1 | /* Type Analyzer for GNU C++. |
---|
2 | Copyright (C) 1987, 89, 92, 93, 94, 1995 Free Software Foundation, Inc. |
---|
3 | Hacked... nay, bludgeoned... by Mark Eichin (eichin@cygnus.com) |
---|
4 | |
---|
5 | This file is part of GNU CC. |
---|
6 | |
---|
7 | GNU CC 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 2, or (at your option) |
---|
10 | any later version. |
---|
11 | |
---|
12 | GNU CC 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 GNU CC; see the file COPYING. If not, write to |
---|
19 | the Free Software Foundation, 59 Temple Place - Suite 330, |
---|
20 | Boston, MA 02111-1307, USA. */ |
---|
21 | |
---|
22 | |
---|
23 | /* This file is the type analyzer for GNU C++. To debug it, define SPEW_DEBUG |
---|
24 | when compiling parse.c and spew.c. */ |
---|
25 | |
---|
26 | #include "config.h" |
---|
27 | #include <stdio.h> |
---|
28 | #include "input.h" |
---|
29 | #include "tree.h" |
---|
30 | #include "lex.h" |
---|
31 | #include "parse.h" |
---|
32 | #include "cp-tree.h" |
---|
33 | #include "flags.h" |
---|
34 | #include "obstack.h" |
---|
35 | |
---|
36 | /* This takes a token stream that hasn't decided much about types and |
---|
37 | tries to figure out as much as it can, with excessive lookahead and |
---|
38 | backtracking. */ |
---|
39 | |
---|
40 | /* fifo of tokens recognized and available to parser. */ |
---|
41 | struct token { |
---|
42 | /* The values for YYCHAR will fit in a short. */ |
---|
43 | short yychar; |
---|
44 | short end_of_file; |
---|
45 | YYSTYPE yylval; |
---|
46 | }; |
---|
47 | |
---|
48 | static int do_aggr (); |
---|
49 | |
---|
50 | /* From lex.c: */ |
---|
51 | /* the declaration found for the last IDENTIFIER token read in. |
---|
52 | yylex must look this up to detect typedefs, which get token type TYPENAME, |
---|
53 | so it is left around in case the identifier is not a typedef but is |
---|
54 | used in a context which makes it a reference to a variable. */ |
---|
55 | extern tree lastiddecl; /* let our brains leak out here too */ |
---|
56 | extern int yychar; /* the lookahead symbol */ |
---|
57 | extern YYSTYPE yylval; /* the semantic value of the */ |
---|
58 | /* lookahead symbol */ |
---|
59 | extern int end_of_file; |
---|
60 | |
---|
61 | struct obstack token_obstack; |
---|
62 | int first_token; |
---|
63 | |
---|
64 | #ifdef SPEW_DEBUG |
---|
65 | int spew_debug = 0; |
---|
66 | static unsigned int yylex_ctr = 0; |
---|
67 | static int debug_yychar (); |
---|
68 | #endif |
---|
69 | |
---|
70 | /* Initialize token_obstack. Called once, from init_lex. */ |
---|
71 | void |
---|
72 | init_spew () |
---|
73 | { |
---|
74 | gcc_obstack_init(&token_obstack); |
---|
75 | } |
---|
76 | |
---|
77 | #ifdef SPEW_DEBUG |
---|
78 | /* Use functions for debugging... */ |
---|
79 | |
---|
80 | /* Return the number of tokens available on the fifo. */ |
---|
81 | static int |
---|
82 | num_tokens () |
---|
83 | { |
---|
84 | return (obstack_object_size(&token_obstack)/sizeof(struct token)) |
---|
85 | - first_token; |
---|
86 | } |
---|
87 | |
---|
88 | /* Fetch the token N down the line from the head of the fifo. */ |
---|
89 | static struct token* |
---|
90 | nth_token (n) |
