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 innermost_block_tracker innermost_block
;
71 static struct type_stack type_stack
;
73 const char *prev_lexptr
;
75 /* True if parsing an expression to attempt completion. */
78 /* The index of the last struct expression directly before a '.' or
79 '->'. This is set when parsing and is only used when completing a
80 field name. It is -1 if no dereference operation was found. */
81 static int expout_last_struct
= -1;
83 /* If we are completing a tagged type name, this will be nonzero. */
84 static enum type_code expout_tag_completion_type
= TYPE_CODE_UNDEF
;
86 /* The token for tagged type name completion. */
87 static gdb::unique_xmalloc_ptr
<char> expout_completion_name
;
90 static unsigned int expressiondebug
= 0;
92 show_expressiondebug (struct ui_file
*file
, int from_tty
,
93 struct cmd_list_element
*c
, const char *value
)
95 fprintf_filtered (file
, _("Expression debugging is %s.\n"), value
);
99 /* Non-zero if an expression parser should set yydebug. */
103 show_parserdebug (struct ui_file
*file
, int from_tty
,
104 struct cmd_list_element
*c
, const char *value
)
106 fprintf_filtered (file
, _("Parser debugging is %s.\n"), value
);
110 static int prefixify_subexp (struct expression
*, struct expression
*, int,
113 static expression_up
parse_exp_in_context (const char **, CORE_ADDR
,
114 const struct block
*, int,
116 innermost_block_tracker_types
);
118 static void increase_expout_size (struct expr_builder
*ps
, size_t lenelt
);
121 /* Documented at it's declaration. */
124 innermost_block_tracker::update (const struct block
*b
,
125 innermost_block_tracker_types t
)
127 if ((m_types
& t
) != 0
128 && (m_innermost_block
== NULL
129 || contained_in (b
, m_innermost_block
)))
130 m_innermost_block
= b
;
133 /* Data structure for saving values of arglist_len for function calls whose
134 arguments contain other function calls. */
136 static std::vector
<int> *funcall_chain
;
138 /* Begin counting arguments for a function call,
139 saving the data about any containing call. */
144 funcall_chain
->push_back (arglist_len
);
148 /* Return the number of arguments in a function call just terminated,
149 and restore the data for the containing function call. */
154 int val
= arglist_len
;
155 arglist_len
= funcall_chain
->back ();
156 funcall_chain
->pop_back ();
162 /* See definition in parser-defs.h. */
164 expr_builder::expr_builder (const struct language_defn
*lang
,
165 struct gdbarch
*gdbarch
)
167 expout (XNEWVAR (expression
,
169 + EXP_ELEM_TO_BYTES (expout_size
)))),
172 expout
->language_defn
= lang
;
173 expout
->gdbarch
= gdbarch
;
177 expr_builder::release ()
179 /* Record the actual number of expression elements, and then
180 reallocate the expression memory so that we free up any
183 expout
->nelts
= expout_ptr
;
184 expout
.reset (XRESIZEVAR (expression
, expout
.release (),
186 + EXP_ELEM_TO_BYTES (expout_ptr
))));
188 return std::move (expout
);
191 /* This page contains the functions for adding data to the struct expression
192 being constructed. */
194 /* Add one element to the end of the expression. */
196 /* To avoid a bug in the Sun 4 compiler, we pass things that can fit into
197 a register through here. */
200 write_exp_elt (struct expr_builder
*ps
, const union exp_element
*expelt
)
202 if (ps
->expout_ptr
>= ps
->expout_size
)
204 ps
->expout_size
*= 2;
205 ps
->expout
.reset (XRESIZEVAR (expression
, ps
->expout
.release (),
207 + EXP_ELEM_TO_BYTES (ps
->expout_size
))));
209 ps
->expout
->elts
[ps
->expout_ptr
++] = *expelt
;
213 write_exp_elt_opcode (struct expr_builder
*ps
, enum exp_opcode expelt
)
215 union exp_element tmp
;
217 memset (&tmp
, 0, sizeof (union exp_element
));
219 write_exp_elt (ps
, &tmp
);
223 write_exp_elt_sym (struct expr_builder
*ps
, struct symbol
*expelt
)
225 union exp_element tmp
;
227 memset (&tmp
, 0, sizeof (union exp_element
));
229 write_exp_elt (ps
, &tmp
);
233 write_exp_elt_msym (struct expr_builder
*ps
, minimal_symbol
*expelt
)
235 union exp_element tmp
;
237 memset (&tmp
, 0, sizeof (union exp_element
));
238 tmp
.msymbol
= expelt
;
239 write_exp_elt (ps
, &tmp
);
243 write_exp_elt_block (struct expr_builder
*ps
, const struct block
*b
)
245 union exp_element tmp
;
247 memset (&tmp
, 0, sizeof (union exp_element
));
249 write_exp_elt (ps
, &tmp
);
253 write_exp_elt_objfile (struct expr_builder
*ps
, struct objfile
*objfile
)
255 union exp_element tmp
;
257 memset (&tmp
, 0, sizeof (union exp_element
));
258 tmp
.objfile
= objfile
;
259 write_exp_elt (ps
, &tmp
);
263 write_exp_elt_longcst (struct expr_builder
*ps
, LONGEST expelt
)
265 union exp_element tmp
;
267 memset (&tmp
, 0, sizeof (union exp_element
));
268 tmp
.longconst
= expelt
;
269 write_exp_elt (ps
, &tmp
);
273 write_exp_elt_floatcst (struct expr_builder
*ps
, const gdb_byte expelt
[16])
275 union exp_element tmp
;
278 for (index
= 0; index
< 16; index
++)
279 tmp
.floatconst
[index
] = expelt
[index
];
281 write_exp_elt (ps
, &tmp
);
285 write_exp_elt_type (struct expr_builder
*ps
, struct type
*expelt
)
287 union exp_element tmp
;
289 memset (&tmp
, 0, sizeof (union exp_element
));
291 write_exp_elt (ps
, &tmp
);
295 write_exp_elt_intern (struct expr_builder
*ps
, struct internalvar
*expelt
)
297 union exp_element tmp
;
299 memset (&tmp
, 0, sizeof (union exp_element
));
300 tmp
.internalvar
= expelt
;
301 write_exp_elt (ps
, &tmp
);
304 /* Add a string constant to the end of the expression.
