609 lines
27 KiB
Racket
609 lines
27 KiB
Racket
#lang typed/racket/base
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(require "expression-structs.rkt"
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"lexical-structs.rkt"
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"il-structs.rkt"
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"lexical-env.rkt"
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"helpers.rkt"
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"find-toplevel-variables.rkt"
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"sets.rkt"
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racket/list)
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(provide (rename-out [-compile compile])
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compile-procedure-call
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append-instruction-sequences
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call/cc-label
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make-call/cc-code)
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;(provide compile-top)
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(: -compile (ExpressionCore Target Linkage -> (Listof Statement)))
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(define (-compile exp target linkage)
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(statements
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(let ([end (make-label 'end)])
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(append-instruction-sequences
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(compile (make-Top (make-Prefix (find-toplevel-variables exp))
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exp)
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(list)
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target
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linkage)
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(make-instruction-sequence `(,(make-GotoStatement (make-Label end))))
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(make-call/cc-code)
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end))))
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(: compile (ExpressionCore CompileTimeEnvironment Target Linkage -> InstructionSequence))
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;; Compiles an expression into an instruction sequence.
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(define (compile exp cenv target linkage)
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(cond
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[(Top? exp)
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(compile-top exp cenv target linkage)]
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[(Constant? exp)
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(compile-constant exp cenv target linkage)]
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[(Var? exp)
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(compile-variable exp cenv target linkage)]
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[(Def? exp)
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(compile-definition exp cenv target linkage)]
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[(Branch? exp)
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(compile-branch exp cenv target linkage)]
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[(Lam? exp)
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(compile-lambda exp cenv target linkage)]
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[(Seq? exp)
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(compile-sequence (Seq-actions exp)
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cenv
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target
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linkage)]
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[(App? exp)
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(compile-application exp cenv target linkage)]
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[(Let1? exp)
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(compile-let1 exp cenv target linkage)]
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#;[(Letrec? exp)
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(compile-letrec exp cenv target linkage)]))
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(: compile-top (Top CompileTimeEnvironment Target Linkage -> InstructionSequence))
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(define (compile-top top cenv target linkage)
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(let*: ([cenv : CompileTimeEnvironment (extend-lexical-environment cenv (Top-prefix top))]
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[names : (Listof Symbol) (Prefix-names (Top-prefix top))])
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(append-instruction-sequences
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(make-instruction-sequence
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`(,(make-PerformStatement (make-ExtendEnvironment/Prefix! names))))
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(compile (Top-code top) cenv target linkage))))
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;; Add linkage for expressions.
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(: end-with-linkage (Linkage CompileTimeEnvironment InstructionSequence ->
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InstructionSequence))
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(define (end-with-linkage linkage cenv instruction-sequence)
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(append-instruction-sequences instruction-sequence
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(compile-linkage cenv linkage)))
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(: end-with-compiled-application-linkage (Linkage CompileTimeEnvironment InstructionSequence ->
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InstructionSequence))
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;; Add linkage for applications; we need to specialize this to preserve tail calls.
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(define (end-with-compiled-application-linkage linkage cenv instruction-sequence)
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(append-instruction-sequences instruction-sequence
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(compile-application-linkage cenv linkage)))
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(: compile-linkage (CompileTimeEnvironment Linkage -> InstructionSequence))
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(define (compile-linkage cenv linkage)
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(cond
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[(eq? linkage 'return)
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(make-instruction-sequence `(,(make-AssignPrimOpStatement 'proc
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(make-GetControlStackLabel))
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,(make-PopEnvironment
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(lexical-environment-pop-depth cenv linkage)
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0)
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,(make-PopControlFrame)
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,(make-GotoStatement (make-Reg 'proc))))]
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[(eq? linkage 'next)
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empty-instruction-sequence]
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[(symbol? linkage)
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(make-instruction-sequence `(,(make-GotoStatement (make-Label linkage))))]))
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(: compile-application-linkage (CompileTimeEnvironment Linkage -> InstructionSequence))
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;; Like compile-linkage, but the special case for 'return linkage already assumes
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;; the stack has been appropriately popped.
