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
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. */
37 #include "arch-utils.h"
38 #include "gdb_string.h"
42 #include "expression.h"
47 #include "parser-defs.h"
49 #include "symfile.h" /* for overlay functions */
52 #include "gdb_assert.h"
56 #include "exceptions.h"
57 #include "user-regs.h"
59 /* Standard set of definitions for printing, dumping, prefixifying,
60 * and evaluating expressions. */
62 const struct exp_descriptor exp_descriptor_standard
=
64 print_subexp_standard
,
65 operator_length_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
);
113 static void free_funcalls (void *ignore
);
115 static int prefixify_expression (struct expression
*);
117 static int prefixify_subexp (struct expression
*, struct expression
*, int,
120 static struct expression
*parse_exp_in_context (char **, struct block
*, int,
123 void _initialize_parse (void);
125 /* Data structure for saving values of arglist_len for function calls whose
126 arguments contain other function calls. */
130 struct funcall
*next
;
134 static struct funcall
*funcall_chain
;
136 /* Begin counting arguments for a function call,
137 saving the data about any containing call. */
144 new = (struct funcall
*) xmalloc (sizeof (struct funcall
));
145 new->next
= funcall_chain
;
146 new->arglist_len
= arglist_len
;
151 /* Return the number of arguments in a function call just terminated,
152 and restore the data for the containing function call. */
157 int val
= arglist_len
;
158 struct funcall
*call
= funcall_chain
;
159 funcall_chain
= call
->next
;
160 arglist_len
= call
->arglist_len
;
165 /* Free everything in the funcall chain.
166 Used when there is an error inside parsing. */
169 free_funcalls (void *ignore
)
171 struct funcall
*call
, *next
;
173 for (call
= funcall_chain
; call
; call
= next
)
180 /* This page contains the functions for adding data to the struct expression
181 being constructed. */
183 /* Add one element to the end of the expression. */
185 /* To avoid a bug in the Sun 4 compiler, we pass things that can fit into
186 a register through here */
189 write_exp_elt (union exp_element expelt
)
191 if (expout_ptr
>= expout_size
)
194 expout
= (struct expression
*)
195 xrealloc ((char *) expout
, sizeof (struct expression
)
196 + EXP_ELEM_TO_BYTES (expout_size
));
198 expout
->elts
[expout_ptr
++] = expelt
;
202 write_exp_elt_opcode (enum exp_opcode expelt
)
204 union exp_element tmp
;
205 memset (&tmp
, 0, sizeof (union exp_element
));
213 write_exp_elt_sym (struct symbol
*expelt
)
215 union exp_element tmp
;
216 memset (&tmp
, 0, sizeof (union exp_element
));
224 write_exp_elt_block (struct block
*b
)
226 union exp_element tmp
;
227 memset (&tmp
, 0, sizeof (union exp_element
));
233 write_exp_elt_objfile (struct objfile
*objfile
)
235 union exp_element tmp
;
236 memset (&tmp
, 0, sizeof (union exp_element
));
237 tmp
.objfile
= objfile
;
242 write_exp_elt_longcst (LONGEST expelt
)
244 union exp_element tmp
;
245 memset (&tmp
, 0, sizeof (union exp_element
));
247 tmp
.longconst
= expelt
;
253 write_exp_elt_dblcst (DOUBLEST expelt
)
255 union exp_element tmp
;
256 memset (&tmp
, 0, sizeof (union exp_element
));
258 tmp
.doubleconst
= expelt
;
264 write_exp_elt_decfloatcst (gdb_byte expelt
[16])
266 union exp_element tmp
;
269 for (index
= 0; index
< 16; index
++)
270 tmp
.decfloatconst
[index
] = expelt
[index
];
276 write_exp_elt_type (struct type
*expelt
)
278 union exp_element tmp
;
279 memset (&tmp
, 0, sizeof (union exp_element
));
287 write_exp_elt_intern (struct internalvar
*expelt
)
289 union exp_element tmp
;
290 memset (&tmp
, 0, sizeof (union exp_element
));
292 tmp
.internalvar
= expelt
;
297 /* Add a string constant to the end of the expression.
