[C++ PATCH] Kill lang_type_ptrmem

[C++ PATCH] Kill lang_type_ptrmem

[Nathan Sidwell]

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In figuring out how to stream out lang_type on the modules branch, I 
noticed that we had an unused TYPE_LANG_SLOT_1 that we could use for 
pointers to member functions.  That means lang_type_ptrmem isn't needed 
and consequently neither is is_lang_type_class field.

This patch nukes that bit of polymorphism.  Applied to trunk.

nathan
-- 
Nathan Sidwell

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2017-06-02  Nathan Sidwell  <nathan@acm.org>

	cp/
	Remove lang_type_ptrmem.
	* cp-tree.h (lang_type_header): Remove is_lang_type_class. Move
	into ...
	(lang_type_class): ... this.  Reorder bitfields.  Rename to ...
	(lang_type): ... this.  Delete old definition.
	(lang_type_ptrmem): Delete.
	(LANG_TYPE_CLASS_CHECK): Simply get TYPE_LANG_SPECIFIC.  Adjust uses.
	(LANG_TYPE_PTRMEM_CHECK): Delete.
	(TYPE_GET_PTRMEMFUNC_TYPE, TYPE_SET_PTRMEMFUNC_TYPE): Delete.
	(TYPE_PTRMEMFUNC_TYPE): New.  Use TYPE_LANG_SLOT_1.
	* decl.c (build_ptrmemfunc_type): Adjust.
	* lex.c (copy_lang_type): Remove lang_type_ptrmem handling.
	(maybe_add_lang_type_raw): Don't set u.c.h.is_lang_type_class.

	objcp/
	* objcp-decl.h (SIZEOF_OBJC_TYPE_LANG_SPECIFIC): Use lang_type.
	(ALLOC_OBJC_TYPE_LANG_SPECIFIC): Use it.  Don't set
	u.c.h.is_lang_type_class.

Index: cp/class.c
===================================================================
--- cp/class.c	(revision 248821)
+++ cp/class.c	(working copy)
@@ -6025,7 +6025,7 @@ check_bases_and_members (tree t)
 
   /* Figure out whether or not we will need a cookie when dynamically
      allocating an array of this type.  */
-  TYPE_LANG_SPECIFIC (t)->u.c.vec_new_uses_cookie
+  LANG_TYPE_CLASS_CHECK (t)->vec_new_uses_cookie
     = type_requires_array_cookie (t);
 }
 
Index: cp/cp-tree.h
===================================================================
--- cp/cp-tree.h	(revision 248821)
+++ cp/cp-tree.h	(working copy)
@@ -460,6 +460,7 @@ extern GTY(()) tree cp_global_trees[CPTI
    TYPE_LANG_SLOT_1
      For an ENUMERAL_TYPE, this is ENUM_TEMPLATE_INFO.
      For a FUNCTION_TYPE or METHOD_TYPE, this is TYPE_RAISES_EXCEPTIONS
+     For a POINTER_TYPE (to a METHOD_TYPE), this is TYPE_PTRMEMFUNC_TYPE
 
   BINFO_VIRTUALS
      For a binfo, this is a TREE_LIST.  There is an entry for each
@@ -1849,22 +1850,6 @@ struct GTY (()) tree_pair_s {
 };
 typedef tree_pair_s *tree_pair_p;
 
