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 Tmp = 1 << 1,
138 Fake = 1 << 2,
139 }; /* for expr->smatch_flags */
140
141 enum {
142 Taint_comma = 1,
143 }; /* for expr->taint */
144
145 struct expression {
146 enum expression_type type:8;
147 unsigned flags:8;
148 unsigned smatch_flags:16;
149 int op;
150 struct position pos;
151 struct symbol *ctype;
152 unsigned long parent;
153 union {
154 // EXPR_VALUE
155 struct {
156 unsigned long long value;
157 unsigned taint;
158 };
159
160 // EXPR_FVALUE
161 long double fvalue;
162
163 // EXPR_STRING
164 struct {
165 int wide;
166 struct string *string;
167 };
168
169 // EXPR_UNOP, EXPR_PREOP and EXPR_POSTOP
170 struct /* unop */ {
171 struct expression *unop;
172 unsigned long op_value;
173 };
174
175 // EXPR_SYMBOL, EXPR_TYPE
176 struct /* symbol_arg */ {
177 struct symbol *symbol;
178 struct ident *symbol_name;
179 };
180
181 // EXPR_STATEMENT
182 struct statement *statement;
183
184 // EXPR_BINOP, EXPR_COMMA, EXPR_COMPARE, EXPR_LOGICAL and EXPR_ASSIGNMENT
185 struct /* binop_arg */ {
186 struct expression *left, *right;
187 };
188 // EXPR_DEREF
189 struct /* deref_arg */ {
190 struct expression *deref;
191 struct ident *member;
192 int member_offset;
193 };
194 // EXPR_SLICE
195 struct /* slice */ {
196 struct expression *base;
197 unsigned r_bitpos, r_nrbits;
198 };
199 // EXPR_CAST, EXPR_FORCE_CAST, EXPR_IMPLIED_CAST,
200 // EXPR_SIZEOF, EXPR_ALIGNOF and EXPR_PTRSIZEOF
201 struct /* cast_arg */ {
202 struct symbol *cast_type;
203 struct expression *cast_expression;
204 };
205 // EXPR_CONDITIONAL
206 // EXPR_SELECT
207 struct /* conditional_expr */ {
208 struct expression *conditional, *cond_true, *cond_false;
209 };
210 // EXPR_CALL
211 struct /* call_expr */ {
212 struct expression *fn;
213 struct expression_list *args;
214 };
215 // EXPR_LABEL
216 struct /* label_expr */ {
217 struct symbol *label_symbol;
218 };
219 // EXPR_INITIALIZER
220 struct expression_list *expr_list;
221 // EXPR_IDENTIFIER
222 struct /* ident_expr */ {
223 int offset;
224 struct ident *expr_ident;
225 struct symbol *field;
226 struct expression *ident_expression;
227 };
228 // EXPR_INDEX
229 struct /* index_expr */ {
230 unsigned int idx_from, idx_to;
231 struct expression *idx_expression;
232 };
233 // EXPR_POS
234 struct /* initpos_expr */ {
235 unsigned int init_offset, init_nr;
236 struct expression *init_expr;
237 };
238 // EXPR_OFFSETOF
239 struct {
240 struct symbol *in;
241 struct expression *down;
242 union {
243 struct ident *ident;
244 struct expression *index;
245 };
246 };
247 // EXPR_ASM_OPERAND
248 struct {
249 struct ident *name;
250 struct expression *constraint;
251 struct expression *expr;
252 };
253 };
254 };
255
256 ///
257 // Constant expression values
258 // --------------------------
259
260 ///
261 // test if an expression evaluates to the constant ``0``.
262 // @return: ``1`` if @expr evaluate to ``0``,
263 // ``0`` otherwise.
264 int is_zero_constant(struct expression *expr);
265
266 ///
267 // test the compile time truth value of an expression
268 // @return:
269 // * ``-1`` if @expr is not constant,
270 // * ``0`` or ``1`` depending on the truth value of @expr.
271 int expr_truth_value(struct expression *expr);
272
273 long long get_expression_value(struct expression *);
274 long long const_expression_value(struct expression *);
275 long long get_expression_value_silent(struct expression *expr);
276
277 /* Expression parsing */
278 struct token *parse_expression(struct token *token, struct expression **tree);
279 struct token *conditional_expression(struct token *token, struct expression **tree);
280 struct token *primary_expression(struct token *token, struct expression **tree);
281 struct token *parens_expression(struct token *token, struct expression **expr, const char *where);
282 struct token *assignment_expression(struct token *token, struct expression **tree);
283
284 extern void evaluate_symbol_list(struct symbol_list *list);
285 extern struct symbol *evaluate_statement(struct statement *stmt);
286 extern struct symbol *evaluate_expression(struct expression *);
287 struct symbol *find_identifier(struct ident *ident, struct symbol_list *_list, int *offset);
288
289 extern int expand_symbol(struct symbol *);
290
alloc_expression(struct position pos,int type)291 static inline struct expression *alloc_expression(struct position pos, int type)
292 {
293 struct expression *expr = __alloc_expression(0);
294 expr->type = type;
295 expr->pos = pos;
296 expr->flags = CEF_NONE;
297 return expr;
298 }
299
alloc_const_expression(struct position pos,int value)300 static inline struct expression *alloc_const_expression(struct position pos, int value)
301 {
302 struct expression *expr = __alloc_expression(0);
303 expr->type = EXPR_VALUE;
304 expr->pos = pos;
305 expr->value = value;
306 expr->ctype = &int_ctype;
307 expr->flags = CEF_SET_INT;
308 return expr;
309 }
310
311 /* Type name parsing */
312 struct token *typename(struct token *, struct symbol **, int *);
313
lookup_type(struct token * token)314 static inline int lookup_type(struct token *token)
315 {
316 if (token->pos.type == TOKEN_IDENT) {
317 struct symbol *sym = lookup_symbol(token->ident, NS_SYMBOL | NS_TYPEDEF);
318 return sym && (sym->namespace & NS_TYPEDEF);
319 }
320 return 0;
321 }
322
323 /* Statement parsing */
324 struct statement *alloc_statement(struct position pos, int type);
325 struct token *initializer(struct expression **tree, struct token *token);
326 struct token *compound_statement(struct token *, struct statement *);
327
328 /* The preprocessor calls this 'constant_expression()' */
329 #define constant_expression(token,tree) conditional_expression(token, tree)
330
331 /* Cast folding of constant values.. */
332 void cast_value(struct expression *expr, struct symbol *newtype,
333 struct expression *old, struct symbol *oldtype);
334
335 #endif
336