class.c

gcc-2.95.3 Linux下最常用的C编译器

      TYPE_NEEDS_CONSTRUCTING (t) |= TYPE_NEEDS_CONSTRUCTING (basetype);
      TYPE_NEEDS_DESTRUCTOR (t) |= TYPE_NEEDS_DESTRUCTOR (basetype);
      TYPE_HAS_COMPLEX_ASSIGN_REF (t) |= TYPE_HAS_COMPLEX_ASSIGN_REF (basetype);
      TYPE_HAS_COMPLEX_INIT_REF (t) |= TYPE_HAS_COMPLEX_INIT_REF (basetype);

      TYPE_OVERLOADS_CALL_EXPR (t) |= TYPE_OVERLOADS_CALL_EXPR (basetype);
      TYPE_OVERLOADS_ARRAY_REF (t) |= TYPE_OVERLOADS_ARRAY_REF (basetype);
      TYPE_OVERLOADS_ARROW (t) |= TYPE_OVERLOADS_ARROW (basetype);

      if (CLASSTYPE_COM_INTERFACE (basetype))
	{
	  CLASSTYPE_COM_INTERFACE (t) = 1;
	  if (i > 0)
	    cp_error
	      ("COM interface type `%T' must be the leftmost base class",
	       basetype);
	}
      else if (CLASSTYPE_COM_INTERFACE (t))
	{
	  cp_error ("COM interface type `%T' with non-COM base class `%T'",
		    t, basetype);
	  CLASSTYPE_COM_INTERFACE (t) = 0;
	}

      if (TYPE_VIRTUAL_P (basetype))
	{
	  /* Ensure that this is set from at least a virtual base
             class.  */
	  if (b->rtti == NULL_TREE)
	    b->rtti = CLASSTYPE_RTTI (basetype);

	  /* Don't borrow virtuals from virtual baseclasses.  */
	  if (TREE_VIA_VIRTUAL (base_binfo))
	    continue;

	  if (first_vfn_base_index < 0)
	    {
	      tree vfields;
	      first_vfn_base_index = i;

	      /* Update these two, now that we know what vtable we are
		 going to extend.  This is so that we can add virtual
		 functions, and override them properly.  */
	      TYPE_BINFO_VTABLE (t) = TYPE_BINFO_VTABLE (basetype);
	      TYPE_BINFO_VIRTUALS (t) = TYPE_BINFO_VIRTUALS (basetype);
	      b->has_virtual = CLASSTYPE_VSIZE (basetype);
	      b->vfield = CLASSTYPE_VFIELD (basetype);
	      b->vfields = copy_list (CLASSTYPE_VFIELDS (basetype));
	      vfields = b->vfields;
	      while (vfields)
		{
		  if (VF_BINFO_VALUE (vfields) == NULL_TREE
		      || ! TREE_VIA_VIRTUAL (VF_BINFO_VALUE (vfields)))
		    {
		      tree value = VF_BASETYPE_VALUE (vfields);
		      if (DECL_NAME (CLASSTYPE_VFIELD (value))
			  == DECL_NAME (CLASSTYPE_VFIELD (basetype)))
			VF_NORMAL_VALUE (b->vfields) = basetype;
		      else
			VF_NORMAL_VALUE (b->vfields) = VF_NORMAL_VALUE (vfields);
		    }
		  vfields = TREE_CHAIN (vfields);
		}
	      CLASSTYPE_VFIELD (t) = b->vfield;
	    }
	  else
	    {
	      /* Only add unique vfields, and flatten them out as we go.  */
	      tree vfields = CLASSTYPE_VFIELDS (basetype);
	      while (vfields)
		{
		  if (VF_BINFO_VALUE (vfields) == NULL_TREE
		      || ! TREE_VIA_VIRTUAL (VF_BINFO_VALUE (vfields)))
		    {
		      tree value = VF_BASETYPE_VALUE (vfields);
		      b->vfields = tree_cons (base_binfo, value, b->vfields);
		      if (DECL_NAME (CLASSTYPE_VFIELD (value))
			  == DECL_NAME (CLASSTYPE_VFIELD (basetype)))
			VF_NORMAL_VALUE (b->vfields) = basetype;
		      else
			VF_NORMAL_VALUE (b->vfields) = VF_NORMAL_VALUE (vfields);
		    }
		  vfields = TREE_CHAIN (vfields);
		}

	      if (b->has_virtual == 0)
		{
		  first_vfn_base_index = i;

