llvm dev - May 2016 - Why can't clang -emit-llvm when linking?

When I try to do 

clang++ main.cpp -emit-llvm

without -S, clang says that he can’t:

clang: error: -emit-llvm cannot be used when linking


why can’t it emit the IR in a complete compilation process?

Is there a particular technical reason or just to avoid confusing jobs?
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There is no single LLVM IR for the entire compilation process in such a
command line - separate IR is created for each source file, an object file
is created, then those (native, non-IR) object files are linked together.
So it's somewhat a invalid concept.

In your case, since there's only one file anyway, just add -c and you
should be fine (your IR won't include the standard library/other thingsn
that would be linked into the program - but those would be native objects
and not IR in any case)

- Dave

On Mon, May 30, 2016 at 5:33 AM, Lorenzo Laneve via llvm-dev <
llvm-dev at lists.llvm.org> wrote:
> When I try to do
>
> clang++ main.cpp -emit-llvm
>
> without -S, clang says that he can’t:
>
> clang: error: -emit-llvm cannot be used when linking
>
>
> why can’t it emit the IR in a complete compilation process?
>
> Is there a particular technical reason or just to avoid confusing jobs?
>
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>
>
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I know right, but if I do -emit-llvm clang will emit an IR module as .ll file
for each source I give him. So why can't it just emit the modules for the
sources and then continue the compilation? I don't get the point of this
error. Just for curiosity
> On May 30, 2016, at 6:17 PM, David Blaikie <dblaikie at gmail.com>
wrote:
> 
> There is no single LLVM IR for the entire compilation process in such a
command line - separate IR is created for each source file, an object file is
created, then those (native, non-IR) object files are linked together. So
it's somewhat a invalid concept.
> 
> In your case, since there's only one file anyway, just add -c and you
should be fine (your IR won't include the standard library/other thingsn
that would be linked into the program - but those would be native objects and
not IR in any case)
> 
> - Dave
> 
>> On Mon, May 30, 2016 at 5:33 AM, Lorenzo Laneve via llvm-dev
<llvm-dev at lists.llvm.org> wrote:
>> When I try to do 
>> 
>> clang++ main.cpp -emit-llvm
>> 
>> without -S, clang says that he can’t:
>> 
>> clang: error: -emit-llvm cannot be used when linking
>> 
>> 
>> why can’t it emit the IR in a complete compilation process?
>> 
>> Is there a particular technical reason or just to avoid confusing jobs?
>> 
>> _______________________________________________
>> LLVM Developers mailing list
>> llvm-dev at lists.llvm.org
>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
> 
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