| //===- MemoryDependenceAnalysis.cpp - Mem Deps Implementation -------------===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file implements an analysis that determines, for a given memory |
| // 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. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "llvm/Analysis/MemoryDependenceAnalysis.h" |
| #include "llvm/ADT/DenseMap.h" |
| #include "llvm/ADT/STLExtras.h" |
| #include "llvm/ADT/SmallPtrSet.h" |
| #include "llvm/ADT/SmallVector.h" |
| #include "llvm/ADT/Statistic.h" |
| #include "llvm/Analysis/AliasAnalysis.h" |
| #include "llvm/Analysis/AssumptionCache.h" |
| #include "llvm/Analysis/MemoryBuiltins.h" |
| #include "llvm/Analysis/MemoryLocation.h" |
| #include "llvm/Analysis/PHITransAddr.h" |
| #include "llvm/Analysis/PhiValues.h" |
| #include "llvm/Analysis/TargetLibraryInfo.h" |
| #include "llvm/Analysis/ValueTracking.h" |
| #include "llvm/IR/Attributes.h" |
| #include "llvm/IR/BasicBlock.h" |
| #include "llvm/IR/Constants.h" |
| #include "llvm/IR/DataLayout.h" |
| #include "llvm/IR/DerivedTypes.h" |
| #include "llvm/IR/Dominators.h" |
| #include "llvm/IR/Function.h" |
| #include "llvm/IR/InstrTypes.h" |
| #include "llvm/IR/Instruction.h" |
| #include "llvm/IR/Instructions.h" |
| #include "llvm/IR/IntrinsicInst.h" |
| #include "llvm/IR/LLVMContext.h" |
| #include "llvm/IR/Metadata.h" |
| #include "llvm/IR/Module.h" |
| #include "llvm/IR/PredIteratorCache.h" |
| #include "llvm/IR/Type.h" |
| #include "llvm/IR/Use.h" |
| #include "llvm/IR/User.h" |
| #include "llvm/IR/Value.h" |
| #include "llvm/InitializePasses.h" |
| #include "llvm/Pass.h" |
| #include "llvm/Support/AtomicOrdering.h" |
| #include "llvm/Support/Casting.h" |
| #include "llvm/Support/CommandLine.h" |
| #include "llvm/Support/Compiler.h" |
| #include "llvm/Support/Debug.h" |
| #include "llvm/Support/MathExtras.h" |
| #include <algorithm> |
| #include <cassert> |
| #include <cstdint> |
| #include <iterator> |
| #include <utility> |
| |
| using namespace llvm; |
| |
| #define DEBUG_TYPE "memdep" |
| |
| STATISTIC(NumCacheNonLocal, "Number of fully cached non-local responses"); |
| STATISTIC(NumCacheDirtyNonLocal, "Number of dirty cached non-local responses"); |
| STATISTIC(NumUncacheNonLocal, "Number of uncached non-local responses"); |
| |
| STATISTIC(NumCacheNonLocalPtr, |
| "Number of fully cached non-local ptr responses"); |
| STATISTIC(NumCacheDirtyNonLocalPtr, |
| "Number of cached, but dirty, non-local ptr responses"); |
| STATISTIC(NumUncacheNonLocalPtr, "Number of uncached non-local ptr responses"); |
| STATISTIC(NumCacheCompleteNonLocalPtr, |
| "Number of block queries that were completely cached"); |
| |
| // Limit for the number of instructions to scan in a block. |
| |
| static cl::opt<unsigned> BlockScanLimit( |
| "memdep-block-scan-limit", cl::Hidden, cl::init(100), |
| cl::desc("The number of instructions to scan in a block in memory " |
| "dependency analysis (default = 100)")); |
| |
| static cl::opt<unsigned> |
| BlockNumberLimit("memdep-block-number-limit", cl::Hidden, cl::init(1000), |
| cl::desc("The number of blocks to scan during memory " |
| "dependency analysis (default = 1000)")); |
| |
| // Limit on the number of memdep results to process. |
| static const unsigned int NumResultsLimit = 100; |
| |
| /// This is a helper function that removes Val from 'Inst's set in ReverseMap. |
| /// |
| /// If the set becomes empty, remove Inst's entry. |
| template <typename KeyTy> |
| static void |
| RemoveFromReverseMap(DenseMap<Instruction *, SmallPtrSet<KeyTy, 4>> &ReverseMap, |
| Instruction *Inst, KeyTy Val) { |
| typename DenseMap<Instruction *, SmallPtrSet<KeyTy, 4>>::iterator InstIt = |
| ReverseMap.find(Inst); |
| assert(InstIt != ReverseMap.end() && "Reverse map out of sync?"); |
| bool Found = InstIt->second.erase(Val); |
| assert(Found && "Invalid reverse map!"); |
| (void)Found; |
| if (InstIt->second.empty()) |
| ReverseMap.erase(InstIt); |
| } |
| |
| /// If the given instruction references a specific memory location, fill in Loc |
| /// with the details, otherwise set Loc.Ptr to null. |
| /// |
| /// Returns a ModRefInfo value describing the general behavior of the |
| /// instruction. |
| static ModRefInfo GetLocation(const Instruction *Inst, MemoryLocation &Loc, |
| const TargetLibraryInfo &TLI) { |
| if (const LoadInst *LI = dyn_cast<LoadInst>(Inst)) { |
| if (LI->isUnordered()) { |
| Loc = MemoryLocation::get(LI); |
| return ModRefInfo::Ref; |
| } |
| if (LI->getOrdering() == AtomicOrdering::Monotonic) { |
| Loc = MemoryLocation::get(LI); |
| return ModRefInfo::ModRef; |
| } |
| Loc = MemoryLocation(); |
| return ModRefInfo::ModRef; |
| } |
| |
| if (const StoreInst *SI = dyn_cast<StoreInst>(Inst)) { |
| if (SI->isUnordered()) { |
| Loc = MemoryLocation::get(SI); |
| return ModRefInfo::Mod; |
| } |
| if (SI->getOrdering() == AtomicOrdering::Monotonic) { |
| Loc = MemoryLocation::get(SI); |
| return ModRefInfo::ModRef; |
| } |
| Loc = MemoryLocation(); |
| return ModRefInfo::ModRef; |
| } |
| |
| if (const VAArgInst *V = dyn_cast<VAArgInst>(Inst)) { |
| Loc = MemoryLocation::get(V); |
| return ModRefInfo::ModRef; |
| } |
| |
| if (const CallInst *CI = isFreeCall(Inst, &TLI)) { |
| // calls to free() deallocate the entire structure |
| Loc = MemoryLocation::getAfter(CI->getArgOperand(0)); |
| return ModRefInfo::Mod; |
| } |
| |
| if (const IntrinsicInst *II = dyn_cast<IntrinsicInst>(Inst)) { |
| switch (II->getIntrinsicID()) { |
| case Intrinsic::lifetime_start: |
| case Intrinsic::lifetime_end: |
| case Intrinsic::invariant_start: |
| Loc = MemoryLocation::getForArgument(II, 1, TLI); |
| // These intrinsics don't really modify the memory, but returning Mod |
| // will allow them to be handled conservatively. |
| return ModRefInfo::Mod; |
| case Intrinsic::invariant_end: |
| Loc = MemoryLocation::getForArgument(II, 2, TLI); |
| // These intrinsics don't really modify the memory, but returning Mod |
| // will allow them to be handled conservatively. |
| return ModRefInfo::Mod; |
| case Intrinsic::masked_load: |
| Loc = MemoryLocation::getForArgument(II, 0, TLI); |
| return ModRefInfo::Ref; |
| case Intrinsic::masked_store: |
| Loc = MemoryLocation::getForArgument(II, 1, TLI); |
| return ModRefInfo::Mod; |
| default: |
| break; |
| } |
| } |
| |
| // Otherwise, just do the coarse-grained thing that always works. |
| if (Inst->mayWriteToMemory()) |
| return ModRefInfo::ModRef; |
| if (Inst->mayReadFromMemory()) |
| return ModRefInfo::Ref; |
| return ModRefInfo::NoModRef; |
| } |
| |
| /// Private helper for finding the local dependencies of a call site. |
| MemDepResult MemoryDependenceResults::getCallDependencyFrom( |
| CallBase *Call, bool isReadOnlyCall, BasicBlock::iterator ScanIt, |
| BasicBlock *BB) { |
| unsigned Limit = getDefaultBlockScanLimit(); |
| |
| // Walk backwards through the block, looking for dependencies. |
| while (ScanIt != BB->begin()) { |
| Instruction *Inst = &*--ScanIt; |
| // Debug intrinsics don't cause dependences and should not affect Limit |
| if (isa<DbgInfoIntrinsic>(Inst)) |
| continue; |
| |
| // Limit the amount of scanning we do so we don't end up with quadratic |
| // running time on extreme testcases. |
| --Limit; |
| if (!Limit) |
| return MemDepResult::getUnknown(); |
| |
| // If this inst is a memory op, get the pointer it accessed |
| MemoryLocation Loc; |
| ModRefInfo MR = GetLocation(Inst, Loc, TLI); |
| if (Loc.Ptr) { |
| // A simple instruction. |
| if (isModOrRefSet(AA.getModRefInfo(Call, Loc))) |
| return MemDepResult::getClobber(Inst); |
| continue; |
| } |
| |
| if (auto *CallB = dyn_cast<CallBase>(Inst)) { |
| // If these two calls do not interfere, look past it. |
| if (isNoModRef(AA.getModRefInfo(Call, CallB))) { |
| // If the two calls are the same, return Inst as a Def, so that |
