}
}
-#if !defined GC_SAVE_REGISTERS_ON_STACK && !defined GC_SETJMP_WORKS
+#ifndef HAVE___BUILTIN_UNWIND_INIT
+
+# ifdef GC_SETJMP_WORKS
+static void
+test_setjmp (void)
+{
+}
+# else
static bool setjmp_tested_p;
static int longjmps_done;
-#define SETJMP_WILL_LIKELY_WORK "\
+# define SETJMP_WILL_LIKELY_WORK "\
\n\
Emacs garbage collector has been changed to use conservative stack\n\
marking. Emacs has determined that the method it uses to do the\n\
Please mail the result to <emacs-devel@gnu.org>.\n\
"
-#define SETJMP_WILL_NOT_WORK "\
+# define SETJMP_WILL_NOT_WORK "\
\n\
Emacs garbage collector has been changed to use conservative stack\n\
marking. Emacs has determined that the default method it uses to do the\n\
static void
test_setjmp (void)
{
+ if (setjmp_tested_p)
+ return;
+ setjmp_tested_p = true;
char buf[10];
register int x;
sys_jmp_buf jbuf;
if (longjmps_done == 1)
sys_longjmp (jbuf, 1);
}
+# endif /* ! GC_SETJMP_WORKS */
+#endif /* ! HAVE___BUILTIN_UNWIND_INIT */
-#endif /* not GC_SAVE_REGISTERS_ON_STACK && not GC_SETJMP_WORKS */
+/* The type of an object near the stack top, whose address can be used
+ as a stack scan limit. */
+typedef union
+{
+ /* Align the stack top properly. Even if !HAVE___BUILTIN_UNWIND_INIT,
+ jmp_buf may not be aligned enough on darwin-ppc64. */
+ max_align_t o;
+#ifndef HAVE___BUILTIN_UNWIND_INIT
+ sys_jmp_buf j;
+ char c;
+#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
+/* Set *P to the address of the top of the stack. This must be a
+ macro, not a function, so that it is executed in the caller’s
+ environment. It is not inside a do-while so that its storage
+ survives the macro. */
+#ifdef HAVE___BUILTIN_UNWIND_INIT
+# define SET_STACK_TOP_ADDRESS(p) \
+ stacktop_sentry sentry; \
+ __builtin_unwind_init (); \
+ *(p) = &sentry
+#else
+# define SET_STACK_TOP_ADDRESS(p) \
+ stacktop_sentry sentry; \
+ __builtin_unwind_init (); \
+ test_setjmp (); \
+ sys_setjmp (sentry.j); \
+ *(p) = &sentry + (stack_bottom < &sentry.c)
+#endif
/* Mark live Lisp objects on the C stack.
We have to mark Lisp objects in CPU registers that can hold local
variables or are used to pass parameters.
- If GC_SAVE_REGISTERS_ON_STACK is defined, it should expand to
- something that either saves relevant registers on the stack, or
- calls mark_maybe_object passing it each register's contents.
-
- If GC_SAVE_REGISTERS_ON_STACK is not defined, the current
- implementation assumes that calling setjmp saves registers we need
+ This code assumes 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.
{
void *end;
struct thread_state *self = current_thread;
-
-#ifdef HAVE___BUILTIN_UNWIND_INIT
- /* Force callee-saved registers and register windows onto the stack.
