Hashing.hpp

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#ifndef PROTEUS_HASHING_HPP
#define PROTEUS_HASHING_HPP
 
#include "proteus/CompilerInterfaceTypes.h"
#include "proteus/RuntimeConstantTypeHelpers.h"
#include "proteus/TimeTracing.hpp"
 
#include <llvm/ADT/ArrayRef.h>
#if LLVM_VERSION_MAJOR >= 18
#include <llvm/ADT/StableHashing.h>
#else
#include <llvm/CodeGen/StableHashing.h>
#endif
 
#include <string>
 
namespace proteus {
 
using namespace llvm;
 
class HashT {
private:
  stable_hash Value;
 
public:
  inline HashT(const stable_hash HashValue) { Value = HashValue; }
  inline HashT(const StringRef &S) { S.getAsInteger(0, Value); }
  inline stable_hash getValue() const { return Value; }
  inline std::string toString() const { return std::to_string(Value); }
  inline bool operator==(const HashT &Other) const {
    return Value == Other.Value;
  }
 
  inline bool operator<(const HashT &Other) const {
    return Value < Other.Value;
  }
};
 
inline HashT hashValue(const HashT &H) { return H; }
 
// Function that abstracts interface differences in stable hashing across LLVM.
inline HashT hashValue(const StringRef &S) {
#if LLVM_VERSION_MAJOR >= 20
  ArrayRef<uint8_t> Bytes(reinterpret_cast<const uint8_t *>(S.data()),
                          S.size());
  return xxh3_64bits(Bytes);
#else
  return stable_hash_combine_string(S);
#endif
}
 
inline HashT hashValue(const std::string &S) { return hashValue(StringRef{S}); }
 
template <typename T>
inline std::enable_if_t<std::is_scalar<T>::value, HashT> hashValue(const T &V) {
  return hashValue(StringRef{reinterpret_cast<const char *>(&V), sizeof(T)});
}
 
template <typename T>
inline HashT hashRuntimeConstantArray(const RuntimeConstant &RC) {
  if (RC.ArrInfo.NumElts <= 0)
    reportFatalError("Invalid number of elements in array: " +
                     std::to_string(RC.ArrInfo.NumElts));
 
  if (!RC.ArrInfo.Blob)
    reportFatalError("Expected non-null Blob");
 
  return hashValue(
      StringRef{reinterpret_cast<const char *>(RC.ArrInfo.Blob.get()),
                sizeof(T) * RC.ArrInfo.NumElts});
}
 
inline HashT hashRuntimeConstantObject(const RuntimeConstant &RC) {
  if (RC.ObjInfo.Size <= 0)
    reportFatalError("Invalid object size <= 0");
 
  if (!RC.ObjInfo.Blob)
    reportFatalError("Expected non-null Blob");
 
  return hashValue(
      StringRef{reinterpret_cast<const char *>(RC.ObjInfo.Blob.get()),
                static_cast<size_t>(RC.ObjInfo.Size)});
}
 
inline HashT hashArrayRefElement(const RuntimeConstant &RC) {
  if (RC.Type == RuntimeConstantType::ARRAY ||
      RC.Type == RuntimeConstantType::STATIC_ARRAY ||
      RC.Type == RuntimeConstantType::VECTOR) {
    switch (RC.ArrInfo.EltType) {
    case RuntimeConstantType::BOOL:
      return hashRuntimeConstantArray<bool>(RC);
    case RuntimeConstantType::INT8:
      return hashRuntimeConstantArray<int8_t>(RC);
    case RuntimeConstantType::INT32:
      return hashRuntimeConstantArray<int32_t>(RC);
    case RuntimeConstantType::INT64:
      return hashRuntimeConstantArray<int64_t>(RC);
    case RuntimeConstantType::FLOAT:
      return hashRuntimeConstantArray<float>(RC);
    case RuntimeConstantType::DOUBLE:
      return hashRuntimeConstantArray<double>(RC);
    default:
      reportFatalError("Unsupported array element type: " +
                       toString(RC.ArrInfo.EltType));
    }
  } else if (RC.Type == RuntimeConstantType::OBJECT) {
    return hashRuntimeConstantObject(RC);
  } else if (isScalarRuntimeConstantType(RC.Type)) {
    return hashValue(
        StringRef{reinterpret_cast<const char *>(&RC.Value), sizeof(RC.Value)});
  }
 
  reportFatalError("Unsupported type " + toString(RC.Type));
}
 
inline HashT hashValue(ArrayRef<RuntimeConstant> Arr) {
  if (Arr.empty())
    return 0;
 
  HashT HashValue = hashArrayRefElement(Arr[0]);
  for (int I = 1, E = Arr.size(); I < E; ++I)
    HashValue = stable_hash_combine(HashValue.getValue(),
                                    hashArrayRefElement(Arr[I]).getValue());
 
  return HashValue;
}
 
inline HashT hashCombine(HashT A, HashT B) {
  return stable_hash_combine(A.getValue(), B.getValue());
}
 
template <typename FirstT, typename... RestTs>
inline HashT hash(FirstT &&First, RestTs &&...Rest) {
  TIMESCOPE(__FUNCTION__);
  HashT HashValue = hashValue(First);
 
  ((HashValue = hashCombine(HashValue, hashValue(Rest))), ...);
 
  return HashValue;
}
 
template <typename T> inline HashT hash(T &&Data) {
  HashT HashValue = hashValue(Data);
  return HashValue;
}
 
} // namespace proteus
 
namespace std {
template <> struct hash<proteus::HashT> {
  std::size_t operator()(const proteus::HashT &Key) const {
    return Key.getValue();
  }
};
 
} // namespace std
#endif