| 1 | /* Definitions for expressions stored in reversed prefix form, for GDB. |
| 2 | |
| 3 | Copyright (C) 1986-2021 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 | #include "gdbtypes.h" |
| 24 | |
| 25 | /* While parsing expressions we need to track the innermost lexical block |
| 26 | that we encounter. In some situations we need to track the innermost |
| 27 | block just for symbols, and in other situations we want to track the |
| 28 | innermost block for symbols and registers. These flags are used by the |
| 29 | innermost block tracker to control which blocks we consider for the |
| 30 | innermost block. These flags can be combined together as needed. */ |
| 31 | |
| 32 | enum innermost_block_tracker_type |
| 33 | { |
| 34 | /* Track the innermost block for symbols within an expression. */ |
| 35 | INNERMOST_BLOCK_FOR_SYMBOLS = (1 << 0), |
| 36 | |
| 37 | /* Track the innermost block for registers within an expression. */ |
| 38 | INNERMOST_BLOCK_FOR_REGISTERS = (1 << 1) |
| 39 | }; |
| 40 | DEF_ENUM_FLAGS_TYPE (enum innermost_block_tracker_type, |
| 41 | innermost_block_tracker_types); |
| 42 | |
| 43 | enum exp_opcode : uint8_t |
| 44 | { |
| 45 | #define OP(name) name , |
| 46 | |
| 47 | #include "std-operator.def" |
| 48 | |
| 49 | #undef OP |
| 50 | }; |
| 51 | |
| 52 | /* Values of NOSIDE argument to eval_subexp. */ |
| 53 | |
| 54 | enum noside |
| 55 | { |
| 56 | EVAL_NORMAL, |
| 57 | EVAL_AVOID_SIDE_EFFECTS /* Don't modify any variables or |
| 58 | call any functions. The value |
| 59 | returned will have the correct |
| 60 | type, and will have an |
| 61 | approximately correct lvalue |
| 62 | type (inaccuracy: anything that is |
| 63 | listed as being in a register in |
| 64 | the function in which it was |
| 65 | declared will be lval_register). |
| 66 | Ideally this would not even read |
| 67 | target memory, but currently it |
| 68 | does in many situations. */ |
| 69 | }; |
| 70 | |
| 71 | struct expression; |
| 72 | struct agent_expr; |
| 73 | struct axs_value; |
| 74 | struct type; |
| 75 | struct ui_file; |
| 76 | |
| 77 | namespace expr |
| 78 | { |
| 79 | |
| 80 | class operation; |
| 81 | typedef std::unique_ptr<operation> operation_up; |
| 82 | |
| 83 | /* Base class for an operation. An operation is a single component of |
| 84 | an expression. */ |
| 85 | |
| 86 | class operation |
| 87 | { |
| 88 | protected: |
| 89 | |
| 90 | operation () = default; |
| 91 | DISABLE_COPY_AND_ASSIGN (operation); |
| 92 | |
| 93 | public: |
| 94 | |
| 95 | virtual ~operation () = default; |
| 96 | |
| 97 | /* Evaluate this operation. */ |
| 98 | virtual value *evaluate (struct type *expect_type, |
| 99 | struct expression *exp, |
| 100 | enum noside noside) = 0; |
| 101 | |
| 102 | /* Evaluate this operation in a context where C-like coercion is |
| 103 | needed. */ |
| 104 | virtual value *evaluate_with_coercion (struct expression *exp, |
| 105 | enum noside noside) |
| 106 | { |
| 107 | return evaluate (nullptr, exp, noside); |
| 108 | } |
| 109 | |
| 110 | /* Evaluate this expression in the context of a cast to |
| 111 | EXPECT_TYPE. */ |
| 112 | virtual value *evaluate_for_cast (struct type *expect_type, |
| 113 | struct expression *exp, |
| 114 | enum noside noside); |
| 115 | |
| 116 | /* Evaluate this expression in the context of a sizeof |
| 117 | operation. */ |
| 118 | virtual value *evaluate_for_sizeof (struct expression *exp, |
