Index: include/llvm/Transforms/IPO/PassManagerBuilder.h =================================================================== --- include/llvm/Transforms/IPO/PassManagerBuilder.h +++ include/llvm/Transforms/IPO/PassManagerBuilder.h @@ -133,6 +133,8 @@ bool VerifyOutput; bool MergeFunctions; bool PrepareForLTO; + bool PrepareForThinLTO; + bool PerformThinLTO; /// Profile data file name that the instrumentation will be written to. std::string PGOInstrGen; @@ -160,6 +162,7 @@ void addEarlyLTOOptimizationPasses(legacy::PassManagerBase &PM); void addLateLTOOptimizationPasses(legacy::PassManagerBase &PM); void addPGOInstrPasses(legacy::PassManagerBase &MPM); + void addFunctionSimplificationPasses(legacy::PassManagerBase &MPM); public: /// populateFunctionPassManager - This fills in the function pass manager, @@ -170,6 +173,7 @@ /// populateModulePassManager - This sets up the primary pass manager. void populateModulePassManager(legacy::PassManagerBase &MPM); void populateLTOPassManager(legacy::PassManagerBase &PM); + void populateThinLTOPassManager(legacy::PassManagerBase &PM); }; /// Registers a function for adding a standard set of passes. This should be Index: lib/Transforms/IPO/PassManagerBuilder.cpp =================================================================== --- lib/Transforms/IPO/PassManagerBuilder.cpp +++ lib/Transforms/IPO/PassManagerBuilder.cpp @@ -140,6 +140,8 @@ PrepareForLTO = false; PGOInstrGen = RunPGOInstrGen; PGOInstrUse = RunPGOInstrUse; + PrepareForThinLTO = false; + PerformThinLTO = false; } PassManagerBuilder::~PassManagerBuilder() { @@ -216,78 +218,8 @@ MPM.add(createPGOInstrumentationUsePass(PGOInstrUse)); } -void PassManagerBuilder::populateModulePassManager( +void PassManagerBuilder::addFunctionSimplificationPasses( legacy::PassManagerBase &MPM) { - // Allow forcing function attributes as a debugging and tuning aid. - MPM.add(createForceFunctionAttrsLegacyPass()); - - // If all optimizations are disabled, just run the always-inline pass and, - // if enabled, the function merging pass. - if (OptLevel == 0) { - addPGOInstrPasses(MPM); - if (Inliner) { - MPM.add(Inliner); - Inliner = nullptr; - } - - // FIXME: The BarrierNoopPass is a HACK! The inliner pass above implicitly - // creates a CGSCC pass manager, but we don't want to add extensions into - // that pass manager. To prevent this we insert a no-op module pass to reset - // the pass manager to get the same behavior as EP_OptimizerLast in non-O0 - // builds. The function merging pass is - if (MergeFunctions) - MPM.add(createMergeFunctionsPass()); - else if (!GlobalExtensions->empty() || !Extensions.empty()) - MPM.add(createBarrierNoopPass()); - - addExtensionsToPM(EP_EnabledOnOptLevel0, MPM); - return; - } - - // Add LibraryInfo if we have some. - if (LibraryInfo) - MPM.add(new TargetLibraryInfoWrapperPass(*LibraryInfo)); - - addInitialAliasAnalysisPasses(MPM); - - if (!DisableUnitAtATime) { - // Infer attributes about declarations if possible. - MPM.add(createInferFunctionAttrsLegacyPass()); - - addExtensionsToPM(EP_ModuleOptimizerEarly, MPM); - - MPM.add(createIPSCCPPass()); // IP SCCP - MPM.add(createGlobalOptimizerPass()); // Optimize out global vars - // Promote any localized global vars - MPM.add(createPromoteMemoryToRegisterPass()); - - MPM.add(createDeadArgEliminationPass()); // Dead argument elimination - - MPM.add(createInstructionCombiningPass());// Clean up after IPCP & DAE - addExtensionsToPM(EP_Peephole, MPM); - MPM.add(createCFGSimplificationPass()); // Clean up after IPCP & DAE - } - - addPGOInstrPasses(MPM); - - if (EnableNonLTOGlobalsModRef) - // We add a module alias analysis pass here. In part due to bugs in the - // analysis infrastructure this "works" in that the analysis stays alive - // for the entire SCC pass run below. - MPM.add(createGlobalsAAWrapperPass()); - - // Start of CallGraph SCC passes. - if (!DisableUnitAtATime) - MPM.add(createPruneEHPass()); // Remove dead EH info - if (Inliner) { - MPM.add(Inliner); - Inliner = nullptr; - } - if (!DisableUnitAtATime) - MPM.add(createPostOrderFunctionAttrsPass()); - if (OptLevel > 2) - MPM.add(createArgumentPromotionPass()); // Scalarize uninlined fn args - // Start of function pass. // Break up aggregate allocas, using SSAUpdater. if (UseNewSROA) @@ -304,6 +236,11 @@ MPM.add(createTailCallEliminationPass()); // Eliminate tail calls MPM.add(createCFGSimplificationPass()); // Merge & remove BBs MPM.add(createReassociatePass()); // Reassociate expressions + if (PrepareForThinLTO) { + MPM.add(createAggressiveDCEPass()); // Delete dead instructions + MPM.add(createInstructionCombiningPass()); // Combine silly seq's + return; + } // Rotate Loop - disable header duplication at -Oz MPM.add(createLoopRotatePass(SizeLevel == 2 ? 