Remove hashtab_obstack_allocate

I think that hashtabs should never be obstack-allocated.  In the past
this was convenient sometimes, because any new data structure needed a
corresponding cleanup.  However, with the switch to C++, resource
management has become much simpler; for example, a local variable can
simply be of type htab_up rather than hashtab_t, and the problem is
solved.

This patch removes hashtab_obstack_allocate to try to prevent this
anti-pattern from being used again.

gdbsupport/Makefile.am

@@ -68,7 +68,6 @@ libgdbsupport_a_SOURCES = \
     filestuff.cc \
     format.cc \
     gdb-dlfcn.cc \
-    gdb-hashtab.cc \
     gdb_obstack.cc \
     gdb_regex.cc \
     gdb_tilde_expand.cc \

gdbsupport/Makefile.in

@@ -159,8 +159,7 @@ am_libgdbsupport_a_OBJECTS = agent.$(OBJEXT) btrace-common.$(OBJEXT) \
 	common-regcache.$(OBJEXT) common-utils.$(OBJEXT) \
 	environ.$(OBJEXT) errors.$(OBJEXT) event-loop.$(OBJEXT) \
 	fileio.$(OBJEXT) filestuff.$(OBJEXT) format.$(OBJEXT) \
-	gdb-dlfcn.$(OBJEXT) gdb-hashtab.$(OBJEXT) \
+	gdb-dlfcn.$(OBJEXT) gdb_obstack.$(OBJEXT) gdb_regex.$(OBJEXT) \
-	gdb_obstack.$(OBJEXT) gdb_regex.$(OBJEXT) \
 	gdb_tilde_expand.$(OBJEXT) gdb_wait.$(OBJEXT) \
 	gdb_vecs.$(OBJEXT) job-control.$(OBJEXT) netstuff.$(OBJEXT) \
 	new-op.$(OBJEXT) pathstuff.$(OBJEXT) print-utils.$(OBJEXT) \
@@ -426,7 +425,6 @@ libgdbsupport_a_SOURCES = \
     filestuff.cc \
     format.cc \
     gdb-dlfcn.cc \
-    gdb-hashtab.cc \
     gdb_obstack.cc \
     gdb_regex.cc \
     gdb_tilde_expand.cc \
@@ -536,7 +534,6 @@ distclean-compile:
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/filestuff.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/format.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/gdb-dlfcn.Po@am__quote@
-@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/gdb-hashtab.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/gdb_obstack.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/gdb_regex.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/gdb_tilde_expand.Po@am__quote@

gdbsupport/gdb-hashtab.cc

@@ -1,43 +0,0 @@
-/* Hash table wrappers for gdb.
-   Copyright (C) 2021-2024 Free Software Foundation, Inc.
-
-   This file is part of GDB.
-
-   This program is free software; you can redistribute it and/or modify
-   it under the terms of the GNU General Public License as published by
-   the Free Software Foundation; either version 3 of the License, or
-   (at your option) any later version.
-
-   This program is distributed in the hope that it will be useful,
-   but WITHOUT ANY WARRANTY; without even the implied warranty of
-   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-   GNU General Public License for more details.
-
-   You should have received a copy of the GNU General Public License
-   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
-
-#include "gdb-hashtab.h"
-
-/* Allocation function for the libiberty hash table which uses an
-   obstack.  The obstack is passed as DATA.  */
-
-void *
-hashtab_obstack_allocate (void *data, size_t size, size_t count)
-{
-  size_t total = size * count;
-  void *ptr = obstack_alloc ((struct obstack *) data, total);
-
-  memset (ptr, 0, total);
-  return ptr;
-}
-
-/* Trivial deallocation function for the libiberty splay tree and hash
-   table - don't deallocate anything.  Rely on later deletion of the
-   obstack.  DATA will be the obstack, although it is not needed
-   here.  */
-
-void
-dummy_obstack_deallocate (void *object, void *data)
-{
-  return;
-}

gdbsupport/gdb-hashtab.h

@@ -42,9 +42,4 @@ htab_delete_entry (void *ptr)
   delete (T *) ptr;
 }
 
-/* Allocation and deallocation functions for the libiberty hash table
-   which use obstacks.  */
-void *hashtab_obstack_allocate (void *data, size_t size, size_t count);
-void dummy_obstack_deallocate (void *object, void *data);
-
 #endif /* GDBSUPPORT_GDB_HASHTAB_H */