Compute C decls for DEFSYMs automatically

Fixes Bug#15880.
This patch also makes Q constants (e.g., Qnil) constant addresses
from the C point of view.
* make-docfile.c: Revamp to generate table of symbols, too.
Include <stdbool.h>.
(xstrdup): New function.
(main): Don't process the same file twice.
(SYMBOL): New constant in enum global_type.
(struct symbol): Turn 'value' member into a union, either v.value
for int or v.svalue for string.  All uses changed.
(add_global): New arg svalue, which overrides value, so that globals
can have a string value.
(close_emacs_global): New arg num_symbols; all uses changed.
Output lispsym decl.
(write_globals): Output symbol globals too.  Output more
ATTRIBUTE_CONST, now that Qnil etc. are C constants.
Output defsym_name table.
(scan_c_file): Move most of guts into ...
(scan_c_stream): ... new function.  Scan for DEFSYMs and
record symbols found.  Don't read past EOF if file doesn't
end in newline.
* alloc.c, bidi.c, buffer.c, bytecode.c, callint.c, casefiddle:
* casetab.c, category.c, ccl.c, charset.c, chartab.c, cmds.c, coding.c:
* composite.c, data.c, dbusbind.c, decompress.c, dired.c, dispnew.c:
* doc.c, editfns.c, emacs.c, eval.c, fileio.c, fns.c, font.c, fontset.c:
* frame.c, fringe.c, ftfont.c, ftxfont.c, gfilenotify.c, gnutls.c:
* image.c, inotify.c, insdel.c, keyboard.c, keymap.c, lread.c:
* macfont.m, macros.c, minibuf.c, nsfns.m, nsfont.m, nsimage.m:
* nsmenu.m, nsselect.m, nsterm.m, print.c, process.c, profiler.c:
* search.c, sound.c, syntax.c, term.c, terminal.c, textprop.c, undo.c:
* window.c, xdisp.c, xfaces.c, xfns.c, xftfont.c, xmenu.c, xml.c:
* xselect.c, xsettings.c, xterm.c:
Remove Q vars that represent symbols (e.g., Qnil, Qt, Qemacs).
These names are now defined automatically by make-docfile.
* alloc.c (init_symbol): New function.
(Fmake_symbol): Use it.
(c_symbol_p): New function.
(valid_lisp_object_p, purecopy): Use it.
* alloc.c (marked_pinned_symbols):
Use make_lisp_symbol instead of make_lisp_ptr.
(garbage_collect_1): Mark lispsym symbols.
(CHECK_ALLOCATED_AND_LIVE_SYMBOL): New macro.
(mark_object): Use it.
(sweep_symbols): Sweep lispsym symbols.
(symbol_uses_obj): New function.
(which_symbols): Use it.  Work for lispsym symbols, too.
(init_alloc_once): Initialize Vpurify_flag here; no need to wait,
since Qt's address is already known now.
(syms_of_alloc): Add lispsym count to symbols_consed.
* buffer.c (init_buffer_once): Compare to Qnil, not to make_number (0),
when testing whether storage is all bits zero.
* dispextern (struct image_type):
* font.c (font_property_table):
* frame.c (struct frame_parm_table, frame_parms):
* keyboard.c (scroll_bar_parts, struct event_head):
* xdisp.c (struct props):
Use XSYMBOL_INIT (Qfoo) and struct Lisp_Symbol * rather than &Qfoo and
Lisp_Object *, since Qfoo is no longer an object whose address can be
taken.  All uses changed.
* eval.c (run_hook): New function.  Most uses of Frun_hooks changed to
use it, so that they no longer need to take the address of a Lisp sym.
(syms_of_eval): Don't use DEFSYM on Vrun_hooks, as it's a variable.
* frame.c (syms_of_frame): Add defsyms for the frame_parms table.
* keyboard.c (syms_of_keyboard): Don't DEFSYM Qmenu_bar here.
DEFSYM Qdeactivate_mark before the corresponding var.
* keymap.c (syms_of_keymap): Use DEFSYM for Qmenu_bar and Qmode_line
instead of interning their symbols; this avoids duplicates.
(LISP_INITIALLY, TAG_PTR)
(DEFINE_LISP_SYMBOL_BEGIN, DEFINE_LISP_SYMBOL_END, XSYMBOL_INIT):
New macros.
(LISP_INITIALLY_ZERO): Use it.
(enum symbol_interned, enum symbol_redirect, struct Lisp_Symbol)
(EXFUN, DEFUN_ARGS_MANY, DEFUN_ARGS_UNEVALLED, DEFUN_ARGS_*):
Move decls up, to avoid forward uses.  Include globals.h earlier, too.
(make_lisp_symbol): New function.
(XSETSYMBOL): Use it.
(DEFSYM): Now just a placeholder for make-docfile.
* lread.c (DEFINE_SYMBOLS): Define, for globals.h.
(intern_sym): New function, with body taken from old intern_driver.
(intern_driver): Use it.  Last arg is now Lisp integer, not ptrdiff_t.
All uses changed.
(define_symbol): New function.
(init_obarray): Define the C symbols taken from lispsym.
Use plain DEFSYM for Qt and Qnil.
* syntax.c (init_syntax_once): No need to worry about
Qchar_table_extra_slots.

