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3d6b6a90 JG |
1 | /* Parse expressions for GDB. |
2 | Copyright (C) 1986, 1989, 1990, 1991 Free Software Foundation, Inc. | |
3 | Modified from expread.y by the Department of Computer Science at the | |
4 | State University of New York at Buffalo, 1991. | |
5 | ||
6 | This file is part of GDB. | |
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 2 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, write to the Free Software | |
20 | Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ | |
21 | ||
22 | /* Parse an expression from text in a string, | |
23 | and return the result as a struct expression pointer. | |
24 | That structure contains arithmetic operations in reverse polish, | |
25 | with constants represented by operations that are followed by special data. | |
26 | See expression.h for the details of the format. | |
27 | What is important here is that it can be built up sequentially | |
28 | during the process of parsing; the lower levels of the tree always | |
29 | come first in the result. */ | |
30 | ||
31 | #include <stdio.h> | |
32 | #include "defs.h" | |
3d6b6a90 JG |
33 | #include "symtab.h" |
34 | #include "frame.h" | |
35 | #include "expression.h" | |
36 | #include "value.h" | |
37 | #include "command.h" | |
38 | #include "language.h" | |
39 | #include "parser-defs.h" | |
40 | ||
41 | /* Assign machine-independent names to certain registers | |
42 | (unless overridden by the REGISTER_NAMES table) */ | |
43 | ||
44 | struct std_regs std_regs[] = { | |
45 | #ifdef PC_REGNUM | |
46 | { "pc", PC_REGNUM }, | |
47 | #endif | |
48 | #ifdef FP_REGNUM | |
49 | { "fp", FP_REGNUM }, | |
50 | #endif | |
51 | #ifdef SP_REGNUM | |
52 | { "sp", SP_REGNUM }, | |
53 | #endif | |
54 | #ifdef PS_REGNUM | |
55 | { "ps", PS_REGNUM }, | |
56 | #endif | |
57 | }; | |
58 | ||
59 | unsigned num_std_regs = (sizeof std_regs / sizeof std_regs[0]); | |
60 | ||
61 | ||
62 | /* Begin counting arguments for a function call, | |
63 | saving the data about any containing call. */ | |
64 | ||
65 | void | |
66 | start_arglist () | |
67 | { | |
68 | register struct funcall *new = (struct funcall *) xmalloc (sizeof (struct funcall)); | |
69 | ||
70 | new->next = funcall_chain; | |
71 | new->arglist_len = arglist_len; | |
72 | arglist_len = 0; | |
73 | funcall_chain = new; | |
74 | } | |
75 | ||
76 | /* Return the number of arguments in a function call just terminated, | |
77 | and restore the data for the containing function call. */ | |
78 | ||
79 | int | |
80 | end_arglist () | |
81 | { | |
82 | register int val = arglist_len; | |
83 | register struct funcall *call = funcall_chain; | |
84 | funcall_chain = call->next; | |
85 | arglist_len = call->arglist_len; | |
86 | free (call); | |
87 | return val; | |
88 | } | |
89 | ||
90 | /* Free everything in the funcall chain. | |
91 | Used when there is an error inside parsing. */ | |
92 | ||
93 | void | |
94 | free_funcalls () | |
95 | { | |
96 | register struct funcall *call, *next; | |
97 | ||
98 | for (call = funcall_chain; call; call = next) | |
99 | { | |
100 | next = call->next; | |
101 | free (call); | |
102 | } | |
103 | } | |
104 | \f | |
105 | /* This page contains the functions for adding data to the struct expression | |
106 | being constructed. */ | |
107 | ||
108 | /* Add one element to the end of the expression. */ | |
109 | ||
110 | /* To avoid a bug in the Sun 4 compiler, we pass things that can fit into | |
111 | a register through here */ | |
112 | ||
113 | void | |
114 | write_exp_elt (expelt) | |
115 | union exp_element expelt; | |
116 | { | |
