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
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 "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"
57 /* Standard set of definitions for printing, dumping, prefixifying,
58 * and evaluating expressions. */
60 const struct exp_descriptor exp_descriptor_standard
=
62 print_subexp_standard
,
63 operator_length_standard
,
65 dump_subexp_body_standard
,
66 evaluate_subexp_standard
69 /* Global variables declared in parser-defs.h (and commented there). */
70 struct expression
*expout
;
73 struct block
*expression_context_block
;
74 CORE_ADDR expression_context_pc
;
75 struct block
*innermost_block
;
77 union type_stack_elt
*type_stack
;
78 int type_stack_depth
, type_stack_size
;
84 /* True if parsing an expression to find a field reference. This is
85 only used by completion. */
88 /* The index of the last struct expression directly before a '.' or
89 '->'. This is set when parsing and is only used when completing a
90 field name. It is -1 if no dereference operation was found. */
91 static int expout_last_struct
= -1;
93 /* A temporary buffer for identifiers, so we can null-terminate them.
95 We allocate this with xrealloc. parse_exp_1 used to allocate with
96 alloca, using the size of the whole expression as a conservative
97 estimate of the space needed. However, macro expansion can
98 introduce names longer than the original expression; there's no
99 practical way to know beforehand how large that might be. */
101 size_t namecopy_size
;
103 static int expressiondebug
= 0;
105 show_expressiondebug (struct ui_file
*file
, int from_tty
,
106 struct cmd_list_element
*c
, const char *value
)
108 fprintf_filtered (file
, _("Expression debugging is %s.\n"), value
);
111 static void free_funcalls (void *ignore
);
113 static int prefixify_expression (struct expression
*);
115 static int prefixify_subexp (struct expression
*, struct expression
*, int,
118 static struct expression
*parse_exp_in_context (char **, struct block
*, int,
121 void _initialize_parse (void);
123 /* Data structure for saving values of arglist_len for function calls whose
124 arguments contain other function calls. */
128 struct funcall
*next
;
132 static struct funcall
*funcall_chain
;
134 /* Begin counting arguments for a function call,
135 saving the data about any containing call. */
142 new = (struct funcall
*) xmalloc (sizeof (struct funcall
));
143 new->next
= funcall_chain
;
144 new->arglist_len
= arglist_len
;
149 /* Return the number of arguments in a function call just terminated,
150 and restore the data for the containing function call. */
155 int val
= arglist_len
;
156 struct funcall
*call
= funcall_chain
;
157 funcall_chain
= call
->next
;
158 arglist_len
= call
->arglist_len
;
163 /* Free everything in the funcall chain.
164 Used when there is an error inside parsing. */
167 free_funcalls (void *ignore
)
169 struct funcall
*call
, *next
;
171 for (call
= funcall_chain
; call
; call
= next
)
178 /* This page contains the functions for adding data to the struct expression
179 being constructed. */
181 /* Add one element to the end of the expression. */
183 /* To avoid a bug in the Sun 4 compiler, we pass things that can fit into
184 a register through here */
187 write_exp_elt (union exp_element expelt
)
189 if (expout_ptr
>= expout_size
)
192 expout
= (struct expression
*)
193 xrealloc ((char *) expout
, sizeof (struct expression
)
194 + EXP_ELEM_TO_BYTES (expout_size
));
196 expout
->elts
[expout_ptr
++] = expelt
;
200 write_exp_elt_opcode (enum exp_opcode expelt
)
202 union exp_element tmp
;
203 memset (&tmp
, 0, sizeof (union exp_element
));
211 write_exp_elt_sym (struct symbol
*expelt
)
213 union exp_element tmp
;
214 memset (&tmp
, 0, sizeof (union exp_element
));
222 write_exp_elt_block (struct block
*b
)
224 union exp_element tmp
;
225 memset (&tmp
, 0, sizeof (union exp_element
));
231 write_exp_elt_objfile (struct objfile
*objfile
)
233 union exp_element tmp
;
234 memset (&tmp
, 0, sizeof (union exp_element
));
235 tmp
.objfile
= objfile
;
240 write_exp_elt_longcst (LONGEST expelt
)
242 union exp_element tmp
;
243 memset (&tmp
, 0, sizeof (union exp_element
));
245 tmp
.longconst
= expelt
;
251 write_exp_elt_dblcst (DOUBLEST expelt
)
253 union exp_element tmp
;
254 memset (&tmp
, 0, sizeof (union exp_element
));
256 tmp
.doubleconst
= expelt
;
262 write_exp_elt_decfloatcst (gdb_byte expelt
[16])
264 union exp_element tmp
;
267 for (index
= 0; index
< 16; index
++)
268 tmp
.decfloatconst
[index
] = expelt
[index
];
274 write_exp_elt_type (struct type
*expelt
)
276 union exp_element tmp
;
277 memset (&tmp
, 0, sizeof (union exp_element
));
285 write_exp_elt_intern (struct internalvar
*expelt
)
287 union exp_element tmp
;
288 memset (&tmp
, 0, sizeof (union exp_element
));
290 tmp
.internalvar
= expelt
;
295 /* Add a string constant to the end of the expression.
