1 // RUN: %clang_analyze_cc1 -x c++ -analyzer-checker=core -analyzer-output=text -verify %s
2 
3 typedef unsigned char uint8_t;
4 
5 #define UINT8_MAX 255
6 #define TCP_MAXWIN 65535
7 
8 uint8_t get_uint8_max() {
9   uint8_t rcvscale = UINT8_MAX; // expected-note{{'rcvscale' initialized to 255}}
10   return rcvscale; // expected-note{{Returning the value 255 (loaded from 'rcvscale')}}
11 }
12 
13 void shift_by_undefined_value() {
14   uint8_t shift_amount = get_uint8_max(); // expected-note{{'shift_amount' initialized to 255}}
15                                 // expected-note@-1{{Calling 'get_uint8_max'}}
16                                 // expected-note@-2{{Returning from 'get_uint8_max'}}
17   (void)(TCP_MAXWIN << shift_amount); // expected-warning{{The result of the left shift is undefined due to shifting by '255', which is greater or equal to the width of type 'int'}}
18                                       // expected-note@-1{{The result of the left shift is undefined due to shifting by '255', which is greater or equal to the width of type 'int'}}
19 }
20 
21 namespace array_index_tracking {
22 void consume(int);
23 
24 int getIndex(int x) {
25   int a;
26   if (x > 0) // expected-note {{Assuming 'x' is > 0}}
27              // expected-note@-1 {{Taking true branch}}
28     a = 3; // expected-note {{The value 3 is assigned to 'a'}}
29   else
30     a = 2;
31   return a; // expected-note {{Returning the value 3 (loaded from 'a')}}
32 }
33 
34 int getInt();
35 
36 void testArrayIndexTracking() {
37   int arr[10];
38 
39   for (int i = 0; i < 3; ++i)
40     // expected-note@-1 3{{Loop condition is true.  Entering loop body}}
41     // expected-note@-2 {{Loop condition is false. Execution continues on line 43}}
42     arr[i] = 0;
43   int x = getInt();
44   int n = getIndex(x); // expected-note {{Calling 'getIndex'}}
45                        // expected-note@-1 {{Returning from 'getIndex'}}
46                        // expected-note@-2 {{'n' initialized to 3}}
47   consume(arr[n]);
48   // expected-note@-1 {{1st function call argument is an uninitialized value}}
49   // expected-warning@-2{{1st function call argument is an uninitialized value}}
50 }
51 } // end of namespace array_index_tracking
52 
53 namespace multi_array_index_tracking {
54 void consume(int);
55 
56 int getIndex(int x) {
57   int a;
58   if (x > 0) // expected-note {{Assuming 'x' is > 0}}
59              // expected-note@-1 {{Taking true branch}}
60     a = 3; // expected-note {{The value 3 is assigned to 'a'}}
61   else
62     a = 2;
63   return a; // expected-note {{Returning the value 3 (loaded from 'a')}}
64 }
65 
66 int getInt();
67 
68 void testArrayIndexTracking() {
69   int arr[2][10];
70 
71   for (int i = 0; i < 3; ++i)
72     // expected-note@-1 3{{Loop condition is true.  Entering loop body}}
73     // expected-note@-2 {{Loop condition is false. Execution continues on line 75}}
74     arr[1][i] = 0;
75   int x = getInt();
76   int n = getIndex(x); // expected-note {{Calling 'getIndex'}}
77                        // expected-note@-1 {{Returning from 'getIndex'}}
78                        // expected-note@-2 {{'n' initialized to 3}}
79   consume(arr[1][n]);
80   // expected-note@-1 {{1st function call argument is an uninitialized value}}
81   // expected-warning@-2{{1st function call argument is an uninitialized value}}
82 }
83 } // end of namespace mulit_array_index_tracking
84