add code to support stack unwinding when thread exits. note that only
defer-mode cancellation works, asynchrnous mode does not work because it lacks of libuwind's support. stack unwinding is not enabled unless LIBTHR_UNWIND_STACK is defined in Makefile.
This commit is contained in:
parent
707ee8154d
commit
3832fd24f1
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=212630
@ -25,6 +25,14 @@ CFLAGS+=-I${.CURDIR}/../../libexec/rtld-elf
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CFLAGS+=-I${.CURDIR}/../../libexec/rtld-elf/${MACHINE_CPUARCH}
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CFLAGS+=-I${.CURDIR}/../libthread_db
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CFLAGS+=-Winline
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LIBTHR_UNWIND_STACK=yes
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.ifdef LIBTHR_UNWIND_STACK
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CFLAGS+=-I${.CURDIR}/../../contrib/gcc -fexceptions
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CFLAGS+=-D_PTHREAD_FORCED_UNWIND
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.endif
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LDFLAGS+=-Wl,-znodelete
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VERSION_DEF=${.CURDIR}/../libc/Versions.def
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@ -78,6 +78,9 @@ __pthread_cleanup_pop_imp(int execute)
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void
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_pthread_cleanup_push(void (*routine) (void *), void *arg)
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{
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#ifdef _PTHREAD_FORCED_UNWIND
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PANIC("_pthread_cleanup_push is not supported while stack unwinding is enabled.");
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#else
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struct pthread *curthread = _get_curthread();
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struct pthread_cleanup *newbuf;
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@ -89,10 +92,15 @@ _pthread_cleanup_push(void (*routine) (void *), void *arg)
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newbuf->prev = curthread->cleanup;
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curthread->cleanup = newbuf;
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}
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#endif
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}
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void
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_pthread_cleanup_pop(int execute)
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{
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#ifdef _PTHREAD_FORCED_UNWIND
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PANIC("_pthread_cleanup_pop is not supported while stack unwinding is enabled.");
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#else
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__pthread_cleanup_pop_imp(execute);
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#endif
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}
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@ -264,6 +264,11 @@ thread_start(struct pthread *curthread)
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__sys_sigprocmask(SIG_SETMASK, &set, NULL);
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}
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#ifdef _PTHREAD_FORCED_UNWIND
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curthread->unwind_stackend = (char *)curthread->attr.stackaddr_attr +
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curthread->attr.stacksize_attr;
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#endif
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/* Run the current thread's start routine with argument: */
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_pthread_exit(curthread->start_routine(curthread->arg));
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@ -31,6 +31,9 @@
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#include "namespace.h"
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#include <errno.h>
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#ifdef _PTHREAD_FORCED_UNWIND
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#include <dlfcn.h>
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#endif
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#include <stdio.h>
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#include <stdlib.h>
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#include <pthread.h>
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@ -43,8 +46,125 @@
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void _pthread_exit(void *status);
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static void exit_thread(void) __dead2;
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__weak_reference(_pthread_exit, pthread_exit);
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#ifdef _PTHREAD_FORCED_UNWIND
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static void thread_unwind(void) __dead2;
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#ifdef PIC
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static void thread_uw_init(void);
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static _Unwind_Reason_Code thread_unwind_stop(int version,
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_Unwind_Action actions,
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_Unwind_Exception_Class exc_class,
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struct _Unwind_Exception *exc_obj,
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struct _Unwind_Context *context, void *stop_parameter);
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/* unwind library pointers */
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static _Unwind_Reason_Code (*uwl_forcedunwind)(struct _Unwind_Exception *,
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_Unwind_Stop_Fn, void *);
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static void (*uwl_resume)(struct _Unwind_Exception *exc);
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static _Unwind_Word (*uwl_getcfa)(struct _Unwind_Context *);
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static void
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thread_uw_init(void)
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{
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static int inited = 0;
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void *handle;
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if (inited)
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return;
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inited = 1;
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handle = RTLD_DEFAULT;
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if ((uwl_forcedunwind = dlsym(handle, "_Unwind_ForcedUnwind")) == NULL||
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(uwl_resume = dlsym(handle, "_Unwind_Resume")) == NULL ||
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(uwl_getcfa = dlsym(handle, "_Unwind_GetCFA")) == NULL) {
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uwl_forcedunwind = NULL;
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return;
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}
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}
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void
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_Unwind_Resume(struct _Unwind_Exception *ex)
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{
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(*uwl_resume)(ex);
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}
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_Unwind_Reason_Code
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_Unwind_ForcedUnwind(struct _Unwind_Exception *ex, _Unwind_Stop_Fn stop_func,
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void *stop_arg)
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{
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return (*uwl_forcedunwind)(ex, stop_func, stop_arg);
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}
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_Unwind_Word
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_Unwind_GetCFA(struct _Unwind_Context *context)
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{
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return (*uwl_getcfa)(context);
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}
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#else
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#pragma weak _Unwind_GetCFA
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#pragma weak _Unwind_ForcedUnwind
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#pragma weak _Unwind_Resume
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#endif /* PIC */
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static void
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thread_unwind_cleanup(_Unwind_Reason_Code code, struct _Unwind_Exception *e)
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{
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/*
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* Specification said that _Unwind_Resume should not be used here,
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* instead, user should rethrow the exception. For C++ user, they
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* should put "throw" sentence in catch(...) block.
