1// RUN: %clang_cc1 -analyze -analyzer-checker=core,alpha.core,debug.ExprInspection -analyzer-store=region -analyzer-constraints=range -verify -Wno-null-dereference -Wno-tautological-undefined-compare %s
2
3void clang_analyzer_eval(bool);
4
5typedef typeof(sizeof(int)) size_t;
6void malloc (size_t);
7
8void f1() {
9  int const &i = 3;
10  int b = i;
11
12  int *p = 0;
13
14  if (b != 3)
15    *p = 1; // no-warning
16}
17
18char* ptr();
19char& ref();
20
21// These next two tests just shouldn't crash.
22char t1 () {
23  ref() = 'c';
24  return '0';
25}
26
27// just a sanity test, the same behavior as t1()
28char t2 () {
29  *ptr() = 'c';
30  return '0';
31}
32
33// Each of the tests below is repeated with pointers as well as references.
34// This is mostly a sanity check, but then again, both should work!
35char t3 () {
36  char& r = ref();
37  r = 'c'; // no-warning
38  if (r) return r;
39  return *(char*)0; // no-warning
40}
41
42char t4 () {
43  char* p = ptr();
44  *p = 'c'; // no-warning
45  if (*p) return *p;
46  return *(char*)0; // no-warning
47}
48
49char t5 (char& r) {
50  r = 'c'; // no-warning
51  if (r) return r;
52  return *(char*)0; // no-warning
53}
54
55char t6 (char* p) {
56  *p = 'c'; // no-warning
57  if (*p) return *p;
58  return *(char*)0; // no-warning
59}
60
61
62// PR13440 / <rdar://problem/11977113>
63// Test that the array-to-pointer decay works for array references as well.
64// More generally, when we want an lvalue for a reference field, we still need
65// to do one level of load.
66namespace PR13440 {
67  typedef int T[1];
68  struct S {
69    T &x;
70
71    int *m() { return x; }
72  };
73
74  struct S2 {
75    int (&x)[1];
76
77    int *m() { return x; }
78
79    void testArrayToPointerDecayWithNonTypedValueRegion() {
80      int *p = x;
81      int *q = x;
82      clang_analyzer_eval(p[0] == q[0]); // expected-warning{{TRUE}}
83    }
84
85  };
86
87  void test() {
88    int a[1];
89    S s = { a };
90    S2 s2 = { a };
91
92    if (s.x != a) return;
93    if (s2.x != a) return;
94
95    a[0] = 42;
96    clang_analyzer_eval(s.x[0] == 42); // expected-warning{{TRUE}}
97    clang_analyzer_eval(s2.x[0] == 42); // expected-warning{{TRUE}}
98  }
99}
100
101void testNullReference() {
102  int *x = 0;
103  int &y = *x; // expected-warning{{Dereference of null pointer}}
104  y = 5;
105}
106
107void testRetroactiveNullReference(int *x) {
108  // According to the C++ standard, there is no such thing as a
109  // "null reference". So the 'if' statement ought to be dead code.
110  // However, Clang (and other compilers) don't actually check that a pointer
111  // value is non-null in the implementation of references, so it is possible
112  // to produce a supposed "null reference" at runtime. The analyzer should
113  // still warn when it can prove such errors.
114  int &y = *x;
115  if (x != 0)
116    return;
117  y = 5; // expected-warning{{Dereference of null pointer}}
118}
119
120void testReferenceAddress(int &x) {
121  clang_analyzer_eval(&x != 0); // expected-warning{{TRUE}}
122  clang_analyzer_eval(&ref() != 0); // expected-warning{{TRUE}}
123
124  struct S { int &x; };
125
126  extern S getS();
127  clang_analyzer_eval(&getS().x != 0); // expected-warning{{TRUE}}
128
129  extern S *getSP();
130  clang_analyzer_eval(&getSP()->x != 0); // expected-warning{{TRUE}}
131}
132
133
134void testFunctionPointerReturn(void *opaque) {
135  typedef int &(*RefFn)();
136
137  RefFn getRef = (RefFn)opaque;
138
139  // Don't crash writing to or reading from this reference.
140  int &x = getRef();
141  x = 42;
142  clang_analyzer_eval(x == 42); // expected-warning{{TRUE}}
143}
144
145int &testReturnNullReference() {
146  int *x = 0;
147  return *x; // expected-warning{{Returning null reference}}
148}
149
150char &refFromPointer() {
151  return *ptr();
152}
153
154void testReturnReference() {
155  clang_analyzer_eval(ptr() == 0); // expected-warning{{UNKNOWN}}
156  clang_analyzer_eval(&refFromPointer() == 0); // expected-warning{{FALSE}}
157}
158
159void intRefParam(int &r) {
160	;
161}
162
163void test(int *ptr) {
164	clang_analyzer_eval(ptr == 0); // expected-warning{{UNKNOWN}}
165
166	extern void use(int &ref);
167	use(*ptr);
168
169	clang_analyzer_eval(ptr == 0); // expected-warning{{FALSE}}
170}
171
172void testIntRefParam() {
173	int i = 0;
174	intRefParam(i); // no-warning
175}
176
177int refParam(int &byteIndex) {
178	return byteIndex;
179}
180
181void testRefParam(int *p) {
182	if (p)
183		;
184	refParam(*p); // expected-warning {{Forming reference to null pointer}}
185}
186
187int ptrRefParam(int *&byteIndex) {
188	return *byteIndex;  // expected-warning {{Dereference of null pointer}}
189}
190void testRefParam2() {
191	int *p = 0;
192	int *&rp = p;
193	ptrRefParam(rp);
194}
195
196int *maybeNull() {
197	extern bool coin();
198	static int x;
199	return coin() ? &x : 0;
200}
201
202void use(int &x) {
203	x = 1; // no-warning
204}
205
206void testSuppression() {
207	use(*maybeNull());
208}
209
210namespace rdar11212286 {
211  class B{};
212
213  B test() {
214    B *x = 0;
215    return *x; // expected-warning {{Forming reference to null pointer}}
216  }
217
218  B testif(B *x) {
219    if (x)
220      ;
221    return *x; // expected-warning {{Forming reference to null pointer}}
222  }
223
224  void idc(B *x) {
225    if (x)
226      ;
227  }
228
229  B testidc(B *x) {
230    idc(x);
231    return *x; // no-warning
232  }
233}
234
235namespace PR15694 {
236  class C {
237    bool bit : 1;
238    template <class T> void bar(const T &obj) {}
239    void foo() {
240      bar(bit); // don't crash
241    }
242  };
243}
244