ptr-arith.c revision 651f13cea278ec967336033dd032faef0e9fc2ec 
1// RUN: %clang_cc1 -analyze -analyzer-checker=alpha.core.FixedAddr,alpha.core.PointerArithm,alpha.core.PointerSub,debug.ExprInspection -analyzer-store=region -verify -triple x86_64-apple-darwin9 -Wno-tautological-pointer-compare %s
2// RUN: %clang_cc1 -analyze -analyzer-checker=alpha.core.FixedAddr,alpha.core.PointerArithm,alpha.core.PointerSub,debug.ExprInspection -analyzer-store=region -verify -triple i686-apple-darwin9 -Wno-tautological-pointer-compare %s
3
4void clang_analyzer_eval(int);
5
6void f1() {
7  int a[10];
8  int *p = a;
9  ++p;
10}
11
12char* foo();
13
14void f2() {
15  char *p = foo();
16  ++p;
17}
18
19// This test case checks if we get the right rvalue type of a TypedViewRegion.
20// The ElementRegion's type depends on the array region's rvalue type. If it was
21// a pointer type, we would get a loc::SymbolVal for '*p'.
22void* memchr();
23static int
24domain_port (const char *domain_b, const char *domain_e,
25             const char **domain_e_ptr)
26{
27  int port = 0;
28
29  const char *p;
30  const char *colon = memchr (domain_b, ':', domain_e - domain_b);
31
32  for (p = colon + 1; p < domain_e ; p++)
33    port = 10 * port + (*p - '0');
34  return port;
35}
36
37void f3() {
38  int x, y;
39  int d = &y - &x; // expected-warning{{Subtraction of two pointers that do not point to the same memory chunk may cause incorrect result}}
40
41  int a[10];
42  int *p = &a[2];
43  int *q = &a[8];
44  d = q-p; // no-warning
45}
46
47void f4() {
48  int *p;
49  p = (int*) 0x10000; // expected-warning{{Using a fixed address is not portable because that address will probably not be valid in all environments or platforms}}
50}
51
52void f5() {
53  int x, y;
54  int *p;
55  p = &x + 1;  // expected-warning{{Pointer arithmetic done on non-array variables means reliance on memory layout, which is dangerous}}
56
57  int a[10];
58  p = a + 1; // no-warning
59}
60
61// Allow arithmetic on different symbolic regions.
62void f6(int *p, int *q) {
63  int d = q - p; // no-warning
64}
65
66void null_operand(int *a) {
67start:
68  // LHS is a label, RHS is NULL
69  clang_analyzer_eval(&&start != 0); // expected-warning{{TRUE}}
70  clang_analyzer_eval(&&start >= 0); // expected-warning{{TRUE}}
71  clang_analyzer_eval(&&start > 0); // expected-warning{{TRUE}}
72  clang_analyzer_eval((&&start - 0) != 0); // expected-warning{{TRUE}}
73
74  // LHS is a non-symbolic value, RHS is NULL
75  clang_analyzer_eval(&a != 0); // expected-warning{{TRUE}}
76  clang_analyzer_eval(&a >= 0); // expected-warning{{TRUE}}
77  clang_analyzer_eval(&a > 0); // expected-warning{{TRUE}}
78  clang_analyzer_eval((&a - 0) != 0); // expected-warning{{TRUE}} expected-warning{{Pointer arithmetic done on non-array variables}}
79
80  // LHS is NULL, RHS is non-symbolic
81  // The same code is used for labels and non-symbolic values.
