1 /* Definitions for expressions stored in reversed prefix form, for GDB. 2 3 Copyright 1986, 1989, 1992, 1994, 2000, 2003 Free Software 4 Foundation, Inc. 5 6 This file is part of GDB. 7 8 This program is free software; you can redistribute it and/or modify 9 it under the terms of the GNU General Public License as published by 10 the Free Software Foundation; either version 2 of the License, or 11 (at your option) any later version. 12 13 This program is distributed in the hope that it will be useful, 14 but WITHOUT ANY WARRANTY; without even the implied warranty of 15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 GNU General Public License for more details. 17 18 You should have received a copy of the GNU General Public License 19 along with this program; if not, write to the Free Software 20 Foundation, Inc., 59 Temple Place - Suite 330, 21 Boston, MA 02111-1307, USA. */ 22 23 #if !defined (EXPRESSION_H) 24 #define EXPRESSION_H 1 25 26 27 #include "symtab.h" /* Needed for "struct block" type. */ 28 #include "doublest.h" /* Needed for DOUBLEST. */ 29 30 31 /* Definitions for saved C expressions. */ 32 33 /* An expression is represented as a vector of union exp_element's. 34 Each exp_element is an opcode, except that some opcodes cause 35 the following exp_element to be treated as a long or double constant 36 or as a variable. The opcodes are obeyed, using a stack for temporaries. 37 The value is left on the temporary stack at the end. */ 38 39 /* When it is necessary to include a string, 40 it can occupy as many exp_elements as it needs. 41 We find the length of the string using strlen, 42 divide to find out how many exp_elements are used up, 43 and skip that many. Strings, like numbers, are indicated 44 by the preceding opcode. */ 45 46 enum exp_opcode 47 { 48 /* Used when it's necessary to pass an opcode which will be ignored, 49 or to catch uninitialized values. */ 50 OP_NULL, 51 52 /* BINOP_... operate on two values computed by following subexpressions, 53 replacing them by one result value. They take no immediate arguments. */ 54 55 BINOP_ADD, /* + */ 56 BINOP_SUB, /* - */ 57 BINOP_MUL, /* * */ 58 BINOP_DIV, /* / */ 59 BINOP_REM, /* % */ 60 BINOP_MOD, /* mod (Knuth 1.2.4) */ 61 BINOP_LSH, /* << */ 62 BINOP_RSH, /* >> */ 63 BINOP_LOGICAL_AND, /* && */ 64 BINOP_LOGICAL_OR, /* || */ 65 BINOP_BITWISE_AND, /* & */ 66 BINOP_BITWISE_IOR, /* | */ 67 BINOP_BITWISE_XOR, /* ^ */ 68 BINOP_EQUAL, /* == */ 69 BINOP_NOTEQUAL, /* != */ 70 BINOP_LESS, /* < */ 71 BINOP_GTR, /* > */ 72 BINOP_LEQ, /* <= */ 73 BINOP_GEQ, /* >= */ 74 BINOP_REPEAT, /* @ */ 75 BINOP_ASSIGN, /* = */ 76 BINOP_COMMA, /* , */ 77 BINOP_SUBSCRIPT, /* x[y] */ 78 BINOP_EXP, /* Exponentiation */ 79 80 /* C++. */ 81 82 BINOP_MIN, /* <? */ 83 BINOP_MAX, /* >? */ 84 85 /* STRUCTOP_MEMBER is used for pointer-to-member constructs. 86 X . * Y translates into X STRUCTOP_MEMBER Y. */ 87 STRUCTOP_MEMBER, 88 89 /* STRUCTOP_MPTR is used for pointer-to-member constructs 90 when X is a pointer instead of an aggregate. */ 91 STRUCTOP_MPTR, 92 93 /* end of C++. */ 94 95 /* For Modula-2 integer division DIV */ 96 BINOP_INTDIV, 97 98 BINOP_ASSIGN_MODIFY, /* +=, -=, *=, and so on. 99 The following exp_element is another opcode, 100 a BINOP_, saying how to modify. 101 Then comes another BINOP_ASSIGN_MODIFY, 102 making three exp_elements in total. */ 103 104 /* Modula-2 standard (binary) procedures */ 105 BINOP_VAL, 106 BINOP_INCL, 107 BINOP_EXCL, 108 109 /* Concatenate two operands, such as character strings or bitstrings. 