[all-commits] [llvm/llvm-project] e94c60: [lldb][Mach-O] Fix several bugs in x86_64 Mach-O c...

[Jason Molenda via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: e94c6091c93a72e9b81cf8d6394495d043b409d4
      https://github.com/llvm/llvm-project/commit/e94c6091c93a72e9b81cf8d6394495d043b409d4
  Author: Jason Molenda <jmolenda at apple.com>
  Date:   2025-06-30 (Mon, 30 Jun 2025)

  Changed paths:
    M lldb/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp
    M lldb/source/Plugins/Process/mach-core/RegisterContextUnifiedCore.cpp

  Log Message:
  -----------
  [lldb][Mach-O] Fix several bugs in x86_64 Mach-O corefile (#146460)

reading, and one bug in the new RegisterContextUnifiedCore class.

The PR I landed a few days ago to allow Mach-O corefiles to augment
their registers with additional per-thread registers in metadata exposed
a few bugs in the x86_64 corefile reader when running under different CI
environments. It also showed a bug in my RegisterContextUnifiedCore
class where I wasn't properly handling lookups of unknown registers
(e.g. the LLDB_GENERIC_RA when debugging an intel target).

The Mach-O x86_64 corefile support would say that it had fpu & exc
registers available in every corefile, regardless of whether they were
actually present. It would only read the bytes for the first register
flavor in the LC_THREAD, the GPRs, but it read them incorrectly, so
sometimes you got more register context than you'd expect. The LC_THREAD
register context specifies a flavor and the number of uint32_t words;
the ObjectFileMachO method would read that number of uint64_t's,
exceeding the GPR register space, but it was followed by FPU and then
EXC register space so it didn't crash. If you had a corefile with GPR
and EXC register bytes, it would be written into the GPR and then FPU
register areas, with zeroes filling out the rest of the context.



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