Commit e3b83880 authored by Stefan Monnier's avatar Stefan Monnier
Browse files

* src/alloc.c: Keep track of symbols referenced from pure space (bug#17168).

(symbol_block_pinned): New var.
(Fmake_symbol): Initialize `pinned'.
(purecopy): New function, extracted from Fpurecopy.  Mark symbols as
pinned and signal an error for un-purifiable objects.
(pure_cons): Use it.
(Fpurecopy): Use it, except for objects that can't be purified.
(mark_pinned_symbols): New function.
(Fgarbage_collect): Use it.
(gc_sweep): Remove hack made unnecessary.
* src/lisp.h (struct Lisp_Symbol): New bitfield `pinned'.
parent 190f899a
2014-04-07 Stefan Monnier <monnier@iro.umontreal.ca>
* lisp.h (struct Lisp_Symbol): New bitfield `pinned'.
* alloc.c: Keep track of symbols referenced from pure space (bug#17168).
(symbol_block_pinned): New var.
(Fmake_symbol): Initialize `pinned'.
(purecopy): New function, extracted from Fpurecopy. Mark symbols as
pinned and signal an error for un-purifiable objects.
(pure_cons): Use it.
(Fpurecopy): Use it, except for objects that can't be purified.
(mark_pinned_symbols): New function.
(Fgarbage_collect): Use it.
(gc_sweep): Remove hack made unnecessary.
2014-04-05 Glenn Morris <rgm@gnu.org>
* keyboard.c (Fopen_dribble_file): Doc tweak.
......
......@@ -3316,6 +3316,13 @@ struct symbol_block
static struct symbol_block *symbol_block;
static int symbol_block_index = SYMBOL_BLOCK_SIZE;
/* Pointer to the first symbol_block that contains pinned symbols.
Tests for 24.4 showed that at dump-time, Emacs contains about 15K symbols,
10K of which are pinned (and all but 250 of them are interned in obarray),
whereas a "typical session" has in the order of 30K symbols.
`symbol_block_pinned' lets mark_pinned_symbols scan only 15K symbols rather
than 30K to find the 10K symbols we need to mark. */
static struct symbol_block *symbol_block_pinned;
/* List of free symbols. */
......@@ -3368,10 +3375,11 @@ Its value is void, and its function definition and property list are nil. */)
SET_SYMBOL_VAL (p, Qunbound);
set_symbol_function (val, Qnil);
set_symbol_next (val, NULL);
p->gcmarkbit = 0;
p->gcmarkbit = false;
p->interned = SYMBOL_UNINTERNED;
p->constant = 0;
p->declared_special = 0;
p->declared_special = false;
p->pinned = false;
consing_since_gc += sizeof (struct Lisp_Symbol);
symbols_consed++;
total_free_symbols--;
......@@ -5173,6 +5181,8 @@ make_pure_c_string (const char *data, ptrdiff_t nchars)
return string;
}
static Lisp_Object purecopy (Lisp_Object obj);
/* Return a cons allocated from pure space. Give it pure copies
of CAR as car and CDR as cdr. */
......@@ -5182,8 +5192,8 @@ pure_cons (Lisp_Object car, Lisp_Object cdr)
Lisp_Object new;
struct Lisp_Cons *p = pure_alloc (sizeof *p, Lisp_Cons);
XSETCONS (new, p);
XSETCAR (new, Fpurecopy (car));
XSETCDR (new, Fpurecopy (cdr));
XSETCAR (new, purecopy (car));
XSETCDR (new, purecopy (cdr));
return new;
}
......@@ -5224,9 +5234,19 @@ Does not copy symbols. Copies strings without text properties. */)
{
if (NILP (Vpurify_flag))
return obj;
if (PURE_POINTER_P (XPNTR (obj)))
else if (MARKERP (obj) || OVERLAYP (obj)
