X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=include%2Fllvm%2FAnalysis%2FMemoryDependenceAnalysis.h;h=121eede1c0e419a1a61710b9990d523e1038fa5c;hb=b09c146b116359616f6cbd4c8b3328607e00ff42;hp=e2dd6629b748effa9fdc88e165bdd1e5426cbe68;hpb=9a193fd8ae630478123938e12b56f84c5b2227b9;p=oota-llvm.git diff --git a/include/llvm/Analysis/MemoryDependenceAnalysis.h b/include/llvm/Analysis/MemoryDependenceAnalysis.h index e2dd6629b74..121eede1c0e 100644 --- a/include/llvm/Analysis/MemoryDependenceAnalysis.h +++ b/include/llvm/Analysis/MemoryDependenceAnalysis.h @@ -14,11 +14,14 @@ #ifndef LLVM_ANALYSIS_MEMORY_DEPENDENCE_H #define LLVM_ANALYSIS_MEMORY_DEPENDENCE_H -#include "llvm/BasicBlock.h" -#include "llvm/Pass.h" #include "llvm/ADT/DenseMap.h" -#include "llvm/ADT/SmallPtrSet.h" +#include "llvm/ADT/OwningPtr.h" #include "llvm/ADT/PointerIntPair.h" +#include "llvm/ADT/SmallPtrSet.h" +#include "llvm/Analysis/AliasAnalysis.h" +#include "llvm/BasicBlock.h" +#include "llvm/Pass.h" +#include "llvm/Support/ValueHandle.h" namespace llvm { class Function; @@ -26,8 +29,11 @@ namespace llvm { class Instruction; class CallSite; class AliasAnalysis; - class TargetData; + class DataLayout; class MemoryDependenceAnalysis; + class PredIteratorCache; + class DominatorTree; + class PHITransAddr; /// MemDepResult - A memory dependence query can return one of three different /// answers, described below. @@ -41,6 +47,11 @@ namespace llvm { /// pair holds the instruction that clobbers the memory. For example, /// this occurs when we see a may-aliased store to the memory location we /// care about. + /// + /// There are several cases that may be interesting here: + /// 1. Loads are clobbered by may-alias stores. + /// 2. Loads are considered clobbered by partially-aliased loads. The + /// client may choose to analyze deeper into these cases. Clobber, /// Def - This is a dependence on the specified instruction which @@ -57,16 +68,32 @@ namespace llvm { /// this case, the load is loading an undef value or a store is the /// first store to (that part of) the allocation. /// 3. Dependence queries on calls return Def only when they are - /// readonly calls with identical callees and no intervening - /// clobbers. No validation is done that the operands to the calls - /// are the same. + /// readonly calls or memory use intrinsics with identical callees + /// and no intervening clobbers. No validation is done that the + /// operands to the calls are the same. Def, + /// Other - This marker indicates that the query has no known dependency + /// in the specified block. More detailed state info is encoded in the + /// upper part of the pair (i.e. the Instruction*) + Other + }; + /// If DepType is "Other", the upper part of the pair + /// (i.e. the Instruction* part) is instead used to encode more detailed + /// type information as follows + enum OtherType { /// NonLocal - This marker indicates that the query has no dependency in /// the specified block. To find out more, the client should query other /// predecessor blocks. - NonLocal + NonLocal = 0x4, + /// NonFuncLocal - This marker indicates that the query has no + /// dependency in the specified function. + NonFuncLocal = 0x8, + /// Unknown - This marker indicates that the query dependency + /// is unknown. + Unknown = 0xc }; + typedef PointerIntPair PairTy; PairTy Value; explicit MemDepResult(PairTy V) : Value(V) {} @@ -76,36 +103,67 @@ namespace llvm { /// get methods: These are static ctor methods for creating various /// MemDepResult kinds. static MemDepResult getDef(Instruction *Inst) { + assert(Inst && "Def requires inst"); return MemDepResult(PairTy(Inst, Def)); } static MemDepResult getClobber(Instruction *Inst) { + assert(Inst && "Clobber requires inst"); return MemDepResult(PairTy(Inst, Clobber)); } static MemDepResult getNonLocal() { - return MemDepResult(PairTy(0, NonLocal)); + return MemDepResult( + PairTy(reinterpret_cast(NonLocal), Other)); + } + static MemDepResult getNonFuncLocal() { + return