1 files changed, 90 insertions, 57 deletions

diff --git a/src/alloc.c b/src/alloc.c
index ecea3e8ac7d..712c8f771f7 100644
--- a/src/alloc.c
+++ b/src/alloc.c
@@ -263,23 +263,6 @@ no_sanitize_memcpy (void *dest, void const *src, size_t size)
 
 #endif /* MAX_SAVE_STACK > 0 */
 
-static Lisp_Object Qconses;
-static Lisp_Object Qsymbols;
-static Lisp_Object Qmiscs;
-static Lisp_Object Qstrings;
-static Lisp_Object Qvectors;
-static Lisp_Object Qfloats;
-static Lisp_Object Qintervals;
-static Lisp_Object Qbuffers;
-static Lisp_Object Qstring_bytes, Qvector_slots, Qheap;
-static Lisp_Object Qgc_cons_threshold;
-Lisp_Object Qautomatic_gc;
-Lisp_Object Qchar_table_extra_slots;
-
-/* Hook run after GC has finished.  */
-
-static Lisp_Object Qpost_gc_hook;
-
 static void mark_terminals (void);
 static void gc_sweep (void);
 static Lisp_Object make_pure_vector (ptrdiff_t);
@@ -3410,13 +3393,29 @@ set_symbol_name (Lisp_Object sym, Lisp_Object name)
   XSYMBOL (sym)->name = name;
 }
 
+void
+init_symbol (Lisp_Object val, Lisp_Object name)
+{
+  struct Lisp_Symbol *p = XSYMBOL (val);
+  set_symbol_name (val, name);
+  set_symbol_plist (val, Qnil);
+  p->redirect = SYMBOL_PLAINVAL;
+  SET_SYMBOL_VAL (p, Qunbound);
+  set_symbol_function (val, Qnil);
+  set_symbol_next (val, NULL);
+  p->gcmarkbit = false;
+  p->interned = SYMBOL_UNINTERNED;
+  p->constant = 0;
+  p->declared_special = false;
+  p->pinned = false;
+}
+
 DEFUN ("make-symbol", Fmake_symbol, Smake_symbol, 1, 1, 0,
        doc: /* Return a newly allocated uninterned symbol whose name is NAME.
 Its value is void, and its function definition and property list are nil.  */)
   (Lisp_Object name)
 {
-  register Lisp_Object val;
-  register struct Lisp_Symbol *p;
+  Lisp_Object val;
 
   CHECK_STRING (name);
 
@@ -3444,18 +3443,7 @@ Its value is void, and its function definition and property list are nil.  */)
 
   MALLOC_UNBLOCK_INPUT;
 
-  p = XSYMBOL (val);
-  set_symbol_name (val, name);
-  set_symbol_plist (val, Qnil);
-  p->redirect = SYMBOL_PLAINVAL;
-  SET_SYMBOL_VAL (p, Qunbound);
-  set_symbol_function (val, Qnil);
-  set_symbol_next (val, NULL);
-  p->gcmarkbit = false;
-  p->interned = SYMBOL_UNINTERNED;
-  p->constant = 0;
-  p->declared_special = false;
-  p->pinned = false;
+  init_symbol (val, name);
   consing_since_gc += sizeof (struct Lisp_Symbol);
   symbols_consed++;
   total_free_symbols--;
@@ -4925,6 +4913,14 @@ mark_stack (void *end)
 
