Add __builtin_setjmp/_longjmp supprt in X86 backend

- Besides used in SjLj exception handling, __builtin_setjmp/__longjmp is also
  used as a light-weight replacement of setjmp/longjmp which are used to
  implementation continuation, user-level threading, and etc. The support added
  in this patch ONLY addresses this usage and is NOT intended to support SjLj
  exception handling as zero-cost DWARF exception handling is used by default
  in X86.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165989 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/X86/X86ISelDAGToDAG.cpp

@@ -1302,7 +1302,9 @@ bool X86DAGToDAGISel::SelectAddr(SDNode *Parent, SDValue N, SDValue &Base,
       // that are not a MemSDNode, and thus don't have proper addrspace info.
       Parent->getOpcode() != ISD::INTRINSIC_W_CHAIN && // unaligned loads, fixme
       Parent->getOpcode() != ISD::INTRINSIC_VOID && // nontemporal stores
-      Parent->getOpcode() != X86ISD::TLSCALL) { // Fixme
+      Parent->getOpcode() != X86ISD::TLSCALL && // Fixme
+      Parent->getOpcode() != X86ISD::EH_SJLJ_SETJMP && // setjmp
+      Parent->getOpcode() != X86ISD::EH_SJLJ_LONGJMP) { // longjmp
     unsigned AddrSpace =
       cast<MemSDNode>(Parent)->getPointerInfo().getAddrSpace();
     // AddrSpace 256 -> GS, 257 -> FS.

lib/Target/X86/X86ISelLowering.cpp

@@ -457,6 +457,14 @@ X86TargetLowering::X86TargetLowering(X86TargetMachine &TM)
     setOperationAction(ISD::SETCC         , MVT::i64  , Custom);
   }
   setOperationAction(ISD::EH_RETURN       , MVT::Other, Custom);
+  // NOTE: EH_SJLJ_SETJMP/_LONGJMP supported here is NOT intened to support
+  // SjLj exception handling but a light-weight setjmp/longjmp replacement to
+  // support continuation, user-level threading, and etc.. As a result, not
+  // other SjLj exception interfaces are implemented and please don't build
+  // your own exception handling based on them.
+  // LLVM/Clang supports zero-cost DWARF exception handling.
+  setOperationAction(ISD::EH_SJLJ_SETJMP, MVT::i32, Custom);
+  setOperationAction(ISD::EH_SJLJ_LONGJMP, MVT::Other, Custom);
 
   // Darwin ABI issue.
   setOperationAction(ISD::ConstantPool    , MVT::i32  , Custom);
@@ -10351,6 +10359,21 @@ SDValue X86TargetLowering::LowerEH_RETURN(SDValue Op, SelectionDAG &DAG) const {
                      Chain, DAG.getRegister(StoreAddrReg, getPointerTy()));
 }
 
+SDValue X86TargetLowering::lowerEH_SJLJ_SETJMP(SDValue Op,
+                                               SelectionDAG &DAG) const {
+  DebugLoc DL = Op.getDebugLoc();
+  return DAG.getNode(X86ISD::EH_SJLJ_SETJMP, DL,
+                     DAG.getVTList(MVT::i32, MVT::Other),
+                     Op.getOperand(0), Op.getOperand(1));
+}
+
+SDValue X86TargetLowering::lowerEH_SJLJ_LONGJMP(SDValue Op,
+                                                SelectionDAG &DAG) const {
+  DebugLoc DL = Op.getDebugLoc();
+  return DAG.getNode(X86ISD::EH_SJLJ_LONGJMP, DL, MVT::Other,
+                     Op.getOperand(0), Op.getOperand(1));
+}
+
 static SDValue LowerADJUST_TRAMPOLINE(SDValue Op, SelectionDAG &DAG) {
   return Op.getOperand(0);
 }
@@ -11375,6 +11398,8 @@ SDValue X86TargetLowering::LowerOperation(SDValue Op, SelectionDAG &DAG) const {
                                 return LowerFRAME_TO_ARGS_OFFSET(Op, DAG);
   case ISD::DYNAMIC_STACKALLOC: return LowerDYNAMIC_STACKALLOC(Op, DAG);
   case ISD::EH_RETURN:          return LowerEH_RETURN(Op, DAG);
+  case ISD::EH_SJLJ_SETJMP:     return lowerEH_SJLJ_SETJMP(Op, DAG);
+  case ISD::EH_SJLJ_LONGJMP:    return lowerEH_SJLJ_LONGJMP(Op, DAG);
   case ISD::INIT_TRAMPOLINE:    return LowerINIT_TRAMPOLINE(Op, DAG);
   case ISD::ADJUST_TRAMPOLINE:  return LowerADJUST_TRAMPOLINE(Op, DAG);
   case ISD::FLT_ROUNDS_:        return LowerFLT_ROUNDS_(Op, DAG);
@@ -11667,6 +11692,8 @@ const char *X86TargetLowering::getTargetNodeName(unsigned Opcode) const {
   case X86ISD::TLSADDR:            return "X86ISD::TLSADDR";
   case X86ISD::TLSBASEADDR:        return "X86ISD::TLSBASEADDR";
   case X86ISD::TLSCALL:            return "X86ISD::TLSCALL";
+  case X86ISD::EH_SJLJ_SETJMP:     return "X86ISD::EH_SJLJ_SETJMP";
+  case X86ISD::EH_SJLJ_LONGJMP:    return "X86ISD::EH_SJLJ_LONGJMP";
   case X86ISD::EH_RETURN:          return "X86ISD::EH_RETURN";
   case X86ISD::TC_RETURN:          return "X86ISD::TC_RETURN";
   case X86ISD::FNSTCW16m:          return "X86ISD::FNSTCW16m";
@@ -13212,6 +13239,173 @@ X86TargetLowering::EmitLoweredTLSCall(MachineInstr *MI,
   return BB;
 }
 
