root/trunk/lisp/emacs-lisp/bytecomp.el

;;; bytecomp.el --- compilation of Lisp code into byte code

;; Copyright (C) 1985, 1986, 1987, 1992, 1994, 1998, 2000, 2001, 2002,
;;   2003, 2004, 2005, 2006, 2007, 2008 Free Software Foundation, Inc.

;; Author: Jamie Zawinski <jwz@lucid.com>
;;      Hallvard Furuseth <hbf@ulrik.uio.no>
;; Maintainer: FSF
;; Keywords: lisp

;; This file is part of GNU Emacs.

;; GNU Emacs 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, or (at your option)
;; any later version.

;; GNU Emacs 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 GNU Emacs; see the file COPYING.  If not, write to the
;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
;; Boston, MA 02110-1301, USA.

;;; Commentary:

;; The Emacs Lisp byte compiler.  This crunches lisp source into a sort
;; of p-code (`lapcode') which takes up less space and can be interpreted
;; faster.  [`LAP' == `Lisp Assembly Program'.]
;; The user entry points are byte-compile-file and byte-recompile-directory.

;;; Code:

;; ========================================================================
;; Entry points:
;;      byte-recompile-directory, byte-compile-file,
;;     batch-byte-compile, batch-byte-recompile-directory,
;;      byte-compile, compile-defun,
;;      display-call-tree
;; (byte-compile-buffer and byte-compile-and-load-file were turned off
;;  because they are not terribly useful and get in the way of completion.)

;; This version of the byte compiler has the following improvements:
;;  + optimization of compiled code:
;;    - removal of unreachable code;
;;    - removal of calls to side-effectless functions whose return-value
;;      is unused;
;;    - compile-time evaluation of safe constant forms, such as (consp nil)
;;      and (ash 1 6);
;;    - open-coding of literal lambdas;
;;    - peephole optimization of emitted code;
;;    - trivial functions are left uncompiled for speed.
;;  + support for inline functions;
;;  + compile-time evaluation of arbitrary expressions;
;;  + compile-time warning messages for:
;;    - functions being redefined with incompatible arglists;
;;    - functions being redefined as macros, or vice-versa;
;;    - functions or macros defined multiple times in the same file;
;;    - functions being called with the incorrect number of arguments;
;;    - functions being called which are not defined globally, in the
;;      file, or as autoloads;
;;    - assignment and reference of undeclared free variables;
;;    - various syntax errors;
;;  + correct compilation of nested defuns, defmacros, defvars and defsubsts;
;;  + correct compilation of top-level uses of macros;
;;  + the ability to generate a histogram of functions called.

;; User customization variables:
;;
;; byte-compile-verbose Whether to report the function currently being
;;                              compiled in the echo area;
;; byte-optimize                Whether to do optimizations; this may be
;;                              t, nil, 'source, or 'byte;
;; byte-optimize-log            Whether to report (in excruciating detail)
;;                              exactly which optimizations have been made.
;;                              This may be t, nil, 'source, or 'byte;
;; byte-compile-error-on-warn   Whether to stop compilation when a warning is
;;                              produced;
;; byte-compile-delete-errors   Whether the optimizer may delete calls or
;;                              variable references that are side-effect-free
;;                              except that they may return an error.
;; byte-compile-generate-call-tree      Whether to generate a histogram of
;;                              function calls.  This can be useful for
;;                              finding unused functions, as well as simple
;;                              performance metering.
;; byte-compile-warnings        List of warnings to issue, or t.  May contain
;;                              `free-vars' (references to variables not in the
;;                                           current lexical scope)
;;                              `unresolved' (calls to unknown functions)
;;                              `callargs'  (lambda calls with args that don't
;;                                           match the lambda's definition)
;;                              `redefine'  (function cell redefined from
;;                                           a macro to a lambda or vice versa,
;;                                           or redefined to take other args)
;;                              `obsolete'  (obsolete variables and functions)
;;                              `noruntime' (calls to functions only defined
;;                                           within `eval-when-compile')
;;                              `cl-warnings' (calls to CL functions)
;;                              `interactive-only' (calls to commands that are
;;                                                 not good to call from Lisp)
;; byte-compile-compatibility   Whether the compiler should
;;                              generate .elc files which can be loaded into
;;                              generic emacs 18.
;; emacs-lisp-file-regexp       Regexp for the extension of source-files;
;;                              see also the function byte-compile-dest-file.

