1 /* Parse expressions for GDB.
3 Copyright (C) 1986-2017 Free Software Foundation, Inc.
5 Modified from expread.y by the Department of Computer Science at the
6 State University of New York at Buffalo, 1991.
8 This file is part of GDB.
10 This program is free software; you can redistribute it and/or modify
11 it under the terms of the GNU General Public License as published by
12 the Free Software Foundation; either version 3 of the License, or
13 (at your option) any later version.
15 This program is distributed in the hope that it will be useful,
16 but WITHOUT ANY WARRANTY; without even the implied warranty of
17 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 GNU General Public License for more details.
20 You should have received a copy of the GNU General Public License
21 along with this program. If not, see <http://www.gnu.org/licenses/>. */
23 /* Parse an expression from text in a string,
24 and return the result as a struct expression pointer.
25 That structure contains arithmetic operations in reverse polish,
26 with constants represented by operations that are followed by special data.
27 See expression.h for the details of the format.
28 What is important here is that it can be built up sequentially
29 during the process of parsing; the lower levels of the tree always
30 come first in the result. */
34 #include "arch-utils.h"
38 #include "expression.h"
43 #include "parser-defs.h"
45 #include "symfile.h" /* for overlay functions */
51 #include "user-regs.h"
53 #include "common/gdb_optional.h"
55 /* Standard set of definitions for printing, dumping, prefixifying,
56 * and evaluating expressions. */
58 const struct exp_descriptor exp_descriptor_standard =
60 print_subexp_standard,
61 operator_length_standard,
62 operator_check_standard,
64 dump_subexp_body_standard,
65 evaluate_subexp_standard
68 /* Global variables declared in parser-defs.h (and commented there). */
69 const struct block *expression_context_block;
70 CORE_ADDR expression_context_pc;
71 const struct block *innermost_block;
73 static struct type_stack type_stack;
75 const char *prev_lexptr;
79 /* True if parsing an expression to attempt completion. */
82 /* The index of the last struct expression directly before a '.' or
83 '->'. This is set when parsing and is only used when completing a
84 field name. It is -1 if no dereference operation was found. */
85 static int expout_last_struct = -1;
87 /* If we are completing a tagged type name, this will be nonzero. */
88 static enum type_code expout_tag_completion_type = TYPE_CODE_UNDEF;
90 /* The token for tagged type name completion. */
91 static char *expout_completion_name;
94 static unsigned int expressiondebug = 0;
96 show_expressiondebug (struct ui_file *file, int from_tty,
97 struct cmd_list_element *c, const char *value)
99 fprintf_filtered (file, _("Expression debugging is %s.\n"), value);
103 /* Non-zero if an expression parser should set yydebug. */
107 show_parserdebug (struct ui_file *file, int from_tty,
108 struct cmd_list_element *c, const char *value)
110 fprintf_filtered (file, _("Parser debugging is %s.\n"), value);
114 static void free_funcalls (void *ignore);
116 static int prefixify_subexp (struct expression *, struct expression *, int,
119 static expression_up parse_exp_in_context (const char **, CORE_ADDR,
120 const struct block *, int,
122 static expression_up parse_exp_in_context_1 (const char **, CORE_ADDR,
123 const struct block *, int,
126 void _initialize_parse (void);
128 /* Data structure for saving values of arglist_len for function calls whose
129 arguments contain other function calls. */
133 struct funcall *next;
137 static struct funcall *funcall_chain;
139 /* Begin counting arguments for a function call,
140 saving the data about any containing call. */
145 struct funcall *newobj;
147 newobj = XNEW (struct funcall);
148 newobj->next = funcall_chain;
149 newobj->arglist_len = arglist_len;
151 funcall_chain = newobj;
154 /* Return the number of arguments in a function call just terminated,
155 and restore the data for the containing function call. */
160 int val = arglist_len;
161 struct funcall *call = funcall_chain;
163 funcall_chain = call->next;
164 arglist_len = call->arglist_len;
169 /* Free everything in the funcall chain.
170 Used when there is an error inside parsing. */
173 free_funcalls (void *ignore)
175 struct funcall *call, *next;
177 for (call = funcall_chain; call; call = next)
185 /* See definition in parser-defs.h. */
188 initialize_expout (struct parser_state *ps, size_t initial_size,
189 const struct language_defn *lang,
190 struct gdbarch *gdbarch)
192 ps->expout_size = initial_size;
195 = (struct expression *) xmalloc (sizeof (struct expression)
196 + EXP_ELEM_TO_BYTES (ps->expout_size));
197 ps->expout->language_defn = lang;
198 ps->expout->gdbarch = gdbarch;
201 /* See definition in parser-defs.h. */
204 reallocate_expout (struct parser_state *ps)
206 /* Record the actual number of expression elements, and then
207 reallocate the expression memory so that we free up any
210 ps->expout->nelts = ps->expout_ptr;
211 ps->expout = (struct expression *)
212 xrealloc (ps->expout,
213 sizeof (struct expression)
214 + EXP_ELEM_TO_BYTES (ps->expout_ptr));
217 /* This page contains the functions for adding data to the struct expression
218 being constructed. */
220 /* Add one element to the end of the expression. */
222 /* To avoid a bug in the Sun 4 compiler, we pass things that can fit into
223 a register through here. */
226 write_exp_elt (struct parser_state *ps, const union exp_element *expelt)
228 if (ps->expout_ptr >= ps->expout_size)
230 ps->expout_size *= 2;
231 ps->expout = (struct expression *)
232 xrealloc (ps->expout, sizeof (struct expression)
233 + EXP_ELEM_TO_BYTES (ps->expout_size));
235 ps->expout->elts[ps->expout_ptr++] = *expelt;
239 write_exp_elt_opcode (struct parser_state *ps, enum exp_opcode expelt)
241 union exp_element tmp;
243 memset (&tmp, 0, sizeof (union exp_element));
245 write_exp_elt (ps, &tmp);
249 write_exp_elt_sym (struct parser_state *ps, struct symbol *expelt)
251 union exp_element tmp;
253 memset (&tmp, 0, sizeof (union exp_element));
255 write_exp_elt (ps, &tmp);
259 write_exp_elt_msym (struct parser_state *ps, minimal_symbol *expelt)
261 union exp_element tmp;
263 memset (&tmp, 0, sizeof (union exp_element));
264 tmp.msymbol = expelt;
265 write_exp_elt (ps, &tmp);
269 write_exp_elt_block (struct parser_state *ps, const struct block *b)
271 union exp_element tmp;
273 memset (&tmp, 0, sizeof (union exp_element));
275 write_exp_elt (ps, &tmp);
279 write_exp_elt_objfile (struct parser_state *ps, struct objfile *objfile)
281 union exp_element tmp;
283 memset (&tmp, 0, sizeof (union exp_element));
284 tmp.objfile = objfile;
285 write_exp_elt (ps, &tmp);
289 write_exp_elt_longcst (struct parser_state *ps, LONGEST expelt)
291 union exp_element tmp;
293 memset (&tmp, 0, sizeof (union exp_element));
294 tmp.longconst = expelt;
295 write_exp_elt (ps, &tmp);
299 write_exp_elt_dblcst (struct parser_state *ps, DOUBLEST expelt)
301 union exp_element tmp;
303 memset (&tmp, 0, sizeof (union exp_element));
304 tmp.doubleconst = expelt;
305 write_exp_elt (ps, &tmp);
309 write_exp_elt_decfloatcst (struct parser_state *ps, gdb_byte expelt[16])
311 union exp_element tmp;
314 for (index = 0; index < 16; index++)
315 tmp.decfloatconst[index] = expelt[index];
317 write_exp_elt (ps, &tmp);
321 write_exp_elt_type (struct parser_state *ps, struct type *expelt)
323 union exp_element tmp;
325 memset (&tmp, 0, sizeof (union exp_element));
327 write_exp_elt (ps, &tmp);
331 write_exp_elt_intern (struct parser_state *ps, struct internalvar *expelt)
333 union exp_element tmp;
335 memset (&tmp, 0, sizeof (union exp_element));
336 tmp.internalvar = expelt;
337 write_exp_elt (ps, &tmp);
340 /* Add a string constant to the end of the expression.
