1 /* Parse expressions for GDB.
3 Copyright (C) 1986, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997,
4 1998, 1999, 2000, 2001, 2004, 2005, 2007, 2008, 2009, 2010
5 Free Software Foundation, Inc.
7 Modified from expread.y by the Department of Computer Science at the
8 State University of New York at Buffalo, 1991.
10 This file is part of GDB.
12 This program is free software; you can redistribute it and/or modify
13 it under the terms of the GNU General Public License as published by
14 the Free Software Foundation; either version 3 of the License, or
15 (at your option) any later version.
17 This program is distributed in the hope that it will be useful,
18 but WITHOUT ANY WARRANTY; without even the implied warranty of
19 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 GNU General Public License for more details.
22 You should have received a copy of the GNU General Public License
23 along with this program. If not, see <http://www.gnu.org/licenses/>. */
25 /* Parse an expression from text in a string,
26 and return the result as a struct expression pointer.
27 That structure contains arithmetic operations in reverse polish,
28 with constants represented by operations that are followed by special data.
29 See expression.h for the details of the format.
30 What is important here is that it can be built up sequentially
31 during the process of parsing; the lower levels of the tree always
32 come first in the result. */
36 #include "arch-utils.h"
37 #include "gdb_string.h"
41 #include "expression.h"
46 #include "parser-defs.h"
48 #include "symfile.h" /* for overlay functions */
51 #include "gdb_assert.h"
55 #include "exceptions.h"
56 #include "user-regs.h"
58 /* Standard set of definitions for printing, dumping, prefixifying,
59 * and evaluating expressions. */
61 const struct exp_descriptor exp_descriptor_standard
=
63 print_subexp_standard
,
64 operator_length_standard
,
65 operator_check_standard
,
67 dump_subexp_body_standard
,
68 evaluate_subexp_standard
71 /* Global variables declared in parser-defs.h (and commented there). */
72 struct expression
*expout
;
75 struct block
*expression_context_block
;
76 CORE_ADDR expression_context_pc
;
77 struct block
*innermost_block
;
79 union type_stack_elt
*type_stack
;
80 int type_stack_depth
, type_stack_size
;
86 /* True if parsing an expression to find a field reference. This is
87 only used by completion. */
90 /* The index of the last struct expression directly before a '.' or
91 '->'. This is set when parsing and is only used when completing a
92 field name. It is -1 if no dereference operation was found. */
93 static int expout_last_struct
= -1;
95 /* A temporary buffer for identifiers, so we can null-terminate them.
97 We allocate this with xrealloc. parse_exp_1 used to allocate with
98 alloca, using the size of the whole expression as a conservative
99 estimate of the space needed. However, macro expansion can
100 introduce names longer than the original expression; there's no
101 practical way to know beforehand how large that might be. */
103 size_t namecopy_size
;
105 static int expressiondebug
= 0;
107 show_expressiondebug (struct ui_file
*file
, int from_tty
,
108 struct cmd_list_element
*c
, const char *value
)
110 fprintf_filtered (file
, _("Expression debugging is %s.\n"), value
);
114 /* Non-zero if an expression parser should set yydebug. */
118 show_parserdebug (struct ui_file
*file
, int from_tty
,
119 struct cmd_list_element
*c
, const char *value
)
121 fprintf_filtered (file
, _("Parser debugging is %s.\n"), value
);
125 static void free_funcalls (void *ignore
);
127 static int prefixify_expression (struct expression
*);
129 static int prefixify_subexp (struct expression
*, struct expression
*, int,
132 static struct expression
*parse_exp_in_context (char **, struct block
*, int,
135 void _initialize_parse (void);
137 /* Data structure for saving values of arglist_len for function calls whose
138 arguments contain other function calls. */
142 struct funcall
*next
;
146 static struct funcall
*funcall_chain
;
148 /* Begin counting arguments for a function call,
149 saving the data about any containing call. */
156 new = (struct funcall
*) xmalloc (sizeof (struct funcall
));
157 new->next
= funcall_chain
;
158 new->arglist_len
= arglist_len
;
163 /* Return the number of arguments in a function call just terminated,
164 and restore the data for the containing function call. */
169 int val
= arglist_len
;
170 struct funcall
*call
= funcall_chain
;
172 funcall_chain
= call
->next
;
173 arglist_len
= call
->arglist_len
;
178 /* Free everything in the funcall chain.
