Fix __builtin_setjmp in combination with sjlj exception handling.

[MatzeB]

Summary

builtin_setjmp in combination with the sjlj exception handling style was broken. This was caused by the strange decision to produce exception handling dispatch jump tables upon seeing the setjmp instruction. This resulted in builtin_setjmp being broken on ARM because it tried to build those dispatch tables with no sjlj exception handling code being present.

Commit message: SJLJ exception handling expects the backends to emit dispatch jump
tables at the beginning of the function, we cannot reuse llvm.eh.sjlj.setjmp to trigger this effect or we get into trouble when __builtin_setjmp was used independently of exception handling.
To solve this issue a new llvm.eh.sjlj.setup_dispatch intrinsic is
introduces which is used instead of llvm.eh.sjlj.setjmp in the sjlj
exception handling style.

[MatzeB]

ping

[john.brawn]

Isn't llvm.eh.sjlj.setjmp specifically the intrinsic for sjlj exception-handling setjmp? In which case emitting the dispatch table when it's seen sounds reasonable. Intrinsics.td lists it under "Exception Handling Intrinsics".

Clang does generate llvm.eh.sjlj.setjmp for __builtin_setjmp, but that sounds more like a bug in clang to me.

[MatzeB]

The thing is eh_sjlj_longjmp was never used by llvms sjlj handling code and the implementation in the X86 target was for a __builtin_setjmp handling and would not have worked with llvms current sjlj exception handling code. So introducing a new intrinsic for eh_sjlj makes alot of sense.

As a followup I created http://reviews.llvm.org/D9589 which should make this obvious that they are used to implement builtin_setjmp and builtin_longjmp by renaming the intrinsics to lightweight_{setjmp|longjmp}.

[MatzeB]

ping

[MatzeB]

ping 2

[MatzeB]

Isn't llvm.eh.sjlj.setjmp specifically the intrinsic for sjlj exception-handling setjmp? In which case emitting the dispatch table > when it's seen sounds reasonable. Intrinsics.td lists it under "Exception Handling Intrinsics".

Clang does generate llvm.eh.sjlj.setjmp for __builtin_setjmp, but that sounds more like a bug in clang to me.

I just had a chat with Joerg on IRC as he objected my plan to simply rename sjlj.setjmp to something else. Apparently sjlj.setjmp/sjlj.longjmp are the right thing to use to implement builtin_setjmp and builtin_longjmp and in fact if you look at the SjLj runtime in libcxxabi you will find __builtin_longjmp being used to implement exactly this scheme.

So in short: I think it is expected and fine to use llvm.eh.sjlj.setjmp/llvm.ej.sjlj.longjmp to implement the builtins in clang. So I think the proposed change to split dispatch table setup into an own intrinsic is indeed reasonable.

[MatzeB]

ping

[MatzeB]

ping2

[MatzeB]

ping3

[MatzeB]

ping4

[compnerd]

LGTM, though it would be nice to have a test for an unsupported target as well (e.g. Linux).

llvm/trunk/include/llvm/CodeGen/ISDOpcodes.h

enum NodeType {
     EH_SJLJ_SETJMP,
 
     /// OUTCHAIN = EH_SJLJ_LONGJMP(INCHAIN, buffer)
     /// This corresponds to the eh.sjlj.longjmp intrinsic.
     /// It takes an input chain and a pointer to the jump buffer as inputs
     /// and returns an outchain.
     EH_SJLJ_LONGJMP,
 
+    /// OUTCHAIN = EH_SJLJ_SETUP_DISPATCH(INCHAIN)
+    /// The target initializes the dispatch table here.
+    EH_SJLJ_SETUP_DISPATCH,
+
     /// TargetConstant* - Like Constant*, but the DAG does not do any folding,
     /// simplification, or lowering of the constant. They are used for constants
     /// which are known to fit in the immediate fields of their users, or for
     /// carrying magic numbers which are not values which need to be
     /// materialized in registers.
     TargetConstant,
     TargetConstantFP,
 

llvm/trunk/include/llvm/IR/Intrinsics.td

 
 let Properties = [IntrNoMem] in {
   def int_eh_sjlj_lsda             : Intrinsic<[llvm_ptr_ty]>;
   def int_eh_sjlj_callsite         : Intrinsic<[], [llvm_i32_ty]>;
 }
 def int_eh_sjlj_functioncontext : Intrinsic<[], [llvm_ptr_ty]>;
 def int_eh_sjlj_setjmp          : Intrinsic<[llvm_i32_ty], [llvm_ptr_ty]>;
 def int_eh_sjlj_longjmp         : Intrinsic<[], [llvm_ptr_ty], [IntrNoReturn]>;
+def int_eh_sjlj_setup_dispatch  : Intrinsic<[], []>;
 
