#include "llvm/BasicBlock.h"
#include "llvm/Pass.h"
+#include "llvm/Support/ValueHandle.h"
+#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/OwningPtr.h"
class MemoryDependenceAnalysis;
class PredIteratorCache;
class DominatorTree;
+ class PHITransAddr;
/// MemDepResult - A memory dependence query can return one of three different
/// answers, described below.
/// 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
/// 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<Instruction*, 2, DepType> PairTy;
PairTy Value;
explicit MemDepResult(PairTy V) : Value(V) {}
/// 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<Instruction*>(NonLocal), Other));
+ }
+ static MemDepResult getNonFuncLocal() {
+ return MemDepResult(
+ PairTy(reinterpret_cast<Instruction*>(NonFuncLocal), Other));
+ }
+ static MemDepResult getUnknown() {
+ return MemDepResult(
+ PairTy(reinterpret_cast<Instruction*>(Unknown), Other));
}
/// isClobber - Return true if this MemDepResult represents a query that is
/// 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<Instruction*>(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<Instruction*>(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<Instruction*>(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 Value == M.Value; }
bool operator!=(const MemDepResult &M) const { return Value != M.Value; }
}
};
+ /// 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,
LocalDepMapType LocalDeps;
public:
- typedef std::pair<BasicBlock*, MemDepResult> NonLocalDepEntry;
typedef std::vector<NonLocalDepEntry> NonLocalDepInfo;
private:
/// ValueIsLoadPair - This is a pair<Value*, bool> where the bool is true if
/// the dependence is a read only dependence, false if read/write.
- typedef PointerIntPair<Value*, 1, bool> ValueIsLoadPair;
+ typedef PointerIntPair<const Value*, 1, bool> 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
/// or not the contents of the block was skipped.
typedef PointerIntPair<BasicBlock*, 1, bool> 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 <bb->result> mappings.
- typedef DenseMap<ValueIsLoadPair, std::pair<BBSkipFirstBlockPair,
- NonLocalDepInfo> > CachedNonLocalPointerInfo;
+ typedef DenseMap<ValueIsLoadPair,
+ NonLocalPointerInfo> CachedNonLocalPointerInfo;
CachedNonLocalPointerInfo NonLocalPointerDeps;
// A map from instructions to their non-local pointer dependencies.
SmallPtrSet<Instruction*, 4> > 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.
/// 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<NonLocalDepEntry> &Result);
-
- /// GetPHITranslatedValue - Find an available version of the specified value
- /// PHI translated across the specified edge. If MemDep isn't able to
- /// satisfy this request, it returns null.
- Value *GetPHITranslatedValue(Value *V,
- BasicBlock *CurBB, BasicBlock *PredBB,
- const TargetData *TD) const;
+ void getNonLocalPointerDependency(const AliasAnalysis::Location &Loc,
+ bool isLoad, BasicBlock *BB,
+ SmallVectorImpl<NonLocalDepResult> &Result);
- /// GetAvailablePHITranslatedValue - Return the value computed by
- /// PHITranslatePointer if it dominates PredBB, otherwise return null.
- Value *GetAvailablePHITranslatedValue(Value *V,
- BasicBlock *CurBB, BasicBlock *PredBB,
- const TargetData *TD,
- const DominatorTree &DT) const;
-
- /// InsertPHITranslatedPointer - Insert a computation of the PHI translated
- /// version of 'V' for the edge PredBB->CurBB into the end of the PredBB
- /// block. All newly created instructions are added to the NewInsts list.
- Value *InsertPHITranslatedPointer(Value *V,
- BasicBlock *CurBB, BasicBlock *PredBB,
- const TargetData *TD,
- const DominatorTree &DT,
- SmallVectorImpl<Instruction*> &NewInsts) const;
-
/// removeInstruction - Remove an instruction from the dependence analysis,
/// updating the dependence of instructions that previously depended on it.
void removeInstruction(Instruction *InstToRemove);
/// 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();
- private:
- 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);
+
+
+ /// 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 TargetData &TD);
+
+ private:
MemDepResult getCallSiteDependencyFrom(CallSite C, bool isReadOnlyCall,
BasicBlock::iterator ScanIt,
BasicBlock *BB);
- bool getNonLocalPointerDepFromBB(Value *Pointer, uint64_t Size,
+ bool getNonLocalPointerDepFromBB(const PHITransAddr &Pointer,
+ const AliasAnalysis::Location &Loc,
bool isLoad, BasicBlock *BB,
- SmallVectorImpl<NonLocalDepEntry> &Result,
+ SmallVectorImpl<NonLocalDepResult> &Result,
DenseMap<BasicBlock*, Value*> &Visited,
bool SkipFirstBlock = false);
- MemDepResult GetNonLocalInfoForBlock(Value *Pointer, uint64_t PointeeSize,
+ MemDepResult GetNonLocalInfoForBlock(const AliasAnalysis::Location &Loc,
bool isLoad, BasicBlock *BB,
NonLocalDepInfo *Cache,
unsigned NumSortedEntries);
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