110 If the first operand is a integer expression, then it means concatenate 111 the second operand with itself that many times. */ 112 BINOP_CONCAT, 113 114 /* For (the deleted) Chill and Pascal. */ 115 BINOP_IN, /* Returns 1 iff ARG1 IN ARG2. */ 116 117 /* This is the "colon operator" used various places in (the 118 deleted) Chill. */ 119 BINOP_RANGE, 120 121 /* This must be the highest BINOP_ value, for expprint.c. */ 122 BINOP_END, 123 124 /* Operates on three values computed by following subexpressions. */ 125 TERNOP_COND, /* ?: */ 126 127 /* A sub-string/sub-array. (the deleted) Chill syntax: 128 OP1(OP2:OP3). Return elements OP2 through OP3 of OP1. */ 129 TERNOP_SLICE, 130 131 /* A sub-string/sub-array. (The deleted) Chill syntax: OP1(OP2 UP 132 OP3). Return OP3 elements of OP1, starting with element 133 OP2. */ 134 TERNOP_SLICE_COUNT, 135 136 /* Multidimensional subscript operator, such as Modula-2 x[a,b,...]. 137 The dimensionality is encoded in the operator, like the number of 138 function arguments in OP_FUNCALL, I.E. <OP><dimension><OP>. 139 The value of the first following subexpression is subscripted 140 by each of the next following subexpressions, one per dimension. */ 141 MULTI_SUBSCRIPT, 142 143 /* The OP_... series take immediate following arguments. 144 After the arguments come another OP_... (the same one) 145 so that the grouping can be recognized from the end. */ 146 147 /* OP_LONG is followed by a type pointer in the next exp_element 148 and the long constant value in the following exp_element. 149 Then comes another OP_LONG. 150 Thus, the operation occupies four exp_elements. */ 151 OP_LONG, 152 153 /* OP_DOUBLE is similar but takes a DOUBLEST constant instead of a long. */ 154 OP_DOUBLE, 155 156 /* OP_VAR_VALUE takes one struct block * in the following element, 157 and one struct symbol * in the following exp_element, followed by 158 another OP_VAR_VALUE, making four exp_elements. If the block is 159 non-NULL, evaluate the symbol relative to the innermost frame 160 executing in that block; if the block is NULL use the selected frame. */ 161 OP_VAR_VALUE, 162 163 /* OP_LAST is followed by an integer in the next exp_element. 164 The integer is zero for the last value printed, 165 or it is the absolute number of a history element. 166 With another OP_LAST at the end, this makes three exp_elements. */ 167 OP_LAST, 168 169 /* OP_REGISTER is followed by an integer in the next exp_element. 170 This is the number of a register to fetch (as an int). 171 With another OP_REGISTER at the end, this makes three exp_elements. */ 172 OP_REGISTER, 173 174 /* OP_INTERNALVAR is followed by an internalvar ptr in the next exp_element. 175 With another OP_INTERNALVAR at the end, this makes three exp_elements. */ 176 OP_INTERNALVAR, 177 178 /* OP_FUNCALL is followed by an integer in the next exp_element. 179 The integer is the number of args to the function call. 180 That many plus one values from following subexpressions 181 are used, the first one being the function. 182 The integer is followed by a repeat of OP_FUNCALL, 183 making three exp_elements. */ 184 OP_FUNCALL, 185 186 /* OP_OBJC_MSGCALL is followed by a string in the next exp_element and then an 187 integer. The string is the selector string. The integer is the number 188 of arguments to the message call. That many plus one values are used, 189 the first one being the object pointer. This is an Objective C message */ 190 OP_OBJC_MSGCALL, 191 192 /* This is EXACTLY like OP_FUNCALL but is semantically different. 193 In F77, array subscript expressions, substring expressions 194 and function calls are all exactly the same syntactically. They may 195 only be dismabiguated at runtime. Thus this operator, which 196 indicates that we have found something of the form <name> ( <stuff> ) */ 197 OP_F77_UNDETERMINED_ARGLIST, 198 199 /* The following OP is a special one, it introduces a F77 complex 200 literal. It is followed by exactly two args that are doubles. */ 201 OP_COMPLEX, 202 203 /* OP_STRING represents a string constant. 204 Its format is the same as that of a STRUCTOP, but the string 205 data is just made into a string constant when the operation 206 is executed. */ 207 OP_STRING, 208 209 /* OP_BITSTRING represents a packed bitstring constant. 