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183 lines
8.5 KiB
C
183 lines
8.5 KiB
C
/* IELR's inadequacy annotation list.
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Copyright (C) 2009-2013 Free Software Foundation, Inc.
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This file is part of Bison, the GNU Compiler Compiler.
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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#ifndef ANNOTATION_LIST_H_
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# define ANNOTATION_LIST_H_
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#include <bitsetv.h>
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#include "Sbitset.h"
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#include "InadequacyList.h"
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#include "state.h"
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typedef unsigned int AnnotationIndex;
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/**
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* A node in a list of annotations on a particular LR(0) state. Each
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* annotation records how isocores of that LR(0) state might contribute to an
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* individual inadequacy, which might manifest in a different state. Don't
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* break encapsulation by modifying the fields directly. Use the provided
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* interface functions.
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*/
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typedef struct AnnotationList
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{
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/** The next node in the list or \c NULL if none. */
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struct AnnotationList *next;
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/** The \c InadequacyList node describing how this inadequacy manifests. */
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InadequacyList *inadequacyNode;
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/**
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* List of how the "always", "never", and potential contributions of the
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* inadequacy might be made by isocores of the annotated LR(0) state:
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* - The number of rows is the number of contributions. That is,
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* <tt>AnnotationList::inadequacyNode->contributionCount</tt>.
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* - The token associated with contribution \c i is
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* <tt>InadequacyList__getContributionToken (AnnotationList::inadequacyNode, i)</tt>.
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* - Iff <tt>AnnotationList::contributions[i] = NULL</tt>, contribution
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* \c i is an "always" contribution. That is, for every isocore of the
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* annotated LR(0) state, its core or the core of one its eventual
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* successors will definitely make this contribution to the inadequacy.
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* It may contribute by either:
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* - Creating a shift of contribution <tt>i</tt>'s token in the state
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* that can manifest the inadequacy.
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* - Propagating that token to the lookahead set of contribution
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* <tt>i</tt>'s reduction in the state that can manifest the
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* inadequacy.
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* - Otherwise:
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* - The number of columns in <tt>AnnotationList::contributions[i]</tt>
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* is the number of kernel items in any isocore of the annotated LR(0)
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* state.
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* - Iff <tt>AnnotationList::contributions[i]</tt> is empty, contribution
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* \c i is a "never" contribution. That is, no isocore of the
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* annotated LR(0) state can make this contribution to the inadequacy.
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* - Otherwise, for each bit \c j that is set in
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* <tt>AnnotationList::contributions[i]</tt>, if the token associated
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* with contribution \c i is present in the lookahead set of kernel
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* item \c j of an isocore of the annotated LR(0) state, that isocore
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* will make contribution \c i to the inadequacy by propagating the
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* contribution's token to the lookahead set of the contribution's
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* reduction in the state that can manifest the inadequacy.
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*/
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Sbitset contributions[1];
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} AnnotationList;
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/**
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* \pre
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* - <tt>s != NULL</tt>.
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* - \c follow_kernel_items, \c always_follows, and \c predecessors were
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* computed by \c ielr_compute_auxiliary_tables.
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* - The size of each of \c annotation_lists and \c annotation_counts is
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* \c ::nstates.
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* - If no \c InadequacyList nodes are currently allocated for the
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* parser tables to which \c s belongs, then it is best if
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* <tt>*inadequacy_list_node_count</tt> is zero to avoid overflow.
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* Otherwise, <tt>*inadequacy_list_node_count</tt> has not been
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* modified by any function except
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* \c AnnotationList__compute_from_inadequacies since the invocation
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* of \c AnnotationList__compute_from_inadequacies that constructed
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* the first of the \c InadequacyList nodes currently allocated for
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* those parser tables.
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* \post
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* - <tt>inadequacy_lists[s->number]</tt> now describes all inadequacies that
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* manifest in \c s.
