[gcc r11-4455] c++: Kill nested_udts

Nathan Sidwell nathan@gcc.gnu.org
Tue Oct 27 17:07:45 GMT 2020


https://gcc.gnu.org/g:54380d42e6fb8da702fc57264700c81183145d39

commit r11-4455-g54380d42e6fb8da702fc57264700c81183145d39
Author: Nathan Sidwell <nathan@acm.org>
Date:   Tue Oct 27 09:59:15 2020 -0700

    c++: Kill nested_udts
    
    During the implementation of modules I added myself a note to
    implement nested_udt handling.  It wasn't obvious to me what they were
    for and nothing seemed to be broken in ignoring them.  I figured
    something would eventually pop up and I'd add support.  Nothing popped up.
    
    Investigating on trunk discovered 3 places where we look at the
    nested-udts.  I couldn't figure how the one in lookup_field_r was
    needed -- surely the regular lookup would find the type.  It turned
    out that code was unreachable.  So we can delete it.
    
    Next in do_type_instantiation, we walk the nested-utd table
    instantiating types.  But those types are also on the TYPE_FIELDS
    list, which we've just iterated over.  So I can move the handling into
    that loop.
    
    The final use is in handling structs that have a typedef name for
    linkage purposes.  Again, we can just iterate over TYPE_FIELDS.  (As
    commented, we probably don't need to do even that, as a DR, whose
    number I forget, requires such structs to only have C-like things in
    them.  But I didn't go that far.
    
    Having removed all the uses of nested-udts, I can remove their
    creation from name-lookup, and as the only instance of a binding_table
    object, we can remove all that code too.
    
            gcc/cp/
            * cp-tree.h (struct lang_type): Delete nested_udts field.
            (CLASSTYPE_NESTED_UTDS): Delete.
            * name-lookup.h (binding_table, binding_entry): Delete typedefs.
            (bt_foreach_proc): Likewise.
            (struct binding_entry_s): Delete.
            (SCOPE_DEFAULT_HT_SIZE, CLASS_SCOPE_HT_SIZE)
            (NAMESPACE_ORDINARY_HT_SIZE, NAMESPACE_STD_HT_SIZE)
            (GLOBAL_SCOPE_HT_SIZE): Delete.
            (binding_table_foreach, binding_table_find): Delete declarations.
            * name-lookup.c (ENTRY_INDEX): Delete.
            (free_binding_entry): Delete.
            (binding_entry_make, binding_entry_free): Delete.
            (struct binding_table_s): Delete.
            (binding_table_construct, binding_table_free): Delete.
            (binding_table_new, binding_table_expand): Delete.
            (binding_table_insert, binding_table_find): Delete.
            (binding_table_foreach): Delete.
            (maybe_process_template_type_declaration): Delete
            CLASSTYPE_NESTED_UTDS insertion.
            (do_pushtag): Likewise.
            * decl2.c (bt_reset_linkage_1): Fold into reset_type_linkage_1.
            (reset_type_linkage_2, bt_reset_linkage_2): Fold into
            reset_type_linkage.
            * pt.c (instantiate_class_template_1): Delete NESTED_UTDs comment.
            (bt_instantiate_type_proc): Delete.
            (do_type_instantiation): Instantiate implicit typedef fields.
            Delete NESTED_UTD walk.
            * search.c (lookup_field_r): Delete unreachable NESTED_UTD
            search.

Diff:
---
 gcc/cp/cp-tree.h     |   7 --
 gcc/cp/decl2.c       |  36 +++------
 gcc/cp/name-lookup.c | 214 +--------------------------------------------------
 gcc/cp/name-lookup.h |  23 ------
 gcc/cp/pt.c          |  32 +++-----
 gcc/cp/search.c      |  11 ---
 6 files changed, 25 insertions(+), 298 deletions(-)

diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index 1ce20989e13..4f9038eb201 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -2219,7 +2219,6 @@ struct GTY(()) lang_type {
   tree vtables;
   tree typeinfo_var;
   vec<tree, va_gc> *vbases;
-  binding_table nested_udts;
   tree as_base;
   vec<tree, va_gc> *pure_virtuals;
   tree friend_classes;
@@ -2372,12 +2371,6 @@ struct GTY(()) lang_type {
 #define CLASSTYPE_DESTRUCTOR(NODE) \
   (get_class_binding_direct (NODE, dtor_identifier))
 