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(define (compile-application-linkage cenv linkage)
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(cond
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[(eq? linkage 'return)
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(make-instruction-sequence `(,(make-AssignPrimOpStatement 'proc
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(make-GetControlStackLabel))
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,(make-PopControlFrame)
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,(make-GotoStatement (make-Reg 'proc))))]
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[(eq? linkage 'next)
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(make-instruction-sequence `(,(make-PopEnvironment (lexical-environment-pop-depth cenv linkage)
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0)))]
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[(symbol? linkage)
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(make-instruction-sequence `(,(make-PopEnvironment (lexical-environment-pop-depth cenv linkage)
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0)
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,(make-GotoStatement (make-Label linkage))))]))
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(: lexical-environment-pop-depth (CompileTimeEnvironment Linkage -> Natural))
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;; Computes how much of the environment we need to pop.
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(define (lexical-environment-pop-depth cenv linkage)
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(length cenv))
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(: compile-constant (Constant CompileTimeEnvironment Target Linkage -> InstructionSequence))
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(define (compile-constant exp cenv target linkage)
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(end-with-linkage linkage
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cenv
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(make-instruction-sequence
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`(,(make-AssignImmediateStatement target (make-Const (Constant-v exp)))))))
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(: compile-variable (Var CompileTimeEnvironment Target Linkage -> InstructionSequence))
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(define (compile-variable exp cenv target linkage)
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(let ([lexical-pos (find-variable (Var-id exp) cenv)])
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(cond
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[(LocalAddress? lexical-pos)
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(end-with-linkage linkage
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cenv
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(make-instruction-sequence
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`(,(make-AssignImmediateStatement
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target
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(make-EnvLexicalReference (LocalAddress-depth lexical-pos))))))]
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[(PrefixAddress? lexical-pos)
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(end-with-linkage linkage
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cenv
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(make-instruction-sequence
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`(,(make-PerformStatement (make-CheckToplevelBound!
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(PrefixAddress-depth lexical-pos)
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(PrefixAddress-pos lexical-pos)
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(PrefixAddress-name lexical-pos)))
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,(make-AssignImmediateStatement
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target
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(make-EnvPrefixReference
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(PrefixAddress-depth lexical-pos)
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(PrefixAddress-pos lexical-pos))))))])))
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(: compile-definition (Def CompileTimeEnvironment Target Linkage -> InstructionSequence))
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(define (compile-definition exp cenv target linkage)
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(let* ([var (Def-variable exp)]
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[lexical-pos (find-variable var cenv)])
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(cond
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[(LocalAddress? lexical-pos)
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(error 'compile-definition "Defintion not at toplevel")]
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[(PrefixAddress? lexical-pos)
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(let ([get-value-code
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(compile (Def-value exp) cenv (make-EnvPrefixReference
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(PrefixAddress-depth lexical-pos)
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(PrefixAddress-pos lexical-pos))
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'next)])
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(end-with-linkage
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linkage
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cenv
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(append-instruction-sequences
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get-value-code
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(make-instruction-sequence `(,(make-AssignImmediateStatement target (make-Const 'ok)))))))])))
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(: compile-branch (Branch CompileTimeEnvironment Target Linkage -> InstructionSequence))
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(define (compile-branch exp cenv target linkage)
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(let ([t-branch (make-label 'trueBranch)]
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[f-branch (make-label 'falseBranch)]
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[after-if (make-label 'afterIf)])
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(let ([consequent-linkage
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(if (eq? linkage 'next)
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after-if
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linkage)])
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(let ([p-code (compile (Branch-predicate exp) cenv 'val 'next)]
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[c-code (compile (Branch-consequent exp) cenv target consequent-linkage)]
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[a-code (compile (Branch-alternative exp) cenv target linkage)])
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(append-instruction-sequences p-code
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(append-instruction-sequences
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(make-instruction-sequence
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`(,(make-TestAndBranchStatement 'false?
