Prepare for radical source tree reorganization.zack/build-layout-experiment

All top-level files and directories are moved into a temporary storage
directory, REORG.TODO, except for files that will certainly still
exist in their current form at top level when we're done (COPYING,
COPYING.LIB, LICENSES, NEWS, README), all old ChangeLog files (which
are moved to the new directory OldChangeLogs, instead), and the
generated file INSTALL (which is just deleted; in the new order, there
will be no generated files checked into version control).

1 files changed, 90 insertions, 0 deletions

diff --git a/REORG.TODO/debug/backtrace.c b/REORG.TODO/debug/backtrace.c
new file mode 100644
index 0000000000..072fc2f7f8
--- /dev/null
+++ b/REORG.TODO/debug/backtrace.c
@@ -0,0 +1,90 @@
+/* Return backtrace of current program state.  Generic version.
+   Copyright (C) 1998-2017 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998.
+
+   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 <execinfo.h>
+#include <signal.h>
+#include <frame.h>
+#include <sigcontextinfo.h>
+#include <ldsodefs.h>
+
+/* This implementation assumes a stack layout that matches the defaults
+   used by gcc's `__builtin_frame_address' and `__builtin_return_address'
+   (FP is the frame pointer register):
+
+	  +-----------------+     +-----------------+
+    FP -> | previous FP --------> | previous FP ------>...
+	  |                 |     |                 |
+	  | return address  |     | return address  |
+	  +-----------------+     +-----------------+
+
+  */
+
+/* Get some notion of the current stack.  Need not be exactly the top
+   of the stack, just something somewhere in the current frame.  */
+#ifndef CURRENT_STACK_FRAME
+# define CURRENT_STACK_FRAME  ({ char __csf; &__csf; })
+#endif
+
+/* By default we assume that the stack grows downward.  */
+#ifndef INNER_THAN
+# define INNER_THAN <
+#endif
+
+/* By default assume the `next' pointer in struct layout points to the
+   next struct layout.  */
+#ifndef ADVANCE_STACK_FRAME
+# define ADVANCE_STACK_FRAME(next) ((struct layout *) (next))
+#endif
+
+/* By default, the frame pointer is just what we get from gcc.  */
+#ifndef FIRST_FRAME_POINTER
+# define FIRST_FRAME_POINTER  __builtin_frame_address (0)
+#endif
+
+int
+__backtrace (void **array, int size)
+{
+  struct layout *current;
+  void *top_frame;
+  void *top_stack;
+  int cnt = 0;
+
+  top_frame = FIRST_FRAME_POINTER;
+  top_stack = CURRENT_STACK_FRAME;
+
+  /* We skip the call to this function, it makes no sense to record it.  */
+  current = ((struct layout *) top_frame);
+  while (cnt < size)
+    {
+      if ((void *) current INNER_THAN top_stack
+	  || !((void *) current INNER_THAN __libc_stack_end))
+       /* This means the address is out of range.  Note that for the
+	  toplevel we see a frame pointer with value NULL which clearly is
+	  out of range.  */
+	break;
+
+      array[cnt++] = current->return_address;
+
+      current = ADVANCE_STACK_FRAME (current->next);
+    }
+
+  return cnt;
+}
+weak_alias (__backtrace, backtrace)
+libc_hidden_def (__backtrace)