clang/test/Analysis/null-deref-ps.c

   1 // RUN: %clang_analyze_cc1 -triple i386-apple-darwin10 -Wno-int-conversion -Wno-strict-prototypes -Wno-tautological-constant-compare -Wtautological-unsigned-zero-compare -analyzer-checker=core,deadcode,alpha.core -std=gnu99 -analyzer-purge=none -verify %s -Wno-error=return-type
   2 // RUN: %clang_analyze_cc1 -triple i386-apple-darwin10 -Wno-int-conversion -Wno-strict-prototypes -Wno-tautological-constant-compare -Wtautological-unsigned-zero-compare -analyzer-checker=core,deadcode,alpha.core -std=gnu99 -verify %s -Wno-error=return-type
   3
   4 typedef unsigned uintptr_t;
   5
   6 extern void __assert_fail (__const char *__assertion, __const char *__file,
   7     unsigned int __line, __const char *__function)
   8      __attribute__ ((__noreturn__));
   9
  10 #define assert(expr) \
  11   ((expr)  ? (void)(0)  : __assert_fail (#expr, __FILE__, __LINE__, __func__))
  12
  13 void f1(int *p) {
  14   if (p) *p = 1;
  15   else *p = 0; // expected-warning{{ereference}}
  16 }
  17
  18 struct foo_struct {
  19   int x;
  20 };
  21
  22 int f2(struct foo_struct* p) {
  23
  24   if (p)
  25     p->x = 1;
  26
  27   return p->x++; // expected-warning{{Access to field 'x' results in a dereference of a null pointer (loaded from variable 'p')}}
  28 }
  29
  30 int f3(char* x) {
  31
  32   int i = 2;
  33
  34   if (x)
  35     return x[i - 1];
  36
  37   return x[i+1]; // expected-warning{{Array access (from variable 'x') results in a null pointer dereference}}
  38 }
  39
  40 int f3_b(char* x) {
  41
  42   int i = 2;
  43
  44   if (x)
  45     return x[i - 1];
  46
  47   return x[i+1]++; // expected-warning{{Array access (from variable 'x') results in a null pointer dereference}}
  48 }
  49
  50 int f4(int *p) {
  51
  52   uintptr_t x = (uintptr_t) p;
  53
  54   if (x)
  55     return 1;
  56
  57   int *q = (int*) x;
  58   return *q; // expected-warning{{Dereference of null pointer (loaded from variable 'q')}}
  59 }
  60
  61 int f4_b(void) {
  62   short array[2];
  63   uintptr_t x = array;
  64   short *p = x;
  65
  66   // The following branch should be infeasible.
  67   if (!(p == &array[0])) {
  68     p = 0;
  69     *p = 1; // no-warning
  70   }
  71
  72   if (p) {
  73     *p = 5; // no-warning
  74     p = 0;
  75   }
  76   else return; // expected-warning {{non-void function 'f4_b' should return a value}}
  77
  78   *p += 10; // expected-warning{{Dereference of null pointer}}
  79   return 0;
  80 }
  81
  82 int f5(void) {
  83
  84   char *s = "hello world";
  85   return s[0]; // no-warning
  86 }
  87
  88 int bar(int* p, int q) __attribute__((nonnull));
  89
  90 int f6(int *p) {
  91   return !p ? bar(p, 1) // expected-warning {{Null pointer passed to 1st parameter expecting 'nonnull'}}
  92          : bar(p, 0);   // no-warning
  93 }
  94
  95 int bar2(int* p, int q) __attribute__((nonnull(1)));
  96
  97 int f6b(int *p) {
  98   return !p ? bar2(p, 1) // expected-warning {{Null pointer passed to 1st parameter expecting 'nonnull'}}
  99          : bar2(p, 0);   // no-warning
 100 }
 101
 102 int bar3(int*p, int q, int *r) __attribute__((nonnull(1,3)));
 103
 104 int f6c(int *p, int *q) {
 105    return !p ? bar3(q, 2, p) // expected-warning {{Null pointer passed to 3rd parameter expecting 'nonnull'}}
 106              : bar3(p, 2, q); // no-warning
 107 }
 108
 109 void f6d(int *p) {
 110   bar(p, 0);
 111   // At this point, 'p' cannot be null.
 112   if (!p) {
 113     int *q = 0;
 114     *q = 0xDEADBEEF; // no-warning
 115   }
 116 }
 117
 118 void f6e(int *p, int offset) {
 119   // PR7406 - crash from treating an UnknownVal as defined, to see if it's 0.
 120   bar((p+offset)+1, 0); // not crash
 121 }
 122
 123 int* qux();
 124
 125 int f7(int x) {
 126
 127   int* p = 0;
 128
 129   if (0 == x)
 130     p = qux();
 131
 132   if (0 == x)
 133     *p = 1; // no-warning
 134
 135   return x;
 136 }
 137
 138 int* f7b(int *x) {
 139
 140   int* p = 0;
 141
 142   if (((void*)0) == x)
 143     p = qux();
 144
 145   if (((void*)0) == x)
 146     *p = 1; // no-warning
 147
 148   return x;
 149 }
 150
 151 int* f7c(int *x) {
 152
 153   int* p = 0;
 154
 155   if (((void*)0) == x)
 156     p = qux();
 157
 158   if (((void*)0) != x)
 159     return x;
 160
 161   // If we reach here then 'p' is not null.
