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go/misc/cgo/test/callback_c.c
Keith Randall 1b6807bb06 cgo: adjust return value location to account for stack copies.
During a cgo call, the stack can be copied.  This copy invalidates
the pointer that cgo has into the return value area.  To fix this
problem, pass the address of the location containing the stack
top value (which is in the G struct).  For cgo functions which
return values, read the stktop before and after the cgo call to
compute the adjustment necessary to write the return value.

Fixes #8771

LGTM=iant, rsc
R=iant, rsc, khr
CC=golang-codereviews
https://golang.org/cl/144130043
2014-09-25 07:59:01 -07:00

83 lines
1.1 KiB
C

// 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.
#include <sys/types.h>
#include <unistd.h>
#include "_cgo_export.h"
void
callback(void *f)
{
// use some stack space
volatile char data[64*1024];
data[0] = 0;
goCallback(f);
data[sizeof(data)-1] = 0;
}
void
callGoFoo(void)
{
extern void goFoo(void);
goFoo();
}
void
IntoC(void)
{
BackIntoGo();
}
#ifdef WIN32
#include <windows.h>
long long
mysleep(int seconds) {
long long st = GetTickCount();
sleep(seconds);
return st;
}
#else
#include <sys/time.h>
long long
mysleep(int seconds) {
long long st;
struct timeval tv;
gettimeofday(&tv, NULL);
st = tv.tv_sec * 1000 + tv.tv_usec / 1000;
sleep(seconds);
return st;
}
#endif
long long
twoSleep(int n)
{
BackgroundSleep(n);
return mysleep(n);
}
void
callGoStackCheck(void)
{
extern void goStackCheck(void);
goStackCheck();
}
int
returnAfterGrow(void)
{
extern int goReturnVal(void);
goReturnVal();
return 123456;
}
int
returnAfterGrowFromGo(void)
{
extern int goReturnVal(void);
return goReturnVal();
}