /// tied to a common pass. But if it has subtle dependencies on multiple passes,
877 /// the target should override the stage instead.
878 ///
879 /// TODO: We could use a single addPre/Post(ID) hook to allow pass injection
880 /// before/after any target-independent pass. But it's currently overkill.
881 void TargetPassConfig::addMachinePasses() {
882   AddingMachinePasses = true;
883 
884   // Insert a machine instr printer pass after the specified pass.
885   StringRef PrintMachineInstrsPassName = PrintMachineInstrs.getValue();
886   if (!PrintMachineInstrsPassName.equals("") &&
887       !PrintMachineInstrsPassName.equals("option-unspecified")) {
888     if (const PassInfo *TPI = getPassInfo(PrintMachineInstrsPassName)) {
889       const PassRegistry *PR = PassRegistry::getPassRegistry();
890       const PassInfo *IPI = PR->getPassInfo(StringRef("machineinstr-printer"));
891       assert(IPI && "failed to get \"machineinstr-printer\" PassInfo!");
892       const char *TID = (const char *)(TPI->getTypeInfo());
893       const char *IID = (const char *)(IPI->getTypeInfo());
894       insertPass(TID, IID);
895     }
896   }
897 
898   // Add passes that optimize machine instructions in SSA form.
899   if (getOptLevel() != CodeGenOpt::None) {
900     addMachineSSAOptimization();
901   } else {
902     // If the target requests it, assign local variables to stack slots relative
903     // to one another and simplify frame index references where possible.
904     addPass(&LocalStackSlotAllocationID, false);
905   }
906 
907   if (TM->Options.EnableIPRA)
908     addPass(createRegUsageInfoPropPass());
909 
910   // Run pre-ra passes.
911   addPreRegAlloc();
912 
913   // Run register allocation and passes that are tightly coupled with it,
914   // including phi elimination and scheduling.
915   if (getOptimizeRegAlloc())
916     addOptimizedRegAlloc();
917   else
918     addFastRegAlloc();
919 
920   // Run post-ra passes.
921   addPostRegAlloc();
922 
923   addPass(&FixupStatepointCallerSavedID);
924 
925   // Insert prolog/epilog code.  Eliminate abstract frame index references...
926   if (getOptLevel() != CodeGenOpt::None) {
927     addPass(&PostRAMachineSinkingID);
928     addPass(&ShrinkWrapID);
929   }
930 
931   // Prolog/Epilog inserter needs a TargetMachine to instantiate. But only
932   // do so if it hasn't been disabled, substituted, or overridden.
933   if (!isPassSubstitutedOrOverridden(&PrologEpilogCodeInserterID))
934       addPass(createPrologEpilogInserterPass());
935 
936   /// Add passes that optimize machine instructions after register allocation.
937   if (getOptLevel() != CodeGenOpt::None)
938     addMachineLateOptimization();
939 
940   // Expand pseudo instructions before second scheduling pass.
941   addPass(&ExpandPostRAPseudosID);
942 
943   // Run pre-sched2 passes.
944   addPreSched2();
945 
946   if (EnableImplicitNullChecks)
947     addPass(&ImplicitNullChecksID);
948 
949   // Second pass scheduler.
950   // Let Target optionally insert this pass by itself at some other
951   // point.
952   if (getOptLevel() != CodeGenOpt::None &&
953       !TM->targetSchedulesPostRAScheduling()) {
954     if (MISchedPostRA)
955       addPass(&PostMachineSchedulerID);
956     else
957       addPass(&PostRASchedulerID);
958   }
959 
960   // GC
961   if (addGCPasses()) {
962     if (PrintGCInfo)
963       addPass(createGCInfoPrinter(dbgs()), false, false);
964   }
965 
966   // Basic block placement.
967   if (getOptLevel() != CodeGenOpt::None)
968     addBlockPlacement();
969 
970   // Insert before XRay Instrumentation.