---|
91 | int n; |
---|
92 | { |
---|
93 | /* could just have this do slurp_ implicitly, but this way is easier |
---|
94 | * to debug... */ |
---|
95 | my_friendly_assert (n < num_tokens(), 298); |
---|
96 | return ((struct token*)obstack_base(&token_obstack))+n+first_token; |
---|
97 | } |
---|
98 | |
---|
99 | /* Add a token to the token fifo. */ |
---|
100 | static void |
---|
101 | add_token (t) |
---|
102 | struct token* t; |
---|
103 | { |
---|
104 | obstack_grow(&token_obstack,t,sizeof (struct token)); |
---|
105 | } |
---|
106 | |
---|
107 | /* Consume the next token out of the fifo. */ |
---|
108 | static void |
---|
109 | consume_token() |
---|
110 | { |
---|
111 | if (num_tokens() == 1) |
---|
112 | { |
---|
113 | obstack_free(&token_obstack, obstack_base (&token_obstack)); |
---|
114 | first_token = 0; |
---|
115 | } |
---|
116 | else |
---|
117 | first_token++; |
---|
118 | } |
---|
119 | |
---|
120 | #else |
---|
121 | /* ...otherwise use macros. */ |
---|
122 | |
---|
123 | #define num_tokens() \ |
---|
124 | ((obstack_object_size(&token_obstack)/sizeof(struct token)) - first_token) |
---|
125 | |
---|
126 | #define nth_token(N) \ |
---|
127 | (((struct token*)obstack_base(&token_obstack))+(N)+first_token) |
---|
128 | |
---|
129 | #define add_token(T) obstack_grow(&token_obstack, (T), sizeof (struct token)) |
---|
130 | |
---|
131 | #define consume_token() \ |
---|
132 | (num_tokens() == 1 \ |
---|
133 | ? (obstack_free (&token_obstack, obstack_base (&token_obstack)), \ |
---|
134 | (first_token = 0)) \ |
---|
135 | : first_token++) |
---|
136 | #endif |
---|
137 | |
---|
138 | /* Pull in enough tokens from real_yylex that the queue is N long beyond |
---|
139 | the current token. */ |
---|
140 | |
---|
141 | static void |
---|
142 | scan_tokens (n) |
---|
143 | int n; |
---|
144 | { |
---|
145 | int i; |
---|
146 | struct token *tmp; |
---|
147 | |
---|
148 | /* We cannot read past certain tokens, so make sure we don't. */ |
---|
149 | i = num_tokens (); |
---|
150 | if (i > n) |
---|
151 | return; |
---|
152 | while (i-- > 0) |
---|
153 | { |
---|
154 | tmp = nth_token (i); |
---|
155 | /* Never read past these characters: they might separate |
---|
156 | the current input stream from one we save away later. */ |
---|
157 | if (tmp->yychar == '{' || tmp->yychar == ':' || tmp->yychar == ';') |
---|
158 | goto pad_tokens; |
---|
159 | } |
---|
160 | |
---|
161 | while (num_tokens() <= n) |
---|
162 | { |
---|
163 | obstack_blank(&token_obstack,sizeof (struct token)); |
---|
164 | tmp = ((struct token *)obstack_next_free (&token_obstack))-1; |
---|
165 | tmp->yychar = real_yylex(); |
---|
166 | tmp->end_of_file = end_of_file; |
---|
167 | tmp->yylval = yylval; |
---|
168 | end_of_file = 0; |
---|
169 | if (tmp->yychar == '{' |
---|
170 | || tmp->yychar == ':' |
---|
171 | || tmp->yychar == ';') |
---|
172 | { |
---|
173 | pad_tokens: |
---|
174 | while (num_tokens () <= n) |
---|
175 | { |
---|
176 | obstack_blank(&token_obstack,sizeof (struct token)); |
---|
177 | tmp = ((struct token *)obstack_next_free (&token_obstack))-1; |
---|
178 | tmp->yychar = EMPTY; |
---|
179 | tmp->end_of_file = 0; |
---|
180 | } |
---|
