1 /* Parse expressions for GDB.
3 Copyright (C) 1986-2019 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 */
47 #include "target-float.h"
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 innermost_block_tracker 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 gdb::unique_xmalloc_ptr
<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 int prefixify_subexp (struct expression
*, struct expression
*, int,
117 static expression_up
parse_exp_in_context (const char **, CORE_ADDR
,
118 const struct block
*, int,
120 innermost_block_tracker_types
);
122 static void increase_expout_size (struct parser_state
*ps
, size_t lenelt
);
125 /* Documented at it's declaration. */
128 innermost_block_tracker::update (const struct block
*b
,
129 innermost_block_tracker_types t
)
131 if ((m_types
& t
) != 0
132 && (m_innermost_block
== NULL
133 || contained_in (b
, m_innermost_block
)))
134 m_innermost_block
= b
;
137 /* Data structure for saving values of arglist_len for function calls whose
138 arguments contain other function calls. */
140 static std::vector
<int> *funcall_chain
;
142 /* Begin counting arguments for a function call,
143 saving the data about any containing call. */
148 funcall_chain
->push_back (arglist_len
);
152 /* Return the number of arguments in a function call just terminated,
153 and restore the data for the containing function call. */
158 int val
= arglist_len
;
159 arglist_len
= funcall_chain
->back ();
160 funcall_chain
->pop_back ();
166 /* See definition in parser-defs.h. */
168 parser_state::parser_state (const struct language_defn
*lang
,
169 struct gdbarch
*gdbarch
)
171 expout (XNEWVAR (expression
,
173 + EXP_ELEM_TO_BYTES (expout_size
)))),
176 expout
->language_defn
= lang
;
177 expout
->gdbarch
= gdbarch
;
181 parser_state::release ()
183 /* Record the actual number of expression elements, and then
184 reallocate the expression memory so that we free up any
187 expout
->nelts
= expout_ptr
;
188 expout
.reset (XRESIZEVAR (expression
, expout
.release (),
190 + EXP_ELEM_TO_BYTES (expout_ptr
))));
192 return std::move (expout
);
195 /* This page contains the functions for adding data to the struct expression
196 being constructed. */
198 /* Add one element to the end of the expression. */
200 /* To avoid a bug in the Sun 4 compiler, we pass things that can fit into
201 a register through here. */
204 write_exp_elt (struct parser_state
*ps
, const union exp_element
*expelt
)
206 if (ps
->expout_ptr
>= ps
->expout_size
)
208 ps
->expout_size
*= 2;
209 ps
->expout
.reset (XRESIZEVAR (expression
, ps
->expout
.release (),
211 + EXP_ELEM_TO_BYTES (ps
->expout_size
))));
213 ps
->expout
->elts
[ps
->expout_ptr
++] = *expelt
;
217 write_exp_elt_opcode (struct parser_state
*ps
, enum exp_opcode expelt
)
219 union exp_element tmp
;
221 memset (&tmp
, 0, sizeof (union exp_element
));
223 write_exp_elt (ps
, &tmp
);
227 write_exp_elt_sym (struct parser_state
*ps
, struct symbol
*expelt
)
229 union exp_element tmp
;
231 memset (&tmp
, 0, sizeof (union exp_element
));
233 write_exp_elt (ps
, &tmp
);
237 write_exp_elt_msym (struct parser_state
*ps
, minimal_symbol
*expelt
)
239 union exp_element tmp
;
241 memset (&tmp
, 0, sizeof (union exp_element
));
242 tmp
.msymbol
= expelt
;
243 write_exp_elt (ps
, &tmp
);
247 write_exp_elt_block (struct parser_state
*ps
, const struct block
*b
)
249 union exp_element tmp
;
251 memset (&tmp
, 0, sizeof (union exp_element
));
253 write_exp_elt (ps
, &tmp
);
257 write_exp_elt_objfile (struct parser_state
*ps
, struct objfile
*objfile
)
259 union exp_element tmp
;
261 memset (&tmp
, 0, sizeof (union exp_element
));
262 tmp
.objfile
= objfile
;
263 write_exp_elt (ps
, &tmp
);
267 write_exp_elt_longcst (struct parser_state
*ps
, LONGEST expelt
)
269 union exp_element tmp
;
271 memset (&tmp
, 0, sizeof (union exp_element
));
272 tmp
.longconst
= expelt
;
273 write_exp_elt (ps
, &tmp
);
277 write_exp_elt_floatcst (struct parser_state
*ps
, const gdb_byte expelt
[16])
279 union exp_element tmp
;
282 for (index
= 0; index
< 16; index
++)
283 tmp
.floatconst
[index
] = expelt
[index
];
285 write_exp_elt (ps
, &tmp
);
289 write_exp_elt_type (struct parser_state
*ps
, struct type
*expelt
)
291 union exp_element tmp
;
293 memset (&tmp
, 0, sizeof (union exp_element
));
295 write_exp_elt (ps
, &tmp
);
299 write_exp_elt_intern (struct parser_state
*ps
, struct internalvar
*expelt
)
301 union exp_element tmp
;
303 memset (&tmp
, 0, sizeof (union exp_element
));
304 tmp
.internalvar
= expelt
;
305 write_exp_elt (ps
, &tmp
);
308 /* Add a string constant to the end of the expression.
310 String constants are stored by first writing an expression element
311 that contains the length of the string, then stuffing the string
312 constant itself into however many expression elements are needed
313 to hold it, and then writing another expression element that contains
314 the length of the string. I.e. an expression element at each end of
315 the string records the string length, so you can skip over the
316 expression elements containing the actual string bytes from either
317 end of the string. Note that this also allows gdb to handle
318 strings with embedded null bytes, as is required for some languages.
320 Don't be fooled by the fact that the string is null byte terminated,
321 this is strictly for the convenience of debugging gdb itself.
