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
;
171 funcall_chain
= call
->next
;
172 arglist_len
= call
->arglist_len
;
177 /* Free everything in the funcall chain.
178 Used when there is an error inside parsing. */
181 free_funcalls (void *ignore
)
183 struct funcall
*call
, *next
;
185 for (call
= funcall_chain
; call
; call
= next
)
192 /* This page contains the functions for adding data to the struct expression
193 being constructed. */
195 /* Add one element to the end of the expression. */
197 /* To avoid a bug in the Sun 4 compiler, we pass things that can fit into
198 a register through here */
201 write_exp_elt (union exp_element expelt
)
203 if (expout_ptr
>= expout_size
)
206 expout
= (struct expression
*)
207 xrealloc ((char *) expout
, sizeof (struct expression
)
208 + EXP_ELEM_TO_BYTES (expout_size
));
210 expout
->elts
[expout_ptr
++] = expelt
;
214 write_exp_elt_opcode (enum exp_opcode expelt
)
216 union exp_element tmp
;
217 memset (&tmp
, 0, sizeof (union exp_element
));
225 write_exp_elt_sym (struct symbol
*expelt
)
227 union exp_element tmp
;
228 memset (&tmp
, 0, sizeof (union exp_element
));
236 write_exp_elt_block (struct block
*b
)
238 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
;
248 memset (&tmp
, 0, sizeof (union exp_element
));
249 tmp
.objfile
= objfile
;
254 write_exp_elt_longcst (LONGEST expelt
)
256 union exp_element tmp
;
257 memset (&tmp
, 0, sizeof (union exp_element
));
259 tmp
.longconst
= expelt
;
265 write_exp_elt_dblcst (DOUBLEST expelt
)
267 union exp_element tmp
;
268 memset (&tmp
, 0, sizeof (union exp_element
));
270 tmp
.doubleconst
= expelt
;
276 write_exp_elt_decfloatcst (gdb_byte expelt
[16])
278 union exp_element tmp
;
281 for (index
= 0; index
< 16; index
++)
282 tmp
.decfloatconst
[index
] = expelt
[index
];
288 write_exp_elt_type (struct type
*expelt
)
290 union exp_element tmp
;
291 memset (&tmp
, 0, sizeof (union exp_element
));
299 write_exp_elt_intern (struct internalvar
*expelt
)
301 union exp_element tmp
;
302 memset (&tmp
, 0, sizeof (union exp_element
));
304 tmp
.internalvar
= expelt
;
309 /* Add a string constant to the end of the expression.
311 String constants are stored by first writing an expression element
312 that contains the length of the string, then stuffing the string
313 constant itself into however many expression elements are needed
314 to hold it, and then writing another expression element that contains
315 the length of the string. I.E. an expression element at each end of
316 the string records the string length, so you can skip over the
317 expression elements containing the actual string bytes from either
318 end of the string. Note that this also allows gdb to handle
319 strings with embedded null bytes, as is required for some languages.
321 Don't be fooled by the fact that the string is null byte terminated,
322 this is strictly for the convenience of debugging gdb itself.
323 Gdb does not depend up the string being null terminated, since the
324 actual length is recorded in expression elements at each end of the
325 string. The null byte is taken into consideration when computing how
326 many expression elements are required to hold the string constant, of
331 write_exp_string (struct stoken str
)
333 int len
= str
.length
;
337 /* Compute the number of expression elements required to hold the string
338 (including a null byte terminator), along with one expression element
339 at each end to record the actual string length (not including the
340 null byte terminator). */
342 lenelt
= 2 + BYTES_TO_EXP_ELEM (len
+ 1);
344 /* Ensure that we have enough available expression elements to store
347 if ((expout_ptr
+ lenelt
) >= expout_size
)
349 expout_size
= max (expout_size
* 2, expout_ptr
+ lenelt
+ 10);
350 expout
= (struct expression
*)
351 xrealloc ((char *) expout
, (sizeof (struct expression
)
352 + EXP_ELEM_TO_BYTES (expout_size
)));
355 /* Write the leading length expression element (which advances the current
356 expression element index), then write the string constant followed by a
357 terminating null byte, and then write the trailing length expression
360 write_exp_elt_longcst ((LONGEST
) len
);
361 strdata
= (char *) &expout
->elts
[expout_ptr
];
362 memcpy (strdata
, str
.ptr
, len
);
363 *(strdata
+ len
) = '\0';
364 expout_ptr
+= lenelt
- 2;
365 write_exp_elt_longcst ((LONGEST
) len
);
368 /* Add a vector of string constants to the end of the expression.