117 | if (expout_ptr >= expout_size) | |
118 | { | |
119 | expout_size *= 2; | |
120 | expout = (struct expression *) xrealloc (expout, | |
121 | sizeof (struct expression) | |
122 | + expout_size * sizeof (union exp_element)); | |
123 | } | |
124 | expout->elts[expout_ptr++] = expelt; | |
125 | } | |
126 | ||
127 | void | |
128 | write_exp_elt_opcode (expelt) | |
129 | enum exp_opcode expelt; | |
130 | { | |
131 | union exp_element tmp; | |
132 | ||
133 | tmp.opcode = expelt; | |
134 | ||
135 | write_exp_elt (tmp); | |
136 | } | |
137 | ||
138 | void | |
139 | write_exp_elt_sym (expelt) | |
140 | struct symbol *expelt; | |
141 | { | |
142 | union exp_element tmp; | |
143 | ||
144 | tmp.symbol = expelt; | |
145 | ||
146 | write_exp_elt (tmp); | |
147 | } | |
148 | ||
149 | void | |
150 | write_exp_elt_longcst (expelt) | |
151 | LONGEST expelt; | |
152 | { | |
153 | union exp_element tmp; | |
154 | ||
155 | tmp.longconst = expelt; | |
156 | ||
157 | write_exp_elt (tmp); | |
158 | } | |
159 | ||
160 | void | |
161 | write_exp_elt_dblcst (expelt) | |
162 | double expelt; | |
163 | { | |
164 | union exp_element tmp; | |
165 | ||
166 | tmp.doubleconst = expelt; | |
167 | ||
168 | write_exp_elt (tmp); | |
169 | } | |
170 | ||
171 | void | |
172 | write_exp_elt_type (expelt) | |
173 | struct type *expelt; | |
174 | { | |
175 | union exp_element tmp; | |
176 | ||
177 | tmp.type = expelt; | |
178 | ||
179 | write_exp_elt (tmp); | |
180 | } | |
181 | ||
182 | void | |
183 | write_exp_elt_intern (expelt) | |
184 | struct internalvar *expelt; | |
185 | { | |
186 | union exp_element tmp; | |
187 | ||
188 | tmp.internalvar = expelt; | |
189 | ||
190 | write_exp_elt (tmp); | |
191 | } | |
192 | ||
193 | /* Add a string constant to the end of the expression. | |
194 | Follow it by its length in bytes, as a separate exp_element. */ | |
195 | ||
196 | void | |
197 | write_exp_string (str) | |
198 | struct stoken str; | |
199 | { | |
200 | register int len = str.length; | |
201 | register int lenelt | |
202 | = (len + sizeof (union exp_element)) / sizeof (union exp_element); | |
203 | ||
204 | expout_ptr += lenelt; | |
205 | ||
206 | if (expout_ptr >= expout_size) | |
207 | { | |
208 | expout_size = max (expout_size * 2, expout_ptr + 10); | |
209 | expout = (struct expression *) | |
210 | xrealloc (expout, (sizeof (struct expression) | |
211 | + (expout_size * sizeof (union exp_element)))); | |
212 | } | |
213 | bcopy (str.ptr, (char *) &expout->elts[expout_ptr - lenelt], len); | |
214 | ((char *) &expout->elts[expout_ptr - lenelt])[len] = 0; | |
215 | write_exp_elt_longcst ((LONGEST) len); | |
216 | } | |
217 | \f | |
218 | /* Return a null-terminated temporary copy of the name | |
219 | of a string token. */ | |
220 | ||
221 | char * | |
222 | copy_name (token) | |
223 | struct stoken token; | |
224 | { | |
225 | bcopy (token.ptr, namecopy, token.length); | |
226 | namecopy[token.length] = 0; | |
227 | return namecopy; | |
228 | } | |
229 | \f | |
230 | /* Reverse an expression from suffix form (in which it is constructed) | |
231 | to prefix form (in which we can conveniently print or execute it). */ | |
232 | ||
233 | static void prefixify_subexp (); | |
234 | ||
235 | void | |
236 | prefixify_expression (expr) | |
237 | register struct expression *expr; | |
238 | { | |
239 | register int len = sizeof (struct expression) + | |
240 | expr->nelts * sizeof (union exp_element); | |
241 | register struct expression *temp; | |
242 | register int inpos = expr->nelts, outpos = 0; | |
243 | ||
244 | temp = (struct expression *) alloca (len); | |
245 | ||
