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
,
66 dump_subexp_body_standard
,
67 evaluate_subexp_standard
70 /* Global variables declared in parser-defs.h (and commented there). */
71 struct expression
*expout
;
74 struct block
*expression_context_block
;
75 CORE_ADDR expression_context_pc
;
76 struct block
*innermost_block
;
78 union type_stack_elt
*type_stack
;
79 int type_stack_depth
, type_stack_size
;
85 /* True if parsing an expression to find a field reference. This is
86 only used by completion. */
89 /* The index of the last struct expression directly before a '.' or
90 '->'. This is set when parsing and is only used when completing a
91 field name. It is -1 if no dereference operation was found. */
92 static int expout_last_struct
= -1;
94 /* A temporary buffer for identifiers, so we can null-terminate them.
96 We allocate this with xrealloc. parse_exp_1 used to allocate with
97 alloca, using the size of the whole expression as a conservative
98 estimate of the space needed. However, macro expansion can
99 introduce names longer than the original expression; there's no
100 practical way to know beforehand how large that might be. */
102 size_t namecopy_size
;
104 static int expressiondebug
= 0;
106 show_expressiondebug (struct ui_file
*file
, int from_tty
,
107 struct cmd_list_element
*c
, const char *value
)
109 fprintf_filtered (file
, _("Expression debugging is %s.\n"), value
);
112 static void free_funcalls (void *ignore
);
114 static int prefixify_expression (struct expression
*);
116 static int prefixify_subexp (struct expression
*, struct expression
*, int,
119 static struct expression
*parse_exp_in_context (char **, struct block
*, int,
122 void _initialize_parse (void);
124 /* Data structure for saving values of arglist_len for function calls whose
125 arguments contain other function calls. */
129 struct funcall
*next
;
133 static struct funcall
*funcall_chain
;
135 /* Begin counting arguments for a function call,
136 saving the data about any containing call. */
143 new = (struct funcall
*) xmalloc (sizeof (struct funcall
));
144 new->next
= funcall_chain
;
145 new->arglist_len
= arglist_len
;
150 /* Return the number of arguments in a function call just terminated,
151 and restore the data for the containing function call. */
156 int val
= arglist_len
;
157 struct funcall
*call
= funcall_chain
;
158 funcall_chain
= call
->next
;
159 arglist_len
= call
->arglist_len
;
164 /* Free everything in the funcall chain.
165 Used when there is an error inside parsing. */
168 free_funcalls (void *ignore
)
170 struct funcall
*call
, *next
;
172 for (call
= funcall_chain
; call
; call
= next
)
179 /* This page contains the functions for adding data to the struct expression
180 being constructed. */
182 /* Add one element to the end of the expression. */
184 /* To avoid a bug in the Sun 4 compiler, we pass things that can fit into
185 a register through here */
188 write_exp_elt (union exp_element expelt
)
190 if (expout_ptr
>= expout_size
)
193 expout
= (struct expression
*)
194 xrealloc ((char *) expout
, sizeof (struct expression
)
195 + EXP_ELEM_TO_BYTES (expout_size
));
197 expout
->elts
[expout_ptr
++] = expelt
;
201 write_exp_elt_opcode (enum exp_opcode expelt
)
203 union exp_element tmp
;
204 memset (&tmp
, 0, sizeof (union exp_element
));
212 write_exp_elt_sym (struct symbol
*expelt
)
214 union exp_element tmp
;
215 memset (&tmp
, 0, sizeof (union exp_element
));
223 write_exp_elt_block (struct block
*b
)
225 union exp_element tmp
;
226 memset (&tmp
, 0, sizeof (union exp_element
));
232 write_exp_elt_objfile (struct objfile
*objfile
)
234 union exp_element tmp
;
235 memset (&tmp
, 0, sizeof (union exp_element
));
236 tmp
.objfile
= objfile
;
241 write_exp_elt_longcst (LONGEST expelt
)
243 union exp_element tmp
;
244 memset (&tmp
, 0, sizeof (union exp_element
));
246 tmp
.longconst
= expelt
;
252 write_exp_elt_dblcst (DOUBLEST expelt
)
254 union exp_element tmp
;
255 memset (&tmp
, 0, sizeof (union exp_element
));
257 tmp
.doubleconst
= expelt
;
263 write_exp_elt_decfloatcst (gdb_byte expelt
[16])
265 union exp_element tmp
;
268 for (index
= 0; index
< 16; index
++)
269 tmp
.decfloatconst
[index
] = expelt
[index
];
275 write_exp_elt_type (struct type
*expelt
)
277 union exp_element tmp
;
278 memset (&tmp
, 0, sizeof (union exp_element
));
286 write_exp_elt_intern (struct internalvar
*expelt
)
288 union exp_element tmp
;
289 memset (&tmp
, 0, sizeof (union exp_element
));
291 tmp
.internalvar
= expelt
;
296 /* Add a string constant to the end of the expression.
