`RULE-18-1`: Picky about how pointers are tracked, doesn't consider derefs before 1 from end, or array-to-pointer conversions

[MichaelRFairhurst]

Affected rules

• RULE-18-1
• M5-0-16

Description

The query expects that as pointers are made they are assigned to variables, and assumes that pointers into arrays always use ArrayExpr (eg x[y]). It also allows dereferencing or indexing past 1 of an array -- its OK to make a pointer to 1 past the array, but dereferencing is not defined.

Example

void example_function() {
  int x[10];

  int *p1 = &x[12]; // NON_COMPLIANT
  f(p1);

  int *p2 = x + 12; // NON_COMPLIANT[FALSE_NEGATIVE]

  f(&x[12]); // NON_COMPLIANT[FALSE_NEGATIVE]

  int *p3 = &x[10]; // COMPLIANT
  *p3; // NON_COMPLIANT[FALSE_NEGATIVE]
  x[10]; // NON_COMPLIANT[FALSE_NEGATIVE] - at least for MISRA-C
}