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> DisableMachineLICM("disable-machine-licm", cl::Hidden,
53 cl::desc("Disable Machine LICM"));
54 static cl::opt<bool> DisableMachineCSE("disable-machine-cse", cl::Hidden,
55 cl::desc("Disable Machine Common Subexpression Elimination"));
56 static cl::opt<cl::boolOrDefault>
57 OptimizeRegAlloc("optimize-regalloc", cl::Hidden,
58 cl::desc("Enable optimized register allocation compilation path."));
59 static cl::opt<cl::boolOrDefault>
60 EnableMachineSched("enable-misched", cl::Hidden,
61 cl::desc("Enable the machine instruction scheduling pass."));
62 static cl::opt<bool> EnableStrongPHIElim("strong-phi-elim", cl::Hidden,
63 cl::desc("Use strong PHI elimination."));
64 static cl::opt<bool> DisablePostRAMachineLICM("disable-postra-machine-licm",
66 cl::desc("Disable Machine LICM"));
67 static cl::opt<bool> DisableMachineSink("disable-machine-sink", cl::Hidden,
68 cl::desc("Disable Machine Sinking"));
69 static cl::opt<bool> DisableLSR("disable-lsr", cl::Hidden,
70 cl::desc("Disable Loop Strength Reduction Pass"));
71 static cl::opt<bool> DisableCGP("disable-cgp", cl::Hidden,
72 cl::desc("Disable Codegen Prepare"));
73 static cl::opt<bool> DisableCopyProp("disable-copyprop", cl::Hidden,
74 cl::desc("Disable Copy Propagation pass"));
75 static cl::opt<bool> PrintLSR("print-lsr-output", cl::Hidden,
76 cl::desc("Print LLVM IR produced by the loop-reduce pass"));
77 static cl::opt<bool> PrintISelInput("print-isel-input", cl::Hidden,
78 cl::desc("Print LLVM IR input to isel pass"));
79 static cl::opt<bool> PrintGCInfo("print-gc", cl::Hidden,
80 cl::desc("Dump garbage collector data"));
81 static cl::opt<bool> VerifyMachineCode("verify-machineinstrs", cl::Hidden,
82 cl::desc("Verify generated machine code"),
83 cl::init(getenv("LLVM_VERIFY_MACHINEINSTRS")!=NULL));
84 static cl::opt<std::string>
85 PrintMachineInstrs("print-machineinstrs", cl::ValueOptional,
86 cl::desc("Print machine instrs"),
87 cl::value_desc("pass-name"), cl::init("option-unspecified"));
89 /// Allow standard passes to be disabled by command line options. This supports
90 /// simple binary flags that either suppress the pass or do nothing.
91 /// i.e. -disable-mypass=false has no effect.
92 /// These should be converted to boolOrDefault in order to use applyOverride.
93 static AnalysisID applyDisable(AnalysisID PassID, bool Override) {
99 /// Allow Pass selection to be overriden by command line options. This supports
100 /// flags with ternary conditions. TargetID is passed through by default. The
101 /// pass is suppressed when the option is false. When the option is true, the
102 /// StandardID is selected if the target provides no default.
103 static AnalysisID applyOverride(AnalysisID TargetID, cl::boolOrDefault Override,
104 AnalysisID StandardID) {
112 report_fatal_error("Target cannot enable pass");
117 llvm_unreachable("Invalid command line option state");
120 /// Allow standard passes to be disabled by the command line, regardless of who
121 /// is adding the pass.
123 /// StandardID is the pass identified in the standard pass pipeline and provided
124 /// to addPass(). It may be a target-specific ID in the case that the target
125 /// directly adds its own pass, but in that case we harmlessly fall through.
127 /// TargetID is the pass that the target has configured to override StandardID.
129 /// StandardID may be a pseudo ID. In that case TargetID is the name of the real
130 /// pass to run. This allows multiple options to control a single pass depending
131 /// on where in the pipeline that pass is added.
