Move gdb obstack code to gdbsupport

This moves the gdb-specific obstack code -- both extensions like
obconcat and obstack_strdup, and things like auto_obstack -- to
gdbsupport.

4 files changed, 216 insertions, 8 deletions

diff --git a/gdbsupport/Makefile.am b/gdbsupport/Makefile.am
index d8f204b824..73d4149f29 100644
--- a/gdbsupport/Makefile.am
+++ b/gdbsupport/Makefile.am
@@ -52,6 +52,7 @@ libgdbsupport_a_SOURCES = \
     filestuff.cc \
     format.cc \
     gdb-dlfcn.cc \
+    gdb_obstack.cc \
     gdb_tilde_expand.cc \
     gdb_wait.cc \
     gdb_vecs.cc \
diff --git a/gdbsupport/Makefile.in b/gdbsupport/Makefile.in
index c74e26aacd..88d3dd153d 100644
--- a/gdbsupport/Makefile.in
+++ b/gdbsupport/Makefile.in
@@ -151,14 +151,15 @@ 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.$(OBJEXT) gdb_tilde_expand.$(OBJEXT) \
-	gdb_wait.$(OBJEXT) gdb_vecs.$(OBJEXT) job-control.$(OBJEXT) \
-	netstuff.$(OBJEXT) new-op.$(OBJEXT) pathstuff.$(OBJEXT) \
-	print-utils.$(OBJEXT) ptid.$(OBJEXT) rsp-low.$(OBJEXT) \
-	run-time-clock.$(OBJEXT) safe-strerror.$(OBJEXT) \
-	scoped_mmap.$(OBJEXT) search.$(OBJEXT) signals.$(OBJEXT) \
-	signals-state-save-restore.$(OBJEXT) tdesc.$(OBJEXT) \
-	thread-pool.$(OBJEXT) xml-utils.$(OBJEXT) $(am__objects_1)
+	gdb-dlfcn.$(OBJEXT) gdb_obstack.$(OBJEXT) \
+	gdb_tilde_expand.$(OBJEXT) gdb_wait.$(OBJEXT) \
+	gdb_vecs.$(OBJEXT) job-control.$(OBJEXT) netstuff.$(OBJEXT) \
+	new-op.$(OBJEXT) pathstuff.$(OBJEXT) print-utils.$(OBJEXT) \
+	ptid.$(OBJEXT) rsp-low.$(OBJEXT) run-time-clock.$(OBJEXT) \
+	safe-strerror.$(OBJEXT) scoped_mmap.$(OBJEXT) search.$(OBJEXT) \
+	signals.$(OBJEXT) signals-state-save-restore.$(OBJEXT) \
+	tdesc.$(OBJEXT) thread-pool.$(OBJEXT) xml-utils.$(OBJEXT) \
+	$(am__objects_1)
 libgdbsupport_a_OBJECTS = $(am_libgdbsupport_a_OBJECTS)
 AM_V_P = $(am__v_P_@AM_V@)
 am__v_P_ = $(am__v_P_@AM_DEFAULT_V@)
@@ -336,6 +337,7 @@ pdfdir = @pdfdir@
 prefix = @prefix@
 program_transform_name = @program_transform_name@
 psdir = @psdir@
+runstatedir = @runstatedir@
 sbindir = @sbindir@
 sharedstatedir = @sharedstatedir@
 srcdir = @srcdir@
@@ -375,6 +377,7 @@ libgdbsupport_a_SOURCES = \
     filestuff.cc \
     format.cc \
     gdb-dlfcn.cc \
+    gdb_obstack.cc \
     gdb_tilde_expand.cc \
     gdb_wait.cc \
     gdb_vecs.cc \
@@ -480,6 +483,7 @@ distclean-compile:
 @AMDEP_TRUE@@am__include@ @am__quote@./$(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@./$(DEPDIR)/gdb_obstack.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/gdb_tilde_expand.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/gdb_vecs.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/gdb_wait.Po@am__quote@
diff --git a/gdbsupport/gdb_obstack.cc b/gdbsupport/gdb_obstack.cc
new file mode 100644
index 0000000000..571f34a7ad
--- /dev/null
+++ b/gdbsupport/gdb_obstack.cc
@@ -0,0 +1,47 @@
+/* Obstack wrapper for GDB.
+
+   Copyright (C) 2013-2022 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 "common-defs.h"
+#include "gdb_obstack.h"
+
+/* Concatenate NULL terminated variable argument list of `const char *'
+   strings; return the new string.  Space is found in the OBSTACKP.
+   Argument list must be terminated by a sentinel expression `(char *)
+   NULL'.  */
+
+char *
+obconcat (struct obstack *obstackp, ...)
+{
+  va_list ap;
+
+  va_start (ap, obstackp);
+  for (;;)
+    {
+      const char *s = va_arg (ap, const char *);
+
+      if (s == NULL)
+	break;
+
+      obstack_grow_str (obstackp, s);
+    }
+  va_end (ap);
+  obstack_1grow (obstackp, 0);
+
+  return (char *) obstack_finish (obstackp);
+}
diff --git a/gdbsupport/gdb_obstack.h b/gdbsupport/gdb_obstack.h
new file mode 100644
index 0000000000..5e870cb798
--- /dev/null
+++ b/gdbsupport/gdb_obstack.h
@@ -0,0 +1,156 @@
+/* Obstack wrapper for GDB.
+
+   Copyright (C) 2002-2022 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/>.  */
+
+#if !defined (GDB_OBSTACK_H)
+#define GDB_OBSTACK_H 1
+
+#include "obstack.h"
+
+/* Utility macros - wrap obstack alloc into something more robust.  */
+
