[WebAssembly] LSDA info generation

Summary:
This adds support for LSDA (exception table) generation for wasm EH.
Wasm EH mostly follows the structure of Itanium-style exception tables,
with one exception: a call site table entry in wasm EH corresponds to
not a call site but a landing pad.

In wasm EH, the VM is responsible for stack unwinding. After an
exception occurs and the stack is unwound, the control flow is
transferred to wasm 'catch' instruction by the VM, after which the
personality function is called from the compiler-generated code. (Refer
to WasmEHPrepare pass for more information on this part.)

This patch:
- Changes wasm.landingpad.index intrinsic to take a token argument, to
make this 1:1 match with a catchpad instruction
- Stores landingpad index info and catch type info MachineFunction in
before instruction selection
- Lowers wasm.lsda intrinsic to an MCSymbol pointing to the start of an
exception table
- Adds WasmException class with overridden methods for table generation
- Adds support for LSDA section in Wasm object writer

Reviewers: dschuff, sbc100, rnk

Subscribers: mgorny, jgravelle-google, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D52748

llvm-svn: 344575

11 files changed, 234 insertions, 58 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
index 63c5b262edc..526f7ce3083 100644
--- a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -16,6 +16,7 @@
 #include "CodeViewDebug.h"
 #include "DwarfDebug.h"
 #include "DwarfException.h"
+#include "WasmException.h"
 #include "WinCFGuard.h"
 #include "WinException.h"
 #include "llvm/ADT/APFloat.h"
@@ -356,7 +357,7 @@ bool AsmPrinter::doInitialization(Module &M) {
     }
     break;
   case ExceptionHandling::Wasm:
-    // TODO to prevent warning
+    ES = new WasmException(this);
     break;
   }
   if (ES)
diff --git a/llvm/lib/CodeGen/AsmPrinter/CMakeLists.txt b/llvm/lib/CodeGen/AsmPrinter/CMakeLists.txt
index 6cba4a0d4b8..3fb088ab6f0 100644
--- a/llvm/lib/CodeGen/AsmPrinter/CMakeLists.txt
+++ b/llvm/lib/CodeGen/AsmPrinter/CMakeLists.txt
@@ -23,6 +23,7 @@ add_llvm_library(LLVMAsmPrinter
   WinCFGuard.cpp
   WinException.cpp
   CodeViewDebug.cpp
+  WasmException.cpp
 
   DEPENDS
   intrinsics_gen
diff --git a/llvm/lib/CodeGen/AsmPrinter/EHStreamer.cpp b/llvm/lib/CodeGen/AsmPrinter/EHStreamer.cpp
index be04b9a6e8c..7599121de2b 100644
--- a/llvm/lib/CodeGen/AsmPrinter/EHStreamer.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/EHStreamer.cpp
@@ -345,7 +345,9 @@ computeCallSiteTable(SmallVectorImpl<CallSiteEntry> &CallSites,
 ///     unwound and handling continues.
 ///  3. Type ID table contains references to all the C++ typeinfo for all
 ///     catches in the function.  This tables is reverse indexed base 1.
-void EHStreamer::emitExceptionTable() {
+///
+/// Returns the starting symbol of an exception table.
+MCSymbol *EHStreamer::emitExceptionTable() {
   const MachineFunction *MF = Asm->MF;
   const std::vector<const GlobalValue *> &TypeInfos = MF->getTypeInfos();
   const std::vector<unsigned> &FilterIds = MF->getFilterIds();
@@ -375,6 +377,7 @@ void EHStreamer::emitExceptionTable() {
   computeCallSiteTable(CallSites, LandingPads, FirstActions);
 
   bool IsSJLJ = Asm->MAI->getExceptionHandlingType() == ExceptionHandling::SjLj;
+  bool IsWasm = Asm->MAI->getExceptionHandlingType() == ExceptionHandling::Wasm;
   unsigned CallSiteEncoding =
       IsSJLJ ? dwarf::DW_EH_PE_udata4 : dwarf::DW_EH_PE_uleb128;
   bool HaveTTData = !TypeInfos.empty() || !FilterIds.empty();
@@ -457,8 +460,8 @@ void EHStreamer::emitExceptionTable() {
   Asm->EmitLabelDifferenceAsULEB128(CstEndLabel, CstBeginLabel);
   Asm->OutStreamer->EmitLabel(CstBeginLabel);
 
