Re: [RFC][PATCH][PR 18376] gdb: Add process record and replay support for s390.

[Marcin KoÅcielnicki <koriakin at 0x04 dot net>]

Here comes v2.

I have added pseudo-support for TBEGIN (just to let it abort and fallback),
as well as PPA and ETND (on the off-chance someone uses them).

I have also found three missing break statements and fixed those.

The second patch implements single-stepping over a MVCLE+JO pair (as well
as other partial-execution instructions that can write memory).   I haven't
limitted it to record-only - AFAICT it doesn't cause any problems without
record (in fact, it should decrease context switches for large transfers),
but I'll restrict that if necessary.

As for the Uniersity of Syracuse machines, I do have access, and they are
only z196.

There's also an ambiguity in LCBB opcode documentation: it produces a 32-bit
unsigned result, but the text mentions storing it to the general register
(not to bits 32-63 of a general register, as is common for documentation
of proper 32-bit opcodes).  I don't have a vector-supporting machine, so
I can't check what is correct.  The patch goes the safe way and assumes
all 64 bits of GR can be changed.