1 //===-- Passes.cpp - Target independent code generation passes ------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defines interfaces to access the target independent code
11 // generation passes provided by the LLVM backend.
13 //===---------------------------------------------------------------------===//
15 #include "llvm/Analysis/Passes.h"
16 #include "llvm/Analysis/Verifier.h"
17 #include "llvm/Transforms/Scalar.h"
18 #include "llvm/PassManager.h"
19 #include "llvm/CodeGen/GCStrategy.h"
20 #include "llvm/CodeGen/MachineFunctionPass.h"
21 #include "llvm/CodeGen/Passes.h"
22 #include "llvm/CodeGen/RegAllocRegistry.h"
23 #include "llvm/Target/TargetLowering.h"
24 #include "llvm/Target/TargetOptions.h"
25 #include "llvm/MC/MCAsmInfo.h"
26 #include "llvm/Assembly/PrintModulePass.h"
27 #include "llvm/Support/CommandLine.h"
28 #include "llvm/Support/Debug.h"
29 #include "llvm/Support/ErrorHandling.h"
33 static cl::opt<bool> DisablePostRA("disable-post-ra", cl::Hidden,
34 cl::desc("Disable Post Regalloc"));
35 static cl::opt<bool> DisableBranchFold("disable-branch-fold", cl::Hidden,
36 cl::desc("Disable branch folding"));
37 static cl::opt<bool> DisableTailDuplicate("disable-tail-duplicate", cl::Hidden,
38 cl::desc("Disable tail duplication"));
39 static cl::opt<bool> DisableEarlyTailDup("disable-early-taildup", cl::Hidden,
40 cl::desc("Disable pre-register allocation tail duplication"));
41 static cl::opt<bool> DisableBlockPlacement("disable-block-placement",
42 cl::Hidden, cl::desc("Disable the probability-driven block placement, and "
43 "re-enable the old code placement pass"));
44 static cl::opt<bool> EnableBlockPlacementStats("enable-block-placement-stats",
45 cl::Hidden, cl::desc("Collect probability-driven block placement stats"));
46 static cl::opt<bool> DisableCodePlace("disable-code-place", cl::Hidden,
47 cl::desc("Disable code placement"));
48 static cl::opt<bool> DisableSSC("disable-ssc", cl::Hidden,
49 cl::desc("Disable Stack Slot Coloring"));
50 static cl::opt<bool> DisableMachineDCE("disable-machine-dce", cl::Hidden,
51 cl::desc("Disable Machine Dead Code Elimination"));
52 static cl::opt<bool> EnableEarlyIfConversion("enable-early-ifcvt", cl::Hidden,
53 cl::desc("Enable Early If-conversion"));
54 static cl::opt<bool> DisableMachineLICM("disable-machine-licm", cl::Hidden,
55 cl::desc("Disable Machine LICM"));
56 static cl::opt<bool> DisableMachineCSE("disable-machine-cse", cl::Hidden,
57 cl::desc("Disable Machine Common Subexpression Elimination"));
58 static cl::opt<cl::boolOrDefault>
59 OptimizeRegAlloc("optimize-regalloc", cl::Hidden,
60 cl::desc("Enable optimized register allocation compilation path."));
61 static cl::opt<cl::boolOrDefault>
62 EnableMachineSched("enable-misched", cl::Hidden,
63 cl::desc("Enable the machine instruction scheduling pass."));
64 static cl::opt<bool> EnableStrongPHIElim("strong-phi-elim", cl::Hidden,
65 cl::desc("Use strong PHI elimination."));
66 static cl::opt<bool> DisablePostRAMachineLICM("disable-postra-machine-licm",
68 cl::desc("Disable Machine LICM"));
69 static cl::opt<bool> DisableMachineSink("disable-machine-sink", cl::Hidden,
70 cl::desc("Disable Machine Sinking"));
71 static cl::opt<bool> DisableLSR("disable-lsr", cl::Hidden,
72 cl::desc("Disable Loop Strength Reduction Pass"));
73 static cl::opt<bool> DisableCGP("disable-cgp", cl::Hidden,
74 cl::desc("Disable Codegen Prepare"));
75 static cl::opt<bool> DisableCopyProp("disable-copyprop", cl::Hidden,
76 cl::desc("Disable Copy Propagation pass"));
77 static cl::opt<bool> PrintLSR("print-lsr-output", cl::Hidden,
78 cl::desc("Print LLVM IR produced by the loop-reduce pass"));
79 static cl::opt<bool> PrintISelInput("print-isel-input", cl::Hidden,
80 cl::desc("Print LLVM IR input to isel pass"));
81 static cl::opt<bool> PrintGCInfo("print-gc", cl::Hidden,
82 cl::desc("Dump garbage collector data"));
83 static cl::opt<bool> VerifyMachineCode("verify-machineinstrs", cl::Hidden,
84 cl::desc("Verify generated machine code"),
85 cl::init(getenv("LLVM_VERIFY_MACHINEINSTRS")!=NULL));
86 static cl::opt<std::string>
87 PrintMachineInstrs("print-machineinstrs", cl::ValueOptional,
88 cl::desc("Print machine instrs"),
89 cl::value_desc("pass-name"), cl::init("option-unspecified"));
91 // Experimental option to run live inteerval analysis early.
