AutoRTFMConstants.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
// WARNING: Any change in these constants will require a re-patch and re-build of LLVM!
 
#ifdef __cplusplus
#include <cstdint>
 
extern "C"
{
#endif
 
// An enumerator of transactional memory validation levels.
// Memory validation is used to detect modification by open-code to memory that was written by a
// transaction. In this situation, aborting the transaction can corrupt memory as the undo will
// overwrite the writes made in the open-code.
typedef enum
{
    // Use the default memory validation level.
    autortfm_memory_validation_level_default,
 
    // Disable memory validation.
    autortfm_memory_validation_level_disabled,
 
    // Enable memory validation. Memory validation failures are treated as warnings.
    autortfm_memory_validation_level_warn,
 
    // Enable memory validation. Memory validation are treated as fatal.
    autortfm_memory_validation_level_error,
} autortfm_memory_validation_level;
 
#ifdef __cplusplus
}
#endif
 
#ifdef __cplusplus
namespace AutoRTFM::Constants
{
    inline constexpr uint32_t Major = 0;
    inline constexpr uint32_t Minor = 2;
    inline constexpr uint32_t Patch = 0;
 
    // The Magic Prefix constant - an arbitrarily chosen address prefix, shared
    // between the AutoRTFM compiler and runtime.
    // We add this prefix value to open function pointer addresses in our custom 
    // LLVM pass. At runtime, if we detect the Magic Prefix in the the top 16 bits
    // of an open function pointer address, we assume that we can find a closed
    // variant pointer residing 8 bytes before the function address.
    inline constexpr uint64_t MagicPrefix = 0xa273'0000'0000'0000;
    // Similar to the above, but these constants indicate that the low 48 bits
    // provide a relative addresses from the open function to the closed
    // function.
    inline constexpr uint64_t PosOffsetMagicPrefix = 0xa272'0000'0000'0000;
    inline constexpr uint64_t NegOffsetMagicPrefix = 0xa271'0000'0000'0000;
 
} // namespace AutoRTFM::Constants
#endif