1 //==- AliasAnalysis.cpp - Generic Alias Analysis Interface Implementation --==//
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 implements the generic AliasAnalysis interface which is used as the
11 // common interface used by all clients and implementations of alias analysis.
13 // This file also implements the default version of the AliasAnalysis interface
14 // that is to be used when no other implementation is specified. This does some
15 // simple tests that detect obvious cases: two different global pointers cannot
16 // alias, a global cannot alias a malloc, two different mallocs cannot alias,
19 // This alias analysis implementation really isn't very good for anything, but
20 // it is very fast, and makes a nice clean default implementation. Because it
21 // handles lots of little corner cases, other, more complex, alias analysis
22 // implementations may choose to rely on this pass to resolve these simple and
25 //===----------------------------------------------------------------------===//
27 #include "llvm/Analysis/AliasAnalysis.h"
28 #include "llvm/Analysis/BasicAliasAnalysis.h"
29 #include "llvm/Analysis/CFLAndersAliasAnalysis.h"
30 #include "llvm/Analysis/CFLSteensAliasAnalysis.h"
31 #include "llvm/Analysis/CaptureTracking.h"
32 #include "llvm/Analysis/GlobalsModRef.h"
33 #include "llvm/Analysis/MemoryLocation.h"
34 #include "llvm/Analysis/ObjCARCAliasAnalysis.h"
35 #include "llvm/Analysis/ScalarEvolutionAliasAnalysis.h"
36 #include "llvm/Analysis/ScopedNoAliasAA.h"
37 #include "llvm/Analysis/TargetLibraryInfo.h"
38 #include "llvm/Analysis/TypeBasedAliasAnalysis.h"
39 #include "llvm/Analysis/ValueTracking.h"
40 #include "llvm/IR/Argument.h"
41 #include "llvm/IR/Attributes.h"
42 #include "llvm/IR/BasicBlock.h"
43 #include "llvm/IR/Instruction.h"
44 #include "llvm/IR/Instructions.h"
45 #include "llvm/IR/Module.h"
46 #include "llvm/IR/Type.h"
47 #include "llvm/IR/Value.h"
48 #include "llvm/Pass.h"
49 #include "llvm/Support/AtomicOrdering.h"
50 #include "llvm/Support/Casting.h"
51 #include "llvm/Support/CommandLine.h"
59 /// Allow disabling BasicAA from the AA results. This is particularly useful
60 /// when testing to isolate a single AA implementation.
61 static cl::opt<bool> DisableBasicAA("disable-basicaa", cl::Hidden,
64 AAResults::AAResults(AAResults &&Arg)
65 : TLI(Arg.TLI), AAs(std::move(Arg.AAs)), AADeps(std::move(Arg.AADeps)) {
67 AA->setAAResults(this);
70 AAResults::~AAResults() {
71 // FIXME; It would be nice to at least clear out the pointers back to this
72 // aggregation here, but we end up with non-nesting lifetimes in the legacy
73 // pass manager that prevent this from working. In the legacy pass manager
74 // we'll end up with dangling references here in some cases.
77 AA->setAAResults(nullptr);
81 bool AAResults::invalidate(Function &F, const PreservedAnalyses &PA,
82 FunctionAnalysisManager::Invalidator &Inv) {
83 // Check if the AA manager itself has been invalidated.
84 auto PAC = PA.getChecker<AAManager>();
85 if (!PAC.preserved() && !PAC.preservedSet<AllAnalysesOn<Function>>())
86 return true; // The manager needs to be blown away, clear everything.
88 // Check all of the dependencies registered.
89 for (AnalysisKey *ID : AADeps)
90 if (Inv.invalidate(ID, F, PA))
93 // Everything we depend on is still fine, so are we. Nothing to invalidate.