| // Call can be found redundant and eliminated. |
| if (isReadOnlyCall && !isModSet(MR) && |
| Call->isIdenticalToWhenDefined(CallB)) |
| return MemDepResult::getDef(Inst); |
| |
| // Otherwise if the two calls don't interact (e.g. CallB is readnone) |
| // keep scanning. |
| continue; |
| } else |
| 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 (isModOrRefSet(MR)) |
| 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()) |
| return MemDepResult::getNonLocal(); |
| return MemDepResult::getNonFuncLocal(); |
| } |
| |
| MemDepResult MemoryDependenceResults::getPointerDependencyFrom( |
| const MemoryLocation &MemLoc, bool isLoad, BasicBlock::iterator ScanIt, |
| BasicBlock *BB, Instruction *QueryInst, unsigned *Limit, |
| BatchAAResults &BatchAA) { |
| MemDepResult InvariantGroupDependency = MemDepResult::getUnknown(); |
| if (QueryInst != nullptr) { |
| if (auto *LI = dyn_cast<LoadInst>(QueryInst)) { |
| InvariantGroupDependency = getInvariantGroupPointerDependency(LI, BB); |
| |
| if (InvariantGroupDependency.isDef()) |
| return InvariantGroupDependency; |
| } |
| } |
| MemDepResult SimpleDep = getSimplePointerDependencyFrom( |
| MemLoc, isLoad, ScanIt, BB, QueryInst, Limit, BatchAA); |
| if (SimpleDep.isDef()) |
| return SimpleDep; |
| // Non-local invariant group dependency indicates there is non local Def |
| // (it only returns nonLocal if it finds nonLocal def), which is better than |
| // local clobber and everything else. |
| if (InvariantGroupDependency.isNonLocal()) |
| return InvariantGroupDependency; |
| |
| assert(InvariantGroupDependency.isUnknown() && |
| "InvariantGroupDependency should be only unknown at this point"); |
| return SimpleDep; |
| } |
| |
| MemDepResult MemoryDependenceResults::getPointerDependencyFrom( |
| const MemoryLocation &MemLoc, bool isLoad, BasicBlock::iterator ScanIt, |
| BasicBlock *BB, Instruction *QueryInst, unsigned *Limit) { |
| BatchAAResults BatchAA(AA); |
| return getPointerDependencyFrom(MemLoc, isLoad, ScanIt, BB, QueryInst, Limit, |
| BatchAA); |
| } |
| |
| MemDepResult |
| MemoryDependenceResults::getInvariantGroupPointerDependency(LoadInst *LI, |
| BasicBlock *BB) { |
| |
| if (!LI->hasMetadata(LLVMContext::MD_invariant_group)) |
| return MemDepResult::getUnknown(); |
| |
| // Take the ptr operand after all casts and geps 0. This way we can search |
| // cast graph down only. |
| Value *LoadOperand = LI->getPointerOperand()->stripPointerCasts(); |
| |
| // It's is not safe to walk the use list of global value, because function |
| // passes aren't allowed to look outside their functions. |
| // FIXME: this could be fixed by filtering instructions from outside |
| // of current function. |
| if (isa<GlobalValue>(LoadOperand)) |
| return MemDepResult::getUnknown(); |
| |
| // Queue to process all pointers that are equivalent to load operand. |
| SmallVector<const Value *, 8> LoadOperandsQueue; |
| LoadOperandsQueue.push_back(LoadOperand); |
| |
| Instruction *ClosestDependency = nullptr; |
| // Order of instructions in uses list is unpredictible. In order to always |
| // get the same result, we will look for the closest dominance. |
| auto GetClosestDependency = [this](Instruction *Best, Instruction *Other) { |
| assert(Other && "Must call it with not null instruction"); |
| if (Best == nullptr || DT.dominates(Best, Other)) |
| return Other; |
| return Best; |
| }; |
| |
| // FIXME: This loop is O(N^2) because dominates can be O(n) and in worst case |
| // we will see all the instructions. This should be fixed in MSSA. |
| while (!LoadOperandsQueue.empty()) { |
| const Value *Ptr = LoadOperandsQueue.pop_back_val(); |
| assert(Ptr && !isa<GlobalValue>(Ptr) && |
| "Null or GlobalValue should not be inserted"); |
| |
| for (const Use &Us : Ptr->uses()) { |
| auto *U = dyn_cast<Instruction>(Us.getUser()); |
| if (!U || U == LI || !DT.dominates(U, LI)) |
| continue; |
| |
| // Bitcast or gep with zeros are using Ptr. Add to queue to check it's |
| // users. U = bitcast Ptr |
| if (isa<BitCastInst>(U)) { |
| LoadOperandsQueue.push_back(U); |
| continue; |
| } |
| // Gep with zeros is equivalent to bitcast. |
| // FIXME: we are not sure if some bitcast should be canonicalized to gep 0 |
| // or gep 0 to bitcast because of SROA, so there are 2 forms. When |
| // typeless pointers will be ready then both cases will be gone |
| // (and this BFS also won't be needed). |
| if (auto *GEP = dyn_cast<GetElementPtrInst>(U)) |
| if (GEP->hasAllZeroIndices()) { |
| LoadOperandsQueue.push_back(U); |
| continue; |
| } |
| |
| // If we hit load/store with the same invariant.group metadata (and the |
| // same pointer operand) we can assume that value pointed by pointer |
| // operand didn't change. |
| if ((isa<LoadInst>(U) || |
| (isa<StoreInst>(U) && |
| cast<StoreInst>(U)->getPointerOperand() == Ptr)) && |
| U->hasMetadata(LLVMContext::MD_invariant_group)) |
| ClosestDependency = GetClosestDependency(ClosestDependency, U); |
| } |
| } |
| |
| if (!ClosestDependency) |
| return MemDepResult::getUnknown(); |
| if (ClosestDependency->getParent() == BB) |
| return MemDepResult::getDef(ClosestDependency); |
| // Def(U) can't be returned here because it is non-local. If local |
| // dependency won't be found then return nonLocal counting that the |
| // user will call getNonLocalPointerDependency, which will return cached |
| // result. |
| NonLocalDefsCache.try_emplace( |
| LI, NonLocalDepResult(ClosestDependency->getParent(), |
| MemDepResult::getDef(ClosestDependency), nullptr)); |
| ReverseNonLocalDefsCache[ClosestDependency].insert(LI); |
| return MemDepResult::getNonLocal(); |
| } |
| |
| MemDepResult MemoryDependenceResults::getSimplePointerDependencyFrom( |
| const MemoryLocation &MemLoc, bool isLoad, BasicBlock::iterator ScanIt, |
| BasicBlock *BB, Instruction *QueryInst, unsigned *Limit, |
| BatchAAResults &BatchAA) { |
| bool isInvariantLoad = false; |
| |
| unsigned DefaultLimit = getDefaultBlockScanLimit(); |
| if (!Limit) |
| Limit = &DefaultLimit; |
| |
| // We must be careful with atomic accesses, as they may allow another thread |
| // to touch this location, clobbering it. We are conservative: if the |
| // QueryInst is not a simple (non-atomic) memory access, we automatically |
| // return getClobber. |
| // If it is simple, we know based on the results of |
| // "Compiler testing via a theory of sound optimisations in the C11/C++11 |
| // memory model" in PLDI 2013, that a non-atomic location can only be |
| // clobbered between a pair of a release and an acquire action, with no |
| // access to the location in between. |
| // Here is an example for giving the general intuition behind this rule. |
| // In the following code: |
| // store x 0; |
| // release action; [1] |
| // acquire action; [4] |
| // %val = load x; |
| // It is unsafe to replace %val by 0 because another thread may be running: |
| // acquire action; [2] |
| // store x 42; |
| // release action; [3] |
| // with synchronization from 1 to 2 and from 3 to 4, resulting in %val |
| // being 42. A key property of this program however is that if either |
| // 1 or 4 were missing, there would be a race between the store of 42 |
| // either the store of 0 or the load (making the whole program racy). |
| // The paper mentioned above shows that the same property is respected |
| // by every program that can detect any optimization of that kind: either |
| // it is racy (undefined) or there is a release followed by an acquire |
| // between the pair of accesses under consideration. |
| |
| // If the load is invariant, we "know" that it doesn't alias *any* write. We |
| // do want to respect mustalias results since defs are useful for value |
| // forwarding, but any mayalias write can be assumed to be noalias. |
| // Arguably, this logic should be pushed inside AliasAnalysis itself. |
| if (isLoad && QueryInst) { |