210 Its format is the same as that of a STRUCTOP, but the bitstring 211 data is just made into a bitstring constant when the operation 212 is executed. */ 213 OP_BITSTRING, 214 215 /* OP_ARRAY creates an array constant out of the following subexpressions. 216 It is followed by two exp_elements, the first containing an integer 217 that is the lower bound of the array and the second containing another 218 integer that is the upper bound of the array. The second integer is 219 followed by a repeat of OP_ARRAY, making four exp_elements total. 220 The bounds are used to compute the number of following subexpressions 221 to consume, as well as setting the bounds in the created array constant. 222 The type of the elements is taken from the type of the first subexp, 223 and they must all match. */ 224 OP_ARRAY, 225 226 /* UNOP_CAST is followed by a type pointer in the next exp_element. 227 With another UNOP_CAST at the end, this makes three exp_elements. 228 It casts the value of the following subexpression. */ 229 UNOP_CAST, 230 231 /* UNOP_MEMVAL is followed by a type pointer in the next exp_element 232 With another UNOP_MEMVAL at the end, this makes three exp_elements. 233 It casts the contents of the word addressed by the value of the 234 following subexpression. */ 235 UNOP_MEMVAL, 236 237 /* UNOP_... operate on one value from a following subexpression 238 and replace it with a result. They take no immediate arguments. */ 239 240 UNOP_NEG, /* Unary - */ 241 UNOP_LOGICAL_NOT, /* Unary ! */ 242 UNOP_COMPLEMENT, /* Unary ~ */ 243 UNOP_IND, /* Unary * */ 244 UNOP_ADDR, /* Unary & */ 245 UNOP_PREINCREMENT, /* ++ before an expression */ 246 UNOP_POSTINCREMENT, /* ++ after an expression */ 247 UNOP_PREDECREMENT, /* -- before an expression */ 248 UNOP_POSTDECREMENT, /* -- after an expression */ 249 UNOP_SIZEOF, /* Unary sizeof (followed by expression) */ 250 251 UNOP_PLUS, /* Unary plus */ 252 253 UNOP_CAP, /* Modula-2 standard (unary) procedures */ 254 UNOP_CHR, 255 UNOP_ORD, 256 UNOP_ABS, 257 UNOP_FLOAT, 258 UNOP_HIGH, 259 UNOP_MAX, 260 UNOP_MIN, 261 UNOP_ODD, 262 UNOP_TRUNC, 263 264 /* (The deleted) Chill builtin functions. */ 265 UNOP_LOWER, UNOP_UPPER, UNOP_LENGTH, UNOP_CARD, UNOP_CHMAX, UNOP_CHMIN, 266 267 OP_BOOL, /* Modula-2 builtin BOOLEAN type */ 268 OP_M2_STRING, /* Modula-2 string constants */ 269 270 /* STRUCTOP_... operate on a value from a following subexpression 271 by extracting a structure component specified by a string 272 that appears in the following exp_elements (as many as needed). 273 STRUCTOP_STRUCT is used for "." and STRUCTOP_PTR for "->". 274 They differ only in the error message given in case the value is 275 not suitable or the structure component specified is not found. 276 277 The length of the string follows the opcode, followed by 278 BYTES_TO_EXP_ELEM(length) elements containing the data of the 279 string, followed by the length again and the opcode again. */ 280 281 STRUCTOP_STRUCT, 282 STRUCTOP_PTR, 283 284 /* C++: OP_THIS is just a placeholder for the class instance variable. 285 It just comes in a tight (OP_THIS, OP_THIS) pair. */ 286 OP_THIS, 287 288 /* Objective-C: OP_OBJC_SELF is just a placeholder for the class instance 289 variable. It just comes in a tight (OP_OBJC_SELF, OP_OBJC_SELF) pair. */ 290 OP_OBJC_SELF, 291 292 /* Objective C: "@selector" pseudo-operator */ 293 OP_OBJC_SELECTOR, 294 295 /* OP_SCOPE surrounds a type name and a field name. The type 296 name is encoded as one element, but the field name stays as 297 a string, which, of course, is variable length. */ 298 OP_SCOPE, 299 300 /* Used to represent named structure field values in brace 301 initializers (or tuples as they are called in (the deleted) 302 Chill). 