This introduces a thread-state object and moves various C globals

there.  It also introduces #defines for these globals to avoid a
monster patch.

The #defines mean that this patch also has to rename a few fields
whose names clash with the defines.

There is currently just a single "thread"; so this patch does not
impact Emacs behavior in any significant way.

14 files changed, 223 insertions, 101 deletions

diff --git a/src/Makefile.in b/src/Makefile.in
index 4b1520ada62..2d1bdd097ef 100644
--- a/src/Makefile.in
+++ b/src/Makefile.in
@@ -336,7 +336,7 @@ base_obj = dispnew.o frame.o scroll.o xdisp.o menu.o $(XMENU_OBJ) window.o \
         eval.o floatfns.o fns.o font.o print.o lread.o \
         syntax.o $(UNEXEC_OBJ) bytecode.o \
         process.o gnutls.o callproc.o \
-        region-cache.o sound.o atimer.o \
+        region-cache.o sound.o atimer.o thread.o \
         doprnt.o intervals.o textprop.o composite.o xml.o \
         $(MSDOS_OBJ) $(MSDOS_X_OBJ) $(NS_OBJ) $(CYGWIN_OBJ) $(FONT_OBJ)
 obj = $(base_obj) $(NS_OBJC_OBJ)
diff --git a/src/alloc.c b/src/alloc.c
index 1d484d4a322..bdf7b24af04 100644
--- a/src/alloc.c
+++ b/src/alloc.c
@@ -372,10 +372,6 @@ struct mem_node
   enum mem_type type;
 };
 
-/* Base address of stack.  Set in main.  */
-
-Lisp_Object *stack_base;
-
 /* Root of the tree describing allocated Lisp memory.  */
 
 static struct mem_node *mem_root;
@@ -423,10 +419,6 @@ static void check_gcpros (void);
 # define DEADP(x) 0
 #endif
 
-/* Recording what needs to be marked for gc.  */
-
-struct gcpro *gcprolist;
-
 /* Addresses of staticpro'd variables.  Initialize it to a nonzero
    value; otherwise some compilers put it into BSS.  */
 
@@ -4891,7 +4883,7 @@ mark_stack (void)
     Lisp_Object o;
     jmp_buf j;
   } j;
-  volatile int stack_grows_down_p = (char *) &j > (char *) stack_base;
+  volatile int stack_grows_down_p = (char *) &j > (char *) stack_bottom;
 #endif
   /* This trick flushes the register windows so that all the state of
      the process is contained in the stack.  */
@@ -4933,7 +4925,7 @@ mark_stack (void)
   /* This assumes that the stack is a contiguous region in memory.  If
      that's not the case, something has to be done here to iterate
      over the stack segments.  */
-  mark_memory (stack_base, end);
+  mark_memory (stack_bottom, end);
 
   /* Allow for marking a secondary stack, like the register stack on the
      ia64.  */
diff --git a/src/buffer.c b/src/buffer.c
index 56d6231f5f8..7fb1029a314 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -44,8 +44,6 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 #include "keymap.h"
 #include "frame.h"
 
-struct buffer *current_buffer;          /* the current buffer */
-
 /* First buffer in chain of all buffers (in reverse order of creation).
    Threaded through ->header.next.buffer.  */
 
diff --git a/src/buffer.h b/src/buffer.h
index 7a6bddee5ec..1c9f5d972a9 100644
--- a/src/buffer.h
+++ b/src/buffer.h
@@ -872,10 +872,6 @@ extern struct buffer *all_buffers;
 #define FOR_EACH_BUFFER(b) \
   for ((b) = all_buffers; (b); (b) = (b)->header.next.buffer)
 
