improve to check toolchain state

Author: waruqi

xmake/core/tool/toolchain.lua

@@ -208,6 +208,7 @@ end
 
 -- get the program and name of the given tool kind
 function _instance:tool(toolkind)
+    assert(self:_is_checked())
     -- ensure to do load for initializing toolset first
     -- @note we cannot call self:check() here, because it can only be called on config
     self:_load()
@@ -270,7 +271,8 @@ end
 -- do check, we only check it once for all architectures
 function _instance:check()
     local checkok = true
-    if not self._CHECKED then
+    local checked = self:_is_checked()
+    if not checked then
         local on_check = self:_on_check()
         if on_check then
             local ok, results_or_errors = sandbox.load(on_check, self)
@@ -280,7 +282,9 @@ function _instance:check()
                 os.raise(results_or_errors)
             end
         end
-        self._CHECKED = true
+        -- we need to persist this state
+        self:config_set("__checked", true)
+        self:configs_save()
     end
     return checkok
 end
@@ -374,6 +378,11 @@ function _instance:_is_loaded()
     return self:info():get("__loaded")
 end
 
+-- is checked?
+function _instance:_is_checked()
+    return self:config("__checked") == true
+end
+
 -- get the tool description from the tool kind
 function _instance:_description(toolkind)
     local descriptions = self._DESCRIPTIONS
@@ -708,8 +717,6 @@ function toolchain.load_fromfile(filepath, opt)
     local scope_opt = {interpreter = toolchain._interpreter(), deduplicate = true, enable_filter = true}
     local info = scopeinfo.new("toolchain", fileinfo.info, scope_opt)
     local instance = toolchain.load_withinfo(fileinfo.name, info, opt)
-    -- we need to skip check
-    instance._CHECKED = true
     return instance
 end
 
@@ -800,6 +807,7 @@ function toolchain.toolconfig(toolchains, name, opt)
     local toolconfig = cache:get2(cachekey, name)
     if toolconfig == nil then
         for _, toolchain_inst in ipairs(toolchains) do
+            assert(toolchain_inst:_is_checked())
             local values = toolchain_inst:get(name)
             if values then
                 toolconfig = toolconfig or {}