97 //===----------------------------------------------------------------------===//
98 // Default chaining methods
99 //===----------------------------------------------------------------------===//
101 AliasResult AAResults::alias(const MemoryLocation &LocA,
102 const MemoryLocation &LocB) {
103 for (const auto &AA : AAs) {
104 auto Result = AA->alias(LocA, LocB);
105 if (Result != MayAlias)
111 bool AAResults::pointsToConstantMemory(const MemoryLocation &Loc,
113 for (const auto &AA : AAs)
114 if (AA->pointsToConstantMemory(Loc, OrLocal))
120 ModRefInfo AAResults::getArgModRefInfo(const CallBase *Call, unsigned ArgIdx) {
121 ModRefInfo Result = ModRefInfo::ModRef;
123 for (const auto &AA : AAs) {
124 Result = intersectModRef(Result, AA->getArgModRefInfo(Call, ArgIdx));
126 // Early-exit the moment we reach the bottom of the lattice.
127 if (isNoModRef(Result))
128 return ModRefInfo::NoModRef;
134 ModRefInfo AAResults::getModRefInfo(Instruction *I, const CallBase *Call2) {
135 // We may have two calls.
136 if (const auto *Call1 = dyn_cast<CallBase>(I)) {
137 // Check if the two calls modify the same memory.
138 return getModRefInfo(Call1, Call2);
139 } else if (I->isFenceLike()) {
140 // If this is a fence, just return ModRef.
141 return ModRefInfo::ModRef;
143 // Otherwise, check if the call modifies or references the
144 // location this memory access defines. The best we can say
145 // is that if the call references what this instruction
146 // defines, it must be clobbered by this location.
147 const MemoryLocation DefLoc = MemoryLocation::get(I);
148 ModRefInfo MR = getModRefInfo(Call2, DefLoc);
149 if (isModOrRefSet(MR))
150 return setModAndRef(MR);
152 return ModRefInfo::NoModRef;
155 ModRefInfo AAResults::getModRefInfo(const CallBase *Call,
156 const MemoryLocation &Loc) {
157 ModRefInfo Result = ModRefInfo::ModRef;
159 for (const auto &AA : AAs) {
160 Result = intersectModRef(Result, AA->getModRefInfo(Call, Loc));
162 // Early-exit the moment we reach the bottom of the lattice.
163 if (isNoModRef(Result))
164 return ModRefInfo::NoModRef;
167 // Try to refine the mod-ref info further using other API entry points to the
168 // aggregate set of AA results.
169 auto MRB = getModRefBehavior(Call);
170 if (MRB == FMRB_DoesNotAccessMemory ||
171 MRB == FMRB_OnlyAccessesInaccessibleMem)
172 return ModRefInfo::NoModRef;
174 if (onlyReadsMemory(MRB))
175 Result = clearMod(Result);
176 else if (doesNotReadMemory(MRB))
177 Result = clearRef(Result);
179 if (onlyAccessesArgPointees(MRB) || onlyAccessesInaccessibleOrArgMem(MRB)) {
180 bool IsMustAlias = true;
181 ModRefInfo AllArgsMask = ModRefInfo::NoModRef;
182 if (doesAccessArgPointees(MRB)) {
183 for (auto AI = Call->arg_begin(), AE = Call->arg_end(); AI != AE; ++AI) {
184 const Value *Arg = *AI;
185 if (!Arg->getType()->isPointerTy())
187 unsigned ArgIdx = std::distance(Call->arg_begin(), AI);
188 MemoryLocation ArgLoc =
189 MemoryLocation::getForArgument(Call, ArgIdx, TLI);
190 AliasResult ArgAlias = alias(ArgLoc, Loc);
191 if (ArgAlias != NoAlias) {
192 ModRefInfo ArgMask = getArgModRefInfo(Call, ArgIdx);
193 AllArgsMask = unionModRef(AllArgsMask, ArgMask);
195 // Conservatively clear IsMustAlias unless only MustAlias is found.
196 IsMustAlias &= (ArgAlias == MustAlias);
199 // Return NoModRef if no alias found with any argument.
200 if (isNoModRef(AllArgsMask))
201 return ModRefInfo::NoModRef;
202 // Logical & between other AA analyses and argument analysis.
203 Result = intersectModRef(Result, AllArgsMask);
204 // If only MustAlias found above, set Must bit.
205 Result = IsMustAlias ? setMust(Result) : clearMust(Result);
208 // If Loc is a constant memory location, the call definitely could not
209 // modify the memory location.
