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1 | /* Bison Action Scanner -*- C -*- | |
2 | ||
3 | Copyright (C) 2006, 2007 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 | %option debug nodefault nounput noyywrap never-interactive | |
21 | %option prefix="code_" outfile="lex.yy.c" | |
22 | ||
23 | %{ | |
24 | /* Work around a bug in flex 2.5.31. See Debian bug 333231 | |
25 | <http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=333231>. */ | |
26 | #undef code_wrap | |
27 | #define code_wrap() 1 | |
28 | ||
29 | #define FLEX_PREFIX(Id) code_ ## Id | |
30 | #include "flex-scanner.h" | |
31 | ||
32 | #include "complain.h" | |
33 | #include "reader.h" | |
34 | #include "getargs.h" | |
35 | #include <get-errno.h> | |
36 | #include <quote.h> | |
37 | ||
38 | #include "scan-code.h" | |
39 | #include "symlist.h" | |
40 | ||
41 | /* The current calling start condition: SC_RULE_ACTION or | |
42 | SC_SYMBOL_ACTION. */ | |
43 | # define YY_DECL static char *code_lex (code_props *self, int sc_context) | |
44 | YY_DECL; | |
45 | ||
46 | #define YY_USER_ACTION location_compute (loc, &loc->end, yytext, yyleng); | |
47 | ||
48 | static void handle_action_dollar (symbol_list *rule, char *cp, | |
49 | location dollar_loc); | |
50 | static void handle_action_at (symbol_list *rule, char *cp, location at_loc); | |
51 | static location the_location; | |
52 | static location *loc = &the_location; | |
53 | ||
54 | /* A string representing the most recent translation. */ | |
55 | static char *last_string; | |
56 | ||
57 | /* True if an untyped $$ or $n was seen. */ | |
58 | static bool untyped_var_seen; | |
59 | %} | |
60 | /* C and C++ comments in code. */ | |
61 | %x SC_COMMENT SC_LINE_COMMENT | |
62 | /* Strings and characters in code. */ | |
63 | %x SC_STRING SC_CHARACTER | |
64 | /* Whether in a rule or symbol action. Specifies the translation | |
65 | of $ and @. */ | |
66 | %x SC_RULE_ACTION SC_SYMBOL_ACTION | |
67 | ||
68 | ||
69 | /* POSIX says that a tag must be both an id and a C union member, but | |
70 | historically almost any character is allowed in a tag. We disallow | |
71 | NUL and newline, as this simplifies our implementation. */ | |
72 | tag [^\0\n>]+ | |
73 | ||
74 | /* Zero or more instances of backslash-newline. Following GCC, allow | |
75 | white space between the backslash and the newline. */ | |
76 | splice (\\[ \f\t\v]*\n)* | |
77 | ||
78 | %% | |
79 | ||
80 | %{ | |
81 | /* Nesting level of the current code in braces. */ | |
82 | int braces_level = 0; | |
83 | ||
84 | /* This scanner is special: it is invoked only once, henceforth | |
85 | is expected to return only once. This initialization is | |
86 | therefore done once per action to translate. */ | |
87 | aver (sc_context == SC_SYMBOL_ACTION | |
88 | || sc_context == SC_RULE_ACTION | |
89 | || sc_context == INITIAL); | |
90 | BEGIN sc_context; | |
91 | %} | |
92 | ||
93 | /*------------------------------------------------------------. | |
94 | | Scanning a C comment. The initial `/ *' is already eaten. | | |
95 | `------------------------------------------------------------*/ | |
96 | ||
97 | <SC_COMMENT> | |
98 | { | |
99 | "*"{splice}"/" STRING_GROW; BEGIN sc_context; | |
100 | } | |
101 | ||
102 | ||
103 | /*--------------------------------------------------------------. | |
104 | | Scanning a line comment. The initial `//' is already eaten. | | |
105 | `--------------------------------------------------------------*/ | |
106 | ||
107 | <SC_LINE_COMMENT> | |
108 | { | |
109 | "\n" STRING_GROW; BEGIN sc_context; | |
110 | {splice} STRING_GROW; | |
111 | } | |
112 | ||
113 | ||
114 | /*--------------------------------------------. | |
115 | | Scanning user-code characters and strings. | | |
116 | `--------------------------------------------*/ | |
117 | ||
118 | <SC_CHARACTER,SC_STRING> | |
119 | { | |