 //===---------------- Generic Variable Attribute Intrinsics----------------===//
 //
 def int_var_annotation : Intrinsic<[],
                                    [llvm_ptr_ty, llvm_ptr_ty,
                                     llvm_ptr_ty, llvm_i32_ty],
                                    [], "llvm.var.annotation">;
 def int_ptr_annotation : Intrinsic<[LLVMAnyPointerType<llvm_anyint_ty>],

llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp

#endif
   case ISD::EXTRACT_ELEMENT:
   case ISD::FLT_ROUNDS_:
   case ISD::FPOWI:
   case ISD::MERGE_VALUES:
   case ISD::EH_RETURN:
   case ISD::FRAME_TO_ARGS_OFFSET:
   case ISD::EH_SJLJ_SETJMP:
   case ISD::EH_SJLJ_LONGJMP:
+  case ISD::EH_SJLJ_SETUP_DISPATCH:
     // These operations lie about being legal: when they claim to be legal,
     // they should actually be expanded.
     Action = TLI.getOperationAction(Node->getOpcode(), Node->getValueType(0));
     if (Action == TargetLowering::Legal)
       Action = TargetLowering::Expand;
     break;
   case ISD::INIT_TRAMPOLINE:
   case ISD::ADJUST_TRAMPOLINE:

llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp

case Intrinsic::eh_sjlj_setjmp: {
     DAG.setRoot(Op.getValue(1));
     return nullptr;
   }
   case Intrinsic::eh_sjlj_longjmp: {
     DAG.setRoot(DAG.getNode(ISD::EH_SJLJ_LONGJMP, sdl, MVT::Other,
                             getRoot(), getValue(I.getArgOperand(0))));
     return nullptr;
   }
+  case Intrinsic::eh_sjlj_setup_dispatch: {
+    DAG.setRoot(DAG.getNode(ISD::EH_SJLJ_SETUP_DISPATCH, sdl, MVT::Other,
+                            getRoot()));
+    return nullptr;
+  }
 
   case Intrinsic::masked_gather:
     visitMaskedGather(I);
     return nullptr;
   case Intrinsic::masked_load:
     visitMaskedLoad(I);
     return nullptr;
   case Intrinsic::masked_scatter:

llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp

#endif
   case ISD::FRAMEADDR:                  return "FRAMEADDR";
   case ISD::LOCAL_RECOVER:        return "LOCAL_RECOVER";
   case ISD::READ_REGISTER:              return "READ_REGISTER";
   case ISD::WRITE_REGISTER:             return "WRITE_REGISTER";
   case ISD::FRAME_TO_ARGS_OFFSET:       return "FRAME_TO_ARGS_OFFSET";
   case ISD::EH_RETURN:                  return "EH_RETURN";
   case ISD::EH_SJLJ_SETJMP:             return "EH_SJLJ_SETJMP";
   case ISD::EH_SJLJ_LONGJMP:            return "EH_SJLJ_LONGJMP";
+  case ISD::EH_SJLJ_SETUP_DISPATCH:     return "EH_SJLJ_SETUP_DISPATCH";
   case ISD::ConstantPool:               return "ConstantPool";
   case ISD::TargetIndex:                return "TargetIndex";
   case ISD::ExternalSymbol:             return "ExternalSymbol";
   case ISD::BlockAddress:               return "BlockAddress";
   case ISD::INTRINSIC_WO_CHAIN:
   case ISD::INTRINSIC_VOID:
   case ISD::INTRINSIC_W_CHAIN: {
     unsigned OpNo = getOpcode() == ISD::INTRINSIC_WO_CHAIN ? 0 : 1;

