From e440a3286bc89368b8d3a8fd6accd47191790bf2 Mon Sep 17 00:00:00 2001
From: ian <ian@138bc75d-0d04-0410-961f-82ee72b054a4>
Date: Fri, 3 Dec 2010 04:34:57 +0000
Subject: Add Go frontend, libgo library, and Go testsuite.

gcc/:
	* gcc.c (default_compilers): Add entry for ".go".
	* common.opt: Add -static-libgo as a driver option.
	* doc/install.texi (Configuration): Mention libgo as an option for
	--enable-shared.  Mention go as an option for --enable-languages.
	* doc/invoke.texi (Overall Options): Mention .go as a file name
	suffix.  Mention go as a -x option.
	* doc/frontends.texi (G++ and GCC): Mention Go as a supported
	language.
	* doc/sourcebuild.texi (Top Level): Mention libgo.
	* doc/standards.texi (Standards): Add section on Go language.
	Move references for other languages into their own section.
	* doc/contrib.texi (Contributors): Mention that I contributed the
	Go frontend.
gcc/testsuite/:
	* lib/go.exp: New file.
	* lib/go-dg.exp: New file.
	* lib/go-torture.exp: New file.
	* lib/target-supports.exp (check_compile): Match // Go.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@167407 138bc75d-0d04-0410-961f-82ee72b054a4
---
 libgo/runtime/go-recover.c | 69 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 69 insertions(+)
 create mode 100644 libgo/runtime/go-recover.c

(limited to 'libgo/runtime/go-recover.c')

diff --git a/libgo/runtime/go-recover.c b/libgo/runtime/go-recover.c
new file mode 100644
index 00000000000..4de122e3b3e
--- /dev/null
+++ b/libgo/runtime/go-recover.c
@@ -0,0 +1,69 @@
+/* go-recover.c -- support for the go recover function.
+
+   Copyright 2010 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 "interface.h"
+#include "go-panic.h"
+#include "go-defer.h"
+
+/* This is called by a thunk to see if the real function should be
+   permitted to recover a panic value.  Recovering a value is
+   permitted if the thunk was called directly by defer.  RETADDR is
+   the return address of the function which is calling
+   __go_can_recover--this is, the thunk.  */
+
+_Bool
+__go_can_recover (const void* retaddr)
+{
+  struct __go_defer_stack *d;
+  const char* ret;
+  const char* dret;
+
+  if (__go_panic_defer == NULL)
+    return 0;
+  d = __go_panic_defer->__defer;
+  if (d == NULL)
+    return 0;
+
+  /* The panic which this function would recover is the one on the top
+     of the panic stack.  We do not want to recover it if that panic
+     was on the top of the panic stack when this function was
+     deferred.  */
+  if (d->__panic == __go_panic_defer->__panic)
+    return 0;
+
+  /* D->__RETADDR is the address of a label immediately following the
+     call to the thunk.  We can recover a panic if that is the same as
+     the return address of the thunk.  We permit a bit of slack in
+     case there is any code between the function return and the label,
+     such as an instruction to adjust the stack pointer.  */
+
+  ret = (const char *) retaddr;
+  dret = (const char *) d->__retaddr;
+  return ret <= dret && ret + 16 >= dret;
+}
+
+/* This is only called when it is valid for the caller to recover the
+   value on top of the panic stack, if there is one.  */
+
+struct __go_empty_interface
+__go_recover ()
+{
+  struct __go_panic_stack *p;
+
+  if (__go_panic_defer == NULL
+      || __go_panic_defer->__panic == NULL
+      || __go_panic_defer->__panic->__was_recovered)
+    {
+      struct __go_empty_interface ret;
+
+      ret.__type_descriptor = NULL;
+      ret.__object = NULL;
+      return ret;
+    }
+  p = __go_panic_defer->__panic;
+  p->__was_recovered = 1;
+  return p->__arg;
+}
-- 
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