1 //===-- PowerPCSubtarget.cpp - PPC Subtarget Information ------------------===// 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 // This file implements the PPC specific subclass of TargetSubtargetInfo. 10 // 11 //===----------------------------------------------------------------------===// 12 13 #include "PPCSubtarget.h" 14 #include "PPC.h" 15 #include "PPCRegisterInfo.h" 16 #include "PPCTargetMachine.h" 17 #include "llvm/CodeGen/MachineFunction.h" 18 #include "llvm/CodeGen/MachineScheduler.h" 19 #include "llvm/IR/Attributes.h" 20 #include "llvm/IR/Function.h" 21 #include "llvm/IR/GlobalValue.h" 22 #include "llvm/Support/CommandLine.h" 23 #include "llvm/Support/TargetRegistry.h" 24 #include "llvm/Target/TargetMachine.h" 25 #include <cstdlib> 26 27 using namespace llvm; 28 29 #define DEBUG_TYPE "ppc-subtarget" 30 31 #define GET_SUBTARGETINFO_TARGET_DESC 32 #define GET_SUBTARGETINFO_CTOR 33 #include "PPCGenSubtargetInfo.inc" 34 35 static cl::opt<bool> UseSubRegLiveness("ppc-track-subreg-liveness", 36 cl::desc("Enable subregister liveness tracking for PPC"), cl::Hidden); 37 38 static cl::opt<bool> 39 EnableMachinePipeliner("ppc-enable-pipeliner", 40 cl::desc("Enable Machine Pipeliner for PPC"), 41 cl::init(false), cl::Hidden); 42 43 PPCSubtarget &PPCSubtarget::initializeSubtargetDependencies(StringRef CPU, 44 StringRef FS) { 45 initializeEnvironment(); 46 initSubtargetFeatures(CPU, FS); 47 return *this; 48 } 49 50 PPCSubtarget::PPCSubtarget(const Triple &TT, const std::string &CPU, 51 const std::string &FS, const PPCTargetMachine &TM) 52 : PPCGenSubtargetInfo(TT, CPU, /*TuneCPU*/ CPU, FS), TargetTriple(TT), 53 IsPPC64(TargetTriple.getArch() == Triple::ppc64 || 54 TargetTriple.getArch() == Triple::ppc64le), 55 TM(TM), FrameLowering(initializeSubtargetDependencies(CPU, FS)), 56 InstrInfo(*this), TLInfo(TM, *this) {} 57 58 void PPCSubtarget::initializeEnvironment() { 59 StackAlignment = Align(16); 60 CPUDirective = PPC::DIR_NONE; 61 HasMFOCRF = false; 62 Has64BitSupport = false; 63 Use64BitRegs = false; 64 UseCRBits = false; 65 HasHardFloat = false; 66 HasAltivec = false; 67 HasSPE = false; 68 HasFPU = false; 69 HasVSX = false; 70 NeedsTwoConstNR = false; 71 HasP8Vector = false; 72 HasP8Altivec = false; 73 HasP8Crypto = false; 74 HasP9Vector = false; 75 HasP9Altivec = false; 76 HasMMA = false; 77 HasP10Vector = false; 78 HasPrefixInstrs = false; 79 HasPCRelativeMemops = false; 80 HasFCPSGN = false; 81 HasFSQRT = false; 82 HasFRE = false; 83 HasFRES = false; 84 HasFRSQRTE = false; 85 HasFRSQRTES = false; 86 HasRecipPrec = false; 87 HasSTFIWX = false; 88 HasLFIWAX = false; 89 HasFPRND = false; 90 HasFPCVT = false; 91 HasISEL = false; 92 HasBPERMD = false; 93 HasExtDiv = false; 94 HasCMPB = false; 95 HasLDBRX = false; 96 IsBookE = false; 97 HasOnlyMSYNC = false; 98 IsPPC4xx = false; 99 IsPPC6xx = false; 100 IsE500 = false; 101 FeatureMFTB = false; 102 AllowsUnalignedFPAccess = false; 103 DeprecatedDST = false; 104 HasICBT = false; 105 HasInvariantFunctionDescriptors = false; 106 HasPartwordAtomics = false; 107 HasDirectMove = false; 108 HasHTM = false; 109 HasFloat128 = false; 110 HasFusion = false; 111 HasAddiLoadFusion = false; 112 HasAddisLoadFusion = false; 113 IsISA3_0 = false; 114 IsISA3_1 = false; 115 UseLongCalls = false; 116 SecurePlt = false; 117 VectorsUseTwoUnits = false; 118 UsePPCPreRASchedStrategy = false; 119 UsePPCPostRASchedStrategy = false; 120 PairedVectorMemops = false; 121 PredictableSelectIsExpensive = false; 122 123 HasPOPCNTD = POPCNTD_Unavailable; 124 } 125 126 void PPCSubtarget::initSubtargetFeatures(StringRef CPU, StringRef FS) { 127 // Determine default and user specified characteristics 128 std::string CPUName = std::string(CPU); 129 if (CPUName.empty() || CPU == "generic") { 130 // If cross-compiling with -march=ppc64le without -mcpu 131 if (TargetTriple.getArch() == Triple::ppc64le) 132 CPUName = "ppc64le"; 133 else if (TargetTriple.getSubArch() == Triple::PPCSubArch_spe) 134 CPUName = "e500"; 135 else 136 CPUName = "generic"; 137 } 138 139 // Initialize scheduling itinerary for the specified CPU. 140 InstrItins = getInstrItineraryForCPU(CPUName); 141 142 // Parse features string. 