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

2 files changed, 10 insertions, 0 deletions

diff --git a/libgc/include/gc.h b/libgc/include/gc.h
index d77de303e0d..7e5fd2ed840 100644
--- a/libgc/include/gc.h
+++ b/libgc/include/gc.h
@@ -841,6 +841,12 @@ GC_API GC_PTR GC_is_valid_displacement GC_PROTO((GC_PTR	p));
 /* Returns 1 if the calling thread is registered with the GC, 0 otherwise */
 GC_API int GC_thread_is_registered GC_PROTO((void));
 
+/* Notify the collector about the stack and the altstack of the current thread */
+/* STACK/STACK_SIZE is used to determine the stack dimensions when a thread is
+ * suspended while it is on an altstack.
+ */
+GC_API void GC_register_altstack GC_PROTO((void *stack, int stack_size, void *altstack, int altstack_size));
+
 /* Safer, but slow, pointer addition.  Probably useful mainly with 	*/
 /* a preprocessor.  Useful only for heap pointers.			*/
 #ifdef GC_DEBUG
diff --git a/libgc/include/private/pthread_support.h b/libgc/include/private/pthread_support.h
index 076a6d26ff9..4046a2666b8 100644
--- a/libgc/include/private/pthread_support.h
+++ b/libgc/include/private/pthread_support.h
@@ -47,6 +47,10 @@ typedef struct GC_Thread_Rep {
     				/* not need to be sent a signal to stop	*/
     				/* it.					*/
     ptr_t stack_end;		/* Cold end of the stack.		*/
+	ptr_t altstack; /* The start of the altstack if there is one, NULL otherwise */
+	int altstack_size; /* The size of the altstack if there is one */
+	ptr_t stack; /* The start of the normal stack */
+	int stack_size; /* The size of the normal stack */
 #   ifdef IA64
 	ptr_t backing_store_end;
 	ptr_t backing_store_ptr;