1 // Copyright 2014 The Go Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style
3 // license that can be found in the LICENSE file.
9 //go:cgo_export_static main
11 // Filled in by runtime/cgo when linked into binary.
13 //go:linkname _cgo_init _cgo_init
14 //go:linkname _cgo_thread_start _cgo_thread_start
15 //go:linkname _cgo_sys_thread_create _cgo_sys_thread_create
16 //go:linkname _cgo_notify_runtime_init_done _cgo_notify_runtime_init_done
17 //go:linkname _cgo_callers _cgo_callers
18 //go:linkname _cgo_set_context_function _cgo_set_context_function
19 //go:linkname _cgo_yield _cgo_yield
22 _cgo_init unsafe.Pointer
23 _cgo_thread_start unsafe.Pointer
24 _cgo_sys_thread_create unsafe.Pointer
25 _cgo_notify_runtime_init_done unsafe.Pointer
26 _cgo_callers unsafe.Pointer
27 _cgo_set_context_function unsafe.Pointer
28 _cgo_yield unsafe.Pointer
31 // iscgo is set to true by the runtime/cgo package
34 // cgoHasExtraM is set on startup when an extra M is created for cgo.
35 // The extra M must be created before any C/C++ code calls cgocallback.
38 // cgoUse is called by cgo-generated code (using go:linkname to get at
39 // an unexported name). The calls serve two purposes:
40 // 1) they are opaque to escape analysis, so the argument is considered to
41 // escape to the heap.
42 // 2) they keep the argument alive until the call site; the call is emitted after
43 // the end of the (presumed) use of the argument by C.
44 // cgoUse should not actually be called (see cgoAlwaysFalse).
45 func cgoUse(any) { throw("cgoUse should not be called") }
47 // cgoAlwaysFalse is a boolean value that is always false.
48 // The cgo-generated code says if cgoAlwaysFalse { cgoUse(p) }.
49 // The compiler cannot see that cgoAlwaysFalse is always false,
50 // so it emits the test and keeps the call, giving the desired
51 // escape analysis result. The test is cheaper than the call.
52 var cgoAlwaysFalse bool
54 var cgo_yield = &_cgo_yield