LLVM  8.0.0svn
ilist_node_options.h
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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 
15 #include <type_traits>
16 
17 namespace llvm {
18 
19 template <bool EnableSentinelTracking> class ilist_node_base;
20 template <bool EnableSentinelTracking> class ilist_base;
21 
22 /// Option to choose whether to track sentinels.
23 ///
24 /// This option affects the ABI for the nodes. When not specified explicitly,
25 /// the ABI depends on LLVM_ENABLE_ABI_BREAKING_CHECKS. Specify explicitly to
26 /// enable \a ilist_node::isSentinel().
27 template <bool EnableSentinelTracking> struct ilist_sentinel_tracking {};
28 
29 /// Option to specify a tag for the node type.
30 ///
31 /// This option allows a single value type to be inserted in multiple lists
32 /// simultaneously. See \a ilist_node for usage examples.
33 template <class Tag> struct ilist_tag {};
34 
35 namespace ilist_detail {
36 
37 /// Helper trait for recording whether an option is specified explicitly.
38 template <bool IsExplicit> struct explicitness {
39  static const bool is_explicit = IsExplicit;
40 };
43 
44 /// Check whether an option is valid.
45 ///
46 /// The steps for adding and enabling a new ilist option include:
47 /// \li define the option, ilist_foo<Bar>, above;
48 /// \li add new parameters for Bar to \a ilist_detail::node_options;
49 /// \li add an extraction meta-function, ilist_detail::extract_foo;
50 /// \li call extract_foo from \a ilist_detail::compute_node_options and pass it
51 /// into \a ilist_detail::node_options; and
52 /// \li specialize \c is_valid_option<ilist_foo<Bar>> to inherit from \c
53 /// std::true_type to get static assertions passing in \a simple_ilist and \a
54 /// ilist_node.
55 template <class Option> struct is_valid_option : std::false_type {};
56 
57 /// Extract sentinel tracking option.
58 ///
59 /// Look through \p Options for the \a ilist_sentinel_tracking option, with the
60 /// default depending on LLVM_ENABLE_ABI_BREAKING_CHECKS.
61 template <class... Options> struct extract_sentinel_tracking;
62 template <bool EnableSentinelTracking, class... Options>
64  ilist_sentinel_tracking<EnableSentinelTracking>, Options...>
65  : std::integral_constant<bool, EnableSentinelTracking>, is_explicit {};
66 template <class Option1, class... Options>
67 struct extract_sentinel_tracking<Option1, Options...>
68  : extract_sentinel_tracking<Options...> {};
69 #if LLVM_ENABLE_ABI_BREAKING_CHECKS
70 template <> struct extract_sentinel_tracking<> : std::true_type, is_implicit {};
71 #else
72 template <>
73 struct extract_sentinel_tracking<> : std::false_type, is_implicit {};
74 #endif
75 template <bool EnableSentinelTracking>
76 struct is_valid_option<ilist_sentinel_tracking<EnableSentinelTracking>>
77  : std::true_type {};
78 
79 /// Extract custom tag option.
80 ///
81 /// Look through \p Options for the \a ilist_tag option, pulling out the
82 /// custom tag type, using void as a default.
83 template <class... Options> struct extract_tag;
84 template <class Tag, class... Options>
85 struct extract_tag<ilist_tag<Tag>, Options...> {
86  typedef Tag type;
87 };
88 template <class Option1, class... Options>
89 struct extract_tag<Option1, Options...> : extract_tag<Options...> {};
90 template <> struct extract_tag<> { typedef void type; };
91 template <class Tag> struct is_valid_option<ilist_tag<Tag>> : std::true_type {};
92 
93 /// Check whether options are valid.
94 ///
95 /// The conjunction of \a is_valid_option on each individual option.
96 template <class... Options> struct check_options;
97 template <> struct check_options<> : std::true_type {};
98 template <class Option1, class... Options>
99 struct check_options<Option1, Options...>
100  : std::integral_constant<bool, is_valid_option<Option1>::value &&
101  check_options<Options...>::value> {};
102 
103 /// Traits for options for \a ilist_node.
104 ///
105 /// This is usually computed via \a compute_node_options.
106 template <class T, bool EnableSentinelTracking, bool IsSentinelTrackingExplicit,
107  class TagT>
108 struct node_options {
109  typedef T value_type;
110  typedef T *pointer;
111  typedef T &reference;
112  typedef const T *const_pointer;
113  typedef const T &const_reference;
114 
115  static const bool enable_sentinel_tracking = EnableSentinelTracking;
116  static const bool is_sentinel_tracking_explicit = IsSentinelTrackingExplicit;
117  typedef TagT tag;
120 };
121 
122 template <class T, class... Options> struct compute_node_options {
123  typedef node_options<T, extract_sentinel_tracking<Options...>::value,
125  typename extract_tag<Options...>::type>
127 };
128 
129 } // end namespace ilist_detail
130 } // end namespace llvm
131 
132 #endif // LLVM_ADT_ILIST_NODE_OPTIONS_H
Check whether an option is valid.
Compute iterated dominance frontiers using a linear time algorithm.
Definition: AllocatorList.h:24
explicitness< false > is_implicit
node_options< T, extract_sentinel_tracking< Options... >::value, extract_sentinel_tracking< Options... >::is_explicit, typename extract_tag< Options... >::type > type
explicitness< true > is_explicit
#define T
Extract sentinel tracking option.
Base class for ilist nodes.
Option to choose whether to track sentinels.
ilist_node_base< enable_sentinel_tracking > node_base_type
Check whether options are valid.
Option to specify a tag for the node type.
ilist_base< enable_sentinel_tracking > list_base_type
Helper trait for recording whether an option is specified explicitly.
Implementations of list algorithms using ilist_node_base.
Definition: ilist_base.h:19
Extract custom tag option.
Traits for options for ilist_node.