179 Used when there is an error inside parsing. */
182 free_funcalls (void *ignore
)
184 struct funcall
*call
, *next
;
186 for (call
= funcall_chain
; call
; call
= next
)
193 /* This page contains the functions for adding data to the struct expression
194 being constructed. */
196 /* Add one element to the end of the expression. */
198 /* To avoid a bug in the Sun 4 compiler, we pass things that can fit into
199 a register through here */
202 write_exp_elt (union exp_element expelt
)
204 if (expout_ptr
>= expout_size
)
207 expout
= (struct expression
*)
208 xrealloc ((char *) expout
, sizeof (struct expression
)
209 + EXP_ELEM_TO_BYTES (expout_size
));
211 expout
->elts
[expout_ptr
++] = expelt
;
215 write_exp_elt_opcode (enum exp_opcode expelt
)
217 union exp_element tmp
;
219 memset (&tmp
, 0, sizeof (union exp_element
));
225 write_exp_elt_sym (struct symbol
*expelt
)
227 union exp_element tmp
;
229 memset (&tmp
, 0, sizeof (union exp_element
));
235 write_exp_elt_block (struct block
*b
)
237 union exp_element tmp
;
239 memset (&tmp
, 0, sizeof (union exp_element
));
245 write_exp_elt_objfile (struct objfile
*objfile
)
247 union exp_element tmp
;
249 memset (&tmp
, 0, sizeof (union exp_element
));
250 tmp
.objfile
= objfile
;
255 write_exp_elt_longcst (LONGEST expelt
)
257 union exp_element tmp
;
259 memset (&tmp
, 0, sizeof (union exp_element
));
260 tmp
.longconst
= expelt
;
265 write_exp_elt_dblcst (DOUBLEST expelt
)
267 union exp_element tmp
;
269 memset (&tmp
, 0, sizeof (union exp_element
));
270 tmp
.doubleconst
= expelt
;
275 write_exp_elt_decfloatcst (gdb_byte expelt
[16])
277 union exp_element tmp
;
280 for (index
= 0; index
< 16; index
++)
281 tmp
.decfloatconst
[index
] = expelt
[index
];
287 write_exp_elt_type (struct type
*expelt
)
289 union exp_element tmp
;
291 memset (&tmp
, 0, sizeof (union exp_element
));
297 write_exp_elt_intern (struct internalvar
*expelt
)
299 union exp_element tmp
;
301 memset (&tmp
, 0, sizeof (union exp_element
));
302 tmp
.internalvar
= expelt
;
306 /* Add a string constant to the end of the expression.
308 String constants are stored by first writing an expression element
309 that contains the length of the string, then stuffing the string
310 constant itself into however many expression elements are needed
311 to hold it, and then writing another expression element that contains
312 the length of the string. I.E. an expression element at each end of
313 the string records the string length, so you can skip over the
314 expression elements containing the actual string bytes from either
315 end of the string. Note that this also allows gdb to handle
316 strings with embedded null bytes, as is required for some languages.
318 Don't be fooled by the fact that the string is null byte terminated,
319 this is strictly for the convenience of debugging gdb itself.
320 Gdb does not depend up the string being null terminated, since the
321 actual length is recorded in expression elements at each end of the
322 string. The null byte is taken into consideration when computing how
323 many expression elements are required to hold the string constant, of
328 write_exp_string (struct stoken str
)
330 int len
= str
.length
;
334 /* Compute the number of expression elements required to hold the string
335 (including a null byte terminator), along with one expression element
336 at each end to record the actual string length (not including the
337 null byte terminator). */
339 lenelt
= 2 + BYTES_TO_EXP_ELEM (len
+ 1);
341 /* Ensure that we have enough available expression elements to store
344 if ((expout_ptr
+ lenelt
) >= expout_size
)
346 expout_size
= max (expout_size
* 2, expout_ptr
+ lenelt
+ 10);
347 expout
= (struct expression
*)
348 xrealloc ((char *) expout
, (sizeof (struct expression
)
349 + EXP_ELEM_TO_BYTES (expout_size
)));
352 /* Write the leading length expression element (which advances the current
353 expression element index), then write the string constant followed by a
354 terminating null byte, and then write the trailing length expression
357 write_exp_elt_longcst ((LONGEST
) len
);
358 strdata
= (char *) &expout
->elts
[expout_ptr
];
359 memcpy (strdata
, str
.ptr
, len
);
360 *(strdata
+ len
) = '\0';
361 expout_ptr
+= lenelt
- 2;
362 write_exp_elt_longcst ((LONGEST
) len
);
365 /* Add a vector of string constants to the end of the expression.
367 This adds an OP_STRING operation, but encodes the contents
368 differently from write_exp_string. The language is expected to
369 handle evaluation of this expression itself.
371 After the usual OP_STRING header, TYPE is written into the
372 expression as a long constant. The interpretation of this field is
373 up to the language evaluator.
375 Next, each string in VEC is written. The length is written as a
376 long constant, followed by the contents of the string. */
379 write_exp_string_vector (int type
, struct stoken_vector
*vec
)
383 /* Compute the size. We compute the size in number of slots to
384 avoid issues with string padding. */
386 for (i
= 0; i
< vec
->len
; ++i
)
388 /* One slot for the length of this element, plus the number of
389 slots needed for this string. */
390 n_slots
+= 1 + BYTES_TO_EXP_ELEM (vec
->tokens
[i
].length
);
393 /* One more slot for the type of the string. */
396 /* Now compute a phony string length. */
397 len
= EXP_ELEM_TO_BYTES (n_slots
) - 1;
400 if ((expout_ptr
+ n_slots
) >= expout_size
)
402 expout_size
= max (expout_size
* 2, expout_ptr
+ n_slots
+ 10);
403 expout
= (struct expression
*)
404 xrealloc ((char *) expout
, (sizeof (struct expression
)
405 + EXP_ELEM_TO_BYTES (expout_size
)));
408 write_exp_elt_opcode (OP_STRING
);
409 write_exp_elt_longcst (len
);
410 write_exp_elt_longcst (type
);
412 for (i
= 0; i
< vec
->len
; ++i
)
414 write_exp_elt_longcst (vec
->tokens
[i
].length
);
415 memcpy (&expout
->elts
[expout_ptr
], vec
->tokens
[i
].ptr
,
416 vec
->tokens
[i
].length
);
417 expout_ptr
+= BYTES_TO_EXP_ELEM (vec
->tokens
[i
].length
);
420 write_exp_elt_longcst (len
);
421 write_exp_elt_opcode (OP_STRING
);
424 /* Add a bitstring constant to the end of the expression.
