Asyncify: Degrade gracefully if too many locals to compute relevantLiveLocals (#4108)

1 files changed, 9 insertions, 0 deletions

diff --git a/src/passes/Asyncify.cpp b/src/passes/Asyncify.cpp
index d0d03c9d1..dc2ebd4d4 100644
--- a/src/passes/Asyncify.cpp
+++ b/src/passes/Asyncify.cpp
@@ -1269,6 +1269,15 @@ private:
     };
 
     RelevantLiveLocalsWalker walker;
+    walker.setFunction(func);
+    if (!walker.canRun(func)) {
+      // We can proceed without this optimization, which will cause more
+      // spilling - assume all locals are relevant.
+      for (Index i = 0; i < func->getNumLocals(); i++) {
+        relevantLiveLocals.insert(i);
+      }
+      return;
+    }
     walker.walkFunctionInModule(func, getModule());
     // The relevant live locals are ones that are alive at an unwind/rewind
     // location. TODO look more precisely inside basic blocks, as one might stop