92 static cl::opt<bool> EarlyLiveIntervals("early-live-intervals", cl::Hidden,
93 cl::desc("Run live interval analysis earlier in the pipeline"));
95 /// Allow standard passes to be disabled by command line options. This supports
96 /// simple binary flags that either suppress the pass or do nothing.
97 /// i.e. -disable-mypass=false has no effect.
98 /// These should be converted to boolOrDefault in order to use applyOverride.
99 static AnalysisID applyDisable(AnalysisID PassID, bool Override) {
105 /// Allow Pass selection to be overriden by command line options. This supports
106 /// flags with ternary conditions. TargetID is passed through by default. The
107 /// pass is suppressed when the option is false. When the option is true, the
108 /// StandardID is selected if the target provides no default.
109 static AnalysisID applyOverride(AnalysisID TargetID, cl::boolOrDefault Override,
110 AnalysisID StandardID) {
118 report_fatal_error("Target cannot enable pass");
123 llvm_unreachable("Invalid command line option state");
126 /// Allow standard passes to be disabled by the command line, regardless of who
127 /// is adding the pass.
129 /// StandardID is the pass identified in the standard pass pipeline and provided
130 /// to addPass(). It may be a target-specific ID in the case that the target
131 /// directly adds its own pass, but in that case we harmlessly fall through.
133 /// TargetID is the pass that the target has configured to override StandardID.
135 /// StandardID may be a pseudo ID. In that case TargetID is the name of the real
136 /// pass to run. This allows multiple options to control a single pass depending
137 /// on where in the pipeline that pass is added.
138 static AnalysisID overridePass(AnalysisID StandardID, AnalysisID TargetID) {
139 if (StandardID == &PostRASchedulerID)
140 return applyDisable(TargetID, DisablePostRA);
142 if (StandardID == &BranchFolderPassID)
143 return applyDisable(TargetID, DisableBranchFold);
145 if (StandardID == &TailDuplicateID)
146 return applyDisable(TargetID, DisableTailDuplicate);
148 if (StandardID == &TargetPassConfig::EarlyTailDuplicateID)
149 return applyDisable(TargetID, DisableEarlyTailDup);
151 if (StandardID == &MachineBlockPlacementID)
152 return applyDisable(TargetID, DisableCodePlace);
154 if (StandardID == &CodePlacementOptID)
155 return applyDisable(TargetID, DisableCodePlace);
157 if (StandardID == &StackSlotColoringID)
158 return applyDisable(TargetID, DisableSSC);
160 if (StandardID == &DeadMachineInstructionElimID)
161 return applyDisable(TargetID, DisableMachineDCE);
163 if (StandardID == &EarlyIfConverterID)
164 return applyDisable(TargetID, !EnableEarlyIfConversion);
166 if (StandardID == &MachineLICMID)
167 return applyDisable(TargetID, DisableMachineLICM);
169 if (StandardID == &MachineCSEID)
170 return applyDisable(TargetID, DisableMachineCSE);
172 if (StandardID == &MachineSchedulerID)
173 return applyOverride(TargetID, EnableMachineSched, StandardID);
175 if (StandardID == &TargetPassConfig::PostRAMachineLICMID)
176 return applyDisable(TargetID, DisablePostRAMachineLICM);
178 if (StandardID == &MachineSinkingID)
179 return applyDisable(TargetID, DisableMachineSink);
181 if (StandardID == &MachineCopyPropagationID)
182 return applyDisable(TargetID, DisableCopyProp);
187 //===---------------------------------------------------------------------===//
189 //===---------------------------------------------------------------------===//
191 INITIALIZE_PASS(TargetPassConfig, "targetpassconfig",
192 "Target Pass Configuration", false, false)
193 char TargetPassConfig::ID = 0;
196 char TargetPassConfig::EarlyTailDuplicateID = 0;
197 char TargetPassConfig::PostRAMachineLICMID = 0;
200 class PassConfigImpl {
202 // List of passes explicitly substituted by this target. Normally this is
203 // empty, but it is a convenient way to suppress or replace specific passes
204 // that are part of a standard pass pipeline without overridding the entire
205 // pipeline. This mechanism allows target options to inherit a standard pass's
206 // user interface. For example, a target may disable a standard pass by
207 // default by substituting a pass ID of zero, and the user may still enable
208 // that standard pass with an explicit command line option.
