News
New SBCL versions are usually released at the end of each
month: check the Sourceforge File List to see the current version. The new features of the two most recent SBCL releases are listed below.
Please see the complete news page for details on all historical SBCL releases.
New in version 2.5.7, 2025-07-26
Back to top- enhancement: the encapsulate mechanism can be used to wrap functions that
are currently not FBOUNDP.
- bug fix: internal compiler error in a failure of stack analysis during
propagation of dynamic-extent. (#2113935)
- bug fix: address regression in type inference for TRUNCATE and other
division-related operators. (#2115305, reported by Vasiliy Postnicov)
- bug fix: cleanup of the main thread is performed more carefully when SBCL
is used as a shared library. (#2115669, reported by Fedorov Alexander)
- bug fix: the compiler does not lose track of the types of specialized
external entry points for user-defined functions. (#2115955, reported
by Matt Kaufmann)
- bug fix: adjust compiler template argument acceptability for increased
usage scope. (#2116150)
- bug fix: provide a stub for ROTATE-RIGHT-WORD for constant-folding during
compilation. (#2117080)
- bug fix: provide a stub for %MAKE-DOUBLE-FLOAT for constant-folding during
compilation. (reported by Eric Marsden)
- bug fix: don't loop infinitely in the presence of type-mismatching
circular #S read syntax. (reported by Bohong Huang)
- optimization: calls to SLOT-VALUE (and related functions) within methods,
on values that are not a specialized argument to those methods, are
optimized similarly to calls to SLOT-VALUE in non-method code.
- optimization: calls to REPLACE with VECTOR first argument and LIST second
argument are improved.
- optimization: TYPECASE over a set of structure types known not to be
extensible is converted to an array lookup.
New in version 2.5.6, 2025-06-29
Back to top- enhancement: the compiler now recognizes when local functions (both named
and anonymous) are used only as downward funargs in many situations and
can stack allocate such closures even without explicit dynamic extent
declarations. See the updated manual entry on stack allocation for more
information and how user-code can declare funargs as downward.
- minor incompatible change: optimization notes for a variable declared to
be of type LIST will not be emitted for various transforms which are
defined to operate on (OR NULL VECTOR).
- minor incompatible change: some forms, including a THE form with an
invalid type specifier, or a CASE form with bad entries, no longer produce
a runtime error. (They continue to provide a full warning at
compile-time).
- platform support
- on arm64, breakpoint-based stepping is now thread-safe.
- on arm64, backtraces after interrupts should be more correct.
- on x86-64 with the immobile-space feature, calling from assembly
routines to lisp routines is more efficient.
- if arenas are enabled, users can define a lisp function to act as a
handler to customize behaviour on arena exhaustion.
- bug fix: address several bugs related to dynamic-extent declarations,
inference, and stack allocation.
- bug fix: the stack return page protection is temporarily disabled during
GC, so that GC can complete even if it needs to write in the return page.
- bug fix: the compiler generates code to the right entry point for specialized
functions. (#2111876, reported by Matt Kaufmann)
- bug fix: the compiler's constraint derivation would sometimes not terminate.
(#2113747)
- bug fix: when the runtime structure representing a thread is re-used, the
stack guard pages are restored.
- bug fix: type checks for &OPTIONAL arguments are done only once.
- bug fix: CEILING's docstring was wrong. (reported by Dave Tenny)
- bug fix: APPLY could be called with too many arguments when parsing MEMBER
type specifications. (reported by Zach Beane)
- bug fix: the compiler could allow constant values of bad types to trigger
optimizations. (#2113977)
- bug fix: internal compiler error when attempting to write out a type check
for a value already proved to never exist (i.e. be of type NIL).
(#2112475)
- optimization: better division for signed-word dividends and unsigned-word
divisors on arm64 and x86-64.
- optimization: improvements to subtraction involving bignums and words on
x86-64.
- optimization: perfect-hash-based transformations are applied to sequence
functions with keys including fixnums and characters as well as symbols.
