================ @@ -167,3 +167,49 @@ The result of this is that: Your VM configuration should have ports ``54321`` and ``49140`` forwarded for this to work. + +QEMU user mode emulation +------------------------ + +Serious testing of LLDB should be done using system mode emulation. The following +is presented for information only and is not a supported testing configuration +supported by the LLDB project. + +However, it is possible to run the test suite against user mode QEMU if you just +want to test a specific aspect of ``lldb`` and are ok ignoring a lot of expected +failures. This method can also be adapted for simulators with a qemu-like command +line interface. + +(``lldb-server`` cannot be tested using user mode QEMU because that does not +emulate the debugging system calls that ``lldb-server`` tries to make) + +Change ``LLDB_TEST_USER_ARGS`` to choose the ``qemu-user`` platform and +configure it for your architecture. The example below is for AArch64 and assumes +that ``qemu-aarch64`` is installed and on your path. + +If you need to override how the ``qemu-user`` platform finds the QEMU binary, +look up the rest of the platform's settings in LLDB. + +:: + + -DLLDB_TEST_USER_ARGS="--platform-name;qemu-user;--setting;platform.plugin.qemu-user.architecture=aarch64;--arch;aarch64" + +Also set ``LLDB_TEST_COMPILER`` to something that can target the emulated +architecture. Then you should be able to run ``ninja check-lldb`` and it will +run the tests on QEMU user automatically. + +You will see a number of failures compared to a normal test run. Reasons for +this can be, but are not limited to: + +* QEMU's built-in debug stub acting differently to ``lldb-server``. We try to + be compatible but LLDB is not regularly tested with QEMU user. + +* Tests that spawn new processes to attach to. QEMU user only emulates a single + process. + +* Watchpoints. Either these are not emulated or behave differently to real + hardware. Add ``--skip-category;watchpoint`` to ``-DLLDB_TEST_USER_ARGS`` to + skip those. + +* Lack of memory region information due to QEMU communicating this in the + GDB server format which LLDB does not use. ---------------- DavidSpickett wrote:
I haven't tested it so I won't throw shade at QEMU without evidence, but you're right that it's not just does X differently, it may support a different subset of X. So I have said something like that. https://github.com/llvm/llvm-project/pull/149057 _______________________________________________ lldb-commits mailing list lldb-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits
