133 lines · cpp
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-exception6//7//===----------------------------------------------------------------------===//8 9#include "SystemZSubtarget.h"10#include "llvm/CodeGen/TargetLoweringObjectFileImpl.h"11#include "llvm/IR/GlobalVariable.h"12#include "llvm/Target/TargetMachine.h"13 14using namespace llvm;15 16#define DEBUG_TYPE "systemz-subtarget"17 18#define GET_SUBTARGETINFO_TARGET_DESC19#define GET_SUBTARGETINFO_CTOR20#include "SystemZGenSubtargetInfo.inc"21 22static 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.28void SystemZSubtarget::anchor() {}29 30SystemZSubtarget &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 57SystemZCallingConventionRegisters *58SystemZSubtarget::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 67SystemZSubtarget::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 76bool SystemZSubtarget::enableSubRegLiveness() const {77 return UseSubRegLiveness;78}79 80bool 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 as83 // least two byte alignment, then generated code can use relative84 // instructions to address the variable. Otherwise, use the ADA to address85 // the variable.86 if (auto *GV = dyn_cast<GlobalVariable>(GO))87 if (GV->getAlign() && (*GV->getAlign()).value() & 0x1)88 return true;89 90 // getKindForGlobal only works with definitions91 if (GO->isDeclaration()) {92 return true;93 }94 95 // check AvailableExternallyLinkage here as getKindForGlobal() asserts96 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 alignment107 }108 return true;109}110 111bool 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 currently119 // 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 that130 // case isn't easy to detect.131 return false;132}133