132 static AnalysisID overridePass(AnalysisID StandardID, AnalysisID TargetID) {
133 if (StandardID == &PostRASchedulerID)
134 return applyDisable(TargetID, DisablePostRA);
136 if (StandardID == &BranchFolderPassID)
137 return applyDisable(TargetID, DisableBranchFold);
139 if (StandardID == &TailDuplicateID)
140 return applyDisable(TargetID, DisableTailDuplicate);
142 if (StandardID == &TargetPassConfig::EarlyTailDuplicateID)
143 return applyDisable(TargetID, DisableEarlyTailDup);
145 if (StandardID == &MachineBlockPlacementID)
146 return applyDisable(TargetID, DisableCodePlace);
148 if (StandardID == &CodePlacementOptID)
149 return applyDisable(TargetID, DisableCodePlace);
151 if (StandardID == &StackSlotColoringID)
152 return applyDisable(TargetID, DisableSSC);
154 if (StandardID == &DeadMachineInstructionElimID)
155 return applyDisable(TargetID, DisableMachineDCE);
157 if (StandardID == &MachineLICMID)
158 return applyDisable(TargetID, DisableMachineLICM);
160 if (StandardID == &MachineCSEID)
161 return applyDisable(TargetID, DisableMachineCSE);
163 if (StandardID == &MachineSchedulerID)
164 return applyOverride(TargetID, EnableMachineSched, StandardID);
166 if (StandardID == &TargetPassConfig::PostRAMachineLICMID)
167 return applyDisable(TargetID, DisablePostRAMachineLICM);
169 if (StandardID == &MachineSinkingID)
170 return applyDisable(TargetID, DisableMachineSink);
172 if (StandardID == &MachineCopyPropagationID)
173 return applyDisable(TargetID, DisableCopyProp);
178 //===---------------------------------------------------------------------===//
180 //===---------------------------------------------------------------------===//
182 INITIALIZE_PASS(TargetPassConfig, "targetpassconfig",
183 "Target Pass Configuration", false, false)
184 char TargetPassConfig::ID = 0;
187 char TargetPassConfig::EarlyTailDuplicateID = 0;
188 char TargetPassConfig::PostRAMachineLICMID = 0;
191 class PassConfigImpl {
193 // List of passes explicitly substituted by this target. Normally this is
194 // empty, but it is a convenient way to suppress or replace specific passes
195 // that are part of a standard pass pipeline without overridding the entire
196 // pipeline. This mechanism allows target options to inherit a standard pass's
197 // user interface. For example, a target may disable a standard pass by
198 // default by substituting a pass ID of zero, and the user may still enable
199 // that standard pass with an explicit command line option.
200 DenseMap<AnalysisID,AnalysisID> TargetPasses;
202 /// Store the pairs of <AnalysisID, AnalysisID> of which the second pass
203 /// is inserted after each instance of the first one.
204 SmallVector<std::pair<AnalysisID, AnalysisID>, 4> InsertedPasses;
208 // Out of line virtual method.
209 TargetPassConfig::~TargetPassConfig() {
213 // Out of line constructor provides default values for pass options and
214 // registers all common codegen passes.
215 TargetPassConfig::TargetPassConfig(TargetMachine *tm, PassManagerBase &pm)
216 : ImmutablePass(ID), PM(&pm), StartAfter(0), StopAfter(0),
217 Started(true), Stopped(false), TM(tm), Impl(0), Initialized(false),
218 DisableVerify(false),
219 EnableTailMerge(true) {
221 Impl = new PassConfigImpl();
223 // Register all target independent codegen passes to activate their PassIDs,
224 // including this pass itself.
225 initializeCodeGen(*PassRegistry::getPassRegistry());
227 // Substitute Pseudo Pass IDs for real ones.
228 substitutePass(&EarlyTailDuplicateID, &TailDuplicateID);
229 substitutePass(&PostRAMachineLICMID, &MachineLICMID);
231 // Temporarily disable experimental passes.
232 substitutePass(&MachineSchedulerID, 0);
235 /// Insert InsertedPassID pass after TargetPassID.
236 void TargetPassConfig::insertPass(AnalysisID TargetPassID,
237 AnalysisID InsertedPassID) {
238 assert(TargetPassID != InsertedPassID && "Insert a pass after itself!");
239 std::pair<AnalysisID, AnalysisID> P(TargetPassID, InsertedPassID);
240 Impl->InsertedPasses.push_back(P);
243 /// createPassConfig - Create a pass configuration object to be used by
244 /// addPassToEmitX methods for generating a pipeline of CodeGen passes.
246 /// Targets may override this to extend TargetPassConfig.
247 TargetPassConfig *LLVMTargetMachine::createPassConfig(PassManagerBase &PM) {
248 return new TargetPassConfig(this, PM);
251 TargetPassConfig::TargetPassConfig()
252 : ImmutablePass(ID), PM(0) {
253 llvm_unreachable("TargetPassConfig should not be constructed on-the-fly");
256 // Helper to verify the analysis is really immutable.