;; New Features:
;;
;;  o   The form `defsubst' is just like `defun', except that the function
;;      generated will be open-coded in compiled code which uses it.  This
;;      means that no function call will be generated, it will simply be
;;      spliced in.  Lisp functions calls are very slow, so this can be a
;;      big win.
;;
;;      You can generally accomplish the same thing with `defmacro', but in
;;      that case, the defined procedure can't be used as an argument to
;;      mapcar, etc.
;;
;;  o   You can also open-code one particular call to a function without
;;      open-coding all calls.  Use the 'inline' form to do this, like so:
;;
;;              (inline (foo 1 2 3))    ;; `foo' will be open-coded
;;      or...
;;              (inline                 ;;  `foo' and `baz' will be
;;               (foo 1 2 3 (bar 5))    ;; open-coded, but `bar' will not.
;;               (baz 0))
;;
;;  o   It is possible to open-code a function in the same file it is defined
;;      in without having to load that file before compiling it.  The
;;      byte-compiler has been modified to remember function definitions in
;;      the compilation environment in the same way that it remembers macro
;;      definitions.
;;
;;  o  Forms like ((lambda ...) ...) are open-coded.
;;
;;  o  The form `eval-when-compile' is like progn, except that the body
;;     is evaluated at compile-time.  When it appears at top-level, this
;;     is analogous to the Common Lisp idiom (eval-when (compile) ...).
;;     When it does not appear at top-level, it is similar to the
;;     Common Lisp #. reader macro (but not in interpreted code).
;;
;;  o  The form `eval-and-compile' is similar to eval-when-compile, but
;;      the whole form is evalled both at compile-time and at run-time.
;;
;;  o  The command compile-defun is analogous to eval-defun.
;;
;;  o  If you run byte-compile-file on a filename which is visited in a
;;     buffer, and that buffer is modified, you are asked whether you want
;;     to save the buffer before compiling.
;;
;;  o  byte-compiled files now start with the string `;ELC'.
;;     Some versions of `file' can be customized to recognize that.

(require 'backquote)

(or (fboundp 'defsubst)
    ;; This really ought to be loaded already!
    (load "byte-run"))

;; The feature of compiling in a specific target Emacs version
;; has been turned off because compile time options are a bad idea.
(defmacro byte-compile-single-version () nil)
(defmacro byte-compile-version-cond (cond) cond)

;; The crud you see scattered through this file of the form
;;   (or (and (boundp 'epoch::version) epoch::version)
;;        (string-lessp emacs-version "19"))
;; is because the Epoch folks couldn't be bothered to follow the
;; normal emacs version numbering convention.

;; (if (byte-compile-version-cond
;;      (or (and (boundp 'epoch::version) epoch::version)
;;       (string-lessp emacs-version "19")))
;;     (progn
;;       ;; emacs-18 compatibility.
;;       (defvar baud-rate (baud-rate)) ;Define baud-rate if it's undefined
;;
;;       (if (byte-compile-single-version)
;;        (defmacro byte-code-function-p (x) "Emacs 18 doesn't have these." nil)
;;      (defun byte-code-function-p (x) "Emacs 18 doesn't have these." nil))
;;
;;       (or (and (fboundp 'member)
;;             ;; avoid using someone else's possibly bogus definition of this.
;;             (subrp (symbol-function 'member)))
;;        (defun member (elt list)
;;          "like memq, but uses equal instead of eq.  In v19, this is a subr."
;;          (while (and list (not (equal elt (car list))))
;;            (setq list (cdr list)))
;;          list))))


(defgroup bytecomp nil
  "Emacs Lisp byte-compiler."
  :group 'lisp)

(defcustom emacs-lisp-file-regexp (if (eq system-type 'vax-vms)
                                      "\\.EL\\(;[0-9]+\\)?$"
                                    "\\.el$")
  "*Regexp which matches Emacs Lisp source files.
You may want to redefine the function `byte-compile-dest-file'
if you change this variable."
  :group 'bytecomp
  :type 'regexp)

;; This enables file name handlers such as jka-compr
;; to remove parts of the file name that should not be copied
;; through to the output file name.
(defun byte-compiler-base-file-name (filename)
  (let ((handler (find-file-name-handler filename
                                         'byte-compiler-base-file-name)))
    (if handler
        (funcall handler 'byte-compiler-base-file-name filename)
      filename)))

(or (fboundp 'byte-compile-dest-file)
    ;; The user may want to redefine this along with emacs-lisp-file-regexp,
    ;; so only define it if it is undefined.
    (defun byte-compile-dest-file (filename)
      "Convert an Emacs Lisp source file name to a compiled file name.
If FILENAME matches `emacs-lisp-file-regexp' (by default, files
with the extension `.el'), add `c' to it; otherwise add `.elc'."
      (setq filename (byte-compiler-base-file-name filename))
      (setq filename (file-name-sans-versions filename))
      (cond ((eq system-type 'vax-vms)
             (concat (substring filename 0 (string-match ";" filename)) "c"))
            ((string-match emacs-lisp-file-regexp filename)
             (concat (substring filename 0 (match-beginning 0)) ".elc"))
            (t (concat filename ".elc")))))

;; This can be the 'byte-compile property of any symbol.
(autoload 'byte-compile-inline-expand "byte-opt")

;; This is the entrypoint to the lapcode optimizer pass1.
(autoload 'byte-optimize-form "byte-opt")
;; This is the entrypoint to the lapcode optimizer pass2.
(autoload 'byte-optimize-lapcode "byte-opt")
(autoload 'byte-compile-unfold-lambda "byte-opt")

;; This is the entry point to the decompiler, which is used by the
;; disassembler.  The disassembler just requires 'byte-compile, but
;; that doesn't define this function, so this seems to be a reasonable
;; thing to do.
(autoload 'byte-decompile-bytecode "byte-opt")

(defcustom byte-compile-verbose
  (and (not noninteractive) (> baud-rate search-slow-speed))
  "*Non-nil means print messages describing progress of byte-compiler."
  :group 'bytecomp
  :type 'boolean)

(defcustom byte-compile-compatibility nil
  "*Non-nil means generate output that can run in Emacs 18.
This only means that it can run in principle, if it doesn't require
facilities that have been added more recently."
  :group 'bytecomp
  :type 'boolean)

;; (defvar byte-compile-generate-emacs19-bytecodes
;;         (not (or (and (boundp 'epoch::version) epoch::version)
;;               (string-lessp emacs-version "19")))
;;   "*If this is true, then the byte-compiler will generate bytecode which
;; makes use of byte-ops which are present only in Emacs 19.  Code generated
;; this way can never be run in Emacs 18, and may even cause it to crash.")

(defcustom byte-optimize t
  "*Enable optimization in the byte compiler.
Possible values are:
  nil      - no optimization
  t        - all optimizations
  `source' - source-level optimizations only
  `byte'   - code-level optimizations only"
  :group 'bytecomp
  :type '(choice (const :tag "none" nil)
                 (const :tag "all" t)
                 (const :tag "source-level" source)
                 (const :tag "byte-level" byte)))

(defcustom byte-compile-delete-errors nil
  "*If non-nil, the optimizer may delete forms that may signal an error.
This includes variable references and calls to functions such as `car'."
  :group 'bytecomp
  :type 'boolean)

(defvar byte-compile-dynamic nil
  "If non-nil, compile function bodies so they load lazily.
They are hidden in comments in the compiled file,
and each one is brought into core when the
function is called.

To enable this option, make it a file-local variable
in the source file you want it to apply to.
For example, add  -*-byte-compile-dynamic: t;-*- on the first line.

When this option is true, if you load the compiled file and then move it,
the functions you loaded will not be able to run.")
;;;###autoload(put 'byte-compile-dynamic 'safe-local-variable 'booleanp)

(defvar byte-compile-disable-print-circle nil
  "If non-nil, disable `print-circle' on printing a byte-compiled code.")
;;;###autoload(put 'byte-compile-disable-print-circle 'safe-local-variable 'booleanp)

(defcustom byte-compile-dynamic-docstrings t
  "*If non-nil, compile doc strings for lazy access.
We bury the doc strings of functions and variables
inside comments in the file, and bring them into core only when they
are actually needed.

When this option is true, if you load the compiled file and then move it,
you won't be able to find the documentation of anything in that file.

To disable this option for a certain file, make it a file-local variable
in the source file.  For example, add this to the first line:
  -*-byte-compile-dynamic-docstrings:nil;-*-
You can also set the variable globally.

This option is enabled by default because it reduces Emacs memory usage."
  :group 'bytecomp
  :type 'boolean)
;;;###autoload(put 'byte-compile-dynamic-docstrings 'safe-local-variable 'booleanp)

(defcustom byte-optimize-log nil
  "*If true, the byte-compiler will log its optimizations into *Compile-Log*.
If this is 'source, then only source-level optimizations will be logged.
If it is 'byte, then only byte-level optimizations will be logged."
  :group 'bytecomp
  :type '(choice (const :tag "none" nil)
                 (const :tag "all" t)
                 (const :tag "source-level" source)
                 (const :tag "byte-level" byte)))

(defcustom byte-compile-error-on-warn nil
  "*If true, the byte-compiler reports warnings with `error'."
  :group 'bytecomp
  :type 'boolean)

(defconst byte-compile-warning-types
  '(redefine callargs free-vars unresolved
             obsolete noruntime cl-functions interactive-only)
  "The list of warning types used when `byte-compile-warnings' is t.")
(defcustom byte-compile-warnings t
  "*List of warnings that the byte-compiler should issue (t for all).

Elements of the list may be:

  free-vars   references to variables not in the current lexical scope.
  unresolved  calls to unknown functions.
  callargs    function calls with args that don't match the definition.
  redefine    function name redefined from a macro to ordinary function or vice
              versa, or redefined to take a different number of arguments.
  obsolete    obsolete variables and functions.
  noruntime   functions that may not be defined at runtime (typically
              defined only under `eval-when-compile').
  cl-functions    calls to runtime functions from the CL package (as
                  distinguished from macros and aliases).
  interactive-only
              commands that normally shouldn't be called from Lisp code."
  :group 'bytecomp
  :type `(choice (const :tag "All" t)
                 (set :menu-tag "Some"
                      (const free-vars) (const unresolved)
                      (const callargs) (const redefine)
                      (const obsolete) (const noruntime)
                      (const cl-functions) (const interactive-only))))
;;;###autoload(put 'byte-compile-warnings 'safe-local-variable 'byte-compile-warnings-safe-p)

;;;###autoload
(defun byte-compile-warnings-safe-p (x)
  (or (booleanp x)
      (and (listp x)
           (equal (mapcar
                   (lambda (e)
                     (when (memq e '(free-vars unresolved
                                     callargs redefine
                                     obsolete noruntime
                                     cl-functions interactive-only))
                       e))
                   x)
                  x))))

(defvar byte-compile-interactive-only-functions
  '(beginning-of-buffer end-of-buffer replace-string replace-regexp
    insert-file insert-buffer insert-file-literally)
  "List of commands that are not meant to be called from Lisp.")

(defvar byte-compile-not-obsolete-var nil
  "If non-nil, this is a variable that shouldn't be reported as obsolete.")

(defcustom byte-compile-generate-call-tree nil
  "*Non-nil means collect call-graph information when compiling.
This records which functions were called and from where.
If the value is t, compilation displays the call graph when it finishes.
If the value is neither t nor nil, compilation asks you whether to display
the graph.

The call tree only lists functions called, not macros used. Those functions
which the byte-code interpreter knows about directly (eq, cons, etc.) are
not reported.

The call tree also lists those functions which are not known to be called
\(that is, to which no calls have been compiled).  Functions which can be
invoked interactively are excluded from this list."
  :group 'bytecomp
  :type '(choice (const :tag "Yes" t) (const :tag "No" nil)
                 (other :tag "Ask" lambda)))

(defvar byte-compile-call-tree nil "Alist of functions and their call tree.
Each element looks like

  \(FUNCTION CALLERS CALLS\)

where CALLERS is a list of functions that call FUNCTION, and CALLS
is a list of functions for which calls were generated while compiling
FUNCTION.")

(defcustom byte-compile-call-tree-sort 'name
  "*If non-nil, sort the call tree.
The values `name', `callers', `calls', `calls+callers'
specify different fields to sort on."
  :group 'bytecomp
  :type '(choice (const name) (const callers) (const calls)
                 (const calls+callers) (const nil)))

(defvar byte-compile-debug nil)

;; (defvar byte-compile-overwrite-file t
;;   "If nil, old .elc files are deleted before the new is saved, and .elc
;; files will have the same modes as the corresponding .el file.  Otherwise,
;; existing .elc files will simply be overwritten, and the existing modes
;; will not be changed.  If this variable is nil, then an .elc file which
;; is a symbolic link will be turned into a normal file, instead of the file
;; which the link points to being overwritten.")

(defvar byte-compile-constants nil
  "List of all constants encountered during compilation of this form.")
(defvar byte-compile-variables nil
  "List of all variables encountered during compilation of this form.")
(defvar byte-compile-bound-variables nil
  "List of variables bound in the context of the current form.
This list lives partly on the stack.")
(defvar byte-compile-const-variables nil
  "List of variables declared as constants during compilation of this file.")
(defvar byte-compile-free-references)
(defvar byte-compile-free-assignments)

(defvar byte-compiler-error-flag)

(defconst byte-compile-initial-macro-environment
  '(
;;     (byte-compiler-options . (lambda (&rest forms)
;;                             (apply 'byte-compiler-options-handler forms)))
    (eval-when-compile . (lambda (&rest body)
                           (list 'quote
                                 (byte-compile-eval (byte-compile-top-level
                                                     (cons 'progn body))))))
    (eval-and-compile . (lambda (&rest body)
                          (byte-compile-eval-before-compile (cons 'progn body))
                          (cons 'progn body))))
  "The default macro-environment passed to macroexpand by the compiler.
Placing a macro here will cause a macro to have different semantics when
expanded by the compiler as when expanded by the interpreter.")

(defvar byte-compile-macro-environment byte-compile-initial-macro-environment
  "Alist of macros defined in the file being compiled.
Each element looks like (MACRONAME . DEFINITION).  It is
\(MACRONAME . nil) when a macro is redefined as a function.")

(defvar byte-compile-function-environment nil
  "Alist of functions defined in the file being compiled.
This is so we can inline them when necessary.
Each element looks like (FUNCTIONNAME . DEFINITION).  It is
\(FUNCTIONNAME . nil) when a function is redefined as a macro.
It is \(FUNCTIONNAME . t) when all we know is that it was defined,
and we don't know the definition.")

(defvar byte-compile-unresolved-functions nil
  "Alist of undefined functions to which calls have been compiled.
This variable is only significant whilst compiling an entire buffer.
Used for warnings when a function is not known to be defined or is later
defined with incorrect args.")

(defvar byte-compile-noruntime-functions nil
  "Alist of functions called that may not be defined when the compiled code is run.
Used for warnings about calling a function that is defined during compilation
but won't necessarily be defined when the compiled file is loaded.")

(defvar byte-compile-tag-number 0)
(defvar byte-compile-output nil
  "Alist describing contents to put in byte code string.
Each element is (INDEX . VALUE)")
(defvar byte-compile-depth 0 "Current depth of execution stack.")
(defvar byte-compile-maxdepth 0 "Maximum depth of execution stack.")


;;; The byte codes; this information is duplicated in bytecomp.c

(defvar byte-code-vector nil
  "An array containing byte-code names indexed by byte-code values.")

(defvar byte-stack+-info nil
  "An array with the stack adjustment for each byte-code.")

(defmacro byte-defop (opcode stack-adjust opname &optional docstring)
  ;; This is a speed-hack for building the byte-code-vector at compile-time.
  ;; We fill in the vector at macroexpand-time, and then after the last call
  ;; to byte-defop, we write the vector out as a constant instead of writing
  ;; out a bunch of calls to aset.
  ;; Actually, we don't fill in the vector itself, because that could make
  ;; it problematic to compile big changes to this compiler; we store the
  ;; values on its plist, and remove them later in -extrude.
  (let ((v1 (or (get 'byte-code-vector 'tmp-compile-time-value)
                (put 'byte-code-vector 'tmp-compile-time-value
                     (make-vector 256 nil))))
        (v2 (or (get 'byte-stack+-info 'tmp-compile-time-value)
                (put 'byte-stack+-info 'tmp-compile-time-value
                     (make-vector 256 nil)))))
    (aset v1 opcode opname)
    (aset v2 opcode stack-adjust))
  (if docstring
      (list 'defconst opname opcode (concat "Byte code opcode " docstring "."))
      (list 'defconst opname opcode)))

(defmacro byte-extrude-byte-code-vectors ()
  (prog1 (list 'setq 'byte-code-vector
                     (get 'byte-code-vector 'tmp-compile-time-value)
                     'byte-stack+-info
                     (get 'byte-stack+-info 'tmp-compile-time-value))
    (put 'byte-code-vector 'tmp-compile-time-value nil)
    (put 'byte-stack+-info 'tmp-compile-time-value nil)))


;; unused: 0-7

;; These opcodes are special in that they pack their argument into the
;; opcode word.
;;
(byte-defop   8  1 byte-varref  "for variable reference")
(byte-defop  16 -1 byte-varset  "for setting a variable")
(byte-defop  24 -1 byte-varbind "for binding a variable")
(byte-defop  32  0 byte-call    "for calling a function")
(byte-defop  40  0 byte-unbind  "for unbinding special bindings")
;; codes 8-47 are consumed by the preceding opcodes

;; unused: 48-55

(byte-defop  56 -1 byte-nth)
(byte-defop  57  0 byte-symbolp)
(byte-defop  58  0 byte-consp)
(byte-defop  59  0 byte-stringp)
(byte-defop  60  0 byte-listp)
(byte-defop  61 -1 byte-eq)
(byte-defop  62 -1 byte-memq)
(byte-defop  63  0 byte-not)
(byte-defop  64  0 byte-car)
(byte-defop  65  0 byte-cdr)
(byte-defop  66 -1 byte-cons)
(byte-defop  67  0 byte-list1)
(byte-defop  68 -1 byte-list2)
(byte-defop  69 -2 byte-list3)
(byte-defop  70 -3 byte-list4)
(byte-defop  71  0 byte-length)
(byte-defop  72 -1 byte-aref)
(byte-defop  73 -2 byte-aset)
(byte-defop  74  0 byte-symbol-value)
(byte-defop  75  0 byte-symbol-function) ; this was commented out
(byte-defop  76 -1 byte-set)
(byte-defop  77 -1 byte-fset) ; this was commented out
(byte-defop  78 -1 byte-get)
(byte-defop  79 -2 byte-substring)
(byte-defop  80 -1 byte-concat2)
(byte-defop  81 -2 byte-concat3)
(byte-defop  82 -3 byte-concat4)
(byte-defop  83  0 byte-sub1)
(byte-defop  84  0 byte-add1)
(byte-defop  85 -1 byte-eqlsign)
(byte-defop  86 -1 byte-gtr)
(byte-defop  87 -1 byte-lss)
(byte-defop  88 -1 byte-leq)
(byte-defop  89 -1 byte-geq)
(byte-defop  90 -1 byte-diff)
(byte-defop  91  0 byte-negate)
(byte-defop  92 -1 byte-plus)
(byte-defop  93 -1 byte-max)
(byte-defop  94 -1 byte-min)
(byte-defop  95 -1 byte-mult) ; v19 only
(byte-defop  96  1 byte-point)
(byte-defop  98  0 byte-goto-char)
(byte-defop  99  0 byte-insert)
(byte-defop 100  1 byte-point-max)
(byte-defop 101  1 byte-point-min)
(byte-defop 102  0 byte-char-after)
(byte-defop 103  1 byte-following-char)
(byte-defop 104  1 byte-preceding-char)
(byte-defop 105  1 byte-current-column)
(byte-defop 106  0 byte-indent-to)
(byte-defop 107  0 byte-scan-buffer-OBSOLETE) ; no longer generated as of v18
(byte-defop 108  1 byte-eolp)
(byte-defop 109  1 byte-eobp)
(byte-defop 110  1 byte-bolp)
(byte-defop 111  1 byte-bobp)
(byte-defop 112  1 byte-current-buffer)
(byte-defop 113  0 byte-set-buffer)
(byte-defop 114  0 byte-save-current-buffer
  "To make a binding to record the current buffer")
(byte-defop 115  0 byte-set-mark-OBSOLETE)
(byte-defop 116  1 byte-interactive-p)

;; These ops are new to v19
(byte-defop 117  0 byte-forward-char)
(byte-defop 118  0 byte-forward-word)
(byte-defop 119 -1 byte-skip-chars-forward)
(byte-defop 120 -1 byte-skip-chars-backward)
(byte-defop 121  0 byte-forward-line)
(byte-defop 122  0 byte-char-syntax)
(byte-defop 123 -1 byte-buffer-substring)
(byte-defop 124 -1 byte-delete-region)
(byte-defop 125 -1 byte-narrow-to-region)
(byte-defop 126  1 byte-widen)
(byte-defop 127  0 byte-end-of-line)

;; unused: 128

;; These store their argument in the next two bytes
(byte-defop 129  1 byte-constant2
   "for reference to a constant with vector index >= byte-constant-limit")
(byte-defop 130  0 byte-goto "for unconditional jump")
(byte-defop 131 -1 byte-goto-if-nil "to pop value and jump if it's nil")
(byte-defop 132 -1 byte-goto-if-not-nil "to pop value and jump if it's not nil")
(byte-defop 133 -1 byte-goto-if-nil-else-pop
  "to examine top-of-stack, jump and don't pop it if it's nil,
otherwise pop it")
(byte-defop 134 -1 byte-goto-if-not-nil-else-pop
  "to examine top-of-stack, jump and don't pop it if it's non nil,
otherwise pop it")

(byte-defop 135 -1 byte-return "to pop a value and return it from `byte-code'")
(byte-defop 136 -1 byte-discard "to discard one value from stack")
(byte-defop 137  1 byte-dup     "to duplicate the top of the stack")

(byte-defop 138  0 byte-save-excursion
  "to make a binding to record the buffer, point and mark")
(byte-defop 139  0 byte-save-window-excursion
  "to make a binding to record entire window configuration")
(byte-defop 140  0 byte-save-restriction
  "to make a binding to record the current buffer clipping restrictions")
(byte-defop 141 -1 byte-catch
  "for catch.  Takes, on stack, the tag and an expression for the body")
(byte-defop 142 -1 byte-unwind-protect
  "for unwind-protect.  Takes, on stack, an expression for the unwind-action")

;; For condition-case.  Takes, on stack, the variable to bind,
;; an expression for the body, and a list of clauses.
(byte-defop 143 -2 byte-condition-case)

;; For entry to with-output-to-temp-buffer.
;; Takes, on stack, the buffer name.
;; Binds standard-output and does some other things.
;; Returns with temp buffer on the stack in place of buffer name.
(byte-defop 144  0 byte-temp-output-buffer-setup)

;; For exit from with-output-to-temp-buffer.
;; Expects the temp buffer on the stack underneath value to return.
;; Pops them both, then pushes the value back on.
;; Unbinds standard-output and makes the temp buffer visible.
(byte-defop 145 -1 byte-temp-output-buffer-show)

;; these ops are new to v19

;; To unbind back to the beginning of this frame.
;; Not used yet, but will be needed for tail-recursion elimination.
(byte-defop 146  0 byte-unbind-all)

;; these ops are new to v19
(byte-defop 147 -2 byte-set-marker)
(byte-defop 148  0 byte-match-beginning)
(byte-defop 149  0 byte-match-end)
(byte-defop 150  0 byte-upcase)
(byte-defop 151  0 byte-downcase)
(byte-defop 152 -1 byte-string=)
(byte-defop 153 -1 byte-string<)
(byte-defop 154 -1 byte-equal)
(byte-defop 155 -1 byte-nthcdr)
(byte-defop 156 -1 byte-elt)
(byte-defop 157 -1 byte-member)
(byte-defop 158 -1 byte-assq)
(byte-defop 159  0 byte-nreverse)
(byte-defop 160 -1 byte-setcar)
(byte-defop 161 -1 byte-setcdr)
(byte-defop 162  0 byte-car-safe)
(byte-defop 163  0 byte-cdr-safe)
(byte-defop 164 -1 byte-nconc)
(byte-defop 165 -1 byte-quo)
(byte-defop 166 -1 byte-rem)
(byte-defop 167  0 byte-numberp)
(byte-defop 168  0 byte-integerp)

;; unused: 169-174
(byte-defop 175 nil byte-listN)
(byte-defop 176 nil byte-concatN)
(byte-defop 177 nil byte-insertN)

;; unused: 178-191

(byte-defop 192  1 byte-constant        "for reference to a constant")
;; codes 193-255 are consumed by byte-constant.
(defconst byte-constant-limit 64
  "Exclusive maximum index usable in the `byte-constant' opcode.")

(defconst byte-goto-ops '(byte-goto byte-goto-if-nil byte-goto-if-not-nil
                          byte-goto-if-nil-else-pop
                          byte-goto-if-not-nil-else-pop)
  "List of byte-codes whose offset is a pc.")

(defconst byte-goto-always-pop-ops '(byte-goto-if-nil byte-goto-if-not-nil))

(byte-extrude-byte-code-vectors)

;;; lapcode generator
;;
;; the byte-compiler now does source -> lapcode -> bytecode instead of
;; source -> bytecode, because it's a lot easier to make optimizations
;; on lapcode than on bytecode.
;;
;; Elements of the lapcode list are of the form (<instruction> . <parameter>)
;; where instruction is a symbol naming a byte-code instruction,
;; and parameter is an argument to that instruction, if any.
;;
;; The instruction can be the pseudo-op TAG, which means that this position
;; in the instruction stream is a target of a goto.  (car PARAMETER) will be
;; the PC for this location, and the whole instruction "(TAG pc)" will be the
;; parameter for some goto op.
;;
;; If the operation is varbind, varref, varset or push-constant, then the
;; parameter is (variable/constant . index_in_constant_vector).
;;
;; First, the source code is macroexpanded and optimized in various ways.
;; Then the resultant code is compiled into lapcode.  Another set of
;; optimizations are then run over the lapcode.  Then the variables and
;; constants referenced by the lapcode are collected and placed in the
;; constants-vector.  (This happens now so that variables referenced by dead
;; code don't consume space.)  And finally, the lapcode is transformed into
;; compacted byte-code.
;;
;; A distinction is made between variables and constants because the variable-
;; referencing instructions are more sensitive to the variables being near the
;; front of the constants-vector than the constant-referencing instructions.
;; Also, this lets us notice references to free variables.

(defun byte-compile-lapcode (lap)
  "Turns lapcode into bytecode.  The lapcode is destroyed."
  ;; Lapcode modifications: changes the ID of a tag to be the tag's PC.
  (let ((pc 0)                  ; Program counter
        op off                  ; Operation & offset
        (bytes '())             ; Put the output bytes here
        (patchlist nil))        ; List of tags and goto's to patch
    (while lap
      (setq op (car (car lap))
            off (cdr (car lap)))
      (cond ((not (symbolp op))
             (error "Non-symbolic opcode `%s'" op))
            ((eq op 'TAG)
             (setcar off pc)
             (setq patchlist (cons off patchlist)))
            ((memq op byte-goto-ops)
             (setq pc (+ pc 3))
             (setq bytes (cons (cons pc (cdr off))
                               (cons nil
                                     (cons (symbol-value op) bytes))))
             (setq patchlist (cons bytes patchlist)))
            (t
             (setq bytes
                   (cond ((cond ((consp off)
                                 ;; Variable or constant reference