322 Gdb does not depend up the string being null terminated, since the
323 actual length is recorded in expression elements at each end of the
324 string. The null byte is taken into consideration when computing how
325 many expression elements are required to hold the string constant, of
330 write_exp_string (struct parser_state
*ps
, struct stoken str
)
332 int len
= str
.length
;
336 /* Compute the number of expression elements required to hold the string
337 (including a null byte terminator), along with one expression element
338 at each end to record the actual string length (not including the
339 null byte terminator). */
341 lenelt
= 2 + BYTES_TO_EXP_ELEM (len
+ 1);
343 increase_expout_size (ps
, lenelt
);
345 /* Write the leading length expression element (which advances the current
346 expression element index), then write the string constant followed by a
347 terminating null byte, and then write the trailing length expression
350 write_exp_elt_longcst (ps
, (LONGEST
) len
);
351 strdata
= (char *) &ps
->expout
->elts
[ps
->expout_ptr
];
352 memcpy (strdata
, str
.ptr
, len
);
353 *(strdata
+ len
) = '\0';
354 ps
->expout_ptr
+= lenelt
- 2;
355 write_exp_elt_longcst (ps
, (LONGEST
) len
);
358 /* Add a vector of string constants to the end of the expression.
360 This adds an OP_STRING operation, but encodes the contents
361 differently from write_exp_string. The language is expected to
362 handle evaluation of this expression itself.
364 After the usual OP_STRING header, TYPE is written into the
365 expression as a long constant. The interpretation of this field is
366 up to the language evaluator.
368 Next, each string in VEC is written. The length is written as a
369 long constant, followed by the contents of the string. */
372 write_exp_string_vector (struct parser_state
*ps
, int type
,
373 struct stoken_vector
*vec
)
378 /* Compute the size. We compute the size in number of slots to
379 avoid issues with string padding. */
381 for (i
= 0; i
< vec
->len
; ++i
)
383 /* One slot for the length of this element, plus the number of
384 slots needed for this string. */
385 n_slots
+= 1 + BYTES_TO_EXP_ELEM (vec
->tokens
[i
].length
);
388 /* One more slot for the type of the string. */
391 /* Now compute a phony string length. */
392 len
= EXP_ELEM_TO_BYTES (n_slots
) - 1;
395 increase_expout_size (ps
, n_slots
);
397 write_exp_elt_opcode (ps
, OP_STRING
);
398 write_exp_elt_longcst (ps
, len
);
399 write_exp_elt_longcst (ps
, type
);
401 for (i
= 0; i
< vec
->len
; ++i
)
403 write_exp_elt_longcst (ps
, vec
->tokens
[i
].length
);
404 memcpy (&ps
->expout
->elts
[ps
->expout_ptr
], vec
->tokens
[i
].ptr
,
405 vec
->tokens
[i
].length
);
406 ps
->expout_ptr
+= BYTES_TO_EXP_ELEM (vec
->tokens
[i
].length
);
409 write_exp_elt_longcst (ps
, len
);
410 write_exp_elt_opcode (ps
, OP_STRING
);
413 /* Add a bitstring constant to the end of the expression.
415 Bitstring constants are stored by first writing an expression element
416 that contains the length of the bitstring (in bits), then stuffing the
417 bitstring constant itself into however many expression elements are
418 needed to hold it, and then writing another expression element that
419 contains the length of the bitstring. I.e. an expression element at
420 each end of the bitstring records the bitstring length, so you can skip
421 over the expression elements containing the actual bitstring bytes from
422 either end of the bitstring. */
425 write_exp_bitstring (struct parser_state
*ps
, struct stoken str
)
427 int bits
= str
.length
; /* length in bits */
428 int len
= (bits
+ HOST_CHAR_BIT
- 1) / HOST_CHAR_BIT
;
432 /* Compute the number of expression elements required to hold the bitstring,
433 along with one expression element at each end to record the actual
434 bitstring length in bits. */
436 lenelt
= 2 + BYTES_TO_EXP_ELEM (len
);
438 increase_expout_size (ps
, lenelt
);
440 /* Write the leading length expression element (which advances the current
441 expression element index), then write the bitstring constant, and then
442 write the trailing length expression element. */
444 write_exp_elt_longcst (ps
, (LONGEST
) bits
);
445 strdata
= (char *) &ps
->expout
->elts
[ps
->expout_ptr
];
446 memcpy (strdata
, str
.ptr
, len
);
447 ps
->expout_ptr
+= lenelt
- 2;
448 write_exp_elt_longcst (ps
, (LONGEST
) bits
);
451 /* Return the type of MSYMBOL, a minimal symbol of OBJFILE. If
452 ADDRESS_P is not NULL, set it to the MSYMBOL's resolved
456 find_minsym_type_and_address (minimal_symbol
*msymbol
,
457 struct objfile
*objfile
,
458 CORE_ADDR
*address_p
)
460 bound_minimal_symbol bound_msym
= {msymbol
, objfile
};
461 struct obj_section
*section
= MSYMBOL_OBJ_SECTION (objfile
, msymbol
);
462 enum minimal_symbol_type type
= MSYMBOL_TYPE (msymbol
);
464 bool is_tls
= (section
!= NULL
465 && section
->the_bfd_section
->flags
& SEC_THREAD_LOCAL
);
467 /* The minimal symbol might point to a function descriptor;
468 resolve it to the actual code address instead. */
472 /* Addresses of TLS symbols are really offsets into a
473 per-objfile/per-thread storage block. */
474 addr
= MSYMBOL_VALUE_RAW_ADDRESS (bound_msym
.minsym
);
476 else if (msymbol_is_function (objfile
, msymbol
, &addr
))
478 if (addr
!= BMSYMBOL_VALUE_ADDRESS (bound_msym
))
480 /* This means we resolved a function descriptor, and we now
481 have an address for a code/text symbol instead of a data
483 if (MSYMBOL_TYPE (msymbol
) == mst_data_gnu_ifunc
)
484 type
= mst_text_gnu_ifunc
;
491 addr
= BMSYMBOL_VALUE_ADDRESS (bound_msym
);
493 if (overlay_debugging
)
494 addr
= symbol_overlayed_address (addr
, section
);
498 /* Skip translation if caller does not need the address. */
499 if (address_p
!= NULL
)
500 *address_p
= target_translate_tls_address (objfile
, addr
);
501 return objfile_type (objfile
)->nodebug_tls_symbol
;
504 if (address_p
!= NULL
)
511 case mst_solib_trampoline
:
512 return objfile_type (objfile
)->nodebug_text_symbol
;
514 case mst_text_gnu_ifunc
:
515 return objfile_type (objfile
)->nodebug_text_gnu_ifunc_symbol
;
521 return objfile_type (objfile
)->nodebug_data_symbol
;
523 case mst_slot_got_plt
:
524 return objfile_type (objfile
)->nodebug_got_plt_symbol
;
527 return objfile_type (objfile
)->nodebug_unknown_symbol
;
531 /* Add the appropriate elements for a minimal symbol to the end of
535 write_exp_msymbol (struct parser_state
*ps
,
536 struct bound_minimal_symbol bound_msym
)
538 write_exp_elt_opcode (ps
, OP_VAR_MSYM_VALUE
);
539 write_exp_elt_objfile (ps
, bound_msym
.objfile
);
540 write_exp_elt_msym (ps
, bound_msym
.minsym
);
541 write_exp_elt_opcode (ps
, OP_VAR_MSYM_VALUE
);
544 /* Mark the current index as the starting location of a structure
545 expression. This is used when completing on field names. */
548 mark_struct_expression (struct parser_state
*ps
)
550 gdb_assert (parse_completion
551 && expout_tag_completion_type
== TYPE_CODE_UNDEF
);
552 expout_last_struct
= ps
->expout_ptr
;
555 /* Indicate that the current parser invocation is completing a tag.
556 TAG is the type code of the tag, and PTR and LENGTH represent the
557 start of the tag name. */
560 mark_completion_tag (enum type_code tag
, const char *ptr
, int length
)
562 gdb_assert (parse_completion
563 && expout_tag_completion_type
== TYPE_CODE_UNDEF
564 && expout_completion_name
== NULL
565 && expout_last_struct
== -1);
566 gdb_assert (tag
== TYPE_CODE_UNION
567 || tag
== TYPE_CODE_STRUCT
568 || tag
== TYPE_CODE_ENUM
);
569 expout_tag_completion_type
= tag
;
570 expout_completion_name
.reset (xstrndup (ptr
, length
));
574 /* Recognize tokens that start with '$'. These include:
576 $regname A native register name or a "standard
579 $variable A convenience variable with a name chosen
582 $digits Value history with index <digits>, starting
583 from the first value which has index 1.
585 $$digits Value history with index <digits> relative
586 to the last value. I.e. $$0 is the last
587 value, $$1 is the one previous to that, $$2
588 is the one previous to $$1, etc.
590 $ | $0 | $$0 The last value in the value history.
592 $$ An abbreviation for the second to the last
593 value in the value history, I.e. $$1 */
596 write_dollar_variable (struct parser_state
*ps
, struct stoken str
)
598 struct block_symbol sym
;
599 struct bound_minimal_symbol msym
;
600 struct internalvar
*isym
= NULL
;
602 /* Handle the tokens $digits; also $ (short for $0) and $$ (short for $$1)
603 and $$digits (equivalent to $<-digits> if you could type that). */
607 /* Double dollar means negate the number and add -1 as well.
608 Thus $$ alone means -1. */
609 if (str
.length
>= 2 && str
.ptr
[1] == '$')
616 /* Just dollars (one or two). */
620 /* Is the rest of the token digits? */
621 for (; i
< str
.length
; i
++)
622 if (!(str
.ptr
[i
] >= '0' && str
.ptr
[i
] <= '9'))
626 i
= atoi (str
.ptr
+ 1 + negate
);
632 /* Handle tokens that refer to machine registers:
633 $ followed by a register name. */
634 i
= user_reg_map_name_to_regnum (ps
->gdbarch (),
635 str
.ptr
+ 1, str
.length
- 1);
637 goto handle_register
;
639 /* Any names starting with $ are probably debugger internal variables. */
641 isym
= lookup_only_internalvar (copy_name (str
) + 1);
644 write_exp_elt_opcode (ps
, OP_INTERNALVAR
);
645 write_exp_elt_intern (ps
, isym
);
646 write_exp_elt_opcode (ps
, OP_INTERNALVAR
);
650 /* On some systems, such as HP-UX and hppa-linux, certain system routines
651 have names beginning with $ or $$. Check for those, first. */
653 sym
= lookup_symbol (copy_name (str
), NULL
, VAR_DOMAIN
, NULL
);
656 write_exp_elt_opcode (ps
, OP_VAR_VALUE
);
657 write_exp_elt_block (ps
, sym
.block
);
658 write_exp_elt_sym (ps
, sym
.symbol
);
659 write_exp_elt_opcode (ps
, OP_VAR_VALUE
);
662 msym
= lookup_bound_minimal_symbol (copy_name (str
));
665 write_exp_msymbol (ps
, msym
);
669 /* Any other names are assumed to be debugger internal variables. */
671 write_exp_elt_opcode (ps
, OP_INTERNALVAR
);
672 write_exp_elt_intern (ps
, create_internalvar (copy_name (str
) + 1));
673 write_exp_elt_opcode (ps
, OP_INTERNALVAR
);
676 write_exp_elt_opcode (ps
, OP_LAST
);
677 write_exp_elt_longcst (ps
, (LONGEST
) i
);
678 write_exp_elt_opcode (ps
, OP_LAST
);
681 write_exp_elt_opcode (ps
, OP_REGISTER
);
684 write_exp_string (ps
, str
);
685 write_exp_elt_opcode (ps
, OP_REGISTER
);
686 innermost_block
.update (expression_context_block
,
687 INNERMOST_BLOCK_FOR_REGISTERS
);
693 find_template_name_end (const char *p
)
696 int just_seen_right
= 0;
697 int just_seen_colon
= 0;
698 int just_seen_space
= 0;
700 if (!p
|| (*p
!= '<'))
711 /* In future, may want to allow these?? */
714 depth
++; /* start nested template */
715 if (just_seen_colon
|| just_seen_right
|| just_seen_space
)
716 return 0; /* but not after : or :: or > or space */
719 if (just_seen_colon
|| just_seen_right
)
720 return 0; /* end a (nested?) template */
721 just_seen_right
= 1; /* but not after : or :: */
722 if (--depth
== 0) /* also disallow >>, insist on > > */
723 return ++p
; /* if outermost ended, return */
726 if (just_seen_space
|| (just_seen_colon
> 1))
727 return 0; /* nested class spec coming up */
728 just_seen_colon
++; /* we allow :: but not :::: */
733 if (!((*p
>= 'a' && *p
<= 'z') || /* allow token chars */
734 (*p
>= 'A' && *p
<= 'Z') ||
735 (*p
>= '0' && *p
<= '9') ||
736 (*p
== '_') || (*p
== ',') || /* commas for template args */
737 (*p
== '&') || (*p
== '*') || /* pointer and ref types */
738 (*p
== '(') || (*p
== ')') || /* function types */
739 (*p
== '[') || (*p
== ']'))) /* array types */
753 /* Return a null-terminated temporary copy of the name of a string token.
