A first attempt at implementing Vivek Sarkar's algorithm for scheduling for register pressure

db4
Daniel Ehrenberg 2010-02-10 21:43:30 -06:00
parent ce11431fdb
commit 04946dcddd
3 changed files with 329 additions and 0 deletions

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@ -0,0 +1,180 @@
! Copyright (C) 2009, 2010 Daniel Ehrenberg.
! See http://factorcode.org/license.txt for BSD license.
USING: accessors assocs combinators compiler.cfg.def-use
compiler.cfg.instructions compiler.cfg.registers fry kernel
locals namespaces sequences sets sorting math.vectors
make math combinators.short-circuit ;
IN: compiler.cfg.dependence
! Dependence graph construction
SYMBOL: roots
SYMBOL: node-number
SYMBOL: nodes
! Nodes in the dependency graph
! These need to be numbered so that the same instruction
! will get distinct nodes if it occurs multiple times
TUPLE: node
number insn precedes follows
children parent
registers parent-index ;
M: node equal? [ number>> ] bi@ = ;
M: node hashcode* nip number>> ;
: <node> ( insn -- node )
node new
node-number counter >>number
swap >>insn
H{ } clone >>precedes
H{ } clone >>follows ;
: ready? ( node -- ? ) precedes>> assoc-empty? ;
: precedes ( first second -- )
swap precedes>> conjoin ;
:: add-data-edges ( nodes -- )
! This builds up def-use information on the fly, since
! we only care about local def-use
H{ } clone :> definers
nodes [| node |
node insn>> defs-vreg [ node swap definers set-at ] when*
node insn>> uses-vregs [ definers at [ node precedes ] when* ] each
] each ;
: make-chain ( nodes -- )
[ dup rest-slice [ precedes ] 2each ] unless-empty ;
: instruction-chain ( nodes quot -- )
'[ insn>> @ ] filter make-chain ; inline
UNION: stack-read-write ##peek ##replace ;
UNION: stack-change-height ##inc-d ##inc-r ;
UNION: stack-insn stack-read-write stack-change-height ;
GENERIC: data-stack-insn? ( insn -- ? )
M: object data-stack-insn? drop f ;
M: ##inc-d data-stack-insn? drop t ;
M: stack-read-write data-stack-insn? loc>> ds-loc? ;
: retain-stack-insn? ( insn -- ? )
dup stack-insn? [ data-stack-insn? not ] [ drop f ] if ;
UNION: ##alien-read
##alien-double ##alien-float ##alien-cell ##alien-vector
##alien-signed-1 ##alien-signed-2 ##alien-signed-4
##alien-unsigned-1 ##alien-unsigned-2 ##alien-unsigned-4 ;
UNION: ##alien-write
##set-alien-double ##set-alien-float ##set-alien-cell ##set-alien-vector
##set-alien-integer-1 ##set-alien-integer-2 ##set-alien-integer-4 ;
UNION: slot-memory-insn
##read ##write ;
UNION: alien-memory-insn
##alien-read ##alien-write ;
UNION: string-memory-insn
##string-nth ##set-string-nth-fast ;
UNION: alien-call-insn
##save-context ##alien-invoke ##alien-indirect ##alien-callback ;
: add-control-edges ( nodes -- )
{
[ [ data-stack-insn? ] instruction-chain ]
[ [ retain-stack-insn? ] instruction-chain ]
[ [ alien-memory-insn? ] instruction-chain ]
[ [ slot-memory-insn? ] instruction-chain ]
[ [ string-memory-insn? ] instruction-chain ]
[ [ alien-call-insn? ] instruction-chain ]
} cleave ;
: set-follows ( nodes -- )
[
dup precedes>> values [
follows>> conjoin
] with each
] each ;
: set-roots ( nodes -- )
[ ready? ] filter V{ } like roots set ;
: build-dependence-graph ( instructions -- )
[ <node> ] map {
[ add-data-edges ]
[ add-control-edges ]
[ set-follows ]
[ nodes set ] ! for assertions later
[ set-roots ]
} cleave ;
:: calculate-registers ( node -- registers )
node children>> [ 0 ] [
[ [ calculate-registers ] map natural-sort ]
[ length iota ]
bi v+ supremum
] if-empty
node insn>> temp-vregs length +
dup node (>>registers) ;
: data-dependence? ( to from -- ? )
! If this takes lots of time, then refactor code
! so that nodes store their data dependences
[ insn>> ] bi@
[ uses-vregs ] [ defs-vreg ] bi*
swap member? ;
DEFER: follow-tree
: maybe-cut-node ( node -- ? )
! If this node has multiple successors
! then it needs to be made into the head of a new tree
[ precedes>> assoc-size 1 = dup ] keep
'[ _ dup , follow-tree ] when ;
: follow-tree ( node -- )
! This is bogus: it misses nodes that aren't reachable
! from the roots because of a control dependence
dup dup follows>> values
[ data-dependence? ] with filter
[ parent>> not ] filter
[ maybe-cut-node ] filter
[ [ >>parent drop ] with each ]
[ >>children drop ] 2bi ;
ERROR: node-missing-parent trees nodes ;
ERROR: node-missing-children trees nodes ;
: flatten-tree ( node -- nodes )
[ children>> [ flatten-tree ] map concat ] keep
suffix ;
: verify-parents ( trees -- trees )
nodes get over '[ [ parent>> ] [ _ member? ] bi or ] all?
[ nodes get node-missing-parent ] unless ;
: verify-children ( trees -- trees )
dup [ flatten-tree ] map concat
nodes get
{ [ [ length ] bi@ = ] [ set= ] } 2&&
[ nodes get node-missing-children ] unless ;
: verify-trees ( trees -- trees )
verify-parents verify-children ;
: make-trees ( -- trees )
[
roots get [ dup , follow-tree ] each
] { } make verify-trees ;
: build-fan-in-trees ( -- )
make-trees [
-1/0. >>parent-index
calculate-registers drop
] each ;

