runtime: copy internal locking code from Go 1.7 runtime

    
    Remove the old locking code written in C.
    
    Add a shell script mkrsysinfo.sh to generate the runtime_sysinfo.go
    file, so that we can get Go copies of the system time structures and
    other types.
    
    Tweak the compiler so that when compiling the runtime package the
    address operator does not cause local variables to escape.  When the gc
    compiler compiles the runtime, an escaping local variable is treated as
    an error.  We should implement that, instead of this change, when escape
    analysis is turned on.
    
    Tweak the compiler so that the generated C header does not include names
    that start with an underscore followed by a non-upper-case letter,
    except for the special cases of _defer and _panic.  Otherwise we
    translate C types to Go in runtime_sysinfo.go and then generate those Go
    types back as C types in runtime.inc, which is useless and painful for
    the C code.
    
    Change entersyscall and friends to take a dummy argument, as the gc
    versions do, to simplify calls from the shared code.
    
    Reviewed-on: https://go-review.googlesource.com/30079

From-SVN: r240657

1 files changed, 0 insertions, 204 deletions

diff --git a/libgo/runtime/lock_futex.c b/libgo/runtime/lock_futex.c
deleted file mode 100644
index 33ef073..0000000
--- a/libgo/runtime/lock_futex.c
+++ /dev/null
@@ -1,204 +0,0 @@
-// Copyright 2011 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.
-
-// +build dragonfly freebsd linux
-
-#include "runtime.h"
-
-// This implementation depends on OS-specific implementations of
-//
-//	runtime_futexsleep(uint32 *addr, uint32 val, int64 ns)
-//		Atomically,
-//			if(*addr == val) sleep
-//		Might be woken up spuriously; that's allowed.
-//		Don't sleep longer than ns; ns < 0 means forever.
-//
-//	runtime_futexwakeup(uint32 *addr, uint32 cnt)
-//		If any procs are sleeping on addr, wake up at most cnt.
-
-enum
-{
-	MUTEX_UNLOCKED = 0,
-	MUTEX_LOCKED = 1,
-	MUTEX_SLEEPING = 2,
-
-	ACTIVE_SPIN = 4,
-	ACTIVE_SPIN_CNT = 30,
-	PASSIVE_SPIN = 1,
-};
-
-// Possible lock states are MUTEX_UNLOCKED, MUTEX_LOCKED and MUTEX_SLEEPING.
-// MUTEX_SLEEPING means that there is presumably at least one sleeping thread.
-// Note that there can be spinning threads during all states - they do not
-// affect mutex's state.
-void
-runtime_lock(Lock *l)
-{
-	uint32 i, v, wait, spin;
-
-	if(runtime_m()->locks++ < 0)
-		runtime_throw("runtime_lock: lock count");
-
-	// Speculative grab for lock.
-	v = runtime_xchg((uint32*)&l->key, MUTEX_LOCKED);
-	if(v == MUTEX_UNLOCKED)
-		return;
-
-	// wait is either MUTEX_LOCKED or MUTEX_SLEEPING
-	// depending on whether there is a thread sleeping
-	// on this mutex.  If we ever change l->key from
-	// MUTEX_SLEEPING to some other value, we must be
-	// careful to change it back to MUTEX_SLEEPING before
-	// returning, to ensure that the sleeping thread gets
-	// its wakeup call.
-	wait = v;
-
-	// On uniprocessor's, no point spinning.
-	// On multiprocessors, spin for ACTIVE_SPIN attempts.
-	spin = 0;
-	if(runtime_ncpu > 1)
-		spin = ACTIVE_SPIN;
-
-	for(;;) {
-		// Try for lock, spinning.