+template <typename T>
+static inline T*
+obstack_zalloc (struct obstack *ob)
+{
+  static_assert (IsMallocable<T>::value, "Trying to use OBSTACK_ZALLOC with a \
+non-POD data type.  Use obstack_new instead.");
+  return ((T *) memset (obstack_alloc (ob, sizeof (T)), 0, sizeof (T)));
+}
+
+#define OBSTACK_ZALLOC(OBSTACK,TYPE) obstack_zalloc<TYPE> ((OBSTACK))
+
+template <typename T>
+static inline T *
+obstack_calloc (struct obstack *ob, size_t number)
+{
+  static_assert (IsMallocable<T>::value, "Trying to use OBSTACK_CALLOC with a \
+non-POD data type.  Use obstack_new instead.");
+  return ((T *) memset (obstack_alloc (ob, number * sizeof (T)), 0,
+			number * sizeof (T)));
+}
+
+#define OBSTACK_CALLOC(OBSTACK,NUMBER,TYPE) \
+  obstack_calloc<TYPE> ((OBSTACK), (NUMBER))
+
+/* Allocate an object on OB and call its constructor.  */
+
+template <typename T, typename... Args>
+static inline T*
+obstack_new (struct obstack *ob, Args&&... args)
+{
+  T* object = (T *) obstack_alloc (ob, sizeof (T));
+  object = new (object) T (std::forward<Args> (args)...);
+  return object;
+}
+
+/* Unless explicitly specified, GDB obstacks always use xmalloc() and
+   xfree().  */
+/* Note: ezannoni 2004-02-09: One could also specify the allocation
+   functions using a special init function for each obstack,
+   obstack_specify_allocation.  However we just use obstack_init and
+   let these defines here do the job.  While one could argue the
+   superiority of one approach over the other, we just chose one
+   throughout.  */
+
+#define obstack_chunk_alloc xmalloc
+#define obstack_chunk_free xfree
+
+#define obstack_grow_str(OBSTACK,STRING) \
+  obstack_grow (OBSTACK, STRING, strlen (STRING))
+#define obstack_grow_str0(OBSTACK,STRING) \
+  obstack_grow0 (OBSTACK, STRING, strlen (STRING))
+
+#define obstack_grow_wstr(OBSTACK, WSTRING) \
+  obstack_grow (OBSTACK, WSTRING, sizeof (gdb_wchar_t) * gdb_wcslen (WSTRING))
+
+/* Concatenate NULL terminated variable argument list of `const char
+   *' strings; return the new string.  Space is found in the OBSTACKP.
+   Argument list must be terminated by a sentinel expression `(char *)
+   NULL'.  */
+
+extern char *obconcat (struct obstack *obstackp, ...) ATTRIBUTE_SENTINEL;
+
+/* Duplicate STRING, returning an equivalent string that's allocated on the
+   obstack OBSTACKP.  */
+
+static inline char *
+obstack_strdup (struct obstack *obstackp, const char *string)
+{
+  return (char *) obstack_copy0 (obstackp, string, strlen (string));
+}
+
+/* Duplicate STRING, returning an equivalent string that's allocated on the
+   obstack OBSTACKP.  */
+
+static inline char *
+obstack_strdup (struct obstack *obstackp, const std::string &string)
+{
+  return (char *) obstack_copy0 (obstackp, string.c_str (),
+				 string.size ());
+}
+
+/* Duplicate the first N characters of STRING, returning a
+   \0-terminated string that's allocated on the obstack OBSTACKP.
+   Note that exactly N characters are copied, even if STRING is
+   shorter.  */
+
+static inline char *
+obstack_strndup (struct obstack *obstackp, const char *string, size_t n)
+{
+  return (char *) obstack_copy0 (obstackp, string, n);
+}
+
+/* An obstack that frees itself on scope exit.  */
+struct auto_obstack : obstack
+{
+  auto_obstack ()
+  { obstack_init (this); }
+
+  ~auto_obstack ()
+  { obstack_free (this, NULL); }
+
+  DISABLE_COPY_AND_ASSIGN (auto_obstack);
+
+  /* Free all memory in the obstack but leave it valid for further
+     allocation.  */
+  void clear ()
+  { obstack_free (this, obstack_base (this)); }
+};
+
+/* Objects are allocated on obstack instead of heap.  */
+
+struct allocate_on_obstack
+{
+  allocate_on_obstack () = default;
+
+  void* operator new (size_t size, struct obstack *obstack)
+  {
+    return obstack_alloc (obstack, size);
+  }
+
+  void* operator new[] (size_t size, struct obstack *obstack)
+  {
+    return obstack_alloc (obstack, size);
+  }
+
+  void operator delete (void *memory) {}
+  void operator delete[] (void *memory) {}
+};
+
+#endif