smatch_type_val.c

   1 /*
   2  * sparse/smatch_type_val.c
   3  *
   4  * Copyright (C) 2013 Oracle.
   5  *
   6  * Licensed under the Open Software License version 1.1
   7  *
   8  */
   9
  10 /*
  11  * The plan here is to save all the possible values store to a given struct
  12  * member.
  13  *
  14  * We will load all the values in to the function_type_val table first then
  15  * run a script on that and load all the resulting values into the type_val
  16  * table.
  17  *
  18  * So in this file we want to take the union of everything assigned to the
  19  * struct member and insert it into the function_type_val at the end.
  20  *
  21  * You would think that we could use smatch_modification_hooks.c or
  22  * extra_modification_hook() here to get the information here but in the end we
  23  * need to code everything again a third time.
  24  *
  25  */
  26
  27 #include "smatch.h"
  28 #include "smatch_slist.h"
  29 #include "smatch_extra.h"
  30
  31 static int my_id;
  32
  33 struct state_list_stack *fn_type_val_stack;
  34 struct state_list *fn_type_val;
  35 struct state_list *global_type_val;
  36
  37 static char *db_vals;
  38 static int get_vals(void *unused, int argc, char **argv, char **azColName)
  39 {
  40         db_vals = alloc_string(argv[0]);
  41         return 0;
  42 }
  43
  44 static void match_inline_start(struct expression *expr)
  45 {
  46         push_slist(&fn_type_val_stack, fn_type_val);
  47         fn_type_val = NULL;
  48 }
  49
  50 static void match_inline_end(struct expression *expr)
  51 {
  52         fn_type_val = pop_slist(&fn_type_val_stack);
  53 }
  54
  55 int get_db_type_rl(struct expression *expr, struct range_list **rl)
  56 {
  57         char *member;
  58         struct range_list *tmp;
  59
  60         member = get_member_name(expr);
  61         if (!member)
  62                 return 0;
  63
  64         db_vals = NULL;
  65         run_sql(get_vals,
  66                 "select value from type_value where type = '%s'", member);
  67         free_string(member);
  68         if (!db_vals)
  69                 return 0;
  70         str_to_rl(&llong_ctype, db_vals, &tmp);
  71         tmp = cast_rl(get_type(expr), tmp);
  72         if (is_whole_rl(tmp))
  73                 return 0;
  74         *rl = tmp;
  75         free_string(db_vals);
  76
  77         return 1;
  78 }
  79
  80 /*
  81  * One of the complications is that smatch tries to free a bunch of data at the
  82  * end of every function.
  83  */
  84 static struct data_info *clone_dinfo_perm(struct data_info *dinfo)
  85 {
  86         struct data_info *ret;
  87
  88         ret = malloc(sizeof(*ret));
  89         ret->related = NULL;
  90         ret->value_ranges = clone_rl_permanent(dinfo->value_ranges);
  91         ret->hard_max = 0;
  92         return ret;
  93 }
  94
  95 static struct smatch_state *clone_estate_perm(struct smatch_state *state)
  96 {
  97         struct smatch_state *ret;
  98
  99         ret = malloc(sizeof(*ret));
 100         ret->name = alloc_string(state->name);
 101         ret->data = clone_dinfo_perm(get_dinfo(state));
 102         return ret;
 103 }
 104
 105 static void set_state_slist_perm(struct state_list **slist, int owner, const char *name,
 106                      struct symbol *sym, struct smatch_state *state)
 107 {
 108         struct sm_state *sm;
 109
 110         sm = malloc(sizeof(*sm));
 111         memset(sm, 0, sizeof(*sm));
 112         sm->owner = owner;
 113         sm->name = name;
 114         sm->sym = sym;
 115         sm->state = state;
 116
 117         overwrite_sm_state(slist, sm);
 118 }
 119
 120 static void add_type_val(char *member, struct range_list *rl)
 121 {
 122         struct smatch_state *old, *add, *new;
 123
 124         member = alloc_string(member);
 125         old = get_state_slist(fn_type_val, my_id, member, NULL);
 126         add = alloc_estate_rl(rl);
 127         if (old)
 128                 new = merge_estates(old, add);
 129         else
 130                 new = add;
 131         set_state_slist(&fn_type_val, my_id, member, NULL, new);
 132 }
 133
 134 static void add_global_type_val(char *member, struct range_list *rl)
 135 {
 136         struct smatch_state *old, *add, *new;
 137
 138         member = alloc_string(member);
 139         old = get_state_slist(global_type_val, my_id, member, NULL);
 140         add = alloc_estate_rl(rl);
 141         if (old)
 142                 new = merge_estates(old, add);
 143         else
 144                 new = add;
 145         new = clone_estate_perm(new);
 146         set_state_slist_perm(&global_type_val, my_id, member, NULL, new);
 147 }
 148
 149 static void match_assign_value(struct expression *expr)
 150 {
 151         char *member, *right_member;
 152         struct range_list *rl;
 153         struct symbol *type;
 154
 155         type = get_type(expr->left);
 156         if (type && type->type == SYM_STRUCT)
 157                 return;
 158
 159         member = get_member_name(expr->left);
 160         if (!member)
 161                 return;
 162
 163         /* if we're saying foo->mtu = bar->mtu then that doesn't add information */
 164         right_member = get_member_name(expr->right);
 165         if (right_member && strcmp(right_member, member) == 0)
 166                 goto free;
 167
 168         if (expr->op != '=') {
 169                 add_type_val(member, alloc_whole_rl(get_type(expr->left)));
 170                 goto free;
 171         }
 172         get_absolute_rl(expr->right, &rl);
 173         rl = cast_rl(type, rl);
 174         add_type_val(member, rl);
 175 free:
 176         free_string(right_member);
 177         free_string(member);
 178 }
 179
 180 /*
 181  * If we too:  int *p = &my_struct->member then abandon all hope of tracking
 182  * my_struct->member.
