Add language to cooked_index_entry

This adds a new 'lang' member to cooked_index_entry.  This holds the
language of the symbol.  This is primarily useful for the new
.debug_names reader, which will not scan the CUs for languages up
front.

This also changes cooked_index_shard::add to return a non-const
pointer.  This doesn't impact the current code, but is needed for the
new reader.

gdb/dwarf2/cooked-index.c

@@ -207,7 +207,7 @@ cooked_index_entry::full_name (struct obstack *storage, bool for_main) const
     return local_name;
 
   const char *sep = nullptr;
-  switch (per_cu->lang ())
+  switch (lang)
     {
     case language_cplus:
     case language_rust:
@@ -247,11 +247,12 @@ cooked_index_entry::write_scope (struct obstack *storage,
 
 cooked_index_entry *
 cooked_index_shard::add (sect_offset die_offset, enum dwarf_tag tag,
-			 cooked_index_flag flags, const char *name,
+			 cooked_index_flag flags, enum language lang,
+			 const char *name,
 			 cooked_index_entry_ref parent_entry,
 			 dwarf2_per_cu_data *per_cu)
 {
-  cooked_index_entry *result = create (die_offset, tag, flags, name,
+  cooked_index_entry *result = create (die_offset, tag, flags, lang, name,
 				       parent_entry, per_cu);
   m_entries.push_back (result);
 
@@ -262,7 +263,7 @@ cooked_index_shard::add (sect_offset die_offset, enum dwarf_tag tag,
   else if ((flags & IS_PARENT_DEFERRED) == 0
 	   && parent_entry.resolved == nullptr
 	   && m_main == nullptr
-	   && language_may_use_plain_main (per_cu->lang ())
+	   && language_may_use_plain_main (lang)
 	   && strcmp (name, "main") == 0)
     m_main = result;
 
@@ -301,7 +302,7 @@ cooked_index_shard::handle_gnat_encoded_entry (cooked_index_entry *entry,
 	  gdb::unique_xmalloc_ptr<char> new_name
 	    = make_unique_xstrndup (name.data (), name.length ());
 	  last = create (entry->die_offset, DW_TAG_namespace,
-			 0, new_name.get (), parent,
+			 0, language_ada, new_name.get (), parent,
 			 entry->per_cu);
 	  last->canonical = last->name;
 	  m_names.push_back (std::move (new_name));
@@ -364,7 +365,7 @@ cooked_index_shard::finalize ()
       gdb_assert (entry->canonical == nullptr);
       if ((entry->flags & IS_LINKAGE) != 0)
 	entry->canonical = entry->name;
-      else if (entry->per_cu->lang () == language_ada)
+      else if (entry->lang == language_ada)
 	{
 	  gdb::unique_xmalloc_ptr<char> canon_name
 	    = handle_gnat_encoded_entry (entry, gnat_entries.get ());
@@ -376,15 +377,14 @@ cooked_index_shard::finalize ()
 	      m_names.push_back (std::move (canon_name));
 	    }
 	}
-      else if (entry->per_cu->lang () == language_cplus
+      else if (entry->lang == language_cplus || entry->lang == language_c)
-	       || entry->per_cu->lang () == language_c)
 	{
 	  void **slot = htab_find_slot (seen_names.get (), entry,
 					INSERT);
 	  if (*slot == nullptr)
 	    {
 	      gdb::unique_xmalloc_ptr<char> canon_name
-		= (entry->per_cu->lang () == language_cplus
+		= (entry->lang == language_cplus
 		   ? cp_canonicalize_string (entry->name)
 		   : c_canonicalize_name (entry->name));
 	      if (canon_name == nullptr)
@@ -572,7 +572,7 @@ cooked_index::get_main_name (struct obstack *obstack, enum language *lang)
   if (entry == nullptr)
     return nullptr;
 
-  *lang = entry->per_cu->lang ();
+  *lang = entry->lang;
   return entry->full_name (obstack, true);
 }
 