299 String constants are stored by first writing an expression element
300 that contains the length of the string, then stuffing the string
301 constant itself into however many expression elements are needed
302 to hold it, and then writing another expression element that contains
303 the length of the string. I.E. an expression element at each end of
304 the string records the string length, so you can skip over the
305 expression elements containing the actual string bytes from either
306 end of the string. Note that this also allows gdb to handle
307 strings with embedded null bytes, as is required for some languages.
309 Don't be fooled by the fact that the string is null byte terminated,
310 this is strictly for the convenience of debugging gdb itself.
311 Gdb does not depend up the string being null terminated, since the
312 actual length is recorded in expression elements at each end of the
313 string. The null byte is taken into consideration when computing how
314 many expression elements are required to hold the string constant, of
319 write_exp_string (struct stoken str
)
321 int len
= str
.length
;
325 /* Compute the number of expression elements required to hold the string
326 (including a null byte terminator), along with one expression element
327 at each end to record the actual string length (not including the
328 null byte terminator). */
330 lenelt
= 2 + BYTES_TO_EXP_ELEM (len
+ 1);
332 /* Ensure that we have enough available expression elements to store
335 if ((expout_ptr
+ lenelt
) >= expout_size
)
337 expout_size
= max (expout_size
* 2, expout_ptr
+ lenelt
+ 10);
338 expout
= (struct expression
*)
339 xrealloc ((char *) expout
, (sizeof (struct expression
)
340 + EXP_ELEM_TO_BYTES (expout_size
)));
343 /* Write the leading length expression element (which advances the current
344 expression element index), then write the string constant followed by a
345 terminating null byte, and then write the trailing length expression
348 write_exp_elt_longcst ((LONGEST
) len
);
349 strdata
= (char *) &expout
->elts
[expout_ptr
];
350 memcpy (strdata
, str
.ptr
, len
);
351 *(strdata
+ len
) = '\0';
352 expout_ptr
+= lenelt
- 2;
353 write_exp_elt_longcst ((LONGEST
) len
);
356 /* Add a vector of string constants to the end of the expression.
358 This adds an OP_STRING operation, but encodes the contents
359 differently from write_exp_string. The language is expected to
360 handle evaluation of this expression itself.
362 After the usual OP_STRING header, TYPE is written into the
363 expression as a long constant. The interpretation of this field is
364 up to the language evaluator.
366 Next, each string in VEC is written. The length is written as a
367 long constant, followed by the contents of the string. */
370 write_exp_string_vector (int type
, 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 if ((expout_ptr
+ n_slots
) >= expout_size
)
393 expout_size
= max (expout_size
* 2, expout_ptr
+ n_slots
+ 10);
394 expout
= (struct expression
*)
395 xrealloc ((char *) expout
, (sizeof (struct expression
)
396 + EXP_ELEM_TO_BYTES (expout_size
)));
399 write_exp_elt_opcode (OP_STRING
);
400 write_exp_elt_longcst (len
);
401 write_exp_elt_longcst (type
);
403 for (i
= 0; i
< vec
->len
; ++i
)
405 write_exp_elt_longcst (vec
->tokens
[i
].length
);
406 memcpy (&expout
->elts
[expout_ptr
], vec
->tokens
[i
].ptr
,
407 vec
->tokens
[i
].length
);
408 expout_ptr
+= BYTES_TO_EXP_ELEM (vec
->tokens
[i
].length
);
411 write_exp_elt_longcst (len
);
412 write_exp_elt_opcode (OP_STRING
);
415 /* Add a bitstring constant to the end of the expression.
