Revert "[SystemZ] Add support for __builtin_setjmp and __builtin_longjmp (#116642)"

This reverts commit 030bbc9.

Author: uweigand

clang/lib/Basic/Targets/SystemZ.h

@@ -247,8 +247,6 @@ class LLVM_LIBRARY_VISIBILITY SystemZTargetInfo : public TargetInfo {
     return RegNo < 4 ? 6 + RegNo : -1;
   }
 
-  bool hasSjLjLowering() const override { return true; }
-
   std::pair<unsigned, unsigned> hardwareInterferenceSizes() const override {
     return std::make_pair(256, 256);
   }

clang/lib/CodeGen/CGBuiltin.cpp

@@ -4860,14 +4860,6 @@ RValue CodeGenFunction::EmitBuiltinExpr(const GlobalDecl GD, unsigned BuiltinID,
     // Buffer is a void**.
     Address Buf = EmitPointerWithAlignment(E->getArg(0));
 
-    if (getTarget().getTriple().getArch() == llvm::Triple::systemz) {
-      // On this target, the back end fills in the context buffer completely.
-      // It doesn't really matter if the frontend stores to the buffer before
-      // calling setjmp, the back-end is going to overwrite them anyway.
-      Function *F = CGM.getIntrinsic(Intrinsic::eh_sjlj_setjmp);
-      return RValue::get(Builder.CreateCall(F, Buf.emitRawPointer(*this)));
-    }
-
     // Store the frame pointer to the setjmp buffer.
     Value *FrameAddr = Builder.CreateCall(
         CGM.getIntrinsic(Intrinsic::frameaddress, AllocaInt8PtrTy),

clang/test/CodeGen/SystemZ/builtin-setjmp-logjmp.c

@@ -374,11 +374,10 @@ overall functioning of this intrinsic is compatible with the GCC
 to interoperate.
 
 The single parameter is a pointer to a five word buffer in which the calling
-context is saved. The format and contents of the buffer are target-specific.
-On certain targets (ARM, PowerPC, VE, X86), the front end places the 
-frame pointer in the first word and the stack pointer in the third word, 
-while the target implementation of this intrinsic fills in the remaining 
-words.  On other targets (SystemZ), saving the calling context to the buffer is left completely to the target implementation. 
+context is saved. The front end places the frame pointer in the first word, and
+the target implementation of this intrinsic should place the destination address
+for a `llvm.eh.sjlj.longjmp`_ in the second word. The following three words are
+available for use in a target-specific manner.
 
 .. _llvm.eh.sjlj.longjmp:
 

llvm/docs/ExceptionHandling.rst

@@ -705,11 +705,6 @@ void SystemZAsmPrinter::emitInstruction(const MachineInstr *MI) {
     return;
   }
 
-  // EH_SjLj_Setup is a dummy terminator instruction of size 0.
-  // It is used to handle the clobber register for builtin setjmp.
-  case SystemZ::EH_SjLj_Setup:
-    return;
-
   default:
     Lower.lower(MI, LoweredMI);
     break;

llvm/lib/Target/SystemZ/SystemZAsmPrinter.cpp

@@ -751,11 +751,6 @@ SystemZTargetLowering::SystemZTargetLowering(const TargetMachine &TM,
   setOperationAction(ISD::INTRINSIC_W_CHAIN, MVT::Other, Custom);
   setOperationAction(ISD::INTRINSIC_WO_CHAIN, MVT::Other, Custom);
 
-  // We're not using SJLJ for exception handling, but they're implemented
-  // solely to support use of __builtin_setjmp / __builtin_longjmp.
-  setOperationAction(ISD::EH_SJLJ_SETJMP, MVT::i32, Custom);
-  setOperationAction(ISD::EH_SJLJ_LONGJMP, MVT::Other, Custom);
-
   // We want to use MVC in preference to even a single load/store pair.
   MaxStoresPerMemcpy = Subtarget.hasVector() ? 2 : 0;
   MaxStoresPerMemcpyOptSize = 0;
@@ -945,240 +940,6 @@ bool SystemZTargetLowering::isFPImmLegal(const APFloat &Imm, EVT VT,
   return SystemZVectorConstantInfo(Imm).isVectorConstantLegal(Subtarget);
 }
 
