From 554fd8c5195424bdbcabf5de30fdc183aba391bd Mon Sep 17 00:00:00 2001 From: upstream source tree Date: Sun, 15 Mar 2015 20:14:05 -0400 Subject: obtained gcc-4.6.4.tar.bz2 from upstream website; verified gcc-4.6.4.tar.bz2.sig; imported gcc-4.6.4 source tree from verified upstream tarball. downloading a git-generated archive based on the 'upstream' tag should provide you with a source tree that is binary identical to the one extracted from the above tarball. if you have obtained the source via the command 'git clone', however, do note that line-endings of files in your working directory might differ from line-endings of the respective files in the upstream repository. --- libjava/posix-threads.cc | 732 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 732 insertions(+) create mode 100644 libjava/posix-threads.cc (limited to 'libjava/posix-threads.cc') diff --git a/libjava/posix-threads.cc b/libjava/posix-threads.cc new file mode 100644 index 000000000..66693abbc --- /dev/null +++ b/libjava/posix-threads.cc @@ -0,0 +1,732 @@ +// posix-threads.cc - interface between libjava and POSIX threads. + +/* Copyright (C) 1998, 1999, 2000, 2001, 2004, 2006 Free Software Foundation + + This file is part of libgcj. + +This software is copyrighted work licensed under the terms of the +Libgcj License. Please consult the file "LIBGCJ_LICENSE" for +details. */ + +// TO DO: +// * Document signal handling limitations + +#include + +#include "posix.h" +#include "posix-threads.h" + +// If we're using the Boehm GC, then we need to override some of the +// thread primitives. This is fairly gross. +#ifdef HAVE_BOEHM_GC +#include +#endif /* HAVE_BOEHM_GC */ + +#include +#include +#include +#include +#include +#ifdef HAVE_UNISTD_H +#include // To test for _POSIX_THREAD_PRIORITY_SCHEDULING +#endif + +#include +#include +#include +#include +#include +#include +#include + +// This is used to implement thread startup. +struct starter +{ + _Jv_ThreadStartFunc *method; + _Jv_Thread_t *data; +}; + +// This is the key used to map from the POSIX thread value back to the +// Java object representing the thread. The key is global to all +// threads, so it is ok to make it a global here. +pthread_key_t _Jv_ThreadKey; + +// This is the key used to map from the POSIX thread value back to the +// _Jv_Thread_t* representing the thread. +pthread_key_t _Jv_ThreadDataKey; + +// We keep a count of all non-daemon threads which are running. When +// this reaches zero, _Jv_ThreadWait returns. +static pthread_mutex_t daemon_mutex; +static pthread_cond_t daemon_cond; +static int non_daemon_count; + +// The signal to use when interrupting a thread. +#if defined(LINUX_THREADS) || defined(FREEBSD_THREADS) + // LinuxThreads (prior to glibc 2.1) usurps both SIGUSR1 and SIGUSR2. + // GC on FreeBSD uses both SIGUSR1 and SIGUSR2. +# define INTR SIGHUP +#else /* LINUX_THREADS */ +# define INTR SIGUSR2 +#endif /* LINUX_THREADS */ + +// +// These are the flags that can appear in _Jv_Thread_t. +// + +// Thread started. +#define FLAG_START 0x01 +// Thread is daemon. +#define FLAG_DAEMON 0x02 + + + +int +_Jv_MutexLock (_Jv_Mutex_t *mu) +{ + pthread_t self = pthread_self (); + if (mu->owner == self) + { + mu->count++; + } + else + { + JvSetThreadState holder (_Jv_ThreadCurrent(), JV_BLOCKED); + +# ifdef LOCK_DEBUG + int result = pthread_mutex_lock (&mu->mutex); + if (0 != result) + { + fprintf(stderr, "Pthread_mutex_lock returned %d\n", result); + for (;;) {} + } +# else + pthread_mutex_lock (&mu->mutex); +# endif + mu->count = 1; + mu->owner = self; + } + return 0; +} + +// Wait for the condition variable "CV" to be notified. +// Return values: +// 0: the condition was notified, or the timeout expired. +// _JV_NOT_OWNER: the thread does not own the mutex "MU". +// _JV_INTERRUPTED: the thread was interrupted. Its interrupted