factor/basis/compiler/cfg/liveness/liveness.factor

112 lines
3.1 KiB
Factor

! Copyright (C) 2009, 2010 Slava Pestov.
! See http://factorcode.org/license.txt for BSD license.
USING: kernel accessors assocs fry deques dlists namespaces
sequences sets compiler.cfg compiler.cfg.def-use
compiler.cfg.instructions compiler.cfg.registers
compiler.cfg.utilities compiler.cfg.predecessors
compiler.cfg.rpo cpu.architecture ;
FROM: namespaces => set ;
IN: compiler.cfg.liveness
! See http://en.wikipedia.org/wiki/Liveness_analysis
SYMBOL: live-ins
: live-in ( bb -- set )
live-ins get at ;
SYMBOL: live-outs
: live-out ( bb -- set )
live-outs get at ;
! Assoc mapping basic blocks to sequences of sets of vregs; each
! sequence is in correspondence with a predecessor
SYMBOL: edge-live-ins
: edge-live-in ( predecessor basic-block -- set )
edge-live-ins get at at ;
GENERIC: visit-insn ( live-set insn -- live-set )
: kill-defs ( live-set insn -- live-set )
defs-vregs [ over delete-at ] each ; inline
: gen-uses ( live-set insn -- live-set )
uses-vregs [ over conjoin ] each ; inline
M: vreg-insn visit-insn [ kill-defs ] [ gen-uses ] bi ;
! Our liveness analysis annotates call sites with GC maps
! indicating the spill slots in the stack frame that contain
! tagged pointers, and thus have to be visited if a GC occurs
! inside the call.
: fill-gc-map ( live-set insn -- live-set )
representations get [
gc-map>> over keys
[ rep-of tagged-rep? ] filter
>>gc-roots
] when
drop ;
M: gc-map-insn visit-insn
[ kill-defs ] [ fill-gc-map ] [ gen-uses ] tri ;
M: ##phi visit-insn kill-defs ;
M: insn visit-insn drop ;
: transfer-liveness ( live-set instructions -- live-set' )
[ clone ] [ <reversed> ] bi* [ visit-insn ] each ;
: local-live-in ( instructions -- live-set )
[ H{ } ] dip transfer-liveness keys ;
SYMBOL: work-list
: add-to-work-list ( basic-blocks -- )
work-list get '[ _ push-front ] each ;
: compute-live-in ( basic-block -- live-in )
[ live-out ] keep instructions>> transfer-liveness ;
: compute-edge-live-in ( basic-block -- edge-live-in )
H{ } clone [
'[ inputs>> [ swap _ conjoin-at ] assoc-each ] each-phi
] keep ;
: update-live-in ( basic-block -- changed? )
[ [ compute-live-in ] keep live-ins get maybe-set-at ]
[ [ compute-edge-live-in ] keep edge-live-ins get maybe-set-at ]
bi or ;
: compute-live-out ( basic-block -- live-out )
[ successors>> [ live-in ] map ]
[ dup successors>> [ edge-live-in ] with map ] bi
append assoc-combine ;
: update-live-out ( basic-block -- changed? )
[ compute-live-out ] keep
live-outs get maybe-set-at ;
: liveness-step ( basic-block -- )
dup update-live-out [
dup update-live-in
[ predecessors>> add-to-work-list ] [ drop ] if
] [ drop ] if ;
: compute-live-sets ( cfg -- )
needs-predecessors
<hashed-dlist> work-list set
H{ } clone live-ins set
H{ } clone edge-live-ins set
H{ } clone live-outs set
post-order add-to-work-list
work-list get [ liveness-step ] slurp-deque ;
: live-in? ( vreg bb -- ? ) live-in key? ;
: live-out? ( vreg bb -- ? ) live-out key? ;