factor/basis/compiler/cfg/stack-analysis/merge/merge.factor

85 lines
2.5 KiB
Factor

! Copyright (C) 2009 Slava Pestov.
! See http://factorcode.org/license.txt for BSD license.
USING: kernel assocs sequences accessors fry combinators grouping
sets compiler.cfg compiler.cfg.hats
compiler.cfg.stack-analysis.state ;
IN: compiler.cfg.stack-analysis.merge
: initial-state ( bb states -- state ) 2drop <state> ;
: single-predecessor ( bb states -- state ) nip first clone ;
ERROR: must-equal-failed seq ;
: must-equal ( seq -- elt )
dup all-equal? [ first ] [ must-equal-failed ] if ;
: merge-heights ( state predecessors states -- state )
nip
[ [ ds-height>> ] map must-equal >>ds-height ]
[ [ rs-height>> ] map must-equal >>rs-height ] bi ;
: insert-peek ( predecessor loc -- vreg )
! XXX critical edges
'[ _ ^^peek ] add-instructions ;
: merge-loc ( predecessors locs>vregs loc -- vreg )
! Insert a ##phi in the current block where the input
! is the vreg storing loc from each predecessor block
[ '[ [ _ ] dip at ] map ] keep
'[ [ ] [ _ insert-peek ] ?if ] 2map
dup all-equal? [ first ] [ ^^phi ] if ;
: (merge-locs) ( predecessors assocs -- assoc )
dup [ keys ] map concat prune
[ [ 2nip ] [ merge-loc ] 3bi ] with with
H{ } map>assoc ;
: merge-locs ( state predecessors states -- state )
[ locs>vregs>> ] map (merge-locs) >>locs>vregs ;
: merge-actual-loc ( locs>vregs loc -- vreg )
'[ [ _ ] dip at ] map
dup all-equal? [ first ] [ drop f ] if ;
: merge-actual-locs ( state predecessors states -- state )
nip
[ actual-locs>vregs>> ] map
dup [ keys ] map concat prune
[ [ nip ] [ merge-actual-loc ] 2bi ] with
H{ } map>assoc
[ nip ] assoc-filter
>>actual-locs>vregs ;
: merge-changed-locs ( state predecessors states -- state )
nip [ changed-locs>> ] map assoc-combine >>changed-locs ;
ERROR: cannot-merge-poisoned states ;
: multiple-predecessors ( bb states -- state )
dup [ not ] any? [
[ <state> ] 2dip
sift merge-heights
] [
dup [ poisoned?>> ] any? [
cannot-merge-poisoned
] [
[ state new ] 2dip
[ predecessors>> ] dip
{
[ merge-locs ]
[ merge-actual-locs ]
[ merge-heights ]
[ merge-changed-locs ]
} 2cleave
] if
] if ;
: merge-states ( bb states -- state )
! If any states are poisoned, save all registers
! to the stack in each branch
dup length {
{ 0 [ initial-state ] }
{ 1 [ single-predecessor ] }
[ drop multiple-predecessors ]
} case ;