298 String constants are stored by first writing an expression element
299 that contains the length of the string, then stuffing the string
300 constant itself into however many expression elements are needed
301 to hold it, and then writing another expression element that contains
302 the length of the string. I.E. an expression element at each end of
303 the string records the string length, so you can skip over the
304 expression elements containing the actual string bytes from either
305 end of the string. Note that this also allows gdb to handle
306 strings with embedded null bytes, as is required for some languages.
308 Don't be fooled by the fact that the string is null byte terminated,
309 this is strictly for the convenience of debugging gdb itself.
310 Gdb does not depend up the string being null terminated, since the
311 actual length is recorded in expression elements at each end of the
312 string. The null byte is taken into consideration when computing how
313 many expression elements are required to hold the string constant, of
318 write_exp_string (struct stoken str
)
320 int len
= str
.length
;
324 /* Compute the number of expression elements required to hold the string
325 (including a null byte terminator), along with one expression element
326 at each end to record the actual string length (not including the
327 null byte terminator). */
329 lenelt
= 2 + BYTES_TO_EXP_ELEM (len
+ 1);
331 /* Ensure that we have enough available expression elements to store
334 if ((expout_ptr
+ lenelt
) >= expout_size
)
336 expout_size
= max (expout_size
* 2, expout_ptr
+ lenelt
+ 10);
337 expout
= (struct expression
*)
338 xrealloc ((char *) expout
, (sizeof (struct expression
)
339 + EXP_ELEM_TO_BYTES (expout_size
)));
342 /* Write the leading length expression element (which advances the current
343 expression element index), then write the string constant followed by a
344 terminating null byte, and then write the trailing length expression
347 write_exp_elt_longcst ((LONGEST
) len
);
348 strdata
= (char *) &expout
->elts
[expout_ptr
];
349 memcpy (strdata
, str
.ptr
, len
);
350 *(strdata
+ len
) = '\0';
351 expout_ptr
+= lenelt
- 2;
352 write_exp_elt_longcst ((LONGEST
) len
);
355 /* Add a vector of string constants to the end of the expression.
357 This adds an OP_STRING operation, but encodes the contents
358 differently from write_exp_string. The language is expected to
359 handle evaluation of this expression itself.
361 After the usual OP_STRING header, TYPE is written into the
362 expression as a long constant. The interpretation of this field is
363 up to the language evaluator.
365 Next, each string in VEC is written. The length is written as a
366 long constant, followed by the contents of the string. */
369 write_exp_string_vector (int type
, struct stoken_vector
*vec
)
373 /* Compute the size. We compute the size in number of slots to
374 avoid issues with string padding. */
376 for (i
= 0; i
< vec
->len
; ++i
)
378 /* One slot for the length of this element, plus the number of
379 slots needed for this string. */
380 n_slots
+= 1 + BYTES_TO_EXP_ELEM (vec
->tokens
[i
].length
);
383 /* One more slot for the type of the string. */
386 /* Now compute a phony string length. */
387 len
= EXP_ELEM_TO_BYTES (n_slots
) - 1;
390 if ((expout_ptr
+ n_slots
) >= expout_size
)
392 expout_size
= max (expout_size
* 2, expout_ptr
+ n_slots
+ 10);
393 expout
= (struct expression
*)
394 xrealloc ((char *) expout
, (sizeof (struct expression
)
395 + EXP_ELEM_TO_BYTES (expout_size
)));
398 write_exp_elt_opcode (OP_STRING
);
399 write_exp_elt_longcst (len
);
400 write_exp_elt_longcst (type
);
402 for (i
= 0; i
< vec
->len
; ++i
)
404 write_exp_elt_longcst (vec
->tokens
[i
].length
);
405 memcpy (&expout
->elts
[expout_ptr
], vec
->tokens
[i
].ptr
,
406 vec
->tokens
[i
].length
);
407 expout_ptr
+= BYTES_TO_EXP_ELEM (vec
->tokens
[i
].length
);
410 write_exp_elt_longcst (len
);
411 write_exp_elt_opcode (OP_STRING
);
414 /* Add a bitstring constant to the end of the expression.
