[LLVMdev] Compiler-RT on Buildbots

[Renato Golin]

On 28 May 2014 17:44, Justin Bogner <mail at justinbogner.com> wrote:
> In the autoconf system, I'm pretty sure compiler-rt's build is triggered
> by a Makefile in clang, tools/clang/runtime/compiler-rt/Makefile. This
> Makefile comments "We currently only try to generate runtime libraries
> on x86", so I guess that's the place to start if you want to get it to
> build on ARM.

Hi Justin,

I'm having a go at autoconf-driven RT on ARM.

Without any change, autoconf doesn't even know compiler-rt is there.
Then, I added this:

ifeq ($(ARCH),ARM)
RuntimeLibrary.linux.Configs += builtins-ARM.a # rest to come once
this is working
endif

And I do get the build system to recognise, complain about ld not
supporting x86 on darwin:

warning: clang_darwin.mk: dropping arch 'i386' from lib '10.4' (ld
does not support it)
warning: clang_darwin.mk: dropping arch 'x86_64' from lib '10.4' (ld
does not support it)

and then the following error:

make[5]: Entering directory `/work/llvm/src/projects/compiler-rt'
make[5]: Nothing to be done for `clang_linux'.
make[5]: Leaving directory `/work/llvm/src/projects/compiler-rt'
llvm[4]: Copying runtime library linux/builtins-ARM to build dir
cp: cannot stat
‘/work/llvm/build/tools/clang/runtime/compiler-rt/clang_linux/builtins-ARM/libcompiler_rt.a’:
No such file or directory
make[4]: *** [/work/llvm/build/Release+Asserts/lib/clang/3.5.0/lib/linux/libclang_rt.builtins-ARM.a]
Error 1
rm /work/llvm/build/Release+Asserts/lib/clang/3.5.0/lib/linux/.dir
make[4]: Leaving directory `/work/llvm/build/tools/clang/runtime/compiler-rt'

I'm guessing the "nothing to be done" is the real culprit here, and comes from:

BuildRuntimeLibraries:
        $(Verb) $(MAKE) -C $(COMPILERRT_SRC_ROOT) \
          ProjSrcRoot=$(COMPILERRT_SRC_ROOT) \
          ProjObjRoot=$(PROJ_OBJ_DIR) \
          CC="$(ToolDir)/clang" \
          LLVM_ANDROID_TOOLCHAIN_DIR="$(LLVM_ANDROID_TOOLCHAIN_DIR)" \
          $(COMPILERRT_MAKE_FLAGS) \
          $(RuntimeDirs:%=clang_%)

which executes the compiler-rt Makefile, which is where the
compiler-rt files are built.

This is what comes out:

make -C /work/llvm/src/projects/compiler-rt \
 ProjSrcRoot=/work/llvm/src/projects/compiler-rt \
 ProjObjRoot=/work/llvm/build/tools/clang/runtime/compiler-rt \
 CC="/work/llvm/build/Release+Asserts/bin/clang" \
 LLVM_ANDROID_TOOLCHAIN_DIR="" \
  \
 clang_linux

When I run "make info-platforms" in compiler-rt, "clang_linux" is one
of them, so I added some ARM stuff to make/platform/clang_linux.mk to
no avail.

I'm also curious as to why the ld error mentioned above is on
clang_darwin.mk not clang_linux.mk, since this is clearly what it
should be running...

Any ideas? I'm not the most knowledgeable on autoconf/cmake stuff, as
you can see. :)

Thanks!
--renato