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, NULL,
  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         if (old && strcmp(old->name, "min-max") == 0)
 110                 return;
 111         add = alloc_estate_rl(rl);
 112         if (old) {
 113                 new = merge_estates(old, add);
 114         } else {
 115                 new = add;
 116                 new->name = alloc_string("min-max");
 117         }
 118         set_state_stree(&fn_type_val, my_id, member, NULL, new);
 119 }
 120
 121 static void add_global_type_val(char *member, struct range_list *rl)
 122 {
 123         struct smatch_state *old, *add, *new;
 124
 125         member = alloc_string(member);
 126         old = get_state_stree(global_type_val, my_id, member, NULL);
 127         add = alloc_estate_rl(rl);
 128         if (old)
 129                 new = merge_estates(old, add);
 130         else
 131                 new = add;
 132         new = clone_estate_perm(new);
 133         set_state_stree_perm(&global_type_val, my_id, member, NULL, new);
 134 }
 135
 136 static void match_assign_value(struct expression *expr)
 137 {
 138         char *member, *right_member;
 139         struct range_list *rl;
 140         struct symbol *type;
 141
 142         type = get_type(expr->left);
 143         if (type && type->type == SYM_STRUCT)
 144                 return;
 145
 146         member = get_member_name(expr->left);
 147         if (!member)
 148                 return;
 149
 150         /* if we're saying foo->mtu = bar->mtu then that doesn't add information */
 151         right_member = get_member_name(expr->right);
 152         if (right_member && strcmp(right_member, member) == 0)
 153                 goto free;
 154
 155         if (is_fake_call(expr->right)) {
 156                 add_fake_type_val(member, alloc_whole_rl(get_type(expr->left)));
 157                 goto free;
 158         }
 159
 160         if (expr->op != '=') {
 161                 add_type_val(member, alloc_whole_rl(get_type(expr->left)));
 162                 goto free;
 163         }
 164         get_absolute_rl(expr->right, &rl);
 165         rl = cast_rl(type, rl);
 166         add_type_val(member, rl);
 167 free:
 168         free_string(right_member);
 169         free_string(member);
 170 }
 171
 172 /*
 173  * If we too:  int *p = &my_struct->member then abandon all hope of tracking
 174  * my_struct->member.
 175  */
 176 static void match_assign_pointer(struct expression *expr)
 177 {
 178         struct expression *right;
 179         char *member;
 180         struct range_list *rl;
 181         struct symbol *type;
 182
 183         right = strip_expr(expr->right);
 184         if (right->type != EXPR_PREOP || right->op != '&')
 185                 return;
 186         right = strip_expr(right->unop);
 187
 188         member = get_member_name(right);
 189         if (!member)
 190                 return;
 191         type = get_type(right);
 192         rl = alloc_whole_rl(type);
 193         add_type_val(member, rl);
 194         free_string(member);
 195 }
 196
 197 static void match_global_assign(struct expression *expr)
 198 {
 199         char *member;
 200         struct range_list *rl;
 201
 202         member = get_member_name(expr->left);
 203         if (!member)
 204                 return;
 205         get_absolute_rl(expr->right, &rl);
 206         add_global_type_val(member, rl);
 207         free_string(member);
 208 }
 209
 210 static void unop_expr(struct expression *expr)
 211 {
 212         struct range_list *rl;
 213         char *member;
 214
 215         if (expr->op != SPECIAL_DECREMENT && expr->op != SPECIAL_INCREMENT)
 216                 return;
 217
 218         expr = strip_expr(expr->unop);
 219         member = get_member_name(expr);
 220         if (!member)
 221                 return;
 222         rl = alloc_whole_rl(get_type(expr));
 223         add_type_val(member, rl);
 224         free_string(member);
 225 }
 226
 227 static void asm_expr(struct statement *stmt)
 228 {
 229         struct expression *expr;
 230         struct range_list *rl;
 231         char *member;
 232         int state = 0;
 233
 234         FOR_EACH_PTR(stmt->asm_outputs, expr) {
 235                 switch (state) {
 236                 case 0: /* identifier */
 237                 case 1: /* constraint */
 238                         state++;
 239                         continue;
 240                 case 2: /* expression */
 241                         state = 0;
 242                         member = get_member_name(expr);
 243                         if (!member)
 244                                 continue;
 245                         rl = alloc_whole_rl(get_type(expr));
 246                         add_type_val(member, rl);
 247                         free_string(member);
 248                         continue;
 249                 }
 250         } END_FOR_EACH_PTR(expr);
 251 }
 252
 253 static void db_param_add(struct expression *expr, int param, char *key, char *value)
 254 {
 255         struct expression *arg;
 256         struct symbol *type;
 257         struct range_list *rl;
 258         char *member;
 259
 260         if (strcmp(key, "*$$") != 0)
 261                 return;
 262
 263         while (expr->type == EXPR_ASSIGNMENT)
 264                 expr = strip_expr(expr->right);
 265         if (expr->type != EXPR_CALL)
 266                 return;
 267
 268         arg = get_argument_from_call_expr(expr->args, param);
 269         arg = strip_expr(arg);
 270         if (!arg)
 271                 return;
 272         type = get_member_type_from_key(arg, key);
 273         if (arg->type != EXPR_PREOP || arg->op != '&')
 274                 return;
 275         arg = strip_expr(arg->unop);
 276
 277         member = get_member_name(arg);
 278         if (!member)
 279                 return;
 280         call_results_to_rl(expr, type, value, &rl);
 281         add_type_val(member, rl);
 282         free_string(member);
 283 }
 284
 285 static void match_end_func_info(struct symbol *sym)
 286 {
 287         struct sm_state *sm;
 288
 289         FOR_EACH_SM(fn_type_val, sm) {
 290                 sql_insert_function_type_value(sm->name, sm->state->name);
 291         } END_FOR_EACH_SM(sm);
 292
 293         free_stree(&fn_type_val);
 294 }
 295
 296 static void match_end_file(struct symbol_list *sym_list)
 297 {
 298         struct sm_state *sm;
 299
 300         FOR_EACH_SM(global_type_val, sm) {
 301                 sql_insert_function_type_value(sm->name, sm->state->name);
 302         } END_FOR_EACH_SM(sm);
 303 }
 304
 305 void register_type_val(int id)
 306 {
 307         if (!option_info)
 308                 return;
 309
 310         my_id = id;
 311
 312         add_hook(&match_assign_value, ASSIGNMENT_HOOK);
 313         add_hook(&match_assign_pointer, ASSIGNMENT_HOOK);
 314         add_hook(&unop_expr, OP_HOOK);
 315         add_hook(&asm_expr, ASM_HOOK);
 316         select_return_states_hook(ADDED_VALUE, &db_param_add);
 317
 318         add_hook(&match_inline_start, INLINE_FN_START);
 319         add_hook(&match_inline_end, INLINE_FN_END);
 320
 321         add_hook(&match_end_func_info, END_FUNC_HOOK);
 322
 323         add_hook(&match_global_assign, GLOBAL_ASSIGNMENT_HOOK);
 324         add_hook(&match_end_file, END_FILE_HOOK);
 325
 326 }