root/src/pkg/runtime/cgo/gcc_darwin_amd64.c

DEFINITIONS

1. inittls
2. x_cgo_init
3. _cgo_sys_thread_start
4. threadentry

// Copyright 2009 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.

#include <string.h> /* for strerror */
#include <pthread.h>
#include <signal.h>
#include "libcgo.h"

static void* threadentry(void*);
static pthread_key_t k1, k2;

#define magic1 (0x23581321345589ULL)

static void
inittls(void)
{
        uint64 x, y;
        pthread_key_t tofree[128], k;
        int i, ntofree;
        int havek1, havek2;

        /*
         * Same logic, code as darwin_386.c:/inittls, except that words
         * are 8 bytes long now, and the thread-local storage starts
         * at 0x60 on Leopard / Snow Leopard. So the offsets are
         * 0x60+8*0x108 = 0x8a0 and 0x60+8*0x109 = 0x8a8.
         *
         * The linker and runtime hard-code these constant offsets
         * from %gs where we expect to find m and g.
         * Known to ../../../cmd/6l/obj.c:/8a0
         * and to ../sys_darwin_amd64.s:/8a0
         *
         * As disgusting as on the 386; same justification.
         */
        havek1 = 0;
        havek2 = 0;
        ntofree = 0;
        while(!havek1 || !havek2) {
                if(pthread_key_create(&k, nil) < 0) {
                        fprintf(stderr, "runtime/cgo: pthread_key_create failed\n");
                        abort();
                }
                pthread_setspecific(k, (void*)magic1);
                asm volatile("movq %%gs:0x8a0, %0" : "=r"(x));
                asm volatile("movq %%gs:0x8a8, %0" : "=r"(y));
                if(x == magic1) {
                        havek1 = 1;
                        k1 = k;
                } else if(y == magic1) {
                        havek2 = 1;
                        k2 = k;
                } else {
                        if(ntofree >= nelem(tofree)) {
                                fprintf(stderr, "runtime/cgo: could not obtain pthread_keys\n");
                                fprintf(stderr, "\ttried");
                                for(i=0; i<ntofree; i++)
                                        fprintf(stderr, " %#x", (unsigned)tofree[i]);
                                fprintf(stderr, "\n");
                                abort();
                        }
                        tofree[ntofree++] = k;
                }
                pthread_setspecific(k, 0);
        }

        /*
         * We got the keys we wanted.  Free the others.
         */
        for(i=0; i<ntofree; i++)
                pthread_key_delete(tofree[i]);
}

void
x_cgo_init(G *g)
{
        pthread_attr_t attr;
        size_t size;

        pthread_attr_init(&attr);
        pthread_attr_getstacksize(&attr, &size);
        g->stackguard = (uintptr)&attr - size + 4096;
        pthread_attr_destroy(&attr);

        inittls();
}


void
_cgo_sys_thread_start(ThreadStart *ts)
{
        pthread_attr_t attr;
        sigset_t ign, oset;
        pthread_t p;
        size_t size;
        int err;

        sigfillset(&ign);
        pthread_sigmask(SIG_SETMASK, &ign, &oset);

        pthread_attr_init(&attr);
        pthread_attr_getstacksize(&attr, &size);
        ts->g->stackguard = size;
        err = pthread_create(&p, &attr, threadentry, ts);

        pthread_sigmask(SIG_SETMASK, &oset, nil);

        if (err != 0) {
                fprintf(stderr, "runtime/cgo: pthread_create failed: %s\n", strerror(err));
                abort();
        }
}

static void*
threadentry(void *v)
{
        ThreadStart ts;

        ts = *(ThreadStart*)v;
        free(v);

        ts.g->stackbase = (uintptr)&ts;

        /*
         * _cgo_sys_thread_start set stackguard to stack size;
         * change to actual guard pointer.
         */
        ts.g->stackguard = (uintptr)&ts - ts.g->stackguard + 4096;

        pthread_setspecific(k1, (void*)ts.g);
        pthread_setspecific(k2, (void*)ts.m);

        crosscall_amd64(ts.fn);
        return nil;
}