1 files changed, 54 insertions, 0 deletions
diff --git a/src/runtime/cgo.go b/src/runtime/cgo.go
new file mode 100644
index 0000000..395d54a
--- /dev/null
+++ b/src/runtime/cgo.go
@@ -0,0 +1,54 @@
+// 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.
+
+package runtime
+
+import "unsafe"
+
+//go:cgo_export_static main
+
+// Filled in by runtime/cgo when linked into binary.
+
+//go:linkname _cgo_init _cgo_init
+//go:linkname _cgo_thread_start _cgo_thread_start
+//go:linkname _cgo_sys_thread_create _cgo_sys_thread_create
+//go:linkname _cgo_notify_runtime_init_done _cgo_notify_runtime_init_done
+//go:linkname _cgo_callers _cgo_callers
+//go:linkname _cgo_set_context_function _cgo_set_context_function
+//go:linkname _cgo_yield _cgo_yield
+
+var (
+	_cgo_init                     unsafe.Pointer
+	_cgo_thread_start             unsafe.Pointer
+	_cgo_sys_thread_create        unsafe.Pointer
+	_cgo_notify_runtime_init_done unsafe.Pointer
+	_cgo_callers                  unsafe.Pointer
+	_cgo_set_context_function     unsafe.Pointer
+	_cgo_yield                    unsafe.Pointer
+)
+
+// iscgo is set to true by the runtime/cgo package
+var iscgo bool
+
+// cgoHasExtraM is set on startup when an extra M is created for cgo.
+// The extra M must be created before any C/C++ code calls cgocallback.
+var cgoHasExtraM bool
+
+// cgoUse is called by cgo-generated code (using go:linkname to get at
+// an unexported name). The calls serve two purposes:
+// 1) they are opaque to escape analysis, so the argument is considered to
+// escape to the heap.
+// 2) they keep the argument alive until the call site; the call is emitted after
+// the end of the (presumed) use of the argument by C.
+// cgoUse should not actually be called (see cgoAlwaysFalse).
+func cgoUse(interface{}) { throw("cgoUse should not be called") }
+
+// cgoAlwaysFalse is a boolean value that is always false.
+// The cgo-generated code says if cgoAlwaysFalse { cgoUse(p) }.
+// The compiler cannot see that cgoAlwaysFalse is always false,
+// so it emits the test and keeps the call, giving the desired
+// escape analysis result. The test is cheaper than the call.
+var cgoAlwaysFalse bool
+
+var cgo_yield = &_cgo_yield