9 files changed, 42 insertions, 0 deletions
diff --git a/src/binary-reader-ir.cc b/src/binary-reader-ir.cc
index fb7b53ae..0515f660 100644
--- a/src/binary-reader-ir.cc
+++ b/src/binary-reader-ir.cc
@@ -240,6 +240,7 @@ class BinaryReaderIR : public BinaryReaderNop {
   Result OnInitExprGlobalGetExpr(Index index, Index global_index) override;
   Result OnInitExprI32ConstExpr(Index index, uint32_t value) override;
   Result OnInitExprI64ConstExpr(Index index, uint64_t value) override;
+  Result OnInitExprRefNull(Index index) override;
 
  private:
   Location GetLocation() const;
@@ -1178,6 +1179,12 @@ Result BinaryReaderIR::OnInitExprI64ConstExpr(Index index, uint64_t value) {
   return Result::Ok;
 }
 
+Result BinaryReaderIR::OnInitExprRefNull(Index index) {
+  Location loc = GetLocation();
+  current_init_expr_->push_back(MakeUnique<RefNullExpr>(loc));
+  return Result::Ok;
+}
+
 Result BinaryReaderIR::OnLocalName(Index func_index,
                                    Index local_index,
                                    string_view name) {
diff --git a/src/binary-reader-logging.cc b/src/binary-reader-logging.cc
index ca367855..6d73b89b 100644
--- a/src/binary-reader-logging.cc
+++ b/src/binary-reader-logging.cc
@@ -777,7 +777,9 @@ DEFINE_END(EndNamesSection)
 
 DEFINE_BEGIN(BeginRelocSection)
 DEFINE_END(EndRelocSection)
+
 DEFINE_INDEX_INDEX(OnInitExprGlobalGetExpr, "index", "global_index")
+DEFINE_INDEX(OnInitExprRefNull)
 
 DEFINE_BEGIN(BeginDylinkSection)
 DEFINE_INDEX(OnDylinkNeededCount)
diff --git a/src/binary-reader-logging.h b/src/binary-reader-logging.h
index fab7455d..264f39ac 100644
--- a/src/binary-reader-logging.h
+++ b/src/binary-reader-logging.h
@@ -339,6 +339,7 @@ class BinaryReaderLogging : public BinaryReaderDelegate {
   Result OnInitExprGlobalGetExpr(Index index, Index global_index) override;
   Result OnInitExprI32ConstExpr(Index index, uint32_t value) override;
   Result OnInitExprI64ConstExpr(Index index, uint64_t value) override;
+  Result OnInitExprRefNull(Index index) override;
 
  private:
   void Indent();
diff --git a/src/binary-reader-nop.h b/src/binary-reader-nop.h
index 169eb4f5..8074e419 100644
--- a/src/binary-reader-nop.h
+++ b/src/binary-reader-nop.h
@@ -486,6 +486,9 @@ class BinaryReaderNop : public BinaryReaderDelegate {
   Result OnInitExprI64ConstExpr(Index index, uint64_t value) override {
     return Result::Ok;
   }
+  Result OnInitExprRefNull(Index index) override {
+    return Result::Ok;
+  }
 };
 
 }  // namespace wabt
diff --git a/src/binary-reader-objdump.cc b/src/binary-reader-objdump.cc
index c1feb2fe..371b9a82 100644
--- a/src/binary-reader-objdump.cc
+++ b/src/binary-reader-objdump.cc
@@ -683,6 +683,7 @@ enum class InitExprType {
   F64,
   V128,
   Global,
+  NullRef,
 };
 
 struct InitExpr {
@@ -821,6 +822,7 @@ class BinaryReaderObjdump : public BinaryReaderObjdumpBase {
   Result OnInitExprGlobalGetExpr(Index index, Index global_index) override;
   Result OnInitExprI32ConstExpr(Index index, uint32_t value) override;
   Result OnInitExprI64ConstExpr(Index index, uint64_t value) override;
+  Result OnInitExprRefNull(Index index) override;
 
