factor/library/inference/kill-literals.factor

90 lines
2.5 KiB
Factor

! Copyright (C) 2004, 2005 Slava Pestov.
! See http://factor.sf.net/license.txt for BSD license.
IN: optimizer
USING: arrays generic hashtables inference kernel math
namespaces sequences ;
: node-union ( node quot -- hash | quot: node -- )
[
swap [ swap call [ dup set ] each ] each-node-with
] make-hash ; inline
GENERIC: literals* ( node -- seq )
: literals ( node -- hash )
[ literals* ] node-union ;
GENERIC: live-values* ( node -- seq )
: live-values ( node -- hash )
#! All values that are returned or passed to calls.
[ live-values* ] node-union ;
GENERIC: returns* ( node -- )
: returns ( node -- seq )
#! Trace all control flow paths, build a hash of
#! final #return nodes.
[ returns* ] { } make ;
M: f returns* drop ;
: kill-set ( node -- hash )
#! Push a list of literals that may be killed in the IR.
dup live-values swap literals hash-diff ;
: remove-values ( values node -- )
2dup [ node-in-d remove-all ] keep set-node-in-d
2dup [ node-out-d remove-all ] keep set-node-out-d
2dup [ node-in-r remove-all ] keep set-node-in-r
[ node-out-r remove-all ] keep set-node-out-r ;
: kill-node ( values node -- )
over hash-empty?
[ 2drop ] [ [ remove-values ] each-node-with ] if ;
! Generic nodes
M: node literals* ( node -- ) drop { } ;
M: node live-values* ( node -- ) node-values ;
M: node returns* ( node -- seq ) node-successor returns* ;
! #shuffle
M: #shuffle literals* ( node -- seq )
dup node-out-d swap node-out-r
[ [ literal? ] subset ] 2apply append ;
! #return
M: #return returns* , ;
M: #return live-values* ( node -- seq )
#! Values returned by local labels can be killed.
dup node-param [ drop { } ] [ delegate live-values* ] if ;
! nodes that don't use their input values directly
UNION: #killable #shuffle #call-label #merge #values #entry ;
M: #killable live-values* ( node -- seq ) drop { } ;
: purge-invariants ( stacks -- seq )
#! Output a sequence of values which are not present in the
#! same position in each sequence of the stacks sequence.
unify-lengths flip [ all-eq? not ] subset concat ;
! #label
M: #label live-values* ( node -- seq )
dup node-child node-in-d
>r collect-recursion r> add purge-invariants ;
! branching
UNION: #branch #if #dispatch ;
M: #branch returns* ( node -- ) node-children [ returns* ] each ;
M: #branch live-values* ( node -- )
#! This assumes that the last element of each branch is a
#! #return node.
dup delegate live-values*
>r returns [ node-in-d ] map purge-invariants r> append ;