[NFC][CLANG] Fix static code analyzer concerns

[Manna]

Summary

Reported by Static Analyzer Tool:

Dereference null return value

Inside "CGExprConstant.cpp" file, in VisitObjCEncodeExpr(): Return value of function which returns null is dereferenced without checking.

This patch adds an assert.

[erichkeane]

clang/lib/CodeGen/CGExprConstant.cpp

1343

The assert message doesn't make sense here? This isn't an initializer for an array?

[Manna]

Thank you @erichkeane for reviews! I have updated assert message.

clang/lib/CodeGen/CGExprConstant.cpp

public:
 
   llvm::Constant *VisitObjCEncodeExpr(ObjCEncodeExpr *E, QualType T) {
     // This must be an @encode initializing an array in a static initializer.
     // Don't emit it as the address of the string, emit the string data itself
     // as an inline array.
     std::string Str;
     CGM.getContext().getObjCEncodingForType(E->getEncodedType(), Str);
     const ConstantArrayType *CAT = CGM.getContext().getAsConstantArrayType(T);
+    assert(CAT && "String data not of constant array type!");
 
     // Resize the string to the right size, adding zeros at the end, or
     // truncating as needed.
     Str.resize(CAT->getSize().getZExtValue(), '\0');
     return llvm::ConstantDataArray::getString(VMContext, Str, false);
   }
 
   llvm::Constant *VisitUnaryExtension(const UnaryOperator *E, QualType T) {