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go/src/runtime/cgo.go
Ian Lance Taylor ea306ae625 runtime: support symbolic backtrace of C code in a cgo crash
The new function runtime.SetCgoTraceback may be used to register stack
traceback and symbolizer functions, written in C, to do a stack
traceback from cgo code.

There is a sample implementation of runtime.SetCgoSymbolizer at
github.com/ianlancetaylor/cgosymbolizer.  Just importing that package is
sufficient to get symbolic C backtraces.

Currently only supported on linux/amd64.

Change-Id: If96ee2eb41c6c7379d407b9561b87557bfe47341
Reviewed-on: https://go-review.googlesource.com/17761
Reviewed-by: Austin Clements <austin@google.com>
2016-04-01 04:13:44 +00:00

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Go

// 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_malloc _cgo_malloc
//go:linkname _cgo_free _cgo_free
//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
var (
_cgo_init unsafe.Pointer
_cgo_malloc unsafe.Pointer
_cgo_free unsafe.Pointer
_cgo_thread_start unsafe.Pointer
_cgo_sys_thread_create unsafe.Pointer
_cgo_notify_runtime_init_done unsafe.Pointer
_cgo_callers 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