From 84ea12c2960cc7460de81087a6e53bcc6d37a3d6 Mon Sep 17 00:00:00 2001
From: Eduardo Julian
Date: Sat, 28 Dec 2019 22:27:09 -0400
Subject: Optimized pattern-matching against variants.

---
 .../source/luxc/lang/translation/jvm/runtime.lux   | 100 +++++++++++----------
 1 file changed, 54 insertions(+), 46 deletions(-)

(limited to 'new-luxc')

diff --git a/new-luxc/source/luxc/lang/translation/jvm/runtime.lux b/new-luxc/source/luxc/lang/translation/jvm/runtime.lux
index 78467022e..87a5d535c 100644
--- a/new-luxc/source/luxc/lang/translation/jvm/runtime.lux
+++ b/new-luxc/source/luxc/lang/translation/jvm/runtime.lux
@@ -169,56 +169,64 @@
                          _.ARETURN))
          ($d.method #$.Public $.staticM "pm_variant" (type.method [(list //.$Variant $Tag $Flag) $Value (list)])
                     (<| _.with-label (function (_ @loop))
-                        _.with-label (function (_ @just-return))
-                        _.with-label (function (_ @then))
-                        _.with-label (function (_ @further))
-                        _.with-label (function (_ @shorten))
-                        _.with-label (function (_ @wrong))
-                        (let [variant-partI (: (-> Nat Inst)
+                        _.with-label (function (_ @perfect-match!))
+                        _.with-label (function (_ @tags-match!))
+                        _.with-label (function (_ @maybe-nested))
+                        _.with-label (function (_ @mismatch!))
+                        (let [$variant (_.ALOAD 0)
+                              $tag (_.ILOAD 1)
+                              $last? (_.ALOAD 2)
+                              
+                              variant-partI (: (-> Nat Inst)
                                                (function (_ idx)
                                                  (|>> (_.int (.int idx)) _.AALOAD)))
-                              tagI (: Inst
-                                      (|>> (variant-partI 0) (_.unwrap type.int)))
-                              flagI (variant-partI 1)
-                              datumI (variant-partI 2)
-                              shortenI (|>> (_.ALOAD 0) tagI ## Get tag
-                                            (_.ILOAD 1) _.ISUB ## Shorten tag
-                                            (_.ALOAD 0) flagI ## Get flag
-                                            (_.ALOAD 0) datumI ## Get value
-                                            variantI ## Build sum
-                                            _.ARETURN)
-                              update-tagI (|>> _.ISUB (_.ISTORE 1))
-                              update-variantI (|>> (_.ALOAD 0) datumI (_.CHECKCAST //.$Variant) (_.ASTORE 0))
-                              failureI (|>> _.NULL _.ARETURN)
-                              return-datumI (|>> (_.ALOAD 0) datumI _.ARETURN)])
-                        (|>> (_.label @loop)
-                             (_.ILOAD 1) ## tag
-                             (_.ALOAD 0) tagI ## tag, sumT
-                             _.DUP2 (_.IF_ICMPEQ @then)
-                             _.DUP2 (_.IF_ICMPGT @further)
-                             _.DUP2 (_.IF_ICMPLT @shorten)
-                             ## _.POP2
-                             failureI
-                             (_.label @then) ## tag, sumT
-                             (_.ALOAD 2) ## tag, sumT, wants-last?
-                             (_.ALOAD 0) flagI ## tag, sumT, wants-last?, is-last?
-                             (_.IF_ACMPEQ @just-return) ## tag, sumT
-                             (_.label @further) ## tag, sumT
-                             (_.ALOAD 0) flagI ## tag, sumT, last?
-                             (_.IFNULL @wrong) ## tag, sumT
-                             update-tagI
-                             update-variantI
-                             (_.GOTO @loop)
-                             (_.label @just-return) ## tag, sumT
-                             ## _.POP2
-                             return-datumI
-                             (_.label @shorten) ## tag, sumT
-                             (_.ALOAD 2) (_.IFNULL @wrong)
+                              ::tag (: Inst
+                                       (|>> (variant-partI 0) (_.unwrap type.int)))
+                              ::last? (variant-partI 1)
+                              ::value (variant-partI 2)
+
+                              super-nested-tag (|>> _.SWAP ## variant::tag, tag
+                                                    _.ISUB)
+                              super-nested (|>> super-nested-tag ## super-tag
+                                                $variant ::last? ## super-tag, super-last
+                                                $variant ::value ## super-tag, super-last, super-value
+                                                ..variantI)
+                              
+                              update-$tag _.ISUB
+                              update-$variant (|>> $variant ::value
+                                                   (_.CHECKCAST //.$Variant)
+                                                   (_.ASTORE 0))
+                              iterate! (: (-> Label Inst)
+                                          (function (_ @loop)
+                                            (|>> update-$variant
+                                                 update-$tag
+                                                 (_.GOTO @loop))))
+                              
+                              not-found _.NULL])
+                        (|>> $tag ## tag
+                             (_.label @loop)
+                             $variant ::tag ## tag, variant::tag
+                             _.DUP2 (_.IF_ICMPEQ @tags-match!) ## tag, variant::tag
+                             _.DUP2 (_.IF_ICMPGT @maybe-nested) ## tag, variant::tag
+                             $last? (_.IFNULL @mismatch!) ## tag, variant::tag
+                             super-nested ## super-variant
+                             _.ARETURN
+                             (_.label @tags-match!) ## tag, variant::tag
+                             $last? ## tag, variant::tag, last?
+                             $variant ::last? ## tag, variant::tag, last?, variant::last?
+                             (_.IF_ACMPEQ @perfect-match!) ## tag, variant::tag
+                             (_.label @maybe-nested) ## tag, variant::tag
+                             $variant ::last? ## tag, variant::tag, variant::last?
+                             (_.IFNULL @mismatch!) ## tag, variant::tag
+                             (iterate! @loop)
+                             (_.label @perfect-match!) ## tag, variant::tag
                              ## _.POP2
-                             shortenI
-                             (_.label @wrong) ## tag, sumT
+                             $variant ::value
+                             _.ARETURN
+                             (_.label @mismatch!) ## tag, variant::tag
                              ## _.POP2
-                             failureI)))
+                             not-found
+                             _.ARETURN)))
          ($d.method #$.Public $.staticM "tuple_left" (type.method [(list //.$Tuple $Index) $Value (list)])
                     (<| _.with-label (function (_ @loop))
                         _.with-label (function (_ @recursive))
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