[EH] Remove `unwind` (#1682)

`unwind` was removed. See WebAssembly/exception-handling#156.

32 files changed, 14 insertions, 325 deletions

diff --git a/src/binary-reader-ir.cc b/src/binary-reader-ir.cc
index 1251c0af..19fec5c9 100644
--- a/src/binary-reader-ir.cc
+++ b/src/binary-reader-ir.cc
@@ -199,7 +199,6 @@ class BinaryReaderIR : public BinaryReaderNop {
   Result OnUnaryExpr(Opcode opcode) override;
   Result OnTernaryExpr(Opcode opcode) override;
   Result OnUnreachableExpr() override;
-  Result OnUnwindExpr() override;
   Result EndFunctionBody(Index index) override;
   Result OnSimdLaneOpExpr(Opcode opcode, uint64_t value) override;
   Result OnSimdLoadLaneExpr(Opcode opcode,
@@ -813,7 +812,6 @@ Result BinaryReaderIR::OnEndExpr() {
 
     case LabelType::Func:
     case LabelType::Catch:
-    case LabelType::Unwind:
       break;
   }
 
@@ -1015,7 +1013,7 @@ Result BinaryReaderIR::AppendCatch(Catch&& catch_) {
   if (try_->kind == TryKind::Invalid) {
     try_->kind = TryKind::Catch;
   } else if (try_->kind != TryKind::Catch) {
-    PrintError("catch not allowed in try-unwind or try-delegate");
+    PrintError("catch not allowed in try-delegate");
     return Result::Error;
   }
 
@@ -1032,28 +1030,6 @@ Result BinaryReaderIR::OnCatchAllExpr() {
   return AppendCatch(Catch(GetLocation()));
 }
 
-Result BinaryReaderIR::OnUnwindExpr() {
-  LabelNode* label = nullptr;
-  CHECK_RESULT(TopLabel(&label));
-
-  if (label->label_type != LabelType::Try) {
-    PrintError("unwind not inside try block");
-    return Result::Error;
-  }
-
-  auto* try_ = cast<TryExpr>(label->context);
-
-  if (try_->kind == TryKind::Invalid) {
-    try_->kind = TryKind::Unwind;
-  } else if (try_->kind != TryKind::Unwind) {
-    PrintError("unwind not allowed in try-catch or try-delegate");
-    return Result::Error;
-  }
-
-  label->exprs = &try_->unwind;
-  return Result::Ok;
-}
-
 Result BinaryReaderIR::OnDelegateExpr(Index depth) {
   LabelNode* label = nullptr;
   CHECK_RESULT(TopLabel(&label));
@@ -1068,7 +1044,7 @@ Result BinaryReaderIR::OnDelegateExpr(Index depth) {
   if (try_->kind == TryKind::Invalid) {
     try_->kind = TryKind::Delegate;
   } else if (try_->kind != TryKind::Delegate) {
-    PrintError("delegate not allowed in try-catch or try-unwind");
+    PrintError("delegate not allowed in try-catch");
     return Result::Error;
   }
 
