Re: [Xen-devel] [PATCH] tools: disable linker --as-needed option

["Jan Beulich" <JBeulich@xxxxxxxxxx>]

>>> On 01.02.11 at 10:27, Ian Campbell <Ian.Campbell@xxxxxxxxxxxxx> wrote:
> On Tue, 2011-02-01 at 09:21 +0000, Jan Beulich wrote:
>> >>> On 01.02.11 at 10:09, Ian Campbell <ian.campbell@xxxxxxxxxx> wrote:
>> > # HG changeset patch
>> > # User Ian Campbell <ian.campbell@xxxxxxxxxx>
>> > # Date 1296550939 0
>> > # Node ID a3fb60cc3be3dc6596ed8395e0eb70514bdfcc74
>> > # Parent  5b6663ba2bb2c54e8fa6745afa16297ebe43328d
>> > tools: disable linker --as-needed option.
>> > 
>> > The Xen build system is not currently compatible with the --as-needed
>> > linker option. The proper fix for this is turning out to be rather
>> > invasive to the build system so simply disable for now with the
>> > intention of revisiting for the 4.2 release.
>> > 
>> > The $(COMMA) trick allows "," in macro arguments.
>> > 
>> > Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
>> > Reported/Tested-by: Nathan March <nathan@xxxxxx>
>> > 
>> > diff -r 5b6663ba2bb2 -r a3fb60cc3be3 tools/Rules.mk
>> > --- a/tools/Rules.mk       Mon Jan 31 09:14:52 2011 +0000
>> > +++ b/tools/Rules.mk       Tue Feb 01 09:02:19 2011 +0000
>> > @@ -55,6 +55,10 @@ LDFLAGS += $(shell getconf LFS_LDFLAGS)
>> >  LDFLAGS += $(shell getconf LFS_LDFLAGS)
>> >  endif
>> >  
>> > +# Xen tools build is currently incompatible with ld --as-needed
>> > +COMMA := ,
>> > +LDFLAGS += $(call cc-option,$(CC),-Wl$(COMMA)--no-as-needed)
>> 
>> I don't think this actually works (Did you try with a linker not
>> supporting this option?), as cc-option is implemented passing
>> -S to the compiler (i.e. the linker won't even get invoked).
> 
> Er, no. I think you are probably right, I only tested with a linker
> which has the option defaulting to off and Nathan tested the default on
> case but noone actually tested the not available option.
> 
> Any idea how we can sensibly do this test?

No, not really (other than changing cc-option).

> I'm not even sure when
> --{no-,}as-needed came along, perhaps we don't actually need to worry?

2.15 has it (released in May 2004), 2.13.2 didn't. I don't have a
2.14 sitting around.

Jan


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