+;;;; -*- Lisp -*-
+
;;;; tags which are set during the build process and which end up in
;;;; CL:*FEATURES* in the target SBCL, plus some comments about other
;;;; CL:*FEATURES* tags which have special meaning to SBCL or which
;;;;
;;;; Note that the recommended way to customize the features of a
;;;; local build of SBCL is not to edit this file, but instead to
-;;;; tweak customize-target-features.lisp. E.g. you can use code like
-;;;; this:
+;;;; tweak customize-target-features.lisp. If you define a function
+;;;; in customize-target-features.lisp, it will be used to transform
+;;;; the target features list after it's read and before it's used.
+;;;; E.g. you can use code like this:
;;;; (lambda (list)
;;;; (flet ((enable (x) (pushnew x list))
-;;;; (disable (x) (setf list (remove x list))))
+;;;; (disable (x) (setf list (remove x list))))
;;;; #+nil (enable :sb-show)
;;;; (enable :sb-after-xc-core)
;;;; #+nil (disable :sb-doc)
;;;; list))
-;;;; That way, because customize-target-features.lisp is in
-;;;; .cvsignore, your local changes will remain local even if you use
-;;;; "cvs diff" to submit patches to SBCL.
+;;;; By thus editing a local file (one which is not in the source
+;;;; distribution, and which is in .cvsignore) your customizations
+;;;; will remain local even if you do things like "cvs update",
+;;;; will not show up if you try to submit a patch with "cvs diff",
+;;;; and might even stay out of the way if you use other non-CVS-based
+;;;; methods to upgrade the files or store your configuration.
;;;; This software is part of the SBCL system. See the README file for
;;;; more information.
;; our standard
:ansi-cl :common-lisp
;; FIXME: Isn't there a :x3jsomething feature which we should set too?
+ ;; No. CLHS says ":x3j13 [...] A conforming implementation might or
+ ;; might not contain such a feature." -- CSR, 2002-02-21
;; our dialect
:sbcl
;; Douglas Thomas Crosher's conservative generational GC (the only one
- ;; we currently support for X86)
- :gencgc
+ ;; we currently support for X86).
+ ;; :gencgc used to be here; CSR moved it into
+ ;; local-target-features.lisp-expr via make-config.sh, as alpha,
+ ;; sparc and ppc ports don't currently support it. -- CSR, 2002-02-21
;; We're running under a UNIX. This is sort of redundant, and it was also
;; sort of redundant under CMU CL, which we inherited it from: neither SBCL
;; the executable I'm running.
:sb-doc
- ;; Do regression and other tests when building the system. You
- ;; might or might not want this if you're not a developer,
- ;; depending on how paranoid you are. You probably do want it if
- ;; you are a developer.
+ ;; Do regression and other tests when building the system. You might
+ ;; or might not want this if you're not a developer, depending on how
+ ;; paranoid you are. You probably do want it if you are a developer.
+ ;; This test does not affect the target system (in much the same way
+ ;; as :sb-after-xc-core, below).
:sb-test
- ;; :SB-PROPAGATE-FLOAT-TYPE and :SB-PROPAGATE-FUN-TYPE enable
- ;; some numeric optimizer code in the target compiler. They
- ;; correspond to the :PROPAGATE-FLOAT-TYPE and :PROPAGATE-FUN-TYPE
- ;; features in the original CMU CL code, and while documentation
- ;; existed for those, it seemed a little inconsistent. Despite the
- ;; name, :SB-PROPAGATE-FLOAT-TYPE seems to control not only
- ;; floating point optimizations, but some integer optimizations as
- ;; well.
- ;;
- ;; CROSS-FLOAT-INFINITY-KLUDGE:
- ;; * Even when these target features are enabled, the optimizations
- ;; aren't enabled in the cross-compiler, because some of them
- ;; depend on floating point infinities, which aren't in general
- ;; supported on the cross-compilation host.
- ;; * This is supported by hacking the features out of the
- ;; *SHEBANG-FEATURES* list while we're building the cross-compiler.
- ;; This is ugly and confusing and weird, but all the alternatives
- ;; that I could think of seem messy and error-prone. That doesn't
- ;; mean there's not a better way, though. Suggestions are welcome;
- ;; or if you'd like to submit patches to make this code work
- ;; without requiring floating point infinities, so that the entire
- ;; problem goes away, that might be even better! -- WHN 2001-03-22
- :sb-propagate-float-type
- :sb-propagate-fun-type
-
;; Make more debugging information available (for debugging SBCL
;; itself). If you aren't hacking or troubleshooting SBCL itself,
;; you probably don't want this set.