llvm/trunk/lib/CodeGen/SjLjEHPrepare.cpp

 
 namespace {
 class SjLjEHPrepare : public FunctionPass {
   Type *doubleUnderDataTy;
   Type *doubleUnderJBufTy;
   Type *FunctionContextTy;
   Constant *RegisterFn;
   Constant *UnregisterFn;
-  Constant *BuiltinSetjmpFn;
+  Constant *BuiltinSetupDispatchFn;
   Constant *FrameAddrFn;
   Constant *StackAddrFn;
   Constant *StackRestoreFn;
   Constant *LSDAAddrFn;
   Value *PersonalityFn;
   Constant *CallSiteFn;
   Constant *FuncCtxFn;
   AllocaInst *FuncCtx;
RegisterFn = M.getOrInsertFunction(
       "_Unwind_SjLj_Register", Type::getVoidTy(M.getContext()),
       PointerType::getUnqual(FunctionContextTy), (Type *)nullptr);
   UnregisterFn = M.getOrInsertFunction(
       "_Unwind_SjLj_Unregister", Type::getVoidTy(M.getContext()),
       PointerType::getUnqual(FunctionContextTy), (Type *)nullptr);
   FrameAddrFn = Intrinsic::getDeclaration(&M, Intrinsic::frameaddress);
   StackAddrFn = Intrinsic::getDeclaration(&M, Intrinsic::stacksave);
   StackRestoreFn = Intrinsic::getDeclaration(&M, Intrinsic::stackrestore);
-  BuiltinSetjmpFn = Intrinsic::getDeclaration(&M, Intrinsic::eh_sjlj_setjmp);
+  BuiltinSetupDispatchFn =
+    Intrinsic::getDeclaration(&M, Intrinsic::eh_sjlj_setup_dispatch);
   LSDAAddrFn = Intrinsic::getDeclaration(&M, Intrinsic::eh_sjlj_lsda);
   CallSiteFn = Intrinsic::getDeclaration(&M, Intrinsic::eh_sjlj_callsite);
   FuncCtxFn = Intrinsic::getDeclaration(&M, Intrinsic::eh_sjlj_functioncontext);
   PersonalityFn = nullptr;
 
   return true;
 }
 
bool SjLjEHPrepare::setupEntryBlockAndCallSites(Function &F) {
 
   // Save the stack pointer.
   Value *StackPtr = Builder.CreateConstGEP2_32(doubleUnderJBufTy, JBufPtr, 0, 2,
                                                "jbuf_sp_gep");
 
   Val = Builder.CreateCall(StackAddrFn, {}, "sp");
   Builder.CreateStore(Val, StackPtr, /*isVolatile=*/true);
 
-  // Call the setjmp instrinsic. It fills in the rest of the jmpbuf.
-  Value *SetjmpArg = Builder.CreateBitCast(JBufPtr, Builder.getInt8PtrTy());
-  Builder.CreateCall(BuiltinSetjmpFn, SetjmpArg);
+  // Call the setup_dispatch instrinsic. It fills in the rest of the jmpbuf.
+  Builder.CreateCall(BuiltinSetupDispatchFn, {});
 
   // Store a pointer to the function context so that the back-end will know
   // where to look for it.
   Value *FuncCtxArg = Builder.CreateBitCast(FuncCtx, Builder.getInt8PtrTy());
   Builder.CreateCall(FuncCtxFn, FuncCtxArg);
 
   // At this point, we are all set up, update the invoke instructions to mark
   // their call_site values.

llvm/trunk/lib/Target/ARM/ARMISelLowering.h

enum NodeType : unsigned {
       SUBC,         // Sub with carry
       SUBE,         // Sub using carry
 
       VMOVRRD,      // double to two gprs.
       VMOVDRR,      // Two gprs to double.
 
       EH_SJLJ_SETJMP,         // SjLj exception handling setjmp.
       EH_SJLJ_LONGJMP,        // SjLj exception handling longjmp.
+      EH_SJLJ_SETUP_DISPATCH, // SjLj exception handling setup_dispatch.
 
       TC_RETURN,    // Tail call return pseudo.
 
       THREAD_POINTER,
 
       DYN_ALLOC,    // Dynamic allocation on the stack.
 
