1 files changed, 133 insertions, 0 deletions
diff --git a/REORG.TODO/sysdeps/x86_64/backtrace.c b/REORG.TODO/sysdeps/x86_64/backtrace.c
new file mode 100644
index 0000000000..15f425b410
--- /dev/null
+++ b/REORG.TODO/sysdeps/x86_64/backtrace.c
@@ -0,0 +1,133 @@
+/* Return backtrace of current program state.
+   Copyright (C) 2003-2017 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Jakub Jelinek <jakub@redhat.com>, 2003.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <libc-lock.h>
+#include <dlfcn.h>
+#include <execinfo.h>
+#include <stdlib.h>
+#include <unwind.h>
+
+struct trace_arg
+{
+  void **array;
+  _Unwind_Word cfa;
+  int cnt;
+  int size;
+};
+
+#ifdef SHARED
+static _Unwind_Reason_Code (*unwind_backtrace) (_Unwind_Trace_Fn, void *);
+static _Unwind_Ptr (*unwind_getip) (struct _Unwind_Context *);
+static _Unwind_Word (*unwind_getcfa) (struct _Unwind_Context *);
+static void *libgcc_handle;
+
+
+/* Dummy version in case libgcc_s does not contain the real code.  */
+static _Unwind_Word
+dummy_getcfa (struct _Unwind_Context *ctx __attribute__ ((unused)))
+{
+  return 0;
+}
+
+
+static void
+init (void)
+{
+  libgcc_handle = __libc_dlopen ("libgcc_s.so.1");
+
+  if (libgcc_handle == NULL)
+    return;
+
+  unwind_backtrace = __libc_dlsym (libgcc_handle, "_Unwind_Backtrace");
+  unwind_getip = __libc_dlsym (libgcc_handle, "_Unwind_GetIP");
+  if (unwind_getip == NULL)
+    unwind_backtrace = NULL;
+  unwind_getcfa = (__libc_dlsym (libgcc_handle, "_Unwind_GetCFA")
+		  ?: dummy_getcfa);
+}
+#else
+# define unwind_backtrace _Unwind_Backtrace
+# define unwind_getip _Unwind_GetIP
+# define unwind_getcfa _Unwind_GetCFA
+#endif
+
+static _Unwind_Reason_Code
+backtrace_helper (struct _Unwind_Context *ctx, void *a)
+{
+  struct trace_arg *arg = a;
+
+  /* We are first called with address in the __backtrace function.
+     Skip it.  */
+  if (arg->cnt != -1)
+    {
+      arg->array[arg->cnt] = (void *) unwind_getip (ctx);
+
+      /* Check whether we make any progress.  */
+      _Unwind_Word cfa = unwind_getcfa (ctx);
+
+      if (arg->cnt > 0 && arg->array[arg->cnt - 1] == arg->array[arg->cnt]
+	 && cfa == arg->cfa)
+       return _URC_END_OF_STACK;
+      arg->cfa = cfa;
+    }
+  if (++arg->cnt == arg->size)
+    return _URC_END_OF_STACK;
+  return _URC_NO_REASON;
+}
+
+int
+__backtrace (void **array, int size)
+{
+  struct trace_arg arg = { .array = array, .cfa = 0, .size = size, .cnt = -1 };
+
+  if (size <= 0)
+    return 0;
+
+#ifdef SHARED
+  __libc_once_define (static, once);
+
+  __libc_once (once, init);
+  if (unwind_backtrace == NULL)
+    return 0;
+#endif
+
+  unwind_backtrace (backtrace_helper, &arg);
+
+  /* _Unwind_Backtrace seems to put NULL address above
+     _start.  Fix it up here.  */
+  if (arg.cnt > 1 && arg.array[arg.cnt - 1] == NULL)
+    --arg.cnt;
+  return arg.cnt != -1 ? arg.cnt : 0;
+}
+weak_alias (__backtrace, backtrace)
+libc_hidden_def (__backtrace)
+
+
+#ifdef SHARED
+/* Free all resources if necessary.  */
+libc_freeres_fn (free_mem)
+{
+  unwind_backtrace = NULL;
+  if (libgcc_handle != NULL)
+    {
+      __libc_dlclose (libgcc_handle);
+      libgcc_handle = NULL;
+    }
+}
+#endif