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1 /* IELR's inadequacy annotation list.
2
3 Copyright (C) 2009-2013 Free Software Foundation, Inc.
4
5 This file is part of Bison, the GNU Compiler Compiler.
6
7 This program is free software: you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation, either version 3 of the License, or
10 (at your option) any later version.
11
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
16
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
19
20 #ifndef ANNOTATION_LIST_H_
21 # define ANNOTATION_LIST_H_
22
23 # include <bitsetv.h>
24 # include "Sbitset.h"
25 # include "InadequacyList.h"
26 # include "state.h"
27
28 typedef unsigned int AnnotationIndex;
29
30 /**
31 * A node in a list of annotations on a particular LR(0) state. Each
32 * annotation records how isocores of that LR(0) state might contribute to an
33 * individual inadequacy, which might manifest in a different state. Don't
34 * break encapsulation by modifying the fields directly. Use the provided
35 * interface functions.
36 */
37 typedef struct AnnotationList
38 {
39 /** The next node in the list or \c NULL if none. */
40 struct AnnotationList *next;
41 /** The \c InadequacyList node describing how this inadequacy manifests. */
42 InadequacyList *inadequacyNode;
43 /**
44 * List of how the "always", "never", and potential contributions of the
45 * inadequacy might be made by isocores of the annotated LR(0) state:
46 * - The number of rows is the number of contributions. That is,
47 * <tt>AnnotationList::inadequacyNode->contributionCount</tt>.
48 * - The token associated with contribution \c i is
49 * <tt>InadequacyList__getContributionToken (AnnotationList::inadequacyNode, i)</tt>.
50 * - Iff <tt>AnnotationList::contributions[i] = NULL</tt>, contribution
51 * \c i is an "always" contribution. That is, for every isocore of the
52 * annotated LR(0) state, its core or the core of one its eventual
53 * successors will definitely make this contribution to the inadequacy.
54 * It may contribute by either:
55 * - Creating a shift of contribution <tt>i</tt>'s token in the state
56 * that can manifest the inadequacy.
57 * - Propagating that token to the lookahead set of contribution
58 * <tt>i</tt>'s reduction in the state that can manifest the
59 * inadequacy.
60 * - Otherwise:
61 * - The number of columns in <tt>AnnotationList::contributions[i]</tt>
62 * is the number of kernel items in any isocore of the annotated LR(0)
63 * state.
64 * - Iff <tt>AnnotationList::contributions[i]</tt> is empty, contribution
65 * \c i is a "never" contribution. That is, no isocore of the
66 * annotated LR(0) state can make this contribution to the inadequacy.
67 * - Otherwise, for each bit \c j that is set in
68 * <tt>AnnotationList::contributions[i]</tt>, if the token associated
69 * with contribution \c i is present in the lookahead set of kernel
70 * item \c j of an isocore of the annotated LR(0) state, that isocore
71 * will make contribution \c i to the inadequacy by propagating the
72 * contribution's token to the lookahead set of the contribution's
73 * reduction in the state that can manifest the inadequacy.
74 */
75 Sbitset contributions[1];
76 } AnnotationList;
77
78 /**
79 * \pre
80 * - <tt>s != NULL</tt>.
81 * - \c follow_kernel_items, \c always_follows, and \c predecessors were
82 * computed by \c ielr_compute_auxiliary_tables.
83 * - The size of each of \c annotation_lists and \c annotation_counts is
84 * \c ::nstates.
85 * - If no \c InadequacyList nodes are currently allocated for the
86 * parser tables to which \c s belongs, then it is best if
87 * <tt>*inadequacy_list_node_count</tt> is zero to avoid overflow.
88 * Otherwise, <tt>*inadequacy_list_node_count</tt> has not been
89 * modified by any function except
90 * \c AnnotationList__compute_from_inadequacies since the invocation
91 * of \c AnnotationList__compute_from_inadequacies that constructed
92 * the first of the \c InadequacyList nodes currently allocated for
93 * those parser tables.
94 * \post
95 * - <tt>inadequacy_lists[s->number]</tt> now describes all inadequacies that
96 * manifest in \c s.