120 | {splice}|\\{splice}. STRING_GROW; | |
121 | } | |
122 | ||
123 | <SC_CHARACTER> | |
124 | { | |
125 | "'" STRING_GROW; BEGIN sc_context; | |
126 | } | |
127 | ||
128 | <SC_STRING> | |
129 | { | |
130 | "\"" STRING_GROW; BEGIN sc_context; | |
131 | } | |
132 | ||
133 | ||
134 | <SC_RULE_ACTION,SC_SYMBOL_ACTION>{ | |
135 | "'" { | |
136 | STRING_GROW; | |
137 | BEGIN SC_CHARACTER; | |
138 | } | |
139 | "\"" { | |
140 | STRING_GROW; | |
141 | BEGIN SC_STRING; | |
142 | } | |
143 | "/"{splice}"*" { | |
144 | STRING_GROW; | |
145 | BEGIN SC_COMMENT; | |
146 | } | |
147 | "/"{splice}"/" { | |
148 | STRING_GROW; | |
149 | BEGIN SC_LINE_COMMENT; | |
150 | } | |
151 | } | |
152 | ||
153 | <SC_RULE_ACTION> | |
154 | { | |
155 | "$"("<"{tag}">")?(-?[0-9]+|"$") { | |
156 | handle_action_dollar (self->rule, yytext, *loc); | |
157 | } | |
158 | "@"(-?[0-9]+|"$") { | |
159 | handle_action_at (self->rule, yytext, *loc); | |
160 | } | |
161 | ||
162 | "$" { | |
163 | warn_at (*loc, _("stray `$'")); | |
164 | obstack_sgrow (&obstack_for_string, "$]["); | |
165 | } | |
166 | "@" { | |
167 | warn_at (*loc, _("stray `@'")); | |
168 | obstack_sgrow (&obstack_for_string, "@@"); | |
169 | } | |
170 | ||
171 | "{" STRING_GROW; ++braces_level; | |
172 | "}" { | |
173 | bool outer_brace = --braces_level < 0; | |
174 | ||
175 | /* As an undocumented Bison extension, append `;' before the last | |
176 | brace in braced code, so that the user code can omit trailing | |
177 | `;'. But do not append `;' if emulating Yacc, since Yacc does | |
178 | not append one. | |
179 | ||
180 | FIXME: Bison should warn if a semicolon seems to be necessary | |
181 | here, and should omit the semicolon if it seems unnecessary | |
182 | (e.g., after ';', '{', or '}', each followed by comments or | |
183 | white space). Such a warning shouldn't depend on --yacc; it | |
184 | should depend on a new --pedantic option, which would cause | |
185 | Bison to warn if it detects an extension to POSIX. --pedantic | |
186 | should also diagnose other Bison extensions like %yacc. | |
187 | Perhaps there should also be a GCC-style --pedantic-errors | |
188 | option, so that such warnings are diagnosed as errors. */ | |
189 | if (outer_brace && ! yacc_flag) | |
190 | obstack_1grow (&obstack_for_string, ';'); | |
191 | ||
192 | STRING_GROW; | |
193 | } | |
194 | } | |
195 | ||
196 | <SC_SYMBOL_ACTION> | |
197 | { | |
198 | "$$" { | |
199 | obstack_sgrow (&obstack_for_string, "]b4_dollar_dollar["); | |
200 | self->is_value_used = true; | |
201 | } | |
202 | "@$" { | |
203 | obstack_sgrow (&obstack_for_string, "]b4_at_dollar["); | |
204 | locations_flag = true; | |
205 | } | |
206 | } | |
207 | ||
208 | ||
209 | /*-----------------------------------------. | |
210 | | Escape M4 quoting characters in C code. | | |
211 | `-----------------------------------------*/ | |
212 | ||
213 | <*> | |
214 | { | |
215 | \$ obstack_sgrow (&obstack_for_string, "$]["); | |
216 | \@ obstack_sgrow (&obstack_for_string, "@@"); | |
217 | \[ obstack_sgrow (&obstack_for_string, "@{"); | |
218 | \] obstack_sgrow (&obstack_for_string, "@}"); | |
219 | } | |
220 | ||
221 | /*-----------------------------------------------------. | |
222 | | By default, grow the string obstack with the input. | | |
223 | `-----------------------------------------------------*/ | |
224 | ||
225 | <*>.|\n STRING_GROW; | |
226 | ||
227 | /* End of processing. */ | |
228 | <*><<EOF>> { | |
229 | STRING_FINISH; | |
230 | return last_string; | |
231 | } | |
232 | ||
233 | %% | |
234 | ||
235 | /* Keeps track of the maximum number of semantic values to the left of | |
236 | a handle (those referenced by $0, $-1, etc.) are required by the | |
237 | semantic actions of this grammar. */ | |
238 | int max_left_semantic_context = 0; | |
239 | ||
240 | ||
241 | /*------------------------------------------------------------------. | |
