1 //=- WebAssemblyMachineFunctionInfo.cpp - WebAssembly Machine Function Info -=// 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 10 /// This file implements WebAssembly-specific per-machine-function 11 /// information. 12 /// 13 //===----------------------------------------------------------------------===// 14 15 #include "WebAssemblyMachineFunctionInfo.h" 16 #include "MCTargetDesc/WebAssemblyInstPrinter.h" 17 #include "Utils/WebAssemblyTypeUtilities.h" 18 #include "WebAssemblyISelLowering.h" 19 #include "WebAssemblySubtarget.h" 20 #include "llvm/CodeGen/Analysis.h" 21 #include "llvm/CodeGen/WasmEHFuncInfo.h" 22 #include "llvm/Target/TargetMachine.h" 23 using namespace llvm; 24 25 WebAssemblyFunctionInfo::~WebAssemblyFunctionInfo() = default; // anchor. 26 27 void WebAssemblyFunctionInfo::initWARegs(MachineRegisterInfo &MRI) { 28 assert(WARegs.empty()); 29 unsigned Reg = UnusedReg; 30 WARegs.resize(MRI.getNumVirtRegs(), Reg); 31 } 32 33 void llvm::computeLegalValueVTs(const Function &F, const TargetMachine &TM, 34 Type *Ty, SmallVectorImpl<MVT> &ValueVTs) { 35 const DataLayout &DL(F.getParent()->getDataLayout()); 36 const WebAssemblyTargetLowering &TLI = 37 *TM.getSubtarget<WebAssemblySubtarget>(F).getTargetLowering(); 38 SmallVector<EVT, 4> VTs; 39 ComputeValueVTs(TLI, DL, Ty, VTs); 40 41 for (EVT VT : VTs) { 42 unsigned NumRegs = TLI.getNumRegisters(F.getContext(), VT); 43 MVT RegisterVT = TLI.getRegisterType(F.getContext(), VT); 44 for (unsigned I = 0; I != NumRegs; ++I) 45 ValueVTs.push_back(RegisterVT); 46 } 47 } 48 49 void llvm::computeSignatureVTs(const FunctionType *Ty, 50 const Function *TargetFunc, 51 const Function &ContextFunc, 52 const TargetMachine &TM, 53 SmallVectorImpl<MVT> &Params, 54 SmallVectorImpl<MVT> &Results) { 55 computeLegalValueVTs(ContextFunc, TM, Ty->getReturnType(), Results); 56 57 MVT PtrVT = MVT::getIntegerVT(TM.createDataLayout().getPointerSizeInBits()); 58 if (Results.size() > 1 && 59 !TM.getSubtarget<WebAssemblySubtarget>(ContextFunc).hasMultivalue()) { 60 // WebAssembly can't lower returns of multiple values without demoting to 61 // sret unless multivalue is enabled (see 62 // WebAssemblyTargetLowering::CanLowerReturn). So replace multiple return 63 // values with a poitner parameter. 64 Results.clear(); 65 Params.push_back(PtrVT); 66 } 67 68 for (auto *Param : Ty->params()) 69 computeLegalValueVTs(ContextFunc, TM, Param, Params); 70 if (Ty->isVarArg()) 71 Params.push_back(PtrVT); 72 73 // For swiftcc, emit additional swiftself and swifterror parameters 74 // if there aren't. These additional parameters are also passed for caller. 75 // They are necessary to match callee and caller signature for indirect 76 // call. 77 78 if (TargetFunc && TargetFunc->getCallingConv() == CallingConv::Swift) { 79 MVT PtrVT = MVT::getIntegerVT(TM.createDataLayout().getPointerSizeInBits()); 80 bool HasSwiftErrorArg = false; 81 bool HasSwiftSelfArg = false; 82 for (const auto &Arg : TargetFunc->args()) { 83 HasSwiftErrorArg |= Arg.hasAttribute(Attribute::SwiftError); 84 HasSwiftSelfArg |= Arg.hasAttribute(Attribute::SwiftSelf); 85 } 86 if (!HasSwiftErrorArg) 87 Params.push_back(PtrVT); 88 if (!HasSwiftSelfArg) 89 Params.push_back(PtrVT); 90 } 91 } 92 93 void llvm::valTypesFromMVTs(const ArrayRef<MVT> &In, 94 SmallVectorImpl<wasm::ValType> &Out) { 95 for (MVT Ty : In) 96 Out.push_back(WebAssembly::toValType(Ty)); 97 } 98 99 std::unique_ptr<wasm::WasmSignature> 100 llvm::signatureFromMVTs(const SmallVectorImpl<MVT> &Results, 101 const SmallVectorImpl<MVT> &Params) { 102 auto Sig = std::make_unique<wasm::WasmSignature>(); 103 valTypesFromMVTs(Results, Sig->Returns); 104 valTypesFromMVTs(Params, Sig->Params); 105 return Sig; 106 } 107 108 yaml::WebAssemblyFunctionInfo::WebAssemblyFunctionInfo( 109 const llvm::WebAssemblyFunctionInfo &MFI) 110 : CFGStackified(MFI.isCFGStackified()) { 111 auto *EHInfo = MFI.getWasmEHFuncInfo(); 112 const llvm::MachineFunction &MF = MFI.getMachineFunction(); 113 114 for (auto VT : MFI.getParams()) 115 Params.push_back(EVT(VT).getEVTString()); 116 for (auto VT : MFI.getResults()) 117 Results.push_back(EVT(VT).getEVTString()); 118 119 // MFI.getWasmEHFuncInfo() is non-null only for functions with the 120 // personality function. 121 if (EHInfo) { 122 // SrcToUnwindDest can contain stale mappings in case BBs are removed in 123 // optimizations, in case, for example, they are unreachable. We should not 124 // include their info. 125 SmallPtrSet<const MachineBasicBlock *, 16> MBBs; 126 for (const auto &MBB : MF) 127 MBBs.insert(&MBB); 128 for (auto KV : EHInfo->SrcToUnwindDest) { 129 auto *SrcBB = KV.first.get<MachineBasicBlock *>(); 130 auto *DestBB = KV.second.get<MachineBasicBlock *>(); 131 if (MBBs.count(SrcBB) && MBBs.count(DestBB)) 132 SrcToUnwindDest[SrcBB->getNumber()] = DestBB->getNumber(); 133 } 134 } 135 } 136 137 void yaml::WebAssemblyFunctionInfo::mappingImpl(yaml::IO &YamlIO) { 138 MappingTraits<WebAssemblyFunctionInfo>::mapping(YamlIO, *this); 139 } 140 141 void WebAssemblyFunctionInfo::initializeBaseYamlFields( 142 const yaml::WebAssemblyFunctionInfo &YamlMFI) { 143 CFGStackified = YamlMFI.CFGStackified; 144 for (auto VT : YamlMFI.Params) 145 addParam(WebAssembly::parseMVT(VT.Value)); 146 for (auto VT : YamlMFI.Results) 147 addResult(WebAssembly::parseMVT(VT.Value)); 148 if (WasmEHInfo) { 149 for (auto KV : YamlMFI.SrcToUnwindDest) 150 WasmEHInfo->setUnwindDest(MF.getBlockNumbered(KV.first), 151 MF.getBlockNumbered(KV.second)); 152 } 153 } 154