342 String constants are stored by first writing an expression element
343 that contains the length of the string, then stuffing the string
344 constant itself into however many expression elements are needed
345 to hold it, and then writing another expression element that contains
346 the length of the string. I.e. an expression element at each end of
347 the string records the string length, so you can skip over the
348 expression elements containing the actual string bytes from either
349 end of the string. Note that this also allows gdb to handle
350 strings with embedded null bytes, as is required for some languages.
352 Don't be fooled by the fact that the string is null byte terminated,
353 this is strictly for the convenience of debugging gdb itself.
354 Gdb does not depend up the string being null terminated, since the
355 actual length is recorded in expression elements at each end of the
356 string. The null byte is taken into consideration when computing how
357 many expression elements are required to hold the string constant, of
362 write_exp_string (struct parser_state *ps, struct stoken str)
364 int len = str.length;
368 /* Compute the number of expression elements required to hold the string
369 (including a null byte terminator), along with one expression element
370 at each end to record the actual string length (not including the
371 null byte terminator). */
373 lenelt = 2 + BYTES_TO_EXP_ELEM (len + 1);
375 increase_expout_size (ps, lenelt);
377 /* Write the leading length expression element (which advances the current
378 expression element index), then write the string constant followed by a
379 terminating null byte, and then write the trailing length expression
382 write_exp_elt_longcst (ps, (LONGEST) len);
383 strdata = (char *) &ps->expout->elts[ps->expout_ptr];
384 memcpy (strdata, str.ptr, len);
385 *(strdata + len) = '\0';
386 ps->expout_ptr += lenelt - 2;
387 write_exp_elt_longcst (ps, (LONGEST) len);
390 /* Add a vector of string constants to the end of the expression.
392 This adds an OP_STRING operation, but encodes the contents
393 differently from write_exp_string. The language is expected to
394 handle evaluation of this expression itself.
396 After the usual OP_STRING header, TYPE is written into the
397 expression as a long constant. The interpretation of this field is
398 up to the language evaluator.
400 Next, each string in VEC is written. The length is written as a
401 long constant, followed by the contents of the string. */
404 write_exp_string_vector (struct parser_state *ps, int type,
405 struct stoken_vector *vec)
410 /* Compute the size. We compute the size in number of slots to
411 avoid issues with string padding. */
413 for (i = 0; i < vec->len; ++i)
415 /* One slot for the length of this element, plus the number of
416 slots needed for this string. */
417 n_slots += 1 + BYTES_TO_EXP_ELEM (vec->tokens[i].length);
420 /* One more slot for the type of the string. */
423 /* Now compute a phony string length. */
424 len = EXP_ELEM_TO_BYTES (n_slots) - 1;
427 increase_expout_size (ps, n_slots);
429 write_exp_elt_opcode (ps, OP_STRING);
430 write_exp_elt_longcst (ps, len);
431 write_exp_elt_longcst (ps, type);
433 for (i = 0; i < vec->len; ++i)
435 write_exp_elt_longcst (ps, vec->tokens[i].length);
436 memcpy (&ps->expout->elts[ps->expout_ptr], vec->tokens[i].ptr,
437 vec->tokens[i].length);
438 ps->expout_ptr += BYTES_TO_EXP_ELEM (vec->tokens[i].length);
441 write_exp_elt_longcst (ps, len);
442 write_exp_elt_opcode (ps, OP_STRING);
445 /* Add a bitstring constant to the end of the expression.
