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         // printf("%d Debug expr_type %d\n", get_lineno(), expr->type);
  35
  36         __smatch_lineno = expr->pos.line;
  37         __pass_to_client(expr, EXPR_HOOK);
  38
  39         switch (expr->type) {
  40         case EXPR_PREOP:
  41         case EXPR_POSTOP:
  42                 __pass_to_client(expr, OP_HOOK);
  43                 __split_expr(expr->unop);
  44                 return;
  45         case EXPR_STATEMENT:
  46                 split_statements(expr->statement);
  47                 return;
  48         case EXPR_BINOP:
  49         case EXPR_COMMA:
  50         case EXPR_COMPARE:
  51         case EXPR_LOGICAL:
  52         case EXPR_ASSIGNMENT:
  53                 if (expr->type == EXPR_ASSIGNMENT)
  54                         __pass_to_client(expr, ASSIGNMENT_HOOK);
  55                 __split_expr(expr->left);
  56                 __split_expr(expr->right);
  57                 if (expr->type == EXPR_ASSIGNMENT)
  58                         __pass_to_client(expr, ASSIGNMENT_AFTER_HOOK);
  59                 return;
  60         case EXPR_DEREF:
  61                 __pass_to_client(expr, DEREF_HOOK);
  62                 __split_expr(expr->deref);
  63                 return;
  64         case EXPR_SLICE:
  65                 __split_expr(expr->base);
  66                 return;
  67         case EXPR_CAST:
  68                 __split_expr(expr->cast_expression);
  69                 return;
  70         case EXPR_SIZEOF:
  71                 /* there isn't anything to pass a client from inside a sizeof() */
  72                 return;
  73         case EXPR_CONDITIONAL:
  74         case EXPR_SELECT:
  75                 __split_whole_condition(expr->conditional);
  76                 __split_expr(expr->cond_true);
  77                 __push_true_states();
  78                 __use_false_states();
  79                 __split_expr(expr->cond_false);
  80                 __merge_true_states();
  81                 __pop_false_only_stack();
  82                 return;
  83         case EXPR_CALL:
  84                 __pass_to_client(expr, FUNCTION_CALL_HOOK);
  85                 __split_expr(expr->fn);
  86                 split_expr_list(expr->args);
  87                 __pass_to_client(expr, FUNCTION_CALL_AFTER_HOOK);
  88 #ifdef KERNEL
  89                 if (expr->fn->type == EXPR_SYMBOL &&
  90                     !strcmp(expr->fn->symbol_name->name, "panic"))
  91                         nullify_path();
  92 #endif
  93                 return;
  94         case EXPR_INITIALIZER:
  95                 split_expr_list(expr->expr_list);
  96                 return;
  97         case EXPR_IDENTIFIER:
  98                 __split_expr(expr->ident_expression);
  99                 return;
 100         case EXPR_INDEX:
 101                 __split_expr(expr->idx_expression);
 102                 return;
 103         case EXPR_POS:
 104                 __split_expr(expr->init_expr);
 105                 return;
 106         default:
 107                 return;
 108         };
 109 }
 110
 111 static int is_forever_loop(struct statement *stmt)
 112 {
 113
 114         struct expression *expr;
 115
 116         expr = stmt->iterator_pre_condition;
 117         if (!expr)
 118                 expr = stmt->iterator_post_condition;
 119         if (!expr) {
 120                 /* this is a for(;;) loop... */
 121                 return 1;
 122         }
 123
 124         if (expr->type == EXPR_VALUE && expr->value == 1) {
 125                 return 1;
 126         }
 127
 128         return 0;
 129 }
 130
 131 /*
 132  * Pre Loops are while and for loops.