242 | | TEXT is pointing to a wannabee semantic value (i.e., a `$'). | | |
243 | | | | |
244 | | Possible inputs: $[<TYPENAME>]($|integer) | | |
245 | | | | |
246 | | Output to OBSTACK_FOR_STRING a reference to this semantic value. | | |
247 | `------------------------------------------------------------------*/ | |
248 | ||
249 | static void | |
250 | handle_action_dollar (symbol_list *rule, char *text, location dollar_loc) | |
251 | { | |
252 | char const *type_name = NULL; | |
253 | char *cp = text + 1; | |
254 | symbol_list *effective_rule; | |
255 | int effective_rule_length; | |
256 | ||
257 | if (rule->midrule_parent_rule) | |
258 | { | |
259 | effective_rule = rule->midrule_parent_rule; | |
260 | effective_rule_length = rule->midrule_parent_rhs_index - 1; | |
261 | } | |
262 | else | |
263 | { | |
264 | effective_rule = rule; | |
265 | effective_rule_length = symbol_list_length (rule->next); | |
266 | } | |
267 | ||
268 | /* Get the type name if explicit. */ | |
269 | if (*cp == '<') | |
270 | { | |
271 | type_name = ++cp; | |
272 | while (*cp != '>') | |
273 | ++cp; | |
274 | *cp = '\0'; | |
275 | ++cp; | |
276 | if (untyped_var_seen) | |
277 | complain_at (dollar_loc, _("explicit type given in untyped grammar")); | |
278 | tag_seen = true; | |
279 | } | |
280 | ||
281 | if (*cp == '$') | |
282 | { | |
283 | if (!type_name) | |
284 | type_name = symbol_list_n_type_name_get (rule, dollar_loc, 0); | |
285 | ||
286 | if (!type_name) | |
287 | { | |
288 | if (union_seen | tag_seen) | |
289 | { | |
290 | if (rule->midrule_parent_rule) | |
291 | complain_at (dollar_loc, | |
292 | _("$$ for the midrule at $%d of `%s'" | |
293 | " has no declared type"), | |
294 | rule->midrule_parent_rhs_index, | |
295 | effective_rule->content.sym->tag); | |
296 | else | |
297 | complain_at (dollar_loc, _("$$ of `%s' has no declared type"), | |
298 | rule->content.sym->tag); | |
299 | } | |
300 | else | |
301 | untyped_var_seen = true; | |
302 | type_name = ""; | |
303 | } | |
304 | ||
305 | obstack_fgrow1 (&obstack_for_string, | |
306 | "]b4_lhs_value([%s])[", type_name); | |
307 | rule->action_props.is_value_used = true; | |
308 | } | |
309 | else | |
310 | { | |
311 | long int num = strtol (cp, NULL, 10); | |
312 | ||
313 | if (1 - INT_MAX + effective_rule_length <= num | |
314 | && num <= effective_rule_length) | |
315 | { | |
316 | int n = num; | |
317 | if (max_left_semantic_context < 1 - n) | |
318 | max_left_semantic_context = 1 - n; | |
319 | if (!type_name && 0 < n) | |
320 | type_name = | |
321 | symbol_list_n_type_name_get (effective_rule, dollar_loc, n); | |
322 | if (!type_name) | |
323 | { | |
324 | if (union_seen | tag_seen) | |
325 | complain_at (dollar_loc, _("$%d of `%s' has no declared type"), | |
326 | n, effective_rule->content.sym->tag); | |
327 | else | |
328 | untyped_var_seen = true; | |
329 | type_name = ""; | |
330 | } | |
331 | ||
332 | obstack_fgrow3 (&obstack_for_string, | |
333 | "]b4_rhs_value(%d, %d, [%s])[", | |
334 | effective_rule_length, n, type_name); | |
335 | if (n > 0) | |
336 | symbol_list_n_get (effective_rule, n)->action_props.is_value_used = | |
337 | true; | |
338 | } | |
339 | else | |
340 | complain_at (dollar_loc, _("integer out of range: %s"), quote (text)); | |
341 | } | |
342 | } | |
343 | ||
344 | ||
345 | /*------------------------------------------------------. | |
346 | | TEXT is a location token (i.e., a `@...'). Output to | | |
347 | | OBSTACK_FOR_STRING a reference to this location. | | |
348 | `------------------------------------------------------*/ | |
349 | ||
350 | static void | |
351 | handle_action_at (symbol_list *rule, char *text, location at_loc) | |
352 | { | |
353 | char *cp = text + 1; | |
354 | int effective_rule_length = | |
355 | (rule->midrule_parent_rule | |
356 | ? rule->midrule_parent_rhs_index - 1 | |