297 String constants are stored by first writing an expression element
298 that contains the length of the string, then stuffing the string
299 constant itself into however many expression elements are needed
300 to hold it, and then writing another expression element that contains
301 the length of the string. I.E. an expression element at each end of
302 the string records the string length, so you can skip over the
303 expression elements containing the actual string bytes from either
304 end of the string. Note that this also allows gdb to handle
305 strings with embedded null bytes, as is required for some languages.
307 Don't be fooled by the fact that the string is null byte terminated,
308 this is strictly for the convenience of debugging gdb itself. Gdb
309 Gdb does not depend up the string being null terminated, since the
310 actual length is recorded in expression elements at each end of the
311 string. The null byte is taken into consideration when computing how
312 many expression elements are required to hold the string constant, of
317 write_exp_string (struct stoken str
)
319 int len
= str
.length
;
323 /* Compute the number of expression elements required to hold the string
324 (including a null byte terminator), along with one expression element
325 at each end to record the actual string length (not including the
326 null byte terminator). */
328 lenelt
= 2 + BYTES_TO_EXP_ELEM (len
+ 1);
330 /* Ensure that we have enough available expression elements to store
333 if ((expout_ptr
+ lenelt
) >= expout_size
)
335 expout_size
= max (expout_size
* 2, expout_ptr
+ lenelt
+ 10);
336 expout
= (struct expression
*)
337 xrealloc ((char *) expout
, (sizeof (struct expression
)
338 + EXP_ELEM_TO_BYTES (expout_size
)));
341 /* Write the leading length expression element (which advances the current
342 expression element index), then write the string constant followed by a
343 terminating null byte, and then write the trailing length expression
346 write_exp_elt_longcst ((LONGEST
) len
);
347 strdata
= (char *) &expout
->elts
[expout_ptr
];
348 memcpy (strdata
, str
.ptr
, len
);
349 *(strdata
+ len
) = '\0';
350 expout_ptr
+= lenelt
- 2;
351 write_exp_elt_longcst ((LONGEST
) len
);
354 /* Add a bitstring constant to the end of the expression.