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'val
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f-branch)
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))
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(append-instruction-sequences
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(append-instruction-sequences t-branch c-code)
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(append-instruction-sequences f-branch a-code))
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after-if))))))
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(: compile-sequence ((Listof Expression) CompileTimeEnvironment Target Linkage -> InstructionSequence))
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(define (compile-sequence seq cenv target linkage)
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;; All but the last will use 'next linkage.
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(if (last-exp? seq)
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(compile (first-exp seq) cenv target linkage)
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(append-instruction-sequences (compile (first-exp seq) cenv target 'next)
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(compile-sequence (rest-exps seq) cenv target linkage))))
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(: compile-lambda (Lam CompileTimeEnvironment Target Linkage -> InstructionSequence))
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;; Write out code for lambda expressions.
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;; The lambda will close over the free variables.
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(define (compile-lambda exp cenv target linkage)
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(let*: ([proc-entry : Symbol (make-label 'entry)]
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[after-lambda : Symbol (make-label 'afterLambda)]
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[lambda-linkage : Linkage
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(if (eq? linkage 'next)
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after-lambda
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linkage)]
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[free-vars : (Listof Symbol) (find-toplevel-variables exp)]
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[lexical-addresses : (Listof LexicalAddress)
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(map (lambda: ([var : Symbol])
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(find-variable var cenv))
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free-vars)]
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[lexical-references : (Listof EnvReference)
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(collect-lexical-references lexical-addresses)])
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(append-instruction-sequences
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(end-with-linkage
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lambda-linkage
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cenv
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(make-instruction-sequence
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`(,(make-AssignPrimOpStatement target
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(make-MakeCompiledProcedure proc-entry
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(length (Lam-parameters exp))
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lexical-references)))))
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(compile-lambda-body exp cenv
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lexical-references
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proc-entry)
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after-lambda)))
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(: compile-lambda-body (Lam CompileTimeEnvironment
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(Listof EnvReference)
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Linkage
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->
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InstructionSequence))
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;; Compiles the body of the lambda in the appropriate environment.
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(define (compile-lambda-body exp cenv lexical-references proc-entry)
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(let*: ([formals : (Listof Symbol) (Lam-parameters exp)]
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[extended-cenv : CompileTimeEnvironment
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(extend-lexical-environment/names
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'()
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formals)]
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[extended-cenv : CompileTimeEnvironment
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(lexical-references->compile-time-environment
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lexical-references cenv extended-cenv)])
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(append-instruction-sequences
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(make-instruction-sequence
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`(,proc-entry
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,(make-PerformStatement (make-InstallClosureValues!))))
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(compile (Lam-body exp) extended-cenv 'val 'return))))
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#;(: compile-letrec (Letrec CompileTimeEnvironment Target Linkage -> InstructionSequence))
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#;(define (compile-letrec exp cenv target linkage)
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(let* ([after-let (make-label 'afterLet)]
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[let-linkage (if (eq? linkage 'next)
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after-let
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linkage)]
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[extended-cenv : CompileTimeEnvironment
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(extend-lexical-environment/names
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'()
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(reverse (Letrec-names exp)))]
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[lam-codes : (Listof InstructionSequence)
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(let: ([n : Natural (length (Letrec-procs exp))])
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(map (lambda: ([lam : Lam]
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[target : Target])
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(compile-lambda lam extended-cenv target 'next))
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(Letrec-procs exp)
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(build-list (length (Letrec-procs exp))
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(lambda: ([i : Natural])
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(make-EnvLexicalReference (- n 1 i))))))]
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[body-code : InstructionSequence
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(compile (Letrec-body exp) extended-cenv target let-linkage)]
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(append-instruction-sequences
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(end-with-linkage let-linkage cenv
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(make-instruction-sequence `(;; create space for the lambdas
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,(make-PushEnvironment n)
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;; install each one of them in place
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(apply append-instruction-sequences lam-codes)
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;; mutate each of the lambda's shells so they're correct
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;; evaluate the body
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body-code
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;; pop the temporary space
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)))
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after-let))))
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;; FIXME: I need to implement important special cases.
