1 /* Definitions for expressions stored in reversed prefix form, for GDB. 2 3 Copyright (C) 1986, 1989, 1992, 1994, 2000, 2003, 2005, 2007, 2008, 2009, 4 2010 Free Software 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 3 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, see <http://www.gnu.org/licenses/>. */ 20 21 #if !defined (EXPRESSION_H) 22 #define EXPRESSION_H 1 23 24 25 #include "symtab.h" /* Needed for "struct block" type. */ 26 #include "doublest.h" /* Needed for DOUBLEST. */ 27 28 29 /* Definitions for saved C expressions. */ 30 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. */ 36 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. */ 43 44 enum exp_opcode 45 { 46 /* Used when it's necessary to pass an opcode which will be ignored, 47 or to catch uninitialized values. */ 48 OP_NULL, 49 50 /* BINOP_... operate on two values computed by following subexpressions, 51 replacing them by one result value. They take no immediate arguments. */ 52 53 BINOP_ADD, /* + */ 54 BINOP_SUB, /* - */ 55 BINOP_MUL, /* * */ 56 BINOP_DIV, /* / */ 57 BINOP_REM, /* % */ 58 BINOP_MOD, /* mod (Knuth 1.2.4) */ 59 BINOP_LSH, /* << */ 60 BINOP_RSH, /* >> */ 61 BINOP_LOGICAL_AND, /* && */ 62 BINOP_LOGICAL_OR, /* || */ 63 BINOP_BITWISE_AND, /* & */ 64 BINOP_BITWISE_IOR, /* | */ 65 BINOP_BITWISE_XOR, /* ^ */ 66 BINOP_EQUAL, /* == */ 67 BINOP_NOTEQUAL, /* != */ 68 BINOP_LESS, /* < */ 69 BINOP_GTR, /* > */ 70 BINOP_LEQ, /* <= */ 71 BINOP_GEQ, /* >= */ 72 BINOP_REPEAT, /* @ */ 73 BINOP_ASSIGN, /* = */ 74 BINOP_COMMA, /* , */ 75 BINOP_SUBSCRIPT, /* x[y] */ 76 BINOP_EXP, /* Exponentiation */ 77 78 /* C++. */ 79 80 BINOP_MIN, /* <? */ 81 BINOP_MAX, /* >? */ 82 83 /* STRUCTOP_MEMBER is used for pointer-to-member constructs. 84 X . * Y translates into X STRUCTOP_MEMBER Y. */ 85 STRUCTOP_MEMBER, 86 87 /* STRUCTOP_MPTR is used for pointer-to-member constructs 88 when X is a pointer instead of an aggregate. */ 89 STRUCTOP_MPTR, 90 91 /* TYPE_INSTANCE is used when the user specifies a specific 92 type instantiation for overloaded methods/functions. 93 94 The format is: 95 TYPE_INSTANCE num_types type0 ... typeN num_types TYPE_INSTANCE */ 96 TYPE_INSTANCE, 97 98 /* end of C++. */ 99 100 /* For Modula-2 integer division DIV */ 101 BINOP_INTDIV, 102 103 BINOP_ASSIGN_MODIFY, /* +=, -=, *=, and so on. 104 The following exp_element is another opcode, 105 a BINOP_, saying how to modify. 106 Then comes another BINOP_ASSIGN_MODIFY, 107 making three exp_elements in total. */ 108 109 /* Modula-2 standard (binary) procedures */ 110 BINOP_VAL, 111 112 /* Concatenate two operands, such as character strings or bitstrings. 113 If the first operand is a integer expression, then it means concatenate 114 the second operand with itself that many times. */ 115 BINOP_CONCAT, 116 117 /* For (the deleted) Chill and Pascal. */ 118 BINOP_IN, /* Returns 1 iff ARG1 IN ARG2. */ 119 120 /* This is the "colon operator" used various places in (the 121 deleted) Chill. */ 122 BINOP_RANGE, 123 124 /* This must be the highest BINOP_ value, for expprint.c. */ 125 BINOP_END, 126 127 /* Operates on three values computed by following subexpressions. */ 128 TERNOP_COND, /* ?: */ 129 130 /* A sub-string/sub-array. (the deleted) Chill syntax: 131 OP1(OP2:OP3). Return elements OP2 through OP3 of OP1. */ 132 TERNOP_SLICE, 133 134 /* A sub-string/sub-array. (The deleted) Chill syntax: OP1(OP2 UP 135 OP3). Return OP3 elements of OP1, starting with element 136 OP2. */ 137 TERNOP_SLICE_COUNT, 138 139 /* Multidimensional subscript operator, such as Modula-2 x[a,b,...]. 140 The dimensionality is encoded in the operator, like the number of 141 function arguments in OP_FUNCALL, I.E. <OP><dimension><OP>. 142 The value of the first following subexpression is subscripted 143 by each of the next following subexpressions, one per dimension. */ 144 MULTI_SUBSCRIPT, 145 146 /* The OP_... series take immediate following arguments. 