306 String constants are stored by first writing an expression element
307 that contains the length of the string, then stuffing the string
308 constant itself into however many expression elements are needed
309 to hold it, and then writing another expression element that contains
310 the length of the string. I.e. an expression element at each end of
311 the string records the string length, so you can skip over the
312 expression elements containing the actual string bytes from either
313 end of the string. Note that this also allows gdb to handle
314 strings with embedded null bytes, as is required for some languages.
316 Don't be fooled by the fact that the string is null byte terminated,
317 this is strictly for the convenience of debugging gdb itself.
318 Gdb does not depend up the string being null terminated, since the
319 actual length is recorded in expression elements at each end of the
320 string. The null byte is taken into consideration when computing how
321 many expression elements are required to hold the string constant, of
326 write_exp_string (struct expr_builder
*ps
, struct stoken str
)
328 int len
= str
.length
;
332 /* Compute the number of expression elements required to hold the string
333 (including a null byte terminator), along with one expression element
334 at each end to record the actual string length (not including the
335 null byte terminator). */
337 lenelt
= 2 + BYTES_TO_EXP_ELEM (len
+ 1);
339 increase_expout_size (ps
, lenelt
);
341 /* Write the leading length expression element (which advances the current
342 expression element index), then write the string constant followed by a
343 terminating null byte, and then write the trailing length expression
346 write_exp_elt_longcst (ps
, (LONGEST
) len
);
347 strdata
= (char *) &ps
->expout
->elts
[ps
->expout_ptr
];
348 memcpy (strdata
, str
.ptr
, len
);
349 *(strdata
+ len
) = '\0';
350 ps
->expout_ptr
+= lenelt
- 2;
351 write_exp_elt_longcst (ps
, (LONGEST
) len
);
354 /* Add a vector of string constants to the end of the expression.
356 This adds an OP_STRING operation, but encodes the contents
357 differently from write_exp_string. The language is expected to
358 handle evaluation of this expression itself.
360 After the usual OP_STRING header, TYPE is written into the
361 expression as a long constant. The interpretation of this field is
362 up to the language evaluator.
364 Next, each string in VEC is written. The length is written as a
365 long constant, followed by the contents of the string. */
368 write_exp_string_vector (struct expr_builder
*ps
, int type
,
369 struct stoken_vector
*vec
)
374 /* Compute the size. We compute the size in number of slots to
375 avoid issues with string padding. */
377 for (i
= 0; i
< vec
->len
; ++i
)
379 /* One slot for the length of this element, plus the number of
380 slots needed for this string. */
381 n_slots
+= 1 + BYTES_TO_EXP_ELEM (vec
->tokens
[i
].length
);
384 /* One more slot for the type of the string. */
387 /* Now compute a phony string length. */
388 len
= EXP_ELEM_TO_BYTES (n_slots
) - 1;
391 increase_expout_size (ps
, n_slots
);
393 write_exp_elt_opcode (ps
, OP_STRING
);
394 write_exp_elt_longcst (ps
, len
);
395 write_exp_elt_longcst (ps
, type
);
397 for (i
= 0; i
< vec
->len
; ++i
)
399 write_exp_elt_longcst (ps
, vec
->tokens
[i
].length
);
400 memcpy (&ps
->expout
->elts
[ps
->expout_ptr
], vec
->tokens
[i
].ptr
,
401 vec
->tokens
[i
].length
);
402 ps
->expout_ptr
+= BYTES_TO_EXP_ELEM (vec
->tokens
[i
].length
);
405 write_exp_elt_longcst (ps
, len
);
406 write_exp_elt_opcode (ps
, OP_STRING
);
409 /* Add a bitstring constant to the end of the expression.
411 Bitstring constants are stored by first writing an expression element
412 that contains the length of the bitstring (in bits), then stuffing the
413 bitstring constant itself into however many expression elements are
414 needed to hold it, and then writing another expression element that
415 contains the length of the bitstring. I.e. an expression element at
416 each end of the bitstring records the bitstring length, so you can skip
417 over the expression elements containing the actual bitstring bytes from
418 either end of the bitstring. */
421 write_exp_bitstring (struct expr_builder
*ps
, struct stoken str
)
423 int bits
= str
.length
; /* length in bits */
424 int len
= (bits
+ HOST_CHAR_BIT
- 1) / HOST_CHAR_BIT
;
428 /* Compute the number of expression elements required to hold the bitstring,
429 along with one expression element at each end to record the actual
430 bitstring length in bits. */
432 lenelt
= 2 + BYTES_TO_EXP_ELEM (len
);
434 increase_expout_size (ps
, lenelt
);
436 /* Write the leading length expression element (which advances the current
437 expression element index), then write the bitstring constant, and then
438 write the trailing length expression element. */
440 write_exp_elt_longcst (ps
, (LONGEST
) bits
);
441 strdata
= (char *) &ps
->expout
->elts
[ps
->expout_ptr
];
442 memcpy (strdata
, str
.ptr
, len
);
443 ps
->expout_ptr
+= lenelt
- 2;
444 write_exp_elt_longcst (ps
, (LONGEST
) bits
);
447 /* Return the type of MSYMBOL, a minimal symbol of OBJFILE. If
448 ADDRESS_P is not NULL, set it to the MSYMBOL's resolved
452 find_minsym_type_and_address (minimal_symbol
*msymbol
,
453 struct objfile
*objfile
,
454 CORE_ADDR
*address_p
)
456 bound_minimal_symbol bound_msym
= {msymbol
, objfile
};
457 struct obj_section
*section
= MSYMBOL_OBJ_SECTION (objfile
, msymbol
);
458 enum minimal_symbol_type type
= MSYMBOL_TYPE (msymbol
);
460 bool is_tls
= (section
!= NULL
461 && section
->the_bfd_section
->flags
& SEC_THREAD_LOCAL
);
463 /* The minimal symbol might point to a function descriptor;
464 resolve it to the actual code address instead. */
468 /* Addresses of TLS symbols are really offsets into a
469 per-objfile/per-thread storage block. */
470 addr
= MSYMBOL_VALUE_RAW_ADDRESS (bound_msym
.minsym
);
472 else if (msymbol_is_function (objfile
, msymbol
, &addr
))
474 if (addr
!= BMSYMBOL_VALUE_ADDRESS (bound_msym
))
476 /* This means we resolved a function descriptor, and we now
477 have an address for a code/text symbol instead of a data
479 if (MSYMBOL_TYPE (msymbol