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* - For every state <tt>states[i]</tt>, <tt>annotation_lists[i]</tt> now
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* contains all annotations associated with all inadequacies that manifest
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* in \c s.
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* - <tt>annotation_counts[i]</tt> was incremented by the number of new
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* annotations added to <tt>states[i]</tt>.
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* - <tt>*max_contributionsp</tt> is the higher of:
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* - The maximum number of contributions computed per annotation.
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* - <tt>*max_contributionsp \@pre</tt>.
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* - All memory for all new annotations was allocated on
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* \c annotations_obstackp.
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*/
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void
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AnnotationList__compute_from_inadequacies (
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state *s, bitsetv follow_kernel_items, bitsetv always_follows,
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state ***predecessors, bitset **item_lookahead_sets,
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InadequacyList **inadequacy_lists, AnnotationList **annotation_lists,
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AnnotationIndex *annotation_counts,
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ContributionIndex *max_contributionsp,
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struct obstack *annotations_obstackp,
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InadequacyListNodeCount *inadequacy_list_node_count);
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/**
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* \pre
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* - <tt>self != NULL</tt>.
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* - \c nitems is the number of kernel items in the LR(0) state that every
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* node in the list \c self annotates.
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* \post
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* - A textual representation of all nodes in the list \c self was printed to
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* stderr. \c spaces spaces were printed before each line of the text.
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*/
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void AnnotationList__debug (AnnotationList const *self, size_t nitems,
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int spaces);
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/**
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* \pre
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* - <tt>self != NULL</tt>.
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* - \c nitems is the number of kernel items in the LR(0) state that \c self
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* annotates.
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* - The number of rows in \c lookahead_filter is at least \c nitems, and the
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* number of columns is \c ::ntokens.
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* \post
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* - <tt>lookahead_filter[i][j]</tt> is set iff some annotation in the list
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* \c self lists token \c j in kernel item \c i as a contributor.
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*/
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void AnnotationList__computeLookaheadFilter (AnnotationList const *self,
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size_t nitems,
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bitsetv lookahead_filter);
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/**
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* \pre
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* - <tt>self != NULL</tt>.
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* - \c nitems is the number of kernel items in the LR(0) state that \c self
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* annotates.
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* - \c lookaheads describes the lookahead sets on the kernel items of some
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* isocore of the LR(0) state that \c self annotates. Either:
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* - <tt>lookaheads = NULL</tt> only if the lookahead set on every kernel
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* item is empty.
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* - For any <tt>0 <= i < nitems</tt>, <tt>lookaheads[i]</tt> is either:
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* - \c NULL only if the lookahead set on kernel item \c i is empty.
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* - The (possibly empty) lookahead set on kernel item \c i.
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* \post
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* - If <tt>require_split_stable = false</tt>, \c result = either:
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* - \c ContributionIndex__none iff the state described by \c lookaheads
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* makes none of the contributions in \c self.
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* - The index of the dominating contribution in \c self that is made by
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* that state.
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* - \c ContributionIndex__error_action to indicate that the inadequacy
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* manifests as a conflict and that a syntax error action (because of a
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* %nonassoc) dominates instead.
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* - Otherwise, \c result is the same as if <tt>require_split_stable =
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* false</tt> except that it is also \c ContributionIndex__none if there
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* are contributions made by the state but the dominating contribution is
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* not split-stable. By split-stable, we mean that the dominating
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* contribution cannot change due to loss of one or more potential
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* contributions due to loss of lookaheads due to splitting of the state.
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* - After determining which contributions are actually made by the state,
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* the algorithm for determining which contribution dominates in the
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* conflict is intended to choose exactly the same action as conflicts.c
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* would choose... no matter how crazy conflicts.c's choice is.
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*/
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ContributionIndex
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AnnotationList__computeDominantContribution (AnnotationList const *self,
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size_t nitems, bitset *lookaheads,
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bool require_split_stable);
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#endif /* !ANNOTATION_LIST_H_ */
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