| LoadInst *LI = dyn_cast<LoadInst>(QueryInst); |
| if (LI && LI->hasMetadata(LLVMContext::MD_invariant_load)) |
| isInvariantLoad = true; |
| } |
| |
| // Return "true" if and only if the instruction I is either a non-simple |
| // load or a non-simple store. |
| auto isNonSimpleLoadOrStore = [](Instruction *I) -> bool { |
| if (auto *LI = dyn_cast<LoadInst>(I)) |
| return !LI->isSimple(); |
| if (auto *SI = dyn_cast<StoreInst>(I)) |
| return !SI->isSimple(); |
| return false; |
| }; |
| |
| // Return "true" if I is not a load and not a store, but it does access |
| // memory. |
| auto isOtherMemAccess = [](Instruction *I) -> bool { |
| return !isa<LoadInst>(I) && !isa<StoreInst>(I) && I->mayReadOrWriteMemory(); |
| }; |
| |
| // Walk backwards through the basic block, looking for dependencies. |
| while (ScanIt != BB->begin()) { |
| Instruction *Inst = &*--ScanIt; |
| |
| if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(Inst)) |
| // Debug intrinsics don't (and can't) cause dependencies. |
| if (isa<DbgInfoIntrinsic>(II)) |
| continue; |
| |
| // Limit the amount of scanning we do so we don't end up with quadratic |
| // running time on extreme testcases. |
| --*Limit; |
| if (!*Limit) |
| return MemDepResult::getUnknown(); |
| |
| if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(Inst)) { |
| // If we reach a lifetime begin or end marker, then the query ends here |
| // because the value is undefined. |
| Intrinsic::ID ID = II->getIntrinsicID(); |
| switch (ID) { |
| case Intrinsic::lifetime_start: { |
| // FIXME: This only considers queries directly on the invariant-tagged |
| // pointer, not on query pointers that are indexed off of them. It'd |
| // be nice to handle that at some point (the right approach is to use |
| // GetPointerBaseWithConstantOffset). |
| MemoryLocation ArgLoc = MemoryLocation::getAfter(II->getArgOperand(1)); |
| if (BatchAA.isMustAlias(ArgLoc, MemLoc)) |
| return MemDepResult::getDef(II); |
| continue; |
| } |
| case Intrinsic::masked_load: |
| case Intrinsic::masked_store: { |
| MemoryLocation Loc; |
| /*ModRefInfo MR =*/ GetLocation(II, Loc, TLI); |
| AliasResult R = BatchAA.alias(Loc, MemLoc); |
| if (R == AliasResult::NoAlias) |
| continue; |
| if (R == AliasResult::MustAlias) |
| return MemDepResult::getDef(II); |
| if (ID == Intrinsic::masked_load) |
| continue; |
| return MemDepResult::getClobber(II); |
| } |
| } |
| } |
| |
| // Values depend on loads if the pointers are must aliased. This means |
| // that a load depends on another must aliased load from the same value. |
| // One exception is atomic loads: a value can depend on an atomic load that |
| // it does not alias with when this atomic load indicates that another |
| // thread may be accessing the location. |
| if (LoadInst *LI = dyn_cast<LoadInst>(Inst)) { |
| // While volatile access cannot be eliminated, they do not have to clobber |
| // non-aliasing locations, as normal accesses, for example, can be safely |
| // reordered with volatile accesses. |
| if (LI->isVolatile()) { |
| if (!QueryInst) |
| // Original QueryInst *may* be volatile |
| return MemDepResult::getClobber(LI); |
| if (QueryInst->isVolatile()) |
| // Ordering required if QueryInst is itself volatile |
| return MemDepResult::getClobber(LI); |
| // Otherwise, volatile doesn't imply any special ordering |
| } |
| |
| // Atomic loads have complications involved. |
| // A Monotonic (or higher) load is OK if the query inst is itself not |
| // atomic. |
| // FIXME: This is overly conservative. |
| if (LI->isAtomic() && isStrongerThanUnordered(LI->getOrdering())) { |
| if (!QueryInst || isNonSimpleLoadOrStore(QueryInst) || |
| isOtherMemAccess(QueryInst)) |
| return MemDepResult::getClobber(LI); |
| if (LI->getOrdering() != AtomicOrdering::Monotonic) |
| return MemDepResult::getClobber(LI); |
| } |
| |
| MemoryLocation LoadLoc = MemoryLocation::get(LI); |
| |
| // If we found a pointer, check if it could be the same as our pointer. |
| AliasResult R = BatchAA.alias(LoadLoc, MemLoc); |
| |
| if (isLoad) { |
| if (R == AliasResult::NoAlias) |
| continue; |
| |
| // Must aliased loads are defs of each other. |
| if (R == AliasResult::MustAlias) |
| return MemDepResult::getDef(Inst); |
| |
| // If we have a partial alias, then return this as a clobber for the |
| // client to handle. |
| if (R == AliasResult::PartialAlias && R.hasOffset()) { |
| ClobberOffsets[LI] = R.getOffset(); |
| return MemDepResult::getClobber(Inst); |
| } |
| |
| // Random may-alias loads don't depend on each other without a |
| // dependence. |
| continue; |
| } |
| |
| // Stores don't depend on other no-aliased accesses. |
| if (R == AliasResult::NoAlias) |
| continue; |
| |
| // Stores don't alias loads from read-only memory. |
| if (BatchAA.pointsToConstantMemory(LoadLoc)) |
| continue; |
| |
| // Stores depend on may/must aliased loads. |
| return MemDepResult::getDef(Inst); |
| } |
| |
| if (StoreInst *SI = dyn_cast<StoreInst>(Inst)) { |
| // Atomic stores have complications involved. |
| // A Monotonic store is OK if the query inst is itself not atomic. |
| // FIXME: This is overly conservative. |
| if (!SI->isUnordered() && SI->isAtomic()) { |
| if (!QueryInst || isNonSimpleLoadOrStore(QueryInst) || |
| isOtherMemAccess(QueryInst)) |
| return MemDepResult::getClobber(SI); |
| if (SI->getOrdering() != AtomicOrdering::Monotonic) |
| return MemDepResult::getClobber(SI); |
| } |
| |
| // FIXME: this is overly conservative. |
| // While volatile access cannot be eliminated, they do not have to clobber |
| // non-aliasing locations, as normal accesses can for example be reordered |
| // with volatile accesses. |
| if (SI->isVolatile()) |
| if (!QueryInst || isNonSimpleLoadOrStore(QueryInst) || |
| isOtherMemAccess(QueryInst)) |
| return MemDepResult::getClobber(SI); |
| |
| // If alias analysis can tell that this store is guaranteed to not modify |
| // the query pointer, ignore it. Use getModRefInfo to handle cases where |
| // the query pointer points to constant memory etc. |
| if (!isModOrRefSet(BatchAA.getModRefInfo(SI, MemLoc))) |
| continue; |
| |
| // 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. |
| // FIXME: Use ModRefInfo::Must bit from getModRefInfo call above. |
| MemoryLocation StoreLoc = MemoryLocation::get(SI); |
| |
| // If we found a pointer, check if it could be the same as our pointer. |
| AliasResult R = BatchAA.alias(StoreLoc, MemLoc); |
| |
| if (R == AliasResult::NoAlias) |
| continue; |
| if (R == AliasResult::MustAlias) |
| return MemDepResult::getDef(Inst); |
| if (isInvariantLoad) |
| continue; |
| return MemDepResult::getClobber(Inst); |
| } |
| |
| // If this is an allocation, and if we know that the accessed pointer is to |
| // the allocation, return Def. This means that there is no dependence and |
| // the access can be optimized based on that. For example, a load could |
| // turn into undef. Note that we can bypass the allocation itself when |
| // looking for a clobber in many cases; that's an alias property and is |
| // handled by BasicAA. |
| if (isa<AllocaInst>(Inst) || isNoAliasFn(Inst, &TLI)) { |
| const Value *AccessPtr = getUnderlyingObject(MemLoc.Ptr); |
| if (AccessPtr == Inst || BatchAA.isMustAlias(Inst, AccessPtr)) |
| return MemDepResult::getDef(Inst); |
| } |
| |
| if (isInvariantLoad) |
| continue; |
| |
| // A release fence requires that all stores complete before it, but does |
| // not prevent the reordering of following loads or stores 'before' the |
| // fence. As a result, we look past it when finding a dependency for |
| // loads. DSE uses this to find preceding stores to delete and thus we |
| // can't bypass the fence if the query instruction is a store. |
| if (FenceInst *FI = dyn_cast<FenceInst>(Inst)) |
| if (isLoad && FI->getOrdering() == AtomicOrdering::Release) |
| continue; |