+MachineBasicBlock *
+X86TargetLowering::emitEHSjLjSetJmp(MachineInstr *MI,
+                                    MachineBasicBlock *MBB) const {
+  DebugLoc DL = MI->getDebugLoc();
+  const TargetInstrInfo *TII = getTargetMachine().getInstrInfo();
+
+  MachineFunction *MF = MBB->getParent();
+  MachineRegisterInfo &MRI = MF->getRegInfo();
+
+  const BasicBlock *BB = MBB->getBasicBlock();
+  MachineFunction::iterator I = MBB;
+  ++I;
+
+  // Memory Reference
+  MachineInstr::mmo_iterator MMOBegin = MI->memoperands_begin();
+  MachineInstr::mmo_iterator MMOEnd = MI->memoperands_end();
+
+  unsigned DstReg;
+  unsigned MemOpndSlot = 0;
+
+  unsigned CurOp = 0;
+
+  DstReg = MI->getOperand(CurOp++).getReg();
+  const TargetRegisterClass *RC = MRI.getRegClass(DstReg);
+  assert(RC->hasType(MVT::i32) && "Invalid destination!");
+  unsigned mainDstReg = MRI.createVirtualRegister(RC);
+  unsigned restoreDstReg = MRI.createVirtualRegister(RC);
+
+  MemOpndSlot = CurOp;
+
+  MVT PVT = getPointerTy();
+  assert((PVT == MVT::i64 || PVT == MVT::i32) &&
+         "Invalid Pointer Size!");
+
+  // For v = setjmp(buf), we generate
+  //
+  // thisMBB:
+  //  buf[Label_Offset] = ljMBB
+  //  SjLjSetup restoreMBB
+  //
+  // mainMBB:
+  //  v_main = 0
+  //
+  // sinkMBB:
+  //  v = phi(main, 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);
+
+  MachineInstrBuilder MIB;
+
+  // Transfer the remainder of BB and its successor edges to sinkMBB.
+  sinkMBB->splice(sinkMBB->begin(), MBB,
+                  llvm::next(MachineBasicBlock::iterator(MI)), MBB->end());
+  sinkMBB->transferSuccessorsAndUpdatePHIs(MBB);
+
+  // thisMBB:
+  unsigned PtrImmStoreOpc = (PVT == MVT::i64) ? X86::MOV64mi32 : X86::MOV32mi;
+  const int64_t Label_Offset = 1 * PVT.getStoreSize();
+
+  // Store IP
+  MIB = BuildMI(*thisMBB, MI, DL, TII->get(PtrImmStoreOpc));
+  for (unsigned i = 0; i < X86::AddrNumOperands; ++i) {
+    if (i == X86::AddrDisp)
+      MIB.addDisp(MI->getOperand(MemOpndSlot + i), Label_Offset);
+    else
+      MIB.addOperand(MI->getOperand(MemOpndSlot + i));
+  }
+  MIB.addMBB(restoreMBB);
+  MIB.setMemRefs(MMOBegin, MMOEnd);
+  // Setup
+  MIB = BuildMI(*thisMBB, MI, DL, TII->get(X86::EH_SjLj_Setup))
+          .addMBB(restoreMBB);
+  MIB.addRegMask(RegInfo->getNoPreservedMask());
+  thisMBB->addSuccessor(mainMBB);
+  thisMBB->addSuccessor(restoreMBB);
+
+  // mainMBB:
+  //  EAX = 0
+  BuildMI(mainMBB, DL, TII->get(X86::MOV32r0), mainDstReg);
+  mainMBB->addSuccessor(sinkMBB);
+
+  // sinkMBB:
+  BuildMI(*sinkMBB, sinkMBB->begin(), DL,
+          TII->get(X86::PHI), DstReg)
+    .addReg(mainDstReg).addMBB(mainMBB)
+    .addReg(restoreDstReg).addMBB(restoreMBB);
