[cfe-dev] Linking ProfileRT when using -nodefaultlibs

[Dan Albert]

Yes, that is the downside.

Has anyone actually run the tests against GCC recently? IIRC it requires
some local modifications anyway.

On Mon, Nov 10, 2014 at 11:40 AM, Eric Fiselier <eric at efcs.ca> wrote:

> > The reason we use -nodefaultlibs is to avoid linking the system's
> libc++. There's a -nostdinc++, maybe there should be a -nostdlib++? Or
> perhaps -stdlib=none?
> -nostdlib already exists but it acts like -nodefaultlibs and it drops the
> startup files as well.
> I would support -stdlib=none but I'm hesitant to start depending on Clang
> only flags. It would be nice to not have to special case GCC.
>
> /Eric
>
> On Mon, Nov 10, 2014 at 12:37 PM, Dan Albert <danalbert at google.com> wrote:
>
>> The reason we use -nodefaultlibs is to avoid linking the system's libc++.
>> There's a -nostdinc++, maybe there should be a -nostdlib++? Or perhaps
>> -stdlib=none?
>>
>> That would let us stop preventing the driver from doing its job...
>>
>> On Mon, Nov 10, 2014 at 11:26 AM, Eric Fiselier <eric at efcs.ca> wrote:
>>
>>> Thanks for the heads up about the dead link. I've attached the output to
>>> this email.
>>>
>>> I spent some time last night trying to fix this problem in Clang but I
>>> had no luck :(
>>> Moving the compiler-rt library before the linker inputs only created
>>> more issues.
>>>
>>> /Eric
>>>
>>> On Mon, Nov 10, 2014 at 11:40 AM, Justin Bogner <mail at justinbogner.com>
>>> wrote:
>>>
>>>> Eric Fiselier <eric at efcs.ca> writes:
>>>> > Hello,
>>>> >
>>>> > I'm working on making libc++ generate code coverage data. This means
>>>> that
>>>> > libclang_rt.profile.x86_64.a is put into the link command before
>>>> '-lc' and
>>>> > other dependencies.
>>>> > I suspect this change in library order causes the linker errors I see
>>>> while
>>>> > running the tests.
>>>> >
>>>> > I have a couple of questions:
>>>> >  - Should -ftest-coverage be passed when linking libc++?
>>>> >  - Is there a way to link libclang_rt.profile.x86_64.a after the
>>>> given linker
>>>> >    flags
>>>> >
>>>> > This file shows the ld invocation with and without -nodefaultlibs as
>>>> well as
>>>> > the error produced when
>>>> > linking tests w/ -nodefaultlibs
>>>> > http://pastebin.com/QWagJpsW
>>>>
>>>> There's nothing there? Mailing this text directly seems simpler than a
>>>> pastebin to me.
>>>>
>>>> This issue and a few other things I've seen recently make me think that
>>>> compiler-rt and -nodefaultlibs don't interact very well in general. I
>>>> guess there's work to be done in the area.
>>>>
>>>>
>>>
>>> _______________________________________________
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>>>
>>>
>>
>
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