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Minor pseudovector allocation cleanups

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* src/alloc.c (VECTOR_BLOCK_SIZE, VECTOR_BLOCK_BYTES)
(VBLOCK_BYTES_MIN, VBLOCK_BYTES_MAX, VECTOR_MAX_FREE_LIST_INDEX):
Prefer enums to macros where either will do.
(allocate_vector_from_block): Arg is ptrdiff_t, not size_t.
Use eassume instead of eassert.
(PSEUDOVEC_STRUCT): New macro, which verifies the already-existing
assumption that the vector-like objects are small.
(cleanup_vector): Use it.  Use if-then-else systematically;
this lets GCC do a bit better job.

2018-08-08  Paul Eggert  <eggert@cs.ucla.edu>

* src/alloc.c (VBLOCK_BYTES_MAX): Use vroundup_ct, not
vroundup, so that can be used in static assertions.
This commit is contained in:
Paul Eggert 2018-08-08 18:51:35 -07:00
parent 7eef590870
commit 63a8f4cfd7
1 changed files with 36 additions and 27 deletions
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63
src/alloc.c
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@ -2932,7 +2932,7 @@ set_next_vector (struct Lisp_Vector *v, struct Lisp_Vector *p)
for the most common cases; it's not required to be a power of two, but
it's expected to be a mult-of-ROUNDUP_SIZE (see below). */
#define VECTOR_BLOCK_SIZE 4096
enum { VECTOR_BLOCK_SIZE = 4096 };
/* Vector size requests are a multiple of this. */
enum { roundup_size = COMMON_MULTIPLE (LISP_ALIGNMENT, word_size) };
@ -2948,22 +2948,21 @@ verify (VECTOR_BLOCK_SIZE <= (1 << PSEUDOVECTOR_SIZE_BITS));
/* Rounding helps to maintain alignment constraints if USE_LSB_TAG. */
#define VECTOR_BLOCK_BYTES (VECTOR_BLOCK_SIZE - vroundup_ct (sizeof (void *)))
enum {VECTOR_BLOCK_BYTES = VECTOR_BLOCK_SIZE - vroundup_ct (sizeof (void *))};
/* Size of the minimal vector allocated from block. */
#define VBLOCK_BYTES_MIN vroundup_ct (header_size + sizeof (Lisp_Object))
enum { VBLOCK_BYTES_MIN = vroundup_ct (header_size + sizeof (Lisp_Object)) };
/* Size of the largest vector allocated from block. */
#define VBLOCK_BYTES_MAX \
vroundup ((VECTOR_BLOCK_BYTES / 2) - word_size)
enum { VBLOCK_BYTES_MAX = vroundup_ct ((VECTOR_BLOCK_BYTES / 2) - word_size) };
/* We maintain one free list for each possible block-allocated
vector size, and this is the number of free lists we have. */
#define VECTOR_MAX_FREE_LIST_INDEX \
((VECTOR_BLOCK_BYTES - VBLOCK_BYTES_MIN) / roundup_size + 1)
enum { VECTOR_MAX_FREE_LIST_INDEX =
(VECTOR_BLOCK_BYTES - VBLOCK_BYTES_MIN) / roundup_size + 1 };
/* Common shortcut to advance vector pointer over a block data. */
@ -3090,14 +3089,14 @@ init_vectors (void)
/* Allocate vector from a vector block. */
static struct Lisp_Vector *
allocate_vector_from_block (size_t nbytes)
allocate_vector_from_block (ptrdiff_t nbytes)
{
struct Lisp_Vector *vector;
struct vector_block *block;
size_t index, restbytes;
eassert (VBLOCK_BYTES_MIN <= nbytes && nbytes <= VBLOCK_BYTES_MAX);
eassert (nbytes % roundup_size == 0);
eassume (VBLOCK_BYTES_MIN <= nbytes && nbytes <= VBLOCK_BYTES_MAX);
eassume (nbytes % roundup_size == 0);
/* First, try to allocate from a free list
containing vectors of the requested size. */
@ -3182,35 +3181,45 @@ vector_nbytes (struct Lisp_Vector *v)
return vroundup (header_size + word_size * nwords);
}
/* Convert a pseudovector pointer P to its underlying struct T pointer.
Verify that the struct is small, since cleanup_vector is called
only on small vector-like objects. */
#define PSEUDOVEC_STRUCT(p, t) \
verify_expr ((header_size + VECSIZE (struct t) * word_size \
<= VBLOCK_BYTES_MAX), \
(struct t *) (p))
/* Release extra resources still in use by VECTOR, which may be any
vector-like object. */
small vector-like object. */
static void
cleanup_vector (struct Lisp_Vector *vector)
{
detect_suspicious_free (vector);
if (PSEUDOVECTOR_TYPEP (&vector->header, PVEC_FONT)
&& ((vector->header.size & PSEUDOVECTOR_SIZE_MASK)
== FONT_OBJECT_MAX))
if (PSEUDOVECTOR_TYPEP (&vector->header, PVEC_FONT))
{
struct font_driver const *drv = ((struct font *) vector)->driver;
/* The font driver might sometimes be NULL, e.g. if Emacs was
interrupted before it had time to set it up. */
if (drv)
if ((vector->header.size & PSEUDOVECTOR_SIZE_MASK) == FONT_OBJECT_MAX)
{
/* Attempt to catch subtle bugs like Bug#16140. */
eassert (valid_font_driver (drv));
drv->close ((struct font *) vector);
struct font *font = PSEUDOVEC_STRUCT (vector, font);
struct font_driver const *drv = font->driver;
/* The font driver might sometimes be NULL, e.g. if Emacs was
interrupted before it had time to set it up. */
if (drv)
{
/* Attempt to catch subtle bugs like Bug#16140. */
eassert (valid_font_driver (drv));
drv->close (font);
}
}
}
if (PSEUDOVECTOR_TYPEP (&vector->header, PVEC_THREAD))
finalize_one_thread ((struct thread_state *) vector);
else if (PSEUDOVECTOR_TYPEP (&vector->header, PVEC_THREAD))
finalize_one_thread (PSEUDOVEC_STRUCT (vector, thread_state));
else if (PSEUDOVECTOR_TYPEP (&vector->header, PVEC_MUTEX))
finalize_one_mutex ((struct Lisp_Mutex *) vector);
finalize_one_mutex (PSEUDOVEC_STRUCT (vector, Lisp_Mutex));
else if (PSEUDOVECTOR_TYPEP (&vector->header, PVEC_CONDVAR))
finalize_one_condvar ((struct Lisp_CondVar *) vector);
finalize_one_condvar (PSEUDOVEC_STRUCT (vector, Lisp_CondVar));
}
/* Reclaim space used by unmarked vectors. */