llvm dev - May 2009 - [LLVMdev] [PATCH] llvm-config: add svn revision to --version

At the moment llvm-config outputs "2.6svn" if llvm is build from trunk

$ llvm-config --version
2.6svn

Some external projects (built out-of-tree) need to know which revision  
of llvm is installed. LDC currently asks llvm-config --src-root for  
the source directory and then parses svn info's output to get the  
revision number. This requires the user to keep the llvm source tree  
around even if it is not needed to build ldc.

The attached patch modifies the llvm build system (both autotools and  
cmake) to write the revision into PACKAGE_VERSION:

$ llvm-config --version
2.6-71981

or, if it couldn't find svn during the build:

$ llvm-config --version
2.6-svn

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Benjamin Kramer wrote:
> At the moment llvm-config outputs "2.6svn" if llvm is build from
trunk
> 
> $ llvm-config --version
> 2.6svn
> 
> Some external projects (built out-of-tree) need to know which revision 
> of llvm is installed. LDC currently asks llvm-config --src-root for the 
> source directory and then parses svn info's output to get the revision 
> number. This requires the user to keep the llvm source tree around even 
> if it is not needed to build ldc.
Not technically true; it's not *required*. However, if this isn't done
you need
to set it manually in the cmake configuration...
> The attached patch modifies the llvm build system (both autotools and 
> cmake) to write the revision into PACKAGE_VERSION:
> 
> $ llvm-config --version
> 2.6-71981
I don't think that's enough for LDC; we want to be able to compare the
version
with #if, so we need it to produce something like '#define LLVM_REV
71981' (i.e.
a raw integer, not a string).

> I don't think that's enough for LDC; we want to be able to compare
the version
> with #if, so we need it to produce something like '#define LLVM_REV
71981' (i.e.
> a raw integer, not a string).
Why don't introduce some another option for it? E.g. llvm-config --revision
?

-- 
With best regards, Anton Korobeynikov
Faculty of Mathematics and Mechanics, Saint Petersburg State University

Frits van Bommel wrote:
> I don't think that's enough for LDC; we want to be able to compare
> the version
> with #if, so we need it to produce something like '#define LLVM_REV  
> 71981' (i.e.
> a raw integer, not a string).
Here is another patch which adds a new option to llvm-config:

$ llvm-config --revision


or, if the build script couldn't find svn:

$ llvm-config --revision
0

I think this is also a safer approach, it won't break anything that  
relies on the
current llvm-config behavior.

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Frits van Bommel skrev:
> Benjamin Kramer wrote:
>   
>> At the moment llvm-config outputs "2.6svn" if llvm is build
from trunk
>>
>> $ llvm-config --version
>> 2.6svn
>>
>> Some external projects (built out-of-tree) need to know which revision 
>> of llvm is installed. LDC currently asks llvm-config --src-root for the
>> source directory and then parses svn info's output to get the
revision
>> number. This requires the user to keep the llvm source tree around even
>> if it is not needed to build ldc.
>>     
>
> Not technically true; it's not *required*. However, if this isn't
done you need
> to set it manually in the cmake configuration...
>
>   
>> The attached patch modifies the llvm build system (both autotools and 
>> cmake) to write the revision into PACKAGE_VERSION:
>>
>> $ llvm-config --version
>> 2.6-71981
>>     
>
> I don't think that's enough for LDC; we want to be able to compare
the version
> with #if, so we need it to produce something like '#define LLVM_REV
71981' (i.e.
> a raw integer, not a string).
>   
When we build Icedtea shark JIT we use the llvm-config version to make 
the icedtea code compatible with api changes in llvm.
I belive you are trying to do something similarwith LDC. This can be 
done without changing the llvm codebase.

I suggest the following:
add to the LDC configure.

LLVM_CFLAGS="$LLVM_CFLAGS -DLLVM_VERSION=`$LLVM_CONFIG --version | sed
's/\.//;s/svn.*//'`"

this will take the llvm-config --version output and truncates the versionnumber
from

2.6svn to 26

now the LLVM_VERSION can be used in your source code like this:

#if LLVM_VERSION >= 26
/*llvm 2.6 and above compatible code*/
#endif

#if LLVM_VERSION >= 25
// etc...
#endif

cheers
Xerxes