smatch_helper.c

   1 /*
   2  * sparse/smatch_helper.c
   3  *
   4  * Copyright (C) 2006 Dan Carpenter.
   5  *
   6  *  Licensed under the Open Software License version 1.1
   7  *
   8  */
   9
  10 #include <stdlib.h>
  11 #include <stdio.h>
  12 #include "allocate.h"
  13 #include "smatch.h"
  14
  15 static int star_count;
  16 #define VAR_LEN 512
  17
  18
  19 char *alloc_string(char *str)
  20 {
  21         char *tmp;
  22
  23         if (!str)
  24                 return NULL;
  25         tmp = malloc(strlen(str) + 1);
  26         strcpy(tmp, str);
  27         return tmp;
  28 }
  29
  30 void free_string(char *str)
  31 {
  32         free(str);
  33 }
  34
  35 static void prepend(char *dest, const char *data, int buff_len)
  36 {
  37         int space_needed;
  38         int i;
  39
  40         space_needed = strlen(data);
  41         for (i = buff_len - space_needed - 1; i >= 0 ; i--)
  42                 dest[i + space_needed] = dest[i];
  43         for (i = 0; i < space_needed % buff_len ; i++)
  44                 dest[i] = data[i];
  45         dest[buff_len - 1] = '\0';
  46 }
  47
  48 /*
  49  * If you have "foo(a, b, 1);" then use
  50  * get_argument_from_call_expr(expr, 0) to return the expression for
  51  * a.  Yes, it does start counting from 0.
  52  */
  53 struct expression *get_argument_from_call_expr(struct expression_list *args,
  54                                                int num)
  55 {
  56         struct expression *expr;
  57         int i = 0;
  58
  59         if (!args)
  60                 return NULL;
  61
  62         FOR_EACH_PTR(args, expr) {
  63                 if (i == num)
  64                         return expr;
  65                 i++;
  66         } END_FOR_EACH_PTR(expr);
  67         return NULL;
  68 }
  69
  70 static void __get_variable_from_expr(struct symbol **sym_ptr, char *buf,
  71                                      struct expression *expr, int len,
  72                                      int *complicated)
  73 {
  74         switch(expr->type) {
  75         case EXPR_DEREF:
  76                 prepend(buf, expr->member->name, len);
  77                 if (!strcmp(show_special(expr->deref->op), "*"))
  78                         prepend(buf, "->", len);
  79                 else
  80                         prepend(buf, ".", len);
  81
  82                 //printf("debug:  %d\n", expr->deref
  83
  84                 __get_variable_from_expr(sym_ptr, buf, expr->deref,
  85                                                  len, complicated);
  86                 return;
  87         case EXPR_SYMBOL:
  88                 if (expr->symbol_name)
  89                         prepend(buf, expr->symbol_name->name, len);
  90                 if (sym_ptr) {
  91                         if (*sym_ptr)
  92                                 (*complicated)++;
  93                         *sym_ptr = expr->symbol;
  94                 }
  95                 return;
  96         case EXPR_PREOP: {
  97                 const char *tmp;
  98
  99                 if (expr->op == '*')
 100                         star_count++;
 101
 102                 __get_variable_from_expr(sym_ptr, buf, expr->unop,
 103                                                  len, complicated);
 104                 tmp = show_special(expr->op);
 105                 if (tmp[0] == '*') {
 106                         if (star_count-- >= 0) {
 107                                 prepend(buf, tmp, len);
 108                         }
 109                 } else {
 110                         prepend(buf, tmp, len);
 111                 }
 112
 113                 if (tmp[0] == '(') {
 114                         strncat(buf, ")", len);
 115                         buf[len - 1] = '\0';
 116                 }
 117
 118                 if ((!strcmp(tmp, "--")) || (!strcmp(tmp, "++")))
 119                         (*complicated)++;
 120
 121                 return;
 122         }
 123         case EXPR_POSTOP: {
 124                 const char *tmp;
 125
 126                 tmp = show_special(expr->op);
 127                 prepend(buf, tmp, len);
 128                 __get_variable_from_expr(sym_ptr, buf, expr->unop,
 129                                                  len, complicated);
 130
 131                 if ((!strcmp(tmp, "--")) || (!strcmp(tmp, "++")))