@@ -595,7 +595,7 @@ cooked_index::get_main () const
 	{
 	  if ((entry->flags & IS_MAIN) != 0)
 	    {
-	      if (!language_requires_canonicalization (entry->per_cu->lang ()))
+	      if (!language_requires_canonicalization (entry->lang))
 		{
 		  /* There won't be one better than this.  */
 		  return entry;

gdb/dwarf2/cooked-index.h

@@ -107,12 +107,14 @@ extern bool language_requires_canonicalization (enum language lang);
 struct cooked_index_entry : public allocate_on_obstack
 {
   cooked_index_entry (sect_offset die_offset_, enum dwarf_tag tag_,
-		      cooked_index_flag flags_, const char *name_,
+		      cooked_index_flag flags_,
+		      enum language lang_, const char *name_,
 		      cooked_index_entry_ref parent_entry_,
 		      dwarf2_per_cu_data *per_cu_)
     : name (name_),
       tag (tag_),
       flags (flags_),
+      lang (lang_),
       die_offset (die_offset_),
       per_cu (per_cu_),
       m_parent_entry (parent_entry_)
@@ -281,6 +283,8 @@ struct cooked_index_entry : public allocate_on_obstack
   enum dwarf_tag tag;
   /* Any flags attached to this entry.  */
   cooked_index_flag flags;
+  /* The language of this symbol.  */
+  ENUM_BITFIELD (language) lang : LANGUAGE_BITS;
   /* The offset of this DIE.  */
   sect_offset die_offset;
   /* The CU from which this entry originates.  */
@@ -318,7 +322,7 @@ public:
   /* Create a new cooked_index_entry and register it with this object.
      Entries are owned by this object.  The new item is returned.  */
   cooked_index_entry *add (sect_offset die_offset, enum dwarf_tag tag,
-			   cooked_index_flag flags,
+			   cooked_index_flag flags, enum language lang,
 			   const char *name,
 			   cooked_index_entry_ref parent_entry,
 			   dwarf2_per_cu_data *per_cu);
@@ -370,12 +374,13 @@ private:
   cooked_index_entry *create (sect_offset die_offset,
 			      enum dwarf_tag tag,
 			      cooked_index_flag flags,
+			      enum language lang,
 			      const char *name,
 			      cooked_index_entry_ref parent_entry,
 			      dwarf2_per_cu_data *per_cu)
   {
     return new (&m_storage) cooked_index_entry (die_offset, tag, flags,
-						name, parent_entry,
+						lang, name, parent_entry,
 						per_cu);
   }
 
@@ -439,7 +444,8 @@ public:
 			   cooked_index_entry_ref parent_entry,
 			   dwarf2_per_cu_data *per_cu)
   {
-    return m_index->add (die_offset, tag, flags, name, parent_entry, per_cu);
+    return m_index->add (die_offset, tag, flags, per_cu->lang (),
+			 name, parent_entry, per_cu);
   }
 
   /* Install the current addrmap into the shard being constructed,

gdb/dwarf2/index-write.c

@@ -1282,7 +1282,7 @@ write_cooked_index (cooked_index *table,
 
       const char *name = entry->full_name (symtab->obstack ());
 
-      if (entry->per_cu->lang () == language_ada)
+      if (entry->lang == language_ada)
 	{
 	  /* In order for the index to work when read back into
 	     gdb, it has to use the encoded name, with any
@@ -1290,7 +1290,7 @@ write_cooked_index (cooked_index *table,
 	  std::string encoded = ada_encode (name, false);
 	  name = obstack_strdup (symtab->obstack (), encoded.c_str ());
 	}
-      else if (entry->per_cu->lang () == language_cplus
+      else if (entry->lang == language_cplus
 	       && (entry->flags & IS_LINKAGE) != 0)
 	{
 	  /* GDB never put C++ linkage names into .gdb_index.  The