null-deref-ps.c revision 65d80fd4acfe65400b7ad594042adc08e972c405 
1// RUN: clang-cc -analyze -std=gnu99 -checker-simple -verify %s &&
2// RUN: clang-cc -analyze -std=gnu99 -checker-simple -verify %s   -analyzer-constraints=range &&
3// RUN: clang-cc -analyze -std=gnu99 -checker-simple -analyzer-store=region -analyzer-purge-dead=false -verify %s &&
4// RUN: clang-cc -analyze -std=gnu99 -checker-cfref -analyzer-store=region -verify %s
5
6#include<stdint.h>
7#include <assert.h>
8
9void f1(int *p) {
10  if (p) *p = 1;
11  else *p = 0; // expected-warning{{ereference}}
12}
13
14struct foo_struct {
15  int x;
16};
17
18int f2(struct foo_struct* p) {
19
20  if (p)
21    p->x = 1;
22
23  return p->x++; // expected-warning{{Dereference of null pointer.}}
24}
25
26int f3(char* x) {
27
28  int i = 2;
29
30  if (x)
31    return x[i - 1];
32
33  return x[i+1]; // expected-warning{{Dereference of null pointer.}}
34}
35
36int f3_b(char* x) {
37
38  int i = 2;
39
40  if (x)
41    return x[i - 1];
42
43  return x[i+1]++; // expected-warning{{Dereference of null pointer.}}
44}
45
46int f4(int *p) {
47
48  uintptr_t x = (uintptr_t) p;
49
50  if (x)
51    return 1;
52
53  int *q = (int*) x;
54  return *q; // expected-warning{{Dereference of null pointer.}}
55}
56
57int f4_b() {
58  short array[2];
59  uintptr_t x = array; // expected-warning{{incompatible pointer to integer conversion initializing}}
60  short *p = x; // expected-warning{{incompatible integer to pointer conversion initializing}}
61
62  // The following branch should be infeasible.
63  if (!(p = &array[0])) {
64    p = 0;
65    *p = 1; // no-warning
66  }
67
68  if (p) {
69    *p = 5; // no-warning
70    p = 0;
71  }
72  else return; // expected-warning {{non-void function 'f4_b' should return a value}}
73
74  *p += 10; // expected-warning{{Dereference of null pointer}}
75}
76
77
78int f5() {
79
80  char *s = "hello world";
81  return s[0]; // no-warning
82}
83
84int bar(int* p, int q) __attribute__((nonnull));
85
86int f6(int *p) {
87  return !p ? bar(p, 1) // expected-warning {{Null pointer passed as an argument to a 'nonnull' parameter}}
88         : bar(p, 0);   // no-warning
89}
90
91int bar2(int* p, int q) __attribute__((nonnull(1)));
92
93int f6b(int *p) {
94  return !p ? bar2(p, 1) // expected-warning {{Null pointer passed as an argument to a 'nonnull' parameter}}
95         : bar2(p, 0);   // no-warning
96}
97
98int bar3(int*p, int q, int *r) __attribute__((nonnull(1,3)));
99
100int f6c(int *p, int *q) {
101   return !p ? bar3(q, 2, p) // expected-warning {{Null pointer passed as an argument to a 'nonnull' parameter}}
102             : bar3(p, 2, q); // no-warning
103}
104
105int* qux();
106
107int f7(int x) {
108
109  int* p = 0;
110
111  if (0 == x)
112    p = qux();
113
114  if (0 == x)
115    *p = 1; // no-warning
116
117  return x;
118}
119
120int* f7b(int *x) {
121
122  int* p = 0;
123
124  if (((void*)0) == x)
125    p = qux();
126
127  if (((void*)0) == x)
128    *p = 1; // no-warning
129
130  return x;
131}
132
133int* f7c(int *x) {
134
135  int* p = 0;
136
137  if (((void*)0) == x)
138    p = qux();
139
140  if (((void*)0) != x)
141    return x;
142
143  // If we reach here then 'p' is not null.
144  *p = 1; // no-warning
145  return x;
146}
147
148int* f7c2(int *x) {
149
150  int* p = 0;
151
152  if (((void*)0) == x)
153    p = qux();
154
155  if (((void*)0) == x)
156    return x;
157
158  *p = 1; // expected-warning{{null}}
159  return x;
160}
161
162
163int f8(int *p, int *q) {
164  if (!p)
165    if (p)
166      *p = 1; // no-warning
167
168  if (q)
169    if (!q)
170      *q = 1; // no-warning
171}
172
173int* qux();
174
175int f9(unsigned len) {
176  assert (len != 0);
177  int *p = 0;
178  unsigned i;
179
180  for (i = 0; i < len; ++i)
181   p = qux(i);
182
183  return *p++; // no-warning
184}
185
186int f9b(unsigned len) {
187  assert (len > 0);  // note use of '>'
188  int *p = 0;
189  unsigned i;
190
191  for (i = 0; i < len; ++i)
192   p = qux(i);
193
194  return *p++; // no-warning
195}
196
197int* f10(int* p, signed char x, int y) {
198  // This line tests symbolication with compound assignments where the
199  // LHS and RHS have different bitwidths.  The new symbolic value
200  // for 'x' should have a bitwidth of 8.
201  x &= y;
202
203  // This tests that our symbolication worked, and that we correctly test
204  // x against 0 (with the same bitwidth).
205  if (!x) {
206    if (!p) return; // expected-warning {{non-void function 'f10' should return a value}}
207    *p = 10;
208  }
209  else p = 0;
210
211  if (!x)
212    *p = 5; // no-warning
213
214  return p;
215}
216
217// Test case from <rdar://problem/6407949>
218void f11(unsigned i) {
219  int *x = 0;
220  if (i >= 0) {
221    // always true
222  } else {
223    *x = 42; // no-warning
224  }
225}
226
227void f11b(unsigned i) {
228  int *x = 0;
229  if (i <= ~(unsigned)0) {
230    // always true
231  } else {
232    *x = 42; // no-warning
233  }
234}
235
236// Test case for switch statements with weird case arms.
237typedef int     BOOL, *PBOOL, *LPBOOL;
238typedef long    LONG_PTR, *PLONG_PTR;
239typedef unsigned long ULONG_PTR, *PULONG_PTR;
240typedef ULONG_PTR DWORD_PTR, *PDWORD_PTR;
241typedef LONG_PTR LRESULT;
242typedef struct _F12ITEM *HF12ITEM;
243
244void f12(HF12ITEM i, char *q) {
245  char *p = 0;
246  switch ((DWORD_PTR) i) {
247  case 0 ... 10:
248    p = q;
249    break;
250  case (DWORD_PTR) ((HF12ITEM) - 65535):
251    return;
252  default:
253    return;
254  }
255
256  *p = 1; // no-warning
257}
258
259// Test handling of translating between integer "pointers" and back.
260void f13() {
261  int *x = 0;
262  if (((((int) x) << 2) + 1) >> 1) *x = 1; // no-warning
263}
264
265
266