null-deref-ps.c revision efcfcc0e27ade4e0bb6626824f2bdc0a01bab32b 
1// RUN: clang -analyze -std=gnu99 -checker-simple -verify %s &&
2// RUN: clang -analyze -std=gnu99 -checker-simple -verify %s   -analyzer-constraints=range &&
3// RUN: clang -analyze -std=gnu99 -checker-simple -analyzer-store=region -analyzer-purge-dead=false -verify %s &&
4// RUN: clang -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;
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 f8(int *p, int *q) {
121  if (!p)
122    if (p)
123      *p = 1; // no-warning
124
125  if (q)
126    if (!q)
127      *q = 1; // no-warning
128}
129
130int* qux();
131
132int f9(unsigned len) {
133  assert (len != 0);
134  int *p = 0;
135  unsigned i;
136
137  for (i = 0; i < len; ++i)
138   p = qux(i);
139
140  return *p++; // no-warning
141}
142
143int f9b(unsigned len) {
144  assert (len > 0);  // note use of '>'
145  int *p = 0;
146  unsigned i;
147
148  for (i = 0; i < len; ++i)
149   p = qux(i);
150
151  return *p++; // no-warning
152}
153
154int* f10(int* p, signed char x, int y) {
155  // This line tests symbolication with compound assignments where the
156  // LHS and RHS have different bitwidths.  The new symbolic value
157  // for 'x' should have a bitwidth of 8.
158  x &= y;
159
160  // This tests that our symbolication worked, and that we correctly test
161  // x against 0 (with the same bitwidth).
162  if (!x) {
163    if (!p) return;
164    *p = 10;
165  }
166  else p = 0;
167
168  if (!x)
169    *p = 5; // no-warning
170
171  return p;
172}
173
174// Test case from <rdar://problem/6407949>
175void f11(unsigned i) {
176  int *x = 0;
177  if (i >= 0) {
178    // always true
179  } else {
180    *x = 42; // no-warning
181  }
182}
183
184void f11b(unsigned i) {
185  int *x = 0;
186  if (i <= ~(unsigned)0) {
187    // always true
188  } else {
189    *x = 42; // no-warning
190  }
191}
192
193// Test case for switch statements with weird case arms.
194typedef int     BOOL, *PBOOL, *LPBOOL;
195typedef long    LONG_PTR, *PLONG_PTR;
196typedef unsigned long ULONG_PTR, *PULONG_PTR;
197typedef ULONG_PTR DWORD_PTR, *PDWORD_PTR;
198typedef LONG_PTR LRESULT;
199typedef struct _F12ITEM *HF12ITEM;
200
201void f12(HF12ITEM i, char *q) {
202  char *p = 0;
203  switch ((DWORD_PTR) i) {
204  case 0 ... 10:
205    p = q;
206    break;
207  case (DWORD_PTR) ((HF12ITEM) - 65535):
208    return;
209  default:
210    return;
211  }
212
213  *p = 1; // no-warning
214}
215
216// Test handling of translating between integer "pointers" and back.
217void f13() {
218  int *x = 0;
219  if (((((int) x) << 2) + 1) >> 1) *x = 1; // no-warning
220}
221
222
223