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// Copyright 2014 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.
// Issue 7978. Stack tracing didn't work during cgo code after calling a Go
// callback. Make sure GC works and the stack trace is correct.
package cgotest
/*
#include <stdint.h>
void issue7978cb(void);
#if defined(__APPLE__) && defined(__arm__)
// on Darwin/ARM, libSystem doesn't provide implementation of the __sync_fetch_and_add
// primitive, and although gcc supports it, it doesn't inline its definition.
// Clang could inline its definition, so we require clang on Darwin/ARM.
#if defined(__clang__)
#define HAS_SYNC_FETCH_AND_ADD 1
#else
#define HAS_SYNC_FETCH_AND_ADD 0
#endif
#else
#define HAS_SYNC_FETCH_AND_ADD 1
#endif
// use ugly atomic variable sync since that doesn't require calling back into
// Go code or OS dependencies
static void issue7978c(uint32_t *sync) {
#if HAS_SYNC_FETCH_AND_ADD
while(__sync_fetch_and_add(sync, 0) != 0)
;
__sync_fetch_and_add(sync, 1);
while(__sync_fetch_and_add(sync, 0) != 2)
;
issue7978cb();
__sync_fetch_and_add(sync, 1);
while(__sync_fetch_and_add(sync, 0) != 6)
;
#endif
}
*/
import "C"
import (
"runtime"
"runtime/debug"
"strings"
"sync/atomic"
"testing"
)
var issue7978sync uint32
func issue7978check(t *testing.T, wantFunc string, badFunc string, depth int) {
runtime.GC()
buf := make([]byte, 65536)
trace := string(buf[:runtime.Stack(buf, true)])
for _, goroutine := range strings.Split(trace, "\n\n") {
if strings.Contains(goroutine, "test.issue7978go") {
trace := strings.Split(goroutine, "\n")
// look for the expected function in the stack
for i := 0; i < depth; i++ {
if badFunc != "" && strings.Contains(trace[1+2*i], badFunc) {
t.Errorf("bad stack: found %s in the stack:\n%s", badFunc, goroutine)
return
}
if strings.Contains(trace[1+2*i], wantFunc) {
return
}
}
t.Errorf("bad stack: didn't find %s in the stack:\n%s", wantFunc, goroutine)
return
}
}
t.Errorf("bad stack: goroutine not found. Full stack dump:\n%s", trace)
}
func issue7978wait(store uint32, wait uint32) {
if store != 0 {
atomic.StoreUint32(&issue7978sync, store)
}
for atomic.LoadUint32(&issue7978sync) != wait {
runtime.Gosched()
}
}
//export issue7978cb
func issue7978cb() {
// Force a stack growth from the callback to put extra
// pressure on the runtime. See issue #17785.
growStack(64)
issue7978wait(3, 4)
}
func growStack(n int) int {
var buf [128]int
if n == 0 {
return 0
}
return buf[growStack(n-1)]
}
func issue7978go() {
C.issue7978c((*C.uint32_t)(&issue7978sync))
issue7978wait(7, 8)
}
func test7978(t *testing.T) {
if runtime.Compiler == "gccgo" {
t.Skip("gccgo can not do stack traces of C code")
}
if C.HAS_SYNC_FETCH_AND_ADD == 0 {
t.Skip("clang required for __sync_fetch_and_add support on darwin/arm")
}
debug.SetTraceback("2")
issue7978sync = 0
go issue7978go()
// test in c code, before callback
issue7978wait(0, 1)
issue7978check(t, "_Cfunc_issue7978c(", "", 1)
// test in go code, during callback
issue7978wait(2, 3)
issue7978check(t, "test.issue7978cb(", "test.issue7978go", 3)
// test in c code, after callback
issue7978wait(4, 5)
issue7978check(t, "_Cfunc_issue7978c(", "_cgoexpwrap", 1)
// test in go code, after return from cgo
issue7978wait(6, 7)
issue7978check(t, "test.issue7978go(", "", 3)
atomic.StoreUint32(&issue7978sync, 8)
}