1 /* Definitions for expressions stored in reversed prefix form, for GDB.
2 Copyright 1986, 1989, 1992, 1994, 2000 Free Software Foundation, Inc.
4 This file is part of GDB.
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2 of the License, or
9 (at your option) any later version.
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program; if not, write to the Free Software
18 Foundation, Inc., 59 Temple Place - Suite 330,
19 Boston, MA 02111-1307, USA. */
21 #if !defined (EXPRESSION_H)
22 #define EXPRESSION_H 1
25 #include "symtab.h" /* Needed for "struct block" type. */
26 #include "doublest.h" /* Needed for DOUBLEST. */
29 /* Definitions for saved C expressions. */
31 /* An expression is represented as a vector of union exp_element's.
32 Each exp_element is an opcode, except that some opcodes cause
33 the following exp_element to be treated as a long or double constant
34 or as a variable. The opcodes are obeyed, using a stack for temporaries.
35 The value is left on the temporary stack at the end. */
37 /* When it is necessary to include a string,
38 it can occupy as many exp_elements as it needs.
39 We find the length of the string using strlen,
40 divide to find out how many exp_elements are used up,
41 and skip that many. Strings, like numbers, are indicated
42 by the preceding opcode. */
46 /* Used when it's necessary to pass an opcode which will be ignored,
47 or to catch uninitialized values. */
50 /* BINOP_... operate on two values computed by following subexpressions,
51 replacing them by one result value. They take no immediate arguments. */
58 BINOP_MOD
, /* mod (Knuth 1.2.4) */
61 BINOP_LOGICAL_AND
, /* && */
62 BINOP_LOGICAL_OR
, /* || */
63 BINOP_BITWISE_AND
, /* & */
64 BINOP_BITWISE_IOR
, /* | */
65 BINOP_BITWISE_XOR
, /* ^ */
67 BINOP_NOTEQUAL
, /* != */
75 BINOP_SUBSCRIPT
, /* x[y] */
76 BINOP_EXP
, /* Exponentiation */
83 /* STRUCTOP_MEMBER is used for pointer-to-member constructs.
84 X . * Y translates into X STRUCTOP_MEMBER Y. */
87 /* STRUCTOP_MPTR is used for pointer-to-member constructs
88 when X is a pointer instead of an aggregate. */
93 /* For Modula-2 integer division DIV */
96 BINOP_ASSIGN_MODIFY
, /* +=, -=, *=, and so on.
97 The following exp_element is another opcode,
98 a BINOP_, saying how to modify.
99 Then comes another BINOP_ASSIGN_MODIFY,
100 making three exp_elements in total. */
102 /* Modula-2 standard (binary) procedures */
107 /* Concatenate two operands, such as character strings or bitstrings.
108 If the first operand is a integer expression, then it means concatenate
109 the second operand with itself that many times. */
112 /* For (OBSOLETE) Chill (OBSOLETE) and Pascal. */
113 BINOP_IN
, /* Returns 1 iff ARG1 IN ARG2. */
115 /* This is the "colon operator" used various places in (OBSOLETE)
119 /* This must be the highest BINOP_ value, for expprint.c. */
122 /* Operates on three values computed by following subexpressions. */
123 TERNOP_COND
, /* ?: */
125 /* A sub-string/sub-array. (OBSOLETE) Chill (OBSOLETE) syntax:
126 OP1(OP2:OP3). Return elements OP2 through OP3 of OP1. */
129 /* A sub-string/sub-array. (OBSOLETE) Chill (OBSOLETE) syntax:
130 OP1(OP2 UP OP3). Return OP3 elements of OP1, starting with
134 /* Multidimensional subscript operator, such as Modula-2 x[a,b,...].
135 The dimensionality is encoded in the operator, like the number of
136 function arguments in OP_FUNCALL, I.E. <OP><dimension><OP>.
137 The value of the first following subexpression is subscripted
138 by each of the next following subexpressions, one per dimension. */
141 /* The OP_... series take immediate following arguments.
142 After the arguments come another OP_... (the same one)
143 so that the grouping can be recognized from the end. */
145 /* OP_LONG is followed by a type pointer in the next exp_element
146 and the long constant value in the following exp_element.
