[llvm-dev] How does -fPIE get passed from clang to llc when run on a .ll file?

[Akira Hatanaka via llvm-dev]

If the target platform is linux and -fPIE is on the command line, clang
sets TargetOptions::PositionIndependentExecutable in
EmitAssemblyHelper::CreateTargetrMachine.

On Fri, Nov 6, 2015 at 11:20 AM, Phil Tomson via llvm-dev <
llvm-dev at lists.llvm.org> wrote:

>
>
> On Fri, Nov 6, 2015 at 11:10 AM, Tim Northover <t.p.northover at gmail.com>
> wrote:
>
>> On 6 November 2015 at 11:00, Phil Tomson <phil.a.tomson at gmail.com> wrote:
>> > With 3.6 I get an unused argument warning with -enable-pie:
>> >
>> > $ clang -v -emit-llvm -enable-pie -O0 -S global_dat.c -o
>> > global_dat_x86_pie.ll
>>
>> Yes, it's an llc option not a Clang option. It actually looks like
>> Clang doesn't forward it to LLVM at all (almost certainly a bug, if
>> so). But that's probably OK because the only place LLVM actually uses
>> it at all is to determine what kind of TLS model to use
>> (TargetMachine.cpp), which linkers can mostly relax anyway.
>>
>
> In my case I'm actually working on a backend for a new architecture and
> need this to show up in LLVM because certain pseudo ops need to be expanded
> in a certain way if we're using PIE (vs. just a default static link). So
> are these options accessible in the Target-specific code?
>
>>
>> It does seem to get passed onto the linker by Clang though.
>>
>
> Not sure how that can work.
>
>
>> Cheers.
>>
>> Tim.
>>
>
>
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20151106/15ad9f0f/attachment.html>