| 1 | /* Definitions for expressions stored in reversed prefix form, for GDB. |
| 2 | Copyright 1986, 1989, 1992, 1994 Free Software Foundation, Inc. |
| 3 | |
| 4 | This file is part of GDB. |
| 5 | |
| 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. |
| 10 | |
| 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. |
| 15 | |
| 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. */ |
| 19 | |
| 20 | #if !defined (EXPRESSION_H) |
| 21 | #define EXPRESSION_H 1 |
| 22 | |
| 23 | #ifdef __STDC__ |
| 24 | struct block; /* Forward declaration for prototypes */ |
| 25 | #endif |
| 26 | |
| 27 | /* Definitions for saved C expressions. */ |
| 28 | |
| 29 | /* An expression is represented as a vector of union exp_element's. |
| 30 | Each exp_element is an opcode, except that some opcodes cause |
| 31 | the following exp_element to be treated as a long or double constant |
| 32 | or as a variable. The opcodes are obeyed, using a stack for temporaries. |
| 33 | The value is left on the temporary stack at the end. */ |
| 34 | |
| 35 | /* When it is necessary to include a string, |
| 36 | it can occupy as many exp_elements as it needs. |
| 37 | We find the length of the string using strlen, |
| 38 | divide to find out how many exp_elements are used up, |
| 39 | and skip that many. Strings, like numbers, are indicated |
| 40 | by the preceding opcode. */ |
| 41 | |
| 42 | enum exp_opcode |
| 43 | { |
| 44 | /* Used when it's necessary to pass an opcode which will be ignored, |
| 45 | or to catch uninitialized values. */ |
| 46 | OP_NULL, |
| 47 | |
| 48 | /* BINOP_... operate on two values computed by following subexpressions, |
| 49 | replacing them by one result value. They take no immediate arguments. */ |
| 50 | |
| 51 | BINOP_ADD, /* + */ |
| 52 | BINOP_SUB, /* - */ |
| 53 | BINOP_MUL, /* * */ |
| 54 | BINOP_DIV, /* / */ |
| 55 | BINOP_REM, /* % */ |
| 56 | BINOP_MOD, /* mod (Knuth 1.2.4) */ |
| 57 | BINOP_LSH, /* << */ |
| 58 | BINOP_RSH, /* >> */ |
| 59 | BINOP_LOGICAL_AND, /* && */ |
| 60 | BINOP_LOGICAL_OR, /* || */ |
| 61 | BINOP_BITWISE_AND, /* & */ |
| 62 | BINOP_BITWISE_IOR, /* | */ |
| 63 | BINOP_BITWISE_XOR, /* ^ */ |
| 64 | BINOP_EQUAL, /* == */ |
| 65 | BINOP_NOTEQUAL, /* != */ |
| 66 | BINOP_LESS, /* < */ |
| 67 | BINOP_GTR, /* > */ |
| 68 | BINOP_LEQ, /* <= */ |
| 69 | BINOP_GEQ, /* >= */ |
| 70 | BINOP_REPEAT, /* @ */ |
| 71 | BINOP_ASSIGN, /* = */ |
| 72 | BINOP_COMMA, /* , */ |
| 73 | BINOP_SUBSCRIPT, /* x[y] */ |
| 74 | BINOP_EXP, /* Exponentiation */ |
| 75 | |
| 76 | /* C++. */ |
| 77 | |
| 78 | BINOP_MIN, /* <? */ |
| 79 | BINOP_MAX, /* >? */ |
| 80 | BINOP_SCOPE, /* :: */ |
| 81 | |
| 82 | /* STRUCTOP_MEMBER is used for pointer-to-member constructs. |
| 83 | X . * Y translates into X STRUCTOP_MEMBER Y. */ |
| 84 | STRUCTOP_MEMBER, |
| 85 | |
| 86 | /* STRUCTOP_MPTR is used for pointer-to-member constructs |
| 87 | when X is a pointer instead of an aggregate. */ |
| 88 | STRUCTOP_MPTR, |
| 89 | |
| 90 | /* end of C++. */ |
| 91 | |
| 92 | /* For Modula-2 integer division DIV */ |
| 93 | BINOP_INTDIV, |
| 94 | |
| 95 | BINOP_ASSIGN_MODIFY, /* +=, -=, *=, and so on. |
| 96 | The following exp_element is another opcode, |
| 97 | a BINOP_, saying how to modify. |
| 98 | Then comes another BINOP_ASSIGN_MODIFY, |
| 99 | making three exp_elements in total. */ |
| 100 | |
| 101 | /* Modula-2 standard (binary) procedures */ |
| 102 | BINOP_VAL, |
| 103 | BINOP_INCL, |
| 104 | BINOP_EXCL, |
| 105 | |
| 106 | /* Concatenate two operands, such as character strings or bitstrings. |
| 107 | If the first operand is a integer expression, then it means concatenate |
| 108 | the second operand with itself that many times. */ |
