Re: RFC: AArch64 Disassembler: Annotate undefined instructions
Project / Subsystem
binutils / rfc
Date
2026-04-30
Proposer
"Richard Earnshaw (foss)" <Richard.Earnshaw@arm.com>
Source type
public_inbox
Consensus
Proposed
Sentiment
—/10
Technical tradeoffs
- • Increased complexity in the disassembler.
- • Potential for false positives (incorrectly identifying data as code or vice versa).
- • Impact on disassembler performance (negligible, but measurable).
- • Benefit of providing more informative disassembly output in specific cases.
All attributes
- project
- binutils
- subsystem
- rfc
- patch_id
- —
- discussion_id
- 4d960fb5-bcb9-4066-a2e3-8c669fefd73b@arm.com
- source_type
- public_inbox
- title
- Re: RFC: AArch64 Disassembler: Annotate undefined instructions
- headline
- RFC: AArch64 Disassembler: Annotate undefined instructions
- tldr
- The disassembler would annotate disassembly of `.word` directives to indicate that they might be addresses, but there are concerns about the narrow use case.
- proposer
- "Richard Earnshaw (foss)" <Richard.Earnshaw@arm.com>
- consensus
- Proposed
- outcome
- proposed
- sentiment_score
- —
- technical_tradeoffs
-
- • Increased complexity in the disassembler.
- • Potential for false positives (incorrectly identifying data as code or vice versa).
- • Impact on disassembler performance (negligible, but measurable).
- • Benefit of providing more informative disassembly output in specific cases.
- series_id
- —
- series_role
- standalone
- series_parts
- []
- tags
-
- • binutils
- • disassembler
- • AArch64
- • undefined instructions
- • annotation
- bugzilla_url
- —
- date
- 2026-04-30T00:00:00.000Z
Re: RFC: AArch64 Disassembler: Annotate undefined instructions
Nick Clifton proposed a change to the AArch64 disassembler to annotate undefined instructions, specifically when they appear to be data rather than code. The disassembler would check if the closest preceding mapping symbol is $d and annotate accordingly. Richard Earnshaw questions the necessity and practicality of this approach, suggesting that it might only be triggered in contrived scenarios, and asks whether annotating .word directives that contain addresses is a real-world use case.