1 //===-- CGProfile.cpp -----------------------------------------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 #include "llvm/Transforms/Instrumentation/CGProfile.h" 10 11 #include "llvm/ADT/MapVector.h" 12 #include "llvm/Analysis/BlockFrequencyInfo.h" 13 #include "llvm/Analysis/LazyBlockFrequencyInfo.h" 14 #include "llvm/Analysis/TargetTransformInfo.h" 15 #include "llvm/IR/Constants.h" 16 #include "llvm/IR/MDBuilder.h" 17 #include "llvm/IR/PassManager.h" 18 #include "llvm/InitializePasses.h" 19 #include "llvm/ProfileData/InstrProf.h" 20 #include "llvm/Transforms/Instrumentation.h" 21 22 using namespace llvm; 23 24 static bool 25 addModuleFlags(Module &M, 26 MapVector<std::pair<Function *, Function *>, uint64_t> &Counts) { 27 if (Counts.empty()) 28 return false; 29 30 LLVMContext &Context = M.getContext(); 31 MDBuilder MDB(Context); 32 std::vector<Metadata *> Nodes; 33 34 for (auto E : Counts) { 35 Metadata *Vals[] = {ValueAsMetadata::get(E.first.first), 36 ValueAsMetadata::get(E.first.second), 37 MDB.createConstant(ConstantInt::get( 38 Type::getInt64Ty(Context), E.second))}; 39 Nodes.push_back(MDNode::get(Context, Vals)); 40 } 41 42 M.addModuleFlag(Module::Append, "CG Profile", 43 MDTuple::getDistinct(Context, Nodes)); 44 return true; 45 } 46 47 static bool runCGProfilePass( 48 Module &M, function_ref<BlockFrequencyInfo &(Function &)> GetBFI, 49 function_ref<TargetTransformInfo &(Function &)> GetTTI, bool LazyBFI) { 50 MapVector<std::pair<Function *, Function *>, uint64_t> Counts; 51 InstrProfSymtab Symtab; 52 auto UpdateCounts = [&](TargetTransformInfo &TTI, Function *F, 53 Function *CalledF, uint64_t NewCount) { 54 if (NewCount == 0) 55 return; 56 if (!CalledF || !TTI.isLoweredToCall(CalledF) || 57 CalledF->hasDLLImportStorageClass()) 58 return; 59 uint64_t &Count = Counts[std::make_pair(F, CalledF)]; 60 Count = SaturatingAdd(Count, NewCount); 61 }; 62 // Ignore error here. Indirect calls are ignored if this fails. 63 (void)(bool) Symtab.create(M); 64 for (auto &F : M) { 65 // Avoid extra cost of running passes for BFI when the function doesn't have 66 // entry count. Since LazyBlockFrequencyInfoPass only exists in LPM, check 67 // if using LazyBlockFrequencyInfoPass. 68 // TODO: Remove LazyBFI when LazyBlockFrequencyInfoPass is available in NPM. 69 if (F.isDeclaration() || (LazyBFI && !F.getEntryCount())) 70 continue; 71 auto &BFI = GetBFI(F); 72 if (BFI.getEntryFreq() == 0) 73 continue; 74 TargetTransformInfo &TTI = GetTTI(F); 75 for (auto &BB : F) { 76 Optional<uint64_t> BBCount = BFI.getBlockProfileCount(&BB); 77 if (!BBCount) 78 continue; 79 for (auto &I : BB) { 80 CallBase *CB = dyn_cast<CallBase>(&I); 81 if (!CB) 82 continue; 83 if (CB->isIndirectCall()) { 84 InstrProfValueData ValueData[8]; 85 uint32_t ActualNumValueData; 86 uint64_t TotalC; 87 if (!getValueProfDataFromInst(*CB, IPVK_IndirectCallTarget, 8, 88 ValueData, ActualNumValueData, TotalC)) 89 continue; 90 for (const auto &VD : 91 ArrayRef<InstrProfValueData>(ValueData, ActualNumValueData)) { 92 UpdateCounts(TTI, &F, Symtab.getFunction(VD.Value), VD.Count); 93 } 94 continue; 95 } 96 UpdateCounts(TTI, &F, CB->getCalledFunction(), *BBCount); 97 } 98 } 99 } 100 101 return addModuleFlags(M, Counts); 102 } 103 104 PreservedAnalyses CGProfilePass::run(Module &M, ModuleAnalysisManager &MAM) { 105 FunctionAnalysisManager &FAM = 106 MAM.getResult<FunctionAnalysisManagerModuleProxy>(M).getManager(); 107 auto GetBFI = [&FAM](Function &F) -> BlockFrequencyInfo & { 108 return FAM.getResult<BlockFrequencyAnalysis>(F); 109 }; 110 auto GetTTI = [&FAM](Function &F) -> TargetTransformInfo & { 111 return FAM.getResult<TargetIRAnalysis>(F); 112 }; 113 114 runCGProfilePass(M, GetBFI, GetTTI, false); 115 116 return PreservedAnalyses::all(); 117 } 118