4 files changed, 30 insertions, 2 deletions

diff --git a/src/wasm/wasm-binary.cpp b/src/wasm/wasm-binary.cpp
index f1c6eeb7c..d15ac493f 100644
--- a/src/wasm/wasm-binary.cpp
+++ b/src/wasm/wasm-binary.cpp
@@ -679,6 +679,8 @@ void WasmBinaryWriter::writeFeaturesSection() {
         return BinaryConsts::UserSections::SignExtFeature;
       case FeatureSet::ExceptionHandling:
         return BinaryConsts::UserSections::ExceptionHandlingFeature;
+      case FeatureSet::TailCall:
+        return BinaryConsts::UserSections::TailCallFeature;
       default:
         WASM_UNREACHABLE();
     }
@@ -2162,6 +2164,8 @@ void WasmBinaryBuilder::readFeatures(size_t payloadLen) {
         wasm.features.setSignExt();
       } else if (name == BinaryConsts::UserSections::SIMD128Feature) {
         wasm.features.setSIMD();
+      } else if (name == BinaryConsts::UserSections::TailCallFeature) {
+        wasm.features.setTailCall();
       }
     }
   }
@@ -2210,6 +2214,20 @@ BinaryConsts::ASTNodes WasmBinaryBuilder::readExpression(Expression*& curr) {
       visitCallIndirect(
         (curr = allocator.alloc<CallIndirect>())->cast<CallIndirect>());
       break;
+    case BinaryConsts::RetCallFunction: {
+      auto call = allocator.alloc<Call>();
+      call->isReturn = true;
+      curr = call;
+      visitCall(call);
+      break;
+    }
+    case BinaryConsts::RetCallIndirect: {
+      auto call = allocator.alloc<CallIndirect>();
+      call->isReturn = true;
+      curr = call;
+      visitCallIndirect(call);
+      break;
+    }
     case BinaryConsts::LocalGet:
       visitLocalGet((curr = allocator.alloc<LocalGet>())->cast<LocalGet>());
       break;
diff --git a/src/wasm/wasm-s-parser.cpp b/src/wasm/wasm-s-parser.cpp
index 04c31815f..7a2d8a009 100644
--- a/src/wasm/wasm-s-parser.cpp
+++ b/src/wasm/wasm-s-parser.cpp
@@ -1622,17 +1622,19 @@ Expression* SExpressionWasmBuilder::makeLoop(Element& s) {
   return ret;
 }
 
-Expression* SExpressionWasmBuilder::makeCall(Element& s) {
+Expression* SExpressionWasmBuilder::makeCall(Element& s, bool isReturn) {
   auto target = getFunctionName(*s[1]);
   auto ret = allocator.alloc<Call>();
   ret->target = target;
   ret->type = functionTypes[ret->target];
   parseCallOperands(s, 2, s.size(), ret);
+  ret->isReturn = isReturn;
   ret->finalize();
   return ret;
 }
 
-Expression* SExpressionWasmBuilder::makeCallIndirect(Element& s) {
+Expression* SExpressionWasmBuilder::makeCallIndirect(Element& s,
+                                                     bool isReturn) {
   if (!wasm.table.exists) {
     throw ParseException("no table");
   }
@@ -1645,6 +1647,7 @@ Expression* SExpressionWasmBuilder::makeCallIndirect(Element& s) {
   ret->type = functionType->result;
   parseCallOperands(s, i, s.size() - 1, ret);
   ret->target = parseExpression(s[s.size() - 1]);
+  ret->isReturn = isReturn;
   ret->finalize();
   return ret;
 }
diff --git a/src/wasm/wasm-validator.cpp b/src/wasm/wasm-validator.cpp
index 1d12c2452..01cb1e2a8 100644
--- a/src/wasm/wasm-validator.cpp
+++ b/src/wasm/wasm-validator.cpp
@@ -569,6 +569,9 @@ void FunctionValidator::visitSwitch(Switch* curr) {
 }
 
 void FunctionValidator::visitCall(Call* curr) {
+  shouldBeTrue(!curr->isReturn || getModule()->features.hasTailCall(),
+               curr,
+               "return_call requires tail calls to be enabled");
   if (!info.validateGlobally) {
     return;
   }
@@ -593,6 +596,9 @@ void FunctionValidator::visitCall(Call* curr) {
 }
 
 void FunctionValidator::visitCallIndirect(CallIndirect* curr) {
+  shouldBeTrue(!curr->isReturn || getModule()->features.hasTailCall(),
+               curr,
+               "return_call_indirect requires tail calls to be enabled");
   if (!info.validateGlobally) {
     return;
   }
diff --git a/src/wasm/wasm.cpp b/src/wasm/wasm.cpp
index a307d95f4..e4c9813b3 100644
--- a/src/wasm/wasm.cpp
+++ b/src/wasm/wasm.cpp
@@ -40,6 +40,7 @@ const char* MutableGlobalsFeature = "mutable-globals";
 const char* TruncSatFeature = "nontrapping-fptoint";
 const char* SignExtFeature = "sign-ext";
 const char* SIMD128Feature = "simd128";
+const char* TailCallFeature = "tail-call";
 } // namespace UserSections
 } // namespace BinaryConsts