nix/boehmgc-coroutine-sp-fallback.diff
John Ericson c18911602e Fix boehmgc-coroutine-sp-fallback.diff for FreeBSD
Our FreeBSD headers have `pthread_getattr_np`, but we get a link-time
error that is missing. The good news is that there is another similar
function which does exist, and the upstream project elsewhere does just
the [fallback code] we need.

As the fallback code indicates, the two functions are not identical
however as the other one needs explicit initialization. NetBSD supports
both in fact, and its [manpage] is therefore a good
resource on what the differences are.

[fallback code]: 07a6d0ee88/os_dep.c (L1266-L1272)

[manpage]: https://man.netbsd.org/pthread_attr_get_np.3
2023-09-20 09:04:42 -04:00

100 lines
4.1 KiB
Diff

diff --git a/darwin_stop_world.c b/darwin_stop_world.c
index 0468aaec..b348d869 100644
--- a/darwin_stop_world.c
+++ b/darwin_stop_world.c
@@ -356,6 +356,7 @@ GC_INNER void GC_push_all_stacks(void)
int nthreads = 0;
word total_size = 0;
mach_msg_type_number_t listcount = (mach_msg_type_number_t)THREAD_TABLE_SZ;
+ size_t stack_limit;
if (!EXPECT(GC_thr_initialized, TRUE))
GC_thr_init();
@@ -411,6 +412,19 @@ GC_INNER void GC_push_all_stacks(void)
GC_push_all_stack_sections(lo, hi, p->traced_stack_sect);
}
if (altstack_lo) {
+ // When a thread goes into a coroutine, we lose its original sp until
+ // control flow returns to the thread.
+ // While in the coroutine, the sp points outside the thread stack,
+ // so we can detect this and push the entire thread stack instead,
+ // as an approximation.
+ // We assume that the coroutine has similarly added its entire stack.
+ // This could be made accurate by cooperating with the application
+ // via new functions and/or callbacks.
+ stack_limit = pthread_get_stacksize_np(p->id);
+ if (altstack_lo >= altstack_hi || altstack_lo < altstack_hi - stack_limit) { // sp outside stack
+ altstack_lo = altstack_hi - stack_limit;
+ }
+
total_size += altstack_hi - altstack_lo;
GC_push_all_stack(altstack_lo, altstack_hi);
}
diff --git a/include/gc.h b/include/gc.h
index edab6c22..f2c61282 100644
--- a/include/gc.h
+++ b/include/gc.h
@@ -2172,6 +2172,11 @@ GC_API void GC_CALL GC_win32_free_heap(void);
(*GC_amiga_allocwrapper_do)(a,GC_malloc_atomic_ignore_off_page)
#endif /* _AMIGA && !GC_AMIGA_MAKINGLIB */
+#if !__APPLE__
+/* Patch doesn't work on apple */
+#define NIX_BOEHM_PATCH_VERSION 1
+#endif
+
#ifdef __cplusplus
} /* extern "C" */
#endif
diff --git a/pthread_stop_world.c b/pthread_stop_world.c
index b5d71e62..aed7b0bf 100644
--- a/pthread_stop_world.c
+++ b/pthread_stop_world.c
@@ -768,6 +768,8 @@ STATIC void GC_restart_handler(int sig)
/* world is stopped. Should not fail if it isn't. */
GC_INNER void GC_push_all_stacks(void)
{
+ size_t stack_limit;
+ pthread_attr_t pattr;
GC_bool found_me = FALSE;
size_t nthreads = 0;
int i;
@@ -851,6 +853,37 @@ GC_INNER void GC_push_all_stacks(void)
hi = p->altstack + p->altstack_size;
/* FIXME: Need to scan the normal stack too, but how ? */
/* FIXME: Assume stack grows down */
+ } else {
+#ifdef HAVE_PTHREAD_ATTR_GET_NP
+ if (!pthread_attr_init(&pattr)
+ || !pthread_attr_get_np(p->id, &pattr))
+#else /* HAVE_PTHREAD_GETATTR_NP */
+ if (pthread_getattr_np(p->id, &pattr))
+#endif
+ {
+ ABORT("GC_push_all_stacks: pthread_getattr_np failed!");
+ }
+ if (pthread_attr_getstacksize(&pattr, &stack_limit)) {
+ ABORT("GC_push_all_stacks: pthread_attr_getstacksize failed!");
+ }
+ if (pthread_attr_destroy(&pattr)) {
+ ABORT("GC_push_all_stacks: pthread_attr_destroy failed!");
+ }
+ // When a thread goes into a coroutine, we lose its original sp until
+ // control flow returns to the thread.
+ // While in the coroutine, the sp points outside the thread stack,
+ // so we can detect this and push the entire thread stack instead,
+ // as an approximation.
+ // We assume that the coroutine has similarly added its entire stack.
+ // This could be made accurate by cooperating with the application
+ // via new functions and/or callbacks.
+ #ifndef STACK_GROWS_UP
+ if (lo >= hi || lo < hi - stack_limit) { // sp outside stack
+ lo = hi - stack_limit;
+ }
+ #else
+ #error "STACK_GROWS_UP not supported in boost_coroutine2 (as of june 2021), so we don't support it in Nix."
+ #endif
}
GC_push_all_stack_sections(lo, hi, traced_stack_sect);
# ifdef STACK_GROWS_UP