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Work in progress on reimplementing the optimizer based on 

Oscar Waddell's dissertation (chapter 4).  The existing
optimizer in Ikarus is just a joke.
This commit is contained in:
Abdulaziz Ghuloum 2008-02-13 03:29:34 -05:00
parent 08fda34ebe
commit 66b9f6968e
5 changed files with 202 additions and 7 deletions
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3
scheme/Makefile.am
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@ -5,7 +5,8 @@ EXTRA_DIST=ikarus.boot.prebuilt ikarus.enumerations.ss \
ikarus.exceptions.ss ikarus.apply.ss ikarus.bytevectors.ss \
ikarus.cafe.ss ikarus.chars.ss ikarus.code-objects.ss \
ikarus.codecs.ss ikarus.collect.ss ikarus.command-line.ss \
ikarus.compiler.altcogen.ss ikarus.compiler.ss ikarus.control.ss \
ikarus.compiler.altcogen.ss ikarus.compiler.ss \
ikarus.compiler.source-optimizer.ss ikarus.control.ss \
ikarus.date-string.ss ikarus.fasl.ss ikarus.fasl.write.ss \
ikarus.fixnums.ss ikarus.guardians.ss ikarus.handlers.ss \
ikarus.hash-tables.ss ikarus.intel-assembler.ss \

3
scheme/Makefile.in
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@ -159,7 +159,8 @@ EXTRA_DIST = ikarus.boot.prebuilt ikarus.enumerations.ss \
ikarus.exceptions.ss ikarus.apply.ss ikarus.bytevectors.ss \
ikarus.cafe.ss ikarus.chars.ss ikarus.code-objects.ss \
ikarus.codecs.ss ikarus.collect.ss ikarus.command-line.ss \
ikarus.compiler.altcogen.ss ikarus.compiler.ss ikarus.control.ss \
ikarus.compiler.altcogen.ss ikarus.compiler.ss \
ikarus.compiler.source-optimizer.ss ikarus.control.ss \
ikarus.date-string.ss ikarus.fasl.ss ikarus.fasl.write.ss \
ikarus.fixnums.ss ikarus.guardians.ss ikarus.handlers.ss \
ikarus.hash-tables.ss ikarus.intel-assembler.ss \

