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/* go-defer.c -- manage the defer stack.
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 <stddef.h>
#include "runtime.h"
#include "go-alloc.h"
#include "go-panic.h"
#include "go-defer.h"
/* This function is called each time we need to defer a call. */
void
__go_defer (_Bool *frame, void (*pfn) (void *), void *arg)
{
G *g;
struct __go_defer_stack *n;
g = runtime_g ();
n = (struct __go_defer_stack *) __go_alloc (sizeof (struct __go_defer_stack));
n->__next = g->defer;
n->__frame = frame;
n->__panic = g->panic;
n->__pfn = pfn;
n->__arg = arg;
n->__retaddr = NULL;
n->__makefunc_can_recover = 0;
n->__free = 1;
g->defer = n;
}
/* This function is called when we want to undefer the stack. */
void
__go_undefer (_Bool *frame)
{
G *g;
g = runtime_g ();
while (g->defer != NULL && g->defer->__frame == frame)
{
struct __go_defer_stack *d;
void (*pfn) (void *);
M *m;
d = g->defer;
pfn = d->__pfn;
d->__pfn = NULL;
if (pfn != NULL)
(*pfn) (d->__arg);
g->defer = d->__next;
/* This may be called by a cgo callback routine to defer the
call to syscall.CgocallBackDone, in which case we will not
have a memory context. Don't try to free anything in that
case--the GC will release it later. */
m = runtime_m ();
if (m != NULL && m->mcache != NULL && d->__free)
__go_free (d);
/* Since we are executing a defer function here, we know we are
returning from the calling function. If the calling
function, or one of its callees, paniced, then the defer
functions would be executed by __go_panic. */
*frame = 1;
}
}
/* This function is called to record the address to which the deferred
function returns. This may in turn be checked by __go_can_recover.
The frontend relies on this function returning false. */
_Bool
__go_set_defer_retaddr (void *retaddr)
{
G *g;
g = runtime_g ();
if (g->defer != NULL)
g->defer->__retaddr = retaddr;
return 0;
}
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