416 Bitstring constants are stored by first writing an expression element
417 that contains the length of the bitstring (in bits), then stuffing the
418 bitstring constant itself into however many expression elements are
419 needed to hold it, and then writing another expression element that
420 contains the length of the bitstring. I.E. an expression element at
421 each end of the bitstring records the bitstring length, so you can skip
422 over the expression elements containing the actual bitstring bytes from
423 either end of the bitstring. */
426 write_exp_bitstring (struct stoken str
)
428 int bits
= str
.length
; /* length in bits */
429 int len
= (bits
+ HOST_CHAR_BIT
- 1) / HOST_CHAR_BIT
;
433 /* Compute the number of expression elements required to hold the bitstring,
434 along with one expression element at each end to record the actual
435 bitstring length in bits. */
437 lenelt
= 2 + BYTES_TO_EXP_ELEM (len
);
439 /* Ensure that we have enough available expression elements to store
442 if ((expout_ptr
+ lenelt
) >= expout_size
)
444 expout_size
= max (expout_size
* 2, expout_ptr
+ lenelt
+ 10);
445 expout
= (struct expression
*)
446 xrealloc ((char *) expout
, (sizeof (struct expression
)
447 + EXP_ELEM_TO_BYTES (expout_size
)));
450 /* Write the leading length expression element (which advances the current
451 expression element index), then write the bitstring constant, and then
452 write the trailing length expression element. */
454 write_exp_elt_longcst ((LONGEST
) bits
);
455 strdata
= (char *) &expout
->elts
[expout_ptr
];
456 memcpy (strdata
, str
.ptr
, len
);
457 expout_ptr
+= lenelt
- 2;
458 write_exp_elt_longcst ((LONGEST
) bits
);
461 /* Add the appropriate elements for a minimal symbol to the end of
465 write_exp_msymbol (struct minimal_symbol
*msymbol
)
467 struct objfile
*objfile
= msymbol_objfile (msymbol
);
468 struct gdbarch
*gdbarch
= get_objfile_arch (objfile
);
470 CORE_ADDR addr
= SYMBOL_VALUE_ADDRESS (msymbol
);
471 struct obj_section
*section
= SYMBOL_OBJ_SECTION (msymbol
);
472 enum minimal_symbol_type type
= MSYMBOL_TYPE (msymbol
);
475 /* The minimal symbol might point to a function descriptor;
476 resolve it to the actual code address instead. */
477 pc
= gdbarch_convert_from_func_ptr_addr (gdbarch
, addr
, ¤t_target
);
480 /* In this case, assume we have a code symbol instead of
487 if (overlay_debugging
)
488 addr
= symbol_overlayed_address (addr
, section
);
490 write_exp_elt_opcode (OP_LONG
);
491 /* Let's make the type big enough to hold a 64-bit address. */
492 write_exp_elt_type (objfile_type (objfile
)->builtin_core_addr
);
493 write_exp_elt_longcst ((LONGEST
) addr
);
494 write_exp_elt_opcode (OP_LONG
);
496 if (section
&& section
->the_bfd_section
->flags
& SEC_THREAD_LOCAL
)
498 write_exp_elt_opcode (UNOP_MEMVAL_TLS
);
499 write_exp_elt_objfile (objfile
);
500 write_exp_elt_type (objfile_type (objfile
)->nodebug_tls_symbol
);
501 write_exp_elt_opcode (UNOP_MEMVAL_TLS
);
505 write_exp_elt_opcode (UNOP_MEMVAL
);
510 case mst_solib_trampoline
:
511 write_exp_elt_type (objfile_type (objfile
)->nodebug_text_symbol
);
518 write_exp_elt_type (objfile_type (objfile
)->nodebug_data_symbol
);
522 write_exp_elt_type (objfile_type (objfile
)->nodebug_unknown_symbol
);
525 write_exp_elt_opcode (UNOP_MEMVAL
);
528 /* Mark the current index as the starting location of a structure
529 expression. This is used when completing on field names. */
532 mark_struct_expression (void)
534 expout_last_struct
= expout_ptr
;
538 /* Recognize tokens that start with '$'. These include:
540 $regname A native register name or a "standard
543 $variable A convenience variable with a name chosen
546 $digits Value history with index <digits>, starting
547 from the first value which has index 1.