147 After the arguments come another OP_... (the same one) 148 so that the grouping can be recognized from the end. */ 149 150 /* OP_LONG is followed by a type pointer in the next exp_element 151 and the long constant value in the following exp_element. 152 Then comes another OP_LONG. 153 Thus, the operation occupies four exp_elements. */ 154 OP_LONG, 155 156 /* OP_DOUBLE is similar but takes a DOUBLEST constant instead of a long. */ 157 OP_DOUBLE, 158 159 /* OP_VAR_VALUE takes one struct block * in the following element, 160 and one struct symbol * in the following exp_element, followed by 161 another OP_VAR_VALUE, making four exp_elements. If the block is 162 non-NULL, evaluate the symbol relative to the innermost frame 163 executing in that block; if the block is NULL use the selected frame. */ 164 OP_VAR_VALUE, 165 166 /* OP_LAST is followed by an integer in the next exp_element. 167 The integer is zero for the last value printed, 168 or it is the absolute number of a history element. 169 With another OP_LAST at the end, this makes three exp_elements. */ 170 OP_LAST, 171 172 /* OP_REGISTER is followed by a string in the next exp_element. 173 This is the name of a register to fetch. */ 174 OP_REGISTER, 175 176 /* OP_INTERNALVAR is followed by an internalvar ptr in the next exp_element. 177 With another OP_INTERNALVAR at the end, this makes three exp_elements. */ 178 OP_INTERNALVAR, 179 180 /* OP_FUNCALL is followed by an integer in the next exp_element. 181 The integer is the number of args to the function call. 182 That many plus one values from following subexpressions 183 are used, the first one being the function. 184 The integer is followed by a repeat of OP_FUNCALL, 185 making three exp_elements. */ 186 OP_FUNCALL, 187 188 /* OP_OBJC_MSGCALL is followed by a string in the next exp_element and then an 189 integer. The string is the selector string. The integer is the number 190 of arguments to the message call. That many plus one values are used, 191 the first one being the object pointer. This is an Objective C message */ 192 OP_OBJC_MSGCALL, 193 194 /* This is EXACTLY like OP_FUNCALL but is semantically different. 195 In F77, array subscript expressions, substring expressions 196 and function calls are all exactly the same syntactically. They may 197 only be disambiguated at runtime. Thus this operator, which 198 indicates that we have found something of the form <name> ( <stuff> ) */ 199 OP_F77_UNDETERMINED_ARGLIST, 200 201 /* OP_COMPLEX takes a type in the following element, followed by another 202 OP_COMPLEX, making three exp_elements. It is followed by two double 203 args, and converts them into a complex number of the given type. */ 204 OP_COMPLEX, 205 206 /* OP_STRING represents a string constant. 207 Its format is the same as that of a STRUCTOP, but the string 208 data is just made into a string constant when the operation 209 is executed. */ 210 OP_STRING, 211 212 /* OP_BITSTRING represents a packed bitstring constant. 213 Its format is the same as that of a STRUCTOP, but the bitstring 214 data is just made into a bitstring constant when the operation 215 is executed. */ 216 OP_BITSTRING, 217 218 /* OP_ARRAY creates an array constant out of the following subexpressions. 219 It is followed by two exp_elements, the first containing an integer 220 that is the lower bound of the array and the second containing another 221 integer that is the upper bound of the array. The second integer is 222 followed by a repeat of OP_ARRAY, making four exp_elements total. 223 The bounds are used to compute the number of following subexpressions 224 to consume, as well as setting the bounds in the created array constant. 225 The type of the elements is taken from the type of the first subexp, 226 and they must all match. */ 227 OP_ARRAY, 228 229 /* UNOP_CAST is followed by a type pointer in the next exp_element. 230 With another UNOP_CAST at the end, this makes three exp_elements. 