gcc/libgo/runtime/go-rec-nb-small.c
Ian Lance Taylor 7a9389330e Add Go frontend, libgo library, and Go testsuite.
gcc/:
	* gcc.c (default_compilers): Add entry for ".go".
	* common.opt: Add -static-libgo as a driver option.
	* doc/install.texi (Configuration): Mention libgo as an option for
	--enable-shared.  Mention go as an option for --enable-languages.
	* doc/invoke.texi (Overall Options): Mention .go as a file name
	suffix.  Mention go as a -x option.
	* doc/frontends.texi (G++ and GCC): Mention Go as a supported
	language.
	* doc/sourcebuild.texi (Top Level): Mention libgo.
	* doc/standards.texi (Standards): Add section on Go language.
	Move references for other languages into their own section.
	* doc/contrib.texi (Contributors): Mention that I contributed the
	Go frontend.
gcc/testsuite/:
	* lib/go.exp: New file.
	* lib/go-dg.exp: New file.
	* lib/go-torture.exp: New file.
	* lib/target-supports.exp (check_compile): Match // Go.

From-SVN: r167407
2010-12-03 04:34:57 +00:00

128 lines
3.0 KiB
C

/* go-rec-nb-small.c -- nonblocking receive of something smal on a channel.
Copyright 2009 The Go Authors. All rights reserved.
Use of this source code is governed by a BSD-style
license that can be found in the LICENSE file. */
#include <stdint.h>
#include "go-assert.h"
#include "go-panic.h"
#include "channel.h"
/* Prepare to receive something on a nonblocking channel. */
int
__go_receive_nonblocking_acquire (struct __go_channel *channel)
{
int i;
_Bool has_data;
i = pthread_mutex_lock (&channel->lock);
__go_assert (i == 0);
while (channel->selected_for_receive)
{
i = pthread_cond_wait (&channel->cond, &channel->lock);
__go_assert (i == 0);
}
if (channel->is_closed
&& (channel->num_entries == 0
? channel->next_store == 0
: channel->next_fetch == channel->next_store))
{
if (channel->saw_close)
{
++channel->closed_op_count;
if (channel->closed_op_count >= MAX_CLOSED_OPERATIONS)
{
i = pthread_mutex_unlock (&channel->lock);
__go_assert (i == 0);
__go_panic_msg ("too many operations on closed channel");
}
}
channel->saw_close = 1;
__go_unlock_and_notify_selects (channel);
return RECEIVE_NONBLOCKING_ACQUIRE_CLOSED;
}
if (channel->num_entries > 0)
has_data = channel->next_fetch != channel->next_store;
else
{
if (channel->waiting_to_receive)
{
/* Some other goroutine is already waiting for data on this
channel, so we can't pick it up. */
has_data = 0;
}
else if (channel->next_store > 0)
{
/* There is data on the channel. */
has_data = 1;
}
else if (__go_synch_with_select (channel, 0))
{
/* We synched up with a select sending data, so there will
be data for us shortly. Tell the select to go, and then
wait for the data. */
__go_broadcast_to_select (channel);
while (channel->next_store == 0)
{
i = pthread_cond_wait (&channel->cond, &channel->lock);
__go_assert (i == 0);
}
has_data = 1;
}
else
{
/* Otherwise there is no data. */
has_data = 0;
}
if (has_data)
{
channel->waiting_to_receive = 1;
__go_assert (channel->next_store == 1);
}
}
if (!has_data)
{
i = pthread_mutex_unlock (&channel->lock);
__go_assert (i == 0);
return RECEIVE_NONBLOCKING_ACQUIRE_NODATA;
}
return RECEIVE_NONBLOCKING_ACQUIRE_DATA;
}
/* Receive something 64 bits or smaller on a nonblocking channel. */
struct __go_receive_nonblocking_small
__go_receive_nonblocking_small (struct __go_channel *channel)
{
struct __go_receive_nonblocking_small ret;
__go_assert (channel->element_size <= sizeof (uint64_t));
int data = __go_receive_nonblocking_acquire (channel);
if (data != RECEIVE_NONBLOCKING_ACQUIRE_DATA)
{
ret.__val = 0;
ret.__success = data == RECEIVE_NONBLOCKING_ACQUIRE_CLOSED;
return ret;
}
ret.__val = channel->data[channel->next_fetch];
__go_receive_release (channel);
ret.__success = 1;
return ret;
}