[NewPM] Add OptimizationLevel param to registerPipelineStartEPCallback

[aeubanks]

Summary

This allows targets to skip optional optimization passes at -O0.

[ychen]

LGTM

llvm/include/llvm/Passes/PassBuilder.h

public:
   }
 
   /// Register a callback for a default optimizer pipeline extension point.
   ///
   /// This extension point allows adding optimization once at the start of the
   /// pipeline. This does not apply to 'backend' compiles (LTO and ThinLTO
   /// link-time pipelines).
   void registerPipelineStartEPCallback(
-      const std::function<void(ModulePassManager &)> &C) {
+      const std::function<void(ModulePassManager &, OptimizationLevel)> &C) {
     PipelineStartEPCallbacks.push_back(C);
   }
 
   /// Register a callback for a default optimizer pipeline extension point
   ///
   /// This extension point allows adding optimizations at the very end of the
   /// function optimization pipeline. A key difference between this and the
   /// legacy PassManager's OptimizerLast callback is that this extension point
SmallVector<std::function<void(FunctionPassManager &, OptimizationLevel)>, 2>
       ScalarOptimizerLateEPCallbacks;
   SmallVector<std::function<void(CGSCCPassManager &, OptimizationLevel)>, 2>
       CGSCCOptimizerLateEPCallbacks;
   SmallVector<std::function<void(FunctionPassManager &, OptimizationLevel)>, 2>
       VectorizerStartEPCallbacks;
   SmallVector<std::function<void(ModulePassManager &, OptimizationLevel)>, 2>
       OptimizerLastEPCallbacks;
   // Module callbacks
-  SmallVector<std::function<void(ModulePassManager &)>, 2>
+  SmallVector<std::function<void(ModulePassManager &, OptimizationLevel)>, 2>
       PipelineStartEPCallbacks;
   SmallVector<std::function<void(ModuleAnalysisManager &)>, 2>
       ModuleAnalysisRegistrationCallbacks;
   SmallVector<std::function<bool(StringRef, ModulePassManager &,
                                  ArrayRef<PipelineElement>)>,
               2>
       ModulePipelineParsingCallbacks;
   SmallVector<std::function<bool(ModulePassManager &, ArrayRef<PipelineElement>,

llvm/lib/Passes/PassBuilder.cpp

PassBuilder::buildPerModuleDefaultPipeline(OptimizationLevel Level,
 
   ModulePassManager MPM(DebugLogging);
 
   // Force any function attributes we want the rest of the pipeline to observe.
   MPM.addPass(ForceFunctionAttrsPass());
 
   // Apply module pipeline start EP callback.
   for (auto &C : PipelineStartEPCallbacks)
-    C(MPM);
+    C(MPM, Level);
 
   if (PGOOpt && PGOOpt->SamplePGOSupport)
     MPM.addPass(createModuleToFunctionPassAdaptor(AddDiscriminatorsPass()));
 
   // Add the core simplification pipeline.
   MPM.addPass(buildModuleSimplificationPipeline(Level, ThinLTOPhase::None));
 
   // Now add the optimization pipeline.
PassBuilder::buildThinLTOPreLinkDefaultPipeline(OptimizationLevel Level) {
   // Force any function attributes we want the rest of the pipeline to observe.
   MPM.addPass(ForceFunctionAttrsPass());
 
   if (PGOOpt && PGOOpt->SamplePGOSupport)
     MPM.addPass(createModuleToFunctionPassAdaptor(AddDiscriminatorsPass()));
 
   // Apply module pipeline start EP callback.
   for (auto &C : PipelineStartEPCallbacks)
-    C(MPM);
+    C(MPM, Level);
 
   // If we are planning to perform ThinLTO later, we don't bloat the code with
   // unrolling/vectorization/... now. Just simplify the module as much as we
   // can.
   MPM.addPass(buildModuleSimplificationPipeline(Level, ThinLTOPhase::PreLink));
 
   // Run partial inlining pass to partially inline functions that have
   // large bodies.

llvm/lib/Target/BPF/BPFTargetMachine.cpp

Builder.addExtension(
       PassManagerBuilder::EP_ModuleOptimizerEarly,
       [&](const PassManagerBuilder &, legacy::PassManagerBase &PM) {
         PM.add(createBPFAdjustOpt());
       });
 }
 
 void BPFTargetMachine::registerPassBuilderCallbacks(PassBuilder &PB,
                                                     bool DebugPassManager) {
-  PB.registerPipelineStartEPCallback([=](ModulePassManager &MPM) {
+  PB.registerPipelineStartEPCallback(
+      [=](ModulePassManager &MPM, PassBuilder::OptimizationLevel) {
         FunctionPassManager FPM(DebugPassManager);
         FPM.addPass(BPFAbstractMemberAccessPass(this));
         FPM.addPass(BPFPreserveDITypePass());
         MPM.addPass(createModuleToFunctionPassAdaptor(std::move(FPM)));
       });
   PB.registerPeepholeEPCallback([=](FunctionPassManager &FPM,
                                     PassBuilder::OptimizationLevel Level) {
     FPM.addPass(SimplifyCFGPass(SimplifyCFGOptions().hoistCommonInsts(true)));
   });
 }
 
 void BPFPassConfig::addIRPasses() {
   addPass(createBPFCheckAndAdjustIR());

llvm/tools/opt/NewPMDriver.cpp

PB.registerCGSCCOptimizerLateEPCallback(
         });
   if (tryParsePipelineText<FunctionPassManager>(PB, VectorizerStartEPPipeline))
     PB.registerVectorizerStartEPCallback(
         [&PB](FunctionPassManager &PM, PassBuilder::OptimizationLevel Level) {
           ExitOnError Err("Unable to parse VectorizerStartEP pipeline: ");
           Err(PB.parsePassPipeline(PM, VectorizerStartEPPipeline));
         });
   if (tryParsePipelineText<ModulePassManager>(PB, PipelineStartEPPipeline))
-    PB.registerPipelineStartEPCallback([&PB](ModulePassManager &PM) {
+    PB.registerPipelineStartEPCallback(
+        [&PB](ModulePassManager &PM, PassBuilder::OptimizationLevel) {
           ExitOnError Err("Unable to parse PipelineStartEP pipeline: ");
           Err(PB.parsePassPipeline(PM, PipelineStartEPPipeline));
         });
   if (tryParsePipelineText<FunctionPassManager>(PB, OptimizerLastEPPipeline))
     PB.registerOptimizerLastEPCallback(
         [&PB](ModulePassManager &PM, PassBuilder::OptimizationLevel) {
           ExitOnError Err("Unable to parse OptimizerLastEP pipeline: ");
           Err(PB.parsePassPipeline(PM, OptimizerLastEPPipeline));
         });
 }