[PATCH 00/18] x86: new .insn directive

[Jan Beulich]

Especially when instructions which are not known to gas yet also take
register or, yet worse, memory operands, encoding such in code actually
wanting to make use of them is often difficult. Typically people resort
to hard-coding the involved registers, thus being able to express
things via .byte. To overcome this limitation (to a sufficient degree
at least), introduce .insn. This allows users to specify operands in
their "normal" shape (possibly in slightly altered order). Peculiarities
require two small syntax extensions; see the implementation or
documentation for details.

In order to re-use sufficiently much of the functionality md_assemble()
already uses, some adjustments to existing code were necessary. The one
item to call out here is the partial re-write of build_modrm_byte()
(patch 7), which actually turned out to simplify things. Subsequently
possible further tidying is carried out right away (patches 8 and 9),
even if not strictly related to the .insn work.

I'm pretty sure there are still corner cases which aren't taken care of
correctly. It's also quite possible that I've overlooked further places
in pre-existing code which need tweaking for .insn. People taking a
close look and/or playing with the new functionality would be much
appreciated.

The last patch in the series is strictly RFC, as I'm uncertain whether
we actually want this kind of a testcase.

01: introduce .insn directive
02: parse VEX and alike specifiers for .insn
03: parse special opcode modifiers for .insn
04: use set_rex_vrex() also for short-form handling
05: move more disp processing out of md_assemble()
06: adjust REX-prefix part of SSE2AVX test
07: re-work build_modrm_byte()'s register assignment
08: VexVVVV is now merely a boolean
09: drop "shimm" special case template expansions
10: AT&T: restrict recognition of the "absolute branch" prefix character
11: process instruction operands for .insn
12: decouple broadcast type and bytes fields
13: handle EVEX Disp8 for .insn
14: allow for multiple immediates in output_disp()
15: handle immediate operands for .insn
16: document .insn
17: convert testcases to use .insn
18: .insn example - VEX-encoded instructions of original Xeon Phi

Jan