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, 147 insertions, 0 deletions

diff --git a/REORG.TODO/sysdeps/s390/s390-64/backtrace.c b/REORG.TODO/sysdeps/s390/s390-64/backtrace.c
new file mode 100644
index 0000000000..4843db623a
--- /dev/null
+++ b/REORG.TODO/sysdeps/s390/s390-64/backtrace.c
@@ -0,0 +1,147 @@
+/* Return backtrace of current program state.  64 bit S/390 version.
+   Copyright (C) 2001-2017 Free Software Foundation, Inc.
+   Contributed by Martin Schwidefsky <schwidefsky@de.ibm.com>.
+   This file is part of the GNU C Library.
+
+   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 <stddef.h>
+#include <stdlib.h>
+#include <unwind.h>
+
+
+/* This is a global variable set at program start time.  It marks the
+   highest used stack address.  */
+extern void *__libc_stack_end;
+
+
+/* This is the stack layout we see for every non-leaf function.
+           size                    offset
+    %r15 ->    +------------------+
+             8 | back chain       |   0
+             8 | end of stack     |   8
+            32 | scratch          |  16
+            80 | save area r6-r15 |  48
+            16 | save area f4,f6  | 128
+            16 | empty            | 144
+               +------------------+
+   r14 in the save area holds the return address.
+*/
+
+struct layout
+{
+  long back_chain;
+  long end_of_stack;
+  long scratch[4];
+  long save_grps[10];
+  long save_fp[2];
+  long empty[2];
+};
+
+struct trace_arg
+{
+  void **array;
+  int cnt, size;
+};
+
+#ifdef SHARED
+static _Unwind_Reason_Code (*unwind_backtrace) (_Unwind_Trace_Fn, void *);
+static _Unwind_Ptr (*unwind_getip) (struct _Unwind_Context *);
+
+static void
+init (void)
+{
+  void *handle = __libc_dlopen ("libgcc_s.so.1");
+
+  if (handle == NULL)
+    return;
+
+  unwind_backtrace = __libc_dlsym (handle, "_Unwind_Backtrace");
+  unwind_getip = __libc_dlsym (handle, "_Unwind_GetIP");
+  if (unwind_getip == NULL)
+    unwind_backtrace = NULL;
+}
+
+static int
+__backchain_backtrace (void **array, int size)
+{
+  /* We assume that all the code is generated with frame pointers set.  */
+  struct layout *stack;
+  int cnt = 0;
+
+  __asm__ ("LGR  %0,%%r15" : "=d" (stack) );
+  /* We skip the call to this function, it makes no sense to record it.  */
+  stack = (struct layout *) stack->back_chain;
+  while (cnt < size)
+    {
+      if (stack == NULL || (void *) stack > __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++] = (void *) stack->save_grps[8];
+
+      stack = (struct layout *) stack->back_chain;
+    }
+
+  return cnt;
+}
+#else
+# define unwind_backtrace _Unwind_Backtrace
+# define unwind_getip _Unwind_GetIP
+#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);
+  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, .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 __backchain_backtrace (array, size);
+#endif
+
+  unwind_backtrace (backtrace_helper, &arg);
+
+  return arg.cnt != -1 ? arg.cnt : 0;
+}
+
+weak_alias (__backtrace, backtrace)
+libc_hidden_def (__backtrace)