[WinEH] Don't emit CATCHRET from visitCatchPad

Instead, emit a CATCHPAD node which will get selected to a target
specific sequence.

llvm-svn: 252528

4 files changed, 32 insertions, 22 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index 60b06b4ab0e..5090bfbfb14 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -1178,7 +1178,6 @@ SDValue SelectionDAGBuilder::getValueImpl(const Value *V) {
 void SelectionDAGBuilder::visitCatchPad(const CatchPadInst &I) {
   auto Pers = classifyEHPersonality(FuncInfo.Fn->getPersonalityFn());
   bool IsMSVCCXX = Pers == EHPersonality::MSVC_CXX;
-  bool IsSEH = isAsynchronousEHPersonality(Pers);
   bool IsCoreCLR = Pers == EHPersonality::CoreCLR;
   MachineBasicBlock *CatchPadMBB = FuncInfo.MBB;
   // In MSVC C++ and CoreCLR, catchblocks are funclets and need prologues.
@@ -1190,22 +1189,16 @@ void SelectionDAGBuilder::visitCatchPad(const CatchPadInst &I) {
   // Update machine-CFG edge.
   FuncInfo.MBB->addSuccessor(NormalDestMBB);
 
-  // CatchPads in SEH are not funclets, they are merely markers which indicate
-  // where to insert register restoration code.
-  if (IsSEH) {
-    DAG.setRoot(DAG.getNode(ISD::CATCHRET, getCurSDLoc(), MVT::Other,
-                            getControlRoot(), DAG.getBasicBlock(NormalDestMBB),
-                            DAG.getBasicBlock(&FuncInfo.MF->front())));
-    return;
-  }
+  SDValue Chain =
+      DAG.getNode(ISD::CATCHPAD, getCurSDLoc(), MVT::Other, getControlRoot());
 
   // If this is not a fall-through branch or optimizations are switched off,
   // emit the branch.
   if (NormalDestMBB != NextBlock(CatchPadMBB) ||
       TM.getOptLevel() == CodeGenOpt::None)
-    DAG.setRoot(DAG.getNode(ISD::BR, getCurSDLoc(), MVT::Other,
-                            getControlRoot(),
-                            DAG.getBasicBlock(NormalDestMBB)));
+    Chain = DAG.getNode(ISD::BR, getCurSDLoc(), MVT::Other, Chain,
+                        DAG.getBasicBlock(NormalDestMBB));
+  DAG.setRoot(Chain);
 }
 
 void SelectionDAGBuilder::visitCatchRet(const CatchReturnInst &I) {
diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index 8d7712d3cd0..f5b38b39696 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -21401,15 +21401,7 @@ X86TargetLowering::EmitLoweredCatchRet(MachineInstr *MI,
   MachineBasicBlock *TargetMBB = MI->getOperand(0).getMBB();
   DebugLoc DL = MI->getDebugLoc();
 
-  // SEH does not outline catch bodies into funclets. Turn CATCHRETs into
-  // JMP_4s, possibly with some extra restoration code for 32-bit EH.
-  if (IsSEH) {
-    if (Subtarget->is32Bit())
-      BuildMI(*BB, MI, DL, TII.get(X86::EH_RESTORE));
-    BuildMI(*BB, MI, DL, TII.get(X86::JMP_4)).addMBB(TargetMBB);
-    MI->eraseFromParent();
-    return BB;
-  }
+  assert(!IsSEH && "SEH does not use catchret!");
 
   // Only 32-bit EH needs to worry about manually restoring stack pointers.
   if (!Subtarget->is32Bit())
@@ -21432,6 +21424,22 @@ X86TargetLowering::EmitLoweredCatchRet(MachineInstr *MI,
 }
 
 MachineBasicBlock *
+X86TargetLowering::EmitLoweredCatchPad(MachineInstr *MI,
+                                       MachineBasicBlock *BB) const {
+  MachineFunction *MF = BB->getParent();
+  const Constant *PerFn = MF->getFunction()->getPersonalityFn();
+  bool IsSEH = isAsynchronousEHPersonality(classifyEHPersonality(PerFn));
+  // Only 32-bit SEH requires special handling for catchpad.
+  if (IsSEH && Subtarget->is32Bit()) {
+    const TargetInstrInfo &TII = *Subtarget->getInstrInfo();
+    DebugLoc DL = MI->getDebugLoc();
+    BuildMI(*BB, MI, DL, TII.get(X86::EH_RESTORE));
+  }
+  MI->eraseFromParent();
+  return BB;
+}
+
+MachineBasicBlock *
 X86TargetLowering::EmitLoweredTLSCall(MachineInstr *MI,
                                       MachineBasicBlock *BB) const {
   // This is pretty easy.  We're taking the value that we received from
@@ -21813,6 +21821,8 @@ X86TargetLowering::EmitInstrWithCustomInserter(MachineInstr *MI,
     return EmitLoweredWinAlloca(MI, BB);
   case X86::CATCHRET:
     return EmitLoweredCatchRet(MI, BB);
+  case X86::CATCHPAD:
+    return EmitLoweredCatchPad(MI, BB);
   case X86::SEG_ALLOCA_32:
   case X86::SEG_ALLOCA_64:
     return EmitLoweredSegAlloca(MI, BB);
diff --git a/llvm/lib/Target/X86/X86ISelLowering.h b/llvm/lib/Target/X86/X86ISelLowering.h
index e7dbaa995c8..c800f16489b 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.h
+++ b/llvm/lib/Target/X86/X86ISelLowering.h
@@ -1101,6 +1101,9 @@ namespace llvm {
     MachineBasicBlock *EmitLoweredCatchRet(MachineInstr *MI,
                                            MachineBasicBlock *BB) const;
 
+    MachineBasicBlock *EmitLoweredCatchPad(MachineInstr *MI,
+                                           MachineBasicBlock *BB) const;
+
     MachineBasicBlock *EmitLoweredSegAlloca(MachineInstr *MI,
                                             MachineBasicBlock *BB) const;
 
diff --git a/llvm/lib/Target/X86/X86InstrCompiler.td b/llvm/lib/Target/X86/X86InstrCompiler.td
index f35fd5c1388..e6141ade92b 100644
--- a/llvm/lib/Target/X86/X86InstrCompiler.td
+++ b/llvm/lib/Target/X86/X86InstrCompiler.td
@@ -156,13 +156,17 @@ let isTerminator = 1, hasSideEffects = 1, isBarrier = 1, hasCtrlDep = 1,
     isCodeGenOnly = 1, isReturn = 1 in {
   def CLEANUPRET : I<0, Pseudo, (outs), (ins), "# CLEANUPRET", [(cleanupret)]>;
 
-  // CATCHRET needs a custom inserter for SEH nonsense.
+  // CATCHRET needs a custom inserter for SEH.
   let usesCustomInserter = 1 in
     def CATCHRET : I<0, Pseudo, (outs), (ins brtarget32:$dst, brtarget32:$from),
                      "# CATCHRET",
                      [(catchret bb:$dst, bb:$from)]>;
 }
 
+let hasSideEffects = 1, isBarrier = 1, hasCtrlDep = 1, isCodeGenOnly = 1,
+    usesCustomInserter = 1 in
+def CATCHPAD : I<0, Pseudo, (outs), (ins), "# CATCHPAD", [(catchpad)]>;
+
 // This instruction is responsible for re-establishing stack pointers after an
 // exception has been caught and we are rejoining normal control flow in the
 // parent function or funclet. It generally sets ESP and EBP, and optionally