 183  */
 184 static void match_assign_pointer(struct expression *expr)
 185 {
 186         struct expression *right;
 187         char *member;
 188         struct range_list *rl;
 189         struct symbol *type;
 190
 191         right = strip_expr(expr->right);
 192         if (right->type != EXPR_PREOP || right->op != '&')
 193                 return;
 194         right = strip_expr(right->unop);
 195
 196         member = get_member_name(right);
 197         if (!member)
 198                 return;
 199         type = get_type(right);
 200         rl = alloc_whole_rl(type);
 201         add_type_val(member, rl);
 202         free_string(member);
 203 }
 204
 205 static void match_global_assign(struct expression *expr)
 206 {
 207         char *member;
 208         struct range_list *rl;
 209
 210         member = get_member_name(expr->left);
 211         if (!member)
 212                 return;
 213         get_absolute_rl(expr->right, &rl);
 214         add_global_type_val(member, rl);
 215         free_string(member);
 216 }
 217
 218 static void unop_expr(struct expression *expr)
 219 {
 220         struct range_list *rl;
 221         char *member;
 222
 223         if (expr->op != SPECIAL_DECREMENT && expr->op != SPECIAL_INCREMENT)
 224                 return;
 225
 226         expr = strip_expr(expr->unop);
 227         member = get_member_name(expr);
 228         if (!member)
 229                 return;
 230         rl = alloc_whole_rl(get_type(expr));
 231         add_type_val(member, rl);
 232         free_string(member);
 233 }
 234
 235 static void asm_expr(struct statement *stmt)
 236 {
 237         struct expression *expr;
 238         struct range_list *rl;
 239         char *member;
 240         int state = 0;
 241
 242         FOR_EACH_PTR(stmt->asm_outputs, expr) {
 243                 switch (state) {
 244                 case 0: /* identifier */
 245                 case 1: /* constraint */
 246                         state++;
 247                         continue;
 248                 case 2: /* expression */
 249                         state = 0;
 250                         member = get_member_name(expr);
 251                         if (!member)
 252                                 continue;
 253                         rl = alloc_whole_rl(get_type(expr));
 254                         add_type_val(member, rl);
 255                         free_string(member);
 256                         continue;
 257                 }
 258         } END_FOR_EACH_PTR(expr);
 259 }
 260
 261 static void db_param_add(struct expression *expr, int param, char *key, char *value)
 262 {
 263         struct expression *arg;
 264         struct symbol *type;
 265         struct range_list *rl;
 266         char *member;
 267
 268         if (strcmp(key, "*$$") != 0)
 269                 return;
 270
 271         while (expr->type == EXPR_ASSIGNMENT)
 272                 expr = strip_expr(expr->right);
 273         if (expr->type != EXPR_CALL)
 274                 return;
 275
 276         arg = get_argument_from_call_expr(expr->args, param);
 277         arg = strip_expr(arg);
 278         if (!arg)
 279                 return;
 280         type = get_member_type_from_key(arg, key);
 281         if (arg->type != EXPR_PREOP || arg->op != '&')
 282                 return;
 283         arg = strip_expr(arg->unop);
 284
 285         member = get_member_name(arg);
 286         if (!member)
 287                 return;
 288         call_results_to_rl(expr, type, value, &rl);
 289         add_type_val(member, rl);
 290         free_string(member);
 291 }
 292
 293 static void match_end_func_info(struct symbol *sym)
 294 {
 295         struct sm_state *sm;
 296
 297         FOR_EACH_PTR(fn_type_val, sm) {
 298                 sql_insert_function_type_value(sm->name, sm->state->name);
 299         } END_FOR_EACH_PTR(sm);
 300
 301         free_slist(&fn_type_val);
 302 }
 303
 304 static void match_end_file(struct symbol_list *sym_list)
 305 {
 306         struct sm_state *sm;
 307
 308         FOR_EACH_PTR(global_type_val, sm) {
 309                 sql_insert_function_type_value(sm->name, sm->state->name);
 310         } END_FOR_EACH_PTR(sm);
 311 }
 312
 313 void register_type_val(int id)
 314 {
 315         if (!option_info)
 316                 return;
 317
 318         my_id = id;
 319
 320         add_hook(&match_assign_value, ASSIGNMENT_HOOK);
 321         add_hook(&match_assign_pointer, ASSIGNMENT_HOOK);
 322         add_hook(&unop_expr, OP_HOOK);
 323         add_hook(&asm_expr, ASM_HOOK);
 324         select_return_states_hook(ADDED_VALUE, &db_param_add);
 325
 326         add_hook(&match_inline_start, INLINE_FN_START);
 327         add_hook(&match_inline_end, INLINE_FN_END);
 328
 329         add_hook(&match_end_func_info, END_FUNC_HOOK);
 330
 331         add_hook(&match_global_assign, GLOBAL_ASSIGNMENT_HOOK);
 332         add_hook(&match_end_file, END_FILE_HOOK);
 333
 334 }