97 * - For every state <tt>states[i]</tt>, <tt>annotation_lists[i]</tt> now
98 * contains all annotations associated with all inadequacies that manifest
99 * in \c s.
100 * - <tt>annotation_counts[i]</tt> was incremented by the number of new
101 * annotations added to <tt>states[i]</tt>.
102 * - <tt>*max_contributionsp</tt> is the higher of:
103 * - The maximum number of contributions computed per annotation.
104 * - <tt>*max_contributionsp \@pre</tt>.
105 * - All memory for all new annotations was allocated on
106 * \c annotations_obstackp.
107 */
108 void
109 AnnotationList__compute_from_inadequacies (
110 state *s, bitsetv follow_kernel_items, bitsetv always_follows,
111 state ***predecessors, bitset **item_lookahead_sets,
112 InadequacyList **inadequacy_lists, AnnotationList **annotation_lists,
113 AnnotationIndex *annotation_counts,
114 ContributionIndex *max_contributionsp,
115 struct obstack *annotations_obstackp,
116 InadequacyListNodeCount *inadequacy_list_node_count);
117
118 /**
119 * \pre
120 * - <tt>self != NULL</tt>.
121 * - \c nitems is the number of kernel items in the LR(0) state that every
122 * node in the list \c self annotates.
123 * \post
124 * - A textual representation of all nodes in the list \c self was printed to
125 * stderr. \c spaces spaces were printed before each line of the text.
126 */
127 void AnnotationList__debug (AnnotationList const *self, size_t nitems,
128 int spaces);
129
130 /**
131 * \pre
132 * - <tt>self != NULL</tt>.
133 * - \c nitems is the number of kernel items in the LR(0) state that \c self
134 * annotates.
135 * - The number of rows in \c lookahead_filter is at least \c nitems, and the
136 * number of columns is \c ::ntokens.
137 * \post
138 * - <tt>lookahead_filter[i][j]</tt> is set iff some annotation in the list
139 * \c self lists token \c j in kernel item \c i as a contributor.
140 */
141 void AnnotationList__computeLookaheadFilter (AnnotationList const *self,
142 size_t nitems,
143 bitsetv lookahead_filter);
144
145 /**
146 * \pre
147 * - <tt>self != NULL</tt>.
148 * - \c nitems is the number of kernel items in the LR(0) state that \c self
149 * annotates.
150 * - \c lookaheads describes the lookahead sets on the kernel items of some
151 * isocore of the LR(0) state that \c self annotates. Either:
152 * - <tt>lookaheads = NULL</tt> only if the lookahead set on every kernel
153 * item is empty.
154 * - For any <tt>0 <= i < nitems</tt>, <tt>lookaheads[i]</tt> is either:
155 * - \c NULL only if the lookahead set on kernel item \c i is empty.
156 * - The (possibly empty) lookahead set on kernel item \c i.
157 * \post
158 * - If <tt>require_split_stable = false</tt>, \c result = either:
159 * - \c ContributionIndex__none iff the state described by \c lookaheads
160 * makes none of the contributions in \c self.
161 * - The index of the dominating contribution in \c self that is made by
162 * that state.
163 * - \c ContributionIndex__error_action to indicate that the inadequacy
164 * manifests as a conflict and that a syntax error action (because of a
165 * %nonassoc) dominates instead.
166 * - Otherwise, \c result is the same as if <tt>require_split_stable =
167 * false</tt> except that it is also \c ContributionIndex__none if there
168 * are contributions made by the state but the dominating contribution is
169 * not split-stable. By split-stable, we mean that the dominating
170 * contribution cannot change due to loss of one or more potential
171 * contributions due to loss of lookaheads due to splitting of the state.
172 * - After determining which contributions are actually made by the state,
173 * the algorithm for determining which contribution dominates in the
174 * conflict is intended to choose exactly the same action as conflicts.c
175 * would choose... no matter how crazy conflicts.c's choice is.
176 */
177 ContributionIndex
178 AnnotationList__computeDominantContribution (AnnotationList const *self,
179 size_t nitems, bitset *lookaheads,
180 bool require_split_stable);
181
182 #endif /* !ANNOTATION_LIST_H_ */