smatch_flow.c

   1 /*
   2  * sparse/smatch_flow.c
   3  *
   4  * Copyright (C) 2006,2008 Dan Carpenter.
   5  *
   6  *  Licensed under the Open Software License version 1.1
   7  *
   8  */
   9
  10 #include <stdio.h>
  11 #include "token.h"
  12 #include "smatch.h"
  13
  14 int __smatch_lineno = 0;
  15
  16 static char *filename;
  17 static char *cur_func;
  18 static int line_func_start;
  19
  20 char *get_filename() {  return filename; }
  21 char *get_function() { return cur_func; }
  22 int get_lineno() { return __smatch_lineno; }
  23 int get_func_pos() { return __smatch_lineno - line_func_start; }
  24
  25 static void split_statements(struct statement *stmt);
  26 static void split_symlist(struct symbol_list *sym_list);
  27 static void split_expr_list(struct expression_list *expr_list);
  28
  29 void __split_expr(struct expression *expr)
  30 {
  31         if (!expr)
  32                 return;
  33
  34         __smatch_lineno = expr->pos.line;
  35         __pass_to_client(expr, EXPR_HOOK);
  36
  37         // printf("%d Debug expr_type %d\n", get_lineno(), expr->type);
  38
  39         switch (expr->type) {
  40         case EXPR_PREOP:
  41         case EXPR_POSTOP:
  42                 if (expr->op == '*')
  43                         __pass_to_client(expr, DEREF_HOOK);
  44                 __split_expr(expr->unop);
  45                 return;
  46         case EXPR_STATEMENT:
  47                 split_statements(expr->statement);
  48                 return;
  49         case EXPR_BINOP:
  50         case EXPR_COMMA:
  51         case EXPR_COMPARE:
  52         case EXPR_LOGICAL:
  53         case EXPR_ASSIGNMENT:
  54                 if (expr->type == EXPR_ASSIGNMENT)
  55                         __pass_to_client(expr, ASSIGNMENT_HOOK);
  56                 __split_expr(expr->left);
  57                 __split_expr(expr->right);
  58                 if (expr->type == EXPR_ASSIGNMENT)
  59                         __pass_to_client(expr, ASSIGNMENT_AFTER_HOOK);
  60                 return;
  61         case EXPR_DEREF:
  62                 __pass_to_client(expr, DEREF_HOOK);
  63                 __split_expr(expr->deref);
  64                 return;
  65         case EXPR_SLICE:
  66                 __split_expr(expr->base);
  67                 return;
  68         case EXPR_CAST:
  69                 __split_expr(expr->cast_expression);
  70                 return;
  71         case EXPR_SIZEOF:
  72                 /* there isn't anything to pass a client from inside a sizeof() */
  73                 return;
  74         case EXPR_CONDITIONAL:
  75         case EXPR_SELECT:
  76                 __split_true_false_paths();
  77                 __split_whole_condition(expr->conditional);
  78                 __use_true_states();
  79                 __split_expr(expr->cond_true);
  80                 __use_false_states();
  81                 __split_expr(expr->cond_false);
  82                 __merge_true_states();
  83                 return;
  84         case EXPR_CALL:
  85                 __pass_to_client(expr, FUNCTION_CALL_HOOK);
  86                 __split_expr(expr->fn);
  87                 split_expr_list(expr->args);
  88                 __pass_to_client(expr, FUNCTION_CALL_AFTER_HOOK);
  89 #ifdef KERNEL
  90                 if (expr->fn->type == EXPR_SYMBOL &&
  91                     !strcmp(expr->fn->symbol_name->name, "panic"))
  92                         nullify_path();
  93 #endif
  94                 return;
  95         case EXPR_INITIALIZER:
  96                 split_expr_list(expr->expr_list);
  97                 return;
  98         case EXPR_IDENTIFIER:
  99                 __split_expr(expr->ident_expression);
 100                 return;
 101         case EXPR_INDEX:
 102                 __split_expr(expr->idx_expression);
 103                 return;
 104         case EXPR_POS:
 105                 __split_expr(expr->init_expr);
 106                 return;
 107         default:
 108                 return;
 109         };
 110 }
 111
 112 static int is_forever_loop(struct statement *stmt)
 113 {
 114
 115         struct expression *expr;
 116
 117         expr = stmt->iterator_pre_condition;
 118         if (!expr)
 119                 expr = stmt->iterator_post_condition;
 120         if (!expr) {
 121                 // this is a for(;;) loop...