447 Bitstring constants are stored by first writing an expression element
448 that contains the length of the bitstring (in bits), then stuffing the
449 bitstring constant itself into however many expression elements are
450 needed to hold it, and then writing another expression element that
451 contains the length of the bitstring. I.e. an expression element at
452 each end of the bitstring records the bitstring length, so you can skip
453 over the expression elements containing the actual bitstring bytes from
454 either end of the bitstring. */
457 write_exp_bitstring (struct parser_state *ps, struct stoken str)
459 int bits = str.length; /* length in bits */
460 int len = (bits + HOST_CHAR_BIT - 1) / HOST_CHAR_BIT;
464 /* Compute the number of expression elements required to hold the bitstring,
465 along with one expression element at each end to record the actual
466 bitstring length in bits. */
468 lenelt = 2 + BYTES_TO_EXP_ELEM (len);
470 increase_expout_size (ps, lenelt);
472 /* Write the leading length expression element (which advances the current
473 expression element index), then write the bitstring constant, and then
474 write the trailing length expression element. */
476 write_exp_elt_longcst (ps, (LONGEST) bits);
477 strdata = (char *) &ps->expout->elts[ps->expout_ptr];
478 memcpy (strdata, str.ptr, len);
479 ps->expout_ptr += lenelt - 2;
480 write_exp_elt_longcst (ps, (LONGEST) bits);
483 /* Return the type of MSYMBOL, a minimal symbol of OBJFILE. If
484 ADDRESS_P is not NULL, set it to the MSYMBOL's resolved
488 find_minsym_type_and_address (minimal_symbol *msymbol,
489 struct objfile *objfile,
490 CORE_ADDR *address_p)
492 bound_minimal_symbol bound_msym = {msymbol, objfile};
493 struct gdbarch *gdbarch = get_objfile_arch (objfile);
494 struct obj_section *section = MSYMBOL_OBJ_SECTION (objfile, msymbol);
495 enum minimal_symbol_type type = MSYMBOL_TYPE (msymbol);
498 bool is_tls = (section != NULL
499 && section->the_bfd_section->flags & SEC_THREAD_LOCAL);
501 /* Addresses of TLS symbols are really offsets into a
502 per-objfile/per-thread storage block. */
503 CORE_ADDR addr = (is_tls
504 ? MSYMBOL_VALUE_RAW_ADDRESS (bound_msym.minsym)
505 : BMSYMBOL_VALUE_ADDRESS (bound_msym));
507 /* The minimal symbol might point to a function descriptor;
508 resolve it to the actual code address instead. */
509 pc = gdbarch_convert_from_func_ptr_addr (gdbarch, addr, ¤t_target);
512 struct bound_minimal_symbol ifunc_msym = lookup_minimal_symbol_by_pc (pc);
514 /* In this case, assume we have a code symbol instead of
517 if (ifunc_msym.minsym != NULL
518 && MSYMBOL_TYPE (ifunc_msym.minsym) == mst_text_gnu_ifunc
519 && BMSYMBOL_VALUE_ADDRESS (ifunc_msym) == pc)
521 /* A function descriptor has been resolved but PC is still in the
522 STT_GNU_IFUNC resolver body (such as because inferior does not
523 run to be able to call it). */
525 type = mst_text_gnu_ifunc;
533 if (overlay_debugging)
534 addr = symbol_overlayed_address (addr, section);
538 /* Skip translation if caller does not need the address. */
539 if (address_p != NULL)
540 *address_p = target_translate_tls_address (objfile, addr);
541 return objfile_type (objfile)->nodebug_tls_symbol;
544 if (address_p != NULL)
547 struct type *the_type;
553 case mst_solib_trampoline:
554 return objfile_type (objfile)->nodebug_text_symbol;
556 case mst_text_gnu_ifunc:
557 return objfile_type (objfile)->nodebug_text_gnu_ifunc_symbol;
563 return objfile_type (objfile)->nodebug_data_symbol;
565 case mst_slot_got_plt:
566 return objfile_type (objfile)->nodebug_got_plt_symbol;
569 return objfile_type (objfile)->nodebug_unknown_symbol;
573 /* Add the appropriate elements for a minimal symbol to the end of
577 write_exp_msymbol (struct parser_state *ps,
578 struct bound_minimal_symbol bound_msym)
580 write_exp_elt_opcode (ps, OP_VAR_MSYM_VALUE);
581 write_exp_elt_objfile (ps, bound_msym.objfile);
582 write_exp_elt_msym (ps, bound_msym.minsym);
583 write_exp_elt_opcode (ps, OP_VAR_MSYM_VALUE);
586 /* Mark the current index as the starting location of a structure
587 expression. This is used when completing on field names. */
590 mark_struct_expression (struct parser_state *ps)
592 gdb_assert (parse_completion
593 && expout_tag_completion_type == TYPE_CODE_UNDEF);
594 expout_last_struct = ps->expout_ptr;
597 /* Indicate that the current parser invocation is completing a tag.
598 TAG is the type code of the tag, and PTR and LENGTH represent the
599 start of the tag name. */
602 mark_completion_tag (enum type_code tag, const char *ptr, int length)
604 gdb_assert (parse_completion
605 && expout_tag_completion_type == TYPE_CODE_UNDEF
606 && expout_completion_name == NULL
607 && expout_last_struct == -1);
608 gdb_assert (tag == TYPE_CODE_UNION
609 || tag == TYPE_CODE_STRUCT
610 || tag == TYPE_CODE_ENUM);
611 expout_tag_completion_type = tag;
612 expout_completion_name = (char *) xmalloc (length + 1);
613 memcpy (expout_completion_name, ptr, length);
614 expout_completion_name[length] = '\0';
618 /* Recognize tokens that start with '$'. These include:
620 $regname A native register name or a "standard
623 $variable A convenience variable with a name chosen
626 $digits Value history with index <digits>, starting
627 from the first value which has index 1.
629 $$digits Value history with index <digits> relative
630 to the last value. I.e. $$0 is the last
631 value, $$1 is the one previous to that, $$2
632 is the one previous to $$1, etc.
634 $ | $0 | $$0 The last value in the value history.
636 $$ An abbreviation for the second to the last
637 value in the value history, I.e. $$1 */
640 write_dollar_variable (struct parser_state *ps, struct stoken str)
642 struct block_symbol sym;
643 struct bound_minimal_symbol msym;
644 struct internalvar *isym = NULL;
646 /* Handle the tokens $digits; also $ (short for $0) and $$ (short for $$1)
647 and $$digits (equivalent to $<-digits> if you could type that). */
651 /* Double dollar means negate the number and add -1 as well.
