* lib/obstack.c (MAX, DEFAULT_ALIGNMENT, DEFAULT_ROUNDING): Remove.
(_obstack_begin_worker): Use __alignof__ (max_align_t)
instead of calculating it by hand, possibly incorrectly
on oddball platforms. Estimate a good size of 4000 bytes
rather than using a no-longer-valid value.
* modules/obstack (Depends-on): Add stddef-h, for max_align_t.
---
ChangeLog | 8 ++++++++
lib/obstack.c | 36 +++---------------------------------
modules/obstack | 1 +
3 files changed, 12 insertions(+), 33 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index eb0ba5d166..20f9e7bc3c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,13 @@
2025-05-05 Paul Eggert <egg...@cs.ucla.edu>
+ obstack: simplify default size, alignment
+ * lib/obstack.c (MAX, DEFAULT_ALIGNMENT, DEFAULT_ROUNDING): Remove.
+ (_obstack_begin_worker): Use __alignof__ (max_align_t)
+ instead of calculating it by hand, possibly incorrectly
+ on oddball platforms. Estimate a good size of 4000 bytes
+ rather than using a no-longer-valid value.
+ * modules/obstack (Depends-on): Add stddef-h, for max_align_t.
+
obstack: use signed chunk sizes
* lib/obstack.in.h (_OBSTACK_CHUNK_SIZE_T) [!__GL_GNULIB_HEADER]:
Now long, not unsigned long, since that’s what glibc does.
diff --git a/lib/obstack.c b/lib/obstack.c
index b319c8f7d3..1fac1cd404 100644
--- a/lib/obstack.c
+++ b/lib/obstack.c
@@ -57,24 +57,6 @@ align_size_up (size_t mask, size_t size)
return size + (mask & -size);
}
-#ifndef MAX
-# define MAX(a,b) ((a) > (b) ? (a) : (b))
-#endif
-
-/* Determine default alignment. */
-
-/* If malloc were really smart, it would round addresses to DEFAULT_ALIGNMENT.
- But in fact it might be less smart and round addresses to as much as
- DEFAULT_ROUNDING. So we prepare for it to do that.
-
- DEFAULT_ALIGNMENT cannot be an enum constant; see gnulib's alignof.h. */
-#define DEFAULT_ALIGNMENT MAX (__alignof__ (long double), \
- MAX (__alignof__ (uintmax_t), \
- __alignof__ (void *)))
-#define DEFAULT_ROUNDING MAX (sizeof (long double), \
- MAX (sizeof (uintmax_t),
\
- sizeof (void *)))
-
/* Call functions with either the traditional malloc/free calling
interface, or the mmalloc/mfree interface (that adds an extra first
argument), based on the value of use_extra_arg. */
@@ -111,7 +93,7 @@ _obstack_begin_worker (struct obstack *h,
struct _obstack_chunk *chunk; /* points to new chunk */
if (alignment == 0)
- alignment = DEFAULT_ALIGNMENT;
+ alignment = __alignof__ (max_align_t);
/* The minimum size to request from the allocator, such that the
result is guaranteed to have enough room to start with the struct
@@ -131,20 +113,8 @@ _obstack_begin_worker (struct obstack *h,
size = aligned_prefix_size;
/* For speed in the typical case, allocate at least a "good" size. */
-
- /* 12 is sizeof (mhead) and 4 is EXTRA from GNU malloc.
- Use the values for range checking, because if range checking is off,
- the extra bytes won't be missed terribly, but if range checking is on
- and we used a larger request, a whole extra 4096 bytes would be
- allocated.
-
- These number are irrelevant to the new GNU malloc. I suspect it is
- less sensitive to the size of the request. */
- int extra = ((((12 + DEFAULT_ROUNDING - 1) & ~(DEFAULT_ROUNDING - 1))
- + 4 + DEFAULT_ROUNDING - 1)
- & ~(DEFAULT_ROUNDING - 1));
- int good_size = 4096 - extra;
- if (0 <= good_size && size < good_size)
+ int good_size = 4000;
+ if (size < good_size)
size = good_size;
}
diff --git a/modules/obstack b/modules/obstack
index 4f62f64bba..f22a7a1cc4 100644
--- a/modules/obstack
+++ b/modules/obstack
@@ -13,6 +13,7 @@ flexmember [test $HAVE_OBSTACK = 0 || test
$REPLACE_OBSTACK = 1]
gettext-h [test $HAVE_OBSTACK = 0 || test $REPLACE_OBSTACK = 1]
gnulib-i18n [test $HAVE_OBSTACK = 0 || test $REPLACE_OBSTACK = 1]
exitfail [test $HAVE_OBSTACK = 0 || test $REPLACE_OBSTACK = 1]
+stddef-h [test $HAVE_OBSTACK = 0 || test $REPLACE_OBSTACK = 1]
stdint-h [test $HAVE_OBSTACK = 0 || test $REPLACE_OBSTACK = 1]
stdlib-h [test $HAVE_OBSTACK = 0 || test $REPLACE_OBSTACK = 1]
--
2.49.0