356 Bitstring constants are stored by first writing an expression element
357 that contains the length of the bitstring (in bits), then stuffing the
358 bitstring constant itself into however many expression elements are
359 needed to hold it, and then writing another expression element that
360 contains the length of the bitstring. I.E. an expression element at
361 each end of the bitstring records the bitstring length, so you can skip
362 over the expression elements containing the actual bitstring bytes from
363 either end of the bitstring. */
366 write_exp_bitstring (struct stoken str
)
368 int bits
= str
.length
; /* length in bits */
369 int len
= (bits
+ HOST_CHAR_BIT
- 1) / HOST_CHAR_BIT
;
373 /* Compute the number of expression elements required to hold the bitstring,
374 along with one expression element at each end to record the actual
375 bitstring length in bits. */
377 lenelt
= 2 + BYTES_TO_EXP_ELEM (len
);
379 /* Ensure that we have enough available expression elements to store
382 if ((expout_ptr
+ lenelt
) >= expout_size
)
384 expout_size
= max (expout_size
* 2, expout_ptr
+ lenelt
+ 10);
385 expout
= (struct expression
*)
386 xrealloc ((char *) expout
, (sizeof (struct expression
)
387 + EXP_ELEM_TO_BYTES (expout_size
)));
390 /* Write the leading length expression element (which advances the current
391 expression element index), then write the bitstring constant, and then
392 write the trailing length expression element. */
394 write_exp_elt_longcst ((LONGEST
) bits
);
395 strdata
= (char *) &expout
->elts
[expout_ptr
];
396 memcpy (strdata
, str
.ptr
, len
);
397 expout_ptr
+= lenelt
- 2;
398 write_exp_elt_longcst ((LONGEST
) bits
);
401 /* Add the appropriate elements for a minimal symbol to the end of
402 the expression. The rationale behind passing in text_symbol_type and
403 data_symbol_type was so that Modula-2 could pass in WORD for
404 data_symbol_type. Perhaps it still is useful to have those types vary
405 based on the language, but they no longer have names like "int", so
406 the initial rationale is gone. */
409 write_exp_msymbol (struct minimal_symbol
*msymbol
,
410 struct type
*text_symbol_type
,
411 struct type
*data_symbol_type
)
413 struct objfile
*objfile
= msymbol_objfile (msymbol
);
414 struct gdbarch
*gdbarch
= get_objfile_arch (objfile
);
416 CORE_ADDR addr
= SYMBOL_VALUE_ADDRESS (msymbol
);
417 asection
*bfd_section
= SYMBOL_BFD_SECTION (msymbol
);
418 enum minimal_symbol_type type
= msymbol
->type
;
421 /* The minimal symbol might point to a function descriptor;
422 resolve it to the actual code address instead. */
423 pc
= gdbarch_convert_from_func_ptr_addr (gdbarch
, addr
, ¤t_target
);
426 /* In this case, assume we have a code symbol instead of
433 if (overlay_debugging
)
434 addr
= symbol_overlayed_address (addr
, bfd_section
);
436 write_exp_elt_opcode (OP_LONG
);
437 /* Let's make the type big enough to hold a 64-bit address. */
438 write_exp_elt_type (builtin_type_CORE_ADDR
);
439 write_exp_elt_longcst ((LONGEST
) addr
);
440 write_exp_elt_opcode (OP_LONG
);
442 if (bfd_section
&& bfd_section
->flags
& SEC_THREAD_LOCAL
)
444 write_exp_elt_opcode (UNOP_MEMVAL_TLS
);
445 write_exp_elt_objfile (objfile
);
446 write_exp_elt_type (builtin_type (gdbarch
)->nodebug_tls_symbol
);
447 write_exp_elt_opcode (UNOP_MEMVAL_TLS
);
451 write_exp_elt_opcode (UNOP_MEMVAL
);
456 case mst_solib_trampoline
:
457 write_exp_elt_type (builtin_type (gdbarch
)->nodebug_text_symbol
);
464 write_exp_elt_type (builtin_type (gdbarch
)->nodebug_data_symbol
);
468 write_exp_elt_type (builtin_type (gdbarch
)->nodebug_unknown_symbol
);
471 write_exp_elt_opcode (UNOP_MEMVAL
);
474 /* Mark the current index as the starting location of a structure
475 expression. This is used when completing on field names. */
478 mark_struct_expression (void)
480 expout_last_struct
= expout_ptr
;
484 /* Recognize tokens that start with '$'. These include:
486 $regname A native register name or a "standard
489 $variable A convenience variable with a name chosen
492 $digits Value history with index <digits>, starting
493 from the first value which has index 1.
495 $$digits Value history with index <digits> relative
496 to the last value. I.E. $$0 is the last
497 value, $$1 is the one previous to that, $$2
498 is the one previous to $$1, etc.