426 Bitstring constants are stored by first writing an expression element
427 that contains the length of the bitstring (in bits), then stuffing the
428 bitstring constant itself into however many expression elements are
429 needed to hold it, and then writing another expression element that
430 contains the length of the bitstring. I.E. an expression element at
431 each end of the bitstring records the bitstring length, so you can skip
432 over the expression elements containing the actual bitstring bytes from
433 either end of the bitstring. */
436 write_exp_bitstring (struct stoken str
)
438 int bits
= str
.length
; /* length in bits */
439 int len
= (bits
+ HOST_CHAR_BIT
- 1) / HOST_CHAR_BIT
;
443 /* Compute the number of expression elements required to hold the bitstring,
444 along with one expression element at each end to record the actual
445 bitstring length in bits. */
447 lenelt
= 2 + BYTES_TO_EXP_ELEM (len
);
449 /* Ensure that we have enough available expression elements to store
452 if ((expout_ptr
+ lenelt
) >= expout_size
)
454 expout_size
= max (expout_size
* 2, expout_ptr
+ lenelt
+ 10);
455 expout
= (struct expression
*)
456 xrealloc ((char *) expout
, (sizeof (struct expression
)
457 + EXP_ELEM_TO_BYTES (expout_size
)));
460 /* Write the leading length expression element (which advances the current
461 expression element index), then write the bitstring constant, and then
462 write the trailing length expression element. */
464 write_exp_elt_longcst ((LONGEST
) bits
);
465 strdata
= (char *) &expout
->elts
[expout_ptr
];
466 memcpy (strdata
, str
.ptr
, len
);
467 expout_ptr
+= lenelt
- 2;
468 write_exp_elt_longcst ((LONGEST
) bits
);
471 /* Add the appropriate elements for a minimal symbol to the end of
475 write_exp_msymbol (struct minimal_symbol
*msymbol
)
477 struct objfile
*objfile
= msymbol_objfile (msymbol
);
478 struct gdbarch
*gdbarch
= get_objfile_arch (objfile
);
480 CORE_ADDR addr
= SYMBOL_VALUE_ADDRESS (msymbol
);
481 struct obj_section
*section
= SYMBOL_OBJ_SECTION (msymbol
);
482 enum minimal_symbol_type type
= MSYMBOL_TYPE (msymbol
);
485 /* The minimal symbol might point to a function descriptor;
486 resolve it to the actual code address instead. */
487 pc
= gdbarch_convert_from_func_ptr_addr (gdbarch
, addr
, ¤t_target
);
490 /* In this case, assume we have a code symbol instead of
497 if (overlay_debugging
)
498 addr
= symbol_overlayed_address (addr
, section
);
500 write_exp_elt_opcode (OP_LONG
);
501 /* Let's make the type big enough to hold a 64-bit address. */
502 write_exp_elt_type (objfile_type (objfile
)->builtin_core_addr
);
503 write_exp_elt_longcst ((LONGEST
) addr
);
504 write_exp_elt_opcode (OP_LONG
);
506 if (section
&& section
->the_bfd_section
->flags
& SEC_THREAD_LOCAL
)
508 write_exp_elt_opcode (UNOP_MEMVAL_TLS
);
509 write_exp_elt_objfile (objfile
);
510 write_exp_elt_type (objfile_type (objfile
)->nodebug_tls_symbol
);
511 write_exp_elt_opcode (UNOP_MEMVAL_TLS
);
515 write_exp_elt_opcode (UNOP_MEMVAL
);
520 case mst_solib_trampoline
:
521 write_exp_elt_type (objfile_type (objfile
)->nodebug_text_symbol
);
528 write_exp_elt_type (objfile_type (objfile
)->nodebug_data_symbol
);
532 write_exp_elt_type (objfile_type (objfile
)->nodebug_unknown_symbol
);
535 write_exp_elt_opcode (UNOP_MEMVAL
);
538 /* Mark the current index as the starting location of a structure
539 expression. This is used when completing on field names. */
542 mark_struct_expression (void)
544 expout_last_struct
= expout_ptr
;
548 /* Recognize tokens that start with '$'. These include:
550 $regname A native register name or a "standard
553 $variable A convenience variable with a name chosen
556 $digits Value history with index <digits>, starting
557 from the first value which has index 1.
559 $$digits Value history with index <digits> relative
560 to the last value. I.E. $$0 is the last
561 value, $$1 is the one previous to that, $$2
562 is the one previous to $$1, etc.
