1 /* Definitions for expressions stored in reversed prefix form, for GDB.
2 Copyright 1986, 1989, 1992, 1994 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., 675 Mass Ave, Cambridge, MA 02139, USA. */
20 #if !defined (EXPRESSION_H)
21 #define EXPRESSION_H 1
26 struct block; /* Forward declaration for prototypes */
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 */
84 /* STRUCTOP_MEMBER is used for pointer-to-member constructs.
85 X . * Y translates into X STRUCTOP_MEMBER Y. */
88 /* STRUCTOP_MPTR is used for pointer-to-member constructs
89 when X is a pointer instead of an aggregate. */
94 /* For Modula-2 integer division DIV */
97 BINOP_ASSIGN_MODIFY, /* +=, -=, *=, and so on.
98 The following exp_element is another opcode,
99 a BINOP_, saying how to modify.
100 Then comes another BINOP_ASSIGN_MODIFY,
101 making three exp_elements in total. */
103 /* Modula-2 standard (binary) procedures */
108 /* Concatenate two operands, such as character strings or bitstrings.
109 If the first operand is a integer expression, then it means concatenate
110 the second operand with itself that many times. */
113 /* For Chill and Pascal. */
114 BINOP_IN, /* Returns 1 iff ARG1 IN ARG2. */
116 /* This must be the highest BINOP_ value, for expprint.c. */
119 /* Operates on three values computed by following subexpressions. */
120 TERNOP_COND, /* ?: */
122 /* A sub-string/sub-array. Chill syntax: OP1(OP2:OP3).
123 Return elements OP2 through OP3 of OP1. */
126 /* A sub-string/sub-array. Chill syntax: OP1(OP2 UP OP3).
127 Return OP3 elements of OP1, starting with element OP2. */
130 /* Multidimensional subscript operator, such as Modula-2 x[a,b,...].
131 The dimensionality is encoded in the operator, like the number of
132 function arguments in OP_FUNCALL, I.E. <OP><dimension><OP>.
133 The value of the first following subexpression is subscripted
134 by each of the next following subexpressions, one per dimension. */
137 /* The OP_... series take immediate following arguments.
138 After the arguments come another OP_... (the same one)
139 so that the grouping can be recognized from the end. */
141 /* OP_LONG is followed by a type pointer in the next exp_element
142 and the long constant value in the following exp_element.
143 Then comes another OP_LONG.
144 Thus, the operation occupies four exp_elements. */
147 /* OP_DOUBLE is similar but takes a double constant instead of a long. */
150 /* OP_VAR_VALUE takes one struct block * in the following element,
151 and one struct symbol * in the following exp_element, followed by
152 another OP_VAR_VALUE, making four exp_elements. If the block is
153 non-NULL, evaluate the symbol relative to the innermost frame
154 executing in that block; if the block is NULL use the selected frame. */
157 /* OP_LAST is followed by an integer in the next exp_element.
158 The integer is zero for the last value printed,
159 or it is the absolute number of a history element.
160 With another OP_LAST at the end, this makes three exp_elements. */
163 /* OP_REGISTER is followed by an integer in the next exp_element.
164 This is the number of a register to fetch (as an int).
165 With another OP_REGISTER at the end, this makes three exp_elements. */
168 /* OP_INTERNALVAR is followed by an internalvar ptr in the next exp_element.
169 With another OP_INTERNALVAR at the end, this makes three exp_elements. */
172 /* OP_FUNCALL is followed by an integer in the next exp_element.
173 The integer is the number of args to the function call.
174 That many plus one values from following subexpressions
175 are used, the first one being the function.
176 The integer is followed by a repeat of OP_FUNCALL,
177 making three exp_elements. */
180 /* This is EXACTLY like OP_FUNCALL but is semantically different.
181 In F77, array subscript expressions, substring expressions
182 and function calls are all exactly the same syntactically. They may
183 only be dismabiguated at runtime. Thus this operator, which
184 indicates that we have found something of the form <name> ( <stuff> ) */
185 OP_F77_UNDETERMINED_ARGLIST,
187 /* The following OP is a special one, it introduces a F77 complex
188 literal. It is followed by exactly two args that are doubles. */
191 /* OP_STRING represents a string constant.
192 Its format is the same as that of a STRUCTOP, but the string
193 data is just made into a string constant when the operation
197 /* OP_BITSTRING represents a packed bitstring constant.
198 Its format is the same as that of a STRUCTOP, but the bitstring
199 data is just made into a bitstring constant when the operation
203 /* OP_ARRAY creates an array constant out of the following subexpressions.
204 It is followed by two exp_elements, the first containing an integer
205 that is the lower bound of the array and the second containing another
206 integer that is the upper bound of the array. The second integer is
207 followed by a repeat of OP_ARRAY, making four exp_elements total.
208 The bounds are used to compute the number of following subexpressions
209 to consume, as well as setting the bounds in the created array constant.
210 The type of the elements is taken from the type of the first subexp,
211 and they must all match. */
214 /* UNOP_CAST is followed by a type pointer in the next exp_element.