| 119 | enum noside noside); |
| 120 | |
| 121 | /* Evaluate this expression in the context of an address-of |
| 122 | operation. Must return the address. */ |
| 123 | virtual value *evaluate_for_address (struct expression *exp, |
| 124 | enum noside noside); |
| 125 | |
| 126 | /* Evaluate a function call, with this object as the callee. |
| 127 | EXPECT_TYPE, EXP, and NOSIDE have the same meaning as in |
| 128 | 'evaluate'. ARGS holds the operations that should be evaluated |
| 129 | to get the arguments to the call. */ |
| 130 | virtual value *evaluate_funcall (struct type *expect_type, |
| 131 | struct expression *exp, |
| 132 | enum noside noside, |
| 133 | const std::vector<operation_up> &args) |
| 134 | { |
| 135 | /* Defer to the helper overload. */ |
| 136 | return evaluate_funcall (expect_type, exp, noside, nullptr, args); |
| 137 | } |
| 138 | |
| 139 | /* True if this is a constant expression. */ |
| 140 | virtual bool constant_p () const |
| 141 | { return false; } |
| 142 | |
| 143 | /* Return true if this operation uses OBJFILE (and will become |
| 144 | dangling when OBJFILE is unloaded), otherwise return false. |
| 145 | OBJFILE must not be a separate debug info file. */ |
| 146 | virtual bool uses_objfile (struct objfile *objfile) const |
| 147 | { return false; } |
| 148 | |
| 149 | /* Generate agent expression bytecodes for this operation. */ |
| 150 | void generate_ax (struct expression *exp, struct agent_expr *ax, |
| 151 | struct axs_value *value, |
| 152 | struct type *cast_type = nullptr); |
| 153 | |
| 154 | /* Return the opcode that is implemented by this operation. */ |
| 155 | virtual enum exp_opcode opcode () const = 0; |
| 156 | |
| 157 | /* Print this operation to STREAM. */ |
| 158 | virtual void dump (struct ui_file *stream, int depth) const = 0; |
| 159 | |
| 160 | /* Call to indicate that this is the outermost operation in the |
| 161 | expression. This should almost never be overridden. */ |
| 162 | virtual void set_outermost () { } |
| 163 | |
| 164 | protected: |
| 165 | |
| 166 | /* A helper overload that wraps evaluate_subexp_do_call. */ |
| 167 | value *evaluate_funcall (struct type *expect_type, |
| 168 | struct expression *exp, |
| 169 | enum noside noside, |
| 170 | const char *function_name, |
| 171 | const std::vector<operation_up> &args); |
| 172 | |
| 173 | /* Called by generate_ax to do the work for this particular |
| 174 | operation. */ |
| 175 | virtual void do_generate_ax (struct expression *exp, |
| 176 | struct agent_expr *ax, |
| 177 | struct axs_value *value, |
| 178 | struct type *cast_type) |
| 179 | { |
| 180 | error (_("Cannot translate to agent expression")); |
| 181 | } |
| 182 | }; |
| 183 | |
| 184 | /* A helper function for creating an operation_up, given a type. */ |
| 185 | template<typename T, typename... Arg> |
| 186 | operation_up |
| 187 | make_operation (Arg... args) |
| 188 | { |
| 189 | return operation_up (new T (std::forward<Arg> (args)...)); |
| 190 | } |
| 191 | |
| 192 | } |
| 193 | |
| 194 | struct expression |
| 195 | { |
| 196 | expression (const struct language_defn *lang, struct gdbarch *arch) |
| 197 | : language_defn (lang), |
| 198 | gdbarch (arch) |
| 199 | { |
| 200 | } |
| 201 | |
| 202 | DISABLE_COPY_AND_ASSIGN (expression); |
| 203 | |
| 204 | /* Return the opcode for the outermost sub-expression of this |