417 Bitstring constants are stored by first writing an expression element
418 that contains the length of the bitstring (in bits), then stuffing the
419 bitstring constant itself into however many expression elements are
420 needed to hold it, and then writing another expression element that
421 contains the length of the bitstring. I.E. an expression element at
422 each end of the bitstring records the bitstring length, so you can skip
423 over the expression elements containing the actual bitstring bytes from
424 either end of the bitstring. */
427 write_exp_bitstring (struct stoken str
)
429 int bits
= str
.length
; /* length in bits */
430 int len
= (bits
+ HOST_CHAR_BIT
- 1) / HOST_CHAR_BIT
;
434 /* Compute the number of expression elements required to hold the bitstring,
435 along with one expression element at each end to record the actual
436 bitstring length in bits. */
438 lenelt
= 2 + BYTES_TO_EXP_ELEM (len
);
440 /* Ensure that we have enough available expression elements to store
443 if ((expout_ptr
+ lenelt
) >= expout_size
)
445 expout_size
= max (expout_size
* 2, expout_ptr
+ lenelt
+ 10);
446 expout
= (struct expression
*)
447 xrealloc ((char *) expout
, (sizeof (struct expression
)
448 + EXP_ELEM_TO_BYTES (expout_size
)));
451 /* Write the leading length expression element (which advances the current
452 expression element index), then write the bitstring constant, and then
453 write the trailing length expression element. */
455 write_exp_elt_longcst ((LONGEST
) bits
);
456 strdata
= (char *) &expout
->elts
[expout_ptr
];
457 memcpy (strdata
, str
.ptr
, len
);
458 expout_ptr
+= lenelt
- 2;
459 write_exp_elt_longcst ((LONGEST
) bits
);
462 /* Add the appropriate elements for a minimal symbol to the end of
466 write_exp_msymbol (struct minimal_symbol
*msymbol
)
468 struct objfile
*objfile
= msymbol_objfile (msymbol
);
469 struct gdbarch
*gdbarch
= get_objfile_arch (objfile
);
471 CORE_ADDR addr
= SYMBOL_VALUE_ADDRESS (msymbol
);
472 struct obj_section
*section
= SYMBOL_OBJ_SECTION (msymbol
);
473 enum minimal_symbol_type type
= MSYMBOL_TYPE (msymbol
);
476 /* The minimal symbol might point to a function descriptor;
477 resolve it to the actual code address instead. */
478 pc
= gdbarch_convert_from_func_ptr_addr (gdbarch
, addr
, ¤t_target
);
481 /* In this case, assume we have a code symbol instead of
488 if (overlay_debugging
)
489 addr
= symbol_overlayed_address (addr
, section
);
491 write_exp_elt_opcode (OP_LONG
);
492 /* Let's make the type big enough to hold a 64-bit address. */
493 write_exp_elt_type (objfile_type (objfile
)->builtin_core_addr
);
494 write_exp_elt_longcst ((LONGEST
) addr
);
495 write_exp_elt_opcode (OP_LONG
);
497 if (section
&& section
->the_bfd_section
->flags
& SEC_THREAD_LOCAL
)
499 write_exp_elt_opcode (UNOP_MEMVAL_TLS
);
500 write_exp_elt_objfile (objfile
);
501 write_exp_elt_type (objfile_type (objfile
)->nodebug_tls_symbol
);
502 write_exp_elt_opcode (UNOP_MEMVAL_TLS
);
506 write_exp_elt_opcode (UNOP_MEMVAL
);
511 case mst_solib_trampoline
:
512 write_exp_elt_type (objfile_type (objfile
)->nodebug_text_symbol
);
519 write_exp_elt_type (objfile_type (objfile
)->nodebug_data_symbol
);
523 write_exp_elt_type (objfile_type (objfile
)->nodebug_unknown_symbol
);
526 write_exp_elt_opcode (UNOP_MEMVAL
);
529 /* Mark the current index as the starting location of a structure
530 expression. This is used when completing on field names. */
533 mark_struct_expression (void)
535 expout_last_struct
= expout_ptr
;
539 /* Recognize tokens that start with '$'. These include:
541 $regname A native register name or a "standard
544 $variable A convenience variable with a name chosen
547 $digits Value history with index <digits>, starting
548 from the first value which has index 1.
550 $$digits Value history with index <digits> relative
551 to the last value. I.E. $$0 is the last
552 value, $$1 is the one previous to that, $$2
553 is the one previous to $$1, etc.