370 This adds an OP_STRING operation, but encodes the contents
371 differently from write_exp_string. The language is expected to
372 handle evaluation of this expression itself.
374 After the usual OP_STRING header, TYPE is written into the
375 expression as a long constant. The interpretation of this field is
376 up to the language evaluator.
378 Next, each string in VEC is written. The length is written as a
379 long constant, followed by the contents of the string. */
382 write_exp_string_vector (int type
, struct stoken_vector
*vec
)
386 /* Compute the size. We compute the size in number of slots to
387 avoid issues with string padding. */
389 for (i
= 0; i
< vec
->len
; ++i
)
391 /* One slot for the length of this element, plus the number of
392 slots needed for this string. */
393 n_slots
+= 1 + BYTES_TO_EXP_ELEM (vec
->tokens
[i
].length
);
396 /* One more slot for the type of the string. */
399 /* Now compute a phony string length. */
400 len
= EXP_ELEM_TO_BYTES (n_slots
) - 1;
403 if ((expout_ptr
+ n_slots
) >= expout_size
)
405 expout_size
= max (expout_size
* 2, expout_ptr
+ n_slots
+ 10);
406 expout
= (struct expression
*)
407 xrealloc ((char *) expout
, (sizeof (struct expression
)
408 + EXP_ELEM_TO_BYTES (expout_size
)));
411 write_exp_elt_opcode (OP_STRING
);
412 write_exp_elt_longcst (len
);
413 write_exp_elt_longcst (type
);
415 for (i
= 0; i
< vec
->len
; ++i
)
417 write_exp_elt_longcst (vec
->tokens
[i
].length
);
418 memcpy (&expout
->elts
[expout_ptr
], vec
->tokens
[i
].ptr
,
419 vec
->tokens
[i
].length
);
420 expout_ptr
+= BYTES_TO_EXP_ELEM (vec
->tokens
[i
].length
);
423 write_exp_elt_longcst (len
);
424 write_exp_elt_opcode (OP_STRING
);
427 /* Add a bitstring constant to the end of the expression.
429 Bitstring constants are stored by first writing an expression element
430 that contains the length of the bitstring (in bits), then stuffing the
431 bitstring constant itself into however many expression elements are
432 needed to hold it, and then writing another expression element that
433 contains the length of the bitstring. I.E. an expression element at
434 each end of the bitstring records the bitstring length, so you can skip
435 over the expression elements containing the actual bitstring bytes from
436 either end of the bitstring. */
439 write_exp_bitstring (struct stoken str
)
441 int bits
= str
.length
; /* length in bits */
442 int len
= (bits
+ HOST_CHAR_BIT
- 1) / HOST_CHAR_BIT
;
446 /* Compute the number of expression elements required to hold the bitstring,
447 along with one expression element at each end to record the actual
448 bitstring length in bits. */
450 lenelt
= 2 + BYTES_TO_EXP_ELEM (len
);
452 /* Ensure that we have enough available expression elements to store
455 if ((expout_ptr
+ lenelt
) >= expout_size
)
457 expout_size
= max (expout_size
* 2, expout_ptr
+ lenelt
+ 10);
458 expout
= (struct expression
*)
459 xrealloc ((char *) expout
, (sizeof (struct expression
)
460 + EXP_ELEM_TO_BYTES (expout_size
)));
463 /* Write the leading length expression element (which advances the current
464 expression element index), then write the bitstring constant, and then
465 write the trailing length expression element. */
467 write_exp_elt_longcst ((LONGEST
) bits
);
468 strdata
= (char *) &expout
->elts
[expout_ptr
];
469 memcpy (strdata
, str
.ptr
, len
);
470 expout_ptr
+= lenelt
- 2;
471 write_exp_elt_longcst ((LONGEST
) bits
);
474 /* Add the appropriate elements for a minimal symbol to the end of
478 write_exp_msymbol (struct minimal_symbol
*msymbol
)
480 struct objfile
*objfile
= msymbol_objfile (msymbol
);
481 struct gdbarch
*gdbarch
= get_objfile_arch (objfile
);
483 CORE_ADDR addr
= SYMBOL_VALUE_ADDRESS (msymbol