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@ -11,6 +11,7 @@ compiler.cfg.value-numbering
compiler.cfg.copy-prop
compiler.cfg.dce
compiler.cfg.write-barrier
compiler.cfg.scheduling
compiler.cfg.representations
compiler.cfg.ssa.destruction
compiler.cfg.empty-blocks
@ -35,6 +36,7 @@ SYMBOL: check-optimizer?
copy-propagation
eliminate-dead-code
eliminate-write-barriers
schedule-instructions
select-representations
destruct-ssa
delete-empty-blocks

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! Copyright (C) 2009, 2010 Daniel Ehrenberg.
! See http://factorcode.org/license.txt for BSD license.
USING: accessors assocs combinators compiler.cfg.def-use
compiler.cfg.dependence compiler.cfg.instructions
compiler.cfg.registers compiler.cfg.rpo continuations
cpu.architecture fry hashtables kernel locals math math.order
namespaces random sequences sets vectors literals make
arrays
compiler.cfg.liveness
compiler.cfg.liveness.ssa ;
IN: compiler.cfg.scheduling
! Instruction scheduling to reduce register pressure, from:
! "Register-sensitive selection, duplication, and
! sequencing of instructions"
! by Vivek Sarkar, et al.
! http://portal.acm.org/citation.cfm?id=377849
ERROR: bad-delete-at key assoc ;
: check-delete-at ( key assoc -- )
2dup key? [ delete-at ] [ bad-delete-at ] if ;
: set-parent-indices ( node -- )
children>> building get length
'[ _ >>parent-index drop ] each ;
: remove-node ( node -- )
[ follows>> values ] keep
'[ [ precedes>> _ swap check-delete-at ] each ]
[ [ ready? ] filter roots get push-all ] bi ;
: score ( insn -- n )
[ parent-index>> ] [ registers>> neg ] bi 2array ;
: pull-out-nth ( n seq -- elt )
[ nth ] [ remove-nth! drop ] 2bi ;
: select ( vector quot -- elt )
! This could be sped up by a constant factor
[ dup <enum> ] dip '[ _ call( insn -- score ) ] assoc-map
dup values supremum '[ nip _ = ] assoc-find
2drop swap pull-out-nth ; inline
: select-instruction ( -- insn/f )
roots get [ f ] [
[ score ] select
[ insn>> ]
[ set-parent-indices ]
[ remove-node ] tri
] if-empty ;
: (reorder) ( -- )
select-instruction [
, (reorder)
] when* ;
: cut-by ( seq quot -- before after )
dupd find drop [ cut ] [ f ] if* ; inline
: split-3-ways ( insns -- first middle last )
[ ##phi? not ] cut-by unclip-last ;
: reorder ( insns -- insns' )
split-3-ways [
build-dependence-graph
build-fan-in-trees
[ (reorder) ] V{ } make reverse
] dip suffix append ;
ERROR: not-all-instructions-were-scheduled old-bb new-bb ;
SYMBOL: check-scheduling?
t check-scheduling? set-global
:: check-instructions ( new-bb old-bb -- )
new-bb old-bb [ instructions>> ] bi@
[ [ length ] bi@ = ] [ [ unique ] bi@ = ] 2bi and
[ old-bb new-bb not-all-instructions-were-scheduled ] unless ;
ERROR: definition-after-usage vreg old-bb new-bb ;
:: check-usages ( new-bb old-bb -- )
H{ } clone :> useds
new-bb instructions>> split-3-ways drop nip
[| insn |
insn uses-vregs [ useds conjoin ] each
insn defs-vreg :> def-reg
def-reg useds key?
[ def-reg old-bb new-bb definition-after-usage ] when
] each ;
: check-scheduling ( new-bb old-bb -- )
[ check-instructions ] [ check-usages ] 2bi ;
: with-scheduling-check ( bb quot: ( bb -- ) -- )
check-scheduling? get [
over dup clone
[ call( bb -- ) ] 2dip
check-scheduling
] [
call( bb -- )
] if ; inline
: number-insns ( insns -- )
[ >>insn# drop ] each-index ;
: clear-numbers ( insns -- )
[ f >>insn# drop ] each ;
: schedule-block ( bb -- )
[
[
[ number-insns ]
[ reorder ]
[ clear-numbers ] tri
] change-instructions drop
] with-scheduling-check ;
! Really, instruction scheduling should be aware that there are
! multiple types of registers, but this number is just used
! to decide whether to schedule instructions
: num-registers ( -- x ) int-regs machine-registers at length ;
: update-vregs ( insn vregs -- )
[ [ defs-vreg ] dip '[ _ delete-at ] when* ]
[ [ uses-vregs ] dip '[ _ conjoin ] each ] 2bi ;
:: (might-spill?) ( vregs insns -- ? )
insns <reversed> [
[ vregs update-vregs ]
[ temp-vregs length vregs assoc-size + num-registers > ] bi
] any? ;
: might-spill? ( bb -- ? )
! Conservative approximation testing whether a bb might spill
! by calculating register pressure all along, assuming
! everything in live-out are in registers
! This is done bottom-up: a def means the register is no longer live
[ live-out H{ } assoc-clone-like ] [ instructions>> ] bi (might-spill?) ;
: schedule-instructions ( cfg -- cfg' )
dup [
dup might-spill?
[ schedule-block ]
[ drop ] if
] each-basic-block ;