-  // SjLj Exception handling
-  if (IsSJLJ) {
+  // SjLj / Wasm Exception handling
+  if (IsSJLJ || IsWasm) {
     unsigned idx = 0;
     for (SmallVectorImpl<CallSiteEntry>::const_iterator
          I = CallSites.begin(), E = CallSites.end(); I != E; ++I, ++idx) {
@@ -604,6 +607,7 @@ void EHStreamer::emitExceptionTable() {
   }
 
   Asm->EmitAlignment(2);
+  return GCCETSym;
 }
 
 void EHStreamer::emitTypeInfos(unsigned TTypeEncoding, MCSymbol *TTBaseLabel) {
diff --git a/llvm/lib/CodeGen/AsmPrinter/EHStreamer.h b/llvm/lib/CodeGen/AsmPrinter/EHStreamer.h
index b89421a1e06..e3a6f8e9d58 100644
--- a/llvm/lib/CodeGen/AsmPrinter/EHStreamer.h
+++ b/llvm/lib/CodeGen/AsmPrinter/EHStreamer.h
@@ -85,9 +85,10 @@ protected:
   /// zero for the landing pad and the action.  Calls marked 'nounwind' have
   /// no entry and must not be contained in the try-range of any entry - they
   /// form gaps in the table.  Entries must be ordered by try-range address.
-  void computeCallSiteTable(SmallVectorImpl<CallSiteEntry> &CallSites,
-                            const SmallVectorImpl<const LandingPadInfo *> &LandingPads,
-                            const SmallVectorImpl<unsigned> &FirstActions);
+  virtual void computeCallSiteTable(
+      SmallVectorImpl<CallSiteEntry> &CallSites,
+      const SmallVectorImpl<const LandingPadInfo *> &LandingPads,
+      const SmallVectorImpl<unsigned> &FirstActions);
 
   /// Emit landing pads and actions.
   ///
@@ -108,7 +109,9 @@ protected:
   ///     found the frame is unwound and handling continues.
   ///  3. Type id table contains references to all the C++ typeinfo for all
   ///     catches in the function.  This tables is reversed indexed base 1.
-  void emitExceptionTable();
+  ///
+  /// Returns the starting symbol of an exception table.
+  MCSymbol *emitExceptionTable();
 
   virtual void emitTypeInfos(unsigned TTypeEncoding, MCSymbol *TTBaseLabel);
 