257 void TargetPassConfig::setOpt(bool &Opt, bool Val) {
258 assert(!Initialized && "PassConfig is immutable");
262 void TargetPassConfig::substitutePass(AnalysisID StandardID,
263 AnalysisID TargetID) {
264 Impl->TargetPasses[StandardID] = TargetID;
267 AnalysisID TargetPassConfig::getPassSubstitution(AnalysisID ID) const {
268 DenseMap<AnalysisID, AnalysisID>::const_iterator
269 I = Impl->TargetPasses.find(ID);
270 if (I == Impl->TargetPasses.end())
275 /// Add a pass to the PassManager if that pass is supposed to be run. If the
276 /// Started/Stopped flags indicate either that the compilation should start at
277 /// a later pass or that it should stop after an earlier pass, then do not add
278 /// the pass. Finally, compare the current pass against the StartAfter
279 /// and StopAfter options and change the Started/Stopped flags accordingly.
280 void TargetPassConfig::addPass(Pass *P) {
281 assert(!Initialized && "PassConfig is immutable");
283 // Cache the Pass ID here in case the pass manager finds this pass is
284 // redundant with ones already scheduled / available, and deletes it.
285 // Fundamentally, once we add the pass to the manager, we no longer own it
286 // and shouldn't reference it.
287 AnalysisID PassID = P->getPassID();
289 if (Started && !Stopped)
291 if (StopAfter == PassID)
293 if (StartAfter == PassID)
295 if (Stopped && !Started)
296 report_fatal_error("Cannot stop compilation after pass that is not run");
299 /// Add a CodeGen pass at this point in the pipeline after checking for target
300 /// and command line overrides.
301 AnalysisID TargetPassConfig::addPass(AnalysisID PassID) {
302 AnalysisID TargetID = getPassSubstitution(PassID);
303 AnalysisID FinalID = overridePass(PassID, TargetID);
307 Pass *P = Pass::createPass(FinalID);
309 llvm_unreachable("Pass ID not registered");
311 // Add the passes after the pass P if there is any.
312 for (SmallVector<std::pair<AnalysisID, AnalysisID>, 4>::iterator
313 I = Impl->InsertedPasses.begin(), E = Impl->InsertedPasses.end();
315 if ((*I).first == PassID) {
316 assert((*I).second && "Illegal Pass ID!");
317 Pass *NP = Pass::createPass((*I).second);
318 assert(NP && "Pass ID not registered");
325 void TargetPassConfig::printAndVerify(const char *Banner) {
326 if (TM->shouldPrintMachineCode())
327 addPass(createMachineFunctionPrinterPass(dbgs(), Banner));
329 if (VerifyMachineCode)
330 addPass(createMachineVerifierPass(Banner));
333 /// Add common target configurable passes that perform LLVM IR to IR transforms
334 /// following machine independent optimization.
335 void TargetPassConfig::addIRPasses() {
336 // Basic AliasAnalysis support.
337 // Add TypeBasedAliasAnalysis before BasicAliasAnalysis so that
338 // BasicAliasAnalysis wins if they disagree. This is intended to help
339 // support "obvious" type-punning idioms.
340 addPass(createTypeBasedAliasAnalysisPass());
341 addPass(createBasicAliasAnalysisPass());
343 // Before running any passes, run the verifier to determine if the input
344 // coming from the front-end and/or optimizer is valid.
346 addPass(createVerifierPass());
348 // Run loop strength reduction before anything else.
349 if (getOptLevel() != CodeGenOpt::None && !DisableLSR) {
350 addPass(createLoopStrengthReducePass(getTargetLowering()));
352 addPass(createPrintFunctionPass("\n\n*** Code after LSR ***\n", &dbgs()));
355 addPass(createGCLoweringPass());
357 // Make sure that no unreachable blocks are instruction selected.
358 addPass(createUnreachableBlockEliminationPass());
361 /// Turn exception handling constructs into something the code generators can
363 void TargetPassConfig::addPassesToHandleExceptions() {
364 switch (TM->getMCAsmInfo()->getExceptionHandlingType()) {
365 case ExceptionHandling::SjLj:
366 // SjLj piggy-backs on dwarf for this bit. The cleanups done apply to both
367 // Dwarf EH prepare needs to be run after SjLj prepare. Otherwise,
368 // catch info can get misplaced when a selector ends up more than one block
369 // removed from the parent invoke(s). This could happen when a landing
370 // pad is shared by multiple invokes and is also a target of a normal
371 // edge from elsewhere.