diff --git a/src/binary-reader-logging.cc b/src/binary-reader-logging.cc
index 71e43864..d67bb5cb 100644
--- a/src/binary-reader-logging.cc
+++ b/src/binary-reader-logging.cc
@@ -844,7 +844,6 @@ DEFINE_LOAD_STORE_OPCODE(OnLoadZeroExpr);
 DEFINE_LOAD_STORE_OPCODE(OnStoreExpr);
 DEFINE_INDEX_DESC(OnThrowExpr, "tag_index")
 DEFINE0(OnUnreachableExpr)
-DEFINE0(OnUnwindExpr)
 DEFINE_OPCODE(OnUnaryExpr)
 DEFINE_OPCODE(OnTernaryExpr)
 DEFINE_SIMD_LOAD_STORE_LANE_OPCODE(OnSimdLoadLaneExpr);
diff --git a/src/binary-reader-logging.h b/src/binary-reader-logging.h
index 9b7eb862..5e385748 100644
--- a/src/binary-reader-logging.h
+++ b/src/binary-reader-logging.h
@@ -222,7 +222,6 @@ class BinaryReaderLogging : public BinaryReaderDelegate {
   Result OnUnaryExpr(Opcode opcode) override;
   Result OnTernaryExpr(Opcode opcode) override;
   Result OnUnreachableExpr() override;
-  Result OnUnwindExpr() override;
   Result OnAtomicWaitExpr(Opcode opcode,
                           Address alignment_log2,
                           Address offset) override;
diff --git a/src/binary-reader-nop.h b/src/binary-reader-nop.h
index c069914f..1ae01e53 100644
--- a/src/binary-reader-nop.h
+++ b/src/binary-reader-nop.h
@@ -303,7 +303,6 @@ class BinaryReaderNop : public BinaryReaderDelegate {
   Result OnUnaryExpr(Opcode opcode) override { return Result::Ok; }
   Result OnTernaryExpr(Opcode opcode) override { return Result::Ok; }
   Result OnUnreachableExpr() override { return Result::Ok; }
-  Result OnUnwindExpr() override { return Result::Ok; }
   Result EndFunctionBody(Index index) override { return Result::Ok; }
   Result EndCodeSection() override { return Result::Ok; }
   Result OnSimdLaneOpExpr(Opcode opcode, uint64_t value) override {
diff --git a/src/binary-reader-objdump.cc b/src/binary-reader-objdump.cc
index 20f82c86..1f02d335 100644
--- a/src/binary-reader-objdump.cc
+++ b/src/binary-reader-objdump.cc
@@ -598,7 +598,6 @@ void BinaryReaderObjdumpDisassemble::LogOpcode(size_t data_size,
         case Opcode::Else:
         case Opcode::Catch:
         case Opcode::CatchAll:
-        case Opcode::Unwind:
           indent_level--;
         default:
           break;
diff --git a/src/binary-reader.cc b/src/binary-reader.cc
index 6892bbcc..42fb5029 100644
--- a/src/binary-reader.cc
+++ b/src/binary-reader.cc
@@ -1435,12 +1435,6 @@ Result BinaryReader::ReadFunctionBody(Offset end_offset) {
         break;
       }
 
-      case Opcode::Unwind: {
-        CALLBACK0(OnUnwindExpr);
-        CALLBACK0(OnOpcodeBare);
-        break;
-      }
-
       case Opcode::Delegate: {
         Index index;
         CHECK_RESULT(ReadIndex(&index, "depth"));
diff --git a/src/binary-reader.h b/src/binary-reader.h
index a9463ce5..a688eada 100644
--- a/src/binary-reader.h
+++ b/src/binary-reader.h
@@ -290,7 +290,6 @@ class BinaryReaderDelegate {
   virtual Result OnUnaryExpr(Opcode opcode) = 0;
   virtual Result OnTernaryExpr(Opcode opcode) = 0;
   virtual Result OnUnreachableExpr() = 0;
-  virtual Result OnUnwindExpr() = 0;
   virtual Result EndFunctionBody(Index index) = 0;
   virtual Result EndCodeSection() = 0;
 
diff --git a/src/binary-writer.cc b/src/binary-writer.cc
index 2cac2967..5638bd4e 100644
--- a/src/binary-writer.cc
+++ b/src/binary-writer.cc
@@ -1006,11 +1006,6 @@ void BinaryWriter::WriteExpr(const Func* func, const Expr* expr) {
           }
           WriteOpcode(stream_, Opcode::End);
           break;
-        case TryKind::Unwind:
-          WriteOpcode(stream_, Opcode::Unwind);
-          WriteExprList(func, try_expr->unwind);
-          WriteOpcode(stream_, Opcode::End);
-          break;
         case TryKind::Delegate:
           WriteOpcode(stream_, Opcode::Delegate);
           WriteU32Leb128(stream_,
diff --git a/src/common.h b/src/common.h
index c48f22de..d90ba45b 100644
--- a/src/common.h
+++ b/src/common.h
@@ -230,10 +230,9 @@ enum class LabelType {
   Else,
   Try,
   Catch,
-  Unwind,
 
   First = Func,
-  Last = Unwind,
+  Last = Catch,
 };
 static const int kLabelTypeCount = WABT_ENUM_COUNT(LabelType);
 
diff --git a/src/expr-visitor.cc b/src/expr-visitor.cc
index 5ef2b473..fa572285 100644
--- a/src/expr-visitor.cc
+++ b/src/expr-visitor.cc
@@ -107,10 +107,6 @@ Result ExprVisitor::VisitExpr(Expr* root_expr) {
                 CHECK_RESULT(delegate_->EndTryExpr(try_expr));
               }
               break;
-            case TryKind::Unwind:
-              CHECK_RESULT(delegate_->OnUnwindExpr(try_expr));
-              PushExprlist(State::Unwind, expr, try_expr->unwind);
-              break;
             case TryKind::Delegate:
               CHECK_RESULT(delegate_->OnDelegateExpr(try_expr));
               break;
@@ -141,18 +137,6 @@ Result ExprVisitor::VisitExpr(Expr* root_expr) {
         }
         break;
       }
-
-      case State::Unwind: {
-        auto try_expr = cast<TryExpr>(expr);
-        auto& iter = expr_iter_stack_.back();
-        if (iter != try_expr->unwind.end()) {
-          PushDefault(&*iter++);
-        } else {
-          CHECK_RESULT(delegate_->EndTryExpr(try_expr));
-          PopExprlist();
-        }
-        break;
-      }
     }
   }
 
