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-rw-r--r--src/lux/compiler/case.clj3
-rw-r--r--src/lux/optimizer.clj264
2 files changed, 257 insertions, 10 deletions
diff --git a/src/lux/compiler/case.clj b/src/lux/compiler/case.clj
index 4ca543b8e..9d885942f 100644
--- a/src/lux/compiler/case.clj
+++ b/src/lux/compiler/case.clj
@@ -61,7 +61,8 @@
(doto writer
(.visitInsn Opcodes/DUP)
(.visitMethodInsn Opcodes/INVOKESTATIC "lux/LuxRT" "pm_stack_peek" "([Ljava/lang/Object;)Ljava/lang/Object;")
- (.visitVarInsn Opcodes/ASTORE _var-id))
+ (.visitVarInsn Opcodes/ASTORE _var-id)
+ (.visitMethodInsn Opcodes/INVOKESTATIC "lux/LuxRT" "pm_stack_pop" "([Ljava/lang/Object;)[Ljava/lang/Object;"))
(&o/$BoolPM _value)
(doto writer
diff --git a/src/lux/optimizer.clj b/src/lux/optimizer.clj
index 03aa5c06d..23b595886 100644
--- a/src/lux/optimizer.clj
+++ b/src/lux/optimizer.clj
@@ -111,8 +111,7 @@
(&/|list $PopPM)
(&a-case/$StoreTestAC _register)
- (&/|list ($BindPM _register)
- $PopPM)
+ (&/|list ($BindPM _register))
(&a-case/$BoolTestAC _value)
(&/|list ($BoolPM _value)
@@ -204,6 +203,57 @@
($ExecPM body-id)
(clean-unnecessary-pops (&/|reverse (transform-pm* test)))))
+(defn ^:private pattern->text [pattern]
+ (|case pattern
+ ($PopPM)
+ "$PopPM"
+
+ ($BindPM _id)
+ (str "($BindPM " _id ")")
+
+ ($BoolPM _value)
+ (str "($BoolPM " (pr-str _value) ")")
+
+ ($NatPM _value)
+ (str "($NatPM " (pr-str _value) ")")
+
+ ($IntPM _value)
+ (str "($IntPM " (pr-str _value) ")")
+
+ ($FracPM _value)
+ (str "($FracPM " (pr-str _value) ")")
+
+ ($RealPM _value)
+ (str "($RealPM " (pr-str _value) ")")
+
+ ($CharPM _value)
+ (str "($CharPM " (pr-str _value) ")")
+
+ ($TextPM _value)
+ (str "($TextPM " (pr-str _value) ")")
+
+ ($TuplePM (&/$Left _idx))
+ (str "($TuplePM L" _idx ")")
+
+ ($TuplePM (&/$Right _idx))
+ (str "($TuplePM R" _idx ")")
+
+ ($VariantPM (&/$Left _idx))
+ (str "($VariantPM L" _idx ")")
+
+ ($VariantPM (&/$Right _idx))
+ (str "($VariantPM R" _idx ")")
+
+ ($SeqPM _left _right)
+ (str "($SeqPM " (pattern->text _left) " " (pattern->text _right) ")")
+
+ ($ExecPM _idx)
+ (str "($ExecPM " _idx ")")
+
+ ;; $AltPM is not considered because it's not supposed to be
+ ;; present anywhere at this point in time.
+ ))
+
;; This function fuses together the paths of the PM traversal, adding
;; branching AltPMs where necessary, and fusing similar paths together
;; as much as possible, when early parts of them coincide.
@@ -286,17 +336,213 @@
($AltPM pre post)
))
+(defn ^:private pattern-vars [pattern]
+ (|case pattern
+ ($BindPM _id)
+ (&/|list (&/T [_id false]))
+
+ ($SeqPM _left _right)
+ (&/|++ (pattern-vars _left) (pattern-vars _right))
+
+ _
+ (&/|list)
+
+ ;; $AltPM is not considered because it's not supposed to be
+ ;; present anywhere at this point in time.
+ ))
+
+(defn ^:private find-unused-vars [var-table body]
+ (|let [[meta body-] body]
+ (|case body-
+ ($var (&/$Local _idx))
+ (&/|update _idx (fn [_] true) var-table)
+
+ ($captured _scope _c-idx [_ ($var (&/$Local _idx))])
+ (&/|update _idx (fn [_] true) var-table)
+
+ ($variant _idx _is-last? _value)
+ (find-unused-vars var-table _value)
+
+ ($tuple _elems)
+ (&/fold find-unused-vars var-table _elems)
+
+ ($ann _value-expr _type-expr)
+ (find-unused-vars var-table _value-expr)
+
+ ($apply _func _args)
+ (&/fold find-unused-vars
+ (find-unused-vars var-table _func)
+ _args)
+
+ ($proc _proc-ident _args _special-args)
+ (&/fold find-unused-vars var-table _args)
+
+ ($iter _args)
+ (&/fold find-unused-vars var-table _args)
+
+ ($let _value _register _body)
+ (-> var-table
+ (find-unused-vars _value)
+ (find-unused-vars _body))
+
+ ($record-get _value _path)
+ (find-unused-vars var-table _value)
+
+ ($if _test _then _else)
+ (-> var-table
+ (find-unused-vars _test)
+ (find-unused-vars _then)
+ (find-unused-vars _else))
+
+ ($case _value [_pm _bodies])
+ (&/fold find-unused-vars
+ (find-unused-vars var-table _value)
+ _bodies)
+
+ ($function _arity _scope _captured _body)
+ (->> _captured
+ (&/|map &/|second)
+ (&/fold find-unused-vars var-table))
+
+ _
+ var-table
+ )))
+
+(defn ^:private clean-unused-pattern-registers [var-table pattern]
+ (|case pattern
+ ($BindPM _idx)
+ (|let [_new-idx (&/|get _idx var-table)]
+ (cond (= _idx _new-idx)
+ pattern
+
+ (>= _new-idx 0)
+ ($BindPM _new-idx)
+
+ :else
+ $PopPM))
+
+ ($SeqPM _left _right)
+ ($SeqPM (clean-unused-pattern-registers var-table _left)
+ (clean-unused-pattern-registers var-table _right))
+
+ _
+ pattern
+
+ ;; $AltPM is not considered because it's not supposed to be
+ ;; present anywhere at this point in time.
