Add MISRA 18.4 check (#1966)

* Add MISRA 18.4 check

* Fixup

* Quickfix

addons/misra.py

@@ -1611,6 +1611,18 @@ class MisraChecker:
             if var and var.isArgument:
                 self.reportError(token, 17, 8)
 
+    def misra_18_4(self, data):
+        for token in data.tokenlist:
+            if not token.str in ('+', '-', '+=', '-='):
+                continue
+            if token.astOperand1 is None or token.astOperand2 is None:
+                continue
+            vt1 = token.astOperand1.valueType
+            vt2 = token.astOperand2.valueType
+            if vt1 and vt1.pointer > 0:
+                self.reportError(token, 18, 4)
+            elif vt2 and vt2.pointer > 0:
+                self.reportError(token, 18, 4)
 
     def misra_18_5(self, data):
         for var in data.variables:
@@ -2304,6 +2316,7 @@ class MisraChecker:
                 self.misra_17_6(data.rawTokens)
             self.misra_17_7(cfg)
             self.misra_17_8(cfg)
+            self.misra_18_4(cfg)
             self.misra_18_5(cfg)
             self.misra_18_7(cfg)
             self.misra_18_8(cfg)

addons/test/misra-test.c

@@ -503,6 +503,20 @@ void misra_17_8(int x) {
   x = 3; // 17.8
 }
 
+void misra_18_4()
+{
+  int b = 42;
+  int *bp = &b;
+  bp += 1; // 18.4
+  bp -= 2; // 18.4
+  int *p = bp - 2; // 18.4
+  int *ab = &b + 1; // 18.4
+  p = bp + p; // 18.4
+  bp = 1 + p + 1; // 18.4
+  b += 19; // no-warning
+  b = b + 9; // no-warning
+}
+
 void misra_18_5() {
   int *** p;  // 18.5
 }