null-deref-ps.c revision d427023c334fe03105d9359711a3df4d6f23b344 
1// RUN: clang -analyze -std=gnu99 -checker-simple -verify %s &&
2// RUN: clang -analyze -std=gnu99 -checker-simple -analyzer-store-region -analyzer-purge-dead=false -verify %s
3
4#include<stdint.h>
5#include <assert.h>
6
7void f1(int *p) {
8  if (p) *p = 1;
9  else *p = 0; // expected-warning{{ereference}}
10}
11
12struct foo_struct {
13  int x;
14};
15
16int f2(struct foo_struct* p) {
17
18  if (p)
19    p->x = 1;
20
21  return p->x++; // expected-warning{{Dereference of null pointer.}}
22}
23
24int f3(char* x) {
25
26  int i = 2;
27
28  if (x)
29    return x[i - 1];
30
31  return x[i+1]; // expected-warning{{Dereference of null pointer.}}
32}
33
34int f3_b(char* x) {
35
36  int i = 2;
37
38  if (x)
39    return x[i - 1];
40
41  return x[i+1]++; // expected-warning{{Dereference of null pointer.}}
42}
43
44int f4(int *p) {
45
46  uintptr_t x = (uintptr_t) p;
47
48  if (x)
49    return 1;
50
51  int *q = (int*) x;
52  return *q; // expected-warning{{Dereference of null pointer.}}
53}
54
55int f4_b() {
56  short array[2];
57  uintptr_t x = array; // expected-warning{{incompatible pointer to integer conversion initializing}}
58  short *p = x; // expected-warning{{incompatible integer to pointer conversion initializing}}
59
60  // The following branch should be infeasible.
61  if (!(p = &array[0])) {
62    p = 0;
63    *p = 1; // no-warning
64  }
65
66  if (p) {
67    *p = 5; // no-warning
68    p = 0;
69  }
70  else return;
71
72  *p += 10; // expected-warning{{Dereference of null pointer}}
73}
74
75
76int f5() {
77
78  char *s = "hello world";
79  return s[0]; // no-warning
80}
81
82int bar(int* p, int q) __attribute__((nonnull));
83
84int f6(int *p) {
85  return !p ? bar(p, 1) // expected-warning {{Null pointer passed as an argument to a 'nonnull' parameter}}
86         : bar(p, 0);   // no-warning
87}
88
89int bar2(int* p, int q) __attribute__((nonnull(1)));
90
91int f6b(int *p) {
92  return !p ? bar2(p, 1) // expected-warning {{Null pointer passed as an argument to a 'nonnull' parameter}}
93         : bar2(p, 0);   // no-warning
94}
95
96int bar3(int*p, int q, int *r) __attribute__((nonnull(1,3)));
97
98int f6c(int *p, int *q) {
99   return !p ? bar3(q, 2, p) // expected-warning {{Null pointer passed as an argument to a 'nonnull' parameter}}
100             : bar3(p, 2, q); // no-warning
101}
102
103int* qux();
104
105int f7(int x) {
106
107  int* p = 0;
108
109  if (0 == x)
110    p = qux();
111
112  if (0 == x)
113    *p = 1; // no-warning
114
115  return x;
116}
117
118int f8(int *p, int *q) {
119  if (!p)
120    if (p)
121      *p = 1; // no-warning
122
123  if (q)
124    if (!q)
125      *q = 1; // no-warning
126}
127
128int* qux();
129
130int f9(unsigned len) {
131  assert (len != 0);
132  int *p = 0;
133  unsigned i;
134
135  for (i = 0; i < len; ++i)
136   p = qux(i);
137
138  return *p++; // no-warning
139}
140
141int f9b(unsigned len) {
142  assert (len > 0);  // note use of '>'
143  int *p = 0;
144  unsigned i;
145
146  for (i = 0; i < len; ++i)
147   p = qux(i);
148
149  return *p++; // no-warning
150}
151
152int* f10(int* p, signed char x, int y) {
153  // This line tests symbolication with compound assignments where the
154  // LHS and RHS have different bitwidths.  The new symbolic value
155  // for 'x' should have a bitwidth of 8.
156  x &= y;
157
158  // This tests that our symbolication worked, and that we correctly test
159  // x against 0 (with the same bitwidth).
160  if (!x) {
161    if (!p) return;
162    *p = 10;
163  }
164  else p = 0;
165
166  if (!x)
167    *p = 5; // no-warning
168
169  return p;
170}
171
172// Test case from <rdar://problem/6407949>
173void f11(unsigned i) {
174  int *x = 0;
175  if (i >= 0) {
176    // always true
177  } else {
178    *x = 42; // no-warning
179  }
180}
181
182void f11b(unsigned i) {
183  int *x = 0;
184  if (i <= ~(unsigned)0) {
185    // always true
186  } else {
187    *x = 42; // no-warning
188  }
189}
190
191// Test case for switch statements with weird case arms.
192typedef int     BOOL, *PBOOL, *LPBOOL;
193typedef long    LONG_PTR, *PLONG_PTR;
194typedef unsigned long ULONG_PTR, *PULONG_PTR;
195typedef ULONG_PTR DWORD_PTR, *PDWORD_PTR;
196typedef LONG_PTR LRESULT;
197typedef struct _F12ITEM *HF12ITEM;
198
199void f12(HF12ITEM i, char *q) {
200  char *p = 0;
201  switch ((DWORD_PTR) i) {
202  case 0 ... 10:
203    p = q;
204    break;
205  case (DWORD_PTR) ((HF12ITEM) - 65535):
206    return;
207  default:
208    return;
209  }
210
211  *p = 1; // no-warning
212}
213
214