1 #ifndef EXPRESSION_H
2 #define EXPRESSION_H
3 /*
4 * sparse/expression.h
5 *
6 * Copyright (C) 2003 Transmeta Corp.
7 * 2003 Linus Torvalds
8 *
9 * Permission is hereby granted, free of charge, to any person obtaining a copy
10 * of this software and associated documentation files (the "Software"), to deal
11 * in the Software without restriction, including without limitation the rights
12 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
13 * copies of the Software, and to permit persons to whom the Software is
14 * furnished to do so, subject to the following conditions:
15 *
16 * The above copyright notice and this permission notice shall be included in
17 * all copies or substantial portions of the Software.
18 *
19 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
20 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
21 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
22 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
23 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
24 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
25 * THE SOFTWARE.
26 *
27 * Declarations and helper functions for expression parsing.
28 */
29
30 #include "allocate.h"
31 #include "lib.h"
32 #include "symbol.h"
33
34 struct expression_list;
35
36 enum expression_type {
37 EXPR_VALUE = 1,
38 EXPR_STRING,
39 EXPR_SYMBOL,
40 EXPR_TYPE,
41 EXPR_BINOP,
42 EXPR_ASSIGNMENT,
43 EXPR_LOGICAL,
44 EXPR_DEREF,
45 EXPR_PREOP,
46 EXPR_POSTOP,
47 EXPR_CAST,
48 EXPR_FORCE_CAST,
49 EXPR_IMPLIED_CAST,
50 EXPR_SIZEOF,
51 EXPR_ALIGNOF,
52 EXPR_PTRSIZEOF,
53 EXPR_CONDITIONAL,
54 EXPR_SELECT, // a "safe" conditional expression
55 EXPR_STATEMENT,
56 EXPR_CALL,
57 EXPR_COMMA,
58 EXPR_COMPARE,
59 EXPR_LABEL,
60 EXPR_INITIALIZER, // initializer list
61 EXPR_IDENTIFIER, // identifier in initializer
62 EXPR_INDEX, // index in initializer
63 EXPR_POS, // position in initializer
64 EXPR_FVALUE,
65 EXPR_SLICE,
66 EXPR_OFFSETOF,
67 EXPR_ASM_OPERAND,
68 };
69
70
71 /*
72 * Flags for tracking the promotion of constness related attributes
73 * from subexpressions to their parents.
74 *
75 * The flags are not independent as one might imply another.
76 * The implications are as follows:
77 * - CEF_INT, CEF_ENUM and
78 * CEF_CHAR imply CEF_ICE.
79 *
80 * Use the CEF_*_SET_MASK and CEF_*_CLEAR_MASK
81 * helper macros defined below to set or clear one of these flags.
82 */
83 enum constexpr_flag {
84 CEF_NONE = 0,
85 /*
86 * A constant in the sense of [6.4.4]:
87 * - Integer constant [6.4.4.1]
88 * - Floating point constant [6.4.4.2]
89 * - Enumeration constant [6.4.4.3]
90 * - Character constant [6.4.4.4]
91 */
92 CEF_INT = (1 << 0),
93 CEF_FLOAT = (1 << 1),
94 CEF_ENUM = (1 << 2),
95 CEF_CHAR = (1 << 3),
96
97 /*
98 * A constant expression in the sense of [6.6]:
99 * - integer constant expression [6.6(6)]
100 * - arithmetic constant expression [6.6(8)]
101 * - address constant [6.6(9)]
102 */
103 CEF_ICE = (1 << 4),
104 CEF_ACE = (1 << 5),
105 CEF_ADDR = (1 << 6),
106
107 /* integer constant expression => arithmetic constant expression */
108 CEF_SET_ICE = (CEF_ICE | CEF_ACE),
109
110 /* integer constant => integer constant expression */
111 CEF_SET_INT = (CEF_INT | CEF_SET_ICE),
112
113 /* floating point constant => arithmetic constant expression */
114 CEF_SET_FLOAT = (CEF_FLOAT | CEF_ACE),
115
116 /* enumeration constant => integer constant expression */
117 CEF_SET_ENUM = (CEF_ENUM | CEF_SET_ICE),
118
119 /* character constant => integer constant expression */
120 CEF_SET_CHAR = (CEF_CHAR | CEF_SET_ICE),
121
122 /*
123 * Remove any "Constant" [6.4.4] flag, but retain the "constant
124 * expression" [6.6] flags.