;; readtable configured so that the system sources can be read.
; :sb-show
- ;; Build SBCL with the old CMU CL low level debugger, "ldb". If
- ;; are aren't messing with CMU CL at a very low level (e.g.
- ;; trying to diagnose GC problems) you shouldn't need this.
+ ;; Build SBCL with the old CMU CL low level debugger, "ldb". If are
+ ;; aren't messing with SBCL at a very low level (e.g., trying to
+ ;; diagnose GC problems, or trying to debug assembly code for a port
+ ;; to a new CPU) you shouldn't need this.
; :sb-ldb
;; This isn't really a target Lisp feature at all, but controls
;; whether the build process produces an after-xc.core file. This
- ;; can be useful for shortening the edit/compile/debug cycle if
- ;; you're messing around with low-level internals of the system,
- ;; as in slam.sh. Otherwise you don't need it.
+ ;; can be useful for shortening the edit/compile/debug cycle when
+ ;; you modify SBCL's own source code, as in slam.sh. Otherwise
+ ;; you don't need it.
; :sb-after-xc-core
;; Enable extra debugging output in the assem.lisp assembler/scheduler
;; anyone who wants to collect such statistics in the future.
; :sb-dyncount
- ;; Peter Van Eynde's increase-bulletproofness code
+ ;; Peter Van Eynde's increase-bulletproofness code for CMU CL
;;
- ;; This is not maintained or tested in current SBCL, but I haven't
- ;; gone out of my way to remove or break it, either.
+ ;; Some of the code which was #+high-security before the fork has now
+ ;; been either made unconditional, deleted, or rewritten into
+ ;; unrecognizability, but some remains. What remains is not maintained
+ ;; or tested in current SBCL, but I haven't gone out of my way to
+ ;; break it, either.
;;
; :high-security
; :high-security-support
- ;; multiprocessing support
+ ;; low-level thread primitives support
;;
- ;; This is not maintained or tested in current SBCL. I haven't gone out
- ;; of my way to break it, but since it's derived from an old version of
- ;; CMU CL where multiprocessing was pretty shaky, it's likely to be very
- ;; flaky now.
- ;; :MP enables multiprocessing
- ;; :MP-I486 is used, only within the multiprocessing code, to control
- ;; what seems to control processor-version-specific code. It's
- ;; probably for 486 or later, i.e. could be set as long as
- ;; you know you're not running on a 386, but it doesn't seem
- ;; to be documented anywhere, so that's just a guess.
- ; :mp
- ; :mp-i486
+ ;; As of SBCL 0.8, this is only supposed to work in x86 Linux with
+ ;; NPTL support (usually kernel 2.6, though sme Red Hat distributions
+ ;; with older kernels also have it) and is implemented using clone(2)
+ ;; and the %fs segment register. Note that no consistent effort to
+ ;; audit the SBCL library code for thread safety has been performed,
+ ;; so caveat executor.
+ ; :sb-thread
+
+ ;; Support for detection of unportable code (when applied to the
+ ;; COMMON-LISP package, or SBCL-internal pacakges) or bad-neighbourly
+ ;; code (when applied to user-level packages), relating to material
+ ;; alteration to packages or to bindings in symbols in packages.
+ :sb-package-locks
+
+ ;; Support for the entirety of the 21-bit character space defined by
+ ;; the Unicode consortium, rather than the classical 8-bit ISO-8859-1
+ ;; character set.
+ :sb-unicode
+
+ ;; Record source location information for variables, classes, conditions,
+ ;; packages, etc. Gives much better information on M-. in Slime, but
+ ;; increases core size by about 100kB.
+ :sb-source-locations
;; This affects the definition of a lot of things in bignum.lisp. It
;; doesn't seem to be documented anywhere what systems it might apply
;; to. It doesn't seem to be needed for X86 systems anyway.
; :32x16-divide
- ;; This is probably true for some processor types, but not X86. It
- ;; affects a lot of floating point code.
- ; :negative-zero-is-not-zero
-
- ;; It's unclear to me what this does (but it was enabled in the code
- ;; that I picked up from Peter Van Eynde, called CONSTRAIN-FLOAT-TYPE
- ;; instead of SB-CONSTRAIN-FLOAT-TYPE). -- WHN 19990224
- :sb-constrain-float-type
-
;; This is set in classic CMU CL, and presumably there it means
;; that the floating point arithmetic implementation
;; conforms to IEEE's standard. Here it definitely means that the
;; the underlying x86 hardware tries).
