Package: emacs;
Reported by: Eli Zaretskii <eliz <at> gnu.org>
Date: Sun, 1 Mar 2020 17:21:02 UTC
Severity: minor
Found in version 27.0.90
Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):
From: Eli Zaretskii <eliz <at> gnu.org> To: bug-gnu-emacs <at> gnu.org Subject: 27.0.90; Compilation warning about alloca in 32-bit MinGW build Date: Sun, 01 Mar 2020 19:20:31 +0200
Building a 32-bit Emacs 27.0.90 with MinGW GCC 8.2 and -Og
optimization produces the following compilation warning:
CC edittfns.o
In file included from lisp.h:24,
from editfns.c:36:
editfns.c: In function 'styled_format':
../lib/alloca.h:46:18: warning: argument 1 range [2147483648, 4294961362] exceeds maximum object size 2147483647 [-Walloc-size-larger-than=]
# define alloca __builtin_alloca
lisp.h:4810:49: note: in expansion of macro 'alloca'
#define AVAIL_ALLOCA(size) (sa_avail -= (size), alloca (size))
^~~~~~
lisp.h:4815:9: note: in expansion of macro 'AVAIL_ALLOCA'
? AVAIL_ALLOCA (size) \
^~~~~~~~~~~~
editfns.c:3167:10: note: in expansion of macro 'SAFE_ALLOCA'
info = SAFE_ALLOCA (alloca_size);
^~~~~~~~~~~
../lib/alloca.h:46:18: note: in a call to built-in allocation function '__builtin_alloca'
# define alloca __builtin_alloca
lisp.h:4810:49: note: in expansion of macro 'alloca'
#define AVAIL_ALLOCA(size) (sa_avail -= (size), alloca (size))
^~~~~~
lisp.h:4815:9: note: in expansion of macro 'AVAIL_ALLOCA'
? AVAIL_ALLOCA (size) \
^~~~~~~~~~~~
editfns.c:3167:10: note: in expansion of macro 'SAFE_ALLOCA'
info = SAFE_ALLOCA (alloca_size);
^~~~~~~~~~~
The GCC manual says about -Walloc-size-larger-than=N:
'-Walloc-size-larger-than=N'
Warn about calls to functions decorated with attribute 'alloc_size'
that attempt to allocate objects larger than the specified number
of bytes, or where the result of the size computation in an integer
type with infinite precision would exceed 'SIZE_MAX / 2'. The
option argument N may end in one of the standard suffixes
designating a multiple of bytes such as 'kB' and 'KiB' for kilobyte
and kibibyte, respectively, 'MB' and 'MiB' for megabyte and
mebibyte, and so on. '-Walloc-size-larger-than='PTRDIFF_MAX is
enabled by default. Warnings controlled by the option can be
disabled by specifying N of SIZE_MAX or more. *Note Function
Attributes::.
I guess __builtin_alloca is "decorated with alloc_size" attribute, and
thus the warning. Of course large memory allocations never end up in
alloca, we call malloc instead. Which probably means GCC is not smart
enough to understand SAFE_ALLOCA?
WIBNI this annoying warning could be shut up?
TIA.
In GNU Emacs 27.0.90 (build 1, i686-pc-mingw32)
of 2020-03-01 built on HOME-C4E4A596F7
Windowing system distributor 'Microsoft Corp.', version 5.1.2600
System Description: Microsoft Windows XP Service Pack 3 (v5.1.0.2600)
Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.
Configured using:
'configure -C --prefix=/d/usr --with-wide-int --with-modules
'CFLAGS=-Og -gdwarf-4 -g3''
Configured features:
XPM JPEG TIFF GIF PNG RSVG SOUND NOTIFY W32NOTIFY ACL GNUTLS LIBXML2
HARFBUZZ ZLIB TOOLKIT_SCROLL_BARS MODULES THREADS JSON PDUMPER LCMS2 GMP
Important settings:
value of $LANG: ENU
locale-coding-system: cp1255
Major mode: Lisp Interaction
Minor modes in effect:
tooltip-mode: t
global-eldoc-mode: t
eldoc-mode: t
electric-indent-mode: t
mouse-wheel-mode: t
tool-bar-mode: t
menu-bar-mode: t
file-name-shadow-mode: t
global-font-lock-mode: t
font-lock-mode: t
blink-cursor-mode: t
auto-composition-mode: t
auto-encryption-mode: t
auto-compression-mode: t
line-number-mode: t
transient-mark-mode: t
Load-path shadows:
None found.
Features:
(shadow sort mail-extr emacsbug message rmc puny dired dired-loaddefs
format-spec rfc822 mml easymenu mml-sec password-cache epa derived epg
epg-config gnus-util rmail rmail-loaddefs text-property-search time-date
subr-x seq byte-opt gv bytecomp byte-compile cconv mm-decode mm-bodies
mm-encode mail-parse rfc2231 mailabbrev gmm-utils mailheader cl-loaddefs
cl-lib sendmail rfc2047 rfc2045 ietf-drums mm-util mail-prsvr mail-utils
tooltip eldoc electric uniquify ediff-hook vc-hooks lisp-float-type
mwheel dos-w32 ls-lisp disp-table term/w32-win w32-win w32-vars
term/common-win tool-bar dnd fontset image regexp-opt fringe
tabulated-list replace newcomment text-mode elisp-mode lisp-mode
prog-mode register page tab-bar menu-bar rfn-eshadow isearch timer
select scroll-bar mouse jit-lock font-lock syntax facemenu font-core
term/tty-colors frame minibuffer cl-generic cham georgian utf-8-lang
misc-lang vietnamese tibetan thai tai-viet lao korean japanese eucjp-ms
cp51932 hebrew greek romanian slovak czech european ethiopic indian
cyrillic chinese composite charscript charprop case-table epa-hook
jka-cmpr-hook help simple abbrev obarray cl-preloaded nadvice loaddefs
button faces cus-face macroexp files text-properties overlay sha1 md5
base64 format env code-pages mule custom widget hashtable-print-readable
backquote threads w32notify w32 lcms2 multi-tty make-network-process
emacs)
Memory information:
((conses 16 51245 8998)
(symbols 48 7171 1)
(strings 16 18830 2275)
(string-bytes 1 532711)
(vectors 16 10213)
(vector-slots 8 131934 8682)
(floats 8 21 109)
(intervals 40 252 92)
(buffers 888 11))
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