X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=rts%2FInterpreter.c;h=4324f7f44a415a97cea44f331e8796653a257bec;hb=8f52645bd99ee3e636a34826c0cbfc5939920da1;hp=ab59533666eab0a381fa0be6dc5503c7efed1e83;hpb=e0fcf61dca4dfac99cb5417e1bc4cbee18822cf2;p=ghc-hetmet.git

diff --git a/rts/Interpreter.c b/rts/Interpreter.c
index ab59533..4324f7f 100644
--- a/rts/Interpreter.c
+++ b/rts/Interpreter.c
@@ -63,6 +63,7 @@
     SpLim = cap->r.rCurrentTSO->stack + RESERVED_STACK_WORDS;
 
 #define SAVE_STACK_POINTERS			\
+    ASSERT(Sp > SpLim); \
     cap->r.rCurrentTSO->sp = Sp
 
 #define RETURN_TO_SCHEDULER(todo,retcode)	\
@@ -549,6 +550,16 @@ do_apply:
 		goto defer_apply_to_sched;
 	    }
 
+            // Stack check: we're about to unpack the PAP onto the
+            // stack.  The (+1) is for the (arity < n) case, where we
+            // also need space for an extra info pointer.
+            if (Sp - (pap->n_args + 1) < SpLim) {
+                Sp -= 2;
+                Sp[1] = (W_)tagged_obj;
+                Sp[0] = (W_)&stg_enter_info;
+                RETURN_TO_SCHEDULER(ThreadInterpret, StackOverflow);
+            }
+
 	    Sp++;
 	    arity = pap->arity;
 	    ASSERT(arity > 0);
@@ -1270,7 +1281,7 @@ run_BCO:
 	    // context switching: sometimes the scheduler can invoke
 	    // the interpreter with context_switch == 1, particularly
 	    // if the -C0 flag has been given on the cmd line.
-	    if (context_switch) {
+	    if (cap->context_switch) {
 		Sp--; Sp[0] = (W_)&stg_enter_info;
 		RETURN_TO_SCHEDULER(ThreadInterpret, ThreadYielding);
 	    }