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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
Download patch file Download diff file Expand all files Collapse all files

28
lisp/emacs-lisp/bindat.el
View file

@ -205,22 +205,22 @@
(setq bindat-idx (1+ bindat-idx))))
(defun bindat--unpack-u16 ()
(logior (lsh (bindat--unpack-u8) 8) (bindat--unpack-u8)))
(logior (ash (bindat--unpack-u8) 8) (bindat--unpack-u8)))
(defun bindat--unpack-u24 ()
(logior (lsh (bindat--unpack-u16) 8) (bindat--unpack-u8)))
(logior (ash (bindat--unpack-u16) 8) (bindat--unpack-u8)))
(defun bindat--unpack-u32 ()
(logior (lsh (bindat--unpack-u16) 16) (bindat--unpack-u16)))
(logior (ash (bindat--unpack-u16) 16) (bindat--unpack-u16)))
(defun bindat--unpack-u16r ()
(logior (bindat--unpack-u8) (lsh (bindat--unpack-u8) 8)))
(logior (bindat--unpack-u8) (ash (bindat--unpack-u8) 8)))
(defun bindat--unpack-u24r ()
(logior (bindat--unpack-u16r) (lsh (bindat--unpack-u8) 16)))
(logior (bindat--unpack-u16r) (ash (bindat--unpack-u8) 16)))
(defun bindat--unpack-u32r ()
(logior (bindat--unpack-u16r) (lsh (bindat--unpack-u16r) 16)))
(logior (bindat--unpack-u16r) (ash (bindat--unpack-u16r) 16)))
(defun bindat--unpack-item (type len &optional vectype)
(if (eq type 'ip)
@ -250,7 +250,7 @@
(if (/= 0 (logand m j))
(setq bits (cons bnum bits)))
(setq bnum (1- bnum)
j (lsh j -1)))))
j (ash j -1)))))
bits))
((eq type 'str)
(let ((s (substring bindat-raw bindat-idx (+ bindat-idx len))))
@ -459,30 +459,30 @@ e.g. corresponding to STRUCT.FIELD1[INDEX2].FIELD3..."
(setq bindat-idx (1+ bindat-idx)))
(defun bindat--pack-u16 (v)
(aset bindat-raw bindat-idx (logand (lsh v -8) 255))
(aset bindat-raw bindat-idx (logand (ash v -8) 255))
(aset bindat-raw (1+ bindat-idx) (logand v 255))
(setq bindat-idx (+ bindat-idx 2)))
(defun bindat--pack-u24 (v)
(bindat--pack-u8 (lsh v -16))
(bindat--pack-u8 (ash v -16))
(bindat--pack-u16 v))
(defun bindat--pack-u32 (v)
(bindat--pack-u16 (lsh v -16))
(bindat--pack-u16 (ash v -16))
(bindat--pack-u16 v))
(defun bindat--pack-u16r (v)
(aset bindat-raw (1+ bindat-idx) (logand (lsh v -8) 255))
(aset bindat-raw (1+ bindat-idx) (logand (ash v -8) 255))
(aset bindat-raw bindat-idx (logand v 255))
(setq bindat-idx (+ bindat-idx 2)))
(defun bindat--pack-u24r (v)
(bindat--pack-u16r v)
(bindat--pack-u8 (lsh v -16)))
(bindat--pack-u8 (ash v -16)))
(defun bindat--pack-u32r (v)
(bindat--pack-u16r v)
(bindat--pack-u16r (lsh v -16)))
(bindat--pack-u16r (ash v -16)))
(defun bindat--pack-item (v type len &optional vectype)
(if (eq type 'ip)
@ -515,7 +515,7 @@ e.g. corresponding to STRUCT.FIELD1[INDEX2].FIELD3..."
(if (memq bnum v)
(setq m (logior m j)))
(setq bnum (1- bnum)
j (lsh j -1))))
j (ash j -1))))
(bindat--pack-u8 m))))
((memq type '(str strz))
(let ((l (length v)) (i 0))

4
lisp/emacs-lisp/byte-opt.el
View file

@ -1283,7 +1283,7 @@
(setq bytedecomp-ptr (1+ bytedecomp-ptr))
(+ (aref bytes bytedecomp-ptr)
(progn (setq bytedecomp-ptr (1+ bytedecomp-ptr))
(lsh (aref bytes bytedecomp-ptr) 8))))
(ash (aref bytes bytedecomp-ptr) 8))))
(t tem)))) ;Offset was in opcode.
((>= bytedecomp-op byte-constant)
(prog1 (- bytedecomp-op byte-constant) ;Offset in opcode.
@ -1297,7 +1297,7 @@
(setq bytedecomp-ptr (1+ bytedecomp-ptr))
(+ (aref bytes bytedecomp-ptr)
(progn (setq bytedecomp-ptr (1+ bytedecomp-ptr))
(lsh (aref bytes bytedecomp-ptr) 8))))
(ash (aref bytes bytedecomp-ptr) 8))))
((and (>= bytedecomp-op byte-listN)
(<= bytedecomp-op byte-discardN))
(setq bytedecomp-ptr (1+ bytedecomp-ptr)) ;Offset in next byte.

12
lisp/emacs-lisp/bytecomp.el
View file

@ -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 ())

2
lisp/emacs-lisp/cl-extra.el
View file

@ -472,7 +472,7 @@ Optional second arg STATE is a random-state object."
(n (logand 8388607 (aset vec i (- (aref vec i) (aref vec j))))))
(if (integerp lim)
(if (<= lim 512) (% n lim)
(if (> lim 8388607) (setq n (+ (lsh n 9) (cl-random 512 state))))
(if (> lim 8388607) (setq n (+ (ash n 9) (cl-random 512 state))))
(let ((mask 1023))
(while (< mask (1- lim)) (setq mask (1+ (+ mask mask))))
(if (< (setq n (logand n mask)) lim) n (cl-random lim state))))