0 : -1)); MPM.add(createLICMPass()); // Hoist loop invariants @@ -373,6 +310,93 @@ MPM.add(createCFGSimplificationPass()); // Merge & remove BBs MPM.add(createInstructionCombiningPass()); // Clean up after everything. addExtensionsToPM(EP_Peephole, MPM); +} + +void PassManagerBuilder::populateModulePassManager( + legacy::PassManagerBase &MPM) { + // Allow forcing function attributes as a debugging and tuning aid. + MPM.add(createForceFunctionAttrsLegacyPass()); + + // If all optimizations are disabled, just run the always-inline pass and, + // if enabled, the function merging pass. + if (OptLevel == 0) { + addPGOInstrPasses(MPM); + if (Inliner) { + MPM.add(Inliner); + Inliner = nullptr; + } + + // FIXME: The BarrierNoopPass is a HACK! The inliner pass above implicitly + // creates a CGSCC pass manager, but we don't want to add extensions into + // that pass manager. To prevent this we insert a no-op module pass to reset + // the pass manager to get the same behavior as EP_OptimizerLast in non-O0 + // builds. The function merging pass is + if (MergeFunctions) + MPM.add(createMergeFunctionsPass()); + else if (!GlobalExtensions->empty() || !Extensions.empty()) + MPM.add(createBarrierNoopPass()); + + addExtensionsToPM(EP_EnabledOnOptLevel0, MPM); + return; + } + + // Add LibraryInfo if we have some. + if (LibraryInfo) + MPM.add(new TargetLibraryInfoWrapperPass(*LibraryInfo)); + + addInitialAliasAnalysisPasses(MPM); + + if (!DisableUnitAtATime) { + // Infer attributes about declarations if possible. + MPM.add(createInferFunctionAttrsLegacyPass()); + + addExtensionsToPM(EP_ModuleOptimizerEarly, MPM); + + MPM.add(createIPSCCPPass()); // IP SCCP + MPM.add(createGlobalOptimizerPass()); // Optimize out global vars + + if (PerformThinLTO) + // Linking modules together can lead to duplicated global constants, only + // keep one copy of each constant. + MPM.add(createConstantMergePass()); + + // Promote any localized global vars + MPM.add(createPromoteMemoryToRegisterPass()); + + MPM.add(createDeadArgEliminationPass()); // Dead argument elimination + + MPM.add(createInstructionCombiningPass()); // Clean up after IPCP & DAE + addExtensionsToPM(EP_Peephole, MPM); + MPM.add(createCFGSimplificationPass()); // Clean up after IPCP & DAE + } + + addPGOInstrPasses(MPM); + + if (EnableNonLTOGlobalsModRef) + // We add a module alias analysis pass here. In part due to bugs in the + // analysis infrastructure this "works" in that the analysis stays alive + // for the entire SCC pass run below. + MPM.add(createGlobalsAAWrapperPass()); + + // Start of CallGraph SCC passes. + if (!DisableUnitAtATime) + MPM.add(createPruneEHPass()); // Remove dead EH info + if (Inliner) { + MPM.add(Inliner); + Inliner = nullptr; + } + if (!DisableUnitAtATime) + MPM.add(createPostOrderFunctionAttrsPass()); + if (OptLevel > 2) + MPM.add(createArgumentPromotionPass()); // Scalarize uninlined fn args + + addFunctionSimplificationPasses(MPM); + + // If we are planning to perform THinLTO later, let's not bloat the code with + // unrolling/vectorization/... now. We'll first run the inliner + CGSCC passes + // during ThinLTO and performs the rest of the optimizations afterward. + if (PrepareForThinLTO) + return; // FIXME: This is a HACK! The inliner pass above implicitly creates a CGSCC // pass manager that we are specifically trying to avoid. To prevent this @@ -392,7 +416,7 @@ if (!DisableUnitAtATime) MPM.add(createReversePostOrderFunctionAttrsPass()); - if (!DisableUnitAtATime && OptLevel > 1 && !PrepareForLTO) { + if (!DisableUnitAtATime && OptLevel > 1 && !PrepareForLTO) // Remove avail extern fns and globals definitions if we aren't // compiling an object file for later LTO. For LTO we want to preserve // these so they are eligible for inlining at link-time. Note if they @@ -403,6 +427,15 @@ // globals referenced by available external functions dead // and saves running remaining passes on the eliminated functions. MPM.add(createEliminateAvailableExternallyPass()); + + if (PerformThinLTO) { + // Remove dead fns and globals. Removing unreferenced functions could lead + // to more opportunities for globalopt + MPM.add(createGlobalDCEPass()); + MPM.add(createGlobalOptimizerPass()); + // Remove dead fns and globals after globalopt + MPM.add(createGlobalDCEPass()); + addFunctionSimplificationPasses(MPM); } if (EnableNonLTOGlobalsModRef) @@ -678,6 +711,20 @@ PM.add(createMergeFunctionsPass()); } +void PassManagerBuilder::populateThinLTOPassManager( + legacy::PassManagerBase &PM) { + PerformThinLTO = true; + + if (VerifyInput) + PM.add(createVerifierPass()); + + populateModulePassManager(PM); + + if (VerifyOutput) + PM.add(createVerifierPass()); + PerformThinLTO = false; +} + void PassManagerBuilder::populateLTOPassManager(legacy::PassManagerBase &PM) { if (LibraryInfo) PM.add(new TargetLibraryInfoWrapperPass(*LibraryInfo));