2 files changed, 31 insertions, 2 deletions

diff --git a/src/parser/contexts.h b/src/parser/contexts.h
index 7eedcccc2..862d9772d 100644
--- a/src/parser/contexts.h
+++ b/src/parser/contexts.h
@@ -279,6 +279,7 @@ struct NullInstrParserCtx {
   using GlobalIdxT = Ok;
   using MemoryIdxT = Ok;
   using DataIdxT = Ok;
+  using LabelIdxT = Ok;
 
   using MemargT = Ok;
 
@@ -298,6 +299,8 @@ struct NullInstrParserCtx {
   MemoryIdxT getMemoryFromName(Name) { return Ok{}; }
   DataIdxT getDataFromIdx(uint32_t) { return Ok{}; }
   DataIdxT getDataFromName(Name) { return Ok{}; }
+  LabelIdxT getLabelFromIdx(uint32_t) { return Ok{}; }
+  LabelIdxT getLabelFromName(Name) { return Ok{}; }
 
   MemargT getMemarg(uint64_t, uint32_t) { return Ok{}; }
 
@@ -370,7 +373,7 @@ struct NullInstrParserCtx {
 
   Result<> makeMemoryCopy(Index, MemoryIdxT*, MemoryIdxT*) { return Ok{}; }
   Result<> makeMemoryFill(Index, MemoryIdxT*) { return Ok{}; }
-
+  Result<> makeBreak(Index, LabelIdxT) { return Ok{}; }
   Result<> makeReturn(Index) { return Ok{}; }
   template<typename HeapTypeT> Result<> makeRefNull(Index, HeapTypeT) {
     return Ok{};
@@ -793,6 +796,7 @@ struct ParseDefsCtx : TypeParserCtx<ParseDefsCtx> {
 
   using FieldIdxT = Index;
   using LocalIdxT = Index;
+  using LabelIdxT = Index;
   using GlobalIdxT = Name;
   using MemoryIdxT = Name;
   using DataIdxT = Name;
@@ -936,6 +940,12 @@ struct ParseDefsCtx : TypeParserCtx<ParseDefsCtx> {
     return name;
   }
 
+  Result<Index> getLabelFromIdx(uint32_t idx) { return idx; }
+
+  Result<Index> getLabelFromName(Name name) {
+    return irBuilder.getLabelIndex(name);
+  }
+
   Result<TypeUseT> makeTypeUse(Index pos,
                                std::optional<HeapTypeT> type,
                                ParamsT* params,
@@ -1203,6 +1213,10 @@ struct ParseDefsCtx : TypeParserCtx<ParseDefsCtx> {
     return withLoc(pos, irBuilder.makeMemoryFill(*m));
   }
 
+  Result<> makeBreak(Index pos, Index label) {
+    return withLoc(pos, irBuilder.makeBreak(label));
+  }
+
   Result<> makeReturn(Index pos) {
     return withLoc(pos, irBuilder.makeReturn());
   }
diff --git a/src/parser/parsers.h b/src/parser/parsers.h
index 38005253f..32f6709df 100644
--- a/src/parser/parsers.h
+++ b/src/parser/parsers.h
@@ -177,6 +177,7 @@ template<typename Ctx> Result<typename Ctx::MemoryIdxT> memidx(Ctx&);
 template<typename Ctx> MaybeResult<typename Ctx::MemoryIdxT> maybeMemuse(Ctx&);
 template<typename Ctx> Result<typename Ctx::GlobalIdxT> globalidx(Ctx&);
 template<typename Ctx> Result<typename Ctx::LocalIdxT> localidx(Ctx&);
+template<typename Ctx> Result<typename Ctx::LabelIdxT> labelidx(Ctx&);
 template<typename Ctx> Result<typename Ctx::TypeUseT> typeuse(Ctx&);
 MaybeResult<ImportNames> inlineImport(ParseInput&);
 Result<std::vector<Name>> inlineExports(ParseInput&);
@@ -1195,7 +1196,9 @@ Result<> makeCallIndirect(Ctx& ctx, Index pos, bool isReturn) {
 }
 
 template<typename Ctx> Result<> makeBreak(Ctx& ctx, Index pos) {
-  return ctx.in.err("unimplemented instruction");
+  auto label = labelidx(ctx);
+  CHECK_ERR(label);
+  return ctx.makeBreak(pos, *label);
 }
 
 template<typename Ctx> Result<> makeBreakTable(Ctx& ctx, Index pos) {
@@ -1569,6 +1572,18 @@ template<typename Ctx> Result<typename Ctx::LocalIdxT> localidx(Ctx& ctx) {
   return ctx.in.err("expected local index or identifier");
 }
 
+// labelidx ::= x:u32 => x
+//            | v:id => x (if labels[x] = v)
+template<typename Ctx> Result<typename Ctx::LabelIdxT> labelidx(Ctx& ctx) {
+  if (auto x = ctx.in.takeU32()) {
+    return ctx.getLabelFromIdx(*x);
+  }
+  if (auto id = ctx.in.takeID()) {
+    return ctx.getLabelFromName(*id);
+  }
+  return ctx.in.err("expected label index or identifier");
+}
+
 // typeuse ::= '(' 'type' x:typeidx ')'                                => x, []
 //                 (if typedefs[x] = [t1*] -> [t2*]
 //           | '(' 'type' x:typeidx ')' ((t1,IDs):param)* (t2:result)* => x, IDs