564 $ | $0 | $$0 The last value in the value history.
566 $$ An abbreviation for the second to the last
567 value in the value history, I.E. $$1
572 write_dollar_variable (struct stoken str
)
574 struct symbol
*sym
= NULL
;
575 struct minimal_symbol
*msym
= NULL
;
576 struct internalvar
*isym
= NULL
;
578 /* Handle the tokens $digits; also $ (short for $0) and $$ (short for $$1)
579 and $$digits (equivalent to $<-digits> if you could type that). */
583 /* Double dollar means negate the number and add -1 as well.
584 Thus $$ alone means -1. */
585 if (str
.length
>= 2 && str
.ptr
[1] == '$')
592 /* Just dollars (one or two) */
596 /* Is the rest of the token digits? */
597 for (; i
< str
.length
; i
++)
598 if (!(str
.ptr
[i
] >= '0' && str
.ptr
[i
] <= '9'))
602 i
= atoi (str
.ptr
+ 1 + negate
);
608 /* Handle tokens that refer to machine registers:
609 $ followed by a register name. */
610 i
= user_reg_map_name_to_regnum (parse_gdbarch
,
611 str
.ptr
+ 1, str
.length
- 1);
613 goto handle_register
;
615 /* Any names starting with $ are probably debugger internal variables. */
617 isym
= lookup_only_internalvar (copy_name (str
) + 1);
620 write_exp_elt_opcode (OP_INTERNALVAR
);
621 write_exp_elt_intern (isym
);
622 write_exp_elt_opcode (OP_INTERNALVAR
);
626 /* On some systems, such as HP-UX and hppa-linux, certain system routines
627 have names beginning with $ or $$. Check for those, first. */
629 sym
= lookup_symbol (copy_name (str
), (struct block
*) NULL
,
630 VAR_DOMAIN
, (int *) NULL
);
633 write_exp_elt_opcode (OP_VAR_VALUE
);
634 write_exp_elt_block (block_found
); /* set by lookup_symbol */
635 write_exp_elt_sym (sym
);
636 write_exp_elt_opcode (OP_VAR_VALUE
);
639 msym
= lookup_minimal_symbol (copy_name (str
), NULL
, NULL
);
642 write_exp_msymbol (msym
);
646 /* Any other names are assumed to be debugger internal variables. */
648 write_exp_elt_opcode (OP_INTERNALVAR
);
649 write_exp_elt_intern (create_internalvar (copy_name (str
) + 1));
650 write_exp_elt_opcode (OP_INTERNALVAR
);
653 write_exp_elt_opcode (OP_LAST
);
654 write_exp_elt_longcst ((LONGEST
) i
);
655 write_exp_elt_opcode (OP_LAST
);
658 write_exp_elt_opcode (OP_REGISTER
);
661 write_exp_string (str
);
662 write_exp_elt_opcode (OP_REGISTER
);
668 find_template_name_end (char *p
)
671 int just_seen_right
= 0;
672 int just_seen_colon
= 0;
673 int just_seen_space
= 0;
675 if (!p
|| (*p
!= '<'))
686 /* In future, may want to allow these?? */
689 depth
++; /* start nested template */
690 if (just_seen_colon
|| just_seen_right
|| just_seen_space
)
691 return 0; /* but not after : or :: or > or space */
694 if (just_seen_colon
|| just_seen_right
)
695 return 0; /* end a (nested?) template */
696 just_seen_right
= 1; /* but not after : or :: */
697 if (--depth
== 0) /* also disallow >>, insist on > > */
698 return ++p
; /* if outermost ended, return */
701 if (just_seen_space
|| (just_seen_colon
> 1))
702 return 0; /* nested class spec coming up */
703 just_seen_colon
++; /* we allow :: but not :::: */
708 if (!((*p
>= 'a' && *p
<= 'z') || /* allow token chars */
709 (*p
>= 'A' && *p
<= 'Z') ||
710 (*p
>= '0' && *p
<= '9') ||
711 (*p
== '_') || (*p
== ',') || /* commas for template args */
712 (*p
== '&') || (*p
== '*') || /* pointer and ref types */
713 (*p
== '(') || (*p
== ')') || /* function types */
714 (*p
== '[') || (*p
== ']'))) /* array types */
729 /* Return a null-terminated temporary copy of the name
730 of a string token. */
733 copy_name (struct stoken token
)
735 /* Make sure there's enough space for the token. */
736 if (namecopy_size
< token
.length
+ 1)
738 namecopy_size
= token
.length
+ 1;
739 namecopy
= xrealloc (namecopy
, token
.length
+ 1);
742 memcpy (namecopy
, token
.ptr
, token
.length
);
743 namecopy
[token
.length
] = 0;
748 /* Reverse an expression from suffix form (in which it is constructed)
749 to prefix form (in which we can conveniently print or execute it).