652 Thus $$ alone means -1. */
653 if (str.length >= 2 && str.ptr[1] == '$')
660 /* Just dollars (one or two). */
664 /* Is the rest of the token digits? */
665 for (; i < str.length; i++)
666 if (!(str.ptr[i] >= '0' && str.ptr[i] <= '9'))
670 i = atoi (str.ptr + 1 + negate);
676 /* Handle tokens that refer to machine registers:
677 $ followed by a register name. */
678 i = user_reg_map_name_to_regnum (parse_gdbarch (ps),
679 str.ptr + 1, str.length - 1);
681 goto handle_register;
683 /* Any names starting with $ are probably debugger internal variables. */
685 isym = lookup_only_internalvar (copy_name (str) + 1);
688 write_exp_elt_opcode (ps, OP_INTERNALVAR);
689 write_exp_elt_intern (ps, isym);
690 write_exp_elt_opcode (ps, OP_INTERNALVAR);
694 /* On some systems, such as HP-UX and hppa-linux, certain system routines
695 have names beginning with $ or $$. Check for those, first. */
697 sym = lookup_symbol (copy_name (str), (struct block *) NULL,
701 write_exp_elt_opcode (ps, OP_VAR_VALUE);
702 write_exp_elt_block (ps, sym.block);
703 write_exp_elt_sym (ps, sym.symbol);
704 write_exp_elt_opcode (ps, OP_VAR_VALUE);
707 msym = lookup_bound_minimal_symbol (copy_name (str));
710 write_exp_msymbol (ps, msym);
714 /* Any other names are assumed to be debugger internal variables. */
716 write_exp_elt_opcode (ps, OP_INTERNALVAR);
717 write_exp_elt_intern (ps, create_internalvar (copy_name (str) + 1));
718 write_exp_elt_opcode (ps, OP_INTERNALVAR);
721 write_exp_elt_opcode (ps, OP_LAST);
722 write_exp_elt_longcst (ps, (LONGEST) i);
723 write_exp_elt_opcode (ps, OP_LAST);
726 write_exp_elt_opcode (ps, OP_REGISTER);
729 write_exp_string (ps, str);
730 write_exp_elt_opcode (ps, OP_REGISTER);
736 find_template_name_end (const char *p)
739 int just_seen_right = 0;
740 int just_seen_colon = 0;
741 int just_seen_space = 0;
743 if (!p || (*p != '<'))
754 /* In future, may want to allow these?? */
757 depth++; /* start nested template */
758 if (just_seen_colon || just_seen_right || just_seen_space)
759 return 0; /* but not after : or :: or > or space */
762 if (just_seen_colon || just_seen_right)
763 return 0; /* end a (nested?) template */
764 just_seen_right = 1; /* but not after : or :: */
765 if (--depth == 0) /* also disallow >>, insist on > > */
766 return ++p; /* if outermost ended, return */
769 if (just_seen_space || (just_seen_colon > 1))
770 return 0; /* nested class spec coming up */
771 just_seen_colon++; /* we allow :: but not :::: */
776 if (!((*p >= 'a' && *p <= 'z') || /* allow token chars */
777 (*p >= 'A' && *p <= 'Z') ||
778 (*p >= '0' && *p <= '9') ||
779 (*p == '_') || (*p == ',') || /* commas for template args */
780 (*p == '&') || (*p == '*') || /* pointer and ref types */
781 (*p == '(') || (*p == ')') || /* function types */
782 (*p == '[') || (*p == ']'))) /* array types */
796 /* Return a null-terminated temporary copy of the name of a string token.
798 Tokens that refer to names do so with explicit pointer and length,
799 so they can share the storage that lexptr is parsing.
800 When it is necessary to pass a name to a function that expects
801 a null-terminated string, the substring is copied out
802 into a separate block of storage.
804 N.B. A single buffer is reused on each call. */
807 copy_name (struct stoken token)
809 /* A temporary buffer for identifiers, so we can null-terminate them.
810 We allocate this with xrealloc. parse_exp_1 used to allocate with
811 alloca, using the size of the whole expression as a conservative
812 estimate of the space needed. However, macro expansion can
813 introduce names longer than the original expression; there's no
814 practical way to know beforehand how large that might be. */
815 static char *namecopy;
816 static size_t namecopy_size;
818 /* Make sure there's enough space for the token. */
819 if (namecopy_size < token.length + 1)
821 namecopy_size = token.length + 1;
822 namecopy = (char *) xrealloc (namecopy, token.length + 1);
825 memcpy (namecopy, token.ptr, token.length);
826 namecopy[token.length] = 0;
832 /* See comments on parser-defs.h. */
835 prefixify_expression (struct expression *expr)
837 int len = sizeof (struct expression) + EXP_ELEM_TO_BYTES (expr->nelts);
838 struct expression *temp;
839 int inpos = expr->nelts, outpos = 0;
841 temp = (struct expression *) alloca (len);
843 /* Copy the original expression into temp. */
844 memcpy (temp, expr, len);
846 return prefixify_subexp (temp, expr, inpos, outpos);
849 /* Return the number of exp_elements in the postfix subexpression
850 of EXPR whose operator is at index ENDPOS - 1 in EXPR. */
853 length_of_subexp (struct expression *expr, int endpos)
857 operator_length (expr, endpos, &oplen, &args);
861 oplen += length_of_subexp (expr, endpos - oplen);
868 /* Sets *OPLENP to the length of the operator whose (last) index is
869 ENDPOS - 1 in EXPR, and sets *ARGSP to the number of arguments that
873 operator_length (const struct expression *expr, int endpos, int *oplenp,
876 expr->language_defn->la_exp_desc->operator_length (expr, endpos,
880 /* Default value for operator_length in exp_descriptor vectors. */
883 operator_length_standard (const struct expression *expr, int endpos,
884 int *oplenp, int *argsp)
888 enum range_type range_type;
892 error (_("?error in operator_length_standard"));
894 i = (int) expr->elts[endpos - 1].opcode;
900 oplen = longest_to_int (expr->elts[endpos - 2].longconst);
901 oplen = 5 + BYTES_TO_EXP_ELEM (oplen + 1);
908 case OP_VAR_MSYM_VALUE:
912 case OP_FUNC_STATIC_VAR:
913 oplen = longest_to_int (expr->elts[endpos - 2].longconst);
914 oplen = 4 + BYTES_TO_EXP_ELEM (oplen + 1);
922 case OP_VAR_ENTRY_VALUE:
932 case OP_F77_UNDETERMINED_ARGLIST:
934 args = 1 + longest_to_int (expr->elts[endpos - 2].longconst);
938 oplen = 5 + longest_to_int (expr->elts[endpos - 2].longconst);
942 case OP_OBJC_MSGCALL: /* Objective C message (method) call. */
944 args = 1 + longest_to_int (expr->elts[endpos - 2].longconst);
953 case UNOP_DYNAMIC_CAST:
954 case UNOP_REINTERPRET_CAST:
955 case UNOP_MEMVAL_TYPE:
983 oplen = longest_to_int (expr->elts[endpos - 2].longconst);
984 oplen = 4 + BYTES_TO_EXP_ELEM (oplen + 1);
989 case STRUCTOP_STRUCT:
996 case OP_OBJC_NSSTRING: /* Objective C Foundation Class
997 NSString constant. */
998 case OP_OBJC_SELECTOR: /* Objective C "@selector" pseudo-op. */
1000 oplen = longest_to_int (expr->elts[endpos - 2].longconst);
1001 oplen = 4 + BYTES_TO_EXP_ELEM (oplen + 1);
1006 args = longest_to_int (expr->elts[endpos - 2].longconst);
1007 args -= longest_to_int (expr->elts[endpos - 3].longconst);
1017 case MULTI_SUBSCRIPT:
1019 args = 1 + longest_to_int (expr->elts[endpos - 2].longconst);
1022 case BINOP_ASSIGN_MODIFY:
1034 range_type = (enum range_type)
1035 longest_to_int (expr->elts[endpos - 2].longconst);
1039 case LOW_BOUND_DEFAULT:
1040 case HIGH_BOUND_DEFAULT:
1043 case BOTH_BOUND_DEFAULT:
1046 case NONE_BOUND_DEFAULT:
1054 args = 1 + (i < (int) BINOP_END);
1061 /* Copy the subexpression ending just before index INEND in INEXPR
1062 into OUTEXPR, starting at index OUTBEG.
