----- Original Message ----- > I suppose the problem that some new version of GCC enables this > option > by default and > we could run into a problem at run time if we don't disable it ? >
Yes, 4.4 to be precise. It's not particularly new; it came out on April 21st, 2009. > But this patch would appear to disable it for the whole ICU library > .. > and any other C++ code in the .so > which I would have to suppose impacts the compiler's ability to > optimise > the code, in order to > eliminate a single warning. > > Can you devise a more targeted fix ? > Yes, I thought the same. But I don't see how you can direct flags to one specific file in the Makefiles. Any ideas? Alternatively, is this READ_LONG macro even necessary? I'm not surprised gcc balks at it to be honest. > -phil. > > On 5/23/2012 5:59 AM, Andrew Hughes wrote: > > At present, the building of ExtensionSubtables.cpp produces a > > warning: > > > > ../../../src/share/native/sun/font/layout/ExtensionSubtables.cpp:57:31: > > warning: dereferencing type-punned pointer will break > > strict-aliasing rules [-Wstrict-aliasing] > > > > due to this code: > > > > // read a 32-bit value that might only be 16-bit-aligned in memory > > #define READ_LONG(code) (le_uint32)((SWAPW(*(le_uint16*)&code)<< > > 16) + SWAPW(*(((le_uint16*)&code) + 1))) > > > > where code is a le_uint32. > > > > This can be avoided by setting -fno-strict-aliasing, as done in > > this webrev: > > > > http://cr.openjdk.java.net/~andrew/no-strict-aliasing/ > > > > making the code safer in the process. > > > > Ok for jdk8? If so, can I have a bug ID for this please? > > > > Thanks, > > -- Andrew :) Free Java Software Engineer Red Hat, Inc. (http://www.redhat.com) PGP Key: 248BDC07 (https://keys.indymedia.org/) Fingerprint = EC5A 1F5E C0AD 1D15 8F1F 8F91 3B96 A578 248B DC07