209 DenseMap<AnalysisID,AnalysisID> TargetPasses;
211 /// Store the pairs of <AnalysisID, AnalysisID> of which the second pass
212 /// is inserted after each instance of the first one.
213 SmallVector<std::pair<AnalysisID, AnalysisID>, 4> InsertedPasses;
217 // Out of line virtual method.
218 TargetPassConfig::~TargetPassConfig() {
222 // Out of line constructor provides default values for pass options and
223 // registers all common codegen passes.
224 TargetPassConfig::TargetPassConfig(TargetMachine *tm, PassManagerBase &pm)
225 : ImmutablePass(ID), PM(&pm), StartAfter(0), StopAfter(0),
226 Started(true), Stopped(false), TM(tm), Impl(0), Initialized(false),
227 DisableVerify(false),
228 EnableTailMerge(true) {
230 Impl = new PassConfigImpl();
232 // Register all target independent codegen passes to activate their PassIDs,
233 // including this pass itself.
234 initializeCodeGen(*PassRegistry::getPassRegistry());
236 // Substitute Pseudo Pass IDs for real ones.
237 substitutePass(&EarlyTailDuplicateID, &TailDuplicateID);
238 substitutePass(&PostRAMachineLICMID, &MachineLICMID);
240 // Disable early if-conversion. Targets that are ready can enable it.
241 disablePass(&EarlyIfConverterID);
243 // Temporarily disable experimental passes.
244 substitutePass(&MachineSchedulerID, 0);
247 /// Insert InsertedPassID pass after TargetPassID.
248 void TargetPassConfig::insertPass(AnalysisID TargetPassID,
249 AnalysisID InsertedPassID) {
250 assert(TargetPassID != InsertedPassID && "Insert a pass after itself!");
251 std::pair<AnalysisID, AnalysisID> P(TargetPassID, InsertedPassID);
252 Impl->InsertedPasses.push_back(P);
255 /// createPassConfig - Create a pass configuration object to be used by
256 /// addPassToEmitX methods for generating a pipeline of CodeGen passes.
258 /// Targets may override this to extend TargetPassConfig.
259 TargetPassConfig *LLVMTargetMachine::createPassConfig(PassManagerBase &PM) {
260 return new TargetPassConfig(this, PM);
263 TargetPassConfig::TargetPassConfig()
264 : ImmutablePass(ID), PM(0) {
265 llvm_unreachable("TargetPassConfig should not be constructed on-the-fly");
268 // Helper to verify the analysis is really immutable.
269 void TargetPassConfig::setOpt(bool &Opt, bool Val) {
270 assert(!Initialized && "PassConfig is immutable");
274 void TargetPassConfig::substitutePass(AnalysisID StandardID,
275 AnalysisID TargetID) {
276 Impl->TargetPasses[StandardID] = TargetID;
279 AnalysisID TargetPassConfig::getPassSubstitution(AnalysisID ID) const {
280 DenseMap<AnalysisID, AnalysisID>::const_iterator
281 I = Impl->TargetPasses.find(ID);
282 if (I == Impl->TargetPasses.end())
287 /// Add a pass to the PassManager if that pass is supposed to be run. If the
288 /// Started/Stopped flags indicate either that the compilation should start at
289 /// a later pass or that it should stop after an earlier pass, then do not add
290 /// the pass. Finally, compare the current pass against the StartAfter
291 /// and StopAfter options and change the Started/Stopped flags accordingly.