210 if (isModSet(Result) && pointsToConstantMemory(Loc, /*OrLocal*/ false))
211 Result = clearMod(Result);
216 ModRefInfo AAResults::getModRefInfo(const CallBase *Call1,
217 const CallBase *Call2) {
218 ModRefInfo Result = ModRefInfo::ModRef;
220 for (const auto &AA : AAs) {
221 Result = intersectModRef(Result, AA->getModRefInfo(Call1, Call2));
223 // Early-exit the moment we reach the bottom of the lattice.
224 if (isNoModRef(Result))
225 return ModRefInfo::NoModRef;
228 // Try to refine the mod-ref info further using other API entry points to the
229 // aggregate set of AA results.
231 // If Call1 or Call2 are readnone, they don't interact.
232 auto Call1B = getModRefBehavior(Call1);
233 if (Call1B == FMRB_DoesNotAccessMemory)
234 return ModRefInfo::NoModRef;
236 auto Call2B = getModRefBehavior(Call2);
237 if (Call2B == FMRB_DoesNotAccessMemory)
238 return ModRefInfo::NoModRef;
240 // If they both only read from memory, there is no dependence.
241 if (onlyReadsMemory(Call1B) && onlyReadsMemory(Call2B))
242 return ModRefInfo::NoModRef;
244 // If Call1 only reads memory, the only dependence on Call2 can be
245 // from Call1 reading memory written by Call2.
246 if (onlyReadsMemory(Call1B))
247 Result = clearMod(Result);
248 else if (doesNotReadMemory(Call1B))
249 Result = clearRef(Result);
251 // If Call2 only access memory through arguments, accumulate the mod/ref
252 // information from Call1's references to the memory referenced by
253 // Call2's arguments.
254 if (onlyAccessesArgPointees(Call2B)) {
255 if (!doesAccessArgPointees(Call2B))
256 return ModRefInfo::NoModRef;
257 ModRefInfo R = ModRefInfo::NoModRef;
258 bool IsMustAlias = true;
259 for (auto I = Call2->arg_begin(), E = Call2->arg_end(); I != E; ++I) {
260 const Value *Arg = *I;
261 if (!Arg->getType()->isPointerTy())
263 unsigned Call2ArgIdx = std::distance(Call2->arg_begin(), I);
265 MemoryLocation::getForArgument(Call2, Call2ArgIdx, TLI);
267 // ArgModRefC2 indicates what Call2 might do to Call2ArgLoc, and the
268 // dependence of Call1 on that location is the inverse:
269 // - If Call2 modifies location, dependence exists if Call1 reads or
271 // - If Call2 only reads location, dependence exists if Call1 writes.
272 ModRefInfo ArgModRefC2 = getArgModRefInfo(Call2, Call2ArgIdx);
273 ModRefInfo ArgMask = ModRefInfo::NoModRef;
274 if (isModSet(ArgModRefC2))
275 ArgMask = ModRefInfo::ModRef;
276 else if (isRefSet(ArgModRefC2))
277 ArgMask = ModRefInfo::Mod;
279 // ModRefC1 indicates what Call1 might do to Call2ArgLoc, and we use
280 // above ArgMask to update dependence info.
281 ModRefInfo ModRefC1 = getModRefInfo(Call1, Call2ArgLoc);
282 ArgMask = intersectModRef(ArgMask, ModRefC1);
284 // Conservatively clear IsMustAlias unless only MustAlias is found.
285 IsMustAlias &= isMustSet(ModRefC1);
287 R = intersectModRef(unionModRef(R, ArgMask), Result);
289 // On early exit, not all args were checked, cannot set Must.
297 return ModRefInfo::NoModRef;
299 // If MustAlias found above, set Must bit.
300 return IsMustAlias ? setMust(R) : clearMust(R);
303 // If Call1 only accesses memory through arguments, check if Call2 references
304 // any of the memory referenced by Call1's arguments. If not, return NoModRef.