diff --git a/llvm/lib/CodeGen/AsmPrinter/WasmException.cpp b/llvm/lib/CodeGen/AsmPrinter/WasmException.cpp
new file mode 100644
index 00000000000..46745d08c9f
--- /dev/null
+++ b/llvm/lib/CodeGen/AsmPrinter/WasmException.cpp
@@ -0,0 +1,81 @@
+//===-- CodeGen/AsmPrinter/WasmException.cpp - Wasm Exception Impl --------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file contains support for writing WebAssembly exception info into asm
+// files.
+//
+//===----------------------------------------------------------------------===//
+
+#include "WasmException.h"
+#include "llvm/MC/MCStreamer.h"
+using namespace llvm;
+
+void WasmException::markFunctionEnd() {
+  // Get rid of any dead landing pads.
+  if (!Asm->MF->getLandingPads().empty()) {
+    auto *NonConstMF = const_cast<MachineFunction *>(Asm->MF);
+    // Wasm does not set BeginLabel and EndLabel information for landing pads,
+    // so we should set the second argument false.
+    NonConstMF->tidyLandingPads(nullptr, /* TidyIfNoBeginLabels */ false);
+  }
+}
+
+void WasmException::endFunction(const MachineFunction *MF) {
+  bool ShouldEmitExceptionTable = false;
+  for (const LandingPadInfo &Info : MF->getLandingPads()) {
+    if (MF->hasWasmLandingPadIndex(Info.LandingPadBlock)) {
+      ShouldEmitExceptionTable = true;
+      break;
+    }
+  }
+  if (!ShouldEmitExceptionTable)
+    return;
+  MCSymbol *LSDALabel = emitExceptionTable();
+  assert(LSDALabel && ".GCC_exception_table has not been emitted!");
+
+  // Wasm requires every data section symbol to have a .size set. So we emit an
+  // end marker and set the size as the difference between the start end the end
+  // marker.
+  MCSymbol *LSDAEndLabel = Asm->createTempSymbol("GCC_except_table_end");
+  Asm->OutStreamer->EmitLabel(LSDAEndLabel);
+  MCContext &OutContext = Asm->OutStreamer->getContext();
+  const MCExpr *SizeExp = MCBinaryExpr::createSub(
+      MCSymbolRefExpr::create(LSDAEndLabel, OutContext),
+      MCSymbolRefExpr::create(LSDALabel, OutContext), OutContext);
+  Asm->OutStreamer->emitELFSize(LSDALabel, SizeExp);
+}
+
+// Compute the call-site table for wasm EH. Even though we use the same function
+// name to share the common routines, a call site entry in the table corresponds
+// to not a call site for possibly-throwing functions but a landing pad. In wasm
+// EH the VM is responsible for stack unwinding. After an exception occurs and
+// the stack is unwound, the control flow is transferred to wasm 'catch'
+// instruction by the VM, after which the personality function is called from
+// the compiler-generated code. Refer to WasmEHPrepare pass for more
+// information.
+void WasmException::computeCallSiteTable(
+    SmallVectorImpl<CallSiteEntry> &CallSites,
+    const SmallVectorImpl<const LandingPadInfo *> &LandingPads,
+    const SmallVectorImpl<unsigned> &FirstActions) {
+  MachineFunction &MF = *Asm->MF;
+  for (unsigned I = 0, N = LandingPads.size(); I < N; ++I) {
+    const LandingPadInfo *Info = LandingPads[I];
+    MachineBasicBlock *LPad = Info->LandingPadBlock;
+    // We don't emit LSDA for single catch (...).
+    if (!MF.hasWasmLandingPadIndex(LPad))
+      continue;
+    // Wasm EH must maintain the EH pads in the order assigned to them by the
+    // WasmEHPrepare pass.
+    unsigned LPadIndex = MF.getWasmLandingPadIndex(LPad);
+    CallSiteEntry Site = {nullptr, nullptr, Info, FirstActions[I]};
+    if (CallSites.size() < LPadIndex + 1)
+      CallSites.resize(LPadIndex + 1);
+    CallSites[LPadIndex] = Site;
+  }
+}
diff --git a/llvm/lib/CodeGen/AsmPrinter/WasmException.h b/llvm/lib/CodeGen/AsmPrinter/WasmException.h
new file mode 100644
index 00000000000..09a9a25ce8d
--- /dev/null
+++ b/llvm/lib/CodeGen/AsmPrinter/WasmException.h
@@ -0,0 +1,42 @@
+//===-- WasmException.h - Wasm Exception Framework -------------*- C++ -*--===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file contains support for writing WebAssembly exception info into asm
+// files.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIB_CODEGEN_ASMPRINTER_WASMEXCEPTION_H
+#define LLVM_LIB_CODEGEN_ASMPRINTER_WASMEXCEPTION_H
+
+#include "EHStreamer.h"
+#include "llvm/CodeGen/AsmPrinter.h"
+
+namespace llvm {
+
+class LLVM_LIBRARY_VISIBILITY WasmException : public EHStreamer {
+public:
+  WasmException(AsmPrinter *A) : EHStreamer(A) {}
+
+  void endModule() override {}
+  void beginFunction(const MachineFunction *MF) override {}
+  virtual void markFunctionEnd() override;
+  void endFunction(const MachineFunction *MF) override;
+
+protected:
+  // Compute the call site table for wasm EH.
+  void computeCallSiteTable(
+      SmallVectorImpl<CallSiteEntry> &CallSites,
+      const SmallVectorImpl<const LandingPadInfo *> &LandingPads,
+      const SmallVectorImpl<unsigned> &FirstActions) override;
+};
+
+} // End of namespace llvm
+
+#endif
diff --git a/llvm/lib/CodeGen/MachineFunction.cpp b/llvm/lib/CodeGen/MachineFunction.cpp
index 431484f078b..9e4963c4bdb 100644
--- a/llvm/lib/CodeGen/MachineFunction.cpp
+++ b/llvm/lib/CodeGen/MachineFunction.cpp
@@ -661,8 +661,11 @@ MCSymbol *MachineFunction::addLandingPad(MachineBasicBlock *LandingPad) {
       }
     }
 