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;; 1. We may be able to open-code if the operator is primitive
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;; 2. We may have a static location to jump to if the operator is lexically scoped.
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(: compile-application (App CompileTimeEnvironment Target Linkage -> InstructionSequence))
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(define (compile-application exp cenv target linkage)
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(let* ([extended-cenv (extend-lexical-environment/placeholders cenv (length (App-operands exp)))]
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[proc-code (compile (App-operator exp)
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extended-cenv
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(if (empty? (App-operands exp))
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'proc
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(make-EnvLexicalReference
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(ensure-natural (sub1 (length (App-operands exp))))))
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'next)]
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[operand-codes (map (lambda: ([operand : Expression]
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[target : Target])
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(compile operand extended-cenv target 'next))
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(App-operands exp)
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(build-list (length (App-operands exp))
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(lambda: ([i : Natural])
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(if (< i (sub1 (length (App-operands exp))))
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(make-EnvLexicalReference i)
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'val))))])
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(append-instruction-sequences
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(make-instruction-sequence `(,(make-PushEnvironment (length (App-operands exp)))))
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proc-code
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(juggle-operands operand-codes)
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(compile-procedure-call cenv extended-cenv
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(length (App-operands exp))
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target linkage))))
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(: juggle-operands ((Listof InstructionSequence) -> InstructionSequence))
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;; Installs the operators. At the end of this,
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;; the procedure lives in 'proc, and the operands on the environment stack.
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(define (juggle-operands operand-codes)
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(let: loop : InstructionSequence ([ops : (Listof InstructionSequence) operand-codes])
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(cond
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;; If there are no operands, no need to juggle.
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[(null? ops)
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(make-instruction-sequence empty)]
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[(null? (rest ops))
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(let: ([n : Natural (ensure-natural (sub1 (length operand-codes)))])
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;; The last operand needs to be handled specially: it currently lives in
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;; val. We move the procedure at env[n] over to proc, and move the
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;; last operand at 'val into env[n].
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(append-instruction-sequences
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(car ops)
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(make-instruction-sequence
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`(,(make-AssignImmediateStatement 'proc
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(make-EnvLexicalReference n))
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,(make-AssignImmediateStatement (make-EnvLexicalReference n)
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(make-Reg 'val))))))]
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[else
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;; Otherwise, add instructions to juggle the operator and operands in the stack.
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(append-instruction-sequences (car ops)
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(loop (rest ops)))])))
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(: compile-procedure-call (CompileTimeEnvironment CompileTimeEnvironment
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Natural Target Linkage
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->
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InstructionSequence))
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;; Assumes the procedure value has been loaded into the proc register.
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;; n is the number of arguments passed in.
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;; cenv is the compile-time enviroment before arguments have been shifted in.
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;; extended-cenv is the compile-time environment after arguments have been shifted in.
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(define (compile-procedure-call cenv extended-cenv n target linkage)
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(let ([primitive-branch (make-label 'primitiveBranch)]
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[compiled-branch (make-label 'compiledBranch)]
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[after-call (make-label 'afterCall)])
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(let ([compiled-linkage (if (eq? linkage 'next) after-call linkage)])
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(append-instruction-sequences
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(make-instruction-sequence
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`(,(make-TestAndBranchStatement 'primitive-procedure?
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'proc
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primitive-branch)))
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compiled-branch
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(make-instruction-sequence
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`(,(make-PerformStatement (make-CheckClosureArity! n))))
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(end-with-compiled-application-linkage
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compiled-linkage
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extended-cenv
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(compile-proc-appl extended-cenv n target compiled-linkage))
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primitive-branch
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(end-with-linkage
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linkage
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cenv
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(make-instruction-sequence
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`(,(make-AssignPrimOpStatement
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;; Optimization: we put the result directly in the registers, or in
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;; the appropriate spot on the stack. This takes into account the popenviroment
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;; that happens right afterwards.