549 $$digits Value history with index <digits> relative
550 to the last value. I.E. $$0 is the last
551 value, $$1 is the one previous to that, $$2
552 is the one previous to $$1, etc.
554 $ | $0 | $$0 The last value in the value history.
556 $$ An abbreviation for the second to the last
557 value in the value history, I.E. $$1
562 write_dollar_variable (struct stoken str
)
564 struct symbol
*sym
= NULL
;
565 struct minimal_symbol
*msym
= NULL
;
566 struct internalvar
*isym
= NULL
;
568 /* Handle the tokens $digits; also $ (short for $0) and $$ (short for $$1)
569 and $$digits (equivalent to $<-digits> if you could type that). */
573 /* Double dollar means negate the number and add -1 as well.
574 Thus $$ alone means -1. */
575 if (str
.length
>= 2 && str
.ptr
[1] == '$')
582 /* Just dollars (one or two) */
586 /* Is the rest of the token digits? */
587 for (; i
< str
.length
; i
++)
588 if (!(str
.ptr
[i
] >= '0' && str
.ptr
[i
] <= '9'))
592 i
= atoi (str
.ptr
+ 1 + negate
);
598 /* Handle tokens that refer to machine registers:
599 $ followed by a register name. */
600 i
= user_reg_map_name_to_regnum (parse_gdbarch
,
601 str
.ptr
+ 1, str
.length
- 1);
603 goto handle_register
;
605 /* Any names starting with $ are probably debugger internal variables. */
607 isym
= lookup_only_internalvar (copy_name (str
) + 1);
610 write_exp_elt_opcode (OP_INTERNALVAR
);
611 write_exp_elt_intern (isym
);
612 write_exp_elt_opcode (OP_INTERNALVAR
);
616 /* On some systems, such as HP-UX and hppa-linux, certain system routines
617 have names beginning with $ or $$. Check for those, first. */
619 sym
= lookup_symbol (copy_name (str
), (struct block
*) NULL
,
620 VAR_DOMAIN
, (int *) NULL
);
623 write_exp_elt_opcode (OP_VAR_VALUE
);
624 write_exp_elt_block (block_found
); /* set by lookup_symbol */
625 write_exp_elt_sym (sym
);
626 write_exp_elt_opcode (OP_VAR_VALUE
);
629 msym
= lookup_minimal_symbol (copy_name (str
), NULL
, NULL
);
632 write_exp_msymbol (msym
);
636 /* Any other names are assumed to be debugger internal variables. */
638 write_exp_elt_opcode (OP_INTERNALVAR
);
639 write_exp_elt_intern (create_internalvar (copy_name (str
) + 1));
640 write_exp_elt_opcode (OP_INTERNALVAR
);
643 write_exp_elt_opcode (OP_LAST
);
644 write_exp_elt_longcst ((LONGEST
) i
);
645 write_exp_elt_opcode (OP_LAST
);
648 write_exp_elt_opcode (OP_REGISTER
);
651 write_exp_string (str
);
652 write_exp_elt_opcode (OP_REGISTER
);
658 find_template_name_end (char *p
)
661 int just_seen_right
= 0;
662 int just_seen_colon
= 0;
663 int just_seen_space
= 0;
665 if (!p
|| (*p
!= '<'))
676 /* In future, may want to allow these?? */
679 depth
++; /* start nested template */
680 if (just_seen_colon
|| just_seen_right
|| just_seen_space
)
681 return 0; /* but not after : or :: or > or space */
684 if (just_seen_colon
|| just_seen_right
)
685 return 0; /* end a (nested?) template */
686 just_seen_right
= 1; /* but not after : or :: */
687 if (--depth
== 0) /* also disallow >>, insist on > > */
688 return ++p
; /* if outermost ended, return */
691 if (just_seen_space
|| (just_seen_colon
> 1))
692 return 0; /* nested class spec coming up */
693 just_seen_colon