) == mst_data_gnu_ifunc
)
480 type
= mst_text_gnu_ifunc
;
487 addr
= BMSYMBOL_VALUE_ADDRESS (bound_msym
);
489 if (overlay_debugging
)
490 addr
= symbol_overlayed_address (addr
, section
);
494 /* Skip translation if caller does not need the address. */
495 if (address_p
!= NULL
)
496 *address_p
= target_translate_tls_address (objfile
, addr
);
497 return objfile_type (objfile
)->nodebug_tls_symbol
;
500 if (address_p
!= NULL
)
507 case mst_solib_trampoline
:
508 return objfile_type (objfile
)->nodebug_text_symbol
;
510 case mst_text_gnu_ifunc
:
511 return objfile_type (objfile
)->nodebug_text_gnu_ifunc_symbol
;
517 return objfile_type (objfile
)->nodebug_data_symbol
;
519 case mst_slot_got_plt
:
520 return objfile_type (objfile
)->nodebug_got_plt_symbol
;
523 return objfile_type (objfile
)->nodebug_unknown_symbol
;
527 /* Add the appropriate elements for a minimal symbol to the end of
531 write_exp_msymbol (struct expr_builder
*ps
,
532 struct bound_minimal_symbol bound_msym
)
534 write_exp_elt_opcode (ps
, OP_VAR_MSYM_VALUE
);
535 write_exp_elt_objfile (ps
, bound_msym
.objfile
);
536 write_exp_elt_msym (ps
, bound_msym
.minsym
);
537 write_exp_elt_opcode (ps
, OP_VAR_MSYM_VALUE
);
540 /* Mark the current index as the starting location of a structure
541 expression. This is used when completing on field names. */
544 mark_struct_expression (struct expr_builder
*ps
)
546 gdb_assert (parse_completion
547 && expout_tag_completion_type
== TYPE_CODE_UNDEF
);
548 expout_last_struct
= ps
->expout_ptr
;
551 /* Indicate that the current parser invocation is completing a tag.
552 TAG is the type code of the tag, and PTR and LENGTH represent the
553 start of the tag name. */
556 mark_completion_tag (enum type_code tag
, const char *ptr
, int length
)
558 gdb_assert (parse_completion
559 && expout_tag_completion_type
== TYPE_CODE_UNDEF
560 && expout_completion_name
== NULL
561 && expout_last_struct
== -1);
562 gdb_assert (tag
== TYPE_CODE_UNION
563 || tag
== TYPE_CODE_STRUCT
564 || tag
== TYPE_CODE_ENUM
);
565 expout_tag_completion_type
= tag
;
566 expout_completion_name
.reset (xstrndup (ptr
, length
));
570 /* Recognize tokens that start with '$'. These include:
572 $regname A native register name or a "standard
575 $variable A convenience variable with a name chosen
578 $digits Value history with index <digits>, starting
579 from the first value which has index 1.
581 $$digits Value history with index <digits> relative
582 to the last value. I.e. $$0 is the last
583 value, $$1 is the one previous to that, $$2
584 is the one previous to $$1, etc.
586 $ | $0 | $$0 The last value in the value history.
588 $$ An abbreviation for the second to the last
589 value in the value history, I.e. $$1 */
592 write_dollar_variable (struct parser_state
*ps
, struct stoken str
)
594 struct block_symbol sym
;
595 struct bound_minimal_symbol msym
;
596 struct internalvar
*isym
= NULL
;
598 /* Handle the tokens $digits; also $ (short for $0) and $$ (short for $$1)
599 and $$digits (equivalent to $<-digits> if you could type that). */
603 /* Double dollar means negate the number and add -1 as well.
604 Thus $$ alone means -1. */
605 if (str
.length
>= 2 && str
.ptr
[1] == '$')
612 /* Just dollars (one or two). */
616 /* Is the rest of the token digits? */
617 for (; i
< str
.length
; i
++)
618 if (!(str
.ptr
[i
] >= '0' && str
.ptr
[i
] <= '9'))
622 i
= atoi (str
.ptr
+ 1 + negate
);
628 /* Handle tokens that refer to machine registers:
629 $ followed by a register name. */
630 i
= user_reg_map_name_to_regnum (ps
->gdbarch (),
631 str
.ptr
+ 1, str
.length
- 1);
633 goto handle_register
;
635 /* Any names starting with $ are probably debugger internal variables. */
637 isym
= lookup_only_internalvar (copy_name (str
) + 1);
640 write_exp_elt_opcode (ps
, OP_INTERNALVAR
);
641 write_exp_elt_intern (ps
, isym
);
642 write_exp_elt_opcode (ps
, OP_INTERNALVAR
);
646 /* On some systems, such as HP-UX and hppa-linux, certain system routines
647 have names beginning with $ or $$. Check for those, first. */
649 sym
= lookup_symbol (copy_name (str
), NULL
, VAR_DOMAIN
, NULL
);
652 write_exp_elt_opcode (ps
, OP_VAR_VALUE
);
653 write_exp_elt_block (ps
, sym
.block
);
654 write_exp_elt_sym (ps
, sym
.symbol
);
655 write_exp_elt_opcode (ps
, OP_VAR_VALUE
);
658 msym
= lookup_bound_minimal_symbol (copy_name (str
));
661 write_exp_msymbol (ps
, msym
);
665 /* Any other names are assumed to be debugger internal variables. */
667 write_exp_elt_opcode (ps
, OP_INTERNALVAR
);
668 write_exp_elt_intern (ps
, create_internalvar (copy_name (str
) + 1));
669 write_exp_elt_opcode (ps
, OP_INTERNALVAR
);
672 write_exp_elt_opcode (ps
, OP_LAST
);
673 write_exp_elt_longcst (ps
, (LONGEST
) i
);
674 write_exp_elt_opcode (ps
, OP_LAST
);
677 write_exp_elt_opcode (ps
, OP_REGISTER
);
680 write_exp_string (ps
, str
);
681 write_exp_elt_opcode (ps
, OP_REGISTER
);
682 innermost_block
.update (ps
->expression_context_block
,
683 INNERMOST_BLOCK_FOR_REGISTERS
);
689 find_template_name_end (const char *p
)
692 int just_seen_right
= 0;
693 int just_seen_colon
= 0;
694 int just_seen_space
= 0;
696 if (!p
|| (*p
!= '<'))
707 /* In future, may want to allow these?? */
710 depth
++; /* start nested template */
711 if (just_seen_colon
|| just_seen_right
|| just_seen_space
)
712 return 0; /* but not after : or :: or > or space */
715 if (just_seen_colon
|| just_seen_right
)
716 return 0; /* end a (nested?) template */
717 just_seen_right
= 1; /* but not after : or :: */
718 if (--depth
== 0) /* also disallow >>, insist on > > */
719 return ++p
; /* if outermost ended, return */
722 if (just_seen_space
|| (just_seen_colon
> 1))
723 return 0; /* nested class spec coming up */
724 just_seen_colon
++; /* we allow :: but not :::: */
729 if (!((*p
>= 'a' && *p
<= 'z') || /* allow token chars */
730 (*p
>= 'A' && *p
<= 'Z') ||
731 (*p
>= '0' && *p
<= '9') ||
732 (*p
== '_') || (*p
== ',') || /* commas for template args */
733 (*p
== '&') || (*p
== '*') || /* pointer and ref types */
734 (*p
== '(') || (*p
== ')') || /* function types */
735 (*p
== '[') || (*p
== ']'))) /* array types */
749 /* Return a null-terminated temporary copy of the name of a string token.