| 109 | BINOP_CONCAT, |
| 110 | |
| 111 | /* For Chill and Pascal. */ |
| 112 | BINOP_IN, /* Returns 1 iff ARG1 IN ARG2. */ |
| 113 | |
| 114 | /* This must be the highest BINOP_ value, for expprint.c. */ |
| 115 | BINOP_END, |
| 116 | |
| 117 | /* Operates on three values computed by following subexpressions. */ |
| 118 | TERNOP_COND, /* ?: */ |
| 119 | |
| 120 | /* A sub-string/sub-array. Chill syntax: OP1(OP2:OP3). |
| 121 | Return elements OP2 through OP3 of OP1. */ |
| 122 | TERNOP_SLICE, |
| 123 | |
| 124 | /* A sub-string/sub-array. Chill syntax: OP1(OP2 UP OP3). |
| 125 | Return OP3 elements of OP1, starting with element OP2. */ |
| 126 | TERNOP_SLICE_COUNT, |
| 127 | |
| 128 | /* Multidimensional subscript operator, such as Modula-2 x[a,b,...]. |
| 129 | The dimensionality is encoded in the operator, like the number of |
| 130 | function arguments in OP_FUNCALL, I.E. <OP><dimension><OP>. |
| 131 | The value of the first following subexpression is subscripted |
| 132 | by each of the next following subexpressions, one per dimension. */ |
| 133 | MULTI_SUBSCRIPT, |
| 134 | |
| 135 | /* The OP_... series take immediate following arguments. |
| 136 | After the arguments come another OP_... (the same one) |
| 137 | so that the grouping can be recognized from the end. */ |
| 138 | |
| 139 | /* OP_LONG is followed by a type pointer in the next exp_element |
| 140 | and the long constant value in the following exp_element. |
| 141 | Then comes another OP_LONG. |
| 142 | Thus, the operation occupies four exp_elements. */ |
| 143 | OP_LONG, |
| 144 | |
| 145 | /* OP_DOUBLE is similar but takes a double constant instead of a long. */ |
| 146 | OP_DOUBLE, |
| 147 | |
| 148 | /* OP_VAR_VALUE takes one struct block * in the following element, |
| 149 | and one struct symbol * in the following exp_element, followed by |
| 150 | another OP_VAR_VALUE, making four exp_elements. If the block is |
| 151 | non-NULL, evaluate the symbol relative to the innermost frame |
| 152 | executing in that block; if the block is NULL use the selected frame. */ |
| 153 | OP_VAR_VALUE, |
| 154 | |
| 155 | /* OP_LAST is followed by an integer in the next exp_element. |
| 156 | The integer is zero for the last value printed, |
| 157 | or it is the absolute number of a history element. |
| 158 | With another OP_LAST at the end, this makes three exp_elements. */ |
| 159 | OP_LAST, |
| 160 | |
| 161 | /* OP_REGISTER is followed by an integer in the next exp_element. |
| 162 | This is the number of a register to fetch (as an int). |
| 163 | With another OP_REGISTER at the end, this makes three exp_elements. */ |
| 164 | OP_REGISTER, |
| 165 | |
| 166 | /* OP_INTERNALVAR is followed by an internalvar ptr in the next exp_element. |
| 167 | With another OP_INTERNALVAR at the end, this makes three exp_elements. */ |
| 168 | OP_INTERNALVAR, |
| 169 | |
| 170 | /* OP_FUNCALL is followed by an integer in the next exp_element. |
| 171 | The integer is the number of args to the function call. |
| 172 | That many plus one values from following subexpressions |
| 173 | are used, the first one being the function. |
| 174 | The integer is followed by a repeat of OP_FUNCALL, |
| 175 | making three exp_elements. */ |
| 176 | OP_FUNCALL, |
| 177 | |
| 178 | /* This is EXACTLY like OP_FUNCALL but is semantically different. |
| 179 | In F77, array subscript expressions, substring expressions |
| 180 | and function calls are all exactly the same syntactically. They may |
| 181 | only be dismabiguated at runtime. Thus this operator, which |
| 182 | indicates that we have found something of the form <name> ( <stuff> ) */ |
| 183 | OP_F77_UNDETERMINED_ARGLIST, |
