PredIteratorCache.h [plain text]
#ifndef LLVM_IR_PREDITERATORCACHE_H
#define LLVM_IR_PREDITERATORCACHE_H
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/IR/CFG.h"
#include "llvm/Support/Allocator.h"
namespace llvm {
class PredIteratorCache {
DenseMap<BasicBlock *, BasicBlock **> BlockToPredsMap;
DenseMap<BasicBlock *, unsigned> BlockToPredCountMap;
BumpPtrAllocator Memory;
private:
BasicBlock **GetPreds(BasicBlock *BB) {
BasicBlock **&Entry = BlockToPredsMap[BB];
if (Entry)
return Entry;
SmallVector<BasicBlock *, 32> PredCache(pred_begin(BB), pred_end(BB));
PredCache.push_back(nullptr);
BlockToPredCountMap[BB] = PredCache.size() - 1;
Entry = Memory.Allocate<BasicBlock *>(PredCache.size());
std::copy(PredCache.begin(), PredCache.end(), Entry);
return Entry;
}
unsigned GetNumPreds(BasicBlock *BB) {
GetPreds(BB);
return BlockToPredCountMap[BB];
}
public:
size_t size(BasicBlock *BB) { return GetNumPreds(BB); }
ArrayRef<BasicBlock *> get(BasicBlock *BB) {
return makeArrayRef(GetPreds(BB), GetNumPreds(BB));
}
void clear() {
BlockToPredsMap.clear();
BlockToPredCountMap.clear();
Memory.Reset();
}
};
}
#endif