Make --known-conditions an option.
[smatch.git] / smatch_flow.c
blob9d09fd2f885f49aef4570dbbea2e428afec10ac2
1 /*
2 * sparse/smatch_flow.c
4 * Copyright (C) 2006,2008 Dan Carpenter.
6 * Licensed under the Open Software License version 1.1
8 */
10 #include <stdio.h>
11 #include "token.h"
12 #include "smatch.h"
14 int __smatch_lineno = 0;
16 static char *filename;
17 static char *cur_func;
18 static int line_func_start;
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; }
25 static void split_symlist(struct symbol_list *sym_list);
26 static void split_expr_list(struct expression_list *expr_list);
28 unsigned int __get_allocations();
30 int option_assume_loops = 0;
31 int option_known_conditions = 0;
33 void __split_expr(struct expression *expr)
35 if (!expr)
36 return;
38 // printf("%d Debug expr_type %d\n", get_lineno(), expr->type);
40 __smatch_lineno = expr->pos.line;
41 __pass_to_client(expr, EXPR_HOOK);
43 switch (expr->type) {
44 case EXPR_PREOP:
45 case EXPR_POSTOP:
46 __pass_to_client(expr, OP_HOOK);
47 __split_expr(expr->unop);
48 return;
49 case EXPR_STATEMENT:
50 __split_statements(expr->statement);
51 return;
52 case EXPR_LOGICAL:
53 __split_whole_condition(expr);
54 __push_true_states();
55 __use_false_states();
56 __merge_true_states();
57 __pop_false_only_stack();
58 return;
60 return;
61 case EXPR_BINOP:
62 case EXPR_COMMA:
63 case EXPR_COMPARE:
64 case EXPR_ASSIGNMENT:
65 if (expr->type == EXPR_ASSIGNMENT)
66 __pass_to_client(expr, ASSIGNMENT_HOOK);
67 __split_expr(expr->left);
68 __split_expr(expr->right);
69 if (expr->type == EXPR_ASSIGNMENT)
70 __pass_to_client(expr, ASSIGNMENT_AFTER_HOOK);
71 return;
72 case EXPR_DEREF:
73 __pass_to_client(expr, DEREF_HOOK);
74 __split_expr(expr->deref);
75 return;
76 case EXPR_SLICE:
77 __split_expr(expr->base);
78 return;
79 case EXPR_CAST:
80 __split_expr(expr->cast_expression);
81 return;
82 case EXPR_SIZEOF:
83 /* there isn't anything to pass a client from inside a sizeof() */
84 return;
85 case EXPR_CONDITIONAL:
86 case EXPR_SELECT:
87 __split_whole_condition(expr->conditional);
88 __split_expr(expr->cond_true);
89 __push_true_states();
90 __use_false_states();
91 __split_expr(expr->cond_false);
92 __merge_true_states();
93 __pop_false_only_stack();
94 return;
95 case EXPR_CALL:
96 __pass_to_client(expr, FUNCTION_CALL_HOOK);
97 __split_expr(expr->fn);
98 split_expr_list(expr->args);
99 __pass_to_client(expr, FUNCTION_CALL_AFTER_HOOK);
100 #ifdef KERNEL
101 if (expr->fn->type == EXPR_SYMBOL &&
102 !strcmp(expr->fn->symbol_name->name, "panic"))
103 nullify_path();
104 #endif
105 return;
106 case EXPR_INITIALIZER:
107 split_expr_list(expr->expr_list);
108 return;
109 case EXPR_IDENTIFIER:
110 __split_expr(expr->ident_expression);
111 return;
112 case EXPR_INDEX:
113 __split_expr(expr->idx_expression);
114 return;
115 case EXPR_POS:
116 __split_expr(expr->init_expr);
117 return;
118 default:
119 return;
123 static int is_forever_loop(struct statement *stmt)
126 struct expression *expr;
128 expr = strip_expr(stmt->iterator_pre_condition);
129 if (!expr)
130 expr = stmt->iterator_post_condition;
131 if (!expr) {
132 /* this is a for(;;) loop... */
133 return 1;
136 if (expr->type == EXPR_VALUE && expr->value == 1) {
137 return 1;
140 return 0;
144 * Pre Loops are while and for loops.