+ ))
+
+;; This function assumes that the var-table has an ascending index
+;; order.
+;; For example: (2 3 4 5 6 7 8), instead of (8 7 6 5 4 3 2)
+(defn ^:private adjust-register-indexes* [offset var-table]
+ (|case var-table
+ (&/$Nil)
+ (&/|list)
+
+ (&/$Cons [_idx _used?] _tail)
+ (if _used?
+ (&/$Cons (&/T [_idx (- _idx offset)])
+ (adjust-register-indexes* offset _tail))
+ (&/$Cons (&/T [_idx -1])
+ (adjust-register-indexes* (inc offset) _tail))
+ )))
+
+(defn ^:private adjust-register-indexes [var-table]
+ (adjust-register-indexes* 0 var-table))
+
+(defn ^:private clean-unused-body-registers [var-table body]
+ (|let [[meta body-] body]
+ (|case body-
+ ($var (&/$Local _idx))
+ (|let [new-idx (or (&/|get _idx var-table)
+ _idx)]
+ (&/T [meta ($var (&/$Local new-idx))]))
+
+ ($captured _scope _c-idx [_sub-meta ($var (&/$Local _idx))])
+ (|let [new-idx (or (&/|get _idx var-table)
+ _idx)]
+ (&/T [meta ($captured _scope _c-idx (&/T [_sub-meta ($var (&/$Local new-idx))]))]))
+
+ ($variant _idx _is-last? _value)
+ (&/T [meta ($variant _idx _is-last? (clean-unused-body-registers var-table _value))])
+
+ ($tuple _elems)
+ (&/T [meta ($tuple (&/|map (partial clean-unused-body-registers var-table)
+ _elems))])
+
+ ($ann _value-expr _type-expr)
+ (&/T [meta ($ann (clean-unused-body-registers var-table _value-expr) _type-expr)])
+
+ ($apply _func _args)
+ (&/T [meta ($apply (clean-unused-body-registers var-table _func)
+ (&/|map (partial clean-unused-body-registers var-table)
+ _args))])
+
+ ($proc _proc-ident _args _special-args)
+ (&/T [meta ($proc _proc-ident
+ (&/|map (partial clean-unused-body-registers var-table)
+ _args)
+ _special-args)])
+
+ ($iter _args)
+ (&/T [meta ($iter (&/|map (partial clean-unused-body-registers var-table)
+ _args))])
+
+ ($let _value _register _body)
+ (&/T [meta ($let (clean-unused-body-registers var-table _value)
+ _register
+ (clean-unused-body-registers var-table _body))])
+
+ ($record-get _value _path)
+ (&/T [meta ($record-get (clean-unused-body-registers var-table _value)
+ _path)])
+
+ ($if _test _then _else)
+ (&/T [meta ($if (clean-unused-body-registers var-table _test)
+ (clean-unused-body-registers var-table _then)
+ (clean-unused-body-registers var-table _else))])
+
+ ($case _value [_pm _bodies])
+ (&/T [meta ($case (clean-unused-body-registers var-table _value)
+ (&/T [_pm
+ (&/|map (partial clean-unused-body-registers var-table)
+ _bodies)]))])
+
+ ($function _arity _scope _captured _body)
+ (&/T [meta ($function _arity
+ _scope
+ (&/|map (fn [capture]
+ (|let [[_name __var] capture]
+ (&/T [_name (clean-unused-body-registers var-table __var)])))
+ _captured)
+ _body)])
+
+ _
+ body
+ )))
+
+(defn ^:private optimize-register-use [pattern body]
+ (|let [p-vars (pattern-vars pattern)
+ p-vars* (find-unused-vars p-vars body)
+ adjusted-vars (adjust-register-indexes p-vars*)
+ clean-pattern (clean-unused-pattern-registers adjusted-vars pattern)
+ clean-body (clean-unused-body-registers adjusted-vars body)]
+ (&/T [clean-pattern
+ clean-body])))
+
;; This is the top-level function for optimizing PM, which transforms
;; each branch and then fuses them together.
(defn ^:private optimize-pm [branches]
(|let [;; branches (&/|reverse branches*)
- bodies (&/|map &/|second branches)
- bodies-ids (&/|range (&/|length bodies))
- pms (&/|map (fn [branch]
- (|let [[[_pattern _] _body-id] branch]
- (transform-pm _pattern _body-id)))
- (&/zip2 branches
- bodies-ids))]
+ pms+bodies (&/map2 (fn [branch _body-id]
+ (|let [[_pattern _body] branch]
+ (optimize-register-use (transform-pm _pattern _body-id)
+ _body)))
+ branches
+ (&/|range (&/|length branches)))
+ pms (&/|map &/|first pms+bodies)
+ bodies (&/|map &/|second pms+bodies)]
(|case (&/|reverse pms)
(&/$Nil)
(assert false)