| |
| // See if this instruction (e.g. a call or vaarg) mod/ref's the pointer. |
| ModRefInfo MR = BatchAA.getModRefInfo(Inst, MemLoc); |
| // If necessary, perform additional analysis. |
| if (isModAndRefSet(MR)) |
| MR = BatchAA.callCapturesBefore(Inst, MemLoc, &DT); |
| switch (clearMust(MR)) { |
| case ModRefInfo::NoModRef: |
| // If the call has no effect on the queried pointer, just ignore it. |
| continue; |
| case ModRefInfo::Mod: |
| return MemDepResult::getClobber(Inst); |
| case ModRefInfo::Ref: |
| // If the call is known to never store to the pointer, and if this is a |
| // load query, we can safely ignore it (scan past it). |
| if (isLoad) |
| continue; |
| LLVM_FALLTHROUGH; |
| default: |
| // Otherwise, there is a potential dependence. Return a clobber. |
| 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()) |
| return MemDepResult::getNonLocal(); |
| return MemDepResult::getNonFuncLocal(); |
| } |
| |
| MemDepResult MemoryDependenceResults::getDependency(Instruction *QueryInst) { |
| ClobberOffsets.clear(); |
| 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 |
| // unknown, otherwise it is non-local. |
| if (QueryParent != &QueryParent->getParent()->getEntryBlock()) |
| LocalCache = MemDepResult::getNonLocal(); |
| else |
| LocalCache = MemDepResult::getNonFuncLocal(); |
| } else { |
| MemoryLocation MemLoc; |
| ModRefInfo MR = GetLocation(QueryInst, MemLoc, TLI); |
| if (MemLoc.Ptr) { |
| // If we can do a pointer scan, make it happen. |
| bool isLoad = !isModSet(MR); |
| if (auto *II = dyn_cast<IntrinsicInst>(QueryInst)) |
| isLoad |= II->getIntrinsicID() == Intrinsic::lifetime_start; |
| |
| LocalCache = |
| getPointerDependencyFrom(MemLoc, isLoad, ScanPos->getIterator(), |
| QueryParent, QueryInst, nullptr); |
| } else if (auto *QueryCall = dyn_cast<CallBase>(QueryInst)) { |
| bool isReadOnly = AA.onlyReadsMemory(QueryCall); |
| LocalCache = getCallDependencyFrom(QueryCall, isReadOnly, |
| ScanPos->getIterator(), QueryParent); |
| } else |
| // Non-memory instruction. |
| LocalCache = MemDepResult::getUnknown(); |
| } |
| |
| // Remember the result! |
| if (Instruction *I = LocalCache.getInst()) |
| ReverseLocalDeps[I].insert(QueryInst); |
| |
| return LocalCache; |
| } |
| |
| #ifndef NDEBUG |
| /// This method is used when -debug is specified to verify that cache arrays |
| /// are properly kept sorted. |
| static void AssertSorted(MemoryDependenceResults::NonLocalDepInfo &Cache, |
| int Count = -1) { |
| if (Count == -1) |
| Count = Cache.size(); |
| assert(std::is_sorted(Cache.begin(), Cache.begin() + Count) && |
| "Cache isn't sorted!"); |
| } |
| #endif |
| |
| const MemoryDependenceResults::NonLocalDepInfo & |
| MemoryDependenceResults::getNonLocalCallDependency(CallBase *QueryCall) { |
| assert(getDependency(QueryCall).isNonLocal() && |
| "getNonLocalCallDependency should only be used on calls with " |
| "non-local deps!"); |
| PerInstNLInfo &CacheP = NonLocalDepsMap[QueryCall]; |
| NonLocalDepInfo &Cache = CacheP.first; |
| |
| // This is the set of blocks that need to be recomputed. In the cached case, |
| // this can happen due to instructions being deleted etc. In the uncached |
| // case, this starts out as the set of predecessors we care about. |
| SmallVector<BasicBlock *, 32> DirtyBlocks; |
| |
| if (!Cache.empty()) { |
| // Okay, we have a cache entry. If we know it is not dirty, just return it |
| // with no computation. |
| if (!CacheP.second) { |
| ++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 (auto &Entry : Cache) |
| if (Entry.getResult().isDirty()) |
| DirtyBlocks.push_back(Entry.getBB()); |
| |
| // Sort the cache so that we can do fast binary search lookups below. |
| llvm::sort(Cache); |
| |
| ++NumCacheDirtyNonLocal; |
| // cerr << "CACHED CASE: " << DirtyBlocks.size() << " dirty: " |
| // << Cache.size() << " cached: " << *QueryInst; |
| } else { |
| // Seed DirtyBlocks with each of the preds of QueryInst's block. |
| BasicBlock *QueryBB = QueryCall->getParent(); |
| append_range(DirtyBlocks, PredCache.get(QueryBB)); |
| ++NumUncacheNonLocal; |
| } |
| |
| // isReadonlyCall - If this is a read-only call, we can be more aggressive. |
| bool isReadonlyCall = AA.onlyReadsMemory(QueryCall); |
| |
| SmallPtrSet<BasicBlock *, 32> Visited; |
| |
| unsigned NumSortedEntries = Cache.size(); |
| LLVM_DEBUG(AssertSorted(Cache)); |
| |
| // Iterate while we still have blocks to update. |
| while (!DirtyBlocks.empty()) { |
| BasicBlock *DirtyBB = DirtyBlocks.pop_back_val(); |
| |
| // Already processed this block? |
| if (!Visited.insert(DirtyBB).second) |
| continue; |
| |
| // Do a binary search to see if we already have an entry for this block in |
| // the cache set. If so, find it. |
| LLVM_DEBUG(AssertSorted(Cache, NumSortedEntries)); |
| NonLocalDepInfo::iterator Entry = |
| std::upper_bound(Cache.begin(), Cache.begin() + NumSortedEntries, |
| NonLocalDepEntry(DirtyBB)); |
| if (Entry != Cache.begin() && std::prev(Entry)->getBB() == DirtyBB) |
| --Entry; |
| |
| NonLocalDepEntry *ExistingResult = nullptr; |
| 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(); |
| if (ExistingResult) { |
| if (Instruction *Inst = ExistingResult->getResult().getInst()) { |
| ScanPos = Inst->getIterator(); |
| // We're removing QueryInst's use of Inst. |
| RemoveFromReverseMap<Instruction *>(ReverseNonLocalDeps, Inst, |
| QueryCall); |
| } |
| } |
| |
| // Find out if this block has a local dependency for QueryInst. |
| MemDepResult Dep; |
| |
| if (ScanPos != DirtyBB->begin()) { |
| Dep = getCallDependencyFrom(QueryCall, isReadonlyCall, ScanPos, DirtyBB); |
| } else if (DirtyBB != &DirtyBB->getParent()->getEntryBlock()) { |
| // No dependence found. If this is the entry block of the function, it is |
| // a clobber, otherwise it is unknown. |
| Dep = MemDepResult::getNonLocal(); |
| } 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()) { |
| // Keep the ReverseNonLocalDeps map up to date so we can efficiently |
| // update this when we remove instructions. |
| if (Instruction *Inst = Dep.getInst()) |
| ReverseNonLocalDeps[Inst].insert(QueryCall); |
| } else { |
| |
| // If the block *is* completely transparent to the load, we need to check |
| // the predecessors of this block. Add them to our worklist. |
| append_range(DirtyBlocks, PredCache.get(DirtyBB)); |
| } |
| } |
| |
| return Cache; |
| } |
| |
| void MemoryDependenceResults::getNonLocalPointerDependency( |
| Instruction *QueryInst, SmallVectorImpl<NonLocalDepResult> &Result) { |
| const MemoryLocation Loc = MemoryLocation::get(QueryInst); |
| bool isLoad = isa<LoadInst>(QueryInst); |
| BasicBlock *FromBB = QueryInst->getParent(); |
| assert(FromBB); |
| |
| assert(Loc.Ptr->getType()->isPointerTy() && |
| "Can't get pointer deps of a non-pointer!"); |
| Result.clear(); |
| { |
| // Check if there is cached Def with invariant.group. |
| auto NonLocalDefIt = NonLocalDefsCache.find(QueryInst); |
| if (NonLocalDefIt != NonLocalDefsCache.end()) { |
| Result.push_back(NonLocalDefIt->second); |
| ReverseNonLocalDefsCache[NonLocalDefIt->second.getResult().getInst()] |
| .erase(QueryInst); |
| NonLocalDefsCache.erase(NonLocalDefIt); |
| return; |
| } |
| } |
| // This routine does not expect to deal with volatile instructions. |
| // Doing so would require piping through the QueryInst all the way through. |
| // TODO: volatiles can't be elided, but they can be reordered with other |
| // non-volatile accesses. |
| |
| // We currently give up on any instruction which is ordered, but we do handle |
| // atomic instructions which are unordered. |
| // TODO: Handle ordered instructions |
| auto isOrdered = [](Instruction *Inst) { |
| if (LoadInst *LI = dyn_cast<LoadInst>(Inst)) { |
| return !LI->isUnordered(); |
| } else if (StoreInst *SI = dyn_cast<StoreInst>(Inst)) { |
| return !SI->isUnordered(); |
