#include "llvm/Pass.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/ADT/OwningPtr.h"
#include "llvm/ADT/PointerIntPair.h"
namespace llvm {
class FunctionPass;
class Instruction;
class CallSite;
+ class AliasAnalysis;
+ class TargetData;
+ class MemoryDependenceAnalysis;
+ class PredIteratorCache;
/// MemDepResult - A memory dependence query can return one of three different
- /// answers:
- /// Normal : The query is dependent on a specific instruction.
- /// NonLocal: The query does not depend on anything inside this block, but
- /// we haven't scanned beyond the block to find out what.
- /// None : The query does not depend on anything: we found the entry
- /// block or the allocation site of the memory.
+ /// answers, described below.
class MemDepResult {
enum DepType {
- Invalid = 0, Normal, NonLocal, None
+ /// Invalid - Clients of MemDep never see this.
+ Invalid = 0,
+
+ /// Clobber - This is a dependence on the specified instruction which
+ /// clobbers the desired value. The pointer member of the MemDepResult
+ /// 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.
+ Clobber,
+
+ /// Def - This is a dependence on the specified instruction which
+ /// defines/produces the desired memory location. The pointer member of
+ /// the MemDepResult pair holds the instruction that defines the memory.
+ /// Cases of interest:
+ /// 1. This could be a load or store for dependence queries on
+ /// load/store. The value loaded or stored is the produced value.
+ /// Note that the pointer operand may be different than that of the
+ /// queried pointer due to must aliases and phi translation. Note
+ /// that the def may not be the same type as the query, the pointers
+ /// may just be must aliases.
+ /// 2. For loads and stores, this could be an allocation instruction. In
+ /// 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.
+ Def,
+
+ /// 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
};
typedef PointerIntPair<Instruction*, 2, DepType> PairTy;
PairTy Value;
/// get methods: These are static ctor methods for creating various
/// MemDepResult kinds.
- static MemDepResult get(Instruction *Inst) {
- return MemDepResult(PairTy(Inst, Normal));
+ static MemDepResult getDef(Instruction *Inst) {
+ return MemDepResult(PairTy(Inst, Def));
+ }
+ static MemDepResult getClobber(Instruction *Inst) {
+ return MemDepResult(PairTy(Inst, Clobber));
}
static MemDepResult getNonLocal() {
return MemDepResult(PairTy(0, NonLocal));
}
- static MemDepResult getNone() {
- return MemDepResult(PairTy(0, None));
- }
- /// isNormal - Return true if this MemDepResult represents a query that is
- /// a normal instruction dependency.
- bool isNormal() const { return Value.getInt() == Normal; }
+ /// isClobber - Return true if this MemDepResult represents a query that is
+ /// a 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.
+ bool isDef() const { return Value.getInt() == Def; }
/// isNonLocal - Return true if this MemDepResult represents an 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; }
- /// isNone - Return true if this MemDepResult represents a query that
- /// doesn't depend on any instruction.
- bool isNone() const { return Value.getInt() == None; }
-
/// getInst() - If this is a normal dependency, return the instruction that
/// is depended on. Otherwise, return null.
- Instruction *getInst() const { return isNormal() ? Value.getPointer() : 0; }
+ Instruction *getInst() const { return Value.getPointer(); }
- bool operator==(const MemDepResult &M) { return M.Value == Value; }
- bool operator!=(const MemDepResult &M) { 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 M.Value > Value; }
+ private:
+ friend class MemoryDependenceAnalysis;
+ /// Dirty - Entries with this marker occur in a LocalDeps map or
+ /// NonLocalDeps map when the instruction they previously referenced was
+ /// removed from MemDep. In either case, the entry may include an
+ /// instruction pointer. If so, the pointer is an instruction in the
+ /// block where scanning can start from, saving some work.
+ ///
+ /// In a default-constructed MemDepResult object, the type will be Dirty
+ /// and the instruction pointer will be null.
+ ///
+
+ /// isDirty - Return true if this is a MemDepResult in its dirty/invalid.
+ /// state.
+ bool isDirty() const { return Value.getInt() == Invalid; }
+
+ static MemDepResult getDirty(Instruction *Inst) {
+ return MemDepResult(PairTy(Inst, Invalid));
+ }
};
/// MemoryDependenceAnalysis - This is an analysis that determines, for a
/// internal caching mechanism.
///
class MemoryDependenceAnalysis : public FunctionPass {
- /// DepType - This enum is used to indicate what flavor of dependence this
- /// is. If the type is Normal, there is an associated instruction pointer.
- enum DepType {
- /// Dirty - Entries with this marker occur in a LocalDeps map or
- /// NonLocalDeps map when the instruction they previously referenced was
- /// removed from MemDep. In either case, the entry may include an
- /// instruction pointer. If so, the pointer is an instruction in the
- /// block where scanning can start from, saving some work.
- ///
- /// In a default-constructed DepResultTy object, the type will be Dirty
- /// and the instruction pointer will be null.
- ///
- Dirty = 0,
-
- /// Normal - This is a normal instruction dependence. The pointer member
- /// of the DepResultTy pair holds the instruction.
- Normal,
-
- /// None - This dependence type indicates that the query does not depend
- /// on any instructions, either because it is not a memory instruction or
- /// because it scanned to the definition of the memory (alloca/malloc)
- /// being accessed.
- None,
-
- /// 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
- };
- typedef PointerIntPair<Instruction*, 2, DepType> DepResultTy;
-
// A map from instructions to their dependency.
