[all-commits] [llvm/llvm-project] 6273c5: [lldb][AArch64] Correctly invalidate svg when vg i...

[David Spickett via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 6273c5d4d3540204cb0d298cf1cf74ba94ed2a6c
      https://github.com/llvm/llvm-project/commit/6273c5d4d3540204cb0d298cf1cf74ba94ed2a6c
  Author: David Spickett <david.spickett at linaro.org>
  Date:   2025-06-19 (Thu, 19 Jun 2025)

  Changed paths:
    M lldb/source/Plugins/Process/Utility/RegisterInfoPOSIX_arm64.cpp

  Log Message:
  -----------
  [lldb][AArch64] Correctly invalidate svg when vg is written (#140875)

Recently the Linux Kernel has fixed a bunch of issues in SME support and
while testing that, I found two tests failing:
FAIL: test_za_register_dynamic_config_main_disabled
(TestZAThreadedDynamic.AArch64ZAThreadedTestCase)
FAIL: test_za_register_dynamic_config_main_enabled
(TestZAThreadedDynamic.AArch64ZAThreadedTestCase)

These tests write to vg during streaming mode from lldb and expect to
see that za has been resized to match it. Instead, it was unavailable.
lldb-server was sending the correct amount of data but lldb client was
expecting the old size.

Turns out that instead of a write to vg invalidating svg, it was
invalidating... something else. I'm still not sure how these tests ever
worked but with this one line fix, they pass again.

I did not see this issue with SVE or streaming SVE Z registers because
those always resize using the value of vg, and vg always has the value
we just wrote.

(remember that vg is the vector length of the **current** mode, not of
non-streaming mode, whereas svg is the vector length of streaming mode,
even if you are currently in non-streaming mode)



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