);
484 struct obj_section
*section
= SYMBOL_OBJ_SECTION (msymbol
);
485 enum minimal_symbol_type type
= MSYMBOL_TYPE (msymbol
);
488 /* The minimal symbol might point to a function descriptor;
489 resolve it to the actual code address instead. */
490 pc
= gdbarch_convert_from_func_ptr_addr (gdbarch
, addr
, ¤t_target
);
493 /* In this case, assume we have a code symbol instead of
500 if (overlay_debugging
)
501 addr
= symbol_overlayed_address (addr
, section
);
503 write_exp_elt_opcode (OP_LONG
);
504 /* Let's make the type big enough to hold a 64-bit address. */
505 write_exp_elt_type (objfile_type (objfile
)->builtin_core_addr
);
506 write_exp_elt_longcst ((LONGEST
) addr
);
507 write_exp_elt_opcode (OP_LONG
);
509 if (section
&& section
->the_bfd_section
->flags
& SEC_THREAD_LOCAL
)
511 write_exp_elt_opcode (UNOP_MEMVAL_TLS
);
512 write_exp_elt_objfile (objfile
);
513 write_exp_elt_type (objfile_type (objfile
)->nodebug_tls_symbol
);
514 write_exp_elt_opcode (UNOP_MEMVAL_TLS
);
518 write_exp_elt_opcode (UNOP_MEMVAL
);
523 case mst_solib_trampoline
:
524 write_exp_elt_type (objfile_type (objfile
)->nodebug_text_symbol
);
531 write_exp_elt_type (objfile_type (objfile
)->nodebug_data_symbol
);
535 write_exp_elt_type (objfile_type (objfile
)->nodebug_unknown_symbol
);
538 write_exp_elt_opcode (UNOP_MEMVAL
);
541 /* Mark the current index as the starting location of a structure
542 expression. This is used when completing on field names. */
545 mark_struct_expression (void)
547 expout_last_struct
= expout_ptr
;
551 /* Recognize tokens that start with '$'. These include:
553 $regname A native register name or a "standard
556 $variable A convenience variable with a name chosen
559 $digits Value history with index <digits>, starting
560 from the first value which has index 1.
562 $$digits Value history with index <digits> relative
563 to the last value. I.E. $$0 is the last
564 value, $$1 is the one previous to that, $$2
565 is the one previous to $$1, etc.
567 $ | $0 | $$0 The last value in the value history.
569 $$ An abbreviation for the second to the last
570 value in the value history, I.E. $$1
575 write_dollar_variable (struct stoken str
)
577 struct symbol
*sym
= NULL
;
578 struct minimal_symbol
*msym
= NULL
;
579 struct internalvar
*isym
= NULL
;
581 /* Handle the tokens $digits; also $ (short for $0) and $$ (short for $$1)
582 and $$digits (equivalent to $<-digits> if you could type that). */
586 /* Double dollar means negate the number and add -1 as well.
587 Thus $$ alone means -1. */
588 if (str
.length
>= 2 && str
.ptr
[1] == '$')
595 /* Just dollars (one or two) */
599 /* Is the rest of the token digits? */
600 for (; i
< str
.length
; i
++)
601 if (!(str
.ptr
[i
] >= '0' && str
.ptr
[i
] <= '9'))
605 i
= atoi (str
.ptr
+ 1 + negate
);
611 /* Handle tokens that refer to machine registers:
612 $ followed by a register name. */
613 i
= user_reg_map_name_to_regnum (parse_gdbarch
,
614 str
.ptr
+ 1, str
.length
- 1);
616 goto handle_register
;
618 /* Any names starting with $ are probably debugger internal variables. */
620 isym
= lookup_only_internalvar (copy_name (str
) + 1);
623 write_exp_elt_opcode (OP_INTERNALVAR
);
624 write_exp_elt_intern (isym
);
625 write_exp_elt_opcode (OP_INTERNALVAR
);
629 /* On some systems, such as HP-UX and hppa-linux, certain system routines
630 have names beginning with $ or $$. Check for those, first. */
632 sym
= lookup_symbol (copy_name (str
), (struct block
*) NULL
,
633 VAR_DOMAIN
, (int *) NULL
);
636 write_exp_elt_opcode (OP_VAR_VALUE
);
637 write_exp_elt_block (block_found
); /* set by lookup_symbol */
638 write_exp_elt_sym (sym
);
639 write_exp_elt_opcode (OP_VAR_VALUE
);
642 msym
