factor/unfinished/compiler/tree/dead-code/dead-code.factor

148 lines
3.8 KiB
Factor

! Copyright (C) 2008 Slava Pestov.
! See http://factorcode.org/license.txt for BSD license.
USING: fry accessors namespaces assocs dequeues search-dequeues
kernel sequences words sets stack-checker.inlining
compiler.tree
compiler.tree.dfa
compiler.tree.dfa.backward
compiler.tree.combinators ;
IN: compiler.tree.dead-code
! Dead code elimination: remove #push and flushable #call whose
! outputs are unused using backward DFA.
GENERIC: mark-live-values ( node -- )
M: #if mark-live-values look-at-inputs ;
M: #dispatch mark-live-values look-at-inputs ;
M: #call mark-live-values
dup word>> "flushable" word-prop
[ drop ] [ [ look-at-inputs ] [ look-at-outputs ] bi ] if ;
M: #return mark-live-values
#! Values returned by local #recursive functions can be
#! killed if they're unused.
dup label>> [ drop ] [ look-at-inputs ] if ;
M: node mark-live-values drop ;
SYMBOL: live-values
: live-value? ( value -- ? ) live-values get at ;
: compute-live-values ( node -- )
[ mark-live-values ] backward-dfa live-values set ;
GENERIC: remove-dead-values* ( node -- )
M: #introduce remove-dead-values*
[ [ live-value? ] filter ] change-values drop ;
M: #>r remove-dead-values*
dup out-r>> first live-value? [ { } >>out-r ] unless
dup in-d>> first live-value? [ { } >>in-d ] unless
drop ;
M: #r> remove-dead-values*
dup out-d>> first live-value? [ { } >>out-d ] unless
dup in-r>> first live-value? [ { } >>in-r ] unless
drop ;
M: #push remove-dead-values*
dup out-d>> first live-value? [ { } >>out-d ] unless
drop ;
: filter-corresponding-values ( in out -- in' out' )
zip live-values get '[ drop _ , key? ] assoc-filter unzip ;
: filter-live ( values -- values' )
[ live-value? ] filter ;
M: #shuffle remove-dead-values*
[ filter-live ] change-in-d
[ filter-live ] change-out-d
drop ;
M: #declare remove-dead-values*
[ [ drop live-value? ] assoc-filter ] change-declaration
drop ;
M: #copy remove-dead-values*
dup
[ in-d>> ] [ out-d>> ] bi
filter-corresponding-values
[ >>in-d ] [ >>out-d ] bi*
drop ;
: remove-dead-phi-d ( #phi -- #phi )
dup
[ phi-in-d>> ] [ out-d>> ] bi
filter-corresponding-values
[ >>phi-in-d ] [ >>out-d ] bi* ;
: remove-dead-phi-r ( #phi -- #phi )
dup
[ phi-in-r>> ] [ out-r>> ] bi
filter-corresponding-values
[ >>phi-in-r ] [ >>out-r ] bi* ;
M: #phi remove-dead-values*
remove-dead-phi-d
remove-dead-phi-r
drop ;
M: node remove-dead-values* drop ;
M: f remove-dead-values* drop ;
GENERIC: remove-dead-nodes* ( node -- newnode/t )
: prune-if-empty ( node seq -- successor/t )
empty? [ successor>> ] [ drop t ] if ; inline
M: #introduce remove-dead-nodes* dup values>> prune-if-empty ;
: live-call? ( #call -- ? )
out-d>> [ live-value? ] contains? ;
M: #declare remove-dead-nodes* dup declaration>> prune-if-empty ;
M: #call remove-dead-nodes*
dup live-call? [ drop t ] [
[ in-d>> #drop ] [ successor>> ] bi >>successor
] if ;
M: #shuffle remove-dead-nodes* dup in-d>> prune-if-empty ;
M: #push remove-dead-nodes* dup out-d>> prune-if-empty ;
M: #>r remove-dead-nodes* dup in-d>> prune-if-empty ;
M: #r> remove-dead-nodes* dup in-r>> prune-if-empty ;
M: #copy remove-dead-nodes* dup in-d>> prune-if-empty ;
: (remove-dead-code) ( node -- newnode )
[
dup remove-dead-values*
dup remove-dead-nodes* dup t eq?
[ drop ] [ nip (remove-dead-code) ] if
] transform-nodes ;
M: #if remove-dead-nodes*
[ (remove-dead-code) ] map-children t ;
M: #dispatch remove-dead-nodes*
[ (remove-dead-code) ] map-children t ;
M: #recursive remove-dead-nodes*
[ (remove-dead-code) ] change-child drop t ;
M: node remove-dead-nodes* drop t ;
M: f remove-dead-nodes* drop t ;
: remove-dead-code ( node -- newnode )
[ [ compute-live-values ] [ (remove-dead-code) ] bi ] with-scope ;