File: null-deref-offsets.c

package info (click to toggle)
llvm-toolchain-7 1%3A7.0.1-8
  • links: PTS, VCS
  • area: main
  • in suites: buster
  • size: 733,456 kB
  • sloc: cpp: 3,776,651; ansic: 633,271; asm: 350,301; python: 142,716; objc: 107,612; sh: 22,626; lisp: 11,056; perl: 7,999; pascal: 6,742; ml: 5,537; awk: 3,536; makefile: 2,557; cs: 2,027; xml: 841; ruby: 156
file content (37 lines) | stat: -rw-r--r-- 1,448 bytes parent folder | download | duplicates (28)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
// RUN: %clang_analyze_cc1 -w -triple i386-apple-darwin10 -analyzer-checker=core,debug.ExprInspection -verify %s

void clang_analyzer_eval(int);

struct S {
  int x, y;
  int z[2];
};

void testOffsets(struct S *s, int coin) {
  if (s != 0)
    return;

  // FIXME: Here we are testing the hack that computes offsets to null pointers
  // as 0 in order to find null dereferences of not-exactly-null pointers,
  // such as &(s->y) below, which is equal to 4 rather than 0 in run-time.

  // These are indeed null.
  clang_analyzer_eval(s == 0); // expected-warning{{TRUE}}
  clang_analyzer_eval(&(s->x) == 0); // expected-warning{{TRUE}}

  // FIXME: These should ideally be true.
  clang_analyzer_eval(&(s->y) == 4); // expected-warning{{FALSE}}
  clang_analyzer_eval(&(s->z[0]) == 8); // expected-warning{{FALSE}}
  clang_analyzer_eval(&(s->z[1]) == 12); // expected-warning{{FALSE}}

  // FIXME: These should ideally be false.
  clang_analyzer_eval(&(s->y) == 0); // expected-warning{{TRUE}}
  clang_analyzer_eval(&(s->z[0]) == 0); // expected-warning{{TRUE}}
  clang_analyzer_eval(&(s->z[1]) == 0); // expected-warning{{TRUE}}

  // But these should still be reported as null dereferences.
  if (coin)
    s->y = 5; // expected-warning{{Access to field 'y' results in a dereference of a null pointer (loaded from variable 's')}}
  else
    s->z[1] = 6; // expected-warning{{Array access (via field 'z') results in a null pointer dereference}}
}