755 Tokens that refer to names do so with explicit pointer and length,
756 so they can share the storage that lexptr is parsing.
757 When it is necessary to pass a name to a function that expects
758 a null-terminated string, the substring is copied out
759 into a separate block of storage.
761 N.B. A single buffer is reused on each call. */
764 copy_name (struct stoken token
)
766 /* A temporary buffer for identifiers, so we can null-terminate them.
767 We allocate this with xrealloc. parse_exp_1 used to allocate with
768 alloca, using the size of the whole expression as a conservative
769 estimate of the space needed. However, macro expansion can
770 introduce names longer than the original expression; there's no
771 practical way to know beforehand how large that might be. */
772 static char *namecopy
;
773 static size_t namecopy_size
;
775 /* Make sure there's enough space for the token. */
776 if (namecopy_size
< token
.length
+ 1)
778 namecopy_size
= token
.length
+ 1;
779 namecopy
= (char *) xrealloc (namecopy
, token
.length
+ 1);
782 memcpy (namecopy
, token
.ptr
, token
.length
);
783 namecopy
[token
.length
] = 0;
789 /* See comments on parser-defs.h. */
792 prefixify_expression (struct expression
*expr
)
794 gdb_assert (expr
->nelts
> 0);
795 int len
= sizeof (struct expression
) + EXP_ELEM_TO_BYTES (expr
->nelts
);
796 struct expression
*temp
;
797 int inpos
= expr
->nelts
, outpos
= 0;
799 temp
= (struct expression
*) alloca (len
);
801 /* Copy the original expression into temp. */
802 memcpy (temp
, expr
, len
);
804 return prefixify_subexp (temp
, expr
, inpos
, outpos
);
807 /* Return the number of exp_elements in the postfix subexpression
808 of EXPR whose operator is at index ENDPOS - 1 in EXPR. */
811 length_of_subexp (struct expression
*expr
, int endpos
)
815 operator_length (expr
, endpos
, &oplen
, &args
);
819 oplen
+= length_of_subexp (expr
, endpos
- oplen
);
826 /* Sets *OPLENP to the length of the operator whose (last) index is
827 ENDPOS - 1 in EXPR, and sets *ARGSP to the number of arguments that
831 operator_length (const struct expression
*expr
, int endpos
, int *oplenp
,
834 expr
->language_defn
->la_exp_desc
->operator_length (expr
, endpos
,
838 /* Default value for operator_length in exp_descriptor vectors. */
841 operator_length_standard (const struct expression
*expr
, int endpos
,
842 int *oplenp
, int *argsp
)
846 enum range_type range_type
;
850 error (_("?error in operator_length_standard"));
852 i
= (int) expr
->elts
[endpos
- 1].opcode
;
858 oplen
= longest_to_int (expr
->elts
[endpos
- 2].longconst
);
859 oplen
= 5 + BYTES_TO_EXP_ELEM (oplen
+ 1);
865 case OP_VAR_MSYM_VALUE
:
869 case OP_FUNC_STATIC_VAR
:
870 oplen
= longest_to_int (expr
->elts
[endpos
- 2].longconst
);
871 oplen
= 4 + BYTES_TO_EXP_ELEM (oplen
+ 1);
879 case OP_VAR_ENTRY_VALUE
:
889 case OP_F77_UNDETERMINED_ARGLIST
:
891 args
= 1 + longest_to_int (expr
->elts
[endpos
- 2].longconst
);
895 oplen
= 5 + longest_to_int (expr
->elts
[endpos
- 2].longconst
);
899 case OP_OBJC_MSGCALL
: /* Objective C message (method) call. */
901 args
= 1 + longest_to_int (expr
->elts
[endpos
- 2].longconst
);
910 case UNOP_DYNAMIC_CAST
:
911 case UNOP_REINTERPRET_CAST
:
912 case UNOP_MEMVAL_TYPE
:
941 oplen
= longest_to_int (expr
->elts
[endpos
- 2].longconst
);
942 oplen
= 4 + BYTES_TO_EXP_ELEM (oplen
+ 1);
947 case STRUCTOP_STRUCT
:
954 case OP_OBJC_NSSTRING
: /* Objective C Foundation Class
955 NSString constant. */
956 case OP_OBJC_SELECTOR
: /* Objective C "@selector" pseudo-op. */
958 oplen
= longest_to_int (expr
->elts
[endpos
- 2].longconst
);
959 oplen
= 4 + BYTES_TO_EXP_ELEM (oplen
+ 1);
964 args
= longest_to_int (expr
->elts
[endpos
- 2].longconst
);
965 args
-= longest_to_int (expr
->elts
[endpos
- 3].longconst
);
975 case MULTI_SUBSCRIPT
:
977 args
= 1 + longest_to_int (expr
->elts
[endpos
- 2].longconst
);
980 case BINOP_ASSIGN_MODIFY
:
992 range_type
= (enum range_type
)
993 longest_to_int (expr
->elts
[endpos
- 2].longconst
);
997 case LOW_BOUND_DEFAULT
:
998 case LOW_BOUND_DEFAULT_EXCLUSIVE
:
999 case HIGH_BOUND_DEFAULT
:
1002 case BOTH_BOUND_DEFAULT
:
1005 case NONE_BOUND_DEFAULT
:
1006 case NONE_BOUND_DEFAULT_EXCLUSIVE
:
1014 args
= 1 + (i
< (int) BINOP_END
);
1021 /* Copy the subexpression ending just before index INEND in INEXPR
1022 into OUTEXPR, starting at index OUTBEG.
