[wasm] Validate the index of set local in AnalyzeLoopAssignment

src/wasm/ast-decoder.cc

Index: src/wasm/ast-decoder.cc
diff --git a/src/wasm/ast-decoder.cc b/src/wasm/ast-decoder.cc
index 798f9d393a5bf10dba8e1c5b5ebb944e1d0f171e..5d541705b21a580933307d9902a73d853d26fc3b 100644
--- a/src/wasm/ast-decoder.cc
+++ b/src/wasm/ast-decoder.cc
@@ -1850,10 +1850,12 @@ class WasmFullDecoder : public WasmDecoder {
           break;
         case kExprSetLocal: {
           LocalIndexOperand operand(this, pc);
-          if (assigned->length() > 0 &&
-              static_cast<int>(operand.index) < assigned->length()) {
-            // Unverified code might have an out-of-bounds index.
-            assigned->Add(operand.index);
+          if (Validate(pc_, operand)) {

[titzer, 2016/09/01 13:12:44]

I think if you just remove the static_cast to int, this will work. That was the
intention of the check, anyway.

[ahaas, 2016/09/01 13:53:15]

Done. I think that calling Validate() would have actually been an error because
Validate() causes an error state.

+            if (assigned->length() > 0 &&
+                static_cast<int>(operand.index) < assigned->length()) {
+              // Unverified code might have an out-of-bounds index.
+              assigned->Add(operand.index);
+            }
           }
           length = 1 + operand.length;
           break;