181 | } |
---|
182 | } |
---|
183 | } |
---|
184 | |
---|
185 | /* Create room for N tokens at the front of the fifo. This is used |
---|
186 | to insert new tokens into the stream ahead of the current token. */ |
---|
187 | |
---|
188 | static void |
---|
189 | shift_tokens (n) |
---|
190 | int n; |
---|
191 | { |
---|
192 | if (first_token >= n) |
---|
193 | first_token -= n; |
---|
194 | else |
---|
195 | { |
---|
196 | int old_token_count = num_tokens (); |
---|
197 | char *tmp; |
---|
198 | |
---|
199 | obstack_blank (&token_obstack, (n-first_token) * sizeof (struct token)); |
---|
200 | if (old_token_count) |
---|
201 | { |
---|
202 | tmp = (char *)alloca ((num_tokens () + (n-first_token)) |
---|
203 | * sizeof (struct token)); |
---|
204 | /* This move does not rely on the system being able to handle |
---|
205 | overlapping moves. */ |
---|
206 | bcopy ((char *) nth_token (0), tmp, |
---|
207 | old_token_count * sizeof (struct token)); |
---|
208 | bcopy (tmp, (char *) nth_token (n), |
---|
209 | old_token_count * sizeof (struct token)); |
---|
210 | } |
---|
211 | first_token = 0; |
---|
212 | } |
---|
213 | } |
---|
214 | |
---|
215 | static int |
---|
216 | probe_obstack (h, obj, nlevels) |
---|
217 | struct obstack *h; |
---|
218 | tree obj; |
---|
219 | unsigned int nlevels; |
---|
220 | { |
---|
221 | register struct _obstack_chunk* lp; /* below addr of any objects in this chunk */ |
---|
222 | register struct _obstack_chunk* plp; /* point to previous chunk if any */ |
---|
223 | |
---|
224 | lp = (h)->chunk; |
---|
225 | /* We use >= rather than > since the object cannot be exactly at |
---|
226 | the beginning of the chunk but might be an empty object exactly |
---|
227 | at the end of an adjacent chunk. */ |
---|
228 | for (; nlevels != 0 && lp != 0 && ((tree)lp >= obj || (tree)lp->limit < obj); |
---|
229 | nlevels -= 1) |
---|
230 | { |
---|
231 | plp = lp->prev; |
---|
232 | lp = plp; |
---|
233 | } |
---|
234 | return nlevels != 0 && lp != 0; |
---|
235 | } |
---|
236 | |
---|
237 | /* from lex.c: */ |
---|
238 | /* Value is 1 (or 2) if we should try to make the next identifier look like |
---|
239 | a typename (when it may be a local variable or a class variable). |
---|
240 | Value is 0 if we treat this name in a default fashion. */ |
---|
241 | extern int looking_for_typename; |
---|
242 | int looking_for_template; |
---|
243 | |
---|
244 | extern struct obstack *current_obstack, *saveable_obstack; |
---|
245 | tree got_scope; |
---|
246 | tree got_object; |
---|
247 | |
---|
248 | int |
---|
249 | peekyylex() |
---|
250 | { |
---|
251 | scan_tokens (0); |
---|
252 | return nth_token (0)->yychar; |
---|
253 | } |
---|
254 | |
---|
255 | int |
---|
256 | yylex() |
---|
257 | { |
---|
258 | struct token tmp_token; |
---|
259 | tree trrr; |
---|
260 | |
---|
261 | retry: |
---|
262 | #ifdef SPEW_DEBUG |
---|
263 | if (spew_debug) |
---|
264 | { |
---|
265 | yylex_ctr ++; |
---|
266 | fprintf(stderr, "\t\t## %d ##",yylex_ctr); |
---|
267 | } |
---|
268 | #endif |
---|
269 | |
---|
270 | /* if we've got tokens, send them */ |
---|
271 | if (num_tokens()) |
---|
272 | { |
---|
273 | tmp_token= *nth_token(0); |
---|
274 | |