305 if (onlyAccessesArgPointees(Call1B)) {
306 if (!doesAccessArgPointees(Call1B))
307 return ModRefInfo::NoModRef;
308 ModRefInfo R = ModRefInfo::NoModRef;
309 bool IsMustAlias = true;
310 for (auto I = Call1->arg_begin(), E = Call1->arg_end(); I != E; ++I) {
311 const Value *Arg = *I;
312 if (!Arg->getType()->isPointerTy())
314 unsigned Call1ArgIdx = std::distance(Call1->arg_begin(), I);
316 MemoryLocation::getForArgument(Call1, Call1ArgIdx, TLI);
318 // ArgModRefC1 indicates what Call1 might do to Call1ArgLoc; if Call1
319 // might Mod Call1ArgLoc, then we care about either a Mod or a Ref by
320 // Call2. If Call1 might Ref, then we care only about a Mod by Call2.
321 ModRefInfo ArgModRefC1 = getArgModRefInfo(Call1, Call1ArgIdx);
322 ModRefInfo ModRefC2 = getModRefInfo(Call2, Call1ArgLoc);
323 if ((isModSet(ArgModRefC1) && isModOrRefSet(ModRefC2)) ||
324 (isRefSet(ArgModRefC1) && isModSet(ModRefC2)))
325 R = intersectModRef(unionModRef(R, ArgModRefC1), Result);
327 // Conservatively clear IsMustAlias unless only MustAlias is found.
328 IsMustAlias &= isMustSet(ModRefC2);
331 // On early exit, not all args were checked, cannot set Must.
339 return ModRefInfo::NoModRef;
341 // If MustAlias found above, set Must bit.
342 return IsMustAlias ? setMust(R) : clearMust(R);
348 FunctionModRefBehavior AAResults::getModRefBehavior(const CallBase *Call) {
349 FunctionModRefBehavior Result = FMRB_UnknownModRefBehavior;
351 for (const auto &AA : AAs) {
352 Result = FunctionModRefBehavior(Result & AA->getModRefBehavior(Call));
354 // Early-exit the moment we reach the bottom of the lattice.
355 if (Result == FMRB_DoesNotAccessMemory)
362 FunctionModRefBehavior AAResults::getModRefBehavior(const Function *F) {
363 FunctionModRefBehavior Result = FMRB_UnknownModRefBehavior;
365 for (const auto &AA : AAs) {
366 Result = FunctionModRefBehavior(Result & AA->getModRefBehavior(F));
368 // Early-exit the moment we reach the bottom of the lattice.
369 if (Result == FMRB_DoesNotAccessMemory)
376 raw_ostream &llvm::operator<<(raw_ostream &OS, AliasResult AR) {
388 OS << "PartialAlias";
394 //===----------------------------------------------------------------------===//
395 // Helper method implementation
396 //===----------------------------------------------------------------------===//
398 ModRefInfo AAResults::getModRefInfo(const LoadInst *L,
399 const MemoryLocation &Loc) {
400 // Be conservative in the face of atomic.
401 if (isStrongerThan(L->getOrdering(), AtomicOrdering::Unordered))
402 return ModRefInfo::ModRef;
404 // If the load address doesn't alias the given address, it doesn't read
405 // or write the specified memory.
407 AliasResult AR = alias(MemoryLocation::get(L), Loc);
409 return ModRefInfo::NoModRef;
411 return ModRefInfo::MustRef;
413 // Otherwise, a load just reads.
414 return ModRefInfo::Ref;
417 ModRefInfo AAResults::getModRefInfo(const StoreInst *S,
418 const MemoryLocation &Loc) {
419 // Be conservative in the face of atomic.
420 if (isStrongerThan(S->getOrdering(), AtomicOrdering::Unordered))
421 return ModRefInfo::ModRef;
424 AliasResult AR = alias(MemoryLocation::get(S), Loc);
425 // If the store address cannot alias the pointer in question, then the
426 // specified memory cannot be modified by the store.
428 return ModRefInfo::NoModRef;
430 // If the pointer is a pointer to constant memory, then it could not have
431 // been modified by this store.
432 if (pointsToConstantMemory(Loc))
433 return ModRefInfo::NoModRef;
435 // If the store address aliases the pointer as must alias, set Must.
437 return ModRefInfo::MustMod;
440 // Otherwise, a store just writes.
