factor/basis/compiler/cfg/write-barrier/write-barrier.factor

47 lines
1.3 KiB
Factor

! Copyright (C) 2008, 2009 Slava Pestov.
! See http://factorcode.org/license.txt for BSD license.
USING: kernel accessors namespaces assocs sets sequences locals
compiler.cfg compiler.cfg.instructions compiler.cfg.copy-prop
compiler.cfg.liveness ;
IN: compiler.cfg.write-barrier
! Eliminate redundant write barrier hits.
! Objects which have already been marked, as well as
! freshly-allocated objects
SYMBOL: safe
! Objects which have been mutated
SYMBOL: mutated
GENERIC: eliminate-write-barrier ( insn -- insn' )
M: ##allot eliminate-write-barrier
dup dst>> safe get conjoin ;
M: ##write-barrier eliminate-write-barrier
dup src>> resolve dup
[ safe get key? not ]
[ mutated get key? ] bi and
[ safe get conjoin ] [ 2drop f ] if ;
M: ##copy eliminate-write-barrier
dup record-copy ;
M: ##set-slot eliminate-write-barrier
dup obj>> resolve mutated get conjoin ;
M: ##set-slot-imm eliminate-write-barrier
dup obj>> resolve mutated get conjoin ;
M: insn eliminate-write-barrier ;
: write-barriers-step ( insns -- insns' )
H{ } clone safe set
H{ } clone mutated set
H{ } clone copies set
[ eliminate-write-barrier ] map sift ;
: eliminate-write-barriers ( cfg -- cfg' )
[ drop ] [ write-barriers-step ] local-optimization ;