[wasm] Adding feature to JIT a wasm function at runtime and hook up the compiled code into the indi…

src/wasm/ast-decoder.h

Index: src/wasm/ast-decoder.h
diff --git a/src/wasm/ast-decoder.h b/src/wasm/ast-decoder.h
index 40363a2cdba6e513a537811864a8acc857192460..a0e98f7587ab227b3f4e7ffae8f3106024a1f9f9 100644
--- a/src/wasm/ast-decoder.h
+++ b/src/wasm/ast-decoder.h
@@ -150,6 +150,16 @@ struct CallImportOperand {
   }
 };
 
+struct JITSingleFunctionOperand {
+  uint32_t sig_index;
+  FunctionSig* sig;
+  unsigned length;
+  inline JITSingleFunctionOperand(Decoder* decoder, const byte* pc) {
+    sig_index = decoder->checked_read_u32v(pc, 1, &length, "signature index");
+    sig = nullptr;
+  }
+};
+
 struct BranchTableOperand {
   uint32_t arity;
   uint32_t table_count;