4 files changed, 12 insertions, 2 deletions
diff --git a/src/asm2wasm.h b/src/asm2wasm.h
index f6b6da43d..3ea9a3a1e 100644
--- a/src/asm2wasm.h
+++ b/src/asm2wasm.h
@@ -737,6 +737,9 @@ private:
 
 void Asm2WasmBuilder::processAsm(Ref ast) {
   assert(ast[0] == TOPLEVEL);
+  if (ast[1]->size() == 0) {
+    Fatal() << "empty input";
+  }
   Ref asmFunction = ast[1][0];
   assert(asmFunction[0] == DEFUN);
   Ref body = asmFunction[3];
diff --git a/src/ir/memory-utils.h b/src/ir/memory-utils.h
index 920583f7d..5980a3218 100644
--- a/src/ir/memory-utils.h
+++ b/src/ir/memory-utils.h
@@ -36,8 +36,8 @@ namespace MemoryUtils {
     }
     for (auto& segment : memory.segments) {
       auto* offset = segment.offset->dynCast<Const>();
-      auto start = offset->value.getInteger();
-      auto end = start + segment.data.size();
+      Index start = offset->value.getInteger();
+      Index end = start + segment.data.size();
       if (end > data.size()) {
         data.resize(end);
       }
diff --git a/src/tools/wasm-ctor-eval.cpp b/src/tools/wasm-ctor-eval.cpp
index dee342255..e11454b04 100644
--- a/src/tools/wasm-ctor-eval.cpp
+++ b/src/tools/wasm-ctor-eval.cpp
@@ -31,6 +31,7 @@
 #include "wasm-io.h"
 #include "wasm-interpreter.h"
 #include "wasm-builder.h"
+#include "wasm-validator.h"
 #include "ir/memory-utils.h"
 #include "ir/global-utils.h"
 #include "ir/import-utils.h"
@@ -412,6 +413,11 @@ int main(int argc, const char* argv[]) {
     }
   }
 
+  if (!WasmValidator().validate(wasm)) {
+    WasmPrinter::printModule(&wasm);
+    Fatal() << "error in validating input";
+  }
+
   // get list of ctors, and eval them
   std::vector<std::string> ctors;
   std::istringstream stream(ctorsString);
diff --git a/src/wasm/wasm-binary.cpp b/src/wasm/wasm-binary.cpp
index c60a3074a..5f4ace91b 100644
--- a/src/wasm/wasm-binary.cpp
+++ b/src/wasm/wasm-binary.cpp
@@ -1341,6 +1341,7 @@ void WasmBinaryBuilder::processExpressions() {
       if (pos == endOfFunction) {
         throwError("Reached function end without seeing End opcode");
       }
+      if (!more()) throwError("unexpected end of input");
       auto peek = input[pos];
       if (peek == BinaryConsts::End || peek == BinaryConsts::Else) {
         if (debug) std::cerr << "== processExpressions finished with unreachable" << std::endl;