Merge pull request #654 from geoffw0/lossyresultcast

CPP: Work on Lossy function result cast query

cpp/ql/test/query-tests/Likely Bugs/Conversion/LossyFunctionResultCast/ImplicitDowncastFromBitfield.expected

@@ -0,0 +1,9 @@
+| test.cpp:33:6:33:13 | call to getFloat | Return value of type float is implicitly converted to bool here. |
+| test.cpp:35:13:35:20 | call to getFloat | Return value of type float is implicitly converted to int here. |
+| test.cpp:38:6:38:14 | call to getDouble | Return value of type double is implicitly converted to bool here. |
+| test.cpp:40:13:40:21 | call to getDouble | Return value of type double is implicitly converted to int here. |
+| test.cpp:43:6:43:12 | call to getMyLD | Return value of type long double is implicitly converted to bool here. |
+| test.cpp:45:13:45:19 | call to getMyLD | Return value of type long double is implicitly converted to int here. |
+| test.cpp:101:10:101:12 | call to pow | Return value of type double is implicitly converted to int here. |
+| test.cpp:103:10:103:12 | call to pow | Return value of type double is implicitly converted to int here. |
+| test.cpp:105:10:105:12 | call to pow | Return value of type double is implicitly converted to int here. |

cpp/ql/test/query-tests/Likely Bugs/Conversion/LossyFunctionResultCast/ImplicitDowncastFromBitfield.qlref

@@ -0,0 +1 @@
+Likely Bugs/Conversion/LossyFunctionResultCast.ql

cpp/ql/test/query-tests/Likely Bugs/Conversion/LossyFunctionResultCast/test.cpp

@@ -0,0 +1,131 @@
+
+typedef long double MYLD;
+
+bool getBool();
+int getInt();
+float getFloat();
+double getDouble();
+MYLD getMyLD();
+float *getFloatPtr();
+float &getFloatRef();
+const float &getConstFloatRef();
+
+void setPosInt(int x);
+void setPosFloat(float x);
+
+double round(double x);
+float roundf(float x);
+
+void test1()
+{
+	// simple
+
+	if (getBool())
+	{
+		setPosInt(getBool());
+		setPosFloat(getBool());
+	}
+	if (getInt())
+	{
+		setPosInt(getInt());
+		setPosFloat(getInt());
+	}
+	if (getFloat()) // BAD
+	{
+		setPosInt(getFloat()); // BAD
+		setPosFloat(getFloat());
+	}
+	if (getDouble()) // BAD
+	{
+		setPosInt(getDouble()); // BAD
+		setPosFloat(getDouble());
+	}
+	if (getMyLD()) // BAD
+	{
+		setPosInt(getMyLD()); // BAD
+		setPosFloat(getMyLD());
+	}
+	if (getFloatPtr())
+	{
+		// ...
+	}
+	if (getFloatRef()) // BAD [NOT DETECTED]
+	{
+		setPosInt(getFloatRef()); // BAD [NOT DETECTED]
+		setPosFloat(getFloatRef());
+	}
+	if (getConstFloatRef()) // BAD [NOT DETECTED]
+	{
+		setPosInt(getConstFloatRef()); // BAD [NOT DETECTED]
+		setPosFloat(getConstFloatRef());
+	}
+
+	// explicit cast
+
+	if ((bool)getInt())
+	{
+		setPosInt(getInt());
+		setPosFloat((float)getInt());
+	}
+	if ((bool)getFloat())
+	{
+		setPosInt((int)getFloat());
+		setPosFloat(getFloat());
+	}
+
+	// explicit rounding
+
+	if (roundf(getFloat()))
+	{
+		setPosInt(roundf(getFloat()));
+		setPosFloat(roundf(getFloat()));
+	}
+	if (round(getDouble()))
+	{
+		setPosInt(round(getDouble()));
+		setPosFloat(round(getDouble()));
+	}
+}
+
+double pow(double x, double y);
+
+int test2(double v, double w, int n)
+{
+	switch (n)
+	{
+	case 1:
+		return pow(2, v); // GOOD
+	case 2:
+		return pow(10, v); // GOOD
+	case 3:
+		return pow(2.5, v); // BAD
+	case 4:
+		return pow(v, 2); // BAD
+	case 5:
+		return pow(v, w); // BAD
+	};
+}
+
+double myRound1(double v)
+{
+	return round(v);
+}
+
+double myRound2(double v)
+{
+	double result = round(v);
+
+	return result;
+}
+
+double myRound3(double v)
+{
+	return (v > 0) ? round(v) : 0;
+}
+
+void test3()
+{
+	int i = myRound1(1.5); // GOOD
+	int j = myRound2(2.5); // GOOD
+	int k = myRound3(3.5); // GOOD
+}