[AST] Pack UnaryOperator

[riccibruno]

Summary

Use the newly available space in the bit-fields of Stmt
to store some data from UnaryOperator.
This saves 8 bytes per UnaryOperator.

[dblaikie]

Looks good - thanks!

include/clang/AST/Expr.h

 ///
 /// Notes on various nodes:
 ///
 /// Real/Imag - These return the real/imag part of a complex operand.  If
 ///   applied to a non-complex value, the former returns its operand and the
 ///   later returns zero in the type of the operand.
 ///
 class UnaryOperator : public Expr {
+  Stmt *Val;
+
 public:
   typedef UnaryOperatorKind Opcode;
 
-private:
-  unsigned Opc : 5;
-  unsigned CanOverflow : 1;
-  SourceLocation Loc;
-  Stmt *Val;
-public:
   UnaryOperator(Expr *input, Opcode opc, QualType type, ExprValueKind VK,
                 ExprObjectKind OK, SourceLocation l, bool CanOverflow)
       : Expr(UnaryOperatorClass, type, VK, OK,
              input->isTypeDependent() || type->isDependentType(),
              input->isValueDependent(),
              (input->isInstantiationDependent() ||
               type->isInstantiationDependentType()),
              input->containsUnexpandedParameterPack()),
-        Opc(opc), CanOverflow(CanOverflow), Loc(l), Val(input) {}
+        Val(input) {
+    UnaryOperatorBits.Opc = opc;
+    UnaryOperatorBits.CanOverflow = CanOverflow;
+    UnaryOperatorBits.Loc = l;
+  }
 
   /// Build an empty unary operator.
-  explicit UnaryOperator(EmptyShell Empty)
-    : Expr(UnaryOperatorClass, Empty), Opc(UO_AddrOf) { }
+  explicit UnaryOperator(EmptyShell Empty) : Expr(UnaryOperatorClass, Empty) {
+    UnaryOperatorBits.Opc = UO_AddrOf;
+  }
 
-  Opcode getOpcode() const { return static_cast<Opcode>(Opc); }
-  void setOpcode(Opcode O) { Opc = O; }
+  Opcode getOpcode() const {
+    return static_cast<Opcode>(UnaryOperatorBits.Opc);
+  }
+  void setOpcode(Opcode Opc) { UnaryOperatorBits.Opc = Opc; }
 
   Expr *getSubExpr() const { return cast<Expr>(Val); }
   void setSubExpr(Expr *E) { Val = E; }
 
   /// getOperatorLoc - Return the location of the operator.
-  SourceLocation getOperatorLoc() const { return Loc; }
-  void setOperatorLoc(SourceLocation L) { Loc = L; }
+  SourceLocation getOperatorLoc() const { return UnaryOperatorBits.Loc; }
+  void setOperatorLoc(SourceLocation L) { UnaryOperatorBits.Loc = L; }
 
   /// Returns true if the unary operator can cause an overflow. For instance,
   ///   signed int i = INT_MAX; i++;
   ///   signed char c = CHAR_MAX; c++;
   /// Due to integer promotions, c++ is promoted to an int before the postfix
   /// increment, and the result is an int that cannot overflow. However, i++
   /// can overflow.
-  bool canOverflow() const { return CanOverflow; }
-  void setCanOverflow(bool C) { CanOverflow = C; }
+  bool canOverflow() const { return UnaryOperatorBits.CanOverflow; }
+  void setCanOverflow(bool C) { UnaryOperatorBits.CanOverflow = C; }
 
   /// isPostfix - Return true if this is a postfix operation, like x++.
   static bool isPostfix(Opcode Op) {
     return Op == UO_PostInc || Op == UO_PostDec;
   }
 
   /// isPrefix - Return true if this is a prefix operation, like --x.
   static bool isPrefix(Opcode Op) {
public:
   /// overloaded operator.
   static Opcode getOverloadedOpcode(OverloadedOperatorKind OO, bool Postfix);
 
   /// Retrieve the overloaded operator kind that corresponds to
   /// the given unary opcode.
   static OverloadedOperatorKind getOverloadedOperator(Opcode Opc);
 
   SourceLocation getBeginLoc() const LLVM_READONLY {
-    return isPostfix() ? Val->getBeginLoc() : Loc;
+    return isPostfix() ? Val->getBeginLoc() : getOperatorLoc();
   }
   SourceLocation getEndLoc() const LLVM_READONLY {
-    return isPostfix() ? Loc : Val->getEndLoc();
+    return isPostfix() ? getOperatorLoc() : Val->getEndLoc();
   }
-  SourceLocation getExprLoc() const LLVM_READONLY { return Loc; }
+  SourceLocation getExprLoc() const { return getOperatorLoc(); }
 
   static bool classof(const Stmt *T) {
     return T->getStmtClass() == UnaryOperatorClass;
   }
 
   // Iterators
   child_range children() { return child_range(&Val, &Val+1); }
   const_child_range children() const {

include/clang/AST/Stmt.h

protected:
   class CharacterLiteralBitfields {
     friend class CharacterLiteral;
 
     unsigned : NumExprBits;
 
     unsigned Kind : 3;
   };
 
+  class UnaryOperatorBitfields {
+    friend class UnaryOperator;
+
+    unsigned : NumExprBits;
+
+    unsigned Opc : 5;
+    unsigned CanOverflow : 1;
+
+    SourceLocation Loc;
+  };
+
   class UnaryExprOrTypeTraitExprBitfields {
     friend class UnaryExprOrTypeTraitExpr;
 
     unsigned : NumExprBits;
 
     unsigned Kind : 3;
     unsigned IsType : 1; // true if operand is a type, false if an expression.
   };
union {
     SwitchCaseBitfields SwitchCaseBits;
 
     // Expressions
     ExprBitfields ExprBits;
     PredefinedExprBitfields PredefinedExprBits;
     DeclRefExprBitfields DeclRefExprBits;
     FloatingLiteralBitfields FloatingLiteralBits;
     CharacterLiteralBitfields CharacterLiteralBits;
+    UnaryOperatorBitfields UnaryOperatorBits;
     UnaryExprOrTypeTraitExprBitfields UnaryExprOrTypeTraitExprBits;
     CallExprBitfields CallExprBits;
     CastExprBitfields CastExprBits;
     InitListExprBitfields InitListExprBits;
     PseudoObjectExprBitfields PseudoObjectExprBits;
 
     // C++ Expressions
     TypeTraitExprBitfields TypeTraitExprBits;