:ieee-floating-point
- ;; This seems to be the pre-GENCGC garbage collector for CMU CL, which was
- ;; AFAIK never supported for the X86.
- ; :gengc
-
;; CMU CL had, and we inherited, code to support 80-bit LONG-FLOAT on the x86
;; architecture. Nothing has been done to actively destroy the long float
;; support, but it hasn't been thoroughly maintained, and needs at least
;; in the *FEATURES* list
;;
+ ;; Any target feature which affects binary compatibility of fasl files
+ ;; needs to be recorded in *FEATURES-POTENTIALLY-AFFECTING-FASL-FORMAT*
+ ;; (elsewhere).
+
;; notes on the :NIL and :IGNORE features:
;;
;; #+NIL is used to comment out forms. Occasionally #+IGNORE is used
;; notes on local features (which are set automatically by the
;; configuration script, and should not be set here unless you
;; really, really know what you're doing):
- ;;
+ ;;
;; machine architecture features:
;; :x86
;; any Intel 386 or better, or compatibles like the AMD K6 or K7
+ ;; :x86-64
+ ;; any x86-64 CPU running in 64-bit mode
;; :alpha
;; DEC/Compaq Alpha CPU
- ;; (No other CPUs are supported by SBCL as of 0.6.12.15, but SPARC or
- ;; PowerPC support could be ported from CMU CL if anyone is
- ;; sufficiently motivated to do so, or if you're *really* motivated,
- ;; you could write a port from scratch for a new CPU architecture.)
+ ;; :sparc
+ ;; any Sun UltraSPARC (possibly also non-Ultras -- currently untested)
+ ;; :ppc
+ ;; any PowerPC CPU
+ ;; :hppa
+ ;; any PA-RISC CPU
+ ;; :mips
+ ;; any MIPS CPU (in little-endian mode with :little-endian -- currently
+ ;; untested)
+ ;;
;; (CMU CL also had a :pentium feature, which affected the definition
- ;; of some floating point vops. It was present but not enabled or
- ;; documented in the CMU CL code that SBCL is derived from, and is
- ;; present but stale in SBCL as of 0.6.12.)
+ ;; of some floating point vops. It was present but not enabled or
+ ;; documented in the CMU CL code that SBCL is derived from, and has
+ ;; now been moved to the backend-subfeatures mechanism.)
+ ;;
+ ;; properties derived from the machine architecture
+ ;; :control-stack-grows-downward-not-upward
+ ;; On the X86, the Lisp control stack grows downward. On the
+ ;; other supported CPU architectures as of sbcl-0.7.1.40, the
+ ;; system stack grows upward.
+ ;; Note that there are other stack-related differences between the
+ ;; X86 port and the other ports. E.g. on the X86, the Lisp control
+ ;; stack coincides with the C stack, meaning that on the X86 there's
+ ;; stuff on the control stack that the Lisp-level debugger doesn't
+ ;; understand very well. As of sbcl-0.7.1.40 things like that are
+ ;; just parameterized by #!+X86, but it'd probably be better to
+ ;; use new flags like :CONTROL-STACK-CONTAINS-C-STACK.
+ ;;
+ ;; :stack-allocatable-closures
+ ;; The compiler can allocate dynamic-extent closures on stack.
+ ;;
+ ;; :alien-callbacks
+ ;; Alien callbacks have been implemented for this platform.
;;
;; operating system features:
;; :linux = We're intended to run under some version of Linux.
;; is not exclusive with the features which indicate which
;; particular version of BSD we're intended to run under.)
;; :freebsd = We're intended to run under FreeBSD.
- ;; :openbsd = We're intended to run under FreeBSD.
- ;; (No others are supported by SBCL as of 0.6.7, but :hpux or
- ;; :solaris support could be ported from CMU CL if anyone is
- ;; sufficiently motivated to do so, and it'd even be possible,
- ;; though harder, to port the system to Microsoft Windows.)
+ ;; :openbsd = We're intended to run under OpenBSD.
+ ;; :netbsd = We're intended to run under NetBSD.
+ ;; :darwin = We're intended to run under Darwin (including MacOS X).
+ ;; :sunos = We're intended to run under Solaris user environment
+ ;; with the SunOS kernel.
+ ;; :osf1 = We're intended to run under Tru64 (aka Digital Unix
+ ;; aka OSF/1).
+ ;; (No others are supported by SBCL as of 0.9.6, but :hpux or :irix
+ ;; support could be ported from CMU CL if anyone is sufficiently
+ ;; motivated to do so, and it'd even be possible, though harder, to
+ ;; port the system to Microsoft Windows.)
)