clang/test/Analysis/diagnostics/track_subexpressions.cpp

   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