src/transform/simplify_pointers.h

// Copyright 2021 The Tint Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#ifndef SRC_TRANSFORM_SIMPLIFY_POINTERS_H_
#define SRC_TRANSFORM_SIMPLIFY_POINTERS_H_

#include "src/transform/transform.h"

namespace tint {
namespace transform {

/// SimplifyPointers is a Transform that moves all usage of function-scope
/// `let` statements of a pointer type into their places of usage, while also
/// simplifying any chains of address-of or indirections operators.
///
/// Parameters of a pointer type are not adjusted.
///
/// Note: SimplifyPointers does not operate on module-scope `let`s, as these
/// cannot be pointers: https://gpuweb.github.io/gpuweb/wgsl/#module-constants
/// `A module-scope let-declared constant must be of constructible type.`
///
/// @note Depends on the following transforms to have been run first:
/// * Unshadow
class SimplifyPointers : public Castable<SimplifyPointers, Transform> {
 public:
  /// Constructor
  SimplifyPointers();

  /// Destructor
  ~SimplifyPointers() override;

 protected:
  struct State;

  /// Runs the transform using the CloneContext built for transforming a
  /// program. Run() is responsible for calling Clone() on the CloneContext.
  /// @param ctx the CloneContext primed with the input program and
  /// ProgramBuilder
  /// @param inputs optional extra transform-specific input data
  /// @param outputs optional extra transform-specific output data
  void Run(CloneContext& ctx,
           const DataMap& inputs,
           DataMap& outputs) const override;
};

}  // namespace transform
}  // namespace tint

#endif  // SRC_TRANSFORM_SIMPLIFY_POINTERS_H_