[cfe-dev] Linking ProfileRT when using -nodefaultlibs

Dan Albert danalbert at google.com
Mon Nov 10 11:37:52 PST 2014


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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