147 Then comes another OP_LONG.
148 Thus, the operation occupies four exp_elements. */
151 /* OP_DOUBLE is similar but takes a DOUBLEST constant instead of a long. */
154 /* OP_VAR_VALUE takes one struct block * in the following element,
155 and one struct symbol * in the following exp_element, followed by
156 another OP_VAR_VALUE, making four exp_elements. If the block is
157 non-NULL, evaluate the symbol relative to the innermost frame
158 executing in that block; if the block is NULL use the selected frame. */
161 /* OP_LAST is followed by an integer in the next exp_element.
162 The integer is zero for the last value printed,
163 or it is the absolute number of a history element.
164 With another OP_LAST at the end, this makes three exp_elements. */
167 /* OP_REGISTER is followed by an integer in the next exp_element.
168 This is the number of a register to fetch (as an int).
169 With another OP_REGISTER at the end, this makes three exp_elements. */
172 /* OP_INTERNALVAR is followed by an internalvar ptr in the next exp_element.
173 With another OP_INTERNALVAR at the end, this makes three exp_elements. */
176 /* OP_FUNCALL is followed by an integer in the next exp_element.
177 The integer is the number of args to the function call.
178 That many plus one values from following subexpressions
179 are used, the first one being the function.
180 The integer is followed by a repeat of OP_FUNCALL,
181 making three exp_elements. */
184 /* OP_MSGCALL is followed by a string in the next exp_element and then an
185 integer. The string is the selector string. The integer is the number
186 of arguments to the message call. That many plus one values are used,
187 the first one being the object pointer. This is an Objective C message */
190 /* This is EXACTLY like OP_FUNCALL but is semantically different.
191 In F77, array subscript expressions, substring expressions
192 and function calls are all exactly the same syntactically. They may
193 only be dismabiguated at runtime. Thus this operator, which
194 indicates that we have found something of the form <name> ( <stuff> ) */
195 OP_F77_UNDETERMINED_ARGLIST
,
197 /* The following OP is a special one, it introduces a F77 complex
198 literal. It is followed by exactly two args that are doubles. */
201 /* OP_STRING represents a string constant.
202 Its format is the same as that of a STRUCTOP, but the string
203 data is just made into a string constant when the operation
207 /* OP_BITSTRING represents a packed bitstring constant.
208 Its format is the same as that of a STRUCTOP, but the bitstring
209 data is just made into a bitstring constant when the operation
213 /* OP_ARRAY creates an array constant out of the following subexpressions.
214 It is followed by two exp_elements, the first containing an integer
215 that is the lower bound of the array and the second containing another
216 integer that is the upper bound of the array. The second integer is
217 followed by a repeat of OP_ARRAY, making four exp_elements total.
218 The bounds are used to compute the number of following subexpressions
219 to consume, as well as setting the bounds in the created array constant.
220 The type of the elements is taken from the type of the first subexp,
221 and they must all match. */
224 /* UNOP_CAST is followed by a type pointer in the next exp_element.
225 With another UNOP_CAST at the end, this makes three exp_elements.
226 It casts the value of the following subexpression. */
229 /* UNOP_MEMVAL is followed by a type pointer in the next exp_element
230 With another UNOP_MEMVAL at the end, this makes three exp_elements.
231 It casts the contents of the word addressed by the value of the
232 following subexpression. */
235 /* UNOP_... operate on one value from a following subexpression
236 and replace it with a result. They take no immediate arguments. */
238 UNOP_NEG
, /* Unary - */
239 UNOP_LOGICAL_NOT
, /* Unary ! */
240 UNOP_COMPLEMENT
, /* Unary ~ */
241 UNOP_IND
, /* Unary * */
242 UNOP_ADDR
, /* Unary & */
243 UNOP_PREINCREMENT
, /* ++ before an expression */
244 UNOP_POSTINCREMENT
, /* ++ after an expression */
245 UNOP_PREDECREMENT
, /* -- before an expression */
246 UNOP_POSTDECREMENT
, /* -- after an expression */
247 UNOP_SIZEOF
, /* Unary sizeof (followed by expression) */
249 UNOP_PLUS
, /* Unary plus */
251 UNOP_CAP
, /* Modula-2 standard (unary) procedures */
262 /* (OBSOLETE) Chill (OBSOLETE) builtin functions. */
263 UNOP_LOWER
, UNOP_UPPER
, UNOP_LENGTH
, UNOP_CARD
, UNOP_CHMAX
, UNOP_CHMIN
,
265 OP_BOOL
, /* Modula-2 builtin BOOLEAN type */
266 OP_M2_STRING
, /* Modula-2 string constants */
268 /* STRUCTOP_... operate on a value from a following subexpression
269 by extracting a structure component specified by a string
270 that appears in the following exp_elements (as many as needed).