555 $ | $0 | $$0 The last value in the value history.
557 $$ An abbreviation for the second to the last
558 value in the value history, I.E. $$1
563 write_dollar_variable (struct stoken str
)
565 struct symbol
*sym
= NULL
;
566 struct minimal_symbol
*msym
= NULL
;
567 struct internalvar
*isym
= NULL
;
569 /* Handle the tokens $digits; also $ (short for $0) and $$ (short for $$1)
570 and $$digits (equivalent to $<-digits> if you could type that). */
574 /* Double dollar means negate the number and add -1 as well.
575 Thus $$ alone means -1. */
576 if (str
.length
>= 2 && str
.ptr
[1] == '$')
583 /* Just dollars (one or two) */
587 /* Is the rest of the token digits? */
588 for (; i
< str
.length
; i
++)
589 if (!(str
.ptr
[i
] >= '0' && str
.ptr
[i
] <= '9'))
593 i
= atoi (str
.ptr
+ 1 + negate
);
599 /* Handle tokens that refer to machine registers:
600 $ followed by a register name. */
601 i
= user_reg_map_name_to_regnum (parse_gdbarch
,
602 str
.ptr
+ 1, str
.length
- 1);
604 goto handle_register
;
606 /* Any names starting with $ are probably debugger internal variables. */
608 isym
= lookup_only_internalvar (copy_name (str
) + 1);
611 write_exp_elt_opcode (OP_INTERNALVAR
);
612 write_exp_elt_intern (isym
);
613 write_exp_elt_opcode (OP_INTERNALVAR
);
617 /* On some systems, such as HP-UX and hppa-linux, certain system routines
618 have names beginning with $ or $$. Check for those, first. */
620 sym
= lookup_symbol (copy_name (str
), (struct block
*) NULL
,
621 VAR_DOMAIN
, (int *) NULL
);
624 write_exp_elt_opcode (OP_VAR_VALUE
);
625 write_exp_elt_block (block_found
); /* set by lookup_symbol */
626 write_exp_elt_sym (sym
);
627 write_exp_elt_opcode (OP_VAR_VALUE
);
630 msym
= lookup_minimal_symbol (copy_name (str
), NULL
, NULL
);
633 write_exp_msymbol (msym
);
637 /* Any other names are assumed to be debugger internal variables. */
639 write_exp_elt_opcode (OP_INTERNALVAR
);
640 write_exp_elt_intern (create_internalvar (copy_name (str
) + 1));
641 write_exp_elt_opcode (OP_INTERNALVAR
);
644 write_exp_elt_opcode (OP_LAST
);
645 write_exp_elt_longcst ((LONGEST
) i
);
646 write_exp_elt_opcode (OP_LAST
);
649 write_exp_elt_opcode (OP_REGISTER
);
652 write_exp_string (str
);
653 write_exp_elt_opcode (OP_REGISTER
);
659 find_template_name_end (char *p
)
662 int just_seen_right
= 0;
663 int just_seen_colon
= 0;
664 int just_seen_space
= 0;
666 if (!p
|| (*p
!= '<'))
677 /* In future, may want to allow these?? */
680 depth
++; /* start nested template */
681 if (just_seen_colon
|| just_seen_right
|| just_seen_space
)
682 return 0; /* but not after : or :: or > or space */
685 if (just_seen_colon
|| just_seen_right
)
686 return 0; /* end a (nested?) template */
687 just_seen_right
= 1; /* but not after : or :: */
688 if (--depth
== 0) /* also disallow >>, insist on > > */
689 return ++p
; /* if outermost ended, return */
692 if (just_seen_space
|| (just_seen_colon
> 1))
693 return 0; /* nested class spec coming up */
694 just_seen_colon
++; /* we allow :: but not :::: */
699 if (!((*p
>= 'a' && *p
<= 'z') || /* allow token chars */
700 (*p
>= 'A' && *p
<= 'Z') ||
701 (*p
>= '0' && *p
<= '9') ||
702 (*p
== '_') || (*p
== ',') || /* commas for template args */
703 (*p
== '&') || (*p
== '*') || /* pointer and ref types */
704 (*p
== '(') || (*p
== ')') || /* function types */
705 (*p
== '[') || (*p
== ']'))) /* array types */
720 /* Return a null-terminated temporary copy of the name
721 of a string token. */
724 copy_name (struct stoken token
)
726 /* Make sure there's enough space for the token. */
727 if (namecopy_size
< token
.length
+ 1)
729 namecopy_size
= token
.length
+ 1;
730 namecopy
= xrealloc (namecopy
, token
.length
+ 1);
733 memcpy (namecopy
, token
.ptr
, token
.length
);
734 namecopy
[token
.length
] = 0;
739 /* Reverse an expression from suffix form (in which it is constructed)
740 to prefix form (in which we can conveniently print or execute it).
