[wasm] Track in the interpreter if a NaN could have been produced.

src/wasm/wasm-interpreter.h

Index: src/wasm/wasm-interpreter.h
diff --git a/src/wasm/wasm-interpreter.h b/src/wasm/wasm-interpreter.h
index 2ed6053ddbd7787018912dfae3296739aebe5c9c..59a273f45b7620762ee82b1531362933e927b614 100644
--- a/src/wasm/wasm-interpreter.h
+++ b/src/wasm/wasm-interpreter.h
@@ -125,6 +125,7 @@ class V8_EXPORT_PRIVATE WasmInterpreter {
     virtual const WasmFrame* GetFrame(int index) = 0;
     virtual WasmFrame* GetMutableFrame(int index) = 0;
     virtual WasmVal GetReturnValue(int index = 0) = 0;
+    virtual bool MayProducedNaN() = 0;

[titzer, 2016/10/20 10:53:24]

Call this possibly nondeterministic? And add a comment to explain what it's for,
how it may be set, etc.

[ahaas, 2016/10/20 13:43:23]

Done.

 
     // Thread-specific breakpoints.
     bool SetBreakpoint(const WasmFunction* function, int pc, bool enabled);