[Mesa-dev] [PATCH 4/8] android: fix llvmpipe build

[Emil Velikov]

On 11 January 2017 at 19:19, Jose Fonseca <jfonseca at vmware.com> wrote:
> On 10/01/17 15:54, Emil Velikov wrote:
>>
>> On 6 January 2017 at 17:35, Wu Zhen <wuzhen at jidemail.com> wrote:
>>>
>>> From: WuZhen <wuzhen at jidemail.com>
>>>
>>> since (cf410574 gallivm: Make MCJIT a runtime optioni.), llvmpipe assume
>>> MCJIT is available on x86(_64). this is not the case for android prior to
>>> M.
>>>
>> Wu Zhen, what exactly is the issue you're getting - build or link-time
>> error ?
>>
>> Looking at the hunk [1] in the offending commit makes me wonder.
>>  - Why do we call LLVMLinkInJIT() even if one selects MCJIT via the env
>> var.
>>  - Why do we always call LLVMLinkInMCJIT regardless of a) if we've
>> build against old LLVM and b) the env var.
>>
>> Jose, shouldn't we honour the above ? One way that comes to mind is to
>> have USE_MCJIT always as static variable. Then we can guard the
>> debug_get_bool_option() override with the current LLVM_VERSION/ARCH
>> heuristics while preserving original invocation.
>>
>> if (USE_MCJIT) // use lowercase name since it's not a macro ?
>>    LLVMLinkInMCJIT();
>> else
>>    LLVMLinkInJIT();
>>
>>
>> Thanks
>> Emil
>>
>> [1]
>> @@ -385,18 +382,18 @@ lp_build_init(void)
>>    if (gallivm_initialized)
>>       return TRUE;
>>
>> +   LLVMLinkInMCJIT();
>> +#if !defined(USE_MCJIT)
>> +   USE_MCJIT = debug_get_bool_option("GALLIVM_MCJIT", 0);
>> +   LLVMLinkInJIT();
>> +#endif
>> +
>> #ifdef DEBUG
>>    gallivm_debug = debug_get_option_gallivm_debug();
>> #endif
>>
>>    lp_set_target_options();
>>
>> -#if USE_MCJIT
>> -   LLVMLinkInMCJIT();
>> -#else
>> -   LLVMLinkInJIT();
>> -#endif
>> -
>>
>
> USE_MCJIT used to be a statically define macro, but it's now it can also be
> runtime boolean.
>
> We require LLVM 3.3, and MCJIT has been available since then, so there was
> no reason not to link.
>
> Android seems a new beast: it has LLVM 3.3 but not MCJIT??
>
The Android discussion aside I was trying to point out that the commit
in question does more than making the compile time decision run-time
one.

Before the commit - LLVMLinkInMCJIT() was executed only when USE_MCJIT
is set, and after it's executed regardless. On the LLVMLinkInJIT front
- we seem to execute it even if the user has requested USE_MCJIT. I'm
either missing something here, or things look nasty/wrong ?

Thanks
Emil