Merge pull request #490 from github/lcartey/a4-7-1-no-pointers

A4-7-1: Exclude pointer increment/decrement expressions

Author: rvermeulen

change_notes/2024-01-17-a4-7-1-exclude-pointers.md

@@ -0,0 +1 @@
+ * `A4-7-1` - exclude pointer increment and decrement operators from this rule.

cpp/autosar/test/rules/A4-7-1/test.cpp

@@ -62,4 +62,10 @@ void test_loop_bound_bad(unsigned int n) {
        i++) { // NON_COMPLIANT - crement will overflow before loop bound is
               // reached
   }
+}
+
+void test_pointer() {
+  int *p = nullptr;
+  p++; // COMPLIANT - not covered by this rule
+  p--; // COMPLIANT - not covered by this rule
 }

cpp/common/src/codingstandards/cpp/Overflow.qll

@@ -1,5 +1,5 @@
 /**
- * This module provides predicates for checking whether an operation overflows or wraps.
+ * This module provides predicates for checking whether an integer operation overflows, underflows or wraps.
  */
 
 import cpp
@@ -10,10 +10,12 @@ import codingstandards.cpp.dataflow.TaintTracking
 import semmle.code.cpp.valuenumbering.GlobalValueNumbering
 
 /**
- * An operation that may overflow or underflow.
+ * An integer operation that may overflow, underflow or wrap.
  */
 class InterestingOverflowingOperation extends Operation {
   InterestingOverflowingOperation() {
+    // We are only interested in integer experssions
+    this.getUnderlyingType() instanceof IntegralType and
     // Might overflow or underflow
     (
       exprMightOverflowNegatively(this)