Refactoring, reuse and improve isVariableChangedByFunction()

Author: danmar

lib/astutils.cpp

@@ -398,6 +398,16 @@ bool isReturnScope(const Token * const endToken)
     return false;
 }
 
+bool isVariableChangedByFunctionCall(const Token *tok, unsigned int varid, const Settings *settings, bool *inconclusive)
+{
+    if (!tok)
+        return false;
+    if (tok->varId() == varid)
+        return isVariableChangedByFunctionCall(tok, settings, inconclusive);
+    return isVariableChangedByFunctionCall(tok->astOperand1(), varid, settings, inconclusive) ||
+           isVariableChangedByFunctionCall(tok->astOperand2(), varid, settings, inconclusive);
+}
+
 bool isVariableChangedByFunctionCall(const Token *tok, const Settings *settings, bool *inconclusive)
 {
     if (!tok)
@@ -411,7 +421,17 @@ bool isVariableChangedByFunctionCall(const Token *tok, const Settings *settings,
         ;
     else if (Token::Match(tok->tokAt(addressOf?-2:-1), "[(,] &| %name% [,)]"))
         ;
-    else
+    else if (Token::Match(tok->tokAt(addressOf?-2:-1), "[?:] &| %name% [:,)]")) {
+        const Token *parent = tok->astParent();
+        if (parent == tok->previous() && parent->str() == "&")
+            parent = parent->astParent();
+        while (Token::Match(parent, "[?:]"))
+            parent = parent->astParent();
+        while (Token::simpleMatch(parent, ","))
+            parent = parent->astParent();
+        if (!parent || parent->str() != "(")
+            return false;
+    } else
         return false;
 
     // reinterpret_cast etc..

lib/astutils.h

@@ -74,6 +74,17 @@ bool isWithoutSideEffects(bool cpp, const Token* tok);
 /** Is scope a return scope (scope will unconditionally return) */
 bool isReturnScope(const Token *endToken);
 
+/** Is variable changed by function call?
+ * In case the answer of the question is inconclusive, e.g. because the function declaration is not known
+ * the return value is false and the output parameter inconclusive is set to true
+ *
+ * @param tok           ast tree
+ * @param varid         Variable Id
+ * @param settings      program settings
+ * @param inconclusive  pointer to output variable which indicates that the answer of the question is inconclusive
+ */
+bool isVariableChangedByFunctionCall(const Token *tok, unsigned int varid, const Settings *settings, bool *inconclusive);
+
 /** Is variable changed by function call?
  * In case the answer of the question is inconclusive, e.g. because the function declaration is not known
  * the return value is false and the output parameter inconclusive is set to true

lib/valueflow.cpp

@@ -115,27 +115,6 @@ static void changeKnownToPossible(std::list<ValueFlow::Value> &values)
         it->changeKnownToPossible();
 }
 
-static bool mightBeNonConstPointerFunctionArg(const Token *tok)
-{
-    // TODO: check if argument might be non-const pointer
-    const Token *parent = tok->astParent();
-    while (parent && parent->str() == ",")
-        parent = parent->astParent();
-    return (parent && Token::Match(parent->previous(), "%name% ("));
-}
-
-static const Token *findVariableInAST(const Token *tok, unsigned int varid)
-{
-    if (!tok)
-        return nullptr;
-    if (tok->varId() == varid)
-        return tok;
-    const Token *ret1 = findVariableInAST(tok->astOperand1(), varid);
-    if (ret1)
-        return ret1;
-    return findVariableInAST(tok->astOperand2(), varid);
-}
-
 /**
  * Is condition always false when variable has given value?
  * \param condition   top ast token in condition
@@ -1858,7 +1837,7 @@ static bool valueFlowForward(Token * const               startToken,
                 std::list<ValueFlow::Value>::const_iterator it;
                 for (it = values.begin(); it != values.end(); ++it)
                     valueFlowAST(const_cast<Token*>(expr), varid, *it, settings);
-                if ((expr->valueType() && expr->valueType()->pointer) && mightBeNonConstPointerFunctionArg(tok2) && findVariableInAST(expr,varid))
+                if (isVariableChangedByFunctionCall(expr, varid, settings, nullptr))
                     changeKnownToPossible(values);
             } else {
                 std::list<ValueFlow::Value>::const_iterator it;
@@ -1871,8 +1850,7 @@ static bool valueFlowForward(Token * const               startToken,
                     else
                         valueFlowAST(const_cast<Token*>(op2), varid, *it, settings);
                 }
-
-                if (mightBeNonConstPointerFunctionArg(tok2) && findVariableInAST(op2,varid))
+                if (isVariableChangedByFunctionCall(op2, varid, settings, nullptr))
                     changeKnownToPossible(values);
             }