751 Tokens that refer to names do so with explicit pointer and length,
752 so they can share the storage that lexptr is parsing.
753 When it is necessary to pass a name to a function that expects
754 a null-terminated string, the substring is copied out
755 into a separate block of storage.
757 N.B. A single buffer is reused on each call. */
760 copy_name (struct stoken token
)
762 /* A temporary buffer for identifiers, so we can null-terminate them.
763 We allocate this with xrealloc. parse_exp_1 used to allocate with
764 alloca, using the size of the whole expression as a conservative
765 estimate of the space needed. However, macro expansion can
766 introduce names longer than the original expression; there's no
767 practical way to know beforehand how large that might be. */
768 static char *namecopy
;
769 static size_t namecopy_size
;
771 /* Make sure there's enough space for the token. */
772 if (namecopy_size
< token
.length
+ 1)
774 namecopy_size
= token
.length
+ 1;
775 namecopy
= (char *) xrealloc (namecopy
, token
.length
+ 1);
778 memcpy (namecopy
, token
.ptr
, token
.length
);
779 namecopy
[token
.length
] = 0;
785 /* See comments on parser-defs.h. */
788 prefixify_expression (struct expression
*expr
)
790 gdb_assert (expr
->nelts
> 0);
791 int len
= sizeof (struct expression
) + EXP_ELEM_TO_BYTES (expr
->nelts
);
792 struct expression
*temp
;
793 int inpos
= expr
->nelts
, outpos
= 0;
795 temp
= (struct expression
*) alloca (len
);
797 /* Copy the original expression into temp. */
798 memcpy (temp
, expr
, len
);
800 return prefixify_subexp (temp
, expr
, inpos
, outpos
);
803 /* Return the number of exp_elements in the postfix subexpression
804 of EXPR whose operator is at index ENDPOS - 1 in EXPR. */
807 length_of_subexp (struct expression
*expr
, int endpos
)
811 operator_length (expr
, endpos
, &oplen
, &args
);
815 oplen
+= length_of_subexp (expr
, endpos
- oplen
);
822 /* Sets *OPLENP to the length of the operator whose (last) index is
823 ENDPOS - 1 in EXPR, and sets *ARGSP to the number of arguments that
827 operator_length (const struct expression
*expr
, int endpos
, int *oplenp
,
830 expr
->language_defn
->la_exp_desc
->operator_length (expr
, endpos
,
834 /* Default value for operator_length in exp_descriptor vectors. */
837 operator_length_standard (const struct expression
*expr
, int endpos
,
838 int *oplenp
, int *argsp
)
842 enum range_type range_type
;
846 error (_("?error in operator_length_standard"));
848 i
= (int) expr
->elts
[endpos
- 1].opcode
;
854 oplen
= longest_to_int (expr
->elts
[endpos
- 2].longconst
);
855 oplen
= 5 + BYTES_TO_EXP_ELEM (oplen
+ 1);
861 case OP_VAR_MSYM_VALUE
:
865 case OP_FUNC_STATIC_VAR
:
866 oplen
= longest_to_int (expr
->elts
[endpos
- 2].longconst
);
867 oplen
= 4 + BYTES_TO_EXP_ELEM (oplen
+ 1);
875 case OP_VAR_ENTRY_VALUE
:
885 case OP_F77_UNDETERMINED_ARGLIST
:
887 args
= 1 + longest_to_int (expr
->elts
[endpos
- 2].longconst
);
891 oplen
= 5 + longest_to_int (expr
->elts
[endpos
- 2].longconst
);
895 case OP_OBJC_MSGCALL
: /* Objective C message (method) call. */
897 args
= 1 + longest_to_int (expr
->elts
[endpos
- 2].longconst
);
906 case UNOP_DYNAMIC_CAST
:
907 case UNOP_REINTERPRET_CAST
:
908 case UNOP_MEMVAL_TYPE
:
937 oplen
= longest_to_int (expr
->elts
[endpos
- 2].longconst
);
938 oplen
= 4 + BYTES_TO_EXP_ELEM (oplen
+ 1);
943 case STRUCTOP_STRUCT
:
950 case OP_OBJC_NSSTRING
: /* Objective C Foundation Class
951 NSString constant. */
952 case OP_OBJC_SELECTOR
: /* Objective C "@selector" pseudo-op. */
954 oplen
= longest_to_int (expr
->elts
[endpos
- 2].longconst
);
955 oplen
= 4 + BYTES_TO_EXP_ELEM (oplen
+ 1);
960 args
= longest_to_int (expr
->elts
[endpos
- 2].longconst
);
961 args
-= longest_to_int (expr
->elts
[endpos
- 3].longconst
);
971 case MULTI_SUBSCRIPT
:
973 args
= 1 + longest_to_int (expr
->elts
[endpos
- 2].longconst
);
976 case BINOP_ASSIGN_MODIFY
:
988 range_type
= (enum range_type
)
989 longest_to_int (expr
->elts
[endpos
- 2].longconst
);
993 case LOW_BOUND_DEFAULT
:
994 case LOW_BOUND_DEFAULT_EXCLUSIVE
:
995 case HIGH_BOUND_DEFAULT
:
998 case BOTH_BOUND_DEFAULT
:
1001 case NONE_BOUND_DEFAULT
:
1002 case NONE_BOUND_DEFAULT_EXCLUSIVE
:
1010 args
= 1 + (i
< (int) BINOP_END
);
1017 /* Copy the subexpression ending just before index INEND in INEXPR
1018 into OUTEXPR, starting at index OUTBEG.
1019 In the process, convert it from suffix to prefix form.
1020 If EXPOUT_LAST_STRUCT is -1, then this function always returns -1.
1021 Otherwise, it returns the index of the subexpression which is the
1022 left-hand-side of the expression at EXPOUT_LAST_STRUCT. */
1025 prefixify_subexp (struct expression
*inexpr
,
1026 struct expression
*outexpr
, int inend
, int outbeg
)
1034 operator_length (inexpr
, inend
, &oplen
, &args
);
1036 /* Copy the final operator itself, from the end of the input
1037 to the beginning of the output. */
1039 memcpy (&outexpr
->elts
[outbeg
], &inexpr
->elts
[inend
],
1040 EXP_ELEM_TO_BYTES (oplen
));
1043 if (expout_last_struct
== inend
)
1044 result
= outbeg
- oplen
;
1046 /* Find the lengths of the arg subexpressions. */
1047 arglens
= (int *) alloca (args
* sizeof (int));
1048 for (i
= args
- 1; i
>= 0; i
--)
1050 oplen
= length_of_subexp (inexpr
, inend
);
1055 /* Now copy each subexpression, preserving the order of
1056 the subexpressions, but prefixifying each one.
1057 In this loop, inend starts at the beginning of
1058 the expression this level is working on
1059 and marches forward over the arguments.
1060 outbeg does similarly in the output. */
1061 for (i
= 0; i
< args
; i
++)
1067 r
= prefixify_subexp (inexpr
, outexpr
, inend
, outbeg
);
1070 /* Return immediately. We probably have only parsed a
1071 partial expression, so we don't want to try to reverse
1072 the other operands. */
1081 /* Read an expression from the string *STRINGPTR points to,
1082 parse it, and return a pointer to a struct expression that we malloc.
1083 Use block BLOCK as the lexical context for variable names;
1084 if BLOCK is zero, use the block of the selected stack frame.
1085 Meanwhile, advance *STRINGPTR to point after the expression,
1086 at the first nonwhite character that is not part of the expression
1087 (possibly a null character).
1089 If COMMA is nonzero, stop if a comma is reached. */
1092 parse_exp_1 (const char **stringptr
, CORE_ADDR pc
, const struct block
*block
,
1093 int comma
, innermost_block_tracker_types tracker_types
)
1095 return parse_exp_in_context (stringptr
, pc
, block
, comma
, 0, NULL
,
1099 /* As for parse_exp_1, except that if VOID_CONTEXT_P, then
1100 no value is expected from the expression.
1101 OUT_SUBEXP is set when attempting to complete a field name; in this
1102 case it is set to the index of the subexpression on the
1103 left-hand-side of the struct op. If not doing such completion, it
1104 is left untouched. */
1106 static expression_up
1107 parse_exp_in_context (const char **stringptr
, CORE_ADDR pc
,
1108 const struct block
*block
,
1109 int comma
, int void_context_p
, int *out_subexp
,
1110 innermost_block_tracker_types tracker_types
)
1112 const struct language_defn
*lang
= NULL
;
1115 lexptr
= *stringptr
;
1118 type_stack
.elements
.clear ();
1119 expout_last_struct
= -1;
1120 expout_tag_completion_type
= TYPE_CODE_UNDEF
;
1121 expout_completion_name
.reset ();
1122 innermost_block
.reset (tracker_types
);
1124 if (lexptr
== 0 || *lexptr
== 0)
1125 error_no_arg (_("expression to compute"));
1127 std::vector
<int> funcalls
;
1128 scoped_restore save_funcall_chain
= make_scoped_restore (&funcall_chain
,
1131 const struct block
*expression_context_block
= block
;
1132 CORE_ADDR expression_context_pc
= 0;
1134 /* If no context specified, try using the current frame, if any. */
1135 if (!expression_context_block
)
1136 expression_context_block
= get_selected_block (&expression_context_pc
);
1138 expression_context_pc
= BLOCK_ENTRY_PC (expression_context_block
);
1140 expression_context_pc
= pc
;
1142 /* Fall back to using the current source static context, if any. */
1144 if (!expression_context_block
)
1146 struct symtab_and_line cursal
= get_current_source_symtab_and_line ();
1148 expression_context_block
1149 = BLOCKVECTOR_BLOCK (SYMTAB_BLOCKVECTOR (cursal
.symtab
),
1151 if (expression_context_block
)
1152 expression_context_pc
= BLOCK_ENTRY_PC (expression_context_block
);
1155 if (language_mode
== language_mode_auto
&& block
!= NULL
)
1157 /* Find the language associated to the given context block.
1158 Default to the current language if it can not be determined.
1160 Note that using the language corresponding to the current frame
1161 can sometimes give unexpected results. For instance, this
1162 routine is often called several times during the inferior
1163 startup phase to re-parse breakpoint expressions after
1164 a new shared library has been loaded. The language associated
1165 to the current frame at this moment is not relevant for
1166 the breakpoint. Using it would therefore be silly, so it seems
1167 better to rely on the current language rather than relying on
1168 the current frame language to parse the expression. That's why
1169 we do the following language detection only if the context block
1170 has been specifically provided. */
1171 struct symbol
*func
= block_linkage_function (block
);
1174 lang
= language_def (SYMBOL_LANGUAGE (func
));
1175 if (lang
== NULL
|| lang
->la_language
== language_unknown
)
1176 lang
= current_language
;
1179 lang
= current_language
;
1181 /* get_current_arch may reset CURRENT_LANGUAGE via select_frame.
