From f30908e4bb777840cac1fa4cf5eb3c8d7482bf53 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?=E4=BA=91=E6=B2=A7?= <1050706328@qq.com> Date: Mon, 16 Sep 2024 08:07:36 +0000 Subject: [PATCH] =?UTF-8?q?add=20=E9=94=99=E8=AF=AF=E8=B0=83=E7=94=A8?= =?UTF-8?q?=E5=AF=BC=E8=87=B4=E7=9A=84incompatible=20function=20pointer=20?= =?UTF-8?q?types=E9=97=AE=E9=A2=98.md.?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Signed-off-by: 云沧 <1050706328@qq.com> --- ... pointer types\351\227\256\351\242\230.md" | 240 ++++++++++++++++++ 1 file changed, 240 insertions(+) create mode 100644 "LLVM Parallel Universe Project/\351\227\256\351\242\230\345\256\232\344\275\215\346\200\273\347\273\223/\351\224\231\350\257\257\350\260\203\347\224\250\345\257\274\350\207\264\347\232\204incompatible function pointer types\351\227\256\351\242\230.md" diff --git "a/LLVM Parallel Universe Project/\351\227\256\351\242\230\345\256\232\344\275\215\346\200\273\347\273\223/\351\224\231\350\257\257\350\260\203\347\224\250\345\257\274\350\207\264\347\232\204incompatible function pointer types\351\227\256\351\242\230.md" "b/LLVM Parallel Universe Project/\351\227\256\351\242\230\345\256\232\344\275\215\346\200\273\347\273\223/\351\224\231\350\257\257\350\260\203\347\224\250\345\257\274\350\207\264\347\232\204incompatible function pointer types\351\227\256\351\242\230.md" new file mode 100644 index 0000000..6f7497b --- /dev/null +++ "b/LLVM Parallel Universe Project/\351\227\256\351\242\230\345\256\232\344\275\215\346\200\273\347\273\223/\351\224\231\350\257\257\350\260\203\347\224\250\345\257\274\350\207\264\347\232\204incompatible function pointer types\351\227\256\351\242\230.md" @@ -0,0 +1,240 @@ +# 1、问题现象 + +```c +[ 140s] test/regress.c:3707:2: error: incompatible function pointer types initializing 'testcase_fn' (aka 'void (*)(void *)') with an expression of type 'void (void)' [-Wincompatible-function-pointer-types] +[ 140s] 3707 | BASIC(event_config_set_max_dispatch_interval, TT_FORK|TT_NEED_BASE), +[ 140s] | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +[ 140s] test/regress.h:105:11: note: expanded from macro 'BASIC' +[ 140s] 105 | { #name, test_## name, flags, &basic_setup, NULL } +[ 140s] | ^~~~~~~~~~~~ +[ 140s] :168:1: note: expanded from here +[ 140s] 168 | test_event_config_set_max_dispatch_interval +[ 140s] | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +[ 140s] test/regress.c:3708:2: error: incompatible function pointer types initializing 'testcase_fn' (aka 'void (*)(void *)') with an expression of type 'void (void)' [-Wincompatible-function-pointer-types] +[ 140s] 3708 | BASIC(event_config_set_num_cpus_hint, TT_FORK|TT_NEED_BASE), +[ 140s] | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +[ 140s] test/regress.h:105:11: note: expanded from macro 'BASIC' +[ 140s] 105 | { #name, test_## name, flags, &basic_setup, NULL } +[ 140s] | ^~~~~~~~~~~~ +[ 140s] :170:1: note: expanded from here +[ 140s] 170 | test_event_config_set_num_cpus_hint +[ 140s] | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +[ 140s] 2 errors generated. +``` + +# 2、问题定位 + +## 2.1、问题定位分析 + +错误定位： + +```c +struct testcase_t main_testcases[] = { ++ /* event.c api tests */ ++ BASIC(event_base_del_virtual_, TT_FORK|TT_NEED_BASE), ++ BASIC(event_deferred_cb_set_priority_, TT_FORK|TT_NEED_BASE), ++ BASIC(event_callback_init_, TT_FORK|TT_NEED_BASE), ++ BASIC(event_del_noblock, TT_FORK|TT_NEED_BASE), ++ BASIC(event_del_block, TT_FORK|TT_NEED_BASE), ++ BASIC(event_get_events, TT_FORK|TT_NEED_BASE|TT_NEED_SOCKETPAIR), ++ BASIC(event_config_set_max_dispatch_interval, TT_FORK|TT_NEED_BASE), ++ BASIC(event_config_set_num_cpus_hint, TT_FORK|TT_NEED_BASE), ++ BASIC(event_base_stop_iocp_, TT_FORK|TT_NEED_BASE), +``` + +main_testcases[]的元素类型为struct testcase_t，而struct testcase_t的定义为： + +```c +/** A single test-case that you can run. */ +struct testcase_t { + const char *name; /**< An identifier for this case. */ + testcase_fn fn; /**< The function to run to implement this case. */ + unsigned long flags; /**< Bitfield of TT_* flags. */ + const struct testcase_setup_t *setup; /**< Optional setup/cleanup fns*/ + void *setup_data; /**< Extra data usable by setup function */ +}; +``` + +错误就出现在第二个元素testcase_fn fn，其类型定义为： + +```c +typedef void (*testcase_fn)(void *); +``` + +也就是说，要求类型为void\*(void\*) + +我们再来看看BASIC是什么，他是一个宏，定义如下，同时还需要注意，与他一同定义的LEGACY宏 + +```c +#define BASIC(name,flags) \ + { #name, test_## name, flags, &basic_setup, NULL } + +#define LEGACY(name,flags) \ + { #name, run_legacy_test_fn, flags|TT_LEGACY, &legacy_setup, \ + test_## name } +``` + +我们再回来看一开始报错的地方 + +```c ++ BASIC(event_config_set_max_dispatch_interval, TT_FORK|TT_NEED_BASE), ++ BASIC(event_config_set_num_cpus_hint, TT_FORK|TT_NEED_BASE), +``` + +也就是说，问题出在函数test_event_config_set_max_dispatch_interval和test_event_config_set_num_cpus_hint的类型不符合void\*(void\*)的要求，那我们来看看这两个函数的定义： + +```c ++static void ++test_event_config_set_max_dispatch_interval(void) ++{ ++ struct event_config *cfg = NULL; ++ struct timeval tv; ++ int max_dispatch_cbs = 100; ++ int min_priority = 2; ++ ++ evutil_timerclear(&tv); ++ tv.tv_sec = 3; ++ tv.tv_usec = 0; ++ ++ cfg = event_config_new(); ++ event_config_set_max_dispatch_interval(cfg, &tv, max_dispatch_cbs, min_priority); ++ ++ tt_assert(max_dispatch_cbs == cfg->max_dispatch_callbacks); ++ tt_assert(min_priority == cfg->limit_callbacks_after_prio); ++ tt_assert(3 == cfg->max_dispatch_interval.tv_sec); ++ tt_assert(0 == cfg->max_dispatch_interval.tv_usec); ++end: ++ if (cfg) ++ event_config_free(cfg); ++} ++ ++static void ++test_event_config_set_num_cpus_hint(void) ++{ ++ struct event_config *cfg = NULL; ++ int n_cpus = 4; ++ ++ cfg = event_config_new(); ++ event_config_set_num_cpus_hint(cfg, 4); ++ tt_assert(4 == cfg->n_cpus_hint); ++end: ++ if (cfg) ++ event_config_free(cfg); ++} +``` + +可见他们的类型是void(void) + +除了这两个函数之外，其他BASIC宏传入的函数（没有被报错的）的类型例如下： + +```c ++static void ++test_event_del_noblock(void *ptr) { ++ struct basic_test_data *data = ptr; ++ struct event_base *base = data->base; ++ struct timeval tv; ++ struct event ev; ++ int count = 0; ++ int res_del = 0; ++ ++ evutil_timerclear(&tv); ++ tv.tv_usec = 10000; ++ ++ event_assign(&ev, base, -1, EV_TIMEOUT|EV_PERSIST, ++ timeout_cb, &count); ++ event_add(&ev, &tv); ++ ++ res_del = event_del_noblock(&ev); ++ tt_int_op(res_del, ==, 0); ++end: ++ ; ++} ++ +``` + +修改方法显然不能直接改参数要求，如果将void改为void*，那么凭空要求传入一个参数，显然不对，那么还有其他方法吗？