++; /* we allow :: but not :::: */
698 if (!((*p
>= 'a' && *p
<= 'z') || /* allow token chars */
699 (*p
>= 'A' && *p
<= 'Z') ||
700 (*p
>= '0' && *p
<= '9') ||
701 (*p
== '_') || (*p
== ',') || /* commas for template args */
702 (*p
== '&') || (*p
== '*') || /* pointer and ref types */
703 (*p
== '(') || (*p
== ')') || /* function types */
704 (*p
== '[') || (*p
== ']'))) /* array types */
719 /* Return a null-terminated temporary copy of the name
720 of a string token. */
723 copy_name (struct stoken token
)
725 /* Make sure there's enough space for the token. */
726 if (namecopy_size
< token
.length
+ 1)
728 namecopy_size
= token
.length
+ 1;
729 namecopy
= xrealloc (namecopy
, token
.length
+ 1);
732 memcpy (namecopy
, token
.ptr
, token
.length
);
733 namecopy
[token
.length
] = 0;
738 /* Reverse an expression from suffix form (in which it is constructed)
739 to prefix form (in which we can conveniently print or execute it).
740 Ordinarily this always returns -1. However, if EXPOUT_LAST_STRUCT
741 is not -1 (i.e., we are trying to complete a field name), it will
742 return the index of the subexpression which is the left-hand-side
743 of the struct operation at EXPOUT_LAST_STRUCT. */
746 prefixify_expression (struct expression
*expr
)
748 int len
= sizeof (struct expression
) + EXP_ELEM_TO_BYTES (expr
->nelts
);
749 struct expression
*temp
;
750 int inpos
= expr
->nelts
, outpos
= 0;
752 temp
= (struct expression
*) alloca (len
);
754 /* Copy the original expression into temp. */
755 memcpy (temp
, expr
, len
);
757 return prefixify_subexp (temp
, expr
, inpos
, outpos
);
760 /* Return the number of exp_elements in the postfix subexpression
761 of EXPR whose operator is at index ENDPOS - 1 in EXPR. */
764 length_of_subexp (struct expression
*expr
, int endpos
)
768 operator_length (expr
, endpos
, &oplen
, &args
);
772 oplen
+= length_of_subexp (expr
, endpos
- oplen
);
779 /* Sets *OPLENP to the length of the operator whose (last) index is
780 ENDPOS - 1 in EXPR, and sets *ARGSP to the number of arguments that
784 operator_length (struct expression
*expr
, int endpos
, int *oplenp
, int *argsp
)
786 expr
->language_defn
->la_exp_desc
->operator_length (expr
, endpos
,
790 /* Default value for operator_length in exp_descriptor vectors. */
793 operator_length_standard (struct expression
*expr
, int endpos
,
794 int *oplenp
, int *argsp
)
798 enum f90_range_type range_type
;
802 error (_("?error in operator_length_standard"));
804 i
= (int) expr
->elts
[endpos
- 1].opcode
;
810 oplen
= longest_to_int (expr
->elts
[endpos
- 2].longconst
);
811 oplen
= 5 + BYTES_TO_EXP_ELEM (oplen
+ 1);
834 case OP_F77_UNDETERMINED_ARGLIST
:
836 args
= 1 + longest_to_int (expr
->elts
[endpos
- 2].longconst
);
840 oplen
= 4 + longest_to_int (expr
->elts
[endpos
- 2].longconst
);
844 case OP_OBJC_MSGCALL
: /* Objective C message (method) call */
846 args
= 1 + longest_to_int (expr
->elts
[endpos
- 2].longconst
);
861 case UNOP_MEMVAL_TLS
:
879 case STRUCTOP_STRUCT
:
886 case OP_OBJC_NSSTRING
: /* Objective C Foundation Class NSString constant */
887 case OP_OBJC_SELECTOR
: /* Objective C "@selector" pseudo-op */
889 oplen
