[PATCH 00/43] aarch64: Add missing test coverage, plus some fixes

[Richard Earnshaw]

On 08/05/2025 15:38, Richard Earnshaw (lists) wrote:
> On 21/04/2025 22:13, Alice Carlotti wrote:
>> This series addresses signifcant gaps in test coverage for aarch64 assembly and
>> disassembly.  There are also two functional fixes included in this series:
>>
>> Patch 01/43 disallows some incorrect SVE addressing modes that were being
>> misparsed as a different valid addressing mode.
>>
>> Patch 38/43 (with regenerated content in 39/43) fixes disassembly of the dgh
>> instruction.
>>
>> The patch I used to assess test coverage will be attached in a separate reply,
>> but is not suitable for use upstream.  Prior to this series, approximately 10%
>> of the entries in aarch64_opcode_table were not tested by the gas testsuite.
>> More specifically, 347 out of 3560 entries were not used in assembly and 414
>> out of 3560 entres were not used in disassembly.  After this series, all 3534
>> remaining entries are used in assembly, while just 64 entries are unused in
>> disassembly.  These 64 entries are all marked as pseudo instructions or as
>> having aliases (F_PSEUDO or F_HAS_ALIAS), so the gaps are clearly accounted
>> for.
>>
>> I have made virtually no attempt to improve the quality of tests for
>> instructions that are already tested, and where I have added to existing files
>> I have matched the existing test quality.  For new test files, however, I have
>> implemented tests that have much better coverage of the operand space
>> (including ensuring that all variable bits in encodings take both possible
>> values) - this is the same quality of (positive) test coverage that I would use
>> if adding new instructions.
>>
>> I have not investigated the coverage of error tests (or lack thereof) for
>> several reasons.  It is harder to assess coverage of invalid inputs, and
>> accurate errors are also less important than accurate assembly/disassembly of
>> valid code (though both are still important).  It is also likely that changes
>> that break existing error handling would also break valid assembly or
>> disassembly, or would already be picked up by an existing test.
>>
>>
>> The series consists of the following:
>>
>> Patches 01-03 address issues with the AARCH64_OPND_SVE_ADDR_R operand.  I
>> identified these issues originally when working on nearby code, but the
>> duplicate opcode table entries also show up as a gap in disassembly test
>> coverage.
>>
>> Patches 04-06 improve the regexes used in three existing assembly tests, to
>> facilitate later modifications to these test files.
>>
>> Patches 07-10 add instructions to four existing test files, in cases where the
>> previously untested instructions are part of a natural encoding group that was
>> already mostly covered by an existing test file.
>>
>> Patch 11 adjusts tests for the fmops instruction, which was already being
>> assembled, but only within an error test.
>>
>> Patches 12-33 add new tests to cover the rest of the testsuite gaps.  Some of
>> these tests include instructions that were already covered by an existing test;
>> I have explicitly mentioned all such cases in the commit messages.
>>
>> Patches 34-43 add missing F_PSEUDO, F_ALIAS and F_HAS_ALIAS annotations to
>> appropriate instructions.  This fixes dgh disassembly (with patch 40 cleaning
>> up the dgh tests).
>>
>>
>> Is this series ok for master?
> 
> Many thanks for this, it's a major improvement in our testing coverage.  You've detailed how you checked the coverage, but could you say a bit about how you've validated the additional tests for correctness?  The issue in patch 1 is evidence enough that bugs can slip in if we just assume that the output of the tools is correct.
> 
> I've minor issues with patches 5, 29 and 30, but the rest are all ok and those 3 are also OK with the suggested issues addressed.
> 
Oh, and patch 19 as well.

R.

> R.
>