All PDB tests now pass when compiled without DIA on Windows, so they
pass with the native reader.
With this PR, the default reader changes to the native reader.
The plan is to eventually remove the DIA reader (see
https://discourse.llvm.org/t/rfc-removing-the-dia-pdb-plugin-from-lldb/87827
and #114906).
For now, DIA can be used by setting `plugin.symbol-file.pdb.reader` to
`dia` or by setting `LLDB_USE_NATIVE_PDB_READER=0` (mostly undocumented,
but used in tests).
If LLDB was built without the DIA SDK and the DIA reader is explicitly
requested (through `LLDB_USE_NATIVE_PDB_READER=0` or `settings set
plugin.symbol-file.pdb.reader dia`), LLDB should print a warning,
because it will use the native reader in any case
(https://github.com/llvm/llvm-project/pull/159769#discussion_r2367316980).
This PR adds the warning and a test when LLDB is not built with the SDK
on Windows. I don't think any builder runs this configuration, as there
are still five failing tests. I tested this locally with and without the
SDK.
If LLDB is built without the DIA SDK enabled, then the native plugin is
used regardless of `plugin.symbol-file.pdb.reader` or
`LLDB_USE_NATIVE_PDB_READER`. This made the test fail on Windows when
the DIA SDK was disabled
(https://github.com/llvm/llvm-project/issues/114906#issuecomment-3241796062).
This PR changes the requirement for the test from `target-windows` to
`diasdk` (only used in this test).
Initially suggested in
https://github.com/llvm/llvm-project/pull/149305#issuecomment-3113413702
- this PR adds the setting `plugin.symbol-file.pdb.use-native-reader`.
It doesn't remove support for `LLDB_USE_NATIVE_PDB_READER` to allow some
backwards compatibility. This was the suggested way to use the native
reader - changing that would mean users who set this, now use the DIA
reader. The setting has priority over the environment variable, though.
If the default gets flipped on Windows, the environment variable could
probably be removed as well.
This would make it possible to test both native PDB and DIA PDB in the
API tests (see linked PR).