971   addPass(&FEntryInserterID, false);
972 
973   addPass(&XRayInstrumentationID, false);
974   addPass(&PatchableFunctionID, false);
975 
976   addPreEmitPass();
977 
978   if (TM->Options.EnableIPRA)
979     // Collect register usage information and produce a register mask of
980     // clobbered registers, to be used to optimize call sites.
981     addPass(createRegUsageInfoCollector());
982 
983   addPass(&FuncletLayoutID, false);
984 
985   addPass(&StackMapLivenessID, false);
986   addPass(&LiveDebugValuesID, false);
987 
988   if (TM->Options.EnableMachineOutliner && getOptLevel() != CodeGenOpt::None &&
989       EnableMachineOutliner != NeverOutline) {
990     bool RunOnAllFunctions = (EnableMachineOutliner == AlwaysOutline);
991     bool AddOutliner = RunOnAllFunctions ||
992                        TM->Options.SupportsDefaultOutlining;
993     if (AddOutliner)
994       addPass(createMachineOutlinerPass(RunOnAllFunctions));
995   }
996 
997   if (TM->getBBSectionsType() != llvm::BasicBlockSection::None)
998     addPass(llvm::createBBSectionsPreparePass(TM->getBBSectionsFuncListBuf()));
999 
1000   // Add passes that directly emit MI after all other MI passes.
1001   addPreEmitPass2();
1002 
1003   AddingMachinePasses = false;
1004 }
1005 
1006 /// Add passes that optimize machine instructions in SSA form.
1007 void TargetPassConfig::addMachineSSAOptimization() {
1008   // Pre-ra tail duplication.
1009   addPass(&EarlyTailDuplicateID);
1010 
1011   // Optimize PHIs before DCE: removing dead PHI cycles may make more
1012   // instructions dead.
1013   addPass(&OptimizePHIsID, false);
1014 
1015   // This pass merges large allocas. StackSlotColoring is a different pass
1016   // which merges spill slots.
1017   addPass(&StackColoringID, false);
1018 
1019   // If the target requests it, assign local variables to stack slots relative
1020   // to one another and simplify frame index references where possible.
1021   addPass(&LocalStackSlotAllocationID, false);
1022 
1023   // With optimization, dead code should already be eliminated. However
1024   // there is one known exception: lowered code for arguments that are only
1025   // used by tail calls, where the tail calls reuse the incoming stack
1026   // arguments directly (see t11 in test/CodeGen/X86/sibcall.ll).
1027   addPass(&DeadMachineInstructionElimID);
1028 
1029   // Allow targets to insert passes that improve instruction level parallelism,
1030   // like if-conversion. Such passes will typically need dominator trees and
1031   // loop info, just like LICM and CSE below.
1032   addILPOpts();
1033 
1034   addPass(&EarlyMachineLICMID, false);
1035   addPass(&MachineCSEID, false);
1036 
1037   addPass(&MachineSinkingID);
1038 
1039   addPass(&PeepholeOptimizerID);
1040   // Clean-up the dead code that may have been generated by peephole
1041   // rewriting.
1042   addPass(&DeadMachineInstructionElimID);
1043 }
1044 
1045 //===---------------------------------------------------------------------===//
1046 /// Register Allocation Pass Configuration
1047 //===---------------------------------------------------------------------===//
1048 
1049 bool TargetPassConfig::getOptimizeRegAlloc() const {
1050   switch (OptimizeRegAlloc) {
1051   case cl::BOU_UNSET: return getOptLevel() != CodeGenOpt::None;
1052   case cl::BOU_TRUE:  return true;
1053   case cl::BOU_FALSE: return false;
1054   }
1055   llvm_unreachable("Invalid optimize-regalloc state");
1056 }
1057 
1058 /// A dummy default pass factory indicates whether the register allocator is
1059 /// overridden on the command line.
1060 static llvm::once_flag InitializeDefaultRegisterAllocatorFlag;
1061 
1062 static RegisterRegAlloc
1063 defaultRegAlloc("default",
1064                 "pick register allocator based on -O option",
1065                 useDefaultRegisterAllocator);
1066 
1067 static void initializeDefaultRegisterAllocatorOnce() {
1068   if (!RegisterRegAlloc::getDefault())
1069     RegisterRegAlloc::setDefault(RegAlloc);
1070 }
1071 
1072 /// Instantiate the default register allocator pass for this target for either
1073 /// the optimized or unoptimized allocation path. This will be added to the pass
1074 /// manager by addFastRegAlloc in the unoptimized case or addOptimizedRegAlloc
1075 /// in the optimized case.
