doko at ubuntu.com
Tue Nov 9 16:15:52 UTC 2010
On 09.11.2010 14:05, Andrew Stubbs wrote:
> On 09/11/10 06:51, Michael Hope wrote:
>> I've been going through the ChangeLog for the release and am having
>> trouble justifying some of the changes brought in. In particular:
>> * -fstrict-volatile-bitfields, which is more appropriate for bare
>> metal/kernel code
>> * Cortex-M4 support
>> * C locale support in libstdc++-v3
> These changes were brought in on the (secondary) principle of keeping Sourcery
> G++ and Linaro GCC as closely related as possible.
> There are two main advantages to this policy:
> 1. Future merges are easier if the sources have not diverged.
> 2. Each toolchain benefits from the other's testing efforts.
> This principle has been acknowledged from the beginning of this project.
> Note: the two are *not* exactly the same - some patches that customize SG++ in
> ways that would not be acceptable upstream have been omitted - but they do not
> diverge to wildly.
The main disadvantage of this policy for 4.4 were build failures for some
packages in Ubuntu, introduced by non ARM related changes compared to the FSF
GCC. Linaro isn't tasked with *finding* these build issues, so this is extra
work on the Ubuntu side. I don't see how the first two changes mentioned above
could introduce the build failures, would have to look at the third issue. In
general I would like to see a changed policy for future Linaro releases to be
more strict with some user visible behavioural changes.
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