;;;
;;; Known deficiencies:
;;;
-;;; * flags CATCH tags as stale;
-;;; * flags constants (under certain circumstances) as stale;
;;; * output is not necessarily terribly clear;
;;; * takes a long time (several hours on CSR's 300MHz x86 desktop) to
;;; run.
+;;;
+;;; Comment from Eric Marsden:
+;;;
+;;; This file contains code that attempts to identify symbols in a
+;;; CMUCL image that are stale. For example, the package descriptions
+;;; in src/code/package.lisp can get out of sync with the source code,
+;;; leading to symbols that are exported without being used anywhere.
+;;;
+;;; The routines work by walking all the objects allocated in a heap
+;;; image (using the function VM::MAP-ALLOCATED-OBJECTS). For each
+;;; object of type symbol, it scans the entire heap for objects that
+;;; reference that symbol. If it finds no references, or if there is
+;;; only one reference that looks like it is likely from the internals
+;;; of a package-related datastructure, the name of the symbol and its
+;;; package is displayed.
+;;;
+;;; The "references to that symbol" are found using the function
+;;; SB-VM::MAP-REFERENCING-OBJECTS. Consider for example a function
+;;; that uses the value of a symbol. The code-object for that function
+;;; contains a reference to the symbol, so that a call to SYMBOL-VALUE
+;;; can be made at runtime. The data structures corresponding to a
+;;; package must maintain a list of its exported an imported symbols.
+;;; They contain a hashtable, which contains a vector, which contains
+;;; symbols. So all exported symbols will have at least one
+;;; referencing object: a vector related to some package.
+;;;
+;;; Limitations: these routines may provide a number of false
+;;; positives (symbols that are not actually stale). There are also a
+;;; number of PCL-related symbols that are displayed, but probably
+;;; used internally by PCL. Moral: the output of these routines must
+;;; be checked carefully before going on a code deletion spree.
(defun print-stale-reference (obj stream)
(cond ((vectorp obj)
(format stream "vector (probable package internals)"))
- ((sb-c::compiled-debug-function-p obj)
- (format stream "#<compiled-debug-function ~a>"
- (sb-c::compiled-debug-function-name obj)))
+ ((sb-c::compiled-debug-fun-p obj)
+ (format stream "#<compiled-debug-fun ~A>"
+ (sb-c::compiled-debug-fun-name obj)))
+ ((sb-kernel:code-component-p obj)
+ (format stream "#<code ~A>"
+ (let ((dinfo (sb-kernel:%code-debug-info obj)))
+ (cond
+ ((eq dinfo :bogus-lra) "BOGUS-LRA")
+ (t (sb-c::debug-info-name dinfo))))))
(t
(format stream "~w" obj))))
+(defun external-symbol-p (obj)
+ (declare (type symbol obj))
+ (let ((package (symbol-package obj)))
+ (and package
+ (eq (nth-value 1 (find-symbol (symbol-name obj) package))
+ :external))))
+
(defun find-stale-objects ()
(dolist (space '(:static :dynamic :read-only))
(sb-vm::map-allocated-objects
(lambda (obj type size)
(declare (optimize (safety 0))
(ignore size))
- (when (eql type sb-vm:symbol-header-widetag)
- (ignore-errors
- (let ((read-only-space-refs (sb-vm::list-referencing-objects :read-only obj))
- (static-space-refs (sb-vm::list-referencing-objects :static obj))
- (dynamic-space-refs (sb-vm::list-referencing-objects :dynamic obj)))
- (when (>= 1 (+ (length read-only-space-refs)
- (length static-space-refs)
- (length dynamic-space-refs)))
- (format t "Symbol ~a::~a~%"
- (and (symbol-package obj) (package-name (symbol-package obj)))
- (symbol-name obj))
- (unless (null read-only-space-refs)
- (princ " Reference in read-only space: ")
- (print-stale-reference (car read-only-space-refs) t)
- (terpri))
- (unless (null static-space-refs)
- (princ " Reference in static space: ")
- (print-stale-reference (car static-space-refs) t)
- (terpri))
- (unless (null dynamic-space-refs)
- (princ " Reference in dynamic space: ")
- (print-stale-reference (car dynamic-space-refs) t)
- (terpri)))))))
+ (block mapper
+ (when (eql type sb-vm:symbol-header-widetag)
+ (ignore-errors
+ (let ((refs (let ((res nil)
+ (count 0))
+ (dolist (space '(:static :dynamic :read-only))
+ (sb-vm::map-referencing-objects
+ (lambda (o)
+ (when (> (incf count) 1)
+ (return-from mapper nil))
+ (push (cons space o) res))
+ space obj))
+ res)))
+ (let ((externalp (external-symbol-p obj)))
+ (format t "~:[S~;External s~]ymbol ~:[#~;~:*~A:~]~2:*~:[:~;~]~*~A~%"
+ externalp
+ (and (symbol-package obj)
+ (package-name (symbol-package obj)))
+ (symbol-name obj)))
+ (if (null refs)
+ (progn (princ " No references found") (terpri))
+ (progn
+ (ecase (caar refs)
+ (:read-only
+ (princ " Reference in read-only space: "))
+ (:static
+ (princ " Reference in static space: "))
+ (:dynamic
+ (princ " Reference in dynamic space: ")))
+ (print-stale-reference (cdar refs) t)
+ (terpri))))))))
space)))