Fix altstack support in libgc by registering the bounds of the normal stack and the altstack with it.

1 files changed, 15 insertions, 2 deletions

diff --git a/libgc/darwin_stop_world.c b/libgc/darwin_stop_world.c
index 516b12c94c0..a1051f5ac4e 100644
--- a/libgc/darwin_stop_world.c
+++ b/libgc/darwin_stop_world.c
@@ -79,7 +79,7 @@ void GC_push_all_stacks() {
   kern_return_t r;
   GC_thread p;
   pthread_t me;
-  ptr_t lo, hi;
+  ptr_t lo, hi, altstack_lo, altstack_hi;
 #if defined(POWERPC)
   ppc_thread_state_t state;
   mach_msg_type_number_t thread_state_count = PPC_THREAD_STATE_COUNT;
@@ -252,6 +252,16 @@ void GC_push_all_stacks() {
 	hi = GC_stackbottom;
       else
 	hi = p->stack_end;
+
+	  if (p->altstack && lo >= p->altstack && lo <= p->altstack + p->altstack_size) {
+		  altstack_lo = lo;
+		  altstack_hi = p->altstack + p->altstack_size;
+		  lo = (char*)p->stack;
+		  hi = (char*)p->stack + p->stack_size;
+	  }	else {
+		  altstack_lo = NULL;
+	  }
+
 #if DEBUG_THREADS
       GC_printf3("Darwin: Stack for thread 0x%lx = [%lx,%lx)\n",
 		 (unsigned long) p -> id,
@@ -259,7 +269,10 @@ void GC_push_all_stacks() {
 		 (unsigned long) hi
 		 );
 #endif
-      GC_push_all_stack(lo,hi);
+	  if (lo)
+		  GC_push_all_stack(lo,hi);
+	  if (altstack_lo)
+		  GC_push_all_stack(altstack_lo,altstack_hi);
     } /* for(p=GC_threads[i]...) */
   } /* for(i=0;i<THREAD_TABLE_SZ...) */
 }