| } |
| return false; |
| }; |
| if (QueryInst->isVolatile() || isOrdered(QueryInst)) { |
| Result.push_back(NonLocalDepResult(FromBB, MemDepResult::getUnknown(), |
| const_cast<Value *>(Loc.Ptr))); |
| return; |
| } |
| const DataLayout &DL = FromBB->getModule()->getDataLayout(); |
| PHITransAddr Address(const_cast<Value *>(Loc.Ptr), DL, &AC); |
| |
| // 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 |
| // translation. |
| DenseMap<BasicBlock *, Value *> Visited; |
| if (getNonLocalPointerDepFromBB(QueryInst, Address, Loc, isLoad, FromBB, |
| Result, Visited, true)) |
| return; |
| Result.clear(); |
| Result.push_back(NonLocalDepResult(FromBB, MemDepResult::getUnknown(), |
| const_cast<Value *>(Loc.Ptr))); |
| } |
| |
| /// Compute the memdep value for BB with Pointer/PointeeSize using either |
| /// cached information in Cache or by doing a lookup (which may use dirty cache |
| /// info if available). |
| /// |
| /// If we do a lookup, add the result to the cache. |
| MemDepResult MemoryDependenceResults::getNonLocalInfoForBlock( |
| Instruction *QueryInst, const MemoryLocation &Loc, bool isLoad, |
| BasicBlock *BB, NonLocalDepInfo *Cache, unsigned NumSortedEntries, |
| BatchAAResults &BatchAA) { |
| |
| bool isInvariantLoad = false; |
| |
| if (LoadInst *LI = dyn_cast_or_null<LoadInst>(QueryInst)) |
| isInvariantLoad = LI->getMetadata(LLVMContext::MD_invariant_load); |
| |
| // 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 = std::upper_bound( |
| Cache->begin(), Cache->begin() + NumSortedEntries, NonLocalDepEntry(BB)); |
| if (Entry != Cache->begin() && (Entry - 1)->getBB() == BB) |
| --Entry; |
| |
| NonLocalDepEntry *ExistingResult = nullptr; |
| if (Entry != Cache->begin() + NumSortedEntries && Entry->getBB() == BB) |
| ExistingResult = &*Entry; |
| |
| // Use cached result for invariant load only if there is no dependency for non |
| // invariant load. In this case invariant load can not have any dependency as |
| // well. |
| if (ExistingResult && isInvariantLoad && |
| !ExistingResult->getResult().isNonFuncLocal()) |
| ExistingResult = nullptr; |
| |
| // 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. |
| BasicBlock::iterator ScanPos = BB->end(); |
| if (ExistingResult && ExistingResult->getResult().getInst()) { |
| assert(ExistingResult->getResult().getInst()->getParent() == BB && |
| "Instruction invalidated?"); |
| ++NumCacheDirtyNonLocalPtr; |
| ScanPos = ExistingResult->getResult().getInst()->getIterator(); |
| |
| // 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, |
| QueryInst, nullptr, BatchAA); |
| |
| // Don't cache results for invariant load. |
| if (isInvariantLoad) |
| return Dep; |
| |
| // 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(); |
| assert(Inst && "Didn't depend on anything?"); |
| ValueIsLoadPair CacheKey(Loc.Ptr, isLoad); |
| ReverseNonLocalPtrDeps[Inst].insert(CacheKey); |
| return Dep; |
| } |
| |
| /// Sort the 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 |
| SortNonLocalDepInfoCache(MemoryDependenceResults::NonLocalDepInfo &Cache, |
| unsigned NumSortedEntries) { |
| switch (Cache.size() - NumSortedEntries) { |
| case 0: |
| // done, no new entries. |
| break; |
| case 2: { |
| // Two new entries, insert the last one into place. |
| NonLocalDepEntry Val = Cache.back(); |
| Cache.pop_back(); |
| MemoryDependenceResults::NonLocalDepInfo::iterator Entry = |
| std::upper_bound(Cache.begin(), Cache.end() - 1, Val); |
| Cache.insert(Entry, Val); |
| LLVM_FALLTHROUGH; |
| } |
| case 1: |
| // One new entry, Just insert the new value at the appropriate position. |
| if (Cache.size() != 1) { |
| NonLocalDepEntry Val = Cache.back(); |
| Cache.pop_back(); |
| MemoryDependenceResults::NonLocalDepInfo::iterator Entry = |
| llvm::upper_bound(Cache, Val); |
| Cache.insert(Entry, Val); |
| } |
| break; |
| default: |
| // Added many values, do a full scale sort. |
| llvm::sort(Cache); |
| break; |
| } |
| } |
| |
| /// Perform a dependency query based on pointer/pointeesize starting at the end |
| /// of StartBB. |
| /// |
| /// Add any clobber/def results to the results vector and keep track of which |
| /// blocks are visited in 'Visited'. |
| /// |
| /// This has special behavior for the first block queries (when SkipFirstBlock |
| /// is true). In this special case, it ignores the contents of the specified |
| /// block and starts returning dependence info for its predecessors. |
| /// |
| /// This function returns true on success, or false to indicate that it could |
| /// not compute dependence information for some reason. This should be treated |
| /// as a clobber dependence on the first instruction in the predecessor block. |
| bool MemoryDependenceResults::getNonLocalPointerDepFromBB( |
| Instruction *QueryInst, const PHITransAddr &Pointer, |
| const MemoryLocation &Loc, bool isLoad, BasicBlock *StartBB, |
| SmallVectorImpl<NonLocalDepResult> &Result, |
| DenseMap<BasicBlock *, Value *> &Visited, bool SkipFirstBlock, |
| bool IsIncomplete) { |
| // Look up the cached info for Pointer. |
| ValueIsLoadPair CacheKey(Pointer.getAddr(), isLoad); |
| |
| // Set up a temporary NLPI value. If the map doesn't yet have an entry for |
| // CacheKey, this value will be inserted as the associated value. Otherwise, |
| // it'll be ignored, and we'll have to check to see if the cached size and |
| // aa tags are consistent with the current query. |
| NonLocalPointerInfo InitialNLPI; |
| InitialNLPI.Size = Loc.Size; |
| InitialNLPI.AATags = Loc.AATags; |
| |
| bool isInvariantLoad = false; |
| if (LoadInst *LI = dyn_cast_or_null<LoadInst>(QueryInst)) |
| isInvariantLoad = LI->getMetadata(LLVMContext::MD_invariant_load); |
| |
| // Get the NLPI for CacheKey, inserting one into the map if it doesn't |
| // already have one. |
| std::pair<CachedNonLocalPointerInfo::iterator, bool> Pair = |
| NonLocalPointerDeps.insert(std::make_pair(CacheKey, InitialNLPI)); |
| NonLocalPointerInfo *CacheInfo = &Pair.first->second; |
| |
| // If we already have a cache entry for this CacheKey, we may need to do some |
| // work to reconcile the cache entry and the current query. |
| // Invariant loads don't participate in caching. Thus no need to reconcile. |
| if (!isInvariantLoad && !Pair.second) { |
| if (CacheInfo->Size != Loc.Size) { |
| bool ThrowOutEverything; |
| if (CacheInfo->Size.hasValue() && Loc.Size.hasValue()) { |
| // FIXME: We may be able to do better in the face of results with mixed |
| // precision. We don't appear to get them in practice, though, so just |
| // be conservative. |
| ThrowOutEverything = |
| CacheInfo->Size.isPrecise() != Loc.Size.isPrecise() || |
| CacheInfo->Size.getValue() < Loc.Size.getValue(); |
| } else { |
| // For our purposes, unknown size > all others. |
| ThrowOutEverything = !Loc.Size.hasValue(); |
| } |
| |
| if (ThrowOutEverything) { |
| // The query's Size is greater than the cached one. Throw out the |
| // cached data and proceed with the query at the greater size. |
| CacheInfo->Pair = BBSkipFirstBlockPair(); |
| CacheInfo->Size = Loc.Size; |
| for (auto &Entry : CacheInfo->NonLocalDeps) |
| if (Instruction *Inst = Entry.getResult().getInst()) |
| RemoveFromReverseMap(ReverseNonLocalPtrDeps, Inst, CacheKey); |
| CacheInfo->NonLocalDeps.clear(); |
| // The cache is cleared (in the above line) so we will have lost |
| // information about blocks we have already visited. We therefore must |
| // assume that the cache information is incomplete. |
| IsIncomplete = true; |
| } else { |
| // This query's Size is less than the cached one. Conservatively restart |
| // the query using the greater size. |
| return getNonLocalPointerDepFromBB( |
| QueryInst, Pointer, Loc.getWithNewSize(CacheInfo->Size), isLoad, |
| StartBB, Result, Visited, SkipFirstBlock, IsIncomplete); |
| } |
| } |
| |