diff --git a/src/expr-visitor.h b/src/expr-visitor.h
index 19277d56..eda287f0 100644
--- a/src/expr-visitor.h
+++ b/src/expr-visitor.h
@@ -42,7 +42,6 @@ class ExprVisitor {
     Loop,
     Try,
     Catch,
-    Unwind,
   };
 
   Result HandleDefaultState(Expr*);
@@ -118,7 +117,6 @@ class ExprVisitor::Delegate {
   virtual Result OnUnreachableExpr(UnreachableExpr*) = 0;
   virtual Result BeginTryExpr(TryExpr*) = 0;
   virtual Result OnCatchExpr(TryExpr*, Catch*) = 0;
-  virtual Result OnUnwindExpr(TryExpr*) = 0;
   virtual Result OnDelegateExpr(TryExpr*) = 0;
   virtual Result EndTryExpr(TryExpr*) = 0;
   virtual Result OnThrowExpr(ThrowExpr*) = 0;
@@ -193,7 +191,6 @@ class ExprVisitor::DelegateNop : public ExprVisitor::Delegate {
   Result OnUnreachableExpr(UnreachableExpr*) override { return Result::Ok; }
   Result BeginTryExpr(TryExpr*) override { return Result::Ok; }
   Result OnCatchExpr(TryExpr*, Catch*) override { return Result::Ok; }
-  Result OnUnwindExpr(TryExpr*) override { return Result::Ok; }
   Result OnDelegateExpr(TryExpr*) override { return Result::Ok; }
   Result EndTryExpr(TryExpr*) override { return Result::Ok; }
   Result OnThrowExpr(ThrowExpr*) override { return Result::Ok; }
diff --git a/src/interp/interp.cc b/src/interp/interp.cc
index 6a7fd2fe..44fa5b66 100644
--- a/src/interp/interp.cc
+++ b/src/interp/interp.cc
@@ -1794,7 +1794,6 @@ RunResult Thread::StepInternal(Trap::Ptr* out_trap) {
     case O::Try:
     case O::Catch:
     case O::CatchAll:
-    case O::Unwind:
     case O::Delegate:
     case O::Throw:
     case O::Rethrow:
diff --git a/src/interp/istream.cc b/src/interp/istream.cc
index cc8ec547..609c6923 100644
--- a/src/interp/istream.cc
+++ b/src/interp/istream.cc
@@ -764,7 +764,6 @@ Instr Istream::Read(Offset* offset) const {
     case Opcode::Rethrow:
     case Opcode::Throw:
     case Opcode::Try:
-    case Opcode::Unwind:
     case Opcode::ReturnCall:
       // Not used.
       break;
diff --git a/src/ir.h b/src/ir.h
index ca2d6c2f..d68cd141 100644
--- a/src/ir.h
+++ b/src/ir.h
@@ -380,7 +380,6 @@ typedef std::vector<Catch> CatchVector;
 enum class TryKind {
   Invalid,
   Catch,
-  Unwind,
   Delegate
 };
 
@@ -609,7 +608,6 @@ class TryExpr : public ExprMixin<ExprType::Try> {
   TryKind kind;
   Block block;
   CatchVector catches;
-  ExprList unwind;
   Var delegate_target;
 };
 