147 static void handle_pre_loop(struct statement *stmt)
149 int once_through; /* we go through the loop at least once */
151 __split_statements(stmt->iterator_pre_statement);
153 once_through = known_condition_true(stmt->iterator_pre_condition);
154 if (option_assume_loops)
155 once_through = 1;
157 __push_continues();
158 __push_breaks();
160 __split_whole_condition(stmt->iterator_pre_condition);
162 __split_statements(stmt->iterator_statement);
163 __warn_on_silly_pre_loops();
164 if (is_forever_loop(stmt)) {
165 __pop_false_only_stack();
166 /* forever loops don't have an iterator_post_statement */
167 __pop_continues();
168 __pop_false_states();
169 __use_breaks();
170 } else if (once_through) {
171 __merge_continues();
172 __split_statements(stmt->iterator_post_statement);
173 __pop_false_states();
174 __use_false_only_stack();
175 __merge_breaks();
176 } else {
177 __merge_continues();
178 __split_statements(stmt->iterator_post_statement);
179 __merge_false_states();
180 __use_false_only_stack();
181 __merge_breaks();
186 * Post loops are do {} while();
188 static void handle_post_loop(struct statement *stmt)
190 __push_continues();
191 __push_breaks();
192 __split_statements(stmt->iterator_statement);
193 if (is_forever_loop(stmt)) {
194 __pop_continues();
195 __use_breaks();
197 } else {
198 __merge_continues();
199 __split_whole_condition(stmt->iterator_post_condition);
200 __use_false_states();
201 __merge_breaks();
203 __pop_false_only_stack();
206 static void print_unreached(struct statement *stmt)
210 * GCC insists on a return statement even where it is never
211 * reached. Also BUG() sometimes is a forever loop and
212 * sometimes not so people put code after a BUG(). There
213 * are way to many false positives.
215 #ifdef KERNEL
216 return;
217 #endif
218 if (__path_is_null()) {
219 switch(stmt->type) {
220 case STMT_COMPOUND: /* after a switch before a case stmt */
221 case STMT_CASE:
222 case STMT_LABEL:
223 case STMT_DECLARATION: /* switch(x) { int a; case foo: ... */
224 break;
225 default:
226 smatch_msg("unreachable code. %d", stmt->type);
231 void __split_statements(struct statement *stmt)
233 if (!stmt)
234 return;
236 if (__get_allocations() > MAXSMSTATES) {
237 static char *printed = NULL;
239 if (printed != cur_func)
240 smatch_msg("Function too big. Giving up.");
241 printed = cur_func;
242 return;
245 __smatch_lineno = stmt->pos.line;
246 print_unreached(stmt);
247 __pass_to_client(stmt, STMT_HOOK);
249 switch (stmt->type) {
250 case STMT_DECLARATION:
251 __pass_declarations_to_client(stmt->declaration);
252 split_symlist(stmt->declaration);
253 return;
254 case STMT_RETURN:
255 __split_expr(stmt->ret_value);
256 __pass_to_client(stmt, RETURN_HOOK);
257 nullify_path();
258 return;
259 case STMT_EXPRESSION:
260 __split_expr(stmt->expression);
261 return;
262 case STMT_COMPOUND: {
263 struct statement *s;
264 FOR_EACH_PTR(stmt->stmts, s) {
265 __split_statements(s);
266 } END_FOR_EACH_PTR(s);
267 return;
269 case STMT_IF:
270 if (option_known_conditions &&
271 known_condition_true(stmt->if_conditional)) {
272 smatch_msg("info: this condition is true.");
273 __split_statements(stmt->if_true);
274 return;
276 if (option_known_conditions &&
277 known_condition_false(stmt->if_conditional)) {
278 smatch_msg("info: this condition is false.");
279 __split_statements(stmt->if_false);
280 return;
282 __split_whole_condition(stmt->if_conditional);
283 __split_statements(stmt->if_true);
284 __push_true_states();
285 __use_false_states();
286 __split_statements(stmt->if_false);
287 __merge_true_states();
288 __pop_false_only_stack();
289 return;
290 case STMT_ITERATOR:
291 if (stmt->iterator_pre_condition)
292 handle_pre_loop(stmt);
293 else if (stmt->iterator_post_condition)
294 handle_post_loop(stmt);
295 else {
296 // these are for(;;) type loops.
297 handle_pre_loop(stmt);
299 return;
300 case STMT_SWITCH:
301 __split_expr(stmt->switch_expression);
302 __save_switch_states();
303 __push_default();
304 __push_breaks();
305 __split_statements(stmt->switch_statement);
306 if (!__pop_default())
307 __merge_switches();
308 __pop_switches();
309 __merge_breaks();
310 return;
311 case STMT_CASE:
312 __merge_switches();
313 if (!stmt->case_expression)
314 __set_default();
315 __split_expr(stmt->case_expression);
316 __split_expr(stmt->case_to);
317 __split_statements(stmt->case_statement);
318 return;
319 case STMT_LABEL:
320 if (stmt->label &&
321 stmt->label->type == SYM_LABEL &&
322 stmt->label->ident) {
323 __merge_gotos(stmt->label->ident->name);
325 __split_statements(stmt->label_statement);
326 return;
327 case STMT_GOTO:
328 __split_expr(stmt->goto_expression);
329 if (stmt->goto_label && stmt->goto_label->type == SYM_NODE) {
330 if (!strcmp(stmt->goto_label->ident->name, "break")) {
331 __process_breaks();
332 } else if (!strcmp(stmt->goto_label->ident->name,
333 "continue")) {
334 __process_continues();
336 } else if (stmt->goto_label &&
337 stmt->goto_label->type == SYM_LABEL &&
338 stmt->goto_label->ident) {
339 __save_gotos(stmt->goto_label->ident->name);
341 nullify_path();
342 return;
343 case STMT_NONE:
344 return;
345 case STMT_ASM:
346 __split_expr(stmt->asm_string);
347 //__split_expr(stmt->asm_outputs);
348 //__split_expr(stmt->asm_inputs);
349 //__split_expr(stmt->asm_clobbers);
350 return;
351 case STMT_CONTEXT:
352 return;
353 case STMT_RANGE:
354 __split_expr(stmt->range_expression);
355 __split_expr(stmt->range_low);
356 __split_expr(stmt->range_high);
357 return;
361 static void split_expr_list(struct expression_list *expr_list)
363 struct expression *expr;
364 FOR_EACH_PTR(expr_list, expr) {
365 __split_expr(expr);
366 } END_FOR_EACH_PTR(expr);
370 static void split_sym(struct symbol *sym)
372 if (!sym)
373 return;
374 if (!(sym->namespace & NS_SYMBOL))
375 return;
377 __pass_to_client(sym, SYM_HOOK);
378 __split_statements(sym->stmt);
379 __split_expr(sym->array_size);
380 split_symlist(sym->arguments);
381 split_symlist(sym->symbol_list);
382 __split_statements(sym->inline_stmt);
383 split_symlist(sym->inline_symbol_list);
384 __split_expr(sym->initializer);
387 static void split_symlist(struct symbol_list *sym_list)
389 struct symbol *sym;
391 FOR_EACH_PTR(sym_list, sym) {
392 split_sym(sym);
393 } END_FOR_EACH_PTR(sym);
396 static void split_functions(struct symbol_list *sym_list)
398 struct symbol *sym;
400 FOR_EACH_PTR(sym_list, sym) {
401 struct symbol *base_type;
402 base_type = get_base_type(sym);
403 if (sym->type == SYM_NODE && base_type->type == SYM_FN) {
404 if (base_type->stmt)
405 line_func_start = base_type->stmt->pos.line;
406 if (sym->ident)
407 cur_func = sym->ident->name;
408 __smatch_lineno = sym->pos.line;
409 SM_DEBUG("new function: %s\n", cur_func);
410 __unnullify_path();
411 __pass_to_client(sym, FUNC_DEF_HOOK);
412 __split_statements(base_type->stmt);
413 __pass_to_client(sym, END_FUNC_HOOK);
414 cur_func = NULL;
415 line_func_start = 0;
416 clear_all_states();
418 } else {
419 __pass_to_client(sym, BASE_HOOK);
421 } END_FOR_EACH_PTR(sym);
422 __pass_to_client_no_data(END_FILE_HOOK);
425 void smatch (int argc, char **argv)
428 struct string_list *filelist = NULL;
429 struct symbol_list *sym_list;
431 if (argc < 2) {
432 printf("Usage: smatch [--debug] <filename.c>\n");
433 exit(1);
435 sparse_initialize(argc, argv, &filelist);
436 FOR_EACH_PTR_NOTAG(filelist, filename) {
437 sym_list = __sparse(filename);
438 split_functions(sym_list);
439 } END_FOR_EACH_PTR_NOTAG(filename);