X-Git-Url: http://repo.macrolet.net/gitweb/?a=blobdiff_plain;f=base-target-features.lisp-expr;h=5aa58f73a9f9f768c22de08febd5c395fcfc2fc6;hb=d45e8a2e9167150c8283783152d2449bd8d59d2d;hp=8f169b8ced87ec9162593a217825424bb1223edf;hpb=993d5b779638756473181dda8d928d33038d4cc3;p=sbcl.git diff --git a/base-target-features.lisp-expr b/base-target-features.lisp-expr index 8f169b8..5aa58f7 100644 --- a/base-target-features.lisp-expr +++ b/base-target-features.lisp-expr @@ -2,6 +2,21 @@ ;;;; CL:*FEATURES* in the target SBCL, plus some comments about other ;;;; CL:*FEATURES* tags which have special meaning to SBCL or which ;;;; have a special conventional meaning +;;;; +;;;; 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: +;;;; (lambda (list) +;;;; (flet ((enable (x) (pushnew 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. ;;;; This software is part of the SBCL system. See the README file for ;;;; more information. @@ -25,7 +40,7 @@ :sbcl ;; Douglas Thomas Crosher's conservative generational GC (the only one - ;; we currently support) + ;; we currently support for X86) :gencgc ;; We're running under a UNIX. This is sort of redundant, and it was also @@ -74,6 +89,31 @@ ;; you are a developer. :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 + ;; Setting this makes more debugging information available. ;; If you aren't hacking or troubleshooting SBCL itself, you ;; probably don't want this set. @@ -99,6 +139,13 @@ ;; readtable configured so that the system sources can be read. ; :sb-show + ;; 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. + ; :sb-after-xc-core + ;; Enable extra debugging output in the assem.lisp assembler/scheduler ;; code. (This is the feature which was called :DEBUG in the ;; original CMU CL code.) @@ -143,49 +190,19 @@ ; :mp ; :mp-i486 - ;; KLUDGE: used to suppress stale code related to floating point infinities. - ;; I intend to delete this code completely some day, since it was a pain - ;; for me to try to work with and since all benefits it provides are - ;; non-portable. Until I actually pull the trigger, though, I've left - ;; various stale code in place protected with #!-SB-INFINITIES. - ; :sb-infinities - ;; 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. + ;; 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. + ;; This is probably true for some processor types, but not X86. It + ;; affects a lot of floating point code. ; :negative-zero-is-not-zero - ;; This is mentioned in cmu-user.tex, which says that it enables - ;; the compiler to reason about integer arithmetic. It also seems to - ;; control other fancy numeric reasoning, e.g. knowing the result type of - ;; a remainder calculation given the type of its inputs. - ;; - ;; CROSS-FLOAT-INFINITY-KLUDGE: The :PROPAGATE-FLOAT-TYPE and - ;; :PROPAGATE-FUN-TYPE features are problematic when building - ;; the cross-compiler itself. Their implementation depends on - ;; floating point infinities, which might not be supported in the - ;; cross-compilation host. In order to avoid this problem, while - ;; still supporting these features in the target Lisp compiler, - ;; we use the :WILL-PROPAGATE-FLOAT-TYPE feature when building - ;; the cross-compiler, and munge it into :PROPAGATE-FLOAT-TYPE - ;; only when building the target compiler; and similarly for - ;; :WILL-PROPAGATE-FUN-TYPE. - ;:will-propagate-float-type ; (becomes :PROPAGATE-FLOAT-TYPE) - - ;; According to cmu-user.tex, this enables the compiler to infer result - ;; types for mathematical functions like SQRT, EXPT, and LOG, allowing - ;; it to e.g. eliminate the possibility that a complex result will be - ;; generated. This applies only to the target compiler, not the - ;; cross-compiler: see CROSS-FLOAT-INFINITY-KLUDGE. - ;:will-propagate-fun-type ; (becomes :PROPAGATE-FUN-TYPE) - - ;; It's unclear to me what this does (but it was enabled in the code that I - ;; picked up from Peter Van Eynde). -- WHN 19990224 - :constrain-float-type + ;; 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 @@ -238,9 +255,6 @@ ;; phase of cross-compilation bootstrapping, when the cross-compiler is ;; being used to create the first target Lisp. - ;; notes on the :PROPAGATE-FLOAT-TYPE and :PROPAGATE-FUN-TYPE - ;; features: See the comments on CROSS-FLOAT-INFINITY-KLUDGE. - ;; notes on the :SB-ASSEMBLING feature (which isn't controlled by ;; this file): ;; @@ -254,14 +268,18 @@ ;; really, really know what you're doing): ;; ;; machine architecture features: - ;; :x86 ; any Intel 386 or better, or compatibles like the AMD K6 or K7 - ;; (No others are supported by SBCL as of 0.6.7, but :alpha or - ;; :sparc support could be ported from CMU CL if anyone is - ;; sufficiently motivated to do so.) - ;; (CMU CL also had a :pentium feature, which affected the definition - ;; of some floating point vops. It was present but not enabled in the - ;; CMU CL code that SBCL is derived from, and is present but stale - ;; in SBCL as of 0.6.7.) + ;; :x86 + ;; any Intel 386 or better, or compatibles like the AMD K6 or K7 + ;; :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.) + ;; (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.) ;; ;; operating system features: ;; :linux = We're intended to run under some version of Linux. @@ -272,5 +290,6 @@ ;; :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.) + ;; sufficiently motivated to do so, and it'd even be possible, + ;; though harder, to port the system to Microsoft Windows.) )