 162   *p = 1; // no-warning
 163   return x;
 164 }
 165
 166 int* f7c2(int *x) {
 167
 168   int* p = 0;
 169
 170   if (((void*)0) == x)
 171     p = qux();
 172
 173   if (((void*)0) == x)
 174     return x;
 175
 176   *p = 1; // expected-warning{{null}}
 177   return x;
 178 }
 179
 180
 181 void f8(int *p, int *q) {
 182   if (!p)
 183     if (p)
 184       *p = 1; // no-warning
 185
 186   if (q)
 187     if (!q)
 188       *q = 1; // no-warning
 189 }
 190
 191 int* qux();
 192
 193 int f9(unsigned len) {
 194   assert (len != 0);
 195   int *p = 0;
 196   unsigned i;
 197
 198   for (i = 0; i < len; ++i)
 199    p = qux(i);
 200
 201   return *p++; // no-warning
 202 }
 203
 204 int f9b(unsigned len) {
 205   assert (len > 0);  // note use of '>'
 206   int *p = 0;
 207   unsigned i;
 208
 209   for (i = 0; i < len; ++i)
 210    p = qux(i);
 211
 212   return *p++; // no-warning
 213 }
 214
 215 int* f10(int* p, signed char x, int y) {
 216   // This line tests symbolication with compound assignments where the
 217   // LHS and RHS have different bitwidths.  The new symbolic value
 218   // for 'x' should have a bitwidth of 8.
 219   x &= y;
 220
 221   // This tests that our symbolication worked, and that we correctly test
 222   // x against 0 (with the same bitwidth).
 223   if (!x) {
 224     if (!p) return 0;
 225     *p = 10;
 226   }
 227   else p = 0;
 228
 229   if (!x)
 230     *p = 5; // no-warning
 231
 232   return p;
 233 }
 234
 235 // Test case from <rdar://problem/6407949>
 236 void f11(unsigned i) {
 237   int *x = 0;
 238   if (i >= 0) { // expected-warning{{always true}}
 239     // always true
 240   } else {
 241     *x = 42; // no-warning
 242   }
 243 }
 244
 245 void f11b(unsigned i) {
 246   int *x = 0;
 247   if (i <= ~(unsigned)0) {
 248     // always true
 249   } else {
 250     *x = 42; // no-warning
 251   }
 252 }
 253
 254 // Test case for switch statements with weird case arms.
 255 typedef int     BOOL, *PBOOL, *LPBOOL;
 256 typedef long    LONG_PTR, *PLONG_PTR;
 257 typedef unsigned long ULONG_PTR, *PULONG_PTR;
 258 typedef ULONG_PTR DWORD_PTR, *PDWORD_PTR;
 259 typedef LONG_PTR LRESULT;
 260 typedef struct _F12ITEM *HF12ITEM;
 261
 262 void f12(HF12ITEM i, char *q) {
 263   char *p = 0;
 264   switch ((DWORD_PTR) i) {
 265   case 0 ... 10:
 266     p = q;
 267     break;
 268   case (DWORD_PTR) ((HF12ITEM) - 65535):
 269     return;
 270   default:
 271     return;
 272   }
 273
 274   *p = 1; // no-warning
 275 }
 276
 277 // Test handling of translating between integer "pointers" and back.
 278 void f13(void) {
 279   int *x = 0;
 280   if (((((int) x) << 2) + 1) >> 1) *x = 1;
 281 }
 282
 283 // PR 4759 - Attribute non-null checking by the analyzer was not correctly
 284 // handling pointer values that were undefined.
 285 void pr4759_aux(int *p) __attribute__((nonnull));
 286
 287 void pr4759(void) {
 288   int *p;
 289   pr4759_aux(p); // expected-warning{{1st function call argument is an uninitialized value}}
 290 }
 291
 292 // Relax function call arguments invalidation to be aware of const
 293 // arguments. Test with function pointers. radar://10595327
 294 void ttt(const int *nptr);
 295 void ttt2(const int *nptr);
 296 typedef void (*NoConstType)(int*);
 297 int foo10595327(int b) {
 298   void (*fp)(int *);
 299   // We use path sensitivity to get the function declaration. Even when the
 300   // function pointer is cast to non-pointer-to-const parameter type, we can
 301   // find the right function declaration.
 302   if (b > 5)
 303     fp = (NoConstType)ttt2;
 304   else
 305     fp = (NoConstType)ttt;
 306   int x = 3;
 307   int y = x + 1;
 308   int *p = 0;
 309   fp(&y);
 310   if (x == y)
 311       return *p; // no-warning
 312   return 0;
 313 }
 314
 315 #define AS_ATTRIBUTE volatile __attribute__((address_space(256)))
 316 #define _get_base() ((void * AS_ATTRIBUTE *)0)
 317 void* test_address_space_array(unsigned long slot) {
 318   return _get_base()[slot]; // no-warning
 319 }
 320 void test_address_space_condition(int AS_ATTRIBUTE *cpu_data) {
 321    if (cpu_data == 0) {
 322     *cpu_data = 3; // no-warning
 323   }
 324 }
 325 struct X { int member; };
 326 int test_address_space_member(void) {
 327   struct X AS_ATTRIBUTE *data = (struct X AS_ATTRIBUTE *)0UL;
 328   int ret;
 329   ret = data->member; // no-warning
 330   return ret;
 331 }