-/* This points to the current buffer.  */
-
-extern struct buffer *current_buffer;
-
 /* This structure holds the default values of the buffer-local variables
    that have special slots in each buffer.
    The default value occupies the same slot in this structure
diff --git a/src/bytecode.c b/src/bytecode.c
index 5ac8b4fa2bd..019459491e9 100644
--- a/src/bytecode.c
+++ b/src/bytecode.c
@@ -328,7 +328,7 @@ struct byte_stack
    done.  Signaling an error truncates the list analogous to
    gcprolist.  */
 
-struct byte_stack *byte_stack_list;
+/* struct byte_stack *byte_stack_list; */
 
 
 /* Mark objects on byte_stack_list.  Called during GC.  */
diff --git a/src/emacs.c b/src/emacs.c
index 8d458c612cc..e1acd365e29 100644
--- a/src/emacs.c
+++ b/src/emacs.c
@@ -140,10 +140,6 @@ int running_asynch_code;
 int display_arg;
 #endif
 
-/* An address near the bottom of the stack.
-   Tells GC how to save a copy of the stack.  */
-char *stack_bottom;
-
 #if defined (DOUG_LEA_MALLOC) || defined (GNU_LINUX)
 /* The address where the heap starts (from the first sbrk (0) call).  */
 static void *my_heap_start;
@@ -687,9 +683,6 @@ void (*__malloc_initialize_hook) (void) EXTERNALLY_VISIBLE = malloc_initialize_h
 int
 main (int argc, char **argv)
 {
-#if GC_MARK_STACK
-  Lisp_Object dummy;
-#endif
   char stack_bottom_variable;
   int do_initial_setlocale;
   int skip_args = 0;
@@ -704,9 +697,8 @@ main (int argc, char **argv)
 #endif
   char *ch_to_dir;
 
-#if GC_MARK_STACK
-  stack_base = &dummy;
-#endif
+  /* Record (approximately) where the stack begins.  */
+  stack_bottom = &stack_bottom_variable;
 
 #if defined (USE_GTK) && defined (G_SLICE_ALWAYS_MALLOC)
   /* This is used by the Cygwin build.  */
@@ -852,9 +844,6 @@ main (int argc, char **argv)
     }
 #endif /* HAVE_SETRLIMIT and RLIMIT_STACK */
 
-  /* Record (approximately) where the stack begins.  */
-  stack_bottom = &stack_bottom_variable;
-
   clearerr (stdin);
 
 #ifndef SYSTEM_MALLOC
diff --git a/src/eval.c b/src/eval.c
index b531f790cc5..768cdc1a8f8 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -42,12 +42,12 @@ struct backtrace
   unsigned int debug_on_exit : 1;
 };
 
-static struct backtrace *backtrace_list;
+/* static struct backtrace *backtrace_list; */
 
-#if !BYTE_MARK_STACK
-static
-#endif
-struct catchtag *catchlist;
+/* #if !BYTE_MARK_STACK */
+/* static */
+/* #endif */
+/* struct catchtag *catchlist; */
 
 /* Chain of condition handlers currently in effect.
    The elements of this chain are contained in the stack frames
@@ -55,10 +55,10 @@ struct catchtag *catchlist;
    When an error is signaled (by calling Fsignal, below),
    this chain is searched for an element that applies.  */
 
-#if !BYTE_MARK_STACK
-static
-#endif
-struct handler *handlerlist;
+/* #if !BYTE_MARK_STACK */
+/* static */
+/* #endif */
+/* struct handler *handlerlist; */
 
 #ifdef DEBUG_GCPRO
 /* Count levels of GCPRO to detect failure to UNGCPRO.  */
@@ -90,19 +90,19 @@ Lisp_Object Vautoload_queue;
 
