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authorPaul Eggert <eggert@cs.ucla.edu>2018-08-21 13:44:03 -0700
committerPaul Eggert <eggert@cs.ucla.edu>2018-08-21 13:44:32 -0700
commitf18af6cd5cb7dbbf7420ec2d3efed4e202c4f0dd (patch)
tree5f42e48e12a0ec77bd5cd5f32255a534635e89bf /lisp/emacs-lisp/bytecomp.el
parent81e7eef8224c8a99a207b7a7b9dae1d598392ef7 (diff)
downloademacs-f18af6cd5cb7dbbf7420ec2d3efed4e202c4f0dd.tar.gz
Audit use of lsh and fix glitches
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.
Diffstat (limited to 'lisp/emacs-lisp/bytecomp.el')
-rw-r--r--lisp/emacs-lisp/bytecomp.el12
1 files changed, 6 insertions, 6 deletions
diff --git a/lisp/emacs-lisp/bytecomp.el b/lisp/emacs-lisp/bytecomp.el
index ee28e61800d..0b8f8824b4c 100644
--- a/lisp/emacs-lisp/bytecomp.el
+++ b/lisp/emacs-lisp/bytecomp.el
@@ -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 ())