143 ParseSubtargetFeatures(CPUName, /*TuneCPU*/ CPUName, FS); 144 145 // If the user requested use of 64-bit regs, but the cpu selected doesn't 146 // support it, ignore. 147 if (IsPPC64 && has64BitSupport()) 148 Use64BitRegs = true; 149 150 if ((TargetTriple.isOSFreeBSD() && TargetTriple.getOSMajorVersion() >= 13) || 151 TargetTriple.isOSNetBSD() || TargetTriple.isOSOpenBSD() || 152 TargetTriple.isMusl()) 153 SecurePlt = true; 154 155 if (HasSPE && IsPPC64) 156 report_fatal_error( "SPE is only supported for 32-bit targets.\n", false); 157 if (HasSPE && (HasAltivec || HasVSX || HasFPU)) 158 report_fatal_error( 159 "SPE and traditional floating point cannot both be enabled.\n", false); 160 161 // If not SPE, set standard FPU 162 if (!HasSPE) 163 HasFPU = true; 164 165 StackAlignment = getPlatformStackAlignment(); 166 167 // Determine endianness. 168 // FIXME: Part of the TargetMachine. 169 IsLittleEndian = (TargetTriple.getArch() == Triple::ppc64le); 170 } 171 172 bool PPCSubtarget::enableMachineScheduler() const { return true; } 173 174 bool PPCSubtarget::enableMachinePipeliner() const { 175 return getSchedModel().hasInstrSchedModel() && EnableMachinePipeliner; 176 } 177 178 bool PPCSubtarget::useDFAforSMS() const { return false; } 179 180 // This overrides the PostRAScheduler bit in the SchedModel for each CPU. 181 bool PPCSubtarget::enablePostRAScheduler() const { return true; } 182 183 PPCGenSubtargetInfo::AntiDepBreakMode PPCSubtarget::getAntiDepBreakMode() const { 184 return TargetSubtargetInfo::ANTIDEP_ALL; 185 } 186 187 void PPCSubtarget::getCriticalPathRCs(RegClassVector &CriticalPathRCs) const { 188 CriticalPathRCs.clear(); 189 CriticalPathRCs.push_back(isPPC64() ? 190 &PPC::G8RCRegClass : &PPC::GPRCRegClass); 191 } 192 193 void PPCSubtarget::overrideSchedPolicy(MachineSchedPolicy &Policy, 194 unsigned NumRegionInstrs) const { 195 // The GenericScheduler that we use defaults to scheduling bottom up only. 196 // We want to schedule from both the top and the bottom and so we set 197 // OnlyBottomUp to false. 198 // We want to do bi-directional scheduling since it provides a more balanced 199 // schedule leading to better performance. 200 Policy.OnlyBottomUp = false; 201 // Spilling is generally expensive on all PPC cores, so always enable 202 // register-pressure tracking. 203 Policy.ShouldTrackPressure = true; 204 } 205 206 bool PPCSubtarget::useAA() const { 207 return true; 208 } 209 210 bool PPCSubtarget::enableSubRegLiveness() const { 211 return UseSubRegLiveness; 212 } 213 214 bool PPCSubtarget::isGVIndirectSymbol(const GlobalValue *GV) const { 215 // Large code model always uses the TOC even for local symbols. 216 if (TM.getCodeModel() == CodeModel::Large) 217 return true; 218 if (TM.shouldAssumeDSOLocal(*GV->getParent(), GV)) 219 return false; 220 return true; 221 } 222 223 bool PPCSubtarget::isELFv2ABI() const { return TM.isELFv2ABI(); } 224 bool PPCSubtarget::isPPC64() const { return TM.isPPC64(); } 225 226 bool PPCSubtarget::isUsingPCRelativeCalls() const { 227 return isPPC64() && hasPCRelativeMemops() && isELFv2ABI() && 228 CodeModel::Medium == getTargetMachine().getCodeModel(); 229 } 230