		  /* Update these two, now that we know what vtable we are
		     going to extend.  This is so that we can add virtual
		     functions, and override them properly.  */
		  TYPE_BINFO_VTABLE (t) = TYPE_BINFO_VTABLE (basetype);
		  TYPE_BINFO_VIRTUALS (t) = TYPE_BINFO_VIRTUALS (basetype);
		  b->has_virtual = CLASSTYPE_VSIZE (basetype);
		  b->vfield = CLASSTYPE_VFIELD (basetype);
		  CLASSTYPE_VFIELD (t) = b->vfield;
		  /* When we install the first one, set the VF_NORMAL_VALUE
		     to be the current class, as this it is the most derived
		     class.  Hopefully, this is not set to something else
		     later.  (mrs) */
		  vfields = b->vfields;
		  while (vfields)
		    {
		      if (DECL_NAME (CLASSTYPE_VFIELD (t))
			  == DECL_NAME (CLASSTYPE_VFIELD (basetype)))
			{
			  VF_NORMAL_VALUE (vfields) = t;
			  /* There should only be one of them!  And it should
			     always be found, if we get into here.  (mrs)  */
			  break;
			}
		      vfields = TREE_CHAIN (vfields);
		    }
		}
	    }
	}
    }

  {
    tree vfields;
    /* Find the base class with the largest number of virtual functions.  */
    for (vfields = b->vfields; vfields; vfields = TREE_CHAIN (vfields))
      {
	if (CLASSTYPE_VSIZE (VF_BASETYPE_VALUE (vfields)) > b->max_has_virtual)
	  b->max_has_virtual = CLASSTYPE_VSIZE (VF_BASETYPE_VALUE (vfields));
	if (VF_DERIVED_VALUE (vfields)
	    && CLASSTYPE_VSIZE (VF_DERIVED_VALUE (vfields)) > b->max_has_virtual)
	  b->max_has_virtual = CLASSTYPE_VSIZE (VF_DERIVED_VALUE (vfields));
      }
  }

  if (b->vfield == 0)
    /* If all virtual functions come only from virtual baseclasses.  */
    return -1;

  /* Update the rtti base if we have a non-virtual base class version
     of it.  */
  b->rtti = CLASSTYPE_RTTI (BINFO_TYPE (TREE_VEC_ELT (binfos, first_vfn_base_index)));

  return first_vfn_base_index;
}

/* Set memoizing fields and bits of T (and its variants) for later use.
   MAX_HAS_VIRTUAL is the largest size of any T's virtual function tables.  */

static void
finish_struct_bits (t, max_has_virtual)
     tree t;
     int max_has_virtual;
{
  int i, n_baseclasses = CLASSTYPE_N_BASECLASSES (t);

  /* Fix up variants (if any).  */
  tree variants = TYPE_NEXT_VARIANT (t);
  while (variants)
    {
      /* These fields are in the _TYPE part of the node, not in
	 the TYPE_LANG_SPECIFIC component, so they are not shared.  */
      TYPE_HAS_CONSTRUCTOR (variants) = TYPE_HAS_CONSTRUCTOR (t);
      TYPE_HAS_DESTRUCTOR (variants) = TYPE_HAS_DESTRUCTOR (t);
      TYPE_NEEDS_CONSTRUCTING (variants) = TYPE_NEEDS_CONSTRUCTING (t);
      TYPE_NEEDS_DESTRUCTOR (variants) = TYPE_NEEDS_DESTRUCTOR (t);

      TYPE_USES_COMPLEX_INHERITANCE (variants) = TYPE_USES_COMPLEX_INHERITANCE (t);
      TYPE_VIRTUAL_P (variants) = TYPE_VIRTUAL_P (t);
      TYPE_USES_VIRTUAL_BASECLASSES (variants) = TYPE_USES_VIRTUAL_BASECLASSES (t);
      TYPE_USES_PVBASES (variants) = TYPE_USES_PVBASES (t);
      /* Copy whatever these are holding today.  */
      TYPE_MIN_VALUE (variants) = TYPE_MIN_VALUE (t);
      TYPE_MAX_VALUE (variants) = TYPE_MAX_VALUE (t);
      TYPE_FIELDS (variants) = TYPE_FIELDS (t);
      TYPE_SIZE (variants) = TYPE_SIZE (t);
      TYPE_SIZE_UNIT (variants) = TYPE_SIZE_UNIT (t);
      variants = TYPE_NEXT_VARIANT (variants);
    }

