1*06c3fb27SDimitry Andric //===- Layout.h -----------------------------------------------------------===// 2*06c3fb27SDimitry Andric // 3*06c3fb27SDimitry Andric // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4*06c3fb27SDimitry Andric // See https://llvm.org/LICENSE.txt for license information. 5*06c3fb27SDimitry Andric // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6*06c3fb27SDimitry Andric // 7*06c3fb27SDimitry Andric //===----------------------------------------------------------------------===// 8*06c3fb27SDimitry Andric 9*06c3fb27SDimitry Andric // Convenience macros for obtaining offsets of members in structs. 10*06c3fb27SDimitry Andric // 11*06c3fb27SDimitry Andric // Usage: 12*06c3fb27SDimitry Andric // 13*06c3fb27SDimitry Andric // #define FOR_EACH_FOO_FIELD(DO) \ 14*06c3fb27SDimitry Andric // DO(Ptr, bar) \ 15*06c3fb27SDimitry Andric // DO(uint32_t, baz) \ 16*06c3fb27SDimitry Andric // CREATE_LAYOUT_CLASS(Foo, FOR_EACH_FOO_FIELD) 17*06c3fb27SDimitry Andric // #undef FOR_EACH_FOO_FIELD 18*06c3fb27SDimitry Andric // 19*06c3fb27SDimitry Andric // This will generate 20*06c3fb27SDimitry Andric // 21*06c3fb27SDimitry Andric // struct FooLayout { 22*06c3fb27SDimitry Andric // uint32_t barOffset; 23*06c3fb27SDimitry Andric // uint32_t bazOffset; 24*06c3fb27SDimitry Andric // uint32_t totalSize; 25*06c3fb27SDimitry Andric // 26*06c3fb27SDimitry Andric // FooLayout(size_t wordSize) { 27*06c3fb27SDimitry Andric // if (wordSize == 8) 28*06c3fb27SDimitry Andric // init<uint64_t>(); 29*06c3fb27SDimitry Andric // else { 30*06c3fb27SDimitry Andric // assert(wordSize == 4); 31*06c3fb27SDimitry Andric // init<uint32_t>(); 32*06c3fb27SDimitry Andric // } 33*06c3fb27SDimitry Andric // } 34*06c3fb27SDimitry Andric // 35*06c3fb27SDimitry Andric // private: 36*06c3fb27SDimitry Andric // template <class Ptr> void init() { 37*06c3fb27SDimitry Andric // FOR_EACH_FIELD(_INIT_OFFSET); 38*06c3fb27SDimitry Andric // barOffset = offsetof(Layout<Ptr>, bar); 39*06c3fb27SDimitry Andric // bazOffset = offsetof(Layout<Ptr>, baz); 40*06c3fb27SDimitry Andric // totalSize = sizeof(Layout<Ptr>); 41*06c3fb27SDimitry Andric // } 42*06c3fb27SDimitry Andric // template <class Ptr> struct Layout { 43*06c3fb27SDimitry Andric // Ptr bar; 44*06c3fb27SDimitry Andric // uint32_t baz; 45*06c3fb27SDimitry Andric // }; 46*06c3fb27SDimitry Andric // }; 47*06c3fb27SDimitry Andric 48*06c3fb27SDimitry Andric #define _OFFSET_FOR_FIELD(_, name) uint32_t name##Offset; 49*06c3fb27SDimitry Andric #define _INIT_OFFSET(type, name) name##Offset = offsetof(Layout<Ptr>, name); 50*06c3fb27SDimitry Andric #define _LAYOUT_ENTRY(type, name) type name; 51*06c3fb27SDimitry Andric 52*06c3fb27SDimitry Andric #define CREATE_LAYOUT_CLASS(className, FOR_EACH_FIELD) \ 53*06c3fb27SDimitry Andric struct className##Layout { \ 54*06c3fb27SDimitry Andric FOR_EACH_FIELD(_OFFSET_FOR_FIELD) \ 55*06c3fb27SDimitry Andric uint32_t totalSize; \ 56*06c3fb27SDimitry Andric \ 57*06c3fb27SDimitry Andric className##Layout(size_t wordSize) { \ 58*06c3fb27SDimitry Andric if (wordSize == 8) \ 59*06c3fb27SDimitry Andric init<uint64_t>(); \ 60*06c3fb27SDimitry Andric else { \ 61*06c3fb27SDimitry Andric assert(wordSize == 4); \ 62*06c3fb27SDimitry Andric init<uint32_t>(); \ 63*06c3fb27SDimitry Andric } \ 64*06c3fb27SDimitry Andric } \ 65*06c3fb27SDimitry Andric \ 66*06c3fb27SDimitry Andric private: \ 67*06c3fb27SDimitry Andric template <class Ptr> void init() { \ 68*06c3fb27SDimitry Andric FOR_EACH_FIELD(_INIT_OFFSET); \ 69*06c3fb27SDimitry Andric totalSize = sizeof(Layout<Ptr>); \ 70*06c3fb27SDimitry Andric } \ 71*06c3fb27SDimitry Andric template <class Ptr> struct Layout { \ 72*06c3fb27SDimitry Andric FOR_EACH_FIELD(_LAYOUT_ENTRY) \ 73*06c3fb27SDimitry Andric }; \ 74*06c3fb27SDimitry Andric } 75