       MEMBARRIER_MCR, // Memory barrier (MCR)
private:
     CCAssignFn *CCAssignFnForNode(CallingConv::ID CC, bool Return,
                                   bool isVarArg) const;
     SDValue LowerMemOpCallTo(SDValue Chain, SDValue StackPtr, SDValue Arg,
                              SDLoc dl, SelectionDAG &DAG,
                              const CCValAssign &VA,
                              ISD::ArgFlagsTy Flags) const;
     SDValue LowerEH_SJLJ_SETJMP(SDValue Op, SelectionDAG &DAG) const;
     SDValue LowerEH_SJLJ_LONGJMP(SDValue Op, SelectionDAG &DAG) const;
+    SDValue LowerEH_SJLJ_SETUP_DISPATCH(SDValue Op, SelectionDAG &DAG) const;
     SDValue LowerINTRINSIC_WO_CHAIN(SDValue Op, SelectionDAG &DAG,
                                     const ARMSubtarget *Subtarget) const;
     SDValue LowerBlockAddress(SDValue Op, SelectionDAG &DAG) const;
     SDValue LowerGlobalAddressDarwin(SDValue Op, SelectionDAG &DAG) const;
     SDValue LowerGlobalAddressELF(SDValue Op, SelectionDAG &DAG) const;
     SDValue LowerGlobalAddressWindows(SDValue Op, SelectionDAG &DAG) const;
     SDValue LowerGlobalTLSAddress(SDValue Op, SelectionDAG &DAG) const;
     SDValue LowerToTLSGeneralDynamicModel(GlobalAddressSDNode *GA,

llvm/trunk/lib/Target/ARM/ARMISelLowering.cpp

if (!Subtarget->useSoftFloat() && Subtarget->hasVFP2() &&
     // Turn f64->i64 into VMOVRRD, i64 -> f64 to VMOVDRR
     // iff target supports vfp2.
     setOperationAction(ISD::BITCAST, MVT::i64, Custom);
     setOperationAction(ISD::FLT_ROUNDS_, MVT::i32, Custom);
   }
 
   // We want to custom lower some of our intrinsics.
   setOperationAction(ISD::INTRINSIC_WO_CHAIN, MVT::Other, Custom);
-  if (Subtarget->isTargetDarwin()) {
-    setOperationAction(ISD::EH_SJLJ_SETJMP, MVT::i32, Custom);
-    setOperationAction(ISD::EH_SJLJ_LONGJMP, MVT::Other, Custom);
+  setOperationAction(ISD::EH_SJLJ_SETUP_DISPATCH, MVT::Other, Custom);
+  if (Subtarget->isTargetDarwin())
     setLibcallName(RTLIB::UNWIND_RESUME, "_Unwind_SjLj_Resume");
-  }
 
   setOperationAction(ISD::SETCC,     MVT::i32, Expand);
   setOperationAction(ISD::SETCC,     MVT::f32, Expand);
   setOperationAction(ISD::SETCC,     MVT::f64, Expand);
   setOperationAction(ISD::SELECT,    MVT::i32, Custom);
   setOperationAction(ISD::SELECT,    MVT::f32, Custom);
   setOperationAction(ISD::SELECT,    MVT::f64, Custom);
   setOperationAction(ISD::SELECT_CC, MVT::i32, Custom);
const char *ARMTargetLowering::getTargetNodeName(unsigned Opcode) const {
   case ARMISD::ADDE:          return "ARMISD::ADDE";
   case ARMISD::SUBC:          return "ARMISD::SUBC";
   case ARMISD::SUBE:          return "ARMISD::SUBE";
 
   case ARMISD::VMOVRRD:       return "ARMISD::VMOVRRD";
   case ARMISD::VMOVDRR:       return "ARMISD::VMOVDRR";
 
   case ARMISD::EH_SJLJ_SETJMP: return "ARMISD::EH_SJLJ_SETJMP";
-  case ARMISD::EH_SJLJ_LONGJMP:return "ARMISD::EH_SJLJ_LONGJMP";
+  case ARMISD::EH_SJLJ_LONGJMP: return "ARMISD::EH_SJLJ_LONGJMP";
+  case ARMISD::EH_SJLJ_SETUP_DISPATCH: return "ARMISD::EH_SJLJ_SETUP_DISPATCH";
 
   case ARMISD::TC_RETURN:     return "ARMISD::TC_RETURN";
 
   case ARMISD::THREAD_POINTER:return "ARMISD::THREAD_POINTER";
 
   case ARMISD::DYN_ALLOC:     return "ARMISD::DYN_ALLOC";
 
   case ARMISD::MEMBARRIER_MCR: return "ARMISD::MEMBARRIER_MCR";