| // If the query's AATags are inconsistent with the cached one, |
| // conservatively throw out the cached data and restart the query with |
| // no tag if needed. |
| if (CacheInfo->AATags != Loc.AATags) { |
| if (CacheInfo->AATags) { |
| CacheInfo->Pair = BBSkipFirstBlockPair(); |
| CacheInfo->AATags = AAMDNodes(); |
| for (auto &Entry : CacheInfo->NonLocalDeps) |
| if (Instruction *Inst = Entry.getResult().getInst()) |
| RemoveFromReverseMap(ReverseNonLocalPtrDeps, Inst, CacheKey); |
| CacheInfo->NonLocalDeps.clear(); |
| // The cache is cleared (in the above line) so we will have lost |
| // information about blocks we have already visited. We therefore must |
| // assume that the cache information is incomplete. |
| IsIncomplete = true; |
| } |
| if (Loc.AATags) |
| return getNonLocalPointerDepFromBB( |
| QueryInst, Pointer, Loc.getWithoutAATags(), isLoad, StartBB, Result, |
| Visited, SkipFirstBlock, IsIncomplete); |
| } |
| } |
| |
| NonLocalDepInfo *Cache = &CacheInfo->NonLocalDeps; |
| |
| // If we have valid cached information for exactly the block we are |
| // investigating, just return it with no recomputation. |
| // Don't use cached information for invariant loads since it is valid for |
| // non-invariant loads only. |
| if (!IsIncomplete && !isInvariantLoad && |
| CacheInfo->Pair == BBSkipFirstBlockPair(StartBB, SkipFirstBlock)) { |
| // We have a fully cached result for this query then we can just return the |
| // cached results and populate the visited set. However, we have to verify |
| // that we don't already have conflicting results for these blocks. Check |
| // to ensure that if a block in the results set is in the visited set that |
| // it was for the same pointer query. |
| if (!Visited.empty()) { |
| for (auto &Entry : *Cache) { |
| DenseMap<BasicBlock *, Value *>::iterator VI = |
| Visited.find(Entry.getBB()); |
| if (VI == Visited.end() || VI->second == Pointer.getAddr()) |
| continue; |
| |
| // We have a pointer mismatch in a block. Just return false, 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 false; |
| } |
| } |
| |
| Value *Addr = Pointer.getAddr(); |
| for (auto &Entry : *Cache) { |
| Visited.insert(std::make_pair(Entry.getBB(), Addr)); |
| if (Entry.getResult().isNonLocal()) { |
| continue; |
| } |
| |
| if (DT.isReachableFromEntry(Entry.getBB())) { |
| Result.push_back( |
| NonLocalDepResult(Entry.getBB(), Entry.getResult(), Addr)); |
| } |
| } |
| ++NumCacheCompleteNonLocalPtr; |
| return true; |
| } |
| |
| // 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 and not explicitly indicated as |
| // incomplete, the result will be valid cache info, otherwise it isn't. |
| // |
| // Invariant loads don't affect cache in any way thus no need to update |
| // CacheInfo as well. |
| if (!isInvariantLoad) { |
| if (!IsIncomplete && Cache->empty()) |
| CacheInfo->Pair = BBSkipFirstBlockPair(StartBB, SkipFirstBlock); |
| else |
| CacheInfo->Pair = BBSkipFirstBlockPair(); |
| } |
| |
| SmallVector<BasicBlock *, 32> Worklist; |
| Worklist.push_back(StartBB); |
| |
| // PredList used inside loop. |
| SmallVector<std::pair<BasicBlock *, PHITransAddr>, 16> PredList; |
| |
| // Keep track of the entries that we know are sorted. Previously cached |
| // entries will all be sorted. The entries we add we only sort on demand (we |
| // don't insert every element into its sorted position). We know that we |
| // won't get any reuse from currently inserted values, because we don't |
| // revisit blocks after we insert info for them. |
| unsigned NumSortedEntries = Cache->size(); |
| unsigned WorklistEntries = BlockNumberLimit; |
| bool GotWorklistLimit = false; |
| LLVM_DEBUG(AssertSorted(*Cache)); |
| |
| BatchAAResults BatchAA(AA); |
| while (!Worklist.empty()) { |
| BasicBlock *BB = Worklist.pop_back_val(); |
| |
| // If we do process a large number of blocks it becomes very expensive and |
| // likely it isn't worth worrying about |
| if (Result.size() > NumResultsLimit) { |
| Worklist.clear(); |
| // Sort it now (if needed) so that recursive invocations of |
| // getNonLocalPointerDepFromBB and other routines that could reuse the |
| // cache value will only see properly sorted cache arrays. |
| if (Cache && NumSortedEntries != Cache->size()) { |
| SortNonLocalDepInfoCache(*Cache, NumSortedEntries); |
| } |
| // Since we bail out, 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(); |
| return false; |
| } |
| |
| // Skip the first block if we have it. |
| if (!SkipFirstBlock) { |
| // Analyze the dependency of *Pointer in FromBB. See if we already have |
| // been here. |
| assert(Visited.count(BB) && "Should check 'visited' before adding to WL"); |
| |
| // Get the dependency info for Pointer in BB. If we have cached |
| // information, we will use it, otherwise we compute it. |
| LLVM_DEBUG(AssertSorted(*Cache, NumSortedEntries)); |
| MemDepResult Dep = getNonLocalInfoForBlock( |
| QueryInst, Loc, isLoad, BB, Cache, NumSortedEntries, BatchAA); |
| |
| // If we got a Def or Clobber, add this to the list of results. |
| if (!Dep.isNonLocal()) { |
| 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 |
| // the same Pointer. |
| if (!Pointer.NeedsPHITranslationFromBlock(BB)) { |
| SkipFirstBlock = false; |
| SmallVector<BasicBlock *, 16> NewBlocks; |
| for (BasicBlock *Pred : PredCache.get(BB)) { |
| // Verify that we haven't looked at this block yet. |
| std::pair<DenseMap<BasicBlock *, Value *>::iterator, bool> InsertRes = |
| Visited.insert(std::make_pair(Pred, Pointer.getAddr())); |
| if (InsertRes.second) { |
| // First time we've looked at *PI. |
| NewBlocks.push_back(Pred); |
| 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. |
| if (InsertRes.first->second != Pointer.getAddr()) { |
| // Make sure to clean up the Visited map before continuing on to |
| // PredTranslationFailure. |
| for (unsigned i = 0; i < NewBlocks.size(); i++) |
| Visited.erase(NewBlocks[i]); |
| goto PredTranslationFailure; |
| } |
| } |
| if (NewBlocks.size() > WorklistEntries) { |
| // Make sure to clean up the Visited map before continuing on to |
| // PredTranslationFailure. |
| for (unsigned i = 0; i < NewBlocks.size(); i++) |
| Visited.erase(NewBlocks[i]); |
| GotWorklistLimit = true; |
| goto PredTranslationFailure; |
| } |
| WorklistEntries -= NewBlocks.size(); |
| 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 |
| // getNonLocalPointerDepFromBB and other routines that could reuse the cache |
| // value will only see properly sorted cache arrays. |
| if (Cache && NumSortedEntries != Cache->size()) { |
| SortNonLocalDepInfoCache(*Cache, NumSortedEntries); |
| NumSortedEntries = Cache->size(); |
| } |
| Cache = nullptr; |
| |
| PredList.clear(); |
| for (BasicBlock *Pred : PredCache.get(BB)) { |
| PredList.push_back(std::make_pair(Pred, Pointer)); |
| |
| // Get the PHI translated pointer in this predecessor. This can fail if |
| // not translatable, in which case the getAddr() returns null. |
| PHITransAddr &PredPointer = PredList.back().second; |
| PredPointer.PHITranslateValue(BB, Pred, &DT, /*MustDominate=*/false); |
| 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 |
| // the successor translates to a pointer value different than the |
| // pointer the block was first analyzed with. |
| std::pair<DenseMap<BasicBlock *, Value *>::iterator, bool> InsertRes = |
| Visited.insert(std::make_pair(Pred, PredPtrVal)); |
| |
| if (!InsertRes.second) { |
| // We found the pred; take it off the list of preds to visit. |
| PredList.pop_back(); |
| |
| // If the predecessor was visited with PredPtr, then we already did |
| // 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, n = PredList.size(); i < n; ++i) |
| Visited.erase(PredList[i].first); |
| |
| goto PredTranslationFailure; |
| } |
| } |
| |
| // 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 |
