Print parse errors in reducer and roundtrip (#3737)

Without this, crashes from things like #3736 simply get reported as
"a parse exception was thrown" with no detail.

1 files changed, 7 insertions, 1 deletions

diff --git a/src/tools/wasm-reduce.cpp b/src/tools/wasm-reduce.cpp
index 19afc2032..95e315e96 100644
--- a/src/tools/wasm-reduce.cpp
+++ b/src/tools/wasm-reduce.cpp
@@ -347,7 +347,13 @@ struct Reducer
   void loadWorking() {
     module = make_unique<Module>();
     ModuleReader reader;
-    reader.read(working, *module);
+    try {
+      reader.read(working, *module);
+    } catch (ParseException& p) {
+      p.dump(std::cerr);
+      std::cerr << '\n';
+      Fatal() << "error in parsing working wasm binary";
+    }
     // If there is no features section, assume we may need them all (without
     // this, a module with no features section but that uses e.g. atomics and
     // bulk memory would not work).