246 | /* Copy the original expression into temp. */ | |
247 | bcopy (expr, temp, len); | |
248 | ||
249 | prefixify_subexp (temp, expr, inpos, outpos); | |
250 | } | |
251 | ||
252 | /* Return the number of exp_elements in the subexpression of EXPR | |
253 | whose last exp_element is at index ENDPOS - 1 in EXPR. */ | |
254 | ||
255 | int | |
256 | length_of_subexp (expr, endpos) | |
257 | register struct expression *expr; | |
258 | register int endpos; | |
259 | { | |
260 | register int oplen = 1; | |
261 | register int args = 0; | |
262 | register int i; | |
263 | ||
264 | if (endpos < 0) | |
265 | error ("?error in length_of_subexp"); | |
266 | ||
267 | i = (int) expr->elts[endpos - 1].opcode; | |
268 | ||
269 | switch (i) | |
270 | { | |
271 | /* C++ */ | |
272 | case OP_SCOPE: | |
273 | oplen = 4 + ((expr->elts[endpos - 2].longconst | |
274 | + sizeof (union exp_element)) | |
275 | / sizeof (union exp_element)); | |
276 | break; | |
277 | ||
278 | case OP_LONG: | |
279 | case OP_DOUBLE: | |
280 | oplen = 4; | |
281 | break; | |
282 | ||
283 | case OP_TYPE: | |
284 | case OP_BOOL: | |
285 | case OP_VAR_VALUE: | |
286 | case OP_LAST: | |
287 | case OP_REGISTER: | |
288 | case OP_INTERNALVAR: | |
289 | oplen = 3; | |
290 | break; | |
291 | ||
292 | case OP_FUNCALL: | |
293 | oplen = 3; | |
294 | args = 1 + expr->elts[endpos - 2].longconst; | |
295 | break; | |
296 | ||
297 | case UNOP_MAX: | |
298 | case UNOP_MIN: | |
299 | oplen = 3; | |
300 | args = 0; | |
301 | break; | |
302 | ||
303 | case BINOP_VAL: | |
304 | case UNOP_CAST: | |
305 | case UNOP_MEMVAL: | |
306 | oplen = 3; | |
307 | args = 1; | |
308 | break; | |
309 | ||
310 | case UNOP_ABS: | |
311 | case UNOP_CAP: | |
312 | case UNOP_CHR: | |
313 | case UNOP_FLOAT: | |
314 | case UNOP_HIGH: | |
315 | case UNOP_ODD: | |
316 | case UNOP_ORD: | |
317 | case UNOP_TRUNC: | |
318 | oplen = 1; | |
319 | args = 1; | |
320 | break; | |
321 | ||
322 | case STRUCTOP_STRUCT: | |
323 | case STRUCTOP_PTR: | |
324 | args = 1; | |
325 | case OP_M2_STRING: | |
326 | case OP_STRING: | |
327 | oplen = 3 + ((expr->elts[endpos - 2].longconst | |
328 | + sizeof (union exp_element)) | |
329 | / sizeof (union exp_element)); | |
330 | break; | |
331 | ||
332 | case TERNOP_COND: | |
333 | args = 3; | |
334 | break; | |
335 | ||
336 | /* Modula-2 */ | |
337 | case BINOP_MULTI_SUBSCRIPT: | |
338 | oplen=3; | |
339 | args = 1 + expr->elts[endpos- 2].longconst; | |
340 | break; | |
341 | ||
342 | case BINOP_ASSIGN_MODIFY: | |
343 | oplen = 3; | |
344 | args = 2; | |
345 | break; | |
346 | ||
347 | /* C++ */ | |
348 | case OP_THIS: | |
349 | oplen = 2; | |
350 | break; | |
351 | ||
352 | default: | |
353 | args = 1 + (i < (int) BINOP_END); | |
354 | } | |
355 | ||
356 | while (args > 0) | |
357 | { | |
358 | oplen += length_of_subexp (expr, endpos - oplen); | |
359 | args--; | |
360 | } | |
361 | ||
362 | return oplen; | |
363 | } | |
364 | ||
365 | /* Copy the subexpression ending just before index INEND in INEXPR | |
366 | into OUTEXPR, starting at index OUTBEG. | |
367 | In the process, convert it from suffix to prefix form. */ | |
368 | ||
369 | static void | |
370 | prefixify_subexp (inexpr, outexpr, inend, outbeg) | |
371 | register struct expression *inexpr; | |
372 | struct expression *outexpr; | |
373 | register int inend; | |
374 | int outbeg; | |
375 | { | |
376 | register int oplen = 1; | |
377 | register int args = 0; | |
378 | register int i; | |
379 | int *arglens; | |
380 | enum exp_opcode opcode; | |
381 | ||
382 | /* Compute how long the last operation is (in OPLEN), | |
383 | and also how many preceding subexpressions serve as | |