1023 In the process, convert it from suffix to prefix form.
1024 If EXPOUT_LAST_STRUCT is -1, then this function always returns -1.
1025 Otherwise, it returns the index of the subexpression which is the
1026 left-hand-side of the expression at EXPOUT_LAST_STRUCT. */
1029 prefixify_subexp (struct expression
*inexpr
,
1030 struct expression
*outexpr
, int inend
, int outbeg
)
1038 operator_length (inexpr
, inend
, &oplen
, &args
);
1040 /* Copy the final operator itself, from the end of the input
1041 to the beginning of the output. */
1043 memcpy (&outexpr
->elts
[outbeg
], &inexpr
->elts
[inend
],
1044 EXP_ELEM_TO_BYTES (oplen
));
1047 if (expout_last_struct
== inend
)
1048 result
= outbeg
- oplen
;
1050 /* Find the lengths of the arg subexpressions. */
1051 arglens
= (int *) alloca (args
* sizeof (int));
1052 for (i
= args
- 1; i
>= 0; i
--)
1054 oplen
= length_of_subexp (inexpr
, inend
);
1059 /* Now copy each subexpression, preserving the order of
1060 the subexpressions, but prefixifying each one.
1061 In this loop, inend starts at the beginning of
1062 the expression this level is working on
1063 and marches forward over the arguments.
1064 outbeg does similarly in the output. */
1065 for (i
= 0; i
< args
; i
++)
1071 r
= prefixify_subexp (inexpr
, outexpr
, inend
, outbeg
);
1074 /* Return immediately. We probably have only parsed a
1075 partial expression, so we don't want to try to reverse
1076 the other operands. */
1085 /* Read an expression from the string *STRINGPTR points to,
1086 parse it, and return a pointer to a struct expression that we malloc.
1087 Use block BLOCK as the lexical context for variable names;
1088 if BLOCK is zero, use the block of the selected stack frame.
1089 Meanwhile, advance *STRINGPTR to point after the expression,
1090 at the first nonwhite character that is not part of the expression
1091 (possibly a null character).
1093 If COMMA is nonzero, stop if a comma is reached. */
1096 parse_exp_1 (const char **stringptr
, CORE_ADDR pc
, const struct block
*block
,
1097 int comma
, innermost_block_tracker_types tracker_types
)
1099 return parse_exp_in_context (stringptr
, pc
, block
, comma
, 0, NULL
,
1103 /* As for parse_exp_1, except that if VOID_CONTEXT_P, then
1104 no value is expected from the expression.
1105 OUT_SUBEXP is set when attempting to complete a field name; in this
1106 case it is set to the index of the subexpression on the
1107 left-hand-side of the struct op. If not doing such completion, it
1108 is left untouched. */
1110 static expression_up
1111 parse_exp_in_context (const char **stringptr
, CORE_ADDR pc
,
1112 const struct block
*block
,
1113 int comma
, int void_context_p
, int *out_subexp
,
1114 innermost_block_tracker_types tracker_types
)
1116 const struct language_defn
*lang
= NULL
;
1119 lexptr
= *stringptr
;
1123 type_stack
.elements
.clear ();
1124 expout_last_struct
= -1;
1125 expout_tag_completion_type
= TYPE_CODE_UNDEF
;
1126 expout_completion_name
.reset ();
1127 innermost_block
.reset (tracker_types
);
1129 comma_terminates
= comma
;
1131 if (lexptr
== 0 || *lexptr
== 0)
1132 error_no_arg (_("expression to compute"));
1134 std::vector
<int> funcalls
;
1135 scoped_restore save_funcall_chain
= make_scoped_restore (&funcall_chain
,
1138 expression_context_block
= block
;
1140 /* If no context specified, try using the current frame, if any. */
1141 if (!expression_context_block
)
1142 expression_context_block
= get_selected_block (&expression_context_pc
);
1144 expression_context_pc
= BLOCK_ENTRY_PC (expression_context_block
);
1146 expression_context_pc
= pc
;
1148 /* Fall back to using the current source static context, if any. */
1150 if (!expression_context_block
)
1152 struct symtab_and_line cursal
= get_current_source_symtab_and_line ();
1154 expression_context_block
1155 = BLOCKVECTOR_BLOCK (SYMTAB_BLOCKVECTOR (cursal
.symtab
),
1157 if (expression_context_block
)
1158 expression_context_pc
= BLOCK_ENTRY_PC (expression_context_block
);
1161 if (language_mode
== language_mode_auto
&& block
!= NULL
)
1163 /* Find the language associated to the given context block.
1164 Default to the current language if it can not be determined.
1166 Note that using the language corresponding to the current frame
1167 can sometimes give unexpected results. For instance, this
1168 routine is often called several times during the inferior
1169 startup phase to re-parse breakpoint expressions after
1170 a new shared library has been loaded. The language associated
1171 to the current frame at this moment is not relevant for
1172 the breakpoint. Using it would therefore be silly, so it seems
1173 better to rely on the current language rather than relying on
1174 the current frame language to parse the expression. That's why
1175 we do the following language detection only if the context block
1176 has been specifically provided. */
1177 struct symbol
*func
= block_linkage_function (block
);
1180 lang
= language_def (SYMBOL_LANGUAGE (func
));
1181 if (lang
== NULL
|| lang
->la_language
== language_unknown
)
1182 lang
= current_language
;
1185 lang
= current_language
;
1187 /* get_current_arch may reset CURRENT_LANGUAGE via select_frame.