 
 SDValue
 ARMTargetLowering::LowerEH_SJLJ_LONGJMP(SDValue Op, SelectionDAG &DAG) const {
   SDLoc dl(Op);
   return DAG.getNode(ARMISD::EH_SJLJ_LONGJMP, dl, MVT::Other, Op.getOperand(0),
                      Op.getOperand(1), DAG.getConstant(0, dl, MVT::i32));
 }
 
+SDValue ARMTargetLowering::LowerEH_SJLJ_SETUP_DISPATCH(SDValue Op,
+                                                      SelectionDAG &DAG) const {
+  SDLoc dl(Op);
+  return DAG.getNode(ARMISD::EH_SJLJ_SETUP_DISPATCH, dl, MVT::Other,
+                     Op.getOperand(0));
+}
+
 SDValue
 ARMTargetLowering::LowerINTRINSIC_WO_CHAIN(SDValue Op, SelectionDAG &DAG,
                                           const ARMSubtarget *Subtarget) const {
   unsigned IntNo = cast<ConstantSDNode>(Op.getOperand(0))->getZExtValue();
   SDLoc dl(Op);
   switch (IntNo) {
   default: return SDValue();    // Don't custom lower most intrinsics.
   case Intrinsic::arm_rbit: {
SDValue ARMTargetLowering::LowerOperation(SDValue Op, SelectionDAG &DAG) const {
   case ISD::FP_TO_SINT:
   case ISD::FP_TO_UINT:    return LowerFP_TO_INT(Op, DAG);
   case ISD::FCOPYSIGN:     return LowerFCOPYSIGN(Op, DAG);
   case ISD::RETURNADDR:    return LowerRETURNADDR(Op, DAG);
   case ISD::FRAMEADDR:     return LowerFRAMEADDR(Op, DAG);
   case ISD::GLOBAL_OFFSET_TABLE: return LowerGLOBAL_OFFSET_TABLE(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::EH_SJLJ_SETUP_DISPATCH: return LowerEH_SJLJ_SETUP_DISPATCH(Op, DAG);
   case ISD::INTRINSIC_WO_CHAIN: return LowerINTRINSIC_WO_CHAIN(Op, DAG,
                                                                Subtarget);
   case ISD::BITCAST:       return ExpandBITCAST(Op.getNode(), DAG);
   case ISD::SHL:
   case ISD::SRL:
   case ISD::SRA:           return LowerShift(Op.getNode(), DAG, Subtarget);
   case ISD::SHL_PARTS:     return LowerShiftLeftParts(Op, DAG);
   case ISD::SRL_PARTS:
case ARM::BCCZi64: {
     return BB;
   }
 
   case ARM::Int_eh_sjlj_setjmp:
   case ARM::Int_eh_sjlj_setjmp_nofp:
   case ARM::tInt_eh_sjlj_setjmp:
   case ARM::t2Int_eh_sjlj_setjmp:
   case ARM::t2Int_eh_sjlj_setjmp_nofp:
+    return BB;
+
+  case ARM::Int_eh_sjlj_setup_dispatch:
     EmitSjLjDispatchBlock(MI, BB);
     return BB;
 
   case ARM::ABS:
   case ARM::t2ABS: {
     // To insert an ABS instruction, we have to insert the
     // diamond control-flow pattern.  The incoming instruction knows the
     // source vreg to test against 0, the destination vreg to set,

llvm/trunk/lib/Target/ARM/ARMInstrInfo.td

 
 def SDT_ARMPICAdd  : SDTypeProfile<1, 2, [SDTCisSameAs<0, 1>,
                                           SDTCisPtrTy<1>, SDTCisVT<2, i32>]>;
 
 def SDT_ARMThreadPointer : SDTypeProfile<1, 0, [SDTCisPtrTy<0>]>;
 def SDT_ARMEH_SJLJ_Setjmp : SDTypeProfile<1, 2, [SDTCisInt<0>, SDTCisPtrTy<1>,
                                                  SDTCisInt<2>]>;
 def SDT_ARMEH_SJLJ_Longjmp: SDTypeProfile<0, 2, [SDTCisPtrTy<0>, SDTCisInt<1>]>;
+def SDT_ARMEH_SJLJ_SetupDispatch: SDTypeProfile<0, 0, []>;
 