500 $ | $0 | $$0 The last value in the value history.
502 $$ An abbreviation for the second to the last
503 value in the value history, I.E. $$1
508 write_dollar_variable (struct stoken str
)
510 struct symbol
*sym
= NULL
;
511 struct minimal_symbol
*msym
= NULL
;
512 struct internalvar
*isym
= NULL
;
514 /* Handle the tokens $digits; also $ (short for $0) and $$ (short for $$1)
515 and $$digits (equivalent to $<-digits> if you could type that). */
519 /* Double dollar means negate the number and add -1 as well.
520 Thus $$ alone means -1. */
521 if (str
.length
>= 2 && str
.ptr
[1] == '$')
528 /* Just dollars (one or two) */
532 /* Is the rest of the token digits? */
533 for (; i
< str
.length
; i
++)
534 if (!(str
.ptr
[i
] >= '0' && str
.ptr
[i
] <= '9'))
538 i
= atoi (str
.ptr
+ 1 + negate
);
544 /* Handle tokens that refer to machine registers:
545 $ followed by a register name. */
546 i
= frame_map_name_to_regnum (deprecated_safe_get_selected_frame (),
547 str
.ptr
+ 1, str
.length
- 1);
549 goto handle_register
;
551 /* Any names starting with $ are probably debugger internal variables. */
553 isym
= lookup_only_internalvar (copy_name (str
) + 1);
556 write_exp_elt_opcode (OP_INTERNALVAR
);
557 write_exp_elt_intern (isym
);
558 write_exp_elt_opcode (OP_INTERNALVAR
);
562 /* On some systems, such as HP-UX and hppa-linux, certain system routines
563 have names beginning with $ or $$. Check for those, first. */
565 sym
= lookup_symbol (copy_name (str
), (struct block
*) NULL
,
566 VAR_DOMAIN
, (int *) NULL
);
569 write_exp_elt_opcode (OP_VAR_VALUE
);
570 write_exp_elt_block (block_found
); /* set by lookup_symbol */
571 write_exp_elt_sym (sym
);
572 write_exp_elt_opcode (OP_VAR_VALUE
);
575 msym
= lookup_minimal_symbol (copy_name (str
), NULL
, NULL
);
578 write_exp_msymbol (msym
,
579 lookup_function_type (builtin_type_int
),
584 /* Any other names are assumed to be debugger internal variables. */
586 write_exp_elt_opcode (OP_INTERNALVAR
);
587 write_exp_elt_intern (create_internalvar (copy_name (str
) + 1));
588 write_exp_elt_opcode (OP_INTERNALVAR
);
591 write_exp_elt_opcode (OP_LAST
);
592 write_exp_elt_longcst ((LONGEST
) i
);
593 write_exp_elt_opcode (OP_LAST
);
596 write_exp_elt_opcode (OP_REGISTER
);
599 write_exp_string (str
);
600 write_exp_elt_opcode (OP_REGISTER
);
606 find_template_name_end (char *p
)
609 int just_seen_right
= 0;
610 int just_seen_colon
= 0;
611 int just_seen_space
= 0;
613 if (!p
|| (*p
!= '<'))
624 /* In future, may want to allow these?? */
627 depth
++; /* start nested template */
628 if (just_seen_colon
|| just_seen_right
|| just_seen_space
)
629 return 0; /* but not after : or :: or > or space */
632 if (just_seen_colon
|| just_seen_right
)
633 return 0; /* end a (nested?) template */
634 just_seen_right
= 1; /* but not after : or :: */
635 if (--depth
== 0) /* also disallow >>, insist on > > */
636 return ++p
; /* if outermost ended, return */
639 if (just_seen_space
|| (just_seen_colon
> 1))
640 return 0; /* nested class spec coming up */
641 just_seen_colon
++; /* we allow :: but not :::: */
646 if (!((*p
>= 'a' && *p
<= 'z') || /* allow token chars */
647 (*p
>= 'A' && *p
<= 'Z') ||
648 (*p
>= '0' && *p
<= '9') ||
649 (*p
== '_') || (*p
== ',') || /* commas for template args */
650 (*p
== '&') || (*p
== '*') || /* pointer and ref types */
651 (*p
== '(') || (*p
== ')') || /* function types */
652 (*p
== '[') || (*p
== ']'))) /* array types */
667 /* Return a null-terminated temporary copy of the name
668 of a string token. */
671 copy_name (struct stoken token
)
673 /* Make sure there's enough space for the token. */
674 if (namecopy_size
< token
.length
+ 1)
676 namecopy_size
= token
.length
+ 1;
677 namecopy
= xrealloc (namecopy
, token
.length
+ 1);
680 memcpy (namecopy
, token
.ptr
, token
.length
);
681 namecopy
[token
.length
] = 0;
686 /* Reverse an expression from suffix form (in which it is constructed)
687 to prefix form (in which we can conveniently print or execute it).