 /* Current number of specbindings allocated in specpdl.  */
 
-ptrdiff_t specpdl_size;
+/* ptrdiff_t specpdl_size; */
 
 /* Pointer to beginning of specpdl.  */
 
-struct specbinding *specpdl;
+/* struct specbinding *specpdl; */
 
 /* Pointer to first unused element in specpdl.  */
 
-struct specbinding *specpdl_ptr;
+/* struct specbinding *specpdl_ptr; */
 
 /* Depth in Lisp evaluations and function calls.  */
 
-static EMACS_INT lisp_eval_depth;
+/* static EMACS_INT lisp_eval_depth; */
 
 /* The value of num_nonmacro_input_events as of the last time we
    started to enter the debugger.  If we decide to enter the debugger
@@ -1051,8 +1051,8 @@ internal_catch (Lisp_Object tag, Lisp_Object (*func) (Lisp_Object), Lisp_Object
   c.tag = tag;
   c.val = Qnil;
   c.backlist = backtrace_list;
-  c.handlerlist = handlerlist;
-  c.lisp_eval_depth = lisp_eval_depth;
+  c.f_handlerlist = handlerlist;
+  c.f_lisp_eval_depth = lisp_eval_depth;
   c.pdlcount = SPECPDL_INDEX ();
   c.poll_suppress_count = poll_suppress_count;
   c.interrupt_input_blocked = interrupt_input_blocked;
@@ -1106,7 +1106,7 @@ unwind_to_catch (struct catchtag *catch, Lisp_Object value)
       /* Unwind the specpdl stack, and then restore the proper set of
          handlers.  */
       unbind_to (catchlist->pdlcount, Qnil);
-      handlerlist = catchlist->handlerlist;
+      handlerlist = catchlist->f_handlerlist;
       catchlist = catchlist->next;
     }
   while (! last_time);
@@ -1127,7 +1127,7 @@ unwind_to_catch (struct catchtag *catch, Lisp_Object value)
   gcpro_level = gcprolist ? gcprolist->level + 1 : 0;
 #endif
   backtrace_list = catch->backlist;
-  lisp_eval_depth = catch->lisp_eval_depth;
+  lisp_eval_depth = catch->f_lisp_eval_depth;
 
   _longjmp (catch->jmp, 1);
 }
@@ -1231,8 +1231,8 @@ internal_lisp_condition_case (volatile Lisp_Object var, Lisp_Object bodyform,
   c.tag = Qnil;
   c.val = Qnil;
   c.backlist = backtrace_list;
-  c.handlerlist = handlerlist;
-  c.lisp_eval_depth = lisp_eval_depth;
+  c.f_handlerlist = handlerlist;
+  c.f_lisp_eval_depth = lisp_eval_depth;
   c.pdlcount = SPECPDL_INDEX ();
   c.poll_suppress_count = poll_suppress_count;
   c.interrupt_input_blocked = interrupt_input_blocked;
@@ -1286,8 +1286,8 @@ internal_condition_case (Lisp_Object (*bfun) (void), Lisp_Object handlers,
   c.tag = Qnil;
   c.val = Qnil;
   c.backlist = backtrace_list;
-  c.handlerlist = handlerlist;
-  c.lisp_eval_depth = lisp_eval_depth;
+  c.f_handlerlist = handlerlist;
+  c.f_lisp_eval_depth = lisp_eval_depth;
   c.pdlcount = SPECPDL_INDEX ();
   c.poll_suppress_count = poll_suppress_count;
   c.interrupt_input_blocked = interrupt_input_blocked;
@@ -1324,8 +1324,8 @@ internal_condition_case_1 (Lisp_Object (*bfun) (Lisp_Object), Lisp_Object arg,
   c.tag = Qnil;
   c.val = Qnil;
   c.backlist = backtrace_list;
-  c.handlerlist = handlerlist;
-  c.lisp_eval_depth = lisp_eval_depth;
+  c.f_handlerlist = handlerlist;
+  c.f_lisp_eval_depth = lisp_eval_depth;
   c.pdlcount = SPECPDL_INDEX ();
   c.poll_suppress_count = poll_suppress_count;
   c.interrupt_input_blocked = interrupt_input_blocked;
@@ -1366,8 +1366,8 @@ internal_condition_case_2 (Lisp_Object (*bfun) (Lisp_Object, Lisp_Object),
   c.tag = Qnil;
   c.val = Qnil;
   c.backlist = backtrace_list;
-  c.handlerlist = handlerlist;
-  c.lisp_eval_depth = lisp_eval_depth;
+  c.f_handlerlist = handlerlist;
+  c.f_lisp_eval_depth = lisp_eval_depth;
   c.pdlcount = SPECPDL_INDEX ();
   c.poll_suppress_count = poll_suppress_count;
   c.interrupt_input_blocked = interrupt_input_blocked;
@@ -1410,8 +1410,8 @@ internal_condition_case_n (Lisp_Object (*bfun) (ptrdiff_t, Lisp_Object *),
   c.tag = Qnil;
   c.val = Qnil;
   c.backlist = backtrace_list;
-  c.handlerlist = handlerlist;
-  c.lisp_eval_depth = lisp_eval_depth;
+  c.f_handlerlist = handlerlist;
+  c.f_lisp_eval_depth = lisp_eval_depth;
   c.pdlcount = SPECPDL_INDEX ();
   c.poll_suppress_count = poll_suppress_count;
   c.interrupt_input_blocked = interrupt_input_blocked;
diff --git a/src/lisp.h b/src/lisp.h
index a0d47b3895e..0367d9938b7 100644
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -2015,10 +2015,6 @@ struct specbinding
     Lisp_Object unused;         /* Dividing by 16 is faster than by 12 */
   };
 