   Result OnDylinkInfo(uint32_t mem_size,
                       uint32_t mem_align_log2,
@@ -1303,6 +1305,10 @@ void BinaryReaderObjdump::PrintInitExpr(const InitExpr& expr) {
       PrintDetails("\n");
       break;
     }
+    case InitExprType::NullRef: {
+      PrintDetails(" - init nullref\n");
+      break;
+    }
   }
 }
 
@@ -1319,6 +1325,7 @@ static Result InitExprToConstOffset(const InitExpr& expr,
     case InitExprType::F32:
     case InitExprType::F64:
     case InitExprType::V128:
+    case InitExprType::NullRef:
       fprintf(stderr, "Segment/Elem offset must be an i32 init expr");
       return Result::Error;
       break;
@@ -1392,6 +1399,13 @@ Result BinaryReaderObjdump::OnInitExprI64ConstExpr(Index index,
   return Result::Ok;
 }
 
+Result BinaryReaderObjdump::OnInitExprRefNull(Index index) {
+  InitExpr expr;
+  expr.type = InitExprType::NullRef;
+  HandleInitExpr(expr);
+  return Result::Ok;
+}
+
 Result BinaryReaderObjdump::OnModuleName(string_view name) {
   PrintDetails(" - module <" PRIstringview ">\n",
                WABT_PRINTF_STRING_VIEW_ARG(name));
diff --git a/src/binary-reader.cc b/src/binary-reader.cc
index 363edf67..b50c449b 100644
--- a/src/binary-reader.cc
+++ b/src/binary-reader.cc
@@ -480,6 +480,10 @@ Result BinaryReader::ReadInitExpr(Index index, bool require_i32) {
       break;
     }
 
+    case Opcode::RefNull:
+      CALLBACK(OnInitExprRefNull, index);
+      break;
+
     case Opcode::End:
       return Result::Ok;
 
diff --git a/src/binary-reader.h b/src/binary-reader.h
index 87548e82..e89f01b2 100644
--- a/src/binary-reader.h
+++ b/src/binary-reader.h
@@ -410,6 +410,7 @@ class BinaryReaderDelegate {
   virtual Result OnInitExprGlobalGetExpr(Index index, Index global_index) = 0;
   virtual Result OnInitExprI32ConstExpr(Index index, uint32_t value) = 0;
   virtual Result OnInitExprI64ConstExpr(Index index, uint64_t value) = 0;
+  virtual Result OnInitExprRefNull(Index index) = 0;
 
   const State* state = nullptr;
 };
diff --git a/src/interp/binary-reader-interp.cc b/src/interp/binary-reader-interp.cc
index ce45dddf..69539da8 100644
--- a/src/interp/binary-reader-interp.cc
+++ b/src/interp/binary-reader-interp.cc
@@ -245,6 +245,7 @@ class BinaryReaderInterp : public BinaryReaderNop {
                                        Index global_index) override;
   wabt::Result OnInitExprI32ConstExpr(Index index, uint32_t value) override;
   wabt::Result OnInitExprI64ConstExpr(Index index, uint64_t value) override;
+  wabt::Result OnInitExprRefNull(Index index) override;
 
  private:
   Label* GetLabel(Index depth);
@@ -1016,6 +1017,11 @@ wabt::Result BinaryReaderInterp::OnInitExprI64ConstExpr(Index index,
   return wabt::Result::Ok;
 }
 
+wabt::Result BinaryReaderInterp::OnInitExprRefNull(Index index) {
+  PrintError("ref.null global init expressions unimplemented by interpreter");
+  return wabt::Result::Error;
+}
+
 wabt::Result BinaryReaderInterp::OnExport(Index index,
                                           ExternalKind kind,
                                           Index item_index,
diff --git a/src/validator.cc b/src/validator.cc
index 7af62164..e10db823 100644
--- a/src/validator.cc
+++ b/src/validator.cc
@@ -1069,6 +1069,10 @@ void Validator::CheckConstInitExpr(const Location* loc,
         break;
       }
 
+      case ExprType::RefNull:
+        type = Type::Anyref;
+        break;
+      
       default:
         PrintConstExprError(loc, desc);
         return;