From f18af6cd5cb7dbbf7420ec2d3efed4e202c4f0dd Mon Sep 17 00:00:00 2001 From: Paul Eggert Date: Tue, 21 Aug 2018 13:44:03 -0700 Subject: 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. --- lisp/emacs-lisp/bytecomp.el | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) (limited to 'lisp/emacs-lisp/bytecomp.el') 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 ()) -- cgit v1.2.1