-extern struct specbinding *specpdl;
-extern struct specbinding *specpdl_ptr;
-extern ptrdiff_t specpdl_size;
-
 #define SPECPDL_INDEX() (specpdl_ptr - specpdl)
 
 /* Everything needed to describe an active condition case.  */
@@ -2071,8 +2067,8 @@ struct catchtag
   struct gcpro *gcpro;
   jmp_buf jmp;
   struct backtrace *backlist;
-  struct handler *handlerlist;
-  EMACS_INT lisp_eval_depth;
+  struct handler *f_handlerlist;
+  EMACS_INT f_lisp_eval_depth;
   ptrdiff_t pdlcount;
   int poll_suppress_count;
   int interrupt_input_blocked;
@@ -2081,10 +2077,6 @@ struct catchtag
 
 extern Lisp_Object memory_signal_data;
 
-/* An address near the bottom of the stack.
-   Tells GC how to save a copy of the stack.  */
-extern char *stack_bottom;
-
 /* Check quit-flag and quit if it is non-nil.
    Typing C-g does not directly cause a quit; it only sets Vquit_flag.
    So the program needs to do QUIT at times when it is safe to quit.
@@ -2140,8 +2132,6 @@ extern Lisp_Object Vascii_canon_table;
    Every function that can call Feval must protect in this fashion all
    Lisp_Object variables whose contents will be used again.  */
 
-extern struct gcpro *gcprolist;
-
 struct gcpro
 {
   struct gcpro *next;
@@ -2246,8 +2236,6 @@ struct gcpro
 
 #else
 
-extern int gcpro_level;
-
 #define GCPRO1(varname) \
  {gcpro1.next = gcprolist; gcpro1.var = &varname; gcpro1.nvars = 1; \
   gcpro1.level = gcpro_level++; \
@@ -2729,7 +2717,6 @@ extern void refill_memory_reserve (void);
 #endif
 extern const char *pending_malloc_warning;
 extern Lisp_Object zero_vector;
-extern Lisp_Object *stack_base;
 extern EMACS_INT consing_since_gc;
 extern EMACS_INT gc_relative_threshold;
 extern EMACS_INT memory_full_cons_threshold;
@@ -2915,10 +2902,6 @@ extern Lisp_Object Vautoload_queue;
 extern Lisp_Object Vsignaling_function;
 extern Lisp_Object inhibit_lisp_code;
 extern int handling_signal;
-#if BYTE_MARK_STACK
-extern struct catchtag *catchlist;
-extern struct handler *handlerlist;
-#endif
 /* To run a normal hook, use the appropriate function from the list below.
    The calling convention:
 
