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Audit use of lsh and fix glitches

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I audited use of lsh in the Lisp source code, and fixed the
glitches that I found.  While I was at it, I replaced uses of lsh
with ash when either will do.  Replacement is OK when either
argument is known to be nonnegative, or when only the low-order
bits of the result matter, and is a (minor) win since ash is a bit
more solid than lsh nowadays, and is a bit faster.
* lisp/calc/calc-ext.el (math-check-fixnum):
Prefer most-positive-fixnum to (lsh -1 -1).
* lisp/vc/vc-hg.el (vc-hg-state-fast): When testing fixnum width,
prefer (zerop (ash most-positive-fixnum -32)) to (zerop (lsh -1
32)) (Bug#32485#11).
* lisp/emacs-lisp/bytecomp.el (byte-compile-lapcode):
Tighten sanity-check for bytecode overflow, by checking that the
result of (ash pc -8) is nonnegative.  Formerly this check was not
needed since lsh was used and the number overflowed differently.
* lisp/net/dns.el (dns-write): Fix some obvious sign typos in
shift counts.  Evidently this part of the code has never been
exercised.
* lisp/progmodes/hideif.el (hif-shiftleft, hif-shiftright):
* lisp/term/common-win.el (x-setup-function-keys):
Simplify.
* admin/unidata/unidata-gen.el, admin/unidata/uvs.el:
* doc/lispref/keymaps.texi, doc/lispref/syntax.texi:
* doc/misc/calc.texi, doc/misc/cl.texi, etc/NEWS.19:
* lisp/arc-mode.el, lisp/calc/calc-bin.el, lisp/calc/calc-comb.el:
* lisp/calc/calc-ext.el, lisp/calc/calc-math.el:
* lisp/cedet/semantic/wisent/comp.el, lisp/composite.el:
* lisp/disp-table.el, lisp/dos-fns.el, lisp/edmacro.el:
* lisp/emacs-lisp/bindat.el, lisp/emacs-lisp/byte-opt.el:
* lisp/emacs-lisp/bytecomp.el, lisp/emacs-lisp/cl-extra.el:
* lisp/erc/erc-dcc.el, lisp/facemenu.el, lisp/gnus/message.el:
* lisp/gnus/nndoc.el, lisp/gnus/nnmaildir.el, lisp/image.el:
* lisp/international/ccl.el, lisp/international/fontset.el:
* lisp/international/mule-cmds.el, lisp/international/mule.el:
* lisp/json.el, lisp/mail/binhex.el, lisp/mail/rmail.el:
* lisp/mail/uudecode.el, lisp/md4.el, lisp/net/dns.el:
* lisp/net/ntlm.el, lisp/net/sasl.el, lisp/net/socks.el:
* lisp/net/tramp.el, lisp/obsolete/levents.el:
* lisp/obsolete/pgg-parse.el, lisp/org/org.el:
* lisp/org/ox-publish.el, lisp/progmodes/cc-defs.el:
* lisp/progmodes/ebnf2ps.el, lisp/progmodes/hideif.el:
* lisp/ps-bdf.el, lisp/ps-print.el, lisp/simple.el:
* lisp/tar-mode.el, lisp/term/common-win.el:
* lisp/term/tty-colors.el, lisp/term/xterm.el, lisp/vc/vc-git.el:
* lisp/vc/vc-hg.el, lisp/x-dnd.el, test/src/data-tests.el:
Prefer ash to lsh when either will do.
This commit is contained in:
Paul Eggert 2018-08-21 13:44:03 -07:00
parent 81e7eef822
commit f18af6cd5c
59 changed files with 235 additions and 239 deletions
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12
lisp/emacs-lisp/bytecomp.el
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@ -835,7 +835,7 @@ all the arguments.
(defmacro byte-compile-push-bytecode-const2 (opcode const2 bytes pc)
"Push OPCODE and the two-byte constant CONST2 onto BYTES, and add 3 to PC.
CONST2 may be evaluated multiple times."
`(byte-compile-push-bytecodes ,opcode (logand ,const2 255) (lsh ,const2 -8)
`(byte-compile-push-bytecodes ,opcode (logand ,const2 255) (ash ,const2 -8)
,bytes ,pc))
(defun byte-compile-lapcode (lap)
@ -925,9 +925,9 @@ CONST2 may be evaluated multiple times."
;; Splits PC's value into 2 bytes. The jump address is
;; "reconstructed" by the `FETCH2' macro in `bytecode.c'.
(setcar (cdr bytes-tail) (logand pc 255))
(setcar bytes-tail (lsh pc -8))
(setcar bytes-tail (ash pc -8))
;; FIXME: Replace this by some workaround.
(if (> (car bytes-tail) 255) (error "Bytecode overflow")))
(or (<= 0 (car bytes-tail) 255) (error "Bytecode overflow")))
;; Similarly, replace TAGs in all jump tables with the correct PC index.
(dolist (hash-table byte-compile-jump-tables)
@ -2793,8 +2793,8 @@ If FORM is a lambda or a macro, byte-compile it as a function."
(if (> mandatory 127)
(byte-compile-report-error "Too many (>127) mandatory arguments")
(logior mandatory
(lsh nonrest 8)
(lsh rest 7)))))
(ash nonrest 8)
(ash rest 7)))))
(defun byte-compile-lambda (fun &optional add-lambda reserved-csts)
@ -3258,7 +3258,7 @@ for symbols generated by the byte compiler itself."
(fun (car form))
(fargs (aref fun 0))
(start-depth byte-compile-depth)
(fmax2 (if (numberp fargs) (lsh fargs -7))) ;2*max+rest.
(fmax2 (if (numberp fargs) (ash fargs -7))) ;2*max+rest.
;; (fmin (if (numberp fargs) (logand fargs 127)))
(alen (length (cdr form)))
(dynbinds ())