= longest_to_int (expr
->elts
[endpos
- 2].longconst
);
890 oplen
= 4 + BYTES_TO_EXP_ELEM (oplen
+ 1);
894 oplen
= longest_to_int (expr
->elts
[endpos
- 2].longconst
);
895 oplen
= (oplen
+ HOST_CHAR_BIT
- 1) / HOST_CHAR_BIT
;
896 oplen
= 4 + BYTES_TO_EXP_ELEM (oplen
);
901 args
= longest_to_int (expr
->elts
[endpos
- 2].longconst
);
902 args
-= longest_to_int (expr
->elts
[endpos
- 3].longconst
);
908 case TERNOP_SLICE_COUNT
:
913 case MULTI_SUBSCRIPT
:
915 args
= 1 + longest_to_int (expr
->elts
[endpos
- 2].longconst
);
918 case BINOP_ASSIGN_MODIFY
:
932 range_type
= longest_to_int (expr
->elts
[endpos
- 2].longconst
);
935 case LOW_BOUND_DEFAULT
:
936 case HIGH_BOUND_DEFAULT
:
939 case BOTH_BOUND_DEFAULT
:
942 case NONE_BOUND_DEFAULT
:
950 args
= 1 + (i
< (int) BINOP_END
);
957 /* Copy the subexpression ending just before index INEND in INEXPR
958 into OUTEXPR, starting at index OUTBEG.
959 In the process, convert it from suffix to prefix form.
960 If EXPOUT_LAST_STRUCT is -1, then this function always returns -1.
961 Otherwise, it returns the index of the subexpression which is the
962 left-hand-side of the expression at EXPOUT_LAST_STRUCT. */
965 prefixify_subexp (struct expression
*inexpr
,
966 struct expression
*outexpr
, int inend
, int outbeg
)
972 enum exp_opcode opcode
;
975 operator_length (inexpr
, inend
, &oplen
, &args
);
977 /* Copy the final operator itself, from the end of the input
978 to the beginning of the output. */
980 memcpy (&outexpr
->elts
[outbeg
], &inexpr
->elts
[inend
],
981 EXP_ELEM_TO_BYTES (oplen
));
984 if (expout_last_struct
== inend
)
985 result
= outbeg
- oplen
;
987 /* Find the lengths of the arg subexpressions. */
988 arglens
= (int *) alloca (args
* sizeof (int));
989 for (i
= args
- 1; i
>= 0; i
--)
991 oplen
= length_of_subexp (inexpr
, inend
);
996 /* Now copy each subexpression, preserving the order of
997 the subexpressions, but prefixifying each one.
998 In this loop, inend starts at the beginning of
999 the expression this level is working on
1000 and marches forward over the arguments.
1001 outbeg does similarly in the output. */
1002 for (i
= 0; i
< args
; i
++)
1007 r
= prefixify_subexp (inexpr
, outexpr
, inend
, outbeg
);
1010 /* Return immediately. We probably have only parsed a
1011 partial expression, so we don't want to try to reverse
1012 the other operands. */
1021 /* This page contains the two entry points to this file. */
1023 /* Read an expression from the string *STRINGPTR points to,
1024 parse it, and return a pointer to a struct expression that we malloc.
1025 Use block BLOCK as the lexical context for variable names;
1026 if BLOCK is zero, use the block of the selected stack frame.
1027 Meanwhile, advance *STRINGPTR to point after the expression,
1028 at the first nonwhite character that is not part of the expression
1029 (possibly a null character).
1031 If COMMA is nonzero, stop if a comma is reached. */
1034 parse_exp_1 (char **stringptr
, struct block
*block
, int comma
)
1036 return parse_exp_in_context (stringptr
, block
, comma
, 0, NULL
);
1039 /* As for parse_exp_1, except that if VOID_CONTEXT_P, then
1040 no value is expected from the expression.