@@ -3227,7 +3210,6 @@ extern int read_bytecode_char (int);
 /* Defined in bytecode.c */
 extern Lisp_Object Qbytecode;
 extern void syms_of_bytecode (void);
-extern struct byte_stack *byte_stack_list;
 #if BYTE_MARK_STACK
 extern void mark_byte_stack (void);
 #endif
@@ -3524,6 +3506,7 @@ extern void *record_xmalloc (size_t);
 
 
 #include "globals.h"
+#include "thread.h"
 
 /* Check whether it's time for GC, and run it if so.  */
 
diff --git a/src/regex.c b/src/regex.c
index 472ef727979..b995538e30d 100644
--- a/src/regex.c
+++ b/src/regex.c
@@ -1235,12 +1235,14 @@ print_double_string (where, string1, size1, string2, size2)
 # define IF_LINT(Code) /* empty */
 #endif
 
+#ifndef emacs
 /* Set by `re_set_syntax' to the current regexp syntax to recognize.  Can
    also be assigned to arbitrarily: each pattern buffer stores its own
    syntax, so it can be changed between regex compilations.  */
 /* This has no initializer because initialized variables in Emacs
    become read-only after dumping.  */
 reg_syntax_t re_syntax_options;
+#endif
 
 
 /* Specify the precise syntax of regexps for compilation.  This provides
@@ -1260,8 +1262,10 @@ re_set_syntax (reg_syntax_t syntax)
 }
 WEAK_ALIAS (__re_set_syntax, re_set_syntax)
 
+#ifndef emacs
 /* Regexp to use to replace spaces, or NULL meaning don't.  */
 static re_char *whitespace_regexp;
+#endif
 
 void
 re_set_whitespace_regexp (const char *regexp)
@@ -4900,12 +4904,6 @@ re_match (struct re_pattern_buffer *bufp, const char *string,
 WEAK_ALIAS (__re_match, re_match)
 #endif /* not emacs */
 
-#ifdef emacs
-/* In Emacs, this is the string or buffer in which we
-   are matching.  It is used for looking up syntax properties.  */
-Lisp_Object re_match_object;
-#endif
-
 /* re_match_2 matches the compiled pattern in BUFP against the
    the (virtual) concatenation of STRING1 and STRING2 (of length SIZE1
    and SIZE2, respectively).  We start matching at POS, and stop
diff --git a/src/regex.h b/src/regex.h
index e0ede012b20..91886a80549 100644
--- a/src/regex.h
+++ b/src/regex.h
@@ -166,12 +166,12 @@ typedef unsigned long int reg_syntax_t;
    some interfaces).  When a regexp is compiled, the syntax used is
    stored in the pattern buffer, so changing this does not affect
    already-compiled regexps.  */
-extern reg_syntax_t re_syntax_options;
+/* extern reg_syntax_t re_syntax_options; */
 
 #ifdef emacs
 /* In Emacs, this is the string or buffer in which we
    are matching.  It is used for looking up syntax properties.  */
-extern Lisp_Object re_match_object;
+/* extern Lisp_Object re_match_object; */
 #endif
 
 
diff --git a/src/search.c b/src/search.c
index 004e599be9c..5df01f664f7 100644
--- a/src/search.c
+++ b/src/search.c
@@ -42,7 +42,7 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 struct regexp_cache
 {
   struct regexp_cache *next;
-  Lisp_Object regexp, whitespace_regexp;
+  Lisp_Object regexp, f_whitespace_regexp;
   /* Syntax table for which the regexp applies.  We need this because
      of character classes.  If this is t, then the compiled pattern is valid
      for any syntax-table.  */
@@ -77,12 +77,12 @@ static struct regexp_cache *searchbuf_head;
    to call re_set_registers after compiling a new pattern or after
    setting the match registers, so that the regex functions will be
    able to free or re-allocate it properly.  */
-static struct re_registers search_regs;
+/* static struct re_registers search_regs; */
 
