xref: /llvm-project/clang/test/Analysis/ptr-arith.cpp (revision 648e256e541d6421eca72df733f888787485bda8)
1 // RUN: %clang_analyze_cc1 -Wno-unused-value -std=c++14 -verify %s -triple x86_64-pc-linux-gnu \
2 // RUN:    -analyzer-checker=core,debug.ExprInspection,alpha.core.PointerArithm
3 
4 // RUN: %clang_analyze_cc1 -Wno-unused-value -std=c++14 -verify %s -triple x86_64-pc-linux-gnu \
5 // RUN:    -analyzer-config support-symbolic-integer-casts=true \
6 // RUN:    -analyzer-checker=core,debug.ExprInspection,alpha.core.PointerArithm
7 
8 template <typename T> void clang_analyzer_dump(T);
9 
10 struct X {
11   int *p;
12   int zero;
13   void foo () {
14     reset(p - 1);
15   }
16   void reset(int *in) {
17     while (in != p) // Loop must be entered.
18       zero = 1;
19   }
20 };
21 
22 int test (int *in) {
23   X littleX;
24   littleX.zero = 0;
25   littleX.p = in;
26   littleX.foo();
27   return 5/littleX.zero; // no-warning
28 }
29 
30 
31 class Base {};
32 class Derived : public Base {};
33 
34 void checkPolymorphicUse() {
35   Derived d[10];
36 
37   Base *p = d;
38   ++p; // expected-warning{{Pointer arithmetic on a pointer to base class is dangerous}}
39 }
40 
41 void checkBitCasts() {
42   long l;
43   char *p = (char*)&l;
44   p = p+2;
45 }
46 
47 void checkBasicarithmetic(int i) {
48   int t[10];
49   int *p = t;
50   ++p;
51   int a = 5;
52   p = &a;
53   ++p; // expected-warning{{Pointer arithmetic on non-array variables relies on memory layout, which is dangerous}}
54   p = p + 2; // expected-warning{{}}
55   p = 2 + p; // expected-warning{{}}
56   p += 2; // expected-warning{{}}
57   a += p[2]; // expected-warning{{}}
58   p = i*0 + p;
59   p = p + i*0;
60   p += i*0;
61 }
62 
63 void checkArithOnSymbolic(int*p) {
64   ++p;
65   p = p + 2;
66   p = 2 + p;
67   p += 2;
68   (void)p[2];
69 }
70 
71 struct S {
72   int t[10];
73 };
74 
75 void arrayInStruct() {
76   S s;
77   int * p = s.t;
78   ++p;
79   S *sp = new S;
80   p = sp->t;
81   ++p;
82   delete sp;
83 }
84 
85 void checkNew() {
86   int *p = new int;
87   p[1] = 1; // expected-warning{{}}
88 }
89 
90 void InitState(int* state) {
91     state[1] = 1; // expected-warning{{}}
92 }
93 
94 int* getArray(int size) {
95     if (size == 0)
96       return new int;
97     return new int[5];
98 }
99 
100 void checkConditionalArray() {
101     int* maybeArray = getArray(0);
102     InitState(maybeArray);
103 }
104 
105 void checkMultiDimansionalArray() {
106   int a[5][5];
107    *(*(a+1)+2) = 2;
108 }
109 
110 unsigned ptrSubtractionNoCrash(char *Begin, char *End) {
111   auto N = End - Begin;
112   if (Begin)
113     return 0;
114   return N;
115 }
116 
117 // Bug 34309
118 bool ptrAsIntegerSubtractionNoCrash(__UINTPTR_TYPE__ x, char *p) {
119   __UINTPTR_TYPE__ y = (__UINTPTR_TYPE__)p - 1;
120   return y == x;
121 }
122 
123 // Bug 34374
124 bool integerAsPtrSubtractionNoCrash(char *p, __UINTPTR_TYPE__ m) {
125   auto n = p - reinterpret_cast<char*>((__UINTPTR_TYPE__)1);
126   return n == m;
127 }
128 
129 namespace Bug_55934 {
130 struct header {
131   unsigned a : 1;
132   unsigned b : 1;
133 };
134 struct parse_t {
135   unsigned bits0 : 1;
136   unsigned bits2 : 2; // <-- header
137   unsigned bits4 : 4;
138 };
139 int parse(parse_t *p) {
140   unsigned copy = p->bits2;
141   clang_analyzer_dump(copy);
142   // expected-warning@-1 {{reg_$2<unsigned int Element{SymRegion{reg_$0<parse_t * p>},0 S64b,struct Bug_55934::parse_t}.bits2>}}
143   header *bits = (header *)&copy;
144   clang_analyzer_dump(bits->b);
145   // expected-warning@-1 {{derived_$4{reg_$2<unsigned int Element{SymRegion{reg_$0<parse_t * p>},0 S64b,struct Bug_55934::parse_t}.bits2>,Element{copy,0 S64b,struct Bug_55934::header}.b}}}
146   return bits->b; // no-warning
147 }
148 } // namespace Bug_55934
149 
150 void LValueToRValueBitCast_dumps(void *p, char (*array)[8]) {
151   clang_analyzer_dump(p);
152   clang_analyzer_dump(array);
153   // expected-warning@-2 {{&SymRegion{reg_$0<void * p>}}}
154   // expected-warning@-2 {{&SymRegion{reg_$1<char (*)[8] array>}}}
155   clang_analyzer_dump((unsigned long)p);
156   clang_analyzer_dump(__builtin_bit_cast(unsigned long, p));
157   // expected-warning@-2 {{&SymRegion{reg_$0<void * p>} [as 64 bit integer]}}
158   // expected-warning@-2 {{&SymRegion{reg_$0<void * p>} [as 64 bit integer]}}
159   clang_analyzer_dump((unsigned long)array);
160   clang_analyzer_dump(__builtin_bit_cast(unsigned long, array));
161   // expected-warning@-2 {{&SymRegion{reg_$1<char (*)[8] array>} [as 64 bit integer]}}
162   // expected-warning@-2 {{&SymRegion{reg_$1<char (*)[8] array>} [as 64 bit integer]}}
163 }
164 
165 unsigned long ptr_arithmetic(void *p) {
166   return __builtin_bit_cast(unsigned long, p) + 1; // no-crash
167 }
168