688 Ordinarily this always returns -1. However, if EXPOUT_LAST_STRUCT
689 is not -1 (i.e., we are trying to complete a field name), it will
690 return the index of the subexpression which is the left-hand-side
691 of the struct operation at EXPOUT_LAST_STRUCT. */
694 prefixify_expression (struct expression
*expr
)
696 int len
= sizeof (struct expression
) + EXP_ELEM_TO_BYTES (expr
->nelts
);
697 struct expression
*temp
;
698 int inpos
= expr
->nelts
, outpos
= 0;
700 temp
= (struct expression
*) alloca (len
);
702 /* Copy the original expression into temp. */
703 memcpy (temp
, expr
, len
);
705 return prefixify_subexp (temp
, expr
, inpos
, outpos
);
708 /* Return the number of exp_elements in the postfix subexpression
709 of EXPR whose operator is at index ENDPOS - 1 in EXPR. */
712 length_of_subexp (struct expression
*expr
, int endpos
)
716 operator_length (expr
, endpos
, &oplen
, &args
);
720 oplen
+= length_of_subexp (expr
, endpos
- oplen
);
727 /* Sets *OPLENP to the length of the operator whose (last) index is
728 ENDPOS - 1 in EXPR, and sets *ARGSP to the number of arguments that
732 operator_length (struct expression
*expr
, int endpos
, int *oplenp
, int *argsp
)
734 expr
->language_defn
->la_exp_desc
->operator_length (expr
, endpos
,
738 /* Default value for operator_length in exp_descriptor vectors. */
741 operator_length_standard (struct expression
*expr
, int endpos
,
742 int *oplenp
, int *argsp
)
746 enum f90_range_type range_type
;
750 error (_("?error in operator_length_standard"));
752 i
= (int) expr
->elts
[endpos
- 1].opcode
;
758 oplen
= longest_to_int (expr
->elts
[endpos
- 2].longconst
);
759 oplen
= 5 + BYTES_TO_EXP_ELEM (oplen
+ 1);
782 case OP_F77_UNDETERMINED_ARGLIST
:
784 args
= 1 + longest_to_int (expr
->elts
[endpos
- 2].longconst
);
787 case OP_OBJC_MSGCALL
: /* Objective C message (method) call */
789 args
= 1 + longest_to_int (expr
->elts
[endpos
- 2].longconst
);
804 case UNOP_MEMVAL_TLS
:
822 case STRUCTOP_STRUCT
:
829 case OP_OBJC_NSSTRING
: /* Objective C Foundation Class NSString constant */
830 case OP_OBJC_SELECTOR
: /* Objective C "@selector" pseudo-op */
832 oplen
= longest_to_int (expr
->elts
[endpos
- 2].longconst
);
833 oplen
= 4 + BYTES_TO_EXP_ELEM (oplen
+ 1);
837 oplen
= longest_to_int (expr
->elts
[endpos
- 2].longconst
);
838 oplen
= (oplen
+ HOST_CHAR_BIT
- 1) / HOST_CHAR_BIT
;
839 oplen
= 4 + BYTES_TO_EXP_ELEM (oplen
);
844 args
= longest_to_int (expr
->elts
[endpos
- 2].longconst
);
845 args
-= longest_to_int (expr
->elts
[endpos
- 3].longconst
);
851 case TERNOP_SLICE_COUNT
:
856 case MULTI_SUBSCRIPT
:
858 args
= 1 + longest_to_int (expr
->elts
[endpos
- 2].longconst
);
861 case BINOP_ASSIGN_MODIFY
:
875 range_type
= longest_to_int (expr
->elts
[endpos
- 2].longconst
);
878 case LOW_BOUND_DEFAULT
:
879 case HIGH_BOUND_DEFAULT
:
882 case BOTH_BOUND_DEFAULT
:
885 case NONE_BOUND_DEFAULT
:
893 args
= 1 + (i
< (int) BINOP_END
);
900 /* Copy the subexpression ending just before index INEND in INEXPR
901 into OUTEXPR, starting at index OUTBEG.