 def SDT_ARMMEMBARRIER     : SDTypeProfile<0, 1, [SDTCisInt<0>]>;
 
 def SDT_ARMPREFETCH : SDTypeProfile<0, 3, [SDTCisPtrTy<0>, SDTCisSameAs<1, 2>,
                                            SDTCisInt<1>]>;
 
 def SDT_ARMTCRET : SDTypeProfile<0, 1, [SDTCisPtrTy<0>]>;
 

 
 def ARMthread_pointer: SDNode<"ARMISD::THREAD_POINTER", SDT_ARMThreadPointer>;
 def ARMeh_sjlj_setjmp: SDNode<"ARMISD::EH_SJLJ_SETJMP",
                                SDT_ARMEH_SJLJ_Setjmp,
                                [SDNPHasChain, SDNPSideEffect]>;
 def ARMeh_sjlj_longjmp: SDNode<"ARMISD::EH_SJLJ_LONGJMP",
                                SDT_ARMEH_SJLJ_Longjmp,
                                [SDNPHasChain, SDNPSideEffect]>;
+def ARMeh_sjlj_setup_dispatch: SDNode<"ARMISD::EH_SJLJ_SETUP_DISPATCH",
+                                      SDT_ARMEH_SJLJ_SetupDispatch,
+                                      [SDNPHasChain, SDNPSideEffect]>;
 
 def ARMMemBarrierMCR  : SDNode<"ARMISD::MEMBARRIER_MCR", SDT_ARMMEMBARRIER,
                                [SDNPHasChain, SDNPSideEffect]>;
 def ARMPreload        : SDNode<"ARMISD::PRELOAD", SDT_ARMPREFETCH,
                                [SDNPHasChain, SDNPMayLoad, SDNPMayStore]>;
 
 def ARMrbit          : SDNode<"ARMISD::RBIT", SDTIntUnaryOp>;
 

 let isBarrier = 1, hasSideEffects = 1, isTerminator = 1,
     Defs = [ R7, LR, SP ] in {
 def Int_eh_sjlj_longjmp : PseudoInst<(outs), (ins GPR:$src, GPR:$scratch),
                              NoItinerary,
                          [(ARMeh_sjlj_longjmp GPR:$src, GPR:$scratch)]>,
                                 Requires<[IsARM]>;
 }
 
+let isBarrier = 1, hasSideEffects = 1, usesCustomInserter = 1 in
+def Int_eh_sjlj_setup_dispatch : PseudoInst<(outs), (ins), NoItinerary,
+            [(ARMeh_sjlj_setup_dispatch)]>;
+
 // eh.sjlj.dispatchsetup pseudo-instruction.
 // This pseudo is used for both ARM and Thumb. Any differences are handled when
 // the pseudo is expanded (which happens before any passes that need the
 // instruction size).
 let isBarrier = 1 in
 def Int_eh_sjlj_dispatchsetup : PseudoInst<(outs), (ins), NoItinerary, []>;
 
 

