X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FAnalysis%2FMemoryDependenceAnalysis.cpp;h=fe1c8743a44f559d78500bd16254da18f737f224;hb=0a230e0d985625a3909cb78fd867a3abaf434565;hp=704e27b5ce6277fae584c6e460e50e40c4e30f89;hpb=9f47fb66370e5513bb9f737923e8cb476088acec;p=oota-llvm.git diff --git a/lib/Analysis/MemoryDependenceAnalysis.cpp b/lib/Analysis/MemoryDependenceAnalysis.cpp index 704e27b5ce6..fe1c8743a44 100644 --- a/lib/Analysis/MemoryDependenceAnalysis.cpp +++ b/lib/Analysis/MemoryDependenceAnalysis.cpp @@ -1,4 +1,4 @@ -//===- MemoryDependenceAnalysis.cpp - Mem Deps Implementation --*- C++ -*-===// +//===- MemoryDependenceAnalysis.cpp - Mem Deps Implementation -------------===// // // The LLVM Compiler Infrastructure // @@ -8,7 +8,7 @@ //===----------------------------------------------------------------------===// // // This file implements an analysis that determines, for a given memory -// operation, what preceding memory operations it depends on. It builds on +// operation, what preceding memory operations it depends on. It builds on // alias analysis information, and tries to provide a lazy, caching interface to // a common kind of alias information query. // @@ -16,23 +16,21 @@ #define DEBUG_TYPE "memdep" #include "llvm/Analysis/MemoryDependenceAnalysis.h" -#include "llvm/Analysis/ValueTracking.h" -#include "llvm/Instructions.h" -#include "llvm/IntrinsicInst.h" -#include "llvm/Function.h" -#include "llvm/LLVMContext.h" +#include "llvm/ADT/STLExtras.h" +#include "llvm/ADT/Statistic.h" #include "llvm/Analysis/AliasAnalysis.h" -#include "llvm/Analysis/CaptureTracking.h" #include "llvm/Analysis/Dominators.h" #include "llvm/Analysis/InstructionSimplify.h" #include "llvm/Analysis/MemoryBuiltins.h" #include "llvm/Analysis/PHITransAddr.h" #include "llvm/Analysis/ValueTracking.h" -#include "llvm/ADT/Statistic.h" -#include "llvm/ADT/STLExtras.h" -#include "llvm/Support/PredIteratorCache.h" +#include "llvm/IR/DataLayout.h" +#include "llvm/IR/Function.h" +#include "llvm/IR/Instructions.h" +#include "llvm/IR/IntrinsicInst.h" +#include "llvm/IR/LLVMContext.h" #include "llvm/Support/Debug.h" -#include "llvm/Target/TargetData.h" +#include "llvm/Support/PredIteratorCache.h" using namespace llvm; STATISTIC(NumCacheNonLocal, "Number of fully cached non-local responses"); @@ -49,12 +47,10 @@ STATISTIC(NumCacheCompleteNonLocalPtr, "Number of block queries that were completely cached"); // Limit for the number of instructions to scan in a block. -// FIXME: Figure out what a sane value is for this. -// (500 is relatively insane.) -static const int BlockScanLimit = 500; +static const int BlockScanLimit = 100; char MemoryDependenceAnalysis::ID = 0; - + // Register this pass... INITIALIZE_PASS_BEGIN(MemoryDependenceAnalysis, "memdep", "Memory Dependence Analysis", false, true) @@ -91,9 +87,9 @@ void MemoryDependenceAnalysis::getAnalysisUsage(AnalysisUsage &AU) const { bool MemoryDependenceAnalysis::runOnFunction(Function &) { AA = &getAnalysis(); - TD = getAnalysisIfAvailable(); + TD = getAnalysisIfAvailable(); DT = getAnalysisIfAvailable(); - if (PredCache == 0) + if (!PredCache) PredCache.reset(new PredIteratorCache()); return false; } @@ -101,7 +97,7 @@ bool MemoryDependenceAnalysis::runOnFunction(Function &) { /// RemoveFromReverseMap - This is a helper function that removes Val from /// 'Inst's set in ReverseMap. If the set becomes empty, remove Inst's entry. template -static void RemoveFromReverseMap(DenseMap > &ReverseMap, Instruction *Inst, KeyTy Val) { typename DenseMap >::iterator @@ -125,7 +121,8 @@ AliasAnalysis::ModRefResult GetLocation(const Instruction *Inst, if (LI->isUnordered()) { Loc = AA->getLocation(LI); return AliasAnalysis::Ref; - } else if (LI->getOrdering() == Monotonic) { + } + if (LI->getOrdering() == Monotonic) { Loc = AA->getLocation(LI); return AliasAnalysis::ModRef; } @@ -137,7 +134,8 @@ AliasAnalysis::ModRefResult GetLocation(const Instruction *Inst, if (SI->isUnordered()) { Loc = AA->getLocation(SI); return AliasAnalysis::Mod; - } else if (SI->getOrdering() == Monotonic) { + } + if (SI->getOrdering() == Monotonic) { Loc = AA->getLocation(SI); return AliasAnalysis::ModRef; } @@ -150,7 +148,7 @@ AliasAnalysis::ModRefResult GetLocation(const Instruction *Inst, return AliasAnalysis::ModRef; } - if (const CallInst *CI = isFreeCall(Inst)) { + if (const CallInst *CI = isFreeCall(Inst, AA->getTargetLibraryInfo())) { // calls to free() deallocate the entire structure Loc = AliasAnalysis::Location(CI->getArgOperand(0)); return AliasAnalysis::Mod; @@ -198,13 +196,13 @@ getCallSiteDependencyFrom(CallSite CS, bool isReadOnlyCall, // Walk backwards through the block, looking for dependencies while (ScanIt != BB->begin()) { // Limit the amount of scanning we do so we don't end up with quadratic - // running time on extreme testcases. + // running time on extreme testcases. --Limit; if (!Limit) return MemDepResult::getUnknown(); Instruction *Inst = --ScanIt; - + // If this inst is a memory op, get the pointer it accessed AliasAnalysis::Location Loc; AliasAnalysis::ModRefResult MR = GetLocation(Inst, Loc, AA); @@ -229,13 +227,18 @@ getCallSiteDependencyFrom(CallSite CS, bool isReadOnlyCall, // Otherwise if the two calls don't interact (e.g. InstCS is