1188 While we need CURRENT_LANGUAGE to be set to LANG (for lookup_symbol
1189 and others called from *.y) ensure CURRENT_LANGUAGE gets restored
1190 to the value matching SELECTED_FRAME as set by get_current_arch. */
1192 parser_state
ps (lang
, get_current_arch ());
1194 scoped_restore_current_language lang_saver
;
1195 set_language (lang
->la_language
);
1199 lang
->la_parser (&ps
);
1201 CATCH (except
, RETURN_MASK_ALL
)
1203 /* If parsing for completion, allow this to succeed; but if no
1204 expression elements have been written, then there's nothing
1206 if (! parse_completion
|| ps
.expout_ptr
== 0)
1207 throw_exception (except
);
1211 /* We have to operate on an "expression *", due to la_post_parser,
1212 which explains this funny-looking double release. */
1213 expression_up result
= ps
.release ();
1215 /* Convert expression from postfix form as generated by yacc
1216 parser, to a prefix form. */
1218 if (expressiondebug
)
1219 dump_raw_expression (result
.get (), gdb_stdlog
,
1220 "before conversion to prefix form");
1222 subexp
= prefixify_expression (result
.get ());
1224 *out_subexp
= subexp
;
1226 lang
->la_post_parser (&result
, void_context_p
);
1228 if (expressiondebug
)
1229 dump_prefix_expression (result
.get (), gdb_stdlog
);
1231 *stringptr
= lexptr
;
1235 /* Parse STRING as an expression, and complain if this fails
1236 to use up all of the contents of STRING. */
1239 parse_expression (const char *string
)
1241 expression_up exp
= parse_exp_1 (&string
, 0, 0, 0);
1243 error (_("Junk after end of expression."));
1247 /* Same as parse_expression, but using the given language (LANG)
1248 to parse the expression. */
1251 parse_expression_with_language (const char *string
, enum language lang
)
1253 gdb::optional
<scoped_restore_current_language
> lang_saver
;
1254 if (current_language
->la_language
!= lang
)
1256 lang_saver
.emplace ();
1257 set_language (lang
);
1260 return parse_expression (string
);
1263 /* Parse STRING as an expression. If parsing ends in the middle of a
1264 field reference, return the type of the left-hand-side of the
1265 reference; furthermore, if the parsing ends in the field name,
1266 return the field name in *NAME. If the parsing ends in the middle
1267 of a field reference, but the reference is somehow invalid, throw
1268 an exception. In all other cases, return NULL. */
1271 parse_expression_for_completion (const char *string
,
1272 gdb::unique_xmalloc_ptr
<char> *name
,
1273 enum type_code
*code
)
1281 parse_completion
= 1;
1282 exp
= parse_exp_in_context (&string
, 0, 0, 0, 0, &subexp
,
1283 INNERMOST_BLOCK_FOR_SYMBOLS
);
1285 CATCH (except
, RETURN_MASK_ERROR
)
1287 /* Nothing, EXP remains NULL. */
1291 parse_completion
= 0;
1295 if (expout_tag_completion_type
!= TYPE_CODE_UNDEF
)
1297 *code
= expout_tag_completion_type
;
1298 *name
= std::move (expout_completion_name
);
1302 if (expout_last_struct
== -1)
1305 const char *fieldname
= extract_field_op (exp
.get (), &subexp
);
1306 if (fieldname
== NULL
)
1312 name
->reset (xstrdup (fieldname
));
1313 /* This might throw an exception. If so, we want to let it
1315 val
= evaluate_subexpression_type (exp
.get (), subexp
);
1317 return value_type (val
);
1320 /* A post-parser that does nothing. */
1323 null_post_parser (expression_up
*exp
, int void_context_p
)
1327 /* Parse floating point value P of length LEN.
1328 Return false if invalid, true if valid.
1329 The successfully parsed number is stored in DATA in
1330 target format for floating-point type TYPE.
1332 NOTE: This accepts the floating point syntax that sscanf accepts. */
1335 parse_float (const char *p
, int len
,
1336 const struct type
*type
, gdb_byte
*data
)
1338 return target_float_from_string (data
, type
, std::string (p
, len
));
1341 /* Stuff for maintaining a stack of types. Currently just used by C, but
1342 probably useful for any language which declares its types "backwards". */
1344 /* A helper function for insert_type and insert_type_address_space.
1345 This does work of expanding the type stack and inserting the new
1346 element, ELEMENT, into the stack at location SLOT. */
1349 insert_into_type_stack (int slot
, union type_stack_elt element
)
1351 gdb_assert (slot
<= type_stack
.elements
.size ());
1352 type_stack
.elements
.insert (type_stack
.elements
.begin () + slot
, element
);
1355 /* Insert a new type, TP, at the bottom of the type stack. If TP is
1356 tp_pointer, tp_reference or tp_rvalue_reference, it is inserted at the
1357 bottom. If TP is a qualifier, it is inserted at slot 1 (just above a
1358 previous tp_pointer) if there is anything on the stack, or simply pushed
1359 if the stack is empty. Other values for TP are invalid. */
1362 insert_type (enum type_pieces tp
)
1364 union type_stack_elt element
;
1367 gdb_assert (tp
== tp_pointer
|| tp
== tp_reference
1368 || tp
== tp_rvalue_reference
|| tp
== tp_const
1369 || tp
== tp_volatile
);
1371 /* If there is anything on the stack (we know it will be a
1372 tp_pointer), insert the qualifier above it. Otherwise, simply
1373 push this on the top of the stack. */
1374 if (!type_stack
.elements
.empty () && (tp
== tp_const
|| tp
== tp_volatile
))
1380 insert_into_type_stack (slot
, element
);
1384 push_type (enum type_pieces tp
)
1388 type_stack
.elements
.push_back (elt
);
1392 push_type_int (int n
)
1396 type_stack
.elements
.push_back (elt
);
1399 /* Insert a tp_space_identifier and the corresponding address space
1400 value into the stack. STRING is the name of an address space, as
1401 recognized by address_space_name_to_int. If the stack is empty,
1402 the new elements are simply pushed. If the stack is not empty,
1403 this function assumes that the first item on the stack is a
1404 tp_pointer, and the new values are inserted above the first
1408 insert_type_address_space (struct parser_state
*pstate
, char *string
)
1410 union type_stack_elt element
;
1413 /* If there is anything on the stack (we know it will be a
1414 tp_pointer), insert the address space qualifier above it.
