llvm dev - Nov 2012 - [LLVMdev] Avoiding the emission of metadata

On Thu, Nov 1, 2012 at 10:04 PM, Zhoujinguo <zhoujinguo1988 at yahoo.cn>
wrote:
> Hi,
>
> I am interested in building some large projects to get single .bc files.
> Is there an easy way to do this? Or do I have to go through and understand
> the whole makefile script?
>
This is what LLVM's "LTO" (Link Time Optimization) does,
basically. This is
triggered by building with -O4 and you'd need to use an LTO-aware linker
(like gold) to handle the link step. I'm not sure how you'd actually
dump
out bitcode from the linker, rather than a final binary - but that's
more-or-less where you'd get involved.

I realize this is a bit vague (as I'm by no means an expert on the matter)
but thought it might be at least a pointer to some ideas/approach.

- David
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02.11.2012, 10:55, "David Blaikie" <dblaikie at
gmail.com>:
> On Thu, Nov 1, 2012 at 10:04 PM, Zhoujinguo <zhoujinguo1988 at
yahoo.cn> wrote:
>> Hi,
>> I am interested in building some large projects to get single .bc
files. Is there an easy way to do this? Or do I have to go through and
understand the whole makefile script?
> This is what LLVM's "LTO" (Link Time Optimization) does,
basically. This is triggered by building with -O4 and you'd need to use an
LTO-aware linker (like gold) to handle the link step. I'm not sure how
you'd actually dump out bitcode from the linker, rather than a final binary
- but that's more-or-less where you'd get involved.
Instead of using linker, you can call all .o files and process them - when
building with -O4 they contain bitcode.

-- 
Regards,
Konstantin

Hi all

is it possible to avoid the emission of metadata information by opt  
and/or clang?

For instance, I would like to go without "tbaa" metadata in LLVM  
assembly code as printed by "-emit-llvm".

I'm using the 3.1 binary release for MinGW (and for Linux on a  
different machine).

Best regards
Nikolaos Kavvadias

You can turn off TBAA metadata by passing -fno-strict-aliasing to clang.  You
can turn off emitting debug metadata by not passing -g.  There is no flag for
turning off metadata in general (for example, range metadata will still be
produced for certain casts, and if you compile Objective-C for the GNU runtimes
then you will still have some metadata attached to message sends.  If you want
to remove all metadata, then you will need to strip it off explicitly, but that
leads to the question of what problem you are actually trying to solve.

David

On 2 Nov 2012, at 09:37, nkavv at physics.auth.gr wrote:
> Hi all
> 
> is it possible to avoid the emission of metadata information by opt and/or
clang?
> 
> For instance, I would like to go without "tbaa" metadata in LLVM
assembly code as printed by "-emit-llvm".
> 
> I'm using the 3.1 binary release for MinGW (and for Linux on a
different machine).
> 
> Best regards
> Nikolaos Kavvadias
> 
> 
> 
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