231 It casts the value of the following subexpression. */ 232 UNOP_CAST, 233 234 /* The C++ dynamic_cast operator. */ 235 UNOP_DYNAMIC_CAST, 236 237 /* The C++ reinterpret_cast operator. */ 238 UNOP_REINTERPRET_CAST, 239 240 /* UNOP_MEMVAL is followed by a type pointer in the next exp_element 241 With another UNOP_MEMVAL at the end, this makes three exp_elements. 242 It casts the contents of the word addressed by the value of the 243 following subexpression. */ 244 UNOP_MEMVAL, 245 246 /* UNOP_MEMVAL_TLS is followed by a `struct objfile' pointer in the next 247 exp_element and a type pointer in the following exp_element. 248 With another UNOP_MEMVAL_TLS at the end, this makes four exp_elements. 249 It casts the contents of the word offsetted by the value of the 250 following subexpression from the TLS specified by `struct objfile'. */ 251 UNOP_MEMVAL_TLS, 252 253 /* UNOP_... operate on one value from a following subexpression 254 and replace it with a result. They take no immediate arguments. */ 255 256 UNOP_NEG, /* Unary - */ 257 UNOP_LOGICAL_NOT, /* Unary ! */ 258 UNOP_COMPLEMENT, /* Unary ~ */ 259 UNOP_IND, /* Unary * */ 260 UNOP_ADDR, /* Unary & */ 261 UNOP_PREINCREMENT, /* ++ before an expression */ 262 UNOP_POSTINCREMENT, /* ++ after an expression */ 263 UNOP_PREDECREMENT, /* -- before an expression */ 264 UNOP_POSTDECREMENT, /* -- after an expression */ 265 UNOP_SIZEOF, /* Unary sizeof (followed by expression) */ 266 267 UNOP_PLUS, /* Unary plus */ 268 269 UNOP_CAP, /* Modula-2 standard (unary) procedures */ 270 UNOP_CHR, 271 UNOP_ORD, 272 UNOP_ABS, 273 UNOP_FLOAT, 274 UNOP_HIGH, 275 UNOP_MAX, 276 UNOP_MIN, 277 UNOP_ODD, 278 UNOP_TRUNC, 279 280 OP_BOOL, /* Modula-2 builtin BOOLEAN type */ 281 OP_M2_STRING, /* Modula-2 string constants */ 282 283 /* STRUCTOP_... operate on a value from a following subexpression 284 by extracting a structure component specified by a string 285 that appears in the following exp_elements (as many as needed). 286 STRUCTOP_STRUCT is used for "." and STRUCTOP_PTR for "->". 287 They differ only in the error message given in case the value is 288 not suitable or the structure component specified is not found. 289 290 The length of the string follows the opcode, followed by 291 BYTES_TO_EXP_ELEM(length) elements containing the data of the 292 string, followed by the length again and the opcode again. */ 293 294 STRUCTOP_STRUCT, 295 STRUCTOP_PTR, 296 297 /* C++: OP_THIS is just a placeholder for the class instance variable. 298 It just comes in a tight (OP_THIS, OP_THIS) pair. */ 299 OP_THIS, 300 301 /* Objective-C: OP_OBJC_SELF is just a placeholder for the class instance 302 variable. It just comes in a tight (OP_OBJC_SELF, OP_OBJC_SELF) pair. */ 303 OP_OBJC_SELF, 304 305 /* Objective C: "@selector" pseudo-operator */ 306 OP_OBJC_SELECTOR, 307 308 /* OP_SCOPE surrounds a type name and a field name. The type 309 name is encoded as one element, but the field name stays as 310 a string, which, of course, is variable length. */ 311 OP_SCOPE, 312 313 /* Used to represent named structure field values in brace 314 initializers (or tuples as they are called in (the deleted) 315 Chill). 316 317 The gcc C syntax is NAME:VALUE or .NAME=VALUE, the (the 318 deleted) Chill syntax is .NAME:VALUE. Multiple labels (as in 319 the (the deleted) Chill syntax .NAME1,.NAME2:VALUE) is 320 represented as if it were .NAME1:(.NAME2:VALUE) (though that is 321 not valid (the deleted) Chill syntax). 322 323 The NAME is represented as for STRUCTOP_STRUCT; VALUE follows. */ 324 OP_LABELED, 325 326 /* OP_TYPE is for parsing types, and used with the "ptype" command 327 so we can look up types that are qualified by scope, either with 328 the GDB "::" operator, or the Modula-2 '.' operator. */ 329 OP_TYPE, 330 331 /* An un-looked-up identifier. */ 332 OP_NAME, 333 334 /* An Objective C Foundation Class NSString constant */ 335 OP_OBJC_NSSTRING, 336 337 /* A F90 array range operator (for "exp:exp", "exp:", ":exp" and ":"). */ 338 OP_F90_RANGE, 339 340 /* OP_DECFLOAT is followed by a type pointer in the next exp_element 341 and a dec long constant value in the following exp_element. 