[SystemZ] [z/OS] Add SystemZCallingConventionRegisters class

[Everybody0523]

Summary

This patch adds the abstract class SystemZCallingConventionRegisters which is a SystemZ-specific class detailing special registers used by calling conventions on the target. SystemZELFRegisters and SystemZXPLINK64Registers implement this class for ELF and XPLINK64 respectively.

[Everybody0523]

clang format

[uweigand]

LGTM, thanks!

llvm/lib/Target/SystemZ/SystemZInstrInfo.cpp

 static uint64_t allOnes(unsigned int Count) {
   return Count == 0 ? 0 : (uint64_t(1) << (Count - 1) << 1) - 1;
 }
 
 // Pin the vtable to this file.
 void SystemZInstrInfo::anchor() {}
 
 SystemZInstrInfo::SystemZInstrInfo(SystemZSubtarget &sti)
     : SystemZGenInstrInfo(SystemZ::ADJCALLSTACKDOWN, SystemZ::ADJCALLSTACKUP),
-    RI(), STI(sti) {
-}
+      RI(sti.getSpecialRegisters()->getReturnFunctionAddressRegister()),
+      STI(sti) {}
 
 // MI is a 128-bit load or store.  Split it into two 64-bit loads or stores,
 // each having the opcode given by NewOpcode.
 void SystemZInstrInfo::splitMove(MachineBasicBlock::iterator MI,
                                  unsigned NewOpcode) const {
   MachineBasicBlock *MBB = MI->getParent();
   MachineFunction &MF = *MBB->getParent();
 

llvm/lib/Target/SystemZ/SystemZRegisterInfo.h

 inline bool isHighReg(unsigned int Reg) {
   if (SystemZ::GRH32BitRegClass.contains(Reg))
     return true;
   assert(SystemZ::GR32BitRegClass.contains(Reg) && "Invalid GRX32");
   return false;
 }
 } // end namespace SystemZ
 
+/// A SystemZ-specific class detailing special use registers
+/// particular for calling conventions.
+/// It is abstract, all calling conventions must override and
+/// define the pure virtual member function defined in this class.
+class SystemZCallingConventionRegisters {
+public:
+  /// \returns the register that keeps the
+  /// return function address.
+  virtual int getReturnFunctionAddressRegister() = 0;
+
+  /// \returns the register that keeps the
+  /// stack pointer address.
+  virtual int getStackPointerRegister() = 0;
+
+  /// \returns the register that keeps the
+  /// frame pointer address.
+  virtual int getFramePointerRegister() = 0;
+
+  /// \returns an array of all the callee saved registers.
+  virtual const MCPhysReg *
+  getCalleeSavedRegs(const MachineFunction *MF) const = 0;
+
+  /// \returns the mask of all the call preserved registers.
+  virtual const uint32_t *getCallPreservedMask(const MachineFunction &MF,
+                                               CallingConv::ID CC) const = 0;
+
+  /// Destroys the object. Bogus destructor allowing derived classes
+  /// to override it.
+  virtual ~SystemZCallingConventionRegisters(){};
+};
+
+/// XPLINK64 calling convention specific use registers
+/// Particular to z/OS when in 64 bit mode
+class SystemZXPLINK64Registers : public SystemZCallingConventionRegisters {
+public:
+  int getReturnFunctionAddressRegister() override final {
+    return SystemZ::R7D;
+  };
+
+  int getStackPointerRegister() override final { return SystemZ::R4D; };
+
+  int getFramePointerRegister() override final { return SystemZ::R8D; };
+
+  const MCPhysReg *
+  getCalleeSavedRegs(const MachineFunction *MF) const override final;
+
+  const uint32_t *getCallPreservedMask(const MachineFunction &MF,
+                                       CallingConv::ID CC) const override final;
+
+  /// Destroys the object. Bogus destructor overriding base class destructor
+  ~SystemZXPLINK64Registers(){};
+};
+
+/// ELF calling convention specific use registers
+/// Particular when on zLinux in 64 bit mode
+class SystemZELFRegisters : public SystemZCallingConventionRegisters {
+public:
+  int getReturnFunctionAddressRegister() override final {
+    return SystemZ::R14D;
+  };
+
+  int getStackPointerRegister() override final { return SystemZ::R15D; };
+
+  int getFramePointerRegister() override final { return SystemZ::R11D; };
+
+  const MCPhysReg *
+  getCalleeSavedRegs(const MachineFunction *MF) const override final;
+
+  const uint32_t *getCallPreservedMask(const MachineFunction &MF,
+                                       CallingConv::ID CC) const override final;
+
+  /// Destroys the object. Bogus destructor overriding base class destructor
+  ~SystemZELFRegisters(){};
+};
+
 struct SystemZRegisterInfo : public SystemZGenRegisterInfo {
 public:
-  SystemZRegisterInfo();
+  SystemZRegisterInfo(unsigned int RA);
 