741 Ordinarily this always returns -1. However, if EXPOUT_LAST_STRUCT
742 is not -1 (i.e., we are trying to complete a field name), it will
743 return the index of the subexpression which is the left-hand-side
744 of the struct operation at EXPOUT_LAST_STRUCT. */
747 prefixify_expression (struct expression
*expr
)
749 int len
= sizeof (struct expression
) + EXP_ELEM_TO_BYTES (expr
->nelts
);
750 struct expression
*temp
;
751 int inpos
= expr
->nelts
, outpos
= 0;
753 temp
= (struct expression
*) alloca (len
);
755 /* Copy the original expression into temp. */
756 memcpy (temp
, expr
, len
);
758 return prefixify_subexp (temp
, expr
, inpos
, outpos
);
761 /* Return the number of exp_elements in the postfix subexpression
762 of EXPR whose operator is at index ENDPOS - 1 in EXPR. */
765 length_of_subexp (struct expression
*expr
, int endpos
)
769 operator_length (expr
, endpos
, &oplen
, &args
);
773 oplen
+= length_of_subexp (expr
, endpos
- oplen
);
780 /* Sets *OPLENP to the length of the operator whose (last) index is
781 ENDPOS - 1 in EXPR, and sets *ARGSP to the number of arguments that
785 operator_length (struct expression
*expr
, int endpos
, int *oplenp
, int *argsp
)
787 expr
->language_defn
->la_exp_desc
->operator_length (expr
, endpos
,
791 /* Default value for operator_length in exp_descriptor vectors. */
794 operator_length_standard (struct expression
*expr
, int endpos
,
795 int *oplenp
, int *argsp
)
799 enum f90_range_type range_type
;
803 error (_("?error in operator_length_standard"));
805 i
= (int) expr
->elts
[endpos
- 1].opcode
;
811 oplen
= longest_to_int (expr
->elts
[endpos
- 2].longconst
);
812 oplen
= 5 + BYTES_TO_EXP_ELEM (oplen
+ 1);
835 case OP_F77_UNDETERMINED_ARGLIST
:
837 args
= 1 + longest_to_int (expr
->elts
[endpos
- 2].longconst
);
841 oplen
= 4 + longest_to_int (expr
->elts
[endpos
- 2].longconst
);
845 case OP_OBJC_MSGCALL
: /* Objective C message (method) call */
847 args
= 1 + longest_to_int (expr
->elts
[endpos
- 2].longconst
);
862 case UNOP_MEMVAL_TLS
:
880 case STRUCTOP_STRUCT
:
887 case OP_OBJC_NSSTRING
: /* Objective C Foundation Class NSString constant */
888 case OP_OBJC_SELECTOR
: /* Objective C "@selector" pseudo-op */
890 oplen
= longest_to_int (expr
->elts
[endpos
- 2].longconst
);
891 oplen
= 4 + BYTES_TO_EXP_ELEM (oplen
+ 1);
895 oplen
= longest_to_int (expr
->elts
[endpos
- 2].longconst
);
896 oplen
= (oplen
+ HOST_CHAR_BIT
- 1) / HOST_CHAR_BIT
;
897 oplen
= 4 + BYTES_TO_EXP_ELEM (oplen
);
902 args
= longest_to_int (expr
->elts
[endpos
- 2].longconst
);
903 args
-= longest_to_int (expr
->elts
[endpos
- 3].longconst
);
909 case TERNOP_SLICE_COUNT
:
914 case MULTI_SUBSCRIPT
:
916 args
= 1 + longest_to_int (expr
->elts
[endpos
- 2].longconst
);
919 case BINOP_ASSIGN_MODIFY
:
933 range_type
= longest_to_int (expr
->elts
[endpos
- 2].longconst
);
936 case LOW_BOUND_DEFAULT
:
937 case HIGH_BOUND_DEFAULT
:
940 case BOTH_BOUND_DEFAULT
:
943 case NONE_BOUND_DEFAULT
:
951 args
= 1 + (i
< (int) BINOP_END
);
958 /* Copy the subexpression ending just before index INEND in INEXPR
959 into OUTEXPR, starting at index OUTBEG.