  if (n_baseclasses && max_has_virtual)
    {
      /* For a class w/o baseclasses, `finish_struct' has set
         CLASS_TYPE_ABSTRACT_VIRTUALS correctly (by definition). Similarly
         for a class who's base classes do not have vtables. When neither
         of these is true, we might have removed abstract virtuals (by
         providing a definition), added some (by declaring new ones), or
         redeclared ones from a base class. We need to recalculate what's
         really an abstract virtual at this point (by looking in the
         vtables).  */
      CLASSTYPE_ABSTRACT_VIRTUALS (t) = get_abstract_virtuals (t);
    }

  if (n_baseclasses)
    {
      /* Notice whether this class has type conversion functions defined.  */
      tree binfo = TYPE_BINFO (t);
      tree binfos = BINFO_BASETYPES (binfo);
      tree basetype;

      for (i = n_baseclasses-1; i >= 0; i--)
	{
	  basetype = BINFO_TYPE (TREE_VEC_ELT (binfos, i));

	  TYPE_HAS_CONVERSION (t) |= TYPE_HAS_CONVERSION (basetype);
	}
    }

  /* If this type has a copy constructor, force its mode to be BLKmode, and
     force its TREE_ADDRESSABLE bit to be nonzero.  This will cause it to
     be passed by invisible reference and prevent it from being returned in
     a register.

     Also do this if the class has BLKmode but can still be returned in
     registers, since function_cannot_inline_p won't let us inline
     functions returning such a type.  This affects the HP-PA.  */
  if (! TYPE_HAS_TRIVIAL_INIT_REF (t)
      || (TYPE_MODE (t) == BLKmode && ! aggregate_value_p (t)
	  && CLASSTYPE_NON_AGGREGATE (t)))
    {
      tree variants;
      DECL_MODE (TYPE_MAIN_DECL (t)) = BLKmode;
      for (variants = t; variants; variants = TYPE_NEXT_VARIANT (variants))
	{
	  TYPE_MODE (variants) = BLKmode;
	  TREE_ADDRESSABLE (variants) = 1;
	}
    }
}

/* Issue warnings about T having private constructors, but no friends,
   and so forth.  

   HAS_NONPRIVATE_METHOD is nonzero if T has any non-private methods or
   static members.  HAS_NONPRIVATE_STATIC_FN is nonzero if T has any
   non-private static member functions.  */

static void
maybe_warn_about_overly_private_class (t)
     tree t;
{
  int has_member_fn = 0;
  int has_nonprivate_method = 0;
  tree fn;

  if (!warn_ctor_dtor_privacy
      /* If the class has friends, those entities might create and
	 access instances, so we should not warn.  */
      || (CLASSTYPE_FRIEND_CLASSES (t)
	  || DECL_FRIENDLIST (TYPE_MAIN_DECL (t)))
      /* We will have warned when the template was declared; there's
	 no need to warn on every instantiation.  */
      || CLASSTYPE_TEMPLATE_INSTANTIATION (t))
    /* There's no reason to even consider warning about this 
       class.  */
    return;
    
  /* We only issue one warning, if more than one applies, because
     otherwise, on code like:

     class A {
       // Oops - forgot `public:'
       A();
       A(const A&);
       ~A();
     };

     we warn several times about essentially the same problem.  */

  /* Check to see if all (non-constructor, non-destructor) member
     functions are private.  (Since there are no friends or
     non-private statics, we can't ever call any of the private member
     functions.)  */
  for (fn = TYPE_METHODS (t); fn; fn = TREE_CHAIN (fn))
    /* We're not interested in compiler-generated methods; they don't
       provide any way to call private members.  */
    if (!DECL_ARTIFICIAL (fn)) 
      {
	if (!TREE_PRIVATE (fn))
	  {
	    if (DECL_STATIC_FUNCTION_P (fn)) 
	      /* A non-private static member function is just like a
		 friend; it can create and invoke private member
		 functions, and be accessed without a class
		 instance.  */
	      return;
		
	    has_nonprivate_method = 1;
	    break;
	  }
	else if (!DECL_CONSTRUCTOR_P (fn) && !DECL_DESTRUCTOR_P (fn))
	  has_member_fn = 1;
      } 

