1 //===- InjectTLIMAppings.cpp - TLI to VFABI attribute injection ----------===// 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 // Populates the VFABI attribute with the scalar-to-vector mappings 10 // from the TargetLibraryInfo. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #include "llvm/Transforms/Utils/InjectTLIMappings.h" 15 #include "llvm/ADT/Statistic.h" 16 #include "llvm/Analysis/DemandedBits.h" 17 #include "llvm/Analysis/GlobalsModRef.h" 18 #include "llvm/Analysis/OptimizationRemarkEmitter.h" 19 #include "llvm/Analysis/TargetLibraryInfo.h" 20 #include "llvm/Analysis/VectorUtils.h" 21 #include "llvm/IR/InstIterator.h" 22 #include "llvm/IR/IntrinsicInst.h" 23 #include "llvm/Transforms/Utils.h" 24 #include "llvm/Transforms/Utils/ModuleUtils.h" 25 26 using namespace llvm; 27 28 #define DEBUG_TYPE "inject-tli-mappings" 29 30 STATISTIC(NumCallInjected, 31 "Number of calls in which the mappings have been injected."); 32 33 STATISTIC(NumVFDeclAdded, 34 "Number of function declarations that have been added."); 35 STATISTIC(NumCompUsedAdded, 36 "Number of `@llvm.compiler.used` operands that have been added."); 37 38 /// A helper function that adds the vector function declaration that 39 /// vectorizes the CallInst CI with a vectorization factor of VF 40 /// lanes. The TLI assumes that all parameters and the return type of 41 /// CI (other than void) need to be widened to a VectorType of VF 42 /// lanes. 43 static void addVariantDeclaration(CallInst &CI, const unsigned VF, 44 const StringRef VFName) { 45 Module *M = CI.getModule(); 46 47 // Add function declaration. 48 Type *RetTy = ToVectorTy(CI.getType(), VF); 49 SmallVector<Type *, 4> Tys; 50 for (Value *ArgOperand : CI.arg_operands()) 51 Tys.push_back(ToVectorTy(ArgOperand->getType(), VF)); 52 assert(!CI.getFunctionType()->isVarArg() && 53 "VarArg functions are not supported."); 54 FunctionType *FTy = FunctionType::get(RetTy, Tys, /*isVarArg=*/false); 55 Function *VectorF = 56 Function::Create(FTy, Function::ExternalLinkage, VFName, M); 57 VectorF->copyAttributesFrom(CI.getCalledFunction()); 58 ++NumVFDeclAdded; 59 LLVM_DEBUG(dbgs() << DEBUG_TYPE << ": Added to the module: `" << VFName 60 << "` of type " << *(VectorF->getType()) << "\n"); 61 62 // Make function declaration (without a body) "sticky" in the IR by 63 // listing it in the @llvm.compiler.used intrinsic. 64 assert(!VectorF->size() && "VFABI attribute requires `@llvm.compiler.used` " 65 "only on declarations."); 66 appendToCompilerUsed(*M, {VectorF}); 67 LLVM_DEBUG(dbgs() << DEBUG_TYPE << ": Adding `" << VFName 68 << "` to `@llvm.compiler.used`.\n"); 69 ++NumCompUsedAdded; 70 } 71 72 static void addMappingsFromTLI(const TargetLibraryInfo &TLI, CallInst &CI) { 73 // This is needed to make sure we don't query the TLI for calls to 74 // bitcast of function pointers, like `%call = call i32 (i32*, ...) 75 // bitcast (i32 (...)* @goo to i32 (i32*, ...)*)(i32* nonnull %i)`, 76 // as such calls make the `isFunctionVectorizable` raise an 77 // exception. 78 if (CI.isNoBuiltin() || !CI.getCalledFunction()) 79 return; 80 81 StringRef ScalarName = CI.getCalledFunction()->getName(); 82 83 // Nothing to be done if the TLI thinks the function is not 84 // vectorizable. 