292 void TargetPassConfig::addPass(Pass *P) {
293 assert(!Initialized && "PassConfig is immutable");
295 // Cache the Pass ID here in case the pass manager finds this pass is
296 // redundant with ones already scheduled / available, and deletes it.
297 // Fundamentally, once we add the pass to the manager, we no longer own it
298 // and shouldn't reference it.
299 AnalysisID PassID = P->getPassID();
301 if (Started && !Stopped)
303 if (StopAfter == PassID)
305 if (StartAfter == PassID)
307 if (Stopped && !Started)
308 report_fatal_error("Cannot stop compilation after pass that is not run");
311 /// Add a CodeGen pass at this point in the pipeline after checking for target
312 /// and command line overrides.
313 AnalysisID TargetPassConfig::addPass(AnalysisID PassID) {
314 AnalysisID TargetID = getPassSubstitution(PassID);
315 AnalysisID FinalID = overridePass(PassID, TargetID);
319 Pass *P = Pass::createPass(FinalID);
321 llvm_unreachable("Pass ID not registered");
323 // Add the passes after the pass P if there is any.
324 for (SmallVector<std::pair<AnalysisID, AnalysisID>, 4>::iterator
325 I = Impl->InsertedPasses.begin(), E = Impl->InsertedPasses.end();
327 if ((*I).first == PassID) {
328 assert((*I).second && "Illegal Pass ID!");
329 Pass *NP = Pass::createPass((*I).second);
330 assert(NP && "Pass ID not registered");
337 void TargetPassConfig::printAndVerify(const char *Banner) {
338 if (TM->shouldPrintMachineCode())
339 addPass(createMachineFunctionPrinterPass(dbgs(), Banner));
341 if (VerifyMachineCode)
342 addPass(createMachineVerifierPass(Banner));
345 /// Add common target configurable passes that perform LLVM IR to IR transforms
346 /// following machine independent optimization.
347 void TargetPassConfig::addIRPasses() {
348 // Basic AliasAnalysis support.
349 // Add TypeBasedAliasAnalysis before BasicAliasAnalysis so that
350 // BasicAliasAnalysis wins if they disagree. This is intended to help
351 // support "obvious" type-punning idioms.
352 addPass(createTypeBasedAliasAnalysisPass());
353 addPass(createBasicAliasAnalysisPass());
355 // Before running any passes, run the verifier to determine if the input
356 // coming from the front-end and/or optimizer is valid.
358 addPass(createVerifierPass());
360 // Run loop strength reduction before anything else.
361 if (getOptLevel() != CodeGenOpt::None && !DisableLSR) {
362 addPass(createLoopStrengthReducePass(getTargetLowering()));
364 addPass(createPrintFunctionPass("\n\n*** Code after LSR ***\n", &dbgs()));
367 addPass(createGCLoweringPass());
369 // Make sure that no unreachable blocks are instruction selected.
370 addPass(createUnreachableBlockEliminationPass());
373 /// Turn exception handling constructs into something the code generators can
375 void TargetPassConfig::addPassesToHandleExceptions() {
376 switch (TM->getMCAsmInfo()->getExceptionHandlingType()) {
377 case ExceptionHandling::SjLj:
378 // SjLj piggy-backs on dwarf for this bit. The cleanups done apply to both
379 // Dwarf EH prepare needs to be run after SjLj prepare. Otherwise,
380 // catch info can get misplaced when a selector ends up more than one block
381 // removed from the parent invoke(s). This could happen when a landing
382 // pad is shared by multiple invokes and is also a target of a normal
383 // edge from elsewhere.
384 addPass(createSjLjEHPreparePass(TM->getTargetLowering()));
386 case ExceptionHandling::DwarfCFI:
387 case ExceptionHandling::ARM:
388 case ExceptionHandling::Win64:
389 addPass(createDwarfEHPass(TM));
391 case ExceptionHandling::None:
392 addPass(createLowerInvokePass(TM->getTargetLowering()));
394 // The lower invoke pass may create unreachable code. Remove it.
395 addPass(createUnreachableBlockEliminationPass());
400 /// Add common passes that perform LLVM IR to IR transforms in preparation for
401 /// instruction selection.