1076 ///
1077 /// A target that uses the standard regalloc pass order for fast or optimized
1078 /// allocation may still override this for per-target regalloc
1079 /// selection. But -regalloc=... always takes precedence.
1080 FunctionPass *TargetPassConfig::createTargetRegisterAllocator(bool Optimized) {
1081   if (Optimized)
1082     return createGreedyRegisterAllocator();
1083   else
1084     return createFastRegisterAllocator();
1085 }
1086 
1087 /// Find and instantiate the register allocation pass requested by this target
1088 /// at the current optimization level.  Different register allocators are
1089 /// defined as separate passes because they may require different analysis.
1090 ///
1091 /// This helper ensures that the regalloc= option is always available,
1092 /// even for targets that override the default allocator.
1093 ///
1094 /// FIXME: When MachinePassRegistry register pass IDs instead of function ptrs,
1095 /// this can be folded into addPass.
1096 FunctionPass *TargetPassConfig::createRegAllocPass(bool Optimized) {
1097   // Initialize the global default.
1098   llvm::call_once(InitializeDefaultRegisterAllocatorFlag,
1099                   initializeDefaultRegisterAllocatorOnce);
1100 
1101   RegisterRegAlloc::FunctionPassCtor Ctor = RegisterRegAlloc::getDefault();
1102   if (Ctor != useDefaultRegisterAllocator)
1103     return Ctor();
1104 
1105   // With no -regalloc= override, ask the target for a regalloc pass.
1106   return createTargetRegisterAllocator(Optimized);
1107 }
1108 
1109 bool TargetPassConfig::addRegAssignmentFast() {
1110   if (RegAlloc != &useDefaultRegisterAllocator &&
1111       RegAlloc != &createFastRegisterAllocator)
1112     report_fatal_error("Must use fast (default) register allocator for unoptimized regalloc.");
1113 
1114   addPass(createRegAllocPass(false));
1115   return true;
1116 }
1117 
1118 bool TargetPassConfig::addRegAssignmentOptimized() {
1119   // Add the selected register allocation pass.
1120   addPass(createRegAllocPass(true));
1121 
1122   // Allow targets to change the register assignments before rewriting.
1123   addPreRewrite();
1124 
1125   // Finally rewrite virtual registers.
1126   addPass(&VirtRegRewriterID);
1127   // Perform stack slot coloring and post-ra machine LICM.
1128   //
1129   // FIXME: Re-enable coloring with register when it's capable of adding
1130   // kill markers.
1131   addPass(&StackSlotColoringID);
1132 
1133   return true;
1134 }
1135 
1136 /// Return true if the default global register allocator is in use and
1137 /// has not be overriden on the command line with '-regalloc=...'
1138 bool TargetPassConfig::usingDefaultRegAlloc() const {
1139   return RegAlloc.getNumOccurrences() == 0;
1140 }
1141 
1142 /// Add the minimum set of target-independent passes that are required for
1143 /// register allocation. No coalescing or scheduling.
1144 void TargetPassConfig::addFastRegAlloc() {
1145   addPass(&PHIEliminationID, false);
1146   addPass(&TwoAddressInstructionPassID, false);
1147 
1148   addRegAssignmentFast();
1149 }
1150 
1151 /// Add standard target-independent passes that are tightly coupled with
1152 /// optimized register allocation, including coalescing, machine instruction
1153 /// scheduling, and register allocation itself.
1154 void TargetPassConfig::addOptimizedRegAlloc() {
1155   addPass(&DetectDeadLanesID, false);
1156 
1157   addPass(&ProcessImplicitDefsID, false);
1158 
1159   // LiveVariables currently requires pure SSA form.