750 Ordinarily this always returns -1. However, if EXPOUT_LAST_STRUCT
751 is not -1 (i.e., we are trying to complete a field name), it will
752 return the index of the subexpression which is the left-hand-side
753 of the struct operation at EXPOUT_LAST_STRUCT. */
756 prefixify_expression (struct expression
*expr
)
758 int len
= sizeof (struct expression
) + EXP_ELEM_TO_BYTES (expr
->nelts
);
759 struct expression
*temp
;
760 int inpos
= expr
->nelts
, outpos
= 0;
762 temp
= (struct expression
*) alloca (len
);
764 /* Copy the original expression into temp. */
765 memcpy (temp
, expr
, len
);
767 return prefixify_subexp (temp
, expr
, inpos
, outpos
);
770 /* Return the number of exp_elements in the postfix subexpression
771 of EXPR whose operator is at index ENDPOS - 1 in EXPR. */
774 length_of_subexp (struct expression
*expr
, int endpos
)
778 operator_length (expr
, endpos
, &oplen
, &args
);
782 oplen
+= length_of_subexp (expr
, endpos
- oplen
);
789 /* Sets *OPLENP to the length of the operator whose (last) index is
790 ENDPOS - 1 in EXPR, and sets *ARGSP to the number of arguments that
794 operator_length (struct expression
*expr
, int endpos
, int *oplenp
, int *argsp
)
796 expr
->language_defn
->la_exp_desc
->operator_length (expr
, endpos
,
800 /* Default value for operator_length in exp_descriptor vectors. */
803 operator_length_standard (struct expression
*expr
, int endpos
,
804 int *oplenp
, int *argsp
)
808 enum f90_range_type range_type
;
812 error (_("?error in operator_length_standard"));
814 i
= (int) expr
->elts
[endpos
- 1].opcode
;
820 oplen
= longest_to_int (expr
->elts
[endpos
- 2].longconst
);
821 oplen
= 5 + BYTES_TO_EXP_ELEM (oplen
+ 1);
844 case OP_F77_UNDETERMINED_ARGLIST
:
846 args
= 1 + longest_to_int (expr
->elts
[endpos
- 2].longconst
);
850 oplen
= 4 + longest_to_int (expr
->elts
[endpos
- 2].longconst
);
854 case OP_OBJC_MSGCALL
: /* Objective C message (method) call */
856 args
= 1 + longest_to_int (expr
->elts
[endpos
- 2].longconst
);
866 case UNOP_DYNAMIC_CAST
:
867 case UNOP_REINTERPRET_CAST
:
873 case UNOP_MEMVAL_TLS
:
891 oplen
= longest_to_int (expr
->elts
[endpos
- 2].longconst
);
892 oplen
= 4 + BYTES_TO_EXP_ELEM (oplen
+ 1);
898 case STRUCTOP_STRUCT
:
905 case OP_OBJC_NSSTRING
: /* Objective C Foundation Class NSString constant */
906 case OP_OBJC_SELECTOR
: /* Objective C "@selector" pseudo-op */
908 oplen
= longest_to_int (expr
->elts
[endpos
- 2].longconst
);
909 oplen
= 4 + BYTES_TO_EXP_ELEM (oplen
+ 1);
913 oplen
= longest_to_int (expr
->elts
[endpos
- 2].longconst
);
914 oplen
= (oplen
+ HOST_CHAR_BIT
- 1) / HOST_CHAR_BIT
;
915 oplen
= 4 + BYTES_TO_EXP_ELEM (oplen
);
920 args
= longest_to_int (expr
->elts
[endpos
- 2].longconst
);
921 args
-= longest_to_int (expr
->elts
[endpos
- 3].longconst
);
927 case TERNOP_SLICE_COUNT
:
932 case MULTI_SUBSCRIPT
:
934 args
= 1 + longest_to_int (expr
->elts
[endpos
- 2].longconst
);
937 case BINOP_ASSIGN_MODIFY
:
951 range_type
= longest_to_int (expr
->elts
[endpos
- 2].longconst
);
954 case LOW_BOUND_DEFAULT
:
955 case HIGH_BOUND_DEFAULT
:
958 case BOTH_BOUND_DEFAULT
:
961 case NONE_BOUND_DEFAULT
:
969 args
= 1 + (i
< (int) BINOP_END
);
976 /* Copy the subexpression ending just before index INEND in INEXPR
977 into OUTEXPR, starting at index OUTBEG.
978 In the process, convert it from suffix to prefix form.
979 If EXPOUT_LAST_STRUCT is -1, then this function always returns -1.
980 Otherwise, it returns the index of the subexpression which is the
981 left-hand-side of the expression at EXPOUT_LAST_STRUCT. */
984 prefixify_subexp (struct expression
*inexpr
,
985 struct expression
*outexpr
, int inend
, int outbeg
)
993 operator_length (inexpr
, inend
, &oplen
, &args
);
995 /* Copy the final operator itself, from the end of the input
996 to the beginning of the output. */
998 memcpy (&outexpr
->elts
[outbeg
], &inexpr
->elts
[inend
],
999 EXP_ELEM_TO_BYTES (oplen
));
1002 if (expout_last_struct
== inend
)
1003 result
= outbeg
- oplen
;
1005 /* Find the lengths of the arg subexpressions. */
1006 arglens
= (int *) alloca (args
* sizeof (int));
1007 for (i
= args
- 1; i
>= 0; i
--)
1009 oplen
= length_of_subexp (inexpr
, inend
);
1014 /* Now copy each subexpression, preserving the order of
1015 the subexpressions, but prefixifying each one.