1063 In the process, convert it from suffix to prefix form.
1064 If EXPOUT_LAST_STRUCT is -1, then this function always returns -1.
1065 Otherwise, it returns the index of the subexpression which is the
1066 left-hand-side of the expression at EXPOUT_LAST_STRUCT. */
1069 prefixify_subexp (struct expression *inexpr,
1070 struct expression *outexpr, int inend, int outbeg)
1078 operator_length (inexpr, inend, &oplen, &args);
1080 /* Copy the final operator itself, from the end of the input
1081 to the beginning of the output. */
1083 memcpy (&outexpr->elts[outbeg], &inexpr->elts[inend],
1084 EXP_ELEM_TO_BYTES (oplen));
1087 if (expout_last_struct == inend)
1088 result = outbeg - oplen;
1090 /* Find the lengths of the arg subexpressions. */
1091 arglens = (int *) alloca (args * sizeof (int));
1092 for (i = args - 1; i >= 0; i--)
1094 oplen = length_of_subexp (inexpr, inend);
1099 /* Now copy each subexpression, preserving the order of
1100 the subexpressions, but prefixifying each one.
1101 In this loop, inend starts at the beginning of
1102 the expression this level is working on
1103 and marches forward over the arguments.
1104 outbeg does similarly in the output. */
1105 for (i = 0; i < args; i++)
1111 r = prefixify_subexp (inexpr, outexpr, inend, outbeg);
1114 /* Return immediately. We probably have only parsed a
1115 partial expression, so we don't want to try to reverse
1116 the other operands. */
1125 /* Read an expression from the string *STRINGPTR points to,
1126 parse it, and return a pointer to a struct expression that we malloc.
1127 Use block BLOCK as the lexical context for variable names;
1128 if BLOCK is zero, use the block of the selected stack frame.
1129 Meanwhile, advance *STRINGPTR to point after the expression,
1130 at the first nonwhite character that is not part of the expression
1131 (possibly a null character).
1133 If COMMA is nonzero, stop if a comma is reached. */
1136 parse_exp_1 (const char **stringptr, CORE_ADDR pc, const struct block *block,
1139 return parse_exp_in_context (stringptr, pc, block, comma, 0, NULL);
1142 static expression_up
1143 parse_exp_in_context (const char **stringptr, CORE_ADDR pc,
1144 const struct block *block,
1145 int comma, int void_context_p, int *out_subexp)
1147 return parse_exp_in_context_1 (stringptr, pc, block, comma,
1148 void_context_p, out_subexp);
1151 /* As for parse_exp_1, except that if VOID_CONTEXT_P, then
1152 no value is expected from the expression.
1153 OUT_SUBEXP is set when attempting to complete a field name; in this
1154 case it is set to the index of the subexpression on the
1155 left-hand-side of the struct op. If not doing such completion, it
1156 is left untouched. */
1158 static expression_up
1159 parse_exp_in_context_1 (const char **stringptr, CORE_ADDR pc,
1160 const struct block *block,
1161 int comma, int void_context_p, int *out_subexp)
1163 struct cleanup *old_chain;
1164 const struct language_defn *lang = NULL;
1165 struct parser_state ps;
1168 lexptr = *stringptr;
1172 type_stack.depth = 0;
1173 expout_last_struct = -1;
1174 expout_tag_completion_type = TYPE_CODE_UNDEF;
1175 xfree (expout_completion_name);
1176 expout_completion_name = NULL;
1178 comma_terminates = comma;
1180 if (lexptr == 0 || *lexptr == 0)
1181 error_no_arg (_("expression to compute"));
1183 old_chain = make_cleanup (free_funcalls, 0 /*ignore*/);
1186 expression_context_block = block;
1188 /* If no context specified, try using the current frame, if any. */
1189 if (!expression_context_block)
1190 expression_context_block = get_selected_block (&expression_context_pc);
1192 expression_context_pc = BLOCK_START (expression_context_block);
1194 expression_context_pc = pc;
1196 /* Fall back to using the current source static context, if any. */
1198 if (!expression_context_block)
1200 struct symtab_and_line cursal = get_current_source_symtab_and_line ();
1202 expression_context_block
1203 = BLOCKVECTOR_BLOCK (SYMTAB_BLOCKVECTOR (cursal.symtab),
1205 if (expression_context_block)
1206 expression_context_pc = BLOCK_START (expression_context_block);
1209 if (language_mode == language_mode_auto && block != NULL)
1211 /* Find the language associated to the given context block.
1212 Default to the current language if it can not be determined.
1214 Note that using the language corresponding to the current frame
1215 can sometimes give unexpected results. For instance, this
1216 routine is often called several times during the inferior
1217 startup phase to re-parse breakpoint expressions after
1218 a new shared library has been loaded. The language associated
1219 to the current frame at this moment is not relevant for
1220 the breakpoint. Using it would therefore be silly, so it seems
1221 better to rely on the current language rather than relying on
1222 the current frame language to parse the expression. That's why
1223 we do the following language detection only if the context block
1224 has been specifically provided. */
1225 struct symbol *func = block_linkage_function (block);
1228 lang = language_def (SYMBOL_LANGUAGE (func));
1229 if (lang == NULL || lang->la_language == language_unknown)
1230 lang = current_language;
1233 lang = current_language;
1235 /* get_current_arch may reset CURRENT_LANGUAGE via select_frame.
