src/tint/lang/core/ir/transform/direct_variable_access.h

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#ifndef SRC_TINT_LANG_CORE_IR_TRANSFORM_DIRECT_VARIABLE_ACCESS_H_
#define SRC_TINT_LANG_CORE_IR_TRANSFORM_DIRECT_VARIABLE_ACCESS_H_

#include "src/tint/lang/core/ir/validator.h"
#include "src/tint/utils/reflection.h"
#include "src/tint/utils/result.h"

// Forward declarations.
namespace tint::core::ir {
class Module;
}

namespace tint::core::ir::transform {

/// The capabilities that the transform can support.
const core::ir::Capabilities kDirectVariableAccessCapabilities{
    core::ir::Capability::kAllowClipDistancesOnF32, core::ir::Capability::kAllowDuplicateBindings};

/// DirectVariableAccessOptions adjusts the behaviour of the transform.
struct DirectVariableAccessOptions {
    /// If true, then 'private' sub-object pointer arguments will be transformed.
    bool transform_private = false;
    /// If true, then 'function' sub-object pointer arguments will be transformed.
    bool transform_function = false;
    /// If true, then 'handle' sub-object handle type arguments will be transformed.
    bool transform_handle = false;

    /// Reflection for this class
    TINT_REFLECT(DirectVariableAccessOptions,
                 transform_private,
                 transform_function,
                 transform_handle);
};

/// DirectVariableAccess is a transform that transforms parameters in the 'storage',
/// 'uniform' and 'workgroup' address space so that they're accessed directly by the function,
/// instead of being passed by pointer. It will potentially also transform `private`, `handle` or
/// `function` parameters depending on provided options.
///
/// DirectVariableAccess works by creating specializations of functions that have matching
/// parameters, one specialization for each argument's unique access chain 'shape' from a unique
/// variable. Calls to specialized functions are transformed so that the arguments are replaced with
/// an array of access-chain indices, and if the parameter is in the 'function' or 'private'
/// address space, also with a pointer to the root object.
///
/// @param module the module to transform
/// @param options the options
/// @returns error on failure
Result<SuccessType> DirectVariableAccess(Module& module,
                                         const DirectVariableAccessOptions& options);

}  // namespace tint::core::ir::transform

#endif  // SRC_TINT_LANG_CORE_IR_TRANSFORM_DIRECT_VARIABLE_ACCESS_H_