---|
275 | /* TMP_TOKEN.YYLVAL.TTYPE may have been allocated on the wrong obstack. |
---|
276 | If we don't find it in CURRENT_OBSTACK's current or immediately |
---|
277 | previous chunk, assume it was and copy it to the current obstack. */ |
---|
278 | if ((tmp_token.yychar == CONSTANT |
---|
279 | || tmp_token.yychar == STRING) |
---|
280 | && ! TREE_PERMANENT (tmp_token.yylval.ttype) |
---|
281 | && ! probe_obstack (current_obstack, tmp_token.yylval.ttype, 2) |
---|
282 | && ! probe_obstack (saveable_obstack, tmp_token.yylval.ttype, 2)) |
---|
283 | tmp_token.yylval.ttype = copy_node (tmp_token.yylval.ttype); |
---|
284 | } |
---|
285 | else |
---|
286 | { |
---|
287 | /* if not, grab the next one and think about it */ |
---|
288 | tmp_token.yychar = real_yylex (); |
---|
289 | tmp_token.yylval = yylval; |
---|
290 | tmp_token.end_of_file = end_of_file; |
---|
291 | add_token(&tmp_token); |
---|
292 | } |
---|
293 | |
---|
294 | /* many tokens just need to be returned. At first glance, all we |
---|
295 | * have to do is send them back up, but some of them are needed to |
---|
296 | * figure out local context. */ |
---|
297 | switch(tmp_token.yychar) |
---|
298 | { |
---|
299 | case EMPTY: |
---|
300 | /* This is a lexical no-op. */ |
---|
301 | consume_token (); |
---|
302 | #ifdef SPEW_DEBUG |
---|
303 | if (spew_debug) |
---|
304 | debug_yychar (tmp_token.yychar); |
---|
305 | #endif |
---|
306 | goto retry; |
---|
307 | |
---|
308 | case IDENTIFIER: |
---|
309 | scan_tokens (1); |
---|
310 | if (nth_token (1)->yychar == SCOPE) |
---|
311 | /* Don't interfere with the setting from an 'aggr' prefix. */ |
---|
312 | looking_for_typename++; |
---|
313 | else if (nth_token (1)->yychar == '<') |
---|
314 | looking_for_template = 1; |
---|
315 | |
---|
316 | trrr = lookup_name (tmp_token.yylval.ttype, -2); |
---|
317 | |
---|
318 | if (trrr) |
---|
319 | { |
---|
320 | tmp_token.yychar = identifier_type (trrr); |
---|
321 | switch (tmp_token.yychar) |
---|
322 | { |
---|
323 | case TYPENAME: |
---|
324 | lastiddecl = identifier_typedecl_value (tmp_token.yylval.ttype); |
---|
325 | if (lastiddecl != trrr) |
---|
326 | { |
---|
327 | lastiddecl = trrr; |
---|
328 | if (got_scope || got_object) |
---|
329 | tmp_token.yylval.ttype = DECL_NESTED_TYPENAME (trrr); |
---|
330 | } |
---|
331 | break; |
---|
332 | case IDENTIFIER: |
---|
333 | lastiddecl = trrr; |
---|
334 | break; |
---|
335 | case PTYPENAME: |
---|
336 | lastiddecl = NULL_TREE; |
---|
337 | break; |
---|
338 | case NSNAME: |
---|
339 | lastiddecl = trrr; |
---|
340 | if (got_scope || got_object) |
---|
341 | tmp_token.yylval.ttype = trrr; |
---|
342 | break; |
---|
343 | default: |
---|
344 | my_friendly_abort (101); |
---|
345 | } |
---|
346 | } |
---|
347 | else |
---|
348 | lastiddecl = trrr; |
---|
349 | got_scope = NULL_TREE; |
---|
350 | /* and fall through to... */ |
---|
351 | case IDENTIFIER_DEFN: |
---|
352 | case TYPENAME: |
---|
353 | case TYPENAME_DEFN: |
---|
354 | case PTYPENAME: |
---|
355 | case PTYPENAME_DEFN: |
---|
356 | consume_token (); |
---|
357 | if (looking_for_typename > 0) |
---|
358 | looking_for_typename--; |
---|
359 | looking_for_template = 0; |
