5 files changed, 97 insertions, 0 deletions
diff --git a/src/wasm/wasm-binary.cpp b/src/wasm/wasm-binary.cpp
index e61fd1e27..59276124e 100644
--- a/src/wasm/wasm-binary.cpp
+++ b/src/wasm/wasm-binary.cpp
@@ -3951,6 +3951,12 @@ BinaryConsts::ASTNodes WasmBinaryBuilder::readExpression(Expression*& curr) {
       if (maybeVisitStringIterMove(curr, opcode)) {
         break;
       }
+      if (maybeVisitStringSliceWTF(curr, opcode)) {
+        break;
+      }
+      if (maybeVisitStringSliceIter(curr, opcode)) {
+        break;
+      }
       if (opcode == BinaryConsts::RefIsFunc ||
           opcode == BinaryConsts::RefIsData ||
           opcode == BinaryConsts::RefIsI31) {
@@ -7329,6 +7335,34 @@ bool WasmBinaryBuilder::maybeVisitStringIterMove(Expression*& out,
   return true;
 }
 
+bool WasmBinaryBuilder::maybeVisitStringSliceWTF(Expression*& out,
+                                                 uint32_t code) {
+  StringSliceWTFOp op;
+  if (code == BinaryConsts::StringViewWTF8Slice) {
+    op = StringSliceWTF8;
+  } else if (code == BinaryConsts::StringViewWTF16Slice) {
+    op = StringSliceWTF16;
+  } else {
+    return false;
+  }
+  auto* end = popNonVoidExpression();
+  auto* start = popNonVoidExpression();
+  auto* ref = popNonVoidExpression();
+  out = Builder(wasm).makeStringSliceWTF(op, ref, start, end);
+  return true;
+}
+
+bool WasmBinaryBuilder::maybeVisitStringSliceIter(Expression*& out,
+                                                  uint32_t code) {
+  if (code != BinaryConsts::StringViewIterSlice) {
+    return false;
+  }
+  auto* num = popNonVoidExpression();
+  auto* ref = popNonVoidExpression();
+  out = Builder(wasm).makeStringSliceIter(ref, num);
+  return true;
+}
+
 void WasmBinaryBuilder::visitRefAs(RefAs* curr, uint8_t code) {
   BYN_TRACE("zz node: RefAs\n");
   switch (code) {
diff --git a/src/wasm/wasm-s-parser.cpp b/src/wasm/wasm-s-parser.cpp
index 905c77523..f3bafe3de 100644
--- a/src/wasm/wasm-s-parser.cpp
+++ b/src/wasm/wasm-s-parser.cpp
@@ -3024,6 +3024,17 @@ Expression* SExpressionWasmBuilder::makeStringIterMove(Element& s,
     op, parseExpression(s[1]), parseExpression(s[2]));
 }
 
+Expression* SExpressionWasmBuilder::makeStringSliceWTF(Element& s,
+                                                       StringSliceWTFOp op) {
+  return Builder(wasm).makeStringSliceWTF(
+    op, parseExpression(s[1]), parseExpression(s[2]), parseExpression(s[3]));
+}
+
+Expression* SExpressionWasmBuilder::makeStringSliceIter(Element& s) {
+  return Builder(wasm).makeStringSliceIter(parseExpression(s[1]),
+                                           parseExpression(s[2]));
+}
+
 // converts an s-expression string representing binary data into an output
 // sequence of raw bytes this appends to data, which may already contain
 // content.
diff --git a/src/wasm/wasm-stack.cpp b/src/wasm/wasm-stack.cpp
index 731f47568..3707848d1 100644
--- a/src/wasm/wasm-stack.cpp
+++ b/src/wasm/wasm-stack.cpp
@@ -2357,6 +2357,25 @@ void BinaryInstWriter::visitStringIterMove(StringIterMove* curr) {
   }
 }
 
+void BinaryInstWriter::visitStringSliceWTF(StringSliceWTF* curr) {
+  o << int8_t(BinaryConsts::GCPrefix);
+  switch (curr->op) {
+    case StringSliceWTF8:
+      o << U32LEB(BinaryConsts::StringViewWTF8Slice);
+      break;
+    case StringSliceWTF16:
+      o << U32LEB(BinaryConsts::StringViewWTF16Slice);
+      break;
+    default:
+      WASM_UNREACHABLE("invalid string.move*");
+  }
+}
+
+void BinaryInstWriter::visitStringSliceIter(StringSliceIter* curr) {
+  o << int8_t(BinaryConsts::GCPrefix)
+    << U32LEB(BinaryConsts::StringViewIterSlice);
+}
+
 void BinaryInstWriter::emitScopeEnd(Expression* curr) {
   assert(!breakStack.empty());
   breakStack.pop_back();
diff --git a/src/wasm/wasm.cpp b/src/wasm/wasm.cpp
index c4a5f362a..0a3ca1929 100644
--- a/src/wasm/wasm.cpp
+++ b/src/wasm/wasm.cpp
@@ -1269,6 +1269,23 @@ void StringIterMove::finalize() {
   }
 }
 
+void StringSliceWTF::finalize() {
+  if (ref->type == Type::unreachable || start->type == Type::unreachable ||
+      end->type == Type::unreachable) {
+    type = Type::unreachable;
+  } else {
+    type = Type(HeapType::string, NonNullable);
+  }
+}
+
+void StringSliceIter::finalize() {
+  if (ref->type == Type::unreachable || num->type == Type::unreachable) {
+    type = Type::unreachable;
+  } else {
+    type = Type(HeapType::string, NonNullable);
+  }
+}
+
 size_t Function::getNumParams() { return getParams().size(); }
 
 size_t Function::getNumVars() { return vars.size(); }
diff --git a/src/wasm/wat-parser.cpp b/src/wasm/wat-parser.cpp
index 07503974d..e3a2ab588 100644
--- a/src/wasm/wat-parser.cpp
+++ b/src/wasm/wat-parser.cpp
@@ -1027,6 +1027,11 @@ Result<typename Ctx::InstrT> makeStringIterNext(Ctx&, ParseInput&);
 template<typename Ctx>
 Result<typename Ctx::InstrT>
 makeStringIterMove(Ctx&, ParseInput&, StringIterMoveOp op);
+template<typename Ctx>
+Result<typename Ctx::InstrT>
+makeStringSliceWTF(Ctx&, ParseInput&, StringSliceWTFOp op);
+template<typename Ctx>
+Result<typename Ctx::InstrT> makeStringSliceIter(Ctx&, ParseInput&);
 
 // Modules
 template<typename Ctx>
@@ -1924,6 +1929,17 @@ makeStringIterMove(Ctx& ctx, ParseInput& in, StringIterMoveOp op) {
   return in.err("unimplemented instruction");
 }
 
+template<typename Ctx>
+Result<typename Ctx::InstrT>
+makeStringSliceWTF(Ctx& ctx, ParseInput& in, StringSliceWTFOp op) {
+  return in.err("unimplemented instruction");
+}
+
+template<typename Ctx>
+Result<typename Ctx::InstrT> makeStringSliceIter(Ctx& ctx, ParseInput& in) {
+  return in.err("unimplemented instruction");
+}
+
 // =======
 // Modules
 // =======