Validate finalization (#1014)

* validate that types are properly finalized, when in pass-debug mode (BINARYEN_PASS_DEBUG env var): check after each pass is run that the type of each node is equal to the proper type (when finalizing it, i.e., fully recomputing the type).

* fix many fuzz bugs found by that.

* in particular, fix dce bugs with type changes not being fully updated during code removal. add a new TypeUpdater helper class that lets a pass update types efficiently, by the helper tracking deps between blocks and branches etc., and updating/propagating type changes only as necessary.

1 files changed, 6 insertions, 0 deletions

diff --git a/src/passes/Precompute.cpp b/src/passes/Precompute.cpp
index 37686de1a..e06103c11 100644
--- a/src/passes/Precompute.cpp
+++ b/src/passes/Precompute.cpp
@@ -23,6 +23,7 @@
 #include <wasm-builder.h>
 #include <wasm-interpreter.h>
 #include <ast_utils.h>
+#include "ast/manipulation.h"
 
 namespace wasm {
 
@@ -142,6 +143,11 @@ struct Precompute : public WalkerPass<PostWalker<Precompute, UnifiedExpressionVi
       ExpressionManipulator::nop(curr);
     }
   }
+
+  void visitFunction(Function* curr) {
+    // removing breaks can alter types
+    ReFinalize().walkFunctionInModule(curr, getModule());
+  }
 };
 
 Pass *createPrecomputePass() {