1041 OUT_SUBEXP is set when attempting to complete a field name; in this
1042 case it is set to the index of the subexpression on the
1043 left-hand-side of the struct op. If not doing such completion, it
1044 is left untouched. */
1046 static struct expression
*
1047 parse_exp_in_context (char **stringptr
, struct block
*block
, int comma
,
1048 int void_context_p
, int *out_subexp
)
1050 volatile struct gdb_exception except
;
1051 struct cleanup
*old_chain
;
1054 lexptr
= *stringptr
;
1058 type_stack_depth
= 0;
1059 expout_last_struct
= -1;
1061 comma_terminates
= comma
;
1063 if (lexptr
== 0 || *lexptr
== 0)
1064 error_no_arg (_("expression to compute"));
1066 old_chain
= make_cleanup (free_funcalls
, 0 /*ignore*/);
1069 expression_context_block
= block
;
1071 /* If no context specified, try using the current frame, if any. */
1072 if (!expression_context_block
)
1073 expression_context_block
= get_selected_block (&expression_context_pc
);
1075 expression_context_pc
= BLOCK_START (expression_context_block
);
1077 /* Fall back to using the current source static context, if any. */
1079 if (!expression_context_block
)
1081 struct symtab_and_line cursal
= get_current_source_symtab_and_line ();
1083 expression_context_block
1084 = BLOCKVECTOR_BLOCK (BLOCKVECTOR (cursal
.symtab
), STATIC_BLOCK
);
1085 if (expression_context_block
)
1086 expression_context_pc
= BLOCK_START (expression_context_block
);
1091 expout
= (struct expression
*)
1092 xmalloc (sizeof (struct expression
) + EXP_ELEM_TO_BYTES (expout_size
));
1093 expout
->language_defn
= current_language
;
1094 expout
->gdbarch
= get_current_arch ();
1096 TRY_CATCH (except
, RETURN_MASK_ALL
)
1098 if (current_language
->la_parser ())
1099 current_language
->la_error (NULL
);
1101 if (except
.reason
< 0)
1103 if (! in_parse_field
)
1106 throw_exception (except
);
1110 discard_cleanups (old_chain
);
1112 /* Record the actual number of expression elements, and then
1113 reallocate the expression memory so that we free up any
1116 expout
->nelts
= expout_ptr
;
1117 expout
= (struct expression
*)
1118 xrealloc ((char *) expout
,
1119 sizeof (struct expression
) + EXP_ELEM_TO_BYTES (expout_ptr
));;
1121 /* Convert expression from postfix form as generated by yacc
1122 parser, to a prefix form. */
1124 if (expressiondebug
)
1125 dump_raw_expression (expout
, gdb_stdlog
,
1126 "before conversion to prefix form");
1128 subexp
= prefixify_expression (expout
);
1130 *out_subexp
= subexp
;
1132 current_language
->la_post_parser (&expout
, void_context_p
);
1134 if (expressiondebug
)
1135 dump_prefix_expression (expout
, gdb_stdlog
);
1137 *stringptr
= lexptr
;
1141 /* Parse STRING as an expression, and complain if this fails
1142 to use up all of the contents of STRING. */
1145 parse_expression (char *string
)
1147 struct expression
*exp
;
1148 exp
= parse_exp_1 (&string
, 0, 0);
1150 error (_("Junk after end of expression."));
1154 /* Parse STRING as an expression. If parsing ends in the middle of a
1155 field reference, return the type of the left-hand-side of the
1156 reference; furthermore, if the parsing ends in the field name,
1157 return the field name in *NAME. In all other cases, return NULL.
