smatch_type_val.c

   1 /*
   2  * Copyright (C) 2013 Oracle.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License
   6  * as published by the Free Software Foundation; either version 2
   7  * of the License, or (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, see http://www.gnu.org/copyleft/gpl.txt
  16  */
  17
  18 /*
  19  * The plan here is to save all the possible values store to a given struct
  20  * member.
  21  *
  22  * We will load all the values in to the function_type_val table first then
  23  * run a script on that and load all the resulting values into the type_val
  24  * table.
  25  *
  26  * So in this file we want to take the union of everything assigned to the
  27  * struct member and insert it into the function_type_val at the end.
  28  *
  29  * You would think that we could use smatch_modification_hooks.c or
  30  * extra_modification_hook() here to get the information here but in the end we
  31  * need to code everything again a third time.
  32  *
  33  */
  34
  35 #include "smatch.h"
  36 #include "smatch_slist.h"
  37 #include "smatch_extra.h"
  38
  39 static int my_id;
  40
  41 struct stree_stack *fn_type_val_stack;
  42 struct stree *fn_type_val;
  43 struct stree *global_type_val;
  44
  45 static char *db_vals;
  46 static int get_vals(void *unused, int argc, char **argv, char **azColName)
  47 {
  48         db_vals = alloc_string(argv[0]);
  49         return 0;
  50 }
  51
  52 static void match_inline_start(struct expression *expr)
  53 {
  54         push_stree(&fn_type_val_stack, fn_type_val);
  55         fn_type_val = NULL;
  56 }
  57
  58 static void match_inline_end(struct expression *expr)
  59 {
  60         free_stree(&fn_type_val);
  61         fn_type_val = pop_stree(&fn_type_val_stack);
  62 }
  63
  64 int get_db_type_rl(struct expression *expr, struct range_list **rl)
  65 {
  66         char *member;
  67         struct range_list *tmp;
  68
  69         member = get_member_name(expr);
  70         if (!member)
  71                 return 0;
  72
  73         db_vals = NULL;
  74         run_sql(get_vals,
  75                 "select value from type_value where type = '%s';", member);
  76         free_string(member);
  77         if (!db_vals)
  78                 return 0;
  79         str_to_rl(&llong_ctype, db_vals, &tmp);
  80         tmp = cast_rl(get_type(expr), tmp);
  81         if (is_whole_rl(tmp))
  82                 return 0;
  83         *rl = tmp;
  84         free_string(db_vals);
  85
  86         return 1;
  87 }
  88
  89 static void add_type_val(char *member, struct range_list *rl)
  90 {
  91         struct smatch_state *old, *add, *new;
  92
  93         member = alloc_string(member);
  94         old = get_state_stree(fn_type_val, my_id, member, NULL);
  95         add = alloc_estate_rl(rl);
  96         if (old)
  97                 new = merge_estates(old, add);
  98         else
  99                 new = add;
 100         set_state_stree(&fn_type_val, my_id, member, NULL, new);
 101 }
 102
 103 static void add_fake_type_val(char *member, struct range_list *rl)
 104 {
 105         struct smatch_state *old, *add, *new;
 106
 107         member = alloc_string(member);
 108         old = get_state_stree(fn_type_val, my_id, member, NULL);
 109         add = alloc_estate_rl(rl);
 110         if (old) {
 111                 new = merge_estates(old, add);
 112         } else {
 113                 new = add;
 114                 new->name = alloc_string("min-max");
 115         }
 116         set_state_stree(&fn_type_val, my_id, member, NULL, new);
 117 }
 118
 119 static void add_global_type_val(char *member, struct range_list *rl)
 120 {
 121         struct smatch_state *old, *add, *new;
 122
 123         member = alloc_string(member);
 124         old = get_state_stree(global_type_val, my_id, member, NULL);
 125         add = alloc_estate_rl(rl);
 126         if (old)
 127                 new = merge_estates(old, add);
 128         else
 129                 new = add;
 130         new = clone_estate_perm(new);
 131         set_state_stree_perm(&global_type_val, my_id, member, NULL, new);
 132 }
 133
 134 static void match_assign_value(struct expression *expr)
 135 {
 136         char *member, *right_member;
 137         struct range_list *rl;
 138         struct symbol *type;
 139
 140         type = get_type(expr->left);
 141         if (type && type->type == SYM_STRUCT)
 142                 return;
 143
 144         member = get_member_name(expr->left);
 145         if (!member)
 146                 return;
 147
 148         /* if we're saying foo->mtu = bar->mtu then that doesn't add information */
 149         right_member = get_member_name(expr->right);
 150         if (right_member && strcmp(right_member, member) == 0)
 151                 goto free;
 152
 153         if (is_fake_call(expr->right)) {
 154                 add_fake_type_val(member, alloc_whole_rl(get_type(expr->left)));
 155                 goto free;
 156         }
 157
 158         if (expr->op != '=') {
 159                 add_type_val(member, alloc_whole_rl(get_type(expr->left)));
 160                 goto free;
 161         }
 162         get_absolute_rl(expr->right, &rl);
 163         rl = cast_rl(type, rl);
 164         add_type_val(member, rl);
 165 free:
 166         free_string(right_member);
 167         free_string(member);
 168 }
 169
 170 /*
 171  * If we too:  int *p = &my_struct->member then abandon all hope of tracking
 172  * my_struct->member.