402 void TargetPassConfig::addISelPrepare() {
403 if (getOptLevel() != CodeGenOpt::None && !DisableCGP)
404 addPass(createCodeGenPreparePass(getTargetLowering()));
406 addPass(createStackProtectorPass(getTargetLowering()));
411 addPass(createPrintFunctionPass("\n\n"
412 "*** Final LLVM Code input to ISel ***\n",
415 // All passes which modify the LLVM IR are now complete; run the verifier
416 // to ensure that the IR is valid.
418 addPass(createVerifierPass());
421 /// Add the complete set of target-independent postISel code generator passes.
423 /// This can be read as the standard order of major LLVM CodeGen stages. Stages
424 /// with nontrivial configuration or multiple passes are broken out below in
425 /// add%Stage routines.
427 /// Any TargetPassConfig::addXX routine may be overriden by the Target. The
428 /// addPre/Post methods with empty header implementations allow injecting
429 /// target-specific fixups just before or after major stages. Additionally,
430 /// targets have the flexibility to change pass order within a stage by
431 /// overriding default implementation of add%Stage routines below. Each
432 /// technique has maintainability tradeoffs because alternate pass orders are
433 /// not well supported. addPre/Post works better if the target pass is easily
434 /// tied to a common pass. But if it has subtle dependencies on multiple passes,
435 /// the target should override the stage instead.
437 /// TODO: We could use a single addPre/Post(ID) hook to allow pass injection
438 /// before/after any target-independent pass. But it's currently overkill.
439 void TargetPassConfig::addMachinePasses() {
440 // Insert a machine instr printer pass after the specified pass.
441 // If -print-machineinstrs specified, print machineinstrs after all passes.
442 if (StringRef(PrintMachineInstrs.getValue()).equals(""))
443 TM->Options.PrintMachineCode = true;
444 else if (!StringRef(PrintMachineInstrs.getValue())
445 .equals("option-unspecified")) {
446 const PassRegistry *PR = PassRegistry::getPassRegistry();
447 const PassInfo *TPI = PR->getPassInfo(PrintMachineInstrs.getValue());
448 const PassInfo *IPI = PR->getPassInfo(StringRef("print-machineinstrs"));
449 assert (TPI && IPI && "Pass ID not registered!");
450 const char *TID = (char *)(TPI->getTypeInfo());
451 const char *IID = (char *)(IPI->getTypeInfo());
452 insertPass(TID, IID);
455 // Print the instruction selected machine code...
456 printAndVerify("After Instruction Selection");
458 // Expand pseudo-instructions emitted by ISel.
459 if (addPass(&ExpandISelPseudosID))
460 printAndVerify("After ExpandISelPseudos");
462 // Add passes that optimize machine instructions in SSA form.
463 if (getOptLevel() != CodeGenOpt::None) {
464 addMachineSSAOptimization();
467 // If the target requests it, assign local variables to stack slots relative
468 // to one another and simplify frame index references where possible.
469 addPass(&LocalStackSlotAllocationID);
472 // Run pre-ra passes.
473 if (addPreRegAlloc())
474 printAndVerify("After PreRegAlloc passes");
476 // Run register allocation and passes that are tightly coupled with it,
477 // including phi elimination and scheduling.
478 if (getOptimizeRegAlloc())
479 addOptimizedRegAlloc(createRegAllocPass(true));
481 addFastRegAlloc(createRegAllocPass(false));
483 // Run post-ra passes.
484 if (addPostRegAlloc())
485 printAndVerify("After PostRegAlloc passes");
487 // Insert prolog/epilog code. Eliminate abstract frame index references...
488 addPass(&PrologEpilogCodeInserterID);
489 printAndVerify("After PrologEpilogCodeInserter");
491 /// Add passes that optimize machine instructions after register allocation.
492 if (getOptLevel() != CodeGenOpt::None)
493 addMachineLateOptimization();
495 // Expand pseudo instructions before second scheduling pass.
496 addPass(&ExpandPostRAPseudosID);
497 printAndVerify("After ExpandPostRAPseudos");
499 // Run pre-sched2 passes.
501 printAndVerify("After PreSched2 passes");
503 // Second pass scheduler.
504 if (getOptLevel() != CodeGenOpt::None) {
505 addPass(&PostRASchedulerID);
506 printAndVerify("After PostRAScheduler");
510 addPass(&GCMachineCodeAnalysisID);
512 addPass(createGCInfoPrinter(dbgs()));
514 // Basic block placement.