-  } else if (isa<CatchPadInst>(FirstI)) {
-    // TODO
+  } else if (const auto *CPI = dyn_cast<CatchPadInst>(FirstI)) {
+    for (unsigned I = CPI->getNumArgOperands(); I != 0; --I) {
+      Value *TypeInfo = CPI->getArgOperand(I - 1)->stripPointerCasts();
+      addCatchTypeInfo(LandingPad, dyn_cast<GlobalValue>(TypeInfo));
+    }
 
   } else {
     assert(isa<CleanupPadInst>(FirstI) && "Invalid landingpad!");
@@ -687,7 +690,8 @@ void MachineFunction::addFilterTypeInfo(MachineBasicBlock *LandingPad,
   LP.TypeIds.push_back(getFilterIDFor(IdsInFilter));
 }
 
-void MachineFunction::tidyLandingPads(DenseMap<MCSymbol*, uintptr_t> *LPMap) {
+void MachineFunction::tidyLandingPads(DenseMap<MCSymbol *, uintptr_t> *LPMap,
+                                      bool TidyIfNoBeginLabels) {
   for (unsigned i = 0; i != LandingPads.size(); ) {
     LandingPadInfo &LandingPad = LandingPads[i];
     if (LandingPad.LandingPadLabel &&
@@ -702,24 +706,25 @@ void MachineFunction::tidyLandingPads(DenseMap<MCSymbol*, uintptr_t> *LPMap) {
       continue;
     }
 
-    for (unsigned j = 0, e = LandingPads[i].BeginLabels.size(); j != e; ++j) {
-      MCSymbol *BeginLabel = LandingPad.BeginLabels[j];
-      MCSymbol *EndLabel = LandingPad.EndLabels[j];
-      if ((BeginLabel->isDefined() ||
-           (LPMap && (*LPMap)[BeginLabel] != 0)) &&
-          (EndLabel->isDefined() ||
-           (LPMap && (*LPMap)[EndLabel] != 0))) continue;
-
-      LandingPad.BeginLabels.erase(LandingPad.BeginLabels.begin() + j);
-      LandingPad.EndLabels.erase(LandingPad.EndLabels.begin() + j);
-      --j;
-      --e;
-    }
+    if (TidyIfNoBeginLabels) {
+      for (unsigned j = 0, e = LandingPads[i].BeginLabels.size(); j != e; ++j) {
+        MCSymbol *BeginLabel = LandingPad.BeginLabels[j];
+        MCSymbol *EndLabel = LandingPad.EndLabels[j];
+        if ((BeginLabel->isDefined() || (LPMap && (*LPMap)[BeginLabel] != 0)) &&
+            (EndLabel->isDefined() || (LPMap && (*LPMap)[EndLabel] != 0)))
+          continue;
+
+        LandingPad.BeginLabels.erase(LandingPad.BeginLabels.begin() + j);
+        LandingPad.EndLabels.erase(LandingPad.EndLabels.begin() + j);
+        --j;
+        --e;
+      }
 
-    // Remove landing pads with no try-ranges.
-    if (LandingPads[i].BeginLabels.empty()) {
-      LandingPads.erase(LandingPads.begin() + i);
-      continue;
+      // Remove landing pads with no try-ranges.
+      if (LandingPads[i].BeginLabels.empty()) {
+        LandingPads.erase(LandingPads.begin() + i);
+        continue;
+      }
     }
 
     // If there is no landing pad, ensure that the list of typeids is empty.
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index 1a99ef734f1..3907f647142 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -6282,12 +6282,12 @@ SelectionDAGBuilder::visitIntrinsicCall(const CallInst &I, unsigned Intrinsic) {
     return nullptr;
   }
 
-  case Intrinsic::wasm_landingpad_index: {
-    // TODO store landing pad index in a map, which will be used when generating
-    // LSDA information
+  case Intrinsic::wasm_landingpad_index:
+    // Information this intrinsic contained has been transferred to
+    // MachineFunction in SelectionDAGISel::PrepareEHLandingPad. We can safely
+    // delete it now.
     return nullptr;
   }
-  }
 }
 
