Implement Multi-tier JIT (#1774)

Implement 2-level Multi-tier JIT engine: tier-up from Fast JIT to LLVM JIT to
get quick cold startup by Fast JIT and better performance by gradually
switching to LLVM JIT when the LLVM JIT functions are compiled by the
backend threads.

Refer to:
https://github.com/bytecodealliance/wasm-micro-runtime/issues/1302

core/iwasm/fast-jit/jit_frontend.h

@@ -13,6 +13,10 @@
 #include "../aot/aot_runtime.h"
 #endif
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #if WASM_ENABLE_AOT == 0
 typedef enum IntCond {
     INT_EQZ = 0,
@@ -143,6 +147,9 @@ jit_frontend_translate_func(JitCompContext *cc);
 bool
 jit_frontend_lower(JitCompContext *cc);
 
+uint32
+jit_frontend_get_jitted_return_addr_offset();
+
 uint32
 jit_frontend_get_global_data_offset(const WASMModule *module,
                                     uint32 global_idx);
@@ -483,4 +490,8 @@ set_local_f64(JitFrame *frame, int n, JitReg val)
 #define PUSH_FUNCREF(v) PUSH(v, VALUE_TYPE_FUNCREF)
 #define PUSH_EXTERNREF(v) PUSH(v, VALUE_TYPE_EXTERNREF)
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif