(symbol-file-load-history-loaded): Variable renamed,

and defvar moved from loadhist.el.
(symbol-file): Renamed from describe-function-find-file.
Load fns-VERSION.el here.
(describe-variable, describe-function-1): Use symbol-file.

1 files changed, 23 insertions, 3 deletions

diff --git a/lisp/help.el b/lisp/help.el
index 1347fdf1abf..ddc67c43432 100644
--- a/lisp/help.el
+++ b/lisp/help.el
@@ -541,7 +541,27 @@ C-w Display information on absence of warranty for GNU Emacs."
               (error nil)))
       (set-syntax-table stab))))
 
-(defun describe-function-find-file (function)
+(defvar symbol-file-load-history-loaded nil
+  "Non-nil means we have loaded the file `fns-VERSION.el' in `exec-directory'.
+That file records the part of `load-history' for preloaded files,
+which is cleared out before dumping to make Emacs smaller.")
+
+(defun symbol-file (function)
+  "Return the input source from which SYM was loaded.
+The value is normally a string that was passed to `load':
+either an absolute file name, or a library name
+\(with no directory name and no `.el' or `.elc' at the end).
+It can also be nil, if the definition is not associated with any file."
+  (unless symbol-file-load-history-loaded
+    (load (expand-file-name
+           ;; fns-XX.YY.ZZ.el does not work on DOS filesystem.
+           (if (eq system-type 'ms-dos)
+               "fns.el"
+             (format "fns-%s.el" emacs-version))
+           exec-directory)
+          ;; The file name fns-%s.el already has a .el extension.
+          nil nil t)
+    (setq symbol-file-load-history-loaded t))
   (let ((files load-history)
         file functions)
     (while files
@@ -610,7 +630,7 @@ C-w Display information on absence of warranty for GNU Emacs."
       (princ "("))
     (princ string)
     (or file-name
-        (setq file-name (describe-function-find-file function)))
+        (setq file-name (symbol-file function)))
     (if file-name
         (progn
           (princ " in `")
@@ -749,7 +769,7 @@ Returns the documentation as a string, also."
           ;; Make a hyperlink to the library if appropriate.  (Don't
           ;; change the format of the buffer's initial line in case
           ;; anything expects the current format.)
-          (let ((file-name (describe-function-find-file variable)))
+          (let ((file-name (symbol-file variable)))
             (when file-name
               (princ "\n\nDefined in `")
               (princ file-name)