+
+  // restoreMBB:
+  BuildMI(restoreMBB, DL, TII->get(X86::MOV32ri), restoreDstReg).addImm(1);
+  BuildMI(restoreMBB, DL, TII->get(X86::JMP_4)).addMBB(sinkMBB);
+  restoreMBB->addSuccessor(sinkMBB);
+
+  MI->eraseFromParent();
+  return sinkMBB;
+}
+
+MachineBasicBlock *
+X86TargetLowering::emitEHSjLjLongJmp(MachineInstr *MI,
+                                     MachineBasicBlock *MBB) const {
+  DebugLoc DL = MI->getDebugLoc();
+  const TargetInstrInfo *TII = getTargetMachine().getInstrInfo();
+
+  MachineFunction *MF = MBB->getParent();
+  MachineRegisterInfo &MRI = MF->getRegInfo();
+
+  // Memory Reference
+  MachineInstr::mmo_iterator MMOBegin = MI->memoperands_begin();
+  MachineInstr::mmo_iterator MMOEnd = MI->memoperands_end();
+
+  MVT PVT = getPointerTy();
+  assert((PVT == MVT::i64 || PVT == MVT::i32) &&
+         "Invalid Pointer Size!");
+
+  const TargetRegisterClass *RC =
+    (PVT == MVT::i64) ? &X86::GR64RegClass : &X86::GR32RegClass;
+  unsigned Tmp = MRI.createVirtualRegister(RC);
+  // Since FP is only updated here but NOT referenced, it's treated as GPR.
+  unsigned FP = (PVT == MVT::i64) ? X86::RBP : X86::EBP;
+  unsigned SP = RegInfo->getStackRegister();
+
+  MachineInstrBuilder MIB;
+
+  const int64_t Label_Offset = 1 * PVT.getStoreSize();
+  const int64_t SP_Offset = 2 * PVT.getStoreSize();
+
+  unsigned PtrLoadOpc = (PVT == MVT::i64) ? X86::MOV64rm : X86::MOV32rm;
+  unsigned IJmpOpc = (PVT == MVT::i64) ? X86::JMP64r : X86::JMP32r;
+
+  // Reload FP
+  MIB = BuildMI(*MBB, MI, DL, TII->get(PtrLoadOpc), FP);
+  for (unsigned i = 0; i < X86::AddrNumOperands; ++i)
+    MIB.addOperand(MI->getOperand(i));
+  MIB.setMemRefs(MMOBegin, MMOEnd);
+  // Reload IP
+  MIB = BuildMI(*MBB, MI, DL, TII->get(PtrLoadOpc), Tmp);
+  for (unsigned i = 0; i < X86::AddrNumOperands; ++i) {
+    if (i == X86::AddrDisp)
+      MIB.addDisp(MI->getOperand(i), Label_Offset);
+    else
+      MIB.addOperand(MI->getOperand(i));
+  }
+  MIB.setMemRefs(MMOBegin, MMOEnd);
+  // Reload SP
+  MIB = BuildMI(*MBB, MI, DL, TII->get(PtrLoadOpc), SP);
+  for (unsigned i = 0; i < X86::AddrNumOperands; ++i) {
+    if (i == X86::AddrDisp)
+      MIB.addDisp(MI->getOperand(i), SP_Offset);
+    else
+      MIB.addOperand(MI->getOperand(i));
+  }
+  MIB.setMemRefs(MMOBegin, MMOEnd);
+  // Jump
+  BuildMI(*MBB, MI, DL, TII->get(IJmpOpc)).addReg(Tmp);
+
+  MI->eraseFromParent();
+  return MBB;
+}
+
 MachineBasicBlock *
 X86TargetLowering::EmitInstrWithCustomInserter(MachineInstr *MI,
                                                MachineBasicBlock *BB) const {
@@ -13427,6 +13621,14 @@ X86TargetLowering::EmitInstrWithCustomInserter(MachineInstr *MI,
 
