null-deref-ps.c revision c037eac3bda3c636c961aab6377beea3242e81e4 
1// RUN: clang-cc -analyze -std=gnu99 -checker-cfref -verify %s -analyzer-constraints=basic -analyzer-store=basic &&
2// RUN: clang-cc -analyze -std=gnu99 -checker-cfref -verify %s -analyzer-constraints=basic -analyzer-store=basic-old-cast &&
3// RUN: clang-cc -analyze -std=gnu99 -checker-cfref -verify %s -analyzer-constraints=range -analyzer-store=basic &&
4// RUN: clang-cc -analyze -std=gnu99 -checker-cfref -verify %s -analyzer-constraints=range -analyzer-store=basic-old-cast &&
5// RUN: clang-cc -analyze -std=gnu99 -checker-cfref -analyzer-store=region -analyzer-constraints=range -analyzer-purge-dead=false -verify %s &&
6// RUN: clang-cc -analyze -std=gnu99 -checker-cfref -analyzer-store=region -analyzer-constraints=range -verify %s
7
8#include<stdint.h>
9#include <assert.h>
10
11void f1(int *p) {
12  if (p) *p = 1;
13  else *p = 0; // expected-warning{{ereference}}
14}
15
16struct foo_struct {
17  int x;
18};
19
20int f2(struct foo_struct* p) {
21
22  if (p)
23    p->x = 1;
24
25  return p->x++; // expected-warning{{Dereference of null pointer.}}
26}
27
28int f3(char* x) {
29
30  int i = 2;
31
32  if (x)
33    return x[i - 1];
34
35  return x[i+1]; // expected-warning{{Dereference of null pointer.}}
36}
37
38int f3_b(char* x) {
39
40  int i = 2;
41
42  if (x)
43    return x[i - 1];
44
45  return x[i+1]++; // expected-warning{{Dereference of null pointer.}}
46}
47
48int f4(int *p) {
49
50  uintptr_t x = (uintptr_t) p;
51
52  if (x)
53    return 1;
54
55  int *q = (int*) x;
56  return *q; // expected-warning{{Dereference of null pointer.}}
57}
58
59int f4_b() {
60  short array[2];
61  uintptr_t x = array; // expected-warning{{incompatible pointer to integer conversion initializing}}
62  short *p = x; // expected-warning{{incompatible integer to pointer conversion initializing}}
63
64  // The following branch should be infeasible.
65  if (!(p = &array[0])) {
66    p = 0;
67    *p = 1; // no-warning
68  }
69
70  if (p) {
71    *p = 5; // no-warning
72    p = 0;
73  }
74  else return; // expected-warning {{non-void function 'f4_b' should return a value}}
75
76  *p += 10; // expected-warning{{Dereference of null pointer}}
77}
78
79
80int f5() {
81
82  char *s = "hello world";
83  return s[0]; // no-warning
84}
85
86int bar(int* p, int q) __attribute__((nonnull));
87
88int f6(int *p) {
89  return !p ? bar(p, 1) // expected-warning {{Null pointer passed as an argument to a 'nonnull' parameter}}
90         : bar(p, 0);   // no-warning
91}
92
93int bar2(int* p, int q) __attribute__((nonnull(1)));
94
95int f6b(int *p) {
96  return !p ? bar2(p, 1) // expected-warning {{Null pointer passed as an argument to a 'nonnull' parameter}}
97         : bar2(p, 0);   // no-warning
98}
99
100int bar3(int*p, int q, int *r) __attribute__((nonnull(1,3)));
101
102int f6c(int *p, int *q) {
103   return !p ? bar3(q, 2, p) // expected-warning {{Null pointer passed as an argument to a 'nonnull' parameter}}
104             : bar3(p, 2, q); // no-warning
105}
106
107int* qux();
108
109int f7(int x) {
110
111  int* p = 0;
112
113  if (0 == x)
114    p = qux();
115
116  if (0 == x)
117    *p = 1; // no-warning
118
119  return x;
120}
121
122int* f7b(int *x) {
123
124  int* p = 0;
125
126  if (((void*)0) == x)
127    p = qux();
128
129  if (((void*)0) == x)
130    *p = 1; // no-warning
131
132  return x;
133}
134
135int* f7c(int *x) {
136
137  int* p = 0;
138
139  if (((void*)0) == x)
140    p = qux();
141
142  if (((void*)0) != x)
143    return x;
144
145  // If we reach here then 'p' is not null.
146  *p = 1; // no-warning
147  return x;
148}
149
150int* f7c2(int *x) {
151
152  int* p = 0;
153
154  if (((void*)0) == x)
155    p = qux();
156
157  if (((void*)0) == x)
158    return x;
159
160  *p = 1; // expected-warning{{null}}
161  return x;
162}
163
164
165int f8(int *p, int *q) {
166  if (!p)
167    if (p)
168      *p = 1; // no-warning
169
170  if (q)
171    if (!q)
172      *q = 1; // no-warning
173}
174
175int* qux();
176
177int f9(unsigned len) {
178  assert (len != 0);
179  int *p = 0;
180  unsigned i;
181
182  for (i = 0; i < len; ++i)
183   p = qux(i);
184
185  return *p++; // no-warning
186}
187
188int f9b(unsigned len) {
189  assert (len > 0);  // note use of '>'
190  int *p = 0;
191  unsigned i;
192
193  for (i = 0; i < len; ++i)
194   p = qux(i);
195
196  return *p++; // no-warning
197}
198
199int* f10(int* p, signed char x, int y) {
200  // This line tests symbolication with compound assignments where the
201  // LHS and RHS have different bitwidths.  The new symbolic value
202  // for 'x' should have a bitwidth of 8.
203  x &= y;
204
205  // This tests that our symbolication worked, and that we correctly test
206  // x against 0 (with the same bitwidth).
207  if (!x) {
208    if (!p) return; // expected-warning {{non-void function 'f10' should return a value}}
209    *p = 10;
210  }
211  else p = 0;
212
213  if (!x)
214    *p = 5; // no-warning
215
216  return p;
217}
218
219// Test case from <rdar://problem/6407949>
220void f11(unsigned i) {
221  int *x = 0;
222  if (i >= 0) {
223    // always true
224  } else {
225    *x = 42; // no-warning
226  }
227}
228
229void f11b(unsigned i) {
230  int *x = 0;
231  if (i <= ~(unsigned)0) {
232    // always true
233  } else {
234    *x = 42; // no-warning
235  }
236}
237
238// Test case for switch statements with weird case arms.
239typedef int     BOOL, *PBOOL, *LPBOOL;
240typedef long    LONG_PTR, *PLONG_PTR;
241typedef unsigned long ULONG_PTR, *PULONG_PTR;
242typedef ULONG_PTR DWORD_PTR, *PDWORD_PTR;
243typedef LONG_PTR LRESULT;
244typedef struct _F12ITEM *HF12ITEM;
245
246void f12(HF12ITEM i, char *q) {
247  char *p = 0;
248  switch ((DWORD_PTR) i) {
249  case 0 ... 10:
250    p = q;
251    break;
252  case (DWORD_PTR) ((HF12ITEM) - 65535):
253    return;
254  default:
255    return;
256  }
257
258  *p = 1; // no-warning
259}
260
261// Test handling of translating between integer "pointers" and back.
262void f13() {
263  int *x = 0;
264  if (((((int) x) << 2) + 1) >> 1) *x = 1; // no-warning
265}
266
267
268