1236 While we need CURRENT_LANGUAGE to be set to LANG (for lookup_symbol
1237 and others called from *.y) ensure CURRENT_LANGUAGE gets restored
1238 to the value matching SELECTED_FRAME as set by get_current_arch. */
1240 initialize_expout (&ps, 10, lang, get_current_arch ());
1242 scoped_restore_current_language lang_saver;
1243 set_language (lang->la_language);
1247 if (lang->la_parser (&ps))
1248 lang->la_error (NULL);
1250 CATCH (except, RETURN_MASK_ALL)
1252 if (! parse_completion)
1255 throw_exception (except);
1260 reallocate_expout (&ps);
1262 /* Convert expression from postfix form as generated by yacc
1263 parser, to a prefix form. */
1265 if (expressiondebug)
1266 dump_raw_expression (ps.expout, gdb_stdlog,
1267 "before conversion to prefix form");
1269 subexp = prefixify_expression (ps.expout);
1271 *out_subexp = subexp;
1273 lang->la_post_parser (&ps.expout, void_context_p);
1275 if (expressiondebug)
1276 dump_prefix_expression (ps.expout, gdb_stdlog);
1278 discard_cleanups (old_chain);
1280 *stringptr = lexptr;
1281 return expression_up (ps.expout);
1284 /* Parse STRING as an expression, and complain if this fails
1285 to use up all of the contents of STRING. */
1288 parse_expression (const char *string)
1290 expression_up exp = parse_exp_1 (&string, 0, 0, 0);
1292 error (_("Junk after end of expression."));
1296 /* Same as parse_expression, but using the given language (LANG)
1297 to parse the expression. */
1300 parse_expression_with_language (const char *string, enum language lang)
1302 gdb::optional<scoped_restore_current_language> lang_saver;
1303 if (current_language->la_language != lang)
1305 lang_saver.emplace ();
1306 set_language (lang);
1309 return parse_expression (string);
1312 /* Parse STRING as an expression. If parsing ends in the middle of a
1313 field reference, return the type of the left-hand-side of the
1314 reference; furthermore, if the parsing ends in the field name,
1315 return the field name in *NAME. If the parsing ends in the middle
1316 of a field reference, but the reference is somehow invalid, throw
1317 an exception. In all other cases, return NULL. Returned non-NULL
1318 *NAME must be freed by the caller. */
1321 parse_expression_for_completion (const char *string, char **name,
1322 enum type_code *code)
1330 parse_completion = 1;
1331 exp = parse_exp_in_context (&string, 0, 0, 0, 0, &subexp);
1333 CATCH (except, RETURN_MASK_ERROR)
1335 /* Nothing, EXP remains NULL. */
1339 parse_completion = 0;
1343 if (expout_tag_completion_type != TYPE_CODE_UNDEF)
1345 *code = expout_tag_completion_type;
1346 *name = expout_completion_name;
1347 expout_completion_name = NULL;
1351 if (expout_last_struct == -1)
1354 *name = extract_field_op (exp.get (), &subexp);
1358 /* This might throw an exception. If so, we want to let it
1360 val = evaluate_subexpression_type (exp.get (), subexp);
1361 /* (*NAME) is a part of the EXP memory block freed below. */
1362 *name = xstrdup (*name);
1364 return value_type (val);
1367 /* A post-parser that does nothing. */
1370 null_post_parser (struct expression **exp, int void_context_p)
1374 /* Parse floating point value P of length LEN.
1375 Return 0 (false) if invalid, 1 (true) if valid.
1376 The successfully parsed number is stored in D.
1377 *SUFFIX points to the suffix of the number in P.
1379 NOTE: This accepts the floating point syntax that sscanf accepts. */
1382 parse_float (const char *p, int len, DOUBLEST *d, const char **suffix)
1387 copy = (char *) xmalloc (len + 1);
1388 memcpy (copy, p, len);
1391 num = sscanf (copy, "%" DOUBLEST_SCAN_FORMAT "%n", d, &n);
1394 /* The sscanf man page suggests not making any assumptions on the effect
1395 of %n on the result, so we don't.
1396 That is why we simply test num == 0. */
1404 /* Parse floating point value P of length LEN, using the C syntax for floats.
1405 Return 0 (false) if invalid, 1 (true) if valid.
1406 The successfully parsed number is stored in *D.
1407 Its type is taken from builtin_type (gdbarch) and is stored in *T. */
1410 parse_c_float (struct gdbarch *gdbarch, const char *p, int len,
1411 DOUBLEST *d, struct type **t)
1415 const struct builtin_type *builtin_types = builtin_type (gdbarch);
1417 if (! parse_float (p, len, d, &suffix))
1420 suffix_len = p + len - suffix;
1422 if (suffix_len == 0)
1423 *t = builtin_types->builtin_double;
1424 else if (suffix_len == 1)
1426 /* Handle suffixes: 'f' for float, 'l' for long double. */
1427 if (tolower (*suffix) == 'f')
1428 *t = builtin_types->builtin_float;
1429 else if (tolower (*suffix) == 'l')
1430 *t = builtin_types->builtin_long_double;
1440 /* Stuff for maintaining a stack of types. Currently just used by C, but
1441 probably useful for any language which declares its types "backwards". */
1443 /* Ensure that there are HOWMUCH open slots on the type stack STACK. */
1446 type_stack_reserve (struct type_stack *stack, int howmuch)
1448 if (stack->depth + howmuch >= stack->size)
1451 if (stack->size < howmuch)
1452 stack->size = howmuch;
1453 stack->elements = XRESIZEVEC (union type_stack_elt, stack->elements,
1458 /* Ensure that there is a single open slot in the global type stack. */
1461 check_type_stack_depth (void)
1463 type_stack_reserve (&type_stack, 1);
1466 /* A helper function for insert_type and insert_type_address_space.