| // datastructures in ways the code after the PredTranslationFailure label |
| // doesn't expect.) |
| for (unsigned i = 0, n = PredList.size(); i < n; ++i) { |
| BasicBlock *Pred = PredList[i].first; |
| PHITransAddr &PredPointer = PredList[i].second; |
| Value *PredPtrVal = PredPointer.getAddr(); |
| |
| bool CanTranslate = true; |
| // If PHI translation was unable to find an available pointer in this |
| // predecessor, then we have to assume that the pointer is clobbered in |
| // that predecessor. We can still do PRE of the load, which would insert |
| // a computation of the pointer in this predecessor. |
| if (!PredPtrVal) |
| CanTranslate = false; |
| |
| // FIXME: it is entirely possible that PHI translating will end up with |
| // the same value. Consider PHI translating something like: |
| // X = phi [x, bb1], [y, bb2]. PHI translating for bb1 doesn't *need* |
| // to recurse here, pedantically speaking. |
| |
| // If getNonLocalPointerDepFromBB fails here, that means the cached |
| // result conflicted with the Visited list; we have to conservatively |
| // assume it is unknown, but this also does not block PRE of the load. |
| if (!CanTranslate || |
| !getNonLocalPointerDepFromBB(QueryInst, PredPointer, |
| Loc.getWithNewPtr(PredPtrVal), isLoad, |
| Pred, Result, Visited)) { |
| // Add the entry to the Result list. |
| NonLocalDepResult Entry(Pred, MemDepResult::getUnknown(), PredPtrVal); |
| Result.push_back(Entry); |
| |
| // Since we had a phi translation failure, the cache for CacheKey won't |
| // include all of the entries that we need to immediately satisfy future |
| // queries. Mark this in NonLocalPointerDeps by setting the |
| // BBSkipFirstBlockPair pointer to null. This requires reuse of the |
| // cached value to do more work but not miss the phi trans failure. |
| NonLocalPointerInfo &NLPI = NonLocalPointerDeps[CacheKey]; |
| NLPI.Pair = BBSkipFirstBlockPair(); |
| 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 |
| // results from the set" Clear out the indicator for this. |
| CacheInfo->Pair = BBSkipFirstBlockPair(); |
| SkipFirstBlock = false; |
| continue; |
| |
| PredTranslationFailure: |
| // 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) { |
| // 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 |
| // incoming value. Since we can't phi translate to one of the predecessors, |
| // we have to bail out. |
| if (SkipFirstBlock) |
| return false; |
| |
| // Results of invariant loads are not cached thus no need to update cached |
| // information. |
| if (!isInvariantLoad) { |
| for (NonLocalDepEntry &I : llvm::reverse(*Cache)) { |
| if (I.getBB() != BB) |
| continue; |
| |
| assert((GotWorklistLimit || I.getResult().isNonLocal() || |
| !DT.isReachableFromEntry(BB)) && |
| "Should only be here with transparent block"); |
| |
| I.setResult(MemDepResult::getUnknown()); |
| |
| |
| break; |
| } |
| } |
| (void)GotWorklistLimit; |
| // Go ahead and report unknown dependence. |
| Result.push_back( |
| NonLocalDepResult(BB, MemDepResult::getUnknown(), Pointer.getAddr())); |
| } |
| |
| // Okay, we're done now. If we added new values to the cache, re-sort it. |
| SortNonLocalDepInfoCache(*Cache, NumSortedEntries); |
| LLVM_DEBUG(AssertSorted(*Cache)); |
| return true; |
| } |
| |
| /// If P exists in CachedNonLocalPointerInfo or NonLocalDefsCache, remove it. |
| void MemoryDependenceResults::removeCachedNonLocalPointerDependencies( |
| ValueIsLoadPair P) { |
| |
| // Most of the time this cache is empty. |
| if (!NonLocalDefsCache.empty()) { |
| auto it = NonLocalDefsCache.find(P.getPointer()); |
| if (it != NonLocalDefsCache.end()) { |
| RemoveFromReverseMap(ReverseNonLocalDefsCache, |
| it->second.getResult().getInst(), P.getPointer()); |
| NonLocalDefsCache.erase(it); |
| } |
| |
| if (auto *I = dyn_cast<Instruction>(P.getPointer())) { |
| auto toRemoveIt = ReverseNonLocalDefsCache.find(I); |
| if (toRemoveIt != ReverseNonLocalDefsCache.end()) { |
| for (const auto *entry : toRemoveIt->second) |
| NonLocalDefsCache.erase(entry); |
| ReverseNonLocalDefsCache.erase(toRemoveIt); |
| } |
| } |
| } |
| |
| 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 (const NonLocalDepEntry &DE : PInfo) { |
| Instruction *Target = DE.getResult().getInst(); |
| if (!Target) |
| continue; // Ignore non-local dep results. |
| assert(Target->getParent() == DE.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); |
| } |
| |
| void MemoryDependenceResults::invalidateCachedPointerInfo(Value *Ptr) { |
| // If Ptr isn't really a pointer, just ignore it. |
| if (!Ptr->getType()->isPointerTy()) |
| return; |
| // Flush store info for the pointer. |
| removeCachedNonLocalPointerDependencies(ValueIsLoadPair(Ptr, false)); |
| // Flush load info for the pointer. |
| removeCachedNonLocalPointerDependencies(ValueIsLoadPair(Ptr, true)); |
| // Invalidate phis that use the pointer. |
| PV.invalidateValue(Ptr); |
| } |
| |
| void MemoryDependenceResults::invalidateCachedPredecessors() { |
| PredCache.clear(); |
| } |
| |
| void MemoryDependenceResults::removeInstruction(Instruction *RemInst) { |
| // Walk through the Non-local dependencies, removing this one as the value |
| // for any cached queries. |
| NonLocalDepMapType::iterator NLDI = NonLocalDepsMap.find(RemInst); |
| if (NLDI != NonLocalDepsMap.end()) { |
| NonLocalDepInfo &BlockMap = NLDI->second.first; |
| for (auto &Entry : BlockMap) |
| if (Instruction *Inst = Entry.getResult().getInst()) |
| RemoveFromReverseMap(ReverseNonLocalDeps, Inst, RemInst); |
| NonLocalDepsMap.erase(NLDI); |
| } |
| |
| // If we have a cached local dependence query for this instruction, remove it. |
| LocalDepMapType::iterator LocalDepEntry = LocalDeps.find(RemInst); |
| if (LocalDepEntry != LocalDeps.end()) { |
| // Remove us from DepInst's reverse set now that the local dep info is gone. |
| if (Instruction *Inst = LocalDepEntry->second.getInst()) |
| RemoveFromReverseMap(ReverseLocalDeps, Inst, RemInst); |
| |
| // Remove this local dependency info. |
| LocalDeps.erase(LocalDepEntry); |
| } |
| |
| // If we have any cached dependencies on this instruction, remove |
| // them. |
| |
| // If the instruction is a pointer, remove it from both the load info and the |
| // store info. |
| if (RemInst->getType()->isPointerTy()) { |
| removeCachedNonLocalPointerDependencies(ValueIsLoadPair(RemInst, false)); |
| removeCachedNonLocalPointerDependencies(ValueIsLoadPair(RemInst, true)); |
| } else { |
| // Otherwise, if the instructions is in the map directly, it must be a load. |
| // Remove it. |
| auto toRemoveIt = NonLocalDefsCache.find(RemInst); |
| if (toRemoveIt != NonLocalDefsCache.end()) { |
| assert(isa<LoadInst>(RemInst) && |
| "only load instructions should be added directly"); |
| const Instruction *DepV = toRemoveIt->second.getResult().getInst(); |
| ReverseNonLocalDefsCache.find(DepV)->second.erase(RemInst); |
| NonLocalDefsCache.erase(toRemoveIt); |
| } |
| } |
| |
| // Loop over all of the things that depend on the instruction we're removing. |
| SmallVector<std::pair<Instruction *, Instruction *>, 8> ReverseDepsToAdd; |
| |
| // If we find RemInst as a clobber or Def in any of the maps for other values, |
| // we need to replace its entry with a dirty version of the instruction after |
| // it. If RemInst is a terminator, we use a null dirty value. |
| // |
| // Using a dirty version of the instruction after RemInst saves having to scan |
| // the entire block to get to this point. |
| MemDepResult NewDirtyVal; |
| if (!RemInst->isTerminator()) |
| NewDirtyVal = MemDepResult::getDirty(&*++RemInst->getIterator()); |
| |
| ReverseDepMapType::iterator ReverseDepIt = ReverseLocalDeps.find(RemInst); |
| if (ReverseDepIt != ReverseLocalDeps.end()) { |
| // RemInst can't be the terminator if it has local stuff depending on it. |
| assert(!ReverseDepIt->second.empty() && !RemInst->isTerminator() && |