- typedef DenseMap<Instruction*, DepResultTy> LocalDepMapType;
+ typedef DenseMap<Instruction*, MemDepResult> LocalDepMapType;
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;
+
+ /// 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<BasicBlock*, NonLocalDepInfo> > CachedNonLocalPointerInfo;
+ CachedNonLocalPointerInfo NonLocalPointerDeps;
+
+ // A map from instructions to their non-local pointer dependencies.
+ // The elements of the SmallPtrSet are ValueIsLoadPair's.
+ typedef DenseMap<Instruction*,
+ SmallPtrSet<void*, 4> > 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.
+ typedef std::pair<NonLocalDepInfo, bool> PerInstNLInfo;
+
// A map from instructions to their non-local dependencies.
- typedef DenseMap<Instruction*,
- // This is an owning pointer.
- DenseMap<BasicBlock*, DepResultTy>*> NonLocalDepMapType;
+ typedef DenseMap<Instruction*, PerInstNLInfo> NonLocalDepMapType;
+
NonLocalDepMapType NonLocalDeps;
// A reverse mapping from dependencies to the dependees. This is
// A reverse mapping form dependencies to the non-local dependees.
ReverseDepMapType ReverseNonLocalDeps;
+ /// Current AA implementation, just a cache.
+ AliasAnalysis *AA;
+ TargetData *TD;
+ OwningPtr<PredIteratorCache> PredCache;
public:
- MemoryDependenceAnalysis() : FunctionPass(&ID) {}
+ MemoryDependenceAnalysis();
+ ~MemoryDependenceAnalysis();
static char ID;
- /// Pass Implementation stuff. This doesn't do any analysis.
- ///
- bool runOnFunction(Function &) {return false; }
+ /// Pass Implementation stuff. This doesn't do any analysis eagerly.
+ bool runOnFunction(Function &);
/// Clean up memory in between runs
- void releaseMemory() {
- LocalDeps.clear();
- for (NonLocalDepMapType::iterator I = NonLocalDeps.begin(),
- E = NonLocalDeps.end(); I != E; ++I)
- delete I->second;
- NonLocalDeps.clear();
- ReverseLocalDeps.clear();
- ReverseNonLocalDeps.clear();
- }
-
+ void releaseMemory();
+
/// getAnalysisUsage - Does not modify anything. It uses Value Numbering
/// and Alias Analysis.
///
virtual void getAnalysisUsage(AnalysisUsage &AU) const;
/// getDependency - Return the instruction on which a memory operation
- /// depends. See the class comment for more details.
+ /// depends. See the class comment for more details. It is illegal to call
+ /// this on non-memory instructions.
MemDepResult getDependency(Instruction *QueryInst);
- /// getDependencyFrom - Return the instruction on which the memory operation
- /// 'QueryInst' depends. This starts scanning from the instruction before
- /// the position indicated by ScanIt.
- ///
- /// Note that this method does no caching at all. You should use
- /// getDependency where possible.
- MemDepResult getDependencyFrom(Instruction *QueryInst,
- BasicBlock::iterator ScanIt, BasicBlock *BB){
- return ConvToResult(getDependencyFromInternal(QueryInst, ScanIt, BB));
- }
-
-
- /// 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.
///
- /// This method assumes the instruction returns a "nonlocal" dependency
+ /// This method assumes the instruction returns a "NonLocal" dependency
/// within its own block.
- void getNonLocalDependency(Instruction *QueryInst,
- SmallVectorImpl<std::pair<BasicBlock*,
- MemDepResult> > &Result);
+ ///
+ /// This returns a reference to an internal data structure that may be
+ /// 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 &getNonLocalCallDependency(CallSite QueryCS);
+
+
+ /// getNonLocalPointerDependency - Perform a full dependency query for an
+ /// access to the specified (non-volatile) memory location, returning the
+ /// 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);
/// removeInstruction - Remove an instruction from the dependence analysis,
/// updating the dependence of instructions that previously depended on it.
void removeInstruction(Instruction *InstToRemove);
private:
- MemDepResult ConvToResult(DepResultTy R) {
- if (R.getInt() == Normal)
- return MemDepResult::get(R.getPointer());
- if (R.getInt() == NonLocal)
- return MemDepResult::getNonLocal();
- assert(R.getInt() == None && "Unknown MemDepResult!");
- return MemDepResult::getNone();
- }
+ MemDepResult getPointerDependencyFrom(Value *Pointer, uint64_t MemSize,
+ bool isLoad,
+ BasicBlock::iterator ScanIt,
+ BasicBlock *BB);
+ MemDepResult getCallSiteDependencyFrom(CallSite C, bool isReadOnlyCall,
+ BasicBlock::iterator ScanIt,
+ BasicBlock *BB);
+ void getNonLocalPointerDepFromBB(Value *Pointer, uint64_t Size,
+ bool isLoad, BasicBlock *BB,
+ SmallVectorImpl<NonLocalDepEntry> &Result,
+ SmallPtrSet<BasicBlock*, 64> &Visited);
+ MemDepResult GetNonLocalInfoForBlock(Value *Pointer, uint64_t PointeeSize,
+ 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.
void verifyRemoved(Instruction *Inst) const;
- /// getDependencyFromInternal - Return the instruction on which the memory
- /// operation 'QueryInst' depends. This starts scanning from the
- /// instruction before the position indicated by ScanIt.
- DepResultTy getDependencyFromInternal(Instruction *QueryInst,
- BasicBlock::iterator ScanIt, BasicBlock *BB);
- DepResultTy getCallSiteDependency(CallSite C, BasicBlock::iterator ScanIt,
- BasicBlock *BB);
};
} // End llvm namespace
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