runtime/cgo: darwin/arm cgo support

Change-Id: I936be12eed95b99d1d20ed16fb785182e1817b33
Reviewed-on: https://go-review.googlesource.com/2124
Reviewed-by: David Crawshaw <crawshaw@golang.org>

diff --git a/src/runtime/cgo/cgo.go b/src/runtime/cgo/cgo.go
index 8528692f7be9cb77994c443cbe47394350292c85..9a41399cd6e66c6504bc4df9c385e90af6fb2864 100644 (file)
--- a/src/runtime/cgo/cgo.go
+++ b/src/runtime/cgo/cgo.go
@@ -11,7 +11,7 @@ package cgo
 
 /*
 
-#cgo darwin LDFLAGS: -lpthread
+#cgo darwin,!arm LDFLAGS: -lpthread
 #cgo dragonfly LDFLAGS: -lpthread
 #cgo freebsd LDFLAGS: -lpthread
 #cgo android LDFLAGS: -llog

diff --git a/src/runtime/cgo/gcc_arm.S b/src/runtime/cgo/gcc_arm.S
index d5833bfad01bdc8445fe6cd0a7c51fdd09d03776..980ab579e4a062fc7f52c1dbb28a1949688b8456 100644 (file)
--- a/src/runtime/cgo/gcc_arm.S
+++ b/src/runtime/cgo/gcc_arm.S
@@ -11,6 +11,10 @@
 #define EXT(s) s
 #endif
 
+// Apple's ld64 wants 4-byte alignment for ARM code sections.
+// .align in both Apple as and GNU as treat n as aligning to 2**n bytes.
+.align 2
+
 /*
  * void crosscall_arm1(void (*fn)(void), void (*setg_gcc)(void *g), void *g)
  *

diff --git a/src/runtime/cgo/gcc_darwin_arm.c b/src/runtime/cgo/gcc_darwin_arm.c
new file mode 100644 (file)
index 0000000..d56c557
--- /dev/null
+++ b/src/runtime/cgo/gcc_darwin_arm.c
@@ -0,0 +1,99 @@
+// 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.
+
+#include <string.h> /* for strerror */
+#include <pthread.h>
+#include <signal.h>
+#include <limits.h>
+#include "libcgo.h"
+
+#define magic (0xe696c4f4U)
+
+// inittls allocates a thread-local storage slot for g.
+//
+// It finds the first available slot using pthread_key_create and uses
+// it as the offset value for runtime.tlsg.
+static void
+inittls(void **tlsg, void **tlsbase)
+{
+       pthread_key_t k;
+       int i, err;
+
+       err = pthread_key_create(&k, nil);
+       if(err != 0) {
+               fprintf(stderr, "runtime/cgo: pthread_key_create failed: %d\n", err);
+               abort();
+       }
+       //fprintf(stderr, "runtime/cgo: k = %d, tlsbase = %p\n", (int)k, tlsbase); // debug
+       pthread_setspecific(k, (void*)magic);
+       // The first key should be at 258.
+       for (i=0; i<PTHREAD_KEYS_MAX; i++) {
+               if (*(tlsbase+i) == (void*)magic) {
+                       *tlsg = (void*)(i*sizeof(void *));
+                       pthread_setspecific(k, 0);
+                       return;
+               }
+       }
+       fprintf(stderr, "runtime/cgo: could not find pthread key.\n");
+       abort();
+}
+
+static void *threadentry(void*);
+void (*setg_gcc)(void*);
+
+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);
+       size = 0;
+       pthread_attr_getstacksize(&attr, &size);
+       // Leave stacklo=0 and set stackhi=size; mstack will do the rest.
+       ts->g->stackhi = 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();
+       }
+}
+
+extern void crosscall_arm1(void (*fn)(void), void (*setg_gcc)(void*), void *g);
+static void*
+threadentry(void *v)
+{
+       ThreadStart ts;
+
+       ts = *(ThreadStart*)v;
+       free(v);
+
+       crosscall_arm1(ts.fn, setg_gcc, (void*)ts.g);
+       return nil;
+}
+
+void
+x_cgo_init(G *g, void (*setg)(void*), void **tlsg, void **tlsbase)
+{
+       pthread_attr_t attr;
+       size_t size;
+
+       setg_gcc = setg;
+       pthread_attr_init(&attr);
+       pthread_attr_getstacksize(&attr, &size);
+       g->stacklo = (uintptr)&attr - size + 4096;
+       pthread_attr_destroy(&attr);
+
+       // yes, tlsbase from mrc might not be correctly aligned.
+       inittls(tlsg, (void**)((uintptr)tlsbase & ~3));
+}