runtime: darwin/amd64 library entry point
This is a practice run for darwin/arm.
Similar to the linux/amd64 shared library entry point. With several
pending linker changes I am successfully using this to implement
-buildmode=c-archive on darwin/amd64 with external linking.
The same entry point can be reused to implement -buildmode=c-shared
on darwin/amd64, however that will require further ld changes to
remove all text relocations.
One extra runtime change will follow this. According to the Go
execution modes document, -buildmode=c-archive should ignore the Go
main function. Right now it is being executed (and the process exits
if it doesn't block). I'm still searching for the right way to do
this.
Change-Id: Id97901ddd4d46970996f222bd79731dabff66a3d
Reviewed-on: https://go-review.googlesource.com/8652
Reviewed-by: Ian Lance Taylor <iant@golang.org>
diff --git a/src/runtime/os1_darwin.go b/src/runtime/os1_darwin.go
index 6c79bbb..9de6de9 100644
--- a/src/runtime/os1_darwin.go
+++ b/src/runtime/os1_darwin.go
@@ -81,7 +81,7 @@
var oset uint32
sigprocmask(_SIG_SETMASK, &sigset_all, &oset)
- errno := bsdthread_create(stk, mp, mp.g0, funcPC(mstart))
+ errno := bsdthread_create(stk, unsafe.Pointer(mp), funcPC(mstart))
sigprocmask(_SIG_SETMASK, &oset, nil)
if errno < 0 {
@@ -90,6 +90,36 @@
}
}
+// newosproc0 is a version of newosproc that can be called before the runtime
+// is initialized.
+//
+// As Go uses bsdthread_register when running without cgo, this function is
+// not safe to use after initialization as it does not pass an M as fnarg.
+//
+//go:nosplit
+func newosproc0(stacksize uintptr, fn unsafe.Pointer, fnarg uintptr) {
+ var dummy uint64
+ stack := sysAlloc(stacksize, &dummy)
+ if stack == nil {
+ write(2, unsafe.Pointer(&failallocatestack[0]), int32(len(failallocatestack)))
+ exit(1)
+ }
+ stk := unsafe.Pointer(uintptr(stack) + stacksize)
+
+ var oset uint32
+ sigprocmask(_SIG_SETMASK, &sigset_all, &oset)
+ errno := bsdthread_create(stk, fn, fnarg)
+ sigprocmask(_SIG_SETMASK, &oset, nil)
+
+ if errno < 0 {
+ write(2, unsafe.Pointer(&failthreadcreate[0]), int32(len(failthreadcreate)))
+ exit(1)
+ }
+}
+
+var failallocatestack = []byte("runtime: failed to allocate stack for the new OS thread\n")
+var failthreadcreate = []byte("runtime: failed to create new OS thread\n")
+
// Called to initialize a new m (including the bootstrap m).
// Called on the parent thread (main thread in case of bootstrap), can allocate memory.
func mpreinit(mp *m) {