1182 While we need CURRENT_LANGUAGE to be set to LANG (for lookup_symbol
1183 and others called from *.y) ensure CURRENT_LANGUAGE gets restored
1184 to the value matching SELECTED_FRAME as set by get_current_arch. */
1186 parser_state
ps (lang
, get_current_arch (), expression_context_block
,
1187 expression_context_pc
, comma
);
1189 scoped_restore_current_language lang_saver
;
1190 set_language (lang
->la_language
);
1194 lang
->la_parser (&ps
);
1196 CATCH (except
, RETURN_MASK_ALL
)
1198 /* If parsing for completion, allow this to succeed; but if no
1199 expression elements have been written, then there's nothing
1201 if (! parse_completion
|| ps
.expout_ptr
== 0)
1202 throw_exception (except
);
1206 /* We have to operate on an "expression *", due to la_post_parser,
1207 which explains this funny-looking double release. */
1208 expression_up result
= ps
.release ();
1210 /* Convert expression from postfix form as generated by yacc
1211 parser, to a prefix form. */
1213 if (expressiondebug
)
1214 dump_raw_expression (result
.get (), gdb_stdlog
,
1215 "before conversion to prefix form");
1217 subexp
= prefixify_expression (result
.get ());
1219 *out_subexp
= subexp
;
1221 lang
->la_post_parser (&result
, void_context_p
);
1223 if (expressiondebug
)
1224 dump_prefix_expression (result
.get (), gdb_stdlog
);
1226 *stringptr
= lexptr
;
1230 /* Parse STRING as an expression, and complain if this fails
1231 to use up all of the contents of STRING. */
1234 parse_expression (const char *string
)
1236 expression_up exp
= parse_exp_1 (&string
, 0, 0, 0);
1238 error (_("Junk after end of expression."));
1242 /* Same as parse_expression, but using the given language (LANG)
1243 to parse the expression. */
1246 parse_expression_with_language (const char *string
, enum language lang
)
1248 gdb::optional
<scoped_restore_current_language
> lang_saver
;
1249 if (current_language
->la_language
!= lang
)
1251 lang_saver
.emplace ();
1252 set_language (lang
);
1255 return parse_expression (string
);
1258 /* Parse STRING as an expression. If parsing ends in the middle of a
1259 field reference, return the type of the left-hand-side of the
1260 reference; furthermore, if the parsing ends in the field name,
1261 return the field name in *NAME. If the parsing ends in the middle
1262 of a field reference, but the reference is somehow invalid, throw
1263 an exception. In all other cases, return NULL. */
1266 parse_expression_for_completion (const char *string
,
1267 gdb::unique_xmalloc_ptr
<char> *name
,
1268 enum type_code
*code
)
1276 parse_completion
= 1;
1277 exp
= parse_exp_in_context (&string
, 0, 0, 0, 0, &subexp
,
1278 INNERMOST_BLOCK_FOR_SYMBOLS
);
1280 CATCH (except
, RETURN_MASK_ERROR
)
1282 /* Nothing, EXP remains NULL. */
1286 parse_completion
= 0;
1290 if (expout_tag_completion_type
!= TYPE_CODE_UNDEF
)
1292 *code
= expout_tag_completion_type
;
1293 *name
= std::move (expout_completion_name
);
1297 if (expout_last_struct
== -1)
1300 const char *fieldname
= extract_field_op (exp
.get (), &subexp
);
1301 if (fieldname
== NULL
)
1307 name
->reset (xstrdup (fieldname
));
1308 /* This might throw an exception. If so, we want to let it
1310 val
= evaluate_subexpression_type (exp
.get (), subexp
);
1312 return value_type (val
);
1315 /* A post-parser that does nothing. */
1318 null_post_parser (expression_up
*exp
, int void_context_p
)
1322 /* Parse floating point value P of length LEN.
1323 Return false if invalid, true if valid.
1324 The successfully parsed number is stored in DATA in
1325 target format for floating-point type TYPE.
1327 NOTE: This accepts the floating point syntax that sscanf accepts. */
1330 parse_float (const char *p
, int len
,
1331 const struct type
*type
, gdb_byte
*data
)
1333 return target_float_from_string (data
, type
, std::string (p
, len
));
1336 /* Stuff for maintaining a stack of types. Currently just used by C, but
1337 probably useful for any language which declares its types "backwards". */
1339 /* A helper function for insert_type and insert_type_address_space.
1340 This does work of expanding the type stack and inserting the new
1341 element, ELEMENT, into the stack at location SLOT. */
1344 insert_into_type_stack (int slot
, union type_stack_elt element
)
1346 gdb_assert (slot
<= type_stack
.elements
.size ());
1347 type_stack
.elements
.insert (type_stack
.elements
.begin () + slot
, element
);
1350 /* Insert a new type, TP, at the bottom of the type stack. If TP is
1351 tp_pointer, tp_reference or tp_rvalue_reference, it is inserted at the
1352 bottom. If TP is a qualifier, it is inserted at slot 1 (just above a
1353 previous tp_pointer) if there is anything on the stack, or simply pushed
1354 if the stack is empty. Other values for TP are invalid. */
1357 insert_type (enum type_pieces tp
)
1359 union type_stack_elt element
;
1362 gdb_assert (tp
== tp_pointer
|| tp
== tp_reference
1363 || tp
== tp_rvalue_reference
|| tp
== tp_const
1364 || tp
== tp_volatile
);
1366 /* If there is anything on the stack (we know it will be a
1367 tp_pointer), insert the qualifier above it. Otherwise, simply
1368 push this on the top of the stack. */
1369 if (!type_stack
.elements
.empty () && (tp
== tp_const
|| tp
== tp_volatile
))
1375 insert_into_type_stack (slot
, element
);
1379 push_type (enum type_pieces tp
)
1383 type_stack
.elements
.push_back (elt
);
1387 push_type_int (int n
)
1391 type_stack
.elements
.push_back (elt
);
1394 /* Insert a tp_space_identifier and the corresponding address space
1395 value into the stack. STRING is the name of an address space, as
1396 recognized by address_space_name_to_int. If the stack is empty,
1397 the new elements are simply pushed. If the stack is not empty,
1398 this function assumes that the first item on the stack is a
1399 tp_pointer, and the new values are inserted above the first
1403 insert_type_address_space (struct expr_builder
*pstate
, char *string
)
1405 union type_stack_elt element
;
1408 /* If there is anything on the stack (we know it will be a
1409 tp_pointer), insert the address space qualifier above it.