readnone) // keep scanning. - break; + continue; default: return MemDepResult::getClobber(Inst); } } + + // If we could not obtain a pointer for the instruction and the instruction + // touches memory then assume that this is a dependency. + if (MR != AliasAnalysis::NoModRef) + return MemDepResult::getClobber(Inst); } - + // No dependence found. If this is the entry block of the function, it is // unknown, otherwise it is non-local. if (BB != &BB->getParent()->getEntryBlock()) @@ -248,18 +251,18 @@ getCallSiteDependencyFrom(CallSite CS, bool isReadOnlyCall, /// /// MemLocBase, MemLocOffset are lazily computed here the first time the /// base/offs of memloc is needed. -static bool +static bool isLoadLoadClobberIfExtendedToFullWidth(const AliasAnalysis::Location &MemLoc, const Value *&MemLocBase, int64_t &MemLocOffs, const LoadInst *LI, - const TargetData *TD) { + const DataLayout *TD) { // If we have no target data, we can't do this. if (TD == 0) return false; // If we haven't already computed the base/offset of MemLoc, do so now. if (MemLocBase == 0) - MemLocBase = GetPointerBaseWithConstantOffset(MemLoc.Ptr, MemLocOffs, *TD); + MemLocBase = GetPointerBaseWithConstantOffset(MemLoc.Ptr, MemLocOffs, TD); unsigned Size = MemoryDependenceAnalysis:: getLoadLoadClobberFullWidthSize(MemLocBase, MemLocOffs, MemLoc.Size, @@ -277,28 +280,34 @@ isLoadLoadClobberIfExtendedToFullWidth(const AliasAnalysis::Location &MemLoc, unsigned MemoryDependenceAnalysis:: getLoadLoadClobberFullWidthSize(const Value *MemLocBase, int64_t MemLocOffs, unsigned MemLocSize, const LoadInst *LI, - const TargetData &TD) { + const DataLayout &TD) { // We can only extend simple integer loads. if (!isa(LI->getType()) || !LI->isSimple()) return 0; - + + // Load widening is hostile to ThreadSanitizer: it may cause false positives + // or make the reports more cryptic (access sizes are wrong). + if (LI->getParent()->getParent()->getAttributes(). + hasAttribute(AttributeSet::FunctionIndex, Attribute::SanitizeThread)) + return 0; + // Get the base of this load. int64_t LIOffs = 0; - const Value *LIBase = - GetPointerBaseWithConstantOffset(LI->getPointerOperand(), LIOffs, TD); - + const Value *LIBase = + GetPointerBaseWithConstantOffset(LI->getPointerOperand(), LIOffs, &TD); + // If the two pointers are not based on the same pointer, we can't tell that // they are related. if (LIBase != MemLocBase) return 0; - + // Okay, the two values are based on the same pointer, but returned as // no-alias. This happens when we have things like two byte loads at "P+1" // and "P+3". Check to see if increasing the size of the "LI" load up to its // alignment (or the largest native integer type) will allow us to load all // the bits required by MemLoc. - + // If MemLoc is before LI, then no widening of LI will help us out. if (MemLocOffs < LIOffs) return 0; - + // Get the alignment of the load in bytes. We assume that it is safe to load // any legal integer up to this size without a problem. For example, if we're // looking at an i8 load on x86-32 that is known 1024 byte aligned, we can @@ -307,15 +316,15 @@ getLoadLoadClobberFullWidthSize(const Value *MemLocBase, int64_t MemLocOffs, unsigned LoadAlign = LI->getAlignment(); int64_t MemLocEnd = MemLocOffs+MemLocSize; - + // If no amount of rounding up will let MemLoc fit into LI, then bail out. if (LIOffs+LoadAlign < MemLocEnd) return 0; - + // This is the size of the load to try. Start with the next larger power of // two. unsigned NewLoadByteSize = LI->getType()->getPrimitiveSizeInBits()/8U; NewLoadByteSize = NextPowerOf2(NewLoadByteSize); - + while (1) { // If this load size is bigger than our known alignment or would not fit // into a native integer register, then we fail. @@ -323,103 +332,42 @@ getLoadLoadClobberFullWidthSize(const Value *MemLocBase, int64_t MemLocOffs, !TD.fitsInLegalInteger(NewLoadByteSize*8)) return 0; + if (LIOffs+NewLoadByteSize > MemLocEnd && + LI->getParent()->getParent()->getAttributes(). + hasAttribute(AttributeSet::FunctionIndex, Attribute::SanitizeAddress)) + // We will be reading past the location accessed by the original program. + // While this is safe in a regular build, Address Safety analysis tools + // may start reporting false warnings. So, don't do widening. + return 0; + // If a load of this width would include all of MemLoc, then we succeed. if (LIOffs+NewLoadByteSize >= MemLocEnd) return NewLoadByteSize; - - NewLoadByteSize <<= 1; - } - - return 0; -} - -namespace { - /// Only find pointer captures which happen before the given instruction. Uses - /// the dominator tree to determine whether one instruction is before another. - 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(U->getUser()); - if (BeforeHere != I && DT->dominates(BeforeHere, I)) - return false; - return true; - } - - bool captured(Instruction *I) { - if (BeforeHere != I && DT->dominates(BeforeHere, I)) - return false; - Captured = true; - return true; - } - - const Instruction *BeforeHere; - DominatorTree *DT; - - bool Captured; - }; -} - -AliasAnalysis::ModRefResult -MemoryDependenceAnalysis::getModRefInfo(const Instruction *Inst, - const AliasAnalysis::Location &MemLoc) { - AliasAnalysis::ModRefResult MR = AA->getModRefInfo(Inst, MemLoc); - if (MR != AliasAnalysis::ModRef) return MR; - - // 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, - // with a smarter AA in place, this test is just wasting compile time. - if (!DT) return AliasAnalysis::ModRef; - const Value *Object = GetUnderlyingObject(MemLoc.Ptr, TD); - if (!isIdentifiedObject(Object) || isa(Object)) - return AliasAnalysis::ModRef; - ImmutableCallSite CS(Inst); - if (!CS.getInstruction()) return AliasAnalysis::ModRef; - CapturesBefore CB(Inst, DT); - llvm::PointerMayBeCaptured(Object, &CB); - - if (isa(Object) || CS.getInstruction() == Object || CB.Captured) - return AliasAnalysis::ModRef; - - unsigned ArgNo = 0; - for (ImmutableCallSite::arg_iterator CI = CS.arg_begin(), CE = CS.arg_end(); - CI != CE; ++CI, ++ArgNo) { - // Only look at the no-capture or byval pointer arguments. If this - // pointer were passed to arguments that were neither of these, then it - // couldn't be no-capture. - if (!(*CI)->getType()->isPointerTy() || - (!CS.doesNotCapture(ArgNo) && !CS.isByValArgument(ArgNo))) - continue; - - // If this is a no-capture pointer argument, see if we can tell that it - // is impossible to alias the pointer we're checking. If not, we have to - // assume that the call could touch the pointer, even though it doesn't - // escape. - if (!AA->isNoAlias(AliasAnalysis::Location(*CI), - AliasAnalysis::Location(Object))) { - return AliasAnalysis::ModRef; - } + NewLoadByteSize <<= 1; } - return AliasAnalysis::NoModRef; } /// getPointerDependencyFrom - Return the instruction on which a memory /// location depends. If isLoad is true, this routine ignores may-aliases with /// read-only operations. If isLoad is false, this routine ignores may-aliases -/// with reads from read-only locations. +/// with reads from read-only locations. If possible, pass the query +/// instruction as well; this function may take advantage of the metadata +/// annotated to the query instruction to refine the result. MemDepResult MemoryDependenceAnalysis:: -getPointerDependencyFrom(const AliasAnalysis::Location &MemLoc, bool isLoad, - BasicBlock::iterator ScanIt, BasicBlock *BB) { +getPointerDependencyFrom(const AliasAnalysis::Location &MemLoc, bool isLoad, + BasicBlock::iterator ScanIt, BasicBlock *BB, + Instruction *QueryInst) { const Value *MemLocBase = 0; int64_t MemLocOffset = 0; - unsigned Limit = BlockScanLimit; + bool isInvariantLoad = false; + if (isLoad && QueryInst) { + LoadInst *LI = dyn_cast(QueryInst); + if (LI && LI->getMetadata(LLVMContext::MD_invariant_load) != 0) + isInvariantLoad = true; + } // Walk backwards through the basic block, looking for dependencies. while (ScanIt != BB->begin()) { @@ -434,7 +382,7 @@ getPointerDependencyFrom(const AliasAnalysis::Location &MemLoc, bool isLoad, if (IntrinsicInst *II = dyn_cast(Inst)) { // Debug intrinsics don't (and can't) cause dependences. if (isa(II)) continue; - + // If we reach a lifetime begin or end marker, then the query ends here // because the value is undefined. if (II->getIntrinsicID() == Intrinsic::lifetime_start) { @@ -458,10 +406,10 @@ getPointerDependencyFrom(const AliasAnalysis::Location &MemLoc, bool isLoad, return MemDepResult::getClobber(LI); AliasAnalysis::Location LoadLoc = AA->getLocation(LI); - + // If we found a pointer, check if it could be the same as our pointer. AliasAnalysis::AliasResult R = AA->alias(LoadLoc, MemLoc); - + if (isLoad) { if (R == AliasAnalysis::NoAlias) { // If this is an over-aligned integer load (for example, @@ -475,10 +423,10 @@ getPointerDependencyFrom(const AliasAnalysis::Location &MemLoc, bool isLoad, isLoadLoadClobberIfExtendedToFullWidth(MemLoc, MemLocBase, MemLocOffset, LI, TD)) return MemDepResult::getClobber(Inst); - + continue; } - + // Must aliased loads are defs of each other. if (R == AliasAnalysis::MustAlias) return MemDepResult::getDef(Inst); @@ -493,7 +441,7 @@ getPointerDependencyFrom(const AliasAnalysis::Location &MemLoc, bool isLoad, if (R == AliasAnalysis::PartialAlias) return MemDepResult::getClobber(Inst); #endif - + // Random may-alias loads don't depend on each other without a // dependence. continue; @@ -510,7 +458,7 @@ getPointerDependencyFrom(const AliasAnalysis::Location &MemLoc, bool isLoad, // Stores depend on may/must aliased loads. return MemDepResult::getDef(Inst); } - + if (StoreInst *SI = dyn_cast(Inst)) { // Atomic stores have complications involved. // FIXME: This is overly conservative. @@ -526,14 +474,16 @@ getPointerDependencyFrom(const AliasAnalysis::Location &MemLoc, bool isLoad, // Ok, this store might clobber the query pointer. Check to see if it is // a must alias: in this case, we want to return this as a def. AliasAnalysis::Location StoreLoc = AA->getLocation(SI); - + // If we found a pointer, check if it could be the same as our pointer. AliasAnalysis::AliasResult R = AA->alias(StoreLoc, MemLoc); - + if (R == AliasAnalysis::NoAlias) continue; if (R == AliasAnalysis::MustAlias) return MemDepResult::getDef(Inst); + if (isInvariantLoad) + continue; return MemDepResult::getClobber(Inst); } @@ -545,17 +495,28 @@ getPointerDependencyFrom(const AliasAnalysis::Location &MemLoc, bool isLoad, // a subsequent bitcast of the malloc call result. There can be stores to // the malloced memory between the malloc call and its bitcast uses, and we // need to continue scanning until the malloc call. - if (isa(Inst) || - (isa(Inst) && extractMallocCall(Inst))) { + const TargetLibraryInfo *TLI = AA->getTargetLibraryInfo(); + if (isa(Inst) || isNoAliasFn(Inst, TLI)) { const Value *AccessPtr = GetUnderlyingObject(MemLoc.Ptr, TD); - + if (AccessPtr == Inst || AA->isMustAlias(Inst, AccessPtr)) return MemDepResult::getDef(Inst); - continue; + // Be conservative if the accessed pointer may alias the allocation. + if (AA->alias(Inst, AccessPtr) != AliasAnalysis::NoAlias) + return MemDepResult::getClobber(Inst); + // If the allocation is not aliased and does not read memory (like + // strdup), it is safe to ignore. + if (isa(Inst) || + isMallocLikeFn(Inst, TLI) || isCallocLikeFn(Inst, TLI)) + continue; } // See if this instruction (e.g. a call or vaarg) mod/ref's the pointer. - switch (getModRefInfo(Inst, MemLoc)) { + AliasAnalysis::ModRefResult MR = AA->getModRefInfo(Inst, MemLoc); + // If necessary, perform additional analysis. + if (MR == AliasAnalysis::ModRef) + MR = AA->callCapturesBefore(Inst, MemLoc, DT); + switch (MR) { case AliasAnalysis::NoModRef: // If the call has no effect on the queried pointer, just ignore it. continue; @@ -571,7 +532,7 @@ getPointerDependencyFrom(const AliasAnalysis::Location &MemLoc, bool isLoad, return MemDepResult::getClobber(Inst); } } - + // No dependence found. If this is the entry block of the function, it is // unknown, otherwise it is non-local. if (BB != &BB->getParent()->getEntryBlock()) @@ -583,25 +544,25 @@ getPointerDependencyFrom(const AliasAnalysis::Location &MemLoc, bool isLoad, /// depends. MemDepResult MemoryDependenceAnalysis::getDependency(Instruction *QueryInst) { Instruction *ScanPos = QueryInst; - + // Check for a cached result MemDepResult &LocalCache = LocalDeps[QueryInst]; - + // If the cached entry is non-dirty, just return it. Note that this depends // on MemDepResult's default constructing to 'dirty'. if (!LocalCache.isDirty()) return LocalCache; - + // Otherwise, if we have a dirty entry, we know we can start the scan at that // instruction, which may save us some work. if (Instruction *Inst = LocalCache.getInst()) { ScanPos = Inst; - + RemoveFromReverseMap(ReverseLocalDeps, Inst, QueryInst); } - + BasicBlock *QueryParent = QueryInst->getParent(); - + // Do the scan. if (BasicBlock::iterator(QueryInst) == QueryParent->begin()) { // No dependence found. If this is the entry block of the function, it is @@ -620,7 +581,7 @@ MemDepResult MemoryDependenceAnalysis::getDependency(Instruction *QueryInst) { isLoad |= II->getIntrinsicID() == Intrinsic::lifetime_start; LocalCache = getPointerDependencyFrom(MemLoc, isLoad, ScanPos, - QueryParent); + QueryParent, QueryInst); } else if (isa(QueryInst) || isa(QueryInst)) { CallSite QueryCS(QueryInst); bool isReadOnly = AA->onlyReadsMemory(QueryCS); @@ -630,11 +591,11 @@ MemDepResult MemoryDependenceAnalysis::getDependency(Instruction *QueryInst) { // Non-memory instruction. LocalCache = MemDepResult::getUnknown(); } - + // Remember the result! if (Instruction *I = LocalCache.getInst()) ReverseLocalDeps[I].insert(QueryInst); - + return LocalCache; } @@ -675,7 +636,7 @@ MemoryDependenceAnalysis::getNonLocalCallDependency(CallSite QueryCS) { /// the uncached case, this starts out as the set of predecessors we care /// about. SmallVector DirtyBlocks; - + if (!Cache.empty()) { // Okay, we have a cache entry. If we know it is not dirty, just return it // with no computation. @@ -683,17 +644,17 @@ MemoryDependenceAnalysis::getNonLocalCallDependency(CallSite QueryCS) { ++NumCacheNonLocal; return Cache; } - + // If we already have a partially computed set of results, scan them to // determine what is dirty, seeding our initial DirtyBlocks worklist. for (NonLocalDepInfo::iterator I = Cache.begin(), E = Cache.end(); I != E; ++I) if (I->getResult().isDirty()) DirtyBlocks.push_back(I->getBB()); - + // Sort the cache so that we can do fast binary search lookups below. std::sort(Cache.begin(), Cache.end()); - + ++NumCacheDirtyNonLocal; //cerr << "CACHED CASE: " << DirtyBlocks.size() << " dirty: " // << Cache.size() << " cached: " << *QueryInst; @@ -704,45 +665,45 @@ MemoryDependenceAnalysis::getNonLocalCallDependency(CallSite QueryCS) { DirtyBlocks.push_back(*PI); ++NumUncacheNonLocal; } - + // isReadonlyCall - If this is a read-only call, we can be more aggressive. bool isReadonlyCall = AA->onlyReadsMemory(QueryCS); SmallPtrSet Visited; - + unsigned NumSortedEntries = Cache.size(); DEBUG(AssertSorted(Cache)); - + // Iterate while we still have blocks to update. while (!DirtyBlocks.empty()) { BasicBlock *DirtyBB = DirtyBlocks.back(); DirtyBlocks.pop_back(); - + // Already processed this block? if (!Visited.insert(DirtyBB)) continue; - + // Do a binary search to see if we already have an entry for this block in // the cache set. If so, find it. DEBUG(AssertSorted(Cache, NumSortedEntries)); - NonLocalDepInfo::iterator Entry = + NonLocalDepInfo::iterator Entry = std::upper_bound(Cache.begin(), Cache.begin()+NumSortedEntries, NonLocalDepEntry(DirtyBB)); if (Entry != Cache.begin() && prior(Entry)->getBB() == DirtyBB) --Entry; - + NonLocalDepEntry *ExistingResult = 0; - if (Entry != Cache.begin()+NumSortedEntries && + if (Entry != Cache.begin()+NumSortedEntries && Entry->getBB() == DirtyBB) { // If we already have an entry, and if it isn't already dirty, the block // is done. if (!Entry->getResult().isDirty()) continue; - + // Otherwise, remember this slot so we can update the value. ExistingResult = &*Entry; } - + // If the dirty entry has a pointer, start scanning from it so we don't have // to rescan the entire block. BasicBlock::iterator ScanPos = DirtyBB->end(); @@ -754,10 +715,10 @@ MemoryDependenceAnalysis::getNonLocalCallDependency(CallSite QueryCS) { QueryCS.getInstruction()); } } - + // Find out if this block has a local dependency for QueryInst. MemDepResult Dep; - + if (ScanPos != DirtyBB->begin()) { Dep = getCallSiteDependencyFrom(QueryCS, isReadonlyCall,ScanPos, DirtyBB); } else if (DirtyBB != &DirtyBB->getParent()->getEntryBlock()) { @@ -767,14 +728,14 @@ MemoryDependenceAnalysis::getNonLocalCallDependency(CallSite QueryCS) { } else { Dep = MemDepResult::getNonFuncLocal(); } - + // If we had a dirty entry for the block, update it. Otherwise, just add // a new entry. if (ExistingResult) ExistingResult->setResult(Dep); else Cache.push_back(NonLocalDepEntry(DirtyBB, Dep)); - + // If the block has a dependency (i.e. it isn't completely transparent to // the value), remember the association! if (!Dep.isNonLocal()) { @@ -783,14 +744,14 @@ MemoryDependenceAnalysis::getNonLocalCallDependency(CallSite QueryCS) { if (Instruction *Inst = Dep.getInst()) ReverseNonLocalDeps[Inst].insert(QueryCS.getInstruction()); } else { - + // If the block *is* completely transparent to the load, we need to check // the predecessors of this block. Add them to our worklist. for (BasicBlock **PI = PredCache->GetPreds(DirtyBB); *PI; ++PI) DirtyBlocks.push_back(*PI); } } - + return Cache; } @@ -808,9 +769,9 @@ getNonLocalPointerDependency(const AliasAnalysis::Location &Loc, bool isLoad, assert(Loc.Ptr->getType()->isPointerTy() && "Can't get pointer deps of a non-pointer!"); Result.clear(); - + PHITransAddr Address(const_cast(Loc.Ptr), TD); - + // This is the set of blocks we've inspected, and the pointer we consider in // each block. Because of critical edges, we currently bail out if querying // a block with multiple different pointers. This can happen during PHI @@ -833,7 +794,7 @@ MemDepResult MemoryDependenceAnalysis:: GetNonLocalInfoForBlock(const AliasAnalysis::Location &Loc, bool isLoad, BasicBlock *BB, NonLocalDepInfo *Cache, unsigned NumSortedEntries) { - + // Do a binary search to see if we already have an entry for this block in // the cache set. If so, find it. NonLocalDepInfo::iterator Entry = @@ -841,18 +802,18 @@ GetNonLocalInfoForBlock(const AliasAnalysis::Location &Loc, NonLocalDepEntry(BB)); if (Entry != Cache->begin() && (Entry-1)->getBB() == BB) --Entry; - + NonLocalDepEntry *ExistingResult = 0; if (Entry != Cache->begin()+NumSortedEntries && Entry->getBB() == BB) ExistingResult = &*Entry; - + // If we have a cached entry, and it is non-dirty, use it as the value for // this dependency. if (ExistingResult && !ExistingResult->getResult().isDirty()) { ++NumCacheNonLocalPtr; return ExistingResult->getResult(); - } - + } + // Otherwise, we have to scan for the value. If we have a dirty cache // entry, start scanning from its position, otherwise we scan from the end // of the block. @@ -862,30 +823,30 @@ GetNonLocalInfoForBlock(const AliasAnalysis::Location &Loc, "Instruction invalidated?"); ++NumCacheDirtyNonLocalPtr; ScanPos = ExistingResult->getResult().getInst(); - + // Eliminating the dirty entry from 'Cache', so update the reverse info. ValueIsLoadPair CacheKey(Loc.Ptr, isLoad); RemoveFromReverseMap(ReverseNonLocalPtrDeps, ScanPos, CacheKey); } else { ++NumUncacheNonLocalPtr; } - + // Scan the block for the dependency. MemDepResult Dep = getPointerDependencyFrom(Loc, isLoad, ScanPos, BB); - + // If we had a dirty entry for the block, update it. Otherwise, just add // a new entry. if (ExistingResult) ExistingResult->setResult(Dep); else Cache->push_back(NonLocalDepEntry(BB, Dep)); - + // If the block has a dependency (i.e. it isn't completely transparent to // the value), remember the reverse association because we just added it // to Cache! if (!Dep.isDef() && !Dep.isClobber()) return Dep; - + // Keep the ReverseNonLocalPtrDeps map up to date so we can efficiently // update MemDep when we remove instructions. Instruction *Inst = Dep.getInst(); @@ -898,7 +859,7 @@ GetNonLocalInfoForBlock(const AliasAnalysis::Location &Loc, /// SortNonLocalDepInfoCache - Sort the a NonLocalDepInfo cache, given a certain /// number of elements in the array that are already properly ordered. This is /// optimized for the case when only a few entries are added. -static void +static void SortNonLocalDepInfoCache(MemoryDependenceAnalysis::NonLocalDepInfo &Cache, unsigned NumSortedEntries) { switch (Cache.size() - NumSortedEntries) { @@ -950,7 +911,6 @@ getNonLocalPointerDepFromBB(const PHITransAddr &Pointer, SmallVectorImpl &Result, DenseMap &Visited, bool SkipFirstBlock) { - // Look up the cached info for Pointer. ValueIsLoadPair CacheKey(Pointer.getAddr(), isLoad); @@ -964,7 +924,7 @@ getNonLocalPointerDepFromBB(const PHITransAddr &Pointer, // Get the NLPI for CacheKey, inserting one into the map if it doesn't // already have one. - std::pair Pair = + std::pair Pair = NonLocalPointerDeps.insert(std::make_pair(CacheKey, InitialNLPI)); NonLocalPointerInfo *CacheInfo = &Pair.first->second; @@ -973,7 +933,7 @@ getNonLocalPointerDepFromBB(const PHITransAddr &Pointer, if (!Pair.second) { if (CacheInfo->Size < Loc.Size) { // The query's Size is greater than the cached one. Throw out the - // cached data and procede with the query at the greater size. + // cached data and proceed with the query at the greater size. CacheInfo->Pair = BBSkipFirstBlockPair(); CacheInfo->Size = Loc.Size; for (NonLocalDepInfo::iterator DI = CacheInfo->NonLocalDeps.begin(), @@ -1026,25 +986,34 @@ getNonLocalPointerDepFromBB(const PHITransAddr &Pointer, DenseMap::iterator VI = Visited.find(I->getBB()); if (VI == Visited.end() || VI->second == Pointer.getAddr()) continue; - + // We have a pointer mismatch in a block. Just return clobber, saying // that something was clobbered in this result. We could also do a // non-fully cached query, but there is little point in doing this. return true; } } - + Value *Addr = Pointer.getAddr(); for (NonLocalDepInfo::iterator I = Cache->begin(), E = Cache->end(); I != E; ++I) { Visited.insert(std::make_pair(I->getBB(), Addr)); - if (!I->getResult().isNonLocal()) + if (I->getResult().isNonLocal()) { + continue; + } + + if (!DT) { + Result.push_back(NonLocalDepResult(I->getBB(), + MemDepResult::getUnknown(), + Addr)); + } else if (DT->isReachableFromEntry(I->getBB())) { Result.push_back(NonLocalDepResult(I->getBB(), I->getResult(), Addr)); + } } ++NumCacheCompleteNonLocalPtr; return false; } - + // Otherwise, either this is a new block, a block with an invalid cache // pointer or one that we're about to invalidate by putting more info into it // than its valid cache info. If empty, the result will be valid cache info, @@ -1053,10 +1022,10 @@ getNonLocalPointerDepFromBB(const PHITransAddr &Pointer, CacheInfo->Pair = BBSkipFirstBlockPair(StartBB, SkipFirstBlock); else CacheInfo->Pair = BBSkipFirstBlockPair(); - + SmallVector Worklist; Worklist.push_back(StartBB); - + // PredList used inside loop. SmallVector, 16> PredList; @@ -1067,10 +1036,10 @@ getNonLocalPointerDepFromBB(const PHITransAddr &Pointer, // revisit blocks after we insert info for them. unsigned NumSortedEntries = Cache->size(); DEBUG(AssertSorted(*Cache)); - + while (!Worklist.empty()) { BasicBlock *BB = Worklist.pop_back_val(); - + // Skip the first block if we have it. if (!SkipFirstBlock) { // Analyze the dependency of *Pointer in FromBB. See if we already have @@ -1082,14 +1051,21 @@ getNonLocalPointerDepFromBB(const PHITransAddr &Pointer, DEBUG(AssertSorted(*Cache, NumSortedEntries)); MemDepResult Dep = GetNonLocalInfoForBlock(Loc, isLoad, BB, Cache, NumSortedEntries); - + // If we got a Def or Clobber, add this to the list of results. if (!Dep.isNonLocal()) { - Result.push_back(NonLocalDepResult(BB, Dep, Pointer.getAddr())); - continue; + if (!DT) { + Result.push_back(NonLocalDepResult(BB, + MemDepResult::getUnknown(), + Pointer.getAddr())); + continue; + } else if (DT->isReachableFromEntry(BB)) { + Result.push_back(NonLocalDepResult(BB, Dep, Pointer.getAddr())); + continue; + } } } - + // If 'Pointer' is an instruction defined in this block, then we need to do // phi translation to change it into a value live in the predecessor block. // If not, we just add the predecessors to the worklist and scan them with @@ -1106,7 +1082,7 @@ getNonLocalPointerDepFromBB(const PHITransAddr &Pointer, NewBlocks.push_back(*PI); continue; } - + // If we have seen this block before, but it was with a different // pointer then we have a phi translation failure and we have to treat // this as a clobber. @@ -1121,12 +1097,12 @@ getNonLocalPointerDepFromBB(const PHITransAddr &Pointer, Worklist.append(NewBlocks.begin(), NewBlocks.end()); continue; } - + // We do need to do phi translation, if we know ahead of time we can't phi // translate this value, don't even try. if (!Pointer.IsPotentiallyPHITranslatable()) goto PredTranslationFailure; - + // We may have added values to the cache list before this PHI translation. // If so, we haven't done anything to ensure that the cache remains sorted. // Sort it now (if needed) so that recursive invocations of @@ -1149,7 +1125,7 @@ getNonLocalPointerDepFromBB(const PHITransAddr &Pointer, PredPointer.PHITranslateValue(BB, Pred, 0); Value *PredPtrVal = PredPointer.getAddr(); - + // Check to see if we have already visited this pred block with another // pointer. If so, we can't do this lookup. This failure can occur // with PHI translation when a critical edge exists and the PHI node in @@ -1166,14 +1142,14 @@ getNonLocalPointerDepFromBB(const PHITransAddr &Pointer, // the analysis and can ignore it. if (InsertRes.first->second == PredPtrVal) continue; - + // Otherwise, the block was previously analyzed with a different // pointer. We can't represent the result of this case, so we just // treat this as a phi translation failure. // Make sure to clean up the Visited map before continuing on to // PredTranslationFailure. - for (unsigned i = 0; i < PredList.size(); i++) + for (unsigned i = 0, n = PredList.size(); i < n; ++i) Visited.erase(PredList[i].first); goto PredTranslationFailure; @@ -1182,10 +1158,10 @@ getNonLocalPointerDepFromBB(const PHITransAddr &Pointer, // Actually process results here; this need to be a separate loop to avoid // calling getNonLocalPointerDepFromBB for blocks we don't want to return - // any results for. (getNonLocalPointerDepFromBB will modify our + // any results for. (getNonLocalPointerDepFromBB will modify our // datastructures in ways the code after the PredTranslationFailure label // doesn't expect.) - for (unsigned i = 0; i < PredList.size(); i++) { + for (unsigned i = 0, n = PredList.size(); i < n; ++i) { BasicBlock *Pred = PredList[i].first; PHITransAddr &PredPointer = PredList[i].second; Value *PredPtrVal = PredPointer.getAddr(); @@ -1225,12 +1201,12 @@ getNonLocalPointerDepFromBB(const PHITransAddr &Pointer, continue; } } - + // Refresh the CacheInfo/Cache pointer so that it isn't invalidated. CacheInfo = &NonLocalPointerDeps[CacheKey]; Cache = &CacheInfo->NonLocalDeps; NumSortedEntries = Cache->size(); - + // Since we did phi translation, the "Cache" set won't contain all of the // results for the query. This is ok (we can still use it to accelerate // specific block queries) but we can't do the fastpath "return all @@ -1243,20 +1219,20 @@ getNonLocalPointerDepFromBB(const PHITransAddr &Pointer, // The following code is "failure"; we can't produce a sane translation // for the given block. It assumes that we haven't modified any of // our datastructures while processing the current block. - + if (Cache == 0) { // Refresh the CacheInfo/Cache pointer if it got invalidated. CacheInfo = &NonLocalPointerDeps[CacheKey]; Cache = &CacheInfo->NonLocalDeps; NumSortedEntries = Cache->size(); } - + // Since we failed phi translation, the "Cache" set won't contain all of the // results for the query. This is ok (we can still use it to accelerate // specific block queries) but we can't do the fastpath "return all // results from the set". Clear out the indicator for this. CacheInfo->Pair = BBSkipFirstBlockPair(); - + // If *nothing* works, mark the pointer as unknown. // // If this is the magic first block, return this as a clobber of the whole @@ -1264,12 +1240,12 @@ getNonLocalPointerDepFromBB(const PHITransAddr &Pointer, // we have to bail out. if (SkipFirstBlock) return true; - + for (NonLocalDepInfo::reverse_iterator I = Cache->rbegin(); ; ++I) { assert(I != Cache->rend() && "Didn't find current block??"); if (I->getBB() != BB) continue; - + assert(I->getResult().isNonLocal() && "Should only be here with transparent block"); I->setResult(MemDepResult::getUnknown()); @@ -1289,23 +1265,23 @@ getNonLocalPointerDepFromBB(const PHITransAddr &Pointer, /// CachedNonLocalPointerInfo, remove it. void MemoryDependenceAnalysis:: RemoveCachedNonLocalPointerDependencies(ValueIsLoadPair P) { - CachedNonLocalPointerInfo::iterator It = + CachedNonLocalPointerInfo::iterator It = NonLocalPointerDeps.find(P); if (It == NonLocalPointerDeps.end()) return; - + // Remove all of the entries in the BB->val map. This involves removing // instructions from the reverse map. NonLocalDepInfo &PInfo = It->second.NonLocalDeps; - + for (unsigned i = 0, e = PInfo.size(); i != e; ++i) { Instruction *Target = PInfo[i].getResult().getInst(); if (Target == 0) continue; // Ignore non-local dep results. assert(Target->getParent() == PInfo[i].getBB()); - + // Eliminating the dirty entry from 'Cache', so update the reverse info. RemoveFromReverseMap(ReverseNonLocalPtrDeps, Target, P); } - + // Remove P from NonLocalPointerDeps (which deletes NonLocalDepInfo). NonLocalPointerDeps.erase(It); } @@ -1360,20 +1336,20 @@ void MemoryDependenceAnalysis::removeInstruction(Instruction *RemInst) { // Remove this local dependency info. LocalDeps.erase(LocalDepEntry); } - + // If we have any cached pointer dependencies on this instruction, remove // them. If the instruction has non-pointer type, then it can't be a pointer // base. - + // Remove it from both the load info and the store info. The instruction // can't be in either of these maps if it is non-pointer. if (RemInst->getType()->isPointerTy()) { RemoveCachedNonLocalPointerDependencies(ValueIsLoadPair(RemInst, false)); RemoveCachedNonLocalPointerDependencies(ValueIsLoadPair(RemInst, true)); } - + // Loop over all of the things that depend on the instruction we're removing. - // + // SmallVector, 8> ReverseDepsToAdd; // If we find RemInst as a clobber or Def in any of the maps for other values, @@ -1385,29 +1361,29 @@ void MemoryDependenceAnalysis::removeInstruction(Instruction *RemInst) { MemDepResult NewDirtyVal; if (!RemInst->isTerminator()) NewDirtyVal = MemDepResult::getDirty(++BasicBlock::iterator(RemInst)); - + ReverseDepMapType::iterator ReverseDepIt = ReverseLocalDeps.find(RemInst); if (ReverseDepIt != ReverseLocalDeps.end()) { SmallPtrSet &ReverseDeps = ReverseDepIt->second; // RemInst can't be the terminator if it has local stuff depending on it. assert(!ReverseDeps.empty() && !isa(RemInst) && "Nothing can locally depend on a terminator"); - + for (SmallPtrSet::iterator I = ReverseDeps.begin(), E = ReverseDeps.end(); I != E; ++I) { Instruction *InstDependingOnRemInst = *I; assert(InstDependingOnRemInst != RemInst && "Already removed our local dep info"); - + LocalDeps[InstDependingOnRemInst] = NewDirtyVal; - + // Make