 132                         (*complicated)++;
 133
 134                 return;
 135         }
 136         case EXPR_BINOP: {
 137                 const char *tmp;
 138
 139                 prepend(buf, ")", len);
 140                 __get_variable_from_expr(NULL, buf, expr->right, len,
 141                                          complicated);
 142                 tmp = show_special(expr->op);
 143                 prepend(buf, tmp, len);
 144                 __get_variable_from_expr(sym_ptr, buf, expr->left,
 145                                                  len, complicated);
 146                 prepend(buf, "(", len);
 147                 return;
 148         }
 149         case EXPR_VALUE: {
 150                 char tmp[25];
 151
 152                 snprintf(tmp, 25, "%lld", expr->value);
 153                 prepend(buf, tmp, len);
 154                 return;
 155         }
 156         case EXPR_STRING:
 157                 prepend(buf, expr->string->data, len);
 158                 return;
 159         case EXPR_CALL: {
 160                 struct expression *tmp;
 161                 int i = 0;
 162
 163                 (*complicated)++;
 164                 prepend(buf, ")", len);
 165                 FOR_EACH_PTR_REVERSE(expr->args, tmp) {
 166                         if (i++)
 167                                 prepend(buf, ", ", len);
 168                         __get_variable_from_expr(NULL, buf, tmp, len,
 169                                                  complicated);
 170                 } END_FOR_EACH_PTR_REVERSE(tmp);
 171                 prepend(buf, "(", len);
 172                 __get_variable_from_expr(NULL, buf, expr->fn, len,
 173                                          complicated);
 174                 return;
 175         }
 176         case EXPR_CAST:
 177                 __get_variable_from_expr(sym_ptr, buf,
 178                                          expr->cast_expression, len,
 179                                          complicated);
 180                 return;
 181         case EXPR_SIZEOF: {
 182                 int size;
 183                 char tmp[25];
 184
 185                 if (expr->cast_type && get_base_type(expr->cast_type)) {
 186                         size = (get_base_type(expr->cast_type))->bit_size;
 187                         snprintf(tmp, 25, "%d", size);
 188                         prepend(buf, tmp, len);
 189                 }
 190                 return;
 191         }
 192         default:
 193                 (*complicated)++;
 194                 //printf("unknown type = %d\n", expr->type);
 195                 return;
 196         }
 197 }
 198
 199
 200 /*
 201  * This is returns a stylized "c looking" representation of the
 202  * variable name.
 203  *
 204  * It uses the same buffer every time so you have to save the result
 205  * yourself if you want to keep it.
 206  *
 207  */
 208
 209 char *get_variable_from_expr(struct expression *expr, struct symbol **sym_ptr)
 210 {
 211         static char var_name[VAR_LEN];
 212         int junk;
 213
 214         if (sym_ptr)
 215                 *sym_ptr = NULL;
 216         star_count = 0;
 217         var_name[0] = '\0';
 218
 219         if (!expr)
 220                 return NULL;
 221         __get_variable_from_expr(sym_ptr, var_name, expr, sizeof(var_name),
 222                                  &junk);
 223
 224         return var_name;
 225 }
 226
 227 /*
 228  * get_variable_from_expr_simple() only returns simple variables.
 229  * If it's a complicated variable like a->foo instead of just 'a'
 230  * then it returns NULL.
 231  */
 232
 233 char *get_variable_from_expr_simple(struct expression *expr,
 234                                     struct symbol **sym_ptr)
 235 {
 236         static char var_name[VAR_LEN];
 237         int complicated = 0;
 238
 239         if (sym_ptr)
 240                 *sym_ptr = NULL;
 241         star_count = 0;
 242         var_name[0] = '\0';
 243
 244         if (!expr)
 245                 return NULL;
 246         __get_variable_from_expr(sym_ptr, var_name, expr, sizeof(var_name),
 247                                  &complicated);
 248
 249         if (complicated) {
 250                 if (sym_ptr)
 251                         *sym_ptr = NULL;
 252                 return NULL;
 253         }
 254         return var_name;
 255 }