  if (!has_nonprivate_method && has_member_fn) 
    {
      /* There are no non-private methods, and there's at least one
	 private member function that isn't a constructor or
	 destructor.  (If all the private members are
	 constructors/destructors we want to use the code below that
	 issues error messages specifically referring to
	 constructors/destructors.)  */
      int i;
      tree binfos = BINFO_BASETYPES (TYPE_BINFO (t));
      for (i = 0; i < CLASSTYPE_N_BASECLASSES (t); i++)
	if (TREE_VIA_PUBLIC (TREE_VEC_ELT (binfos, i))
	    || TREE_VIA_PROTECTED (TREE_VEC_ELT (binfos, i)))
	  {
	    has_nonprivate_method = 1;
	    break;
	  }
      if (!has_nonprivate_method) 
	{
	  cp_warning ("all member functions in class `%T' are private", t);
	  return;
	}
    }

  /* Even if some of the member functions are non-private, the class
     won't be useful for much if all the constructors or destructors
     are private: such an object can never be created or destroyed.  */
  if (TYPE_HAS_DESTRUCTOR (t))
    {
      tree dtor = TREE_VEC_ELT (CLASSTYPE_METHOD_VEC (t), 1);

      if (TREE_PRIVATE (dtor))
	{
	  cp_warning ("`%#T' only defines a private destructor and has no friends",
		      t);
	  return;
	}
    }

  if (TYPE_HAS_CONSTRUCTOR (t))
    {
      int nonprivate_ctor = 0;
	  
      /* If a non-template class does not define a copy
	 constructor, one is defined for it, enabling it to avoid
	 this warning.  For a template class, this does not
	 happen, and so we would normally get a warning on:

	   template <class T> class C { private: C(); };  
	  
	 To avoid this asymmetry, we check TYPE_HAS_INIT_REF.  All
	 complete non-template or fully instantiated classes have this
	 flag set.  */
      if (!TYPE_HAS_INIT_REF (t))
	nonprivate_ctor = 1;
      else 
	for (fn = TREE_VEC_ELT (CLASSTYPE_METHOD_VEC (t), 0);
	     fn;
	     fn = OVL_NEXT (fn)) 
	  {
	    tree ctor = OVL_CURRENT (fn);
	    /* Ideally, we wouldn't count copy constructors (or, in
	       fact, any constructor that takes an argument of the
	       class type as a parameter) because such things cannot
	       be used to construct an instance of the class unless
	       you already have one.  But, for now at least, we're
	       more generous.  */
	    if (! TREE_PRIVATE (ctor))
	      {
		nonprivate_ctor = 1;
		break;
	      }
	  }

      if (nonprivate_ctor == 0)
	{
	  cp_warning ("`%#T' only defines private constructors and has no friends",
		      t);
	  return;
	}
    }
}


/* Warn about duplicate methods in fn_fields.  Also compact method
   lists so that lookup can be made faster.

   Data Structure: List of method lists.  The outer list is a
   TREE_LIST, whose TREE_PURPOSE field is the field name and the
   TREE_VALUE is the DECL_CHAIN of the FUNCTION_DECLs.  TREE_CHAIN
   links the entire list of methods for TYPE_METHODS.  Friends are
   chained in the same way as member functions (? TREE_CHAIN or
   DECL_CHAIN), but they live in the TREE_TYPE field of the outer
   list.  That allows them to be quickly deleted, and requires no
   extra storage.

   If there are any constructors/destructors, they are moved to the
   front of the list.  This makes pushclass more efficient.

   We also link each field which has shares a name with its baseclass
   to the head of the list of fields for that base class.  This allows
   us to reduce search time in places like `build_method_call' to
   consider only reasonably likely functions.   */

static void
finish_struct_methods (t)
     tree t;
{
  tree fn_fields;
  tree method_vec = CLASSTYPE_METHOD_VEC (t);
  tree ctor_name = constructor_name (t);

  /* First fill in entry 0 with the constructors, entry 1 with destructors,
     and the next few with type conversion operators (if any).  */
  for (fn_fields = TYPE_METHODS (t); fn_fields; 
       fn_fields = TREE_CHAIN (fn_fields))
    {
      tree fn_name = DECL_NAME (fn_fields);

      /* Clear out this flag.

	 @@ Doug may figure out how to break
	 @@ this with nested classes and friends.  */
      DECL_IN_AGGR_P (fn_fields) = 0;

      /* Note here th