1158 Returned non-NULL *NAME must be freed by the caller. */
1161 parse_field_expression (char *string
, char **name
)
1163 struct expression
*exp
= NULL
;
1166 volatile struct gdb_exception except
;
1168 TRY_CATCH (except
, RETURN_MASK_ALL
)
1171 exp
= parse_exp_in_context (&string
, 0, 0, 0, &subexp
);
1174 if (except
.reason
< 0 || ! exp
)
1176 if (expout_last_struct
== -1)
1182 *name
= extract_field_op (exp
, &subexp
);
1188 /* (*NAME) is a part of the EXP memory block freed below. */
1189 *name
= xstrdup (*name
);
1191 val
= evaluate_subexpression_type (exp
, subexp
);
1194 return value_type (val
);
1197 /* A post-parser that does nothing */
1200 null_post_parser (struct expression
**exp
, int void_context_p
)
1204 /* Stuff for maintaining a stack of types. Currently just used by C, but
1205 probably useful for any language which declares its types "backwards". */
1208 check_type_stack_depth (void)
1210 if (type_stack_depth
== type_stack_size
)
1212 type_stack_size
*= 2;
1213 type_stack
= (union type_stack_elt
*)
1214 xrealloc ((char *) type_stack
, type_stack_size
* sizeof (*type_stack
));
1219 push_type (enum type_pieces tp
)
1221 check_type_stack_depth ();
1222 type_stack
[type_stack_depth
++].piece
= tp
;
1226 push_type_int (int n
)
1228 check_type_stack_depth ();
1229 type_stack
[type_stack_depth
++].int_val
= n
;
1233 push_type_address_space (char *string
)
1235 push_type_int (address_space_name_to_int (parse_gdbarch
, string
));
1241 if (type_stack_depth
)
1242 return type_stack
[--type_stack_depth
].piece
;
1249 if (type_stack_depth
)
1250 return type_stack
[--type_stack_depth
].int_val
;
1251 /* "Can't happen". */
1255 /* Pop the type stack and return the type which corresponds to FOLLOW_TYPE
1256 as modified by all the stuff on the stack. */
1258 follow_types (struct type
*follow_type
)
1262 int make_volatile
= 0;
1263 int make_addr_space
= 0;
1267 switch (pop_type ())
1272 follow_type
= make_cv_type (make_const
,
1273 TYPE_VOLATILE (follow_type
),
1276 follow_type
= make_cv_type (TYPE_CONST (follow_type
),
1279 if (make_addr_space
)
1280 follow_type
= make_type_with_address_space (follow_type
,
1282 make_const
= make_volatile
= 0;
1283 make_addr_space
= 0;
1291 case tp_space_identifier
:
1292 make_addr_space
= pop_type_int ();
1295 follow_type
= lookup_pointer_type (follow_type
);
1297 follow_type
= make_cv_type (make_const
,
1298 TYPE_VOLATILE (follow_type
),
1301 follow_type
= make_cv_type (TYPE_CONST (follow_type
),
1304 if (make_addr_space
)
1305 follow_type
= make_type_with_address_space (follow_type
,
1307 make_const
= make_volatile
= 0;
1308 make_addr_space
= 0;
1311 follow_type
= lookup_reference_type (follow_type
);
1313 follow_type
= make_cv_type (make_const
,
1314 TYPE_VOLATILE (follow_type
),
1317 follow_type
= make_cv_type (TYPE_CONST (follow_type
),
1320 if (make_addr_space
)
1321 follow_type
= make_type_with_address_space (follow_type
,
1323 make_const
= make_volatile
= 0;
1324 make_addr_space
= 0;
1327 array_size
= pop_type_int ();
1328 /* FIXME-type-allocation: need a way to free this type when we are
1331 lookup_array_range_type (follow_type
,
1332 0, array_size
>= 0 ? array_size
- 1 : 0);
1334 TYPE_ARRAY_UPPER_BOUND_IS_UNDEFINED (follow_type
) = 1;
1337 /* FIXME-type-allocation: need a way to free this type when we are
1339 follow_type
= lookup_function_type (follow_type
);
1345 /* This function avoids direct calls to fprintf
1346 in the parser generated debug code. */
1348 parser_fprintf (FILE *x
, const char *y
, ...)
1353 vfprintf_unfiltered (gdb_stderr
, y
, args
);
1356 fprintf_unfiltered (gdb_stderr
, " Unknown FILE used.\n");
1357 vfprintf_unfiltered (gdb_stderr
, y
, args
);
1363 _initialize_parse (void)
1365 type_stack_size
= 80;
1366 type_stack_depth
= 0;
1367 type_stack
= (union type_stack_elt
*)
1368 xmalloc (type_stack_size
* sizeof (*type_stack
));
1370 add_setshow_zinteger_cmd ("expression", class_maintenance
,
1371 &expressiondebug
, _("\
1372 Set expression debugging."), _("\
1373 Show expression debugging."), _("\
1374 When non-zero, the internal representation of expressions will be printed."),
1376 show_expressiondebug
,
1377 &setdebuglist
, &showdebuglist
);