svn commit: r311651 - in head/lib/libc: include stdlib
Konstantin Belousov
kib at FreeBSD.org
Sat Jan 7 16:05:20 UTC 2017
Author: kib
Date: Sat Jan 7 16:05:19 2017
New Revision: 311651
URL: https://svnweb.freebsd.org/changeset/base/311651
Log:
Export __cxa_thread_atexit_impl as an alias for __cxa_thread_atexit.
libstdc++ before gcc r244057 expected that libc provided
__cxa_thread_atexit_impl, and libstdc++ implemented
__cxa_thread_atexit, by forwarding the calls to _impl. Mentioned gcc
revision checks for __cxa_thread_atexit in libc and does not provide
the symbol from libstdc++ if found.
This change helps older gcc, in particular, all released versions
which implement thread_local, by consolidating the implementation into
libc. For that versions, if configured with the current libc, the
__cxa_thread_atexit is exported from libstdc++ as a trivial wrapper
around libc::__cxa_thread_atexit_impl.
The __cxa_thread_atexit implementation is put into separate source
file to allow for static linking with older libstdc++.a.
gcc bugzilla: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78968
Reported by: Hannes Hauswedell <h2+fbsdports at fsfe.org>
PR: 215709
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Added:
head/lib/libc/stdlib/cxa_thread_atexit_impl.c
- copied, changed from r311650, head/lib/libc/stdlib/cxa_thread_atexit.c
Modified:
head/lib/libc/include/libc_private.h
head/lib/libc/stdlib/Makefile.inc
head/lib/libc/stdlib/Symbol.map
head/lib/libc/stdlib/cxa_thread_atexit.c
Modified: head/lib/libc/include/libc_private.h
==============================================================================
--- head/lib/libc/include/libc_private.h Sat Jan 7 15:58:57 2017 (r311650)
+++ head/lib/libc/include/libc_private.h Sat Jan 7 16:05:19 2017 (r311651)
@@ -272,6 +272,8 @@ void _malloc_thread_cleanup(void);
* thread is exiting, so its thread-local dtors should be called.
*/
void __cxa_thread_call_dtors(void);
+int __cxa_thread_atexit_hidden(void (*dtor_func)(void *), void *obj,
+ void *dso_symbol) __hidden;
/*
* These functions are used by the threading libraries in order to protect
Modified: head/lib/libc/stdlib/Makefile.inc
==============================================================================
--- head/lib/libc/stdlib/Makefile.inc Sat Jan 7 15:58:57 2017 (r311650)
+++ head/lib/libc/stdlib/Makefile.inc Sat Jan 7 16:05:19 2017 (r311651)
@@ -5,7 +5,9 @@
.PATH: ${LIBC_SRCTOP}/${LIBC_ARCH}/stdlib ${LIBC_SRCTOP}/stdlib
MISRCS+=C99_Exit.c a64l.c abort.c abs.c atexit.c atof.c atoi.c atol.c atoll.c \
- bsearch.c cxa_thread_atexit.c div.c exit.c getenv.c getopt.c getopt_long.c \
+ bsearch.c \
+ cxa_thread_atexit.c cxa_thread_atexit_impl.c \
+ div.c exit.c getenv.c getopt.c getopt_long.c \
getsubopt.c hcreate.c hcreate_r.c hdestroy_r.c heapsort.c heapsort_b.c \
hsearch_r.c imaxabs.c imaxdiv.c \
insque.c l64a.c labs.c ldiv.c llabs.c lldiv.c lsearch.c \
Modified: head/lib/libc/stdlib/Symbol.map
==============================================================================
--- head/lib/libc/stdlib/Symbol.map Sat Jan 7 15:58:57 2017 (r311650)
+++ head/lib/libc/stdlib/Symbol.map Sat Jan 7 16:05:19 2017 (r311651)
@@ -118,6 +118,7 @@ FBSD_1.4 {
FBSD_1.5 {
__cxa_thread_atexit;
+ __cxa_thread_atexit_impl;
};
FBSDprivate_1.0 {
Modified: head/lib/libc/stdlib/cxa_thread_atexit.c
==============================================================================
--- head/lib/libc/stdlib/cxa_thread_atexit.c Sat Jan 7 15:58:57 2017 (r311650)
+++ head/lib/libc/stdlib/cxa_thread_atexit.c Sat Jan 7 16:05:19 2017 (r311651)
@@ -1,7 +1,10 @@
/*-
- * Copyright (c) 2016 Mahdi Mokhtari <mokhi64 at gmail.com>
+ * Copyright (c) 2017 The FreeBSD Foundation
* All rights reserved.
*
+ * Portions of this software were developed by Konstantin Belousov
+ * under sponsorship from the FreeBSD Foundation.
+ *
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
@@ -27,114 +30,11 @@
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
-#include <sys/queue.h>
-#include "namespace.h"
-#include <errno.h>
-#include <link.h>
-#include <pthread.h>
-#include <stddef.h>
-#include <stdlib.h>
-#include <stdio.h>
-#include "un-namespace.h"
#include "libc_private.h"
-/*
- * C++11 introduces the thread_local scope (like __thread with some
- * additions). As a key-feature it should support non-trivial
- * destructors, registered with __cxa_thread_atexit() to be executed
- * at the thread termination.