441 return ModRefInfo::Mod;
444 ModRefInfo AAResults::getModRefInfo(const FenceInst *S, const MemoryLocation &Loc) {
445 // If we know that the location is a constant memory location, the fence
446 // cannot modify this location.
447 if (Loc.Ptr && pointsToConstantMemory(Loc))
448 return ModRefInfo::Ref;
449 return ModRefInfo::ModRef;
452 ModRefInfo AAResults::getModRefInfo(const VAArgInst *V,
453 const MemoryLocation &Loc) {
455 AliasResult AR = alias(MemoryLocation::get(V), Loc);
456 // If the va_arg address cannot alias the pointer in question, then the
457 // specified memory cannot be accessed by the va_arg.
459 return ModRefInfo::NoModRef;
461 // If the pointer is a pointer to constant memory, then it could not have
462 // been modified by this va_arg.
463 if (pointsToConstantMemory(Loc))
464 return ModRefInfo::NoModRef;
466 // If the va_arg aliases the pointer as must alias, set Must.
468 return ModRefInfo::MustModRef;
471 // Otherwise, a va_arg reads and writes.
472 return ModRefInfo::ModRef;
475 ModRefInfo AAResults::getModRefInfo(const CatchPadInst *CatchPad,
476 const MemoryLocation &Loc) {
478 // If the pointer is a pointer to constant memory,
479 // then it could not have been modified by this catchpad.
480 if (pointsToConstantMemory(Loc))
481 return ModRefInfo::NoModRef;
484 // Otherwise, a catchpad reads and writes.
485 return ModRefInfo::ModRef;
488 ModRefInfo AAResults::getModRefInfo(const CatchReturnInst *CatchRet,
489 const MemoryLocation &Loc) {
491 // If the pointer is a pointer to constant memory,
492 // then it could not have been modified by this catchpad.
493 if (pointsToConstantMemory(Loc))
494 return ModRefInfo::NoModRef;
497 // Otherwise, a catchret reads and writes.
498 return ModRefInfo::ModRef;
501 ModRefInfo AAResults::getModRefInfo(const AtomicCmpXchgInst *CX,
502 const MemoryLocation &Loc) {
503 // Acquire/Release cmpxchg has properties that matter for arbitrary addresses.
504 if (isStrongerThanMonotonic(CX->getSuccessOrdering()))
505 return ModRefInfo::ModRef;
508 AliasResult AR = alias(MemoryLocation::get(CX), Loc);
509 // If the cmpxchg address does not alias the location, it does not access
512 return ModRefInfo::NoModRef;
514 // If the cmpxchg address aliases the pointer as must alias, set Must.
516 return ModRefInfo::MustModRef;
519 return ModRefInfo::ModRef;
522 ModRefInfo AAResults::getModRefInfo(const AtomicRMWInst *RMW,
523 const MemoryLocation &Loc) {
524 // Acquire/Release atomicrmw has properties that matter for arbitrary addresses.
525 if (isStrongerThanMonotonic(RMW->getOrdering()))
526 return ModRefInfo::ModRef;
529 AliasResult AR = alias(MemoryLocation::get(RMW), Loc);
530 // If the atomicrmw address does not alias the location, it does not access
533 return ModRefInfo::NoModRef;
535 // If the atomicrmw address aliases the pointer as must alias, set Must.
537 return ModRefInfo::MustModRef;
540 return ModRefInfo::ModRef;
543 /// Return information about whether a particular call site modifies
544 /// or reads the specified memory location \p MemLoc before instruction \p I
545 /// in a BasicBlock. An ordered basic block \p OBB can be used to speed up
546 /// instruction-ordering queries inside the BasicBlock containing \p I.
547 /// FIXME: this is really just shoring-up a deficiency in alias analysis.
548 /// BasicAA isn't willing to spend linear time determining whether an alloca
549 /// was captured before or after this particular call, while we are. However,
550 /// with a smarter AA in place, this test is just wasting compile time.