902 In the process, convert it from suffix to prefix form.
903 If EXPOUT_LAST_STRUCT is -1, then this function always returns -1.
904 Otherwise, it returns the index of the subexpression which is the
905 left-hand-side of the expression at EXPOUT_LAST_STRUCT. */
908 prefixify_subexp (struct expression
*inexpr
,
909 struct expression
*outexpr
, int inend
, int outbeg
)
915 enum exp_opcode opcode
;
918 operator_length (inexpr
, inend
, &oplen
, &args
);
920 /* Copy the final operator itself, from the end of the input
921 to the beginning of the output. */
923 memcpy (&outexpr
->elts
[outbeg
], &inexpr
->elts
[inend
],
924 EXP_ELEM_TO_BYTES (oplen
));
927 if (expout_last_struct
== inend
)
928 result
= outbeg
- oplen
;
930 /* Find the lengths of the arg subexpressions. */
931 arglens
= (int *) alloca (args
* sizeof (int));
932 for (i
= args
- 1; i
>= 0; i
--)
934 oplen
= length_of_subexp (inexpr
, inend
);
939 /* Now copy each subexpression, preserving the order of
940 the subexpressions, but prefixifying each one.
941 In this loop, inend starts at the beginning of
942 the expression this level is working on
943 and marches forward over the arguments.
944 outbeg does similarly in the output. */
945 for (i
= 0; i
< args
; i
++)
950 r
= prefixify_subexp (inexpr
, outexpr
, inend
, outbeg
);
953 /* Return immediately. We probably have only parsed a
954 partial expression, so we don't want to try to reverse
955 the other operands. */
964 /* This page contains the two entry points to this file. */
966 /* Read an expression from the string *STRINGPTR points to,
967 parse it, and return a pointer to a struct expression that we malloc.
968 Use block BLOCK as the lexical context for variable names;
969 if BLOCK is zero, use the block of the selected stack frame.
970 Meanwhile, advance *STRINGPTR to point after the expression,
971 at the first nonwhite character that is not part of the expression
972 (possibly a null character).
974 If COMMA is nonzero, stop if a comma is reached. */
977 parse_exp_1 (char **stringptr
, struct block
*block
, int comma
)
979 return parse_exp_in_context (stringptr
, block
, comma
, 0, NULL
);
982 /* As for parse_exp_1, except that if VOID_CONTEXT_P, then
983 no value is expected from the expression.
