In the past, the implementation of STFLE returned the facilities of the host
machine. This was not consistent in the following sense: Suppose the host
has a facility F installed and this facility implies the availability of an
insn X. Suppose further, that insn X is not supported in valgrind. 
An application progrm that tests the availability of insn X by checking
for its associated facility F will fail under valgrind when using X because
valgrind will SIGILL. Not so good.

This patch changes the STFLE behaviour to adjust the facilities of the
virtual machine according to what the set of insns that is actually
supported. It's an approximation, because for some facilities we only
support a subset of the insns enabled by that facility.

Fixes BZ 310931.


git-svn-id: svn://svn.valgrind.org/vex/trunk@2579 8f6e269a-dfd6-0310-a8e1-e2731360e62c
diff --git a/priv/guest_s390_toIR.c b/priv/guest_s390_toIR.c
index 68b108f..5a1b364 100644
--- a/priv/guest_s390_toIR.c
+++ b/priv/guest_s390_toIR.c
@@ -12482,6 +12482,11 @@
 }
 
 
+/* New insns are added here.
+   If an insn is contingent on a facility being installed also
+   check whether the list of supported facilities in function
+   s390x_dirtyhelper_STFLE needs updating */
+
 /*------------------------------------------------------------*/
 /*--- Build IR for special instructions                    ---*/
 /*------------------------------------------------------------*/