--- /dev/null
+// 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 "../runtime.h"
+#include "../cgocall.h"
+
+// These utility functions are available to be called from code
+// compiled with gcc via crosscall2.
+
+// 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.
+#pragma dynexport crosscall2 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. */
+
+static void
+_cgo_allocate_internal(uintptr len, byte *ret)
+{
+ ret = runtime·mal(len);
+ FLUSH(&ret);
+}
+
+#pragma dynexport _cgo_allocate _cgo_allocate
+void
+_cgo_allocate(void *a, int32 n)
+{
+ runtime·cgocallback((void(*)(void))_cgo_allocate_internal, a, 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. */
+
+extern void ·cgoStringToEface(String, Eface*);
+
+static void
+_cgo_panic_internal(byte *p)
+{
+ String s;
+ Eface err;
+
+ s = runtime·gostring(p);
+ ·cgoStringToEface(s, &err);
+ runtime·panic(err);
+}
+
+#pragma dynexport _cgo_panic _cgo_panic
+void
+_cgo_panic(void *a, int32 n)
+{
+ runtime·cgocallback((void(*)(void))_cgo_panic_internal, a, n);
+}