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(adjust-target-depth target n)
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(make-ApplyPrimitiveProcedure n after-call))
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,(make-PopEnvironment n 0))))
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after-call))))
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(: compile-proc-appl (CompileTimeEnvironment Natural Target Linkage -> InstructionSequence))
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;; Three fundamental cases for general compiled-procedure application.
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;; 1. Non-tail calls that write to val
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;; 2. Calls in argument position that write to the environment
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;; 3. Tail calls.
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;; The Other cases should be excluded.
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(define (compile-proc-appl cenv n target linkage)
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(cond [(and (eq? target 'val)
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(not (eq? linkage 'return)))
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;; This case happens for a function call that isn't in
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;; tail position.
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(make-instruction-sequence
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`(,(make-PushControlFrame linkage)
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,(make-AssignPrimOpStatement 'val (make-GetCompiledProcedureEntry))
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,(make-GotoStatement (make-Reg 'val))))]
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[(and (not (eq? target 'val))
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(not (eq? linkage 'return)))
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;; This case happens for evaluating arguments, since the
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;; arguments are being installed into the scratch space.
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(let ([proc-return (make-label 'procReturn)])
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(make-instruction-sequence
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`(,(make-PushControlFrame proc-return)
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,(make-AssignPrimOpStatement 'val (make-GetCompiledProcedureEntry))
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,(make-GotoStatement (make-Reg 'val))
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,proc-return
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,(make-AssignImmediateStatement target (make-Reg 'val))
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,(make-GotoStatement (make-Label linkage)))))]
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[(and (eq? target 'val)
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(eq? linkage 'return))
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;; This case happens when we're in tail position.
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;; We clean up the stack right before the jump, and do not add
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;; to the control stack.
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(make-instruction-sequence
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`(,(make-AssignPrimOpStatement 'val
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(make-GetCompiledProcedureEntry))
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,(make-PopEnvironment (ensure-natural (- (lexical-environment-pop-depth cenv linkage)
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n))
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n)
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,(make-GotoStatement (make-Reg 'val))))]
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[(and (not (eq? target 'val))
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(eq? linkage 'return))
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;; This case should be impossible: return linkage should only
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;; occur when we're in tail position, and we're in tail position
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;; only when the target is the val register.
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(error 'compile "return linkage, target not val: ~s" target)]))
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(: compile-let1 (Let1 CompileTimeEnvironment Target Linkage -> InstructionSequence))
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(define (compile-let1 exp cenv target linkage)
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(let*: ([rhs-code : InstructionSequence
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(compile (Let1-rhs exp)