-/* A dictionary of the nested user-defined-types (class-types, or enums)
-   found within this class.  This table includes nested member class
-   templates.  */
-#define CLASSTYPE_NESTED_UTDS(NODE) \
-   (LANG_TYPE_CLASS_CHECK (NODE)->nested_udts)
-
 /* Nonzero if NODE has a primary base class, i.e., a base class with
    which it shares the virtual function table pointer.  */
 #define CLASSTYPE_HAS_PRIMARY_BASE_P(NODE) \
diff --git a/gcc/cp/decl2.c b/gcc/cp/decl2.c
index 2f0d6370146..6fd081463f7 100644
--- a/gcc/cp/decl2.c
+++ b/gcc/cp/decl2.c
@@ -2894,9 +2894,8 @@ constrain_class_visibility (tree type)
 /* Functions for adjusting the visibility of a tagged type and its nested
    types and declarations when it gets a name for linkage purposes from a
    typedef.  */
-
-static void bt_reset_linkage_1 (binding_entry, void *);
-static void bt_reset_linkage_2 (binding_entry, void *);
+// FIXME: It is now a DR for such a class type to contain anything
+// other than C.  So at minium most of this can probably be deleted.
 
 /* First reset the visibility of all the types.  */
 
@@ -2905,13 +2904,9 @@ reset_type_linkage_1 (tree type)
 {
   set_linkage_according_to_type (type, TYPE_MAIN_DECL (type));
   if (CLASS_TYPE_P (type))
-    binding_table_foreach (CLASSTYPE_NESTED_UTDS (type),
-			   bt_reset_linkage_1, NULL);
-}
-static void
-bt_reset_linkage_1 (binding_entry b, void */*data*/)
-{
-  reset_type_linkage_1 (b->type);
+    for (tree member = TYPE_FIELDS (type); member; member = DECL_CHAIN (member))
+      if (DECL_IMPLICIT_TYPEDEF_P (member))
+	reset_type_linkage_1 (TREE_TYPE (member));
 }
 
 /* Then reset the visibility of any static data members or member
@@ -2930,9 +2925,10 @@ reset_decl_linkage (tree decl)
   tentative_decl_linkage (decl);
 }
 
-static void
-reset_type_linkage_2 (tree type)
+void
+reset_type_linkage (tree type)
 {
+  reset_type_linkage_1 (type);
   if (CLASS_TYPE_P (type))
     {
       if (tree vt = CLASSTYPE_VTABLES (type))
@@ -2955,24 +2951,12 @@ reset_type_linkage_2 (tree type)
 	  tree mem = STRIP_TEMPLATE (m);
 	  if (TREE_CODE (mem) == VAR_DECL || TREE_CODE (mem) == FUNCTION_DECL)
 	    reset_decl_linkage (mem);
+	  else if (DECL_IMPLICIT_TYPEDEF_P (mem))
+	    reset_type_linkage (TREE_TYPE (mem));
 	}
-      binding_table_foreach (CLASSTYPE_NESTED_UTDS (type),
-			     bt_reset_linkage_2, NULL);
     }
 }
 
-static void
-bt_reset_linkage_2 (binding_entry b, void */*data*/)
-{
-  reset_type_linkage_2 (b->type);
-}
-void
-reset_type_linkage (tree type)
-{
-  reset_type_linkage_1 (type);
-  reset_type_linkage_2 (type);
-}
-
 /* Set up our initial idea of what the linkage of DECL should be.  */
 
 void
diff --git a/gcc/cp/name-lookup.c b/gcc/cp/name-lookup.c
index 46374278068..6a88e68c346 100644
--- a/gcc/cp/name-lookup.c
+++ b/gcc/cp/name-lookup.c
@@ -1738,16 +1738,6 @@ insert_late_enum_def_bindings (tree klass, tree enumtype)
     }
 }
 
-/* Compute the chain index of a binding_entry given the HASH value of its
-   name and the total COUNT of chains.  COUNT is assumed to be a power
-   of 2.  */
-
-#define ENTRY_INDEX(HASH, COUNT) (((HASH) >> 3) & ((COUNT) - 1))
-
-/* A free list of "binding_entry"s awaiting for re-use.  */
-
-static GTY((deletable)) binding_entry free_binding_entry = NULL;
-
 /* The binding oracle; see cp-tree.h.  */
 
 cp_binding_oracle_function *cp_binding_oracle;
@@ -1770,180 +1760,6 @@ query_oracle (tree name)
   cp_binding_oracle (CP_ORACLE_IDENTIFIER, name);
 }
 