-		for(i = 0; i < spin; i++) {
-			while(l->key == MUTEX_UNLOCKED)
-				if(runtime_cas((uint32*)&l->key, MUTEX_UNLOCKED, wait))
-					return;
-			runtime_procyield(ACTIVE_SPIN_CNT);
-		}
-
-		// Try for lock, rescheduling.
-		for(i=0; i < PASSIVE_SPIN; i++) {
-			while(l->key == MUTEX_UNLOCKED)
-				if(runtime_cas((uint32*)&l->key, MUTEX_UNLOCKED, wait))
-					return;
-			runtime_osyield();
-		}
-
-		// Sleep.
-		v = runtime_xchg((uint32*)&l->key, MUTEX_SLEEPING);
-		if(v == MUTEX_UNLOCKED)
-			return;
-		wait = MUTEX_SLEEPING;
-		runtime_futexsleep((uint32*)&l->key, MUTEX_SLEEPING, -1);
-	}
-}
-
-void
-runtime_unlock(Lock *l)
-{
-	uint32 v;
-
-	v = runtime_xchg((uint32*)&l->key, MUTEX_UNLOCKED);
-	if(v == MUTEX_UNLOCKED)
-		runtime_throw("unlock of unlocked lock");
-	if(v == MUTEX_SLEEPING)
-		runtime_futexwakeup((uint32*)&l->key, 1);
-
-	if(--runtime_m()->locks < 0)
-		runtime_throw("runtime_unlock: lock count");
-}
-
-// One-time notifications.
-void
-runtime_noteclear(Note *n)
-{
-	n->key = 0;
-}
-
-void
-runtime_notewakeup(Note *n)
-{
-	uint32 old;
-
-	old = runtime_xchg((uint32*)&n->key, 1);
-	if(old != 0) {
-		runtime_printf("notewakeup - double wakeup (%d)\n", old);
-		runtime_throw("notewakeup - double wakeup");
-	}
-	runtime_futexwakeup((uint32*)&n->key, 1);
-}
-
-void
-runtime_notesleep(Note *n)
-{
-	M *m = runtime_m();
-
-  /* For gccgo it's OK to sleep in non-g0, and it happens in
-     stoptheworld because we have not implemented preemption.
-
-	if(runtime_g() != runtime_m()->g0)
-		runtime_throw("notesleep not on g0");
-  */
-	while(runtime_atomicload((uint32*)&n->key) == 0) {
-		m->blocked = true;
-		runtime_futexsleep((uint32*)&n->key, 0, -1);
-		m->blocked = false;
-	}
-}
-
-static bool
-notetsleep(Note *n, int64 ns, int64 deadline, int64 now)
-{
-	M *m = runtime_m();
-
-	// Conceptually, deadline and now are local variables.
-	// They are passed as arguments so that the space for them
-	// does not count against our nosplit stack sequence.
-
-	if(ns < 0) {
-		while(runtime_atomicload((uint32*)&n->key) == 0) {
-			m->blocked = true;
-			runtime_futexsleep((uint32*)&n->key, 0, -1);
-			m->blocked = false;
-		}
-		return true;
-	}
-
-	if(runtime_atomicload((uint32*)&n->key) != 0)
-		return true;
-
-	deadline = runtime_nanotime() + ns;
-	for(;;) {
-		m->blocked = true;
-		runtime_futexsleep((uint32*)&n->key, 0, ns);
-		m->blocked = false;
-		if(runtime_atomicload((uint32*)&n->key) != 0)
-			break;
-		now = runtime_nanotime();
-		if(now >= deadline)
-			break;
-		ns = deadline - now;
-	}
-	return runtime_atomicload((uint32*)&n->key) != 0;
-}
-
-bool
-runtime_notetsleep(Note *n, int64 ns)
-{
-	bool res;
-
-	if(runtime_g() != runtime_m()->g0 && !runtime_m()->gcing)
-		runtime_throw("notetsleep not on g0");
-
-	res = notetsleep(n, ns, 0, 0);
-	return res;
-}
-
-// same as runtime_notetsleep, but called on user g (not g0)
-// calls only nosplit functions between entersyscallblock/exitsyscall
-bool
-runtime_notetsleepg(Note *n, int64 ns)
-{
-	bool res;
-
-	if(runtime_g() == runtime_m()->g0)
-		runtime_throw("notetsleepg on g0");
-
-	runtime_entersyscallblock();
-	res = notetsleep(n, ns, 0, 0);
-	runtime_exitsyscall();
-	return res;
-}