clang/test/Analysis/loop-widening-notes.cpp

   1 // RUN: %clang_analyze_cc1 -analyzer-checker=core,alpha.core -analyzer-max-loop 2 -analyzer-config widen-loops=true -analyzer-output=text -verify -analyzer-config eagerly-assume=false %s
   2
   3 int *p_a;
   4 int bar();
   5 int flag_a;
   6 int test_for_bug_25609() {
   7   if (p_a == 0) // expected-note {{Assuming 'p_a' is equal to null}}
   8                 // expected-note@-1 {{Taking true branch}}
   9     bar();
  10   for (int i = 0;  // expected-note {{Loop condition is true.  Entering loop body}}
  11                    // expected-note@-1 {{Loop condition is false. Execution continues on line 16}}
  12        ++i,        // expected-note {{Value assigned to 'p_a'}}
  13        i < flag_a;
  14        ++i) {}
  15
  16   *p_a = 25609; // no-crash expected-warning {{Dereference of null pointer (loaded from variable 'p_a')}}
  17                 // expected-note@-1 {{Dereference of null pointer (loaded from variable 'p_a')}}
  18   return *p_a;
  19 }
  20
  21 int flag_b;
  22 int while_analyzer_output() {
  23   flag_b = 100;
  24   int num = 10;
  25   while (flag_b-- > 0) { // expected-note {{Loop condition is true.  Entering loop body}}
  26                          // expected-note@-1 {{Value assigned to 'num'}}
  27                          // expected-note@-2 {{Loop condition is false. Execution continues on line 30}}
  28     num = flag_b;
  29   }
  30   if (num < 0) // expected-note {{Assuming 'num' is >= 0}}
  31                // expected-note@-1 {{Taking false branch}}
  32     flag_b = 0;
  33   else if (num >= 1) // expected-note {{Assuming 'num' is < 1}}
  34                      // expected-note@-1 {{Taking false branch}}
  35     flag_b = 50;
  36   else
  37     flag_b = 100;
  38   return flag_b / num; // no-crash expected-warning {{Division by zero}}
  39                        // expected-note@-1 {{Division by zero}}
  40 }
  41
  42 int flag_c;
  43 int do_while_analyzer_output() {
  44   int num = 10;
  45   do {   // expected-note {{Loop condition is true. Execution continues on line 47}}
  46          // expected-note@-1 {{Loop condition is false.  Exiting loop}}
  47     num--;
  48   } while (flag_c-- > 0); //expected-note {{Value assigned to 'num'}}
  49   int local = 0;
  50   if (num == 0)       // expected-note {{Assuming 'num' is equal to 0}}
  51                       // expected-note@-1 {{Taking true branch}}
  52     local = 10 / num; // no-crash expected-warning {{Division by zero}}
  53                       // expected-note@-1 {{Division by zero}}
  54   return local;
  55 }
  56
  57 int flag_d;
  58 int test_for_loop() {
  59   int num = 10;
  60   for (int i = 0;    // expected-note {{Loop condition is true.  Entering loop body}}
  61                      // expected-note@-1 {{Loop condition is false. Execution continues on line 67}}
  62        new int(10),  // expected-note {{Value assigned to 'num'}}
  63        i < flag_d;
  64        ++i) {
  65     ++num;
  66   }
  67   if (num == 0) // expected-note {{Assuming 'num' is equal to 0}}
  68                 // expected-note@-1 {{Taking true branch}}
  69     flag_d += 10;
  70   return flag_d / num; // no-crash expected-warning {{Division by zero}}
  71                        // expected-note@-1 {{Division by zero}}
  72 }
  73
  74 int test_for_range_loop() {
  75   int arr[10] = {0};
  76   for(auto x : arr) { // expected-note {{Assigning value}}
  77     ++x;
  78   }
  79   if (arr[0] == 0)   // expected-note {{Assuming the condition is true}}
  80                      // expected-note@-1 {{Taking true branch}}
  81     return 1/arr[0]; // expected-warning {{Division by zero}}
  82                      // expected-note@-1 {{Division by zero}}
  83   return 0;
  84 }