960 In the process, convert it from suffix to prefix form.
961 If EXPOUT_LAST_STRUCT is -1, then this function always returns -1.
962 Otherwise, it returns the index of the subexpression which is the
963 left-hand-side of the expression at EXPOUT_LAST_STRUCT. */
966 prefixify_subexp (struct expression
*inexpr
,
967 struct expression
*outexpr
, int inend
, int outbeg
)
973 enum exp_opcode opcode
;
976 operator_length (inexpr
, inend
, &oplen
, &args
);
978 /* Copy the final operator itself, from the end of the input
979 to the beginning of the output. */
981 memcpy (&outexpr
->elts
[outbeg
], &inexpr
->elts
[inend
],
982 EXP_ELEM_TO_BYTES (oplen
));
985 if (expout_last_struct
== inend
)
986 result
= outbeg
- oplen
;
988 /* Find the lengths of the arg subexpressions. */
989 arglens
= (int *) alloca (args
* sizeof (int));
990 for (i
= args
- 1; i
>= 0; i
--)
992 oplen
= length_of_subexp (inexpr
, inend
);
997 /* Now copy each subexpression, preserving the order of
998 the subexpressions, but prefixifying each one.
999 In this loop, inend starts at the beginning of
1000 the expression this level is working on
1001 and marches forward over the arguments.
1002 outbeg does similarly in the output. */
1003 for (i
= 0; i
< args
; i
++)
1008 r
= prefixify_subexp (inexpr
, outexpr
, inend
, outbeg
);
1011 /* Return immediately. We probably have only parsed a
1012 partial expression, so we don't want to try to reverse
1013 the other operands. */
1022 /* This page contains the two entry points to this file. */
1024 /* Read an expression from the string *STRINGPTR points to,
1025 parse it, and return a pointer to a struct expression that we malloc.
1026 Use block BLOCK as the lexical context for variable names;
1027 if BLOCK is zero, use the block of the selected stack frame.
1028 Meanwhile, advance *STRINGPTR to point after the expression,
1029 at the first nonwhite character that is not part of the expression
1030 (possibly a null character).
1032 If COMMA is nonzero, stop if a comma is reached. */
1035 parse_exp_1 (char **stringptr
, struct block
*block
, int comma
)
1037 return parse_exp_in_context (stringptr
, block
, comma
, 0, NULL
);
1040 /* As for parse_exp_1, except that if VOID_CONTEXT_P, then
1041 no value is expected from the expression.
