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guile/module/system/il/compile.scm
Andy Wingo 7e4760e413 fix bug in compilation of and' and or'; more robust underflow detection.
* module/system/il/compile.scm (codegen): Rewrite handling of `and' and
  `or' ghil compilation, because it was broken if drop was #t. Tricky
  bug, this one! Took me days to track down!

* module/system/repl/repl.scm: Export call-with-backtrace, which probably
  should go in some other file.

* src/vm.c (scm_vm_save_stack): Handle the fp==0 case for errors before
  we have a frame.

* src/vm_engine.h (NEW_FRAME, FREE_FRAME): Stricter underflow checking,
  raising the stack base to the return address, in an attempt to prevent
  inadvertant stack smashing (the symptom of the and/or miscompilation
  bug).
  (CHECK_IP): A check that the current IP is within the bounds of the
  current program. Not normally compiled in. Perhaps it should be?

* src/vm_system.c (halt): Set vp->ip to NULL. Paranoia, I know.
  (return): Call CHECK_IP(), if such a thing is compiled in.

* testsuite/Makefile.am (vm_test_files):
* testsuite/t-catch.scm:
* testsuite/t-map.scm:
* testsuite/t-or.scm: New tests.
2008-08-11 18:35:58 +02:00

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;;; GHIL -> GLIL compiler
;; Copyright (C) 2001 Free Software Foundation, Inc.
;; This program is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation; either version 2, or (at your option)
;; any later version.
;;
;; This program is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;; GNU General Public License for more details.
;;
;; You should have received a copy of the GNU General Public License
;; along with this program; see the file COPYING. If not, write to
;; the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
;; Boston, MA 02111-1307, USA.
;;; Code:
(define-module (system il compile)
:use-syntax (system base syntax)
:use-module (system il glil)
:use-module (system il ghil)
:use-module (ice-9 common-list)
:export (compile))
(define (compile x e . opts)
(if (memq :O opts) (set! x (optimize x)))
(codegen x))
;;;
;;; Stage 2: Optimization
;;;
(define (optimize x)
(record-case x
((<ghil-set> env loc var val)
(make-ghil-set env var (optimize val)))
((<ghil-if> env loc test then else)
(make-ghil-if env loc (optimize test) (optimize then) (optimize else)))
((<ghil-begin> env loc exps)
(make-ghil-begin env loc (map optimize exps)))
((<ghil-bind> env loc vars vals body)
(make-ghil-bind env loc vars (map optimize vals) (optimize body)))
((<ghil-lambda> env loc vars rest meta body)
(make-ghil-lambda env loc vars rest meta (optimize body)))
((<ghil-inline> env loc instruction args)
(make-ghil-inline env loc instruction (map optimize args)))
((<ghil-call> env loc proc args)
(let ((parent-env env))
(record-case proc
;; ((@lambda (VAR...) BODY...) ARG...) =>
;; (@let ((VAR ARG) ...) BODY...)
((<ghil-lambda> env loc vars rest meta body)
(cond
((not rest)
(for-each (lambda (v)
(case (ghil-var-kind v)
((argument) (set! (ghil-var-kind v) 'local)))
(set! (ghil-var-env v) parent-env)
(ghil-env-add! parent-env v))
(ghil-env-variables env)))
(else
(make-ghil-call parent-env loc (optimize proc) (map optimize args)))))
(else
(make-ghil-call parent-env loc (optimize proc) (map optimize args))))))
(else x)))
;;;
;;; Stage 3: Code generation
;;;
(define *ia-void* (make-glil-void))
(define *ia-drop* (make-glil-call 'drop 0))
(define *ia-return* (make-glil-call 'return 0))
(define (make-label) (gensym ":L"))
(define (make-glil-var op env var)
(case (ghil-var-kind var)
((argument)
(make-glil-argument op (ghil-var-index var)))
((local)
(make-glil-local op (ghil-var-index var)))
((external)
(do ((depth 0 (1+ depth))
(e env (ghil-env-parent e)))
((eq? e (ghil-var-env var))
(make-glil-external op depth (ghil-var-index var)))))
((module)
(let ((env (ghil-var-env var)))
(make-glil-module op (ghil-mod-module (ghil-env-mod env))
(ghil-var-name var))))
(else (error "Unknown kind of variable:" var))))
(define (codegen ghil)
(let ((stack '()))
(define (push-code! loc code)
(set! stack (cons code stack))
(if loc (set! stack (cons (make-glil-source loc) stack))))
(define (push-bindings! loc vars)
(if (not (null? vars))
(push-code!
loc
(make-glil-bind
(map list
(map ghil-var-name vars)
(map ghil-var-kind vars)
(map ghil-var-index vars))))))
(define (comp tree tail drop)
(define (push-label! label)
(push-code! #f (make-glil-label label)))
(define (push-branch! loc inst label)
(push-code! loc (make-glil-branch inst label)))
(define (push-call! loc inst args)
(for-each comp-push args)
(push-code! loc (make-glil-call inst (length args))))
