Add check for MISRA-C 2012 rule 3.2 and test cases. (#2269)

* Add check for MISRA-C 2012 rule 3.2 and test cases.

* Fix formatting of MISRA rule 3.2 example.

addons/misra.py

@@ -746,6 +746,19 @@ class MisraChecker:
                 if ((not starts_with_double_slash) and '//' in s) or '/*' in s:
                     self.reportError(token, 3, 1)
 
+    def misra_3_2(self, rawTokens):
+        for token in rawTokens:
+            if token.str.startswith('//'):
+                # Check for comment ends with trigraph which might be replaced
+                # by a backslash.
+                if token.str.endswith('??/'):
+                    self.reportError(token, 3, 2)
+                # Check for comment which has been merged with subsequent line
+                # because it ends with backslash.
+                # The last backslash is no more part of the comment token thus
+                # check if next token exists and compare line numbers.
+                elif (token.next != None) and (token.linenr == token.next.linenr):
+                    self.reportError(token, 3, 2)
 
     def misra_4_1(self, rawTokens):
         for token in rawTokens:
@@ -2404,6 +2417,7 @@ class MisraChecker:
 
             if cfgNumber == 1:
                 self.misra_3_1(data.rawTokens)
+                self.misra_3_2(data.rawTokens)
                 self.misra_4_1(data.rawTokens)
                 self.misra_4_2(data.rawTokens)
             self.misra_5_1(cfg)

addons/test/misra/misra-test.c

@@ -25,6 +25,22 @@ typedef unsigned long long u64;
 
 // http://example.com // no warning
 
+void misra_3_2(int enable)
+{
+    // This won't generate a violation because of subsequent blank line \
+	
+    int y = 0;
+    int x = 0;  // 3.2 non-compliant comment ends with backslash \
+    if (enable != 0)
+    {
+        ++x;    // This is always executed
+        // 3.2 potentially non-compliant comment ends with trigraph resolved to backslash ??/
+        ++y;    // This is hidden if trigraph replacement is active
+    }
+
+    (void)printf("x=%i, y=%i\n", x, y);
+}
+
 extern int misra_5_1_extern_var_hides_var_x;
 extern int misra_5_1_extern_var_hides_var_y; //5.1
 int misra_5_1_var_hides_var________a;