551 ModRefInfo AAResults::callCapturesBefore(const Instruction *I,
552 const MemoryLocation &MemLoc,
554 OrderedBasicBlock *OBB) {
556 return ModRefInfo::ModRef;
558 const Value *Object =
559 GetUnderlyingObject(MemLoc.Ptr, I->getModule()->getDataLayout());
560 if (!isIdentifiedObject(Object) || isa<GlobalValue>(Object) ||
561 isa<Constant>(Object))
562 return ModRefInfo::ModRef;
564 const auto *Call = dyn_cast<CallBase>(I);
565 if (!Call || Call == Object)
566 return ModRefInfo::ModRef;
568 if (PointerMayBeCapturedBefore(Object, /* ReturnCaptures */ true,
569 /* StoreCaptures */ true, I, DT,
570 /* include Object */ true,
571 /* OrderedBasicBlock */ OBB))
572 return ModRefInfo::ModRef;
575 ModRefInfo R = ModRefInfo::NoModRef;
576 bool IsMustAlias = true;
577 // Set flag only if no May found and all operands processed.
578 for (auto CI = Call->data_operands_begin(), CE = Call->data_operands_end();
579 CI != CE; ++CI, ++ArgNo) {
580 // Only look at the no-capture or byval pointer arguments. If this
581 // pointer were passed to arguments that were neither of these, then it
582 // couldn't be no-capture.
583 if (!(*CI)->getType()->isPointerTy() ||
584 (!Call->doesNotCapture(ArgNo) && ArgNo < Call->getNumArgOperands() &&
585 !Call->isByValArgument(ArgNo)))
588 AliasResult AR = alias(MemoryLocation(*CI), MemoryLocation(Object));
589 // If this is a no-capture pointer argument, see if we can tell that it
590 // is impossible to alias the pointer we're checking. If not, we have to
591 // assume that the call could touch the pointer, even though it doesn't
597 if (Call->doesNotAccessMemory(ArgNo))
599 if (Call->onlyReadsMemory(ArgNo)) {
603 // Not returning MustModRef since we have not seen all the arguments.
604 return ModRefInfo::ModRef;
606 return IsMustAlias ? setMust(R) : clearMust(R);
609 /// canBasicBlockModify - Return true if it is possible for execution of the
610 /// specified basic block to modify the location Loc.
612 bool AAResults::canBasicBlockModify(const BasicBlock &BB,
613 const MemoryLocation &Loc) {
614 return canInstructionRangeModRef(BB.front(), BB.back(), Loc, ModRefInfo::Mod);
617 /// canInstructionRangeModRef - Return true if it is possible for the
618 /// execution of the specified instructions to mod\ref (according to the
619 /// mode) the location Loc. The instructions to consider are all
620 /// of the instructions in the range of [I1,I2] INCLUSIVE.
621 /// I1 and I2 must be in the same basic block.
622 bool AAResults::canInstructionRangeModRef(const Instruction &I1,
623 const Instruction &I2,
624 const MemoryLocation &Loc,
625 const ModRefInfo Mode) {
626 assert(I1.getParent() == I2.getParent() &&
627 "Instructions not in same basic block!");
628 BasicBlock::const_iterator I = I1.getIterator();
629 BasicBlock::const_iterator E = I2.getIterator();
630 ++E; // Convert from inclusive to exclusive range.
632 for (; I != E; ++I) // Check every instruction in range
633 if (isModOrRefSet(intersectModRef(getModRefInfo(&*I, Loc), Mode)))
638 // Provide a definition for the root virtual destructor.
639 AAResults::Concept::~Concept() = default;
641 // Provide a definition for the static object used to identify passes.