384 | arguments for it (in ARGS). */ | |
385 | ||
386 | opcode = inexpr->elts[inend - 1].opcode; | |
387 | switch (opcode) | |
388 | { | |
389 | /* C++ */ | |
390 | case OP_SCOPE: | |
391 | oplen = 4 + ((inexpr->elts[inend - 2].longconst | |
392 | + sizeof (union exp_element)) | |
393 | / sizeof (union exp_element)); | |
394 | break; | |
395 | ||
396 | case OP_LONG: | |
397 | case OP_DOUBLE: | |
398 | oplen = 4; | |
399 | break; | |
400 | ||
401 | case OP_TYPE: | |
402 | case OP_BOOL: | |
403 | case OP_VAR_VALUE: | |
404 | case OP_LAST: | |
405 | case OP_REGISTER: | |
406 | case OP_INTERNALVAR: | |
407 | oplen = 3; | |
408 | break; | |
409 | ||
410 | case OP_FUNCALL: | |
411 | oplen = 3; | |
412 | args = 1 + inexpr->elts[inend - 2].longconst; | |
413 | break; | |
414 | ||
415 | case UNOP_MIN: | |
416 | case UNOP_MAX: | |
417 | oplen = 3; | |
418 | args = 0; | |
419 | break; | |
420 | ||
421 | case UNOP_CAST: | |
422 | case UNOP_MEMVAL: | |
423 | oplen = 3; | |
424 | args = 1; | |
425 | break; | |
426 | ||
427 | case UNOP_ABS: | |
428 | case UNOP_CAP: | |
429 | case UNOP_CHR: | |
430 | case UNOP_FLOAT: | |
431 | case UNOP_HIGH: | |
432 | case UNOP_ODD: | |
433 | case UNOP_ORD: | |
434 | case UNOP_TRUNC: | |
435 | oplen=1; | |
436 | args=1; | |
437 | break; | |
438 | ||
439 | case STRUCTOP_STRUCT: | |
440 | case STRUCTOP_PTR: | |
441 | args = 1; | |
442 | case OP_M2_STRING: | |
443 | case OP_STRING: | |
444 | oplen = 3 + ((inexpr->elts[inend - 2].longconst | |
445 | + sizeof (union exp_element)) | |
446 | / sizeof (union exp_element)); | |
447 | ||
448 | break; | |
449 | ||
450 | case TERNOP_COND: | |
451 | args = 3; | |
452 | break; | |
453 | ||
454 | case BINOP_ASSIGN_MODIFY: | |
455 | oplen = 3; | |
456 | args = 2; | |
457 | break; | |
458 | ||
459 | /* Modula-2 */ | |
460 | case BINOP_MULTI_SUBSCRIPT: | |
461 | oplen=3; | |
462 | args = 1 + inexpr->elts[inend - 2].longconst; | |
463 | break; | |
464 | ||
465 | /* C++ */ | |
466 | case OP_THIS: | |
467 | oplen = 2; | |
468 | break; | |
469 | ||
470 | default: | |
471 | args = 1 + ((int) opcode < (int) BINOP_END); | |
472 | } | |
473 | ||
474 | /* Copy the final operator itself, from the end of the input | |
475 | to the beginning of the output. */ | |
476 | inend -= oplen; | |
477 | bcopy (&inexpr->elts[inend], &outexpr->elts[outbeg], | |
478 | oplen * sizeof (union exp_element)); | |
479 | outbeg += oplen; | |
480 | ||
481 | /* Find the lengths of the arg subexpressions. */ | |
482 | arglens = (int *) alloca (args * sizeof (int)); | |
483 | for (i = args - 1; i >= 0; i--) | |
484 | { | |
485 | oplen = length_of_subexp (inexpr, inend); | |
486 | arglens[i] = oplen; | |
487 | inend -= oplen; | |
488 | } | |
489 | ||
490 | /* Now copy each subexpression, preserving the order of | |
491 | the subexpressions, but prefixifying each one. | |
492 | In this loop, inend starts at the beginning of | |
493 | the expression this level is working on | |
494 | and marches forward over the arguments. | |
495 | outbeg does similarly in the output. */ | |
496 | for (i = 0; i < args; i++) | |
497 | { | |
498 | oplen = arglens[i]; | |
499 | inend += oplen; | |
500 | prefixify_subexp (inexpr, outexpr, inend, outbeg); | |
501 | outbeg += oplen; | |
502 | } | |
503 | } | |
504 | \f | |
505 | /* This page contains the two entry points to this file. */ | |
506 | ||
507 | /* Read an expression from the string *STRINGPTR points to, | |
508 | parse it, and return a pointer to a struct expression that we malloc. | |
509 | Use block BLOCK as the lexical context for variable names; | |
510 | if BLOCK is zero, use the block of the selected stack frame. | |
