RFC: drop support for gcc < 4.0

[Adrian Bunk <bunk@kernel.org>]

On Tue, Aug 21, 2007 at 09:31:03AM -0700, Randy Dunlap wrote:
> On Tue, 21 Aug 2007 15:20:38 +0200 Jarek Poplawski wrote:
> 
> > Here are some more of, probably well-known, warnings with attached
> > testing-only .config.
> >...
> > drivers/pci/msi.c:686: warning: weak declaration of `arch_msi_check_device' after first use results in unspecified behavior
> > drivers/pci/msi.c:698: warning: weak declaration of `arch_setup_msi_irqs' after first use results in unspecified behavior
> > drivers/pci/msi.c:718: warning: weak declaration of `arch_teardown_msi_irqs' after first use results in unspecified behavior
> >...
> 
> What gcc version?  I don't get the arch_ warnings in drivers/pci/msi.c.

Obviously a gcc <= 3.4 [1], and therefore no unit-at-a-time.

You can reproduce it with a more recent gcc when adding 
-fno-unit-at-a-time to the CFLAGS.

And it's becoming a real maintainance problem that not only this problem 
but also other problems like some section mismatches [2] are only 
present without unit-at-a-time.

Currently we support 6 different stable gcc release series, and it might 
be the right time to consider dropping support for the older ones.

Are there any architectures still requiring a gcc < 4.0 ?

> ~Randy

cu
Adrian

[1] unit-at-a-time was added in gcc 3.4, but on gcc 3.4 we disable it on
    i386 due to stack usage problems
[2] example: static __init function with exactly one caller, and this
             caller is non-__init

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