smatch_unknown_value.c

   1 /*
   2  * Copyright (C) 2014 Oracle.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License
   6  * as published by the Free Software Foundation; either version 2
   7  * of the License, or (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, see http://www.gnu.org/copyleft/gpl.txt
  16  */
  17
  18 /*
  19  * The situation here is that we often need to fake an assignment but we don't
  20  * know anything about the right hand side of the assignment.  We use a fake
  21  * function call of &llong_ctype.  The reason for using a function call instead
  22  * of a value is so we don't start storing the equivalence.
  23  *
  24  */
  25
  26 #include "smatch.h"
  27
  28 struct ident fake_assign = {
  29         .len = sizeof("fake assign"),
  30         .name = "fake assign",
  31 };
  32
  33 static struct symbol fake_fn_symbol = {
  34         .type = SYM_FN,
  35         .ident = &fake_assign,
  36 };
  37
  38 static struct symbol fake_node_symbol = {
  39         .type = SYM_NODE,
  40         .ident = &fake_assign,
  41 };
  42
  43 static struct expression fake_fn_expr = {
  44         .type = EXPR_SYMBOL,
  45         .ctype = &llong_ctype,
  46 };
  47
  48 static struct expression fake_call = {
  49         .type = EXPR_CALL,
  50         .ctype = &llong_ctype,
  51 };
  52
  53 static void __attribute__((constructor)) initialize_local_variables(void)
  54 {
  55         fake_fn_symbol.ctype.base_type = &llong_ctype;
  56         fake_node_symbol.ctype.base_type = &fake_fn_symbol;
  57         fake_fn_expr.symbol = &fake_node_symbol;
  58         fake_fn_expr.symbol_name = &fake_assign;
  59         fake_call.fn = &fake_fn_expr;
  60 }
  61
  62 struct expression *unknown_value_expression(struct expression *expr)
  63 {
  64         fake_fn_expr.parent = 0;
  65         fake_call.parent = 0;
  66         return &fake_call;
  67 }
  68
  69 int is_fake_call(struct expression *expr)
  70 {
  71         return expr == &fake_call;
  72 }