//===- Utility.h - Collection of geneirc offloading utilities -------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_FRONTEND_OFFLOADING_UTILITY_H
#define LLVM_FRONTEND_OFFLOADING_UTILITY_H

#include "llvm/IR/Module.h"
#include "llvm/Object/OffloadBinary.h"

namespace llvm {
namespace offloading {

/// Offloading entry flags for CUDA / HIP. The first three bits indicate the
/// type of entry while the others are a bit field for additional information.
enum OffloadEntryKindFlag : uint32_t {
  /// Mark the entry as a global entry. This indicates the presense of a
  /// kernel if the size size field is zero and a variable otherwise.
  OffloadGlobalEntry = 0x0,
  /// Mark the entry as a managed global variable.
  OffloadGlobalManagedEntry = 0x1,
  /// Mark the entry as a surface variable.
  OffloadGlobalSurfaceEntry = 0x2,
  /// Mark the entry as a texture variable.
  OffloadGlobalTextureEntry = 0x3,
  /// Mark the entry as being extern.
  OffloadGlobalExtern = 0x1 << 3,
  /// Mark the entry as being constant.
  OffloadGlobalConstant = 0x1 << 4,
  /// Mark the entry as being a normalized surface.
  OffloadGlobalNormalized = 0x1 << 5,
};

/// Returns the type of the offloading entry we use to store kernels and
/// globals that will be registered with the offloading runtime.
StructType *getEntryTy(Module &M);

/// Create an offloading section struct used to register this global at
/// runtime.
///
/// Type struct __tgt_offload_entry {
///   void    *addr;      // Pointer to the offload entry info.
///                       // (function or global)
///   char    *name;      // Name of the function or global.
///   size_t  size;       // Size of the entry info (0 if it a function).
///   int32_t flags;
///   int32_t data;
/// };
///
/// \param M The module to be used
/// \param Addr The pointer to the global being registered.
/// \param Name The symbol name associated with the global.
/// \param Size The size in bytes of the global (0 for functions).
/// \param Flags Flags associated with the entry.
/// \param Data Extra data storage associated with the entry.
/// \param SectionName The section this entry will be placed at.
void emitOffloadingEntry(Module &M, Constant *Addr, StringRef Name,
                         uint64_t Size, int32_t Flags, int32_t Data,
                         StringRef SectionName);
/// Create a constant struct initializer used to register this global at
/// runtime.
/// \return the constant struct and the global variable holding the symbol name.
std::pair<Constant *, GlobalVariable *>
getOffloadingEntryInitializer(Module &M, Constant *Addr, StringRef Name,
                              uint64_t Size, int32_t Flags, int32_t Data);

/// Creates a pair of globals used to iterate the array of offloading entries by
/// accessing the section variables provided by the linker.
std::pair<GlobalVariable *, GlobalVariable *>
getOffloadEntryArray(Module &M, StringRef SectionName);

} // namespace offloading
} // namespace llvm

#endif // LLVM_FRONTEND_OFFLOADING_UTILITY_H