1042 OUT_SUBEXP is set when attempting to complete a field name; in this
1043 case it is set to the index of the subexpression on the
1044 left-hand-side of the struct op. If not doing such completion, it
1045 is left untouched. */
1047 static struct expression
*
1048 parse_exp_in_context (char **stringptr
, struct block
*block
, int comma
,
1049 int void_context_p
, int *out_subexp
)
1051 volatile struct gdb_exception except
;
1052 struct cleanup
*old_chain
;
1055 lexptr
= *stringptr
;
1059 type_stack_depth
= 0;
1060 expout_last_struct
= -1;
1062 comma_terminates
= comma
;
1064 if (lexptr
== 0 || *lexptr
== 0)
1065 error_no_arg (_("expression to compute"));
1067 old_chain
= make_cleanup (free_funcalls
, 0 /*ignore*/);
1070 expression_context_block
= block
;
1072 /* If no context specified, try using the current frame, if any. */
1073 if (!expression_context_block
)
1074 expression_context_block
= get_selected_block (&expression_context_pc
);
1076 expression_context_pc
= BLOCK_START (expression_context_block
);
1078 /* Fall back to using the current source static context, if any. */
1080 if (!expression_context_block
)
1082 struct symtab_and_line cursal
= get_current_source_symtab_and_line ();
1084 expression_context_block
1085 = BLOCKVECTOR_BLOCK (BLOCKVECTOR (cursal
.symtab
), STATIC_BLOCK
);
1086 if (expression_context_block
)
1087 expression_context_pc
= BLOCK_START (expression_context_block
);
1092 expout
= (struct expression
*)
1093 xmalloc (sizeof (struct expression
) + EXP_ELEM_TO_BYTES (expout_size
));
1094 expout
->language_defn
= current_language
;
1095 expout
->gdbarch
= get_current_arch ();
1097 TRY_CATCH (except
, RETURN_MASK_ALL
)
1099 if (current_language
->la_parser ())
1100 current_language
->la_error (NULL
);
1102 if (except
.reason
< 0)
1104 if (! in_parse_field
)
1107 throw_exception (except
);
1111 discard_cleanups (old_chain
);
1113 /* Record the actual number of expression elements, and then
1114 reallocate the expression memory so that we free up any
1117 expout
->nelts
= expout_ptr
;
1118 expout
= (struct expression
*)
1119 xrealloc ((char *) expout
,
1120 sizeof (struct expression
) + EXP_ELEM_TO_BYTES (expout_ptr
));;
1122 /* Convert expression from postfix form as generated by yacc
1123 parser, to a prefix form. */
1125 if (expressiondebug
)
1126 dump_raw_expression (expout
, gdb_stdlog
,
1127 "before conversion to prefix form");
1129 subexp
= prefixify_expression (expout
);
1131 *out_subexp
= subexp
;
1133 current_language
->la_post_parser (&expout
, void_context_p
);
1135 if (expressiondebug
)
1136 dump_prefix_expression (expout
, gdb_stdlog
);
1138 *stringptr
= lexptr
;
1142 /* Parse STRING as an expression, and complain if this fails
1143 to use up all of the contents of STRING. */
1146 parse_expression (char *string
)
1148 struct expression
*exp
;
1149 exp
= parse_exp_1 (&string
, 0, 0);
1151 error (_("Junk after end of expression."));
1155 /* Parse STRING as an expression. If parsing ends in the middle of a
1156 field reference, return the type of the left-hand-side of the
1157 reference; furthermore, if the parsing ends in the field name,
1158 return the field name in *NAME. In all other cases, return NULL.
