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master 09fecae877 3/3: Count bytes, not records, in specpdl_ref
From: |
Mattias Engdegård |
Subject: |
master 09fecae877 3/3: Count bytes, not records, in specpdl_ref |
Date: |
Sat, 12 Feb 2022 12:32:58 -0500 (EST) |
branch: master
commit 09fecae87747291afcc9f59c985e3d804de961c3
Author: Mattias Engdegård <mattiase@acm.org>
Commit: Mattias Engdegård <mattiase@acm.org>
Count bytes, not records, in specpdl_ref
SPECPDL_INDEX becomes much faster because the pointer subtraction,
expensive because of the inconveniently sized specpdl records, is now
gone. This translates to a useful speedup on a wide variety of code.
* src/lisp.h (specpdl_ref, wrap_specpdl_ref, unwrap_specpdl_ref):
Rename member.
(specpdl_count_to_ref, specpdl_ref_to_count)
(specpdl_ref_add, specpdl_ref_to_ptr, SPECPDL_INDEX):
Count offset in bytes rather than in records.
---
src/lisp.h | 24 +++++++++++++-----------
1 file changed, 13 insertions(+), 11 deletions(-)
diff --git a/src/lisp.h b/src/lisp.h
index 9b82307f67..f27c2ad2dd 100644
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -3356,23 +3356,24 @@ union specbinding
#define WRAP_SPECPDL_REF 1
#endif
-/* Abstract reference to to a specpdl entry. */
+/* Abstract reference to to a specpdl entry.
+ The number is always a multiple of sizeof (union specbinding). */
#ifdef WRAP_SPECPDL_REF
/* Use a proper type for specpdl_ref if it does not make the code slower,
since the type checking is quite useful. */
-typedef struct { ptrdiff_t n; } specpdl_ref;
+typedef struct { ptrdiff_t bytes; } specpdl_ref;
#else
typedef ptrdiff_t specpdl_ref;
#endif
/* Internal use only. */
INLINE specpdl_ref
-wrap_specpdl_ref (ptrdiff_t count)
+wrap_specpdl_ref (ptrdiff_t bytes)
{
#ifdef WRAP_SPECPDL_REF
- return (specpdl_ref) {.n = count};
+ return (specpdl_ref){.bytes = bytes};
#else
- return count;
+ return bytes;
#endif
}
@@ -3381,7 +3382,7 @@ INLINE ptrdiff_t
unwrap_specpdl_ref (specpdl_ref ref)
{
#ifdef WRAP_SPECPDL_REF
- return ref.n;
+ return ref.bytes;
#else
return ref;
#endif
@@ -3390,13 +3391,13 @@ unwrap_specpdl_ref (specpdl_ref ref)
INLINE specpdl_ref
specpdl_count_to_ref (ptrdiff_t count)
{
- return wrap_specpdl_ref (count);
+ return wrap_specpdl_ref (count * sizeof (union specbinding));
}
INLINE ptrdiff_t
specpdl_ref_to_count (specpdl_ref ref)
{
- return unwrap_specpdl_ref (ref);
+ return unwrap_specpdl_ref (ref) / sizeof (union specbinding);
}
/* Whether two `specpdl_ref' refer to the same entry. */
@@ -3430,20 +3431,21 @@ make_invalid_specpdl_ref (void)
INLINE specpdl_ref
specpdl_ref_add (specpdl_ref ref, ptrdiff_t delta)
{
- return specpdl_count_to_ref (specpdl_ref_to_count (ref) + delta);
+ return wrap_specpdl_ref (unwrap_specpdl_ref (ref)
+ + delta * sizeof (union specbinding));
}
INLINE union specbinding *
specpdl_ref_to_ptr (specpdl_ref ref)
{
- return specpdl + specpdl_ref_to_count (ref);
+ return (union specbinding *)((char *)specpdl + unwrap_specpdl_ref (ref));
}
/* Return a reference to the most recent specpdl entry. */
INLINE specpdl_ref
SPECPDL_INDEX (void)
{
- return specpdl_count_to_ref (specpdl_ptr - specpdl);
+ return wrap_specpdl_ref ((char *)specpdl_ptr - (char *)specpdl);
}
INLINE bool