372 addPass(createSjLjEHPreparePass(TM->getTargetLowering()));
374 case ExceptionHandling::DwarfCFI:
375 case ExceptionHandling::ARM:
376 case ExceptionHandling::Win64:
377 addPass(createDwarfEHPass(TM));
379 case ExceptionHandling::None:
380 addPass(createLowerInvokePass(TM->getTargetLowering()));
382 // The lower invoke pass may create unreachable code. Remove it.
383 addPass(createUnreachableBlockEliminationPass());
388 /// Add common passes that perform LLVM IR to IR transforms in preparation for
389 /// instruction selection.
390 void TargetPassConfig::addISelPrepare() {
391 if (getOptLevel() != CodeGenOpt::None && !DisableCGP)
392 addPass(createCodeGenPreparePass(getTargetLowering()));
394 addPass(createStackProtectorPass(getTargetLowering()));
399 addPass(createPrintFunctionPass("\n\n"
400 "*** Final LLVM Code input to ISel ***\n",
403 // All passes which modify the LLVM IR are now complete; run the verifier
404 // to ensure that the IR is valid.
406 addPass(createVerifierPass());
409 /// Add the complete set of target-independent postISel code generator passes.
411 /// This can be read as the standard order of major LLVM CodeGen stages. Stages
412 /// with nontrivial configuration or multiple passes are broken out below in
413 /// add%Stage routines.
415 /// Any TargetPassConfig::addXX routine may be overriden by the Target. The
416 /// addPre/Post methods with empty header implementations allow injecting
417 /// target-specific fixups just before or after major stages. Additionally,
418 /// targets have the flexibility to change pass order within a stage by
419 /// overriding default implementation of add%Stage routines below. Each
420 /// technique has maintainability tradeoffs because alternate pass orders are
421 /// not well supported. addPre/Post works better if the target pass is easily
422 /// tied to a common pass. But if it has subtle dependencies on multiple passes,
423 /// the target should override the stage instead.
425 /// TODO: We could use a single addPre/Post(ID) hook to allow pass injection
426 /// before/after any target-independent pass. But it's currently overkill.
427 void TargetPassConfig::addMachinePasses() {
428 // Print the instruction selected machine code...
429 printAndVerify("After Instruction Selection");
431 // Insert a machine instr printer pass after the specified pass.
432 // If -print-machineinstrs specified, print machineinstrs after all passes.
433 if (StringRef(PrintMachineInstrs.getValue()).equals(""))
434 TM->Options.PrintMachineCode = true;
435 else if (!StringRef(PrintMachineInstrs.getValue())
436 .equals("option-unspecified")) {
437 const PassRegistry *PR = PassRegistry::getPassRegistry();
438 const PassInfo *TPI = PR->getPassInfo(PrintMachineInstrs.getValue());
439 const PassInfo *IPI = PR->getPassInfo(StringRef("print-machineinstrs"));
440 assert (TPI && IPI && "Pass ID not registered!");
441 const char *TID = (char *)(TPI->getTypeInfo());
442 const char *IID = (char *)(IPI->getTypeInfo());
443 insertPass(TID, IID);
446 // Expand pseudo-instructions emitted by ISel.
447 addPass(&ExpandISelPseudosID);
449 // Add passes that optimize machine instructions in SSA form.
450 if (getOptLevel() != CodeGenOpt::None) {
451 addMachineSSAOptimization();
454 // If the target requests it, assign local variables to stack slots relative
455 // to one another and simplify frame index references where possible.
456 addPass(&LocalStackSlotAllocationID);
459 // Run pre-ra passes.
460 if (addPreRegAlloc())
461 printAndVerify("After PreRegAlloc passes");
463 // Run register allocation and passes that are tightly coupled with it,
464 // including phi elimination and scheduling.
465 if (getOptimizeRegAlloc())
466 addOptimizedRegAlloc(createRegAllocPass(true));
468 addFastRegAlloc(createRegAllocPass(false));
470 // Run post-ra passes.
471 if (addPostRegAlloc())
472 printAndVerify("After PostRegAlloc passes");
474 // Insert prolog/epilog code. Eliminate abstract frame index references...
475 addPass(&PrologEpilogCodeInserterID);
476 printAndVerify("After PrologEpilogCodeInserter");
478 /// Add passes that optimize machine instructions after register allocation.
479 if (getOptLevel() != CodeGenOpt::None)
480 addMachineLateOptimization();
482 // Expand pseudo instructions before second scheduling pass.
