Fix #9498: false positive: misra-c2012-18.8 (#5600)

Author: swasti16

addons/misra.py

@@ -897,6 +897,14 @@ def isConstantExpression(expr):
         return False
     return True
 
+def isUnknownConstantExpression(expr):
+    if expr.isName and not isEnumConstant(expr) and expr.variable is None:
+        return True
+    if expr.astOperand1 and isUnknownConstantExpression(expr.astOperand1):
+        return True
+    if expr.astOperand2 and isUnknownConstantExpression(expr.astOperand2):
+        return True
+    return False
 
 def isUnsignedInt(expr):
     return expr and expr.valueType and expr.valueType.type in ('short', 'int') and expr.valueType.sign == 'unsigned'
@@ -3258,6 +3266,32 @@ def misra_17_3(self, cfg):
                 tok = tok.next
 
     def misra_config(self, data):
+        for var in data.variables:
+            if not var.isArray or var.nameToken is None or not cppcheckdata.simpleMatch(var.nameToken.next, '['):
+                continue
+            tok = var.nameToken.next
+            while tok.str == '[':
+                sz = tok.astOperand2
+                if sz and sz.getKnownIntValue() is None:
+                    has_var = False
+                    unknown_constant = False
+                    tokens = [sz]
+                    while len(tokens) > 0:
+                        t = tokens[-1]
+                        tokens = tokens[:-1]
+                        if t:
+                            if t.isName and t.getKnownIntValue() is None:
+                                if t.varId or t.variable:
+                                    has_var = True
+                                    continue
+                                unknown_constant = True
+                                self.report_config_error(tok, 'Unknown constant {}, please review configuration'.format(t.str))
+                            if t.isArithmeticalOp:
+                                tokens += [t.astOperand1, t.astOperand2]
+                    if not unknown_constant and not has_var:
+                        self.report_config_error(tok, 'Unknown array size, please review configuration')
+                tok = tok.link.next
+
         for token in data.tokenlist:
             if token.str not in ("while", "if"):
                 continue
@@ -3367,7 +3401,7 @@ def misra_18_8(self, data):
             # Unknown define or syntax error
             if not typetok.astOperand2:
                 continue
-            if not isConstantExpression(typetok.astOperand2):
+            if not isConstantExpression(typetok.astOperand2) and not isUnknownConstantExpression(typetok.astOperand2):
                 self.reportError(var.nameToken, 18, 8)
 
     def misra_19_2(self, data):

addons/misra_9.py

@@ -396,38 +396,6 @@ def unwindAndContinue(self):
                     break
 
 def misra_9_x(self, data, rule, rawTokens = None):
-    # If there are arrays with unknown size constants then we need to warn about missing configuration
-    # and bailout
-    has_config_errors = False
-    for var in data.variables:
-        if not var.isArray or var.nameToken is None or not cppcheckdata.simpleMatch(var.nameToken.next,'['):
-            continue
-        tok = var.nameToken.next
-        while tok.str == '[':
-            sz = tok.astOperand2
-            if sz and sz.getKnownIntValue() is None:
-                has_var = False
-                unknown_constant = False
-                tokens = [sz]
-                while len(tokens) > 0:
-                    t = tokens[-1]
-                    tokens = tokens[:-1]
-                    if t:
-                        if t.isName and t.getKnownIntValue() is None:
-                            if t.varId or t.variable:
-                                has_var = True
-                                continue
-                            unknown_constant = True
-                            cppcheckdata.reportError(sz, 'error', 'Unknown constant {}, please review configuration'.format(t.str), 'misra', 'config')
-                            has_config_errors = True
-                        if t.isArithmeticalOp:
-                            tokens += [t.astOperand1, t.astOperand2]
-                if not unknown_constant and not has_var:
-                    cppcheckdata.reportError(sz, 'error', 'Unknown array size, please review configuration', 'misra', 'config')
-                    has_config_errors = True
-            tok = tok.link.next
-    if has_config_errors:
-        return
 
     parser = InitializerParser()
 

addons/test/misra/misra-test.c

@@ -1783,6 +1783,8 @@ static void misra_18_8(int x) {
   int buf1[10];
   int buf2[sizeof(int)];
   int vla[x]; // 18.8
+  // #9498
+  int vlb[y]; // config
   static const unsigned char arr18_8_1[] = UNDEFINED_ID;
   static uint32_t enum_test_0[R18_8_ENUM_CONSTANT_0] = {0};
 }