1467 This does work of expanding the type stack and inserting the new
1468 element, ELEMENT, into the stack at location SLOT. */
1471 insert_into_type_stack (int slot, union type_stack_elt element)
1473 check_type_stack_depth ();
1475 if (slot < type_stack.depth)
1476 memmove (&type_stack.elements[slot + 1], &type_stack.elements[slot],
1477 (type_stack.depth - slot) * sizeof (union type_stack_elt));
1478 type_stack.elements[slot] = element;
1482 /* Insert a new type, TP, at the bottom of the type stack. If TP is
1483 tp_pointer, tp_reference or tp_rvalue_reference, it is inserted at the
1484 bottom. If TP is a qualifier, it is inserted at slot 1 (just above a
1485 previous tp_pointer) if there is anything on the stack, or simply pushed
1486 if the stack is empty. Other values for TP are invalid. */
1489 insert_type (enum type_pieces tp)
1491 union type_stack_elt element;
1494 gdb_assert (tp == tp_pointer || tp == tp_reference
1495 || tp == tp_rvalue_reference || tp == tp_const
1496 || tp == tp_volatile);
1498 /* If there is anything on the stack (we know it will be a
1499 tp_pointer), insert the qualifier above it. Otherwise, simply
1500 push this on the top of the stack. */
1501 if (type_stack.depth && (tp == tp_const || tp == tp_volatile))
1507 insert_into_type_stack (slot, element);
1511 push_type (enum type_pieces tp)
1513 check_type_stack_depth ();
1514 type_stack.elements[type_stack.depth++].piece = tp;
1518 push_type_int (int n)
1520 check_type_stack_depth ();
1521 type_stack.elements[type_stack.depth++].int_val = n;
1524 /* Insert a tp_space_identifier and the corresponding address space
1525 value into the stack. STRING is the name of an address space, as
1526 recognized by address_space_name_to_int. If the stack is empty,
1527 the new elements are simply pushed. If the stack is not empty,
1528 this function assumes that the first item on the stack is a
1529 tp_pointer, and the new values are inserted above the first
1533 insert_type_address_space (struct parser_state *pstate, char *string)
1535 union type_stack_elt element;
1538 /* If there is anything on the stack (we know it will be a
1539 tp_pointer), insert the address space qualifier above it.
1540 Otherwise, simply push this on the top of the stack. */
1541 if (type_stack.depth)
1546 element.piece = tp_space_identifier;
1547 insert_into_type_stack (slot, element);
1548 element.int_val = address_space_name_to_int (parse_gdbarch (pstate),
1550 insert_into_type_stack (slot, element);
1556 if (type_stack.depth)
1557 return type_stack.elements[--type_stack.depth].piece;
1564 if (type_stack.depth)
1565 return type_stack.elements[--type_stack.depth].int_val;
1566 /* "Can't happen". */
1570 /* Pop a type list element from the global type stack. */
1572 static VEC (type_ptr) *
1575 gdb_assert (type_stack.depth);
1576 return type_stack.elements[--type_stack.depth].typelist_val;
1579 /* Pop a type_stack element from the global type stack. */
1581 static struct type_stack *
1582 pop_type_stack (void)
1584 gdb_assert (type_stack.depth);
1585 return type_stack.elements[--type_stack.depth].stack_val;
1588 /* Append the elements of the type stack FROM to the type stack TO.
1589 Always returns TO. */
1592 append_type_stack (struct type_stack *to, struct type_stack *from)
1594 type_stack_reserve (to, from->depth);
1596 memcpy (&to->elements[to->depth], &from->elements[0],
1597 from->depth * sizeof (union type_stack_elt));
1598 to->depth += from->depth;
1603 /* Push the type stack STACK as an element on the global type stack. */
1606 push_type_stack (struct type_stack *stack)
1608 check_type_stack_depth ();
1609 type_stack.elements[type_stack.depth++].stack_val = stack;
1610 push_type (tp_type_stack);
1613 /* Copy the global type stack into a newly allocated type stack and
1614 return it. The global stack is cleared. The returned type stack
1615 must be freed with type_stack_cleanup. */
1618 get_type_stack (void)
1620 struct type_stack *result = XNEW (struct type_stack);
1622 *result = type_stack;
1623 type_stack.depth = 0;
1624 type_stack.size = 0;
1625 type_stack.elements = NULL;
1630 /* A cleanup function that destroys a single type stack. */
1633 type_stack_cleanup (void *arg)
1635 struct type_stack *stack = (struct type_stack *) arg;
1637 xfree (stack->elements);
1641 /* Push a function type with arguments onto the global type stack.
1642 LIST holds the argument types. If the final item in LIST is NULL,
1643 then the function will be varargs. */
1646 push_typelist (VEC (type_ptr) *list)
1648 check_type_stack_depth ();
1649 type_stack.elements[type_stack.depth++].typelist_val = list;
1650 push_type (tp_function_with_arguments);
1653 /* Pop the type stack and return a type_instance_flags that
1654 corresponds the const/volatile qualifiers on the stack. This is
1655 called by the C++ parser when parsing methods types, and as such no
1656 other kind of type in the type stack is expected. */
1659 follow_type_instance_flags ()
1661 type_instance_flags flags = 0;
1664 switch (pop_type ())
1669 flags |= TYPE_INSTANCE_FLAG_CONST;
1672 flags |= TYPE_INSTANCE_FLAG_VOLATILE;
1675 gdb_assert_not_reached ("unrecognized tp_ value in follow_types");
1680 /* Pop the type stack and return the type which corresponds to FOLLOW_TYPE
1681 as modified by all the stuff on the stack. */
1683 follow_types (struct type *follow_type)
1687 int make_volatile = 0;
1688 int make_addr_space = 0;
1692 switch (pop_type ())
1697 follow_type = make_cv_type (make_const,
1698 TYPE_VOLATILE (follow_type),
1701 follow_type = make_cv_type (TYPE_CONST (follow_type),
1704 if (make_addr_space)
1705 follow_type = make_type_with_address_space (follow_type,
1707 make_const = make_volatile = 0;
1708 make_addr_space = 0;
1716 case tp_space_identifier:
1717 make_addr_space = pop_type_int ();
1720 follow_type = lookup_pointer_type (follow_type);
1722 follow_type = make_cv_type (make_const,
1723 TYPE_VOLATILE (follow_type),
1726 follow_type = make_cv_type (TYPE_CONST (follow_type),
1729 if (make_addr_space)
1730 follow_type = make_type_with_address_space (follow_type,
1732 make_const = make_volatile = 0;
1733 make_addr_space = 0;
1736 follow_type = lookup_lvalue_reference_type (follow_type);
1737 goto process_reference;
1738 case tp_rvalue_reference:
1739 follow_type = lookup_rvalue_reference_type (follow_type);
1742 follow_type = make_cv_type (make_const,
1743 TYPE_VOLATILE (follow_type),
1746 follow_type = make_cv_type (TYPE_CONST (follow_type),
1749 if (make_addr_space)
1750 follow_type = make_type_with_address_space (follow_type,
1752 make_const = make_volatile = 0;
1753 make_addr_space = 0;
1756 array_size = pop_type_int ();
1757 /* FIXME-type-allocation: need a way to free this type when we are
1760 lookup_array_range_type (follow_type,
1761 0, array_size >= 0 ? array_size - 1 : 0);
1763 TYPE_HIGH_BOUND_KIND (TYPE_INDEX_TYPE (follow_type))
1767 /* FIXME-type-allocation: need a way to free this type when we are
1769 follow_type = lookup_function_type (follow_type);
1772 case tp_function_with_arguments:
1774 VEC (type_ptr) *args = pop_typelist ();
1777 = lookup_function_type_with_arguments (follow_type,
1778 VEC_length (type_ptr, args),
1779 VEC_address (type_ptr,
1781 VEC_free (type_ptr, args);
1787 struct type_stack *stack = pop_type_stack ();
1788 /* Sort of ugly, but not really much worse than the
1790 struct type_stack save = type_stack;
1792 type_stack = *stack;
1793 follow_type = follow_types (follow_type);
1794 gdb_assert (type_stack.depth == 0);
1800 gdb_assert_not_reached ("unrecognized tp_ value in follow_types");
1805 /* This function avoids direct calls to fprintf
1806 in the parser generated debug code. */
1808 parser_fprintf (FILE *x, const char *y, ...)
