| // 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 |
| |
| 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 |
| ) |
| |
| // 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 |