   case X86::VAARG_64:
     return EmitVAARG64WithCustomInserter(MI, BB);
+
+  case X86::EH_SjLj_SetJmp32:
+  case X86::EH_SjLj_SetJmp64:
+    return emitEHSjLjSetJmp(MI, BB);
+
+  case X86::EH_SjLj_LongJmp32:
+  case X86::EH_SjLj_LongJmp64:
+    return emitEHSjLjLongJmp(MI, BB);
   }
 }
 

lib/Target/X86/X86ISelLowering.h

@@ -217,6 +217,12 @@ namespace llvm {
       // EH_RETURN - Exception Handling helpers.
       EH_RETURN,
 
+      // EH_SJLJ_SETJMP - SjLj exception handling setjmp.
+      EH_SJLJ_SETJMP,
+
+      // EH_SJLJ_LONGJMP - SjLj exception handling longjmp.
+      EH_SJLJ_LONGJMP,
+
       /// TC_RETURN - Tail call return.
       ///   operand #0 chain
       ///   operand #1 callee (register or absolute)
@@ -810,6 +816,8 @@ namespace llvm {
     SDValue LowerFRAMEADDR(SDValue Op, SelectionDAG &DAG) const;
     SDValue LowerFRAME_TO_ARGS_OFFSET(SDValue Op, SelectionDAG &DAG) const;
     SDValue LowerEH_RETURN(SDValue Op, SelectionDAG &DAG) const;
+    SDValue lowerEH_SJLJ_SETJMP(SDValue Op, SelectionDAG &DAG) const;
+    SDValue lowerEH_SJLJ_LONGJMP(SDValue Op, SelectionDAG &DAG) const;
     SDValue LowerINIT_TRAMPOLINE(SDValue Op, SelectionDAG &DAG) const;
     SDValue LowerFLT_ROUNDS_(SDValue Op, SelectionDAG &DAG) const;
     SDValue LowerShift(SDValue Op, SelectionDAG &DAG) const;
@@ -906,6 +914,12 @@ namespace llvm {
     MachineBasicBlock *emitLoweredTLSAddr(MachineInstr *MI,
                                           MachineBasicBlock *BB) const;
 
+    MachineBasicBlock *emitEHSjLjSetJmp(MachineInstr *MI,
+                                        MachineBasicBlock *MBB) const;
+
+    MachineBasicBlock *emitEHSjLjLongJmp(MachineInstr *MI,
+                                         MachineBasicBlock *MBB) const;
+
     /// Emit nodes that will be selected as "test Op0,Op0", or something
     /// equivalent, for use with the given x86 condition code.
     SDValue EmitTest(SDValue Op0, unsigned X86CC, SelectionDAG &DAG) const;

lib/Target/X86/X86InstrCompiler.td

@@ -165,6 +165,33 @@ def EH_RETURN64   : I<0xC3, RawFrm, (outs), (ins GR64:$addr),
 
 }
 
+let hasSideEffects = 1, isBarrier = 1, isCodeGenOnly = 1,
+    usesCustomInserter = 1 in {
+  def EH_SjLj_SetJmp32  : I<0, Pseudo, (outs GR32:$dst), (ins i32mem:$buf),
+                            "#EH_SJLJ_SETJMP32",
+                            [(set GR32:$dst, (X86eh_sjlj_setjmp addr:$buf))]>,
+                          Requires<[In32BitMode]>;
+  def EH_SjLj_SetJmp64  : I<0, Pseudo, (outs GR32:$dst), (ins i64mem:$buf),
+                            "#EH_SJLJ_SETJMP64",
+                            [(set GR32:$dst, (X86eh_sjlj_setjmp addr:$buf))]>,
+                          Requires<[In64BitMode]>;
+  let isTerminator = 1 in {
+  def EH_SjLj_LongJmp32 : I<0, Pseudo, (outs), (ins i32mem:$buf),
+                            "#EH_SJLJ_LONGJMP32",
+                            [(X86eh_sjlj_longjmp addr:$buf)]>,
+                          Requires<[In32BitMode]>;
+  def EH_SjLj_LongJmp64 : I<0, Pseudo, (outs), (ins i64mem:$buf),
+                            "#EH_SJLJ_LONGJMP64",
+                            [(X86eh_sjlj_longjmp addr:$buf)]>,
+                          Requires<[In64BitMode]>;
+  }
+}
+
+let isBranch = 1, isTerminator = 1, isCodeGenOnly = 1 in {
+  def EH_SjLj_Setup : I<0, Pseudo, (outs), (ins brtarget:$dst),
+                        "#EH_SjLj_Setup\t$dst", []>;
+}
+
 //===----------------------------------------------------------------------===//
 // Pseudo instructions used by segmented stacks.
 //

lib/Target/X86/X86InstrInfo.td

@@ -216,6 +216,14 @@ def X86tlsbaseaddr : SDNode<"X86ISD::TLSBASEADDR", SDT_X86TLSBASEADDR,
 def X86ehret : SDNode<"X86ISD::EH_RETURN", SDT_X86EHRET,
                         [SDNPHasChain]>;
 