85 if (!TLI.isFunctionVectorizable(ScalarName)) 86 return; 87 SmallVector<std::string, 8> Mappings; 88 VFABI::getVectorVariantNames(CI, Mappings); 89 Module *M = CI.getModule(); 90 const SetVector<StringRef> OriginalSetOfMappings(Mappings.begin(), 91 Mappings.end()); 92 // All VFs in the TLI are powers of 2. 93 for (unsigned VF = 2, WidestVF = TLI.getWidestVF(ScalarName); VF <= WidestVF; 94 VF *= 2) { 95 const std::string TLIName = 96 std::string(TLI.getVectorizedFunction(ScalarName, VF)); 97 if (!TLIName.empty()) { 98 std::string MangledName = VFABI::mangleTLIVectorName( 99 TLIName, ScalarName, CI.getNumArgOperands(), VF); 100 if (!OriginalSetOfMappings.count(MangledName)) { 101 Mappings.push_back(MangledName); 102 ++NumCallInjected; 103 } 104 Function *VariantF = M->getFunction(TLIName); 105 if (!VariantF) 106 addVariantDeclaration(CI, VF, TLIName); 107 } 108 } 109 110 VFABI::setVectorVariantNames(&CI, Mappings); 111 } 112 113 static bool runImpl(const TargetLibraryInfo &TLI, Function &F) { 114 for (auto &I : instructions(F)) 115 if (auto CI = dyn_cast<CallInst>(&I)) 116 addMappingsFromTLI(TLI, *CI); 117 // Even if the pass adds IR attributes, the analyses are preserved. 118 return false; 119 } 120 121 //////////////////////////////////////////////////////////////////////////////// 122 // New pass manager implementation. 123 //////////////////////////////////////////////////////////////////////////////// 124 PreservedAnalyses InjectTLIMappings::run(Function &F, 125 FunctionAnalysisManager &AM) { 126 const TargetLibraryInfo &TLI = AM.getResult<TargetLibraryAnalysis>(F); 127 runImpl(TLI, F); 128 // Even if the pass adds IR attributes, the analyses are preserved. 129 return PreservedAnalyses::all(); 130 } 131 132 //////////////////////////////////////////////////////////////////////////////// 133 // Legacy PM Implementation. 134 //////////////////////////////////////////////////////////////////////////////// 135 bool InjectTLIMappingsLegacy::runOnFunction(Function &F) { 136 const TargetLibraryInfo &TLI = 137 getAnalysis<TargetLibraryInfoWrapperPass>().getTLI(F); 138 return runImpl(TLI, F); 139 } 140 141 void InjectTLIMappingsLegacy::getAnalysisUsage(AnalysisUsage &AU) const { 142 AU.setPreservesCFG(); 143 AU.addRequired<TargetLibraryInfoWrapperPass>(); 144 AU.addPreserved<TargetLibraryInfoWrapperPass>(); 145 AU.addPreserved<ScalarEvolutionWrapperPass>(); 146 AU.addPreserved<AAResultsWrapperPass>(); 147 AU.addPreserved<LoopAccessLegacyAnalysis>(); 148 AU.addPreserved<DemandedBitsWrapperPass>(); 149 AU.addPreserved<OptimizationRemarkEmitterWrapperPass>(); 150 AU.addPreserved<GlobalsAAWrapperPass>(); 151 } 152 153 //////////////////////////////////////////////////////////////////////////////// 154 // Legacy Pass manager initialization 155 //////////////////////////////////////////////////////////////////////////////// 156 char InjectTLIMappingsLegacy::ID = 0; 157 158 INITIALIZE_PASS_BEGIN(InjectTLIMappingsLegacy, DEBUG_TYPE, 159 "Inject TLI Mappings", false, false) 160 INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass) 161 INITIALIZE_PASS_END(InjectTLIMappingsLegacy, DEBUG_TYPE, "Inject TLI Mappings", 162 false, false) 163 164 FunctionPass *llvm::createInjectTLIMappingsLegacyPass() { 165 return new InjectTLIMappingsLegacy(); 166 } 167