984 OUT_SUBEXP is set when attempting to complete a field name; in this
985 case it is set to the index of the subexpression on the
986 left-hand-side of the struct op. If not doing such completion, it
987 is left untouched. */
989 static struct expression
*
990 parse_exp_in_context (char **stringptr
, struct block
*block
, int comma
,
991 int void_context_p
, int *out_subexp
)
993 volatile struct gdb_exception except
;
994 struct cleanup
*old_chain
;
1001 type_stack_depth
= 0;
1002 expout_last_struct
= -1;
1004 comma_terminates
= comma
;
1006 if (lexptr
== 0 || *lexptr
== 0)
1007 error_no_arg (_("expression to compute"));
1009 old_chain
= make_cleanup (free_funcalls
, 0 /*ignore*/);
1012 expression_context_block
= block
;
1014 /* If no context specified, try using the current frame, if any. */
1015 if (!expression_context_block
)
1016 expression_context_block
= get_selected_block (&expression_context_pc
);
1018 expression_context_pc
= BLOCK_START (expression_context_block
);
1020 /* Fall back to using the current source static context, if any. */
1022 if (!expression_context_block
)
1024 struct symtab_and_line cursal
= get_current_source_symtab_and_line ();
1026 expression_context_block
1027 = BLOCKVECTOR_BLOCK (BLOCKVECTOR (cursal
.symtab
), STATIC_BLOCK
);
1028 if (expression_context_block
)
1029 expression_context_pc
= BLOCK_START (expression_context_block
);
1034 expout
= (struct expression
*)
1035 xmalloc (sizeof (struct expression
) + EXP_ELEM_TO_BYTES (expout_size
));
1036 expout
->language_defn
= current_language
;
1038 TRY_CATCH (except
, RETURN_MASK_ALL
)
1040 if (current_language
->la_parser ())
1041 current_language
->la_error (NULL
);
1043 if (except
.reason
< 0)
1045 if (! in_parse_field
)
1048 throw_exception (except
);
1052 discard_cleanups (old_chain
);
1054 /* Record the actual number of expression elements, and then
1055 reallocate the expression memory so that we free up any
1058 expout
->nelts
= expout_ptr
;
1059 expout
= (struct expression
*)
1060 xrealloc ((char *) expout
,
1061 sizeof (struct expression
) + EXP_ELEM_TO_BYTES (expout_ptr
));;
1063 /* Convert expression from postfix form as generated by yacc
1064 parser, to a prefix form. */
1066 if (expressiondebug
)
1067 dump_raw_expression (expout
, gdb_stdlog
,
1068 "before conversion to prefix form");
1070 subexp
= prefixify_expression (expout
);
1072 *out_subexp
= subexp
;
1074 current_language
->la_post_parser (&expout
, void_context_p
);
1076 if (expressiondebug
)
1077 dump_prefix_expression (expout
, gdb_stdlog
);
1079 *stringptr
= lexptr
;
1083 /* Parse STRING as an expression, and complain if this fails
1084 to use up all of the contents of STRING. */
1087 parse_expression (char *string
)
1089 struct expression
*exp
;
1090 exp
= parse_exp_1 (&string
, 0, 0);
1092 error (_("Junk after end of expression."));
1096 /* Parse STRING as an expression. If parsing ends in the middle of a
1097 field reference, return the type of the left-hand-side of the
1098 reference; furthermore, if the parsing ends in the field name,
1099 return the field name in *NAME. In all other cases, return NULL. */
1102 parse_field_expression (char *string
, char **name
)
1104 struct expression
*exp
= NULL
;
1107 volatile struct gdb_exception except
;
1109 TRY_CATCH (except
, RETURN_MASK_ALL
)
1112 exp
= parse_exp_in_context (&string
, 0, 0, 0, &subexp
);
1115 if (except
.reason
< 0 || ! exp
)
1117 if (expout_last_struct
== -1)
1123 *name
= extract_field_op (exp
, &subexp
);
1129 val
= evaluate_subexpression_type (exp
, subexp
);
1132 return value_type (val
);
1135 /* A post-parser that does nothing */
1138 null_post_parser (struct expression