;; possible tail position
(define (comp-tail tree) (comp tree tail drop))
;; push the result
(define (comp-push tree) (comp tree #f #f))
;; drop the result
(define (comp-drop tree) (comp tree #f #t))
;; drop the result if unnecessary
(define (maybe-drop)
(if drop (push-code! #f *ia-drop*)))
;; return here if necessary
(define (maybe-return)
(if tail (push-code! #f *ia-return*)))
;; return this code if necessary
(define (return-code! loc code)
(if (not drop) (push-code! loc code))
(maybe-return))
;; return void if necessary
(define (return-void!)
(return-code! #f *ia-void*))
;; return object if necessary
(define (return-object! loc obj)
(return-code! loc (make-glil-const #:obj obj)))
;;
;; dispatch
(record-case tree
((<ghil-void>)
(return-void!))
((<ghil-quote> env loc obj)
(return-object! loc obj))
((<ghil-quasiquote> env loc exp)
(let loop ((x exp))
(cond
((list? x)
(push-call! #f 'mark '())
(for-each loop x)
(push-call! #f 'list-mark '()))
((pair? x)
(loop (car x))
(loop (cdr x))
(push-code! #f (make-glil-call 'cons 2)))
((record? x)
(record-case x
((<ghil-unquote> env loc exp)
(comp-push exp))
((<ghil-unquote-splicing> env loc exp)
(comp-push exp)
(push-call! #f 'list-break '()))))
(else
(push-code! #f (make-glil-const #:obj x)))))
(maybe-drop)
(maybe-return))
((<ghil-ref> env loc var)
(return-code! loc (make-glil-var 'ref env var)))
((<ghil-set> env loc var val)
(comp-push val)
(push-code! loc (make-glil-var 'set env var))
(return-void!))
((<ghil-define> env loc var val)
(comp-push val)
(push-code! loc (make-glil-var 'define env var))
(return-void!))
((<ghil-if> env loc test then else)
;; TEST
;; (br-if-not L1)
;; THEN
;; (br L2)
;; L1: ELSE
;; L2:
(let ((L1 (make-label)) (L2 (make-label)))
(comp-push test)
(push-branch! loc 'br-if-not L1)
(comp-tail then)
(if (not tail) (push-branch! #f 'br L2))
(push-label! L1)
(comp-tail else)
(if (not tail) (push-label! L2))))
((<ghil-and> env loc exps)
;; EXP
;; (br-if-not L1)
;; ...
;; TAIL
;; (br L2)
;; L1: (const #f)
;; L2:
(cond ((null? exps) (return-object! loc #t))
((null? (cdr exps)) (comp-tail (car exps)))
(else
(let ((L1 (make-label)) (L2 (make-label)))
(let lp ((exps exps))
(cond ((null? (cdr exps))
(comp-tail (car exps))
(push-branch! #f 'br L2)
(push-label! L1)
(return-object! #f #f)
(push-label! L2)
(maybe-return))
(else
(comp-push (car exps))
(push-branch! #f 'br-if-not L1)
(lp (cdr exps)))))))))
((<ghil-or> env loc exps)
;; EXP
;; (dup)
;; (br-if L1)
;; (drop)
;; ...
;; TAIL
;; L1:
(cond ((null? exps) (return-object! loc #f))
((null? (cdr exps)) (comp-tail (car exps)))
(else
(let ((L1 (make-label)))
(let lp ((exps exps))
(cond ((null? (cdr exps))
(comp-tail (car exps))
(push-label! L1)
(maybe-return))
(else
(comp-push (car exps))
(push-call! #f 'dup '())
(push-branch! #f 'br-if L1)
(push-call! #f 'drop '())
(lp (cdr exps)))))))))
((<ghil-begin> env loc exps)
;; EXPS...
;; TAIL
(if (null? exps)
(return-void!)
(do ((exps exps (cdr exps)))
((null? (cdr exps))
(comp-tail (car exps)))
(comp-drop (car exps)))))
((<ghil-bind> env loc vars vals body)
;; VALS...
;; (set VARS)...
;; BODY
(for-each comp-push vals)
(push-bindings! loc vars)
(for-each (lambda (var) (push-code! #f (make-glil-var 'set env var)))
(reverse vars))
(comp-tail body)
(push-code! #f (make-glil-unbind)))
((<ghil-lambda> env loc vars rest meta body)
(return-code! loc (codegen tree)))
((<ghil-inline> env loc inline args)
;; ARGS...
;; (INST NARGS)
(push-call! loc inline args)
(maybe-drop)
(maybe-return))
((<ghil-call> env loc proc args)
;; PROC
;; ARGS...
;; ([tail-]call NARGS)
(comp-push proc)
(push-call! loc (if tail 'tail-call 'call) args)
(maybe-drop))))
;;
;; main
(record-case ghil
((<ghil-lambda> env loc vars rest meta body)
(let* ((evars (ghil-env-variables env))
(locs (pick (lambda (v) (eq? (ghil-var-kind v) 'local)) evars))
(exts (pick (lambda (v) (eq? (ghil-var-kind v) 'external)) evars)))
;; initialize variable indexes
(finalize-index! vars)
(finalize-index! locs)
(finalize-index! exts)
;; meta bindings
(push-bindings! #f vars)
;; export arguments
(do ((n 0 (1+ n))
(l vars (cdr l)))
((null? l))
(let ((v (car l)))
(case (ghil-var-kind v)
((external)
(push-code! #f (make-glil-argument 'ref n))
(push-code! #f (make-glil-external 'set 0 (ghil-var-index v)))))))
;; compile body
(comp body #t #f)
;; create GLIL
(let ((vars (make-glil-vars :nargs (length vars)
:nrest (if rest 1 0)
:nlocs (length locs)
:nexts (length exts))))
(make-glil-asm vars meta (reverse! stack))))))))
(define (finalize-index! list)
(do ((n 0 (1+ n))
(l list (cdr l)))
((null? l))
(let ((v (car l))) (set! (ghil-var-index v) n))))