1016 In this loop, inend starts at the beginning of
1017 the expression this level is working on
1018 and marches forward over the arguments.
1019 outbeg does similarly in the output. */
1020 for (i
= 0; i
< args
; i
++)
1026 r
= prefixify_subexp (inexpr
, outexpr
, inend
, outbeg
);
1029 /* Return immediately. We probably have only parsed a
1030 partial expression, so we don't want to try to reverse
1031 the other operands. */
1040 /* This page contains the two entry points to this file. */
1042 /* Read an expression from the string *STRINGPTR points to,
1043 parse it, and return a pointer to a struct expression that we malloc.
1044 Use block BLOCK as the lexical context for variable names;
1045 if BLOCK is zero, use the block of the selected stack frame.
1046 Meanwhile, advance *STRINGPTR to point after the expression,
1047 at the first nonwhite character that is not part of the expression
1048 (possibly a null character).
1050 If COMMA is nonzero, stop if a comma is reached. */
1053 parse_exp_1 (char **stringptr
, struct block
*block
, int comma
)
1055 return parse_exp_in_context (stringptr
, block
, comma
, 0, NULL
);
1058 /* As for parse_exp_1, except that if VOID_CONTEXT_P, then
1059 no value is expected from the expression.
1060 OUT_SUBEXP is set when attempting to complete a field name; in this
1061 case it is set to the index of the subexpression on the
1062 left-hand-side of the struct op. If not doing such completion, it
1063 is left untouched. */
1065 static struct expression
*
1066 parse_exp_in_context (char **stringptr
, struct block
*block
, int comma
,
1067 int void_context_p
, int *out_subexp
)
1069 volatile struct gdb_exception except
;
1070 struct cleanup
*old_chain
;
1071 const struct language_defn
*lang
= NULL
;
1074 lexptr
= *stringptr
;
1078 type_stack_depth
= 0;
1079 expout_last_struct
= -1;
1081 comma_terminates
= comma
;
1083 if (lexptr
== 0 || *lexptr
== 0)
1084 error_no_arg (_("expression to compute"));
1086 old_chain
= make_cleanup (free_funcalls
, 0 /*ignore*/);
1089 expression_context_block
= block
;
1091 /* If no context specified, try using the current frame, if any. */
1092 if (!expression_context_block
)
1093 expression_context_block
= get_selected_block (&expression_context_pc
);
1095 expression_context_pc
= BLOCK_START (expression_context_block
);
1097 /* Fall back to using the current source static context, if any. */
1099 if (!expression_context_block
)
1101 struct symtab_and_line cursal
= get_current_source_symtab_and_line ();
1103 expression_context_block
1104 = BLOCKVECTOR_BLOCK (BLOCKVECTOR (cursal
.symtab
), STATIC_BLOCK
);
1105 if (expression_context_block
)
1106 expression_context_pc
= BLOCK_START (expression_context_block
);
1109 if (language_mode
== language_mode_auto
&& block
!= NULL
)
1111 /* Find the language associated to the given context block.
1112 Default to the current language if it can not be determined.
1114 Note that using the language corresponding to the current frame
1115 can sometimes give unexpected results. For instance, this
1116 routine is often called several times during the inferior
1117 startup phase to re-parse breakpoint expressions after
1118 a new shared library has been loaded. The language associated
1119 to the current frame at this moment is not relevant for
1120 the breakpoint. Using it would therefore be silly, so it seems
1121 better to rely on the current language rather than relying on
1122 the current frame language to parse the expression. That's why
1123 we do the following language detection only if the context block
1124 has been specifically provided. */
1125 struct symbol
*func
= block_linkage_function (block
);
1128 lang
= language_def (SYMBOL_LANGUAGE (func
));
1129 if (lang
== NULL
|| lang
->la_language
== language_unknown
)
1130 lang
= current_language
;
1133 lang
= current_language
;
1137 expout
= (struct expression
*)
1138 xmalloc (sizeof (struct expression
) + EXP_ELEM_TO_BYTES (expout_size
));
1139 expout
->language_defn
= lang
;
1140 expout
->gdbarch
= get_current_arch ();
1142 TRY_CATCH (except
, RETURN_MASK_ALL
)
1144 if (lang
->la_parser ())
1145 lang
->la_error (NULL
);
1147 if (except
.reason
< 0)
1149 if (! in_parse_field
)
1152 throw_exception (except
);
1156 discard_cleanups (old_chain
);
1158 /* Record the actual number of expression elements, and then
1159 reallocate the expression memory so that we free up any
1162 expout
->nelts
= expout_ptr
;
1163 expout
= (struct expression
*)
1164 xrealloc ((char *) expout
,
1165 sizeof (struct expression
) + EXP_ELEM_TO_BYTES (expout_ptr
));;
1167 /* Convert expression from postfix form as generated by yacc
1168 parser, to a prefix form. */
1170 if (expressiondebug
)
1171 dump_raw_expression (expout
, gdb_stdlog
,
1172 "before conversion to prefix form");
1174 subexp
= prefixify_expression (expout
);
1176 *out_subexp
= subexp
;
1178 lang
->la_post_parser (&expout
, void_context_p
);
1180 if (expressiondebug
)
1181 dump_prefix_expression (expout
, gdb_stdlog
);
1183 *stringptr
= lexptr
;
1187 /* Parse STRING as an expression, and complain if this fails
1188 to use up all of the contents of STRING. */
1191 parse_expression (char *string
)
1193 struct expression
*exp
;
1195 exp
= parse_exp_1 (&string
, 0, 0);
1197 error (_("Junk after end of expression."));
1201 /* Parse STRING as an expression. If parsing ends in the middle of a
1202 field reference, return the type of the left-hand-side of the
1203 reference; furthermore, if the parsing ends in the field name,
1204 return the field name in *NAME. In all other cases, return NULL.
