gcc/libgo/runtime/go-defer.c
Ian Lance Taylor 75791bab05 runtime: use -fgo-c-header to build C header file
Use the new -fgo-c-header option to build a header file for the Go
    runtime code in libgo/go/runtime, and use the new header file in the C
    runtime code in libgo/runtime.  This will ensure that the Go code and C
    code share the same data structures as we convert the runtime from C to
    Go.
    
    The new file libgo/go/runtime/runtime2.go is copied from the Go 1.7
    release, and then edited to remove unnecessary data structures and
    modify others for use with libgo.
    
    The new file libgo/go/runtime/mcache.go is an initial version of the
    same files in the Go 1.7 release, and will be replaced by the Go 1.7
    file when we convert to the new memory allocator.
    
    The new file libgo/go/runtime/type.go describes the gccgo version of the
    reflection data structures, and replaces the Go 1.7 runtime file which
    describes the gc version of those structures.
    
    Using the new header file means changing a number of struct fields to
    use Go naming conventions (that is, no underscores) and to rename
    constants to have a leading underscore so that they are not exported
    from the Go package.  These names were updated in the C code.
    
    The C code was also changed to drop the thread-local variable m, as was
    done some time ago in the gc sources.  Now the m field is always
    accessed using g->m, where g is the single remaining thread-local
    variable.  This in turn required some adjustments to set g->m correctly
    in all cases.
    
    Also pass the new -fgo-compiling-runtime option when compiling the
    runtime package, although that option doesn't do anything yet.
    
    Reviewed-on: https://go-review.googlesource.com/28051

From-SVN: r239872
2016-08-30 21:07:47 +00:00

84 lines
2 KiB
C

/* 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"
/* This function is called each time we need to defer a call. */
void
__go_defer (_Bool *frame, void (*pfn) (void *), void *arg)
{
G *g;
Defer *n;
g = runtime_g ();
n = runtime_newdefer ();
n->next = g->_defer;
n->frame = frame;
n->_panic = g->_panic;
n->pfn = (uintptr) pfn;
n->arg = arg;
n->retaddr = 0;
n->makefunccanrecover = 0;
n->special = 0;
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)
{
Defer *d;
void (*pfn) (void *);
d = g->_defer;
pfn = (void (*) (void *)) d->pfn;
d->pfn = 0;
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. */
if (runtime_m () != NULL)
runtime_freedefer (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 = (uintptr) __builtin_extract_return_addr (retaddr);
return 0;
}