1410 Otherwise, simply push this on the top of the stack. */
1411 if (!type_stack
.elements
.empty ())
1416 element
.piece
= tp_space_identifier
;
1417 insert_into_type_stack (slot
, element
);
1418 element
.int_val
= address_space_name_to_int (pstate
->gdbarch (),
1420 insert_into_type_stack (slot
, element
);
1426 if (!type_stack
.elements
.empty ())
1428 type_stack_elt elt
= type_stack
.elements
.back ();
1429 type_stack
.elements
.pop_back ();
1438 if (!type_stack
.elements
.empty ())
1440 type_stack_elt elt
= type_stack
.elements
.back ();
1441 type_stack
.elements
.pop_back ();
1444 /* "Can't happen". */
1448 /* Pop a type list element from the global type stack. */
1450 static std::vector
<struct type
*> *
1453 gdb_assert (!type_stack
.elements
.empty ());
1454 type_stack_elt elt
= type_stack
.elements
.back ();
1455 type_stack
.elements
.pop_back ();
1456 return elt
.typelist_val
;
1459 /* Pop a type_stack element from the global type stack. */
1461 static struct type_stack
*
1462 pop_type_stack (void)
1464 gdb_assert (!type_stack
.elements
.empty ());
1465 type_stack_elt elt
= type_stack
.elements
.back ();
1466 type_stack
.elements
.pop_back ();
1467 return elt
.stack_val
;
1470 /* Append the elements of the type stack FROM to the type stack TO.
1471 Always returns TO. */
1474 append_type_stack (struct type_stack
*to
, struct type_stack
*from
)
1476 to
->elements
.insert (to
->elements
.end (), from
->elements
.begin (),
1477 from
->elements
.end ());
1481 /* Push the type stack STACK as an element on the global type stack. */
1484 push_type_stack (struct type_stack
*stack
)
1487 elt
.stack_val
= stack
;
1488 type_stack
.elements
.push_back (elt
);
1489 push_type (tp_type_stack
);
1492 /* Copy the global type stack into a newly allocated type stack and
1493 return it. The global stack is cleared. The returned type stack
1494 must be freed with delete. */
1497 get_type_stack (void)
1499 struct type_stack
*result
= new struct type_stack (std::move (type_stack
));
1500 type_stack
.elements
.clear ();
1504 /* Push a function type with arguments onto the global type stack.
1505 LIST holds the argument types. If the final item in LIST is NULL,
1506 then the function will be varargs. */
1509 push_typelist (std::vector
<struct type
*> *list
)
1512 elt
.typelist_val
= list
;
1513 type_stack
.elements
.push_back (elt
);
1514 push_type (tp_function_with_arguments
);
1517 /* Pop the type stack and return a type_instance_flags that
1518 corresponds the const/volatile qualifiers on the stack. This is
1519 called by the C++ parser when parsing methods types, and as such no
1520 other kind of type in the type stack is expected. */
1523 follow_type_instance_flags ()
1525 type_instance_flags flags
= 0;
1528 switch (pop_type ())
1533 flags
|= TYPE_INSTANCE_FLAG_CONST
;
1536 flags
|= TYPE_INSTANCE_FLAG_VOLATILE
;
1539 gdb_assert_not_reached ("unrecognized tp_ value in follow_types");
1544 /* Pop the type stack and return the type which corresponds to FOLLOW_TYPE
1545 as modified by all the stuff on the stack. */
1547 follow_types (struct type
*follow_type
)
1551 int make_volatile
= 0;
1552 int make_addr_space
= 0;
1556 switch (pop_type ())
1561 follow_type
= make_cv_type (make_const
,
1562 TYPE_VOLATILE (follow_type
),
1565 follow_type
= make_cv_type (TYPE_CONST (follow_type
),
1568 if (make_addr_space
)
1569 follow_type
= make_type_with_address_space (follow_type
,
1571 make_const
= make_volatile
= 0;
1572 make_addr_space
= 0;
1580 case tp_space_identifier
:
1581 make_addr_space
= pop_type_int ();
1584 follow_type
= lookup_pointer_type (follow_type
);
1586 follow_type
= make_cv_type (make_const
,
1587 TYPE_VOLATILE (follow_type
),
1590 follow_type
= make_cv_type (TYPE_CONST (follow_type
),
1593 if (make_addr_space
)
1594 follow_type
= make_type_with_address_space (follow_type
,
1596 make_const
= make_volatile
= 0;
1597 make_addr_space
= 0;
1600 follow_type
= lookup_lvalue_reference_type (follow_type
);
1601 goto process_reference
;
1602 case tp_rvalue_reference
:
1603 follow_type
= lookup_rvalue_reference_type (follow_type
);
1606 follow_type
= make_cv_type (make_const
,
1607 TYPE_VOLATILE (follow_type
),
1610 follow_type
= make_cv_type (TYPE_CONST (follow_type
),
1613 if (make_addr_space
)
1614 follow_type
= make_type_with_address_space (follow_type
,
1616 make_const
= make_volatile
= 0;
1617 make_addr_space
= 0;
1620 array_size
= pop_type_int ();
1621 /* FIXME-type-allocation: need a way to free this type when we are
1624 lookup_array_range_type (follow_type
,
1625 0, array_size
>= 0 ? array_size
- 1 : 0);
1627 TYPE_HIGH_BOUND_KIND (TYPE_INDEX_TYPE (follow_type
))
1631 /* FIXME-type-allocation: need a way to free this type when we are
1633 follow_type
= lookup_function_type (follow_type
);
1636 case tp_function_with_arguments
:
1638 std::vector
<struct type
*> *args
= pop_typelist ();
1641 = lookup_function_type_with_arguments (follow_type
,
1649 struct type_stack
*stack
= pop_type_stack ();
1650 /* Sort of ugly, but not really much worse than the
1652 struct type_stack save
= type_stack
;
1654 type_stack
= *stack
;
1655 follow_type
= follow_types (follow_type
);
1656 gdb_assert (type_stack
.elements
.empty ());
1662 gdb_assert_not_reached ("unrecognized tp_ value in follow_types");
1667 /* This function avoids direct calls to fprintf
1668 in the parser generated debug code. */
1670 parser_fprintf (FILE *x
, const char *y
, ...)