| 205 | expression. */ |
| 206 | enum exp_opcode first_opcode () const |
| 207 | { |
| 208 | return op->opcode (); |
| 209 | } |
| 210 | |
| 211 | /* Evaluate the expression. EXPECT_TYPE is the context type of the |
| 212 | expression; normally this should be nullptr. NOSIDE controls how |
| 213 | evaluation is performed. */ |
| 214 | struct value *evaluate (struct type *expect_type, enum noside noside); |
| 215 | |
| 216 | /* Language it was entered in. */ |
| 217 | const struct language_defn *language_defn; |
| 218 | /* Architecture it was parsed in. */ |
| 219 | struct gdbarch *gdbarch; |
| 220 | expr::operation_up op; |
| 221 | }; |
| 222 | |
| 223 | typedef std::unique_ptr<expression> expression_up; |
| 224 | |
| 225 | /* From parse.c */ |
| 226 | |
| 227 | class innermost_block_tracker; |
| 228 | extern expression_up parse_expression (const char *, |
| 229 | innermost_block_tracker * = nullptr, |
| 230 | bool void_context_p = false); |
| 231 | |
| 232 | extern expression_up parse_expression_with_language (const char *string, |
| 233 | enum language lang); |
| 234 | |
| 235 | extern struct type *parse_expression_for_completion |
| 236 | (const char *, gdb::unique_xmalloc_ptr<char> *, enum type_code *); |
| 237 | |
| 238 | class innermost_block_tracker; |
| 239 | extern expression_up parse_exp_1 (const char **, CORE_ADDR pc, |
| 240 | const struct block *, int, |
| 241 | innermost_block_tracker * = nullptr); |
| 242 | |
| 243 | /* From eval.c */ |
| 244 | |
| 245 | /* Evaluate a function call. The function to be called is in CALLEE and |
| 246 | the arguments passed to the function are in ARGVEC. |
| 247 | FUNCTION_NAME is the name of the function, if known. |
| 248 | DEFAULT_RETURN_TYPE is used as the function's return type if the return |
| 249 | type is unknown. */ |
| 250 | |
| 251 | extern struct value *evaluate_subexp_do_call (expression *exp, |
| 252 | enum noside noside, |
| 253 | value *callee, |
| 254 | gdb::array_view<value *> argvec, |
| 255 | const char *function_name, |
| 256 | type *default_return_type); |
| 257 | |
| 258 | /* From expprint.c */ |
| 259 | |
| 260 | extern const char *op_name (enum exp_opcode opcode); |
| 261 | |
| 262 | extern void dump_prefix_expression (struct expression *, struct ui_file *); |
| 263 | |
| 264 | /* In an OP_RANGE expression, either bound could be empty, indicating |
| 265 | that its value is by default that of the corresponding bound of the |
| 266 | array or string. Also, the upper end of the range can be exclusive |
| 267 | or inclusive. So we have six sorts of subrange. This enumeration |
| 268 | type is to identify this. */ |
| 269 | |
| 270 | enum range_flag : unsigned |
| 271 | { |
| 272 | /* This is a standard range. Both the lower and upper bounds are |
| 273 | defined, and the bounds are inclusive. */ |
| 274 | RANGE_STANDARD = 0, |
| 275 | |
| 276 | /* The low bound was not given. */ |
| 277 | RANGE_LOW_BOUND_DEFAULT = 1 << 0, |
| 278 | |
| 279 | /* The high bound was not given. */ |
| 280 | RANGE_HIGH_BOUND_DEFAULT = 1 << 1, |
| 281 | |
| 282 | /* The high bound of this range is exclusive. */ |
| 283 | RANGE_HIGH_BOUND_EXCLUSIVE = 1 << 2, |
| 284 | |
| 285 | /* The range has a stride. */ |
| 286 | RANGE_HAS_STRIDE = 1 << 3, |
| 287 | }; |
| 288 | |
| 289 | DEF_ENUM_FLAGS_TYPE (enum range_flag, range_flags); |
| 290 | |
| 291 | #endif /* !defined (EXPRESSION_H) */ |