= lookup_minimal_symbol (copy_name (str
), NULL
, NULL
);
645 write_exp_msymbol (msym
);
649 /* Any other names are assumed to be debugger internal variables. */
651 write_exp_elt_opcode (OP_INTERNALVAR
);
652 write_exp_elt_intern (create_internalvar (copy_name (str
) + 1));
653 write_exp_elt_opcode (OP_INTERNALVAR
);
656 write_exp_elt_opcode (OP_LAST
);
657 write_exp_elt_longcst ((LONGEST
) i
);
658 write_exp_elt_opcode (OP_LAST
);
661 write_exp_elt_opcode (OP_REGISTER
);
664 write_exp_string (str
);
665 write_exp_elt_opcode (OP_REGISTER
);
671 find_template_name_end (char *p
)
674 int just_seen_right
= 0;
675 int just_seen_colon
= 0;
676 int just_seen_space
= 0;
678 if (!p
|| (*p
!= '<'))
689 /* In future, may want to allow these?? */
692 depth
++; /* start nested template */
693 if (just_seen_colon
|| just_seen_right
|| just_seen_space
)
694 return 0; /* but not after : or :: or > or space */
697 if (just_seen_colon
|| just_seen_right
)
698 return 0; /* end a (nested?) template */
699 just_seen_right
= 1; /* but not after : or :: */
700 if (--depth
== 0) /* also disallow >>, insist on > > */
701 return ++p
; /* if outermost ended, return */
704 if (just_seen_space
|| (just_seen_colon
> 1))
705 return 0; /* nested class spec coming up */
706 just_seen_colon
++; /* we allow :: but not :::: */
711 if (!((*p
>= 'a' && *p
<= 'z') || /* allow token chars */
712 (*p
>= 'A' && *p
<= 'Z') ||
713 (*p
>= '0' && *p
<= '9') ||
714 (*p
== '_') || (*p
== ',') || /* commas for template args */
715 (*p
== '&') || (*p
== '*') || /* pointer and ref types */
716 (*p
== '(') || (*p
== ')') || /* function types */
717 (*p
== '[') || (*p
== ']'))) /* array types */
732 /* Return a null-terminated temporary copy of the name
733 of a string token. */
736 copy_name (struct stoken token
)
738 /* Make sure there's enough space for the token. */
739 if (namecopy_size
< token
.length
+ 1)
741 namecopy_size
= token
.length
+ 1;
742 namecopy
= xrealloc (namecopy
, token
.length
+ 1);
745 memcpy (namecopy
, token
.ptr
, token
.length
);
746 namecopy
[token
.length
] = 0;
751 /* Reverse an expression from suffix form (in which it is constructed)
752 to prefix form (in which we can conveniently print or execute it).
753 Ordinarily this always returns -1. However, if EXPOUT_LAST_STRUCT
754 is not -1 (i.e., we are trying to complete a field name), it will
755 return the index of the subexpression which is the left-hand-side
756 of the struct operation at EXPOUT_LAST_STRUCT. */
759 prefixify_expression (struct expression
*expr
)
761 int len
= sizeof (struct expression
) + EXP_ELEM_TO_BYTES (expr
->nelts
);
762 struct expression
*temp
;
763 int inpos
= expr
->nelts
, outpos
= 0;
765 temp
= (struct expression
*) alloca (len
);
767 /* Copy the original expression into temp. */
768 memcpy (temp
, expr
, len
);
770 return prefixify_subexp (temp
, expr
, inpos
, outpos
);
773 /* Return the number of exp_elements in the postfix subexpression
774 of EXPR whose operator is at index ENDPOS - 1 in EXPR. */
777 length_of_subexp (struct expression
*expr
, int endpos
)
781 operator_length (expr
, endpos
, &oplen
, &args
);
785 oplen
+= length_of_subexp (expr
, endpos
- oplen
);
792 /* Sets *OPLENP to the length of the operator whose (last) index is
793 ENDPOS - 1 in EXPR, and sets *ARGSP to the number of arguments that
797 operator_length (struct expression
*expr
, int endpos
, int *oplenp
, int *argsp
)
799 expr
->language_defn
->la_exp_desc
->operator_length (expr
, endpos
,
803 /* Default value for operator_length in exp_descriptor vectors. */
806 operator_length_standard (struct expression
*expr
, int endpos
,
807 int *oplenp
, int *argsp
)
811 enum f90_range_type range_type
;
815 error (_("?error in operator_length_standard"));