515 if (getOptLevel() != CodeGenOpt::None)
518 if (addPreEmitPass())
519 printAndVerify("After PreEmit passes");
522 /// Add passes that optimize machine instructions in SSA form.
523 void TargetPassConfig::addMachineSSAOptimization() {
524 // Pre-ra tail duplication.
525 if (addPass(&EarlyTailDuplicateID))
526 printAndVerify("After Pre-RegAlloc TailDuplicate");
528 // Optimize PHIs before DCE: removing dead PHI cycles may make more
529 // instructions dead.
530 addPass(&OptimizePHIsID);
532 // If the target requests it, assign local variables to stack slots relative
533 // to one another and simplify frame index references where possible.
534 addPass(&LocalStackSlotAllocationID);
536 // With optimization, dead code should already be eliminated. However
537 // there is one known exception: lowered code for arguments that are only
538 // used by tail calls, where the tail calls reuse the incoming stack
539 // arguments directly (see t11 in test/CodeGen/X86/sibcall.ll).
540 addPass(&DeadMachineInstructionElimID);
541 printAndVerify("After codegen DCE pass");
543 addPass(&EarlyIfConverterID);
544 addPass(&MachineLICMID);
545 addPass(&MachineCSEID);
546 addPass(&MachineSinkingID);
547 printAndVerify("After Machine LICM, CSE and Sinking passes");
549 addPass(&PeepholeOptimizerID);
550 printAndVerify("After codegen peephole optimization pass");
553 //===---------------------------------------------------------------------===//
554 /// Register Allocation Pass Configuration
555 //===---------------------------------------------------------------------===//
557 bool TargetPassConfig::getOptimizeRegAlloc() const {
558 switch (OptimizeRegAlloc) {
559 case cl::BOU_UNSET: return getOptLevel() != CodeGenOpt::None;
560 case cl::BOU_TRUE: return true;
561 case cl::BOU_FALSE: return false;
563 llvm_unreachable("Invalid optimize-regalloc state");
566 /// RegisterRegAlloc's global Registry tracks allocator registration.
567 MachinePassRegistry RegisterRegAlloc::Registry;
569 /// A dummy default pass factory indicates whether the register allocator is
570 /// overridden on the command line.
571 static FunctionPass *useDefaultRegisterAllocator() { return 0; }
572 static RegisterRegAlloc
573 defaultRegAlloc("default",
574 "pick register allocator based on -O option",
575 useDefaultRegisterAllocator);
577 /// -regalloc=... command line option.
578 static cl::opt<RegisterRegAlloc::FunctionPassCtor, false,
579 RegisterPassParser<RegisterRegAlloc> >
581 cl::init(&useDefaultRegisterAllocator),
582 cl::desc("Register allocator to use"));
585 /// Instantiate the default register allocator pass for this target for either
586 /// the optimized or unoptimized allocation path. This will be added to the pass
587 /// manager by addFastRegAlloc in the unoptimized case or addOptimizedRegAlloc
588 /// in the optimized case.
590 /// A target that uses the standard regalloc pass order for fast or optimized
591 /// allocation may still override this for per-target regalloc
592 /// selection. But -regalloc=... always takes precedence.
593 FunctionPass *TargetPassConfig::createTargetRegisterAllocator(bool Optimized) {
595 return createGreedyRegisterAllocator();
597 return createFastRegisterAllocator();
600 /// Find and instantiate the register allocation pass requested by this target
601 /// at the current optimization level. Different register allocators are
602 /// defined as separate passes because they may require different analysis.
604 /// This helper ensures that the regalloc= option is always available,
605 /// even for targets that override the default allocator.
607 /// FIXME: When MachinePassRegistry register pass IDs instead of function ptrs,
608 /// this can be folded into addPass.
609 FunctionPass *TargetPassConfig::createRegAllocPass(bool Optimized) {
610 RegisterRegAlloc::FunctionPassCtor Ctor = RegisterRegAlloc::getDefault();
612 // Initialize the global default.
615 RegisterRegAlloc::setDefault(RegAlloc);
617 if (Ctor != useDefaultRegisterAllocator)
620 // With no -regalloc= override, ask the target for a regalloc pass.
621 return createTargetRegisterAllocator(Optimized);
624 /// Add the minimum set of target-independent passes that are required for
625 /// register allocation. No coalescing or scheduling.
