racket/collects/macro-debugger/analysis/private/nom-use-alg.rkt
2013-03-30 10:00:44 -04:00

192 lines
7.8 KiB
Racket

#lang racket/base
(require racket/match
"moduledb.rkt"
"util.rkt")
(provide nom-use-alg)
;; nom-use-alg : Refs compiled -> (listof recommendation)
(define (nom-use-alg refs0 compiled)
(let ([refs (append (provides->refs compiled) refs0)])
(let-values ([(NOM-USES DEF-USES) (calculate-used-approximations refs)])
(report NOM-USES DEF-USES (get-requires compiled)))))
;; ========
;; sMPI = S-expr form of mpi (see mpi->key)
;; Using MPIs doesn't work. I conjecture that the final module shift means that
;; all during-expansion MPIs are different from all compiled-expr MPIs.
;; A UsedTable = hash[(list int sMPI) => Refs]
;; calculate-used-approximations : Refs -> (values UsedTable UsedTable)
(define (calculate-used-approximations refs)
(let ([NOM-USES (make-hash)]
[DEF-USES (make-hash)])
(for ([ref (in-list refs)])
(when (relevant? ref)
(match (ref-binding ref)
[(list def-mod def-sym nom-mod nom-sym
def-phase nom-imp-phase nom-exp-phase)
(define use-phase (ref-phase ref))
(when def-mod
;; use-phase = def-phase + required-phase
;; thus required-phase = use-phase - def-phase
(let* ([required-phase (- use-phase def-phase)]
[key (list required-phase (mpi->key def-mod))])
(hash-set! DEF-USES key
(cons ref (hash-ref DEF-USES key null)))))
;; We just care about nom-imp-phase, since importing into *here*
(let* ([key (list nom-imp-phase (mpi->key nom-mod))])
(hash-set! NOM-USES key
(cons ref (hash-ref NOM-USES key null))))]
[_ (void)])))
(values NOM-USES DEF-USES)))
;; relevant? : Ref -> boolean
;; Only want identifiers actually originating from module being analyzed,
;; not identifiers from other modules inserted by macro expansion.
;; - Actually, want identifiers with lexical context of module, which includes
;; some identifiers not originating from module (eg, inserted by unit-from-context).
;; - Also, if ref represents a re-export, no identifier but still relevant.
;; So, use syntax-source-module conservatively: only to disqualify refs.
(define (relevant? ref)
(let* ([phase (ref-phase ref)]
[id (ref-id ref)]
[binding (ref-binding ref)]
[srcmod (and id (syntax-source-module id))])
(cond [(and srcmod (not (here-mpi? srcmod))) #f]
[else #t])))
;; ========
;; get-requires : compiled-module-expr -> (listof (list int MPI))
(define (get-requires compiled)
(let ([phase+mods-list (module-compiled-imports compiled)])
(for*/list ([phase+mods (in-list phase+mods-list)]
#:when (car phase+mods) ;; Skip for-label requires
[mod (cdr phase+mods)])
(list (car phase+mods) mod))))
;; provides->refs : compiled-module-expr -> Refs
(define (provides->refs compiled)
(let-values ([(vprov sprov) (module-compiled-exports compiled)])
(for*/list ([phase+exps (in-list (append vprov sprov))]
#:when (car phase+exps) ;; Skip for-label provides
[name+srcs (in-list (cdr phase+exps))]
[src (in-list (cadr name+srcs))])
(let ([phase (car phase+exps)]
[name (car name+srcs)])
(define (->ref nom-mod exp-sym phase-shift sym orig-phase)
;; We don't have the DEF information, so put #f
(let ([b (list #f #f nom-mod sym #f phase-shift orig-phase)])
(ref phase #f 'provide b)))
(match src
[(? module-path-index?)
