! Copyright (C) 2009, 2011 Slava Pestov.
-! See http://factorcode.org/license.txt for BSD license.
-USING: accessors arrays assocs fry locals kernel make
-namespaces sequences sequences.deep
-sets vectors
-cpu.architecture
-compiler.cfg.rpo
-compiler.cfg.def-use
-compiler.cfg.registers
-compiler.cfg.dominance
-compiler.cfg.instructions
-compiler.cfg.liveness
-compiler.cfg.ssa.cssa
-compiler.cfg.ssa.interference
-compiler.cfg.ssa.interference.live-ranges
-compiler.cfg.parallel-copy
-compiler.cfg.utilities
-compiler.utilities ;
-FROM: namespaces => set ;
+! See https://factorcode.org/license.txt for BSD license.
+USING: accessors assocs compiler.cfg.def-use compiler.cfg.dominance
+compiler.cfg.instructions compiler.cfg.liveness
+compiler.cfg.parallel-copy compiler.cfg.rpo compiler.cfg.ssa.cssa
+compiler.cfg.ssa.destruction.coalescing compiler.cfg.ssa.destruction.leaders
+compiler.cfg.ssa.interference.live-ranges compiler.cfg.utilities
+kernel make sequences namespaces ;
IN: compiler.cfg.ssa.destruction
-! Because of the design of the register allocator, this pass
-! has three peculiar properties.
-!
-! 1) Instead of renaming vreg usages in the CFG, a map from
-! vregs to canonical representatives is computed. This allows
-! the register allocator to use the original SSA names to get
-! reaching definitions.
-! 2) Useless ##copy instructions, and all ##phi instructions,
-! are eliminated, so the register allocator does not have to
-! remove any redundant operations.
-! 3) This pass computes live sets and fills out GC maps with
-! compiler.cfg.liveness, so the linear scan register allocator
-! does not need to compute liveness again.
-
-SYMBOL: leader-map
-
-: leader ( vreg -- vreg' ) leader-map get compress-path ;
-
-! Maps leaders to equivalence class elements.
-SYMBOL: class-element-map
-
-: class-elements ( vreg -- elts ) class-element-map get at ;
-
<PRIVATE
-! Sequence of vreg pairs
-SYMBOL: copies
-
-: value-of ( vreg -- value )
- dup insn-of dup ##tagged>integer? [ nip src>> ] [ drop ] if ;
-
-: init-coalescing ( -- )
- defs get
- [ [ drop dup ] assoc-map leader-map set ]
- [ [ [ dup dup value-of ] dip <vreg-info> 1array ] assoc-map class-element-map set ] bi
- V{ } clone copies set ;
-
-: coalesce-leaders ( vreg1 vreg2 -- )
- ! leader2 becomes the leader.
- swap leader-map get set-at ;
-
-: coalesce-elements ( merged vreg1 vreg2 -- )
- ! delete leader1's class, and set leader2's class to merged.
- class-element-map get [ delete-at ] [ set-at ] bi-curry bi* ;
-
-: coalesce-vregs ( merged leader1 leader2 -- )
- [ coalesce-leaders ] [ coalesce-elements ] 2bi ;
-
-GENERIC: prepare-insn ( insn -- )
-
-: maybe-eliminate-copy-later ( dst src -- )
- 2array copies get push ;
-
-M: insn prepare-insn drop ;
-
-M: alien-call-insn prepare-insn drop ;
-
-M: vreg-insn prepare-insn
- [ temp-vregs [ leader-map get conjoin ] each ]
- [
- [ defs-vregs ] [ uses-vregs ] bi
- 2dup [ empty? not ] both? [
- [ first ] bi@
- 2dup [ rep-of reg-class-of ] bi@ eq?
- [ maybe-eliminate-copy-later ] [ 2drop ] if
- ] [ 2drop ] if
- ] bi ;
-
-M: ##copy prepare-insn
- [ dst>> ] [ src>> ] bi maybe-eliminate-copy-later ;
-
-M: ##parallel-copy prepare-insn
- values>> [ first2 maybe-eliminate-copy-later ] each ;
-
-: leaders ( vreg1 vreg2 -- vreg1' vreg2' )
- [ leader ] bi@ ;
-
-: vregs-interfere? ( vreg1 vreg2 -- merged/f ? )
- [ class-elements ] bi@ sets-interfere? ;
-
-ERROR: vregs-shouldn't-interfere vreg1 vreg2 ;
-
-:: must-eliminate-copy ( vreg1 vreg2 -- )
- ! Eliminate a copy.
- vreg1 vreg2 eq? [
- vreg1 vreg2 vregs-interfere?
- [ vreg1 vreg2 vregs-shouldn't-interfere ]
- [ vreg1 vreg2 coalesce-vregs ]
- if
- ] unless ;
-
-M: ##tagged>integer prepare-insn
- [ dst>> ] [ src>> ] bi leaders must-eliminate-copy ;
-
-M: ##phi prepare-insn
- [ dst>> ] [ inputs>> values ] bi
- [ leaders must-eliminate-copy ] with each ;
-
-: prepare-coalescing ( cfg -- )
- init-coalescing
- [ [ prepare-insn ] each ] simple-analysis ;
-
-:: maybe-eliminate-copy ( vreg1 vreg2 -- )
- ! Eliminate a copy if possible.
- vreg1 vreg2 eq? [
- vreg1 vreg2 vregs-interfere?
- [ drop ] [ vreg1 vreg2 coalesce-vregs ] if
- ] unless ;
-
-: process-copies ( -- )
- copies get [ leaders maybe-eliminate-copy ] assoc-each ;
-
GENERIC: cleanup-insn ( insn -- )
: useful-copy? ( insn -- ? )
- [ dst>> ] [ src>> ] bi leaders eq? not ; inline
+ [ dst>> ] [ src>> ] bi leaders = not ; inline
M: ##copy cleanup-insn
dup useful-copy? [ , ] [ drop ] if ;
M: ##parallel-copy cleanup-insn
- values>>
- [ first2 leaders 2array ] map [ first2 eq? not ] filter
- [ parallel-copy-rep ] unless-empty ;
+ values>> [ leaders ] assoc-map [ first2 = ] reject
+ parallel-copy-rep % ;
M: ##tagged>integer cleanup-insn
dup useful-copy? [ , ] [ drop ] if ;
PRIVATE>
-: destruct-ssa ( cfg -- cfg' )
- needs-dominance
-
- dup construct-cssa
- dup compute-defs
- dup compute-insns
- dup compute-live-sets
- dup compute-live-ranges
- dup prepare-coalescing
- process-copies
- dup cleanup-cfg
- dup compute-live-sets ;
+: destruct-ssa ( cfg -- )
+ f leader-map set
+ {
+ needs-dominance
+ construct-cssa
+ compute-defs
+ compute-insns
+ compute-live-sets
+ compute-live-ranges
+ coalesce-cfg
+ cleanup-cfg
+ compute-live-sets
+ } apply-passes ;
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