0d3dd8fb65
Remove support for _cgo_allocate. It was removed from the gc
toolchain in Go 1.5, so it is unlikely that anybody is trying to use it.
Reviewed-on: https://go-review.googlesource.com/34557
From-SVN: r243805
111 lines
2.8 KiB
Go
111 lines
2.8 KiB
Go
// Copyright 2016 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package runtime
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import (
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"runtime/internal/atomic"
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_ "unsafe"
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)
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// For historical reasons these functions are called as though they
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// were in the syscall package.
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//go:linkname Cgocall syscall.Cgocall
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//go:linkname CgocallDone syscall.CgocallDone
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//go:linkname CgocallBack syscall.CgocallBack
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//go:linkname CgocallBackDone syscall.CgocallBackDone
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// A routine that may be called by SWIG.
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//go:linkname _cgo_panic _cgo_panic
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// iscgo is set to true if the cgo tool sets the C variable runtime_iscgo
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// to true.
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var iscgo bool
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// cgoHasExtraM is set on startup when an extra M is created for cgo.
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// The extra M must be created before any C/C++ code calls cgocallback.
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var cgoHasExtraM bool
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// Cgocall prepares to call from code written in Go to code written in
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// C/C++. This takes the current goroutine out of the Go scheduler, as
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// though it were making a system call. Otherwise the program can
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// lookup if the C code blocks. The idea is to call this function,
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// then immediately call the C/C++ function. After the C/C++ function
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// returns, call cgocalldone. The usual Go code would look like
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// syscall.Cgocall()
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// defer syscall.Cgocalldone()
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// cfunction()
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func Cgocall() {
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lockOSThread()
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mp := getg().m
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mp.ncgocall++
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mp.ncgo++
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entersyscall(0)
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}
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// CgocallDone prepares to return to Go code from C/C++ code.
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func CgocallDone() {
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gp := getg()
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if gp == nil {
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throw("no g in CgocallDone")
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}
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gp.m.ncgo--
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// If we are invoked because the C function called _cgo_panic,
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// then _cgo_panic will already have exited syscall mode.
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if gp.atomicstatus == _Gsyscall {
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exitsyscall(0)
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}
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unlockOSThread()
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}
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// CgocallBack is used when calling from C/C++ code into Go code.
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// The usual approach is
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// syscall.CgocallBack()
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// defer syscall.CgocallBackDone()
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// gofunction()
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//go:nosplit
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func CgocallBack() {
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if getg() == nil || getg().m == nil {
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needm(0)
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mp := getg().m
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mp.dropextram = true
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}
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exitsyscall(0)
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if getg().m.ncgo == 0 {
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// The C call to Go came from a thread created by C.
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// The C call to Go came from a thread not currently running
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// any Go. In the case of -buildmode=c-archive or c-shared,
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// this call may be coming in before package initialization
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// is complete. Wait until it is.
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<-main_init_done
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}
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mp := getg().m
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if mp.needextram || atomic.Load(&extraMWaiters) > 0 {
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mp.needextram = false
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newextram()
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}
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}
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// CgocallBackDone prepares to return to C/C++ code that has called
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// into Go code.
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func CgocallBackDone() {
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entersyscall(0)
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mp := getg().m
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if mp.dropextram && mp.ncgo == 0 {
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mp.dropextram = false
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dropm()
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}
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}
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// _cgo_panic may be called by SWIG code to panic.
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func _cgo_panic(p *byte) {
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exitsyscall(0)
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panic(gostringnocopy(p))
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}
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