61aa40aeb3
When compiling with link time optimization, GCC thinks it's discovered undefined behavior: events.c: In function 'XineramaConfineCursorToWindow': events.c:609:13: warning: iteration 2147483647 invokes undefined behavior [-Waggressive-loop-optimizations] events.c:609:11: note: within this loop events.c:605:49: warning: array subscript -1 is below array bounds of 'struct _Window *[16]' [-Warray-bounds] events.c:606:31: warning: array subscript -1 is below array bounds of 'struct _Screen *[16]' [-Warray-bounds] events.c:610:39: warning: array subscript -2 is below array bounds of 'struct _Screen *[16]' [-Warray-bounds] events.c:617:38: warning: array subscript -2 is below array bounds of 'struct _Window *[16]' [-Warray-bounds] events.c:619:35: warning: array subscript -2 is below array bounds of 'struct _Screen *[16]' [-Warray-bounds] This results from i = PanoramiXNumScreens - 1; RegionCopy(&pSprite->Reg1, &pSprite->windows[i]->borderSize); off_x = screenInfo.screens[i]->x; off_y = screenInfo.screens[i]->y; where GCC believes that PanoramiXNumScreens might be 0. Unfortunately GCC is just smart enough to be an annoyance because this case is not actually possible: XineramaConfineCursorToWindow() is only called when noPanoramiXExtension is false, and if noPanoramiXExtension is false then PanoramiXNumScreens must be >1 (see PanoramiXExtensionInit()). So, add an assert(!noPanoramiXExtension), which to my surprise provides GCC with information even in release builds and lets GCC understand that the code is not doing anything that is undefined behavior. I chose this solution instead of the proposed assert(i >= 0) because the same pattern occurs in CheckVirtualMotion() but is inside an 'if (!noPanoramiXExtension)' and does not generate any warnings. Fixes: xorg/xserver#590 Signed-off-by: Matt Turner <mattst88@gmail.com> |
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composite | ||
config | ||
damageext | ||
dbe | ||
dix | ||
doc | ||
dri3 | ||
exa | ||
fb | ||
glamor | ||
glx | ||
hw | ||
include | ||
m4 | ||
man | ||
mi | ||
miext | ||
os | ||
present | ||
pseudoramiX | ||
randr | ||
record | ||
render | ||
test | ||
Xext | ||
xfixes | ||
Xi | ||
xkb | ||
.appveyor.yml | ||
.dir-locals.el | ||
.gitignore | ||
.gitlab-ci.yml | ||
.travis.yml | ||
autogen.sh | ||
buildDateTime.h.in | ||
buildDateTime.sh | ||
configure.ac | ||
COPYING | ||
devbook.am | ||
docbook.am | ||
Makefile.am | ||
manpages.am | ||
meson_options.txt | ||
meson.build | ||
README.md | ||
xorg-server.m4 | ||
xorg-server.pc.in | ||
xserver.ent.in |
X Server
The X server accepts requests from client applications to create windows, which are (normally rectangular) "virtual screens" that the client program can draw into.
Windows are then composed on the actual screen by the X server (or by a separate composite manager) as directed by the window manager, which usually communicates with the user via graphical controls such as buttons and draggable titlebars and borders.
For a comprehensive overview of X Server and X Window System, consult the following article: https://en.wikipedia.org/wiki/X_server
All questions regarding this software should be directed at the Xorg mailing list:
https://lists.freedesktop.org/mailman/listinfo/xorg
The master development code repository can be found at:
https://gitlab.freedesktop.org/xorg/xserver
For patch submission instructions, see:
https://www.x.org/wiki/Development/Documentation/SubmittingPatches
As with other projects hosted on freedesktop.org, X.Org follows its Code of Conduct, based on the Contributor Covenant. Please conduct yourself in a respectful and civilized manner when using the above mailing lists, bug trackers, etc: