[wasm] Let BranchTableIterator::has_next return false if decoder->failed()

src/wasm/ast-decoder.h

Index: src/wasm/ast-decoder.h
diff --git a/src/wasm/ast-decoder.h b/src/wasm/ast-decoder.h
index 001dfb4c5c292713c6744d9448aac366ac76926c..74e05841dd57649ba3ba9b710874ef4d4b73ca55 100644
--- a/src/wasm/ast-decoder.h
+++ b/src/wasm/ast-decoder.h
@@ -234,7 +234,7 @@ struct BranchTableOperand {
 class BranchTableIterator {
  public:
   unsigned cur_index() { return index_; }
-  bool has_next() { return index_ <= table_count_; }
+  bool has_next() { return decoder_->ok() && index_ <= table_count_; }

[titzer, 2016/10/13 13:46:10]

Does this obviate the previous fix?

[ahaas, 2016/10/13 13:53:44]

This change does not prevent any crashes, it just reduces the time it takes to
decode an invalid function.

   uint32_t next() {
     DCHECK(has_next());
     index_++;