// Copyright 2016 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.

//go:build darwin || linux

#include <stdint.h>

#include "libcgo.h"

#ifndef __has_feature

#define __has_feature(x) 0

#endif

#if __has_feature(memory_sanitizer)

#include <sanitizer/msan_interface.h>

#endif

// Call the user's traceback function and then call sigtramp.

// The runtime signal handler will jump to this code.

// We do it this way so that the user's traceback function will be called

// by a C function with proper unwind info.

void

x_cgo_callers(uintptr_t sig, void *info, void *context, void (*cgoTraceback)(struct cgoTracebackArg*), uintptr_t* cgoCallers, void (*sigtramp)(uintptr_t, void*, void*)) {

struct cgoTracebackArg arg;

arg.Context = 0;

arg.SigContext = (uintptr_t)(context);

arg.Buf = cgoCallers;

arg.Max = 32; // must match len(runtime.cgoCallers)

#if __has_feature(memory_sanitizer)

// This function is called directly from the signal handler.

// The arguments are passed in registers, so whether msan

// considers cgoCallers to be initialized depends on whether

// it considers the appropriate register to be initialized.

// That can cause false reports in rare cases.

// Explicitly unpoison the memory to avoid that.

// See issue #47543 for more details.

__msan_unpoison(&arg, sizeof arg);

#endif

_cgo_tsan_acquire();

(*cgoTraceback)(&arg);

_cgo_tsan_release();

sigtramp(sig, info, context);

}