llvm dev - Mar 2014 - [LLVMdev] Build process ignores BUILD_CC?

Hi,

I am still struggling to cross-compile LLVM (using trunk).

My cross compiler builds code that cannot be run on the
build host. Thus, I need to make use of BUILD_CC/CXX during
configuration.

My current setup is (heavily boiled down):

../configure CC=cc_cross CXX=cxx_cross BUILD_CC=cc_host
BUILD_CXX=cxx_host (plus other flag stuff)

The configuration runs fine. However, when calling 'make' it
would construct the BuildTools in a way that doesn't pick
up the host compilers:

make
llvm[0]: Constructing LLVMBuild project information.

Looking into BuildTools/config.log I see a mere:

../configure --build=.. --host=.. --target=.. --disable-polly

Configuration fails of course, because it picks up the
host gcc which in my case has no C++11 support. Thus the
whole thing fails.

Am I right in thinking that in the BuildTools/ project it
would be the right thing to do to copy the BUILD_* variables
from the configuration as

BUILD_CC -> CC
BUILD_CXX -> CXX
(dito for the flags)?

If that's the case, then non of this is happening.

Thanks for your thoughts,
Frank

Meador posted a (quite old) patch yesterday that does this. I'll
follow up in that thread.

-eric

On Wed, Mar 19, 2014 at 2:01 PM, Frank Winter <fwinter at jlab.org>
wrote:
> Hi,
>
> I am still struggling to cross-compile LLVM (using trunk).
>
> My cross compiler builds code that cannot be run on the
> build host. Thus, I need to make use of BUILD_CC/CXX during
> configuration.
>
> My current setup is (heavily boiled down):
>
> ../configure CC=cc_cross CXX=cxx_cross BUILD_CC=cc_host
> BUILD_CXX=cxx_host (plus other flag stuff)
>
> The configuration runs fine. However, when calling 'make' it
> would construct the BuildTools in a way that doesn't pick
> up the host compilers:
>
> make
> llvm[0]: Constructing LLVMBuild project information.
>
> Looking into BuildTools/config.log I see a mere:
>
> ../configure --build=.. --host=.. --target=.. --disable-polly
>
> Configuration fails of course, because it picks up the
> host gcc which in my case has no C++11 support. Thus the
> whole thing fails.
>
> Am I right in thinking that in the BuildTools/ project it
> would be the right thing to do to copy the BUILD_* variables
> from the configuration as
>
> BUILD_CC -> CC
> BUILD_CXX -> CXX
> (dito for the flags)?
>
> If that's the case, then non of this is happening.
>
> Thanks for your thoughts,
> Frank
>
>
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev

I applied the patch and tried again.. it didn't work.

However, if I modify the patch to pass on the variables to the configure 
script, like

           $(PROJ_SRC_DIR)/configure --build=$(BUILD_TRIPLE) \
                 --host=$(BUILD_TRIPLE) --target=$(BUILD_TRIPLE) \
                 --disable-polly CC=$(CC) CXX=$(CXX) AR=$(AR) AS=$(AS) 
LD=$(LD) $$configure_opts; \

then it works.

Looks like (at least) my system doesn't load the variables automatically.

It should be safe to include these additional changes. But I am not 100% 
sure.

Frank


On 03/19/2014 05:08 PM, Eric Christopher wrote:
> Meador posted a (quite old) patch yesterday that does this. I'll
> follow up in that thread.
>
> -eric
>
> On Wed, Mar 19, 2014 at 2:01 PM, Frank Winter <fwinter at jlab.org>
wrote:
>> Hi,
>>
>> I am still struggling to cross-compile LLVM (using trunk).
>>
>> My cross compiler builds code that cannot be run on the
>> build host. Thus, I need to make use of BUILD_CC/CXX during
>> configuration.
>>
>> My current setup is (heavily boiled down):
>>
>> ../configure CC=cc_cross CXX=cxx_cross BUILD_CC=cc_host
>> BUILD_CXX=cxx_host (plus other flag stuff)
>>
>> The configuration runs fine. However, when calling 'make' it
>> would construct the BuildTools in a way that doesn't pick
>> up the host compilers:
>>
>> make
>> llvm[0]: Constructing LLVMBuild project information.
>>
>> Looking into BuildTools/config.log I see a mere:
>>
>> ../configure --build=.. --host=.. --target=.. --disable-polly
>>
>> Configuration fails of course, because it picks up the
>> host gcc which in my case has no C++11 support. Thus the
>> whole thing fails.
>>
>> Am I right in thinking that in the BuildTools/ project it
>> would be the right thing to do to copy the BUILD_* variables
>> from the configuration as
>>
>> BUILD_CC -> CC
>> BUILD_CXX -> CXX
>> (dito for the flags)?
>>
>> If that's the case, then non of this is happening.
>>
>> Thanks for your thoughts,
>> Frank
>>
>>
>> _______________________________________________
>> LLVM Developers mailing list
>> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
>> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev