1 //===- AMDGPUAnnotateKernelFeaturesPass.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 /// \file This pass propagates the uniform-work-group-size attribute from 10 /// kernels to leaf functions when possible. It also adds additional attributes 11 /// to hint ABI lowering optimizations later. 12 // 13 //===----------------------------------------------------------------------===// 14 15 #include "AMDGPU.h" 16 #include "GCNSubtarget.h" 17 #include "llvm/Analysis/CallGraph.h" 18 #include "llvm/Analysis/CallGraphSCCPass.h" 19 #include "llvm/CodeGen/TargetPassConfig.h" 20 #include "llvm/IR/IntrinsicsAMDGPU.h" 21 #include "llvm/IR/IntrinsicsR600.h" 22 #include "llvm/Target/TargetMachine.h" 23 24 #define DEBUG_TYPE "amdgpu-annotate-kernel-features" 25 26 using namespace llvm; 27 28 namespace { 29 class AMDGPUAnnotateKernelFeatures : public CallGraphSCCPass { 30 private: 31 const TargetMachine *TM = nullptr; 32 33 bool addFeatureAttributes(Function &F); 34 35 public: 36 static char ID; 37 38 AMDGPUAnnotateKernelFeatures() : CallGraphSCCPass(ID) {} 39 40 bool doInitialization(CallGraph &CG) override; 41 bool runOnSCC(CallGraphSCC &SCC) override; 42 43 StringRef getPassName() const override { 44 return "AMDGPU Annotate Kernel Features"; 45 } 46 47 void getAnalysisUsage(AnalysisUsage &AU) const override { 48 AU.setPreservesAll(); 49 CallGraphSCCPass::getAnalysisUsage(AU); 50 } 51 }; 52 53 } // end anonymous namespace 54 55 char AMDGPUAnnotateKernelFeatures::ID = 0; 56 57 char &llvm::AMDGPUAnnotateKernelFeaturesID = AMDGPUAnnotateKernelFeatures::ID; 58 59 INITIALIZE_PASS(AMDGPUAnnotateKernelFeatures, DEBUG_TYPE, 60 "Add AMDGPU function attributes", false, false) 61 62 bool AMDGPUAnnotateKernelFeatures::addFeatureAttributes(Function &F) { 63 bool HaveStackObjects = false; 64 bool Changed = false; 65 bool HaveCall = false; 66 bool IsFunc = !AMDGPU::isEntryFunctionCC(F.getCallingConv()); 67 68 for (BasicBlock &BB : F) { 69 for (Instruction &I : BB) { 70 if (isa<AllocaInst>(I)) { 71 HaveStackObjects = true; 72 continue; 73 } 74 75 if (auto *CB = dyn_cast<CallBase>(&I)) { 76 const Function *Callee = 77 dyn_cast<Function>(CB->getCalledOperand()->stripPointerCasts()); 78 79 // Note the occurrence of indirect call. 80 if (!Callee) { 81 if (!CB->isInlineAsm()) 82 HaveCall = true; 83 84 continue; 85 } 86 87 Intrinsic::ID IID = Callee->getIntrinsicID(); 88 if (IID == Intrinsic::not_intrinsic) { 89 HaveCall = true; 90 Changed = true; 91 } 92 } 93 } 94 } 95 96 // TODO: We could refine this to captured pointers that could possibly be 97 // accessed by flat instructions. For now this is mostly a poor way of 98 // estimating whether there are calls before argument lowering. 99 if (!IsFunc && HaveCall) { 100 F.addFnAttr("amdgpu-calls"); 101 Changed = true; 102 } 103 104 if (HaveStackObjects) { 105 F.addFnAttr("amdgpu-stack-objects"); 106 Changed = true; 107 } 108 109 return Changed; 110 } 111 112 bool AMDGPUAnnotateKernelFeatures::runOnSCC(CallGraphSCC &SCC) { 113 bool Changed = false; 114 115 for (CallGraphNode *I : SCC) { 116 Function *F = I->getFunction(); 117 // Ignore functions with graphics calling conventions, these are currently 118 // not allowed to have kernel arguments. 119 if (!F || F->isDeclaration() || AMDGPU::isGraphics(F->getCallingConv())) 120 continue; 121 // Add feature attributes 122 Changed |= addFeatureAttributes(*F); 123 } 124 125 return Changed; 126 } 127 128 bool AMDGPUAnnotateKernelFeatures::doInitialization(CallGraph &CG) { 129 auto *TPC = getAnalysisIfAvailable<TargetPassConfig>(); 130 if (!TPC) 131 report_fatal_error("TargetMachine is required"); 132 133 TM = &TPC->getTM<TargetMachine>(); 134 return false; 135 } 136 137 Pass *llvm::createAMDGPUAnnotateKernelFeaturesPass() { 138 return new AMDGPUAnnotateKernelFeatures(); 139 } 140