642 AnalysisKey AAManager::Key;
647 } // end anonymous namespace
649 char ExternalAAWrapperPass::ID = 0;
651 INITIALIZE_PASS(ExternalAAWrapperPass, "external-aa", "External Alias Analysis",
655 llvm::createExternalAAWrapperPass(ExternalAAWrapperPass::CallbackT Callback) {
656 return new ExternalAAWrapperPass(std::move(Callback));
659 AAResultsWrapperPass::AAResultsWrapperPass() : FunctionPass(ID) {
660 initializeAAResultsWrapperPassPass(*PassRegistry::getPassRegistry());
663 char AAResultsWrapperPass::ID = 0;
665 INITIALIZE_PASS_BEGIN(AAResultsWrapperPass, "aa",
666 "Function Alias Analysis Results", false, true)
667 INITIALIZE_PASS_DEPENDENCY(BasicAAWrapperPass)
668 INITIALIZE_PASS_DEPENDENCY(CFLAndersAAWrapperPass)
669 INITIALIZE_PASS_DEPENDENCY(CFLSteensAAWrapperPass)
670 INITIALIZE_PASS_DEPENDENCY(ExternalAAWrapperPass)
671 INITIALIZE_PASS_DEPENDENCY(GlobalsAAWrapperPass)
672 INITIALIZE_PASS_DEPENDENCY(ObjCARCAAWrapperPass)
673 INITIALIZE_PASS_DEPENDENCY(SCEVAAWrapperPass)
674 INITIALIZE_PASS_DEPENDENCY(ScopedNoAliasAAWrapperPass)
675 INITIALIZE_PASS_DEPENDENCY(TypeBasedAAWrapperPass)
676 INITIALIZE_PASS_END(AAResultsWrapperPass, "aa",
677 "Function Alias Analysis Results", false, true)
679 FunctionPass *llvm::createAAResultsWrapperPass() {
680 return new AAResultsWrapperPass();
683 /// Run the wrapper pass to rebuild an aggregation over known AA passes.
685 /// This is the legacy pass manager's interface to the new-style AA results
686 /// aggregation object. Because this is somewhat shoe-horned into the legacy
687 /// pass manager, we hard code all the specific alias analyses available into
688 /// it. While the particular set enabled is configured via commandline flags,
689 /// adding a new alias analysis to LLVM will require adding support for it to
691 bool AAResultsWrapperPass::runOnFunction(Function &F) {
692 // NB! This *must* be reset before adding new AA results to the new
693 // AAResults object because in the legacy pass manager, each instance
694 // of these will refer to the *same* immutable analyses, registering and
695 // unregistering themselves with them. We need to carefully tear down the
696 // previous object first, in this case replacing it with an empty one, before
697 // registering new results.
699 new AAResults(getAnalysis<TargetLibraryInfoWrapperPass>().getTLI()));
701 // BasicAA is always available for function analyses. Also, we add it first
702 // so that it can trump TBAA results when it proves MustAlias.
703 // FIXME: TBAA should have an explicit mode to support this and then we
704 // should reconsider the ordering here.
706 AAR->addAAResult(getAnalysis<BasicAAWrapperPass>().getResult());
708 // Populate the results with the currently available AAs.
709 if (auto *WrapperPass = getAnalysisIfAvailable<ScopedNoAliasAAWrapperPass>())
710 AAR->addAAResult(WrapperPass->getResult());
711 if (auto *WrapperPass = getAnalysisIfAvailable<TypeBasedAAWrapperPass>())
712 AAR->addAAResult(WrapperPass->getResult());
713 if (auto *WrapperPass =
714 getAnalysisIfAvailable<objcarc::ObjCARCAAWrapperPass>())
715 AAR->addAAResult(WrapperPass->getResult());
716 if (auto *WrapperPass = getAnalysisIfAvailable<GlobalsAAWrapperPass>())
717 AAR->addAAResult(WrapperPass->getResult());
718 if (auto *WrapperPass = getAnalysisIfAvailable<SCEVAAWrapperPass>())
719 AAR->addAAResult(WrapperPass->getResult());
720 if (auto *WrapperPass = getAnalysisIfAvailable<CFLAndersAAWrapperPass>())
721 AAR->addAAResult(WrapperPass->getResult());
722 if (auto *WrapperPass = getAnalysisIfAvailable<CFLSteensAAWrapperPass>())
723 AAR->addAAResult(WrapperPass->getResult());
725 // If available, run an external AA providing callback over the results as
727 if (auto *WrapperPass = getAnalysisIfAvailable<ExternalAAWrapperPass>())
729 WrapperPass->CB(*this, F, *AAR);
731 // Analyses don't mutate the IR, so return false.
