libbacktrace/:

	* Initial implementation.

./:
	* MAINTAINERS (Various Maintainers): Add libbacktrace.
	* configure.ac (host_libs): Add libbacktrace.
	(target_libraries): Add libbacktrace.
	* Makefile.def (host_modules): Add libbacktrace.
	(target_modules): Likewise.
	* configure, Makefile.in: Rebuild.

gcc/go:
	* config-lang.in (target_libs): Add target-libbacktrace.

From-SVN: r191397
diff --git a/libbacktrace/simple.c b/libbacktrace/simple.c
new file mode 100644
index 0000000..f4e598f
--- /dev/null
+++ b/libbacktrace/simple.c
@@ -0,0 +1,108 @@
+/* simple.c -- The backtrace_simple function.
+   Copyright (C) 2012 Free Software Foundation, Inc.
+   Written by Ian Lance Taylor, Google.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+    (1) Redistributions of source code must retain the above copyright
+    notice, this list of conditions and the following disclaimer. 
+
+    (2) Redistributions in binary form must reproduce the above copyright
+    notice, this list of conditions and the following disclaimer in
+    the documentation and/or other materials provided with the
+    distribution.  
+    
+    (3) The name of the author may not be used to
+    endorse or promote products derived from this software without
+    specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
+INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.  */
+
+#include "config.h"
+
+#include "unwind.h"
+#include "backtrace.h"
+
+/* The simple_backtrace routine.  */
+
+/* Data passed through _Unwind_Backtrace.  */
+
+struct backtrace_simple_data
+{
+  /* Number of frames to skip.  */
+  int skip;
+  /* Library state.  */
+  struct backtrace_state *state;
+  /* Callback routine.  */
+  backtrace_simple_callback callback;
+  /* Error callback routine.  */
+  backtrace_error_callback error_callback;
+  /* Data to pass to callback routine.  */
+  void *data;
+  /* Value to return from backtrace.  */
+  int ret;
+};
+
+/* Unwind library callback routine.  This is passd to
+   _Unwind_Backtrace.  */
+
+static _Unwind_Reason_Code
+simple_unwind (struct _Unwind_Context *context, void *vdata)
+{
+  struct backtrace_simple_data *bdata = (struct backtrace_simple_data *) vdata;
+  uintptr_t pc;
+  int ip_before_insn = 0;
+
+#ifdef HAVE_GETIPINFO
+  pc = _Unwind_GetIPInfo (context, &ip_before_insn);
+#else
+  pc = _Unwind_GetIP (context);
+#endif
+
+  if (bdata->skip > 0)
+    {
+      --bdata->skip;
+      return _URC_NO_REASON;
+    }
+
+  if (!ip_before_insn)
+    --pc;
+
+  bdata->ret = bdata->callback (bdata->data, pc);
+
+  if (bdata->ret != 0)
+    return _URC_END_OF_STACK;
+
+  return _URC_NO_REASON;
+}
+
+/* Get a simple stack backtrace.  */
+
+int
+backtrace_simple (struct backtrace_state *state, int skip,
+		  backtrace_simple_callback callback,
+		  backtrace_error_callback error_callback, void *data)
+{
+  struct backtrace_simple_data bdata;
+
+  bdata.skip = skip + 1;
+  bdata.state = state;
+  bdata.callback = callback;
+  bdata.error_callback = error_callback;
+  bdata.data = data;
+  bdata.ret = 0;
+  _Unwind_Backtrace (simple_unwind, &bdata);
+  return bdata.ret;
+}