342 Then comes another OP_DECFLOAT. */ 343 OP_DECFLOAT, 344 345 /* OP_ADL_FUNC specifies that the function is to be looked up in an 346 Argument Dependent manner (Koenig lookup). */ 347 OP_ADL_FUNC, 348 349 /* First extension operator. Individual language modules define 350 extra operators in *.inc include files below always starting with 351 numbering at OP_EXTENDED0: 352 BINOP_MOGRIFY = OP_EXTENDED0, 353 BINOP_FROB, 354 ... */ 355 OP_EXTENDED0, 356 357 /* Last possible extension operator. Defined to provide an 358 explicit and finite number of extended operators. */ 359 OP_EXTENDED_LAST = 0xff, 360 /* NOTE: Eventually, we expect to convert to an object-oriented 361 formulation for expression operators that does away with the 362 need for these extension operators, and indeed for this 363 entire enumeration type. Therefore, consider the OP_EXTENDED 364 definitions to be a temporary measure. */ 365 366 /* Each language specific set of operators starts at OP_EXTENDED0. */ 367 #include "ada-operator.inc" 368 369 /* Existing only to swallow the last comma (',') from last .inc file. */ 370 OP_UNUSED_LAST 371 }; 372 373 union exp_element 374 { 375 enum exp_opcode opcode; 376 struct symbol *symbol; 377 LONGEST longconst; 378 DOUBLEST doubleconst; 379 gdb_byte decfloatconst[16]; 380 /* Really sizeof (union exp_element) characters (or less for the last 381 element of a string). */ 382 char string; 383 struct type *type; 384 struct internalvar *internalvar; 385 struct block *block; 386 struct objfile *objfile; 387 }; 388 389 struct expression 390 { 391 const struct language_defn *language_defn; /* language it was entered in */ 392 struct gdbarch *gdbarch; /* architecture it was parsed in */ 393 int nelts; 394 union exp_element elts[1]; 395 }; 396 397 /* Macros for converting between number of expression elements and bytes 398 to store that many expression elements. */ 399 400 #define EXP_ELEM_TO_BYTES(elements) \ 401 ((elements) * sizeof (union exp_element)) 402 #define BYTES_TO_EXP_ELEM(bytes) \ 403 (((bytes) + sizeof (union exp_element) - 1) / sizeof (union exp_element)) 404 405 /* From parse.c */ 406 407 extern struct expression *parse_expression (char *); 408 409 extern struct type *parse_field_expression (char *, char **); 410 411 extern struct expression *parse_exp_1 (char **, struct block *, int); 412 413 /* For use by parsers; set if we want to parse an expression and 414 attempt to complete a field name. */ 415 extern int in_parse_field; 416 417 /* The innermost context required by the stack and register variables 418 we've encountered so far. To use this, set it to NULL, then call 419 parse_<whatever>, then look at it. */ 420 extern struct block *innermost_block; 421 422 /* From eval.c */ 423 424 /* Values of NOSIDE argument to eval_subexp. */ 425 426 enum noside 427 { 428 EVAL_NORMAL, 429 EVAL_SKIP, /* Only effect is to increment pos. */ 430 EVAL_AVOID_SIDE_EFFECTS /* Don't modify any variables or 431 call any functions. The value 432 returned will have the correct 433 type, and will have an 434 approximately correct lvalue 435 type (inaccuracy: anything that is 436 listed as being in a register in 437 the function in which it was 438 declared will be lval_register). */ 439 }; 440 441 extern struct value *evaluate_subexp_standard 442 (struct type *, struct expression *, int *, enum noside); 443 444 /* From expprint.c */ 445 446 extern void print_expression (struct expression *, struct ui_file *); 447 448 extern char *op_string (enum exp_opcode); 449 450 extern void dump_raw_expression (struct expression *, struct ui_file *, char *); 451 extern void dump_prefix_expression (struct expression *, struct ui_file *); 452 453 #endif /* !defined (EXPRESSION_H) */ 454