 173  */
 174 static void match_assign_pointer(struct expression *expr)
 175 {
 176         struct expression *right;
 177         char *member;
 178         struct range_list *rl;
 179         struct symbol *type;
 180
 181         right = strip_expr(expr->right);
 182         if (right->type != EXPR_PREOP || right->op != '&')
 183                 return;
 184         right = strip_expr(right->unop);
 185
 186         member = get_member_name(right);
 187         if (!member)
 188                 return;
 189         type = get_type(right);
 190         rl = alloc_whole_rl(type);
 191         add_type_val(member, rl);
 192         free_string(member);
 193 }
 194
 195 static void match_global_assign(struct expression *expr)
 196 {
 197         char *member;
 198         struct range_list *rl;
 199
 200         member = get_member_name(expr->left);
 201         if (!member)
 202                 return;
 203         get_absolute_rl(expr->right, &rl);
 204         add_global_type_val(member, rl);
 205         free_string(member);
 206 }
 207
 208 static void unop_expr(struct expression *expr)
 209 {
 210         struct range_list *rl;
 211         char *member;
 212
 213         if (expr->op != SPECIAL_DECREMENT && expr->op != SPECIAL_INCREMENT)
 214                 return;
 215
 216         expr = strip_expr(expr->unop);
 217         member = get_member_name(expr);
 218         if (!member)
 219                 return;
 220         rl = alloc_whole_rl(get_type(expr));
 221         add_type_val(member, rl);
 222         free_string(member);
 223 }
 224
 225 static void asm_expr(struct statement *stmt)
 226 {
 227         struct expression *expr;
 228         struct range_list *rl;
 229         char *member;
 230         int state = 0;
 231
 232         FOR_EACH_PTR(stmt->asm_outputs, expr) {
 233                 switch (state) {
 234                 case 0: /* identifier */
 235                 case 1: /* constraint */
 236                         state++;
 237                         continue;
 238                 case 2: /* expression */
 239                         state = 0;
 240                         member = get_member_name(expr);
 241                         if (!member)
 242                                 continue;
 243                         rl = alloc_whole_rl(get_type(expr));
 244                         add_type_val(member, rl);
 245                         free_string(member);
 246                         continue;
 247                 }
 248         } END_FOR_EACH_PTR(expr);
 249 }
 250
 251 static void db_param_add(struct expression *expr, int param, char *key, char *value)
 252 {
 253         struct expression *arg;
 254         struct symbol *type;
 255         struct range_list *rl;
 256         char *member;
 257
 258         if (strcmp(key, "*$$") != 0)
 259                 return;
 260
 261         while (expr->type == EXPR_ASSIGNMENT)
 262                 expr = strip_expr(expr->right);
 263         if (expr->type != EXPR_CALL)
 264                 return;
 265
 266         arg = get_argument_from_call_expr(expr->args, param);
 267         arg = strip_expr(arg);
 268         if (!arg)
 269                 return;
 270         type = get_member_type_from_key(arg, key);
 271         if (arg->type != EXPR_PREOP || arg->op != '&')
 272                 return;
 273         arg = strip_expr(arg->unop);
 274
 275         member = get_member_name(arg);
 276         if (!member)
 277                 return;
 278         call_results_to_rl(expr, type, value, &rl);
 279         add_type_val(member, rl);
 280         free_string(member);
 281 }
 282
 283 static void match_end_func_info(struct symbol *sym)
 284 {
 285         struct sm_state *sm;
 286
 287         FOR_EACH_SM(fn_type_val, sm) {
 288                 sql_insert_function_type_value(sm->name, sm->state->name);
 289         } END_FOR_EACH_SM(sm);
 290
 291         free_stree(&fn_type_val);
 292 }
 293
 294 static void match_end_file(struct symbol_list *sym_list)
 295 {
 296         struct sm_state *sm;
 297
 298         FOR_EACH_SM(global_type_val, sm) {
 299                 sql_insert_function_type_value(sm->name, sm->state->name);
 300         } END_FOR_EACH_SM(sm);
 301 }
 302
 303 void register_type_val(int id)
 304 {
 305         if (!option_info)
 306                 return;
 307
 308         my_id = id;
 309
 310         add_hook(&match_assign_value, ASSIGNMENT_HOOK);
 311         add_hook(&match_assign_pointer, ASSIGNMENT_HOOK);
 312         add_hook(&unop_expr, OP_HOOK);
 313         add_hook(&asm_expr, ASM_HOOK);
 314         select_return_states_hook(ADDED_VALUE, &db_param_add);
 315
 316         add_hook(&match_inline_start, INLINE_FN_START);
 317         add_hook(&match_inline_end, INLINE_FN_END);
 318
 319         add_hook(&match_end_func_info, END_FUNC_HOOK);
 320
 321         add_hook(&match_global_assign, GLOBAL_ASSIGNMENT_HOOK);
 322         add_hook(&match_end_file, END_FILE_HOOK);
 323
 324 }