82  clang_analyzer_eval(0 != &a); // expected-warning{{TRUE}}
83  clang_analyzer_eval(0 <= &a); // expected-warning{{TRUE}}
84  clang_analyzer_eval(0 < &a); // expected-warning{{TRUE}}
85
86  // LHS is a symbolic value, RHS is NULL
87  clang_analyzer_eval(a != 0); // expected-warning{{UNKNOWN}}
88  clang_analyzer_eval(a >= 0); // expected-warning{{TRUE}}
89  clang_analyzer_eval(a <= 0); // expected-warning{{UNKNOWN}}
90  clang_analyzer_eval((a - 0) != 0); // expected-warning{{UNKNOWN}}
91
92  // LHS is NULL, RHS is a symbolic value
93  clang_analyzer_eval(0 != a); // expected-warning{{UNKNOWN}}
94  clang_analyzer_eval(0 <= a); // expected-warning{{TRUE}}
95  clang_analyzer_eval(0 < a); // expected-warning{{UNKNOWN}}
96}
97
98void const_locs() {
99  char *a = (char*)0x1000;
100  char *b = (char*)0x1100;
101start:
102  clang_analyzer_eval(a != b); // expected-warning{{TRUE}}
103  clang_analyzer_eval(a < b); // expected-warning{{TRUE}}
104  clang_analyzer_eval(a <= b); // expected-warning{{TRUE}}
105  clang_analyzer_eval((b-a) == 0x100); // expected-warning{{TRUE}}
106
107  clang_analyzer_eval(&&start == a); // expected-warning{{UNKNOWN}}
108  clang_analyzer_eval(a == &&start); // expected-warning{{UNKNOWN}}
109  clang_analyzer_eval(&a == (char**)a); // expected-warning{{UNKNOWN}}
110  clang_analyzer_eval((char**)a == &a); // expected-warning{{UNKNOWN}}
111}
112
113void array_matching_types() {
114  int array[10];
115  int *a = &array[2];
116  int *b = &array[5];
117
118  clang_analyzer_eval(a != b); // expected-warning{{TRUE}}
119  clang_analyzer_eval(a < b); // expected-warning{{TRUE}}
120  clang_analyzer_eval(a <= b); // expected-warning{{TRUE}}
121  clang_analyzer_eval((b-a) != 0); // expected-warning{{TRUE}}
122}
123
124// This takes a different code path than array_matching_types()
125void array_different_types() {
126  int array[10];
127  int *a = &array[2];
128  char *b = (char*)&array[5];
129
130  clang_analyzer_eval(a != b); // expected-warning{{TRUE}} expected-warning{{comparison of distinct pointer types}}
131  clang_analyzer_eval(a < b); // expected-warning{{TRUE}} expected-warning{{comparison of distinct pointer types}}
132  clang_analyzer_eval(a <= b); // expected-warning{{TRUE}} expected-warning{{comparison of distinct pointer types}}
133}
134
135struct test { int x; int y; };
136void struct_fields() {
137  struct test a, b;
138
139  clang_analyzer_eval(&a.x != &a.y); // expected-warning{{TRUE}}
140  clang_analyzer_eval(&a.x < &a.y); // expected-warning{{TRUE}}
141  clang_analyzer_eval(&a.x <= &a.y); // expected-warning{{TRUE}}
142
143  clang_analyzer_eval(&a.x != &b.x); // expected-warning{{TRUE}}
144  clang_analyzer_eval(&a.x > &b.x); // expected-warning{{UNKNOWN}}
145  clang_analyzer_eval(&a.x >= &b.x); // expected-warning{{UNKNOWN}}
146}
147
148void mixed_region_types() {
149  struct test s;
150  int array[2];
151  void *a = &array, *b = &s;
152
153  clang_analyzer_eval(&a != &b); // expected-warning{{TRUE}}
154  clang_analyzer_eval(&a > &b); // expected-warning{{UNKNOWN}}
155  clang_analyzer_eval(&a >= &b); // expected-warning{{UNKNOWN}}
156}
157
158void symbolic_region(int *p) {
159  int a;
160
161  clang_analyzer_eval(&a != p); // expected-warning{{TRUE}}
162  clang_analyzer_eval(&a > p); // expected-warning{{UNKNOWN}}
163  clang_analyzer_eval(&a >= p); // expected-warning{{UNKNOWN}}
164}
165
166void PR7527 (int *p) {
167  if (((int) p) & 1) // not crash
168    return;
169}
170
171void use_symbols(int *lhs, int *rhs) {
172  clang_analyzer_eval(lhs < rhs); // expected-warning{{UNKNOWN}}
173  if (lhs < rhs)
174    return;
175  clang_analyzer_eval(lhs < rhs); // expected-warning{{FALSE}}
176
177  clang_analyzer_eval(lhs - rhs); // expected-warning{{UNKNOWN}}
178  if ((lhs - rhs) != 5)
179    return;
180  clang_analyzer_eval((lhs - rhs) == 5); // expected-warning{{TRUE}}
181}
182
183void equal_implies_zero(int *lhs, int *rhs) {
184  clang_analyzer_eval(lhs == rhs); // expected-warning{{UNKNOWN}}
185  if (lhs == rhs) {
186    clang_analyzer_eval(lhs != rhs); // expected-warning{{FALSE}}
187    clang_analyzer_eval((rhs - lhs) == 0); // expected-warning{{TRUE}}