-/* This is a few header flags for 'struct lang_type'.  Actually,
-   all but the first are used only for lang_type_class; they
-   are put in this structure to save space.  */
-struct GTY(()) lang_type_header {
-  BOOL_BITFIELD is_lang_type_class : 1;
-
-  BOOL_BITFIELD has_type_conversion : 1;
-  BOOL_BITFIELD has_copy_ctor : 1;
-  BOOL_BITFIELD has_default_ctor : 1;
-  BOOL_BITFIELD const_needs_init : 1;
-  BOOL_BITFIELD ref_needs_init : 1;
-  BOOL_BITFIELD has_const_copy_assign : 1;
-
-  BOOL_BITFIELD spare : 1;
-};
-
 /* This structure provides additional information above and beyond
    what is provide in the ordinary tree_type.  In the past, we used it
    for the types of class types, template parameters types, typename
@@ -1878,11 +1863,17 @@ struct GTY(()) lang_type_header {
    many (i.e., thousands) of classes can easily be generated.
    Therefore, we should endeavor to keep the size of this structure to
    a minimum.  */
-struct GTY(()) lang_type_class {
-  struct lang_type_header h;
-
+struct GTY(()) lang_type {
   unsigned char align;
 
+  unsigned has_type_conversion : 1;
+  unsigned has_copy_ctor : 1;
+  unsigned has_default_ctor : 1;
+  unsigned const_needs_init : 1;
+  unsigned ref_needs_init : 1;
+  unsigned has_const_copy_assign : 1;
+  unsigned use_template : 2;
+
   unsigned has_mutable : 1;
   unsigned com_interface : 1;
   unsigned non_pod_class : 1;
@@ -1899,6 +1890,7 @@ struct GTY(()) lang_type_class {
   unsigned anon_aggr : 1;
   unsigned non_zero_init : 1;
   unsigned empty_p : 1;
+  /* 32 bits allocated.  */
 
   unsigned vec_new_uses_cookie : 1;
   unsigned declared_class : 1;
@@ -1909,25 +1901,24 @@ struct GTY(()) lang_type_class {
   unsigned fields_readonly : 1;
   unsigned ptrmemfunc_flag : 1;
 
-  unsigned use_template : 2;
   unsigned was_anonymous : 1;
   unsigned lazy_default_ctor : 1;
   unsigned lazy_copy_ctor : 1;
   unsigned lazy_copy_assign : 1;
   unsigned lazy_destructor : 1;
   unsigned has_const_copy_ctor : 1;
-
   unsigned has_complex_copy_ctor : 1;
   unsigned has_complex_copy_assign : 1;
+
   unsigned non_aggregate : 1;
   unsigned has_complex_dflt : 1;
   unsigned has_list_ctor : 1;
   unsigned non_std_layout : 1;
   unsigned is_literal : 1;
   unsigned lazy_move_ctor : 1;
-
   unsigned lazy_move_assign : 1;
   unsigned has_complex_move_ctor : 1;
+
   unsigned has_complex_move_assign : 1;
   unsigned has_constexpr_ctor : 1;
   unsigned unique_obj_representations : 1;
@@ -1940,7 +1931,7 @@ struct GTY(()) lang_type_class {
   /* There are some bits left to fill out a 32-bit word.  Keep track
      of this by updating the size of this bitfield whenever you add or
      remove a flag.  */
-  unsigned dummy : 2;
+  unsigned dummy : 4;
 
   tree primary_base;
   vec<tree_pair_s, va_gc> *vcall_indices;
@@ -1968,40 +1959,9 @@ struct GTY(()) lang_type_class {
   tree lambda_expr;
 };
 
