clang/test/Analysis/null-deref-offsets.c

   1 // RUN: %clang_analyze_cc1 -w -triple i386-apple-darwin10 -analyzer-checker=core,debug.ExprInspection -verify %s
   2
   3 void clang_analyzer_eval(int);
   4
   5 struct S {
   6   int x, y;
   7   int z[2];
   8 };
   9
  10 void testOffsets(struct S *s, int coin) {
  11   if (s != 0)
  12     return;
  13
  14   // FIXME: Here we are testing the hack that computes offsets to null pointers
  15   // as 0 in order to find null dereferences of not-exactly-null pointers,
  16   // such as &(s->y) below, which is equal to 4 rather than 0 in run-time.
  17
  18   // These are indeed null.
  19   clang_analyzer_eval(s == 0); // expected-warning{{TRUE}}
  20   clang_analyzer_eval(&(s->x) == 0); // expected-warning{{TRUE}}
  21
  22   // FIXME: These should ideally be true.
  23   clang_analyzer_eval(&(s->y) == 4); // expected-warning{{FALSE}}
  24   clang_analyzer_eval(&(s->z[0]) == 8); // expected-warning{{FALSE}}
  25   clang_analyzer_eval(&(s->z[1]) == 12); // expected-warning{{FALSE}}
  26
  27   // FIXME: These should ideally be false.
  28   clang_analyzer_eval(&(s->y) == 0); // expected-warning{{TRUE}}
  29   clang_analyzer_eval(&(s->z[0]) == 0); // expected-warning{{TRUE}}
  30   clang_analyzer_eval(&(s->z[1]) == 0); // expected-warning{{TRUE}}
  31
  32   // But these should still be reported as null dereferences.
  33   if (coin)
  34     s->y = 5; // expected-warning{{Access to field 'y' results in a dereference of a null pointer (loaded from variable 's')}}
  35   else
  36     s->z[1] = 6; // expected-warning{{Array access (via field 'z') results in a null pointer dereference}}
  37 }