1159 Returned non-NULL *NAME must be freed by the caller. */
1162 parse_field_expression (char *string
, char **name
)
1164 struct expression
*exp
= NULL
;
1167 volatile struct gdb_exception except
;
1169 TRY_CATCH (except
, RETURN_MASK_ALL
)
1172 exp
= parse_exp_in_context (&string
, 0, 0, 0, &subexp
);
1175 if (except
.reason
< 0 || ! exp
)
1177 if (expout_last_struct
== -1)
1183 *name
= extract_field_op (exp
, &subexp
);
1189 /* (*NAME) is a part of the EXP memory block freed below. */
1190 *name
= xstrdup (*name
);
1192 val
= evaluate_subexpression_type (exp
, subexp
);
1195 return value_type (val
);
1198 /* A post-parser that does nothing */
1201 null_post_parser (struct expression
**exp
, int void_context_p
)
1205 /* Stuff for maintaining a stack of types. Currently just used by C, but
1206 probably useful for any language which declares its types "backwards". */
1209 check_type_stack_depth (void)
1211 if (type_stack_depth
== type_stack_size
)
1213 type_stack_size
*= 2;
1214 type_stack
= (union type_stack_elt
*)
1215 xrealloc ((char *) type_stack
, type_stack_size
* sizeof (*type_stack
));
1220 push_type (enum type_pieces tp
)
1222 check_type_stack_depth ();
1223 type_stack
[type_stack_depth
++].piece
= tp
;
1227 push_type_int (int n
)
1229 check_type_stack_depth ();
1230 type_stack
[type_stack_depth
++].int_val
= n
;
1234 push_type_address_space (char *string
)
1236 push_type_int (address_space_name_to_int (parse_gdbarch
, string
));
1242 if (type_stack_depth
)
1243 return type_stack
[--type_stack_depth
].piece
;
1250 if (type_stack_depth
)
1251 return type_stack
[--type_stack_depth
].int_val
;
1252 /* "Can't happen". */
1256 /* Pop the type stack and return the type which corresponds to FOLLOW_TYPE
1257 as modified by all the stuff on the stack. */
1259 follow_types (struct type
*follow_type
)
1263 int make_volatile
= 0;
1264 int make_addr_space
= 0;
1268 switch (pop_type ())
1273 follow_type
= make_cv_type (make_const
,
1274 TYPE_VOLATILE (follow_type
),
1277 follow_type
= make_cv_type (TYPE_CONST (follow_type
),
1280 if (make_addr_space
)
1281 follow_type
= make_type_with_address_space (follow_type
,
1283 make_const
= make_volatile
= 0;
1284 make_addr_space
= 0;
1292 case tp_space_identifier
:
1293 make_addr_space
= pop_type_int ();
1296 follow_type
= lookup_pointer_type (follow_type
);
1298 follow_type
= make_cv_type (make_const
,
1299 TYPE_VOLATILE (follow_type
),
1302 follow_type
= make_cv_type (TYPE_CONST (follow_type
),
1305 if (make_addr_space
)
1306 follow_type
= make_type_with_address_space (follow_type
,
1308 make_const
= make_volatile
= 0;
1309 make_addr_space
= 0;
1312 follow_type
= lookup_reference_type (follow_type
);
1314 follow_type
= make_cv_type (make_const
,
1315 TYPE_VOLATILE (follow_type
),
1318 follow_type
= make_cv_type (TYPE_CONST (follow_type
),
1321 if (make_addr_space
)
1322 follow_type
= make_type_with_address_space (follow_type
,
1324 make_const
= make_volatile
= 0;
1325 make_addr_space
= 0;
1328 array_size
= pop_type_int ();
1329 /* FIXME-type-allocation: need a way to free this type when we are
1332 lookup_array_range_type (follow_type
,
1333 0, array_size
>= 0 ? array_size
- 1 : 0);
1335 TYPE_ARRAY_UPPER_BOUND_IS_UNDEFINED (follow_type
) = 1;
1338 /* FIXME-type-allocation: need a way to free this type when we are
1340 follow_type
= lookup_function_type (follow_type
);
1346 /* This function avoids direct calls to fprintf
1347 in the parser generated debug code. */
1349 parser_fprintf (FILE *x
, const char *y
, ...)
1354 vfprintf_unfiltered (gdb_stderr
, y
, args
);
1357 fprintf_unfiltered (gdb_stderr
, " Unknown FILE used.\n");
1358 vfprintf_unfiltered (gdb_stderr
, y
, args
);
1364 _initialize_parse (void)
1366 type_stack_size
= 80;
1367 type_stack_depth
= 0;
1368 type_stack
= (union type_stack_elt
*)
1369 xmalloc (type_stack_size
* sizeof (*type_stack
));
1371 add_setshow_zinteger_cmd ("expression", class_maintenance
,
1372 &expressiondebug
, _("\
1373 Set expression debugging."), _("\
1374 Show expression debugging."), _("\
1375 When non-zero, the internal representation of expressions will be printed."),
1377 show_expressiondebug
,
1378 &setdebuglist
, &showdebuglist
);