817 i
= (int) expr
->elts
[endpos
- 1].opcode
;
823 oplen
= longest_to_int (expr
->elts
[endpos
- 2].longconst
);
824 oplen
= 5 + BYTES_TO_EXP_ELEM (oplen
+ 1);
847 case OP_F77_UNDETERMINED_ARGLIST
:
849 args
= 1 + longest_to_int (expr
->elts
[endpos
- 2].longconst
);
853 oplen
= 4 + longest_to_int (expr
->elts
[endpos
- 2].longconst
);
857 case OP_OBJC_MSGCALL
: /* Objective C message (method) call */
859 args
= 1 + longest_to_int (expr
->elts
[endpos
- 2].longconst
);
869 case UNOP_DYNAMIC_CAST
:
870 case UNOP_REINTERPRET_CAST
:
876 case UNOP_MEMVAL_TLS
:
894 oplen
= longest_to_int (expr
->elts
[endpos
- 2].longconst
);
895 oplen
= 4 + BYTES_TO_EXP_ELEM (oplen
+ 1);
901 case STRUCTOP_STRUCT
:
908 case OP_OBJC_NSSTRING
: /* Objective C Foundation Class NSString constant */
909 case OP_OBJC_SELECTOR
: /* Objective C "@selector" pseudo-op */
911 oplen
= longest_to_int (expr
->elts
[endpos
- 2].longconst
);
912 oplen
= 4 + BYTES_TO_EXP_ELEM (oplen
+ 1);
916 oplen
= longest_to_int (expr
->elts
[endpos
- 2].longconst
);
917 oplen
= (oplen
+ HOST_CHAR_BIT
- 1) / HOST_CHAR_BIT
;
918 oplen
= 4 + BYTES_TO_EXP_ELEM (oplen
);
923 args
= longest_to_int (expr
->elts
[endpos
- 2].longconst
);
924 args
-= longest_to_int (expr
->elts
[endpos
- 3].longconst
);
930 case TERNOP_SLICE_COUNT
:
935 case MULTI_SUBSCRIPT
:
937 args
= 1 + longest_to_int (expr
->elts
[endpos
- 2].longconst
);
940 case BINOP_ASSIGN_MODIFY
:
954 range_type
= longest_to_int (expr
->elts
[endpos
- 2].longconst
);
957 case LOW_BOUND_DEFAULT
:
958 case HIGH_BOUND_DEFAULT
:
961 case BOTH_BOUND_DEFAULT
:
964 case NONE_BOUND_DEFAULT
:
972 args
= 1 + (i
< (int) BINOP_END
);
979 /* Copy the subexpression ending just before index INEND in INEXPR
980 into OUTEXPR, starting at index OUTBEG.
981 In the process, convert it from suffix to prefix form.
982 If EXPOUT_LAST_STRUCT is -1, then this function always returns -1.
983 Otherwise, it returns the index of the subexpression which is the
984 left-hand-side of the expression at EXPOUT_LAST_STRUCT. */
987 prefixify_subexp (struct expression
*inexpr
,
988 struct expression
*outexpr
, int inend
, int outbeg
)
996 operator_length (inexpr
, inend
, &oplen
, &args
);
998 /* Copy the final operator itself, from the end of the input
999 to the beginning of the output. */
1001 memcpy (&outexpr
->elts
[outbeg
], &inexpr
->elts
[inend
],
1002 EXP_ELEM_TO_BYTES (oplen
));
1005 if (expout_last_struct
== inend
)
1006 result
= outbeg
- oplen
;
1008 /* Find the lengths of the arg subexpressions. */
1009 arglens
= (int *) alloca (args
* sizeof (int));
1010 for (i
= args
- 1; i
>= 0; i
--)
1012 oplen
= length_of_subexp (inexpr
, inend
);
1017 /* Now copy each subexpression, preserving the order of
1018 the subexpressions, but prefixifying each one.
1019 In this loop, inend starts at the beginning of
1020 the expression this level is working on
1021 and marches forward over the arguments.
1022 outbeg does similarly in the output. */
1023 for (i
= 0; i
< args
; i
++)
1028 r
= prefixify_subexp (inexpr
, outexpr
, inend
, outbeg
);
1031 /* Return immediately. We probably have only parsed a
1032 partial expression, so we don't want to try to reverse
1033 the other operands. */
1042 /* This page contains the two entry points to this file. */
1044 /* Read an expression from the string *STRINGPTR points to,
1045 parse it, and return a pointer to a struct expression that we malloc.
1046 Use block BLOCK as the lexical context for variable names;
1047 if BLOCK is zero, use the block of the selected stack frame.
1048 Meanwhile, advance *STRINGPTR to point after the expression,
1049 at the first nonwhite character that is not part of the expression
1050 (possibly a null character).