 122                 return 1;
 123         }
 124
 125         if (expr->type == EXPR_VALUE && expr->value == 1) {
 126                 return 1;
 127         }
 128
 129         return 0;
 130 }
 131
 132 /*
 133  * Pre Loops are while and for loops.
 134  */
 135
 136 static void handle_pre_loop(struct statement *stmt)
 137 {
 138         split_statements(stmt->iterator_pre_statement);
 139
 140         __split_true_false_paths();
 141         __push_continues();
 142         __push_breaks();
 143         __prep_false_only_stack();
 144
 145         if (stmt->iterator_pre_condition) {
 146                 __split_whole_condition(stmt->iterator_pre_condition);
 147         }
 148         __use_true_states();
 149
 150         split_statements(stmt->iterator_statement);
 151         split_statements(stmt->iterator_post_statement);
 152         if (is_forever_loop(stmt)) {
 153                 __use_false_only_stack();
 154                 __pop_continues();
 155                 __pop_false_states();
 156                 nullify_path();
 157         } else {
 158                 __merge_continues();
 159                 __merge_false_states();
 160                 __use_false_only_stack();
 161         }
 162         __merge_breaks();
 163 }
 164
 165 /*
 166  * Post loops are do {} while();
 167  */
 168 static void handle_post_loop(struct statement *stmt)
 169 {
 170         __push_continues();
 171         __push_breaks();
 172         split_statements(stmt->iterator_statement);
 173
 174         __split_true_false_paths();
 175         __split_whole_condition(stmt->iterator_post_condition);
 176         /* It would prossibly be cleaner to make this all one function */
 177         __use_true_states();
 178         __use_false_states();
 179         __pop_true_states();
 180
 181         if (is_forever_loop(stmt)) {
 182                 __pop_continues();
 183                 nullify_path();
 184         } else {
 185                 __merge_continues();
 186         }
 187         __merge_breaks();
 188 }
 189
 190 static void split_statements(struct statement *stmt)
 191 {
 192         if (!stmt)
 193                 return;
 194
 195         __smatch_lineno = stmt->pos.line;
 196         __pass_to_client(stmt, STMT_HOOK);
 197
 198         switch (stmt->type) {
 199         case STMT_DECLARATION:
 200                 __pass_declarations_to_client(stmt->declaration);
 201                 split_symlist(stmt->declaration);
 202                 return;
 203         case STMT_RETURN:
 204                 __pass_to_client(stmt, RETURN_HOOK);
 205                 __split_expr(stmt->ret_value);
 206                 nullify_path();
 207                 return;
 208         case STMT_EXPRESSION:
 209                 __split_expr(stmt->expression);
 210                 return;
 211         case STMT_COMPOUND: {
 212                 struct statement *s;
 213                 FOR_EACH_PTR(stmt->stmts, s) {
 214                         split_statements(s);
 215                 } END_FOR_EACH_PTR(s);
 216                 return;
 217         }
 218         case STMT_IF:
 219                 __split_true_false_paths();
 220                 __split_whole_condition(stmt->if_conditional);
 221                 __use_true_states();
 222                 split_statements(stmt->if_true);
 223                 __use_false_states();
 224                 split_statements(stmt->if_false);
 225                 __merge_true_states();
 226                 return;
 227         case STMT_ITERATOR:
 228                 if (stmt->iterator_pre_condition)
 229                         handle_pre_loop(stmt);
 230                 else if (stmt->iterator_post_condition)
 231                         handle_post_loop(stmt);
 232                 else {
 233                         // these are for(;;) type loops.