-struct GTY(()) lang_type_ptrmem {
-  struct lang_type_header h;
-  tree record;
-};
-
-struct GTY(()) lang_type {
-  union lang_type_u
-  {
-    struct lang_type_header GTY((skip (""))) h;
-    struct lang_type_class  GTY((tag ("1"))) c;
-    struct lang_type_ptrmem GTY((tag ("0"))) ptrmem;
-  } GTY((desc ("%h.h.is_lang_type_class"))) u;
-};
-
-#if defined ENABLE_TREE_CHECKING && (GCC_VERSION >= 2007)
-
-#define LANG_TYPE_CLASS_CHECK(NODE) __extension__		\
-({  struct lang_type *lt = TYPE_LANG_SPECIFIC (NODE);		\
-    if (! lt->u.h.is_lang_type_class)				\
-      lang_check_failed (__FILE__, __LINE__, __FUNCTION__);	\
-    &lt->u.c; })
-
-#define LANG_TYPE_PTRMEM_CHECK(NODE) __extension__		\
-({  struct lang_type *lt = TYPE_LANG_SPECIFIC (NODE);		\
-    if (lt->u.h.is_lang_type_class)				\
-      lang_check_failed (__FILE__, __LINE__, __FUNCTION__);	\
-    &lt->u.ptrmem; })
-
-#else
-
-#define LANG_TYPE_CLASS_CHECK(NODE) (&TYPE_LANG_SPECIFIC (NODE)->u.c)
-#define LANG_TYPE_PTRMEM_CHECK(NODE) (&TYPE_LANG_SPECIFIC (NODE)->u.ptrmem)
-
-#endif /* ENABLE_TREE_CHECKING */
+/* We used to have a variant type for lang_type.  Keep the name of the
+   checking accessor for the sole survivor.  */
+#define LANG_TYPE_CLASS_CHECK(NODE) (TYPE_LANG_SPECIFIC (NODE))
 
 /* Nonzero for _CLASSTYPE means that operator delete is defined.  */
 #define TYPE_GETS_DELETE(NODE) (LANG_TYPE_CLASS_CHECK (NODE)->gets_delete)
@@ -2016,7 +1976,7 @@ struct GTY(()) lang_type {
 /* Nonzero means that this _CLASSTYPE node defines ways of converting
    itself to other types.  */
 #define TYPE_HAS_CONVERSION(NODE) \
-  (LANG_TYPE_CLASS_CHECK (NODE)->h.has_type_conversion)
+  (LANG_TYPE_CLASS_CHECK (NODE)->has_type_conversion)
 
 /* Nonzero means that NODE (a class type) has a default constructor --
    but that it has not yet been declared.  */
@@ -2059,10 +2019,10 @@ struct GTY(()) lang_type {
 /* True iff the class type NODE has an "operator =" whose parameter
    has a parameter of type "const X&".  */
 #define TYPE_HAS_CONST_COPY_ASSIGN(NODE) \
-  (LANG_TYPE_CLASS_CHECK (NODE)->h.has_const_copy_assign)
+  (LANG_TYPE_CLASS_CHECK (NODE)->has_const_copy_assign)
 
 /* Nonzero means that this _CLASSTYPE node has an X(X&) constructor.  */
-#define TYPE_HAS_COPY_CTOR(NODE) (LANG_TYPE_CLASS_CHECK (NODE)->h.has_copy_ctor)
+#define TYPE_HAS_COPY_CTOR(NODE) (LANG_TYPE_CLASS_CHECK (NODE)->has_copy_ctor)
 #define TYPE_HAS_CONST_COPY_CTOR(NODE) \
   (LANG_TYPE_CLASS_CHECK (NODE)->has_const_copy_ctor)
 
@@ -2214,7 +2174,7 @@ struct GTY(()) lang_type {
 
 /* Nonzero means that this type has an X() constructor.  */
 #define TYPE_HAS_DEFAULT_CONSTRUCTOR(NODE) \
-  (LANG_TYPE_CLASS_CHECK (NODE)->h.has_default_ctor)
+  (LANG_TYPE_CLASS_CHECK (NODE)->has_default_ctor)
 
 /* Nonzero means that this type contains a mutable member.  */
 #define CLASSTYPE_HAS_MUTABLE(NODE) (LANG_TYPE_CLASS_CHECK (NODE)->has_mutable)
@@ -2283,17 +2243,17 @@ struct GTY(()) lang_type {
    which have no specified initialization.  */
 #define CLASSTYPE_READONLY_FIELDS_NEED_INIT(NODE)	\
   (TYPE_LANG_SPECIFIC (NODE)				\
-   ? LANG_TYPE_CLASS_CHECK (NODE)->h.const_needs_init : 0)
+   ? LANG_TYPE_CLASS_CHECK (NODE)->const_needs_init : 0)
 #define SET_CLASSTYPE_READONLY_FIELDS_NEED_INIT(NODE, VALUE) \
-  (LANG_TYPE_CLASS_CHECK (NODE)->h.const_needs_init = (VALUE))
+  (LANG_TYPE_CLASS_CHECK (NODE)->const_needs_init = (VALUE))
 
