#ifndef LLVM_TRANSFORMS_UTILS_SSAUPDATER_H
#define LLVM_TRANSFORMS_UTILS_SSAUPDATER_H
+#include "llvm/ADT/StringRef.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
/// transformation wants to rewrite a set of uses of one value with uses of a
/// set of values.
class SSAUpdater {
-public:
- class BBInfo;
+ friend class SSAUpdaterTraits<SSAUpdater>;
private:
/// AvailableVals - This keeps track of which value to use on a per-block
//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;
- /// BBMap - The GetValueAtEndOfBlock method maintains this mapping from
- /// basic blocks to BBInfo structures.
- /// typedef DenseMap<BasicBlock*, BBInfo*> BBMapTy;
- void *BM;
-
- /// Allocator - The GetValueAtEndOfBlock method uses this BumpPtrAllocator to
- /// hold its internal data. The allocator and its storage is created and
- /// discarded for each invocation of GetValueAtEndOfBlock.
- void *BPA;
+ // 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.
SmallVectorImpl<PHINode*> *InsertedPHIs;
+
public:
/// SSAUpdater constructor. If InsertedPHIs is specified, it will be filled
/// in with all PHI Nodes created by rewriting.
~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);
+ /// 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.
/// for the use's block will be considered to be below it.
void RewriteUse(Use &U);
+ /// RewriteUseAfterInsertions - Rewrite a use, just like RewriteUse. However,
+ /// 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 FindPHIPlacement(BasicBlock *BB, BBInfo *Info, bool &Changed,
- unsigned Counter);
- void FindAvailableVal(BasicBlock *BB, BBInfo *Info, unsigned Counter);
- void FindExistingPHI(BasicBlock *BB, BBInfo *Info);
- bool CheckIfPHIMatches(BasicBlock *BB, BBInfo *Info, Value *Val);
- void RecordMatchingPHI(BasicBlock *BB, BBInfo *Info, PHINode *PHI);
- void ClearPHITags(BasicBlock *BB, BBInfo *Info, PHINode *PHI);
void operator=(const SSAUpdater&); // DO NOT IMPLEMENT
SSAUpdater(const SSAUpdater&); // DO NOT IMPLEMENT
};
+
+/// LoadAndStorePromoter - This little helper class provides a convenient way to
+/// promote 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() {}
+
+ /// run - 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;
+
+
+ /// Return true if the specified instruction is in the Inst list (which was
+ /// passed into the run method). Clients should implement this with a more
+ /// efficient version if possible.
+ virtual bool isInstInList(Instruction *I,
+ const SmallVectorImpl<Instruction*> &Insts) const;
+
+ /// doExtraRewritesBeforeFinalDeletion - This hook is invoked after all the
+ /// stores are found and inserted as available values, but
+ virtual void doExtraRewritesBeforeFinalDeletion() const {
+ }
+
+ /// replaceLoadWithValue - 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 {
+ }
+
+ /// This is called before each instruction is deleted.
+ virtual void instructionDeleted(Instruction *I) const {
+ }
+
+ /// updateDebugInfo - This is called to update debug info associated with the
+ /// instruction.
+ virtual void updateDebugInfo(Instruction *I) const {
+ }
+};
} // End llvm namespace