riscv_dis_nonalias

Disassembler: Make some instruction non-aliases

• Status: WITHDRAWN
  (Jan worked on a similar patch and that is upstreamed)
• Based on
  • Fix zip/unzip on disassembler
• Branch: riscv-dis-nonalias
• Tracking PR: #16 (view Pull Request and Diff)
• Mailing List:
  • PATCH v1 (2022-07-09)

Conflicts With

• Upcoming (Pending): Disassembler: Support special (non-standard) encodings
  It also touches the definition of fence.tso.

Issue Solved

Certain instructions are defined as aliases (with INSN_ALIAS) but some of them have no "parent" instructions (without INSN_ALIAS).

As a result, if the disassembler has given an option of no-aliases, they will be printed as .4byte meaning not recognized.

Example

With following assembler file with -march=rv32i_zbkb,

_start:
    zip a0, a1
    unzip a2, a3

The output with objdump -d is like this:

80000028 <_start>:
80000028:   08f59513      zip     a0,a1
8000002c:   08f6d613      unzip   a2,a3

However, output with objdump -d -M no-aliases looks like this:

80000028 <_start>:
80000028:   08f59513      .4byte  0x8f59513
8000002c:   08f6d613      .4byte  0x8f6d613

Fixed Instructions

• zip (RV32_Zbkb)
• unzip (RV32_Zbkb)
• fence.tso (RV{32,64}I)

Note that zip and unzip fix is based on my previous patchset.