3 files changed, 55 insertions, 45 deletions

diff --git a/src/ir/eh-utils.cpp b/src/ir/eh-utils.cpp
index 37af738ce..3d369573d 100644
--- a/src/ir/eh-utils.cpp
+++ b/src/ir/eh-utils.cpp
@@ -107,54 +107,56 @@ bool containsValidDanglingPop(Expression* catchBody) {
   return pop != nullptr && !isPopNested;
 }
 
+void handleBlockNestedPop(Try* try_, Function* func, Module& wasm) {
+  Builder builder(wasm);
+  for (Index i = 0; i < try_->catchTags.size(); i++) {
+    Name tagName = try_->catchTags[i];
+    auto* tag = wasm.getTag(tagName);
+    if (tag->sig.params == Type::none) {
+      continue;
+    }
+
+    auto* catchBody = try_->catchBodies[i];
+    bool isPopNested = false;
+    Expression** popPtr = nullptr;
+    Expression* pop = getFirstPop(catchBody, isPopNested, popPtr);
+    assert(pop && "Pop has not been found in this catch");
+
+    // Change code like
+    // (catch $e
+    //   ...
+    //   (block
+    //     (pop i32)
+    //   )
+    // )
+    // into
+    // (catch $e
+    //   (local.set $new
+    //     (pop i32)
+    //   )
+    //   ...
+    //   (block
+    //     (local.get $new)
+    //   )
+    // )
+    if (isPopNested) {
+      assert(popPtr);
+      Index newLocal = builder.addVar(func, pop->type);
+      try_->catchBodies[i] =
+        builder.makeSequence(builder.makeLocalSet(newLocal, pop), catchBody);
+      *popPtr = builder.makeLocalGet(newLocal, pop->type);
+    }
+  }
+}
+
 void handleBlockNestedPops(Function* func, Module& wasm) {
   if (!wasm.features.hasExceptionHandling()) {
     return;
   }
-
-  Builder builder(wasm);
   FindAll<Try> trys(func->body);
   for (auto* try_ : trys.list) {
-    for (Index i = 0; i < try_->catchTags.size(); i++) {
-      Name tagName = try_->catchTags[i];
-      auto* tag = wasm.getTag(tagName);
-      if (tag->sig.params == Type::none) {
-        continue;
-      }
-
-      auto* catchBody = try_->catchBodies[i];
-      bool isPopNested = false;
-      Expression** popPtr = nullptr;
-      Expression* pop = getFirstPop(catchBody, isPopNested, popPtr);
-      assert(pop && "Pop has not been found in this catch");
-
-      // Change code like
-      // (catch $e
-      //   ...
-      //   (block
-      //     (pop i32)
-      //   )
-      // )
-      // into
-      // (catch $e
-      //   (local.set $new
-      //     (pop i32)
-      //   )
-      //   ...
-      //   (block
-      //     (local.get $new)
-      //   )
-      // )
-      if (isPopNested) {
-        assert(popPtr);
-        Index newLocal = builder.addVar(func, pop->type);
-        try_->catchBodies[i] =
-          builder.makeSequence(builder.makeLocalSet(newLocal, pop), catchBody);
-        *popPtr = builder.makeLocalGet(newLocal, pop->type);
-      }
-    }
+    handleBlockNestedPop(try_, func, wasm);
   }
-
   // Pops we handled can be of non-defaultable types, so we may have created
   // non-nullable type locals. Fix them.
   TypeUpdating::handleNonDefaultableLocals(func, wasm);
diff --git a/src/ir/eh-utils.h b/src/ir/eh-utils.h
index c0d6e59ea..25677a32e 100644
--- a/src/ir/eh-utils.h
+++ b/src/ir/eh-utils.h
@@ -31,10 +31,13 @@ namespace EHUtils {
 //   catch body, which is invalid. That will be taken care of in validation.
 bool containsValidDanglingPop(Expression* catchBody);
 
-// Fixes up 'pop's nested in blocks, which are currently not supported without
-// block param types, by creating a new local, putting a (local.set $new (pop
-// type)) right after 'catch', and putting a '(local.get $new)' where the 'pop'
-// used to be.
+// Given a 'Try' expression, fixes up 'pop's nested in blocks, which are
+// currently not supported without block param types, by creating a new local,
+// putting a (local.set $new (pop type)) right after 'catch', and putting a
+// '(local.get $new)' where the 'pop' used to be.
+void handleBlockNestedPop(Try* try_, Function* func, Module& wasm);
+
+// Calls handleBlockNestedPop for each 'Try's in a given function.
 void handleBlockNestedPops(Function* func, Module& wasm);
 
 } // namespace EHUtils
diff --git a/src/wasm/wasm-binary.cpp b/src/wasm/wasm-binary.cpp
index d8a3c2f74..57a2bc95c 100644
--- a/src/wasm/wasm-binary.cpp
+++ b/src/wasm/wasm-binary.cpp
@@ -17,6 +17,7 @@
 #include <algorithm>
 #include <fstream>
 
+#include "ir/eh-utils.h"
 #include "ir/module-utils.h"
 #include "ir/table-utils.h"
 #include "ir/type-updating.h"
@@ -6419,6 +6420,10 @@ void WasmBinaryBuilder::visitTryOrTryInBlock(Expression*& out) {
     }
     exceptionTargetNames.erase(catchLabel);
   }
+
+  // If catch bodies contained stacky code, 'pop's can be nested within a block.
+  // Fix that up.
+  EHUtils::handleBlockNestedPop(curr, currFunction, wasm);
   curr->finalize(curr->type);
 
   // For simplicity, we create an inner block within the catch body too, but the