Fix ghc-bignum exceptions

We must ensure that exceptions are not simplified. Previously we used:

   case raiseDivZero of
      _ -> 0## -- dummyValue

But it was wrong because the evaluation of `raiseDivZero` was removed and
the dummy value was directly returned. See new Note [ghc-bignum exceptions].

I've also removed the exception triggering primops which were fragile.
We don't need them to be primops, we can have them exported by ghc-prim.

I've also added a test for #18359 which triggered this patch.

2 files changed, 19 insertions, 19 deletions

diff --git a/rts/Exception.cmm b/rts/Exception.cmm
index 587708e47e..3216edbcc4 100644
--- a/rts/Exception.cmm
+++ b/rts/Exception.cmm
@@ -14,6 +14,9 @@
 #include "RaiseAsync.h"
 
 import CLOSURE ghczmprim_GHCziTypes_True_closure;
+import CLOSURE base_GHCziExceptionziType_divZZeroException_closure;
+import CLOSURE base_GHCziExceptionziType_underflowException_closure;
+import CLOSURE base_GHCziExceptionziType_overflowException_closure;
 
 /* -----------------------------------------------------------------------------
    Exception Primitives
@@ -633,6 +636,22 @@ stg_raiseIOzh (P_ exception)
     jump stg_raisezh (exception);
 }
 
+
+stg_raiseDivZZerozh ()
+{
+    jump stg_raisezh(base_GHCziExceptionziType_divZZeroException_closure);
+}
+
+stg_raiseUnderflowzh ()
+{
+    jump stg_raisezh(base_GHCziExceptionziType_underflowException_closure);
+}
+
+stg_raiseOverflowzh ()
+{
+    jump stg_raisezh(base_GHCziExceptionziType_overflowException_closure);
+}
+
 /* The FFI doesn't support variadic C functions so we can't directly expose
  * `barf` to Haskell code. Instead we define "stg_panic#" and it is exposed to
  * Haskell programs in GHC.Prim.Panic.
diff --git a/rts/PrimOps.cmm b/rts/PrimOps.cmm
index 1bd30b3af0..1fd746edf6 100644
--- a/rts/PrimOps.cmm
+++ b/rts/PrimOps.cmm
@@ -31,9 +31,6 @@ import pthread_mutex_unlock;
 #endif
 import CLOSURE base_ControlziExceptionziBase_nestedAtomically_closure;
 import CLOSURE base_GHCziIOziException_heapOverflow_closure;
-import CLOSURE base_GHCziExceptionziType_divZZeroException_closure;
-import CLOSURE base_GHCziExceptionziType_underflowException_closure;
-import CLOSURE base_GHCziExceptionziType_overflowException_closure;
 import EnterCriticalSection;
 import LeaveCriticalSection;
 import CLOSURE ghczmprim_GHCziTypes_False_closure;
@@ -2601,19 +2598,3 @@ stg_setThreadAllocationCounterzh ( I64 counter )
     StgTSO_alloc_limit(CurrentTSO) = counter + TO_I64(offset);
     return ();
 }
-
-
-stg_raiseDivZZerozh ()
-{
-    jump stg_raisezh(base_GHCziExceptionziType_divZZeroException_closure);
-}
-
-stg_raiseUnderflowzh ()
-{
-    jump stg_raisezh(base_GHCziExceptionziType_underflowException_closure);
-}
-
-stg_raiseOverflowzh ()
-{
-    jump stg_raisezh(base_GHCziExceptionziType_overflowException_closure);
-}