On 07/07/2017 01:13 AM, Lluís Vilanova wrote:
+ if (dc->ss_active && !dc->pstate_ss) {
+ /* Singlestep state is Active-pending.
+ * If we're in this state at the start of a TB then either
+ * a) we just took an exception to an EL which is being debugged
+ * and this is the first insn in the exception handler
+ * b) debug exceptions were masked and we just unmasked them
+ * without changing EL (eg by clearing PSTATE.D)
+ * In either case we're going to take a swstep exception in the
+ * "did not step an insn" case, and so the syndrome ISV and EX
+ * bits should be zero.
+ */
+ assert(dc->base.num_insns == 1);
+ gen_exception(EXCP_UDEF, syn_swstep(dc->ss_same_el, 0, 0),
+ default_exception_el(dc));
+ dc->base.is_jmp = DISAS_SKIP;
This is surely DISAS_EXC -- see gen_step_complete_exception.
Why introduce a new name?
The original code goes straight to done_generating here, and that's the purpose
of DISAS_SKIP (skip the code executed between the end of the loop and the
done_generating label).
That is the purpose of DISAS_EXC too. We've called a noreturn helper to raise
an exception and all following code is unreached. If there *was* any code
being emitted afterward, that is arguably a bug.
r~
