| // Copyright 2020 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_AST_STRUCT_MEMBER_OFFSET_DECORATION_H_ |
| #define SRC_AST_STRUCT_MEMBER_OFFSET_DECORATION_H_ |
| |
| #include <string> |
| |
| #include "src/ast/decoration.h" |
| |
| namespace tint { |
| namespace ast { |
| |
| /// A struct member offset decoration |
| /// @note The WGSL spec removed the `[[offset(n)]]` decoration for `[[size(n)]]` |
| /// and `[[align(n)]]` in https://github.com/gpuweb/gpuweb/pull/1447. However |
| /// this decoration is kept because the SPIR-V reader has to deal with absolute |
| /// offsets, and transforming these to size / align is complex and can be done |
| /// in a number of ways. The Resolver is responsible for consuming the size and |
| /// align decorations and transforming these into absolute offsets. It is |
| /// trivial for the Resolver to handle `[[offset(n)]]` or `[[size(n)]]` / |
| /// `[[align(n)]]` decorations, so this is what we do, keeping all the layout |
| /// logic in one place. |
| class StructMemberOffsetDecoration |
| : public Castable<StructMemberOffsetDecoration, Decoration> { |
| public: |
| /// constructor |
| /// @param program_id the identifier of the program that owns this node |
| /// @param source the source of this decoration |
| /// @param offset the offset value |
| StructMemberOffsetDecoration(ProgramID program_id, |
| const Source& source, |
| uint32_t offset); |
| ~StructMemberOffsetDecoration() override; |
| |
| /// @returns the offset value |
| uint32_t offset() const { return offset_; } |
| |
| /// @returns the WGSL name for the decoration |
| std::string name() const override; |
| |
| /// Outputs the decoration to the given stream |
| /// @param sem the semantic info for the program |
| /// @param out the stream to write to |
| /// @param indent number of spaces to indent the node when writing |
| void to_str(const sem::Info& sem, |
| std::ostream& out, |
| size_t indent) const override; |
| |
| /// Clones this node and all transitive child nodes using the `CloneContext` |
| /// `ctx`. |
| /// @param ctx the clone context |
| /// @return the newly cloned node |
| StructMemberOffsetDecoration* Clone(CloneContext* ctx) const override; |
| |
| private: |
| uint32_t const offset_; |
| }; |
| |
| } // namespace ast |
| } // namespace tint |
| |
| #endif // SRC_AST_STRUCT_MEMBER_OFFSET_DECORATION_H_ |