- *
- * The implemention keeps a _Thread_local list of destructors per each
- * thread, and calls __cxa_thread_call_dtors() on each thread's exit
- * to do cleanup. For a thread calling exit(3), in particular, for
- * the initial thread returning from main(), we call
- * __cxa_thread_call_dtors() inside exit().
- *
- * It could be possible that a dynamically loaded library, use
- * thread_local variable but is dlclose()'d before thread exit. The
- * destructor of this variable will then try to access the address,
- * for calling it but it's unloaded, so it'll crash. We're using
- * __elf_phdr_match_addr() to detect and prevent such cases and so
- * prevent the crash.
- */
-
-#define CXA_DTORS_ITERATIONS 4
-
-struct cxa_thread_dtor {
- void *obj;
- void (*func)(void *);
- void *dso;
- LIST_ENTRY(cxa_thread_dtor) entry;
-};
-static _Thread_local LIST_HEAD(dtor_list, cxa_thread_dtor) dtors =
- LIST_HEAD_INITIALIZER(dtors);
-
int
__cxa_thread_atexit(void (*dtor_func)(void *), void *obj, void *dso_symbol)
{
- struct cxa_thread_dtor *new_dtor;
-
- new_dtor = malloc(sizeof(*new_dtor));
- if (new_dtor == NULL) {
- errno = ENOMEM; /* forcibly override malloc(3) error */
- return (-1);
- }
-
- new_dtor->obj = obj;
- new_dtor->func = dtor_func;
- new_dtor->dso = dso_symbol;
- LIST_INSERT_HEAD(&dtors, new_dtor, entry);
- return (0);
-}
-
-static void
-walk_cb_call(struct cxa_thread_dtor *dtor)
-{
- struct dl_phdr_info phdr_info;
-
- if (_rtld_addr_phdr(dtor->dso, &phdr_info) &&
- __elf_phdr_match_addr(&phdr_info, dtor->func))
- dtor->func(dtor->obj);
- else
- fprintf(stderr, "__cxa_thread_call_dtors: dtr %p from "
- "unloaded dso, skipping\n", (void *)(dtor->func));
-}
-
-static void
-walk_cb_nocall(struct cxa_thread_dtor *dtor __unused)
-{
-}
-
-static void
-cxa_thread_walk(void (*cb)(struct cxa_thread_dtor *))
-{
- struct cxa_thread_dtor *dtor, *tdtor;
-
- LIST_FOREACH_SAFE(dtor, &dtors, entry, tdtor) {
- LIST_REMOVE(dtor, entry);
- cb(dtor);
- free(dtor);
- }
-}
-
-/*
- * This is the callback function we use to call destructors, once for
- * each thread. It is called in exit(3) in libc/stdlib/exit.c and
- * before exit_thread() in libthr/thread/thr_exit.c.
- */
-void
-__cxa_thread_call_dtors(void)
-{
- int i;
-
- for (i = 0; i < CXA_DTORS_ITERATIONS && !LIST_EMPTY(&dtors); i++)
- cxa_thread_walk(walk_cb_call);
- if (!LIST_EMPTY(&dtors)) {
- fprintf(stderr, "Thread %p is exiting with more "
- "thread-specific dtors created after %d iterations "
- "of destructor calls\n",
- _pthread_self(), i);
- cxa_thread_walk(walk_cb_nocall);
- }
+ return (__cxa_thread_atexit_hidden(dtor_func, obj, dso_symbol));
}
Copied and modified: head/lib/libc/stdlib/cxa_thread_atexit_impl.c (from r311650, head/lib/libc/stdlib/cxa_thread_atexit.c)
==============================================================================
--- head/lib/libc/stdlib/cxa_thread_atexit.c Sat Jan 7 15:58:57 2017 (r311650, copy source)
+++ head/lib/libc/stdlib/cxa_thread_atexit_impl.c Sat Jan 7 16:05:19 2017 (r311651)
@@ -1,7 +1,11 @@
/*-
* Copyright (c) 2016 Mahdi Mokhtari <mokhi64 at gmail.com>
+ * Copyright (c) 2016, 2017 The FreeBSD Foundation
* All rights reserved.
*
+ * Portions of this software were developed by Konstantin Belousov
+ * under sponsorship from the FreeBSD Foundation.
+ *
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
@@ -70,7 +74,16 @@ static _Thread_local LIST_HEAD(dtor_list
LIST_HEAD_INITIALIZER(dtors);
int
-__cxa_thread_atexit(void (*dtor_func)(void *), void *obj, void *dso_symbol)
+__cxa_thread_atexit_impl(void (*dtor_func)(void *), void *obj,
+ void *dso_symbol)
+{
+
+ return (__cxa_thread_atexit_hidden(dtor_func, obj, dso_symbol));
+}
+
+int
+__cxa_thread_atexit_hidden(void (*dtor_func)(void *), void *obj,
+ void *dso_symbol)
{
struct cxa_thread_dtor *new_dtor;
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