src/pkg/runtime/stubs.goc

// 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
#include "runtime.h"
#include "arch_GOARCH.h"
#include "malloc.h"
#include "stack.h"
#include "../../cmd/ld/textflag.h"

// This file contains functions called by Go but written
// in C.  These functions are problematic for the garbage
// collector and stack copier because we don't have
// stack maps for them.  So we must ensure that the
// garbage collector and stack copier cannot see these
// frames.  So we impose the following invariants:

// 1) Functions should be marked NOSPLIT and call
//    out to only NOSPLIT functions (recursively).
// 2) Functions should not block.

// These invariants do not hold yet but will be established once we have
// finished converting runtime support code from C to Go.

#pragma textflag NOSPLIT
func golock(p *Lock) {
	runtime·lock(p);
}
#pragma textflag NOSPLIT
func gounlock(p *Lock) {
	runtime·unlock(p);
}

#pragma textflag NOSPLIT
func goreadgogc() (r int32) {
	r = runtime·readgogc();
}

// entry point for testing
// TODO: mcall and run on M stack
func gostringW(str Slice) (s String) {
	s = runtime·gostringw((uint16*)str.array);
}

#pragma textflag NOSPLIT
func gonanotime() (r int64) {
	r = runtime·nanotime();
}

#pragma textflag NOSPLIT
func goatomicloadp(p **byte) (v *byte) {
	v = runtime·atomicloadp(p);
}

#pragma textflag NOSPLIT
func goatomicstorep(p **byte, v *byte) {
	runtime·atomicstorep(p, v);
}

#pragma textflag NOSPLIT
func runtime·gocas(p *uint32, x uint32, y uint32) (ret bool) {
	ret = runtime·cas(p, x, y);
}

#pragma textflag NOSPLIT
func runtime·gocasx(p *uintptr, x uintptr, y uintptr) (ret bool) {
	ret = runtime·casp((void**)p, (void*)x, (void*)y);
}

#pragma textflag NOSPLIT
func runtime·acquirem() (ret *M) {
	ret = g->m;
	ret->locks++;
}

#pragma textflag NOSPLIT
func runtime·releasem(mp *M) {
	mp->locks--;
	if(mp->locks == 0 && g->preempt) {
		// restore the preemption request in case we've cleared it in newstack
		g->stackguard0 = StackPreempt;
	}
}

#pragma textflag NOSPLIT
func runtime·gomcache() (ret *MCache) {
	ret = g->m->mcache;
}

// For testing.
// TODO: find a better place for this.
func GCMask(x Eface) (mask Slice) {
	runtime·getgcmask(x.data, x.type, &mask.array, &mask.len);
	mask.cap = mask.len;
}

#pragma textflag NOSPLIT
func gopersistentalloc(size uintptr) (x *void) {
	// TODO: used only for itabs for now.  Need to make &mstats.other_sys arg parameterized.
	x = runtime·persistentalloc(size, 0, &mstats.other_sys);
}

#pragma textflag NOSPLIT
func reflect·typelinks() (ret Slice) {
        extern Type *typelink[], *etypelink[];
        ret.array = (byte*)typelink;
        ret.len = etypelink - typelink;
        ret.cap = ret.len;
}