#ifndef LLVM_TRANSFORMS_UTILS_SSAUPDATER_H
#define LLVM_TRANSFORMS_UTILS_SSAUPDATER_H
+#include "llvm/ADT/StringRef.h"
+#include "llvm/Support/Compiler.h"
+
namespace llvm {
- class Value;
class BasicBlock;
- class Use;
+ class Instruction;
+ class LoadInst;
+ template<typename T> class SmallVectorImpl;
+ template<typename T> class SSAUpdaterTraits;
class PHINode;
- template<typename T>
- class SmallVectorImpl;
+ class Type;
+ class Use;
+ class Value;
-/// SSAUpdater - This class updates SSA form for a set of values defined in
-/// multiple blocks. This is used when code duplication or another unstructured
+/// \brief Helper class for SSA formation on a set of values defined in
+/// multiple blocks.
+///
+/// This is used when code duplication or another unstructured
/// transformation wants to rewrite a set of uses of one value with uses of a
/// set of values.
class SSAUpdater {
- /// AvailableVals - This keeps track of which value to use on a per-block
- /// basis. When we insert PHI nodes, we keep track of them here. We use
- /// WeakVH's for the value of the map because we RAUW PHI nodes when we
- /// eliminate them, and want the WeakVH to track this.
- //typedef DenseMap<BasicBlock*, TrackingVH<Value> > AvailableValsTy;
+ friend class SSAUpdaterTraits<SSAUpdater>;
+
+private:
+ /// This keeps track of which value to use on a per-block basis. When we
+ /// insert PHI nodes, we keep track of them here.
+ //typedef DenseMap<BasicBlock*, Value*> AvailableValsTy;
void *AV;
- /// PrototypeValue is an arbitrary representative value, which we derive names
- /// and a type for PHI nodes.
- Value *PrototypeValue;
+ /// ProtoType holds the type of the values being rewritten.
+ Type *ProtoType;
- /// IncomingPredInfo - We use this as scratch space when doing our recursive
- /// walk. This should only be used in GetValueInBlockInternal, normally it
- /// should be empty.
- //std::vector<std::pair<BasicBlock*, TrackingVH<Value> > > IncomingPredInfo;
- void *IPI;
+ /// PHI nodes are given a name based on ProtoName.
+ std::string ProtoName;
- /// InsertedPHIs - If this is non-null, the SSAUpdater adds all PHI nodes that
- /// it creates to the vector.
+ /// If this is non-null, the SSAUpdater adds all PHI nodes that it creates to
+ /// the vector.
SmallVectorImpl<PHINode*> *InsertedPHIs;
+
public:
- /// SSAUpdater constructor. If InsertedPHIs is specified, it will be filled
+ /// If InsertedPHIs is specified, it will be filled
/// in with all PHI Nodes created by rewriting.
- SSAUpdater(SmallVectorImpl<PHINode*> *InsertedPHIs = 0);
+
explicit SSAUpdater(SmallVectorImpl<PHINode*> *InsertedPHIs = 0);
~SSAUpdater();
- /// Initialize - Reset this object to get ready for a new set of SSA
- /// updates. ProtoValue is the value used to name PHI nodes.
- void Initialize(Value *ProtoValue);
+ /// \brief Reset this object to get ready for a new set of SSA updates with
+ /// type 'Ty'.
+ ///
+ /// PHI nodes get a name based on 'Name'.
+ void Initialize(Type *Ty, StringRef Name);
- /// AddAvailableValue - Indicate that a rewritten value is available at the
- /// end of the specified block with the specified value.
+ /// \brief Indicate that a rewritten value is available in the specified block
+ /// with the specified value.
void AddAvailableValue(BasicBlock *BB, Value *V);
- /// HasValueForBlock - Return true if the SSAUpdater already has a value for
- /// the specified block.
+ /// \brief Return true if the SSAUpdater already has a value for the specified
+ /// block.
bool HasValueForBlock(BasicBlock *BB) const;
- /// GetValueAtEndOfBlock - Construct SSA form, materializing a value that is
- /// live at the end of the specified block.
+ /// \brief Construct SSA form, materializing a value that is live at the end
+ /// of the specified block.
Value *GetValueAtEndOfBlock(BasicBlock *BB);
- /// GetValueInMiddleOfBlock - Construct SSA form, materializing a value that
- /// is live in the middle of the specified block.
+ /// \brief Construct SSA form, materializing a value that is live in the
+ /// middle of the specified block.
