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CFG optimizer work in progress - adding phi nodes

db4
Slava Pestov 2009-05-21 16:49:28 -05:00
parent 30abf75f64
commit 6af61656f3
4 changed files with 92 additions and 28 deletions
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1
basis/compiler/cfg/def-use/def-use.factor
View File

@ -39,6 +39,7 @@ M: ##dispatch uses-vregs src>> 1array ;
M: ##alien-getter uses-vregs src>> 1array ;
M: ##alien-setter uses-vregs [ src>> ] [ value>> ] bi 2array ;
M: ##fixnum-overflow uses-vregs [ src1>> ] [ src2>> ] bi 2array ;
M: ##phi uses-vregs inputs>> ;
M: _conditional-branch uses-vregs [ src1>> ] [ src2>> ] bi 2array ;
M: _compare-imm-branch uses-vregs src1>> 1array ;
M: insn uses-vregs drop f ;

2
basis/compiler/cfg/hats/hats.factor
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@ -73,3 +73,5 @@ IN: compiler.cfg.hats
: ^^offset>slot ( vreg -- vreg' ) cell 4 = [ 1 ^^shr-imm ] when ; inline
: ^^tag-fixnum ( src -- dst ) ^^i1 ##tag-fixnum ; inline
: ^^untag-fixnum ( src -- dst ) ^^i1 ##untag-fixnum ; inline
: ^^phi ( inputs -- dst ) ^^i1 ##phi ; inline

2
basis/compiler/cfg/instructions/instructions.factor
View File

@ -178,6 +178,8 @@ INSN: ##branch ;
INSN: ##loop-entry ;
INSN: ##phi < ##pure inputs ;
! Condition codes
SYMBOL: cc<
SYMBOL: cc<=

115
basis/compiler/cfg/stack-analysis/stack-analysis.factor
View File

@ -1,9 +1,9 @@
! Copyright (C) 2009 Slava Pestov.
! See http://factorcode.org/license.txt for BSD license.
USING: accessors assocs kernel namespaces math sequences fry deques
USING: accessors assocs kernel namespaces math sequences fry deques grouping
search-deques dlists sets make combinators compiler.cfg.copy-prop
compiler.cfg.def-use compiler.cfg.instructions compiler.cfg.registers
compiler.cfg.rpo ;
compiler.cfg.rpo compiler.cfg.hats ;
IN: compiler.cfg.stack-analysis
! Convert stack operations to register operations
@ -67,10 +67,11 @@ M: state clone
[ vregs>locs>> clear-assoc ]
} cleave ;
ERROR: poisoned-state state ;
: sync-state ( -- )
! also: update height
! but first, sync outputs
state get {
[ dup poisoned?>> [ poisoned-state ] [ drop ] if ]
[ save-changed-locs ]
[ d-height>> dup 0 = [ drop ] [ ##inc-d ] if ]
[ r-height>> dup 0 = [ drop ] [ ##inc-r ] if ]
@ -181,11 +182,72 @@ SYMBOL: work-list
! Maps basic-blocks to states
SYMBOLS: state-in state-out ;
: merge-states ( seq -- state )
[ <state> ] [ first ] if-empty ;
: sync-unpoisoned-states ( predecessors states -- )
[
dup poisoned?>> [ 2drop ] [
state [
instructions>> building set
sync-state
] with-variable
] if
] 2each ;
ERROR: must-equal-failed seq ;
: must-equal ( seq -- elt )
dup all-equal? [ first ] [ must-equal-failed ] if ;
: merge-heights ( state predecessors states -- state )
nip
[ [ d-height>> ] map must-equal >>d-height ]
[ [ r-height>> ] map must-equal >>r-height ] bi ;
ERROR: inconsistent-vreg>loc states ;
: check-vreg>loc ( states -- )
! The same vreg should not store different locs in
! different branches
dup
[ vregs>locs>> ] map
[ [ keys ] map concat prune ] keep
'[ _ [ at ] with map sift all-equal? ] all?
[ drop ] [ inconsistent-vreg>loc ] if ;
: insert-peek ( predecessor loc -- vreg )
! XXX critical edges
[ instructions>> building ] dip '[ _ ^^peek ] with-variable ;
: 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
^^phi ;
: merge-locs ( state predecessors states -- state )
[ locs>vregs>> ] map dup [ keys ] map prune
[
[ 2nip ] [ merge-loc ] 3bi
] with with H{ } map>assoc
>>locs>vregs ;
: merge-states ( predecessors states -- state )
! If any states are poisoned, save all registers
! to the stack in each branch
[ drop <state> ] [
dup [ poisoned?>> ] any? [
sync-unpoisoned-states <state>
] [
dup check-vreg>loc
[ state new ] 2dip
[ merge-heights ]
[ merge-locs ] 2bi
! what about vregs>locs
] if
] if-empty ;
: block-in-state ( bb -- states )
predecessors>> state-out get '[ _ at ] map merge-states ;
predecessors>> dup state-out get '[ _ at ] map merge-states ;
: maybe-set-at ( value key assoc -- changed? )
3dup at* [ = [ 3drop f ] [ set-at t ] if ] [ 2drop set-at t ] if ;
@ -201,14 +263,19 @@ SYMBOLS: state-in state-out ;
[ successors>> [ add-to-work-list ] each ] [ drop ] if ;
: visit-block ( bb -- )
dup block-in-state
[ swap set-block-in-state ] [
state [
[ [ [ [ visit ] each ] V{ } make ] change-instructions drop ]
[ state get finish-block ]
bi
] with-variable
] 2bi ;
! block-in-state may add phi nodes at the start of the basic block
! so we wrap the whole thing with a 'make'
[
dup block-in-state
[ swap set-block-in-state ] [
state [
[ instructions>> [ visit ] each ]
[ state get finish-block ]
[ ]
tri
] with-variable
] 2bi
] V{ } make >>instructions drop ;
: visit-blocks ( bb -- )
reverse-post-order work-list get
@ -223,16 +290,8 @@ SYMBOLS: state-in state-out ;
dup entry>> visit-blocks
] with-scope ;
! To do:
! - implement merge-states
! - insert loads to convert partially available values into available values
! if any state is poisoned, then we need to sync in every predecessor that didn't sync
! and begin with a new state.
! if heights differ, throw an error.
! changed-locs is the union of the changed-locs of all predecessors
! locs>vregs: take the union, then for each predecessor, diff its locs>vregs against the union.
! those are the ones that need to be loaded in.
! think about phi insertion.
! XXX: what if our height doesn't match
! a future block we're merging with?
! - we should only poison tail calls
! - non-tail poisoning nodes: ##alien-callback, ##call of a non-tail dispatch
! do we need a distinction between height changes in code and height changes done by the callee