1676 vfprintf_unfiltered (gdb_stderr
, y
, args
);
1679 fprintf_unfiltered (gdb_stderr
, " Unknown FILE used.\n");
1680 vfprintf_unfiltered (gdb_stderr
, y
, args
);
1685 /* Implementation of the exp_descriptor method operator_check. */
1688 operator_check_standard (struct expression
*exp
, int pos
,
1689 int (*objfile_func
) (struct objfile
*objfile
,
1693 const union exp_element
*const elts
= exp
->elts
;
1694 struct type
*type
= NULL
;
1695 struct objfile
*objfile
= NULL
;
1697 /* Extended operators should have been already handled by exp_descriptor
1698 iterate method of its specific language. */
1699 gdb_assert (elts
[pos
].opcode
< OP_EXTENDED0
);
1701 /* Track the callers of write_exp_elt_type for this table. */
1703 switch (elts
[pos
].opcode
)
1715 type
= elts
[pos
+ 1].type
;
1720 LONGEST arg
, nargs
= elts
[pos
+ 2].longconst
;
1722 for (arg
= 0; arg
< nargs
; arg
++)
1724 struct type
*inst_type
= elts
[pos
+ 3 + arg
].type
;
1725 struct objfile
*inst_objfile
= TYPE_OBJFILE (inst_type
);
1727 if (inst_objfile
&& (*objfile_func
) (inst_objfile
, data
))
1735 const struct block
*const block
= elts
[pos
+ 1].block
;
1736 const struct symbol
*const symbol
= elts
[pos
+ 2].symbol
;
1738 /* Check objfile where the variable itself is placed.
1739 SYMBOL_OBJ_SECTION (symbol) may be NULL. */
1740 if ((*objfile_func
) (symbol_objfile (symbol
), data
))
1743 /* Check objfile where is placed the code touching the variable. */
1744 objfile
= lookup_objfile_from_block (block
);
1746 type
= SYMBOL_TYPE (symbol
);
1749 case OP_VAR_MSYM_VALUE
:
1750 objfile
= elts
[pos
+ 1].objfile
;
1754 /* Invoke callbacks for TYPE and OBJFILE if they were set as non-NULL. */
1756 if (type
&& TYPE_OBJFILE (type
)
1757 && (*objfile_func
) (TYPE_OBJFILE (type
), data
))
1759 if (objfile
&& (*objfile_func
) (objfile
, data
))
1765 /* Call OBJFILE_FUNC for any objfile found being referenced by EXP.
1766 OBJFILE_FUNC is never called with NULL OBJFILE. OBJFILE_FUNC get
1767 passed an arbitrary caller supplied DATA pointer. If OBJFILE_FUNC
1768 returns non-zero value then (any other) non-zero value is immediately
1769 returned to the caller. Otherwise zero is returned after iterating
1770 through whole EXP. */
1773 exp_iterate (struct expression
*exp
,
1774 int (*objfile_func
) (struct objfile
*objfile
, void *data
),
1779 for (endpos
= exp
->nelts
; endpos
> 0; )
1781 int pos
, args
, oplen
= 0;
1783 operator_length (exp
, endpos
, &oplen
, &args
);
1784 gdb_assert (oplen
> 0);
1786 pos
= endpos
- oplen
;
1787 if (exp
->language_defn
->la_exp_desc
->operator_check (exp
, pos
,
1788 objfile_func
, data
))
1797 /* Helper for exp_uses_objfile. */
1800 exp_uses_objfile_iter (struct objfile
*exp_objfile
, void *objfile_voidp
)
1802 struct objfile
*objfile
= (struct objfile
*) objfile_voidp
;
1804 if (exp_objfile
->separate_debug_objfile_backlink
)
1805 exp_objfile
= exp_objfile
->separate_debug_objfile_backlink
;
1807 return exp_objfile
== objfile
;
1810 /* Return 1 if EXP uses OBJFILE (and will become dangling when OBJFILE
1811 is unloaded), otherwise return 0. OBJFILE must not be a separate debug info
1815 exp_uses_objfile (struct expression
*exp
, struct objfile
*objfile
)
1817 gdb_assert (objfile
->separate_debug_objfile_backlink
== NULL
);
1819 return exp_iterate (exp
, exp_uses_objfile_iter
, objfile
);
1822 /* Reallocate the `expout' pointer inside PS so that it can accommodate
1823 at least LENELT expression elements. This function does nothing if
1824 there is enough room for the elements. */
1827 increase_expout_size (struct expr_builder
*ps
, size_t lenelt
)
1829 if ((ps
->expout_ptr
+ lenelt
) >= ps
->expout_size
)
1831 ps
->expout_size
= std::max (ps
->expout_size
* 2,
1832 ps
->expout_ptr
+ lenelt
+ 10);
1833 ps
->expout
.reset (XRESIZEVAR (expression
,
1834 ps
->expout
.release (),
1835 (sizeof (struct expression
)
1836 + EXP_ELEM_TO_BYTES (ps
->expout_size
))));
1841 _initialize_parse (void)
1843 add_setshow_zuinteger_cmd ("expression", class_maintenance
,
1845 _("Set expression debugging."),
1846 _("Show expression debugging."),
1847 _("When non-zero, the internal representation "
1848 "of expressions will be printed."),
1850 show_expressiondebug
,
1851 &setdebuglist
, &showdebuglist
);
1852 add_setshow_boolean_cmd ("parser", class_maintenance
,
1854 _("Set parser debugging."),
1855 _("Show parser debugging."),
1856 _("When non-zero, expression parser "
1857 "tracing will be enabled."),
1860 &setdebuglist
, &showdebuglist
);