-MachineBasicBlock *
-SystemZTargetLowering::emitEHSjLjSetJmp(MachineInstr &MI,
-                                        MachineBasicBlock *MBB) const {
-  DebugLoc DL = MI.getDebugLoc();
-  const TargetInstrInfo *TII = Subtarget.getInstrInfo();
-  const SystemZRegisterInfo *TRI = Subtarget.getRegisterInfo();
-
-  MachineFunction *MF = MBB->getParent();
-  MachineRegisterInfo &MRI = MF->getRegInfo();
-
-  const BasicBlock *BB = MBB->getBasicBlock();
-  MachineFunction::iterator I = ++MBB->getIterator();
-
-  Register DstReg = MI.getOperand(0).getReg();
-  const TargetRegisterClass *RC = MRI.getRegClass(DstReg);
-  assert(TRI->isTypeLegalForClass(*RC, MVT::i32) && "Invalid destination!");
-  Register mainDstReg = MRI.createVirtualRegister(RC);
-  Register restoreDstReg = MRI.createVirtualRegister(RC);
-
-  MVT PVT = getPointerTy(MF->getDataLayout());
-  assert((PVT == MVT::i64 || PVT == MVT::i32) && "Invalid Pointer Size!");
-  // For v = setjmp(buf), we generate.
-  // Algorithm:
-  //
-  //                 ---------
-  //                | thisMBB |
-  //                 ---------
-  //                     |
-  //         ------------------------
-  //        |                        |
-  //     ----------           ---------------
-  //    |  mainMBB |         | restoreMBB    |
-  //    |   v = 0  |         |  v = 1        |
-  //     ----------           ---------------
-  //        |                        |
-  //         -------------------------
-  //                     |
-  //           -----------------------------
-  //          |       sinkMBB               |
-  //          | phi(v_mainMBB,v_restoreMBB) |
-  //           -----------------------------
-  // thisMBB:
-  //  buf[FPOffset] = Frame Pointer if hasFP.
-  //  buf[LabelOffset] = restoreMBB <-- takes address of restoreMBB.
-  //  buf[BCOffset] = Backchain value if building with -mbackchain.
-  //  buf[SPOffset] = Stack Pointer.
-  //  buf[LPOffset] = We never write this slot with  R13, gcc stores R13 always.
-  //  SjLjSetup restoreMBB
-  // mainMBB:
-  //  v_main = 0
-  // sinkMBB:
-  //  v = phi(v_main, v_restore)
-  // restoreMBB:
-  //  v_restore = 1
-
-  MachineBasicBlock *thisMBB = MBB;
-  MachineBasicBlock *mainMBB = MF->CreateMachineBasicBlock(BB);
-  MachineBasicBlock *sinkMBB = MF->CreateMachineBasicBlock(BB);
-  MachineBasicBlock *restoreMBB = MF->CreateMachineBasicBlock(BB);
-
-  MF->insert(I, mainMBB);
-  MF->insert(I, sinkMBB);
-  MF->push_back(restoreMBB);
-  restoreMBB->setMachineBlockAddressTaken();
-
-  MachineInstrBuilder MIB;
-
-  // Transfer the remainder of BB and its successor edges to sinkMBB.
-  sinkMBB->splice(sinkMBB->begin(), MBB,
-                  std::next(MachineBasicBlock::iterator(MI)), MBB->end());
-  sinkMBB->transferSuccessorsAndUpdatePHIs(MBB);
-
-  // thisMBB:
-  const int64_t FPOffset = 0;                         // Slot 1.
-  const int64_t LabelOffset = 1 * PVT.getStoreSize(); // Slot 2.
-  const int64_t BCOffset = 2 * PVT.getStoreSize();    // Slot 3.
-  const int64_t SPOffset = 3 * PVT.getStoreSize();    // Slot 4.
-
-  // Buf address.
-  Register BufReg = MI.getOperand(1).getReg();
-
-  const TargetRegisterClass *PtrRC = getRegClassFor(PVT);
-  unsigned LabelReg = MRI.createVirtualRegister(PtrRC);
-
-  // Prepare IP for longjmp.
-  BuildMI(*thisMBB, MI, DL, TII->get(SystemZ::LARL), LabelReg)
-      .addMBB(restoreMBB);
-  // Store IP for return from jmp, slot 2, offset = 1.
-  BuildMI(*thisMBB, MI, DL, TII->get(SystemZ::STG))
-      .addReg(LabelReg)
-      .addReg(BufReg)
-      .addImm(LabelOffset)
-      .addReg(0);
-
-  auto *SpecialRegs = Subtarget.getSpecialRegisters();
-  bool HasFP = Subtarget.getFrameLowering()->hasFP(*MF);
-  if (HasFP) {
-    BuildMI(*thisMBB, MI, DL, TII->get(SystemZ::STG))
-        .addReg(SpecialRegs->getFramePointerRegister())
-        .addReg(BufReg)
-        .addImm(FPOffset)
-        .addReg(0);
-  }
-
-  // Store SP.
-  BuildMI(*thisMBB, MI, DL, TII->get(SystemZ::STG))
-      .addReg(SpecialRegs->getStackPointerRegister())
-      .addReg(BufReg)
-      .addImm(SPOffset)
-      .addReg(0);
-
-  // Slot 3(Offset = 2) Backchain value (if building with -mbackchain).
-  bool BackChain = MF->getSubtarget<SystemZSubtarget>().hasBackChain();
-  if (BackChain) {
-    Register BCReg = MRI.createVirtualRegister(RC);
-    auto *TFL = Subtarget.getFrameLowering<SystemZFrameLowering>();
-    MIB = BuildMI(*thisMBB, MI, DL, TII->get(SystemZ::LG), BCReg)
-              .addReg(SpecialRegs->getStackPointerRegister())
-              .addImm(TFL->getBackchainOffset(*MF))
