factor/basis/compiler/cfg/linear-scan/assignment/assignment.factor

88 lines
2.6 KiB
Factor

! Copyright (C) 2008 Slava Pestov.
! See http://factorcode.org/license.txt for BSD license.
USING: accessors kernel math assocs namespaces sequences heaps
fry make combinators
cpu.architecture
compiler.cfg.def-use
compiler.cfg.registers
compiler.cfg.instructions
compiler.cfg.linear-scan.live-intervals ;
IN: compiler.cfg.linear-scan.assignment
! A vector of live intervals. There is linear searching involved
! but since we never have too many machine registers (around 30
! at most) and we probably won't have that many live at any one
! time anyway, it is not a problem to check each element.
SYMBOL: active-intervals
: add-active ( live-interval -- )
active-intervals get push ;
: lookup-register ( vreg -- reg )
active-intervals get [ vreg>> = ] with find nip reg>> ;
! Minheap of live intervals which still need a register allocation
SYMBOL: unhandled-intervals
: add-unhandled ( live-interval -- )
dup split-before>> [
[ split-before>> ] [ split-after>> ] bi
[ add-unhandled ] bi@
] [
dup start>> unhandled-intervals get heap-push
] if ;
: init-unhandled ( live-intervals -- )
[ add-unhandled ] each ;
: insert-spill ( live-interval -- )
[ reg>> ] [ vreg>> reg-class>> ] [ spill-to>> ] tri
dup [ _spill ] [ 3drop ] if ;
: expire-old-intervals ( n -- )
active-intervals get
swap '[ end>> _ = ] partition
active-intervals set
[ insert-spill ] each ;
: insert-reload ( live-interval -- )
[ reg>> ] [ vreg>> reg-class>> ] [ reload-from>> ] tri
dup [ _reload ] [ 3drop ] if ;
: activate-new-intervals ( n -- )
#! Any live intervals which start on the current instruction
#! are added to the active set.
unhandled-intervals get dup heap-empty? [ 2drop ] [
2dup heap-peek drop start>> = [
heap-pop drop [ add-active ] [ insert-reload ] bi
activate-new-intervals
] [ 2drop ] if
] if ;
GENERIC: (assign-registers) ( insn -- )
M: vreg-insn (assign-registers)
dup
[ defs-vregs ] [ uses-vregs ] bi append
active-intervals get swap '[ vreg>> _ member? ] filter
[ [ vreg>> ] [ reg>> ] bi ] { } map>assoc
>>regs drop ;
M: insn (assign-registers) drop ;
: init-assignment ( live-intervals -- )
V{ } clone active-intervals set
<min-heap> unhandled-intervals set
init-unhandled ;
: assign-registers ( insns live-intervals -- insns' )
[
init-assignment
[
[ activate-new-intervals ]
[ drop [ (assign-registers) ] [ , ] bi ]
[ expire-old-intervals ]
tri
] each-index
] { } make ;