| "Nothing can locally depend on a terminator"); |
| |
| for (Instruction *InstDependingOnRemInst : ReverseDepIt->second) { |
| 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(), InstDependingOnRemInst)); |
| } |
| |
| ReverseLocalDeps.erase(ReverseDepIt); |
| |
| // Add new reverse deps after scanning the set, to avoid invalidating the |
| // 'ReverseDeps' reference. |
| while (!ReverseDepsToAdd.empty()) { |
| ReverseLocalDeps[ReverseDepsToAdd.back().first].insert( |
| ReverseDepsToAdd.back().second); |
| ReverseDepsToAdd.pop_back(); |
| } |
| } |
| |
| ReverseDepIt = ReverseNonLocalDeps.find(RemInst); |
| if (ReverseDepIt != ReverseNonLocalDeps.end()) { |
| for (Instruction *I : ReverseDepIt->second) { |
| assert(I != RemInst && "Already removed NonLocalDep info for RemInst"); |
| |
| PerInstNLInfo &INLD = NonLocalDepsMap[I]; |
| // The information is now dirty! |
| INLD.second = true; |
| |
| for (auto &Entry : INLD.first) { |
| if (Entry.getResult().getInst() != RemInst) |
| continue; |
| |
| // Convert to a dirty entry for the subsequent instruction. |
| Entry.setResult(NewDirtyVal); |
| |
| if (Instruction *NextI = NewDirtyVal.getInst()) |
| ReverseDepsToAdd.push_back(std::make_pair(NextI, I)); |
| } |
| } |
| |
| ReverseNonLocalDeps.erase(ReverseDepIt); |
| |
| // Add new reverse deps after scanning the set, to avoid invalidating 'Set' |
| while (!ReverseDepsToAdd.empty()) { |
| ReverseNonLocalDeps[ReverseDepsToAdd.back().first].insert( |
| ReverseDepsToAdd.back().second); |
| ReverseDepsToAdd.pop_back(); |
| } |
| } |
| |
| // If the instruction is in ReverseNonLocalPtrDeps then it appears as a |
| // value in the NonLocalPointerDeps info. |
| ReverseNonLocalPtrDepTy::iterator ReversePtrDepIt = |
| ReverseNonLocalPtrDeps.find(RemInst); |
| if (ReversePtrDepIt != ReverseNonLocalPtrDeps.end()) { |
| SmallVector<std::pair<Instruction *, ValueIsLoadPair>, 8> |
| ReversePtrDepsToAdd; |
| |
| for (ValueIsLoadPair P : ReversePtrDepIt->second) { |
| 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 (auto &Entry : NLPDI) { |
| if (Entry.getResult().getInst() != RemInst) |
| continue; |
| |
| // Convert to a dirty entry for the subsequent instruction. |
| Entry.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. |
| llvm::sort(NLPDI); |
| } |
| |
| ReverseNonLocalPtrDeps.erase(ReversePtrDepIt); |
| |
| while (!ReversePtrDepsToAdd.empty()) { |
| ReverseNonLocalPtrDeps[ReversePtrDepsToAdd.back().first].insert( |
| ReversePtrDepsToAdd.back().second); |
| ReversePtrDepsToAdd.pop_back(); |
| } |
| } |
| |
| // Invalidate phis that use the removed instruction. |
| PV.invalidateValue(RemInst); |
| |
| assert(!NonLocalDepsMap.count(RemInst) && "RemInst got reinserted?"); |
| LLVM_DEBUG(verifyRemoved(RemInst)); |
| } |
| |
| /// Verify that the specified instruction does not occur in our internal data |
| /// structures. |
| /// |
| /// This function verifies by asserting in debug builds. |
| void MemoryDependenceResults::verifyRemoved(Instruction *D) const { |
| #ifndef NDEBUG |
| for (const auto &DepKV : LocalDeps) { |
| assert(DepKV.first != D && "Inst occurs in data structures"); |
| assert(DepKV.second.getInst() != D && "Inst occurs in data structures"); |
| } |
| |
| for (const auto &DepKV : NonLocalPointerDeps) { |
| assert(DepKV.first.getPointer() != D && "Inst occurs in NLPD map key"); |
| for (const auto &Entry : DepKV.second.NonLocalDeps) |
| assert(Entry.getResult().getInst() != D && "Inst occurs as NLPD value"); |
| } |
| |
| for (const auto &DepKV : NonLocalDepsMap) { |
| assert(DepKV.first != D && "Inst occurs in data structures"); |
| const PerInstNLInfo &INLD = DepKV.second; |
| for (const auto &Entry : INLD.first) |
| assert(Entry.getResult().getInst() != D && |
| "Inst occurs in data structures"); |
| } |
| |
| for (const auto &DepKV : ReverseLocalDeps) { |
| assert(DepKV.first != D && "Inst occurs in data structures"); |
| for (Instruction *Inst : DepKV.second) |
| assert(Inst != D && "Inst occurs in data structures"); |
| } |
| |
| for (const auto &DepKV : ReverseNonLocalDeps) { |
| assert(DepKV.first != D && "Inst occurs in data structures"); |
| for (Instruction *Inst : DepKV.second) |
| assert(Inst != D && "Inst occurs in data structures"); |
| } |
| |
| for (const auto &DepKV : ReverseNonLocalPtrDeps) { |
| assert(DepKV.first != D && "Inst occurs in rev NLPD map"); |
| |
| for (ValueIsLoadPair P : DepKV.second) |
| assert(P != ValueIsLoadPair(D, false) && P != ValueIsLoadPair(D, true) && |
| "Inst occurs in ReverseNonLocalPtrDeps map"); |
| } |
| #endif |
| } |
| |
| AnalysisKey MemoryDependenceAnalysis::Key; |
| |
| MemoryDependenceAnalysis::MemoryDependenceAnalysis() |
| : DefaultBlockScanLimit(BlockScanLimit) {} |
| |
| MemoryDependenceResults |
| MemoryDependenceAnalysis::run(Function &F, FunctionAnalysisManager &AM) { |
| auto &AA = AM.getResult<AAManager>(F); |
| auto &AC = AM.getResult<AssumptionAnalysis>(F); |
| auto &TLI = AM.getResult<TargetLibraryAnalysis>(F); |
| auto &DT = AM.getResult<DominatorTreeAnalysis>(F); |
| auto &PV = AM.getResult<PhiValuesAnalysis>(F); |
| return MemoryDependenceResults(AA, AC, TLI, DT, PV, DefaultBlockScanLimit); |
| } |
| |
| char MemoryDependenceWrapperPass::ID = 0; |
| |
| INITIALIZE_PASS_BEGIN(MemoryDependenceWrapperPass, "memdep", |
| "Memory Dependence Analysis", false, true) |
| INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker) |
| INITIALIZE_PASS_DEPENDENCY(AAResultsWrapperPass) |
| INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass) |
| INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass) |
| INITIALIZE_PASS_DEPENDENCY(PhiValuesWrapperPass) |
| INITIALIZE_PASS_END(MemoryDependenceWrapperPass, "memdep", |
| "Memory Dependence Analysis", false, true) |
| |
| MemoryDependenceWrapperPass::MemoryDependenceWrapperPass() : FunctionPass(ID) { |
| initializeMemoryDependenceWrapperPassPass(*PassRegistry::getPassRegistry()); |
| } |
| |
| MemoryDependenceWrapperPass::~MemoryDependenceWrapperPass() = default; |
| |
| void MemoryDependenceWrapperPass::releaseMemory() { |
| MemDep.reset(); |
| } |
| |
| void MemoryDependenceWrapperPass::getAnalysisUsage(AnalysisUsage &AU) const { |
| AU.setPreservesAll(); |
| AU.addRequired<AssumptionCacheTracker>(); |
| AU.addRequired<DominatorTreeWrapperPass>(); |
| AU.addRequired<PhiValuesWrapperPass>(); |
| AU.addRequiredTransitive<AAResultsWrapperPass>(); |
| AU.addRequiredTransitive<TargetLibraryInfoWrapperPass>(); |
| } |
| |
| bool MemoryDependenceResults::invalidate(Function &F, const PreservedAnalyses &PA, |
| FunctionAnalysisManager::Invalidator &Inv) { |
| // Check whether our analysis is preserved. |
| auto PAC = PA.getChecker<MemoryDependenceAnalysis>(); |
| if (!PAC.preserved() && !PAC.preservedSet<AllAnalysesOn<Function>>()) |
| // If not, give up now. |
| return true; |
| |
| // Check whether the analyses we depend on became invalid for any reason. |
| if (Inv.invalidate<AAManager>(F, PA) || |
| Inv.invalidate<AssumptionAnalysis>(F, PA) || |
| Inv.invalidate<DominatorTreeAnalysis>(F, PA) || |
| Inv.invalidate<PhiValuesAnalysis>(F, PA)) |
| return true; |
| |
| // Otherwise this analysis result remains valid. |
| return false; |
| } |
| |
| unsigned MemoryDependenceResults::getDefaultBlockScanLimit() const { |
| return DefaultBlockScanLimit; |
| } |
| |
| bool MemoryDependenceWrapperPass::runOnFunction(Function &F) { |
| auto &AA = getAnalysis<AAResultsWrapperPass>().getAAResults(); |
| auto &AC = getAnalysis<AssumptionCacheTracker>().getAssumptionCache(F); |
| auto &TLI = getAnalysis<TargetLibraryInfoWrapperPass>().getTLI(F); |
| auto &DT = getAnalysis<DominatorTreeWrapperPass>().getDomTree(); |
| auto &PV = getAnalysis<PhiValuesWrapperPass>().getResult(); |
| MemDep.emplace(AA, AC, TLI, DT, PV, BlockScanLimit); |
| return false; |
| } |