1052 If COMMA is nonzero, stop if a comma is reached. */
1055 parse_exp_1 (char **stringptr
, struct block
*block
, int comma
)
1057 return parse_exp_in_context (stringptr
, block
, comma
, 0, NULL
);
1060 /* As for parse_exp_1, except that if VOID_CONTEXT_P, then
1061 no value is expected from the expression.
1062 OUT_SUBEXP is set when attempting to complete a field name; in this
1063 case it is set to the index of the subexpression on the
1064 left-hand-side of the struct op. If not doing such completion, it
1065 is left untouched. */
1067 static struct expression
*
1068 parse_exp_in_context (char **stringptr
, struct block
*block
, int comma
,
1069 int void_context_p
, int *out_subexp
)
1071 volatile struct gdb_exception except
;
1072 struct cleanup
*old_chain
;
1075 lexptr
= *stringptr
;
1079 type_stack_depth
= 0;
1080 expout_last_struct
= -1;
1082 comma_terminates
= comma
;
1084 if (lexptr
== 0 || *lexptr
== 0)
1085 error_no_arg (_("expression to compute"));
1087 old_chain
= make_cleanup (free_funcalls
, 0 /*ignore*/);
1090 expression_context_block
= block
;
1092 /* If no context specified, try using the current frame, if any. */
1093 if (!expression_context_block
)
1094 expression_context_block
= get_selected_block (&expression_context_pc
);
1096 expression_context_pc
= BLOCK_START (expression_context_block
);
1098 /* Fall back to using the current source static context, if any. */
1100 if (!expression_context_block
)
1102 struct symtab_and_line cursal
= get_current_source_symtab_and_line ();
1104 expression_context_block
1105 = BLOCKVECTOR_BLOCK (BLOCKVECTOR (cursal
.symtab
), STATIC_BLOCK
);
1106 if (expression_context_block
)
1107 expression_context_pc
= BLOCK_START (expression_context_block
);
1112 expout
= (struct expression
*)
1113 xmalloc (sizeof (struct expression
) + EXP_ELEM_TO_BYTES (expout_size
));
1114 expout
->language_defn
= current_language
;
1115 expout
->gdbarch
= get_current_arch ();
1117 TRY_CATCH (except
, RETURN_MASK_ALL
)
1119 if (current_language
->la_parser ())
1120 current_language
->la_error (NULL
);
1122 if (except
.reason
< 0)
1124 if (! in_parse_field
)
1127 throw_exception (except
);
1131 discard_cleanups (old_chain
);
1133 /* Record the actual number of expression elements, and then
1134 reallocate the expression memory so that we free up any
1137 expout
->nelts
= expout_ptr
;
1138 expout
= (struct expression
*)
1139 xrealloc ((char *) expout
,
1140 sizeof (struct expression
) + EXP_ELEM_TO_BYTES (expout_ptr
));;
1142 /* Convert expression from postfix form as generated by yacc
1143 parser, to a prefix form. */
1145 if (expressiondebug
)
1146 dump_raw_expression (expout
, gdb_stdlog
,
1147 "before conversion to prefix form");
1149 subexp
= prefixify_expression (expout
);
1151 *out_subexp
= subexp
;
1153 current_language
->la_post_parser (&expout
, void_context_p
);
1155 if (expressiondebug
)
1156 dump_prefix_expression (expout
, gdb_stdlog
);
1158 *stringptr
= lexptr
;
1162 /* Parse STRING as an expression, and complain if this fails
1163 to use up all of the contents of STRING. */
1166 parse_expression (char *string
)
1168 struct expression
*exp
;
1169 exp
= parse_exp_1 (&string
, 0, 0);
1171 error (_("Junk after end of expression."));
1175 /* Parse STRING as an expression. If parsing ends in the middle of a
1176 field reference, return the type of the left-hand-side of the
1177 reference; furthermore, if the parsing ends in the field name,
1178 return the field name in *NAME. In all other cases, return NULL.
