8c, 8l dynamic loading support.

better mach binaries.
cgo working on darwin+linux amd64+386.
eliminated context switches - pi is 30x faster.
add libcgo to build.

on snow leopard:
  - non-cgo binaries work; all tests pass.
  - cgo binaries work on amd64 but not 386.

R=r
DELTA=2031  (1316 added, 626 deleted, 89 changed)
OCL=35264
CL=35304

1 files changed, 57 insertions, 0 deletions

diff --git a/src/libcgo/linux_386.c b/src/libcgo/linux_386.c
new file mode 100644
index 000000000..9d02455cc
--- /dev/null
+++ b/src/libcgo/linux_386.c
@@ -0,0 +1,57 @@
+// 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 <pthread.h>
+#include "libcgo.h"
+
+static void *threadentry(void*);
+
+void
+initcgo(void)
+{
+}
+
+void
+libcgo_sys_thread_start(ThreadStart *ts)
+{
+	pthread_attr_t attr;
+	pthread_t p;
+	size_t size;
+
+	pthread_attr_init(&attr);
+	pthread_attr_getstacksize(&attr, &size);
+	ts->g->stackguard = size;
+	pthread_create(&p, &attr, threadentry, ts);
+}
+
+static void*
+threadentry(void *v)
+{
+	ThreadStart ts;
+
+	ts = *(ThreadStart*)v;
+	free(v);
+
+	ts.g->stackbase = (uintptr)&ts;
+
+	/*
+	 * libcgo_sys_thread_start set stackguard to stack size;
+	 * change to actual guard pointer.
+	 */
+	ts.g->stackguard = (uintptr)&ts - ts.g->stackguard + 4096;
+
+	/*
+	 * Set specific keys.  On Linux/ELF, the thread local storage
+	 * is just before %gs:0.  Our dynamic 8.out's reserve 8 bytes
+	 * for the two words g and m at %gs:-8 and %gs:-4.
+	 */
+	asm volatile (
+		"movl %0, %%gs:-8\n"	// MOVL g, -8(GS)
+		"movl %1, %%gs:-4\n"	// MOVL m, -4(GS)
+		:: "r"(ts.g), "r"(ts.m)
+	);
+
+	crosscall_386(ts.fn);
+	return nil;
+}