-/* Create a binding_entry object for (NAME, TYPE).  */
-
-static inline binding_entry
-binding_entry_make (tree name, tree type)
-{
-  binding_entry entry;
-
-  if (free_binding_entry)
-    {
-      entry = free_binding_entry;
-      free_binding_entry = entry->chain;
-    }
-  else
-    entry = ggc_alloc<binding_entry_s> ();
-
-  entry->name = name;
-  entry->type = type;
-  entry->chain = NULL;
-
-  return entry;
-}
-
-/* Put ENTRY back on the free list.  */
-#if 0
-static inline void
-binding_entry_free (binding_entry entry)
-{
-  entry->name = NULL;
-  entry->type = NULL;
-  entry->chain = free_binding_entry;
-  free_binding_entry = entry;
-}
-#endif
-
-/* The datatype used to implement the mapping from names to types at
-   a given scope.  */
-struct GTY(()) binding_table_s {
-  /* Array of chains of "binding_entry"s  */
-  binding_entry * GTY((length ("%h.chain_count"))) chain;
-
-  /* The number of chains in this table.  This is the length of the
-     member "chain" considered as an array.  */
-  size_t chain_count;
-
-  /* Number of "binding_entry"s in this table.  */
-  size_t entry_count;
-};
-
-/* Construct TABLE with an initial CHAIN_COUNT.  */
-
-static inline void
-binding_table_construct (binding_table table, size_t chain_count)
-{
-  table->chain_count = chain_count;
-  table->entry_count = 0;
-  table->chain = ggc_cleared_vec_alloc<binding_entry> (table->chain_count);
-}
-
-/* Make TABLE's entries ready for reuse.  */
-#if 0
-static void
-binding_table_free (binding_table table)
-{
-  size_t i;
-  size_t count;
-
-  if (table == NULL)
-    return;
-
-  for (i = 0, count = table->chain_count; i < count; ++i)
-    {
-      binding_entry temp = table->chain[i];
-      while (temp != NULL)
-	{
-	  binding_entry entry = temp;
-	  temp = entry->chain;
-	  binding_entry_free (entry);
-	}
-      table->chain[i] = NULL;
-    }
-  table->entry_count = 0;
-}
-#endif
-
-/* Allocate a table with CHAIN_COUNT, assumed to be a power of two.  */
-
-static inline binding_table
-binding_table_new (size_t chain_count)
-{
-  binding_table table = ggc_alloc<binding_table_s> ();
-  table->chain = NULL;
-  binding_table_construct (table, chain_count);
-  return table;
-}
-
-/* Expand TABLE to twice its current chain_count.  */
-
-static void
-binding_table_expand (binding_table table)
-{
-  const size_t old_chain_count = table->chain_count;
-  const size_t old_entry_count = table->entry_count;
-  const size_t new_chain_count = 2 * old_chain_count;
-  binding_entry *old_chains = table->chain;
-  size_t i;
-
-  binding_table_construct (table, new_chain_count);
-  for (i = 0; i < old_chain_count; ++i)
-    {
-      binding_entry entry = old_chains[i];
-      for (; entry != NULL; entry = old_chains[i])
-	{
-	  const unsigned int hash = IDENTIFIER_HASH_VALUE (entry->name);
-	  const size_t j = ENTRY_INDEX (hash, new_chain_count);
-
-	  old_chains[i] = entry->chain;
-	  entry->chain = table->chain[j];
-	  table->chain[j] = entry;
-	}
-    }
-  table->entry_count = old_entry_count;
-}
-
-/* Insert a binding for NAME to TYPE into TABLE.  */
-
-static void
-binding_table_insert (binding_table table, tree name, tree type)
-{
-  const unsigned int hash = IDENTIFIER_HASH_VALUE (name);
-  const size_t i = ENTRY_INDEX (hash, table->chain_count);
-  binding_entry entry = binding_entry_make (name, type);
-
-  entry->chain = table->chain[i];
-  table->chain[i] = entry;
-  ++table->entry_count;
-
-  if (3 * table->chain_count < 5 * table->entry_count)
-    binding_table_expand (table);
-}
-
-/* Return the binding_entry, if any, that maps NAME.  */
-
-binding_entry
-binding_table_find (binding_table table, tree name)
-{
-  const unsigned int hash = IDENTIFIER_HASH_VALUE (name);
-  binding_entry entry = table->chain[ENTRY_INDEX (hash, table->chain_count)];
-
-  while (entry != NULL && entry->name != name)
-    entry = entry->chain;
-
-  return entry;
-}
-
-/* Apply PROC -- with DATA -- to all entries in TABLE.  */
-
-void
-binding_table_foreach (binding_table table, bt_foreach_proc proc, void *data)
-{
-  size_t chain_count;
-  size_t i;
-
-  if (!table)
-    return;
-
-  chain_count = table->chain_count;
-  for (i = 0; i < chain_count; ++i)
-    {
-      binding_entry entry = table->chain[i];
-      for (; entry != NULL; entry = entry->chain)
-	proc (entry, data);
-    }
-}
-
 #ifndef ENABLE_SCOPE_CHECKING
 #  define ENABLE_SCOPE_CHECKING 0
 #else
@@ -6884,10 +6700,6 @@ maybe_process_template_type_declaration (tree type, int is_friend,
 