llvm/trunk/test/CodeGen/ARM/setjmp_longjmp.ll

+; RUN: llc %s -o - | FileCheck %s
+target triple = "armv7-apple-ios"
+
+declare i32 @llvm.eh.sjlj.setjmp(i8*)
+declare void @llvm.eh.sjlj.longjmp(i8*)
+@g = external global i32
+
+declare void @may_throw()
+declare i32 @__gxx_personality_sj0(...)
+declare i8* @__cxa_begin_catch(i8*)
+declare void @__cxa_end_catch()
+declare i32 @llvm.eh.typeid.for(i8*)
+declare i8* @llvm.frameaddress(i32)
+declare i8* @llvm.stacksave()
+@_ZTIPKc = external constant i8*
+
+; CHECK-LABEL: foobar
+;
+; setjmp sequence:
+; CHECK: add [[PCREG:r[0-9]+]], pc, #8
+; CHECK-NEXT: str [[PCREG]], {{\[}}[[BUFREG:r[0-9]+]], #4]
+; CHECK-NEXT: mov r0, #0
+; CHECK-NEXT: add pc, pc, #0
+; CHECK-NEXT: mov r0, #1
+;
+; longjmp sequence:
+; CHECK: ldr sp, [{{\s*}}[[BUFREG:r[0-9]+]], #8]
+; CHECK-NEXT: ldr [[DESTREG:r[0-9]+]], {{\[}}[[BUFREG]], #4]
+; CHECK-NEXT: ldr r7, {{\[}}[[BUFREG]]{{\]}}
+; CHECK-NEXT: bx [[DESTREG]]
+define void @foobar() {
+entry:
+  %buf = alloca [5 x i8*], align 4
+  %arraydecay = getelementptr inbounds [5 x i8*], [5 x i8*]* %buf, i32 0, i32 0
+  %bufptr = bitcast i8** %arraydecay to i8*
+  ; Note: This is simplified, in reality you have to store the framepointer +
+  ; stackpointer in the buffer as well for this to be legal!
+  %setjmpres = call i32 @llvm.eh.sjlj.setjmp(i8* %bufptr)
+  %tobool = icmp ne i32 %setjmpres, 0
+  br i1 %tobool, label %if.then, label %if.else
+
+if.then:
+  store volatile i32 1, i32* @g, align 4
+  br label %if.end
+
+if.else:
+  store volatile i32 0, i32* @g, align 4
+  call void @llvm.eh.sjlj.longjmp(i8* %bufptr)
+  unreachable
+
+if.end:
+  ret void
+}
+
+; CHECK-LABEL: combine_sjlj_eh_and_setjmp_longjmp
+; Check that we can mix sjlj exception handling with __builtin_setjmp
+; and __builtin_longjmp.
+;
+; setjmp sequence:
+; CHECK: add [[PCREG:r[0-9]+]], pc, #8
+; CHECK-NEXT: str [[PCREG]], {{\[}}[[BUFREG:r[0-9]+]], #4]
+; CHECK-NEXT: mov r0, #0
+; CHECK-NEXT: add pc, pc, #0
+; CHECK-NEXT: mov r0, #1
+;
+; longjmp sequence:
+; CHECK: ldr sp, [{{\s*}}[[BUFREG:r[0-9]+]], #8]
+; CHECK-NEXT: ldr [[DESTREG:r[0-9]+]], {{\[}}[[BUFREG]], #4]
+; CHECK-NEXT: ldr r7, {{\[}}[[BUFREG]]{{\]}}
+; CHECK-NEXT: bx [[DESTREG]]
+define void @combine_sjlj_eh_and_setjmp_longjmp() personality i8* bitcast (i32 (...)* @__gxx_personality_sj0 to i8*) {
+entry:
+  %buf = alloca [5 x i8*], align 4
+  invoke void @may_throw() to label %try.cont unwind label %lpad
+
+lpad:
+  %0 = landingpad { i8*, i32 } catch i8* bitcast (i8** @_ZTIPKc to i8*)
+  %1 = extractvalue { i8*, i32 } %0, 1
+  %2 = tail call i32 @llvm.eh.typeid.for(i8* bitcast (i8** @_ZTIPKc to i8*)) #3
+  %matches = icmp eq i32 %1, %2
+  br i1 %matches, label %catch, label %eh.resume
+
+catch:
+  %3 = extractvalue { i8*, i32 } %0, 0
+  %4 = tail call i8* @__cxa_begin_catch(i8* %3) #3
+  store volatile i32 0, i32* @g, align 4
+  %5 = bitcast [5 x i8*]* %buf to i8*
+  %arraydecay = getelementptr inbounds [5 x i8*], [5 x i8*]* %buf, i64 0, i64 0
+  %6 = tail call i8* @llvm.frameaddress(i32 0)
+  store i8* %6, i8** %arraydecay, align 16
+  %7 = tail call i8* @llvm.stacksave()
+  %8 = getelementptr [5 x i8*], [5 x i8*]* %buf, i64 0, i64 2
+  store i8* %7, i8** %8, align 16
+  %9 = call i32 @llvm.eh.sjlj.setjmp(i8* %5)
+  %tobool = icmp eq i32 %9, 0
+  br i1 %tobool, label %if.else, label %if.then
+
+if.then:
+  store volatile i32 2, i32* @g, align 4
+  call void @__cxa_end_catch() #3
+  br label %try.cont
+
+if.else:
+  store volatile i32 1, i32* @g, align 4
+  call void @llvm.eh.sjlj.longjmp(i8* %5)
+  unreachable
+
+eh.resume:
+  resume { i8*, i32 } %0
+
+try.cont:
+  ret void
+}