MemDepResult( + PairTy(reinterpret_cast(NonFuncLocal), Other)); + } + static MemDepResult getUnknown() { + return MemDepResult( + PairTy(reinterpret_cast(Unknown), Other)); } /// isClobber - Return true if this MemDepResult represents a query that is - /// a instruction clobber dependency. + /// an instruction clobber dependency. bool isClobber() const { return Value.getInt() == Clobber; } /// isDef - Return true if this MemDepResult represents a query that is - /// a instruction definition dependency. + /// an instruction definition dependency. bool isDef() const { return Value.getInt() == Def; } - /// isNonLocal - Return true if this MemDepResult represents an query that + /// isNonLocal - Return true if this MemDepResult represents a query that /// is transparent to the start of the block, but where a non-local hasn't /// been done. - bool isNonLocal() const { return Value.getInt() == NonLocal; } + bool isNonLocal() const { + return Value.getInt() == Other + && Value.getPointer() == reinterpret_cast(NonLocal); + } + + /// isNonFuncLocal - Return true if this MemDepResult represents a query + /// that is transparent to the start of the function. + bool isNonFuncLocal() const { + return Value.getInt() == Other + && Value.getPointer() == reinterpret_cast(NonFuncLocal); + } + /// isUnknown - Return true if this MemDepResult represents a query which + /// cannot and/or will not be computed. + bool isUnknown() const { + return Value.getInt() == Other + && Value.getPointer() == reinterpret_cast(Unknown); + } + /// getInst() - If this is a normal dependency, return the instruction that /// is depended on. Otherwise, return null. - Instruction *getInst() const { return Value.getPointer(); } + Instruction *getInst() const { + if (Value.getInt() == Other) return NULL; + return Value.getPointer(); + } - bool operator==(const MemDepResult &M) const { return M.Value == Value; } - bool operator!=(const MemDepResult &M) const { return M.Value != Value; } - bool operator<(const MemDepResult &M) const { return M.Value < Value; } - bool operator>(const MemDepResult &M) const { return M.Value > Value; } + bool operator==(const MemDepResult &M) const { return Value == M.Value; } + bool operator!=(const MemDepResult &M) const { return Value != M.Value; } + bool operator<(const MemDepResult &M) const { return Value < M.Value; } + bool operator>(const MemDepResult &M) const { return Value > M.Value; } private: friend class MemoryDependenceAnalysis; /// Dirty - Entries with this marker occur in a LocalDeps map or @@ -127,6 +185,60 @@ namespace llvm { } }; + /// NonLocalDepEntry - This is an entry in the NonLocalDepInfo cache. For + /// each BasicBlock (the BB entry) it keeps a MemDepResult. + class NonLocalDepEntry { + BasicBlock *BB; + MemDepResult Result; + public: + NonLocalDepEntry(BasicBlock *bb, MemDepResult result) + : BB(bb), Result(result) {} + + // This is used for searches. + NonLocalDepEntry(BasicBlock *bb) : BB(bb) {} + + // BB is the sort key, it can't be changed. + BasicBlock *getBB() const { return BB; } + + void setResult(const MemDepResult &R) { Result = R; } + + const MemDepResult &getResult() const { return Result; } + + bool operator<(const NonLocalDepEntry &RHS) const { + return BB < RHS.BB; + } + }; + + /// NonLocalDepResult - This is a result from a NonLocal dependence query. + /// For each BasicBlock (the BB entry) it keeps a MemDepResult and the + /// (potentially phi translated) address that was live in the block. + class NonLocalDepResult { + NonLocalDepEntry Entry; + Value *Address; + public: + NonLocalDepResult(BasicBlock *bb, MemDepResult result, Value *address) + : Entry(bb, result), Address(address) {} + + // BB is the sort key, it can't be changed. + BasicBlock *getBB() const { return Entry.getBB(); } + + void setResult(const MemDepResult &R, Value *Addr) { + Entry.setResult(R); + Address = Addr; + } + + const MemDepResult &getResult() const { return Entry.getResult(); } + + /// getAddress - Return the address of this pointer