1 /* Definitions for expressions stored in reversed prefix form, for GDB. 2 3 Copyright (C) 1986-2017 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 typedef gdb::unique_xmalloc_ptr<expression> expression_up; 89 90 /* Macros for converting between number of expression elements and bytes 91 to store that many expression elements. */ 92 93 #define EXP_ELEM_TO_BYTES(elements) \ 94 ((elements) * sizeof (union exp_element)) 95 #define BYTES_TO_EXP_ELEM(bytes) \ 96 (((bytes) + sizeof (union exp_element) - 1) / sizeof (union exp_element)) 97 98 /* From parse.c */ 99 100 extern expression_up parse_expression (const char *); 101 102 extern expression_up parse_expression_with_language (const char *string, 103 enum language lang); 104 105 extern struct type *parse_expression_for_completion (const char *, char **, 106 enum type_code *); 107 108 extern expression_up parse_exp_1 (const char **, CORE_ADDR pc, 109 const struct block *, int); 110 111 /* For use by parsers; set if we want to parse an expression and 112 attempt completion. */ 113 extern int parse_completion; 114 115 /* The innermost context required by the stack and register variables 116 we've encountered so far. To use this, set it to NULL, then call 117 parse_<whatever>, then look at it. */ 118 extern const struct block *innermost_block; 119 120 /* From eval.c */ 121 122 /* Values of NOSIDE argument to eval_subexp. */ 123 124 enum noside 125 { 126 EVAL_NORMAL, 127 EVAL_SKIP, /* Only effect is to increment pos. */ 128 EVAL_AVOID_SIDE_EFFECTS /* Don't modify any variables or 129 call any functions. The value 130 returned will have the correct 131 type, and will have an 132 approximately correct lvalue 133 type (inaccuracy: anything that is 134 listed as being in a register in 135 the function in which it was 136 declared will be lval_register). 137 Ideally this would not even read 138 target memory, but currently it 139 does in many situations. */ 140 }; 141 142 extern struct value *evaluate_subexp_standard 143 (struct type *, struct expression *, int *, enum noside); 144 145 /* From expprint.c */ 146 147 extern void print_expression (struct expression *, struct ui_file *); 148 149 extern const char *op_name (struct expression *exp, enum exp_opcode opcode); 150 151 extern const char *op_string (enum exp_opcode); 152 153 extern void dump_raw_expression (struct expression *, 154 struct ui_file *, const char *); 155 extern void dump_prefix_expression (struct expression *, struct ui_file *); 156 157 /* In an OP_RANGE expression, either bound could be empty, indicating 158 that its value is by default that of the corresponding bound of the 159 array or string. So we have four sorts of subrange. This 160 enumeration type is to identify this. */ 161 162 enum range_type 163 { 164 BOTH_BOUND_DEFAULT, /* "(:)" */ 165 LOW_BOUND_DEFAULT, /* "(:high)" */ 166 HIGH_BOUND_DEFAULT, /* "(low:)" */ 167 NONE_BOUND_DEFAULT /* "(low:high)" */ 168 }; 169 170 #endif /* !defined (EXPRESSION_H) */ 171