 /* The buffer in which the last search was performed, or
    Qt if the last search was done in a string;
    Qnil if no searching has been done yet.  */
-static Lisp_Object last_thing_searched;
+/* static Lisp_Object last_thing_searched; */
 
 /* Error condition signaled when regexp compile_pattern fails.  */
 static Lisp_Object Qinvalid_regexp;
@@ -129,9 +129,9 @@ compile_pattern_1 (struct regexp_cache *cp, Lisp_Object pattern, Lisp_Object tra
   cp->buf.multibyte = STRING_MULTIBYTE (pattern);
   cp->buf.charset_unibyte = charset_unibyte;
   if (STRINGP (Vsearch_spaces_regexp))
-    cp->whitespace_regexp = Vsearch_spaces_regexp;
+    cp->f_whitespace_regexp = Vsearch_spaces_regexp;
   else
-    cp->whitespace_regexp = Qnil;
+    cp->f_whitespace_regexp = Qnil;
 
   /* rms: I think BLOCK_INPUT is not needed here any more,
      because regex.c defines malloc to call xmalloc.
@@ -230,7 +230,7 @@ compile_pattern (Lisp_Object pattern, struct re_registers *regp, Lisp_Object tra
           && cp->posix == posix
           && (EQ (cp->syntax_table, Qt)
               || EQ (cp->syntax_table, BVAR (current_buffer, syntax_table)))
-          && !NILP (Fequal (cp->whitespace_regexp, Vsearch_spaces_regexp))
+          && !NILP (Fequal (cp->f_whitespace_regexp, Vsearch_spaces_regexp))
           && cp->buf.charset_unibyte == charset_unibyte)
         break;
 
@@ -2938,9 +2938,9 @@ If optional arg RESEAT is non-nil, make markers on LIST point nowhere.  */)
 
 /* If non-zero the match data have been saved in saved_search_regs
    during the execution of a sentinel or filter. */
-static int search_regs_saved;
-static struct re_registers saved_search_regs;
-static Lisp_Object saved_last_thing_searched;
+/* static int search_regs_saved; */
+/* static struct re_registers saved_search_regs; */
+/* static Lisp_Object saved_last_thing_searched; */
 
 /* Called from Flooking_at, Fstring_match, search_buffer, Fstore_match_data
    if asynchronous code (filter or sentinel) is running. */
@@ -3044,10 +3044,10 @@ syms_of_search (void)
       searchbufs[i].buf.buffer = xmalloc (100);
       searchbufs[i].buf.fastmap = searchbufs[i].fastmap;
       searchbufs[i].regexp = Qnil;
-      searchbufs[i].whitespace_regexp = Qnil;
+      searchbufs[i].f_whitespace_regexp = Qnil;
       searchbufs[i].syntax_table = Qnil;
       staticpro (&searchbufs[i].regexp);
-      staticpro (&searchbufs[i].whitespace_regexp);
+      staticpro (&searchbufs[i].f_whitespace_regexp);
       staticpro (&searchbufs[i].syntax_table);
       searchbufs[i].next = (i == REGEXP_CACHE_SIZE-1 ? 0 : &searchbufs[i+1]);
     }
diff --git a/src/thread.c b/src/thread.c
new file mode 100644
index 00000000000..0bd97b4fd8e
--- /dev/null
+++ b/src/thread.c
@@ -0,0 +1,26 @@
+/* Threading code.
+   Copyright (C) 2012 Free Software Foundation, Inc.
+
+This file is part of GNU Emacs.
+
+GNU Emacs 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.
+
+GNU Emacs 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 GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
+
+
+#include <config.h>
+#include <setjmp.h>
+#include "lisp.h"
+
+struct thread_state the_only_thread;
+
+struct thread_state *current_thread = &the_only_thread;
diff --git a/src/thread.h b/src/thread.h
new file mode 100644
index 00000000000..b2eb04d42e8
--- /dev/null
+++ b/src/thread.h
@@ -0,0 +1,140 @@
+/* Thread definitions
+   Copyright (C) 2012 Free Software Foundation, Inc.
+
+This file is part of GNU Emacs.
+
+GNU Emacs 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.
+
+GNU Emacs 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 GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#ifndef THREAD_H
+#define THREAD_H
+
+#include "regex.h"
+
+struct thread_state
+{
+  /* The buffer in which the last search was performed, or
+     Qt if the last search was done in a string;
+     Qnil if no searching has been done yet.  */
+  Lisp_Object m_last_thing_searched;
+#define last_thing_searched (current_thread->m_last_thing_searched)
+
+  Lisp_Object m_saved_last_thing_searched;
+#define saved_last_thing_searched (current_thread->m_saved_last_thing_searched)
+
+  /* m_gcprolist must be the first non-lisp field.  */
+  /* Recording what needs to be marked for gc.  */
+  struct gcpro *m_gcprolist;
+#define gcprolist (current_thread->m_gcprolist)
+
+  /* A list of currently active byte-code execution value stacks.
+     Fbyte_code adds an entry to the head of this list before it starts
+     processing byte-code, and it removed the entry again when it is
+     done.  Signalling an error truncates the list analoguous to
+     gcprolist.  */
+  struct byte_stack *m_byte_stack_list;
+#define byte_stack_list (current_thread->m_byte_stack_list)
+
+  /* An address near the bottom of the stack.
+     Tells GC how to save a copy of the stack.  */
+  char *m_stack_bottom;
+#define stack_bottom (current_thread->m_stack_bottom)
+
+  /* An address near the top of the stack.  */
+  char *stack_top;
+
+  struct backtrace *m_backtrace_list;
+#define backtrace_list (current_thread->m_backtrace_list)
+
+  struct catchtag *m_catchlist;
+#define catchlist (current_thread->m_catchlist)
+
+  /* Chain of condition handlers currently in effect.
+     The elements of this chain are contained in the stack frames
+     of Fcondition_case and internal_condition_case.
+     When an error is signaled (by calling Fsignal, below),
+     this chain is searched for an element that applies.  */
+  struct handler *m_handlerlist;
+#define handlerlist (current_thread->m_handlerlist)
+
+  /* Count levels of GCPRO to detect failure to UNGCPRO.  */
+  int m_gcpro_level;
+#define gcpro_level (current_thread->m_gcpro_level)
+
+  /* Current number of specbindings allocated in specpdl.  */
+  ptrdiff_t m_specpdl_size;
+#define specpdl_size (current_thread->m_specpdl_size)
+
+  /* Pointer to beginning of specpdl.  */
+  struct specbinding *m_specpdl;
+#define specpdl (current_thread->m_specpdl)
+
+  /* Pointer to first unused element in specpdl.  */
+  struct specbinding *m_specpdl_ptr;
+#define specpdl_ptr (current_thread->m_specpdl_ptr)
+
+  /* Depth in Lisp evaluations and function calls.  */
+  EMACS_INT m_lisp_eval_depth;
+#define lisp_eval_depth (current_thread->m_lisp_eval_depth)
+
+  /* This points to the current buffer.  */
+  struct buffer *m_current_buffer;
+#define current_buffer (current_thread->m_current_buffer)
+
+  /* Every call to re_match, etc., must pass &search_regs as the regs
+     argument unless you can show it is unnecessary (i.e., if re_match
+     is certainly going to be called again before region-around-match
+     can be called).
+
+     Since the registers are now dynamically allocated, we need to make
+     sure not to refer to the Nth register before checking that it has
+     been allocated by checking search_regs.num_regs.
+
+     The regex code keeps track of whether it has allocated the search
+     buffer using bits in the re_pattern_buffer.  This means that whenever
+     you compile a new pattern, it completely forgets whether it has
+     allocated any registers, and will allocate new registers the next
+     time you call a searching or matching function.  Therefore, we need
+     to call re_set_registers after compiling a new pattern or after
+     setting the match registers, so that the regex functions will be
+     able to free or re-allocate it properly.  */
+  struct re_registers m_search_regs;
+#define search_regs (current_thread->m_search_regs)
+
+  /* If non-zero the match data have been saved in saved_search_regs
+     during the execution of a sentinel or filter. */
+  int m_search_regs_saved;
+#define search_regs_saved (current_thread->m_search_regs_saved)
+
+  struct re_registers m_saved_search_regs;
+#define saved_search_regs (current_thread->m_saved_search_regs)
+
+  /* This is the string or buffer in which we
+     are matching.  It is used for looking up syntax properties.  */
+  Lisp_Object m_re_match_object;
+#define re_match_object (current_thread->m_re_match_object)
+
+  /* Set by `re_set_syntax' to the current regexp syntax to recognize.  Can
+     also be assigned to arbitrarily: each pattern buffer stores its own
+     syntax, so it can be changed between regex compilations.  */
+  reg_syntax_t m_re_syntax_options;
+#define re_syntax_options (current_thread->m_re_syntax_options)
+
+  /* Regexp to use to replace spaces, or NULL meaning don't.  */
+  /*re_char*/ unsigned char *m_whitespace_regexp;
+#define whitespace_regexp (current_thread->m_whitespace_regexp)
+};
+
+extern struct thread_state *current_thread;
+
+#endif /* THREAD_H */
diff --git a/src/window.c b/src/window.c
index f5622b217d7..e404b332516 100644
--- a/src/window.c
+++ b/src/window.c
@@ -5296,7 +5296,7 @@ struct save_window_data
     struct vectorlike_header header;
     Lisp_Object selected_frame;
     Lisp_Object current_window;
-    Lisp_Object current_buffer;
+    Lisp_Object f_current_buffer;
     Lisp_Object minibuf_scroll_window;
     Lisp_Object minibuf_selected_window;
     Lisp_Object root_window;
@@ -5377,7 +5377,7 @@ the return value is nil.  Otherwise the value is t.  */)
   data = (struct save_window_data *) XVECTOR (configuration);
   saved_windows = XVECTOR (data->saved_windows);
 