187
scheme/ikarus.compiler.source-optimizer.ss Normal file
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@ -0,0 +1,187 @@
;;; Work in progress
(define (source-optimize x) x)
#!eof
;;; Oscar Waddell. "Extending the Scope of Syntactic Abstraction". PhD.
;;; Thesis. Indiana University Computer Science Department. August 1999.
;;; Available online:
;;; http://www.cs.indiana.edu/~owaddell/papers/thesis.ps.gz
(module (source-optimize)
(define who 'source-optimize)
(define-struct info (source-referenced source-assigned
residual-referenced residual-assigned))
(module (init-var! var-info)
(define (init-var! x)
(set-var-index! x (make-info #f #f #f #f)))
(define (var-info x)
(let ([v (var-index x)])
(if (info? v)
v
(error 'var-info "not initialized" x)))))
;;; purpose of prepare:
;;; 1. attach an info struct to every bound variable
;;; 2. set the plref and plset flags to indicate whether
;;; there is a reference/assignment to the variable.
;;; 3. verify well-formness of the input.
(define (prepare x)
(define (L x)
(for-each
(lambda (x)
(struct-case x
[(clambda-case info body)
(for-each init-var! (case-info-args info))
(E body)]))
(clambda-cases x)))
(define (E x)
(struct-case x
[(constant) (void)]
[(var) (set-info-source-refereced! (var-info x) #t)]
[(primref) (void)]
[(clambda) (L x)]
[(seq e0 e1) (E e0) (E e1)]
[(conditional e0 e1 e2)
(E e0) (E e1) (E e2)]
[(assign x val)
(set-info-source-assigned! (var-info x) #t)
(E val)]
[(bind lhs* rhs* body)
(for-each E rhs*)
(for-each init-var! lhs*)
(E body)]
[(fix lhs* rhs* body)
(for-each init-var! lhs*)
(for-each L rhs*)
(E body)
(for-each ;;; sanity check
(lambda (x)
(assert (not (info-source-assigned (var-info x)))))
lhs*)]
[(funcall rator rand*)
(for-each E rand*)
(E rator)]
[(forcall name rand*)
(for-each E rand*)]
[else (error who "invalid expr in prepare" x)]))
(E x))
;;; business
(define (mkseq e0 e1)
;;; returns a (seq e0 e1) with a seq-less e1 if both
;;; e0 and e1 are constructed properly.
(if (simple? e0)
e1
(let ([e0 (struct-case e0
[(seq e0a e0b) (if (simple? e0b) e0a e0)]
[else e0])])
(struct-case e1
[(seq e1a e1b) (make-seq (make-seq e0 e1a) e1b)]
[else (make-seq e0 e1)]))))
;;; simple?: check quickly whether something is effect-free
(define (simple? x)
(struct-case x
[(constant) #t]
[(var) #t]
[(primref) #t]
[(clambda) #t]
[else #f]))
;;; result returns the "last" value of an expression
(define (result x)
(struct-case x
[(seq e0 e1) e1]
[else x]))
(define (records-equal? x y)
(struct-case x
[(constant kx)
(struct-case y
[(constant ky)
(ctxt-case ctxt
[(e) #t]
[(p) (if kx ky (not ky))]
[else (eq? kx ky)])]
[else #f])]
[else #f]))
(module (E-call)
(define (residualize-operands e rand*)
(cond
[(null? rand*) e]
[(not (rand-residualize-for-effect (car rand*)))
(residualize-operands e (cdr rand*))]
[else
(let ([e1 (process-rands-for-effect rand*)])
(mkseq e1 (residualize-operands e (cdr rand*))))]))
(define (value-visit-operand! rand)
(or (rand-value rand)
(let ([e (E (rand-expr rand) (rand-env rand) 'v)])
(set-rand-value! rand e)
e)))
(define (E-call rator rand* env ctxt)
(let ([ctxt (make-app-ctxt rand* ctxt)])
(let ([rator (E rator env ctxt)])
(if (app-inlined ctxt)
(residualize-operand rator rand*)
(make-funcall rator
(map value-visit-operand! rand*)))))))
(define (E x env ctxt)
(struct-case x
[(constant) x]
[(var) (E-var x env ctxt)]
[(seq e0 e1)
(mkseq (E e0 env 'e) (E e1 env ctxt))]
[(conditional e0 e1 e2)
(let ([e0 (E e0 env 'p)])
(struct-case (result e0)
[(constant k)
(mkseq e0 (E (if k e1 e2) env ctxt))]
[else
(let ([ctxt (ctxt-case ctxt [(app) 'v] [else ctxt])])
(let ([e1 (E e1 env ctxt)]
[e2 (E e2 env ctxt)])
(if (records-equal? e1 e2 ctxt)
(mkseq e0 e1)
(make-conditional e0 e1 e2))))]))]
[(assign x v)
(mkseq
(let ([xi (var-info x)])
(cond
[(not (info-source-referenced xi))
;;; dead on arrival
(E v env 'e)]
[else
(set-info-residual-assigned! i #t)
(make-assign x (E v env 'v))]))
(make-constant (void)))]
[(funcall rator rand*)
(E-call rator (map (mkoperand env) rand*) env ctxt)]
[(primref name)
(ctxt-case ctxt
[(app) (E-fold-prim name env ctxt)]
[(value) x]
[else (make-constant (void))])]
[(clambda g cases cp free name)
(ctxt-case ctxt
[(app) (E-inline x env ctxt)]
[(p e) (make-constant (void))]
[else
(make-clambda g
(map
(lambda (x)
(struct-case x
[(clambda-case info body)
(struct-case info
[(case-info label args proper)
(with-extended-env ((env args) (env args #f))
(make-clambda-case
(make-info label args proper)
(E body env 'v)))])]))
cases)
cp free name)])]
[else (error who "invalid expression" x)]))
(define (source-optimize expr)
(prepare expr)
(E expr 'v)))

10
scheme/ikarus.compiler.ss
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@ -837,7 +837,7 @@
[else
(values '()
(mklet (list (binding-lhs b))
(list (make-primcall 'void '()))
(list (make-funcall (make-primref 'void) '()))
(mkset!s scc
(mkfix fix* body))))]))]
[else
@ -851,7 +851,8 @@
(if ordered? (sort-bindings complex*) complex*)])
(values '()
(mklet (map binding-lhs complex*)
(map (lambda (x) (make-primcall 'void '()))
(map (lambda (x)
(make-funcall (make-primref 'void) '()))
complex*)
(mkfix (append lambda* fix*)
(mkset!s complex* body)))))]))]))
@ -984,6 +985,10 @@
;(pretty-print (unparse x))
x))
(include "ikarus.compiler.source-optimizer.ss")
(define (uncover-assigned/referenced x)
(define who 'uncover-assigned/referenced)
(define (Expr* x*)
@ -3048,6 +3053,7 @@
[p (if (scc-letrec)
(optimize-letrec/scc p)
(optimize-letrec p))]
[p (source-optimize p)]
[p (uncover-assigned/referenced p)]
[p (copy-propagate p)]
[p (rewrite-assignments p)]

2
scheme/last-revision
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@ -1 +1 @@
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