 133  */
 134
 135 static void handle_pre_loop(struct statement *stmt)
 136 {
 137         int once_through; /* we go through the loop at least once */
 138
 139         split_statements(stmt->iterator_pre_statement);
 140
 141         once_through = known_condition_true(stmt->iterator_pre_condition);
 142
 143         __push_continues();
 144         __push_breaks();
 145
 146         __split_whole_condition(stmt->iterator_pre_condition);
 147
 148         split_statements(stmt->iterator_statement);
 149         split_statements(stmt->iterator_post_statement);
 150         if (is_forever_loop(stmt)) {
 151                 __pop_false_only_stack();
 152                 __pop_continues();
 153                 __pop_false_states();
 154                 __use_breaks();
 155         } else if (once_through) {
 156                 __merge_continues();
 157                 __pop_false_states();
 158                 __use_false_only_stack();
 159                 __merge_breaks();
 160         } else {
 161                 __merge_continues();
 162                 __merge_false_states();
 163                 __use_false_only_stack();
 164                 __merge_breaks();
 165         }
 166 }
 167
 168 /*
 169  * Post loops are do {} while();
 170  */
 171 static void handle_post_loop(struct statement *stmt)
 172 {
 173         __push_continues();
 174         __push_breaks();
 175         split_statements(stmt->iterator_statement);
 176
 177         __split_whole_condition(stmt->iterator_post_condition);
 178         __use_false_states();
 179
 180         if (is_forever_loop(stmt)) {
 181                 __pop_continues();
 182                 __use_breaks();
 183
 184         } else {
 185                 __merge_continues();
 186                 __merge_breaks();
 187         }
 188         __pop_false_only_stack();
 189 }
 190
 191 static void split_statements(struct statement *stmt)
 192 {
 193         if (!stmt)
 194                 return;
 195
 196         __smatch_lineno = stmt->pos.line;
 197         __pass_to_client(stmt, STMT_HOOK);
 198
 199         switch (stmt->type) {
 200         case STMT_DECLARATION:
 201                 __pass_declarations_to_client(stmt->declaration);
 202                 split_symlist(stmt->declaration);
 203                 return;
 204         case STMT_RETURN:
 205                 __pass_to_client(stmt, RETURN_HOOK);
 206                 __split_expr(stmt->ret_value);
 207                 nullify_path();
 208                 return;
 209         case STMT_EXPRESSION:
 210                 __split_expr(stmt->expression);
 211                 return;
 212         case STMT_COMPOUND: {
 213                 struct statement *s;
 214                 FOR_EACH_PTR(stmt->stmts, s) {
 215                         split_statements(s);
 216                 } END_FOR_EACH_PTR(s);
 217                 return;
 218         }
 219         case STMT_IF:
 220                 __split_whole_condition(stmt->if_conditional);
 221                 split_statements(stmt->if_true);
 222                 __push_true_states();
 223                 __use_false_states();
 224                 split_statements(stmt->if_false);
 225                 __merge_true_states();
 226                 __pop_false_only_stack();
 227                 return;
 228         case STMT_ITERATOR:
 229                 if (stmt->iterator_pre_condition)
 230                         handle_pre_loop(stmt);
 231                 else if (stmt->iterator_post_condition)
 232                         handle_post_loop(stmt);
 233                 else {
 234                         // these are for(;;) type loops.