-  new_current_buffer = data->current_buffer;
+  new_current_buffer = data->f_current_buffer;
   if (NILP (BVAR (XBUFFER (new_current_buffer), name)))
     new_current_buffer = Qnil;
   else
@@ -6012,7 +6012,7 @@ saved by this function.  */)
   data->frame_tool_bar_lines = FRAME_TOOL_BAR_LINES (f);
   data->selected_frame = selected_frame;
   data->current_window = FRAME_SELECTED_WINDOW (f);
-  XSETBUFFER (data->current_buffer, current_buffer);
+  XSETBUFFER (data->f_current_buffer, current_buffer);
   data->minibuf_scroll_window = minibuf_level > 0 ? Vminibuf_scroll_window : Qnil;
   data->minibuf_selected_window = minibuf_level > 0 ? minibuf_selected_window : Qnil;
   data->root_window = FRAME_ROOT_WINDOW (f);
@@ -6416,7 +6416,7 @@ compare_window_configurations (Lisp_Object configuration1, Lisp_Object configura
       || d1->frame_lines != d2->frame_lines
       || d1->frame_menu_bar_lines != d2->frame_menu_bar_lines
       || !EQ (d1->selected_frame, d2->selected_frame)
-      || !EQ (d1->current_buffer, d2->current_buffer)
+      || !EQ (d1->f_current_buffer, d2->f_current_buffer)
       || (!ignore_positions
           && (!EQ (d1->minibuf_scroll_window, d2->minibuf_scroll_window)
               || !EQ (d1->minibuf_selected_window, d2->minibuf_selected_window)))