[debuginfo-tests] Stop using installed LLDB and remove redundancy

[jhenderson]

Summary

The removed code just replicated what use_llvm_tool does, plus looked for an installed LLDB on the PATH to use. In a monorepo world, it seems likely that if people want to run the tests that require LLDB, they should enable and build LLDB itself. If users really want to use the installed LLDB executable, they can specify the path to the executable as an environment variable "LLDB".

See the discussion in https://reviews.llvm.org/D95339#2638619 for more details.

[jmorse]

This works fine with our workflow at least, so a soft LGTM from me. I'd suggest waiting for a couple of days for more feedback though.

[aprantl]

If the intended effect is that we run the debuginfo-tests against the just-built LLDB this change makes sense to me in a monorepo world. Conditional LGTM from me.

[jhenderson]

In D102680#2775191, @aprantl wrote:

If the intended effect is that we run the debuginfo-tests against the just-built LLDB this change makes sense to me in a monorepo world. Conditional LGTM from me.

Thanks, yes that's the intended effect of this change. It's been a few days now, so I'll land this change.

debuginfo-tests/lit.cfg.py

llvm_config.with_environment('PATHTOCLANGPP',
                                add_host_triple(llvm_config.use_llvm_tool('clang++')))
   llvm_config.with_environment('PATHTOCLANGCL',
                                add_host_triple(llvm_config.use_llvm_tool('clang-cl')))
 else:
   print('Host triple {} not supported. Skipping dexter tests in the '
         'debuginfo-tests project.'.format(config.host_triple))
 
 # Check which debuggers are available:
-built_lldb = llvm_config.use_llvm_tool('lldb', search_env='LLDB')
-lldb_path = None
-if built_lldb is not None:
-    lldb_path = built_lldb
-elif lit.util.which('lldb') is not None:
-    lldb_path = lit.util.which('lldb')
+lldb_path = llvm_config.use_llvm_tool('lldb', search_env='LLDB')
 
 if lldb_path is not None:
     config.available_features.add('lldb')
 
 # Produce dexter path, lldb path, and combine into the %dexter substitution
 # for running a test.
 dexter_path = os.path.join(config.debuginfo_tests_src_root,
                            'dexter', 'dexter.py')