1160   //
1161   // FIXME: Once TwoAddressInstruction pass no longer uses kill flags,
1162   // LiveVariables can be removed completely, and LiveIntervals can be directly
1163   // computed. (We still either need to regenerate kill flags after regalloc, or
1164   // preferably fix the scavenger to not depend on them).
1165   addPass(&LiveVariablesID, false);
1166 
1167   // Edge splitting is smarter with machine loop info.
1168   addPass(&MachineLoopInfoID, false);
1169   addPass(&PHIEliminationID, false);
1170 
1171   // Eventually, we want to run LiveIntervals before PHI elimination.
1172   if (EarlyLiveIntervals)
1173     addPass(&LiveIntervalsID, false);
1174 
1175   addPass(&TwoAddressInstructionPassID, false);
1176   addPass(&RegisterCoalescerID);
1177 
1178   // The machine scheduler may accidentally create disconnected components
1179   // when moving subregister definitions around, avoid this by splitting them to
1180   // separate vregs before. Splitting can also improve reg. allocation quality.
1181   addPass(&RenameIndependentSubregsID);
1182 
1183   // PreRA instruction scheduling.
1184   addPass(&MachineSchedulerID);
1185 
1186   if (addRegAssignmentOptimized()) {
1187     // Allow targets to expand pseudo instructions depending on the choice of
1188     // registers before MachineCopyPropagation.
1189     addPostRewrite();
1190 
1191     // Copy propagate to forward register uses and try to eliminate COPYs that
1192     // were not coalesced.
1193     addPass(&MachineCopyPropagationID);
1194 
1195     // Run post-ra machine LICM to hoist reloads / remats.
1196     //
1197     // FIXME: can this move into MachineLateOptimization?
1198     addPass(&MachineLICMID);
1199   }
1200 }
1201 
1202 //===---------------------------------------------------------------------===//
1203 /// Post RegAlloc Pass Configuration
1204 //===---------------------------------------------------------------------===//
1205 
1206 /// Add passes that optimize machine instructions after register allocation.
1207 void TargetPassConfig::addMachineLateOptimization() {
1208   // Branch folding must be run after regalloc and prolog/epilog insertion.
1209   addPass(&BranchFolderPassID);
1210 
1211   // Tail duplication.
1212   // Note that duplicating tail just increases code size and degrades
1213   // performance for targets that require Structured Control Flow.
1214   // In addition it can also make CFG irreducible. Thus we disable it.
1215   if (!TM->requiresStructuredCFG())
1216     addPass(&TailDuplicateID);
1217 
1218   // Copy propagation.
1219   addPass(&MachineCopyPropagationID);
1220 }
1221 
1222 /// Add standard GC passes.
1223 bool TargetPassConfig::addGCPasses() {
1224   addPass(&GCMachineCodeAnalysisID, false);
1225   return true;
1226 }
1227 
1228 /// Add standard basic block placement passes.
1229 void TargetPassConfig::addBlockPlacement() {
1230   if (addPass(&MachineBlockPlacementID)) {
1231     // Run a separate pass to collect block placement statistics.
1232     if (EnableBlockPlacementStats)
1233       addPass(&MachineBlockPlacementStatsID);
1234   }
1235 }
1236 
1237 //===---------------------------------------------------------------------===//
1238 /// GlobalISel Configuration
1239 //===---------------------------------------------------------------------===//
1240 bool TargetPassConfig::isGlobalISelAbortEnabled() const {
1241   return TM->Options.GlobalISelAbort == GlobalISelAbortMode::Enable;
1242 }
1243 
1244 bool TargetPassConfig::reportDiagnosticWhenGlobalISelFallback() const {
1245   return TM->Options.GlobalISelAbort == GlobalISelAbortMode::DisableWithDiag;
1246 }
1247 
1248 bool TargetPassConfig::isGISelCSEEnabled() const {
1249   return true;
1250 }
1251 
1252 std::unique_ptr<CSEConfigBase> TargetPassConfig::getCSEConfig() const {
1253   return std::make_unique<CSEConfigBase>();
1254 }
1255