1205 Returned non-NULL *NAME must be freed by the caller. */
1208 parse_field_expression (char *string
, char **name
)
1210 struct expression
*exp
= NULL
;
1213 volatile struct gdb_exception except
;
1215 TRY_CATCH (except
, RETURN_MASK_ALL
)
1218 exp
= parse_exp_in_context (&string
, 0, 0, 0, &subexp
);
1221 if (except
.reason
< 0 || ! exp
)
1223 if (expout_last_struct
== -1)
1229 *name
= extract_field_op (exp
, &subexp
);
1235 /* (*NAME) is a part of the EXP memory block freed below. */
1236 *name
= xstrdup (*name
);
1238 val
= evaluate_subexpression_type (exp
, subexp
);
1241 return value_type (val
);
1244 /* A post-parser that does nothing */
1247 null_post_parser (struct expression
**exp
, int void_context_p
)
1251 /* Stuff for maintaining a stack of types. Currently just used by C, but
1252 probably useful for any language which declares its types "backwards". */
1255 check_type_stack_depth (void)
1257 if (type_stack_depth
== type_stack_size
)
1259 type_stack_size
*= 2;
1260 type_stack
= (union type_stack_elt
*)
1261 xrealloc ((char *) type_stack
, type_stack_size
* sizeof (*type_stack
));
1266 push_type (enum type_pieces tp
)
1268 check_type_stack_depth ();
1269 type_stack
[type_stack_depth
++].piece
= tp
;
1273 push_type_int (int n
)
1275 check_type_stack_depth ();
1276 type_stack
[type_stack_depth
++].int_val
= n
;
1280 push_type_address_space (char *string
)
1282 push_type_int (address_space_name_to_int (parse_gdbarch
, string
));
1288 if (type_stack_depth
)
1289 return type_stack
[--type_stack_depth
].piece
;
1296 if (type_stack_depth
)
1297 return type_stack
[--type_stack_depth
].int_val
;
1298 /* "Can't happen". */
1302 /* Pop the type stack and return the type which corresponds to FOLLOW_TYPE
1303 as modified by all the stuff on the stack. */
1305 follow_types (struct type
*follow_type
)
1309 int make_volatile
= 0;
1310 int make_addr_space
= 0;
1314 switch (pop_type ())
1319 follow_type
= make_cv_type (make_const
,
1320 TYPE_VOLATILE (follow_type
),
1323 follow_type
= make_cv_type (TYPE_CONST (follow_type
),
1326 if (make_addr_space
)
1327 follow_type
= make_type_with_address_space (follow_type
,
1329 make_const
= make_volatile
= 0;
1330 make_addr_space
= 0;
1338 case tp_space_identifier
:
1339 make_addr_space
= pop_type_int ();
1342 follow_type
= lookup_pointer_type (follow_type
);
1344 follow_type
= make_cv_type (make_const
,
1345 TYPE_VOLATILE (follow_type
),
1348 follow_type
= make_cv_type (TYPE_CONST (follow_type
),
1351 if (make_addr_space
)
1352 follow_type
= make_type_with_address_space (follow_type
,
1354 make_const
= make_volatile
= 0;
1355 make_addr_space
= 0;
1358 follow_type
= lookup_reference_type (follow_type
);
1360 follow_type
= make_cv_type (make_const
,
1361 TYPE_VOLATILE (follow_type
),
1364 follow_type
= make_cv_type (TYPE_CONST (follow_type
),
1367 if (make_addr_space
)
1368 follow_type
= make_type_with_address_space (follow_type
,
1370 make_const
= make_volatile
= 0;
1371 make_addr_space
= 0;
1374 array_size
= pop_type_int ();
1375 /* FIXME-type-allocation: need a way to free this type when we are
1378 lookup_array_range_type (follow_type
,
1379 0, array_size
>= 0 ? array_size
- 1 : 0);
1381 TYPE_ARRAY_UPPER_BOUND_IS_UNDEFINED (follow_type
) = 1;
1384 /* FIXME-type-allocation: need a way to free this type when we are
1386 follow_type
= lookup_function_type (follow_type
);
1392 /* This function avoids direct calls to fprintf
1393 in the parser generated debug code. */
1395 parser_fprintf (FILE *x
, const char *y
, ...)
