#endif
} stacktop_sentry;
-/* Force callee-saved registers and register windows onto the stack.
- Use the platform-defined __builtin_unwind_init if available,
- obviating the need for machine dependent methods. */
-#ifndef HAVE___BUILTIN_UNWIND_INIT
-# ifdef __sparc__
- /* This trick flushes the register windows so that all the state of
- the process is contained in the stack.
- FreeBSD does not have a ta 3 handler, so handle it specially.
- FIXME: Code in the Boehm GC suggests flushing (with 'flushrs') is
- needed on ia64 too. See mach_dep.c, where it also says inline
- assembler doesn't work with relevant proprietary compilers. */
-# if defined __sparc64__ && defined __FreeBSD__
-# define __builtin_unwind_init() asm ("flushw")
-# else
-# define __builtin_unwind_init() asm ("ta 3")
-# endif
-# else
-# define __builtin_unwind_init() ((void) 0)
-# endif
-#endif
-
/* Yield an address close enough to the top of the stack that the
garbage collector need not scan above it. Callers should be
declared NO_INLINE. */
We have to mark Lisp objects in CPU registers that can hold local
variables or are used to pass parameters.
- This code assumes that calling setjmp saves registers we need
+ If __builtin_unwind_init is available, it should suffice to save
+ registers.
+
+ Otherwise, assume that calling setjmp saves registers we need
to see in a jmp_buf which itself lies on the stack. This doesn't
have to be true! It must be verified for each system, possibly
by taking a look at the source code of setjmp.
- If __builtin_unwind_init is available (defined by GCC >= 2.8) we
- can use it as a machine independent method to store all registers
- to the stack. In this case the macros described in the previous
- two paragraphs are not used.
-
Stack Layout
Architectures differ in the way their processor stack is organized.
extern void mark_stack (char const *, char const *);
extern void flush_stack_call_func1 (void (*func) (void *arg), void *arg);
+/* Force callee-saved registers and register windows onto the stack,
+ so that conservative garbage collection can see their values. */
+#ifndef HAVE___BUILTIN_UNWIND_INIT
+# ifdef __sparc__
+ /* This trick flushes the register windows so that all the state of
+ the process is contained in the stack.
+ FreeBSD does not have a ta 3 handler, so handle it specially.
+ FIXME: Code in the Boehm GC suggests flushing (with 'flushrs') is
+ needed on ia64 too. See mach_dep.c, where it also says inline
+ assembler doesn't work with relevant proprietary compilers. */
+# if defined __sparc64__ && defined __FreeBSD__
+# define __builtin_unwind_init() asm ("flushw")
+# else
+# define __builtin_unwind_init() asm ("ta 3")
+# endif
+# else
+# define __builtin_unwind_init() ((void) 0)
+# endif
+#endif
INLINE void
flush_stack_call_func (void (*func) (void *arg), void *arg)
{