188    return;
189  }
190  clang_analyzer_eval(lhs == rhs); // expected-warning{{FALSE}}
191  clang_analyzer_eval(lhs != rhs); // expected-warning{{TRUE}}
192  clang_analyzer_eval((rhs - lhs) == 0); // expected-warning{{FALSE}}
193}
194
195void zero_implies_equal(int *lhs, int *rhs) {
196  clang_analyzer_eval((rhs - lhs) == 0); // expected-warning{{UNKNOWN}}
197  if ((rhs - lhs) == 0) {
198    clang_analyzer_eval(lhs != rhs); // expected-warning{{FALSE}}
199    clang_analyzer_eval(lhs == rhs); // expected-warning{{TRUE}}
200    return;
201  }
202  clang_analyzer_eval((rhs - lhs) == 0); // expected-warning{{FALSE}}
203  clang_analyzer_eval(lhs == rhs); // expected-warning{{FALSE}}
204  clang_analyzer_eval(lhs != rhs); // expected-warning{{TRUE}}
205}
206
207void comparisons_imply_size(int *lhs, int *rhs) {
208  clang_analyzer_eval(lhs <= rhs); // expected-warning{{UNKNOWN}}
209
210  if (lhs > rhs) {
211    clang_analyzer_eval((rhs - lhs) == 0); // expected-warning{{FALSE}}
212    return;
213  }
214
215  clang_analyzer_eval(lhs <= rhs); // expected-warning{{TRUE}}
216  clang_analyzer_eval((rhs - lhs) >= 0); // expected-warning{{TRUE}}
217  clang_analyzer_eval((rhs - lhs) > 0); // expected-warning{{UNKNOWN}}
218
219  if (lhs >= rhs) {
220    clang_analyzer_eval((rhs - lhs) == 0); // expected-warning{{TRUE}}
221    return;
222  }
223
224  clang_analyzer_eval(lhs == rhs); // expected-warning{{FALSE}}
225  clang_analyzer_eval(lhs < rhs); // expected-warning{{TRUE}}
226  clang_analyzer_eval((rhs - lhs) > 0); // expected-warning{{TRUE}}
227}
228
229void size_implies_comparison(int *lhs, int *rhs) {
230  clang_analyzer_eval(lhs <= rhs); // expected-warning{{UNKNOWN}}
231
232  if ((rhs - lhs) < 0) {
233    clang_analyzer_eval(lhs == rhs); // expected-warning{{FALSE}}
234    return;
235  }
236
237  clang_analyzer_eval(lhs <= rhs); // expected-warning{{TRUE}}
238  clang_analyzer_eval((rhs - lhs) >= 0); // expected-warning{{TRUE}}
239  clang_analyzer_eval((rhs - lhs) > 0); // expected-warning{{UNKNOWN}}
240
241  if ((rhs - lhs) <= 0) {
242    clang_analyzer_eval(lhs == rhs); // expected-warning{{TRUE}}
243    return;
244  }
245
246  clang_analyzer_eval(lhs == rhs); // expected-warning{{FALSE}}
247  clang_analyzer_eval(lhs < rhs); // expected-warning{{TRUE}}
248  clang_analyzer_eval((rhs - lhs) > 0); // expected-warning{{TRUE}}
249}
250
251//-------------------------------
252// False positives
253//-------------------------------
254
255void zero_implies_reversed_equal(int *lhs, int *rhs) {
256  clang_analyzer_eval((rhs - lhs) == 0); // expected-warning{{UNKNOWN}}
257  if ((rhs - lhs) == 0) {
258    // FIXME: Should be FALSE.
259    clang_analyzer_eval(rhs != lhs); // expected-warning{{UNKNOWN}}
260    // FIXME: Should be TRUE.
261    clang_analyzer_eval(rhs == lhs); // expected-warning{{UNKNOWN}}
262    return;
263  }
264  clang_analyzer_eval((rhs - lhs) == 0); // expected-warning{{FALSE}}
265  // FIXME: Should be FALSE.
266  clang_analyzer_eval(rhs == lhs); // expected-warning{{UNKNOWN}}
267  // FIXME: Should be TRUE.
268  clang_analyzer_eval(rhs != lhs); // expected-warning{{UNKNOWN}}
269}
270
271void canonical_equal(int *lhs, int *rhs) {
272  clang_analyzer_eval(lhs == rhs); // expected-warning{{UNKNOWN}}
273  if (lhs == rhs) {
274    // FIXME: Should be TRUE.
275    clang_analyzer_eval(rhs == lhs); // expected-warning{{UNKNOWN}}
276    return;
277  }
278  clang_analyzer_eval(lhs == rhs); // expected-warning{{FALSE}}
279
280  // FIXME: Should be FALSE.
281  clang_analyzer_eval(rhs == lhs); // expected-warning{{UNKNOWN}}
282}
283
284void compare_element_region_and_base(int *p) {
285  int *q = p - 1;
286  clang_analyzer_eval(p == q); // expected-warning{{FALSE}}
287}
288
289struct Point {
290  int x;
291  int y;
292};
293void symbolicFieldRegion(struct Point *points, int i, int j) {
294  clang_analyzer_eval(&points[i].x == &points[j].x);// expected-warning{{UNKNOWN}}
295  clang_analyzer_eval(&points[i].x == &points[i].y);// expected-warning{{FALSE}}
296  clang_analyzer_eval(&points[i].x < &points[i].y);// expected-warning{{TRUE}}
297}
298
299