module/system/vm/frame.scm

   1 ;;; Guile VM frame functions
   2
   3 ;;; Copyright (C) 2001 Free Software Foundation, Inc.
   4 ;;; Copyright (C) 2005 Ludovic Courtès  <ludovic.courtes@laas.fr>
   5 ;;;
   6 ;;; This program is free software; you can redistribute it and/or modify
   7 ;;; it under the terms of the GNU General Public License as published by
   8 ;;; the Free Software Foundation; either version 2 of the License, or
   9 ;;; (at your option) any later version.
  10 ;;;
  11 ;;; This program is distributed in the hope that it will be useful,
  12 ;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 ;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 ;;; GNU General Public License for more details.
  15 ;;;
  16 ;;; You should have received a copy of the GNU General Public License
  17 ;;; along with this program; if not, write to the Free Software
  18 ;;; Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
  19
  20 ;;; Code:
  21
  22 (define-module (system vm frame)
  23   :use-module (system vm program)
  24   :use-module (system vm instruction)
  25   :use-module ((srfi srfi-1) :select (fold))
  26   :export (frame-number frame-address
  27            make-frame-chain
  28            print-frame print-frame-chain-as-backtrace
  29            frame-arguments frame-local-variables frame-external-variables
  30            frame-environment
  31            frame-variable-exists? frame-variable-ref frame-variable-set!
  32            frame-object-name
  33            frame-local-ref frame-external-link frame-local-set!
  34            frame-return-address frame-program
  35            frame-dynamic-link frame?))
  36
  37 (dynamic-call "scm_init_frames" (dynamic-link "libguile-vm"))
  38
  39 ;;;
  40 ;;; Frame chain
  41 ;;;
  42
  43 (define frame-number (make-object-property))
  44 (define frame-address (make-object-property))
  45
  46 (define (bootstrap-frame? frame)
  47   (let ((code (program-bytecode (frame-program frame))))
  48     (and (= (uniform-vector-length code) 3)
  49          (= (uniform-vector-ref code 2)
  50             (instruction->opcode 'halt)))))
  51
  52 (define (make-frame-chain frame addr)
  53   (define (make-rest)
  54     (make-frame-chain (frame-dynamic-link frame)
  55                       (frame-return-address frame)))
  56   (cond
  57    ((or (eq? frame #t) (eq? frame #f))
  58     ;; handle #f or #t dynamic links
  59     '())
  60    ((bootstrap-frame? frame)
  61     (make-rest))
  62    (else
  63     (let ((chain (make-rest)))
  64       (set! (frame-number frame) (length chain))
  65       (set! (frame-address frame)
  66             (- addr (program-base (frame-program frame))))
  67       (cons frame chain)))))
  68
  69 \f
  70 ;;;
  71 ;;; Pretty printing
  72 ;;;
  73
  74 (define (frame-line-number frame)
  75   (let ((addr (frame-address frame)))
  76     (cond ((assv addr (program-sources (frame-program frame)))
  77            => source:line)
  78           (else (format #f "@~a" addr)))))
  79
  80 (define (frame-file frame prev)
  81   (let ((sources (program-sources (frame-program frame))))
  82     (if (null? sources)
  83         prev
  84         (or (source:file (car sources))
  85             "current input"))))
  86
  87 (define (print-frame frame)
  88   (format #t "~4@a: ~a   ~a\n" (frame-line-number frame) (frame-number frame)
  89           (frame-call-representation frame)))
  90
  91
  92 (define (frame-call-representation frame)
  93   (define (abbrev x)
  94     (cond ((list? x)
  95            (if (> (length x) 3)
  96                (list (abbrev (car x)) (abbrev (cadr x)) '...)
  97                (map abbrev x)))
  98           ((pair? x)
  99            (cons (abbrev (car x)) (abbrev (cdr x))))
 100           ((vector? x)
 101            (case (vector-length x)
 102              ((0) x)
 103              ((1) (vector (abbrev (vector-ref x 0))))
 104              (else (vector (abbrev (vector-ref x 0)) '...))))
