Fix __builtin_setjmp in combination with sjlj exception handling.

llvm.eh.sjlj.setjmp was used as part of the SjLj exception handling
style but is also used in clang to implement __builtin_setjmp.  The ARM
backend needs to output additional dispatch tables for the SjLj
exception handling style, these tables however can't be emitted if
llvm.eh.sjlj.setjmp is simply used for __builtin_setjmp and no actual
landing pad blocks exist.

To solve this issue a new llvm.eh.sjlj.setup_dispatch intrinsic is
introduced which is used instead of llvm.eh.sjlj.setjmp in the SjLj
exception handling lowering, so we can differentiate between the case
where we actually need to setup a dispatch table and the case where we
just need the __builtin_setjmp semantic.

Differential Revision: http://reviews.llvm.org/D9313

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@242481 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/llvm/CodeGen/ISDOpcodes.h b/include/llvm/CodeGen/ISDOpcodes.h
index 8a4b779f03ab77ff8e873774d04f22aa7de28e86..49c002bf5f4275308c009dd6aad8349e4f8047df 100644 (file)
--- a/include/llvm/CodeGen/ISDOpcodes.h
+++ b/include/llvm/CodeGen/ISDOpcodes.h
@@ -108,6 +108,10 @@ namespace ISD {
     /// 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

diff --git a/include/llvm/IR/Intrinsics.td b/include/llvm/IR/Intrinsics.td
index af312be186c0fbdc4f655fb11318bb2aa1a0a195..83cfebe5b33b8f793a6a8731a5f26739413ed266 100644 (file)
--- a/include/llvm/IR/Intrinsics.td
+++ b/include/llvm/IR/Intrinsics.td
@@ -455,6 +455,7 @@ let Properties = [IntrNoMem] in {
 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----------------===//
 //

diff --git a/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp b/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
index 51057a0fecb7144ad66a17085ab9c7c22cf50184..0396736ad819be08bf0d8ab7cff9853439d320e1 100644 (file)
--- a/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
@@ -1264,6 +1264,7 @@ void SelectionDAGLegalize::LegalizeOp(SDNode *Node) {
   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));

diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index 73de6e3cfbdb42df9fbe7c2af7a9dd38b4ded8f7..702e14bbcc3c21f6928ac5b2ab4a813b54bc00ff 100644 (file)
--- a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -4410,6 +4410,11 @@ SelectionDAGBuilder::visitIntrinsicCall(const CallInst &I, unsigned Intrinsic) {
                             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);

diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp
index 8dabddc642bcf4214930652260bdc7ab4a268b83..883cc2573a67de0ed961dbf2f3f741a53ae109e2 100644 (file)
--- a/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp
@@ -102,6 +102,7 @@ std::string SDNode::getOperationName(const SelectionDAG *G) const {
   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";

diff --git a/lib/CodeGen/SjLjEHPrepare.cpp b/lib/CodeGen/SjLjEHPrepare.cpp
index d236e1f5ab6fb6379bad03bd566968551be03554..2a16b649395c8a8d496a41b5e88d5f9c92098a83 100644 (file)
--- a/lib/CodeGen/SjLjEHPrepare.cpp
+++ b/lib/CodeGen/SjLjEHPrepare.cpp
@@ -50,7 +50,7 @@ class SjLjEHPrepare : public FunctionPass {
   Type *FunctionContextTy;
   Constant *RegisterFn;
   Constant *UnregisterFn;
-  Constant *BuiltinSetjmpFn;
+  Constant *BuiltinSetupDispatchFn;
   Constant *FrameAddrFn;
   Constant *StackAddrFn;
   Constant *StackRestoreFn;
@@ -112,7 +112,8 @@ bool SjLjEHPrepare::doInitialization(Module &M) {
   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);
@@ -421,9 +422,8 @@ bool SjLjEHPrepare::setupEntryBlockAndCallSites(Function &F) {
   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.

diff --git a/lib/Target/ARM/ARMISelLowering.cpp b/lib/Target/ARM/ARMISelLowering.cpp
index e335784f6d876cf742e6da081b1bd049cce8da3e..0a5d8833c069305d6786d8ab4a9cc48cb0e24a9d 100644 (file)
--- a/lib/Target/ARM/ARMISelLowering.cpp
+++ b/lib/Target/ARM/ARMISelLowering.cpp
@@ -849,11 +849,11 @@ ARMTargetLowering::ARMTargetLowering(const TargetMachine &TM,
 
   // 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_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);
@@ -1069,7 +1069,8 @@ const char *ARMTargetLowering::getTargetNodeName(unsigned Opcode) const {
   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";
 
@@ -2722,6 +2723,13 @@ ARMTargetLowering::LowerEH_SJLJ_LONGJMP(SDValue Op, SelectionDAG &DAG) const {
                      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 {
@@ -6573,6 +6581,7 @@ SDValue ARMTargetLowering::LowerOperation(SDValue Op, SelectionDAG &DAG) const {
   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);
@@ -7735,6 +7744,9 @@ ARMTargetLowering::EmitInstrWithCustomInserter(MachineInstr *MI,
   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;
 

diff --git a/lib/Target/ARM/ARMISelLowering.h b/lib/Target/ARM/ARMISelLowering.h
index efc9020c193a1af5d76cf10c693e26cd87d9b025..9d66be077ad5139ee631eebce265e00ba1e3a74f 100644 (file)
--- a/lib/Target/ARM/ARMISelLowering.h
+++ b/lib/Target/ARM/ARMISelLowering.h
@@ -79,6 +79,7 @@ namespace llvm {
 
       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.
 
@@ -496,6 +497,7 @@ namespace llvm {
                              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;

diff --git a/lib/Target/ARM/ARMInstrInfo.td b/lib/Target/ARM/ARMInstrInfo.td
index 61c45af26fe1e22e9e58a0b32b84e66cb7b7e00c..ded5533c130c532bcffaf7a5fe76bfbe8b651c40 100644 (file)
--- a/lib/Target/ARM/ARMInstrInfo.td
+++ b/lib/Target/ARM/ARMInstrInfo.td
@@ -59,6 +59,7 @@ 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>]>;
 
@@ -163,6 +164,9 @@ def ARMeh_sjlj_setjmp: SDNode<"ARMISD::EH_SJLJ_SETJMP",
 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]>;
@@ -5301,6 +5305,10 @@ def Int_eh_sjlj_longjmp : PseudoInst<(outs), (ins 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

diff --git a/test/CodeGen/ARM/setjmp_longjmp.ll b/test/CodeGen/ARM/setjmp_longjmp.ll
new file mode 100644 (file)
index 0000000..7100175
--- /dev/null
+++ b/test/CodeGen/ARM/setjmp_longjmp.ll
@@ -0,0 +1,113 @@
+; 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
+}