 /* Nonzero if this class has ref members
    which have no specified initialization.  */
 #define CLASSTYPE_REF_FIELDS_NEED_INIT(NODE)		\
   (TYPE_LANG_SPECIFIC (NODE)				\
-   ? LANG_TYPE_CLASS_CHECK (NODE)->h.ref_needs_init : 0)
+   ? LANG_TYPE_CLASS_CHECK (NODE)->ref_needs_init : 0)
 #define SET_CLASSTYPE_REF_FIELDS_NEED_INIT(NODE, VALUE) \
-  (LANG_TYPE_CLASS_CHECK (NODE)->h.ref_needs_init = (VALUE))
+  (LANG_TYPE_CLASS_CHECK (NODE)->ref_needs_init = (VALUE))
 
 /* Nonzero if this class is included from a header file which employs
    `#pragma interface', and it is not included in its implementation file.  */
@@ -4296,21 +4256,10 @@ more_aggr_init_expr_args_p (const aggr_i
 #define TYPE_PTRMEMFUNC_OBJECT_TYPE(NODE) \
   TYPE_METHOD_BASETYPE (TREE_TYPE (TYPE_PTRMEMFUNC_FN_TYPE (NODE)))
 
-/* These are use to manipulate the canonical RECORD_TYPE from the
-   hashed POINTER_TYPE, and can only be used on the POINTER_TYPE.  */
-#define TYPE_GET_PTRMEMFUNC_TYPE(NODE) \
-  (TYPE_LANG_SPECIFIC (NODE) ? LANG_TYPE_PTRMEM_CHECK (NODE)->record : NULL)
-#define TYPE_SET_PTRMEMFUNC_TYPE(NODE, VALUE)				\
-  do {									\
-    if (TYPE_LANG_SPECIFIC (NODE) == NULL)				\
-      {									\
-	TYPE_LANG_SPECIFIC (NODE)                                       \
-	= (struct lang_type *) ggc_internal_cleared_alloc		\
-	 (sizeof (struct lang_type_ptrmem));				\
-	TYPE_LANG_SPECIFIC (NODE)->u.ptrmem.h.is_lang_type_class = 0;	\
-      }									\
-    TYPE_LANG_SPECIFIC (NODE)->u.ptrmem.record = (VALUE);		\
-  } while (0)
+/* The canonical internal RECORD_TYPE from the POINTER_TYPE to
+   METHOD_TYPE.  */
+#define TYPE_PTRMEMFUNC_TYPE(NODE) \
+  TYPE_LANG_SLOT_1 (NODE)
 
 /* For a pointer-to-member type of the form `T X::*', this is `X'.
    For a type like `void (X::*)() const', this type is `X', not `const
Index: cp/decl.c
===================================================================
--- cp/decl.c	(revision 248821)
+++ cp/decl.c	(working copy)
@@ -9154,7 +9154,9 @@ build_ptrmemfunc_type (tree type)
      this method instead of type_hash_canon, because it only does a
      simple equality check on the list of field members.  */
 
-  if ((t = TYPE_GET_PTRMEMFUNC_TYPE (type)))
+
+  t = TYPE_PTRMEMFUNC_TYPE (type);
+  if (t)
     return t;
 
   t = make_node (RECORD_TYPE);
@@ -9178,7 +9180,7 @@ build_ptrmemfunc_type (tree type)
 
   /* Cache this pointer-to-member type so that we can find it again
      later.  */
-  TYPE_SET_PTRMEMFUNC_TYPE (type, t);
+  TYPE_PTRMEMFUNC_TYPE (type) = t;
 
   if (TYPE_STRUCTURAL_EQUALITY_P (type))
     SET_TYPE_STRUCTURAL_EQUALITY (t);
Index: cp/lex.c
===================================================================
--- cp/lex.c	(revision 248821)
+++ cp/lex.c	(working copy)
@@ -678,24 +678,19 @@ copy_decl (tree decl MEM_STAT_DECL)
 static void
 copy_lang_type (tree node)
 {
-  int size;
-  struct lang_type *lt;
-
   if (! TYPE_LANG_SPECIFIC (node))
     return;
 
-  if (TYPE_LANG_SPECIFIC (node)->u.h.is_lang_type_class)
-    size = sizeof (struct lang_type);
-  else
-    size = sizeof (struct lang_type_ptrmem);
-  lt = (struct lang_type *) ggc_internal_alloc (size);
-  memcpy (lt, TYPE_LANG_SPECIFIC (node), size);
+  struct lang_type *lt
+    = (struct lang_type *) ggc_internal_alloc (sizeof (struct lang_type));
+
+  memcpy (lt, TYPE_LANG_SPECIFIC (node), (sizeof (struct lang_type)));
   TYPE_LANG_SPECIFIC (node) = lt;
 
   if (GATHER_STATISTICS)
     {
       tree_node_counts[(int)lang_type] += 1;
-      tree_node_sizes[(int)lang_type] += size;
+      tree_node_sizes[(int)lang_type] += sizeof (struct lang_type);
     }
 }
 
@@ -720,12 +715,9 @@ maybe_add_lang_type_raw (tree t)
 	      || TREE_CODE (t) == BOUND_TEMPLATE_TEMPLATE_PARM);
   if (add)
     {
-      struct lang_type *pi
-	= (struct lang_type *) ggc_internal_cleared_alloc
-	(sizeof (struct lang_type));
-
-      TYPE_LANG_SPECIFIC (t) = pi;
-      pi->u.c.h.is_lang_type_class = 1;
+      TYPE_LANG_SPECIFIC (t)
+	= (struct lang_type *) (ggc_internal_cleared_alloc
+				(sizeof (struct lang_type)));
 
       if (GATHER_STATISTICS)
 	{
Index: objcp/objcp-decl.h
===================================================================
--- objcp/objcp-decl.h	(revision 248821)
+++ objcp/objcp-decl.h	(working copy)
@@ -62,14 +62,11 @@ extern tree objcp_end_compound_stmt (tre
 #undef TYPE_OBJC_INFO
 #define TYPE_OBJC_INFO(TYPE) LANG_TYPE_CLASS_CHECK (TYPE)->objc_info
 #undef SIZEOF_OBJC_TYPE_LANG_SPECIFIC
-#define SIZEOF_OBJC_TYPE_LANG_SPECIFIC sizeof (struct lang_type_class)
+#define SIZEOF_OBJC_TYPE_LANG_SPECIFIC sizeof (struct lang_type)
 #undef ALLOC_OBJC_TYPE_LANG_SPECIFIC
-#define ALLOC_OBJC_TYPE_LANG_SPECIFIC(NODE)				\
-  do {									\
-    TYPE_LANG_SPECIFIC (NODE) = (struct lang_type *) \
-      ggc_internal_cleared_alloc (sizeof (struct lang_type_class));	\
-    TYPE_LANG_SPECIFIC (NODE)->u.c.h.is_lang_type_class = 1;		\
-  } while (0)
+#define ALLOC_OBJC_TYPE_LANG_SPECIFIC(NODE)			\
+  (TYPE_LANG_SPECIFIC (NODE) = (struct lang_type *)		\
+   ggc_internal_cleared_alloc (SIZEOF_OBJC_TYPE_LANG_SPECIFIC))
 
 #define OBJCP_ORIGINAL_FUNCTION(name, args) 	(name)args