626 void TargetPassConfig::addFastRegAlloc(FunctionPass *RegAllocPass) {
627 addPass(&PHIEliminationID);
628 addPass(&TwoAddressInstructionPassID);
630 addPass(RegAllocPass);
631 printAndVerify("After Register Allocation");
634 /// Add standard target-independent passes that are tightly coupled with
635 /// optimized register allocation, including coalescing, machine instruction
636 /// scheduling, and register allocation itself.
637 void TargetPassConfig::addOptimizedRegAlloc(FunctionPass *RegAllocPass) {
638 addPass(&ProcessImplicitDefsID);
640 // LiveVariables currently requires pure SSA form.
642 // FIXME: Once TwoAddressInstruction pass no longer uses kill flags,
643 // LiveVariables can be removed completely, and LiveIntervals can be directly
644 // computed. (We still either need to regenerate kill flags after regalloc, or
645 // preferably fix the scavenger to not depend on them).
646 addPass(&LiveVariablesID);
648 // Add passes that move from transformed SSA into conventional SSA. This is a
649 // "copy coalescing" problem.
651 if (!EnableStrongPHIElim) {
652 // Edge splitting is smarter with machine loop info.
653 addPass(&MachineLoopInfoID);
654 addPass(&PHIEliminationID);
657 // Eventually, we want to run LiveIntervals before PHI elimination.
658 if (EarlyLiveIntervals)
659 addPass(&LiveIntervalsID);
661 addPass(&TwoAddressInstructionPassID);
663 if (EnableStrongPHIElim)
664 addPass(&StrongPHIEliminationID);
666 addPass(&RegisterCoalescerID);
668 // PreRA instruction scheduling.
669 if (addPass(&MachineSchedulerID))
670 printAndVerify("After Machine Scheduling");
672 // Add the selected register allocation pass.
673 addPass(RegAllocPass);
674 printAndVerify("After Register Allocation, before rewriter");
676 // Allow targets to change the register assignments before rewriting.
678 printAndVerify("After pre-rewrite passes");
680 // Finally rewrite virtual registers.
681 addPass(&VirtRegRewriterID);
682 printAndVerify("After Virtual Register Rewriter");
684 // FinalizeRegAlloc is convenient until MachineInstrBundles is more mature,
685 // but eventually, all users of it should probably be moved to addPostRA and
686 // it can go away. Currently, it's the intended place for targets to run
687 // FinalizeMachineBundles, because passes other than MachineScheduling an
688 // RegAlloc itself may not be aware of bundles.
689 if (addFinalizeRegAlloc())
690 printAndVerify("After RegAlloc finalization");
692 // Perform stack slot coloring and post-ra machine LICM.
694 // FIXME: Re-enable coloring with register when it's capable of adding
696 addPass(&StackSlotColoringID);
698 // Run post-ra machine LICM to hoist reloads / remats.
700 // FIXME: can this move into MachineLateOptimization?
701 addPass(&PostRAMachineLICMID);
703 printAndVerify("After StackSlotColoring and postra Machine LICM");
706 //===---------------------------------------------------------------------===//
707 /// Post RegAlloc Pass Configuration
708 //===---------------------------------------------------------------------===//
710 /// Add passes that optimize machine instructions after register allocation.
711 void TargetPassConfig::addMachineLateOptimization() {
712 // Branch folding must be run after regalloc and prolog/epilog insertion.
713 if (addPass(&BranchFolderPassID))
714 printAndVerify("After BranchFolding");
717 if (addPass(&TailDuplicateID))
718 printAndVerify("After TailDuplicate");
721 if (addPass(&MachineCopyPropagationID))
722 printAndVerify("After copy propagation pass");
725 /// Add standard basic block placement passes.
726 void TargetPassConfig::addBlockPlacement() {
727 AnalysisID PassID = 0;
728 if (!DisableBlockPlacement) {
729 // MachineBlockPlacement is a new pass which subsumes the functionality of
730 // CodPlacementOpt. The old code placement pass can be restored by
731 // disabling block placement, but eventually it will be removed.
732 PassID = addPass(&MachineBlockPlacementID);
734 PassID = addPass(&CodePlacementOptID);
737 // Run a separate pass to collect block placement statistics.
738 if (EnableBlockPlacementStats)
739 addPass(&MachineBlockPlacementStatsID);
741 printAndVerify("After machine block placement.");