| //===- Layout.h -----------------------------------------------------------===// |
| // |
| // 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 |
| // |
| //===----------------------------------------------------------------------===// |
| |
| // Convenience macros for obtaining offsets of members in structs. |
| // |
| // Usage: |
| // |
| // #define FOR_EACH_FOO_FIELD(DO) \ |
| // DO(Ptr, bar) \ |
| // DO(uint32_t, baz) \ |
| // CREATE_LAYOUT_CLASS(Foo, FOR_EACH_FOO_FIELD) |
| // #undef FOR_EACH_FOO_FIELD |
| // |
| // This will generate |
| // |
| // struct FooLayout { |
| // uint32_t barOffset; |
| // uint32_t bazOffset; |
| // uint32_t totalSize; |
| // |
| // FooLayout(size_t wordSize) { |
| // if (wordSize == 8) |
| // init<uint64_t>(); |
| // else { |
| // assert(wordSize == 4); |
| // init<uint32_t>(); |
| // } |
| // } |
| // |
| // private: |
| // template <class Ptr> void init() { |
| // FOR_EACH_FIELD(_INIT_OFFSET); |
| // barOffset = offsetof(Layout<Ptr>, bar); |
| // bazOffset = offsetof(Layout<Ptr>, baz); |
| // totalSize = sizeof(Layout<Ptr>); |
| // } |
| // template <class Ptr> struct Layout { |
| // Ptr bar; |
| // uint32_t baz; |
| // }; |
| // }; |
| |
| #define _OFFSET_FOR_FIELD(_, name) uint32_t name##Offset; |
| #define _INIT_OFFSET(type, name) name##Offset = offsetof(Layout<Ptr>, name); |
| #define _LAYOUT_ENTRY(type, name) type name; |
| |
| #define CREATE_LAYOUT_CLASS(className, FOR_EACH_FIELD) \ |
| struct className##Layout { \ |
| FOR_EACH_FIELD(_OFFSET_FOR_FIELD) \ |
| uint32_t totalSize; \ |
| \ |
| className##Layout(size_t wordSize) { \ |
| if (wordSize == 8) \ |
| init<uint64_t>(); \ |
| else { \ |
| assert(wordSize == 4); \ |
| init<uint32_t>(); \ |
| } \ |
| } \ |
| \ |
| private: \ |
| template <class Ptr> void init() { \ |
| FOR_EACH_FIELD(_INIT_OFFSET); \ |
| totalSize = sizeof(Layout<Ptr>); \ |
| } \ |
| template <class Ptr> struct Layout { \ |
| FOR_EACH_FIELD(_LAYOUT_ENTRY) \ |
| }; \ |
| } |