       if (processing_template_decl)
 	{
-	  /* This may change after the call to push_template_decl, but
-	     we want the original value.  */
-	  tree name = DECL_NAME (decl);
-
 	  decl = push_template_decl (decl, is_friend);
 	  if (decl == error_mark_node)
 	    return error_mark_node;
@@ -6906,17 +6718,8 @@ maybe_process_template_type_declaration (tree type, int is_friend,
 	      finish_member_declaration (CLASSTYPE_TI_TEMPLATE (type));
 
 	      if (!COMPLETE_TYPE_P (current_class_type))
-		{
-		  maybe_add_class_template_decl_list (current_class_type,
-						      type, /*friend_p=*/0);
-		  /* Put this UTD in the table of UTDs for the class.  */
-		  if (CLASSTYPE_NESTED_UTDS (current_class_type) == NULL)
-		    CLASSTYPE_NESTED_UTDS (current_class_type) =
-		      binding_table_new (SCOPE_DEFAULT_HT_SIZE);
-
-		  binding_table_insert
-		    (CLASSTYPE_NESTED_UTDS (current_class_type), name, type);
-		}
+		maybe_add_class_template_decl_list (current_class_type,
+						    type, /*friend_p=*/0);
 	    }
 	}
     }
@@ -7077,17 +6880,8 @@ do_pushtag (tree name, tree type, TAG_how how)
 
   if (b->kind == sk_class
       && !COMPLETE_TYPE_P (current_class_type))
-    {
-      maybe_add_class_template_decl_list (current_class_type,
-					  type, /*friend_p=*/0);
-
-      if (CLASSTYPE_NESTED_UTDS (current_class_type) == NULL)
-	CLASSTYPE_NESTED_UTDS (current_class_type)
-	  = binding_table_new (SCOPE_DEFAULT_HT_SIZE);
-
-      binding_table_insert
-	(CLASSTYPE_NESTED_UTDS (current_class_type), name, type);
-    }
+    maybe_add_class_template_decl_list (current_class_type,
+					type, /*friend_p=*/0);
 
   decl = TYPE_NAME (type);
   gcc_assert (TREE_CODE (decl) == TYPE_DECL);
diff --git a/gcc/cp/name-lookup.h b/gcc/cp/name-lookup.h
index d63ff108df5..6d18539e730 100644
--- a/gcc/cp/name-lookup.h
+++ b/gcc/cp/name-lookup.h
@@ -23,29 +23,6 @@ along with GCC; see the file COPYING3.  If not see
 
 #include "c-family/c-common.h"
 
-/* The type of dictionary used to map names to types declared at
-   a given scope.  */
-typedef struct binding_table_s *binding_table;
-typedef struct binding_entry_s *binding_entry;
-
-/* The type of a routine repeatedly called by binding_table_foreach.  */
-typedef void (*bt_foreach_proc) (binding_entry, void *);
-
-struct GTY(()) binding_entry_s {
-  binding_entry chain;
-  tree name;
-  tree type;
-};
-
-/* These macros indicate the initial chains count for binding_table.  */
-#define SCOPE_DEFAULT_HT_SIZE		(1 << 3)
-#define CLASS_SCOPE_HT_SIZE		(1 << 3)
-#define NAMESPACE_ORDINARY_HT_SIZE	(1 << 5)
-#define NAMESPACE_STD_HT_SIZE		(1 << 8)
-#define GLOBAL_SCOPE_HT_SIZE		(1 << 8)
-
-extern void binding_table_foreach (binding_table, bt_foreach_proc, void *);
-extern binding_entry binding_table_find (binding_table, tree);
 