in this block. This can + /// be different than the address queried for the non-local result because + /// of phi translation. This returns null if the address was not available + /// in a block (i.e. because phi translation failed) or if this is a cached + /// result and that address was deleted. + /// + /// The address is always null for a non-local 'call' dependence. + Value *getAddress() const { return Address; } + }; + /// MemoryDependenceAnalysis - This is 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, @@ -148,10 +260,48 @@ namespace llvm { LocalDepMapType LocalDeps; public: - typedef std::pair NonLocalDepEntry; typedef std::vector NonLocalDepInfo; private: - + /// ValueIsLoadPair - This is a pair where the bool is true if + /// the dependence is a read only dependence, false if read/write. + typedef PointerIntPair ValueIsLoadPair; + + /// BBSkipFirstBlockPair - This pair is used when caching information for a + /// block. If the pointer is null, the cache value is not a full query that + /// starts at the specified block. If non-null, the bool indicates whether + /// or not the contents of the block was skipped. + typedef PointerIntPair BBSkipFirstBlockPair; + + /// NonLocalPointerInfo - This record is the information kept for each + /// (value, is load) pair. + struct NonLocalPointerInfo { + /// Pair - The pair of the block and the skip-first-block flag. + BBSkipFirstBlockPair Pair; + /// NonLocalDeps - The results of the query for each relevant block. + NonLocalDepInfo NonLocalDeps; + /// Size - The maximum size of the dereferences of the + /// pointer. May be UnknownSize if the sizes are unknown. + uint64_t Size; + /// TBAATag - The TBAA tag associated with dereferences of the + /// pointer. May be null if there are no tags or conflicting tags. + const MDNode *TBAATag; + + NonLocalPointerInfo() : Size(AliasAnalysis::UnknownSize), TBAATag(0) {} + }; + + /// CachedNonLocalPointerInfo - This map stores the cached results of doing + /// a pointer lookup at the bottom of a block. The key of this map is the + /// pointer+isload bit, the value is a list of result> mappings. + typedef DenseMap CachedNonLocalPointerInfo; + CachedNonLocalPointerInfo NonLocalPointerDeps; + + // A map from instructions to their non-local pointer dependencies. + typedef DenseMap > ReverseNonLocalPtrDepTy; + ReverseNonLocalPtrDepTy ReverseNonLocalPtrDeps; + + /// PerInstNLInfo - This is the instruction we keep for each cached access /// that we have for an instruction. The pointer is an owning pointer and /// the bool indicates whether we have any dirty bits in the set. @@ -168,28 +318,25 @@ namespace llvm { SmallPtrSet > ReverseDepMapType; ReverseDepMapType ReverseLocalDeps; - // A reverse mapping form dependencies to the non-local dependees. + // A reverse mapping from dependencies to the non-local dependees. ReverseDepMapType ReverseNonLocalDeps; /// Current AA implementation, just a cache. AliasAnalysis *AA; - TargetData *TD; + DataLayout *TD; + DominatorTree *DT; + OwningPtr PredCache; public: - MemoryDependenceAnalysis() : FunctionPass(&ID) {} + MemoryDependenceAnalysis(); + ~MemoryDependenceAnalysis(); static char ID; /// Pass Implementation stuff. This doesn't do any analysis eagerly. bool runOnFunction(Function &); /// Clean up memory in between runs - void releaseMemory() { - LocalDeps.clear(); - NonLocalDeps.clear(); - NonLocalDeps.clear(); - ReverseLocalDeps.clear(); - ReverseNonLocalDeps.clear(); - } - + void releaseMemory(); + /// getAnalysisUsage - Does not modify anything. It uses Value Numbering /// and Alias Analysis. /// @@ -200,8 +347,8 @@ namespace llvm { /// this on non-memory instructions. MemDepResult getDependency(Instruction *QueryInst); - /// getNonLocalDependency - Perform a full dependency query for the - /// specified instruction, returning the set of blocks that the value is + /// getNonLocalCallDependency - Perform a full dependency query for the + /// specified call, returning the set of blocks that the value is /// potentially live across. The returned set of results will include a /// "NonLocal" result for all blocks where the value is live across. /// @@ -212,7 +359,7 @@ namespace llvm { /// invalidated on the next non-local query or when an instruction is /// removed. Clients must copy this data if they want it around longer than /// that. - const NonLocalDepInfo &getNonLocalDependency(Instruction *QueryInst); + const NonLocalDepInfo &getNonLocalCallDependency(CallSite QueryCS); /// getNonLocalPointerDependency - Perform a full dependency query for an @@ -220,32 +367,69 @@ namespace llvm { /// set of instructions that either define or clobber the value. /// /// This method assumes the pointer has a "NonLocal" dependency within BB. - void getNonLocalPointerDependency(Value *Pointer, bool isLoad, - BasicBlock *BB, - SmallVectorImpl &Result); - + void getNonLocalPointerDependency(const AliasAnalysis::Location &Loc, + bool isLoad, BasicBlock *BB, + SmallVectorImpl &Result); + /// removeInstruction - Remove an instruction from the dependence analysis, /// updating the dependence of instructions that previously depended on it. void removeInstruction(Instruction *InstToRemove); - private: + /// invalidateCachedPointerInfo - This method is used to invalidate cached + /// information about the specified pointer, because it may be too + /// conservative in memdep. This is an optional call that can be used when + /// the client detects an equivalence between the pointer and some other + /// value and replaces the other value with ptr. This can make Ptr available + /// in more places that cached info does not necessarily keep. + void invalidateCachedPointerInfo(Value *Ptr); + + /// invalidateCachedPredecessors - Clear the PredIteratorCache info. + /// This needs to be done when the CFG changes, e.g., due to splitting + /// critical edges. + void invalidateCachedPredecessors(); - /// getDependencyFrom - Return the instruction on which the memory location - /// '*Pointer' depends. This starts scanning from the instruction before - /// the position indicated by ScanIt. - MemDepResult getPointerDependencyFrom(Value *Pointer, uint64_t MemSize, + /// 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. + /// + /// Note that this is an uncached query, and thus may be inefficient. + /// + MemDepResult getPointerDependencyFrom(const AliasAnalysis::Location &Loc, bool isLoad, BasicBlock::iterator ScanIt, BasicBlock *BB); - MemDepResult getCallSiteDependencyFrom(CallSite C, + + + /// getLoadLoadClobberFullWidthSize - This is a little bit of analysis that + /// looks at a memory location for a load (specified by MemLocBase, Offs, + /// and Size) and compares it against a load. If the specified load could + /// be safely widened to a larger integer load that is 1) still efficient, + /// 2) safe for the target, and 3) would provide the specified memory + /// location value, then this function returns the size in bytes of the + /// load width to use. If not, this returns zero. + static unsigned getLoadLoadClobberFullWidthSize(const Value *MemLocBase, + int64_t MemLocOffs, + unsigned MemLocSize, + const LoadInst *LI, + const DataLayout &TD); + + private: + MemDepResult getCallSiteDependencyFrom(CallSite C, bool isReadOnlyCall, BasicBlock::iterator ScanIt, BasicBlock *BB); - - void getNonLocalPointerDepInternal(Value *Pointer, uint64_t Size, - bool isLoad, BasicBlock *BB, - SmallVectorImpl &Result, - SmallPtrSet &Visited); - + bool getNonLocalPointerDepFromBB(const PHITransAddr &Pointer, + const AliasAnalysis::Location &Loc, + bool isLoad, BasicBlock *BB, + SmallVectorImpl &Result, + DenseMap &Visited, + bool SkipFirstBlock = false); + MemDepResult GetNonLocalInfoForBlock(const AliasAnalysis::Location &Loc, + bool isLoad, BasicBlock *BB, + NonLocalDepInfo *Cache, + unsigned NumSortedEntries); + + void RemoveCachedNonLocalPointerDependencies(ValueIsLoadPair P); /// verifyRemoved - Verify that the specified instruction does not occur /// in our internal data structures.