511 | Meanwhile, advance *STRINGPTR to point after the expression, | |
512 | at the first nonwhite character that is not part of the expression | |
513 | (possibly a null character). | |
514 | ||
515 | If COMMA is nonzero, stop if a comma is reached. */ | |
516 | ||
517 | struct expression * | |
518 | parse_exp_1 (stringptr, block, comma) | |
519 | char **stringptr; | |
520 | struct block *block; | |
521 | int comma; | |
522 | { | |
523 | struct cleanup *old_chain; | |
524 | ||
525 | lexptr = *stringptr; | |
526 | ||
527 | paren_depth = 0; | |
528 | type_stack_depth = 0; | |
529 | ||
530 | comma_terminates = comma; | |
531 | ||
532 | if (lexptr == 0 || *lexptr == 0) | |
533 | error_no_arg ("expression to compute"); | |
534 | ||
535 | old_chain = make_cleanup (free_funcalls, 0); | |
536 | funcall_chain = 0; | |
537 | ||
538 | expression_context_block = block ? block : get_selected_block (); | |
539 | ||
540 | namecopy = (char *) alloca (strlen (lexptr) + 1); | |
541 | expout_size = 10; | |
542 | expout_ptr = 0; | |
543 | expout = (struct expression *) | |
544 | xmalloc (sizeof (struct expression) | |
545 | + expout_size * sizeof (union exp_element)); | |
546 | expout->language_defn = current_language; | |
547 | make_cleanup (free_current_contents, &expout); | |
548 | ||
549 | if (current_language->la_parser ()) | |
550 | current_language->la_error (NULL); | |
551 | ||
552 | discard_cleanups (old_chain); | |
553 | expout->nelts = expout_ptr; | |
554 | expout = (struct expression *) | |
555 | xrealloc (expout, | |
556 | sizeof (struct expression) | |
557 | + expout_ptr * sizeof (union exp_element)); | |
558 | prefixify_expression (expout); | |
559 | *stringptr = lexptr; | |
560 | return expout; | |
561 | } | |
562 | ||
563 | /* Parse STRING as an expression, and complain if this fails | |
564 | to use up all of the contents of STRING. */ | |
565 | ||
566 | struct expression * | |
567 | parse_expression (string) | |
568 | char *string; | |
569 | { | |
570 | register struct expression *exp; | |
571 | exp = parse_exp_1 (&string, 0, 0); | |
572 | if (*string) | |
573 | error ("Junk after end of expression."); | |
574 | return exp; | |
575 | } | |
576 | ||
577 | void | |
578 | push_type (tp) | |
579 | enum type_pieces tp; | |
580 | { | |
581 | if (type_stack_depth == type_stack_size) | |
582 | { | |
583 | type_stack_size *= 2; | |
584 | type_stack = (union type_stack_elt *) | |
585 | xrealloc (type_stack, type_stack_size * sizeof (*type_stack)); | |
586 | } | |
587 | type_stack[type_stack_depth++].piece = tp; | |
588 | } | |
589 | ||
590 | void | |
591 | push_type_int (n) | |
592 | int n; | |
593 | { | |
594 | if (type_stack_depth == type_stack_size) | |
595 | { | |
596 | type_stack_size *= 2; | |
597 | type_stack = (union type_stack_elt *) | |
598 | xrealloc (type_stack, type_stack_size * sizeof (*type_stack)); | |
599 | } | |
600 | type_stack[type_stack_depth++].int_val = n; | |
601 | } | |
602 | ||
603 | enum type_pieces | |
604 | pop_type () | |
605 | { | |
606 | if (type_stack_depth) | |
607 | return type_stack[--type_stack_depth].piece; | |
608 | return tp_end; | |
609 | } | |
610 | ||
611 | int | |
612 | pop_type_int () | |
613 | { | |
614 | if (type_stack_depth) | |
615 | return type_stack[--type_stack_depth].int_val; | |
616 | /* "Can't happen". */ | |
617 | return 0; | |
618 | } | |
619 | ||
620 | void | |
621 | _initialize_parse () | |
622 | { | |
623 | type_stack_size = 80; | |
624 | type_stack_depth = 0; | |
625 | type_stack = (union type_stack_elt *) | |
626 | xmalloc (type_stack_size * sizeof (*type_stack)); | |
627 | } |