 105           (else x)))
 106   (abbrev (cons (program-name frame) (frame-arguments frame))))
 107
 108 (define (print-frame-chain-as-backtrace frames)
 109   (if (null? frames)
 110       (format #t "No backtrace available.\n")
 111       (begin
 112         (format #t "VM backtrace:\n")
 113         (fold (lambda (frame file)
 114                 (let ((new-file (frame-file frame file)))
 115                   (if (not (equal? new-file file))
 116                       (format #t "In ~a:\n" new-file))
 117                   (print-frame frame)
 118                   new-file))
 119               'no-file
 120               frames))))
 121
 122 (define (program-name frame)
 123   (let ((prog (frame-program frame))
 124         (link (frame-dynamic-link frame)))
 125     (or (object-property prog 'name)
 126         (and (frame? link)
 127              (frame-object-name link (1- (frame-address link)) prog))
 128         (hash-fold (lambda (s v d) (if (eq? prog (variable-ref v)) s d))
 129                    prog (module-obarray (current-module))))))
 130
 131 \f
 132 ;;;
 133 ;;; Frames
 134 ;;;
 135
 136 (define (frame-arguments frame)
 137   (let* ((prog (frame-program frame))
 138          (arity (program-arity prog)))
 139     (do ((n (+ (arity:nargs arity) -1) (1- n))
 140          (l '() (cons (frame-local-ref frame n) l)))
 141         ((< n 0) l))))
 142
 143 (define (frame-local-variables frame)
 144   (let* ((prog (frame-program frame))
 145          (arity (program-arity prog)))
 146     (do ((n (+ (arity:nargs arity) (arity:nlocs arity) -1) (1- n))
 147          (l '() (cons (frame-local-ref frame n) l)))
 148         ((< n 0) l))))
 149
 150 (define (frame-external-variables frame)
 151   (frame-external-link frame))
 152
 153 (define (frame-external-ref frame index)
 154   (list-ref (frame-external-link frame) index))
 155
 156 (define (frame-external-set! frame index val)
 157   (list-set! (frame-external-link frame) index val))
 158
 159 (define (frame-binding-ref frame binding)
 160   (if (binding:extp binding)
 161     (frame-external-ref frame (binding:index binding))
 162     (frame-local-ref frame (binding:index binding))))
 163
 164 (define (frame-binding-set! frame binding val)
 165   (if (binding:extp binding)
 166     (frame-external-set! frame (binding:index binding) val)
 167     (frame-local-set! frame (binding:index binding) val)))
 168
 169 (define (frame-bindings frame addr)
 170   (do ((bs (program-bindings (frame-program frame)) (cdr bs))
 171        (ls '() (if (cdar bs) (cons (cdar bs) ls) (cdr ls))))
 172       ((or (null? bs) (> (caar bs) addr))
 173        (apply append ls))))
 174
 175 (define (frame-lookup-binding frame addr sym)
 176   (do ((bs (frame-bindings frame addr) (cdr bs)))
 177       ((or (null? bs) (eq? sym (binding:name (car bs))))
 178        (and (pair? bs) (car bs)))))
 179
 180 (define (frame-object-binding frame addr obj)
 181   (do ((bs (frame-bindings frame addr) (cdr bs)))
 182       ((or (null? bs) (eq? obj (frame-binding-ref frame (car bs))))
 183        (and (pair? bs) (car bs)))))
 184
 185 (define (frame-environment frame addr)
 186   (map (lambda (binding)
 187          (cons (binding:name binding) (frame-binding-ref frame binding)))
 188        (frame-bindings frame addr)))
 189
 190 (define (frame-variable-exists? frame addr sym)
 191   (if (frame-lookup-binding frame addr sym) #t #f))
 192
 193 (define (frame-variable-ref frame addr sym)
 194   (cond ((frame-lookup-binding frame addr sym) =>
 195          (lambda (binding) (frame-binding-ref frame binding)))
 196         (else (error "Unknown variable:" sym))))
 197
 198 (define (frame-variable-set! frame addr sym val)
 199   (cond ((frame-lookup-binding frame addr sym) =>
 200          (lambda (binding) (frame-binding-set! frame binding val)))
 201         (else (error "Unknown variable:" sym))))
 202
 203 (define (frame-object-name frame addr obj)
 204   (cond ((frame-object-binding frame addr obj) => binding:name)
 205         (else #f)))