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author | Dimitry Andric <dim@FreeBSD.org> | 2014-11-24 09:08:18 +0000 |
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committer | Dimitry Andric <dim@FreeBSD.org> | 2014-11-24 09:08:18 +0000 |
commit | 5ca98fd98791947eba83a1ed3f2c8191ef7afa6c (patch) | |
tree | f5944309621cee4fe0976be6f9ac619b7ebfc4c2 /lib/Analysis/AliasAnalysis.cpp | |
parent | 68bcb7db193e4bc81430063148253d30a791023e (diff) | |
download | src-5ca98fd98791947eba83a1ed3f2c8191ef7afa6c.tar.gz src-5ca98fd98791947eba83a1ed3f2c8191ef7afa6c.zip |
Vendor import of llvm RELEASE_350/final tag r216957 (effectively, 3.5.0 release):vendor/llvm/llvm-release_350-r216957
Notes
Notes:
svn path=/vendor/llvm/dist/; revision=274955
svn path=/vendor/llvm/llvm-release_35-r216957/; revision=274956; tag=vendor/llvm/llvm-release_350-r216957
Diffstat (limited to 'lib/Analysis/AliasAnalysis.cpp')
-rw-r--r-- | lib/Analysis/AliasAnalysis.cpp | 132 |
1 files changed, 62 insertions, 70 deletions
diff --git a/lib/Analysis/AliasAnalysis.cpp b/lib/Analysis/AliasAnalysis.cpp index b8b6d37a792f..8b8106b950a0 100644 --- a/lib/Analysis/AliasAnalysis.cpp +++ b/lib/Analysis/AliasAnalysis.cpp @@ -25,12 +25,12 @@ //===----------------------------------------------------------------------===// #include "llvm/Analysis/AliasAnalysis.h" -#include "llvm/Analysis/CaptureTracking.h" #include "llvm/Analysis/CFG.h" -#include "llvm/Analysis/Dominators.h" +#include "llvm/Analysis/CaptureTracking.h" #include "llvm/Analysis/ValueTracking.h" #include "llvm/IR/BasicBlock.h" #include "llvm/IR/DataLayout.h" +#include "llvm/IR/Dominators.h" #include "llvm/IR/Function.h" #include "llvm/IR/Instructions.h" #include "llvm/IR/IntrinsicInst.h" @@ -60,6 +60,13 @@ bool AliasAnalysis::pointsToConstantMemory(const Location &Loc, return AA->pointsToConstantMemory(Loc, OrLocal); } +AliasAnalysis::Location +AliasAnalysis::getArgLocation(ImmutableCallSite CS, unsigned ArgIdx, + AliasAnalysis::ModRefResult &Mask) { + assert(AA && "AA didn't call InitializeAliasAnalysis in its run method!"); + return AA->getArgLocation(CS, ArgIdx, Mask); +} + void AliasAnalysis::deleteValue(Value *V) { assert(AA && "AA didn't call InitializeAliasAnalysis in its run method!"); AA->deleteValue(V); @@ -91,22 +98,26 @@ AliasAnalysis::getModRefInfo(ImmutableCallSite CS, if (onlyAccessesArgPointees(MRB)) { bool doesAlias = false; + ModRefResult AllArgsMask = NoModRef; if (doesAccessArgPointees(MRB)) { - MDNode *CSTag = CS.getInstruction()->getMetadata(LLVMContext::MD_tbaa); for (ImmutableCallSite::arg_iterator AI = CS.arg_begin(), AE = CS.arg_end(); AI != AE; ++AI) { const Value *Arg = *AI; if (!Arg->getType()->isPointerTy()) continue; - Location CSLoc(Arg, UnknownSize, CSTag); + ModRefResult ArgMask; + Location CSLoc = + getArgLocation(CS, (unsigned) std::distance(CS.arg_begin(), AI), + ArgMask); if (!isNoAlias(CSLoc, Loc)) { doesAlias = true; - break; + AllArgsMask = ModRefResult(AllArgsMask | ArgMask); } } } if (!doesAlias) return NoModRef; + Mask = ModRefResult(Mask & AllArgsMask); } // If Loc is a constant memory location, the call definitely could not @@ -150,14 +161,23 @@ AliasAnalysis::getModRefInfo(ImmutableCallSite CS1, ImmutableCallSite CS2) { if (onlyAccessesArgPointees(CS2B)) { AliasAnalysis::ModRefResult R = NoModRef; if (doesAccessArgPointees(CS2B)) { - MDNode *CS2Tag = CS2.getInstruction()->getMetadata(LLVMContext::MD_tbaa); for (ImmutableCallSite::arg_iterator I = CS2.arg_begin(), E = CS2.arg_end(); I != E; ++I) { const Value *Arg = *I; if (!Arg->getType()->isPointerTy()) continue; - Location CS2Loc(Arg, UnknownSize, CS2Tag); - R = ModRefResult((R | getModRefInfo(CS1, CS2Loc)) & Mask); + ModRefResult ArgMask; + Location CS2Loc = + getArgLocation(CS2, (unsigned) std::distance(CS2.arg_begin(), I), + ArgMask); + // ArgMask indicates what CS2 might do to CS2Loc, and the dependence of + // CS1 on that location is the inverse. + if (ArgMask == Mod) + ArgMask = ModRef; + else if (ArgMask == Ref) + ArgMask = Mod; + + R = ModRefResult((R | (getModRefInfo(CS1, CS2Loc) & ArgMask)) & Mask); if (R == Mask) break; } @@ -170,21 +190,28 @@ AliasAnalysis::getModRefInfo(ImmutableCallSite CS1, ImmutableCallSite CS2) { if (onlyAccessesArgPointees(CS1B)) { AliasAnalysis::ModRefResult R = NoModRef; if (doesAccessArgPointees(CS1B)) { - MDNode *CS1Tag = CS1.getInstruction()->getMetadata(LLVMContext::MD_tbaa); for (ImmutableCallSite::arg_iterator I = CS1.arg_begin(), E = CS1.arg_end(); I != E; ++I) { const Value *Arg = *I; if (!Arg->getType()->isPointerTy()) continue; - Location CS1Loc(Arg, UnknownSize, CS1Tag); - if (getModRefInfo(CS2, CS1Loc) != NoModRef) { - R = Mask; + ModRefResult ArgMask; + Location CS1Loc = + getArgLocation(CS1, (unsigned) std::distance(CS1.arg_begin(), I), + ArgMask); + // ArgMask indicates what CS1 might do to CS1Loc; if CS1 might Mod + // CS1Loc, then we care about either a Mod or a Ref by CS2. If CS1 + // might Ref, then we care only about a Mod by CS2. + ModRefResult ArgR = getModRefInfo(CS2, CS1Loc); + if (((ArgMask & Mod) != NoModRef && (ArgR & ModRef) != NoModRef) || + ((ArgMask & Ref) != NoModRef && (ArgR & Mod) != NoModRef)) + R = ModRefResult((R | ArgMask) & Mask); + + if (R == Mask) break; - } } } - if (R == NoModRef) - return R; + return R; } // If this is the end of the chain, don't forward. @@ -338,7 +365,7 @@ AliasAnalysis::getModRefInfo(const VAArgInst *V, const Location &Loc) { AliasAnalysis::ModRefResult AliasAnalysis::getModRefInfo(const AtomicCmpXchgInst *CX, const Location &Loc) { // Acquire/Release cmpxchg has properties that matter for arbitrary addresses. - if (CX->getOrdering() > Monotonic) + if (CX->getSuccessOrdering() > Monotonic) return ModRef; // If the cmpxchg address does not alias the location, it does not access it. @@ -361,53 +388,6 @@ AliasAnalysis::getModRefInfo(const AtomicRMWInst *RMW, const Location &Loc) { return ModRef; } -namespace { - /// Only find pointer captures which happen before the given instruction. Uses - /// the dominator tree to determine whether one instruction is before another. - /// Only support the case where the Value is defined in the same basic block - /// as the given instruction and the use. - struct CapturesBefore : public CaptureTracker { - CapturesBefore(const Instruction *I, DominatorTree *DT) - : BeforeHere(I), DT(DT), Captured(false) {} - - void tooManyUses() { Captured = true; } - - bool shouldExplore(Use *U) { - Instruction *I = cast<Instruction>(U->getUser()); - BasicBlock *BB = I->getParent(); - // We explore this usage only if the usage can reach "BeforeHere". - // If use is not reachable from entry, there is no need to explore. - if (BeforeHere != I && !DT->isReachableFromEntry(BB)) - return false; - // If