77 lines
2.1 KiB
Factor
77 lines
2.1 KiB
Factor
! Copyright (C) 2009 Slava Pestov.
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! See http://factorcode.org/license.txt for BSD license.
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USING: kernel sequences byte-arrays namespaces accessors classes math
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math.order fry arrays combinators compiler.cfg.registers
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compiler.cfg.instructions compiler.cfg.dataflow-analysis ;
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IN: compiler.cfg.stacks.uninitialized
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! Uninitialized stack location analysis.
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! Consider the following sequence of instructions:
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! ##inc-d 2
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! _gc
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! ##replace ... D 0
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! ##replace ... D 1
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! The GC check runs before stack locations 0 and 1 have been initialized,
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! and it needs to zero them out so that GC doesn't try to trace them.
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<PRIVATE
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GENERIC: visit-insn ( insn -- )
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: handle-inc ( n symbol -- )
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[
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swap {
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{ [ dup 0 < ] [ neg short tail ] }
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{ [ dup 0 > ] [ <byte-array> prepend ] }
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} cond
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] change ;
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M: ##inc-d visit-insn n>> ds-loc handle-inc ;
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M: ##inc-r visit-insn n>> rs-loc handle-inc ;
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ERROR: uninitialized-peek insn ;
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M: ##peek visit-insn
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dup loc>> [ n>> ] [ class get ] bi ?nth 0 =
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[ uninitialized-peek ] [ drop ] if ;
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M: ##replace visit-insn
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loc>> [ n>> ] [ class get ] bi
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2dup length < [ [ 1 ] 2dip set-nth ] [ 2drop ] if ;
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M: insn visit-insn drop ;
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: prepare ( pair -- )
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[ first2 [ [ clone ] [ B{ } ] if* ] bi@ ] [ B{ } B{ } ] if*
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[ ds-loc set ] [ rs-loc set ] bi* ;
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: visit-block ( bb -- ) instructions>> [ visit-insn ] each ;
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: finish ( -- pair ) ds-loc get rs-loc get 2array ;
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: (join-sets) ( seq1 seq2 -- seq )
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2dup [ length ] bi@ max '[ _ 1 pad-tail ] bi@ [ bitand ] 2map ;
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: (uninitialized-locs) ( seq quot -- seq' )
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[ dup length [ drop 0 = ] pusher [ 2each ] dip ] dip map ; inline
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PRIVATE>
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FORWARD-ANALYSIS: uninitialized
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M: uninitialized-analysis transfer-set ( pair bb analysis -- pair' )
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drop [ prepare ] dip visit-block finish ;
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M: uninitialized-analysis join-sets ( sets analysis -- pair )
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2drop sift [ f ] [ [ ] [ [ (join-sets) ] 2map ] map-reduce ] if-empty ;
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: uninitialized-locs ( bb -- locs )
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uninitialized-in dup [
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first2
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[ [ <ds-loc> ] (uninitialized-locs) ]
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[ [ <rs-loc> ] (uninitialized-locs) ]
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bi* append
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] when ;
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