[llvm-dev] Function optimization pass

[Ta Thanh Dinh via llvm-dev]

I've managed somehow to pass the fp_manager.run using:

auto loop_manager = llvm::LoopAnalysisManager{};
auto cgscc_manager = llvm::CGSCCAnalysisManager{};
auto mod_manager = llvm::ModuleAnalysisManager{};

pass_builder.registerModuleAnalyses(mod_manager);
pass_builder.registerCGSCCAnalyses(cgscc_manager);
pass_builder.registerFunctionAnalyses(fa_manager);
pass_builder.registerLoopAnalyses(loop_manager);
pass_builder.crossRegisterProxies(loop_manager, fa_manager, cgscc_manager,
mod_manager);

auto fp_manager =
pass_builder.buildFunctionSimplificationPipeline(llvm::PassBuilder::OptimizationLevel::O2,
llvm::PassBuilder::ThinLTOPhase::None, true);

fp_manager.run(*lift_func, fa_manager);

...print module...

but the program still crashes when the object `fa_manager` (of class
FunctionAnalysisManager) is destroyed!!!

Le mar. 21 août 2018 à 14:32, Ta Thanh Dinh <tathanhdinh at gmail.com> a
écrit :

> Hi Philip,
>
> Thanks for the response. Under llvm-5.0.2 and llvm-6.0.1 in Debug mode,
> the crash hit at the same assertion:
>
> /usr/local/include/llvm/IR/PassManager.h:689: typename PassT::Result&
> llvm::AnalysisManager<IRUnitT, ExtraArgTs>::getResult(IRUnitT&, ExtraArgTs
> ...) [with PassT =
> llvm::InnerAnalysisManagerProxy<llvm::AnalysisManager<llvm::Loop,
> llvm::LoopStandardAnalysisResults&>, llvm::Function>; IRUnitT =
> llvm::Function; ExtraArgTs = {}; typename PassT::Result =
> llvm::InnerAnalysisManagerProxy<llvm::AnalysisManager<llvm::Loop,
> llvm::LoopStandardAnalysisResults&>, llvm::Function>::Result]: Assertion
> `AnalysisPasses.count(PassT::ID()) && "This analysis pass was not
> registered prior to being queried"' failed.
>
> I'm new to llvm optimization and I still don't know which analysis
> managers should be created and populated in this case. Many thanks for any
> help.
>
>
> Le mar. 21 août 2018 à 14:00, Philip Pfaffe <philip.pfaffe at gmail.com> a
> écrit :
>
>> Can you tell us more about the crash? I.e., do you have a stack dump?
>> Does it hit an assertion (if your LLVM is built in Debug mode/has
>> assertions enabled)?
>>
>> Generally, PassBuilder and passes likely assume a full stack of analysis
>> managers. You should thus create and populate all of them, not just
>> FunctionAM, and cross-register their proxies.
>>
>> Cheers,
>> Philip
>>
>> On Mon, Aug 20, 2018 at 7:29 PM Ta Thanh Dinh via llvm-dev <
>> llvm-dev at lists.llvm.org> wrote:
>>
>>> This question has been submitted to stackoverflow (
>>> https://stackoverflow.com/questions/51934964/function-optimization-pass)
>>> but someone suggested me that it should be submitted to llvm-dev mailing
>>> list instead. I'm sorry for the duplication.
>>>
>>> I am trying to use PassBulider and FunctionPassManager to optimize a
>>> function in a module, what I have done is:
>>>
>>>
>>> mod = ...load module from LLVM IR bitcode file go_back.bc...
>>>
>>> auto lift_func = mod->getFunction("go_back");
>>> if (not lift_func) {
>>>     llvm::errs() << "Error: cannot get function\n";
>>>     return 0;
>>> }
>>>
>>> auto pass_builder = llvm::PassBuilder{};
>>> auto fa_manager = llvm::FunctionAnalysisManager{};
>>>
>>> pass_builder.registerFunctionAnalyses(fa_manager);
>>> auto fp_manager =
>>> pass_builder.buildFunctionSimplificationPipeline(llvm::PassBuilder::OptimizationLevel::O2);
>>>
>>> fp_manager.run(*lift_func, fa_manager);
>>>
>>> ...print mod...
>>>
>>>
>>> but the program crashes always at fp_manager.run. Strange enough, LLVM's
>>> opt tool (which uses legacy optimization API) works without any problem,
>>> i.e if I run
>>>
>>> opt -O2 go_back.bc -o go_back_o2.bc
>>>
>>> then I get a new module where the (single) function go_back is optimized.
>>>
>>> Many thanks for any response.
>>>
>>> NB. The disassembled LLVM bitcode is at
>>> https://gist.github.com/tathanhdinh/23470452910da9f73b857b2e6a12f144 if
>>> anyone wants to take a look.
>>> _______________________________________________
>>> LLVM Developers mailing list
>>> llvm-dev at lists.llvm.org
>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>>>
>>
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