   /// getPointerRegClass - Return the register class to use to hold pointers.
   /// This is currently only used by LOAD_STACK_GUARD, which requires a non-%r0
   /// register, hence ADDR64.
   const TargetRegisterClass *
   getPointerRegClass(const MachineFunction &MF,
                      unsigned Kind=0) const override {
     return &SystemZ::ADDR64BitRegClass;

llvm/lib/Target/SystemZ/SystemZRegisterInfo.cpp

 #include "llvm/CodeGen/VirtRegMap.h"
 #include "llvm/IR/DebugInfoMetadata.h"
 
 using namespace llvm;
 
 #define GET_REGINFO_TARGET_DESC
 #include "SystemZGenRegisterInfo.inc"
 
-SystemZRegisterInfo::SystemZRegisterInfo()
-    : SystemZGenRegisterInfo(SystemZ::R14D) {}
-
 // Given that MO is a GRX32 operand, return either GR32 or GRH32 if MO
 // somehow belongs in it. Otherwise, return GRX32.
 static const TargetRegisterClass *getRC32(MachineOperand &MO,
                                           const VirtRegMap *VRM,
                                           const MachineRegisterInfo *MRI) {
   const TargetRegisterClass *RC = MRI->getRegClass(MO.getReg());
 
   if (SystemZ::GR32BitRegClass.hasSubClassEq(RC) ||
while (Worklist.size()) {
       }
     }
   }
 
   return BaseImplRetVal;
 }
 
 const MCPhysReg *
-SystemZRegisterInfo::getCalleeSavedRegs(const MachineFunction *MF) const {
+SystemZXPLINK64Registers::getCalleeSavedRegs(const MachineFunction *MF) const {
+  return CSR_SystemZ_XPLINK64_SaveList;
+}
+
+const MCPhysReg *
+SystemZELFRegisters::getCalleeSavedRegs(const MachineFunction *MF) const {
   const SystemZSubtarget &Subtarget = MF->getSubtarget<SystemZSubtarget>();
   if (MF->getFunction().getCallingConv() == CallingConv::GHC)
     return CSR_SystemZ_NoRegs_SaveList;
   if (MF->getFunction().getCallingConv() == CallingConv::AnyReg)
     return Subtarget.hasVector()? CSR_SystemZ_AllRegs_Vector_SaveList
                                 : CSR_SystemZ_AllRegs_SaveList;
   if (MF->getSubtarget().getTargetLowering()->supportSwiftError() &&
       MF->getFunction().getAttributes().hasAttrSomewhere(
           Attribute::SwiftError))
     return CSR_SystemZ_SwiftError_SaveList;
   return CSR_SystemZ_ELF_SaveList;
 }
 
 const uint32_t *
-SystemZRegisterInfo::getCallPreservedMask(const MachineFunction &MF,
+SystemZXPLINK64Registers::getCallPreservedMask(const MachineFunction &MF,
+                                               CallingConv::ID CC) const {
+  return CSR_SystemZ_XPLINK64_RegMask;
+}
+
+const uint32_t *
+SystemZELFRegisters::getCallPreservedMask(const MachineFunction &MF,
                                           CallingConv::ID CC) const {
   const SystemZSubtarget &Subtarget = MF.getSubtarget<SystemZSubtarget>();
   if (CC == CallingConv::GHC)
     return CSR_SystemZ_NoRegs_RegMask;
   if (CC == CallingConv::AnyReg)
     return Subtarget.hasVector()? CSR_SystemZ_AllRegs_Vector_RegMask
                                 : CSR_SystemZ_AllRegs_RegMask;
   if (MF.getSubtarget().getTargetLowering()->supportSwiftError() &&
       MF.getFunction().getAttributes().hasAttrSomewhere(
           Attribute::SwiftError))
     return CSR_SystemZ_SwiftError_RegMask;
   return CSR_SystemZ_ELF_RegMask;
 }
 