sure to remember that new things depend on NewDepInst. assert(NewDirtyVal.getInst() && "There is no way something else can have " "a local dep on this if it is a terminator!"); - ReverseDepsToAdd.push_back(std::make_pair(NewDirtyVal.getInst(), + ReverseDepsToAdd.push_back(std::make_pair(NewDirtyVal.getInst(), InstDependingOnRemInst)); } - + ReverseLocalDeps.erase(ReverseDepIt); // Add new reverse deps after scanning the set, to avoid invalidating the @@ -1418,25 +1394,25 @@ void MemoryDependenceAnalysis::removeInstruction(Instruction *RemInst) { ReverseDepsToAdd.pop_back(); } } - + ReverseDepIt = ReverseNonLocalDeps.find(RemInst); if (ReverseDepIt != ReverseNonLocalDeps.end()) { SmallPtrSet &Set = ReverseDepIt->second; for (SmallPtrSet::iterator I = Set.begin(), E = Set.end(); I != E; ++I) { assert(*I != RemInst && "Already removed NonLocalDep info for RemInst"); - + PerInstNLInfo &INLD = NonLocalDeps[*I]; // The information is now dirty! INLD.second = true; - - for (NonLocalDepInfo::iterator DI = INLD.first.begin(), + + for (NonLocalDepInfo::iterator DI = INLD.first.begin(), DE = INLD.first.end(); DI != DE; ++DI) { if (DI->getResult().getInst() != RemInst) continue; - + // Convert to a dirty entry for the subsequent instruction. DI->setResult(NewDirtyVal); - + if (Instruction *NextI = NewDirtyVal.getInst()) ReverseDepsToAdd.push_back(std::make_pair(NextI, *I)); } @@ -1451,7 +1427,7 @@ void MemoryDependenceAnalysis::removeInstruction(Instruction *RemInst) { ReverseDepsToAdd.pop_back(); } } - + // If the instruction is in ReverseNonLocalPtrDeps then it appears as a // value in the NonLocalPointerDeps info. ReverseNonLocalPtrDepTy::iterator ReversePtrDepIt = @@ -1459,45 +1435,45 @@ void MemoryDependenceAnalysis::removeInstruction(Instruction *RemInst) { if (ReversePtrDepIt != ReverseNonLocalPtrDeps.end()) { SmallPtrSet &Set = ReversePtrDepIt->second; SmallVector,8> ReversePtrDepsToAdd; - + for (SmallPtrSet::iterator I = Set.begin(), E = Set.end(); I != E; ++I) { ValueIsLoadPair P = *I; assert(P.getPointer() != RemInst && "Already removed NonLocalPointerDeps info for RemInst"); - + NonLocalDepInfo &NLPDI = NonLocalPointerDeps[P].NonLocalDeps; - + // The cache is not valid for any specific block anymore. NonLocalPointerDeps[P].Pair = BBSkipFirstBlockPair(); - + // Update any entries for RemInst to use the instruction after it. for (NonLocalDepInfo::iterator DI = NLPDI.begin(), DE = NLPDI.end(); DI != DE; ++DI) { if (DI->getResult().getInst() != RemInst) continue; - + // Convert to a dirty entry for the subsequent instruction. DI->setResult(NewDirtyVal); - + if (Instruction *NewDirtyInst = NewDirtyVal.getInst()) ReversePtrDepsToAdd.push_back(std::make_pair(NewDirtyInst, P)); } - + // Re-sort the NonLocalDepInfo. Changing the dirty entry to its // subsequent value may invalidate the sortedness. std::sort(NLPDI.begin(), NLPDI.end()); } - + ReverseNonLocalPtrDeps.erase(ReversePtrDepIt); - + while (!ReversePtrDepsToAdd.empty()) { ReverseNonLocalPtrDeps[ReversePtrDepsToAdd.back().first] .insert(ReversePtrDepsToAdd.back().second); ReversePtrDepsToAdd.pop_back(); } } - - + + assert(!NonLocalDeps.count(RemInst) && "RemInst got reinserted?"); AA->deleteValue(RemInst); DEBUG(verifyRemoved(RemInst)); @@ -1511,7 +1487,7 @@ void MemoryDependenceAnalysis::verifyRemoved(Instruction *D) const { assert(I->second.getInst() != D && "Inst occurs in data structures"); } - + for (CachedNonLocalPointerInfo::const_iterator I =NonLocalPointerDeps.begin(), E = NonLocalPointerDeps.end(); I != E; ++I) { assert(I->first.getPointer() != D && "Inst occurs in NLPD map key"); @@ -1520,7 +1496,7 @@ void MemoryDependenceAnalysis::verifyRemoved(Instruction *D) const { II != E; ++II) assert(II->getResult().getInst() != D && "Inst occurs as NLPD value"); } - + for (NonLocalDepMapType::const_iterator I = NonLocalDeps.begin(), E = NonLocalDeps.end(); I != E; ++I) { assert(I->first != D && "Inst occurs in data structures"); @@ -1529,7 +1505,7 @@ void MemoryDependenceAnalysis::verifyRemoved(Instruction *D) const { EE = INLD.first.end(); II != EE; ++II) assert(II->getResult().getInst() != D && "Inst occurs in data structures"); } - + for (ReverseDepMapType::const_iterator I = ReverseLocalDeps.begin(), E = ReverseLocalDeps.end(); I != E; ++I) { assert(I->first != D && "Inst occurs in data structures"); @@ -1537,7 +1513,7 @@ void MemoryDependenceAnalysis::verifyRemoved(Instruction *D) const { EE = I->second.end(); II != EE; ++II) assert(*II != D && "Inst occurs in data structures"); } - + for (ReverseDepMapType::const_iterator I = ReverseNonLocalDeps.begin(), E = ReverseNonLocalDeps.end(); I != E; ++I) { @@ -1546,17 +1522,17 @@ void MemoryDependenceAnalysis::verifyRemoved(Instruction *D) const { EE = I->second.end(); II != EE; ++II) assert(*II != D && "Inst occurs in data structures"); } - + for (ReverseNonLocalPtrDepTy::const_iterator I = ReverseNonLocalPtrDeps.begin(), E = ReverseNonLocalPtrDeps.end(); I != E; ++I) { assert(I->first != D && "Inst occurs in rev NLPD map"); - + for (SmallPtrSet::const_iterator II = I->second.begin(), E = I->second.end(); II != E; ++II) assert(*II != ValueIsLoadPair(D, false) && *II != ValueIsLoadPair(D, true) && "Inst occurs in ReverseNonLocalPtrDeps map"); } - + }