1415 Otherwise, simply push this on the top of the stack. */
1416 if (!type_stack
.elements
.empty ())
1421 element
.piece
= tp_space_identifier
;
1422 insert_into_type_stack (slot
, element
);
1423 element
.int_val
= address_space_name_to_int (pstate
->gdbarch (),
1425 insert_into_type_stack (slot
, element
);
1431 if (!type_stack
.elements
.empty ())
1433 type_stack_elt elt
= type_stack
.elements
.back ();
1434 type_stack
.elements
.pop_back ();
1443 if (!type_stack
.elements
.empty ())
1445 type_stack_elt elt
= type_stack
.elements
.back ();
1446 type_stack
.elements
.pop_back ();
1449 /* "Can't happen". */
1453 /* Pop a type list element from the global type stack. */
1455 static std::vector
<struct type
*> *
1458 gdb_assert (!type_stack
.elements
.empty ());
1459 type_stack_elt elt
= type_stack
.elements
.back ();
1460 type_stack
.elements
.pop_back ();
1461 return elt
.typelist_val
;
1464 /* Pop a type_stack element from the global type stack. */
1466 static struct type_stack
*
1467 pop_type_stack (void)
1469 gdb_assert (!type_stack
.elements
.empty ());
1470 type_stack_elt elt
= type_stack
.elements
.back ();
1471 type_stack
.elements
.pop_back ();
1472 return elt
.stack_val
;
1475 /* Append the elements of the type stack FROM to the type stack TO.
1476 Always returns TO. */
1479 append_type_stack (struct type_stack
*to
, struct type_stack
*from
)
1481 to
->elements
.insert (to
->elements
.end (), from
->elements
.begin (),
1482 from
->elements
.end ());
1486 /* Push the type stack STACK as an element on the global type stack. */
1489 push_type_stack (struct type_stack
*stack
)
1492 elt
.stack_val
= stack
;
1493 type_stack
.elements
.push_back (elt
);
1494 push_type (tp_type_stack
);
1497 /* Copy the global type stack into a newly allocated type stack and
1498 return it. The global stack is cleared. The returned type stack
1499 must be freed with delete. */
1502 get_type_stack (void)
1504 struct type_stack
*result
= new struct type_stack (std::move (type_stack
));
1505 type_stack
.elements
.clear ();
1509 /* Push a function type with arguments onto the global type stack.
1510 LIST holds the argument types. If the final item in LIST is NULL,
1511 then the function will be varargs. */
1514 push_typelist (std::vector
<struct type
*> *list
)
1517 elt
.typelist_val
= list
;
1518 type_stack
.elements
.push_back (elt
);
1519 push_type (tp_function_with_arguments
);
1522 /* Pop the type stack and return a type_instance_flags that
1523 corresponds the const/volatile qualifiers on the stack. This is
1524 called by the C++ parser when parsing methods types, and as such no
1525 other kind of type in the type stack is expected. */
1528 follow_type_instance_flags ()
1530 type_instance_flags flags
= 0;
1533 switch (pop_type ())
1538 flags
|= TYPE_INSTANCE_FLAG_CONST
;
1541 flags
|= TYPE_INSTANCE_FLAG_VOLATILE
;
1544 gdb_assert_not_reached ("unrecognized tp_ value in follow_types");
1549 /* Pop the type stack and return the type which corresponds to FOLLOW_TYPE
1550 as modified by all the stuff on the stack. */
1552 follow_types (struct type
*follow_type
)
1556 int make_volatile
= 0;
1557 int make_addr_space
= 0;
1561 switch (pop_type ())
1566 follow_type
= make_cv_type (make_const
,
1567 TYPE_VOLATILE (follow_type
),
1570 follow_type
= make_cv_type (TYPE_CONST (follow_type
),
1573 if (make_addr_space
)
1574 follow_type
= make_type_with_address_space (follow_type
,
1576 make_const
= make_volatile
= 0;
1577 make_addr_space
= 0;
1585 case tp_space_identifier
:
1586 make_addr_space
= pop_type_int ();
1589 follow_type
= lookup_pointer_type (follow_type
);
1591 follow_type
= make_cv_type (make_const
,
1592 TYPE_VOLATILE (follow_type
),
1595 follow_type
= make_cv_type (TYPE_CONST (follow_type
),
1598 if (make_addr_space
)
1599 follow_type
= make_type_with_address_space (follow_type
,
1601 make_const
= make_volatile
= 0;
1602 make_addr_space
= 0;
1605 follow_type
= lookup_lvalue_reference_type (follow_type
);
1606 goto process_reference
;
1607 case tp_rvalue_reference
:
1608 follow_type
= lookup_rvalue_reference_type (follow_type
);
1611 follow_type
= make_cv_type (make_const
,
1612 TYPE_VOLATILE (follow_type
),
1615 follow_type
= make_cv_type (TYPE_CONST (follow_type
),
1618 if (make_addr_space
)
1619 follow_type
= make_type_with_address_space (follow_type
,
1621 make_const
= make_volatile
= 0;
1622 make_addr_space
= 0;
1625 array_size
= pop_type_int ();
1626 /* FIXME-type-allocation: need a way to free this type when we are
1629 lookup_array_range_type (follow_type
,
1630 0, array_size
>= 0 ? array_size
- 1 : 0);
1632 TYPE_HIGH_BOUND_KIND (TYPE_INDEX_TYPE (follow_type
))
1636 /* FIXME-type-allocation: need a way to free this type when we are
1638 follow_type
= lookup_function_type (follow_type
);
1641 case tp_function_with_arguments
:
1643 std::vector
<struct type
*> *args
= pop_typelist ();
1646 = lookup_function_type_with_arguments (follow_type
,
1654 struct type_stack
*stack
= pop_type_stack ();
1655 /* Sort of ugly, but not really much worse than the
1657 struct type_stack save
= type_stack
;
1659 type_stack
= *stack
;
1660 follow_type
= follow_types (follow_type
);
1661 gdb_assert (type_stack
.elements
.empty ());
1667 gdb_assert_not_reached ("unrecognized tp_ value in follow_types");
1672 /* This function avoids direct calls to fprintf
1673 in the parser generated debug code. */
1675 parser_fprintf (FILE *x
, const char *y
, ...)
