[Mesa-dev] [PATCH] Android: Fix LLVM duplicated symbols linking for N and M

[Emil Velikov]

On 23 August 2017 at 17:50, Rob Herring <robh at kernel.org> wrote:
> On Sun, Aug 20, 2017 at 2:57 PM, Rob Herring <robh at kernel.org> wrote:
>> On Fri, Aug 18, 2017 at 8:53 PM, Chih-Wei Huang <cwhuang at android-x86.org> wrote:
>>> 2017-08-19 8:27 GMT+08:00 Emil Velikov <emil.l.velikov at gmail.com>:
>>>> On 18 August 2017 at 20:46, Rob Herring <robh at kernel.org> wrote:
>>>>> Both statically linking libLLVMCore and dynamically linking libLLVM causes
>>>>> duplicated symbols in gallium_dri.so and it fails to dlopen. We don't
>>>>> really need to link libLLVMCore, but just need generated headers to be
>>>>> built first. Dynamically linking to libLLVM instead is enough to do
>>>>> that. Thanks to Qiang Yu for finding the root cause.
>
> [...]
>
>>>>>    $(if $(filter 7,$(MESA_ANDROID_MAJOR_VERSION)), \
>>>>> -    $(eval LOCAL_CFLAGS += -DHAVE_LLVM=0x0308 -DMESA_LLVM_VERSION_PATCH=0) \
>>>>> -    $(eval LOCAL_STATIC_LIBRARIES += libLLVMCore) \
>>>>> -    $(eval LOCAL_C_INCLUDES += external/llvm/include external/llvm/device/include),) \
>>>>> +    $(eval LOCAL_CFLAGS += -DHAVE_LLVM=0x0308 -DMESA_LLVM_VERSION_PATCH=0),) \
>>>>>    $(if $(filter O,$(MESA_ANDROID_MAJOR_VERSION)), \
>>>>> -    $(eval LOCAL_CFLAGS += -DHAVE_LLVM=0x0309 -DMESA_LLVM_VERSION_PATCH=0) \
>>>>> -    $(eval LOCAL_HEADER_LIBRARIES += llvm-headers),)
>>>>> +    $(eval LOCAL_CFLAGS += -DHAVE_LLVM=0x0309 -DMESA_LLVM_VERSION_PATCH=0),) \
>>>>> +  $(eval LOCAL_SHARED_LIBRARIES += libLLVM)
>>>> Am I the only person getting tad confused by amount of brackets?
>>>> As mentioned by Chih-Wei - a shell switch is not possible, but how
>>>> about a test vague like the following?
>>>>
>>>> test "x$(MESA_ANDROID_MAJOR_VERSION)" = "xO" &&
>>>>    $(eval LOCAL_CFLAGS += -DHAVE_LLVM=0x0309 -DMESA_LLVM_VERSION_PATCH=0)
>>>
>>> Only possible if you put it into $(shell ...)
>>> That gives me an idea. Maybe we ca do like
>>>
>>> $(shell case "$(MESA_ANDROID_MAJOR_VERSION)" in \
>>>             6) echo ... ;; \
>>>             7) echo ... ;; \
>>>             *)  echo ... ;; \
>>>             esac)
>>>
>>> I haven't really try it yet.
>>
>> What does either really buy us? It's really just bike shedding and
>> unrelated to fixing the problem at hand.
>>
>> I have another idea which is to use llvm-config and avoid the
>> conditionals altogether. I haven't looked into that closely though.
>
> Well, the build is broken again because the version changed from O to
> 8 (and I'm not sure if master is going to change to P or 9 at some
> point). So I went ahead and have this all coded up like this (I don't
> see a simple way to build and run llvm-config):
>
Yay :-(

>   $(eval $(shell sed -n -e
> 's/.*\(LLVM_VERSION_MAJOR\).*\([0-9].*\)/\1:=\2/p'
> external/llvm/device/include/llvm/Config/llvm-config.h)) \
>   $(eval $(shell sed -n -e
> 's/.*\(LLVM_VERSION_MINOR\).*\([0-9].*\)/\1:=\2/p'
> external/llvm/device/include/llvm/Config/llvm-config.h)) \
>   $(eval LOCAL_CFLAGS +=
> -DHAVE_LLVM=0x$(LLVM_VERSION_MAJOR)0$(LLVM_VERSION_MINOR))
>
> Only one slight problem in that for master/O it reports 3.8 as the
> version is 3.8.275480 which I think is the SVN version number. Not
> sure what to do with that...
>
Indeed, seems like a SVN version. Not sure how much to care about the
PATCH version.
Leave it as 0 or use the SVN one - your call.

Ideally there will be an LLVM API to query that at runtime... but
that's topic for another day.

-Emil