303 304 The gcc C syntax is NAME:VALUE or .NAME=VALUE, the (the 305 deleted) Chill syntax is .NAME:VALUE. Multiple labels (as in 306 the (the deleted) Chill syntax .NAME1,.NAME2:VALUE) is 307 represented as if it were .NAME1:(.NAME2:VALUE) (though that is 308 not valid (the deleted) Chill syntax). 309 310 The NAME is represented as for STRUCTOP_STRUCT; VALUE follows. */ 311 OP_LABELED, 312 313 /* OP_TYPE is for parsing types, and used with the "ptype" command 314 so we can look up types that are qualified by scope, either with 315 the GDB "::" operator, or the Modula-2 '.' operator. */ 316 OP_TYPE, 317 318 /* An un-looked-up identifier. */ 319 OP_NAME, 320 321 /* An unparsed expression. Used for Scheme (for now at least) */ 322 OP_EXPRSTRING, 323 324 /* An Objective C Foundation Class NSString constant */ 325 OP_OBJC_NSSTRING, 326 327 /* First extension operator. Individual language modules define 328 extra operators they need as constants with values 329 OP_LANGUAGE_SPECIFIC0 + k, for k >= 0, using a separate 330 enumerated type definition: 331 enum foo_extension_operator { 332 BINOP_MOGRIFY = OP_EXTENDED0, 333 BINOP_FROB, 334 ... 335 }; */ 336 OP_EXTENDED0, 337 338 /* Last possible extension operator. Defined to provide an 339 explicit and finite number of extended operators. */ 340 OP_EXTENDED_LAST = 0xff 341 /* NOTE: Eventually, we expect to convert to an object-oriented 342 formulation for expression operators that does away with the 343 need for these extension operators, and indeed for this 344 entire enumeration type. Therefore, consider the OP_EXTENDED 345 definitions to be a temporary measure. */ 346 }; 347 348 union exp_element 349 { 350 enum exp_opcode opcode; 351 struct symbol *symbol; 352 LONGEST longconst; 353 DOUBLEST doubleconst; 354 /* Really sizeof (union exp_element) characters (or less for the last 355 element of a string). */ 356 char string; 357 struct type *type; 358 struct internalvar *internalvar; 359 struct block *block; 360 }; 361 362 struct expression 363 { 364 const struct language_defn *language_defn; /* language it was entered in */ 365 int nelts; 366 union exp_element elts[1]; 367 }; 368 369 /* Macros for converting between number of expression elements and bytes 370 to store that many expression elements. */ 371 372 #define EXP_ELEM_TO_BYTES(elements) \ 373 ((elements) * sizeof (union exp_element)) 374 #define BYTES_TO_EXP_ELEM(bytes) \ 375 (((bytes) + sizeof (union exp_element) - 1) / sizeof (union exp_element)) 376 377 /* From parse.c */ 378 379 extern struct expression *parse_expression (char *); 380 381 extern struct expression *parse_expression_in_context (char *, int); 382 383 extern struct expression *parse_exp_1 (char **, struct block *, int); 384 385 /* The innermost context required by the stack and register variables 386 we've encountered so far. To use this, set it to NULL, then call 387 parse_<whatever>, then look at it. */ 388 extern struct block *innermost_block; 389 390 /* From eval.c */ 391 392 /* Values of NOSIDE argument to eval_subexp. */ 393 394 enum noside 395 { 396 EVAL_NORMAL, 397 EVAL_SKIP, /* Only effect is to increment pos. */ 398 EVAL_AVOID_SIDE_EFFECTS /* Don't modify any variables or 399 call any functions. The value 400 returned will have the correct 401 type, and will have an 402 approximately correct lvalue 403 type (inaccuracy: anything that is 404 listed as being in a register in 405 the function in which it was 406 declared will be lval_register). */ 407 }; 408 409 extern struct value *evaluate_subexp_standard 410 (struct type *, struct expression *, int *, enum noside); 411 412 /* From expprint.c */ 413 414 extern void print_expression (struct expression *, struct ui_file *); 415 416 extern char *op_string (enum exp_opcode); 417 418 extern void dump_raw_expression (struct expression *, struct ui_file *, char *); 419 extern void dump_prefix_expression (struct expression *, struct ui_file *); 420 421 #endif /* !defined (EXPRESSION_H) */ 422