clang/test/Analysis/pointer-sub-notes.c

   1 // RUN: %clang_analyze_cc1 -analyzer-checker=security.PointerSub -analyzer-output=text -verify %s
   2
   3 void different_1() {
   4   int a[3]; // expected-note{{Array at the left-hand side of subtraction}}
   5   int b[3]; // expected-note{{Array at the right-hand side of subtraction}}
   6   int d = &a[2] - &b[0]; // expected-warning{{Subtraction of two pointers that do not point into the same array is undefined behavior}} \
   7                          // expected-note{{Subtraction of two pointers that do not point into the same array is undefined behavior}}
   8 }
   9
  10 void different_2() {
  11   int a[3]; // expected-note{{Array at the right-hand side of subtraction}}
  12   int b[3]; // expected-note{{Array at the left-hand side of subtraction}}
  13   int *p1 = a + 1;
  14   int *p2 = b;
  15   int d = p2 - p1; // expected-warning{{Subtraction of two pointers that do not point into the same array is undefined behavior}} \
  16                    // expected-note{{Subtraction of two pointers that do not point into the same array is undefined behavior}}
  17 }
  18
  19 int different_3() {
  20   struct {
  21     int array[5];
  22   } a, b;
  23   return &a.array[3] - &b.array[2]; // expected-warning{{Subtraction of two pointers that do not point into the same array is undefined behavior}} \
  24                                     // expected-note{{Subtraction of two pointers that do not point into the same array is undefined behavior}}
  25 }
  26
  27 int different_4() {
  28   struct {
  29     int array1[5]; // expected-note{{Array at the left-hand side of subtraction}}
  30     int array2[5]; // expected-note{{Array at the right-hand side of subtraction}}
  31   } a;
  32   return &a.array1[3] - &a.array2[4]; // expected-warning{{Subtraction of two pointers that do not point into the same array is undefined behavior}} \
  33                                       // expected-note{{Subtraction of two pointers that do not point into the same array is undefined behavior}}
  34 }
  35
  36 void different_5() {
  37   int d;
  38   static int x[10][10]; // expected-note2{{Array at the left-hand side of subtraction}}
  39   int *y1 = &(x[3][5]);
  40   char *z = ((char *) y1) + 2;
  41   int *y2 = (int *)(z - 2);
  42   int *y3 = ((int *)x) + 35; // This is offset for [3][5].
  43
  44   d = y2 - y1; // expected-warning{{Subtraction of two pointers that do not point into the same array is undefined behavior}} \
  45                // expected-note{{Subtraction of two pointers that do not point into the same array is undefined behavior}}
  46   d = y3 - y1; // expected-warning{{Subtraction of two pointers that do not point into the same array is undefined behavior}} \
  47                // expected-note{{Subtraction of two pointers that do not point into the same array is undefined behavior}}
  48   d = y3 - y2;
  49 }