357 | : symbol_list_length (rule->next)); | |
358 | ||
359 | locations_flag = true; | |
360 | ||
361 | if (*cp == '$') | |
362 | obstack_sgrow (&obstack_for_string, "]b4_lhs_location["); | |
363 | else | |
364 | { | |
365 | long int num = strtol (cp, NULL, 10); | |
366 | ||
367 | if (1 - INT_MAX + effective_rule_length <= num | |
368 | && num <= effective_rule_length) | |
369 | { | |
370 | int n = num; | |
371 | obstack_fgrow2 (&obstack_for_string, "]b4_rhs_location(%d, %d)[", | |
372 | effective_rule_length, n); | |
373 | } | |
374 | else | |
375 | complain_at (at_loc, _("integer out of range: %s"), quote (text)); | |
376 | } | |
377 | } | |
378 | ||
379 | ||
380 | /*-------------------------. | |
381 | | Initialize the scanner. | | |
382 | `-------------------------*/ | |
383 | ||
384 | /* Translate the dollars and ats in \a self, in the context \a sc_context | |
385 | (SC_RULE_ACTION, SC_SYMBOL_ACTION, INITIAL). */ | |
386 | ||
387 | static char const * | |
388 | translate_action (code_props *self, int sc_context) | |
389 | { | |
390 | char *res; | |
391 | static bool initialized = false; | |
392 | if (!initialized) | |
393 | { | |
394 | obstack_init (&obstack_for_string); | |
395 | yy_flex_debug = 0; | |
396 | initialized = true; | |
397 | } | |
398 | ||
399 | loc->start = loc->end = self->location.start; | |
400 | yy_switch_to_buffer (yy_scan_string (self->code)); | |
401 | res = code_lex (self, sc_context); | |
402 | yy_delete_buffer (YY_CURRENT_BUFFER); | |
403 | ||
404 | return res; | |
405 | } | |
406 | ||
407 | /*------------------------------------------------------------------------. | |
408 | | Implementation of the public interface as documented in "scan-code.h". | | |
409 | `------------------------------------------------------------------------*/ | |
410 | ||
411 | void | |
412 | code_props_none_init (code_props *self) | |
413 | { | |
414 | *self = code_props_none; | |
415 | } | |
416 | ||
417 | code_props const code_props_none = CODE_PROPS_NONE_INIT; | |
418 | ||
419 | void | |
420 | code_props_plain_init (code_props *self, char const *code, location code_loc) | |
421 | { | |
422 | self->kind = CODE_PROPS_PLAIN; | |
423 | self->code = code; | |
424 | self->location = code_loc; | |
425 | self->is_value_used = false; | |
426 | self->rule = NULL; | |
427 | } | |
428 | ||
429 | void | |
430 | code_props_symbol_action_init (code_props *self, char const *code, | |
431 | location code_loc) | |
432 | { | |
433 | self->kind = CODE_PROPS_SYMBOL_ACTION; | |
434 | self->code = code; | |
435 | self->location = code_loc; | |
436 | self->is_value_used = false; | |
437 | self->rule = NULL; | |
438 | } | |
439 | ||
440 | void | |
441 | code_props_rule_action_init (code_props *self, char const *code, | |
442 | location code_loc, symbol_list *rule) | |
443 | { | |
444 | self->kind = CODE_PROPS_RULE_ACTION; | |
445 | self->code = code; | |
446 | self->location = code_loc; | |
447 | self->is_value_used = false; | |
448 | self->rule = rule; | |
449 | } | |
450 | ||
451 | void | |
452 | code_props_translate_code (code_props *self) | |
453 | { | |
454 | switch (self->kind) | |
455 | { | |
456 | case CODE_PROPS_NONE: | |
457 | break; | |
458 | case CODE_PROPS_PLAIN: | |
459 | self->code = translate_action (self, INITIAL); | |
460 | break; | |
461 | case CODE_PROPS_SYMBOL_ACTION: | |
462 | self->code = translate_action (self, SC_SYMBOL_ACTION); | |
463 | break; | |
464 | case CODE_PROPS_RULE_ACTION: | |
465 | self->code = translate_action (self, SC_RULE_ACTION); | |
466 | break; | |
467 | } | |
468 | } | |
469 | ||
470 | void | |
471 | code_scanner_last_string_free (void) | |
472 | { | |
473 | STRING_FREE; | |
474 | } | |
475 | ||
476 | void | |
477 | code_scanner_free (void) | |
478 | { | |
479 | obstack_free (&obstack_for_string, 0); | |
480 | /* Reclaim Flex's buffers. */ | |
481 | yylex_destroy (); | |
482 | } |