+def X86eh_sjlj_setjmp  : SDNode<"X86ISD::EH_SJLJ_SETJMP",
+                                SDTypeProfile<1, 1, [SDTCisInt<0>,
+                                                     SDTCisPtrTy<1>]>,
+                                [SDNPHasChain, SDNPSideEffect]>;
+def X86eh_sjlj_longjmp : SDNode<"X86ISD::EH_SJLJ_LONGJMP",
+                                SDTypeProfile<0, 1, [SDTCisPtrTy<0>]>,
+                                [SDNPHasChain, SDNPSideEffect]>;
+
 def X86tcret : SDNode<"X86ISD::TC_RETURN", SDT_X86TCRET,
                         [SDNPHasChain,  SDNPOptInGlue, SDNPVariadic]>;
 

lib/Target/X86/X86RegisterInfo.cpp

@@ -261,6 +261,11 @@ X86RegisterInfo::getCallPreservedMask(CallingConv::ID CC) const {
   return CSR_64_RegMask;
 }
 
+const uint32_t*
+X86RegisterInfo::getNoPreservedMask() const {
+  return CSR_NoRegs_RegMask;
+}
+
 BitVector X86RegisterInfo::getReservedRegs(const MachineFunction &MF) const {
   BitVector Reserved(getNumRegs());
   const TargetFrameLowering *TFI = MF.getTarget().getFrameLowering();

lib/Target/X86/X86RegisterInfo.h

@@ -100,6 +100,7 @@ public:
   /// callee-save registers on this target.
   const uint16_t *getCalleeSavedRegs(const MachineFunction* MF = 0) const;
   const uint32_t *getCallPreservedMask(CallingConv::ID) const;
+  const uint32_t *getNoPreservedMask() const;
 
   /// getReservedRegs - Returns a bitset indexed by physical register number
   /// indicating if a register is a special register that has particular uses and

test/CodeGen/X86/sjlj.ll

@@ -0,0 +1,46 @@
+; RUN: llc < %s -mtriple=i386-pc-linux -mcpu=corei7 -relocation-model=static | FileCheck --check-prefix=X86 %s
+; RUN: llc < %s -mtriple=x86_64-pc-linux -mcpu=corei7 | FileCheck --check-prefix=X64 %s
+
+@buf = internal global [5 x i8*] zeroinitializer
+
+declare i8* @llvm.frameaddress(i32) nounwind readnone
+
+declare i8* @llvm.stacksave() nounwind
+
+declare i32 @llvm.eh.sjlj.setjmp(i8*) nounwind
+
+declare void @llvm.eh.sjlj.longjmp(i8*) nounwind
+
+define i32 @sj0() nounwind {
+  %fp = tail call i8* @llvm.frameaddress(i32 0)
+  store i8* %fp, i8** getelementptr inbounds ([5 x i8*]* @buf, i64 0, i64 0), align 16
+  %sp = tail call i8* @llvm.stacksave()
+  store i8* %sp, i8** getelementptr inbounds ([5 x i8*]* @buf, i64 0, i64 2), align 16
+  %r = tail call i32 @llvm.eh.sjlj.setjmp(i8* bitcast ([5 x i8*]* @buf to i8*))
+  ret i32 %r
+; X86: sj0
+; x86: movl %ebp, buf
+; x86: movl ${{.*LBB.*}}, buf+4
+; X86: movl %esp, buf+8
+; X86: ret
+; X64: sj0
+; x64: movq %rbp, buf(%rip)
+; x64: movq ${{.*LBB.*}}, buf+8(%rip)
+; X64: movq %rsp, buf+16(%rip)
+; X64: ret
+}
+
+define void @lj0() nounwind {
+  tail call void @llvm.eh.sjlj.longjmp(i8* bitcast ([5 x i8*]* @buf to i8*))
+  unreachable
+; X86: lj0
+; X86: movl buf, %ebp
+; X86: movl buf+4, %[[REG32:.*]]
+; X86: movl buf+8, %esp
+; X86: jmpl *%[[REG32]]
+; X64: lj0
+; X64: movq buf(%rip), %rbp
+; X64: movq buf+8(%rip), %[[REG64:.*]]
+; X64: movq buf+16(%rip), %rsp
+; X64: jmpq *%[[REG64]]
+}