**exp
, int void_context_p
)
1142 /* Stuff for maintaining a stack of types. Currently just used by C, but
1143 probably useful for any language which declares its types "backwards". */
1146 check_type_stack_depth (void)
1148 if (type_stack_depth
== type_stack_size
)
1150 type_stack_size
*= 2;
1151 type_stack
= (union type_stack_elt
*)
1152 xrealloc ((char *) type_stack
, type_stack_size
* sizeof (*type_stack
));
1157 push_type (enum type_pieces tp
)
1159 check_type_stack_depth ();
1160 type_stack
[type_stack_depth
++].piece
= tp
;
1164 push_type_int (int n
)
1166 check_type_stack_depth ();
1167 type_stack
[type_stack_depth
++].int_val
= n
;
1171 push_type_address_space (char *string
)
1173 push_type_int (address_space_name_to_int (string
));
1179 if (type_stack_depth
)
1180 return type_stack
[--type_stack_depth
].piece
;
1187 if (type_stack_depth
)
1188 return type_stack
[--type_stack_depth
].int_val
;
1189 /* "Can't happen". */
1193 /* Pop the type stack and return the type which corresponds to FOLLOW_TYPE
1194 as modified by all the stuff on the stack. */
1196 follow_types (struct type
*follow_type
)
1200 int make_volatile
= 0;
1201 int make_addr_space
= 0;
1203 struct type
*range_type
;
1206 switch (pop_type ())
1211 follow_type
= make_cv_type (make_const
,
1212 TYPE_VOLATILE (follow_type
),
1215 follow_type
= make_cv_type (TYPE_CONST (follow_type
),
1218 if (make_addr_space
)
1219 follow_type
= make_type_with_address_space (follow_type
,
1221 make_const
= make_volatile
= 0;
1222 make_addr_space
= 0;
1230 case tp_space_identifier
:
1231 make_addr_space
= pop_type_int ();
1234 follow_type
= lookup_pointer_type (follow_type
);
1236 follow_type
= make_cv_type (make_const
,
1237 TYPE_VOLATILE (follow_type
),
1240 follow_type
= make_cv_type (TYPE_CONST (follow_type
),
1243 if (make_addr_space
)
1244 follow_type
= make_type_with_address_space (follow_type
,
1246 make_const
= make_volatile
= 0;
1247 make_addr_space
= 0;
1250 follow_type
= lookup_reference_type (follow_type
);
1252 follow_type
= make_cv_type (make_const
,
1253 TYPE_VOLATILE (follow_type
),
1256 follow_type
= make_cv_type (TYPE_CONST (follow_type
),
1259 if (make_addr_space
)
1260 follow_type
= make_type_with_address_space (follow_type
,
1262 make_const
= make_volatile
= 0;
1263 make_addr_space
= 0;
1266 array_size
= pop_type_int ();
1267 /* FIXME-type-allocation: need a way to free this type when we are
1270 create_range_type ((struct type
*) NULL
,
1271 builtin_type_int
, 0,
1272 array_size
>= 0 ? array_size
- 1 : 0);
1274 create_array_type ((struct type
*) NULL
,
1275 follow_type
, range_type
);
1277 TYPE_ARRAY_UPPER_BOUND_TYPE (follow_type
)
1278 = BOUND_CANNOT_BE_DETERMINED
;
1281 /* FIXME-type-allocation: need a way to free this type when we are
1283 follow_type
= lookup_function_type (follow_type
);
1289 /* This function avoids direct calls to fprintf
1290 in the parser generated debug code. */
1292 parser_fprintf (FILE *x
, const char *y
, ...)
1297 vfprintf_unfiltered (gdb_stderr
, y
, args
);
1300 fprintf_unfiltered (gdb_stderr
, " Unknown FILE used.\n");
1301 vfprintf_unfiltered (gdb_stderr
, y
, args
);
1307 _initialize_parse (void)
1309 type_stack_size
= 80;
1310 type_stack_depth
= 0;
1311 type_stack
= (union type_stack_elt
*)
1312 xmalloc (type_stack_size
* sizeof (*type_stack
));
1314 add_setshow_zinteger_cmd ("expression", class_maintenance
,
1315 &expressiondebug
, _("\
1316 Set expression debugging."), _("\
1317 Show expression debugging."), _("\
1318 When non-zero, the internal representation of expressions will be printed."),
1320 show_expressiondebug
,
1321 &setdebuglist
, &showdebuglist
);