1 //===- llvm/ADT/ilist_node_options.h - ilist_node Options -------*- C++ -*-===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 10 #ifndef LLVM_ADT_ILIST_NODE_OPTIONS_H 11 #define LLVM_ADT_ILIST_NODE_OPTIONS_H 12 13 #include "llvm/Config/abi-breaking.h" 14 #include "llvm/Config/llvm-config.h" 15 16 #include <type_traits> 17 18 namespace llvm { 19 20 template <bool EnableSentinelTracking> class ilist_node_base; 21 template <bool EnableSentinelTracking> class ilist_base; 22 23 /// Option to choose whether to track sentinels. 24 /// 25 /// This option affects the ABI for the nodes. When not specified explicitly, 26 /// the ABI depends on LLVM_ENABLE_ABI_BREAKING_CHECKS. Specify explicitly to 27 /// enable \a ilist_node::isSentinel(). 28 template <bool EnableSentinelTracking> struct ilist_sentinel_tracking {}; 29 30 /// Option to specify a tag for the node type. 31 /// 32 /// This option allows a single value type to be inserted in multiple lists 33 /// simultaneously. See \a ilist_node for usage examples. 34 template <class Tag> struct ilist_tag {}; 35 36 namespace ilist_detail { 37 38 /// Helper trait for recording whether an option is specified explicitly. 39 template <bool IsExplicit> struct explicitness { 40 static const bool is_explicit = IsExplicit; 41 }; 42 typedef explicitness<true> is_explicit; 43 typedef explicitness<false> is_implicit; 44 45 /// Check whether an option is valid. 46 /// 47 /// The steps for adding and enabling a new ilist option include: 48 /// \li define the option, ilist_foo<Bar>, above; 49 /// \li add new parameters for Bar to \a ilist_detail::node_options; 50 /// \li add an extraction meta-function, ilist_detail::extract_foo; 51 /// \li call extract_foo from \a ilist_detail::compute_node_options and pass it 52 /// into \a ilist_detail::node_options; and 53 /// \li specialize \c is_valid_option<ilist_foo<Bar>> to inherit from \c 54 /// std::true_type to get static assertions passing in \a simple_ilist and \a 55 /// ilist_node. 56 template <class Option> struct is_valid_option : std::false_type {}; 57 58 /// Extract sentinel tracking option. 59 /// 60 /// Look through \p Options for the \a ilist_sentinel_tracking option, with the 61 /// default depending on LLVM_ENABLE_ABI_BREAKING_CHECKS. 62 template <class... Options> struct extract_sentinel_tracking; 63 template <bool EnableSentinelTracking, class... Options> 64 struct extract_sentinel_tracking< 65 ilist_sentinel_tracking<EnableSentinelTracking>, Options...> 66 : std::integral_constant<bool, EnableSentinelTracking>, is_explicit {}; 67 template <class Option1, class... Options> 68 struct extract_sentinel_tracking<Option1, Options...> 69 : extract_sentinel_tracking<Options...> {}; 70 #if LLVM_ENABLE_ABI_BREAKING_CHECKS 71 template <> struct extract_sentinel_tracking<> : std::true_type, is_implicit {}; 72 #else 73 template <> 74 struct extract_sentinel_tracking<> : std::false_type, is_implicit {}; 75 #endif 76 template <bool EnableSentinelTracking> 77 struct is_valid_option<ilist_sentinel_tracking<EnableSentinelTracking>> 78 : std::true_type {}; 79 80 /// Extract custom tag option. 81 /// 82 /// Look through \p Options for the \a ilist_tag option, pulling out the 83 /// custom tag type, using void as a default. 84 template <class... Options> struct extract_tag; 85 template <class Tag, class... Options> 86 struct extract_tag<ilist_tag<Tag>, Options...> { 87 typedef Tag type; 88 }; 89 template <class Option1, class... Options> 90 struct extract_tag<Option1, Options...> : extract_tag<Options...> {}; 91 template <> struct extract_tag<> { typedef void type; }; 92 template <class Tag> struct is_valid_option<ilist_tag<Tag>> : std::true_type {}; 93 94 /// Check whether options are valid. 95 /// 96 /// The conjunction of \a is_valid_option on each individual option. 97 template <class... Options> struct check_options; 98 template <> struct check_options<> : std::true_type {}; 99 template <class Option1, class... Options> 100 struct check_options<Option1, Options...> 101 : std::integral_constant<bool, is_valid_option<Option1>::value && 102 check_options<Options...>::value> {}; 103 104 /// Traits for options for \a ilist_node. 105 /// 106 /// This is usually computed via \a compute_node_options. 107 template <class T, bool EnableSentinelTracking, bool IsSentinelTrackingExplicit, 108 class TagT> 109 struct node_options { 110 typedef T value_type; 111 typedef T *pointer; 112 typedef T &reference; 113 typedef const T *const_pointer; 114 typedef const T &const_reference; 115 116 static const bool enable_sentinel_tracking = EnableSentinelTracking; 117 static const bool is_sentinel_tracking_explicit = IsSentinelTrackingExplicit; 118 typedef TagT tag; 119 typedef ilist_node_base<enable_sentinel_tracking> node_base_type; 120 typedef ilist_base<enable_sentinel_tracking> list_base_type; 121 }; 122 123 template <class T, class... Options> struct compute_node_options { 124 typedef node_options<T, extract_sentinel_tracking<Options...>::value, 125 extract_sentinel_tracking<Options...>::is_explicit, 126 typename extract_tag<Options...>::type> 127 type; 128 }; 129 130 } // end namespace ilist_detail 131 } // end namespace llvm 132 133 #endif // LLVM_ADT_ILIST_NODE_OPTIONS_H 134