(->ref src name 0 name phase)]
[(list imp-mod imp-phase-shift imp-name imp-orig-phase)
(->ref imp-mod name imp-phase-shift imp-name imp-orig-phase)])))))
;; ========
;; A RefineTable is hash[(cons mpi phase) => (or RefineTable Imps)]
;; preserve nesting because inner MPIs need to be resolved wrt outer MPIs
;; try-bypass : mpi phase Refs -> RefineTable or #f
(define (try-bypass mod reqphase refs)
;; refs are all nominally from mod
(let* ([imps (map ref->imp refs)])
(refine-imps/one-require mod reqphase imps)))
;; refine-imps/one-require : mpi phase Imps -> RefineTable or #f
;; where all imps come from mod at phase
;; the result table contains new (refined) imps
(define (refine-imps/one-require mod reqphase imps)
(let ([use-table (make-hash)] ;; RefineTable
[bytable (mod->bypass-table mod)])
(and (for/and ([i (in-list imps)])
(match i
[(imp _m _rp sym exp-phase r)
(let* ([bykey (cons sym exp-phase)]
[src (hash-ref bytable bykey #f)])
(match src
[(renm srcmod phase-shift srcsym srcphase)
(let ([use-key (cons srcmod (+ reqphase phase-shift))]
[imp* (imp srcmod (+ reqphase phase-shift) srcsym srcphase r)])
(hash-set! use-table use-key (cons imp* (hash-ref use-table use-key null))))
#t]
[else #f]))]))
(refine-imps* use-table))))
(define (refine-imps* partitions)
(for/hash ([(mod+reqphase imps) (in-hash partitions)])
(values mod+reqphase
(let ([mod (car mod+reqphase)]
[reqphase (cdr mod+reqphase)])
(or (and (allow-bypass? mod)
(refine-imps/one-require mod reqphase imps))
imps)))))
;; ========
;; A BypassTable is hash[(cons sym phase) => Renm
;; Contains only approved modules (no private, etc).
;; A Renm is (renm srcmod reqphase srcsym)
(struct renm (srcmod phase-shift srcsym srcphase))
;; mod->bypass-table : mpi -> BypassTable
;; FIXME: cache tables
(define (mod->bypass-table mod)
(define table (make-hash))
(let ([prov (get-module-all-exports mod)])
(for* ([phase+exps (in-list prov)]
#:when (car phase+exps) ;; Skip for-label provides
[name+srcs (in-list (cdr phase+exps))]
[src (in-list (cadr name+srcs))])
(let ([phase (car phase+exps)]
[name (car name+srcs)])
(define (add-source! src-mod phase-offset src-sym)
(when (bypass-ok-mpi? src-mod)
(let ([key (cons name phase)]
;; src-phase + phase-shift = phase
[src-phase (- phase phase-offset)])
(hash-ref! table key (renm src-mod phase-offset src-sym src-phase)))))
(match src
[(? module-path-index?)
(add-source! src 0 name)]
[(list imp-mod imp-phase-shift imp-name imp-orig-phase)
(add-source! imp-mod imp-phase-shift imp-name)]))))
table)
;; ========
;; report : UseTable UseTable (listof (list int mpi)) -> (listof recommendation)
(define (report NOM-USES DEF-USES phase+mod-list)
(for/list ([phase+mod (in-list phase+mod-list)])
(let* ([phase (car phase+mod)]
[mod (cadr phase+mod)]
[key (list phase (mpi->key mod))]
[nom-refs (hash-ref NOM-USES key null)]
[def-refs (hash-ref DEF-USES key null)])
(cond [(and (pair? nom-refs) (pair? def-refs))
;; We use refs defined in the module (and we got them from the module)
(list 'keep mod phase (map ref->imp nom-refs))]
[(pair? nom-refs)
;; We use refs gotten from the module (but defined elsewhere)
(let ([bypass
(and (allow-bypass? mod)
(try-bypass mod phase nom-refs))])
(if bypass
(list 'bypass mod phase bypass)
(list 'keep mod phase (map ref->imp nom-refs))))]
[else
;; We don't have any refs gotten from the module
;; (although we may---possibly---have refs defined in it, but gotten elsewhere)
(if (allow-drop? mod)
(list 'drop mod phase)
(list 'keep mod phase null))]))))