-              .addReg(0);
-
-    BuildMI(*thisMBB, MI, DL, TII->get(SystemZ::STG))
-        .addReg(BCReg)
-        .addReg(BufReg)
-        .addImm(BCOffset)
-        .addReg(0);
-  }
-
-  // Setup.
-  MIB = BuildMI(*thisMBB, MI, DL, TII->get(SystemZ::EH_SjLj_Setup))
-            .addMBB(restoreMBB);
-
-  const SystemZRegisterInfo *RegInfo = Subtarget.getRegisterInfo();
-  MIB.addRegMask(RegInfo->getNoPreservedMask());
-
-  thisMBB->addSuccessor(mainMBB);
-  thisMBB->addSuccessor(restoreMBB);
-
-  // mainMBB:
-  BuildMI(mainMBB, DL, TII->get(SystemZ::LHI), mainDstReg).addImm(0);
-  mainMBB->addSuccessor(sinkMBB);
-
-  // sinkMBB:
-  BuildMI(*sinkMBB, sinkMBB->begin(), DL, TII->get(SystemZ::PHI), DstReg)
-      .addReg(mainDstReg)
-      .addMBB(mainMBB)
-      .addReg(restoreDstReg)
-      .addMBB(restoreMBB);
-
-  // restoreMBB.
-  BuildMI(restoreMBB, DL, TII->get(SystemZ::LHI), restoreDstReg).addImm(1);
-  BuildMI(restoreMBB, DL, TII->get(SystemZ::J)).addMBB(sinkMBB);
-  restoreMBB->addSuccessor(sinkMBB);
-
-  MI.eraseFromParent();
-
-  return sinkMBB;
-}
-
-MachineBasicBlock *
-SystemZTargetLowering::emitEHSjLjLongJmp(MachineInstr &MI,
-                                         MachineBasicBlock *MBB) const {
-
-  DebugLoc DL = MI.getDebugLoc();
-  const TargetInstrInfo *TII = Subtarget.getInstrInfo();
-
-  MachineFunction *MF = MBB->getParent();
-  MachineRegisterInfo &MRI = MF->getRegInfo();
-
-  MVT PVT = getPointerTy(MF->getDataLayout());
-  assert((PVT == MVT::i64 || PVT == MVT::i32) && "Invalid Pointer Size!");
-  Register BufReg = MI.getOperand(0).getReg();
-  const TargetRegisterClass *RC = MRI.getRegClass(BufReg);
-  auto *SpecialRegs = Subtarget.getSpecialRegisters();
-
-  Register Tmp = MRI.createVirtualRegister(RC);
-  Register BCReg = MRI.createVirtualRegister(RC);
-
-  MachineInstrBuilder MIB;
-
-  const int64_t FPOffset = 0;
-  const int64_t LabelOffset = 1 * PVT.getStoreSize();
-  const int64_t BCOffset = 2 * PVT.getStoreSize();
-  const int64_t SPOffset = 3 * PVT.getStoreSize();
-  const int64_t LPOffset = 4 * PVT.getStoreSize();
-
-  MIB = BuildMI(*MBB, MI, DL, TII->get(SystemZ::LG), Tmp)
-            .addReg(BufReg)
-            .addImm(LabelOffset)
-            .addReg(0);
-
-  MIB = BuildMI(*MBB, MI, DL, TII->get(SystemZ::LG),
-                SpecialRegs->getFramePointerRegister())
-            .addReg(BufReg)
-            .addImm(FPOffset)
-            .addReg(0);
-
-  // We are restoring R13 even though we never stored in setjmp from llvm,
-  // as gcc always stores R13 in builtin_setjmp. We could have mixed code
-  // gcc setjmp and llvm longjmp.
-  MIB = BuildMI(*MBB, MI, DL, TII->get(SystemZ::LG), SystemZ::R13D)
-            .addReg(BufReg)
-            .addImm(LPOffset)
-            .addReg(0);
-
-  bool BackChain = MF->getSubtarget<SystemZSubtarget>().hasBackChain();
-  if (BackChain) {
-    MIB = BuildMI(*MBB, MI, DL, TII->get(SystemZ::LG), BCReg)
-              .addReg(BufReg)
-              .addImm(BCOffset)
-              .addReg(0);
-  }
-
-  MIB = BuildMI(*MBB, MI, DL, TII->get(SystemZ::LG),
-                SpecialRegs->getStackPointerRegister())
-            .addReg(BufReg)
-            .addImm(SPOffset)
-            .addReg(0);
-
-  if (BackChain) {
-    auto *TFL = Subtarget.getFrameLowering<SystemZFrameLowering>();
-    BuildMI(*MBB, MI, DL, TII->get(SystemZ::STG))
-        .addReg(BCReg)
-        .addReg(SpecialRegs->getStackPointerRegister())
-        .addImm(TFL->getBackchainOffset(*MF))
-        .addReg(0);
-  }
-
-  MIB = BuildMI(*MBB, MI, DL, TII->get(SystemZ::BR)).addReg(Tmp);
-
-  MI.eraseFromParent();
-  return MBB;
-}
-
 /// Returns true if stack probing through inline assembly is requested.
 bool SystemZTargetLowering::hasInlineStackProbe(const MachineFunction &MF) const {
   // If the function specifically requests inline stack probes, emit them.
@@ -6531,14 +6292,6 @@ SDValue SystemZTargetLowering::LowerOperation(SDValue Op,
     return lowerGET_ROUNDING(Op, DAG);
   case ISD::READCYCLECOUNTER:
     return lowerREADCYCLECOUNTER(Op, DAG);
-  case ISD::EH_SJLJ_SETJMP:
-  case ISD::EH_SJLJ_LONGJMP:
-    // These operations are legal on our platform, but we cannot actually
-    // set the operation action to Legal as common code would treat this
-    // as equivalent to Expand. Instead, we keep the operation action to
-    // Custom and just leave them unchanged here.
-    return Op;
-
   default:
     llvm_unreachable("Unexpected node to lower");
   }
@@ -9980,10 +9733,6 @@ MachineBasicBlock *SystemZTargetLowering::EmitInstrWithCustomInserter(
 
