New Pass Manager Design ....

Project Infrastructure LLVM Dev List Archives
#1

Hi Chandler and All ,

Thank you for the new design on the pass manager ,http://llvm.org/devmtg/2014-10/Slides/Carruth-TheLLVMPassManagerPart2.pdf

We are coming up with new module pass ,that uses the region pass analysis (RPM),we have few queries like ,

a)can we model our requirements with your new design ,using the ModelToFunctionPassAdaptor /Proxies ?

b)Region Pass /Region Pass Manager uses the legacy pass manager and not refactored to new design ,Do you have plans for it ?

c)Any document for your new design ,other than mail threads or ppt doc ?

Will be highly appreciate any inputs here
~Umesh

#2

Hi Chandler and everyone ,
To be specific ,

We have the module pass ,that get the Function analysis Pass (RegionInfo) for each function and get populated to the vector RegionTree as show below . (assumption we have is that ,Every module has less than 16 functions for testing )

namespace {

struct TestPass : public ModulePass {
static char ID; // Pass identification, replacement for typeid
SmallVector<RegionInfo , 16> RegionTree;
TestPass() : ModulePass(ID) {
}

bool runOnModule(Module &M) override {
if (skipModule(M))
return false;
for (Function &Func : M) {

if (!Func.isDeclaration() && !Func.hasAvailableExternallyLinkage()) {
RegionTree.push_back(std::move(this->getAnalysis(Func).getRegionInfo()));
}

}
for (SmallVectorImpl::iterator RI = RegionTree.begin(),

RE = RegionTree.end();

RI != RE; ++RI) {

RI->dump();
}

return false;

}

void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.addRequired();
AU.addRequired();
}
};
}

char TestPass::ID = 0;
static RegisterPass
Z(“testpass”, “region Pass”);

Question is ,Can you(chandler ) or anyone in the dev list ,please help us to port the above module pass to new pass manager design ?

Any Doc or source will help us a lot

Thank you
~Umesh

#3

Hi Chandler and All ,

Thank you for the new design on the pass manager ,http://llvm.org/devmtg/2014-10/Slides/Carruth-TheLLVMPassManagerPart2.pdf

We are coming up with new module pass ,that uses the region pass analysis (RPM),we have few queries like ,

a)can we model our requirements with your new design ,using the ModelToFunctionPassAdaptor /Proxies ?

Almost certainly.

b)Region Pass /Region Pass Manager uses the legacy pass manager and not refactored to new design ,Do you have plans for it ?

I don’t have any specific plans here. But I think it should be possible to port. However, analysis-driven pass management is the most complicated part of this, and is only just now stabilizing after several iterations to figure out a design that works well.

I think it may be useful to watch how the Loop pass manager and analyses are ported to the end-state design in the next few months as an indication of what this will likely look like for regions.

That said, I don’t currently plan to work a lot on the region infrastructure in the near future, so if this is something you’re interested in I would definitely encourage you to dig into it and work on it.

c)Any document for your new design ,other than mail threads or ppt doc ?

At the moment, the header comments are the best documentation. The design, especially around analysis-based passes remains somewhat in flux. I’m definitely planning to write up more detailed documentation as the design starts to stabilize.