[LLVMdev] UPCOMING API CHANGE: Threads and LLVM

[Owen Anderson]

Sandeep,

That's somewhat orthogonal to what is being worked on right now.

This is not an effort to make LLVM internally multithreaded, but to  
allow clients of the LLVM APIs to make multiple, concurrent calls into  
the APIs from multiple threads, which obviously necessitates guarding  
our internal state with mutexes.  Threading LLVM itself is another,  
even larger, undertaking.

--Owen

On Jun 15, 2009, at 6:53 PM, Sandeep Patel wrote:

> This question is a bit of far away future thought:
>
> There's traditionally been a fundamental assumption that static
> compilers are single-threaded. Many build systems assume this and
> support assigning compilation jobs with one job per processor.
>
> If the compiler becomes multi-threaded internally, how should the
> build system best schedule compilation jobs?
>
> deep
>
> On Mon, Jun 15, 2009 at 6:16 PM, Owen Anderson<resistor at mac.com>  
> wrote:
>> Hey folks,
>>
>> As you may be aware if you've been watching llvm-commits, I've been
>> working recently on improving the ability to use LLVM across multiple
>> threads.  While the goal for now is to be able to hack on multiple
>> Module's in parallel, this has necessitated a larger review of how
>> LLVM interacts with threads.
>>
>> In a recent(-ish) patch, I added a new API: llvm_start_multithreaded
>> ().  This API is used to initialize the thread-safety constructs that
>> are going into LLVM.  I will be committing a detail update to the  
>> LLVM
>> programmer's manual on how to use it.
>>
>> The major CHANGE is:  the JIT will no longer be safe for executing
>> threaded applications without first invoking llvm_start_multithreaded
>> ().  Please begin to update your client applications now if this
>> affects you, as I will be throwing the switch in SVN sooner rather
>> than later.
>>
>> Thanks,
>>
>> --Owen
>> _______________________________________________
>> LLVM Developers mailing list
>> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
>> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
>>
>
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev

-------------- next part --------------
A non-text attachment was scrubbed...
Name: smime.p7s
Type: application/pkcs7-signature
Size: 2620 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20090615/3a387cb5/attachment.bin>