check_propagate.c

   1 /*
   2  * smatch/check_propagate.c
   3  *
   4  * Copyright (C) 2010 Dan Carpenter.
   5  *
   6  * Licensed under the Open Software License version 1.1
   7  *
   8  */
   9
  10 /*
  11  * People should just return the error codes they received
  12  * instead of making up there own dumb error codes all the time.
  13  */
  14
  15 #include "smatch.h"
  16
  17 static int my_id;
  18
  19 static struct expression *last_return;
  20 static struct expression *last_func;
  21
  22 static char *get_fn_name(struct expression *expr)
  23 {
  24         if (expr->type != EXPR_CALL)
  25                 return NULL;
  26         if (expr->fn->type != EXPR_SYMBOL)
  27                 return NULL;
  28         return expr_to_var(expr->fn);
  29 }
  30
  31 static void match_call_assignment(struct expression *expr)
  32 {
  33         if (get_macro_name(expr->left->pos))
  34                 return;
  35         last_return = expr->left;
  36         last_func = expr->right;
  37 }
  38
  39 static void match_unset(struct expression *expr)
  40 {
  41         last_return = NULL;
  42 }
  43
  44 static void match_return(struct expression *ret_value)
  45 {
  46         sval_t rval;
  47         sval_t lret;
  48         char *name;
  49
  50         if (!get_value(ret_value, &rval) || rval.value >= 0)
  51                 return;
  52         if (get_implied_value(last_return, &lret))
  53                 return;
  54         if (!get_implied_max(last_return, &lret) || lret.value >= 0)
  55                 return;
  56         if (get_implied_min(last_return, &lret) && !sval_is_min(lret))
  57                 return;
  58         name = expr_to_var(last_return);
  59         sm_msg("info: why not propagate '%s' from %s() instead of %s?",
  60                 name, get_fn_name(last_func), sval_to_str(rval));
  61         free_string(name);
  62 }
  63
  64 void check_propagate(int id)
  65 {
  66         if (option_project != PROJ_KERNEL)
  67                 return;
  68
  69         my_id = id;
  70         add_hook(&match_unset, ASSIGNMENT_HOOK);
  71         add_hook(&match_call_assignment, CALL_ASSIGNMENT_HOOK);
  72         add_hook(&match_return, RETURN_HOOK);
  73 }