 ! Copyright (C) 2009 Slava Pestov.
 ! See http://factorcode.org/license.txt for BSD license.
 USING: kernel namespaces deques accessors sets sequences assocs fry
-dlists compiler.cfg.def-use ;
+dlists compiler.cfg.def-use compiler.cfg.instructions ;
 IN: compiler.cfg.liveness
 
 ! This is a backward dataflow analysis. See http://en.wikipedia.org/wiki/Liveness_analysis

: map-unique ( seq quot -- assoc )
    map concat unique ; inline

: gen-set ( basic-block -- seq )
    instructions>> [ uses-vregs ] map-unique ;

: kill-set ( basic-block -- seq )
    instructions>> [ defs-vregs ] map-unique ;

: update-live-in ( basic-block -- changed? )
    [
        [ [ gen-set ] [ live-out ] bi assoc-union ]
        [ kill-set ]
        bi assoc-diff
    ] keep live-ins get maybe-set-at ;

: update-live-out ( basic-block -- changed? )
    [ successors>> [ live-in ] map assoc-combine ] keep
    live-outs get maybe-set-at ;

: liveness-step ( basic-block -- )

SYMBOL: live-ins

: live-in ( basic-block -- set ) live-ins get at ;

! Assoc mapping basic blocks to sequences of sets of vregs; each sequence
! is in conrrespondence with a predecessor
SYMBOL: phi-live-ins

: phi-live-in ( predecessor basic-block -- set )
    [ predecessors>> index ] keep phi-live-ins get at
    dup [ nth ] [ 2drop f ] if ;

! Assoc mapping basic blocks to sets of vregs
SYMBOL: live-outs