| 184 | |
| 185 | /* The following OP is a special one, it introduces a F77 complex |
| 186 | literal. It is followed by exactly two args that are doubles. */ |
| 187 | OP_COMPLEX, |
| 188 | |
| 189 | /* OP_STRING represents a string constant. |
| 190 | Its format is the same as that of a STRUCTOP, but the string |
| 191 | data is just made into a string constant when the operation |
| 192 | is executed. */ |
| 193 | OP_STRING, |
| 194 | |
| 195 | /* OP_BITSTRING represents a packed bitstring constant. |
| 196 | Its format is the same as that of a STRUCTOP, but the bitstring |
| 197 | data is just made into a bitstring constant when the operation |
| 198 | is executed. */ |
| 199 | OP_BITSTRING, |
| 200 | |
| 201 | /* OP_ARRAY creates an array constant out of the following subexpressions. |
| 202 | It is followed by two exp_elements, the first containing an integer |
| 203 | that is the lower bound of the array and the second containing another |
| 204 | integer that is the upper bound of the array. The second integer is |
| 205 | followed by a repeat of OP_ARRAY, making four exp_elements total. |
| 206 | The bounds are used to compute the number of following subexpressions |
| 207 | to consume, as well as setting the bounds in the created array constant. |
| 208 | The type of the elements is taken from the type of the first subexp, |
| 209 | and they must all match. */ |
| 210 | OP_ARRAY, |
| 211 | |
| 212 | /* UNOP_CAST is followed by a type pointer in the next exp_element. |
| 213 | With another UNOP_CAST at the end, this makes three exp_elements. |
| 214 | It casts the value of the following subexpression. */ |
| 215 | UNOP_CAST, |
| 216 | |
| 217 | /* UNOP_MEMVAL is followed by a type pointer in the next exp_element |
| 218 | With another UNOP_MEMVAL at the end, this makes three exp_elements. |
| 219 | It casts the contents of the word addressed by the value of the |
| 220 | following subexpression. */ |
| 221 | UNOP_MEMVAL, |
| 222 | |
| 223 | /* UNOP_... operate on one value from a following subexpression |
| 224 | and replace it with a result. They take no immediate arguments. */ |
| 225 | |
| 226 | UNOP_NEG, /* Unary - */ |
| 227 | UNOP_LOGICAL_NOT, /* Unary ! */ |
| 228 | UNOP_COMPLEMENT, /* Unary ~ */ |
| 229 | UNOP_IND, /* Unary * */ |
| 230 | UNOP_ADDR, /* Unary & */ |
| 231 | UNOP_PREINCREMENT, /* ++ before an expression */ |
| 232 | UNOP_POSTINCREMENT, /* ++ after an expression */ |
| 233 | UNOP_PREDECREMENT, /* -- before an expression */ |
| 234 | UNOP_POSTDECREMENT, /* -- after an expression */ |
| 235 | UNOP_SIZEOF, /* Unary sizeof (followed by expression) */ |
| 236 | |
| 237 | UNOP_PLUS, /* Unary plus */ |
| 238 | |
| 239 | UNOP_CAP, /* Modula-2 standard (unary) procedures */ |
| 240 | UNOP_CHR, |
| 241 | UNOP_ORD, |
| 242 | UNOP_ABS, |
| 243 | UNOP_FLOAT, |
| 244 | UNOP_HIGH, |
| 245 | UNOP_MAX, |
| 246 | UNOP_MIN, |
| 247 | UNOP_ODD, |
| 248 | UNOP_TRUNC, |
| 249 | |
| 250 | OP_BOOL, /* Modula-2 builtin BOOLEAN type */ |
| 251 | OP_M2_STRING, /* Modula-2 string constants */ |
| 252 | |
| 253 | /* STRUCTOP_... operate on a value from a following subexpression |
| 254 | by extracting a structure component specified by a string |
| 255 | that appears in the following exp_elements (as many as needed). |
| 256 | STRUCTOP_STRUCT is used for "." and STRUCTOP_PTR for "->". |
| 257 | They differ only in the error message given in case the value is |
| 258 | not suitable or the structure component specified is not found. |
| 259 | |
| 260 | The length of the string follows the opcode, followed by |
| 261 | BYTES_TO_EXP_ELEM(length) elements containing the data of the |
| 262 | string, followed by the length again and the opcode again. */ |
