clang/test/Analysis/diagnostics/macro-null-return-suppression.cpp

   1 // RUN: %clang_analyze_cc1 -x c -analyzer-checker=core -analyzer-output=text -verify %s
   2
   3 #define NULL 0
   4
   5 int test_noparammacro(void) {
   6   int *x = NULL; // expected-note{{'x' initialized to a null pointer value}}
   7   return *x; // expected-warning{{Dereference of null pointer (loaded from variable 'x')}}
   8              // expected-note@-1{{Dereference of null pointer (loaded from variable 'x')}}
   9 }
  10
  11 #define DYN_CAST(X) (X ? (char*)X : 0)
  12 #define GENERATE_NUMBER(X) (0)
  13
  14 char test_assignment(int *param) {
  15   char *param2;
  16   param2 = DYN_CAST(param);
  17   return *param2;
  18 }
  19
  20 char test_declaration(int *param) {
  21   char *param2 = DYN_CAST(param);
  22   return *param2;
  23 }
  24
  25 int coin(void);
  26
  27 int test_multi_decl(int *paramA, int *paramB) {
  28   char *param1 = DYN_CAST(paramA), *param2 = DYN_CAST(paramB);
  29   if (coin())
  30     return *param1;
  31   return *param2;
  32 }
  33
  34 int testDivision(int a) {
  35   int divider = GENERATE_NUMBER(2); // expected-note{{'divider' initialized to 0}}
  36   return 1/divider; // expected-warning{{Division by zero}}
  37                     // expected-note@-1{{Division by zero}}
  38 }
  39
  40 // Warning should not be suppressed if it happens in the same macro.
  41 #define DEREF_IN_MACRO(X) int fn(void) {int *p = 0; return *p; }
  42
  43 DEREF_IN_MACRO(0) // expected-warning{{Dereference of null pointer}}
  44                   // expected-note@-1{{'p' initialized to a null}}
  45                   // expected-note@-2{{Dereference of null pointer}}
  46
  47 // Warning should not be suppressed if the null returned by the macro
  48 // is not related to the warning.
  49 #define RETURN_NULL() (0)
  50 extern int* returnFreshPointer(void);
  51 int noSuppressMacroUnrelated(void) {
  52   int *x = RETURN_NULL();
  53   x = returnFreshPointer();  // expected-note{{Value assigned to 'x'}}
  54   if (x) {} // expected-note{{Taking false branch}}
  55             // expected-note@-1{{Assuming 'x' is null}}
  56   return *x; // expected-warning{{Dereference of null pointer}}
  57              // expected-note@-1{{Dereference}}
  58 }
  59
  60 // Value haven't changed by the assignment, but the null pointer
  61 // did not come from the macro.
  62 int noSuppressMacroUnrelatedOtherReason(void) {
  63   int *x = RETURN_NULL();
  64   x = returnFreshPointer();
  65   x = 0; // expected-note{{Null pointer value stored to 'x'}}
  66   return *x; // expected-warning{{Dereference of null pointer}}
  67              // expected-note@-1{{Dereference}}
  68 }