215 With another UNOP_CAST at the end, this makes three exp_elements.
216 It casts the value of the following subexpression. */
219 /* UNOP_MEMVAL is followed by a type pointer in the next exp_element
220 With another UNOP_MEMVAL at the end, this makes three exp_elements.
221 It casts the contents of the word addressed by the value of the
222 following subexpression. */
225 /* UNOP_... operate on one value from a following subexpression
226 and replace it with a result. They take no immediate arguments. */
228 UNOP_NEG, /* Unary - */
229 UNOP_LOGICAL_NOT, /* Unary ! */
230 UNOP_COMPLEMENT, /* Unary ~ */
231 UNOP_IND, /* Unary * */
232 UNOP_ADDR, /* Unary & */
233 UNOP_PREINCREMENT, /* ++ before an expression */
234 UNOP_POSTINCREMENT, /* ++ after an expression */
235 UNOP_PREDECREMENT, /* -- before an expression */
236 UNOP_POSTDECREMENT, /* -- after an expression */
237 UNOP_SIZEOF, /* Unary sizeof (followed by expression) */
239 UNOP_PLUS, /* Unary plus */
241 UNOP_CAP, /* Modula-2 standard (unary) procedures */
252 OP_BOOL, /* Modula-2 builtin BOOLEAN type */
253 OP_M2_STRING, /* Modula-2 string constants */
255 /* STRUCTOP_... operate on a value from a following subexpression
256 by extracting a structure component specified by a string
257 that appears in the following exp_elements (as many as needed).
258 STRUCTOP_STRUCT is used for "." and STRUCTOP_PTR for "->".
259 They differ only in the error message given in case the value is
260 not suitable or the structure component specified is not found.
262 The length of the string follows the opcode, followed by
263 BYTES_TO_EXP_ELEM(length) elements containing the data of the
264 string, followed by the length again and the opcode again. */
270 /* OP_THIS is just a placeholder for the class instance variable.
271 It just comes in a tight (OP_THIS, OP_THIS) pair. */
274 /* OP_SCOPE surrounds a type name and a field name. The type
275 name is encoded as one element, but the field name stays as
276 a string, which, of course, is variable length. */
279 /* Used to represent named structure field values in brace initializers
280 (or tuples as they are called in Chill).
281 The gcc C syntax is NAME:VALUE or .NAME=VALUE, the Chill syntax is
282 .NAME:VALUE. Multiple labels (as in the Chill syntax
283 .NAME1,.NAME2:VALUE) is represented as if it were
284 .NAME1:(.NAME2:VALUE) (though that is not valid Chill syntax).
286 The NAME is represented as for STRUCTOP_STRUCT; VALUE follows. */
289 /* OP_TYPE is for parsing types, and used with the "ptype" command
290 so we can look up types that are qualified by scope, either with
291 the GDB "::" operator, or the Modula-2 '.' operator. */
297 enum exp_opcode opcode;
298 struct symbol *symbol;
301 /* Really sizeof (union exp_element) characters (or less for the last
302 element of a string). */
305 struct internalvar *internalvar;
311 const struct language_defn *language_defn; /* language it was entered in */
313 union exp_element elts[1];
316 /* Macros for converting between number of expression elements and bytes
317 to store that many expression elements. */
319 #define EXP_ELEM_TO_BYTES(elements) \
320 ((elements) * sizeof (union exp_element))
321 #define BYTES_TO_EXP_ELEM(bytes) \
322 (((bytes) + sizeof (union exp_element) - 1) / sizeof (union exp_element))
326 extern struct expression *parse_expression PARAMS ((char *));
328 extern struct expression *parse_exp_1 PARAMS ((char **, struct block *, int));
330 /* The innermost context required by the stack and register variables
331 we've encountered so far. To use this, set it to NULL, then call
332 parse_<whatever>, then look at it. */
333 extern struct block *innermost_block;
337 /* Values of NOSIDE argument to eval_subexp. */
342 EVAL_SKIP, /* Only effect is to increment pos. */
343 EVAL_AVOID_SIDE_EFFECTS /* Don't modify any variables or
344 call any functions. The value
345 returned will have the correct
346 type, and will have an
347 approximately correct lvalue
348 type (inaccuracy: anything that is
349 listed as being in a register in
350 the function in which it was
351 declared will be lval_register). */
354 extern struct value* evaluate_subexp_standard
355 PARAMS ((struct type *, struct expression *, int*, enum noside));
357 extern value_ptr evaluate_subexp_with_coercion PARAMS ((struct expression *,
358 int *, enum noside));
360 /* From expprint.c */
362 extern void print_expression PARAMS ((struct expression *, GDB_FILE *));
364 extern char *op_string PARAMS ((enum exp_opcode));
366 /* To enable dumping of all parsed expressions in a human readable
367 form, define DEBUG_EXPRESSIONS. This is a compile time constant
368 at the moment, since it's not clear that this feature is important
369 enough to include by default. */
371 #ifdef DEBUG_EXPRESSIONS
372 extern void dump_expression PARAMS ((struct expression *, GDB_FILE *, char *));
373 #define DUMP_EXPRESSION(exp,file,note) dump_expression ((exp), (file), (note))
375 #define DUMP_EXPRESSION(exp,file,note) /* Null expansion */
376 #endif /* DEBUG_EXPRESSIONS */
378 #endif /* !defined (EXPRESSION_H) */