 void SelectionDAGBuilder::visitConstrainedFPIntrinsic(
@@ -6444,7 +6444,7 @@ SelectionDAGBuilder::lowerInvokable(TargetLowering::CallLoweringInfo &CLI,
       WinEHFuncInfo *EHInfo = DAG.getMachineFunction().getWinEHFuncInfo();
       EHInfo->addIPToStateRange(cast<InvokeInst>(CLI.CS.getInstruction()),
                                 BeginLabel, EndLabel);
-    } else {
+    } else if (!isScopedEHPersonality(Pers)) {
       MF.addInvoke(FuncInfo.MBBMap[EHPadBB], BeginLabel, EndLabel);
     }
   }
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
index 2b4a590f19f..90bcaa653c3 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
@@ -27,6 +27,7 @@
 #include "llvm/Analysis/AliasAnalysis.h"
 #include "llvm/Analysis/BranchProbabilityInfo.h"
 #include "llvm/Analysis/CFG.h"
+#include "llvm/Analysis/EHPersonalities.h"
 #include "llvm/Analysis/OptimizationRemarkEmitter.h"
 #include "llvm/Analysis/TargetLibraryInfo.h"
 #include "llvm/Analysis/TargetTransformInfo.h"
@@ -1128,6 +1129,36 @@ static bool hasExceptionPointerOrCodeUser(const CatchPadInst *CPI) {
   return false;
 }
 
+// wasm.landingpad.index intrinsic is for associating a landing pad index number
+// with a catchpad instruction. Retrieve the landing pad index in the intrinsic
+// and store the mapping in the function.
+static void mapWasmLandingPadIndex(MachineBasicBlock *MBB,
+                                   const CatchPadInst *CPI) {
+  MachineFunction *MF = MBB->getParent();
+  // In case of single catch (...), we don't emit LSDA, so we don't need
+  // this information.
+  bool IsSingleCatchAllClause =
+      CPI->getNumArgOperands() == 1 &&
+      cast<Constant>(CPI->getArgOperand(0))->isNullValue();
+  if (!IsSingleCatchAllClause) {
+    // Create a mapping from landing pad label to landing pad index.
+    bool IntrFound = false;
+    for (const User *U : CPI->users()) {
+      if (const auto *Call = dyn_cast<IntrinsicInst>(U)) {
+        Intrinsic::ID IID = Call->getIntrinsicID();
+        if (IID == Intrinsic::wasm_landingpad_index) {
+          Value *IndexArg = Call->getArgOperand(1);
+          int Index = cast<ConstantInt>(IndexArg)->getZExtValue();
+          MF->setWasmLandingPadIndex(MBB, Index);
+          IntrFound = true;
+          break;
+        }
+      }
+    }
+    assert(IntrFound && "wasm.landingpad.index intrinsic not found!");
+  }
+}
+
 /// PrepareEHLandingPad - Emit an EH_LABEL, set up live-in registers, and
 /// do other setup for EH landing-pad blocks.
 bool SelectionDAGISel::PrepareEHLandingPad() {
@@ -1137,44 +1168,48 @@ bool SelectionDAGISel::PrepareEHLandingPad() {
   const TargetRegisterClass *PtrRC =
       TLI->getRegClassFor(TLI->getPointerTy(CurDAG->getDataLayout()));
 
+  auto Pers = classifyEHPersonality(PersonalityFn);
+
   // Catchpads have one live-in register, which typically holds the exception
   // pointer or code.
-  if (const auto *CPI = dyn_cast<CatchPadInst>(LLVMBB->getFirstNonPHI())) {
-    if (hasExceptionPointerOrCodeUser(CPI)) {
-      // Get or create the virtual register to hold the pointer or code.  Mark
-      // the live in physreg and copy into the vreg.
-      MCPhysReg EHPhysReg = TLI->getExceptionPointerRegister(PersonalityFn);
-      assert(EHPhysReg && "target lacks exception pointer register");
-      MBB->addLiveIn(EHPhysReg);
-      unsigned VReg = FuncInfo->getCatchPadExceptionPointerVReg(CPI, PtrRC);
-      BuildMI(*MBB, FuncInfo->InsertPt, SDB->getCurDebugLoc(),
-              TII->get(TargetOpcode::COPY), VReg)
-          .addReg(EHPhysReg, RegState::Kill);
+  if (isFuncletEHPersonality(Pers)) {
+    if (const auto *CPI = dyn_cast<CatchPadInst>(LLVMBB->getFirstNonPHI())) {
+      if (hasExceptionPointerOrCodeUser(CPI)) {
+        // Get or create the virtual register to hold the pointer or code.  Mark
+        // the live in physreg and copy into the vreg.
+        MCPhysReg EHPhysReg = TLI->getExceptionPointerRegister(PersonalityFn);
+        assert(EHPhysReg && "target lacks exception pointer register");
+        MBB->addLiveIn(EHPhysReg);
+        unsigned VReg = FuncInfo->getCatchPadExceptionPointerVReg(CPI, PtrRC);
+        BuildMI(*MBB, FuncInfo->InsertPt, SDB->getCurDebugLoc(),
+                TII->get(TargetOpcode::COPY), VReg)
+            .addReg(EHPhysReg, RegState::Kill);
+      }
     }
     return true;
   }
 
