1 /* Definitions for expressions stored in reversed prefix form, for GDB. 2 3 Copyright (C) 1986-2016 Free Software Foundation, Inc. 4 5 This file is part of GDB. 6 7 This program is free software; you can redistribute it and/or modify 8 it under the terms of the GNU General Public License as published by 9 the Free Software Foundation; either version 3 of the License, or 10 (at your option) any later version. 11 12 This program is distributed in the hope that it will be useful, 13 but WITHOUT ANY WARRANTY; without even the implied warranty of 14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 GNU General Public License for more details. 16 17 You should have received a copy of the GNU General Public License 18 along with this program. If not, see <http://www.gnu.org/licenses/>. */ 19 20 #if !defined (EXPRESSION_H) 21 #define EXPRESSION_H 1 22 23 24 #include "symtab.h" /* Needed for "struct block" type. */ 25 #include "doublest.h" /* Needed for DOUBLEST. */ 26 27 28 /* Definitions for saved C expressions. */ 29 30 /* An expression is represented as a vector of union exp_element's. 31 Each exp_element is an opcode, except that some opcodes cause 32 the following exp_element to be treated as a long or double constant 33 or as a variable. The opcodes are obeyed, using a stack for temporaries. 34 The value is left on the temporary stack at the end. */ 35 36 /* When it is necessary to include a string, 37 it can occupy as many exp_elements as it needs. 38 We find the length of the string using strlen, 39 divide to find out how many exp_elements are used up, 40 and skip that many. Strings, like numbers, are indicated 41 by the preceding opcode. */ 42 43 enum exp_opcode 44 { 45 #define OP(name) name , 46 47 #include "std-operator.def" 48 49 /* First extension operator. Individual language modules define extra 50 operators in *.def include files below with numbers higher than 51 OP_EXTENDED0. */ 52 OP (OP_EXTENDED0) 53 54 /* Language specific operators. */ 55 #include "ada-operator.def" 56 57 #undef OP 58 59 /* Existing only to swallow the last comma (',') from last .inc file. */ 60 OP_UNUSED_LAST 61 }; 62 63 union exp_element 64 { 65 enum exp_opcode opcode; 66 struct symbol *symbol; 67 LONGEST longconst; 68 DOUBLEST doubleconst; 69 gdb_byte decfloatconst[16]; 70 /* Really sizeof (union exp_element) characters (or less for the last 71 element of a string). */ 72 char string; 73 struct type *type; 74 struct internalvar *internalvar; 75 const struct block *block; 76 struct objfile *objfile; 77 }; 78 79 struct expression 80 { 81 const struct language_defn *language_defn; /* language it was 82 entered in. */ 83 struct gdbarch *gdbarch; /* architecture it was parsed in. */ 84 int nelts; 85 union exp_element elts[1]; 86 }; 87 88 /* Macros for converting between number of expression elements and bytes 89 to store that many expression elements. */ 90 91 #define EXP_ELEM_TO_BYTES(elements) \ 92 ((elements) * sizeof (union exp_element)) 93 #define BYTES_TO_EXP_ELEM(bytes) \ 94 (((bytes) + sizeof (union exp_element) - 1) / sizeof (union exp_element)) 95 96 /* From parse.c */ 97 98 extern struct expression *parse_expression (const char *); 99 100 extern struct expression *parse_expression_with_language (const char *string, 101 enum language lang); 102 103 extern struct type *parse_expression_for_completion (const char *, char **, 104 enum type_code *); 105 106 extern struct expression *parse_exp_1 (const char **, CORE_ADDR pc, 107 const struct block *, int); 108 109 /* For use by parsers; set if we want to parse an expression and 110 attempt completion. */ 111 extern int parse_completion; 112 113 /* The innermost context required by the stack and register variables 114 we've encountered so far. To use this, set it to NULL, then call 115 parse_<whatever>, then look at it. */ 116 extern const struct block *innermost_block; 117 118 /* From eval.c */ 119 120 /* Values of NOSIDE argument to eval_subexp. */ 121 122 enum noside 123 { 124 EVAL_NORMAL, 125 EVAL_SKIP, /* Only effect is to increment pos. */ 126 EVAL_AVOID_SIDE_EFFECTS /* Don't modify any variables or 127 call any functions. The value 128 returned will have the correct 129 type, and will have an 130 approximately correct lvalue 131 type (inaccuracy: anything that is 132 listed as being in a register in 133 the function in which it was 134 declared will be lval_register). 135 Ideally this would not even read 136 target memory, but currently it 137 does in many situations. */ 138 }; 139 140 extern struct value *evaluate_subexp_standard 141 (struct type *, struct expression *, int *, enum noside); 142 143 /* From expprint.c */ 144 145 extern void print_expression (struct expression *, struct ui_file *); 146 147 extern char *op_name (struct expression *exp, enum exp_opcode opcode); 148 149 extern char *op_string (enum exp_opcode); 150 151 extern void dump_raw_expression (struct expression *, 152 struct ui_file *, char *); 153 extern void dump_prefix_expression (struct expression *, struct ui_file *); 154 155 /* In an OP_RANGE expression, either bound could be empty, indicating 156 that its value is by default that of the corresponding bound of the 157 array or string. So we have four sorts of subrange. This 158 enumeration type is to identify this. */ 159 160 enum range_type 161 { 162 BOTH_BOUND_DEFAULT, /* "(:)" */ 163 LOW_BOUND_DEFAULT, /* "(:high)" */ 164 HIGH_BOUND_DEFAULT, /* "(low:)" */ 165 NONE_BOUND_DEFAULT /* "(low:high)" */ 166 }; 167 168 #endif /* !defined (EXPRESSION_H) */ 169