flag is set. +int +_Jv_CondWait (_Jv_ConditionVariable_t *cv, _Jv_Mutex_t *mu, + jlong millis, jint nanos) +{ + pthread_t self = pthread_self(); + if (mu->owner != self) + return _JV_NOT_OWNER; + + struct timespec ts; + + JvThreadState new_state = JV_WAITING; + if (millis > 0 || nanos > 0) + { + // Calculate the abstime corresponding to the timeout. + unsigned long long seconds; + unsigned long usec; + + // For better accuracy, should use pthread_condattr_setclock + // and clock_gettime. +#ifdef HAVE_GETTIMEOFDAY + timeval tv; + gettimeofday (&tv, NULL); + usec = tv.tv_usec; + seconds = tv.tv_sec; +#else + unsigned long long startTime = java::lang::System::currentTimeMillis(); + seconds = startTime / 1000; + /* Assume we're about half-way through this millisecond. */ + usec = (startTime % 1000) * 1000 + 500; +#endif + /* These next two statements cannot overflow. */ + usec += nanos / 1000; + usec += (millis % 1000) * 1000; + /* These two statements could overflow only if tv.tv_sec was + insanely large. */ + seconds += millis / 1000; + seconds += usec / 1000000; + + ts.tv_sec = seconds; + if (ts.tv_sec < 0 || (unsigned long long)ts.tv_sec != seconds) + { + // We treat a timeout that won't fit into a struct timespec + // as a wait forever. + millis = nanos = 0; + } + else + /* This next statement also cannot overflow. */ + ts.tv_nsec = (usec % 1000000) * 1000 + (nanos % 1000); + } + + _Jv_Thread_t *current = _Jv_ThreadCurrentData (); + java::lang::Thread *current_obj = _Jv_ThreadCurrent (); + + pthread_mutex_lock (¤t->wait_mutex); + + // Now that we hold the wait mutex, check if this thread has been + // interrupted already. + if (current_obj->interrupt_flag) + { + pthread_mutex_unlock (¤t->wait_mutex); + return _JV_INTERRUPTED; + } + + // Set the thread's state. + JvSetThreadState holder (current_obj, new_state); + + // Add this thread to the cv's wait set. + current->next = NULL; + + if (cv->first == NULL) + cv->first = current; + else + for (_Jv_Thread_t *t = cv->first;; t = t->next) + { + if (t->next == NULL) + { + t->next = current; + break; + } + } + + // Record the current lock depth, so it can be restored when we re-aquire it. + int count = mu->count; + + // Release the monitor mutex. + mu->count = 0; + mu->owner = 0; + pthread_mutex_unlock (&mu->mutex); + + int r = 0; + bool done_sleeping = false; + + while (! done_sleeping) + { + if (millis == 0 && nanos == 0) + r = pthread_cond_wait (¤t->wait_cond, ¤t->wait_mutex); + else + r = pthread_cond_timedwait (¤t->wait_cond, ¤t->wait_mutex, + &ts); + + // In older glibc's (prior to 2.1.3), the cond_wait functions may + // spuriously wake up on a signal. Catch that here. + if (r != EINTR) + done_sleeping = true; + } + + // Check for an interrupt *before* releasing the wait mutex. + jboolean interrupted = current_obj->interrupt_flag; + + pthread_mutex_unlock (¤t->wait_mutex); + + // Reaquire the monitor mutex, and restore the lock count. + pthread_mutex_lock (&mu->mutex); + mu->owner = self; + mu->count = count; + + // If we were interrupted, or if a timeout occurred, remove ourself from + // the cv wait list now. (If we were notified normally, notify() will have + // already taken care of this) + if (r == ETIMEDOUT || interrupted) + { + _Jv_Thread_t *prev = NULL; + for (_Jv_Thread_t *t = cv->first; t != NULL; t = t->next) + { + if (t == current) + { + if (prev != NULL) + prev->next = t->next; + else + cv->first = t->next; + t->next = NULL; + break; + } + prev = t; + } + if (interrupted) + return _JV_INTERRUPTED; + } + + return 0; +} + +int +_Jv_CondNotify (_Jv_ConditionVariable_t *cv, _Jv_Mutex_t *mu) +{ + if (_Jv_MutexCheckMonitor (mu)) + return _JV_NOT_OWNER; + + _Jv_Thread_t *target; + _Jv_Thread_t *prev = NULL; + + for (target = cv->first; target != NULL; target = target->next) + { + pthread_mutex_lock (&target->wait_mutex); + + if (target->thread_obj->interrupt_flag) + { + // Don't notify a thread that has already been interrupted. + pthread_mutex_unlock (&target->wait_mutex); + prev = target; + continue; + } + + pthread_cond_signal (&target->wait_cond); + pthread_mutex_unlock (&target->wait_mutex); + + // Two concurrent notify() calls must not be delivered to the same + // thread, so remove the target thread from the cv wait list now. + if (prev == NULL) + cv->first = target->next; + else + prev->next = target->next; + + target->next = NULL; + + break; + } + + return 0; +} + +int +_Jv_CondNotifyAll (_Jv_ConditionVariable_t *cv, _Jv_Mutex_t *mu) +{ + if (_Jv_MutexCheckMonitor (mu)) + return _JV_NOT_OWNER; + + _Jv_Thread_t *target; + _Jv_Thread_t *prev = NULL; + + for (target = cv->first; target != NULL; target = target->next) + { + pthread_mutex_lock (&target->wait_mutex); + pthread_cond_signal (&target->wait_cond); + pthread_mutex_unlock (&target->wait_mutex); + + if (prev != NULL) + prev->next = NULL; + prev = target; + } + if (prev != NULL) + prev->next = NULL; + + cv->first = NULL; + + return 0; +} + +void +_Jv_ThreadInterrupt (_Jv_Thread_t *data) +{ + pthread_mutex_lock (&data->wait_mutex); + + // Set the thread's interrupted flag *after* aquiring its wait_mutex. This + // ensures that there are no races with the interrupt flag being set after + // the waiting thread checks it and before pthread_cond_wait is entered. + data->thread_obj->interrupt_flag = true; + + // Interrupt blocking system calls using a signal. + pthread_kill (data->thread, INTR); + + pthread_cond_signal (&data->wait_cond); + + pthread_mutex_unlock (&data->wait_mutex); +} + +/** + * Releases the block on a thread created by _Jv_ThreadPark(). This + * method can also be used to terminate a blockage caused by a prior + * call to park. This operation is unsafe, as the thread must be + * guaranteed to be live. + * + * @param thread the thread to unblock. + */ +void +ParkHelper::unpark () +{ + using namespace ::java::lang; + volatile obj_addr_t *ptr = &permit; + + /* If this thread is in state RUNNING, give it a permit and return + immediately. */ + if (compare_and_swap + (ptr, Thread::THREAD_PARK_RUNNING, Thread::THREAD_PARK_PERMIT)) + return; + + /* If this thread is parked, put it into state RUNNING and send it a + signal. */ + if (compare_and_swap + (ptr, Thread::THREAD_PARK_PARKED, Thread::THREAD_PARK_RUNNING)) + { + int result; + pthread_mutex_lock (&mutex); + result = pthread_cond_signal (&cond); + pthread_mutex_unlock (&mutex); + JvAssert (result == 0); + } +} + +/** + * Sets our state to dead. + */ +void +ParkHelper::deactivate () +{ + permit = ::java::lang::Thread::THREAD_PARK_DEAD; +} + +void +ParkHelper::init () +{ + pthread_mutex_init (&mutex, NULL); + pthread_cond_init (&cond, NULL); + permit = ::java::lang::Thread::THREAD_PARK_RUNNING; +} + +/** + * Blocks the thread until a matching _Jv_ThreadUnpark() occurs, the + * thread is interrupted or the optional timeout expires. If an + * unpark call has already occurred, this also counts. A timeout + * value of zero is defined as no timeout. When isAbsolute is true, + * the timeout is in milliseconds relative to the epoch. Otherwise, + * the value is the number of nanoseconds which must occur before + * timeout. This call may also return spuriously (i.e. for no + * apparent reason). + * + * @param isAbsolute true if the timeout is specified in milliseconds from + * the epoch. + * @param time either the number of nanoseconds to wait, or a time in + * milliseconds from the epoch to wait for. + */ +void +ParkHelper::park (jboolean isAbsolute, jlong time) +{ + using namespace ::java::lang; + volatile obj_addr_t *ptr = &permit; + + /* If we have a permit, return immediately. */ + if (compare_and_swap + (ptr, Thread::THREAD_PARK_PERMIT, Thread::THREAD_PARK_RUNNING)) + return; + + struct timespec ts; + + if (time) + { + unsigned long long seconds; + unsigned long usec; + + if (isAbsolute) + { + ts.tv_sec = time / 1000; + ts.tv_nsec = (time % 1000) * 1000 * 1000; + } + else + { + // Calculate the abstime corresponding to the timeout. + jlong nanos = time; + jlong millis = 0; + + // For better accuracy, should use pthread_condattr_setclock + // and clock_gettime. +#ifdef HAVE_GETTIMEOFDAY + timeval tv; + gettimeofday (&tv, NULL); + usec = tv.tv_usec; + seconds = tv.tv_sec; +#else + unsigned long long startTime + = java::lang::System::currentTimeMillis(); + seconds = startTime / 1000; + /* Assume we're about half-way through this millisecond. */ + usec = (startTime % 1000) * 1000 + 500; +#endif + /* These next two statements cannot overflow. */ + usec += nanos / 1000; + usec += (millis % 1000) * 1000; + /* These two statements could overflow only if tv.tv_sec was + insanely large. */ + seconds += millis / 1000; + seconds += usec / 1000000; + + ts.tv_sec = seconds; + if (ts.tv_sec < 0 || (unsigned long long)ts.tv_sec != seconds) + { + // We treat a timeout that won't fit into a struct timespec + // as a wait forever. + millis = nanos = 0; + } + else + /* This next statement also cannot overflow. */ + ts.tv_nsec = (usec % 1000000) * 1000 + (nanos % 1000); + } + } + + pthread_mutex_lock (&mutex); + if (compare_and_swap + (ptr, Thread::THREAD_PARK_RUNNING, Thread::THREAD_PARK_PARKED)) + { + int result = 0; + + if (! time) + result = pthread_cond_wait (&cond, &mutex); + else + result = pthread_cond_timedwait (&cond, &mutex, &ts); + + JvAssert (result == 0 || result == ETIMEDOUT); + + /* If we were unparked by some other thread, this will already + be in state THREAD_PARK_RUNNING. If we timed out or were + interrupted, we have to do it ourself. */ + permit = Thread::THREAD_PARK_RUNNING; + } + pthread_mutex_unlock (&mutex); +} + +static void +handle_intr (int) +{ + // Do nothing. +} + +void +_Jv_BlockSigchld() +{ + sigset_t mask; + sigemptyset (&mask); + sigaddset (&mask, SIGCHLD); + int c = pthread_sigmask (SIG_BLOCK, &mask, NULL); + if (c != 0) + JvFail (strerror (c)); +} + +void +_Jv_UnBlockSigchld() +{ + sigset_t mask; + sigemptyset (&mask); + sigaddset (&mask, SIGCHLD); + int c = pthread_sigmask (SIG_UNBLOCK, &mask, NULL); + if (c != 0) + JvFail (strerror (c)); +} + +void +_Jv_InitThreads (void) +{ + pthread_key_create (&_Jv_ThreadKey, NULL); + pthread_key_create (&_Jv_ThreadDataKey, NULL); + pthread_mutex_init (&daemon_mutex, NULL); + pthread_cond_init (&daemon_cond, 0); + non_daemon_count = 0; + + // Arrange for the interrupt signal to interrupt system calls. + struct sigaction act; + act.sa_handler = handle_intr; + sigemptyset (&act.sa_mask); + act.sa_flags = 0; + sigaction (INTR, &act, NULL); + + // Block SIGCHLD here to ensure that any non-Java threads inherit the new + // signal mask. + _Jv_BlockSigchld(); + + // Check/set the thread stack size. + size_t min_ss = 32 * 1024; + + if (sizeof (void *) == 8) + // Bigger default on 64-bit systems. + min_ss *= 2; + +#ifdef PTHREAD_STACK_MIN + if (min_ss < PTHREAD_STACK_MIN) + min_ss = PTHREAD_STACK_MIN; +#endif + + if (gcj::stack_size > 0 && gcj::stack_size < min_ss) + gcj::stack_size = min_ss; +} + +_Jv_Thread_t * +_Jv_ThreadInitData (java::lang::Thread *obj) +{ + _Jv_Thread_t *data = (_Jv_Thread_t *) _Jv_Malloc (sizeof (_Jv_Thread_t)); + data->flags = 0; + data->thread_obj = obj; + + pthread_mutex_init (&data->wait_mutex, NULL); + pthread_cond_init (&data->wait_cond, NULL); + + return data; +} + +void +_Jv_ThreadDestroyData (_Jv_Thread_t *data) +{ + pthread_mutex_destroy (&data->wait_mutex); + pthread_cond_destroy (&data->wait_cond); + _Jv_Free ((void *)data); +} + +void +_Jv_ThreadSetPriority (_Jv_Thread_t *data, jint prio) +{ +#ifdef _POSIX_THREAD_PRIORITY_SCHEDULING + if (data->flags & FLAG_START) + { + struct sched_param param; + + param.sched_priority = prio; + pthread_setschedparam (data->thread, SCHED_OTHER, ¶m); + } +#endif +} + +void +_Jv_ThreadRegister (_Jv_Thread_t *data) +{ + pthread_setspecific (_Jv_ThreadKey, data->thread_obj); + pthread_setspecific (_Jv_ThreadDataKey, data); + + // glibc 2.1.3 doesn't set the value of `thread' until after start_routine + // is called. Since it may need to be accessed from the new thread, work + // around the potential race here by explicitly setting it again. + data->thread = pthread_self (); + +# ifdef SLOW_PTHREAD_SELF + // Clear all self cache slots that might be needed by this thread. + int dummy; + int low_index = SC_INDEX(&dummy) + SC_CLEAR_MIN; + int high_index = SC_INDEX(&dummy) + SC_CLEAR_MAX; + for (int i = low_index; i <= high_index; ++i) + { + int current_index = i; + if (current_index < 0) + current_index += SELF_CACHE_SIZE; + if (current_index >= SELF_CACHE_SIZE) + current_index -= SELF_CACHE_SIZE; + _Jv_self_cache[current_index].high_sp_bits = BAD_HIGH_SP_VALUE; + } +# endif + // Block SIGCHLD which is used in natPosixProcess.cc. + _Jv_BlockSigchld(); +} + +void +_Jv_ThreadUnRegister () +{ + pthread_setspecific (_Jv_ThreadKey, NULL); + pthread_setspecific (_Jv_ThreadDataKey, NULL); +} + +// This function is called when a thread is started. We don't arrange +// to call the `run' method directly, because this function must +// return a value. +static void * +really_start (void *x) +{ + struct starter *info = (struct starter *) x; + + _Jv_ThreadRegister (info->data); + + info->method (info->data->thread_obj); + + if (! (info->data->flags & FLAG_DAEMON)) + { + pthread_mutex_lock (&daemon_mutex); + --non_daemon_count; + if (! non_daemon_count) + pthread_cond_signal (&daemon_cond); + pthread_mutex_unlock (&daemon_mutex); + } + + return NULL; +} + +void +_Jv_ThreadStart (java::lang::Thread *thread, _Jv_Thread_t *data, + _Jv_ThreadStartFunc *meth) +{ + struct sched_param param; + pthread_attr_t attr; + struct starter *info; + + if (data->flags & FLAG_START) + return; + data->flags |= FLAG_START; + + // Block SIGCHLD which is used in natPosixProcess.cc. + // The current mask is inherited by the child thread. + _Jv_BlockSigchld(); + + param.sched_priority = thread->getPriority(); + + pthread_attr_init (&attr); + pthread_attr_setschedparam (&attr, ¶m); + pthread_attr_setdetachstate (&attr, PTHREAD_CREATE_DETACHED); + + // Set stack size if -Xss option was given. + if (gcj::stack_size > 0) + { + int e = pthread_attr_setstacksize (&attr, gcj::stack_size); + if (e != 0) + JvFail (strerror (e)); + } + + info = (struct starter *) _Jv_AllocBytes (sizeof (struct starter)); + info->method = meth; + info->data = data; + + if (! thread->isDaemon()) + { + pthread_mutex_lock (&daemon_mutex); + ++non_daemon_count; + pthread_mutex_unlock (&daemon_mutex); + } + else + data->flags |= FLAG_DAEMON; + int r = pthread_create (&data->thread, &attr, really_start, (void *) info); + + pthread_attr_destroy (&attr); + + if (r) + { + const char* msg = "Cannot create additional threads"; + throw new java::lang::OutOfMemoryError (JvNewStringUTF (msg)); + } +} + +void +_Jv_ThreadWait (void) +{ + pthread_mutex_lock (&daemon_mutex); + if (non_daemon_count) + pthread_cond_wait (&daemon_cond, &daemon_mutex); + pthread_mutex_unlock (&daemon_mutex); +} + +#if defined(SLOW_PTHREAD_SELF) + +#include "sysdep/locks.h" + +// Support for pthread_self() lookup cache. +volatile self_cache_entry _Jv_self_cache[SELF_CACHE_SIZE]; + +_Jv_ThreadId_t +_Jv_ThreadSelf_out_of_line(volatile self_cache_entry *sce, size_t high_sp_bits) +{ + pthread_t self = pthread_self(); + sce -> high_sp_bits = high_sp_bits; + write_barrier(); + sce -> self = self; + return self; +} + +#endif /* SLOW_PTHREAD_SELF */ -- cgit v1.2.3