 #endif /* GC_MARK_STACK != 0 */
 
+static bool
+c_symbol_p (struct Lisp_Symbol *sym)
+{
+  char *lispsym_ptr = (char *) lispsym;
+  char *sym_ptr = (char *) sym;
+  ptrdiff_t lispsym_offset = sym_ptr - lispsym_ptr;
+  return 0 <= lispsym_offset && lispsym_offset < sizeof lispsym;
+}
 
 /* Determine whether it is safe to access memory at address P.  */
 static int
@@ -4978,6 +4974,9 @@ valid_lisp_object_p (Lisp_Object obj)
   if (PURE_POINTER_P (p))
     return 1;
 
+  if (SYMBOLP (obj) && c_symbol_p (p))
+    return ((char *) p - (char *) lispsym) % sizeof lispsym[0] == 0;
+
   if (p == &buffer_defaults || p == &buffer_local_symbols)
     return 2;
 
@@ -5343,7 +5342,7 @@ purecopy (Lisp_Object obj)
     }
   else if (SYMBOLP (obj))
     {
-      if (!XSYMBOL (obj)->pinned)
+      if (!XSYMBOL (obj)->pinned && !c_symbol_p (XSYMBOL (obj)))
         { /* We can't purify them, but they appear in many pure objects.
              Mark them as `pinned' so we know to mark them at every GC cycle.  */
           XSYMBOL (obj)->pinned = true;
@@ -5532,7 +5531,7 @@ mark_pinned_symbols (void)
       union aligned_Lisp_Symbol *sym = sblk->symbols, *end = sym + lim;
       for (; sym < end; ++sym)
         if (sym->s.pinned)
-          mark_object (make_lisp_ptr (&sym->s, Lisp_Symbol));
+          mark_object (make_lisp_symbol (&sym->s));
 
       lim = SYMBOL_BLOCK_SIZE;
     }
@@ -5566,7 +5565,7 @@ garbage_collect_1 (void *end)
     return Qnil;
 
   /* Record this function, so it appears on the profiler's backtraces.  */
-  record_in_backtrace (Qautomatic_gc, &Qnil, 0);
+  record_in_backtrace (Qautomatic_gc, 0, 0);
 
   check_cons_list ();
 
@@ -5630,6 +5629,9 @@ garbage_collect_1 (void *end)
   mark_buffer (&buffer_defaults);
   mark_buffer (&buffer_local_symbols);
 
+  for (i = 0; i < ARRAYELTS (lispsym); i++)
+    mark_object (make_lisp_symbol (&lispsym[i]));
+
   for (i = 0; i < staticidx; i++)
     mark_object (*staticvec[i]);
 
@@ -6193,17 +6195,28 @@ mark_object (Lisp_Object arg)
       emacs_abort ();                           \
   } while (0)
 
-  /* Check both of the above conditions.  */
+  /* Check both of the above conditions, for non-symbols.  */
 #define CHECK_ALLOCATED_AND_LIVE(LIVEP)         \
   do {                                          \
     CHECK_ALLOCATED ();                         \
     CHECK_LIVE (LIVEP);                         \
   } while (0)                                   \
 
+  /* Check both of the above conditions, for symbols.  */
+#define CHECK_ALLOCATED_AND_LIVE_SYMBOL()       \
+  do {                                          \
+    if (!c_symbol_p (ptr))                      \
+      {                                         \
+        CHECK_ALLOCATED ();                     \
+        CHECK_LIVE (live_symbol_p);             \
+      }                                         \
+  } while (0)                                   \
+
 #else /* not GC_CHECK_MARKED_OBJECTS */
 
-#define CHECK_LIVE(LIVEP)               ((void) 0)
-#define CHECK_ALLOCATED_AND_LIVE(LIVEP) ((void) 0)
+#define CHECK_LIVE(LIVEP)                       ((void) 0)
+#define CHECK_ALLOCATED_AND_LIVE(LIVEP)         ((void) 0)
+#define CHECK_ALLOCATED_AND_LIVE_SYMBOL()       ((void) 0)
 
 #endif /* not GC_CHECK_MARKED_OBJECTS */
 
@@ -6363,7 +6376,7 @@ mark_object (Lisp_Object arg)
       nextsym:
         if (ptr->gcmarkbit)
           break;
-        CHECK_ALLOCATED_AND_LIVE (live_symbol_p);
+        CHECK_ALLOCATED_AND_LIVE_SYMBOL ();
         ptr->gcmarkbit = 1;
         /* Attempt to catch bogus objects.  */
         eassert (valid_lisp_object_p (ptr->function));
@@ -6720,13 +6733,16 @@ NO_INLINE /* For better stack traces */
 static void
 sweep_symbols (void)
 {
-  register struct symbol_block *sblk;
+  struct symbol_block *sblk;
   struct symbol_block **sprev = &symbol_block;
-  register int lim = symbol_block_index;
-  EMACS_INT num_free = 0, num_used = 0;
+  int lim = symbol_block_index;
+  EMACS_INT num_free = 0, num_used = ARRAYELTS (lispsym);
 
   symbol_free_list = NULL;
 