+SystemZRegisterInfo::SystemZRegisterInfo(unsigned int RA)
+    : SystemZGenRegisterInfo(RA) {}
+
+const MCPhysReg *
+SystemZRegisterInfo::getCalleeSavedRegs(const MachineFunction *MF) const {
+
+  const SystemZSubtarget *Subtarget = &MF->getSubtarget<SystemZSubtarget>();
+  SystemZCallingConventionRegisters *Regs = Subtarget->getSpecialRegisters();
+
+  return Regs->getCalleeSavedRegs(MF);
+}
+
+const uint32_t *
+SystemZRegisterInfo::getCallPreservedMask(const MachineFunction &MF,
+                                          CallingConv::ID CC) const {
+
+  const SystemZSubtarget *Subtarget = &MF.getSubtarget<SystemZSubtarget>();
+  SystemZCallingConventionRegisters *Regs = Subtarget->getSpecialRegisters();
+  return Regs->getCallPreservedMask(MF, CC);
+}
+
 BitVector
 SystemZRegisterInfo::getReservedRegs(const MachineFunction &MF) const {
   BitVector Reserved(getNumRegs());
   const SystemZFrameLowering *TFI = getFrameLowering(MF);
-
-  if (TFI->hasFP(MF)) {
-    // R11D is the frame pointer.  Reserve all aliases.
-    Reserved.set(SystemZ::R11D);
-    Reserved.set(SystemZ::R11L);
-    Reserved.set(SystemZ::R11H);
-    Reserved.set(SystemZ::R10Q);
-  }
-
-  // R15D is the stack pointer.  Reserve all aliases.
-  Reserved.set(SystemZ::R15D);
-  Reserved.set(SystemZ::R15L);
-  Reserved.set(SystemZ::R15H);
-  Reserved.set(SystemZ::R14Q);
+  const SystemZSubtarget *Subtarget = &MF.getSubtarget<SystemZSubtarget>();
+  SystemZCallingConventionRegisters *Regs = Subtarget->getSpecialRegisters();
+  if (TFI->hasFP(MF))
+    // The frame pointer. Reserve all aliases.
+    for (MCRegAliasIterator AI(Regs->getFramePointerRegister(), this, true);
+         AI.isValid(); ++AI)
+      Reserved.set(*AI);
+
+  // Reserve all aliases for the stack pointer.
+  for (MCRegAliasIterator AI(Regs->getStackPointerRegister(), this, true);
+       AI.isValid(); ++AI)
+    Reserved.set(*AI);
 
   // A0 and A1 hold the thread pointer.
   Reserved.set(SystemZ::A0);
   Reserved.set(SystemZ::A1);
 
   // FPC is the floating-point control register.
   Reserved.set(SystemZ::FPC);
 
if (PhysClobbered.count() > (NewRC->getNumRegs() - DemandedFreeGR128))
     return false;
 
   return true;
 }
 
 Register
 SystemZRegisterInfo::getFrameRegister(const MachineFunction &MF) const {
   const SystemZFrameLowering *TFI = getFrameLowering(MF);
-  return TFI->hasFP(MF) ? SystemZ::R11D : SystemZ::R15D;
+  const SystemZSubtarget *Subtarget = &MF.getSubtarget<SystemZSubtarget>();
+  SystemZCallingConventionRegisters *Regs = Subtarget->getSpecialRegisters();
+
+  return TFI->hasFP(MF) ? Regs->getFramePointerRegister()
+                        : Regs->getStackPointerRegister();
 }
 
 const TargetRegisterClass *
 SystemZRegisterInfo::getCrossCopyRegClass(const TargetRegisterClass *RC) const {
   if (RC == &SystemZ::CCRRegClass)
     return &SystemZ::GR32BitRegClass;
   return RC;
 }
 

llvm/lib/Target/SystemZ/SystemZSubtarget.h

protected:
   bool HasVectorEnhancements2;
   bool HasVectorPackedDecimalEnhancement;
   bool HasEnhancedSort;
   bool HasDeflateConversion;
   bool HasSoftFloat;
 
 private:
   Triple TargetTriple;
+  SystemZCallingConventionRegisters *SpecialRegisters;
   SystemZInstrInfo InstrInfo;
   SystemZTargetLowering TLInfo;
   SystemZSelectionDAGInfo TSInfo;
   SystemZFrameLowering FrameLowering;
 
   SystemZSubtarget &initializeSubtargetDependencies(StringRef CPU,
                                                     StringRef FS);
+  SystemZCallingConventionRegisters *initializeSpecialRegisters(void);
+
 public:
   SystemZSubtarget(const Triple &TT, const std::string &CPU,
                    const std::string &FS, const TargetMachine &TM);
 