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*/
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PANIC("exception should be rethrown");
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}
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static _Unwind_Reason_Code
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thread_unwind_stop(int version, _Unwind_Action actions,
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_Unwind_Exception_Class exc_class,
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struct _Unwind_Exception *exc_obj,
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struct _Unwind_Context *context, void *stop_parameter)
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{
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struct pthread *curthread = _get_curthread();
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struct pthread_cleanup *cur;
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uintptr_t cfa;
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int done = 0;
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/* XXX assume stack grows down to lower address */
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cfa = _Unwind_GetCFA(context);
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if (actions & _UA_END_OF_STACK) {
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done = 1;
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} else if (cfa >= (uintptr_t)curthread->unwind_stackend) {
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done = 1;
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}
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while ((cur = curthread->cleanup) != NULL &&
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(done ||
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((uintptr_t)cur < (uintptr_t)curthread->unwind_stackend &&
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(uintptr_t)cur >= cfa))) {
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__pthread_cleanup_pop_imp(1);
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}
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if (done)
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exit_thread(); /* Never return! */
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return (_URC_NO_REASON);
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}
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static void
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thread_unwind(void)
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{
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struct pthread *curthread = _get_curthread();
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curthread->ex.exception_class = 0;
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curthread->ex.exception_cleanup = thread_unwind_cleanup;
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_Unwind_ForcedUnwind(&curthread->ex, thread_unwind_stop, NULL);
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PANIC("_Unwind_ForcedUnwind returned");
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}
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#endif
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void
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_thread_exit(const char *fname, int lineno, const char *msg)
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{
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@ -95,9 +215,38 @@ _pthread_exit_mask(void *status, sigset_t *mask)
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/* Save the return value: */
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curthread->ret = status;
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while (curthread->cleanup != NULL) {
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_pthread_cleanup_pop(1);
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#ifdef _PTHREAD_FORCED_UNWIND
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#ifdef PIC
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thread_uw_init();
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if (uwl_forcedunwind != NULL) {
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thread_unwind();
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}
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#else
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if (_Unwind_ForcedUnwind != NULL) {
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thread_unwind();
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}
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#endif /* PIC */
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else {
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while (curthread->cleanup != NULL) {
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__pthread_cleanup_pop_imp(1);
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}
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exit_thread();
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}
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#else
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while (curthread->cleanup != NULL) {
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__pthread_cleanup_pop_imp(1);
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}
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exit_thread();
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#endif /* _PTHREAD_FORCED_UNWIND */
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}
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static void
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exit_thread(void)
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{
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struct pthread *curthread = _get_curthread();
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/* Check if there is thread specific data: */
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if (curthread->specific != NULL) {
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@ -413,6 +413,10 @@ init_main_thread(struct pthread *thread)
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&sched_param);
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thread->attr.prio = sched_param.sched_priority;
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#ifdef _PTHREAD_FORCED_UNWIND
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thread->unwind_stackend = _usrstack;
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#endif
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/* Others cleared to zero by thr_alloc() */
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}
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#include "thr_umtx.h"
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#include "thread_db.h"
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#ifdef _PTHREAD_FORCED_UNWIND
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#include <unwind-generic.h>
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#endif
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typedef TAILQ_HEAD(pthreadlist, pthread) pthreadlist;
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typedef TAILQ_HEAD(atfork_head, pthread_atfork) atfork_head;
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TAILQ_HEAD(mutex_queue, pthread_mutex);
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@ -446,6 +450,11 @@ struct pthread {
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/* Cleanup handlers Link List */
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struct pthread_cleanup *cleanup;
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#ifdef _PTHREAD_FORCED_UNWIND
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struct _Unwind_Exception ex;
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void *unwind_stackend;
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#endif
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/*
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* Magic value to help recognize a valid thread structure
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* from an invalid one:
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