 /* The datatype used to implement C++ scope.  */
 struct cp_binding_level;
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index 701f7c190fe..7e401e1cb8a 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -11851,7 +11851,6 @@ instantiate_class_template_1 (tree type)
 		   Ignore it; it will be regenerated when needed.  */
 		continue;
 
-	      /* Build new CLASSTYPE_NESTED_UTDS.  */
 	      bool class_template_p = (TREE_CODE (t) != ENUMERAL_TYPE
 				       && TYPE_LANG_SPECIFIC (t)
 				       && CLASSTYPE_IS_TEMPLATE (t));
@@ -12009,10 +12008,10 @@ instantiate_class_template_1 (tree type)
 			    TREE_TYPE (r) = error_mark_node;
 			}
 
-		      /* If it is a TYPE_DECL for a class-scoped ENUMERAL_TYPE,
-			 such a thing will already have been added to the field
-			 list by tsubst_enum in finish_member_declaration in the
-			 CLASSTYPE_NESTED_UTDS case above.  */
+		      /* If it is a TYPE_DECL for a class-scoped
+			 ENUMERAL_TYPE, such a thing will already have
+			 been added to the field list by tsubst_enum
+			 in finish_member_declaration case above.  */
 		      if (!(TREE_CODE (r) == TYPE_DECL
 			    && TREE_CODE (TREE_TYPE (r)) == ENUMERAL_TYPE
 			    && DECL_ARTIFICIAL (r)))
@@ -24959,19 +24958,6 @@ mark_class_instantiated (tree t, int extern_p)
     }
 }
 
-/* Called from do_type_instantiation through binding_table_foreach to
-   do recursive instantiation for the type bound in ENTRY.  */
-static void
-bt_instantiate_type_proc (binding_entry entry, void *data)
-{
-  tree storage = tree (data);
-
-  if (CLASS_TYPE_P (entry->type)
-      && CLASSTYPE_TEMPLATE_INFO (entry->type)
-      && !uses_template_parms (CLASSTYPE_TI_ARGS (entry->type)))
-    do_type_instantiation (entry->type, storage, 0);
-}
-
 /* Perform an explicit instantiation of template class T.  STORAGE, if
    non-null, is the RID for extern, inline or static.  COMPLAIN is
    nonzero if this is called from the parser, zero if called recursively,
@@ -25095,10 +25081,14 @@ do_type_instantiation (tree t, tree storage, tsubst_flags_t complain)
 	  instantiate_decl (fld, /*defer_ok=*/true,
 			    /*expl_inst_class_mem_p=*/true);
       }
+    else if (DECL_IMPLICIT_TYPEDEF_P (fld))
+      {
+	tree type = TREE_TYPE (fld);
 
-  if (CLASSTYPE_NESTED_UTDS (t))
-    binding_table_foreach (CLASSTYPE_NESTED_UTDS (t),
-			   bt_instantiate_type_proc, storage);
+	if (CLASS_TYPE_P (type) && CLASSTYPE_TEMPLATE_INFO (type)
+	    && !uses_template_parms (CLASSTYPE_TI_ARGS (type)))
+	  do_type_instantiation (type, storage, 0);
+      }
 }
 
 /* Given a function DECL, which is a specialization of TMPL, modify
diff --git a/gcc/cp/search.c b/gcc/cp/search.c
index e36a8aed8f8..8a1de7c49aa 100644
--- a/gcc/cp/search.c
+++ b/gcc/cp/search.c
@@ -977,17 +977,6 @@ lookup_field_r (tree binfo, void *data)
 
   nval = get_class_binding (type, lfi->name, lfi->want_type);
 
-  /* If we're looking up a type (as with an elaborated type specifier)
-     we ignore all non-types we find.  */
-  if (lfi->want_type && nval && !DECL_DECLARES_TYPE_P (nval))
-    {
-      nval = NULL_TREE;
-      if (CLASSTYPE_NESTED_UTDS (type))
-	if (binding_entry e = binding_table_find (CLASSTYPE_NESTED_UTDS (type),
-						  lfi->name))
-	  nval = TYPE_MAIN_DECL (e->type);
-    }
-
   /* If there is no declaration with the indicated name in this type,
      then there's nothing to do.  */
   if (!nval)


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