483 addPass(&ExpandPostRAPseudosID);
484 printAndVerify("After ExpandPostRAPseudos");
486 // Run pre-sched2 passes.
488 printAndVerify("After PreSched2 passes");
490 // Second pass scheduler.
491 if (getOptLevel() != CodeGenOpt::None) {
492 addPass(&PostRASchedulerID);
493 printAndVerify("After PostRAScheduler");
497 addPass(&GCMachineCodeAnalysisID);
499 addPass(createGCInfoPrinter(dbgs()));
501 // Basic block placement.
502 if (getOptLevel() != CodeGenOpt::None)
505 if (addPreEmitPass())
506 printAndVerify("After PreEmit passes");
509 /// Add passes that optimize machine instructions in SSA form.
510 void TargetPassConfig::addMachineSSAOptimization() {
511 // Pre-ra tail duplication.
512 if (addPass(&EarlyTailDuplicateID))
513 printAndVerify("After Pre-RegAlloc TailDuplicate");
515 // Optimize PHIs before DCE: removing dead PHI cycles may make more
516 // instructions dead.
517 addPass(&OptimizePHIsID);
519 // If the target requests it, assign local variables to stack slots relative
520 // to one another and simplify frame index references where possible.
521 addPass(&LocalStackSlotAllocationID);
523 // With optimization, dead code should already be eliminated. However
524 // there is one known exception: lowered code for arguments that are only
525 // used by tail calls, where the tail calls reuse the incoming stack
526 // arguments directly (see t11 in test/CodeGen/X86/sibcall.ll).
527 addPass(&DeadMachineInstructionElimID);
528 printAndVerify("After codegen DCE pass");
530 addPass(&MachineLICMID);
531 addPass(&MachineCSEID);
532 addPass(&MachineSinkingID);
533 printAndVerify("After Machine LICM, CSE and Sinking passes");
535 addPass(&PeepholeOptimizerID);
536 printAndVerify("After codegen peephole optimization pass");
539 //===---------------------------------------------------------------------===//
540 /// Register Allocation Pass Configuration
541 //===---------------------------------------------------------------------===//
543 bool TargetPassConfig::getOptimizeRegAlloc() const {
544 switch (OptimizeRegAlloc) {
545 case cl::BOU_UNSET: return getOptLevel() != CodeGenOpt::None;
546 case cl::BOU_TRUE: return true;
547 case cl::BOU_FALSE: return false;
549 llvm_unreachable("Invalid optimize-regalloc state");
552 /// RegisterRegAlloc's global Registry tracks allocator registration.
553 MachinePassRegistry RegisterRegAlloc::Registry;
555 /// A dummy default pass factory indicates whether the register allocator is
556 /// overridden on the command line.
557 static FunctionPass *useDefaultRegisterAllocator() { return 0; }
558 static RegisterRegAlloc
559 defaultRegAlloc("default",
560 "pick register allocator based on -O option",
561 useDefaultRegisterAllocator);
563 /// -regalloc=... command line option.
564 static cl::opt<RegisterRegAlloc::FunctionPassCtor, false,
565 RegisterPassParser<RegisterRegAlloc> >
567 cl::init(&useDefaultRegisterAllocator),
568 cl::desc("Register allocator to use"));
571 /// Instantiate the default register allocator pass for this target for either
572 /// the optimized or unoptimized allocation path. This will be added to the pass
573 /// manager by addFastRegAlloc in the unoptimized case or addOptimizedRegAlloc
574 /// in the optimized case.
576 /// A target that uses the standard regalloc pass order for fast or optimized
577 /// allocation may still override this for per-target regalloc
578 /// selection. But -regalloc=... always takes precedence.
579 FunctionPass *TargetPassConfig::createTargetRegisterAllocator(bool Optimized) {
581 return createGreedyRegisterAllocator();
583 return createFastRegisterAllocator();
586 /// Find and instantiate the register allocation pass requested by this target
587 /// at the current optimization level. Different register allocators are
588 /// defined as separate passes because they may require different analysis.
590 /// This helper ensures that the regalloc= option is always available,
591 /// even for targets that override the default allocator.
593 /// FIXME: When MachinePassRegistry register pass IDs instead of function ptrs,
594 /// this can be folded into addPass.
595 FunctionPass *TargetPassConfig::createRegAllocPass(bool Optimized) {
596 RegisterRegAlloc::FunctionPassCtor Ctor = RegisterRegAlloc::getDefault();
598 // Initialize the global default.