735 void AAResultsWrapperPass::getAnalysisUsage(AnalysisUsage &AU) const {
736 AU.setPreservesAll();
737 AU.addRequired<BasicAAWrapperPass>();
738 AU.addRequired<TargetLibraryInfoWrapperPass>();
740 // We also need to mark all the alias analysis passes we will potentially
741 // probe in runOnFunction as used here to ensure the legacy pass manager
742 // preserves them. This hard coding of lists of alias analyses is specific to
743 // the legacy pass manager.
744 AU.addUsedIfAvailable<ScopedNoAliasAAWrapperPass>();
745 AU.addUsedIfAvailable<TypeBasedAAWrapperPass>();
746 AU.addUsedIfAvailable<objcarc::ObjCARCAAWrapperPass>();
747 AU.addUsedIfAvailable<GlobalsAAWrapperPass>();
748 AU.addUsedIfAvailable<SCEVAAWrapperPass>();
749 AU.addUsedIfAvailable<CFLAndersAAWrapperPass>();
750 AU.addUsedIfAvailable<CFLSteensAAWrapperPass>();
753 AAResults llvm::createLegacyPMAAResults(Pass &P, Function &F,
754 BasicAAResult &BAR) {
755 AAResults AAR(P.getAnalysis<TargetLibraryInfoWrapperPass>().getTLI());
757 // Add in our explicitly constructed BasicAA results.
759 AAR.addAAResult(BAR);
761 // Populate the results with the other currently available AAs.
762 if (auto *WrapperPass =
763 P.getAnalysisIfAvailable<ScopedNoAliasAAWrapperPass>())
764 AAR.addAAResult(WrapperPass->getResult());
765 if (auto *WrapperPass = P.getAnalysisIfAvailable<TypeBasedAAWrapperPass>())
766 AAR.addAAResult(WrapperPass->getResult());
767 if (auto *WrapperPass =
768 P.getAnalysisIfAvailable<objcarc::ObjCARCAAWrapperPass>())
769 AAR.addAAResult(WrapperPass->getResult());
770 if (auto *WrapperPass = P.getAnalysisIfAvailable<GlobalsAAWrapperPass>())
771 AAR.addAAResult(WrapperPass->getResult());
772 if (auto *WrapperPass = P.getAnalysisIfAvailable<CFLAndersAAWrapperPass>())
773 AAR.addAAResult(WrapperPass->getResult());
774 if (auto *WrapperPass = P.getAnalysisIfAvailable<CFLSteensAAWrapperPass>())
775 AAR.addAAResult(WrapperPass->getResult());
780 bool llvm::isNoAliasCall(const Value *V) {
781 if (const auto *Call = dyn_cast<CallBase>(V))
782 return Call->hasRetAttr(Attribute::NoAlias);
786 bool llvm::isNoAliasArgument(const Value *V) {
787 if (const Argument *A = dyn_cast<Argument>(V))
788 return A->hasNoAliasAttr();
792 bool llvm::isIdentifiedObject(const Value *V) {
793 if (isa<AllocaInst>(V))
795 if (isa<GlobalValue>(V) && !isa<GlobalAlias>(V))
797 if (isNoAliasCall(V))
799 if (const Argument *A = dyn_cast<Argument>(V))
800 return A->hasNoAliasAttr() || A->hasByValAttr();
804 bool llvm::isIdentifiedFunctionLocal(const Value *V) {
805 return isa<AllocaInst>(V) || isNoAliasCall(V) || isNoAliasArgument(V);
808 void llvm::getAAResultsAnalysisUsage(AnalysisUsage &AU) {
809 // This function needs to be in sync with llvm::createLegacyPMAAResults -- if
810 // more alias analyses are added to llvm::createLegacyPMAAResults, they need
811 // to be added here also.
812 AU.addRequired<TargetLibraryInfoWrapperPass>();
813 AU.addUsedIfAvailable<ScopedNoAliasAAWrapperPass>();
814 AU.addUsedIfAvailable<TypeBasedAAWrapperPass>();
815 AU.addUsedIfAvailable<objcarc::ObjCARCAAWrapperPass>();
816 AU.addUsedIfAvailable<GlobalsAAWrapperPass>();
817 AU.addUsedIfAvailable<CFLAndersAAWrapperPass>();
818 AU.addUsedIfAvailable<CFLSteensAAWrapperPass>();