1 files changed, 95 insertions, 0 deletions
diff --git a/src/runtime/cgo/callbacks.go b/src/runtime/cgo/callbacks.go
new file mode 100644
index 000000000..1e8b59054
--- /dev/null
+++ b/src/runtime/cgo/callbacks.go
@@ -0,0 +1,95 @@
+// 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.
+
+package cgo
+
+import "unsafe"
+
+// These utility functions are available to be called from code
+// compiled with gcc via crosscall2.
+
+// cgocallback is defined in runtime
+//go:linkname _runtime_cgocallback runtime.cgocallback
+func _runtime_cgocallback(unsafe.Pointer, unsafe.Pointer, uintptr)
+
+// The declaration of crosscall2 is:
+//   void crosscall2(void (*fn)(void *, int), void *, int);
+//
+// We need to export the symbol crosscall2 in order to support
+// callbacks from shared libraries. This applies regardless of
+// linking mode.
+//go:cgo_export_static crosscall2
+//go:cgo_export_dynamic crosscall2
+
+// Allocate memory.  This allocates the requested number of bytes in
+// memory controlled by the Go runtime.  The allocated memory will be
+// zeroed.  You are responsible for ensuring that the Go garbage
+// collector can see a pointer to the allocated memory for as long as
+// it is valid, e.g., by storing a pointer in a local variable in your
+// C function, or in memory allocated by the Go runtime.  If the only
+// pointers are in a C global variable or in memory allocated via
+// malloc, then the Go garbage collector may collect the memory.
+
+// Call like this in code compiled with gcc:
+//   struct { size_t len; void *ret; } a;
+//   a.len = /* number of bytes to allocate */;
+//   crosscall2(_cgo_allocate, &a, sizeof a);
+//   /* Here a.ret is a pointer to the allocated memory.  */
+
+//go:linkname _runtime_cgo_allocate_internal runtime._cgo_allocate_internal
+var _runtime_cgo_allocate_internal byte
+
+//go:linkname _cgo_allocate _cgo_allocate
+//go:cgo_export_static _cgo_allocate
+//go:cgo_export_dynamic _cgo_allocate
+//go:nosplit
+func _cgo_allocate(a unsafe.Pointer, n int32) {
+	_runtime_cgocallback(unsafe.Pointer(&_runtime_cgo_allocate_internal), a, uintptr(n))
+}
+
+// Panic.  The argument is converted into a Go string.
+
+// Call like this in code compiled with gcc:
+//   struct { const char *p; } a;
+//   a.p = /* string to pass to panic */;
+//   crosscall2(_cgo_panic, &a, sizeof a);
+//   /* The function call will not return.  */
+
+//go:linkname _runtime_cgo_panic_internal runtime._cgo_panic_internal
+var _runtime_cgo_panic_internal byte
+
+//go:linkname _cgo_panic _cgo_panic
+//go:cgo_export_static _cgo_panic
+//go:cgo_export_dynamic _cgo_panic
+//go:nosplit
+func _cgo_panic(a unsafe.Pointer, n int32) {
+	_runtime_cgocallback(unsafe.Pointer(&_runtime_cgo_panic_internal), a, uintptr(n))
+}
+
+//go:cgo_import_static x_cgo_init
+//go:linkname x_cgo_init x_cgo_init
+//go:linkname _cgo_init _cgo_init
+var x_cgo_init byte
+var _cgo_init = &x_cgo_init
+
+//go:cgo_import_static x_cgo_malloc
+//go:linkname x_cgo_malloc x_cgo_malloc
+//go:linkname _cgo_malloc _cgo_malloc
+var x_cgo_malloc byte
+var _cgo_malloc = &x_cgo_malloc
+
+//go:cgo_import_static x_cgo_free
+//go:linkname x_cgo_free x_cgo_free
+//go:linkname _cgo_free _cgo_free
+var x_cgo_free byte
+var _cgo_free = &x_cgo_free
+
+//go:cgo_import_static x_cgo_thread_start
+//go:linkname x_cgo_thread_start x_cgo_thread_start
+//go:linkname _cgo_thread_start _cgo_thread_start
+var x_cgo_thread_start byte
+var _cgo_thread_start = &x_cgo_thread_start
+
+//go:cgo_export_static _cgo_topofstack
+//go:cgo_export_dynamic _cgo_topofstack