601 RegisterRegAlloc::setDefault(RegAlloc);
603 if (Ctor != useDefaultRegisterAllocator)
606 // With no -regalloc= override, ask the target for a regalloc pass.
607 return createTargetRegisterAllocator(Optimized);
610 /// Add the minimum set of target-independent passes that are required for
611 /// register allocation. No coalescing or scheduling.
612 void TargetPassConfig::addFastRegAlloc(FunctionPass *RegAllocPass) {
613 addPass(&PHIEliminationID);
614 addPass(&TwoAddressInstructionPassID);
616 addPass(RegAllocPass);
617 printAndVerify("After Register Allocation");
620 /// Add standard target-independent passes that are tightly coupled with
621 /// optimized register allocation, including coalescing, machine instruction
622 /// scheduling, and register allocation itself.
623 void TargetPassConfig::addOptimizedRegAlloc(FunctionPass *RegAllocPass) {
624 addPass(&ProcessImplicitDefsID);
626 // LiveVariables currently requires pure SSA form.
628 // FIXME: Once TwoAddressInstruction pass no longer uses kill flags,
629 // LiveVariables can be removed completely, and LiveIntervals can be directly
630 // computed. (We still either need to regenerate kill flags after regalloc, or
631 // preferably fix the scavenger to not depend on them).
632 addPass(&LiveVariablesID);
634 // Add passes that move from transformed SSA into conventional SSA. This is a
635 // "copy coalescing" problem.
637 if (!EnableStrongPHIElim) {
638 // Edge splitting is smarter with machine loop info.
639 addPass(&MachineLoopInfoID);
640 addPass(&PHIEliminationID);
642 addPass(&TwoAddressInstructionPassID);
644 if (EnableStrongPHIElim)
645 addPass(&StrongPHIEliminationID);
647 addPass(&RegisterCoalescerID);
649 // PreRA instruction scheduling.
650 if (addPass(&MachineSchedulerID))
651 printAndVerify("After Machine Scheduling");
653 // Add the selected register allocation pass.
654 addPass(RegAllocPass);
655 printAndVerify("After Register Allocation, before rewriter");
657 // Allow targets to change the register assignments before rewriting.
659 printAndVerify("After pre-rewrite passes");
661 // Finally rewrite virtual registers.
662 addPass(&VirtRegRewriterID);
663 printAndVerify("After Virtual Register Rewriter");
665 // FinalizeRegAlloc is convenient until MachineInstrBundles is more mature,
666 // but eventually, all users of it should probably be moved to addPostRA and
667 // it can go away. Currently, it's the intended place for targets to run
668 // FinalizeMachineBundles, because passes other than MachineScheduling an
669 // RegAlloc itself may not be aware of bundles.
670 if (addFinalizeRegAlloc())
671 printAndVerify("After RegAlloc finalization");
673 // Perform stack slot coloring and post-ra machine LICM.
675 // FIXME: Re-enable coloring with register when it's capable of adding
677 addPass(&StackSlotColoringID);
679 // Run post-ra machine LICM to hoist reloads / remats.
681 // FIXME: can this move into MachineLateOptimization?
682 addPass(&PostRAMachineLICMID);
684 printAndVerify("After StackSlotColoring and postra Machine LICM");
687 //===---------------------------------------------------------------------===//
688 /// Post RegAlloc Pass Configuration
689 //===---------------------------------------------------------------------===//
691 /// Add passes that optimize machine instructions after register allocation.
692 void TargetPassConfig::addMachineLateOptimization() {
693 // Branch folding must be run after regalloc and prolog/epilog insertion.
694 if (addPass(&BranchFolderPassID))
695 printAndVerify("After BranchFolding");
698 if (addPass(&TailDuplicateID))
699 printAndVerify("After TailDuplicate");
702 if (addPass(&MachineCopyPropagationID))
703 printAndVerify("After copy propagation pass");
706 /// Add standard basic block placement passes.
707 void TargetPassConfig::addBlockPlacement() {
708 AnalysisID PassID = 0;
709 if (!DisableBlockPlacement) {
710 // MachineBlockPlacement is a new pass which subsumes the functionality of
711 // CodPlacementOpt. The old code placement pass can be restored by
712 // disabling block placement, but eventually it will be removed.
713 PassID = addPass(&MachineBlockPlacementID);
715 PassID = addPass(&CodePlacementOptID);
718 // Run a separate pass to collect block placement statistics.
719 if (EnableBlockPlacementStats)
720 addPass(&MachineBlockPlacementStatsID);
722 printAndVerify("After machine block placement.");