diff --git a/src/lexer-keywords.txt b/src/lexer-keywords.txt
index 67eb7fad..9f23590e 100644
--- a/src/lexer-keywords.txt
+++ b/src/lexer-keywords.txt
@@ -628,4 +628,3 @@ i64.trunc_u:sat/f64, TokenType::Convert, Opcode::I64TruncSatF64U
 set_global, TokenType::GlobalSet, Opcode::GlobalSet
 set_local, TokenType::LocalSet, Opcode::LocalSet
 tee_local, TokenType::LocalTee, Opcode::LocalTee
-unwind, TokenType::Unwind, Opcode::Unwind
diff --git a/src/opcode.cc b/src/opcode.cc
index 1883aa86..d4ffcdc1 100644
--- a/src/opcode.cc
+++ b/src/opcode.cc
@@ -65,7 +65,6 @@ bool Opcode::IsEnabled(const Features& features) const {
   switch (enum_) {
     case Opcode::Try:
     case Opcode::Catch:
-    case Opcode::Unwind:
     case Opcode::Delegate:
     case Opcode::Throw:
     case Opcode::Rethrow:
diff --git a/src/opcode.def b/src/opcode.def
index 18c415ca..846841d1 100644
--- a/src/opcode.def
+++ b/src/opcode.def
@@ -45,7 +45,6 @@ WABT_OPCODE(___,  ___,  ___,  ___,  0,  0,    0x06, Try, "try", "")
 WABT_OPCODE(___,  ___,  ___,  ___,  0,  0,    0x07, Catch, "catch", "")
 WABT_OPCODE(___,  ___,  ___,  ___,  0,  0,    0x08, Throw, "throw", "")
 WABT_OPCODE(___,  ___,  ___,  ___,  0,  0,    0x09, Rethrow, "rethrow", "")
-WABT_OPCODE(___,  ___,  ___,  ___,  0,  0,    0x0a, Unwind, "unwind", "")
 WABT_OPCODE(___,  ___,  ___,  ___,  0,  0,    0x0b, End, "end", "")
 WABT_OPCODE(___,  ___,  ___,  ___,  0,  0,    0x0c, Br, "br", "")
 WABT_OPCODE(___,  I32,  ___,  ___,  0,  0,    0x0d, BrIf, "br_if", "")
diff --git a/src/prebuilt/lexer-keywords.cc b/src/prebuilt/lexer-keywords.cc
index 3e74f582..0c2d8df8 100644
--- a/src/prebuilt/lexer-keywords.cc
+++ b/src/prebuilt/lexer-keywords.cc
@@ -158,7 +158,7 @@ Perfect_Hash::InWordSet (const char *str, size_t len)
 {
   enum
     {
-      TOTAL_KEYWORDS = 611,
+      TOTAL_KEYWORDS = 610,
       MIN_WORD_LENGTH = 2,
       MAX_WORD_LENGTH = 29,
       MIN_HASH_VALUE = 19,
@@ -457,8 +457,7 @@ Perfect_Hash::InWordSet (const char *str, size_t len)
       {"i64x2.bitmask", TokenType::Unary, Opcode::I64X2Bitmask},
 #line 383 "src/lexer-keywords.txt"
       {"i64.atomic.store32", TokenType::AtomicStore, Opcode::I64AtomicStore32},
-#line 631 "src/lexer-keywords.txt"
-      {"unwind", TokenType::Unwind, Opcode::Unwind},
+      {""},
 #line 407 "src/lexer-keywords.txt"
       {"i64.load32_u", TokenType::Load, Opcode::I64Load32U},
       {""},
diff --git a/src/shared-validator.cc b/src/shared-validator.cc
index 0071d2f2..214c4204 100644
--- a/src/shared-validator.cc
+++ b/src/shared-validator.cc
@@ -1241,11 +1241,4 @@ Result SharedValidator::OnUnreachable(const Location& loc) {
   return result;
 }
 
-Result SharedValidator::OnUnwind(const Location& loc) {
-  Result result = Result::Ok;
-  expr_loc_ = &loc;
-  result |= typechecker_.OnUnwind();
-  return result;
-}
-
 }  // namespace wabt
diff --git a/src/shared-validator.h b/src/shared-validator.h
index f5b8ce9a..da49e4e0 100644
--- a/src/shared-validator.h
+++ b/src/shared-validator.h
@@ -175,7 +175,6 @@ class SharedValidator {
   Result OnTry(const Location&, Type sig_type);
   Result OnUnary(const Location&, Opcode);
   Result OnUnreachable(const Location&);
-  Result OnUnwind(const Location&);
 
  private:
   struct FuncType {
diff --git a/src/token.def b/src/token.def
index a54e37ac..4c582491 100644
--- a/src/token.def
+++ b/src/token.def
@@ -145,9 +145,8 @@ WABT_TOKEN(Throw, "throw")
 WABT_TOKEN(Try, "try")
 WABT_TOKEN(Unary, "UNARY")
 WABT_TOKEN(Unreachable, "unreachable")
-WABT_TOKEN(Unwind, "unwind")
 WABT_TOKEN_FIRST(Opcode, AtomicFence)
-WABT_TOKEN_LAST(Opcode, Unwind)
+WABT_TOKEN_LAST(Opcode, Unreachable)
 
 /* Tokens with string data. */
 WABT_TOKEN(AlignEqNat, "align=")
diff --git a/src/type-checker.cc b/src/type-checker.cc
index 1826e1d2..1daa5ecf 100644
--- a/src/type-checker.cc
+++ b/src/type-checker.cc
@@ -589,11 +589,10 @@ Result TypeChecker::OnElse() {
 }
 
 Result TypeChecker::OnEnd(Label* label,
-                          TypeVector& check_type,
                           const char* sig_desc,
                           const char* end_desc) {
   Result result = Result::Ok;
-  result |= PopAndCheckSignature(check_type, sig_desc);
+  result |= PopAndCheckSignature(label->result_types, sig_desc);
   result |= CheckTypeStackEnd(end_desc);
   ResetTypeStackToLabel(label);
   PushTypes(label->result_types);
@@ -604,8 +603,7 @@ Result TypeChecker::OnEnd(Label* label,
 Result TypeChecker::OnEnd() {
   Result result = Result::Ok;
   static const char* s_label_type_name[] = {
-      "function", "block", "loop", "if", "if false branch", "try",
-      "try catch", "try unwind"};
+      "function", "block", "loop", "if", "if false branch", "try", "try catch"};
   WABT_STATIC_ASSERT(WABT_ARRAY_SIZE(s_label_type_name) == kLabelTypeCount);
   Label* label;
   CHECK_RESULT(TopLabel(&label));
@@ -618,15 +616,7 @@ Result TypeChecker::OnEnd() {
   }
 
   const char* desc = s_label_type_name[static_cast<int>(label->label_type)];
-  if (label->label_type == LabelType::Unwind) {
-    // Unwind is unusual in that it always unwinds the control stack at the end,
-    // and therefore the return type of the unwind expressions are not the same
-    // as the block return type.
-    TypeVector empty;
-    result |= OnEnd(label, empty, desc, desc);
-  } else {
-    result |= OnEnd(label, label->result_types, desc, desc);
-  }
+  result |= OnEnd(label, desc, desc);
   return result;
 }
 
@@ -914,25 +904,12 @@ Result TypeChecker::OnUnreachable() {
   return SetUnreachable();
 }
 
-Result TypeChecker::OnUnwind() {
-  Result result = Result::Ok;
-  Label* label;
-  CHECK_RESULT(TopLabel(&label));
-  result |= CheckLabelType(label, LabelType::Try);
-  result |= PopAndCheckSignature(label->result_types, "try block");
-  result |= CheckTypeStackEnd("try block");
-  ResetTypeStackToLabel(label);
-  label->label_type = LabelType::Unwind;
-  label->unreachable = false;
-  return result;
-}
-
 Result TypeChecker::EndFunction() {
   Result result = Result::Ok;
   Label* label;
   CHECK_RESULT(TopLabel(&label));
   result |= CheckLabelType(label, LabelType::Func);
-  result |= OnEnd(label, label->result_types, "implicit return", "function");
+  result |= OnEnd(label, "implicit return", "function");
   return result;
 }
 
diff --git a/src/type-checker.h b/src/type-checker.h
index b183ee07..4a027568 100644
--- a/src/type-checker.h
+++ b/src/type-checker.h
@@ -125,7 +125,6 @@ class TypeChecker {
   Result OnTry(const TypeVector& param_types, const TypeVector& result_types);
   Result OnUnary(Opcode);
   Result OnUnreachable();
-  Result OnUnwind();
   Result EndFunction();
 
   static Result CheckType(Type actual, Type expected);
@@ -169,7 +168,7 @@ class TypeChecker {
                       const Limits* limits1 = nullptr,
                       const Limits* limits2 = nullptr,
                       const Limits* limits3 = nullptr);
-  Result OnEnd(Label* label, TypeVector& check_type, const char* sig_desc, const char* end_desc);
+  Result OnEnd(Label* label, const char* sig_desc, const char* end_desc);
 
   template <typename... Args>
   void PrintStackIfFailed(Result result, const char* desc, Args... args) {
diff --git a/src/validator.cc b/src/validator.cc
index e192ff98..b98121d4 100644
--- a/src/validator.cc
+++ b/src/validator.cc
@@ -135,7 +135,6 @@ class Validator : public ExprVisitor::Delegate {
   Result OnUnreachableExpr(UnreachableExpr*) override;
   Result BeginTryExpr(TryExpr*) override;
   Result OnCatchExpr(TryExpr*, Catch*) override;
-  Result OnUnwindExpr(TryExpr*) override;
   Result OnDelegateExpr(TryExpr*) override;
   Result EndTryExpr(TryExpr*) override;
   Result OnThrowExpr(ThrowExpr*) override;
@@ -499,11 +498,6 @@ Result Validator::OnCatchExpr(TryExpr*, Catch* catch_) {
   return Result::Ok;
 }
 