 234                         handle_pre_loop(stmt);
 235                 }
 236                 return;
 237         case STMT_SWITCH:
 238                 __split_expr(stmt->switch_expression);
 239                 __save_switch_states();
 240                 __push_default();
 241                 __push_breaks();
 242                 nullify_path();
 243                 split_statements(stmt->switch_statement);
 244                 if (!__pop_default())
 245                         __merge_switches();
 246                 __pop_switches();
 247                 __merge_breaks();
 248                 return;
 249         case STMT_CASE:
 250                 __merge_switches();
 251                 if (!stmt->case_expression)
 252                         __set_default();
 253                 __split_expr(stmt->case_expression);
 254                 __split_expr(stmt->case_to);
 255                 split_statements(stmt->case_statement);
 256                 return;
 257         case STMT_LABEL:
 258                 if (stmt->label &&
 259                     stmt->label->type == SYM_LABEL &&
 260                     stmt->label->ident) {
 261                         __merge_gotos(stmt->label->ident->name);
 262                 }
 263                 split_statements(stmt->label_statement);
 264                 return;
 265         case STMT_GOTO:
 266                 __split_expr(stmt->goto_expression);
 267                 if (stmt->goto_label && stmt->goto_label->type == SYM_NODE) {
 268                         if (!strcmp(stmt->goto_label->ident->name, "break")) {
 269                                 __process_breaks();
 270                         } else if (!strcmp(stmt->goto_label->ident->name,
 271                                            "continue")) {
 272                                 __process_continues();
 273                         }
 274                 } else if (stmt->goto_label &&
 275                            stmt->goto_label->type == SYM_LABEL &&
 276                            stmt->goto_label->ident) {
 277                         __save_gotos(stmt->goto_label->ident->name);
 278                 }
 279                 nullify_path();
 280                 return;
 281         case STMT_NONE:
 282                 return;
 283         case STMT_ASM:
 284                 __split_expr(stmt->asm_string);
 285                 //__split_expr(stmt->asm_outputs);
 286                 //__split_expr(stmt->asm_inputs);
 287                 //__split_expr(stmt->asm_clobbers);
 288                 return;
 289         case STMT_CONTEXT:
 290                 return;
 291         case STMT_RANGE:
 292                 __split_expr(stmt->range_expression);
 293                 __split_expr(stmt->range_low);
 294                 __split_expr(stmt->range_high);
 295                 return;
 296         }
 297 }
 298
 299 static void split_expr_list(struct expression_list *expr_list)
 300 {
 301         struct expression *expr;
 302         FOR_EACH_PTR(expr_list, expr) {
 303                 __split_expr(expr);
 304         } END_FOR_EACH_PTR(expr);
 305 }
 306
 307
 308 static void split_sym(struct symbol *sym)
 309 {
 310         if (!sym)
 311                 return;
 312         if (!(sym->namespace & NS_SYMBOL))
 313                 return;
 314
 315         __pass_to_client(sym, SYM_HOOK);
 316         split_statements(sym->stmt);
 317         __split_expr(sym->array_size);
 318         split_symlist(sym->arguments);
 319         split_symlist(sym->symbol_list);
 320         split_statements(sym->inline_stmt);
 321         split_symlist(sym->inline_symbol_list);
 322         __split_expr(sym->initializer);
 323 }
 324
 325 static void split_symlist(struct symbol_list *sym_list)
 326 {
 327         struct symbol *sym;
 328
 329         FOR_EACH_PTR(sym_list, sym) {
 330                 split_sym(sym);
 331         } END_FOR_EACH_PTR(sym);
 332 }
 333
 334 static void split_functions(struct symbol_list *sym_list)
 335 {
 336         struct symbol *sym;
 337
 338         FOR_EACH_PTR(sym_list, sym) {
 339                 struct symbol *base_type;
 340                 base_type = get_base_type(sym);
 341                 if (sym->type == SYM_NODE && base_type->type == SYM_FN) {
 342                         if (base_type->stmt)
 343                                 line_func_start = base_type->stmt->pos.line;
 344                         if (sym->ident)
 345                                 cur_func = sym->ident->name;
 346                         __smatch_lineno = sym->pos.line;
 347                         __pass_to_client(sym, FUNC_DEF_HOOK);
 348                         split_statements(base_type->stmt);
 349                         __pass_to_client(sym, END_FUNC_HOOK);
 350                         cur_func = NULL;
 351                         line_func_start = 0;
 352                         clear_all_states();
 353
 354                 } else {
 355                         __pass_to_client(sym, BASE_HOOK);
 356                 }
 357         } END_FOR_EACH_PTR(sym);
 358 }
 359
 360 void smatch (int argc, char **argv)
 361 {
 362
 363         struct string_list *filelist = NULL;
 364         struct symbol_list *sym_list;
 365
 366         if (argc < 2) {
 367                 printf("Usage:  smatch <filename.c>\n");
 368                 exit(1);
 369         }
 370         sparse_initialize(argc, argv, &filelist);
 371         FOR_EACH_PTR_NOTAG(filelist, filename) {
 372                 sym_list = __sparse(filename);
 373                 split_functions(sym_list);
 374         } END_FOR_EACH_PTR_NOTAG(filename);
 375 }