///
- /// GetValueInMiddleOfBlock is the same as GetValueAtEndOfBlock except in one
- /// important case: if there is a definition of the rewritten value after the
- /// 'use' in BB. Consider code like this:
+ /// \c GetValueInMiddleOfBlock is the same as \c GetValueAtEndOfBlock except
+ /// in one important case: if there is a definition of the rewritten value
+ /// after the 'use' in BB. Consider code like this:
///
+ /// \code
/// X1 = ...
/// SomeBB:
/// use(X)
/// X2 = ...
/// br Cond, SomeBB, OutBB
+ /// \endcode
///
/// In this case, there are two values (X1 and X2) added to the AvailableVals
/// set by the client of the rewriter, and those values are both live out of
/// their respective blocks. However, the use of X happens in the *middle* of
/// a block. Because of this, we need to insert a new PHI node in SomeBB to
/// merge the appropriate values, and this value isn't live out of the block.
- ///
Value *GetValueInMiddleOfBlock(BasicBlock *BB);
- /// RewriteUse - Rewrite a use of the symbolic value. This handles PHI nodes,
- /// which use their value in the corresponding predecessor. Note that this
- /// will not work if the use is supposed to be rewritten to a value defined in
- /// the same block as the use, but above it. Any 'AddAvailableValue's added
- /// for the use's block will be considered to be below it.
+ /// \brief Rewrite a use of the symbolic value.
+ ///
+ /// This handles PHI nodes, which use their value in the corresponding
+ /// predecessor. Note that this will not work if the use is supposed to be
+ /// rewritten to a value defined in the same block as the use, but above it.
+ /// Any 'AddAvailableValue's added for the use's block will be considered to
+ /// be below it.
void RewriteUse(Use &U);
+ /// \brief Rewrite a use like \c RewriteUse but handling in-block definitions.
+ ///
+ /// This version of the method can rewrite uses in the same block as
+ /// a definition, because it assumes that all uses of a value are below any
+ /// inserted values.
+ void RewriteUseAfterInsertions(Use &U);
+
private:
Value *GetValueAtEndOfBlockInternal(BasicBlock *BB);
- void operator=(const SSAUpdater&); // DO NOT IMPLEMENT
- SSAUpdater(const SSAUpdater&); // DO NOT IMPLEMENT
+
+ void operator=(const SSAUpdater&) LLVM_DELETED_FUNCTION;
+ SSAUpdater(const SSAUpdater&) LLVM_DELETED_FUNCTION;
+};
+
+/// \brief Helper class for promoting a collection of loads and stores into SSA
+/// Form using the SSAUpdater.
+///
+/// This handles complexities that SSAUpdater doesn't, such as multiple loads
+/// and stores in one block.
+///
+/// Clients of this class are expected to subclass this and implement the
+/// virtual methods.
+class LoadAndStorePromoter {
+protected:
+ SSAUpdater &SSA;
+public:
+ LoadAndStorePromoter(const SmallVectorImpl<Instruction*> &Insts,
+ SSAUpdater &S, StringRef Name = StringRef());
+ virtual ~LoadAndStorePromoter() {}
+
+ /// \brief This does the promotion.
+ ///
+ /// Insts is a list of loads and stores to promote, and Name is the basename
+ /// for the PHIs to insert. After this is complete, the loads and stores are
+ /// removed from the code.
+ void run(const SmallVectorImpl<Instruction*> &Insts) const;
+
+
+ /// \brief Return true if the specified instruction is in the Inst list.
+ ///
+ /// The Insts list is the one passed into the constructor. Clients should
+ /// implement this with a more efficient version if possible.
+ virtual bool isInstInList(Instruction *I,
+ const SmallVectorImpl<Instruction*> &Insts) const;
+
+ /// \brief This hook is invoked after all the stores are found and inserted as
+ /// available values.
+ virtual void doExtraRewritesBeforeFinalDeletion() const {
+ }
+
+ /// \brief Clients can choose to implement this to get notified right before
+ /// a load is RAUW'd another value.
+ virtual void replaceLoadWithValue(LoadInst *LI, Value *V) const {
+ }
+
+ /// \brief Called before each instruction is deleted.
+ virtual void instructionDeleted(Instruction *I) const {
+ }
+
+ /// \brief Called to update debug info associated with the instruction.
+ virtual void updateDebugInfo(Instruction *I) const {
+ }
};
} // End llvm namespace
projects / oota-llvm.git / blobdiff