[all-commits] [llvm/llvm-project] 42d484: [X86][MC] Support encoding/decoding for JMPABS (#7...

[Shengchen Kan via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 42d484082cd190400e0e493a8d679762ce0efbba
      https://github.com/llvm/llvm-project/commit/42d484082cd190400e0e493a8d679762ce0efbba
  Author: Shengchen Kan <shengchen.kan at intel.com>
  Date:   2023-11-22 (Wed, 22 Nov 2023)

  Changed paths:
    M llvm/include/llvm/Support/X86DisassemblerDecoderCommon.h
    M llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp
    M llvm/lib/Target/X86/Disassembler/X86Disassembler.cpp
    M llvm/lib/Target/X86/MCTargetDesc/X86BaseInfo.h
    M llvm/lib/Target/X86/MCTargetDesc/X86MCCodeEmitter.cpp
    M llvm/lib/Target/X86/X86InstrControl.td
    M llvm/lib/Target/X86/X86InstrFormats.td
    M llvm/lib/Target/X86/X86InstrSSE.td
    A llvm/test/MC/Disassembler/X86/apx/jmpabs.txt
    A llvm/test/MC/X86/apx/jmpabs-att.s
    A llvm/test/MC/X86/apx/jmpabs-intel.s
    M llvm/utils/TableGen/X86DisassemblerTables.cpp
    M llvm/utils/TableGen/X86RecognizableInstr.cpp
    M llvm/utils/TableGen/X86RecognizableInstr.h

  Log Message:
  -----------
  [X86][MC] Support encoding/decoding for JMPABS (#72835)

JMPABS is a 64-bit only ISA extension, and acts as a near-direct branch
with an absolute target. The 64-bit immediate operand is treated an as
absolute effective address, which is subject to canonicality checks. It
is in legacy map 0 and requires REX2 prefix with `REX2.M0=0` and
`REX2.W=0`. All other REX2 payload bits are ignored.

blog: https://kanrobert.github.io/rfc/All-about-APX-JMPABS/

This patch
1. Extends `ExplicitVEXPrefix` to `ExplicitOpPrefix` for instrcutions
requires explicit `REX2` or `EVEX`
2. Adds `ATTR_REX2` and `IC_64BIT_REX2` to put `JMPABS` , `MOV EAX,
moffs32` in different tables to avoid opcode conflict

NOTE:
1. `ExplicitREX2Prefix` can be reused by the following PUSHP/POPP
instructions.
2. `ExplicitEVEXPrefix` will be used by the instructions promoted to
EVEX space for EGPR.