+  for (int i = 0; i < ARRAYELTS (lispsym); i++)
+    lispsym[i].gcmarkbit = 0;
+
   for (sblk = symbol_block; sblk; sblk = *sprev)
     {
       int this_free = 0;
@@ -6974,6 +6990,21 @@ Frames, windows, buffers, and subprocesses count as vectors
                 bounded_number (strings_consed));
 }
 
+static bool
+symbol_uses_obj (Lisp_Object symbol, Lisp_Object obj)
+{
+  struct Lisp_Symbol *sym = XSYMBOL (symbol);
+  Lisp_Object val = find_symbol_value (symbol);
+  return (EQ (val, obj)
+          || EQ (sym->function, obj)
+          || (!NILP (sym->function)
+              && COMPILEDP (sym->function)
+              && EQ (AREF (sym->function, COMPILED_BYTECODE), obj))
+          || (!NILP (val)
+              && COMPILEDP (val)
+              && EQ (AREF (val, COMPILED_BYTECODE), obj)));
+}
+
 /* Find at most FIND_MAX symbols which have OBJ as their value or
    function.  This is used in gdbinit's `xwhichsymbols' command.  */
 
@@ -6986,6 +7017,17 @@ which_symbols (Lisp_Object obj, EMACS_INT find_max)
 
    if (! DEADP (obj))
      {
+       for (int i = 0; i < ARRAYELTS (lispsym); i++)
+         {
+           Lisp_Object sym = make_lisp_symbol (&lispsym[i]);
+           if (symbol_uses_obj (sym, obj))
+             {
+               found = Fcons (sym, found);
+               if (--find_max == 0)
+                 goto out;
+             }
+         }
+
        for (sblk = symbol_block; sblk; sblk = sblk->next)
          {
            union aligned_Lisp_Symbol *aligned_sym = sblk->symbols;
@@ -6993,25 +7035,13 @@ which_symbols (Lisp_Object obj, EMACS_INT find_max)
 
            for (bn = 0; bn < SYMBOL_BLOCK_SIZE; bn++, aligned_sym++)
              {
-               struct Lisp_Symbol *sym = &aligned_sym->s;
-               Lisp_Object val;
-               Lisp_Object tem;
-
                if (sblk == symbol_block && bn >= symbol_block_index)
                  break;
 
-               XSETSYMBOL (tem, sym);
-               val = find_symbol_value (tem);
-               if (EQ (val, obj)
-                   || EQ (sym->function, obj)
-                   || (!NILP (sym->function)
-                       && COMPILEDP (sym->function)
-                       && EQ (AREF (sym->function, COMPILED_BYTECODE), obj))
-                   || (!NILP (val)
-                       && COMPILEDP (val)
-                       && EQ (AREF (val, COMPILED_BYTECODE), obj)))
+               Lisp_Object sym = make_lisp_symbol (&aligned_sym->s);
+               if (symbol_uses_obj (sym, obj))
                  {
-                   found = Fcons (tem, found);
+                   found = Fcons (sym, found);
                    if (--find_max == 0)
                      goto out;
                  }
@@ -7154,7 +7184,9 @@ verify_alloca (void)
 void
 init_alloc_once (void)
 {
-  /* Used to do Vpurify_flag = Qt here, but Qt isn't set up yet!  */
+  /* Even though Qt's contents are not set up, its address is known.  */
+  Vpurify_flag = Qt;
+
   purebeg = PUREBEG;
   pure_size = PURESIZE;
 
@@ -7230,6 +7262,7 @@ If this portion is smaller than `gc-cons-threshold', this is ignored.  */);
 
   DEFVAR_INT ("symbols-consed", symbols_consed,
               doc: /* Number of symbols that have been consed so far.  */);
+  symbols_consed += ARRAYELTS (lispsym);
 
   DEFVAR_INT ("string-chars-consed", string_chars_consed,
               doc: /* Number of string characters that have been consed so far.  */);