the value is defined in the same basic block as use and BeforeHere, - // there is no need to explore the use if BeforeHere dominates use. - // Check whether there is a path from I to BeforeHere. - if (BeforeHere != I && DT->dominates(BeforeHere, I) && - !isPotentiallyReachable(I, BeforeHere, DT)) - return false; - return true; - } - - bool captured(Use *U) { - Instruction *I = cast<Instruction>(U->getUser()); - BasicBlock *BB = I->getParent(); - // Same logic as in shouldExplore. - if (BeforeHere != I && !DT->isReachableFromEntry(BB)) - return false; - if (BeforeHere != I && DT->dominates(BeforeHere, I) && - !isPotentiallyReachable(I, BeforeHere, DT)) - return false; - Captured = true; - return true; - } - - const Instruction *BeforeHere; - DominatorTree *DT; - - bool Captured; - }; -} - // FIXME: this is really just shoring-up a deficiency in alias analysis. // BasicAA isn't willing to spend linear time determining whether an alloca // was captured before or after this particular call, while we are. However, @@ -416,9 +396,9 @@ AliasAnalysis::ModRefResult AliasAnalysis::callCapturesBefore(const Instruction *I, const AliasAnalysis::Location &MemLoc, DominatorTree *DT) { - if (!DT || !TD) return AliasAnalysis::ModRef; + if (!DT || !DL) return AliasAnalysis::ModRef; - const Value *Object = GetUnderlyingObject(MemLoc.Ptr, TD); + const Value *Object = GetUnderlyingObject(MemLoc.Ptr, DL); if (!isIdentifiedObject(Object) || isa<GlobalValue>(Object) || isa<Constant>(Object)) return AliasAnalysis::ModRef; @@ -427,9 +407,9 @@ AliasAnalysis::callCapturesBefore(const Instruction *I, if (!CS.getInstruction() || CS.getInstruction() == Object) return AliasAnalysis::ModRef; - CapturesBefore CB(I, DT); - llvm::PointerMayBeCaptured(Object, &CB); - if (CB.Captured) + if (llvm::PointerMayBeCapturedBefore(Object, /* ReturnCaptures */ true, + /* StoreCaptures */ true, I, DT, + /* include Object */ true)) return AliasAnalysis::ModRef; unsigned ArgNo = 0; @@ -472,7 +452,8 @@ AliasAnalysis::~AliasAnalysis() {} /// AliasAnalysis interface before any other methods are called. /// void AliasAnalysis::InitializeAliasAnalysis(Pass *P) { - TD = P->getAnalysisIfAvailable<DataLayout>(); + DataLayoutPass *DLP = P->getAnalysisIfAvailable<DataLayoutPass>(); + DL = DLP ? &DLP->getDataLayout() : nullptr; TLI = P->getAnalysisIfAvailable<TargetLibraryInfo>(); AA = &P->getAnalysis<AliasAnalysis>(); } @@ -487,7 +468,7 @@ void AliasAnalysis::getAnalysisUsage(AnalysisUsage &AU) const { /// if known, or a conservative value otherwise. /// uint64_t AliasAnalysis::getTypeStoreSize(Type *Ty) { - return TD ? TD->getTypeStoreSize(Ty) : UnknownSize; + return DL ? DL->getTypeStoreSize(Ty) : UnknownSize; } /// canBasicBlockModify - Return true if it is possible for execution of the @@ -554,3 +535,14 @@ bool llvm::isIdentifiedObject(const Value *V) { return A->hasNoAliasAttr() || A->hasByValAttr(); return false; } + +/// isIdentifiedFunctionLocal - Return true if V is umabigously identified +/// at the function-level. Different IdentifiedFunctionLocals can't alias. +/// Further, an IdentifiedFunctionLocal can not alias with any function +/// arguments other than itself, which is not necessarily true for +/// IdentifiedObjects. +bool llvm::isIdentifiedFunctionLocal(const Value *V) +{ + return isa<AllocaInst>(V) || isNoAliasCall(V) || isNoAliasArgument(V); +} + |