 235                         handle_pre_loop(stmt);
 236                 }
 237                 return;
 238         case STMT_SWITCH:
 239                 __split_expr(stmt->switch_expression);
 240                 __save_switch_states();
 241                 __push_default();
 242                 __push_breaks();
 243                 nullify_path();
 244                 split_statements(stmt->switch_statement);
 245                 if (!__pop_default())
 246                         __merge_switches();
 247                 __pop_switches();
 248                 __merge_breaks();
 249                 return;
 250         case STMT_CASE:
 251                 __merge_switches();
 252                 if (!stmt->case_expression)
 253                         __set_default();
 254                 __split_expr(stmt->case_expression);
 255                 __split_expr(stmt->case_to);
 256                 split_statements(stmt->case_statement);
 257                 return;
 258         case STMT_LABEL:
 259                 if (stmt->label &&
 260                     stmt->label->type == SYM_LABEL &&
 261                     stmt->label->ident) {
 262                         __merge_gotos(stmt->label->ident->name);
 263                 }
 264                 split_statements(stmt->label_statement);
 265                 return;
 266         case STMT_GOTO:
 267                 __split_expr(stmt->goto_expression);
 268                 if (stmt->goto_label && stmt->goto_label->type == SYM_NODE) {
 269                         if (!strcmp(stmt->goto_label->ident->name, "break")) {
 270                                 __process_breaks();
 271                         } else if (!strcmp(stmt->goto_label->ident->name,
 272                                            "continue")) {
 273                                 __process_continues();
 274                         }
 275                 } else if (stmt->goto_label &&
 276                            stmt->goto_label->type == SYM_LABEL &&
 277                            stmt->goto_label->ident) {
 278                         __save_gotos(stmt->goto_label->ident->name);
 279                 }
 280                 nullify_path();
 281                 return;
 282         case STMT_NONE:
 283                 return;
 284         case STMT_ASM:
 285                 __split_expr(stmt->asm_string);
 286                 //__split_expr(stmt->asm_outputs);
 287                 //__split_expr(stmt->asm_inputs);
 288                 //__split_expr(stmt->asm_clobbers);
 289                 return;
 290         case STMT_CONTEXT:
 291                 return;
 292         case STMT_RANGE:
 293                 __split_expr(stmt->range_expression);
 294                 __split_expr(stmt->range_low);
 295                 __split_expr(stmt->range_high);
 296                 return;
 297         }
 298 }
 299
 300 static void split_expr_list(struct expression_list *expr_list)
 301 {
 302         struct expression *expr;
 303         FOR_EACH_PTR(expr_list, expr) {
 304                 __split_expr(expr);
 305         } END_FOR_EACH_PTR(expr);
 306 }
 307
 308
 309 static void split_sym(struct symbol *sym)
 310 {
 311         if (!sym)
 312                 return;
 313         if (!(sym->namespace & NS_SYMBOL))
 314                 return;
 315
 316         __pass_to_client(sym, SYM_HOOK);
 317         split_statements(sym->stmt);
 318         __split_expr(sym->array_size);
 319         split_symlist(sym->arguments);
 320         split_symlist(sym->symbol_list);
 321         split_statements(sym->inline_stmt);
 322         split_symlist(sym->inline_symbol_list);
 323         __split_expr(sym->initializer);
 324 }
 325
 326 static void split_symlist(struct symbol_list *sym_list)
 327 {
 328         struct symbol *sym;
 329
 330         FOR_EACH_PTR(sym_list, sym) {
 331                 split_sym(sym);
 332         } END_FOR_EACH_PTR(sym);
 333 }
 334
 335 static void split_functions(struct symbol_list *sym_list)
 336 {
 337         struct symbol *sym;
 338
 339         FOR_EACH_PTR(sym_list, sym) {
 340                 struct symbol *base_type;
 341                 base_type = get_base_type(sym);
 342                 if (sym->type == SYM_NODE && base_type->type == SYM_FN) {
 343                         if (base_type->stmt)
 344                                 line_func_start = base_type->stmt->pos.line;
 345                         if (sym->ident)
 346                                 cur_func = sym->ident->name;
 347                         __smatch_lineno = sym->pos.line;
 348                         SM_DEBUG("new function:  %s\n", cur_func);
 349                         __pass_to_client(sym, FUNC_DEF_HOOK);
 350                         __unnullify_path();
 351                         split_statements(base_type->stmt);
 352                         __pass_to_client(sym, END_FUNC_HOOK);
 353                         cur_func = NULL;
 354                         line_func_start = 0;
 355                         clear_all_states();
 356
 357                 } else {
 358                         __pass_to_client(sym, BASE_HOOK);
 359                 }
 360         } END_FOR_EACH_PTR(sym);
 361 }
 362
 363 void smatch (int argc, char **argv)
 364 {
 365
 366         struct string_list *filelist = NULL;
 367         struct symbol_list *sym_list;
 368
 369         if (argc < 2) {
 370                 printf("Usage:  smatch <filename.c>\n");
 371                 exit(1);
 372         }
 373         sparse_initialize(argc, argv, &filelist);
 374         FOR_EACH_PTR_NOTAG(filelist, filename) {
 375                 sym_list = __sparse(filename);
 376                 split_functions(sym_list);
 377         } END_FOR_EACH_PTR_NOTAG(filename);
 378 }