---|
360 | break; |
---|
361 | |
---|
362 | case SCSPEC: |
---|
363 | /* do_aggr needs to check if the previous token was RID_FRIEND, |
---|
364 | so just increment first_token instead of calling consume_token. */ |
---|
365 | first_token++; |
---|
366 | break; |
---|
367 | case TYPESPEC: |
---|
368 | consume_token (); |
---|
369 | break; |
---|
370 | |
---|
371 | case AGGR: |
---|
372 | *nth_token(0) = tmp_token; |
---|
373 | do_aggr (); |
---|
374 | /* fall through to output... */ |
---|
375 | case ENUM: |
---|
376 | /* Set this again, in case we are rescanning. */ |
---|
377 | looking_for_typename = 1; |
---|
378 | /* fall through... */ |
---|
379 | default: |
---|
380 | consume_token(); |
---|
381 | } |
---|
382 | |
---|
383 | yylval = tmp_token.yylval; |
---|
384 | yychar = tmp_token.yychar; |
---|
385 | end_of_file = tmp_token.end_of_file; |
---|
386 | #ifdef SPEW_DEBUG |
---|
387 | if (spew_debug) |
---|
388 | debug_yychar(yychar); |
---|
389 | #endif |
---|
390 | return yychar; |
---|
391 | } |
---|
392 | |
---|
393 | /* token[0] == AGGR (struct/union/enum) |
---|
394 | * Thus, token[1] is either a TYPENAME or a TYPENAME_DEFN. |
---|
395 | * If token[2] == '{' or ':' then it's TYPENAME_DEFN. |
---|
396 | * It's also a definition if it's a forward declaration (as in 'struct Foo;') |
---|
397 | * which we can tell lf token[2] == ';' *and* token[-1] != FRIEND. |
---|
398 | */ |
---|
399 | static int |
---|
400 | do_aggr () |
---|
401 | { |
---|
402 | int yc1, yc2; |
---|
403 | |
---|
404 | scan_tokens (2); |
---|
405 | yc1 = nth_token (1)->yychar; |
---|
406 | if (yc1 != TYPENAME && yc1 != IDENTIFIER && yc1 != PTYPENAME) |
---|
407 | return 0; |
---|
408 | yc2 = nth_token (2)->yychar; |
---|
409 | if (yc2 == ';') |
---|
410 | { |
---|
411 | /* It's a forward declaration iff we were not preceded by 'friend'. */ |
---|
412 | if (first_token > 0 && nth_token (-1)->yychar == SCSPEC |
---|
413 | && nth_token (-1)->yylval.ttype == ridpointers[(int) RID_FRIEND]) |
---|
414 | return 0; |
---|
415 | } |
---|
416 | else if (yc2 != '{' && yc2 != ':') |
---|
417 | return 0; |
---|
418 | |
---|
419 | switch (yc1) |
---|
420 | { |
---|
421 | case TYPENAME: |
---|
422 | nth_token (1)->yychar = TYPENAME_DEFN; |
---|
423 | break; |
---|
424 | case PTYPENAME: |
---|
425 | nth_token (1)->yychar = PTYPENAME_DEFN; |
---|
426 | break; |
---|
427 | case IDENTIFIER: |
---|
428 | nth_token (1)->yychar = IDENTIFIER_DEFN; |
---|
429 | break; |
---|
430 | default: |
---|
431 | my_friendly_abort (102); |
---|
432 | } |
---|
433 | return 0; |
---|
434 | } |
---|
435 | |
---|
436 | #ifdef SPEW_DEBUG |
---|
437 | /* debug_yychar takes a yychar (token number) value and prints its name. */ |
---|
438 | static int |
---|
439 | debug_yychar (yy) |
---|
440 | int yy; |
---|
441 | { |
---|
442 | /* In parse.y: */ |
---|
443 | extern char *debug_yytranslate (); |
---|
444 | |
---|
445 | int i; |
---|
446 | |
---|
447 | if(yy<256) { |
---|
448 | fprintf (stderr, "<%d: %c >\n", yy, yy); |
---|
449 | return 0; |
---|
450 | } |
---|
451 | fprintf (stderr, "<%d:%s>\n", yy, debug_yytranslate (yy)); |
---|
452 | return 1; |
---|
453 | } |
---|
454 | |
---|
455 | #endif |
---|