| 263 | |
| 264 | STRUCTOP_STRUCT, |
| 265 | STRUCTOP_PTR, |
| 266 | |
| 267 | /* C++ */ |
| 268 | /* OP_THIS is just a placeholder for the class instance variable. |
| 269 | It just comes in a tight (OP_THIS, OP_THIS) pair. */ |
| 270 | OP_THIS, |
| 271 | |
| 272 | /* OP_SCOPE surrounds a type name and a field name. The type |
| 273 | name is encoded as one element, but the field name stays as |
| 274 | a string, which, of course, is variable length. */ |
| 275 | OP_SCOPE, |
| 276 | |
| 277 | /* Used to represent named structure field values in brace initializers |
| 278 | (or tuples as they are called in Chill). |
| 279 | The gcc C syntax is NAME:VALUE or .NAME=VALUE, the Chill syntax is |
| 280 | .NAME:VALUE. Multiple labels (as in the Chill syntax |
| 281 | .NAME1,.NAME2:VALUE) is represented as if it were |
| 282 | .NAME1:(.NAME2:VALUE) (though that is not valid Chill syntax). |
| 283 | |
| 284 | The NAME is represented as for STRUCTOP_STRUCT; VALUE follows. */ |
| 285 | OP_LABELED, |
| 286 | |
| 287 | /* OP_TYPE is for parsing types, and used with the "ptype" command |
| 288 | so we can look up types that are qualified by scope, either with |
| 289 | the GDB "::" operator, or the Modula-2 '.' operator. */ |
| 290 | OP_TYPE |
| 291 | }; |
| 292 | |
| 293 | union exp_element |
| 294 | { |
| 295 | enum exp_opcode opcode; |
| 296 | struct symbol *symbol; |
| 297 | LONGEST longconst; |
| 298 | double doubleconst; |
| 299 | /* Really sizeof (union exp_element) characters (or less for the last |
| 300 | element of a string). */ |
| 301 | char string; |
| 302 | struct type *type; |
| 303 | struct internalvar *internalvar; |
| 304 | struct block *block; |
| 305 | }; |
| 306 | |
| 307 | struct expression |
| 308 | { |
| 309 | const struct language_defn *language_defn; /* language it was entered in */ |
| 310 | int nelts; |
| 311 | union exp_element elts[1]; |
| 312 | }; |
| 313 | |
| 314 | /* Macros for converting between number of expression elements and bytes |
| 315 | to store that many expression elements. */ |
| 316 | |
| 317 | #define EXP_ELEM_TO_BYTES(elements) \ |
| 318 | ((elements) * sizeof (union exp_element)) |
| 319 | #define BYTES_TO_EXP_ELEM(bytes) \ |
| 320 | (((bytes) + sizeof (union exp_element) - 1) / sizeof (union exp_element)) |
| 321 | |
| 322 | #include "value.h" |
| 323 | |
| 324 | /* From parse.c */ |
| 325 | |
| 326 | extern struct expression *parse_expression PARAMS ((char *)); |
| 327 | |
| 328 | extern struct expression *parse_exp_1 PARAMS ((char **, struct block *, int)); |
| 329 | |
| 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; |
| 334 | |
| 335 | /* From eval.c */ |
| 336 | |
| 337 | /* Values of NOSIDE argument to eval_subexp. */ |
| 338 | |
| 339 | enum noside |
| 340 | { |
| 341 | EVAL_NORMAL, |
| 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). */ |
| 352 | }; |
| 353 | |
| 354 | extern struct value* evaluate_subexp_standard |
| 355 | PARAMS ((struct type *, struct expression *, int*, enum noside)); |
| 356 | |
| 357 | extern value_ptr evaluate_subexp_with_coercion PARAMS ((struct expression *, |
| 358 | int *, enum noside)); |
| 359 | |
| 360 | /* From expprint.c */ |
| 361 | |
| 362 | extern void print_expression PARAMS ((struct expression *, GDB_FILE *)); |
| 363 | |
| 364 | extern char *op_string PARAMS ((enum exp_opcode)); |
| 365 | |
| 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. */ |
| 370 | |
| 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)) |
| 374 | #else |
| 375 | #define DUMP_EXPRESSION(exp,file,note) /* Null expansion */ |
| 376 | #endif /* DEBUG_EXPRESSIONS */ |
| 377 | |
| 378 | #endif /* !defined (EXPRESSION_H) */ |