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// Copyright 2011 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.
//go:build !cgo
package fakecgo
import "unsafe"
//go:nosplit
func _cgo_sys_thread_start(ts *ThreadStart) {
var attr pthread_attr_t
var ign, oset sigset_t
var p pthread_t
var size size_t
var err int
//fprintf(stderr, "runtime/cgo: _cgo_sys_thread_start: fn=%p, g=%p\n", ts->fn, ts->g); // debug
sigfillset(&ign)
pthread_sigmask(SIG_SETMASK, &ign, &oset)
pthread_attr_init(&attr)
pthread_attr_getstacksize(&attr, &size)
// Leave stacklo=0 and set stackhi=size; mstart will do the rest.
ts.g.stackhi = uintptr(size)
err = _cgo_try_pthread_create(&p, &attr, unsafe.Pointer(threadentry_trampolineABI0), ts)
pthread_sigmask(SIG_SETMASK, &oset, nil)
if err != 0 {
print("fakecgo: pthread_create failed: ")
println(err)
abort()
}
}
// threadentry_trampolineABI0 maps the C ABI to Go ABI then calls the Go function
//
//go:linkname x_threadentry_trampoline threadentry_trampoline
var x_threadentry_trampoline byte
var threadentry_trampolineABI0 = &x_threadentry_trampoline
//go:nosplit
func threadentry(v unsafe.Pointer) unsafe.Pointer {
ts := *(*ThreadStart)(v)
free(v)
setg_trampoline(setg_func, uintptr(unsafe.Pointer(ts.g)))
// faking funcs in go is a bit a... involved - but the following works :)
fn := uintptr(unsafe.Pointer(&ts.fn))
(*(*func())(unsafe.Pointer(&fn)))()
return nil
}
// here we will store a pointer to the provided setg func
var setg_func uintptr
//go:nosplit
func x_cgo_init(g *G, setg uintptr) {
var size size_t
var attr *pthread_attr_t
/* The memory sanitizer distributed with versions of clang
before 3.8 has a bug: if you call mmap before malloc, mmap
may return an address that is later overwritten by the msan
library. Avoid this problem by forcing a call to malloc
here, before we ever call malloc.
This is only required for the memory sanitizer, so it's
unfortunate that we always run it. It should be possible
to remove this when we no longer care about versions of
clang before 3.8. The test for this is
misc/cgo/testsanitizers.
GCC works hard to eliminate a seemingly unnecessary call to
malloc, so we actually use the memory we allocate. */
setg_func = setg
attr = (*pthread_attr_t)(malloc(unsafe.Sizeof(*attr)))
if attr == nil {
println("fakecgo: malloc failed")
abort()
}
pthread_attr_init(attr)
pthread_attr_getstacksize(attr, &size)
// runtime/cgo uses __builtin_frame_address(0) instead of `uintptr(unsafe.Pointer(&size))`
// but this should be OK since we are taking the address of the first variable in this function.
g.stacklo = uintptr(unsafe.Pointer(&size)) - uintptr(size) + 4096
pthread_attr_destroy(attr)
free(unsafe.Pointer(attr))
}
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