Hi All,
If you compile jchuff.c (part of javajpeg) without
"--disable-warnings-as-errors",
then you get an error that kills the build. This is seen in these
circumstances:
Build: JDK9
gcc and g++ Version: 4.8.5
Platform: zLinux 64bit (s390x)
The error message is:
/home/adamfarl/hotspot/jdk9/jdk/src/java.desktop/share/native/libjavajpeg/jchuff.c:
In function 'jGenOptTbl':
/home/adamfarl/hotspot/jdk9/jdk/src/java.desktop/share/native/libjavajpeg/jchuff.c:808:18:
error: array subscript is below array bounds [-Werror=array-bounds]
while (bits[j] == 0)
^
It looks to me that this error happens because the while loop can
technically
reduce j down to beneath 0, resulting in us attempting to find the array
entry
with index -1.
On the basis that if we get down to -1 here bad things will happen
regardless,
perhaps we should change that line to:
while ((bits[j] == 0) && (j != 0))
This appears to prevent the compiler failing with this error, by providing
unambiguous handling for the "index -1" scenario.
Thoughts?
Best Regards
Adam Farley
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