-Result Validator::OnUnwindExpr(TryExpr* expr) {
-  result_ |= validator_.OnUnwind(expr->loc);
-  return Result::Ok;
-}
-
 Result Validator::OnDelegateExpr(TryExpr* expr) {
   result_ |= validator_.OnDelegate(expr->loc, expr->delegate_target);
   return Result::Ok;
diff --git a/src/wast-parser.cc b/src/wast-parser.cc
index 955b6a3d..22dd5322 100644
--- a/src/wast-parser.cc
+++ b/src/wast-parser.cc
@@ -2591,10 +2591,6 @@ Result WastParser::ParseBlockInstr(std::unique_ptr<Expr>* out_expr) {
       if (IsCatch(Peek())) {
         CHECK_RESULT(ParseCatchInstrList(&expr->catches));
         expr->kind = TryKind::Catch;
-      } else if (PeekMatch(TokenType::Unwind)) {
-        Consume();
-        CHECK_RESULT(ParseInstrList(&expr->unwind));
-        expr->kind = TryKind::Unwind;
       } else if (PeekMatch(TokenType::Delegate)) {
         Consume();
         Var var;
@@ -2602,7 +2598,7 @@ Result WastParser::ParseBlockInstr(std::unique_ptr<Expr>* out_expr) {
         expr->delegate_target = var;
         expr->kind = TryKind::Delegate;
       } else {
-        return ErrorExpected({"catch", "catch_all", "unwind", "delegate"});
+        return ErrorExpected({"catch", "catch_all", "delegate"});
       }
       CHECK_RESULT(ErrorIfLpar({"a valid try clause"}));
       expr->block.end_loc = GetLocation();
@@ -2779,12 +2775,6 @@ Result WastParser::ParseExpr(ExprList* exprs) {
             CHECK_RESULT(ParseCatchExprList(&expr->catches));
             expr->kind = TryKind::Catch;
             break;
-          case TokenType::Unwind:
-            Consume();
-            CHECK_RESULT(ParseTerminatingInstrList(&expr->unwind));
-            expr->kind = TryKind::Unwind;
-            EXPECT(Rpar);
-            break;
           case TokenType::Delegate: {
             Consume();
             Var var;
@@ -2795,7 +2785,7 @@ Result WastParser::ParseExpr(ExprList* exprs) {
             break;
           }
           default:
-            ErrorExpected({"catch", "catch_all", "unwind", "delegate"});
+            ErrorExpected({"catch", "catch_all", "delegate"});
             break;
         }
         CHECK_RESULT(ErrorIfLpar({"a valid try clause"}));
diff --git a/src/wat-writer.cc b/src/wat-writer.cc
index e3df443b..74964888 100644
--- a/src/wat-writer.cc
+++ b/src/wat-writer.cc
@@ -558,7 +558,6 @@ class WatWriter::ExprVisitorDelegate : public ExprVisitor::Delegate {
   Result OnUnreachableExpr(UnreachableExpr*) override;
   Result BeginTryExpr(TryExpr*) override;
   Result OnCatchExpr(TryExpr*, Catch*) override;
-  Result OnUnwindExpr(TryExpr*) override;
   Result OnDelegateExpr(TryExpr*) override;
   Result EndTryExpr(TryExpr*) override;
   Result OnThrowExpr(ThrowExpr*) override;
@@ -894,14 +893,6 @@ Result WatWriter::ExprVisitorDelegate::OnCatchExpr(
   return Result::Ok;
 }
 
-Result WatWriter::ExprVisitorDelegate::OnUnwindExpr(TryExpr* expr) {
-  writer_->Dedent();
-  writer_->WritePutsNewline(Opcode::Unwind_Opcode.GetName());
-  writer_->Indent();
-  writer_->SetTopLabelType(LabelType::Unwind);
-  return Result::Ok;
-}
-
 Result WatWriter::ExprVisitorDelegate::OnDelegateExpr(TryExpr* expr) {
   writer_->Dedent();
   writer_->EndBlock();
@@ -1174,14 +1165,6 @@ void WatWriter::FlushExprTree(const ExprTree& expr_tree) {
             WriteCloseNewline();
           }
           break;
-        case TryKind::Unwind:
-          WritePuts("(", NextChar::None);
-          WritePutsNewline(Opcode::Unwind_Opcode.GetName());
-          Indent();
-          WriteFoldedExprList(try_expr->unwind);
-          FlushExprTreeStack();
-          WriteCloseNewline();
-          break;
         case TryKind::Delegate:
           WritePuts("(", NextChar::None);
           WritePutsSpace(Opcode::Delegate_Opcode.GetName());
diff --git a/test/dump/try-unwind.txt b/test/dump/try-unwind.txt
deleted file mode 100644
index 50d3af2a..00000000
--- a/test/dump/try-unwind.txt
+++ /dev/null
@@ -1,90 +0,0 @@
-;;; TOOL: run-objdump
-;;; ARGS0: -v --enable-exceptions
-(module
-  (tag $e (param i32))
-  (func
-    try $try1 (result i32)
-      nop
-      i32.const 7
-    unwind
-      i32.const 8
-      drop
-    end
-    drop))
-(;; STDERR ;;;
-0000000: 0061 736d                                 ; WASM_BINARY_MAGIC
-0000004: 0100 0000                                 ; WASM_BINARY_VERSION
-; section "Type" (1)
-0000008: 01                                        ; section code
-0000009: 00                                        ; section size (guess)
-000000a: 02                                        ; num types
-; func type 0
-000000b: 60                                        ; func
-000000c: 01                                        ; num params
-000000d: 7f                                        ; i32
-000000e: 00                                        ; num results
-; func type 1
-000000f: 60                                        ; func
-0000010: 00                                        ; num params
-0000011: 00                                        ; num results
-0000009: 08                                        ; FIXUP section size
-; section "Function" (3)
-0000012: 03                                        ; section code
-0000013: 00                                        ; section size (guess)
-0000014: 01                                        ; num functions
-0000015: 01                                        ; function 0 signature index
-0000013: 02                                        ; FIXUP section size
-; section "Tag" (13)
-0000016: 0d                                        ; section code
-0000017: 00                                        ; section size (guess)
-0000018: 01                                        ; tag count
-; tag 0
-0000019: 00                                        ; tag attribute
-000001a: 00                                        ; tag signature index
-0000017: 03                                        ; FIXUP section size
-; section "DataCount" (12)
-000001b: 0c                                        ; section code
-000001c: 00                                        ; section size (guess)
-000001d: 00                                        ; data count
-000001c: 01                                        ; FIXUP section size
-; section "Code" (10)
-000001e: 0a                                        ; section code
-000001f: 00                                        ; section size (guess)
-0000020: 01                                        ; num functions
-; function body 0
-0000021: 00                                        ; func body size (guess)
-0000022: 00                                        ; local decl count
-0000023: 06                                        ; try
-0000024: 7f                                        ; i32
-0000025: 01                                        ; nop
-0000026: 41                                        ; i32.const
-0000027: 07                                        ; i32 literal
-0000028: 0a                                        ; unwind
-0000029: 41                                        ; i32.const
-000002a: 08                                        ; i32 literal
-000002b: 1a                                        ; drop
-000002c: 0b                                        ; end
-000002d: 1a                                        ; drop
-000002e: 0b                                        ; end
-0000021: 0d                                        ; FIXUP func body size
-000001f: 0f                                        ; FIXUP section size
-; move data: [1e, 2f) -> [1b, 2c)
-; truncate to 44 (0x2c)
-;;; STDERR ;;)
-(;; STDOUT ;;;
-
-try-unwind.wasm:	file format wasm 0x1
-
-Code Disassembly:
-
-00001f func[0]:
- 000020: 06 7f                      | try i32
- 000022: 01                         |   nop
- 000023: 41 07                      |   i32.const 7
- 000025: 0a                         | unwind
- 000026: 41 08                      |   i32.const 8
- 000028: 1a                         |   drop
- 000029: 0b                         | end
- 00002a: 1a                         | drop
- 00002b: 0b                         | end
-;;; STDOUT ;;)
diff --git a/test/parse/expr/bad-try-no-catch.txt b/test/parse/expr/bad-try-no-catch.txt
index a1e5ebde..c85756fb 100644
--- a/test/parse/expr/bad-try-no-catch.txt
+++ b/test/parse/expr/bad-try-no-catch.txt
@@ -5,7 +5,7 @@
   (func try nop end)
   (func (try (do nop))))
 (;; STDERR ;;;
-out/test/parse/expr/bad-try-no-catch.txt:5:17: error: unexpected token "end", expected catch, catch_all, unwind or delegate.
+out/test/parse/expr/bad-try-no-catch.txt:5:17: error: unexpected token "end", expected catch, catch_all or delegate.
   (func try nop end)
                 ^^^
 out/test/parse/expr/bad-try-no-catch.txt:6:22: error: unexpected token ), expected (.
diff --git a/test/parse/expr/bad-try-unwind.txt b/test/parse/expr/bad-try-unwind.txt
deleted file mode 100644
index 7790c6eb..00000000
--- a/test/parse/expr/bad-try-unwind.txt
+++ /dev/null
@@ -1,38 +0,0 @@
-;;; TOOL: wat2wasm
-;;; ARGS: --enable-exceptions
-;;; ERROR: 1
-(module
-  (func try nop unwind)
-
-  (func
-    try
-      nop
-    unwind
-      nop
-    catch 0
-      nop
-    end)
-
-  ;; folded
-  (func
-    (try
-      (do
-        (nop))
-      (unwind
-        (nop))
-      (catch 0
-        (nop)))
-(;; STDERR ;;;
-out/test/parse/expr/bad-try-unwind.txt:5:23: error: unexpected token ), expected end.
-  (func try nop unwind)
-                      ^
-out/test/parse/expr/bad-try-unwind.txt:12:5: error: unexpected token catch, expected end.
-    catch 0
-    ^^^^^
-out/test/parse/expr/bad-try-unwind.txt:14:5: error: unexpected token end, expected ).
-    end)
-    ^^^
-out/test/parse/expr/bad-try-unwind.txt:23:8: error: unexpected token "catch", expected a valid try clause.
-      (catch 0
-       ^^^^^
-;;; STDERR ;;)
diff --git a/test/parse/expr/try-unwind.txt b/test/parse/expr/try-unwind.txt
deleted file mode 100644
index 4eb9f5e1..00000000
--- a/test/parse/expr/try-unwind.txt
+++ /dev/null
@@ -1,15 +0,0 @@
-;;; TOOL: wat2wasm
-;;; ARGS: --enable-exceptions
-(module
-  (func
-    try
-      nop
-    unwind
-    end)
-
-  (func
-    try (result i32)
-      (i32.const 1)
-    unwind
-    end
-    drop))
diff --git a/test/roundtrip/fold-try-unwind.txt b/test/roundtrip/fold-try-unwind.txt
deleted file mode 100644
index fbfb625a..00000000
--- a/test/roundtrip/fold-try-unwind.txt
+++ /dev/null
@@ -1,25 +0,0 @@
-;;; TOOL: run-roundtrip
-;;; ARGS: --stdout --fold-exprs --enable-exceptions --debug-names
-(module
-  (func (result i32)
-    try (result i32)
-      nop
-      i32.const 7
-    unwind
-      i32.const 8
-      drop
-    end
-  )
-)
-(;; STDOUT ;;;
-(module
-  (type (;0;) (func (result i32)))
-  (func (;0;) (type 0) (result i32)
-    (try (result i32)  ;; label = @1
-      (do
-        (nop)
-        (i32.const 7))
-      (unwind
-        (drop
-          (i32.const 8))))))
-;;; STDOUT ;;)
diff --git a/test/typecheck/bad-rethrow-depth.txt b/test/typecheck/bad-rethrow-depth.txt
index 571ae130..2b4bc890 100644
--- a/test/typecheck/bad-rethrow-depth.txt
+++ b/test/typecheck/bad-rethrow-depth.txt
@@ -23,12 +23,6 @@
         end
       end
     end)
-
-  (func
-    try
-    unwind
-      rethrow 0
-    end)
   )
 (;; STDERR ;;;
 out/test/typecheck/bad-rethrow-depth.txt:15:13: error: invalid rethrow depth: 0 (catches: 1, 3)
@@ -49,7 +43,4 @@ out/test/typecheck/bad-rethrow-depth.txt:20:13: error: invalid rethrow depth: 2
 out/test/typecheck/bad-rethrow-depth.txt:21:13: error: invalid rethrow depth: 2 (catches: 0, 1, 3)
             rethrow 2
             ^^^^^^^
-out/test/typecheck/bad-rethrow-depth.txt:30:7: error: rethrow not in try catch block
-      rethrow 0
-      ^^^^^^^
 ;;; STDERR ;;)