1681 vfprintf_unfiltered (gdb_stderr
, y
, args
);
1684 fprintf_unfiltered (gdb_stderr
, " Unknown FILE used.\n");
1685 vfprintf_unfiltered (gdb_stderr
, y
, args
);
1690 /* Implementation of the exp_descriptor method operator_check. */
1693 operator_check_standard (struct expression
*exp
, int pos
,
1694 int (*objfile_func
) (struct objfile
*objfile
,
1698 const union exp_element
*const elts
= exp
->elts
;
1699 struct type
*type
= NULL
;
1700 struct objfile
*objfile
= NULL
;
1702 /* Extended operators should have been already handled by exp_descriptor
1703 iterate method of its specific language. */
1704 gdb_assert (elts
[pos
].opcode
< OP_EXTENDED0
);
1706 /* Track the callers of write_exp_elt_type for this table. */
1708 switch (elts
[pos
].opcode
)
1720 type
= elts
[pos
+ 1].type
;
1725 LONGEST arg
, nargs
= elts
[pos
+ 2].longconst
;
1727 for (arg
= 0; arg
< nargs
; arg
++)
1729 struct type
*inst_type
= elts
[pos
+ 3 + arg
].type
;
1730 struct objfile
*inst_objfile
= TYPE_OBJFILE (inst_type
);
1732 if (inst_objfile
&& (*objfile_func
) (inst_objfile
, data
))
1740 const struct block
*const block
= elts
[pos
+ 1].block
;
1741 const struct symbol
*const symbol
= elts
[pos
+ 2].symbol
;
1743 /* Check objfile where the variable itself is placed.
1744 SYMBOL_OBJ_SECTION (symbol) may be NULL. */
1745 if ((*objfile_func
) (symbol_objfile (symbol
), data
))
1748 /* Check objfile where is placed the code touching the variable. */
1749 objfile
= lookup_objfile_from_block (block
);
1751 type
= SYMBOL_TYPE (symbol
);
1754 case OP_VAR_MSYM_VALUE
:
1755 objfile
= elts
[pos
+ 1].objfile
;
1759 /* Invoke callbacks for TYPE and OBJFILE if they were set as non-NULL. */
1761 if (type
&& TYPE_OBJFILE (type
)
1762 && (*objfile_func
) (TYPE_OBJFILE (type
), data
))
1764 if (objfile
&& (*objfile_func
) (objfile
, data
))
1770 /* Call OBJFILE_FUNC for any objfile found being referenced by EXP.
1771 OBJFILE_FUNC is never called with NULL OBJFILE. OBJFILE_FUNC get
1772 passed an arbitrary caller supplied DATA pointer. If OBJFILE_FUNC
1773 returns non-zero value then (any other) non-zero value is immediately
1774 returned to the caller. Otherwise zero is returned after iterating
1775 through whole EXP. */
1778 exp_iterate (struct expression
*exp
,
1779 int (*objfile_func
) (struct objfile
*objfile
, void *data
),
1784 for (endpos
= exp
->nelts
; endpos
> 0; )
1786 int pos
, args
, oplen
= 0;
1788 operator_length (exp
, endpos
, &oplen
, &args
);
1789 gdb_assert (oplen
> 0);
1791 pos
= endpos
- oplen
;
1792 if (exp
->language_defn
->la_exp_desc
->operator_check (exp
, pos
,
1793 objfile_func
, data
))
1802 /* Helper for exp_uses_objfile. */
1805 exp_uses_objfile_iter (struct objfile
*exp_objfile
, void *objfile_voidp
)
1807 struct objfile
*objfile
= (struct objfile
*) objfile_voidp
;
1809 if (exp_objfile
->separate_debug_objfile_backlink
)
1810 exp_objfile
= exp_objfile
->separate_debug_objfile_backlink
;
1812 return exp_objfile
== objfile
;
1815 /* Return 1 if EXP uses OBJFILE (and will become dangling when OBJFILE
1816 is unloaded), otherwise return 0. OBJFILE must not be a separate debug info
1820 exp_uses_objfile (struct expression
*exp
, struct objfile
*objfile
)
1822 gdb_assert (objfile
->separate_debug_objfile_backlink
== NULL
);
1824 return exp_iterate (exp
, exp_uses_objfile_iter
, objfile
);
1827 /* Reallocate the `expout' pointer inside PS so that it can accommodate
1828 at least LENELT expression elements. This function does nothing if
1829 there is enough room for the elements. */
1832 increase_expout_size (struct parser_state
*ps
, size_t lenelt
)
1834 if ((ps
->expout_ptr
+ lenelt
) >= ps
->expout_size
)
1836 ps
->expout_size
= std::max (ps
->expout_size
* 2,
1837 ps
->expout_ptr
+ lenelt
+ 10);
1838 ps
->expout
.reset (XRESIZEVAR (expression
,
1839 ps
->expout
.release (),
1840 (sizeof (struct expression
)
1841 + EXP_ELEM_TO_BYTES (ps
->expout_size
))));
1846 _initialize_parse (void)
1848 add_setshow_zuinteger_cmd ("expression", class_maintenance
,
1850 _("Set expression debugging."),
1851 _("Show expression debugging."),
1852 _("When non-zero, the internal representation "
1853 "of expressions will be printed."),
1855 show_expressiondebug
,
1856 &setdebuglist
, &showdebuglist
);
1857 add_setshow_boolean_cmd ("parser", class_maintenance
,
1859 _("Set parser debugging."),
1860 _("Show parser debugging."),
1861 _("When non-zero, expression parser "
1862 "tracing will be enabled."),
1865 &setdebuglist
, &showdebuglist
);