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;;; Guile VM debugging facilities
;;; Copyright (C) 2001, 2009, 2010 Free Software Foundation, Inc.
;;;
;;; This library is free software; you can redistribute it and/or
;;; modify it under the terms of the GNU Lesser General Public
;;; License as published by the Free Software Foundation; either
;;; version 3 of the License, or (at your option) any later version.
;;;
;;; This library 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
;;; Lesser General Public License for more details.
;;;
;;; You should have received a copy of the GNU Lesser General Public
;;; License along with this library; if not, write to the Free Software
;;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
;;; Code:
(define-module (system repl debug)
#:use-module (system base pmatch)
#:use-module (system base syntax)
#:use-module (system base language)
#:use-module (system vm vm)
#:use-module (system vm frame)
#:use-module (ice-9 rdelim)
#:use-module (ice-9 pretty-print)
#:use-module (ice-9 format)
#:use-module ((system vm inspect) #:select ((inspect . %inspect)))
#:use-module (system vm program)
#:export (<debug>
make-debug debug? debug-frames debug-index
print-locals print-frame print-frames frame->module
stack->vector narrow-stack->vector))
;;; FIXME: add more repl meta-commands: continue, inspect, etc...
;;;
;;; Debugger
;;;
;;; The actual interaction loop of the debugger is run by the repl. This module
;;; simply exports a data structure to hold the debugger state, along with its
;;; accessors, and provides some helper functions.
;;;
(define-record <debug> frames index)
(define (reverse-hashq h)
(let ((ret (make-hash-table)))
(hash-for-each
(lambda (k v)
(hashq-set! ret v (cons k (hashq-ref ret v '()))))
h)
ret))
(define* (print-locals frame #:optional (port (current-output-port))
#:key (width 72) (per-line-prefix ""))
(let ((bindings (frame-bindings frame)))
(cond
((null? bindings)
(format port "~aNo local variables.~%" per-line-prefix))
(else
(format port "~aLocal variables:~%" per-line-prefix)
(for-each
(lambda (binding)
(format port "~a~4d ~a~:[~; (boxed)~] = ~v:@y\n"
per-line-prefix
(binding:index binding)
(binding:name binding)
(binding:boxed? binding)
width
(let ((x (frame-local-ref frame (binding:index binding))))
(if (binding:boxed? binding)
(variable-ref x)
x))))
(frame-bindings frame))))))
(define* (print-frame frame #:optional (port (current-output-port))
#:key index (width 72) (full? #f) (last-source #f))
(define (source:pretty-file source)
(if source
(or (source:file source) "current input")
"unknown file"))
(let* ((source (frame-source frame))
(file (source:pretty-file source))
(line (and=> source source:line)))
(if (and file (not (equal? file (source:pretty-file last-source))))
(format port "~&In ~a:~&" file))
(format port "~:[~*~6_~;~5d:~]~:[~*~3_~;~3d~] ~v:@y~%"
line line index index width (frame-call-representation frame))
(if full?
(print-locals frame #:width width
#:per-line-prefix " "))))
(define* (print-frames frames
#:optional (port (current-output-port))
#:key (width 72) (full? #f) (forward? #f) count)
(let* ((len (vector-length frames))
(lower-idx (if (or (not count) (positive? count))
0
(max 0 (+ len count))))
(upper-idx (if (and count (negative? count))
(1- len)
(1- (if count (min count len) len))))
(inc (if forward? 1 -1)))
(let lp ((i (if forward? lower-idx upper-idx))
(last-source #f))
(if (<= lower-idx i upper-idx)
(let* ((frame (vector-ref frames i)))
(print-frame frame port #:index i #:width width #:full? full?
#:last-source last-source)
(lp (+ i inc) (frame-source frame)))))))
;; Ideally here we would have something much more syntactic, in that a set! to a
;; local var that is not settable would raise an error, and export etc forms
;; would modify the module in question: but alack, this is what we have now.
;; Patches welcome!
(define (frame->module frame)
(let ((proc (frame-procedure frame)))
(if (program? proc)
(let* ((mod (or (program-module proc) (current-module)))
(mod* (make-module)))
(module-use! mod* mod)
(for-each
(lambda (binding)
(let* ((x (frame-local-ref frame (binding:index binding)))
(var (if (binding:boxed? binding) x (make-variable x))))
(format #t
"~:[Read-only~;Mutable~] local variable ~a = ~70:@y\n"
(binding:boxed? binding)
(binding:name binding)
(if (variable-bound? var) (variable-ref var) var))
(module-add! mod* (binding:name binding) var)))
(frame-bindings frame))
mod*)
(current-module))))
;; TODO:
;;
;; eval expression in context of frame
;; set local variable in frame
;; step until next instruction
;; step until next function call/return
;; step until return from frame
;; step until different source line
;; step until greater source line
;; watch expression
;; break on a function
;; remove breakpoints
;; set printing width
;; display a truncated backtrace
;; go to a frame by index
;; (reuse gdb commands perhaps)
;; disassemble a function
;; disassemble the current function
;; inspect any object
;; hm, trace via reassigning global vars. tricksy.
;; (state associated with vm ?)
(define (stack->vector stack)
(let* ((len (stack-length stack))
(v (make-vector len)))
(if (positive? len)
(let lp ((i 0) (frame (stack-ref stack 0)))
(if (< i len)
(begin
(vector-set! v i frame)
(lp (1+ i) (frame-previous frame))))))
v))
(define (narrow-stack->vector stack . args)
(stack->vector (apply make-stack (stack-ref stack 0) args)))
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