1179 Returned non-NULL *NAME must be freed by the caller. */
1182 parse_field_expression (char *string
, char **name
)
1184 struct expression
*exp
= NULL
;
1187 volatile struct gdb_exception except
;
1189 TRY_CATCH (except
, RETURN_MASK_ALL
)
1192 exp
= parse_exp_in_context (&string
, 0, 0, 0, &subexp
);
1195 if (except
.reason
< 0 || ! exp
)
1197 if (expout_last_struct
== -1)
1203 *name
= extract_field_op (exp
, &subexp
);
1209 /* (*NAME) is a part of the EXP memory block freed below. */
1210 *name
= xstrdup (*name
);
1212 val
= evaluate_subexpression_type (exp
, subexp
);
1215 return value_type (val
);
1218 /* A post-parser that does nothing */
1221 null_post_parser (struct expression
**exp
, int void_context_p
)
1225 /* Stuff for maintaining a stack of types. Currently just used by C, but
1226 probably useful for any language which declares its types "backwards". */
1229 check_type_stack_depth (void)
1231 if (type_stack_depth
== type_stack_size
)
1233 type_stack_size
*= 2;
1234 type_stack
= (union type_stack_elt
*)
1235 xrealloc ((char *) type_stack
, type_stack_size
* sizeof (*type_stack
));
1240 push_type (enum type_pieces tp
)
1242 check_type_stack_depth ();
1243 type_stack
[type_stack_depth
++].piece
= tp
;
1247 push_type_int (int n
)
1249 check_type_stack_depth ();
1250 type_stack
[type_stack_depth
++].int_val
= n
;
1254 push_type_address_space (char *string
)
1256 push_type_int (address_space_name_to_int (parse_gdbarch
, string
));
1262 if (type_stack_depth
)
1263 return type_stack
[--type_stack_depth
].piece
;
1270 if (type_stack_depth
)
1271 return type_stack
[--type_stack_depth
].int_val
;
1272 /* "Can't happen". */
1276 /* Pop the type stack and return the type which corresponds to FOLLOW_TYPE
1277 as modified by all the stuff on the stack. */
1279 follow_types (struct type
*follow_type
)
1283 int make_volatile
= 0;
1284 int make_addr_space
= 0;
1288 switch (pop_type ())
1293 follow_type
= make_cv_type (make_const
,
1294 TYPE_VOLATILE (follow_type
),
1297 follow_type
= make_cv_type (TYPE_CONST (follow_type
),
1300 if (make_addr_space
)
1301 follow_type
= make_type_with_address_space (follow_type
,
1303 make_const
= make_volatile
= 0;
1304 make_addr_space
= 0;
1312 case tp_space_identifier
:
1313 make_addr_space
= pop_type_int ();
1316 follow_type
= lookup_pointer_type (follow_type
);
1318 follow_type
= make_cv_type (make_const
,
1319 TYPE_VOLATILE (follow_type
),
1322 follow_type
= make_cv_type (TYPE_CONST (follow_type
),
1325 if (make_addr_space
)
1326 follow_type
= make_type_with_address_space (follow_type
,
1328 make_const
= make_volatile
= 0;
1329 make_addr_space
= 0;
1332 follow_type
= lookup_reference_type (follow_type
);
1334 follow_type
= make_cv_type (make_const
,
1335 TYPE_VOLATILE (follow_type
),
1338 follow_type
= make_cv_type (TYPE_CONST (follow_type
),
1341 if (make_addr_space
)
1342 follow_type
= make_type_with_address_space (follow_type
,
1344 make_const
= make_volatile
= 0;
1345 make_addr_space
= 0;
1348 array_size
= pop_type_int ();
1349 /* FIXME-type-allocation: need a way to free this type when we are
1352 lookup_array_range_type (follow_type
,
1353 0, array_size
>= 0 ? array_size
- 1 : 0);
1355 TYPE_ARRAY_UPPER_BOUND_IS_UNDEFINED (follow_type
) = 1;
1358 /* FIXME-type-allocation: need a way to free this type when we are
1360 follow_type
= lookup_function_type (follow_type
);
1366 /* This function avoids direct calls to fprintf
1367 in the parser generated debug code. */
1369 parser_fprintf (FILE *x
, const char *y
, ...)
