+/* This is a global variable set at program start time. It marks the
+ highest used stack address. */
+extern void *__libc_stack_end;
+
+
+/* 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
+
+struct layout
+{
+ struct layout *next;
+ void *return_address;
+};
+