Calculate func_index instead of adding an extra field to wasm frame

Author: Georgii Rylov

core/iwasm/interpreter/wasm_interp.h

@@ -26,8 +26,6 @@ typedef struct WASMInterpFrame {
     /* Instruction pointer of the bytecode array.  */
     uint8 *ip;
 
-    uint32 func_index;
-
 #if WASM_ENABLE_FAST_JIT != 0
     uint8 *jitted_return_addr;
 #endif

core/iwasm/interpreter/wasm_interp_classic.c

@@ -1264,11 +1264,9 @@ wasm_interp_call_func_native(WASMModuleInstance *module_inst,
     init_frame_refs(frame_ref, local_cell_num, cur_func);
 #endif
 
-    cur_func_index = (uint32)(cur_func - module_inst->e->functions);
-    frame->func_index = cur_func_index;
-
     wasm_exec_env_set_cur_frame(exec_env, frame);
 
+    cur_func_index = (uint32)(cur_func - module_inst->e->functions);
     bh_assert(cur_func_index < module_inst->module->import_function_count);
     if (!func_import->call_conv_wasm_c_api) {
         native_func_pointer = module_inst->import_func_ptrs[cur_func_index];

core/iwasm/interpreter/wasm_interp_fast.c

@@ -1205,11 +1205,9 @@ wasm_interp_call_func_native(WASMModuleInstance *module_inst,
     init_frame_refs(frame->frame_ref, local_cell_num, cur_func);
 #endif
 
-    cur_func_index = (uint32)(cur_func - module_inst->e->functions);
-    frame->func_index = cur_func_index;
-
     wasm_exec_env_set_cur_frame(exec_env, frame);
 
+    cur_func_index = (uint32)(cur_func - module_inst->e->functions);
     bh_assert(cur_func_index < module_inst->module->import_function_count);
     if (!func_import->call_conv_wasm_c_api) {
         native_func_pointer = module_inst->import_func_ptrs[cur_func_index];
@@ -6034,7 +6032,6 @@ wasm_interp_call_func_bytecode(WASMModuleInstance *module,
 
             /* Initialize the interpreter context. */
             frame->function = cur_func;
-            frame->func_index = (uint32)(cur_func - module->e->functions);
             frame_ip = wasm_get_func_code(cur_func);
             frame_ip_end = wasm_get_func_code_end(cur_func);
 

core/iwasm/interpreter/wasm_runtime.c

@@ -4222,7 +4222,8 @@ wasm_interp_iterate_callstack(WASMExecEnv *exec_env,
            && (uint8_t *)cur_frame + sizeof(WASMInterpFrame) <= top_boundary) {
         record_frame.instance = module_inst;
         record_frame.module_offset = 0;
-        record_frame.func_index = cur_frame->func_index;
+        // It's safe to dereference module_inst->e because "e" is asigned only once in wasm_instantiate
+        record_frame.func_index = (uint32)(cur_frame->function - module_inst->e->functions);
         if (!frame_handler(user_data, &record_frame)) {
             break;
         }