+  ~SystemZSubtarget();
+
+  SystemZCallingConventionRegisters *getSpecialRegisters() const {
+    assert(SpecialRegisters && "Unsupported SystemZ calling convention");
+    return SpecialRegisters;
+  }
+
   const TargetFrameLowering *getFrameLowering() const override {
     return &FrameLowering;
   }
   const SystemZInstrInfo *getInstrInfo() const override { return &InstrInfo; }
   const SystemZRegisterInfo *getRegisterInfo() const override {
     return &InstrInfo.getRegisterInfo();
   }
   const SystemZTargetLowering *getTargetLowering() const override {

llvm/lib/Target/SystemZ/SystemZSubtarget.cpp

if (!HasVector) {
     HasVectorEnhancements2 = false;
     HasVectorPackedDecimal = false;
     HasVectorPackedDecimalEnhancement = false;
   }
 
   return *this;
 }
 
+SystemZCallingConventionRegisters *
+SystemZSubtarget::initializeSpecialRegisters() {
+  if (isTargetXPLINK64())
+    return new SystemZXPLINK64Registers;
+  else if (isTargetELF())
+    return new SystemZELFRegisters;
+  else {
+    llvm_unreachable("Invalid Calling Convention. Cannot initialize Special "
+                     "Call Registers!");
+  }
+}
+
 SystemZSubtarget::SystemZSubtarget(const Triple &TT, const std::string &CPU,
                                    const std::string &FS,
                                    const TargetMachine &TM)
     : SystemZGenSubtargetInfo(TT, CPU, /*TuneCPU*/ CPU, FS),
       HasDistinctOps(false), HasLoadStoreOnCond(false), HasHighWord(false),
       HasFPExtension(false), HasPopulationCount(false),
       HasMessageSecurityAssist3(false), HasMessageSecurityAssist4(false),
       HasResetReferenceBitsMultiple(false), HasFastSerialization(false),
       HasInterlockedAccess1(false), HasMiscellaneousExtensions(false),
       HasExecutionHint(false), HasLoadAndTrap(false),
       HasTransactionalExecution(false), HasProcessorAssist(false),
-      HasDFPZonedConversion(false), HasEnhancedDAT2(false),
-      HasVector(false), HasLoadStoreOnCond2(false),
-      HasLoadAndZeroRightmostByte(false), HasMessageSecurityAssist5(false),
-      HasDFPPackedConversion(false),
+      HasDFPZonedConversion(false), HasEnhancedDAT2(false), HasVector(false),
+      HasLoadStoreOnCond2(false), HasLoadAndZeroRightmostByte(false),
+      HasMessageSecurityAssist5(false), HasDFPPackedConversion(false),
       HasMiscellaneousExtensions2(false), HasGuardedStorage(false),
       HasMessageSecurityAssist7(false), HasMessageSecurityAssist8(false),
       HasVectorEnhancements1(false), HasVectorPackedDecimal(false),
-      HasInsertReferenceBitsMultiple(false),
-      HasMiscellaneousExtensions3(false), HasMessageSecurityAssist9(false),
-      HasVectorEnhancements2(false), HasVectorPackedDecimalEnhancement(false),
-      HasEnhancedSort(false), HasDeflateConversion(false), HasSoftFloat(false),
-      TargetTriple(TT), InstrInfo(initializeSubtargetDependencies(CPU, FS)),
-      TLInfo(TM, *this), TSInfo(), FrameLowering() {}
+      HasInsertReferenceBitsMultiple(false), HasMiscellaneousExtensions3(false),
+      HasMessageSecurityAssist9(false), HasVectorEnhancements2(false),
+      HasVectorPackedDecimalEnhancement(false), HasEnhancedSort(false),
+      HasDeflateConversion(false), HasSoftFloat(false), TargetTriple(TT),
+      SpecialRegisters(initializeSpecialRegisters()),
+      InstrInfo(initializeSubtargetDependencies(CPU, FS)), TLInfo(TM, *this),
+      TSInfo(), FrameLowering() {}
 
+SystemZSubtarget::~SystemZSubtarget() { delete getSpecialRegisters(); }
 
 bool SystemZSubtarget::enableSubRegLiveness() const {
   return UseSubRegLiveness;
 }
 
 bool SystemZSubtarget::isPC32DBLSymbol(const GlobalValue *GV,
                                        CodeModel::Model CM) const {
   // PC32DBL accesses require the low bit to be clear.