我在上游社区没有发现类似的issue，然而，我们可以去找找看，对于void(void)类型的函数，上游社区是如何将其传入testcase的，我们大致看一部分： + +```c +struct testcase_t main_testcases[] = { + /* Some converted-over tests */ + { "methods", test_methods, TT_FORK, NULL, NULL }, + { "version", test_version, 0, NULL, NULL }, + BASIC(base_features, TT_FORK|TT_NO_LOGS), + { "base_environ", test_base_environ, TT_FORK, NULL, NULL }, + + BASIC(event_base_new, TT_FORK|TT_NEED_SOCKETPAIR), + BASIC(free_active_base, TT_FORK|TT_NEED_SOCKETPAIR), + + BASIC(manipulate_active_events, TT_FORK|TT_NEED_BASE), + BASIC(event_new_selfarg, TT_FORK|TT_NEED_BASE), + BASIC(event_assign_selfarg, TT_FORK|TT_NEED_BASE), + BASIC(event_base_get_num_events, TT_FORK|TT_NEED_BASE), + BASIC(event_base_get_max_events, TT_FORK|TT_NEED_BASE), + BASIC(evmap_invalid_slots, TT_FORK|TT_NEED_BASE), + + BASIC(bad_assign, TT_FORK|TT_NEED_BASE|TT_NO_LOGS), + BASIC(bad_reentrant, TT_FORK|TT_NEED_BASE|TT_NO_LOGS), + BASIC(active_later, TT_FORK|TT_NEED_BASE|TT_NEED_SOCKETPAIR|TT_RETRIABLE), + BASIC(event_remove_timeout, TT_FORK|TT_NEED_BASE|TT_NEED_SOCKETPAIR), + + /* These are still using the old API */ + LEGACY(persistent_timeout, TT_FORK|TT_NEED_BASE), + { "persistent_timeout_jump", test_persistent_timeout_jump, TT_FORK|TT_NEED_BASE, &basic_setup, NULL }, + { "persistent_active_timeout", test_persistent_active_timeout, + TT_FORK|TT_NEED_BASE|TT_RETRIABLE, &basic_setup, NULL }, + LEGACY(priorities, TT_FORK|TT_NEED_BASE), + BASIC(priority_active_inversion, TT_FORK|TT_NEED_BASE), + { "common_timeout", test_common_timeout, TT_FORK|TT_NEED_BASE|TT_RETRIABLE, + &basic_setup, NULL }, + + /* These legacy tests may not all need all of these flags. */ + LEGACY(simpleread, TT_ISOLATED), + LEGACY(simpleread_multiple, TT_ISOLATED), + LEGACY(simplewrite, TT_ISOLATED), + { "simpleclose_rw", test_simpleclose_rw, TT_FORK, &basic_setup, NULL }, + /* simpleclose */ + { "simpleclose_close", test_simpleclose, + TT_FORK|TT_NEED_SOCKETPAIR|TT_NEED_BASE, + &basic_setup, (void *)"close" }, + { "simpleclose_shutdown", test_simpleclose, + TT_FORK|TT_NEED_SOCKETPAIR|TT_NEED_BASE, + &basic_setup, (void *)"shutdown" }, +``` + + +可见，除了BASIC，有时也用LEGACY，那么什么时候用BASIC，什么时候用LEGACY呢？本人查看了上文的所有testcase中的测试函数，发现BASIC用于传入void(void*)，而LEGACY用于传入void(void)，全部贴上来篇幅过长，因此此处只放一个例子： + +```c +LEGACY(persistent_timeout, TT_FORK|TT_NEED_BASE) +``` + +```c +static void +test_persistent_timeout(void) +{ + struct timeval tv; + struct event ev; + int count = 0; + + evutil_timerclear(&tv); + tv.tv_usec = 10000; + + event_assign(&ev, global_base, -1, EV_TIMEOUT|EV_PERSIST, + periodic_timeout_cb, &count); + event_add(&ev, &tv); + + event_dispatch(); + + event_del(&ev); +} +``` + +## 2.2、问题总结及根因确认 + +[add-testcases-for-event.c-apis.patch](https://gitee.com/src-openeuler/libevent/blob/6fd712438bafd9eafdb3cf3b3e9d66913378b2a3/add-testcases-for-event.c-apis.patch)该patch试图增加对一些函数的testcase，对于void(void)类型的函数，正确的方法是调用LEGACY宏将函数加入测试行列，错误在于调用了BASIC宏（其用于void(void*)类型的函数） + +# 3、修改建议 + +把报错两处的BASIC改为LEGACY， + +参考：[Fix function undeclared,incompatible pointer and parameter lack in 'add-testcases-for-event.c-apis.patch',support clang build · Pull Request !74 · src-openEuler/libevent - Gitee.com](https://gitee.com/src-openeuler/libevent/pulls/74) \ No newline at end of file -- Gitee