Remove use of R9, and fix associated bugs

We were passing the function address to stg_gc_prim_p in R9, which was
wrong because the call was a high-level call and didn't declare R9 as
a parameter.  Passing R9 as an argument is the right way, but
unfortunately that exposed another bug: we were using the same macro
in some low-level Cmm, where it is illegal to call functions with
arguments (see Note [syntax of cmm files]).  So we now have low-level
variants of STK_CHK() and STK_CHK_P() for use in low-level Cmm code.

1 files changed, 28 insertions, 12 deletions

diff --git a/rts/HeapStackCheck.cmm b/rts/HeapStackCheck.cmm
index e130cb3660..d826529aef 100644
--- a/rts/HeapStackCheck.cmm
+++ b/rts/HeapStackCheck.cmm
@@ -172,38 +172,54 @@ __stg_gc_enter_1 (P_ node)
    code in a few common cases.
    -------------------------------------------------------------------------- */
 
-stg_gc_prim ()
+stg_gc_prim (W_ fun)
 {
-    W_ fun;
-    fun = R9;
     call stg_gc_noregs ();
     jump fun();
 }
 
-stg_gc_prim_p (P_ arg)
+stg_gc_prim_p (P_ arg, W_ fun)
 {
-    W_ fun;
-    fun = R9;
     call stg_gc_noregs ();
     jump fun(arg);
 }
 
-stg_gc_prim_pp (P_ arg1, P_ arg2)
+stg_gc_prim_pp (P_ arg1, P_ arg2, W_ fun)
 {
-    W_ fun;
-    fun = R9;
     call stg_gc_noregs ();
     jump fun(arg1,arg2);
 }
 
-stg_gc_prim_n (W_ arg)
+stg_gc_prim_n (W_ arg, W_ fun)
 {
-    W_ fun;
-    fun = R9;
     call stg_gc_noregs ();
     jump fun(arg);
 }
 
+stg_gc_prim_p_ll_ret
+{
+    W_ fun;
+    P_ arg;
+    fun = Sp(2);
+    arg = Sp(1);
+    Sp_adj(3);
+    R1 = arg;
+    jump fun [R1];
+}
+
+stg_gc_prim_p_ll
+{
+    W_ fun;
+    P_ arg;
+    fun = R2;
+    arg = R1;
+    Sp_adj(-3);
+    Sp(2) = fun;
+    Sp(1) = arg;
+    Sp(0) = stg_gc_prim_p_ll_ret;
+    jump stg_gc_noregs [];
+}
+
 /* -----------------------------------------------------------------------------
    stg_enter_checkbh is just like stg_enter, except that we also call
    checkBlockingQueues().  The point of this is that the GC can