[llvm-dev] About LLVM Pass dependency

[Hongbin Zheng via llvm-dev]

AnalysisUsage also apply to transformation pass. For example, a lot of pass
requires LCSSA and BreakCriticalEdge, which are transformations.

On Tue, Oct 3, 2017 at 10:30 AM, Mahesh Attarde <coder.mahesh at gmail.com>
wrote:

> Hi Hongbin
>
> I am not quite familiar with AnalysisUsage, let me correct question a bit.
> I have read Writing Pass
> <http://llvm.org/docs/WritingAnLLVMPass.html#specifying-interactions-between-passes>,
> All examples that i see here are based on collecting information .i.e
> Analysis Passes.
> I wonder if this applies to Transformation passes also.
> e.g.
>
> void MyInliner::getAnalysisUsage(AnalysisUsage &AU) const {
>    AU.addRequired<SimplifyCFGPass>();    // Transformation Pass
>    AU.addRequired<AnnotatedFunctionPass>();  // Transformation like pass
>    AU.addRequired<CallGraphSCCPass>();    // Analysis Pass
> }
>
> here AnnotateFunctionPass is adding meta information,so technically
> nothing Functional transformational in module and
> not Analysis either.
> Would that be right way?
>
> Thanks
> Mahesh
>
> On Tue, Oct 3, 2017 at 9:43 PM, Hongbin Zheng <etherzhhb at gmail.com> wrote:
>
>> Hi Mahesh,
>>
>> Did you override getAnalysisUsage and require D1, D2 and D3?
>>
>>
>> void YourPass::getAnalysisUsage(AnalysisUsage &AU) const {
>>   AU.addRequired<D1>();
>>   AU.addRequired<D2>();
>>   AU.addRequired<D3>();
>> }
>>
>> On Tue, Oct 3, 2017 at 2:00 AM, Mahesh Attarde via llvm-dev <
>> llvm-dev at lists.llvm.org> wrote:
>>
>>> Hello
>>>   I am working on pass which has dependency on multiple passes.  Say
>>> D1,D2,D3
>>> I used
>>> INITIALIZE_PASS_BEGIN
>>> INITIALIZE_PASS_DEPENDENCY(D1)
>>> INITIALIZE_PASS_DEPENDENCY(D2)
>>> INITIALIZE_PASS_DEPENDENCY(D3)
>>> INITIALIZE_PASS_END.
>>>
>>> While running it through opt tool it, I had to specify this D1,D2,D3
>>> pass names
>>> to get this pass executed before my pass.
>>> Is there way, to let llvm pass manager to know  execute all dependencies
>>> without
>>> having to specify explicitly.?
>>>
>>> I suspect i am doing something wrong in my code, May be.
>>>
>>> Thanks
>>> Mahesh
>>>
>>> _______________________________________________
>>> LLVM Developers mailing list
>>> llvm-dev at lists.llvm.org
>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>>>
>>>
>>
>
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