-  if (!LLVMBB->isLandingPad())
-    return true;
-
   // Add a label to mark the beginning of the landing pad.  Deletion of the
   // landing pad can thus be detected via the MachineModuleInfo.
   MCSymbol *Label = MF->addLandingPad(MBB);
 
-  // Assign the call site to the landing pad's begin label.
-  MF->setCallSiteLandingPad(Label, SDB->LPadToCallSiteMap[MBB]);
-
   const MCInstrDesc &II = TII->get(TargetOpcode::EH_LABEL);
   BuildMI(*MBB, FuncInfo->InsertPt, SDB->getCurDebugLoc(), II)
     .addSym(Label);
 
-  // Mark exception register as live in.
-  if (unsigned Reg = TLI->getExceptionPointerRegister(PersonalityFn))
-    FuncInfo->ExceptionPointerVirtReg = MBB->addLiveIn(Reg, PtrRC);
-
-  // Mark exception selector register as live in.
-  if (unsigned Reg = TLI->getExceptionSelectorRegister(PersonalityFn))
-    FuncInfo->ExceptionSelectorVirtReg = MBB->addLiveIn(Reg, PtrRC);
+  if (Pers == EHPersonality::Wasm_CXX) {
+    if (const auto *CPI = dyn_cast<CatchPadInst>(LLVMBB->getFirstNonPHI()))
+      mapWasmLandingPadIndex(MBB, CPI);
+  } else {
+    // Assign the call site to the landing pad's begin label.
+    MF->setCallSiteLandingPad(Label, SDB->LPadToCallSiteMap[MBB]);
+    // Mark exception register as live in.
+    if (unsigned Reg = TLI->getExceptionPointerRegister(PersonalityFn))
+      FuncInfo->ExceptionPointerVirtReg = MBB->addLiveIn(Reg, PtrRC);
+    // Mark exception selector register as live in.
+    if (unsigned Reg = TLI->getExceptionSelectorRegister(PersonalityFn))
+      FuncInfo->ExceptionSelectorVirtReg = MBB->addLiveIn(Reg, PtrRC);
+  }
 
   return true;
 }
diff --git a/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
index b046cd81d6c..341ab927861 100644
--- a/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
+++ b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
@@ -1748,6 +1748,10 @@ const MCExpr *TargetLoweringObjectFileWasm::lowerRelativeReference(
 void TargetLoweringObjectFileWasm::InitializeWasm() {
   StaticCtorSection =
       getContext().getWasmSection(".init_array", SectionKind::getData());
+
+  // We don't use PersonalityEncoding and LSDAEncoding because we don't emit
+  // .cfi directives. We use TTypeEncoding to encode typeinfo global variables.
+  TTypeEncoding = dwarf::DW_EH_PE_absptr;
 }
 
 MCSection *TargetLoweringObjectFileWasm::getStaticCtorSection(
diff --git a/llvm/lib/CodeGen/WasmEHPrepare.cpp b/llvm/lib/CodeGen/WasmEHPrepare.cpp
index 83d04da5dd0..6f02a05f561 100644
--- a/llvm/lib/CodeGen/WasmEHPrepare.cpp
+++ b/llvm/lib/CodeGen/WasmEHPrepare.cpp
@@ -300,7 +300,7 @@ void WasmEHPrepare::prepareEHPad(BasicBlock *BB, unsigned Index) {
   // This is to create a map of <landingpad EH label, landingpad index> in
   // SelectionDAGISel, which is to be used in EHStreamer to emit LSDA tables.
   // Pseudocode: wasm.landingpad.index(Index);
-  IRB.CreateCall(LPadIndexF, IRB.getInt32(Index));
+  IRB.CreateCall(LPadIndexF, {FPI, IRB.getInt32(Index)});
 
   // Pseudocode: __wasm_lpad_context.lpad_index = index;
   IRB.CreateStore(IRB.getInt32(Index), LPadIndexField);