   case SystemZ::PROBED_ALLOCA:
     return emitProbedAlloca(MI, MBB);
-  case SystemZ::EH_SjLj_SetJmp:
-    return emitEHSjLjSetJmp(MI, MBB);
-  case SystemZ::EH_SjLj_LongJmp:
-    return emitEHSjLjLongJmp(MI, MBB);
 
   case TargetOpcode::STACKMAP:
   case TargetOpcode::PATCHPOINT:

llvm/lib/Target/SystemZ/SystemZISelLowering.cpp

@@ -476,12 +476,6 @@ class SystemZTargetLowering : public TargetLowering {
     // LD, and having the full constant in memory enables reg/mem opcodes.
     return VT != MVT::f64;
   }
-  MachineBasicBlock *emitEHSjLjSetJmp(MachineInstr &MI,
-                                      MachineBasicBlock *MBB) const;
-
-  MachineBasicBlock *emitEHSjLjLongJmp(MachineInstr &MI,
-                                       MachineBasicBlock *MBB) const;
-
   bool hasInlineStackProbe(const MachineFunction &MF) const override;
   AtomicExpansionKind shouldCastAtomicLoadInIR(LoadInst *LI) const override;
   AtomicExpansionKind shouldCastAtomicStoreInIR(StoreInst *SI) const override;

llvm/lib/Target/SystemZ/SystemZISelLowering.h

@@ -1862,23 +1862,6 @@ let mayLoad = 1, mayStore = 1, Defs = [CC] in {
   }
 }
 
-//--------------------------------------------------------------------------
-// Setjmp/Longjmp.
-//--------------------------------------------------------------------------
-let isBarrier = 1,  hasNoSchedulingInfo = 1 in {
-  let hasSideEffects = 1, usesCustomInserter = 1 in {
-    def EH_SjLj_SetJmp : Pseudo<(outs GR32:$dst), (ins ADDR64:$R2), 
-                        [(set GR32:$dst, (z_eh_sjlj_setjmp ADDR64:$R2))]>;
-    let isTerminator = 1 in {
-      def EH_SjLj_LongJmp : Pseudo<(outs), (ins ADDR64:$R2), 
-                           [(z_eh_sjlj_longjmp  ADDR64:$R2)]>;
-    }
-  }
-  let isTerminator = 1, isCodeGenOnly = 1, Size = 0 in {
-    def EH_SjLj_Setup : Pseudo<(outs), (ins brtarget32:$dst), []>;
-  }
-}
-
 //===----------------------------------------------------------------------===//
 // Message-security assist
 //===----------------------------------------------------------------------===//