|| HASH_TABLE_P (obj) || SYMBOLP (obj))
/* Can't purify those. */
return obj;
else
return purecopy (obj);
}
static Lisp_Object
purecopy (Lisp_Object obj)
{
if (PURE_POINTER_P (XPNTR (obj)) || INTEGERP (obj) || SUBRP (obj))
return obj; /* Already pure. */
if (HASH_TABLE_P (Vpurify_flag)) /* Hash consing. */
{
......@@ -5254,7 +5274,7 @@ Does not copy symbols. Copies strings without text properties. */)
size &= PSEUDOVECTOR_SIZE_MASK;
vec = XVECTOR (make_pure_vector (size));
for (i = 0; i < size; i++)
vec->contents[i] = Fpurecopy (AREF (obj, i));
vec->contents[i] = purecopy (AREF (obj, i));
if (COMPILEDP (obj))
{
XSETPVECTYPE (vec, PVEC_COMPILED);
......@@ -5263,11 +5283,23 @@ Does not copy symbols. Copies strings without text properties. */)
else
XSETVECTOR (obj, vec);
}
else if (MARKERP (obj))
error ("Attempt to copy a marker to pure storage");
else if (SYMBOLP (obj))
{
if (!XSYMBOL (obj)->pinned)
{ /* 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;
symbol_block_pinned = symbol_block;
}
return obj;
}
else
/* Not purified, don't hash-cons. */
return obj;
{
Lisp_Object args[2];
args[0] = build_pure_c_string ("Don't know how to purify: %S");
args[1] = obj;
Fsignal (Qerror, (Fcons (Fformat (2, args), Qnil)));
}
if (HASH_TABLE_P (Vpurify_flag)) /* Hash consing. */
Fputhash (obj, obj, Vpurify_flag);
......@@ -5430,6 +5462,24 @@ compact_undo_list (Lisp_Object list)
return list;
}
static void
mark_pinned_symbols (void)
{
struct symbol_block *sblk;
int lim = (symbol_block_pinned == symbol_block
? symbol_block_index : SYMBOL_BLOCK_SIZE);
for (sblk = symbol_block_pinned; sblk; sblk = sblk->next)
{
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));
lim = SYMBOL_BLOCK_SIZE;
}
}
DEFUN ("garbage-collect", Fgarbage_collect, Sgarbage_collect, 0, 0, "",
doc: /* Reclaim storage for Lisp objects no longer needed.
Garbage collection happens automatically if you cons more than
......@@ -5532,6 +5582,7 @@ See Info node `(elisp)Garbage Collection'. */)
for (i = 0; i < staticidx; i++)
mark_object (*staticvec[i]);
mark_pinned_symbols ();
mark_specpdl ();
mark_terminals ();
mark_kboards ();
......@@ -6536,12 +6587,7 @@ gc_sweep (void)
for (; sym < end; ++sym)
{
/* Check if the symbol was created during loadup. In such a case
it might be pointed to by pure bytecode which we don't trace,
so we conservatively assume that it is live. */
bool pure_p = PURE_POINTER_P (XSTRING (sym->s.name));
if (!sym->s.gcmarkbit && !pure_p)
if (!sym->s.gcmarkbit)
{
if (sym->s.redirect == SYMBOL_LOCALIZED)
xfree (SYMBOL_BLV (&sym->s));
......@@ -6555,8 +6601,7 @@ gc_sweep (void)
else
{
++num_used;
if (!pure_p)
eassert (!STRING_MARKED_P (XSTRING (sym->s.name)));
eassert (!STRING_MARKED_P (XSTRING (sym->s.name)));
sym->s.gcmarkbit = 0;
}
}
......
......@@ -1568,6 +1568,9 @@ struct Lisp_Symbol
special (with `defvar' etc), and shouldn't be lexically bound. */
bool_bf declared_special : 1;
/* True if pointed to from purespace and hence can't be GC'd. */
bool_bf pinned : 1;
/* The symbol's name, as a Lisp string. */
Lisp_Object name;
......
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