1401 vfprintf_unfiltered (gdb_stderr
, y
, args
);
1404 fprintf_unfiltered (gdb_stderr
, " Unknown FILE used.\n");
1405 vfprintf_unfiltered (gdb_stderr
, y
, args
);
1410 /* Implementation of the exp_descriptor method operator_check. */
1413 operator_check_standard (struct expression
*exp
, int pos
,
1414 int (*objfile_func
) (struct objfile
*objfile
,
1418 const union exp_element
*const elts
= exp
->elts
;
1419 struct type
*type
= NULL
;
1420 struct objfile
*objfile
= NULL
;
1422 /* Extended operators should have been already handled by exp_descriptor
1423 iterate method of its specific language. */
1424 gdb_assert (elts
[pos
].opcode
< OP_EXTENDED0
);
1426 /* Track the callers of write_exp_elt_type for this table. */
1428 switch (elts
[pos
].opcode
)
1438 case UNOP_DYNAMIC_CAST
:
1439 case UNOP_REINTERPRET_CAST
:
1443 type
= elts
[pos
+ 1].type
;
1448 LONGEST arg
, nargs
= elts
[pos
+ 1].longconst
;
1450 for (arg
= 0; arg
< nargs
; arg
++)
1452 struct type
*type
= elts
[pos
+ 2 + arg
].type
;
1453 struct objfile
*objfile
= TYPE_OBJFILE (type
);
1455 if (objfile
&& (*objfile_func
) (objfile
, data
))
1461 case UNOP_MEMVAL_TLS
:
1462 objfile
= elts
[pos
+ 1].objfile
;
1463 type
= elts
[pos
+ 2].type
;
1468 const struct block
*const block
= elts
[pos
+ 1].block
;
1469 const struct symbol
*const symbol
= elts
[pos
+ 2].symbol
;
1471 /* Check objfile where the variable itself is placed.
1472 SYMBOL_OBJ_SECTION (symbol) may be NULL. */
1473 if ((*objfile_func
) (SYMBOL_SYMTAB (symbol
)->objfile
, data
))
1476 /* Check objfile where is placed the code touching the variable. */
1477 objfile
= lookup_objfile_from_block (block
);
1479 type
= SYMBOL_TYPE (symbol
);
1484 /* Invoke callbacks for TYPE and OBJFILE if they were set as non-NULL. */
1486 if (type
&& TYPE_OBJFILE (type
)
1487 && (*objfile_func
) (TYPE_OBJFILE (type
), data
))
1489 if (objfile
&& (*objfile_func
) (objfile
, data
))
1495 /* Call OBJFILE_FUNC for any TYPE and OBJFILE found being referenced by EXP.
1496 The functions are never called with NULL OBJFILE. Functions get passed an
1497 arbitrary caller supplied DATA pointer. If any of the functions returns
1498 non-zero value then (any other) non-zero value is immediately returned to
1499 the caller. Otherwise zero is returned after iterating through whole EXP.
1503 exp_iterate (struct expression
*exp
,
1504 int (*objfile_func
) (struct objfile
*objfile
, void *data
),
1509 for (endpos
= exp
->nelts
; endpos
> 0; )
1511 int pos
, args
, oplen
= 0;
1513 exp
->language_defn
->la_exp_desc
->operator_length (exp
, endpos
,
1515 gdb_assert (oplen
> 0);
1517 pos
= endpos
- oplen
;
1518 if (exp
->language_defn
->la_exp_desc
->operator_check (exp
, pos
,
1519 objfile_func
, data
))
1528 /* Helper for exp_uses_objfile. */
1531 exp_uses_objfile_iter (struct objfile
*exp_objfile
, void *objfile_voidp
)
1533 struct objfile
*objfile
= objfile_voidp
;
1535 if (exp_objfile
->separate_debug_objfile_backlink
)
1536 exp_objfile
= exp_objfile
->separate_debug_objfile_backlink
;
1538 return exp_objfile
== objfile
;
1541 /* Return 1 if EXP uses OBJFILE (and will become dangling when OBJFILE
1542 is unloaded), otherwise return 0. OBJFILE must not be a separate debug info
1546 exp_uses_objfile (struct expression
*exp
, struct objfile
*objfile
)
1548 gdb_assert (objfile
->separate_debug_objfile_backlink
== NULL
);
1550 return exp_iterate (exp
, exp_uses_objfile_iter
, objfile
);
1554 _initialize_parse (void)
1556 type_stack_size
= 80;
1557 type_stack_depth
= 0;
1558 type_stack
= (union type_stack_elt
*)
1559 xmalloc (type_stack_size
* sizeof (*type_stack
));
1561 add_setshow_zinteger_cmd ("expression", class_maintenance
,
1562 &expressiondebug
, _("\
1563 Set expression debugging."), _("\
1564 Show expression debugging."), _("\
1565 When non-zero, the internal representation of expressions will be printed."),
1567 show_expressiondebug
,
1568 &setdebuglist
, &showdebuglist
);
1569 add_setshow_boolean_cmd ("parser", class_maintenance
,
1571 Set parser debugging."), _("\
1572 Show parser debugging."), _("\
1573 When non-zero, expression parser tracing will be enabled."),
1576 &setdebuglist
, &showdebuglist
);