1 //===- CoroCleanup.cpp - Coroutine Cleanup Pass ---------------------------===// 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/Coroutines/CoroCleanup.h" 10 #include "CoroInternal.h" 11 #include "llvm/IR/Function.h" 12 #include "llvm/IR/IRBuilder.h" 13 #include "llvm/IR/InstIterator.h" 14 #include "llvm/IR/Module.h" 15 #include "llvm/IR/PassManager.h" 16 #include "llvm/Transforms/Scalar/SimplifyCFG.h" 17 18 using namespace llvm; 19 20 #define DEBUG_TYPE "coro-cleanup" 21 22 namespace { 23 // Created on demand if CoroCleanup pass has work to do. 24 struct Lowerer : coro::LowererBase { 25 IRBuilder<> Builder; 26 Lowerer(Module &M) : LowererBase(M), Builder(Context) {} 27 bool lower(Function &F); 28 }; 29 } 30 31 static void lowerSubFn(IRBuilder<> &Builder, CoroSubFnInst *SubFn) { 32 Builder.SetInsertPoint(SubFn); 33 Value *FramePtr = SubFn->getFrame(); 34 int Index = SubFn->getIndex(); 35 36 auto *FrameTy = StructType::get(SubFn->getContext(), 37 {Builder.getPtrTy(), Builder.getPtrTy()}); 38 39 Builder.SetInsertPoint(SubFn); 40 auto *Gep = Builder.CreateConstInBoundsGEP2_32(FrameTy, FramePtr, 0, Index); 41 auto *Load = Builder.CreateLoad(FrameTy->getElementType(Index), Gep); 42 43 SubFn->replaceAllUsesWith(Load); 44 } 45 46 bool Lowerer::lower(Function &F) { 47 bool IsPrivateAndUnprocessed = F.isPresplitCoroutine() && F.hasLocalLinkage(); 48 bool Changed = false; 49 50 for (Instruction &I : llvm::make_early_inc_range(instructions(F))) { 51 if (auto *II = dyn_cast<IntrinsicInst>(&I)) { 52 switch (II->getIntrinsicID()) { 53 default: 54 continue; 55 case Intrinsic::coro_begin: 56 case Intrinsic::coro_begin_custom_abi: 57 II->replaceAllUsesWith(II->getArgOperand(1)); 58 break; 59 case Intrinsic::coro_free: 60 II->replaceAllUsesWith(II->getArgOperand(1)); 61 break; 62 case Intrinsic::coro_alloc: 63 II->replaceAllUsesWith(ConstantInt::getTrue(Context)); 64 break; 65 case Intrinsic::coro_async_resume: 66 II->replaceAllUsesWith( 67 ConstantPointerNull::get(cast<PointerType>(I.getType()))); 68 break; 69 case Intrinsic::coro_id: 70 case Intrinsic::coro_id_retcon: 71 case Intrinsic::coro_id_retcon_once: 72 case Intrinsic::coro_id_async: 73 II->replaceAllUsesWith(ConstantTokenNone::get(Context)); 74 break; 75 case Intrinsic::coro_subfn_addr: 76 lowerSubFn(Builder, cast<CoroSubFnInst>(II)); 77 break; 78 case Intrinsic::coro_end: 79 case Intrinsic::coro_suspend_retcon: 80 if (IsPrivateAndUnprocessed) { 81 II->replaceAllUsesWith(PoisonValue::get(II->getType())); 82 } else 83 continue; 84 break; 85 case Intrinsic::coro_async_size_replace: 86 auto *Target = cast<ConstantStruct>( 87 cast<GlobalVariable>(II->getArgOperand(0)->stripPointerCasts()) 88 ->getInitializer()); 89 auto *Source = cast<ConstantStruct>( 90 cast<GlobalVariable>(II->getArgOperand(1)->stripPointerCasts()) 91 ->getInitializer()); 92 auto *TargetSize = Target->getOperand(1); 93 auto *SourceSize = Source->getOperand(1); 94 if (TargetSize->isElementWiseEqual(SourceSize)) { 95 break; 96 } 97 auto *TargetRelativeFunOffset = Target->getOperand(0); 98 auto *NewFuncPtrStruct = ConstantStruct::get( 99 Target->getType(), TargetRelativeFunOffset, SourceSize); 100 Target->replaceAllUsesWith(NewFuncPtrStruct); 101 break; 102 } 103 II->eraseFromParent(); 104 Changed = true; 105 } 106 } 107 108 return Changed; 109 } 110 111 static bool declaresCoroCleanupIntrinsics(const Module &M) { 112 return coro::declaresIntrinsics( 113 M, {"llvm.coro.alloc", "llvm.coro.begin", "llvm.coro.subfn.addr", 114 "llvm.coro.free", "llvm.coro.id", "llvm.coro.id.retcon", 115 "llvm.coro.id.async", "llvm.coro.id.retcon.once", 116 "llvm.coro.async.size.replace", "llvm.coro.async.resume", 117 "llvm.coro.begin.custom.abi"}); 118 } 119 120 PreservedAnalyses CoroCleanupPass::run(Module &M, 121 ModuleAnalysisManager &MAM) { 122 if (!declaresCoroCleanupIntrinsics(M)) 123 return PreservedAnalyses::all(); 124 125 FunctionAnalysisManager &FAM = 126 MAM.getResult<FunctionAnalysisManagerModuleProxy>(M).getManager(); 127 128 FunctionPassManager FPM; 129 FPM.addPass(SimplifyCFGPass()); 130 131 PreservedAnalyses FuncPA; 132 FuncPA.preserveSet<CFGAnalyses>(); 133 134 Lowerer L(M); 135 for (auto &F : M) { 136 if (L.lower(F)) { 137 FAM.invalidate(F, FuncPA); 138 FPM.run(F, FAM); 139 } 140 } 141 142 return PreservedAnalyses::none(); 143 } 144