1814 vfprintf_unfiltered (gdb_stderr, y, args);
1817 fprintf_unfiltered (gdb_stderr, " Unknown FILE used.\n");
1818 vfprintf_unfiltered (gdb_stderr, y, args);
1823 /* Implementation of the exp_descriptor method operator_check. */
1826 operator_check_standard (struct expression *exp, int pos,
1827 int (*objfile_func) (struct objfile *objfile,
1831 const union exp_element *const elts = exp->elts;
1832 struct type *type = NULL;
1833 struct objfile *objfile = NULL;
1835 /* Extended operators should have been already handled by exp_descriptor
1836 iterate method of its specific language. */
1837 gdb_assert (elts[pos].opcode < OP_EXTENDED0);
1839 /* Track the callers of write_exp_elt_type for this table. */
1841 switch (elts[pos].opcode)
1854 type = elts[pos + 1].type;
1859 LONGEST arg, nargs = elts[pos + 2].longconst;
1861 for (arg = 0; arg < nargs; arg++)
1863 struct type *type = elts[pos + 3 + arg].type;
1864 struct objfile *objfile = TYPE_OBJFILE (type);
1866 if (objfile && (*objfile_func) (objfile, data))
1874 const struct block *const block = elts[pos + 1].block;
1875 const struct symbol *const symbol = elts[pos + 2].symbol;
1877 /* Check objfile where the variable itself is placed.
1878 SYMBOL_OBJ_SECTION (symbol) may be NULL. */
1879 if ((*objfile_func) (symbol_objfile (symbol), data))
1882 /* Check objfile where is placed the code touching the variable. */
1883 objfile = lookup_objfile_from_block (block);
1885 type = SYMBOL_TYPE (symbol);
1888 case OP_VAR_MSYM_VALUE:
1889 objfile = elts[pos + 1].objfile;
1893 /* Invoke callbacks for TYPE and OBJFILE if they were set as non-NULL. */
1895 if (type && TYPE_OBJFILE (type)
1896 && (*objfile_func) (TYPE_OBJFILE (type), data))
1898 if (objfile && (*objfile_func) (objfile, data))
1904 /* Call OBJFILE_FUNC for any objfile found being referenced by EXP.
1905 OBJFILE_FUNC is never called with NULL OBJFILE. OBJFILE_FUNC get
1906 passed an arbitrary caller supplied DATA pointer. If OBJFILE_FUNC
1907 returns non-zero value then (any other) non-zero value is immediately
1908 returned to the caller. Otherwise zero is returned after iterating
1909 through whole EXP. */
1912 exp_iterate (struct expression *exp,
1913 int (*objfile_func) (struct objfile *objfile, void *data),
1918 for (endpos = exp->nelts; endpos > 0; )
1920 int pos, args, oplen = 0;
1922 operator_length (exp, endpos, &oplen, &args);
1923 gdb_assert (oplen > 0);
1925 pos = endpos - oplen;
1926 if (exp->language_defn->la_exp_desc->operator_check (exp, pos,
1927 objfile_func, data))
1936 /* Helper for exp_uses_objfile. */
1939 exp_uses_objfile_iter (struct objfile *exp_objfile, void *objfile_voidp)
1941 struct objfile *objfile = (struct objfile *) objfile_voidp;
1943 if (exp_objfile->separate_debug_objfile_backlink)
1944 exp_objfile = exp_objfile->separate_debug_objfile_backlink;
1946 return exp_objfile == objfile;
1949 /* Return 1 if EXP uses OBJFILE (and will become dangling when OBJFILE
1950 is unloaded), otherwise return 0. OBJFILE must not be a separate debug info
1954 exp_uses_objfile (struct expression *exp, struct objfile *objfile)
1956 gdb_assert (objfile->separate_debug_objfile_backlink == NULL);
1958 return exp_iterate (exp, exp_uses_objfile_iter, objfile);
1961 /* See definition in parser-defs.h. */
1964 increase_expout_size (struct parser_state *ps, size_t lenelt)
1966 if ((ps->expout_ptr + lenelt) >= ps->expout_size)
1968 ps->expout_size = std::max (ps->expout_size * 2,
1969 ps->expout_ptr + lenelt + 10);
1970 ps->expout = (struct expression *)
1971 xrealloc (ps->expout, (sizeof (struct expression)
1972 + EXP_ELEM_TO_BYTES (ps->expout_size)));
1977 _initialize_parse (void)
1979 type_stack.size = 0;
1980 type_stack.depth = 0;
1981 type_stack.elements = NULL;
1983 add_setshow_zuinteger_cmd ("expression", class_maintenance,
1985 _("Set expression debugging."),
1986 _("Show expression debugging."),
1987 _("When non-zero, the internal representation "
1988 "of expressions will be printed."),
1990 show_expressiondebug,
1991 &setdebuglist, &showdebuglist);
1992 add_setshow_boolean_cmd ("parser", class_maintenance,
1994 _("Set parser debugging."),
1995 _("Show parser debugging."),
1996 _("When non-zero, expression parser "
1997 "tracing will be enabled."),
2000 &setdebuglist, &showdebuglist);