1 /* Bison code properties structure and scanner.
2
3 Copyright (C) 2006-2007, 2009-2015, 2018-2021 Free Software
4 Foundation, Inc.
5
6 This file is part of Bison, the GNU Compiler Compiler.
7
8 This program is free software: you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation, either version 3 of the License, or
11 (at your option) any later version.
12
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
17
18 You should have received a copy of the GNU General Public License
19 along with this program. If not, see <https://www.gnu.org/licenses/>. */
20
21 #ifndef SCAN_CODE_H_
22 # define SCAN_CODE_H_
23
24 # include "location.h"
25 # include "named-ref.h"
26 # include "uniqstr.h"
27
28 struct symbol_list;
29
30 /**
31 * Keeps track of the maximum number of semantic values to the left of a handle
32 * (those referenced by $0, $-1, etc.) that are required by the semantic
33 * actions of this grammar.
34 */
35 extern int max_left_semantic_context;
36
37 /**
38 * The obstack used to store the translated actions.
39 */
40 extern struct obstack *obstack_for_actions;
41
42 /**
43 * A code passage captured from the grammar file and possibly translated,
44 * and/or properties associated with such a code passage. Don't break
45 * encapsulation by modifying the fields directly. Use the provided interface
46 * functions.
47 */
48 typedef struct code_props {
49 /** Set by the init functions. */
50 enum {
51 CODE_PROPS_NONE, CODE_PROPS_PLAIN,
52 CODE_PROPS_SYMBOL_ACTION, CODE_PROPS_RULE_ACTION
53 } kind;
54
55 /**
56 * \c NULL iff \c code_props::kind is \c CODE_PROPS_NONE.
57 * Memory is allocated in an obstack freed elsewhere.
58 */
59 char const *code;
60 /** Undefined iff \c code_props::code is \c NULL. */
61 location location;
62
63 /**
64 * \c false iff either:
65 * - \c code_props_translate_code has never previously been invoked for
66 * the \c code_props that would contain the code passage associated
67 * with \c self. (That \c code_props is not the same as this one if this
68 * one is for a RHS \c symbol_list node. Instead, it's the \c code_props
69 * for the LHS symbol of the same rule.)
70 * - \c code_props_translate_code has been invoked for that \c code_props,
71 * but the symbol value associated with this \c code_props was not
72 * referenced in the code passage.
73 */
74 bool is_value_used;
75
76 /**
77 * \c true iff this code is an action that is not to be deferred in
78 * a non-deterministic parser.
79 */
80 bool is_predicate;
81
82 /**
83 * Whether this is actually used (i.e., not completely masked by
84 * other code props). */
85 bool is_used;
86
87 /** \c NULL iff \c code_props::kind is not \c CODE_PROPS_RULE_ACTION. */
88 struct symbol_list *rule;
89
90 /** Named reference. */
91 named_ref *named_ref;
92
93 /** Type, for midrule actions. */
94 uniqstr type;
95 } code_props;
96
97 /**
98 * \pre
99 * - <tt>self != NULL</tt>.
100 * \post
101 * - \c self has been overwritten to contain no code.
102 */
103 void code_props_none_init (code_props *self);
104
105 /** Equivalent to \c code_props_none_init. */
106 # define CODE_PROPS_NONE_INIT \
107 { \
108 /* .kind = */ CODE_PROPS_NONE, \
109 /* .code = */ NULL, \
110 /* .location = */ EMPTY_LOCATION_INIT, \
111 /* .is_value_used = */ false, \
112 /* .is_predicate = */ false, \
113 /* .is_used = */ false, \
114 /* .rule = */ NULL, \
115 /* .named_ref = */ NULL, \
116 /* .type = */ NULL, \
117 }
118
119 /** Initialized by \c CODE_PROPS_NONE_INIT with no further modification. */
120 extern code_props code_props_none;
121
122 /**
123 * \pre
124 * - <tt>self != NULL</tt>.
125 * - <tt>code != NULL</tt>.
126 * - \c code is an untranslated code passage containing no Bison escapes.
127 * - \c code was extracted from the grammar file at \c code_loc.
128 * \post
129 * - \c self has been overwritten to represent the specified plain code
130 * passage.
131 * - \c self will become invalid if the caller frees \c code before invoking
132 * \c code_props_translate_code on \c self.
133 */
134 void code_props_plain_init (code_props *self, char const *code,
135 location code_loc);
136
137 /**
138 * \pre
139 * - <tt>self != NULL</tt>.
140 * - <tt>code != NULL</tt>.
141 * - \c code is an untranslated code passage. The only Bison escapes it
142 * might contain are $$ and \@$, referring to a single symbol.
143 * - \c code was extracted from the grammar file at \c code_loc.
144 * \post
145 * - \c self has been overwritten to represent the specified symbol action.
146 * - \c self will become invalid if the caller frees \c code before invoking
147 * \c code_props_translate_code on \c self.
148 */
149 void code_props_symbol_action_init (code_props *self, char const *code,
150 location code_loc);
151
152 /**
153 * \param type type for midrule actions
154 * \pre
155 * - <tt>self != NULL</tt>.
156 * - <tt>code != NULL</tt>.
157 * - <tt>rule != NULL</tt>.
158 * - \c code is the untranslated action of the rule for which \c rule is the
159 * LHS node. Thus, \c code possibly contains Bison escapes such as $$, $1,
160 * $2, etc referring to the values of the rule.
161 * - \c code was extracted from the grammar file at \c code_loc.
162 * \post
163 * - \c self has been overwritten to represent the specified rule action.
164 * - \c self does not claim responsibility for the memory of \c rule.
165 * - \c self will become invalid if:
166 * - The caller frees \c code before invoking \c code_props_translate_code
167 * on \c self.
168 * - The caller frees \c rule.
169 */
170 void code_props_rule_action_init (code_props *self, char const *code,
171 location code_loc, struct symbol_list *rule,
172 named_ref *name, uniqstr type,
173 bool is_predicate);
174
175 /**
176 * \pre
177 * - If there's a code passage contained in \c self and it contains Bison
178 * escapes, all grammar declarations have already been parsed as they may
179 * affect warnings and complaints issued here.
180 * \post
181 * - All M4-special symbols and Bison escapes have been translated in
182 * \c self->code.
183 * - <tt>self->code != self->code\@pre</tt> unless
184 * <tt>self->code\@pre = NULL</tt>.
185 */
186 void code_props_translate_code (code_props *self);
187
188 /**
189 * \pre
190 * - None.
191 * \post
192 * - The dynamic memory allocated by the previous invocation of
193 * \c code_props_translate_code (if any) was freed. The \c code_props
194 * instance for which \c code_props_translate_code was invoked is now
195 * invalid.
196 */
197 void code_scanner_last_string_free (void);
198
199 void code_scanner_init (void);
200
201 /**
202 * \pre
203 * - None.
204 * \post
205 * - All dynamic memory allocated during invocations of
206 * \c code_props_translate_code (if any) has been freed. All \c code_props
207 * instances may now be invalid.
208 */
209 void code_scanner_free (void);
210
211 #endif /* !SCAN_CODE_H_ */