271 STRUCTOP_STRUCT is used for "." and STRUCTOP_PTR for "->".
272 They differ only in the error message given in case the value is
273 not suitable or the structure component specified is not found.
275 The length of the string follows the opcode, followed by
276 BYTES_TO_EXP_ELEM(length) elements containing the data of the
277 string, followed by the length again and the opcode again. */
283 OP_THIS is just a placeholder for the class instance variable.
284 It just comes in a tight (OP_THIS, OP_THIS) pair. */
287 /* Objective C: "@selector" pseudo-operator */
290 /* Objective C: OP_SELF is just a placeholder for the class instance
291 variable. It just comes in a tight (OP_SELF, OP_SELF) pair. */
294 /* OP_SCOPE surrounds a type name and a field name. The type
295 name is encoded as one element, but the field name stays as
296 a string, which, of course, is variable length. */
299 /* Used to represent named structure field values in brace
300 initializers (or tuples as they are called in (OBSOLETE) Chill
303 The gcc C syntax is NAME:VALUE or .NAME=VALUE, the (OBSOLETE)
304 Chill (OBSOLETE) syntax is .NAME:VALUE. Multiple labels (as in
305 the (OBSOLETE) Chill (OBSOLETE) syntax .NAME1,.NAME2:VALUE) is
306 represented as if it were .NAME1:(.NAME2:VALUE) (though that is
307 not valid (OBSOLETE) Chill (OBSOLETE) syntax).
309 The NAME is represented as for STRUCTOP_STRUCT; VALUE follows. */
312 /* OP_TYPE is for parsing types, and used with the "ptype" command
313 so we can look up types that are qualified by scope, either with
314 the GDB "::" operator, or the Modula-2 '.' operator. */
317 /* An un-looked-up identifier. */
320 /* An unparsed expression. Used for Scheme (for now at least) */
323 /* An Objective C Foundation Class NSString constant */
329 enum exp_opcode opcode
;
330 struct symbol
*symbol
;
332 DOUBLEST doubleconst
;
333 /* Really sizeof (union exp_element) characters (or less for the last
334 element of a string). */
337 struct internalvar
*internalvar
;
343 const struct language_defn
*language_defn
; /* language it was entered in */
345 union exp_element elts
[1];
348 /* Macros for converting between number of expression elements and bytes
349 to store that many expression elements. */
351 #define EXP_ELEM_TO_BYTES(elements) \
352 ((elements) * sizeof (union exp_element))
353 #define BYTES_TO_EXP_ELEM(bytes) \
354 (((bytes) + sizeof (union exp_element) - 1) / sizeof (union exp_element))
358 extern struct expression
*parse_expression (char *);
360 extern struct expression
*parse_exp_1 (char **, struct block
*, int);
362 /* The innermost context required by the stack and register variables
363 we've encountered so far. To use this, set it to NULL, then call
364 parse_<whatever>, then look at it. */
365 extern struct block
*innermost_block
;
369 /* Values of NOSIDE argument to evaluate_subexp. */
374 EVAL_SKIP
, /* Only effect is to increment pos. */
375 EVAL_AVOID_SIDE_EFFECTS
/* Don't modify any variables or
376 call any functions. The value
377 returned will have the correct
378 type, and will have an
379 approximately correct lvalue
380 type (inaccuracy: anything that is
381 listed as being in a register in
382 the function in which it was
383 declared will be lval_register). */
386 extern struct value
*evaluate_subexp_standard
387 (struct type
*, struct expression
*, int *, enum noside
);
389 /* From expprint.c */
391 extern void print_expression (struct expression
*, struct ui_file
*);
393 extern char *op_string (enum exp_opcode
);
395 extern void dump_prefix_expression (struct expression
*,
398 extern void dump_postfix_expression (struct expression
*,
402 #endif /* !defined (EXPRESSION_H) */