/usr/share/gdb/auto-load/libguile-2.0.so.22.8.1-gdb.scm is in guile-2.0-dev 2.0.13+1-5build2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 | ;;; GDB debugging support for Guile.
;;;
;;; Copyright 2014, 2015 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 3 of the License, 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. If not, see <http://www.gnu.org/licenses/>.
(define-module (guile-gdb)
#:use-module (system base types)
#:use-module ((gdb) #:hide (symbol?))
#:use-module (gdb printing)
#:use-module (srfi srfi-11)
#:use-module (ice-9 match)
#:export (%gdb-memory-backend
display-vm-frames))
;;; Commentary:
;;;
;;; This file defines GDB extensions to pretty-print 'SCM' objects, and
;;; to walk Guile's virtual machine stack.
;;;
;;; This file is installed under a name that follows the convention that
;;; allows GDB to auto-load it anytime the user is debugging libguile
;;; (info "(gdb) objfile-gdbdotext file").
;;;
;;; Code:
(define (type-name-from-descriptor descriptor-array type-number)
"Return the name of the type TYPE-NUMBER as seen in DESCRIPTOR-ARRAY, or #f
if the information is not available."
(let ((descriptors (lookup-global-symbol descriptor-array)))
(and descriptors
(let ((code (type-code (symbol-type descriptors))))
(or (= TYPE_CODE_ARRAY code)
(= TYPE_CODE_PTR code)))
(let* ((type-descr (value-subscript (symbol-value descriptors)
type-number))
(name (value-field type-descr "name")))
(value->string name)))))
(define (scm-value->integer value)
"Return the integer value of VALUE, which is assumed to be a GDB value
corresponding to an 'SCM' object."
(let ((type (type-strip-typedefs (value-type value))))
(cond ((= (type-code type) TYPE_CODE_UNION)
;; SCM_DEBUG_TYPING_STRICTNESS = 2
(value->integer (value-field (value-field value "n")
"n")))
(else
;; SCM_DEBUG_TYPING_STRICTNESS = 1
(value->integer value)))))
(define %gdb-memory-backend
;; The GDB back-end to access the inferior's memory.
(let ((void* (type-pointer (lookup-type "void"))))
(define (dereference-word address)
;; Return the word at ADDRESS.
(value->integer
(value-dereference (value-cast (make-value address)
(type-pointer void*)))))
(define (open address size)
;; Return a port to the SIZE bytes starting at ADDRESS.
(if size
(open-memory #:start address #:size size)
(open-memory #:start address)))
(define (type-name kind number)
;; Return the type name of KIND type NUMBER.
(type-name-from-descriptor (case kind
((smob) "scm_smobs")
((port) "scm_ptobs"))
number))
(memory-backend dereference-word open type-name)))
;;;
;;; GDB pretty-printer registration.
;;;
(define (make-scm-pretty-printer-worker obj)
(define (list->iterator list)
(make-iterator list list
(let ((n 0))
(lambda (iter)
(match (iterator-progress iter)
(() (end-of-iteration))
((elt . list)
(set-iterator-progress! iter list)
(let ((name (format #f "[~a]" n)))
(set! n (1+ n))
(cons name (object->string elt)))))))))
(cond
((string? obj)
(make-pretty-printer-worker
"string" ; display hint
(lambda (printer) obj)
#f))
((and (array? obj)
(match (array-shape obj)
(((0 _)) #t)
(_ #f)))
(make-pretty-printer-worker
"array" ; display hint
(lambda (printer)
(let ((tag (array-type obj)))
(case tag
((#t) "#<vector>")
((b) "#<bitvector>")
(else (format #f "#<~avector>" tag)))))
(lambda (printer)
(list->iterator (array->list obj)))))
((inferior-struct? obj)
(make-pretty-printer-worker
"array" ; display hint
(lambda (printer)
(format #f "#<struct ~a>" (inferior-struct-name obj)))
(lambda (printer)
(list->iterator (inferior-struct-fields obj)))))
(else
(make-pretty-printer-worker
#f ; display hint
(lambda (printer)
(object->string obj))
#f))))
(define %scm-pretty-printer
(make-pretty-printer
"SCM"
(lambda (pp value)
(let ((name (type-name (value-type value))))
(and (and name (string=? name "SCM"))
(make-scm-pretty-printer-worker
(scm->object (scm-value->integer value) %gdb-memory-backend)))))))
(define* (register-pretty-printer #:optional objfile)
(prepend-pretty-printer! objfile %scm-pretty-printer))
(register-pretty-printer)
;;;
;;; VM stack walking.
;;;
(define (find-vm-engine-frame)
"Return the bottom-most frame containing a call to the VM engine."
(define (vm-engine-frame? frame)
(let ((sym (frame-function frame)))
(and sym
(member (symbol-name sym)
'("vm_debug_engine" "vm_regular_engine")))))
(let loop ((frame (newest-frame)))
(and frame
(if (vm-engine-frame? frame)
frame
(loop (frame-older frame))))))
(define (vm-stack-pointer)
"Return the current value of the VM stack pointer or #f."
(let ((frame (find-vm-engine-frame)))
(and frame
(frame-read-var frame "sp"))))
(define (vm-frame-pointer)
"Return the current value of the VM frame pointer or #f."
(let ((frame (find-vm-engine-frame)))
(and frame
(frame-read-var frame "fp"))))
(define* (display-vm-frames #:optional (port (current-output-port)))
"Display the VM frames on PORT."
(define (display-objects start end)
;; Display all the objects (arguments and local variables) located
;; between START and END.
(let loop ((number 0)
(address start))
(when (and (> start 0) (<= address end))
(let ((object (dereference-word %gdb-memory-backend address)))
;; TODO: Push onto GDB's value history.
(format port " slot ~a -> ~s~%"
number (scm->object object %gdb-memory-backend)))
(loop (+ 1 number) (+ address %word-size)))))
(let loop ((number 0)
(sp (value->integer (vm-stack-pointer)))
(fp (value->integer (vm-frame-pointer))))
(unless (zero? fp)
(let-values (((ra mvra link proc)
(vm-frame fp %gdb-memory-backend)))
(format port "#~a ~s~%" number (scm->object proc %gdb-memory-backend))
(display-objects fp sp)
(loop (+ 1 number) (- fp (* 5 %word-size)) link)))))
;; See libguile/frames.h.
(define* (vm-frame fp #:optional (backend %gdb-memory-backend))
"Return the components of the stack frame at FP."
(let ((caller (dereference-word backend (- fp %word-size)))
(ra (dereference-word backend (- fp (* 2 %word-size))))
(mvra (dereference-word backend (- fp (* 3 %word-size))))
(link (dereference-word backend (- fp (* 4 %word-size)))))
(values ra mvra link caller)))
;;; libguile-2.0-gdb.scm ends here
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