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(extend-lexical-environment/placeholders cenv 1)
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(make-EnvLexicalReference 0)
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'next)]
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[after-let1 : Symbol (make-label 'afterLetOne)]
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[after-body-code : Symbol (make-label 'afterLetBody)]
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[extended-cenv : CompileTimeEnvironment
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(extend-lexical-environment/names cenv (list (Let1-name exp)))]
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[let-linkage : Linkage
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(cond
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[(eq? linkage 'next)
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'next]
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[(eq? linkage 'return)
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'return]
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[(symbol? linkage)
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after-body-code])]
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[body-target : Target (adjust-target-depth target 1)]
|
|
[body-code : InstructionSequence
|
|
(compile (Let1-body exp) extended-cenv body-target let-linkage)])
|
|
(end-with-linkage
|
|
linkage
|
|
extended-cenv
|
|
(append-instruction-sequences (make-instruction-sequence `(,(make-PushEnvironment 1)))
|
|
rhs-code
|
|
body-code
|
|
after-body-code
|
|
(make-instruction-sequence `(,(make-PopEnvironment 1 0)))
|
|
after-let1))))
|
|
|
|
(: adjust-target-depth (Target Natural -> Target))
|
|
(define (adjust-target-depth target n)
|
|
(cond
|
|
[(eq? target 'val)
|
|
target]
|
|
[(eq? target 'proc)
|
|
target]
|
|
[(EnvLexicalReference? target)
|
|
(make-EnvLexicalReference (+ n (EnvLexicalReference-depth target)))]
|
|
[(EnvPrefixReference? target)
|
|
(make-EnvPrefixReference (+ n (EnvPrefixReference-depth target))
|
|
(EnvPrefixReference-pos target))]))
|
|
|
|
|
|
|
|
(: append-instruction-sequences (InstructionSequence * -> InstructionSequence))
|
|
(define (append-instruction-sequences . seqs)
|
|
(append-seq-list seqs))
|
|
|
|
(: append-2-sequences (InstructionSequence InstructionSequence -> InstructionSequence))
|
|
(define (append-2-sequences seq1 seq2)
|
|
(make-instruction-sequence
|
|
(append (statements seq1) (statements seq2))))
|
|
|
|
(: append-seq-list ((Listof InstructionSequence) -> InstructionSequence))
|
|
(define (append-seq-list seqs)
|
|
(if (null? seqs)
|
|
empty-instruction-sequence
|
|
(append-2-sequences (car seqs)
|
|
(append-seq-list (cdr seqs)))))
|
|
|
|
(: ensure-natural (Integer -> Natural))
|
|
(define (ensure-natural n)
|
|
(if (>= n 0)
|
|
n
|
|
(error 'ensure-natural "Not a natural: ~s\n" n)))
|
|
|
|
|
|
|
|
|
|
|
|
|
|
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
|
|
|
|
|
|
;; The primitive code necessary to do call/cc
|
|
|
|
(: call/cc-label Symbol)
|
|
(define call/cc-label 'callCCEntry)
|
|
(define call/cc-closure-entry 'callCCClosureEntry)
|
|
|
|
|
|
;; (call/cc f)
|
|
;; Tail-calls f, providing it a special object that knows how to do the low-level
|
|
;; manipulation of the environment and control stack.
|
|
(define (make-call/cc-code)
|
|
(append-instruction-sequences
|
|
(make-instruction-sequence
|
|
`(,call/cc-label
|
|
;; Precondition: the environment holds the f function that we want to jump into.
|
|
|
|
;; First, move f to the proc register
|
|
,(make-AssignImmediateStatement 'proc (make-EnvLexicalReference 0))
|
|
|
|
;; Next, capture the envrionment and the current continuation closure,.
|
|
,(make-PushEnvironment 2)
|
|
,(make-AssignPrimOpStatement (make-EnvLexicalReference 0)
|
|
(make-CaptureControl 0))
|
|
,(make-AssignPrimOpStatement (make-EnvLexicalReference 1)
|
|
;; When capturing, skip over f and the two slots we just added.
|
|
(make-CaptureEnvironment 3))
|
|
,(make-AssignPrimOpStatement (adjust-target-depth (make-EnvLexicalReference 0) 2)
|
|
(make-MakeCompiledProcedure call/cc-closure-entry
|
|
1 ;; the continuation consumes a single value
|
|
(list (make-EnvLexicalReference 0)
|
|
(make-EnvLexicalReference 1))))
|
|
,(make-PopEnvironment 2 0)))
|
|
|
|
;; Finally, do a tail call into f.
|
|
(compile-procedure-call '()
|
|
(extend-lexical-environment/placeholders '() 1)
|
|
1
|
|
'val
|
|
'return)
|
|
|
|
;; The code for the continuation coe follows. It's supposed to
|
|
;; abandon the current continuation, initialize the control and environment, and then jump.
|
|
(make-instruction-sequence `(,call/cc-closure-entry
|
|
,(make-AssignImmediateStatement 'val (make-EnvLexicalReference 0))
|
|
,(make-PerformStatement (make-InstallClosureValues!))
|
|
,(make-PerformStatement (make-RestoreControl!))
|
|
,(make-PerformStatement (make-RestoreEnvironment!))
|
|
,(make-AssignPrimOpStatement 'proc (make-GetControlStackLabel))
|
|
,(make-PopControlFrame)
|
|
,(make-GotoStatement (make-Reg 'proc))))))
|