1374 vfprintf_unfiltered (gdb_stderr
, y
, args
);
1377 fprintf_unfiltered (gdb_stderr
, " Unknown FILE used.\n");
1378 vfprintf_unfiltered (gdb_stderr
, y
, args
);
1383 /* Implementation of the exp_descriptor method operator_check. */
1386 operator_check_standard (struct expression
*exp
, int pos
,
1387 int (*objfile_func
) (struct objfile
*objfile
,
1391 const union exp_element
*const elts
= exp
->elts
;
1392 struct type
*type
= NULL
;
1393 struct objfile
*objfile
= NULL
;
1395 /* Extended operators should have been already handled by exp_descriptor
1396 iterate method of its specific language. */
1397 gdb_assert (elts
[pos
].opcode
< OP_EXTENDED0
);
1399 /* Track the callers of write_exp_elt_type for this table. */
1401 switch (elts
[pos
].opcode
)
1411 case UNOP_DYNAMIC_CAST
:
1412 case UNOP_REINTERPRET_CAST
:
1416 type
= elts
[pos
+ 1].type
;
1421 LONGEST arg
, nargs
= elts
[pos
+ 1].longconst
;
1423 for (arg
= 0; arg
< nargs
; arg
++)
1425 struct type
*type
= elts
[pos
+ 2 + arg
].type
;
1426 struct objfile
*objfile
= TYPE_OBJFILE (type
);
1428 if (objfile
&& (*objfile_func
) (objfile
, data
))
1434 case UNOP_MEMVAL_TLS
:
1435 objfile
= elts
[pos
+ 1].objfile
;
1436 type
= elts
[pos
+ 2].type
;
1441 const struct block
*const block
= elts
[pos
+ 1].block
;
1442 const struct symbol
*const symbol
= elts
[pos
+ 2].symbol
;
1444 /* Check objfile where the variable itself is placed.
1445 SYMBOL_OBJ_SECTION (symbol) may be NULL. */
1446 if ((*objfile_func
) (SYMBOL_SYMTAB (symbol
)->objfile
, data
))
1449 /* Check objfile where is placed the code touching the variable. */
1450 objfile
= lookup_objfile_from_block (block
);
1452 type
= SYMBOL_TYPE (symbol
);
1457 /* Invoke callbacks for TYPE and OBJFILE if they were set as non-NULL. */
1459 if (type
&& TYPE_OBJFILE (type
)
1460 && (*objfile_func
) (TYPE_OBJFILE (type
), data
))
1462 if (objfile
&& (*objfile_func
) (objfile
, data
))
1468 /* Call OBJFILE_FUNC for any TYPE and OBJFILE found being referenced by EXP.
1469 The functions are never called with NULL OBJFILE. Functions get passed an
1470 arbitrary caller supplied DATA pointer. If any of the functions returns
1471 non-zero value then (any other) non-zero value is immediately returned to
1472 the caller. Otherwise zero is returned after iterating through whole EXP.
1476 exp_iterate (struct expression
*exp
,
1477 int (*objfile_func
) (struct objfile
*objfile
, void *data
),
1482 for (endpos
= exp
->nelts
; endpos
> 0; )
1484 int pos
, args
, oplen
= 0;
1486 exp
->language_defn
->la_exp_desc
->operator_length (exp
, endpos
,
1488 gdb_assert (oplen
> 0);
1490 pos
= endpos
- oplen
;
1491 if (exp
->language_defn
->la_exp_desc
->operator_check (exp
, pos
,
1492 objfile_func
, data
))
1501 /* Helper for exp_uses_objfile. */
1504 exp_uses_objfile_iter (struct objfile
*exp_objfile
, void *objfile_voidp
)
1506 struct objfile
*objfile
= objfile_voidp
;
1508 if (exp_objfile
->separate_debug_objfile_backlink
)
1509 exp_objfile
= exp_objfile
->separate_debug_objfile_backlink
;
1511 return exp_objfile
== objfile
;
1514 /* Return 1 if EXP uses OBJFILE (and will become dangling when OBJFILE
1515 is unloaded), otherwise return 0. OBJFILE must not be a separate debug info
1519 exp_uses_objfile (struct expression
*exp
, struct objfile
*objfile
)
1521 gdb_assert (objfile
->separate_debug_objfile_backlink
== NULL
);
1523 return exp_iterate (exp
, exp_uses_objfile_iter
, objfile
);
1527 _initialize_parse (void)
1529 type_stack_size
= 80;
1530 type_stack_depth
= 0;
1531 type_stack
= (union type_stack_elt
*)
1532 xmalloc (type_stack_size
* sizeof (*type_stack
));
1534 add_setshow_zinteger_cmd ("expression", class_maintenance
,
1535 &expressiondebug
, _("\
1536 Set expression debugging."), _("\
1537 Show expression debugging."), _("\
1538 When non-zero, the internal representation of expressions will be printed."),
1540 show_expressiondebug
,
1541 &setdebuglist
, &showdebuglist
);
1542 add_setshow_boolean_cmd ("parser", class_maintenance
,
1544 Set parser debugging."), _("\
1545 Show parser debugging."), _("\
1546 When non-zero, expression parser tracing will be enabled."),
1549 &setdebuglist
, &showdebuglist
);