125 */
126 CEF_CONST_MASK = (CEF_INT | CEF_FLOAT | CEF_CHAR),
127
128 /*
129 * not an integer constant expression => neither of integer,
130 * enumeration and character constant
131 */
132 CEF_CLR_ICE = (CEF_ICE | CEF_INT | CEF_ENUM | CEF_CHAR),
133 };
134
135 enum {
136 Handled = 1 << 0,
137 Fake = 1 << 1,
138 }; /* for expr->flags */
139
140 enum {
141 Taint_comma = 1,
142 }; /* for expr->taint */
143
144 struct expression {
145 enum expression_type type:8;
146 unsigned flags:8;
147 unsigned smatch_flags:16;
148 int op;
149 struct position pos;
150 struct symbol *ctype;
151 unsigned long parent;
152 union {
153 // EXPR_VALUE
154 struct {
155 unsigned long long value;
156 unsigned taint;
157 };
158
159 // EXPR_FVALUE
160 long double fvalue;
161
162 // EXPR_STRING
163 struct {
164 int wide;
165 struct string *string;
166 };
167
168 // EXPR_UNOP, EXPR_PREOP and EXPR_POSTOP
169 struct /* unop */ {
170 struct expression *unop;
171 unsigned long op_value;
172 };
173
174 // EXPR_SYMBOL, EXPR_TYPE
175 struct /* symbol_arg */ {
176 struct symbol *symbol;
177 struct ident *symbol_name;
178 };
179
180 // EXPR_STATEMENT
181 struct statement *statement;
182
183 // EXPR_BINOP, EXPR_COMMA, EXPR_COMPARE, EXPR_LOGICAL and EXPR_ASSIGNMENT
184 struct /* binop_arg */ {
185 struct expression *left, *right;
186 };
187 // EXPR_DEREF
188 struct /* deref_arg */ {
189 struct expression *deref;
190 struct ident *member;
191 int member_offset;
192 };
193 // EXPR_SLICE
194 struct /* slice */ {
195 struct expression *base;
196 unsigned r_bitpos, r_nrbits;
197 };
198 // EXPR_CAST, EXPR_FORCE_CAST, EXPR_IMPLIED_CAST,
199 // EXPR_SIZEOF, EXPR_ALIGNOF and EXPR_PTRSIZEOF
200 struct /* cast_arg */ {
201 struct symbol *cast_type;
202 struct expression *cast_expression;
203 };
204 // EXPR_CONDITIONAL
205 // EXPR_SELECT
206 struct /* conditional_expr */ {
207 struct expression *conditional, *cond_true, *cond_false;
208 };
209 // EXPR_CALL
210 struct /* call_expr */ {
211 struct expression *fn;
212 struct expression_list *args;
213 };
214 // EXPR_LABEL
215 struct /* label_expr */ {
216 struct symbol *label_symbol;
217 };
218 // EXPR_INITIALIZER
219 struct expression_list *expr_list;
220 // EXPR_IDENTIFIER
221 struct /* ident_expr */ {
222 int offset;
223 struct ident *expr_ident;
224 struct symbol *field;
225 struct expression *ident_expression;
226 };
227 // EXPR_INDEX
228 struct /* index_expr */ {
229 unsigned int idx_from, idx_to;
230 struct expression *idx_expression;
231 };
232 // EXPR_POS
233 struct /* initpos_expr */ {
234 unsigned int init_offset, init_nr;
235 struct expression *init_expr;
236 };
237 // EXPR_OFFSETOF
238 struct {
239 struct symbol *in;
240 struct expression *down;
241 union {
242 struct ident *ident;
243 struct expression *index;
244 };
245 };
246 // EXPR_ASM_OPERAND
247 struct {
248 struct ident *name;
249 struct expression *constraint;
250 struct expression *expr;
251 };
252 };
253 };
254
255 ///
256 // Constant expression values
257 // --------------------------
258
259 ///
260 // test if an expression evaluates to the constant ``0``.
261 // @return: ``1`` if @expr evaluate to ``0``,
262 // ``0`` otherwise.
263 int is_zero_constant(struct expression *expr);
264
265 ///
266 // test the compile time truth value of an expression
267 // @return:
268 // * ``-1`` if @expr is not constant,
269 // * ``0`` or ``1`` depending on the truth value of @expr.
270 int expr_truth_value(struct expression *expr);
271
272 long long get_expression_value(struct expression *);
273 long long const_expression_value(struct expression *);
274 long long get_expression_value_silent(struct expression *expr);
275
276 /* Expression parsing */
277 struct token *parse_expression(struct token *token, struct expression **tree);
278 struct token *conditional_expression(struct token *token, struct expression **tree);
279 struct token *primary_expression(struct token *token, struct expression **tree);
280 struct token *parens_expression(struct token *token, struct expression **expr, const char *where);
281 struct token *assignment_expression(struct token *token, struct expression **tree);
282
283 extern void evaluate_symbol_list(struct symbol_list *list);
284 extern struct symbol *evaluate_statement(struct statement *stmt);
285 extern struct symbol *evaluate_expression(struct expression *);
286 struct symbol *find_identifier(struct ident *ident, struct symbol_list *_list, int *offset);
287
288 extern int expand_symbol(struct symbol *);
289
290 static inline struct expression *alloc_expression(struct position pos, int type)
291 {
292 struct expression *expr = __alloc_expression(0);
293 expr->type = type;
294 expr->pos = pos;
295 expr->flags = CEF_NONE;
296 return expr;
297 }
298
299 static inline struct expression *alloc_const_expression(struct position pos, int value)
300 {
301 struct expression *expr = __alloc_expression(0);
302 expr->type = EXPR_VALUE;
303 expr->pos = pos;
304 expr->value = value;
305 expr->ctype = &int_ctype;
306 expr->flags = CEF_SET_INT;
307 return expr;
308 }
309
310 /* Type name parsing */
311 struct token *typename(struct token *, struct symbol **, int *);
312
313 static inline int lookup_type(struct token *token)
314 {
315 if (token->pos.type == TOKEN_IDENT) {
316 struct symbol *sym = lookup_symbol(token->ident, NS_SYMBOL | NS_TYPEDEF);
317 return sym && (sym->namespace & NS_TYPEDEF);
318 }
319 return 0;
320 }
321
322 /* Statement parsing */
323 struct statement *alloc_statement(struct position pos, int type);
324 struct token *initializer(struct expression **tree, struct token *token);
325 struct token *compound_statement(struct token *, struct statement *);
326
327 /* The preprocessor calls this 'constant_expression()' */
328 #define constant_expression(token,tree) conditional_expression(token, tree)
329
330 /* Cast folding of constant values.. */
331 void cast_value(struct expression *expr, struct symbol *newtype,
332 struct expression *old, struct symbol *oldtype);
333
334 #endif