- This is the preferred method if available, obviating the need for
- machine dependent methods. */
- __builtin_unwind_init ();
- end = &end;
-#else /* not HAVE___BUILTIN_UNWIND_INIT */
-#ifndef GC_SAVE_REGISTERS_ON_STACK
- /* jmp_buf may not be aligned enough on darwin-ppc64 */
- union aligned_jmpbuf {
- Lisp_Object o;
- sys_jmp_buf j;
- } j;
- volatile bool stack_grows_down_p = (char *) &j > (char *) stack_bottom;
-#endif
- /* This trick flushes the register windows so that all the state of
- the process is contained in the stack. */
- /* 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. */
-#ifdef __sparc__
-#if defined (__sparc64__) && defined (__FreeBSD__)
- /* FreeBSD does not have a ta 3 handler. */
- asm ("flushw");
-#else
- asm ("ta 3");
-#endif
-#endif
-
- /* Save registers that we need to see on the stack. We need to see
- registers used to hold register variables and registers used to
- pass parameters. */
-#ifdef GC_SAVE_REGISTERS_ON_STACK
- GC_SAVE_REGISTERS_ON_STACK (end);
-#else /* not GC_SAVE_REGISTERS_ON_STACK */
-
-#ifndef GC_SETJMP_WORKS /* If it hasn't been checked yet that
- setjmp will definitely work, test it
- and print a message with the result
- of the test. */
- if (!setjmp_tested_p)
- {
- setjmp_tested_p = 1;
- test_setjmp ();
- }
-#endif /* GC_SETJMP_WORKS */
-
- sys_setjmp (j.j);
- end = stack_grows_down_p ? (char *) &j + sizeof j : (char *) &j;
-#endif /* not GC_SAVE_REGISTERS_ON_STACK */
-#endif /* not HAVE___BUILTIN_UNWIND_INIT */
-
+ SET_STACK_TOP_ADDRESS (&end);
self->stack_top = end;
- (*func) (arg);
-
+ func (arg);
eassert (current_thread == self);
}
(void)
{
void *end;
-
-#ifdef HAVE___BUILTIN_UNWIND_INIT
- /* Force callee-saved registers and register windows onto the stack.
- This is the preferred method if available, obviating the need for
- machine dependent methods. */
- __builtin_unwind_init ();
- end = &end;
-#else /* not HAVE___BUILTIN_UNWIND_INIT */
-#ifndef GC_SAVE_REGISTERS_ON_STACK
- /* jmp_buf may not be aligned enough on darwin-ppc64 */
- union aligned_jmpbuf {
- Lisp_Object o;
- sys_jmp_buf j;
- } j;
- volatile bool stack_grows_down_p = (char *) &j > (char *) stack_base;
-#endif
- /* This trick flushes the register windows so that all the state of
- the process is contained in the stack. */
- /* 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. */
-#ifdef __sparc__
-#if defined (__sparc64__) && defined (__FreeBSD__)
- /* FreeBSD does not have a ta 3 handler. */
- asm ("flushw");
-#else
- asm ("ta 3");
-#endif
-#endif
-
- /* Save registers that we need to see on the stack. We need to see
- registers used to hold register variables and registers used to
- pass parameters. */
-#ifdef GC_SAVE_REGISTERS_ON_STACK
- GC_SAVE_REGISTERS_ON_STACK (end);
-#else /* not GC_SAVE_REGISTERS_ON_STACK */
-
-#ifndef GC_SETJMP_WORKS /* If it hasn't been checked yet that
- setjmp will definitely work, test it
- and print a message with the result
- of the test. */
- if (!setjmp_tested_p)
- {
- setjmp_tested_p = 1;
- test_setjmp ();
- }
-#endif /* GC_SETJMP_WORKS */
-
- sys_setjmp (j.j);
- end = stack_grows_down_p ? (char *) &j + sizeof j : (char *) &j;
-#endif /* not GC_SAVE_REGISTERS_ON_STACK */
-#endif /* not HAVE___BUILTIN_UNWIND_INIT */
+ SET_STACK_TOP_ADDRESS (&end);
return garbage_collect_1 (end);
}
void
init_alloc (void)
{
-#if !defined GC_SAVE_REGISTERS_ON_STACK && !defined GC_SETJMP_WORKS
- setjmp_tested_p = longjmps_done = 0;
-#endif
Vgc_elapsed = make_float (0.0);
gcs_done = 0;
projects / emacs.git / commitdiff