1 /* Definitions for expressions stored in reversed prefix form, for GDB. 2 3 Copyright (C) 1986-2019 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 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 : uint8_t 43 { 44 #define OP(name) name , 45 46 #include "std-operator.def" 47 48 /* First extension operator. Individual language modules define extra 49 operators in *.def include files below with numbers higher than 50 OP_EXTENDED0. */ 51 OP (OP_EXTENDED0) 52 53 /* Language specific operators. */ 54 #include "ada-operator.def" 55 56 #undef OP 57 58 /* Existing only to swallow the last comma (',') from last .inc file. */ 59 OP_UNUSED_LAST 60 }; 61 62 union exp_element 63 { 64 enum exp_opcode opcode; 65 struct symbol *symbol; 66 struct minimal_symbol *msymbol; 67 LONGEST longconst; 68 gdb_byte floatconst[16]; 69 /* Really sizeof (union exp_element) characters (or less for the last 70 element of a string). */ 71 char string; 72 struct type *type; 73 struct internalvar *internalvar; 74 const struct block *block; 75 struct objfile *objfile; 76 }; 77 78 struct expression 79 { 80 const struct language_defn *language_defn; /* language it was 81 entered in. */ 82 struct gdbarch *gdbarch; /* architecture it was parsed in. */ 83 int nelts; 84 union exp_element elts[1]; 85 }; 86 87 typedef gdb::unique_xmalloc_ptr<expression> expression_up; 88 89 /* Macros for converting between number of expression elements and bytes 90 to store that many expression elements. */ 91 92 #define EXP_ELEM_TO_BYTES(elements) \ 93 ((elements) * sizeof (union exp_element)) 94 #define BYTES_TO_EXP_ELEM(bytes) \ 95 (((bytes) + sizeof (union exp_element) - 1) / sizeof (union exp_element)) 96 97 /* From parse.c */ 98 99 extern expression_up parse_expression (const char *); 100 101 extern expression_up parse_expression_with_language (const char *string, 102 enum language lang); 103 104 extern struct type *parse_expression_for_completion 105 (const char *, gdb::unique_xmalloc_ptr<char> *, enum type_code *); 106 107 extern expression_up parse_exp_1 (const char **, CORE_ADDR pc, 108 const struct block *, int); 109 110 /* For use by parsers; set if we want to parse an expression and 111 attempt completion. */ 112 extern int parse_completion; 113 114 /* From eval.c */ 115 116 /* Values of NOSIDE argument to eval_subexp. */ 117 118 enum noside 119 { 120 EVAL_NORMAL, 121 EVAL_SKIP, /* Only effect is to increment pos. 122 Return type information where 123 possible. */ 124 EVAL_AVOID_SIDE_EFFECTS /* Don't modify any variables or 125 call any functions. The value 126 returned will have the correct 127 type, and will have an 128 approximately correct lvalue 129 type (inaccuracy: anything that is 130 listed as being in a register in 131 the function in which it was 132 declared will be lval_register). 133 Ideally this would not even read 134 target memory, but currently it 135 does in many situations. */ 136 }; 137 138 extern struct value *evaluate_subexp_standard 139 (struct type *, struct expression *, int *, enum noside); 140 141 /* From expprint.c */ 142 143 extern void print_expression (struct expression *, struct ui_file *); 144 145 extern const char *op_name (struct expression *exp, enum exp_opcode opcode); 146 147 extern const char *op_string (enum exp_opcode); 148 149 extern void dump_raw_expression (struct expression *, 150 struct ui_file *, const char *); 151 extern void dump_prefix_expression (struct expression *, struct ui_file *); 152 153 /* In an OP_RANGE expression, either bound could be empty, indicating 154 that its value is by default that of the corresponding bound of the 155 array or string. Also, the upper end of the range can be exclusive 156 or inclusive. So we have six sorts of subrange. This enumeration 157 type is to identify this. */ 158 159 enum range_type 160 { 161 /* Neither the low nor the high bound was given -- so this refers to 162 the entire available range. */ 163 BOTH_BOUND_DEFAULT, 164 /* The low bound was not given and the high bound is inclusive. */ 165 LOW_BOUND_DEFAULT, 166 /* The high bound was not given and the low bound in inclusive. */ 167 HIGH_BOUND_DEFAULT, 168 /* Both bounds were given and both are inclusive. */ 169 NONE_BOUND_DEFAULT, 170 /* The low bound was not given and the high bound is exclusive. */ 171 NONE_BOUND_DEFAULT_EXCLUSIVE, 172 /* Both bounds were given. The low bound is inclusive and the high 173 bound is exclusive. */ 174 LOW_BOUND_DEFAULT_EXCLUSIVE, 175 }; 176 177 #endif /* !defined (EXPRESSION_H) */ 178