1 //===-- SystemZSubtarget.cpp - SystemZ 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 #include "SystemZSubtarget.h" 10 #include "llvm/CodeGen/TargetLoweringObjectFileImpl.h" 11 #include "llvm/IR/GlobalValue.h" 12 #include "llvm/Target/TargetMachine.h" 13 14 using namespace llvm; 15 16 #define DEBUG_TYPE "systemz-subtarget" 17 18 #define GET_SUBTARGETINFO_TARGET_DESC 19 #define GET_SUBTARGETINFO_CTOR 20 #include "SystemZGenSubtargetInfo.inc" 21 22 static cl::opt<bool> UseSubRegLiveness( 23 "systemz-subreg-liveness", 24 cl::desc("Enable subregister liveness tracking for SystemZ (experimental)"), 25 cl::Hidden); 26 27 // Pin the vtable to this file. 28 void SystemZSubtarget::anchor() {} 29 30 SystemZSubtarget &SystemZSubtarget::initializeSubtargetDependencies( 31 StringRef CPU, StringRef TuneCPU, StringRef FS) { 32 if (CPU.empty()) 33 CPU = "generic"; 34 if (TuneCPU.empty()) 35 TuneCPU = CPU; 36 // Parse features string. 37 ParseSubtargetFeatures(CPU, TuneCPU, FS); 38 39 // -msoft-float implies -mno-vx. 40 if (HasSoftFloat) 41 HasVector = false; 42 43 // -mno-vx implicitly disables all vector-related features. 44 if (!HasVector) { 45 HasVectorEnhancements1 = false; 46 HasVectorEnhancements2 = false; 47 HasVectorEnhancements3 = false; 48 HasVectorPackedDecimal = false; 49 HasVectorPackedDecimalEnhancement = false; 50 HasVectorPackedDecimalEnhancement2 = false; 51 HasVectorPackedDecimalEnhancement3 = false; 52 } 53 54 return *this; 55 } 56 57 SystemZCallingConventionRegisters * 58 SystemZSubtarget::initializeSpecialRegisters() { 59 if (isTargetXPLINK64()) 60 return new SystemZXPLINK64Registers; 61 else if (isTargetELF()) 62 return new SystemZELFRegisters; 63 llvm_unreachable("Invalid Calling Convention. Cannot initialize Special " 64 "Call Registers!"); 65 } 66 67 SystemZSubtarget::SystemZSubtarget(const Triple &TT, const std::string &CPU, 68 const std::string &TuneCPU, 69 const std::string &FS, 70 const TargetMachine &TM) 71 : SystemZGenSubtargetInfo(TT, CPU, TuneCPU, FS), TargetTriple(TT), 72 SpecialRegisters(initializeSpecialRegisters()), 73 InstrInfo(initializeSubtargetDependencies(CPU, TuneCPU, FS)), 74 TLInfo(TM, *this), FrameLowering(SystemZFrameLowering::create(*this)) {} 75 76 bool SystemZSubtarget::enableSubRegLiveness() const { 77 return UseSubRegLiveness; 78 } 79 80 bool SystemZSubtarget::isAddressedViaADA(const GlobalValue *GV) const { 81 if (const auto *GO = dyn_cast<GlobalObject>(GV)) { 82 // A R/O variable is placed in code section. If the R/O variable has as 83 // least two byte alignment, then generated code can use relative 84 // instructions to address the variable. Otherwise, use the ADA to address 85 // the variable. 86 if (GO->getAlignment() & 0x1) { 87 return true; 88 } 89 90 // getKindForGlobal only works with definitions 91 if (GO->isDeclaration()) { 92 return true; 93 } 94 95 // check AvailableExternallyLinkage here as getKindForGlobal() asserts 96 if (GO->hasAvailableExternallyLinkage()) { 97 return true; 98 } 99 100 SectionKind GOKind = TargetLoweringObjectFile::getKindForGlobal( 101 GO, TLInfo.getTargetMachine()); 102 if (!GOKind.isReadOnly()) { 103 return true; 104 } 105 106 return false; // R/O variable with multiple of 2 byte alignment 107 } 108 return true; 109 } 110 111 bool SystemZSubtarget::isPC32DBLSymbol(const GlobalValue *GV, 112 CodeModel::Model CM) const { 113 if (isTargetzOS()) 114 return !isAddressedViaADA(GV); 115 116 // PC32DBL accesses require the low bit to be clear. 117 // 118 // FIXME: Explicitly check for functions: the datalayout is currently 119 // missing information about function pointers. 120 const DataLayout &DL = GV->getDataLayout(); 121 if (GV->getPointerAlignment(DL) == 1 && !GV->getValueType()->isFunctionTy()) 122 return false; 123 124 // For the small model, all locally-binding symbols are in range. 125 if (CM == CodeModel::Small) 126 return TLInfo.getTargetMachine().shouldAssumeDSOLocal(GV); 127 128 // For Medium and above, assume that the symbol is not within the 4GB range. 129 // Taking the address of locally-defined text would be OK, but that 130 // case isn't easy to detect. 131 return false; 132 } 133